JP2918808B2 - Absorber and an absorbent article - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION This invention is, for example, a paper diaper (disposable diaper), sanitary napkins, absorbent suitably used for sanitary materials called incontinent pads and the like, and to a absorbent article.

[0002]

In recent years, disposable diapers, sanitary napkins, the sanitary materials called incontinent pads and the like, as a constituent material,
Water-absorbent resin for the purpose of to absorb body fluids are widely used.

[0003] Examples of the water-absorbent resin, for example, partially neutralized polyacrylic acid cross-linked (JP 55-84304, JP-
JP 55-108407, JP Sho 55-133413 JP)
Starch - acrylonitrile graft polymer hydrolyzate (JP 46-43995 JP), starch - neutralized product of acrylic acid graft polymer (JP 51-125468 JP), vinyl acetate - acrylic acid ester copolymers polymer of saponification product (JP-a-52
-14689 discloses), acrylonitrile copolymer or acrylamide copolymer hydrolyzate (JP 53-15959 JP) or a cross-linked product thereof, cross-linked cationic monomer (Japanese 58-154709 JP , JP 58-154710 JP), and the like.

[0004] The properties to be provided the above water-absorbent resin, excellent water absorption and water absorption rate when in contact with aqueous liquids such as body fluids, gel strength, suction force or the like to suck water from a substrate containing aqueous liquid and the like. Then, conventionally, it combines a plurality of these properties, when used for sanitary materials such as paper diapers and sanitary napkins, the water absorbent resin exhibits excellent performance (absorption properties), or using a water-absorbent resin absorber and absorbent article have been proposed.

[0005] The above conventional water-absorbent resins, or as the absorber and an absorbent article using the water-absorbent resin, for example, a specific gel capacity and shear modulus, extractable polymer content of the combined water-absorbent resin (U.S. Patent No. 4,654,039), water absorption and water absorption rate, the specified water-absorbing resin gel strength, and paper diapers and sanitary napkins using the water absorbent resin (JP-60
-185,550 JP, JP-A-60-185551, JP-Sho 60-1
85804 JP), specific water absorption and water absorption speed, paper diapers using water-absorbent resin having a gel stability (JP 60-18580
5 JP), water absorption and suction force, the water-soluble content absorbent article arranged identified absorbent resin (JP-63-21902 JP), water absorption of the water absorption and under pressure, gel breaking absorbent hygiene articles containing a specific water-absorbent resin strength (JP 63-998
61 No.), the paper diaper containing a specific water-absorbent resin absorption rate of water absorption and under pressure (Japanese Patent Laid-Open No. 2-34167),
Water absorption and under pressure, the particle size water-absorbing agent containing a specific water-absorbent resin (EP 339,461), a specific amount of a specific water-absorbent resin water absorption amount under pressure in absorption rate or a short time above containing that water-absorbing agent (EP 443,627), water-absorbing composite material specific water-absorbent resin deformation and the wicking index under load contains more than a certain amount (EP 532,002) are known.

[0006] In recent years, sanitary materials such as paper diapers and sanitary napkins, advances high functionality and thinner, the amount of the water-absorbent resin per sheet sanitary material, or predominantly water-absorbent resin and hydrophilic wt% of the water-absorbent resin in the absorbent body consisting of a sex fibers (hereinafter referred to as resin concentration) in increase trend. In other words, to reduce the small hydrophilic fiber bulk density,
Excellent water absorption, and, by increasing the high water-absorbent resin bulk density, increasing the ratio of the water-absorbent resin in the absorbent body, thereby working to the sanitary material thinner without decreasing an amount of water absorption.

[0007]

[SUMMARY OF THE INVENTION However, the present inventors have found to increase the water absorption of the sanitary materials such result of various investigations to increase the resin concentration in the absorbent body, higher resin concentration than conventional using the absorber,
And, to prevent a disadvantage such as leakage of the aqueous liquid from the sanitary materials, the above-mentioned water absorption and water absorption speed, gel strength, it is only by controlling the characteristic of the suction force and the like insufficient was found. For example, problems in recent years, especially in being noticed, under pressure of the water absorption only very large water-absorbent resin, the higher the resin concentration, that phenomenon such as the liquid diffusibility in the absorber decreases extremely occurs It has a point.

Further, the present inventors as a result of various studies in view of the water absorption characteristics than conventional high resin concentration absorber, the absorber a mixture prepared by mixing a known water-absorbent resin and hydrophilic fibers when used as, but when the resin concentration is low shows the absorption properties of a certain level, resin concentration 40% by weight
Above the liquid diffusibility decreases rapidly, the water absorption amount per unit weight of the absorbent body is found to decrease. That is, when using a mixture obtained by mixing a known water-absorbent resin and hydrophilic fibers as an absorber, so that the above problem arises.

It is therefore an object of the present invention is to solve the problems described above, for example, when used for sanitary materials, even by increasing the resin concentration of the water-absorbent resin, always very high liquid-diffusivity and excellent performance water-absorbent resin can exhibit (water absorption properties), the absorption body such as to hold the water absorption, and is to provide an absorbent article.

[0010]

Means for Solving the Problems The present inventors have found that in order to achieve the above object, the water-absorbing resin, a result of intensive studies for absorber and absorbent article, to synthesize a certain water-absorbing resin precursor , heat treatment of the water-absorbing resin precursor in the presence of a particular surface crosslinking agent, water-absorbent resin obtained by the production method of, i.e., the absorber and absorbent article comprising a water-absorbent resin, the above conventional water-absorbing resin is not provided with excellent performance (water absorption properties), i.e., and when the amount of the water absorbent resin is large, even if the resin concentration is high, such as to retain a very high liquid-diffusivity and the water absorption It found that has an excellent performance, and have completed the present invention.

[0011] That is, the absorber of the first aspect of the present invention, in order to solve the above problems, the diffusing absorbency after 60 minutes from the absorption initiation is 25 g / g or more water-absorbing resin 40 wt% It is characterized in that it comprises more.

[0012] absorber of the invention of claim 2, wherein, in order to solve the above problems, there is provided an absorbent body according to claim 1, wherein,
Diffusing absorbency of 30 minutes after the absorption initiation of the water absorbent resin
It is characterized in that it is 15 g / g or more.

[0013] absorber of the invention of claim 3, wherein, in order to solve the above problems, there is provided an absorbent body according to claim 1 or 2, wherein the hydrophilic fibers, the water-absorbent resin and the hydrophilic fibers the amount of the water-absorbent resin to the total amount is characterized in that less than 50% by weight.

[0014] The absorbent article of the invention of claim 4, wherein, in order to solve the above problems, an absorbent layer comprising an absorbent body according to any one of the claims 1 to 3, a liquid-permeable a sheet having, are characterized by being sandwiched between the sheet having a liquid-impervious.

The water absorbing resin of the invention of claim 5, wherein, in order to solve the above problems, diffusing absorbency of 30 minutes after the absorption initiation is not less 15 g / g or more, and, after 60 minutes diffusion absorption capacity is characterized in that it is 25 g / g or more.

The water absorbing resin of the invention of claim 6, wherein, in order to solve the above problems, diffusing absorbency after 20 minutes from the absorption initiation is not less 15 g / g or more, and, after 60 minutes diffusion it is characterized in that the absorption capacity is 30 g / g or more.

