KR20160103522A - Heat-peelable pressure-sensitive adhesive sheet - Google Patents

Abstract

The present invention relates to a heat-removable adhesive sheet provided with an adhesive layer highly resistant against infiltration of a liquid chemical. The heat-removable adhesive sheet comprises a first adhesive layer, a substrate and a second adhesive layer, successively, wherein the first adhesive layer comprises an acrylic adhesive containing a (meth)acrylic polymer and heat-expansible microspheres, and the (meth)acrylic polymer includes a structural unit derived from an alkyl (meth)acrylate containing an alkyl group having 2 or more carbon atoms and a structural unit derived from an OH-containing (meth)acrylic monomer. In the (meth)acrylic polymer, the molar ratio (C/OH) of carbon (C) to OH groups of the pendant alkyl groups is 40-150.

Description

HEAT-PEELABLE PRESSURE-SENSITIVE ADHESIVE SHEET [0002]

The present invention relates to a heat-peelable pressure-sensitive adhesive sheet.

BACKGROUND ART [0002] Conventionally, when a substrate provided in an electronic device is manufactured, an adhesive sheet is attached to a substrate material for protection (for example, Patent Document 1). For example, when etching a copper foil as a substrate material, an adhesive sheet is attached to the copper foil to prevent the etching solution from adhering to the non-processed surface of the copper foil. Further, even when the glass substrate is surface-polished with an acid such as hydrofluoric acid, the pressure-sensitive adhesive sheet adheres to the non-treated surface. In the case of the pressure-sensitive adhesive sheet for this purpose, when the chemical liquid enters the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet, the pressure-sensitive adhesive layer and the other layer interface, the intruded chemical liquid becomes a cause of outgassing in the subsequent process after the chemical liquid treatment, The material is deteriorated. For example, in a pressure-sensitive adhesive layer containing a thermally expandable microspheres (foaming agent) added for the purpose of re-releasability as described in Patent Document 1, the foaming agent chemically deteriorates by an acidic or alkaline chemical liquid Resulting in a problem that the foaming function is lost.

Japanese Patent Application Laid-Open No. 2001-019915

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned conventional problems, and its main object is to provide a heat peeling type pressure-sensitive adhesive sheet (heat-peelable pressure-sensitive adhesive sheet) comprising a pressure-

The heat-peelable pressure-sensitive adhesive sheet of the present invention comprises a first pressure-sensitive adhesive layer, a substrate, and a second pressure-sensitive adhesive layer in this order, wherein the first pressure-sensitive adhesive layer comprises an acrylic pressure-sensitive adhesive containing a (meth) Wherein the (meth) acryl-based polymer comprises a structural unit derived from a (meth) acrylic acid alkyl ester having an alkyl group having 2 or more carbon atoms and a structural unit derived from a (meth) acrylic monomer having an OH group, (C / OH) of the carbon (C) and OH groups of the side chain alkyl group in the (meth) acrylic polymer is 40 to 150.

In one embodiment, the second pressure-sensitive adhesive layer includes the thermally expandable microspheres.

In one embodiment, the center line average surface roughness (Ra) of the first pressure-sensitive adhesive layer and / or the second pressure-sensitive adhesive layer is 1 占 퐉 or less.

In one embodiment, the contact angle of water with respect to the first pressure-sensitive adhesive layer and / or the second pressure-sensitive adhesive layer is 85 ° to 115 °.

In one embodiment, the first pressure sensitive adhesive layer contains a tackifier, and the content of the tackifier is 40 parts by weight or less based on 100 parts by weight of the first pressure sensitive adhesive layer.

In one embodiment, the second pressure sensitive adhesive layer contains a tackifier, and the content of the tackifier is 40 parts by weight or less based on 100 parts by weight of the second pressure sensitive adhesive layer.

In one embodiment, the gel fraction of the first pressure-sensitive adhesive layer and / or the second pressure-sensitive adhesive layer is 50% or more.

In one embodiment, the adhesive force at 23 캜 when the first pressure-sensitive adhesive layer side is bonded to the polyethylene terephthalate film is 1 N / 20 mm or more.

According to another aspect of the present invention, an electronic component is provided. The electronic component is manufactured using the heat-peelable pressure-sensitive adhesive sheet.

