Hydrocolloid-type pressure-sensitive adhesive composition, article comprising pressure-sensitive adhesive layer made of hydrocolloid-type pressure-sensitive adhesive composition, and wound dressing

Abstract

To provide a hydrocolloid type adhesive composition having an adhesive property and water absorption property for actual use, having high water vapor permeation ratio, and reducing pain in peeling from a living body, an article comprising an adhesive layer formed of a hydrocolloid type adhesive composition, and a wound covering material.SOLUTION: There is provided a hydrocolloid type adhesive composition including, an acrylic block copolymer and an absorbent (Z).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a hydrocolloid pressure-sensitive adhesive composition, a hydrocolloid pressure-sensitive adhesive contact The present invention relates to an article and a wound dressing comprising an adhesive layer made of an adhesive composition. [Background technology]

[0002] Acrylic block copolymers or compositions containing acrylic block copolymers have been studied for use as adhesives due to their excellent adhesive properties. For example, adhesive compositions combining two specific acrylic triblock copolymers have been studied in order to obtain adhesives with little bleeding and excellent transparency, adhesive properties, and processability (see Patent Document 1).

[0003] Adhesives are used in a variety of applications, including biological surface adhesive materials (e.g., wound dressings) that contain an adhesive layer made of an adhesive on at least a portion of the surface that comes into contact with a biological surface such as skin. These biological surface adhesive materials are required to have properties different from those used in other applications, such as conformability to the biological surface. For example, adhesive compositions containing a specific acrylic triblock copolymer and a specific diblock copolymer have been investigated, primarily for the purpose of adhering to biological surfaces (see Patent Document 2).

[0004] Furthermore, hydrocolloid adhesives have become increasingly important in recent years because they have adhesive properties themselves, absorb wound secretions that exude during the healing process, and maintain a moist state, thereby exhibiting good wound healing effects.

[0005] In general, hydrocolloid pressure-sensitive adhesives have hydrophilic colloid particles (water absorbents) dispersed in a matrix made of thermoplastic rubber, and most of them are prepared so that they can absorb about 3 to 5 times their own weight in water or exudate from a wound site in a certain period of time. Various rubber components have been investigated and proposed so that they can maintain the desired adhesiveness even after absorbing water, etc. (see Patent Documents 3 and 4). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2018-003035 [Patent Document 2] Japanese Patent Publication No. 2020-023720 [Patent Document 3] Special Publication No. 2002-512295 [Patent Document 4] JP 2015-188500 A Summary of the Invention [Problem to be solved by the invention]

[0007] Although these hydrocolloid-type pressure-sensitive adhesives and wound dressings using such pressure-sensitive adhesives have high water absorption, they have issues with water vapor transmission rate, which poses a problem in terms of comfort. Furthermore, in consideration of the decrease in adhesive strength that accompanies the absorption of exudate, many of them have very strong adhesiveness to the skin before absorbing exudate, and when applied to surrounding healthy skin, the adhesive strength becomes excessively strong, and many wound dressings cause severe pain when removed, and in some cases may even remove regenerating skin. The above-mentioned Patent Document 4 proposes that the occurrence of strong pain when peeling off a wound dressing can be avoided by using a specific plasticizer as an essential component. However, from the viewpoints of safety and productivity, there is a demand for a wound dressing that does not cause strong pain when peeled off from a living body even without using a plasticizer, and further improvements are required for hydrocolloid pressure-sensitive adhesive compositions.

[0008] The object of the present invention is to provide a hydrocolloid pressure-sensitive adhesive composition and a hydrocolloid pressure-sensitive adhesive composition which have practical adhesiveness and water absorbency, high water vapor permeability, and can reduce pain when peeled off from a living body. contact The present invention provides an article and a wound dressing comprising a pressure-sensitive adhesive layer made of an adhesive composition. [Means for solving the problem]

[0009] As a result of intensive research into the above-mentioned problems, the present inventors have found that a hydrocolloid pressure-sensitive adhesive composition comprising an acrylic block copolymer and a water-absorbing agent has high water vapor permeability while ensuring practically acceptable adhesiveness and water absorbency, and can reduce pain on the skin when peeled off from a living body, thereby completing the present invention.

[0010] The present invention relates to the following [1] to [7]. [1] A hydrocolloid pressure-sensitive adhesive composition comprising an acrylic block copolymer and a water-absorbing agent (Z). [2] The hydrocolloid pressure-sensitive adhesive composition according to the above [1], wherein the water-absorbing agent (Z) is at least one selected from the group consisting of polysaccharides or derivatives thereof; polyacrylic acid or a salt thereof; polyethylene oxide; polyvinyl alcohol; protein; and poly-N-vinylpyrrolidone. [3] The hydrocolloid type adhesive contact The hydrocolloid pressure-sensitive adhesive composition according to the above [1] or [2], which contains 5 to 50 mass % of the water-absorbing agent (Z) based on the total mass of the pressure-sensitive adhesive composition. [4] The hydrocolloid pressure-sensitive adhesive composition according to any one of the above [1] to [3], wherein the acrylic block copolymer comprises an acrylic triblock copolymer (I) having two polymer blocks (A1) and (A2) composed of methacrylic acid ester units and one polymer block (B) composed of acrylic acid ester units, and having an (A1)-(B)-(A2) block structure. [5] The hydrocolloid pressure-sensitive adhesive composition according to any one of the above [1] to [4], wherein the total content of methacrylic acid ester units in the acrylic block copolymer is 4 to 35 mass %. [6] An article having a substrate and an adhesive layer containing the hydrocolloid adhesive composition according to any one of [1] to [5] above. [7] A wound dressing comprising a substrate and an adhesive layer comprising the hydrocolloid adhesive composition according to any one of [1] to [5] above. [Effects of the Invention]

[0011] According to the present invention, there is provided a hydrocolloid pressure-sensitive adhesive composition and a hydrocolloid pressure-sensitive adhesive composition which have practical adhesiveness and water absorbency, high water vapor permeability, and can reduce pain when detached from a living body. contact An article and a wound dressing can be provided that include an adhesive layer made of the adhesive composition. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a cross-sectional view of a laminate sheet, which is an article including an adhesive layer made of a hydrocolloid-type adhesive composition according to one embodiment of the present invention. [Figure 2] 10A and 10B are plan and cross-sectional views of a wound dressing according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of the present invention will be described. In this specification, "(meth)acrylic acid ester" is a general term for "methacrylic acid ester" and "acrylic acid ester", and "(meth)acrylic" is a general term for "methacrylic" and "acrylic". The present invention also includes any selected or combined embodiment of the matters described in this specification. In this specification, preferred definitions can be selected arbitrarily, and combinations of preferred definitions can be considered more preferred. In this specification, the expression "XX to YY" means "XX or more and YY or less." In this specification, for preferred numerical ranges (e.g., ranges of content, etc.), the lower and upper limits described in stages can be independently combined. For example, the description "preferably 10 to 90, more preferably 30 to 60" can be combined with the "preferable lower limit (10)" and the "more preferable upper limit (60)" to form "10 to 60." In this specification, the term "unit" (where "" indicates a monomer) means "a structural unit derived from", for example, "acrylate unit" means "a structural unit derived from an acrylate ester". As used herein, the term "derived from" with respect to each constitutional unit means that the monomer has undergone the structural changes necessary for polymerization. In this specification, "containing component (X) as a main component" means that component (X) is contained in an amount of 50 mass % or more. In this specification, the term "hydrocolloid pressure-sensitive adhesive composition" refers to a composition having pressure-sensitive adhesive properties in which a water-absorbing agent made of water-absorbing colloidal particles is dispersed in a matrix.

[0014] [Hydrocolloid-type adhesive composition] The hydrocolloid pressure-sensitive adhesive composition according to an embodiment of the present invention contains an acrylic block copolymer and a water-absorbing agent (Z). The hydrocolloid pressure-sensitive adhesive composition has a water-absorbing agent (Z) composed of water-absorbing colloidal particles dispersed in an acrylic block copolymer, and absorbs water and exudates from a wound site. Furthermore, the acrylic block copolymer serves as a matrix, which provides high water vapor transmission rate and facilitates imparting appropriate flexibility, and the pressure-sensitive adhesive properties are unlikely to decrease even after the water-absorbing agent (Z) has absorbed water. Therefore, when the hydrocolloid pressure-sensitive adhesive composition is applied to the vicinity of a wound on a living body, comfort is likely to be maintained. Furthermore, by adjusting the pressure-sensitive adhesive properties of the acrylic block copolymer to an appropriate level in advance, pain can be alleviated when peeling and removing the hydrocolloid pressure-sensitive adhesive composition from the living body after application. Hereinafter, each component constituting the hydrocolloid-type pressure-sensitive adhesive composition will be described.

[0015] [Acrylic block copolymer] The acrylic block copolymer contained in the hydrocolloid pressure-sensitive adhesive composition preferably contains the acrylic triblock copolymer (I) described below, and more preferably contains the acrylic triblock copolymer (I) and the acrylic triblock copolymer (II) described below. When the acrylic triblock copolymer (II) is contained in the pressure-sensitive adhesive composition, tack and processability tend to be further improved, the adhesive composition has better conformability to the body surface, and pain on the skin when the wound dressing is peeled off can be reduced. By using an acrylic block copolymer as a matrix, it becomes easier to uniformly disperse the water-absorbing agent (Z) made of colloidal particles having water absorption properties, compared to when a styrene block copolymer is used as the matrix. In addition, the use of an acrylic block copolymer has the advantage that it is easier to increase flexibility than a styrene block copolymer, thereby ensuring comfort and making it easier to reduce the amount of plasticizer used.

[0016] <Acrylic triblock copolymer (I)> The acrylic block copolymer preferably includes an acrylic triblock copolymer (I) having two polymer blocks (A1) and (A2) composed of methacrylic ester units and one polymer block (B) composed of acrylic ester units, and having an (A1)-(B)-(A2) block structure.

