TWI862491B - Adhesive sheet and heat-peelable adhesive tape conveying method - Google Patents

Abstract

The present invention provides an adhesive sheet, which is a heat-peelable adhesive tape having a substrate and an adhesive layer, and the adhesive layer is not easily affected by the heat applied from the substrate side, and the adhesive layer is not easily deteriorated even when used in a roll-to-roll process.

The adhesive sheet of the present invention comprises in order: a first adhesive layer, a first substrate, a second adhesive layer and a second substrate, the first adhesive layer and the first substrate constitute a heat-peelable adhesive tape, the second adhesive layer and the second substrate constitute a laminated portion A, and the laminated portion A is configured in a manner that can be peeled from the heat-peelable adhesive tape.

Description

Method for transporting adhesive sheets and heat-peel adhesive tapes

The present invention relates to an adhesive sheet.

As an adhesive tape used for temporarily fixing a workpiece in the steps of manufacturing electronic parts, there is known an easily peelable adhesive tape that exhibits adhesiveness when temporarily fixed and exhibits peelability by heating when no fixation is required (for example, Patent Document 1). Such an adhesive tape generally has a base material and an adhesive layer disposed on the base material. In addition, when manufacturing the above-mentioned adhesive tape, after the base material and the adhesive layer are stacked to form a laminate, there is a case where the laminate is provided for an inspection step or an adhesive layer processing step. In this step, the so-called roll-to-roll process is mostly used to transport the long strip of the above-mentioned laminated body using a conveyor roller. At this time, friction heat is generated due to contact with the conveyor roller, etc., causing the properties of the adhesive layer to deteriorate.

[Prior Art Literature] [Patent Literature]

[Patent document 1] Japanese Patent Publication No. 2001-131507

The present invention is made to solve the above-mentioned previous problems, and its purpose is to provide an adhesive sheet, which is a heat-peelable adhesive tape having a substrate and an adhesive layer, and the adhesive layer is not easily affected by the heat applied from the substrate side, and even if it is used in a roll-to-roll process, the adhesive layer is not easy to deteriorate.

The adhesive sheet of the present invention comprises in order: a first adhesive layer, a first substrate, a second adhesive layer and a second substrate, the first adhesive layer and the first substrate constitute a heat-peelable adhesive tape, the second adhesive layer and the second substrate constitute a laminated portion A, and the laminated portion A is configured in a manner that can be peeled from the heat-peelable adhesive tape.

In one embodiment, the thickness of the laminated portion A is greater than 10 μm.

In one embodiment, the gel fraction of the second adhesive layer is 20% to 100% by weight.

In one embodiment, after the above-mentioned laminated portion A is heated at 100°C for 30 minutes, the adhesion force A2 of the laminated portion A to the polyethylene terephthalate film is less than 10 times the normal adhesion force A1 of the laminated portion A to the polyethylene terephthalate film.

In one embodiment, the normal adhesion force A1 of the above-mentioned laminated portion A to the polyethylene terephthalate film is 0.05N/20mm~5N/20mm.

According to another aspect of the present invention, a method for conveying a heat-peelable adhesive tape is provided. The conveying method is a method for conveying a heat-peelable adhesive tape having a first substrate and a first adhesive layer, and the conveying method includes: laminating a layered portion A on the side of the first substrate, and conveying the heat-peelable adhesive tape with the layered portion A.

According to the present invention, an adhesive sheet can be provided, which is a heat-peelable adhesive tape having a substrate and an adhesive layer, and the adhesive layer is not easily affected by the heat applied from the substrate side, and the adhesive layer is not easily deteriorated even when provided in a roll-to-roll process.

10: Heat-peel adhesive tape

11: 1st adhesive layer

12: 1st base material

20: Layered part A

21: Second adhesive layer

22: Second base material

100: Adhesive sheet

Figure 1 is a schematic cross-sectional view of an adhesive sheet in one embodiment of the present invention.

A. Overall composition of adhesive sheet

FIG1 is a schematic cross-sectional view of an adhesive sheet of one embodiment of the present invention. The adhesive sheet 100 sequentially comprises: a first adhesive layer 11, a first substrate 12, a second adhesive layer 21, and a second substrate 22. The first adhesive layer 11 and the first substrate 12 constitute a heat-peelable adhesive tape 10. The second adhesive layer 21 and the second substrate 22 constitute a laminated portion A20. The laminated portion A20 is configured to be peelable from the heat-peelable adhesive tape 10. Although not shown, the adhesive sheet may further include any other appropriate layers.

In the present invention, by providing the built-up layer portion A20 on the first substrate 12 side of the heat-peelable adhesive tape 10, the first adhesive layer 11 can be protected from heat applied from the first substrate 12 side (substantially the built-up layer portion A20 side). More specifically, when the heat peelable adhesive tape 10 needs to be provided to a roll-to-roll process (for example, inspection of the adhesive layer surface, processing of the adhesive layer surface, etc.), the heat peelable adhesive tape 10 is provided to the process in the form of a heat peelable adhesive tape 10 (i.e., adhesive sheet 100) having a laminated portion A20 arranged on the side of the first substrate 12, thereby protecting the first adhesive layer 11 from temperature rise due to friction with the conveyor roller, etc. When the heat-peelable adhesive tape 10 is completed through a specific step, the laminated portion A20 is peeled off, and the heat-peelable adhesive tape 10 can be used as a temporary fixing tape in the electronic component manufacturing step. According to the present invention, by having the laminated portion A20 laminated in a peelable manner, the thermal degradation of the adhesive layer (i.e., the first adhesive layer) of the heat-peelable adhesive tape 10 can be prevented, and the heat-peelable adhesive tape 10 can be manufactured to an appropriate thickness that meets the actual use. The heat-peelable adhesive tape 10 can be stored in the form of the heat-peelable adhesive tape 10 (i.e., adhesive sheet 100) with the attached layer portion A20 until it is used.

In one embodiment, the adhesive sheet can be provided in a long strip shape.

B. Heat release adhesive tape

Heat-peel adhesive tape has the characteristic that the adhesive force is reduced or eliminated by heating. There is no particular limitation on the form of such heat-peel adhesive tape, and examples thereof include tapes having an adhesive layer containing heat-expandable microspheres and tapes having an adhesive layer that can be cured by heat. When the heat-peel adhesive tape is used as a sheet for temporarily fixing the processed object during processing of electronic parts (such as ceramic capacitors), when the processed object is subjected to specific processing, the adhesiveness required for temporary fixing is exhibited, and when the heat-peel adhesive tape is peeled off from the processed object after processing, the adhesive force is reduced or eliminated by heating, and good releasability is exhibited. In one embodiment, the heat-peelable adhesive tape has a substrate (first substrate) and an adhesive layer (first adhesive layer) containing an adhesive A and heat-expandable microspheres. Hereinafter, as a representative example of the heat-peelable adhesive tape, a heat-peelable adhesive tape having a first adhesive layer containing heat-expandable microspheres will be described.

The heat-expandable microspheres in the first adhesive layer can foam at a specific temperature. For such an adhesive layer containing heat-expandable microspheres, the heat-expandable microspheres are foamed by heating, thereby generating bumps on the adhesive surface (i.e., the surface of the first adhesive layer), and the adhesive force is reduced or disappears.

The adhesion (before heating) of the above-mentioned heat-peelable adhesive tape to polyethylene terephthalate film (for example, thickness 25μm) is preferably 0.1N/20mm or more, more preferably 1.0N/20mm~50N/20mm, and further preferably 2.0N/20mm~20N/20mm. If it is within this range, for example, a heat-peelable adhesive tape useful as a temporary fixing sheet used in the manufacture of electronic components can be obtained. The adhesion in this manual refers to the adhesion measured by the method of JIS Z 0237:2000 (lamination conditions: 2kg roller back and forth once, peeling speed: 300mm/minute, peeling angle 180°) in an environment of 23°C.

