Method for manufacturing a wound body and a chemical tank, and a chemical tank

Abstract

The present invention provides a wound material that exhibits minimal floating (tunneling), offers excellent handling properties, and allows for easy bonding of fluororesin to a tank or the like. It also provides a method for manufacturing a chemical tank using this wound material. Furthermore, it provides a chemical tank with a laminated sheet attached to the wound material. [Solution] A winding body having a structure in which a laminated sheet is wound around a core, wherein the outer diameter of the core is 220 mm or more and 550 mm or less, and the laminated sheet comprises a resin sheet containing fluororesin and a double-sided adhesive sheet having an adhesive layer.

Description

[Technical Field]

[0001] This invention relates to a wound body. Furthermore, this invention relates to a method for manufacturing a chemical tank using the wound body. Moreover, this invention relates to a chemical tank in which a laminated sheet is attached to the wound body. [Background technology]

[0002] Conventionally, adhesive tape has been widely used to fix various components. Specifically, for example, adhesive tape is used to adhere a cover panel to protect the surface of a portable electronic device to a touch panel module or display panel module, or to bond a touch panel module to a display panel module. In addition to high adhesiveness, adhesive tape used to fix such components is required to have functions such as heat resistance, thermal conductivity, and impact resistance, depending on the environment in which it is used (for example, Patent Documents 1 to 3). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2015-052050 [Patent Document 2] Japanese Patent Publication No. 2015-021067 [Patent Document 3] Japanese Patent Publication No. 2015-120876 [Overview of the project] [Problems that the invention aims to solve]

[0004] In recent years, the 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, polytetrafluoroethylene (PTFE) is used in a wide range of applications, such as wire insulation and building materials, due to its high mechanical strength and excellent processability.

[0005] In the semiconductor and chemical industries, many chemical solutions such as acids and alkalis are used. When storing or disposing of chemical solutions, lining tanks with fluororesin bonded to the tank body are widely used for the purpose of corrosion prevention. Conventionally, when bonding fluororesin to the tank body, adhesives such as chloroprene rubber and epoxy resin have been used for the fluororesin and the tank body respectively. However, after applying these adhesives, high-temperature treatments such as a process of drying the solvent until bonding the fluororesin and a process of thermally curing the adhesive at high temperature are required. Therefore, the working efficiency is poor and it takes time for construction. Also, in such processes, since the solvent and the adhesive itself volatilize during the high-temperature treatment, deterioration of the working environment is also an issue. Therefore, an alternative to the adhesive tape that can bond the fluororesin to the tank body without performing high-temperature treatment is desired.

[0006] The present invention provides a wound body having little floating (tunneling) and excellent handling properties, and capable of easily bonding a fluororesin to a tank body or the like. The present invention also provides a method for manufacturing a chemical solution tank using the wound body. Further, the present invention provides a chemical solution tank to which a laminated sheet in the wound body is attached.

Means for Solving the Problems

[0007] The present disclosure 1 is a wound body having a structure in which a laminated sheet is wound around a core, wherein the outer diameter of the core is 160 mm or more and 550 mm or less, and the laminated sheet has a resin sheet containing a fluororesin and a double-sided adhesive sheet having an adhesive layer, and is a wound body. The present disclosure 2 is a wound body according to the present disclosure 1, wherein the adhesive layer in the double-sided adhesive sheet includes an adhesive layer (Y1) formed using an adhesive composition (X1) and an adhesive layer (Y2) formed using an adhesive composition (X2), and the laminated sheet has a structure in which the sheet containing the fluororesin and the adhesive layer (Y2) are adjacent to each other. The present disclosure 3 is a wound body according to the present disclosure 1 or 2, wherein the sheet containing the fluororesin includes a sheet containing polytetrafluoroethylene (PTFE). The sheet containing the fluororesin in the present disclosure 4 is a wound body of the present disclosure 1, 2, or 3 having an easily adhesive treatment layer on the surface. The easily adhesive treatment in the easily adhesive treatment layer in the present disclosure 5 is at least one selected from the group consisting of plasma irradiation, electron beam irradiation, chemical etching treatment, and easily adhesive layer bonding treatment, and it is a wound body of the present disclosure 4. The sheet containing the fluororesin in the present disclosure 6 is a wound body of the present disclosure 1, 2, 3, 4, or 5, with a thickness of 1.0 mm or more and 4.0 mm or less. In the present disclosure 7, the sheet containing the fluororesin has a surface density of 1 kg / m 2 or more and 10 kg / m 2 or less, and it is a wound body of the present disclosure 1, 2, 3, 4, 5, or 6. The total thickness of the adhesive layer in the double-sided adhesive sheet in the present disclosure 8 is 300 μm or more and 1500 μm or less, and it is a wound body of the present disclosure 1, 2, 3, 4, 5, 6, or 7. The adhesive composition (X1) in the present disclosure 9 contains a base polymer (P1), and the base polymer (P1) includes at least one selected from the group consisting of (meth)acrylic copolymers and styrene-based elastomers, and it is a wound body of the present disclosure 2. The adhesive composition (X1) in the present disclosure 10 further contains an adhesion-imparting resin (T1), and it is a wound body of the present disclosure 2 or 9. The adhesive layer (Y1) in the present disclosure 11 has a 180° peel strength against SUS at 23°C of 50 N / 25 mm or more, and it is a wound body of the present disclosure 2, 9, or 10. It is a wound body. The adhesive composition (X2) in the present disclosure 12 further contains an adhesion-imparting resin (T2), and it is a wound body of the present disclosure 2, 9, 10, or 11. The adhesion-imparting resin (T2) in the present disclosure 13 includes an adhesion-imparting resin (T2-1) having at least one structural unit (A) selected from the group consisting of the structural unit (A-1), structural unit (A-1’), structural unit (A-2), structural unit (A-2’), structural unit (A-3), structural unit (A-3’), structural unit (A-4), and structural unit (A-4’), and it is a wound body of the present disclosure 12. Disclosure 14 is a wound body of Disclosure 2, 9, 10, 11, 12, or 13, wherein the adhesive layer (Y2) has an anchor strength of 5.0 N / 25 mm or more against the sheet containing the fluororesin at 23°C. Disclosure 15 is a wound body of Disclosure 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13 or 14, wherein the double-sided adhesive sheet has a base material, and the base material 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 16 is a winding of Disclosure 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15, wherein the laminated sheet further comprises a separator. Disclosure 17 is a winding of Disclosure 16, wherein the separator is composed of at least one selected from the group consisting of polyester resin, polyolefin resin, and paper. Disclosure 18 is a wound body of Disclosure 16 or 17, wherein the separator has a release layer containing at least one release agent selected from the group consisting of polyolefin-based release agents, silicone-based release agents, and fluororesin-based release agents. Disclosure 19 is a wound body according to Disclosure 16, 17, or 18, wherein the 180° peel force at 23°C when the separator is peeled from the double-sided adhesive sheet is 150 mN / 50 mm or more and 2000 mN / 50 mm or less. Disclosure 20 is a wound body of Disclosure 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18 or 19 used for lining a tank body in a chemical tank. Disclosure 21 is a method for manufacturing a chemical tank, which includes the step of bonding a laminated sheet from a wound body of Disclosure 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 to the inside of a can body of a chemical tank. Disclosure 22 is a chemical tank in which a laminated sheet from a wound body of Disclosure 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 is attached to the inside of the tank body of the chemical tank.

[0008] [ka]

[0009] [ka]

[0010] [ka]

[0011] [ka]

[0012] In the formula, R 1 ~R 7 * 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, respectively. n and l each represent an integer between 2 and 4, and n' and l' each represent an integer between 2 and 5. m and k each represent an integer between 1 and 4, and m' and k' each represent an integer between 1 and 5. * represents a linking part. The present invention will be described in detail below.

[0013] When joining fluororesin to a can or similar object using adhesive tape, a laminated sheet is created by bonding a sheet containing fluororesin (such as PTFE) to the adhesive tape, and then this laminated sheet is bonded to the can or similar object. However, if the laminated sheet is to be created by hand by bonding the fluororesin-containing sheet to the adhesive tape at the lining site, bonding large areas is difficult and wrinkles occur. Therefore, it is necessary to use a laminating machine to bond the fluororesin-containing sheet to the adhesive tape. In addition, the fluororesin-containing sheet used as a lining sheet is very thick, and there was a problem that tunneling (lifting) occurred when using a typical winding core (outer diameter 3-6 inches). Therefore, the present inventors investigated winding a laminated sheet having a double-sided adhesive sheet and a sheet containing fluororesin, and found that it is possible to obtain a winding that has less floating (tunneling), is easy to handle, and allows the fluororesin to be easily bonded to cans and the like, thus completing the present invention. Because the winding material of the present invention has minimal tunneling, it offers excellent handling when removing the laminated sheets, allowing for easy bonding of the fluororesin to cans and the like. Furthermore, the laminated sheets in the winding material of the present invention offer excellent adhesive reliability when bonding the fluororesin to cans and the like.

[0014] The winding body of the present invention has a structure in which laminated sheets are wound around a winding core. Since the winding core has a concentric structure, the winding body of the present invention has a concentric structure. The above-mentioned core has an outer diameter with a lower limit of 160 mm and an upper limit of 550 mm. By having an outer diameter of 160 mm or more, the occurrence of tunneling in the wound laminated sheet can be suppressed, and the resulting wound body will have less tunneling and be easier to handle. By having an outer diameter of 550 mm or less, the manufacturing of the wound body of the present invention can be easily carried out. The preferred lower limit of the outer diameter of the above-mentioned core is 220 mm, the preferred upper limit is 350 mm, the more preferred lower limit is 250 mm, and the more preferred upper limit is 280 mm. The "outer diameter of the winding core" mentioned above can be calculated using the following formula (1). Outer diameter of the core (mm) = {(Inner diameter of the core) + 2 × (Wall thickness of the core)} (1)

[0015] The winding core has a preferred lower limit of 140 mm and a preferred upper limit of 530 mm for its inner diameter. Having an inner diameter of 140 mm or more makes it easier to adjust the outer diameter of the winding core within the above-mentioned range, thereby further suppressing tunneling of the wound laminated sheet. Having an inner diameter of 530 mm or less makes it easier to adjust the outer diameter of the winding core within the above-mentioned range, thereby facilitating the manufacture of the winding body of the present invention. A more preferred lower limit for the inner diameter of the winding core is 200 mm, a more preferred upper limit is 330 mm, an even more preferred lower limit is 230 mm, and an even more preferred upper limit is 260 mm.

[0016] The above-mentioned core has a preferred lower limit of 3 mm and a preferred upper limit of 20 mm in wall thickness. Having a wall thickness of 3 mm or more makes it easier to adjust the outer diameter of the core within the above-mentioned range, thereby further suppressing tunneling of the wound laminated sheet. Furthermore, the core maintains adequate strength and can withstand the weight applied during winding of the laminated sheet. Having a wall thickness of 20 mm or less makes it easier to adjust the outer diameter of the core within the above-mentioned range, thereby facilitating the manufacture of the wound body of the present invention. A more preferred lower limit for the wall thickness is 4 mm, a more preferred upper limit is 18 mm, an even more preferred lower limit is 5 mm, and an even more preferred upper limit is 15 mm.

[0017] The materials that make up the core mentioned above include paper, plastic, and the like. Examples of the above-mentioned types of paper include recycled paper, kraft paper, and cardboard. Furthermore, the core material may be made by impregnating the aforementioned types of paper with phenolic resin, epoxy resin, glass fiber, carbon fiber, etc. Examples of the above-mentioned plastics include polyethylene, polypropylene, polystyrene, acrylonitrile-butadiene-styrene copolymer (ABS resin), phenolic resin, epoxy resin, etc. Furthermore, as the material constituting the core, materials such as those impregnated with glass fibers, carbon fibers, etc., may be used.

[0018] The laminated sheet described above comprises a resin sheet containing fluororesin and a double-sided adhesive sheet having an adhesive layer.

[0019] Examples of sheets containing the above-mentioned fluororesin include sheets containing polytetrafluoroethylene (PTFE), sheets containing perfluoroalkoxyalkane (PFA), sheets containing perfluoroethylenepropene copolymer (FEP), sheets containing ethylenetetrafluoroethylene copolymer (ETFE), sheets containing polyvinylidene fluoride (PVDF), sheets containing polyvinyl fluoride (PVF), sheets containing polychlorotrifluoroethylene (PCTFE), and sheets containing ethylenechlorotrifluoroethylene copolymer (ECTFE). Among these, it is preferable that the above-mentioned fluororesin-containing sheets include sheets containing PTFE due to their excellent heat resistance and chemical resistance. The sheet containing the above-mentioned fluororesin may be a single layer or a multi-layered sheet of two or more layers.

[0020] The sheet containing the above-mentioned fluororesin preferably has an easy-adhesion treatment layer on its surface. By having an easy-adhesion treatment layer on its surface, the laminated sheet exhibits excellent adhesion between the adhesive layer (Y2) and the sheet containing the fluororesin, enabling the fluororesin to be firmly bonded to the tank body of the chemical tank.

[0021] From the viewpoint of further improving the adhesion between the adhesive layer (Y2) and the sheet containing the fluororesin, the easy-adhesion treatment in the easy-adhesion treatment layer preferably includes at least one treatment selected from the group consisting of plasma irradiation, electron beam irradiation, chemical etching, and easy-adhesion layer bonding treatment.

[0022] Examples of the above-mentioned chemical etching treatments include sodium etching.

[0023] Examples of the above-mentioned easy-adhesion layer bonding treatment include an easy-adhesion layer bonding treatment using a sheet containing fluororesin, and specific examples of the easy-adhesion layer bonding treatment using a sheet containing fluororesin include glass backing treatment and carbon cloth backing treatment. The glass backing treatment or the carbon cloth backing treatment can be carried out, for example, by laminating a sheet containing another fluororesin, a glass cloth or a carbon cloth in this order on one surface of a sheet containing a fluororesin and pressing them in a high-temperature environment. In the easy adhesion layer bonding treatment using the sheet containing the fluororesin, as the sheet containing the fluororesin, the sheet containing the fluororesin described above can be used, but it is preferable to use a sheet containing a thermoplastic fluororesin.

[0024] The thickness of the resin sheet containing the fluororesin preferably has a lower limit of 1.0 mm and an upper limit of 4.0 mm. When the thickness of the resin sheet containing the fluororesin is 1.0 mm or more, the chemical resistance is further improved. When the thickness of the resin sheet containing the fluororesin is 4.0 mm or less, the occurrence of tunneling can be suppressed when winding the laminated sheet, and the handling property of the wound body of the present invention is further improved. A more preferable lower limit of the thickness of the resin sheet containing the fluororesin is 1.5 mm, and a more preferable upper limit is 3.5 mm.

[0025] The surface density of the resin sheet containing the fluororesin preferably has a lower limit of 1 kg / m 2 and an upper limit of 10 kg / m 2 When the surface density of the resin sheet containing the fluororesin is 1 kg / m 2 or more, the chemical resistance is further improved. When the surface density of the resin sheet containing the fluororesin is 10 kg / m 2 or less, the occurrence of tunneling can be suppressed when winding the laminated sheet, and the handling property of the wound body of the present invention is further improved. A more preferable lower limit of the surface density of the resin sheet containing the fluororesin is 2 kg / m 2 and a more preferable upper limit is 8 kg / m 2 The laminated sheet has a double-sided adhesive sheet. [[ID=​​​The above-mentioned double-sided adhesive sheet has an adhesive layer. The adhesive layer of the above-mentioned double-sided adhesive sheet may be one layer or two or more layers. The total thickness of the adhesive layer of the above double-sided adhesive sheet has a preferred lower limit of 300 μm and a preferred upper limit of 1500 μm. A total thickness of 300 μm or more of the adhesive layer of the above double-sided adhesive sheet results in excellent adhesive strength. A total thickness of 1500 μm or less of the adhesive layer of the above double-sided adhesive sheet reduces the manufacturing cost of the laminated sheet. A more preferred lower limit of 350 μm, a more preferred upper limit of 1200 μm, an even more preferred lower limit of 400 μm, and an even more preferred upper limit of 1000 μm.

