JP7133355B2 - Adhesive sheet - Google Patents

Description

The present invention relates to an adhesive sheet.

As an adhesive tape used for the purpose of temporarily fixing workpieces in the process of manufacturing electronic parts, etc., it exhibits adhesiveness during temporary fixing, and exhibits peelability when heated when fixing is not required. An easily peelable adhesive tape is known (for example, Patent Document 1). Such adhesive tapes usually comprise a substrate and an adhesive layer provided on the substrate. Further, in the production of the adhesive tape, after forming a laminate by laminating the base material and the adhesive layer, the laminate may be subjected to an inspection step and an adhesive layer processing step. . In such a process, a so-called roll-to-roll process, in which the long laminate is transported by transport rolls, is often adopted. At this time, frictional heat is generated due to contact with a transport roll or the like, and the properties of the pressure-sensitive adhesive layer may deteriorate.

Japanese Patent Application Laid-Open No. 2001-131507

The present invention has been made to solve the above-described conventional problems, and an object of the present invention is to provide a pressure-sensitive adhesive sheet comprising a heat-peelable pressure-sensitive adhesive tape comprising a substrate and a pressure-sensitive adhesive layer, wherein the pressure-sensitive adhesive layer is To provide a pressure-sensitive adhesive sheet which is hardly affected by heat applied from the substrate side and whose pressure-sensitive adhesive layer is hardly deteriorated even when subjected to a roll-to-roll process.

The pressure-sensitive adhesive sheet of the present invention comprises a first pressure-sensitive adhesive layer, a first substrate, a second pressure-sensitive adhesive layer, and a second substrate in this order, the first pressure-sensitive adhesive layer, The first base material constitutes a heat-peelable pressure-sensitive adhesive tape, the second pressure-sensitive adhesive layer and the second base material constitute a laminated portion A, and the laminated portion A constitutes the heat-releasable adhesive tape. It is arranged so that it can be peeled off from the peelable adhesive tape.
In one embodiment, the thickness of the laminated portion A is 10 μm or more.
In one embodiment, the second adhesive layer has a gel fraction of 20% to 100% by weight.
In one embodiment, the adhesive strength A2 to the polyethylene terephthalate film after heating the laminated portion A at 100° C. for 30 minutes is 10 times or less the normal adhesive strength A1 of the laminated portion A to the polyethylene terephthalate film. is.
In one embodiment, the normal state adhesive strength A1 of the laminated portion A to the polyethylene terephthalate film is 0.05 N/20 mm to 5 N/20 mm.
According to another aspect of the present invention, a method for conveying a heat-releasable adhesive tape is provided. This conveying method is a method for conveying a heat-peelable pressure-sensitive adhesive tape comprising a first base material and a first pressure-sensitive adhesive layer, wherein the laminated portion A is laminated on the first base material side, Including conveying the heat-releasable adhesive tape with part A.

According to the present invention, there is provided a pressure-sensitive adhesive sheet comprising a heat-peelable pressure-sensitive adhesive tape comprising a base material and a pressure-sensitive adhesive layer, wherein the pressure-sensitive adhesive layer is less susceptible to the heat applied from the base material side, and the roll-to-roll process It is possible to provide a pressure-sensitive adhesive sheet in which the pressure-sensitive adhesive layer is difficult to deteriorate even when subjected to

1 is a schematic cross-sectional view of an adhesive sheet according to one embodiment of the present invention; FIG.

A. Overall Configuration of Adhesive Sheet FIG. 1 is a schematic sectional view of an adhesive sheet according to one embodiment of the present invention. The adhesive sheet 100 includes a first adhesive layer 11, a first base material 12, a second adhesive layer 21, and a second base material 22 in this order. The first pressure-sensitive adhesive layer 11 and the first base material 12 constitute the heat-peelable pressure-sensitive adhesive tape 10 . The second pressure-sensitive adhesive layer 21 and the second base material 22 constitute the laminated portion A20. The laminated portion A20 is arranged so as to be peelable from the heat-peelable pressure-sensitive adhesive tape 10 . Although not shown, the adhesive sheet may further include any other suitable layers.

In the present invention, by providing the laminated portion A20 on the first base material 12 side of the thermally peelable adhesive tape 10, the heat applied from the first base material 12 side (substantially, the laminated portion A20 side) , the first adhesive layer 11 can be protected. More specifically, in situations where the heat-peelable adhesive tape 10 needs to be subjected to a roll-to-roll process (e.g., inspection of the adhesive layer surface, processing of the adhesive layer surface, etc.), the heat-peelable adhesive tape 10 is used. , The thermal peelable adhesive tape 10 (that is, the adhesive sheet 100) with the laminated portion A20 arranged on the first base material 12 side is subjected to the process, so that the temperature rise due to the influence of friction with the transport roll can protect the first pressure-sensitive adhesive layer 11 from the When the thermally peelable adhesive tape 10 is completed through a predetermined process, the laminated portion A20 is peeled off, and the thermally peelable adhesive tape 10 can be used, for example, as a temporary fixing tape in the electronic component manufacturing process. According to the present invention, by providing the laminated portion A20 that is laminated in a detachable manner, thermal deterioration of the adhesive layer (that is, the first adhesive layer) of the heat-peelable adhesive tape 10 is prevented, and heat The peelable pressure-sensitive adhesive tape 10 can have an appropriate thickness according to the actual application. The heat-peelable adhesive tape 10 may be stored as the heat-peelable adhesive tape 10 with the laminated portion A20 (that is, the adhesive sheet 100) until it is used.

In one embodiment, the pressure-sensitive adhesive sheet is provided in a long shape.

B. Thermally Releasable Adhesive Tape A thermally releasable adhesive tape is characterized in that its adhesive strength decreases or disappears when heated. The form of such a heat-peelable pressure-sensitive adhesive tape is not particularly limited, and examples thereof include a tape having a pressure-sensitive adhesive layer containing heat-expandable microspheres, a tape having a heat-curable pressure-sensitive adhesive layer, and the like. For example, when the heat-peelable adhesive tape is used as a sheet for temporarily fixing a workpiece during processing of an electronic component (for example, a ceramic capacitor), it is necessary for temporary fixing when the workpiece is subjected to a predetermined processing. When the heat-peelable pressure-sensitive adhesive tape is peeled from the processed product after processing, the adhesive strength is reduced or lost by heating, resulting in good peelability. In one embodiment, the heat-peelable pressure-sensitive adhesive tape comprises a base (first base) and a pressure-sensitive adhesive layer (first pressure-sensitive adhesive layer) containing the pressure-sensitive adhesive A and thermally expandable microspheres. Prepare. As a representative example of the heat-peelable pressure-sensitive adhesive tape, a heat-peelable pressure-sensitive adhesive tape having a first pressure-sensitive adhesive layer containing heat-expandable microspheres will be described below.

