JPH09156014A - Absorbent sheet, manufacturing method thereof, and absorbent article - Google Patents

Abstract

(57) [Abstract] (Corrected) [PROBLEMS] Absorbent sheet in which a superabsorbent polymer is securely fixed without impairing the original absorption characteristics of the superabsorbent polymer, a manufacturing method thereof, and an absorbent article using the same. Offer of. SOLUTION: The absorbent sheet contains at least a superabsorbent polymer, a bulky cellulose fiber and a hydrophilic fine fiber, and the absorbent sheet is composed of a fiber aggregate 105 and a fiber web 108 and is integrated with each other. Body 105
Has an absorbent surface 102 and is mainly composed of bulky cellulose fibers, and the fiber web 108 contains bulky cellulose fibers and hydrophilic fine fibers, and the hydrophilic fine fibers on one surface side thereof. Is higher than the existing ratio on the other surface side, and the existing ratio of the hydrophilic fine fibers is low on the surface side.
Is adjacent to

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a sanitary napkin,
Absorbent sheet particularly preferably used for hygene pad, diaper, medical pad, breast milk pad, drip sheet, kitchen absorbent sheet, household cleaning sheet, pet under sheet, etc., a method for producing the same, and absorption using the same It relates to a sex article.

[0002]

2. Description of the Related Art Various methods for obtaining an absorbent sheet by fixing a superabsorbent polymer in an absorbent structure are known. For example, US Pat. No. 3,070,095, as shown in FIG.
Disperse the super absorbent polymer 16 on the tissue 30,
It is disclosed that after another tissue 31 is laminated on this, the superabsorbent polymer is pressed into the tissue by pressure bonding with a roller. However, in this method,
The superabsorbent polymer is only fixed in layers between the tissue layers and cannot fix a large amount of superabsorbent polymer. Therefore, when such an absorbent sheet is used as an absorbent body of an absorbent article, for example, the highly absorbent 16 polymer is converted into the tissue 30 by the exercise of the wearer,
In some cases, the liquid separates from the tissue 31 and a space is created between the tissues 30 and 31, and the liquid stays there.

US Pat. No. 3,670,731 discloses a method in which a superabsorbent polymer is dispersed between two paper layers,
Embossing is disclosed to secure the superabsorbent polymer within the embossing cavity. However, this method also has the same drawbacks as the above-mentioned roller pressure bonding method.

US Pat. No. 3,670,731 discloses that a superabsorbent polymer is sprinkled between two sheets of crepe paper and then quilted to hold the superabsorbent polymer in place. Disclosure. However, this method still has the drawback that a large amount of superabsorbent polymer cannot be fixed.

Further, Japanese Patent Publication No. 59-26467, Japanese Patent Laid-Open No. 54-123293, and Japanese Patent Laid-Open No. 54-141.
No. 099 gazette discloses that by spraying steam or spraying water on a tissue to moisten the tissue and then spraying a superabsorbent polymer to give tackiness to the superabsorbent polymer. Immobilizing superabsorbent polymers is disclosed. According to this method,
Although the superabsorbent polymer can be fixed to some extent, it cannot completely be prevented from falling off, and the fixing amount is still insufficient. Further, upon absorbing a liquid, the superabsorbent polymer swells in a layered form, and in some cases, absorption inhibition may occur due to gel blocking or the like.

Further, Japanese Patent Laid-Open No. 61-132697 discloses
In the papermaking process, is a highly absorbent polymer on the paper before drying.
After spraying the polymer, dry it
A method for producing absorbent paper containing mer is described.
You. According to this method, a certain amount of superabsorbent polymer
Can be fixed in the paper, but the fixed amount is at most 10 g / m
^TwoIt is a degree, and it cannot be said that the amount is sufficient. Also, profit
In the absorptive absorbent sheet, even on the surface that absorbs liquid
Due to the presence of superabsorbent polymers, such high absorption
The absorbable polymer is produced by dynamic action such as friction.
It has the drawback that it can easily fall off.

Further, a method is known in which a hot melt adhesive is applied to the entire surface of a tissue or the like and the superabsorbent polymer is fixed by the adhesive. According to this method, the superabsorbent polymer can be reliably fixed. However, since most of the surface of the superabsorbent polymer is covered with the hot melt adhesive, the swelling of the superabsorbent polymer and the absorption of liquid are inhibited.

As another method for fixing the superabsorbent polymer using the hot melt adhesive, there is a method of applying the hot melt adhesive in a spiral shape. According to this method, the above-mentioned swelling inhibition and absorption inhibition are small, and moreover, the superabsorbent polymer can be fixed efficiently. However, the spiral coating of the hot melt adhesive complicates the manufacturing process and equipment. Furthermore, since a large amount of superabsorbent polymer is fixed in a layered form, gel blocking of the superabsorbent polymer occurs when absorbing the liquid, and swelling inhibition of the liquid occurs.

On the other hand, an absorbent sheet using wood pulp produced by a dry method is also known. In such an absorbent sheet, if an attempt is made to increase the sheet strength by using a chemical binder, a highly-blended synthetic pulp, a low melting point synthetic fiber, or the like, the absorbent sheet becomes hydrophobic and the absorption rate is reduced. When the sheet strength is low, there is a drawback that when absorbing a liquid, the superabsorbent polymer swells, breaks the absorbent sheet and protrudes to the outside. Further, in order to increase the surface strength of the absorbent sheet, crepe paper may be laminated, but in this case, there is a problem that the cost becomes high.
Moreover, in any case, the fixation of the superabsorbent polymer to the wood pulp is insufficient, and the problem that the superabsorbent polymer is likely to fall off is not solved. Further, when the absorbent sheet is strongly compressed, there is a problem that the liquid absorption rate is unavoidably reduced.

In addition to the above-mentioned absorbent sheet, a method is also known in which a superabsorbent polymer is directly polymerized on a non-woven fabric as a base material and fixed on the non-woven fabric to obtain an absorbent sheet. However, when a non-woven fabric composed of hydrophilic fibers is used as the non-woven fabric, the superabsorbent polymer obtained as a result of the polymerization does not become particulate and is immobilized almost uniformly on the entire non-woven fabric, so the amount of liquid absorbed Has the disadvantage that it will decrease. On the other hand, when a non-woven fabric composed of hydrophobic fibers is used as the non-woven fabric, unlike the above-mentioned non-woven fabric composed of hydrophilic fibers, the superabsorbent polymer obtained as a result of the polymerization becomes particulate, but the whole absorbent sheet Since it is hydrophobic, it has a drawback that the absorption rate of liquid is slow. Moreover, in these methods, the unreacted monomer remains inevitable, so that the use of the absorbent sheet is limited from the viewpoint of safety of the monomer to the human body.

Accordingly, it is an object of the present invention to provide an absorbent sheet in which the superabsorbent polymer is securely fixed without impairing the original absorption characteristics of the superabsorbent polymer.

Another object of the present invention is to provide an absorbent sheet which can absorb liquid very smoothly without leaving it on the surface, can be quickly led to the whole superabsorbent polymer, and can effectively fix the liquid. To do.

Another object of the present invention is to provide an absorbent sheet which does not cause gel blocking by the superabsorbent polymer even when repeatedly absorbing a liquid, and which can exhibit the original absorption characteristics of the superabsorbent polymer. is there.

Another object of the present invention is to provide a method for easily manufacturing the absorbent sheet.

Further, it is an object of the present invention to provide an absorbent article having the above-mentioned absorbent sheet and having a high absorption performance.

[0016]

In order to achieve the above object,
As a result of intensive studies, the present inventors have made it possible to obtain a superabsorbent polymer by burying the superabsorbent polymer in the space formed between the fibers while the fibers constituting the absorbent sheet are wet. It has been found that a large amount can be immobilized and gel blocking of the superabsorbent polymer can be effectively prevented.

The present invention has been made based on the above findings, and is an absorbent sheet containing at least a superabsorbent polymer, bulky cellulose fibers and hydrophilic fine fibers, wherein the absorbent sheet is a fiber assembly. The fiber assembly is composed of a body and a fiber web, and the fiber assembly and the fiber web are integrated, and the fiber assembly has an absorbent surface and the absorbent surface side contains the superabsorbent polymer. None, and an average fiber length of 1 to 20 mm and a fiber roughness of 0.3 m
Mainly composed of bulky cellulose fibers of g / m or more, the fiber web has a bulkiness of 1 to 20 mm and a fiber roughness of 0.3 mg / m or more and bulky cellulose fibers and an average fiber length of 0.02 to 0.02. In addition to containing 0.5 mm of hydrophilic fine fibers, the existence ratio of the hydrophilic fine fibers on one surface side thereof is higher than the existence ratio of the other surface side, and the existence ratio of the hydrophilic fine fibers. Is adjacent to the fiber assembly on the lower surface side, and the superabsorbent polymer is contained inside the absorbent sheet and adheres to the fibers constituting the absorbent sheet. The above object is achieved by providing an absorbent sheet (hereinafter, referred to as "first absorbent sheet").

The present invention also provides a preferred method for producing the absorbent sheet, which is a bulky cellulose fiber having an average fiber length of 1 to 20 mm and a fiber roughness of 0.3 mg / m or more, and an average fiber length of 0.02 to 0. In the wet fibrous web containing 0.5 mm of hydrophilic fine fibers, the presence ratio of the hydrophilic fine fibers on one surface side is higher than that on the other surface side. A super absorbent polymer is sprinkled on the surface having a low proportion of fine fibers, and an average fiber length of 1 to 20 mm and a fiber roughness of 0.3 mg /
The present invention provides a method for producing an absorbent sheet, which comprises a step of superposing a fiber aggregate mainly composed of bulky cellulose fibers of m or more, and drying and integrating these.

The present invention also provides a liquid-absorbable surface layer as a preferred absorbent article using the above-mentioned absorbent sheet,
In an absorbent article having a liquid-retaining absorbent layer and a liquid-impermeable leakproof layer, at least the superabsorbent polymer, bulkiness, on the absorbent layer side of the surface layer or the absorbent layer or the leakproof layer. An absorbent sheet containing cellulose fibers and hydrophilic fine fibers, wherein the absorbent sheet is composed of a fiber aggregate and a fiber web, and the fiber aggregate and the fiber web are integrated. And
The fiber assembly has bulky cellulose fibers having an absorbent surface and not containing the superabsorbent polymer on the absorbent surface side, and having an average fiber length of 1 to 20 mm and a fiber roughness of 0.3 mg / m or more. Mainly, the fiber web is
Bulky cellulose fibers having an average fiber length of 1 to 20 mm and a fiber roughness of 0.3 mg / m or more and an average fiber length of 0.02 to
In addition to containing 0.5 mm of hydrophilic fine fibers, the existence ratio of the hydrophilic fine fibers on one surface side thereof is higher than the existence ratio of the other surface side, and the existence ratio of the hydrophilic fine fibers. Is adjacent to the fiber assembly on the lower surface side, and the superabsorbent polymer is contained inside the absorbent sheet and adheres to the fibers constituting the absorbent sheet. The present invention provides an absorbent article.

Further, the present invention is an absorbent sheet containing at least a superabsorbent polymer, bulky cellulose fibers and hydrophilic fine fibers, the absorbent sheet comprising a fiber aggregate and a fiber web. In addition, the fiber assembly and the fiber web are integrated, the fiber assembly has an absorption surface, the absorption surface side does not contain the superabsorbent polymer, and the average fiber length 1 ~ 20m
A bulky cellulose fiber having a fiber roughness of 0.3 mg / m or more in m and a hydrophilic fine fiber having an average fiber length of 0.02 to 0.5 mm, and the hydrophilic fine fiber on one surface side thereof. Is higher than the existence rate on the other surface side, and the fiber web has an average fiber length of 1 to 20 mm.
And is mainly composed of bulky cellulose fibers having a fiber roughness of 0.3 mg / m or more, and is adjacent to the fiber assembly on the surface side where the abundance ratio of the hydrophilic fine fibers in the fiber assembly is high, The superabsorbent polymer is contained in the absorbent sheet and is adhered to the fibers constituting the absorbent sheet (hereinafter, referred to as "second absorbent sheet"). That is, the above-mentioned object is achieved.

The present invention also provides a preferred method for producing the above-mentioned absorbent sheet, which comprises a wet fiber web mainly composed of bulky cellulose fibers having an average fiber length of 1 to 20 mm and a fiber roughness of 0.3 mg / m or more. The super absorbent polymer is sprinkled on the top of the fiber, and an average fiber length of 1 to 20 mm and a fiber roughness of 0.
It contains bulky cellulose fibers of 3 mg / m or more and hydrophilic fine fibers having an average fiber length of 0.02 to 0.5 mm, and the presence ratio of the hydrophilic fine fibers on one surface side of the other is A fiber aggregate having a higher abundance ratio on the surface side is superposed so that the abundance ratio of the hydrophilic fine fibers is higher and the fiber web is adjacent to each other, and a step of drying and integrating them is performed. The present invention provides a method for producing an absorbent sheet, which comprises:

Furthermore, the present invention provides a liquid-absorbable surface layer as a preferred absorbent article using the above-mentioned absorbent sheet,
In an absorbent article having a liquid-retaining absorbent layer and a liquid-impermeable leakproof layer, at least the superabsorbent polymer, bulkiness, on the absorbent layer side of the surface layer or the absorbent layer or the leakproof layer. An absorbent sheet containing cellulose fibers and hydrophilic fine fibers, wherein the absorbent sheet is composed of a fiber aggregate and a fiber web, and the fiber aggregate and the fiber web are integrated. And
The above fiber assembly has an absorbent surface and does not contain the above superabsorbent polymer on the absorbent surface side, and has a bulky cellulose fiber having an average fiber length of 1 to 20 mm and a fiber roughness of 0.3 mg / m or more, and The above-mentioned fiber web contains hydrophilic fine fibers having an average fiber length of 0.02 to 0.5 mm, and the presence ratio of the hydrophilic fine fibers on one surface side is higher than that on the other surface side. Is an average fiber length of 1
A bulky cellulosic fiber having a fiber roughness of 0.3 mg / m or more at 20 mm and having a high content ratio of the hydrophilic fine fibers in the fiber assembly and adjacent to the fiber assembly. The superabsorbent polymer is contained in the absorbent sheet and adheres to the fibers constituting the absorbent sheet, thereby providing an absorbent article.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION The first absorbent sheet and the second absorbent sheet of the present invention will be described below in detail with reference to the drawings. Here, FIG. 1 is a schematic view showing a cross section of the first absorbent sheet of the present invention, and FIG. 2 is a schematic view showing a cross section of the second absorbent sheet of the present invention.

First, the first absorbent sheet of the present invention will be described. As shown in FIG. 1, the first absorbent sheet 100 of the present invention is an absorbent sheet containing at least a superabsorbent polymer, bulky cellulose fibers and hydrophilic fine fibers. , Fiber assembly 105
And a fiber web 108. The fiber assembly 105 has an absorbent surface 102 and does not include a superabsorbent polymer on the absorbent surface 102 side. The fiber assembly 105 has an average fiber length of 1 to 20 mm and a fiber roughness of 0.3 m.
It is formed mainly of bulky cellulose fibers 12 of g / m or more.

On the other hand, as shown in FIG. 1, the fiber web 108 has an average fiber length of 1 to 20 mm and a fiber roughness of 0.3 m.
It contains bulky cellulose fibers 12 of g / m or more and hydrophilic fine fibers 14 having an average fiber length of 0.02 to 0.5 mm, and the proportion of the hydrophilic fine fibers on one surface side is the other. Is higher than the existence ratio on the surface side of. Then, the fiber web 108 has the fiber aggregate 105 on the side where the hydrophilic fine fibers are present in a low proportion.
Is adjacent to

Further, as shown in FIG. 1, the fiber aggregate 105 and the fiber web 108 are integrated. Further, the superabsorbent polymer 106 is contained inside the absorbent sheet 100 and is adhered to the fibers forming the absorbent sheet 100.

