Tackifying adhesive sheet, laminated sheet, chemical solution tank, and method for manufacturing chemical solution tank

Abstract

To provide a tackifying adhesive sheet which has excellent tackifying adhesive force to a fluorine resin without pre-treating a fluorine resin such as polytetrafluoroethylene, and excellent sticking workability, a laminated sheet using the tackifying adhesive sheet, and a method for manufacturing a chemical solution tank using the tackifying adhesive sheet.SOLUTION: A tackifying adhesive sheet has a tackifying adhesive layer (Y1) on one surface, and a tackifying adhesive layer (Y2) on the other surface, and has at least one structure selected from the following first structure and the following second structure. First structure: the tackifying adhesive layer (Y1) contains a base polymer (P1) and a tackifying adhesive resin, the base polymer (P1) contains at least one kind selected from the group consisting of a (meth)acrylic copolymer, a styrenic elastomer, and a silicone resin, and the tackifying adhesive layer (Y2) is a hot melt tackifying adhesive layer. Second structure: the tackifying adhesive layer (Y1) has 180° peeling force at 23°C to polytetrafluoroethylene of 5.0 N / 25 mm or more, and the tackifying adhesive layer (Y2) has a probe tackiness value measured under the conditions of 23°C, pressurization force of 98 gf, pressurization speed of 100 mm / sec, pressurization time of 10 seconds, and separating speed 5 mm / sec of 20 N / 5 mmφ or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an adhesive sheet. The present invention also relates to a laminated sheet using the adhesive sheet, and a method for producing a chemical liquid tank using the adhesive sheet. [Background technology]

[0002] Adhesive sheets have been widely used to fix components in electronic devices. Specifically, adhesive sheets are used, for example, to adhere a cover panel for protecting the surface of a portable electronic device to a touch panel module or a display panel module, or to adhere a touch panel module to a display panel module. Adhesive sheets used to fix such electronic device components are required to have not only high adhesiveness but also properties such as heat resistance, thermal conductivity, and impact resistance depending on the environment of the area where they are used (e.g., Patent Documents 1 to 3). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-052050 [Patent Document 2] Japanese Patent Application Laid-Open No. 2015-021067 [Patent Document 3] Japanese Patent Application Laid-Open No. 2015-120876 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, demand for fluororesins has been increasing in various fields due to their excellent heat resistance, chemical resistance, low dielectric properties, and water repellency. For example, ethylene-tetrafluoroethylene copolymer (ETFE) is used in a wide range of fields, such as electrical wire coating and building materials, due to its high mechanical strength and excellent processability.

[0005] In the semiconductor and chemical industries, many chemicals, including acids and alkalis, are used. For the storage and disposal of these chemicals, lining tanks with fluororesin affixed to the tank body are often used to prevent corrosion. Traditionally, adhesives such as chloroprene rubber and epoxy resin have been used to attach fluororesin to the tank body. However, these adhesives cannot achieve sufficient adhesive strength unless the fluororesin is pretreated. To improve adhesive strength, the fluororesin is typically pretreated with naphthalene or glass backing. These pretreatments are not only expensive but also pose issues in terms of quality degradation, safety, and environmental pollution. Therefore, there has been a demand for adhesives that can be used without pretreatment.

[0006] Furthermore, if the adhesive used to bond the fluororesin has too strong an adhesive strength to the can body at room temperature, it may become sticky, resulting in poor workability, and problems may arise such that it is difficult to adjust the position where the fluororesin is bonded on the can body. Therefore, it is desirable to use an adhesive that is less sticky and has excellent workability in bonding, making it easy to adjust the position where the fluororesin is bonded on the can body.

[0007] The present invention provides an adhesive sheet that has excellent adhesive strength to fluororesins such as polytetrafluoroethylene without the need for pretreatment of the fluororesins, and that exhibits excellent lamination workability. The present invention also provides a laminated sheet using the adhesive sheet, and a method for manufacturing a chemical liquid tank using the adhesive sheet. [Means for solving the problem]

[0008] The present disclosure 1 is an adhesive sheet having an adhesive layer (Y1) on one surface and an adhesive layer (Y2) on the other surface, the adhesive sheet having at least one configuration selected from the group consisting of the following first configuration and the following second configuration: First configuration: the adhesive layer (Y1) contains a base polymer (P1) and a tackifier resin, the base polymer (P1) contains at least one selected from the group consisting of a (meth)acrylic copolymer, a styrene-based elastomer, and a silicone resin, and the adhesive layer (Y2) is a hot-melt adhesive layer. Second configuration: the adhesive layer (Y1) has a 180° peel strength against polytetrafluoroethylene at 23°C of 5.0 N / 25 mm or more, and the adhesive layer (Y2) has a probe tack value of 20 N / 5 mmφ or less, measured under conditions of 23°C, a pressure of 98 gf, a pressure rate of 100 mm / sec, a pressure time of 10 seconds, and a peel rate of 5 mm / sec. Disclosure 2 is the adhesive sheet of Disclosure 1 having the above-mentioned first configuration, wherein the adhesive layer (Y1) has a 180° peel strength against polytetrafluoroethylene at 23°C of 2.5 N / 25 mm or more. The present disclosure 3 is the adhesive sheet of the present disclosure 1, having the second configuration, wherein the adhesive layer (Y1) contains a base polymer (P1) and a tackifier resin, and the base polymer (P1) contains at least one selected from the group consisting of a (meth)acrylic copolymer, a styrene-based elastomer, and a silicone resin. The present disclosure 4 is the adhesive sheet of the present disclosure 1, 2 or 3, wherein the softening point of the adhesive layer (Y2) is 40°C or higher. Disclosure 5 is the adhesive sheet of Disclosure 1, 2, 3, or 4, wherein the adhesive sheet has a 180° peel strength from SUS at 23°C of 10 N / 25 mm or more when the adhesive layer (Y2) side is pressure-bonded to SUS by applying a pressure of 0.1 MPa in an environment of 150°C for 10 minutes. The present disclosure 6 is the adhesive sheet according to the present disclosure 1, 2, 3, 4, or 5, wherein the adhesive layer (Y2) contains a base polymer (P2), and the base polymer (P2) comprises at least one selected from the group consisting of a (meth)acrylic copolymer, a styrene-based elastomer, an ethylene-vinyl acetate copolymer, a chloroprene rubber, a nitrile rubber, a polyurethane resin, a polyamide resin, a polyolefin resin, a polyester resin, an epoxy resin, and a silicone resin. The present disclosure 7 is the adhesive sheet of present disclosure 1, 2, 3, 4, 5, or 6, which has the first configuration or the second configuration, and wherein the adhesive layer (Y1) contains a tackifier resin, and the tackifier resin comprises a tackifier resin (T1) having at least one structural unit (A) selected from the group consisting of structural units (A-1), (A-1'), (A-2), (A-2'), (A-3), (A-3'), (A-4), and (A-4') represented by the following formula: The present disclosure 8 is the adhesive sheet of the present disclosure 7, wherein the tackifier resin (T1) further has a structural unit (B) derived from at least one monomer (b) selected from the group consisting of terpene monomers and vinyl monomers. The present disclosure 9 is the adhesive sheet of the present disclosure 1, 2, 3, 4, 5, 6, 7, or 8, which has the first configuration or the second configuration, and wherein the adhesive layer (Y1) contains a tackifier resin, and the tackifier resin comprises at least one tackifier resin (T2) selected from the group consisting of rosin ester resins, terpene resins, terpene phenol resins, and petroleum-based resins. A tenth aspect of the present disclosure is the adhesive sheet according to any one of the first, second, third, fourth, fifth, sixth, seventh, eighth, and ninth aspects of the present disclosure, wherein the adhesive layer (Y1) is not a hot-melt adhesive layer. An eleventh aspect of the present disclosure is the adhesive sheet according to any one of the first, second, third, fourth, fifth, sixth, seventh, eighth, nineteenth, and tenth aspects of the present disclosure, wherein the adhesive layer (Y1) has a thickness of 25 μm or more and 1000 μm or less. The present disclosure 12 is the adhesive sheet of the present disclosure 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or 11, further comprising a substrate layer between the adhesive layer (Y1) and the adhesive layer (Y2). Disclosure 13 is the adhesive sheet of Disclosure 12, wherein the base layer contains at least one selected from the group consisting of polyester resin, polyimide resin, polyether resin, polyolefin resin, polyurethane resin, metal, glass fiber, and carbon fiber. Disclosure 14 is the adhesive sheet of Disclosure 12 or 13, wherein the base material layer is composed of at least one material selected from the group consisting of a nonwoven fabric and a woven fabric. Disclosure 15 is the adhesive sheet of Disclosure 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13 or 14 used for joining a lining sheet to a can body in a chemical tank. A sixteenth aspect of the present disclosure is the adhesive sheet of the fifteenth aspect of the present disclosure, wherein the liquid chemical tank is a liquid chemical tank for semiconductors or a liquid chemical tank for the chemical industry. Disclosure 17 is a laminate sheet comprising a fluororesin-containing sheet on the adhesive layer (Y1) side of the adhesive sheet of Disclosures 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, or 16. Disclosure 18 is a chemical liquid tank having the adhesive sheet of Disclosure 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, or 16 or the laminated sheet of Disclosure 17 attached to the inner surface of a can body. Disclosure 19 is a method for manufacturing a liquid chemical tank, including a step of laminating the laminated sheet of Disclosure 17 to the inside of a can body of the liquid chemical tank. Disclosure 20 is a method for producing a chemical liquid tank according to Disclosure 19, comprising: a step of using an adhesive sheet according to Disclosure 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, or 16, and pressing a sheet containing a fluororesin onto the adhesive layer (Y1) to produce a laminate sheet according to Disclosure 17; and a step of bonding the adhesive layer (Y2) of the laminate sheet to the inside of a can body of the chemical liquid tank. Disclosure 21 is a method for manufacturing a chemical tank according to Disclosure 20, in which, in a step of bonding the adhesive layer (Y2) of the laminated sheet to the inside of a can body of a chemical tank, the laminated sheet is heated to bond the adhesive layer (Y2) to the inside of the can body. Disclosure 22 is a manufacturing method of a chemical tank according to Disclosure 19, 20 or 21, wherein the chemical tank is a chemical tank for semiconductors or a chemical tank for the chemical industry.

[0009] [ka]

[0010] [ka]

[0011] [ka]

[0012] [ka]

[0013] In the formula, R 1 ~R 7 respectively represent a hydrogen atom, an aliphatic hydrocarbon group, an aromatic hydrocarbon group, a polar functional group, an aliphatic hydrocarbon group having a polar functional group, or an aromatic hydrocarbon group having a polar functional group. n and l each represent an integer of 2 or more and 4 or less, and n' and l' each represent an integer of 2 or more and 5 or less. m and k each represent an integer of 1 or more and 4 or less, and m' and k' each represent an integer of 1 or more and 5 or less. Note that * indicates a connecting part. The present invention will be described in detail below.

[0014] The present inventors have investigated a configuration in which an adhesive sheet having different adhesive layers on each of two surfaces is used, one of the adhesive layers contains a specific base polymer, and the other adhesive layer uses a hot-melt adhesive layer as the adhesive layer. Furthermore, the present inventors have investigated a configuration in which an adhesive sheet having different adhesive layers on each of two surfaces is used, and the 180° peel force against polytetrafluoroethylene of one of the adhesive layers is adjusted to a specific value, and the probe tack value at 23°C of the other adhesive layer is adjusted to a specific value. As a result, it was found that in each of the configurations, it is possible to obtain an adhesive sheet that has excellent adhesive strength to fluororesins such as polytetrafluoroethylene without pre-treating the fluororesins, and that is also easy to bond, and this has led to the completion of the present invention. In this specification, "adhesion" and "tacky adhesion" not only refer to a permanent adhesion phenomenon, but also to "adhesion" which is a temporary adhesion phenomenon.

[0015] The adhesive sheet of the present invention has an adhesive layer (Y1) on one surface and an adhesive layer (Y2) on the other surface. The adhesive sheet of the present invention has at least one constitution selected from the group consisting of the following first constitution and the following second constitution. First configuration: the adhesive layer (Y1) contains a base polymer (P1) and a tackifier resin, the base polymer (P1) contains at least one selected from the group consisting of a (meth)acrylic copolymer, a styrene-based elastomer, and a silicone resin, and the adhesive layer (Y2) is a hot-melt adhesive layer. Second configuration: the adhesive layer (Y1) has a 180° peel strength against polytetrafluoroethylene at 23°C of 5.0 N / 25 mm or more, and the adhesive layer (Y2) has a probe tack value of 20 N / 5 mmφ or less, measured under conditions of 23°C, a pressure of 98 gf, a pressure rate of 100 mm / sec, a pressure time of 10 seconds, and a peel rate of 5 mm / sec. Hereinafter, matters common to the first and second configurations will be described without specifying the configuration in question.

[0016] In the first configuration, the adhesive layer (Y1) contains a base polymer (P1). In the first configuration, the base polymer (P1) contains at least one selected from the group consisting of a (meth)acrylic copolymer, a styrene-based elastomer, and a silicone resin. In the second configuration, the adhesive layer (Y1) preferably contains a base polymer (P1). In the second configuration, the base polymer (P1) preferably contains at least one selected from the group consisting of a (meth)acrylic copolymer, a styrene-based elastomer, and a silicone resin. When the base polymer (P1) contains at least one selected from the group consisting of the (meth)acrylic copolymer, the styrene-based elastomer, and the silicone resin, the adhesive layer (Y1) has excellent adhesive strength to fluororesins. In particular, it is preferred that the base polymer (P1) contains at least one selected from the group consisting of a (meth)acrylic copolymer and a styrene-based elastomer, as this allows for a wide range of design options for the adhesive layer (Y1) and enables the adhesive layer (Y1) to exhibit strong adhesive strength. In this specification, the "base polymer" refers to a polymer component that contributes to the development of adhesive properties of the adhesive layer. The tackifier resin described below is not included in the "base polymer".

[0017] The (meth)acrylic copolymer preferably has a structural unit derived from an alkyl (meth)acrylate. The alkyl (meth)acrylate preferably contains an alkyl (meth)acrylate having an alkyl group having from 4 to 12 carbon atoms at the ester terminal. That is, the (meth)acrylic copolymer preferably contains a structural unit derived from an alkyl (meth)acrylate having an alkyl group having from 4 to 12 carbon atoms at the ester terminal. When the (meth)acrylic copolymer contains a structural unit derived from an alkyl (meth)acrylate having an alkyl group having from 4 to 12 carbon atoms at the ester terminal, the glass transition temperature (Tg) of the (meth)acrylic copolymer is further reduced. As a result, the shear storage modulus at 25°C measured at a frequency of 10 Hz in the dynamic viscoelasticity measurement of the adhesive layer (Y1) described below (hereinafter, sometimes simply referred to as the "shear storage modulus at 25°C of the adhesive layer (Y1)") is appropriately reduced, and the flexibility of the adhesive layer (Y1) is further improved, thereby further improving the adhesive strength of the adhesive layer (Y1) to a fluororesin. In this specification, the term "(meth)acrylate" means acrylate or methacrylate.

[0018] Examples of the alkyl(meth)acrylate having an alkyl group having from 4 to 12 carbon atoms at the ester terminal include n-butyl(meth)acrylate, tert-butyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, n-hexyl(meth)acrylate, n-heptyl(meth)acrylate, n-octyl(meth)acrylate, isooctyl(meth)acrylate, n-nonyl(meth)acrylate, isononyl(meth)acrylate, 1-methylheptyl(meth)acrylate, lauryl(meth)acrylate, etc. Among these, the alkyl(meth)acrylate having an alkyl group having from 4 to 12 carbon atoms at the ester terminal preferably includes an alkyl(meth)acrylate having an alkyl group having from 6 to 8 carbon atoms at the ester terminal, since this further improves the adhesive strength (particularly the adhesive strength to fluororesin) of the adhesive sheet obtained. These alkyl(meth)acrylates having an alkyl group with 4 to 12 carbon atoms at the ester terminal may be used alone or in combination of two or more kinds.