The production process for a water-absorbent resin of the invention according to claim 7, in order to solve the above problems, an average particle size of 200μ
Within the scope of m to 600 .mu.m, a particle size ratio of 5 wt% or less of particles less than 106 [mu] m, the water-absorbing resin precursor having a carboxyl group, capable of reacting with the carboxyl group, the solubility parameter is 12.5 (cal / cm ^{3) 1/2} or more first surface crosslinking agent,
And, by a solubility parameter of the heat treatment in the presence of 12.5 (cal / cm ^{3) 1/2} than the second surface-crosslinking agent, absorption
Water diffusing absorbency of 60 minutes after the start is 25 g / g or more
It is characterized by obtaining a sexual resin.

[0018] the present invention will be described in detail below. The diffusing absorbency in the present invention, the basis weight of the water-absorbent resin is high and, in consideration of the diffusion force of the aqueous liquid in a state where each other resin particles are in close contact by an external force, in order to evaluate the water absorption amount of the absorbent body of a novel physical properties. Diffusing absorbency described above, in the measurement of a predetermined condition, after a predetermined from the absorption initiation time, for example, is calculated from the measured value after 60 minutes. Diffusion absorption
It will be described in detail method of measuring the magnification.

[0019] (a) diffusing absorbency First, the measurement device used for measuring the diffusing absorbency,
With reference to FIGS. 1 and 2, briefly described below.

As shown in FIG. 1, the measuring device, the balance 1
When a container 2 of the placed a predetermined capacity on the balance 1, an air-inhaling pipe 3, a conduit 4, a glass filter 6, taken from the placed on the glass filter 6 has been measured portion 5 which there. Container 2 above, an opening 2a at its top, has respectively an opening 2b at its side portions, the opening 2
While external air intake pipe 3 is fitted to a, the conduit 4 is attached to the opening 2b. Further, the container 2, filled with a predetermined quantity of saline 12. The lower end of the air-inhaling pipe 3 is submerged in the saline 12. Glass filter 6 mentioned above is formed with a diameter 70 mm. And,
Container 2 and the glass filter 6 communicate with each other by a conduit 4. The glass filter 6 is fixed to only slightly higher position relative to the lower end of the air-inhaling pipe 3.

As shown in FIG. 2, the measurement section 5 described above, the filter paper 7, a seat 8, chromatic and supporting cylinder 9, and attached to the wire mesh 10 at the bottom of the supporting cylinder 9, and a weight 11 are doing. The measurement unit 5, on the glass filter 6, the filter paper 7, the sheet 8, the supporting cylinder 9 (i.e., metal gauze 10) with is placed in this order, the internal supporting cylinder 9, namely, wire mesh 1
0 weight 11 on top is made is placed. Sheet 8,
Made of polyethylene terephthalate (PET), and is formed in a donut shape having a thickness of 0.1mm with an opening diameter of 18mm in the central portion. Supporting cylinder 9 is formed on the inner diameter 60 mm. Wire gauze 10 is made of stainless steel and formed in 400 mesh (mesh size: 38 [mu] m). And, so that a predetermined amount of the water-absorbent resin on the wire net 10 is uniformly sprayed. Weight 11 is a wire mesh 10, that is, water-absorbent resin, so that it can apply a load of 20 g / cm ² uniformly, its weight is adjusted.

[0022] was measured diffusing absorbency using the measurement device with the above structure. It will be described below measurement method.

[0023] First, place the predetermined amount of saline 12 in the container 2, fitting the air-inhaling pipe 3 to the container 2, it performs a predetermined preparation operation and the like. Next, placing a filter paper 7 on the glass filter 6, the sheet 8 on the filter paper 7, the opening portion is placed so as to be positioned in the center of the glass filter 6. On the other hand, in parallel with these mounting 置動 operation, the internal supporting cylinder 9, namely, the water-absorbent resin 1.5 g (preferably on a wire mesh 10, by the operation such as classification, the water-absorbent resin was preconditioned particle size 300Myuemu～ 500 [mu] m the 1.5g) uniformly spraying, placing the weight 11 on the water-absorbing resin.

[0024] Then, on the sheet 8, a wire mesh 10, i.e., the supporting cylinder 9 was placed on the water-absorbent resin and the weight 11, the center portion is placed so as to coincide with the center of the glass filter 6 .

[0025] Then, from the point of placing the supporting cylinder 9 on the seat 8, 20 minutes, 30 minutes, or saline 12 water-absorbent resin has water absorption for 60 minutes the weight W
₂ (g), was measured using a balance 1. As shown in FIG. 3, the saline 12 is passed through the opening of the seat 8, while almost uniformly diffused in the lateral direction of the water-absorbent resin,
It is absorbed by the water absorbent resin.

[0026] Then, the weight W ₂ of the above, the following equation, according to the weight of the diffusing absorbency (g / g) = Weight W ₂ (g) / water-absorbent resin (g), 20 minutes after the water started 30 minutes after, or to calculate the diffusing absorbency after 60 minutes (g / g).

[0027] The diffusing absorbency, it is possible to evaluate the new properties of the water-absorbing resin. That is, by the diffusing absorbency, the water absorbent resin is a water-based liquid resin layer direction (hereinafter, lateral and referred) to what extent uniform or can be quickly diffused and actually how the whole water-absorbent resin it is possible to evaluate whether and a water absorption amount. Liquid diffusibility in the lateral direction of the aqueous liquid (liquid distribution capacity and liquid transfer capacity), in terms of a large amount of absorbed aqueous liquid, is a particularly important factor. Then, from the result of the evaluation, for example, mainly absorber comprising a water absorbent resin and a hydrophilic fiber, in particular, weight percent of the water-absorbing resin (hereinafter, referred to as resin concentration) of the water-absorbent resin in the high absorber the water absorption behavior can be easily predicted. It will be described later configuration of the absorber.

[0028] Incidentally, in the prior application described above, the literature to evaluate the amount of water absorption under pressure seen many. However, conventional evaluation of absorbing water, the direction perpendicular to the resin layer direction (hereinafter, referred to as longitudinal direction) only it is performed for. Thus, for either an aqueous liquid to how uniformly and quickly diffuse laterally, poorly evaluated. Thus, the above results of conventional evaluation, for example, in the paper diaper resin concentration with high absorption and the like, it is impossible to accurately predict the water absorption behavior of the absorbent body.

The absorber of the present invention, the diffusing absorbency after 60 minutes from the absorption initiation is 25 g / g or more water-absorbing resin 40 wt%
Or more, more preferably 50 wt% or more, more preferably
60 wt% or more, and most preferably contains 70 wt% or more. Diffusing absorbency after 60 minutes from the absorption initiation is 25 g / g less than the water-absorbent resin are inferior lateral liquid diffusibility in the high resin concentration (high concentration) absorber, the absorption capacity of the absorber smaller. Diffusing absorbency after 60 minutes from the absorption initiation is 28
g / g or more preferably, 30 g / g or more, and most preferably at least 32 g / g. In addition, diffusion absorption capacity
Also contain 25 g / g or more of the water-absorbent resin, the rate is 40
Absorber is less than wt%, the effect is in some cases difficult to remarkably appear. In the present invention, the diffusion absorption capacity, in the measurement of a predetermined condition, but is defined by the measured value after a predetermined time from the absorption start, in addition to the diffusing absorbency above, further, after 20 minutes from the absorption initiation or diffusing absorbency calculated from the measured value after 30 minutes and more preferably 15 g / g or more water-absorbing resin.

