Adhesive sheet to be stuck to skin

Abstract

To provide an adhesive sheet to be stuck to skin, including an adhesive agent layer formed from an acrylic hot-melt adhesive agent, and capable of achieving in good balance performance suitable for use for sticking to skin.SOLUTION: An adhesive sheet to be stuck to skin includes an adhesive agent layer formed from an acrylic hot-melt adhesive agent containing an acrylic block copolymer and a plasticizer. The acrylic block copolymer has a soft block and a hard block. In a monomer component constituting the soft block, a content of alkyl acrylate having an acryl group having 6 to 12 carbon atoms is 40 wt.% or more. The plasticizer includes a plasticizer having an HLB of 0.5 or more and 3 or less.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an adhesive sheet for skin attachment.

Background Art

[0002] In the medical field, sports field, beauty field, etc., for example, for the purpose of fixing a medical device or other measuring device to the skin surface, protecting or decorating the skin surface, etc., an adhesive sheet for skin attachment may be used. An adhesive sheet for skin attachment is desirably capable of exhibiting good adhesiveness and fixability to the skin, and having a performance that can be peeled off while suppressing damage to the skin and adhesive residue. As prior art documents related to adhesives or adhesive tapes for use in applications attached to the skin, Patent Documents 1 and 2 can be cited.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the specific examples disclosed in Patent Documents 1 and 2, in both cases, an adhesive layer is formed using a solvent - type acrylic - based adhesive composition. On the other hand, in recent years, from the viewpoints of environmental hygiene, etc., the use of a solvent - free adhesive composition has been preferred. Also in the field of adhesive sheets for skin attachment, it would be useful if an adhesive sheet could be provided that can be manufactured using a solvent - free adhesive composition, for example, a hot - melt type adhesive composition, instead of the conventional solvent - type acrylic - based adhesive composition, and can exhibit desired performance.

[0005] Therefore, an object of the present invention is to provide an adhesive sheet for skin attachment, which is provided with an adhesive layer formed of an acrylic hot-melt adhesive and can well balance the performance suitable for skin attachment applications.

Means for Solving the Problems

[0006] The adhesive sheet for skin attachment provided by this specification includes an adhesive layer formed of an acrylic hot-melt adhesive containing an acrylic block copolymer and a plasticizer. The acrylic block copolymer has a soft block and a hard block. The monomer component constituting the soft block is an alkyl acrylate (hereinafter also referred to as C 6-12 alkyl acrylate.) with the carbon number of the alkyl group being 6 to 12 and the content thereof being 40% by weight or more. The plasticizer includes a plasticizer with an HLB of 0.5 or more and 3 or less. C 6-12 According to an adhesive layer containing a combination of an acrylic block copolymer having a soft block with a content of C alkyl acrylate of 40% by weight or more and a plasticizer with an HLB of 0.5 or more and 3 or less, an adhesive sheet for skin attachment can be realized that well balances good adhesiveness and fixability to the skin and good peelability from the skin (for example, the performance that can be peeled off while suppressing damage to the skin and adhesive residue). As the plasticizer, for example, a fatty acid ester with an HLB in the above range can be preferably used.

[0007] In some embodiments, it is preferable that the adhesive layer contains an adhesion-imparting resin. By using the adhesion-imparting resin, the adhesiveness and fixability to the skin can be improved. Considering the balance with good peelability from the skin, the amount of the adhesion-imparting resin used per 100 parts by weight of the acrylic block copolymer is, for example, appropriately 60 parts by weight or more and 150 parts by weight or less.

[0008] In some embodiments, it is preferable that the tackifier resin contains a tackifier resin having a softening point of 60°C or higher and 120°C or lower. According to the tackifier resin having a softening point within the above range, it is easy to improve the adhesiveness and fixability to the skin while suppressing the influence on the good peelability from the skin.

[0009] In some embodiments, the content of the plasticizer in the pressure-sensitive adhesive layer is preferably 60 parts by weight or more and 150 parts by weight or less with respect to 100 parts by weight of the acrylic block copolymer. By setting the content of the plasticizer within the above range, it is possible to realize a pressure-sensitive adhesive sheet for skin application that more preferably achieves both good adhesiveness and fixability to the skin and good peelability from the skin.

[0010] The pressure-sensitive adhesive sheet for skin application disclosed herein may include a base material that supports the pressure-sensitive adhesive layer. The configuration in which the pressure-sensitive adhesive sheet for skin application has a base material can be advantageous from the viewpoints of the handleability and processability of the pressure-sensitive adhesive sheet.

[0011] In addition, a combination of each element described in this specification as appropriate may also be included in the scope of the invention for which patent protection is sought by this patent application.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Mode for Carrying Out the Invention

[0013] Hereinafter, preferred embodiments of the present invention will be described. In addition, matters other than those specifically mentioned in this specification and necessary for the implementation of the present invention can be understood by those skilled in the art based on the teachings regarding the implementation of the invention described in this specification and the common general knowledge in the art at the time of filing. The present invention can be implemented based on the content disclosed in this specification and the common general knowledge in the relevant field. Also, in the following drawings, members and parts having the same function may be denoted by the same reference numerals for explanation, and duplicate explanations may be omitted or simplified. Further, the embodiments shown in the drawings are schematized for clearly explaining the present invention and do not necessarily accurately represent the size and scale of the actually provided product.

[0014] In this specification, the “acrylic monomer” refers to a monomer having at least one (meth)acryloyl group in one molecule. Here, the “(meth)acryloyl group” means comprehensively referring to an acryloyl group and a methacryloyl group. Therefore, the concept of the acrylic monomer referred to here may include both a monomer having an acryloyl group (acrylic monomer) and a monomer having a methacryloyl group (methacrylic monomer). Similarly, in this specification, “(meth)acrylic acid” means comprehensively referring to acrylic acid and methacrylic acid, and “(meth)acrylate” means comprehensively referring to acrylate and methacrylate. The same applies to other similar terms.

[0015] In this specification, the “base polymer” of an adhesive refers to the main component in the polymer components contained in the adhesive. The same applies to the case of referring to the “base polymer” for other materials, which means the main component contained in the material. Also, in this specification, the “main component” refers to a component contained in an amount exceeding 50% by weight unless otherwise specified.

[0016] Fig. 1 shows a configuration example of the adhesive sheet for skin attachment disclosed herein. The adhesive sheet 1 for skin attachment according to this embodiment includes an adhesive layer 10 and a base material 20, and is configured as a single-sided adhesive sheet (single-sided adhesive sheet with a base material) in which one surface 10A of the adhesive layer 10 serves as a sticking surface (adhesive surface) to an adherend. The other surface 10B of the adhesive layer 10 is fixed to the first surface 20A of the base material 20. The adhesive sheet 1 for skin attachment is used by sticking the adhesive surface 10A to the skin (adherend). Before use (before attachment to the adherend), the adhesive sheet 1 may be in the form of an adhesive sheet 50 with a release liner in which the adhesive surface 10A is protected by a release liner 30 having at least the adhesive layer side as a releasable surface (release surface), as shown in Fig. 1 for example. Alternatively, without using the release liner 30, the second surface 20B of the base material 20 (the surface opposite to the first surface 20A, also referred to as the back surface) serves as the release surface, and the adhesive surface 10A may be protected by winding or laminating the adhesive surface 10A so as to abut on the second surface 20B.

