JPH01121317A - Hydrous gel - Google Patents

Abstract

PURPOSE:To obtain the title gel, having excellent strength and transparency with extremely low water separating properties and useful as a gel insecticide, etc., without requiring high-temperature treatment, by crosslinking a modified PVA having reactive groups introduced thereinto in a hydrous state. CONSTITUTION:The aimed gel consisting of (A) a copolymer having structural units expressed by the formula (R1 is H or methyl; R2-R4 are H or alkyl; n1 is 1 or 2; n2 is 1, 2 or 3) and vinyl alcohol structural units, (B) a crosslinking agent for the component (A) and (C) water. Furthermore, the component (B) is preferably a curing agent for epoxy resins and/or curing catalyst and especially an amine compound is preferably used.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a novel hydrogel. More specifically, the present invention relates to a hydrous resin obtained by crosslinking modified polyvinyl alcohol into which a reactive group has been introduced in a hydrous state.

The hydrous gel obtained by the present invention has excellent strength and transparency, and has extremely low water repellency, and can be used as a heat retention material, a gel deodorant, a gel insecticide, a gel fragrance, a medical drug release carrier, etc. Yes, its application range is wide.

[Conventional technology]

Conventionally, water-containing ingredients include starch, calamari, gelatin,
Natural or synthetic water-soluble monomers such as casein, polyvinyl alcohol, polyvinylpyrrolidone, and polyacrylic acid are widely used as raw materials.

However, hydrogels made from natural products require treatment at a high temperature of 80 to 100°C for dissolution and gelation, and are often subject to restrictions in terms of use. Another disadvantage is that the obtained hydrous delus is brittle and soft.

On the other hand, as a glue using a synthetic substance, for example, there is a gel obtained by adding an inorganic salt or acid such as borax, boric acid, titanium chloride, or a metal compound to polyvinyl alcohol (
(For example, Japanese Patent Publication No. 44-19884) These have drawbacks such as lack of homogeneity, repeated freezing and thawing, and water release on the surface when kept at high temperatures.

Furthermore, as a method for producing glue using modified water-soluble polymers, acetoacetylated water-soluble polymers obtained by acetoacetylating water-soluble polymers such as polyvinyl alcohol, hydroxyethyl cellulose, and hydroxypropyl cellulose (with diketene) are also available. A method using a combination of a polymer and a crosslinking agent has been proposed (Japanese Unexamined Patent Publication No. 112604/1983). The del obtained by this method is superior to the del obtained from conventional water bathing polymers in terms of hardness and water repellency, but it lacks elasticity when subjected to strong deformation. For example, when the glue is bent, it may crack or break.

[Problem that the invention seeks to solve]

Conventional hydrogels using natural or synthetic materials have had problems such as requiring high temperatures for gel formation, insufficient gel homogeneity and strength, and high water repellency.

[Means for resolving subgroup points]

The present invention is based on the general formula [wherein R1 is a hydrogen atom or a methyl group, R2, R, , R
4 is a hydrogen atom or an alkyl group, nl is 1 or 2, and R2 is 1, 2 or 3. ) crosslinking agent (b)
and water (C).

In the formula, R1 is a hydrogen atom or a methyl group, R2, R3 and R
4 is a hydrogen atom or an alkyl group, and R1 is preferably a hydrogen atom, and R2, R3 and R3 are preferably hydrogen atoms or methyl groups. The resins used in the present invention include vinyl alcohol (saponified product of vinyl acetate S component, hereinafter abbreviated as VA)/allyl glycidyl ether copolymer, VA/(meth)allyl glycidyl ether copolymer, vA/1- (3
-butenyloxy)-2,3-epoxypropane copolymer, VA・1-allyloxy-3,4-epoxybutane copolymer, VA・1-allylox'1-as5-xdt
1-allyloxy-6,4-epoxypentane copolymer, vA・1-allyloxy-6,4-epoxy-6-methylpentane copolymer, VA・1-allyloxy-4,
5-epoxy-4-methylpentane copolymer, vA・1
-allyloxy-485-epoxyhexane comonomer,
vA.1-allyloxy-4,5-epoxy-4-methylhexane copolymer, VA.methallyl-methylglycidyl ether copolymer, vA.methallyl-dimethylglycidyl ether copolymer, etc. are used. As the third copolymer unit, vinyl ester units (for example, vinyl acetate units), α-olefins such as ethylene and progylene, acids such as (meth)acrylic acid, crotonic acid, itaconic acid, and fumaric acid, and their alkyl esters, ( meth)acrylamide, alkyl vinyl ether, 2-acrylamide-2~
Methylpropanesulfonic acid and the like may be contained to an extent that does not impair the properties of the hydrous gel of the present invention.

