JP2017145328A - Pressure sensitive adhesive for skin patch and sheet for skin patch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure sensitive adhesive and an adhesive sheet which achieve both adhesiveness to the skin and peelability from the skin at high levels and suppress an adhesive deposit in the present invention.SOLUTION: A pressure sensitive adhesive for skin patch includes an acrylic polymer which is an emulsion polymer of a monomer mixture including an acrylic acid alkyl ester (A) including an alkyl chain having 4 to 7 carbon atoms, an acrylic acid alkyl ester (B) including an alkyl chain having 8 to 12 carbon atoms, and acrylic acid. In the pressure sensitive adhesive for skin patch, the monomer mixture includes 3 to 7 mass% of acrylic acid, and a mass ratio between the acrylic acid alkyl ester (A) and the acrylic acid alkyl ester (B) is (A)/(B)=65/35 to 25/75.SELECTED DRAWING: None

Description

  The present invention relates to an adhesive that is directly applied to the skin.

  In recent years, patches such as poultices and plasters have been widely used for transdermal administration of pharmaceuticals in the medical field, and adhesives have been widely used for patches. There are cases where electrodes are attached to the skin for low-frequency treatment, measurement of electroencephalograms or electrocardiograms, etc. In this case, an adhesive is sometimes used. On the other hand, in the cosmetics field, an adhesive is used for a portion that directly touches the skin, such as for eye makeup, prevention of wig slippage, and creation of wrinkles in special makeup. These adhesives for skin application are required to have sufficient adhesive strength when used, and that no adhesive remains on the skin side when peeled.

  Patent Document 1 discloses a medical pressure-sensitive adhesive composition containing an acrylic copolymer, a drug having a carboxyl group, and a base.

  Patent Document 2 discloses a monomer comprising methyl acrylate, 60 to 90% by weight of (meth) acrylic acid ester having an alkyl group having 4 to 12 carbon atoms, and 2 to 15% by weight of acrylic acid and / or methacrylic acid. A copolymer emulsion for pressure-sensitive adhesive for human body use, comprising a copolymer obtained by emulsion copolymerization of a mixture is disclosed.

  Patent Document 3 discloses an adhesive for false eyelashes characterized by containing water, 2-ethylhexyl acrylate, methyl methacrylate, ethyl acrylate, and an acrylic copolymer composed of methacrylic acid. ing.

JP 2007-063384 A WO2011 / 129269 JP 2009-40718 A

  However, conventional pressure-sensitive adhesives have low levels of adhesion and peelability to the skin, and the level of adhesive residue when peeling the pressure-sensitive adhesive sheet is low.

  An object of the present invention is to provide a pressure-sensitive adhesive and a pressure-sensitive adhesive sheet in which adhesiveness to the skin and peelability are compatible at a high level and adhesive residue is suppressed.

The adhesive for skin application of the present invention comprises an acrylic acid alkyl ester (A) having a C 4-7 alkyl chain, an acrylic acid alkyl ester (B) having a C 8-12 alkyl chain, and acrylic acid. An acrylic polymer that is an emulsion polymer of a monomer mixture containing
Containing 3 to 7% by mass of acrylic acid in the monomer mixture;
The mass ratio of the alkyl acrylate ester (A) to the alkyl acrylate ester (B) is (A) / (B) = 65/35 to 25/75.

  According to the present invention having the above-described configuration, the acrylic polymer containing the acrylic acid alkyl ester (A) and the acrylic acid alkyl ester (B) in an appropriate ratio and containing a relatively large amount of acrylic acid is included. In addition to being able to achieve a high level of adhesiveness and peelability to the skin and suppressing adhesive residue, an unexpected effect of improving the mechanical stability of the adhesive was obtained.

  According to the present invention, it is possible to provide a pressure-sensitive adhesive and a pressure-sensitive adhesive sheet in which adhesiveness to the skin and peelability are compatible at a high level and adhesive residue is suppressed.

The adhesive for skin application of the present invention comprises an acrylic acid alkyl ester (A) having a C 4-7 alkyl chain, an acrylic acid alkyl ester (B) having a C 8-12 alkyl chain, and acrylic acid. An acrylic polymer that is an emulsion polymer of a monomer mixture containing
Containing 3 to 7% by mass of acrylic acid in the monomer mixture;
The mass ratio of the alkyl acrylate ester (A) to the alkyl acrylate ester (B) is (A) / (B) = 65/35 to 25/75. In the present invention, the monomer is an ethylenically unsaturated double bond-containing monomer.

