JPH04119156A - Absorbing material and absorbing article - Google Patents

Abstract

PURPOSE:To obtain an absorbing material useful for sanitary napkin, paper diaper, incontinent pad, mother's milk pad, medical pad, agricultural and horticultural water retaining material, etc., having specific values in density, amount absorbed under pressure and removal ratio of absorbing polymer, consisting mainly of a water absorbing polymer and hydrophilic fibers. CONSTITUTION:The objective absorbing material consisting mainly of a water absorbing polymer [preferably crosslinked polymer of water-soluble ethylenic monomer consisting essentially of acrylic acid (salt)] and hydrophilic fibers (e.g. wood pulp fibers) and having 0.1-0.5g/cm<3> density, 11-25g/g amount absorbed of sodium chloride injection under pressure and <=45% removal ratio of absorbing polymer. The amount of the hydrophilic fibers is preferably 5-500 pts.wt. based on 100 pts.wt. water absorbing polymer.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a novel thin absorbent body mainly composed of a water-absorbing polymer and hydrophilic fibers, and an absorbent article using the same.

(Prior art) Most of the absorbent materials used in absorbent articles such as disposable disposable diapers and sanitary napkins currently on the market have changed to composites of hydrophilic fibers such as cotton pulp and paper and water-absorbing polymers. There is. Functions required of these absorbents using a relatively large amount of water-absorbing polymer include absorption capacity, thinness and lightness, and shape retention, and all of these must be satisfied.

However, although the absorbent materials currently in use are almost satisfactory in terms of absorption capacity, they are not satisfactory in terms of thinness, lightness, and shape retention. It has not been possible to create absorbent articles without major leaks.

(Problems to be Solved by the Invention) Therefore, an object of the present invention is to provide a novel absorbent body and an absorbent article. Another object of the present invention is to provide an absorbent body and an absorbent article that are thin and lightweight, have a large absorption capacity, and have little leakage.

The inventors of the present invention have carefully studied the absorbent material in order to create an absorbent article that is thin and lightweight, has a large absorption capacity, and has little leakage. The present invention was completed by using an absorber that was controlled within a certain range.

(Means for Solving the Problems) These objects are to provide an absorbent body mainly composed of a water-absorbing polymer and a hydrophilic fiber, the absorbent body having a density of 0.1 to 0.
．． 5g/cm3, absorption amount under pressure for physiological saline is 1
This is achieved by using an absorbent body characterized in that the shedding rate of the water-absorbing polymer is in the range of 1 to 25 g/g and the shedding rate of the water-absorbing polymer is 45% or less.

These objects are absorbent articles consisting of a liquid-permeable surface material, a liquid-impermeable backing material, and an absorbent layer sandwiched between them, in which part or all of the absorbent layer conforms to Category 1 above. This is also achieved by an absorbent article (second invention) characterized by being an absorbent body.

(Function) The important point of the present invention is that since the absorber is mainly made of a water-absorbing polymer, it is a thin absorber with excellent absorption capacity, and the water-absorbing polymer does not fall off even after absorbing liquid. That is the point.

In other words, due to the low shedding rate of the water-absorbing polymer,
The absorbent body is not destroyed even after absorbing liquid, so even when liquid is absorbed again in the second or third stage, the absorbent body quickly absorbs urine and menstrual blood without reducing the wicking speed of the absorbent body. be able to. Therefore, there is less leakage.
An absorbent article with a dry feel can be obtained. Also,
The absorption capacity under pressure of the absorber is an important factor in making absorbent articles because if it is too small or too large, it may not be possible to reduce the weight of the absorber, or the absorber may break and leak. be. If the density is too low, liquid absorption and diffusion will be slow and leakage will occur, making it impossible to substantially reduce the thickness and making it impractical. Therefore, only by using an absorbent body with a well-balanced density, absorption capacity under pressure, and shedding rate can it be possible to produce a thin and lightweight absorbent article that does not cause discomfort.

Therefore, a further important point of the present invention is that the absorbent body is a mixture of a water-absorbing polymer and a synthetic pulp (weight ratio 100:1 to 30) in the presence of water, and a hydrophilic fiber that has a weight relative to the water-absorbing polymer. Ratio 100:5-500, preferably 100:10-2
00, and the mixture has a density of 0.00. 1~0.
5g/cm3, preferably 0.15-0.4g/cm
3. It is heat-compressed.

In order to reduce the shedding rate of water-absorbing polymers, methods have been proposed, such as using various binders to fix the water-absorbing polymer or encapsulating the water-absorbing polymer in a fiber matrix. The resulting absorbent usually contains
There is a contradictory relationship between the shedding rate of a water-absorbing polymer and the amount of absorption under pressure.

