Adhesive tape, chemical tank, and method for manufacturing chemical tank

Abstract

The present invention provides an adhesive tape which has excellent holding performance, is low in pollution to an adherend, and can be easily bonded with a fluororesin. Another purpose of the present invention is to provide a liquid medicine tank to which the adhesive tape is attached. The purpose of the present invention is also to provide a method for manufacturing a chemical tank using the adhesive tape. The present invention relates to an adhesive tape having a base material and a first adhesive layer adjacent to one surface of the base material, the base material comprising a resin film containing a fluororesin, the first adhesive layer comprising a base polymer (P1) and a tackifying resin, the base polymer (P1) contains at least one type selected from the group consisting of a (meth) acrylic copolymer and a styrene elastomer.

Description

Technical Field

[0001] The present invention relates to an adhesive tape, a liquid medicine tank to which the adhesive tape is affixed, and a method for manufacturing a liquid medicine tank using the adhesive tape. Background Art

[0002] Adhesive tapes have long been widely used to secure components in electronic devices. Specifically, for example, adhesive tapes are used to bond a cover plate, used to protect the surface of a portable electronic device, to a touch panel module or display panel module, or vice versa. Adhesive tapes used to secure components in these electronic devices require not only high adhesion but also, depending on the environment in which they are used, properties such as heat resistance, thermal conductivity, and impact resistance (e.g., Patent Documents 1-3).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2015-052050

[0006] Patent Document 2: Japanese Patent Application Laid-Open No. 2015-021067

[0007] Patent Document 3: Japanese Patent Application Laid-Open No. 2015-120876 Summary of the Invention

[0008] Problems to be solved by the invention

[0009] In recent years, demand for fluororesins has increased across a variety of fields due to their excellent heat resistance, chemical resistance, low dielectric properties, and water resistance. For example, tetrafluoroethylene copolymer (PTFE) is used in a wide range of fields, including wire coatings and building materials, due to its high mechanical strength and excellent processability.

[0010] Fluororesins are typically used to bond dissimilar materials together, but fluororesins have difficulty exhibiting the adhesive properties of adhesive tape, making bonding difficult using conventional adhesive tape. Therefore, methods commonly used to bond fluororesins to dissimilar materials include: applying a liquid adhesive to a fluororesin surface treated to facilitate adhesion; attaching the fluororesin using adhesive tape using a silicone adhesive; and applying an alkaline hydrophilic treatment to the fluororesin surface to enhance the adhesive's adhesion. However, the use of liquid adhesives presents challenges in terms of complex processes, contamination of bonded components due to volatilization and penetration of low-molecular-weight components when using silicone adhesives, and environmental pollution caused by the wastewater generated during the alkaline hydrophilic treatment.

[0011] The present invention provides an adhesive tape that exhibits excellent holding performance, minimizes adherend contamination, and facilitates fluororesin bonding. Another object of the present invention is to provide a chemical tank to which the adhesive tape is affixed. Furthermore, the present invention provides a method for manufacturing a chemical tank using the adhesive tape.

[0012] Means for solving problems

[0013] Disclosure 1 relates to a pressure-sensitive adhesive tape comprising a substrate and a first pressure-sensitive adhesive layer adjacent to one surface of the substrate, wherein the substrate comprises a resin film containing a fluororesin, and the first pressure-sensitive adhesive layer comprises a base polymer (P1) and a tackifier resin, wherein the base polymer (P1) comprises at least one selected from a (meth)acrylic copolymer and a styrene elastomer.

[0014] Disclosure 2 relates to the adhesive tape of Disclosure 1, which comprises the substrate, the first adhesive layer, an intermediate layer, and a second adhesive layer in this order, wherein the second adhesive layer contains a base polymer (P2), and the base polymer (P2) contains at least one selected from a (meth)acrylic copolymer and a styrene elastomer.

[0015] Disclosure 3 relates to the adhesive tape of Disclosure 2, wherein the probe tack of the second adhesive layer measured under the conditions of 23°C, 98 gf pressure, 100 mm / sec pressure speed, 10 seconds pressure time, and 5 mm / sec separation speed is 20 N / 5 mmφ or less.

[0016] Present Disclosure 4 relates to the pressure-sensitive adhesive tape of Present Disclosure 1, which includes the substrate, the first pressure-sensitive adhesive layer, and a hot-melt pressure-sensitive adhesive layer in this order.

[0017] Disclosure 5 relates to the pressure-sensitive adhesive tape of Disclosure 1, 2, 3, or 4, wherein, in the base polymer (P1), the (meth)acrylic copolymer comprises a structural unit derived from an alkyl (meth)acrylate having an alkyl group having 4 to 12 carbon atoms at the ester terminal, and at least one structural unit selected from a structural unit derived from a carboxyl group-containing (meth)acrylate and a structural unit derived from a hydroxyl group-containing (meth)acrylate.

[0018] Disclosure 6 relates to the adhesive tape of Disclosure 5, wherein the alkyl (meth)acrylate having an alkyl group of 4 to 12 carbon atoms at the ester terminal includes an alkyl (meth)acrylate having an alkyl group of 6 to 8 carbon atoms at the ester terminal.

[0019] Disclosure 7 relates to the adhesive tape of Disclosure 5 or 6, wherein the alkyl (meth)acrylate having an alkyl group having 4 to 12 carbon atoms at the ester terminal includes n-heptyl (meth)acrylate.

[0020] Disclosure 8 relates to the pressure-sensitive adhesive tape of Disclosure 6 or 7, wherein the content ratio of the structural unit derived from the alkyl (meth)acrylate having an alkyl group having 6 to 8 carbon atoms at the ester terminal in the (meth)acrylic copolymer is 50% by mass or more and 99.5% by mass or less.

[0021] Disclosure 9 relates to the pressure-sensitive adhesive tape of Disclosure 1, 2, 3, 4, 5, 6, 7 or 8, wherein the tackifying resin comprises: a tackifying resin (T1) having at least one structural unit (A) 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), structural unit (A-3'), structural unit (A-4) and structural unit (A-4') represented by the following formula.

[0022] Present Disclosure 10 relates to the pressure-sensitive adhesive tape of Present Disclosure 9, wherein the tackifier resin (T1) further includes a structural unit (B) derived from at least one monomer (b) selected from terpene-based monomers and vinyl-based monomers.

[0023] Present disclosure 11 relates to the pressure-sensitive adhesive tape of present disclosure 9 or 10, wherein the content of the tackifier resin (T1) is 5 parts by mass or more and 50 parts by mass or less relative to 100 parts by mass of the base polymer (P1).

[0024] Disclosure 12 relates to the adhesive tape of Disclosure 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or 11, wherein the tackifier resin comprises at least one tackifier resin (T2) selected from rosin ester resins, terpene resins, terpene phenol resins, and petroleum resins.

[0025] Present Disclosure 13 relates to the pressure-sensitive adhesive tape of Present Disclosure 12, wherein the tackifier resin (T2) contains a rosin ester resin.

[0026] Present Disclosure 14 relates to the pressure-sensitive adhesive tape of Present Disclosure 12 or 13, wherein the tackifier resin (T2) has a softening temperature of 50° C. or higher and 200° C. or lower.

[0027] Disclosure 15 relates to the adhesive tape of Disclosure 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13 or 14, wherein the first adhesive layer does not contain an organosilicon compound, or the content of the organosilicon compound in the first adhesive layer is 3.0% by mass or less.

[0028] Disclosure 16 relates to the adhesive tape of Disclosure 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 or 15, wherein the first adhesive layer has a 180° peel strength to the substrate at 23°C of 2.5 N / 25 mm or more.

[0029] Disclosure 17 relates to the pressure-sensitive adhesive tape of Disclosure 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or 16, wherein the first pressure-sensitive adhesive layer has a peak in a temperature range of -30°C to 15°C, as measured at a frequency of 10 Hz in a dynamic viscoelasticity measurement.

[0030] Disclosure 18 relates to the adhesive tape of Disclosure 17, wherein the shear storage modulus of the first adhesive layer at 25° C. measured at a frequency of 10 Hz in a dynamic viscoelasticity measurement is 1.0×10 4 Pa or more and 5.0×10 5 Pa or less, the loss tangent (tan δ) of the first pressure-sensitive adhesive layer measured at a frequency of 10 Hz in a dynamic viscoelasticity measurement has a peak in a temperature range of -30°C to 15°C.

[0031] Disclosure 19 relates to the pressure-sensitive adhesive tape of Disclosure 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, or 18, wherein the gel fraction of the first pressure-sensitive adhesive layer is 15% by mass or more and 70% by mass or less.

[0032] Disclosure 20 relates to the pressure-sensitive adhesive tape of Disclosure 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, or 19, wherein the thickness of the first pressure-sensitive adhesive layer is 20 μm or more and 500 μm or less.

[0033] Disclosure 21 relates to the adhesive tape of Disclosure 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20, wherein the resin film containing a fluororesin comprises at least one selected from glass cloth impregnated with a fluororesin and a laminated film in which a fluororesin layer and a glass cloth layer are laminated.

[0034] Disclosure 22 relates to the adhesive tape of Disclosure 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 or 21, wherein the thickness of the substrate is 50 μm or more and 5000 μm or less.

[0035] Disclosure 23 relates to the adhesive tape of Disclosure 2 or 3, wherein the second adhesive layer of the adhesive tape has a 180° peel strength with respect to SUS at 23° C. of 8.0 N / 25 mm or less.

[0036] Disclosure 24 relates to the pressure-sensitive adhesive tape according to Disclosure 2, 3, or 23, wherein the second pressure-sensitive adhesive layer has a thickness of 20 μm to 500 μm.

[0037] Disclosure 25 relates to the adhesive tape of Disclosure 2, 3, 23 or 24, wherein the intermediate layer comprises at least one selected from polyester resin, polyimide resin, polyolefin resin, polyurethane resin, glass fiber, carbon fiber and metal.

[0038] Disclosure 26 relates to the adhesive tape of Disclosure 2, 3, 23, 24 or 25, wherein the intermediate layer has a foamed structure.

[0039] Disclosure 27 relates to the adhesive tape of Disclosure 4, wherein when the hot melt adhesive layer is pressurized to SUS at 0.1 MPa for 10 minutes at 150°C, the adhesive tape has a 180° peel strength to SUS of 5.0 N / 25 mm or more at 23°C.

[0040] Disclosure 28 relates to the adhesive tape of Disclosure 4 or 27, wherein the hot-melt adhesive layer contains a base polymer (P3), and the base polymer (P3) includes at least one selected from the group consisting of (meth)acrylic copolymers, styrene elastomers, ethylene-vinyl acetate copolymers, chloroprene rubber, nitrile rubber, polyurethane resins, polyamide resins, polyolefin resins, polyester resins, and epoxy resins.

[0041] Disclosure 29 relates to the adhesive tape of Disclosure 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27 or 28, which is used for protecting an adherend.

[0042] Disclosure 30 relates to the adhesive tape of Disclosure 29, wherein the adhesive tape is used to protect an adherend from chemical liquids.

[0043] Disclosure 31 relates to the adhesive tape of Disclosure 30, which is used for lining a tank body in a chemical liquid tank for semiconductors or a chemical liquid tank for the chemical industry.

[0044] The present disclosure 32 relates to a liquid medicine tank, wherein the adhesive tape of the present disclosure 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30 or 31 is adhered to the inner surface of the tank body.

[0045] The present disclosure 33 relates to a method for manufacturing a chemical liquid tank for semiconductors or a chemical liquid tank for the chemical industry, which includes a process of sticking the adhesive tape of the present disclosure 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30 or 31 to the inner surface of the tank body in the chemical liquid tank.

[0046] [Chemical Formula 1]

[0047]

[0048] [Chemical Formula 2]

[0049]

[0050] [Chemical Formula 3]

[0051]

[0052] [Chemical Formula 4]

[0053]

[0054] Where R 1 ~R 7 Respectively represent a hydrogen atom, an aliphatic hydrocarbon group, an aromatic hydrocarbon group, a polar functional group, an aliphatic hydrocarbon group having a polar functional group, or an aromatic hydrocarbon group having a polar functional group. n and l represent an integer of 2 or more and 4 or less, n' and l' represent an integer of 2 or more and 5 or less, m and k represent an integer of 1 or more and 4 or less, m' and k' represent an integer of 1 or more and 5 or less, respectively. Indicates a connection part.

[0055] Hereinafter, the present invention will be described in detail.

[0056] The present inventors have studied adhesive tapes comprising a substrate and an adhesive layer adjacent to the substrate. The inventors have investigated methods such as forming the substrate with a resin film containing a fluororesin, using a (meth)acrylic copolymer and a styrene elastomer as the base polymer of the adhesive layer, and including a tackifier resin in the adhesive layer. They have discovered that an adhesive tape can be obtained that exhibits excellent holding performance, exhibits low adherend contamination, and facilitates fluororesin bonding, leading to the completion of the present invention.

[0057] In this specification, "(meth)acrylic acid" refers to acrylic acid or methacrylic acid. In this specification, "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 layer.

[0058] The pressure-sensitive adhesive tape of the present invention has a substrate.

[0059] The substrate includes a resin film containing a fluororesin. By including a resin film containing a fluororesin in the substrate, the adhesive tape of the present invention can easily bond the fluororesin to a different material.

[0060] Examples of the fluororesin contained in the fluororesin-containing resin film include polytetrafluoroethylene (PTFE), perfluoroalkoxyalkane (PFA), perfluoroethylene-propylene copolymer (FEP), ethylene-tetrafluoroethylene copolymer (ETFE), polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), polychlorotrifluoroethylene (PCTFE), and ethylene-chlorotrifluoroethylene copolymer (ECTFE). Among these, PTFE is preferred due to its excellent heat resistance and chemical resistance.

[0061] The fluororesin-containing resin film is not particularly limited as long as it is a film, and may comprise at least one selected from a fluororesin-impregnated glass cloth film and a laminated film comprising a fluororesin layer and a glass cloth layer. By including at least one selected from a fluororesin-impregnated glass cloth film and a laminated film comprising a fluororesin layer and a glass cloth layer, the number of interfaces between the substrate and the first adhesive layer increases, thereby further enhancing the reliability of the bond between the substrate and the first adhesive layer.

[0062] Examples of the fluororesin-impregnated glass cloth film include a PTFE-impregnated glass cloth sheet (manufactured by Chuko Chemical Industries, Ltd.).

[0063] Examples of the laminated film in which a fluororesin layer and a glass cloth layer are laminated include a glass back sheet (manufactured by Yodogawa Hu-Tech Co., Ltd.).

[0064] The preferred lower limit of the thickness of the substrate is 20 μm, and the preferred upper limit is 5000 μm. By setting the thickness of the substrate to 20 μm or greater, a sufficient thickness of fluororesin can be bonded to the adherend, making the resulting adhesive tape more suitable for use, for example, in protecting the adherend. Setting the thickness of the substrate to 5000 μm or less allows for easy roll-up of the adhesive tape, further improving its manufacturing efficiency. A more preferred lower limit of the thickness of the substrate is 40 μm, and a more preferred upper limit is 3000 μm.

[0065] In this specification, the thickness can be measured using a dial thickness gauge (such as “ABS DIGIMATIC INDICATOR” manufactured by Mitutoyo Co., Ltd.) or the like.

[0066] The pressure-sensitive adhesive tape of the present invention includes a first pressure-sensitive adhesive layer adjacent to one surface of the substrate.

[0067] The first pressure-sensitive adhesive layer contains a base polymer (P1).

[0068] The base polymer (P1) contains one selected from a (meth)acrylic acid copolymer and a styrene-based elastomer. By including one selected from a (meth)acrylic acid copolymer and a styrene-based elastomer in the first adhesive layer, the resulting adhesive tape can be less likely to contaminate adherends. In particular, the base polymer (P1) preferably contains a (meth)acrylic acid copolymer, as forming a crosslinked structure further improves the adhesive tape's holding power.

[0069] The (meth)acrylic acid-based copolymer preferably has a structural unit derived from an alkyl (meth)acrylate.

[0070] The alkyl (meth)acrylate preferably comprises an alkyl (meth)acrylate having an alkyl group with 4 to 12 carbon atoms at the ester terminus. That is, the (meth)acrylic copolymer preferably comprises a structural unit derived from an alkyl (meth)acrylate having an alkyl group with 4 to 12 carbon atoms at the ester terminus. By including a structural unit derived from an alkyl (meth)acrylate having an alkyl group with 4 to 12 carbon atoms at the ester terminus, the glass transition temperature (Tg) of the (meth)acrylic copolymer is further lowered. As a result, the shear storage modulus at 25°C (measured at a frequency of 10 Hz in the dynamic viscoelasticity measurement of the first adhesive layer described below) (hereinafter sometimes referred to as the "shear storage modulus at 25°C of the first adhesive layer") is moderately reduced, further enhancing the flexibility of the first adhesive layer. This improves the adhesion of the first adhesive layer to the fluororesin and the adhesion to the substrate.

[0071] In addition, in this specification, "(meth)acrylate" means acrylate or methacrylate.

[0072] In the present specification, “alkyl (meth)acrylate having an alkyl group at the ester terminal” means a (meth)acrylate having an alkyl group bonded to the oxygen atom of the ester bond.

[0073] Examples of the alkyl (meth)acrylates having an alkyl group with 4 to 12 carbon atoms at the ester terminus include n-butyl (meth)acrylate, t-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. Of these, from the perspective of further improving the adhesive strength of the adhesive tape (particularly the adhesive strength to fluororesins), the alkyl (meth)acrylates having an alkyl group with 4 to 12 carbon atoms at the ester terminus preferably include those having an alkyl group with 6 to 8 carbon atoms at the ester terminus, and more preferably include n-heptyl (meth)acrylate. These 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.

