JPH03162437A - Water absorbing polymer complex - Google Patents

Abstract

PURPOSE:To obtain a water absorbing polymer complex consisting of a modified elastomer obtained by adding an alpha,beta-unsaturated carboxylic acid anhydride to EPR and/or EPDM and water absorbing polymer containing COOH-reactive functional group and having excellent long-term stability. CONSTITUTION:The aimed water absorbing complex obtained by using (A) 0.5-99.5wt.% modified elastomer obtained by adding an alpha,beta-unsaturated carboxylic acid anhydride (preferably maleic anhydride) to ethylene-alpha-olefin copolymer (EPR) and/or ethylene-alpha-olefin-non-conjugated diene copolymer (EPDM) and (B) 99.5-0.5wt.% water absorbing polymer (e.g. acrylic acid-vinyl alcohol crosslinked body) as main components and reacting the component A with the component B, preferably under nitrogen atmosphere at 50-250 deg.C, preferably 70-120 deg.C, as necessary, in the presence of a dehydrating agent.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a novel water-absorbing polymer composite.

[Conventional technology] There has been a strong demand for water-absorbing properties to be imparted to hydrophobic materials such as Gokai rubber and Gokai resin, and water-swellable sealants made by mixing water-absorbing polymers with soft resins and rubbers have been developed. Many materials are known.

However, in the conventional method, the strength decreases due to imparting water-swellability, and the balance between mechanical strength and swelling property is poor, and the results are not satisfactory.

Additionally, in areas where weather resistance is required, sealants using diene elastomers such as natural rubber lose their rubber elasticity after swelling with water, resulting in poor shape retention, poor sealing performance, and poor long-term stability. There is a demand for a sealant with a certain

[Problems to be Solved by the Invention] The present invention has been made against the background of the above-mentioned problems of the prior art, and has a structure in which the water-absorbing polymer does not desorb even after long-term use, and has a balance between mechanical strength and swelling rate. is good, and has good heat resistance.
The purpose of the present invention is to provide a water-absorbing polymer composite with excellent weather resistance, ozone resistance, and water resistance.

[Means to solve the problem]

The present invention provides (a) an ethylene-α-olefin copolymer (
EPR) and/or ethylene-α olefin-nonconjugated diene copolymer (EPDM) modified elastomer with one or more α,β monounsaturated carboxylic acid anhydrides added from 0.5 to 99.5% by weight; The present invention provides a water-absorbing polymer composite mainly consisting of 99.5 to 0.5% by weight of a water-absorbing polymer containing a functional group capable of reacting with a carboxyl group.

(a) The modified elastomer used in the present invention is EPR
and/or obtained by adding α,β monounsaturated carboxylic acid anhydride to EPDM.

Here, EPR is abbreviated as propylene is the most representative and important α-olefin, but there are also 1 other α-olefins.
-butene, l-hexene, 1-decene, 4-methyl-1
-pentene, -heptene, 4-methyl-1-hexene, etc. are exemplified.

Furthermore, EPDM is obtained by copolymerizing the monomers constituting the EPR with a non-conjugated diene added, and the non-conjugated diene includes 1. Examples include 4-hexadiene, dicyclopentadiene, and ethylidenenorbolone.

Here, the weight ratio of ethylene:α-olefin is 90:
10-20:8, preferably 85:15-40:60,
More preferably, the ratio is 75:25 to 45:55.

In addition, the non-conjugated diene has an iodine value of O~ in the case of EPR.
50, and generally 5 to 35 for EPDM.

In addition, the Mooney viscosity of EPR and/or EPDM (
MLI-4, 100″C) is preferably 10~
350, more preferably 15-80.

α to be added to this EPR and/or EPDM. β
Examples of monounsaturated carboxylic anhydrides include maleic anhydride, itaconic anhydride, methyl maleic anhydride, phenyl maleic anhydride, citraconic anhydride, and the like.
Maleic anhydride is particularly preferred. These α. The β-unsaturated carboxylic acid anhydrides can be used alone or in combination of two or more.

