JPS582828B2 - Water-absorbing/water-retaining laminated material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a laminated material that has both water absorption and water retention properties, and more specifically, it is useful as paper diapers, sanitary products, sweat absorbent sheets for beds, cleaning wipes, paper rags, etc. The purpose is to provide a new water-absorbing and water-retaining laminated material.

Conventionally, paper diapers and sanitary products are made of highly absorbent paper, absorbent cotton, cotton pulp, etc., either alone or in combination.
Alternatively, it is manufactured using non-woven fabric, waterproof paper, etc., but in any case, the water absorption rate of the absorbent material is low, so there is a limit to the amount of water absorbed, and it is also possible to sufficiently prevent backflow phenomena and leakage to the outside. I can't.

In order to solve these drawbacks, it has been proposed to use a powder of a highly water-absorbing molecular material made by partially cross-linking a water-soluble polymer material by scattering it on the water-absorbing material described above. Although the water absorption rate is improved in some cases, the physical strength of the swollen gel produced when the water-absorbing polymer material absorbs water is low, and it easily deforms or collapses when pressure or other forces are applied, resulting in the problem of backflow still occurring. Unresolved issues or leakage issues.

Furthermore, since such materials are used in powder form in most cases, they also have the disadvantage of becoming lopsided or falling off due to movements of the wearer.

As a result of intensive research to solve the drawbacks of the prior art as described above, the present inventor has developed a water-absorbing/water-retaining laminated material that solves the various drawbacks described above by using specific materials in a specific manner. The present invention was completed based on the finding that the following could be obtained.

That is, the present invention provides a water-absorbing/water-retaining laminated material comprising a layer having water-absorbing and water-retaining properties and a water-insoluble and water-permeable diffusion layer, in which the layer having water-absorbing and water-retaining properties is substantially comprising a hydrophobic natural or synthetic rubber material and a water-swellable polymeric material, characterized in that the water-swellable polymeric material particles are dispersed in a continuous phase consisting of the natural or synthetic rubber material. It is a water-absorbing and water-retaining laminated material.

To explain the present invention in more detail, the laminated material of the present invention includes:
Basically, it consists of two layers: a layer that has water absorption and water retention properties (hereinafter simply referred to as the water absorption/water retention layer) and a water diffusion layer (hereinafter simply referred to as the diffusion layer) made of a water-insoluble but water-permeable material. Other embodiments include those having diffusion layers on both sides, and those having a waterproof layer on the opposite side of the diffusion layer.

In the laminated material of the present invention, the diffusion layer may be a conventional feminine hygiene product, a paper diaper, a sweat-absorbing bed sheet for sick patients,
The same absorbent materials used for cleaning wipes, paper rags, surgical blood absorbing materials, etc. may be used, such as paper,
This layer is made of absorbent cotton, cotton-like pulp, etc., and is constructed so that when it comes into contact with urine, blood, or other aqueous liquids, it immediately absorbs these liquids and diffuses the absorbed liquids.

It may have any shape as long as it has such a function, but it is most commonly paper-like, web-like, or gauze-like.

The above-mentioned cellulose fibers are typical, but nonwoven fabrics made from random webs of natural, recycled, and synthetic fibers such as cotton, rayon, acetate, nylon, polyester, and polyacrylonitrile may also be used.

The thickness of the above diffusion layer is preferably about 0.05 to 5 mm.

The water-absorbing/water-retaining layer in the present invention mainly characterizes the present invention, and is composed of a substantially hydrophobic natural or synthetic rubber material and a water-swellable polymer material as essential components.
The latter material is substantially uniformly dispersed within the former material.

The water-swellable polymer material that forms such a water-absorbing/water-retaining layer is a hydrophilic polymer material that absorbs water and swells significantly but is not substantially soluble in water, such as a chemically cross-linked hydrophilic polymer material. Examples include hydrophilic polymeric materials that have a similar effect to crosslinking with polymeric materials and physically restrained phases.

As such a hydrophilic polymer material, a conventionally known polymer material having a hydrophilic group can be used.

