JPH0833677A - Absorbent article - Google Patents

Abstract

(57) [Abstract] [Purpose] Excellent moisture permeability, excellent initial adhesiveness and adhesive coating suitability, and the softener component in the adhesive or moisture permeable sheet seeps out on the surface of the moisture permeable sheet. There is little phenomenon of becoming transparent, and a sticky feeling occurs on the surface of the moisture-permeable sheet,
The appearance of absorbent articles such as diapers may be impaired, various characteristics may be adversely affected, blocking of absorbent articles such as diapers may occur during storage, and adhesive properties may change over time due to changes in the adhesive composition. To provide an absorbent article with various adverse effects, such as erosion. In an absorbent article including a moisture-permeable sheet coated with an adhesive, the moisture-permeable sheet has polypropylene as a main component and a component that is liquid at room temperature, and has a moisture permeability of 0. 5g / 100cm ² · h ~ 4g / 100cm
^{2. The} absorbent article, which has a hardness of ² · h and a reduction rate of reflectance of a portion to which an adhesive is applied when stored at 50 ° C. for 3 days is 20% or less.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to absorbent articles such as disposable diapers using a moisture permeable sheet, and more specifically, compounds used as a constituent of an adhesive or contained in the moisture permeable sheet. That is, at a temperature above the melting point of the crystalline polyolefin used for the moisture-permeable sheet, the crystalline polyolefin is miscible and melts, but at a temperature below the melting point of the crystalline polyolefin, the crystalline polyolefin has a phase The present invention relates to an absorbent article in which a compound that causes separation (hereinafter, referred to as "softening agent") exudes and a phenomenon in which a contact portion between the moisture permeable sheet and the adhesive is transparent is small.

[0002]

2. Description of the Related Art Generally, an absorbent article has a liquid permeable sheet (surface material), a liquid impermeable sheet (back material), and a predetermined portion of an absorbent body interposed between the sheets. Is bonded and fixed with an adhesive or the like.

[0003] Among absorbent articles, particularly in a paper diaper, a moisture-permeable sheet having moisture permeability is used as the liquid impermeable sheet to prevent swelling and rashes. On the other hand, in order to bond the liquid impermeable sheet, usually for improving initial adhesiveness and improving coating suitability,
Adhesives with increased proportions of softening agents are mainly used.

However, when the above-mentioned adhesive is used for the moisture-permeable sheet, the softening agent component of the adhesive migrates into the sheet to cause the phenomenon of transparency, resulting in a sticky feeling on the surface of the moisture-permeable sheet, a diaper, etc. There are various adverse effects such as adverse effects on various properties of the absorbent article, blocking of absorbent articles such as diapers during storage, and changes in adhesive properties over time due to changes in adhesive composition. There is a problem that it will occur.

As the moisture permeable sheet, a moisture permeable sheet containing a softening agent component is used in order to exhibit moisture permeability and softness. The moisture permeable sheet containing such a softening agent component is used. When the above-mentioned adhesive is used for the sheet, there is a problem that the above-mentioned transparency phenomenon is further promoted.

Therefore, in order to solve the above problems, an adhesive for adhering the moisture-permeable sheet is disclosed in Japanese Patent Laid-Open No. 7759/1992.
No. 1 and Japanese Patent Laid-Open No. 4-84960.

The above-mentioned Japanese Patent Laid-Open No. 4-77591 discloses α-
Olefin resin, styrene-ethylene-propylene-
A styrene block copolymer as a main component, a tackifier, and a hot melt adhesive containing a plasticizing oil have been proposed, and by using the adhesive, when a moisture-permeable sheet and a nonwoven fabric are bonded, It has been reported that there is no exudation of low molecular weight substances, the tack force disappears after cooling and solidification, and stickiness disappears.

However, in the above-mentioned publication, the moisture permeability of the moisture permeable sheet is not stipulated, and the exudation property (transparency) of the part to which the adhesive is applied is not stipulated. . Further, in this adhesive, when a moisture-permeable sheet comprising a crystalline polyolefin and a softening agent is used as the moisture-permeable sheet, the moisture-permeable sheet is transparent due to migration of the softening agent from the moisture-permeable sheet. There is also a problem that it becomes easy to make it.