[0017] The adhesive sheet for skin attachment disclosed herein may be in the form of a substrate-free double-sided adhesive sheet composed of an adhesive layer 10, such as the adhesive sheet 2 for skin attachment shown in FIG. 2. In the adhesive sheet 2 according to this embodiment, both the one surface 10A and the other surface 10B of the adhesive layer 10 are adhesive surfaces. Before use, the adhesive sheet 2 may be in a form in which each surface 10A, 10B of the adhesive layer 10 is protected by release liners 31, 32 at least on the adhesive layer side, which serves as a release surface. Alternatively, without using the release liner 32, the back surface (the surface opposite to the adhesive side) of the release liner 31 serves as a release surface, and the adhesive surfaces 10A, 10B are protected by winding or laminating the adhesive surface 10B in contact with the back surface. Further, the adhesive sheet for skin attachment disclosed herein may be in the form of a double-sided adhesive sheet with a substrate in which an adhesive layer is laminated on each of the first surface and the second surface of a sheet-like substrate. Such an adhesive sheet for skin attachment in the form of a substrate-free or substrate-attached double-sided adhesive sheet (double-sided adhesive sheet) is used by attaching at least one adhesive surface to the skin (adherend). The other adhesive surface of the double-sided adhesive sheet may be attached to the skin or may be attached to an adherend other than the skin. Further, a single-sided adhesive sheet with a substrate may be formed by laminating a substrate on the other adhesive surface of the substrate-free double-sided adhesive sheet.

[0018] <Adhesive layer> (Acrylic block copolymer) The adhesive sheet for skin attachment disclosed herein has an adhesive layer formed of an acrylic hot-melt adhesive containing an acrylic block copolymer and a plasticizer. The acrylic block copolymer may exhibit the properties of a thermoplastic polymer (typically a thermoplastic elastomer). The adhesive layer preferably contains an acrylic block copolymer as a base polymer. An adhesive containing an acrylic block copolymer as a base polymer can be suitable for coating in a hot-melt form. Using a hot-melt adhesive for forming the adhesive layer is preferable from the viewpoint of reducing the environmental load. From the viewpoint of reducing the melt viscosity, a linear acrylic block copolymer is advantageous compared to a star structure or a branched structure.

[0019] As the acrylic block copolymer, those having a structure containing at least one hard block composed of a polymer with a hard structure excellent in cohesive force and elasticity and at least one soft block composed of a polymer with a soft structure excellent in viscosity are used. The acrylic block copolymer can be copolymerized such that the hard block (A block) and the soft block (B block) are alternately arranged, such as in the AB type, ABA type, ABAB type, ABABA type, etc. An adhesive using an acrylic block copolymer having such a structure as a base polymer can form an adhesive layer that highly balances cohesive force, elasticity, and viscosity. Further, an adhesive having such a composition can be preferably used as a hot-melt type adhesive. An acrylic block copolymer mainly composed of a polymer having a structure in which hard blocks are arranged at both ends of the molecule (ABA type, ABABA type, etc.) can be preferably adopted. Among them, an acrylic block copolymer mainly composed of an ABA type polymer is preferred.

[0020] The monomer component constituting the soft block has a content of an alkyl acrylate having 6 to 12 carbon atoms in the alkyl group of 40% by weight or more. Here, the alkyl acrylate having 6 to 12 carbon atoms in the alkyl group means an alkyl acrylate having a chain alkyl group having 6 to 12 carbon atoms at the ester terminal, that is, the following formula: CH2=CHCOOR 1 ; in which R1 is a chain alkyl group having 6 to 12 carbon atoms. Hereinafter, an alkyl acrylate having X to Y carbon atoms is referred to as "C" X-YIt may be referred to as "alkyl acrylate". According to the acrylic block copolymer having a soft block formed by the monomer component having such a composition, in combination with a predetermined plasticizer, while suppressing the decrease in cohesiveness caused by the plasticizer, it can form an adhesive showing flexibility that can be well adhered to the micro unevenness that may exist on the skin surface. By this, it is possible to suitably realize a skin-adhesive sheet that well balances good adhesiveness and fixability to the skin and good peelability from the skin. From the viewpoint of improving flexibility (and thus adhesiveness to the skin), in some embodiments, C in the monomer component constituting the above soft block 6-12 The content of alkyl acrylate is preferably 45% by weight or more (for example, approximately 50% by weight or more or more than 50% by weight), more preferably 60% by weight or more, and may be 70% by weight or more, 80% by weight or more, 90% by weight or more, 95% by weight or more, or even 100% by weight. Also, the monomer component constituting the above soft block contains C 7-10 alkyl acrylate preferably, and 8-10 more preferably contains alkyl acrylate.

[0021] The C 6-12 alkyl acrylate contained in the monomer component constituting the above soft block may be one type or two or more types. 6-12Specific examples of the alkyl acrylate include, but are not limited to, n-hexyl acrylate, n-heptyl acrylate, 2-ethylhexyl acrylate (2EHA), n-octyl acrylate, isooctyl acrylate, n-nonyl acrylate, isononyl acrylate, n-decyl acrylate, isodecyl acrylate, 2-octyl acrylate, n-undecyl acrylate, n-lauryl acrylate, etc. The technology disclosed herein can be preferably implemented using, for example, an acrylic block copolymer having a soft block formed from a monomer component containing 2EHA in any of the above-described contents (typically 40% by weight or more, preferably 45% by weight or more, for example, approximately 50% by weight or more or more than 50% by weight).

[0022] The monomer component constituting the soft block is C 6-12 In addition to the alkyl acrylate, other monomers may be included. Examples of the other monomers include C 6-12 alkyl (meth) acrylates not corresponding to the alkyl acrylate (for example, C 6-12 alkyl (meth) acrylates not corresponding to the alkyl acrylate having C 1-20 ). For example, the other monomers may preferably be one or more selected from the group consisting of C 1-3 alkyl (meth) acrylate, C 4-5 alkyl (meth) acrylate, C 13-20 alkyl (meth) acrylate, and C 6-12 alkyl methacrylate. Specific examples of the C 6-12 alkyl (meth) acrylate not corresponding to the alkyl acrylate include, but are not limited to, n-butyl acrylate (BA), lauryl methacrylate, isostearyl acrylate, etc. In the monomer component constituting the soft block, the content of the C 1-20 alkyl (meth) acrylate not corresponding to the alkyl acrylate is C 6-12 alkyl (meth) acrylate not corresponding to the alkyl acrylate is C 1-20 alkyl (meth) acrylate is C 6-12It is set so that the total amount with the alkyl acrylate does not exceed 100% by weight, and can be, for example, 60% by weight or less, 55% by weight or less, 50% by weight or less, less than 50% by weight, 40% by weight or less, 30% by weight or less, 20% by weight or less, 10% by weight or less, or 5% by weight or less.

[0023] In one aspect, as the acrylic block copolymer, C 6-12 alkyl acrylate (for example, 2EHA) and C 2-5 It is preferable to preferably employ a monomer component having a weight ratio of alkyl acrylate (for example, BA) of 30 / 70 to 100 / 0 (more preferably 40 / 60 to 100 / 0, still more preferably 50 / 50 to 100 / 0, for example 60 / 40 to 100 / 0) to form a soft block. Such an acrylic block copolymer is suitable for forming an adhesive having an excellent balance between flexibility and cohesiveness. For example, an acrylic block copolymer having a soft block composed of 2EHA or a monomer component containing 2EHA and BA in the above weight ratio is preferable.

[0024] In some aspects, from the viewpoint of improving flexibility, it is appropriate that the glass transition temperature (Tg) determined by Fox's equation based on the composition of the monomer components constituting the soft block is -40°C or lower, advantageously -50°C or lower, preferably lower than -55°C, more preferably -58°C or lower, may be -60°C or lower, or may be -62°C or lower or -65°C or lower. The lower limit of Tg (hereinafter sometimes referred to as "Tg S ") based on the monomer composition of the soft block is not particularly limited and can be, for example, -80°C or higher or -75°C or higher.

[0025] Here, Fox's equation is, as shown below, a relational equation between the Tg of the copolymer and the glass transition temperature Tgi of each of the homopolymers obtained by homopolymerizing the monomers constituting the copolymer. 1 / Tg = Σ(Wi / Tgi) In the above formula of Fox, Tg represents the glass transition temperature of the copolymer (unit: K), Wi represents the weight fraction of monomer i in the copolymer (copolymerization ratio based on weight), and Tgi represents the glass transition temperature of the homopolymer of monomer i (unit: K). When the target polymer related to the specification of Tg is a homopolymer, the Tg of the homopolymer coincides with the Tg of the target polymer.