The hydrophilic groups of such polymer materials include carboxyl groups, sulfonic acid groups, sulfuric ester groups, phosphoric ester groups, polyethylene oxide sulfate groups, polyethylene phosphate groups, or These include alkali metal salts, ammonium salts, lower amine salts, alkanolamine salts, and alkali metal salts such as sulfonic acid groups.Cationic hydrophilic groups include primary, secondary, tertiary amine groups, and quaternary amine groups. Examples of the nonionic hydrophilic group include an alcoholic hydroxyl group, an ether group, an acid amide group, and a pyrrolidone group.

Among these, the most preferred are water-soluble salt groups of carboxyl groups and sulfonic acid groups.

Examples of hydrophilic polymer materials having hydrophilic groups as described above include the following.

(1) Acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, etc.: Monoalkyl (C1-C8) of dicarboxylic acids such as itaconic acid, maleic acid, fumaric acid, etc.
Esters, monoalkoxy (Ct~C4), alkyl (02~C3) esters, monocarbonamide, etc.: vinylsulfonic acid, styrenesulfonic acid, acryloyloxyethylsulfonic acid, etc.; N-N-dialkyl (C2~
C3) Aminoethyl acrylate, N/N-dialkyl (C2-C3) aminoethyl methacrylate, vinylpyridine, 2-hydroxy-3-methacryloxypropyltrimethylammonium chlorite, etc.: β-hydroxyethyl acrylate, β-hydroxyethyl Methacrylate, acrylamide, vinyl pyrrolidone, polyethylene glycol monoacrylate, polyethylene glycol monomethacrylate, etc.: Homopolymers, copolymers with each other, copolymers with other monomers that do not impart hydrophilicity, and ionic groups. In such cases, salts thereof as mentioned above.

(2) Hydrolysis products of homopolymers and copolymers of maleic anhydride, acrylonitrile, methacrylic nitrile, methyl acrylate, ethyl acrylate, etc., and salts thereof.

(3) hydroxyalkyl (C2-C3) acrylate, hydroxyalkyl (02-C3) methacrylate,
Homopolymers and copolymers of polyalkylene (C2-C3) glycol monoacrylate, polyalkylene (C2-C3) glycol monomethacrylate, sulfuric acid esters, phosphoric acid esters, reaction products with monochloroacetic acid, maleic anhydride, Reactants with acid anhydrides such as succinic anhydride and trimellitic anhydride, and their salts.

(4) Reaction products of homopolymers and copolymers having unsaturated ethylene groups, such as polybutadiene, polyisoprene, and polychloroprene, with thioglycolic acid, β-mercaptopropionic acid, etc., and reaction products with acetylsulfonic acid, etc. products, reaction products with maleic anhydride, etc., (1) to (4) above.
) and their salts.

(5) Sulfuric acid esters, phosphoric acid esters, and polymers of reaction products of homopolymers and copolymers having unsaturated ethylene groups such as polyptadiene and polyisoprene with thioglycol and 1-mercapto-2-propanol. Ethylene group epoxidized acidic sodium sulfite, diethylamine,
Reaction products with morpholine etc. and their salts.

(6) Polyesters using trimellitic acid, pyromellitic acid, sulfofucuric acid, etc., and their salts.

(7) Reaction products of unsaturated polyesters with thioglycolic acids using maleic acid, fumaric acid, itaconic acid, etc., and salts thereof.

Such hydrophilic polymer materials have the property of swelling in water by chemically crosslinking them, for example, as follows.
Manufactured by

(1) Approximately 0.0% during the polymerization reaction of the hydrophilic polymer material described above.
A method of copolymerizing or cocondensing by adding 0.5% to about 5% of a polyfunctional monomer, examples of such polyfunctional monomers include divinylbenzene, ethylene glycol diacrylate, triethylene glycol. Dimethacrylate, trimethylolpropane triacrylate, N-N-
These include methylene bisacrylamide, polyethylene glycol diglycidyl ether, and triisocyanate obtained by reacting trimethylolpropane with 3 moles of toluylene diisocyanate.

(2) Similarly, a method of copolymerizing by adding a polyfunctional polymer having an average molecular weight of at least 1000 or more and having a group capable of causing a copolymerization reaction during the polymerization reaction,
Examples of such polyfunctional polymers include di- or polyols obtained by reacting alkylene (02-C3) oxide with ethylene glycol, glycerin, trimethylolpropane, sorbitol, ethylenediamine, etc., polybutadiene having hydroxyl groups at both ends, or Esters of butadiene-styrene copolymers, etc. and α/β-ethylenically unsaturated carboxylic acids, or alkylene (C2-C3) glycol monoesters of these diols or polyols and α/β-ethylenically unsaturated carboxylic acids. Examples include those in which urethane is bonded via toluylene diisocyanate.

