JPH1147588A - Liquid absorbing agent, absorptive article and their manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a liquid-absorbing agent which is excellent in blood absorption amount and blood gel absorption amount by a method wherein a liquid absorbing agent having a specific blood gel absorption amount is prepared with water absorptive resin of a specific blood suction amount and that which contains a specific amount of water thereto. SOLUTION: Liquid absorbing agent which is excellent in absorbing characteristics to blood is prepared so that a blood gel absorption amount becomes 3 g/g or over, and such the liquid absorbing agent is prepared with water absorptive resin of 5 g/g or over blood absorption amount and by containing 20 to 900 wt.% or over of water to the water absorptive resin. Then, though an absorptive article is prepared by using the liquid absorbing agent of 20 to 10000 g/m<2> basis weight, if only that generates expansion in volume by absorbing water as the water absorptive resin to be used, which is not especially limited, and can be generally obtained by polymerizing water-soluble unsaturated monomer. Further, an average particle size of water absorptive resin is not limited, and especially preferable 20 to 100 μm. Then, by crosslinking treatment near a surface of the water absorptive resin, a blood suction amount of the water absorptive resin and its blood absorption amount are raised.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a liquid absorbing agent, an absorbent article, and a method for producing the same. In particular, the present invention relates to a liquid absorbing agent, an absorbent article, and a method for producing the same, which have excellent blood absorption properties.

[0002]

2. Description of the Related Art In recent years, water-absorbent resins have been widely used as one of the constituent materials of sanitary materials such as disposable diapers and sanitary napkins for the purpose of absorbing body fluids. Examples of the water-absorbing resin include a crosslinked product of a partially neutralized polyacrylic acid, a hydrolyzate of a starch-acrylonitrile graft polymer, a neutralized product of a starch-acrylic acid graft polymer, and vinyl acetate-acrylate. A saponified polymer, a hydrolyzate of an acrylonitrile copolymer or an acrylamide copolymer, a crosslinked product thereof, a crosslinked product of a cationic monomer, and the like are known.

[0003] When the liquid to be absorbed is blood or the like, there are special circumstances such as a decrease in the amount of water-absorbing resin sucked because blood components surround individual water-absorbing resin particles during blood absorption and hinder absorption. Therefore, even if the water-absorbing resin has a high suction amount for urine, the suction amount for blood is not always high. In view of such circumstances, various proposals have been made as an attempt to improve the blood absorption characteristics of the water absorbent resin. For example, it has been proposed to add a compound such as salt or polyethylene glycol to a water-absorbing resin for the purpose of improving the absorbency of the water-absorbing resin against blood (Japanese Patent Laid-Open No. 58-501).
No. 107, JP-A-54-70694). Also, an attempt to improve the blood absorption rate of a nonwoven fabric for a sanitary material by making the superabsorbent fibers non-uniform (Japanese Unexamined Patent Publication No.
207358) and a laminate in which the upper layer and the lower layer are composed of water-absorbing resins having different particle sizes (Japanese Utility Model Application Laid-Open No. 6-589).
No. 52) has been proposed. Certainly, although the blood absorption characteristics are slightly improved by adopting these configurations,
It was still insufficient for practical use.

[0004] To solve this problem, International Publication No. 96
In Japanese Patent No. 28515, a new parameter of blood area ratio to sheep blood is introduced, a blood absorbing resin composition having a high blood area ratio exhibits excellent blood absorption properties, and the surface of the water absorbing resin is highly crosslinked. It discloses that a blood-absorbing resin composition having a high blood area ratio can be obtained.

[0005]

Problems to be Solved by the Invention International Publication No. 96-285
According to the technology disclosed in Japanese Patent Publication No. 15-175, although the blood absorption characteristics are considerably improved, when the liquid-absorbing agent absorbs blood twice or more little by little, the total amount of blood that can be absorbed is obtained. It has been found that there is a problem that the amount is reduced as compared with the case of absorbing at a stretch. That is,
Once the liquid-absorbing agent has absorbed the blood and turned into a gel (blood gel), the amount that could originally be absorbed can no longer be absorbed. For example, even if a liquid absorbing agent can absorb 10 g of blood if it absorbs blood at a stretch,
After the blood gel has been absorbed for a while after absorbing g of blood, it becomes impossible to absorb another 7 g of blood. Therefore, even if the liquid absorbing agent has a large amount of absorbed blood, if the blood gel absorbability is poor, the characteristic of having a large amount of absorbed blood cannot be fully utilized, resulting in poor practicality.