[0019] The content of the structural units derived from alkyl(meth)acrylate having an alkyl group with 4 to 12 carbon atoms at the ester terminal in the (meth)acrylic copolymer is preferably 50% by mass or more. When the content of the structural units derived from alkyl(meth)acrylate having an alkyl group with 4 to 12 carbon atoms at the ester terminal is 50% by mass or more, the glass transition temperature (Tg) of the (meth)acrylic copolymer is further reduced, resulting in an appropriate reduction in the shear storage modulus at 25°C of the adhesive layer described below, and further improvement in the flexibility of the adhesive layer (Y1), thereby further improving the adhesive strength to fluororesins. A more preferred lower limit of the content of the structural units derived from alkyl(meth)acrylate having an alkyl group with 4 to 12 carbon atoms at the ester terminal is 90% by mass, and an even more preferred lower limit is 95% by mass. The upper limit of the constituent units derived from alkyl(meth)acrylate having an alkyl group having from 4 to 12 carbon atoms at the ester terminal may be 99.99 mass %, but from the viewpoint of the cohesive strength of the bulk of the pressure-sensitive adhesive layer (Y1), the upper limit is preferably 99 mass %.

[0020] The content of the structural units derived from alkyl(meth)acrylate having an alkyl group with 6 to 8 carbon atoms at the ester terminal in the (meth)acrylic copolymer is preferably 50% by mass or more. When the content of the structural units derived from alkyl(meth)acrylate having an alkyl group with 6 to 8 carbon atoms at the ester terminal is 50% by mass or more, the glass transition temperature (Tg) of the (meth)acrylic copolymer is further reduced, and as a result, the shear storage modulus at 25°C of the adhesive layer described below is appropriately reduced, further improving the flexibility of the adhesive layer (Y1), and therefore further improving the adhesive strength to fluororesin. The content of the structural units derived from alkyl(meth)acrylate having an alkyl group with 6 to 8 carbon atoms at the ester terminal is more preferably 85% by mass, and even more preferably 90% by mass. From the viewpoint of the cohesive strength of the bulk of the pressure-sensitive adhesive layer (Y1), the upper limit of the constituent units derived from alkyl (meth)acrylate having an alkyl group having from 6 to 8 carbon atoms at the ester terminal is preferably 99.5 mass %, more preferably 99 mass %.

[0021] The alkyl (meth)acrylate may contain alkyl (meth)acrylates other than the alkyl (meth)acrylates having an alkyl group having 4 to 12 carbon atoms at the ester terminal. Examples of the other alkyl (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, myristyl (meth)acrylate, cetyl (meth)acrylate, stearyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, esters of 5,7,7-trimethyl-2-(1,3,3-trimethylbutyl)octanol-1 with (meth)acrylic acid, esters of alcohols having a total of 18 carbon atoms and one or two methyl groups in the linear main chain with (meth)acrylic acid, behenyl (meth)acrylate, and arachidyl (meth)acrylate. These other alkyl (meth)acrylates may be used alone or in combination of two or more.

[0022] The (meth)acrylic copolymer preferably further comprises a structural unit derived from a polar functional group-containing monomer. When the (meth)acrylic copolymer comprises a structural unit derived from a polar functional group-containing monomer, the cohesive strength of the bulk of the adhesive layer (Y1) increases, and the adhesive strength of the adhesive sheet to be obtained is further improved.

[0023] The polar functional group is reactive for crosslinking reactions and the like, and is preferably at least one selected from the group consisting of a carboxy group, a hydroxyl group, an amino group, and an epoxy group. Of these, one selected from the group consisting of a carboxy group and a hydroxyl group is more preferred, as this can contribute to improving the adhesive strength of the resulting adhesive sheet. That is, the (meth)acrylic copolymer preferably has at least one structural unit selected from the group consisting of a structural unit derived from a carboxy group-containing (meth)acrylate and a structural unit derived from a hydroxyl group-containing (meth)acrylate. The carboxy group-containing monomer may, for example, be (meth)acrylic acid. Examples of the hydroxyl group-containing monomer include 4-hydroxybutyl(meth)acrylate, 2-hydroxypropyl(meth)acrylate, and 2-hydroxyethyl(meth)acrylate. Examples of the epoxy group-containing monomer include glycidyl (meth)acrylate. These polar functional group-containing monomers may be used alone or in combination of two or more.

[0024] The content of the structural units derived from the carboxyl group-containing monomer in the (meth)acrylic copolymer is preferably 0.01% by mass at the lower limit and 7.0% by mass at the upper limit. When the content of the structural units derived from the carboxyl group-containing monomer is within this range, the cohesive strength of the bulk of the adhesive layer (Y1) can be appropriately adjusted, and the resulting adhesive sheet has superior adhesive strength. The content of the structural units derived from the carboxyl group-containing monomer is more preferably 0.05% by mass at the lower limit and 5.0% by mass at the upper limit, 3.0% by mass at the even more preferred upper limit, and 2.0% by mass at the even more preferred upper limit.

[0025] The content of the structural units derived from the hydroxyl group-containing monomer in the (meth)acrylic copolymer is preferably 0.01% by mass at the lower limit and 3.0% by mass at the upper limit. When the content of the structural units derived from the hydroxyl group-containing monomer is within this range, the cohesive strength of the bulk of the adhesive layer (Y1) can be appropriately adjusted, and the resulting adhesive sheet has superior adhesive strength. The content of the structural units derived from the hydroxyl group-containing monomer is more preferably 0.05% by mass at the lower limit and 2.0% by mass at the upper limit.

[0026] The total content of the structural units derived from the polar functional group-containing monomer in the (meth)acrylic copolymer is preferably 0.01% by mass at the lower limit and 10.0% by mass at the upper limit. When the total content of the structural units derived from the polar functional group-containing monomer is within this range, the cohesive strength of the bulk of the adhesive layer (Y1) can be appropriately adjusted, and the resulting adhesive sheet has superior adhesive strength. The total content of the structural units derived from the polar functional group-containing monomer is more preferably 0.1% by mass at the lower limit and 7.0% by mass at the upper limit, 6.0% by mass at the even more preferred upper limit, and 3.0% by mass at the even more preferred upper limit.

[0027] The (meth)acrylic copolymer may, if necessary, contain a structural unit derived from another copolymerizable polymerizable monomer other than the structural unit derived from the alkyl (meth)acrylate as described above and the structural unit derived from the polar functional group-containing monomer. Examples of the other polymerizable monomers include benzyl (meth)acrylate, 2-butoxyethyl (meth)acrylate, 2-phenoxyethyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, and polypropylene glycol mono(meth)acrylate. Furthermore, examples of the other polymerizable monomers that can be used include various monomers used in general acrylic polymers, such as vinyl carboxylates such as vinyl acetate, and styrene. These other polymerizable monomers may be used alone, or two or more of them may be used in combination.

[0028] The weight-average molecular weight (Mw) of the (meth)acrylic copolymer preferably has a lower limit of 200,000 and an upper limit of 1,600,000. When the weight-average molecular weight (Mw) of the (meth)acrylic copolymer is 200,000 or more, the bulk cohesive strength of the adhesive layer (Y1) is improved, and the adhesive strength of the resulting adhesive sheet is further improved. When the weight-average molecular weight (Mw) of the (meth)acrylic copolymer is 1,600,000 or less, the adhesion of the adhesive layer (Y1) to the fluororesin is further improved. The weight-average molecular weight (Mw) of the (meth)acrylic copolymer more preferably has a lower limit of 300,000, a more preferably upper limit of 1,200,000, an even more preferably lower limit of 500,000, and an even more preferably lower limit of 700,000.

[0029] The ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the (meth)acrylic copolymer (molecular weight distribution, Mw / Mn) preferably has a lower limit of 1.05 and an upper limit of 10.0. When the (meth)acrylic copolymer has a molecular weight distribution (Mw / Mn) of 1.05 or more, the flexibility of the adhesive layer (Y1) is further improved, and the adhesive strength of the adhesive sheet to fluororesin is further improved. When the (meth)acrylic copolymer has a molecular weight distribution (Mw / Mn) of 10.0 or less, the proportion of low molecular weight components is reduced, the cohesive strength of the bulk of the adhesive layer (Y1) is improved, and the adhesive strength of the adhesive sheet to be obtained is further improved. The upper limit of the molecular weight distribution (Mw / Mn) of the (meth)acrylic copolymer is more preferably 8.0, even more preferably 6.0, even more preferably 5.0, particularly preferably 4.5, extremely preferably 4.0, and most preferably 3.5.

[0030] In this specification, the weight-average molecular weight (Mw) and number-average molecular weight (Mn) refer to the weight-average molecular weight and number-average molecular weight measured by gel permeation chromatography (GPC) in terms of standard polystyrene. Specifically, the (meth)acrylic copolymer is diluted 50 times with tetrahydrofuran (THF), and the diluted solution is filtered through a filter (material: polytetrafluoroethylene, pore diameter: 0.2 μm). The resulting filtrate is fed to a gel permeation chromatograph (Waters, "2690 Separations Module," etc.) and subjected to GPC measurement under conditions of a sample flow rate of 1 mL / min and a column temperature of 40°C. The polystyrene-equivalent molecular weight of the (meth)acrylic copolymer is measured, and the weight-average molecular weight (Mw) and number-average molecular weight (Mn) are determined. For example, a GPC KF-802.5L (Showa Denko) or the like can be used as the column, and for example, a differential refractometer or the like can be used as the detector. Furthermore, the molecular weight distribution (Mw / Mn) can be derived from the obtained weight average molecular weight (Mw) and number average molecular weight (Mn).

[0031] The weight average molecular weight (Mw) and the molecular weight distribution (Mw / Mn) of the (meth)acrylic copolymer can be adjusted to fall within the above ranges by, for example, adjusting the composition, polymerization method, polymerization conditions, etc. of the (meth)acrylic copolymer.

[0032] The glass transition temperature (Tg) of the (meth)acrylic copolymer preferably has a lower limit of -70°C and an upper limit of -30°C. When the glass transition temperature of the (meth)acrylic copolymer is within the above range, the shear storage modulus at 25°C of the adhesive layer (Y1) described below can be easily adjusted to an appropriate range, and the adhesive sheet obtained will have superior adhesive strength to fluororesins. The glass transition temperature (Tg) of the (meth)acrylic copolymer is more preferably -60°C and more preferably -40°C. The glass transition temperature can be a value obtained in the first run when measurement is performed using a differential scanning calorimeter (for example, "SII Exstar 6000 / DSC 6220" manufactured by Hitachi High-Tech Science Corporation) under conditions of a nitrogen atmosphere and a temperature rise rate of 10°C / min.

[0033] As a polymerization method for synthesizing the (meth)acrylic copolymer, a conventionally known method can be used in which monomers from which the above-mentioned structural units are derived are subjected to a radical reaction in the presence of a polymerization initiator, and examples thereof include solution polymerization (boiling point polymerization or constant temperature polymerization), emulsion polymerization, suspension polymerization, bulk polymerization, etc. Among these, solution polymerization is preferred because of its simple synthesis.

[0034] When solution polymerization is used as the polymerization method, examples of the reaction solvent include ethyl acetate, toluene, methyl ethyl ketone, methyl sulfoxide, ethanol, acetone, diethyl ether, etc. These reaction solvents may be used alone or in combination of two or more.

[0035] Examples of the polymerization initiator include organic peroxides and azo compounds. Examples of the organic peroxides include 1,1-bis(t-hexylperoxy)-3,3,5-trimethylcyclohexane, t-hexylperoxypivalate, t-butylperoxypivalate, 2,5-dimethyl-2,5-bis(2-ethylhexanoylperoxy)hexane, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, t-butylperoxyisobutyrate, t-butylperoxy-3,5,5-trimethylhexanoate, and t-butylperoxylaurate. Examples of the azo compound include azobisisobutyronitrile and azobiscyclohexanecarbonitrile. These polymerization initiators may be used alone or in combination of two or more.

[0036] The styrene-based elastomer may be a block copolymer having a block derived from the styrene-based monomer and a block derived from the conjugated diene-based monomer, having rubber elasticity at room temperature, and having a hard segment portion and a soft segment portion, where the block derived from the styrene-based monomer is the hard segment portion and the block derived from the conjugated diene-based monomer is the soft segment portion.

[0037] Examples of the styrene-based monomer include styrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, α-methylstyrene, 2,4-dimethylstyrene, 2,4-diisopropylstyrene, 4-t-butylstyrene, 5-t-butyl-2-methylstyrene, vinylethylbenzene, divinylbenzene, trivinylbenzene, divinylnaphthalene, t-butoxystyrene, vinylbenzyldimethylamine, (4-vinylbenzyl)dimethylaminoethyl ether, N,N-dimethylaminoethylstyrene, N,N-dimethylaminomethylstyrene, 2-ethylstyrene, 3-ethylstyrene, 4-ethylstyrene, 2-t-butylstyrene, 3-t-butylstyrene, 4-t-butylstyrene, vinylxylene, vinylnaphthalene, vinylpyridine, diphenylethylene, and tertiary amino group-containing diphenylethylene. Among these, styrene is preferred because of its industrial availability. Examples of the tertiary amino group-containing diphenylethylene include 1-(4-N,N-dimethylaminophenyl)-1-phenylethylene. These styrene-based monomers may be used alone or in combination of two or more.

[0038] Examples of the conjugated diene monomer include isoprene, 1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene, 1,3-heptadiene, 2-phenyl-1,3-butadiene, 3-methyl-1,3-pentadiene, 2-chloro-1,3-butadiene, etc. Among these, 1,3-butadiene and isoprene are preferred because of their high polymerization reactivity and industrial availability. These conjugated diene monomers may be used alone or in combination of two or more.

[0039] Specific examples of the styrene-based elastomer include styrene-isoprene-styrene (SIS) block copolymers, styrene-butadiene-styrene (SBS) block copolymers, styrene-chloroprene-styrene block copolymers, styrene-ethylene-butylene-styrene copolymers (SEBS), and styrene-ethylene-propylene-styrene copolymers (SEPS). Among these, SIS block copolymers and SBS block copolymers are preferred, with SIS block copolymers being more preferred, because the resulting adhesive sheet is likely to exhibit high adhesive strength and is less likely to peel from the adherend even when immersed in an alkaline chemical solution. These styrene-based elastomers may be used alone, or two or more types may be used in combination.

[0040] The styrene-based elastomer may contain a diblock copolymer of a block derived from the styrene-based monomer and a block derived from the conjugated diene-based monomer, in addition to a triblock copolymer of a block derived from the styrene-based monomer and a block derived from the conjugated diene-based monomer. The content ratio of the diblock copolymer in the styrene-based elastomer (hereinafter sometimes referred to as the "diblock ratio") preferably has a lower limit of 50% by mass. When the diblock ratio is 50% by mass or more, the adhesive strength of the adhesive layer (Y1) to the adherend is increased, and the adhesive strength of the obtained adhesive sheet is further improved. In addition, the shear storage modulus at 25°C of the adhesive layer (Y1) described below is appropriately reduced, and the flexibility of the adhesive layer (Y1) is further improved, and therefore the adhesive strength of the adhesive layer (Y1) to fluororesins is further improved. A more preferable lower limit of the diblock ratio is 70% by mass. From the viewpoint of further improving the cohesive strength of the adhesive layer (Y1), the upper limit of the diblock ratio is preferably 90% by mass. The diblock ratio can be calculated from the peak area ratio of each copolymer measured by gel permeation chromatography (GPC).