Thus, the first absorbent sheet 1 of the present invention
One of the features of 00 is that it has a monolithic structure including the fiber aggregate 105 and the fiber web 108 and the superabsorbent polymer 106 contained therein. More specifically, in the first absorbent sheet 100 of the present invention, mechanical entanglement between the fibers forming the fiber aggregate 105 and the fibers forming the fiber web 108, hydrogen bonding (and a strong auxiliary agent). Also, the fiber assembly 10 is formed by heat fusion or the like.
5 and the fibrous web 108 are integrated. By having such a structure, the above-mentioned superabsorbent polymer 106
Is securely fixed and can be prevented from falling off.
Moreover, the permeability and diffusivity of the liquid absorbed from the absorption surface 102 are further improved, and the liquid reaches the superabsorbent polymer 106 smoothly. In addition, gel blocking of the superabsorbent polymer 106 that has absorbed the liquid can be suppressed. Therefore, the first absorbent sheet 100 of the present invention has a completely different structure from the conventional absorbent sheet (FIG. 12) in which a superabsorbent polymer is sandwiched between two sheets of absorbent paper (that is, Conventional absorbent sheets have 2 plies,
The first absorbent sheet 100 of the present invention is a single sheet). Such integration is preferably achieved by superposing wet papermaking, as described below.

Next, the fibrous web 108 in the first absorbent sheet 100 of the present invention will be described. In the present invention, the "fiber web" means that the constituent fibers are not bound to each other at all in the wet state before the superabsorbent polymer is sprayed, or they are bound only slightly due to hydrogen bonding, mechanical entanglement and frictional force. In the state of having a very high degree of freedom, and after the drying, the constituent fibers are strongly bound to each other to have a sheet-like form.

The fiber web 108 is in a wet state before the superabsorbent polymer 106 is sprayed, and it is important that the fibers constituting the fiber web 108 have extremely high degrees of freedom with each other. . By dispersing the super absorbent polymer 106 on the fibrous web 108 in such a state, the super absorbent polymer 106 is embedded and fixed in the fibrous web 108. That is, the superabsorbent polymer 106 is three-dimensionally dispersed in the fibrous web 108. The fibrous web 108 has such strength that the superabsorbent polymer 106 does not deposit on the surface of the first absorbent sheet 100 after the fibrous web 108 and the fibrous aggregate 105 are integrated. It is also important that For this purpose, the fibrous web 108 preferably has a tensile strength in a wet state of 50 g or more, preferably 100 g or more, which is obtained by individually drying and sheeting the fiber web 108 according to JIS-P-8113. More preferably. In order to impart wet tensile strength to the fiber web 108, the fiber web 10
It is preferable that 8 is blended with a heat-melting adhesive fiber which will be described later, or a strength auxiliary agent (paper strength reinforcing agent) which will be described later.

The basis weight of the fibrous web 108 is preferred.
10g / m^Two~ 200g / m ^TwoAnd more preferred
10g / m^Two~ 100g / m^TwoAnd more preferred
20g / m^Two~ 80g / m^TwoIt is. The basis weight is
10g / m^TwoIf less than 10
At the time of swelling of No. 6, the superabsorbent polymer 106 is
There is a possibility that the sleeve 108 may project and fall off. one
On the other hand, the basis weight is 200 g / m^TwoAbove the fiber web
The density is too high, and the first absorbent sheet 100 is hard
Too much, the superabsorbent polymer 106 is solidified three-dimensionally.
Cannot be determined, liquid permeability is poor, and
May be uncomfortable to wear, so use within the above range.
Preferably.

The fiber web 108 will be described in more detail. The fiber web 108 has an average fiber length of 1 to 20 mm.
And includes bulky cellulose fibers having a fiber roughness of 0.3 mg / m or more and hydrophilic fine fibers having an average fiber length of 0.02 to 0.5 mm, and the hydrophilicity on one side thereof The abundance ratio of the fine fibers is higher than the abundance ratio on the other surface side. As a result, on the surface side where the hydrophilic fine fibers are present in a low proportion, the liquid absorption rate and the local liquid absorption are excellent, and the liquid permeability is high. On the other hand, on the surface side where the hydrophilic fine fibers are present in a high proportion, since the hydrophilic fine fibers have a high surface area, the liquid diffusibility is excellent. Therefore, it is possible to quickly diffuse the liquid that has permeated the surface side where the hydrophilic fine fibers are present in a low proportion. As described above, the fibrous web 108 has both a liquid absorbing property and a liquid diffusing property in spite of having a single structure. It should be noted that the fiber web 108 has the surface side where the hydrophilic fine fibers are present in a low proportion, and the fiber assembly 1 is
Adjacent to 05 is as described above. Less than,
For the sake of simplicity, of the surfaces of the fibrous web 108, the side having a low proportion of the hydrophilic fine fibers is called the first surface,
The surface side on which the hydrophilic fine fibers are present in a high proportion is referred to as a second surface.

As shown in FIG. 1, the fibrous web 108 is
Since the bulky cellulose fiber is the main component from the first surface to the vicinity of the first surface, it has a function of quickly absorbing the liquid and quickly transmitting the liquid to the second surface. That is, this region mainly functions as an "absorption-permeation layer" for the liquid. On the other hand, from the second surface to the second
Since the hydrophilic fine fibers are mainly contained in the vicinity of the surface, it has a function of quickly diffusing the liquid that has permeated from the first surface. That is, this region primarily functions as a "diffusion layer" for liquids. As described above, the fibrous web 108 is characterized by having both the absorbing and transmitting layer and the diffusing layer in a single structure, and as a result, has a high liquid absorbency and is extremely dry after absorbing the liquid. There is a feeling of slat.

As described above, there is a large difference in the liquid diffusivity between the first surface and the second surface. That is, the liquid quickly diffuses on the second surface side (diffusion layer) mainly composed of the hydrophilic fine fibers. On the other hand, on the first surface side (absorption / permeation layer) mainly composed of the above-mentioned bulky cellulose fibers, liquid absorption and permeation are rapid, but liquid diffusion is not so rapid. That is, the fibrous web 108 has a diffusion gradient with respect to the diffusion of the liquid in the thickness direction.

The proportion of the hydrophilic fine fibers present in the fibrous web 108 may gradually increase from the first surface to the second surface, but increases stepwise at a certain thickness. You may have.

On the other hand, the bulky cellulosic fibers may be present uniformly in the thickness direction of the fiber web 108, but more preferably the second side of the absorbent sheet of the present invention is more than the second side. The existence ratio is higher on the first surface side. That is, it is preferable that the abundance ratio of the bulky cellulose fibers has a gradient in the thickness direction of the fibrous web 108. The existence ratio is the second
The thickness may gradually increase from the surface toward the first surface, or may increase stepwise with a certain thickness as a boundary.

More specifically, the hydrophilic fine fibers are preferably contained at a depth of about 1/3 in the thickness direction from the second surface side of the fiber web 108, preferably about 5 based on the total amount thereof.
To about 70% by weight, more preferably about 10 to about 50% by weight
The diffusion layer that is present and is mainly composed of the hydrophilic fine fibers is formed. On the other hand, from the first surface side of the fiber web 108 to a depth of about 2/3 in the thickness direction, the bulky cellulose fibers are preferably about 60 to about 100% by weight based on the total amount, Preferably about 70 to about 9
The amount of 7% by weight is present, and the absorbing / permeating layer mainly composed of the bulky cellulose fiber is formed.

As described above, the distribution of the bulky cellulosic fibers and the hydrophilic fine fibers may be gradually increased in the thickness direction of the fibrous web 108, and stepwise with a certain thickness as a boundary. May be increased to. Then, both the bulky cellulose fibers and the hydrophilic fine fibers have a gradient in their distribution in the thickness direction of the fiber web 108.
In a particularly preferred embodiment of, the liquid absorption and permeability and the liquid diffusivity can be more remarkably exhibited.

The blending ratio of the bulky cellulose fiber and the hydrophilic fine fiber in the fibrous web 108 is not particularly limited, but the bulky cellulose fiber is based on 100 parts by weight of the fibrous web. 50-97
It is preferably contained in an amount of 70 parts by weight, more preferably 70 to 95 parts by weight. If the blending ratio of the bulky cellulose fibers is less than 50 parts by weight, the bulky network structure may be insufficient and a fiber web having both permeation and diffusion may not be obtained. If the blending ratio exceeds 97 parts by weight, the blending ratio of the hydrophilic fine fibers becomes low and the diffusivity becomes insufficient.
It is preferable to be within the above range.

On the other hand, the hydrophilic fine fibers are preferably contained in an amount of 3 to 50 parts by weight, more preferably 5 to 30 parts by weight, based on 100 parts by weight of the fiber web. If the blending ratio of the hydrophilic fine fibers is less than 3 parts by weight, the diffusivity becomes insufficient, and if the blending ratio of the hydrophilic fine fibers exceeds 50 parts by weight, the hydrophilicity on the first surface side is high. Since the blending ratio of the fine fibers of (3) increases and the permeability becomes insufficient, it is preferably within the above range.

If necessary, the fiber web 108 may be added with a heat-melting adhesive fiber which is melted by heating and adheres to each other. By adding such a heat-meltable adhesive fiber, it is possible to maintain the structural stability of the fiber web 108 when it is wet.

It is preferable to add 2 to 30 parts by weight, and more preferably 3 to 20 parts by weight, based on 100 parts by weight of the above-mentioned fibrous web. If the amount added is less than 2 parts by weight, the strength when actually absorbing a liquid becomes insufficient, or the bulky cellulose fibers and the hydrophilic fine fibers in the fiber web 108 are mixed. It is not preferable because the diffusion gradient may not be maintained. On the other hand, if the addition amount exceeds 30 parts by weight, the hydrophilicity of the entire fibrous web 108 decreases,
The liquid absorption rate and the liquid diffusing ability may be insufficient, which is not preferable.

Other optional components that can be added to the fiber web 108 include other pulps such as softwood pulp, hardwood pulp and straw pulp, and polyamine epichlorohydrin resin, dialdehyde starch, sponge as a strong auxiliary agent. And carboxymethyl cellulose and the like. These ingredients are preferably 0-30 based on 100 parts by weight of the fibrous web.
Parts by weight, more preferably 0 to 20 parts by weight can be added.

The thickness of the fibrous web 108 is not particularly limited, but the thickness under a load of 2.5 g / m ² is 0.2 to ² mm.
Is preferable, and 0.2-1 mm is more preferable. If the thickness is less than 0.2 mm, the fibrous web may be too thin to exhibit the functions of permeation and diffusion. If the thickness exceeds 2 mm, smooth transmission of liquid, permeation and diffusion, may occur. In some cases, it may be difficult to occur, so that it is preferable to set it within the above range.

In a particularly preferred embodiment of the fibrous web 108, the fibrous web 108 contains 70 to 95 parts by weight of the bulky cellulose fiber and 5 parts by weight of the hydrophilic fine fiber based on 100 parts by weight of the fibrous web. ˜30 parts by weight, and 2 to 30 parts by weight of the heat-meltable adhesive fiber; and the basis weight is 10 to 200 g / m ² .

Next, the fiber web 108 is formed.
The above-mentioned bulky cellulose fibers, hydrophilic fine fibers, and the above heat-meltable adhesive fibers will be described.

First, the bulky cellulose fiber will be described. The bulky cellulose fibers have an average fiber length of 1 to 20 mm and a fiber roughness of 0.3.
Any cellulose fiber may be used as long as it is at least mg / m and is bulky. As cellulose fiber,
For example, natural cellulose such as wood pulp and cotton, regenerated cellulose such as rayon and cupra can be used.
From the viewpoint of cost, it is preferable to use wood pulp, and particularly softwood kraft pulp is preferably used.
These cellulose fibers may be used alone or in combination of two or more. The bulky cellulose fibers preferably have an average fiber length of 2 to 10 mm, more preferably 2 to 5 mm. Average fiber length is 1m
If it is less than m, the bulky network structure cannot be formed, and the hydrophilic fine fibers cannot pass through the bulky network structure as described later. When the average fiber length exceeds 20 mm, the dispersibility in water deteriorates and a uniform network structure cannot be formed. In the present invention, “bulky fiber” means that the fiber shape has a three-dimensional structure such as a twisted structure, a crimp structure, a bent and / or branched structure, or an extremely thick fiber cross section (for example, a fiber roughness of 0. 3 mg / m or more).

The bulky cellulose fiber has a fiber roughness of 0.3 mg / m or more. Fiber roughness 0.3
When the amount is at least mg / m, the cellulose fibers are accumulated in a bulky state and the bulky network structure is formed. Further, the movement resistance of the liquid is small, and the passing speed of the liquid is high. The bulky cellulose fiber has an average fiber length of 1 to 20 mm and a fiber roughness of 0.3 mg /
m or more, and the roundness of the fiber cross section is 0.5
It is more preferable that it is from 1 to 1, because the above-mentioned effects are further exhibited.

In the present invention, the "fiber roughness" means a fiber having a non-uniform thickness, such as wood pulp.
It is used as a scale showing the thickness of the fiber, and for example, a fiber roughness meter (FS-200, KAJANNI ELECTRONIC
S LTD.).

As described above, with respect to the fiber roughness, the bulky cellulose fiber preferably has a fiber roughness of 0.3 mg / m or more, and a more preferable fiber roughness is 0.
3 to 2 mg / m, and more preferable fiber roughness is 0.3.
It is 2-1 mg / m. The roundness of the fiber cross section is more preferably 0.55 to 1.

Examples of cellulose fibers having a fiber roughness of 0.3 mg / m 2 or more include softwood kraft pulp [Federal
"ALBACEL" (trade name) made by Paper Board Co., and PT
Inti Indorayon Utama's "INDORAYON" (brand name)] and the like.

As described above, the bulky cellulose fiber preferably has a roundness of the fiber cross section of 0.5 to 1, but when the roundness is within this range, the bulky cellulose fiber is formed. The fibers become thick and round, and when they become an aggregate, they become bulky as a cross-sectional structure of the aggregate, and since the fibers are not in close contact with each other, hydrogen bonding is difficult and a bulky structure can be maintained.

Further, as described above, in the present invention, it is preferable to use wood pulp as the cellulose fiber, but generally the cross section of the wood pulp is flat due to the delignification treatment, and most of the roundness thereof is It is less than 0.5. In order to make the roundness of the wood pulp 0.5 or more, for example, the wood pulp having a fiber roughness of 0.3 mg / m or more is mercerized to swell the cross section of the wood pulp. Good. That is, the bulky cellulose fiber,
It is also preferably mercerized pulp.

Thus, the roundness of the fiber cross section is 0.5 to
As the cellulose fiber of 1, mercerized pulp having a circularity of 0.5 to 1 obtained by mercerizing wood pulp is preferable. Examples of commercially available mercerized pulps that can be used in the present invention include ITT Rayoni
er Inc.'s "FILTRANIER" (product name) and the company's "PO"
ROSANIER ”(brand name) and the like.

Other preferred examples of the above bulky cellulose fibers having an average fiber length of 1 to 20 mm and a fiber roughness of 0.3 mg / m or more include intramolecular and intermolecular crosslinking of the cellulose fibers. There is a crosslinked cellulose fiber obtained by the above. Such a crosslinked cellulose fiber is preferable because it does not swell even when wet with a liquid, has a small amount of twisting / sagging, and can maintain a bulky structure without lowering the strength.