Further, the above-mentioned JP-A-4-84960 proposes an adhesive which comprises a styrene block polymer, a tackifier resin and a softening agent and which regulates the activation energy of the styrene phase and the rubber phase. Furthermore, it reports on an absorbent article having a low degree of transparency, which is obtained by adhering a moisture-permeable sheet having a specified moisture permeability using the adhesive.

However, the above publication does not specify the specific composition of the adhesive, and in this adhesive as well, a moisture permeable sheet comprising a crystalline polyolefin and a softening agent is used as the moisture permeable sheet. In this case, there is also a problem that the moisture permeable sheet easily becomes transparent due to migration of the softening agent from the moisture permeable sheet.

Therefore, the object of the present invention is to provide excellent moisture permeability,
In addition, it has excellent initial adhesiveness and suitability for application of adhesive, and there is little phenomenon that the softener component in the adhesive or the moisture permeable sheet seeps out to the moisture permeable sheet surface and becomes transparent, and the surface of the moisture permeable sheet becomes sticky. Feeling, the appearance of absorbent articles such as diapers is impaired, various properties are adversely affected, blocking of absorbent articles such as diapers occurs during storage, and adhesive properties change due to changes in the adhesive composition. An object of the present invention is to provide an absorbent article which has various adverse effects such as changes over time.

[0012]

Means for Solving the Problems As a result of various studies to solve the above-mentioned problems, the present inventors have found that a specific component is a main component and a specific moisture permeability and an adhesive are applied. It has been found that an absorbent article provided with a moisture permeable sheet having the above-mentioned reduction rate of reflectance can achieve the above object.

The present invention has been made on the basis of the above findings, and in an absorbent article provided with a moisture-permeable sheet coated with an adhesive, the moisture-permeable sheet is mainly composed of a crystalline polyolefin. , At a temperature equal to or higher than the melting point of the crystalline polyolefin, the compound is miscible and soluble in the crystalline polyolefin, but at a temperature equal to or lower than the melting point of the crystalline polyolefin, a compound that causes phase separation with respect to the crystalline polyolefin Then, by dissolving and mixing these, a solution comprising the crystalline polyolefin and the compound is obtained, a sheet is formed from the solution, and then the sheet is stretched in at least one direction to form fine pores. A porous sheet having a moisture permeability of 0.
A ^{5g / 100cm 2 · h~4g / 100cm} 2 · h,
The load when stretching 3% in the width direction of the sheet is 100 g /
cm to 300 g / cm, bulk softness of 55 g or less, breaking strength of 250 g / cm or more, and 5
It is intended to provide an absorbent article characterized in that the rate of decrease in reflectance of the portion coated with the adhesive when stored at 0 ° C. for 1 day is 20% or less.

Hereinafter, the absorbent article of the present invention will be described in detail. The moisture-permeable sheet provided in the absorbent article of the present invention,
Containing a specific component as a main component, it has a specific moisture permeability, a load at the time of 3% extension in the width direction of a specific sheet, a specific bulk softness, a specific breaking strength, and a specific reflectance reduction rate. It is a breathable sheet.

The above-mentioned specific component used as the above-mentioned main component is a crystalline polyolefin, and at a temperature above the melting point of the crystalline polyolefin, the crystalline polyolefin is miscible and soluble, but the crystalline polyolefin is soluble. A compound which causes a phase separation with respect to the crystalline polyolefin at a temperature below the melting point of the compound (hereinafter referred to as "softening agent A").
Is.

By using a moisture-permeable sheet which contains the above-mentioned crystalline polyolefin and the softening agent A as main components and has a moisture-permeable amount within a specific moisture-permeable amount which will be described later, the sheet itself has strength while having moisture permeability. Is large, for example, when the moisture permeable sheet is used as the back material of the diaper, the fastening tape of the diaper can be directly attached to the moisture permeable sheet and peeled off. Further, the moisture-permeable sheet may be formed of only the main component, but other additives which are usually used in other moisture-permeable sheets may be added, and when the other additive is used, The content of the main component in the moisture permeable sheet is preferably 80 to 100% by weight.

