JP2012107120A - Adhesive gel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide hydrogel that suitably attaches to a surface of a living body by maintaining adhesion even when a water content is decreased and that is released without giving a stimulus on skin by maintaining flexibility.SOLUTION: The adhesive gel containing polyhydric alcohol and water in a matrix of a hydrophilic polymer and an acrylamide-based polymer is provided. The polyhydric alcohol and the water and the hydrophilic polymer and the acrylamide-based polymer plasticized by the polyhydric alcohol and the water exhibit wet adhesion when water is contained, and the adhesion is maintained due to wettability of the polyhydric alcohol and intermolecular interaction of the acrylamide-based polymer even when drying. In the adhesive gel, the hydrophilic polymer preferably includes polyvinyl alcohol, especially ether-modified polyvinyl alcohol, and the acrylamide-based polymer preferably includes an N-vinyl acetamide-sodium acrylate copolymer.

Description

  The present invention relates to an adhesive gel. More specifically, the present invention relates to a hydrogel that can be suitably applied to the surface of a living body while maintaining adhesiveness even when the water content is reduced, and that can be peeled without causing irritation to the skin while maintaining flexibility.

  Conventionally, hydrogel is known as an adhesive composition. Hydrogel has high affinity for water and has water absorption ability. For this reason, hydrogels do not repel water like oil-based rubber adhesives, and sweat does not accumulate between the skin and the adhesive even when applied to the surface of a living body for a long time. Less likely to cause skin maceration. In addition, even when sweating is high or the surface of a living body is wet, the hydrogel absorbs sweat and moisture to prevent a decrease in adhesive strength.

  Further, since hydrogel contains a large amount of moisture, it has cooling characteristics due to the latent heat of vaporization of water. Therefore, the hydrogel is affixed to the heat generating part and can be efficiently cooled for a long time.

  Furthermore, since hydrogel is excellent in wettability to a to-be-adhered surface, it is hard to give skin irritation | stimulation when peeling from a biological surface. Therefore, hydrogel can be used even for patients with weak skin tissue.

  On the other hand, the hydrogel exhibits a strong adhesive force with respect to a highly hydrophilic material, but exhibits a releasability rather than an adhesive with an oily material. Since sebum is usually present on the skin surface, there is a limit to increasing the adhesive strength of hydrogel having high hydrophilicity. Therefore, in order to prevent the application position from being shifted or peeled when applied to the surface of a living body, the hydrogel is fixed with another adhesive or the like.

  As a method for solving this problem, a gel adhesive composition comprising a crosslinked water-soluble polymer, water, a humectant, an amphiphilic polymer and a water-insoluble polymer has been reported (see Patent Document 1). As a method of adding the hydrophobic polymer to the hydrophilic polymer, a method of emulsifying and dispersing the hydrophobic polymer is generally used. In the hydrogel prepared by such a method, the adhesive strength can be improved without impairing the inherent low irritation and conductivity properties of the hydrogel.

JP 2002-136687 A

  When conventional hydrogel loses moisture in the gel, the wettability to the adherend surface decreases and the adhesive strength is lost, and it hardens and the followability to the adherend surface decreases. May peel from the surface of the living body, or may cause skin irritation at the time of peeling.

  Therefore, the present invention provides a hydrogel that can be applied to the surface of a living body while maintaining its adhesiveness even when the water content is reduced, and can be peeled without causing irritation to the skin while maintaining flexibility. The main purpose.

In order to solve the above problems, the present invention provides an adhesive gel containing a polyhydric alcohol and water in a matrix of a hydrophilic polymer and an acrylamide polymer, the hydrophilic polymer and the acrylamide polymer, The adhesive gel has a weight ratio of 1: 1 to 1:10, and a weight ratio of polyhydric alcohol, hydrophilic polymer and acrylamide polymer of 2: 1 to 6: 1. To do. In this adhesive gel, the polyhydric alcohol and water, the hydrophilic polymer and the acrylamide polymer plasticized by these when wet, exhibit wet adhesion, and even when dried, the wetness of the polyhydric alcohol Tackiness is maintained by the intermolecular interaction of acrylamide polymers.
In this adhesive gel, the hydrophilic polymer preferably contains polyvinyl alcohol. The polyvinyl alcohol is preferably ether-modified polyvinyl alcohol, and more preferably ether-modified polyvinyl alcohol having a linear or branched alkyl group having 6 to 22 carbon atoms as a substituent. The acrylamide polymer preferably contains an N-vinylacetamide-sodium acrylate copolymer. By forming hydrogen bonds using polyhydric alcohol and water-compatible polyvinyl alcohol, ether-modified polyvinyl alcohol, and N-vinylacetamide-sodium acrylate copolymer, the cohesive strength of the gel is increased, Polyhydric alcohol and water can be included in the gel. This adhesive gel can contain 30 to 70% by weight of water when it contains water.
Moreover, this adhesive gel can further contain polyvinylpyrrolidone as the hydrophilic polymer. In this case, it is preferable that the weight ratio of polyvinylpyrrolidone and N-vinylacetamide-sodium acrylate copolymer is 1: 100 to 1: 1.