[0017] The acrylic triblock copolymer (I) has an (A1)-(B)-(A2) block structure in which the polymer block (A1), the polymer block (B), and the polymer block (A2) are bonded in this order. When the acrylic triblock copolymer (I) having such a structure is contained in the hydrocolloid pressure-sensitive adhesive composition, the adhesive strength, holding power, and cohesive strength tend to be excellent.

[0018] (Polymer blocks (A1) and (A2)) The acrylic triblock copolymer (I) has two polymer blocks each consisting of a methacrylate ester unit, that is, polymer blocks (A1) and (A2) each consisting of a methacrylate ester unit. In other words, the number of polymer blocks each consisting of a methacrylate ester unit contained in the acrylic triblock copolymer (I) is two.

[0019] Examples of methacrylate esters that serve as structural units of the polymer blocks (A1) and (A2) include methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate, lauryl methacrylate, methacrylate, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate, lauryl methacrylate, methyl ... Examples of methacrylic acid esters include those without functional groups, such as tridecyl acrylate, stearyl methacrylate, isobornyl methacrylate, phenyl methacrylate, and benzyl methacrylate; and methacrylic acid esters with functional groups, such as methoxyethyl methacrylate, ethoxyethyl methacrylate, diethylaminoethyl methacrylate, 2-hydroxyethyl methacrylate, 2-aminoethyl methacrylate, glycidyl methacrylate, and tetrahydrofurfuryl methacrylate.

[0020] Among these, from the viewpoint of improving the heat resistance and durability of the resulting polymer, methacrylic acid esters having no functional group are preferred, and methyl methacrylate, ethyl methacrylate, tert-butyl methacrylate, cyclohexyl methacrylate, isobornyl methacrylate, and phenyl methacrylate are more preferred, and methyl methacrylate is even more preferred because it results in clearer phase separation between the polymer blocks (A1) and (A2) and the polymer block (B) and increases the cohesive force. The polymer blocks (A1) and (A2) may be composed of one kind of these methacrylic acid esters or two or more kinds of them. The acrylic triblock copolymer (I) has two polymer blocks (A1) and (A2) as polymer blocks composed of methacrylic acid ester units, and the methacrylic acid esters constituting the polymer blocks (A1) and (A2) may be the same or different. The proportion of methacrylate units contained in the polymer blocks (A1) and (A2) is preferably 60% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and even more preferably 95% by mass or more, in each of the polymer blocks (A1) and (A2). The proportion of methacrylate units in the polymer blocks (A1) and (A2) may be 100% by mass.

[0021] The stereoregularity of the methacrylate ester units contained in each of the polymer blocks (A1) and (A2) composed of methacrylate ester units may be the same as or different from each other.

[0022] In the acrylic triblock copolymer (I), the total content of the polymer blocks (A1) and (A2) is preferably 35% by mass or less, more preferably 30% by mass or less, and even more preferably 25% by mass or less, and is preferably 4% by mass or more, more preferably 8% by mass or more. In other words, in the acrylic triblock copolymer (I), the total content of the polymer blocks (A1) and (A2) is preferably 4 to 35% by mass. When the total content of the polymer blocks (A1) and (A2) is within the above range, when the acrylic triblock copolymer (I) is used in a hydrocolloid-type pressure-sensitive adhesive composition, there is a tendency that a pressure-sensitive adhesive layer can be prepared which not only has excellent pressure-sensitive adhesive properties but also has excellent conformability to the surface of a living body and can reduce pain on the skin when the wound dressing is peeled off. The contents of the polymer blocks (A1) and (A2) contained in the acrylic triblock copolymer (I) may be the same or different.

[0023] In the acrylic triblock copolymer (I), the weight-average molecular weight of each of the polymer blocks (A1) and (A2) is preferably 3,000 or more, more preferably 4,500 or more, even more preferably 6,000 or more, and is preferably 30,000 or less, more preferably 25,000 or less. When the weight-average molecular weight of each of the polymer blocks (A1) and (A2) is within the above range, when the acrylic triblock copolymer (I) is incorporated into a hydrocolloid-type pressure-sensitive adhesive composition, the composition exhibits excellent cohesive strength while maintaining excellent handleability during production, and the tack and adhesive strength are further improved. In addition, the pressure-sensitive adhesive composition tends to have better heat-resistant adhesion and holding power. The weight average molecular weights of the polymer blocks (A1) and (A2) contained in the acrylic triblock copolymer (I) may be the same or different.

[0024] (Polymer block (B)) The acrylic triblock copolymer (I) has one polymer block (B) composed of acrylate units. In other words, the number of polymer blocks composed of acrylate units contained in the acrylic triblock copolymer (I) is one.

[0025] Examples of acrylic acid esters that serve as structural units of the polymer block (B) include acrylic acid esters that do not have a functional group, such as methyl acrylate, ethyl acrylate, isopropyl acrylate, n-propyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate, amyl acrylate, isoamyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, isooctyl acrylate, decyl acrylate, isobornyl acrylate, lauryl acrylate, octadecyl acrylate, cyclohexyl acrylate, phenyl acrylate, and benzyl acrylate; and acrylic acid esters that have a functional group, such as methoxyethyl acrylate, ethoxyethyl acrylate, 2-hydroxyethyl acrylate, 2-aminoethyl acrylate, glycidyl acrylate, tetrahydrofurfuryl acrylate, diethylaminoethyl acrylate, and phenoxyethyl acrylate.

[0026] Among these, from the viewpoint of transparency and flexibility when prepared as a pressure-sensitive adhesive composition, 1 (In the formula, R 1represents an organic group having 1 to 10 carbon atoms), and from the viewpoint that the phase separation between the polymer blocks (A1) and (A2) and the polymer block (B) is clear and the pressure-sensitive adhesive composition exhibits high cohesive strength, acrylic esters having no functional group, such as methyl acrylate, ethyl acrylate, isopropyl acrylate, n-propyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate, amyl acrylate, isoamyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, isooctyl acrylate, decyl acrylate, isobornyl acrylate, cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, etc., are even more preferred. In terms of the adhesive composition having appropriate adhesiveness at room temperature and exhibiting stable adhesive strength over a wide temperature range and under wide peel speed conditions, at least one selected from methyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate and isooctyl acrylate is even more preferred, and n-butyl acrylate and 2-ethylhexyl acrylate are particularly preferred.

[0027] The polymer block (B) may be composed of one or more of these acrylic esters. The proportion of acrylic ester units contained in the polymer block (B) is preferably 60% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and even more preferably 95% by mass or more. The proportion of acrylic ester units in the polymer block (B) may be 100% by mass.

[0028] In the acrylic triblock copolymer (I), the content of the polymer block (B) is 65% by mass or more, preferably 70% by mass or more, more preferably 75% by mass or more, and even more preferably 77% by mass or more. Furthermore, the content of the polymer block (B) is preferably 96% by mass or less, more preferably 92% by mass or less. When the content of the polymer block (B) is within the above range, when the acrylic triblock copolymer (I) is used in a hydrocolloid-type pressure-sensitive adhesive composition, a pressure-sensitive adhesive layer can be obtained that not only has excellent pressure-sensitive adhesive performance but also has excellent conformability to the body surface and can reduce pain on the skin when the wound dressing is peeled off.

[0029] Polymer blocks (A1) and (A2) and polymer block (B) may contain the monomer components of each other to the extent that the effects of the present invention are not impaired. For example, a tapered structure may be formed at the boundary between polymer block (A1) or (A2) and polymer block (B). Furthermore, polymer block (A1) or (A2) and polymer block (B) may not contain the monomer components of each other.

[0030] Furthermore, polymer blocks (A1) and (A2) and polymer block (B) may contain other monomer units as necessary. Examples of such other monomers include vinyl monomers having a carboxyl group, such as (meth)acrylic acid, crotonic acid, maleic acid, maleic anhydride, and fumaric acid; vinyl monomers having a functional group, such as (meth)acrylamide, (meth)acrylonitrile, vinyl acetate, vinyl chloride, and vinylidene chloride; aromatic vinyl monomers, such as styrene, α-methylstyrene, p-methylstyrene, and m-methylstyrene; conjugated diene monomers, such as butadiene and isoprene; olefin monomers, such as ethylene, propylene, isobutene, and octene; and lactone monomers, such as ε-caprolactone and valerolactone. When each polymer block contains such other monomers, the content thereof is preferably 20% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less, based on the total mass of the monomers constituting each polymer block.

[0031] The weight average molecular weight (Mw) of the acrylic triblock copolymer (I) is preferably 50,000 to 250,000. From the viewpoints of adhesive performance and ease of handling during production, it is more preferably 60,000 to 240,000. When the Mw of the acrylic triblock copolymer (I) is 50,000 or more, adhesive performance is easily improved. Furthermore, when the Mw is 250,000 or less, handling during production is easily improved.

[0032] The molecular weight distribution (Mw / Mn) of the acrylic triblock copolymer (I) is preferably 1.0 to 1.5, and more preferably 1.0 to 1.4, from the viewpoints of reducing the amount of components migrating to the body surface and reducing pain on the skin when the wound dressing is peeled off. Note that the weight-average molecular weight (Mw) and number-average molecular weight (Mn) in this specification are weight-average molecular weight and number-average molecular weight in terms of standard polystyrene determined by gel permeation chromatography (GPC) measurement.

[0033] A particularly preferred embodiment of the acrylic triblock copolymer (I) is a triblock copolymer having an (A1)-(B)-(A2) block structure, which comprises two polymer blocks (A1) and (A2) each consisting of a methacrylic acid ester unit and one polymer block (B) each consisting of an acrylic acid ester unit, and which has a weight-average molecular weight of 50,000 to 250,000, in which the total content of the polymer blocks (A1) and (A2) is 35 mass% or less, and in which the weight-average molecular weight of each of the polymer blocks (A1) and (A2) is 3,000 or more.

