JPH09111038A - Hydrophilic gel and moisture-absorbing or releasing material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a moisture-absorbing or releasing material excellent in handleability and in the moisture-absorbing or releasing property by using a hydrophilic gel excellent in the moisture-absorbing or releasing property, etc. SOLUTION: This hydrophilic gel comprises 1pt.wt. of a crosslinked polymer and 50-200 pts.wt. of a polyhydric alcohol absorbed in the crosslinked polymer. This moisture-absorbing or releasing material contains the hydrophilic gel. The crosslinked polymer is especially preferably a polymer containing a (meth) acrylate ester monomer in an amount of >=20wt.% and represented by the formula: CH2 =CR-CO-(X)n -Y [R is H or methyl group; X is a 2-4C oxyalkylene group in which the molar fraction of oxyethylene groups on the basis of the whole oxyalkylene groups is >=50%; Y is a 1-5C alkoxy group, a phenoxy group, or an oxyalkylphenyl group having one to three 1-9C alkyl groups as substituents; (n) is an integer of 3-100] in an amount of >=20wt.%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydrophilic gel having a property of absorbing and releasing water vapor, and a moisture absorbing / releasing material for water vapor using the hydrophilic gel.

[0002]

2. Description of the Related Art Conventionally, a material that absorbs / releases water vapor, that is, a so-called moisture absorbing / releasing material has been known. When the moisture absorbing / releasing material is brought into contact with air, for example, in response to a change in humidity,
Absorbs or releases water vapor in the air. Specifically, the moisture absorbing / releasing material absorbs water vapor to act as a dehumidifying agent when the humidity is high, and releases the water vapor to act as a humidifying agent when the humidity is low. Thereby, the moisture absorbing / releasing material can suppress a change in humidity.

It is generally known that polyhydric alcohols are excellent in the property of absorbing and releasing water vapor, that is, the moisture absorbing and releasing property. However, since the polyhydric alcohol is a liquid, when it is used as a moisture absorbing / releasing material, the handling property is very poor.

Therefore, for example, Japanese Patent Publication No. 7-16603 discloses a moisture absorbing / releasing material containing a hydrophilic gel obtained by integrating a water-insoluble polymer and a polyhydric alcohol which is a moisture absorbing / releasing organic compound. The material is disclosed. In general, hydrophilic gels are easier to handle than liquids such as polyhydric alcohols, and have better moisture absorption and desorption properties than solids such as calcium chloride, and are therefore particularly preferably used as moisture absorption and desorption materials. When the hydrophilic gel is used as a constituent material of the moisture absorbing / releasing material, it is often used by enclosing it in a breathable bag such as a nonwoven fabric.

[0005]

However, in the conventional moisture absorbing / releasing material, the amount of the polyhydric alcohol absorbed per 1 part by weight of the polymer is less than 50 parts by weight. Therefore, the moisture absorption / desorption property is insufficient.

Further, as a result of studies by the inventors, it has been found that the above-mentioned conventional moisture absorbing / releasing material does not completely absorb water and polyhydric alcohol and is partially liquefied after absorbing moisture. For example, when the moisture absorbing / releasing material absorbs moisture under the conditions of a temperature of 15 ° C. and a relative humidity of 98%, the liquid is released by centrifugation,
The ratio of the released liquid to the hydrophilic gel, that is, the liquefaction rate exceeds 5% by weight. Thus, when the liquefaction rate of the moisture absorptive and desorptive material increases, when the hydrophilic gel is put in a bag having air permeability and used as the moisture absorptive and desorptive material, the liquid released from the hydrophilic gel after moisture absorption, It has a problem that it exudes from the bag and wets the surroundings.

The present invention has been made in view of the above conventional problems, and an object thereof is to provide, for example, a hydrophilic gel excellent in moisture absorption and desorption. Another object is to provide a moisture absorbing / releasing material having excellent handleability and moisture absorbing / releasing properties.

[0008]

MEANS FOR SOLVING THE PROBLEMS The inventors of the present invention have made earnest studies on hydrophilic gels and moisture absorbing / releasing materials in order to achieve the above-mentioned object, and as a result, for example, in a crosslinked body having a specific structure,
Hydrophilic gel made by absorbing a predetermined amount of polyhydric alcohol,
It was found that the moisture absorbing / releasing property is excellent, and the moisture absorbing / releasing material containing the above-mentioned hydrophilic gel is also excellent in handleability and moisture absorbing / releasing property, and has completed the present invention.

That is, in order to solve the above-mentioned problems, the hydrophilic gel of the invention according to claim 1 absorbs polyhydric alcohol in an amount of 50 parts by weight to 200 parts by weight in 1 part by weight of the crosslinked polymer. It is characterized by being done.

According to the above construction, the hydrophilic gel is such that 1 part by weight of the crosslinked polymer absorbs 50 parts by weight or more of the polyhydric alcohol. Therefore, since the hydrophilic gel absorbs more polyhydric alcohol than before, it is excellent in moisture absorption and desorption.

In order to solve the above-mentioned problems, the hydrophilic gel of the invention described in claim 2 is the hydrophilic gel according to claim 1, wherein the cross-linked polymer has the general formula (1) CH ₂ = CR-CO- (X) _n -Y (1) (In the formula, R represents a hydrogen atom or a methyl group, and X is
Represents an oxyalkylene group having 2 to 4 carbon atoms in which the mole fraction of oxyethylene groups is 50% or more based on all oxyalkylene groups, and Y represents an alkoxy group having 1 to 5 carbon atoms, a phenoxy group, or a carbon number 1 To (9) represent an oxyalkylphenyl group having 1 to 3 alkyl groups as a substituent, and n represents an integer of 3 to 100 on average). In addition, the ratio of the (meth) acrylic acid ester monomer to the total amount of both monomers of the above (meth) acrylic acid ester monomer is 20% by weight to 100% by weight. It is characterized by being obtained by polymerizing so as to be within the range of%.

According to the above constitution, the absorption performance of the crosslinked polymer for polyhydric alcohol and water can be further improved. This can further improve the absorption performance of the crosslinked polymer for water after the crosslinked polymer has absorbed the polyhydric alcohol, and thus can further improve the moisture absorption / release property of the hydrophilic gel. Also,
In the hydrophilic gel, the crosslinked polymer can efficiently absorb water and polyhydric alcohol even after absorbing moisture.