Therefore, currently commercially available absorbents have the above-mentioned physical properties; a density of 0.1 to 0.5 g/cm3, an absorption amount under pressure of physiological saline in the range of 11 to 25 g/g, and a water-absorbing polymer. There is no one that satisfies all dropout rates of 45% or less.

An absorbent material that satisfies all of these physical properties is a mixture of a water-absorbing polymer and synthetic pulp (polymerization ratio of 100:1 to 30) in the presence of water, and a mixture of hydrophilic fibers and the water-absorbing polymer at a weight ratio of 100:1. 5 to 500, and the mixture has a density of 0.
．． It is heat-compressed to 1 to 0.5 g/cm3.

The water-absorbing polymer in the present invention may be any polymer that generally has water-absorbing properties, such as water-soluble ethylene containing (meth)acrylic acid or its salt as a main component and optionally adding a crosslinking agent. In addition to (crosslinked) polymers of sexually unsaturated monomers, crosslinked products of polyethylene oxide, polyvinylpyrrolidone, sulfonated polystyrene, and polyvinylpyridine, saponified products of starch-poly(meth)acrylonitrile graft polymers, starch-poly(meth)acrylonitrile graft polymers, etc. ) Acrylic acid (and salts thereof) graft copolymers (and crosslinked products thereof), starch-poly(meth)acrylic ester graft copolymers (and crosslinked products thereof), starch-poly(meth)acrylic ester graft copolymers Examples include hydrolyzates of. Preferably, it is a (crosslinked) polymer of a water-soluble ethylenically unsaturated monomer containing acrylic acid or an acrylate as a main component, and more preferably an acrylic acid (salt) crosslinked polymer. Either one is fine. Moreover, two or more kinds of these water-absorbing polymers may be used. The water-absorbing polymer used is 5 g
/g, preferably 20-80 g/g, most preferably 35-60 g/g, and are substantially dry particles. Water-absorbing polymers usually contain a certain amount of water due to their characteristics, but the term "substantially dry" as used herein refers to a state in which the individual particles cannot stick to each other under a normal atmosphere.

The shape of the particles may be spherical, granular, irregularly shaped, foamed powder, etc., or fibrous.They may be single particles or granules, and the particle surface It may also have a crosslinking density gradient in the vicinity. In the case of powder, the weight average particle size is 10 to 1.0.
00 microns is good, preferably 100 to 700 microns.
It is in the micron range.

Examples of the hydrophilic fibers used in the present invention include wood pulp fibers such as mechanical pulp, chemical pulp, semi-chemical pulp, and dissolving pulp made from wood, and artificial cellulose fibers such as rayon and acetate. In the present invention, these hydrophilic fibers may also partially contain synthetic fibers such as nylon, polyester, and polyolefin. An example of a preferred hydrophilic fiber is wood pulp fiber. The hydrophilic fiber used is water-absorbing polymer 10
5 to 500 parts by weight per 0 parts by weight, preferably 10 to 20 parts by weight
It is in the range of 0 parts by weight.

In the present invention, synthetic pulp can also be used in combination with the hydrophilic fibers. The amount used is 10% of the water-absorbing polymer
The amount is 1 to 30 parts by weight per 0 parts by weight, preferably 2 to 25 parts by weight. The synthetic pulp used in the present invention is a pulp made from a thermoplastic resin, and is known per se. Examples of thermoplastic resins include polyolefin, polyester, polyacrylonitrile, and other hydrophobic thermoplastic resins, particularly polyethylene, polypropylene, ethylene-propylene copolymer, and ethylene-1-
Polyolefins made of one or more α-olefins such as butene copolymers, propylene-1-butene copolymers, and ethylene-4-methyl-1-pentene copolymers can significantly improve their hydrophilicity. Therefore, it is preferable. Methods for producing synthetic pulp from thermoplastic resins are disclosed in, for example, Japanese Patent Publication No. 47-21.898, Japanese Patent Publication No. 47-32,133, and Japanese Patent Publication No. 52-47.049.

For example, swp <manufactured by Mikata Petrochemical Co., Ltd.”)
and PULPEX (manufactured by Vercules).

The absorbent body of the present invention can be obtained, for example, by the following method.

