Adhesive tape and method of manufacturing the same

Abstract

The objective of this invention is to provide a thin adhesive tape with low toluene and n-hexane content but stable adhesive strength. An adhesive tape has a substrate and an adhesive layer disposed on at least one of the substrate, wherein the thickness of the adhesive layer is 0.2 μm or more and 5.3 μm or less, the toluene content of the adhesive layer is 1000 ppm or less, the n-hexane content of the adhesive layer is 1000 ppm or less, and the minimum value of the 180-degree peel adhesion force of the adhesive tape on a matte layer surface with a maximum profile height (Rz) of 5.2 μm and an arithmetic mean roughness (Ra) of 0.5 μm is 0.5 N / 20 mm or more when measured 10 times, and the minimum value of the 10 measurements is 0.4 times or more the average value of the 10 measurements.

Description

Technical Field

[0001] This invention relates to adhesive tape and its manufacturing method. Background Technology

[0002] Adhesive tape is widely used to fasten components that make up electronic devices and other items together.

[0003] In recent years, in particular, there has been a strong demand for high functionality and thinness in portable electronic devices such as personal computers, digital cameras, electronic notebooks, mobile phones, PHS devices, smartphones, gaming devices, and e-books. Therefore, in the manufacturing of these portable electronic devices, there is a requirement for the thinness of the main components, and further thinning of the adhesive tape used to fix these components.

[0004] For example, Patent Document 1 describes a colored adhesive film comprising a release film, an adhesive layer, a resin film, a coloring layer, and a roughening layer. In the aforementioned colored adhesive film, the adhesive component is dissolved in toluene to prepare the adhesive solution.

[0005] To achieve stable adhesion, a uniform thickness of the adhesive layer is required. Toluene and n-hexane are known solvents that can achieve uniform coating thickness. However, these solvents are known to have environmental and health effects, and it is desirable to reduce their content in the product. Therefore, there is a strong demand for the rapid supply of thin adhesive tapes with low toluene and n-hexane content but stable adhesive strength. Existing technical documents Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2018-104642 Summary of the Invention The problem that the invention aims to solve

[0007] The objective of this invention is to solve the aforementioned problems and achieve the following objective: to provide a thin adhesive tape with low toluene and n-hexane content but stable adhesive strength. Methods for solving problems

[0008] In order to achieve the above objectives, the inventors have conducted repeated and in-depth research and found that a thin adhesive tape with low toluene and n-hexane content but stable adhesive strength can be provided.

[0009] This invention is based on the aforementioned technical concept, and the means to solve the above-mentioned problems are as follows. That is, <1> A method for manufacturing an adhesive tape, characterized in that it includes an adhesive layer forming step, wherein an adhesive solution having an ethyl acetate content of 50% to 95% by mass, a toluene content of 1% to 1% by mass, a n-hexane content of 1% to 1% by mass, and a solid component concentration of 5% to 20% by mass is disposed on the surface of a substrate to form an adhesive layer with a thickness of 0.5 μm to 5 μm. <2> An adhesive tape, characterized in that, It has a substrate and an adhesive layer disposed on at least one of the substrates. The thickness of the aforementioned adhesive layer is 0.2 μm or more and 5.3 μm or less. The toluene content in the aforementioned adhesive layer is below 1000 ppm. The hexane content of the aforementioned adhesive layer is below 1000 ppm. The minimum value of the 180-degree peel adhesion force of the matte layer surface with a maximum profile height (Rz) of 5.2 μm and an arithmetic mean roughness (Ra) of 0.5 μm in the above adhesive tape is 0.5 N / 20 mm or more when measured 10 times, and the minimum value of the above 10 measurements is more than 0.4 times the average value of the above 10 measurements. Invention Effects

[0010] According to the present invention, a thin adhesive tape with low toluene and n-hexane content but stable adhesive strength can be provided. Detailed Implementation

[0011] (Adhesive tape) As described above, the adhesive tape has a substrate and an adhesive layer, and may further have other layers. The adhesive layer may be disposed on at least one side of the substrate, or on both sides of the substrate.

[0012] <Substrate> The aforementioned substrate can support the aforementioned adhesive layer.

[0013] There are no particular restrictions on the above-mentioned substrates; they can be selected appropriately according to the purpose, with resin-made films being preferred. There are no particular limitations on the resins mentioned above; they can be selected appropriately according to the purpose. Examples include polyesters such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polybutylene terephthalate (PBT); amide resins such as polyamides (nylon) and fully aromatic polyamides (aromatic polyamides); polyacrylate resins such as polybutyl acrylate and polyethyl acrylate; methacrylate resins such as methyl methacrylate (PMMA); polystyrene; and acrylonitrile-styrene copolymers. Styrene-based resins such as ABS resin (acrylonitrile-butadiene-styrene copolymer), polyetheretherketone (PEEK), polyetherketoneketone (PEK), polyethersulfone (PES), polysulfone, polyvinyl chloride (PVC), polyphenylene sulfide (PPS), polyimide (PI), polyamide-imide, polyetherimide (PEI), polyesterimide, polycarbonate (PC), polyacetal, polyaryl ethers (polyphenylene ether, etc.), polyphenylene sulfide, polyarylate, polyaryl, polyurethanes, and epoxy resins. These resins can be used individually or in combination. Among these, polyester is preferred, and polyethylene terephthalate is preferred, considering factors such as thickness accuracy, economy (cost), tensile strength, and processability.

[0014] There are no particular limitations on the type of film made from the aforementioned resin; it can be selected appropriately depending on the purpose, with biaxially stretched films being preferred. By biaxial stretching, high strength can be exhibited.

[0015] There is no particular limitation on the average thickness of the above-mentioned substrate, and it can be appropriately selected according to the purpose. It is preferably 0.5 μm or more and 100 μm or less, more preferably 1.0 μm or more and 12 μm or less, and even more preferably 1.5 μm or more and 2.5 μm or less.

[0016] Regarding the thickness of the aforementioned substrate, the thickness was measured in 0.1 μm units using a "Digimicro MF-501" manufactured by Nikon Corporation. The average thickness of the substrate is the average value obtained by measuring 10 points along the width of the substrate.

[0017] The aforementioned substrates can be commercially available products. Commercially available products that serve as the aforementioned substrates include, for example, Lumirror2F51 (2.0μm) manufactured by Toray Industries, Inc., and K750 (2.0μm) manufactured by Mitsubishi Chemical Corporation.

[0018] <Adhesive layer> The adhesive layer is disposed on at least one of the substrates. That is, the adhesive layer can be disposed on one side of the substrate or on both sides of the substrate. The adhesive layer can be directly connected to one or both sides of the substrate, or it can be provided with other layers in between.

[0019] The adhesive layer described above contains an adhesive and may further contain other components.

[0020] -Adhesive- There are no particular limitations on the adhesives mentioned above, and they can be selected appropriately according to the purpose. For example, well-known adhesives such as acrylic adhesives, rubber adhesives, silicone adhesives, urethane adhesives, polyester adhesives, styrene-diene block copolymer adhesives, vinyl alkyl ether adhesives, polyamide adhesives, fluorinated adhesives, creep-modified adhesives, and radiation-cured adhesives can be used. Among these, acrylic adhesives offer superior bonding reliability and are therefore preferred.