The heat-expandable microspheres in the first pressure-sensitive adhesive layer can expand at a predetermined temperature. In the pressure-sensitive adhesive layer containing such heat-expandable microspheres, the heat-expandable microspheres are foamed by heating, resulting in irregularities on the pressure-sensitive adhesive surface (that is, the surface of the first pressure-sensitive adhesive layer), and the adhesive strength is reduced. or disappear.

The adhesive strength (before heating) of the heat-releasable adhesive tape to a polyethylene terephthalate film (for example, thickness 25 μm) is preferably 0.1 N/20 mm or more, more preferably 1.0 N/20 mm to 50 N/20 mm. Yes, more preferably 2.0 N/20 mm to 20 N/20 mm. Within such a range, for example, it is possible to obtain a heat-peelable pressure-sensitive adhesive tape that is useful as a temporary fixing sheet used in the manufacture of electronic components. In this specification, the adhesive force is measured in an environment of 23° C. by a method according to JIS Z 0237:2000 (bonding conditions: 1 reciprocation of a 2 kg roller, peeling speed: 300 mm/min, peeling angle of 180°). Adhesive force.

The adhesive surface of the heat-peelable adhesive tape is adhered to a polyethylene terephthalate film, and the adhesive strength after heating is preferably 0.2 N/20 mm or less, more preferably 0.1 N/20 mm or less. As used herein, heating the heat-peelable pressure-sensitive adhesive tape means heating at a temperature and time at which the heat-expandable microspheres are expanded or foamed to reduce the adhesive force. The heating is, for example, heating at 70° C. to 270° C. for 1 minute to 10 minutes.

The thickness of the heat peelable adhesive tape is preferably 30 μm to 500 μm, more preferably 40 μm to 300 μm.

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, still more preferably 1 μm to 10 μm. Within such a range, it is possible to obtain a heat-peelable pressure-sensitive adhesive tape that can prevent displacement of the adherend and sinking into the first pressure-sensitive adhesive layer. The thickness of each layer constituting the adhesive sheet can be measured using a ruler, vernier caliper, or micrometer. Microscopes such as electron microscopes, optical microscopes, and atomic force microscopes may also be used. Furthermore, the thickness of each layer may be measured by determining the interface between adjacent layers based on the difference in composition. As a method for determining the interface, for example, spectroscopic analysis such as Raman spectroscopic analysis, infrared spectroscopic analysis, X-ray electron spectroscopic analysis; Methods such as mass spectrometry such as mass spectrometry (TOF-SIMS) can be mentioned.

The elastic modulus of the first pressure-sensitive adhesive layer measured by the nanoindentation method at 25° C. is preferably less than 100 MPa, more preferably 0.1 MPa to 50 MPa, still more preferably 0.1 MPa to 10 MPa. Within such a range, it is possible to obtain a heat-peelable pressure-sensitive adhesive tape that can prevent displacement of the adherend and sinking into the first pressure-sensitive adhesive layer. The elastic modulus by the nanoindentation method is obtained by continuously measuring the load applied to the indenter and the indentation depth during loading and unloading when the indenter is pushed into the sample (for example, the adhesive surface). It refers to the elastic modulus obtained from the applied load-indentation depth curve. As used herein, the elastic modulus by the nanoindentation method refers to the elastic modulus measured as described above under the measurement conditions of load: 1 mN, loading/unloading rate: 0.1 mN/s, and holding time: 1 s. When the first pressure-sensitive adhesive layer contains heat-expandable microspheres, the elastic modulus of the first pressure-sensitive adhesive layer measured by the nanoindentation method is obtained by selecting a portion where the heat-expandable microspheres are not present and measuring by the above method. is the elastic modulus measured by

(Adhesive A)
Any appropriate pressure-sensitive adhesive can be used as the pressure-sensitive adhesive A constituting the first pressure-sensitive adhesive layer as long as the effects of the present invention can be obtained. In one embodiment, as the adhesive A, a curable adhesive is used, preferably an active energy ray-curable adhesive is used. In another embodiment, a pressure-sensitive adhesive is used as the adhesive A. Examples of pressure-sensitive adhesives include acrylic adhesives and rubber adhesives.

(Active energy ray-curable adhesive)
Examples of the resin material constituting the active energy ray-curable pressure-sensitive adhesive include, for example, an ultraviolet curing system (written by Kiyomi Kato, published by Sogo Gijutsu Center, (1989)), a photo-curing technology (edited by Technical Information Association (2000)), Examples thereof include resin materials described in JP-A-2003-292916, JP-A-4151850, and the like. More specifically, a resin material (R1) containing a base polymer and an active energy ray-reactive compound (monomer or oligomer), a resin material (R2) containing an active energy ray-reactive polymer, and the like can be mentioned.

Examples of the base polymer include natural rubber, polyisobutylene rubber, styrene/butadiene rubber, styrene/isoprene/styrene block copolymer rubber, recycled rubber, butyl rubber, polyisobutylene rubber, nitrile rubber (NBR), and the like. rubber-based polymer; silicone-based polymer; acrylic-based polymer, and the like. These polymers may be used alone or in combination of two or more.

Examples of the active energy ray-reactive compound include photoreactive monomers or oligomers having a plurality of functional groups having carbon-carbon multiple bonds, such as acryloyl groups, methacryloyl groups, vinyl groups, allyl groups, and acetylene groups. . Among them, a compound having an ethylenically unsaturated functional group is preferably used, and a (meth)acrylic compound having an ethylenically unsaturated functional group is more preferably used. A compound having an ethylenically unsaturated functional group readily generates radicals upon exposure to ultraviolet rays, and thus the use of such a compound enables the formation of a first pressure-sensitive adhesive layer that can be cured in a short period of time. In addition, if a (meth)acrylic compound having an ethylenically unsaturated functional group is used, a pressure-sensitive adhesive having an appropriate hardness after curing (specifically, a hardness at which the thermally expandable microspheres can be well foamed). Layers can be formed. Specific examples of photoreactive monomers or oligomers include trimethylolpropane tri(meth)acrylate, tetramethylolmethane tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, and 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, urethane (meth)acryloyl group-containing compounds such as (meth)acrylate compounds; dimers to pentamers of the (meth)acryloyl group-containing compounds; and the like. These compounds may be used alone or in combination of two or more.

As the active energy ray-reactive compound, monomers such as epoxidized butadiene, glycidyl methacrylate, acrylamide, and vinylsiloxane; or oligomers composed of these monomers may 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 active energy ray-reactive compound, a mixture of an organic salt such as an onium salt and a compound having a plurality of heterocycles in the molecule may be used. When the mixture is irradiated with an active energy ray (e.g., ultraviolet rays, electron beams), the organic salt is cleaved to generate ions, which act as starting species to cause a heterocyclic ring-opening reaction to form a three-dimensional network structure. can. Examples of the organic salts include iodonium salts, phosphonium salts, antimonium salts, sulfonium salts, borate salts and the like. Examples of the heterocyclic ring in the compound having a plurality of heterocyclic rings in the molecule include oxirane, oxetane, oxolane, thiirane, aziridine and the like.