[0026] As the glass transition temperature of the homopolymer used for calculating Tg, the values described in known materials shall be used. For example, the value of the glass transition temperature of the homopolymer of 2-ethylhexyl acrylate (2EHA) is -70 °C, and the value of the glass transition temperature of the homopolymer of n-butyl acrylate (BA) is -55 °C. For the glass transition temperature of the homopolymer of monomers other than those exemplified above, the numerical values described in "Polymer Handbook" (3rd Edition, John Wiley & Sons, Inc., 1989) shall be used. When multiple types of values are described in this document, the highest value shall be adopted.

[0027] The hard block contained in the acrylic block copolymer is a block that is relatively hard in contrast to the above soft block. The Tg (hereinafter, sometimes referred to as "Tg H ") obtained by Fox's formula based on the composition of the monomer components constituting the hard block is preferably 10 °C or higher than the Tg (that is, Tg S ) obtained by Fox's formula based on the composition of the monomer components constituting the soft block. That is, the above acrylic block copolymer preferably satisfies the following formula: 10 °C ≤ (Tg H [°C] - Tg S [°C]); From the viewpoint of preferably achieving both flexibility suitable for adhesion to the skin and cohesiveness suitable for fixing to the skin and preventing glue residue during peeling, in some embodiments, Tg H [°C] - Tg SThe value of [℃] is preferably 50 °C or higher, more preferably 100 °C or higher, may be 130 °C or higher, and may be 150 °C or higher, 160 °C or higher, 165 °C or higher, or 170 °C or higher.

[0028] In some embodiments, the monomer component constituting the hard block is C 1-3 The content of alkyl methacrylate is preferably 40% by weight or more. The technology disclosed herein can be preferably implemented using an acrylic block copolymer having a hard block with such a composition and the soft block described above. C in the monomer component constituting the hard block 1-3 The content of alkyl methacrylate is more preferably 45% by weight or more, further preferably 50% by weight or more (for example, more than 50% by weight) or 60% by weight or more, may be 70% by weight or more, may be 80% by weight or more, may be 90% by weight or more, may be 95% by weight or more, or may be 100% by weight.

[0029] C contained in the monomer component constituting the hard block 1-3 Alkyl methacrylate may be one type or two or more types. The monomer component constituting the hard block is C 1-3 The alkyl methacrylate preferably contains at least one of methyl methacrylate (MMA) and ethyl methacrylate, and more preferably contains at least MMA. In some preferred embodiments, the monomer component constituting the hard block contains MMA at any of the above-described contents (typically 40% by weight or more, preferably 45% by weight or more, for example, 50% by weight or more). In a preferred embodiment, the hard block is a block composed of MMA.

[0030] The weight ratio of the hard block to the soft block in the acrylic block copolymer is not particularly limited and can be, for example, in the range of 1 / 99 to 70 / 30. From the viewpoint of improving the flexibility of the adhesive, in some embodiments, the weight ratio of the hard block to the soft block is preferably 50 / 50 or less, more preferably 40 / 60 or less, and may be 30 / 70 or less, 25 / 75 or less, 20 / 80 or less, 15 / 85 or less, or 10 / 90 or less. Also, from the viewpoint of easily obtaining an adhesive having appropriate cohesiveness, in some embodiments, the weight ratio of the hard block to the soft block is preferably 2 / 98 or more, and more preferably 4 / 96 or more (for example, 5 / 95 or more). In an acrylic block copolymer containing two or more hard blocks, it is preferable that the weight ratio of the total weight of these hard blocks to the soft block is within the above range. The same applies to an acrylic block copolymer containing two or more soft blocks.

[0031] Incidentally, the composition of the monomer components constituting the acrylic block copolymer can be grasped based on the results of NMR measurement. Specifically, the above NMR measurement can be performed, for example, under the following conditions using "AVAVCEIII-600 (with Cryo Probe)" manufactured by Bruker Biospin as an NMR apparatus. For example, the weight ratio of 2EHA and MMA contained in the monomer raw material can be 1 calculated based on the peak integral intensity ratio of 4.0 ppm (2EHA1) and 3.6 ppm (MMA1) in the 1H NMR spectrum. [NMR Measurement Conditions] Observation frequency: 1 1H; 600 MHz Flip angle: 30° Measurement solvent: CDCl3 Measurement temperature: 300 K Chemical shift standard: Measurement solvent (CDCl3, 1 1H: 7.25 ppm)

[0032] The Mw of the acrylic block copolymer is not particularly limited, and can be, for example, 3×10 4 ~50×10 4 or so. From the viewpoint of easily obtaining an adhesive having appropriate cohesiveness, in some embodiments, the Mw of the acrylic block copolymer is preferably 5×10 4 or more, more preferably 7×10 4 or more, still more preferably 8×10 4 or more, 9×10 4 or more, 10×10 4 or more. Also, from the viewpoint of coatability in hot melt coating, in some embodiments, the Mw of the acrylic block copolymer is suitably 40×10 4 or less, preferably 35×10 4 or less, may be 30×10 4 or less, may be 25×10 4 or less, may be 20×10 4 or less, or 15×10 4 or less. Note that the Mw of the acrylic block copolymer referred to here means a polystyrene-equivalent value obtained by performing gel permeation chromatography (GPC) on a sample prepared by dissolving the copolymer in tetrahydrofuran (THF). Specifically, the above GPC measurement can be performed under the following conditions, for example, using "HLC-8120GPC" manufactured by Tosoh Corporation as a GPC measuring device. The Mw of other polymers and the oligomers described later can also be measured in the same manner. [GPC Measurement Conditions] · Column: TSKgel SuperHZM-H / HZ4000 / HZ3000 / HZ2000 manufactured by Tosoh Corporation · Column size: Each 6.0 mm I.D. × 150 mm · Eluent: THF · Flow rate: 0.6 mL / min · Detector: Differential refractometer (RI) · Column temperature (measurement temperature): 40°C · Sample concentration: Approximately 2.0 g / L (THF solution) · Sample injection volume: 20 μL

[0033] In the acrylic block copolymer, monomers other than alkyl (meth)acrylate (other monomers) may be copolymerized. Examples of the other monomers include vinyl compounds having functional groups such as alkoxy group, epoxy group, hydroxyl group, amino group, amide group, cyano group, carboxy group, acid anhydride group, vinyl esters such as vinyl acetate, aromatic vinyl compounds such as styrene, vinyl group-containing heterocyclic compounds such as N-vinylpyrrolidone, and the like. The content of the other monomers may be approximately 20% by weight or less, approximately 10% by weight or less, or approximately 5% by weight or less of all the monomer components constituting the acrylic block copolymer. In a preferred embodiment, the acrylic block copolymer substantially does not contain the other monomers. For example, an acrylic block copolymer in which the content of the other monomers is less than 1% by weight (typically 0 to 0.5% by weight) or below the detection limit of all the monomer components is preferred.

[0034] The acrylic block copolymer as described above can be easily synthesized by a known method (for example, refer to JP-A-2001-234146 and JP-A-11-323072), or a commercially available product can be easily obtained. Examples of the commercially available products include the product name "Clarity" series (for example, LK9243) manufactured by Kuraray Co., Ltd.

[0035] (Plasticizer) The pressure-sensitive adhesive sheet for skin attachment disclosed herein includes a pressure-sensitive adhesive layer containing a plasticizer in addition to the above acrylic block copolymer. The plasticizer can help enhance the flexibility of the pressure-sensitive adhesive and improve the adhesion to the skin. Examples of plasticizers include fatty acid esters, higher alcohols, dicarboxylic acid esters (e.g., phthalic acid diesters such as dioctyl phthalate, diisononyl phthalate, diisodecyl phthalate, dibutyl phthalate, etc.; adipic acid diesters such as dioctyl adipate, diisononyl adipate, etc.; sebacic acid diesters such as dioctyl sebacate, etc.; azelaic acid diesters such as dioctyl azelate, etc.), tricarboxylic acid esters (e.g., trimellitic acid triesters such as trioctyl trimellitate, etc.), phosphate esters (e.g., triaryl phosphates such as tricresyl phosphate, etc.), epoxidized vegetable oils (e.g., epoxidized soybean oil, epoxidized linseed oil, etc.), and the like. Also, softeners such as process oils are included in plasticizers. The plasticizer can be used singly or in combination of two or more kinds.

