JPS6150493B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention provides a reaction product (a) obtained by reacting a copolymer of a vinyl compound or a vinylidene compound with maleic anhydride with ammonia, a polyvalent amine (gelling agent) (b) and water (c). The present invention relates to a hydrogel obtained by gelling a mixture formed by mixing the above in a water-containing state. Currently, examples of substances that form hydrogels that are generally known include starch, carrageenan, cellulose derivatives, gelatin, casein, polyvinyl alcohol, polyvinylpyrrolidone, polyacrylic acid,
There are water-soluble polymers such as polyoxyethylene oxide, and hydrogels made using these water-soluble polymers are widely used in applications such as fragrance preservation materials, fire prevention materials, heat insulation materials, and cold insulation materials. However, hydrogels made using these water-soluble polymers are generally manufactured using complicated methods, such as those that require a gelation reaction at a fairly high temperature, or are stable only at temperatures below 0°C. When a clean hydrogel cannot be formed, or when the gelation reaction cannot be promoted unless the pH of the aqueous solution is strictly controlled, there are few substances that can be easily formed into a gel, and when the water content of the hydrogel is high. In most cases, the gelation reaction is slow. In addition,
Currently used hydrogels made of such water-soluble polymers have various drawbacks. In other words, one of them is a soft hydrogel that has fluidity and has stress dispersion properties when stress is applied, to a high-containing gel that easily deforms when stress is applied and recovers as soon as the stress is removed. Hydrogels with a range of gel strengths up to elastomeric gels cannot be produced from a single water-soluble polymer. Another drawback is the drawback seen in the cold insulation material etc. according to the invention by Ohno et al. The invention is based on the carbonation of copolymers of monomers with ethylenic double bonds, such as vinyl acetate, acrylic esters, and styrene, and polymerizable unsaturated carboxylic acids, such as acrylic acid, crotonic acid, itaconic acid, and maleic acid. This relates to a heat transfer medium for cold storage made by mixing alkaline substances such as soda, caustic soda, ammonia, and amines with water. However, since it is an aqueous solution, it is not in the form of a gel, but is fluid and has extremely poor stability. Such drawbacks are also seen in the conventional hydrogels mentioned above. That is, if a hydrogel is left for a long time, water or the solvent contained therein may be liberated on the surface of the hydrogel, or the strength of the gel may gradually decrease.
This is especially noticeable when repeated freezing and thawing cycles or when left at 40-60°C. The main object of the present invention is to provide a hydrogel with excellent stability, which is very easy to manufacture and can be freely selected to have a desired gel strength. Another major purpose is that it is stable against freezing, high temperatures, repeated repetitions of these, or alkalis and acids, and is capable of liberating and decomposing the water and other substances contained therein, so that the gel strength increases over time. The purpose of the present invention is to provide a stable water-containing gel that does not deteriorate in quality. Another object of the present invention is to provide a hydrogel with excellent surface friction strength and bending strength. According to the present invention, the above object is achieved by using a reaction product (a) obtained by reacting a copolymer of a vinyl compound or vinylidene compound and maleic anhydride with ammonia, having the general formula H-(NH-CH ₂ -CH ₂ -) _o NH ₂ (However, in the formula, n is an integer from 1 to 50.) A mixture formed by blending polyvalent amine (gelling agent) (b) and water (c). This is achieved by a hydrogel obtained by gelation treatment. Particularly in terms of improving surface friction strength and bending strength, significant effects are observed when polyvinyl alcohol is further added to the mixture. A reaction product obtained by reacting ammonia with a copolymer of a vinyl compound or vinylidene compound monomer used in the present invention and maleic anhydride.