[0041] The content of the block derived from the styrene-based monomer in the styrene-based elastomer (hereinafter sometimes referred to as "styrene content") preferably has an upper limit of 20 mass%. When the styrene content is 20 mass% or less, the pressure-sensitive adhesive layer (Y1) does not become too hard, the adhesion to the adherend is increased, and the pressure-sensitive adhesive strength of the pressure-sensitive adhesive sheet obtained is further improved. A more preferred upper limit of the styrene content is 16 mass%. From the viewpoint of further improving the cohesive strength of the adhesive layer (Y1), the lower limit of the styrene content is preferably 8 mass %. The styrene content is 1 It can be calculated from the peak area ratio of each block measured by H-NMR.

[0042] The weight-average molecular weight of the styrene elastomer preferably has a lower limit of 50,000 and an upper limit of 600,000. When the weight-average molecular weight of the styrene elastomer is 50,000 or more, the bulk strength of the adhesive layer (Y1) increases, and the adhesive strength of the resulting adhesive sheet is further improved. When the weight-average molecular weight of the styrene elastomer is 600,000 or less, the compatibility of the styrene elastomer with other components is further improved. A more preferred lower limit of the weight-average molecular weight of the styrene elastomer is 100,000, and a more preferred upper limit is 500,000.

[0043] Examples of the silicone resin include silicone compounds having a polydimethylsiloxane structure. Specific examples of the silicone resin include KR-3700 (manufactured by Shin-Etsu Chemical Co., Ltd.).

[0044] The weight-average molecular weight of the silicone resin preferably has a lower limit of 10,000 and an upper limit of 1,000,000. When the weight-average molecular weight of the silicone resin is 10,000 or more, the bulk strength of the adhesive layer (Y1) increases, and the adhesive force of the resulting adhesive sheet is further improved. When the weight-average molecular weight of the silicone resin is 1,000,000 or less, the compatibility of the silicone resin with other components is further improved. The weight-average molecular weight of the silicone resin more preferably has a lower limit of 50,000 and an upper limit of 500,000.

[0045] The preferred lower limit of the content of the base polymer (P1) in the adhesive layer (Y1) is 30 mass%, and the preferred upper limit is 99.5 mass%. When the content of the base polymer (P1) is within the above range, the adhesive strength of the adhesive layer (Y1) to fluororesins is further improved. The more preferred lower limit of the content of the base polymer (P1) is 40 mass%, and the more preferred upper limit is 99 mass%, and the even more preferred lower limit is 50 mass%, and the even more preferred upper limit is 95 mass%.

[0046] In the first configuration, the adhesive layer (Y1) contains a tackifier resin. In the second configuration, the adhesive layer (Y1) preferably contains a tackifier resin. When the adhesive layer (Y1) has the first or second structure and contains the tackifier resin, the tackifier resin preferably contains a tackifier resin (T1) having at least one structural unit (A) selected from the group consisting of the structural unit (A-1), the structural unit (A-1'), the structural unit (A-2), the structural unit (A-2'), the structural unit (A-3), the structural unit (A-3'), the structural unit (A-4), and the structural unit (A-4') represented by the above formula. By containing the tackifier resin (T1), the adhesive layer (Y1) can exhibit higher adhesive strength, particularly high adhesive strength to adherends with low polarity (e.g., fluororesins), and further improve adhesion to the substrate layer described below. In particular, the structural unit (A) is preferably at least one selected from the group consisting of the structural unit (A-1), the structural unit (A-1'), the structural unit (A-2), the structural unit (A-2'), the structural unit (A-3), and the structural unit (A-3'), and more preferably at least one selected from the group consisting of the structural unit (A-1) and the structural unit (A-1'). When the structural unit (A) is at least one selected from the group consisting of the structural unit (A-1) and the structural unit (A-1'), the interaction with the adherend can be further improved, and the tackifier resin can be made of only biological origin, thereby reducing the burden on the environment.

[0047] The tackifier resin (T1) may have the structural unit (A) in a side chain, or in the main chain skeleton or at an end of the main chain skeleton. In particular, the tackifier resin (T1) preferably has the structural unit (A) in the main chain skeleton or at an end of the main chain skeleton, since this allows the resin to have suitable physical properties required as a tackifier resin.

[0048] In the structural unit (A), R 1 ~R 7 respectively represent a hydrogen atom, an aliphatic hydrocarbon group, an aromatic hydrocarbon group, a polar functional group, an aliphatic hydrocarbon group having a polar functional group, or an aromatic hydrocarbon group having a polar functional group. Examples of the aliphatic hydrocarbon group include linear, branched, or cyclic alkyl groups having 1 to 20 carbon atoms. Examples of the aromatic hydrocarbon group include substituted or unsubstituted aryl groups having 1 to 20 carbon atoms. The polar functional group is not particularly limited, and R 1 The polar functional groups other than the hydroxyl group are designated as R 2 The polar functional group other than the carboxyl group is R 3 As OR 4 A polar functional group other than the group represented by R 5 As NR 6 R 7 It is possible to use polar functional groups other than the group represented by the following formula: Specific examples of the polar functional group include an amino group, a carboxy group, a carbonyl group, an alkoxy group, a hydroxyl group, a nitrile group, and a nitro group. Examples of the aliphatic hydrocarbon group having a polar functional group include the above-mentioned aliphatic hydrocarbon group in which one or more hydrogen atoms have been substituted with the above-mentioned polar functional group. Examples of the aromatic hydrocarbon group having a polar functional group include the above-mentioned aromatic hydrocarbon group in which one or more hydrogen atoms have been substituted with the above-mentioned polar functional group.

[0049] In the tackifier resin (T1), multiple R 1 may be the same or different. 1 Similarly, the multiple R groups contained in one structural unit (A-1′) may be the same or different. 1may be the same or different. 1 may be the same or different.

[0050] Similarly, multiple R 2 may be the same or different. 2 Similarly, the multiple R 2 may be the same or different. 2 may be the same or different.

[0051] Similarly, multiple R 3 may be the same or different. 3 Similarly, the multiple R groups contained in one structural unit (A-3′) may be the same or different. 3 may be the same or different. 3 may be the same or different.

[0052] Similarly, multiple R 4 may be the same or different. 4 Similarly, the multiple R groups contained in one structural unit (A-3′) may be the same or different. 4 may be the same or different. 4 may be the same or different.

[0053] Similarly, multiple R 5 may be the same or different. 5 Similarly, the multiple R groups contained in one structural unit (A-4′) may be the same or different. 5 may be the same or different. 5 may be the same or different.

[0054] Similarly, multiple R 6 and R 7 may be the same or different. 6 and R 7 Similarly, the multiple R groups contained in one structural unit (A-4′) may be the same or different. 6 and R 7 may be the same or different. 6 and R 7 may be the same or different.

[0055] In the structural unit (A), n and l are each an integer of 2 or more and 4 or less, and n' and l' are each an integer of 2 or more and 5 or less, and are not particularly limited thereto. From the viewpoint of easy availability of raw materials, n, l, n', and l' are preferably 2 or 3, and n, l, n', and l' are more preferably 3, since this can further increase the adhesive strength of the adhesive layer (Y1).

[0056] In the structural unit (A), m and k are each an integer of 1 or more and 4 or less, and m' and k' are each an integer of 1 or more and 5 or less, and are not particularly limited thereto. From the viewpoint of easy availability of raw materials, m, k, m', and k' are preferably 1, 2, or 3, and more preferably m, k, m', and k' are 1, since this can further increase the adhesive strength of the adhesive layer (Y1).

[0057] Specific examples of the structural unit (A-1) and the structural unit (A-1') include a structural unit derived from dihydroxybenzene or a derivative thereof (when n and n' are 2), and a structural unit derived from trihydroxybenzene or a derivative thereof (when n and n' are 3). These structural units may be used alone, or two or more types may be used in combination. Examples of the dihydroxybenzene or its derivative include resorcinol, pyrocatechol, hydroquinone, dihydroxytoluene, dihydroxyxylene, dihydroxyphenylethylamine hydrochloride, dihydroxybenzoic acid, dihydroxyphenylacetic acid, dihydroxyhydrocinnamic acid, dihydroxyphenylpropionic acid, dihydroxyphenylalanine, dihydroxybenzaldehyde, dihydroxyacetophenone, diacetyldihydroxybenzene, dihydroxyphenyl-2-butanone, dihydroxyphenylmethyl acetate, benzyl dihydroxyphenyl ketone, dihydroxybenzamide, dihydroxymethoxybenzene, dihydroxybenzyl alcohol, dihydroxyphenylethanol, dihydroxyphenyl glycol, dihydroxyphenylacetonitrile, and dihydroxynitrobenzene. Among these, pyrocatechol is preferred because it has little steric hindrance and easily interacts with the adherend. These dihydroxybenzenes or their derivatives may be used alone or in combination of two or more. Examples of the trihydroxybenzene or its derivative include pyrogallol, 1,2,4-trihydroxybenzene, phloroglucinol, trihydroxytoluene, trihydroxydiphenylmethane, 6-hydroxy-L-dopa, gallic acid, methyl gallate, butyl gallate, isobutyl gallate, isoamyl gallate, hexadecyl gallate, stearyl gallate, trihydroxyacetophenone, trihydroxyphenylethanone, trihydroxyphenylbutanone, trihydroxybenzaldehyde, trihydroxybenzamide, and trihydroxynitrobenzene. Among these, pyrogallol is preferred because it has little steric hindrance and easily interacts with the adherend. These trihydroxybenzenes or their derivatives may be used alone or in combination of two or more.

[0058] Specific examples of the structural unit (A-2) and the structural unit (A-2') include structural units derived from benzoic acid, salicylic acid, dihydroxybenzoic acid, gallic acid, 2-methylbenzoic acid, 3-methylbenzoic acid, 4-methylbenzoic acid, 2-ethylbenzoic acid, 3-ethylbenzoic acid, 4-ethylbenzoic acid, 4-tert-butylbenzoic acid, 2-vinylbenzoic acid, 3-vinylbenzoic acid, 4-vinylbenzoic acid, 4,4'-stilbene dicarboxylic acid, and derivatives thereof. Among these, 4-vinylbenzoic acid is preferred because it has little steric hindrance and easily interacts with the adherend. These structural units may be used alone or in combination of two or more.

[0059] Specific examples of the structural unit (A-3) and the structural unit (A-3') include a structural unit derived from a dialkoxybenzene or a derivative thereof (when l and l' are 2), and a structural unit derived from a trialkoxybenzene or a derivative thereof (when l and l' are 3). Examples of the dialkoxybenzene or derivatives thereof include 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, and 1,4-dimethoxybenzene. Examples of the trialkoxybenzene or derivatives thereof include 1,2,3-trimethoxybenzene, 1,2,4-trimethoxybenzene, and 1,3,5-trimethoxybenzene. Among these, 1,2,3-trimethoxybenzene is preferred because it has little steric hindrance and easily interacts with the adherend. These trialkoxybenzenes or derivatives thereof may be used alone or in combination of two or more.

[0060] Specific examples of the structural unit (A-4) and the structural unit (A-4') include structural units derived from aminobenzene or derivatives thereof (when k and k' are 1). Examples of the aminobenzene or derivatives thereof include aniline, methylaniline, ethylaniline, dimethylaniline, and diethylaniline. These aminobenzenes or derivatives thereof may be used alone or in combination of two or more.

[0061] The structural unit (A) may consist solely of petroleum-derived materials, but preferably contains a biologically-derived material. The depletion of petroleum resources and carbon dioxide emissions from the combustion of petroleum-derived products are becoming increasingly problematic. Therefore, attempts have been made to conserve petroleum resources by using biologically-derived materials instead of petroleum-derived materials. It is preferable for the structural unit (A) to contain a biologically-derived material from the perspective of conserving petroleum resources. Furthermore, if the structural unit (A) contains a biologically-derived material, since biologically-derived materials are originally produced by absorbing carbon dioxide from the atmosphere, it is believed that burning it will not increase the total amount of carbon dioxide in the atmosphere, which is also preferable from the perspective of reducing carbon dioxide emissions. Examples of monomers that constitute the structural unit (A) containing a biological material include resorcinol, dihydroxyphenylethylamine hydrochloride, dihydroxyhydrocinnamic acid, dihydroxyphenylalanine, dihydroxybenzaldehyde, dihydroxybenzyl alcohol, pyrogallol, 1,2,4-trihydroxybenzene, phloroglucinol, 6-hydroxy-L-dopa, gallic acid, methyl gallate, butyl gallate, isobutyl gallate, isoamyl gallate, hexadecyl gallate, stearyl gallate, trihydroxyacetophenone, trihydroxybenzaldehyde, trihydroxybenzamide, and trihydroxynitrobenzene.

[0062] The content (by moles) of the structural unit (A) in the tackifier resin (T1) is not particularly limited, but a preferred lower limit is 1 mol% and a preferred upper limit is 60 mol%. When the content of the structural unit (A) is 1 mol% or more, by blending the tackifier resin (T1) in the adhesive layer (Y1), the adhesive strength of the adhesive layer (Y1) can be further increased. When the content of the structural unit (A) is 60 mol% or less, the tackifier resin (T1) can have suitable physical properties required as a tackifier resin. A more preferred lower limit of the content of the structural unit (A) is 5 mol%, a more preferred upper limit is 50 mol%, an even more preferred lower limit is 10 mol%, and an even more preferred upper limit is 30 mol%. Furthermore, the content (by mass) of the structural unit (A) in the tackifier resin (T1) is not particularly limited, but a preferred lower limit is 0.9 mass% and a preferred upper limit is 60 mass%. When the content of the structural unit (A) is 0.9 mass% or more, by blending the tackifier resin (T1) in the adhesive layer (Y1), the adhesive strength of the adhesive layer (Y1) can be further increased. When the content of the structural unit (A) is 60 mass% or less, the tackifier resin (T1) can have suitable physical properties required as a tackifier resin. A more preferred lower limit of the content of the structural unit (A) is 5 mass%, a more preferred upper limit is 50 mass%, an even more preferred lower limit is 10 mass%, and an even more preferred upper limit is 30 mass%.

[0063] The tackifier resin (T1) preferably further comprises a structural unit (B) derived from at least one monomer (b) selected from the group consisting of terpene monomers and vinyl monomers. When the tackifier resin (T1) comprises the structural unit (B), the tackifier resin (T1) can further increase the tackifying and adhesive strength of the adhesive layer (Y1). Furthermore, from the viewpoint of improving the compatibility between the tackifier resin (T1) and the base polymer (P1), a structural unit derived from the terpene monomer is preferred. The structural unit derived from the terpene monomer has an aliphatic hydrocarbon group having an unsaturated double bond, and therefore, when the tackifier resin (T1) has a structural unit derived from a terpene monomer, the compatibility between the tackifier resin (T1) and the base polymer (P1) is improved, and a decrease in the adhesive strength of the adhesive layer (Y1) due to a deterioration in compatibility can be suppressed.

[0064] Examples of the terpene monomer include α-pinene, β-pinene, limonene, dipentene, δ-3-carene, dimethyloctatriene, alloocimene, myrcene, ocimene, linalool, cosmene, etc. Among these, α-pinene, β-pinene, or limonene is preferred because it can further increase the adhesive strength of the adhesive layer (Y1). The vinyl monomer is not particularly limited, but from the viewpoint of improving the compatibility between the tackifier resin (T1) and the base polymer, a vinyl monomer not having a structure containing two or more aromatic rings in one molecule (for example, a naphthalene structure, an anthracene structure, a biphenyl structure, an anthraquinone structure, a benzophenone structure, etc.) is preferred. Examples of the vinyl monomer not having a structure containing two or more aromatic rings in one molecule include ethylene, propylene, butylene, hexene, vinyl acetate, vinyl chloride, styrene, α-methylstyrene, coumarone, indene, vinyltoluene, divinylbenzene, divinyltoluene, and 2-phenyl-2-butene. Among these, styrene is preferred because it can further increase the adhesive strength of the adhesive layer (Y1). These monomers (b) may be used alone or in combination of two or more.

