HK1216612B - Cataplasm and method for producing same - Google Patents

Description

Mud patch and its manufacturing method

Technical Field

The present invention relates to a paste patch and a method for producing the same.

Background Art

A paste patch is a type of patch made by applying a paste containing a pharmaceutical agent onto a support such as cloth. Generally, they are characterized by their high water content, thick paste, and minimal skin irritation. However, the adhesion of a paste patch often decreases over time after application. For example, Patent Documents 1 and 2 below investigate methods to prevent this decrease in adhesion.

Prior art literature

Patent Literature

Patent Document 1: Japanese Patent Application Laid-Open No. 9-208462

Patent Document 2: International Publication No. 2006/090782

Summary of the Invention

Problems to be solved by the invention

However, the paste patches described in Patent Documents 1 and 2 sometimes exhibit insufficient adhesion when the paste thickness is reduced or after prolonged application. Furthermore, the aqueous external patch described in Patent Document 2, which contains a partially neutralized polyacrylic acid and sodium polyacrylate, still faces challenges regarding pH increase, formability, shape retention, and skin irritation. Therefore, the present invention aims to provide a paste patch that maintains sufficient adhesion even when its water content decreases over time.

Means of solving problems

The present invention provides a paste patch comprising a paste layer on a support, wherein the paste layer is obtained by mixing at least a neutralized polyacrylic acid, a poly(methyl acrylate/2-ethylhexyl acrylate) emulsion (hereinafter also referred to as "methyl acrylate-2-ethylhexyl acrylate copolymer resin emulsion") in an amount of 2.5 times or more, preferably 3 times or more, by mass of the neutralized polyacrylic acid, and water.

The paste layer of the paste patch of the present invention is composed of at least water, a neutralized polyacrylic acid, and a poly(methyl acrylate/2-ethylhexyl acrylate) emulsion, wherein the mass of the poly(methyl acrylate/2-ethylhexyl acrylate) emulsion is at least 2.5 times, preferably at least 3 times, the mass of the neutralized polyacrylic acid. With such a composition, the paste patch of the present invention can maintain sufficient adhesion even after a long period of time after application.

The poly(methyl acrylate/2-ethylhexyl acrylate) emulsion is preferably an emulsion containing poly(oxyethylene) nonylphenyl ether. Particularly preferred is an emulsion using poly(oxyethylene) nonylphenyl ether as a surfactant or protective colloid. Using such an emulsion can improve adhesion retention.

The polyacrylate is preferably a partially neutralized polyacrylic acid. By using a partially neutralized polyacrylic acid rather than a completely neutralized polyacrylic acid as the polyacrylate, both the initial adhesion and the adhesion after a long period of time after application can be improved.

The water content in the paste layer is preferably greater than the mass of the poly(methyl acrylate/2-ethylhexyl acrylate) emulsion.

The water content in the paste layer is preferably 4 times or more of the mass of the neutralized polyacrylic acid.

The paste layer is preferably obtained by mixing a neutralized polyacrylic acid, a poly(methyl acrylate/2-ethylhexyl acrylate) emulsion, and water in a mass ratio of neutralized polyacrylic acid: poly(methyl acrylate/2-ethylhexyl acrylate) emulsion: water = 1:2.5-7:5-16. More preferably, the neutralized polyacrylic acid, a poly(methyl acrylate/2-ethylhexyl acrylate) emulsion, and water in a mass ratio of neutralized polyacrylic acid: poly(methyl acrylate/2-ethylhexyl acrylate) emulsion: water = 1:2.5-7:7-16. By mixing in such a ratio, the adhesion maintenance performance can be improved.

The water content in the paste layer is preferably 20 to 60% by mass based on the total mass of the paste layer. By making the water content fall within the above range, it is easier to obtain synergistic adhesion through the adhesion of the neutralized polyacrylic acid and the adhesion of poly(methyl acrylate/2-ethylhexyl acrylate).

The content of the neutralized polyacrylic acid in the paste layer is preferably 1 to 6% by mass, based on the total mass of the paste layer. By adjusting the content of the neutralized polyacrylic acid within this range, sufficient adhesion can be achieved even when the water content is high, and the hardness of the paste patch can be reduced. Furthermore, by reducing the hardness of the paste patch, adhesion to the skin is improved, further enhancing adhesion.

The paste layer preferably further contains polyacrylic acid. By containing polyacrylic acid, the adhesiveness can be maintained at a high level and the shape retention of the paste patch can be improved.

The mass of the paste layer can be, for example, 214 to 1000 g/ ^m² , 400 to 1000 g/ ^m² , or 400 to 650 g/ ^m² . Conventional paste patches tend to have lower water content and reduced adhesion when the paste layer weight is low. However, according to the present invention, even with a relatively low paste layer weight as described above, sufficient adhesion can be maintained over a long period of time.

The paste patch of the present invention has adhesion based on the poly(methyl acrylate/2-ethylhexyl acrylate) in the poly(methyl acrylate/2-ethylhexyl acrylate) emulsion and the neutralized polyacrylic acid. It is believed that, with respect to the adhesion when the water content of the paste layer is 30% by mass or more, the adhesion of the neutralized polyacrylic acid is greater than the adhesion of poly(methyl acrylate/2-ethylhexyl acrylate), and with respect to the adhesion when the water content of the paste layer is less than 25% by mass, the adhesion of poly(methyl acrylate/2-ethylhexyl acrylate) is greater than the adhesion of the neutralized polyacrylic acid. Therefore, even if the water content of the paste patch decreases over time, sufficient adhesion can be exerted.