[0030] That is, the water-absorbent resin is diffusing absorbency of 30 minutes after the absorption initiation is at 15 g / g or more, more preferably diffusing absorbency after 60 minutes is 25 g / g or more , diffusing absorbency after 20 minutes from the absorption initiation is at 15 g / g or more,
And, still more preferably diffusing absorbency after 60 minutes is 25 g / g or more, diffusing absorbency after 20 minutes from the absorption initiation
15 is a g / g or more, and diffusing absorbency after 60 minutes 28 g
/ More preferably not g or more, diffusing absorbency after 20 minutes from the absorption initiation is at 15 g / g or more, and most preferably diffusing absorbency after 60 minutes is 30 g / g or more . Diffusing absorbency of 30 minutes after the absorption start 15 g / g less than the water-absorbent resin are inferior lateral liquid diffusibility, which may lead to a decrease in absorption capacity of the absorbent body.

The absorber of the present invention, in addition to the water-absorbing resin may contain hydrophilic fibers as necessary. When the absorber is made of, for example, water-absorbent resin and hydrophilic fibers, the structure of the absorbent body, for example, configured by uniformly mixing the water-absorbent resin and hydrophilic fiber, hydrophilic formed in layers structure which sandwiches absorbent resin between the fibers, by uniformly mixing the water-absorbent resin and hydrophilic fibers is formed into a layer, thereon, formed by laminating the hydrophilic fibers formed into a layer, the water absorbing resin and hydrophilic fibers homogeneously mixed and formed into a layer, and this,
Configuration or the like which sandwiches absorbent resin between the hydrophilic fibers in layers and the like. Furthermore, the absorbent body may have a configuration obtained by forming a water-absorbent resin into a sheet by incorporating a specific amount of water with respect to the water-absorbing resin. still,
Structure of the absorbent body is not limited to the configuration exemplified above.

[0032] As the hydrophilic fibers, for example, mechanical pulp or chemical pulp obtained from wood, semi-chemical pulp, cellulose fibers such as dissolved pulp, rayon, artificial cellulose fibers such as acetate. Among the above-exemplified fibers, cellulose fibers are preferable. Also, hydrophilic fibers, polyamide or polyester,
It may contain synthetic fibers such as polyolefins.
Incidentally, the hydrophilic fibers is not limited to the fibers of the examples.

[0033] Among the above illustrated construction, more preferably uniformly mixed with the structures and the water-absorbent resin and a hydrophilic fiber as the ratio of the water-absorbent resin is 40 wt% or more in the absorber, the water absorbing resin the amount of the water-absorbent resin to the total amount of the hydrophilic fiber is 50 wt% or more, preferably 60 wt% or more, more preferably such that 70 wt% or more, and these water-absorbent resin and hydrophilic fibers uniformly mixed structure is more preferable. With these configurations, the absorbent body can sufficiently exhibit its water absorption properties. Incidentally, the higher the resin concentration in the absorbent body, characteristics of the absorber of the present invention is remarkable.

Further, when the ratio of the hydrophilic fibers in the absorbent body is relatively small, the absorbent body using an adhesive binder, i.e., may be bonded to the hydrophilic fibers. By adhering the hydrophilic fibers, it is possible to enhance the strength and shape retention of the absorber during use or before use of the absorbent body.

[0035] As the adhesive binder include polyethylene, polypropylene, ethylene - propylene copolymer, 1-butene - emulsion or the like having a heat fusion fiber and adhesive polyolefin fibers such as ethylene copolymer may be exemplified . These adhesive binders may be used alone or may be used as a mixture of two or more. The weight ratio of the hydrophilic fiber and the adhesive binder is 50/50 to 99
/ Preferably within 1, more preferably in a range of 70 / 30-95 / 5, more preferably in the range of 80 / 20-95 / 5.

The water-absorbent resin in the present invention can be synthesized certain water-absorbing resin precursor, heat treatment of the water-absorbing resin precursor in the presence of a particular surface crosslinking agent, by the method of It is. The above water-absorbent resin precursor, within an average particle size of 200Myuemu～600 [mu] m, moreover, the particle size 1
Ratio of 06μm of less than particles is 10 wt% or less, and,
A resin having a carboxyl group to form a hydrogel by absorbing large amounts of water. Water-absorbing resin precursor is synthesized, for example, by aqueous solution polymerization. The water-absorbing resin precursor, specifically, for example, partially neutralized polyacrylic acid crosslinked starch - hydrolysates of acrylonitrile graft polymer, starch - neutralized product of acrylic acid graft polymer, acetate vinyl - saponified acrylic acid ester copolymer, acrylonitrile copolymer or hydrolyzed acrylamide copolymer or a cross-linked product thereof, a carboxyl group-containing crosslinked polyvinyl alcohol-modified, crosslinked isobutylene - maleic anhydride copolymer and the like.

[0037] The above water-absorbent resin precursor is, for example, (meth) acrylic acid, maleic acid, maleic anhydride, fumaric acid, crotonic acid, itaconic acid, beta-acryloyloxy such acid unsaturated carboxylic acids or after one or more monomers selected from the neutralized product of polymerized or copolymerized, performs operations such as pulverization and classification as required with respect to the polymer, by adjusting the average particle size of the can get. Among the above monomers, (meth) acrylic acid and neutralized products thereof are more preferred.

[0038] Further, the water-absorbing resin precursor, and the monomer, or a copolymer of said monomer copolymerizable with another monomer. As the another monomer, specifically,
For example, vinyl sulfonic acid, styrene sulfonic acid, 2-
(Meth) acrylamido-2-methylpropanesulfonic acid, 2- (meth) acryloyl ethanesulfonic acid, 2-
(Meth) acrylate anionic unsaturated monomers and salts thereof such as acryloyl propane sulfonic acid; acrylamide, methacrylamide, N- (meth) acrylamide, N
-n- propyl (meth) acrylamide, N- isopropyl (meth) acrylamide, N, N- dimethyl (meth) acrylamide, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, methoxy polyethylene glycol (meth ) acrylate, polyethylene glycol mono (meth) acrylate, vinyl pyridine, N- vinylpyrrolidone, N- acryloylpiperidine, N- acrylic cationic unsaturated monomers such as acryloyl pyrrolidine; N, N- dimethylaminoethyl ( meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylamide, and these quaternary salts And cationic unsaturated monomers such.

The content of the carboxyl group in the water-absorbent resin precursor is not particularly limited, per 100g water-absorbing resin precursor, preferably to be present from 0.01 or more equivalents of carboxyl groups. Further, when the water-absorbing resin precursor is, for example, partially neutralized polyacrylic acid crosslinked body, the proportion of polyacrylic acid unneutralized product in crosslinked body is in the range of 1 mol% to 60 mol% preferably, 10 mole%
In the range of 50 mol% it is more preferable.

The water-absorbing resin precursor, and a plurality of polymerizable unsaturated groups, by reacting or copolymerizing the cross-linking agent having a plurality of reactive groups, it is preferable that the inside is crosslinked. Further, the water-absorbing resin precursor may be self-crosslinking which does not require cross-linking agent. Examples of the crosslinking agent, specifically, for example, N, N'-methylenebis (meth) acrylamide, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, trimethylolpropane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, glycerin tri (meth) acrylate, glycerin acrylate methacrylate, ethylene oxide-modified trimethylolpropane tri (meth)
Acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, triallyl cyanurate, triallyl isocyanurate, triallyl phosphate, triallylamine, poly (meth) allyloxy alkane, (poly) ethylene glycol di glycidyl ether, glycerol diglycidyl ether, ethylene glycol, polyethylene glycol, propylene glycol, glycerol, pentaerythritol, ethylenediamine, polyethyleneimine, and glycidyl (meth) acrylate. These crosslinking agents may be used alone or may be used as a mixture of two or more. Among the listed compounds, it is more preferable to use a compound having a plurality of polymerizable unsaturated groups as the crosslinking agent.