[0065] The structural unit (B) may consist solely of petroleum-derived materials, but preferably contains a biologically-derived material. The depletion of petroleum resources and carbon dioxide emissions from the combustion of petroleum-derived products are becoming increasingly problematic. Therefore, attempts have been made to conserve petroleum resources by using biologically-derived materials instead of petroleum-derived materials. It is preferable for the structural unit (B) to contain a biologically-derived material from the perspective of conserving petroleum resources. Furthermore, if the structural unit (B) contains a biologically-derived material, since biologically-derived materials are originally produced by absorbing carbon dioxide from the atmosphere, it is believed that burning this material will not increase the total amount of carbon dioxide in the atmosphere, which is also preferable from the perspective of reducing carbon dioxide emissions. Examples of the monomer (b) constituting the structural unit (B) containing a biological material include terpene monomers, ethylene, propylene, and hexene.

[0066] The content of the structural unit (B) in the tackifier resin (T1) is preferably 40 mol% or more at the lower limit and 99 mol% or more at the upper limit. When the content of the structural unit (B) is 40 mol% or more, the tackifier resin (T1) can have suitable physical properties required as a tackifier resin. When the content of the structural unit (B) is 99 mol% or less, the content of the structural unit (A) can be sufficiently ensured, thereby further increasing the adhesive strength of the adhesive layer (Y1), and particularly, further increasing the adhesive strength even to adherends with low polarity. A more preferred lower limit of the content of the structural unit (B) is 50 mol% and a more preferred upper limit is 90 mol%.

[0067] The tackifier resin (T1) is not particularly limited as long as it is a compound having the structural unit (A), but is preferably a copolymer having a structure represented by the following formula: In particular, when the structural unit (A) is present in the main chain skeleton or at the end of the main chain skeleton, it is preferably a copolymer having a structure represented by the following formula: The copolymer having such a structure is a copolymer obtainable by a method using cationic polymerization as described below, and can further increase the adhesive strength of the adhesive layer (Y1), and in particular can further increase the adhesive strength even to an adherend with low polarity.

[0068] [ka]

[0069] In the formula, A represents the structural unit (A), B represents the structural unit (B), and s and t each represent an integer of 1 or greater. Note that * represents a linking moiety.

[0070] The tackifier resin (T1) is not particularly limited as long as it is a compound having the structural unit (A), but is preferably a copolymer having the structural unit (A) and the structural unit (B), and may further contain other structural units. When the tackifier resin (T1) is a copolymer having the structural unit (A) and the structural unit (B), the structural units (A) and (B) may be copolymerized randomly, or may be copolymerized with regularity or periodicity, for example, by forming block segments and then bonding to each other.

[0071] The tackifier resin (T1) preferably has an aliphatic hydrocarbon group having an unsaturated double bond. The tackifier resin (T1) may have the aliphatic hydrocarbon group having an unsaturated double bond in the structural unit (A) or the structural unit (B), or in another structural unit. From the viewpoint of ease of synthesis and improving the compatibility between the tackifier resin (T1) and the base polymer (P1), particularly the compatibility between the tackifier resin (T1) and a styrene-based elastomer, it is preferable for the aliphatic hydrocarbon group having an unsaturated double bond to be contained in the structural unit (B) or another structural unit. The structural unit (B) or other structural unit having the aliphatic hydrocarbon group having an unsaturated double bond is not particularly limited, but a structural unit (B) derived from at least one monomer (b) selected from the group consisting of terpene-based monomers and vinyl-based monomers is preferred. That is, the tackifier resin (T1) preferably has the aliphatic hydrocarbon group having an unsaturated double bond in a structural unit (B) derived from at least one monomer (b) selected from the group consisting of a terpene monomer and a vinyl monomer, and particularly preferably in a structural unit derived from a terpene monomer, since this can further increase the tackifying and adhesive strength of the adhesive layer (Y1).

[0072] Furthermore, examples of the other structural units include structural units derived from other phenolic monomers not included in the structural units (A) above, and structural units derived from maleic anhydride. Examples of the other phenolic monomers include phenol, cresol, xylenol, propylphenol, norylphenol, methoxyphenol, bromophenol, bisphenol A, bisphenol F, bisphenol S, dihydroxynaphthalene, etc. These other phenolic monomers may be used alone or in combination of two or more.

[0073] The molecular weight of the tackifier resin (T1) is not particularly limited, but the preferred lower limit of the weight-average molecular weight (Mw) is 400, and the preferred upper limit is 10,000. If the weight-average molecular weight (Mw) of the tackifier resin (T1) is within the above range, the tackifier resin (T1) can have the suitable physical properties required as a tackifier resin. The more preferred lower limit of the weight-average molecular weight (Mw) of the tackifier resin (T1) is 500, the more preferred upper limit is 5,000, the even more preferred lower limit is 550, and the even more preferred upper limit is 3,000. The weight average molecular weight (Mw) can be adjusted to fall within the above range by adjusting, for example, the composition of the tackifier resin (T1), the polymerization method, the polymerization conditions, and the like.

[0074] The Young's modulus of the tackifier resin (T1) at 25°C preferably has a lower limit of 10 MPa. When the Young's modulus of the tackifier resin (T1) at 25°C is 10 MPa or more, the tackifier resin (T1) has an appropriate hardness and can have the suitable physical properties required as a tackifier resin. The lower limit of the Young's modulus of the tackifier resin (T1) at 25°C is more preferably 50 MPa, and even more preferably 70 MPa. In addition, from the viewpoint of preventing the adhesive layer (Y1) from becoming too hard and reducing the adhesive strength, the upper limit of the Young's modulus of the tackifier resin (T1) at 25°C is preferably 10,000 MPa, more preferably 5,000 MPa. The Young's modulus of the tackifier resin (T1) at 25° C. can be measured by conducting a tensile test using a tensile testing device (for example, "Tensilon" manufactured by ORIENTEC) under conditions of a tensile speed of 200 mm / min, a gripping distance of 15 mm, and 25° C. The measurement sample can be prepared, for example, by filling a mold having a size of 10 × 50 mm with the tackifier resin (T1), melting it at a temperature 100° C. higher than the glass transition temperature, and producing a test piece having a thickness of 1 mm.

[0075] The Young's modulus at 25°C of the tackifier resin (T1) can be adjusted to fall within the above range by, for example, adjusting the molecular weight or weight average molecular weight of the tackifier resin (T1), the composition and content of the structural unit (A) and the structural unit (B) in the tackifier resin (T1), etc.

[0076] The glass transition temperature of the tackifier resin (T1) preferably has a lower limit of 0°C and an upper limit of 200°C. If the glass transition temperature of the tackifier resin (T1) is within the above range, the Young's modulus at 25°C of the tackifier resin (T1) can be easily adjusted to be within the above range, and the tackifier resin (T1) can have the suitable physical properties required as a tackifier resin. The lower limit of the glass transition temperature of the tackifier resin (T1) is more preferably 10°C and the upper limit is more preferably 150°C.

[0077] The iodine value of the tackifier resin (T1) is preferably 2 g / 100 g at its lower limit and 180 g / 100 g at its upper limit. When the iodine value of the tackifier resin (T1) is 2 g / 100 g or more, it is possible to prevent a decrease in the adhesive strength of the adhesive layer (Y1) due to a deterioration in the compatibility between the tackifier resin (T1) and the base polymer (P1). When the iodine value of the tackifier resin (T1) is 180 g / 100 g or less, it is possible to further increase the adhesive strength of the adhesive layer (Y1), and in particular, to further increase the adhesive strength even to adherends with low polarity. The iodine value of the tackifier resin (T1) is more preferably 70 g / 100 g at its lower limit and 170 g / 100 g at its upper limit. The iodine value is an index showing the amount of unsaturated double bonds (amount of C=C bonds), and is measured according to the method described in "JIS K 0070:1992".

[0078] The preferred lower limit of the content of biologically derived carbon (carbon atoms) in the total carbon (carbon atoms) of the tackifier resin (T1) is 10%. A biologically derived carbon content of 10% or more is a measure of whether the product is a "bio-based product." A bio-derived carbon content of 10% or more in the tackifier resin (T1) is preferable from the viewpoint of saving petroleum resources and reducing carbon dioxide emissions. A more preferred lower limit of the bio-derived carbon content in the tackifier resin (T1) is 30%, an even more preferred lower limit is 60%, an even more preferred lower limit is 70%, and an especially preferred lower limit is 90%. The upper limit of the bio-derived carbon content in the tackifier resin (T1) is not particularly limited, and may be 100%. Biologically derived carbon contains a certain percentage of the radioactive isotope (C-14), whereas petroleum-derived carbon contains almost no C-14. Therefore, the content of biologically derived carbon in the tackifier resin (T1) can be calculated by measuring the concentration of C-14 contained in the compound. Specifically, this can be measured in accordance with ASTM D6866-22, a standard used in many bioplastic industries.

[0079] The tackifier resin (T1) also includes hydrogenated products of the above-mentioned compounds. The hydrogenated products are compounds in which the carbon-carbon double bonds present in the above-mentioned tackifier resin (T1) are at least partially saturated by hydrogenation. That is, the pressure-sensitive adhesive layer (Y1) may contain a hydrogenated product in which some of the carbon-carbon double bonds in the tackifier resin (T1) are hydrogenated, or a hydrogenated product in which all of the carbon-carbon double bonds in the tackifier resin (T1) are hydrogenated. Even such hydrogenated products are suitably used as the tackifier resin to be blended in the pressure-sensitive adhesive layer (Y1), and can increase the pressure-sensitive adhesive strength of the pressure-sensitive adhesive layer (Y1), particularly, can increase the pressure-sensitive adhesive strength even to adherends with low polarity.

[0080] There are no particular limitations on the method for producing the tackifier resin (T1), but when the structural unit (A) is contained in the main chain skeleton or at the end of the main chain skeleton, the following method is preferred, for example: That is, a method of copolymerizing a monomer (a) constituting the structural unit (A) with at least one monomer (b) selected from the group consisting of terpene monomers and vinyl monomers constituting the structural unit (B) (hereinafter, also referred to as production method [I]).

[0081] The monomer (a) is preferably at least one selected from the group consisting of monomer (a-1), monomer (a-2), monomer (a-3), and monomer (a-4) represented by the following formulas:

[0082] [ka]

[0083] [ka]

[0084] [ka]

[0085] [ka]

[0086] In formulas (a-1) to (a-4), R 1 ~R 7 respectively represent a hydrogen atom, an aliphatic hydrocarbon group, an aromatic hydrocarbon group, a polar functional group, an aliphatic hydrocarbon group having a polar functional group, or an aromatic hydrocarbon group having a polar functional group. n'' represents an integer of 2 or more and 5 or less, preferably 2 or 3, and more preferably 3. m'' represents an integer of 1 or more and 5 or less. l'' represents an integer of 2 or more and 5 or less. k'' represents an integer of 1 or more and 5 or less.

[0087] In the method [I] for producing the tackifier resin (T1), it is preferable to copolymerize the monomer (a) and the monomer (b) by cationic polymerization. By using cationic polymerization, the monomer (a) can be copolymerized with the monomer (b) without protecting functional groups such as phenolic hydroxyl groups, carboxyl groups, alkoxy groups, and amino groups of the monomer (a) in advance by chemical modification, and subsequent deprotection is also unnecessary. Therefore, the monomer (a) can be copolymerized with the monomer (b) in a simpler one-step reaction process, which also leads to a reduction in impurities and an improvement in yield.

[0088] A preferred method for copolymerizing the monomer (a) and the monomer (b) by cationic polymerization is to react the monomer (a) and the monomer (b) in the presence of a Lewis acid. This method is believed to generate cations of the monomer (b), allowing the cationic polymerization of the monomers (b) to proceed, while also allowing the Friedel-Crafts alkylation reaction between the monomers (a) and (b). Repeated reactions of this kind can produce a copolymer having the structural unit (A) derived from the monomer (a) and the structural unit (B) derived from the monomer (b). The Lewis acid is not particularly limited, and any conventionally known Lewis acid can be used, such as aluminum chloride (AlCl), diethylaluminum chloride (EtAlCl), tin(IV) chloride (SnCl), titanium(IV) chloride (TiCl), boron trichloride (BCl), boron trifluoride etherate (BF·EtO), etc. Among these, aluminum chloride (AlCl) is preferred because it can provide a higher yield of copolymer.

[0089] More specifically, for example, when pyrogallol is used as the monomer (a) and α-pinene is used as the monomer (b), and these are reacted in the presence of aluminum chloride (AlCl), which is a Lewis acid, the reaction shown in the following scheme is thought to proceed. That is, cations of α-pinene, the monomer (b), are generated, and cationic polymerization of α-pinene proceeds (upper part of the scheme below), while a Friedel-Crafts alkylation reaction between pyrogallol, the monomer (a), and α-pinene, the monomer (b), proceeds (middle part of the scheme below). By repeating these reactions, a copolymer having structural units derived from pyrogallol and structural units derived from α-pinene can be obtained (lower part of the scheme below). Such a copolymer has structural units derived from pyrogallol in the main chain or at the terminal of the main chain.

[0090] [ka]

[0091] In the formula, s and t each represent an integer of 1 or more, and * represents a linking portion.

[0092] When the structural unit (A) is contained in a side chain, the following method is preferred as a method for producing the tackifier resin (T1): That is, a method of copolymerizing a monomer (a') obtained by further introducing an unsaturated double bond into the monomer (a) constituting the structural unit (A) with at least one monomer (b) selected from the group consisting of terpene monomers and vinyl monomers constituting the structural unit (B) (hereinafter, also referred to as production method [II]).

[0093] Examples of the monomer (a') include 2-vinylbenzoic acid, 3-vinylbenzoic acid, 4-vinylbenzoic acid, and 4,4'-stilbene dicarboxylic acid. Among these, 4-vinylbenzoic acid is preferred because it has little steric hindrance and easily interacts with the adherend. These monomers (a') may be used alone or in combination of two or more.

[0094] In the production method [II] of the tackifier resin (T1), it is preferable to copolymerize the monomer (a') and the monomer (b) by cationic polymerization, as in the production method [I] of the tackifier resin (T1). As a method for copolymerizing the above-mentioned monomer (a') and the above-mentioned monomer (b) by cationic polymerization, a method in which the above-mentioned monomer (a') and the above-mentioned monomer (b) are reacted in the presence of the above-mentioned Lewis acid is preferred. According to this method, cationic polymerization of the unsaturated double bond in the above-mentioned monomer (a') and the unsaturated double bond in the above-mentioned monomer (b) proceeds, and a copolymer having the structural unit (A) derived from the above-mentioned monomer (a') and the structural unit (B) derived from the above-mentioned monomer (b) can be obtained.

[0095] The tackifier resin (T1) can enhance the adhesive strength of the adhesive layer (Y1) even in a smaller amount than conventional tackifier resins. The content of the tackifier resin (T1) relative to 100 parts by mass of the base polymer (P1) preferably has a lower limit of 5 parts by mass and an upper limit of 50 parts by mass. When the content of the tackifier resin (T1) is 5 parts by mass or more, the adhesive strength of the adhesive layer (Y1) can be further enhanced, and in particular, the adhesive strength can be further enhanced even for adherends with low polarity (e.g., fluororesins). When the content of the tackifier resin (T1) is 50 parts by mass or less, a decrease in the adhesive strength due to the adhesive layer (Y1) becoming too hard can be suppressed. The lower limit of the content of the tackifier resin (T1) is more preferably 10 parts by mass, and the upper limit is more preferably 35 parts by mass, even more preferably 30 parts by mass, and even more preferably 20 parts by mass.

[0096] When the adhesive layer (Y1) has the first or second configuration and contains the tackifier resin, the tackifier resin preferably contains at least one tackifier resin (T2) selected from the group consisting of rosin ester resins, terpene resins, terpene phenol resins, and petroleum resins. When the tackifier resin contains the tackifier resin (T2), the adhesive strength of the adhesive layer (Y1) can be further increased. In this specification, the term "terpene resin" refers to a resin having a structural unit derived from a monoterpene and not having a structural unit having an aromatic compound, and the term "terpene phenol resin" refers to a resin having a structural unit derived from a monoterpene and a structural unit derived from a phenol. The structural unit (A-1) and the structural unit (A-1') are not considered to be structural units derived from the phenol.