[0021] Examples of acrylic adhesives include substances containing acrylic polymers. Examples of the aforementioned acrylic polymers include polymers obtained by polymerizing monomer components containing monomers such as alkyl methacrylates (meth)acrylic acid monomers.

[0022] Examples of the aforementioned alkyl methacrylates include methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, pentyl methacrylate, hexyl methacrylate, heptyl methacrylate, octyl methacrylate, 2-ethylhexyl methacrylate, isooctyl methacrylate, nonyl methacrylate, isononyl methacrylate, decyl methacrylate, isodecanyl methacrylate, undecyl methacrylate, dodecyl methacrylate, tridecyl methacrylate, tetradecyl methacrylate, pentadecyl methacrylate, hexadecyl methacrylate, heptadecanyl methacrylate, octadecyl methacrylate, nonadecanyl methacrylate, and eicosyl methacrylate. The aforementioned alkyl methacrylates can be used alone or in combination of two or more. Among these, alkyl methacrylates are preferably those in which the alkyl group has 1 or more and 20 or less carbon atoms, more preferably those in which the alkyl group has 4 or more and 18 or less carbon atoms, and even more preferably those in which the alkyl group has 4 or more and 9 or less carbon atoms. Examples of alkyl groups include straight-chain or branched alkyl groups. It should be noted that in this specification, "(meth)acrylate alkyl ester" refers to alkyl acrylate or alkyl methacrylate.

[0023] Among these, butyl methacrylate, isooctyl methacrylate, 2-ethylhexyl methacrylate, isononyl methacrylate, and ethyl methacrylate are preferred as alkyl methacrylates, as described above, as they readily ensure suitable adhesive strength.

[0024] Relative to the total amount of the (meth)acrylic acid monomers mentioned above, the alkyl methacrylic acid esters mentioned above are preferably used in the range of 90% by mass or more and 99% by mass or less, and more preferably in the range of 90% by mass or more and 96% by mass or less for the purpose of easily ensuring suitable adhesive strength.

[0025] In addition to alkyl methacrylates, monomers with polar groups such as hydroxyl, carboxyl, and amide groups can also be used among the above-mentioned (meth)acrylic acid monomers. Specifically, examples include: monomers with carboxyl groups such as (meth)acrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, and isocrotonic acid, or their anhydrides; monomers with sulfonic acid groups such as sodium vinyl sulfonate; monomers with cyano groups such as acrylonitrile; monomers with amide groups such as acrylamide, methacrylamide, N-vinylpyrrolidone, and N,N-dimethyl(meth)acrylamide; monomers with hydroxyl groups such as (meth)acrylic acid hydroxyalkyl ester and glycerol dimethacrylate; monomers with amino groups such as (meth)acrylic acid aminoethyl ester and (meth)acryloylmorpholine; and monomers with amide groups such as cyclohexylmaleimide and isopropylmaleimide. Monomers with amino groups; epoxy groups such as glycidyl methacrylate and methyl glycidyl methacrylate; isocyanate groups such as 2-methacryloyloxyethyl isocyanate; and monomers such as triethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, ethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and divinylbenzene. These can be used individually or in combination.

[0026] In addition to (meth)acrylic acid monomers, aromatic vinyl compounds such as styrene and substituted styrene, olefins such as ethylene, propylene, and butadiene, vinyl esters such as vinyl acetate, and vinyl chloride can also be used as monomers.

[0027] The aforementioned acrylic polymer can be manufactured by polymerizing monomers using methods such as solution polymerization, bulk polymerization, suspension polymerization, and emulsion polymerization. From the perspective of improving the production efficiency of acrylic polymers, solution polymerization is preferred.

[0028] There are no particular limitations on the solution polymerization method described above, and it can be appropriately selected according to the purpose. For example, a method can be given by mixing and stirring the monomer, polymerization initiator and organic solvent at a temperature preferably above 40°C and below 90°C to carry out free radical polymerization.

[0029] There are no particular limitations on the above-mentioned polymerization initiators, and they can be appropriately selected according to the purpose. For example, peroxides such as benzoyl peroxide and lauryl peroxide, azo-based thermal polymerization initiators such as azobisisobutyl nitrile, acetophenone-based photopolymerization initiators, benzoin ether-based photopolymerization initiators, benzyl ketal-based photopolymerization initiators, acylphosphine oxide-based photopolymerization initiators, benzoin-based photopolymerization initiators, and benzophenone-based photopolymerization initiators can be cited. Regarding the acrylic polymer obtained by the above method, for example, if it is manufactured by solution polymerization, it can be in a state of being dissolved or dispersed in an organic solvent.

[0030] From the perspective of having excellent adhesion even in thin layers, the acrylic polymer obtained by the above method preferably has a weight-average molecular weight of 300,000 or more and 1,200,000 or less, more preferably has a weight-average molecular weight of 400,000 or more and 1,100,000 or less, and even more preferably has a weight-average molecular weight of 500,000 or more and 1,000,000 or less.

[0031] The weight-average molecular weight mentioned above refers to the value calculated by gel permeation chromatography (GPC) and conversion to standard polystyrene. Specifically, the weight-average molecular weight was determined using a GPC apparatus (HLC-8329GPC) manufactured by Tosoh Corporation under the following conditions. Sample concentration: 0.5% by mass (tetrahydrofuran solution) Sample injection volume: 100 μL Eluent: Tetrahydrofuran Flow rate: 1.0 mL / min Measurement temperature: 40℃ Main column: 2 TSKgel GMHHR-H(20) Protective pillar: TSKgel HXL-H Detector: Differential refractometer Standard polystyrene has a weight-average molecular weight of 10,000 or more but less than 20 million (manufactured by Tosoh Corporation).

[0032] -Other components in the above adhesive layer- There are no particular restrictions on other components in the adhesive layer mentioned above, and they can be selected appropriately according to the purpose. Examples include tackifying resins, colorants, crosslinking agents (curing agents), softeners, plasticizers, fillers, anti-aging agents, and residual solvents.

[0033] From the perspective of providing stable adhesive strength, the above-mentioned adhesive layer preferably contains a tackifying resin.

[0034] There are no particular limitations on the aforementioned tackifying resins, and they can be appropriately selected according to the purpose. Examples include rosin-based tackifying resins, polymerized rosin-based tackifying resins, polymerized rosin ester-based tackifying resins, rosin phenol-based tackifying resins, stabilized rosin ester-based tackifying resins, disproportionated rosin ester-based tackifying resins, hydrogenated rosin ester-based tackifying resins, terpene-based tackifying resins, terpene phenol-based tackifying resins, and petroleum resin-based tackifying resins such as styrene-based tackifying resins.