In the resin material (R1) containing the polymer serving as the base material and the active energy ray-reactive compound, the content of the active energy ray-reactive compound is preferably 0.1 to 100 parts by weight per 100 parts by weight of the polymer serving as the base material. It is 1 to 500 parts by weight, more preferably 1 to 300 parts by weight, still more preferably 10 to 200 parts by weight.

Examples of the active energy ray-reactive polymer include polymers having active energy ray-reactive functional groups having carbon-carbon multiple bonds, such as acryloyl groups, methacryloyl groups, vinyl groups, allyl groups, and acetylene groups. A compound (polymer) having an ethylenically unsaturated functional group is preferably used, and a (meth)acrylic polymer having an acryloyl group or a methacryloyl group is more preferably used. Specific examples of polymers having active energy ray-reactive functional groups include polymers composed of polyfunctional (meth)acrylates.

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

The active energy ray-curable pressure-sensitive adhesive can be cured by irradiation with an active energy ray. In the heat-peelable pressure-sensitive adhesive tape, the adherend is adhered to the adherend before curing the pressure-sensitive adhesive A, and then the adherend is adhered by irradiating the active energy ray to cure the pressure-sensitive adhesive A. can be done. Examples of active energy rays include gamma rays, ultraviolet rays, visible rays, infrared rays (heat rays), radio waves, alpha rays, beta rays, electron beams, plasma currents, ionizing rays, and particle beams. Conditions such as the wavelength and irradiation dose of the active energy ray can be set to any appropriate conditions depending on the type of resin material used. For example, the pressure-sensitive adhesive A can be cured by irradiating ultraviolet rays at an irradiation dose of 10 to 1000 mJ/cm ² .

(Acrylic adhesive)
Examples of the acrylic pressure-sensitive adhesive include, for example, an acrylic pressure-sensitive adhesive whose base polymer is an acrylic polymer (homopolymer or copolymer) using one or more of (meth)acrylic acid alkyl esters as a monomer component. etc. Specific examples of (meth) acrylic acid alkyl esters include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, (meth) ) isobutyl 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, isooctyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, (meth)acrylic acid Undecyl, dodecyl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, octadecyl (meth)acrylate , C1-20 alkyl (meth)acrylates such as nonadecyl (meth)acrylate and eicosyl (meth)acrylate. Among them, (meth)acrylic acid alkyl esters having a linear or branched alkyl group with 4 to 18 carbon atoms are preferably used.

For the purpose of modifying cohesive strength, heat resistance, crosslinkability, etc., the acrylic polymer may optionally be a unit corresponding to another monomer component copolymerizable with the (meth)acrylic acid alkyl ester. may contain Examples of such monomer components include carboxyl group-containing monomers such as acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid; maleic anhydride, itaconic anhydride; Acid anhydride monomers such as; hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, hydroxyhexyl (meth)acrylate, hydroxyoctyl (meth)acrylate, (meth)acrylate Hydroxyl group-containing monomers such as hydroxydecyl acrylate, hydroxyllauryl (meth)acrylate, (4-hydroxymethylcyclohexyl)methyl methacrylate; styrenesulfonic acid, allylsulfonic acid, 2-(meth)acrylamido-2-methylpropanesulfonic acid , (meth)acrylamidopropanesulfonic acid, sulfopropyl (meth)acrylate, (meth)acryloyloxynaphthalenesulfonic acid and other sulfonic acid group-containing monomers; (meth)acrylamide, N,N-dimethyl (meth)acrylamide, N-butyl (N-substituted) amide-based monomers such as (meth)acrylamide, N-methylol (meth)acrylamide, N-methylolpropane (meth)acrylamide; aminoethyl (meth)acrylate, N,N-dimethyl (meth)acrylate Aminoalkyl (meth)acrylate monomers such as aminoethyl and t-butylaminoethyl (meth)acrylate; Alkoxyalkyl (meth)acrylates such as methoxyethyl (meth)acrylate and ethoxyethyl (meth)acrylate Monomers: Maleimide monomers such as N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, N-phenylmaleimide; N-methylitaconimide, N-ethylitaconimide, N-butylitaconimide, N-octylitaconimide , N-2-ethylhexyl itaconimide, N-cyclohexyl itaconimide, N-lauryl itaconimide and other itaconimide monomers; N-(meth)acryloyloxymethylenesuccinimide, N-(meth)acryloyl-6-oxyhexamethylenesuccinimide, Succinimide-based monomers such as N-(meth)acryloyl-8-oxyoctamethylenesuccinimide; vinyl acetate, vinyl propionate, N-vinylpyrrolidone, methylvinylpyrrolidone Vinyls such as lydone, vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazole, vinyloxazole, vinylmorpholine, N-vinylcarboxylic acid amides, styrene, α-methylstyrene, N-vinylcaprolactam, etc. cyanoacrylate monomers such as acrylonitrile and methacrylonitrile; epoxy group-containing acrylic monomers such as glycidyl (meth)acrylate; polyethylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate, (meth)acrylic acid Glycol-based acrylic ester monomers such as methoxyethylene glycol and methoxypolypropylene glycol (meth)acrylate; heterocycles such as tetrahydrofurfuryl (meth)acrylate, fluorine (meth)acrylate, and silicone (meth)acrylate, halogen atoms, silicon atoms Acrylic acid ester-based monomers having, etc.; hexanediol di(meth)acrylate, (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol Polyfunctional monomers such as di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, epoxy acrylate, polyester acrylate, urethane acrylate; isoprene, butadiene, Olefin monomers such as isobutylene; vinyl ether monomers such as vinyl ether; These monomer components may be used alone or in combination of two or more.

(rubber adhesive)
Examples of the rubber-based adhesive include 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 Polymer (SEP) rubber, recycled rubber, butyl rubber, polyisobutylene, synthetic rubber such as modified products thereof;

(Additive)
The pressure-sensitive adhesive A may contain any appropriate additive as necessary. Examples of such additives include initiators, cross-linking agents, tackifiers, plasticizers, pigments, dyes, fillers, anti-aging agents, conductive materials, antistatic agents, ultraviolet absorbers, light stabilizers, and release modifiers. , softeners, surfactants, flame retardants, antioxidants, and the like.

(Heat-expandable microspheres)
In one embodiment, the first pressure-sensitive adhesive layer contains heat-expandable microspheres. In the first pressure-sensitive adhesive layer containing heat-expandable microspheres, the heat-expandable microspheres expand or foam when heated, resulting in irregularities on the pressure-sensitive adhesive surface and reduced or lost adhesive strength. By using the heat-peelable pressure-sensitive adhesive tape having such a first pressure-sensitive adhesive layer as a temporary fixing material, it is possible to easily separate the adherend after temporary fixing.

Any appropriate heat-expandable microspheres can be used as the heat-expandable microspheres as long as they can be expanded or foamed by heating. As the heat-expandable microspheres, for example, microspheres in which a substance that easily expands by heating is encapsulated in an elastic shell can be used. Such heat-expandable microspheres can be produced by any appropriate method such as coacervation, interfacial polymerization, and the like.