In the present invention, it is preferred to use a (meth) acrylic polymer containing a constituent unit derived from a (meth) acrylic acid alkyl ester having an alkyl group having 2 or more carbon atoms and a (meth) acrylic monomer having an OH group as a base polymer By forming the pressure-sensitive adhesive layer and setting the molar ratio (C / OH) of the carbon (C) to the OH group (C / OH) of the side chain alkyl group in the (meth) acrylic polymer to a specific range, It is possible to provide a heat-peelable pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer. Further, since the pressure-sensitive adhesive sheet of the present invention is provided with the pressure-sensitive adhesive layer containing the thermally expandable microspheres, excellent releasability is exhibited by heating. Further, in the present invention, since the chemical solution is hardly penetrated into the pressure-sensitive adhesive layer, the function of the thermally expandable microspheres is not impaired even in applications where the chemical solution is exposed to an acidic or alkaline chemical solution (for example, , And a heat-peelable pressure-sensitive adhesive sheet in which stickiness and peelability are highly compatible can be provided.

1 is a schematic cross-sectional view of a heat-peelable pressure-sensitive adhesive sheet according to one embodiment of the present invention.
2 is a schematic cross-sectional view of a heat-peelable pressure-sensitive adhesive sheet according to another embodiment of the present invention.

A. Overall structure of heat-peelable pressure-sensitive adhesive sheet

1 is a schematic cross-sectional view of a heat-peelable pressure-sensitive adhesive sheet according to one embodiment of the present invention. The heat-peelable pressure-sensitive adhesive sheet 100 comprises a first pressure-sensitive adhesive layer 10, a substrate 20, and a second pressure-sensitive adhesive layer 30 in this order. The first pressure-sensitive adhesive layer (10) includes thermally expandable microspheres. Since the thermally expandable microspheres are expanded or foamed by heating, the pressure-sensitive adhesive layer containing the heat-expandable microspheres is deteriorated in adhesiveness by heating. The heat-peelable pressure-sensitive adhesive sheet of the present invention has a pressure-sensitive adhesive layer containing thermally expandable microspheres, so that even when an adherend is adhered to both surfaces, the adherend can be easily peeled off by heating, It is possible to prevent breakage. The thermally expandable microspheres may also be included in the second pressure sensitive adhesive layer.

2 is a schematic cross-sectional view of a heat-peelable pressure-sensitive adhesive sheet according to another embodiment of the present invention. The heat-peelable pressure-sensitive adhesive sheet (200) further comprises an elastic layer (40). The elastic layer 40 may be provided adjacent to the first pressure-sensitive adhesive layer 10 or the second pressure-sensitive adhesive layer 30. Preferably, the elastic layer 40 is provided adjacent to the pressure-sensitive adhesive layer including the thermally expandable microspheres. In one embodiment, it is provided between the first pressure-sensitive adhesive layer 10 and the substrate 20 as shown in the drawing. By providing the elastic layer, the followability to an adherend having an uneven surface is improved. Further, when the elastic layer is provided adjacent to the pressure-sensitive adhesive layer containing the thermally expandable microspheres, deformation (expansion) in the surface direction of the pressure-sensitive adhesive layer upon heating at the time of peeling is restrained, and deformation in the thickness direction is prioritized. As a result, the peelability is improved.

Although not shown, the heat-peelable pressure-sensitive adhesive sheet of the present invention may be provided with a release liner outside the pressure-sensitive adhesive layer for the purpose of protecting the pressure-sensitive adhesive surface during use.

When the first pressure sensitive adhesive layer side of the heat peelable pressure sensitive adhesive sheet of the present invention is bonded to a polyethylene terephthalate (PET) film, the adhesive force at 23 캜 is preferably 1 N / 20 mm or more, more preferably 3 N / 20 N / 20 mm, and more preferably 4 N / 20 mm to 10 N / 20 mm. In such a range, a useful heat-peelable pressure-sensitive adhesive sheet can be obtained as a pressure-sensitive adhesive sheet for temporary protection. In this specification, the adhesive force refers to the adhesive force measured by the method according to JIS Z 0237: 2000. A concrete measurement method will be described later. The heat-peelable pressure-sensitive adhesive sheet of the present invention is a pressure-sensitive adhesive sheet in which the adhesive force is lowered by heating. The above-mentioned "adhesive force at 23 ° C" refers to the adhesive force before the adhesive force is lowered.

B. First adhesive layer

The first pressure-sensitive adhesive layer includes an acrylic pressure-sensitive adhesive I comprising a (meth) acrylic polymer as a base polymer and thermally expandable microspheres.

