JP3069982B2 - Polymer gel and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polymer gel used for a patch base such as a molded patch, an adhesive bandage, a bandage, a wound bandage and a supporter, and a method for producing the same. More specifically, a polymer gel containing a water-soluble polymer containing an unsaturated aliphatic carboxylic acid or a salt thereof as a monomer component as a main component of the base and having a significantly reduced production time as compared with the conventional method, and a production method thereof About the method.

[0002]

2. Description of the Related Art Heretofore, so-called molded patches containing a water-soluble polycarboxylic acid such as sodium polyacrylate or a salt thereof as a base component have been widely used for surgical treatment of arthralgia, myalgia and the like. As a method for producing these molded patches, conventionally, generally, a polycarboxylic acid and a salt thereof, a poorly water-soluble aluminum compound such as aluminum hydroxide, and an excipient such as kaolin and gelatin are mixed in the presence of water. A method of gelling by adjusting the pH to 4 to 7 using an organic acid has been used (for example, see JP-A-54-10).
Nos. 6598, 55-90517, 56-1891
No. 7, No. 59-25320, No. 59-93012,
No. 60-226808). This gelation reaction is considered to be due to the crosslinking between the carboxyl group in the polycarboxylic acid and the aluminum ion, and the gelation rate is the dissolution rate of the sparingly soluble aluminum compound, that is, the surface area and the dissolution product of the sparingly soluble aluminum compound, It is said that it depends on the pH of the solution and the dissolution-promoting action of the organic acid by chelation of aluminum (for example, Japanese Patent Publication No. Sho 61-4).
1926).

[0003] However, it is known that aluminum hydroxide, which is widely used as a poorly water-soluble aluminum compound, is increased in molecular weight by temporal aging (for example, Keihei Ueno, "Introductory Chelate Chemistry", p1
3) In the polymerized state, the dissolution rate is extremely slow even if the pH of the solution is lowered with an acid, and it takes several weeks for the composition to gel. Also, if the gelling mechanism is due to the metal crosslinking between the carboxylic acid and aluminum in the polymer, the excess amount of hydrogen ions is expected to work competitively with the aluminum ions. Not promoted,
In fact, below pH 3 only very low strength gels can be obtained. Further, when an organic acid is present in an excessive amount, the masking effect due to the formation of a chelate with aluminum becomes strong, and metal cross-linking with the polymer is inhibited.

[0004] Under such circumstances, in the conventional formulation of a patch, an inorganic excipient such as kaolin or a polymer excipient such as gelatin is blended as a means for improving the moldability of a low-strength gel base. Is used. According to the study by the present inventors, in the conventional patch formulation, these excipients most contribute to the moldability, and it takes several weeks for the gelation with only the poorly water-soluble aluminum compound and the organic acid alone. In short, it has been found that the strength of the obtained gel is low. However, even if these excipients are blended, the gelation takes several days, so that an increase in production costs due to product storage is inevitable, and the blending of excipients complicates the production process and simultaneously There is a drawback that increases the cost of raw materials.

Further, according to the findings of the present inventors, a copolymer having a low content of carboxylic acid (salt) groups, for example, an N-vinylacetamide / sodium acrylate copolymer having an acrylic acid monomer content of about 10 mol%. Alcohol-based polymers such as polymers and acrylamide / sodium acrylate copolymers hardly crosslink in the conventional method using an aluminum compound, but this is considered to be due to a decrease in the probability of the reaction between carboxylic acid and aluminum.

As a prior art, a method has been proposed in which a methoxyethylene / maleic anhydride copolymer is crosslinked with aluminum hydroxide and lactic acid in about one hour (JP-A-56-18917). There is no description on the composition ratio and crosslinkability, and it cannot be said that this technique is applicable to a copolymer having a carboxylic acid (salt) monomer component ratio of about 10% or less.

In the conventional method, sodium polyacrylate is dispersed in a polyhydric alcohol such as glycerin and then mixed with an aqueous dispersion of kaolin. Therefore, the polymer is kneaded almost uniformly while the polymer swells. Is possible, but
In the case of the above-mentioned alcoholic polymer, this method cannot be applied because the polymer itself swells with a polyhydric alcohol,
Even if it is blended, the kaolin particles aggregate, rather deteriorating the moldability. As described above, the conventional technique not only has a complicated formulation, but also has a limited polymer composition that can be applied, and further, a period of several days to several weeks to gel to an extent that sufficient cohesion is obtained. There was a problem that required.

