Adhesive and adhesive composition, adhesive sheet, laminate and device with adhesive layer

Abstract

To provide an adhesive that can contribute to saving of a petroleum resource by increasing a ratio of an environment-conscious type material, which has both heat resistance and high dielectric constant, is excellent in corrosion resistance, enables high solid content, and has low viscosity, and an adhesive sheet, a laminate and a device with an adhesive layer which use the same.SOLUTION: An adhesive contains only a resin (A) which is a copolymer of a monomer mixture containing each specific amount of a monomer having 2-octyl (meth)acrylate and a hydroxy group, a carboxy group-containing monomer and other monomers, or an adhesive composition contains the resin (A) and a curing agent (B).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a pressure-sensitive adhesive, a pressure-sensitive adhesive composition, a pressure-sensitive adhesive sheet, a laminate, and a device with a pressure-sensitive adhesive layer. [Background technology]

[0002] Because adhesive sheets having an adhesive layer formed from an adhesive are easy to handle, they are used in a wide range of fields, including label applications and medical applications. Furthermore, adhesive layers are used to bond components together to secure various devices, such as personal computers, mobile phones, and home appliances. Adhesive sheets used to secure devices require a minimum level of adhesive strength to prevent peeling during long-term use, as well as heat resistance to withstand high temperatures. Furthermore, when adhesive sheets are bonded to metal substrates, corrosion of the substrate due to components contained in the adhesive can cause product degradation, so adhesives with corrosion resistance are required.

[0003] On the other hand, for convenient coating during the production of adhesive sheets, adhesives are generally diluted and adjusted to low viscosity before use. Regarding the solvent used for viscosity adjustment, it is desirable to reduce the content as much as possible from the viewpoint of cost and handling. Furthermore, if the solid content of the adjusted solution is low, it tends to be difficult to apply the adhesive thickly and uniformly, so there is a demand for low-viscosity adhesives that can be made with a higher solid content.

[0004] The adhesives described in Patent Documents 1 and 2 are adjusted to a solids content of about 35%. The inventors' investigations revealed that with the adhesives described in Patent Documents 1 and 2, if the solids content was adjusted to 35% or more, the viscosity would become too high, making coating difficult, and therefore it was not possible to increase the solids content. As a result, the high cost of the solvent used and the difficulty of applying a thick layer of adhesive have become major issues.

[0005] Furthermore, as electronic devices become smaller and more highly integrated depending on the product, there is a demand for suppressing the penetration of electromagnetic waves into the interior. For example, the adhesive tape described in Patent Document 3 had insufficient electromagnetic wave shielding performance. In order to improve the electromagnetic wave shielding effect, it is necessary to make the adhesive conductive, and one effective method for improving conductivity is to increase the dielectric constant of the adhesive.

[0006] In addition to the above-mentioned increasing performance requirements, the depletion of petroleum resources and carbon dioxide emissions from the combustion of petroleum-derived products are becoming issues in the industries in which PSA sheets are used. Therefore, attempts are being made to conserve petroleum resources by using bio-derived materials instead of petroleum-derived materials in a variety of industries, starting with the packaging materials field, as well as in the optical and semiconductor fields. One method for increasing the proportion of biologically derived materials in adhesives whose main component is an acrylic polymer is to obtain an acrylic polymer by copolymerizing a monomer mixture containing a (meth)acrylic acid alkyl ester monomer obtained by esterifying a linear alkyl alcohol produced by living organisms with (meth)acrylic acid. Furthermore, there are also tackifying resins made from naturally occurring ingredients, and by selectively using these, it is possible to achieve environmentally friendly products. Increasing the proportion of environmentally friendly materials can contribute to the conservation of petroleum resources, but the current situation is that only limited environmentally friendly materials are used, and there are challenges to putting this into practical use. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-264092 [Patent Document 2] Japanese Patent Application Laid-Open No. 2012-173354 [Patent Document 3] International Publication No. 2015-076174 Summary of the Invention [Problem to be solved by the invention]

[0008] The problem that the present invention aims to solve is to provide an adhesive that can contribute to the conservation of petroleum resources by increasing the proportion of environmentally friendly materials, which has heat resistance, a high dielectric constant, excellent corrosion resistance, and a low viscosity adhesive that is capable of high solidification, as well as an adhesive sheet, laminate, and device with an adhesive layer that use the same. [Means for solving the problem]

[0009] As a result of extensive research, the present inventors have found that the problems of the present invention can be solved by the following aspects, and have thus completed the present invention. That is, the present invention provides a pressure-sensitive adhesive containing only resin (A) which is a copolymer of a monomer mixture, In 100% by mass of the monomer mixture, 2-octyl (meth)acrylate in an amount of 30% by mass or more and less than 99.5% by mass, A monomer having a hydroxy group is 0.1% by mass or more and less than 40% by mass, and 0.1% by mass or more and 55% by mass or less of other monomers other than 2-octyl (meth)acrylate, monomers having a hydroxy group, and monomers having a carboxy group (excluding isobornyl (meth)acrylate and acrylic monomers having an amide group), The adhesive is characterized in that the content of the monomer having a carboxy group in 100% by mass of the monomer mixture is less than 0.5% by mass. [Effects of the Invention]

[0010] The present invention makes it possible to provide an adhesive that can contribute to the conservation of petroleum resources, and that has both heat resistance and a high dielectric constant, and a low viscosity adhesive that allows for high solidification, as well as an adhesive sheet, a laminate, and a device with an adhesive layer that use the same. [Brief explanation of the drawings]

[0011] [Figure 1]1 is a schematic cross-sectional view partially illustrating a laminate of the present invention. [Figure 2] 1 is a schematic cross-sectional view partially illustrating a device with an adhesive layer of the present invention. [Figure 3] 1 is a schematic cross-sectional view partially illustrating a pressure-sensitive adhesive sheet of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] The pressure-sensitive adhesive composition, pressure-sensitive adhesive sheet, and device including a pressure-sensitive adhesive layer according to the present disclosure have the following configurations [1] to

[17] .

