Adhesive tape and method for manufacturing the same

Abstract

To provide a thin adhesive tape with stable adhesive strength, despite having low toluene and n-hexane content. [Solution] The adhesive tape comprises a base material and an adhesive layer on at least one side of the base material, 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 when measuring the 180-degree peel adhesion force of the adhesive tape against a mat layer surface with a maximum height roughness (Rz) of 5.2 μm and an arithmetic mean roughness (Ra) of 0.5 μm 10 times is 0.5 N / 20 mm or more, and the minimum value when measuring 10 times is 0.4 times or more the average value when measuring 10 times.

Description

Technical Field

[0001] The present invention relates to an adhesive tape and a method for manufacturing the same.

Background Art

[0002] When fixing components that make up articles such as electronic devices, adhesive tapes are widely used.

[0003] Particularly in recent years, in the above-mentioned electronic devices such as portable electronic terminals such as personal computers, digital video cameras, electronic notebooks, mobile phones, PHS, smartphones, game devices, and e-books, high functionality and thinning have been strongly demanded. Therefore, in the manufacturing scene of the portable electronic terminal, along with the thinning of the main components, further thinning is also required for the adhesive tape used for fixing these components.

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

[0005] In order to obtain a stable adhesive force, it is required to make the thickness of the adhesive layer uniform. As solvents that can be uniformly applied with a uniform thickness, toluene and n-hexane are known, but these solvents are known to have an environmental impact and an impact on the human body, and it is desirable to suppress their inclusion in the product. Therefore, although the content rates of toluene and n-hexane are low, there is a strong demand for promptly providing a thin adhesive tape having a stable adhesive force.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

[0007] The present invention aims to solve the aforementioned problems in the conventional era and achieve the following objectives. Specifically, the present invention aims to provide a thin adhesive tape that has a low content of toluene and n-hexane but possesses stable adhesive strength. [Means for solving the problem]

[0008] As a result of diligent research conducted by the inventors to achieve the above objective, they have found that it is possible to provide a thin adhesive tape with stable adhesive strength despite having low toluene and n-hexane content.

[0009] The present invention is based on the aforementioned findings by the inventors, and the means for solving the aforementioned problems are as follows: <1> The method for manufacturing adhesive tape is characterized by including an adhesive layer formation step, in which an adhesive solution having an ethyl acetate content of 50% to 95% by mass, a toluene content of 1% by mass or less, an n-hexane content of 1% by mass or less, and a solid content 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 substrate comprises an adhesive layer on at least one side of the substrate, 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. The adhesive tape is characterized in that, when the 180-degree peel adhesive strength of the adhesive tape is measured 10 times on a mat layer surface with a maximum height roughness (Rz) of 5.2 μm and an arithmetic mean roughness (Ra) of 0.5 μm, the minimum value is 0.5 N / 20 mm or more, and the minimum value when measured 10 times is 0.4 times or more the average value when measured 10 times. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a thin adhesive tape that has a low content of toluene and n-hexane, but possesses stable adhesive strength. [Modes for carrying out the invention]

[0011] (Adhesive tape) The adhesive tape comprises a base material and an adhesive layer, and may further have other layers. The adhesive layer may be provided on at least one of the substrates, or on both surfaces of the substrate.

[0012] <Base material> The substrate can support the adhesive layer.

[0013] The aforementioned substrate is not particularly limited and can be appropriately selected depending on the purpose, but a resin film is preferred. The aforementioned resin is not particularly limited and can be appropriately selected depending on the purpose, but examples include polyesters such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polybutylene terephthalate (PBT), amide resins such as polyamide (nylon) and fully aromatic polyamide (aramid), polyacrylate resins such as polybutyl acrylate and polyethyl acrylate, methacrylate resins such as methyl methacrylate (PMMA), polystyrene, acrylonitrile-styrene copolymer (AS resin), and acrylonitrile-butadiene-styrene copolymer. Examples include styrene resins such as ABS resin, polyether ether ketones such as polyether ether ketone (PEEK) and polyether ketone ketone, polyether sulfone (PES), polysulfone, polyvinyl chloride (PVC), polyphenylene sulfide (PPS), polyimide (PI), polyamide imide, polyetherimide (PEI), polyester imide, polycarbonate (PC), polyacetal, polyarylene ether (such as polyphenylene ether), polyphenylene sulfide, polyarylate, polyaryl, polyurethanes, and epoxy resins. These resins may be used individually or in combination of two or more. Among these, polyester is preferred in terms of thickness accuracy, economy (cost), tensile strength, and processability, and polyethylene terephthalate is more preferred.

[0014] There are no particular restrictions on the resin film, and it can be appropriately selected depending on the purpose, but a biaxially oriented film is preferred. Biaxial orienteding allows for the development of high strength.

[0015] There are no particular restrictions on the average thickness of the substrate, and it can be appropriately selected depending on the purpose, but it is preferably 0.5 μm to 100 μm, more preferably 1.0 μm to 12 μm, and even more preferably 1.5 μm to 2.5 μm.

[0016] The thickness of the aforementioned substrate is measured in units of 0.1 μm using a Nikon Corporation "DigiMicro MF-501". The average thickness of the base material is the average value obtained by measuring the base material at 10 points in the width direction.

[0017] Commercially available products can be used as the base material. Examples of commercially available products of the base material include, for example, Lumirror 2F51 (2.0 μm) manufactured by Toray Industries, Inc., K750 (2.0 μm) manufactured by Mitsubishi Chemical Corporation, and the like.

[0018] <Adhesive layer> The adhesive layer is provided on at least one of the base materials. That is, the adhesive layer may be provided on one of the base materials, or may be provided on both surfaces of the base materials. The adhesive layer may be provided directly in contact with one or both surfaces of the base material, or may be provided with another layer interposed therebetween.