Substances that easily expand when heated include, for example, propane, propylene, butene, normal butane, isobutane, isopentane, neopentane, normal pentane, normal hexane, isohexane, heptane, octane, petroleum ether, methane halides, and tetraalkylsilanes. low boiling point liquid such as; azodicarbonamide gasified by thermal decomposition; and the like.

Examples of substances constituting the shell include nitrile monomers such as acrylonitrile, methacrylonitrile, α-chloroacrylonitrile, α-ethoxyacrylonitrile, and fumaronitrile; acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, Carboxylic acid monomers such as citraconic acid; vinylidene chloride; vinyl acetate; methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, (Meth)acrylic acid esters such as isobornyl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, β-carboxyethyl acrylate; styrene monomers such as styrene, α-methylstyrene, chlorostyrene; acrylamide, substituted acrylamide , methacrylamide, substituted methacrylamide, and other amide monomers; A 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, acrylonitrile-methacrylonitrile-itaconic acid copolymer, A polymer etc. are mentioned.

An inorganic foaming agent or an organic foaming agent may be used as the thermally expandable microspheres. Examples of inorganic foaming agents include ammonium carbonate, ammonium hydrogencarbonate, sodium hydrogencarbonate, ammonium nitrite, sodium borohydride, and various azides. Examples of organic foaming agents include chlorofluoroalkane compounds such as trichloromonofluoromethane and dichloromonofluoromethane; and azo compounds such as azobisisobutyronitrile, azodicarbonamide, and barium azodicarboxylate. hydrazine compounds such as paratoluenesulfonyl hydrazide, diphenylsulfone-3,3′-disulfonyl hydrazide, 4,4′-oxybis(benzenesulfonyl hydrazide), and allylbis(sulfonyl hydrazide); p-toluylenesulfonyl semicarbazide, 4, Semicarbazide compounds such as 4'-oxybis(benzenesulfonyl semicarbazide); triazole compounds such as 5-morpholyl-1,2,3,4-thiatriazole; N,N'-dinitrosopentamethylenetetramine, N,N' -dimethyl-N,N'-dinitrosoterephthalamide; and other N-nitroso compounds.

Commercially available products may be used as the heat-expandable microspheres. Specific examples of commercially available heat-expandable microspheres include Matsumoto Yushi Seiyaku's trade name "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), a product name manufactured by Nippon Philite Co., Ltd. " Expancel” (Grade: 053-40, 031-40, 920-40, 909-80, 930-120), Kureha Chemical Industry Co., Ltd. “Daiform” (Grade: H750, H850, H1100, S2320D, S2640D, M330, M430, M520), "Advancel" manufactured by Sekisui Chemical Co., Ltd. (grades: EML101, EMH204, EHM301, EHM302, EHM303, EM304, EHM401, EM403, EM501).

The particle size of the heat-expandable microspheres before heating is preferably 0.5 μm to 80 μm, more preferably 5 μm to 45 μm, even more preferably 10 μm to 20 μm, and particularly preferably 10 μm to 15 μm. . Therefore, the average particle size of the heat-expandable microspheres before heating is preferably 6 μm to 45 μm, more preferably 15 μm to 35 μm. The above particle size and average particle size are values determined by a particle size distribution measurement method in a laser scattering method.

It is preferable that the heat-expandable microspheres have an appropriate strength such that they do not explode until the volume expansion coefficient reaches preferably 5 times or more, more preferably 7 times or more, and still more preferably 10 times or more. When such heat-expandable microspheres are used, the adhesive strength can be efficiently reduced by heat treatment.

The content of the heat-expandable microspheres in the first pressure-sensitive adhesive layer can be appropriately set according to the desired reduction in adhesive strength. The content 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, more preferably 100 parts by weight of the base polymer forming the first pressure-sensitive adhesive layer. 25 to 100 parts by weight.

B-2. First base material Examples of the first base material include resin sheets, nonwoven fabrics, paper, metal foils, woven fabrics, rubber sheets, foam sheets, laminates thereof (especially laminates containing resin sheets), and the like. is mentioned. 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 (aramid), polyimide (PI), polyvinyl chloride (PVC), polyphenylene sulfide (PPS), fluorine resin, polyether ether ketone (PEEK) ) and the like. Examples of nonwoven fabrics include nonwoven fabrics made of heat-resistant natural fibers such as nonwoven fabrics containing manila hemp; synthetic resin nonwoven fabrics such as polypropylene resin nonwoven fabrics, polyethylene resin nonwoven fabrics and ester resin nonwoven fabrics.

The thickness of the first base material can be set to any appropriate thickness depending on desired strength or flexibility, purpose of use, and the like. The thickness of the substrate is preferably 1000 μm or less, more preferably 1 μm to 1000 μm, still more preferably 1 μm to 500 μm, particularly preferably 3 μm to 300 μm, most preferably 5 μm to 250 μm.

The first base material may be surface-treated. Examples of surface treatment include corona treatment, chromic acid treatment, ozone exposure, flame exposure, high voltage shock exposure, ionizing radiation treatment, and coating treatment with a primer. By performing such a surface treatment, the adhesion between the first pressure-sensitive adhesive layer and the substrate can be enhanced. In particular, coating treatment with an organic coating material is preferable because it enhances adhesion and makes it difficult for the first pressure-sensitive adhesive layer to break due to anchoring during peeling. The surface treatment layer may be formed on the surface facing the first pressure-sensitive adhesive layer.

Examples of the organic coating material include materials described in Plastic Hard Coat Materials II (CMC Publishing, (2004)). Urethane-based polymers are preferably used, more preferably polyacrylurethane, polyesterurethane, or precursors thereof. This is because coating and applying to the base material is simple, and industrially, a wide variety of materials can be selected and are available at low cost. The urethane-based polymer is, for example, a polymer composed of a reaction mixture of an isocyanate monomer and an alcoholic hydroxyl group-containing monomer (for example, a hydroxyl group-containing acrylic compound or a hydroxyl group-containing ester compound). The organic coating material may contain optional additives such as chain extenders such as polyamines, anti-aging agents, oxidation stabilizers, and the like. The thickness of the organic coating layer is not particularly limited. The organic coating layer can be formed, for example, using any suitable printing method or the like using the above organic coating material.

B-3. Intermediate Layer The heat-peelable pressure-sensitive adhesive tape may further comprise an intermediate layer between the first pressure-sensitive adhesive layer and the first substrate. Examples of materials constituting the intermediate layer include silicone-based polymers, epoxy-based polymers, polycarbonate-based polymers, vinyl-based polymers, acrylic-based polymers, urethane-based polymers, polyester-based polymers, polyolefin-based polymers, polyamide-based polymers, and polyimide-based polymers. Examples include polymer materials such as polymers and unsaturated hydrocarbon-based polymers. When these polymer materials are used, the intermediate layer having the above elastic modulus can be easily formed by appropriately selecting the type of monomer, cross-linking agent, degree of polymerization, and the like. The above polymer materials may 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 the material forming the 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 intermediate layer with appropriate timing, and the elastic modulus can be easily adjusted. If the intermediate layer is formed of such a material, it has low elasticity, high flexibility, and excellent handleability when the adhesive sheet is attached. A controllable adhesive sheet can be obtained.