(1) 100 parts by weight of water-absorbing polymer and 1 to 100 parts of synthetic pulp
These are mixed while adding 1 to 40 parts by weight of water to 30 parts by weight, and the resulting mixture is dry mixed with 5 to 500 parts by weight of hydrophilic fibers such as pulverized pulp to 100 parts by weight of the water-absorbing polymer. A method of obtaining an absorbent material with a density of 0.1 to 0.5 g/cm3 by heat compression after forming it into a web. (2) Wetting with 1 to 40 parts by weight of water to 100 parts by weight of the water-absorbing polymer. The resulting mixture was dry mixed with 100 parts by weight of the water-absorbing polymer and 5 to 500 parts by weight of hydrophilic fibers such as pulverized pulp, and formed into a web. After that, the density is 0.1 by heat compression.
~0. Examples of methods include a method for obtaining an absorbent material of 5 g/cm3.

The absorber thus obtained has a density of 0.1 to 0.5
g/cm3, preferably 0.15 to 0.4 g/cm3,
The absorption amount of physiological saline under pressure is in the range of 11 to 25 g/g, preferably 12 to 20 g/g, and the shedding rate of the water-absorbing polymer is 45% or less, preferably 30% or less. It was something.

In addition, by changing the mixing ratio variously, the absorption amount can be increased by 30%.
g/g or higher, but these are not preferred because they reduce the wet stability and absorption efficiency of the absorber for the reasons mentioned above. If the shedding rate of the water-absorbing polymer is greater than 45%, for example, when used in disposable diapers,
This is undesirable because the absorbent body is destroyed by the baby's movements when the diaper is put on, causing leakage. Absorption amount under pressure is 11g
If the amount is less than /g, the absorption capacity of the absorbent body is insufficient, so that the absorbent body cannot be made thinner and lighter, which is not preferable. Considering various points mentioned above, the absorbent property of the absorber has a density of 0.1 to 0.5 g.
/cf113, the absorption amount under pressure is in the range of 11 to 25 g/g, and the shedding rate of the water-absorbing polymer is 45% or less.

The absorbent body of the present invention that satisfies all the absorbent physical properties can be applied to an absorbent article by simply inserting it between a liquid-permeable sheet and a liquid-impermeable sheet, which are other components of the absorbent article. Alternatively, cotton pulp or a known absorbent material may be used in combination with the absorbent material of the present invention as an absorbent layer.

The liquid-impermeable sheet used in the present invention includes polyethylene, polypropylene, vinyl chloride resin, nylon,
There are sheets of soft synthetic resin such as vinylon, and liquid-permeable surface materials include, for example, natural fibers (e.g. wood or cotton fibers), synthetic fibers (e.g. polyester or polyolefin fibers), or combinations of natural fibers and synthetic fibers. non-woven fabric, apertured plastic film,
Examples include porous foam, reticulated foam, and the like.

The embodiments of the absorbent core and absorbent article of the present invention have been described above, but the embodiments are not limited to this description and can be modified as desired within the scope of the spirit thereof.

(Example) Examples will be described below. In addition, "1 part" in the following Reference Examples, Examples, and Comparative Examples is "2 parts" unless otherwise specified.

(performance test) The obtained absorber was evaluated by the following method.

1. Absorption amount under pressure As shown in Figure 1, from an inverted funnel 6 equipped with an outside air suction pipe 2 placed on a balance 1 and communicated with a 0.9% concentration physiological saline storage part through a conduit 5. Therefore, the reverse funnel 6
Using a device with a glass filter 7 attached to the top of the filter, an absorber 8 is placed on the filter 7, a weight 9 is placed on top of the absorber 8, and 30 g/c11 after 30 minutes! Absorption ffi (g/g) of the absorber under load was measured. In addition,
The absorbent material was previously cut into a circular shape with a diameter of 5.5 cm. 2. Absorbent density: 7g/C- for absorbent material cut into 10cm x 10cm pieces
The height z (mm) under load was measured, and the value obtained by dividing the polymerization x (g) of the absorber by its volume 10z (cm3) was taken as the density.

3. Shedding rate of water-absorbing polymer In a 100 cc beaker, the absorbent body cut into 2 cm x 4 cm was stirred in 100 cc of physiological saline (stirred at 100 rpm using a 45 mm stir bar).
I cast it. After 10 minutes of stirring, the absorbent body was taken out, the weight of the water-absorbing polymer that had fallen into the physiological saline was measured, and the amount of water-absorbing polymer that had fallen off was measured using the following formula.