  According to the present invention, even when the water content is reduced, a hydrogel that can be suitably applied to the surface of a living body while maintaining adhesiveness and that can be peeled without irritating the skin while maintaining flexibility is provided.

Hereinafter, preferred embodiments for carrying out the present invention will be described. In addition, embodiment described below shows an example of typical embodiment of this invention, and, thereby, the range of this invention is not interpreted narrowly. The description will be made in the following order.

1. 1. Adhesive gel 2. hydrophilic polymer 3. Acrylamide polymer 4. Polyhydric alcohol Mixing ratio 6. Method for producing adhesive gel

1. Adhesive Gel The adhesive gel according to the present invention contains a polyhydric alcohol and water in a matrix of a hydrophilic polymer and an acrylamide polymer. In this adhesive gel, it is considered that a hydrophilic polymer enters the polymer of the acrylamide polymer to form a matrix.

  In the pressure-sensitive adhesive gel according to the present invention, the polyhydric alcohol and water, the hydrophilic polymer and the acrylamide polymer plasticized by these when wet, exhibit wet adhesion, and even when dried, the polyhydric alcohol The adhesiveness is maintained by the wettability of the acrylamide and the intermolecular interaction of the acrylamide polymer. Therefore, even if the water content is reduced, the adhesiveness can be maintained and the film can be suitably applied to the surface of the living body.

  That is, when water is contained, polyhydric alcohol and water, and hydrophilic polymer and acrylamide polymer plasticized by these penetrate into the fine irregularities of the adherend surface, increasing the contact area, and excellent wet adhesion Demonstrate sex. Moreover, when drying, in addition to the wettability of polyhydric alcohol, the adhesive force with high intermolecular interaction property by the amide group of acrylamide polymer is brought about.

2. Hydrophilic polymer The hydrophilic polymer used in the adhesive gel according to the present invention also functions to maintain the gel strength when containing water. Examples of the hydrophilic polymer include polyvinyl alcohol, polyvinyl pyrrolidone, polyacrylic acid, polyacrylic acid Na, carboxymethyl cellulose Na, hydroxyethyl cellulose, hydroxypropyl cell source, sodium alginate, dextran, and the like. In particular, polyvinyl alcohol (hereinafter abbreviated as “PVA”) or polyvinyl pyrrolidone (hereinafter abbreviated as “PVP”) may be added to the hydrophilic polymer.

  A functional group may be added and introduced into the side chain and / or terminal of the hydrophilic polymer chain. As the functional group, a functional group having reactivity involved in crosslinking between hydrophilic polymers, or a functional group for controlling physical properties of the hydrophilic polymer can be added. It is preferable that both a functional group having reactivity and a functional group for controlling physical properties are added to the hydrophilic polymer, but at least a functional group for controlling physical properties may be introduced. .

  Examples of the functional group having reactivity include, but are not limited to, a hydroxyl group, a carboxyl group, an amino group, a ketone group, and an imide group. The functional group may be multifunctional as required. For example, when a ketone group is introduced into PVA as a functional group by diacetone acrylamide, the amount of diacetone acrylamide introduced is 2 to 4 mol%, preferably 3 to 4 mol%.

  Examples of the functional group for controlling physical properties include, but are not limited to, an ether bond and an ester bond. Here, the substituent added to or introduced into the ether bond or ester bond is not particularly limited and can be appropriately changed. However, a linear or branched alkyl group is preferable. 6-22 are preferable, as for carbon number of an alkyl group, 10-22 are more preferable, and 15-22 are more preferable. Moreover, when introduce | transducing a substituent into PVA, the introduction amount of a substituent shall be 0.1-15 mol%, Preferably it is 0.5-10 mol%.