[0035] From the perspective of having excellent adhesion even in thin layers, it is preferable to use a combination of rosin-based and petroleum resin-based tackifying resins as the aforementioned tackifying resins. Regarding the aforementioned rosin-based and petroleum resin-based tackifying resins, from the perspective of obtaining even better adhesion even in thin layers, it is particularly preferable to use them in combination with the aforementioned acrylic polymers, and more preferably in combination with acrylic polymers obtained by polymerizing monomers containing (meth)butyl acrylate.

[0036] From the perspective of further improving the initial adhesion of the adhesive layer, it is preferable to use a tackifying resin that is liquid at room temperature as the aforementioned tackifying resin. There are no particular limitations on the aforementioned tackifying resins that are liquid at room temperature; they can be selected appropriately depending on the purpose. Examples include processing oils, polyester plasticizers, low molecular weight liquid rubbers such as polybutene, and terpene phenolic resins. Commercially available products include YP-90L manufactured by YASUHARA CHEMICAL Co., Ltd.

[0037] From the perspective of having even better adhesive strength, the tackifying resin is preferably used in the range of 20 parts by weight or more and 60 parts by weight or less, more preferably in the range of 30 parts by weight or more and 55 parts by weight or less, relative to 100 parts by weight of the adhesive.

[0038] There are no particular restrictions on the colorants mentioned above; they can be selected appropriately according to the purpose, such as pigments.

[0039] There are no particular limitations on the crosslinking agents mentioned above, and they can be selected appropriately according to the purpose. From the perspective of imparting stable adhesive strength, isocyanate crosslinking agents or epoxy crosslinking agents are preferred, and isocyanate crosslinking agents are more preferred. That is, from the perspective of imparting stable adhesive force, the adhesive layer preferably has a crosslinking structure derived from an isocyanate crosslinking agent or an epoxy crosslinking agent, and more preferably has a crosslinking structure derived from an isocyanate crosslinking agent.

[0040] There are no particular limitations on the crosslinking agents used for the aforementioned isocyanates, and they can be appropriately selected according to the purpose. For example, toluene diisocyanate, naphthyl-1,5-diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate, phenylenediamine diisocyanate, trimethylolpropane-modified toluene diisocyanate, etc., can be used. Toluene diisocyanate adducts such as toluene diisocyanate and trimethylolpropane-modified toluene diisocyanate are preferred. The aforementioned toluene diisocyanate adducts refer to substances that have a structure derived from toluene diisocyanate in their molecules. Commercially available products include, for example, Coronate L (manufactured by Nippon Polyurethane Kogyo Co., Ltd.).

[0041] When using the above-mentioned isocyanate crosslinking agent, it is preferable to use an acrylic polymer having hydroxyl groups as the acrylic polymer. Among the aforementioned acrylic polymers containing hydroxyl groups, monomers used in their manufacture may include, for example, 2-hydroxyethyl methacrylate, 4-hydroxybutyl methacrylate, and 6-hydroxyhexyl methacrylate, with 2-hydroxyethyl methacrylate and 4-hydroxybutyl methacrylate being more preferred.

[0042] There are no particular limitations on the epoxy crosslinking agents mentioned above, and they can be selected appropriately according to the purpose. For example, TETRAD X and TETRAD C manufactured by Mitsubishi Gas Chemical Co., Ltd., or E-05X manufactured by Soken Chemical Co., Ltd. can be cited.

[0043] When using the above-mentioned epoxy crosslinking agent, it is preferable to use an acrylic polymer having acid groups as the acrylic polymer. Among the above-mentioned acrylic polymers with acid groups, the monomers used in their manufacture are preferably (meth)acrylic acid, acrylic dimer, itaconic acid, crotonic acid, maleic acid, maleic anhydride, etc., and more preferably (meth)acrylic acid.

[0044] The content of the crosslinking agent in the adhesive layer is not particularly limited and can be appropriately selected according to the purpose. It is preferably 0.01 parts by mass or more and 10 parts by mass or less, more preferably 0.1 parts by mass or more and 10 parts by mass or less, and even more preferably 0.5 parts by mass or more and 5 parts by mass or less, relative to 100 parts by mass of the adhesive solid component.

[0045] Examples of residual solvents include those used in the adhesive solution (coating liquid) of the adhesive layer, such as ethyl acetate, toluene, and n-hexane. However, since toluene and n-hexane are not actually used as the solvents described above, the residual solvent is the amount in the adhesive layer described below.

[0046] The content of toluene in the adhesive layer is not particularly limited as long as it is 1000 ppm or less, and can be appropriately selected according to the purpose. It is preferably 500 ppm or less, more preferably 100 ppm or less, even more preferably 10 ppm or less, and particularly preferably below the detection limit.

[0047] The content of the aforementioned n-hexane in the adhesive layer is not particularly limited as long as it is 1000 ppm or less, and can be appropriately selected according to the purpose. It is preferably 500 ppm or less, more preferably 100 ppm or less, even more preferably 10 ppm or less, and particularly preferably below the detection limit.

[0048] In the double-sided adhesive tape, the content of toluene in the adhesive layer and the content of n-hexane in the adhesive layer are determined by the following method. Cut the specified size (area: 10cm²) from the double-sided adhesive tape. 2 To make a sample, peel off the liner from one adhesive side of the sample and attach the aluminum foil to the adhesive side. Peel off the release liner covering the other adhesive side, leaving the adhesive side open, and place it into a 20 mL vial, then seal it with a stopper. The vial containing the sample was then heated at 80°C for 30 minutes. 1.0 mL of the heated gas was injected into a gas chromatograph (GC apparatus) using a headspace autosampler to determine the amounts of toluene and n-hexane. The measured values ​​of toluene or n-hexane were then converted into the toluene content (emission amount) [ppm] or n-hexane content (emission amount) [ppm] per unit mass of adhesive in the sample (double-sided adhesive tape). It should be noted that, in the case of single-sided adhesive tape, the measurement was performed without aluminum foil attached to the adhesive side.

[0049] The conditions for gas chromatography are as follows. • Column: DB-FFAP 1.0μm (diameter 0.535mm × 30m) • Carrier gas: He 5.0 mL / min • Column head pressure: 23 kPa (40℃) • Injection port: split (split ratio 12:1, temperature 250℃) • Column temperature: Increase the temperature from 40°C to 250°C at a rate of 10°C / min, and then hold at 250°C for 9 minutes. • Detector: FID (temperature 250℃)

[0050] The thickness of the adhesive layer is not particularly limited as long as it is 0.2 μm or more and 5.3 μm or less, and can be appropriately selected according to the purpose. From the perspective of imparting stable adhesive force, it is preferred to be 0.5 μm or more and 5.0 μm or less, more preferably 1.2 μm or more and 4.0 μm or less, further preferably 1.5 μm or more and 3.0 μm or less, particularly preferably 1.7 μm or more and 3.0 μm or less, and most preferably 2.0 μm or more and 3.0 μm or less.

[0051] There is no particular limitation on the average thickness of the adhesive layer, which can be appropriately selected according to the purpose. From the perspective of imparting stable adhesive force, it is preferably 1.0 μm or more and 5.0 μm or less, more preferably 1.5 μm or more and 4.0 μm or less, and even more preferably 2.0 μm or more and 3.5 μm or less.