Reference example 1 Sodium acrylate 74.98 mol%, acrylic acid 2
3 of the acrylate monomers consisting of 5 mol% and trimethylolpropane triacrylate, 0.02 mol%.
4.000 parts of a 7% aqueous solution was polymerized with 2.0 parts of sodium persulfate and 0.08 parts of I-ascorbic acid under stirring in a nitrogen atmosphere to obtain a gel-like hydrated polymer finely divided into particles of 5 mm in size. Obtained union. This gel-like water-containing polymer was heated to 150°C.
After drying with a hot air dryer, pulverize with a hammer type pulverizer,
The mixture was sieved through a 0-mesh wire mesh, and the material that passed through the 20-mesh mesh was collected (average particle size: 405 microns). Next, 100 fractions
After adding and mixing 0.5 parts of glycerin, 2 parts of water, and 2 parts of ethyl alcohol, the mixture was heat-treated at 210° C. to obtain a water-absorbing polymer A which was secondarily crosslinked near the surface. The amount of physiological saline absorbed by this product was 50 g/g.

Reference example 2 Sodium acrylate 74.95 mol% acrylic acid 25
37% of acrylate monomers consisting of mol% and 0.05 mol% of trimethylolpropane triacrylate
4,000 parts of an aqueous solution was polymerized with 2.0 parts of sodium persulfate and 0.08 parts of g-ascorbic acid under stirring in a nitrogen atmosphere to obtain a gel-like hydrous polymer finely divided into particles of 5 mm. Obtained. This gel-like water-containing polymer was dried in a hot air dryer at 150°C, then crushed in a hammer-type crusher, sieved through a 20-mesh wire mesh, and the material passing through the 20-mesh mesh was fractionated to obtain water-absorbing polymer B (average particle size 350 microns)
I got it. The amount of physiological saline absorbed by this product is 46 g/
It was g.

Reference Example 3 After adding and mixing 0.5 parts of glycerin, 2 parts of water, and 2 parts of ethyl alcohol to 100 parts of the water-absorbing polymer B obtained in Reference Example 2, heat treatment was performed at 210°C to cause secondary crosslinking near the surface. A water-absorbing polymer C was obtained. The amount of physiological saline absorbed by this product was 43 g/g.

Reference Example 4 Water absorbent polymer C obtained in Reference Example 3 was classified using a 60-100 mesh to separate water absorbent polymer D (particle size 250-149 microns). The amount of physiological saline absorbed by this product is 42
g/g.

Example 1 100 parts by weight of water-absorbing polymer A and 25 parts by weight of synthetic pulp (trade name: SWP rUL7415J, manufactured by Mikata Petrochemical Co., Ltd.) were mixed while adding 25 parts by weight of water. The mixture was then dry mixed with 125 parts by weight of pulverized pulp in a mixer and air-formed onto a wire screen using a batch-type air-forming device to form a sheet with dimensions of 14 cm x 40 cm.
cm, and the basis weight was 0.047 g/c♂. The resulting web was compressed and heated at 150°C for 10 minutes to reduce the density to 0.
．． An absorber (1) of the present invention weighing 16 g/cm 3 was obtained. The absorption amount under pressure of the obtained absorbent body (1) was 16. 5g
/g, and the shedding rate of the water-absorbing polymer was 19%.

Example 2 Same as Example 1 except that the amount of water was changed to 32 parts by weight, the amount of synthetic pulp was changed to 17 parts by weight, and the amount of crushed pulp was changed to 133 parts by weight, but the basis weight was 0°051 g/cIi
l, the absorber of the present invention having a density of 0.13 g/cm3 (2
) was obtained. The absorption capacity under pressure of the obtained absorbent body (2) was 16
．． 0 g/g, and the shedding rate of the water-absorbing polymer was 22%.

Example 3 To 100 parts by weight of water-absorbing polymer A, 7 parts by weight of synthetic pulp preliminarily moistened with 5 parts by weight of water were added and mixed. The mixture was dry mixed with 67 parts by weight of pulverized pulp in a mixer and air-formed onto a wire screen using a Bas-Sochi type air-forming device, measuring 14 cm x 40 cm.
The web had a basis weight of 0.042 g/C♂. The resulting web was compressed and heated at 150°C for 10 minutes to reduce the density to 0.
An absorber (3) of the present invention having a weight of 20 g/cm3 was obtained. The absorption amount under pressure of the obtained absorbent body (3) was 15.8 g/g, and the shedding rate of the water-absorbing polymer was 20%.

Example 4 100 parts by weight of water-absorbing polymer and synthetic pulp (product name: SWP rUL-415J: Mikata Petrochemical Co., Ltd.)
13 parts by weight (manufactured by ) were mixed while adding 20 parts by weight of water. The mixture was then dry mixed with 100 parts by weight of pulverized pulp in a mixer and air-formed onto a wire screen using a batch-type air-forming device to form a sheet with dimensions of 14 cm x 4 C1.
cm web.