  The hydrophilic polymer is preferably a PVA having a reactive functional group in the side chain and a functional group for controlling physical properties at the terminal. In this case, the reactive functional group is preferably a ketone group. The functional group for controlling physical properties is preferably an ether bond or an ester bond, and has a C6-C22, particularly preferably a C15-C22 linear or branched alkyl group as a substituent. Is preferred.

  In the present specification, polyvinyl alcohol in which a substituent such as an alkyl group is ether-bonded to the end of the molecular chain of polyvinyl alcohol or in the molecular chain is referred to as “ether-modified polyvinyl alcohol”.

  In the adhesive gel according to the present invention, the cohesive force of the gel is increased by forming hydrogen bonds using PVA or ether-modified PVA excellent in compatibility with polyhydric alcohol and water, and a large amount of polyhydric alcohol and water are gelled. Can be included inside. In particular, by using an ether-modified PVA having a C6-22 linear or branched alkyl group as a substituent, the cohesiveness of the gel can be further enhanced by the entanglement of the alkyl groups, so that a large amount of polyvalent Alcohol and water can be retained in the gel.

3. Acrylamide-based polymer The acrylamide-based polymer used for the adhesive gel according to the present invention also functions to maintain adhesiveness during drying. The acrylamide polymer can be a homopolymer of N-vinylacetamide or a copolymer with a monomer copolymerizable therewith. The acrylamide polymer is preferably a copolymer of N-vinylacetamide and one or more ethylenic monomers.

  Specific examples of the ethylenic monomer include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (Meth) acrylate, octyl (meth) acrylate, vinyl acetate, vinyl propionate, vinyl methyl ether, vinyl ethyl ether, hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, methoxyethyl (meth) acrylate, ethoxy Examples include ethyl (meth) acrylate, propylethyl (meth) acrylate, butoxyethyl (meth) acrylate, (meth) acrylic acid, sodium (meth) acrylate, and potassium (meth) acrylate. These ethylenic monomers can be used alone or in combination of two or more thereof.

  The acrylamide polymer is particularly preferably an N-vinylacetamide-sodium acrylate copolymer (hereinafter abbreviated as “PNVA-PAS”).

  By forming hydrogen bonds using PNVA-PAS, which is excellent in compatibility with polyhydric alcohol and water, the cohesive strength of the gel can be increased, and a large amount of polyhydric alcohol and water can be encapsulated in the gel. Furthermore, the adhesion to the adherend can be enhanced by the intermolecular interaction of the acrylamide polymer.

  Acrylamide polymers do not have functional groups. For example, PNVA-PAS is a copolymer (block copolymer) of N-vinylacetamide and sodium acrylate, and the sodium acrylate moiety serves as a crosslinkable reactive group. Since it works, it can be polymerized by metal crosslinking.

  For metal cross-linking, polyvalent metal salts, polyvalent metal hydroxides, polyvalent metal oxides, etc. are used. For example, aluminum chloride, potassium light vane, ammonium light vane, aluminum nitrate, aluminum sulfate, aluminum glycinate, EDTA -Aluminum, aluminum oxide, magnesium chloride, aluminum hydroxide / sodium bicarbonate coprecipitate (for example, "Kumlite" manufactured by Kyowa Chemical Industry Co., Ltd.), aluminum metasilicate, synthetic aluminum silicate, aluminum stearate, aluminum alane Toynate, synthetic hydrotalcite (for example, “Alkamak”, “Alkamizer”, “Kyoward”, etc., manufactured by Kyowa Chemical Industry Co., Ltd.) ), Aluminum hydroxide (eg, Kyowaso) "Dry aluminum hydroxide gel S-100" manufactured by Kogyo Co., Ltd.), aluminum acetate, dihydroxyaluminum aminoacetate (eg "Glycinal" manufactured by Kyowa Chemical Industry Co., Ltd.), kaolin, synthetic hydrotalcite, metasilicic acid Examples thereof include magnesium aluminate (for example, “Neusilin” manufactured by Fuji Chemical Industry Co., Ltd.), magnesium aluminate silicate, calcium hydroxide, calcium carbonate and the like. Among these, an aluminum compound and dry aluminum hydroxide gel are particularly preferable. The polyvalent metal salt, polyvalent metal hydroxide, polyvalent metal oxide and the like may be water-soluble or sparingly soluble, and one or more kinds may be used. .