This (a) method for producing a modified elastomer involves kneading EPR and/or EPDM and an α,β monounsaturated carboxylic acid anhydride at a temperature of 150 to 300°C using a Banbury mixer, a kneader blender, or the like. It can be obtained by heat treatment using a machine, a continuous kneader, or an extruder.

In this case, some organic peroxide may be used in combination.

More specifically, the method for producing the modified elastomer (a) is as follows: EPR is mixed with maleic anhydride and an organic peroxide, and then kneaded in an extruder to produce modified EP.
Method for obtaining R (Japanese Patent Publication No. 59-13537), EP
A method for producing modified EPDM by mixing DM with maleic anhydride and 2,2'-benzothiazyl sulfide (MBTS) in a Banbury mixer (A, Y. Cor.
An, Rubbercorn '87, or US Pat. No. 4,410,656).

The amount of these α,β monounsaturated carboxylic acid anhydrides added to EPR and/or EPDM is preferably 0.05 to 10 parts by weight, more preferably 0.1 to 5 parts by weight, per 100 parts by weight of the latter. , is particularly preferably 0.2 to 3 parts by weight; if it is less than 0.05 parts by weight, the compatibility with the water-absorbing polymer (orally) becomes poor and the desired result cannot be obtained;
If it exceeds 0 parts by weight, the mechanical strength will decrease due to gelation,
Workability also deteriorates.

The melt viscosity of the modified elastomer (a) used in the present invention is 0.05 to 15, preferably 0.1 to 10 in terms of melt flow rate (g/10 minutes, 230°C).

Next, (b) the water-absorbing polymer has a functional group that can react with a carboxyl group, and the functional group includes, for example, a hydroxyl group, an amino group, an ado group, and preferably a hydroxyl group. can.

Specific examples of the second (oral) water-absorbing polymer include acrylic acid monovinyl alcohol crosslinked product; polyvinyl alcohol;
Commercially available water-absorbing polymers include crosslinked polyols made by randomly adding ethylene oxide and propylene oxide to polyhydric alcohols.

(b) As a water-absorbing polymer, a water-soluble vinyl heptanomer having a functional group capable of reacting with a carboxyl group, such as a hydroxyl group, and another water-soluble vinyl heptanomer may be (co)polymerized in combination. The water-absorbing polymer can be obtained by the following steps. Examples of the water-soluble vinyl monomers having a hydroxyl group include hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, polyethylene glycol mono (meth)acrylate, polyprobyl glycol mono (meth)acrylate,
-Hydroxyethyl (meth)acrylamide etc. 20
It may be used in a proportion of mol % or more, and may also be copolymerized with (a) anionic, (b) nonionic, or (C) cationic vinyl monomer.

Among these, (a) anionic vinyl heptanomers include acrylic acid, methacrylic acid, itaconic acid, maleic acid, crotonic acid, sorbic acid, fumaric acid, and cinnamic acid, which are water-soluble vinyl monomers having a carboxyl group. etc. as a water-soluble hinyl monomer having a sulfone group,
Vinyl sulfonic acid, vinyltoluene sulfonic acid, styrene sulfonic acid, 2-acrylate ξ-2-methylpropanesulfonic acid, 2-(meth)acryloylethanesulfonic acid, sulfoethyl (meth)acrylate, sulfopyl (meth)acrylate , 2-methyl-1. Examples of water-soluble vinyl monomers having a phosphonic group include 3-butadiene-1-sulfonic acid, vinylphosphonic acid, and 2-acrylamido-2-methylpropanephosphonic acid.

These (a) anionic vinyl heptanomers are usually
It is used after neutralizing 60 to 80 mol% of the anionic vinyl monomer using sodium hydroxide or potassium hydroxide. These anionic vinyl heptanomers (a) can be used alone or in combination of two or more.

In addition, (6) nonionic vinyl monomers include vinylpyrrolidone, (meth)acrylamide, N,N'-
Dimethyl (meth)acrylamide, dimethylaminopropyl (meth)acrylamide, dimethylaminoethyl (
Examples include meth)acrylate, diethylacetyl(meth)acrylate, dimethylaminopropyl(meth)acrylate, 2-vinylpyridine, and 4-vinylpyridine. These (b) nonionic vinyl monomers can be used alone or in combination of two or more.