The amount of the crosslinking agent is preferably in a range of 0.005 mol% to 2 mol% based on the total amount of the monomers, 0.
05 in the range of mole% to 1 mole% being more preferred. When the amount of the crosslinking agent is less than 0.005 mol%, and, when more than 2 mol%, the diffusion absorbency of the water absorbent resin is undesirably reduced.

Further, at the time of polymerization initiation of the polymerization reaction, for example, potassium persulfate, ammonium persulfate, sodium persulfate, t- butyl hydroperoxide,
Hydrogen peroxide, 2,2'-azobis (2-amidinopropane) radical polymerization initiator such as dihydrochloride, or can be used an active energy ray such as ultraviolet ray or electron beam. In the case of using an oxidizing radical polymerization initiator, for example, sodium sulfite, sodium bisulfite, may be performed redox polymerization in combination ferrous sulfate, a reducing agent such as L- ascorbic acid. The amount of the polymerization initiator is preferably in the range of 0.001 mol% to 2 mol%, and more preferably in the range of 0.01 mol% to 0.5 mol%.

[0043] The above water-absorbent resin precursor, the diffusing absorbency does not satisfy the preferable range of the present invention.
Thus, by using a specific surface cross-linking agent must be higher than the internal cross-linking density in the vicinity of the surface of the water absorbent resin precursor. In other words, by cross-linking the neighborhood of the surface of the water-absorbent resin precursor using the specific surface-crosslinking agent, a water-absorbent resin according to the present invention is obtained.

[0044] That is, the water-absorbent resin according to the present invention, the water-absorbing resin precursor obtained by aqueous solution polymerization mentioned above, i.e., an average particle size in the range of 200Myuemu～600 [mu] m, moreover, the particle size is less than 106μm after adjusting the operation such as classification as the proportion of particles is 10 wt% or less, by heating in the presence of a water-absorbent resin precursor solubility parameter ranges from each other two or more different surface cross-linking agent can get. The water absorbent resin, i.e., the water-absorbing resin precursor may be granulated into a predetermined shape, spherical, scale-like, irregular pulverized shape, but may have a variety of shapes of granular shape. Furthermore, the water-absorbing resin precursor may be a primary particle, or may be a granule of the primary particles. still,
And when the average particle diameter is outside the range of 200μm~600 μm,
When the particle size ratio of particles less than 106μm exceeds 10 wt%, it may not be possible to obtain an excellent water-absorbent resin performance such as diffusion absorption capacity.

[0045] The surface crosslinking agent is formed by combining a solubility parameter (SP value) is different the first surface crosslinking agent and a second surface crosslinking agent. Note that the above-mentioned solubility parameter is a value which is generally used as a factor representing the polarity of the compound. In the present invention, with respect to the solubility parameter, Polymer Handbook 3rd edition (WI
LEY INTERSCIENCE published by) the solvents described in page 527 to 539 pages solubility parameter δ (cal / cm ³⁾ and applying a ^half value. With respect to the solubility parameter of the solvent is not described in pages described above, expression of Small listed in 524 pages of the Polymer Handbook, the 5
And applying a value derived by substituting a cohesive energy constant of Hoy listed in page 25.

The first surface cross-linking agents described above, capable of reacting with a carboxyl group, a solubility parameter of 12.5 (cal / cm ^{3) 1/2} or more compounds are ^{preferable, 13.0 (cal / cm 3)} 1/2 or more compounds are more preferable. The first surface cross-linking agents described above, such as ethylene glycol, propylene glycol, glycerol, pentaerythritol, sorbitol, ethylene carbonate (1,3-dioxolan-2-one),
Propylene carbonate (4-methyl-1,3-dioxolan-2-one), and the like, but not limited to these compounds. These first surface-crosslinking agents may be used alone or may be used as a mixture of two or more.

The second surface cross-linking agents described above, capable of reacting with a carboxyl group, a solubility parameter of preferably 12.5 (cal / cm ³⁾ a compound of less than ^{1/2, 9.5 (cal / cm 3} ) 1/2 ~12.0 (cal / c
m ³⁾ compound in ^1/2 of the range is more preferable. The above as the second surface crosslinking agent, for example, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol,
1,3-butanediol, 1,4-butanediol,
1,5-pentanediol, 2,4-pentanediol, 1,6-hexanediol, 2,5-hexanediol, trimethylolpropane, diethanolamine,
Triethanolamine, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerol polyglycidyl ether, diglycerol polyglycidyl ether, polyglycerol polyglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, ethylenediamine, diethylenetriamine, triethylenetetramine tetraethylenepentamine, 2,4-tolylene diisocyanate, hexamethylene diisocyanate, 4,5-dimethyl-1,3-dioxolan-2-one, epichlorohydrin, although epibromohydrin and the like, limited to compounds not intended to be. These second surface-crosslinking agents may be used alone or may be used as a mixture of two or more.

[0048] In the present invention, as the surface cross-linking agent, one kind or two or more compounds selected from the group of the first surface crosslinking agent, and, one or two selected from the group of the second surface crosslinking agent it is necessary to use together or more compounds. When using only one or two or more of the first surface-crosslinking agent, or one or a case of using only two or more kinds of the second surface-crosslinking agent has excellent water absorption performance such as diffusion absorption capacity it may not be possible to obtain a resin.

The amount of the surface cross-linking agent varies depending on the compounds and combinations thereof, and the like to be used, 100 parts by weight of the solid content of the water-absorbent resin precursor, the amount of the first surface crosslinking agent is 0.
01 to 5 parts by weight, the amount of the second surface crosslinking agent is 0.001
Preferably in a range of parts by weight to 1 parts by weight, to 2 parts by weight 0.1 parts by weight The amount of the first surface crosslinking agent, the amount of the second surface-crosslinking agent is in a range of 0.005 parts by weight to 0.5 parts by weight and more preferable. By using the above surface cross-linking agent, the water-absorbing resin precursor, i.e., the crosslink density in the vicinity of the surface of the water-absorbent resin may be higher than the internal. The amount of the surface cross-linking agent
If exceeding 10 parts by weight, not only uneconomical, in order to form an optimal crosslinking structure in the water-absorbent resin, the amount of the surface crosslinking agent is excessive, undesirable. Further, when the amount of the surface cross-linking agent is less than 0.001 part by weight, to improve the performance such as diffusion absorption capacity water-absorbing resin, since the improving effect is hardly obtained, which is not preferable.

[0050] In mixing the water-absorbent resin precursor and the surface crosslinking agent, it is preferable to use water as a solvent. The amount of water depends on the type or particle diameters of the water-absorbent resin precursor, 100 parts by weight of the solid content of the water-absorbing resin precursor, 0
Traversal, preferably 20 parts by weight or less, and more preferably in the range of 0.5 to 10 parts by weight.

