JPS6321902A - Absorbable article - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an absorbent article using an absorbent body made by disposing a specific water-absorbing polymer on pulverized pulp and/or absorbent paper.

More specifically, the absorbent properties of aqueous liquids, including body fluids such as urine, sweat, and menstrual blood, are remarkable by using a water-absorbing polymer whose liquid absorption, suction, and soluble content are controlled within a certain range. The present invention relates to improved absorbent articles.

(Prior art) Conventionally, as water-absorbing polymers, hydrolysates of starch-acrylonitrile graft polymers, neutralized products of starch-acrylic acid graft polymers, crosslinked carboxymethyl heptylulose, and acrylic ester-vinyl acetate copolymers have been used. Saponified products, partially neutralized polyacrylate crosslinked products, crosslinked polyvinyl alcohol modified products, crosslinked inbutylene-maleic anhydride copolymers, etc. are known.

These water-absorbing polymers are generally composited with cotton, pulp, paper, sponge, foamed resin moldings, etc., and are put into practical use as absorbent articles such as disposable diapers, sanitary napkins, and wall materials to prevent condensation. .

(Problem to be solved by the invention) However, with these conventional absorbent articles using water-absorbing polymers, for example, disposable diapers have a large amount of rebound when pressurized, and clothes and futons get dirty due to side leakage. Industrial absorbent products such as wall materials for preventing condensation have many drawbacks, such as the inability to obtain sufficient moisture absorption, moisture conditioning, and water retention capabilities over the long term.

As described above, an absorbent article that has sufficient absorbent properties and can be used without problems in various fields has not yet appeared.

(Means and effects for solving the problem) In view of this situation, the inventors of the present invention have conducted extensive research, and as a result, the amount of physiological saline absorbed (hereinafter referred to as
Sometimes it is simply the amount of liquid absorbed. ), the amount of artificial urine aspirated (hereinafter sometimes simply referred to as the amount of suction), and the amount of soluble content of the water-absorbing polymer when saturated and swollen with ion-exchanged water (hereinafter, when applied to absorbents, We have found a way to solve the above problems and have arrived at the present invention.

That is, in the present invention, the absorption amount of physiological saline is 30 to 8011
/l polymer range, the amount of artificial urine aspirated is 141711 polymer 1 or more, and the soluble content of the polymer when saturated and swollen with 1-ON exchange water is 30% by weight or less, and the water-absorbing polymer is ground pulp and/or The present invention relates to an absorbent article characterized by using an absorbent body arranged on absorbent paper.

An important point in the present invention is that the liquid absorption amount, suction amount, and soluble content of the water-absorbing polymer used in the absorbent body are within a certain range.

When the absorbent article is a sanitary material such as a disposable diaper or sanitary napkin, the suction amount of the water-absorbing polymer is determined by quickly absorbing urine or menstrual blood diffused into the pulp or paper, and reducing the dispersibility of the pulp or paper over time. This is an essential factor in obtaining an absorbent article that can be stably retained, does not cause discomfort to the skin, and has a small amount of urine and menstrual blood retentivity. Furthermore, in the case of industrial absorbent articles such as wall materials for preventing condensation, the amount of suction of the water-absorbing polymer is an important factor in eliminating the wet feeling on the surface of the absorbent article.

For example, when the absorbent article is a sanitary material such as a disposable diaper, the soluble content is determined to prevent the so-called gel blocking phenomenon in which the water-absorbing polymer deteriorates during use and prevents the diffusion of body fluids such as urine. This is an essential factor in obtaining an absorbent article that does not lose its initial absorbent properties and does not cause leakage of body fluids even when using

Also, in the case of industrial absorbent articles, the amount of soluble content is an essential factor in order to obtain long-term stable moisture absorbing power, moisture control power, and water retention power.

Furthermore, the amount of liquid absorbed by a water-absorbing polymer is an important factor in that it affects the absorption capacity of an absorbent article, but if you try to increase the amount of liquid absorbed by a water-absorbing polymer, the amount of absorption may decrease or There is a trade-off between the amount of suction and the amount of soluble content, which may increase the amount and adversely affect the performance of the absorbent article.

Therefore, it is possible to obtain the absorbent article of the present invention having unprecedented excellent absorption properties only by using a water-absorbing polymer whose liquid absorption amount, suction amount, and soluble content are controlled within specific ranges. It becomes possible.