Examples of the resin material that can be cured by irradiation with an active energy ray include a resin material (R1) containing a polymer that serves as a base material and an active energy ray-reactive compound (monomer or oligomer) described in section B-1 above; A resin material (R2) containing an active energy ray-reactive polymer and the like are included. In one embodiment, a compound having an ethylenically unsaturated functional group can be used as the active energy ray-reactive compound in the resin material (R1) used as the material for the intermediate layer. In one embodiment, a compound (polymer) having an ethylenically unsaturated functional group can be used as the active energy ray-reactive polymer in the resin material (R2).

Further, as a material for forming the intermediate layer, a hot-melt resin composed of a thermoplastic resin such as an ethylene-vinyl acetate copolymer, a polypropylene resin, or a polyamide resin may be used.

The intermediate layer may further contain any appropriate additive as needed. Examples of such additives include initiators, cross-linking agents, tackifiers, plasticizers, pigments, dyes, fillers, anti-aging agents, conductive materials, antistatic agents, ultraviolet absorbers, light stabilizers, and release modifiers. , softeners, surfactants, flame retardants, antioxidants, and the like.

The thickness of the intermediate layer is preferably 1 μm to 200 μm, more preferably 5 μm to 50 μm, still more preferably 10 μm to 40 μm.

C. Laminated part A
As noted above, Laminated Part A comprises a second adhesive layer and a second substrate. The adhesive layer usually has lower thermal conductivity than the substrate. In the present invention, the laminated portion A containing such an adhesive layer (second adhesive layer) protects the heat-peelable adhesive tape, so that the first adhesive layer (the heat-peelable adhesive tape has The adhesive layer) is prevented from thermally deteriorating.

The adhesive strength A1 (normal adhesive strength A1) of the laminated portion A to a polyethylene terephthalate film (eg, thickness 50 μm) is preferably 0.04 N/20 mm to 10 N/20 mm, more preferably 0.05 N/20 mm to 5 N/20 mm, more preferably 0.08 N/20 mm to 4.5 N/20 mm, still more preferably 0.1 N/20 mm to 2.5 N/20 mm, particularly preferably 0.15 N/20 mm to 1 .2N/20mm. Within such a range, when the pressure-sensitive adhesive sheet (that is, the laminate of the heat-peelable adhesive tape and the laminate portion A) is subjected to a predetermined process, the laminate portion A is not easily peeled off from the heat-peelable adhesive tape. In addition, it is possible to obtain a pressure-sensitive adhesive sheet from which the unnecessary laminated portion A can be easily peeled off from the heat-peelable pressure-sensitive adhesive tape after a predetermined process.

The adhesive strength A2 (post-heating adhesive strength A2) to a polyethylene terephthalate film (for example, a thickness of 50 μm) after heating the laminated portion A at 100° C. for 30 minutes is preferably 0.05 N/20 mm to 10.0 N/20 mm. , more preferably 0.08 N/20 mm to 5.0 N/20 mm, still more preferably 0.10 N/20 mm to 1.5 N/20 mm. Within such a range, the laminated portion A can have a desired peel strength even if the temperature of the adhesive sheet rises when the adhesive sheet is subjected to a predetermined process. The adhesive strength after heating is the adhesive strength in an environment of 23°C when the temperature of the second adhesive layer is lowered to 23°C after heating at the above temperature.

The post-heating adhesive strength A2 is preferably 10 times or less, more preferably 5 times or less, and further preferably 0.001 to 2.5 times the normal state adhesive strength A1. 0.001-fold to 1.8-fold is particularly preferred. Within such a range, the laminated portion A can have a desired peel strength even if the temperature of the adhesive sheet rises when the adhesive sheet is subjected to a predetermined process.

The thickness of the laminated portion A is preferably 10 μm or more, more preferably 20 μm or more, still more preferably 30 μm or more, particularly preferably 50 μm to 500 μm, most preferably 50 μm to 300 μm. When the thickness of the laminated portion A is 10 μm or more, thermal deterioration of the first pressure-sensitive adhesive layer can be significantly prevented.

C-1. Second Adhesive Layer The thickness of the second adhesive layer is preferably 1 μm to 100 μm, more preferably 5 μm to 80 μm, still more preferably 5 μm to 50 μm. Within such a range, thermal deterioration of the first pressure-sensitive adhesive layer can be significantly prevented.

The second pressure-sensitive adhesive layer typically contains a pressure-sensitive adhesive B having a predetermined polymer as a base polymer. As the adhesive B, a pressure-sensitive adhesive is preferably used. 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-based adhesives, styrene-diene block copolymer-based adhesives, and the like can be mentioned. Acrylic pressure-sensitive adhesives or silicone pressure-sensitive adhesives are particularly preferable. In addition, you may use the said adhesive individually or in combination of 2 or more types.

As the acrylic pressure-sensitive adhesive contained in the second pressure-sensitive adhesive layer, for example, the pressure-sensitive adhesive described in section B-1 above is used.

Any appropriate pressure-sensitive adhesive can be used as the silicone-based pressure-sensitive adhesive contained in the second pressure-sensitive adhesive layer. As the silicone-based pressure-sensitive adhesive, for example, a silicone-based pressure-sensitive adhesive having a base polymer such as silicone rubber containing organopolysiloxane or silicone resin is preferably used. A base polymer obtained by cross-linking the above silicone rubber or silicone resin may be used as the base polymer constituting the silicone pressure-sensitive adhesive. In this specification, the distinction between "silicone rubber" and "silicone resin" is defined in "Technical Information Association Adhesive (film/tape) material design and functionalization, 1st edition, September 30, 2009, 222- 228”. That is, the term "silicone rubber" means straight-chain silicone composed of diorganosiloxane (D unit), and the silicone rubber has a viscosity of, for example, about 10000 Pa·s. "Silicone resin" means a silicone containing triorganosilhemioxane (M unit) and silicate (Q unit) and having a branched structure.

The gel fraction of the second pressure-sensitive adhesive layer is preferably 20% to 100% by weight, more preferably 30% to 99% by weight, still more preferably 50% to 99% by weight. . Within such a range, the increase in adhesive strength after heating is suppressed, and the laminated portion A having excellent releasability can be formed. A gel fraction is measured as follows.
<Gel fraction measurement method>
About 0.1 g of the second adhesive layer was sampled and precisely weighed (weight of the sample), and the sample was wrapped in a mesh sheet (trade name “NTF-1122”, manufactured by Nitto Denko Co., Ltd.). It was immersed in 50 ml of toluene at room temperature for one week. After that, the solvent-insoluble matter (contents of the mesh sheet) was taken out from the toluene and dried at 70° C. for about 2 hours, and the solvent-insoluble matter after drying was weighed (weight after immersion and drying), and the following formula (a) was obtained. Calculate the gel fraction (% by weight).
Gel fraction (% by weight) = [(Weight after immersion and drying) / (Weight of sample)] × 100 (a)

The base polymer constituting the pressure-sensitive adhesive B preferably has an OH group or a COOH group. This is because the use of such a base polymer makes it possible to adjust the gel fraction using a cross-linking agent.