  The acrylic polymer used in the present invention includes an acrylic acid alkyl ester (A) having an alkyl chain having 4 to 7 carbon atoms, an acrylic acid alkyl ester (B) having an alkyl chain having 8 to 12 carbon atoms, and acrylic acid. It is an emulsion polymer of a monomer mixture.

  Acrylic acid alkyl ester (A) having a C 4-7 alkyl chain (hereinafter referred to as acrylic acid alkyl ester (A)) is, for example, normal butyl acrylate, isobutyl acrylate, tertiary butyl acrylate, normal pentyl acrylate, or normal hexyl. Examples include acrylate, 2-ethylbutyl acrylate, 2-methylpentyl acrylate, and 1,3-dimethylbutyl acrylate. Among these, normal butyl acrylate is preferable.

  Acrylic acid alkyl ester (B) having an alkyl chain of 8 to 12 carbon atoms (hereinafter referred to as acrylic acid alkyl ester (B)) includes normal octyl acrylate, 2-ethylhexyl acrylate, 6-methylpeptyl acrylate, and normal nonyl acrylate. 6-methyloctyl acrylate, normal decyl acrylate, normal methyl nonyl acrylate, normal undecyl acrylate, lauryl acrylate, 7-methyl octyl acrylate, 8-methyl nonyl acrylate, 8-methyl decyl acrylate, 9-methyl decyl acrylate, 9- Examples thereof include methyl undecyl acrylate, 10-methyl undecyl acrylate, and the like. Among these, 2-ethylhexyl acrylate is preferable.

  In the present invention, the mass ratio of the acrylic acid alkyl ester (A) and the acrylic acid alkyl ester (B) is (A) / (B) = 65 / 35-25 / 75, preferably 50 / 50-25 / 75. 40/60 to 30/70 are more preferable. When the mass ratio is within an appropriate range, both adhesiveness and peelability can be achieved at a high level.

  The total amount of the acrylic acid alkyl ester (A) and the acrylic acid alkyl ester (B) is preferably 90 to 97% by mass, more preferably 93 to 97% by mass in 100% by mass of the monomer mixture.

  The acrylic acid used in the present invention contains 3 to 7% by mass in 100% by mass of the monomer mixture, and is preferably 4 to 6% by mass. When acrylic acid is contained in an appropriate range, in addition to good adhesion, the mechanical stability of the pressure-sensitive adhesive is further improved.

  The monomer mixture can include (meth) acrylic acid alkyl ester (A), (meth) acrylic acid alkyl ester (B), and other monomers other than acrylic acid.