[0036] Examples of the fatty acid esters include fatty acid esters of polyhydric alcohols such as trimethylolpropane, sorbitan, sorbitol, glycerin, and polyglycerol; epoxidized fatty acid alkyl esters such as epoxidized fatty acid octyl ester; and ethylene oxide adducts thereof. The fatty acid forming the fatty acid ester may be, for example, a fatty acid having 8 or more (preferably 12 or more, more preferably 14 or more, still more preferably 16 or more) carbon atoms and 24 or less (preferably 22 or less, for example 20 or less) carbon atoms. Non-limiting specific examples of the fatty acid include lauric acid, myristic acid, palmitic acid, oleic acid, stearic acid, isostearic acid, and the like. Specific examples of the fatty acid ester include trimethylolpropane fatty acid esters such as trimethylolpropane triisostearate and trimethylolpropane trioleate; sorbitan fatty acid esters such as sorbitan monolaurate, sorbitan monostearate, sorbitan tristearate, sorbitan monooleate, and sorbitan trioleate; sorbitol fatty acid esters; glycerin fatty acid esters such as glyceryl triisostearate, glyceryl diisostearate, glyceryl monoisostearate, glyceryl monostearate, and glyceryl monooleate; pentaerythritol fatty acid esters; and the like. In some embodiments, isostearic acid esters (for example, trimethylolpropane triisostearate, glyceryl triisostearate, etc.) can be preferably employed.

[0037] As the higher alcohol, an acyclic monohydric alcohol having about 10 to 24 carbon atoms can be used. In some embodiments, a higher alcohol having 14 or more (more preferably 16 or more, for example 18 or more) carbon atoms can be preferably employed. Specific examples of the higher alcohol include cetyl alcohol, cetostearyl alcohol, stearyl alcohol, isostearyl alcohol, hexyl decanol, octyl dodecanol, and the like.

[0038] The above adhesive layer contains, as the above plasticizer, a plasticizer having a HLB (Hydrophile Lipophile Balance) value of 0.5 or more and 3 or less. By using a plasticizer with an HLB within the above range, the flexibility of the adhesive is enhanced to improve the adhesion to the skin, and disadvantages such as the occurrence of glue residue due to excessive decrease in cohesive force and the decrease in fixing performance are suppressed, thereby achieving a good balance between good adhesion and fixability to the skin and good peelability from the skin (for example, suppression of damage such as horny peeling and suppression of glue residue on the skin). A skin patch adhesive sheet can be preferably realized. As the plasticizer having an HLB of 0.5 or more and 3 or less, those having a corresponding HLB can be used from known plasticizers (for example, various plasticizers described above). The plasticizer having an HLB of 0.5 or more and 3 or less can be used alone or in combination of two or more. In some embodiments, a plasticizer having an HLB in the range of 0.5 or more and 3 or less and a plasticizer having an HLB outside the above range may be used in combination. The proportion of the plasticizer having an HLB in the range of 0.5 or more and 3 or less in the total plasticizer is suitably 30% by weight or more, advantageously 50% by weight or more (for example, more than 50% by weight), may be 70% by weight or more, may be 80% by weight or more, 90% by weight or more, or 95% by weight or more, or may be 100% by weight.

[0039] In addition, the HLB in this specification is the Hydrophile-Lipophile Balance by Griffin, which represents the ratio of hydrophilicity to lipophilicity as a numerical value between 0 and 20. The definition of HLB is as described in W.C. Griffin: J. Soc. Cosmetic Chemists, 1, 311 (1949) and in the co-authored book "Surfactant Handbook" by Takashi Takahashi, Yoshirou Namba, Motoki Koike, and Masao Kobayashi, 3rd edition, published by Kogyo Tosho Publishing Co., Ltd. on November 25, 1972, pages 179 - 182, etc. The plasticizer having the above HLB can be selected based on the common general knowledge of those skilled in the art by referring to the above references as necessary. Also, for materials for which the nominal value of HLB is provided by the manufacturer, etc., the plasticizer can be selected based on the value of its HLB.

[0040] In some embodiments, it is appropriate that the HLB of the plasticizer in the range of 0.5 or more and 3 or less is less than 3.0, and it may be 2.7 or less or 2.6 or less (for example, less than 2.6). From the viewpoint of facilitating the obtaining of higher fixing performance, it may be 2.5 or less, 2.2 or less or 2.0 or less, and may be 1.8 or less (for example, less than 1.8) or 1.7 or less. Further, the HLB of the plasticizer in the range of 0.5 or more and 3 or less may be, for example, 0.8 or more, may be 0.9 or more, and may be 1.0 or more, 1.2 or more or 1.4 or more. By using a plasticizer having such an HLB, an adhesive layer capable of exhibiting good fixing performance while suppressing damage to the skin and a skin patch adhesive sheet provided with the adhesive layer can be preferably realized.

[0041] The content of the plasticizer with an HLB of 0.5 or more and 3 or less in the adhesive layer can be in the range of, for example, 30 parts by weight or more and 200 parts by weight or less with respect to 100 parts by weight of the acrylic block copolymer. In some embodiments, the content of the plasticizer having the above HLB with respect to 100 parts by weight of the acrylic block copolymer may exceed 30 parts by weight (for example, 32 parts by weight or more), may be 40 parts by weight or more, 50 parts by weight or more, or more than 50 parts by weight, may be 55 parts by weight or more, may be 60 parts by weight or more or more than 60 parts by weight, may be 62 parts by weight or more or 65 parts by weight or more, may be 70 parts by weight or more or more than 70 parts by weight, may be 72 parts by weight or more or 75 parts by weight or more, may be 80 parts by weight or more or 85 parts by weight or more. With an increase in the content of the plasticizer, the flexibility of the adhesive (and thus the adhesion to the skin) tends to improve. Also, from the perspective of maintaining appropriate cohesiveness and making it easier to obtain the desired fixing performance, the content of the plasticizer having the above HLB with respect to 100 parts by weight of the acrylic block copolymer is suitably 170 parts by weight or less, and in some embodiments, it is preferably 150 parts by weight or less, may be 120 parts by weight or less, may be 110 parts by weight or less, 100 parts by weight or less, or less than 100 parts by weight. In an embodiment where a plasticizer with an HLB in the range of 0.5 or more and 3 or less and a plasticizer with an HLB outside the above range are used in combination, it is preferable that their total content is within any of the ranges described above.

[0042] (Adhesion - imparting resin) The adhesive layer containing a plasticizer in addition to the above acrylic block copolymer preferably further contains an adhesion - imparting resin. The adhesion - imparting resin can help improve the adhesive force to the skin and the fixing performance. Examples of the adhesion - imparting resin include rosin - based adhesion - imparting resins, rosin - derivative adhesion - imparting resins, petroleum - based adhesion - imparting resins, terpene - based adhesion - imparting resins, phenol - based adhesion - imparting resins, ketone - based adhesion - imparting resins, and the like. These can be used alone or in combination of two or more.

[0043] Examples of the rosin-based tackifying resin include, for example, rosin such as gum rosin, wood rosin, and tall oil rosin, as well as stabilized rosin (e.g., stabilized rosin obtained by disproportionating or hydrogenating the above rosin), polymerized rosin (e.g., a multimer of the above rosin, typically a dimer), modified rosin (e.g., unsaturated acid-modified rosin modified with an unsaturated acid such as maleic acid, fumaric acid, (meth)acrylic acid, etc.).

[0044] Examples of the rosin derivative tackifying resin include esterified products of the above rosin-based tackifying resin (e.g., rosin ester resins such as stabilized rosin ester, polymerized rosin ester, modified rosin ester), phenol-modified products of the above rosin-based tackifying resin (phenol-modified rosin), and esterified products thereof (phenol-modified rosin ester).

