JPH0827372A - Water-absorbing resin composition - Google Patents

Abstract

PURPOSE:To obtain a water-absorbing resin composition excellent in diffusibility of absorbed water, therefore resistant to the formation of unwetted agglomerates and gel blocking and satisfactory in handleability and processability by mixing a specified compound with a water-absorbing polymer. CONSTITUTION:This composition is prepared by mixing a poly-dioxolane desirably having a number-average molecular weight of 5000-10000000 (e.g. polydioxolane obtained by polymerizing 1,3-dioxolane) with a water-absorbing polymer (e.g.-crosslinked partially neutralized polyacrylate) desirably having a mean particle diameter of 10mum to 1mm. It is desirable that this composition is obtained by dispersing the water-absorbing polymer in the matrix of the polydioxolane. Alternatively, it is obtained by dispersing and firmly fixing the water-absorbing polymer on the surface of the matrix of the polydioxolane.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a water absorbent resin composition. More specifically, the present invention relates to a water absorbent resin composition which is easily handled and has excellent water absorbing performance.

[0002]

2. Description of the Related Art In recent years, water-absorbent polymers capable of absorbing hundreds of times their own weight of water have been developed and used for sanitary materials such as diapers and napkins, and waterproof tape for cables. However, since many water-absorbent polymers are powdery, they are difficult to handle as they are. Therefore, they are mixed with pulp, dispersed in rubber, or used as a base material with an adhesive or a hydrophobic binder. It is used by fixing to.

However, since the rubber and the adhesive are hydrophobic, there is a problem that the water absorbing performance of the water absorbing polymer is impaired.

Further, coating compositions prepared by blending a water-absorbing polymer in polyethylene oxide, which is a water-soluble polymer, are also known (JP-A-57-168921 and JP-A-1-182362). Further, a waterproof material for cables is known, in which a water-absorbing polymer is attached to a substrate by using polyethylene oxide as a binder (Japanese Patent Laid-Open No. 63-63).
75713).

However, since polyethylene oxide hinders the water absorption performance of the water-absorbent polymer, the water absorption speed is slowed down, and the water absorption performance has not been sufficiently exhibited.

[0006]

Therefore, an object of the present invention is to provide a novel water absorbent resin composition.

Another object of the present invention is to provide a water-absorbent resin composition which is easy to handle and has excellent water absorption performance.

[0008]

The above objects are achieved by a water-absorbent resin composition containing polydioxolane and a water-absorbent polymer.

The present invention is also the above water-absorbent resin composition comprising a water-absorbing polymer dispersed in a polydioxolane matrix. The present invention is the water absorbent resin composition, further comprising a water absorbent polymer dispersed and fixed on the surface of the polydioxolane matrix. The present invention is the water-absorbent resin composition, wherein the composition is in the form of a sheet, a film or a fiber. The present invention is also the above water-absorbent resin composition in which the surface of the water-absorbent polymer is coated with polydioxolane. The present invention further provides the above water-absorbent resin composition, wherein the water-absorbent polymer forms an aggregate or a granule using polydioxolane as a binder.

[0010]

The water absorbent resin composition according to the present invention comprises polydioxolane and a water absorbent polymer.

The form of the water absorbent resin composition may be a simple mixture of polydioxolane and a water absorbent polymer, or may be, for example, the form shown below.

(1) A water-absorbent resin composition in which a water-absorbent polymer is dispersed in a polydioxolane matrix.

(2) A water absorbent resin composition in which a water absorbent polymer is dispersed and fixed on the surface of a polydioxolane matrix.

(3) A water absorbent resin composition obtained by coating the surface of a water absorbent polymer with polydioxolane.

(4) A water-absorbent resin composition comprising a water-absorbent polymer as an aggregate or granules using polydioxolane as a binder.

However, the form of the water absorbent resin composition according to the present invention is not limited to these forms.

As the method for obtaining the polydioxolane used in the present invention, for example, 1,3-dioxolane, 2-
Methyl-1,3-dioxolane, 4-methyl-1,3-
At least one monomer selected from monomers such as dioxolane and 2-2′-diethyl-1,3-dioxolane may be cationically polymerized. Further, other monomers copolymerizable with these monomers may be copolymerized. Examples of the copolymerizable monomer include styrene; (meth) acrylic acid;
Unsaturated hydrocarbons such as ethylene and propylene; cyclic ethers such as trioxane, ethylene oxide, propylene oxide and tetrahydrofuran; γ-butyrolactone,
Lactones or lactams such as glycolide, lactide, ε-caprolactone, ε-caprolactam can be mentioned.

Polydioxolane can also be obtained by polycondensation of formaldehyde and ethylene glycol.

The polydioxolane used in the present invention is not limited to those obtained by these methods, but a typical example thereof is oxymethylene-oxy represented by the following general formula (I). Some have repeating units of ethylene.