[0027] Preferably, the adhesive layer in the above-mentioned double-sided adhesive sheet includes an adhesive layer (Y1) formed using an adhesive composition (X1) and an adhesive layer (Y2) formed using an adhesive composition (X2). By including the adhesive layer (Y1) and the adhesive layer (Y2) in the above-mentioned double-sided adhesive sheet, it becomes possible to select an adhesive suitable for bonding to a sheet containing fluororesin and an adherend such as a can, resulting in excellent adhesive reliability when bonding the fluororesin and the can.

[0028] In this specification, if the adhesive layer of the double-sided adhesive sheet includes the adhesive layer (Y1) and the adhesive layer (Y2), the double-sided adhesive sheet shall have the adhesive layer (Y1) on the adherend side and the adhesive layer (Y2) on the sheet side containing the fluororesin. The laminated sheet preferably has a structure in which the sheet containing the fluororesin and the adhesive layer (Y2) are adjacent to each other. By having a structure in which the sheet containing the fluororesin and the adhesive layer (Y2) are adjacent to each other, delamination between the fluororesin-containing sheet and the adhesive layer is further suppressed.

[0029] From the viewpoint of ease of bonding, the adhesive layer (Y1) is preferably a low-tack adhesive layer. Since the adhesive layer (Y1) is a low-tack adhesive layer, stickiness of the adhesive layer (Y1) can be suppressed, and the resulting double-sided adhesive sheet will have superior bonding workability.

[0030] The preferred lower limit of the probe tack value (hereinafter also referred to as "the probe tack value of the adhesive layer (Y1) at 23°C") measured under the conditions of 23°C, applied pressure of 98 gf, applied pressure of 100 mm / sec, applied pressure for 10 seconds, and pulled-away speed of 5 mm / sec is 20 N / 5 mmφ. A probe tack value of the adhesive layer (Y1) at 23°C of 20 N / 5 mmφ or higher provides the adhesive layer (Y1) with appropriate adhesive strength, making it easier to adjust the application position of the double-sided adhesive sheet, thus improving the workability of the bonding process. A more preferred lower limit of the probe tack value of the adhesive layer (Y1) at 23°C is 22 N / 5 mmφ. Furthermore, the preferred upper limit of the probe tack value of the adhesive layer (Y1) at 23°C is 25N / 5mmφ. By having a probe tack value of the adhesive layer (Y1) at 23°C of 25N / 5mmφ or less, the stickiness of the adhesive layer (Y1) can be suppressed, and the double-sided adhesive sheet will have superior bonding workability. The more preferred upper limit of the probe tack value of the adhesive layer (Y1) at 23°C is 23N / 5mmφ. The probe tack value of the adhesive layer (Y1) at 23°C can be measured by a probe tack test in accordance with JIS Z 3284. Specifically, for example, a test specimen can be prepared by cutting the above-mentioned double-sided adhesive sheet to a size of 30 mm in width and 30 mm in length. The probe tack test can then be performed on the adhesive layer (Y1) of the prepared test specimen using a probe tack tester (RHESCA, "TAC-2," etc.) under the following conditions: 23°C, pressurized pressure of 98 gf, pressurization speed of 100 mm / sec, pressurization time of 10 seconds, and release speed of 5 mm / sec. Furthermore, in this specification, the term "adhesion" refers not only to a permanent bonding phenomenon but also to a temporary bonding phenomenon called "tackiness."

[0031] Methods for adjusting the probe tack value of the adhesive layer (Y1) at 23°C include changing the composition and content ratio of the base polymer (P1) and the tackifying resin (T1) described later, and changing the thickness of the adhesive layer (Y1).

[0032] The adhesive layer (Y1) preferably contains a base polymer (P1). The base polymer (P1) described above preferably contains at least one selected from the group consisting of (meth)acrylic copolymer, styrene elastomer, ethylene-vinyl acetate copolymer, chloroprene rubber, nitrile rubber, polyurethane resin, polyamide resin, polyolefin resin, polyester resin, epoxy resin, and silicone resin. In particular, from the viewpoint of making it easier to adjust the probe tack value of the adhesive layer (Y1) at 23°C and from the viewpoint of improving the heat resistance of the adhesive layer (Y1), it is preferable to include at least one selected from the group consisting of (meth)acrylic copolymer and styrene elastomer. Furthermore, from the viewpoint of suppressing contamination of the adherend, it is preferable that the base polymer (P1) is a base polymer other than silicone resin. In this specification, the term "base polymer" refers to a polymer that accounts for 50% by mass or more of the polymers with a weight-average molecular weight of 50,000 or more contained in the adhesive composition. Furthermore, in this specification, "(meth)acrylic" means acrylic or methacrylic.

[0033] The above (meth)acrylic copolymer preferably has constituent units derived from alkyl (meth)acrylate. The alkyl (meth)acrylate described above preferably includes an alkyl (meth)acrylate having an alkyl group with 4 to 12 carbon atoms at its ester terminus. That is, the (meth)acrylic copolymer preferably has structural units derived from alkyl (meth)acrylate having an alkyl group with 4 to 12 carbon atoms at its ester terminus. By having structural units derived from alkyl (meth)acrylate having an alkyl group with 4 to 12 carbon atoms at its ester terminus, the glass transition temperature (Tg) of the (meth)acrylic copolymer is further reduced. As a result, the flexibility of the adhesive layer (Y1) is further improved, and the workability of the resulting double-sided adhesive sheet is further improved. In addition, the adhesive strength of the adhesive layer (Y1) to the fluororesin is also further improved. In this specification, "(meth)acrylate" means acrylate or methacrylate. Furthermore, in this specification, the term "alkyl (meth)acrylate having an alkyl group at the ester terminus" means a (meth)acrylate in which an alkyl group is bonded to the oxygen atom of the ester bond.

[0034] Examples of alkyl (meth)acrylates having an alkyl group with 4 to 12 carbon atoms at the ester end 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, and lauryl (meth)acrylate. In particular, since the resulting adhesive sheet has superior adhesion (especially to fluororesins), it is preferable that the alkyl (meth)acrylate having an alkyl group with 4 to 12 carbon atoms at the ester end includes alkyl (meth)acrylate having an alkyl group with 6 to 8 carbon atoms at the ester end. The alkyl (meth)acrylates having an alkyl group with 4 to 12 carbon atoms at the ester terminus may be used alone or in combination of two or more types.

[0035] The preferred lower limit for the content of constituent units derived from alkyl (meth)acrylate having an alkyl group with 4 to 12 carbon atoms at its ester terminus in the above (meth)acrylic copolymer is 50% by mass. When the content of constituent units derived from alkyl (meth)acrylate having an alkyl group with 4 to 12 carbon atoms at its ester terminus is 50% by mass or more, the glass transition temperature (Tg) of the above (meth)acrylic copolymer is further reduced, and as a result the flexibility of the adhesive layer (Y1) is further improved, thus improving the workability of the resulting double-sided adhesive sheet when bonded. In addition, the adhesive strength of the adhesive layer (Y1) to the fluororesin is also further improved. A more preferred lower limit for the content of constituent units derived from alkyl (meth)acrylate having an alkyl group with 4 to 12 carbon atoms at its ester terminus is 90% by mass, and an even more preferred lower limit is 95% by mass. In particular, the preferred lower limit for the content of constituent units derived from alkyl (meth)acrylate having an alkyl group with 6 to 8 carbon atoms at its ester terminus in the above (meth)acrylic copolymer is 50% by mass, a more preferred lower limit is 85% by mass, and an even more preferred lower limit is 90% by mass. Furthermore, from the viewpoint of further improving the bulk cohesive force of the adhesive layer (Y1), the preferred upper limit for the content of constituent units derived from alkyl (meth)acrylate having an alkyl group with 4 to 12 carbon atoms at the ester end is 99.5% by mass, and the more preferred upper limit is 99% by mass.

[0036] The alkyl (meth)acrylate described above may include other alkyl (meth)acrylates other than the alkyl (meth)acrylate having an alkyl group with 4 to 12 carbon atoms at its ester terminus. 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, ester of 5,7,7-trimethyl-2-(1,3,3-trimethylbutyl)octanol-1 and (meth)acrylic acid, ester of an alcohol with a total of 18 carbon atoms having 1 or 2 methyl groups in a linear main chain and (meth)acrylic acid, behenyl (meth)acrylate, arachidyl (meth)acrylate, and the like. The above-mentioned other alkyl (meth)acrylates may be used individually or in combination of two or more types.

[0037] The (meth)acrylic copolymer preferably further contains structural units derived from a polar functional group-containing monomer. The presence of structural units derived from a polar functional group-containing monomer in the (meth)acrylic copolymer increases the bulk cohesive strength of the adhesive layer (Y1), resulting in a double-sided adhesive sheet with superior adhesion.

[0038] The above polar functional group is reactive, such as through crosslinking reactions, and preferably at least one selected from the group consisting of carboxyl groups, hydroxyl groups, amino groups, and epoxy groups. In particular, one selected from the group consisting of carboxyl groups and hydroxyl groups is more preferred because it can contribute to improving the adhesive strength of the resulting double-sided adhesive sheet. That is, it is preferable that the above (meth)acrylic copolymer has at least one structural unit selected from the group consisting of structural units derived from polar functional group-containing monomers (carboxyl group-containing monomers) having a carboxyl group as the above polar functional group, and structural units derived from polar functional group-containing monomers (hydroxyl group-containing monomers) having a hydroxyl group as the above polar functional group. Examples of the above-mentioned carboxyl group-containing monomers include (meth)acrylic acid. Examples of the hydroxyl group-containing monomers mentioned above include 4-hydroxybutyl (meth)acrylate and 2-hydroxyethyl (meth)acrylate. Examples of polar functional group-containing monomers (epoxy group-containing monomers) having an epoxy group as the polar functional group include glycidyl (meth)acrylate. The above-mentioned monomers containing polar functional groups may be used individually or in combination of two or more types.

[0039] In the above (meth)acrylic copolymer, the preferred lower limit for the content of constituent units derived from the carboxyl group-containing monomer is 0.01% by mass, and the preferred upper limit is 3.0% by mass. By having the content of constituent units derived from the carboxyl group-containing monomer within this range, the cohesive force of the bulk of the adhesive layer (Y1) can be appropriately adjusted, resulting in a double-sided adhesive sheet with superior adhesion. A more preferred lower limit for the content of constituent units derived from the carboxyl group-containing monomer is 0.05% by mass, and a more preferred upper limit is 2.0% by mass.

[0040] In the above (meth)acrylic copolymer, the preferred lower limit for the content of constituent units derived from the above hydroxyl group-containing monomer is 0.01% by mass, and the preferred upper limit is 3.0% by mass. By having the content of constituent units derived from the above hydroxyl group-containing monomer within this range, the cohesive force of the bulk of the adhesive layer (Y1) can be appropriately adjusted, resulting in a double-sided adhesive sheet with superior adhesion. A more preferred lower limit for the content of constituent units derived from the above hydroxyl group-containing monomer is 0.05% by mass, and a more preferred upper limit is 2.0% by mass.

[0041] In the above (meth)acrylic copolymer, the preferred lower limit for the total content of constituent units derived from the above polar functional group-containing monomer is 0.01% by mass, and the preferred upper limit is 6.0% by mass. By having the total content of constituent units derived from the above polar functional group-containing monomer within this range, the cohesive force of the bulk of the adhesive layer (Y1) can be appropriately adjusted, resulting in a double-sided adhesive sheet with superior adhesion. A more preferred lower limit for the total content of constituent units derived from the above polar functional group-containing monomer is 0.1% by mass, and a more preferred upper limit is 3.0% by mass.

[0042] The above (meth)acrylic copolymer may optionally contain structural units derived from other copolymerizable monomers other than the alkyl (meth)acrylate and the polar functional group-containing monomer. Examples of other monomers mentioned above include benzyl (meth)acrylate, 2-butoxyethyl (meth)acrylate, 2-phenoxyethyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, and polypropylene glycol mono(meth)acrylate. In addition, other monomers that can be used include vinyl carboxylates such as vinyl acetate and various monomers commonly used in acrylic polymers such as styrene. The other monomers mentioned above may be used individually or in combination of two or more.

[0043] The preferred lower limit for the weight-average molecular weight (Mw) of the above (meth)acrylic copolymer is 50,000, and the preferred upper limit is 1,600,000. A weight-average molecular weight (Mw) of 50,000 or more improves the bulk cohesive strength of the adhesive layer (Y1), resulting in a double-sided adhesive sheet with superior adhesion. A weight-average molecular weight (Mw) of 1,600,000 or less further improves the adhesion of the adhesive layer (Y1) to the fluororesin. A more preferred lower limit for the weight-average molecular weight (Mw) of the above (meth)acrylic copolymer is 100,000, and a more preferred upper limit is 1,200,000.

[0044] The preferred lower limit for the ratio of the weight-average molecular weight (Mw) to the number-average molecular weight (Mn) of the above (meth)acrylic copolymer (molecular weight distribution (Mw / Mn)) is 1.05, and the preferred upper limit is 10.0. When the molecular weight distribution (Mw / Mn) of the above (meth)acrylic copolymer is 1.05 or higher, the adhesive layer (Y1) becomes more flexible, and the workability of laminating the resulting double-sided adhesive sheet is further improved. The resulting double-sided adhesive sheet becomes more adhesive to fluororesin. When the molecular weight distribution (Mw / Mn) of the above (meth)acrylic copolymer is 10.0 or lower, the proportion of low molecular weight components is suppressed, the bulk cohesive force of the adhesive layer (Y1) is improved, and the resulting double-sided adhesive sheet becomes more adhesive. A more preferred upper limit for the molecular weight distribution (Mw / Mn) of the above (meth)acrylic copolymer is 9.0, an even more preferred upper limit is 8.0, and an even more preferred upper limit is 7.0.

[0045] In this specification, weight-average molecular weight (Mw) and number-average molecular weight (Mn) refer to the weight-average molecular weight (Mw) and number-average molecular weight (Mn) measured in standard polystyrene equivalent as determined by gel permeation chromatography (GPC), respectively. Specifically, a (meth)acrylic copolymer is diluted 50-fold with tetrahydrofuran (THF), and the diluted solution is filtered through a filter (material: polytetrafluoroethylene, pore diameter: 0.2 μm). The obtained filtrate is supplied to a gel permeation chromatograph (Waters, "2690 Separations Module," etc.), and GPC measurement is performed under conditions of sample flow rate of 1 mL / min and column temperature of 40°C to measure the polystyrene equivalent molecular weight of the (meth)acrylic copolymer and determine the weight-average molecular weight (Mw) and number-average molecular weight (Mn). For example, a GPC KF-802.5L (Showa Denko Corporation) can be used as the column, and for example, a differential refractometer can be used as the detector. Furthermore, the molecular weight distribution (Mw / Mn) can be measured using the obtained weight-average molecular weight (Mw) and number-average molecular weight (Mn).

[0046] Methods for adjusting the weight-average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the above-mentioned (meth)acrylic copolymer to within the above range include, for example, adjusting the composition of the monomers constituting the (meth)acrylic copolymer, the polymerization method, the polymerization conditions, etc.

[0047] The preferred lower limit for the glass transition temperature (Tg) of the above (meth)acrylic copolymer is -70°C, and the preferred upper limit is -30°C. Having the glass transition temperature of the above (meth)acrylic copolymer within this range improves the lamination workability of the resulting double-sided adhesive sheet. Furthermore, the resulting double-sided adhesive sheet exhibits superior adhesion to fluororesin. A more preferred lower limit for the glass transition temperature (Tg) of the above (meth)acrylic copolymer is -60°C, and a more preferred upper limit is -40°C. In this specification, the glass transition temperature is the value obtained in the first run when measured using a differential scanning calorimeter (for example, Hitachi High-Tech Science Corporation's "SII Exstar 6000 / DSC 6220") under a nitrogen atmosphere and a heating rate of 10°C / min.