[0045] Examples of the petroleum-based tackifying resin include, for example, aliphatic petroleum resins, aromatic petroleum resins, aliphatic / aromatic copolymer-based petroleum resins, alicyclic petroleum resins, and hydrogenated products thereof (e.g., alicyclic saturated hydrocarbon resins).

[0046] Examples of the petroleum-based tackifying resin include aliphatic (C5-based) petroleum resins, aromatic (C9-based) petroleum resins, aliphatic / aromatic copolymer-based (C5 / C9-based) petroleum resins, styrene resins, and hydrogenated products thereof (e.g., alicyclic saturated hydrocarbon resins obtained by hydrogenating aromatic petroleum resins). Other examples of the petroleum-based tackifying resin include coumarone-indene resins and dicyclopentadiene resins. Examples of the styrene resin include those mainly composed of a homopolymer of styrene, those mainly composed of a homopolymer of α-methylstyrene, those mainly composed of a homopolymer of vinyltoluene, and those mainly composed of a copolymer containing two or more of styrene, α-methylstyrene, and vinyltoluene in the monomer composition (e.g., an α-methylstyrene / styrene copolymer resin mainly composed of an α-methylstyrene / styrene copolymer). As the coumarone-indene resin, a resin containing coumarone and indene as monomer components constituting the resin skeleton (main chain) can be used. Examples of monomer components that can be contained in the resin skeleton other than coumarone and indene include styrene, α-methylstyrene, methyl indene, vinyltoluene, and the like.

[0047] Examples of the above terpene-based tackifying resin include α-pinene resin, β-pinene resin, aromatic-modified terpene-based resin, terpene-phenol-based resin, and the like.

[0048] Examples of the above ketone-based tackifying resin include ketone-based resins obtained by condensation of ketones (e.g., aliphatic ketones such as methyl ethyl ketone, methyl isobutyl ketone, acetophenone; alicyclic ketones such as cyclohexanone, methylcyclohexanone, etc.) and formaldehyde; and the like.

[0049] In some embodiments, the tackifying resin preferably contains one or more selected from the group consisting of rosin derivative tackifying resins (such as rosin ester resins) and petroleum-based tackifying resins (such as alicyclic saturated hydrocarbon resins, α-methylstyrene resins, etc.). With such a tackifying resin, it is easier to obtain a skin patch adhesive sheet that more highly and well-balancedly achieves good adhesion and fixability to the skin and good peelability from the skin.

[0050] The softening point of the tackifier resin is not particularly limited and can be, for example, in the range of about 50°C to 180°C. In some embodiments, from the perspective of improving the fixability to the skin and the like, the softening point of the tackifier resin is preferably 60°C or higher, advantageously 70°C or higher, preferably 80°C or higher, and more preferably 90°C or higher. Also, from the perspective of suppressing the melt viscosity and improving the coatability in hot melt coating and the like, the softening point of the tackifier resin is preferably 160°C or lower, more preferably 140°C or lower, and even more preferably 130°C or lower. In some embodiments, from the perspective of improving the adhesive strength and fixing performance while suppressing damage to the skin, the softening point of the tackifier resin is preferably 120°C or lower (for example, less than 120°C), more preferably 115°C or lower, and even more preferably 110°C or lower or 105°C or lower.

[0051] Note that the softening point of the pressure-sensitive resin referred to here is defined as the value measured based on the softening point test method (ring and ball method) specified in JIS K5902 and JIS K2207. Specifically, the sample is melted as quickly as possible at a low temperature, and this is carefully filled into a ring placed on a flat metal plate without forming bubbles. After it has cooled, the raised part including the upper end of the ring is cut off with a slightly heated small knife. Next, a support (ring stand) is placed in a glass container (heating bath) with a diameter of 85 mm or more and a height of 127 mm or more, and glycerin is poured until the depth reaches 90 mm or more. Next, a steel ball (diameter 9.5 mm, weight 3.5 g) and the ring filled with the sample are immersed in glycerin so as not to contact each other, and the temperature of the glycerin is maintained at 20 °C plus or minus 5 °C for 15 minutes. Next, the steel ball is placed on the center of the surface of the sample in the ring, and this is placed at a fixed position above the support. Next, the distance from the upper end of the ring to the glycerin surface is maintained at 50 mm, a thermometer is placed, the center position of the mercury bulb of the thermometer is set at the same height as the center of the ring, and the container is heated. The flame of the Bunsen burner used for heating should hit the middle between the center and the edge of the bottom of the container to make the heating uniform. Note that after heating starts and the temperature reaches 40 °C, the rate of increase in the bath temperature must be 5.0 plus or minus 0.5 °C per minute. The temperature when the sample gradually softens and flows out of the ring and finally contacts the bottom plate is read, and this is taken as the softening point. The softening point is measured simultaneously for two or more samples, and the average value is adopted.

[0052] The content of the tackifier resin in the adhesive layer is not particularly limited and can be set so as to obtain a desired use effect. In some embodiments, the content of the tackifier resin relative to 100 parts by weight of the acrylic block copolymer may be, for example, 25 parts by weight or more, suitably 35 parts by weight or more from the viewpoint of improving the fixing performance, advantageously 45 parts by weight or more, preferably 50 parts by weight or more (more than 50 parts by weight), more preferably 60 parts by weight or more, may be 70 parts by weight or more, and may be 80 parts by weight or more. Also, the content of the tackifier resin relative to 100 parts by weight of the acrylic block copolymer may be, for example, 200 parts by weight or less, suitably 170 parts by weight or less from the viewpoint of improving the flexibility of the adhesive, preferably 150 parts by weight or less, more preferably 120 parts by weight or less, may be 110 parts by weight or less, and may be 100 parts by weight or less (for example, less than 100 parts by weight).

[0053] (Other components) In the above adhesive layer, various additive components known in the field of adhesives, such as antioxidants (for example, phenolic antioxidants such as hindered phenol-based antioxidants, phosphorus-based antioxidants, sulfur-based antioxidants, use of a combination of two or three of these, etc.), anti-aging agents, ultraviolet absorbers, light stabilizers, fillers, antistatic agents, colorants such as pigments and dyes, can be blended as necessary. The types and blending amounts of these additive components that are not essential components may be the same as the normal types and blending amounts in this type of material.

[0054] The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer may be crosslinked as necessary. For crosslinking, known crosslinking agents such as organic metal salts such as zinc stearate and barium stearate, epoxy-based crosslinking agents, isocyanate-based crosslinking agents, oxazoline-based crosslinking agents, aziridine-based crosslinking agents, metal chelate-based crosslinking agents, and melamine-based crosslinking agents can be used. The crosslinking agent can be used alone or in combination of two or more. The amount of the crosslinking agent used is not particularly limited. In one aspect, the amount of the crosslinking agent used relative to 100 parts by weight of the base polymer can be, for example, approximately 0.01 part by weight or more, approximately 0.02 part by weight or more, or approximately 0.05 part by weight or more, and can also be approximately 10 parts by weight or less or approximately 5 parts by weight or less. In some aspects, the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer is preferably substantially non-crosslinked. For example, it is preferably substantially free of components (such as photo-crosslinking agents and curing agents) for introducing a crosslinked structure. The fact that the pressure-sensitive adhesive is substantially non-crosslinked is preferable from the viewpoint of improving adhesion to the skin and is also preferable from the viewpoint of improving coating properties in hot-melt coating.

[0055] In some aspects, in the pressure-sensitive adhesive layer according to some aspects, the proportion of the total weight of the acrylic block copolymer, plasticizer, and, if necessary, the tackifier resin used in the total weight of the organic component contained in the pressure-sensitive adhesive layer is suitably 70% by weight or more, preferably 80% by weight or more, more preferably 90% by weight or more, may be 95% by weight or more, or may be 97% by weight or more. The skin patch adhesive sheet disclosed herein can be preferably implemented in an aspect having a pressure-sensitive adhesive layer with such a composition.