Furthermore, as the (C) cationic vinyl monomer,
(meth)acryloyloxyethyltrimethylammonium chloride, (meth)acryloyloxyethyltrimethylammonium bromide, (meth)acryloyloxyhydroxyethyltrimethylammonium chloride, (meth)acryloyloxyhydroxyethyltrimethylammonium bromide, trimethylaminoethyl (meth)acrylamide. chloride or bromide,
Examples include trinotylallylammonium chloride and trinotylallylammonium buchamide. These cationic vinyl monomers (C) can be used alone or in combination of two or more.

Furthermore, in the present invention, another heptanomer having two or more unsaturated bonds in the molecule, exhibiting a certain degree of water solubility, and copolymerizable with the water-soluble vinyl monomer is used. Can be used with Nomer. As this monomer, a polyfunctional monomer is preferable because it has an effect as a crosslinking agent.

Examples of the monomer as this crosslinking agent include N, N'
- Examples include methylene bisacrylamide, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, and glycerin tri(meth)acrylate, used alone or in combination of two or more. be able to.

The amount of these crosslinking agents used is usually 0.05 to 5% by weight, preferably 0.1% by weight based on the water-soluble vinyl monomer.
-2% by weight, and if it is less than 0.05% by weight, some water-soluble polymers will be formed, resulting in a gel with unstable water absorption capacity, while if it exceeds 5% by weight, the water absorption capacity will be too small to be practical.

In addition, a compound having 2 or more functional groups that can react with a water-soluble vinyl monomer or a water-absorbing polymer (hereinafter referred to as a "crosslinkable compound") is used as a type of crosslinking agent for a water-soluble vinyl monomer. may coexist. In this case, the crosslinking reaction progresses after or during the polymerization of the water-soluble vinyl monomer, resulting in formal crosslinking.

Such crosslinkable compounds include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin triglycidyl ether,
Examples include shrimp chlorohydrin, α-methylchlorohydrin, glutaraldehyde, glyoxal, glycerin, pentaerythritol, ethylene glycol, and ethylene diamine.

The (oral) water-absorbing polymer used in the present invention can be polymerized using a water-soluble polymerization initiator.

Examples of the water-soluble polymerization initiator include hydrogen peroxide, ammonium persulfate, potassium persulfate, 2,2'-azobis(2
-amidinopropane) dihydrochloride, t-butyl hydroperoxide, and the like. These water-soluble polymerization initiators may be combined with reducing substances such as sodium bisulfite, ferrous sulfate, and triethanolamine to form a rednox type initiator.

The amount of this water-soluble polymerization initiator to be used is usually 0.00 to 0.0000000000000000000000000 with respect to the water-soluble vinyl monomer. Ol to 5% by weight, preferably 0.1 to 2% by weight, and 0.1 to 2% by weight. If the amount of Ol is less than 5% by weight, the polymerization reaction of the water-soluble vinyl monomer cannot be carried out efficiently, while if it exceeds 5% by weight, there will be some polymerization initiator remaining without being decomposed, and radicals will be gradually generated, resulting in water absorption. It has a negative effect on the polymer. (Example) The polymerization method for obtaining the water-absorbing polymer may be either an aqueous solution polymerization method or a reversed-phase suspension polymerization method, and preferably a reversed-phase suspension polymerization method.

At this time, the polymerization temperature in these polymerization methods is usually
30-11O°C, preferably 50-8o°C,
Polymerization time is usually 0.5 to 5 hours, preferably 1 to 3 hours.
It's time.

The preferred polymerization method, reversed-phase suspension polymerization, will be described in detail below. Hydrocarbon solvents used for reversed-sheath suspension polymerization include toluene, xylene, cyclohexane, hexane, heptane, methylcyclohexane, octane, decalin, etc. However, it is not limited to these as long as it does not inhibit the polymerization of the water-soluble vinyl monomer.

Furthermore, as the surfactant used in this reverse phase suspension polymerization method, a water-in-oil type surfactant is generally used.