A method for producing the epoxy group-containing PVA comonomer used in the present invention has already been proposed in JP-A-60-195103. The content of the epoxy group structural unit in the copolymer is preferably in the range of 0.01 to 20 moles. If the amount is less than 0.01 molar ratio, the crosslinking density may be too low, resulting in disadvantages such as a decrease in the strength of the glue and an inability to increase the water content. If the amount exceeds 20 moles, the stability of the cohesive mold may be reduced and the crosslinking reaction may be too rapid, which may cause problems in handling.

The degree of polymerization and degree of saponification are appropriately selected depending on the desired properties of the gel, but the higher the degree of polymerization, the higher the efficiency of cross-linking.
This is preferable because a strong gel can be obtained even if the water content is increased. It is usually selected from the range of polymerization degree of 200 to 5,000 (number average molecular weight of 5,000 to 200,000). The degree of saponification is usually preferably 70 to 100 molar.

The water-containing gel of the present invention may be a gel obtained not only from a polymer having an epoxy structural unit and a vinyl alcohol structural unit alone, but also from a combination system with an ordinary PVA-based monomer that does not contain an epoxy group. normal P
As the VA polymer, for example, any polymer containing a vinyl alcohol structural unit can be used. Unmodified PVA made by polymerizing and saponifying vinyl ester such as vinegar vinegar
, vinyl ester and ethylene, (meth)acrylic acid,
(meth)acrylamide, alkyl vinyl ether, (
Examples include saponified copolymers with ethylenically unsaturated monomers such as methacrylic acid esters, maleic anhydride, and itaconic acid, and those obtained by post-modification of PvA by chemical reactions, graft reactions, etc.

The degree of polymerization and degree of saponification are arbitrarily selected depending on the use.

The crosslinking agent used in the present invention is mainly an epoxy resin curing agent or curing catalyst, and examples of the epoxy resin curing agent include n-propylamine, n-butylamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, metaxylylene diamine. , diethylaminoprotamine, diaminodiphenylmethane, cy-n-butylamine, cy-iso-butylamine, piperidine, 2
Examples include primary and tertiary amines such as gibecolin, imidazoles such as 2-methylimidazole, 2-ethyl-4-methylimidazole, and 2-phenylimidazole, and liquid polyamide resins.

Examples of curing catalysts for epoxy resins include tertiary amines such as trimethylamine, triethylamine, and tri-n-butylamine, and complex compounds of Lewis acids and amines such as fluorine trifluoride/ethylamine complexes.

The crosslinking agent in the hydrogel of the present invention is preferably water-soluble, and water-soluble amines are preferred in the sense that the gelation time and degree of gelation can be controlled by changing the amount added. It is also possible to use multiple crosslinking agents together.

The amount of crosslinking agent used varies depending on its type and the amount of modification of the polymer, but it is usually 0.01 to 2 parts by weight per 100 parts by weight of the polymer.
0 parts by weight is suitable. 0.01! (If the amount is less than 20 parts by weight, the crosslinking density will be insufficient, and it will not be possible to increase the strength or water content, and even if it exceeds 20 parts by weight, the crosslinking density of the dull will hardly change.) If it is too short, it may even have the opposite effect.

The water content of the water-containing gel of the present invention is usually selected from the range of 60 to 98XN% depending on the desired properties of the gel, but is preferably 80 to 95% by weight as a carrier for deodorants, fragrances, etc.

As a method for producing the hydrous delta of the present invention, it is possible to use an extremely simple method of dissolving or dispersing the crosslinking agent in a t-bath solution in an aqueous solution, pouring it into a mold of the desired shape, and leaving it at room temperature. The time required for delification depends on the amount of modification of the polymer,
Although it varies greatly depending on the concentration of the 1-coalescence aqueous solution, the type of crosslinking agent, the amount added, etc., it usually takes about several tens of minutes to one week at room temperature. This gelation time can be easily shortened by heating. Therefore, the properties of the desired gel are mainly determined by the amount of modification of one polymer, the concentration of the polymer, the type of crosslinking agent, and the amount added. A common method is to control the temperature at a desired time by setting it arbitrarily within the temperature range.