C-2. Second base material Examples of the second base material include resin sheets, nonwoven fabrics, paper, metal foils, woven fabrics, rubber sheets, foam sheets, laminates thereof (especially laminates containing resin sheets), and the like. is mentioned. A resin sheet is preferable. 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 (aramid), polyimide (PI), polyvinyl chloride (PVC), polyphenylene sulfide (PPS), fluorine resin, polyether ether ketone (PEEK) ) and the like. Among them, PET or PI is preferred.

The thickness of the second substrate is preferably 8 μm to 400 μm, more preferably 15 μm to 300 μm, particularly preferably 25 μm to 200 μm. Within such a range, thermal deterioration of the first pressure-sensitive adhesive layer can be significantly prevented.

The second base material may be surface-treated. The surface treatment includes, for example, the treatment described in section B-2 above. The surface treatment layer may be formed on the surface facing the second pressure-sensitive adhesive layer.

D. Production method of pressure-sensitive adhesive sheet The pressure-sensitive adhesive sheet of the present invention can be produced by any appropriate method. In one embodiment, after forming the heat-peelable pressure-sensitive adhesive tape, a second pressure-sensitive adhesive layer is placed on the opposite side of the first base material of the heat-peelable pressure-sensitive adhesive tape from the first pressure-sensitive adhesive layer. The pressure-sensitive adhesive sheet can be manufactured by laminating the laminated portion A so as to laminate the second base material with the pressure-sensitive adhesive sheet.

The heat-peelable pressure-sensitive adhesive tape can be produced by any appropriate method. The heat-peelable pressure-sensitive adhesive tape includes, for example, the pressure-sensitive adhesive A that forms the first pressure-sensitive adhesive layer directly on the first substrate (the first pressure-sensitive adhesive layer containing thermally expandable microspheres is In some cases, a method of applying the pressure-sensitive adhesive layer-forming composition A, which further contains heat-expandable microspheres), or a method of applying the pressure-sensitive adhesive layer-forming composition A on any appropriate substrate. and a method of transferring the coated layer to the first substrate. The pressure-sensitive adhesive layer-forming composition A may contain any appropriate solvent. In the case of forming the first pressure-sensitive adhesive layer containing heat-expandable microspheres, after forming the pressure-sensitive adhesive coating layer with a composition containing the pressure-sensitive adhesive A, the pressure-sensitive adhesive coating layer is heat-expandable. After sprinkling the microspheres, the heat-expandable microspheres may be embedded in the coating layer using a laminator or the like to form a first pressure-sensitive adhesive layer containing the heat-expandable microspheres.

The content of the thermally expandable microspheres in the pressure-sensitive adhesive layer-forming composition A is preferably 5% by weight to 95% by weight, more preferably 10% to 70% by weight, more preferably 10% to 50% by weight.

The laminated portion A can be manufactured by any appropriate method. The laminated portion A is, for example, a method of directly applying a pressure-sensitive adhesive layer-forming composition B containing a pressure-sensitive adhesive B that forms a second pressure-sensitive adhesive layer on the second substrate, or any appropriate method. a method of applying the pressure-sensitive adhesive layer-forming composition B on a substrate and transferring the formed coating layer to a second substrate. The pressure-sensitive adhesive layer-forming composition B may contain any appropriate solvent.

Any appropriate coating method may be employed as a method for coating each of the above compositions. For example, each layer can be formed by coating and then drying. Examples of the coating method include coating methods using a multi-coater, die coater, gravure coater, applicator, and the like. Drying methods include, for example, natural drying and heat drying. The heating temperature for drying by heating can be set to any suitable temperature depending on the properties of the substance to be dried.

E. Method for Conveying Heat-Peelable Adhesive Tape The method for conveying a heat-peelable adhesive tape of the present invention is a method for conveying the above-mentioned heat-peelable adhesive tape, comprising a first base material and a first pressure-sensitive adhesive layer. Laminating a laminated portion A on the first substrate side of the thermally peelable adhesive tape and conveying the thermally peelable adhesive tape with the laminated portion A. Laminated part A includes a second adhesive layer and a second substrate, as described above. Laminated part A is arranged by laminating a second base material via a second adhesive layer on the side opposite to the first adhesive layer of the first base material of the heat-peelable adhesive tape. be done.

In one embodiment, the conveying method includes conveying a heat-peelable adhesive tape (substantially a heat-peelable adhesive tape with a laminated portion A) using a conveying roll. The heat-peelable pressure-sensitive adhesive tape with the laminated portion A is preferably conveyed with the laminated portion A on the conveying roll side. According to the conveying method of the present invention, by conveying the heat-peelable adhesive tape using the laminated portion A, the first adhesive layer can be protected from the temperature rise due to the influence of friction with the conveying roll. can. According to the present invention, by providing the laminated portion A20 that is releasably laminated, deterioration of the adhesive layer (that is, the first adhesive layer) of the heat-peelable adhesive tape is prevented, and the heat-peelable The adhesive tape can have an appropriate thickness depending on the actual application.

EXAMPLES The present invention will be specifically described below with reference to Examples, but the present invention is not limited to these Examples. Evaluation methods in the examples are as follows. In the examples, "parts" and "%" are by weight unless otherwise specified.

[Example 1]
100 parts by weight of an acrylic copolymer (2-ethylhexyl acrylate: acrylic acid = 95 parts by weight: 5 parts by weight); Toluene was mixed to prepare an adhesive solution. A PET film (thickness: 50 μm) as a second substrate is coated with the adhesive solution so that the thickness after drying is 5 μm and dried to form a second adhesive layer. A PET separator (thickness: 38 μm) is laminated on the adhesive layer, and the laminated portion A (second base material (thickness: 50 μm) / second adhesive layer (thickness: 5 μm) / separator) got

[Example 2]
Laminated portion A (second substrate) was prepared in the same manner as in Example 1, except that a polyimide film (thickness: 50 μm) was used as the second substrate instead of the PET film (thickness: 50 μm). A material (thickness: 50 μm)/second adhesive layer (thickness: 5 μm)/separator) was obtained.

[Example 3]
Laminated portion A (second substrate) was prepared in the same manner as in Example 1, except that a PET film (thickness: 25 μm) was used as the second substrate instead of the PET film (thickness: 50 μm). A material (thickness: 25 μm)/second adhesive layer (thickness: 5 μm)/separator) was obtained.

[Example 4]
Laminated portion A (second substrate) was prepared in the same manner as in Example 1, except that a PET film (thickness: 100 μm) was used as the second substrate instead of the PET film (thickness: 50 μm). A material (thickness: 100 μm)/second adhesive layer (thickness: 5 μm)/separator) was obtained.