Examples of the surfactant include sorbitan sesquioleate, sorbitan monooleate,
Examples include propylene glycol monolaurate, sorbitan monostearate, diethylene glycol monostearate, ethyl cellulose, benzyl cellulose, cellulose acetate, cellulose butyrate, maleated polyptadiene, maleated polyethylene, maleated α-olefin, etc. Used alone or in combination of two or more.

The amount of this surfactant used is usually 0.1 to 30% by weight, preferably 1 to 2% by weight, based on the water-soluble vinyl heptanomer.
It is about 0% by weight.

Next, under sufficient nitrogen substitution, the system was heated to 50 to 2,0
Stir and suspend at OO rpm, preferably 100-500 rpm.

This suspension is heated to a predetermined temperature to polymerize the water-soluble vinyl heptanomer.

After the polymerization is complete, when stirring is stopped, the swollen polymer particles settle, a swollen polymer is obtained by decanting, and a water-absorbing polymer is obtained by vacuum drying or hot air drying.

The obtained water-absorbing polymer can be used by pulverizing it with a freeze vibration ξ wheel.

(b) The particle size of the water-absorbing polymer obtained in this way is preferably 20 μm or less, more preferably 1 Oum.
If it exceeds 20 μm, not only will the mechanical strength of the resulting water-absorbing polymer composite significantly decrease, but it will not swell uniformly with water.

The water-absorbing polymer composite of the present invention mainly contains the above-mentioned (a) modified elastomer and (a) water-absorbing polymer,
These components (a) to (b) can be obtained by reacting preferably in a nitrogen atmosphere at 50 to 250°C, more preferably 70 to 120°C.

In this reaction, a dehydrating agent such as N,N'-dihexylcarbodiimide can be used in combination.

The usage ratio (weight ratio) of (a) modified elastomer and (b) water-absorbing polymer is (a)/(b)=99.5/0.
5-0.5/99.5, preferably 95/5-5/99
, particularly preferably from 85/l5 to 15/85, particularly from 80/20 to 20/80; (a) If the modified elastomer is less than 0.5% by weight, the bond between the modified elastomer and the water-absorbing resin is impaired. If the amount exceeds 99% by weight, the composition will not swell sufficiently in water due to its weak mechanical strength.

The water-absorbing polymer composite of the present invention can be used alone, but by blending it with various elastomers in an appropriate ratio, it can be used as an elastomer composite that has excellent performance as a water-absorbing or hydrophilic elastic body. It can also be used as an object.

Furthermore, by appropriately blending the water-absorbing polymer composite of the present invention with a composite resin such as a thermoplastic resin or a thermosetting resin, a resin having excellent water-absorbing properties or hydrophilic properties can be obtained.

Among these, the elastomer is natural rubber (NR
) Diene-based rubbers such as S-polyisoprene rubber (IR), styrene-butadiene rubber (SBR), polybutadiene rubber (BR), acrylonitrile-butadiene rubber (NBR), chloroprene rubber (CR), and butyl rubber (IIR); ethylene-propylene rubber (EPR),
Examples include non-diene synthetic rubbers such as ethylene-propylene-diene rubber (EPDM), acrylic rubbers (ACM, ANM), and fluororubbers, preferably NR, IR,
SBRSBR, NBR. ．． CR, I IR, EPR, E
It is PDM.

In addition to the various natural rubbers and synthetic rubbers mentioned above, examples of elastomers include syndiotactic 1,2-polybutadiene, trans-1,4-polyisobrene, trans-1,4-polybutadiene, ethylene-vinyl acetate copolymer, aromatic Hyny-conjugated diene block copolymer and its hydride; styrene-grafted ethylene-propylene elastomer, styrene-butadiene-styrene 1
・Librot ivy copolymer and its hydride, styrene-isoprene-styrene triblock copolymer and its hydride; Examples include thermoplastic polyester elastomer, thermoplastic polyamide elastomer, vinyl chloride elastomer, ethylene ionomer resin, etc., and preferred are syndiotactic 1,2-polybutadiene, styrene-butadiene block copolymer, styrene-butadiene-styrene-triblock copolymer, styrene-isoprene-styrene triblock copolymer, and hydrogenated products thereof.