In order to solve the above problems, the hydrophilic gel of the invention of claim 3 is the hydrophilic gel of claim 1 or 2, wherein the polyhydric alcohol has 2 to 3 carbon atoms.
It is characterized by being.

According to the above construction, the moisture absorption / release property can be further improved.

In order to solve the above problems, the moisture absorptive and desorptive material of the invention of claim 4 is any one of claims 1 to 3 above.
It is characterized by comprising the hydrophilic gel described in the item.

According to the above construction, the moisture absorbing / releasing material is excellent in moisture absorbing / releasing property because it contains the hydrophilic gel having excellent moisture absorbing / releasing property. Moreover, the moisture absorbing / releasing material is excellent in handleability because the crosslinked polymer absorbs the polyhydric alcohol and gels.

In order to solve the above-mentioned problems, the moisture absorptive and desorptive material of the invention of claim 5 is the moisture absorptive and desorptive material of claim 4, wherein the moisture absorptive and desorptive material is at a temperature of 15 ° C and a relative humidity of 98%. It is characterized in that the subsequent liquefaction rate is 5% by weight or less.

According to the above construction, since the liquefaction rate is 5% by weight or less, when the moisture absorbing / releasing material is put into a breathable bag for use, the liquid does not seep out from the bag. Therefore,
Does not get wet around.

Hereinafter, the present invention will be described in detail. In the hydrophilic gel of the present invention, polyhydric alcohol is absorbed within the range of 50 to 200 parts by weight with respect to 1 part by weight of the crosslinked polymer. Further, the moisture absorbing / releasing material according to the present invention is made of the above hydrophilic gel.

If less than 50 parts by weight of the polyhydric alcohol is absorbed with respect to 1 part by weight of the crosslinked polymer, the moisture absorption and desorption property becomes insufficient, which is not preferable. In addition, cross-linked polymer 1
If more than 200 parts by weight of polyhydric alcohol is absorbed with respect to parts by weight, the liquefaction rate increases when moisture is absorbed, and for example, when used in a breathable bag, water is removed from the bag. It is not preferable because liquid such as ooze out.

The polyhydric alcohol is not particularly limited as long as 50 parts by weight to 200 parts by weight are absorbed with respect to 1 part by weight of the crosslinked polymer and the crosslinked polymer is gelated. As the polyhydric alcohol, ethylene glycol, propylene glycol, trimethylene glycol,
1,4-butanediol, 1,5-pentanediol,
1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, pinacol, hydrobenzoin, benzpinacol, cyclopentane-1,2.
-Diol, cyclohexane-1,2-diol, cyclohexane-1,4-diol, glycerin and the like. These polyhydric alcohols may be used alone,
Further, two or more kinds may be appropriately mixed and used. Among the above-exemplified polyhydric alcohols, polyhydric alcohols having 2 to 3 carbon atoms, that is, ethylene glycol, propylene glycol, trimethylene glycol, and glycerin, were easily absorbed by the crosslinked polymer and were also absorbed by the crosslinked polymer. It is particularly preferable since it can easily maintain the gel state later and is excellent in moisture absorption and desorption.

The above cross-linked polymer absorbs polyhydric alcohol in an amount of 50 to 200 parts by weight per 1 part by weight,
There is no particular limitation as long as it can absorb all polyhydric alcohols and gelate, but the (meth) acrylic acid ester-based monomer represented by the general formula (1), and the above ( 20% by weight of the (meth) acrylic acid ester-based monomer is a copolymerizable monomer with the (meth) acrylic acid ester-based monomer, based on the total amount of both monomers.
Polymers obtained by polymerization in the range of -100% by weight are preferred. As a result, the hydrophilic gel has excellent moisture absorption and desorption,
Moreover, even after moisture absorption, water and polyhydric alcohol can be almost completely absorbed, so that the liquefaction rate after moisture absorption can be suppressed.

In the (meth) acrylic acid ester-based monomer represented by the general formula (1) used in the present invention, the substituent represented by R in the formula is a hydrogen atom or a methyl group, and , The oxyalkylene group having 2 to 4 carbon atoms represented by X has a mole fraction of the oxyethylene group with respect to all the oxyalkylene groups of 50% or more, and further, the repeating of the oxyalkylene group represented by n is on average. 3-
An integer of 100, in addition, the terminal group represented by Y is an oxy group having 1 to 3 alkoxy groups having 1 to 5 carbon atoms, a phenoxy group, or an alkyl group having 1 to 9 carbon atoms as a substituent. It is an alkylphenyl group.

Examples of the above-mentioned (meth) acrylic acid ester monomers include methoxypolyethylene glycol mono (meth) acrylate, methoxypolyethylene glycol / polypropylene glycol mono (meth) acrylate, methoxypolyethylene glycol / polybutylene glycol mono ( (Meth) acrylate, ethoxy polyethylene glycol mono (meth) acrylate, ethoxy polyethylene glycol / polypropylene glycol mono (meth) acrylate, ethoxy polyethylene glycol / polybutylene glycol mono (meth) acrylate, phenoxy polyethylene glycol mono (meth) acrylate
Examples thereof include acrylate and benzyloxy polyethylene glycol mono (meth) acrylate. These compounds may be used alone or in combination of two or more.

Instead of the above compounds, for example, compounds such as alkoxy polypropylene glycol mono (meth) acrylate and phenoxypolybutylene glycol mono (meth) acrylate whose molar fraction is less than 50%, or, for example, terminal When a compound such as polyethylene glycol mono (meth) acrylate having a hydroxyl group in its part, that is, a compound in which the terminal part is not composed of a hydrophobic hydrocarbon group is used, the resulting crosslinked polymer is difficult to absorb the polyhydric alcohol. It is not preferable because the moisture absorbing / releasing material has a reduced moisture absorbing / releasing property, or the liquefying rate of the moisture absorbing / releasing material increases.