[0074] Generally, alkyl (meth)acrylates containing an odd-numbered alkyl group at the ester end tend to be less likely to stack with each other, resulting in a lower glass transition temperature (Tg). Therefore, by including structural units derived from n-heptyl (meth)acrylate in the (meth)acrylic acid-based copolymer, stacking of the alkyl groups at the ester end of the (meth)acrylic acid-based copolymer can be further suppressed, further lowering the glass transition temperature (Tg) of the (meth)acrylic acid-based copolymer. As a result, the shear storage modulus at 25°C of the first adhesive layer, described below, is moderately reduced, further improving the flexibility of the first adhesive layer. This enhances the adhesion of the first adhesive layer to the fluororesin and further improves its adhesion to the substrate.

[0075] In the (meth)acrylic copolymer, the preferred lower limit of the content of structural units derived from an alkyl (meth)acrylate having an alkyl group with 4 to 12 carbon atoms at the ester terminal is 50% by mass. By increasing the content of structural units derived from an alkyl (meth)acrylate having an alkyl group with 4 to 12 carbon atoms at the ester terminal to 50% by mass or greater, the glass transition temperature (Tg) of the (meth)acrylic copolymer is further lowered. As a result, the shear storage modulus at 25°C of the adhesive layer described below is moderately reduced, further improving the flexibility of the first adhesive layer and, consequently, further enhancing adhesion to the substrate. The more preferred lower limit of the content of structural units derived from an alkyl (meth)acrylate having an alkyl group with 4 to 12 carbon atoms at the ester terminal is 90% by mass, and even more preferably, 95% by mass.

[0076] The upper limit of the content of the structural units derived from the alkyl (meth)acrylate having an alkyl group having 4 to 12 carbon atoms at the ester terminal can be 99.99% by mass. From the perspective of the overall cohesive force of the first adhesive layer, the upper limit is preferably 99% by mass.

[0077] In the (meth)acrylic copolymer, the preferred lower limit of the content of structural units derived from an alkyl (meth)acrylate having an alkyl group with 6 to 8 carbon atoms at the ester terminal is 50% by mass. By increasing the content of structural units derived from an alkyl (meth)acrylate having an alkyl group with 6 to 8 carbon atoms at the ester terminal to 50% by mass or greater, the glass transition temperature (Tg) of the (meth)acrylic copolymer is further lowered. As a result, the shear storage modulus at 25°C of the adhesive layer described below is moderately reduced, further improving the flexibility of the first adhesive layer and, consequently, further enhancing adhesion to the substrate. The more preferred lower limit of the content of structural units derived from an alkyl (meth)acrylate having an alkyl group with 6 to 8 carbon atoms at the ester terminal is 85% by mass, and even more preferably, 90% by mass.

[0078] From the viewpoint of the overall cohesive force of the first adhesive layer, the upper limit of the structural unit derived from the alkyl (meth)acrylate having an alkyl group having 4 to 12 carbon atoms at the ester terminal is preferably 99.5% by mass, and the more preferred upper limit is 99% by mass.

[0079] The aforementioned alkyl (meth)acrylates may include other alkyl (meth)acrylates other than the aforementioned alkyl (meth)acrylates having an alkyl group with 4 to 12 carbon atoms at the ester terminus. Examples of these other alkyl (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, myristyl (meth)acrylate, cetyl (meth)acrylate, stearyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, esters of 5,7,7-trimethyl-2-(1,3,3-trimethylbutyl)octanol-1 with (meth)acrylic acid, esters of alcohols with a total carbon number of 18 and having one or two methyl groups in a linear main chain with (meth)acrylic acid, behenyl (meth)acrylate, and eicosyl (meth)acrylate. These other alkyl (meth)acrylates may be used alone or in combination of two or more.

[0080] The (meth)acrylic acid-based copolymer preferably further comprises a structural unit derived from a monomer containing a polar functional group. By including a structural unit derived from a monomer containing a polar functional group in the (meth)acrylic acid-based copolymer, the overall cohesive force of the first adhesive layer is increased, further improving the adhesive strength and holding performance of the resulting adhesive tape.

[0081] The polar functional group has reactivity such as crosslinking reactions and is preferably at least one selected from a carboxyl group, a hydroxyl group, an amino group, and an epoxy group. Of these, one selected from a carboxyl group and a hydroxyl group is more preferred because it can further contribute to improving the adhesive strength and holding performance of the resulting adhesive tape. Specifically, the (meth)acrylic copolymer preferably comprises at least one structural unit selected from structural units derived from a carboxyl group-containing (meth)acrylate and structural units derived from a hydroxyl group-containing (meth)acrylate.

[0082] Examples of the carboxyl group-containing monomer include (meth)acrylic acid and the like.

[0083] Examples of the hydroxyl group-containing monomer include 4-hydroxybutyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 2-hydroxyethyl (meth)acrylate.

[0084] Examples of the epoxy group-containing monomer include glycidyl (meth)acrylate.

[0085] These polar functional group-containing monomers may be used alone or in combination of two or more.

[0086] In the (meth)acrylic acid copolymer, the preferred lower limit of the content of the structural units derived from the carboxyl group-containing monomer is 0.01% by mass, and the preferred upper limit is 7.0% by mass. By adjusting the content of the structural units derived from the carboxyl group-containing monomer within this range, the overall cohesive force of the first adhesive layer can be appropriately adjusted, thereby achieving even better adhesive strength and retention performance of the resulting adhesive tape. A more preferred lower limit of the content of the structural units derived from the carboxyl group-containing monomer is 0.05% by mass, and a more preferred upper limit is 5.0% by mass.

[0087] In the (meth)acrylic acid-based copolymer, the preferred lower limit of the content of structural units derived from the hydroxyl-containing monomer is 0.01% by mass, and the preferred upper limit is 3.0% by mass. By adjusting the content of structural units derived from the hydroxyl-containing monomer within this range, the overall cohesive force of the first adhesive layer can be appropriately adjusted, thereby further improving the adhesive strength and holding performance of the resulting adhesive tape. A more preferred lower limit of the content of structural units derived from the hydroxyl-containing monomer is 0.05% by mass, and a more preferred upper limit is 2.0% by mass.

[0088] In the (meth)acrylic copolymer, the total content of structural units derived from the polar functional group-containing monomer has a preferred lower limit of 0.01% by mass and a preferred upper limit of 10.0% by mass. By adjusting the total content of structural units derived from the polar functional group-containing monomer within this range, the overall cohesive force of the first adhesive layer can be appropriately adjusted, thereby further improving the adhesive strength and holding performance of the resulting adhesive tape. A more preferred lower limit of the total content of structural units derived from the polar functional group-containing monomer is 0.1% by mass, and a more preferred upper limit is 7.0% by mass.

[0089] The (meth)acrylic acid-based copolymer may, if necessary, contain structural units derived from other copolymerizable polymerizable monomers in addition to the structural units derived from the aforementioned alkyl (meth)acrylates and the structural units derived from the aforementioned polar functional group-containing monomers. Examples of these other monomers include benzyl (meth)acrylate, 2-butoxyethyl (meth)acrylate, 2-phenoxyethyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, and polypropylene glycol mono(meth)acrylate. Furthermore, various monomers commonly used in acrylic acid-based polymers, such as vinyl carboxylates such as vinyl acetate and styrene, may also be used as these other monomers. These other monomers may be used alone or in combination of two or more.

[0090] The preferred lower limit of the weight-average molecular weight (Mw) of the (meth)acrylic acid copolymer is 200,000, and the preferred upper limit is 2,000,000. By setting the weight-average molecular weight (Mw) of the (meth)acrylic acid copolymer to 200,000 or greater, the overall cohesive force of the first adhesive layer is enhanced, further improving the adhesive strength and holding performance of the resulting adhesive tape. By setting the weight-average molecular weight (Mw) of the (meth)acrylic acid copolymer to 2,000,000 or less, the adhesion of the first adhesive layer to the substrate is further improved. The more preferred lower limit of the weight-average molecular weight (Mw) of the (meth)acrylic acid copolymer is 300,000, the more preferred upper limit is 1,600,000, the further preferred lower limit is 500,000, and the further preferred upper limit is 1,200,000.

[0091] The ratio of the weight-average molecular weight (Mw) to the number-average molecular weight (Mn) of the (meth)acrylic copolymer (molecular weight distribution, Mw / Mn) preferably has a lower limit of 1.05 and an upper limit of 10.0. A molecular weight distribution (Mw / Mn) of 1.05 or greater for the (meth)acrylic copolymer further enhances the flexibility of the first adhesive layer, and the resulting adhesive tape exhibits enhanced adhesion to fluororesins. A molecular weight distribution (Mw / Mn) of 10.0 or less for the (meth)acrylic copolymer suppresses the proportion of low-molecular components, enhancing the overall cohesive force of the first adhesive layer and further improving the adhesive strength and holding performance of the resulting adhesive tape. A more preferred upper limit for the molecular weight distribution (Mw / Mn) of the (meth)acrylic copolymer is 8.0, a further preferred upper limit is 6.0, and an even more preferred upper limit is 4.0.

[0092] In this specification, weight-average molecular weight (Mw) and number-average molecular weight (Mn) refer to weight-average molecular weights measured in terms of standard polystyrene using gel permeation chromatography (GPC). Specifically, a (meth)acrylic acid copolymer is diluted 50-fold with tetrahydrofuran (THF), and the diluted solution is filtered through a filter (material: polytetrafluoroethylene, pore size: 0.2 μm). The resulting filtrate is fed to a gel permeation chromatograph (e.g., "2690 Separations Module" manufactured by Waters) for GPC measurement at a sample flow rate of 1 mL / min and a column temperature of 40°C. The polystyrene-equivalent molecular weight of the (meth)acrylic acid copolymer is measured to determine the weight-average molecular weight (Mw) and number-average molecular weight (Mn). For example, a GPC KF-802.5L (manufactured by Showa Denko K.K.) can be used as a column, and a differential refractometer can be used as a detector. Furthermore, the molecular weight distribution (Mw / Mn) can be determined using the obtained weight-average molecular weight (Mw) and number-average molecular weight (Mn).

[0093] To adjust the weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the (meth)acrylic copolymer to within the above ranges, for example, the composition, polymerization method, and polymerization conditions of the (meth)acrylic copolymer may be adjusted.

[0094] The glass transition temperature (Tg) of the (meth)acrylic copolymer preferably has a lower limit of -70°C and an upper limit of -30°C. By adjusting the glass transition temperature of the (meth)acrylic copolymer within this range, it is easier to adjust the shear storage modulus of the first adhesive layer (described later) at 25°C to an appropriate range, thereby further improving the adhesive strength and retention performance of the resulting adhesive tape with respect to fluororesin. The more preferred lower limit of the glass transition temperature (Tg) of the (meth)acrylic copolymer is -60°C, and the more preferred upper limit is -40°C.

[0095] In this specification, the glass transition temperature may be a value obtained by measuring using a differential scanning calorimeter (e.g., "SII Exstar 6000 / DSC6220" manufactured by Hitachi High-Tech Science Co., Ltd.) in a nitrogen atmosphere at a heating rate of 10°C / min, using the first run.

[0096] As a polymerization method for synthesizing the (meth)acrylic acid-based copolymer, a conventionally known method can be used in which monomers serving as sources of the structural units are subjected to a free radical reaction in the presence of a polymerization initiator. Examples thereof include solution polymerization (boiling point polymerization or constant temperature polymerization), emulsion polymerization, suspension polymerization, and bulk polymerization. Of these, solution polymerization is preferred due to its ease of synthesis.

[0097] When solution polymerization is used as the polymerization method, examples of the reaction solvent include ethyl acetate, toluene, methyl ethyl ketone, methyl sulfoxide, ethanol, acetone, diethyl ether, etc. These reaction solvents may be used alone or in combination of two or more.

[0098] Examples of the polymerization initiator include organic peroxides and azo compounds.

[0099] Examples of the organic peroxide include 1,1-bis(tert-hexylperoxy)-3,3,5-trimethylcyclohexane, tert-hexyl peroxypivalate, tert-butyl peroxypivalate, 2,5-dimethyl-2,5-bis(2-ethylhexanoylperoxy)hexane, tert-hexyl peroxy-2-ethylhexanoate, tert-butyl peroxy-2-ethylhexanoate, tert-butyl peroxyisobutyrate, tert-butyl peroxy-3,5,5-trimethylhexanoate, and tert-butyl peroxylaurate.

[0100] Examples of the azo compound include azobisisobutyronitrile and azobiscyclohexanecarbonitrile.

[0101] These polymerization initiators may be used alone or in combination of two or more.

[0102] The styrene-based elastomer may be a block copolymer having a block derived from the styrene-based monomer and a block derived from the conjugated diene-based monomer, exhibiting rubber elasticity at room temperature, and having a hard segment portion and a soft segment portion. It should be noted that the block derived from the styrene-based monomer is the hard segment portion, and the block derived from the conjugated diene-based monomer is the soft segment portion.

[0103] Examples of the styrene-based monomers include styrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, α-methylstyrene, 2,4-dimethylstyrene, 2,4-diisopropylstyrene, 4-tert-butylstyrene, 5-tert-butyl-2-methylstyrene, vinylethylbenzene, divinylbenzene, trivinylbenzene, divinylnaphthalene, tert-butoxystyrene, vinylbenzyldimethylamine, (4-vinylbenzyl)dimethylaminoethyl ether, N,N-dimethylaminoethylstyrene, N,N-dimethylaminomethylstyrene, 2-ethylstyrene, 3-ethylstyrene, 4-ethylstyrene, 2-tert-butylstyrene, 3-tert-butylstyrene, 4-tert-butylstyrene, vinylxylene, vinylnaphthalene, vinylpyridine, diphenylethylene, and tertiary amino group-containing diphenylethylene. Among these, styrene is preferred due to its industrial availability.

[0104] Examples of the tertiary amino group-containing diphenylethylene include 1-(4-N,N-dimethylaminophenyl)-1-phenylethylene.

[0105] These styrene-based monomers may be used alone or in combination of two or more.

[0106] Examples of the conjugated diene monomer include isoprene, 1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene, 1,3-heptadiene, 2-phenyl-1,3-butadiene, 3-methyl-1,3-pentadiene, and 2-chloro-1,3-butadiene. Among these, 1,3-butadiene and isoprene are preferred due to their high polymerization reactivity and industrial availability.

[0107] These conjugated diene monomers may be used alone or in combination of two or more.

[0108] Specific examples of the styrene-based elastomers include styrene-isoprene-styrene (SIS) block copolymers, styrene-butadiene-styrene (SBS) block copolymers, and styrene-chloroprene-styrene block copolymers. Among these, SIS block copolymers and SBS block copolymers are preferred, with SIS block copolymers being more preferred, as the resulting adhesive tape readily exhibits high adhesive strength and is less susceptible to peeling from the adherend even when immersed in an alkaline solution. These styrene-based elastomers may be used alone or in combination of two or more.

[0109] The styrene-based elastomer may contain a diblock copolymer of a block derived from the styrene-based monomer and a block derived from the conjugated diene-based monomer, in addition to a triblock copolymer of a block derived from the styrene-based monomer and a block derived from the conjugated diene-based monomer.

[0110] The preferred lower limit of the content of the diblock copolymer in the styrene-based elastomer (hereinafter sometimes referred to as the "diblock ratio") is 50% by mass. A diblock ratio of 50% or greater improves the adhesion of the first adhesive layer to the adherend, further enhancing the adhesive strength of the resulting adhesive tape. Furthermore, the shear storage modulus of the first adhesive layer at 25°C, described later, is moderately reduced, further enhancing the flexibility of the first adhesive layer. This improves the adhesion of the first adhesive layer to the fluororesin and further enhances its adhesion to the substrate. A more preferred lower limit of the diblock ratio is 70% by mass.

[0111] Furthermore, from the viewpoint of further improving the cohesive force of the first pressure-sensitive adhesive layer, the preferred upper limit of the diblock ratio is 90% by mass.

[0112] The diblock ratio can be calculated from the peak area ratio of each copolymer measured by gel permeation chromatography (GPC).

[0113] The preferred upper limit of the content of the block derived from the styrene monomer in the styrene-based elastomer (hereinafter sometimes referred to as "styrene content") is 20% by mass. By setting the styrene content to 20% by mass or less, the first adhesive layer does not become too hard, improving adhesion to the adherend and further enhancing the adhesive strength of the resulting adhesive tape. A more preferred upper limit of the styrene content is 16% by weight.

[0114] Furthermore, from the viewpoint of further improving the cohesive force of the first pressure-sensitive adhesive layer, a preferred lower limit of the styrene content is 8% by mass.

[0115] It should be noted that the above styrene content can be determined by 1The peak area ratio of each block measured by H-NMR was calculated.

[0116] The preferred lower limit of the weight average molecular weight of the styrene-based elastomer is 50,000, and the preferred upper limit is 600,000. By setting the weight average molecular weight of the styrene-based elastomer to 50,000 or more, the overall strength of the first adhesive layer is improved, and the adhesive force of the resulting adhesive tape is further improved. By setting the weight average molecular weight of the styrene-based elastomer to 600,000 or less, the compatibility of the styrene-based elastomer with other components is further improved. The more preferred lower limit of the weight average molecular weight of the styrene-based elastomer is 100,000, and the more preferred upper limit is 500,000.