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

[0020] -Adhesive- There is no particular limitation on the adhesive, and it can be appropriately selected according to the purpose. For example, 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, fluorine adhesives, creep property-improved adhesives, radiation-curable adhesives, etc. can be used. Among these, acrylic adhesives are preferred because of their excellent adhesion reliability.

[0021] Examples of the acrylic adhesive include those containing an acrylic polymer. Examples of the acrylic polymer include those obtained by polymerizing a monomer component containing (meth)acrylic monomers such as (meth)acrylic acid alkyl esters.

[0022] Examples of the alkyl (meth)acrylate esters include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and methyl (meth)acrylate. Examples include isooctyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, octadecyl (meth)acrylate, nonadecyl (meth)acrylate, and eicosyl (meth)acrylate. The alkyl (meth)acrylate esters may be used individually or in combination of two or more. Among these, the alkyl (meth)acrylate ester is preferably one in which the alkyl group has 1 to 20 carbon atoms, more preferably one in which the alkyl group has 4 to 18 carbon atoms, and even more preferably one in which the alkyl group has 4 to 9 carbon atoms. The alkyl group can be a linear or branched alkyl group. In this specification, "(meth)acrylate alkyl ester" means alkyl acrylate or alkyl methacrylate.

[0023] Among these, butyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isononyl (meth)acrylate, and ethyl (meth)acrylate are preferred as alkyl (meth)acrylate esters because they easily ensure suitable adhesive strength.

[0024] The alkyl (meth)acrylate is preferably used in an amount of 90% to 99% by mass relative to the total amount of the (meth)acrylic monomer, and more preferably in an amount of 90% to 96% by mass, as this makes it easier to ensure sufficient adhesion.

[0025] In addition to alkyl (meth)acrylate esters, the (meth)acrylic monomer may also be a monomer having a polar group such as a hydroxyl group, a carboxyl group, or an amide group. Specifically, monomers having a carboxyl group, such as (meth)acrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid, or their anhydrides; monomers having a sulfonic acid group, such as sodium vinylsulfonate; monomers having a cyano group, such as acrylonitrile; monomers having an amide group, such as acrylamide, methacrylamide, N-vinylpyrrolidone, N,N-dimethyl(meth)acrylamide; monomers having a hydroxyl group, such as hydroxyalkyl (meth)acrylate and glycerin dimethacrylate; monomers having an amino group, such as aminoethyl (meth)acrylate and (meth)acryloylmorpholine; monomers having an imide group, such as cyclohexylmaleimide and isopropylmaleimide. Examples of monomers include: monomers having epoxy groups such as glycidyl (meth)acrylate and methylglycidyl (meth)acrylate; monomers having isocyanate groups such as 2-methacryloyloxyethyl isocyanate; 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 may be used individually or in combination of two or more.

[0026] In addition to (meth)acrylic 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 the monomer.

[0027] The aforementioned acrylic polymer can be produced by polymerizing monomers using methods such as solution polymerization, bulk polymerization, suspension polymerization, and emulsion polymerization, but solution polymerization is preferred because it improves the production efficiency of the acrylic polymer.

[0028] The aforementioned solution polymerization method is not particularly limited and can be appropriately selected depending on the purpose. For example, a method can be used in which a monomer, a polymerization initiator, and an organic solvent are mixed and stirred at a temperature of 40°C to 90°C to carry out radical polymerization.

[0029] There are no particular restrictions on the polymerization initiator, and it can be appropriately selected depending on the purpose. Examples include peroxides such as benzoyl peroxide and lauryl peroxide, azo-based thermal polymerization initiators such as azobisisobutylnitrile, 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. The acrylic polymer obtained by the above method may be dissolved or dispersed in an organic solvent, for example, if it is produced by solution polymerization.

[0030] The acrylic polymer obtained by the above method is preferably one having a weight-average molecular weight of 300,000 to 1,200,000, more preferably one having a weight-average molecular weight of 400,000 to 1,100,000, and even more preferably one having a weight-average molecular weight of 500,000 to 1,000,000, in order to have excellent adhesive strength even in thin layers.

[0031] The aforementioned weight-average molecular weight is measured by gel permeation chromatography (GPC) and refers to the value calculated by converting it to standard polystyrene. Specifically, the weight-average molecular weight is measured using a GPC device (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: 1.0mL / min Measurement temperature: 40℃ This column: TSKgel GMHHR-H (20) x 2 Guard column: TSKgel HXL-H Detector: Differential refractometer Weight-average molecular weight of standard polystyrene: 10,000 to 20,000,000 (manufactured by Tosoh Corporation)

[0032] -Other components in the adhesive layer- Other components in the adhesive layer are not particularly limited and can be appropriately selected depending on the purpose. Examples include tackifying resins, colorants, crosslinking agents (solidifying agents), softeners, plasticizers, fillers, antioxidants, and residual solvents.

[0033] The adhesive layer preferably contains a tackifying resin in order to provide stable adhesive strength.

[0034] There are no particular restrictions on the tackifying resin, and it 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] As the tackifying resin, it is preferable to use a combination of rosin-based tackifying resins and petroleum resin-based tackifying resins, as they provide excellent adhesive strength even in thin layers. The rosin-based tackifying resin and the petroleum resin-based tackifying resin are particularly preferred to be used in combination with the acrylic polymer, and more preferably in combination with the acrylic polymer obtained by polymerizing a monomer containing (meth)butyl acrylate, in order to obtain even better adhesive strength even in thin layers.

[0036] As the tackifying resin, it is preferable to use a tackifying resin that is liquid at room temperature, in order to further improve the initial adhesive strength of the adhesive layer. The aforementioned liquid tackifying resin at room temperature is not particularly limited and can be appropriately selected depending on the purpose. Examples include process oil, polyester plasticizers, low molecular weight liquid rubber such as polybutene, and terpene phenol resins. A commercially available example is YP-90L manufactured by Yasuhara Chemical Co., Ltd.