[0051] Furthermore, in mixing the water-absorbent resin precursor and the surface crosslinking agent, it may optionally be used a hydrophilic organic solvent as a solvent. Examples of the hydrophilic organic solvent,
For example, methyl alcohol, ethyl alcohol, n- propyl alcohol, isopropyl alcohol, n- butyl alcohol, isobutyl alcohol, lower alcohols such as t- butyl alcohol; ketones such as acetone;
Ethers such as dioxane and tetrahydrofuran; N,
N- amides such as dimethylformamide; sulfoxides such as dimethyl sulfoxide and the like. The amount of the hydrophilic organic solvent depends upon such as type or particle diameters of the water-absorbing resin precursor, 100 parts by weight of the solid content of the water-absorbent resin precursor is preferably 20 parts by weight or less, 0.1 parts by weight more preferably in the range of 10 parts by weight.

[0052] Then, in mixing the water-absorbent resin precursor and the surface crosslinking agent, for example, after dispersing the water-absorbent resin precursor into the above hydrophilic organic solvent, a mixture of surface crosslinking agent it may also be, but the mixing method is not particularly limited. Among various mixing methods, the surface crosslinking agent dissolved in water and / or a hydrophilic organic solvent, if necessary, directly to the water-absorbing resin precursor, a method of mixing spraying or dropping to is preferred. Further, in the case of mixing with water, and particulate powder insoluble in water, it may coexist surfactants.

[0053] mixing used in mixing the water-absorbent resin precursor and the surface-crosslinking agent system, to mix both uniformly and surely, it is preferable that has great mixing power. The mixing device described above, for example, a cylindrical type mixer,
Double-wall cone type mixers, V-shaped mixer, a ribbon type mixer,
Screw type mixers, fluidized-furnace rotary disk type mixers, gas current type mixers, twin-arm kneaders, internal mixers, pulverizing type kneaders, rotary mixers, and screw type extruders.

[0054] After mixing the water-absorbent resin precursor and the surface-crosslinking agent, heat treatment is performed to cross-link the neighborhood of the surface of the water-absorbing resin precursor. Treatment temperature of the heat treatment depends on the surface cross-linking agent used, 160 ° C. or higher, preferably 250 ° C. or less.
Because if the processing temperature is lower than 160 ° C. is not uniform crosslinking structure is formed, therefore, it is not possible to obtain an excellent water-absorbent resin performance such as diffusion absorption capacity unfavorably. If the processing temperature exceeds 250 ° C. causes deterioration of the water-absorbing resin precursor, because the performance of the water absorbent resin decreases, which is not preferable.

[0055] The above heat treatment can be carried out using conventional dryers or heating furnaces. As the dryer, for example, channel type mixing dryers, rotary dryers, desk dryers, fluidized-bed dryers, gas stream type dryers, and infrared dryers.

[0056] obtained by the above manufacturing method water-absorbent resin, diffusing absorbency of 30 minutes after the absorption initiation is at 15 g / g or more, and a diffusion absorbency after 60 minutes 25 g / g or more is there. Further, the absorber of the present invention is adapted include the water-absorbent resin 40 wt% or more. Therefore, the absorber has an excellent water absorption properties as described above. Thus, the absorbent body, for example, held in the case of using the absorbent article, and when the amount of the water absorbent resin is large, when the resin concentration in the absorbent high, very high liquid-diffusivity and the water absorption excellent can exhibit performance (absorption properties) such as to.

[0057] Absorber with water-absorbent resin in the present invention cause is not clear that a very good diffusing absorbency such performance, but the liquid diffusion and liquid transfer of the aqueous liquid in the absorber during in the conventional absorbent, while being undertaken by capillary action of the hydrophilic fibers in the absorbent body of the present invention have excellent diffusing absorbency obtained by performing particular surface crosslinking process water presumably because the high liquid-diffusivity provided sexual resin (liquid distribution capacity and liquid transfer capacity) is sufficiently exhibited even in the absorbent body.

[0058] In addition, the absorbent article according to the present invention, the absorbing layer comprising an absorber configured as described above, formed by sandwiched a sheet having liquid permeability, a sheet having a liquid-impervious. Then, the absorbent article, since it has an absorption layer comprising an absorber configured as described above, has excellent water absorption properties as described above. Absorbent articles, particularly, for example, paper diapers and sanitary napkins, but sanitary materials called incontinent pads and the like, but is not particularly limited.
Because the absorbent article has excellent water absorption properties, for example, when the absorbent article is a paper diaper, it is possible to prevent leakage of urine, it is possible to impart a so-called dry feeling.

[0059] sheet having a liquid-pervious above (hereinafter, referred to as liquid-permeable sheet) is made of a material having a property of transmitting an aqueous liquid. As the material of the liquid-permeable sheet, for example, a nonwoven fabric, woven fabric, polyethylene, polypropylene, polyester, synthetic resin porous film composed of a polyamide or the like, and the like. Sheet having the above-mentioned liquid-impermeable (hereinafter, referred to as liquid-impermeable sheet) is made of a material having a property of not transmitting an aqueous liquid. As the material of the liquid-impermeable sheet, for example, polyethylene, polypropylene, ethylene vinyl acetate, synthetic resin films made of polyvinyl chloride or the like; a composite material of these synthetic resins with nonwoven film; the synthetic resin and the fabric and the like of a composite material film.
The liquid impermeable sheet may have a property of transmitting steam.

[0060] The absorbent layer structure is not limited in particular, it needs to have an absorber above. The manufacturing method of absorbent layers is not particularly limited. further,
How to sandwich the absorbent layer between the liquid-permeable sheet and the liquid-impermeable sheet, namely, the method of manufacturing the absorbent article 1 is not particularly limited.

[0061] In addition, further deodorant to the absorption of the above-mentioned, perfume,
Various inorganic powders, foaming agents, pigments, dyes, hydrophilic short fibers,
Fertilizers, oxidizing agents, reducing agents, water was added salts and the like, thereby, may be granted various functions to the absorbent body or absorbent article.

[0062]

[Action] As described above, the water-absorbing resin having the above structure can exhibit excellent performance such as to retain the very high liquid-diffusivity and water absorption amount (water absorption properties). Further, the absorber having the above-shown and when the amount of the water absorbent resin is large, when the resin concentration in the absorbent high, excellent performance, such as to retain a very high liquid-diffusivity and the water absorption be able to. The above absorbent body, for example, higher performance and thinning desired is to have disposable diapers, sanitary napkins, can be particularly preferably used in an absorbent article of hygiene materials called incontinent pads and the like. Thus, it is possible to provide an absorbent article showing the above-mentioned excellent performance.

[0063]

EXAMPLES The following examples and comparative examples, the present invention will be described in further detail, the present invention should not be construed as being limited thereto. Incidentally, various properties of the water absorbent resin and absorbent bodies were measured by the following method.

[0064] The (b) water absorption capacity absorbent resin 0.2g uniformly put into a bag made of nonwoven fabric (60 mm × 60 mm), was immersed in 0.9 wt% aqueous sodium chloride solution (saline). The bag was pulled up after 60 minutes, after 3 minutes drained 250G using a centrifugal separator, the weight W of the bag
₁ (g) was measured. Also conducted without using the water absorbent resin the same procedure and weighed W ₀ (g) at that time. From these weight W ₁ · W _0, the following equation, the absorption capacity (g / g) = (Weight W ₁ (g) - weight W ₀ (g)) / weight of absorbent resin (g) in accordance with the water absorption ratio ( g / g) was calculated.

[0065] (c) diffusing absorbency of the absorbent body First, the measurement device used for measuring the diffusing absorbency of the absorbent body, with reference to FIGS. 4 and 5 will be briefly described below. For convenience of explanation, wherein the arrangement has a measuring device and the same functions used in the measurement of diffusion absorption capacity, the same reference numerals, and description thereof is omitted.