The method for crosslinking the cellulose fibers is not particularly limited, and examples thereof include a crosslinking method using a crosslinking agent. Examples of such cross-linking agents include N-methylol compounds such as dimethylol ethylene urea and dimethylol dihydroxy ethylene urea; polycarboxylic acids such as citric acid, tricarballylic acid and butane tetracarboxylic acid; polyols such as dimethyl hydroxyethylene urea. ;
Examples thereof include cross-linking agents for polyglycidyl ether compounds. In particular, a cross-linking agent of a polycarboxylic acid or a polyglycidyl ether-based compound that does not generate formalin or the like which is harmful to the human body during cross-linking is preferable.

The amount of the cross-linking agent used is preferably 0.2 to 20 parts by weight with respect to 100 parts by weight of the cellulose fibers. If the amount used is less than 0.2 parts by weight, the cross-linking density of the cellulose fibers is low, so the elastic modulus may decrease significantly when wet, and if the amount used exceeds 20 parts by weight, the cellulose fibers will be Since the cellulose fiber may become too rigid and become brittle when stress is applied, it is preferably within the above range.

In order to crosslink the above-mentioned cellulose fibers with the above-mentioned crosslinker, for example, an aqueous solution of the above-mentioned crosslinker, to which a catalyst is added if necessary, is impregnated with the above-mentioned cellulose fibers to design an aqueous solution of the crosslinker. The cellulose fibers are dehydrated so that the adhesion amount is obtained, and then heated to the crosslinking temperature, or
Alternatively, an aqueous solution of a cross-linking agent is sprayed onto the above-mentioned cellulose fibers by spraying or the like so as to have a designed adhesion amount, and then heated to a cross-linking temperature to cause a cross-linking reaction.

As the above-mentioned crosslinked cellulose fiber, commercially available products can be used. Such cross-linked cellulosic fibers are available from Weyerhaeuser Paper Co.
gh Bulk Additive ”(trade name) and the like.

A more preferred crosslinked cellulose fiber has an average fiber length of 1 to 20 mm and a fiber roughness of 0.3 mg /
It is a cross-linked cellulose fiber having a circularity of 0.5 to 1 and a circular cross section of 0.5 or more. Further, the crosslinked cellulose fibers of the mercerized pulp described above are also preferable.

Next, the hydrophilic fine fibers will be described. The surface of the hydrophilic fine fibers is hydrophilic, and the average fiber length thereof is 0.02 to 0.5 mm, preferably 0.03 to 0.3 mm. If the average fiber length of the hydrophilic fine fibers is less than 0.02 mm, in the preferred method for producing the fiber web described below, the hydrophilic fine fibers slip through the papermaking wire, and the hydrophilicity of the hydrophilic fine fibers on the papermaking wire. Fine fibers cannot be deposited. When the average fiber length of the hydrophilic fine fibers exceeds 0.5 mm, the hydrophilic fine fibers are formed of the bulky cellulose fibers in the preferred method for producing the fiber web described below. It cannot slip through the network structure and is not deposited on the papermaking wire.

If the above requirements are satisfied, the hydrophilic fine fibers are not particularly limited. For example, cellulose fibers such as pulp, cotton and rayon; hydrophilic synthetic fibers such as polyacrylonitrile and polyvinyl alcohol; inorganic fibers such as kaolin, bentonite and hydrotalcite can be used. These hydrophilic fine fibers may be used alone or in combination of two or more.

As the hydrophilic fine fibers, commercially available products may be used. For example, pulp floc (trade name) manufactured by Sanyo Kokusaku Pulp Co., Ltd., which is obtained by beating wood pulp such as softwood pulp and hardwood pulp, then mechanically crushing and then separating with a sieve of 0.5 mm or less, etc. To be As another example, cellulose fibers such as wood pulp are mechanically crushed, then hydrolyzed with an acid, and then mechanically crushed to obtain cellulose fine fibers (KC Flock manufactured by Sanyo Kokusaku Pulp Co., Ltd. Trade name) and Avicel (trade name) manufactured by Asahi Kasei Co., Ltd.]. In addition, commercially available inorganic fine fibers include hydrous magnesium silicate fibers [ATE PLUS M manufactured by Mizusawa Chemical Industry Co., Ltd.].
L-30 (trade name)] and the like. Among these commercially available products, cellulose fine fibers obtained by pulverizing pulp into fine particles can be obtained at a lower cost and can be preferably used.

Next, the heat-meltable adhesive fiber that is optionally used in the fiber web 108 will be described.
As the heat-melting adhesive fiber, fibers that are melted by heating and adhere to each other can be used. Specifically, for example, polyolefin fibers such as polyethylene, polypropylene and polyvinyl alcohol, polyester fibers, polyethylene-polypropylene. Examples thereof include composite fibers, polyethylene-polyester composite fibers, low melting point polyester-polyester composite fibers, polyvinyl alcohol-polypropylene composite fibers having a hydrophilic fiber surface, and polyvinyl alcohol-polyester composite fibers. When using a conjugate fiber, any of a core-sheath type conjugate fiber and a side-by-side type conjugate fiber can be used. These heat fusible adhesive fibers can be used alone or in combination of two or more. Examples of the heat-meltable adhesive fiber preferably used in the present invention include polyvinyl alcohol and polyester.

The heat-meltable adhesive fiber generally has a fiber length of 2 to 60 mm and a fiber diameter of 0.5 to 3 denier.

Next, the superabsorbent polymer 106 contained in the first absorbent sheet 100 of the present invention will be described. As shown in FIG. 1, the super absorbent polymer 10 described above is used.
6 is contained in the inside of the 1st absorbent sheet 100 of this invention, and is dispersed in the space formed between the fibers which comprise the 1st absorbent sheet 100 of this invention. More specifically, as shown in FIG. 1, the superabsorbent polymer 106 described above is used.
Are preferably contained mainly inside the fibrous web 108 and are dispersed in the space formed between the fibers constituting the fibrous web 108. As a result, the superabsorbent polymer 106 is reliably fixed in the first absorbent sheet 100 of the present invention and the occurrence of gel blocking is suppressed. In addition, here, "superabsorbent polymer 10
"6 is contained in the first absorbent sheet 100" does not mean that the superabsorbent polymer 106 does not exist on the surface of the first absorbent sheet 108 of the present invention at all, and will be described later. In the preferred method for producing the first absorbent sheet according to the present invention, a trace amount of the superabsorbent polymer unavoidably present on the surface of the absorbent sheet is acceptable, and most of the above-mentioned superabsorbent polymers 106 are present It exists inside the first absorbent sheet 100.

The superabsorbent polymer 106 is adhered to the fibers forming the first absorbent sheet 100 of the present invention, preferably the fibers forming the fiber web 108. As a result, the immobilization of the superabsorbent polymer 106 becomes stronger and the gel blocking thereof is further suppressed. Here, the superabsorbent polymer 106 does not need to have all the particles adhered to the fiber. Based on the total amount of the superabsorbent polymer 106, 50% by weight or more is preferably adhered to the fiber, and in particular,
It is preferable that 70% by weight or more is bonded to the fiber.
If the adhesion amount of the superabsorbent polymer 106 is less than 50% by weight, the effect of immobilization may not be sufficiently exhibited, which is not preferable. The method of adhering the superabsorbent polymer 106 to the fibers will be described later.

When the particle aggregating type superabsorbent polymer is used as the above-mentioned superabsorbent polymer 106, which is a secondary particle by aggregating a spherical polymer as a primary particle, all of the primary particles are If the secondary particles are partially adhered to the fiber, the superabsorbent polymer will be fixed to the fiber.

Preferably, the superabsorbent polymer 106 described above is used.
Are not dispersed in layers in the first absorbent sheet 100 of the present invention, but are dispersed in three dimensions as shown in FIG. Therefore, the superabsorbent polymer can be dispersed in a large amount. That is, while the upper limit of the spreading basis weight of the superabsorbent polymer in the conventional absorbent sheet in which the superabsorbent polymer is dispersed in a layer (that is, two-dimensional) is generally about 50 to 100 g / m ² , First of the present invention
In the absorbent sheet 100, the super absorbent polymer 1 described above is used.
Since 06 can be dispersed three-dimensionally, the upper limit of the basis weight of the superabsorbent polymer 106 to be spread is about 200 to 3
It can be set to 00 g / m ^2, and the spread basis weight of the super absorbent polymer 106 can be increased to about 3 times that of the conventional absorbent sheet. Therefore, the first absorbent sheet 100 of the present invention dramatically increases the amount of liquid absorbed as compared with the conventional absorbent sheet. Furthermore, the above superabsorbent polymer 10
Since 6 is three-dimensionally dispersed and is used in combination with the transmission layer and the diffusion layer, the original absorption performance of the superabsorbent polymer 106 is more effectively exhibited. That is, even when the same amount of superabsorbent polymer as that of the conventional absorbent sheet is used, the absorbent performance can be further improved, and as a result, the absorbent sheet can be made extremely thinner than the conventional product. In addition, since it is possible to increase the spray basis weight, it can be suitably used as an absorbent body such as a disposable diaper that requires a large absorbent capacity.

The super absorbent polymer 106 preferably has a spray basis weight of 1 to 300 g / m ^2.
More preferably 300 g / m ² and 10 to 20
More preferably 0 g / m ² and ²⁰ to 150 g
/ M ² is particularly preferable. The above spray basis weight is 1g
If it is less than / m ² , the water absorption capacity is insufficient and sufficient function cannot be exhibited. On the other hand, when the spread basis weight is more than 300 g / m ² , the fiber web 108 and the fiber aggregate 105 are
It is preferable that the content be within the above range, because the adhesive strength with the polymer and the superabsorbent polymer 106 will easily fall off.

As the superabsorbent polymer 106, those capable of absorbing / holding 20 times or more the liquid of its own weight and capable of gelling are preferable. Examples of such superabsorbent polymers include starch, cross-linked carboxymethyl cellulose, polymers or copolymers of acrylic acid or alkali metal salts of acrylic acid, polyacrylic acid and its salts, and polyacrylate graft weight. You can list coalescence. As the polyacrylic acid salt, sodium salt can be preferably used. Acrylic acid may be a comonomer such as maleic acid, itaconic acid, acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, 2- (meth) acryloylethanesulfonic acid, 2-hydroxyethyl (meth) acrylate or styrenesulfonic acid. A copolymer obtained by copolymerizing the superabsorbent polymer in a range not deteriorating the performance thereof can also be preferably used.

Next, the fiber assembly 105 having the absorbent surface 102 in the first absorbent sheet 100 of the present invention will be described. Here, the “absorption surface” refers to a surface that first absorbs liquid when the first absorbent sheet 100 of the present invention absorbs liquid. That is, when the first absorbent sheet 100 of the present invention is used, the liquid is mainly absorbed from the fiber assembly 105 side.

The fiber assembly 105 has the absorbing surface 1
The 02-side does not include the superabsorbent polymer 106. Here, "not containing a super-absorbent polymer" does not mean that the fiber assembly 105 does not contain the super-absorbent polymer 106 on the absorbent surface 102 side at all, and does not mean that the present invention to be described later. It means that a small amount of superabsorbent polymer inevitably mixed in the preferred method for producing the first absorbent sheet 100 allows, but does not substantially contain the superabsorbent polymer.

The fiber assembly 105 has an average fiber length of 1 to
A bulky cellulose fiber having a fiber roughness of 0.3 mg / m or more at 20 mm is mainly used, and it is obtained by mechanical entanglement, physical entanglement, heat adhesion, or the like of the fiber.
For example, paper or non-woven fabric can be used. As the paper, it is possible to use paper obtained by wet papermaking, crepe-processed paper, or the like.

The fiber aggregate 105 has an average fiber length of 1-2.
It is as described above that the bulky cellulose fiber having a fiber roughness of 0.3 mg / m or more at 0 mm is mainly used, but the bulky cellulose fiber is preferably 30 based on 100 parts by weight of the fiber aggregate. It is contained in an amount of at least 1 part by weight, more preferably 50 to 98 parts by weight. For the details of the bulky cellulose fiber, the description of the bulky cellulose fiber forming the fiber web 108 is appropriately applied.

Further, a heat-melting adhesive fiber may be added to the fiber assembly 105. Such a heat-meltable adhesive fiber is preferably contained in an amount of 1 to 50 parts by weight, more preferably 3 to 30 parts by weight, based on 100 parts by weight of the fiber assembly. For the details of the heat-melting adhesive fiber, the detailed description of the heat-melting adhesive fiber forming the fiber web 108 is appropriately applied.

As other components that can be added to the fiber assembly 105, there are strong auxiliary agents. As the strong auxiliary agent, the strong auxiliary agent detailed in the description of the first absorbent sheet can be used. The strength aid is preferably contained in an amount of 0 to 30 parts by weight based on 100 parts by weight of the fiber assembly, and more preferably 0.
~ 20 parts by weight.

For the same reason as in the case of the fibrous web 108, the fibrous aggregate 105 has a tensile strength in wet of 50 g or more as measured by JIS-P-8113 by drying the fibrous web alone to form a sheet. Is more preferable, and it is more preferable that the amount is 100 g or more.

The fiber aggregate 105 has a basis weight of 10
~ 200 g / m ² , preferably 10-50 g
/ M ² is more preferable. The basis weight is 10 g /
If it is less than m ^2, when the superabsorbent polymer 106 swells, the superabsorbent polymer 106 will be absorbed by the fiber aggregate 105.
May protrude and fall off. On the other hand, if the basis weight is more than 200 g / m ² , the density of the fiber assembly 105 may be too high, and the first absorbent sheet 100 of the present invention may be too hard. .

The fiber assembly 105 may be manufactured in advance before manufacturing the fiber web 108, or when manufacturing the first absorbent sheet 100 of the present invention.
The fiber web 108 may be manufactured at the same time.

As described above, the first absorbent sheet 1 of the present invention
00 is the fiber aggregate 105 and the fiber web 108.
And mainly formed of the super absorbent polymer 106.
And these in the first absorbent sheet 100
The preferred range of the grammage of the fiber aggregate 105 is
Is 10-200 g / m^TwoAnd the above superabsorbent polymer
106 spray basis weight is 1 to 300 g / m^TwoAnd the above fiber
Weibob 108 has a basis weight of 10 to 200 g / m.^TwoIt is.
A more preferable range is that the basis weight of the fiber assembly 105 is 1
0-100g / m^TwoAnd the above superabsorbent polymer 10
6 spraying basis weight is 5-200 g / m^TwoAnd the above fiber c
The basis weight of Eve 108 is 10 to 100 g / m ^TwoIt is.

[0081] Also, the first basis weight of the total of the absorbent sheet 100 of the present invention is preferably 21~500g / m ^2, more preferably from 30~300g / m ^2, 50~200g / More preferably m ² .

Furthermore, the first absorbent sheet 100 of the present invention.
Has a thickness of 0.3 to 5 mm under a load of 2.5 g / cm ^2.
Is preferably, and more preferably 0.5 to 3 mm. Further, in the case of an ultrathin absorbent sheet, the thickness under load of 2.5 g / cm ² is 0.3 to 1.5.
mm is preferable, and 0.3 to 1.2 mm is more preferable.