[0037] The tackifying resin is preferably used in an amount of 20 to 60 parts by mass, and more preferably in an amount of 30 to 55 parts by mass, per 100 parts by mass of the adhesive, in order to provide even better adhesive strength.

[0038] There are no particular restrictions on the coloring agent, and it can be appropriately selected depending on the purpose. Examples include pigments.

[0039] There are no particular restrictions on the crosslinking agent, and it can be appropriately selected depending on the purpose. However, in terms of providing stable adhesive strength, isocyanate crosslinking agents or epoxy crosslinking agents are preferred, and isocyanate crosslinking agents are more preferred. In other words, in terms of providing stable adhesive strength, it is preferable that the adhesive layer has a crosslinked structure derived from an isocyanate crosslinking agent or an epoxy crosslinking agent, and more preferably that it has a crosslinked structure derived from an isocyanate crosslinking agent.

[0040] There are no particular restrictions on the isocyanate crosslinking agent, and it can be appropriately selected depending on the purpose. For example, tolylene diisocyanate, naphthylene-1,5-diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, trimethylolpropane-modified tolylene diisocyanate, etc., can be used, and toluene diisocyanate adducts such as tolylene diisocyanate and trimethylolpropane-modified tolylene diisocyanate are preferred. The toluene diisocyanate adduct is one that has a structure derived from toluene diisocyanate in its molecule, and a commercially available example is Coronate L (manufactured by Nippon Polyurethane Industry Co., Ltd.).

[0041] When using the isocyanate crosslinking agent, it is preferable to use an acrylic polymer having hydroxyl groups as the acrylic polymer. The acrylic polymer having a hydroxyl group can be manufactured using monomers such as 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and 6-hydroxyhexyl (meth)acrylate, and among these, 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate are more preferable.

[0042] There are no particular restrictions on the epoxy crosslinking agent, and it can be appropriately selected depending on the purpose. Examples include Tetrad X and Tetrad C manufactured by Mitsubishi Gas Chemical Corporation, or E-05X manufactured by Soken Chemical Co., Ltd.

[0043] When using the epoxy crosslinking agent, it is preferable to use an acrylic polymer having acid groups as the acrylic polymer. The acrylic polymer having the acid group may preferably use, for example, (meth)acrylic acid, acrylate dimer, itaconic acid, crotonic acid, maleic acid, maleic anhydride, etc., as monomers used in its production, and it is more preferable to use (meth)acrylic acid.

[0044] There are no particular restrictions on the content of the crosslinking agent in the adhesive layer, and it can be appropriately selected depending on the purpose, but 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, per 100 parts by mass of adhesive solids.

[0045] Examples of the residual solvent include solvents used in the adhesive solution (coating liquid) in the adhesive layer, such as ethyl acetate, toluene, and n-hexane. However, in the present invention, since toluene and n-hexane are not substantially used as the solvent, the content in the adhesive layer is as follows.

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

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

[0048] In a double-sided adhesive tape, the content of toluene in the adhesive layer and the content of n-hexane in the adhesive layer are measured by the following method. Double-sided adhesive tape to a specified size (area: 10cm²) 2 Cut out a sample from the material and peel off the release liner from one side of the sample, then attach the aluminum foil to the adhesive surface. Remove the release liner covering the other adhesive surface to expose it, then place it in a 20 mL vial and seal it tightly. Subsequently, the vial containing the sample is heated at 80°C for 30 minutes, and 1.0 mL of the heated gas is injected into a gas chromatograph (GC) measuring device using a headspace autosampler to measure the amounts of toluene and n-hexane. The measured values ​​of toluene or n-hexane are converted to 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). Note that for single-sided adhesive tape, the measurement should be taken without attaching aluminum foil to the adhesive surface.

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

[0050] The thickness of the adhesive layer is not particularly limited as long as it is between 0.2 μm and 5.3 μm, and can be appropriately selected according to the purpose. However, in terms of providing stable adhesive strength, a thickness of 0.5 μm to 5.0 μm is preferred, 1.2 μm to 4.0 μm is more preferred, 1.5 μm to 3.0 μm is even more preferred, 1.7 μm to 3.0 μm is particularly preferred, and 2.0 μm to 3.0 μm is most preferred.

[0051] There are no particular restrictions on the average thickness of the adhesive layer, and it can be appropriately selected depending on the purpose. However, in terms of providing stable adhesive strength, a thickness of 1.0 μm to 5.0 μm is preferred, 1.5 μm to 4.0 μm is more preferred, and 2.0 μm to 3.5 μm is even more preferred.

[0052] The thickness of the adhesive layer is measured in units of 0.1 μm using a Nikon Corporation "DigiMicro MF-501". First, measure the thickness (I) of the adhesive tape with a separator (release layer). Next, scrape off only the adhesive at the same location with ethyl acetate and measure the thickness (II) at that location. Then, calculate the thickness of the adhesive layer by subtracting the difference between "thickness (I)" and "thickness (II)". The average thickness of the substrate is the average value obtained by measuring the substrate at 10 points in the width direction.

[0053] <Other layers> The aforementioned other layers are not particularly limited and can be appropriately selected according to the purpose. Examples include release layers, resin layers, light-shielding layers, light-reflecting layers, conductive layers, heat-conducting layers, and electromagnetic wave shielding layers. There are no particular restrictions on the position of the other layers in the adhesive tape, and they can be appropriately selected according to the purpose.

[0054] -Exfoliation layer- The release layer can be provided on the side of the adhesive layer opposite to the substrate. The release layer may be provided in direct contact with the side of the adhesive layer opposite to the substrate, or it may be provided with another layer in between.