[0013] [1] A pressure-sensitive adhesive containing only resin (A) which is a copolymer of a monomer mixture, In 100% by mass of the monomer mixture, 2-octyl (meth)acrylate in an amount of 30% by mass or more and less than 99.5% by mass, A monomer having a hydroxy group is 0.1% by mass or more and less than 40% by mass, and 0.1% by mass or more and 55% by mass or less of other monomers other than 2-octyl (meth)acrylate, monomers having a hydroxy group, and monomers having a carboxy group (excluding isobornyl (meth)acrylate and acrylic monomers having an amide group), And the content of monomers having carboxy groups in 100% by mass of the monomer mixture is 0. A pressure-sensitive adhesive characterized in that the content is less than 5% by mass. [2] The adhesive according to [1], characterized in that the biomass content is 30% or more. [3] A pressure-sensitive adhesive composition comprising the pressure-sensitive adhesive according to [1] and a curing agent (B). [4] The pressure-sensitive adhesive composition according to [3], wherein the curing agent (B) comprises at least one of an isocyanate-based curing agent and an epoxy-based curing agent. [5] The pressure-sensitive adhesive composition according to [3] or [4], further comprising a silane coupling agent (C). [6] The pressure-sensitive adhesive composition according to any one of [3] to [5], which has a gel fraction of 40% or more. [7] A pressure-sensitive adhesive layer obtained from the pressure-sensitive adhesive according to [1] or [2] or the pressure-sensitive adhesive composition according to any one of [3] to [6]. [8] An adhesive sheet comprising the adhesive layer according to [7] and a release film. [9] The pressure-sensitive adhesive sheet according to [8], characterized in that the thickness of the release film is less than 200 μm.

[10] A laminate comprising the pressure-sensitive adhesive layer according to [7] and a substrate.

[11] A device with an adhesive layer, comprising the adhesive layer according to [7] and a device.

[0014] The composition, pressure-sensitive adhesive sheet, laminate and device of the present invention will be described below, but the present invention is not limited thereto. In this specification, the term "(meth)acrylate" includes acrylate and methacrylate, and the term "(meth)acryloxy group" includes acryloxy group and methacryloxy group. The term "monomer" refers to a monomer having an ethylenically unsaturated group. Furthermore, in this specification, a numerical range specified using "to" includes the numerical values ​​before and after "to" as the range of the lower and upper limits. Furthermore, "film" and "sheet" are not distinguished by thickness. In other words, in this specification, "sheet" includes thin film-like products, and "film" in this specification includes thick sheet-like products. Furthermore, the term "adherend" refers to a counterpart to which the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet is attached. Unless otherwise noted, the various components appearing in this specification may be used independently either alone or in combination of two or more.

[0015] <Adhesive> The pressure-sensitive adhesive of the present invention comprises a resin (A).

[0016] <Resin (A)> Resin (A) is a copolymer of a monomer mixture, In 100% by mass of the monomer mixture, 2-octyl (meth)acrylate in an amount of 30% by mass or more and less than 99.5% by mass, A monomer having a hydroxy group is 0.1% by mass or more and less than 40% by mass, and 0.1% by mass or more and 55% by mass or less of other monomers other than 2-octyl (meth)acrylate, monomers having a hydroxy group, and monomers having a carboxy group (excluding isobornyl (meth)acrylate and acrylic monomers having an amide group), The adhesive is characterized in that the content of the monomer having a carboxy group in 100% by mass of the monomer mixture is less than 0.5% by mass.

[0017] [2-Octyl (meth)acrylate] 2-octyl(meth)acrylate is a biomass monomer represented by the following formula (1). (Formula 1) JPEG2025170162000002.jpg54142(R1=H, CH3) The content of 2-octyl (meth)acrylate is 30% by mass or more and less than 99.5% by mass in 100% by mass of the monomer mixture. A content of less than 0% by mass is undesirable because the viscosity of the adhesive increases or the adhesive strength decreases. The lower limit of the 2-octyl (meth)acrylate content is 30% by mass or more to obtain the desired effect, but is preferably 50% by mass or more, and more preferably 70% by mass or more. A higher 2-octyl (meth)acrylate content is preferable because it contributes to saving petroleum resources, but in relation to the content of the hydroxyl group-containing monomer, a content of less than 90% by mass is preferable, and more preferably less than 80% by mass.

[0018] [Monomers with hydroxy groups] The monomer having a hydroxy group is not limited as long as it is a monomer having a hydroxy group in the molecule, and specific examples include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and N-(2-hydroxyethyl)acrylamide. Of these, 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and N-(2-hydroxyethyl)acrylamide are preferred from the viewpoint of adhesive strength and heat resistance.

[0019] The content of the monomer having a hydroxy group is 0.1% by mass or more and less than 40% by mass based on 100% by mass of the monomer mixture. It is preferably 10% by mass or more and less than 40% by mass, and more preferably 20% by mass or more and less than 40% by mass. By ensuring that the content of the monomer having a hydroxy group is 0.1% by mass or more, it is possible to promote curing and prevent whitening under moist heat. Furthermore, by keeping the hydroxy group content below 40% by mass, it is possible to suppress an increase in the viscosity of the solution.

[0020] [Monomers with carboxy groups] The monomer having a carboxy group is not limited as long as it has a carboxy group in the molecule, and specific examples include (meth)acrylic acid, p-carboxybenzyl acrylate, β-carboxyethyl acrylate, maleic acid, monoethyl maleic acid, itaconic acid, citraconic acid, and fumaric acid. Of these, (meth)acrylic acid is preferred from the viewpoint of adhesive strength, and acrylic acid is more preferred.

[0021] The monomer having a carboxy group may or may not be contained, but if it is contained, the content of the monomer having a carboxy group in 100% by mass of the monomer mixture is less than 0.5% by mass in order to prevent corrosion of the adherend by acid. By including a monomer having a carboxy group, the cohesive strength of the adhesive layer is increased, and the adhesive strength and heat resistance are likely to be improved.

[0022] [Other monomers] The other monomer is not particularly limited as long as it is a monomer other than 2-octyl(meth)acrylate, a monomer having a hydroxy group, and a monomer having a carboxy group (however, excluding isobornyl(meth)acrylate and an acrylic monomer having an amide group). Furthermore, as the other monomer, it is preferable to use (meth)acrylate, which is a biomass monomer, in consideration of the environment, and it is more preferable to use (meth)acrylate with a high biomass content.

[0023] Examples of other monomers include nitrile group-containing monomers such as methacrylonitrile and acrylonitrile; acrylate monomers having an alkyl group such as methyl (meth)acrylate, ethyl methacrylate, ter-butyl methacrylate, sec-butyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, isopropyl methacrylate, stearyl (meth)acrylate, and cyclohexyl (meth)acrylate; acrylate monomers having an aromatic ring such as benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, and phenyl (meth)acrylate; monomers having a cyclic amide group such as 4-acryloylmorpholine and vinyl imidazole; and high Tg monomers such as vinyl acetate. In terms of improving cohesive strength and adhesive strength, the high Tg monomer is preferably selected from the group consisting of methyl (meth)acrylate, ethyl methacrylate, isobornyl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, phenyl (meth)acrylate, 4-acryloylmorpholine, and vinyl acetate.