[0048] As polymerization methods for synthesizing the above-mentioned (meth)acrylic copolymer, conventionally known methods can be used in which monomers from which the above-mentioned constituent units are derived are subjected to a radical reaction in the presence of a polymerization initiator. Examples include solution polymerization (boiling point polymerization or constant temperature polymerization), emulsion polymerization, suspension polymerization, and bulk polymerization. Among these, solution polymerization is preferred because it is easy to synthesize.

[0049] When solution polymerization is used as the polymerization method described above, examples of reaction solvents include ethyl acetate, toluene, methyl ethyl ketone, methyl sulfoxide, ethanol, acetone, and diethyl ether. The above reaction solvents may be used individually or in combination of two or more types.

[0050] Examples of polymerization initiators include organic peroxides and azo compounds. Examples of the above-mentioned 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 above-mentioned azo compounds include azobisisobutyronitrile and azobiscyclohexanecarbonitride. The polymerization initiators described above may be used alone or in combination of two or more.

[0051] The styrene-based elastomer is preferably a block copolymer having a block derived from the styrene-based monomer and a block derived from a conjugated diene monomer, possessing rubber elasticity at room temperature, and having a hard segment portion and a soft segment portion. The block derived from the styrene-based monomer is the hard segment portion, and the block derived from the conjugated diene monomer is the soft segment portion.

[0052] Examples of the styrene monomers mentioned above 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 it is readily available industrially. Examples of the above-mentioned tertiary amino group-containing diphenylethylene include 1-(4-N,N-dimethylaminophenyl)-1-phenylethylene. The above-mentioned styrene monomers may be used individually or in combination of two or more types.

[0053] Examples of the above-mentioned conjugated diene monomers 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, and 2-chloro-1,3-butadiene. Among these, 1,3-butadiene and isoprene are preferred due to their high polymerization reactivity and ease of industrial availability. The above-mentioned conjugated diene monomers may be used individually or in combination of two or more types.

[0054] Furthermore, in order to improve retention and heat resistance by chemically imparting a crosslinked structure to the above-mentioned conjugated diene monomer, a copolymer of a polar functional group-containing monomer such as maleic anhydride may be used for the block derived from the above-mentioned conjugated diene monomer.

[0055] Examples of the styrene-based elastomers mentioned above include styrene-isoprene-styrene (SIS) block copolymer, styrene-butadiene-styrene (SBS) block copolymer, styrene-chloroprene-styrene block copolymer, styrene-ethylene-butylene-styrene copolymer (SEBS), styrene-ethylene-propylene-styrene copolymer (SEPS), and styrene-isobutylene-styrene copolymer (SIBS). Among these, SIS block copolymer and SBS block copolymer are preferred, and SIS block copolymer is more preferred, because the resulting double-sided adhesive sheet tends to exhibit high adhesive strength and is less likely to peel off the adherend even when immersed in an alkaline chemical solution. The above-mentioned styrene-based elastomers may be used individually or in combination of two or more types.

[0056] The styrene-based elastomer preferably includes a triblock copolymer of a block derived from the styrene-based monomer and a block derived from the conjugated diene monomer, and more preferably includes a diblock copolymer of a block derived from the styrene-based monomer and a block derived from the conjugated diene monomer, in addition to the triblock copolymer. The preferred lower limit for the content of the diblock copolymer in the styrene-based elastomer (hereinafter sometimes referred to as the "diblock ratio") is 50% by mass. When the diblock ratio is 50% by mass or higher, the adhesive strength of the adhesive layer (Y1) to the adherend is further improved, and the resulting double-sided adhesive sheet has superior adhesive properties. In addition, the flexibility of the adhesive layer (Y1) is further improved, so the adhesive strength of the adhesive layer (Y1) to the fluororesin is further improved. A more preferred lower limit for the diblock ratio is 70% by mass. Furthermore, from the viewpoint of further improving the cohesive force of the adhesive layer (Y1), the preferred upper limit of the jiblock ratio is 90% by mass. The above diblock ratio can be calculated from the peak area ratio of each copolymer measured by gel permeation chromatography (GPC).

[0057] A preferred upper limit for the content of blocks derived from the styrene monomer in the above-mentioned styrene-based elastomer (hereinafter sometimes referred to as "styrene content") is 20% by mass. When the styrene content is 20% by mass or less, the adhesive layer (Y1) does not become too hard, the adhesive strength to the adherend is further improved, and the resulting adhesive sheet has superior adhesive properties. A more preferred upper limit for the styrene content is 16% by mass. Furthermore, from the viewpoint of further improving the cohesive force of the adhesive layer (Y1), the preferred lower limit of the styrene content is 8% by mass. The above styrene content is, 1 It can be calculated from the peak area ratio of each block measured by 1H-NMR.

[0058] The preferred lower limit for the weight-average molecular weight of the above styrene-based elastomer is 50,000, and the preferred upper limit is 600,000. A weight-average molecular weight of 50,000 or more for the above styrene-based elastomer increases the bulk strength of the adhesive layer (Y1), resulting in a more adhesive sheet with superior adhesion. A weight-average molecular weight of 600,000 or less for the above styrene-based elastomer further improves the compatibility between the above styrene-based elastomer and other components. A more preferred lower limit for the weight-average molecular weight of the above styrene-based elastomer is 100,000, and a more preferred upper limit is 500,000.

[0059] Examples of commercially available ethylene-vinyl acetate copolymers include HM200 (manufactured by Cemedyne Co., Ltd.). Examples of commercially available chloroprene rubbers include 575F (manufactured by Cemedyne Co., Ltd.) and G17 (manufactured by Konishi Co., Ltd.). Examples of commercially available nitrile rubbers include 501F (manufactured by Cemedyne Co., Ltd.). Examples of commercially available polyurethane resins include SHM107-PUR (manufactured by Seedam Corporation). Examples of commercially available polyamide resins include SHM301-PAD (manufactured by Seedam Corporation). Examples of commercially available polyolefin resins include PPET1200F (manufactured by Toagosei Co., Ltd.). Examples of commercially available polyester resins include PH-413 (manufactured by Nippon Matai Co., Ltd.). Examples of commercially available epoxy resins include 1500 (manufactured by Cemedyne Co., Ltd.). Examples of commercially available silicone resins include KR-3700 (manufactured by Shin-Etsu Chemical Co., Ltd.).

[0060] The preferred lower limit for the content of the base polymer (P1) in the adhesive composition (X1) is 50% by mass, and the preferred upper limit is 99% by mass. By keeping the content of the base polymer (P1) within this range, the adhesive properties such as peel strength and holding strength of the adhesive layer (Y1) can be well-balanced. The more preferred lower limit for the content of the base polymer (P1) is 75% by mass, and the more preferred upper limit is 90% by mass.

[0061] From the viewpoint of further improving adhesive strength, the above adhesive composition (X1) preferably contains a tackifying resin (T1).

[0062] The tackifying resin (T1) preferably contains at least one tackifying resin selected from the group consisting of rosin ester resins, terpene resins, terpene phenol resins, and petroleum resins. By including at least one tackifying resin selected from the group consisting of rosin ester resins, terpene resins, terpene phenol resins, and petroleum resins in the tackifying resin (T1), the adhesive strength of the adhesive layer (Y1) can be further improved. In particular, since the adhesive strength can be further improved, it is more preferable that the tackifying resin (T1) contains at least one tackifying resin selected from the group consisting of rosin ester resins and terpene resins.

[0063] The preferred lower limit of the softening temperature of the tackifying resin (T1) is 50°C, and the preferred upper limit is 200°C. A softening temperature of 50°C or higher for the tackifying resin (T1) prevents the adhesive layer (Y1) from becoming too soft and reducing its adhesive strength. A softening temperature of 200°C or lower for the tackifying resin (T1) improves the wettability of the interface of the adhesive layer (Y1), preventing interfacial delamination. Furthermore, if the base polymer (P1) includes the (meth)acrylic copolymer, the glass transition temperature (Tg) of the (meth)acrylic copolymer is further reduced, improving the flexibility of the adhesive layer (Y1), thus improving the workability of the resulting double-sided adhesive sheet. The adhesive strength of the adhesive layer (Y1) to the fluororesin is also improved. A more preferred lower limit of the softening temperature of the tackifying resin (T1) is 70°C, and a more preferred upper limit is 150°C. Note that the softening temperature refers to the softening temperature measured according to JIS K 2207 (ring-ball method).

[0064] The preferred lower limit of the hydroxyl value of the tackifying resin (T1) is 0 mgKOH / g, and the preferred upper limit is 200 mgKOH / g. Having the hydroxyl value of the tackifying resin (T1) within this range improves the wettability of the interface of the adhesive layer (Y1), thereby suppressing interfacial delamination. A more preferred lower limit of the hydroxyl value of the tackifying resin (T1) is 30 mgKOH / g, and a more preferred upper limit is 130 mgKOH / g. The above hydroxyl value can be measured according to JIS K 1557 (phthalic anhydride method).

[0065] The rosin ester resins mentioned above are resins obtained by esterifying rosin resins mainly composed of abietic acid, disproportionated rosin resins, hydrogenated rosin resins, or dimers of resin acids such as abietic acid (polymerized rosin resins) with alcohol. Some of the hydroxyl groups of the alcohol used in esterification are not used in the esterification process and are instead contained within the resin, thereby adjusting the hydroxyl value to the range described above. Examples of such alcohols include polyhydric alcohols such as ethylene glycol, glycerin, and pentaerythritol. Examples of commercially available rosin ester resins include Pine Crystal KE-359 (manufactured by Arakawa Chemical Industries, Ltd., hydroxyl value: 40 mg KOH / g, softening temperature: 100°C).

[0066] The above-mentioned terpene resin is a resin that has structural units derived from monoterpene compounds and does not have structural units derived from aromatic compounds. Examples of commercially available terpene resins include YS Resin PX1250 (manufactured by Yasuhara Chemical Co., Ltd., hydroxyl value: 0 mg KOH / g, softening temperature: 125°C).

[0067] The above-mentioned terpene phenol resin is a resin having structural units derived from monoterpene compounds and structural units derived from phenol compounds. In this specification, the term "phenol compound" in the terpene phenol resin refers to a compound that contains an aromatic ring structure having only one phenolic hydroxyl group and does not contain an aromatic ring structure having two or more phenolic hydroxyl groups. The constituent units derived from the phenol compound in the terpene phenol resin do not include the constituent unit (A-1) and the constituent unit (A-1') in the tackifying resin (T2-1) described later. Examples of commercially available terpene phenol resins include YS Polystar G150 (manufactured by Yasuhara Chemical Co., Ltd., hydroxyl value: 120 mg KOH / g, softening temperature: 150°C).

[0068] Examples of commercially available petroleum-based resins include Alcon P-140 (manufactured by Arakawa Chemical Industries, Ltd., hydroxyl value: 0 mg KOH / g, softening temperature: 140°C).

[0069] The preferred lower limit for the content of the tackifying resin (T1) per 100 parts by mass of the base polymer (P1) is 10 parts by mass, and the preferred upper limit is 100 parts by mass. A content of 10 parts by mass or more of the tackifying resin (T1) can further improve the adhesive strength of the adhesive layer (Y1). A content of 100 parts by mass or less of the tackifying resin (T1) can prevent the adhesive layer (Y1) from becoming too hard and reducing its adhesive strength. A more preferred lower limit for the content of the tackifying resin (T1) is 20 parts by mass, and a more preferred upper limit is 80 parts by mass.

[0070] The above adhesive composition (X1) preferably contains a crosslinking agent. In particular, if the base polymer (P1) contains the (meth)acrylic copolymer, the adhesive composition (X1) preferably contains a crosslinking agent. By containing a crosslinking agent in the adhesive layer (Y1), the (meth)acrylic copolymer forms a crosslinked structure through chemical crosslinking, resulting in a double-sided adhesive sheet with superior adhesion. Furthermore, from the viewpoint of storage stability and other factors, the crosslinking agent may be added to the adhesive composition (X1) immediately before forming the adhesive layer (Y1).

[0071] Examples of the crosslinking agents include isocyanate-based crosslinking agents, aziridine-based crosslinking agents, epoxy-based crosslinking agents, and metal chelate-type crosslinking agents. In particular, it is preferable that the crosslinking agent includes at least one selected from the group consisting of isocyanate-based crosslinking agents and epoxy-based crosslinking agents, as this enables appropriate chemical crosslinking of the (meth)acrylic copolymer and further improves the adhesive strength of the adhesive layer (Y1).

[0072] Examples of commercially available isocyanate-based crosslinking agents include Coronate L-45 (manufactured by Tosoh Corporation), Takenate 500 (manufactured by Mitsui Chemicals), and Desmodule L-75 (manufactured by Covestro Corporation). Examples of commercially available epoxy crosslinking agents include E-5C (manufactured by Soken Chemical Co., Ltd.) and E-5XM (manufactured by Soken Chemical Co., Ltd.).

[0073] The preferred lower limit for the content of the crosslinking agent in the above adhesive composition (X1) per 100 parts by mass of the (meth)acrylic copolymer is 0.1 parts by mass, and the preferred upper limit is 10 parts by mass. Having the crosslinking agent content within this range allows for appropriate chemical crosslinking of the (meth)acrylic copolymer, further improving the adhesive strength of the adhesive layer (Y1). A more preferred lower limit for the crosslinking agent content is 0.5 parts by mass, and a more preferred upper limit is 5.0 parts by mass.

[0074] From the viewpoint of further improving adhesive strength, the above adhesive composition (X1) preferably contains a silane coupling agent. Examples of the silane coupling agents mentioned above include vinyltrimethoxysilane, vinyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, and 3-aminopropyltriethoxysilane. The silane coupling agents described above may be used individually or in combination of two or more types.

[0075] The preferred lower limit for the content of the silane coupling agent per 100 parts by mass of the base polymer (P1) is 0.1 parts by mass, and the preferred upper limit is 3.0 parts by mass. A content of 0.1 parts by mass or more of the silane coupling agent can further improve the adhesive strength of the adhesive layer (Y1). A content of 3.0 parts by mass or less of the silane coupling agent can suppress bleed-out of the silane coupling agent. A more preferred lower limit for the content of the silane coupling agent is 0.5 parts by mass, and a more preferred upper limit is 2.0 parts by mass.

[0076] The above adhesive composition (X1) may optionally contain conventionally known fine particles and additives such as inorganic fine particles, conductive fine particles, antioxidants, foaming agents, organic fillers, and inorganic fillers.

[0077] The preferred lower limit for the gel fraction of the adhesive layer (Y1) is 15% by mass, and the preferred upper limit is 60% by mass. When the gel fraction of the adhesive layer (Y1) is 15% by mass or more, the bulk strength of the adhesive layer (Y1) is increased, and the resulting double-sided adhesive sheet has superior adhesion. When the gel fraction of the adhesive layer (Y1) is 60% by mass or less, the flexibility of the adhesive layer (Y1) is further improved, and the adhesive strength of the adhesive layer (Y1) is further improved. The more preferred lower limit for the gel fraction of the adhesive layer (Y1) is 25% by mass, and the more preferred upper limit is 50% by mass. The gel fraction of the adhesive layer (Y1) can be measured by the following methods, etc. Specifically, a test specimen is prepared by cutting a laminate having the adhesive layer (Y1) and a substrate, or the adhesive layer (Y1) alone, into a planar rectangular shape with a width of 20 mm and a length of 40 mm. 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. If the base polymer (P1) is a (meth)acrylic copolymer, ethyl acetate can be used as the organic solvent; if the base polymer (P1) is a styrene-based elastomer or silicone resin, toluene can be used. The mass of the dried test specimen is measured, and the gel fraction is calculated using the following formula (2). Note that the test specimen is not laminated with a release film to protect the adhesive layer (Y1). If the test specimen does not have a substrate, W0 is calculated as 0. Gel fraction (mass %) = 100 × (W2 - W0) / (W1 - W0) (2) (W0: Mass of the substrate, W1: Mass of the test specimen before immersion, W2: Mass of the test specimen after immersion and drying)

[0078] The gel fraction of the adhesive layer (Y1) can be adjusted to within the above range by, for example, changing the type or constituent units of the base polymer (P1) (for example, changing the type of monomer constituting the (meth)acrylic copolymer), adjusting the content ratio of the base polymer (P1), adjusting the weight-average molecular weight of the base polymer (P1), adjusting the type and content of the crosslinking agent, etc.