Therefore, the present inventors have studied to develop a method that can gelate in a relatively short time without using an excipient such as kaolin. First, if the hydration of aluminum hydroxide controls the dissolution rate, and thus the gelation rate, as described in the section of the prior art, if the water-soluble aluminum compound is alkali-neutralized at the time of use, the olation proceeds. An experiment was conducted on the assumption that the compounding should be carried out in a state where it was not performed. As a result, when a water-soluble aluminum compound that has been alkali-neutralized at the time of use is used, even if the conventional method requires several weeks, even if the proportion of the carboxylic acid (salt) monomer component is about 10%, It has been found that it is possible to gel to a sufficient strength within 1-2 days.

However, even the above-mentioned method using a water-soluble aluminum compound which has been alkali-neutralized at the time of use has a problem that the gelation time is not short enough to be practically satisfactory. In other words, in order to solve the problem of product stock after the manufacture of the formulation, gelation is almost completed within tens of minutes after the application of the base material, ideally within a few minutes, considering the process and the productivity of the formulation. Need to be done.

Therefore, as one of the methods for shortening the gelation time after coating, a method in which gelation is advanced to some extent while kneading raw materials such as a polymer, a solvent, and an additive can be considered. For example, when an organic acid such as lactic acid, which is considered to have a weak chelating effect with aluminum, is used, the dissolution of aluminum hydroxide is promoted in combination with mechanical dispersion during kneading, and gelation proceeds. However, in this method, not only the kneading conditions need to be strictly controlled, but also the viscosity of the base significantly increases, so that the speed of the production line must be reduced in order to perform uniform film formation. It reduces productivity. Therefore, it is necessary to provide a method for shortening the gelation rate and, at the same time, facilitating the application by suppressing the viscosity at the time of kneading the raw materials.

As described above, the viscosity of the base before application is kept low, and after application, it is extremely short, preferably several minutes to
The technique of gelling in a few tens of minutes is very difficult with the prior art.

[0012]

Accordingly, an object of the present invention is to eliminate the problems of the prior art in the above-mentioned patch base,
To provide a polymer gel and a method for producing the polymer gel, which can keep the viscosity of a base before application low and facilitate application, and can gelate in a very short time after application, preferably several minutes to several tens of minutes. It is in.

[0013]

Means for Solving the Problems The present inventors have conducted intensive studies on the problems of the conventional method for producing a polymer gel, and as a result, have found that when a water-soluble aluminum compound is used as a poorly water-soluble aluminum compound, an alkali neutralized product is used. , And by using a specific hydroxycarboxylic acid or an acid anhydride thereof, and adding a heating operation step, the gelation at the time of kneading the base material hardly progresses, while the gelation time after application Can be shortened within several tens of minutes. Furthermore, they have found that the gelation time can be reduced to within several minutes by using infrared rays, particularly far infrared rays, or microwaves as a heat source of the heat treatment, and have completed the present invention.

That is, according to the present invention, a water-soluble polymer containing an unsaturated aliphatic carboxylic acid or a salt thereof as a monomer component, aluminum hydroxide prepared by alkali-neutralizing a water-soluble aluminum compound at the time of use, gluconic acid Glucono-δ-lactone, glycolic acid, glyceric acid, galacturonic acid, galactonic acid, one or two or more hydroxycarboxylic acids or acid anhydrides thereof selected from the group consisting of galactono-γ-lactone, and water are essential. A polymer gel obtained by gelling a mixture as a component, a water-soluble polymer having an unsaturated aliphatic carboxylic acid or a salt thereof as a monomer component, an alkali neutralized product of a water-soluble aluminum compound when used, gluconic acid, glucono- δ-lactone, glycolic acid, glyceric acid, galacturonic acid, galactonic acid, galactono A polymer obtained by heat-treating a mixture containing one or more hydroxycarboxylic acids or acid anhydrides thereof selected from the group consisting of -γ-lactones and acid anhydrides thereof, and water as essential components; The present invention provides a method for producing a gel, a method for producing a polymer gel in which the heat source of the heat treatment is infrared rays, far-infrared rays, or microwaves, and the above-described method in which the polymer gel is a patch base.