[0055] There are no particular restrictions on the release layer, and it can be appropriately selected depending on the purpose. Examples include papers such as kraft paper, glassine paper, and fine paper; resin films such as polyethylene, polypropylene (OPP, CPP), and polyethylene terephthalate; laminated paper made by laminating the papers and resin films; and papers that have been treated with a sealant such as clay or polyvinyl alcohol, and then treated with a release agent such as a silicone resin on one or both sides. Among these, a film made of biaxially oriented polyethylene terephthalate is preferred because it offers excellent thickness uniformity, allowing for a consistent thickness of the adhesive tape.

[0056] There are no particular restrictions on the average thickness of the release layer, and it can be appropriately selected depending on the purpose, but it is preferably 6 μm to 100 μm, more preferably 12 μm to 75 μm, even more preferably 16 μm to 50 μm, particularly preferably 23 μm to 38 μm, and most preferably 23 μm to 26 μm. Using a thin release layer makes it easier to control the thickness of the adhesive. If it is too thin, wrinkles are likely to occur during adhesive coating.

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

[0058] The minimum value of the 180-degree peel adhesive strength of the aforementioned adhesive tape when measured 10 times on a mat layer surface with a maximum height roughness (Rz) of 5.2 μm and an arithmetic mean roughness (Ra) of 0.5 μm is 0.5 N / 20 mm or more. As long as the minimum value when measured 10 times is 0.4 times or more the average value when measured 10 times, there are no particular restrictions, and it can be appropriately selected according to the purpose.

[0059] In the aforementioned adhesive tape, the minimum value when measuring the 180-degree peel adhesion force 10 times on the surface of a mat layer with a maximum height roughness (Rz) of 5.2 μm and an arithmetic mean roughness (Ra) is preferably 0.5 N / 20 mm or more, more preferably 0.8 N / 20 mm or more, even more 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] In the case of the adhesive tape described above, the minimum value of the 180-degree peel adhesive strength to the surface of a mat layer with a maximum height roughness (Rz) of 5.2 μm and an arithmetic mean roughness (Ra) of 0.5 μm, measured 10 times, is preferably 0.5 times or more, and more preferably 0.6 times or more, the average value of the 10 measurements.

[0061] The 180-degree peel adhesion strength of the aforementioned adhesive tape to a matte layer surface with a maximum height roughness (Rz) of 5.2 μm and an arithmetic mean roughness (Ra) of 0.5 μm is measured by the following method. The surface of the aforementioned matte layer is made by sand-matting one side of Lumirror X30 (38 μm), a black polyester film manufactured by Toray Industries, Inc.

[0062] (1) Prepare a test plate by fixing the non-sand-matted side (other side) of a Toray Industries, Inc. black polyester film Lumirror X30 (38 μm) that has been sand-matted on one side, to an aluminum plate (0.5 mm) with double-sided tape (DIC Corporation #8603TNW-10-4). (2) Prepare a test piece by cutting the sample for measurement (adhesive tape of the present invention) to a width of 20 mm and a length of 100 mm in the flow direction (length direction). In the case of double-sided tape, attach a PET film with a thickness of 25 μm to the opposite side of the measurement surface. (3) In an atmosphere of 23°C and 50% relative humidity, the test specimen is pressed onto the test plate using a 2 kg rubber roller at a speed of 300 mm / min for one back-and-forth motion. (4) After pressurization is complete, leave the test specimen in an atmosphere of 23°C and 50% relative humidity for 5 minutes. (5) After the standing period is complete, the test plate is set in one chuck of the tensile testing machine, and the gripping portion of the test piece is clamped in the other chuck. Subsequently, the test piece is peeled off 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 the adhesive strength to the surface of the mat layer is measured.

[0063] The maximum height roughness (Rz) and arithmetic mean roughness (Ra) of the mat layer surface are measured in accordance with JIS B0601:2013, using a 3D color laser scanning microscope (OLS4100, manufactured by Olympus Corporation) as the test apparatus, under conditions of 23±2℃ and 50±10% relative humidity, with a microscope magnification of 1000x and a threshold λC of 800μm. The maximum height roughness (Rz) and arithmetic mean roughness (Ra) of the mat layer surface are determined by taking surface measurements at three arbitrary locations (each measuring 8 cm vertically and 8 cm horizontally) on the mat layer surface, and taking the average of the three measured points as the maximum height roughness (Rz) and arithmetic mean roughness (Ra) of the mat layer surface.

[0064] In the aforementioned adhesive tape, there are no particular restrictions on the displacement distance after 24 hours when the shear holding force is measured under a load of 100g in a 100°C environment, and it can be appropriately selected according to the purpose. However, in terms of providing stable adhesive strength, it is preferable to have a displacement of less than 2mm, more preferably 1mm or less, even more preferably less than 1mm, particularly preferably 0.5mm or less, and most preferably 0.1mm or less.

[0065] The shear holding force of the aforementioned adhesive tape, measured under a 100g load in a 100°C environment, is determined by the following method after 24 hours. A test specimen was prepared by cutting an adhesive tape to a width of 20 mm and backing one side of the adhesive layer with 50 μm thick aluminum foil. The release liner of the adhesive tape was removed to prepare the test specimen, which was then attached to the surface of a clean, smooth stainless steel plate (SUS304) to create a 20 mm x 20 mm application area. Pressure was applied to the top surface by using a 2 kg roller to pass it back and forth once, and the specimen was left for 1 hour under conditions of 23°C and 50% relative humidity, in accordance with JIS Z-0237. After that, a 100 g load was applied in the shear direction under an atmosphere of 100°C, and the displacement distance of the tape on the test specimen after 24 hours was measured.