On the other hand, thermoplastic resins used as resins include polyethylene, polypropylene, polyvinyl chloride, polycarbonate, and polyethylene terephthalate (PET).
), polybutylene terephthalate (PBT), polyacetal, polyamide, epoxy resin, polyphenylene sulfide resin (PPS), polyether ether ketone, polyphenylene oxide resin (PPO), rubber-modified PPO, as well as styrene-maleimide resins. polymer,
Rubber-modified styrene-maleimide copolymer, polystyrene, polychlorostyrene, polyα-methylstyrene, styrene-acrylic nitrile copolymer, styrene-methyl methacrylate copolymer, styrene-maleic anhydride copolymer, styrene-α-methyl Examples thereof include styrenic resins such as styrene copolymer, styrene-α-methylstyrene-methyl methacrylate copolymer, styrene-α-methylstyrene-acrylic nitrile-methyl methacrylate copolymer, and rubber modified products thereof.

Further, examples of the thermosetting resin used as the composite resin include phenol resin, epoxy resin, urea resin, melamine resin, and prepolymers of these resins.

The mixing ratio of the water-absorbing polymer composite of the present invention and the elastomer and/or synthetic resin is not particularly limited and can be pretented in an appropriate ratio depending on the purpose, but the former/latter (weight ratio) is as follows: Usually 1/99 to 99/l, preferably 2/98 to 90/10, more preferably 5/95 to 95/20, particularly preferably 7/93 to 5
0/5 0.

In the present invention, as a method of blending the water-absorbing polymer composite with the elastomer and/or the elastomer resin, both can be added and kneaded simultaneously, or the additives can be mixed in advance with one component and the remaining You can also add the precepts.

Mixing is carried out using various extruders, Banbury mixer kneaders, rolls, etc. at a temperature of 80 to 250°C, preferably 1
It can be carried out by kneading at 00 to 200°C for 0.1 to 2 hours, preferably about 0.2 to 1 hour, and a preferred kneading method is an internal mixer such as a Banbury mixer or a kneader. This method uses

In addition, various commonly used compounding agents other than the above-mentioned elastomer and/or composite resin can be added to the water-absorbing polymer composite obtained by the present invention.

These compounding agents may be added during the process of producing the composition, or may be added after producing the Mi precept, if necessary.

That is, examples of reinforcing fillers and extenders include carbon black, fumed silica, wet silica, fine quartz powder, zinc white, basic magnesium carbonate, activated calcium carbonate, magnesium silicate, aluminum silicate,
Titanium dioxide, talc, mica powder, aluminum sulfate,
Clay, iron oxide, magnesium oxide, calcium oxide,
Magnesium hydroxide, calcium sulfate, barium sulfate,
Mention may be made of ashesto, glass fibers, organic reinforcing agents and organic fillers.

As resolution aids, higher fatty acids and their metal amine salts; as plasticizers, for example, dioctyl phthalate, dibutyl phthalate, jetyl phthalate, dimethyl phthalate, tricresyl phthalate, tricresyl phosphate, triethyl phosphate, tributyl phosphate. , tri-2-ethylhexyl phosphate, phthalic acid derivatives such as trimellitic acid, adipic acid derivatives such as dioctyl adipate, dioctyl azelaate, dioctyl sebacate, epoxy fatty acids; liquid rubbers include liquid polyptadiene; Rubber, liquid polyisoprene rubber, liquid NBR rubber, liquid butyl rubber, liquid acrylic rubber, liquid EP:rm. Softeners include, for example, lubricating oils, process oils, coal tar, castor oil, calcium stearate, polybutene; anti-aging agents include:
For example, phenylene diamines, phosphates, quinolines, cresols, phenols, dithiocarbamate metal salts; heat-resistant agents such as iron oxide, cerium oxide, potassium hydroxide, iron naphthenate, potassium naphthenate; others Colorants, ultraviolet absorbers, flame retardants, oil resistance improvers, foaming agents, scorch inhibitors, tackifiers, lubricants, etc. can be optionally added.