The present invention provides a method for producing a paste patch comprising a paste layer on a support that maintains adhesion even when the water content is reduced. Specifically, the paste layer is obtained by adding a poly(methyl acrylate/2-ethylhexyl acrylate) emulsion in a neutralized product of water and polyacrylic acid in an amount 2.5 times or more by mass of the neutralized product to produce a paste patch that maintains adhesion even when the water content is reduced.

Effects of the Invention

The paste patch of the present invention can maintain sufficient adhesion even after a long period of time has passed since application and the water content in the paste layer has decreased.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graph showing the change over time in the adhesive force of the gel patch produced in Comparative Example 1. FIG.

FIG. 2 is a graph showing the temporal change in the adhesive force of the gel patch produced in Example 1. FIG.

FIG. 3 is a graph showing the change over time in the adhesive force of the gel patch produced in Example 2. FIG.

FIG. 4 is a graph showing the relationship between the adhesive force and the water content of the gel patches prepared in Examples 1 and 2 and Comparative Example 1. FIG.

FIG. 5 is a graph showing the peel strength of the gel patches prepared in Examples 3 and 4 and Comparative Example 5 after 8 hours.

FIG. 6 is a graph showing the temporal change in the adhesive force of the gel patches produced in Example 6 and Comparative Example 6. FIG.

DETAILED DESCRIPTION

Hereinafter, preferred embodiments of the present invention will be described in detail.

The paste patch of the present embodiment has a paste layer on a support. As a support, any material that can support an aqueous paste obtained by mixing at least a neutralized polyacrylic acid, a poly(methyl acrylate/2-ethylhexyl acrylate) emulsion, and water can be used. Examples of such a support include woven fabrics, non-woven fabrics, resin films, foamed sheets, and paper. Examples of woven fabrics include knitted fabrics. When using woven fabrics, non-woven fabrics, or resin films as a support, examples of raw materials include polyolefins such as polyethylene, polypropylene, and polybutene, polyesters such as polyethylene terephthalate, rayon, polyurethane, and cotton. These materials can be used alone or in combination of two or more. Polyester is more preferred as a support.

The support is preferably a nonwoven fabric or a woven fabric, particularly preferably one having a predetermined tensile elastic recovery. The tensile elastic recovery herein refers to the value measured in accordance with "JIS L1096: Testing Methods for Materials of Woven and Knitted Fabrics." Using a nonwoven fabric or a woven fabric with a predetermined tensile elastic recovery is preferred because it allows the support to expand and contract in response to the movement of the attachment site when attached to a movable part such as a joint.

When the support is a nonwoven fabric, the load at 50% stretch is preferably, for example, 1 to 5 N/2.5 cm in the longitudinal direction (long axis direction) and 0.1 to 3 N/2.5 cm in the transverse direction (minor axis direction). Furthermore, the elastic recovery rate at 50% stretch is, for example, 60 to 99%, preferably 65 to 95%, and more preferably 70 to 90%. Suitable unit weights of the support are, for example, 80 to 120 g/ ^m² , preferably 90 to 110 g/ ^m² . Suitable thicknesses of the support are, for example, 0.5 to 2 mm. Furthermore, the stiffness of the support (stiffness is measured according to the JIS L1096 45° cantilever method) is, for example, 20 to 40 mm in the longitudinal direction (long axis direction) and 10 to 35 mm in the transverse direction (minor axis direction), preferably 25 to 35 mm in the longitudinal direction (long axis direction) and 15 to 30 mm in the transverse direction (minor axis direction).

When a woven fabric, particularly a knitted fabric, is used as the support for the present invention, it also includes a knitted fabric obtained by combining loops by circular knitting, longitudinal knitting, horizontal knitting, etc. into a cloth-like shape. Preferred examples of knitted fabrics include knitted fabrics made from a combination of one or more materials such as polyester, nylon, polypropylene, and rayon. Among them, knitted fabrics containing polyethylene terephthalate, a polyester that has little interaction with chemical reagents, are more preferred.

In particular, when the support is a woven fabric, the load at 50% stretch is preferably, for example, 1 to 5 N/2.5 cm in the longitudinal direction (long axis direction) and 0.1 to 3 N/2.5 cm in the transverse direction (minor axis direction). Furthermore, the 50% stretch elastic recovery is, for example, 60 to 99%, preferably 65 to 95%, and more preferably 70 to 90%. Furthermore, the stiffness of the support is, for example, 10 to 30 mm in the longitudinal direction (long axis direction) and 10 to 30 mm in the transverse direction (minor axis direction), preferably 15 to 25 mm in the longitudinal direction (long axis direction) and 15 to 25 mm in the transverse direction (minor axis direction).

When a water-containing paste is spread on a woven fabric, water may seep through the mesh of the fabric. However, by setting the basis weight of the polyethylene terephthalate fabric to 80-150 g/ ^m² , the water contained in the paste tends to spread without seeping through the mesh of the fabric, and the anchoring property between the fabric and the paste can be maintained.