The top and bottom surfaces of the obtained web are tsubo! It was sandwiched between 0.0013g/cJ tissue paper and then embossed at 150°C for 1 minute to give a tsubo m of 0.054g/c♂ and a density of 0.
．． An absorber (4) of the present invention having a weight of 27 g/cm3 was obtained. The absorption amount under pressure of the obtained absorbent body (4) was 14.4 g/g, and the shedding rate of the water-absorbing polymer was 6%.

Example 5 Same as Example 4 except that the amount of pulverized pulp was changed to 66 parts by weight, basis weight 0.044 g/cd, density 0°22 g/c
An absorber (5) of the present invention of m3 was obtained. The obtained absorber (
The absorption amount under pressure of 5) is 17.3 g/g.

The rate of shedding of the water-absorbing polymer was 7%.

Example 6 The amount of synthetic pulp was 15 parts by weight, and the amount of pulverized pulp was 3 parts by weight.
The basis weight was 0.0 in the same manner as in Example 4 except that 4 polymerized parts were used.
An absorbent body (6) of the present invention having a density of 29 g/crI and a density of 0.30 g/cm3 was obtained. The absorption amount under pressure of the obtained absorbent body (6) was 16.3 g/g, and the shedding rate of the water-absorbing polymer was 19%.

Example 7 100 parts by weight of water-absorbing polymer and synthetic pulp (product name: SWP rUL-415J: Mikata Petrochemical Co., Ltd.)
12 parts by weight (manufactured by M.D.) were mixed with 20 parts by weight of water. The mixture was then dry mixed with 131 parts by weight of pulverized pulp in a mixer and air-formed onto a wire screen using a batch-type air-forming device to form a sheet with dimensions of 14 cm x 40 cm.
A web of m is used. The upper and lower surfaces of the obtained web are tsubo ff1
0. The absorbent material (7) of the present invention having a basis weight of 0.047 g/cm2 and a density of 0.24 g/cm3 was obtained by sandwiching between 0.0013 g/cm2 tissue paper and then embossing press at 150 DEG C. for 1 minute. The absorption amount under pressure of the obtained absorbent body (7) was 12.5 g/g, and the shedding rate of the water-absorbing polymer was 8%.

Example 8 The amount of synthetic pulp was 5 parts by weight, and the amount of crushed pulp was 10 parts by weight.
The basis weight was 0.0 in the same manner as in Example 7 except that the basis weight was 0.0 parts by weight.
An absorbent body (8) of the present invention having a weight of 50 g/cm 2 and a density of 0.25 g/cm 3 was obtained. The absorption amount under pressure of the obtained absorbent body (8) was 15.3 g/g, and the shedding rate of the water-absorbing polymer was 13%.

Example 9 The width of the synthetic pulp was set to 23 layers, and the output of the crushed pulp was set to 1.
Same as Example 7 except that the basis weight was 33 parts by weight.
An absorbent body (9) of the present invention having a density of 0.060 g/cm 2 and a density of 0.30 g/cm 3 was obtained. The obtained absorbent body (9) had an absorption capacity under pressure of 13.5 g/g.

The rate of shedding of the water-absorbing polymer was 12%.

Example 10 The amount of synthetic pulp was 24 parts by weight, and the amount of pulverized pulp was 1
Same as Example 7 except that the basis weight was 67 parts by weight.
An absorbent body (10) of the present invention having a density of 0.070 g/cm 2 and a density of 0.35 g/cm 3 was obtained. The amount of absorption under pressure of the obtained absorbent material 10) was 12.3 g/g, and the shedding rate of the water-absorbing polymer was 1.
It was 5%.

Example 11 Same as Example 9 except that the amount of pulverized pulp was changed to 67 parts by weight, but the basis weight was 0.044 g/cm2 and the density was 0.33 g.
An absorbent body (11) of the present invention having a particle size of 1/cm3 was obtained. The absorbency of the obtained absorbent body (11) under pressure was 14.2 g/g, and the shedding rate of the water-absorbing polymer was 10%.

Example 12 100 parts by weight of water-absorbing polymer D and 13 parts by weight of synthetic pulp (trade name: SWP rUL-415J: manufactured by Mikata Petrochemical Co., Ltd.) were added to 30% by weight of polyaluminum chloride.
The mixture was mixed while adding 20 parts by weight of the aqueous solution. The mixture was then dry mixed with 100 parts by weight of pulverized pulp in a mixer and air formed onto a wire screen using a batch air forming apparatus into a web measuring 14 cm x 40 cm. The upper and lower surfaces of the obtained web have a basis weight of 0.0013 g/c.
Sandwiched with m2 tissue paper and then embossed at 150℃ for 1 minute to give a final shape of 0.42g/cm.
2. Absorbent material of the present invention with a density of 0.21 g/cm3 (12
) was obtained. The absorption amount under pressure of the obtained absorber (12) is 1
3.2 g/g, and the shedding rate of the water-absorbing polymer was 5%.