The water-absorbing polymer used in the present invention is not particularly limited as long as the amount of liquid absorbed, the amount of suction, and the amount of soluble content are within the above-mentioned specific ranges, and it swells in water to form a hydrogel.
For example, hydrolysates of starch-7 acrylonitrile graft polymers, neutralized starch-acrylic acid graft polymers, saponified products of acrylic ester-vinyl acetate copolymers, cross-linked polyvinyl alcohol modified products, partially neutralized polyacrylics. It can be selected from among acid crosslinked products, crosslinked isobutylene-maleic anhydride copolymers, and the like. Among these, partially neutralized polyacrylate crosslinked products are preferred. Also,
These water-absorbing polymers may be treated with granulation or post-crosslinking, but those that are post-crosslinked to increase the crosslinking density near the surface of the polymer particles are particularly preferred.

If the amount of physiological saline absorbed by the water-absorbing polymer used in the present invention is larger than that of the 8,097 g polymer, the amount of absorption and the amount of soluble matter cannot be controlled within a preferable range due to the above-mentioned trade-off. , 309/9 polymer, it is not preferable because the absorbent capacity of the absorbent article itself is significantly reduced. Furthermore, if the amount of artificial urine sucked is smaller than that of the 141/I polymer, it is not preferable because a large amount of body fluids will return during use of the resulting absorbent article such as a disposable diaper, and this will cause discomfort to the skin.

Furthermore, if the amount of soluble content, that is, the proportion of the amount of polymer eluted into ion-exchanged water when the water-absorbing polymer is saturated and swollen with ion-exchanged water is more than 30% by weight, water absorption may occur due to the gel blocking phenomenon described above. The absorption capacity of the absorbent polymer is not fully demonstrated, resulting in side leakage in the resulting absorbent articles such as disposable diapers, and industrial absorbent articles such as wall materials for preventing condensation may not have sufficient moisture absorption and humidity control ability over the long term.・Unfavorable because water retention capacity cannot be obtained.

The absorbent article of the present invention uses an absorbent body in which a water-absorbing polymer whose physical properties are controlled to have the above-described specific values is arranged on a crushing valve and/or absorbent paper. In order to obtain such an absorbent body, conventionally known methods employed for processing water-absorbing polymers into absorbent bodies in a convenient shape for constructing absorbent articles, such as sheets or films, can be used. Bye. Therefore, the absorbent body used in the present invention may be, for example, one in which a water-absorbing polymer is placed between absorbent paper or non-woven fabric and held there for a long time, or a sheet is prepared by mixing the pulverizing valve and the water-absorbing polymer in a dry or wet process. It may also be shaped into a shape.

In order to obtain the absorbent article of the present invention using the absorbent body obtained in this manner, the absorbent body can be used alone or in appropriate combination with other components to form the absorbent article, depending on the intended use of the absorbent article. do it. For example, in the case of a sweat-absorbing pad or a wall material for preventing condensation, the obtained absorbent body can be attached to a wall placed on a 7-ton surface to form an absorbent article.

Further, in the case of sanitary materials such as paper diapers and sanitary napkins, the obtained absorbent body can be arranged and combined between a body fluid permeable sheet and a body fluid leakproof sheet to form an absorbent article.

(Effects of the Invention) Since the absorbent article of the present invention uses a water-absorbing polymer whose physical properties are controlled to specific values, it has a large absorption capacity for aqueous substances, and the polymer does not cause gel blocking phenomenon. Therefore, it has an unprecedented feature of being able to stably maintain excellent absorption properties over time.

Therefore, when the absorbent article of the present invention is used as a sanitary material such as a disposable diaper or a sanitary napkin, it has a very small weight when pressurized and does not leak from the sides during use, so it does not cause any discomfort to the skin and can be used for a long time. It can also withstand use. It can also be used as industrial absorbent products such as wall materials to prevent condensation.
You can obtain products that retain excellent moisture absorption, moisture conditioning, and water retention capabilities over a long period of time.

(Examples) Examples will be shown below, but the present invention is not limited to these examples. In the examples shown below, all unindicated limits, parts, and q represent parts by weight and % by weight.

In addition, the amount of liquid absorbed, the amount of suction, and the amount of soluble content of the water-absorbing polymer were measured by the following methods.