Other monomers include methyl (meth) acrylate, ethyl (meth) acrylate, normal propyl (meth) acrylate, isopropyl (meth) acrylate, normal butyl methacrylate, isobutyl methacrylate, tertiary butyl methacrylate, normal pentyl methacrylate, normal hexyl methacrylate, 2-ethylbutyl methacrylate, 2-methylpentyl methacrylate, 1,3-dimethylbutyl methacrylate, normal octyl methacrylate, 2-ethylhexyl methacrylate, 6-methylpeptyl methacrylate, normal nonyl methacrylate, 6-methyloctyl methacrylate, normal decyl methacrylate, Normal methyl nonyl methacrylate, normal undecite methacrylate, (Meth) acrylic acid alkyl esters such as ril methacrylate, 7-methyloctyl methacrylate, 8-methylnonyl methacrylate, 8-methyldecyl methacrylate, 9-methyldecyl methacrylate, 9-methylundecyl methacrylate, 10-methylundecyl methacrylate, etc. Mer;
Acidic group-containing ethylenic monomers such as methacrylic acid, crotonic acid, isocrotonic acid, paravinylbenzenesulfonic acid, 2-acrylamidopropanesulfonic acid, 3-vinylsalicylic acid, 3-vinylacetylsalicylic acid;
Styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, m-methylstyrene, vinylnaphthalene, benzyl acrylate, benzyl methacrylate, phenoxyethyl acrylate, phenoxyethyl methacrylate, phenoxydiethylene glycol acrylate, phenoxydiethylene glycol methacrylate, phenoxytetraethylene Aromatic-containing monomers such as glycol acrylate, phenoxytetraethylene glycol methacrylate, phenoxyhexaethylene glycol acrylate, phenoxyhexaethylene glycol methacrylate, phenyl acrylate, and phenyl methacrylate;
Alicyclic alkyl group-containing ethylenically unsaturated monomers such as cyclohexyl (meth) acrylate and isobornyl (meth) acrylate;
(Meth) acrylamide, N-methoxymethyl- (meth) acrylamide, N-ethoxymethyl- (meth) acrylamide, N-propoxymethyl- (meth) acrylamide, N-butoxymethyl- (meth) acrylamide, N-pentoxymethyl -(Meth) acrylamide, N, N-di (methoxymethyl) acrylamide, N-ethoxymethyl-N-methoxymethylmethacrylamide, N, N-di (ethoxymethyl) acrylamide, N-ethoxymethyl-N-propoxymethylmeta Acrylamide, N, N-di (propoxymethyl) acrylamide, N-butoxymethyl-N- (propoxymethyl) methacrylamide, N, N-di (butoxymethyl) acrylamide, N-butoxymethyl-N- (methoxymethyl) meta Acrylic net N, N-di (pentoxymethyl) acrylamide, N-methoxymethyl-N- (pentoxymethyl) methacrylamide, N, N-dimethylaminopropylacrylamide, N, N-diethylaminopropylacrylamide, N, N-dimethyl Amide group-containing ethylenically unsaturated monomers such as acrylamide and N, N-diethylacrylamide;
2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, glycerol mono (meth) acrylate, 4-hydroxyvinylbenzene, 1-ethynyl-1-cyclohexanol, allyl Hydroxyl group-containing ethylenically unsaturated monomers such as alcohol;
Allyl (meth) acrylate, 1-methylallyl (meth) acrylate, 2-methylallyl (meth) acrylate, 1-butenyl (meth) acrylate, 2-butenyl (meth) acrylate, 3-butenyl (meth) acrylate, 1,3- Methyl-3-butenyl (meth) acrylate, 2-chloroallyl (meth) acrylate, 3-chloroallyl (meth) acrylate, o-allylphenyl (meth) acrylate, 2- (allyloxy) ethyl (meth) acrylate, allyl lactyl (meth) Acrylate, citronellyl (meth) acrylate, geranyl (meth) acrylate, rosinyl (meth) acrylate, cinnamyl (meth) acrylate, diallyl maleate, diallyl itaconic acid, vinyl (meth) acrylate, vinyl crotonic acid Vinyl oleate, vinyl linolenate, 2- (2′-vinyloxyethoxy) ethyl (meth) acrylate, ethylene glycol di (meth) acrylate, triethylene glycol (meth) acrylate, tetraethylene glycol (meth) acrylate, trimethylol Propane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, 1,1,1-trishydroxymethylethane diacrylate, 1,1,1-trishydroxymethylethane triacrylate, 1,1,1-trishydroxymethyl Ethylenically unsaturated monomers having two or more ethylenically unsaturated groups such as propane triacrylate, divinylbenzene, divinyl adipate, diallyl isophthalate, diallyl phthalate, diallyl maleate;
Epoxy group-containing ethylenically unsaturated monomers such as glycidyl (meth) acrylate and 3,4-epoxycyclohexyl (meth) acrylate;
γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-methacryloxypropyltributoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-acryloxy Propyltrimethoxysilane, γ-acryloxypropyltriethoxysilane, γ-acryloxypropylmethyldimethoxysilane, γ-methacryloxymethyltrimethoxysilane, γ-acryloxymethyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane , Alkoxysilyl group-containing ethylenically unsaturated monomers such as vinyltributoxysilane and vinylmethyldimethoxysilane;
Other monomers can be used alone or in combination of two or more.
It is preferable that another monomer contains 20 mass% or less in 100 mass% of monomer mixtures. In addition, when a (meth) acrylic acid alkyl ester having an alkyl chain having 1 to 2 carbon atoms is used, mechanical stability tends to be lowered.