[Example 5]
Laminated portion A (second substrate (thickness: 50 μm)/second adhesive layer (thickness: 25 μm)/separator).

[Example 6]
100 parts by weight of an acrylic copolymer (2-ethylhexyl acrylate: hydroxyethyl acrylate (weight ratio) = 100:4) and 2 parts by weight of an isocyanate-based cross-linking agent (manufactured by Nippon Polyurethane Co., Ltd., trade name "Coronate L") , 0.05 parts by weight of a cross-linking accelerator (manufactured by Tosoh Corporation, trade name "triethylenediamine (TEDA)") and toluene were mixed to prepare an adhesive solution. The adhesive solution is applied to a PET film (50 μm) as a second base material so that the thickness after drying is 10 μm, and dried to form a second adhesive layer. A PET separator (38 μm) was laminated on the adhesive layer to obtain a laminated portion A (second base material (thickness: 50 μm)/second adhesive layer (thickness: 10 μm)/separator).

[Example 7]
100 parts by weight of an acrylic copolymer (butyl acrylate:acrylic acid (weight ratio) = 100:5), 2 parts by weight of an isocyanate-based cross-linking agent (manufactured by Nippon Polyurethane Co., Ltd., trade name "Coronate L"), and an epoxy A pressure-sensitive adhesive solution was prepared by mixing 0.5 parts by weight of a cross-linking agent (manufactured by Mitsubishi Gas Chemical Company, trade name "Tetrad C") and toluene. A PET film (50 μm) as a second substrate is coated with the adhesive solution so that the thickness after drying is 50 μm and dried to form a second adhesive layer. A PET separator (38 μm) was laminated on the layer to obtain a laminated portion A (second base material (thickness: 50 μm)/second adhesive layer (thickness: 50 μm)/separator).

[Example 8]
100 parts by weight of an acrylic copolymer (2-ethylhexyl acrylate: acrylic acid = 95 parts by weight: 5 parts by weight); Toluene was mixed to prepare an adhesive solution. A PET film (50 μm) as a second substrate is coated with the adhesive solution so that the thickness after drying is 5 μm and dried to form a second adhesive layer. A PET separator (38 μm) was laminated on the layer to obtain a laminated portion A (second base material (thickness: 50 μm)/second adhesive layer (thickness: 5 μm)/separator).

[Example 9]
100 parts by weight of an acrylic copolymer (2-ethylhexyl acrylate: acrylic acid = 95 parts by weight: 5 parts by weight); Toluene was mixed to prepare an adhesive solution. A PET film (5 μm) as a second substrate is coated with the adhesive solution so that the thickness after drying is 3 μm and dried to form a second adhesive layer. A PET separator (38 μm) was laminated on the layer to obtain a laminated portion A (second base material (thickness: 5 μm)/second adhesive layer (thickness: 3 μm)/separator).

[Example 10]
100 parts by weight of an acrylic copolymer (2-ethylhexyl acrylate: acrylic acid = 95 parts by weight: 5 parts by weight) and 0.6 parts by weight of an epoxy-based cross-linking agent (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name "Tetrad C") and toluene to prepare an adhesive solution. A PET film (50 μm) as a second substrate is coated with the adhesive solution so that the thickness after drying is 10 μm and dried to form a second adhesive layer. A PET separator (38 μm) was laminated on the layer to obtain a laminated portion A (second base material (thickness: 50 μm)/second adhesive layer (thickness: 10 μm)/separator).

[Example 11]
Laminated portion A (second substrate (thickness: 50 μm) / second adhesive layer (thickness : 50 μm)/separator).

[Example 12]
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-based cross-linking agent (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name "Tetrad C"), Toluene was mixed to prepare an adhesive solution. A PET film (50 μm) as a second substrate is coated with the adhesive solution so that the thickness after drying is 3 μm and dried to form a second adhesive layer. A PET separator (38 μm) was laminated on the layer to obtain a laminated portion A (second base material (thickness: 50 μm)/second adhesive layer (thickness: 3 μm)/separator).

<Evaluation>
Laminated part A prepared in Examples and an adhesive sheet comprising laminated part A and a heat-peelable adhesive tape were subjected to the following evaluations. Table 1 shows the results.
In addition, the pressure-sensitive adhesive sheet, which does not include the laminated portion A and is composed only of the heat-peelable pressure-sensitive adhesive tape, was subjected to (4) evaluation of the protective properties of the heat-peelable pressure-sensitive adhesive tape.
(1) Normal state adhesive strength of laminated portion A (second substrate/second adhesive layer) Laminated portion A (second substrate/second adhesive layer) prepared in Example has a width of 20 mm , length: cut to a size of 140 mm, after peeling off the separator, polyethylene terephthalate film as an adherend (trade name "Lumirror S-10" manufactured by Toray Industries, Inc. on the second adhesive layer; thickness: 50 μm, width: 20 mm) are laminated according to JIS Z 0237 (2000) (specifically, in an atmosphere of temperature: 23 ± 2 ° C. and humidity: 65 ± 5% RH, a 2 kg roller is applied. It was made to reciprocate once and pressed against each other to bond) to prepare an evaluation sample. This evaluation sample was set in a tensile tester with a constant temperature bath set at 23° C. (manufactured by Shimadzu Corporation, trade name “Shimadzu Autograph AG-120 kN”) and left for 30 minutes. After standing, at a temperature of 23 ° C., the adherend was peeled off from the laminated portion A under the conditions of a peeling angle of 180° and a peeling speed (tensile speed) of 300 mm/min. The average unevenness load (the average unevenness load of the load excluding the peak top at the initial stage of measurement) was determined, and this average unevenness load was defined as the adhesive strength of the laminated portion A (N/20 mm width).

(2) Post-heating Adhesive Strength of Laminated Portion A (Second Base Material/Second Adhesive Layer) An evaluation sample was prepared in the same manner as in (1) above.
The evaluation sample was heated at 100° C. for 30 minutes and then left in an atmosphere of 23° C. for 30 minutes. After that, the evaluation sample was set in a tensile tester with a constant temperature bath set at 23° C. (trade name “Shimadzu Autograph AG-120 kN” manufactured by Shimadzu Corporation) and allowed to stand for 30 minutes. After standing, at a temperature of 23 ° C., the adherend was peeled off from the laminated portion A under the conditions of a peeling angle of 180° and a peeling speed (tensile speed) of 300 mm/min. The average unevenness load (the average unevenness load of the load excluding the peak top at the initial stage of measurement) was determined, and this average unevenness load was defined as the adhesive strength of the laminated portion A (N/20 mm width).
Also, based on the measured values, the peelability of the laminated portion A was evaluated according to the following criteria. In addition, the peelability here is due to the influence of friction with the transport roll when the adhesive sheet composed of the heat-peelable adhesive tape and the laminated portion A is subjected to a roll-to-roll process in the actual use scene. It can correspond to the peelability after being subjected to a temperature rise.
○: Adhesive strength after heating is 5.0 N / 20 mm or less △: Adhesive strength after heating exceeds 5.0 N / 20 mm