Used as necessary in the present invention,
The monomer copolymerizable with the (meth) acrylic acid ester-based monomer (hereinafter referred to as a copolymerized monomer) is not particularly limited, and various compounds can be used. Examples of the above-mentioned copolymerizable monomers include unsaturated monocarboxylic acid-based monomers such as acrylic acid, methacrylic acid, crotonic acid, and neutralized products or partially neutralized products thereof; maleic acid, fumaric acid, Itaconic acid, citraconic acid, and unsaturated dicarboxylic acid type monomers such as neutralized products and partially neutralized products thereof; vinyl sulfonic acid, allyl sulfonic acid, methallyl sulfonic acid, styrene sulfonic acid, 2-acrylamido-2 -Methylpropanesulfonic acid, sulfoethyl (meth) acrylate, sulfopropyl (meth) acrylate, 2-hydroxysulfopropyl (meth) acrylate, sulfoethylmaleimide, 3-allyloxy-2-hydroxypropanesulfonic acid, and neutralized products thereof. Unsaturated sulphonic acid type monomers such as or partially neutralized products; (meth) acrylamide, isopro Amide-based monomers such as acrylamide, t-butyl (meth) acrylamide; hydrophobic monomers such as (meth) acrylic acid ester, styrene, 2-methylstyrene, vinyl acetate; 2-hydroxyethyl (meth) acrylate , Polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, allyl alcohol, polyethylene glycol monoallyl ether, polypropylene glycol monoallyl ether, 3-methyl-3-butene-
1-ol (isoprenol), polyethylene glycol monoisoprenol ether, polypropylene glycol monoisoprenol ether, 3-methyl-2-buten-1-ol (prenol), polyethylene glycol monoprenol ether, polypropylene glycol monoprenol ether, 2-methyl-3-butene-
2-ol (isoprene alcohol), polyethylene glycol monoisoprene alcohol ether, polypropylene glycol monoisoprene alcohol ether,
Hydroxyl group-containing unsaturated monomers such as N-methylol (meth) acrylamide, glycerol mono (meth) acrylate, glycerol monoallyl ether, vinyl alcohol; cations such as dimethylaminoethyl (meth) acrylate and dimethylaminopropyl (meth) acrylamide Monomers; nitrile-based monomers such as (meth) acrylonitrile; (meth) acrylamidomethanephosphonic acid,
Examples thereof include phosphorus-containing monomers such as (meth) acrylamide methanephosphonic acid methyl ester and 2- (meth) acrylamido-2-methylpropanephosphonic acid. Also,
The unsaturated monocarboxylic acid-based monomer, the unsaturated dicarboxylic acid-based monomer, and the neutralized product or partially neutralized product of the unsaturated sulfonic acid-based monomer, a corresponding compound, a monovalent metal, It is obtained by neutralizing with a divalent metal, ammonia, or an organic amine. These copolymerizable monomers may be used alone, or two or more kinds may be appropriately mixed and used. Of these, unsaturated monocarboxylic acid-based monomers, unsaturated sulfonic acid-based monomers, and mixtures thereof are particularly preferred because of their excellent copolymerizability and low cost.

In the present invention, the (meth) acrylic acid ester-based monomer and the copolymerized monomer (hereinafter, both are collectively referred to as both monomers) are added to the total amount of both monomers (meta). ) 20% by weight of acrylic acid ester monomer
A crosslinked polymer is obtained by polymerizing within the range of ˜100% by weight.
That is, in the crosslinked polymer according to the present invention, the above-mentioned both monomers have a weight ratio ((meth) acrylic acid ester-based monomer / copolymerized monomer) of 20/80 to 100/0. Within range,
The polymerization is preferably carried out within the range of 40/60 to 90/10. When the above-mentioned proportion of the (meth) acrylic acid ester-based monomer is less than 20% by weight, the resulting crosslinked polymer becomes difficult to absorb the polyhydric alcohol, or the moisture absorption / desorption property of the moisture absorptive and desorptive material decreases. Or, the liquefaction rate of the moisture absorbing / releasing material increases, which is not preferable.

In the present invention, a solvent can be used when copolymerizing both monomers. Examples of the solvent include liquids in which both monomers are soluble, for example, water and hydrophilic organic solvents that are uniformly mixed with water. Examples of the organic solvent include methyl alcohol and ethyl alcohol. Examples include lower alcohols having 1 to 4 carbon atoms, lower ketones such as acetone, dimethylformamide, dimethylsulfoxide, and the like. These solvents may be used alone,
Further, two or more kinds may be appropriately mixed and used. In addition,
When two or more kinds of solvents are mixed, the mixing ratio may be appropriately set in consideration of the kinds of the above-mentioned both monomers. Further, when the polymerization reaction is carried out by the reverse phase suspension polymerization method (described later), a hydrophobic organic solvent can be used.

The amount of the above-mentioned solvent used, that is, the concentration of both monomers in the solvent (hereinafter referred to as the monomer concentration) is not particularly limited, but is easy to control the polymerization reaction, economical, Taking the reaction yield and the like into consideration, the monomer concentration is in the range of 20 wt% or more and the saturation concentration or less, preferably 30 wt% to
It may be set within the range of 95% by weight, and more preferably within the range of 55% by weight to 80% by weight. If the monomer concentration is less than 20% by weight, the amount of the solvent used becomes excessive, and the economical efficiency and the reaction yield decrease, which is not preferable. When the monomer concentration is equal to or higher than the saturation concentration, the polymerization reaction becomes non-uniform and it becomes difficult to remove the reaction heat of the polymerization reaction (polymerization heat), which is not preferable.

In the present invention, a crosslinking agent may be used when copolymerizing both monomers. Examples of the cross-linking agent include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate,
Propylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol di (meth) acrylate, N, N-methylenebisacrylamide, isocyanuric Acid compounds such as triallyl acid and trimethylolpropane diallyl ether having two or more ethylenically unsaturated groups in one molecule; ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, glycerin, polyglycerin, propylene glycol, diethanolamine, tri Ethanolamine, polypropylene glycol, polyvinyl alcohol, pentaerythritol, sorbit, sorbitan, glue Polyhydric alcohols such as glucose, mannitol, mannitol, sucrose, glucose; ethylene glycol diglycidyl ether, glycerin diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol Examples thereof include polyepoxy compounds such as diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane diglycidyl ether, trimethylolpropane triglycidyl ether, and glycerin triglycidyl ether. These cross-linking agents may be used alone, or two or more of them may be appropriately mixed and used.

