JPH07173385A - Water-absorbing resin composition - Google Patents

Abstract

PURPOSE:To obtain a composition good in processability and capable of giving molded products with high mechanical strength, elongation and water absorbing ability, etc., by incorporating a water-absorbing resin produced from a polyalkylene oxide, an active hydrogen compound and an NCO compound with a carboxyl-contg. copolymer. CONSTITUTION:This composition good in processability and capable of giving molded products with excellent mechanical strength, elongation, water absorbing ability and hydrophilicity, comprises (A) 100 pts.wt. of a polyalkylene oxide modified product as a water-absorbing resin which has 5000-1000000 poise in the melt viscosity at 170 deg.C under a load of 50kg/cm<2> and is produced by reaction of a polyalkylene oxide (e.g. polyethylene oxide) and an active hydrogen-contg. compound (e.g. 1,4-butanediol) with an isocyanate compound (e.g. 4,4'- diphenylmethane diisocyanate), (B) 10-5000 pts.wt. of a thermoplastic resin (e.g. low-density polyethylene), and (C) 1-100 pts.wt. of a copolymer of ethylene and carboxyl-contg. monomer (e.g. acrylic acid).

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a water absorbent resin composition, more specifically, used alone or in combination with other general-purpose resins, and processed into a form such as a film, a sheet, a fiber or a sealing material. The present invention relates to a water absorbent resin composition.

[0002]

2. Description of the Related Art Thermoplastic resins used in various forms are hydrophobic materials, and it is necessary to impart water absorption or water retention depending on the application.

Conventionally, as a method of imparting water absorption to the above-mentioned thermoplastic resin, for example, a method of chemically treating the surface thereof, a method of mixing a water-absorbing substance, and the like are known. As a method for imparting water retention to the thermoplastic resin, for example, many water-absorbent resin compositions have been proposed in which the water-absorbent resin is dispersed or melted and kneaded with the thermoplastic resin.

Most of such water-absorbent resin compositions are prepared by mixing a water-absorbent resin with a thermoplastic resin such as polyethylene or polypropylene, melt-kneading the mixture with a kneader, a Banbury mixer, an extruder or the like, and then molding it into pellets or the like. It can be obtained by crushing it.

However, the above-mentioned production method has a problem that in the kneading of the thermoplastic resin and the water-absorbing resin, the compatibility between the components is low and a uniformly dispersed product cannot be obtained.

In order to solve the above problems, JP-A-1-163229 discloses a uniform water-absorbent resin composition in which the compatibility between a polyolefin resin and a water-absorbent resin is improved.
It has been proposed to use a polyethylene oxide-modified water-absorbing resin and add a specific third component resin, particularly a polyamide or polyoxymethylene having a melting point of less than 200 ° C. to a resin composition.

However, the above-mentioned Japanese Patent Laid-Open No. 1-16322
Also in the method described in Japanese Patent Publication No. 9, depending on the type of the polyalkylene oxide-modified product used as the water absorbent resin,
Although the number of lumps on the appearance of the obtained molded product is reduced, and its size is also reduced, when the internal cross-section is observed in detail by an electron microscope, the water-absorbent resin is scattered, so that the processability is reduced and In some cases, the physical properties such as tensile strength and elongation are reduced, and in some cases, satisfactory performance in hydrophilicity, water absorption, etc. may not be exhibited.

The present inventors have previously proposed in JP-A-5-49179 a water-absorbent resin composition prepared by mixing a cross-linked polyalkylene oxide having a specific melt viscosity with a thermoplastic resin as a water-absorbent resin. However, also in the composition, when a crosslinked polyalkylene oxide having a melt viscosity of 400,000 poise or more is used, the compatibility with a thermoplastic resin is not sufficiently improved, and the water-absorbent resin in which the water-absorbent resin is uniformly dispersed is insufficient. The composition is difficult to obtain. Such a phenomenon remarkably appears when a thermoplastic resin having a low processing temperature such as low density polyethylene is used.