(a) is obtained by reacting a copolymer obtained by radical polymerization of a vinyl compound or vinylidene compound and maleic anhydride in a solvent with ammonia. Here, the vinyl compound or vinylidene compound means an unsaturated compound that can be copolymerized with maleic anhydride, such as α-olefin, styrene, vinyl chloride, vinyl acetate, vinyl propionate, acrylonitrile, methyl vinyl ether, acrylic ester. or vinyl alcohol obtained by saponifying vinyl acetate. Note that α-olefin means a linear or branched unsaturated hydrocarbon having 2 to 12 carbon atoms, preferably 2 to 8 carbon atoms, and examples thereof include ethylene,
Propylene, 1-butene, 2-butene, isobutylene, n-pentene, isoprene, 2-methyl-
1-butene, n-hexane, 2-methyl-1-pentene, 3-methyl-1-pentene, 4-methyl-pentene, 2-ethyl-1-butene, diisobutylene, 2-methyl-4-dimethyl-1 -pentene and 2-methyl-4-dimethyl-2-pentene. Here, isobutylene also means return BB containing isobutylene. These monomers may be used alone or in combination of two or more. Among these monomers, α-olefins, especially ethylene,
α-olefins such as isobutylene or methyl vinyl ether are preferably used. In particular, the use of isobutylene also meets the intended purpose of the invention. What is the composition ratio of the vinyl compound or vinylidene compound and maleic anhydride in the copolymer, as long as the reaction product obtained by reacting the copolymer with ammonia is soluble in water? There is no problem even if there is. In the case of each copolymer of ethylene, isobutylene or methyl vinyl ether and maleic anhydride preferably used in the present invention, the amount of ethylene, isobutylene or methyl vinyl ether is about 1 to 3 moles per 1 mole of maleic anhydride. Preferably, the alternating copolymers are about the same molar amount. In addition, the molecular weight of the copolymer is determined by the intrinsic viscosity measured at 30°C in dimethylformamide solution from 0.05 to 5.
(dl/g), preferably about 0.1 to 3 (dl/g). Various methods can be adopted for the reaction between the copolymer and ammonia, including a method in which solid powder of the copolymer is brought into contact with ammonia gas, and a method in which the copolymer powder is dispersed in a slurry form in a solvent to react with ammonia gas. A method of bringing the copolymer powder into contact with the solvent while bubbling it into the solvent, or a method of dissolving the copolymer powder in aqueous ammonia, etc., are preferably employed. The reaction ratio of ammonia to the copolymer is 0.5 to 2 mol, preferably 1 to 2 mol, of ammonia per 1 mol of maleic anhydride groups contained in the copolymer. Although sodium hydroxide and monovalent amines can be used to make the above-mentioned copolymers water-soluble, they do not provide the desired hydrogel in the present invention.
That is, the use of ammonia is essential and unique in the present invention. Furthermore, in the present invention, polyvinyl alcohol is used to improve the surface friction strength and bending strength of the hydrogel, but polyvinyl alcohol is
Saponified polyvinyl acetate with a polymerization degree of 200~
5000, preferably 300 to 3000, and a saponification degree of 70% or more. Specific examples thereof include fully saponified polyvinyl alcohol, partially saponified polyvinyl alcohol, partially urethanized or partially acetalized. Examples include polyvinyl alcohol that has undergone modification such as chemical conversion, or modified polyvinyl alcohol containing an ethylene group or other group. If the degree of polymerization is small, it will have little effect on improving the physical properties, and if it is too large, the viscosity of the aqueous solution will increase, which will cause problems when producing a hydrogel. Polyvinyl alcohol is added in the form of a powder or an aqueous solution to the powder or aqueous solution of the reaction product (a) obtained by reacting the vinyl compound or copolymer of a vinylidene compound and maleic anhydride with ammonia. Sometimes mixed. The amount added varies depending on the use of the hydrogel, but is preferably 20% or less, preferably 0.5% of the total weight of the hydrogel.
~5% is desirable. In addition, in the present invention, polyamides represented by the general formula H-(NH-CH ₂ -CH ₂ -) _o NH ₂ (wherein n represents an integer of 1 to 50) are used as the gelling agent (b). The amines include, for example, ethylenediamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, linear polyethyleneimine, or branched polyethyleneimine, and those with a large number of n in the above formula can also be used. . However, when the number n exceeds 50, the gelation rate is very fast and gelation occurs partially, making it impossible to form a uniform hydrogel, making it unsuitable for use. Note that even if ammonia or a monovalent amine is used, the desired object of the present invention cannot be obtained. The method for producing a hydrogel of the present invention includes 1 to 60% by weight of the reaction product of the above-mentioned copolymer and ammonia.
0.1 to 20% by weight, preferably 0.3 to 10% by weight of the above-mentioned polyvalent amine to the aqueous solution, based on the reaction product.