[0097] The softening temperature of the tackifier resin (T2) preferably has a lower limit of 50°C and an upper limit of 200°C. When the softening temperature of the tackifier resin (T2) is 50°C or higher, it is possible to prevent the pressure-sensitive adhesive layer (Y1) from becoming too soft and thereby reducing its adhesive strength. When the softening temperature of the tackifier resin (T2) is 200°C or lower, it is possible to improve the wettability of the interface of the pressure-sensitive adhesive layer (Y1), thereby preventing interfacial peeling. In addition, the glass transition temperature (Tg) of the (meth)acrylic copolymer is further reduced. As a result, the shear storage modulus at 25°C of the pressure-sensitive adhesive layer (Y1) described below is appropriately reduced, and the flexibility of the pressure-sensitive adhesive layer (Y1) is further improved, thereby further improving the adhesive strength of the pressure-sensitive adhesive layer (Y1) to the fluororesin. The softening temperature of the tackifier resin (T2) more preferably has a lower limit of 70°C and an upper limit of 150°C. The softening temperature of the tackifier resin (T2) is the softening temperature measured according to JIS K 2207 (ring and ball method).

[0098] The tackifier resin (T2) preferably has a lower limit of 0 mgKOH / g and an upper limit of 200 mgKOH / g for the hydroxyl value. When the tackifier resin (T2) has a hydroxyl value within the above range, the wettability of the interface of the pressure-sensitive adhesive layer (Y1) is improved, and interfacial peeling can be suppressed. The hydroxyl value of the tackifier resin (T2) is more preferably 30 mgKOH / g for the lower limit and 130 mgKOH / g for the upper limit. The hydroxyl value can be measured according to JIS K 1557 (phthalic anhydride method).

[0099] Examples of the rosin ester resin include Pine Crystal KE-359 (manufactured by Arakawa Chemical Industries, Ltd., hydroxyl value: 40 mgKOH / g, softening temperature: 100° C.). Examples of the terpene resin include YS Resin PX1250 (manufactured by Yasuhara Chemical Co., Ltd., hydroxyl value: 0 mgKOH / g, softening temperature: 125° C.). Examples of the terpene phenol resin include YS Polyster G150 (manufactured by Yasuhara Chemical Co., Ltd., hydroxyl value: 120 mgKOH / g, softening temperature: 150° C.). Examples of the petroleum-based resin include Alcon P-140 (manufactured by Arakawa Chemical Industries, Ltd., hydroxyl value: 0 mgKOH / g, softening temperature: 140° C.).

[0100] The content of the tackifier resin (T2) relative to 100 parts by mass of the base polymer (P1) is preferably 10 parts by mass or more at a lower limit and 200 parts by mass or more at a higher limit. When the content of the tackifier resin (T2) is 10 parts by mass or more, the adhesive strength of the adhesive layer (Y1) can be further increased. When the content of the tackifier resin (T2) is 200 parts by mass or less, the adhesive strength of the adhesive layer (Y1) can be prevented from decreasing due to excessive hardness. The lower limit of the content of the tackifier resin (T2) is more preferably 15 parts by mass, and the upper limit is more preferably 160 parts by mass, even more preferably 140 parts by mass, still more preferably 100 parts by mass, particularly preferably 60 parts by mass, extremely preferably 50 parts by mass, and most preferably 40 parts by mass.

[0101] When the base polymer (P1) contains a (meth)acrylic copolymer, the adhesive layer (Y1) preferably further contains a curing agent. When the adhesive layer (Y1) contains a curing agent, the (meth)acrylic copolymer can form a structure crosslinked by chemical crosslinking, thereby further improving the cohesive strength of the bulk of the adhesive layer (Y1) and further increasing the gel fraction of the adhesive layer (Y1), which will be described later, thereby further improving the adhesive strength of the adhesive sheet obtained.

[0102] Examples of the curing agent include an isocyanate-based curing agent, an aziridine-based curing agent, an epoxy-based curing agent, a metal chelate-type curing agent, etc. Among these, the curing agent preferably contains an isocyanate-based curing agent, from the viewpoint of enabling appropriate chemical crosslinking of the (meth)acrylic copolymer and further improving the adhesive strength of the adhesive layer (Y1).

[0103] Examples of the isocyanate curing agent include Takenate 500 (manufactured by Mitsui Chemicals, Inc.) and Desmodur L-75 (manufactured by Covestro).

[0104] The content of the curing agent relative to 100 parts by mass of the (meth)acrylic copolymer is preferably 0.01 parts by mass at the lower limit and 10 parts by mass at the upper limit. When the content of the curing agent is within the above range, appropriate chemical crosslinking of the (meth)acrylic copolymer is possible, and the adhesive strength of the resulting adhesive sheet is further improved. The lower limit of the content of the curing agent is more preferably 0.1 parts by mass, and the upper limit is more preferably 5.0 parts by mass, and the even more preferred lower limit is 0.5 parts by mass, and the even more preferred upper limit is 2.0 parts by mass.

[0105] When the base polymer (P1) contains the silicone resin, the adhesive layer (Y1) preferably further contains a catalyst. When the adhesive layer (Y1) contains the catalyst, the silicone resin can form a structure in which it is appropriately crosslinked, thereby further improving the bulk cohesive strength of the adhesive layer (Y1) and further increasing the gel fraction of the adhesive layer (Y1), which will be described later, thereby further improving the adhesive strength of the adhesive layer (Y1).

[0106] The catalyst may be, for example, a platinum catalyst. An example of the platinum catalyst is CAT-PL-50T (manufactured by Shin-Etsu Chemical Co., Ltd.).

[0107] The content of the catalyst relative to 100 parts by mass of the silicone resin is preferably 0.1 parts by mass at the lower limit and 10 parts by mass at the upper limit. When the content of the catalyst is within the above range, appropriate crosslinking of the silicone resin is possible, and the adhesive strength of the obtained adhesive sheet is further improved. The lower limit of the content of the catalyst is more preferably 0.2 parts by mass, and the upper limit is more preferably 8 parts by mass, and the even more preferably lower limit is 0.3 parts by mass, and the even more preferably upper limit is 6 parts by mass.

[0108] The pressure-sensitive adhesive layer (Y1) may further contain a colorant for the purpose of imparting light-blocking properties. Examples of the colorant include carbon black, aniline black, titanium oxide, etc. Among these, carbon black is preferred because it is relatively inexpensive and chemically stable.

[0109] The pressure-sensitive adhesive layer (Y1) may contain conventionally known fine particles and additives, such as inorganic fine particles, conductive fine particles, antioxidants, foaming agents, organic fillers, and inorganic fillers, as required.

[0110] The pressure-sensitive adhesive layer (Y1) is required to exhibit sufficient adhesive strength immediately after being attached to the adherend at room temperature, and therefore is preferably not a hot-melt pressure-sensitive adhesive layer. In this specification, the term "hot melt adhesive layer" refers to an adhesive layer that is melted by heating and adheres to an adherend.

[0111] In the second configuration, the adhesive layer (Y1) has a lower limit of 180° peel strength from polytetrafluoroethylene at 23°C of 5.0 N / 25 mm. When the adhesive layer (Y1) has a 180° peel strength from polytetrafluoroethylene at 23°C of 5.0 N / 25 mm or more, the adhesive sheet of the present invention has excellent adhesive strength to fluororesins. In the second configuration, the lower limit of the 180° peel strength from polytetrafluoroethylene at 23°C of the adhesive layer (Y1) is preferably 7.0 N / 25 mm, more preferably 10.0 N / 25 mm. In the first configuration, the adhesive layer (Y1) preferably has a lower limit of 2.5 N / 25 mm in 180° peel strength from polytetrafluoroethylene at 23°C. When the adhesive layer (Y1) has a 180° peel strength from polytetrafluoroethylene at 23°C of 2.5 N / 25 mm or more, the adhesive sheet of the present invention has superior adhesive strength to fluororesins. In the second configuration, the adhesive layer (Y1) more preferably has a lower limit of 3.0 N / 25 mm, and even more preferably 3.5 N / 25 mm in 180° peel strength from polytetrafluoroethylene at 23°C. Further, although there is no particular upper limit to the 180° peel strength of the adhesive layer (Y1) against polytetrafluoroethylene at 23° C., the substantial upper limit is about 100 N / 25 mm. The 180° peel strength of the pressure-sensitive adhesive layer (Y1) at 23° C. against polytetrafluoroethylene can be measured by the following method. That is, the adhesive sheet is cut into a size of 25 mm wide x 100 mm long, and then pressed onto a 2 μm thick polytetrafluoroethylene plate (Yodogawa Hutech Co., Ltd., "Yodoflon" or the like) using a 2 kg rubber roller, by moving it back and forth once at a speed of 300 mm / min. This is then left to stand for 20 minutes in an environment of 23°C and 50% RH to cure, thereby preparing a test sample. The obtained test sample is subjected to a 180° peel test in accordance with JIS Z 0237 using a tensile tester (ORIENTEC Co., Ltd., "Tensilon" or the like) under conditions of 23°C, 50% RH, and a peel rate of 300 mm / min, and the adhesive sheet is peeled from the polytetrafluoroethylene plate, whereby the 180° peel strength of the adhesive layer (Y1) at 23°C against polytetrafluoroethylene can be measured.

[0112]

[0063] Examples of a method for adjusting the 180° peel strength of the adhesive layer (Y1) at 23°C against polytetrafluoroethylene within the above-mentioned range include a method of changing the type or structural unit of the base polymer (P1) contained in the adhesive layer (Y1) (for example, the copolymerization ratio or composition of P1), a method of adjusting the type or content of a tackifier resin contained in the adhesive layer (Y1), a method of changing the thickness of the adhesive layer (Y1), a method of changing the base material, and the like.

[0113] The pressure-sensitive adhesive layer (Y1) preferably has a loss tangent (tan δ) measured at a frequency of 10 Hz in a dynamic viscoelastic measurement (hereinafter sometimes referred to as "the loss tangent of the pressure-sensitive adhesive layer (Y1) measured at a frequency of 10 Hz") that has a peak in a temperature range of -30°C or more and 15°C or less. When the loss tangent (tan δ) of the pressure-sensitive adhesive layer (Y1) measured at a frequency of 10 Hz has a peak in a temperature range of -30°C or more, the pressure-sensitive adhesive strength of the pressure-sensitive adhesive layer (Y1) to fluororesin is further improved. Furthermore, when the loss tangent (tan δ) of the pressure-sensitive adhesive layer (Y1) measured at a frequency of 10 Hz has a peak in a temperature range of 15°C or less, it is possible to suppress the zipping phenomenon that occurs when peeling off a film that protects the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet, and therefore the resulting pressure-sensitive adhesive sheet can be used without losing its pressure-sensitive adhesive strength. The peak temperature at which the loss tangent of the pressure-sensitive adhesive layer (Y1) measured at a frequency of 10 Hz reaches a peak (hereinafter, may be simply referred to as "peak temperature of loss tangent") is more preferably -25°C, more preferably 13°C, still more preferably -20°C, and still more preferably 11°C.

[0114] The adhesive layer (Y1) has a preferable lower limit of the shear storage modulus at 25°C measured at a frequency of 10 Hz in dynamic viscoelasticity measurement of 1.0 × 10 4 Pa, with a preferred upper limit of 5.0 × 10 5 Pa. When the shear storage modulus at 25°C of the adhesive layer (Y1) is within the above range, the adhesive sheet to be obtained has superior adhesive strength. In addition, the flexibility of the adhesive layer (Y1) is excellent, and the adhesive strength of the adhesive layer (Y1) to fluororesins is further improved. A more preferable lower limit of the shear storage modulus at 25°C of the adhesive layer (Y1) is 3.0 × 10 4 Pa, and a more preferable upper limit is 4.0 × 10 5 Pa, and a more preferable lower limit is 5.0 × 10 4 Pa, and a more preferable upper limit is 3.5 × 10 5 It is Pa.

[0115] The peak temperature of the loss tangent of the adhesive layer (Y1) measured at a frequency of 10 Hz and the shear storage modulus of the adhesive layer (Y1) at 25°C can be measured by dynamic viscoelasticity measurement. Specifically, a measurement sample consisting of only the adhesive layer is prepared by laminating adhesive layers to a thickness of 1 mm, and the dynamic viscoelasticity spectrum of the obtained measurement sample is measured from -50°C to 200°C using a dynamic viscoelasticity measuring device such as a viscoelasticity spectrometer (e.g., "DVA-200" manufactured by IT Measurement & Control Co., Ltd.) under conditions of shear mode, heating rate of 5°C / min, and measurement frequency of 10 Hz, thereby measuring the shear storage modulus of the adhesive layer (Y1). Furthermore, the peak temperature of the loss tangent of the adhesive layer (Y1) can be obtained from the dynamic viscoelasticity spectrum obtained at this time.

[0116] The peak temperature of the loss tangent (tanδ) of the pressure-sensitive adhesive layer (Y1) measured at a frequency of 10 Hz and the shear storage modulus at 25°C of the pressure-sensitive adhesive layer (Y1) can be adjusted by the types and content ratios of monomers constituting the (meth)acrylic copolymer, the weight average molecular weight of the (meth)acrylic copolymer, the presence or absence of the tackifier resin (T2), the types and contents of the tackifier resin (T1) and the tackifier resin (T2), the gel fraction of the pressure-sensitive adhesive layer (Y1) described later, and the like.

[0117] The gel fraction of the adhesive layer (Y1) preferably has a lower limit of 0 mass% and an upper limit of 99 mass%. When the gel fraction of the adhesive layer (Y1) is 0 mass% or more, the bulk strength of the adhesive layer (Y1) increases, and the adhesive sheet obtained has superior adhesive strength. When the gel fraction of the adhesive layer (Y1) is 99 mass% or less, the shear storage modulus at 25°C of the adhesive layer (Y1) is appropriately reduced, the flexibility of the adhesive layer (Y1) is further improved, and the adhesive strength of the adhesive layer (Y1) to fluororesin is further improved. The gel fraction of the adhesive layer (Y1) is more preferably 10 mass% or less, and more preferably 70 mass% or less, and even more preferably 20 mass% or less, and even more preferably 65 mass% or less, and even more preferably 25 mass% or less, and even more preferably 60 mass% or less, and particularly preferably 50 mass% or less. The gel fraction of the adhesive layer (Y1) can be measured by the following method. The adhesive sheet is cut into a flat rectangular shape of 50 mm wide x 100 mm long to prepare a test specimen. The test specimen is immersed in an organic solvent at 23°C for 24 hours, then removed from the organic solvent and dried at 110°C for 1 hour. Note that the organic solvent can be ethyl acetate when the base polymer (P1) is a (meth)acrylic copolymer, or toluene when the base polymer (P1) is a styrene-based elastomer or silicone resin. The mass of the test specimen after drying is measured, and the gel fraction is calculated using the following formula (1). Note that no release film to protect the adhesive layer (Y1) is laminated on the test specimen. Gel fraction (mass%) = 100 × (W2 - W0) / (W1 - W0) (1) (W0: Mass of the substrate, W1: Mass of the test piece before immersion, W2: Mass of the test piece after immersion and drying)

[0118] The gel fraction of the pressure-sensitive adhesive layer (Y1) can be adjusted within the above range, for example, by adjusting the type and content ratio of the monomers constituting the (meth)acrylic copolymer, the weight average molecular weight of the (meth)acrylic copolymer, the type and content of the curing agent, etc.