In addition, in the production of hydrous Del, commonly used additives such as colorants, freezing point depressants such as alcohols, and fragrances such as jasmine and lavender are dissolved in an aqueous polymer solution or dispersed by adding an emulsifier. It can also be added.

〔Example〕

Hereinafter, the present invention will be specifically explained using Examples, but these Examples will help in understanding the present invention, and the present invention is not limited to these Examples. "Department"
"parts by weight" means "% by weight" unless otherwise specified.

Synthesis Example 1 Into a 31 separable flask equipped with a stirrer, thermometer, reflux condenser, and dropping funnel, 2,000 parts of vinyl acetate, 2. z-
0.6 parts of azobisisobutyronitrile and 10 parts of allyl glycidyl ether were charged, and after deoxidizing by bubbling nitrogen gas, copolymerization was carried out at 60°C for 5 hours while dropping 10 parts of allyl glycidyl ether. The solid content concentration of the comonomer was 50.2% by weight.

After removing unreacted monomers by blowing methanol vapor into the polymerization reaction solution, a 25% methanol solution of the comonomer was prepared at 30°C. To 2,740 parts of this methanol solution, add 2-2N hydroxide) IJ Kumu's methanol solution 1
When 8 parts were added and mixed, the system became viscous and particles precipitated after 75 minutes. After washing with methanol, the mixture was dried to obtain a white comonomer.

Synthesis Examples 2 to 5 Copolymerization, saponification, and post-treatment were carried out in the same manner as in Synthesis Example 1, except that a predetermined amount of the monomer shown in Table 1 was used.

Table 1 shows the properties of the copolymers obtained in Synthesis Examples 1 to 5.

Examples 1 to 10 Each of the epoxy group-modified PvA obtained in Synthesis Examples 1 to 5 was made into a water bath solution with the concentration shown in Table 21C, and the crosslinking agent shown in Table 2 was added and mixed to 100nX100nX70.
The mixture was poured into a container and left at room temperature for 24 hours to obtain a hydrogel. The resulting gel was evaluated for transparency, hardness, and elasticity. For comparison, data on a gel prepared from a 3% aqueous solution of a commercially available agar bed (reagent) is also shown.

Examples 11 to 15 Gels were produced under the same conditions as Examples 1 to 5, and the water repellency at low and high temperatures was evaluated. For comparison, the degree of polymerization is 1700,
Hokusand T-
Dels obtained in the same manner as in the examples were also evaluated by mixing 3% additive. The results are shown in Cloth-3.

1) Del was placed in an airtight container and left at -30°C for 24 hours to freeze, then thawed at room temperature, and evaluated by calculating the separation water wheel according to the following formula.

Town Wl: Weight of gel before test 2) Weight of gel after freezing and thawing, measured after removing from airtight container and thoroughly wiping off free water 2) Place the gel in an airtight container and heat at 70°C. The water separation rate after being left for 24 hours was similarly calculated and evaluated.

It can be seen that the hydrogels according to the present invention shown in Tables 2 and 3 are excellent in strength, elasticity, transparency, and water repellency.

〔Effect of the invention〕

The hydrated delta of the present invention can be used as a special drug carrier for high-temperature treatment and the like.

Patent applicant Denki Kagaku Kogyo Co., Ltd.

Claims (3)

[Claims] (1) General formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [In the formula, R_1 is a hydrogen atom or a methyl group, R_2, R_3
, R_4 is a hydrogen atom or an alkyl group, n_1 is 1 or 2
, n_2 represents 1, 2 or 3] A copolymer (a) having a structural unit represented by and a vinyl alcohol structural unit, a crosslinking agent (b) for the copolymer (a)
and water (c). (2) The hydrogel according to claim (1), wherein the crosslinking agent is an epoxy resin curing agent and/or a curing catalyst. (3) Claim No. 1 in which the crosslinking agent is an amine compound (
The hydrogel described in section 1).