[0117] The preferred lower limit of the content of the base polymer (P1) in the first adhesive layer is 30% by mass, and the preferred upper limit is 99.5% by mass. By setting the content of the base polymer (P1) within this range, the adhesion of the first adhesive layer to the fluororesin is further improved. A more preferred lower limit of the content of the base polymer (P1) is 40% by mass, a more preferred upper limit is 99% by mass, a further preferred lower limit is 50% by mass, and a further preferred upper limit is 95% by mass.

[0118] The adhesive layer contains a tackifying resin.

[0119] The tackifying resin preferably comprises a tackifying resin (T1) having at least one structural unit (A) 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), structural unit (A-3'), structural unit (A-4), and structural unit (A-4') represented by the above formula. Including the tackifying resin (T1) in the first adhesive layer allows the first adhesive layer to exhibit higher adhesive strength, particularly to adherends with low polarity (e.g., fluororesins), and further improves adhesion to the substrate.

[0120] Among these, from the perspective of significantly improving the interaction with the adherend and further enhancing the adhesive strength to the adherend, the structural unit (A) is preferably at least one selected from the structural unit (A-1), the structural unit (A-1'), the structural unit (A-2), the structural unit (A-2'), the structural unit (A-3), and the structural unit (A-3'), and more preferably at least one selected from the structural unit (A-1) and the structural unit (A-1'). By using at least one selected from the structural unit (A-1) and the structural unit (A-1') as the structural unit (A), the interaction with the adherend can be further significantly improved. Furthermore, since monomers comprising bio-derived materials, as described later, can be readily used as monomers constituting the structural units (A-1) and (A-1'), this is preferred from the perspective of conserving petroleum resources. Furthermore, when the base polymer (P1) is a (meth)acrylic acid-based copolymer, the tackifier resin (T1) has an appropriate polarity, thereby further improving its compatibility with the (meth)acrylic acid-based copolymer.

[0121] The tackifying resin (T1) may have the structural unit (A) in a side chain, in the main chain, or at a terminal of the main chain. However, from the perspective of achieving suitable physical properties required for a tackifying resin, the tackifying resin (T1) preferably has the structural unit (A) in the main chain or at a terminal of the main chain.

[0122] In the above structural unit (A), R 1 ~R 7 They respectively represent a hydrogen atom, an aliphatic hydrocarbon group, an aromatic hydrocarbon group, a polar functional group, an aliphatic hydrocarbon group having a polar functional group, or an aromatic hydrocarbon group having a polar functional group.

[0123] Examples of the aliphatic hydrocarbon group include linear, branched, or cyclic alkyl groups having 1 to 20 carbon atoms, and examples of the aromatic hydrocarbon group include substituted or unsubstituted aryl groups having 1 to 20 carbon atoms.

[0124] The polar functional group is not particularly limited. 1 , polar functional groups other than hydroxyl groups can be used as R 2 , polar functional groups other than carboxyl can be used as R 3 , you can use OR 4 Polar functional groups other than those shown in the figure, as R 5 , you can use NR 6 R 7Polar functional groups other than the groups shown in . Specific examples of the polar functional groups include amino groups, carboxyl groups, carbonyl groups, alkoxy groups, hydroxyl groups, nitrile groups, and nitro groups.

[0125] As the aliphatic hydrocarbon group having a polar functional group, for example, a group in which one or more hydrogen atoms in the above-mentioned aliphatic hydrocarbon group are replaced by the above-mentioned polar functional group can be used. As the aromatic hydrocarbon group having a polar functional group, for example, a group in which one or more hydrogen atoms in the above-mentioned aromatic hydrocarbon group are replaced by the above-mentioned polar functional group can be used.

[0126] It should be noted that in the above-mentioned tackifying resin (T1), the multiple R 1 They may be the same or different. In addition, the multiple R contained in different structural units (A-1) 1 Similarly, the plurality of R contained in one structural unit (A-1') may be the same or different. 1 They may be the same or different. In addition, the multiple R contained in different structural units (A-1') 1 They can be the same or different.

[0127] Similarly, a plurality of R contained in one structural unit (A-2) 2 They may be the same or different. In addition, the multiple R contained in different structural units (A-2) 2 Similarly, the plurality of R contained in one structural unit (A-2') may be the same or different. 2 They may be the same or different. In addition, the multiple R contained in different structural units (A-2') 2 They can be the same or different.

[0128] Similarly, multiple R contained in one structural unit (A-3) 3 They may be the same or different. In addition, the multiple R contained in different structural units (A-3) 3 Similarly, the multiple R contained in one structural unit (A-3') 3 They may be the same or different. In addition, the multiple R contained in different structural units (A-3') 3 They can be the same or different.

[0129] Similarly, multiple R contained in one structural unit (A-3) 4 They may be the same or different. In addition, the multiple R contained in different structural units (A-3) 4Similarly, the multiple R contained in one structural unit (A-3') 4 They may be the same or different. In addition, the multiple R contained in different structural units (A-3') 4 They can be the same or different.

[0130] Similarly, a plurality of R contained in one structural unit (A-4) 5 They may be the same or different. In addition, the multiple R contained in different structural units (A-4) 5 Similarly, the plurality of R contained in one structural unit (A-4') may be the same or different. 5 They may be the same or different. In addition, the multiple R contained in different structural units (A-4') 5 They can be the same or different.

[0131] Similarly, a plurality of R contained in one structural unit (A-4) 6 and R 7 They may be the same or different. In addition, the multiple R contained in different structural units (A-4) 6 and R 7 Similarly, the plurality of R contained in one structural unit (A-4') may be the same or different. 6 and R 7 They may be the same or different. In addition, the multiple R contained in different structural units (A-4') 6 and R 7 They can be the same or different.

[0132] In the structural unit (A), n and l are each an integer of 2 to 4, and n' and l' are each an integer of 2 to 5, without particular limitation. From the viewpoint of easy availability of raw materials, n, l, n', and l' are preferably 2 or 3. From the viewpoint of further improving the adhesive strength of the first adhesive layer, n, l, n', and l' are more preferably 3.

[0133] In the structural unit (A), m and k are each an integer from 1 to 4, and m' and k' are each an integer from 1 to 5, and are not particularly limited. From the perspective of easy availability of raw materials, m, k, m', and k' are preferably 1, 2, or 3. From the perspective of further improving the adhesive strength of the first adhesive layer, m, k, m', and k' are more preferably 1.

[0134] More specific examples of the structural unit (A-1) and the structural unit (A-1') include a structural unit derived from dihydroxybenzene or a derivative thereof (when n and n' are 2), a structural unit derived from trihydroxybenzene or a derivative thereof (when n and n' are 3), etc. These structural units may be used alone or in combination of two or more.

[0135] Examples of the dihydroxybenzenes or their derivatives include resorcinol, catechol, hydroquinone, dihydroxytoluene, dihydroxyxylene, dihydroxyphenylethylamine hydrochloride, dihydroxybenzoic acid, dihydroxyphenylacetic acid, dihydroxyhydrocinnamic acid, dihydroxyphenylpropionic acid, dihydroxyphenylalanine, dihydroxybenzaldehyde, dihydroxyacetophenone, diacetyldihydroxybenzene, dihydroxyphenyl-2-butanone, dihydroxyphenylacetic acid methyl ester, benzyldihydroxyphenyl ketone, dihydroxybenzamide, dihydroxymethoxybenzene, dihydroxybenzyl alcohol, dihydroxyphenylethanol, dihydroxyphenyl glycol, dihydroxyphenylacetonitrile, and dihydroxynitrobenzene. Of these, catechol is preferred because it has little steric hindrance and readily interacts with an adherend. These dihydroxybenzenes or their derivatives may be used alone or in combination of two or more.

[0136] Examples of the 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, cetyl gallate, stearyl gallate, trihydroxyacetophenone, trihydroxyphenylacetone, trihydroxyphenylbutanone, trihydroxybenzaldehyde, trihydroxybenzamide, and trihydroxynitrobenzene. Of these, pyrogallol is preferred due to its low steric hindrance and ease of interaction with adherends. These trihydroxybenzenes or their derivatives may be used alone or in combination of two or more.

[0137] More specific examples of the structural units (A-2) and (A-2') include those derived from benzoic acid, salicylic acid, dihydroxybenzoic acid, gallic acid, 2-methylbenzoic acid, 3-methylbenzoic acid, 4-methylbenzoic acid, 2-ethylbenzoic acid, 3-ethylbenzoic acid, 4-ethylbenzoic acid, 4-tert-butylbenzoic acid, 2-vinylbenzoic acid, 3-vinylbenzoic acid, 4-vinylbenzoic acid, 4,4'-stilbene dicarboxylic acid, and derivatives thereof. Among them, 4-vinylbenzoic acid is preferred due to its low steric hindrance and ease of interaction with the adherend. These structural units may be used alone or in combination of two or more.

[0138] More specific examples of the structural unit (A-3) and the structural unit (A-3′) include a structural unit derived from dialkoxybenzene or a derivative thereof (when l and l′ are 2), and a structural unit derived from trialkoxybenzene or a derivative thereof (when l and l′ are 3).

[0139] Examples of the dialkoxybenzene or its derivatives include 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, and 1,4-dimethoxybenzene. Examples of the 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 due to its low steric hindrance and ease of interaction with adherends. These trialkoxybenzenes or their derivatives may be used alone or in combination of two or more.

[0140] More specifically, examples of the structural units (A-4) and (A-4') include structural units derived from aminobenzene or its derivatives (when k and k' are 1). Examples of the aminobenzene or its derivatives include aniline, methylaniline, ethylaniline, dimethylaniline, and diethylaniline. These aminobenzenes or their derivatives may be used alone or in combination of two or more.

[0141] The structural unit (A) may be composed solely of petroleum-derived materials, but preferably includes biologically derived materials. The depletion of petroleum resources and the emission of carbon dioxide from the combustion of petroleum-derived products are considered problematic. Therefore, attempts are being made to conserve petroleum resources by replacing petroleum-derived materials with biologically derived materials. If the structural unit (A) includes biologically derived materials, this is preferred from the perspective of conserving petroleum resources. Furthermore, if the structural unit (A) includes biologically derived materials, since biologically derived materials are originally produced by absorbing carbon dioxide from the atmosphere, even if they are burned, the total amount of carbon dioxide in the atmosphere will not increase, which is also preferred from the perspective of reducing carbon dioxide emissions.

[0142] Examples of the monomer constituting the structural unit (A) containing a bio-derived material include resorcinol, dihydroxyphenylethylamine hydrochloride, dihydroxyhydrocinnamic acid, dihydroxyphenylalanine, dihydroxybenzaldehyde, dihydroxybenzyl alcohol, pyrogallol, 1,2,4-trihydroxybenzene, phloroglucinol, 6-hydroxy-L-dopa, gallic acid, methyl gallate, butyl gallate, isobutyl gallate, isoamyl gallate, cetyl gallate, stearyl gallate, trihydroxyacetophenone, trihydroxybenzaldehyde, trihydroxybenzamide, and trihydroxynitrobenzene.

[0143] The content (on a molar basis) of the structural unit (A) in the tackifier resin (T1) is not particularly limited, but the preferred lower limit is 1 mol% and the preferred upper limit is 60 mol%. If the content of the structural unit (A) is 1 mol% or greater, the adhesive strength of the first adhesive layer can be further enhanced by adding the tackifier resin (T1). If the content of the structural unit (A) is 60 mol% or less, the tackifier resin (T1) can possess the appropriate physical properties required for a tackifier resin. The more preferred lower limit of the content of the structural unit (A) is 5 mol%, the more preferred upper limit is 50 mol%, the further preferred lower limit is 10 mol%, and the further preferred upper limit is 30 mol%.

[0144] The content (by mass) of the structural unit (A) in the tackifier resin (T1) is not particularly limited, but the preferred lower limit is 0.9% by mass and the preferred upper limit is 60% by mass. If the content of the structural unit (A) is 0.9% by mass or greater, the adhesive strength of the first adhesive layer can be further enhanced by adding the tackifier resin (T1). If the content of the structural unit (A) is 60% by mass or less, the tackifier resin (T1) can possess the appropriate physical properties required for a tackifier resin. The more preferred lower limit of the content of the structural unit (A) is 5% by mass, the more preferred upper limit is 50% by mass, the further preferred lower limit is 10% by mass, and the further preferred upper limit is 30% by mass.

[0145] The tackifier resin (T1) preferably further comprises a structural unit (B) derived from at least one monomer (b) selected from a terpene-based monomer and a vinyl-based monomer. The tackifier resin (T1) comprising the structural unit (B) can thereby possess the desired physical properties required of a tackifier resin.

[0146] Among these, structural units derived from terpene monomers or structural units derived from vinyl monomers are preferred from the perspective of further improving the adhesive strength of the first adhesive layer. A combination of structural units derived from terpene monomers and structural units derived from vinyl monomers is also preferred. Furthermore, structural units derived from terpene monomers are preferred from the perspective of improving the compatibility of the tackifier resin (T1) with the base polymer. Since structural units derived from terpene monomers have aliphatic hydrocarbon groups having unsaturated double bonds, the inclusion of structural units derived from terpene monomers in the tackifier resin (T1) improves the compatibility of the tackifier resin (T1) with the base polymer, thereby suppressing a decrease in the adhesive strength of the first adhesive layer due to a decrease in compatibility.

[0147] Examples of the terpene monomer include α-pinene, β-pinene, limonene, dipentene, δ-3-carene, dimethyloctatriene, alloocimene, myrcene, ocimene, linalool, and cosmene. Among these, α-pinene, β-pinene, and limonene are preferred because they can further enhance the adhesive strength of the first adhesive layer.

[0148] The vinyl monomer is not particularly limited. From the perspective of improving the compatibility between the tackifier resin (T1) and the base polymer, it is preferably a vinyl monomer that does not have a structure containing two or more aromatic rings per molecule (e.g., a naphthalene structure, anthracene structure, biphenyl structure, anthraquinone structure, or benzophenone structure). Examples of the vinyl monomer that does not have a structure containing two or more aromatic rings per molecule include ethylene, propylene, butene, hexene, vinyl acetate, vinyl chloride, styrene, α-methylstyrene, coumarone, indene, vinyltoluene, divinylbenzene, divinyltoluene, and 2-phenyl-2-butene. Among these, styrene is preferred from the perspective of further improving the adhesive strength of the first adhesive layer.

[0149] These monomers (b) may be used alone or in combination of two or more.

[0150] The structural unit (B) may be composed solely of petroleum-derived materials, but preferably includes biologically derived materials. The depletion of petroleum resources and the emission of carbon dioxide from the combustion of petroleum-derived products are considered problematic. Therefore, attempts are being made to conserve petroleum resources by replacing petroleum-derived materials with biologically derived materials. If the structural unit (B) includes biologically derived materials, this is preferred from the perspective of conserving petroleum resources. Furthermore, if the structural unit (B) includes biologically derived materials, since biologically derived materials are originally produced by absorbing carbon dioxide from the atmosphere, even if they are burned, the total amount of carbon dioxide in the atmosphere will not increase, which is also preferred from the perspective of reducing carbon dioxide emissions.

[0151] Examples of the monomer (b) constituting the structural unit (B) containing a bio-derived material include terpene monomers, ethylene, propylene, and hexene.

[0152] The preferred lower limit of the content of the structural unit (B) in the tackifying resin (T1) is 40 mol%, and the preferred upper limit is 99 mol%. When the content of the structural unit (B) is 40 mol% or greater, the tackifying resin (T1) can possess the appropriate physical properties required for a tackifying resin. When the content of the structural unit (B) is 99 mol% or less, the content of the structural unit (A) can be sufficiently maintained, thereby further improving the adhesive strength of the first adhesive layer, particularly even to adherends with low polarity. The more preferred lower limit of the content of the structural unit (B) is 50 mol%, and the more preferred upper limit is 90 mol%.

[0153] The tackifier resin (T1) is not particularly limited as long as it is a compound containing the structural unit (A), but is preferably a copolymer having a structure represented by the following formula. When the structural unit (A) is present in the main chain or at a terminal of the main chain, the copolymer preferably has a structure represented by the following formula.

[0154] A copolymer having such a structure is obtained by a method using cationic polymerization as described below, and can further enhance the adhesive strength of the first pressure-sensitive adhesive layer, particularly to adherends having low polarity.

[0155] [Chemical Formula 5]

[0156]

[0157] In the formula, A represents a structural unit (A), B represents a structural unit (B), and s and t each represent an integer greater than 1. Indicates a connection part.

[0158] The tackifier resin (T1) is not particularly limited as long as it is a compound containing the structural unit (A). It is preferably a copolymer containing the structural unit (A) and the structural unit (B), and may further contain other structural units. In the case of a copolymer, the structural unit (A) and the structural unit (B) may be copolymerized randomly, or may be copolymerized regularly or periodically, for example, as in the case where each structural unit forms a block segment and the block segments are bonded to each other.

[0159] The tackifier resin (T1) preferably has an aliphatic hydrocarbon group having an unsaturated double bond. The tackifier resin (T1) may have the aliphatic hydrocarbon group having an unsaturated double bond in the structural unit (A) or the structural unit (B), or in another structural unit. From the perspective of ease of synthesis and improved compatibility between the tackifier resin (T1) and the base polymer, particularly between the tackifier resin (T1) and the styrene elastomer, it is preferred that the aliphatic hydrocarbon group having an unsaturated double bond be present in the structural unit (B) or another structural unit. The structural unit (B) or another structural unit containing the aliphatic hydrocarbon group having an unsaturated double bond is not particularly limited, but is preferably a structural unit (B) derived from at least one monomer (b) selected from a terpene-based monomer and a vinyl-based monomer. Specifically, the tackifier resin (T1) preferably contains the aforementioned aliphatic hydrocarbon group having an unsaturated double bond in the structural unit (B) derived from at least one monomer (b) selected from a terpene-based monomer and a vinyl-based monomer. In particular, from the perspective of further improving the adhesive strength of the first adhesive layer, it is preferred that the structural unit derived from a terpene-based monomer contain the aforementioned aliphatic hydrocarbon group having an unsaturated double bond.