[0009]

The object of the present invention is to improve the dispersibility of a water-absorbent resin, and when it is used alone or in combination with other general-purpose resins to form a film, sheet, fiber or the like, the processability is improved. The object is to provide a water-absorbent resin composition which is excellent in strength and has excellent physical properties such as tensile strength and elongation, as well as hydrophilicity and water absorbency.

[0010]

In view of the above situation, the present inventors have made extensive studies to solve the above problems. As a result, by using a cross-linked polyalkylene oxide having a specific melt viscosity as the water-absorbent resin and adding a copolymer of ethylene and a carboxyl group-containing monomer as the third component, the dispersibility in the thermoplastic resin is dramatically increased. It has been found that a water-absorbent resin composition in which these components are uniformly dispersed can be obtained, and the present invention has been completed.

That is, the gist of the present invention is that when a water absorbent resin composition is constituted, a melt viscosity at 170 ° C. and a load of 50 kg / cm ² obtained by reacting a polyalkylene oxide and an active hydrogen-containing compound with an isocyanate compound. 100 parts by weight of a polyalkylene oxide-modified product as a water absorbent resin having a porosity of 5000 to 1,000,000 poises,
10 to 5000 parts by weight of a thermoplastic resin and 1 to 100 parts by weight of a copolymer of ethylene and a carboxyl group-containing monomer are used.

The water absorbent resin used in the present invention is a polyalkylene oxide-modified product obtained by reacting a polyalkylene oxide and an active hydrogen-containing compound with an isocyanate compound. As the polyalkylene oxide, those having a weight average molecular weight of 1,000 to 1,000,000 are used, and examples thereof include polyethylene oxide, polypropylene oxide, ethylene oxide-propylene oxide copolymer,
Examples thereof include polybutylene oxide and a mixture thereof. In particular, polyethylene oxide, polypropylene oxide, a mixture thereof or a copolymer thereof having a weight average molecular weight of 2000 to 100,000 is preferable.

When the weight average molecular weight of the above-mentioned polyalkylene oxide is less than 1000, the water absorption property of the resulting polyalkylene oxide modified product is extremely lowered or the melt viscosity is extremely increased, resulting in a water absorbent resin composition. If the processing temperature for molding is not high, the dispersibility may be deteriorated, which is not preferable. On the other hand, when the weight average molecular weight of the polyalkylene oxide exceeds 1,000,000, the crosslinked density of the obtained polyalkylene oxide modified product becomes low and sufficient water absorption cannot be obtained, or the water absorbent resin composition is molded. When it is set to “1”, the gel is eluted on the surface during water absorption and the surface condition is deteriorated, which is not preferable.

Examples of the active hydrogen-containing compound include water, polyols, amines, carboxylic acids and the like. As the polyols, organic compounds having two or more hydroxyl groups (-OH) in the same molecule, for example, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, trimethylene glycol, 1, 3-butanediol, 2,3-butanediol, 1,4-butanediol, 1,5-pentanediol, hexylene glycol, octylene glycol,
Examples thereof include glyceryl monoacetate, glyceryl monobutyrate, 1,6-hexanediol, 1,9-nonanediol, bisphenol A and glycerin. Preferably, ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, 1,9-nonanediol or the like is used.

As the amines, compounds having two or more amino groups (-NH ₂ ) in the same molecule, for example, ethylenediamine, 1,4-diaminobutane, 1,3-diaminopropane, 1,5-diaminopentane. , Propylenediamine, 2,4-diaminotoluene, 2,6-diaminotoluene and the like. Preferably 1,4
-Diaminobutane and 1,3-diaminobutane are used.

As the carboxylic acids, compounds having two or more carboxyl groups (-COOH) in the same molecule, such as adipic acid, oxalic acid, malonic acid, glutaric acid,
Succinic acid, pimelic acid, azelaic acid and the like are used.
Preferably, adipic acid, glutaric acid, pimelic acid, azelaic acid and the like are used. These active hydrogen-containing compounds may be used alone or in combination.

The active hydrogen-containing compound is usually added at the time of reaction between the polyalkylene oxide and the isocyanate compound, but may be added at the end of the reaction. By adding the active hydrogen-containing compound, the melt viscosity of the obtained polyalkylene oxide-modified product can be reduced, and the processability is improved.