1) Absorption amount of physiological saline: Approximately 0.2 y of water-absorbing polymer was uniformly placed in a tea bag-type bag made of non-woven fabric (40 m x 150 n), and immersed in a large excess of physiological saline (0.9 y saline). After the polymer was sufficiently swollen, the tea bag containing the swollen gel was pulled up for 5 seconds and 24 sheets of toilet paper (57yrat x 50m, x 9g/m
f) Drain on top for 10 seconds and measure weight. Using the weight of only the tea bag type bag after liquid absorption as a blank, the amount of liquid absorbed by the water-absorbing polymer was calculated according to the following formula.

2) Amount of artificial urine aspirated: Approximately 1 y of water-absorbing polymer was added onto 16 sheets of toilet paper (55 x 75 mm) soaked in 20 ml of artificial urine with the following composition, and after absorbing the liquid for 10 minutes, the swollen gel was collected. The weight (5) was measured. Based on the weight of the water-absorbing polymer before liquid absorption i (W,), the suction amount of the water-absorbing polymer was calculated according to the following formula.

Artificial urine suction volume C1/l polymer) = W/W0 Composition of artificial urine 3) Soluble content of water-absorbing polymer when saturated and swollen with ion-exchanged water: Passes through a 48-mesh sieve and passes through a 60-mesh sieve A water-absorbing polymer adjusted to a particle size that does not pass through 0.
5g was added to 1000g of ion-exchanged water, stirred at 25°C for 8 hours, and then filtered through filter paper (Toyo Rokei/l62). The amount of carboxylic acid in the obtained filtrate was titrated with a 0.1N aqueous sodium hydroxide solution and then back titrated with 0.1N hydrochloric acid to determine the amount of soluble content using the following formula.

Soluble content (%) = 0. ITa/1000X (7
2Tb+94(Ta-Tb))/Ta X 1000/
MXI 10.5 ) Reference example 1 Sodium acrylate 74.95 molti, acrylic acid 2
40 of an acrylate monomer consisting of 5 molti and 0.05 molti trimethylolpropane triacrylate.
4,000 parts of an aqueous solution of 4,000 parts of ammonium persulfate and 0.1 part of sodium bisulfite were allowed to stand and polymerize at 50 to 80°C in a nitrogen atmosphere to obtain a gel-like hydropolymer. This gel-like water-containing polymer was dried in a hot air dryer at 180°C, crushed in a hammer-type crusher, and sieved through a 20-mesh wire mesh to obtain Reference Example 2. Two parts of glycerin, two parts of water, and two parts of ethyl alcohol were mixed using a paddle mixer, and the resulting mixture was continuously heated using a paddle dryer.

The average residence time in this paddle dryer was 20 minutes, and the material temperature at the outlet was 190°C. In this way, a post-crosslinked water-absorbing polymer (2) was obtained.

Reference Example 3 11,100 parts of the water-absorbing polymer obtained in Reference Example 1 was heat-treated with metal using a paddle dryer in the same manner as in Reference Example 2 to obtain a water-absorbing polymer (3).

Reference example 4 Sodium acrylate 74.97 molti, acrylic acid 2
5 molti and N,N'methylenebisacrylamide 0
．． After drying 4000 parts of a 40% aqueous solution of an acrylate monomer consisting of 0.03 mol. The mixture was pulverized and sieved through a 20-mesh wire mesh, and the material that passed through 20 meshes (hereinafter referred to as water-absorbing polymer (4)) was collected.

Reference Example 5 100 parts of the water-absorbing polymer (4) obtained in Reference Example 4 was mixed with 0.5 part of ethylene glycol diglycidyl ether using a ribbon blender, and the heating medium temperature of the jacket of the ribbon blender was set to 180'C. Then, heat treatment was performed for 30 minutes to obtain a water-absorbing polymer (5).

Reference Example 6 The amount of sodium acrylate in Reference Example 4 was 74.7
Mol%, N, N' amount of methylenebisacrylamide is 0
．． A water-absorbing polymer (6) was obtained in the same manner as in Reference Example 4 except that the amount was changed to 3 mol.