Hereinafter, the present invention will be described in more detail. The water-soluble polymer having an unsaturated aliphatic carboxylic acid or a salt thereof as a monomer component used in the present invention is, as a repeating unit thereof, acrylic acid, methacrylic acid, crotonic acid,
Maleic acid, maleic anhydride, fumaric acid, citraconic acid, itaconic acid, aconitic acid, 3-butenoic acid, 4-
Pentenic acid, ω-undecenoic acid, carboxyethyl acrylate, N-methacryl-α-amino acid, and a carboxyl group such as an alkali metal salt thereof or a salt thereof are not particularly limited, but preferably the carboxyl group or It is desirable to use a polymer containing the salt-containing monomer component in an amount of 1 mol% or more of the whole copolymer composition and capable of uniformly absorbing and swelling water at a concentration of 1% by weight or more.

As long as it satisfies this condition, either a homopolymer composed of the above-mentioned repeating unit alone or a copolymer partially containing the above-mentioned repeating unit can be used. The type of the partner monomer to be copolymerized is not particularly limited, and includes any of a random copolymer, a cross copolymer, a linear copolymer, and a partially crosslinked copolymer.

If the composition ratio of the carboxyl group-containing monomer component is less than 1 mol%, the amount of carboxyl groups involved in metal crosslinking is too small to obtain a gel having sufficient strength and cohesion. In addition, when the water affinity of the polymer is low and the water does not swell uniformly at a concentration of 1% by weight or more, it is not only difficult to uniformly knead it with other components, but also it is difficult to mix in the base. Since the swollen polymer particles remain or gelation partially proceeds, the moldability deteriorates.

Specific examples of the water-soluble polymer suitably used in the present invention include polyacrylic acid, polymethacrylic acid, carboxyvinyl polymer, acrylic acid / itaconic acid copolymer, and acrylic acid / maleic acid copolymer. Polymer, acrylic acid / maleic anhydride copolymer, acrylic acid / fumaric acid copolymer,

N-vinyl acetamide / acrylic acid copolymer, N-vinyl cetaceamide / methacrylic acid copolymer, N-vinyl acetamide / maleic acid copolymer, N
-Vinyl acetamide / fumaric acid copolymer, N-vinyl acetamide / itaconic acid copolymer, N-vinyl formamide / methacrylic acid copolymer, N-vinyl formamide / maleic acid copolymer, N-vinyl-N-methyl Acetamide / methacrylic acid copolymer,

Acrylamide / acrylic acid copolymer, N
-Methylol methacrylamide / maleic acid copolymer,
N, N-diisopropylacrylamide / maleic anhydride copolymer, N, N-dimethylaminopropylmethacrylamide / acrylic acid copolymer, N-vinyl-N, N-
Dimethylamine / itaconic acid copolymer, methyl vinyl ether / methacrylic acid copolymer, N-vinylpyrrolidone / acrylic acid copolymer, N-vinyl-3-methylpyrrolidone / fumaric acid copolymer,

Allyl chloride / acrylic acid copolymer, allyl alcohol / acrylic acid copolymer, N, N-diethylallylamine / crotonic acid copolymer, vinyl chloride / citraconic acid copolymer, vinyl acetate / acrylic acid copolymer Coalescence, acrylonitrile / methacrylic acid copolymer, allyl acetate /
Maleic acid copolymer, methyl vinyl ketone / itaconic acid copolymer,

A methyl acrylate / acrylic acid copolymer,
Ethyl methacrylate / itaconic acid copolymer, hydroxyethyl methacrylate / acrylic acid copolymer, hydroxypropyl methacrylate / methacrylic acid copolymer, diethylaminoethyl methacrylate / citraconic acid copolymer, diethylaminoethyl methacrylate / maleic anhydride copolymer Polymer, methoxy polyethylene glycol # 10
00 methacrylate / acrylic acid copolymer,

Styrene / methacrylic acid copolymer, vinylsulfonic acid / itaconic acid copolymer, allylic phosphoric acid / fumaric acid copolymer, 2-acrylamido-2-methylpropanesulfonic acid / acrylic acid copolymer, N-vinyl Acetamide / methyl acrylate / methacrylic acid copolymer, N
-Vinyl acetamide / hydroxyethyl methacrylate / acrylic acid copolymer, N-vinyl acetamide / acrylamide / itaconic acid copolymer,

N-vinylacetamide / acrylonitrile / fumaric acid copolymer, N-vinylacetamide / N-
Methylol acrylamide / acrylic acid copolymer, N-
Vinylacetamide / 2-acrylamide-2-methylpropanesulfonic acid / maleic acid copolymer, N-vinylacetamide / methoxypolyethylene glycol # 10
00 methacrylate / acrylic acid copolymer, N-vinylacetamide / acrylic acid / N, N-methylenebis-N
-Vinylcetamide copolymer, N-vinylacetamide / methacrylic acid / N, N-butylenebis-N-vinylacetamide copolymer,

N-vinylacetamide / acrylic acid /
N, N '-(diacetyl) -N, N'-(divinyl)-
1,4-bis (aminomethyl) cyclohexane copolymer, N-vinylacetamide / itaconic acid / N, N-methylenebisacrylamide, N-vinylacetamide /
Acrylic acid / ethylene glycol dimethacrylate copolymers and salts obtained by partially or completely neutralizing them with an alkali metal such as sodium or potassium, or an alkaline earth metal such as calcium or barium are exemplified.