The isocyanate compound used to crosslink the above polyalkylene oxide and the above active hydrogen-containing compound is an isocyanate group (--NC) in the same molecule.
O) one or more organic compounds, for example, n
-Propyl isocyanate, n-butyl isocyanate, n-hexyl isocyanate, dodecyl isocyanate, cyclohexyl isocyanate, benzyl isocyanate, phenyl isocyanate, 4,4'-diphenylmethane diisocyanate (MDI), hexamethylene diisocyanate, 1,8-dimethylbenzol-
Reaction of 2,4-diisocyanate, 2,4-tolylene diisocyanate (TDI), TDI trimer, polymethylene polyphenyl isocyanate, trimethylol propane and other polyols with a number of moles of diisocyanate corresponding to the number of active hydrogens. Examples thereof include urethane isocyanate compounds and polyisocyanate adducts. Preferably, 4,4'-diphenylmethane diisocyanate (MDI), hexamethylene diisocyanate, 2,4-tolylene diisocyanate (TD)
I) or the like is used.

The proportions of the polyalkylene oxide, the active hydrogen-containing compound and the isocyanate compound used are the ratio of the sum of the number of active hydrogens of the terminal hydroxyl group of the polyalkylene oxide and the active hydrogen-containing compound and the number of isocyanate groups of the isocyanate compound ( R value) (-NCO group / H)
Is in the range of 0.5 to 3.0, preferably 0.8 to
A range of 2.5 is preferable. If the R value is less than 0.5,
The crosslink density becomes low and a water-absorbent resin having sufficient water absorbency cannot be obtained. On the other hand, if the R value exceeds 3.0, the crosslink density becomes high and the melt viscosity becomes high, so that the workability during molding is deteriorated, which is not preferable. The number of moles of the above polyalkylene oxide can be determined by dividing the weight by the average molecular weight.

The amount of the isocyanate compound used varies depending on the type of the isocyanate compound and conditions such as reaction, but is generally 0.5 to 80 parts by weight, preferably 1 to 100 parts by weight of the polyalkylene oxide. ~ 50
The range is parts by weight. If the amount is less than 1 part by weight, the crosslinked density of the obtained polyalkylene oxide-modified product is low and sufficient gel strength cannot be obtained. On the other hand, when it exceeds 80 parts by weight, the melt viscosity of the obtained polyalkylene oxide modified product becomes too high, and the processing temperature at the time of molding the above polyalkylene oxide modified product or a composition containing the same into a film or sheet. Is high, the molding becomes difficult, and the dispersibility becomes poor, which is not preferable.

As a method for reacting a polyalkylene oxide and an active hydrogen-containing compound with an isocyanate compound, a method of reacting in a solution using a suitable solvent is generally used, but a method of reacting in a dispersed state, a powder form or It is also possible to use a method in which both are uniformly mixed in a solid state and then heated to a predetermined temperature to cause a reaction.

The reaction temperature for the above reaction is usually 50 to 150.
℃. The reaction can be promoted by adding a small amount of triethylamine, triethanolamine, dibutyltin laurate, dibutyltin acetate, triethylenediamine or the like to this reaction system. By reacting a polyalkylene oxide and an active hydrogen-containing compound with an isocyanate compound, a temperature of 170 ° C., 5
Melt viscosity under load of 0 kg / cm ² is 5000 to 10
It is possible to obtain a polyalkylene oxide-modified product having a poise of 100,000.

The melt viscosity is a measure of the compatibility with the thermoplastic resin. When the melt viscosity of the polyalkylene oxide-modified product is less than 5000 poise, when the water absorbent resin composition is molded, the gel elutes on the surface during water absorption and the surface condition deteriorates. On the other hand, when the melt viscosity of the polyalkylene oxide-modified product exceeds 1,000,000 poise, the compatibility with the thermoplastic resin decreases, and it is not preferable because a uniformly dispersed water-absorbent resin composition cannot be obtained. Temperature 170 ℃, 50kg /
A modified polyalkylene oxide having a melt viscosity of 5,000 to 1,000,000 poise under cm ² loading was used.
By adding a copolymer of ethylene and a carboxyl group-containing monomer as a component, compatibility with a thermoplastic resin is good, and a water absorbent resin composition in which these components are uniformly dispersed can be obtained.