[0056] <Skin patch adhesive sheet> The above adhesive layer can be formed using an acrylic hot-melt adhesive of a corresponding composition. The above hot-melt adhesive is typically applied in the form of a heat-melted solution that substantially does not contain an organic solvent (for example, the content of the organic solvent is 5% by weight or less, preferably 3% by weight or less, more preferably 1% by weight or less). The coating temperature is not particularly limited, but can be, for example, about 100°C to 230°C (preferably about 130°C to 200°C). Note that the adhesive layer is typically formed continuously, but is not limited to such a form, and may be, for example, an adhesive layer formed in a regular or random pattern such as a dot pattern or a stripe pattern. Further, the adhesive sheet for skin attachment disclosed herein may be in a single-sheet form or a roll form. Alternatively, it may be an adhesive sheet processed into various shapes.

[0057] The thickness of the adhesive layer is not particularly limited and can be set according to the purpose. In some embodiments, from the perspective of adhesiveness to the skin and the like, the thickness of the adhesive layer is suitably 5 μm or more, advantageously 10 μm or more, preferably 15 μm or more, more preferably 20 μm or more, and may be 25 μm or more, 30 μm or more, or 35 μm or more. Also, in some embodiments, the thickness of the adhesive layer may be, for example, 300 μm or less, preferably 200 μm or less from the perspective of thinning the adhesive sheet, more preferably 150 μm or less, and may be 120 μm or less, 100 μm or less, 80 μm or less, 60 μm or less, or 50 μm or less.

[0058] When the pressure-sensitive adhesive sheet for skin application disclosed herein has a configuration having a base material, the material of the base material is not particularly limited and can be appropriately selected according to the purpose of use, usage mode, etc. of the pressure-sensitive adhesive sheet. Non-limiting examples of base materials that can be used include polyolefin films mainly composed of polyolefin-based materials such as polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, etc., polyester films mainly composed of polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyvinyl chloride films mainly composed of polyvinyl chloride, polyurethane films mainly composed of polyurethanes such as polyether urethane and polyester urethane, vinyl acetate resin films, polyimide resin films, polyamide resin films, fluororesin films, cellophane, thermoplastic elastomers (TPE) (for example, olefin-based thermoplastic elastomers) or resin films mainly composed of acrylic resins, and other various resin films; resin foams such as foamed polyolefin sheets (PE foam sheets, PP foam sheets, etc.), foamed polyurethane sheets, foamed polychloroprene rubber sheets; rubber sheets such as natural rubber sheets and butyl rubber sheets; various fibrous substances (for example, cotton, jute, manila hemp, pulp, rayon, acetate fiber, polyester fiber, polyvinyl alcohol fiber, polyamide fiber, polyolefin fibers such as polyethylene fiber and polypropylene fiber, etc.) alone or blended, etc., woven fabrics, non-woven fabrics, knitted fabrics, and other fabrics; papers such as Japanese paper, fine paper, kraft paper, crepe paper; metal foils such as aluminum foil and copper foil; etc. A base material having a composite structure (for example, a laminate of two or more of these. Specifically, a laminate of fabrics, a laminate of papers, a laminate of a resin film and a fabric, a laminate of resin films, etc.) may also be used. Here, the resin film is typically a non-porous resin film (for example, a resin film made of a material in which the proportion of air bubbles in the apparent volume is 3% by volume or less, typically 1% by volume or less). The resin film mainly composed of acrylic resin may be a resin film mainly composed of a material generally called acrylic rubber.

[0059] The thickness of the base material is not particularly limited and can be set according to the purpose. In some embodiments, the thickness of the base material can be in the range of approximately 3 μm to 3000 μm (for example, approximately 5 μm to 500 μm). The preferred thickness of the base material can also vary depending on the material of the base material. For example, when using a resin film as the base material, the upper limit of the thickness is preferably 100 μm, more preferably 70 μm, and the lower limit of the thickness is preferably 3 μm, more preferably 5 μm, such as 10 μm, 20 μm or 30 μm. When using fabrics or papers as the base material, the upper limit of the basis weight is preferably 200 g / m 2 、more preferably 150 g / m 2 、for example 100 g / m 2 、70 g / m 2 or 50 g / m 2 and the lower limit of the basis weight is preferably 5 g / m 2 、more preferably 10 g / m 2 、for example 20 g / m 2 。When using a foam as the base material, the upper limit of the thickness is preferably 3000 μm, more preferably 2000 μm, still more preferably 1000 μm, and the lower limit of the thickness is preferably 100 μm, more preferably 200 μm, still more preferably 300 μm.

[0060] From the perspective of preventing stuffiness and itching during the sticking period of the skin-adhesive sheet to the skin surface, pores may be formed in the base material. The pores formed in the base material can be easily obtained by applying known pore-forming techniques such as metal rolls, punching machines, and laser irradiation. In the skin-adhesive sheet provided by this specification, as a method of forming pores in the base material, pores may be formed in the base material itself and then the adhesive layer may be laminated, or after laminating the adhesive layer on the base material, pores may be formed. Note that when pores are formed after laminating the adhesive layer on the base material, pores penetrating the base material and the adhesive layer are formed.

[0061] The base material may be blended with various additives such as fillers (inorganic fillers, organic fillers, etc.), colorants (pigments, dyes, etc.), antistatic agents, anti-aging agents, antioxidants, ultraviolet absorbers, lubricants, etc. as required. The blending ratio of the additives is usually appropriately about 30% by weight or less (for example, 20% by weight or less, typically 10% by weight or less) of the total weight of the base material.

[0062] The method of providing the adhesive layer on the base material is not particularly limited. For example, a method of directly coating the adhesive on the base material to form the adhesive layer (direct method), a method of transferring the adhesive layer formed on an appropriate release surface (for example, the release surface of a release liner) to the base material (transfer method), etc. can be used.

[0063] On the surface of the base material on the side where the adhesive layer is provided, if necessary, for the purpose of enhancing the adhesion and retention with the adhesive layer, etc., for example, physical treatments such as corona discharge treatment, plasma treatment, sand mat processing treatment, ozone exposure treatment, flame exposure treatment, high-voltage shock exposure treatment, ionization radiation treatment, etc.; chemical treatments such as chromic acid treatment; application of a coating agent (primer); etc., surface treatment as an easy adhesion treatment may be performed. On the surface of the base material where the adhesive layer is not provided (that is, the back surface of the adhesive sheet), if necessary, a release treatment (for example, a release treatment with a release treatment agent such as a silicone-based or long-chain alkyl-based one) for enhancing the unwindability from the roll form, or a surface treatment such as an easy adhesion treatment for improving the laminating property may be performed.

[0064] When the adhesive sheet for skin attachment disclosed herein is in the form of a double-sided adhesive sheet with a substrate having a first adhesive layer laminated on the first surface of the substrate and a second adhesive layer laminated on the second surface of the substrate, the double-sided adhesive sheet is used by attaching at least one of the first and second adhesive layers to the skin, and the other adhesive layer may be attached to the skin or to an adherend other than the skin. In the double-sided adhesive sheet with a substrate having such a configuration, the adhesive layer constituting at least the adhesive surface to be attached to the skin may be any of the above-described adhesive layers, and the composition of the adhesive layer constituting the adhesive surface to be attached to an adherend other than the skin is not particularly limited. That is, the adhesive layer constituting the adhesive surface to be attached to an adherend other than the skin may be any of the above-described adhesive layers. For example, in the monomer component constituting the soft block, C 6-12 an adhesive layer based on an acrylic block copolymer having a content of C alkyl acrylate of less than 40% by weight (for example, the monomer component consists of BA), an adhesive layer based on an acrylic random copolymer, an adhesive layer formed of a rubber-based adhesive, a polyester-based adhesive, a urethane-based adhesive, a polyether-based adhesive, a silicone-based adhesive, or the like may be used.