[0160] Moreover, as said other structural unit, the structural unit derived from other phenolic monomers which are not contained in said structural unit (A), the structural unit derived from maleic anhydride, etc. are mentioned, for example.

[0161] Examples of the other phenolic monomers include phenol, cresol, xylenol, propylphenol, nonylphenol, methoxyphenol, bromophenol, bisphenol A, bisphenol F, bisphenol S, and dihydroxynaphthalene. These other phenolic monomers may be used alone or in combination of two or more.

[0162] The molecular weight of the tackifier resin (T1) is not particularly limited; however, the preferred lower limit of the weight-average molecular weight (Mw) is 400, and the preferred upper limit is 10,000. When the weight-average molecular weight (Mw) of the tackifier resin (T1) is within this range, the tackifier resin (T1) can possess the appropriate physical properties required for a tackifier resin. The more preferred lower limit of the weight-average molecular weight (Mw) of the tackifier resin (T1) is 500, the more preferred upper limit is 5000, the further preferred lower limit is 550, and the further preferred upper limit is 3000.

[0163] In order to adjust the weight average molecular weight (Mw) to the above range, for example, the composition of the tackifier resin (T1), the polymerization method, the polymerization conditions, etc. may be adjusted.

[0164] The preferred lower limit of the Young's modulus of the tackifier resin (T1) at 25°C is 10 MPa. By setting the Young's modulus of the tackifier resin (T1) at 25°C to 10 MPa or greater, the tackifier resin (T1) has appropriate hardness and can possess the appropriate physical properties required for a tackifier resin. The more preferred lower limit of the Young's modulus of the tackifier resin (T1) at 25°C is 50 MPa, and even more preferably 70 MPa.

[0165] Furthermore, from the viewpoint of preventing the first adhesive layer from becoming too hard and thus reducing adhesive strength, the upper limit of the Young's modulus of the tackifier resin (T1) at 25° C. is preferably 10,000 MPa, and more preferably 5,000 MPa.

[0166] The Young's modulus of the tackifier resin (T1) at 25°C can be measured by conducting a tensile test using a tensile testing apparatus (e.g., "Tensilon" manufactured by ORIENTEC Corporation) at a tensile speed of 200 mm / min, a distance between the grips of 15 mm, and a temperature of 25°C. The test sample can be obtained, for example, by filling a 10×50 mm mold with the tackifier resin (T1) and melting it at a temperature 100°C higher than the glass transition temperature to prepare a test piece having a thickness of 1 mm.

[0167] In order to adjust the Young's modulus of the tackifier resin (T1) at 25°C to within the above range, for example, the molecular weight and weight average molecular weight of the tackifier resin (T1), and the composition and content of the structural unit (A) and the structural unit (B) in the tackifier resin (T1) may be adjusted.

[0168] The preferred lower limit of the glass transition temperature of the tackifier resin (T1) is 0°C, and the preferred upper limit is 200°C. When the glass transition temperature of the tackifier resin (T1) is within this range, it is easy to adjust the Young's modulus of the tackifier resin (T1) at 25°C to within this range, thereby enabling the tackifier resin (T1) to have the appropriate physical properties required. The more preferred lower limit of the glass transition temperature of the tackifier resin (T1) is 10°C, and the more preferred upper limit is 150°C.

[0169] The preferred lower limit of the iodine value of the tackifier resin (T1) is 2 g / 100 g, and the preferred upper limit is 180 g / 100 g. By setting the iodine value of the tackifier resin (T1) to 2 g / 100 g or higher, it is possible to suppress a decrease in the adhesive strength of the first adhesive layer due to a decrease in compatibility between the tackifier resin (T1) and the base polymer. By setting the iodine value of the tackifier resin (T1) to 180 g / 100 g or lower, the adhesive strength of the first adhesive layer can be further improved, particularly for adherends with low polarity. The more preferred lower limit of the iodine value of the tackifier resin (T1) is 70 g / 100 g, and the more preferred upper limit is 170 g / 100 g.

[0170] The iodine value is an index indicating the amount of unsaturated double bonds (C═C bond amount), and is a value measured according to the method described in “JIS K0070:1992”.

[0171] The preferred lower limit of the content of biogenic carbon (carbon atoms) in the carbon (carbon atoms) of the tackifier resin (T1) is 10%. A biogenic carbon content of 10% or more is considered a "bio-based product."

[0172] A biogenic carbon content of 10% or greater in the tackifying resin (T1) is preferred from the perspectives of conserving petroleum resources and reducing carbon dioxide emissions. The more preferred lower limit of the biogenic carbon content in the tackifying resin (T1) is 30%, an even more preferred lower limit is 60%, an even more preferred lower limit is 70%, and an especially preferred lower limit is 90%. The upper limit of the biogenic carbon content in the tackifying resin (T1) is not particularly limited and may be 100%.

[0173] It should be noted that biogenic carbon contains a certain percentage of the radioactive isotope (C-14), whereas petroleum-derived carbon contains almost no C-14. Therefore, the biogenic carbon content of the tackifier resin (T1) can be calculated by measuring the C-14 concentration in the compound. Specifically, this can be measured according to ASTM D6866-22, a standard used in many bioplastics industries.

[0174] The tackifying resin (T1) may also contain a hydride of the aforementioned compound. It should be noted that the hydride refers to a compound obtained by at least partially saturating the carbon-carbon double bonds present in the tackifying resin (T1) through hydrogenation. That is, the first adhesive layer may contain a hydride in which some of the carbon-carbon double bonds in the tackifying resin (T1) are hydrogenated, or a hydride in which all of the carbon-carbon double bonds in the tackifying resin (T1) are hydrogenated. Even such hydrides are suitable for use as a tackifying resin in the first adhesive layer, and can enhance the adhesive strength of the first adhesive layer, particularly to adherends with low polarity.

[0175] The method for producing the tackifier resin (T1) is not particularly limited. However, when the structural unit (A) is present in the main chain or at a terminal of the main chain, the following method is preferred, for example: a method in which a monomer (a) constituting the structural unit (A) is copolymerized with at least one monomer (b) selected from a terpene-based monomer and a vinyl-based monomer constituting the structural unit (B) (hereinafter also referred to as production method [I]).

[0176] The monomer (a) is preferably at least one selected from the group consisting of monomer (a-1), monomer (a-2), monomer (a-3), and monomer (a-4) represented by the following formula.

[0177] [Chemical Formula 6]

[0178]

[0179] [Chemical Formula 7]

[0180]

[0181] [Chemical Formula 8]

[0182]

[0183] [Chemical Formula 9]

[0184]

[0185] In formulas (a-1) to (a-4), R 1 ~R 7 Each of n' 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 from 2 to 5, preferably 2 or 3, more preferably 3. m' represents an integer from 1 to 5. l' represents an integer from 2 to 5. k' represents an integer from 1 to 5.

[0186] In the method [I] for producing the tackifier resin (T1), it is preferred that the monomer (a) and the monomer (b) be copolymerized by cationic polymerization.

[0187] By using cationic polymerization, 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 unnecessary. Therefore, monomer (a) and monomer (b) can be copolymerized in a simpler, single-step reaction process, which also leads to reduced impurities and improved yield.

[0188] A preferred method for copolymerizing the monomer (a) and the monomer (b) by cationic polymerization is to react the monomers (a) and (b) in the presence of a Lewis acid. This method is believed to generate cations of the monomer (b), allowing cationic polymerization of the monomers (b) to proceed, while also allowing the Fridel-Crafts alkylation reaction between the monomers (a) and (b) to proceed. By repeating these reactions, a copolymer having structural units (A) derived from the monomer (a) and structural units (B) derived from the monomer (b) can be obtained.

[0189] The Lewis acid is not particularly limited, and conventionally known Lewis acids can be used. Examples thereof include 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 can produce a higher yield of copolymers.

[0190] More specifically, for example, when pyrogallol is used as the monomer (a) and α-pinene is used as the monomer (b), and these are reacted in the presence of aluminum chloride (AlCl 3 ) as a Lewis acid, the reaction shown in the following scheme is considered to proceed.

[0191] Specifically, cations of α-pinene (monomer (b)) are generated, and cationic polymerization of the α-pinenes proceeds (the upper section of the following scheme). Furthermore, a Fridel-Crafts alkylation reaction between pyrogallol (monomer (a)) and α-pinene (monomer (b)) proceeds (the middle section of the following scheme). By repeating these reactions, a copolymer having structural units derived from pyrogallol and structural units derived from α-pinene can be obtained (the lower section of the following scheme). It should be noted that such a copolymer contains structural units derived from pyrogallol within the main chain or at the ends of the main chain.

[0192] [Chemical Formula 10]

[0193]

[0194] In the formula, s and t each represent an integer greater than 1. Indicates a connection part.

[0195] When the tackifier resin (T1) has the structural unit (A) in a side chain, the following method is preferred, for example. Specifically, a method is preferred in which a monomer (a') further comprising an unsaturated double bond introduced into the monomer (a) constituting the structural unit (A) is copolymerized with at least one monomer (b) selected from a terpene-based monomer and a vinyl-based monomer constituting the structural unit (B) (hereinafter also referred to as production method [II]).

[0196] Examples of the monomer (a') include 2-vinylbenzoic acid, 3-vinylbenzoic acid, 4-vinylbenzoic acid, and 4,4'-stilbene dicarboxylic acid. Among these, 4-vinylbenzoic acid is preferred due to its low steric hindrance and ease of interaction with the adherend. These monomers (a') may be used alone or in combination of two or more.

[0197] In the method [II] for producing the tackifier resin (T1), it is also preferred that the monomer (a′) and the monomer (b) be copolymerized by cationic polymerization in the same manner as in the method [I] for producing the tackifier resin (T1).

[0198] A preferred method for copolymerizing the monomer (a') and the monomer (b) by cationic polymerization is to react the monomer (a') and the monomer (b) in the presence of a Lewis acid as described above. This method allows cationic polymerization of the unsaturated double bonds in the monomer (a') and the unsaturated double bonds in the monomer (b) to proceed, yielding a copolymer having structural units (A) derived from the monomer (a') and structural units (B) derived from the monomer (b).

[0199] The tackifier resin (T1) can improve the adhesive strength of the first adhesive layer even when used in a smaller amount compared to conventional tackifier resins. The preferred lower limit of the tackifier resin (T1) content per 100 parts by mass of the base polymer (P1) is 5 parts by mass, and the preferred upper limit is 50 parts by mass. By increasing the tackifier resin (T1) content to 5 parts by mass or greater, the adhesive strength of the first adhesive layer can be further improved, particularly for adherends with low polarity (such as fluororesins). By decreasing the tackifier resin (T1) content to 50 parts by mass or less, the first adhesive layer can be prevented from becoming excessively hard and thus reducing its adhesive strength. The more preferred lower limit of the tackifier resin (T1) content is 10 parts by mass, and the more preferred upper limit is 35 parts by mass.

[0200] The tackifying resin preferably includes at least one tackifying resin (T2) selected from rosin ester resins, terpene resins, terpene phenol resins, and petroleum resins. Including the tackifying resin (T2) further enhances the adhesive strength of the resulting adhesive tape.

[0201] Rosin ester resins are obtained by esterifying rosin resins primarily composed of abietic acid, disproportionated rosin resins, hydrogenated rosin resins, dimers of resin acids such as abietic acid (polymerized rosin resins), and the like with alcohols. The hydroxyl value is adjusted to the above range by allowing some of the hydroxyl groups of the alcohol used in the esterification to remain within the resin without being used for esterification. Examples of alcohols include polyols such as ethylene glycol, glycerin, and pentaerythritol.

[0202] Examples of the rosin ester resin include Pine Crystal KE-359, Ester Gum AA-V, and Ester Gum H (all manufactured by Arakawa Chemical Industries, Ltd.).

[0203] The terpene-based resin is a resin having a structural unit derived from a monoterpene compound and having no structural unit derived from an aromatic compound.

[0204] Examples of the terpene-based resin include YS Resin PX1250 (manufactured by Yasuhara Chemical Co., Ltd.).

[0205] The terpene-phenol resin is a resin comprising structural units derived from a monoterpene compound and structural units derived from a phenol compound. It should be noted that, as used herein, the term "phenol compound" in the terpene-phenol resin refers to a compound containing an aromatic ring structure having only one phenolic hydroxyl group and excluding aromatic ring structures having two or more phenolic hydroxyl groups. The structural units (A-1) and (A-1') described above are not structural units derived from phenol compounds in the terpene-phenol resin.

[0206] Examples of the terpene phenol resin include YS Polyster G150 (manufactured by Yasuhara Chemical Co., Ltd.).

[0207] Examples of the petroleum-based resin include Arkon P-140 (manufactured by Arakawa Chemical Industries, Ltd.).

[0208] The preferred lower limit for the softening temperature of the tackifier resin (T2) is 50°C, and the preferred upper limit is 200°C. By setting the softening temperature of the tackifier resin (T2) to 50°C or higher, the first adhesive layer can be prevented from becoming excessively soft and thus experiencing a decrease in adhesive strength. Setting the softening temperature of the tackifier resin (T2) to 200°C or lower improves the wettability of the interface of the first adhesive layer, thereby preventing interfacial delamination. Furthermore, the glass transition temperature (Tg) of the (meth)acrylic copolymer is further lowered. As a result, the shear storage modulus of the first adhesive layer (described later) at 25°C is moderately reduced, further improving the flexibility of the first adhesive layer. This enhances the adhesive strength of the first adhesive layer to the fluororesin and the adhesion to the substrate. The more preferred lower limit for the softening temperature of the tackifier resin (T2) is 60°C, the more preferred upper limit is 150°C, the further preferred lower limit is 70°C, and the further preferred upper limit is 90°C.

[0209] In addition, the softening temperature means the softening temperature measured by JIS K2207 (ring and ball method).

[0210] The hydroxyl value of the tackifier resin (T2) preferably has a lower limit of 0 mgKOH / g and an upper limit of 200 mgKOH / g. By setting the hydroxyl value of the tackifier resin (T2) within this range, wettability of the interface of the first adhesive layer is improved, thereby suppressing interfacial delamination. The more preferred lower limit of the hydroxyl value of the tackifier resin (T2) is 30 mgKOH / g, and the more preferred upper limit is 130 mgKOH / g.

[0211] In addition, the hydroxyl value can be measured according to JIS K1557 (phthalic anhydride method).

[0212] The preferred lower limit of the tackifier resin (T2) content per 100 parts by mass of the base polymer (P1) is 10 parts by mass, and the preferred upper limit is 200 parts by mass. When the tackifier resin (T2) content is 10 parts by mass or greater, the adhesive strength of the first adhesive layer can be further enhanced. When the tackifier resin (T2) content is 200 parts by mass or less, excessive hardening of the first adhesive layer, which could result in a decrease in adhesive strength, can be prevented. The more preferred lower limit of the tackifier resin (T2) content is 15 parts by mass, the more preferred upper limit is 160 parts by mass, the further preferred upper limit is 50 parts by mass, and the further preferred upper limit is 140 parts by mass.

[0213] To further reduce the contamination of the adherend by the adhesive tape, the first adhesive layer preferably contains no organosilicon compound, or the organosilicon compound content in the first adhesive layer is 3.0% by mass or less. If the first adhesive layer contains the organosilicon compound, the more preferred upper limit of the content is 1.0% by mass. It is particularly preferred that the first adhesive layer contain no organosilicon compound.

[0214] In this specification, the organosilicon compound is not particularly limited as long as it is an organic compound containing a silicon atom, and examples thereof include commercially available organosilicon adhesives, silane coupling agents, silicone oils, and the like.

[0215] When the base polymer (P1) comprises a (meth)acrylic acid copolymer, the first adhesive layer preferably further contains a curing agent. The inclusion of a curing agent in the first adhesive allows the (meth)acrylic acid copolymer to form a structure crosslinked by chemical crosslinking. This further enhances the overall cohesive force of the first adhesive layer and increases the gel fraction of the first adhesive layer, described below. This further improves the adhesive force and holding performance of the resulting adhesive tape.

[0216] Examples of the curing agent include isocyanate curing agents, aziridine curing agents, epoxy curing agents, and metal chelate curing agents. Among them, the first adhesive layer preferably contains an isocyanate curing agent from the viewpoint of enabling appropriate chemical crosslinking of the (meth)acrylic copolymer and further improving the adhesive strength and holding performance of the resulting adhesive tape.

[0217] Examples of the isocyanate curing agent include Coronate L-45 (manufactured by Tosoh Corporation), Takenate 500 (manufactured by Mitsui Chemicals, Inc.), and Desmodur L-75 (manufactured by Covestro Corporation).

[0218] The preferred lower limit of the curing agent content per 100 parts by mass of the (meth)acrylic copolymer is 0.01 parts by mass, and the preferred upper limit is 10 parts by mass. By adjusting the curing agent content within this range, appropriate chemical crosslinking of the (meth)acrylic copolymer can be achieved, further improving the adhesive strength and holding performance of the resulting adhesive tape. A more preferred lower limit of the curing agent content is 0.1 parts by mass, a more preferred upper limit is 5.0 parts by mass, an even more preferred lower limit is 0.5 parts by mass, and an even more preferred upper limit is 2.0 parts by mass.