[0052] Regarding the thickness of the aforementioned adhesive layer, the thickness was measured in 0.1 μm units using a "Digimicro MF-501" manufactured by Nikon Corporation. First, the thickness (I) of the adhesive tape with the spacer (release layer) was measured. Next, the adhesive in the same area was wiped off with ethyl acetate, and the thickness (II) of that area was measured. Then, the thickness of the adhesive layer was calculated as "thickness (I) - thickness (II)". The average thickness of the substrate is the average value obtained by measuring 10 points along the width of the substrate.

[0053] <Other Layers> There are no particular restrictions on the other layers mentioned above, and they can be appropriately selected according to the purpose. Examples include release layer, resin layer, light-shielding layer, light-reflecting layer, conductive layer, thermally conductive layer, electromagnetic wave shielding layer, etc. There are no particular restrictions on the position of the other layers in the adhesive tape, and they can be selected appropriately according to the purpose.

[0054] -Peeling Layer- The release layer can be disposed on the side of the adhesive layer opposite to the substrate. The release layer can be directly connected to the adhesive layer on the side opposite to the substrate, or it can be provided with other layers in between.

[0055] There are no particular limitations on the release layer mentioned above, and it can be selected appropriately according to the purpose. For example, it can be a release layer for paper such as kraft paper, cellophane, and fiberless paper, resin films such as polyethylene, polypropylene (OPP, CPP), and polyethylene terephthalate, laminated paper formed by laminating the above-mentioned paper with resin films, and materials for which the above-mentioned paper has been subjected to gap filling treatment with clay or polyvinyl alcohol, etc., and for which a silicone resin or similar material has been applied to one or both sides. Among these, from the perspective of enabling the adhesive tape to have uniform thickness, a film formed by biaxial stretching of polyethylene terephthalate, which has excellent thickness uniformity, is preferred.

[0056] There is no particular limitation on the average thickness of the release layer, which can be appropriately selected according to the purpose. Preferably, it is 6 μm or more and 100 μm or less, more preferably 12 μm or more and 75 μm or less, further preferably 16 μm or more and 50 μm or less, particularly preferably 23 μm or more and 38 μm or less, and most preferably 23 μm or more and 26 μm or less. If a thin release layer is used, the adhesive thickness is easier to control. If it is too thin, wrinkles are likely to occur during adhesive coating.

[0057] The thickness of the release layer was measured in the same manner as the thickness of the substrate.

[0058] The minimum value of the 180-degree peel adhesion force of the matte layer surface with a maximum profile height (Rz) of 5.2 μm and an arithmetic mean roughness (Ra) of 0.5 μm in the above-mentioned adhesive tape is 0.5 N / 20 mm or more when measured 10 times. There is no particular limitation as long as the minimum value of the above-mentioned 10 measurements is more than 0.4 times the average value of the above-mentioned 10 measurements, and it can be appropriately selected according to the purpose.

[0059] The minimum value for measuring the 180-degree peel adhesion force of the matte layer surface with a maximum profile height (Rz) of 5.2 μm and an arithmetic mean roughness (Ra) of 0.5 μm in 10 tests is preferably 0.5 N / 20 mm or more, more preferably 0.8 N / 20 mm or more, further preferably 0.9 N / 20 mm or more, particularly preferably 1.0 N / 20 mm or more, and most preferably 1.5 N / 20 mm or more.

[0060] The minimum value of the 180-degree peel adhesion force of the matte layer surface with a maximum profile height (Rz) of 5.2 μm and an arithmetic mean roughness (Ra) of 0.5 μm in the above-mentioned adhesive tape is preferably at least 0.5 times the average value of the above-mentioned 10 measurements, and more preferably at least 0.6 times the average value of the above-mentioned 10 measurements.

[0061] The 180-degree peel bond strength of the matte layer surface of the adhesive tape, which has a maximum profile height (Rz) of 5.2 μm and an arithmetic mean roughness (Ra) of 0.5 μm, was measured using the following method. The aforementioned matte layer surface is formed by sanding one side of the Lumirror X30 (38μm) black polyester film manufactured by Toray Industries, Inc.

[0062] (1) A test board is prepared by fixing the non-frosted side (the other side) of a black polyester film manufactured by Toray Industries, Inc. (Lumirror X30, 38μm) with a frosted side to an aluminum plate (0.5mm) using double-sided tape (DIC Corporation #8603TNW-10-4). (2) The test sample (the adhesive tape of the present invention) is cut into pieces with a width of 20 mm and a length of 100 mm relative to the flow direction (length direction) to make a test piece. In the case of double-sided tape, a PET film with a thickness of 25 μm is pasted on the opposite side of the test surface. (3) In an atmosphere of 23℃ and 50% relative humidity, the test piece is subjected to one round-trip pressure at a speed of 300mm / min using a 2Kg rubber roller on the test plate. (4) For the test piece after the pressurization is completed, place it in an atmosphere of 23°C and 50% relative humidity for 5 minutes. (5) After the static period, place the test plate in one chuck of the tensile testing machine and clamp the clamping part of the test piece in another chuck. Then, peel it off from the test plate at a speed of 100 mm / min in a 180° direction under an atmosphere of 23°C and 50% relative humidity, and measure the adhesion force relative to the surface of the matte layer.

[0063] Regarding the maximum profile height (Rz) and arithmetic mean roughness (Ra) of the above-mentioned matte layer surface, in accordance with JISB0601:2013, a 3D color laser scanning microscope (Olympus Corporation OLS4100) was used as the test device, and the measurements were taken at 23±2℃, relative humidity 50±10%, microscope magnification 1000x, and threshold λC 800μm. Regarding the maximum profile height (Rz) and arithmetic mean roughness (Ra) of the above-mentioned matte layer surface, surface measurements were performed on any three locations of the above-mentioned matte layer surface (8cm long × 8cm wide, respectively), and the average value of the three measurements was taken as the maximum profile height (Rz) and arithmetic mean roughness (Ra) of the above-mentioned matte layer surface.

[0064] In the above-mentioned adhesive tape, when the shear holding force was measured by applying a load of 100g at 100°C, there is no particular limitation on the offset distance after 24 hours. It can be appropriately selected according to the purpose. From the perspective of imparting stable adhesive force, it is preferred to be less than 2mm, more preferably less than 1mm, further preferably less than 1mm, particularly preferably less than 0.5mm, and most preferably less than 0.1mm.

[0065] In the above adhesive tape, when the shear holding force was measured under a load of 100g at 100°C, the offset distance after 24 hours was measured using the following method. The adhesive tape was cut into 20mm widths, and the adhesive layer on one side was supported by a 50μm thick aluminum foil to serve as a test piece. The strip with the release liner removed from the adhesive tape was used as the test piece. The test piece was then adhered to a clean, smooth stainless steel plate (SUS304) with an adhesion area of ​​20mm × 20mm. A 2kg roller was used to apply pressure to the surface of the plate, moving it back and forth once. The pressurized test piece was then placed at 23°C and 50% relative humidity for 1 hour according to JIS Z-0237. Subsequently, a 100g load was applied in the shear direction at 100°C, and the tape offset distance was measured after 24 hours.