Accordingly, an object of the present invention is to provide a liquid absorbing agent, an absorbent article, and a method for producing the same, which are excellent in blood absorption and blood gel absorption.

[0007]

In order to solve the above problems, the present invention has the following arrangement. (1) A liquid absorbing agent having a blood gel absorption of 3 g / g or more. (2) A liquid-absorbing agent containing a water-absorbing resin having a blood suction amount of 5 g / g or more and 20 to 900% by weight of water with respect to the water-absorbing resin. (3) A method of producing a liquid-absorbing agent from a water-absorbing resin having a blood suction amount of 5 g / g or more and 20 to 900% by weight of water based on the water-absorbing resin. (4) The water content is less than 15% by weight and the blood suction amount is 5 g.
/ G or more of water-absorbent resin and water content of 15% by weight
A method for producing a liquid absorbing agent as described above. (5) An absorbent article having a basis weight of 20 to 10000 g / m ² containing a water-absorbing resin having a blood suction amount of 5 g / g or more and water of 20 to 900% by weight based on the water-absorbing resin. (6) The liquid absorbing agent according to (1) or (2),
Absorbent article used at 00 g / m ² . (7) A water-absorbent resin having a blood suction amount of 5 g / g or more and water having a basis weight of 20 to 900% by weight based on the water-absorbent resin.
Method of making an absorbent article ~10000g / m ^2. (8) The water content is less than 15% by weight and the blood suction amount is 5 g
/ G or more of water-absorbent resin and water content of 15% by weight
A method for producing an absorbent article having a basis weight of 20 to 10000 g / m ² as described above.

When the liquid to be absorbed is artificial urine, there is almost no difference in the amount of liquid absorbed between the case where the liquid is absorbed twice or more and the case where the liquid is absorbed at one time. Is considered to be a problem specific to blood and the like. The present inventors consider that blood is more likely to cause gel blocking than artificial urine.The biggest difference between artificial urine and blood is that blood is a solid component in addition to liquid components such as blood cells. Was considered to be the cause, and it was presumed that blood cells and the like were responsible for inhibiting blood gel absorbability. Further examination, since the inside of the blood cells is water, when the blood is absorbed by the water-absorbent resin, the water in the blood cells is also absorbed by the water-absorbent resin, the surface membrane of the blood cells adhered to the surface of the water-absorbent resin It was thought that the water-absorbent resin gelled in this state, and that the contact between the water-absorbent resin and the new liquid (blood) was hindered by the blood cell surface film. Then, as a means for preventing the surface film of blood cells from adhering to the water-absorbing resin, the present inventors have conceived of absorbing a specific amount of water into the water-absorbing resin, and have arrived at the present invention. The mechanism of action is unclear, but the water-absorbent resin absorbs water, causing the entire water-absorbent resin to gel slightly and almost uniformly, so that blood is unevenly absorbed by only a portion of the water-absorbent resin. Possible reasons are that the problem (become a mamako) is less likely to occur, and that the blood is diluted with water, so that problems unique to blood are less likely to occur.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The liquid absorbing agent of the present invention will be described. The liquid absorbing agent of the present invention is characterized by having a blood gel absorption of 3 g / g or more. The blood gel absorption amount is defined in Examples described later, and is used to quantify the blood absorption amount in a state in which the liquid absorbing agent has absorbed the blood to form a gel. When the blood gel absorption amount is 3 g / g or more, the amount of blood that can be absorbed in total becomes sufficiently large even when the liquid absorbing agent absorbs the blood twice or more little by little. The blood gel absorption is preferably at least 4 g / g, more preferably at least 4.5 g / g.

Examples of the liquid absorbing agent having a high blood gel absorption include those containing a water-absorbing resin having a blood suction amount of 5 g / g or more and water in an amount of 20 to 900% by weight based on the water-absorbing resin. . The blood suction volume is defined in Examples described later, and is used to determine the force of the water-absorbing resin to draw blood. The blood suction amount is preferably 5 g / g or more, more preferably 10 g / g or more. As the sample resin for measuring the blood suction amount, a water-absorbent resin obtained by polymerizing a hydrogel polymer and subjecting it to surface cross-linking treatment as necessary, or including a water-absorbent resin and water It is also possible to use a water-absorbent resin (water content of less than 15% by weight) obtained by drying the water of the liquid absorbing agent.