[0020]

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(In the formula, R ^{1 to} R ⁶ are each independently a hydrogen atom, a methyl group or an ethyl group.) Examples of the initiator include heteropolyacids such as phosphotungstic acid and phosphomolybdic acid, and triethyl. Organometallic compounds such as aluminum, aluminum isopropoxide, and titanium isopropoxide can be used. It can also be obtained by polycondensation of formaldehyde and ethylene glycol. The polydioxolane used as a matrix in the present invention has an average number molecular weight of 5,000.
It is 0 to 10,000,000, preferably 10,000 to 1,000,000.

The polydioxolane used in the present invention is not limited to those obtained by these methods.

As the water-absorbent polymer used in the present invention, conventionally known ones can be used, and examples thereof include cross-linked polyacrylic acid partially neutralized products, starch-acrylic acid graft polymers, starch-acrylonitrile graft polymers. , A hydrolyzate of vinyl acetate-acrylic acid ester copolymer, a hydrolyzate of an acrylonitrile copolymer or an acrylamide copolymer or a crosslinked product thereof, an isobutylene-maleic anhydride copolymer crosslinked product, (meth) Acrylate- (meth) acrylamide copolymer cross-linked product, (meth)
Acrylamide-2-methylpropane sulfonate copolymer cross-linked product, alkoxy polyethylene glycol (meth)
Examples include acrylate copolymer crosslinked products, polyvinyl alcohol crosslinked products, modified polyethylene oxide crosslinked products,
One or more of these polymers may be mentioned. Among these, a crosslinked polyacrylic acid partially neutralized product is most preferable. The shape of the water-absorbent polymer is not particularly limited, and generally includes an amorphous shape, a spherical shape, a scaly shape, a lump shape, a fibrous shape and the like. The average particle size is, for example, 1 μm to 10 mm, preferably 10 μm to 1 mm. As the water-absorbent polymer, a granulated product in which the primary particles are aggregated can also be used. Also,
As the water-absorbent polymer, a surface-crosslinked one may be used. Surface cross-linking is a water-absorbing polymer such as a polyhydric alcohol, a polyvalent epoxy compound, a polyvalent amine, or a polyvalent metal salt capable of forming a covalent bond or an ionic bond with a functional group of a water-absorbing polymer such as a carboxyl group. It is made by reacting with and near the surface of the water-absorbent polymer. The water-absorbent polymer that can be used in the present invention is not limited to the above polymers.

The average particle diameter of the water-absorbent polymer at the time of surface cross-linking is 1 to 1000 μm, preferably 10 to 850 μm, and the average particle diameter is 20 to 1000 μm, preferably primary particles aggregated by the surface treatment. Is 30-850μ
m.

As the cross-linking agent used for surface cross-linking, for example, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, glycerin, polyglycerin, propylene glycol, diethanolamine, triethanolamine, polypropylene glycol, polyvinyl alcohol, pentaerythritol, 1 , 4-butanediol, 1,5-pentanediol, 1,6-hexanediol, sorbit, sorbitan, glucose, mannitol, mannitane, sucrose,
Polyhydric alcohols such as glucose; polyhydric glycidyl compounds such as ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin triglycidyl ether; haloepoxy compounds such as epichlorohydrin, α-methylchlorohydrin; glutaraldehyde, glyoxal, etc. Polyaldehydes; polyvalent amine compounds such as ethylenediamine and polyethyleneimine; calcium hydroxide, calcium chloride, calcium carbonate, calcium oxide, magnesium borax magnesium, magnesium oxide, aluminum chloride, zinc chloride and nickel chloride, etc. Hydroxides, halides, carbonates, oxides, borax, etc. of Group 3B and Group 8 metals,
Examples thereof include polyvalent metal compounds such as aluminum isopropylate, and one or more of these can be appropriately selected and used in consideration of reactivity. Among these, from the strength of the particle structure of the water-absorbent polymer crosslinked near the surface of the particles obtained, when the water-absorbent polymer has a carboxyl group, as a crosslinking agent, a polyhydric alcohol compound, It is preferable to use a polyvalent glycidyl compound or the like.

The water absorbing polymer used in the present invention has a water absorption capacity (g / g) of 5 to 1000, preferably 10 to 500.
Is.

The shape of the water absorbent resin composition in which the water absorbent polymer is dispersed in the polydioxolane matrix is as follows:
Without particular limitation, for example, film-like, sheet-like, fiber-like,
Examples include lumps and liquids. The water-absorbent polymer is dispersed in the matrix, but a part of it may be exposed on the surface. Although polydioxolane is water-soluble, it hardly dissolves at room temperature and easily dissolves in warm water of 50 to 60 ° C. Therefore, when the water-absorbent resin composition absorbs water, other water-soluble polymers such as polyethylene oxide inhibit water absorption of the water-absorbent polymer, but do not inhibit the water-absorbent property of the water-absorbent polymer. . Therefore, such a water-absorbent composition becomes a water-absorbent resin composition having good water absorbability and handleability.