  The emulsion polymerization is preferably performed in the presence of a monomer mixture and at least one of a surfactant and a protective colloid. The total amount of the surfactant and the protective colloid is preferably 0.1 to 10 parts by mass, more preferably 0.5 to 5.0 parts by mass with respect to 100 parts by mass of the monomer mixture. When an appropriate amount of a surfactant and a protective colloid is used, the polymerization stability is improved and the skin is hardly adversely affected.

The surfactant is preferably an anion, a cation or a nonion as an ionic species, and more preferably an anion or a nonion. The surfactant is preferably a reactive emulsifier having an ethylenically unsaturated double bond and a non-reactive emulsifier not having the same.
That is, in the present invention, the surfactant can be appropriately selected from a reactive nonionic surfactant, a nonreactive nonionic surfactant, a reactive anionic surfactant, and a nonreactive anionic surfactant. .

  Examples of the reactive nonionic surfactant include compounds having a main skeleton of alkyl ether, alkylphenyl ether, alkylphenyl ester and the like and having an ethylenically unsaturated double bond.

  Non-reactive nonionic surfactants include, for example, polyoxyethylene alkylphenyls such as polyoxyethylene lauryl ether and polyoxyethylene stearyl ether, polyoxyethylene alkylphenyls such as polyoxyethylene octylphenyl ether and polyoxyethylene nonylphenyl ether Sorbitan higher fatty acid esters such as ether, sorbitan monolaurate, sorbitan monostearate, sorbitan trioleate, polyoxyethylene sorbitan higher fatty acid esters such as polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monostearate, polyoxyethylene Polyoxyethylene higher fatty acid esters such as monolaurate and polyoxyethylene monostearate, oleic acid Glyceride, glycerin higher fatty acid esters such as stearic acid monoglyceride, polyoxyethylene polyoxypropylene block copolymers, polyoxyethylene distyrenated phenyl ether and the like.

  A reactive anionic surfactant is a compound having an ethylenically unsaturated double bond, for example, a main skeleton having sulfosuccinic acid ester, alkyl ether, alkylphenyl ether, alkylphenyl ester, (meth) acrylate sulfate ester, phosphate ester, etc. Is preferred.

  Non-reactive anionic surfactants include, for example, higher fatty acid salts such as sodium oleate, alkylaryl sulfonates such as dodecylbenzene sulfonic acid, alkyl sulfate esters such as sodium lauryl sulfate, polyoxyethylene lauryl ether sodium sulfate, etc. Polyoxyethylene alkyl ether sulfates, sodium monooctylsulfosuccinate, sodium dioctylsulfosuccinate, polyoxyethylene lauryl sodium sulfosuccinate and derivatives thereof, polyoxyethylene distyrenated phenyl ether sulfate Etc.

  More preferably, the surfactant is used in combination with an anionic surfactant and a nonionic surfactant. The anionic surfactant is preferably used in an amount of 0.5 to 1.5 parts by mass with respect to 100 parts by mass of the monomer mixture. When an appropriate amount of an anionic surfactant is used, the adhesive strength is further improved. The nonionic surfactant is preferably used in an amount of 1 to 2 parts by mass with respect to 100 parts by mass of the monomer mixture. When an appropriate amount of nonionic surfactant is used, adhesive residue can be further suppressed.

  The emulsion polymerization is preferably performed in the presence of a radical polymerization initiator (hereinafter referred to as a polymerization initiator). As the polymerization initiator, a known oil-soluble polymerization initiator or water-soluble polymerization initiator can be used.

Examples of the oil-soluble polymerization initiator include benzoyl peroxide, tertiary butyloxybenzoate, tertiary butyl hydroperoxide, tertiary butyl peroxy-2-ethylhexanoate, tertiary butyl peroxy-3,5,5. , Trimethylhexanoate, ditertiary butyl peroxide, cumene hydroperoxide, organic peroxides such as p-menthane hydroperoxide, 2,2′-azobisisobutyronitrile, 2,2′-azobis- Examples include azobis compounds such as 2,4-dimethylvaleronitrile, 2,2 ″ -azobis (4-methoxy-2,4-dimethylvaleronitrile), and 1,1′-azobiscyclohexane-1-carbonitrile. .
Examples of the water-soluble polymerization initiator include ammonium persulfate, sodium persulfate, potassium persulfate, hydrogen peroxide, and 2,2′-azobis (2-methylpropionamidine) dihydrochloride.