[0219] For the purpose of imparting light-shielding properties, the first adhesive layer may further contain a coloring material. Examples of the coloring material include carbon black, aniline black, and titanium oxide. Among these, carbon black is preferred due to its relative low cost and chemical stability.

[0220] The first adhesive layer may contain conventionally known fine particles and additives such as inorganic fine particles, conductive fine particles, an antioxidant, a foaming agent, an organic filler, and an inorganic filler, as needed.

[0221] The preferred lower limit of the 180° peel strength of the first adhesive layer relative to the substrate at 23°C is 2.5 N / 25 mm. By setting the 180° peel strength of the first adhesive layer relative to the substrate at 23°C to 2.5 N / 25 mm or greater, the adhesion of the first adhesive layer to the substrate is further improved. The more preferred lower limit of the 180° peel strength of the first adhesive layer relative to the substrate at 23°C is 3.0 N / 25 mm, and even more preferably 3.5 N / 25 mm.

[0222] The preferred upper limit of the 180° peel strength of the first adhesive layer to the substrate at 23° C. is not particularly limited, but the practical upper limit is approximately 100 N / 25 mm.

[0223] The 180° peel strength of the first adhesive layer to the substrate at 23° C. can be measured by the following method.

[0224] Specifically, the adhesive tape was cut into a size of 25 mm wide by 100 mm long and then pressed against a 23 μm thick PET film using a 2 kg rubber roller, reciprocating once at a speed of 300 mm / min. The tape was then allowed to stand for 20 minutes in an environment of 23°C and 50% RH for curing to produce a test sample. The resulting test sample was subjected to a 180° peel test in accordance with JIS Z0237 using a tensile testing machine (Orientec, "Tensilon," etc.) at 23°C, 50% RH, and a peel speed of 300 mm / min. The first adhesive layer was peeled from the substrate to measure the 180° peel strength of the first adhesive layer against the substrate at 23°C.

[0225] The first adhesive layer preferably has a loss tangent (tan δ) measured at a frequency of 10 Hz in a dynamic viscoelasticity measurement (hereinafter sometimes referred to as "the loss tangent of the first adhesive layer measured at a frequency of 10 Hz") having a peak in a temperature range of -30°C to 15°C. By having the loss tangent (tan δ) of the first adhesive layer measured at a frequency of 10 Hz having a peak in a temperature range of -30°C or higher, the adhesion of the first adhesive layer to the substrate is further improved. Furthermore, by having the loss tangent (tan δ) of the first adhesive layer measured at a frequency of 10 Hz having a peak in a temperature range of 15°C or lower, the zippering phenomenon that occurs when the film protecting the adhesive layer of the adhesive tape is peeled off can be suppressed, allowing the resulting adhesive tape to be used without compromising adhesive strength.

[0226] The peak temperature at which the loss tangent of the first adhesive layer measured at a frequency of 10 Hz has a peak (hereinafter sometimes simply referred to as "the peak temperature of the loss tangent") is more preferably -25°C, and the upper limit is more preferably 13°C. The lower limit is still more preferably -20°C, and the upper limit is still more preferably 11°C.

[0227] The preferred lower limit of the shear storage modulus of the first adhesive layer at 25° C. measured at a frequency of 10 Hz in a dynamic viscoelasticity measurement is 1.0×10 4 Pa, the upper limit of which is preferably 5.0×10 5 Pa. By setting the shear storage modulus of the first adhesive layer at 25°C within the above range, the adhesive strength and holding performance of the obtained adhesive tape are further improved. In addition, the flexibility of the first adhesive layer is improved, the adhesive strength of the first adhesive layer to the fluororesin is improved, and the adhesion to the substrate is further improved. The more preferred lower limit of the shear storage modulus of the first adhesive layer at 25°C is 3.0×10 4 Pa, and a more preferred upper limit is 4.0×10 5Pa, and a further preferred lower limit is 5.0×10 4 Pa, and a more preferred upper limit is 3.5×10 5 Pa.

[0228] The peak temperature of the loss tangent of the first adhesive layer measured at a frequency of 10 Hz and the shear storage modulus of the first adhesive layer at 25° C. can be measured by dynamic viscoelasticity measurement.

[0229] Specifically, a measurement sample consisting solely of an adhesive layer is prepared by laminating the adhesive layer to a thickness of approximately 1 mm. The resulting measurement sample is then subjected to dynamic viscoelasticity measurement using a viscoelastic spectrometer (e.g., "DVA-200" manufactured by IT Instruments & Controls Co., Ltd.) under the following conditions: shear mode, a heating rate of 5°C / min, and a measurement frequency of 10 Hz. The shear storage modulus of the first adhesive layer can thereby be measured. Furthermore, the peak temperature of the loss tangent of the first adhesive layer can be determined from the dynamic viscoelastic spectrum obtained in this manner.

[0230] The peak temperature of the loss tangent (tan δ) of the first adhesive layer measured at a frequency of 10 Hz and the shear storage modulus of the first adhesive layer at 25° C. can be adjusted by the type and content ratio of the monomers constituting the (meth)acrylic acid-based copolymer, the weight-average molecular weight of the (meth)acrylic acid-based copolymer, the presence or absence of the tackifier resin (T2), the types and contents of the tackifier resin (T1) and the tackifier resin (T2), the gel fraction of the first adhesive layer described later, and the like.

[0231] The preferred lower limit of the gel fraction of the first adhesive layer is 15% by mass, and the preferred upper limit is 70% by mass. By setting the gel fraction of the first adhesive layer to 15% by mass or more, the overall strength of the first adhesive layer is improved, and the holding performance of the resulting adhesive tape is further improved. By setting the gel fraction of the first adhesive layer to 70% by mass or less, the shear storage modulus of the first adhesive layer at 25°C is moderately reduced, thereby further improving the flexibility of the first adhesive layer, improving the adhesion of the first adhesive layer to the fluororesin, and further improving the adhesion to the substrate. The more preferred lower limit of the gel fraction of the first adhesive layer is 20% by mass, the more preferred upper limit is 65% by mass, the further preferred lower limit is 25% by mass, and the further preferred upper limit is 60% by mass.

[0232] The gel fraction of the first pressure-sensitive adhesive layer can be measured by the following method or the like.

[0233] The adhesive tape was cut into a flat rectangular shape of 50 mm in width and 100 mm in length to prepare a test piece. The test piece was immersed in an organic solvent at 23°C for 24 hours, removed from the organic solvent, and dried at 110°C for 1 hour. It should be noted that as an organic solvent, for example, ethyl acetate can be used when the above-mentioned base polymer (P1) is a (meth)acrylic acid copolymer, and toluene can be used when the above-mentioned base polymer (P1) is a styrene elastomer. The mass of the test piece after drying was measured, and the gel fraction was calculated using the following formula (1). It should be noted that no release film for protecting the adhesive layer was laminated on the test piece.

[0234] Gel fraction (mass %) = 100 × (W2-W0) / (W1-W0) (1)

[0235] (W0: mass of the substrate, W1: mass of the test piece before immersion, W2: mass of the test piece after immersion and drying)

[0236] The gel fraction of the first adhesive layer can be adjusted to fall within the above range by, for example, adjusting the type and content ratio of monomers constituting the (meth)acrylic copolymer, the weight average molecular weight of the (meth)acrylic copolymer, the type and content of the curing agent, and the like.

[0237] The preferred lower limit of the thickness of the first adhesive layer is 20 μm, and the preferred upper limit is 500 μm. When the thickness of the first adhesive layer is within this range, the first adhesive layer can have sufficient adhesive strength. A more preferred lower limit of the thickness of the first adhesive layer is 25 μm, a more preferred upper limit is 300 μm, a further preferred upper limit is 100 μm, and an even more preferred upper limit is 80 μm.

[0238] The pressure-sensitive adhesive tape of the present invention may include the first pressure-sensitive adhesive layer and other layers other than the substrate as needed.

[0239] From the perspective of reworkability, the adhesive tape of the present invention preferably comprises an intermediate layer and a second adhesive layer in this order on the surface of the first adhesive layer opposite to the surface adjacent to the substrate. In other words, the adhesive tape of the present invention preferably comprises the substrate, the first adhesive layer, the intermediate layer, and the second adhesive layer in this order.

[0240] Generally, when an adhesive tape is bonded to an adherend made of metal or a highly polar resin (e.g., polyester or polyimide), the adhesive strength between the adhesive layer and the adherend tends to be higher than that between a substrate containing a fluororesin, such as the substrate described above, and the adhesive layer. Consequently, when attempting to peel the adhesive tape back, the tape may break between the substrate containing the fluororesin and the adhesive layer.

[0241] By including an intermediate layer in the adhesive tape of the present invention, the breakage between the substrate and the first adhesive layer can be further suppressed, thereby facilitating re-peeling of the adhesive tape and improving reworkability. Furthermore, by including the second adhesive layer on the outermost surface of the adhesive tape of the present invention, the adhesive tape's adherend selectivity is reduced, allowing it to be bonded to a variety of adherends.

[0242] The second adhesive layer may have a single-layer structure or a multi-layer structure, but is preferably a single-layer structure from the viewpoint of preventing interlayer damage between the adhesive layers.

[0243] The second pressure-sensitive adhesive layer preferably contains a base polymer (P2).

[0244] The base polymer (P2) preferably contains at least one selected from the group consisting of a (meth)acrylic copolymer and a styrene elastomer.

[0245] As the styrene-based elastomer in the base polymer (P2), the same styrene-based elastomer as that in the base polymer (P1) can be used.

[0246] As the (meth)acrylic acid-based copolymer in the base polymer (P2), the same (meth)acrylic acid-based copolymer as that in the base polymer (P1) can be used.

[0247] To further reduce the contamination of the adherend by the adhesive tape, the second adhesive layer preferably contains no organosilicon compound, or the organosilicon compound content in the second adhesive layer is 3.0% by mass or less. If the second adhesive layer contains an organosilicon compound, the more preferred upper limit of the content is 1.0% by mass. It is particularly preferred that the second adhesive layer contain no organosilicon compound.

[0248] From the viewpoint of further improving the adhesive strength, the second adhesive layer preferably further contains a tackifier resin (T3). Examples of the tackifier resin (T3) include the same tackifier resins as those described above for the tackifier resin (T2).

[0249] When the base polymer (P2) comprises the (meth)acrylic acid-based copolymer, the second adhesive layer preferably further contains a curing agent. By incorporating a curing agent into the second adhesive layer, the (meth)acrylic acid-based copolymer is chemically crosslinked, further improving the adhesive strength and holding performance of the resulting adhesive tape.

[0250] As the curing agent contained in the second adhesive layer, for example, the same curing agent as the curing agent contained in the first adhesive layer can be used.

[0251] The preferred upper limit of the probe tack of the second adhesive layer, measured at 23°C, 98 gf pressure, 100 mm / sec pressure speed, 10 seconds pressure duration, and 5 mm / sec separation speed (hereinafter sometimes referred to as the "probe tack of the second adhesive layer at 23°C"), is 20 N / 5 mmφ. By setting the probe tack of the second adhesive layer at 23°C to 20 N / 5 mmφ or less, tackiness of the second adhesive layer can be suppressed, thereby further improving the laminating workability of the adhesive tape of the present invention. The more preferred upper limit of the probe tack of the second adhesive layer at 23°C is 15 N / 5 mmφ, and even more preferably, 10 N / 5 mmφ.

[0252] Furthermore, the preferred lower limit of the probe tack at 23°C of the second adhesive layer is 0.01 N / 5 mmφ. By setting the probe tack at 23°C of the second adhesive layer to 0.01 N / 5 mmφ or greater, the second adhesive layer has moderate adhesive strength, facilitating adjustment of the application position of the adhesive tape of the present invention and improving lamination workability. A more preferred lower limit of the probe tack at 23°C of the second adhesive layer is 0.1 N / 5 mmφ, and an even more preferred lower limit of the probe tack at 23°C of the second adhesive layer is 1.0 N / 5 mmφ.

[0253] The probe tack of the second pressure-sensitive adhesive layer at 23° C. can be measured by a probe tack test in accordance with JIS Z3284.

[0254] Specifically, for example, the measurement can be performed as follows: a test piece is prepared by cutting the adhesive tape of the present invention into a size of 30 mm in width and 30 mm in length, and the second adhesive layer of the prepared test piece is subjected to a probe tack tester (manufactured by RHESCA, "TAC-2", etc.) at 23°C, a pressing force of 98 gf, a pressing speed of 100 mm / sec, a pressing time of 10 seconds, and a separation speed of 5 mm / sec.

[0255] Methods for adjusting the probe initial tack of the second adhesive layer at 23°C include: changing the composition, weight-average molecular weight, and molecular weight distribution of the base polymer (P2); changing the type and content ratio of the tackifying resin (T3); changing the type, content, and thickness of the second adhesive layer of the formulated microparticles and additives; changing the storage modulus and glass transition temperature; changing the crosslinking density; changing the surface roughness, etc.

[0256] The preferred upper limit of the 180° peel strength of the second adhesive layer against SUS at 23°C is 8.0 N / 25 mm. By setting the 180° peel strength of the second adhesive layer against SUS at 23°C to 8.0 N / 25 mm or less, the reworkability of the resulting adhesive tape is further improved. The more preferred upper limit of the 180° peel strength of the second adhesive layer against SUS at 23°C is 7.0 N / 25 mm, and the further preferred upper limit is 5.0 N / 25 mm.

[0257] Furthermore, the preferred lower limit of the 180° peel strength of the second adhesive layer against SUS at 23°C is 2.0 N / 25 mm. By setting the 180° peel strength of the second adhesive layer against SUS at 23°C to 2.0 N / 25 mm or greater, the adhesive strength of the resulting adhesive tape is further improved. The more preferred lower limit of the 180° peel strength of the second adhesive layer against SUS at 23°C is 2.5 N / 25 mm, and even more preferably 3.0 N / 25 mm.

[0258] The 180° peel strength of the second adhesive layer to SUS at 23° C. can be measured by the following method or the like.

[0259] Specifically, the adhesive tape was cut into a size of 25 mm wide by 100 mm long and then pressed against a SUS plate (SUS304 plate that had been cleaned with ethanol and dry-erased) using a 2 kg rubber roller, moving back and forth once at a speed of 300 mm / min. The tape was then allowed to stand for 20 minutes in an environment of 23°C and 50% RH for curing to produce a test sample. The resulting test sample was subjected to a 180° peel test in accordance with JIS Z0237 using a tensile testing machine (Orientec, Inc., "Tensilon," etc.) at 23°C, 50% RH, and a peel speed of 300 mm / min. The adhesive tape was peeled from the SUS plate to measure the 180° peel strength of the second adhesive layer against the SUS at 23°C.

[0260] The preferred lower limit of the thickness of the second adhesive layer is 20 μm, and the preferred upper limit is 500 μm. By setting the thickness of the second adhesive layer within this range, the second adhesive layer can have sufficient adhesive strength. A more preferred lower limit of the thickness of the second adhesive layer is 25 μm, a more preferred upper limit is 300 μm, a further preferred upper limit is 100 μm, and an even more preferred upper limit is 80 μm.

[0261] From the perspective of achieving high adhesion with the first and second adhesive layers, the intermediate layer preferably comprises at least one selected from the group consisting of polyester resins, polyimide resins, polyolefin resins, polyurethane resins, glass fibers, carbon fibers, and metals. From the perspective of achieving even higher adhesion, it is more preferred that the intermediate layer comprises at least one selected from the group consisting of polyester resins and polyolefin resins.

[0262] Examples of the polyester resin include polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT), polyethylene furandicarboxylate (PEF), polylactic acid (PLA), and polybutylene succinate (PBS).

[0263] Examples of the polyimide resin include Kapton (manufactured by DuPont) and Upilex (manufactured by UBE).

[0264] Examples of the polyolefin resin include polyethylene (PE), polypropylene (PP), and ethylene-vinyl acetate copolymer (EVA).

[0265] The polyurethane resin is a resin composition composed of a polyisocyanate and a polyol. Examples of the polyisocyanate include 4,4′-diphenylmethane diisocyanate (MDI) and examples of the polyol include polypropylene glycol (PPG).

[0266] Examples of the metal include SUS, copper, and aluminum.

[0267] Examples of the shape of the intermediate layer include film, nonwoven fabric, and textile. Of these, from the perspective of high adhesion between the intermediate layer and the first and second adhesive layers, the intermediate layer is preferably in at least one form selected from nonwoven fabric and textile.

[0268] Examples of the nonwoven fabric substrate include G2260-1S (manufactured by TORAY INTERNATIONAL CO., LTD.).

[0269] Examples of the textile substrate include glass cloth and carbon cloth. Specific examples of the glass cloth include KS2770 (manufactured by Nitto Bosho Co., Ltd.), and specific examples of the carbon cloth include C-540 (manufactured by Hagiwara Industries, Ltd.).

[0270] The intermediate layer may have a foamed structure. By making the intermediate layer have a foamed structure, the flexibility of the intermediate layer is further improved, and the holding performance and reworkability of the obtained adhesive tape are further improved.

[0271] Examples of the intermediate layer having a foamed structure include foams of the polyolefin resin and foams of the polyurethane resin.

[0272] The preferred lower limit of the thickness of the intermediate layer is 4 μm, and the preferred upper limit is 500 μm. By adjusting the thickness of the intermediate layer within this range, the reworkability of the resulting adhesive tape is further improved. The more preferred lower limit of the thickness of the intermediate layer is 12 μm, the more preferred upper limit is 300 μm, the further preferred lower limit is 23 μm, and the further preferred upper limit is 200 μm.