The adhesive force of the above-mentioned heat-peelable adhesive tape after laminating the adhesive surface to the polyethylene terephthalate film and heating is preferably less than 0.2N/20mm, and more preferably less than 0.1N/20mm. In this specification, heating of the heat-peelable adhesive tape refers to heating at a temperature and time at which the heat-expandable microspheres expand or foam, thereby reducing the adhesive force. The heating is, for example, heating at 70℃~270℃ for 1 minute to 10 minutes.

The thickness of the above-mentioned thermal release adhesive tape is preferably 30μm~500μm, and more preferably 40μm~300μm.

B-1. First adhesive layer

The thickness of the first adhesive layer is preferably 1 μm to 30 μm, more preferably 1 μm to 20 μm, and further preferably 1 μm to 10 μm. If it is within this range, a heat-peelable adhesive tape capable of preventing the position of the adherend from being displaced and sinking into the first adhesive layer can be obtained. The thickness of each layer constituting the adhesive sheet can be measured using a ruler, a vernier caliper, or a micrometer. In addition, an electron microscope, an optical microscope, an atomic force microscope, or the like can also be used. Furthermore, the interface of adjacent layers can be determined according to the different compositions and the thickness of each layer can be measured. As methods for distinguishing interfaces, for example, there are spectroscopic analysis such as Raman spectroscopy, infrared spectroscopy, and X-ray photoelectron spectroscopy; mass analysis methods such as matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOFMS) or time-of-flight secondary ion mass spectrometry (TOF-SIMS).

The elastic modulus of the first adhesive layer obtained by nanoindentation at 25° C. is preferably less than 100 MPa, more preferably 0.1 MPa to 50 MPa, and further preferably 0.1 MPa to 10 MPa. If it is within this range, a heat-peelable adhesive tape capable of preventing the positional displacement of the adherend and the sinking into the first adhesive layer can be obtained. The elastic modulus obtained by the nanoindentation method refers to the elastic modulus obtained by continuously measuring the load and penetration depth of the indenter when the indenter is pressed into the sample (e.g., the adhesive surface) during loading and unloading. The load-indentation depth curve is used to obtain the elastic modulus. In this specification, the elastic modulus obtained by the nanoindentation method refers to the elastic modulus measured in the above manner under the measurement conditions of load: 1mN, load, unloading speed: 0.1mN/s, holding time: 1s. Furthermore, when the first adhesive layer contains thermally expandable microspheres, the elastic modulus of the first adhesive layer obtained by nanoindentation is the elastic modulus of the portion where the thermally expandable microspheres do not exist and measured by the above-mentioned measurement method.

(Adhesive A)

As the adhesive A constituting the first adhesive layer, any appropriate adhesive can be used as long as the effect of the present invention can be obtained. In one embodiment, as the adhesive A, a hardening adhesive is used, preferably an active energy ray hardening adhesive. In another embodiment, as the adhesive A, a pressure-sensitive adhesive is used. As pressure-sensitive adhesives, for example, acrylic adhesives, rubber adhesives, etc. can be listed.

(Active energy ray-hardening adhesive)

As the resin material constituting the above-mentioned active energy ray-curing adhesive, for example, there can be cited the resin materials described in UV Curing System (Kato Kiyoshi, published by the General Technology Center, (1989)), Photocuring Technology (Technical Information Association (2000)), Japanese Patent Publication No. 2003-292916, Japanese Patent No. 4151850, etc. More specifically, there can be cited the resin material (R1) containing a polymer as a masterbatch and an active energy ray-reactive compound (monomer or oligomer), the resin material (R2) containing an active energy ray-reactive polymer, etc.

Examples of the polymers used as masterbatches include natural rubber, polyisobutylene rubber, styrene-butadiene rubber, styrene-isoprene-styrene block copolymer rubber, recycled rubber, butyl rubber, polyisobutylene rubber, nitrile rubber (NBR), and other rubber-based polymers; silicone-based polymers; acrylic-based polymers, etc. These polymers can be used alone or in combination of two or more.

As the above-mentioned active energy line reactive compound, for example, there can be listed photoreactive monomers or oligomers having functional groups with carbon-carbon multiple bonds such as multiple acryl groups, methacryl groups, vinyl groups, allyl groups, ethynyl groups, etc. Among them, it is preferred to use a compound having an ethylenic unsaturated functional group, and it is more preferred to use a (meth) acrylic compound having an ethylenic unsaturated functional group. Since compounds having an ethylenic unsaturated functional group can easily generate free radicals using ultraviolet rays, if such compounds are used, a first adhesive layer that can be cured in a short time can be formed. In addition, if a (meth) acrylic compound having an ethylenic unsaturated functional group is used, an adhesive layer having a moderate hardness after curing (specifically, a hardness that allows the thermally expandable microspheres to foam well) can be formed. Specific examples of photoreactive monomers or oligomers include: trihydroxymethylpropane tri(meth)acrylate, tetrahydroxymethylmethane tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol monohydroxy penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, polyethylene glycol di(meth)acrylate, (meth)acrylic acid urethane compounds and other (meth)acrylic acid containing (meth) compounds; dimers to pentamers of the (meth)acrylic acid containing compounds, etc. These compounds can be used alone or in combination of two or more.

Furthermore, as the above-mentioned active energy ray reactive compound, monomers such as epoxide butadiene, glycidyl methacrylate, acrylamide, vinyl siloxane, etc., or oligomers composed of the monomers can also be used. The resin material (R1) containing these compounds can be cured by high energy rays such as ultraviolet rays and electron beams.

Furthermore, as the above-mentioned active energy line reactive compound, a mixture of organic salts such as onium salts and compounds having multiple heterocyclic rings in the molecule can be used. Regarding the mixture, by irradiation with active energy lines (for example, ultraviolet rays, electron beams), the organic salts are dissociated to generate ions, which become starting species to cause the ring-opening reaction of the heterocyclic rings, and a three-dimensional network structure can be formed. As the above-mentioned organic salts, for example, iodonium salts, phosphonium salts, antimony salts, coronium salts, borate salts, etc. can be listed. As the heterocyclic ring in the above-mentioned compound having multiple heterocyclic rings in the molecule, ethylene oxide, cyclohexane, cyclopentane (oxolane), ethylene sulfide, aziridine, etc. can be listed.

In the resin material (R1) comprising a polymer as a masterbatch and an active energy ray reactive compound, the content ratio of the active energy ray reactive compound is preferably 0.1 to 500 parts by weight, more preferably 1 to 300 parts by weight, and further preferably 10 to 200 parts by weight relative to 100 parts by weight of the polymer as a masterbatch.

As the above-mentioned active energy line reactive polymer, for example, there can be listed polymers having active energy line reactive functional groups having carbon-carbon multiple bonds such as acryl, methacryl, vinyl, allyl, ethynyl, etc. It is preferred to use a compound (polymer) having an ethylenic unsaturated functional group, and it is more preferred to use a (meth) acrylic polymer having an acryl or methacryl group. As a specific example of a polymer having an active energy line reactive functional group, there can be listed polymers composed of multifunctional (meth) acrylates, etc.

The resin material (R2) containing the above-mentioned active energy ray reactive polymer may further contain the above-mentioned active energy ray reactive compound (monomer or oligomer).