In emulsion polymerization, a reducing agent can be used in combination with a polymerization initiator (collectively referred to as a redox initiator). Emulsion polymerization is accelerated by the redox initiator. Examples of the reducing agent include reducing organic compounds such as metal salts such as ascorbic acid, erythorbic acid, tartaric acid, citric acid, glucose, formaldehyde sulfoxylate; sodium sulfite, sodium bisulfite, sodium metabisulfite (SMBS), hyposulfite Reducing inorganic compounds such as sodium; ferrous chloride, Rongalite and the like.
In the present invention, the polymerization initiator is preferably a water-soluble polymerization initiator.

  It is preferable that a polymerization initiator uses 0.03-5 mass parts with respect to 100 mass parts of monomer mixtures. The reducing agent is preferably used in an amount of 0.01 to 2.5 parts by mass with respect to 100 parts by mass of the monomer mixture.

In the emulsion polymerization, a buffer, a chain transfer agent, a basic compound and the like can be used as necessary. Examples of the buffer include sodium acetate, sodium citrate, sodium bicarbonate and the like.
Examples of the chain transfer agent include octyl mercaptan, tertiary decyl mercaptan, lauryl mercaptan, stearyl mercaptan, 2-ethylhexyl mercaptoacetate, octyl mercaptoacetate, 2-ethylhexyl mercaptopropionate, octyl mercaptopropionate, and the like.
Basic compounds are used for neutralization, for example, alkylamines such as trimethylamine, triethylamine, and butylamine; alcohol amines such as 2-dimethylaminoethanol, diethylaminoethanol, diethanolamine, triethanolamine, and aminomethylpropanol; morpholine, ammonia, and the like. It is done.

  The acrylic polymer is an emulsion polymer and can be said to be a polymer particle. The average particle size of the polymer particles is preferably 50 to 500 nm, and more preferably 150 to 400 nm. When the average particle diameter is in an appropriate range, the water resistance of the pressure-sensitive adhesive is improved, and the adhesiveness is hardly lowered even by body fluids such as sweat and tears. The average particle diameter is a D50 average particle diameter using a dynamic light scattering measurement method. As an example of the measurement method, a diluted solution is prepared by diluting an aqueous dispersion of polymer particles 500 times with water. It can be measured with Nanotrac (Nikkiso Co., Ltd.) using about 5 mL of diluent.

  The gel fraction of the acrylic polymer is preferably 70 to 95% by mass, more preferably 75 to 90% by mass. When the gel fraction is in an appropriate range, it becomes easy to achieve both adhesion and peelability at a high level. The gel fraction can be adjusted by the monomer composition, the polymerization initiator type and amount, and the chain transfer agent type and amount. In addition, a gel fraction is a ratio of the insoluble content at the time of 50 degreeC 24 hours in ethyl acetate among the non volatile matters of an acrylic polymer.

The adhesive for skin application of the present invention can contain additives such as extender pigments, antifoaming agents, preservatives, and solvents as optional components, as long as the problem can be solved.
Examples of extender pigments include talc, silica, calcium carbonate, barium sulfate, titanium oxide, diatomaceous earth (white carbon), and cellulose powder.

  Examples of the solvent include ethanol, isopropyl alcohol, propylene glycol, glycerin and the like from the viewpoint of safety.

The skin sticking sheet of the present invention includes a base material and an adhesive layer formed from a skin sticking adhesive.
The substrate is, for example, a plastic film (polyethylene, polypropylene, ethylene / vinyl acetate copolymer, polystyrene, polyester, polyvinyl chloride, polyvinylidene chloride, polyurethane, polyamide, etc.), porous substrate (woven fabric, knitted fabric, non-woven fabric) Paper), metal foil, and laminates thereof.
Although the thickness of a base material is not specifically limited, Usually, it is 20-1000 micrometers, and 25-500 micrometers is preferable from a viewpoint of having a softness | flexibility and intensity | strength.

  The pressure-sensitive adhesive layer is formed by applying a pressure-sensitive adhesive on a substrate. Or the method of transferring the adhesive layer formed by applying an adhesive on a peeling sheet to a base material is common. In addition, it is normal to stick a release sheet on the surface which does not contact the base material of an adhesive layer, and to store it.