[0066] As shown in FIG. 4, the measuring device, the balance 1
When a container 2, an air-inhaling pipe 3, a conduit 4, a diameter of 1
A glass filter 6 is formed in 20 mm, which is from the measurement unit 15 which is placed on the glass filter 6. As shown in FIG. 5, the above-mentioned measurement unit 15, the filter paper 7, a seat 8, a supporting rectangular tube 19, and a weight 11.
Incidentally, the wire mesh does not.

[0067] Measurement unit 15, on the glass filter 6, the filter paper 7, the sheet 8, with the support rectangular tube 19 is placed in this order, supporting rectangular tube 19 inside the weight 11 is made is placed. Sheet 8 is made of polyethylene terephthalate, and is formed in a rectangular shape having a thickness of 0.1mm having a rectangular opening of 12.5 mm × 100 mm in a central portion. Support angle cylinder 19
The inner dimensions are formed on 100 mm × 100 mm. The absorbent body having a predetermined size to the internal support angle cylinder 19 is adapted to be placed. Other configurations of the measuring device is the same as the measuring apparatus used for measuring the diffusing absorbency.

[0068] was measured diffusing absorbency of the absorbent body using a measurement device with the above structure. It will be described below measurement method.

[0069] First, to form an absorber to a size of 100 mm × 100 mm. In addition, it performs a predetermined preparation operation. Next, placing a filter paper 7 on the glass filter 6, the sheet 8 on the filter paper 7, the opening portion is placed so as to be positioned in the center of the glass filter 6. Then, the support angle cylinder 19 on the seat 8, the central portion is placed so as to coincide with the center of the glass filter 6.

[0070] Then, the internal supporting rectangular tube 19, i.e., placing the absorbent body on the sheet 8, placing the weight 11 on the absorber. It should be noted, 置動 work placement of the absorbent body and the weight 11 was carried out quickly.

[0071] Then, measured from the time of placing the absorbent body on the sheet 8, 30 minutes, or, the weight W ₃ of physiological saline 12 where the absorber has absorbed water over 60 minutes (g), using the balance 1 did. As shown in FIG. 6, saline 12
It passes through the opening of the seat 8, while almost uniformly diffused in the absorbent body in the transverse direction, which is absorbed by the absorbent body.

[0072] Then, the weight W ₃ of the following formula, according to the weight of the diffusing absorbency (g / g) = Weight W ₃ (g) / absorber of the absorber (g), 30 minutes after the water started, Alternatively, after 60 minutes, it was calculated diffusing absorbency of the absorbent body (g / g).

[0073] Example 1 to 30 wt% aqueous solution 5500g of sodium acrylate (neutralization ratio 65 mol%) as a monomer, polyethylene glycol diacrylate as a crosslinking agent (average addition mole number of ethylene oxide: 8) 18.49 and a reaction solution of g. Then, the reaction solution was deaerated for 30 minutes under a nitrogen gas atmosphere. Then, the reactor by lidding a jacketed stainless twin-arm kneader having an inner volume of 10L for 2 inborn sigma type blades, and supplying the reaction liquid, the reaction liquid 30
℃ in the system while keeping was replaced nitrogen gas. Subsequently, while stirring the reaction solution, ammonium persulfate 2.3g and L-
Was added ascorbic acid 0.12 g, polymerization was initiated about 1 minute later. The polymerization is proceeded at 30 ° C. to 80 ° C., was removed hydrogel polymer was 60 minutes after the initiation of polymerization.

[0074] obtained water-containing gel-like polymer particle has a diameter subdivided into approximately 5 mm. Spread The finely divided hydrous gel-like polymer on a 50-mesh metal net and dried with hot air for 90 minutes at 0.99 ° C.. The dried product was pulverized with a vibration mill and further classified by a 20-mesh wire gauze, an average particle diameter of 360 .mu.m, moreover, the proportion of the particle size is less than 106μm particles 5% by weight of irregularly pulverized It was obtained Jo of the water-absorbing resin precursor.

[0075] the water-absorbing resin precursor 100 parts by weight of the obtained,
Glycerol (SP value as the first surface crosslinking agent: [delta] = 16.5
^{(cal / cm 3) 1/2)} 1 part by weight of ethylene glycol diglycidyl ether as a second surface-crosslinking agent (SP value: [delta] =
10.2 ^{(cal / cm 3) 1/2)} 0.05 parts by weight, and 3 parts by weight of water, was mixed with a surface crosslinking agent consisting of ethyl alcohol 1 part by weight. By heating for 40 minutes the mixture at 195 ° C., to obtain a water-absorbent resin. The average particle diameter of the resulting water-absorbent resin is 360 .mu.m, a particle size ratio of particles less than 106μm was 5 wt%. Absorption capacity and diffusing absorbency of the water absorbing resin (hereinafter, simply results referred) were shown together in Table 1.

[0076] in EXAMPLE 2 39 wt% aqueous solution 5500g of sodium acrylate (neutralization ratio 75 mol%), and a reaction solution of trimethylolpropane triacrylate 3.59g as a crosslinking agent. Then, the reaction solution was deaerated for 30 minutes under a nitrogen gas atmosphere.
Then, the reactor similar to the reactor of Example 1, and supplying the reaction mixture, the system was substituted nitrogen gas while maintaining the reaction solution at 30 ° C.. Subsequently, while stirring the reaction solution, it was added ammonium persulfate 2.4g and L- ascorbic acid 0.12 g, polymerization was initiated about 1 minute later. Then, 30 ℃
Polymerization was conducted at to 80 ° C., was removed hydrogel polymer was 60 minutes after the initiation of polymerization.

[0077] obtained water-containing gel-like polymer particle has a diameter subdivided into approximately 5 mm. Spread The finely divided hydrous gel-like polymer on a 50-mesh metal net and dried with hot air for 90 minutes at 0.99 ° C.. The dried product was pulverized with a vibration mill and further classified by a 20-mesh wire gauze, an average particle diameter of 400 [mu] m, moreover, the proportion of the particle size is less than 106μm particles 5% by weight of irregularly pulverized It was obtained Jo of the water-absorbing resin precursor.

[0078] the water-absorbing resin precursor 100 parts by weight of the obtained,
Ethylene glycol (SP value as the first surface crosslinking agent:
^{δ = 14.6 (cal / cm 3} ) 1/2) and 0.5 part by weight of glycerol polyglycidyl ether as a second surface-crosslinking agent (SP
Value: δ = 10.8 (cal / cm 3) 1/2) and 0.1 part by weight, and 3 parts by weight of water, was mixed with a surface crosslinking agent consisting of ethyl alcohol 1 part by weight. By heating for 40 minutes the mixture at 195 ° C., to obtain a water-absorbent resin. The average particle diameter of the resulting water-absorbent resin was 400 [mu] m, particle diameter ratio of particles less than 106μm was 3 wt%. The results of this water absorbent resin described in accordance with the Table 1.

[0079] 20 wt% aqueous solution 5500g of Example 3 sodium acrylate, N as a crosslinking agent, N'- methylenebisacrylamide 2.35
And a reaction solution of g. Then, the reaction solution was deaerated for 30 minutes under a nitrogen gas atmosphere. Then, the reactor similar to the reactor of Example 1, and supplying the reaction liquid, the reaction solution
The system while maintaining the temperature at 30 ℃ was replaced nitrogen gas. Subsequently, while stirring the reaction solution, ammonium persulfate 1.5g and L
- it was added ascorbic acid 0.07 g, polymerization was initiated about 1 minute later. Then, a polymerization at 30 ℃ ~80 ℃,
After 60 minutes the start of the polymerization, sodium carbonate neutralizing agent
After further stirring added 606.7G, it was removed hydrogel polymer.