The thermoplastic resin used in the present invention is not particularly limited, and ordinary resins such as polyolefin resin, polyamide resin and polyester resin are used. You may use these thermoplastic resins individually or in mixture of 2 or more types as appropriate.

Examples of the above-mentioned polyolefin resin include polyethylene, polypropylene, polyvinyl chloride,
Other vinyl group-containing homopolymers such as polyvinylidene chloride, polyvinyl acetate, polyvinyl acetal, polystyrene, polyacrylic acid ester, polymethacrylic acid ester, acrylonitrile, styrene-butadiene copolymer, acrylic rubber-acrylonitrile-styrene terpolymer, Acrylonitrile-styrene-butadiene copolymer, chlorinated polyethylene-acrylonitrile-styrene graft polymer, chlorosulfonated polyethylene,
Examples thereof include acrylonitrile-ethylene-ethylene propylene rubber terpolymer. Preferably, polyethylene, polypropylene, polyvinyl chloride, acrylonitrile-styrene-butadiene copolymer, chlorosulfonated polyethylene and the like are used.

The polyamide resin is, for example, 6
-Nylon, 6,6-Nylon, 6,10-Nylon,
Examples include 11-nylon and 12-nylon. Examples of the polyester resin include polyethylene terephthalate and polybutylene terephthalate.

In the present invention, as described above, a copolymer of ethylene and a carboxyl group-containing monomer is added as the third component in order to improve the compatibility between the water absorbent resin and the thermoplastic resin. The carboxyl group-containing monomer is not only a monomer having a COOH group,
It also includes salts and ester forms thereof. Examples of the copolymer of ethylene and a carboxyl group-containing monomer include ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer and partially neutralized products thereof, ethylene-ethyl acrylate-maleic anhydride copolymer. Examples thereof include a polymer, an ethylene-maleic anhydride copolymer, an ethylene-ethyl acrylate copolymer, an ethylene-methyl methacrylate copolymer, and an ethylene-vinyl acetate copolymer.

Among them, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer and the like-
A copolymer with a COOH group-containing monomer is preferably used. Particularly, the content of the COOH group-containing monomer is 1 to 25
The above-mentioned ethylene-acrylic acid copolymer and ethylene-methacrylic acid copolymer, which are in weight%, are more preferably used.

It is not clear why excellent effects can be obtained by adding the above-mentioned copolymer of ethylene and a carbonyl group-containing monomer (hereinafter referred to as "ethylene copolymer"), particularly COOH group-containing ethylene copolymer. However, the oxygen atom in the modified polyalkylene oxide, which is a water-absorbent resin, is hydrogen-bonded to the COOH group in the ethylene copolymer containing a COOH group, so that the compatibility with the thermoplastic resin is improved. It is supposed to be improved.

The mixing ratio of the thermoplastic resin, the polyalkylene oxide-modified product and the ethylene copolymer is 10 to 5000 parts by weight, preferably 50 to 4000 parts by weight, based on 100 parts by weight of the polyalkylene oxide-modified product. Parts, and the ethylene copolymer is 1 to 100 parts by weight, preferably 2 to 50 parts by weight.

When the amount of the above-mentioned thermoplastic resin is less than 10 parts by weight, when the resulting water-absorbing part by weight composition is molded and allowed to absorb water, the water-absorbing gel is released from the thermoplastic resin and is eluted on the surface to deteriorate the surface condition. Therefore, it is not preferable. On the other hand, when the amount of the above-mentioned thermoplastic resin exceeds 5,000 parts by weight, the hydrophilicity and antistatic effect of the molded product cannot be sufficiently observed, which is not preferable.