Examples of the adhesive coating method include known coating methods such as spin coating, spray coating, bar coating, knife coating, roll coating, roll knife coating, blade coating, die coating, and gravure coating. You can use the method. Moreover, it is also preferable to perform a drying process at the time of coating. For the drying step, a known device such as a hot air oven, an electric oven, an infrared heater or the like can be used.
The thickness of the pressure-sensitive adhesive layer is usually about 10 to 100 g / m ^{2 and} more preferably ²⁰ to 50 g / m ² from the viewpoint of achieving both adhesiveness and peelability.

  The adhesive for skin application and the sheet for skin application of the present invention include, for example, a medical adhesive such as an electrode adhesive, a poultice, a plaster, and a medical adhesive sheet, for eye makeup, for preventing wig slippage, and special makeup. It can be used for various applications such as a cosmetic pressure-sensitive adhesive for making wrinkles and a pressure-sensitive adhesive sheet for makeup.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, a following example does not restrict | limit the right range of this invention at all. In the examples, “part” represents “part by mass” and “%” represents “% by mass”. Moreover, the compounding quantity in a table | surface is a mass part.

<Example 1>
As (meth) acrylic acid alkyl ester (A) having an alkyl chain having 4 to 7 carbon atoms, 36.8 parts of normal butyl acrylate and (meth) acrylic acid alkyl ester (B) having an alkyl chain having 8 to 12 carbon atoms 2-ethylhexyl acrylate 59.0 parts, acrylic acid 4.2 parts, anionic surfactant Emul O (sodium lauryl sulfate manufactured by Kao Corporation) as a surfactant, nonionic surfactant Emulgen 123P ( Pre-emulsion prepared by emulsifying a mixed solution of 1.6 parts of polyoxyethylene lauryl ether (produced by Kao Corporation), 0.05 parts of octyl thioglycolate as a chain transfer agent, and 28.2 parts of ion-exchanged water with a blade-type disper. Was charged into the dropping tank.
Separately, 1.55 parts of an initiator aqueous solution prepared by dissolving 0.44 parts of potassium persulfate as a polymerization initiator in 1.32 parts of ion-exchanged water was charged into an initiator tank.
Separately, a 5-necked flask equipped with a reflux condenser, a stirrer, a thermometer, a nitrogen inlet tube, and a raw material inlet was used as a reaction vessel, and 25.7 parts of ion-exchanged water was charged into the reaction vessel. Next, the liquid temperature was heated to 80 ° C. with stirring in a nitrogen atmosphere. Next, 0.21 part of the initiator aqueous solution was charged into the reaction vessel from the initiator tank, and then the pre-emulsion and the initiator aqueous solution were continuously dropped from the initiator tank over 3 hours, and the liquid temperature was adjusted. Emulsion polymerization was performed while maintaining the temperature at about 80 ° C. After completion of dropping, the liquid temperature was kept at 80 ° C. for 3 hours, and emulsion polymerization was continued. Then, it cooled to 50 degreeC and ion-exchange water was added and the non volatile matter was adjusted to 40%. Thereafter, the solution was filtered through a 180 mesh polyester filter cloth to obtain an adhesive. There was no aggregate remaining on the filter cloth, and the polymerization stability was good.
About the obtained adhesive, the glass transition point (Tg), D50 average particle diameter, and gel fraction were measured in the following ways.

<Tg>
It measured using DSC (Differential scanning calorimeter TA Instruments company make). Specifically, about 2 mg of a sample was weighed on an aluminum pan, the aluminum pan was set on a DSC measurement holder, and an endothermic peak obtained under a temperature rising condition of 5 ° C./min was read and used as Tg.

<D50 average particle size>
It measured by water dilution using Nanotrac Wave-EX150 (made by Nikkiso Co., Ltd.).

<Gel fraction>
The obtained pressure-sensitive adhesive was applied to a polyethylene terephthalate (PET) film and dried, and after being immersed in ethyl acetate and allowed to stand at 50 ° C. for 24 hours, insolubles were taken out and dried. The mass (W2) was measured and determined as follows.
Gel fraction = (W2 / W1) × 100

<Examples 2 to 17 and Comparative Examples 1 to 7>
Except having changed into the compounding composition shown in Table 1, it carried out by the method similar to Example 1, and obtained the adhesive of Examples 2-19 and Comparative Examples 1-7, respectively.