In addition, polyethylene terephthalate fabrics preferably have a longitudinal (long-axis) elastic modulus of 2 to 12 N/5 cm and a transverse (short-axis) elastic modulus of 2 to 8 N/5 cm (elastic modulus measurement method in accordance with JIS L 1018). If the elastic modulus is less than 2 N/5 cm, the paste may spread on the fabric during application, causing the adhesive to penetrate the mesh, thereby reducing its function as a paste patch. Furthermore, if the elastic modulus is greater than 12 N/5 cm (longitudinal) or 8 N/5 cm (transverse), the fabric may have poor elasticity and may not easily adapt to the flexion and extension of the skin when applied to curved areas.

By spreading the paste of the present invention on such a woven fabric, particularly a knitted fabric, it can be applied for a longer period of time.

The paste layer constituting the gel patch is composed of an aqueous paste obtained by mixing at least a neutralized polyacrylic acid, a poly(methyl acrylate/2-ethylhexyl acrylate) emulsion, and water.

The neutralized polyacrylic acid may be a completely neutralized polyacrylic acid, a partially neutralized polyacrylic acid, or a mixture thereof. Examples of the neutralized polyacrylic acid include polyacrylates, such as sodium salts, potassium salts, calcium salts, and ammonium salts.

As the neutralized polyacrylic acid, partially neutralized polyacrylic acid is preferred due to its high initial adhesion and long-term adhesion. A partially neutralized polyacrylic acid is one in which structural units derived from acrylic acid and structural units derived from acrylate salts are present in any ratio within a single polymer chain. As the partially neutralized polyacrylic acid, one in which 50 mol% of the carboxyl groups within a single polymer chain are neutralized is preferred.

The content of the neutralized polyacrylic acid in the paste layer is preferably 1 to 6% by mass, more preferably 2 to 6% by mass, based on the total mass of the paste layer. By setting the content of the neutralized polyacrylic acid to 1% by mass or more, sufficient adhesion of the neutralized polyacrylic acid can be achieved, while by setting the content of the neutralized polyacrylic acid to 6% by mass or less, the formability and shape retention of the paste layer can be improved.

The poly(methyl acrylate/2-ethylhexyl acrylate) emulsion (methyl acrylate-2-ethylhexyl acrylate copolymer resin emulsion) constituting the paste layer is preferably an aqueous emulsion using water as a medium. In addition, as the poly(methyl acrylate/2-ethylhexyl acrylate) emulsion, an emulsion using polyoxyethylene nonylphenyl ether as a surfactant or protective colloid is preferred. In addition, the evaporation residue (non-volatile component) when heated at a temperature above the boiling point of the medium (for example, heating at 105°C for 3 hours) is preferably 57 to 61%. As such an emulsion, NIKASOL TS-620 (trade name, manufactured by Nippon Carbide Industries, Ltd.) can be cited. According to the Japanese Pharmaceutical Additives Standard (2013), after NIKASOL TS-620 is evaporated to dryness on a water bath, it is dried at 105°C for 3 hours. At this time, the amount of evaporation residue is 57 to 61%.

The content of the poly(methyl acrylate/2-ethylhexyl acrylate) emulsion in the paste layer is 5 to 25% by mass, preferably 10 to 20% by mass, more preferably 10 to 18% by mass, and even more preferably 6 to 22% by mass, based on the total mass of the paste layer.

The water content in the plaster layer is preferably 20 to 60% by mass, more preferably 25 to 50% by mass, based on the total mass of the plaster layer. By setting the water content to 20 to 60% by mass, even if the water evaporates during application, the adhesive force generated by the polyacrylate and poly(methyl acrylate/2-ethylhexyl acrylate) emulsion can be fully exerted, and the adhesion to the skin can be further improved.

The mass of the poly(methyl acrylate/2-ethylhexyl acrylate) emulsion in the paste layer is preferably 2.5 times or more, more preferably 2.7 times or more, and even more preferably 3 times or more of the mass of the neutralized polyacrylic acid. Furthermore, the mass of the poly(methyl acrylate/2-ethylhexyl acrylate) emulsion in the paste layer is preferably 10 times or less, more preferably 7 times or less, and even more preferably 5 times or less of the mass of the neutralized polyacrylic acid.

The mass of water in the paste layer is preferably at least 1 times the mass of the poly(methyl acrylate/2-ethylhexyl acrylate) emulsion, more preferably at least 1.5 times, and even more preferably at least 2 times. Furthermore, the mass of water in the paste layer is preferably at most 50 times the mass of the poly(methyl acrylate/2-ethylhexyl acrylate) emulsion, more preferably at most 20 times, and even more preferably at most 7 times.

The mass of water in the paste layer is preferably 4 times or more, more preferably 5 times or more, and even more preferably 6 times or more of the mass of the neutralized polyacrylic acid. Furthermore, the mass of water in the paste layer is preferably 20 times or less, more preferably 15 times or less of the mass of the neutralized polyacrylic acid.

The paste layer is preferably prepared by mixing a neutralized polyacrylic acid, a poly(methyl acrylate/2-ethylhexyl acrylate) emulsion, and water in a mass ratio of neutralized polyacrylic acid:poly(methyl acrylate/2-ethylhexyl acrylate) emulsion:water = 1:2.5-7:7-16. This ratio is more preferably 1:3-5:7-12. By adopting this ratio, the effect of the present invention, namely, maintaining adhesion, can be further enhanced.