In the first absorbent sheet 100 of the present invention having the above-mentioned structure, the single structure has the diffusion gradient of the liquid. More specifically, since liquid absorption is high on the absorbent surface 102 side of the first absorbent sheet 100, there is little liquid remaining on the absorbent surface 102. Then, the absorbed liquid quickly transfers to the superabsorbent polymer 106, and the fibrous web 108 having a particularly high diffusivity.
On the second surface side of the first absorbent sheet 100 is diffused over the entire surface of the first absorbent sheet 100. Thus, the first absorbent sheet 1
00 has a liquid permeation / diffusion / fixing function in its single structure, so that the liquid can be fixed with the superabsorbent polymer 106 more quickly and reliably. Further, when the first absorbent sheet 100 absorbs a large amount of liquid, the liquid is quickly transmitted to the superabsorbent polymer 106 and absorbed therein. Even when the liquid cannot be completely held by the superabsorbent polymer 106, the liquid does not leak out because it is diffused on the second surface side of the fibrous web 108. in this way,
The first absorbent sheet 100 of the present invention is particularly effective when absorbing a large amount of liquid at one time and when using a superabsorbent polymer having a slow absorption rate.

Next, the second absorbent sheet of the present invention will be described. As shown in FIG. 2, the second absorbent sheet 200 of the present invention is an absorbent sheet containing at least a superabsorbent polymer, bulky cellulose fibers and hydrophilic fine fibers. , Fiber assembly 205
And a fiber web 208. The fiber assembly 205 has an absorbent surface 202 and does not include a superabsorbent polymer on the absorbent surface 202 side. The fiber aggregate 205 has an average fiber length of 1 to 20 mm and a fiber roughness of 0.3.
It contains bulky cellulose fibers 12 of mg / m or more and hydrophilic fine fibers 14 having an average fiber length of 0.02 to 0.5 mm, and the proportion of the hydrophilic fine fibers on one surface side is the other. Is higher than the existence ratio on the surface side of.

On the other hand, as shown in FIG. 2, the fiber web 208 has an average fiber length of 1 to 20 mm and a fiber roughness of 0.3 m.
It is mainly composed of bulky cellulose fibers 12 of g / m or more. The fiber web 208 is the fiber assembly 2 described above.
No. 05 is adjacent to the fiber assembly 205 on the side where the above-mentioned hydrophilic fine fibers are present in a high proportion. For the sake of simplicity, as in the description of the fibrous web 108 in the first absorbent sheet 100, the proportion of the hydrophilic fine fibers present in the surface of the fiber assembly 205 of the second absorbent sheet 200 is the same. The surface side having a low abundance is referred to as a first surface, and the surface side having a high proportion of the hydrophilic fine fibers is referred to as a second surface.

Further, as shown in FIG. 2, the fiber aggregate 205 and the fiber web 208 are integrated. Further, the superabsorbent polymer 206 is contained inside the absorbent sheet 200, and the absorbent sheet 2
Bonded to the fibers that make up 00.

Thus, the second absorbent sheet 2 of the present invention
One of the characteristics of 00 is that, like the first absorbent sheet 100, it includes a fiber aggregate 205 and a fiber web 208 and has a super-absorbent polymer 206 contained therein. Is. The integrated structure of the second absorbent sheet of the present invention is the same as the case of the first absorbent sheet and will not be described here. However, the detailed description of the integrated structure of the first absorbent sheet is described in the above. 2 Applicable to absorbent sheets as well.

Next, the fibrous web 208 in the second absorbent sheet 200 of the present invention will be described. The fiber web 208 has an average fiber length of 1 to 20 m as described above.
It is formed mainly of bulky cellulosic fibers having a fiber roughness of 0.3 mg / m or more at m, and moreover, the surface side where the abundance ratio of the hydrophilic fine fibers in the fiber assembly 205 is high, that is, the second It is adjacent to the fiber assembly 205 on the surface side. By using such bulky cellulosic fibers as the fibers constituting the fiber web 208, not only the dispersibility and the degree of immobilization of the superabsorbent polymer 206 are further improved, but especially the fiber web is used during wet papermaking. The drainage property of 208 can be controlled more easily. Further, since the bulky cellulose fiber can form a bulky and highly voidy fiber web, the superabsorbent polymer 206 is three-dimensionally embedded / dispersed in the fiber web 208, and easily fixed, and The occurrence of gel blocking of the superabsorbent polymer 206 can also be suppressed.

The bulky cellulose fibers are contained in an amount of preferably 30 parts by weight or more, and more preferably 50 to 99 parts by weight, based on 100 parts by weight of the fiber web.

For the details of the bulky cellulose fibers constituting the fibrous web 208, the description of the bulky cellulose fibers used in the first absorbent sheet 100 can be applied as appropriate.

It is also preferable to add to the above-mentioned fibrous web 208 the strong auxiliary agent detailed in the description of the above-mentioned first absorbent sheet. These strong auxiliaries are 0 to 30 based on 100 parts by weight of the fibers constituting the fiber web 208.
Parts by weight, preferably 0 to 20 parts by weight can be added.

Further, in order to increase the strength of the fibrous web 208, ordinary cellulose fibers capable of forming hydrogen bonds, that is, wood pulp, non-wood pulp, etc. may be blended.

In this case, the fibrous web 208 is based on 100 parts by weight of the fibrous web, 30 to 99 parts by weight of the bulky cellulose fibers, 1 to 70 parts by weight of the wood pulp or non-wood pulp, and 0 to a strong adjuvant
It preferably comprises 30 parts by weight. More preferably, based on 100 parts by weight of the fiber web, 50 to 95 parts by weight of the bulky cellulose fiber, 5 to 50 parts by weight of the wood pulp or non-wood pulp, and 0 to 20 parts by weight of the strong auxiliary agent. Consists of parts.

Furthermore, it is also preferable to add a heat-melting adhesive fiber to the fiber web 208. By adding such a heat-meltable adhesive fiber, the structure of the absorbent sheet of the present invention can be kept stable even when it is wet. Note that, for the details of the heat-melting adhesive fiber, the description of the heat-melting adhesive fiber used in the first absorbent sheet 100 is appropriately applied.

In this case, the fiber web 208 contains 30 to 99 parts by weight of the bulky cellulose fiber and 1 to 50 parts by weight of the heat-meltable adhesive fiber based on 100 parts by weight of the fiber web. Is preferred. More preferably, based on 100 parts by weight of the fiber web, 50 to 97 parts by weight of the bulky cellulose fiber and 3 to 30 parts by weight of the hot-melt adhesive fiber are included.

Regarding the points which are not described in detail with respect to the fibrous web 208, the first absorbent sheet 1 described above is used.
The detailed description of the fibrous web 108 in 00 applies as appropriate.

Next, the super absorbent polymer 206 contained in the second absorbent sheet 200 of the present invention will be described. As shown in FIG. 2, the superabsorbent polymer 20
6 is contained in the inside of the 2nd absorbent sheet 200 of this invention like the super absorbent polymer 106 contained in the said 1st absorbent sheet 100, and the 2nd absorbent sheet 200 of this invention is contained. It is dispersed in the space formed between the constituent fibers. More specifically, as shown in FIG. 2, the superabsorbent polymer 206 is mainly contained inside the fibrous web 208, and is dispersed in the space formed between the fibers constituting the fibrous web 208. Preferably. As a result, the superabsorbent polymer 206 is reliably fixed in the second absorbent sheet 200 of the present invention, and gel blocking is suppressed.

The superabsorbent polymer 206 is adhered to the fibers constituting the second absorbent sheet 200 of the present invention, preferably the fibers constituting the fiber web 208. Therefore, the immobilization of the superabsorbent polymer 206 becomes stronger and the gel blocking can be further suppressed.

It should be noted that points not particularly described in detail regarding the superabsorbent polymer 206, such as the dispersion state, type, and various physical properties of the superabsorbent polymer 206, are the same as those in the first absorbent sheet 100. Absorbent polymer 10
The detailed description regarding 6 applies as appropriate.

Next, the fiber assembly 205 having the absorbent surface 202 in the second absorbent sheet 200 of the present invention will be described. The fiber assembly 205 does not include the superabsorbent polymer 206 on the absorbent surface 202 side. Here, the meaning of the “absorption surface” is the same as that of the first absorbent sheet 100. The fiber aggregate 205 has an average fiber length of 1 to 20 mm and a fiber roughness of 0.
It contains bulky cellulose fibers of 3 mg / m or more and hydrophilic fine fibers having an average fiber length of 0.02 to 0.5 mm, and the proportion of the hydrophilic fine fibers on one surface side is the other surface. Higher than the percentage present on the side. The first surface of the fiber assembly 205 is the absorption surface 20.
It corresponds to 2. On the other hand, the second surface of the fiber assembly 205 is adjacent to the fiber web 208, as shown in FIG.

As described above, the fiber assembly 205 has a gradient in the thickness direction with respect to the abundance ratio of the hydrophilic fine fibers, and the structure of the fiber assembly 205 having such a gradient is as follows. The first absorbent sheet 100
The structure is the same as that of the fiber web 108. Therefore,
For the details of the structure of the fiber aggregate 205, the description of the fiber web 108 of the first absorbent sheet 100 is appropriately applied. In addition, the fiber assembly 2
The details of the bulky cellulose fibers and hydrophilic fine fibers constituting No. 05 are also described in the first absorbent sheet 1 above.
The detailed description of the bulky cellulosic fibers and hydrophilic fine fibers in the No. 00 fiber web 108 applies as appropriate.

As described above, the second absorbent sheet 2 of the present invention
00 is the fiber aggregate 205 and the fiber web 208.
Also, the super absorbent polymer 206 is mainly formed. And, the preferable range of the basis weight of the fiber aggregate 205, the fiber web 208, and the superabsorbent polymer 206 is the same as the preferable range of the first absorbent sheet 100.
The description detailed in No. 00 is applied as appropriate. The details of the basis weight, thickness, and the like of the second absorbent sheet 200 are also the same as those of the first absorbent sheet 100, and the detailed description of the first absorbent sheet 100 is applied as appropriate.

Also in the second absorbent sheet 200 of the present invention having such a configuration, the first absorbent sheet 100 described above is also used.
Similarly, it has a liquid diffusion gradient. More specifically, the second absorbent sheet 200 has a liquid diffusion gradient from the absorbent surface 202 of the second absorbent sheet 200 toward the inside thereof (in particular, the portion of the fiber assembly 205). That is, since the absorbent surface 202 (first surface) and its vicinity are formed mainly of the bulky cellulose fibers, a bulky network structure is formed. As a result, the liquid is highly permeable from the absorption surface 202 (first surface) to the vicinity thereof, and the liquid quickly permeates into the fiber assembly 205. Since the second surface side of the fiber assembly is formed mainly of the hydrophilic fine fibers having a high surface area, the absorbent surface 202 is formed.
The liquid that has permeated from the (first surface) side can be quickly diffused over the entire surface of the second absorbent sheet. As a result, the liquid is efficiently fixed by the superabsorbent polymer 206. Thus, the second absorbent sheet 2
00 also has a liquid permeation / diffusion / fixing function in its single structure like the first absorbent sheet 100. Can be fixed.

Incidentally, the first absorbent sheet and the second absorbent sheet of the present invention
In the absorbent sheet, other layers may be further integrated as needed.

Next, the first absorbent sheet and the second absorbent sheet of the present invention
A preferred method for manufacturing the absorbent sheet will be described.

First, a preferred method for producing the first absorbent sheet of the present invention will be described. The first absorbent sheet has an average fiber length of 1 to 20 mm and a fiber roughness of 0.
It contains bulky cellulose fibers of 3 mg / m or more and hydrophilic fine fibers having an average fiber length of 0.02 to 0.5 mm, and the presence ratio of the hydrophilic fine fibers on one surface side of the other is A superabsorbent polymer is sprinkled on the surface of the wetted fibrous web, which has a higher proportion of the hydrophilic fine fibers than the proportion on the surface side, and has an average fiber length of 1 to 20 mm and a fiber roughness. It is characterized by including a step of superposing a fiber assembly mainly composed of bulky cellulose fibers of 0.3 mg / m 2 or more, and drying and integrating them.

Each of these steps will be described below.

First, bulky cellulose fibers having an average fiber length of 1 to 20 mm and a fiber roughness of 0.3 mg / m or more and hydrophilic fine fibers having an average fiber length of 0.02 to 0.5 mm are included. Forms a fiber web in which the abundance ratio of the hydrophilic fine fibers on the surface side is higher than the abundance ratio on the other surface side. The method for forming the fibrous web is not particularly limited, and for example, a dry papermaking method can be used, but a wet papermaking method is preferably used. This is because, as described below, when the superabsorbent polymer is sprinkled on the fiber web, the fiber web must be wet and the degree of freedom of the fibers must be extremely high.
This is because if the fibrous web is formed by the wet papermaking method, the wet state can be realized immediately, and therefore the time and effort required for the wet state in another step can be saved. Further, in the fiber web obtained by the wet papermaking method, the fibers are not sufficiently bonded to each other before being dried. It also has the advantage that it is easy to be three-dimensionally embedded in the space formed in, and a large amount of superabsorbent polymer can be dispersed. Further, by using the wet papermaking method, the presence of the hydrophilic fine fibers in the thickness direction of the fiber web is utilized by utilizing the difference in average fiber length between the bulky cellulose fiber and the hydrophilic fine fiber. It becomes easier to provide a gradient in proportion.

The method for forming the fiber web by the wet papermaking method will be described in detail. First, the bulky cellulose fiber and the hydrophilic fine fiber are dispersed in water to form a slurry. The slurry is supplied to the forming part 130 as shown in FIG. 3, and the slurry is sprayed on the round net 132. When the slurry is sprinkled on the round net 132, water in the slurry is removed through the round net 132, and at the same time, the wet fibrous web 108 is formed on the round net 132. As shown in FIG. 5, in the fiber web 108, the bulky cellulose fibers 12 form a bulky network structure in the thickness direction. On the other hand, since the hydrophilic fine fibers 14 in the slurry are finer than the bulky cellulose fibers, they pass through the network structure together with water and are deposited on the round net 132. As a result, the hydrophilic fine fibers have a gradient in the distribution in the thickness direction of the fiber web 108. That is, as shown in FIG. 5, of the surface of the fiber web 108, the circular net 1
The existence ratio of the hydrophilic fine fibers on the surface in contact with 32 is higher than the existence ratio on the other surface.

As described above, in the preferred method for producing the fiber web 108 using the wet papermaking method, the difference in fiber length and fiber diameter between the bulky cellulose fiber and the hydrophilic fine fiber is utilized. And the fiber web 108
There is a gradient in the abundance ratio of the hydrophilic fine fibers in the thickness direction.

The concentration of the bulky cellulose fiber in the slurry is preferably 0.02 to 1% by weight based on the total amount of the slurry, and more preferably
It is 0.03 to 0.7% by weight. If the concentration of the bulky cellulose fiber is less than 0.02% by weight, the desired permeation rate will be insufficient, or the amount of waste water for obtaining the desired basis weight will be too large, resulting in energy saving. When the concentration of the bulky cellulose fibers is more than 1% by weight, the dispersibility of the fibers is deteriorated and unevenness of the paper layer may occur. Therefore, the above range is preferable.

On the other hand, the concentration of the hydrophilic fine fibers in the slurry is preferably 0.002 to 0.5% by weight based on the total amount of the slurry, and more preferably 0.003 to 0. It is 3% by weight. If the concentration of the hydrophilic fine fibers is less than 0.002% by weight, the desired diffusivity may not be obtained, and the concentration of the hydrophilic fine fibers exceeds 0.5% by weight. And the first
Since the hydrophilic fine fibers are present also on the surface side, the desired diffusion gradient may not be obtained in some cases, so the above range is preferable.

The concentration of the heat-melting adhesive fiber optionally used for the fiber web 108 in the slurry is preferably 0.001 to 0.3% by weight, and 0.002 to 0% by weight. It is even more preferable to set it as 0.2% by weight. If the above concentration is less than 0.001% by weight,
The purpose of keeping the structure of the fibrous web 108 stable may not be achieved, and if the concentration exceeds 0.3% by weight, the hydrophilicity of the entire fibrous web 108 may decrease, so Preferably.