[0024] The content of the other monomer is 0.1% by mass or more and 55% by mass or less, based on 100% by mass of the monomer mixture. By setting the content to 55% by mass or less, it is possible to suppress an increase in viscosity of the adhesive. In terms of suppressing an increase in viscosity, the content is preferably 40% by mass or less, and more preferably 20% by mass or less. By setting the content to 0.1% by mass or more, it is possible to impart performance specific to that monomer. For example, a high Tg monomer can impart cohesive strength, and a biomass monomer can improve the overall biomass content. The content is preferably 1% by mass or more, and more preferably 5% by mass or more.

[0025] The other monomers in the present invention exclude isobornyl (meth)acrylate and acrylic monomers having an amide group, such as acrylamide, N,N-dimethylacrylamide, and diacetoneacrylamide.

[0026] (Production of Resin (A)) The resin (A) can be produced by polymerizing the above-mentioned monomer mixture. The polymerization can be carried out by known polymerization methods such as solution polymerization, bulk polymerization, emulsion polymerization, and suspension polymerization, but solution polymerization is preferred. Solvents used in solution polymerization are preferably, for example, acetone, methyl acetate, ethyl acetate, toluene, xylene, anisole, methyl ethyl ketone, and cyclohexanone. The polymerization temperature is preferably a boiling point reaction at 60 to 120°C. The polymerization time is preferably about 5 to 12 hours.

[0027] The polymerization initiator used for the polymerization is preferably a radical polymerization initiator, and the radical polymerization initiator is generally a peroxide or an azo compound. The peroxides include, for example, di-t-butyl peroxide, dicumyl peroxide, t- Dialkyl peroxides such as butylcumyl peroxide, α,α'-bis(t-butylperoxy-m-isopropyl)benzene, and 2,5-di(t-butylperoxy)hexyne-3; Peroxyesters such as t-butyl peroxybenzoate, t-butyl peroxyacetate, and 2,5-dimethyl-2,5-di(benzoylperoxy)hexane; ketone peroxides such as cyclohexanone peroxide, 3,3,5-trimethylcyclohexanone peroxide, and methylcyclohexanone peroxide; Peroxyketals such as 2,2-bis(4,4-di-t-butylperoxycyclohexyl)propane, 1,1-bis(t-butylperoxy)3,3,5-trimethylcyclohexane, 1,1-bis(t-butylperoxy)cyclohexane, and n-butyl-4,4-bis(t-butylperoxy)valerate; Hydroperoxides such as cumene hydroperoxide, diisopropylbenzene hydroperoxide, and 2,5-dimethylcyclohexane-2,5-dihydroperoxide; diacyl peroxides such as benzoyl peroxide, decanoyl peroxide, lauroyl peroxide, and 2,4-dichlorobenzoyl peroxide; Examples include peroxydicarbonates such as bis(t-butylcyclohexyl) peroxydicarbonate.

[0028] Examples of the azo compound include 2,2'-azobisbutyronitrile such as 2,2'-azobisisobutyronitrile (abbreviation: AIBN) and 2,2'-azobis(2-methylbutyronitrile); 2,2'-azobisvaleronitrile such as 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile) and 2,2'-azobis(2,4-dimethylvaleronitrile); 2,2'-azobispropionitriles such as 2,2'-azobis(2-hydroxymethylpropionitrile); Examples include 1,1'-azobis-1-alkanenitriles such as 1,1'-azobis(cyclohexane-1-carbonitrile).

[0029] The polymerization initiator is preferably used in an amount of 0.01 to 10 parts by mass, more preferably 0.1 to 2 parts by mass, based on 100 parts by mass of the monomer mixture.

[0030] (Weight average molecular weight (Mw)) The weight-average molecular weight of the resin (A) is not particularly limited, but is preferably not more than 2 million, and more preferably not more than 1 million. The weight-average molecular weight is a polystyrene-equivalent value measured by gel permeation chromatography (GPC).

[0031] <Adhesive composition> The pressure-sensitive adhesive composition of the present invention contains a pressure-sensitive adhesive containing a resin (A) and a curing agent (B), and may also contain a silane coupling agent (C) and a tackifying resin (D) as needed.

[0032] <Curing agent (B)> The pressure-sensitive adhesive composition of the present invention contains a curing agent (B), and the curing agent (B) can be used without any particular limitation as long as it provides a crosslinked structure to the pressure-sensitive adhesive composition. The incorporation of a curing agent improves the cohesive strength of the pressure-sensitive adhesive layer, and improves the adhesive strength, heat resistance, and light resistance. The curing agent (B) preferably contains at least one of an isocyanate-based curing agent and an epoxy-based curing agent. By containing at least one of an isocyanate-based curing agent and an epoxy-based curing agent, the cohesive strength of the adhesive can be appropriately increased, and it is preferable in that it is unlikely to adversely affect other physical properties. By containing at least one of an isocyanate-based curing agent and an epoxy-based curing agent, As long as the curing agent satisfies the requirements, known curing agents other than the isocyanate curing agent and the epoxy curing agent may be used in combination.

[0033] The isocyanate curing agent is an isocyanate having two or more isocyanate groups. Examples of the isocyanate include aromatic polyisocyanates, aliphatic polyisocyanates, araliphatic polyisocyanates, alicyclic polyisocyanates, and their biuret forms, nurate forms, and adduct forms, and from the viewpoint of yellowing resistance, aliphatic polyisocyanates, alicyclic polyisocyanates, and their biuret forms, nurate forms, and adduct forms are more preferred.

[0034] Examples of aromatic polyisocyanates include 1,3-phenylene diisocyanate, 4,4'-diphenyl diisocyanate, 1,4-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-toluidine diisocyanate, 2,4,6-triisocyanate toluene, 1,3,5-triisocyanate benzene, dianisidine diisocyanate, 4,4'-diphenyl ether diisocyanate, and 4,4',4"-triphenylmethane triisocyanate.

[0035] Examples of aliphatic polyisocyanates include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (also known as HMDI), pentamethylene diisocyanate, 1,2-propylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene diisocyanate, and 2,4,4-trimethylhexamethylene diisocyanate.