[0273] From the viewpoint of laminating workability, the adhesive tape of the present invention preferably includes the substrate, the first adhesive layer, and the hot-melt adhesive layer in this order.

[0274] In this specification, the "hot-melt adhesive layer" refers to an adhesive layer that is melted by heating and adheres to an adherend.

[0275] Conventionally, adhesives used for attaching fluororesins have had excessively strong adhesion to the adherend at room temperature, which can lead to poor workability due to stickiness and difficulty adjusting the position of the fluororesin attached to the adherend. Therefore, adhesives with excellent workability, low stickiness, and ease of adjustment of the fluororesin attachment position on the adherend are preferred.

[0276] By having a hot-melt adhesive layer on the outermost surface of the pressure-sensitive adhesive tape of the present invention, tackiness of the pressure-sensitive adhesive tape at room temperature can be further suppressed, resulting in excellent laminating workability.

[0277] The hot melt adhesive layer may have a single-layer structure or a multi-layer structure, but is preferably a single-layer structure from the viewpoint of preventing interlayer damage between the adhesive layers.

[0278] The preferred lower limit of the 180° peel strength of the hot-melt adhesive layer against SUS at 23°C (hereinafter sometimes referred to as the "180° peel strength of the hot-melt adhesive layer against SUS at 23°C after heating"), when pressure-bonded at 0.1 MPa for 10 minutes in a 150°C environment, is 5.0 N / 25 mm. By achieving a 180° peel strength of 5.0 N / 25 mm or greater against SUS at 23°C after heating, the hot-melt adhesive layer exhibits excellent adhesive strength upon heating. Therefore, the adhesive tape of the present invention achieves both excellent lamination workability and excellent adhesive strength. The preferred lower limit of the 180° peel strength of the hot-melt adhesive layer against SUS at 23°C after heating is 7.0 N / 25 mm, and a more preferred lower limit is 10.0 N / 25 mm.

[0279] The upper limit of the 180° peel strength of the hot melt adhesive layer against SUS at 23° C. after heating is not particularly limited, but the practical upper limit is 500 N / 25 mm.

[0280] The 180° peel strength of the hot melt adhesive layer to SUS at 23° C. after heating can be measured by the following method or the like.

[0281] Specifically, the adhesive tape was cut into a size of 25 mm wide by 100 mm long. A 23 μm-thick PET film (e.g., "FE2002" manufactured by Futamura Chemical Co., Ltd.) was used as a backing for the first adhesive layer. The hot-melt adhesive layer was then pressure-bonded to a SUS plate (SUS304 plate cleaned with ethanol and dry-erased) under 0.1 MPa pressure at 150°C for 10 minutes. The plate was then air-cooled to produce a test sample. The resulting test sample was subjected to a 180° peel test using a tensile testing machine (e.g., "Tensilon" manufactured by ORIENTEC Co., Ltd.) at 23°C, 50% RH, and a peel speed of 300 mm / min in accordance with JIS Z0237. The adhesive tape was peeled from the SUS plate to measure the 180° peel strength of the hot-melt adhesive layer against the SUS at 23°C.

[0282] Examples of methods for adjusting the 180° peel strength of the hot melt adhesive layer to SUS at 23° C. after heating include changing the composition of the base polymer (P3) described below and changing the thickness of the hot melt adhesive layer.

[0283] The preferred upper limit of the 180° peel strength of the hot-melt adhesive layer against SUS at 23°C is 15 N / 25 mm. By setting the 180° peel strength of the hot-melt adhesive layer against SUS at 23°C to 15 N / 25 mm or less, the attaching workability of the resulting adhesive tape is further improved. The more preferred upper limit of the 180° peel strength of the hot-melt adhesive layer against SUS at 23°C is 12 N / 25 mm, and even more preferably 10 N / 25 mm.

[0284] Specifically, the adhesive tape was cut into a size of 25 mm wide by 100 mm long and then pressure-bonded to a SUS plate (SUS304 plate that had been cleaned with ethanol and dry-erased) using a 2 kg rubber roller, moving back and forth once at a speed of 300 mm / min. The tape was then allowed to stand for 20 minutes in an environment of 23°C and 50% RH for curing to produce a test sample. The resulting test sample was subjected to a 180° peel test in accordance with JIS Z0237 using a tensile testing machine (Orientec, Inc., "Tensilon," etc.) at 23°C, 50% RH, and a peel speed of 300 mm / min. The adhesive tape was peeled from the SUS plate to measure the 180° peel strength of the hot-melt adhesive layer against the SUS at 23°C.

[0285] Examples of methods for adjusting the 180° peel strength of the hot melt adhesive layer to SUS at 23° C. include changing the composition of the base polymer (P3) and changing the thickness of the hot melt adhesive layer.

[0286] The hot-melt adhesive layer preferably contains a base polymer (P3).

[0287] The base polymer (P3) preferably comprises at least one selected from the group consisting of (meth)acrylic copolymers, styrene elastomers, ethylene-vinyl acetate copolymers, chloroprene rubber, nitrile rubber, polyurethane resins, polyamide resins, polyolefin resins, polyester resins, and epoxy resins. Among these, (meth)acrylic copolymers, styrene elastomers, chloroprene rubber, nitrile rubber, polyurethane resins, polyamide resins, polyolefin resins, and polyester resins are preferred from the viewpoints of viscosity control and heat resistance.

[0288] The (meth)acrylic copolymer and styrene elastomer in the base polymer (P3) may be the same as those in the base polymer (P1) and the base polymer (P2).

[0289] Specific examples of the (meth)acrylic acid-based copolymer in the base polymer (P3) include SK Dyne 1717DT (manufactured by Soken Chemical Co., Ltd.).

[0290] Examples of the ethylene-vinyl acetate copolymer include HM200 (manufactured by CEMEDINE).

[0291] Examples of the chloroprene rubber include 575F (manufactured by CEMEDINE Co., Ltd.) and G17 (manufactured by Konishi Co., Ltd.).

[0292] Examples of the nitrile rubber include 501F (manufactured by CEMEDINE).

[0293] As said polyurethane resin, SHM107-PUR (made by Sheedom Co., Ltd.) etc. are mentioned, for example.

[0294] Examples of the polyamide resin include SHM301-PAD (manufactured by Sheedom Co., Ltd.) and the like.

[0295] As said polyolefin resin, PPET1401SG (made by Toagosei Co., Ltd.) etc. are mentioned, for example.

[0296] As said epoxy resin, 1500 (made by CEMEDINE) etc. are mentioned, for example.

[0297] Examples of the polyester resin include PH-413 (manufactured by Nihon Matai Co., Ltd.).

[0298] To further reduce the contamination of the adhesive tape on adherends, the hot melt adhesive layer preferably contains no organosilicon compounds, or the organosilicon compound content in the hot melt adhesive layer is preferably 3.0% by mass or less. If the hot melt adhesive layer contains an organosilicon compound, the more preferred upper limit of the content is 1.0% by mass. It is particularly preferred that the hot melt adhesive layer contain no organosilicon compounds.

[0299] From the perspective of further improving adhesive strength, the hot melt adhesive layer preferably further contains a tackifier resin (T4). Examples of the tackifier resin (T4) include the same tackifier resins as those described above for the tackifier resin (T2) and the tackifier resin (T3).

[0300] When the base polymer (P3) comprises the (meth)acrylic acid copolymer, the hot-melt adhesive layer preferably further contains a curing agent. By incorporating a curing agent into the hot-melt adhesive layer, the (meth)acrylic acid copolymer is cross-linked by chemical cross-linking, further enhancing the adhesive strength of the resulting adhesive tape.

[0301] As the curing agent contained in the hot-melt adhesive layer, for example, the same curing agent as that contained in the first adhesive layer and the second adhesive layer can be used.

[0302] The hot melt adhesive layer may contain conventionally known fine particles and additives such as inorganic fine particles, conductive fine particles, an antioxidant, a foaming agent, an organic filler, and an inorganic filler, as needed.

[0303] The preferred upper limit of the probe tack of the hot melt adhesive layer, measured at 23°C, 98 gf pressure, 100 mm / sec pressure speed, 10 seconds pressure duration, and 5 mm / sec separation speed (hereinafter sometimes referred to as "the probe tack of the hot melt adhesive layer at 23°C"), is 20 N / 5 mmφ. By setting the probe tack of the hot melt adhesive layer at 23°C to 20 N / 5 mmφ or less, the tackiness of the hot melt adhesive layer can be suppressed, thereby further improving the workability of applying the adhesive tape of the present invention. The more preferred upper limit of the probe tack of the hot melt adhesive layer at 23°C is 15 N / 5 mmφ, and even more preferably, 10 N / 5 mmφ.

[0304] The preferred lower limit of the probe tack at 23°C of the hot-melt adhesive layer is 0.01 N / 5 mmφ. By setting the probe tack at 23°C of 0.01 N / 5 mmφ or greater, the hot-melt adhesive layer has moderate adhesive strength, facilitating adjustment of the application position of the adhesive tape of the present invention and improving application workability. A more preferred lower limit of the probe tack at 23°C of the hot-melt adhesive layer is 0.1 N / 5 mmφ, and an even more preferred lower limit of the probe tack at 23°C of the hot-melt adhesive layer is 1.0 N / 5 mmφ.

[0305] The probe tack of the hot melt adhesive layer at 23° C. can be measured by the same method as the probe tack of the second adhesive layer at 23° C.

[0306] Methods for adjusting the probe tack at 23°C of the hot-melt adhesive layer include: changing the composition, weight-average molecular weight, and molecular weight distribution of the base polymer (P3); changing the type and content of the tackifying resin (T4); changing the type and content of the microparticles and additives, and the thickness of the hot-melt adhesive layer; changing the storage modulus and glass transition temperature; and changing the crosslink density. Examples of methods include changing the surface roughness.

[0307] The preferred lower limit of the thickness of the hot melt adhesive layer is 20 μm, and the preferred upper limit is 500 μm. By setting the thickness of the hot melt adhesive layer within this range, the hot melt adhesive layer can have sufficient adhesive strength. The more preferred lower limit of the thickness of the hot melt adhesive layer is 25 μm, the more preferred upper limit is 300 μm, the more preferred upper limit is 100 μm, and the most preferred upper limit is 80 μm.

[0308] When the adhesive tape of the present invention comprises the substrate, the first adhesive layer, and the hot-melt adhesive layer in this order, an intermediate layer may be provided between the first adhesive layer and the hot-melt adhesive layer. The intermediate layer improves the reworkability of the resulting adhesive tape.

[0309] Examples of the intermediate layer include the same intermediate layer as that in the pressure-sensitive adhesive tape comprising the substrate, the first pressure-sensitive adhesive layer, the intermediate layer, and the second pressure-sensitive adhesive layer in this order.

[0310] The method for producing the pressure-sensitive adhesive tape of the present invention is not particularly limited. For example, in the case of a pressure-sensitive adhesive tape comprising a substrate and a first pressure-sensitive adhesive layer adjacent to one surface of the substrate, the following method can be used.

[0311] First, a solvent is added to a (meth)acrylic copolymer, a tackifying resin (T1), a tackifying resin (T2), a curing agent, etc. to prepare an adhesive solution (a). This adhesive solution is applied to one surface of a substrate, and the solvent in the solution is completely dried and removed to form a first adhesive layer.

[0312] Next, a release film is superposed on the formed adhesive layer with its release-treated surface facing the adhesive layer, thereby obtaining an adhesive tape having a substrate and a first adhesive layer adjacent to one surface of the substrate.

[0313] The process of applying the adhesive solution to one surface of the substrate can be completed once, or can be performed multiple times and applied in a manner overlapping with the adhesive solution already applied. By adjusting the number of times the application process is performed, the thickness of the first adhesive layer can be easily adjusted.

[0314] Furthermore, the thickness of the second adhesive layer and the hot-melt adhesive layer can also be easily adjusted by adjusting the number of times the adhesive application step is performed in the adhesive tape production process.

[0315] The adhesive tape of the present invention may be in a roll form. By making the adhesive tape of the present invention in a roll form, the long adhesive tape can be shipped in a roll form, and as a result, the adhesive tape can be appropriately unwound from the roll and cut into a suitable shape for use.

[0316] When the adhesive tape of the present invention is in roll form, for example, a method of manufacturing the adhesive tape may include a method in which the adhesive tape is wound around a core after undergoing an adhesive application step, a cutting step using a slitter, or a rewinding step.

[0317] The adhesive tape of the present invention has no particular limitations on its uses. Since it comprises a substrate containing a film containing a fluororesin, it is suitable for bonding fluororesins to various components for various purposes. More specifically, these various purposes include promoting sliding on friction surfaces, preventing sliding of sliding portions, providing insulation, and protecting adherends from high temperatures, chemical solutions, and the like. Among these, it is particularly suitable for protecting adherends, and particularly for protecting adherends from chemical solutions. Adhesives to be protected from chemical solutions are not particularly limited, but examples include tanks, receiving trays, and walls.

[0318] Specifically, it can be suitably used as a coating material for chemical tanks for semiconductors or chemical industries, for piping used to transport chemical solutions, for coating materials for electronic equipment components, and for building materials. The adhesive tape of the present invention is preferably used for the inner lining of a tank body (a surface treatment covering the inner surface of a tank body) in chemical tanks for semiconductors or chemical industries. Furthermore, when the adhesive tape of the present invention has a hot-melt adhesive layer on its outermost surface, the resulting adhesive tape exhibits excellent lamination workability and is more preferably used for the inner lining of a tank body in chemical tanks for semiconductors or chemical industries. A chemical tank formed by affixing the adhesive tape of the present invention to the inner surface of a tank body is also an aspect of the present invention.

[0319] Another aspect of the present invention is a method for manufacturing a chemical tank for semiconductors or the chemical industry, including a step of affixing the adhesive tape of the present invention to the inner surface of the tank body. Because the adhesive tape comprises a base material comprising a resin film containing a fluororesin, the method for manufacturing a chemical tank of the present invention, including the step of affixing the adhesive tape to the inner surface of the tank body, eliminates the need for performing adhesion-facilitating treatment on the fluororesin when joining the fluororesin to the tank body, thereby facilitating the joining of the fluororesin to the tank body.

[0320] In addition, when the above-mentioned adhesive tape has a hot-melt adhesive layer on the outermost surface, the bonding workability of the above-mentioned adhesive tape becomes excellent. Therefore, the manufacturing method of the liquid medicine tank of the present invention includes a step of sticking the above-mentioned adhesive tape to the inner surface of the tank body in the liquid medicine tank, thereby making it easy to adjust the position where the fluororesin is joined to the tank body in the liquid medicine tank.

[0321] Effects of the Invention

[0322] The present invention provides an adhesive tape that exhibits excellent holding performance, minimizes adherend contamination, and facilitates fluororesin bonding. Furthermore, the present invention provides a chemical tank to which the adhesive tape is affixed. Furthermore, the present invention provides a method for manufacturing a chemical tank using the adhesive tape. BRIEF DESCRIPTION OF THE DRAWINGS

[0323] Figure 1 It is a schematic diagram showing the method of the retention test. DETAILED DESCRIPTION

[0324] Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

[0325] (Preparation of Acrylic Copolymer)

[0326] (Synthesis example 1)

[0327] 100 parts by mass of ethyl acetate was added to a reactor equipped with a thermometer, a stirrer, and a condenser tube. After nitrogen substitution, the reactor was heated and refluxed. After the ethyl acetate was boiled, 0.08 parts by mass of azobisisobutyronitrile was added as a polymerization initiator 30 minutes later. The monomer mixture of the structural unit monomers shown in Table 1 was evenly and slowly added dropwise over 1 hour and 30 minutes and allowed to react. 30 minutes after the addition was completed, 0.1 parts by mass of azobisisobutyronitrile was added, and the polymerization reaction was further carried out for 5 hours. Ethyl acetate was added to the reactor and cooled while diluting to obtain a solution of an acrylic copolymer having a solid content of 25% by mass.

[0328] The resulting acrylic copolymer solution was filtered through a filter (material: polytetrafluoroethylene, pore size: 0.2 μm). The resulting filtrate was fed to a gel permeation chromatograph (Waters, 2690 Separations Module) for GPC measurement at a sample flow rate of 1 mL / min and a column temperature of 40°C. The polystyrene-equivalent molecular weight of the acrylic copolymer was measured, and the weight-average molecular weight (Mw) and molecular weight distribution (Mw / Mn) were determined. A GPC KF-806L (Showa Denko K.K.) column was used, and a differential refractometer was used as the detector. The results are shown in Table 1.

[0329] (Synthesis Examples 2 to 10)

[0330] An acrylic copolymer was obtained in the same manner as in Synthesis Example 1 except that the monomer mixture was changed as shown in Table 1. The results are shown in Table 1.

[0331] In addition, the structural unit monomers shown in Table 1 represent the following monomers.

[0332] BA: n-butyl acrylate

[0333] 2EHA: 2-ethylhexyl acrylate

[0334] LA: Lauryl acrylate

[0335] nHA: n-heptyl acrylate

[0336] HEA: 2-Hydroxyethyl Acrylate

[0337] AAc: acrylic acid

[0338] [Table 1]

[0339]

[0340] (Preparation of Tackifying Resin (T1))

[0341] (Synthesis Example A)

[0342] A reactor equipped with a thermometer, a stirrer, and a condenser was charged with 50 parts by mass of toluene. After nitrogen substitution, the reactor was heated and refluxed. After 30 minutes, 2 parts by mass of aluminum chloride (AlCl₃) was added while the toluene was maintained at 75°C. A solution of 50 parts by mass of catechol (catechol) (n=2) and α-pinene (the molar ratios are shown in Table 2) dissolved in 50 parts by mass of toluene was slowly added dropwise over 1 hour and 30 minutes to allow the reaction to proceed. After a 4-hour polymerization reaction, 0.1 parts by mass of pyridine was added to the reactor while cooling to neutralize the hydrochloric acid generated by the aluminum chloride (AlCl₃). The resulting precipitate was filtered, and the resulting filtrate was separated. The toluene was then evaporated to obtain a solid tackifier resin (T1).