[0119] The thickness of the adhesive layer (Y1) is preferably 25 μm at its lower limit and 1000 μm at its upper limit. If the thickness of the adhesive layer (Y1) is within this range, the adhesive layer (Y1) can have sufficient adhesive strength. The thickness of the adhesive layer (Y1) is more preferably 40 μm at its lower limit, more preferably 500 μm at its upper limit, even more preferably 50 μm at its lower limit, even more preferably 300 μm at its upper limit, still more preferably 80 μm at its lower limit, and particularly preferably 100 μm at its lower limit.

[0120] In the first configuration, the adhesive layer (Y2) is a hot-melt adhesive layer. In the second configuration, the adhesive layer (Y2) is preferably a hot-melt adhesive layer.

[0121] The preferred lower limit of the softening point of the adhesive layer (Y2) is 40° C. When the softening point of the adhesive layer (Y2) is 40° C. or higher, the adhesive sheet of the present invention has excellent lamination workability. The more preferred lower limit of the softening point of the adhesive layer (Y2) is 50° C., and the even more preferred lower limit is 60° C. The upper limit of the softening point of the adhesive layer (Y2) is preferably 250° C. When the softening point of the adhesive layer (Y2) is 250° C. or less, deterioration of the material during heating can be suppressed. The upper limit of the softening point of the adhesive layer (Y2) is more preferably 230° C., and even more preferably 200° C. The softening point of the adhesive layer (Y2) can be measured in accordance with JIS K6863.

[0122] The adhesive sheet has a 180° peel strength from SUS at 23°C (hereinafter sometimes simply referred to as "the 180° peel strength from SUS at 23°C of the adhesive layer (Y2) after heating") of 10 N / 25 mm, when the adhesive layer (Y2) side is pressure-bonded in a 150°C environment at 0.1 MPa for 10 minutes. When the adhesive layer (Y2) has a 180° peel strength from SUS at 23°C after heating of 10 N / 25 mm or more, the adhesive layer (Y2) can exhibit excellent adhesive strength upon heating, and therefore the adhesive sheet of the present invention can achieve both excellent lamination workability and excellent adhesive strength. The lower limit of the 180° peel strength from SUS at 23°C of the adhesive layer (Y2) after heating is preferably 15 N / 25 mm, and the upper limit is more preferably 20 N / 25 mm. Further, although there is no particular preferred upper limit to the 180° peel strength of the pressure-sensitive adhesive layer (Y2) from SUS at 23° C. after heating, the substantial upper limit is 500 N / 25 mm. The 180° peel strength of the pressure-sensitive adhesive layer (Y2) from SUS at 23° C. after heating can be measured by the following method. That is, the adhesive sheet is cut to a size of 25 mm wide x 100 mm long, and the adhesive layer (Y1) is backed with a 23 μm thick PET film (e.g., (FE2002) manufactured by Futamura Chemical Co., Ltd.), and the adhesive layer (Y1) is then pressure-bonded to a SUS plate (a SUS304 plate that has been washed with ethanol and then wiped dry) by applying a pressure of 0.1 MPa in an environment of 150°C for 10 minutes, followed by air cooling to prepare a test sample. The obtained test sample is subjected to a 180° peel test in accordance with JIS Z0237 using a tensile tester (e.g., "Tensilon" manufactured by ORIENTEC Co., Ltd.) under conditions of 23°C, 50% RH, and a peel rate of 300 mm / min, and the adhesive sheet is peeled from the SUS plate, whereby the 180° peel strength of the adhesive layer (Y2) against SUS at 23°C can be measured.

[0123] Examples of a method for adjusting the 180° peel strength from SUS at 23°C after heating of the adhesive layer (Y2) include a method of changing the composition of the base polymer (P3) described below of the adhesive layer (Y2) or a method of changing the thickness of the adhesive layer (Y2).

[0124] The adhesive layer (Y2) preferably contains a base polymer (P2). The base polymer (P2) preferably contains at least one selected from the group consisting of a (meth)acrylic copolymer, a styrene-based elastomer, an ethylene-vinyl acetate copolymer, a chloroprene rubber, a nitrile rubber, a polyurethane resin, a polyamide resin, a polyolefin resin, a polyester resin, an epoxy resin, and a silicone resin. Among these, from the viewpoints of easily controlling the probe tack value (described later) and further improving heat resistance, the base polymer (P2) more preferably contains at least one selected from the group consisting of a (meth)acrylic copolymer, a styrene-based elastomer, a chloroprene rubber, a nitrile rubber, a polyurethane resin, a polyamide resin, a polyolefin resin, and a polyester resin.

[0125] The (meth)acrylic copolymer, styrene-based elastomer, and silicone resin in the base polymer (P2) may be the same as those in the base polymer (P1). Specific examples of the (meth)acrylic copolymer in the base polymer (P2) include SK Dyne 1717DT and SK Dyne 1515DT (both manufactured by Soken Chemical & Engineering Co., Ltd.). Specific examples of the styrene-based elastomer in the base polymer (P2) include GR-1160 (manufactured by Big Technos Co., Ltd.) and Quintac 3270 (manufactured by Zeon Corporation). Specific examples of the silicone resin in the base polymer (P2) include KR-101-10 (manufactured by Shin-Etsu Chemical Co., Ltd.).

[0126] An example of the ethylene-vinyl acetate copolymer is HM200 (manufactured by Cemedine Co., Ltd.). Examples of the chloroprene rubber include 575F (manufactured by Cemedine Co., Ltd.) and G17 (manufactured by Konishi Co., Ltd.). An example of the nitrile rubber is 501F (manufactured by Cemedine Co., Ltd.). Examples of the polyurethane resin include SHM107-PUR (manufactured by Sheedom Co., Ltd.). An example of the polyamide resin is SHM301-PAD (manufactured by Sheedom Co., Ltd.). An example of the polyolefin resin is PPET1401SG (manufactured by Toagosei Co., Ltd.). An example of the polyester resin is PH-413 (manufactured by Nihon Matai Co., Ltd.). The epoxy resin may be, for example, 1500 (manufactured by Cemedine Co., Ltd.).

[0127] From the viewpoint of further improving the adhesive strength, the adhesive layer (Y2) preferably further contains a tackifier resin (T3). Examples of the tackifier resin (T3) include those similar to the tackifier resin (T2) described above.

[0128] When the base polymer (P2) contains the (meth)acrylic copolymer, the adhesive layer (Y2) preferably further contains a curing agent. When the adhesive layer (Y2) contains the curing agent, the (meth)acrylic copolymer forms a structure crosslinked by chemical crosslinking, and the adhesive strength of the obtained adhesive sheet is further improved.

[0129] As the curing agent contained in the adhesive layer (Y2), for example, the same curing agent as that contained in the adhesive layer (Y1) can be used.

[0130] The pressure-sensitive adhesive layer (Y2) may contain conventionally known fine particles and additives, such as inorganic fine particles, conductive fine particles, antioxidants, foaming agents, organic fillers, and inorganic fillers, as required.

[0131] In the second configuration, the upper limit of the probe tack value of the adhesive layer (Y2) measured under conditions of 23°C, a pressure of 98 gf, a pressure application rate of 100 mm / sec, a pressure application time of 10 seconds, and a peeling rate of 5 mm / sec (hereinafter, sometimes simply referred to as "the probe tack value of the adhesive layer (Y2) at 23°C") is 20 N / 5 mmφ. When the probe tack value of the adhesive layer (Y2) at 23°C is 20 N / 5 mmφ or less, the stickiness of the adhesive layer (Y2) can be suppressed, and the adhesive sheet of the present invention becomes excellent in lamination workability. In the second configuration, the upper limit of the probe tack value of the adhesive layer (Y2) at 23°C is preferably 15 N / 5 mmφ, more preferably 10 N / 5 mmφ. In the first configuration, the upper limit of the probe tack value of the adhesive layer (Y2) at 23°C is preferably 20 N / 5 mmφ. When the probe tack value of the adhesive layer (Y2) at 23°C is 20 N / 5 mmφ or less, the stickiness of the adhesive layer (Y2) can be suppressed, and the adhesive sheet of the present invention has better lamination workability. In the first configuration, the upper limit of the probe tack value of the adhesive layer (Y2) at 23°C is more preferably 15 N / 5 mmφ, and even more preferably 10 N / 5 mmφ. The preferred lower limit of the probe tack value of the adhesive layer (Y2) at 23°C is 0.01 N / 5 mmφ. When the adhesive layer (Y2) has a probe tack value of 0.01 N / 5 mmφ or more at 23°C, the adhesive layer (Y2) has an appropriate adhesive strength, and from the viewpoint of making it easier to adjust the bonding position of the adhesive sheet of the present invention, the bonding workability becomes more excellent. The more preferred lower limit of the probe tack value of the adhesive layer (Y2) at 23°C is 0.1 N / 5 mmφ, and the even more preferred lower limit of the probe tack value of the adhesive layer (Y2) at 23°C is 1.0 N / 5 mmφ. The probe tack value of the pressure-sensitive adhesive layer (Y2) at 23° C. can be measured by a probe tack test in accordance with JIS Z 3284. Specifically, for example, the pressure-sensitive adhesive sheet of the present invention is cut into a size of 30 mm in width × 30 mm in length to prepare a test piece, and the pressure-sensitive adhesive layer (Y2) of the prepared test piece is subjected to a probe tack test using a probe tack tester (manufactured by RHESCA, "TAC-2" or the like) under conditions of 23°C, a pressure of 98 gf, a pressure application rate of 100 mm / sec, a pressure application time of 10 seconds, and a peeling rate of 5 mm / sec, thereby measuring the tackiness.

[0132] Examples of a method for adjusting the probe tack value at 23°C of the pressure-sensitive adhesive layer (Y2) include a method for changing the composition or content ratio of the base polymer (P2) or the tackifier resin (T3), and a method for changing the thickness of the pressure-sensitive adhesive (Y2).

[0133] The thickness of the adhesive layer (Y2) is preferably 20 μm at its lower limit and 100 μm at its upper limit. When the thickness of the adhesive layer (Y2) is within this range, the adhesive layer (Y2) can have sufficient adhesive strength. The thickness of the adhesive layer (Y2) is more preferably 25 μm at its lower limit and 80 μm at its upper limit.

[0134] The adhesive sheet of the present invention may have layers other than the adhesive layer (Y1) and the adhesive layer (Y2), if necessary.

[0135] The adhesive sheet of the present invention preferably further comprises a substrate layer between the adhesive layer (Y1) and the adhesive layer (Y2). By having the above-mentioned base material layer, the adhesive sheet of the present invention is less likely to cause interlayer cracking, thereby improving the adhesive strength, and also making it possible to prevent component migration between the adhesive layer (Y1) and the adhesive layer (Y2).

[0136] From the viewpoint of substrate strength, the substrate layer preferably contains at least one selected from the group consisting of polyester resin, polyimide resin, polyether resin, polyolefin resin, polyurethane resin, metal, glass fiber, and carbon fiber. Among these, from the viewpoint of higher adhesiveness, heat resistance, and chemical resistance, the substrate layer more preferably contains at least one selected from the group consisting of polyester resin, polyimide resin, polyether resin, glass fiber, and carbon fiber.

[0137] Examples of the polyester resin include polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT), polyethylene furanoate (PEF), polylactic acid (PLA), and polybutylene succinate (PBS). Examples of the polyimide resin include Kapton (manufactured by DuPont) and Upilex (manufactured by UBE). Examples of the polyether resin include polyether ether ketone (PEEK) and polyetherimide (PEI). Examples of the polyolefin resin include polyethylene (PE), polypropylene (PP), and ethylene-vinyl acetate copolymer (EVA). The polyurethane resin is a resin composition composed of a polyisocyanate and a polyol. Examples of the polyisocyanate include 4,4'-diphenylmethane diisocyanate (MDI), and examples of the polyol include polypropylene glycol (PPG). Examples of the metal include SUS, copper, and aluminum. The glass fiber may be, for example, glass cloth. The carbon fiber may be, for example, carbon cloth.

[0138] Examples of the shape of the base material layer include a film, a nonwoven fabric, a woven fabric, etc. Among these, from the viewpoint of the base material layer exhibiting high anchor strength to the pressure-sensitive adhesive layer (Y1) and the pressure-sensitive adhesive layer (Y2), at least one selected from the group consisting of a nonwoven fabric and a woven fabric is preferred. An example of the nonwoven fabric substrate is G2260-1S (manufactured by Toray International Co., Ltd.). Examples of the woven substrate include glass cloth, carbon cloth, etc. Specific examples of the glass cloth include KS2770 (manufactured by Nitto Boseki Co., Ltd.), and specific examples of the carbon cloth include C-540 (manufactured by Hagiwara Kogyo Co., Ltd.).

[0139] The thickness of the base material layer is preferably 4 μm at its lower limit and 500 μm at its upper limit. When the thickness of the base material layer is within the above range, the reworkability of the obtained adhesive sheet is further improved. The thickness of the base material layer is more preferably 12 μm at its lower limit and 400 μm at its upper limit, still more preferably 23 μm at its lower limit and 300 μm at its upper limit, and particularly preferably 200 μm at its upper limit.

[0140] The method for producing the adhesive sheet of the present invention is not particularly limited, and for example, in the case of an adhesive sheet not having a base layer, the following method may be mentioned. First, a solvent is added to the base polymer (P1), a tackifying resin, and, if necessary, a curing agent to prepare a pressure-sensitive adhesive solution (a), which is then applied to the release-treated surface of a release PET film, and the solvent in the solution is completely dried and removed to produce a laminated film having a pressure-sensitive adhesive layer (Y1). Similarly, the pressure-sensitive adhesive solution (b) is applied to the release-treated surface of a release PET film, and the solvent in the solution is completely dried and removed to produce a laminated film having a pressure-sensitive adhesive layer (Y2). The pressure-sensitive adhesive layer (Y1) and the pressure-sensitive adhesive layer (Y2) are then stacked facing each other, and the resulting pressure-sensitive adhesive sheet is then cured for 48 hours in an environment of 40°C and 50% RH, thereby obtaining a pressure-sensitive adhesive sheet having no base layer. Alternatively, a substrate is prepared, and a pressure-sensitive adhesive layer (Y1) is superimposed on one surface of the substrate and a pressure-sensitive adhesive layer (Y2) is superimposed on the other surface of the substrate, and the resulting mixture is cured for 48 hours in an environment of 40°C and 50% RH, thereby obtaining a pressure-sensitive adhesive sheet having a substrate layer.

[0141] The adhesive sheet of the present invention is not particularly limited in its applications, but because it exhibits excellent adhesive strength to fluororesins such as polytetrafluoroethylene even without pretreatment, it is suitable for bonding fluororesins to dissimilar materials for a variety of purposes. More specifically, the various purposes include promoting sliding on friction surfaces, preventing friction between sliding parts, insulating coating, and protecting adherends from high temperatures and chemical solutions. It is particularly suitable for protecting adherends, particularly from chemical solutions. Furthermore, because the adhesive sheet of the present invention has excellent lamination workability, it is particularly suitable for use in bonding lining sheets to can bodies in chemical tanks, and is even more suitable when the chemical tank is a chemical tank for semiconductors or the chemical industry. In other words, a chemical tank to which the adhesive sheet of the present invention is attached is suitable for use in the semiconductor or chemical industry.

[0142] A laminated sheet having a sheet containing a fluororesin on the adhesive layer (Y1) side of the adhesive sheet of the present invention also constitutes the present invention. Furthermore, a chemical tank having the adhesive sheet of the present invention or the laminated sheet of the present invention attached to the inner surface of a can body, and a method for manufacturing a chemical tank including a step of attaching the laminated sheet of the present invention to the inside of the can body of the chemical tank, are also each part of the present invention. The method for producing a liquid chemical tank of the present invention preferably comprises the steps of: using the adhesive sheet of the present invention, pressing a sheet containing a fluororesin onto the adhesive layer (Y1) to produce a laminate sheet of the present invention; and laminating the adhesive layer (Y2) of the laminate sheet to the inside of a can body of the liquid chemical tank.