4). Polyhydric alcohol In the adhesive gel according to the present invention, polyhydric alcohol is used as a plasticizer, and includes polyhydric alcohol and polyhydric alcohol derivatives which are derivatives thereof. Examples of the polyhydric alcohol include glycerin, polyglycerin (diglycerin, triglycerin, tetraglycerin, etc.), ethylene glycol, propylene glycol, polyethylene glycol (PEG600, etc.), diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, 1 , 5-pentanediol (pentamethylene glycol), 1,2,6-hexanetriol, octylene glycol (ethohexadiol), butylene glycol (1,3-butylene glycol, 1,4-butylene glycol, 2,3 -Butanediol, etc.), hexylene glycol, 1,3-propanediol (trimethylene glycol), 1,6-hexanediol (hexamethylene glycol) and the like. Of these polyhydric alcohols, glycerin, diglycerin, ethylene glycol, propylene glycol and polyethylene glycol are preferred, glycerin and diglycerin are more preferred, and glycerin is particularly preferred. Examples of the polyhydric alcohol derivative include ester compounds and ether compounds of the polyhydric alcohol.

  The plasticizer softens the adhesive gel, facilitates the elongation of the adhesive gel at the time of peeling, and delays the transmission of a rapid pulling force to the skin, thereby relieving skin irritation. When an oily (liquid) polyhydric alcohol having a hydrophilic hydroxyl group is used as the plasticizer, the polyhydric alcohol functions as a solvent even if moisture is lost from the adhesive gel, and the gel is difficult to cure.

5. Mixing ratio In the adhesive gel according to the present invention, the weight ratio of the hydrophilic polymer to the acrylamide polymer is 1: 1 to 1:10, and the polyhydric alcohol, the hydrophilic polymer and the acrylamide polymer are high. It is preferable that the weight ratio of the molecule is 2: 1 to 6: 1. More preferably, the weight ratio of the hydrophilic polymer to the acrylamide polymer is 1: 2 to 1: 4, and the weight ratio of the polyhydric alcohol to the hydrophilic polymer and the acrylamide polymer is 3: 1 to 1. 5: 1.

  The preferred composition of the adhesive gel according to the present invention is that the hydrophilic polymer is either ether-modified PVA, a combination of PVA and PVP, a combination of ether-modified PVA and PVP, and an acrylamide type. The polymer is PNVA-PAS. In this case, the weight ratio of the hydrophilic polymer to the acrylamide polymer is 1: 2 to 1: 4, and the weight ratio of the polyhydric alcohol, the hydrophilic polymer and the acrylamide polymer is 3: It is preferably 1 to 5: 1. The ether-modified PVA preferably has a C6-22 linear or branched alkyl group as a substituent.

Further, the adhesive gel according to the present invention has a hydrophilic polymer content of 2 to 10% by weight, PNVA-PAS of 10 to 25% by weight, and a polyhydric alcohol of 60 to 95 in the weight ratio range. It is preferable to be set to% by weight.
Specifically, for example, when the weight ratio of the hydrophilic polymer to the acrylamide polymer is 1: 2, the hydrophilic polymer is 5.88 to 8.33 wt%, and the PNVA-PAS is 11.76 to Examples are 16.66% by weight and 75-83.3% by weight of polyhydric alcohol. For example, when the weight ratio of the hydrophilic polymer to the acrylamide polymer is 1: 4, the hydrophilic polymer is 3.33 to 5.0% by weight, and the PNVA-PAS is 13.32 to 20% by weight. The polyhydric alcohol is exemplified by 75 to 83.3% by weight. Note that these specific numerical ranges are merely examples.

  When the weight ratio of the acrylamide polymer to the hydrophilic polymer is less than the above numerical range, the wettability during drying is insufficient and sufficient tackiness cannot be obtained. If the wettability during drying is poor, it may cause skin irritation at the time of peeling and may damage the skin. On the other hand, when the weight ratio exceeds the above numerical range, the gel strength at the time of moisture content is insufficient and easily collapses.

  In addition, when the weight ratio of the polyhydric alcohol to the hydrophilic polymer and the acrylamide polymer is less than the above numerical range, the wettability during drying is insufficient and sufficient tackiness cannot be obtained. On the other hand, when the weight ratio exceeds the above numerical range, the polyhydric alcohol bleeds out from the gel, prevents adhesion to the skin, and causes discomfort such as stickiness.

  When PVP is blended as a hydrophilic polymer in the adhesive gel according to the present invention, the weight ratio of PVP to acrylamide polymer is preferably 1: 100 to 1: 1.