This is carried out by adding and mixing to form a uniform aqueous solution, pouring the aqueous solution into a desired mold, etc., and gelling it at room temperature or under heating. The time required for gelation varies depending on the type of copolymer, its concentration, the type of gelling agent, its concentration, and gelling temperature, and can be selected according to needs, but in general it is several minutes. ~10-odd days. For example, the gelation reaction speeds up as the gelation temperature increases, but even if the aqueous solution of the reaction product of the copolymer and ammonia has a low concentration of about 5 to 10%, the gelation reaction will proceed sufficiently at room temperature. By doing this, you can set the desired time. Furthermore, the gel strength of the produced hydrogel can be adjusted freely by similarly selecting the types and concentrations of the copolymer and gelling agent. In addition, when producing the hydrogel, various commonly used compounding agents are added, and depending on the intended use, for example, fragrance when used as a fragrance preservation material, or fragrance when used as a cold preservation material. Various organic solvents such as anti-icing agents can be added. For example, in cold insulation materials, monohydric alcohols such as methanol, ethanol, and isopropanol, and monohydric alcohols such as ethylene glycol, glycerin, and 3-methyl-1,3,5-pentatriol are added to the water component contained in the hydrogel to avoid the freezing point of water. An anti-icing agent can be mixed and used. In particular, by mixing and using a polyhydric alcohol, it is possible to obtain a water-containing gel that does not freeze even at -30 to -10°C and has a well-balanced flexibility and elasticity. Note that even when these organic solvents are used, there is no problem in producing the hydrogel, and its properties and stability are not impaired in any way. As mentioned above, the gel of the present invention can be widely used in applications such as fragrance preservation materials, cold preservation materials, fire prevention materials, heat insulation materials, heat absorbing materials, and lubricating materials. In addition, when the hydrous gel of the present invention is applied to nonwoven fabrics, woven fabrics, paper, etc. and then dried, it absorbs several times to several hundred times its weight of water and swells, and does not release free water. It can be used as a water-absorbing agent in diapers, sanitary products, etc. EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited thereto. Example 1 100 parts by weight of isobutylene-maleic anhydride alternating copolymer ([η] = 1.06, Isoban-10 manufactured by Clareisoprene Chemical Co., Ltd.) was stirred in a container and ammonia gas was blown into the isobutylene-maleic anhydride copolymer. 117 parts by weight of a reaction product of the alternating copolymer and ammonia (hereinafter abbreviated as ammonia adduct) was prepared. An aqueous solution was prepared by mixing 10 parts by weight of this ammonia adduct and 90 parts by weight of water. Next, 0.3 parts by weight of tetraethylenepentamine was added to this aqueous solution, stirred, and then allowed to stand at various temperatures. At 20°C, the reaction time was 6 hours, at 30°C, 3 to 4 hours, and at 40°C, 1 to 2 hours. and gelatinized in 10-20 minutes at 60°C. The hydrous gel obtained in this way is uniform and transparent, does not release water on the gel surface even after repeated freezing and thawing, and remains flexible even after being left in an atmosphere at 50°C for 10 days. It was not obvious, and furthermore, the deformation was not clearly recognized. Example 2 185 parts by weight of water was added to 15 parts by weight of the ammonia adduct of the isobutylene-maleic anhydride alternating copolymer used in Example 1 to prepare an aqueous solution. 200 g of this aqueous solution was placed in a beaker with a diameter of 6.5 cm and a height of 8 cm, and various polyvalent amines shown in Table 1 were added thereto to prepare a uniform and transparent aqueous solution. The aqueous solution thus obtained was allowed to stand at room temperature for one day to carry out a gelation reaction, and a homogeneous and transparent hydrogel was obtained. Next, the following operations were performed to measure the gel strength of these hydrogels. That is, a rod equipped with a metal ball with a diameter of 17.4 mm was connected to the autograph. A metal ball was sunk into the center of the hydrous gel in the beaker at a speed of 5 cm/min, stopped for 10 seconds at a penetration distance of 17.4 mm, and the stress applied to the rod at that time was measured. The results are shown in Table 1.

[Table] From Table 1, it can be seen that gel B is a fluid and soft hydrogel, and E and F are hydrogels with strong elasticity. In this way, hydrogels with various gel strengths can be prepared depending on the type of polyvalent amine and the amount added. Example 3 100 parts by weight of ethylene-maleic anhydride alternating copolymer ([η]=0.43) was reacted with 20 parts by weight of ammonia gas to prepare 120 parts by weight of ethylene-maleic anhydride alternating copolymer ammonia adduct. .