Next, the alkali-neutralized product of the water-soluble aluminum compound used in the present invention includes aluminum chloride,
It is an aluminum hydroxide suspension obtained by neutralizing a water-soluble aluminum compound such as aluminum sulfate, aluminum nitrate, aluminum potassium sulfate and aluminum ammonium sulfate with an alkali such as sodium hydroxide and potassium hydroxide at the time of use.

Here, "use time" means to prepare and use it within the day. Specifically, it is preferably used within 24 hours, preferably within 12 hours after preparation and within as short a time as possible.

According to the measurement by the present inventors, the average particle size of the aluminum hydroxide particles immediately after neutralization is as large as about 20 μm, the bulk density is low, and the dissolution rate is high. The particle size decreases and changes to a more dense and poorly water-soluble structure. For example, when stored at room temperature for 2 days, the average particle size decreases to about 16 μm, and the gelling ability decreases. The average particle size of a commercially available aluminum hydroxide reagent is about several μm, and even if it is used, the effect of the present invention is hardly obtained.

The amount of the aluminum hydroxide suspension is determined mainly by the type and amount of the hydroxycarboxylic acid or acid anhydride described below to be compounded. That is, a carboxyl group in a polymer and a hydroxycarboxylic acid (including a hydrolysis product of an acid anhydride) in a base material
Perform interactions such as chelate formation with aluminum ions, and it is presumed that the two are in competition. Therefore, if the interaction of hydroxycarboxylic acid is strong, the masking action of aluminum ions increases, and it is necessary to mix a larger amount of aluminum hydroxide suspension.

In general, in the hydroxycarboxylic acid or acid anhydride described below, the molar ratio of hydroxycarboxylic acid to aluminum in terms of aluminum is 0.5 to 2.0, and hydroxycarboxylic acid (glucone) having relatively weak interaction with aluminum ions is used. When acid, glucono-δ-lactone, glycolic acid or glyceric acid) is used, the molar ratio in terms of aluminum is preferably in the range of 0.5 to 1.0, and hydroxycarboxylic acid having relatively weak interaction with aluminum ions is preferred. When (galacturonic acid, galactonic acid or galactono-γ-lactone) is used, the molar ratio is preferably in the range of 1.0 to 2.0. Two or more of these hydroxycarboxylic acids or acid anhydrides thereof may be used in combination. In such a case, the amount of the aluminum hydroxide suspension may be adjusted according to the compounding ratio. If the amount of the aluminum hydroxide suspension is less than the above range, the strength of the gelled base and the cohesive strength are reduced, and if it exceeds this range, the cohesive strength is too strong and the adhesiveness to the skin is reduced. In addition, aluminum hydroxide particles aggregate and formability deteriorates.

The blending amount of the aluminum suspension is also affected by the carboxylic acid introduction rate of the polymer, but it is considered that a part of the carboxyl group in the polymer is involved in the metal crosslinking, Even if the rate changes, it is not necessary to greatly increase or decrease the crosslinking point. Therefore, it is only necessary to finely adjust the compounding amount according to the hydroxycarboxylic acid or its anhydride used. Further, since the amount of the aluminum hydroxide suspension affects the strength or cohesion of the gel after molding, it may be finely adjusted appropriately according to the desired gel strength.

In the present invention, water swells the polymer and is required as a solvent for hydroxycarboxylic acid or its acid anhydride and aluminum, and as a heating medium for heating, and at least 50% by weight or more of the whole solvent. It is desirable to be blended. As the solvent, besides this, it is possible to add those that are blended with a normal patch base, for example, for the purpose of improving the water retention of the base and the solubility of the pharmaceutically active ingredient, and percutaneous absorption, Polyhydric alcohols such as glycerin, 1,3-butanediol, propylene glycol, polyethylene glycol and polypropylene glycol,
One or more of lower alcohols such as ethanol and isopropanol can be used. These amounts are appropriately selected depending on the purpose and effect of using the solvent, the swelling properties of the polymer, the solubility of hydroxycarboxylic acid and aluminum, and the properties of the heat medium used in the heating step.