As described above, in the preferred method for producing the fiber web 108 using the wet papermaking method shown in FIG. 3, when the slurry is sprayed on the round net 132, the bulkiness of the bulky cellulose fiber is increased. A fine network structure is formed, the hydrophilic fine fibers pass through the space in the bulky network structure, and the circular net 1 is formed.
32 is deposited. For this purpose, it is important to make the average fine fiber length of the hydrophilic fine fibers larger than that of the mesh of the round net 132. When the average fiber length of the hydrophilic fine fibers is smaller than the mesh of the round net 132, the hydrophilic fine fibers pass through the round net 132, so in the thickness direction of the fiber web 108, It is not preferable because it becomes impossible to effectively provide a gradient in the abundance ratio of the hydrophilic fine fibers. If the mesh of the round net 132 is too small, the hydrophilic fine fibers will be clogged on the round net 132, which is not preferable. Therefore, the above-mentioned circular net 1
32 (paper making wire) has an opening diameter of 22 to 22.
It is preferably 300 μm (580 to 50 mesh), and more preferably 45 to 250 μm (330 to 60 mesh) [based on new JIS (1987)].

According to the above preferred method for producing the fibrous web 108 using the wet papermaking method, it is particularly easy to provide a gradient in the distribution of the hydrophilic fine fibers in the thickness direction of the fibrous web 108. You can The degree of such a gradient depends on the speed (water removal speed) when the fiber web 108 formed on the round net 132 is dehydrated. That is, depending on the papermaking speed and the basis weight of the fiber web,
When the dehydration rate is low, the degree of the gradient becomes small,
As a result, the hydrophilic fine fibers may be distributed almost uniformly in the thickness direction of the fiber web 108. On the other hand, when the dehydration rate is high, the degree of the gradient becomes large, which is preferable, but a large amount of energy is required to increase the dehydration rate. In consideration of these, in the present invention, the dehydration rate is preferably 2 liter / m ² · sec or more, more preferably 3 to 30 liter / m ² · sec. For dehydration, for example, as shown in FIG. 3, a suction box 136 used in an ordinary wet paper machine can be used.

According to the above-mentioned method, it is possible to manufacture a fibrous web capable of expressing liquid absorption and permeability and liquid diffusivity in one papermaking process, and it is possible to simplify the papermaking process. .

The moistened fibrous web 108 thus formed, as shown in FIG.
It is picked up by No. 4, and the inside and outside is reversed. Then, the fibrous web 108 is picked up by the conveyor 140, and the front and back are turned over again, and the superabsorbent polymer 106 is sprinkled on the fibrous web 108 while the wet state is maintained. The distribution surface of the superabsorbent polymer 106 is the surface side of the fiber web 108 in which the proportion of the hydrophilic fine fibers is low, that is, the first surface side. When using the previously manufactured dry fiber web 108,
Before the super absorbent polymer 106 is sprinkled on the fibrous web 108, water is sprinkled on the fibrous web 108 to keep it wet. The wet state of the fibrous web is preferably about 20 to 500 parts by weight of water based on 100 parts by weight of the dry fibrous web, and more preferably 50 to 30 parts.
Contains 0 parts by weight of water. If the amount of water is less than 20 parts by weight, the sprinkled superabsorbent polymer 106 absorbs water and wets, and adhesiveness cannot be obtained. When the amount of water becomes sufficient and the amount of water exceeds 500 parts by weight, the super absorbent polymer 106 described above is obtained.
May excessively absorb water, resulting in poor drying in the drying step described later. Therefore, it is preferably within the above range.

As shown in FIG. 3, the super absorbent polymer 1 is added to the fibrous web 108 in the wet state in this way.
Spray 06. As a result, the sprayed superabsorbent polymer 106 is embedded in the fibers constituting the fiber web 108, absorbs water and becomes sticky, and is adhered / fixed to the fibers. Further, since the fibers constituting the fibrous web 108 in a wet state are not yet bonded to each other and have a degree of freedom, the superabsorbent polymer 106 can be three-dimensionally dispersed. . Therefore, as compared with the conventional absorbent sheet, a larger amount of superabsorbent polymer can be stably fixed. When the superabsorbent polymer 106 is sprayed, the superabsorbent polymer 106 may be evenly sprayed on the entire surface of the wet fibrous web 108, or, if necessary, the wet fibrous web 108 in the longitudinal direction. It is also possible to disperse the fibers in a striped manner at intervals, or to intermittently disperse in a shot shape in the longitudinal direction of the wetted fibrous web 108.

Then, as shown in FIG. 3, the fiber aggregate 105 is superposed on the surface of the fiber web 108 on which the superabsorbent polymer 106 is scattered. In this case, as the fiber aggregate 105, as shown in FIG. 3, it is also possible to unwind and use a previously produced one, or one produced in parallel with the production of the fiber web 108. It can also be used. Since the fibers in the fiber web 108 still have a degree of freedom when the fiber web 108 and the fiber aggregate 105 are superposed on each other, the superabsorbent polymer 106 is contained in the fiber web. Further, the fibers in the fiber web 108 and the fibers in the fiber assembly 105 are tightly and easily entangled with each other.

Subsequently, the superposed body of the fiber web 108 and the fiber aggregate 105 is pressed into a press part 138.
After being pressed with, the fibers constituting the fiber web 108 and the fibers constituting the fiber aggregate 105 are more closely entangled with each other by drying with the dryer 142, and further, the action of hydrogen bonding and heat fusion is also exerted. In addition, the fiber web 108 and the fiber assembly 105 are integrated to obtain the first absorbent sheet 100 of the present invention. The drying temperature is 100 to 1 depending on the type of fiber used.
It is preferably in the range of 80 ° C, and more preferably in the range of 105 to 150 ° C. The fiber web 108 and the fiber assembly 10 are dried and integrated.
5 are integrated, and the fibers forming the fiber web 108 are bonded to each other to form a sheet. In addition,
The drying means is not particularly limited, and, for example, a Yankee dryer or an air through dryer can be used.

Particularly preferably, the first absorbent sheet 100 of the present invention is produced by an in-line single step using a wet paper machine. That is, as shown in FIG. 3, the fiber web 108 is formed in the forming part 130 of the wet paper machine.
To form the fiber web 1 in the suction dehydration step 136.
08 is dehydrated, the superabsorbent polymer 106 is sprayed on the first surface side of the fiber web 108 immediately before the press part 138, and the fiber assembly 105 is superposed on the superabsorbent polymer 106. Web 108
And the above fiber assembly 105 are pressed, and then these are dried by a dryer 142 to be integrated. By such a method, the first absorbent sheet 100 of the present invention can be manufactured easily at high speed.

As the wet paper machine, an ordinary paper machine can be used, and examples of such a paper machine include a Fourdrinier paper machine, a former paper machine, and a round net paper machine. As for the steps other than those described above, the steps in the ordinary papermaking method can be appropriately used.

Next, a preferable method for producing the second absorbent sheet of the present invention will be described. The second absorbent sheet has an average fiber length of 1 to 20 mm and a fiber roughness of 0.
A superabsorbent polymer is sprinkled on a wet fiber web mainly composed of bulky cellulose fibers of 3 mg / m or more, and an average fiber length of 1 to 20 mm and a fiber roughness of 0.3 mg.
/ M or more bulky cellulose fibers and an average fiber length of 0.
A fiber assembly containing hydrophilic fine fibers of 02 to 0.5 mm, in which the proportion of the hydrophilic fine fibers on one surface side is higher than the proportion on the other surface side, The method is characterized by including a step of superimposing the surface side having a high abundance of fine fibers and the fiber web so as to be adjacent to each other, and drying and integrating them.

Each of these steps will be described below.

First, a fibrous web mainly composed of bulky cellulose fibers is formed. The method for forming the fibrous web is not particularly limited, but the wet papermaking method is preferably used for the same reason as in the preferable method for producing the first absorbent sheet.

The method for producing the fibrous web will be described in more detail. The bulky cellulosic fibers and, if necessary, the hot-melt adhesive fibers and the strength aid are dispersed in water to a predetermined concentration. Make a slurry. The slurry is supplied to the gauze of the forming part 230 as shown in FIG. As a result, the fibrous web 208 is formed on the papermaking wire 234.

The fiber web 208 formed on the papermaking wire 234 is dehydrated by the suction box 236. Then, while maintaining its wet state,
The superabsorbent polymer 206 is sprinkled onto the fibrous web 208. When using a dry fiber web that has been manufactured in advance, before spraying the super absorbent polymer 206 on the fiber web 208, water is sprayed on the fiber web 208 to make it wet. deep. With respect to the wet state of the fibrous web, the detailed description of the preferable method for producing the first absorbent sheet is applied.

As described above, as shown in FIG. 4, the super absorbent polymer 2 is added to the wet fiber web 208.
Spray 06. The spraying method is the same as in the case of manufacturing the first absorbent sheet.

Next, as shown in FIG. 4, the bulky cellulose fibers and the hydrophilic fine fibers are contained on the surface of the fibrous web 208 on which the superabsorbent polymer 206 is sprinkled, and one of them is used. The fiber aggregate 205 in which the abundance ratio of the hydrophilic fine fibers on the surface side is higher than the abundance ratio on the other surface side is superposed on the fiber web 208. In the superposition, of the surfaces of the fiber assembly 205, the surface side (that is, the second surface side) where the hydrophilic fine fibers are present in a high proportion is the fiber web 208.
To be adjacent to. In this case, the fiber assembly 205
As shown in FIG. 4, the wet papermaking method utilizing the difference in average fiber length between the bulky cellulose fiber and the hydrophilic fine fiber (the first absorbent sheet 100 described above is used.
Same as the preferred method of manufacturing the fiber web 108 in FIG.
It is also possible to unwind and use the fiber assembly previously produced by the above method, or to use the one produced by using the wet papermaking method in parallel with the production of the fiber web 208. The details of the method for producing the fiber assembly 205 using the wet papermaking method utilizing the difference in average fiber length between the bulky cellulose fiber and the hydrophilic fine fiber are described above in the first absorbent property. The detailed description of the preferred method of manufacturing the fibrous web 108 in the sheet 100 is applied.

Subsequently, the superposed body of the fiber web 208 and the fiber aggregate 205 is pressed into a press part 238.
And then dried by a dryer 242, whereby the fibers forming the fiber web 208 and the fibers forming the fiber aggregate 205 are more closely entangled with each other, and further, the action of hydrogen bonding and heat fusion is also exerted. In addition, the fiber web 208 and the fiber assembly 205 are integrated to obtain the second absorbent sheet 200 of the present invention.

Particularly preferably, the second absorbent sheet 200 of the present invention is manufactured by an in-line single step using a wet paper machine, like the first absorbent sheet. That is, as shown in FIG. 4, the fiber web 208 is formed in the forming part 230 of the wet paper machine, the fiber web 208 is dehydrated in the suction dehydration step 236, and the fiber web 208 is formed on the fiber web 208 immediately before the press part 238. The superabsorbent polymer 206 is sprinkled, and the fiber aggregate 205 is formed on the superposed polymer 206 and the fiber web 208 and the fiber aggregate 20.
5 are overlapped so that they are adjacent to the second surface, and the fiber web 208 and the fiber aggregate 205 are pressed by the press part 238, and then they are guided to the dryer 242 by the conveyor 240, and the dryer 242 Dry and integrate. By such a method, the second absorbent sheet 200 of the present invention can be manufactured easily at high speed.

Regarding the points not particularly described in detail in the description of the preferred method for manufacturing the second absorbent sheet, the descriptions described in detail in the preferred method for manufacturing the first absorbent sheet apply as appropriate. In addition, for the points not particularly described in detail in the description of the preferable manufacturing method of the first absorbent sheet and the second absorbent sheet, a conventionally known paper-making method can be appropriately used.

As described above, the first absorbent sheet and the second absorbent sheet of the present invention
Although the manufacturing method of the absorbent sheet has been described based on its preferred embodiment, it goes without saying that the manufacturing method of the first absorbent sheet and the second absorbent sheet of the present invention is not limited to such a method.

Next, the first absorbent sheet and the second absorbent sheet of the present invention
An absorbent article using the absorbent sheet will be described.

The absorbent article using the first absorbent sheet of the present invention (hereinafter referred to as the first absorbent article) has a liquid-absorbable surface layer, a liquid-retaining absorbent layer and a liquid-impermeable leakproof material. In the absorbent article having a layer, the first layer is provided on the absorbent layer side of the surface layer, the absorbent layer, or the leakproof layer.
An absorbent sheet is included.

Further, the absorbent article using the second absorbent sheet of the present invention (hereinafter referred to as the second absorbent article) has a surface layer capable of absorbing liquid, a liquid retaining absorbent layer and a liquid impermeable layer. An absorbent article having a leakproof layer is characterized in that the second absorbent sheet is contained on the surface layer, the absorbent layer, or the absorbent layer side of the leakproof layer.

Hereinafter, preferred embodiments of the first absorbent article and the second absorbent article will be described with reference to the drawings.

First, a preferred embodiment of the first absorbent article of the present invention will be described with reference to FIGS. Here, FIG. 6 is a schematic view showing a cross section in the width direction of the sanitary napkin as the first preferred embodiment of the first absorbent article of the present invention. Moreover, FIGS. 7 to 11 are schematic views (corresponding to FIG. 6) showing cross sections in the width direction of a sanitary napkin as another preferred embodiment of the first absorbent article of the present invention.
It is.

First of the first absorbent article of the present invention shown in FIG.
The sanitary napkin 300 as a preferred embodiment of
It comprises a liquid-absorbable surface layer 1, a liquid-impermeable leakproof layer 3, and a liquid-retaining absorbent layer 2 interposed between the surface layer and the leakproof layer.

More specifically, the sanitary napkin 300 described above.
Is substantially vertically long, and when the sanitary napkin is worn, the surface layer 1 is located on the side in contact with the skin, and the leak preventive layer 3 is located on the side in contact with the underwear.

As will be described later, the absorbent layer 2 includes the first absorbent sheet 100, the fluff pulp 2a, the first absorbent sheet 100 and the absorbent paper 2b covering the fluff pulp 2a. The leak-proof layer 3 is the absorption layer 2
Covers the side surface and the bottom surface. The surface layer 1 covers all the surfaces of the combination of the absorption layer 2 and the leakproof layer 3.

The surface layer 1 is not particularly limited as long as it allows liquid to pass through to the absorption layer 2, but it is particularly preferable that it has a feeling close to that of underwear.
Examples of such a surface layer include, for example, thermoplastic resin woven fabrics, nonwoven fabrics, and porous films. In particular, an apertured film made of polyolefin such as low density polyethylene can be preferably used.

The leak preventive layer 3 is not particularly limited as long as it is liquid impermeable, but it is preferable that the leak preventive layer 3 has moisture permeability and has a feeling close to that of underwear. The liquid impermeable leakproof layer having moisture permeability is, for example, a thermoplastic resin to which a filler of an inorganic compound or an organic compound is added,
It can be obtained by melt-extruding from a T-die or a circular die to form a film, and then uniaxially or biaxially stretching the film.

On the side of the sanitary napkin 300 that comes into contact with the underwear, two adhesive portions 4, 4 are formed in a stripe shape in the longitudinal direction thereof, and the adhesive portions 4, 4 are peeled off before use. Paper 5
Protected by. Further, in FIG. 6, reference numeral 6
Is a joint for joining the above members. In addition, the other points which are not described in detail are the same as those of the conventional sanitary napkin.