An aqueous solution of the ammonia adduct thus obtained was prepared with the composition shown in Table 2, and then heated at 40° C. for 2 hours to carry out a gelation reaction to produce a homogeneous and transparent hydrogel. This water-containing gel was immersed in a low-temperature constant temperature bath, and the freezing temperature was measured. The results are shown in Table 2.

[Table] As shown in Table 2, a hydrogel obtained by dissolving an ammonia adduct in a mixed solvent of polyhydric alcohol and water does not freeze even at low temperatures. The hydrogel containing this polyhydric alcohol was uniform and transparent and had excellent stability. Example 4 10 parts by weight of methyl vinyl ether-maleic anhydride alternating copolymer ([η] = 1.23), 6.4 parts by weight of 25% ammonia water and 183.6 parts by weight of water were stirred at room temperature to produce methyl vinyl ether-maleic anhydride alternating copolymer. An aqueous ammonia adduct solution of the copolymer was prepared. Add 100 parts by weight of this aqueous solution to fragrance (manufactured by Hasegawa Perfume Co., Ltd.)
No. 4744) were mixed and dispersed, 0.25 parts by weight of pentaethylenehexamine was added, and the mixture was sufficiently stirred and mixed. The aqueous solution thus obtained was placed in a cylindrical container with a diameter of 5 cm and heated at 50° C. for 30 minutes to produce a cylindrical pale yellow hydrogel with a diameter of 5 cm. This hydrogel piece was left at room temperature (15-25℃),
When the divergence effect was investigated, it was found that the divergence effect lasted for more than one month. This shows that this water-containing gel has the function of adjusting the rate of fragrance diffusion and is effective as a fragrance preservation material. Example 6 180 parts by weight of water was added to 20 parts by weight of the ammonia adduct of the isobutylene-maleic anhydride alternating copolymer used in Example 1 to prepare 200 parts by weight of an aqueous solution. On the other hand, polyvinyl alcohol (polymerization degree 1700)
completely saponified polyvinyl acetate) 10 parts by weight of water
10 parts by weight of the aqueous solution was prepared by adding 10 parts by weight, heating and dissolving at 90°C for 1 hour, and then cooling to room temperature. Two hydrogels having the compositions shown in Table 3 were prepared using the aqueous solution thus prepared and polyethyleneimine having an average degree of polymerization of 800 as a gelling agent. In addition,
The gelation reaction is carried out after uniformly mixing the compositions shown in Table 3.
A transparent hydrogel was obtained by heating in a constant temperature bath at 40°C for 40 minutes. These hydrogels had excellent gel strength.

[Table] A flat plate (area: 3 cm ² ) covered with cotton cloth was applied to the surface of the hydrous gel obtained in this way and was moved back and forth over a length of 5 cm while applying a pressure of 30 g/cm ² to create friction. When we measured the resistance to water, we found that the gel surface of the hydrogel with the composition P began to peel off little by little after 10 or so reciprocating movements, whereas the hydrogel with the composition Q that was used in combination with polyvinyl alcohol started to peel off after 100 cycles. Even with the above reciprocating motion, no peeling of the gel was observed. It has been found that good results can be obtained when polyvinyl alcohol is used in combination with hydrogels that require high surface friction strength. Example 7 100 parts by weight of the ammonia adduct of the isobutylene-maleic anhydride alternating copolymer used in Example 1 was mixed with 900 parts by weight of water to prepare 1000 parts by weight of a 10% aqueous solution. 1 part by weight of polyethyleneimine having a molecular weight of about 600 was added to this aqueous solution, which was then sealed in a soft polyvinyl chloride bag and allowed to stand at 40°C for 30 minutes to carry out a gelation reaction. The water-containing gel in this bag exhibits a flexible jelly-like appearance even at room temperature, and when the bag is left overnight at 0 to 5°C, a practically excellent cold bag with almost the same flexible jelly-like appearance as at room temperature is obtained. Ta. Furthermore, even when heated to 60 to 70°C, it exhibited almost the same jelly-like appearance, and was found to be useful as a heat-retaining bag for hot compresses, etc.

Claims (1)

[Claims] 1. A reaction product (a) obtained by reacting a copolymer of a vinyl compound or a vinylidene compound with maleic anhydride with ammonia, having the general formula H-(NH-CH ₂ -CH ₂ - ) _o NH ₂ (wherein n is an integer from 1 to 50) A mixture formed by mixing a polyvalent amine (b) and water (c) in a water-containing state is obtained by gelling it. water-containing gel.