Next, in the present invention, specific hydroxycarboxylic acids or acid anhydrides thereof, that is, gluconic acid, glucono-δ-lactone, glycolic acid, glyceric acid, galacturonic acid, galactonic acid, galactono-
One or more hydroxycarboxylic acids or acid anhydrides selected from γ-lactone or anhydrides are blended.

As described above, it is said that hydroxycarboxylic acid promotes dissolution of a poorly water-soluble aluminum compound by lowering the pH of the base material and simultaneously forming a chelate with aluminum ions. However, in the case of hydroxycarboxylic acids having too high a chelate-forming ability, for example, polybasic acids such as tartaric acid and citric acid, the gelling is inhibited due to the strong masking action of aluminum ions.
Even if an excessive amount of the aluminum hydroxide suspension is added to avoid this, not only does a large amount of suspended particles agglomerate, deteriorating the moldability, but also the gel can be heated in a short time even when heated. It cannot be done. On the other hand, when an acid such as lactic acid, which has a weak chelate-generating ability, is used, gelation by heating is quick, but gelation proceeds during kneading of the base material, and the Film forming property or productivity decreases.

As described above, the effects of the heating method of the present invention can be obtained only when the specific hydroxycarboxylic acid or its acid anhydride is blended as far as the present inventors know. Incidentally, as a result of a detailed study by the present inventors, the effect of hydroxycarboxylic acid is not necessarily correlated with the ability to form a chelate with aluminum, and it is difficult to easily infer from the chelate stability constant and the molecular structure. In addition, in addition to the above-mentioned lactic acid, tartaric acid, citric acid, and acids other than those specified above, such as glucuronic acid, the effects of the present invention cannot be achieved.

The amount of these hydroxycarboxylic acids or their anhydrides varies depending on the strength of the hydroxycarboxylic acid as an acid, the degree of interaction with aluminum, and the like. The compounding amount is generally from 0.1 to 4.0, expressed in terms of% by weight based on the total amount of the base material.

Hydroxycarboxylic acids having a relatively large amount include gluconic acid, glucono δ-lactone, galacturonic acid, galactonic acid and galactono-γ-lactone. The compounding amount is 0.5 to 4.0, and the preferred range for each is 0.5 to 4.0. That is, 0.9 to 3.6 for gluconic acid and glucono δ-lactone and 0.9 for galacturonic acid.
3.63.6, and 0.8-3.4 for galactonic acid and galactono-γ-lactone.

On the other hand, glycolic acid and glyceric acid are listed as hydroxycarboxylic acids having a relatively small amount of compounding, and the compounding amount is 0.1 to 2.0, and the preferable range of each is 0.3 to 1.5 for glycolic acid and glycerin for glycerin. For acids it is 0.5-2.0.

If the amount is less than the above range, the dissolution rate of aluminum hydroxide is low, so that the gelation time becomes too long. Conversely, if the amount exceeds this range, the pH of the base material becomes too low, and the masking action on aluminum increases. Therefore, the moldability deteriorates.

As described above, the present invention provides an aqueous dispersion of an unsaturated aliphatic carboxylic acid and a salt thereof, which is prepared by neutralizing a water-soluble polymer before use with an aluminum hydroxide suspension and a specific hydroxycarboxylic acid or a specific hydroxycarboxylic acid. It is characterized in that an acid anhydride is blended and heat treatment is performed.

In the method of the present invention, the kneaded base mixture is applied to a support or a release body to a predetermined thickness by a known method, and then subjected to a heat treatment. As the heating method,
In principle, any conventionally known method, such as a method in which air is used as a heat medium in a thermostatic oven or a hot-air dryer, or a method in which heat is directly conducted to a base such as a hot roll, infrared rays, or microwave irradiation, etc. Although it is applicable, in order to achieve the intended purpose of shortening the gelation speed, among these, the base material is heated uniformly and the electromagnetic waves such as infrared rays, far infrared rays, Irradiation has been found to exhibit excellent effects. These electromagnetic wave irradiation methods include heating fields such as thermal heaters, medical and health care fields such as thermotherapy and infrared saunas, food processing fields such as drying, thawing and heating of foods, and agriculture, forestry and fisheries such as heating greenhouses and livestock barns. Conventionally used methods in the field, such as plastic molding, and industrial fields such as drying of paints and papers, can be used (for example,
Hiroshima Takashima, "Utilization technology of far infrared rays and its applications and examples" p1
42 etc.).