By using a crosslinking agent, the crosslinking density of the obtained crosslinked polymer can be controlled to an arbitrary value.
Among the above-mentioned crosslinking agents, polyethylene glycol di (meth) acrylate is particularly preferable. Further, the number of added moles of ethylene oxide (hereinafter, referred to as EO) constituting polyethylene glycol di (meth) acrylate is preferably in the range of 4 to 100 moles, and from the viewpoint of crosslinking efficiency,
The range of 5 to 50 mol is particularly preferable.

Even when a compound other than polyethylene glycol di (meth) acrylate is used as the crosslinking agent, it is preferable to use polyethylene glycol di (meth) acrylate together with the compound.

The molar ratio of the cross-linking agent to the above two monomers is
The range of 1 × 10 ^{−5 to} 2 is preferable, and the range of 1 × 10 ⁻² to 1 is particularly preferable. When the molar ratio of the cross-linking agent is smaller than 1 × 10 ⁻⁵ , the cross-linking density of the obtained cross-linked polymer becomes too small, the cross-linked polymer becomes difficult to absorb polyhydric alcohol, and It is not preferable because the moisture absorption / desorption property is lowered or the liquefaction rate of the moisture absorption / desorption material is increased. When the molar ratio of the cross-linking agent is greater than 2, the cross-linking density of the resulting cross-linked polymer becomes too high, the cross-linked polymer becomes difficult to absorb polyhydric alcohol, and the moisture absorptive and desorptive property of the moisture absorptive and desorptive material is low. It is not preferable because it decreases or the liquefaction rate of the moisture absorbing / releasing material increases.

When a polyhydric alcohol is used as a cross-linking agent, the reaction product obtained after the polymerization reaction is
It is preferable to heat-treat at ℃ -250 ℃. When a polyepoxy compound is used as the crosslinking agent, it is preferable that the reaction product obtained after the polymerization reaction is heat-treated at 50 ° C to 250 ° C.

The above-mentioned cross-linked polymer is obtained by mixing both monomers in the presence of a cross-linking agent, a solvent, and a polymerization initiator, for example, by a known method such as a solution polymerization method, a suspension polymerization method, and a reverse phase suspension polymerization method. It is obtained by polymerization using a polymerization method. In addition, polymerization is carried out by so-called cast polymerization method, thin film polymerization method, spray polymerization method, or polymerization method in which a double-arm kneader is used as a reactor and the reaction product is subdivided by the shearing force of the kneader. By doing so, a crosslinked polymer can also be obtained.

The above-mentioned polymerization initiator is not particularly limited, but examples thereof include hydrogen peroxide; persulfates such as sodium persulfate, ammonium persulfate and potassium persulfate; 2,2′-azobis (2 -Amidinopropane) dihydrochloride, water-soluble azo compounds such as 4,4'-azobis (4-cyanovaleric acid); azobisisobutyronitrile, 2,
Oil-soluble azo compounds such as 2'-azobis (4-methoxy-2,4-dimethylvaleronitrile); organic peroxides such as benzoyl peroxide, lauroyl peroxide, peracetic acid, benzoyl peroxide, cumene hydroperoxide Radical polymerization initiators such as These polymerization initiators may be used alone, or two or more of them may be used as an appropriate mixture. Further, a reducing agent that accelerates the decomposition of these polymerization initiators may be used in combination, and a combination of both may be used as a redox initiator. The reducing agent is not particularly limited, but examples thereof include (bis) sulfurous acid (salt) such as sodium hydrogen sulfite, L
-Ascorbic acid (salt), reducing metal (salt) such as ferrous salt, amines and the like. Instead of using the polymerization initiator, the polymerization reaction may be performed by irradiating the reaction system with radiation, electron beams, ultraviolet rays, or the like.

As the dispersant for dispersing the aqueous solution of both monomers in the hydrophobic organic solvent when the reverse phase suspension polymerization method is carried out, for example, sorbitan fatty acid ester, sucrose fatty acid ester, glycerin fatty acid ester, poly Glycerin fatty acid ester, cellulose ester such as ethyl cellulose, cellulose acetate, cellulose ether, α
Examples include carboxyl group-containing polymers such as olefin-maleic anhydride copolymers. The hydrophobic organic solvent is not particularly limited.

The reaction temperature depends on the type and combination of both monomers, the crosslinking agent, the solvent, and the polymerization initiator, the amount used, etc., but the reaction is completed, and the molecular weight of the obtained crosslinked polymer is large. As such, relatively low temperatures are preferred. The reaction temperature is preferably in the range of 20 ° C to 100 ° C, for example. The reaction time is not particularly limited,
It may be appropriately set according to the reaction temperature and the like. Also, the reactor such as a polymerization vessel for carrying out the above-mentioned polymerization reaction is not particularly limited, but the reaction product obtained after the polymerization reaction can be easily crushed (described later). The so-called double-arm kneader is preferable.

The reaction system may be agitated or allowed to stand when carrying out the polymerization reaction. That is, the reaction system may be subjected to stirring polymerization, static polymerization, or a combination of stirring polymerization and static polymerization. Of these, static polymerization is most preferable. By carrying out static polymerization, a crosslinked polymer having an excellent absorption capacity for polyhydric alcohol can be efficiently produced. When performing static polymerization, it is preferable to crush the obtained reaction product after the polymerization reaction.

The reaction product obtained by the polymerization reaction is used as it is or, if necessary, as a sulfite salt, a hydrogen sulfite salt, a pyrosulfite salt, a dithionite salt, a nitrite salt, a phosphite salt, and hypophosphorous acid. An oxygen-containing reducing inorganic salt such as a salt is added to reduce the amount of residual monomer in the reaction product, and then the product is dried using a dryer or the like. Drying temperature is 100 ℃ ~ 160
C is preferable, and 120 to 140 C is more preferable. Further, it is particularly preferable to dry under reduced pressure (dry under reduced pressure) or to dry under an inert gas stream. The crosslinked polymer which is a dried product is pulverized as necessary using a pulverizer such as a hammer mill or a jet mill. Drying temperature is 1
When the temperature is lower than 00 ° C, it takes time to dry the reaction product sufficiently, which is not preferable. Drying temperature is 160 ℃
If it exceeds the range, the crosslinked polymer obtained by drying tends to deteriorate due to heat, and the absorption characteristics of the crosslinked polymer tend to deteriorate, such being undesirable.