[0065] The adhesive sheet for skin attachment disclosed herein may be in a form in which the adhesive surface is protected by a release liner (in the form of an adhesive sheet with a release liner) in order to prevent contamination of the adhesive surface before use (before attachment to the adherend). The release liner is not particularly limited. For example, a release liner in which the surface of a liner substrate such as a resin film or paper is subjected to a release treatment, a release liner made of a low-adhesion material such as a fluoropolymer (such as polytetrafluoroethylene) or a polyolefin-based resin (such as polyethylene or polypropylene) can be used. For the above-described release treatment, for example, a release treatment agent such as a silicone-based or long-chain alkyl-based release treatment agent can be used.

[0066] The matters disclosed by this specification include the following. [1] An adhesive sheet for skin attachment provided with an adhesive layer, The pressure-sensitive adhesive layer is formed of an acrylic hot-melt pressure-sensitive adhesive containing an acrylic block copolymer and a plasticizer, The acrylic block copolymer has a soft block and a hard block, The monomer component constituting the soft block has a content of an alkyl acrylate having 6 to 12 carbon atoms in the alkyl group of 40% by weight or more, The plasticizer includes a plasticizer having an HLB of 0.5 or more and 3 or less, a pressure-sensitive adhesive sheet for skin attachment. 〔2〕 The pressure-sensitive adhesive layer contains a tackifier resin, the pressure-sensitive adhesive sheet for skin attachment according to the above 〔1〕. 〔3〕 The content of the tackifier resin in the pressure-sensitive adhesive layer is 60 parts by weight or more and 150 parts by weight or less with respect to 100 parts by weight of the acrylic block copolymer, the pressure-sensitive adhesive sheet for skin attachment according to the above 〔2〕. 〔4〕 The tackifier resin includes a tackifier resin having a softening point of 60°C or more and 120°C or less, the pressure-sensitive adhesive sheet for skin attachment according to the above 〔2〕 or 〔3〕. 〔5〕 The content of the plasticizer in the pressure-sensitive adhesive layer is 60 parts by weight or more and 150 parts by weight or less with respect to 100 parts by weight of the acrylic block copolymer, the pressure-sensitive adhesive sheet for skin attachment according to any one of the above 〔1〕 to 〔4〕. 〔6〕 The plasticizer includes a fatty acid ester, the pressure-sensitive adhesive sheet for skin attachment according to any one of the above 〔1〕 to 〔5〕. 〔7〕 The pressure-sensitive adhesive sheet for skin attachment according to any one of the above 〔1〕 to 〔6〕 includes a base material that supports the pressure-sensitive adhesive layer.

Examples

[0067] Hereinafter, several examples related to the present invention will be described, but the present invention is not intended to be limited to the specific examples shown. In the following description, "parts" and "%" are based on weight unless otherwise specified.

[0068] <Materials Used> The contents of the materials shown in Tables 1 and 2 are as follows. (Tackifier Resin) Super Ester A-100: The product name "Super Ester - 100" manufactured by Arakawa Chemical Industries, a rosin ester resin with a softening point of 95 - 105°C. Alcon M-100: Manufactured by Arakawa Chemical Industries, the product name "Alcon M-100", an alicyclic saturated hydrocarbon resin with a softening point of 100°C. Alcon M-90: Manufactured by Arakawa Chemical Industries, the product name "Alcon M-90", an alicyclic saturated hydrocarbon resin with a softening point of 90°C.

[0069] (Plasticizer) Leodol SP-O30V: Manufactured by Kao Corporation, the product name "Leodol SP-O30V", sorbitan trioleate, HLB 1.8. KAK TTI: Manufactured by Kao Alcohol Industries Co., Ltd., the product name "KAK TTI", trimethylolpropane triisostearate, HLB 1.6. TISG: Manufactured by Kao Alcohol Industries Co., Ltd., the product name "TISG", glyceryl triisostearate, HLB 1.6. Lisonol 20SP: Manufactured by Kao Alcohol Industries Co., Ltd., the product name "Lisonol 20SP", octyldodecanol, HLB 2.6. Lisolex PGIS22: Manufactured by Kao Alcohol Industries Co., Ltd., the product name "Lisolex PGIS22", polyglyceryl-2 diisostearate, HLB 4.1. Leodol SP-O10V: Manufactured by Kao Corporation, the product name "Leodol SP-O10V", sorbitan monooleate, HLB 4.3. Leodol TW-O106V: Manufactured by Kao Corporation, the product name "Leodol TW-O106V", polyoxyethylene sorbitan monooleate, HLB 10. Sunsoft Q-182S: Manufactured by Sun Chemical Corporation, the product name "Sunsoft Q-182S", glycerin fatty acid ester, HLB 11. Leodol TW-L106: Manufactured by Kao Corporation, the product name "Leodol TW-L106", polyoxyethylene sorbitan monolaurate, HLB 13.3. Process Oil PW90: Manufactured by Idemitsu Kosan Co., Ltd., the product name "Diana Process Oil PW90", a paraffinic oil, HLB 0.

[0070] <Production of Adhesive Sheet> (Example 1) 100 parts of acrylic block copolymer A, 120 parts of tackifier resin (Super Ester A-100), and 100 parts of plasticizer (Reodol SP-O30V) were mixed in a heat-melted state to prepare the adhesive composition according to this example. As the acrylic block copolymer A, an acrylic block copolymer having a triblock structure of polyMMA block-poly2EHA block-polyMMA block (hereinafter sometimes referred to as "MMA-2EHA-MMA") and synthesized by a known living anionic polymerization method was used. This acrylic block copolymer A has a proportion of MMA in the total monomer components of about 13% and a melt flow rate (MFR) at 230 °C of 0.5 g / 10 min. The above adhesive composition was hot-melt coated on the release-treated surface of a polyethylene terephthalate (PET) film having a release treatment on one side to form an adhesive layer with a thickness of 40 μm. This adhesive layer was transferred to one side of a non-woven fabric (non-woven fabric manufactured by Sanwa Shokai Co., Ltd., product name "D503", thickness 75 μm, basis weight 30 g / m 2 , fiber types: pulp, polyethylene fiber, polypropylene fiber) to produce the adhesive sheet according to this example.

[0071] (Examples 2, 4) Adhesive compositions according to each example were prepared in the same manner as in Example 1 except that the types and amounts of the tackifier resin and the plasticizer were as shown in Table 1. Adhesive sheets according to each example were produced in the same manner as in Example 1 except that this adhesive composition was used.

[0072] (Example 3) 100 parts of an acrylic block copolymer B, 90 parts of a tackifier resin (Alcon M-90), and 90 parts of a plasticizer (TISG) were mixed in a heat-melted state to prepare the pressure-sensitive adhesive composition according to this example. As the acrylic block copolymer B, an acrylic block copolymer having a triblock structure of MMA-2EHA-MMA and synthesized by a known living anionic polymerization method was used. This acrylic block copolymer B has a relatively high molecular weight compared to the acrylic block copolymer A, the proportion of MMA in the total monomer components is about 6%, and the MFR at 190 °C is 0.9 g / 10 min. A pressure-sensitive adhesive sheet according to this example was produced in the same manner as in Example 1 except that this pressure-sensitive adhesive composition was used.

[0073] (Example 5) A pressure-sensitive adhesive composition according to this example was prepared in the same manner as in Example 4 except that an acrylic block copolymer C was used instead of the acrylic block copolymer A. As the acrylic block copolymer C, an acrylic block copolymer having a triblock structure of polyMMA block-poly2EHA / BA block-polyMMA block (hereinafter, may be referred to as "MMA-2EHA / BA-MMA") and synthesized by a known living anionic polymerization method was used. In this acrylic block copolymer C, the weight ratio of 2EHA to BA in the poly2EHA / BA block (that is, the copolymerization ratio based on weight) is 50 / 50, and the proportion of MMA in the total monomer components is about 18%. A pressure-sensitive adhesive sheet according to this example was produced in the same manner as in Example 1 except that this pressure-sensitive adhesive composition was used.