Examples of the crystalline polyolefin include polypropylene. Specifically, polypropylene alone, polypropylene-olefin copolymer alone, a mixture of polypropylene and polypropylene-olefin copolymer, a mixture of polypropylene and polyethylene,
Alternatively, a mixture of polypropylene-olefin copolymer and polyethylene may be used. In particular, the polypropylene is crystalline polypropylene, and the relationship between the isotactic pendant fraction (P) and the melt flow rate (MFR) in the crystalline polypropylene is 1.00 ≧ P ≧ 0.015LogMFR + 0. .9
Crystalline polypropylene and the like within the range of 55 are preferable. Here, the isotactic pendant fraction (P) is an index representing the crystallinity of polypropylene, and the MFR is 0.03 to 2.0 g / 1.
It is preferably in the range of 0 minutes.

The softening agent A is miscible and melts with the crystalline polyolefin at a temperature above the melting point of the crystalline polyolefin, but at a temperature below the melting point with respect to the crystalline polyolefin. It is not particularly limited as long as it is a compound that causes phase separation by way of example, and specifically, for example, mineral oil, synthetic lubricating oil, dioctyl phthalate, diethyl phthalate, triethylene glycol, and dibutyl phthalate, phthalic acid, trimellitate. Examples thereof include esters of acids, pyromellitic acid and / or fatty acid polybasic carboxylic acids with alkyl alcohols.

The above specific moisture permeability is 0.5 g /
^{100cm 2 · h~4g / 100cm 2 ·} h, preferably ^{1.0g / 100cm 2 · h~2.5g / 100cm} 2 · h
This makes it possible to prevent leakage during use of absorbent articles such as diapers while maintaining leakproofness.

The load at the time of 3% elongation in the width direction of the above-mentioned specific sheet is 100 g / cm to 300 g / cm, preferably 100 g / cm to 200 g / cm. If the load is less than 100 g / cm, the backing sheet tends to overextend when a load is applied to the fastening tape during diaper wearing, and the fastening tape cannot follow the extension of the backing sheet, so the fastening tape may come off, The stretched part is torn. When it exceeds 300 g / cm, the back sheet is difficult to stretch, so that it is not possible to follow the movement of the wearer's body and the wearing feeling is poor.

Also, the above specific bulk softness is
It is 55 g or less, more preferably 45 g or less, and most preferably 30 to 40 g. The above bulk softness is 55g
If it exceeds, the back sheet has poor flexibility, and the entire diaper feels stiff and feels bad.

The above specific breaking strength is 250 g.
/ Cm or more, preferably 300 to 1000 g / cm.
If the breaking strength is less than 250 g / cm, the back sheet will be broken when the fastening tape is peeled off after the diaper is attached.

The above physical properties are obtained as follows. 1. Load measuring device for 3% extension of back sheet Tensilon universal tester / tensile test mode (manufactured by Orientec Co.) Sample As shown in FIG.
Sampling at different locations (at this time, if adhesive, backing paper, etc. adheres to the back sheet, wipe it off with an organic solvent such as toluene so that it does not affect the back sheet). At this time, the size of each sampled sample is 10 mm.
X (25 mm + 50 mm + 25 mm) [see FIG. 1]. Measurement conditions (1) Measurement environment: temperature 20 ° C, humidity 65
% RH (2) Tensile condition: Distance between chucks 50 mm Tensile speed 300 mm / min Measurement result 3% elongation (when the distance between chucks 50 mm became 51.5 mm) was measured for tensile strength for each of five samples, Calculate the average.

2. Bulk softness measuring device Tensilon universal testing device / compression test mode (manufactured by Orientec Co.) Sample (1) For sampling location, see 1. It is the same as the sampling location under the load when the back sheet is stretched by 3%, but the dimensions of the sample are
The size is 30 mm × 150 mm. (2) Measurement sample: As shown in FIG. 2 (a), using each sampled sample, a cylinder a having a surface (outer surface side of the diaper) of 45 mm in diameter as the outside is formed, and the upper and lower ends of the overlapped portion are formed. Staple and stop. Then
The ring b made of vinyl chloride shown in FIG. 2 (b) is applied to the lower part of the cylinder a: a measurement sample c shown in FIG. 2 (c). Measurement conditions (1) Measurement environment: temperature 20 ° C, humidity 65
% RH (2) Compression condition: compression speed 10 mm / min Measurement result The maximum strength when the sample was compressed by 20 mm was measured for each of the five samples, and the average thereof was calculated to obtain the bulk softness.