[0066] The 180-degree peel adhesive strength of the adhesive tape to the SUS surface is not particularly limited and can be appropriately selected depending on the purpose. However, in terms of providing stable adhesive strength, 3.0 N / 20 mm to 20.0 N / 20 mm is preferred, 3.5 N / 20 mm to 20.0 N / 20 mm is more preferred, 4.0 N / 20 mm to 10.0 N / 20 mm is even more preferred, and 4.5 N / 20 mm to 8.0 N / 20 mm is particularly preferred.

[0067] The 180-degree peel adhesion strength of the aforementioned adhesive tape to the SUS surface is measured by the following method. A sample of adhesive tape for measurement is created by attaching one side of double-sided adhesive tape to a polyethylene terephthalate substrate with a thickness of 25 μm and cutting it into a rectangle measuring 20 mm wide x 100 mm long. For single-sided tape, the step of attaching it to the polyethylene terephthalate substrate is omitted. Next, in an environment of 23°C and 50% relative humidity, the adhesive tape is attached to a stainless steel plate (SUS304), a 2kg roller is used to move the top surface of the adhesive tape back and forth once, and then the two are left to stand for 1 hour in an environment of 23°C and 50% relative humidity to create a test piece in which the adhesive tape and the stainless steel plate (SUS304) are pressed together. Next, using a Tensilon peel tester, the strength of the adhesive tape is measured when it is peeled off in a 180° direction at a peeling speed of 300 mm / min while the stainless steel plate (SUS304) constituting the test piece is fixed horizontally.

[0068] The aforementioned adhesive tape can be manufactured by the method described later (Method for manufacturing adhesive tape).

[0069] (Method of manufacturing adhesive tape) The method for manufacturing the adhesive tape includes an adhesive layer forming step, and may further include other steps.

[0070] -Adhesive layer formation process- The adhesive layer formation step involves applying an adhesive solution to the surface of a substrate so that the thickness is between 0.5 μm and 5 μm to form an adhesive layer.

[0071] The adhesive solution may be applied to the substrate and then placed on the substrate, or it may be applied to the release layer and then placed on the substrate. In other words, an adhesive solution can be applied to a substrate or release layer to form an adhesive layer with a thickness of 0.5 μm or more and 5 μm or less. The aforementioned base material is as described in the <Base Material> section of the (adhesive tape) above. The aforementioned release layer is as described in "-Release Layer-" of the <Other Layers> of the (Adhesive Tape) above.

[0072] In the adhesive layer formation step, it is preferable to form the adhesive layer such that the tolerance of the thickness of the adhesive layer is ±0.3 μm, and more preferable to form the adhesive layer such that the tolerance of the thickness of the adhesive layer is ±0.2 μm, in order to make the thickness of the adhesive layer uniform and provide stable adhesive strength.

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

[0074] The solvent is not particularly limited as long as it has a boiling point of 57°C or higher and 125°C or lower, and can be appropriately selected according to the purpose. For example, alkyl acetate, specifically ethyl acetate, which has a boiling point of 57°C or higher and 125°C or lower, is preferred. Among the alkyl acetates mentioned above, methyl acetate has a boiling point of 56.9°C, ethyl acetate has a boiling point of 77.1°C, and butyl acetate has a boiling point of 126°C. Therefore, ethyl acetate is the solvent with a boiling point between 57°C and 125°C.

[0075] If the boiling point of the solvent is too low, the solid content concentration of the adhesive will change during coating, which will also change the thickness of the adhesive layer. Furthermore, the heat of vaporization during solvent evaporation causes condensation of water in the adhesive, resulting in water absorption (brushing). This water then reacts with the crosslinking agent (such as isocyanate), preventing the desired degree of crosslinking from being achieved and reducing the adhesive properties. Furthermore, if the boiling point is too high, drying will be insufficient, increasing the amount of residual solvent and reducing the adhesive properties.

[0076] The ethyl acetate content in the adhesive solution is not particularly limited as long as it is between 50% by mass and 95% by mass, and can be appropriately selected depending on the purpose, but 55% by mass and 95% by mass is preferred, 60% by mass and 95% by mass is more preferred, and 70% by mass and 95% by mass is even more preferred.

[0077] The toluene content in the adhesive solution is not particularly limited as long as it is 1% by mass or less, and can be appropriately selected depending on the purpose, but 0.5% by mass or less is preferred, 0.1% by mass or less is more preferred, and below the detection limit is even more preferred.

[0078] The n-hexane content in the adhesive solution is not particularly limited as long as it is 1% by mass or less, and can be appropriately selected depending on the purpose, but 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 compound having a hydroxyl group in the adhesive solution is not particularly limited and can be appropriately selected depending on the purpose, but it is preferably 1% by mass or less, more preferably 0.5% by mass or less, even more preferably 0.1% by mass or less, and particularly preferably below the detection limit.

[0080] The compound having the hydroxyl group is not particularly limited and can be appropriately selected depending on the purpose. Examples include alcohols such as ethanol.

[0081] The solid content concentration of the adhesive solution is not particularly limited as long as it is between 5% by mass and 20% by mass, and can be appropriately selected according to the purpose. However, in terms of providing stable adhesive strength, 7% by mass and 15% by mass is preferred, 8% by mass and 13% by mass is more preferred, and 9% by mass and 12% is even more preferred.

[0082] -Other components in the adhesive solution- Other components in the adhesive solution are not particularly limited and can be appropriately selected depending on the purpose. Examples include tackifying resins, colorants, crosslinking agents (solidifying agents), softeners, plasticizers, fillers, and antioxidants. The tackifying resin is as described in the <adhesive layer> of the (adhesive tape) above. The aforementioned coloring agent is as described in the <adhesive layer> of the (adhesive tape) above. The crosslinking agent is as described in the <adhesive layer> section of the (adhesive tape) above.