[0143] Examples of the sheet containing the fluororesin include a sheet containing polytetrafluoroethylene (PTFE), a sheet containing perfluoroalkoxyalkane (PFA), a sheet containing perfluoroethylenepropene copolymer (FEP), a sheet containing ethylenetetrafluoroethylene copolymer (ETFE), a sheet containing polyvinylidene fluoride (PVDF), a sheet containing polyvinyl fluoride (PVF), a sheet containing polychlorotrifluoroethylene (PCTFE), a sheet containing ethylenechlorotrifluoroethylene copolymer (ECTFE), etc. Among these, a sheet containing PTFE is preferred because of its excellent heat resistance and chemical resistance.

[0144] In the step of laminating the pressure-sensitive adhesive layer (Y2) of the laminated sheet to the inside of the can body of the chemical tank, it is preferable to heat the laminated sheet to bond the pressure-sensitive adhesive layer (Y2) to the inside of the can body.

[0145] In the method for manufacturing a chemical tank of the present invention, the chemical tank is preferably a chemical tank for semiconductors or a chemical tank for the chemical industry. [Effects of the Invention]

[0146] According to the present invention, it is possible to provide an adhesive sheet that has excellent adhesive strength to fluororesins such as polytetrafluoroethylene without pre-treating the fluororesins and that has excellent lamination workability. Furthermore, according to the present invention, it is possible to provide a laminated sheet using the adhesive sheet, and a method for manufacturing a chemical liquid tank using the adhesive sheet. DETAILED DESCRIPTION OF THE INVENTION

[0147] The following examples will explain the present invention in more detail, but the present invention is not limited to these examples.

[0148] (Preparation of Acrylic Copolymer) (Synthesis Example 1) A reactor equipped with a thermometer, stirrer, and condenser was charged with 100 parts by weight of ethyl acetate. After purging with nitrogen, the reactor was heated to initiate reflux. Thirty minutes after the ethyl acetate boiled, 0.08 parts by weight of azobisisobutyronitrile was added as a polymerization initiator. A monomer mixture of the structural unit monomers shown in Table 1 was added dropwise evenly and gradually over 1 hour and 30 minutes to allow the reaction to proceed. Thirty minutes after the dropwise addition was complete, 0.1 parts by weight of azobisisobutyronitrile was added, and the polymerization reaction was continued for an additional 5 hours. The reactor was then cooled while being diluted with ethyl acetate, yielding an acrylic copolymer solution with a solids content of 25% by weight. The resulting acrylic copolymer solution was filtered through a filter (material: polytetrafluoroethylene, pore diameter: 0.2 μm). The resulting filtrate was fed to a gel permeation chromatograph (Waters, 2690 Separations Module) and subjected to GPC measurement at a sample flow rate of 1 mL / min and a column temperature of 40°C. The polystyrene-equivalent molecular weight of the acrylic copolymer was measured, and the weight-average molecular weight (Mw) and molecular weight distribution (Mw / Mn) were determined. A GPC KF-806L (Showa Denko) column was used, and a differential refractometer was used as the detector. The results are shown in Table 1.

[0149] (Synthesis Examples 2 and 3) An acrylic copolymer was obtained in the same manner as in Synthesis Example 1, except that the monomer mixture was changed as shown in Table 1. The results are shown in Table 1.

[0150] The structural unit monomers shown in Table 1 are as follows: BA: n-butyl acrylate 2EHA: 2-ethylhexyl acrylate LA: Lauryl acrylate HEA: 2-hydroxyethyl acrylate AAc: acrylic acid

[0151] [Table 1]

[0152] (Preparation of Tackifier Resin (T1)) (Synthesis example A) A reactor equipped with a thermometer, stirrer, and condenser was charged with 50 parts by weight of toluene. The atmosphere was then purged with nitrogen, and the reactor was heated to initiate reflux. After 30 minutes, 2 parts by weight of aluminum chloride (AlCl3) was added while maintaining the toluene at 75°C. A solution of 50 parts by weight of catechol (pyrocatechol) (n = 2) and α-pinene (molar ratios shown in Table 2) dissolved in 50 parts by weight of toluene was gradually added dropwise over 1 hour and 30 minutes to allow the reaction to proceed. After 4 hours of polymerization, the reactor was cooled while adding 0.1 parts by weight of pyridine to neutralize the hydrochloric acid generated from the aluminum chloride (AlCl3). The precipitate formed during neutralization was filtered, and the resulting filtrate was separated. The toluene was then evaporated to obtain a solid tackifier resin (T1). Regarding the obtained tackifier resin (T1) 1 H-NMR measurement was carried out, and it was confirmed that the tackifier resin (T1) was a copolymer having a structural unit (A) derived from catechol (pyrocatechol) and a structural unit (B) derived from α-pinene (a copolymer having the structural unit (A) in the main chain skeleton or at the end of the main chain skeleton). The resulting tackifier resin (T1) was dissolved in tetrahydrofuran and the solution was filtered through a filter (material: polytetrafluoroethylene, pore diameter: 0.2 μm). The resulting filtrate was fed to a gel permeation chromatograph (Waters, 2690 Separations Module) and subjected to GPC measurement at a sample flow rate of 1 mL / min and a column temperature of 40°C. The polystyrene-equivalent molecular weight of the tackifier resin (T1) was measured and the weight-average molecular weight (Mw) was determined. A GPC KF-802.5L (Showa Denko) column was used, and a differential refractometer was used as the detector. The results are shown in Table 2.

[0153] (Measurement of the content of bio-derived carbon in tackifier resin (T1)) The content of bio-derived carbon in the resulting tackifier resin (T1) was measured in accordance with ASTM D6866-22, and the results are shown in Table 2.

[0154] (Synthesis Examples B to C and E) Tackifier resin (T1) was synthesized and measured in the same manner as in Synthesis Example A above in "(Preparation of tackifier resin (T1))", except that the monomers were changed as shown in Table 2. The results are shown in Table 2.

[0155] (Synthesis example D) (Preparation of Tackifier Resin (T1)) A reactor equipped with a thermometer, stirrer, and condenser was charged with 50 parts by weight of toluene. The atmosphere was then purged with nitrogen, and the reactor was heated to initiate reflux. After 30 minutes, 2 parts by weight of aluminum chloride (AlCl3) was added while maintaining the toluene at 75°C. A solution of 70 parts by weight of 4-vinylbenzoic acid (m = 1) and α-pinene (molar ratios shown in Table 2) dissolved in 50 parts by weight of toluene was gradually added dropwise over 1 hour and 30 minutes to allow the reaction to proceed. After 4 hours of polymerization, the reactor was cooled while adding 0.1 parts by weight of pyridine to neutralize the hydrochloric acid generated from the aluminum chloride (AlCl3). The precipitate formed during neutralization was filtered, and the resulting filtrate was separated. The toluene was then evaporated to obtain a solid tackifier resin (T1). Regarding the obtained tackifier resin (T1) 1 H-NMR measurement was carried out, and it was confirmed that the tackifier resin (T1) was a copolymer having a structural unit (A) derived from 4-vinylbenzoic acid and a structural unit (B) derived from α-pinene (a copolymer having the structural unit (A) in the side chain). The resulting tackifier resin (T1) was dissolved in tetrahydrofuran and the solution was filtered through a filter (material: polytetrafluoroethylene, pore diameter: 0.2 μm). The resulting filtrate was fed to a gel permeation chromatograph (Waters, 2690 Separations Module) and subjected to GPC measurement at a sample flow rate of 1 mL / min and a column temperature of 40°C. The polystyrene-equivalent molecular weight of the tackifier resin (T1) was measured and the weight-average molecular weight (Mw) was determined. A GPC KF-802.5L (Showa Denko) column was used, and a differential refractometer was used as the detector. The results are shown in Table 2.

[0156] (Measurement of the content of bio-derived carbon in tackifier resin (T1)) The content of bio-derived carbon in the resulting tackifier resin (T1) was measured in accordance with ASTM D6866-22, and the results are shown in Table 2.

[0157] [Table 2]

[0158] (Example 1-1) (1) Preparation of adhesive sheet To 100 parts by mass of the solid content of the acrylic copolymer (Synthesis Example 1), 10 parts by mass of tackifier resin (T1) (Synthesis Example A) and 20 parts by mass of tackifier resin (T2) (Pine Crystal KE-359, manufactured by Arakawa Chemical Industries, Ltd.) were added. Furthermore, 30 parts by mass of ethyl acetate (manufactured by Fuji Chemical Industries, Ltd.) and 0.5 parts by mass of an isocyanate-based curing agent (Desmodur L-75, manufactured by Covestro) were added and thoroughly stirred to obtain a pressure-sensitive adhesive solution (a). The obtained adhesive solution (a) was applied to the release-treated surface of a 75 μm-thick release PET film ("SP3000" manufactured by Toyo Cross Co., Ltd.) and dried at 100°C for 5 minutes to form an adhesive layer (Y1) with a thickness of 50 μm. SHM107-PUR (manufactured by Sheedom Co., Ltd.) was applied to the release-treated surface of a separately prepared 50 μm-thick release PET film to a thickness of 50 μm to form an adhesive layer (Y2). The obtained adhesive layer (Y1) and adhesive layer (Y2) were stacked facing each other, and then cured by heating at 150°C for 5 minutes. This resulted in an adhesive sheet having an adhesive layer (Y1) on one surface and an adhesive layer (Y2) on the other surface.

[0159] (2) Measurement of 180° peel strength from SUS at 23°C after heating the adhesive layer (Y2) The resulting adhesive sheet was cut to a size of 25 mm wide x 100 mm long, and the adhesive layer (Y1) was lined with a 23 μm thick PET film (Futamura Chemical Co., Ltd., "FE2002"), and the adhesive layer (Y1) was then bonded to a SUS plate (SUS304 plate that had been washed with ethanol and wiped dry) by applying a pressure of 0.1 MPa at 150°C for 10 minutes, followed by air cooling to prepare a test sample. The resulting test sample was subjected to a 180° peel test in accordance with JIS Z0237 using a tensile tester (ORIENTEC, "Tensilon") at 23°C, 50% RH, and a peel rate of 300 mm / min. The adhesive sheet was peeled from the SUS plate, and the 180° peel strength of the adhesive layer (Y2) against the SUS plate at 23°C was measured. The results are shown in Table 6.

[0160] (Examples 1-2 to 1-11, 1-17 to 1-28, Comparative Examples 1-3 to 1-5) The compositions and thicknesses of the adhesive layer (Y1) and the adhesive layer (Y2) were as shown in Tables 3 to 5, and adhesive sheets were prepared and measured in the same manner as in "(1) Preparation of adhesive sheet" in Example 1-1 above. The results are shown in Tables 6 to 8.

[0161] (Examples 1-12 to 1-16) Using the compositions and thicknesses shown in Tables 3 and 4, adhesive layers (Y1) and (Y2) were formed in the same manner as in "(1) Preparation of adhesive sheet" in Example 1-1 above. The substrates shown in Tables 3 and 4 were prepared, and a pressure-sensitive adhesive layer (Y1) was bonded to one surface of the substrate, and a pressure-sensitive adhesive layer (Y2) was bonded to the other surface of the substrate, thereby laminating and integrating them. Next, by heating in an environment of 150°C for 5 minutes, a pressure-sensitive adhesive sheet having a substrate, a pressure-sensitive adhesive layer (Y1) on one surface, and a pressure-sensitive adhesive layer (Y2) on the other surface was obtained. The measurement was carried out in the same manner as in "(2) Measurement of 180° peel strength from SUS at 23° C. after heating of the pressure-sensitive adhesive layer (Y2)" in Example 1-1. The results are shown in Tables 6 and 7.

[0162] (Comparative Examples 1-1 and 1-2) Using the compositions and thicknesses shown in Table 5, a pressure-sensitive adhesive layer (Y1) or a pressure-sensitive adhesive layer (Y2) was formed in the same manner as in "(1) Preparation of pressure-sensitive adhesive sheet" in Example 1-1 described above, and a 50 μm-thick release PET film was placed on top of the formed pressure-sensitive adhesive layer (Y1) or pressure-sensitive adhesive layer (Y2) with the release-treated side facing the film. This was then cured for 5 minutes in an environment at 100°C, thereby obtaining a pressure-sensitive adhesive sheet having a single layer pressure-sensitive adhesive layer (Y1) or pressure-sensitive adhesive layer (Y2). Measurement was carried out in the same manner as in "(2) Measurement of 180° peel strength from SUS at 23°C after heating of pressure-sensitive adhesive layer (Y2)" in Example 1-1 described above. The results are shown in Table 8.

[0111] In Comparative Examples 1-1 and 1-2, the adhesive sheets were single-layered, and therefore the single-layered adhesive layer could not be classified into an adhesive layer (Y1) and an adhesive layer (Y2). However, in the same measurements as in "(2) Measurement of 180° peel force from SUS at 23°C after heating of adhesive layer (Y2)" in Example 1-1 described above, and in the evaluations described below, the single-layered adhesive layer was the subject of measurement or evaluation.

[0163] <Evaluation> The adhesive sheets obtained in Examples 1-1 to 1-28 and Comparative Examples 1-1 to 1-5 were evaluated by the following methods. The results are shown in Tables 6 to 8.

[0164] (Adhesive strength to fluororesin) The resulting adhesive sheet was cut to a size of 25 mm wide x 100 mm long. The release PET film protecting the adhesive layer (Y1) of the cut adhesive sheet was peeled off, and the adhesive layer (Y1) was pressed against a 50 mm wide x 200 mm long x 2 mm thick polytetrafluoroethylene plate (Yodogawa Hutech Co., Ltd., "Yodoflon") using a 2 kg rubber roller, moving back and forth once at a speed of 300 mm / min, to prepare a test sample. The resulting test sample was subjected to a 180° peel test in accordance with JIS Z 0237 using a tensile tester (ORIENTEC Co., Ltd., "Tensilon" or the like) at 23°C, 50% RH, and a peel rate of 300 mm / min, to measure the 180° peel strength of the adhesive layer (Y1) against polytetrafluoroethylene at 23°C. The adhesive strength to the fluororesin was evaluated based on the following criteria: when the 180° peel strength of the obtained adhesive layer (Y1) against polytetrafluoroethylene at 23°C was 10 N / 25 mm or more, it was marked as "◎"; when it was 5.0 N / 25 mm or more and less than 10 N / 25 mm, it was marked as "○"; and when it was less than 5.0 N / 25 mm, it was marked as "×".

[0165] (Laminating workability) The obtained adhesive sheet was cut into a size of 25 mm wide x 100 mm long to prepare a test piece. A probe tack test was performed on the adhesive layer (Y2) of the prepared test piece using a probe tack tester (manufactured by RHESCA, "TAC-2") under conditions of 23°C, pressure of 98 gf, pressure application rate of 100 mm / sec, pressure application time of 10 seconds, and peeling rate of 5 mm / sec, and the probe tack value of the adhesive layer (Y2) at 23°C was measured. The adhesive layer (Y2) thus obtained had a probe tack value at 23°C of 10 N / 5 mmφ or less, which was evaluated as "◎", a value of more than 10 N / 5 mmφ but not more than 20 N / 5 mmφ, which was evaluated as "○", and a value of more than 20 N / 5 mmφ, which was evaluated as "×".

[0166] [Table 3]

[0167] [Table 4]

[0168] [Table 5]

[0169] [Table 6]

[0170] [Table 7]

[0171] [Table 8]

[0172] Example 2-1 (1) Preparation of adhesive sheet To 100 parts by mass of the solid content of the acrylic copolymer (Synthesis Example 1), 10 parts by mass of tackifier resin (T1) (Synthesis Example A) and 20 parts by mass of tackifier resin (T2) (Pine Crystal KE-359, manufactured by Arakawa Chemical Industries, Ltd.) were added. Furthermore, 30 parts by mass of ethyl acetate (manufactured by Fuji Chemical Industries, Ltd.) and 0.5 parts by mass of an isocyanate-based curing agent (Desmodur L-75, manufactured by Covestro) were added and thoroughly stirred to obtain a pressure-sensitive adhesive solution (a). The obtained adhesive solution (a) was applied to the release-treated surface of a 75 μm-thick release PET film ("SP3000" manufactured by Toyo Cross Co., Ltd.) and dried at 100°C for 5 minutes to form an adhesive layer (Y1) with a thickness of 50 μm. An adhesive layer (Y2) was also formed using an adhesive solution (b) with a different composition prepared in the same manner. The obtained adhesive layer (Y1) and adhesive layer (Y2) were then stacked facing each other and heated at 40°C for 48 hours for curing. This resulted in an adhesive sheet having an adhesive layer (Y1) on one surface and an adhesive layer (Y2) on the other surface.