(3) Similarly, copolymerizing reactive monomers during the polymerization reaction,
After the reaction, crosslinks are formed either by self-crosslinking or by the action of crosslinking compounds, and these compounds include:
Examples include monomers such as N-methylol acrylamide and glycidyl methacrylate, hexamethoxymelamine, dimethylolglyoxal monourein, and a (1:3) reaction product of trimethylolpropane and toluylene diisocyanate.

As mentioned above, water-swellable polymeric materials in which hydrophilic polymeric materials are chemically crosslinked can be widely used, but the most preferable material is water-swellable polymeric materials in which hydrophilic polymeric materials are chemically crosslinked. It is a water-swellable polymeric material made of a block copolymer or a graft copolymer made of a hydrophilic polymer segment and a hydrophobic polymer segment forming a constrained phase.

In the above, the hydrophobic polymer forming the bound phase is a polymer portion that can form an insoluble bound phase without dissolving or finely dispersing even if it comes into contact with an aqueous medium, and has a conventionally known hydrophobic property, that is, lipophilic property. Although a wide variety of polymers can be used, it is particularly preferable to use a polymer that tends to form a crystalline phase or a highly aggregated phase.

For example, polystyrene, polyα-methylstyrene,
Polymers include polyethylene, polypropylene, polyacrylonitrile, polyurethane bonding, polyester containing aromatic rings, polyamide, and polyvinyl halide.

These hydrophobic polymers act as a constraining phase that inhibits the tendency of the hydrophilic segments to dissolve when they absorb water or are placed in water.

Therefore, it has the ability to absorb water at a fast rate, and even if it absorbs a large amount of water, it does not dissolve in the absorbed water or become sticky, forming a completely water-swollen body.

These block copolymers or graft copolymers include, in particular, copolymers having at least one (hydrophobically constrained segment)-(hydrophilic segment)-(hydrophobically constrained segment) bond type in their structure. is preferred.

The water-swellable copolymer described above is produced, for example, by the following method.

(1) For example, in a polystyrene-polyptadiene-polystyrene block copolymer, a copolymer with a reactive group (double bond in the case of polybutadiene) in the segment sandwiched between hydrophobic restraining segments has an anionic group and a cationic group. By subjecting a compound containing a group and/or a nonionic group or a compound containing a group that can be easily converted to a hydrophilic group such as an addition reaction, condensation reaction, or addition polymerization reaction, or further necessary modification reaction. A method of introducing hydrophilic groups by

(2) Synthesize a polymer or copolymer containing a hydrophilic group or a group that can be easily converted into a hydrophilic group as described above, block it with monomers and/or oligomers that can form hydrophobic constrained segments, and /
Alternatively, the copolymer used in the present invention can be obtained by graft polymerization or by further carrying out necessary modification reactions.

(3) Synthesize a polymer or copolymer containing a hydrophilic group as described above or a group that can be easily converted into such a hydrophilic group, and combine it with a polymer or copolymer that will become a hydrophobic restriction segment to form a block and/or graft. A method of obtaining a copolymer used in the present invention by converting it into a polymer or further performing necessary modification reactions.

etc.

The water-swellable copolymer described above consists of a combination of hydrophobic constrained segments and hydrophilic segments, as described above.
The average molecular weight of both segments is about 1000 or more, preferably about 3000 or more, and the composition ratio of both segments is 5-95% (by weight) of hard segment: hydrophilic segment: 95-5%, preferably 5-60%. %:95~40
%.

By changing this composition ratio, the degree of hydrophilicity of the resulting water-swellable copolymer can also be changed.

Furthermore, in the present invention, the water-swellable polymeric material as described above is used by being finely dispersed in a hydrophobic rubber material, but even if it is dispersed and mixed into such a hydrophobic rubber material, the present invention will not be affected. The water-swellable polymeric materials used for this purpose have a strong affinity for water, and it is surprising that the water-absorbing and water-retaining abilities of the water-swelling polymeric materials can be exerted by overcoming the cohesive force of such media. This is knowledge.