[0034] <Acrylic triblock copolymer (II)> The acrylic triblock copolymer (II) that can be contained as an optional component in the hydrocolloid pressure-sensitive adhesive composition has at least two polymer blocks (C1) and (C2) composed of methacrylic acid ester units and at least one polymer block (D) composed of acrylic acid ester units, and has a (C1)-(D)-(C2) block structure, and the weight average molecular weight of at least one of the two polymer blocks (C1) and (C2) is smaller than the weight average molecular weight of the polymer blocks (A1) and (A2) contained in the acrylic triblock copolymer (I). Preferably, the weight average molecular weights of the two polymer blocks (C1) and (C2) are both smaller than the weight average molecular weight of the polymer blocks (A1) and (A2) contained in the acrylic triblock copolymer (I).

[0035] (Polymer blocks (C1) and (C2)) The acrylic triblock copolymer (II) has two polymer blocks (C1) and (C2) each consisting of a methacrylate ester unit.

[0036] Specific examples of the methacrylic acid esters that serve as structural units of the polymer blocks (C1) and (C2) are the same as the methacrylic acid esters that serve as structural units of the polymer blocks (A1) and (A2) of the acrylic triblock copolymer (I).

[0037] Among these, methacrylic acid esters without functional groups are preferred from the viewpoint of improving the heat resistance and durability of the resulting polymer. Methyl methacrylate, ethyl methacrylate, tert-butyl methacrylate, cyclohexyl methacrylate, isobornyl methacrylate, and phenyl methacrylate are more preferred. Methyl methacrylate is even more preferred because it results in clearer phase separation between polymer blocks (C1) and (C2) and polymer block (D) and higher cohesive strength. Polymer blocks (C1) and (C2) may be composed of one or more of these methacrylic acid esters. The proportion of methacrylic acid ester units in polymer blocks (C1) and (C2) is preferably 60% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and even more preferably 95% by mass or more. The proportion of methacrylic acid ester units in polymer blocks (C1) and (C2) may be 100% by mass.

[0038] In the acrylic triblock copolymer (II), the total content of the polymer blocks (C1) and (C2) is preferably 25% by mass or less, more preferably 20% by mass or less, and even more preferably 10% by mass or less, and is preferably 5% by mass or more, and more preferably 6% by mass or more. In other words, in the acrylic triblock copolymer (II), the total content of the polymer blocks (C1) and (C2) is preferably 25% by mass or less, more preferably 20% by mass or less, and even more preferably 10% by mass or less. C 1) and ( C The total content of 2) is preferably 5 to 25% by mass. When the total content of the polymer blocks (C1) and (C2) is within the above range, when the acrylic triblock copolymer (II) is contained in a pressure-sensitive adhesive composition, the tackiness and processability tend to be further improved without impairing the cohesive force.

[0039] The acrylic triblock copolymer (II) preferably has polymer blocks (C1) and (C2) with different weight-average molecular weights. In this case, the weight-average molecular weight of at least one of the polymer blocks (C1) and (C2) is 300 or more and less than 3,000. Preferably, it is 500 or more and less than 3,000. When the weight-average molecular weight of at least one of the polymer blocks (C1) and (C2) is 300 or more, the resulting acrylic triblock copolymer (II) tends to have excellent cohesive strength. When the weight-average molecular weight of at least one of the polymer blocks (C1) and (C2) is less than 3,000, the melt viscosity of the resulting acrylic triblock copolymer (II) tends to be low, which tends to improve productivity in producing the pressure-sensitive adhesive composition.

[0040] In the (C1)-(D)-(C2) block structure, the weight-average molecular weight of the polymer block (C2) is preferably 300 or more but less than 3,000, and more preferably 500 or more but less than 2,000. The weight-average molecular weight of the polymer block (C1) is preferably 3,000 or more but less than 10,000, and more preferably 3,000 or more but less than 7,000. When the weight-average molecular weight is within the above range, the viscosity, cohesive strength, and ease of handling during production are excellent.

[0041] The stereoregularities of the methacrylate ester units contained in the polymer blocks (C1) and (C2) may be the same or different.

[0042] (Polymer block (D)) The acrylic triblock copolymer (II) has at least one polymer block (D) consisting of an acrylic ester unit.

[0043] Specific examples of the acrylic acid ester that serves as a structural unit of the polymer block (D) are the same as the acrylic acid ester that serves as a structural unit of the polymer block (B) of the acrylic triblock copolymer (I).

[0044] Among these, from the viewpoint of transparency and flexibility when prepared as a pressure-sensitive adhesive composition, 1 (In the formula, R 1 represents an organic group having 1 to 10 carbon atoms), and from the viewpoint that the phase separation between the polymer blocks (C1) and (C2) and the polymer block (D) is clear and the pressure-sensitive adhesive composition exhibits high cohesive strength, acrylic esters having no functional group, such as methyl acrylate, ethyl acrylate, isopropyl acrylate, n-propyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate, amyl acrylate, isoamyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, isooctyl acrylate, decyl acrylate, isobornyl acrylate, cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, etc., are even more preferred. In terms of the adhesive composition having appropriate adhesiveness at room temperature and exhibiting stable adhesive strength over a wide temperature range and under wide peel speed conditions, at least one selected from methyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate and isooctyl acrylate is even more preferred, and n-butyl acrylate is particularly preferred.

[0045] The polymer block (D) may be composed of one or more of these acrylic esters. The proportion of acrylic ester units contained in the polymer block (D) is preferably 60% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and even more preferably 95% by mass or more. The proportion of acrylic ester units in the polymer block (D) may be 100% by mass.

[0046] In the acrylic triblock copolymer (II), the content of the polymer block (D) is usually 75% by mass or more, preferably 80% by mass or more, and more preferably 90% by mass or more. The content of the polymer block (D) is usually 95% by mass or less, and preferably 94% by mass or less. When the content of the polymer block (D) is within the above range, when the acrylic triblock copolymer (II) is contained in an adhesive composition, it is possible to obtain an adhesive layer that has improved tack and processability without impairing holding power, has excellent conformability to the body surface, and can reduce pain on the skin when the wound dressing is peeled off.

[0047] Polymer blocks (C1) and (C2) and polymer block (D) may contain the monomer components of each other to the extent that the effects of the present invention are not impaired. For example, the boundary between polymer block (C1) or (C2) and polymer block (D) may have a tapered structure. Furthermore, polymer block (C1) or (C2) and polymer block (D) may not contain the monomer components of each other.

[0048] Furthermore, the polymer blocks (C1) and (C2) and polymer block (D) may contain other monomer units as needed. Specific examples of such other monomers are the same as the other monomers exemplified as the other monomers used for the other monomer units optionally contained in the polymer blocks (A1) and (A2) and polymer block (B) of the acrylic triblock copolymer (I). When each polymer block contains such other monomers, the content thereof is preferably 20% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less, based on the total mass of the monomers constituting each polymer block.

[0049] The acrylic triblock copolymer (II) has a (C1)-(D)-(C2) block structure in which the polymer block (C1), the polymer block (D), and the polymer block (C2) are bonded in this order. When the acrylic triblock copolymer (II) having such a structure is contained in the pressure-sensitive adhesive composition, the tack and processability tend to be further improved, the adhesive composition has better conformability to the biological surface, and the pain on the skin when the wound dressing is peeled off can be reduced.

[0050] The weight-average molecular weight of the acrylic triblock copolymer (II) is 10,000 to 120,000. From the viewpoints of cohesive strength and ease of handling during production, it is preferably 20,000 to 110,000, more preferably 25,000 to 100,000, and even more preferably 30,000 to 90,000. When the acrylic triblock copolymer (II) has a weight-average molecular weight of less than 10,000, the cohesive strength may be poor when the copolymer is contained in a pressure-sensitive adhesive composition. On the other hand, when the weight-average molecular weight exceeds 120,000, the handleability during production and the ability to conform to the body surface tend to be impaired, and the skin tends to be more painful when the wound dressing is peeled off.

[0051] The molecular weight distribution of the acrylic triblock copolymer (II) is preferably 1.0 to 1.5, and more preferably 1.0 to 1.4, from the viewpoints of easily reducing the amount of components migrating to the body surface and easily reducing pain on the skin when the wound dressing is peeled off.

[0052] The acrylic triblock copolymer (II) preferably has a melt viscosity of 100,000 mPa·s or less at 100°C measured with a Brookfield viscometer. The melt viscosity is preferably 1,000 mPa·s or more and 100,000 mPa·s or less, and more preferably 5,000 mPa·s or more and 100,000 mPa·s or less. By having such a melt viscosity, the acrylic triblock copolymer (II) is not in a solid state at room temperature (about 25°C) but has low fluidity, and tends to have excellent workability when added to a pressure-sensitive adhesive composition.

[0053] A particularly preferred embodiment of the acrylic triblock copolymer (II) is an acrylic triblock copolymer having at least two polymer blocks (C1) and (C2) composed of methacrylic acid ester units and at least one polymer block (D) composed of acrylic acid ester units, and having a (C1)-(D)-(C2) block structure, in which the total content of the polymer blocks (C1) and (C2) is 25 mass% or less, and at least one of the polymer blocks (C1) and (C2) has a weight average molecular weight of 300 or more and less than 3,000.

[0054] When the hydrocolloid pressure-sensitive adhesive composition contains an acrylic triblock copolymer (II), the mass ratio of the acrylic triblock copolymer (I) to the acrylic triblock copolymer (II) is not particularly limited, but in order to achieve a good balance between adhesive strength, cohesive strength, and pressure-sensitive adhesive properties, the mass ratio of the acrylic triblock copolymer (I) to the acrylic triblock copolymer (II) is preferably 100:1 to 100:500, more preferably 100:2 to 100:400, even more preferably 100:3 to 100:300, still more preferably 100:4 to 100:200, still more preferably 100:5 to 100:100, still more preferably 100:6 to 100:90, and particularly preferably 100:7 to 100:80.

[0055] From the viewpoint of durability and the like, the total content of methacrylic acid ester units in the acrylic block copolymer is preferably 4 to 35 mass %, more preferably 4.5 to 30 mass %, even more preferably 5 to 25 mass %, and still more preferably 5 to 20 mass %, relative to the total mass of the acrylic block copolymer.