The cross-linked polymer used in the present invention may be granulated into a predetermined shape, and may have various shapes such as irregular crushed shape, spherical shape, scale shape, fibrous shape, rod shape, and lump shape. Good. Further, the crosslinked polymer may be primary particles, or may be a granulated body of primary particles. The average particle size of the crosslinked polymer may be appropriately set in consideration of the types of both monomers used and the type of polyhydric alcohol. The method for granulating the crosslinked polymer is not particularly limited.

The surface of the crosslinked polymer may be subjected to various treatments or modifications in order to improve the permeability and dispersibility of the polyhydric alcohol. That is, the crosslinked polymer may be subjected to, for example, a surface treatment for introducing a crosslinked structure near the surface of the crosslinked polymer.

The surface cross-linking agent used in the above surface treatment can react with the carboxyl group and / or the carboxylate group when the cross-linked polymer contains the carboxyl group and / or the carboxylate group, for example. A compound having two or more functional groups in the molecule is suitable. Examples of the surface cross-linking agent include glycerin,
Polyhydric alcohols such as ethylene glycol and pentaerythritol; polyepoxy compounds such as ethylene glycol diglycidyl ether; polyamines such as ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine and polyethyleneimine; glutaraldehyde, Polyvalent aldehydes such as glyoxal; and polyvalent metal salts such as (poly) aluminum chloride, magnesium chloride, calcium chloride, aluminum sulfate, magnesium sulfate and calcium sulfate. These surface cross-linking agents may be used alone, or two or more of them may be appropriately mixed and used.

The amount of the surface-crosslinking agent used is not particularly limited, but is preferably in the range of 0.005% by weight to 5% by weight with respect to the crosslinked polymer. In addition, the treatment method for performing the above-described surface treatment is not particularly limited. For example, the surface cross-linking agent as it is in the powdery cross-linked polymer, or after mixing in the state of a solution dissolved in a suitable solvent,
Surface treatment may be performed by heating if necessary, and after the crosslinked polymer is dispersed in a hydrophobic organic solvent, a surface crosslinking agent is added to the dispersion, and then, if necessary. Surface treatment may be performed by heating.

Further, the cross-linked polymer is, if necessary, for improving processability and quality performance, a filler made of inorganic fine particles such as silica fine particles, pulp fiber and the like;
Activated carbon, carbon black, iron phthalocyanine derivative,
Deodorant or deodorant mainly composed of zeolite adsorbed vegetable essential oil etc .; fragrance; antibacterial agent mainly composed of metal such as silver, copper, zinc, etc., bactericide, fungicide, preservative; An oxygen absorber (antioxidant); a surfactant; a foaming agent; a coloring agent such as a pigment or a dye; a fragrance or the like may be added. By adding these additives, various functions can be imparted to the crosslinked polymer. The amount of the additive added is not particularly limited and may be appropriately set depending on the type of the additive, for example. The method of adding the additive is not particularly limited.

The crosslinked polymer obtained as described above is
By absorbing polyhydric alcohol, hydrophilic gel,
That is, a moisture absorbing / releasing material is obtained. That is, the method for absorbing the polyhydric alcohol in the crosslinked polymer may be, for example, a method in which the polyhydric alcohol is placed in a container and the crosslinked polymer is added (added) to the polyhydric alcohol. A method in which the combined product is placed in a container and a polyhydric alcohol is added (added) may be used. Therefore, the method of allowing the crosslinked polymer to absorb the polyhydric alcohol is not particularly limited. The temperature at which the crosslinked polymer absorbs the polyhydric alcohol is not particularly limited.

As described above, the hydrophilic gel according to the present invention contains 50 parts of polyhydric alcohol per 1 part by weight of the crosslinked polymer.
Absorbed within the range of 200 to 200 parts by weight.
According to the above configuration, the hydrophilic gel is excellent in moisture absorptive and desorptive properties since 50 parts by weight or more of the polyhydric alcohol having a superior moisture absorptive and desorptive property is absorbed with respect to 1 part by weight of the crosslinked polymer.

The hydrophilic gel according to the present invention is preferably used as a constituent material of a moisture absorbing / releasing material. By using the hydrophilic gel as the constituent material of the moisture absorbing / releasing material, the moisture absorbing / releasing material having excellent moisture absorbing / releasing property can be obtained. Moreover, since the cross-linked polymer absorbs the polyhydric alcohol and gels in the moisture absorbing / releasing material,
Excellent handleability.

The moisture absorptive and desorptive material of the present invention may contain other constituent materials in addition to the above hydrophilic gel. That is, as the above-mentioned other constituent materials, for example, fibers, non-woven fabrics, rubbers, synthetic resins and the like can be mentioned. And the hydrophilic gel,
A composite can be obtained by combining (compositing) with the above-mentioned other constituent materials and molding into a sheet shape or a fiber shape.

The hydrophilic gel of the present invention is not only suitable as a constituent material of a moisture absorbing / releasing material, but can also be used for other purposes. Hydrophilic gel, for example, when placed in water,
Since it can lower the melting point of water, it can be used as an antifreezing agent. Further, since the hydrophilic gel can lower the melting point of water even when it is brought into contact with ice (snow), it can be used also as an ice melting (snow) agent for melting ice (snow). Furthermore, since the hydrophilic gel absorbs a large amount of the medicinal component having the property of being easily absorbed by the cross-linked polymer, the medicinal component is effectively released.
It can be used as a patch.

The usage form of the moisture absorbing / releasing material is not particularly limited. The moisture absorbing / releasing material may be used by being enclosed in a bag made of a breathable material such as paper, non-woven fabric or woven fabric.