Reference Example 7 Sodium acrylate 74.995 mol Acrylic acid 25
40 of an acrylate monomer consisting of molti and 0.005 molti of trimethylolpropane triacrylate
4000 parts of an aqueous solution was subjected to standing polymerization in a nitrogen atmosphere at 50 to 80°C using 0.6 parts of ammonium persulfate and 0.2 parts of sodium bisulfite to obtain a gel-like hydropolymer. After drying this gel-like water-containing polymer in a hot air dryer at 180° C., a portion of the gel was collected.

Reference Example 8 Water-absorbing polymer obtained in Reference Example 7 (100 parts of strength, 1 part of ethythmium)
After mixing 0.5 i of IJ col cyclocidyl ether with a ribbon blender, the heat medium temperature of the jacket of the ribbon blender was raised to 180°C and heat treatment was performed for 30 minutes to obtain a water-absorbing polymer (8).

Example 1 Pulverized pulp 24! i was divided into approximately half of the upper layer and the lower layer, and between the upper and lower layers, the water-absorbing polymer obtained in Reference Example 1 (1
) was uniformly spread at 1.51, compressed the pulverized pulp, and
With c+ytX27, an absorbent material having a thickness of about 6 mm was obtained. This absorbent material is sandwiched between one sheet of polyethylene film and one sheet of tissue paper to create a disposable diaper-like absorbent article (1).
I got it.

60 g of artificial urine having the above composition was poured into the center of the obtained absorbent article (1) from the tissue paper side to absorb it. After standing for 10 minutes and 60 minutes, cover each absorbent article (1) with 10 paper towels of 23 cIIL x 23 cML, 40. After applying pressure of F/i for 1 minute, the amount of returned artificial urine absorbed by the paper towel was measured. In addition, the diffusivity of the poured artificial urine was visually observed to see the degree of disappearance of the liquid droplets in the artificial urine, and the results were evaluated in three stages from ○ to Δ to ×. The results are shown in Table 1. In addition, the measurement results of the liquid absorption amount, suction amount, and soluble content of the water-absorbing polymer (1) used to obtain the absorbent article (1) are also listed in Table 1.

Examples 2 to 5 and Comparative Examples 1 to 3 Water absorbent polymers (2) to (5) obtained in Reference Examples 2 to 5 and Reference Examples 6 to 8 were used instead of water absorbent polymer (1) in Example 1. Water-absorbing polymers (6) to (8) obtained in
) in the same manner as in Example 1, except for using each of
Absorbent articles (2) to (5) and comparative absorbent articles (1) to
(3) was obtained.

Using each of the obtained absorbent articles (2) to (5) and comparative absorbent articles (1) to (3), the returned amount and diffusivity of artificial urine were evaluated in the same manner as in Example 1. did. The results are shown in Table 1. In addition, the measurement results of the liquid absorption amount, suction amount, and soluble content of the water-absorbing polymers (2) to (8) are also listed in Table 1.

Example 6 The water-absorbing polymer (1) obtained in Reference Example 1 and a pulverized part-shaped absorber were obtained. This absorber is used as it is as an absorbent article (6) for preventing condensation, and the cycle of moisture absorption by blowing steam from a steam generator and drying operation by a dryer is repeated to improve the moisture absorption performance of the surface of the absorbent article. The evaluation was based on the feel of the product.

The evaluation results are shown in Table 2.

Examples 7 to 10 and Comparative Examples 4 to 6 The water absorbing polymer in Example 6 (instead of 11, water absorbing polymers (2) to (5) obtained in Reference Examples 2 to 5 and Reference Examples 6 to 8 were used instead of The obtained water-absorbing polymers (6) to (8)
) in the same manner as in Example 6, except for using each of
Absorbent articles (7) to QO for preventing dew condensation and comparative absorbent articles (4) to (6) were obtained.

Obtained absorbent article (force ~ αI and comparative absorbent article (4
) to (6), the moisture absorption performance was evaluated in the same manner as in Example 6. The results are shown in Table 2.

Table 2 (Note 1) O: Good dry feel.

×: It feels wet and has condensation.

Claims (1)

[Claims] 1. The amount of physiological saline absorbed is in the range of 30 to 80 g/g polymer, the amount of artificial urine aspirated is 14 g/g polymer or more, and the soluble content of the polymer is 30% by weight or less when saturated and swollen with ion-exchanged water. An absorbent article characterized by using an absorbent body formed by disposing a water-absorbing polymer as follows on pulverized pulp and/or absorbent paper.