  When the blending ratio of PVP exceeds the above numerical range, the aqueous solution viscosity becomes too high in the production process, and uniform mixing cannot be performed or coating cannot be performed. Moreover, the ratio of the molecule | numerator bridge | crosslinked in hydrogel may fall and preparation of hydrogel may become difficult.

  In the pressure-sensitive adhesive gel according to the present invention, the weight ratio of water when containing water is preferably 50 to 70% of the total weight.

  When the mixing ratio of water is less than the above numerical range, the aqueous solution viscosity becomes too high in the production process, and uniform mixing cannot be performed or coating cannot be performed. In addition, the gel strength at the time of hydration may be insufficient, or the creation of a hydrogel may be difficult due to an increase in the solvent component.

6). Method for Producing Adhesive Gel The adhesive gel according to the present invention can be obtained by adding an aluminum compound to a mixed liquid containing a hydrophilic polymer, an acrylamide polymer, a polyhydric alcohol and water.

  Specifically, first, the hydrophilic polymer is dissolved with water and a polyhydric alcohol in accordance with the above-described blending ratio (dissolution step). Next, an acrylamide polymer is added to the solution to prepare a mixed solution (mixing step). In the dissolution step and the mixing step, additives such as a pH adjuster and a preservative may be added as necessary. Moreover, in a melt | dissolution process and a mixing process, you may heat and cool as needed.

  Subsequently, an aluminum compound is added to the mixed solution to perform a crosslinking reaction (crosslinking step). As a result, the acrylamide polymers are cross-linked by a cross-linking reaction to form an acrylamide polymer block. Also in the cross-linking step, heating and cooling can be performed as necessary, thereby adjusting the cross-linking reaction rate.

  In the following examples, a case where ether-modified PVA is used as the hydrophilic polymer, PNVA-PAS as the acrylamide polymer, and glycerin as the polyhydric alcohol will be described. Note that the combination of the hydrophilic polymer, the acrylamide polymer, and the polyhydric alcohol is merely an example, and is not limited thereto.

<Example 1>
A hydrogel was prepared by the following procedure.
(1) Dissolution Step After adding 20 parts by mass of water to a separable flask, an additive (0.06 parts by mass of tartaric acid, 0.03 parts by mass of methyl paraben) was added to prepare a mixed liquid 1.
6 parts by mass of glycerin, ether-modified polyvinyl alcohol (Nippon Vinegar Poval Co., Ltd., ZDF-17L (C16 linear alkyl group (substituent) was ether-bonded, and ketone group (functional group) was introduced. Modified PVA) 1 part by mass and poly N vinylacetamide-sodium acrylate copolymer (Showa Denko KK, adHERO GE167) 1 part by mass were mixed to prepare a mixed solution 2.
The mixed solution 2 was added to the mixed solution 1 with stirring, heated to 90 ° C., and then dissolved with stirring for 2 hours to prepare an aqueous solution 1.
(2) Crosslinking step A mixture of 2 parts by mass of glycerin and 0.06 parts by mass of dry aluminum hydroxide gel (Kyowa Chemical Industry Co., Ltd.) is added to the aqueous solution 1 at room temperature and stirred for 30 minutes while heating to 50 ° C. Aqueous solution 2 was prepared.
(3) Coating process After coating the aqueous solution 2 on a separator film to a thickness of 1 mm to form a coating-form hydrosol, it is sandwiched with another separator film and cured at 50 ° C. for 24 hours to form a gel. Got. The hydrogel was laminated with a knitted fabric. The total amount of water added in each step was 20 parts by mass, and glycerin was 8 parts by mass. The blending ratio is shown in “Table 1”.

<Example 2>
A hydrogel was produced in the same manner as in Example 1 except that the blending ratio was changed as shown in “Table 1”.