[0083] The adhesive layer can be formed by known coating methods, such as microgravure coaters, small-diameter gravure coaters, die coaters, and comma coaters. Among these methods, it is preferable to use a microgravure coater, a small-diameter gravure coater, or a die coater for formation, as this provides stable adhesive strength.

[0084] The aforementioned microgravure coater or small-diameter gravure coater refers to a gravure roll with a diameter of φ20 mm or more and less than 300 mm. In the aforementioned microgravure coater or small-diameter gravure coater, the cell volume of the gravure roll is 50 cm², in terms of providing stable adhesive strength. 3 / m 2 More than 100cm 3 / m 2 The following are preferable. [Examples]

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

[0086] [Preparation of adhesive] <Adhesive A> An acrylic polymer with a weight-average molecular weight of 900,000 was obtained by solution polymerization of 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, with 0.2 parts by mass of azobisisobutyronitrile as a polymerization initiator, in an ethyl acetate solution at 77°C for 8 hours. A tack solution was obtained by mixing 100 parts by mass of the acrylic polymer with 5 parts by mass of "D-135" (manufactured by Arakawa Chemical Industries, Ltd., polymerized rosin ester), 20 parts by mass of "KE-100" (manufactured by Arakawa Chemical Industries, Ltd., disproportionate rosin ester), and 25 parts by mass of "FTR6100" (manufactured by Mitsui Chemicals, Inc., petroleum resin), and then adding ethyl acetate to adjust the solid content to 50% by mass. Adhesive A was obtained by mixing the aforementioned adhesive solution with 1.1 parts by mass of "NC40" (manufactured by DIC Corporation, isocyanate crosslinking agent) and stirring.

[0087] <Adhesive B> An acrylic polymer with a weight-average molecular weight of 900,000 was obtained by solution polymerization of 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, with 0.2 parts by mass of azobisisobutyronitrile as a polymerization initiator, in an ethyl acetate solution at 77°C for 8 hours. To 100 parts by mass of the aforementioned acrylic polymer, 15 parts by mass of "D-135" (manufactured by Arakawa Chemical Industries, Ltd., polymerized rosin ester) and 35 parts by mass of "KE-100" (manufactured by Arakawa Chemical Industries, Ltd., disproportionated rosin ester) were mixed, and ethyl acetate was added to obtain an adhesive solution adjusted to a solid content concentration of 50% by mass. Adhesive B was obtained by mixing the aforementioned adhesive solution with 1.4 parts by mass of "NC40" (manufactured by DIC Corporation, isocyanate crosslinking agent) and stirring.

[0088] [Manufacturing of adhesive tape] (Example 1) The adhesive tape was made using the following procedure. An adhesive solution was prepared by adding ethyl acetate to adhesive A and stirring to adjust it to a concentration of 90% by mass of ethyl acetate and 10% by mass of solids. This solution was applied to a release film at a speed of 40 m / min using a microgravure coater, and the coated laminate was sequentially transported and passed through seven drying zones for drying. After drying, it was bonded to 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 applied to a release film in the same manner, and after drying, it was bonded to 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 drying zones were 7 zones × 3m each, and the temperatures of the drying zones were 60°C, 70°C, 80°C, 90°C, 100°C, 90°C, and 80°C, respectively, from the first to the seventh drying zone. The average thickness of the adhesive layer was 1.5 μm. The average thickness was calculated by taking measurements at 10 points along the width of the tape.

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

[0090] (Example 3) Adhesive tape 3 was prepared in the same manner as in Example 1, except that the solid content concentration of the adhesive solution was changed from 10% by mass to 15% by mass.

[0091] (Example 4) Adhesive tape 4 was prepared in the same manner as in Example 1, except that the ratio of solvents in the adhesive solution was 60% by mass of ethyl acetate and 30% by mass of methyl acetate.

[0092] (Example 5) Adhesive tape 5 was prepared in the same manner as in Example 1, except that the ratio of solvents in the adhesive solution was 60% by mass of ethyl acetate and 30% by mass of butyl acetate.

[0093] (Example 6) Adhesive tape 6 was prepared in the same manner as in Example 1, except that the ratio of solvents in the adhesive solution was 60% by mass of ethyl acetate and 30% by mass of methyl ethyl ketone.

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

[0095] (Example 8) Adhesive tape 8 was prepared in the same manner as in Example 1, except that a die coater was used instead of a microgravure coater.

[0096] (Comparative Example 1) Adhesive tape 9 was prepared in the same manner as in Example 1, except that the solid content concentration of the adhesive solution was changed from 10% by mass to 30% by mass.

[0097] (Comparative Example 2) Adhesive tape 10 was prepared in the same manner as in Example 1, except that the solid content concentration of the adhesive solution was changed from 10% by mass to 1% by mass.

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

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

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

[0101] (Comparative Example 6) Adhesive tape 14 was prepared in the same manner as in Example 1, except that the ratio of solvents in the adhesive solution was 10% by mass of ethyl acetate and 80% by mass of methyl acetate.

[0102] (Comparative Example 7) Adhesive tape 15 was prepared in the same manner as in Example 1, except that the ratio of solvents in the adhesive solution was 10% by mass of ethyl acetate and 80% by mass of butyl acetate.

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

[0104] [evaluation] The double-sided adhesive tapes manufactured in the examples and comparative examples were evaluated using the methods described below. The results of each evaluation are shown in Table 1 (Examples) and Table 2 (Comparative Examples). The number in parentheses in the column for the minimum adhesive strength represents the ratio of the minimum value to the average value.

[0105] [Table 1]

[0106] [Table 2]

[0107] <Thickness of the base material> The thickness of the aforementioned substrate was measured in 0.1 μm units using a Nikon Corporation "DigiMicro MF-501". The average thickness of the substrate was 2.0 μm, which was the average value obtained by measuring the substrate at 10 points in the width direction.