Such a composition can be obtained, for example, by polymerizing dioxolane in the presence of a water-absorbing polymer, mixing polydioxolane and the water-absorbing polymer, and then molding the mixture into a desired shape. Preferred is a method in which polydioxolane and a water-absorbent polymer are mixed and molded. Specifically, a method of melt-kneading polydioxolane and a water-absorbent polymer under heating, forming into a film or sheet by an inflation method or a T-die method, or spinning to form a fiber, or Examples thereof include a method in which polydioxolane is dissolved in a solvent such as water or chloroform, and then a water-absorbent polymer is dispersed, and this is applied or spun. By stretching the obtained film, sheet or fiber, a tough film, sheet or fiber can be obtained. It is also possible to spray a water-absorbing polymer between two polydioxolane films or sheets and heat press. The thickness of the obtained film or sheet is generally in the range of 1 μm to 10 mm. When the thickness is less than 1 μm, the strength is poor, and when it is more than 10 mm, the water absorption speed may be very slow. The fiber diameter is generally in the range of 1 μm to 2 mm, preferably 10 to 1000 μm. The thickness of the film or sheet and the diameter of the fiber are not limited to these ranges.

The ratio of the polydioxolane to the water-absorbing polymer in this composition can be appropriately set depending on the purpose and application, but generally it is within the range of 1 to 2000 parts by weight of the water-absorbing polymer with respect to 100 parts by weight of polydioxolane. Yes, preferably 5
The range is up to 1000 parts by weight. If the amount of the water-absorbent polymer is less than 1 part by weight, sufficient water absorption performance may not be exhibited, while if it exceeds 2000 parts by weight, the strength may be weakened.

Inorganic particles, pulp fibers, surfactants, etc. may be added to the composition in which the water-absorbent polymer is dispersed in the polydioxolane matrix in order to improve the water absorption rate. These additives may be added to either the polydioxolane matrix or the water absorbing polymer. The shape of the water-absorbent polymer is not particularly limited, but if the shape is spherical, a composition having a smoother surface can be obtained as compared with the case of using an amorphous polymer.

The inorganic particles used as an additive have an average particle size of 0.001 to 10 μm, preferably 0.0
The particle size is 1 to 1 μm, and examples thereof include fine silica powder, talc, titanium oxide, zinc oxide, magnesium oxide, calcium carbonate, diatomaceous earth, and iron powder. 0.0001 to 50% by weight relative to the composition, preferably 0.001 to 2
0% by weight is used.

The pulp has an average particle size of 10 to 5
00 μm, preferably 10 to 300 μm,
Examples include linter pulp, wood pulp, synthetic pulp and the like. It is used in an amount of 0.1 to 50% by weight, preferably 1 to 20% by weight, based on the composition.

Examples of the surfactant include nonionic surfactants represented by polyoxyalkylene alkyl ethers and polyoxyalkylene acyl ethers, anionic surfactants represented by alkylbenzene sulfonates, and alkylammonium. There are cationic surfactants typified by salts and the like.
10% by weight, preferably 0.1-5% by weight is used.

The water-absorbent resin composition obtained by dispersing the water-absorbent polymer in the polydioxolane matrix obtained as described above, when the water-absorbent polymer comes into contact with the water-soluble liquid,
Since the polydioxolane does not hinder the water absorption of the water-absorbing polymer, the swollen polymer causes the composition to break down, the aqueous liquid diffuses throughout, and the liquid is quickly absorbed. Further, since polydioxolane has low hygroscopicity even in a high humidity atmosphere, such a water-absorbent resin composition has no stickiness or tackiness on the surface and is easy to handle. This water-absorbent resin composition can be easily processed into a shape such as a film, a sheet, a fiber, and a bag, and such a shape has good handleability. Further, it is possible to easily form a composite with another thermoplastic resin. Further, it can be easily formed into a composite with another substrate by thermal processing. Since it has excellent water absorbency and good workability, it can be suitably used as an absorbent or diffusing material for sanitary materials, a water blocking material for communication cables, and the like. Further, since it is also excellent in water-disintegrating property, it can be suitably used for packaging water-soluble substrates or water-dispersed substrates such as pharmaceuticals, agricultural chemicals, fertilizers, surfactants, detergents and pigments.

The water-absorbent resin composition in which the water-absorbent polymer is dispersed in the polydioxolane matrix is heated or liquefied by a solvent or the like to give the water-absorbent resin composition a nonwoven fabric or a film. It can also be applied to other base materials such as to form a composite.