3. Breaking strength A test was conducted in the same manner as in "1. Measurement of load when the backsheet is stretched by 3%", the load at the time of breaking was determined, and the load was defined as the breaking strength.

Further, the above-mentioned specific reduction rate of reflectance is 20% when the adhesive is applied to the moisture-permeable sheet and stored at 50 ° C. for 1 day. %
Below, it is preferably 0 to 15%. Here, the method of measuring the reflectance will be described in the method of measuring transparency described below, and the “rate of decrease in reflectance” is obtained by the following formula. 100− (reflectance after storage at 50 ° C. for 1 day ÷ initial reflectance) × 100

If the rate of decrease in reflectance exceeds 20%, the portion to which the adhesive has been applied becomes apparently transparent, resulting in an unsightly appearance and a sticky feeling, and further, there is a problem in that the adhesive strength is reduced.

The moisture permeable sheet used in the present invention is a porous sheet obtained by using the above main components as follows. The crystalline polyolefin and the softening agent A are melt-kneaded to form a solution of the crystalline polyolefin and the softening agent A, and then a sheet of the solution is formed. A moisture-permeable sheet formed by forming fine pores by stretching in the direction. Here, the crystalline polyolefin and the softener A
The mixing ratio of the crystalline polyolefin is 30 to 8
It is preferable that the amount of the softening agent A is 0 parts by weight and the amount of the softening agent A is 70 to 20 parts by weight.

In the present invention, the adhesive applied to the moisture permeable sheet includes a base polymer, a tackifier resin that is solid at room temperature, and a component that is liquid at room temperature (hereinafter referred to as "softener component"). Adhesives and the like constituted by using as a constituent can be preferably mentioned.

Examples of the softener component used as a constituent component of the adhesive include process oils having a softening point of 10 ° C. or lower and an average molecular weight of 200 to 700, mineral oils, various plasticizers, polybutene, and liquid adhesive liquid resins. Specific examples thereof include paraffin oils such as "Shelf Rex" (trade name, manufactured by Shell Chemical Co., Ltd.) and "PW-90" (trade name, manufactured by Idemitsu Kosan Co., Ltd.), tetraoctylpyromellitate, gidodecyl phthalate, and tritium. Examples thereof include ester oils such as octyl trimellitate.

The blending amount (content) of the softening agent component is preferably 20% by weight or less, more preferably 0 to 14% by weight, based on the whole adhesive. If the blending amount of the above-mentioned softening agent component exceeds 20% by weight, the above-mentioned transparency phenomenon may become remarkable, so it is preferable to set it within the above range.

The base polymer used as a constituent of the adhesive is natural rubber, isoprene rubber, styrene-butadiene rubber, styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene. Block copolymer (SI
S), styrene rubber such as styrene / ethylene / butylene / styrene block copolymer (SEBS), styrene / ethylene / propylene / styrene block copolymer (SEPS), and amorphous poly-α-olefin (APA)
O), olefin polymers such as EVA, and the like.

The tackifier resin which is solid at room temperature and is used as a constituent component of the adhesive is C5.
-Based petroleum resin, C9-based petroleum resin, dicyclopentadiene-based petroleum resin, rosin-based petroleum resin, polyterpene resin, terpene-phenolic resin, etc., and specifically, "Clearon" (trade name, manufactured by Yasuhara Chemical Co., Ltd.), etc. And hydrogenated aromatic petroleum resins such as "Arcon" (trade name, manufactured by Arakawa Chemical Industry Co., Ltd.).

The compounding amount (content) of the tackifier can be appropriately selected according to the compounding amount of the softening agent component. That is, when the blending amount of the softening agent component is 20% by weight or less with respect to the entire adhesive, the blending amount of the tackifier is not particularly limited, but is usually 30% with respect to the entire adhesive. To 70% by weight is appropriately selected. Further, the softening agent component is 20% by weight with respect to the adhesive component.
It is possible to use up to 30% by weight,
In this case, the compounding amount of the tackifier is 30% by weight or less, preferably 10% by weight or less, and more preferably 5 to 10% by weight based on the whole adhesive. When the compounding amount of the above tackifier exceeds 10% by weight and the above softening agent component exceeds 20% by weight, problems such as transparency of the part to which the adhesive is applied and a decrease in adhesive strength may occur. Therefore, the above range is preferable.