Next, the characteristic parts of the first absorbent article of the first embodiment will be described. The sanitary napkin 300 as the first absorbent article of the first embodiment includes a liquid-retaining absorbent layer 2, which is at least a superabsorbent polymer, a bulky cellulose fiber, and a hydrophilic layer. The first absorbent sheet 100 containing the fine fibers of The first absorbent sheet 100 is composed of a fiber assembly and a fiber web, and the fiber assembly and the fiber web are integrated, and the fiber assembly is:
Mainly composed of bulky cellulose fibers having an absorbent surface and not containing the superabsorbent polymer on the absorbent surface side, and having an average fiber length of 1 to 20 mm and a fiber roughness of 0.3 mg / m or more. The web has an average fiber length of 1 to 20.
In addition to bulky cellulose fibers having a fiber roughness of 0.3 mg / m or more in mm and hydrophilic fine fibers having an average fiber length of 0.02 to 0.5 mm, the hydrophilic fine fibers on one surface side thereof Is higher than the existing ratio on the other surface side, and is adjacent to the fiber assembly on the surface side where the existing ratio of the hydrophilic fine fibers is low, the superabsorbent polymer, the absorptive It is characterized in that it is contained inside the sheet and is adhered to the fibers constituting the absorbent sheet.

By using the above absorbent sheet,
It is possible to obtain an absorbent article free of shedding of the superabsorbent polymer and gel blocking. Moreover, since such an absorbent sheet has the functions of absorbing / permeating and diffusing a liquid and holding the liquid in its single structure, it has the above-mentioned functions like a conventional liquid absorbent article. Since it is not necessary to combine members, an extremely thin liquid absorbent article can be obtained.

First of the first absorbent article of the present invention shown in FIG.
According to a preferred embodiment of the above, the liquid is absorbed by the sanitary napkin 300 through the surface layer 1. Then, the fluff pulp 2a permeates and is absorbed and retained by the superabsorbent polymer dispersed in the first absorbent sheet 100. In this case, the first absorbent sheet 100
Is preferably arranged such that the fiber assembly having the absorption surface is located on the surface layer 1 side. The first
By arranging the absorbent sheet in this manner, the liquid absorbed by the fluff pulp 2a can be more smoothly transferred to the first
A desirable effect of leading to the absorbent sheet 100 is obtained.

As described in detail in the description of the first absorbent sheet 100, the first absorbent sheet 100 can retain a large amount of superabsorbent polymer as compared with the conventional absorbent sheet. The sanitary napkin 300 including the first absorbent sheet 100 has a large liquid holding capacity. In addition, since the superabsorbent polymer is three-dimensionally dispersed on the first absorbent sheet, gel blocking does not occur, and the original absorption performance of the superabsorbent polymer can be efficiently expressed. It is possible to obtain a further improved absorption performance by using the superabsorbent polymer. Moreover, since the sanitary napkin 300 shown in FIG. 6 includes the fluff pulp 2a in addition to the first absorbent sheet 100, the liquid holding capacity is further increased. Therefore, the 1st absorbent article of this embodiment is suitable as a sanitary napkin for the night worn for a long time.

Next, FIGS. 7 to 11 show second to sixth preferred embodiments of the first absorbent article of the present invention. The same points as those of the first embodiment in the second to sixth embodiments will not be described in detail, but the detailed explanations of the first embodiment will be applied as appropriate. Also, FIG.
11, the same members as those in FIG. 6 are designated by the same reference numerals.

Second of the first absorbent article of the present invention shown in FIG.
In the sanitary napkin 100 as a preferred embodiment of 1., the absorbent layer is composed only of the first absorbent sheet 100, and the side surface portion and the bottom surface portion of the first absorbent sheet 100 are formed by the leak-proof layer 3. It is covered. The surface layer 1 covers all the surfaces of the combination of the first absorbent sheet 100 and the leakproof layer 3. In the present embodiment as well, similar to the first embodiment, the first absorbent sheet 100 is arranged such that the fiber assembly having the absorbent surface is located on the surface layer 1 side. Is preferred.

Since the sanitary napkin 300 has a small number of members constituting it and each member is thin, the sanitary napkin can be an extremely thin sanitary napkin.
Furthermore, since the first absorbent sheet 100 retains a large amount of superabsorbent polymer, it is thin,
The liquid holding capacity is large. In addition, since the superabsorbent polymer is three-dimensionally dispersed on the first absorbent sheet, gel blocking does not occur, and the original absorption performance of the superabsorbent polymer can be efficiently expressed. It is possible to obtain a further improved absorption performance by using the superabsorbent polymer. As a result, it is possible to obtain a sanitary napkin which has a comfortable fit and has a large liquid holding capacity and further improved absorption performance.

Third of the first absorbent article of the present invention shown in FIG.
In the sanitary napkin 300 as a preferred embodiment of 1., the absorbent layer is composed only of the first absorbent sheet 100, and the first absorbent sheet 100 is bent in a C shape. Then, the first absorbent sheet 1
00 has its side surface portion and bottom surface portion covered with the leak-proof layer 3. Furthermore, all the surfaces of the combination of the first absorbent sheet 100 and the leakproof layer 3 are covered with the surface layer 1
Is coated. In addition, in this embodiment, it is preferable that the first absorbent sheet 100 is bent and arranged such that the fiber assembly having the absorbent surface is located on the surface layer 1 side.

The sanitary napkin 300 has the above-mentioned first structure.
Although the absorbent sheet 100 is bent in a C shape, it is thicker than the sanitary napkin shown in FIG. 7, but is still thinner than the sanitary napkin shown in FIG. 6 using fluff pulp for the absorbent layer 2. can do. Moreover, since the first absorbent sheet 100 is bent into a C shape, the liquid holding capacity is large. As a result, a sanitary napkin having a comfortable fit and a large liquid holding capacity can be obtained.

Fourth of the first absorbent article of the present invention shown in FIG.
In the sanitary napkin 300 as a preferred embodiment of the above, the absorbent layer is the first absorbent sheet 100, 10
It is formed by stacking multiple sheets of 0, ... (Three sheets in FIG. 9). And the said 1st absorbent sheet 10 which was piled up.
The side surfaces and the bottom surface of 0, 100, ... Are covered with the leak-proof layer 3. Further, the surface layer 1 covers all the surfaces of the combination of the first absorbent sheets 100, 100, ... And the leak preventive layer 3. In the present embodiment as well, similar to the first embodiment, the first absorbent sheet 100 is arranged such that the fiber assembly having the absorbent surface is located on the surface layer 1 side. Is preferred.

The sanitary napkin 300 is the first
Although the absorbent sheets 100 are stacked one on top of the other, they are thicker than the sanitary napkin shown in FIG. 7, but
The absorbent layer 2 can be made thinner than the sanitary napkin shown in FIG. 6, which uses fluff pulp. Moreover, the first
Since a plurality of absorbent sheets 100 are stacked, the liquid holding capacity is large. As a result, a sanitary napkin having a comfortable fit and a large liquid holding capacity can be obtained.

In the sanitary napkin 300 as the fifth preferred embodiment of the first absorbent article of the present invention shown in FIG. 10, the first absorbent sheet 100 has a surface layer capable of absorbing liquid and a liquid retaining property. Also has the function of the absorbent layer (that is, the absorbent article has a liquid-retaining absorbent layer and a liquid-impermeable leak-proof layer). That is, the sanitary napkin 300 of the present embodiment has the first absorbent sheet 1 in which the liquid-absorbable surface layer and the liquid-retaining absorbent layer are integrated.
00, and the side surface portion and the bottom surface portion of the first absorbent sheet 100 are covered with the leak preventive layer 3. In the present embodiment, it is particularly preferable that the first absorbent sheet 100 is arranged so that the fiber assembly having the absorbent surface is located on the side in contact with the skin.

The sanitary napkin 300 has a reduced number of constituent members and can be made even thinner. As a result, it is possible to obtain a sanitary napkin which is comfortable to wear and can be manufactured by a simple process at low cost.

In the sanitary napkin 300 as the sixth preferred embodiment of the first absorbent article of the present invention shown in FIG. 11, the first absorbent sheet has a surface layer capable of absorbing liquid and a liquid retaining property. It has three functions of an absorption layer and a liquid-impermeable leak-proof layer. That is, the sanitary napkin 300 of the present embodiment is formed by integrating a liquid-absorbable surface layer, a liquid-retaining absorption layer, and a liquid-impermeable leak-proof layer. More specifically, the first absorbent sheet 100 and the surface of the absorbent sheet that is opposite to the surface that absorbs liquid are bonded together
It comprises an integrated liquid impermeable sheet 3 '.
In the present embodiment, the first absorbent sheet 1 described above is used.
It is particularly preferable that 00 is arranged so that the fiber assembly having the absorbing surface is located on the side that absorbs the liquid, and that the liquid impermeable sheet 3 ′ is bonded to the surface opposite to the absorbing surface. .

The sanitary napkin 300 has a reduced number of constituent members and can be made even thinner. As a result, it is possible to obtain a sanitary napkin that has a more comfortable fit and can be manufactured by a simpler process at low cost. In addition to the sanitary napkin shown in FIG. 11, the first absorbent article of the present embodiment is also suitable as an absorbent article such as a breast milk pad or a hygiene pad that absorbs a small amount of liquid.

Next, a preferred embodiment of the second absorbent article of the present invention will be described. A preferred embodiment of the second absorbent article of the present invention is the same as the first to sixth embodiments (FIGS. 6 to 11) described with respect to the first absorbent article, instead of the first absorbent sheet. The second absorbent sheet is used. That is, the first absorbent sheet 100 in the sanitary napkin 300 shown in FIGS. 6 to 11.
Instead, the absorbent article using the second absorbent sheet corresponds to the second absorbent article. Therefore, as for the details of the second absorbent article, the detailed description of the first absorbent article and the description of FIGS. 6 to 11 are appropriately applied.

Although the first absorbent article and the second absorbent article of the present invention have been described by taking the sanitary napkin as an example as a preferred embodiment, the first absorbent article and the second absorbent article are hygiene. It can be similarly applied to other absorbent articles such as pads, diapers, medical pads and breast milk pads. In addition, the constituent materials of the absorbent article, the manufacturing method, and the like can be freely modified within the range of the conventional technique as long as they do not depart from the requirements of the present invention.

[0162]

EXAMPLES Next, the present invention will be described more specifically by way of examples. First, used in Examples and Comparative Examples,
The production of bulky cellulose fibers and hydrophilic fine fibers will be described. In the following description, "parts" and "%" represent "parts by weight" and "% by weight", respectively, unless otherwise specified.

Production Example 1 Production of Bulky Cellulose Fibers The average fiber length is 2.35 mm and the fiber roughness is 0.36 m.
g / m and mercerized pulp having a roundness of fiber cross section of 0.80 [“POROSA manufactured by ITT RAYONIER INC.
NIER-J "(trade name)] 100 g, 5% dimethylol dihydroxyethylene urea [crosslinking agent," Sumitex Resin NS-19 "(trade name) manufactured by Sumitomo Chemical Co., Ltd.] and 3% metal salt Catalyst [Sumitex manufactured by Sumitomo Chemical Co., Ltd.
Accelerator X-110 "(trade name)]
The mercerized pulp was dispersed in 00 g to impregnate the crosslinking agent.

Then, after the aqueous solution of the crosslinking agent was separated from the mercerized pulp until the amount of the aqueous solution of the crosslinking agent with respect to the mercerized pulp was 200%, the mixture was heated at 135 ° C. for 10 minutes in an electric dryer, The cellulose in the mercerized pulp was crosslinked to obtain a mercerized crosslinked pulp. This is designated as cellulose fiber (A).

Production Example 2 Production of Bulky Cellulose Fibers The average fiber length is 2.38 mm and the fiber roughness is 0.32 m.
g / m and roundness of fiber cross section of 0.30 [High Bulk Add manufactured by Weyerhauser Paper
itive HBA-S ”(trade name)] was prepared. This is designated as cellulose fiber (B).

Production Example 3 Production of Bulky Cellulose Fibers The average fiber length is 2.56 mm and the fiber roughness is 0.24 m.
A softwood kraft pulp [“HARMAC-R” (trade name) manufactured by MacMillan Bloedel Ltd.) having a circularity of 0.34 was prepared. This is designated as cellulose fiber (C). The cellulose fiber (C) is not crosslinked.

The average fiber length, the fiber roughness and the roundness of the fiber cross section of each of the cellulose fibers (A) to (C) were measured by the following methods. Table 1 shows the results.

<Measurement of Average Fiber Length and Fiber Roughness> It was measured using a fiber roughness meter FS-200 (manufactured by KAJAANI ELECTRONICS LTD.). First, in order to determine the true weight of the cellulose fiber, the cellulose fiber is dried in a vacuum dryer at 100 ° C.
And dried for 1 hour to remove water present in the cellulose fiber. Accurately weigh approximately 1 g of cellulosic fibers to an accuracy of ± 0.1 mg. Next, the cellulose fiber is completely disaggregated in 150 ml of water with a mixer attached to the fiber roughness meter so as not to damage the cellulose fiber,
This was diluted with water to 5000 ml, 50 ml was accurately measured from the obtained diluted solution, and this was used as a fiber roughness measuring solution, and the average fiber length and fiber roughness were obtained according to the operation procedure of the fiber roughness meter. It was As the average fiber length, a value calculated by the following formula based on the above operation was used.

[0169]

(Equation 1)

<Measurement of Roundness of Fiber Cross Section> To measure the roundness of the cellulose fiber cross section, first, the cellulose fiber is sliced perpendicularly to the cross section direction so that the area of the cross section of the cellulose fiber does not change, and the A cross-section photograph was taken with a microscope, and the cross-section photograph was analyzed by an image analyzer [“Avio EXCEL” (trade name) manufactured by Nippon Avionics Co., Ltd.), and the roundness of the cellulose fiber cross section was obtained using the formula shown below. . The roundness was an average value obtained by measuring 100 cross sections of an arbitrary cellulose fiber.

[0171]

(Equation 2)

[0172]

[Table 1]

[Production Example 4] Production of hydrophilic fine fibers Cellulose fine fibers having an average fiber length of 0.12 mm obtained by acid hydrolysis of selected pulp, washing with water and drying, and mechanical pulverization [Sanyo Kokusaku "KC Flock W-100" (trade name) manufactured by Pulp Co., Ltd. was prepared. This is a hydrophilic fine fiber (D).

Example 1 Production of Absorbent Sheet Cellulose fiber (A) concentration was 0.16%, hydrophilic fine fiber (D) concentration was 0.03%, and average fiber diameter was 1 denier. Make the concentration of polyvinyl alcohol fiber (heat-melting adhesive fiber, hereinafter referred to as PVA, Fibribond (trade name) manufactured by Sansho Co., Ltd.) having a length of 3 mm of 0.01% (the entire slurry is 0. 20%), and these were uniformly dispersed in water to obtain a slurry.

The wire opening diameter of this slurry was 90 μm.
(166 mesh) on a wire mesh paper wire,
A paper layer was formed on the wire netting wire. Suction
6 liters / m^Two・ This paper at the speed of sec
Layers are dehydrated, basis weight 70g / m ^TwoTo be fiber web
Was formed.

This fiber web contains 80 parts of the above cellulose fibers (A), 15 parts of the above hydrophilic fine fibers (D), and 5 parts of the above PVA fibers based on 100 parts of the above fiber web, and As shown in FIG. 5, the proportion of the hydrophilic fine fibers (D) present on one side is high, and the proportion of the hydrophilic fine fibers (D) present on the other side is low. The liquid diffusion is greater on the side where the ratio of the hydrophilic fine fibers (D) is higher, and on the opposite side, the liquid diffusion is smaller, which has a diffusion gradient.