The above-mentioned active energy ray-curing adhesive can be cured by irradiation with active energy rays. In the above-mentioned heat-peel adhesive tape, after the adherend is attached before the adhesive A is cured, the adhesive A is cured by irradiation with active energy rays, thereby being able to closely adhere to the adherend. As active energy rays, for example, there can be listed: gamma rays, ultraviolet rays, visible rays, infrared rays (heat rays), radio frequency waves, alpha rays, beta rays, electron beams, plasma currents, ionizing rays, particle rays, etc. The wavelength of the active energy rays, the irradiation amount and other conditions can be set to any appropriate conditions according to the type of resin material used. For example, ultraviolet rays with an irradiation amount of 10~1000mJ/ ^cm2 can be irradiated to cure the adhesive A.

(Acrylic adhesive)

Examples of the acrylic adhesive include acrylic adhesives using as base polymers acrylic polymers (homopolymers or copolymers) using as monomer components one or more alkyl (meth)acrylates. Specific examples of alkyl (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, 1,2-butyl (meth)acrylate, 2,3-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, 1,2-butyl ... Ester, 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, eicosyl (meth)acrylate and the like C1-20 alkyl (meth)acrylate. Among them, alkyl (meth)acrylates having a linear or branched alkyl group with 4 to 18 carbon atoms can be preferably used.

、乙烯基吡

、乙烯基吡咯、乙烯基咪唑、乙烯基

唑、乙烯基嗎啉、N-乙烯基羧醯胺類、苯乙烯、α-甲基苯乙烯、N-乙烯基己內醯胺等乙烯基系單體；丙烯腈、甲基丙烯腈等氰基丙烯酸酯單體；(甲基)丙烯酸縮水甘油酯等含環氧基丙烯酸系單體；(甲基)丙烯酸聚乙二醇酯、(甲基)丙烯酸聚丙二醇酯、(甲基)丙烯酸甲氧基乙二醇酯、(甲基)丙烯酸甲氧基聚丙二醇酯等二醇系丙烯酸酯單體；(甲基)丙烯酸四氫糠酯、氟(甲基)丙烯酸酯、矽酮(甲基)丙烯酸酯等具有雜環、鹵素原子、矽原子等之丙烯酸酯系單體； 己二醇二(甲基)丙烯酸酯、(聚)乙二醇二(甲基)丙烯酸酯、(聚)丙二醇二(甲基)丙烯酸酯、新戊二醇二(甲基)丙烯酸酯、季戊四醇二(甲基)丙烯酸酯、三羥甲基丙烷三(甲基)丙烯酸酯、季戊四醇三(甲基)丙烯酸酯、二季戊四醇六(甲基)丙烯酸酯、環氧丙烯酸酯、聚酯丙烯酸酯、丙烯酸胺基甲酸酯等多官能單體；異戊二烯、丁二烯、異丁烯等烯烴系單體；乙烯基醚等乙烯基醚系單體等。該等單體成分可單獨使用或組合使用2種以上。 In order to achieve the improvement of cohesion, heat resistance, crosslinking, etc., the acrylic polymer may contain units corresponding to other monomer components that can be copolymerized with the above-mentioned alkyl (meth)acrylate as needed. Examples of such monomer components include: carboxyl-containing monomers such as acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid; acid anhydride monomers such as maleic anhydride and itaconic anhydride; hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, hydroxyhexyl (meth)acrylate, hydroxyoctyl (meth)acrylate, hydroxydecyl (meth)acrylate, hydroxylauryl (meth)acrylate, methacrylic acid (4-hydroxymethylcyclohexyl) methyl ester and other hydroxyl-containing monomers; styrene sulfonic acid, allyl sulfonic acid, 2-(meth)acrylamide-2-methylpropanesulfonic acid, (meth)acrylamide propanesulfonic acid, (meth)acrylate sulfopropyl ester, (meth)acryloxynaphthalenesulfonic acid and other sulfonic acid group-containing monomers; (meth)acrylamide, N,N-dimethyl (meth)acrylamide, N-butyl (meth)acrylamide, N-hydroxymethyl (meth)acrylamide, N-hydroxymethylpropane (meth)acrylamide and other (N-substituted) amide monomers; aminoethyl (meth)acrylate, (meth) (Meth)acrylic acid aminoalkyl ester monomers such as N,N-dimethylaminoethyl acrylate and tert-butylaminoethyl (meth)acrylate; (meth)acrylic acid alkoxyalkyl ester monomers such as methoxyethyl (meth)acrylate and ethoxyethyl (meth)acrylate; maleimide monomers such as N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, and N-phenylmaleimide; N-methyliconimide, N-ethyliconimide, N-butyliconimide, N-octyliconimide, Iconimide monomers such as 1,2-diaminobenzylamine, N-2-ethylhexyliconimide, N-cyclohexyliconimide, and N-lauryliconimide; succinimide monomers such as N-(meth)acryloyloxymethylenesuccinimide, N-(meth)acryloyl-6-oxyhexamethylenesuccinimide, and N-(meth)acryloyl-8-oxyoctamethylenesuccinimide; vinyl acetate, vinyl propionate, N-vinylpyrrolidone, methylvinylpyrrolidone, vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperidone, etc.

, vinyl pyridine

, vinylpyrrole, vinylimidazole, vinyl

Vinyl monomers such as oxazole, vinyl morpholine, N-vinyl carboxylic acid amides, styrene, α-methylstyrene, N-vinyl caprolactam, etc.; cyanoacrylate monomers such as acrylonitrile and methacrylonitrile; epoxy group-containing acrylic monomers such as glycidyl (meth)acrylate; diol acrylic monomers such as polyethylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate, methoxyethylene glycol (meth)acrylate, methoxypolypropylene glycol (meth)acrylate; acrylic monomers having heterocyclic rings, halogen atoms, silicon atoms, etc. such as tetrahydrofurfuryl (meth)acrylate, fluoro(meth)acrylate, silicone (meth)acrylate; Polyfunctional monomers such as hexanediol di(meth)acrylate, (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, trihydroxymethylpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, epoxy acrylate, polyester acrylate, and urethane acrylate; olefin monomers such as isoprene, butadiene, and isobutylene; vinyl ether monomers such as vinyl ether, etc. These monomer components can be used alone or in combination of two or more.

(Rubber-based adhesive)

Examples of the above-mentioned rubber adhesives include rubber adhesives using natural rubber, polyisoprene rubber, styrene-butadiene (SB) rubber, styrene-isoprene (SI) rubber, styrene-isoprene-styrene block copolymer (SIS) rubber, styrene-butadiene-styrene block copolymer (SBS) rubber, styrene-ethylene-butylene-styrene block copolymer (SEBS) rubber, styrene-ethylene-propylene-styrene block copolymer (SEPS) rubber, styrene-ethylene-propylene block copolymer (SEP) rubber, recycled rubber, butyl rubber, polyisobutylene, synthetic rubbers such as modified products thereof, etc. as base polymers.

(Additive)

The above-mentioned adhesive A may contain any appropriate additives as needed. Examples of such additives include: initiators, crosslinkers, adhesive agents, plasticizers, pigments, dyes, fillers, anti-aging agents, conductive materials, antistatic agents, ultraviolet absorbers, light stabilizers, stripping modifiers, softeners, surfactants, flame retardants, antioxidants, etc.

(Thermal expansion microspheres)

In one embodiment, the first adhesive layer contains heat-expandable microspheres. The first adhesive layer containing heat-expandable microspheres expands or foams the heat-expandable microspheres by heating, resulting in unevenness on the adhesive surface, which reduces or eliminates the adhesive force. If a heat-peelable adhesive tape having such a first adhesive layer is used as a temporary fixing material, the temporarily fixed adherend can be easily peeled off.