Preferred substantially hydrophobic natural or rubber materials for use in the present invention are natural rubber, polybutadiene,
Polyisoprene, butyl rubber, butadiene-styrene copolymer, butadiene-acrylic nitrile copolymer, polychloroprene, ethylene-propylene rubber, acrylic rubber, ethylene-vinyl acetate copolymer, polyvinyl butyral resin, silicone resin, urethane polymer Random copolymers, block copolymers, and graft copolymers are used as copolymers, among which telelock type, multi-type, and radial type block copolymers, which are generally called thermoplastic rubbers, are used. Polymers have excellent strength and are particularly preferred.

In addition, the above hydrophobic rubber material has flexibility, processability, texture,
Alternatively, in order to improve the rate of water swelling, it is also preferable to add hydrophobic liquid substances such as liquid paraffin, vaseline, liquid animal and vegetable oils, plasticizers, process oils, etc., and liquid polymers such as polyptene.

In addition to being blended alone, the hydrophobic rubber material as described above is preferably used in the form of being dissolved or dispersed in an organic solvent.

The water-swellable polymeric material used in the present invention is as described above.
Although it is hydrophilic, it is insoluble in water, and is often insoluble or sparingly soluble in organic solvents, and has the property of not melting.

Therefore, the water-swellable polymer material is not only finely and uniformly dispersed in the hydrophobic rubber material in the form of a fine powder, but also mixed with an organic solvent solution or dispersion of the rubber material using a conventionally known dispersing machine or mixer. , evenly and finely dispersed.

Preferred machines for dispersing these materials include a roll mill, a banharry mixer, a kneader, a ball mill, a sand mill, an attritor, and the like.

Further, at this time, various other additives can be optionally added depending on the purpose of use.

For example, necessary amounts of surfactants, fragrances, various dyes and pigments, activated carbon foaming agents, various pharmaceuticals, etc. are used in combination.

As described above, a composition for forming a water-absorbing/water-retaining layer is obtained, and the water-swellable polymer material accounts for about 10 to 90% by weight in the finally formed water-absorbing/water-retaining layer. Preferably, it is used in amounts.

Next, a method for manufacturing the water-absorbing/water-retaining laminated material of the present invention using the various materials described above will be explained as follows.

(1) Spread an organic solvent solution or dispersion of a hydrophobic rubber material in which the water-swellable polymeric material described above is finely and uniformly dispersed onto a water-absorbing material such as paper, cotton, or nonwoven fabric to form a diffusion layer. A method of coating or spraying using a normal method, then heating or leaving it at room temperature to volatilize the solvent and dry it to form a water absorbing/water retaining layer, and after coating or spraying, this coating Preferably, the material is immersed in a solvent or water in which the polymer composition is insoluble or poorly soluble to solidify and precipitate the water-swellable polymer composition, and the solvent is extracted and removed, followed by drying. A method of forming a water absorbing/water retaining layer having a thickness of approximately 0.1 to 2 mm.

(2) A melted product of a hydrophobic rubber material in which a water-swellable polymeric material is finely and uniformly dispersed is coated with paper, nonwoven fabric, etc. to an appropriate film thickness, preferably about 0.1 to 2 mm. A method of melting and coating a water-absorbing material to form a water-absorbing and water-retaining layer.

(3) By preparing a film-like material in advance from the solution, dispersion, or melt of the water-swellable polymeric material of (1) and (2) above, and attaching it to the water-absorbing material, Methods for forming water absorption/water retention layers, etc.

In the method described above, the water-swellable polymer composition is applied onto a glass plate, a polyester film, a thin stainless steel plate, a release paper, etc., and then a water-absorbing material forming a diffusion layer is placed on top of the water-swellable polymer composition. Methods such as drying and peeling afterwards are also effective.

In addition, if necessary, to further prevent liquid leakage,
For example, waterproof materials such as polyethylene, polypropylene, ethylene vinyl acetate, etc. can be applied, fused, or pasted to the surface of the water-absorbing/water-retaining layer on the opposite side of the diffusion layer.
It is also preferable to overlap them.

In this case, a water-swellable polymer composition that forms a water-absorbing/water-retaining layer is applied on top of the waterproof material, a water-absorbing material that forms a diffusion layer is placed on top of the waterproof material, and then the entire surface is coated by drying or other treatment. It is also possible to combine them into one.