Then, the fiber web was put in a suction box to obtain a moisture content of 200 based on 100 parts of the dry fiber web.
Of the hydrophilic fine fibers (D) on the surface of the wet moistened fiber web after dehydration by press until a high absorption polymer [Nippon Catalyst ( Co., Ltd., Aqualic CAW-4 (trade name)] was sprayed almost uniformly at a spray basis weight of 50 g / m ² .

Among the above-mentioned fiber webs, a fiber aggregate having a basis weight of 30 g / m ² prepared in advance with the following composition was superposed on the surface on which the superabsorbent polymer was sprayed, and the fiber web and the fiber aggregate were obtained. The superposed product of and was introduced into a dryer, and dried and integrated at a temperature of 130 ° C. to obtain a single absorbent sheet having a superabsorbent polymer fixed therein. This is designated as an absorbent sheet (A).

The fiber assembly preliminarily made from paper was produced by the following method. That is, the concentration of the cellulose fiber (A) is
These were uniformly dispersed in water so that the concentration of the PVA fiber was 0.194% and the concentration of the PVA fiber was 0.006% (0.20% as a whole of the slurry) to obtain a slurry. This slurry was sprayed on a wire mesh paper making wire having a wire opening diameter of 90 μm (166 mesh) to form a paper layer on the wire mesh making wire. Using a suction box, this paper layer was dehydrated and dried at a rate of 6 liter / m ² · sec to produce a fiber assembly having a basis weight of 30 g / m ² . This fiber assembly contained 97 parts of the cellulose fiber (A) and 3 parts of the PVA fiber based on 100 parts of the fiber assembly.

Example 2 Production of Absorbent Sheet First, as a fiber web, the concentration of the cellulose fiber (B) was 0.194%, and the concentration of the PVA fiber was 0.
006% (0.20 as a whole slurry)
%), And these were uniformly dispersed in water to obtain a slurry. This slurry was used for wire opening diameter 90 μm (16
(6 mesh) was sprinkled onto a wire mesh paper making wire to form a paper layer on the wire mesh paper making wire. Using a suction box, this paper layer was dehydrated at a rate of 6 liter / m ² · sec to form a fiber web having a basis weight of 30 g / m ² . This fiber web is based on 100 parts of the fiber web, and 97 parts of the cellulose fiber (B) and the PVA.
It contained 3 parts of fiber.

Then, the fiber web was subjected to a suction box to obtain a water content of 200 based on 100 parts of the dry fiber web.
Dehydrated until part.

Immediately before the press part, a superabsorbent polymer [AQUARIC CAW-4 (trade name) manufactured by Nippon Shokubai Co., Ltd.] was sprayed onto the wetted fibrous web after dewatering at a basis weight of 50 g / m 2. Sprayed almost evenly with ² .

Among the above-mentioned fiber webs, a fiber aggregate having a basis weight of 70 g / m ² , which had been previously paper-made with the following composition, was superposed on the surface on which the above-mentioned superabsorbent polymer was dispersed, and the fiber web and the fiber aggregates were obtained. The superposed product of and was introduced into a dryer, and dried and integrated at a temperature of 130 ° C. to obtain a single absorbent sheet having a superabsorbent polymer fixed therein. This is designated as an absorbent sheet (B).

The fiber assembly preliminarily made from paper was produced by the following method. That is, the concentration of the cellulose fibers (A) is 0.16%, the concentration of the hydrophilic fine fibers (D) is 0.03%, and the concentration of the PVA fibers is 0.01% (slurry. 0.20% as a whole), these were uniformly dispersed in water to obtain a slurry.

[0185] The wire opening diameter of this slurry was 90μ.
m (166 mesh) on the wire mesh paper wire,
A wire layer was formed on the wire netting wire. Using a suction box, this paper layer was dehydrated and dried at a speed of 6 liter / m ² · sec to form a fiber assembly having a basis weight of 70 g / m ² .

In this fiber assembly, 80 parts of the cellulose fiber (A), 15 parts of the hydrophilic fine fiber (D), and 5 parts of the PVA fiber based on 100 parts of the fiber assembly were used.
Part was included. As shown in FIG. 5, this fiber assembly has a high proportion of the hydrophilic fine fibers (D) present on the side adjacent to the wire netting wire and the hydrophilic fine fibers (D) on the other side. The existence ratio of is low. The liquid diffusion is greater on the side where the ratio of the hydrophilic fine fibers (D) is higher, and on the opposite side, the liquid diffusion is smaller, which has a diffusion gradient.

Example 3 Production of Absorbent Sheet From the formulation shown in Table 2, an absorbent sheet was obtained by the same operation as in Example 1. This is designated as an absorbent sheet (C).

Comparative Example 1 Production of Absorbent Sheet A fibrous web having a basis weight of 70 g / m ² was previously made into paper with the following composition. That is, the concentration of the cellulose fiber (C) is 0.1
6%, the concentration of the hydrophilic fine fibers (D) is 0.03
%, And the concentration of the PVA fiber was 0.01% (0.20% as a whole of the slurry), these were uniformly dispersed in water to obtain a slurry.

The wire opening diameter of this slurry was 90 μm.
It was sprinkled on the wire mesh paper making wire (166 mesh) to form a paper layer on the wire mesh paper making wire. Using a suction box, this paper layer was dehydrated and dried at a speed of 6 liter / m ² · sec, and paper was made to have a basis weight of 70 g / m ² . This fiber web contained 80 parts of the cellulose fiber (C), 15 parts of the hydrophilic fine fiber (D), and 5 parts of the PVA fiber based on 100 parts of the fiber web. The above-mentioned cellulose fiber (C) blended in this fiber web has a fiber roughness of less than 0.3 mg / m and therefore cannot have a bulky network structure.
The hydrophilic fine fibers (D) are the cellulose fibers (C)
Since it cannot pass through the inside, the hydrophilic fine fibers (D) are blended almost uniformly in the thickness direction and do not have a liquid diffusion gradient.

Then, water was sprinkled on the basis of 100 parts of the fiber web (dry) to 200 parts, and then the superabsorbent polymer [Nippon Shokubai Co., Ltd.] was placed on the wet fiber web.
Made by Aqualic CAW-4 (trade name)]
/ M ² and sprayed almost uniformly.

Among the above-mentioned fiber webs, a fiber aggregate having a basis weight of 30 g / m ² prepared in advance with the following composition was superposed on the surface on which the superabsorbent polymer was dispersed, and the fiber web and the fiber aggregates were obtained. After stacking and stacking with, and drying them with a dryer, the total basis weight is 150 g / m ²
The absorbent sheet of was obtained. This is designated as an absorbent sheet (D). In the absorbent sheet (D), the fibrous web on which the superabsorbent polymer is dispersed is not in a wet fibrous state, but the fibers forming the fibrous web are strongly bound to each other. Moreover, the absorbent sheet (D) is a layered sandwich of the superabsorbent polymer between the fiber web and the fiber assembly.

The fiber assembly preliminarily made from paper was produced by the following method. That is, the cellulose fibers (C) are uniformly dispersed in water so that the concentration of the cellulose fibers (C) is 0.19% and the concentration of the PVA fibers is 0.01% (0.20% as a whole of the slurry). Got

[0193] This slurry was used as a wire opening diameter of 90μ.
m (166 mesh) on the wire mesh paper wire,
A paper layer was formed on the wire netting wire. Using a suction box, the paper layer was dehydrated and dried at a rate of 6 liter / m ² · sec to form a fiber assembly having a basis weight of 30 g / m ² .

This fiber assembly had 95 parts of the above-mentioned cellulose fiber (C) based on 100 parts of the fiber assembly, and
It contained 5 parts of A fiber.

Comparative Example 2 Production of Absorbent Sheet A superabsorbent polymer [Nippon Shokubai Co., Ltd.] was used between pulp sheets having a basis weight of 45 g / m ² formed by the air laid method.
Made by Aqualic CAW-4 (trade name)] with a basis weight of 50 g / m
^It was sprinkled so that it would be ² , and then pulp was fixed with a chemical binder to produce an absorbent sheet. This absorbent sheet is referred to as an absorbent sheet (E).

Comparative Example 3 Production of Absorbent Sheet A dry absorbent sheet containing synthetic pulp and a superabsorbent polymer was produced. That is, polyethylene synthetic pulp 25
Sheet and a pulp sheet consisting of 75 parts of chemical pulp are defibrated with a hammer mill to form a dry absorbent sheet having a basis weight of 100 g / m ^2, a superabsorbent polymer [Nippon Shokubai Co., Ltd., Aqualic CAW-4 (product name)] 50 g /
The raw material was mixed so as to have m ² and then polyethylene synthetic pulp was fused and integrated by hot air treatment. The dry absorbent sheet has a total basis weight of 150 g / m ² , and the superabsorbent polymer is present on the surface thereof. This absorbent sheet is referred to as an absorbent sheet (F).
The chemical pulp is a general cellulose fiber (softwood kraft pulp) that is neither bulky nor fine.

Absorbent sheet (A) in Examples 1 to 3
~ (C) and the absorbent sheet (D) in Comparative Examples 1 to 3 ~
The compounding composition of (F) and the manufacturing method are shown in Tables 2 and 3.

[0198]

[Table 2]

[0199]

[Table 3]

Absorbent sheet (A) in Examples 1 to 3
~ (C) and the absorbent sheet (D) in Comparative Examples 1 to 3 ~
Regarding (F), in order to evaluate the immobilization ability and the absorption performance of the superabsorbent polymer, the thickness, the dropout test of the superabsorbent polymer, the saturated absorption amount, the absorption rate, and the liquid return amount were measured by the following methods. . The respective results are shown in Table 4.

<Thickness> A load of 2.5 g / cm ² was applied to the upper surface of the absorbent sheet cut into an appropriate size, and the thickness thereof was measured. The average value of a total of 10 points was taken as the thickness.

<Detachment test of superabsorbent polymer> 70 × 2
After measuring the weight of the absorbent sheet cut out to 00 mm,
This is put into a plastic bag with a chuck having a length of 280 mm and a width of 200 mm, and in this state, it is shaken 50 times by hand to vibrate. After the test, the weight change of the absorbent sheet was measured, and the colored water dyed with Blue No. 1 (0.3
(100 g of water / 100 ml of water) is added to a plastic bag to swell the superabsorbent polymer, and the degree of dropout is visually determined. ○: Almost no dropout of the superabsorbent polymer was observed. Δ: Some dropout of the superabsorbent polymer is observed. X: The dropout of the superabsorbent polymer is considerably observed. The measurement was performed 10 times, and the average value was used as the amount of dropout.

<Saturated absorption amount> A 5 cm square absorbent sheet was placed in a bag made of non-woven fabric, and the entire bag was immersed in ion-exchanged water for 10 minutes. After removing the bag from the ion-exchanged water, it was hung in the air for 1 hour to remove the adhering water, and then the weight was measured, and the increase in the weight per 1 g of the absorbent sheet was measured as the saturated absorption amount (g / g). ).

<Absorption rate> As shown in FIG.
A 10 cm square transparent acrylic plate 20 and a weight 22 having a hole with a diameter of 1 cm are placed in the center of the corner absorbent sheet 100, and the absorbent sheet 100 is loaded with a load of 5 g / cm ² to form the above holes. 20 ml of physiological saline was injected through the solution, and the time required for absorption of physiological saline was defined as the absorption rate. The absorption rate was measured twice, but the second injection (resorption rate) was performed 1 minute after the first measurement.

<Measurement of Liquid Return Amount> After measuring the absorption rate, 1
As shown in FIG. 14, ten 15 cm square filter papers 24 (Toyo Filter Paper TYPE2) are stacked on the absorbent sheet 100 after 0 minutes, and a 15 cm square acrylic plate 26 and a weight 2 are further stacked thereon.
2 was applied for 1 minute so that the load was 50 g / cm ² , and then the filter paper 24 was taken out, and the weight of the physiological saline absorbed by the filter paper 24 was taken as the liquid return amount.

[0206]

[Table 4]

Example 4 Production of Absorbent Article A sanitary napkin having the constitution shown in FIG. 8 was produced . That is, as the absorbent sheet 100, the absorbent sheet (A) having a length of 175 mm and a width of 145 mm was folded and compressed in a C shape so that both side edges of the absorbent sheet (A) face each other substantially at the center of the absorbent body to have a width of 73 mm. This absorbent sheet (A) was used as an absorber.
Poly-laminate waterproof paper (length 205 mm, width 95 as the leak-proof layer 3
mm) was used to cover the side and bottom of the obtained absorbent sheet. A liquid-absorbable surface layer 1 (205 mm in length, 172 in width 172) to be described later on all surfaces of the combination of the absorbent sheet and the poly-laminate waterproof paper.
mm) and these members were fixed by the hot melt adhesive used as fixative 6. Further, ^two hot-melt pressure-sensitive adhesives having a basis weight of 30 g / m ² , a width of 20 mm and a length of 115 mm were coated as a pressure-sensitive adhesive portion 4 on the opposite surface side of the surface material 1. In this way, a sanitary napkin having the structure shown in FIG. 8 was obtained. As the surface layer 1, a polyethylene perforated film was used. This surface layer 1 has a basis weight of 30.
A polyethylene film of g / m ² is perforated, and one perforation diameter is 0.5 mm and the perforation area ratio is 20.
% Perforated.

[Examples 5 and 6] Production of absorbent article Example 4 except that absorbent sheets (B) and (C) were used instead of the absorbent sheet (A) used in Example 4, respectively. In the same manner as described above, a sanitary napkin having the structure shown in FIG. 8 was obtained.

Comparative Example 4 Production of Absorbent Article A sanitary napkin having the constitution shown in FIG. 15 was produced . That is,
Length 1 adjusted to a thickness of 4.5 mm at a basis weight of 300 g / m ^2.
After spraying a small amount of water on the flap pulp 2a having a width of 75 mm and a width of 73 mm, the superabsorbent polymer 2e [AQUARIC CAW-4 (trade name) manufactured by Nippon Shokubai Co., Ltd.] is 60 m wide.
About 0.53 g was sprayed almost uniformly over an area of m and a length of 175 mm to give a spray basis weight of 50 g / m ² . On top of this, a wet absorbent paper 2b made of wood pulp having a basis weight of 18 g / m ² and a length of 175 mm and a width of 73 mm was superposed, and all the surfaces of these combinations were covered with a basis weight of 18 g / m ² and a length of 175 mm. Width 130
An absorbent layer 2 was prepared by coating with a wet absorbent paper 2c made of wood pulp having a size of mm to form an integrated absorbent layer 2. After that, in the same manner as in Example 3, a sanitary napkin having the configuration shown in FIG. 15 was produced.

Preparation of Absorbent Articles [Comparative Examples 5 to 7] Absorbent sheet (A) used in Example 4
A sanitary napkin having the configuration shown in FIG. 8 was obtained in the same manner as in Example 4 except that the absorbent sheets (D) to (F) were used instead of.

For evaluating sanitary napkins in Examples 4 to 6 and Comparative Examples 4 to 7, the polymer immobilization ability and the absorption ability were evaluated by the methods described below, the polymer dropout test, the product thickness, the absorption time, and the dynamic liquid. A return amount and leak test were performed on each sanitary napkin. The respective results are shown in Table 5 below.