[0036] Examples of the aromatic aliphatic polyisocyanate include ω,ω'-diisocyanate-1,3-dimethylbenzene, ω,ω'-diisocyanate-1,4-dimethylbenzene, ω,ω'-diisocyanate-1,4-diethylbenzene, 1,4-tetramethylxylylene diisocyanate, and 1,3-tetramethylxylylene diisocyanate.

[0037] Examples of alicyclic polyisocyanates include 3-isocyanatemethyl-3,5,5-trimethylcyclohexyl isocyanate (also known as IPDI, isophorone diisocyanate), 1,3-cyclopentane diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 4,4'-methylenebis(cyclohexyl isocyanate), and 1,4-bis(isocyanatemethyl)cyclohexane.

[0038] The biuret compound is a self-condensation product having a biuret bond formed by self-condensation of an isocyanate monomer, such as a biuret compound of hexamethylene diisocyanate.

[0039] The nurate derivative is a trimer of an isocyanate monomer, such as a trimer of hexamethylene diisocyanate, a trimer of isophorone diisocyanate, or a trimer of tolylene diisocyanate.

[0040] The adduct is a bifunctional or higher isocyanate compound obtained by reacting an isocyanate monomer with a bifunctional or higher low-molecular-weight active hydrogen-containing compound. Examples of the adduct include a compound obtained by reacting trimethylolpropane with hexamethylene diisocyanate, a compound obtained by reacting trimethylolpropane with tolylene diisocyanate, a compound obtained by reacting trimethylolpropane with xylylene diisocyanate, a compound obtained by reacting trimethylolpropane with isophorone, and the like. Examples of the compound include a compound obtained by reacting 1,6-hexanediol with hexamethylene diisocyanate, and a compound obtained by reacting 1,6-hexanediol with hexamethylene diisocyanate.

[0041] From the viewpoint of forming a sufficient crosslinked structure, the isocyanate compound is preferably a trifunctional isocyanate compound. The isocyanate compound is more preferably an adduct or nurate, which is a reaction product of an isocyanate monomer and a trifunctional low-molecular-weight active hydrogen-containing compound. The isocyanate compound is preferably a trimethylolpropane adduct of hexamethylene diisocyanate, a nurate of hexamethylene diisocyanate, a trimethylolpropane adduct of tolylene diisocyanate, a nurate of tolylene diisocyanate, a trimethylolpropane adduct of isophorone diisocyanate, or a nurate of isophorone diisocyanate, and more preferably a trimethylolpropane adduct of hexamethylene diisocyanate, a trimethylolpropane adduct of tolylene diisocyanate, or a trimethylolpropane adduct of isophorone diisocyanate.

[0042] Examples of epoxy curing agents include glycerin diglycidyl ether, 1,6-hexanediol diglycidyl ether, N,N,N',N'-tetraglycidyl-m-xylylenediamine, 1,3-bis(N,N'-diglycidylaminomethyl)cyclohexane, and N,N,N',N'-tetraglycidylaminophenylmethane.

[0043] The curing agent (B) is preferably contained in an amount of 0.02 to 4 parts by mass, and more preferably 0.04 to 1 part by mass, per 100 parts by mass of the resin (A). When the content is 0.02 part by mass or more, the cohesive strength is further improved, and when it is 4 parts by mass or less, it becomes easier to achieve both cohesive strength and flexibility, making it easier to obtain sufficient adhesive strength, heat resistance, and light resistance.

[0044] <Silane coupling agent (C)> The pressure-sensitive adhesive composition of the present invention preferably contains a silane coupling agent (C). By including the silane coupling agent (C), adhesive strength, heat resistance, resistance to wet heat whitening, and light resistance can be improved. The silane coupling agent (C) is preferably included in an amount of 0.05 to 0.2 parts by mass per 100 parts by mass of the resin (A). By including the silane coupling agent (C) in an amount of 0.05 to 0.2 parts by mass, it becomes easy to achieve both heat resistance, outgassing resistance, and light resistance.

[0045] Examples of the silane coupling agent (C) include an alkoxysilane compound having a (meth)acryloxy group, an alkoxysilane compound having a vinyl group, an alkoxysilane compound having an amino group, an alkoxysilane compound having a mercapto group, and an alkoxysilane compound having an epoxy group. Specific examples of commercially available products include KBM-403 (3-glycidoxypropyltrimethoxysilane), KBE-403 (3-glycidoxypropyltriethoxysilane), KBM-303 (2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane) (all manufactured by Shin-Etsu Chemical Co., Ltd.), and BYK-325N (polyether-modified polymethylalkylsiloxane) (manufactured by BYK Japan KK).

[0046] <Tackifying resin (D)> The pressure-sensitive adhesive composition of the present invention preferably further contains a tackifier resin (D). As the tackifier resin (D), any of the existing resins can be used, such as aliphatic petroleum resins, aromatic petroleum resins, synthetic hydrocarbon resins, terpene resins, rosin resins (rosin, polymerized rosin, hydrogenated rosin, and their esters with glycerin, pentaerythritol, etc., resin acid dimers, etc.), and acrylic resins. The tackifier resins may be used alone or in combination of two or more.

[0047] Aliphatic petroleum resins include Quinton B170 manufactured by Zeon Corporation, and aromatic petroleum resins. Resins include JXTG's Nisseki Neopolymer L-90, an aliphatic / aromatic petroleum resin. Examples of the rosin derivative include FTR6100 manufactured by Mitsui Chemicals, Inc., and SylvatacRE85 manufactured by Arizona Chemical Company, Inc. and Super Ester A-75 manufactured by Arakawa Chemical Industries, Ltd.

[0048] Examples of synthetic hydrocarbon resins include aliphatic petroleum resins, aromatic petroleum resins, aliphatic / aromatic petroleum resins, hydrogenated petroleum resins, coumarone-indene resins, and phenol resins.

[0049] Examples of terpene resins include α-pinene resins, β-pinene resins, dipentene resins, aromatic modified terpene resins, hydrogenated terpene resins, terpene phenol resins, acid modified terpene resins, styrenated terpene resins, and styrene-aliphatic hydrocarbon copolymer resins.

[0050] Examples of rosin-based resins include rosin ester, polymerized rosin, hydrogenated rosin, disproportionated rosin, maleic acid-modified rosin, fumaric acid-modified rosin, rosin phenolic resin, and natural rosin.

[0051] The content of the tackifier resin (D) is preferably less than 50 parts by mass, and more preferably 40 parts by mass or less, per 100 parts by mass of the resin (A) in the pressure-sensitive adhesive composition. By including the tackifier resin (D), the adhesive strength to the adherend can be improved.