[0066] In the aforementioned adhesive tape, there is no particular limitation on the 180-degree peel adhesion force relative to the SUS surface, and it can be appropriately selected according to the purpose. From the perspective of providing stable adhesion force, it is preferably 3.0N / 20mm or more and 20.0N / 20mm or less, more preferably 3.5N / 20mm or more and 20.0N / 20mm or less, further preferably 4.0N / 20mm or more and 10.0N / 20mm or less, and particularly preferably 4.5N / 20mm or more and 8.0N / 20mm or less.

[0067] The 180-degree peel bond strength of the adhesive tape relative to the SUS surface was measured using the following method. The double-sided adhesive tape is adhered to one side of a 25μm thick polyethylene terephthalate (PET) substrate and then cut into rectangles 20mm wide and 100mm long to create the adhesive tape used as the test sample. It should be noted that the step of adhering the tape to the PET substrate is omitted in the single-sided adhesive tape example. Next, at 23°C and 50% relative humidity, the adhesive tape was adhered to a stainless steel plate (SUS304), and a 2kg roller was used to roll back and forth once on the upper surface of the adhesive tape. The tape was then left to stand for 1 hour at 23°C and 50% relative humidity to produce a test piece made by pressing the adhesive tape and the stainless steel plate (SUS304). Next, using a Tensilon peel tester, with the stainless steel plate (SUS304) constituting the above test piece horizontally fixed, the above adhesive tape was peeled in a 180° direction at a peeling speed of 300 mm / min, and the strength at this time was measured.

[0068] The adhesive tape described above can be manufactured using the method described later (the manufacturing method of the adhesive tape).

[0069] (Manufacturing method of adhesive tape) The above-mentioned method for manufacturing adhesive tape includes an adhesive layer forming process, and may further include other processes.

[0070] -Adhesive layer formation process- The adhesive layer forming process described above involves applying an adhesive solution to the surface of a substrate in a manner that results in an adhesive layer with a thickness of 0.5 μm or more and 5 μm or less to form an adhesive layer.

[0071] The adhesive solution described above can be applied to the substrate or applied to the release layer before being applied to the substrate. That is, the adhesive solution can be applied to the substrate or the release layer to form an adhesive layer with a thickness of 0.5 μm or more and 5 μm or less. The aforementioned substrate is as described in the <Substrate> section of the (adhesive tape) above. The aforementioned release layer is as described in the "-Release Layer-" section of the <Other Layers> of the above (adhesive tape).

[0072] In the above-mentioned adhesive layer forming process, from the perspective of making the adhesive layer uniform in thickness and imparting stable adhesive force, it is preferable to form the adhesive layer with a thickness tolerance of ±0.3μm, and more preferably with a thickness tolerance of ±0.2μm.

[0073] The adhesive solution described above contains an adhesive and a solvent, and may further contain other components. The adhesive described above is as described in the <Adhesive Layer> of the above (adhesive tape).

[0074] As for the solvents mentioned above, there are no particular restrictions as long as the boiling point is above 57°C and below 125°C. The solvent can be selected appropriately according to the purpose. For example, alkyl acetates with a boiling point above 57°C and below 125°C can be appropriately mentioned. Specifically, ethyl acetate can be appropriately mentioned. It should be noted that among the alkyl acetates mentioned above, methyl acetate has a boiling point of 56.9℃, ethyl acetate has a boiling point of 77.1℃, and butyl acetate has a boiling point of 126℃. Therefore, ethyl acetate is suitable as a solvent with a boiling point above 57℃ and below 125℃.

[0075] If the boiling point of the solvent is too low, the concentration of the solid components of the adhesive will change during coating, thus affecting the thickness of the adhesive layer. Furthermore, due to the heat of vaporization during solvent evaporation, the adhesive condenses and contains water (whitening). This water reacts with the crosslinking agent (isocyanate, etc.) and cannot achieve the desired degree of crosslinking, resulting in reduced adhesive properties. In addition, if the boiling point is too high, the drying process will be insufficient, resulting in increased residual solvent and reduced adhesive properties.

[0076] The content of ethyl acetate in the above-mentioned adhesive solution is not particularly limited as long as it is 50% by mass or more and 95% by mass or less, and can be appropriately selected according to the purpose. It is preferably 55% by mass or more and 95% by mass or less, more preferably 60% by mass or more and 95% by mass or less, and even more preferably 70% by mass or more and 95% by mass or less.

[0077] The content of toluene in the above-mentioned adhesive solution is not particularly limited as long as it is 1% by mass or less, and can be appropriately selected according to the purpose. It is preferably 0.5% by mass or less, more preferably 0.1% by mass or less, and even more preferably below the detection limit.

[0078] The content of n-hexane in the above-mentioned adhesive solution is not particularly limited as long as it is 1% by mass or less, and can be appropriately selected according to the purpose. It is preferably 0.5% by mass or less, more preferably 0.1% by mass or less, and even more preferably below the detection limit.

[0079] The content of the hydroxyl-containing compound in the above-mentioned adhesive solution is not particularly limited and can be appropriately selected according to the purpose, preferably 1% by mass or less, more preferably 0.5% by mass or less, further preferably 0.1% by mass or less, and particularly preferably below the detection limit.

[0080] There are no particular limitations on the compounds containing hydroxyl groups mentioned above, and they can be appropriately selected according to the purpose; for example, alcohols such as ethanol can be cited.

[0081] The concentration of the solid component in the adhesive solution is not particularly limited as long as it is 5% by mass or more and 20% by mass or less, and can be appropriately selected according to the purpose. From the perspective of imparting stable adhesive force, it is preferably 7% by mass or more and 15% by mass or less, more preferably 8% by mass or more and 13% by mass or less, and even more preferably 9% by mass or more and 12% by mass or less.

[0082] -Other components in the above adhesive solution- There are no particular restrictions on other components in the above-mentioned adhesive solution, and they can be appropriately selected according to the purpose. Examples include tackifying resins, colorants, crosslinking agents (curing agents), softeners, plasticizers, fillers, anti-aging agents, etc. The aforementioned tackifying resin is as described in the <adhesive layer> of the above-mentioned (adhesive tape). The aforementioned colorant is as described in the <adhesive layer> of the above (adhesive tape). The crosslinking agent described above is as described in the <adhesive layer> of the above (adhesive tape).

[0083] The aforementioned adhesive layer can be formed using known coating methods, such as microgravure coating machines, small-diameter gravure coating machines, die coating machines, comma coating machines, etc. Among these, from the perspective of providing stable adhesion, it is preferable to use a micro-gravure coating machine, a small-diameter gravure coating machine, or a die coating machine.