The heating condition is such that the temperature of the base material after coating is 6
Conditions maintained at 0 to 90 ° C, preferably 70 to 80 ° C, are desirable. There is no limitation on the type of heat source or heating method within this range, and when it comes to irradiation of electromagnetic waves such as far infrared rays and microwaves, the type, material, radiant heat and wavelength pattern of the electromagnetic wave radiator, and the position of the radiator are Can be set arbitrarily. If the temperature of the base is lower than 60 ° C., the gelation time becomes too long, and if the temperature exceeds 90 ° C., the moisture evaporates and the base is deformed or bubbles are generated, which is not preferable. The heating time varies depending on the temperature. For example, in the case of hot air heating, 30 to 60 at 60 ° C.
Minutes, 90 ° C for 15 to 30 minutes, and far infrared or microwave irradiation at 60 ° C for 5 to 10 minutes, 90 ° C
In this case, it is almost gelled by irradiation for about 2 minutes.

[0043]

[Action] Although the mechanism of action that can produce a polymer gel in a short time is not clear, it is difficult to mix a water-soluble aluminum salt with an alkali-neutralized product and a specific hydroxycarboxylic acid, and then add a heat treatment. , (1) The dissolution rate of aluminum hydroxide is high because the degree of aluminum hydroxide is small, and (2) The interaction between hydroxycarboxylic acid and aluminum ions is moderate. The viscosity of the base does not increase and the gelation after heating is accelerated. (3) The heat treatment promotes the dissolution of aluminum hydroxide. In particular, (far) infrared rays and microwaves enter the base. The base containing a water-soluble polymer of an aliphatic carboxylic acid or a salt thereof can be used for several minutes to several
It is considered that gelation became possible in 0 minutes.

[0044]

[Use] The polymer gel according to the present invention is used for various purposes. The largest fields of use include adhesive bases such as molded cataplasms, adhesive bandages, adhesive plasters, wound plasters, and supporters, as well as fragrances, cosmetic packs, and other daily necessities. In the case of a patch base, in addition to the essential components of the polymer gel of the present invention, a medicinal component or an absorption aid can be blended for the purpose of treating human or animal diseases, and it can be tailored to each application. Optional additives can be added. In the present invention, the use of inorganic or polymeric excipients is not necessarily required as described above, but it is, of course, optional to mix them according to the use and purpose, thereby reducing the effects of the present invention. Not something.

[0045]

According to the present invention, when a water-soluble aluminum compound is used as a poorly water-soluble aluminum compound, an alkali neutralized product is used, and as an organic acid that forms a chelate with aluminum to increase the solubility of the aluminum compound, By using a hydroxycarboxylic acid or an acid anhydride thereof and adding a heating operation step, gelation when kneading the base material hardly progresses, and application to a substrate such as a patch is easy, and application is easy. The subsequent gelation time can be reduced to within several tens of minutes, and the gelation time can be reduced to within several minutes by using infrared rays, particularly far-infrared rays, or microwaves as a heat source for the heat treatment. A polymer gel can be produced in a much shorter time than the conventional method that required days.

The polymer gel obtained by the method of the present invention is excellent in properties such as self-retaining property, water retention, heat stability, water absorption and moisture release required as a patch base and the like. The production method of the invention is extremely useful industrially.

[0047]

EXAMPLES The present invention will be described in more detail below with reference to Reference Examples, Examples and Comparative Examples, but it goes without saying that the technical scope of the present invention is not limited to the following contents.

Reference Examples 1 to 14: Production of Polymers The polymers used in Examples of base production described below were produced by the following methods. A 1-liter four-neck separable flask was equipped with a stir bar, a thermometer, and a nitrogen inlet tube, and an aqueous solution in which 100 g of the raw material monomer mixture shown in Table 1 was dissolved in 280 g of deionized water was charged. After removing dissolved oxygen by introducing nitrogen gas, the temperature was raised to 30 ° C., and 20 g of a 5% aqueous solution of 2,2′-azobis-2-amidinopropane dihydrochloride was added as a polymerization initiator. ° C
Was controlled for 10 hours. The obtained polymer is poured into a mixed solution of acetone / water, filtered, dehydrated,
Vacuum drying was performed to obtain a dried polymer.