[0052] In addition, the tackifier resin (D) should be made with a biomass content of 80% or more in consideration of the environment. is more preferable. Furthermore, the softening point of the tackifier resin (D) is preferably a higher softening point grade in that it can enhance heat resistance, and is preferably 90°C or higher, more preferably 120°C or higher, and even more preferably 140°C or higher.

[0053] The pressure-sensitive adhesive composition of the present invention may contain various resins, chlorinated polyolefins described below, oils, softeners, dyes, pigments, antioxidants, and ultraviolet absorbers as optional components, as long as the problem can be solved.

[0054] Examples of chlorinated polyolefins include chlorinated polypropylene, acid-modified chlorinated polypropylene, acrylic-modified chlorinated polypropylene, chlorinated polyethylene, and chlorinated ethylene vinyl acetate copolymer. From the viewpoints of good compatibility with acrylic polymers and the like and effective reduction of polarity, chlorinated polypropylene and chlorinated ethylene vinyl acetate copolymer are preferred. Specific examples of commercially available products include Superchlorine 390S (chlorinated polypropylene). , chlorine content 36%), Super Chlon BX (chlorinated EVA, chlorine content 18%) (hereinafter (Product of Nippon Paper Industries Co., Ltd.)

[0055] The pressure-sensitive adhesive composition of the present invention preferably has a gel fraction of 40% or more. However, depending on the application, a gel fraction of 40% or less may also be used. The method for measuring the gel fraction will be described in detail in the Examples.

[0056] The pressure-sensitive adhesive composition of the present invention contains resin (A), which is a copolymer of a monomer mixture containing a specific monomer, and thereby has the effect of suppressing the increase in viscosity that occurs when using an acrylic polymer or the like, and can ensure high adhesive strength to an adherend, thereby significantly reducing the amount of organic solvent used to adjust the viscosity during application compared to conventional methods. In the present invention, when the weight average molecular weight of the resin (A) is 1.9 million to 2.0 million, the solid The viscosity at a solids content of 15% (±1%) is preferably 3000 mPas·s or less, and when the solids content is 700,000 to 900,000, the viscosity at a solids content of 35% (±1%) is preferably 3000 mPas·s or less, and when the solids content is 400,000 to 500,000, the viscosity at a solids content of 50% (±1%) is preferably 3000 mPas·s or less. The method for preparing the solids content and the method for measuring the viscosity are described in detail in the Examples.

[0057] <Adhesive layer> The pressure-sensitive adhesive layer is a layer obtained from the pressure-sensitive adhesive or pressure-sensitive adhesive composition of the present invention. The method for forming the pressure-sensitive adhesive layer is not particularly limited, and may be the same as the coating method described below in the description of the pressure-sensitive adhesive sheet.

[0058] The pressure-sensitive adhesive layer of the present invention preferably has a dielectric constant of 0.5 or more, more preferably 2.0 or more, at 20 GHz. When the dielectric constant at 20 GHz is in this range, the pressure-sensitive adhesive can be made conductive, thereby enhancing the electromagnetic wave shielding effect. The unit of dielectric constant is (F / m). To achieve a dielectric constant within this range, the polarity of the adhesive must be increased, either by using a compound that is inherently highly polar or by reducing the number of carbon atoms contained in the compound. The measurement method will be described in detail in the Examples.

[0059] The adhesive sheet of the present invention preferably has a higher SUS adhesive strength for the purpose of product fixation, etc. Although a lower adhesive strength may be used depending on the product, for versatile use, a peel strength of 3 N / 25 mm or more is preferred. The measurement method will be described in detail in the Examples.

[0060] <Adhesive sheet> The pressure-sensitive adhesive sheet comprises a pressure-sensitive adhesive layer made of the pressure-sensitive adhesive or pressure-sensitive adhesive composition of the present invention and a release film.

[0061] The pressure-sensitive adhesive sheet of the present invention may have a structure in which a release film is formed on one or both sides of the pressure-sensitive adhesive layer.

[0062] <Release film> The release film is not particularly limited, but a transparent plastic substrate can be suitably used. Examples of materials for the transparent plastic substrate include polyesters such as polyethylene terephthalate (PET), acrylic resins such as polymethyl methacrylate (PMMA), and plastic materials such as polycarbonate, triacetyl cellulose, polysulfone, polyarylate, and polycycloolefin. The plastic materials can be used alone or in combination of two or more.

[0063] Among the transparent plastic substrates described above, a transparent plastic substrate having excellent heat resistance, i.e., a transparent plastic substrate that is suppressed or prevented from deforming under severe conditions such as high temperature, high temperature and high humidity, etc. PET films or sheets are particularly suitable as the transparent plastic substrate.

[0064] The thickness of the release film is preferably less than 200 μm. The thickness should be adjusted depending on the handling of the member to be used, but by being less than 200 μm, the material itself is not too stiff, making it easy to wind into a roll and allowing for comfortable use when laminating sheets or the like.

[0065] The pressure-sensitive adhesive sheet of the present invention has excellent heat resistance and a high dielectric constant, and is therefore suitable for use in personal computers, mobile phones, and other electronic devices. It can be used for fixing the exterior or interior of various devices such as home appliances, etc. It can also be used to fix, without particular limitation, different materials from devices, such as polyolefins including polyethylene and polypropylene, resins such as polycarbonate and phenol, metals such as iron, stainless steel (SUS), aluminum and copper, cement, mortar, glass, nonwoven fabric, woven fabric, paper, rubber, foam sheets, etc.

[0066] When applying the adhesive or adhesive composition, the viscosity can be adjusted by adding an appropriate liquid medium. Specific examples include hydrocarbon solvents such as toluene, xylene, hexane, and heptane; ester solvents such as ethyl acetate and butyl acetate; ketone solvents such as acetone and methyl ethyl ketone; halogenated hydrocarbon solvents such as dichloromethane and chloroform; ether solvents such as diethyl ether, methoxytoluene, and dioxane, and other hydrocarbon solvents. However, water and alcohol must be used carefully because they may inhibit the reaction between the resin (A) and the isocyanate curing agent. be.

[0067] The coating method is not particularly limited, and examples thereof include various coating methods using a Mayer bar, applicator, brush, spray, roller, gravure coater, die coater, lip coater, comma coater, knife coater, reverse coater, spin coater, etc. The drying and curing method is also not particularly limited, and examples thereof include hot air drying, infrared rays, reduced pressure methods, and methods using active energy rays, but hot air or steam heating at 60 to 180°C is preferred from the viewpoint of outgassing resistance.