[0084] The aforementioned micro-gravure coating machine or small-diameter gravure coating machine refers to a gravure roller with a diameter of... Coating machines with a diameter of 300 mm or more and a diameter of less than 300 mm. From the perspective of providing stable adhesion, the groove volume of the gravure roller in the aforementioned micro-gravure coating machine or small-diameter gravure coating machine is preferably 50 cm. 3 / m 2 Above and 100cm 3 / m 2 the following. Example

[0085] The following describes embodiments of the present invention, but the present invention is not limited to these embodiments in any way.

[0086] [Preparation of Adhesives] <Adhesive A> Using 0.2 parts by mass of azobisisobutyronitrile as a polymerization initiator, 97.68 parts by mass of n-butyl acrylate, 2.3 parts by mass of acrylic acid, and 0.02 parts by mass of 4-hydroxybutyl acrylate were subjected to solution polymerization in ethyl acetate solution at 77°C for 8 hours, thereby obtaining an acrylic polymer with a weight average molecular weight of 900,000. Relative to 100 parts by weight of the aforementioned acrylic polymer, 5 parts by weight of "D-135" (manufactured by Arakawa Chemical Industry Co., Ltd., polymerized rosin ester), 20 parts by weight of "KE-100" (manufactured by Arakawa Chemical Industry Co., Ltd., disproportionated rosin ester), and 25 parts by weight of "FTR6100" (manufactured by Mitsui Chemicals Co., Ltd., petroleum resin) were mixed, and ethyl acetate was further added to obtain an adhesive solution with a solid content concentration adjusted to 50% by weight. The above adhesive solution was mixed with 1.1 parts by weight of "NC40" (manufactured by DIC Corporation, an isocyanate crosslinking agent) and stirred to obtain adhesive A.

[0087] <Adhesive B> Using 0.2 parts by mass of azobisisobutyronitrile as a polymerization initiator, 97.98 parts by mass of n-butyl acrylate, 2.0 parts by mass of acrylic acid, and 0.02 parts by mass of 4-hydroxybutyl acrylate were subjected to solution polymerization in ethyl acetate solution at 77°C for 8 hours, thereby obtaining an acrylic polymer with a weight average molecular weight of 900,000. In addition to 100 parts by weight of the aforementioned acrylic polymer, 15 parts by weight of "D-135" (manufactured by Arakawa Chemical Industry Co., Ltd., polymerized rosin ester) and 35 parts by weight of "KE-100" (manufactured by Arakawa Chemical Industry Co., Ltd., disproportionated rosin ester) were mixed, and ethyl acetate was further added to obtain an adhesive solution with a solid content concentration adjusted to 50% by weight. The above adhesive solution was mixed with 1.4 parts by weight of "NC40" (manufactured by DIC Corporation, an isocyanate crosslinking agent) and stirred to obtain adhesive B.

[0088] [Manufacturing of Adhesive Tape] (Example 1) Make the adhesive tape in the following order. Ethyl acetate was added to adhesive A and stirred to prepare an adhesive solution with 90% by mass of ethyl acetate and 10% by mass of solids. This solution was then coated onto a release film using a microgravure coater at a speed of 40 m / min. The coated laminate was sequentially conveyed and passed through seven drying zones for drying, and then laminated onto a 2.0 μm thick PET film (Lumirror 2F51 manufactured by Toray Industries, Inc.) to obtain a single-sided tape. Subsequently, the adhesive solution was similarly coated onto the release film, dried, and then laminated onto the 2.0 μm thick PET film surface of the single-sided tape to obtain a double-sided tape. The number and length of the aforementioned drying areas are 7 areas × 3m each. The temperatures of the aforementioned drying areas, from the first drying area to the seventh drying area, are 60℃, 70℃, 80℃, 90℃, 100℃, 90℃, and 80℃, respectively. The average thickness of the adhesive layer is 1.5 μm. The average thickness is the average value obtained by measuring the tape at 10 points in the width direction.

[0089] (Example 2) Adhesive tape 2 was prepared in the same manner as in Example 1, except that the concentration of solid components in the adhesive solution was 7% by mass instead of 10% by mass.

[0090] (Example 3) The adhesive tape 3 was prepared in the same manner as in Example 1, except that the concentration of the solid components of the adhesive solution was 15% by mass instead of 10% by mass.

[0091] (Example 4) Except that the proportions of solvent in the adhesive solution are 60% by mass of ethyl acetate and 30% by mass of methyl acetate, the adhesive tape 4 is prepared in the same manner as in Example 1.

[0092] (Example 5) Except that the proportions of solvent in the adhesive solution are 60% by mass of ethyl acetate and 30% by mass of butyl acetate, the adhesive tape 5 was prepared in the same manner as in Example 1.

[0093] (Example 6) Except that the proportions of solvent in the adhesive solution are 60% by mass of ethyl acetate and 30% by mass of methyl ethyl ketone, the adhesive tape 6 is prepared in the same manner as in Example 1.

[0094] (Example 7) The adhesive tape 7 is made in the same manner as in Example 1, except that adhesive B is used instead of adhesive A.

[0095] (Example 8) Except that a die-type coating machine is used instead of a microgravure coating machine, the adhesive tape 8 is made in the same manner as in Example 1.

[0096] (Comparative Example 1) The adhesive tape 9 was prepared in the same manner as in Example 1, except that the concentration of the solid components of the adhesive solution was 30% by mass instead of 10% by mass.

[0097] (Comparative Example 2) The adhesive tape 10 was made in the same manner as in Example 1, except that the concentration of the solid component of the adhesive solution was 1% by mass instead of 10% by mass.

[0098] (Comparative Example 3) Except that the proportions of solvents in the adhesive solution are 10% by mass of ethyl acetate and 80% by mass of toluene, the adhesive tape 11 is prepared in the same manner as in Example 1.

[0099] (Comparative Example 4) The adhesive tape 12 was prepared in the same manner as in Example 1, except that the proportions of the solvents in the adhesive solution were 10% by mass of ethyl acetate and 80% by mass of methyl ethyl ketone.

[0100] (Comparative Example 5) The adhesive tape 13 was prepared in the same manner as in Example 1, except that the proportions of the solvents in the adhesive solution were 10% by mass of ethyl acetate and 80% by mass of n-hexane.

[0101] (Comparative Example 6) Except that the proportions of solvent in the adhesive solution are 10% by mass of ethyl acetate and 80% by mass of methyl acetate, the adhesive tape 14 is prepared in the same manner as in Example 1.

[0102] (Comparative Example 7) Except that the proportions of solvent in the adhesive solution are 10% by mass of ethyl acetate and 80% by mass of butyl acetate, the adhesive tape 15 is prepared in the same manner as in Example 1.

[0103] (Comparative Example 8) Except that the proportions of solvents in the adhesive solution are 10% by mass of ethyl acetate and 80% by mass of ethanol, the adhesive tape 16 was prepared in the same manner as in Example 1.

[0104] [evaluate] The double-sided adhesive tapes manufactured in the examples and comparative examples were evaluated according to the methods described below. The results of each evaluation are shown in Table 1 (Examples) and Table 2 (Comparative Examples). It should be noted that the values ​​in parentheses in the column for minimum adhesive strength are the ratios of the minimum value to the average value.