As the above-mentioned heat-expandable microspheres, any appropriate heat-expandable microspheres can be used as long as they are microspheres that can expand or foam by heating. As the above-mentioned heat-expandable microspheres, for example, microspheres obtained by enclosing a substance that easily expands by heating in an elastic shell can be used. Such heat-expandable microspheres can be manufactured by any appropriate method, such as a coagulation method, an interfacial polymerization method, etc.

Examples of substances that easily expand by heating include: propane, propylene, butene, n-butane, isobutane, isopentane, neopentane, n-pentane, n-hexane, isohexane, heptane, octane, petroleum ether, methane halides, tetraalkylsilane and other low-boiling point liquids; azodicarbonamide that vaporizes by thermal decomposition, etc.

基酯、(甲基)丙烯酸環己酯、(甲基)丙烯酸苄酯、丙烯酸β-羧基乙酯等(甲基)丙烯酸酯；苯 乙烯、α-甲基苯乙烯、氯苯乙烯等苯乙烯單體；丙烯醯胺、取代丙烯醯胺、甲基丙烯醯胺、取代甲基丙烯醯胺等醯胺單體等構成之聚合物。由該等單體構成之聚合物可為均聚物，亦可為共聚物。作為該共聚物，例如可列舉偏二氯乙烯-甲基丙烯酸甲酯-丙烯腈共聚物、甲基丙烯酸甲酯-丙烯腈-甲基丙烯腈共聚物、甲基丙烯酸甲酯-丙烯腈共聚物、丙烯腈-甲基丙烯腈-伊康酸共聚物等。 Examples of the material constituting the shell include: nitrile monomers such as acrylonitrile, methacrylonitrile, α-chloroacrylonitrile, α-ethoxyacrylonitrile, and fumaronitrile; carboxylic acid monomers such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, and citric acid; vinylidene chloride; vinyl acetate; methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, isobutyl (meth)acrylate, and

The present invention relates to a polymer composed of (meth)acrylates such as (meth)acrylates such as cyclohexyl (meth)acrylate, benzyl (meth)acrylate, and β-carboxyethyl acrylate; styrene monomers such as styrene, α-methylstyrene, and chlorostyrene; and amide monomers such as acrylamide, substituted acrylamide, methacrylamide, and substituted methacrylamide. The polymer composed of these monomers may be a homopolymer or a copolymer. Examples of the copolymer include vinylidene chloride-methyl methacrylate-acrylonitrile copolymer, methyl methacrylate-acrylonitrile-methacrylonitrile copolymer, methyl methacrylate-acrylonitrile copolymer, and acrylonitrile-methacrylonitrile-itaconic acid copolymer.

As the above-mentioned thermally expandable microspheres, inorganic foaming agents or organic foaming agents can also be used. Examples of inorganic foaming agents include: ammonium carbonate, ammonium bicarbonate, sodium bicarbonate, ammonium nitrite, sodium borohydride, various azides, and the like. Furthermore, examples of organic foaming agents include: chlorofluorinated alkane compounds such as trichloromonofluoromethane and dichloromonofluoromethane; azo compounds such as azobisisobutyronitrile, azodicarbonamide, and barium azodicarboxylate; hydrazines such as p-toluenesulfonylhydrazine, diphenylsulfonium-3,3'-disulfonylhydrazine, 4,4'-oxybis(benzenesulfonylhydrazine), and allylbis(sulfonylhydrazine); Series compounds; p-tolylsulfonamidourea, 4,4'-oxybis(benzenesulfonamidourea) and other amine urea series compounds; 5-oxo-1,2,3,4-thiazole and other triazole series compounds; N,N'-dinitrosopentamethylenetetramine, N,N'-dimethyl-N,N'-dinitroso-p-terephthalamide and other N-nitroso series compounds, etc.

The above-mentioned heat-expandable microspheres can also be commercially available. Specific examples of commercially available heat-expandable microspheres include: Matsumoto Microspheres (grades: F-30, F-30D, F-36D, F-36LV, F-50, F-50D, F-65, F-65D, FN-100SS, FN-100SSD, FN-180SS, FN-180SSD, F-190D, F-260D, F-2800D) manufactured by Matsumoto Oil & Pharmaceutical Co., Ltd. The product name "Expancel" manufactured by Fillite Corporation (grades: 053-40, 031-40, 920-40, 909-80, 930-120), "DAIFOAM" manufactured by Wu Yu Chemical Industry Co., Ltd. (grades: H750, H850, H1100, S2320D, S2640D, M330, M430, M520), "ADVANCELL" manufactured by Sekisui Chemical Industry Co., Ltd. (grades: EML101, EMH204, EHM301, EHM302, EHM303, EM304, EHM401, EM403, EM501), etc.

The particle size of the above-mentioned heat-expandable microspheres before heating is preferably 0.5μm~80μm, more preferably 5μm~45μm, further preferably 10μm~20μm, and particularly preferably 10μm~15μm. Therefore, when the average particle size is used to describe the particle size of the above-mentioned heat-expandable microspheres before heating, it is preferably 6μm~45μm, and more preferably 15μm~35μm. The above-mentioned particle size and average particle size are values obtained by the particle size distribution measurement method in the laser scattering method.

The above-mentioned heat-expandable microspheres preferably have a moderate strength that does not break before the volume expansion rate is preferably 5 times or more, more preferably 7 times or more, and further preferably 10 times or more. When using such heat-expandable microspheres, the adhesive force can be effectively reduced by heat treatment.

The content ratio of the heat-expandable microspheres in the first adhesive layer can be appropriately set according to the desired adhesive force reduction, etc. The content ratio of the heat-expandable microspheres is, for example, 1 part by weight to 150 parts by weight, preferably 10 parts by weight to 130 parts by weight, and further preferably 25 parts by weight to 100 parts by weight, relative to 100 parts by weight of the base polymer forming the first adhesive layer.

B-2. The first substrate

Examples of the first substrate include resin sheets, nonwoven fabrics, paper, metal foils, woven fabrics, rubber sheets, foam sheets, laminates thereof (particularly laminates containing resin sheets), etc. Examples of the resin constituting the resin sheet include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), polyethylene (PE), polypropylene (PP), ethylene-propylene copolymer, ethylene-vinyl acetate copolymer (EVA), polyamide (nylon), wholly aromatic polyamide (aromatic polyamide), polyimide (PI), polyvinyl chloride (PVC), polyphenylene sulfide (PPS), fluorine-based resin, polyetheretherketone (PEEK), etc. Examples of nonwoven fabrics include nonwoven fabrics obtained from heat-resistant natural fibers such as Manila hemp nonwoven fabrics, and synthetic resin nonwoven fabrics such as polypropylene resin nonwoven fabrics, polyethylene resin nonwoven fabrics, and ester resin nonwoven fabrics.

The thickness of the first substrate can be set to any appropriate thickness according to the required strength or flexibility, and the purpose of use. The thickness of the substrate is preferably less than 1000μm, more preferably 1μm~1000μm, further preferably 1μm~500μm, particularly preferably 3μm~300μm, and most preferably 5μm~250μm.

The first substrate may also be subjected to surface treatment. Examples of surface treatment include: corona treatment, chromic acid treatment, ozone exposure, flame exposure, high voltage electric shock exposure, ionizing radiation treatment, coating treatment using a primer, etc. If such surface treatment is performed, the adhesion between the first adhesive layer and the substrate can be improved. In particular, coating treatment using an organic coating material is preferred in terms of improving adhesion and preventing the first adhesive layer from being easily damaged during peeling. The surface treatment layer may be formed on the side of the first adhesive layer.