1 g of the dried polymer is dissolved in distilled water and
0 ml (0.2% aqueous solution), heated to 30 ° C,
The viscosity was measured using a Brookfield viscometer at a rotation speed of 20 rpm. The measurement results of the viscosity are shown in Table 1. The symbols shown in Table 1 are as follows.

AA; acrylic acid AA-Na; sodium acrylate FA; MA fumaric acid; maleic acid NVA; N-vinylacetamide AN; acrylonitrile HEMA; hydroxyethyl methacrylate N-MAM; N-methylol acrylamide DAM; dimethylaminoethyl methacrylate AMPS; 2-acrylamido-2-methylpropanesulfonic acid CBN; N, N '-(diacetyl) -N, N'-(divinyl) -1,4-bis (aminomethyl) cyclohexane

[0051]

[Table 1]

Examples 1 to 11: Production Examples of Polymer Gel Base materials were blended according to the formulation shown in Table 2. Distilled water 2.7
g and 1.0 g of glycerin were mixed or dissolved with a predetermined amount of each hydroxycarboxylic acid.
0.25 g of the polymer prepared in 14 was swollen at room temperature. When glucono-δ-lactone or galactono-γ-lactone was used as the hydroxycarboxylic acid, the mixture was added to the mixed solvent and left overnight at room temperature to mix the polymer.

Separately, a predetermined amount of aluminum chloride is dissolved in about 3 ml of distilled water, and the pH is adjusted with a 1N aqueous sodium hydroxide solution.
The resulting suspension was adjusted to a range of 6.9 to 7.2, and the resulting suspension was made up to 10 ml with distilled water to prepare an aluminum hydroxide suspension. Next, the polymer swelling liquid was transferred to a mortar, and kneaded for 30 minutes while the aluminum hydroxide suspension was added dropwise (total amount: 1.2 ml). This kneaded material was filled in a glass vial having a capacity of 5 ml, and heated in a hot air thermostat under predetermined conditions to gel.

[0054]

[Table 2]

[0055]

[Table 3]

The symbols shown in Table 2 are as follows. GluA; gluconic acid GluL; glucono-δ-lactone GlcA; glycolic acid GlyA; glyceric acid GTA; galacturonic acid GalA; galactonic acid GalL; galactono-γ-lactone α-HBA; α-hydroxybutyric acid α-HIBA; Butyric acid β-HPrA; β-hydroxypropionic acid

Β-HBA; β-hydroxybutyric acid β-HIVA; β-hydroxyisovalerate HPA; hydroxypivalic acid LacA; lactate TartA; tartaric acid CitA; citric acid HPA; hydroxypivalic acid LacA; lactate TartA; ;citric acid

Comparative Examples 1 to 9 In Example 5, the hydroxycarboxylic acid was changed to glucono-
A polymer gel was prepared in the same manner as in Example 5, except that δ-lactone was changed to those shown in Table 2.

Comparative Examples 10 and 11 The same procedures as in Example 5 were carried out except that the heating temperature was changed to 40 ° C. (Comparative Example 10), or the mixture was left at room temperature without performing the heating operation (Comparative Example 11). A polymer gel was prepared by the operation described above.

Comparative Example 12 The procedure of Example 5 was repeated, except that the aluminum hydroxide suspension neutralized before use was replaced with the same amount of a commercially available aluminum hydroxide reagent suspension in terms of aluminum. A polymer gel was prepared in the same manner as in Example 5.

Examples 12 to 31 Base materials were blended in the same manner as in Example 5 according to the formulation shown in Table 4 below. A film having a thickness of about 0.5 mm is formed on a plastic plate on which a thermocouple is inserted and mounted on the kneaded product after the aluminum hydroxide suspension is blended, and a PET film having a thickness of 50 μm is laminated thereon. Was irradiated under a predetermined condition to cause gelation.

Comparative Examples 13 to 21 Polymer gels were prepared in the same manner as in Example 15 except that the hydroxycarboxylic acid was changed from glucono-δ-lactone to those shown in Table 4. Prepared.

Comparative Example 22 In Example 15, instead of irradiation with far-infrared rays,
A polymer gel was prepared in the same manner as in Example 15 except that the polymer gel was left for 0 hours.

Comparative Example 23 The procedure of Example 15 was repeated, except that the same amount of a suspension of a commercially available aluminum hydroxide reagent as an aluminum equivalent was used in place of the aluminum hydroxide suspension neutralized before use.
A polymer gel was prepared in the same manner as in Example 15.