B-1. Acrylic adhesive I

<(Meth) Acrylic Polymer>

As the (meth) acrylic polymer contained in the acrylic pressure-sensitive adhesive I, a polymer obtained by using, as a monomer component, a (meth) acrylic acid alkyl ester (a) having an alkyl group having 2 or more carbon atoms and (meth) Is used.

Specific examples of the (meth) acrylic acid alkyl ester (a) include (meth) acrylic acid ethyl, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) (meth) acrylate, isobutyl (meth) acrylate, isobutyl (meth) acrylate, isobutyl (meth) acrylate, (Meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, isodecyl (meth) acrylate, decyl (meth) acrylate, isodecyl (Meth) acrylate, octadecyl (meth) acrylate, octadecyl (meth) acrylate, eicosyl (meth) acrylate, . (Meth) acrylic acid alkyl ester (a) may be used singly or in combination of two or more kinds.

The number of carbon atoms of the alkyl group of the (meth) acrylic acid alkyl ester (a) is 2 or more, preferably 4 or more, more preferably 4 to 20, and still more preferably 6 to 18 as described above. By using the (meth) acrylic acid alkyl ester (a) having such an alkyl group, a pressure sensitive adhesive layer hardly penetrating a chemical liquid (for example, an acidic or alkaline chemical liquid) can be formed.

Specific examples of the (meth) acrylic monomer (b) having an OH group include (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, hydroxyhexyl (Meth) acrylate hydroxydecyl, (meth) acrylate hydroxydecyl, (meth) acrylate hydroxylauryl and (4-hydroxymethylcyclohexyl) methyl methacrylate. As the (meth) acrylic monomer (b), a carboxyl group-containing (meth) acrylic monomer such as acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid or crotonic acid may be used. The (meth) acrylic monomer (b) may be used singly or in combination of two or more kinds.

The (meth) acryl-based polymer contained in the acrylic pressure-sensitive adhesive I may be polymerized with the above-mentioned (meth) acrylic acid alkyl ester (a) and / or the (meth) acrylic monomer may contain a constituent unit corresponding to another monomer copolymerizable with the monomer (b). As such a monomer, for example, (meth) acrylate; Acid anhydride monomers such as maleic anhydride and itaconic anhydride; Sulfonic acid groups such as styrenesulfonic acid, allylsulfonic acid, 2- (meth) acrylamide-2-methylpropanesulfonic acid, (meth) acrylamidopropanesulfonic acid, sulfopropyl (meth) acrylate, and (meth) acryloyloxynaphthalenesulfonic acid Containing monomer; (Meth) acrylamide, N, N-dimethyl (meth) acrylamide, N-butyl (meth) acrylamide, N-methylol -Substituted) amide-based monomer; (Meth) acrylic acid aminoalkyl monomers such as aminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate and t-butylaminoethyl (meth) acrylate; (Meth) acrylic acid alkoxyalkyl monomers such as methoxyethyl (meth) acrylate and ethoxyethyl (meth) acrylate; Maleimide-based monomers such as N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide and N-phenylmaleimide; N-diisopropylethylenediamine, N-methylethylenediamine, N-methylethylenediamine, N-methylethylenediamine, N-methylethylenediamine, N-methylethylenediamine, Itaconimide-based monomers such as N, N-lauryl itaconimide; (Meth) acryloyloxymethylenesuccinimide, N- (meth) acryloyl-6-oxyhexamethylenesuccinimide, N- (meth) acryloyl-8- Succinimide monomer; Vinyl pyrrolidone, vinyl pyrrolidone, vinyl pyridine, vinyl piperidone, vinyl pyrimidine, vinylpiperazine, vinyl pyrazine, vinyl pyrrole, vinyl imidazole, vinyl oxazole, vinyl Vinyl monomers such as morpholine, N-vinylcarboxylic acid amides, styrene,? -Methylstyrene, and N-vinylcaprolactam; Cyanoacrylate monomers such as acrylonitrile and methacrylonitrile; An epoxy group-containing acrylic monomer such as glycidyl (meth) acrylate; Glycol type acrylic ester monomers such as (meth) acrylic acid polyethylene glycol, (meth) acrylic acid polypropylene glycol, (meth) acrylic acid methoxyethylene glycol and (meth) acrylic acid methoxypolypropylene glycol; Acrylate monomer having a heterocycle such as tetrahydrofurfuryl (meth) acrylate, fluorine (meth) acrylate or silicone (meth) acrylate, halogen atoms, silicon atoms and the like; (Meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, (poly) ethylene glycol di (Meth) acrylate, trimethylol propane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, epoxy acrylate, polyester acrylate, and urethane acrylate Monomers; Olefinic monomers such as isoprene, butadiene and isobutylene; And vinyl ether-based monomers such as vinyl ether. These monomer components may be used singly or in combination of two or more kinds.