[0056] <Method of producing acrylic triblock copolymer> The method for producing the acrylic triblock copolymer is not particularly limited, and any method based on a known technique can be used. Generally, to obtain a block copolymer with a narrow molecular weight distribution, a living polymerization method of the monomers that are the constituent units is adopted. Such living polymerization techniques include, for example, a living polymerization method using an organic rare earth metal complex as a polymerization initiator (see JP-A-06-93060), a living anionic polymerization method using an organic alkali metal compound as a polymerization initiator in the presence of a mineral acid salt such as an alkali metal or alkaline earth metal salt (see JP-A-05-507737), a living anionic polymerization method using an organic alkali metal compound as a polymerization initiator in the presence of an organoaluminum compound (see JP-A-11-335432), and atom transfer radical polymerization (ATRP) (see Macromolecular Chemistry and Physics, 2000, Vol. 201, pp. 1108-1114). The molecular weight distribution of copolymers obtained by living anionic polymerization tends to have a sharper peak than the molecular weight distribution of polymers obtained by free radical polymerization, and since it is easier to complete the polymerization of all monomers, unreacted monomer raw materials are less likely to remain in block copolymers of acrylic monomers.

[0057] Among the above production methods, the method of living anionic polymerization using an organic alkali metal compound as a polymerization initiator in the presence of an organoaluminum compound is preferred because the resulting block copolymer has high transparency, contains less residual monomer, has a reduced odor, and, when used as an adhesive composition, inhibits the generation of bubbles after lamination. Furthermore, this method is preferred from the viewpoints of easily reducing the amount of components migrating to the body surface and easily reducing skin pain when the wound dressing is peeled off. Furthermore, this method is preferred because the molecular structure of the methacrylic acid ester polymer block is highly syndiotactic, which has the effect of enhancing the heat resistance of the adhesive composition, and because living polymerization can be performed under relatively mild temperature conditions, resulting in a small environmental impact (mainly the power required for a refrigerator to control the polymerization temperature) when produced industrially.

[0058] The organoaluminum compound may be, for example, an organoaluminum compound represented by the following general formula (1). AlR2 R 3 R 4 (1) (In formula (1), R 2 , R 3 and R 4 each independently represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryloxy group, or an N,N-disubstituted amino group, or R 2 is any of the groups described above, and R 3 and R 4 together form a substituted or unsubstituted arylenedioxy group.

[0059] Preferred examples of the organoaluminum compound represented by the general formula (1) include isobutylbis(2,6-di-tert-butyl-4-methylphenoxy)aluminum, isobutylbis(2,6-di-tert-butylphenoxy)aluminum, and isobutyl[2,2'-methylenebis(4-methyl-6-tert-butylphenoxy)]aluminum, from the viewpoints of high living polymerization properties and ease of handling.

[0060] Examples of the organic alkali metal compound include alkyllithiums and alkyldilithiums such as n-butyllithium, sec-butyllithium, isobutyllithium, tert-butyllithium, n-pentyllithium, and tetramethylenedilithium; aryllithiums and aryldilithiums such as phenyllithium, p-tolyllithium, and lithium naphthalene; aralkyllithiums and aralkyldilithiums such as benzyllithium, diphenylmethyllithium, and dilithium produced by the reaction of diisopropenylbenzene with butyllithium; lithium amides such as lithium dimethylamide; and lithium alkoxides such as methoxylithium and ethoxylithium. These may be used alone or in combination of two or more. Among these, alkyllithiums are preferred due to their high polymerization initiation efficiency, with tert-butyllithium and sec-butyllithium being more preferred, and sec-butyllithium being even more preferred.

[0061] The living anionic polymerization is usually carried out in the presence of a solvent inert to the polymerization reaction, such as aromatic hydrocarbons (e.g., toluene, xylene, etc.), halogenated hydrocarbons (e.g., chloroform, methylene chloride, carbon tetrachloride, etc.), and ethers (e.g., tetrahydrofuran, diethyl ether, etc.), with toluene being preferred.

[0062] Block copolymers can be produced, for example, by repeating the process of forming desired polymer blocks (polymer block (A1), polymer block (B), etc.) at the desired living polymer ends obtained by polymerizing monomers a desired number of times and then terminating the polymerization reaction. Specifically, for example, a multi-stage polymerization process including a first step in which a monomer forming a first polymer block is polymerized using a polymerization initiator composed of an organic alkali metal compound in the presence of an organoaluminum compound, a second step in which a monomer forming a second polymer block is polymerized, and a third step in which a monomer forming a third polymer block is polymerized, can be carried out. The active end of the resulting polymer is then reacted with an alcohol or the like to terminate the polymerization reaction, thereby producing acrylic triblock copolymers (I) and (II). According to the above-described method, triblock copolymers consisting of polymer block (A1), polymer block (B), and polymer block (A2), and triblock copolymers consisting of polymer block (C1), polymer block (D), and polymer block (C2), can be produced.

[0063] The polymerization temperature is preferably 0 to 100°C when forming polymer blocks (A1), (A2), (C1), and (C2), and -50 to 50°C when forming polymer blocks (B) and (D). If the polymerization temperature is lower than the above range, the reaction proceeds slowly, and a long time is required to complete the reaction. On the other hand, if the polymerization temperature is higher than the above range, deactivation of living polymer ends increases, resulting in a broad molecular weight distribution or failure to obtain the desired block copolymer. Furthermore, each polymer block can be polymerized within a range of 1 second to 20 hours.

[0064] In addition, when the acrylic block copolymer contains the acrylic triblock copolymers (I) and (II), the acrylic block copolymer can be produced by preparing the acrylic triblock copolymers (I) and (II) by any of the methods described above and melt-kneading them.

[0065] [Water absorbent (Z)] Examples of the water-absorbing agent (Z) contained in the hydrocolloid pressure-sensitive adhesive composition include at least one selected from the group consisting of polysaccharides or derivatives thereof, such as corn starch, guar gum, locust bean gum, starch, pectin, alginic acid and its salts, carrageenan, agar, chitin, chitosan, karaya gum, gum arabic, xanthan gum, dextrin, dextran, carboxymethyl cellulose, carboxymethyl cellulose sodium, carboxymethyl cellulose calcium, hydroxyalkyl methyl cellulose, hydroxypropyl cellulose, methyl cellulose, starch acetate, starch phosphate, hydroxyethylated starch, hydroxypropyl starch, oxidized starch, dextrinized starch, and starch-acrylic acid graft polymers; polyacrylic acid or its salts; polyethylene oxide; polyvinyl alcohol; proteins, such as collagen and gelatin; and poly-N-vinylpyrrolidone. Among these, it is preferable to use sodium carboxymethyl cellulose, which has particularly good heat resistance, as the water absorbent (Z). Commercially available products of the above-mentioned sodium carboxymethylcellulose include Cellogen (registered trademark) F-3H (Dai-ichi Kogyo Seiyaku Co., Ltd.), and commercially available products of carboxymethylcellulose include MAC200HC and Sunrose (registered trademark) F10LC (both Nippon Paper Chemicals Co., Ltd.).

[0066] The water-absorbing agent (Z) is preferably uniformly dispersed in the hydrocolloid pressure-sensitive adhesive composition. Uniform dispersion reduces the likelihood of variations in adhesive performance and water absorption performance, and therefore evaluation of the performance variations can be used as an index of whether the water-absorbing agent is uniformly dispersed. If the water-absorbing agent is not uniformly dispersed, variations are likely to occur in terms of adhesive performance and water absorption performance.

[0067] The content of the water absorbent (Z) is determined from the viewpoint of obtaining an appropriate water absorption speed and amount. contactThe content of the water-absorbing agent (Z) is preferably 5 to 50% by mass, more preferably 10 to 50% by mass, and even more preferably 15 to 50% by mass, based on the total mass of the adhesive composition. When the content of the water-absorbing agent (Z) is within the above range, liquid absorbency, particularly water absorbency, adhesion to the wound site, and appropriate shape retention (ability to prevent the plaster body from spilling out from the sides) are easily obtained.

[0068] <Other optional ingredients> Other optional components that may be contained in the hydrocolloid pressure-sensitive adhesive composition include a tackifying resin and a plasticizer.

[0069] (tackifying resin) The hydrocolloid-type pressure-sensitive adhesive composition may contain a tackifier resin. When the pressure-sensitive adhesive composition contains a tackifier resin, at least one of adhesiveness, tackiness, and compatibility is likely to be improved.

[0070] The tackifying resin that can be contained in the hydrocolloid pressure-sensitive adhesive composition can be any of the tackifying resins that have been conventionally used in pressure-sensitive adhesives. Specific examples of the tackifying resin include rosin-based resins (rosin, rosin derivatives, hydrogenated rosin derivatives, etc.), terpene-based resins, (hydrogenated) petroleum-based resins, aromatic hydrocarbon-based resins such as styrene-based resins, xylene-based resins, hydrogenated aromatic copolymers, and phenol-based resins, and coumarone-indene-based resins.

[0071] In this specification, rosin resin refers to an amber-colored, amorphous natural resin obtained from pine trees, whose main component is a mixture of abietic acid and its isomers. Rosin resins also include those that have been modified by esterification, polymerization, hydrogenation (hereinafter also referred to as hydrogenation), or other methods that utilize the reactivity of abietic acid or its isomers. Examples of rosin-based resins include unmodified rosins (e.g., tall rosin, gum rosin, and wood rosin), polymerized rosin, disproportionated rosin, hydrogenated rosin, maleic acid-modified rosin, fumaric acid-modified rosin, and esters thereof (e.g., glycerin ester, pentaerythritol ester, methyl ester, ethyl ester, butyl ester, and ethylene glycol ester), as well as those further modified by hydrogenation, etc. Among these, hydrogenated rosin esters are preferred from the viewpoints of heat resistance and coloration resistance.