These compositions are mixed with crosslinking agents such as organic peroxides, crosslinking aids, polyol vulcanizing agents, vulcanization accelerators, and post-curing vulcanizing agents using ordinary kneading machines such as rolls and Banbury mixers. After adding and kneading, molding and vulcanization can be carried out under normal vulcanized rubber manufacturing conditions.

Examples of the organic peroxide include cumene hydroperoxide, isoprobylbenzene hydroperoxide, paramenthane hydroperoxide, and benzoyl peroxide.

Examples of crosslinking aids include the following compounds.

That is, ethylene glycol dimethacrylate, 1
, 3-butanediol dimethacrylate, 1,4-butanediol dimethacrylate, 1,6-hexanediol dimethacrylate, polyethylene glycol dimethacrylate, 1,4-butanediol diacrylate, 1,6-hexane diol diacrylate, 2
．． 2'-bis(4-methacrylic diethoxyphenyl)propane, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, divinylbenzene, N,N'-methylenebisacrylamide, P-quinone di These include oxime, p,p'-dibenzoylquinone dioxime, triazinedithiol, triallyl cyanurate, triallyl isocyanurate, bismaleimide, and the like.

The amount of this crosslinking aid added is about 0.1 to 10 parts by weight, preferably about 0.5 to 7 parts by weight, based on 10 parts by weight of the composition.

As the polyol vulcanizing agent, polyhydroxy aromatic compounds such as hydroquinone, bisphenol A, bisphenol AF, and salts thereof are preferably used. Furthermore, fluorine-containing aliphatic diols can also be used. The amount of these polyol vulcanizing agents added is
It is usually about 0.1 to 20 parts by weight, preferably about 1 to 10 parts by weight.

As the vulcanization accelerator, methyltrioctylammonium chloride, benzyltriethylammonium chloride,
Quaternary ammonium compounds such as tetrahexylammonium tetrafluoroborate; 8-methyl-1,8-
Quaternary ammonium compounds such as (5,4.0)-7-undecenyl chloride; Quaternary phosphonium compounds such as benzyltriphenylphosphonium chloride, trifluoromethylbenzyltrioctylphosphonium chloride, benzyltrioctylphosphonium bromide Compounds are preferred.

The amount of the vulcanization accelerator added is usually about 0.2 to 10 parts by weight per 00 parts by weight of the vulcanization accelerator.

Agon vulcanizing agents include various alkyl amines such as hexamethylene diamine, tetraethylene pentamine, and triethylene tetra Salts of fatty acids such as carbanoic acid and cinnarylidenic acid can be used. The amount of such adan vulcanizing agent added is usually 0.00 parts by weight per 100 parts by weight of the assemblage. 1
The amount is about 10 parts by weight, preferably about 0.5 to 5 parts by weight.

To vulcanize the composition, the composition is usually subjected to primary vulcanization at 80 to 200"C for several minutes to 3 hours under a pressure of 20 to 200 kg/cdl, and if necessary, at 80 to 200"C for 1 to 3 hours.
Secondary vulcanization is performed for 48 hours to form a crosslinked product.

As described above, the water-absorbing polymer composite obtained by the present invention can be used for soil water retention forests, agricultural and horticultural applications such as soil improvement materials, civil engineering applications such as sealing materials and packing materials, water-absorbent/hygroscopic sheet materials, and dew condensation prevention. It can be used for construction purposes such as wall materials, water-absorbing laminates, and sanitary products.

In addition, the composition of the present invention, which is a blend of the water-absorbing polymer composite with an elastomer and/or a synthetic resin, can increase the strength of the water-absorbing polymer composite, and can improve the hydrophilicity, water absorption, and oil resistance of the elastomer or synthetic resin. It can be used in a wide range of applications that take advantage of these properties.

〔Example〕

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples.

In addition, in the examples, % and parts are based on weight unless otherwise specified. In addition, various measurements in the Examples were performed using the following test methods.

Dokosaraida 1F! ．． Pour 11 of pure water or seawater (see Table 1) into a beaker, adjust to 20°C, and heat 2 CTIIX vertically x 2 horizontally.
A water-absorbing polymer composite or a composition thereof having a cm x thickness of 2M was immersed, the weight after immersion was weighed, and the water swelling rate was calculated according to the following formula.