Example 13 100 parts by weight of water-absorbing polymer B and synthetic pulp (product name: SWP rUL-415J: Mikata Petrochemical Co., Ltd.)
13 parts by weight of ethylene glycol diglycidyl ether (manufactured by Nagashio Kasei Co., Ltd.: Bunacol EX-810) were mixed with all 20 parts by weight of a 1% aqueous solution of 1% aqueous solution. The mixture was then dry mixed with 67 fg of ground pulp in a mixer and air formed onto a wire screen using a batch type air forming apparatus into a web measuring 14 cm x 40 cm. The upper and lower surfaces of the obtained web have a basis weight of 0.0013 g.
/Cm2 tissue paper, then 150cm
Emboss press at ℃ for 1 minute, basis weight 0.047g/c
m2, density of 0.23 g/Cm3 of the present invention (1
3) was obtained. The absorbent body (13) thus obtained had a pressurizer absorption amount of 13.7 g/g and a drop-off rate of the water-absorbing polymer of 3%.

Example 14 In the same manner as in Example 8, except that the amount of synthetic pulp was changed to 7 parts by weight, a tsubo ff10. 043g/c
absorber of the present invention (14 m2, density 0.22 g/cm3)
) was obtained. The pressurizer absorption capacity of the obtained absorber (14) is 1
5.3 g/g, and the shedding rate of the water-absorbing polymer was 14%.

Example 15 100 parts by weight of water-absorbing polymer and synthetic pulp (product name: SWP rUL-415J: Mikata Petrochemical Co., Ltd.)
13 parts by weight (manufactured by ) were mixed while adding 20 parts by weight of water. The mixture was then dry mixed with 100 parts by weight of pulverized pulp in a mixer and air-formed onto a wire screen using a batch-type air-forming device to form a sheet with dimensions of 14 cm x 40 cm.
A web of m is used. The upper and lower surfaces of the obtained web have a basis weight of 0.
Sandwiched between 0.02g/cm2 tissue paper and then embossed at 200℃ for 10 seconds to obtain a paper with a basis weight of 0.0.
An absorbent body (15) of the present invention having a weight of 52 g/cm 2 and a density of 0.26 g/cm 3 was obtained. The absorption rate under pressure of the obtained absorbent body (15) was 14.5 g/g, and the shedding rate of the water-absorbing polymer was 1.
It was 1%.

Example 16 100 parts by weight of water-absorbing polymer C and synthetic pulp (product name: SWP rUL-415J: Mikata Petrochemical Co., Ltd.)
10 parts by weight of 20 parts by weight of water were added. The mixture was then dry mixed with 133 parts by weight of pulverized pulp in a mixer and air-formed onto a wire screen using a batch-type air-forming device to form a sheet with dimensions of 14 cm x 40 cm.
A web of m is used. The upper and lower surfaces of the obtained web have a basis weight of 0.
Sandwiched between 0.02g/cm2 tissue paper and then embossed at 150°C for 10 minutes to obtain a paper with a basis weight of 0.0.
An absorbent body (16) of the present invention having a density of 92 g/cm2 and a density of 0.23 g/cm3 was obtained. The absorber (16) obtained had an absorption amount of 13.5 g/g and a drop rate of the water-absorbing polymer of 29.
%Met.

Example 17 100 parts by weight of water-absorbing polymer A and 8 parts by weight of synthetic pulp were mixed while adding 20 parts by weight of water.

The mixture was dry mixed with 70 parts by weight of ground pulp in a mixer and then air formed into a web on a wire mesh screen. Separately, a web consisting of 35 parts by weight of pulverized pulp and 0.7 parts by weight of synthetic pulp was prepared, and both sides of the web were sandwiched between two sheets of this web.
A web with a thickness of 0 cm and a basis weight of 0°046 g/cm2 was prepared. The obtained web was held between embossing hot presses and heated at 150° C. for 1 minute to obtain an absorbent body (17) of the present invention having a density of 0.23 g/cm 3 . The obtained absorber (17) had a pressurizer absorption amount of 13.5 g/g, and a water-absorbing polymer shedding rate of 20
%Met.