[0072] In this specification, the term "terpene resin" refers to an oligomer obtained by polymerizing a raw material containing a terpene monomer. The term also refers to an oligomer obtained by modifying the oligomer obtained in this manner, such as by hydrogenation. Terpene generally refers to a polymer of isoprene (C5H8), and monoterpene (C 10 H 16 ), sesquiterpenes (C 15 H 24 ), diterpenes (C 20 H 32 Terpene monomers are monomers having these as basic skeletons, and examples thereof include α-pinene, β-pinene, dipentene, limonene, myrcene, alloocimene, ocimene, α-phellandrein, α-terpinene, γ-terpinene, terpinolene, 1,8-cineole, 1,4-cineole, α-terpineol, β-terpineol, γ-terpineol, sabinene, paramentadienes, and carenes. Furthermore, the raw material containing a terpene monomer may also contain other monomers copolymerizable with the terpene monomer, for example, coumarone monomers such as benzofuran (CHO); vinyl aromatic compounds such as styrene, α-methylstyrene, vinyltoluene, divinyltoluene, and 2-phenyl-2-butene; and phenolic monomers such as phenol, cresol, xylenol, propylphenol, norylphenol, hydroquinone, resorcinol, methoxyphenol, bromophenol, bisphenol A, and bisphenol F. Examples of oligomers obtained by polymerizing a raw material containing another monomer copolymerizable with the terpene monomer include terpene phenol resins. Such terpene phenol resins are also included in the terpene resins. In addition, oligomers obtained by polymerizing a raw material containing a terpene monomer and another monomer copolymerizable with the terpene monomer, and then modifying the oligomer by hydrogenation or the like, are also included in the terpene resins.

[0073] As used herein, (hydrogenated) petroleum-based resin refers to oligomers obtained by polymerizing raw materials consisting of a C5 fraction, a C9 fraction, a refined component of a C5 fraction, a refined component of a C9 fraction, or a mixture of these fractions or refined components. Oligomers obtained in this manner that have been modified by hydrogenation or other methods are also included in the above-mentioned (hydrogenated) petroleum-based resins. The C5 fraction typically includes cyclopentadiene, dicyclopentadiene, isoprene, 1,3-pentadiene, 2-methyl-1-butene, 2-methyl-2-butene, 1-pentene, 2-pentene, and cyclopentene, while the C9 fraction typically includes styrene, allylbenzene, α-methylstyrene, vinyltoluene, β-methylstyrene, and indene. The C9 fraction may also contain small amounts of C8 and C10 fractions.

[0074] The (hydrogenated) petroleum-based resins are broadly classified into C5 resins made from C5 fractions or their refined components, C9 resins made from C9 fractions or their refined components, and C5-C9 copolymer resins made from a mixture of C5 fractions or their refined components and C9 fractions or their refined components. Among these, hydrogenated petroleum-based resins are particularly preferred from the viewpoints of heat resistance and coloration resistance.

[0075] Examples of the aromatic hydrocarbon resin include oligomers obtained by polymerizing raw materials consisting of styrene, α-methylstyrene, vinyltoluene, β-methylstyrene, divinyltoluene, 2-phenyl-2-butene, methoxystyrene, t-butylstyrene, chlorostyrene, indene, methylindene, phenol, cresol, xylenol, propylphenol, nonylphenol, hydroquinone, resorcinol, methoxyphenol, bromophenol, bisphenol A, bisphenol F, or mixtures thereof, and modified oligomers such as those hydrogenated. Among these, styrene resins are preferably used from the viewpoints of compatibility, heat resistance, and coloration resistance.

[0076] These tackifier resins may be contained alone or in combination of two or more. The use of two or more tackifier resins is desirable in that it provides an excellent balance between adhesive strength and tack. Furthermore, the softening point of the tackifier resin is preferably 50 to 160°C in order to achieve high adhesive strength. The softening point can be measured by the ring and ball method specified in JIS K2207 (1996).

[0077] The content of the tackifier resin may be appropriately set depending on the application, etc., but from the viewpoint of obtaining a pressure-sensitive adhesive layer that has high conformability to and retention power over the biological surface while simultaneously achieving higher adhesive strength, tackiness, and cohesive strength, the content is preferably 1 to 180 parts by mass, more preferably 2 to 100 parts by mass, even more preferably 4 to 80 parts by mass, still more preferably 5 to 60 parts by mass, even more preferably 6 to 50 parts by mass, still more preferably 7 to 40 parts by mass, still more preferably 8 to 30 parts by mass, and particularly preferably 9 to 25 parts by mass, relative to 100 parts by mass of the acrylic triblock copolymer.

[0078] When the tackifier resin is a (hydrogenated) petroleum-based resin or a terpene-based resin composed only of a terpene-based monomer, it tends to be difficult to increase the content from the viewpoint of compatibility with the acrylic triblock copolymer. Therefore, when these are used as the tackifier resin, from the viewpoints of adhesive strength, tackiness, cohesive strength, and compatibility, the content of the tackifier resin is preferably 2 to 40 parts by mass, more preferably 2 to 30 parts by mass, per 100 parts by mass of the acrylic triblock copolymer (I).

[0079] (plasticizer) The hydrocolloid pressure-sensitive adhesive composition may or may not contain a plasticizer. When the hydrocolloid pressure-sensitive adhesive composition contains a plasticizer, it becomes easier to obtain a pressure-sensitive adhesive composition that has an excellent balance between adhesive strength and tack. When the hydrocolloid pressure-sensitive adhesive composition does not contain a plasticizer, it becomes easier to suppress a decrease in adhesive performance due to bleeding out of the plasticizer from the hydrocolloid pressure-sensitive adhesive composition.

[0080] Examples of such plasticizers include phthalates such as dibutyl phthalate, di-n-octyl phthalate, bis(2-ethylhexyl) phthalate, bis(2-ethylhexyl) terephthalate, di-n-decyl phthalate, and diisodecyl phthalate; adipates such as bis(2-ethylhexyl) adipate, diisodecyl adipate, and di-n-octyl adipate; sebacates such as bis(2-ethylhexyl) sebacate and di-n-butyl sebacate; azelaates such as bis(2-ethylhexyl) azelate; citrates such as acetyl tributyl citrate; paraffins such as chlorinated paraffin; polypropylene glycol, etc. glycols; epoxy-modified vegetable oils such as epoxidized soybean oil and epoxidized linseed oil; phosphate esters such as trioctyl phosphate and triphenyl phosphate; phosphites such as triphenyl phosphite; ester oligomers such as esters of adipic acid and 1,3-butylene glycol, and esters of benzoic acid and dipropylene glycol; sugar derivatives such as sucrose acetate isobutyrate; low molecular weight polymers such as low molecular weight polybutene, low molecular weight polyisobutylene, and low molecular weight polyisoprene; acrylic oligomers such as poly(n-butyl acrylate) and poly(2-ethylhexyl acrylate); Diana Process Oil PW series (manufactured by Idemitsu Kosan Co., Ltd.), SUNPURE Examples of suitable plasticizers include paraffinic oils such as LW70 and P series (manufactured by Nippon Sun Oil Co., Ltd.), naphthenic oils such as SUNPURE N90 and NX90 and SUNTHENE series (manufactured by Nippon Sun Oil Co., Ltd.), and aromatic oils such as JSO AROMA 790 (manufactured by Nippon Sun Oil Co., Ltd.) and Vivatec 500 (manufactured by H&R). These plasticizers may be contained alone or in combination.

[0081] The content of the plasticizer may be appropriately set depending on the application, etc., but is preferably 1 to 40 parts by mass, more preferably 1 to 25 parts by mass, relative to 100 parts by mass of the acrylic triblock copolymer (I), from the viewpoints of obtaining a pressure-sensitive adhesive composition that is free from bleeding and has excellent transparency, and obtaining a pressure-sensitive adhesive layer that has high conformability and holding power to the body surface and is capable of reducing pain on the skin when the wound dressing is peeled off.

[0082] (Other polymers and additives) The hydrocolloid pressure-sensitive adhesive composition may contain additives such as other polymers, softeners, heat stabilizers, light stabilizers, antistatic agents, flame retardants, foaming agents, colorants, dyes, refractive index modifiers, fillers, curing agents, anti-sticking agents, etc. These other polymers and additives may be contained alone or in combination of two or more.

[0083] Examples of the other polymers include acrylic resins such as polymethyl methacrylate and (meth)acrylic acid ester copolymers (excluding acrylic triblock copolymers (I) and (II)); olefin resins such as polyethylene, ethylene-vinyl acetate copolymer, polypropylene, polybutene-1, poly-4-methylpentene-1, and polynorbornene; ethylene ionomers; styrene resins such as polystyrene, styrene-maleic anhydride copolymer, high-impact polystyrene, AS resin, ABS resin, AES resin, AAS resin, ACS resin, and MBS resin; and styrene-methyl methacrylate copolymers. Examples of suitable adhesives include polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polylactic acid; polyamides such as nylon 6, nylon 66, and polyamide elastomers; polycarbonate; polyvinyl chloride; polyvinylidene chloride; polyvinyl alcohol; ethylene-vinyl alcohol copolymers; polyacetal; polyvinylidene fluoride; polyurethane; modified polyphenylene ether; polyphenylene sulfide; silicone rubber-modified resins; acrylic rubbers; silicone rubbers; styrene-based thermoplastic elastomers such as SEPS, SEBS, and SIS; and olefin-based rubbers such as IR, EPR, and EPDM. Among these, from the viewpoint of compatibility with the acrylic triblock copolymer (I) contained in the pressure-sensitive adhesive composition, acrylic resins (excluding the acrylic triblock copolymers (I) and (II)), ethylene-vinyl acetate copolymers, AS resins, polylactic acid, polyvinylidene fluoride, and styrene-based thermoplastic elastomers are preferred, and (meth)acrylic acid ester copolymers (excluding the acrylic triblock copolymers (I) and (II)) are more preferred.