<Examples 3 to 5>
A hydrogel was prepared by the following procedure.
(1) Dissolution process After adding 30 parts by mass of water into a separable flask, additives (tartaric acid 0.12 parts by mass (Examples 3 and 4), 0.13 parts by mass (Example 5), methylparaben 0.06 parts by mass Part) was added to prepare a mixed solution 1.
14 parts by mass of glycerin, 3 parts by mass of ether-modified polyvinyl alcohol (Nippon Vitamin Poval Co., Ltd., 1 part by mass of ZDF-17L, poly N vinylacetamide-sodium acrylate copolymer (Showa Denko Co., Ltd., adHERO GE167)) Thus, a liquid mixture 2 was prepared.
The mixed solution 2 was added to the mixed solution 1 with stirring, heated to 90 ° C., and then dissolved with stirring for 2 hours to prepare an aqueous solution 1.
Moreover, after putting 10 mass parts of water into another separable flask, polyvinyl pyrrolidone (BASF, rubiscol K-90) 1.2 mass parts (Example 3), 2.4 mass parts (Example 4), 3 After adding 6 parts by mass (Example 5) and heating to 50 ° C., the mixture was dissolved with stirring for 1 hour to prepare an aqueous solution 2.
(2) Mixing Step Aqueous solution 1 and aqueous solution 2 were cooled to room temperature, mixed, heated to 90 ° C., and stirred for 2 hours to prepare aqueous solution 3.
(3) Crosslinking step 2 parts by mass of glycerin in the aqueous solution 3, 0.1 parts by mass (Example 3), 0.12 parts by mass (Example 4), 0.13 parts by dry aluminum hydroxide gel (Kyowa Chemical Industry Co., Ltd.) A mixed solution of parts by mass (Example 5) was added at room temperature and stirred for 30 minutes while heating to 50 ° C. to prepare an aqueous solution 4.
(4) Coating process After the aqueous solution 4 is coated on a separator film to a thickness of 1 mm to form a coating-form hydrosol, it is sandwiched between different separator films and cured at 50 ° C. for 24 hours to form a gel. Got. The hydrogel was laminated with a knitted fabric. The total amount of water added in each step was 40 parts by mass, and glycerin was 16 parts by mass. The blending ratio is shown in “Table 1”.

<Example 6>
A hydrogel was produced in the same manner as in Example 1 except that the blending ratio was changed as shown in “Table 1”.

<Examples 7 to 9>
A hydrogel was produced in the same manner as in Examples 3 to 5 except that the blending ratio was changed as shown in “Table 1”.

<Example 10>
A hydrogel was produced in the same manner as in Example 1 except that the blending ratio was changed as shown in “Table 1”.

<Example 11>
A hydrogel was produced in the same manner as in Examples 3 to 5 except that the blending ratio was changed as shown in “Table 1”.

<Examples 12 and 13>
A hydrogel was produced in the same manner as in Example 1 except that the blending ratio was changed as shown in “Table 2”.

<Examples 14 to 16>
A hydrogel was produced in the same manner as in Examples 3 to 5 except that the blending ratio was changed as shown in “Table 2”.

<Example 17>
A hydrogel was produced in the same manner as in Example 1 except that the blending ratio was changed as shown in “Table 2”.

<Example 18>
A hydrogel was produced in the same manner as in Examples 3 to 5 except that the blending ratio was changed as shown in “Table 2”.

<Examples 19 to 21>
A hydrogel was produced in the same manner as in Example 1 except that the blending ratio was changed as shown in “Table 2”.

<Example 22>
A hydrogel was prepared in the same manner as in Examples 3 to 5 according to “Table 2”, except that polyvinyl alcohol was used instead of modified polyvinyl alcohol.

<Example 23>
A hydrogel was produced in the same manner as in Example 1 except that the blending ratio was changed as shown in “Table 3”.

<Examples 24-26>
A hydrogel was produced in the same manner as in Examples 3 to 5 except that the blending ratio was changed as shown in “Table 3”.

<Examples 27 to 29>
A hydrogel was produced in the same manner as in Example 1 except that the blending ratio was changed as shown in “Table 3”.

<Examples 30 to 35>
A hydrogel was prepared in the same manner as in Example 1 except that polyvinyl alcohol or polyvinyl pyrrolidone was used instead of the modified polyvinyl alcohol, according to the blending ratio of “Table 3”.

<Comparative Examples 1-5>
A hydrogel was produced in the same manner as in Example 1 except that the blending ratio was changed as shown in “Table 4”. APA P 250 was used as a crosslinking agent for the modified polyvinyl alcohol. Moreover, potassium dihydrogen phosphate was used as a pH adjuster.

<Comparative Example 6>
A hydrogel was prepared in the same manner as in Example 1 except that the hydrophilic polymer was not used, in accordance with the blending ratio of “Table 4”.