Such a composite has a water-absorbing polymer fixed to a substrate by using polydioxolane as a binder, and has excellent water-absorbing property as compared with a conventional one using a hydrophobic adhesive or binder. Will be things.

In the present invention, a water absorbing composition having a water absorbing polymer fixed on the surface of a polydioxolane matrix is also a preferred form. This water-absorbent resin composition is obtained by polymerizing a monomer to be a water-absorbent polymer in the presence of polydioxolane, or molding polydioxolane into a desired shape, and then contacting the water-absorbent polymer with the matrix surface thereof, It can be obtained by a method of embedding the water-absorbing polymer on the surface of the polydioxolane matrix, or by fixing it through a binder such as an adhesive. Preferably, the water-absorbing polymer is fixed by being embedded in the surface of the polydioxolane matrix without using a binder or the like. This is obtained by, for example, molding polydioxolane into a film, sheet or fiber, and then spraying a water-absorbent polymer thereon or mixing it with a water-absorbent polymer,
The polydioxolane and the water-absorbent polymer are brought into contact with each other, and then heated to soften the polydioxolane to embed the water-absorbent polymer on the matrix surface and fix it to the surface. It is also possible to soften the polydioxolane with a solvent and then bring it into contact with the water-absorbing polymer to fix it on the surface.
The water-absorbent polymer may be partially embedded in the matrix.

The ratio of the polydioxolane to the water-absorbing polymer can be appropriately set depending on the purpose and application, but generally 1 to 20 parts by weight of the water-absorbing polymer are used per 100 parts by weight of polydioxolane.
It is in the range of 00 parts by weight, preferably in the range of 5 to 1000 parts by weight. The particle size and shape of the water-absorbent polymer are not particularly limited, and the particle size is generally in the range of 1 to 1000 μm, preferably 10 to 850 μm. Polymers having various shapes such as an amorphous shape, a spherical shape, a scaly shape, and a fibrous shape can be used. The water-absorbent polymer may be surface-crosslinked. Further, in order to improve the water absorption rate and diffusibility, additives such as inorganic fine particles, surfactants, pulp fibers and the like may be added.

In the water-absorbent resin composition thus obtained, since the water-absorbent polymer is fixed on the surface of the matrix, the water-absorbing speed is high, and the dampness is less likely to occur, and the diffusibility is good. When it comes into contact with the liquid, it quickly diffuses throughout and the liquid is absorbed quickly. Further, by forming it into a film, a sheet, or a fiber, the handleability and processability are improved. Further, since polydioxolane has thermoplasticity, it becomes easy to form a composite with another thermoplastic resin. Further, the water absorbent resin composition itself can be easily processed.

Another preferred embodiment of the present invention is a water absorbent resin composition in which the surface of a water absorbent polymer is coated with polydioxolane. This product is obtained by melt-kneading polydioxolane and a water-absorbing polymer, dissolving polydioxolane in chloroform or water and then dispersing the water-absorbing polymer to remove the solvent, or dispersing in a melted polydioxolane or solvent. It can be obtained by spraying polydioxolane on a water-absorbing polymer. It can also be obtained by polymerizing 1,3-dioxolane in the presence of a water-absorbing polymer, or by polymerizing a starting material of the water-absorbing polymer in the presence of polydioxolane. The ratio of the water absorbent polymer to the polydioxolane is generally 0.01 to 50 parts by weight, preferably 0.1 to 20 parts by weight, based on 100 parts by weight of the water absorbent polymer. The particle size and shape of the water-absorbent polymer are not particularly limited, and the particle size is generally 1 to 100.
It is in the range of 0 μm, preferably in the range of 10 to 850 μm. Polymers having various shapes such as amorphous, spherical, scale-like, and fibrous can be used. Further, the water-absorbent polymer may be surface-crosslinked.
Further, in order to improve the water absorption rate and diffusibility, inorganic fine particles, additives such as surfactants and pulp fibers may be added to the water absorbing composition.

When the surface of the water-absorbent polymer is coated with polydioxolane, the polydioxolane does not have tackiness even when it absorbs moisture, so that the water-absorbent polymer may cause coating when it absorbs moisture. There is no. In addition, when it absorbs moisture, the fluidity is good and the handleability is good. Further, when it comes into contact with an aqueous liquid, the residue or gel blocking hardly occurs, and it can be suitably used as an absorbent for gelling agents, absorbent for sanitary materials, and the like.