[0105] [Table 1]

[0106] [Table 2]

[0107] <Substrate thickness> Regarding the thickness of the aforementioned substrate, the thickness was measured in 0.1 μm units using a "Digimicro MF-501" manufactured by Nikon Corporation. The average thickness of the substrate was measured at 10 points along its width, and the average value was 2.0 μm.

[0108] <Thickness of adhesive layer> The thickness of the adhesive layer was measured using a "Digimicro MF-501" manufactured by Nikon Corporation. Specifically, the thickness (I) of the adhesive tape with the spacer (release layer) was measured. Then, the adhesive in the same area was wiped off with ethyl acetate, and the thickness (II) of that area was measured. Furthermore, the thickness of the adhesive layer was calculated as "thickness (I) - thickness (II)". The uniformity of the adhesive layer was evaluated by measuring 10 points along the width of the tape according to the following criteria. ◎: All 10 points (10 locations) are 1.5μm±0.2μm. 〇: All 10 points (10 locations) are 1.5μm±0.3μm. ×: Among the 10 points (10 locations), there is also 1 point (1 location) with a size smaller than 1.2μm or larger than 1.8μm.

[0109] <Environmental Response> Cut the double-sided adhesive tape to the specified size (area: 10cm²). 2 To make a sample, peel off the liner from one adhesive side of the sample and attach the aluminum foil to the adhesive side. Peel off the release liner covering the other adhesive side, leaving the adhesive side open, and place it into a 20 mL vial, then seal it with a stopper. The vial containing the sample was then heated at 80°C for 30 minutes. 1.0 mL of the heated gas was injected into a gas chromatograph (GC apparatus) using a headspace autosampler to determine the amounts of toluene and n-hexane. The measured values ​​of toluene or n-hexane were converted into the toluene content (emission amount) [ppm] or n-hexane content (emission amount) [ppm] per unit mass of adhesive in the sample (double-sided adhesive tape), and the environmental response was evaluated according to the following criteria. ◎: The detection limits for toluene and n-hexane are below 100 ppm. 〇: The detection limits for toluene and n-hexane are greater than 100 ppm and less than 1000 ppm. ×: The detection limits for toluene and n-hexane are greater than 1000 ppm.

[0110] The conditions for gas chromatography are as follows. • Column: DB-FFAP 1.0μm (diameter 0.535mm × 30m) • Carrier gas: He 5.0 mL / min • Column head pressure: 23 kPa (40℃) • Injection port: split (split ratio 12:1, temperature 250℃) • Column temperature: Increase the temperature from 40°C to 250°C at a rate of 10°C / min, and then hold at 250°C for 9 minutes. • Detector: FID (temperature 250℃)

[0111] <180-degree peel bond strength (uniformity of adhesive strength (matte PET)) on a matte layer surface with a maximum height (Rz) relative to the profile of 5.2 μm and an arithmetic mean roughness (Ra) of 0.5 μm in the adhesive tape> The surface of the matte layer is obtained by frosting one side of the Lumirror X30 (38μm) black polyester film manufactured by Toray Industries, Inc.

[0112] (1) A test board was prepared by fixing the non-frosted side (the other side) of a film made by frosting one side of a black polyester film Lumirror X30 (38μm) manufactured by Toray Industries, Inc. to an aluminum plate (0.5mm) using double-sided tape (DIC Corporation #8603TNW-10-4). (2) Cut the test sample (the adhesive tape of the present invention) into pieces with a width of 20 mm and a length of 100 mm relative to the flow direction (length direction) to make a test piece. Attach a 25 μm thick PET film to the opposite side of the test side of the double-sided tape. (3) In an atmosphere of 23℃ and 50% relative humidity, the test piece is subjected to one round-trip pressure at a speed of 300mm / min using a 2Kg rubber roller on the test plate. (4) For the test piece after the pressurization is completed, place it in an atmosphere of 23°C and 50% relative humidity for 5 minutes. (5) After the static period, place the test plate in one chuck of the tensile testing machine and clamp the clamping part of the test piece in another chuck. Then, peel it off from the test plate at a speed of 100 mm / min in a 180° direction under an atmosphere of 23°C and 50% relative humidity, and measure the adhesion force relative to the surface of the matte layer.

[0113] Regarding the uniformity of the above-mentioned adhesive strength (matte PET), the adhesive strength was measured at 10 points in the width direction and evaluated according to the following criteria. ◎: The minimum value is above 0.9N / 20mm, which is more than 60% of the average value. 〇: The minimum value is above 0.5N / 20mm, which is more than 40% of the average value. ×: Minimum value is less than 0.5N / 20mm.

[0114] <In adhesive tape, the offset distance (holding force) after 24 hours was measured when a shear holding force was applied under a 100g load at 100°C.>

[0115] Each double-sided adhesive tape was cut into 20mm widths, and the adhesive layer on one side was supported by a 50μm thick aluminum foil to serve as a test piece. The strips with the release lining removed from each double-sided adhesive tape were used as the test pieces. These test pieces were adhered to a clean, smooth stainless steel plate (SUS304) with an adhesion area of ​​20mm × 20mm. A 2kg roller was used to apply pressure to the upper surface, moving it back and forth once. The pressurized test pieces were then placed at 23°C and 50% relative humidity for 1 hour according to JIS Z-0237. Subsequently, a 100g load was applied in the shear direction at 100°C, and the tape offset distance of the test pieces was measured after 24 hours, and evaluated according to the following criteria. ◎: Offset distance less than 1mm 〇: Offset distance greater than 1mm and less than 2mm ×: Offset distance is 2mm or more

[0116] <180-degree peel bond strength relative to the SUS surface in the adhesive tape (uniformity of adhesive strength (SUS)> One side of each double-sided adhesive tape was adhered to a 25μm thick polyethylene terephthalate substrate, and the tape was cut into rectangles with a width of 20mm and a length of 100mm to make the adhesive tape used as the test sample. Next, at 23°C and 50% relative humidity, the adhesive tape was adhered to a stainless steel plate (SUS304), and a 2kg roller was used to roll back and forth once on the upper surface of the adhesive tape. The tape was then left to stand for 1 hour at 23°C and 50% relative humidity to produce a test piece made by pressing the adhesive tape and the stainless steel plate (SUS304). Next, using a Tensilon peel tester, with the stainless steel plate (SUS304) constituting the above test piece horizontally fixed, the above adhesive tape was peeled in a 180° direction at a peeling speed of 300 mm / min, and the strength at this time was measured.

[0117] Regarding the uniformity of the above-mentioned adhesion strength (SUS), the strength was measured at 10 points in the width direction and evaluated according to the following criteria. ◎: All 10 locations are within 5.0N / 20mm ± 1.5N / 20mm. 〇: All 10 locations are within 5.0N / 20mm ± 2.0N / 20mm. ×: At least one location does not fall within the range of 5.0N / 20mm±2.0N / 20mm.

[0118] Productivity Visually assess whether condensation occurs on the adhesive surface and release film during the production of each double-sided adhesive tape, and evaluate according to the following criteria. 〇: No condensation occurred. ×: Condensation occurs.