(In the formula, W0 is the weight of the dry sample, and W is the weight of the sample after swelling with water.) Table 1 was based on JIS K6301.

100 using Sunshine Super Long Weather Meter (WEL-SUN-HC type) manufactured by M Shoes M Kosuga Test Instruments ■
After irradiating with ultraviolet light for an hour (63°C), a water swelling test was conducted.

Reference Examples 1 to 3 500 g of n-hexane and 5 g of sorbitan monostearate were added to a four-piece separable flask with a capacity of If, which was equipped with a stirrer, a reflux condenser, a dropping funnel, and a nitrogen gas introduction tube. After addition and dissolution, nitrogen gas was blown in to drive out dissolved oxygen, and the internal temperature was brought to 70°C in a nitrogen gas atmosphere.

Next, the aqueous solution shown in Table 2 was placed in a dropping funnel with a volume of 300 ml in advance, 0.2 g of ammonium persulfate was added, and the contents of the dropping funnel were added to the four-piece parallel flask. ,300rpm
Polymerization was carried out at 70°C for 2 hours while stirring.

When the stirring was stopped after the polymerization was completed, the swollen polymer particles settled to the bottom of the flask, and the swollen polymer was obtained by decantation.

This swollen polymer was dried under reduced pressure at 80''C, and a water-absorbing polymer powder having a particle size of 10 am or less was obtained using a vibration mill.

Table 2 *1) N,N'-methylenebisacrylamide *2)
Tea bag method *3) 2-hydroxyethyl acrylate *4) Acrylic acid *5) 2-hydroxyethyl methacrylate *6) 2-
Acrylamide 2-methylpropanesulfonic acid *7) Metaacryloyloxyethyltrimethylammonium chloride Example 1 Coran's method (^. Y. Coran, Rubbe
rcorn '87), JSR EP33 (
Made by Japan Gosho Rubber, EPDM, propylene content = 43%
, iodine value=26%) was modified with maleic anhydride.

The amount of maleic anhydride added to this modified EPDM is 0.6%
Met.

The modified EPDM and Sumikagel SP-520 (manufactured by Sumitomo Chemical Co., Ltd., acrylic acid monovinyl alcohol copolymer) were combined into a plasto ξ in a nitrogen atmosphere at 120°C for 10 minutes.
Dixie clay, carpon plack, process oil, zinc white, stearic acid, sorbitan monostearate, and polyethylene glycol shown in Table 3 were kneaded at 120"C, and then kneaded at 70"C. The vulcanization system shown in Table 3 was kneaded to obtain a blend m.

This mixed composite sole was rolled out into a sheet, and the sheet-like material was press-vulcanized at 170° C. for 10 minutes to obtain a sheet with a thickness of 2 m.

Table 4 shows the physical properties of the obtained press sheet.

As is clear from Table 4, the water-absorbing polymer composite of the present invention had excellent a-mechanical properties, no desorption of the water-absorbing polymer after water absorption, and a smooth surface.

Table 3 *l) Manufactured by Nippon Oil & Fats *2) Manufactured by Ouchi Shinko Chemical Industry *Example 2 Instead of Sumikagel SP-520 in Example 1,
A vulcanized sheet of a water-absorbing polymer composite was obtained using the same recipe as in Example 1, except that the water-absorbing polymer of Reference Example 1 was used.

Table 4 shows the physical properties of the obtained press sheet.

This water-absorbing polymer composite also had excellent mechanical strength, no desorption of the water-absorbing polymer after water absorption, and a smooth surface.

Comparative Example 1 A vulcanized sheet of a water-absorbing polymer composite was obtained using the same recipe as in Example 1, except that JSR EP33 was used instead of the maleic anhydride-modified EPDM in Example 1.

Table 4 shows the physical properties of the obtained press sheet.

It can be seen that compared to Examples 1 and 2, Comparative Example 1 has lower mechanical strength and poor long-term stability.

Table 4 Example 3 JSR EP912P (manufactured by Japan Synthetic Rubber, EPR,
7′ropyrene content=22%) was modified with maleic anhydride at 200° C. in an extruder. This modified EPR
The amount of maleic anhydride added was 1.0%.