The use of the moisture absorbing / releasing material is not particularly limited. For example, when a bag containing a moisture absorbing / releasing material is hung in a closed room, it acts as a humidity adjusting agent for adjusting the indoor humidity to a substantially constant value. That is, the moisture absorbing / releasing material after once absorbing moisture acts as a dehumidifying agent when the humidity exceeds a certain humidity, and acts as a humidifying agent when the humidity is less than the certain humidity. As a result, the indoor humidity approaches the boundary humidity, and is adjusted to be substantially constant.
The boundary humidity can be arbitrarily set depending on the types and amounts of the crosslinked polymer and polyhydric alcohol.

Further, the moisture absorbing / releasing material which has sufficiently absorbed moisture in the high humidity space functions as a moisturizing agent in the low humidity space, and thus can be used as a moisturizing agent. On the other hand, since the dried moisture absorbing / releasing material acts as a dehumidifying agent, it can be used, for example, as a dew condensation preventing agent.

[0054]

The present invention will be described in more detail with reference to the following Examples and Comparative Examples, but the present invention is not limited thereto. The amount of moisture absorbed, the amount of moisture released, and the liquefaction rate of the moisture absorbing / releasing material were measured by the following methods. Further, “parts” described in Examples and Comparative Examples represent “parts by weight”, and “%” represents “% by weight”.

(A) Moisture Absorption and Moisture Release Amount 6 g of the moisture absorption and release material is placed on a petri dish having a diameter of 10 cm and placed in a thermo-hygrostat previously adjusted to a temperature of 15 ° C. and a relative humidity of 98% to absorb the moisture. The weight W ₁ (g) of the moisture absorbing / releasing material when the weight of the moisture absorbing / releasing material became constant was measured.

Then, from the weight W ₁ , the moisture absorption amount (g / g) according to the following equation, moisture absorption amount (g / g) = [(weight W ₁ (g) −6 (g) / 6/6 (g)] Was calculated.

Further, the above-mentioned moisture absorbing / releasing material after moisture absorption is put into a constant temperature / humidity machine previously adjusted to a temperature of 40 ° C. and a relative humidity of 40% to allow moisture to be released, and the weight of the moisture absorbing / releasing material becomes a constant amount. The weight W ₂ (g) of the moisture absorbing / releasing material was measured.

Then, from the weight W ₁ and the weight W ₂ , the following equation, moisture release amount (g / g) = [(weight W ₁ (g) -weight W ₂ (g)) / 6
(g)], the moisture absorption amount (g / g) was calculated.

(B) Liquefaction rate 10 g of the moisture absorbing / releasing material after moisture absorption is sandwiched between two sheets of square heatlon paper (GS-22, manufactured by Nankoku Pulp Industry Co., Ltd.) having a side of 5 cm, and 4 sides. Each was heat-sealed with a width of 5 mm. As a result, the moisture absorbing / releasing material is enclosed in the bag made of heatlon paper, and the weight W of the bag at that time is W.
₃ (g) was measured. Next, the bag in which the moisture absorbing / releasing material was enclosed was centrifuged by a centrifuge at a rotation speed of 1000 rpm to remove the released liquid, and then the weight W ₄ (g) of the bag was measured. Then, from the weight W ₃ and the weight W ₄ , the following equation, liquefaction rate (%) = [(weight W ₃ (g) -weight W ₄ (g)) /
The liquefaction rate (%) was calculated according to the weight W ₃ (g)] × 100. The weight of the heatlon paper and the amount of liquid absorbed by the heatron paper are extremely small and can be ignored. Therefore, the bag weight W ₃ (g) and the bag weight W
₄ (g) can be regarded as the weight of the moisture absorbing / releasing material itself.

[Example 1] A thermometer was attached to a table-top kneader with a jacket having an inner volume of 2.5 L whose inner surface was lined with ethylene trifluoride to prepare a reactor. Hot water is passed through the jacket. In this reactor, 250.0 parts of methoxypolyethylene glycol methacrylate (the number of moles of EO added: 9 moles) as a (meth) acrylic acid ester-based monomer and a 43% aqueous solution of sodium methacrylate as a comonomer 581.4
Parts, polyethylene glycol dimethacrylate as a cross-linking agent (the number of moles of EO added: 8 moles) 2.6 parts, and
164.8 parts of ion-exchanged water as a solvent was supplied as a reaction solution. In the above-mentioned methoxy polyethylene glycol methacrylate, R in the general formula (1) is a methyl group, X is ethylene oxide, Y is a methoxy group, and n is a methacrylic acid ester. The weight ratio of both monomers (methoxy polyethylene glycol methacrylate / sodium methacrylate) was 50/50. The ratio of polyethylene glycol dimethacrylate to both monomers is 0.2
Mole%.

Next, after the inside of the reactor was replaced with nitrogen, the blade of the kneader was rotated to stir while stirring the jacket.
The temperature of the reaction solution (reaction start temperature) is passed by passing hot water of 40 ℃.
Was heated to 40 ° C. Then, 1.16 parts of a 10% aqueous solution of 2,2′-azobis (2-amidinopropane) hydrochloride as a polymerization initiator was added to the reaction solution to initiate polymerization. After the addition, the mixture was stirred for 20 seconds, after which the stirring was stopped and the reaction solution was allowed to stand. The ratio of 2,2′-azobis (2-amidinopropane) hydrochloride to both monomers was 0.15 mol%.

After the addition of 2,2'-azobis (2-amidinopropane) hydrochloride, the polymerization reaction was started immediately.
After a lapse of minutes, the reaction temperature reached a peak and reached 84 ° C.
During this time, the temperature of the jacket rose to equal the contents. Then, pass 80 ° C warm water through the jacket,
The temperature of the reaction solution was kept at 80 ° C., and the hydrogel polymer as a reaction product was aged for 1 hour. After aging, rotate the kneader blade at 40 rpm for 10 minutes,
The hydrogel polymer was crushed. Next, the blade was inverted and the hydrogel polymer was taken out.