[0079] The adhesive layer (Y1) described above has a preferred lower limit of 50 N / 25 mm for its 180° peel force against SUS at 23°C. A 180° peel force of 50 N / 25 mm or higher for the adhesive layer (Y1) against SUS at 23°C results in superior adhesive strength, and therefore the resulting adhesive sheet exhibits higher adhesion. A more preferred lower limit for the 180° peel force of the adhesive layer (Y1) against SUS at 23°C is 75 N / 25 mm, and an even more preferred lower limit is 100 N / 25 mm. Furthermore, there is no specific upper limit to the 180° peel force of the adhesive layer (Y1) against SUS at 23°C, but the practical upper limit is 500 N / 25 mm. The 180° peel force on the adhesive layer (Y1) at 23°C relative to SUS can be measured by the following method. Specifically, the laminated sheet is cut to a size of 25 mm in width and 100 mm in length, and the separator is removed as necessary. Then, the adhesive layer (Y1) side is placed on a SUS plate (SUS304 plate that has been washed with ethanol and then wiped dry), and the laminate is pressed together by applying pressure at 0.1 MPa for 10 minutes in an environment of 120°C to create a laminate. A 180° peel test is performed on the obtained laminate using a tensile testing machine (such as "Autograph" manufactured by Shimadzu Corporation) in accordance with JIS Z 0237, under conditions of 23°C, 50% RH, and a peeling speed of 300 mm / min. By peeling the adhesive sheet from the SUS plate, the 180° peel force of the adhesive layer (Y1) side relative to SUS at 23°C can be measured.

[0080] Methods for adjusting the 180° peel force of the adhesive layer (Y1) to SUS at 23°C include, for example, changing the type or constituent units of the base polymer (P1) (for example, changing the copolymerization ratio or monomer composition of the base polymer (P1)), adjusting the type or content of the tackifying resin (T1), changing the thickness of the adhesive layer (Y1), or changing the substrate.

[0081] The preferred lower limit for the thickness of the adhesive layer (Y1) is 50 μm, and the preferred upper limit is 1000 μm. By having the thickness of the adhesive layer (Y1) within this range, the adhesive layer (Y1) will have sufficient adhesive strength. A more preferred lower limit for the thickness of the adhesive layer (Y1) is 100 μm, and a more preferred upper limit is 700 μm.

[0082] The adhesive layer (Y2) is formed using the adhesive composition (X2). The above adhesive composition (X2) preferably contains a base polymer (P2). Examples of the base polymer (P2) include (meth)acrylic copolymers, styrene elastomers, and silicone resins. In particular, the base polymer (P2) preferably contains at least one selected from the group consisting of (meth)acrylic copolymers and styrene elastomers, in order to allow for a wide range of designs for the adhesive layer (Y2) and for the adhesive layer (Y2) to exhibit strong adhesive strength. Furthermore, from the viewpoint of suppressing contamination of the adherend, the base polymer (P2) is preferably a base polymer other than a silicone resin.

[0083] Examples of the (meth)acrylic copolymer, styrene elastomer, and silicone resin in the above-mentioned base polymer (P2) are the same as those in the above-mentioned base polymer (P1).

[0084] The preferred lower limit and preferred upper limit of the content of the base polymer (P2) in the adhesive composition (X2) are 30% by mass and 99.5% by mass, respectively. Having the base polymer (P2) content within this range further improves the adhesion of the adhesive layer (Y2) to the fluororesin. A more preferred lower limit for the base polymer (P2) content is 40% by mass, a more preferred upper limit is 99% by mass, an even more preferred lower limit is 50% by mass, and an even more preferred upper limit is 95% by mass.

[0085] The above adhesive composition (X2) preferably contains a tackifying resin (T2). Preferably, the tackifying resin (T2) contains a tackifying resin (T2-1) having at least one constituent unit (A) selected from the group consisting of constituent units (A-1), (A-1'), (A-2), (A-2'), (A-3), (A-3'), (A-4), and (A-4') represented by the above formula. By including the tackifying resin (T2-1) in the adhesive composition (X2), the adhesive layer (Y2) can exhibit higher adhesive strength, particularly to low-polarity adherends (e.g., fluororesins). In particular, the interaction with the adherend can be greatly improved, and the adhesive strength to the adherend can be further enhanced, so it is preferable that the above-mentioned structural unit (A) is at least one selected from the group consisting of structural unit (A-1), structural unit (A-1'), structural unit (A-2), structural unit (A-2'), structural unit (A-3), and structural unit (A-3'), and it is more preferable that it is at least one selected from the group consisting of structural unit (A-1) and structural unit (A-1'). By the above-mentioned structural unit (A) being at least one selected from the group consisting of structural unit (A-1) and structural unit (A-1'), the interaction with the adherend can be further greatly improved. Furthermore, since monomers containing bio-derived materials, which will be described later, can be easily used as monomers constituting the above-mentioned structural unit (A-1) and structural unit (A-1'), it is preferable from the viewpoint of saving petroleum resources. Furthermore, if the base polymer (P2) contains the (meth)acrylic copolymer, the tackifying resin (T2-1) has appropriate polarity, which further improves its compatibility with the (meth)acrylic copolymer.

[0086] The tackifying resin (T2-1) may have the above-mentioned structural unit (A) in the side chain, or in the main chain skeleton or at the ends of the main chain skeleton. In particular, it is preferable that the tackifying resin (T2-1) has the above-mentioned structural unit (A) in the main chain skeleton or at the ends of the main chain skeleton, as this allows it to have suitable physical properties required as a tackifying resin.

[0087] In the above constituent unit (A), R 1 ~R 7 Each of these 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. Examples of the above-mentioned aliphatic hydrocarbon group include linear, branched, or cyclic alkyl groups having 1 to 20 carbon atoms. Examples of the above-mentioned aromatic hydrocarbon groups include substituted or unsubstituted aryl groups having 6 to 20 carbon atoms. Examples of the above polar functional groups include amino groups, carboxyl groups, carbonyl groups, alkoxy groups, hydroxyl groups, nitrile groups, and nitro groups. 1 As for R, polar functional groups other than hydroxyl groups can be used, 2 For polar functional groups other than carboxyl groups, R 3 OR 4 Polar functional groups other than those represented by R can be used. 5 As for NR 6 R 7 Polar functional groups other than those represented by can be used. As an aliphatic hydrocarbon group having the above polar functional group, for example, a group in which one or more hydrogens in the aliphatic hydrocarbon group are substituted with the above polar functional group can be used. As an aromatic hydrocarbon group having the above polar functional group, for example, a group in which one or more hydrogens in the aromatic hydrocarbon group are substituted with the above polar functional group can be used.

[0088] Furthermore, in the above-mentioned tackifying resin (T2-1), multiple R components are included in one constituent unit (A-1). 1 These may be the same or different. Also, multiple Rs contained in different constituent units (A-1) 1 These may be the same or different. Similarly, multiple Rs contained within a single constituent unit (A-1') 1 These may be the same or different. Also, multiple Rs contained in different constituent units (A-1')1 They may be the same or they may be different.

[0089] Similarly, multiple R units contained within a single constituent unit (A-2) 2 These may be the same or different. Also, multiple Rs contained in different constituent units (A-2) 2 These may be the same or different. Similarly, multiple Rs contained within a single constituent unit (A-2') 2 These may be the same or different. Also, multiple Rs contained in different constituent units (A-2') 2 They may be the same or they may be different.

[0090] Similarly, multiple Rs contained within a single constituent unit (A-3) 3 These may be the same or different. Also, multiple Rs contained in different constituent units (A-3) 3 These may be the same or different. Similarly, multiple Rs contained within a single constituent unit (A-3') 3 These may be the same or different. Also, multiple Rs contained in different constituent units (A-3') 3 They may be the same or they may be different.

[0091] Similarly, multiple Rs contained within a single constituent unit (A-3) 4 These may be the same or different. Also, multiple Rs contained in different constituent units (A-3) 4 These may be the same or different. Similarly, multiple Rs contained within a single constituent unit (A-3') 4 These may be the same or different. Also, multiple Rs contained in different constituent units (A-3') 4 They may be the same or they may be different.

[0092] Similarly, multiple Rs contained within a single constituent unit (A-4)5 These may be the same or different. Also, multiple Rs contained in different constituent units (A-4) 5 These may be the same or different. Similarly, multiple Rs contained within a single constituent unit (A-4') 5 These may be the same or different. Also, multiple Rs contained in different constituent units (A-4') 5 They may be the same or they may be different.

[0093] Similarly, multiple Rs contained within a single constituent unit (A-4) 6 and R 7 These may be the same or different. Also, multiple Rs contained in different constituent units (A-4) 6 and R 7 These may be the same or different. Similarly, multiple Rs contained within a single constituent unit (A-4') 6 and R 7 These may be the same or different. Also, multiple Rs contained in different constituent units (A-4') 6 and R 7 They may be the same or they may be different.

[0094] In the above-mentioned structural unit (A), n and l are integers between 2 and 4, and n' and l' are integers between 2 and 5, but from the viewpoint of ease of obtaining raw materials, it is preferable that n, l, n', and l' are 2 or 3, and it is more preferable that n, l, n', and l' are 3, as this can further improve the adhesive strength of the adhesive layer (Y2).

[0095] In the above-mentioned structural unit (A), m and k are integers between 1 and 4, and m' and k' are integers between 1 and 5, but from the viewpoint of ease of obtaining raw materials, it is preferable that m, k, m', and k' are 1, 2, or 3, and it is more preferable that m, k, m', and k' are 1, as this can further improve the adhesive strength of the adhesive layer (Y2).

[0096] More specifically, the above-mentioned constituent units (A-1) and (A-1') include, for example, a constituent unit derived from dihydroxybenzene or its derivatives (when n and n' are 2), a constituent unit derived from trihydroxybenzene or its derivatives (when n and n' are 3), and so on. These constituent units may be used individually, or two or more may be used in combination.

[0097] Examples of the above-mentioned dihydroxybenzene or its derivatives 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, benzyldihydroxyphenyl ketone, dihydroxybenzamide, dihydroxymethoxybenzene, dihydroxybenzyl alcohol, dihydroxyphenylethanol, dihydroxyphenyl glycol, dihydroxyphenylacetonitrile, and dihydroxynitrobenzene. Among these, pyrocatechol is preferred because it has low steric hindrance and readily interacts with the adherend. The above-mentioned dihydroxybenzene or its derivatives may be used alone or in combination of two or more types.

[0098] Examples of the above-mentioned trihydroxybenzene or its derivatives 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 low steric hindrance and readily interacts with the adherend. The above-mentioned trihydroxybenzene or its derivatives may be used alone or in combination of two or more types.

[0099] More specifically, the above-mentioned constituent units (A-2) and (A-2') include constituent 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'-stilbendicarboxylic acid, and their derivatives. Among these, the constituent unit derived from 4-vinylbenzoic acid is preferred because it has less steric hindrance and readily interacts with the adherend. These constituent units may be used individually, or two or more may be used in combination.

[0100] More specifically, the above-mentioned constituent units (A-3) and (A-3') include, for example, constituent units derived from dialkoxybenzene or its derivatives (when l and l' are 2), and constituent units derived from trialkoxybenzene or its derivatives (when l and l' are 3).

[0101] Examples of the above-mentioned dialkoxybenzene or its derivatives include 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, and 1,4-dimethoxybenzene. The above-mentioned dialkoxybenzene or its derivatives may be used alone or in combination of two or more types.

[0102] Examples of trialkoxybenzene or its derivatives 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 low steric hindrance and readily interacts with the adherend. The above-mentioned trialkoxybenzene or its derivatives may be used alone or in combination of two or more types.

[0103] More specifically, the above-mentioned constituent units (A-4) and (A-4') include, for example, constituent units derived from aminobenzene or its derivatives (when k and k' are 1). Examples of the above-mentioned aminobenzene or its derivatives include aniline, methylaniline, ethylaniline, dimethylaniline, and diethylaniline. The above-mentioned aminobenzene or its derivatives may be used alone or in combination of two or more types.

[0104] The above-mentioned component (A) may consist solely of petroleum-derived materials, but it is preferable that it includes bio-derived materials. The depletion of petroleum resources and the emission of carbon dioxide from the combustion of petroleum-derived products are serious concerns. Therefore, attempts are being made to conserve petroleum resources by using bio-derived materials instead of petroleum-derived materials. It is preferable from the standpoint of conserving petroleum resources if the above-mentioned component (A) includes bio-derived materials. Furthermore, if the above-mentioned component (A) includes bio-derived materials, since bio-derived materials are originally produced by absorbing carbon dioxide from the atmosphere, it is thought that burning them will not increase the total amount of carbon dioxide in the atmosphere, which is also preferable from the standpoint of reducing carbon dioxide emissions. Examples of monomers constituting the above-mentioned constituent unit (A), which includes bio-derived materials, 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, trihydroxynitrobenzene, and the like.

[0105] The preferred lower limit of the content (on a molar basis) of the constituent unit (A) in the tackifying resin (T2-1) is 1 mol%, and the preferred upper limit is 60 mol%. By having a content of 1 mol% or more of the constituent unit (A), the adhesive strength of the adhesive layer (Y2) can be further improved by blending the tackifying resin (T2-1) into the adhesive composition (X2). By having a content of 60 mol% or less of the constituent unit (A), the tackifying resin (T2-1) will have the preferred physical properties required for a tackifying resin. A more preferred lower limit of the content of the constituent 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 preferred lower limit (by mass) of the content ratio (by mass) of the constituent unit (A) in the tackifying resin (T2-1) is 0.9% by mass, and the preferred upper limit is 60% by mass. By having a content ratio of 0.9% by mass or more of the constituent unit (A), the adhesive strength of the adhesive layer (Y2) can be further improved by blending the tackifying resin (T2-1) into the adhesive composition (X2). By having a content ratio of 60% by mass or less of the constituent unit (A), the tackifying resin (T2-1) will have the preferred physical properties required as a tackifying resin. A more preferred lower limit for the content ratio of the constituent unit (A) is 5% by mass, a more preferred upper limit is 50% by mass, an even more preferred lower limit is 10% by mass, and an even more preferred upper limit is 30% by mass.

[0106] Preferably, the tackifying resin (T2-1) further has a constituent unit (B) derived from at least one monomer (b) selected from the group consisting of terpene monomers and vinyl monomers. By having the above constituent unit (B) in the tackifying resin (T2-1), the adhesive strength of the adhesive layer (Y2) can be further improved. Furthermore, from the viewpoint of improving compatibility with the base polymer (P2), the tackifying resin (T2-1) is preferably composed of structural units derived from terpene monomers. Since the structural units derived from terpene monomers have an aliphatic hydrocarbon group having an unsaturated double bond, the compatibility between the tackifying resin (T2-1) and the base polymer (P2) is improved when the tackifying resin (T2-1) has structural units derived from terpene monomers, and a decrease in the adhesive strength of the adhesive layer (Y2) due to deterioration of compatibility can be suppressed.