When the amount of the ethylene copolymer is less than 1 part by weight, the effect as a compatibilizing agent between the thermoplastic resin and the polyalkylene oxide modified product is small, the dispersibility of the polyalkylene oxide modified product is poor, and the strength properties are low. The decrease is also large, which is not preferable. On the other hand, even if the ethylene copolymer exceeds 100 parts by weight, an effect commensurate with it cannot be obtained, which is not a good idea.

In order to obtain the water absorbent resin composition of the present invention by mixing the thermoplastic resin, the polyalkylene oxide modified product and the ethylene copolymer, a melt mixing means such as an ordinary kneader, Banbury mixer or extruder is used. To be If desired, the water absorbent resin composition of the present invention may contain additives such as a plasticizer, a stabilizer, a filler, a pigment, a vulcanizing agent and a vulcanization accelerator.

Regarding the method of adding the ethylene copolymer, the three components of the ethylene copolymer, the thermoplastic resin and the polyalkylene oxide modified product are dry blended and then melt-mixed at the same time, or the ethylene copolymer is previously mixed. It is also possible to melt-blend the polyalkylene oxide-modified product or the ethylene copolymer and the thermoplastic resin, and then add and mix the remaining components.

The water-absorbent resin composition of the present invention can be used in various forms by itself, but it can also be used as a compound (masterbatch) and blended with other general-purpose resins.

[0036]

EXAMPLES The present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

The melt viscosity of the polyalkylene oxide-modified product obtained in the examples, the appearance of the water-absorbing composition containing the polyalkylene oxide-modified product, and the evaluation of the molded product obtained by molding the composition Was performed according to the following method.

Evaluation of Polyalkylene Oxide Modified Product (Measurement of Melt Viscosity) As a measurement sample, 1.5 g of a polyalkylene oxide modified product was used, and a flow tester (CFT) was used.
-500C, manufactured by Shimadzu Corporation) under the following conditions. Weighted 50 kg / cm ² Measurement temperature 170 ° C. Die diameter 1 mm Die length 1 mm (Evaluation of appearance) Kneading roll or extruder of polyalkylene oxide modified product, thermoplastic resin and ethylene copolymer,
Appearance of kneaded product when kneading with pressure kneader (tub,
(Coloring, etc.) was evaluated according to the following criteria. ◯: No bumps, no coloration Δ: Some bumps are observed X: Large amount of bumps (Molded product evaluation method) The following method was used to evaluate a molded product or processed product obtained by adding the water-absorbent resin composition. Went according to. (1) Evaluation of dispersibility A water-absorbent resin composition was formed into a sheet having a thickness of about 2 mm by hot pressing, and the surface state of the sheet was observed with the naked eye and an electron microscope (100).
And the dispersibility was evaluated. The evaluation criteria are as follows. ◯: The observation with the naked eye is good, and no particles are observed even when observed with an electron microscope. Δ: The observation with the naked eye is good, but particles are observed with an electron microscope. X: Grainy particles are observed when observed with the naked eye. (2) Water Absorption Test After molding into a sheet of 20 × 40 × 0.5 mm, the sheet was immersed in pure water for 24 hours. The water absorption amount at that time was measured, the water absorption rate was calculated by the following formula, and the water absorption state of the sheet was visually judged according to the following evaluation criteria. Water absorption rate (%) = (weight after water absorption (g) -weight before water absorption (g)) / (weight before water absorption (g)) × 100 Water absorption state ◯: Good surface condition, no gel desorption, and no slimy feeling. Δ: The surface condition is good, but there is a slimy feel. X: The gel was detached to the surface, and the slimy feeling was large. (3) Tensile strength and elongation Measured according to JIS K7113.