Even when the water content of the gel patch having the above-mentioned structure becomes less than 25% by mass due to evaporation of water over time, the gel patch as a whole can maintain sufficient adhesion due to the adhesion of poly(methyl acrylate/2-ethylhexyl acrylate).

The paste layer, except above-mentioned essential components, also can contain medicament in addition.As such medicament, as long as there is percutaneous absorbability, for example, can enumerate nonsteroidal anti-inflammatory drugs such as felbinac, flurbiprofen, diclofenac, diclofenac sodium, methyl salicylate, glycol salicylate, indomethacin, ketoprofen or their esters, antihistamines such as diphenhydramine, analgesics such as aspirin, acetaminophen, ibuprofen, loxoprofen sodium, local anesthetics such as lidocaine, muscle relaxants such as succinylcholine chloride, antifungals such as clotrimazole, antihypertensives such as clonidine, nitroglycerin, vasodilators such as isosorbide dinitrate, vitamin A, vitamin E (tocopherol), tocopheryl acetate, vitamin K, octhiamin, riboflavin butyrate, vitamins, prostaglandins, scopolamine, fentanyl, l-menthol, capsicum extract, vanillin nonamide etc.

In addition, the paste layer may include ingredients from fruits such as rosehip extract, orange extract, orange juice, raspberry extract, kiwi extract, cucumber extract, gardenia extract, grapefruit extract, hawthorn extract, pepper extract, hawthorn extract, juniper extract, jujube extract, longgong fruit extract, tomato extract, grape extract, loofah extract, lime juice, apple extract, apple juice, lemon extract, lemon juice, water-soluble placenta extract, allantoin, lecithin, amino acids, kojic acid, protein, sugars, hormones, placenta extract, aloe vera, licorice and other extracts from various Chinese medicinal materials.

Examples of other ingredients that can be mixed with the paste layer include angelica leaf extract, avocado extract, gypsophila extract, marshmallow extract, arnica flower extract, ginkgo extract, fennel extract, turmeric extract, oolong tea extract, scutellaria root extract, phellodendron amurense extract, barley extract, watercress extract, seaweed extract, hydrolyzed elastin, hydrolyzed wheat powder, hydrolyzed silk, chamomile extract, artemisia capillaris extract, licorice extract, karkade extract, guanosine, white bamboo extract, walnut extract, clematis extract, yeast extract, burdock extract, daisy extract, bilberry extract, bupleurum extract, umbilical cord extract, sage extract, soapwort extract, bamboo shoot extract, hawthorn extract, shiitake mushroom extract, rehmannia root extract, comfrey root extract, linden extract, spirea odorata extract, calamus root extract, birch extract, safflower extract, honeysuckle extract, and vinca root extract. Vine extract, hawthorn extract, elderberry extract, yarrow extract, peppermint extract, mallow extract, Japanese swertia extract, jujube extract, thyme extract, clove extract, imperata extract, tangerine peel extract, orange peel extract, Houttuynia cordata extract, natto extract, carrot extract, wild rose extract, hibiscus extract, ophiopogon extract, parsley extract, honey, medicinal wallwort extract, yarrow extract, bisabolol, coltsfoot flower extract, coltsfoot rhizome extract, Poria cocos extract, butcher's leaf extract, propolis, mint extract, bodhi tree extract, hops extract, pine extract, horse chestnut extract, water plantain extract, soapberry extract, peach leaf extract, cornflower extract, eucalyptus extract, grapefruit extract, wormwood extract, lavender extract, lettuce extract, astragalus extract, rose extract, rosemary extract, Roman chamomile extract, royal jelly extract, etc.

The plaster layer may also contain polyacrylic acid. The polyacrylic acid content is preferably 1 to 5% by mass, based on the mass of the plaster layer. A polyacrylic acid content of 1% by mass or greater improves the formability and shape retention of the plaster layer. A polyacrylic acid content of 5% by mass or less prevents the plaster layer from becoming too hard, improving its adhesion to the skin.

The pH of the paste layer is preferably 4 to 8, more preferably 4.5 to 6. By setting the pH to 4 or more, the irritation to the skin is reduced, and by setting the pH to 8 or less, the formability and shape retention of the paste patch can be improved. In particular, when the support is a woven fabric, especially a knitted fabric, although oozing sometimes occurs when the paste layer is formed, when the pH is 5 to 6.5, there is a tendency to suppress oozing. It should be noted that the pH can be measured, for example, by using a glass composite electrode and diluting the sample 20 times with purified water based on the pH determination method of the general test method of the Japanese Pharmacopoeia.

The paste layer may further contain other ingredients such as a water-soluble polymer, a solubilizing agent, a moisturizing agent, a cooling agent, a stabilizer, an inorganic powder, a colorant, a fragrance, and a pH adjuster.

The water-soluble polymer is not particularly limited as long as it can retain moisture in the paste, and any water-soluble polymer generally known to those skilled in the art can be used. Examples of the water-soluble polymer include gelatin, polyvinyl alcohol, polyvinyl pyrrolidone, sodium alginate, hydroxypropyl cellulose, sodium carboxymethyl cellulose, methyl cellulose, and carrageenan. One type can be used alone, or two or more types can be used in combination. Preferred water-soluble polymers are sodium carboxymethyl cellulose, gelatin, or polyvinyl alcohol.