Example 18 100 parts by weight of water-absorbing polymer D and 20 parts by weight of synthetic pulp were mixed while adding 20 parts by weight of water. The mixture was dry mixed with 18 parts by weight of ground pulp and then air formed into a web on a wire mesh screen. This material was sandwiched between tissues with a basis weight of 0.0013/cm2, and then embossed at 150°C for 1 minute.
, 019 g/cm2 and a density of 0.25 g/cm3, an absorbent body (18) of the present invention was obtained. The absorbent group under pressure of the obtained absorbent body (18) was 18.0 g/g, and the shedding rate of the absorbent polymer was 35%.

Example 19 100 parts by weight of water-absorbing polymer A and synthetic pulp (trade name: SWP l [L-415J: Mikata Petrochemical Co., Ltd.)
13 parts by weight (manufactured by ) were mixed while adding 10 parts by weight of water. The mixture was then sandwiched between two webs made of 33 parts by weight of pulverized pulp to form a web with dimensions of 14 cm x 40 cm and basis weight of 0.052 g/cm 2 . The obtained web was sandwiched between embossing hot presses and heated at 150°C for 1 minute to obtain an absorbent material of the present invention (19
) was obtained. The absorbent teeth on the pressurization of the obtained absorbent body (19) are 1
2.5 g/g, and the shedding rate of the water-absorbing polymer was 33%.

Example 20 100 parts by weight of water-absorbing polymer C and synthetic pulp (product name: SWP rUL-415J: Mikata Petrochemical Co., Ltd.)
20 parts by weight of 20 parts by weight of water were added. The mixture was then dry mixed with 60 parts by weight of pulverized pulp in a mixer and air-formed onto a wire screen using a batch-type air-forming device to form a sheet with dimensions of 14 cm x 40 cm.
It was made into a web. Then, one side of the web is coated with 3 pieces of crushed pulp.
A web consisting of 0 parts by weight was placed, and the upper and lower surfaces of the obtained web were sandwiched between tissues having a basis weight of 0.0013 g/cm2, and then the web was passed between heated rollers for a second time of 20 parts by weight.
Heated at 0℃ for 20 seconds, basis weight 0.048g/Cm2
, an absorbent body (20) of the present invention having a density of 0.16 g/cm3 was obtained. The pressurizer absorption capacity of the obtained absorber (20) was 12.
2g/g, and the shedding rate of the water-absorbing polymer was 14%.

Comparative Example 1 1'00 parts by weight of water-absorbing polymer C1 and 33 parts by weight of synthetic pulp (trade name: SWP rUL-415J, manufactured by Mikata Petrochemical Co., Ltd.) were mixed while adding 20 parts by weight of water. The mixture was then dry mixed with 100 parts by weight of pulverized pulp in a mixer and air-formed onto a wire screen using a batch-type air-forming device to form a sheet with dimensions of 14 cm x 40 cm.
cm web.

The upper and lower surfaces of the obtained web are tsubo fik0.0013g/c
Clamped with IIY tissue paper, then heated to 150℃
Embossing press for 1 minute, basis weight 0.048g/c!
A comparative absorbent material (1) having a density of 0.24 g/cm3 was obtained. The pressurizer absorption amount of the obtained comparative absorber (1) was 10.2 g.
/g, and the shedding rate of the water-absorbing polymer was 17%.

Comparative Example 2 100 parts by weight of water-absorbing polymer C and synthetic pulp (product name: SWP rUL-415J: Mikata Petrochemical Co., Ltd.)
20 parts by weight of water were added to the mixture. The mixture was then dry mixed with 100 parts by weight of pulverized pulp in a mixer, and air-formed onto a wire screen using a batch-type air-forming device to form a sheet with dimensions of 14 cm x 4.
The web was 0 cm.

The upper and lower surfaces of the obtained web are tsubo 10.0013 g/c.
Clamped with tlI tissue paper, then heated at 150°C.
Emboss press for 1 minute with tsubo ff10.056g
/ cIll, comparative absorber with density 0.28 g/cm3 (
1) was obtained. The obtained comparative absorbent body (1) had a pressurizer absorption amount of 8.8 g/g and a drop-off rate of the water-absorbing polymer of 5%.

Comparative Example 3 100 parts by weight of water-absorbing polymer and 100 parts by weight of pulverized pulp were dry mixed in a mixer, and then air-formed on a wire screen using a batch-type air-forming device.
The web had dimensions of 14 cm x 40 cm. The upper and lower surfaces of the obtained web were sandwiched between tissue papers with a basis weight of 0.0013 g/crI, and then emboss-pressed at 150°C for 1 minute to obtain a paper with a basis weight of 0.043 g/cIil and a density of 0.17.
A comparative absorbent material (3) of g/cm3 was obtained.The obtained comparative absorbent material (3) had an absorption amount of 12.3 g/g and a drop-off rate of the water-absorbing polymer of 76%.