As one of the preferred embodiments of the present invention,
An example is a water-absorbent composition in which the water-absorbent polymer is aggregated or formed into granules using polydioxolane as a binder. For example, polydioxolane and a water-absorbing polymer are melt-kneaded under heating and crushed to a desired size, or polydioxolane is dissolved in a solvent such as chloroform or water and mixed with the water-absorbing polymer. Then, the solvent is removed, and the product is crushed to a desired size. It can also be obtained by polymerizing 1,3-dioxolane in the presence of a water-absorbing polymer, or by polymerizing a starting material of the water-absorbing polymer in the presence of polydioxolane.
The ratio of the water-absorbent polymer and the polydioxolane is generally 0.09% of the polydioxolane based on 100 parts by weight of the water-absorbent polymer.
1 to 50 parts by weight, preferably 1 to 20 parts by weight. The size of the obtained aggregate or granule is not particularly limited,
It can be appropriately set depending on the particle size and shape of the water-absorbing polymer to be used and its use and purpose, but in the case of a granulated product, 10 to 1000 μ
m, preferably 20 to 850 μm, and in the case of agglomerates, the thickness is 0.1 to 5 mm, preferably 0.1 to 2 mm.
The range is mm. Polymers having various shapes such as an amorphous shape, a spherical shape, a scaly shape, and a fibrous shape can be used.

The water-absorbent polymer may be surface-crosslinked. Then, in order to improve the water absorption rate and the diffusibility, the above-mentioned inorganic fine particles, an additive such as a surfactant and pulp fiber may be added to the water absorbing composition.

This water-absorbent resin composition has excellent water-absorbing properties, because polydioxolane, which is a binder, does not impair the water-absorbing property of the water-absorbing polymer, and thus does not cause a trapping phenomenon during water absorption. . In addition, when water-absorbing polymers having a relatively small particle size are aggregated, the water-absorbing rate is higher than that of water-absorbing polymers having the same size.

When the water-absorbent polymer having a small particle size is granulated, fine powder of the water-absorbent polymer is not required to be handled, so that workability and handleability are improved. It is also possible to prevent the dust from floating. Further, unlike other water-soluble polymers such as polyethylene oxide, polydioxolane does not exhibit tack at the time of moisture absorption, so that the hygroscopic fluidity becomes good. Since polydioxolane has thermoplasticity, it can be easily combined with another material by heating.

Various additives can be added to the water absorbent resin composition of the present invention. As the additive, silica fine particles, titanium oxide, zinc oxide, magnesium oxide, calcium carbonate, talc, diatomaceous earth, etc., inorganic fine particles represented by iron powder, organic fine particles, filler, sorbitan fatty ester, sucrose fatty acid ester, poly Surfactants represented by oxyalkylene alkyl ethers, polyoxyalkylene acyl esters, etc., fungicides represented by tetrachloroisophthalonitrile, thiabendazole, zinc pyrithione, etc., antibacterial agents, preservatives, represented by metal phthalocyanines, etc. Deodorant, plasticizer represented by glycerin, polyethylene glycol, dioctyl phthalate, etc.,
Guanidine sulfamate and its derivatives, guanidine phosphate and its derivatives, flame retardants typified by phosphoric acid esters such as triethyl phosphate and trischloroethyl phosphate, deliquescent inorganic salts such as lithium chloride, magnesium chloride and calcium chloride, Hygroscopic agents represented by sodium lactate, synthetic polymers such as hydroxyethyl cellulose, carboxymethyl cellulose, polyvinyl alcohol, polyacrylic acid salts, various pharmaceuticals, agricultural chemicals, fertilizers, coloring agents, pulp, activated carbon, gas adsorbents and the like. . The amount of these additives added is not particularly limited,
Generally, 0.0001 to 1 to 1 part by weight of the water absorbing composition
It is in the range of 00 parts by weight, preferably 0.001 to 10
The range is parts by weight.

[0047]

The present invention will be further described below with reference to examples, but the present invention is not limited to these examples.

Reference Example 1 A four-necked flask equipped with a stirrer, a thermometer, a nitrogen introducing tube and a cooling tube was purged with nitrogen to obtain 60 g of 1,3-dioxolane.
Was introduced and the system was kept at 0 ° C. Next, 0.3 ml of a 5% phosphotungstic acid / acetone solution was added with stirring under a nitrogen atmosphere to initiate polymerization. After the heat generated by the polymerization reached a peak, 1 ml of triethylamine was added to stop the reaction.

The obtained dioxolane solution of polydioxolane was dried in a vacuum dryer at 100 ° C. for 5 hours to obtain polydioxolane (1).

The polystyrene equivalent number average molecular weight of the obtained polydioxolane (1) was 100,000.