[0084] Examples of the filler include inorganic fibers such as glass fibers and carbon fibers, organic fibers, inorganic fillers such as calcium carbonate, talc, titanium oxide, silica, clay, barium sulfate and magnesium carbonate, carbon black, etc. When these fillers are contained, the resulting pressure-sensitive adhesive composition is endowed with durability, heat resistance and weather resistance.

[0085] When the hydrocolloid pressure-sensitive adhesive composition contains an anti-sticking agent, it is possible to expect improvement in handleability. Examples of the anti-sticking agent include fatty acids such as stearic acid and palmitic acid; fatty acid metal salts such as calcium stearate, zinc stearate, magnesium stearate, potassium palmitate and sodium palmitate; waxes such as polyethylene wax, polypropylene wax and montanic acid wax; low molecular weight polyolefins such as low molecular weight polyethylene and low molecular weight polypropylene; acrylic resin powder; polyorganosiloxanes such as dimethylpolysiloxane; octadecylamine, alkyl phosphate, fatty acid ester, amide resin powders such as ethylene bisstearylamide, fluororesin powders such as tetrafluoroethylene resin, molybdenum disulfide powder, silicone resin powder, silicone rubber powder, silica, etc.

[0086] [Method for producing hydrocolloid-type pressure-sensitive adhesive composition] The method for producing the hydrocolloid pressure-sensitive adhesive composition is not particularly limited, but from the viewpoint of uniformly mixing the water-absorbing agent, tackifying resin, etc., it is preferable to mix the components, for example, using a known mixing or kneading device such as a kneader-ruder, extruder, mixing roll, or Banbury mixer, usually at a temperature in the range of 100 to 250°C. The obtained pressure-sensitive adhesive composition can be used after heating and melting. From the viewpoint of processability and handling, a low melt viscosity is preferable. On the other hand, from the viewpoint of achieving both adhesive properties and high holding power (creep resistance) of the pressure-sensitive adhesive composition, a high melt viscosity is preferable.

[0087] [Hydrocolloid type contact Articles containing a pressure-sensitive adhesive layer made of an adhesive composition

[0043] The hydrocolloid pressure-sensitive adhesive composition can be used in the form of an article having a pressure-sensitive adhesive layer comprising the hydrocolloid pressure-sensitive adhesive composition, and is suitably used in the form of, for example, a laminate such as a laminate film or laminate sheet, which is an article comprising a substrate and a pressure-sensitive adhesive layer comprising the hydrocolloid pressure-sensitive adhesive composition.

[0088] The above hydrocolloid type adhesive contact The adhesive composition is applied in an appropriate amount to a substrate to form a pressure-sensitive adhesive layer, thereby obtaining the article. contact The adhesive composition can also be used as a pad for a first aid bandage by directly applying or pasting the adhesive composition onto a support, or by interposing a film or the like between the support and the adhesive layer.

[0089] FIG. 1 shows a hydrocolloid type viscosity control agent according to one embodiment of the present invention. contact 1 is a cross-sectional view of a laminated sheet, which is an article including a pressure-sensitive adhesive layer made of an adhesive composition. As shown in Fig. 1, the laminated sheet 100 includes a substrate 10, a hydrocolloid pressure-sensitive adhesive layer 20, and a release sheet 30, which are laminated in this order. The hydrocolloid pressure-sensitive adhesive layer 20 is a pressure-sensitive adhesive layer made of the hydrocolloid pressure-sensitive adhesive composition. Since the hydrocolloid adhesive layer 20 has water absorption and adhesive properties, the laminated sheet 100 can be applied to the target area, such as a wound, either as is or by cutting it to an appropriate size and shape and removing the release sheet 30.

[0090] When the hydrocolloid-type adhesive composition is heated and melted to form the adhesive layer, it can be formed into a sheet or film shape using, for example, a hot melt coating method, a T-die method, an inflation method, a calendar molding method, a lamination method, or the like. For example, a 100 to 1,000 μm thick adhesive layer can be formed on a release sheet by melt coating the heated and melted adhesive composition using, for example, a hot melt coater. The thickness of the adhesive layer is not particularly limited, but when a constant thickness is desired to ensure adhesion to the skin and to strike a balance with the thickness of the substrate, it is preferably 100 to 1,000 μm, more preferably 150 to 900 μm, and even more preferably 200 to 800 μm. The article can be produced by laminating a substrate thereon. When the hydrocolloid pressure-sensitive adhesive composition has a high melt viscosity, for example, when the melt viscosity at 180°C exceeds 20,000 mPa s, the composition is heated and melted at a higher temperature, and therefore a hot melt coating method in which the heated and melted material is applied to the substrate from a T-die in a non-contact manner is preferred from the viewpoints of thickness control and uniformity of the pressure-sensitive adhesive layer and the heat resistance required for the substrate.

[0091] The substrate used here is not particularly limited as long as it has appropriate elasticity, flexibility, and strength, and is particularly preferably one having appropriate breathability, moisture permeability, and microbial barrier properties. Examples include films, foams, nonwoven fabrics, woven fabrics, knitted fabrics, etc., made of polyolefin, polyurethane, polyester, polyacrylic acid, etc. Among these, polyurethane films are preferred from the above-mentioned viewpoint.

[0092] If the thickness of the base material is less than 5 μm, the strength and handleability of the article comprising the adhesive layer (typically an adhesive sheet or film) will decrease, and for example, when used as a biological surface-adhering material, it will be difficult to apply to the skin and may tear due to contact with other members, etc., or may peel off from the skin in a short time due to contact with water in the bath, etc. Furthermore, if the thickness of the base material is too large (more than 1 mm), for example, when used as a biological surface-adhering material, it will be difficult to follow the movement of the skin, and peeling triggers will easily form at the edges of the article comprising the adhesive layer, which may cause peeling, and may result in peeling from the skin in a short time or an increased sense of discomfort during application.

[0093] The release sheet used may be one commonly used in the field of adhesive materials. For example, a paper substrate such as high-quality paper or glassine paper with a silicone release treatment, or a polyester film may be used. The basis weight of the release sheet is not limited, but is usually 50 to 150 g / m 2 The preferred range is 60 to 100 g / m 2A release sheet of this order is more preferable. Although a single release sheet may be used, by providing one or more linear release sheet dividing sections that divide the outer shape of the release sheet in the approximate center, even when one release sheet is peeled off, the other release sheet remains, and application can be performed without touching the adhesive surface, improving workability. When the adhesive material is in roll form, this is particularly effective in making the release sheet easier to peel off and improving handleability. In addition, when two or more release sheets are used, the adhesive contact To facilitate peeling from the adhesive, it is also effective to arrange a release sheet so as to cover one side or fold it back, thereby improving the handling property. The length of the release sheet is contact From the viewpoints of preventing the adhesive from leaking, productivity, ease of handling, economy, and ease of manufacturing, contact It is preferable that the area is larger than the area to be coated with the adhesive by 0.2 mm or more, particularly 1 to 5 mm.

[0094] When the article is used as a biological surface adhesive, the article may further contain a topically administrable pharmaceutically active agent. Examples of topically administrable pharmaceutically active agents include antibacterial agents, antifungal agents, anti-inflammatory agents (steroidal anti-inflammatory agents, nonsteroidal anti-inflammatory agents (NSAIDs), etc.), vitamins, active oils, moisturizers, etc. More specific topically administrable pharmaceutically active agents include, for example, iodine, povidone-iodine, silver, salicylic acid or a salt thereof, acetylsalicylic acid or a salt thereof, chlorhexidine (e.g., chlorhexidine gluconate), sulfacetamide and a salt thereof, erythromycin, neomycin, polymyxin, bacitracin, retapamulin, mupirocin, gentamicin, mafenide, lidocaine, tetracycline, benzoic acid, ciclopirox olamine, undecylenic acid alkanolamide, bifonazole, clotrimazole, etc. ol, econazole, ketoconazole, miconazole, tioconazole, terbinafine, tolciclate, tolnaftate, thymol, sulfacetamide, almond oil, argan oil, avocado oil, camelina oil, coconut oil, jojoba oil, rose oil, sesame oil, shea butter, hemp seed oil, macadamia nut oil, lanolin, vitamins such as vitamin A, vitamin A palmitate, vitamin B3, vitamin C, and tocopherol and its esters such as α-tocopherol and α-tocopherol acetate. The topically administrable pharmaceutically active agent can be contained in an appropriate amount in the article depending on its intended use. For example, the topically administrable pharmaceutically active agent can be used in an amount of 20 parts by mass or less, 15 parts by mass or less, 10 parts by mass or less, 5 parts by mass or less, 2 parts by mass or less, or 1 part by mass or less, relative to 100 parts by mass of the acrylic triblock copolymer (I) contained in the hydrocolloid pressure-sensitive adhesive composition.

[0095] [Wound dressing material] The above-mentioned article can be suitably used as a biological surface adhesive. The above-mentioned biological surface adhesive can be used, for example, in pharmaceutical and veterinary applications, and surgical treatment applications. For example, the biological surface adhesive can be used as a wound dressing used to cover a wound for wound treatment. In other words, the article can be a wound dressing having an adhesive layer containing the hydrocolloid adhesive composition.

[0096] Specific examples of the above-mentioned biological surface adhesive material include first-aid adhesive bandages (containing disinfectants), surgical dressings / surgical tapes, adhesive plasters, hemostatic tapes, suture tapes, antibacterial tapes, and the like.

[0097] Figure 2 shows a plan view and a cross-sectional view of a bandage-type wound dressing 200 according to one embodiment of the present invention. Figure 2(a) is a plan view seen from the release sheets 30a and 30b side, and Figure 2(b) is a cross-sectional view taken along the line IIB-IIB in Figure 2(a). 2(a) and 2(b), the wound dressing 200 has a pad layer 21 including an adhesive layer made of a hydrocolloid adhesive composition provided in the center of a substrate 10, and an adhesive layer 40 provided around the pad layer 21. A pair of release sheets 30a, 30b are provided to cover the pad layer 21 and the adhesive layer 40. The end of the release sheet 30b facing the pad layer 21 is folded back, and the end of the release sheet 30a facing the pad layer 21 is further folded back onto the folded back end. The user can sequentially peel off the release sheets 30a and 30b from the end located on the pad layer 21 to expose the pad layer 21 and the adhesive layer 40, which can then be applied to the target area, such as a wound.