(3) Gel fraction of the second pressure-sensitive adhesive layer About 0.1 g of the pressure-sensitive adhesive layer constituting the laminated portion A was sampled and accurately weighed (weight of the sample), and the sample was transferred to a mesh sheet (trade name: NTF -1122", manufactured by Nitto Denko Corporation), and then immersed in about 50 ml of toluene at room temperature for 1 week. After that, the solvent-insoluble matter (contents of the mesh sheet) was taken out from the toluene and dried at 70° C. for about 2 hours, and the solvent-insoluble matter after drying was weighed (weight after immersion and drying), and the following formula (a) was obtained. A gel fraction (% by weight) was calculated.
Gel fraction (% by weight) = [(Weight after immersion and drying) / (Weight of sample)] × 100 (a)

(4) Evaluation of protective properties of heat-releasable adhesive tape Laminated portion A prepared in Examples is composed of a first base material (PET film, thickness: 50 μm), an intermediate layer, and a first adhesive layer. A hand roller is used to laminate the first base material surface of the heat-peelable adhesive tape, and an evaluation adhesive sheet (first adhesive layer (heat-releasable) / intermediate layer / first base material / first 2 adhesive layers/second substrate) were obtained. The heat-peelable pressure-sensitive adhesive tape was produced by the method shown below.
100 parts by weight of an acrylic copolymer (butyl acrylate: hydroxyethyl acrylate = 100 parts by weight: 3 parts by weight), and 30 parts by weight of a terpene phenol-based tackifying resin (trade name "YS Polyster T80", manufactured by Yasuhara Chemical Co., Ltd.) , An isocyanate-based cross-linking agent (trade name "Coronate L", manufactured by Nippon Polyurethane Co., Ltd.) 1 part by weight was added, and toluene was added to prepare a pressure-sensitive adhesive solution that was uniformly mixed, and the PET base material (first base material, Thickness: 50 μm), the adhesive solution was applied so as to have a thickness of 20 μm after drying to form an intermediate layer.
Further, to 100 parts by weight of the above copolymer, 1 part by weight of an isocyanate cross-linking agent (trade name "Coronate L", manufactured by Nippon Polyurethane Co., Ltd.), a blowing agent (thermally expandable microspheres; trade name "Matsumoto Microsphere F") -30D", manufactured by Matsumoto Yushi Seiyaku Co., Ltd.) 50 parts by weight, and toluene are uniformly mixed, and the dissolved coating liquid is coated on a PET base separator (38 μm) so that the thickness after drying is 30 μm. to form a first pressure-sensitive adhesive layer. This pressure-sensitive adhesive layer was transferred onto the intermediate layer to obtain the heat-peelable pressure-sensitive adhesive tape.

The probe tack adhesive strength of the first adhesive layer of the evaluation sample was measured under the following conditions, and the value was defined as _C0 . In addition, the sample for evaluation was heated from the back side (second substrate) side under the following conditions, and the probe tack adhesive strength C after heating was measured. The probe tack residual ratio was calculated by the formula (C/C ₀ )×100.
When thermally expandable microspheres start to foam under the influence of heat from the back surface, the probe tack value decreases, and the probe tack residual rate also decreases accordingly. Therefore, based on the magnitude of the probe tack residue rate, the protective property of the heat-peelable adhesive tape on the adhesive sheet was evaluated according to the following criteria.
○: Probe tack residue rate is 80% or more △: Probe tack residue rate is 70% or more and less than 80% ×: Probe tack residue rate is less than 70%

In Comparative Examples, the heat-peelable pressure-sensitive adhesive tape produced as described above was directly used as the pressure-sensitive adhesive tape for evaluation and subjected to the above evaluation.

- Heating method Place the second base material (the first base material in the comparative example) on the hot plate heated to 90 ° C. on the hot plate side, and further, from the adhesive tape for evaluation, A glass weight (140 mm x 140 mm x 10 mm) was placed so that the tape was evenly in contact with the hot plate. This state was maintained for 20 seconds to heat the adhesive tape for evaluation.
- Probe tack adhesive force measurement method Using a tack tester TAC-II (manufactured by RHESCA), the probe tack adhesive force was evaluated under the following conditions. The peak load (gf) applied at the time of drawing was taken as the probe tack value.
・Metal probe diameter 10mm
・Probe pushing speed 30mm/min
・Load 50gf
・Pressing time 0.5sec
・Pull-out speed 30mm/min

(5) Stability Evaluation of Laminated Portion A A pressure-sensitive adhesive tape for evaluation was prepared in the same manner as in (4) above.
The adhesive tape for evaluation was cut into a size of 20 mm×100 mm. A strip-shaped pressure-sensitive adhesive tape for evaluation was folded in half with respect to the longitudinal direction with the laminated portion A facing inward, and then stretched to its original state.
The crease portion was visually observed and evaluated according to the following criteria.
○: No float is confirmed between the first base material surface of the heat-peelable adhesive tape and the second adhesive layer surface of the laminated part A △: Between the first base material surface and the second adhesive layer Partial floating was confirmed between them, but it is practically acceptable. ×: Practically unacceptable floating is confirmed between the first base material surface and the second pressure-sensitive adhesive layer.

REFERENCE SIGNS LIST 10 heat peelable adhesive tape 11 first adhesive layer 12 first base material 20 laminated portion A
21 second adhesive layer 22 second base material 100 adhesive sheet

Claims (4)

A first adhesive layer, a first substrate, a second adhesive layer, and a second substrate are provided in this order,
The first pressure-sensitive adhesive layer and the first base constitute a heat-peelable pressure-sensitive adhesive tape,
The second adhesive layer and the second base material constitute a laminated portion A,
The laminated portion A is arranged so as to be peelable from the heat-peelable adhesive tape,
The thickness of the laminated portion A is 10 μm or more,
The adhesive strength A2 to the polyethylene terephthalate film after heating the laminated portion A at 100 ° C. for 30 minutes is 10 times or less than the normal adhesive strength A1 of the laminated portion A to the polyethylene terephthalate film,
wherein the second pressure-sensitive adhesive layer comprises an acrylic pressure-sensitive adhesive;
adhesive sheet. The pressure-sensitive adhesive sheet according to claim 1, wherein the second pressure-sensitive adhesive layer has a gel fraction of 20% to 100% by weight. 3. The pressure-sensitive adhesive sheet according to claim 1, wherein the normal-state adhesive strength A1 of said laminated portion A to a polyethylene terephthalate film is from 0.05 N/20 mm to 5 N/20 mm. A method for conveying a heat-peelable pressure-sensitive adhesive tape comprising a first substrate and a first pressure-sensitive adhesive layer,
Laminating the laminated portion A on the first substrate side and conveying the heat-peelable adhesive tape with the laminated portion A;
The laminated portion A includes a second adhesive layer and a second substrate,
The thickness of the laminated portion A is 10 μm or more ,
A method for conveying a heat-peelable adhesive tape.

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