As the above-mentioned organic coating material, for example, the materials described in Plastic Hard Coating Material II (CMC Publishing, (2004)) can be cited. Preferably, a urethane polymer is used, and more preferably, polyacrylic urethane, polyester urethane or such precursors are used. The reason is that the coating and coating on the substrate are simple, and a variety of materials can be selected industrially and can be obtained cheaply. The urethane polymer is, for example, a polymer of a reaction mixture containing an isocyanate monomer and a monomer containing an alcohol hydroxyl group (for example, a hydroxyl-containing acrylic compound or a hydroxyl-containing ester compound). The organic coating material may also contain chain extenders such as polyamines, anti-aging agents, oxidation stabilizers, etc. as arbitrary additives. The thickness of the organic coating layer is not particularly limited, for example, it is preferably about 0.1μm~10μm, preferably about 0.1μm~5μm, and more preferably about 0.5μm~5μm. The organic coating layer can be formed by using any appropriate printing method on the above-mentioned organic coating material, for example.

B-3. Middle layer

The heat-peelable adhesive tape may further include an intermediate layer between the first adhesive layer and the first substrate. Examples of materials constituting the intermediate layer include silicone polymers, epoxy polymers, polycarbonate polymers, vinyl polymers, acrylic polymers, urethane polymers, polyester polymers, polyolefin polymers, polyamide polymers, polyimide polymers, and unsaturated hydrocarbon polymers. If such polymer materials are used, the type of monomer, crosslinking agent, degree of polymerization, etc. are appropriately selected, so that the intermediate layer having the above-mentioned elastic modulus can be easily formed. The above-mentioned polymer materials can be used alone or in combination of two or more.

In one embodiment, a resin material that can be cured by irradiation with active energy rays is used as a material constituting the above-mentioned intermediate layer. If a resin material that can be cured by irradiation with active energy rays is used, the elastic modulus of the intermediate layer can be increased by irradiating the active energy rays at an appropriate time, and the adjustment of the elastic modulus also becomes easier. If such a material is used to form the intermediate layer, when the adhesive sheet is attached, the elasticity is lower and the flexibility is higher, and the handling is excellent. After attachment, by irradiating the active energy rays, an adhesive sheet with an elastic modulus that can be adjusted to the above range can be obtained.

As resin materials that can be cured by irradiation with active energy rays, for example, there can be listed: the resin material (R1) containing a polymer as a masterbatch and an active energy ray-reactive compound (monomer or oligomer) described in the above B-1, the resin material (R2) containing an active energy ray-reactive polymer, etc. In one embodiment, for the active energy ray-reactive compound in the resin material (R1) used as the material of the intermediate layer, a compound having an ethylenically unsaturated functional group can be used. In addition, in one embodiment, as the active energy ray-reactive polymer in the resin material (R2), a compound (polymer) having an ethylenically unsaturated functional group can be used.

Furthermore, as the material constituting the above-mentioned intermediate layer, a hot-melt resin composed of thermoplastic resins such as ethylene-vinyl acetate copolymer, polypropylene resin, and polyamide resin can be used.

The above-mentioned intermediate layer may further include any appropriate additives as needed. Examples of such additives include: initiators, crosslinkers, adhesion promoters, plasticizers, pigments, dyes, fillers, anti-aging agents, conductive materials, antistatic agents, ultraviolet absorbers, light stabilizers, stripping modifiers, softeners, surfactants, flame retardants, antioxidants, etc.

The thickness of the middle layer is preferably 1μm~200μm, more preferably 5μm~50μm, and further preferably 10μm~40μm.

C. Layered part A

As described above, the laminated portion A has a second adhesive layer and a second substrate. The adhesive layer generally has a lower thermal conductivity than the substrate. In the present invention, the laminated portion A including such an adhesive layer (second adhesive layer) is used to protect the thermal peelable adhesive tape, thereby preventing the first adhesive layer (adhesive layer of the thermal peelable adhesive tape) from thermal degradation.

The adhesion A1 (normal adhesion A1) of the above-mentioned laminated portion A to the polyethylene terephthalate film (for example, with a thickness of 50 μm) is preferably 0.04N/20mm~10N/20mm, more preferably 0.05N/20mm~5N/20mm, further preferably 0.08N/20mm~4.5N/20mm, further preferably 0.1N/20mm~2.5N/20mm, and particularly preferably 0.15N/20mm~1.2N/20mm. If it is within this range, it is possible to obtain an adhesive sheet (i.e., a laminate of the above-mentioned heat-peelable adhesive tape and laminated portion A) in which the laminated portion A is not easily peeled off from the heat-peelable adhesive tape when the adhesive sheet is provided in a specific step, and the unnecessary laminated portion A can be easily peeled off from the heat-peelable adhesive tape after the specific step.

After the above-mentioned laminated portion A is heated at 100°C for 30 minutes, the adhesion A2 (adhesion A2 after heating) to the polyethylene terephthalate film (for example, thickness 50μm) is preferably 0.05N/20mm~10.0N/20mm, more preferably 0.08N/20mm~5.0N/20mm, and further preferably 0.10N/20mm~1.5N/20mm. If it is within this range, the laminated portion A can have the required peeling force even if the temperature of the adhesive sheet rises when the adhesive sheet is provided in a specific step. Furthermore, the above-mentioned adhesion after heating is the adhesion in a 23°C environment when the temperature of the second adhesive layer drops to 23°C after heating at the above-mentioned temperature.

The above-mentioned adhesive force A2 after heating is preferably less than 10 times, more preferably less than 5 times, further preferably 0.001 times to 2.5 times, and particularly preferably 0.001 times to 1.8 times relative to the above-mentioned normal adhesive force A1. If it is within this range, the laminated part A can have the required peeling force even if the temperature of the adhesive sheet rises when the adhesive sheet is provided to a specific step.

The thickness of the above-mentioned laminated portion A is preferably 10 μm or more, more preferably 20 μm or more, further preferably 30 μm or more, particularly preferably 50 μm to 500 μm, and most preferably 50 μm to 300 μm. If the thickness of the laminated portion A is 10 μm or more, thermal degradation of the first adhesive layer can be significantly prevented.

C-1. Second adhesive layer

The thickness of the second adhesive layer is preferably 1μm~100μm, more preferably 5μm~80μm, and further preferably 5μm~50μm. If it is within this range, the thermal degradation of the first adhesive layer can be significantly prevented.

The second adhesive layer typically includes an adhesive B based on a specific polymer. As the adhesive B, it is also preferred to use a pressure-sensitive adhesive. Examples of the pressure-sensitive adhesive used in the second adhesive layer include acrylic adhesives, rubber adhesives, vinyl alkyl ether adhesives, silicone adhesives, polyester adhesives, polyamide adhesives, urethane adhesives, and styrene-diene block copolymer adhesives. Among them, acrylic adhesives or silicone adhesives are preferred. Furthermore, the above adhesives can be used alone or in combination of two or more.

As the acrylic adhesive contained in the second adhesive layer, for example, the adhesive described in the above-mentioned B-1 can be used.