Further, in the present invention, the adhesive is
A blended product within the above blending ratio and blending range can be preferably used.
An adhesive having a melt viscosity at 80 ° C. of preferably 10,000 CPS or less, more preferably 1000 to 8000 CPS is preferable. When the melt viscosity is more than 10,000 CPS, the coatability is deteriorated and the coated surface becomes uneven,
The adhesive may drop off, which is not preferable.

Further, the above-mentioned adhesive preferably contains an inorganic filler in an amount of 5% by weight or less, preferably 0.5 to 3% by weight, based on the entire adhesive. It is possible to reduce the rate of decrease of 5% by about 5%. That is, even an adhesive having a reflectance reduction rate of 25% can be reduced to 20% or less by containing an inorganic filler. If the content of the inorganic filler exceeds 5%, the adhesive becomes whiter than the moisture-permeable sheet, the coating pattern becomes clear, and the appearance becomes worse.
Further, it may cause a decrease in the adhesive force, so that the above range is preferable. Examples of the inorganic filler include titanium oxide, zinc white, silica, calcium carbonate, aluminum hydroxide, barium sulfate, starch and talc.

The above-mentioned adhesive having the above-mentioned preferable blending type and blending ratio is composed mainly of polypropylene and the above-mentioned softening agent A.
A moisture-permeable sheet made of is also applicable, and it is possible to prevent a decrease in adhesive strength over time due to the transfer of the softening agent from the sheet to the adhesive, and it is also possible to prevent transparency, so that it is particularly preferably used in the present invention.

Further, the above adhesive is used as an antioxidant.
"Irganox 1010" [trade name, manufactured by Ciba-Geigy Co., Ltd.], "Irganox 1076" [product name, manufactured by Ciba-Geigy Co., Ltd.], or "Sumilyzer GM"
[Product name, manufactured by Sumitomo Chemical Co., Ltd.] and the like can also be added and used. The amount of the antioxidant used is preferably 1 to 3 parts by weight based on 100 parts by weight of the base polymer.

In the present invention, the transparency can be measured, for example, by the method described below. here,
When the adhesive is applied and stored at 50 ° C, the seeping-out component such as a softening agent wets the surface of the moisture-permeable sheet and causes see-through (clearing). This is the same phenomenon as that when the frosted glass is wet with water, light is transmitted and the outside can be seen through the frosted glass.

Method for measuring transparency: As shown in FIG. 3, a black plate 4 is placed on the back surface of the sample 3 having a moisture-permeable sheet coated with an adhesive, and a transparent glass plate 5 is placed on the surface of the sample 3. The sample 4 is placed and the wavelength 4
While irradiating blue incident light of 59 nm,
Clarification can be quantified by measuring the reflectance of the reflected light from.

According to this method, when the amount of strike-through is large (the amount of seepage is large), blue incident light is transmitted through the sample 3 and absorbed by the black plate 4, and reflected from the sample 3. When the light reflectance decreases and the strike-through degree is small (the see-through degree is small), blue incident light rarely passes through the sample 3 and reaches the black plate 4, and the black plate 4 Sample 3 without being absorbed by
And the reflectance of the reflected light from the sample 3 becomes high. That is, when the reflectance when stored at 50 ° C. for 1 day significantly decreases compared to the initial reflectance (the rate of decrease in reflectance increases), the above-mentioned “strikethrough” often occurs during storage. Will be there.

Further, the adhesive strength of the adhesive is preferably 30% or more in terms of rubber removal retention rate, and is 50 to 10
It is more preferably 0%. The rubber retention rate is 3
If it is less than 0%, the rubber will come off during use of the diaper, the function as a gather will be lost, and leakage will occur, which is not preferable. That is, in the present invention, among the adhesives having the above-mentioned preferable blending types and blending ratios, the adhesive having the above-mentioned adhesive strength is preferably used.