[0068] The thickness of the adhesive layer is preferably 2 to 1000 μm, more preferably 5 to 500 μm. The adhesive layer may be in the form of a single layer or a laminate of two or more layers.

[0069] <Laminate> The laminate of the present invention includes a substrate and a pressure-sensitive adhesive layer. The pressure-sensitive adhesive layer is formed using the pressure-sensitive adhesive sheet of the present invention. Specifically, for example, the release film is peeled off from the pressure-sensitive adhesive sheet of the present invention, and the pressure-sensitive adhesive layer is attached to the substrate to form the laminate.

[0070] <Base material> The substrate refers to the other party to which the adhesive layer of the adhesive sheet having an adhesive layer is attached, and is not limited to a specific one. Examples include polyolefins such as polyethylene and polypropylene, resins such as polycarbonate and phenol, metals such as iron, stainless steel (SUS), aluminum and copper, cement, mortar, glass, nonwoven fabric, woven fabric, paper, rubber, foam sheets, and laminates thereof. The adhesive and adhesive composition of the present invention exhibit excellent adhesive strength to at least one type of adherend. The thickness of the substrate is not particularly limited, and is, for example, preferably less than 500 μm, more preferably 10 to 200 μm, and even more preferably 25 to 150 μm.

[0071] An example of a schematic cross-sectional view partially showing the laminate of the present invention is shown in Figure 1. In Figure 1, 3 is a substrate, 1 is a pressure-sensitive adhesive layer, and 4 and 5 are devices.

[0072] In the laminate shown in FIG. 1, the substrate is attached to the device via an adhesive layer.

[0073] <Production of laminate> The laminate can be produced, for example, by peeling off one release film from a pressure-sensitive adhesive sheet having release films on both sides of the pressure-sensitive adhesive layer and attaching the pressure-sensitive adhesive layer to a substrate. Alternatively, the laminate can be produced by directly forming a pressure-sensitive adhesive layer on a substrate, and then attaching a pressure-sensitive adhesive layer provided on the substrate or another pressure-sensitive adhesive sheet to the pressure-sensitive adhesive layer.

[0074] <Device with adhesive layer> The device with a pressure-sensitive adhesive layer of the present invention is not particularly limited as long as it includes the above-mentioned pressure-sensitive adhesive layer and device. The device with a pressure-sensitive adhesive layer can be produced, for example, using the pressure-sensitive adhesive sheet or laminate of the present invention. That is, it may have a configuration such as pressure-sensitive adhesive layer / device or substrate / pressure-sensitive adhesive layer / device. Alternatively, it may have a configuration such as device 1 / pressure-sensitive adhesive layer / device 2, in which different devices 1 and 2 are bonded together via a pressure-sensitive adhesive layer.

[0075] An example of a schematic cross-sectional view partially illustrating a device with a pressure-sensitive adhesive layer, which is an example of use of the pressure-sensitive adhesive sheet of the present invention, is shown in Figure 2. In Figure 2, 3 is a substrate, 1 is a pressure-sensitive adhesive layer, 4 is device 1, and 5 is device 2. It should be noted that the configuration of the device with a pressure-sensitive adhesive layer is not limited to that shown in Figure 2.

[0076] In the device with a pressure-sensitive adhesive layer shown in Fig. 3, the substrate is attached to a release film via the pressure-sensitive adhesive layer of the present invention (pressure-sensitive adhesive layer). In this way, the device can be commercialized with the release film provided, or can be used in an intermediate process of commercialization.

[0077] There are no particular limitations on the uses of devices with adhesive layers, but examples include all kinds of home appliances such as personal computers, mobile phones, televisions, tablets, and smart watches.

[0078] In light of the recent trend toward environmentally friendly materials, the adhesive and adhesive composition of the present invention can be made partially or entirely from biologically derived materials by using a biomass monomer as the monomer constituting the resin (A) or by using a biomass tackifier. The biomass ratio is preferably 30% or more. The higher the biomass ratio, more preferably 39% or more, and even more preferably 60% or more, the greater the usefulness as an environmentally friendly material. The method for calculating the biomass ratio is described in the Examples. [Example]

[0079] The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to these examples. In the examples, unless otherwise specified, "parts" means "parts by mass" and "%" means "% by mass." The blending amounts in the tables are in parts by mass, and all amounts other than the solvent are calculated as non-volatile content. Blank spaces in the tables indicate that no blending was performed. It is common technical knowledge that the viscosity of a pressure-sensitive adhesive composition increases or decreases depending on the Mw of the resin (A) contained therein, and since the Mw of the resin (A) can be adjusted as appropriate, it is not realistic to confirm the effects of the present invention over the entire Mw range of the resin (A). Therefore, in the examples, resins (A) were produced and evaluated so that the Mw was 400,000 to 500,000, 700,000 to 900,000, or 1,900,000 to 2,000,000. The method for measuring the weight average molecular weight of the resin (A) is as follows.

[0080] <Measurement of weight average molecular weight (Mw) and Mw classification evaluation method> The weight-average molecular weight (Mw) was measured by gel permeation chromatography (GPC). The instrument used was a GPC instrument manufactured by Shimadzu Corporation: an LC-GPC system "Prominence." The columns used were TSKgel α-M manufactured by Tosoh Corporation, with two columns connected in series. N,N-dimethylformamide (DMF) was used as the eluent, and measurements were carried out at 40°C. Mw was determined by conversion using polystyrene with a known Mw as the standard substance. The weight average molecular weight (Mw) of resin (A) is measured, and the evaluation results are as follows: if it is 1.9 million to 2 million, the Mw classification is U; if it is 700,000 to 900,000, the Mw classification is H; and if it is 400,000 to 500,000, the Mw classification is L.

[0081] (Production of Resin (A)) Example 1: Preparation of (A-1) Using a reaction apparatus equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, a thermometer, and a dropping tube, ethyl acetate was added to a reaction vessel as a polymerization solvent, and a monomer mixture of 19.75 parts of 2-octyl acrylate (2-OA), 7 parts of 2-hydroxyethyl acrylate (HEA) and 0.25 parts of 4-hydroxybutyl acrylate (4HBA), 20 parts of methyl acrylate (MA), 3 parts of isobornyl acrylate (IBXA), and 0.04 parts of azobisisobutyronitrile as an initiator was charged into the reaction vessel. A mixture of monomers (19.75 parts 2-octyl acrylate (2-OA), 7 parts 2-hydroxyethyl acrylate (HEA), 0.25 parts 4-hydroxybutyl acrylate (4HBA), 20 parts methyl acrylate (MA), and 3 parts isobornyl acrylate (IBXA), ethyl acetate as the polymerization solvent, and 0.02 parts azobisisobutyronitrile as the initiator, was added dropwise from the dropping tube over approximately 2 hours and polymerized at approximately 80°C for 6 hours under a nitrogen atmosphere. After the reaction was completed, the mixture was cooled and diluted with ethyl acetate to obtain a resin solution. The resulting resin was designated (A-1). The weight-average molecular weight (Mw) of the resulting resin was measured, and the results are shown in Table 1.