As the silicone adhesive contained in the second adhesive layer, any appropriate adhesive can be used. As the above-mentioned silicone adhesive, for example, a silicone adhesive using a silicone rubber or silicone resin containing an organic polysiloxane as a base polymer can be preferably used. As the base polymer constituting the silicone adhesive, a base polymer obtained by cross-linking the above-mentioned silicone rubber or silicone resin can be used. Furthermore, in this manual, the distinction between "silicone rubber" and "silicone resin" is based on "Technical Information Association Adhesive (Film, Tape) Material Design and Functional Assignment 1st Edition September 30, 2009 Pages 222-228". That is, "silicone rubber" refers to silicone with a straight chain structure composed of diorganosiloxane (D unit), and the silicone rubber has a viscosity of about 10000 Pa‧s. "Silicone resin" refers to silicone containing triorganosilhemioxane (M unit) and silicate (Q unit) and having a branched chain structure.

The gel fraction of the second adhesive layer is preferably 20% to 100% by weight, more preferably 30% to 99% by weight, and further preferably 50% to 99% by weight. If it is within this range, the increase in adhesion after heating can be suppressed, and the laminated part A with excellent peeling properties can be formed. The gel fraction is measured as follows.

<Gel fraction measurement method>

About 0.1g of the second adhesive layer was sampled and accurately weighed (the weight of the sample), and the sample was wrapped with a mesh sheet (trade name "NTF-1122", manufactured by Nitto Denko Co., Ltd.), and immersed in about 50ml of toluene at room temperature for 1 week. Then, the solvent-insoluble components (contents of the mesh sheet) were taken out of the toluene, dried at 70°C for about 2 hours, and the solvent-insoluble components after drying were weighed (weight after immersion and drying), and the gel fraction (weight %) was calculated by the following formula (a).

Gel fraction (weight %) = [(weight after immersion and drying)/(weight of sample)] × 100 (a)

The base polymer constituting the above-mentioned adhesive B preferably has an OH group or a COOH group. The reason is that if such a base polymer is used, a crosslinking agent can be used to adjust the above-mentioned gel fraction.

C-2. Second base material

As the above-mentioned second substrate, for example, resin sheets, nonwoven fabrics, paper, metal foil, woven fabrics, rubber sheets, foam sheets, laminates thereof (especially laminates containing resin sheets), etc. are listed. Resin sheets are preferred. As resins constituting the resin sheets, for example, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), polyethylene (PE), polypropylene (PP), ethylene-propylene copolymer, ethylene-vinyl acetate copolymer (EVA), polyamide (nylon), wholly aromatic polyamide (aromatic polyamide), polyimide (PI), polyvinyl chloride (PVC), polyphenylene sulfide (PPS), fluorine-based resins, polyetheretherketone (PEEK), etc. are listed. Among them, PET or PI is preferred.

The thickness of the second substrate is preferably 8μm~400μm, more preferably 15μm~300μm, and particularly preferably 25μm~200μm. If it is within this range, the thermal degradation of the first adhesive layer can be significantly prevented.

The second substrate may also be subjected to surface treatment. Examples of surface treatment include the treatment described in item B-2 above. The surface treatment layer may be formed on the surface on the side of the second adhesive layer.

D. Adhesive sheet manufacturing method

The adhesive sheet of the present invention can be manufactured by any appropriate method. In one embodiment, after forming a heat-peelable adhesive tape, the laminated portion A is laminated on the first substrate of the heat-peelable adhesive tape on the opposite side of the first adhesive layer via the second adhesive layer, thereby manufacturing the above-mentioned adhesive sheet.

The above-mentioned heat-peelable adhesive tape can be manufactured by any appropriate method. For example, the following methods can be cited for the above-mentioned heat-peelable adhesive tape: a method of directly applying an adhesive layer-forming composition A including an adhesive A for forming a first adhesive layer (when forming a first adhesive layer including heat-expandable microspheres, further including heat-expandable microspheres) on a first substrate; or a method of transferring a coating layer formed by applying the adhesive layer-forming composition A on any appropriate substrate to the first substrate, etc. The adhesive layer-forming composition A can include any appropriate solvent. Furthermore, when forming the first adhesive layer containing heat-expandable microspheres, after forming an adhesive coating layer using a composition containing adhesive A, heat-expandable microspheres are sprinkled on the adhesive coating layer, and then the heat-expandable microspheres are embedded in the coating layer using a laminating press, thereby forming the first adhesive layer containing heat-expandable microspheres.

The content ratio of the thermally expandable microspheres in the adhesive layer forming composition A is preferably 5% to 95% by weight, more preferably 10% to 70% by weight, and further preferably 10% to 50% by weight relative to the weight of the solid component of the adhesive layer forming composition.

The above-mentioned laminated portion A can be manufactured by any appropriate method. For example, the following methods can be cited for the above-mentioned laminated portion A: a method of directly applying an adhesive layer forming composition B containing an adhesive B forming a second adhesive layer on a second substrate; or a method of transferring a coating layer formed by applying the adhesive layer forming composition B on any appropriate substrate to the second substrate, etc. The adhesive layer forming composition B can contain any appropriate solvent.

As a coating method for each of the above-mentioned compositions, any appropriate coating method can be adopted. For example, each layer can be formed by drying after coating. As coating methods, for example, coating methods using a multi-coater, a die coater, a gravure coater, an applicator, etc. can be listed. As drying methods, for example, natural drying, heating drying, etc. can be listed. The heating temperature in the case of heating drying can be set to any appropriate temperature according to the characteristics of the substance to be dried.

E. How to transport thermal release adhesive tape

The method for conveying the heat-peelable adhesive tape of the present invention is the method for conveying the heat-peelable adhesive tape, which includes: laminating the laminating portion A on the first substrate side of the heat-peelable adhesive tape having the first substrate and the first adhesive layer, and conveying the heat-peelable adhesive tape with the laminating portion A. As described above, the laminating portion A includes the second adhesive layer and the second substrate. The laminating portion A is configured in a manner of laminating the second substrate via the second adhesive layer on the first substrate of the heat-peelable adhesive tape on the side opposite to the first adhesive layer.

In one embodiment, the conveying method includes conveying the heat-peelable adhesive tape (substantially the heat-peelable adhesive tape with the deposited layer portion A) by a conveying roller. The heat-peelable adhesive tape with the deposited layer portion A is preferably conveyed in a manner that the deposited layer portion A becomes the side of the conveying roller. According to the conveying method of the present invention, by conveying the heat-peelable adhesive tape with the deposited layer portion A, the first adhesive layer can be protected from temperature rise due to friction with the conveying roller. According to the present invention, by providing a peelable laminated portion A20, the adhesive layer (i.e., the first adhesive layer) of the heat-peelable adhesive tape can be prevented from deteriorating, and the heat-peelable adhesive tape can be made into a suitable thickness that meets the actual use.

[Implementation example]

The present invention is specifically described below by way of examples, but the present invention is not limited to these examples. The evaluation method in the examples is as follows. In addition, in the examples, unless otherwise specified, "parts" and "%" are based on weight.

[Implementation Example 1]

An adhesive solution was prepared by mixing 100 parts by weight of an acrylic copolymer (2-ethylhexyl acrylate: acrylic acid = 95 parts by weight: 5 parts by weight), 3 parts by weight of an epoxy crosslinking agent (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name "TETRAD C"), and toluene. The adhesive solution was applied to a PET film (thickness: 50 μm) as the second substrate so that the thickness after drying was 5 μm and dried to form a second adhesive layer. A PET separator film (thickness: 38 μm) was attached to the second adhesive layer to obtain a laminated portion A (second substrate (thickness: 50 μm)/second adhesive layer (thickness: 5 μm)/separator film).

[Example 2]

As the second substrate, a polyimide film (thickness: 50 μm) was used instead of the PET film (thickness: 50 μm). In addition, the laminated part A (second substrate (thickness: 50 μm)/second adhesive layer (thickness: 5 μm)/isolation film) was obtained in the same manner as in Example 1.