[0074] (Comparative Example 1) A pressure-sensitive adhesive composition according to this example was prepared in the same manner as in Example 1 except that an acrylic block copolymer D was used instead of the acrylic block copolymer A. As the acrylic block copolymer D, a product named "LA-3710" (an acrylic block copolymer having a triblock structure of MMA-BA-MMA) manufactured by Kuraray Co., Ltd. was used. A pressure-sensitive adhesive sheet according to this example was produced in the same manner as in Example 1 except that this pressure-sensitive adhesive composition was used.

[0075] (Comparative Examples 2 to 4) An adhesive composition according to each example was prepared in the same manner as in Example 1, except that the types and amounts of the acrylic block copolymer, tackifier resin, and plasticizer were as shown in Table 1. An adhesive sheet according to each example was produced in the same manner as in Example 1, except that this adhesive composition was used.

[0076] (Examples 6 and 7, Comparative Examples 5 to 10) An adhesive composition according to each example was prepared in the same manner as in Example 1, except that the types and amounts of the acrylic block copolymer, tackifier resin, and plasticizer were as shown in Table 2. An adhesive sheet according to each example was produced in the same manner as in Example 1, except that this adhesive composition was used.

[0077] (Evaluation) The following evaluations were performed on the inner forearm of a total of 7 subjects (age: 20s to 50s) consisting of 6 males and 1 female as adherends. Each evaluation was performed 3 times for each person (i.e., N = 3), and the arithmetic mean value of the measured values of 7 persons × 3 times was displayed in the corresponding columns of Tables 1 and 2. In addition, in Table 2, the data of Examples 3 and 4 are transcribed to make it easier to see the relationship between the HLB of the plasticizer and the evaluation results.

[0078] (Adhesion to skin) The adhesive sheet according to each example was cut into a strip shape with a width of 25 mm and a length of 50 mm to prepare a measurement sample. The subject's forearm was held with the inner side facing upward, and the sample was hand-pressed onto the skin on the inner side of the forearm. Then, a jig attached to a push-pull gauge was used to grasp one end of the sample in the longitudinal direction, and the push-pull gauge was pulled up so that the peeling angle of the sample with respect to the skin was about 90 degrees. The time from when the sample was pressed onto the skin until the start of pulling up the push-pull gauge was within 5 minutes, and the pulling-up speed of the push-pull gauge was about 10 mm / min. The peak value observed until the entire sample was peeled off from the skin was recorded as the skin-adhesive force [N / 25 mm]. In this experiment, it is appropriate that the skin-adhesive force is 0.30 N / 25 mm or more, preferably 0.40 N / 25 mm or more (for example, 0.50 N / 25 mm or more), and more preferably 0.60 N / 25 mm or more.

[0079] (Skin-fixed load peeling) The adhesive sheet according to each example was cut into a strip shape with a width of 10 mm and a length of 150 mm to prepare a measurement sample. The subject's forearm was held with the inner side facing upward, and the sample was hand-pressed onto the skin on the inner side of the forearm. Then, a 30 g weight was attached to one end of the sample on the wrist side, and the subject's forearm was rotated so that the inner side faced downward, and the time [seconds] until the sample peeled off from the skin (peeling in a direction approximately 90 degrees with respect to the skin) over a length of 100 mm from the one end was measured. The time from when the sample was pressed onto the skin until the start of measurement (until the subject's forearm was rotated so that the inner side faced downward) was within 5 minutes. In this experiment, the result of the skin-fixed load peeling is appropriately 6.0 seconds or more, preferably 10 seconds or more, and more preferably 15 seconds or more (for example, 18 seconds or more, further 20 seconds or more).

[0080] (Keratin peeling rate) The samples used for measuring the skin adhesion (samples peeled off from the inner side of the forearm of the subject) were immersed in a staining solution for 30 minutes to stain the cutin adhering to the adhesive surface of the samples. As the staining solution, an aqueous solution containing 0.05% brilliant green (manufactured by Fuji Film Wako Pure Chemical Corporation) and 0.1% crystal violet (manufactured by Fuji Film Wako Pure Chemical Corporation) in pure water was used. After washing away the staining solution adhering to the samples with water, the adhesive surface having the stained cutin was observed with a digital microscope "DSX1000" manufactured by Olympus, and the occupied area ratio [%] of the stained part was calculated using image processing software (app name: PRECiV Core), and the value was taken as the cutin peeling rate [%]. In this experiment, it is appropriate that the cutin peeling rate is less than 30%, and preferably 25% or less.

[0081]

Table 1

[0082]

Table 2

[0083] As shown in Tables 1 and 2, any of the acrylic block copolymers A to C in which the content of 2EHA (C 6-12 alkyl acrylate) in the monomer components constituting the soft block is 40% by weight or more, and a plasticizer having an HLB of 0.5 or more and 3 or less were used in combination in Examples 1 to 7. The adhesive sheets had a skin adhesion of 0.30 N / 25 mm or more, the results of the skin constant load peeling measurement were 6.0 seconds or more, and the cutin peeling rate was less than 30%. They achieved a good balance between good adhesiveness and fixability to the skin and good peelability from the skin.

[0084] On the other hand, as shown in Table 1, in Comparative Examples 1 and 2 where the acrylic block copolymer A used in Examples 1 and 2 was changed to an acrylic block copolymer D (an acrylic block copolymer in which 100% of the monomer components constituting the soft block is BA), the cohesive force of the adhesive was low, and obvious glue residue was generated on the skin in the measurement of the skin adhesion. Therefore, for these comparative examples, the measurement of the skin fixed load peeling and the horny layer peeling rate was not performed. In Comparative Examples 3 and 4 where the amount of the plasticizer used was reduced to prevent the insufficient cohesive force of Comparative Examples 1 and 2, the horny layer peeling rate increased to 30% or more.

[0085] Also, as can be seen from the comparison results between Examples 3, 4, 6, and 7 and Comparative Examples 5 to 9 shown in Table 2, when the HLB of the plasticizer becomes larger than 3, the result of the skin fixed load peeling is clearly reduced, and the skin adhesion generally tends to decrease. In Comparative Example 10 where a plasticizer with an HLB of zero was used, the fixability to the skin was poor, and the sample dropped as soon as the forearm was rotated.

[0086] As described above, specific examples of the present invention have been described in detail, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples exemplified above.

Explanation of Signs

[0087] 1, 2 Adhesive sheet for skin attachment 10 Adhesive layer 10A One surface (adhesive surface) 10B The other surface 20 Substrate 20A First surface 20B Second surface (back surface) 30, 31, 32 Release liner

Claims

1. An adhesive sheet for skin attachment, comprising an adhesive layer, wherein the adhesive layer is formed of an acrylic hot-melt adhesive containing an acrylic block copolymer and a plasticizer, the acrylic block copolymer has a soft block and a hard block, the monomer component constituting the soft block has a content of an alkyl acrylate having 6 to 12 carbon atoms in the alkyl group of 40% by weight or more, the plasticizer contains a plasticizer having an HLB of 0.5 or more and 3 or less, the adhesive sheet for skin attachment.

2. The adhesive sheet for skin attachment according to claim 1, wherein the adhesive layer contains an adhesion-imparting resin.

3. The adhesive sheet for skin attachment according to claim 2, wherein the content of the adhesion-imparting resin in the adhesive layer is 60 parts by weight or more and 150 parts by weight or less with respect to 100 parts by weight of the acrylic block copolymer.

4. The adhesive sheet for skin attachment according to claim 2, wherein the adhesion-imparting resin contains an adhesion-imparting resin having a softening point of 60°C or more and 120°C or less.

5. The adhesive sheet for skin attachment according to any one of claims 1 to 4, wherein the content of the plasticizer in the adhesive layer is 60 parts by weight or more and 150 parts by weight or less with respect to 100 parts by weight of the acrylic block copolymer.

6. The adhesive sheet for skin attachment according to any one of claims 1 to 4, containing a fatty acid ester as the plasticizer.

7. The adhesive sheet for skin attachment according to any one of claims 1 to 4, comprising a base material that supports the adhesive layer.

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