[0107] Examples of the above-mentioned terpene monomers include α-pinene, β-pinene, limonene, dipentene, δ-3-carene, dimethyloctatriene, allocimene, myrcene, ocimene, linalool, and cosmene. Among these, α-pinene, β-pinene, or limonene are preferred because they can further improve the adhesive strength of the adhesive layer (Y2). As the vinyl monomers mentioned above, vinyl monomers that do not have a structure containing two or more aromatic rings in one molecule (for example, naphthalene structure, anthracene structure, biphenyl structure, anthraquinone structure, benzophenone structure, etc.) are preferred from the viewpoint of improving the compatibility between the tackifying resin (T2-1) and the base polymer (P2). Examples of vinyl monomers that do not have a structure containing two or more aromatic rings in a single 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 improve the adhesive strength of the adhesive layer (Y2). The above monomer (b) may be used alone or in combination of two or more types.

[0108] The above-mentioned component unit (B) may consist solely of petroleum-derived materials, but it is preferable that it includes bio-derived materials. The depletion of petroleum resources and the emission of carbon dioxide from the combustion of petroleum-derived products are serious concerns. Therefore, attempts are being made to conserve petroleum resources by using bio-derived materials instead of petroleum-derived materials. It is preferable from the standpoint of conserving petroleum resources if the above-mentioned component unit (B) includes bio-derived materials. Furthermore, if the above-mentioned component unit (B) includes bio-derived materials, since bio-derived materials are originally produced by absorbing carbon dioxide from the atmosphere, it is thought that burning them will not increase the total amount of carbon dioxide in the atmosphere, which is also preferable from the standpoint of reducing carbon dioxide emissions. Examples of monomers (b) that constitute the above-mentioned constituent unit (B) containing bio-derived materials include terpene monomers, ethylene, propylene, hexene, and the like.

[0109] The preferred lower limit for the content of the constituent unit (B) in the tackifying resin (T2-1) is 40 mol%, and the preferred upper limit is 99 mol%. By having a content of 40 mol% or more of the constituent unit (B), the tackifying resin (T2-1) can have the desirable physical properties required for a tackifying resin. By having a content of 99 mol% or less of the constituent unit (B), the content of the constituent unit (A) can be sufficiently secured, thereby further improving the adhesive strength of the adhesive layer (Y2), and in particular, further improving the adhesive strength even to adherends with low polarity. The more preferred lower limit for the content of the constituent unit (B) is 50 mol%, and the more preferred upper limit is 90 mol%.

[0110] The tackifying resin (T2-1) is preferably a copolymer having a structure represented by the following formula. In particular, when the above constituent unit (A) is present in or at the end of the main chain skeleton, it is preferable that the copolymer has a structure represented by the following formula. Copolymers having such a structure are obtained by a cationic polymerization method as described later, and can further improve the adhesive strength of the adhesive layer (Y2), and in particular can further improve the adhesive strength even to low-polarity adherends.

[0111] [ka]

[0112] In the formula, A represents a constituent unit (A), B represents a constituent unit (B), and s and t each represent an integer greater than or equal to 1. * represents a connection.

[0113] The tackifying resin (T2-1) is preferably a copolymer having the above-mentioned structural unit (A) and the above-mentioned structural unit (B), and may further have other structural units. When the tackifying resin (T2-1) is a copolymer having the above-mentioned structural unit (A) and the above-mentioned structural unit (B), the above-mentioned structural unit (A) and the above-mentioned structural unit (B) may be copolymerized randomly, or they may be copolymerized in a regular or periodic manner, for example, when each forms a block segment and the block segments are bonded to each other.

[0114] The tackifying resin (T2-1) preferably has an aliphatic hydrocarbon group having an unsaturated double bond. The tackifying resin (T2-1) may have the aliphatic hydrocarbon group having an unsaturated double bond in the constituent unit (A) or the constituent unit (B), or in other constituent units. In particular, from the viewpoint of ease of synthesis and improving the compatibility between the tackifying resin (T2-1) and the base polymer (P2), and especially between the tackifying resin (T2-1) and the styrene elastomer, it is preferable that the aliphatic hydrocarbon group having an unsaturated double bond is present in the constituent unit (B) or other constituent units. The constituent unit (B) or other constituent units having such aliphatic hydrocarbon group having an unsaturated double bond are not particularly limited, but it is preferable that the constituent unit (B) is derived from at least one monomer (b) selected from the group consisting of terpene monomers and vinyl monomers. In other words, it is preferable that the tackifying resin (T2-1) has the aliphatic hydrocarbon group having an unsaturated double bond in a constituent unit (B) derived from at least one monomer (b) selected from the group consisting of terpene monomers and vinyl monomers. In particular, it is preferable that the aliphatic hydrocarbon group having an unsaturated double bond is contained in a constituent unit derived from a terpene monomer, as this can further improve the adhesive strength of the adhesive layer (Y2).

[0115] Other constituent units mentioned above include, for example, constituent units derived from other phenolic monomers not included in constituent unit (A), and constituent units derived from maleic anhydride. Other phenolic monomers mentioned above include, for example, phenol, cresol, xylenol, propylphenol, norylphenol, methoxyphenol, bromophenol, bisphenol A, bisphenol F, bisphenol S, and dihydroxynaphthalene. The other phenolic monomers mentioned above may be used individually or in combination of two or more.

[0116] The preferred lower limit of the weight-average molecular weight (Mw) of the above tackifying resin (T2-1) is 400, and the preferred upper limit is 10,000. When the weight-average molecular weight (Mw) of the above tackifying resin (T2-1) is within this range, the above tackifying resin (T2-1) possesses the desirable physical properties required for a tackifying resin. A more preferred lower limit of the weight-average molecular weight (Mw) of the above tackifying resin (T2-1) is 500, a more preferred upper limit is 5000, an even more preferred lower limit is 700, and an even more preferred upper limit is 3000. Methods for adjusting the weight-average molecular weight (Mw) of the tackifying resin (T2-1) to the above range include, for example, adjusting the composition, polymerization method, polymerization conditions, etc. of the tackifying resin (T2-1).

[0117] The preferred lower limit of the Young's modulus of the tackifying resin (T2-1) at 25°C is 10 MPa. A Young's modulus of 10 MPa or higher at 25°C for the tackifying resin (T2-1) provides appropriate hardness and desirable physical properties required for a tackifying resin. A more preferred lower limit for the Young's modulus of the tackifying resin (T2-1) at 25°C is 50 MPa, and an even more preferred lower limit is 70 MPa. Furthermore, from the viewpoint of preventing the adhesive layer (Y2) from becoming too hard and reducing the adhesive strength, the preferred upper limit for the Young's modulus of the tackifying resin (T2-1) at 25°C is 10,000 MPa, and the more preferred upper limit is 5,000 MPa. The Young's modulus of the tackifying resin (T2-1) at 25°C can be measured by performing a tensile test using a tensile testing machine (such as the "Autograph" manufactured by Shimadzu Corporation) under the conditions of a tensile speed of 200 mm / min, a grip distance of 15 mm, and a temperature of 25°C. A sample for this measurement can be obtained, for example, by filling a mold measuring 10 × 50 mm with the tackifying resin (T2-1) and melting it at a temperature 100°C higher than the glass transition temperature to produce a test piece with a thickness of 1 mm.

[0118] Methods for adjusting the Young's modulus of the tackifying resin (T2-1) at 25°C to within the above range include, for example, adjusting the molecular weight or weight-average molecular weight of the tackifying resin (T2-1), the composition and content ratio of the constituent units (A) and (B) in the tackifying resin (T2-1), etc.

[0119] The preferred lower limit for the glass transition temperature of the tackifying resin (T2-1) is 0°C, and the preferred upper limit is 200°C. Because the glass transition temperature of the tackifying resin (T2-1) is within this range, the Young's modulus of the tackifying resin (T2-1) at 25°C is easily adjusted to within this range, thus the tackifying resin (T2-1) possesses the desirable physical properties required for a tackifying resin. A more preferred lower limit for the glass transition temperature of the tackifying resin (T2-1) is 10°C, and a more preferred upper limit is 150°C.

[0120] The preferred lower limit of the iodine value of the tackifying resin (T2-1) is 2.0 g / 100 g, and the preferred upper limit is 180 g / 100 g. Having an iodine value of 2.0 g / 100 g or higher makes it easier to suppress the decrease in adhesive strength of the adhesive layer (Y2) caused by poor compatibility between the tackifying resin (T2-1) and the base polymer (P2). Having an iodine value of 180 g / 100 g or lower further improves the adhesive strength of the adhesive layer (Y2), and in particular, it can further improve adhesive strength even to low-polarity substrates. A more preferred lower limit of the iodine value of the tackifying resin (T2-1) is 70 g / 100 g, and a more preferred upper limit is 170 g / 100 g. The iodine value is an indicator of the amount of unsaturated double bonds (C=C bond amount), and refers to the value measured in accordance with the method described in "JIS K 0070:1992".

[0121] The preferred lower limit for the content of bio-derived carbon (carbon atoms) in the carbon (carbon atoms) of the above-mentioned tackifying resin (T2-1) is 10%. A bio-derived carbon content of 10% or more is an indicator that a product is "bio-based". The above tackifying resin (T2-1) is preferable if it contains 10% or more bio-derived carbon, from the viewpoint of conserving petroleum resources and reducing carbon dioxide emissions. A more preferable lower limit for the bio-derived carbon content of the above tackifying resin (T2-1) is 30%, an even more preferable lower limit is 60%, an even more preferable lower limit is 70%, and a particularly preferable lower limit is 90%. There is no particular preferred upper limit for the bio-derived carbon content of the above tackifying resin (T2-1), and it may be 100%. Furthermore, while bio-derived carbon contains a certain percentage of the radioactive isotope (C-14), petroleum-derived carbon contains almost no C-14. Therefore, the percentage of bio-derived carbon in the above-mentioned tackifying resin (T2-1) 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 widely used in the bioplastics industry.

[0122] The tackifying resin (T2-1) described above also includes hydrogenated compounds of the compounds mentioned above. A hydrogenated compound is a compound in which at least partially the carbon-carbon double bonds present in the tackifying resin (T2-1) described above have been saturated by hydrogenation. That is, the adhesive composition (X2) may contain a hydrogenated compound in which some of the carbon-carbon double bonds in the tackifying resin (T2-1) have been hydrogenated, or it may contain a hydrogenated compound in which all of the carbon-carbon double bonds in the tackifying resin (T2-1) have been hydrogenated. Even such a hydrogenated compound can be suitably used as a tackifying resin to be blended into the adhesive composition (X2), and can improve the adhesive strength of the adhesive layer (Y2), and in particular can improve the adhesive strength even to adherends with low polarity.

[0123] The method for producing the above-mentioned tackifying resin (T2-1) is not particularly limited, but when the above-mentioned constituent unit (A) is present in or at the end of the main chain skeleton, the following method is preferred, for example. In other words, a method of copolymerizing monomer (a) constituting the above-mentioned structural unit (A) with at least one monomer (b) selected from the group consisting of terpene monomers and vinyl monomers constituting the above-mentioned structural unit (B) (hereinafter also referred to as "production method [I]") is preferred.

[0124] 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), which are represented by the following formula.

[0125] [ka]

[0126] [ka]

[0127] [ka]

[0128] [ka]

[0129] In formulas (a-1) to (a-4), R 1 ~R 7 Each of the following 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'' represents an integer between 2 and 5, preferably 2 or 3, and more preferably 3. m'' represents an integer between 1 and 5. l'' represents an integer between 2 and 5. k'' represents an integer between 1 and 5.

[0130] In the method for producing the tackifying resin (T2-1) described above [I], it is preferable to copolymerize monomer (a) and monomer (b) by cationic polymerization. By using the cationic polymerization described above, monomer (a) and monomer (b) can be copolymerized without prior chemical modification to protect the functional groups of monomer (a), such as phenolic hydroxyl groups, carboxyl groups, alkoxy groups, and amino groups, and subsequent deprotection is also unnecessary. Therefore, monomer (a) and monomer (b) can be copolymerized in a simpler one-step reaction process, leading to a reduction in impurities and an improvement in yield.

[0131] A preferred method for copolymerizing monomer (a) and monomer (b) by cationic polymerization is to react monomer (a) and monomer (b) in the presence of a Lewis acid. This method is thought to generate cations of monomer (b), leading to cationic polymerization between monomers (b) and a Fridel-Crafts alkylation reaction between monomer (a) and monomer (b). Repeated reactions of this nature allow for the production of a copolymer having constituent units (A) derived from monomer (a) and constituent units (B) derived from monomer (b). The Lewis acid mentioned above is not particularly limited, and conventionally known Lewis acids can be used, such as aluminum chloride (AlCl3), diethylaluminum chloride (Et2AlCl2), tin(IV) chloride (SnCl4), titanium(IV) chloride (TiCl4), boron trichloride (BCl3), and boron trifluoride ether complex (BF3·EtO). Among these, aluminum chloride (AlCl3) is preferred because it yields a higher yield of copolymer.

[0132] More specifically, for example, if pyrogallol is used as monomer (a) and α-pinene is used as monomer (b), and these are reacted in the presence of aluminum chloride (AlCl3), which is a Lewis acid, the reaction shown in the following scheme is expected to proceed. Specifically, a cation of monomer (b), α-pinene, is generated, and cationic polymerization of α-pinenes proceeds (upper part of the scheme below), while a Fridel-Crafts alkylation reaction proceeds between monomer (a), pyrogallol, and monomer (b), α-pinene (middle part of the scheme below). By repeatedly performing such 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 will have structural units derived from pyrogallol in the main chain skeleton or at the ends of the main chain skeleton.

[0133] [ka]

[0134] In the expression, s and t each represent an integer greater than or equal to 1. * represents a concatenation.

[0135] As for the method of producing the above-mentioned tackifying resin (T2-1), if the above-mentioned structural unit (A) is present in the side chain, for example, the following method is preferred. In other words, a method of copolymerizing a monomer (a') obtained by introducing an unsaturated double bond to monomer (a) constituting the above-mentioned structural unit (A), with at least one monomer (b) selected from the group consisting of terpene monomers and vinyl monomers constituting the above-mentioned structural unit (B) (hereinafter also referred to as "production method [II]") is preferred.

[0136] Examples of the above monomer (a') include 2-vinylbenzoic acid, 3-vinylbenzoic acid, 4-vinylbenzoic acid, and 4,4'-stilbendicarboxylic acid. Among these, 4-vinylbenzoic acid is preferred because it has less steric hindrance and readily interacts with the adherend. The above monomer (a') may be used alone or in combination of two or more types.

[0137] In the above method for producing the tackifying resin (T2-1) [II], it is preferable to copolymerize the monomer (a') and the monomer (b) by cationic polymerization, similar to the method for producing the tackifying resin (T2-1) [I]. A preferred method for copolymerizing monomer (a') and monomer (b) by cationic polymerization is to react monomer (a') and monomer (b) in the presence of a Lewis acid as described above. By such a method, cationic polymerization proceeds between the unsaturated double bond in monomer (a') and the unsaturated double bond in monomer (b), and a copolymer having constituent units (A) derived from monomer (a') and constituent units (B) derived from monomer (b) can be obtained.

[0138] The above-mentioned tackifying resin (T2-1) can improve the adhesive strength of the adhesive layer (Y2) even in a small amount compared to conventional tackifying resins. The preferred lower limit of the content of the above-mentioned tackifying resin (T2-1) per 100 parts by mass of the above-mentioned base polymer (P2) is 5 parts by mass, and the preferred upper limit is 30 parts by mass. By having a content of 5 parts by mass or more of the above-mentioned tackifying resin (T2-1), the adhesive strength of the adhesive layer (Y2) can be further improved, and in particular, the adhesive strength to low-polarity adherends (e.g., fluororesins, etc.) can be further improved. By having a content of 30 parts by mass or less of the above-mentioned tackifying resin (T2-1), a decrease in adhesive strength caused by the adhesive layer (Y2) becoming too hard can be suppressed. The more preferred lower limit of the content of the above-mentioned tackifying resin (T2-1) is 10 parts by mass, and the more preferred upper limit is 20 parts by mass.