The (meth) acrylic polymer contained in the acrylic pressure-sensitive adhesive I can be obtained by copolymerizing (meth) acrylic acid alkyl ester (a) having an alkyl group having 2 or more carbon atoms with (meth) acrylic monomer (b) And the other monomer (c) is polymerized by any suitable polymerization method. The (meth) acrylic polymer thus obtained is preferably a (meth) acrylic acid ester derived from a (meth) acrylic acid alkyl ester having an alkyl group having 2 or more carbon atoms (preferably 4 or more, more preferably 4 to 20, and still more preferably 6 to 18) A structural unit A, and a structural unit B derived from a (meth) acrylic monomer having an OH group. That is, the (meth) acrylic polymer includes a constituent unit A having an alkyl group having 2 or more carbon atoms in its side chain and a constituent unit B having an OH group.

The content of the (meth) acrylic polymer containing the constituent unit A and the constituent unit B is preferably 50 parts by weight to 100 parts by weight, more preferably 60 parts by weight, per 100 parts by weight of the solid content in the acrylic pressure- To 98 parts by weight, and more preferably 65 parts by weight to 90 parts by weight.

The content of the constituent unit A derived from the (meth) acrylic acid alkyl ester having an alkyl group having 2 or more carbon atoms is preferably 70 to 98 parts by weight based on 100 parts by weight of the (meth) acrylic polymer, Is 80 to 95 parts by weight, and more preferably 85 to 95 parts by weight.

The content of the constituent unit B derived from the (meth) acrylic monomer having an OH group is preferably 1 part by weight to 30 parts by weight, more preferably 2 parts by weight or less, based on 100 parts by weight of the (meth) 20 parts by weight, and more preferably 3 parts by weight to 10 parts by weight.

In the (meth) acryl-based polymer contained in the acrylic pressure-sensitive adhesive I, the molar ratio (C / OH) of the carbon (C) to the OH group of the side chain alkyl group is preferably 40 to 150, more preferably 42 to 120 , More preferably from 50 to 100, particularly preferably from 55 to 80, and most preferably from 55 to 75. The molar ratio (C / OH) is preferably in the range of from 0.1 to 10 parts by weight, more preferably from 1 to 100 parts by weight, based on the total amount of the monomers constituting the structural unit having a side-chain alkyl group (i.e., (meth) acrylic acid alkyl ester (a) Molecular weight and the number of OH groups of the (meth) acrylic monomer (b) having an OH group. For example, monomer a ₁ , monomer a ₂ and monomer a ₃ are used as the monomer forming the structural unit having a side chain alkyl group, and monomers b ₁ and b ₂ are used as the (meth) acrylic monomer (b) , The molar ratio (C / OH) can be obtained from the following formula (1).

In the present invention, by including a predetermined amount of an alkyl group having 2 or more carbon atoms in the (meth) acrylic polymer as the base polymer, the polarity of the pressure-sensitive adhesive layer is lowered to prevent the infiltration of a chemical solution (for example, acidic or alkaline chemical solution) can do. On the other hand, if the polarity of the pressure-sensitive adhesive layer is too low, sufficient adhesive force can not be obtained. In the present invention, the (meth) acrylic polymer further contains an OH group, and the molar ratio of the carbon (C) (C / OH) falls within the above-mentioned range, penetration of the chemical liquid into the pressure-sensitive adhesive layer can be prevented while maintaining adhesiveness. The heat-peelable pressure-sensitive adhesive sheet of the present invention comprising the pressure-sensitive adhesive layer capable of exhibiting excellent tackiness by containing a predetermined amount of OH groups can effectively prevent the penetration of the chemical solution into the interface between the pressure-sensitive adhesive sheet and the adherend. By preventing the penetration of the chemical liquid, the deterioration of the pressure-sensitive adhesive can be suppressed, so that excellent tackiness can be maintained. Further, deterioration of the thermally expansible microspheres in the pressure-sensitive adhesive layer by the chemical liquid can be suppressed, so that even when used in an acidic or alkaline chemical liquid, the heat peelability is not impaired. In addition, the pressure-sensitive adhesive composed of the (meth) acrylic polymer is difficult to inhibit expansion or foaming of the thermally expandable microspheres. The heat-peelable pressure-sensitive adhesive sheet exhibiting these effects can be suitably used as a protective sheet in a process using an acidic or alkaline chemical liquid, such as an etching treatment process.