The following evaluation was performed about the hydrogel produced by the Example and the comparative example.
(1) Strength at the time of water content Hydrogel that has been cured for 3 days or more at room temperature while being sandwiched between separator films after production is rubbed with a thumb and index finger and rubbed. It was evaluated according to the criteria. The results are shown in the lower part of “Table 1” to “Table 4”.
5: Excellent (cohesive strength is very high and does not collapse at all)
4: Good (cohesive strength is high and does not collapse)
3: Acceptable 2: Poor (cohesive force is low and part of the gel has collapsed)
1: Impossible (the cohesive force is very low and the gel completely disintegrates)

  The strength (cohesive force) when containing water can be achieved by using a hydrophilic polymer exhibiting crystallinity such as polyvinyl alcohol. Polyvinyl alcohol can maintain cohesion without relying on crosslinking. That is, since polyvinyl alcohol has many hydroxyl groups in the structure, it is dispersed in the polymer matrix and forms strong hydrogen bonds. Thereby, it was thought that polyvinyl alcohol contributed to improving the whole cohesion force at the time of moisture containing.

(2) Wetting adhesiveness at the time of drying The hydrogel peeled off from the separator film after preparation was allowed to stand at room temperature for 24 hours to evaporate water. The index finger was pressed against the dried hydrogel, and the flexibility and tackiness of the gel were evaluated according to the following criteria. The results are shown in the lower part of “Table 1” to “Table 4”.
5: Excellent (exhibits very good wetness and stickiness)
4: Good (wet well and exhibit adhesiveness)
3: Possible 2: Poor (due to curing, insufficient wettability and insufficient tackiness)
1: Impossible (curing progresses, no stickiness)

  The wettability (softness) and tackiness during drying can be achieved by the characteristics of the acrylamide polymer. Since the acrylamide polymer has an amide group, it forms a hydrogen bond and dissolves in water like polyvinyl alcohol. In addition, the acrylamide polymer is very compatible with the polyhydric alcohol and does not form a hydrogen bond as strong as polyvinyl alcohol, and thus can be plasticized with a small amount of glycerin. By blending PNVA-PAS and glycerin, it was considered that a hydrogel showing adhesiveness was obtained while maintaining wettability (softness) even after drying.

(3) Cooling feeling when containing water Hydrogel cured for 3 days or more at room temperature while being sandwiched between separator films after production was applied to the skin, and the cooling feeling at the time of application was evaluated according to the following criteria.

  As a result, in the hydrogel according to Examples, excellent cooling feeling was confirmed in all Examples. On the other hand, the same cooling feeling was felt also in the hydrogel according to the comparative example. From this result, it was found that a feeling of cooling is felt when the ratio of water in the total weight is at least 55% by weight or more.

  In addition, after leaving the hydrogel of Example 11 on a 60 degreeC hotplate to evaporate a water | moisture content and adjusting so that a moisture content might be 25, 30, 35, 40 weight% of the whole weight, the same test Went. As a result, it was confirmed that when the moisture content was 30% by weight or more, a feeling of cooling was felt at the time of application.

  From the above results, the ratio of hydrophilic polymer (PVA or modified PVA) to acrylamide polymer is 1: 2 to 1: 4. Polyhydric alcohol, hydrophilic polymer (PVA or modified PVA) and acrylamide It can be seen that when the weight ratio to the polymer is 3: 1 to 5: 1, the strength when water is contained and the adhesiveness when dried are most excellent. Even if the ratio of the hydrophilic polymer to the acrylamide polymer is 1: 1, the weight of the polyhydric alcohol may be 4 times or 5 times the weight of the hydrophilic polymer and the acrylamide polymer. For example, it is known that it is suitable for strength when wet and adhesiveness when dried (not shown in the table).

When PVA was used alone as the hydrophilic polymer, the strength when containing water was good, but the wettability during drying was poor (see Examples 30 to 32). This is considered to be caused by poor compatibility of PVA with glycerin (PVA does not dissolve in glycerin). That is, it is considered that the number of hydrogen bonds due to hydroxyl groups in PVA is increased.
In addition, although the case where the weight ratio of PNVA-PAS with respect to PVA is 1: 3 or more is not examined, it can estimate | forecast that the intensity | strength at the time of a water | moisture content will not be obtained because the addition rate of PVA falls.

  Moreover, when PVP was used alone as the hydrophilic polymer, the wettability during drying was good, but the strength when containing water was poor (see Examples 33 to 35). This is presumably because PVP forms a hydrogen bond derived from an amide group and thus has high compatibility with glycerin and can maintain wettability after drying. However, it is considered that the effect of improving the strength at the time of hydration was not obtained because the bond strength was small compared with that derived from a hydroxyl group.