In the present specification, unless otherwise specified, the term "water-absorbent resin" means not only a water-absorbent resin containing no water but also a substantially dry state containing water in a range of less than 15% by weight. Of water-absorbent resin. The water-absorbing agent is used for a water-absorbing resin having a blood suction amount of 5 g / g or more.
By containing 0 to 900% by weight of water, the blood gel absorption can be improved without lowering the blood absorption. If the amount of water is less than 20% by weight, no improvement in blood gel absorption is observed. On the other hand, if the amount of water is 900
If the content exceeds% by weight, the relative amount of the water-absorbing resin decreases, so that the amount of absorbed blood decreases. In addition, the degree of improvement in blood gel absorption, which should be the effect of water for the same reason, also decreases. In addition, if the water-absorbing resin contained in the liquid-absorbing agent has a blood suction amount of less than 5 g / g, no improvement in the blood gel absorption amount is observed even when the water-absorbing resin contains 20 to 900% by weight of water. The blood suction amount of the water absorbent resin is preferably 10 g / g or more, and more preferably 12 g / g or more. The amount of water is preferably 50 to 400% by weight, more preferably 100 to 2% by weight.
00% by weight.

The amount of blood absorbed here is defined in the examples described later, and is used to determine the amount of the liquid absorbing agent that absorbs blood. In the aforementioned blood suction volume,
While the water-absorbing resin represents the amount of blood itself to be sucked, the amount of blood absorbed does not include those that can be once sucked but cannot be retained in the liquid absorbing agent. Therefore, it can be said that the amount of absorbed blood is a more important factor than the amount of sucked blood from the practicality of the sanitary material.

The above-mentioned liquid-absorbing agent having a high blood gel absorption amount is produced from a water-absorbing resin having a blood suction amount of 5 g / g or more and water in an amount of 20 to 900% by weight based on the water-absorbing resin. It is convenient to post-add water to the water-absorbent resin. From the viewpoint of the water content, the water content of the water-absorbent resin is usually less than 15% by weight. Therefore, water is added to the water-absorbent resin having a water content of less than 15% by weight and a blood suction amount of 5 g / g or more. Thus, the water content may be 15% by weight or more.
Here, the water content refers to the ratio of the weight of water to the total weight of the water absorbent resin and water.

The water-absorbing resin used in the present invention is not particularly limited as long as it absorbs water and causes volume expansion, but is generally obtained by polymerizing a water-soluble unsaturated monomer. Examples of these water-soluble unsaturated monomers include (meth) acrylic acid, (maleic anhydride),
Fumaric acid, crotonic acid, itaconic acid, 2- (meth) acryloylethanesulfonic acid, 2- (meth) acryloylpropanesulfonic acid, 2- (meth) acrylamide-2
Anionic monomers such as methylpropanesulfonic acid, vinylsulfonic acid and styrenesulfonic acid and salts thereof; (meth) acrylamide, N-substituted (meth) acrylamide, 2-hydroxyethyl (meth) acrylate, 2-
Nonionic hydrophilic group-containing monomers such as hydroxypropyl (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, and polyethylene glycol (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylamino Specific examples thereof include amino group-containing unsaturated monomers such as propyl (meth) acrylate and N, N-dimethylaminopropyl (meth) acrylamide, and quaternized products thereof. In addition, in an amount that does not extremely impair the hydrophilicity of the obtained polymer, for example, acrylates such as methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, vinyl acetate, and propionic acid A hydrophobic monomer such as vinyl may be used. One or more of these can be selected and used as the monomer component. However, considering the water absorption properties of the finally obtained water absorbing material, (meth) acrylic acid (salt),
2- (meth) acryloylethanesulfonic acid (salt), 2
Selected from the group consisting of-(meth) acrylamide-2-methylpropanesulfonic acid (salt), (meth) acrylamide, methoxypolyethylene glycol (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate or a quaternized product thereof. Preferably, one or more of these are included, and more preferably those containing (meth) acrylic acid (salt) as an essential component. In this case, (meth) acrylic acid 3
Most preferably, 0 to 90 mol% is neutralized with a basic substance. The water absorption capacity as a water-absorbing resin is 20 to 60 g as a value according to a tea bag method in physiological saline.
/ G. The proportion of the uncrosslinked component, the so-called water-soluble component, is preferably 20% by weight or less, more preferably 10% by weight or less, and the smaller the ratio, the better.