The content of the water-soluble polymer is preferably 3 to 10% by mass based on the mass of the paste layer.

The cosolvent is not particularly limited as long as it can dissolve the drug, and examples thereof include crotamiton; N-methylpyrrolidone; polyalkylene glycols such as polyethylene glycol (PEG) and polybutylene glycol; fatty acid esters such as isopropyl myristate and diethyl adipate; oxyalkylene fatty acid esters such as polyethylene glycol monostearate; fatty acid esters such as polyoxyalkylene sorbitan fatty acid esters; polyoxyethylene hydrogenated castor oil; and surfactants such as polysorbate 80. These cosolvents may be used alone or in combination of two or more.

The content of the solubilizing agent is preferably 0.1 to 10% by mass based on the mass of the paste layer.

There are no particular limitations on the moisturizing agent, as long as it can inhibit the evaporation of water from the paste layer over time. Examples of moisturizing agents include polyols such as concentrated glycerin, sorbitol, ethylene glycol, propylene glycol, polyethylene glycol, liquid paraffin, 1,3-propylene glycol, and 1,4-butylene glycol. These moisturizing agents may be used alone or in combination of two or more. Concentrated glycerin is preferred as the moisturizing agent.

The content of the moisturizing agent is preferably 20 to 40% by mass based on the mass of the plaster layer.

Examples of the cooling agent include thymol, l-menthol, dl-menthol, l-isopulegol, and peppermint oil, and l-menthol is preferably used.

The content of the cooling agent is preferably 0.5 to 3% by mass based on the mass of the paste layer.

Examples of the stabilizer include oxybenzone, butylated hydroxytoluene (BHT), sodium edetate, and UV absorbers (eg, dibenzoylmethane).

The paste patch may also include a release liner. The release liner is laminated on the surface of the paste layer opposite the support. The presence of a release liner can suppress a decrease in the water content of the paste layer during storage, reducing the tendency of dirt and the like to adhere to the paste layer.

The material of the release liner is not particularly limited, and any liner generally known to those skilled in the art can be used. When a woven fabric, nonwoven fabric, knitted fabric, or resin film is used as the support, examples of such materials include polyethylene, polypropylene, polybutylene, polyethylene terephthalate, rayon, and polyurethane. These materials may be used alone or in combination of two or more. Polypropylene film is preferred as the material of the release liner.

The paste can be stored in a small pouch. By storing it in a small pouch, the water content of the paste layer can be suppressed from decreasing, and dirt and the like can be suppressed from adhering to the paste layer.

The mass of the paste layer of a paste patch can be 214 to 1000 g/ ^m² , 400 to 1000 g/ ^m² , or even 400 to 650 g/ ^m² . Preferably, a mass of 400 to 650 g/ ^m² can improve adhesion and provide a comfortable feel for a longer period of time. When the mass of the paste layer is within this range, the overall thickness of the paste patch can be reduced, making it easier to follow the skin. Furthermore, the difference in level with the surrounding area during application is reduced, making it less likely to peel.

In particular, as described above, when a paste patch is prepared by mixing a neutralized polyacrylic acid: poly(methyl acrylate/2-ethylhexyl acrylate) emulsion: water in a mass ratio of 1:2.5 to 7:7 to 16, and further when a paste patch is prepared by mixing a neutralized polyacrylic acid, a poly(methyl acrylate/2-ethylhexyl acrylate) emulsion, and water in a mass ratio of neutralized polyacrylic acid: poly(methyl acrylate/2-ethylhexyl acrylate) emulsion: water in a mass ratio of 1:2.5 to 7:5 to 16, the mass of the paste is preferably 400 g/ ^m2 or more because the water in the paste is easily volatilized and the adhesion tends to decrease when the mass of the paste is less than 400 g/ ^m2 .

The paste patch is obtained by mixing a neutralized polyacrylic acid, a poly(methyl acrylate/2-ethylhexyl acrylate) emulsion in an amount of 2.5 times or more by mass of the neutralized polyacrylic acid, and water, and adding other ingredients as described above as needed to obtain an aqueous paste. The aqueous paste is evenly spread on a release liner, a support is laminated thereon, and the release liner is peeled off to form a paste layer on the support.

The above-mentioned paste patch can maintain sufficient adhesion even after a long period of time since application. The adhesion can be measured, for example, by the adhesion score or peel strength described below. Here, the adhesion score is 75 points or more.

Example

The gel patches of the present invention are described in detail below using Examples and Test Examples, but the present invention is not limited to these Examples. The contents listed in Tables 1 to 12 are expressed in mass % unless otherwise specified. The gel patches of the Examples and Test Examples were prepared and their adhesion was measured as follows.

(Preparation method of mud patch)

The necessary ingredients were stirred and mixed for a predetermined time to obtain a paste, which was evenly spread on a release liner so that the paste weight per paste patch (140 mm x 100 mm) was 5 g, and then immediately laminated with a nonwoven fabric to prepare a paste patch.