  When ether-modified PVA was used as the hydrophilic polymer, both strength when wet and wettability when dried were good (see, for example, Examples 2, 6, and 10). This is thought to be because long-chain alkyl groups ether-terminated at the ends enter between the hydroxyl groups in the matrix during drying to inhibit the formation of hydrogen bonds.

  Even when PVA and PVP were used in combination as hydrophilic polymers, both the strength when wet and the wettability during drying were good (see Example 22). This was considered to be mainly due to a decrease in the hydroxyl group concentration in the matrix. That is, it was considered that the ratio of PVA in the matrix decreased and the ratio of the matrix (PVP, PNVA-PAS) that could be dissolved in glycerin increased.

  Further, when ether-modified PVA and PVP were used in combination as hydrophilic polymers, both the strength when wet and the wettability when dried were good (see, for example, Examples 3 to 5). As described above, this was thought to be because long-chain alkyl groups ether-terminated at the ends entered between the hydroxyl groups in the matrix, thereby inhibiting the formation of hydrogen bonds. In addition, a decrease in the hydroxyl group concentration in the matrix was considered as a factor.

The adhesive gel which concerns on this invention is used suitably for the following uses.
(1) It can be suitably used as a covering material for the purpose of antipruritics, anti-inflammation, pruritus prevention, etc. against itching of skin due to atopy and other skin diseases.
(2) It can be suitably used as a wound dressing for the purpose of maintaining a moist environment and reducing pain against dry wounds, burns, and other wounds.
(3) For diseases such as pressure ulcers, foot diseases (diabetic foot ulcers, venous leg ulcers, peripheral arterial diseases, etc.), scars, keloids, hand-foot syndrome, etc. that are caused or exacerbated by external pressure and tension On the other hand, it can be suitably used as a patch for the purpose of protecting the target site and relaxing pressure and tension.
(4) A patch for fixing a catheter, gauze, or other medical material to the human body. In particular, it can be suitably used for infants, elderly people, and other patients with fragile skin.
(5) It can be suitably used as a patch (pack material) for the purpose of skin care or beauty due to skin retention of moisture retention or physiologically active substances.
(6) It can be suitably used as a poultice material (pap material) for the purpose of alleviating and preventing pain and fatigue such as stiff shoulders, back pain, bruises, muscle pain, muscle fatigue, sprains, joint pain, and fracture pain.

Claims (8)

It contains polyhydric alcohol and water in a matrix of hydrophilic polymer and acrylamide polymer,
The weight ratio of hydrophilic polymer to acrylamide polymer is 1: 1 to 1:10, and
An adhesive gel in which the weight ratio of the polyhydric alcohol to the hydrophilic polymer and the acrylamide polymer is 2: 1 to 6: 1.   The adhesive gel according to claim 1, comprising polyvinyl alcohol as the hydrophilic polymer.   The adhesive gel according to claim 2, wherein the polyvinyl alcohol is ether-modified polyvinyl alcohol.   The adhesive gel according to claim 3, wherein the ether-modified polyvinyl alcohol has a linear or branched alkyl group having 6 to 22 carbon atoms as a substituent.   The adhesive gel according to claim 1, wherein the acrylamide polymer includes an N-vinylacetamide-sodium acrylate copolymer. As the hydrophilic polymer, further contains polyvinylpyrrolidone,
The pressure-sensitive adhesive according to any one of claims 1 to 5, wherein a weight ratio of polyvinylpyrrolidone and N-vinylacetamide-sodium acrylate copolymer is 1: 100 to 1: 1.   The pressure-sensitive adhesive gel according to any one of claims 1 to 6, comprising 30 to 75% by weight of water when containing water. It contains polyhydric alcohol and water in a matrix of hydrophilic polymer and acrylamide polymer,
The weight ratio of the hydrophilic polymer to the acrylamide polymer is 1: 2 to 1: 4, and the weight ratio of the polyhydric alcohol to the hydrophilic polymer and the acrylamide polymer is 3: 1 to 1. 5: 1
The acrylamide polymer is N-vinylacetamide-sodium acrylate copolymer,
The adhesive gel whose hydrophilic polymer is either of the following (1)-(3).
(1) Ether-modified polyvinyl alcohol.
(2) A combination of polyvinyl alcohol and polyvinyl pyrrolidone.
(3) A combination of ether-modified polyvinyl alcohol and polyvinylpyrrolidone.