[0343] The obtained tackifying resin (T1) was 1 H-NMR measurement confirmed that the tackifier resin (T1) was a copolymer having a structural unit (A) derived from catechol (catechol) and a structural unit (B) derived from α-pinene (a copolymer having the structural unit (A) in the main chain skeleton or at a terminal of the main chain skeleton).

[0344] A solution of the obtained tackifier resin (T1) dissolved in tetrahydrofuran was filtered through a filter (material: polytetrafluoroethylene, pore size: 0.2 μm). The resulting filtrate was fed to a gel permeation chromatograph (2690 Separations Module, manufactured by Waters) for GPC measurement at a sample flow rate of 1 mL / min and a column temperature of 40°C. The polystyrene-equivalent molecular weight of the tackifier resin (T1) was measured to determine the weight-average molecular weight (Mw). A GPC KF-802.5L (manufactured by Showa Denko K.K.) column was used, and a differential refractometer was used as the detector. The results are shown in Table 2.

[0345] (Measurement of the Biomass-Derived Carbon Content of Tackifying Resin (T1))

[0346] The biomass-derived carbon content of the obtained tackifying resin (T1) was measured in accordance with ASTM D6866-22. The results are shown in Table 2.

[0347] (Synthesis Examples B to C and E)

[0348] In the above “(Preparation of Tackifier Resin (T1))”, the tackifier resin (T1) was synthesized and measured in the same manner as in Synthesis Example A except that the monomers were changed as shown in Table 2. The results are shown in Table 2.

[0349] (Synthesis Example D)

[0350] (Preparation of Tackifying Resin (T1))

[0351] A reactor equipped with a thermometer, a stirrer, and a condenser was charged with 50 parts by mass of toluene. After nitrogen substitution, the reactor was heated and refluxed. After 30 minutes, 2 parts by mass of aluminum chloride (AlCl₃) was added while the toluene temperature was maintained at 75°C. A solution of 70 parts by mass of 4-vinylbenzoic acid (m=1) and α-pinene (the molar ratios are shown in Table 2) dissolved in 50 parts by mass of toluene was slowly added dropwise over 1 hour and 30 minutes to allow the reaction to proceed. After a 4-hour polymerization reaction, 0.1 parts by mass of pyridine was added to the reactor while cooling to neutralize the hydrochloric acid generated by the aluminum chloride (AlCl₃). The resulting precipitate was filtered, and the resulting filtrate was separated. The toluene was then evaporated to obtain a solid tackifier resin (T1).

[0352] The obtained tackifying resin (T1) was l H-NMR measurement confirmed that the tackifier resin (T1) was a copolymer having a structural unit (A) derived from 4-vinylbenzoic acid and a structural unit (B) derived from α-pinene (a copolymer having the structural unit (A) in a side chain).

[0353] A solution of the obtained tackifier resin (T1) dissolved in tetrahydrofuran was filtered through a filter (material: polytetrafluoroethylene, pore size: 0.2 μm). The resulting filtrate was fed to a gel permeation chromatograph (2690 Separations Module, manufactured by Waters) for GPC measurement at a sample flow rate of 1 mL / min and a column temperature of 40°C. The polystyrene-equivalent molecular weight of the tackifier resin (T1) was measured to determine the weight-average molecular weight (Mw). A GPC KF-802.5L (manufactured by Showa Denko K.K.) column was used, and a differential refractometer was used as the detector. The results are shown in Table 2.

[0354] (Measurement of the Biomass-Derived Carbon Content of Tackifying Resin (T1))

[0355] The biomass-derived carbon content of the obtained tackifying resin (T1) was measured in accordance with ASTM D6866-22. The results are shown in Table 2.

[0356] [Table 2]

[0357]

[0358] (Example 1)

[0359] (1) Production of adhesive tape

[0360] To 100 parts by mass of the solid content of the acrylic copolymer (Synthesis Example 1), 20 parts by mass of a tackifier resin (T2) ("Pine Crystal KE-359," manufactured by Arakawa Chemical Industries, Ltd.) was added. Furthermore, 30 parts by mass of ethyl acetate (manufactured by Fuji Chemicals Co., Ltd.) and 1.0 part by mass of an isocyanate curing agent ("Coronate L45," manufactured by Tosoh Corporation) were added, and the mixture was thoroughly stirred to obtain an adhesive solution.

[0361] The resulting adhesive solution was applied to a 50 μm-thick PTFE sheet ("Yodofluon," manufactured by Yodogawa Hu-Tech Co., Ltd.) and dried at 100°C for 5 minutes to form a 50 μm-thick first adhesive layer. A 150 μm-thick release PET film was also prepared and overlaid on the release-treated first adhesive layer. The film was then heated at 40°C for 48 hours for curing. This produced an adhesive tape comprising a substrate and a first adhesive layer on one side of the substrate, the surface of the first adhesive layer being covered with the release PET film.

[0362] (2) Determination of the 180° peel strength of the first adhesive layer to the substrate at 23°C

[0363] The resulting adhesive tape was cut into pieces measuring 25 mm wide by 100 mm long. After peeling off the release PET film, the cut adhesive tape was pressure-bonded to a 50 μm thick PET film using a 2 kg rubber roller, moving it back and forth once at a speed of 300 mm / min. The tape was then allowed to stand for 20 minutes in an environment of 23°C and 50% RH for curing, thereby producing a test sample.

[0364] The resulting test samples were subjected to a 180° peel test in accordance with JIS Z0237 using a tensile testing machine (Orientec, "Tensilon") at 23°C, 50% RH, and a peel speed of 300 mm / min. The first adhesive layer was peeled from the substrate, and the 180° peel force (N / 25 mm) of the first adhesive layer against the substrate at 23°C was measured. The results are shown in Table 3.

[0365] (3) Measurement of the peak temperature of the loss tangent (tan δ) of the first adhesive layer measured at a frequency of 10 Hz

[0366] In the above "(1) Preparation of Adhesive Tape," the prepared adhesive solution was applied to a 50 μm thick release PET film and dried at 100°C for 5 minutes to form a 50 μm thick first adhesive layer. This first adhesive layer was then laminated to a thickness of 1 mm to produce a measurement sample consisting solely of the adhesive layer. The obtained measurement sample was subjected to dynamic viscoelasticity measurement from -100°C to 200°C using a viscoelastic spectrometer (DVA-200, manufactured by IT Instruments & Controls Co., Ltd.) in shear mode, at a heating rate of 5°C / min and a measurement frequency of 10 Hz. The peak temperature (°C) of the loss tangent (tan δ) was determined from the obtained dynamic viscoelasticity spectrum. The results are shown in Table 3.

[0367] (4) Measurement of shear storage modulus of the first adhesive layer at 25°C

[0368] In the above-mentioned "(1) Preparation of Adhesive Tape", the prepared adhesive solution was applied to a 50 μm thick release PET film and dried at 100°C for 5 minutes to form a first adhesive layer having a thickness of 50 μm. The formed first adhesive layer was laminated to a thickness of 1 mm to prepare a measurement sample consisting only of the first adhesive layer. The obtained measurement sample was subjected to dynamic viscoelasticity spectrum measurement from -100°C to 200°C using a viscoelastic spectrometer (manufactured by IT Measurement and Control Co., Ltd., "DVA-200") under the conditions of shear mode, a heating rate of 5°C / min, and a measurement frequency of 10 Hz. The shear storage modulus (×10 4 The results are shown in Table 3.

[0369] (5) Measurement of the gel fraction of the first adhesive layer

[0370] Test pieces were prepared by cutting the adhesive tape into a flat rectangular shape measuring 50 mm wide by 100 mm long. The test pieces were immersed in ethyl acetate at 23°C for 24 hours, removed from the ethyl acetate, and dried at 110°C for 1 hour. The mass of the dried test pieces was measured, and the gel fraction (mass %) was calculated using the following formula (1). Note that no release film was laminated on the test pieces to protect the first adhesive layer. The results are shown in Table 3.

[0371] Gel fraction (mass %) = 100 × (W2-W0) / (W1-W0) (1)

[0372] (W0: mass of the substrate, W1: mass of the test piece before immersion, W2: mass of the test piece after immersion and drying)

[0373] (Examples 2 to 46, Comparative Examples 1 to 4)

[0374] In the above "(1) Preparation of Adhesive Tape", adhesive tapes were prepared and measured in the same manner as in Example 1, except that the composition of the first adhesive layer and the type and thickness of the substrate were changed as shown in Tables 3 to 5 and 9. The results are shown in Tables 3 to 5 and 9.

[0375] (Example 47)

[0376] (1) Production of adhesive tape

[0377] To 100 parts by mass of the solid content of the acrylic copolymer (Synthesis Example 1), 20 parts by mass of a tackifier resin (T2) ("Pine Crystal KE-359," manufactured by Arakawa Chemical Industries, Ltd.) was added. Furthermore, 30 parts by mass of ethyl acetate (manufactured by Fuji Chemicals Co., Ltd.) and 1.0 part by mass of an isocyanate curing agent ("Coronate L45," manufactured by Tosoh Corporation) were added, and the mixture was thoroughly stirred to obtain an adhesive solution (a).

[0378] The obtained adhesive solution (a) was applied to a 50 μm thick PTFE sheet (manufactured by Yodogawa Hu-Tech Co., Ltd., "Yodofluon") and dried at 100°C for 5 minutes to produce a laminated film (a) having a first adhesive layer of 50 μm thickness. The laminated film was then overlaid with a 50 μm thick PET film (manufactured by Futamura Chemical Co., Ltd., FE2002) so that the first adhesive layer faced each other, thereby obtaining a laminated body.

[0379] Similarly, 10 parts by mass of a tackifier resin (T3) (YS Polyster G150, manufactured by Yasuhara Chemical Co., Ltd.) was added to 100 parts by mass of the solid content of the acrylic copolymer (Synthesis Example 1). Furthermore, 30 parts by mass of ethyl acetate (manufactured by Fuji Chemicals Co., Ltd.) and 1.0 part by mass of an isocyanate curing agent (Coronate L45, manufactured by Tosoh Corporation) were added, and the mixture was thoroughly stirred to obtain an adhesive solution (b).

[0380] The adhesive solution (b) was applied to the release-treated surface of a 50 μm thick release PET film and dried at 100°C for 5 minutes to produce a laminated film (b) having a 20 μm thick second adhesive layer. Furthermore, the laminated film (b) was overlaid with the second adhesive layer facing the PET film side of the laminate, and the film was cured at 40°C for 48 hours to produce an adhesive tape comprising, in this order, a substrate, a first adhesive layer, an intermediate layer, and a second adhesive layer.

[0381] (2) Determination of the 180° peel strength of the first adhesive layer to the substrate at 23°C

[0382] The same procedures as in Example 1 were followed, except that the laminate described in "(1) Preparation of Adhesive Tape" was used as the test sample. The 180° peel strength (N / 25 mm) of the first adhesive layer against the substrate at 23°C was measured. The results are shown in Table 6.

[0383] (3) Measurement of the peak temperature of the loss tangent (tan δ) of the first adhesive layer measured at a frequency of 10 Hz

[0384] The peak temperature (° C.) of the loss tangent (tan δ) of the first pressure-sensitive adhesive layer measured at a frequency of 10 Hz was measured in the same manner as in Example 1. The results are shown in Table 6.

[0385] (4) Measurement of shear storage modulus of the first adhesive layer at 25°C

[0386] The same operation as in Example 1 was carried out to measure the shear storage modulus (×10 4 Pa). The results are shown in Table 6.

[0387] (5) Measurement of the gel fraction of the first adhesive layer

[0388] The gel fraction (mass %) of the first adhesive layer was measured in the same manner as in Example 1, except that the laminated film (a) in "(1) Preparation of Adhesive Tape" was cut to prepare a test piece instead of the adhesive tape. The results are shown in Table 6.

[0389] (6) Determination of 180° peel strength of the second adhesive layer against SUS at 23°C

[0390] The resulting adhesive tape was cut into pieces measuring 25 mm wide by 100 mm long. Using a 2 kg rubber roller, the tape was pressure-bonded to a SUS plate (SUS304 plate that had been cleaned with ethanol and dry-erased) by reciprocating once at a speed of 300 mm / min. The tape was then allowed to stand for 20 minutes in an environment of 23°C and 50% RH for curing, thereby producing a test sample.

[0391] The resulting test samples were subjected to a 180° peel test in accordance with JIS Z0237 using a tensile testing machine (Tensilon, manufactured by ORIENTEC) at 23°C, 50% RH, and a peel rate of 300 mm / min. The adhesive tape was peeled from a SUS plate. The 180° peel strength (N / 25 mm) of the second adhesive layer against the SUS at 23°C was measured. The results are shown in Table 6.

[0392] (7) Measurement of probe tack of the second adhesive layer at 23°C

[0393] The resulting adhesive tape was cut into test pieces measuring 30 mm wide by 30 mm long. The second adhesive layer of each test piece was subjected to a probe tack test using a probe tack tester ("TAC-2," manufactured by RHESCA) at 23°C, a pressure of 98 gf, a pressing speed of 100 mm / sec, a pressing time of 10 seconds, and a separation speed of 5 mm / sec. The probe tack of the second adhesive layer at 23°C was measured. The results are shown in Table 6.

[0394] (Examples 48 to 80, Comparative Examples 5 to 7)

[0395] In the above “(1) Preparation of Adhesive Tape”, an adhesive tape was prepared and measured in the same manner as in Example 47 except that the composition and thickness of each layer were changed as shown in Tables 6 to 7 and 9. The results are shown in Tables 6 to 7 and 9.

[0396] (Example 81)

[0397] In the above "(1) Preparation of Adhesive Tape", an adhesive tape was prepared and measured in the same manner as in Example 45, except that the intermediate layer was changed to closed-cell PE foam (WL02, manufactured by Sekisui Chemical Co., Ltd.). The results are shown in Table 7.

[0398] (Example 82)

[0399] In the above "(1) Preparation of Adhesive Tape," laminated film (a) and laminated film (b) were stacked with the first adhesive layer and the second adhesive layer facing each other, and cured at 40°C for 48 hours to produce an adhesive tape. In the above "(2) Measurement of 180° Peel Strength of the First Adhesive Layer from a Substrate at 23°C," the same procedures as in Example 1 were followed, except that laminated film (a) was used instead of the adhesive tape. Adhesive tapes were produced and measured in the same manner as in Example 47. The results are shown in Table 7.

[0400] (Example 83)

[0401] (1) Production of adhesive tape

[0402] To 100 parts by mass of the solid content of the acrylic copolymer (Synthesis Example 2), 10 parts by mass of a tackifier resin (T1) (Synthesis Example B) was added. Furthermore, 30 parts by mass of ethyl acetate (manufactured by Fuji Chemicals Co., Ltd.) and 0.5 parts by mass of an isocyanate curing agent ("Desmodur L-75" manufactured by Covestro Corporation) were added, and the mixture was thoroughly stirred to obtain an adhesive solution (a).

[0403] The obtained adhesive solution (a) was applied to a 50 μm thick PTFE sheet (manufactured by Yodogawa Hu-Tech Co., Ltd., “Yodofluon”) and dried at 100°C for 5 minutes to produce a laminated film (a) having a first adhesive layer with a thickness of 50 μm. The laminated film was then overlaid with a 50 μm thick PET film (manufactured by Futamura Chemical Co., Ltd., “FE2002”) so that the first adhesive layer faced each other, thereby obtaining a laminated body.

[0404] Similarly, 10 parts by mass of a tackifier resin (T4) (YS Polyster G150, manufactured by Yasuhara Chemical Co., Ltd.) was added to 100 parts by mass of the solid content of the acrylic copolymer (Synthesis Example 10). Furthermore, 30 parts by mass of ethyl acetate (manufactured by Fuji Chemicals Co., Ltd.) and 1.0 part by mass of an isocyanate curing agent (Coronate L45, manufactured by Tosoh Corporation) were added, and the mixture was thoroughly stirred to obtain an adhesive solution (c).

[0405] An adhesive solution (c) was applied to the release-treated surface of a 50 μm-thick release PET film and dried at 100°C for 5 minutes to produce a laminated film (c) having a 20 μm-thick hot-melt adhesive layer. Furthermore, the laminated film (c) was overlaid with the hot-melt adhesive layer facing the PET film side of the laminate and cured at 40°C for 48 hours to produce an adhesive tape comprising, in this order, a substrate, a first adhesive layer, an intermediate layer, and a hot-melt adhesive layer.

[0406] (2) Determination of the 180° peel strength of the first adhesive layer to the substrate at 23°C

[0407] The 180° peel strength (N / 25 mm) of the first adhesive layer against the substrate at 23°C was measured in the same manner as in Example 1, except that the laminate described in "(1) Preparation of Adhesive Tape" was used as a test sample. The results are shown in Table 8.

[0408] (3) Measurement of the peak temperature of the loss tangent (tan δ) of the first adhesive layer measured at a frequency of 10 Hz

[0409] The peak temperature (° C.) of the loss tangent (tan δ) of the first pressure-sensitive adhesive layer measured at a frequency of 10 Hz was measured in the same manner as in Example 1. The results are shown in Table 8.