The modified EPR and Gohsenol GH-17 (manufactured by Nippon Gokai Kagaku Kogyo ■, partially saponified polyvinyl alcohol) were
After kneading at 30°C for 10 minutes in a nitrogen atmosphere using a plastomill, compounding ingredients other than peroxide shown in Table 5 were added at 120°C, and then at 60°C diku ruber oxide was kneaded. A blended composition was obtained.

This mixture was rolled out into a sheet, and the sheet was press-vulcanized at 170°C for 10 minutes to obtain a sheet with a thickness of 2 m. Table 6 shows the physical properties of the obtained press sheet.

As is clear from Table 6, the water-absorbing polymer composite of the present invention had excellent mechanical properties, no desorption of the water-absorbing polymer after water absorption, and a smooth surface. Table 5 Comparative Example 2 A vulcanized sheet of a water-absorbing polymer composite was obtained using the same recipe as in Example 3, except that JSR EP912P was used instead of the maleic anhydride-modified EPR in Example 3.

Table 6 shows the physical properties of the obtained press sheet.

Compared to Example 3, Comparative Example 2 has poor compatibility with partially saponified polyvinyl alcohol, so as the immersion time in water progresses, the polyvinyl alcohol dissolves and the swelling rate decreases.
(Margin below) Table 6 Example 4 Instead of the modified EPDM used in Example 1, 20 parts of the modified EPR obtained in Example 3 and 80 parts of JSREP33,
and Sumikagel SP-520 as a water-absorbing polymer.
Except that the water-absorbing polymer of Reference Example 2 was used instead of
A vulcanized seam 1 of a water-absorbing polymer composite was obtained using the same formulation as in Example 1. Table 7 shows the physical properties of the obtained press sheet.

As is clear from Table 1, the water-absorbing polymer composite of the present invention has excellent mechanical properties, no desorption of the water-absorbing polymer after water absorption, and excellent long-term stability. Comparative Example 3 Instead of the elastomer used in Example 4, JSR
A vulcanized sheet of a water-absorbing polymer composite was obtained using the same recipe as in Example 4, except that 20 parts of EP912P and 80 parts of JSR EP33 were used.

Table 7 shows the physical properties of the obtained press sheet.

Compared to Example 4, Comparative Example 3 has lower mechanical strength and poor long-term stability.

Table 7 Example 5 In place of the modified EPDM used in Example 1, 50 parts of the modified EPDM of Example 1 and 50 parts of natural rubber were used, and in place of Sumiriki Gel SP520 as the water-absorbing polymer, the water-absorbing material of Reference Example 3 was used. A vulcanized sheet of a water-absorbing polymer composite was obtained using the same recipe as in Example 1, except that a water-absorbing polymer was used. Table 8 shows the physical properties of the obtained press sheet.

As is clear from Table 8, the water-absorbing polymer composite of the present invention has excellent mechanical properties, no desorption of the water-absorbing polymer after water absorption, and excellent long-term stability.

Comparative Example 4 Instead of the elastomer used in Example 5, JSR
A vulcanized sheet of a water-absorbing polymer composite was obtained using the same recipe as in Example 5, except that 50 parts of EP33 and 50 parts of natural rubber were used.

Table 8 shows the physical properties of the obtained press sheet.

Compared to Example 5, Comparative Example 4 had lower mechanical strength and poor long-term stability.

Table 8 [Effects of the Invention] In the water-absorbing polymer composite of the present invention, since the water-absorbing polymer is bonded to the elastomer and made compatibilized, there is no desorption of the water-absorbing polymer even after long-term use, and mechanical Good balance between strength and swelling rate.

Claims (1)

[Claims] (1) (a) Ethylene-α-olefin copolymer (EP
R) and/or ethylene-α-olefin-nonconjugated diene copolymer (EPDM) with one or more α,β-unsaturated carboxylic acid anhydrides added to the modified elastomer 0
．． 5 to 99.5% by weight, and (b) 99.5 to 0.5% by weight of a water-absorbing polymer containing a functional group capable of reacting with a carboxyl group.