[0082] <Examples 2 to 19, Examples 53 to 60, Comparative Production Examples 1 to 5: Production of (A-2 to A-27, A'-1 to A'-5)> Resins (A-2 to A-27, A'-1 to A'-5) were produced in the same manner as in the production of the resin (Example 1), except that the compositions and blending amounts (parts by mass) were changed as shown in Tables 1 to 3. The Mw classification of the obtained resins is shown in Tables 1 and 2. Examples 5, 8, and 19 are reference examples.

[0083] [Table 1]

[0084] [Table 2]

[0085] [Table 3]

[0086] The abbreviations are as follows: Regarding biomass content, only confirmed cases are listed. [2-Octyl (meth)acrylate] 2-OA: 2-octyl acrylate (biomass content 73%) 2-OMA: 2-octyl methacrylate (biomass content 67%) [Monomers with hydroxy groups (OH monomers)] HEA: Hydroxyethyl acrylate 4HBA: 4-hydroxy-normal butyl acrylate HEAA: N-(2-hydroxyethyl)acrylamide [Monomers with carboxy groups (COOH monomers)] AA: acrylic acid [Other monomers] MA: methyl acrylate MMA: Methyl methacrylate BMA: butyl methacrylate 2EHA: 2-ethylhexyl acrylate BA: n-butyl acrylate (biomass content 57%) LA: Lauryl acrylate (biomass content 80%) VAc: vinyl acetate ACMO: acryloylmorpholine BzA: benzyl acrylate [Isobornyl (meth)acrylate] IBXA: Isobornyl acrylate (biomass content 76%)

[0087] Example 20 0.2 parts of "D-165N" (a biuret of hexamethylene diisocyanate, manufactured by Mitsui Chemicals, Inc.) as a curing agent (B) was blended with 100 parts of the resin (A-1) to obtain a pressure-sensitive adhesive composition. The obtained adhesive composition was coated using a comma coater onto a 38 μm thick release liner (SP-PET-O1-BU: manufactured by Mitsui Chemicals Tocello Inc.) as a release sheet so that the thickness after drying would be 25 μm. After drying at 110°C for 3 minutes, a 75 μm thick release liner (SP-PET-O3-B3: manufactured by Mitsui Chemicals Tocello Inc.) as a release sheet was bonded to the adhesive layer and aged in this state at 23°C for 7 days to obtain an adhesive sheet.

[0088] <Examples 21 to 51, Examples 61 to 67, Example 69, Comparative Examples 1 to 5> As shown in Tables 4 and 5, adhesive compositions and adhesive sheets were obtained in the same manner as in Example 20, except that the types and amounts of resin, curing agent (B), silane coupling agent (C), and tackifying resin (D) were changed. Examples 30, 31, 34, 50, and 51 are reference examples.

[0089] <Example 52> An adhesive sheet was obtained in the same manner as in Example 20, except that an adhesive containing only the resin (A-1) obtained in Example 1 was used.

[0090] <Example 68> An adhesive sheet was obtained in the same manner as in Example 20, except that an adhesive containing only the resin (A-24) obtained in Example 57 was used.

[0091] <Gel fraction measurement> The 38 μm release liner was peeled off from the resulting pressure-sensitive adhesive sheet, and the pressure-sensitive adhesive layer was attached to a PET film substrate (Cosmoshine A-4360, 100 μm thick, manufactured by Toyobo Co., Ltd.), which was then cut into a size of 30 mm wide x 100 mm long to prepare a test pressure-sensitive adhesive sheet. The release liner on the other side of the pressure-sensitive adhesive tape was then peeled off to prepare a test specimen, whose weight was measured. The test specimen was immersed in ethyl acetate at 23°C for 24 hours, then removed from the ethyl acetate and dried at 150°C for 30 minutes. The weight of the dried test specimen was measured, and the gel fraction was calculated using the following formula (1). In Table 3, "40%<" means that the gel fraction is greater than 40%. Gel fraction (wt%) = 100 × (W2 − W0) / (W1 − W0) (1) (W0: weight of substrate (PET film), W1: weight of test piece before immersion, W2: weight of test piece after immersion and drying) <Biomass degree calculation> The biomass ratio of the pressure-sensitive adhesive composition was calculated using the following formula (2). , B), tackifier one component (C) system) Biomass degree = {(Aw × Ab) + (Bw × Bb) + (Cw × Cb)} / (Aw + Bw + C w) (2) Aw: weight of monomer A, Bw: weight of monomer B, Cw: weight of tackifier Ab: Biomass ratio of monomer A (%), Bb: Biomass ratio of monomer B (%) Cb: Biomass ratio of monomer C (%) When the biomass degree was specified as a range, the minimum value was used in the calculation.

[0092] The materials used in the examples and comparative examples are listed below. <Curing agent (B)> D-165N: Mitsui Chemicals, hexamethylene diisocyanate biuret Tetrad X: Mitsubishi Gas Chemical Company, multifunctional epoxy resin Aluminum chelate A: Chelate hardener manufactured by Kawaken Fine Chemicals Co., Ltd.

[0093] <Silane coupling agent (C)> KBE-403: (3-glycidoxypropyltriethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd.) <Tackifying resin (D)> A-100: (Super Ester A-100, Arakawa Chemical Industries, Ltd., biomass content 95-100%, softening point 95°C-105°C) YS-T160: (YS Polyster T160, Yasuhara Chemical Co., Ltd., biomass content 70%, softening point 160°C)

[0094] The adhesives and adhesive compositions obtained in Examples 20 to 52, Examples 61 to 69, and Comparative Examples 1 to 5 were evaluated for low viscosity, dielectric constant, heat resistance, and corrosion resistance using the methods described below. The adhesive strength of the adhesive layer to SUS was also measured. The results are shown in Tables 6 and 7.