Here, the "rubber loss retention rate" is obtained according to the following measuring method. (Measurement method of rubber loss retention rate) First, as shown in FIG. 4 (a), between the moisture permeable sheet and the liquid permeable sheet, made of polyurethane, the thickness is 1120d, and the stress at 100% strain is 40 g. A thread rubber (for example, manufactured by Toray DuPont,
The product name "Operon" etc.) is stretched 1.8 times and adhered. The adhesive is 2 cm on both left and right sides with the central part opened 10 cm.
Intermittent coating of the adhesive (diagonal area in the figure) at 0 cm intervals (coating basis weight 25 g / m ² ) and after applying the adhesive until the moisture-permeable sheet and the liquid-permeable sheet are bonded together The time (open time) is set to 2 seconds. After gluing
The tension is released to a natural length, and the natural length is stored at 50 ° C. for 7 days. After the storage, after returning to room temperature, as shown in FIG. 4 (b), a 30 cm sample was prepared so that the portion not coated with the adhesive becomes the central portion and includes the portion coated with the adhesive. Cut out and make a mark x on the side of the liquid permeable sheet in the central portion having a length of 10 cm.

Thereafter, as shown in FIG. 4 (c), the rubber thread is stretched and left in this stretched state for 1 hour. At this time, measure the distance between each mark x (both left and right), and set this to L
_Set to ₀ . After leaving, as shown in FIG. 4 (d),
Even if the stretched state is maintained, the recovery force of the rubber causes the portion with the mark x to move inward. At this time, the distance between the marks x is measured, and this is designated as L ₁ . And FIG.
The expansion ratio of the rubber in the state shown in (c) is calculated by the following formula, and the rubber loss retention rate (%) is calculated by the following formula. Stretching magnification = L _0/10 Rubber omission retention _{= (L 1 -10) / (} L 0 -10) × 1
00 (%)

The coating basis weight of the adhesive is 40 g /
It is preferably m ² or less, more preferably 15 to 35 g / m ² . If the coating basis weight exceeds 40 g / m ² , the coated portion becomes hard and the elasticity of the rubber decreases, and the texture deteriorates, which is not preferable.

The absorbent article of the present invention comprises a liquid-permeable surface material, an absorber for absorbing and retaining body fluids, etc., and a leak-proof backing material, wherein the backing material comprises the moisture-permeable sheet and Preferable examples include disposable diapers and sanitary napkins, which use the above adhesive when bonding the back surface material (moisture permeable sheet) to other members. Further, as the surface material and the material of the absorber, and the structure of each part and the whole, the same as those conventionally known can be applied without particular limitation. Further, since the present invention is particularly preferably applied to a disposable diaper, the disposable diaper as the absorbent article of the present invention will be described with reference to FIGS. 5 and 6.

A disposable diaper 1 suitable as the absorbent article of the present invention shown in FIGS. 5 and 6 is a surface sheet 2 made of a liquid permeable sheet, a liquid impermeable back sheet 3 made of the moisture permeable sheet, and An absorbent body 4 interposed between the two sheets 2 and 3, and these predetermined portions, specifically, substantially the entire surface of the top sheet 2 and the absorbent body 4, the substantially entire surface of the back sheet 3 and the absorbent body 4, and the like. Is bonded and fixed with the above-mentioned adhesive, and there is no reinforcing tape (target tape) used in a normal disposable diaper.

More specifically, in the disposable diaper 1 of this embodiment, as shown in FIGS. 5 and 6, the absorbent body 4 is curved and formed in the shape of an hourglass in which the crotch region is entangled. The crotch region of the seat 3 is also curved in accordance with the shape of the absorber 4 as described above, and the absorber 4 is sandwiched and fixed by the topsheet 2 and the backsheet 3. Further, the waist portions 5, 5 ′ and the leg portions 6 on the front and rear sides of the peripheral portion of the absorbent body 4 allow the wearer to fit the waist portions 5, 5 ′ and the leg portions 6 when the diaper is worn. An elastic elastic member 7 is provided by being fixed by the top sheet 2 and the back sheet 3. In the disposable diaper 1, the surface sheet 1, the absorber 4, and the overall structure are the same as those of the conventional disposable diaper.