[0139] The tackifying resin preferably includes at least one tackifying resin (T2-2) selected from the group consisting of rosin ester resins, terpene resins, terpene phenol resins, and petroleum resins. By including the tackifying resin (T2-2), the adhesive strength of the adhesive layer (Y2) can be further improved. In particular, the tackifying resin (T2-2) is more preferably made up of at least one tackifying resin selected from the group consisting of rosin ester resins and terpene resins because it can further improve the adhesive strength to low-polarity adherends (e.g., fluororesins, etc.), and the tackifying resin (T2-2) is even more preferably made up of a rosin ester resin because it can further improve the adhesive strength to low-polarity adherends (e.g., fluororesins, etc.). Examples of the above-mentioned rosin ester resin, terpene resin, terpene phenol resin, and petroleum resin include those similar to those used in the tackifying resin (T1) described above.

[0140] The preferred lower limit for the content of the tackifying resin (T2-2) per 100 parts by mass of the base polymer (P2) is 10 parts by mass, and the preferred upper limit is 100 parts by mass. A content of 10 parts by mass or more of the tackifying resin (T2-2) can further improve the adhesive strength of the adhesive layer (Y2). A content of 100 parts by mass or less of the tackifying resin (T2-2) can prevent the adhesive layer (Y2) from becoming too hard and reducing its adhesive strength. A more preferred lower limit for the content of the tackifying resin (T2-2) is 15 parts by mass, a more preferred upper limit is 60 parts by mass, an even more preferred upper limit is 50 parts by mass, and an even more preferred upper limit is 40 parts by mass.

[0141] The adhesive composition (X2) preferably contains a crosslinking agent. In particular, if the base polymer (P2) contains the (meth)acrylic copolymer, the adhesive composition (X2) preferably contains a crosslinking agent. By containing the crosslinking agent in the adhesive composition (X2), the (meth)acrylic copolymer can form a crosslinked structure by chemical crosslinking, thereby improving the bulk cohesive force of the adhesive layer (Y2) and increasing the gel fraction of the adhesive layer (Y2), as described later, thus improving the adhesive strength of the resulting adhesive sheet. Furthermore, from the viewpoint of storage stability and other factors, the crosslinking agent may be added to the adhesive composition (X2) immediately before forming the adhesive layer (Y2).

[0142] Examples of the crosslinking agents include isocyanate-based crosslinking agents, aziridine-based crosslinking agents, epoxy-based crosslinking agents, and metal chelate-type crosslinking agents. In particular, it is preferable that the crosslinking agent includes at least one selected from the group consisting of isocyanate-based crosslinking agents and epoxy-based crosslinking agents, as this enables appropriate chemical crosslinking of the (meth)acrylic copolymer and further improves the adhesive strength of the adhesive layer (Y2). Examples of the above-mentioned isocyanate-based crosslinking agent and epoxy-based crosslinking agent include those the same as those used in the above-mentioned adhesive composition (X1).

[0143] The preferred lower limit for the content of the crosslinking agent in the above adhesive composition (X2) per 100 parts by mass of the (meth)acrylic copolymer is 0.01 parts by mass, and the preferred upper limit is 20 parts by mass. Having the crosslinking agent content within this range allows for appropriate chemical crosslinking of the (meth)acrylic copolymer, further improving the adhesive strength of the adhesive layer (Y2). A more preferred lower limit for the crosslinking agent content is 0.1 parts by mass, a more preferred upper limit is 10 parts by mass, an even more preferred lower limit is 0.5 parts by mass, and an even more preferred upper limit is 8.0 parts by mass.

[0144] The above adhesive composition (X2) may further contain a coloring agent for the purpose of providing light-shielding properties. Examples of the coloring agent include carbon black, aniline black, and titanium dioxide. Among these, carbon black is preferred because it is relatively inexpensive and chemically stable.

[0145] The above adhesive composition (X2) may optionally contain conventionally known fine particles and additives such as inorganic fine particles, conductive fine particles, antioxidants, foaming agents, organic fillers, and inorganic fillers.

[0146] The preferred lower limit for the gel fraction of the adhesive layer (Y2) is 15% by mass, and the preferred upper limit is 60% by mass. When the gel fraction of the adhesive layer (Y2) is 15% by mass or more, the bulk strength of the adhesive layer (Y2) is increased, and the resulting adhesive sheet has superior adhesion. When the gel fraction of the adhesive layer (Y2) is 60% by mass or less, the flexibility of the adhesive layer (Y2) is further improved, and the adhesion strength of the adhesive layer (Y2) to the fluororesin is further improved. The more preferred lower limit for the gel fraction of the adhesive layer (Y2) is 25% by mass, and the more preferred upper limit is 50% by mass. The gel fraction of the adhesive layer (Y2) can be measured using the same method as described above for the gel fraction of the adhesive layer (Y1).

[0147] The gel fraction of the adhesive layer (Y2) can be adjusted to within the above range by, for example, changing the type or constituent units of the base polymer (P2) (for example, changing the type of monomer constituting the (meth)acrylic copolymer), adjusting the content ratio of the base polymer (P1), adjusting the weight-average molecular weight of the (meth)acrylic copolymer, or adjusting the type and content of the crosslinking agent.

[0148] The adhesive layer (Y2) has a preferred lower limit of anchor strength of 5.0 N / 25 mm for the sheet containing the fluororesin at 23°C. A higher anchor strength of 5.0 N / 25 mm or more for the adhesive layer (Y2) for the sheet containing the fluororesin at 23°C improves adhesion between the adhesive layer (Y2) and the sheet containing the fluororesin in the laminated sheet, allowing the laminated sheet to firmly bond the fluororesin to a can or the like. A more preferred lower limit for the anchor strength of the adhesive layer (Y2) for the sheet containing the fluororesin at 23°C is 7.0 N / 25 mm, and an even more preferred lower limit is 10 N / 25 mm. Furthermore, there is no specific upper limit to the anchoring strength of the adhesive layer (Y2) against the sheet containing the fluororesin at 23°C, but the practical upper limit is 100 N / 25 mm.

[0149] The anchoring strength of the adhesive layer (Y2) with respect to the sheet containing the fluororesin at 23°C can be measured by the following method. Specifically, an adhesive sheet backed with the adhesive layer (Y1) using a 50 μm thick PET film is cut to a size of 25 mm wide x 100 mm long. Then, the adhesive layer (Y2) side is placed on a 2 mm thick sheet containing fluororesin (for example, "Yodoflon" manufactured by Yodogawa Hutech Co., Ltd.), and pressed together by one back-and-forth motion using a 2 kg rubber roller at a speed of 300 mm / min. After that, the laminate A is produced by curing it for 24 hours in an environment of 23°C and 50% RH. For the obtained laminate A, a 180° peel test is performed using a tensile testing machine (such as "Autograph" manufactured by Shimadzu Corporation) in accordance with JIS Z 0237, under conditions of 23°C, 50% RH, and a peeling speed of 300 mm / min. By peeling the double-sided adhesive sheet from the sheet containing fluororesin, the 180° peel force of the adhesive layer (Y2) against the fluororesin-containing sheet at 23°C is measured, and the obtained 180° peel force can be obtained as the anchor strength of the adhesive layer (Y2) against the fluororesin-containing sheet at 23°C.

[0150] Methods for adjusting the anchor strength of the adhesive layer (Y2) to the sheet containing the fluororesin at 23°C to the above range include, for example, changing the type or constituent units of the base polymer (P2) (for example, changing the copolymerization ratio or monomer composition of the base polymer (P2)), adjusting the type or content of the tackifying resin (T2), changing the thickness of the adhesive layer (Y2), or changing the substrate.

[0151] The preferred lower limit for the thickness of the adhesive layer (Y2) is 50 μm, and the preferred upper limit is 1000 μm. The adhesive layer (Y2) having a thickness within this range ensures sufficient adhesive strength. A more preferred lower limit for the thickness of the adhesive layer (Y2) is 100 μm, a more preferred upper limit is 500 μm, and an even more preferred upper limit is 300 μm.

[0152] The above-mentioned double-sided adhesive sheet preferably has a base material. Having a base material results in a double-sided adhesive sheet with superior bonding workability.

[0153] From the viewpoint of heat resistance and chemical resistance, the above-mentioned substrate 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.

[0154] Furthermore, the adhesive layer may peel off easily due to the generation of air at the adhesive surface when the substrate is pressed against the adhesive layer. Therefore, it is preferable that the substrate includes at least one shape selected from the group consisting of nonwoven fabrics and woven fabrics, as this improves the anchoring strength of the substrate and improves air release properties by providing air passages to suppress air generation, thereby suppressing the peeling of the adhesive layer.

[0155] Examples of commercially available nonwoven fabric substrates include G2260-1S (manufactured by Toray International). Examples of the woven base material mentioned above include glass cloth and carbon cloth. Examples of commercially available glass cloths among those mentioned above include KS2770 (manufactured by Nitto Boseki Co., Ltd.) and L73A×1045 (manufactured by Arisawa Seisakusho Co., Ltd.). Among the carbon cloths mentioned above, commercially available examples include C-540 (manufactured by Hagiwara Industries Co., Ltd.).

[0156] The preferred lower limit for the thickness of the above substrate is 50 μm, and the preferred upper limit is 1000 μm. Having the substrate thickness within this range further improves the interlayer strength of the double-sided adhesive sheet. A more preferred lower limit for the thickness of the above substrate is 100 μm, and a more preferred upper limit is 500 μm.

[0157] The above double-sided adhesive sheet has a minimum thickness of 250 μm. A thickness of 250 μm or more allows the double-sided adhesive sheet to achieve a high level of both adhesive strength and ease of application. A preferred minimum thickness for the above double-sided adhesive sheet is 300 μm, and a more preferred minimum thickness is 400 μm. Furthermore, from the viewpoint of preventing the load on the double-sided adhesive sheet due to its own weight from becoming too large, the preferred upper limit for the thickness of the double-sided adhesive sheet is 1200 μm, and the more preferred upper limit is 1000 μm.

[0158] When the above double-sided adhesive sheet includes a base material, the preferred upper limit of the ratio of the thickness of the base material to the thickness of the double-sided adhesive sheet is 35%. A ratio of 35% or less for the base material results in superior adhesive reliability for the double-sided adhesive sheet. A more preferred upper limit for the ratio of the base material thickness is 30%, and an even more preferred upper limit is 25%. Furthermore, from the viewpoint of increasing the overall strength of the tape by the base material, the preferred lower limit for the ratio of the base material thickness is 1%, and the more preferred lower limit is 3%.

[0159] The above-mentioned double-sided adhesive sheet may have layers other than the adhesive layer and the substrate, as long as they do not impair the effects of the present invention.

[0160] Preferably, the laminated sheet further includes a separator. The presence of a separator in the laminated sheet protects the adhesive layer on the outermost surface of the double-sided adhesive sheet and suppresses a decrease in the adhesive strength of the outermost adhesive layer, thereby improving the adhesive reliability when the double-sided adhesive sheet in the laminated sheet is bonded to a can or the like.

[0161] The separator is preferably composed of at least one material selected from the group consisting of polyester resin, polyolefin resin, and paper. By being composed of at least one material selected from the group consisting of polyester resin, polyolefin resin, and paper, the separator has excellent resistance to the heat and tension applied during tape manufacturing, and thermal shrinkage and damage to the separator can be prevented.

[0162] Examples of separators made from the above-mentioned polyester resin include polyethylene terephthalate (PET) film, polyethylene-2,6-naphthalate (PEN) film, polybutylene terephthalate (PBT) film, polypropylene terephthalate (PPT) film, or films made from copolymers mainly composed of the constituent components of these resins. Examples of separators made from the above-mentioned polyolefin resin include polypropylene film, polyethylene film, polyethylene-vinyl acetate copolymer (EVA) film, and the like. Examples of separators made from the above-mentioned paper include kraft paper, fine paper, and glassine paper.

[0163] The separator preferably has a release layer. Having a release layer makes it easier to reduce the 180° peel force at 23°C when the separator is peeled from the double-sided adhesive sheet, as described later, making the separator easier to peel off. Therefore, when peeling the separator, it becomes possible to further suppress the peeling of the adhesive layer in contact with the fluororesin-containing sheet from the fluororesin-containing sheet.

[0164] In this specification, the term "release layer" includes not only a layer on the surface of the separator substrate that has been treated with a release agent, but also a layer that has release properties even if it has not been treated with a release agent on its surface. Examples of the above-mentioned mold release treatments include corona treatment, plasma treatment, sandblasting, chemical etching, and application of mold release agents such as silicone-based release agents. Examples of layers that have release properties even without the above-mentioned release treatment include polyolefin resin-based release layers and fluororesin-based release layers.

[0165] The separator preferably has a release layer containing at least one release agent selected from the group consisting of polyolefin resin-based release agents, silicone-based release agents, and fluororesin-based release agents. In the laminated sheet of the wound body of the present invention 1, the separator has a release layer containing at least one release agent selected from the group consisting of polyolefin-based release agents, silicone-based release agents, and fluororesin-based release agents, thereby providing appropriate release properties to the adhesive layer.

[0166] Examples of the polyolefin resin-based release agents mentioned above include polyethylene and polypropylene. Examples of the above-mentioned silicone-based release agents include polyorganosiloxanes. Examples of the above-mentioned fluororesin-based release agents include polyorganosiloxanes having fluorine-containing functional groups in their side chains.

[0167] The preferred lower limit for the thickness of the release layer is 0.02 μm, and the preferred upper limit is 1.0 μm. A thickness of 0.02 μm or more in the release layer makes it easier to reduce the 180° peel force between the separator and the double-sided adhesive sheet, thereby further suppressing the peeling of the adhesive layer in contact with the fluororesin-containing sheet during separator removal. A thickness of 1 μm or less in the release layer provides the necessary adhesion between the separator and the adhesive layer of the double-sided adhesive sheet to protect the adhesive layer. A more preferred lower limit for the thickness of the release layer is 0.05 μm, and a more preferred upper limit is 0.5 μm.

[0168] The thickness of the separator described above has a preferred lower limit of 15 μm and a preferred upper limit of 100 μm. A separator thickness of 15 μm or more ensures that the separator and the adhesive layer of the double-sided adhesive sheet have the necessary adhesion to protect the adhesive layer. A release layer thickness of 100 μm or less makes it easier to reduce the 180° peel force between the separator and the double-sided adhesive sheet, thereby further suppressing the peeling of the adhesive layer in contact with the fluororesin-containing sheet when the separator is removed. A more preferred lower limit of 23 μm and a more preferred upper limit of 75 μm is used for the release layer thickness.

[0169] When the separator is peeled from the double-sided adhesive sheet, the preferred lower limit of the 180° peel force at 23°C is 150 mN / 50 mm, and the preferred upper limit is 2000 mN / 50 mm. A 180° peel force of 150 mN / 50 mm or more at 23°C ensures that the separator has the necessary adhesion to protect the adhesive layer. A 180° peel force of 2000 mN / 50 mm or less at 23°C ensures that the separator is not too hard, preventing it from becoming stuck to the adhesive layer during use. Furthermore, it becomes possible to further suppress the peeling of the adhesive layer in contact with the fluororesin-containing sheet during separator removal. When the separator is peeled from the double-sided adhesive sheet, the more preferable lower limit of the 180° peel force at 23°C is 250 mN / 50 mm, and the more preferable upper limit is 1600 mN / 50 mm. The following are examples of methods for measuring the 180° peel force at 23°C when the separator is peeled from the double-sided adhesive sheet. Specifically, first, the laminated sheet is cut to a size of 50 mm in width and 100 mm in length to prepare a test specimen. Then, the prepared test specimen can be measured by peeling the separator from the double-sided adhesive sheet at a 180° angle using a tensile testing machine (such as Shimadzu Corporation's "Autograph") in accordance with JIS Z0237, under conditions of 23°C and a peeling speed of 300 mm / min.