[Implementation Example 3]

As the second substrate, a PET film (thickness: 25 μm) was used instead of a PET film (thickness: 50 μm). In addition, the laminated portion A (second substrate (thickness: 25 μm)/second adhesive layer (thickness: 5 μm)/isolation film) was obtained in the same manner as in Example 1.

[Implementation Example 4]

As the second substrate, a PET film (thickness: 100 μm) was used instead of a PET film (thickness: 50 μm). In addition, the laminated portion A (second substrate (thickness: 100 μm)/second adhesive layer (thickness: 5 μm)/isolation film) was obtained in the same manner as in Example 1.

[Implementation Example 5]

The thickness of the second adhesive layer was set to 25 μm. In addition, the laminated portion A (second substrate (thickness: 50 μm)/second adhesive layer (thickness: 25 μm)/isolation film) was obtained in the same manner as in Example 1.

[Implementation Example 6]

An adhesive solution was prepared by mixing 100 parts by weight of an acrylic copolymer (2-ethylhexyl acrylate:hydroxyethyl acrylate (weight ratio) = 100:4), 2 parts by weight of an isocyanate crosslinking agent (manufactured by Nippon Polyurethane Industry, trade name "CORONATE L"), 0.05 parts by weight of a crosslinking accelerator (manufactured by Tosoh Co., Ltd., trade name "Triethylenediamine (TEDA)"), and toluene. The above adhesive solution was applied to the PET film (50 μm) as the second substrate in a manner such that the thickness after drying was 10 μm and dried to form the second adhesive layer, and the PET separator film (38 μm) was attached to the second adhesive layer to obtain the laminated portion A (second substrate (thickness: 50 μm)/second adhesive layer (thickness: 10 μm)/separator film).

[Implementation Example 7]

An adhesive solution was prepared by mixing 100 parts by weight of an acrylic copolymer (butyl acrylate: acrylic acid (weight ratio) = 100:5), 2 parts by weight of an isocyanate crosslinking agent (manufactured by Nippon Polyurethane Industry, trade name "CORONATE L"), 0.5 parts by weight of an epoxy crosslinking agent (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name "TETRAD C"), and toluene. The above adhesive solution is applied to the PET film (50 μm) as the second substrate and dried to a thickness of 50 μm to form a second adhesive layer, and a PET separator film (38 μm) is attached to the second adhesive layer to obtain a laminated portion A (second substrate (thickness: 50 μm)/second adhesive layer (thickness: 50 μm)/separator film).

[Implementation Example 8]

An adhesive solution was prepared by mixing 100 parts by weight of an acrylic copolymer (2-ethylhexyl acrylate: acrylic acid = 95 parts by weight: 5 parts by weight), 5 parts by weight of an epoxy crosslinking agent (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name "TETRAD C"), and toluene. The adhesive solution was applied to a PET film (50 μm) as the second substrate so that the thickness after drying became 5 μm and dried to form a second adhesive layer. A PET separator film (38 μm) was attached to the second adhesive layer to obtain a laminated portion A (second substrate (thickness: 50 μm)/second adhesive layer (thickness: 5 μm)/separator film).

[Implementation Example 9]

An adhesive solution was prepared by mixing 100 parts by weight of an acrylic copolymer (2-ethylhexyl acrylate: acrylic acid = 95 parts by weight: 5 parts by weight), 3 parts by weight of an epoxy crosslinking agent (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name "TETRAD C"), and toluene. The adhesive solution was applied to a PET film (5μm) as a second substrate so that the thickness after drying became 3μm and dried to form a second adhesive layer. A PET separator film (38μm) was attached to the second adhesive layer to obtain a laminated portion A (second substrate (thickness: 5μm)/second adhesive layer (thickness: 3μm)/separator film).

[Example 10]

An adhesive solution was prepared by mixing 100 parts by weight of an acrylic copolymer (2-ethylhexyl acrylate: acrylic acid = 95 parts by weight: 5 parts by weight), 0.6 parts by weight of an epoxy crosslinking agent (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name "TETRAD C"), and toluene. The adhesive solution was applied to a PET film (50 μm) as the second substrate so that the thickness after drying became 10 μm and dried to form a second adhesive layer. A PET separator film (38 μm) was attached to the second adhesive layer to obtain a laminated portion A (second substrate (thickness: 50 μm)/second adhesive layer (thickness: 10 μm)/separator film).

[Implementation Example 11]

The thickness of the second adhesive layer was set to 50 μm. In addition, the laminated portion A (second substrate (thickness: 50 μm)/second adhesive layer (thickness: 50 μm)/isolation film) was obtained in the same manner as in Example 10.

[Implementation Example 12]

An adhesive solution was prepared by mixing 100 parts by weight of an acrylic copolymer (2-ethylhexyl acrylate: acrylic acid = 95 parts by weight: 5 parts by weight), 6 parts by weight of an epoxy crosslinking agent (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name "TETRAD C"), and toluene. The adhesive solution was applied to a PET film (50 μm) as the second substrate so that the thickness after drying was 3 μm and dried to form a second adhesive layer. A PET separator film (38 μm) was attached to the second adhesive layer to obtain a laminated portion A (second substrate (thickness: 50 μm)/second adhesive layer (thickness: 3 μm)/separator film).

<Evaluation>

The laminated portion A prepared in the embodiment and the adhesive sheet including the laminated portion A and the heat-peelable adhesive tape were subjected to the following evaluation. The results are shown in Table 1.

In addition, an adhesive sheet consisting only of a heat-peel adhesive tape without the laminate portion A was subjected to (4) evaluation of the protective properties of the heat-peel adhesive tape, and the result was used as the result of Comparative Example 1.

(1) Normal adhesion of laminated part A (second substrate/second adhesive layer)

The laminated portion A (second substrate/second adhesive layer) prepared in the embodiment was cut into a size of 20 mm in width and 140 mm in length. After the isolation film was peeled off, a polyethylene terephthalate film (trade name "Lumirror S-10" manufactured by Toray Co., Ltd.; thickness: 50 μm, width: 20 mm) as an adherend was bonded to the second adhesive layer in accordance with JIS Z 0237 (2000) (specifically, the films were bonded by pressing and returning a 2 kg roller once in an environment of temperature: 23±2°C and humidity: 65±5%RH) to prepare evaluation samples. The evaluation sample was mounted on a tensile testing machine (manufactured by Shimadzu Corporation, trade name "Shimadzu Autograph AG-120kN") with a constant temperature chamber set at 23°C and left for 30 minutes. After leaving, the load when the adherend was peeled off from the laminated part A at a peeling angle of 180° and a peeling speed (tensile speed) of 300mm/min at a temperature of 23°C was measured, and the average concave and convex load at this time was calculated (the average concave and convex load excluding the peak at the initial stage was measured), and the average concave and convex load was taken as the adhesion of the laminated part A (N/20mm width).

(2) Adhesion of the laminated part A (second substrate/second adhesive layer) after heating

Prepare samples for evaluation in the same manner as in (1) above.

The evaluation sample was heated at 100°C for 30 minutes, and then placed in a 23°C environment for 30 minutes. After that, the evaluation sample was mounted on a tensile testing machine (trade name "Shimadzu Autograph AG-120kN", manufactured by Shimadzu Corporation) with a constant temperature chamber set at 23°C and placed for 30 minutes. After placing, the load when the adherend is peeled off from the laminated part A at a peeling angle of 180° and a peeling speed (tensile speed) of 300mm/min at a temperature of 23°C was measured, and the average concave and convex load at this time (the average concave and convex load excluding the peak at the initial stage of the measurement) was calculated, and the average concave and convex load was used as the adhesion of the laminated part A (N/20mm width).