Reference Example 2 N, N'-methylenebisacrylamide 0.1% was added to a monomer aqueous solution (monomer concentration 37% by weight) of partially neutralized sodium acrylate in which 75% was neutralized with sodium hydroxide.
Mol% (to sodium acrylate monomer) and sodium persulfate 1 g / mol (to sodium acrylate monomer) were added, and then dissolved oxygen was removed from the aqueous monomer solution with nitrogen gas. This monomer aqueous solution was dropped onto a stainless steel belt heated to 120 ° C. under a nitrogen atmosphere to perform thin film polymerization. The polymer after polymerization was scraped off from the belt, dried and then pulverized to obtain a water-absorbent polymer (A). This product has a water absorption capacity of 40
(G / g), the water absorption capacity of pure water was 300 (g / g).

Subsequently, this was sieved with a 200-mesh sieve to obtain a water-absorbent polymer (A-1).

Reference Example 3 100 parts of the water-absorbent polymer (A) obtained in Reference Example 2 was mixed with 0.1 part of ethylene glycol diglycidyl ether, 5 parts of water and 1 part of isopropyl alcohol, and the resulting mixture was dried. Heat treatment was carried out in the machine at 100 ° C. for 30 minutes to obtain a water absorbent polymer (B). The water absorption capacity of this product is 38 (g / g), and the water absorption capacity of pure water is 280 (g / g).
g).

Subsequently, this product was treated with 200 mesh, 14
Sieving with a 0 mesh or 100 mesh sieve gave water-absorbent polymers (B-1), (B-2) and (B-3).

Reference Example 4 Polyethylene glycol diacrylate (average ethylene oxide chain number: 8) was added to an aqueous monomer solution of partially neutralized sodium acrylate 75% neutralized with sodium hydroxide (monomer concentration 37% by weight). 0.1 mol% (to sodium acrylate monomer) and sodium persulfate 0.02
g / mol (to sodium acrylate monomer) was added,
Then, dissolved oxygen in the monomer aqueous solution was removed with nitrogen gas.

1 liter of cyclohexane was placed in a 2-liter four-necked separable flask equipped with a stirrer, a reflux condenser, a thermometer, a nitrogen gas introducing tube and a dropping funnel, and 4 g of sorbitan monostearate was added as a dispersant.
Nitrogen gas was blown in to drive out the dissolved oxygen.

Then, the temperature of cyclohexane is set to 55.degree.
The temperature was raised to 1, the above aqueous monomer solution was added dropwise, and the mixture was dispersed by stirring at 200 rpm. After that, the bath temperature was kept at 55 ° C. to start the polymerization reaction, and then this temperature was kept for 1 hour to complete the polymerization. After completion of the polymerization, most of the water was removed by azeotropic dehydration, followed by filtration and further drying under reduced pressure at 80 ° C. to obtain an absorbent polymer (C). The water absorption capacity of this product was 45 (g / g), and the water absorption capacity of pure water was 350 (g / g).

Subsequently, this was sieved with a 200-mesh sieve to obtain a water-absorbent polymer (C-1).

Example 1 10 parts by weight of the polydioxolane (1) obtained in Reference Example 1 was added to 40 parts by weight of chloroform and dissolved, and then 10 parts by weight of the water-absorbent polymer (A-1) obtained in Reference Example 2 was added. The mixture was uniformly dispersed. This was coated on a release paper with a bar coater, chloroform was removed, and the release paper was peeled off to obtain a water absorbent resin composition (1) of the present invention. The thickness of the obtained water absorbent resin composition was 100 μm. The absorption rate of the resulting water absorbent composition is shown in Table 1.

The absorption rates shown in Table 1 were measured by the following method.

(Absorption rate) 1 ml of physiological saline (0.9 wt% sodium chloride aqueous solution) was added to the water absorbing composition cut into a diameter of 45 mm, and the time taken for the physiological saline to be absorbed by the water absorbing composition was measured. , The absorption rate was determined.

Examples 2 to 4 In place of the water absorbent polymer (A-1) in Example 1, the water absorbent polymers (B-1), (B-2) and (B-3) obtained in Reference Example 3 were used. ) And were used in the same manner as in Example 1 to obtain water-absorbent resin compositions (2) to (4) of the present invention. The water-absorbent resin compositions (2) to (4) obtained had thicknesses of 100, 210, and 250 μm, respectively.
The absorption rate of the resulting water absorbent resin composition is shown in Table 1.

Example 5 Except that the water absorbent polymer (A-1) in Example 1 was replaced by the water absorbent polymer (C-1) obtained in Reference Example 4,
Similar to Example 1, the water absorbent resin composition (5) of the present invention
I got The thickness of the resulting water absorbent resin composition (5) was 11
It was 0 μm. This film was a film having a smooth surface and a good texture. The absorption rate of the resulting water absorbent resin composition is shown in Table 1.

Example 6 Example 1 was repeated except that 0.5% by weight of silica fine particles (trade name A-200: manufactured by Nippon Aerosil Co., Ltd.) was added to the water absorbent polymer (A-1). A water-absorbent resin composition (6) of the present invention was obtained in the same manner as in. The thickness of the resulting water absorbent resin composition (6) was 90 μm. The absorption rate of the resulting water absorbent resin composition is shown in Table 1.