The disposable diaper 1 is provided with a fastening tape 10, and the fastening tape 10 has a 180 ° peeling force to the back sheet 3 (moisture permeable sheet) (adhesive to the back sheet). , 2 at 40 ℃ 80% RH
The peeling force after 4 hours) is 400 g / cm or less, and the holding time under a load of 500 g is 10 minutes or more, so that it can be applied to any part of the back sheet 3 (to the entire surface). It is configured to be removable.

[0050]

The present invention will be described in detail below with reference to examples, but the present invention is not limited thereto.

Examples 1 to 9 The base polymer, tackifier resin, softening agent component, inorganic filler and antioxidant shown in [Table 1] were blended in the blending ratios shown in [Table 1], and then, Adhesives were obtained by melt-kneading at about 180 ° C. for 40 minutes. The melt viscosity of the obtained adhesive was measured by the following measuring method. The results are shown in [Table 1].

Melt viscosity measuring method: The temperature of the adhesive is set to 18
The temperature was set to 0 ° C. and measured using a B-type viscometer (manufactured by Tokyo Keiki Co., Ltd.).

Next, the above adhesive was solidly coated on release paper at 180 ° C. by a hot melt method so as to have a thickness of 30 ± 5 μ, and then a moisture permeability of 1.4 g / 100 cm ² · h of polypropylene / The propylene-ethylene block copolymer / softening agent-based moisture-permeable sheet was transfer-coated, and the initial reflectance and the reflectance after storage at 50 ° C. for 1 day were measured by the reflectance measuring method described above. The decrease rate of reflectance was obtained. In addition, the adhesiveness and the rubber loss retention rate were also tested by the following methods. The results are shown in [Table 2].

The moisture permeable sheet is a moisture permeable sheet obtained by molding the following materials using the following methods. That is, the moisture-permeable sheet is a biaxial kneading extruder to obtain a film by an air-cooled inflation molding machine using kneaded pellets of a composition composed of polypropylene and a softening agent (and various additives as required), and further roll-stretched. It was obtained by uniaxially stretching the film 1.5 times in the molding direction by a machine. The polypropylene was dry blended with 70 parts by weight of polypropylene (trade name, "WT6048" manufactured by Chisso Petrochemical) and 30 parts by weight of propylene-ethylene block copolymer (trade name, "WT6052" manufactured by Chisso Petrochemical). And liquid paraffin (manufactured by Idemitsu Petrochemical, trade name, "PW90") was used as a softening agent. The composition ratio of polypropylene and the softening agent is 7: 3 by weight. The thickness of the resulting moisture permeable sheet was about 40μ.

Adhesion measuring method: 18 on the moisture-permeable sheet
The adhesive is coated with a spiral spray at 0 ° C (coating basis weight: 15 g / m ² , coating width: 13 mm), and a nonwoven fabric used as a surface material for absorbent articles such as diapers is open time. (Time from coating to pasting) Adhesion was made in 2 seconds. After this was stored at 20 ° C. and 50 ° C. for 1 day, respectively, the moisture permeable sheet and the nonwoven fabric were peeled off, and when the material of the nonwoven fabric was destroyed, it was marked with ◯, and when the interface was peeled, it was marked with x.

Rubber retention rate: The above adhesive was spray coated on the moisture permeable sheet by a hot melt method (180 ° C.) (coating basis weight: 25 g / m ² , coating width: 25 m).
m), and 1120 denier thread rubber stretched 1.8 times (trade name “Operon” manufactured by Toray DuPont),
A non-woven fabric used as a surface material of absorbent articles such as diapers was adhered for 2 seconds in open time (time from coating to pasting). This was stored at 50 ° C. for 7 days in a state where it was returned to its natural length (shearing state), and then, according to the above-mentioned “method for measuring retention rate of rubber loss”,
The rubber loss retention rate was calculated.

[Examples 10 to 12] 66 parts by weight of polypropylene (manufactured by Mitsui Petrochemical Co., Ltd., trade name, "B200"), a crystal nucleating agent masterbatch (manufactured by EC Chemical Co., Ltd., trade name,
A moisture permeable sheet consisting of 4 parts by weight of “EC-1”, 2 wt%) and 30 parts by weight of liquid paraffin (manufactured by Idemitsu Petrochemical, trade name, “PW90”) was obtained by the same method as in Example 1. The thickness of the resulting moisture permeable sheet was about 40μ. An adhesive was applied to this sheet in the same manner as in Example 1, and the reflectance reduction rate, adhesiveness measurement, and rubber loss retention rate were measured. The results are shown in [Table 3]. As the adhesive, the adhesive used in Examples 1, 3 and 8 was used.