The water-absorbing resin may be a self-crosslinking type obtained without using a cross-linking agent, or a cross-linking agent having a polymerizable unsaturated group and / or a reactive functional group may be used. It may be obtained by using various characteristics in a range that reaches a desired standard. In this case, examples of the internal crosslinking agent used for crosslinking inside the water absorbent resin include, for example, N, N′-
Methylenebis (meth) acrylamide, (poly) ethylene glycol (meth) acrylate, glycerin tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, triallylamine, triallyl cyanurate, triallyl isocyanurate, glycidyl (meth) acrylate , (Poly) ethylene glycol, diethylene glycol, (poly) glycerin, propylene glycol, diethanolamine, trimethylolpropane, pentaerythritol, (poly) ethylene glycol diglycidyl ether, (poly) glycerol (poly) glycidyl ether, epichlorohydrin,
Specific examples thereof include ethylenediamine, polyethyleneimine, (poly) aluminum chloride, aluminum sulfate, calcium chloride, and magnesium sulfate. Among these, one or two or more can be used in consideration of reactivity.

The average particle size of the water-absorbent resin is not particularly limited, but is preferably in the range of 10 to 400 μm.
m is particularly preferred. By crosslinking the vicinity of the surface of the water-absorbent resin, it is possible to increase the blood suction amount and the blood absorption amount of the water-absorbent resin. As the surface cross-linking agent, those having two or more functional groups capable of reacting with the functional groups on the surface of the water-absorbent resin, those having high safety when used in absorbent articles such as sanitary napkins are preferable, for example, Ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, trimethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, pinacol, hydrobenzoin, benzpinacol, cyclopentane-1,
2-diol, cyclohexane-1,4-diol, pentaerythritol, glycerin, diglycerin, polyglycerin, diethanolamine, triethanolamine, polyoxypropylene, oxyethylene-oxypropylene block polymer, sorbit, sorbitan,
Polyhydric alcohols such as sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, trimethylolpropane, pentaerythritol, polyvinyl alcohol, glucose, mannitol, mannitol, sucrose, glucose; ethylene carbonate, propylene carbonate, 4,5-dimethyl -1,3-dioxolan-2-one, 4,4-dimethyl-1,3-dioxolan-2-one, 4-ethyl-1,3-dioxolan-2-one,
-Hydroxymethyl-1,3-dioxolan-2-one, 1,3-dioxan-2-one, 4-methyl-1,
3-dioxan-2-one, 4,6-dimethyl-1,3
Alkylene carbonates such as -dioxan-2-one;
Polyvalent amines such as ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine and polyethyleneimine;
Polyvalent isocyanates such as 2,4-tolylene diisocyanate and hexamethylene diisocyanate; polyvalent oxazolines such as 1,2-ethylenebisoxazoline; 2,2-
Bishydroxymethylbutanol-tris [3- (1-
Aziridyl) propionate], 1,6-hexamethylenediethyleneurea, diphenylmethane-bis-4,
And polyvalent aziridine such as 4'-N, N'-diethyleneurea. One or more of these can be used as the surface crosslinking agent. Among them, polyhydric alcohols and alkylene carbonates are preferable from the viewpoints of blood suction amount and blood absorption amount of the obtained water-absorbent resin, ethylene glycol, diethylene glycol,
Triethylene glycol, polyethylene glycol, propylene glycol, glycerin, diglycerin, polyglycerin, ethylene carbonate, propylene carbonate are preferred, and glycerin is most preferred.

The amount of the surface crosslinking agent to be used is not particularly limited, but is preferably in the range of 0.5 to 10 parts by weight, more preferably 2 to 5 parts by weight, per 100 parts by weight of the water-absorbent resin. If the amount used is less than 0.5 part by weight, the amount of blood absorption and blood absorption of the liquid absorbing agent obtained even if heated for a long time is unlikely to increase. On the other hand, if the amount used exceeds 10 parts by weight, it is difficult to obtain an effect corresponding to an increase in the amount used, and further unreacted substances remain, which not only causes various troubles but also is uneconomical. is there.