Example 7 A water absorbent resin composition (7) of the present invention was obtained in the same manner as in Example 1 except that 50 parts by weight of the water absorbent polymer (A-1) was added. The water absorbent resin composition (7) obtained had a thickness of 200 μm. The absorption rate of the resulting water absorbent resin composition is shown in Table 1.

Example 8 The water absorbent polymer (A-1) in Example 1 was replaced by finely pulverized water absorbent polymer (A) and sieved with a 400 mesh sieve (A-4). , And an average particle diameter of 20 μm) were used to obtain a water absorbent resin composition (8) of the present invention in the same manner as in Example 1. The water absorbent resin composition (8) thus obtained had a thickness of 30 μm. The absorption rate of the resulting water absorbent resin composition is shown in Table 1.

Example 9 To 10 parts by weight of the polydioxolane (1) obtained in Reference Example 1 was added 5 parts by weight of the water-absorbing polymer (A-1) obtained in Reference Example 8
The mixture was kneaded by heating at 0 ° C. This was hot-pressed at 120 ° C. to obtain a water absorbent resin composition (9) of the present invention. The water absorbent resin composition (9) obtained had a thickness of 50 μm. The absorption rate of the resulting water absorbent resin composition is shown in Table 1.

Comparative Examples 1-3 Polydioxolane (1) in Examples 1, 2 and 5
Of polyethylene oxide (average molecular weight 15-
Comparative water-absorbent resin compositions (1), (2) and (3) were obtained in the same manner except that (400,000) was used. The thickness of the obtained comparative water absorbent resin composition was 100 and 1 respectively.
10 and 110 μm. The comparative water absorbent resin composition thus obtained is the water absorbent resin composition (1) to (9) of the present invention.
Compared with, it was tacky to the touch with fingers and had tackiness. The absorption rate of the obtained comparative water absorbent resin composition is shown in Table 1.

Example 10 40 parts by weight of chloroform was added to 10 parts by weight of the polydioxolane (1) obtained in Reference Example 1 and dissolved, and the solution was coated on a release paper with a bar coater. Subsequently, 5 parts by weight of the water-absorbent polymer (B-3) obtained in Reference Example 3 was sprayed and dried to remove the solvent, to obtain a water-absorbent resin composition (10) of the present invention. The thickness of this product was 140 μm. The absorption rate of the resulting water absorbent resin composition is shown in Table 1.

Example 11 The polydioxolane obtained in Reference Example 1 was formed into a film by the T-die method. This film was heated to 80 ° C. to soften the film surface, and then the water-absorbent polymer (B-3) was sprayed to obtain the water-absorbent resin composition (11) of the present invention. The thickness of this product was 200 μm. The absorption rate of the resulting water absorbent resin composition is shown in Table 1.

Comparative Example 4 Example 11 was repeated except that polyethylene oxide (1) was used in place of polydioxolane (1) in Example 11.
A comparative water absorbent resin composition (4) was obtained in the same manner as in. This had a thickness of 130 μm. The absorption rate of the obtained comparative water absorbent resin composition is shown in Table 1.

[0072]

[Table 1]

Example 12 To 10 parts by weight of the polydioxolane (1) obtained in Reference Example 1 was added 5 parts by weight of the water-absorbing polymer (B-1) obtained in Reference Example 3 to give 8 parts.
The mixture was kneaded by heating at 0 ° C. This was extruded from a 0.1 mm die to obtain a fibrous water absorbent resin composition (12). When 0.1 g of this water absorbent resin composition was immersed in 1 ml of physiological saline, it absorbed water in 20 seconds.

Example 13 10 parts by weight of the polydioxolane (1) obtained in Reference Example 1 was added to 500 parts by weight of chloroform and dissolved, and then 100 parts by weight of the water-absorbing polymer (A) obtained in Reference Example 2 was added. After stirring, it was filtered. The residue was dried and crushed to obtain the water absorbent resin composition (13) of the present invention. This is VORTE shown below
When the X water absorption rate was measured, the water absorption rate was 12 seconds.

(VORTEX water absorption rate) 50 ml of physiological saline was added to a 100 ml beaker and stirred with a stirrer piece (stirring speed of 600 rpm). 2 g of the water absorbing composition was added thereto, and the time until the water absorbing composition swelled and the vortex disappeared was measured to determine the VORTEX water absorbing speed.

Comparative Example 5 The VORTEX water absorption rate of the water absorbent polymer (A) obtained in Reference Example 2 was 66 seconds.

Comparative Example 6 Example 1 was repeated except that polyethylene oxide (1) was used instead of polydioxolane (1) in Example 13.
Comparative water absorbent resin composition (5) was obtained in the same manner as in 3. This product had a VORTEX water absorption rate of 90 seconds.