[Comparative Example 1]

Temporal changes in the adhesion of conventional gel patches

(1) Test samples

The ingredients listed in Table 1 were stirred and mixed for a predetermined time to obtain a paste. The resulting paste was evenly spread on a release liner so that the paste mass per patch (140 mm x 100 mm) was 5 g. Immediately after spreading, a nonwoven fabric was further laminated to prepare a patch (Comparative Example 1).

[Table 1]

Ingredient name Content (mass %) Ethylene glycol salicylate 2.0 Menthol 1.0 gelatin 2.5 synthetic aluminum silicate 1.0 polyvinyl alcohol 2.5 Partially neutralized polyacrylic acid 4.0 concentrated glycerin 40.0 purified water 44.4 polyacrylic acid 2.0 Other ingredients margin total 100.0

(2) Test method

The obtained paste patch was applied to the knees of 10 test subjects, and the adhesion state of the paste patch after 0 (immediately after application), 2, 4, 8, and 12 hours was evaluated as an adhesion score according to the following evaluation criteria, and the average value was calculated.

Evaluation Benchmarks

100: No preparation peeling

80: Peeling occurs at the end of the preparation

60: 1/4 of the surface where the preparation adheres to the skin peels off

40: 1/3 of the surface where the preparation adheres to the skin peels off

20: 1/2 of the surface where the preparation adheres to the skin peels off

0: Preparation falls off

(3) Test results

As shown in Figure 1 , the adhesion of Comparative Example 1 decreased over time. The adhesion score of Comparative Example 1 was 100 immediately after application, but decreased by approximately 50% 12 hours after application.

[Example 1]

Temporal changes in adhesion of a patch containing a fully neutralized polyacrylic acid and a methyl acrylate/2-ethylhexyl acrylate copolymer emulsion

(1) Test samples

A poultice (Example 1) was prepared in the same manner as in Comparative Example 1, except that a completely neutralized polyacrylic acid (trade name: VISCOMATE F480SS, manufactured by Showa Denko K.K.) was used instead of the partially neutralized polyacrylic acid, and 16.7% by mass of a methyl acrylate/2-ethylhexyl acrylate copolymer resin emulsion (trade name: NIKASOL TS-620, manufactured by Nippon Carbide Industries, Ltd.), 30% by mass of concentrated glycerin, and 37.8% by mass of purified water were blended.

(2) Test method

The test was performed in the same manner as in [Comparative Example 1].

(3) Test results

As shown in FIG2 , the adhesion score of Comparative Example 2 was 90 immediately after application, but decreased by about 10% 12 hours after application.

[Example 2]

Temporal changes in adhesion of a patch containing a partially neutralized polyacrylic acid and a methyl acrylate/2-ethylhexyl acrylate copolymer emulsion

(1) Test samples

A paste patch was obtained in the same manner as in Comparative Example 1 except that 16.7% by mass of a methyl acrylate/2-ethylhexyl acrylate copolymer (trade name: NIKASOL TS-620, manufactured by Nippon Carbide Industries, Ltd.), 30% by mass of concentrated glycerin, and 37.8% by mass of purified water were mixed (Example 2).

(2) Test method

The test was performed in the same manner as in [Comparative Example 1].

(3) Test results

As shown in Figure 3, the adhesion score of Example 1 was 100 immediately after application, and decreased by about 9% 12 hours after application. The adhesion score of Example 1 did not decrease from 4 hours to 12 hours after application.

[Examples 1 and 2, Comparative Example 1]

The change in adhesion of the paste patch relative to the water content of the paste layer was measured as follows.

(1) Test samples

The test was conducted using Examples 1 and 2 and Comparative Example 1.

(2) Test method

The test was carried out in the same manner as in [Example 1], and the water content in the preparation was measured.

(3) Test results

As shown in Figure 4, the adhesion of Comparative Example 1 gradually decreased as the water content of the paste layer decreased. However, in Examples 1 and 2, no significant decrease in adhesion was observed regardless of the decrease in water content in the paste layer. This indicates that when the poly(methyl acrylate/2-ethylhexyl acrylate) emulsion is incorporated into the paste layer, the adhesion of the poly(methyl acrylate/2-ethylhexyl acrylate) emulsion is enhanced as the water content decreases.

[Comparative Examples 2, 3 and 4]

Changes in adhesion with changes in the concentrations of partially neutralized polyacrylic acid, poly(methyl acrylate/2-ethylhexyl acrylate) emulsion, and water in the gel patch were measured as follows.

(1) Test samples

The ingredients listed in Table 2 below were stirred and mixed for a predetermined time to obtain a paste. The resulting paste was evenly spread on a release liner so that the paste mass per patch (140 mm x 100 mm) was 5 g. Immediately after spreading, a nonwoven fabric was further laminated to prepare patch patches (Comparative Examples 2 to 4).

[Table 2]

Ingredient name Comparative Example 2 Comparative Example 3 Comparative Example 4 Partially neutralized polyacrylic acid 6.0 6.0 6.0 glycerin 30.0 29.0 20.0 NIKASOL TS-620 0.0 1.0 10.0 purified water 63.9 63.9 63.9 Other ingredients 0.1 0.1 0.1 total 100.0 100.0 100.0

(2) Test method

The results of applying the gel patches (Comparative Examples 2-4) for 12 hours were observed. Furthermore, the water content of each gel patch (Comparative Examples 2-4) was measured after a specified period of time had passed since application, and the concentrations of partially neutralized polyacrylic acid and NIKASOL TS-620 in the gel patches at each time point were calculated. The "adhesion" in Tables 3-5 indicates an adhesion score of 75 or higher, with an o-value and an x-value for less than 75.