In order to subject the water-absorbent resin to the surface cross-linking treatment, usually, the water-absorbent resin and the surface cross-linking agent are uniformly mixed, and the granulated product is heated. To make the mixing of the water-absorbing resin and the surface crosslinking agent uniform, 0 to 50 parts by weight of water and 0 to 60 parts by weight of the hydrophilic organic solvent may be used with respect to 100 parts by weight of the water-absorbing resin. As the hydrophilic organic solvent, lower alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol and t-butanol,
Ethers such as acetone, methyl ethyl ketone, methyl isobutyl ketone, ethers such as dioxane, tetrahydrofuran and diethyl ether, N, N
Amides such as -dimethylformamide and N, N-diethylformamide and sulfoxides such as dimethylsulfoxide.

The mixing method is not particularly limited, and an ordinary mixer can be used. The granulation method is not particularly limited, but extrusion granulation is preferred. When a polyhydric alcohol or an alkylene carbonate is used as the surface cross-linking agent, the heat treatment is preferably performed under the conditions of the temperature of the object to be heated and the heat treatment time represented by the following formula (1).

Log (t) ≧ 15.7 × 10 ³ (1 / T) −24.4 (1) (where, t is a heat treatment time (second), and T is an absolute temperature of an object to be heated ( If the heat treatment is performed under conditions that do not satisfy the expression (1), the blood suction amount and the blood absorption amount will be inferior. Further, it is preferable to carry out the reaction under the condition represented by the following formula (2).

15.7 × 10 ³ (1 / T) −23 ≧ log (t) ≧ 15.7 × 10 ³ (1 / T) −24.4 (2) (where t is the heat treatment time ( Second) and T is the absolute temperature (K) of the object to be heated.) If the heat treatment is performed under conditions not satisfying the expression (2), it is difficult to obtain an effect equivalent to spending a long time. It is uneconomical.

When the surface cross-linking agent is a polyhydric alcohol or an alkylene carbonate, the temperature of the object to be heated and the heat treatment time are from 18 to 70 hours at 170 ° C. to 5 to 18 minutes at 250 ° C. Or less, preferably at 180 ° C for 8 hours or more and 30 hours or less to 210 ° C for 1 hour.
The time is more preferably from 3 hours to 3 hours. If the temperature of the object to be heated is lower than 170 ° C., it takes a very long time to obtain a high blood suction amount and a high blood absorption amount, which is not economical. On the other hand, if the temperature of the object to be heated exceeds 250 ° C., there is a risk of causing thermal degradation depending on the type of the water-absorbing resin used.

The heating method of the present invention is not particularly limited, and may be a conventional dryer or heating furnace, for example, a channel-type stirring dryer, a rotary dryer, a fluidized-bed dryer, a flash dryer, an infrared dryer, Dielectric heating or the like can be used. It is preferable that the shearing force and the crushing force at the time of this heat treatment be as small as possible in order to obtain an excellent blood suction amount and blood absorption amount,
Among the above, a fluidized bed dryer and a flash dryer are preferred.

The absorbent article of the present invention will be described. The absorbent article is formed by combining a water-absorbing resin with necessary members such as hydrophilic fibers. The absorbent article of the present invention contains a water-absorbing resin having a blood suction amount of 5 g / g or more, and 20 to 900% by weight of water based on the water-absorbing resin. In order to manufacture such an absorbent article, it may be manufactured from a water-absorbent resin and water satisfying the above conditions, and the order of combination and the like are not particularly limited, but examples include the following method. Can be

The above-mentioned liquid absorbing agent is combined with a hydrophilic fiber or the like. Water is added after the water-absorbing resin is combined with the hydrophilic fiber or the like. After water is added to the hydrophilic fiber or the like, it is combined with a water-absorbing resin. Further, from the viewpoint of the water content, as described in the description of the liquid absorbing agent, water is added to a water-absorbing resin having a water content of less than 15% by weight and a blood suction amount of 5 g / g or more. The water content may be 15% by weight or more. Basis weight 20 to 10000
g / m < ² > is common, and 100-1000 g / m <2>.
The range of m ² is preferable, and the range of 200 to 600 g / m ² is more preferable.

As the hydrophilic fiber used for the absorbent article of the present invention, any known fibers can be used. For example, pulverized wood pulp, cotton linter, crosslinked cellulose fiber, rayon, cotton, wool, acetate, vinylon, and the like can be used. Among them, those in the form of air-laid pads of ground wood pulp are preferred. The absorbent article of the present invention may include a number of known members such as a diffusion layer, a leg elastic member, a waist elastic member, and a tape.