The hydrogel polymer having a fine particle size thus obtained was heated at 120 ° C. using a hot air circulation dryer.
It was dried at ℃ for 4 hours. Then, the crosslinked polymer which is a dried product was pulverized using a desktop simple pulverizer (manufactured by Kyoritsu Riko Co., Ltd.) to obtain a crosslinked polymer.

Then, 50 parts of glycerin as a polyhydric alcohol was added to 1 part of the crosslinked polymer to allow the crosslinked polymer to absorb glycerin. As a result, a hydrophilic gel, that is, a moisture absorbing / releasing material was obtained. Moisture absorption amount of the obtained moisture absorbing and releasing material,
The amount of moisture released was measured based on the method described above.

That is, 6 g of the moisture absorbing / releasing material was placed on a petri dish having a diameter of 10 cm, and the moisture absorbing / releasing material was placed in a thermo-hygrostat previously adjusted to a temperature of 15 ° C. and a relative humidity of 98% to absorb the moisture. When the weight W _{1 of the} moisture absorbing / releasing material when the constant weight of
It was 8.6g. That is, the amount of moisture absorption was 2.1 g / g under the above humidification conditions.

Further, the above-mentioned moisture absorbing / releasing material after moisture absorption is put into a constant temperature and humidity machine adjusted to a temperature of 40 ° C. and a relative humidity of 40% in advance to allow moisture to be released, and the weight of the moisture absorbing / releasing material becomes a constant amount. The weight W _{2 of the} moisture absorbing / releasing material when measured was 6.4 g. That is, the amount of moisture released was 2.0 g / g under the above humidification conditions.

Further, the liquefaction ratio of the moisture absorbing / releasing material was measured by the above-mentioned method and was found to be 0.3%. Table 1 shows the measurement results of the moisture absorption amount, the moisture release amount, and the liquefaction rate.

Example 2 To 1 part of a crosslinked polymer obtained in the same manner as in Example 1, 100 parts of glycerin as a polyhydric alcohol was added to allow the crosslinked polymer to absorb glycerin. As a result, a hydrophilic gel, that is, a moisture absorbing / releasing material was obtained. Table 1 shows the results of measuring the amount of moisture absorption, the amount of moisture released, and the liquefaction rate of the obtained moisture absorbing and desorbing material in the same manner as in Example 1.

Example 3 To 1 part of a crosslinked polymer obtained in the same manner as in Example 1, 50 parts of ethylene glycol as a polyhydric alcohol was added to allow the crosslinked polymer to absorb ethylene glycol. It was This makes the hydrophilic gel,
That is, a moisture absorbing / releasing material was obtained. Table 1 shows the results of measuring the amount of moisture absorption, the amount of moisture released, and the liquefaction rate of the obtained moisture absorbing and desorbing material in the same manner as in Example 1.

Example 4 In Example 1, sodium methacrylate was used alone as the comonomer, but in this Example, sodium methacrylate and acrylic acid were used as the comonomer. Was used as a mixture. The weight ratio of both monomers in the mixture (sodium methacrylate / acrylic acid) was set to 50/50. Weight ratio of methoxy polyethylene glycol methacrylate and the mixture (methoxy polyethylene glycol methacrylate /
The sum of sodium methacrylate and acrylic acid) is 50 /
A crosslinked polymer was obtained by carrying out the same reaction and operation as in Example 1 while setting the ratio to 50.

Then, 50 parts of glycerin was added to 1 part of the crosslinked polymer to absorb the glycerin in the crosslinked polymer. As a result, a hydrophilic gel, that is, a moisture absorbing / releasing material was obtained. Moisture absorption amount of the obtained moisture absorbing and releasing material,
Table 1 shows the results of measuring the amount of moisture released and the liquefaction rate in the same manner as in Example 1.

Example 5 The same reaction as in Example 1 except that the weight ratio of both monomers (methoxy polyethylene glycol methacrylate / sodium methacrylate) in Example 1 was changed from 50/50 to 20/80. Then, the operation was performed to obtain a crosslinked polymer.

Then, 50 parts of glycerin was added to 1 part of the crosslinked polymer in the same manner as in Example 1 to allow the crosslinked polymer to absorb glycerin. As a result, a hydrophilic gel, that is, a moisture absorbing / releasing material was obtained. Moisture absorption amount of the obtained moisture absorbing and releasing material,
Table 1 shows the results of measuring the amount of moisture released and the liquefaction rate in the same manner as in Example 1.

Example 6 The same reaction as in Example 1 except that the weight ratio of both monomers (methoxy polyethylene glycol methacrylate / sodium methacrylate) in Example 1 was changed from 50/50 to 95/5. Then, the operation was performed to obtain a crosslinked polymer.

Then, 50 parts of glycerin was added to 1 part of the crosslinked polymer in the same manner as in Example 1 to allow the crosslinked polymer to absorb glycerin. As a result, a hydrophilic gel, that is, a moisture absorbing / releasing material was obtained. Moisture absorption amount of the obtained moisture absorbing and releasing material,
Table 1 shows the results of measuring the amount of moisture released and the liquefaction rate in the same manner as in Example 1.

Example 7 In place of methoxypolyethylene glycol methacrylate (the number of moles of EO added: 9 moles) as the (meth) acrylic acid ester-based monomer in Example 1, butoxypolyethylene glycol methacrylate (addition of EO) was used. The same reaction and operation as in Example 1 were carried out except that the number of moles: 70 mol) was used to obtain a crosslinked polymer.

Then, 50 parts of glycerin was added to 1 part of the crosslinked polymer in the same manner as in Example 1 to allow the crosslinked polymer to absorb glycerin. As a result, a hydrophilic gel, that is, a moisture absorbing / releasing material was obtained. Moisture absorption amount of the obtained moisture absorbing and releasing material,
Table 1 shows the results of measuring the amount of moisture released and the liquefaction rate in the same manner as in Example 1.

[Example 8] To 1 part of the crosslinked polymer obtained in the same manner as in Example 4, 200 parts of glycerin as a polyhydric alcohol was added to allow the crosslinked polymer to absorb glycerin. As a result, a hydrophilic gel, that is, a moisture absorbing / releasing material was obtained. Table 1 shows the results of measuring the amount of moisture absorption, the amount of moisture released, and the liquefaction rate of the obtained moisture absorbing and desorbing material in the same manner as in Example 1.