[0098] The pad layer 21 is made of an optional flexible protective layer and an adhesive layer made of the hydrocolloid type adhesive composition. contact The pad layer 21 may be an embodiment comprising an adhesive layer and the hydrocolloid-type pressure-sensitive adhesive composition, or may be an embodiment comprising only a pressure-sensitive adhesive layer comprising the hydrocolloid-type pressure-sensitive adhesive composition. When the protective layer is present, the pad layer 21 may be formed by integrating a pre-formed protective layer with the pressure-sensitive adhesive layer comprising the hydrocolloid-type pressure-sensitive adhesive composition by adhesion or other methods, or the hydrocolloid-type pressure-sensitive adhesive composition may be extruded onto a flexible film to obtain the pad layer 21 integrated with the protective layer. The pad layer 21 may also be obtained by impregnating a fibrous or sponge-like pad material with the hydrocolloid-type pressure-sensitive adhesive composition.

[0099] In the laminate sheet 100 and the wound dressing 200, various conventionally known materials can be used as materials for the components other than the adhesive layer made of the hydrocolloid adhesive composition. For example, the substrate 10 can be made of the same materials and members as those described for the substrate constituting the above-mentioned article. Furthermore, the release materials 30, 30a, and 30b can be made of the same materials and members as those described for the release sheets constituting the above-mentioned article. The adhesive layer 40 can be made of, for example, an adhesive layer made of the adhesive composition comprising the above-mentioned acrylic block copolymer. [Example]

[0100] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In Production Examples 1 to 3 shown below, the monomers and other compounds were dried and purified by a conventional method and degassed with nitrogen before use. The transfer and supply of the monomers and other compounds to the reaction system were carried out under a nitrogen atmosphere. The melt-kneading of the block copolymer and the melt-kneading of the block copolymer with the water-absorbing agent (Z) were carried out under an air atmosphere.

[0101] In the following Production Examples, the weight average molecular weight (Mw), number average molecular weight (Mn), and molecular weight distribution (Mw / Mn) of the polymer (polymer forming the block) and the acrylic triblock copolymer were determined in terms of polystyrene by gel permeation chromatography (GPC). The measuring apparatus and conditions used in GPC are as follows: [GPC measurement equipment and conditions] Apparatus: Tosoh Corporation GPC apparatus "HLC-8020" Separation column: Tosoh Corporation's "TSKgel GMHXL" and "G4000HXL" and "G5000HXL" connected in series Eluent: Tetrahydrofuran Eluent flow rate: 1.0 ml / min Column temperature: 40℃ Detection method: Refractive index (RI)

[0102] In the following examples, the content of each polymer block in the block copolymer is 1 It was determined by H-NMR measurement. 1 The measurement equipment and conditions used for H-NMR measurement are as follows:

[0103] [ 1 H-NMR measurement equipment and conditions] Equipment: Nuclear magnetic resonance spectrometer "JNM-ECX400" manufactured by JEOL Ltd. Heavy solvent: deuterated chloroform 1 In the H-NMR spectrum, the signals at around 3.6 ppm and 4.0 ppm were assigned to a hydrogen atom (-O-CH3) bonded to a carbon atom adjacent to an oxygen atom contained in the ester group of a methyl methacrylate unit and a hydrogen atom (-O-CH2-CH2-CH2-CH3) bonded to a carbon atom adjacent to an oxygen atom contained in an ester group of an n-butyl acrylate unit, respectively, and the content of each polymer block was determined from the ratio of the integral values.

[0104] The adhesive tapes having an adhesive layer made of the adhesive composition obtained in the examples and comparative examples were evaluated by the following methods.

[0105] [Loop tack characteristics] An adhesive tape having a 300 μm thick adhesive layer produced by the method described below was formed into a loop having a width of 10 mm and a length of 100 mm in an atmosphere of 23°C and 50% RH, with the adhesive layer facing outward. A 25 mm wide polymethyl methacrylate (PMMA) plate (Delagrass A999, manufactured by Asahi Kasei Technoplus Corporation) was attached to a loop tack tester ("LT-1000" manufactured by ChemInstruments) in a direction intersecting the loop, and the tack value (maximum value when peeled) was measured according to the method described in PSTC-16, and the average value for three tests was calculated. If the loop tack value is less than 2, the adhesive tape will not exhibit good adhesiveness immediately after application, and will often have poor trackability. If the loop tack value exceeds 15, trackability tends to be high, but the tape will be difficult to re-apply and will likely cause pain when removed. From these perspectives, the loop tack value is preferably 2 to 15 N. Regarding the variability of physical properties, the average and standard deviation of three tests were calculated, and the coefficient of variation (CV) was calculated from these values. A CV of less than 15 was evaluated as pass (G), and a CV of 15 or more was evaluated as fail (NG).

[0106] [Pain when peeling from skin] Ten panelists (test subjects: adults in their 50s and 60s) were given adhesive tapes with a 300 μm thick adhesive layer prepared by the method described below, cut to a width of 10 mm and a length of 100 mm, and applied them to the inside of their forearms in an atmosphere of 23°C and 50% RH, pressing them with the palm of their hand for 10 seconds to form a tight seal. Ten minutes after application, the pain felt when the tape was removed by hand was evaluated on a four-point scale (0: no pain, 1: slight pain, 2: pain, 3: unbearable pain). The average of the scores given by each panelist in the sensory evaluation was used as the evaluation result.

[0107] [Water vapor permeability] A 300 μm thick pressure-sensitive adhesive layer (circular with a diameter of 70 mm) prepared by the method described below was set in a moisture permeable cup with a transmission part diameter of 60 mm, and the water vapor transmission rate was measured under conditions of 25°C and 50% RH in accordance with the JIS Z0208 cup method. The average value and standard deviation of two tests were calculated, and the coefficient of variation (CV) was calculated from these values. A CV of less than 10 was evaluated as a pass (G), and a CV of 10 or more was evaluated as a fail (NG).

[0108] [Moisture content] With reference to JIS K7251 Method B, samples with sides of 2 to 4 mm were conditioned for 24 hours or more at 25°C and 50% RH, and then the moisture content (the ratio of the mass of moisture to the total mass of the sample after conditioning (mass%)) was measured using a Karl Fischer moisture meter MKC-510N (Kyoto Electronics Manufacturing Co., Ltd.) and a moisture vaporizer ADP-511 at a vaporization temperature of 130°C in a nitrogen gas atmosphere. The average and standard deviation of two tests were calculated, and the coefficient of variation was calculated from these values. A coefficient of variation of less than 5 was evaluated as passing (G), and a coefficient of variation of 5 or more was evaluated as failing (NG).

[0109] <Production Example 1> Production of acrylic triblock copolymer (I-1) (1) A three-way cock was attached to a 3 L three-neck flask, and the inside of the flask was replaced with nitrogen. Then, with stirring at room temperature, 1,409 g of toluene and 32.7 g of 1,2-dimethoxyethane were added, followed by 48.6 g of a toluene solution containing 24.5 mmol of isobutylbis(2,6-di-t-butyl-4-methylphenoxy)aluminum, and then 1.50 g of a cyclohexane solution of sec-butyllithium containing 2.55 mmol of sec-butyllithium. (2) Subsequently, 22.7 g of methyl methacrylate was added to the reaction mixture. The reaction mixture was initially yellow, but after stirring at room temperature for 60 minutes, it became colorless. (3) Subsequently, the internal temperature of the polymer solution was cooled to -30°C, and 434 g of n-butyl acrylate was added dropwise over 2 hours. After the dropwise addition was completed, the mixture was stirred at -30°C for 5 minutes. (4) Further, 29.4 g of methyl methacrylate was added to this, and the mixture was stirred overnight at room temperature. (5) After 15 g of methanol was added to terminate the polymerization reaction, the resulting reaction solution was poured into 15 kg of methanol to precipitate a liquid precipitate. The liquid precipitate was then collected and dried to obtain 440 g of an acrylic triblock copolymer (I-1). The weight-average molecular weight (Mw) of the resulting acrylic triblock copolymer (I-1) was determined by GPC measurement using the method described above. 1The total content of polymer blocks composed of methyl methacrylate units in the acrylic triblock copolymer (I-1) was determined by H-NMR measurement.

[0110] <Production Example 2> Production of acrylic triblock copolymer (I-2) (1) A three-way cock was attached to a 3 L three-neck flask, and the inside of the flask was replaced with nitrogen. Then, with stirring at room temperature, 1,302 g of toluene and 65.1 g of 1,2-dimethoxyethane were added, followed by 120.0 g of a toluene solution containing 60.3 mmol of isobutylbis(2,6-di-t-butyl-4-methylphenoxy)aluminum, and then 4.34 g of a cyclohexane solution of sec-butyllithium containing 7.50 mmol of sec-butyllithium. (2) Subsequently, 53.9 g of methyl methacrylate was added to the reaction mixture. The reaction mixture was initially yellow, but after stirring at room temperature for 60 minutes, it became colorless. (3) Subsequently, the internal temperature of the polymer solution was cooled to -30°C, and 360 g of n-butyl acrylate was added dropwise over 2 hours. After the addition was completed, the mixture was stirred at -30°C for 5 minutes. (4) Further, 53.9 g of methyl methacrylate was added to this, and the mixture was stirred overnight at room temperature. (5) After 20 g of methanol was added to terminate the polymerization reaction, the resulting reaction solution was poured into 15 kg of methanol to precipitate a liquid precipitate. The liquid precipitate was then collected and dried to obtain 440 g of an acrylic triblock copolymer (I-2). The weight-average molecular weight (Mw) of the resulting acrylic triblock copolymer (I-2) was determined by GPC measurement using the method described above. 1 The total content of polymer blocks composed of methyl methacrylate units in the acrylic triblock copolymer (I-2) was determined by H-NMR measurement.