Evaluation Test Example 1 Gelation State of Polymer Gel The gelation state of the polymer gels prepared in Examples 1 to 11 and Comparative Examples 1 to 12 over time was evaluated as follows. At a predetermined time after the heating, the vial was taken out of the thermostat and air-cooled until the temperature reached approximately room temperature. An insertion needle having a weight of 0.94 g was passed through a glass tube having an inner diameter of 3 mm which was vertically fixed on a scale plate, and was held in a state where the tip of the insertion needle was in contact with the gel surface. At the same time as the timer was activated, the insertion needle was dropped from the vertical direction, and the distance of the insertion needle moved for 60 seconds was evaluated as the penetration. The upper limit value of the penetration in this test method (the value when the tip of the insertion needle is in contact with the bottom of the vial) is 15 mm. Table 3 shows the evaluation test results.

[0066]

[Table 4]

[0067]

[Table 5]

As is clear from the evaluation test results of Examples 1 to 11, in the production method according to the present invention, each of the production methods was 30 to 60.
The gelation was almost completed within minutes. On the other hand, when a hydroxycarboxylic acid other than the present invention was used (Comparative Examples 1 to 9)
Was not preferred because the gelation rate was slow or gelation proceeded during kneading of the base material (Comparative Example 7). Further, when the heating temperature was lowered to 40 ° C. (Comparative Example 10) or when the room temperature was left instead of the heating operation (Comparative Example 11), the gelation was delayed depending on the temperature decrease. Furthermore, when a suspension of a commercially available aluminum hydroxide reagent was used in place of the aluminum hydroxide suspension neutralized before use (Comparative Example 12), almost no gelation was observed even after 7 days. Was.

Evaluation Test Example 2: Gelation State of Polymer Gel The gelation states of the polymer gels prepared in Examples 12 to 31 and Comparative Examples 13 to 23 were evaluated by finger touch and appearance observation. Table 4 shows the evaluation results. The symbols in Table 4 have the same meanings as those in Table 2.

[0070]

[Table 6]

[0071]

[Table 7]

As is clear from the evaluation test results of Examples 12 to 31, all of the production methods according to the present invention showed good gelation states. On the other hand, when a hydroxycarboxylic acid other than the present invention was used (Comparative Examples 13 to 21), gelation was insufficient or gelation proceeded during kneading of the base material, which was not preferable. In addition, the gelation was poor when left at room temperature for 10 hours instead of irradiation with far infrared rays (Comparative Example 22). Further, when a suspension of a commercially available aluminum hydroxide reagent was used instead of the aluminum hydroxide suspension neutralized at the time of use (Comparative Example 23), gelation hardly occurred despite irradiation with far infrared rays. Not observed.

From the results shown in Table 4, according to the production method of the present invention, regardless of the degree of carboxylic acid introduction, a polymer gel containing a water-soluble polymer of an aliphatic carboxylic acid or a salt thereof as a constituent was obtained. It can be seen that it can be obtained in a very short time.

Continuation of front page (56) References JP-A-63-156717 (JP, A) JP-A-63-270741 (JP, A) JP-A-62-262736 (JP, A) JP-A-64-56707 (JP) , A) (58) Field surveyed (Int. Cl. ⁷ , DB name) C08F 8/44

Claims (4)

(57) [Claims] 1. A water-soluble polymer containing an unsaturated aliphatic carboxylic acid or a salt thereof as a monomer component, aluminum hydroxide, gluconic acid, glucono-δ-lactone prepared by alkali-neutralizing a water-soluble aluminum compound at the time of use. A mixture comprising, as essential components, one or more hydroxycarboxylic acids or acid anhydrides thereof selected from the group consisting of glycolic acid, glyceric acid, galacturonic acid, galactonic acid, and galactono-γ-lactone; Polymer gel formed 2. A water-soluble polymer containing an unsaturated aliphatic carboxylic acid or a salt thereof as a monomer component, an alkali-neutralized product when using a water-soluble aluminum compound, gluconic acid, glucono-δ-lactone, glycolic acid, glyceric acid. A mixture containing one or two or more hydroxycarboxylic acids or acid anhydrides thereof selected from the group consisting of galacturonic acid, galactonic acid, and galactono-γ-lactone, and water as an essential component; A method for producing a polymer gel, comprising: 3. The method for producing a polymer gel according to claim 2, wherein the heat source of the heat treatment is infrared rays, far infrared rays or microwaves. 4. The method according to claim 2, wherein the polymer gel is a patch base.