The absorbent article of the present invention exhibits excellent absorption characteristics for blood as described above, but also contains water containing protein components like blood, for example, milk, breast milk, and vaginal discharge. It also shows excellent absorption characteristics for the same. In addition, it exhibits excellent absorption characteristics to urine, seawater, cement water, soil water, fertilizer-containing water, rainwater, drainage, and the like, similar to conventional water-absorbent resins. Specific applications include sanitary napkins, tampons, medical blood-absorbing articles, wound protectors,
In addition to applications requiring blood absorption properties, such as wound healing materials and treatment liquid for surgical use, it is also suitably used in various industrial fields such as sanitary materials such as disposable diapers and incontinence pads, civil engineering, and agricultural and horticultural arts. Furthermore, it can be obtained by interposing a deodorant, a fragrance, a drug, a plant growth aid, a bactericide, a foaming agent, a pigment, a dye, a hydrophilic short fiber, a fertilizer, etc. in the liquid absorbing agent or the absorbent article of the present invention. A new function can be given to the liquid absorbing agent.

[0028]

The present invention will be described in more detail with reference to the following Examples and Comparative Examples, but the present invention is not limited thereto. In the examples, “parts” means “parts by weight” unless otherwise specified.

Various properties of the liquid absorbing agent were measured by the following methods. (A) Blood Suction Volume 16 sheets of toilet paper (55 mm × 75 m) immersed in 20 ml of sheep blood (sheep defibrillated blood; manufactured by Japan Biotest Laboratory, the same applies hereinafter) in a petri dish having an inner diameter of 95 mm
m) Approximately 1 g of the sample resin is added on the top, and after absorbing for 5 minutes,
The swollen gel was collected and its weight was measured. The weight of the swollen gel after absorption was divided by the weight of the original sample resin to calculate the blood suction amount (g / g) of the sample resin. (B) Amount of absorbed blood 1 g of the sample resin is spread as uniformly as possible in a Petri dish having an inner diameter of 60 mm, and 5 g of sheep blood is dropped thereon to obtain a gel that has absorbed blood. Most water absorbent resins do not form a uniform gel in this state.

Then, after leaving for 5 minutes, a kitchen towel (10
Place the gel on the gel and put a weight on it (load 0.
7 psi = 49 g / cm ² ), and the weight of the kitchen towel one minute later was measured, and the change in the weight was subtracted from the dropped sheep blood to determine the blood absorption. (C) Absorption of blood gel 1 g of the sample resin is spread as uniformly as possible in a petri dish having an inner diameter of 60 mm, and 5 g of sheep blood is dropped thereon to obtain a blood-sucking gel.

After standing for 60 minutes, 5 g of sheep blood was dropped on the gel that absorbed the blood, and after standing for 5 minutes, a kitchen towel (10 sheets) was placed on the gel, and a weight (0.7 p.
si = 49 g / cm ² ), the weight of the kitchen towel one minute later was measured, and the change in the weight was subtracted from the dropped sheep blood to obtain the blood gel absorption amount. (D) Blood return amount About 15 g of sheep blood is dropped on the central part of the absorbent article with a syringe,
After a lapse of about 5 minutes, the amount of return was evaluated by touching the surface of the absorbent article with the hand, and this was defined as the amount of blood returned. Further, after 1 hour, 15 g of sheep blood is dropped with a syringe, and after about 5 minutes,
The amount of return was evaluated by touching the surface of the absorbent article with the hand, and this was defined as the amount of blood returned. [Example 1] In the production of a water-absorbent resin having a carboxyl group, trimethylolpropane as an internal crosslinking agent was added to 4400 parts of a 37% by weight aqueous solution of sodium acrylate (75 mol% neutralization ratio) as a monomer component. 2.72 parts of triacrylate was dissolved to obtain a reaction solution. Next, the reaction solution was degassed for 30 minutes under a nitrogen gas atmosphere.

Next, the reaction solution was supplied to a reactor equipped with a jacketed stainless steel double-armed kneader having two sigma-type blades, and the reaction solution was maintained at 30 ° C. and the inside of the reactor was filled with nitrogen gas. Replaced. Subsequently, while stirring the reaction solution, sodium persulfate as a polymerization initiator was added.
When 1 part and 1.1 parts of sodium sulfite as a reducing agent for accelerating the decomposition of the polymerization initiator were added, polymerization started about 1 minute later. Then, polymerization was carried out at 30 ° C. to 80 ° C., and the hydrogel polymer was taken out 40 minutes after the initiation of the polymerization.