[0108] <Thickness of the adhesive layer> The thickness of the adhesive layer was measured using a Nikon Corporation "Digimicro MF-501". Specifically, the thickness (I) of the adhesive tape with a separator (release layer) was measured. Next, the adhesive at the same location was scraped off with ethyl acetate, and the thickness (II) at that location was measured. Then, the thickness of the adhesive layer was calculated as "thickness (I) - thickness (II)". The tape was measured at 10 points in the width direction, and the uniformity of the adhesive layer was evaluated according to the following criteria. ◎: All 10 points (10 locations) are 1.5 μm ± 0.2 μm. ○: All 10 points (10 locations) are 1.5 μm ± 0.3 μm. ×: Out of 10 points (10 locations), at least one point (1 location) is less than 1.2 μm or greater than 1.8 μm.

[0109] <Environmental Friendliness> Each double-sided adhesive tape comes in a specified size (area: 10cm²). 2 A sample was prepared by cutting out a piece of material, and the release liner was peeled off from one of the adhesive surfaces of the sample, and aluminum foil was attached to that adhesive surface. The release liner covering the other adhesive surface was peeled off to expose the adhesive surface, and this was placed in a 20 mL vial and sealed tightly. Subsequently, the vial containing the sample was heated at 80°C for 30 minutes, and 1.0 mL of the heated gas was injected into a gas chromatograph (GC) using a headspace autosampler to measure the amounts of toluene and n-hexane. The measured values ​​of toluene or n-hexane were converted to 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 performance was evaluated according to the following criteria. ◎: The detected levels of toluene and n-hexane are 100 ppm or less. ○: The detected levels of toluene and n-hexane are between 100 ppm and 1000 ppm. ×: The detected levels of toluene and n-hexane are greater than 1000 ppm.

[0110] The gas chromatograph conditions were as follows: • Column: DB-FFAP 1.0μm (diameter 0.535mm x 30m) Carrier gas: He 5.0 mL / min • Column head pressure: 23kPa (40℃) • Inlet: Split (split ratio 12:1, temperature 250℃) • Column temperature: Start at 40°C, increase the temperature at a rate of 10°C / min to 250°C, and then maintain the temperature at 250°C for 9 minutes. • Detector: FID (Temperature 250°C)

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

[0112] (1) A test plate was prepared by fixing the non-sand-matted side (other side) of a Toray Industries, Inc. black polyester film, Lumirror X30 (38 μm), which had one side sand-matted, to an aluminum plate (0.5 mm) with double-sided tape (DIC Corporation, #8603TNW-10-4). (2) A test specimen was prepared by cutting the sample for measurement (adhesive tape of the present invention) to a width of 20 mm and a length of 100 mm in the flow direction (length direction). A PET film with a thickness of 25 μm was attached to the opposite side of the measurement surface of the double-sided tape. (3) Under an atmosphere of 23°C and 50% relative humidity, the test specimen was pressed onto the test plate using a 2 kg rubber roller at a speed of 300 mm / min for one back-and-forth motion. (4) After pressurization was completed, the test specimens were left for 5 minutes in an atmosphere of 23°C and 50% relative humidity. (5) After the standing period, the test plate was set in one chuck of the tensile testing machine, and the gripping portion of the test piece was clamped in the other chuck. Subsequently, the test piece was peeled off 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 the adhesive strength to the surface of the mat layer was measured.

[0113] The uniformity of the adhesive strength (mat PET) was evaluated by measuring the adhesive strength at 10 locations in the width direction and using the following criteria. ◎: The minimum value is 0.9N / 20mm or higher, and it is 60% or higher of the average value. ○: The minimum value is 0.5 N / 20 mm or higher, and it is 40% or higher of the average value. ×: The minimum value is less than 0.5 N / 20 mm.

[0114] <Shear holding force of adhesive tape measured after 24 hours under a 100g load at 100°C. Displacement distance (holding force) after 24 hours.>

[0115] Each double-sided adhesive tape was cut to a width of 20 mm, and one side of the adhesive layer was backed with 50 μm thick aluminum foil to form a test specimen. The release liner was removed from each double-sided adhesive tape to form the test specimen. The test specimen was then attached to a clean, smooth stainless steel plate (SUS304) surface to create a 20 mm x 20 mm adhesive area, and pressure was applied to the top surface by running a 2 kg roller back and forth once. The specimen was then left for 1 hour under conditions of 23°C and 50% relative humidity, in accordance with JIS Z-0237. Subsequently, a 100 g load was applied in the shear direction under a 100°C atmosphere, and the displacement distance of the tape on the test specimen after 24 hours was measured and evaluated according to the following criteria. ◎: The displacement is 1 mm or less. ○: The displacement distance is greater than 1 mm and less than 2 mm. ×: The displacement is 2 mm or more.

[0116] <180-degree peel adhesion strength (uniformity of adhesive strength (SUS)) on a SUS surface in adhesive tape> One side of each double-sided adhesive tape was attached to a polyethylene terephthalate substrate with a thickness of 25 μm, and the resulting rectangular strips measuring 20 mm wide and 100 mm long were cut to create the adhesive tapes used for measurement. Next, under conditions of 23°C and 50% relative humidity, the adhesive tape was attached to a stainless steel plate (SUS304), a 2kg roller was used to move the top surface of the adhesive tape back and forth once, and then the two were left to stand for 1 hour under conditions of 23°C and 50% relative humidity to create a test piece in which the adhesive tape and the stainless steel plate (SUS304) were pressed together. Next, using a Tensilon peel tester, the strength of the adhesive tape was measured when it was peeled off in a 180° direction at a peeling speed of 300 mm / min, with the stainless steel plate (SUS304) constituting the test piece fixed horizontally.