<Detachment Test of Super Absorbent Polymer> Example 4
6 to 6 and Comparative Examples 4 to 7, the weight of the sanitary napkins is measured, and then the sanitary napkins are put into a plastic bag with a chuck having a length of 280 mm and a width of 200 mm, and in this state, vibration is applied while shaking by hand 50 times. After the test, the weight change of the sanitary napkin was measured, and the colored water dyed with Blue No. 1 (0.3 g / 100 ml of water) was used so that the superabsorbent polymer that had fallen into the plastic bag could be observed with the naked eye. Into a plastic bag, swell the superabsorbent polymer, and visually determine the degree of shedding. ○: Almost no dropout of the superabsorbent polymer was observed. Δ: Some dropout of the superabsorbent polymer is observed. X: The dropout of the superabsorbent polymer is considerably observed. The measurement is performed 10 times, and the average value is used as the amount of dropout.

<Measurement of product thickness> As shown in FIG.
Ten sanitary napkins were overlaid, an acrylic plate weighing 500 g was placed on the sanitary napkin, and the thickness of the ten napkins was measured to determine the product thickness per sheet.

<Absorption time (5 g), re-absorption time (10
g), Measurement of dynamic liquid return amount> An absorption rate measuring device shown in FIG. 13 was used. That is, the absorbent sheet 1 shown in FIG.
Instead of 00, the sanitary napkins obtained in Examples 4 to 6 and Comparative Examples 4 to 7 were placed horizontally, an acrylic plate 20 with an inlet having a diameter of 1 cm was placed, and a weight 22 was placed thereon. A load of 5 g / cm ² was applied to the sanitary napkin. Next, 5 g of defibrinated horse blood (manufactured by Japan Biotest Institute Co., Ltd.) is injected from the injection port, and the absorption time (second) until the defibrinated horse blood is completely absorbed is determined. After the defibrinated horse blood was completely absorbed, it was left as it was for 20 minutes, 5 g of defibrinated horse blood was injected again, the reabsorption time (10 g) was determined, and it was left for 20 minutes in the same manner. After that, basis weight 30g / m
² length 195 mm, 10 sheets of absorbent paper made of softwood kraft pulp having a width 75 mm, placed on the top surface of the sanitary napkin (skin contact surface side), a movable female waist model 90 shown in FIG. 17
Then, as shown in FIG. 18, shorts with a sanitary napkin 80 were put on and then walked for 1 minute at a walking speed of 100 seconds / minute (50 m / minute). After walking, the sanitary napkin 80 and 10 sheets of absorbent paper were taken out, and the weight of defibrinated horse blood absorbed in the absorbent paper was determined as the liquid return amount (g).
The measurement was carried out at 5 points respectively, and the respective average values were obtained, which were taken as the absorption time, re-absorption time and dynamic liquid return amount.

<Leak Test (Number of Leak Occurrences)> Examples 4 to
6 and the sanitary napkin 80 obtained in Comparative Examples 4 to 7,
As shown in FIG. 18, after putting on the movable female waist model 90 and putting on the shorts, 100 steps / min (50 m / min.
Minutes) at a walking speed of 10 minutes. Then, while walking, 5 g of defibrinated horse blood was injected into the sanitary napkin 80 through the tube 91, and then walking at the same speed for 20 minutes (5 g absorption), and further defibrinated horse blood 5
After injecting g, walking at the same speed for 20 minutes (1
(0 g absorption), and the number of leaks was counted out of 10 samples at each time point.

[0216]

[Table 5]

As is clear from the results shown in Tables 4 and 5, the absorbent article of the present invention which uses a specific absorbent sheet is a conventional absorbent sheet (such as water spraying, embossing integration or integration with an adhesive). Compared with the absorbent article having the absorbent sheet obtained in 1.), even if an extremely thin absorbent sheet having a thickness of 1 mm or less is superior in the fixability of the superabsorbent polymer, the absorption rate, the amount of liquid return, etc. It can be seen that the absorption characteristics of are excellent. In addition, the absorbent article of the present invention has a very simple structure, but has a very high absorption time of liquid, a small amount of liquid return, and a small number of leaks, and is of extremely high performance. . This is because the absorbent sheet used in the absorbent article of the present invention has a liquid absorption / diffusion gradient in its single structure, so that it quickly absorbs liquid and smoothly moves through the absorbent sheet. This is because the liquid permeates and the liquid sufficiently diffuses.

[0218]

As described above in detail, according to the present invention, the superabsorbent polymer is reliably fixed in the sheet, the superabsorbent polymer is hardly detached, and gel blocking of the superabsorbent polymer occurs. A difficult absorbent sheet is obtained. The absorbent sheet has three functions of permeation / diffusion / holding of liquid in a single structure, and is excellent in both absorption rate and absorption power.

Further, according to the preferable method for manufacturing the absorbent sheet of the present invention, the manufacturing process is significantly accelerated as compared with the conventional method for manufacturing the absorbent sheet. In addition, a complicated processing process for fixing the superabsorbent polymer is not required, which greatly simplifies the manufacturing process.

Further, according to the above-mentioned manufacturing method, not only the superabsorbent polymer can be sprinkled all over the absorbent sheet, but it can also be partially sprinkled in the longitudinal direction or intermittently sprinkled in the longitudinal direction. Therefore, the range in which the superabsorbent polymer is sprayed can be set according to the application, and the absorbent sheet can be manufactured more economically.

Further, according to the present invention, it is possible to provide an extremely thin absorbent article on which a large amount of superabsorbent polymer is fixed, although it is extremely thin. In addition, the absorbent article has a high liquid absorption rate, a small liquid return amount, and a small number of leaks. In particular, when the absorbent layer is composed of only the absorbent sheet, the absorbent article can be manufactured by cutting only one absorbent sheet, and the absorbent article can be manufactured at a high speed with an extremely simple manufacturing process. Can be produced. In addition, since the absorbent sheet has an integrated structure, the superabsorbent polymer absorbs the absorbent article even if the absorbent article equipped with the absorbent sheet is subjected to vigorous exercise. It does not separate from the sheet and the absorption performance does not deteriorate.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a cross section of a first absorbent sheet of the present invention.

FIG. 2 is a schematic view showing a cross section of a second absorbent sheet of the present invention.

FIG. 3 is a schematic view showing an apparatus preferably used for producing the first absorbent sheet of the present invention.

FIG. 4 is a schematic view showing an apparatus preferably used for producing the second absorbent sheet of the present invention.

FIG. 5 is a schematic view showing a cross section of a fiber web formed on a papermaking wire.

FIG. 6 is a schematic view showing a cross section of a sanitary napkin as a first embodiment of the first absorbent article of the present invention.

FIG. 7 is a schematic view showing a cross section of a sanitary napkin as a second embodiment of the first absorbent article of the present invention.

FIG. 8 is a schematic view showing a cross section of a sanitary napkin as a third embodiment of the first absorbent article of the present invention.

FIG. 9 is a schematic view showing a cross section of a sanitary napkin as a fourth embodiment of the first absorbent article of the present invention.

FIG. 10 is a schematic view showing a cross section of a sanitary napkin as a fifth embodiment of the first absorbent article of the present invention.

FIG. 11 is a schematic view showing a cross section of a sanitary napkin as a sixth embodiment of the first absorbent article of the present invention.

FIG. 12 is a schematic view showing a cross section of a conventional absorbent sheet.

FIG. 13 is a schematic diagram showing measurement of absorption time.

FIG. 14 is a schematic diagram illustrating measurement of a liquid return amount.

FIG. 15 is a schematic view showing a cross section of a conventional sanitary napkin.

FIG. 16 is a schematic diagram showing measurement of the thickness of a sanitary napkin.

FIG. 17 is a diagram showing a movable female waist model.

FIG. 18 is a schematic diagram showing a state in which a sanitary napkin is attached to the crotch part of a movable female waist model.

[Explanation of symbols]

 100 1st absorptive sheet 200 2nd absorptive sheet 300 1st absorptive article 102,202 Absorption surface 105,205 Fiber assembly 106,206 Superabsorbent polymer 107,207 Transmission layer 108,208 Fiber web 109,209 Diffusion layer

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location D04H 13/00 A61F 13/18 307E (72) Minoru Nakanishi Minoru Nakanishi 2606 Kao, Kaiga-cho, Haga-gun, Tochigi Prefecture Stock company research institute

Claims (12)

[Claims] 1. An absorbent sheet comprising at least a superabsorbent polymer, bulky cellulose fibers and hydrophilic fine fibers, said absorbent sheet comprising a fiber aggregate and a fiber web, and The fiber assembly and the fiber web are integrated, the fiber assembly has an absorbent surface, does not contain the superabsorbent polymer on the absorbent surface side, and has an average fiber length of 1 to 20 mm and a fiber coarseness. Is mainly composed of bulky cellulose fibers having a degree of 0.3 mg / m or more, and the fiber web has bulky cellulose fibers having an average fiber length of 1 to 20 mm and a fiber roughness of 0.3 mg / m or more and an average fiber length of 0. 0.02 to 0.5 mm of hydrophilic fine fibers, the proportion of the hydrophilic fine fibers on one surface side is higher than the proportion on the other surface side, and the parent Adjacent to the fiber assembly on the surface side where the presence ratio of the aqueous fine fibers is low, the superabsorbent polymer is contained in the absorbent sheet and the fibers constituting the absorbent sheet. An absorbent sheet characterized by being adhered. 2. An absorbent sheet comprising at least a superabsorbent polymer, bulky cellulose fibers and hydrophilic fine fibers, wherein the absorbent sheet is composed of a fiber aggregate and a fiber web, and The fiber assembly and the fiber web are integrated, the fiber assembly has an absorbent surface, does not contain the superabsorbent polymer on the absorbent surface side, and has an average fiber length of 1 to 20 mm and a fiber coarseness. In addition to containing bulky cellulose fibers having a degree of 0.3 mg / m or more and hydrophilic fine fibers having an average fiber length of 0.02 to 0.5 mm, the proportion of the hydrophilic fine fibers present on one surface side is It is higher than the existing ratio on the other surface side, and the fiber web is mainly composed of bulky cellulose fibers having an average fiber length of 1 to 20 mm and a fiber roughness of 0.3 mg / m or more, and the above fiber aggregate. It is adjacent to the fiber assembly on the surface side where the abundance ratio of the hydrophilic fine fibers in the body is high, and the superabsorbent polymer is contained inside the absorbent sheet and the absorbent sheet is An absorbent sheet characterized by being adhered to constituent fibers. 3. The absorbent sheet according to claim 1, wherein the superabsorbent polymer is contained in the fibrous web. 4. The blending ratio of the bulky cellulose fiber and the hydrophilic fine fiber in the fiber web is
The absorbent sheet according to claim 1, wherein the bulky cellulose fibers are 50 to 97 parts by weight and the hydrophilic fine fibers are 3 to 50 parts by weight based on 100 parts by weight of the fiber web. 5. The blending ratio of the bulky cellulose fiber and the hydrophilic fine fiber in the fiber assembly is
The absorbent sheet according to claim 2, wherein the bulky cellulose fibers are 50 to 97 parts by weight and the hydrophilic fine fibers are 3 to 50 parts by weight based on 100 parts by weight of the fiber aggregate. 6. The absorbent sheet according to claim 1, wherein the bulkiness of the cellulose fiber has a roundness of a fiber cross section of 0.5 to 1. 7. The absorbent sheet according to claim 1, 2 or 6, wherein the bulky cellulose fibers are crosslinked cellulose fibers. 8. The method for producing an absorbent sheet according to claim 1, wherein the bulky cellulose fibers having an average fiber length of 1 to 20 mm and a fiber roughness of 0.3 mg / m or more and an average fiber length of 0.02. ~
The hydrophilicity in a wet fibrous web containing 0.5 mm of hydrophilic fine fibers in which the proportion of the hydrophilic fine fibers on one surface side is higher than the proportion on the other surface side. The super absorbent polymer is sprinkled on the surface having a low proportion of fine fibers, and the average fiber length is 1 to 20 mm and the fiber roughness is 0.3 mg.
A method for producing an absorbent sheet, which comprises a step of superposing fiber aggregates mainly composed of bulky cellulose fibers having a bulkiness of not less than 1 / m, and then drying and integrating them. 9. The method for producing an absorbent sheet according to claim 2, wherein the wetted fiber is mainly composed of bulky cellulose fibers having an average fiber length of 1 to 20 mm and a fiber roughness of 0.3 mg / m or more. The super absorbent polymer is sprinkled on the web, and the average fiber length is 1 to 20 mm and the fiber roughness is 0.3 m.
It contains bulky cellulose fibers of g / m or more and hydrophilic fine fibers having an average fiber length of 0.02 to 0.5 mm, and the existence ratio of the hydrophilic fine fibers on one surface side of the other is A fiber aggregate having a higher abundance ratio on the surface side is superposed so that the abundance ratio of the hydrophilic fine fibers is higher and the fiber web is adjacent to each other, and a step of drying and integrating them is performed. A method for producing an absorbent sheet, comprising: 10. The fiber web is formed in a forming part, the fiber web is dehydrated in a suction dehydration step, the superabsorbent polymer is sprinkled on the fiber web immediately before the press part, and the fiber aggregate is formed thereon. 10. The method according to claim 8 or 9, comprising the step of superimposing the bodies and then drying and integrating them with a dryer. 11. An absorbent article having a liquid-absorbable surface layer, a liquid-retaining absorbent layer, and a liquid-impermeable leakproof layer, wherein the surface layer or the absorbent layer or the leakproof layer is the absorbent layer. The side includes at least a superabsorbent polymer, a bulky cellulose fiber and an absorbent sheet containing hydrophilic fine fibers, and the absorbent sheet is composed of a fiber aggregate and a fiber web, The fiber assembly and the fiber web are integrated, and the fiber assembly has an absorption surface, does not include the superabsorbent polymer on the absorption surface side, and has an average fiber length of 1 to 20 mm. Mainly composed of bulky cellulose fibers having a roughness of 0.3 mg / m or more, and the above fiber web has bulky cellulose fibers having an average fiber length of 1 to 20 mm and a fiber roughness of 0.3 mg / m or more. Including hydrophilic fine fibers having an average fiber length of 0.02 to 0.5 mm, the proportion of the hydrophilic fine fibers on one surface side is higher than the proportion on the other surface side, and the hydrophilicity Is adjacent to the fiber assembly on the surface side where the abundance ratio of the hydrophilic fine fibers is low, and the superabsorbent polymer is contained in the inside of the absorbent sheet and the fibers constituting the absorbent sheet. An absorbent article characterized by being adhered. 12. An absorbent article having a liquid-absorbable surface layer, a liquid-retaining absorbent layer, and a liquid-impermeable leak-proof layer, wherein the surface layer or the absorbent layer or the leak-proof layer is the absorbent layer. The side includes at least a superabsorbent polymer, a bulky cellulose fiber and an absorbent sheet containing hydrophilic fine fibers, and the absorbent sheet is composed of a fiber aggregate and a fiber web, The fiber assembly and the fiber web are integrated, and the fiber assembly has an absorption surface, does not include the superabsorbent polymer on the absorption surface side, and has an average fiber length of 1 to 20 mm. A bulky cellulose fiber having a roughness of 0.3 mg / m or more and a hydrophilic fine fiber having an average fiber length of 0.02 to 0.5 mm are included, and the presence ratio of the hydrophilic fine fiber on one surface side thereof. Is higher than the existing ratio on the other surface side, the fiber web is mainly composed of bulky cellulose fibers having an average fiber length of 1 to 20 mm and a fiber roughness of 0.3 mg / m or more, and in the above fiber assembly. It is adjacent to the fiber assembly on the surface side where the hydrophilic fine fibers are present in a high proportion, and the superabsorbent polymer is contained inside the absorbent sheet and constitutes the absorbent sheet. An absorbent article characterized by being adhered to fibers.