In addition, conventionally known cotton, absorbent cotton, cotton-like pulp, nonwoven fabric, gauze, etc. may be used in combination in such applications.

As detailed above, the composition of the present invention can be used alone or in combination with other conventionally known materials to produce feminine hygiene products, paper diapers, sweat absorbing sheets, cleaning wipes, paper rags, and surgical blood absorbers. It is used for materials, etc., and has excellent properties such as quick absorption, excellent water retention, and ability to withstand force or load.

Furthermore, since it is shaped like a sheet, it does not curl, shift, or shift in shape as the wearer moves when worn.

Moreover, it does not become powdery and fall off.

Therefore, the thickness as a whole can be made extremely thin, and when worn, movement is not inhibited, and the garment can be worn with relatively little discomfort.

As mentioned above, since the object of the present invention has excellent properties, the packaging unit can be one package for one dose, or one package for several doses, or paper diapers, paper In the case of rags or surgical blood-absorbing materials, use paper rolls with perforations so that each dose can be cut out, or fold dozens or hundreds of sheets so that they are on top of each other and place them in a box with an opening at the top. A preferred method of use is to package the product so that it can be pulled out and used one after another.

In addition, it is preferable to use it not only in the form of a flat sheet, but also by rolling it or cutting it into a long, thin rod shape by joining both ends together, which is suitable for uses such as sanitary tampons. .

Next, reference examples (manufacturing examples of water-swellable polymeric materials) and examples will be given for specific explanation.

Note that parts and percentages in the text are based on weight.

Further, the degree of water swelling is calculated as follows.

Reference example 1 (Polystyrene H polybutadiene) - (Polystyrene)
A block copolymer mainly having a telechelic structure (polystyrene content 30%) was dissolved in cyclohexane, an equivalent amount of thioglycolic acid was added to the unsaturated double bonds of the polymer, and the mixture was further neutralized with an equivalent amount of sodium hydroxide. A water-swellable copolymer was obtained.

The water swelling degree of this product was about 180 times.

Reference Example 2 The block copolymer used in Reference Example 1 was dissolved in dioxane, its double bonds were reacted with acetylsulfonic acid made from concentrated sulfuric acid and acetic anhydride, and the mixture was neutralized with sodium hydroxide to produce a water-swellable copolymer. I got it.

The water swelling degree of this product was about 110 times.

Reference Example 3 Methyl methacrylate was graft-polymerized to the block copolymer having a polystyrene content of 30% used in Reference Example 1 using penzoyl peroxide as an initiator.

This was saponified with sodium hydroxide to obtain a water-swellable copolymer.

The water swelling degree of this product was about 40 times.

Reference Example 4 A block copolymer mainly having a telechelic structure of (polystyrene)-(methyl methacrylate-ethyl methacrylate (80:20) copolymer)-(polystyrene) (polystyrene content 40%) was enriched with sodium hydroxide, and water A swellable copolymer was obtained.

The water swelling degree of this product was about 60 times.

Reference Example 5 Obtained by co-condensing polystyrene terephthalate having hydroxyl groups at both ends and polyethylene maleate having carboxyl groups at both ends (polyethylene terephthalate valve ÷ polyethylene maleate) - (polyethylene terephthalate) (containing polyethylene maleate) A water-swellable copolymer was obtained by adding thioglycolic acid to the double bonds of a block copolymer mainly composed of telechelic type (70%) and neutralizing it with sodium hydroxide.

The water swelling degree of this product was about 70 times.

Reference Example 6 96 parts of sodium acrylate, 4 parts of polyethylene glycol (average molecular weight 4000)-bis(maleic acid monoester monosodium salt) and 0.2 parts of potassium persulfate
A water-in-oil emulsion was prepared by preparing an aqueous solution containing 5 parts of the copolymer in a petroleum-based hydrocarbon solvent, a polymerization reaction was carried out, and a water-soluble component was removed to obtain a water-swellable copolymer.

The degree of water swelling of this product was about 100 times.

Reference Example 7 In place of the monomer and crosslinking oligomer used in Reference Example 6, 85 parts of 2-hydroxy-3-methacryloxypropyltrimethylammonium chloride and (polyethylene oxide)-(polypropylene oxide H polyethylene oxide) were used. (However, the average molecular weight of polypropylene oxide is 3250, and the ratio of polyethylene oxide is about 80%.