Example 14 The polydioxolane obtained in Reference Example 1 was dissolved in warm water at 60 ° C. to prepare a 10 wt% aqueous solution of polydioxolane. Water-absorbent polymer (B) obtained in Reference Example 3 with 5 parts by weight of this aqueous solution
100 parts by weight was added with stirring, dried at 90 ° C., and then crushed to obtain a water absorbent resin composition (14) of the present invention. The VORTEX water absorption rate of this product was 10 seconds.

10 g of this water absorbent resin composition (14)
It was placed in a 00 ml beaker and shaken left and right, but no dust was generated. Continue this at a temperature of 25 ° C and a relative humidity of 60.
After being left for 8 hours in a constant temperature and humidity chamber, the beaker was tilted and flowed smoothly, and the fluidity was good.

Comparative Example 7 Example 1 was repeated except that polyethylene oxide (1) was used instead of polydioxolane (1) in Example 14.
Comparative water absorbent resin composition (6) was obtained in the same manner as in 4. This product had a VORTEX water absorption rate of 70 seconds.

10 g of this comparative water absorbing composition (6)
It was placed in a 0 ml beaker and shaken to the left and right, but almost no dust was generated. Continue this at a temperature of 25 ° C and a relative humidity of 6
After being left in a 0% constant temperature and humidity chamber for 8 hours, when the beaker was tilted, the polymer was integrated and solidified.

Comparative Example 8 100 ml of 10 g of the water-absorbent polymer (B) obtained in Reference Example 3
When placed in a beaker and shaken left and right, the polymer flew in and dust was generated. Subsequently, this was left for 8 hours in a thermo-hygrostat at a temperature of 25 ° C. and a relative humidity of 60%, and the beaker was tilted. As a result, the polymer was integrated and solidified.

[0083]

Since the water absorbent resin composition according to the present invention has the constitution as described above, it has the following advantages.

1. Since polydioxolane does not hinder the water absorption of the water-absorbing polymer, the diffusivity at the time of water absorption becomes good,
Since this generation and gel blocking can be prevented as it is, the water absorbent resin composition has excellent water absorbing properties.

2. Since polydioxolane has thermoplasticity, it can be easily processed and molded into various shapes such as a sheet shape, a film shape, a fibrous shape, a granular shape, and a bag shape depending on the purpose and application.

3. Since polydioxolane has thermoplasticity, it can be easily formed into a composite with another material, particularly a base material made of a thermoplastic resin.

4. When the shape of the water-absorbent resin composition is a sheet or film, the handling property is good without handling powders and the like.

5. Since polydioxolane has a film forming property, it can be easily formed into a film or a sheet, and the handleability becomes good.

6. When the water-absorbent resin composition is in a liquid state, a water-absorbent resin composite having good water-absorbent property can be easily obtained by applying it to another substrate.

7. Since polydioxolane has low hygroscopicity even in a high humidity atmosphere and does not show tackiness when it absorbs moisture,
Caking does not occur when moisture is absorbed, and the handleability is good. Further, the fluidity when absorbing moisture is also good.

8. Since it is composed of polydioxolane and a water-absorbing polymer, it is possible to prevent dust generation.

Therefore, the water absorbent resin composition of the present invention is
Not only hygiene materials such as paper diapers, napkins and bandages, but also food freshness retention, drip absorption, packaging materials, anti-condensation materials,
Water blocking materials for electric wires and communication cables, sealing materials, cold insulation materials,
Artificial snow, concrete admixture / modifier, absorption of cement breathing water, water retention material for agriculture and horticulture, water retention material for body warmers, oil dehydration material, battery separator, insole, deodorant, fragrance, artificial snow, soundproofing It can be used for various purposes such as materials, anti-vibration materials, artificial lenses, gels for artificial joints, polymers for drug delivery, and pap materials. The use of the water absorbent resin composition of the present invention is not limited to these uses.

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Claims (6)

[Claims] 1. A water absorbent resin composition comprising polydioxolane and a water absorbent polymer. 2. The water absorbent resin composition according to claim 1, wherein the water absorbent polymer is dispersed in a polydioxolane matrix. 3. The water absorbent resin composition according to claim 1, wherein the water absorbent polymer is dispersed and fixed on the surface of the polydioxolane matrix. 4. The water absorbent resin composition according to claim 1, wherein the composition has a sheet shape, a film shape, or a fibrous shape. 5. The water absorbent resin composition according to claim 1, wherein the surface of the water absorbent polymer is coated with polydioxolane. 6. The water-absorbent resin composition according to claim 1, wherein the water-absorbent polymer forms an aggregate or a granule using polydioxolane as a binder.