[0119] <The practicality of tape> Each double-sided adhesive tape is bonded to the 6μm of the electrolytic copper foil NC-WS manufactured by Furukawa Electric Industries, and the silicone protective film SI75-15 (adhesion force 0.02N / 25mm) manufactured by Nichiei Shinka is bonded to the aluminum foil. The product is then cut into 10mm×30mm pieces to produce the finished product. Subsequently, the processed product was adhered to the inside of the metal casing of the Apple iPhone 14 Pro and subjected to one pressurization using a 100g roller. After one minute, for 10 processed products, it was confirmed whether the double-sided tape bulged or peeled off from the metal casing when the protective film was peeled off at a speed of 5m / min, and the following criteria were used for evaluation. ◎: None of the 10 samples showed any signs of bulging or peeling. 〇: Creates 1 arch. ×: Creates more than 2 arches.

[0120] As can be seen from the results in Tables 1 and 2, the adhesive tape manufacturing method including the adhesive layer forming step described below can produce a thin adhesive tape with low toluene and n-hexane content but stable adhesive strength. In the adhesive layer forming step, an adhesive solution with an ethyl acetate content of 50% to 95% by mass, a toluene content of 1% to 1% by mass, a n-hexane content of 1% to 1% by mass, and a solid component concentration of 5% to 20% by mass is prepared on the surface of the substrate to form an adhesive layer with a thickness of 0.5 μm to 5 μm.

[0121] Examples of embodiments of the present invention include the following. <1> A method for manufacturing an adhesive tape, characterized in that it includes an adhesive layer forming step, wherein an adhesive solution having an ethyl acetate content of 50% to 95% by mass, a toluene content of 1% to 1% by mass, a n-hexane content of 1% to 1% by mass, and a solid component concentration of 5% to 20% by mass is disposed on the surface of a substrate to form an adhesive layer with a thickness of 0.5 μm to 5 μm. <2> According to the above <1> The method for manufacturing the adhesive tape, wherein in the adhesive layer forming step, the adhesive layer is formed such that the thickness tolerance of the adhesive layer is ±0.3 μm. <3> According to the above <1> The method for manufacturing the adhesive tape, wherein in the adhesive layer forming process, a microgravure coating machine, a small-diameter gravure coating machine, or a die coating machine is used to form the adhesive layer. <4> According to the above <1> In the method for manufacturing the adhesive tape, the content of the hydroxyl compound in the adhesive solution is less than 1% by mass. <5> According to the above <4> In the method for manufacturing the adhesive tape, the compound having a hydroxyl group is an alcohol. <6> According to the above <1> The method for manufacturing the adhesive tape, wherein the adhesive solution contains an acrylic adhesive. <7> According to the above <1> The method for manufacturing the adhesive tape, wherein the adhesive solution contains an isocyanate crosslinking agent. <8> According to the above <1> The method for manufacturing the adhesive tape, wherein the adhesive solution contains a tackifying resin. <9> An adhesive tape, characterized in that, It has a substrate and an adhesive layer on at least one of the substrates. The thickness of the aforementioned adhesive layer is 0.2 μm or more and 5.3 μm or less. The toluene content in the aforementioned adhesive layer is below 1000 ppm. The hexane content of the aforementioned adhesive layer is below 1000 ppm. The minimum value of the 180-degree peel adhesion force of the matte layer surface with a maximum profile height (Rz) of 5.2 μm and an arithmetic mean roughness (Ra) of 0.5 μm in the above adhesive tape is 0.5 N / 20 mm or more when measured 10 times, and the minimum value of the above 10 measurements is more than 0.4 times the average value of the above 10 measurements. <10> According to the above <9> The adhesive tape, wherein the adhesive layer contains an acrylic adhesive. <11> According to the above <9> The adhesive tape wherein the adhesive layer has a cross-linked structure derived from an isocyanate cross-linking agent. <12> According to the above <9> The adhesive tape, wherein the adhesive layer contains a tackifying resin. <13> According to the above <9> The adhesive tape, wherein when the shear holding force is measured by applying a load of 100g at 100°C, the offset distance after 24 hours is less than 1mm. <14> According to the above <9> The adhesive tape, wherein the 180-degree peel bond strength relative to the SUS surface is 3.5 N / 20 mm or more and 20.0 N / 20 mm or less.

Claims

1. A method for manufacturing an adhesive tape, characterized in that, It includes an adhesive layer forming process, in which an adhesive solution containing ethyl acetate of 50% to 95% by mass, toluene of 1% to 1% by mass, n-hexane of 1% to 1% by mass, and a solid component concentration of 5% to 20% by mass is applied to the surface of a substrate to form an adhesive layer with a thickness of 0.5 μm to 5 μm.

2. The method for manufacturing adhesive tape according to claim 1, wherein, In the adhesive layer forming process, the adhesive layer is formed such that the thickness tolerance of the adhesive layer is ±0.3 μm.

3. The method for manufacturing adhesive tape according to claim 1, wherein, In the adhesive layer forming process, a microgravure coating machine, a small-diameter gravure coating machine, or a die coating machine is used to form the adhesive layer.

4. The method for manufacturing adhesive tape according to claim 1, wherein, The content of the hydroxyl-containing compound in the adhesive solution is less than 1% by mass.

5. The method for manufacturing adhesive tape according to claim 4, wherein, The compound containing a hydroxyl group is an alcohol.

6. The method for manufacturing adhesive tape according to claim 1, wherein, The adhesive solution contains an acrylic adhesive.

7. The method for manufacturing adhesive tape according to claim 1, wherein, The adhesive solution contains an isocyanate crosslinking agent.

8. The method for manufacturing adhesive tape according to claim 1, wherein, The adhesive solution contains a tackifying resin.

9. An adhesive tape, characterized in that, It has a substrate and an adhesive layer disposed on at least one of the substrates. The thickness of the adhesive layer is greater than 0.2 μm and less than 5.3 μm. The toluene content in the adhesive layer is below 1000 ppm. The hexane content of the adhesive layer is below 1000 ppm. The minimum value of the 180-degree peel adhesion force of the matte layer surface with a maximum profile height (Rz) of 5.2 μm and an arithmetic mean roughness (Ra) of 0.5 μm in the adhesive tape is 0.5 N / 20 mm or more when measured 10 times, and the minimum value of the 10 measurements is more than 0.4 times the average value of the 10 measurements.

10. The adhesive tape according to claim 9, wherein, The adhesive layer contains an acrylic adhesive.

11. The adhesive tape according to claim 9, wherein, The adhesive layer has a cross-linked structure derived from the isocyanate cross-linking agent.

12. The adhesive tape according to claim 9, wherein, The adhesive layer contains a tackifying resin.

13. The adhesive tape according to claim 9, wherein, When the shear holding force of the adhesive tape was measured under a load of 100g at 100°C, the offset distance after 24 hours was less than 1mm.

14. The adhesive tape according to claim 9, wherein, The adhesive tape has a 180-degree peel bond strength relative to the SUS surface of 3.5 N / 20 mm or more and 20.0 N / 20 mm or less.

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