), using 15 parts of dimethacrylic ester of Reference Example 6.
Polymerization reaction and purification were carried out in the same manner as above to obtain a water-swellable copolymer.

The degree of water swelling of this product was about 100 times.

Reference Example 8 In place of the monomer and crosslinking oligomer of Reference Example 6, 90 parts of monomethacrylate of polyethylene glycol (average molecular weight 450) and polyethylene glycol (
Polymerization reaction and purification were carried out in the same manner as in Reference Example 6 using 10 parts of bis(maleic acid monoester) having an average molecular weight of 10,000) to obtain a water-swellable copolymer.

The water swelling degree of this product was about 30 to 50 times.

Example 1 A linear polyurethane obtained by reacting hydroxyl-terminated polyethylene butylene adipate with a molecular weight of about 2000, 4,4'-diphenylmethane diisocyanate, and 1,4-butanediol in a molar ratio of 1:3:2 was dimethylated. It was dissolved in formamide to make a 20% solution.

The above formulation was mixed uniformly, glass beads were added, and the mixture was dispersed for 2 hours using a paint shaker (vibrating pigment disperser) to obtain a polyurethane solution in which the water-swellable copolymer was dispersed.

This was applied onto a diffusion layer made of two layers of highly absorbent paper used in feminine hygiene products.

This coated material was immersed in a 60% aqueous inglobil alcohol solution to coagulate and precipitate the resin on the paper, and at the same time, dimethylformamide was extracted.

Further, the remaining dimethylformamide was removed by immersing it in Inglovir alcohol.

Then, remove it from the solution, dry it, and cover it with a highly absorbent paper as a diffusion layer (
A polyurethane layer (approximately 0.15 mm thick) containing a finely dispersed water-swellable copolymer;
mm) is absorbed. The object of the present invention, which is used as a water-retaining layer, was obtained.

Prepare the water-absorbent/water-retentive laminated material obtained above and the absorbent paper used in the sanitary care products used above for reference, and measure the water absorption magnification in distilled water and artificial urine and the artificial urine in the form of a spot. A comparison was made regarding the differences when the liquid was added dropwise, and the results shown in Table 1 were obtained.

The laminated material of the present invention has a significantly thinner thickness, has a high water absorption capacity, and also maintains a high water retention capacity even under load.

In addition, when dripping in spots, the laminated material of the present invention first spreads over the entire surface in a flat manner, and then is absorbed by the lower layer, and also exhibits excellent water retention under load. However, in the case of general absorbent paper, it permeates both in the planar direction of the paper and in the back direction as well, so that it is absorbed only in a circular area centered around the dripping point, and it seeps out due to the load. It is something.

From the above, the laminated material of the present invention can be made extremely thin while maintaining excellent water absorption and water retention properties, and is suitable for use as sanitary napkins for women and disposable diapers for infants.

However, the water absorption ratio was calculated as shown in (1) below, and the artificial urine used was formulated as shown in (2) below.

(1) Water absorption capacity Laminated materials of the present invention were obtained in the same manner as above using the water-swellable copolymers of Reference Examples 2 to 8.

These materials also showed excellent effects similar to those mentioned above.

Example 2 Example 10 Instead of paper, Reference Examples 1 to 8 were used on a nonwoven fabric made of cotton and rayon cut to the size of a bed sheet.
A urethane solution in which the water-swellable copolymer obtained in Example 1 was dispersed was applied, and a nonwoven fabric (thickness of about 0.25 mm
A laminated material of the present invention was obtained, which had a polyurethane layer (about 0.5 mm thick) containing a water-swellable copolymer as a water-absorbing/water-retaining layer.

This material was suitable as a sweat absorbent disposable bedding for a patient's bed.

Example 3 Acrylic rubber [
Ptylated acrylate acrylic nitrile (88:12)
The fine powder of the water-swellable copolymers of Reference Examples 1 to 8 was finely and uniformly dispersed in the same manner as in Example 1 using a 20% toluene solution of the copolymer] and toluene instead of dimethylformpamide. An acrylic rubber solution was obtained.

25cm wide highly absorbent paper (about 0.3mm thick)
), and after air drying, the solvent was removed by heating and drying at 130° C. to obtain a laminated material (about 1.1 mm thick) of the present invention.

This material has excellent water absorption and water retention properties and is suitable for use as a compact and lightweight paper diaper.