[0095] <Low viscosity> The adhesives and adhesive compositions of Examples 20 to 52, Examples 61 to 69, and Comparative Examples 1 to 5 were measured for viscosity by the following method and evaluated for low viscosity. If the weight average molecular weight (Mw) of the resin contained was 1.9 million to 2 million (U), the solid content was adjusted to 15% (±1); if the Mw was 700,000 to 900,000 (H), the solid content was adjusted to 35% (±1); if the Mw was 400,000 to 500,000 (L), the solid content was adjusted to 50% (±1), and the viscosity was measured using a Brookfield viscometer (rotor number: M3, rotation speed: 12 rpm). The solid content was adjusted using ethyl acetate. [Evaluation criteria] A: Viscosity less than 3000 mPas·s: Good B: Viscosity 3000 mPa·s or more but less than 4000 mPa·s: Usable C: Viscosity of 4000 mPa·s or more: Not usable

[0096] <Dielectric constant> Samples were prepared by laminating 25 μm PET to both sides of the adhesive layer obtained in the Examples or Comparative Examples, and the dielectric constant (F / m) at a frequency of 20 GHz was measured using the following equipment. Three samples were prepared for each specimen, and the average of the measurements for these three samples was taken as the dielectric constant. After the measurement, the measurement value for the PET alone was subtracted from the value for the three-layer structure of PET-adhesive layer-PET to obtain the measurement value for the adhesive layer itself. Measurement method: Cavity resonator method JIS R1641 IPC-TM650 2.5.5.13 Equipment: AET Corporation, dielectric constant measurement device, cavity resonator TE mode Measurement environment: 23±1℃, 52±1%RH [Evaluation criteria] A: Dielectric constant is 2.7 or more: Excellent B: Dielectric constant is 2.5 or more and less than 2.7: Good C: Dielectric constant is 0.5 or more and less than 2.5: Usable D: Dielectric constant is less than 0.5: Unusable

[0097] <Heat resistance> After preparing a test piece by cutting the obtained adhesive sheet into a size of 25 mm in width and 100 mm in length, the 38 μm release liner of the test piece was peeled off in an atmosphere of 23°C - 50%RH and pasted onto SUS. A 2 kg hand roller was reciprocated once to perform pressure bonding so that the pasting area was 25 mm in width × 40 mm in length. After leaving it to stand for 24 hours in an atmosphere of 23°C - 50%RH, a load of 500 g was applied and it was left to stand for 10 hours in an 80°C environment. After 10 hours, the displacement of the test piece was evaluated using a microscope. A: Displacement of the test piece is less than 0.1 mm: Excellent B: Displacement of the test piece is 0.1 mm or more and less than 0.4 mm: Good C: Displacement of the test piece is 0.4 mm or more and less than 10 mm: Usable D: Displacement of the test piece is 10 mm or more: Unusable

[0098] <Corrosion resistance> After bonding the adhesive sheet onto an aluminum foil, it was left to stand for 48 hours under high temperature and high humidity conditions of 60°C × 90%RH. Then, the adhesive sheet was peeled off from the aluminum foil, and the surface of the aluminum foil was visually confirmed and evaluated according to the following criteria. A: No discoloration was confirmed on the surface of the aluminum foil: Good B: Partial discoloration was confirmed on the surface of the aluminum foil: Usable C: Discoloration was confirmed on the surface of the aluminum foil: Unusable

[0099] <Adhesive force to SUS> The 38 μm release liner was peeled off from the resulting adhesive sheet, and the adhesive layer was bonded to a PET film substrate (Cosmoshine A-4360, 100 μm thick, manufactured by Toyobo Co., Ltd.), which was then cut into a 25 mm wide x 100 mm long piece to prepare a test adhesive sheet. The other 75 μm release liner was peeled off from this test adhesive sheet, and the adhesive layer was attached to a SUS plate in an atmosphere of 23°C and 50% relative humidity (50% RH). The sheet was then roll-pressed in accordance with JIS Z-0237. After 24 hours of pressing, the peel strength (peel angle 180°, peel speed 300 mm / min; unit: N / 25 mm width) was measured using a tensile tester (Tensilon, manufactured by Orientec Co., Ltd.). [Evaluation criteria] A: Peel strength is 3N / 25mm or more. :Can be used B: Peel strength is less than 3N / 25mm. Cannot be used.

[0100] [Table 4]

[0101] [Table 5]

[0102] [Table 6]

[0103] [Table 7] [Explanation of symbols]

[0104] The symbols in Figures 1, 2 and 3 are explained below. 1. Adhesive layer 2 Release film 3 Base material 4. Device 1 5. Device 2

Claims

1. A pressure-sensitive adhesive containing only a resin (A) that is a copolymer of a monomer mixture, In 100% by mass of the monomer mixture, 2-octyl (meth)acrylate in an amount of 30% by mass or more and less than 99.5% by mass; and a monomer having a hydroxy group in an amount of 0.1% by mass or more but less than 40% by mass, and wherein the content of monomers having a carboxy group in 100% by mass of the monomer mixture is less than 0.5% by mass, the content of other alkyl (meth)acrylate monomers other than 2-octyl (meth)acrylate is 55% by mass or less, and the total content of 2-octyl (meth)acrylate and other alkyl (meth)acrylate monomers is 65% by mass or more and 99.2% by mass or less (excluding the case where isobornyl (meth)acrylate is contained in the monomer mixture).

2. The adhesive according to claim 1, wherein the biomass ratio is 30% or more.

3. A pressure-sensitive adhesive composition comprising the pressure-sensitive adhesive according to claim 1 and a curing agent (B).

4. 4. The pressure-sensitive adhesive composition according to claim 3, wherein the curing agent (B) comprises at least one of an isocyanate-based curing agent and an epoxy-based curing agent.

5. The pressure-sensitive adhesive composition according to claim 3, further comprising a silane coupling agent (C).

6. The pressure-sensitive adhesive composition according to claim 3, which has a gel fraction of 40% or more.

7. A pressure-sensitive adhesive layer obtained from the pressure-sensitive adhesive according to claim 1 or 2 or the pressure-sensitive adhesive composition according to any one of claims 3 to 6.

8. A pressure-sensitive adhesive sheet comprising the pressure-sensitive adhesive layer according to claim 7 and a release film.

9. 9. The pressure-sensitive adhesive sheet according to claim 8, wherein the release film has a thickness of less than 200 μm.

10. A laminate comprising the pressure-sensitive adhesive layer according to claim 7 and a substrate.

11. A device with an adhesive layer, comprising the adhesive layer according to claim 7 and a device.

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