Example 1 A 1-liter four-necked separable flask equipped with a condenser, a nitrogen inlet tube, a thermometer and a stirrer had a weight average molecular weight of 20.
000 polyethylene oxide 100g, toluene 55
After charging 0 ml, the water was removed by distillation to remove water.
ml of toluene was distilled off. 3.04 g of 4,4'-diphenylmethane diisocyanate, 0.54 g of 1,4-butanediol and 0.02 of triethylenediamine.
3 g was added and the reaction was carried out at 110 ° C. for 3 hours. Then, add 175 ml of hexane, cool to room temperature,
The polymer was precipitated. This slurry was filtered under pressure and dried under reduced pressure to obtain 100 g of a polyethylene oxide-modified product having a melt viscosity of 100,000 poise at a temperature of 170 ° C. and a load of 50 kg / cm ² . 100 parts by weight of the obtained polyethylene oxide-modified product was added to low-density polyethylene (Sumikasen F2
08-3, MI = 1.5, manufactured by Sumitomo Chemical Co., Ltd.) 100 parts by weight, as a third component, an ethylene acrylic acid copolymer (Yukaron A220M, AA = 8.5%, MI = 7, manufactured by Mitsubishi Petrochemical Co., Ltd.) ) After dry blending 10 parts by weight with a Henschel mixer, kneading with a 30 m / m extruder (170 ° C.),
After pelletization, a press sheet was prepared and the performance was evaluated. The obtained pellets were subjected to inflation molding with an extruder (150 ° C.) of 30 m / m, but there was no mesiness (dust accumulated around the inflation die) or bleeding phenomenon, and a film with a good surface condition (50 μm) was gotten.

Example 2 Polyethylene oxide 10 having a weight average molecular weight of 20,000
0 g, 4,4'-diphenylmethane diisocyanate 2.49 g as a cross-linking agent, 1,6-
100 g of a polyethylene oxide-modified product having a melt viscosity of 50,000 poises at a temperature of 170 ° C. and a load of 50 kg / cm ² was performed in the same manner as in Example 1 except that 0.65 g of hexanediol was used and 0.023 g of triethylenediamine was added.
Got 100 parts by weight of the obtained polyethylene oxide modified product was added to high-density polyethylene (J110K, MI = 19,
1000 parts by weight of Idemitsu Petrochemical Co., Ltd. and ethylene acrylic acid copolymer (Primacol 5980, A as the third component)
After blending 20 parts by weight of A = 20%, MI = 300, manufactured by Dow Chemical Co., Ltd. with a mixer, a 4-inch roll (17
After kneading at 0 ° C. for 15 minutes), a press sheet was prepared and the performance was evaluated.

Example 3 As a polyalkylene oxide, a weight average molecular weight of 850
Polyethylene oxide of 0, 2,4 as a cross-linking agent
- using tolylene diisocyanate 9.2 g, using 1,9 2.82g diol, except that triethylamine was added 0.31g in the same manner as in Example 1, temperature 170 ℃, 50kg / cm ² weight As a result, 100 g of a polyethylene oxide-modified product having a melt viscosity of 200,000 poise was obtained. 100 parts by weight of the obtained polyethylene oxide modified product and 5 parts by weight of an ethylene methacrylic acid copolymer (Nucrel N2060, MA = 20%, MI = 60, manufactured by Mitsui DuPont Polychemical Co., Ltd.) were kneaded with a pressure kneader (150 ° C. × 150 ° C.). After 15 minutes), 500 parts by weight of polypropylene (Nobrene Y101, MI = 12, manufactured by Sumitomo Chemical Co., Ltd.) was added, and the mixture was kneaded at 200 ° C. for 15 minutes, and then a press sheet was prepared to evaluate the performance.

Example 4 As a polyalkylene oxide, a weight average molecular weight of 110
80 g of polyethylene oxide and weight average molecular weight of 4
2,000 polypropylene oxide 20g, hexamethylene diisocyanate 7.27g as a cross-linking agent, 1,4-butanediol 0.98g as a diol
In the same manner as in Example 1, except that
100 g of a modified polyalkylene oxide having a melt viscosity of 400,000 poise under a load of 50 kg / cm ² was obtained. 100 parts by weight of the obtained modified polyalkylene oxide and 2000 parts by weight of an acrylonitrile-styrene-butadiene copolymer (Clarastic GA-501, manufactured by Sumitomo Dow Co., Ltd.)
As a component, 10 parts by weight of ethylene methacrylate copolymer (Himilan 1605, MI = 2.8, manufactured by Mitsui DuPont Polychemical Co., Ltd.) was dry blended with a Henschel mixer, and then kneaded with an extruder (200 ° C.) of 30 m / m, After pelletization, a press sheet was prepared and the performance was evaluated.