[0170] Methods for adjusting the 180° peel force when the separator is peeled from the double-sided adhesive sheet include introducing a release layer to the separator, adjusting the thickness of the release layer, changing the composition of the adhesive layer adjacent to the separator (for example, the adhesive layer (Y1)), adding a tackifying resin, and adjusting the thickness of the adhesive layer adjacent to the separator (for example, increasing the thickness of the adhesive layer to increase the 180° peel force).

[0171] The method for manufacturing the above-mentioned laminated sheet is not particularly limited, and examples include the following methods. First, an adhesive solution (a) containing an adhesive composition (X1) is prepared by adding a base polymer (P1), a tackifying resin (T1), and, if necessary, a crosslinking agent or solvent. The obtained adhesive solution (a) is applied to the surface of the release layer of a separator such as a release PET film, and the solvent in the solution is dried and removed to create a laminated film (a) in which an adhesive layer (Y1) is formed on the surface of the separator. The prepared laminated film is placed on a substrate so that the adhesive layer (Y1) and the substrate face each other, and cured for 48 hours in an environment of 40°C and 50%RH to obtain a laminate of the substrate and a laminate having the adhesive layer (Y1) on one side of the substrate. Note that the step of applying the adhesive solution (a) to the separator may be completed in one step, or it may be performed multiple times by applying it on top of the applied adhesive solution. By adjusting the number of application steps, the thickness of the adhesive layer (Y1) can be easily adjusted. Next, an adhesive solution (b) containing an adhesive composition (X2) is prepared by adding a base polymer (P2), a tackifying resin (T2), and, if necessary, a crosslinking agent or solvent. The obtained adhesive solution (b) is applied to the surface of the release layer of the separator, and the solvent in the solution is dried and removed to create a laminated film (b) in which an adhesive layer (Y2) is formed on the surface of the separator. Note that the step of applying the adhesive solution (b) to the separator may be performed once, or it may be performed multiple times by applying it on top of the applied adhesive solution. By adjusting the number of application steps, the thickness of the adhesive layer (Y2) can be easily adjusted. Furthermore, the substrate and the side of the substrate without the adhesive layer (Y1) in a laminate having an adhesive layer (Y1) on one side of the substrate are superimposed so that the adhesive layer (Y2) in the laminated film (b) faces each other. Then, the adhesive layer (Y2) and the protective separator are peeled off, and the adhesive layer (Y2) and the sheet containing fluororesin are superimposed to form a laminated unit. By curing for 48 hours in an environment of 40°C and 50%RH, a laminated sheet having the separator, adhesive layer (Y1), substrate, adhesive layer (Y2), and sheet containing fluororesin in this order can be manufactured.

[0172] The laminated sheet described above has a minimum thickness of 350 μm. A thickness of 350 μm or more improves the peelability of the separator, making it easier to peel from the double-sided adhesive sheet. A preferred minimum thickness for the laminated sheet of the present invention is 375 μm, and a more preferred minimum thickness is 400 μm. Furthermore, from the viewpoint of preventing the load due to the self-weight of the laminated sheet from becoming too large, the preferred upper limit for the thickness of the laminated sheet of the present invention is 1400 μm, and the more preferred upper limit is 1300 μm.

[0173] From the viewpoint of being able to be manufactured using a roll-to-roll method, the laminated sheet is preferably in a long shape. The length of the laminated sheet is not particularly limited, but a preferred lower limit for the length of the laminated sheet is 10m, and a more preferred lower limit is 20m. Furthermore, from the viewpoint of preventing the weight from becoming too large when the material is wound, the preferred upper limit for the length of the laminated sheet is 100m, and the more preferred upper limit is 50m.

[0174] The width of the laminated sheet is not particularly limited, but from the viewpoint of manufacturing efficiency, a preferred lower limit for the width of the laminated sheet is 300 mm, a preferred lower limit is 2100 mm, a more preferred lower limit is 500 mm, and a more preferred upper limit is 1500 mm.

[0175] The method for manufacturing the winding body of the present invention is not particularly limited, and it can be manufactured by winding a laminated sheet onto a winding core using a conventionally known method.

[0176] In the present invention, it is preferable that the winding body is wound such that the sheet containing fluororesin is on the outside. By winding the winding body of the present invention such that the sheet containing fluororesin is on the outside, the bending stress on the adhesive sheet is reduced, and the occurrence of tunneling can be suppressed.

[0177] The applications of the winding body of the present invention are not particularly limited, but it is suitably used for joining fluororesin to dissimilar members for various purposes. More specifically, these purposes include, for example, promoting sliding of friction surfaces, preventing friction of sliding parts, insulating coating, and protecting adherends from high temperatures or chemical solutions. In particular, it is suitably used for protecting adherends, and especially suitably for protecting adherends from chemical solutions. Furthermore, since the laminated sheet in the winding body of the present invention has excellent adhesive reliability, it can achieve high-strength bonding, making it suitably used for easily joining fluororesin to cans and the like. Specifically, it is more suitably used for lining (surface treatment covering the inner surface of a can) of a chemical tank, and even more suitably used for lining a chemical tank for semiconductors or for the chemical industry. In addition, the winding body of the present invention exhibits minimal tunneling and excellent handling when removing the laminated sheet. Furthermore, in the winding body of the present invention, the laminated sheet makes it easier to suppress the peeling of the adhesive layer in contact with the sheet containing fluororesin from the sheet containing fluororesin when the separator is peeled off, and makes it easier to bond the fluororesin to the can body or the like.

[0178] A method for manufacturing a chemical tank, which includes a step of laminating a lining sheet to the inside of the tank body of the chemical tank, is also one of the present inventions. The present invention provides a method for manufacturing a chemical tank that suppresses the peeling of the separator of the laminated sheet when pressing a sheet containing fluororesin, and allows for easy bonding of the fluororesin to the tank body, resulting in superior work efficiency.

[0179] A chemical tank in which a double-sided adhesive sheet from the laminated sheet of the present invention is attached to the inner surface of a can is also one of the present inventions. The chemical tank of the present invention allows for a strong bond of fluororesin to the inner surface of the tank body via the attached double-sided adhesive sheet, thereby further suppressing peeling and lifting of the fluororesin caused by the chemical solution stored in the chemical tank to which the fluororesin is bonded. [Effects of the Invention]

[0180] According to the present invention, it is possible to provide a wound body that exhibits less floating (tunneling), is easy to handle, and allows for easy bonding of fluororesin to a can or the like. Furthermore, according to the present invention, it is possible to provide a method for manufacturing a chemical tank using the wound body. Moreover, according to the present invention, it is possible to provide a chemical tank in which a laminated sheet is attached to the wound body. [Modes for carrying out the invention]

[0181] The embodiments of the present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0182] (Preparation of release agent solution) (Release agent solution 1) To 100 parts by mass of silicone composition (Toray Dow Corning, "LTC759"), 1 part by mass of curing catalyst (Toray Dow Corning, "SRX212") and 900 parts by mass of toluene as a solvent were added and thoroughly stirred to prepare mold release agent solution 1.

[0183] (Release agent solution 2-4) Release agent solutions 2 to 4 were prepared in the same manner as release agent solution 1, except that their compositions were as shown in Table 1.

[0184] [Table 1]

[0185] (Separator fabrication) (Separator G) A 75 μm thick PET film (Toyobo Co., Ltd., "S10") prepared as a separator substrate was coated with release agent solution 3 to a dry thickness of 0.5 μm, and then dried at 130°C for 1 minute to form a release layer, thereby producing a separator G having a 0.5 μm thick release layer on one side of the PET film.

[0186] (Separators H, J) Separators H and J, each having a release layer on one side, were prepared in the same manner as separator G, except that the type of separator substrate and the type of release agent solution were as shown in Table 2.

[0187] (Separator I) A coating solution for forming a sealing layer was prepared by adding 900 parts by mass of methanol to 100 parts by mass of polyvinyl alcohol (Sekisui Chemical Co., Ltd., "BL-1") and stirring thoroughly. A separator substrate with a thickness of 85 μm and a basis weight of 64 g / m² was prepared. 2A sealing layer was formed on the surface of high-quality paper (manufactured by Nippon Paper Industries, "P-1") by applying the above sealing layer forming solution to a dry thickness of 2 μm, and then drying it at 130°C for 1 minute. On the sealing layer surface of the high-quality paper with the sealing layer formed on it, a release agent solution 2 was applied to a dry thickness of 0.5 μm, and then drying it at 130°C for 1 minute to form a release layer, thereby creating a separator I with a release layer of 0.5 μm thickness on one side of the high-quality paper.

[0188] [Table 2]

[0189] (Preparation of tackifying resin (T2-1)) (Synthesis Example 1) Fifty parts by mass of toluene were added to a reactor equipped with a thermometer, stirrer, and condenser, and after purging with nitrogen, the reactor was heated and reflux was started. After 30 minutes, while maintaining the toluene at 75°C, two parts by mass of aluminum chloride (AlCl3) were added. A solution of 50 parts by mass of catechol (pyrocatechol) (n=2) and α-pinene (molar ratio: α-pinene / catechol = 80 / 20) dissolved in 50 parts by mass of toluene was gradually added dropwise over 1 hour and 30 minutes to allow the reaction to proceed. After polymerization for 4 hours, the hydrochloric acid generated from aluminum chloride (AlCl3) was neutralized by cooling while adding 0.1 parts by mass of pyridine to the reactor. The precipitate formed by neutralization was filtered, and after liquid-liquid extraction of the obtained filtrate, the toluene was evaporated to obtain a solid tackifying resin (T2-1). Regarding the obtained tackifying resin (T2-1) 1 ¹H-NMR measurements were performed to confirm that the tackifying resin (T2-1) is a copolymer having constituent units (A) derived from catechol (pyrocatechol) and constituent units (B) derived from α-pinene (a copolymer having constituent unit (A) in or at the ends of the main chain skeleton). The obtained tackifying resin (T2-1) was dissolved in tetrahydrofuran, and the resulting solution was filtered through a filter (material: polytetrafluoroethylene, pore diameter: 0.2 μm). The obtained filtrate was supplied to a gel permeation chromatograph (Waters, 2690 Separations Module), and GPC measurements were performed under conditions of sample flow rate of 1 mL / min and column temperature of 40°C. The polystyrene-equivalent molecular weight of the tackifying resin (T2-1) was measured, and the weight-average molecular weight (Mw) was determined to be 950. A GPC KF-802.5L column (Showa Denko) was used, and a differential refractometer was used as the detector.

[0190] (Synthesis Example 2) Except for changing the constituent monomer units to a total of 50 parts by mass of pyrogallol (n=3) and α-pinene (molar ratio: α-pinene / pyrogallol = 80 / 20), the tackifying resin (T2-1) was synthesized in the same manner as in "(Synthesis Example 1)" above, and measurements were performed. The weight-average molecular weight was 1100.

[0191] (Preparation of adhesive) (Adhesive A) To 100 parts by mass of solids of an acrylic adhesive containing a (meth)acrylic copolymer as a base polymer (manufactured by Soken Chemical Co., Ltd., "SK Dyne 1604N"), 20 parts by mass of a rosin ester resin (manufactured by Arakawa Chemical Industries, Ltd., "Pine Crystal KE-359") was added as a tackifying resin. Furthermore, 30 parts by mass of ethyl acetate (manufactured by Fuji Chemical Co., Ltd.) and 2.5 parts by mass of an isocyanate crosslinking agent (manufactured by Covestro, Inc., "Desmodule L-75") were added to prepare the adhesive composition, and by thoroughly stirring, adhesive A was obtained.

[0192] (Gel fraction of the adhesive layer) First, the obtained adhesive A was applied to the release treatment surface of a 75 μm thick release PET film, and then dried at 100°C for 5 minutes to produce an adhesive sheet for gel fraction measurement with a 50 μm thick adhesive layer. Next, the obtained adhesive sheet for measuring the gel fraction was cut into a size of 20 mm in width and 40 mm in length. After the cut test piece was immersed in ethyl acetate at 23°C for 24 hours, it was taken out from the organic solvent and dried at 110°C for 1 hour. Then, the mass of the dried test piece was measured, and the gel fraction was calculated using the following formula (2). Note that the test piece is not laminated with a release PET film for protecting the adhesive layer. Also, W0 in formula (2) was calculated as 0. The results are shown in Table 3. Gel fraction (mass %) = 100×(W2 - W0) / (W1 - W0) (2) (W0: mass of the base material, W1: mass of the test piece before immersion, W2: mass of the test piece after immersion and drying)

[0193] (Preparation of the adhesive) (Adhesives B to E) Adhesives B to E were prepared in the same manner as adhesive A, except that the composition was made as shown in Table 3, and the gel fraction of the adhesive layer was measured. The results are shown in Table 3.

[0194] (Adhesive F) Adhesive F was prepared in the same manner as adhesive A, except that the composition was made as shown in Table 3 and 30 parts by mass of toluene was used instead of 30 parts by mass of ethyl acetate. Also, the gel fraction of the adhesive layer was measured in the same manner as adhesive A, except that the organic solvent for immersion was changed from ethyl acetate to toluene. The results are shown in Table 3.

[0195]

Table 3

[0196] (Example 1) (1) Manufacture of the wound body After applying the obtained adhesive A onto the surface of the release layer of separator G using a comma coater, drying it at 100 °C for 5 minutes, and then drying it at 130 °C for 10 minutes, an adhesive layer (Y1) with a thickness of 200 μm was formed on the surface of the release layer of separator G, and a laminated film was produced. A PET film with a thickness of 50 μm (manufactured by Toyobo Co., Ltd., "E5200") was prepared as a base material, and the produced laminated film was overlaid on the base material such that the adhesive layer (Y1) faced the base material, obtaining a laminate having the base material and an adhesive layer (Y1) on one surface of the base material. Also, after applying the obtained adhesive A onto the surface of the release layer of separator I using a comma coater, drying it at 100 °C for 5 minutes, and then drying it at 130 °C for 10 minutes, an adhesive layer (Y2) with a thickness of 200 μm was formed on the surface of the release layer of separator I. Next, it was overlaid so as to face the surface having the base material of the laminate having the adhesive layer (Y2), obtaining a laminate having a separator, an adhesive layer (Y1), a base material, an adhesive layer (Y2), and a separator in this order. Furthermore, after laminating and producing a laminated sheet (width: 900 mm, length: 30 m) by overlaying the exposed adhesive layer (Y2) after peeling off the separator I adjacent to the adhesive layer (Y2) and a sheet containing 2.0 mm thick PTFE (manufactured by Yodogawa Huetec Co., Ltd., "Yodoflon", PTFE sheet) prepared as a sheet containing a fluororesin so that they faced each other, winding it around a core (material: ABS resin, outer diameter: 172 mm), and aging it for 48 hours in an environment of 40 °C and 50% RH, a wound body was obtained. Note that the winding direction was set such that the sheet containing the fluororesin of the laminated sheet was on the outer side of the winding.

[0197] [[ID=IO]](2) Measurement of the 180° peel strength at 23 °C when the separator was peeled off from the double-sided adhesive sheet Laminated sheets were removed from the obtained windings and cut into pieces measuring 50 mm in width and 100 mm in length to prepare test specimens. Next, the prepared test specimens were tested using a tensile testing machine (Shimadzu Corporation, "Autograph") in accordance with JIS Z 0237. The separator was peeled 180° from the double-sided adhesive sheet at 23°C and a peeling speed of 300 mm / min to measure the 180° peel force between the separator and the double-sided adhesive sheet at 23°C. The results are shown in Table 4.