(3) Test results

The results of the gel patches (Comparative Examples 2 to 4) are shown in Tables 3 to 5. The results in Tables 3 and 4 show that the gel patch adhesion score is maintained above 70 when the water content of the paste layer is 4 times or more based on the mass of the partially neutralized polyacrylic acid.

[Table 3]

[Table 4]

[Table 5]

[Examples 3 and 4, Comparative Example 5]

Relationship between the ratio of partially neutralized polyacrylic acid to methyl acrylate/2-ethylhexyl acrylate copolymer emulsion and peel strength after 8 hours

(1) Test samples

The ingredients listed in Table 6 below were stirred and mixed for a predetermined time to obtain a paste. The resulting paste was evenly spread on a release liner so that the paste mass per patch (140 mm x 100 mm) was 5 g. Immediately after spreading, a nonwoven fabric was further laminated to prepare a patch (Comparative Example 5, Examples 3 and 4).

[Table 6]

Ingredient name Comparative Example 5 Example 3 Example 4 Partially neutralized polyacrylic acid 3.00 3.00 3.00 polyacrylic acid 3.00 3.00 3.00 NIKASOL TS-620 5.00 10.00 20.00 concentrated glycerin 30.00 30.00 24.00 purified water 49.95 47.95 43.95 Other ingredients margin margin margin total 100.00 100.00 100.00

(2) Test method

The patch was cut into a 2cm × 7.5cm rectangle, the peeling liner was removed, and the patch was attached to a polypropylene plate and left to stand for 8 hours under a temperature of 25°C and a humidity of 60%. The patch was then peeled off at a speed of 30cm/minute and the load (N) was measured when the peeling starting end of the patch moved 20, 40, 60, 80, and 100mm. The results were repeated 3 times to calculate the mean value of the gained loads as the peel strength test value after 8 hours.

(3) Test results

As shown in Figure 5 , Examples 3 and 4 exhibited adhesion strength that was at least twice that of Comparative Example 5. Furthermore, even in a gel patch containing 5% of the partially neutralized polyacrylic acid based on the total mass of the gel patch, high adhesion was also exhibited by setting the mass of NIKASOL TS-620 to at least 2.5 times the mass of the partially neutralized polyacrylic acid.

[Example 5 and Comparative Example 6]

(1) Test samples

The ingredients listed in Table 7 were mixed to prepare a paste for a gel patch. The resulting paste was spread onto a plastic film (release liner) so that 7 g of the paste per gel patch (14 cm x 10 cm) was applied. A nonwoven fabric (support) was further laminated and cut into appropriate pieces to prepare gel patches of Comparative Example 6 and Example 5.

[Table 7]

Comparative Example 6 Example 5 Partially neutralized polyacrylic acid 3.0 3.0 polyacrylic acid 3.0 3.0 NIKASOL TS-620 6.0 7.5 gelatin 2.5 2.5 polyvinyl alcohol 2.5 2.5 concentrated glycerin 20.0 20.0 Ethylene glycol salicylate 2.0 2.0 purified water 57.45 55.95 Other ingredients 3.55 3.55 total 100 100

(2) Method of Test 1

The obtained paste patch was applied to the elbows of 15 test subjects, and the adhesion state of the paste patch was evaluated as an adhesion score based on the following evaluation criteria.

Evaluation Benchmarks

100: No preparation peeling

80: Peeling occurs at the end of the preparation

60: 1/4 of the surface where the preparation adheres to the skin peels off

40: 1/3 of the surface where the preparation adheres to the skin peels off

20: 1/2 of the surface where the preparation adheres to the skin peels off

0: Preparation falls off

(3) Results of Test 1

The results of the human skin adhesion test are shown in Table 8 and Figure 6. The adhesion score of the gel patch of Comparative Example 6 fell below 70 points 12 hours after application and below 50 points 18 hours after application. On the other hand, the adhesion score of the gel patch of Example 5 remained approximately 70 points even 24 hours after application.

[Table 8]

Elapsed time [hr] Comparative Example 6 Example 5 0 97 95 4 87 91 12 69 83 18 49 75 twenty four 43 69

(4) Method of Test 2

The gel patches of Comparative Example 6 and Example 5 were left at room temperature (temperature: 25°C, relative humidity: 60%) with the paste layer in contact with a laboratory table, and the changes in the gel patches' mass over time were examined.

(5) Results of Test 2

The measurement results of the total mass of the gel patches of Comparative Example 6 and Example 5 are shown in Table 9. In all of them, the mass continued to decrease at substantially the same rate.