Based on the measured values, the releasability of the laminated part A is evaluated according to the following criteria. Furthermore, the releasability here is equivalent to the releasability of the adhesive sheet composed of the heat-peelable adhesive tape and the laminated part A being provided to the roll-to-roll process and being subjected to the friction with the conveyor roller, etc., which causes the temperature to rise.

○: Adhesion after heating is less than 5.0N/20mm

△: Adhesion after heating exceeds 5.0N/20mm

(3) Gel fraction of the second adhesive layer

About 0.1 g of the adhesive layer constituting the laminated part A was sampled and accurately weighed (the weight of the sample), and the sample was wrapped with a mesh sheet (trade name "NTF-1122", manufactured by Nitto Denko Co., Ltd.), and immersed in about 50 ml of toluene at room temperature for 1 week. Then, the solvent-insoluble components (contents of the mesh sheet) were taken out of the toluene, dried at 70°C for about 2 hours, and the solvent-insoluble components after drying were weighed (weight after immersion and drying), and the gel fraction (weight %) was calculated by the following formula (a).

Gel fraction (weight %) = [(weight after immersion and drying)/(weight of sample)] × 100 (a)

(4) Evaluation of the protective properties of heat-peel adhesive tapes

Using a hand roller, the laminated portion A prepared in the embodiment was adhered to the first substrate surface of a heat-peelable adhesive tape composed of a first substrate (PET film, thickness: 50 μm), an intermediate layer and a first adhesive layer to obtain an adhesive sheet for evaluation (first adhesive layer (heat-peelable)/intermediate layer/first substrate/second adhesive layer/second substrate). The heat-peelable adhesive tape was prepared by the method shown below.

30 parts by weight of terpene phenol adhesive resin (trade name "YS Polystar T80", manufactured by YASUHARA CHEMICAL) and 1 part by weight of isocyanate crosslinking agent (trade name "CORONATE L", manufactured by Nippon Polyurethane Industry) were mixed with 100 parts by weight of acrylic copolymer (butyl acrylate: hydroxyethyl acrylate = 100 parts by weight: 3 parts by weight), toluene was added, and the mixture was uniformly mixed to prepare an adhesive solution. The adhesive solution was applied to a PET substrate (first substrate, thickness: 50 μm) in such a way that the thickness after drying was 20 μm to form an intermediate layer.

Furthermore, 1 part by weight of an isocyanate crosslinking agent (trade name "CORONATE L", manufactured by Nippon Polyurethane Industry Co., Ltd.), 50 parts by weight of a foaming agent (thermal expansion microspheres; trade name "Matsumoto Microsphere F-30D", manufactured by Matsumoto Oil & Pharmaceutical Co., Ltd.), and toluene are uniformly mixed and dissolved in 100 parts by weight of the above copolymer, and the obtained coating liquid is applied to a PET base material separator film (38 μm) in a manner such that the thickness after drying becomes 30 μm to form the first adhesive layer. The adhesive layer is transferred to the above intermediate layer to obtain the above thermal release adhesive tape.

The probe adhesion of the first adhesive layer of the evaluation sample was measured under the following conditions, and the value was set as C ₀ . In addition, the back side (second substrate) of the evaluation sample was heated under the following conditions, and the probe adhesion C after heating was measured. The probe adhesion residual rate was calculated by the formula (C/C ₀ )×100.

When the heat from the back side causes the thermally expandable microspheres to start to foam, the probe adhesion value becomes smaller, and the probe adhesion residual rate also becomes smaller. Therefore, based on the probe adhesion residual rate, the protectiveness of the heat-peelable adhesive tape in the adhesive sheet is evaluated according to the following criteria.

○: The probe adhesion residual rate is more than 80%

△: The probe adhesion residual rate is above 70% and below 80%

×: The probe adhesion residual rate does not reach 70%

Furthermore, in the comparative example, the heat-peelable adhesive tape prepared as described above was directly used as the evaluation adhesive tape for the above evaluation.

‧Heating method

Place the second substrate (the first substrate in the comparative example) on a heating plate heated to 90°C so that it is on the heating plate side, and then place a glass weight (140mm×140mm×10mm) on top of the evaluation adhesive tape so that the tape evenly contacts the heating plate. Maintain this state for 20 seconds and heat the evaluation adhesive tape.

‧Probe adhesion measurement method

The probe adhesion was evaluated under the following conditions using an adhesion tester TAC-II (manufactured by RHESCA). The peak load (gf) applied when pulling out was taken as the probe adhesion value.

‧Metal probe diameter 10mm

‧Probe insertion speed 30mm/min

‧Loading capacity 50gf

‧Insert time: 0.5 seconds

‧Pull-out speed 30mm/min

(5) Stability evaluation of layer part A

Make the evaluation adhesive tape in the same way as (4) above.

Cut the evaluation adhesive tape into a size of 20mm×100mm. Bend the short strip of evaluation adhesive tape in half in the length direction with the laminated part A side becoming the inner side, and then stretch it to its original state.

By visually observing the folds, the evaluation was conducted according to the following criteria.

○: No bulge was observed between the first substrate surface of the thermal release adhesive tape and the second adhesive layer surface of the laminated portion A.

△: A partial bulge was observed between the first substrate surface and the second adhesive layer, but it is practically acceptable.

×: A bulge of a degree that is not practically acceptable was observed between the first substrate surface and the second adhesive layer.

10: Heat-peel adhesive tape

11: 1st adhesive layer

12: 1st base material

20: Layered part A

21: Second adhesive layer

22: Second base material

100: Adhesive sheet

Claims (7)

An adhesive sheet comprises, in order: a first adhesive layer, a first substrate, a second adhesive layer and a second substrate, wherein the first adhesive layer and the first substrate constitute a heat-peelable adhesive tape, the second adhesive layer and the second substrate constitute a laminated portion A, the laminated portion A is configured to be peelable from the heat-peelable adhesive tape, the laminated portion A has a thickness of 10 μm or more, the second adhesive layer has a thickness of 1 μm to 100 μm, the second substrate has a thickness of 8 μm to 400 μm, and the second adhesive layer is an acrylic adhesive. As in the adhesive sheet of claim 1, the thickness of the first adhesive layer is 1μm~30μm. As in claim 1, the adhesive sheet, wherein the elastic modulus of the first adhesive layer obtained by nanoindentation at 25°C is less than 100 MPa. As in the adhesive sheet of claim 1, the gel fraction of the second adhesive layer is 20% to 100% by weight. As in the adhesive sheet of claim 1, the adhesive force A2 of the laminated portion A to the polyethylene terephthalate film after being heated at 100°C for 30 minutes is less than 10 times the normal adhesive force A1 of the laminated portion A to the polyethylene terephthalate film. As in the adhesive sheet of claim 1, the normal adhesion force A1 of the above-mentioned laminated portion A to the polyethylene terephthalate film is 0.05N/20mm~5N/20mm. A method for conveying a heat-peelable adhesive tape having a first substrate and a first adhesive layer, and the conveying method includes: laminating a laminated portion A on the first substrate side, conveying the heat-peelable adhesive tape with the laminated portion A, wherein the laminated portion A has a second adhesive layer and a second substrate, the laminated portion A has a thickness of more than 10 μm, the second adhesive layer has a thickness of 1 μm to 100 μm, the second substrate has a thickness of 8 μm to 400 μm, and the second adhesive layer is an acrylic adhesive.