Comparative Example 4 100 parts by weight of water-absorbing polymer C, synthetic pulp (rUL41
5J) and 100 parts by weight of ground pulp were dry mixed in a mixer and then air-formed onto a wire screen using a batch-type air-forming device to obtain a size of 1.
The web was 4 cm x 40 cm. The upper and lower surfaces of the obtained web were sandwiched between tissue paper with a basis weight of 0.0013 g/c♂, and then embossed at 150°C for 1 minute to give a basis weight of 0.049 g/c♂ and a density of 0.25 g/c♂.
A comparative absorber (4) of cm3 was obtained. The obtained comparative absorbent body (4) had a pressurizer absorption amount of 10.9 g/g and a drop-off rate of the water-absorbing polymer of 53%.

Comparative Example 5 100 parts by weight of water-absorbing polymer C and synthetic pulp (product name: SWP rUL-415J: Mikata Petrochemical Co., Ltd.)
13 parts by weight (manufactured by ) were mixed while adding 20 parts by weight of water. The mixture was then dry mixed with 100 parts by weight of ground pulp in a mixer and air-formed onto a wire screen using a batch-type air-forming device, with dimensions 14 cm x
A 40 cm web was used.

The upper and lower surfaces of the obtained web were sandwiched between tissue paper with a tsubo fi of 13 g/m2, and then heated at 150°C for 10 minutes to give a basis weight of 0.050 g/cIil and a density of 0°08 g/m2.
A comparative absorber (5) of cm3 was obtained. The obtained comparative absorbent body (5) had an absorption amount under pressure of 13.9 g/g.

The rate of shedding of the water-absorbing polymer was 56%.

Example 21 Consisting of a liquid-permeable polypropylene top sheet, two pieces of tissue paper, the absorbent body (1) of the present invention cut into 9 cm x 35 cm (weight FF 115 g), a liquid-impermeable polyethylene back sheet containing leg gears, and two tape fasteners. The disposable diapers were assembled by hand by fastening the individual components with double-sided tape. The total weight of the diaper was 33g.

The obtained diaper was worn on a 1-year-old child (weight 10 kg) and compared with diapers currently on the market (total weight 50 g).The diaper using the absorbent material of the present invention showed superior shape retention after urine absorption. It was extremely good and there was little leakage.

Example 22 Disposable diapers using absorbers having various properties were made in the same manner as in Example 21.

These diapers were tested by a panel of seven mothers for approximately - months. Each panelist randomly received and tested 30 diapers. After the test, each diaper was collected and the leakage rate and shape retention of the absorbent body were compared. Results first
Shown in the table. It can be seen that the absorbent article using the absorbent body of the present invention has excellent absorption properties.

(Effects of the Invention) Since the absorbent body obtained by the present invention has the above configuration, it can be used in absorbent articles in the medical impact field such as sanitary napkins, disposable diapers, incontinence pads, breast milk pads, and medical pads. Ideal for absorbers. It can also be used in various applications that require water retention and absorption, such as freshness preservation materials, water retention materials for agriculture and horticulture, and industrial water absorption materials.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of the pressurized absorption measuring device used in the present invention. Patent applicant: Agent of Nippon Shokubai Chemical Co., Ltd.

Claims (5)

[Claims] (1) An absorbent body mainly composed of a water-absorbing polymer and a hydrophilic fiber, the absorbent body having a density of 0.1 to 0.5 g/cm
^3, Absorption amount under pressure for physiological saline is 11-25g
/g, and the shedding rate of the water-absorbing polymer is 45
% or less. (2) The absorbent body according to claim 1, wherein the water-absorbing polymer is a crosslinked polymer of a water-soluble ethylenic monomer containing acrylic acid or an acrylate as a main component. (3) The absorbent body according to claim 1, wherein the amount of hydrophilic fibers is in the range of 5 to 500 parts by weight per 100 parts by weight of the water-absorbing polymer. (4) The absorbent body according to claim 3, further comprising 1 to 30 parts by weight of synthetic pulp per 100 parts by weight of the water-absorbing polymer. (5) An absorbent article comprising a liquid-permeable surface material, a liquid-impermeable backing material, and an absorbent layer sandwiched between them, wherein a part or all of the absorbent layer is defined in claims 1 to 4. An absorbent article characterized by being an absorbent body.