[0058]

[Table 1]

[0059]

[Table 2]

[0060]

[Table 3]

[0061]

The absorbent article of the present invention has excellent moisture permeability,
Moreover, the initial adhesiveness and the coating suitability of the adhesive are excellent, and the softening agent component in the adhesive or the moisture-permeable sheet does not seep into the surface of the moisture-permeable sheet and become transparent, and the surface of the moisture-permeable sheet is not sticky. Feeling, the appearance of absorbent articles such as diapers is impaired, various properties are adversely affected, blocking of absorbent articles such as diapers occurs during storage, and adhesive properties change due to changes in the adhesive composition. It has few adverse effects such as changes over time.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing sampling locations and sample dimensions when measuring a load at 3% elongation.

FIG. 2 is a schematic view showing an aspect of forming a measurement sample when measuring bulk softness.

FIG. 3 is an explanatory diagram of a measurement principle showing a measurement principle of a degree of “strikethrough phenomenon”.

FIG. 4 is a schematic diagram showing an outline of a measuring method of “rubber loss retention rate”.

FIG. 5 is a perspective view showing a front side (abdominal side) of a diaper in an example of a disposable diaper suitable as the absorbent article of the present invention.

6 is an exploded view of the disposable diaper shown in FIG.

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Claims (10)

[Claims] 1. An absorbent article provided with a moisture-permeable sheet coated with an adhesive, wherein the moisture-permeable sheet has a crystalline polyolefin as a main component, and a temperature higher than a melting point of the crystalline polyolefin. Although it is miscible and soluble in the crystalline polyolefin, it is composed of a compound that causes phase separation in the crystalline polyolefin at a temperature equal to or lower than the melting point of the crystalline polyolefin. A porous sheet obtained by obtaining a solution containing a polyolefin and the compound, forming a sheet from the solution, and then stretching the sheet in at least one direction to form fine pores. Is 0.5g / 100cm ² · h ~ 4g / 10
0 cm ² · h, the load at 3% elongation in the width direction of the sheet is 100 g / cm to 300 g / cm, the bulk softness is 55 g or less, and the breaking strength is 250 g / cm.
Absorbent article characterized in that the reduction rate of the reflectance of the part coated with the adhesive when stored at 50 ° C. for 1 day is 20% or less. 2. The absorbent article according to claim 1, wherein the adhesive has an adhesive force of 30% or more in terms of a rubber loss retention rate. 3. The coating basis weight of the adhesive is 40 g / m ^2.
The absorbent article according to claim 1, wherein: 4. The absorbent article comprises a surface sheet made of a liquid permeable sheet, a liquid impermeable back sheet made of the moisture permeable sheet, and an absorbent body interposed between the two sheets. A disposable diaper configured by adhering and fixing parts to each other with the adhesive, wherein the disposable diaper is provided with a fastening tape, and the fastening tape can be attached to and removed from any part of the backsheet. The disposable diaper which is the absorbent article according to claim 1, wherein the disposable diaper is an absorbent article. 5. The absorbent article according to claim 1, wherein the crystalline polyolefin is polypropylene. 6. The polypropylene is polypropylene alone, polypropylene-olefin copolymer alone, a mixture of polypropylene and polypropylene-olefin copolymer, a mixture of polypropylene and polyethylene, or a mixture of polypropylene-olefin copolymer and polyethylene. Claim 1 to
5. The absorbent article according to any one of 5. 7. The disposable diaper according to claim 4, wherein the adhesive contains, as its constituent components, a component that is liquid at room temperature in an amount of 20% by weight or less. 8. The disposable diaper according to claim 4, wherein the adhesive contains, as a constituent component thereof, a tackifier resin which is solid at room temperature in an amount of 10% by weight or less. 9. The disposable diaper according to claim 4, wherein the adhesive has a melt viscosity at 180 ° C. of 10,000 cps or less. 10. The adhesive has, as its constituent components,
The disposable diaper according to claim 4, which contains an inorganic filler in an amount of 5% by weight or less.