Abbreviations in the table are as follows.
nBA: normal butyl acrylate iBA: isobutyl acrylate tBA: tertiary butyl acrylate nHA: normal hexyl acrylate 2EHA: 2-ethylhexyl acrylate nOA: normal octyl acrylate LA: lauryl acrylate AA: acrylic acid MAA: methacrylic acid nBMA: normal butyl methacrylate 2HEMA: 2-hydroxyethyl methacrylate OTG: octyl thioglycolate IPA: isopropyl alcohol

<Compounding stability>
20 parts by mass of isopropyl alcohol was added while stirring 100 parts by mass of the obtained pressure-sensitive adhesive with a blade-type disper, and after stirring for 1 minute, the presence or absence of aggregates was visually observed to evaluate the blending stability. The practical standard is 4 points or more.
5: No aggregate 4: Small amount of aggregate 3: Medium amount of aggregate 2: Large amount of aggregate 1: Gelation of the entire system

<Machine stability>
Using a Maron mechanical stability tester (AB-802, manufactured by Tester Sangyo Co., Ltd.), 50 g of the obtained adhesive was applied to a tester under the conditions of a load of 10 kg and 1000 rpm for 5 minutes to measure the mechanical stability. Evaluation showed the aggregate generation amount with respect to the non volatile matter mass of an adhesive in mass%. It means that mechanical stability is so favorable that the numerical value of this mass% is low. The practical standard is 1 g or less.

The obtained pressure-sensitive adhesive was applied to a 25 μm PET film (Luminer S10, manufactured by Toray Industries, Inc.) with an applicator so that the dry mass was 25 g / m ^2, and dried at 105 ° C. for 2 minutes to form a NS separator Z (inside This product was made by PAX. This was cut into a circular shape with a diameter of 1 cm to remove the release film to make a patch, and this patch was affixed to the inner side of the upper arms of 5 subjects for 8 hours. After 8 hours, it was peeled off after testing whether the index finger was used to shift the patch. The evaluation criteria of adhesiveness and peelability at this time are as follows. In addition, as for all the scores, the average score of three people excluding the highest score and the lowest score among the five people was used as the evaluation result. All practical levels are 2.5 or more.

<Adhesiveness>
5: It adheres stably for 8 hours, and the patch cannot be moved with fingers.
4: Adhering stably for 8 hours, but using strong force, the patch moves with your fingers.
3: Adhering stably for 8 hours, but the patch moves with a finger with a weak force.
2: Peel off between 4 to 8 hours.
1: It peels between 4 hours immediately after sticking.

<Peelability>
5: No adhesive residue on the skin and no pain.
4: There is no adhesive residue on the skin, but there is slight pain.
3: There is no adhesive residue on the skin, but it hurts considerably.
2: The adhesive residue on the skin is 0 to 30% of the patch area.
1: The adhesive residue on the skin is 30% or more of the patch area.

  From the result of Table 2, Examples 1-17 have favorable mixing | blending stability and mechanical stability, and are making adhesiveness and peelability compatible. Therefore, it is an excellent adhesive for skin patch that cannot be obtained in Comparative Examples 1-7.

Claims (4)

Acrylic acid alkyl ester (A) having an alkyl chain having 4 to 7 carbon atoms, acrylic acid alkyl ester (B) having an alkyl chain having 8 to 12 carbon atoms, and acrylic that is an emulsion polymer of a monomer mixture containing acrylic acid Containing a polymer,
Containing 3 to 7% by mass of acrylic acid in the monomer mixture;
The adhesive for skin sticking whose mass ratio of the said acrylic acid alkylester (A) and the said acrylic acid alkylester (B) is (A) / (B) = 65 / 35-25 / 75.   The adhesive for skin patches according to claim 1, wherein a mass ratio of the acrylic acid alkyl ester (A) to the acrylic acid alkyl ester (B) is (A) / (B) = 50/50 to 25/75. Agent.   Furthermore, the adhesive for skin patches of Claim 1 or 2 containing an anionic emulsifier and a nonionic emulsifier. The sheet | seat for skin sticking provided with the base material and the adhesive layer formed from the adhesive agent for skin sticking in any one of Claims 1-3.