[0198] (3) Measurement of the 180° peel force of the adhesive layer (Y1) against SUS at 23°C A laminated sheet was removed from the obtained winding and cut into pieces measuring 25 mm in width and 100 mm in length to prepare test specimens. Next, after peeling off the separator from the test specimens, the adhesive layer (Y1) side was washed with ethanol and then wiped dry. The specimens were then placed on a 2 mm thick SUS304 plate, and a laminate was fabricated by pressurizing them at 0.1 MPa for 1 hour in an environment of 120°C. The obtained laminates were subjected to a 180° peel test in accordance with JIS Z 0237, using a Shimadzu Corporation "Autograph" instrument, under conditions of 23°C, 50% RH, and a peeling speed of 300 mm / min. The 180° peel force of the adhesive layer (Y1) relative to the SUS plate at 23°C was measured by peeling the adhesive sheet from the SUS plate. The results are shown in Table 4.

[0199] (4) Measurement of the anchor strength of the adhesive layer (Y2) against a fluorine-containing resin sheet at 23°C Laminated sheets were removed from the obtained windings, the separator of the removed laminated sheets was peeled off, and the adhesive layer (Y1) side was backed with a 23 μm thick PET film (Futamura Chemical Co., Ltd., "FE2002"), and then cut to a size of 25 mm wide x 100 mm long to prepare test specimens. Next, a 180° peel test was performed on the prepared test specimens using a Shimadzu Corporation "Autograph" in accordance with JIS Z 0237, at 23°C and a peeling speed of 300 mm / min. The adhesive layer (Y2) was peeled from the fluorine-containing resin sheet, and the 180° peel force of the adhesive layer (Y2) against PTFE at 23°C was measured. This 180° peel force was defined as the anchor strength of the adhesive layer (Y2) against the fluorine-containing resin sheet at 23°C. The results are shown in Table 4.

[0200] (Examples 2-10, 15-16, 19-28, 30, Comparative Example 1) In the above-described "(1) Manufacturing of the wound body," a laminated sheet (width 800 mm, length 20 m) and a wound body were manufactured in the same manner as in Example 1, except that the type of separator, the composition of the adhesive composition (X1), the thickness of the adhesive layer (Y1), the type and thickness of the substrate, the composition of the adhesive composition (X2), and the thickness of the adhesive layer (Y2) were as shown in Tables 4 to 7, and measurements were taken. The results are shown in Tables 4 to 7.

[0201] (Examples 11, 18) One surface of a 2.0 mm thick PTFE-containing sheet (Yodogawa Hutech Co., Ltd., "Yodoflon", PTFE sheet), used as a fluororesin-containing sheet, was subjected to atmospheric pressure plasma treatment at 60V using an atmospheric pressure plasma device (Sakigake Semiconductor Co., Ltd., "TK-50"). Laminated sheets (800 mm wide, 20 m long) and wound bodies were prepared and measured in the same manner as in Examples 2-10, 15-16, 19-28, 30, and Comparative Example 1, except that the adhesive layer (Y2) formed using a sheet containing fluororesin that had undergone atmospheric pressure plasma treatment was superimposed on the atmospheric pressure plasma-treated surface of the fluororesin-containing sheet. The results are shown in Table 5.

[0202] (Example 12) One surface of a 2.0 mm thick PTFE-containing sheet (Yodogawa Hutech Co., Ltd., "Yodoflon", PTFE sheet), used as a fluororesin-containing sheet, was subjected to electron beam irradiation treatment using an electron beam irradiation device (NHV Corporation, "EBC-200") under the conditions of an acceleration voltage of 150 kV and an irradiation intensity of 400 kGy. Laminated sheets (800 mm wide, 20 m long) and wound bodies were prepared and measured in the same manner as in Examples 2-10, 15-16, 19-28, 30, and Comparative Example 1, except that the adhesive layer (Y2) formed using a sheet containing electron beam irradiation treated fluororesin was superimposed on the electron beam irradiation treated surface of the fluororesin-containing sheet. The results are shown in Table 5.

[0203] (Example 13) A 2.0 mm thick PTFE-containing sheet (Yodogawa Hutech Co., Ltd., "Yodoflon", PTFE sheet), used as a fluororesin-containing sheet, was uniformly coated with a naphthalene solution of metallic sodium and then washed off with a large amount of toluene after 1 minute, thereby performing sodium etching. Laminated sheets (800 mm wide, 20 m long) and wound bodies were prepared and measured in the same manner as in Examples 2-10, 15-16, 19-28, 30, and Comparative Example 1, except that the adhesive layer (Y2) formed using a fluororesin sheet that had undergone sodium etching treatment was superimposed on the sodium-etched surface of the fluororesin-containing sheet. The results are shown in Table 5.

[0204] (Example 14) A 2.0 mm thick PTFE-containing sheet (Yodogawa Hutech Co., Ltd., "Yodoflon", PTFE sheet), used as a sheet containing fluororesin, was subjected to a glass cloth backing treatment by layering a 100 μm thick PFA film (Yodogawa Hutech Co., Ltd., "Yodoflon", PFA sheet) and a 300 μm thick glass cloth (Nitto Boseki Co., Ltd., "KS2770") in that order onto one surface and pressing it at 360°C and 0.5 MPa. Laminated sheets (800 mm wide, 20 m long) and wound bodies were prepared and measured in the same manner as in Examples 2-10, 15-16, 19-28, 30, and Comparative Example 1, except that the adhesive layer (Y2) formed using a fluororesin-containing sheet that had undergone the glass cloth backing treatment was superimposed on the glass cloth backing treatment surface of the fluororesin-containing sheet. The results are shown in Table 5. Note that the surface density of the fluororesin-containing sheet in Example 14, as shown in Table 5, is the surface density of the fluororesin-containing sheet after glass cloth backing treatment.

[0205] (Example 17) The obtained adhesive A was applied to the surface of the release layer of the prepared separator G using a comma coater, dried at 100°C for 5 minutes, and then dried at 130°C for 10 minutes to form an adhesive layer (Y1) with a thickness of 200 μm on the surface of the release layer of the separator G, thereby producing a laminated film. A laminated sheet (900 mm wide, 30 m long) was prepared by layering a 2.0 mm thick PTFE-containing sheet (manufactured by Yodogawa Hutech Co., Ltd., "Yodoflon") onto the adhesive layer (Y1) of the obtained laminated film. This sheet was then wound onto a core (material: ABS resin, outer diameter: 172 mm) and cured for 48 hours in an environment of 40°C and 50% RH to obtain a wound body. The winding direction was set so that the fluororesin-containing sheet of the laminated sheet was on the outside of the winding. Furthermore, various measurements were performed in the same manner as in Example 1. The results are shown in Table 5.

[0206] (Example 29) One surface of a 2.0 mm thick PTFE-containing sheet (Yodogawa Hutech Co., Ltd., "Yodoflon") used as a fluororesin-containing sheet was subjected to atmospheric pressure plasma treatment at 60V using an atmospheric pressure plasma device (Sakigake Semiconductor Co., Ltd., "TK-50"). The obtained adhesive A was applied to the surface of the release layer of the prepared separator I using a comma coater, dried at 100°C for 5 minutes, and then dried at 130°C for 10 minutes to form an adhesive layer (Y1) with a thickness of 200 μm on the surface of the release layer of separator I, thereby preparing a laminated film. A PET film with a thickness of 50 μm (Toyobo Co., Ltd., "E5200") was prepared as the substrate, and the prepared laminated film was superimposed on the substrate so that the adhesive layer (Y1) faced the substrate, thereby obtaining a laminate having the substrate and the adhesive layer (Y1) on one side of the substrate. The obtained adhesive A was applied to the surface of the release layer of the prepared separator I using a comma coater, dried at 100°C for 5 minutes, and then dried at 130°C for 10 minutes to form an adhesive layer (Y2) with a thickness of 200 μm on the surface of the release layer of separator I. Next, the adhesive layer (Y2) was superimposed on the surface of the prepared laminate having the substrate, thereby obtaining a laminate having the separator, adhesive layer (Y1), substrate, adhesive layer (Y2), and separator in this order. After peeling off the adhesive layer (Y2) and the adjacent separator in the obtained laminate, the atmospheric pressure plasma-treated side of a 2.0 mm thick PTFE-containing sheet (manufactured by Yodogawa Hutech Co., Ltd., "Yodoflon") that had been subjected to atmospheric pressure plasma treatment by the above method was superimposed on the adhesive layer (Y2). Then, the separator adjacent to the adhesive layer (Y1) was peeled off to produce a laminated sheet (800 mm wide, 20 m long) having the adhesive layer (Y1), substrate, adhesive layer (Y2), and fluororesin-containing sheet in this order. A winding was then prepared in the same manner as in Example 1, and cured for 48 hours in an environment of 40°C and 50% RH to obtain a winding of a laminated sheet having a double-sided adhesive sheet and a fluororesin-containing sheet. The various measurements were performed in the same manner as in Example 1. The results are shown in Table 6.

[0207] <Evaluation> The obtained wound body was evaluated by the following method. The results are shown in Tables 4 to 7.

[0208] (Adhesion reliability) A laminated sheet was taken out from the obtained wound body, cut into a size of 210 mm in width and 297 mm in length, and after peeling off the separator for protecting the adhesive layer (Y1) of the laminated sheet as necessary, it was heated at 100 °C for 3 minutes and immediately the adhesive layer (Y1) was bonded along the circumferential direction on the inner side surface of a mirror plate (manufactured by Ohamahira Press Co., Ltd., "10% additional type mirror plate"). After bonding, the adhesiveness between the double-sided adhesive sheet, the sheet containing fluororesin, and the mirror plate, and the lifting of the above laminate from the mirror plate were visually observed. Evaluation was carried out according to the following criteria. ○: No lifting occurred from any layer. △: Partial lifting occurred between the adhesive layer (Y2) and the sheet containing fluororesin, or between the adhesive layer (Y1) and the mirror plate. ×: Peeling occurred between the adhesive layer (Y2) and the sheet containing fluororesin, or between the adhesive layer (Y1) and the mirror plate.

[0209] (Tunneling of the wound body) In the above-mentioned "(2) Manufacture of the wound body", the manufactured wound body was visually observed, and the tunneling of the wound body was evaluated according to the following criteria. ○: There was no tunneling. △: Tunneling occurred at one or more places and five or fewer places. ×: Tunneling occurred at six or more places.

[0210] (Peeling of the adhesive layer (Y2) from the sheet containing fluororesin due to peeling of the separator) For Examples 1-28, 30, and Comparative Example 1, which are windings of laminated sheets with separators, the laminated sheets were removed from the obtained windings, cut to a size of 50 mm wide x 100 mm long, and then the separator protecting the adhesive layer (Y2) was peeled off using tweezers. At that time, the presence or absence of peeling from the fluororesin-containing sheet in the adhesive layer (Y2) was observed. Evaluation was performed according to the following criteria. ○: No peeling occurred from the fluororesin-containing sheet in the adhesive layer (Y2). △: In the adhesive layer (Y2), peeling from the sheet containing fluororesin occurred only at the edges. ×: In the adhesive layer (Y2), peeling occurred beyond the edges of the sheet containing fluororesin.

[0211] [Table 4]

[0212] [Table 5]

[0213] [Table 6]

[0214] [Table 7] [Industrial applicability]

[0215] According to the present invention, it is possible to provide a wound body that exhibits less floating (tunneling), is easy to handle, and allows for easy bonding of fluororesin to a can or the like. Furthermore, according to the present invention, it is possible to provide a method for manufacturing a chemical tank using the wound body. Moreover, according to the present invention, it is possible to provide a chemical tank in which a laminated sheet is attached to the wound body.

Claims

1. A winding body having a structure in which laminated sheets are wound around a core, The outer diameter of the aforementioned core is 160 mm or more and 550 mm or less. The laminated sheet comprises a resin sheet containing fluororesin and a double-sided adhesive sheet having an adhesive layer. A coiled body characterized by the following features.

2. The adhesive layer in the double-sided adhesive sheet includes an adhesive layer (Y1) formed using an adhesive composition (X1) and an adhesive layer (Y2) formed using an adhesive composition (X2). The laminated sheet has a structure in which the sheet containing the fluororesin and the adhesive layer (Y2) are adjacent to each other. The winding body according to claim 1.

3. The winding body according to claim 1 or 2, wherein the sheet containing the fluororesin includes a sheet containing polytetrafluoroethylene (PTFE).

4. The winding body according to claim 1 or 2, wherein the sheet containing the fluororesin has an easy-adhesion treatment layer on its surface.

5. The winding body according to claim 4, wherein the easy-adhesion treatment in the easy-adhesion treatment layer is at least one selected from the group consisting of plasma irradiation, electron beam irradiation, chemical etching, and easy-adhesion layer bonding.

6. The winding body according to claim 1 or 2, wherein the sheet containing the fluororesin has a thickness of 1.0 mm or more and 4.0 mm or less.

7. The sheet containing the aforementioned fluororesin has a surface density of 1 kg / m². ２ More than 10kg / m ２ The following is the winding body according to claim 1 or 2.

8. The wound body according to claim 1 or 2, wherein the total thickness of the adhesive layer in the double-sided adhesive sheet is 300 μm or more and 1500 μm or less.

9. The adhesive composition (X1) contains a base polymer (P1), The base polymer (P1) comprises at least one selected from the group consisting of (meth)acrylic copolymers and styrene-based elastomers. The winding body according to claim 2.

10. The winding body according to claim 2 or 9, wherein the adhesive composition (X1) further contains a tackifying resin (T1).

11. The winding body according to claim 2 or 9, wherein the adhesive layer (Y1) has a 180° peel force of 50 N / 25 mm or more against SUS at 23°C. The described coiled body.

12. The winding body according to claim 2 or 9, wherein the adhesive composition (X2) further contains a tackifying resin (T2).

13. The winding body according to claim 12, wherein the tackifying resin (T2) comprises a tackifying resin (T2-1) having at least one constituent unit (A) selected from the group consisting of constituent units (A-1), (A-1'), (A-2), (A-2'), (A-3), (A-3'), (A-4), and (A-4') represented by the following formula. 【Chemistry 1】 【Chemistry 2】 【Transformation 3】 【Chemistry 4】 In the formula, R １ ~R ７ * 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, respectively. n and l each represent an integer between 2 and 4, and n' and l' each represent an integer between 2 and 5. m and k each represent an integer between 1 and 4, and m' and k' each represent an integer between 1 and 5. * represents a linking part.

14. The winding body according to claim 2, 9, 12, or 13, wherein the adhesive layer (Y2) has an anchor strength of 5.0 N / 25 mm or more against the sheet containing the fluororesin at 23°C.

15. The double-sided adhesive sheet has a base material, The substrate 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. The winding body according to claim 1 or 2.

16. The winding body according to claim 1 or 2, wherein the laminated sheet further comprises a separator.

17. The winding body according to claim 16, wherein the separator is composed of at least one selected from the group consisting of polyester resin, polyolefin resin, and paper.

18. The wound body according to claim 16, wherein the separator has a release layer containing at least one release agent selected from the group consisting of polyolefin-based release agents, silicone-based release agents, and fluororesin-based release agents.

19. The wound body according to claim 16, wherein the 180° peel force at 23°C when the separator is peeled from the double-sided adhesive sheet is 150 mN / 50 mm or more and 2000 mN / 50 mm or less.

20. A wound body according to claim 1 or 2, used for lining a tank body in a chemical tank.

21. A method for manufacturing a chemical tank, comprising the step of bonding the laminated sheet in the wound body according to claim 1 or 2 to the inside of the can body of the chemical tank.

22. A chemical tank in which the laminated sheet of the wound body according to claim 1 or 2 is attached to the inside of the can body of the chemical tank.

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