[0111] <Production Example 3> Production of acrylic triblock copolymer (II-1) (1) A three-way cock was attached to a 3 L three-neck flask, and the inside of the flask was replaced with nitrogen. Then, with stirring at room temperature, 1,409 g of toluene and 32.7 g of 1,2-dimethoxyethane were added, followed by 48.6 g of a toluene solution containing 24.5 mmol of isobutylbis(2,6-di-t-butyl-4-methylphenoxy)aluminum, and then 4.50 g of a cyclohexane solution of sec-butyllithium containing 7.65 mmol of sec-butyllithium. (2) Subsequently, 30.1 g of methyl methacrylate was added to the mixture. The reaction mixture was initially yellow, but after stirring at room temperature for 60 minutes, it became colorless. A small amount was sampled, and the weight-average molecular weight of the resulting polymethyl methacrylate was determined by GPC measurement using the method described above. (3) Subsequently, the internal temperature of the polymer solution was cooled to -30°C, and 427 g of n-butyl acrylate was added dropwise over 2 hours. After the addition was completed, the mixture was stirred at -30°C for 5 minutes. (4) Further, 7.60 g of methyl methacrylate was added to this, and the mixture was stirred overnight at room temperature. (5) After 20 g of methanol was added to terminate the polymerization reaction, the resulting reaction solution was poured into 15 kg of methanol to precipitate a liquid precipitate. The liquid precipitate was then recovered and dried to obtain 440 g of an acrylic triblock copolymer (II-1). The weight-average molecular weight of the resulting acrylic triblock copolymer (II-1) was determined by GPC measurement using the method described above. 1 The total content of polymer blocks composed of methyl methacrylate units in the acrylic triblock copolymer (II-1) was determined by H-NMR measurement.

[0112] The compositions and physical properties of the acrylic block copolymers obtained in Production Examples 1 to 3 are shown in Table 1.

[0113] [Table 1]

[0114] In the examples and comparative examples, the following tackifier resins, water absorbents, antioxidants and substrates were used. (tackifying resin) Product name: "Foral 85E" manufactured by Eastman, hydrogenated rosin ester Product name: "YSresin SX100" manufactured by Yasuhara Chemical Co., Ltd., aromatic hydrocarbon resin Product name: ARKON P90, hydrogenated petroleum resin manufactured by Arakawa Chemical Industries, Ltd. (Water absorbent (Z)) Product name: "Cellogen F-3H" manufactured by Daiichi Kogyo Seiyaku Co., Ltd., carboxymethyl cellulose (antioxidant) Product name: "ADK STAB AO-60" manufactured by ADECA (base material) Polyethylene terephthalate film: Toyobo Ester Film E5000, thickness 50 μm

[0115] <Examples 1 to 3> According to the composition of the hydrocolloid-type pressure-sensitive adhesive composition and the kneading temperature of the kneader shown in Table 2, the acrylic triblock copolymer (I-1) or (I-2) was introduced into a kneader and melted uniformly, and then the acrylic triblock copolymer (II-1) and the water-absorbing agent were introduced and melt-kneaded to make the mixture uniform, thereby preparing a pressure-sensitive adhesive composition. The obtained pressure-sensitive adhesive composition was sandwiched between two Teflon sheets (thickness 1 mm, "Teflon" is a registered trademark), and then kneaded at the same temperature as the melt-kneading temperature and a pressing pressure of 50 kgf / cm. 2 The mixture was press-molded under the conditions above to prepare a sheet having a thickness of 300 μm. For samples to be subjected to the loop tack evaluation and the evaluation of pain when peeled from the skin, a sheet having a thickness of 50 μm on one side and a thickness of 300 μm of the adhesive layer was prepared by press molding in the same manner as described above, except that the composition was a Teflon sheet (thickness 1 mm) / PET base material (50 μm) / adhesive composition / Teflon sheet (thickness 1 mm). Using the methods described above, the loop tack property, water vapor transmission rate, and moisture content were measured, and the pain felt when peeling the patch from the skin was evaluated.

[0116] <Examples 4 and 5> The hydrocolloid type adhesives listed in Table 2 contact According to the composition of the adhesive composition and the kneading temperature of the kneader, the acrylic triblock copolymer (I-1) is introduced into the kneader and melted uniformly, and then the acrylic triblock copolymer (II-1), the tackifier resin, and the water-absorbing agent are introduced, and the mixture is melt-kneaded until it becomes uniform. contact The adhesive composition obtained was contact The adhesive composition was prepared in the same manner as in Examples 1 to 3 into a 300 μm thick sheet and an adhesive tape having a 50 μm thick PET film on one side for loop tack evaluation and evaluation of pain when peeled from the skin. contact arrival Agent A sheet with a layer thickness of 300 μm was prepared. Using the methods described above, the loop tack property, water vapor permeability, moisture content, and pain when peeled from the skin were evaluated.

[0117] <Comparative Example 1> The hydrocolloid type adhesives listed in Table 2 contact According to the composition of the adhesive composition and the kneading temperature of the kneader, a styrene triblock copolymer (SIS5229 manufactured by JSR Corporation) and an antioxidant, Adekastab AO-60, were put into the kneader and melted uniformly. Then, a tackifying resin and a water-absorbing agent were added and melt-kneaded until the mixture was uniform. contact The adhesive composition obtained was contact The adhesive composition was prepared in the same manner as in Examples 1 to 3 into a 300 μm thick sheet and an adhesive tape having a 50 μm thick PET film on one side for loop tack evaluation and evaluation of pain when peeled from the skin. contact arrival Agent A sheet with a layer thickness of 300 μm was prepared. Using the methods described above, the loop tack property, water vapor permeability, moisture content, and pain when peeled from the skin were evaluated.

[0118] [Table 2]

[0119] As shown in Table 2, a hydrocolloid type adhesive containing an acrylic block copolymer and a water-absorbing agent was used. contactThe pressure-sensitive adhesive sheets of Examples 1 to 5, which are made of adhesive compositions, have small variations in loop tack property, moisture content, and water vapor permeability, and have uniform adhesive properties. contact It can be seen that adhesive compositions were obtained. Furthermore, their loop tackiness was moderate, indicating that they had good loop tackiness properties (i.e., the ability to conform to the surface to which they are applied and gently adhere). Furthermore, it can be seen that these pressure-sensitive adhesive sheets had high moisture content and water vapor permeability, and did not cause pain when peeled from the skin.

[0120] On the other hand, Comparative Example 1, which used a styrene triblock copolymer instead of an acrylic block copolymer, had low water vapor permeability, and it was found that there was slight pain when the wound dressing was peeled off. [Industrial Applicability]

[0121] The hydrocolloid adhesive composition of the present invention can be suitably used to form adhesive layers of materials for attachment to biological surfaces in pharmaceutical and veterinary applications, surgical treatment applications, and the like. Furthermore, an article having an adhesive layer containing the hydrocolloid adhesive composition of the present invention can be suitably used as a biological surface adhesive material in pharmaceutical and veterinary applications, surgical treatment applications, and the like. Furthermore, the wound dressing of the present invention is used by applying it to a living body so as to cover a wound in order to treat the wound. [Explanation of symbols]

[0122] 10: Base material 20: Adhesive layer made of a hydrocolloid type adhesive composition 21: Pad layer 30, 30a, 30b: release sheet 40:Adhesive layer 100: Laminated sheet 200: Bandage-type wound dressing

Claims

1. Contains an acrylic block copolymer and a water-absorbing agent (Z), The acrylic block copolymer includes an acrylic triblock copolymer (I) and an acrylic triblock copolymer (II), the acrylic triblock copolymer (I) has two polymer blocks (A1) and (A2) each consisting of a methacrylic acid ester unit and one polymer block (B) each consisting of an acrylic acid ester unit, and has an (A1)-(B)-(A2) block structure; In the acrylic triblock copolymer (I), the total content of the polymer blocks (A1) and (A2) is 4 to 35% by mass, and the content of the polymer block (B) is 65 to 96% by mass; the acrylic triblock copolymer (II) has at least two polymer blocks (C1) and (C2) each consisting of a methacrylic acid ester unit, and at least one polymer block (D) each consisting of an acrylic acid ester unit, and has a (C1)-(D)-(C2) block structure; In the acrylic triblock copolymer (II), the total content of the polymer blocks (C1) and (C2) is 5 to 25% by mass, and the content of the polymer block (D) is 75 to 95% by mass, a hydrocolloid-type pressure-sensitive adhesive composition, wherein the weight average molecular weights of the two polymer blocks (C1) and (C2) are both smaller than the weight average molecular weights of the polymer blocks (A1) and (A2) contained in the acrylic triblock copolymer (I).

2. 2. The hydrocolloid pressure-sensitive adhesive composition according to claim 1, wherein the water-absorbing agent (Z) is at least one selected from the group consisting of polysaccharides or derivatives thereof; polyacrylic acid or a salt thereof; polyethylene oxide; polyvinyl alcohol; protein; and poly-N-vinylpyrrolidone.

3. 3. The hydrocolloid pressure-sensitive adhesive composition according to claim 1, wherein the water-absorbing agent (Z) is contained in an amount of 5 to 50 mass % based on the total mass of the hydrocolloid pressure-sensitive adhesive composition.

4. The hydrocolloid pressure-sensitive adhesive composition according to any one of claims 1 to 3, wherein the acrylic block copolymer comprises the acrylic triblock copolymer (I) and the acrylic triblock copolymer (II) in a mass ratio of 100:1 to 100:

500.

5. The hydrocolloid pressure-sensitive adhesive composition according to any one of claims 1 to 4, wherein the total content of methacrylic acid ester units in the acrylic block copolymer is 4 to 35 mass%.

6. An article having a substrate and an adhesive layer comprising the hydrocolloid adhesive composition according to any one of claims 1 to 5.

7. A wound dressing comprising a substrate and an adhesive layer comprising the hydrocolloid adhesive composition according to any one of claims 1 to 5.

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