[0080] The resulting hydrogel polymer is a neutralization ratio of 75 mol%, its diameter has been subdivided into approximately 5 mm. Spread The finely divided hydrous gel-like polymer on a 50-mesh metal net and dried with hot air for 90 minutes at 0.99 ° C.. The dried product was pulverized with a vibration mill and further classified by a 20-mesh wire gauze, an average particle diameter of 390 [mu] m, moreover, irregular pulverized fraction of particle size less than 106μm particle 4 wt% It was obtained Jo of the water-absorbing resin precursor.

[0081] the water-absorbing resin precursor 100 parts by weight of the obtained,
Propylene glycol as the first surface crosslinking agent (SP
Value: δ = 12.6 (cal / cm 3) 1/2) 0.75 parts by weight, propylene glycol diglycidyl ether as a second surface-crosslinking agent (SP value: δ = 10.1 (cal / cm 3) 1/2) 0.05 and parts by weight and 3 parts by weight of water, was mixed with a surface crosslinking agent consisting of ethyl alcohol 0.75 parts by weight. By heating for 40 minutes the mixture at 195 ° C., to obtain a water-absorbent resin. The average particle diameter of the resulting water-absorbent resin was 390 [mu] m, the particle diameter is 106μm
Percentage of particles less than was 3 wt%. The results of this water absorbent resin described in accordance with the Table 1.

[0082] In Comparative Example 1 39 wt% aqueous solution 5500g of sodium acrylate (neutralization ratio 75 mol%), and a reaction solution of trimethylolpropane triacrylate 7.18g as a crosslinking agent. Then, the reaction solution was deaerated for 30 minutes under a nitrogen gas atmosphere.
Then, the reactor similar to the reactor of Example 1, and supplying the reaction mixture, the system was substituted nitrogen gas while maintaining the reaction solution at 30 ° C.. Subsequently, while stirring the reaction solution, it was added sodium persulfate 5.0g and L- ascorbic acid 0.25 g, polymerization was initiated about 1 minute later. Then, 30 ℃ ~
Polymerization was conducted at 80 ° C., was removed hydrogel polymer was 60 minutes after the initiation of polymerization.

[0083] obtained water-containing gel-like polymer particle has a diameter subdivided into approximately 5 mm. Spread The finely divided hydrous gel-like polymer on a 50-mesh metal net and dried with hot air for 90 minutes at 0.99 ° C.. The dried product was pulverized with a vibration mill and further classified by a 20-mesh wire gauze, an average particle diameter of 360 .mu.m, moreover, the proportion of the particle size is less than 106μm particles 5% by weight of irregularly pulverized It was obtained Jo comparative water absorbent resin. The results of the resultant comparative water-absorbent resin described in accordance with the Table 1.

[0084] Comparative Example 2 in place of trimethylol propane triacrylate in Comparative Example 1, N as a crosslinking agent, except for using N'- methylenebisacrylamide 18.67 g, similar to Comparative Example 1 Reaction and operation It was carried out, an average particle diameter of 400 [mu] m, moreover, particle size ratio of particles less than 106μm was obtained 3 wt% of the irregular pulverized shape comparative water-absorbing resin. The results of the resultant comparative water-absorbent resin described in accordance with the Table 1.

[0085] Comparative Example 3 partially neutralized and crosslinked acrylic acid polymers:; was (trade name AQUALIC CA · W4 manufactured by Nippon Shokubai Co., Ltd.) Comparative water-absorbent resin. The results obtained are shown together in Table 1.

[0086] Comparative Example 4 partially neutralized and cross-linked starch - acrylic acid graft polymer :; was comparative water-absorbing resin (trade name San wet IM3900P Hoechst Celanese Corporation). The results obtained are shown together in Table 1.

[0087] Comparative Example 5 partially neutralized and crosslinked acrylic acid polymers:; was (trade name Dia wet US2-45Z Mitsubishi Petrochemical Co., Ltd.) Comparative water-absorbent resin. The results obtained are shown together in Table 1.

[0088] Comparative Example 6 partially neutralized and crosslinked acrylic acid polymers:; was (trade name AQUA KEEP SA-60 manufactured by Sumitomo Seika Chemicals Co., Ltd.) Comparative water-absorbent resin. The results obtained are shown together in Table 1.

[0089] removed water absorbent resin from a paper diaper called Comparative Example 7 Corporation Unicharm manufactured Mamipoko (trade name), was compared for the water absorbent resin so. The results obtained are shown together in Table 1.

[0090]

[Table 1]

[0091] and [Example 4] Example 45 parts by weight resulting water-absorbing resin 1, and a crushed wood pulp 55 parts by weight of a hydrophilic fiber, were dry blended using a mixer. The resulting mixture was molded into a web of the size of 100 mm × 100 mm, the web pressure 2 kg / cm ²
In by pressing for 1 minute, a basis weight of about 0.050 g / cm ²
It was obtained of the absorber. Diffusing absorbency of the resulting absorbent (hereinafter, simply results referred) were shown together in Table 2.

[0092] and [Example 5] Example the water-absorbent resin 50 parts by weight obtained in 1, and 50 parts by weight of crushed wood pulp were dry-mixed using a mixer. The resulting mixture was molded into a web of the size of 100 mm × 100 mm, by pressing for 1 minute with this web under a pressure 2 kg / cm ^2, a basis weight to obtain an absorber of about 0.047 g / cm ^2. The results of the absorption body were shown together in Table 2.

[0093] and Example 6 Example 60 parts by weight of the resulting water-absorbent resin 1, and 40 parts by weight of crushed wood pulp were dry-mixed using a mixer. The resulting mixture was molded into a web of the size of 100 mm × 100 mm, by pressing for 1 minute with this web under a pressure 2 kg / cm ^2, a basis weight to obtain an absorber of about 0.041 g / cm ^2. The results of the absorption body were shown together in Table 2.

[0094] and Example 7 Example the water-absorbent resin 75 parts by weight obtained in 1, and 25 parts by weight of crushed wood pulp were dry-mixed using a mixer. The resulting mixture was molded into a web of the size of 100 mm × 100 mm, by pressing for 1 minute with this web under a pressure 2 kg / cm ^2, a basis weight to obtain an absorber of about 0.035 g / cm ^2. The results of the absorption body were shown together in Table 2.

[0095] In Example 8, 9] Example 7, in place of the water-absorbent resin obtained in Example 1, the water-absorbing resin obtained in Example 2, Example 3 except for using sequentially respectively to obtain an absorbent layer in example 7. The results of the absorption body were shown together in Table 2.

[0096] In Comparative Example 8] In Example 4, instead of the water-absorbent resin obtained in Example 1, except for using the comparative water-absorbent resin obtained in Comparative Example 1, as in Example 4 It was obtained for comparison absorber. The results of the comparative absorbent body obtained as described in accordance with the Table 2.

[0097] In Comparative Example 9 Example 5, instead of the water-absorbent resin obtained in Example 1, except for using the comparative water-absorbent resin obtained in Comparative Example 1, similarly to Example 5 It was obtained for comparison absorber. The results of the comparative absorbent body obtained as described in accordance with the Table 2.