[0173] (2) Measurement of 180° peel strength of adhesive layer (Y1) against polytetrafluoroethylene at 23°C The resulting adhesive sheet was cut to a size of 25 mm wide x 100 mm long, and then a 2 kg rubber roller was used to press the sheet against a 2 mm thick polytetrafluoroethylene sheet (Yodoflon, manufactured by Yodogawa Hutech Co., Ltd.) using a reciprocating motion at a speed of 300 mm / min. The adhesive layer (Y1) was then pressed against the sheet. The sheet was then left to stand for 20 minutes at 23°C and 50% RH to cure, thereby preparing a test sample. The resulting test sample was subjected to a 180° peel test in accordance with JIS Z 0237 using a tensile tester (such as Tensilon, manufactured by ORIENTEC Co., Ltd.) at 23°C, 50% RH, and a peel speed of 300 mm / min. The adhesive sheet was peeled from the polytetrafluoroethylene sheet, and the 180° peel strength of the adhesive layer (Y1) against polytetrafluoroethylene at 23°C was measured. The results are shown in Table 12.

[0174] (3) Measurement of probe tack value of adhesive layer (Y2) at 23°C The obtained adhesive sheet was cut into a size of 30 mm wide x 30 mm long to prepare a test piece. A probe tack test was performed on the adhesive layer (Y2) of the prepared test piece using a probe tack tester (e.g., "TAC-2" manufactured by RHESCA) under conditions of 23°C, pressure of 98 gf, pressure application rate of 100 mm / sec, pressure application time of 10 seconds, and peeling rate of 5 mm / sec, and the probe tack value of the adhesive layer (Y2) at 23°C was measured. The results are shown in Table 12.

[0175] (4) Measurement of 180° peel strength from SUS at 23°C after heating of adhesive layer (Y2) The resulting adhesive sheet was cut to a size of 25 mm wide x 100 mm long, and the adhesive layer (Y1) was backed with a 23 μm thick PET film (Futamura Chemical Co., Ltd., "FE2002"), and then pressure-bonded to a SUS plate (SUS304 plate washed with ethanol and wiped dry) by applying a pressure of 0.1 MPa at 150°C for 10 minutes, followed by air cooling to prepare a test sample. The resulting test sample was subjected to a 180° peel test in accordance with JIS Z 0237 using a tensile tester (such as ORIENTEC's "Tensilon") at 23°C, 50% RH, and a peel rate of 300 mm / min. The adhesive sheet was peeled from the SUS plate, and the 180° peel strength of the adhesive layer (Y2) against the SUS plate at 23°C was measured. The results are shown in Table 12.

[0176] (Examples 2-3, 2-4, 2-6, 2-7, 2-9 to 2-12, 2-18 to 2-23, 2-25, 2-28, 2-29, Comparative Example 2-4) The compositions and thicknesses of the adhesive layer (Y1) and the adhesive layer (Y2) were as shown in Tables 9 to 11, and adhesive sheets were prepared and measurements were carried out in the same manner as in "(1) Preparation of adhesive sheet" in Example 2-1 above. The results are shown in Tables 12 to 14.

[0177] (Examples 2-2, 2-5, 2-8, 2-13 to 2-17, 2-24, 2-26, 2-27, Comparative Examples 2-5 and 2-6) After obtaining a pressure-sensitive adhesive solution (a) in the same manner as in Example 2-1, the obtained pressure-sensitive adhesive solution (Y1) was applied to the release-treated surface of a 75 μm-thick release PET film and dried at 100°C for 5 minutes to form a pressure-sensitive adhesive layer (Y1) with a thickness shown in Tables 9 to 11. Separately, a base polymer (P2) shown in Tables 9 to 11 was applied to the release-treated surface of a 75 μm-thick release PET film that had been prepared, so that the thickness after drying would be the thickness shown in Tables 9 to 11 to form a pressure-sensitive adhesive layer (Y2). The obtained pressure-sensitive adhesive layer (Y2) was bonded to the pressure-sensitive adhesive layer (Y1), or a laminate was obtained by preparing a substrate shown in Tables 9 and 10, bonding the pressure-sensitive adhesive layer (Y1) to one surface of the substrate, and bonding the pressure-sensitive adhesive layer (Y2) to the other surface of the substrate. The obtained laminate was heated in an environment of 40°C for 48 hours to obtain an adhesive sheet having an adhesive layer (Y1) on one surface and an adhesive layer (Y2) on the other surface. Measurements were carried out in the same manner as in "(2) Measurement of 180° peel strength of adhesive layer (Y1) from polytetrafluoroethylene at 23°C," "(3) Measurement of probe tack value of adhesive layer (Y2) at 23°C," and "(4) Measurement of 180° peel strength of adhesive layer (Y2) from SUS at 23°C after heating" in Example 2-1. The results are shown in Tables 12 to 14.

[0178] (Comparative Examples 2-1 to 2-3) Using the compositions and thicknesses shown in Table 11, a pressure-sensitive adhesive layer (Y1) or a pressure-sensitive adhesive layer (Y2) was formed in the same manner as in "(1) Preparation of pressure-sensitive adhesive sheet" in Example 2-1 described above, and a release PET film having a thickness of 75 μm was attached thereto, followed by curing for 48 hours in an environment of 40° C., thereby obtaining pressure-sensitive adhesive sheets having a single-layer pressure-sensitive adhesive layer (Y1) or a single-layer pressure-sensitive adhesive layer (Y2). Measurements were carried out in the same manner as in "(2) Measurement of the 180° peel strength of the adhesive layer (Y1) from polytetrafluoroethylene at 23°C," "(3) Measurement of the probe tack value of the adhesive layer (Y2) at 23°C," and "(4) Measurement of the 180° peel strength of the adhesive layer (Y2) from SUS at 23°C after heating" in Example 2-1. The results are shown in Table 14. In Comparative Examples 2-1 to 2-3, the adhesive sheets were single-layered, and therefore the single-layered adhesive layer could not be classified into an adhesive layer (Y1) and an adhesive layer (Y2). However, in the same measurements as in "(2) Measurement of the 180° peel force of the adhesive layer (Y2) from SUS at 23°C after heating," "(3) Measurement of the probe tack value of the adhesive layer (Y2) at 23°C," and "(4) Measurement of the 180° peel force of the adhesive layer (Y2) from SUS at 23°C after heating" in Example 2-1 described above, and in the evaluations described below, the single-layered adhesive layer was the subject of measurement or evaluation.

[0179] <Evaluation> The adhesive sheets obtained in Examples 2-1 to 2-29 and Comparative Examples 2-1 to 2-6 were evaluated by the following methods, and the results are shown in Tables 12 to 14.

[0180] (Laminating workability) The resulting adhesive sheet was cut to a size of 25 mm wide x 100 mm long. The release PET film protecting the adhesive layer (Y1) of the cut adhesive sheet was peeled off, and the adhesive layer (Y1) was pressed onto a 50 mm wide x 200 mm long x 2 mm thick polytetrafluoroethylene plate (Yodogawa Hutech Co., Ltd., "Yodoflon") using a 2 kg rubber roller, which was rolled back and forth at a speed of 300 mm / min, to produce a laminate. Furthermore, the release PET film protecting the adhesive layer (Y2) of the resulting laminate was peeled off, and the adhesive layer (Y2) was attached using a 5 mm diameter SUS probe at 23°C, a pressure of 98 gf, a pressure rate of 100 mm / sec, and a pressure time of 10 seconds. After leaving the sample to stand for 10 minutes in an environment of 23°C and 50% RH, the adhesive layer (Y2) was peeled off from the SUS at a peeling speed of 5 mm / sec, and then the surface of the adhesive layer (Y2) and the adhesive surface between the polytetrafluoroethylene and the adhesive layer (Y1) were observed visually and with an optical microscope. The evaluation of the lamination workability was performed by assigning "◎" to a case where the observed surface of the adhesive layer (Y2) was not roughened and did not peel off from the polytetrafluoroethylene, "○" to a case where the surface of the adhesive layer (Y2) was roughened during the lamination work but the adhesive layer (Y1) did not peel off from the polytetrafluoroethylene, and "×" to a case where the surface of the adhesive layer (Y2) was roughened during the lamination work and the adhesive layer (Y1) peeled off from the polytetrafluoroethylene.

[0181] [Table 9]

[0182] [Table 10]

[0183] [Table 11]

[0184] [Table 12]

[0185] [Table 13]

[0186] [Table 14] [Industrial Applicability]

[0187] According to the present invention, it is possible to provide an adhesive sheet that has excellent adhesive strength to fluororesins such as polytetrafluoroethylene without pre-treating the fluororesins and that has excellent lamination workability. Furthermore, according to the present invention, it is possible to provide a laminated sheet using the adhesive sheet, and a method for manufacturing a chemical liquid tank using the adhesive sheet.

Claims

1. A pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer (Y1) on one surface and a pressure-sensitive adhesive layer (Y2) on the other surface, The present invention has at least one structure selected from the group consisting of the following first structure and the following second structure: A pressure-sensitive adhesive sheet characterized by: First configuration: the pressure-sensitive adhesive layer (Y1) contains a base polymer (P1) and a tackifier resin, the base polymer (P1) contains at least one selected from the group consisting of a (meth)acrylic copolymer, a styrene-based elastomer, and a silicone resin; The adhesive layer (Y2) is a hot-melt adhesive layer. Second configuration: the pressure-sensitive adhesive layer (Y1) has a 180° peel strength from polytetrafluoroethylene at 23°C of 5.0 N / 25 mm or more, The pressure-sensitive adhesive layer (Y2) has a probe tack value of 20 N / 5 mmφ or less, measured under conditions of 23° C., a pressure of 98 gf, a pressure-applying speed of 100 mm / sec, a pressure-applying time of 10 seconds, and a peeling speed of 5 mm / sec.

2. having the first configuration, 2. The adhesive sheet according to claim 1, wherein the adhesive layer (Y1) has a 180° peel strength from polytetrafluoroethylene at 23° C. of 2.5 N / 25 mm or more.

3. having the second configuration, the pressure-sensitive adhesive layer (Y1) contains a base polymer (P1) and a tackifying resin, The adhesive sheet according to claim 1 , wherein the base polymer (P1) comprises at least one selected from the group consisting of a (meth)acrylic copolymer, a styrene-based elastomer, and a silicone resin.

4. The adhesive sheet according to claim 1, 2 or 3, wherein the softening point of the adhesive layer (Y2) is 40°C or higher.

5. 5. The adhesive sheet according to claim 1, wherein the adhesive sheet has a 180° peel strength from SUS at 23°C of 10 N / 25 mm or more when the adhesive layer (Y2) side is pressure-bonded to SUS at 23°C under a pressure of 0.1 MPa for 10 minutes in an environment of 150°C.

6. the pressure-sensitive adhesive layer (Y2) contains a base polymer (P2), 6. The adhesive sheet according to claim 1, 2, 3, 4 or 5, wherein the base polymer (P2) comprises at least one selected from the group consisting of a (meth)acrylic copolymer, a styrene-based elastomer, an ethylene-vinyl acetate copolymer, a chloroprene rubber, a nitrile rubber, a polyurethane resin, a polyamide resin, a polyolefin resin, a polyester resin, an epoxy resin, and a silicone resin.

7. The adhesive layer (Y1) has the first structure or the second structure, and the adhesive layer (Y1) contains a tackifier resin, The adhesive sheet according to claim 1, 2, 3, 4, 5 or 6, wherein the tackifier resin comprises a tackifier resin (T1) having at least one structural unit (A) selected from the group consisting of the structural unit (A-1), the structural unit (A-1'), the structural unit (A-2), the structural unit (A-2'), the structural unit (A-3), the structural unit (A-3'), the structural unit (A-4), and the structural unit (A-4') represented by the following formula: 【Chemistry 1】 【Chemistry 2】 【Transformation 3】 【Chemistry 4】 In the formula, R １ ~R ７ each represents a hydrogen atom, an aliphatic hydrocarbon group, an aromatic hydrocarbon group, a polar functional group, an aliphatic hydrocarbon group having a polar functional group, or an aromatic hydrocarbon group having a polar functional group. n and l each represent an integer of 2 or more and 4 or less, and n' and l' each represent an integer of 2 or more and 5 or less. m and k each represent an integer of 1 or more and 4 or less, and m' and k' each represent an integer of 1 or more and 5 or less. * represents a linking portion.

8. The adhesive sheet according to claim 7 , wherein the tackifier resin (T1) further comprises a structural unit (B) derived from at least one monomer (b) selected from the group consisting of terpene-based monomers and vinyl-based monomers.

9. The adhesive layer (Y1) has the first structure or the second structure, and the adhesive layer (Y1) contains a tackifier resin, 9. The adhesive sheet according to claim 1, wherein the tackifier resin comprises at least one tackifier resin (T2) selected from the group consisting of rosin ester resins, terpene resins, terpene phenol resins, and petroleum-based resins.

10. The adhesive sheet according to claim 1 , wherein the adhesive layer (Y1) is not a hot-melt adhesive layer.

11. The adhesive sheet according to claim 1 , 2, 3, 4, 5, 6, 7, 8, 9 or 10, wherein the adhesive layer (Y1) has a thickness of 25 μm or more and 1000 μm or less.

12. The adhesive sheet according to claim 1 , further comprising a substrate layer between the adhesive layer (Y1) and the adhesive layer (Y2).

13. The adhesive sheet according to claim 12, wherein the substrate layer contains at least one selected from the group consisting of polyester resin, polyimide resin, polyether resin, polyolefin resin, polyurethane resin, metal, glass fiber, and carbon fiber.

14. The adhesive sheet according to claim 12 or 13, wherein the substrate layer is made of at least one material selected from the group consisting of a nonwoven fabric and a woven fabric.

15. 15. The adhesive sheet according to claim 1, which is used to join a lining sheet to a tank body in a chemical tank.

16. The adhesive sheet according to claim 15, wherein the chemical tank is a chemical tank for semiconductors or a chemical tank for the chemical industry.

17. 17. A laminated sheet comprising a sheet containing a fluororesin on the adhesive layer (Y1) side of the adhesive sheet according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or 16.

18. 18. A chemical tank having the adhesive sheet according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or 16 or the laminated sheet according to claim 17 attached to the inner surface of a can body.

19. A method for manufacturing a chemical tank, comprising the step of laminating the laminated sheet according to claim 17 to the inside of a can body of the chemical tank.

20. The adhesive sheet according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or 16 is used, a step of pressure-bonding a sheet containing a fluororesin to the pressure-sensitive adhesive layer (Y1) to produce the laminate sheet according to claim 17; The method for manufacturing a liquid chemical tank according to claim 19, further comprising the step of attaching the pressure-sensitive adhesive layer (Y2) of the laminated sheet to the inside of a can body of the liquid chemical tank.

21. 21. The method for manufacturing a chemical tank according to claim 20, wherein in the step of bonding the pressure-sensitive adhesive layer (Y2) of the laminated sheet to the inside of a can body of the chemical tank, the laminated sheet is heated to bond the pressure-sensitive adhesive layer (Y2) to the inside of the can body.

22. 22. The method for manufacturing a chemical tank according to claim 19, 20 or 21, wherein the chemical tank is a chemical tank for semiconductors or a chemical tank for the chemical industry.

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