[0410] (4) Measurement of shear storage modulus of the first adhesive layer at 25°C

[0411] The same operation as in Example 1 was carried out to measure the shear storage modulus (×10 4 The results are shown in Table 8.

[0412] (5) Measurement of the gel fraction of the first adhesive layer

[0413] The gel fraction (mass %) of the first pressure-sensitive adhesive layer was measured in the same manner as in Example 45. The results are shown in Table 8.

[0414] (6) Determination of 180° peel strength of hot melt adhesive layer to SUS at 23°C

[0415] The 180° peel strength (N / 25 mm) of the hot melt adhesive layer to SUS at 23° C. was measured in the same manner as in Example 45, except that the hot melt adhesive layer was used as the measurement object. The results are shown in Table 8.

[0416] (7) Determination of 180° peel strength of hot melt adhesive layer to SUS at 23°C after heating

[0417] The resulting adhesive tape was cut into a size of 25 mm wide by 100 mm long. A 23 μm-thick PET film ("FE2002" manufactured by Futamura Chemical Co., Ltd.) was used as a backing for the first adhesive layer. The hot-melt adhesive layer was then pressure-bonded to a SUS plate (SUS304 plate that had been cleaned with ethanol and dry-erased) at 150°C under a pressure of 0.1 MPa for 10 minutes. The plate was then air-cooled to produce a test sample. The resulting test sample was subjected to a 180° peel test using a tensile testing machine ("Tensilon" manufactured by ORIENTEC Co., Ltd.) at 23°C, 50% RH, and a peel speed of 300 mm / min in accordance with JIS Z0237. The adhesive tape was peeled from the SUS plate to measure the 180° peel strength (N / 25 mm) of the hot-melt adhesive layer at 23°C after heating. The results are shown in Table 8.

[0418] (Examples 84-85)

[0419] In the above "(1) Preparation of Adhesive Tape," except that the composition and thickness of each layer were changed as shown in Table 8, an adhesive tape was prepared and measured in the same manner as in Example 83. The results are shown in Table 8. In Example 85, a laminated film (c) was prepared by directly applying 100 parts by mass of chloroprene rubber ("575F," manufactured by CEMEDINE) to the release-treated surface of a 50 μm thick release PET film to form a hot-melt adhesive layer.

[0420] (Examples 86 to 88)

[0421] In the above "(1) Preparation of Adhesive Tape," laminated film (a) and laminated film (c) were stacked with the first adhesive layer and the hot-melt adhesive layer facing each other and cured at 40°C for 48 hours to produce an adhesive tape. Furthermore, in the above "(2) Measurement of 180° Peel Strength of the First Adhesive Layer from a Substrate at 23°C," laminated film (a) was used in place of the adhesive tape and the measurement was performed in the same manner as in Example 1. Adhesive tapes were produced and measured in the same manner as in Example 83, except that the laminated film (a) was used instead of the adhesive tape. The results are shown in Table 8. Laminated film (c) was produced by directly applying the base polymers of the hot-melt adhesive layer shown in Table 8 onto the release-treated surface of a 50 μm thick release PET film to form a hot-melt adhesive layer.

[0422] [Table 3]

[0423]

[0424] [Table 4]

[0425]

[0426] [Table 5]

[0427]

[0428] [Table 6]

[0429]

[0430] [Table 7]

[0431]

[0432] [Table 8]

[0433]

[0434] [Table 9]

[0435]

[0436] <Evaluation>

[0437] The pressure-sensitive adhesive tapes obtained in Examples and Comparative Examples were evaluated by the following methods. The results are shown in Tables 10 to 15.

[0438] (1) Maintaining performance

[0439] (1-1) offset

[0440] The resulting adhesive tape was cut into 25 mm wide strips and then applied to a SUS plate (SUS304 plate that had been cleaned with ethanol and dry-erased) using a 2 kg rubber roller, which was reciprocated once at a speed of 300 mm / min. Next, a cut was made in the adhesive tape to create a bonding area of ​​25 mm x 25 mm. The tape was then left to stand at 23°C for 20 minutes to prepare a test sample. The prepared test sample was placed in an 80°C oven and heated for a further 20 minutes. The sample was then dried under conditions of 80°C and 50% RH. Figure 1 As shown, a 1 kg weight was suspended and a load was applied in the shear direction. Using a graduated magnifying glass, the amount of displacement (mm) from the cut position was measured one hour after the load was applied. Note that for Examples 83 to 88, which had a hot-melt adhesive layer on the outermost surface, the cuts were made in the adhesive tapes and then heat-cured at 150°C and 0.1 MPa for 10 minutes to produce test samples.

[0441] The obtained displacement amount (mm) was used to evaluate the holding performance of the pressure-sensitive adhesive tape according to the following criteria.

[0442] ◎: The offset is 0.5 mm or less.

[0443] ○: The offset amount is greater than 0.5 mm and 1.0 mm or less.

[0444] △: The offset amount is greater than 1.0 mm and 2.0 mm or less.

[0445] ×: The offset is greater than 2.0 mm.

[0446] (1-2) The position where the offset occurs

[0447] After the adhesive tape holding test in the above “(1-1) Amount of Displacement”, the adhesive tape in the test sample was visually observed, and the position where the displacement occurred was determined according to the following criteria.

[0448] A: An offset occurred between the SUS and the adhesive layer in contact with the SUS.

[0449] B: Misalignment occurred between the substrate and the first pressure-sensitive adhesive layer.

[0450] C: The first adhesive layer or the second adhesive layer was offset.

[0451] From the viewpoint of adhesion reliability between the substrate and the adherend at high temperatures, this evaluation is preferably determined as "C", but even if this evaluation is "B", the pressure-sensitive adhesive tape of the present invention can be used without problems.

[0452] (2) Contamination of adherends

[0453] After the adhesive tape retention test described in "(1) Retention Performance" above, the surface from which the adhesive tape was peeled was measured using a scanning X-ray photoelectron spectroscopy analyzer ("PHI 5000 VersaProbe II," manufactured by Ulvac-Phi Corporation) to measure the silicon atom concentration (at %) on the surface of the SUS plate from which the adhesive tape was peeled. XPS measurement was performed under the following conditions.

[0454] <Measurement conditions>

[0455] X-ray source: monochromated AlKα (1486.6 eV)

[0456] Spectrometer: Electrostatic concentric hemispherical analyzer

[0457] Photoelectron extraction angle: 45 degrees

[0458] Charge neutralization: Yes

[0459] X-ray beam diameter: 200 μm

[0460] Pass energy: 117eV

[0461] Using the obtained silicon atom concentration (at %), the contamination property of the adhesive tape on the adherend was evaluated according to the following criteria.

[0462] ○: Silicon atom concentration is 0.1 at % or less.

[0463] Δ: The silicon atom concentration is greater than 0.1 at % and not more than 1.0 at %.

[0464] ×: Silicon atom concentration is greater than 1.0 at %.

[0465] (3) Reprocessability

[0466] The resulting adhesive tape was cut into pieces measuring 25 mm wide by 100 mm long. The second adhesive layer was then pressure-bonded to a SUS plate (SUS304 plate that had been cleaned with ethanol and dry-erased) using a 2 kg rubber roller, moving it back and forth once at a speed of 300 mm / min. The tape was then allowed to stand for 20 minutes in an environment of 23°C and 50% RH for curing, producing a test sample.

[0467] The obtained test samples were subjected to a 180° peel test in accordance with JIS Z0237 using a tensile testing machine (manufactured by ORIENTEC, "Tensilon") at 23°C, 50% RH, and a peel rate of 300 mm / min. The adhesive tape was peeled from the SUS plate, and the reworkability of the adhesive tape was evaluated according to the following criteria.

[0468] ◯: The adhesive tape can be peeled off without breaking, and no residue is generated on the SUS.

[0469] △: The adhesive tape could be peeled off without breaking, but residue on the SUS was generated.

[0470] ×: The adhesive tape was broken during peeling.

[0471] Even if the evaluation is "x", the pressure-sensitive adhesive tape of the present invention can be used without problems depending on the intended use.

[0472] (4) Fitting the business

[0473] The resulting adhesive tape was cut into pieces measuring 25 mm wide by 100 mm long. The release PET film protecting the first adhesive layer of the cut tape was peeled off, and the first adhesive layer was pressed onto a polytetrafluoroethylene sheet (Yodogawa Hu-Tech, "Yodofluon") measuring 50 mm wide by 200 mm long by 2 mm thick, using a 2 kg rubber roller, reciprocating once at a speed of 300 mm / min, to produce a laminate. Furthermore, the release PET film protecting the hot-melt adhesive layer of the resulting laminate was peeled off, and the hot-melt adhesive layer was bonded using a 5 mm diameter SUS probe at 23°C, a pressure of 98 gf, a pressing speed of 100 mm / sec, and a pressing time of 10 seconds. After standing for 10 minutes at 23°C and 50% RH, the hot-melt adhesive layer was peeled off from the SUS at a separation speed of 5 mm / sec. The surface of the hot-melt adhesive layer and the bonding surface between the polytetrafluoroethylene sheet and the first adhesive layer were observed visually and under an optical microscope.

[0474] The hot melt adhesive layer was observed to have no surface roughness and the adhesive tape was not peeled from the polytetrafluoroethylene plate. The first adhesive layer was peeled from the polytetrafluoroethylene plate during the lamination operation. The lamination workability was evaluated as "X".

[0475] Note that this evaluation was performed only on the pressure-sensitive adhesive tapes having a hot-melt pressure-sensitive adhesive layer, namely, Examples 83 to 88.

[0476] [Table 10]

[0477]

[0478] [Table 11]

[0479]

[0480] [Table 12]

[0481]

[0482] [Table 13]

[0483]

[0484] [Table 14]

[0485]

[0486] [Table 15]

[0487]

[0488] Industrial applicability

[0489] The present invention provides an adhesive tape that exhibits excellent holding performance, minimizes adherend contamination, and facilitates fluororesin bonding. Furthermore, the present invention provides a chemical tank to which the adhesive tape is affixed. Furthermore, the present invention provides a method for manufacturing a chemical tank using the adhesive tape.

[0490] Description of Reference Numerals

[0491] 1 adhesive tape

[0492] 2 SUS304 plate

[0493] 3 1kg weight

Claims

1. An adhesive tape, characterized in that: comprising a substrate and a first adhesive layer adjacent to one surface of the substrate, The substrate comprises a resin film containing a fluororesin, The first adhesive layer contains a base polymer P1 and a tackifying resin, The base polymer P1 includes at least one selected from the group consisting of a (meth)acrylic copolymer and a styrene elastomer.

2. The adhesive tape according to claim 1, comprising the substrate, the first adhesive layer, an intermediate layer, and a second adhesive layer in this order. The second adhesive layer contains a base polymer P2, The base polymer P2 includes at least one selected from the group consisting of a (meth)acrylic copolymer and a styrene elastomer.

3. The adhesive tape according to claim 2, wherein The second adhesive layer has a probe tack of 20 N / 5 mmφ or less as measured under the conditions of 23° C., 98 gf pressure, 100 mm / sec pressure speed, 10 seconds pressure time, and 5 mm / sec separation speed. The adhesive tape according to claim 1 , comprising the substrate, the first adhesive layer, and a hot-melt adhesive layer in this order.

5. The adhesive tape according to claim 1, 2, 3 or 4, wherein In the base polymer P1, the (meth)acrylic copolymer comprises a structural unit derived from an alkyl (meth)acrylate having an alkyl group having 4 to 12 carbon atoms at the ester terminal, and at least one structural unit selected from a structural unit derived from a carboxyl group-containing (meth)acrylate and a structural unit derived from a hydroxyl group-containing (meth)acrylate. The adhesive tape according to claim 5 , wherein The alkyl (meth)acrylate having an alkyl group with 4 to 12 carbon atoms at the ester terminal includes an alkyl (meth)acrylate having an alkyl group with 6 to 8 carbon atoms at the ester terminal.

7. The adhesive tape according to claim 5 or 6, wherein The alkyl (meth)acrylate having an alkyl group having 4 to 12 carbon atoms at the ester terminal includes n-heptyl (meth)acrylate.

8. The adhesive tape according to claim 6 or 7, wherein In the (meth)acrylic copolymer, the content of the structural unit derived from the (meth)acrylate alkyl ester having an alkyl group having 6 to 8 carbon atoms at the ester terminal is 50% by mass or more and 99.5% by mass or less.

9. The adhesive tape according to claim 1, 2, 3, 4, 5, 6, 7 or 8, wherein The tackifying resin comprises: a tackifying resin T1 having at least one structural unit (A) selected from the group consisting of a structural unit (A-1), a structural unit (A-1'), a structural unit (A-2), a structural unit (A-2'), a structural unit (A-3), a structural unit (A-3'), a structural unit (A-4), and a structural unit (A-4') represented by the following formula; Where 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; n and l represent an integer of 2 or more and 4 or less, n' and l' represent an integer of 2 or more and 5 or less; m and k represent an integer of 1 or more and 4 or less, m' and k' represent an integer of 1 or more and 5 or less; it should be noted that Indicates a connection part.

10. The adhesive tape according to claim 9, wherein The tackifier resin T1 further includes a structural unit (B) derived from at least one monomer (b) selected from a terpene-based monomer and a vinyl-based monomer.

11. The adhesive tape according to claim 9 or 10, wherein The content of the tackifier resin T1 is 5 parts by mass or more and 50 parts by mass or less relative to 100 parts by mass of the base polymer P1.

12. The adhesive tape according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or 11, wherein The tackifying resin includes at least one tackifying resin T2 selected from the group consisting of rosin ester resins, terpene resins, terpene phenol resins, and petroleum resins.

13. The adhesive tape according to claim 12, wherein The tackifying resin T2 includes a rosin ester resin.

14. The adhesive tape according to claim 12 or 13, wherein The softening temperature of the tackifier resin T2 is 50° C. or higher and 200° C. or lower.

15. The adhesive tape according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13 or 14, wherein The first adhesive layer does not contain an organic silicon compound, or the content of the organic silicon compound in the first adhesive layer is 3.0% by mass or less.

16. The adhesive tape according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 or 15, wherein The first adhesive layer has a 180° peel strength from the substrate of 2.5 N / 25 mm or more at 23°C.

17. The adhesive tape according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or 16, wherein The first pressure-sensitive adhesive layer has a loss tangent tan δ measured at a frequency of 10 Hz in a dynamic viscoelasticity measurement, and has a peak in a temperature range of -30°C to 15°C.

18. The adhesive tape according to claim 17, wherein The shear storage modulus of the first adhesive layer at 25° C. measured at a frequency of 10 Hz in a dynamic viscoelasticity measurement was 1.0×10 4 Pa or more and 5.0×10 5 Pa or less, and the loss tangent tan δ of the first pressure-sensitive adhesive layer measured at a frequency of 10 Hz in a dynamic viscoelasticity measurement has a peak in a temperature range of -30°C to 15°C.

19. The adhesive tape according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17 or 18, wherein The first pressure-sensitive adhesive layer has a gel fraction of 15% by mass or more and 70% by mass or less.

20. The adhesive tape according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18 or 19, wherein The thickness of the first adhesive layer is 20 μm or more and 500 μm or less.

21. The adhesive tape according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20, wherein The resin film containing a fluororesin includes at least one selected from the group consisting of a glass cloth impregnated with a fluororesin and a laminated film in which a fluororesin layer and a glass cloth layer are laminated.

22. The adhesive tape according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 or 21, wherein The thickness of the substrate is 50 μm or more and 5000 μm or less.

23. The adhesive tape according to claim 2 or 3, wherein The second adhesive layer of the adhesive tape has a 180° peel strength with respect to SUS at 23° C. of 8.0 N / 25 mm or less.

24. The adhesive tape according to claim 2, 3 or 23, wherein The second adhesive layer has a thickness of 20 μm or more and 500 μm or less.

25. The adhesive tape according to claim 2, 3, 23 or 24, wherein The intermediate layer includes at least one selected from the group consisting of polyester resin, polyimide resin, polyolefin resin, polyurethane resin, glass fiber, carbon fiber, and metal.

26. The adhesive tape according to claim 2, 3, 23, 24 or 25, wherein The middle layer has a foamed structure.

27. The adhesive tape according to claim 4, wherein When the hot melt adhesive layer is pressure-bonded to SUS at 150° C. and 0.1 MPa for 10 minutes, the adhesive tape exhibits a 180° peel strength of 5.0 N / 25 mm or more to SUS at 23° C.

28. The adhesive tape according to claim 4 or 27, wherein The hot melt adhesive layer contains a base polymer P3, The base polymer P3 includes at least one selected from the group consisting of (meth)acrylic copolymers, styrene elastomers, ethylene-vinyl acetate copolymers, chloroprene rubber, nitrile rubber, polyurethane resins, polyamide resins, polyolefin resins, polyester resins, and epoxy resins.

29. The adhesive tape according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27 or 28, which is used for protecting an adherend.

30. The adhesive tape according to claim 29, which is used to protect an adherend from chemical liquids. 31 . The adhesive tape according to claim 30 , which is used for lining a tank body in a chemical tank for semiconductors or a chemical tank for the chemical industry.

32. A liquid medicine tank, wherein: The adhesive tape according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30 or 31 is affixed to the inner surface of the can.

33. A method for manufacturing a chemical liquid tank for semiconductors or a chemical liquid tank for the chemical industry, comprising the step of adhering the adhesive tape described in claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30 or 31 to the inner surface of the tank body in the chemical liquid tank.

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