Example 4 An acrylic rubber solution in which the water-swellable copolymer obtained in Example 2 was uniformly dispersed was applied to a nonwoven fabric (thickness: approximately 0.25 mm) made of cellulose fibers, and heated and dried to form a water-absorbing material. Laminated materials of the invention useful as high bedding (thickness approximately Q.
8 mm) was obtained.

Example 5 10 parts of the water-swellable copolymers obtained in Reference Examples 1 to 8 and 1 part of nonionic surfactant were added to 100 parts of ethyl acetate, followed by high-speed stirring while adding 30 parts of water dropwise.

The above suspension was gradually added to 200 parts of a 10% ethyl acetate solution of acrylic rubber (containing hydroxyl groups and consisting of an ethyl acrylate polymer) while stirring, and the water-absorbed water-swellable copolymer was uniformly and finely dispersed. An acrylic rubber solution was obtained.

Apply this to highly absorbent paper (about 0.3 mm thick),
After air drying, pre-dry at 60°C for 30 minutes, then at 110°C.
The mixture was dried by heating for 1 hour to remove residual moisture absorbed in the water-swellable copolymer, thereby obtaining a sheet-like laminated material of the present invention (about 1.2 mm thick).

The sheet obtained above has a porous structure, so it absorbs water very quickly, and since it contains a water-swellable copolymer, it has excellent water retention, making it suitable for use as disposable diapers or paper rags. Met.

Example 6 A sheet (with a thickness of approximately 0.0
．． 5 mm) and nonwoven fabric made of cotton fiber (thickness 0, 2
5mm), 150℃, 20kg/cm2, 2
The laminated sheet of the present invention was obtained by heat-pressing under conditions of Q seconds.

This laminated sheet showed excellent effects against force or load, had good water absorption, and was suitable as a sweat-absorbing sheet.

Example 7 60 parts of the water-swellable copolymers obtained in Reference Examples 1 to 8, 15 parts of liquid paraffin, 5 parts of polyptene, and styrene-butadiene type thermoplastic rubber (polystyrene content 30%) 4
0 part was pre-kneaded in a Banbury mixer, heated and melted using a calendar roll into a nonwoven fabric (thickness: approximately 0.25 mm) made of cotton and viscose rayon, and laminated to form the laminated sheet of the present invention (thickness: about 0.75 mm) was obtained.

This sheet was suitable as a disposable bed sheet as it exhibited excellent sweat absorption and load resistance effects.

Example 8 27 parts of the water-swellable copolymer obtained in Reference Examples 1 to 8, 10 parts of a 30% methyl ethyl ketone-toluene mixed solvent solution of a one-component polyurethane resin, and 86 parts of methyl ethyl ketone were uniformly mixed, and glass beads were added. The mixture was dispersed in a paint shaker for 2 hours to obtain a solution in which the water-swellable copolymer was finely dispersed.

Spread this on highly water-absorbent paper (0.15 mm thick) about 1 inch thick.
It was coated to a diameter of 1 mm and dried by heating at 80° C. for 10 minutes.

Next, a 15% toluene solution of ethylene-vinyl acetate copolymer was sprayed onto the polyurethane layer at a rate of 1070 per square meter, and dried at 80°C for 30 minutes to form a laminated sheet of the present invention (approximately 0.7 mm thick). I got it.

The laminated sheet obtained as described above has a paper with high water absorption and excellent dispersibility in the upper layer, a polymer layer with excellent water retention in the middle layer, and a waterproof and leak-proofing layer in the lower layer. This material was suitable for use as a sanitary napkin.

Claims (1)

[Scope of Claims] 1. In a water-absorbing/water-retaining laminated material formed by laminating a layer having water-absorbing and water-retaining properties and a diffusion layer having water-insoluble and water-permeable properties, the layer having water-absorbing and water-retaining properties is consisting of a substantially hydrophobic natural or synthetic rubber material and a water-swellable polymeric material, characterized in that the particles of the water-swellable polymeric material are dispersed in a continuous phase consisting of the natural or synthetic rubber material. Water-absorbing and water-retaining laminated material. 2. The water-swellable polymeric material is a water-swellable copolymer having at least one (hydrophobic constraint segment H hydrophilic segment)-{hydrophobic constraint segment) bond type in its structure. Laminated material according to scope 1.