Comparative Example 1 As the moisture absorbing / releasing material, only the crosslinked polymer obtained in Example 1 was used. Table 1 shows the results of measuring the amount of moisture absorption, the amount of moisture released, and the liquefaction rate of the crosslinked polymer in the same manner as in Example 1.

Comparative Example 2 Only glycerin was used as the moisture absorbing / releasing material. Table 1 shows the results of measuring the amount of absorbed moisture, the amount of released moisture, and the liquefaction rate of glycerin in the same manner as in Example 1.

Comparative Example 3 To 1 part of a crosslinked polymer obtained in the same manner as in Example 4, 40 parts of glycerin as a polyhydric alcohol was added to allow the crosslinked polymer to absorb glycerin. As a result, a hydrophilic gel, that is, a moisture absorbing / releasing material was obtained. Table 1 shows the results of measuring the amount of moisture absorption, the amount of moisture released, and the liquefaction rate of the obtained moisture absorbing and desorbing material in the same manner as in Example 1.

Comparative Example 4 To 1 part of a crosslinked polymer obtained in the same manner as in Example 4, 250 parts of glycerin as a polyhydric alcohol was added to allow the crosslinked polymer to absorb glycerin. As a result, a hydrophilic gel, that is, a moisture absorbing / releasing material was obtained. Table 1 shows the results of measuring the amount of moisture absorption, the amount of moisture released, and the liquefaction rate of the obtained moisture absorbing and desorbing material in the same manner as in Example 1.

[0083]

[Table 1]

As is clear from the results of Examples 1 to 8 shown in Table 1, the moisture absorbing / releasing material of this example, that is, the hydrophilic gel, has a large amount of moisture absorption and moisture release, and has a high moisture absorption / desorption property. Is excellent. In addition, since the moisture absorbing / releasing material of this embodiment has a low liquefaction rate after absorbing moisture, when the moisture absorbing / releasing material is placed in a bag having air permeability to absorb moisture, the liquid does not exude from the bag. Therefore, the surroundings will not get wet.

[0085]

As described above, the hydrophilic gel according to the first aspect of the present invention is configured such that 1 part by weight of the crosslinked polymer absorbs the polyhydric alcohol within the range of 50 parts by weight to 200 parts by weight. .

As a result, there is an effect that it is possible to provide a hydrophilic gel excellent in moisture absorption and desorption.

The hydrophilic gel according to claim 2 is the same as the hydrophilic gel according to claim 1, wherein the crosslinked polymer has the general formula (1) CH ₂ = CR-CO- (X) _n -Y. (1) (In the formula, R represents a hydrogen atom or a methyl group, and X represents
Represents an oxyalkylene group having 2 to 4 carbon atoms in which the mole fraction of oxyethylene groups is 50% or more based on all oxyalkylene groups, and Y represents an alkoxy group having 1 to 5 carbon atoms, a phenoxy group, or a carbon number 1 To (9) represent an oxyalkylphenyl group having 1 to 3 alkyl groups as a substituent, and n represents an integer of 3 to 100 on average). In addition, the ratio of the (meth) acrylic acid ester monomer to the total amount of both monomers of the above (meth) acrylic acid ester monomer is 20% by weight to 100% by weight. The composition is obtained by polymerizing so as to be within the range of%.

As a result, it is possible to provide a hydrophilic gel which is particularly excellent in moisture absorption and desorption.

The hydrophilic gel according to claim 3 is the hydrophilic gel according to claim 1 or 2, wherein the polyhydric alcohol has 2 to 3 carbon atoms.

As a result, there is an effect that it is possible to provide a hydrophilic gel having a further excellent moisture absorption / release property.

The moisture absorptive and desorptive material according to a fourth aspect is the above-mentioned first aspect.
To 3, the hydrophilic gel according to any one of 3 to 3 is included.

According to the above constitution, the moisture absorbing / releasing material contains a hydrophilic gel having excellent moisture absorbing / releasing properties. Further, according to the above configuration, in the moisture absorbing / releasing material, the cross-linked polymer absorbs the polyhydric alcohol and gels. Due to these, there is an effect that it is possible to provide a hydrophilic gel which is excellent in moisture absorption / release properties and handleability.

The moisture absorbing / releasing material according to claim 5 is characterized in that the liquefaction rate after moisture absorption is 5% by weight or less under the conditions of a temperature of 15 ° C. and a relative humidity of 98%.

According to the above construction, when the moisture absorbing / releasing material is put into the breathable bag for use, the liquid does not seep out from the bag. As a result, it is possible to prevent the surroundings from getting wet.

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location // C08F 299/02 MRS C08F 299/02 MRS

Claims (5)

[Claims] 1. A polyhydric alcohol is added to 1 part by weight of a crosslinked polymer.
A hydrophilic gel characterized by being absorbed in the range of 50 to 200 parts by weight. 2. The crosslinked polymer has the general formula (1) CH ₂ ═CR—CO— (X) _n —Y (1) (wherein R represents a hydrogen atom or a methyl group, and X represents Is
Represents an oxyalkylene group having 2 to 4 carbon atoms in which the mole fraction of oxyethylene groups is 50% or more based on all oxyalkylene groups, and Y represents an alkoxy group having 1 to 5 carbon atoms, a phenoxy group, or a carbon number 1 To (9) represent an oxyalkylphenyl group having 1 to 3 alkyl groups as a substituent, and n represents an integer of 3 to 100 on average). In addition, the ratio of the (meth) acrylic acid ester monomer to the total amount of both monomers of the above (meth) acrylic acid ester monomer is 20% by weight to 100% by weight. The hydrophilic gel according to claim 1, which is obtained by polymerizing so as to be within the range of%. 3. The hydrophilic gel according to claim 1, wherein the polyhydric alcohol has 2 to 3 carbon atoms. 4. A moisture absorbing / releasing material comprising the hydrophilic gel according to any one of claims 1 to 3. 5. The moisture absorptive and desorptive material according to claim 4, which has a liquefaction rate of 5% by weight or less after moisture absorption under the conditions of a temperature of 15 ° C. and a relative humidity of 98%.