[0117] The uniformity of the adhesive strength (SUS) was evaluated by measuring the strength at 10 locations in the width direction and using the following criteria. ◎: All 10 locations are within 5.0N / 20mm ± 1.5N / 20mm. ○: All 10 locations are within 5.0N / 20mm ± 2.0N / 20mm. ×: There is at least one location that does not fall within the range of 5.0N / 20mm ± 2.0N / 20mm.

[0118] <Productivity> During the production of each double-sided adhesive tape, we visually inspected whether moisture condensed on the adhesive surface or release film and evaluated it according to the following criteria. ○: No condensation. ×: Condensation occurs.

[0119] <Practicality of Tape> Each double-sided adhesive tape was bonded to 6μm Furukawa Electric's electrolytic copper foil NC-WS, and then Nichiei Shinka's silicone-based protective film SI75-15 (adhesive strength 0.02N / 25mm) was bonded to aluminum foil to create processed products cut to 10mm x 30mm. Subsequently, the processed product was attached to the inside of the metal casing of an Apple iPhone 14 Pro and pressed once with a 100g roller. One minute later, the protective film was peeled off at a speed of 5m / min, and the double-sided tape was checked for lifting or peeling from the metal casing for 10 processed products, and evaluated according to the following criteria. ◎: None of the 10 pieces showed any lifting or peeling. ○: One float is generated. ×: Two or more floats appear.

[0120] The results in Tables 1 and 2 show that a method for manufacturing adhesive tapes, which includes an adhesive layer formation step, can produce a thin adhesive tape with low toluene and n-hexane content but stable adhesive strength by applying an adhesive solution containing 50% to 95% by mass of ethyl acetate, 1% or less by mass of toluene, 1% or less by mass of n-hexane, and a solid content of 5% to 20% by mass to the surface of a substrate with a thickness of 0.5 μm to 5 μm.

[0121] Examples of embodiments of the present invention include the following: <1> The method for manufacturing adhesive tape is characterized by including an adhesive layer formation step, in which an adhesive solution having an ethyl acetate content of 50% to 95% by mass, a toluene content of 1% by mass or less, an n-hexane content of 1% by mass or less, and a solid content 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> In the adhesive layer formation step, the adhesive layer is formed such that the tolerance of the thickness of the adhesive layer is ±0.3 μm. <1> This is a method for manufacturing adhesive tape as described above. <3> In the adhesive layer formation step, the adhesive layer is formed using a microgravure coater, a small-diameter gravure coater, or a die coater. <1> This is a method for manufacturing adhesive tape as described above. <4> The content of the compound having a hydroxyl group in the adhesive solution is 1% by mass or less. <1> This is a method for manufacturing adhesive tape as described above. <5> The compound having a hydroxyl group is an alcohol. <4> This is a method for manufacturing adhesive tape as described above. <6> The adhesive solution contains an acrylic adhesive. <1> This is a method for manufacturing adhesive tape as described above. <7> The adhesive solution contains an isocyanate crosslinking agent, <1> This is a method for manufacturing adhesive tape as described above. <8> The adhesive solution contains a tackifying resin, <1> This is a method for manufacturing adhesive tape as described above. <9> The substrate comprises an adhesive layer on at least one side of the substrate, 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. The adhesive tape is characterized in that, when the 180-degree peel adhesive strength of the adhesive tape is measured 10 times on a mat layer surface with a maximum height roughness (Rz) of 5.2 μm and an arithmetic mean roughness (Ra) of 0.5 μm, the minimum value is 0.5 N / 20 mm or more, and the minimum value when measured 10 times is 0.4 times or more the average value when measured 10 times. <10> The adhesive layer contains an acrylic adhesive, <9> This is the adhesive tape described in [the document]. <11> The adhesive layer has a crosslinked structure derived from an isocyanate crosslinking agent, <9> This is the adhesive tape described in [the document]. <12> The adhesive layer contains a tackifying resin, <9> This is the adhesive tape described in [the document]. <13> The adhesive tape, when its shear holding force is measured under a load of 100g in a 100°C environment, has a displacement distance of 1mm or less after 24 hours. <9> This is the adhesive tape described in [the document]. <14> The adhesive tape has a 180-degree peel adhesive strength to a SUS surface of 3.5 N / 20 mm or more and 20.0 N / 20 mm or less. <9> This is the adhesive tape described in [the document].

Claims

1. A method for producing an adhesive tape, comprising an adhesive layer forming step, wherein the adhesive solution has an ethyl acetate content of 50% to 95% by mass, a toluene content of 1% by mass or less, an n-hexane content of 1% by mass or less, and a solid content 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 an adhesive tape according to claim 1, wherein in the adhesive layer forming step, the adhesive layer is formed such that the tolerance of the thickness of the adhesive layer is ±0.3 μm.

3. The method for manufacturing an adhesive tape according to claim 1, wherein in the adhesive layer formation step, an adhesive layer is formed using a microgravure coater, a small-diameter gravure coater, or a die coater.

4. The method for producing an adhesive tape according to claim 1, wherein the content of a compound having a hydroxyl group in the adhesive solution is 1% by mass or less.

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

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

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

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

9. The substrate comprises an adhesive layer on at least one side of the substrate, 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. The adhesive tape is characterized in that, when the 180-degree peel adhesion strength to the surface of a mat layer having a maximum height roughness (Rz) of 5.2 μm and an arithmetic mean roughness (Ra) of 0.5 μm is measured 10 times, the minimum value is 0.5 N / 20 mm or more, and the minimum value when measured 10 times is 0.4 times or more the average value when measured 10 times.

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 crosslinked structure derived from an isocyanate crosslinking 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 the shear holding force of the adhesive tape is measured after 24 hours when a load of 100g is applied in a 100°C environment, and the displacement distance after 24 hours is 1 mm or less.

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

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