The obtained hydrogel polymer was spread on a wire mesh and dried with hot air at 150 ° C. for 2 hours. Next, the dried product was pulverized using a hammer mill, and further classified with a 30-mesh wire mesh (mesh size: 600 μm) to obtain an irregularly crushed water-absorbent resin (1) having an average particle size of 220 μm. Next, with respect to 100 parts of the water absorbent resin (1),
An aqueous liquid containing 0.5 part of glycerin, 2 parts of water and 0.5 part of isopropyl alcohol was mixed with a Loedige mixer (M
5R, manufactured by Redige Co., Ltd.) for about 30 minutes, put the resulting water-absorbent resin mixture (1) in a dryer at 220 ° C. for 2 minutes.
Heat treatment was performed for a time to obtain a reference water-absorbent resin (1).
The blood suction amount of the reference water absorbent resin (1) is 12.4 g /
g, water content was 0.5% by weight. 20 parts of water was dropped and mixed with 100 parts of the obtained water-absorbing resin for reference (1) to obtain a liquid absorbing agent (1) of the present invention. Example 2 Reference water-absorbent resin (1) 1 obtained in Example 1
To 50 parts of water, 50 parts of water was dropped and mixed, and the liquid absorbing agent of the present invention (2)
I got [Example 3] Reference water-absorbent resin (1) 1 obtained in Example 1
100 parts of water and 100 parts of water were dropped and mixed to obtain a liquid absorbing agent (3) of the present invention. [Example 4] Reference water-absorbent resin (1) 1 obtained in Example 1
200 parts of water was dripped and mixed with 00 parts to obtain a liquid absorbing agent (4) of the present invention. [Example 5] The reference water-absorbent resin (1) 1 obtained in Example 1
400 parts of water was dropped and mixed with 00 parts to obtain a liquid absorbing agent (5) of the present invention. [Example 6] The reference water-absorbent resin (1) 1 obtained in Example 1
To 900 parts of water was added 900 parts of water dropwise to obtain a liquid absorbing agent (6) of the present invention. Comparative Example 1 An aqueous liquid containing 0.5 part of glycerin, 2 parts of water and 0.5 part of isopropyl alcohol was mixed with 100 parts of the water-absorbent resin (1) obtained in Example 1 using a Loedige mixer (M5R, And the resulting water-absorbent resin mixture (1) was placed in a dryer for 18 minutes.
Heat-treated at 0 ° C for 1 hour, and water-absorbent resin for reference (2)
I got The blood suction volume of the reference water absorbent resin (2) is 2.6.
g / g, and the water content was 1.3% by weight. 20 parts of water was dropped and mixed with 100 parts of the obtained reference water-absorbent resin (2),
A comparative liquid absorbing agent (1) was obtained. Comparative Example 2 Reference water-absorbent resin (2) 1 obtained in Comparative Example 1
To 50 parts of water, 50 parts of water were dropped and mixed to obtain a comparative liquid absorbing agent (2). Comparative Example 3 Reference water-absorbent resin (2) 1 obtained in Comparative Example 1
To 100 parts of water, 100 parts of water was dropped and mixed, and a comparative liquid absorbing agent (3)
I got [Comparative Example 4] Reference water-absorbent resin (2) 1 obtained in Comparative Example 1
200 parts of water were dropped and mixed with 00 parts, and a comparative liquid absorbing agent (4)
I got [Comparative Example 5] The reference water-absorbent resin (2) 1 obtained in Comparative Example 1
To 400 parts of water, 400 parts of water were dropped and mixed, and a comparative liquid absorbing agent (5)
I got Comparative Example 6 The reference water-absorbent resin (2) 1 obtained in Comparative Example 1
To 900 parts of water, 900 parts of water were dropped and mixed, and a comparative liquid absorbing agent (6)
I got [Comparative Example 7] Reference water-absorbent resin (1) 1 obtained in Example 1
To 10 parts of water, 10 parts of water was dropped and mixed to obtain a comparative liquid absorbing agent (7). [Comparative Example 8] Reference water-absorbent resin (1) 1 obtained in Example 1
1900 parts of water was dropped and mixed with 00 parts to obtain a comparative liquid absorbing agent (8).