Example 5 100 g of polyethylene oxide having a weight average molecular weight of 100,000 was used as the polyalkylene oxide, and 4,4'-diphenylmethane diisocyanate 1.56 was used as the crosslinking agent.
g, and 1,9-nonanediol 0.24 g as the active hydrogen-containing compound, stanas octoate 0.1
Melt viscosity 8 in the same manner as in Example 1 except that g was added.
100 g of a polyethylene oxide-modified product of 50,000 poise was obtained. 100 parts by weight of the obtained polyethylene oxide modified product, 2 parts by weight of a stabilizer (Irganox 1010, manufactured by Ciba-Geigy) and polyethylene terephthalate (C1-
3000 parts by weight of TOBR, manufactured by Unitika Ltd., and ethylene acrylic acid copolymer (Primacol 132) as the third component.
0, AA = 6.5%, MI = 2.5, manufactured by Dow Chemical Co., Ltd.) 50 parts by weight were dry blended with a Henschel mixer, and then kneaded with a 30 m / m extruder (240 ° C.) and pelletized, followed by press sheeting. Was produced and the performance was evaluated.

Comparative Example 1 A press sheet was prepared in the same manner as in Example 1 except that the ethylene acrylic acid copolymer was not added when the polyethylene oxide-modified product and the low density polyethylene were kneaded. did. On the other hand, an inflation film was produced in the same manner as in Example 1. No blowout was found on the inflation die, but some bleeding was found on the film surface.

Comparative Example 2 Nylon 12 (Dyamide Nylon 1 was used instead of the ethylene acrylic acid copolymer when kneading the polyethylene oxide modified product and the low density polyethylene in Example 1.
2, manufactured by Daicel Co., Ltd.) A press sheet was prepared in the same manner except that 10 parts by weight was added, and the performance was evaluated. On the other hand, an inflation film was produced in the same manner as in Example 1.
Meaning was generated on the inflation die, and bleeding was observed on the surface of the film. Examples 1-5, Comparative Example 1
Table 1 shows the results of the evaluation of the workability, the dispersibility of the composition in the processed product, the water absorption state, and the like.

[0046]

[Table 1]

[0047]

According to the present invention, a water absorbent resin composition in which a thermoplastic resin and a water absorbent resin are uniformly dispersed can be obtained. Molded products such as films and sheets obtained by molding the water-absorbent resin composition alone or as a blending component are excellent in strength properties such as tensile strength and elongation, and have hydrophilicity, water absorption, antistatic action and water absorption. The surface condition afterwards becomes excellent.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Naoyuki Hashimoto, 1 No. 1 Irifune-cho, Shikima-ku, Himeji-shi, Hyogo Sumitomo Seika Chemical Co., Ltd. 2nd research institute (72) Shuichi Kashishima No. 1 Irifune-cho, Shikima-ku, Himeji-shi, Hyogo Sumitomo Seika Chemical Co., Ltd. Second Research Center

Claims (3)

[Claims] 1. A melt viscosity at 170 ° C. and a load of 50 kg / cm ² obtained by reacting a polyalkylene oxide and an active hydrogen-containing compound with an isocyanate compound is 5.
From 100 parts by weight of a modified polyalkylene oxide as a water-absorbing resin having a pressure of 000 to 1,000,000 poise, 10 to 5000 parts by weight of a thermoplastic resin, and 1 to 100 parts by weight of a copolymer of ethylene and a carboxyl group-containing monomer. A water-absorbent resin composition comprising: 2. The water absorbent resin composition according to claim 1, wherein the copolymer of ethylene and a carboxyl group-containing monomer is an ethylene-acrylic acid copolymer or an ethylene-methacrylic acid copolymer. 3. The water absorbent resin composition according to claim 2, wherein the content of the carboxyl group-containing monomer in the copolymer of ethylene and the carboxyl group-containing monomer is 1 to 25% by weight.