[Table 9]

Elapsed time [hr] Comparative Example 6 Example 5 0 6.81 6.85 4 4.61 4.70 1.8 3.46 3.64 twenty four 3.45 3.63

The time-dependent changes in the mass of the components of the gel patches of Comparative Example 6 and Example 5 are shown in Tables 10 and 11, respectively. The results for the gel patch of Example 5 4 hours after application indicate that the mass of purified water was approximately 7.5 times that of the partially neutralized polyacrylic acid, and that adhesion persisted for 20 hours thereafter. Furthermore, the results for the gel patch of Example 5 18 hours after application indicate that the mass of purified water was approximately 2 times that of the partially neutralized polyacrylic acid, and that adhesion persisted for 6 hours thereafter. Meanwhile, the results for the gel patch of Comparative Example 6 indicate that, at a ratio of 1:2 between the partially neutralized polyacrylic acid and NIKASOL TS-620, adhesion decreased with decreasing water content.

[Table 10]

[Table 11]

[Examples 6 to 13]

The ingredients listed in Table 12 were mixed to prepare a paste for a gel patch. The paste was spread on a woven cloth made of polyethylene terephthalate to a mass of 500 g/m ² to obtain gel patches (Examples 6 to 13). The gel patches showed very good adhesion even after 8 hours of application.

In addition, for Examples 6, 10, and 13, paste patches were prepared having a paste layer of ³ g (214 g/m ² ), 5 g (357 g/m ² ), 6 g (429 g/m ² ), 7 g (500 g/m ² ), or 14 g (1000 g/m ² ) per application area of 140 cm 2 .

The gel patches of Examples 1 to 13 had a pH of 5, and no water seepage from the paste layer to the support was observed. Similarly, even when the gel patches were prepared at a pH of 6.5, no water seepage was observed.

Furthermore, paste patches were prepared respectively having a paste layer with the same composition as in Examples 1 to 13 and using a woven fabric, non-woven fabric or foam sheet with a unit mass of 100 g/m ² as a support.

Claims (12)

1. A mud-applying agent having a paste layer on a support, wherein, The aforementioned paste layer is obtained by mixing at least a polyacrylic acid neutralizer, a poly(methyl acrylate/2-ethylhexyl acrylate) emulsion at a mass ratio of more than 2.5 times that of the neutralizer, water, and polyacrylic acid. The evaporation residue of the above-mentioned poly(methyl acrylate/2-ethylhexyl acrylate) emulsion after heating at a temperature above the boiling point of the medium is 57-61%. The content of polyacrylic acid neutralizer is 1-6% by mass, based on the total mass of the paste layer. The content of polyacrylic acid is based on the total mass of the paste layer, ranging from 1% to 5% by mass. 2. The mud-applying agent according to claim 1, wherein the poly(methyl acrylate/2-ethylhexyl acrylate) emulsion contains poly(oxyethylene) nonylphenyl ether. 3. The mud-applying agent according to claim 1 or 2, wherein the above-mentioned polyacrylic acid neutralizer is a partially neutralized polyacrylic acid compound. 4. The mud-applying agent according to claim 1 or 2, wherein the water content in the paste layer is greater than the mass of the poly(methyl acrylate/2-ethylhexyl acrylate) emulsion. 5. The mud-applying agent according to claim 1 or 2, wherein the water content in the paste layer is more than four times the mass of the polyacrylic acid neutralizer. 6. The mud-applying agent according to claim 1 or 2, wherein the polyacrylic acid neutralizer, poly(methyl acrylate/2-ethylhexyl acrylate) emulsion and water are mixed in a mass ratio of polyacrylic acid neutralizer: poly(methyl acrylate/2-ethylhexyl acrylate) emulsion: water = 1:2.5 to 7:5 to 16. 7. The mud application agent according to claim 1 or 2, wherein the polyacrylic acid neutralizer, poly(methyl acrylate/2-ethylhexyl acrylate) emulsion and water are mixed in a mass ratio of polyacrylic acid neutralizer: poly(methyl acrylate/2-ethylhexyl acrylate) emulsion: water = 1:2.5 to 7:7 to 16. 8. The mud-applying agent according to claim 1 or 2, wherein the water content in the paste layer is 20-60% by mass based on the total mass of the paste layer. 9. The mud-applying agent according to claim 1 or 2, wherein the content of the above-mentioned polyacrylic acid neutralizer in the above-mentioned paste layer is 1 to 6% by mass based on the total mass of the above-mentioned paste layer. 10. The mud-applying agent according to claim 1 or 2, wherein the mass of the paste layer is 214-1000 g/ ^m² . 11. The mud-applying agent according to claim 1 or 2, wherein the adhesion is based on the poly(methyl acrylate/2-ethylhexyl acrylate) in the poly(methyl acrylate/2-ethylhexyl acrylate) emulsion and the polyacrylic acid neutralizer. During application, the adhesion of the above-mentioned polyacrylic acid neutralizer is greater than that of the above-mentioned poly(methyl acrylate/2-ethylhexyl acrylate). As the water content of the above-mentioned paste layer decreases, the adhesion of the above-mentioned poly(methyl acrylate/2-ethylhexyl acrylate) gradually becomes greater than that of the above-mentioned polyacrylic acid neutralizer. 12. A method for manufacturing a mud-applying agent, wherein the mud-applying agent has a paste layer on a support and maintains adhesion even when the water content is reduced, wherein... The above-mentioned paste layer is obtained by containing at least 2.5 times the mass of poly(methyl acrylate/2-ethylhexyl acrylate) emulsion in the polyacrylic acid, water and polyacrylic acid neutralizer.