[0098] In Comparative Example 10] In Example 6, instead of the water-absorbent resin obtained in Example 1, except for using the comparative water-absorbent resin obtained in Comparative Example 1, similarly to Example 6 It was obtained for comparison absorber. The results of the comparative absorbent body obtained as described in accordance with the Table 2.

[0099] In Comparative Example 11 to 17] Example 7, in place of the water-absorbent resin obtained in Example 1, using the comparative water-absorbent resin obtained in Comparative Example 1 to Comparative Example 7 in order, respectively except, to obtain a comparative absorbent layer in example 7. Table 2 The results of the comparative absorbent body obtained
Described in accordance with the.

[0100]

[Table 2]

[0102] and Example 10 Example the water-absorbent resin 50 parts by weight obtained in 1, and 50 parts by weight of crushed wood pulp were dry-mixed using a mixer. Then, the resulting mixture, 400 mesh (mesh size: 38
By air papermaking using a batch-type air paper making device onto a wire screen formed to [mu] m), 120 mm ×
It was formed to 400mm of the size of the web. Furthermore, by 5 seconds pressing this web under a pressure 2 kg / cm ^2, a basis weight to obtain an absorber of about 0.047 g / cm ^2.

[0102] Subsequently, made from the liquid impermeable polypropylene, the back sheet having a so-called leg gather (liquid-impermeable sheet), the absorber above and the topsheet (liquid-permeable consisting liquid-permeable polypropylene sheets), the stuck together in this order by using a double-sided tape, by attaching the two so-called tape fasteners to the stuck kimono, give an absorbent article (i.e., paper diaper). The weight of this absorbent article was 46 g.

[0103] The absorbent article of the so-called Kewpie doll (body length 55cm, weight 5 kg) is attached to, after the a prone position the doll, the urination tube insertion, in the human body between the absorbent article and the dolls at a position corresponding to a position to do so, the saline 50ml per were sequentially injected at 20 minute intervals. Then, they injected saline at leaked no longer absorbed by the absorbent article, and ends the injection operation, to determine the amount of saline was injected by this time.

[0104] Then, after repeated 4 times the measurement of the above,
The average of the resulting measured values ​​was determined and this value and absorption.
As a result, suction yield was 250 g.

[0105] In Comparative Example 18] In Example 10, in place of the water-absorbent resin obtained in Example 1, except for using the comparative water-absorbent resin obtained in Comparative Example 1, the same manner as in Example 10 It was obtained in comparative absorbent article. The weight of this comparative absorbent article was 46 g.

[0106] using the comparative absorbent article described above was repeated 4 times measured in the same manner as in Example 10, the average of the resulting measured values ​​was determined and this value and absorption. As a result, suction yield was 225 g.

[0107] Table in 1-Table 2 As apparent from the results described in, the water-absorbing resin and absorbent in accordance with the present invention, the diffusion absorption capacity is high, moreover, has a very high liquid-diffusivity. In other words, the difference between the absorption properties of the water absorbent resin and absorbent, and absorption properties of the water absorbent resin and absorbent for comparison of the present invention, particularly, it has become larger as resin concentration increases in the absorber Understand. As is clear from the results described in Example 10 and Comparative Example 18,
The absorbent article of the present invention, than comparative absorbent article, it can be seen that a very high absorption superior performance (absorption properties) such as to hold the (water absorption).

[0108]

The above water-absorbent resin according to the present invention has excellent performance (absorption properties) such as to retain a very high liquid-diffusivity and the water absorption
It can be shown. The above-described absorber, and when the amount of the water absorbent resin is large, when the resin concentration in the absorbent high, to exhibit excellent performance such that holds a very high liquid-diffusivity and the water absorption there is an effect that it is. The above absorbent body, for example, higher performance and thinning desired is to have disposable diapers, sanitary napkins, can be particularly preferably used in an absorbent article of hygiene materials called incontinent pads and the like. Thus, an effect that it is possible to provide an absorbent article showing the above-mentioned excellent performance.

BRIEF DESCRIPTION OF THE DRAWINGS

It is a schematic sectional view of a measuring device used for measuring the diffusing absorbency, which is one of performance indicated by the water-absorbent resin in the present invention; FIG.

2 is a cross-sectional view of a main part of the measuring device.

[3] In the measuring apparatus, it is an explanatory diagram for explaining a diffusion direction of saline.

It is a schematic sectional view of a measuring device used for measuring the diffusing absorbency, which is one of performance indicated by the absorber in the present invention; FIG.

5 is a cross-sectional view of a main part of the measuring device of FIG.

In the measurement apparatus of FIG. 6 FIG. 4 is an explanatory diagram for explaining a diffusion direction of saline.

DESCRIPTION OF SYMBOLS

1 balance 2 container 3 air-inhaling pipe 4 conduit 5 measuring unit 6 glass filter 7 filter paper 8 sheets 9 supporting cylinder 10 wire mesh 11 weight 12 saline 15 measuring unit 19 support rectangular tube

────────────────────────────────────────────────── ─── of the front page continued (72) inventor Shinichi Fujino Himeji, Hyogo Prefecture Aboshikuokinohama character Nishioki 1 Nippon Shokubai Co., Ltd. polymer within the Institute of address 992 (72) inventor Masuda, Yoshihiko Himeji, Hyogo Prefecture Aboshikuokinohama shaped Nishioki 992 address 1 Nippon Shokubai polymer in laboratory (56) references Patent Rights 2-132103 (JP, a) Patent Rights 6-184320 (JP, a) Patent Rights 7-88171 (JP, a) JP open flat 8-57310 (JP, a) (58 ) investigated the field (Int.Cl. ^6, DB name) B01J 20/26 C08F 8/00

Claims (7)

(57) [the claims]
1. 1. A diffusing absorbency after 60 minutes from the absorption initiation is 25 g
   / Absorber g or more at which the water-absorbent resin, characterized in that it comprises 40 wt% or more.
2. 2. The absorbent body according to claim 1, wherein diffusing absorbency of 30 minutes after the absorption initiation of the water absorbent resin is characterized in that it is 15 g / g or more.
3. 3. A comprises hydrophilic fibers, absorbent body according to claim 1 or 2 wherein the amount of the water-absorbing resin is equal to or less than 50% by weight relative to the total amount of the water-absorbent resin and hydrophilic fibers .
4. The 4. absorbing layer comprising an absorber according to any one of the claims 1 to 3, the sheet having a liquid-permeable, that is formed by sandwiched between the sheet having a liquid-impervious absorbent article characterized.
5. 5. The diffusing absorbency of 30 minutes after the absorption start 15 g
   / G or more, and water-absorbent resin diffusing absorbency after 60 minutes is equal to or is 25 g / g or more.
6. 6. A diffusing absorbency after 20 minutes from the absorption initiation is 15 g
   / G or more, and, the water-absorbent resin, wherein the diffusing absorbency after 60 minutes is 30 g / g or more.
7. In 7. the range of average particle size of 200 m to 600 .mu.m, the proportion of the particle size is less than 106μm particles 5 wt% or less
   Of the water-absorbent resin precursor having a carboxyl group, capable of reacting with the carboxyl group, the solubility parameter is 12.5 (c
   al / cm ^{3) 1/2} or more first surface crosslinking agent, and, by a solubility parameter of the heat treatment in the presence of 12.5 (cal / cm ^{3) 1/2} than the second surface-crosslinking agent, initiator absorbing expansion from after 60 minutes
   Method for producing a water-absorbing resin dispersed absorption capacity is characterized in that to obtain a water-absorbent resin is 25 g / g or more.