The reference water-absorbent resin (1) obtained above,
With respect to the liquid absorbing agents (1) to (6), the reference water absorbing resin (2), and the comparative liquid absorbing agents (1) to (8), the blood absorption amount and the blood gel absorption amount were measured. Table 1 shows the results.

[0035]

[Table 1]

Each of the liquid absorbing agents (1) to (6) has a large amount of blood absorption and blood gel absorption and is excellent in practicality. On the other hand, as shown in the reference water-absorbing resins (1) and (2), those to which no water is added have a large blood absorption but a small blood gel absorption. In Comparative Liquid Absorbents (1) to (6), blood gel absorbability was not improved when water was added because the blood suction amount of Reference Water Absorbent Resin (2) was small. In Comparative Liquid Absorbent (7), the effect was not seen because the amount of water added was small, and the blood gel absorption was not sufficiently improved. In the comparative liquid absorbing agent (8),
Since the amount of water added is large and the relative water-absorbing resin amount is insufficient, a decrease in blood absorption is seen, and for the same reason, an increase in blood gel absorption, which should have been the effect of the addition of water. The degree also decreases as compared with the liquid absorbing agents (1) to (6). Example 7 100 parts of the liquid absorbing agent (1) obtained in Example 1 and 100 parts of pulverized pulp were dry-mixed, air-formed and compressed to a density of 0.15 g / cc and a basis weight of 0.05 g / cm. ^Two
Was obtained. Next, the liquid-absorbent structure cut into 6 cm × 20 cm, a liquid-permeable polypropylene topsheet, two tissue papers, a liquid-impermeable polyethylene backsheet including leg gathers and waist gathers, and two tape fasteners The absorbent component (1) consisting of was assembled by hand by fastening individual components with double-sided tape. [Examples 8 to 12 and Comparative Examples 9 to 16] In Example 7, liquid absorbing agents (2) to (6) or comparative liquid absorbing agents (1) to (8) were used instead of liquid absorbing agent (1). Except that the density was 0.14 to 0.17 g / c in the same manner as in Example 7.
c, a liquid-absorbing structure having a basis weight of 0.047 to 0.052 g / cm ² was obtained. Using the obtained liquid absorbing structure,
In the same manner as in Example 7, the absorbent article (2) of the present invention
(6) and comparative absorbent articles (1) to (8) were assembled.

The absorbent articles (1) to (6) obtained above
The blood return amount of each of the comparative absorbent articles (1) to (8) was evaluated. Table 2 shows the results.

[0038]

[Table 2]

[0039]

According to the present invention, it is possible to obtain a liquid absorbing agent and an absorbent article having excellent blood absorbability and blood gel absorbability. Therefore, even when the liquid absorbing agent or the absorbent article divides blood into two or more portions and absorbs it little by little, it is possible to absorb a sufficiently large amount of blood in total.

Claims (8)

[Claims] 1. A liquid absorbing agent having a blood gel absorption of 3 g / g or more. 2. A liquid-absorbing agent containing a water-absorbing resin having a blood suction amount of 5 g / g or more, and 20 to 900% by weight of water based on the water-absorbing resin. 3. A method for producing a liquid absorbing agent from a water-absorbing resin having a blood suction amount of 5 g / g or more and 20 to 900% by weight of water based on the water-absorbing resin. 4. A method for producing a liquid-absorbing agent comprising adding water to a water-absorbent resin having a water content of less than 15% by weight and a blood suction amount of 5 g / g or more to make the water content 15% by weight or more. 5. An absorbent article having a basis weight of 20 to 10,000 g / m ² containing a water-absorbent resin having a blood suction amount of 5 g / g or more and water of 20 to 900% by weight based on the water-absorbent resin. 6. The liquid absorbent according to claim 1 or 2 having a basis weight of 2.
Absorbent article used in 0~10000g / m ^2. 7. An absorbent article having a basis weight of 20 to 10000 g / m ² is produced from a water-absorbing resin having a blood suction amount of 5 g / g or more and 20 to 900% by weight of water based on the water-absorbing resin. Method. 8. A water-absorbing resin having a water content of less than 15% by weight and a blood suction amount of 5 g / g or more is added with water to a water content of 15% by weight or more, and has a basis weight of 20 to 10,000 g / m ^2.
Method for producing an absorbent article.