The weight average molecular weight of the (meth) acrylic polymer (measured by gel permeation chromatography (solvent: THF) using a calibration curve of standard polystyrene) is preferably 100,000 to 3,000,000 in terms of polystyrene, More preferably from 200,000 to 250,000, and still more preferably from 300,000 to 2,000,000.

<Additives>

The acrylic pressure-sensitive adhesive I may contain any suitable additives, if necessary. Examples of the additives include crosslinking agents, tackifiers, plasticizers (e.g., trimellitic acid ester plasticizers, pyromellitic acid ester plasticizers), pigments, dyes, fillers, antioxidants, conductive materials, antistatic agents, ultraviolet Absorbents, light stabilizers, peel adjusters, softeners, surfactants, flame retardants, and antioxidants.

As the tackifier, any suitable tackifier is used. As the tackifier, for example, a tackifier resin is used. Specific examples of the tackifier resin include rosin-based tackifying resins (for example, unmodified rosin, modified rosin, rosin phenol-based resin, rosin ester-based resin and the like), terpene-based tackifying resins (for example, (For example, aliphatic hydrocarbon resins, aliphatic cyclic hydrocarbon resins, and aromatic hydrocarbon resins (for example, aliphatic hydrocarbon resin, aromatic hydrocarbon resin, or aromatic hydrocarbon resin), a terpene type phenolic resin, a terpene type phenolic resin, a styrene type modified terpene type resin, an aromatic modified terpene type resin, Aliphatic and alicyclic petroleum resins, aliphatic and alicyclic petroleum resins, hydrogenated hydrocarbon resins, coumarone resins, coumarone-indene resins and the like), phenolic tackifier resins (for example, styrene resins and xylene resins) For example, an alkylphenol resin, a xylene formaldehyde resin, a resole, a novolak, etc.), a ketone-based tackifying resin, a polyamide-based tackifying resin, an epoxy- Tackifying resins, and elastomer-based tackifying resins. Among them, rosin-based tackifying resin, terpene-based tackifying resin or hydrocarbon-based tackifying resin (styrene type resin, etc.) are preferable. The tackifiers may be used alone or in combination of two or more.

Commercially available products may be used as the tackifier. Specific examples of commercially available tackifiers include terpene phenol resins such as "YS Polystar S145" and "Mighty Ace K140" available from Yasuhara Chemical Co., Ltd. and "Tamanol 901" available from Arakawa Chemical Industries, Ltd.; Sumilite Resin PR-12603 &quot; manufactured by Sumitomo Bakelite Co., Ltd., rosin phenol resin such as &quot; Tamanol 361 &quot; Alkylphenol resins such as "Tamanol 1010R" and "Tamanol 200N" manufactured by Arakawa Chemical Industries, Ltd.; And alicyclic saturated hydrocarbon resins such as &quot; Alcon P-140 &quot;, trade name, manufactured by Arakawa Chemical Industries, Ltd., and the like.

The amount of the tackifier added is preferably 40 parts by weight or less, more preferably 30 parts by weight or less, further preferably 25 parts by weight or less, and even more preferably 15 parts by weight or less, with respect to 100 parts by weight of the pressure- Parts by weight to 25 parts by weight. In such a range, a pressure-sensitive adhesive layer excellent in adhesion and irregularity followability can be formed. When the pressure-sensitive adhesive layer excellent in irregularity followability is formed, penetration of the chemical solution between the pressure-sensitive adhesive layer and the adherend is remarkably prevented.

The hydroxyl value of the tackifier is preferably 10 mgKOH / g or more, and more preferably 40 mgKOH / g to 400 mgKOH / g. In such a range, stickiness and prevention of intrusion of a chemical solution are compatible, and the effect of the present invention becomes remarkable.

Examples of the cross-linking agent include, in addition to an isocyanate-based cross-linking agent, an epoxy-based cross-linking agent, a melamine-based cross-linking agent and a peroxide-based cross-linking agent, urea cross-linking agents, metal alkoxide cross-linking agents, metal chelate cross-linking agents, metal salt cross- Based crosslinking agents, aziridine-based crosslinking agents, and amine-based crosslinking agents. Among them, an isocyanate crosslinking agent or an epoxy crosslinking agent is preferable.

Specific examples of the isocyanate crosslinking agent include lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate; Cycloaliphatic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate and isophorone diisocyanate; Aromatic isocyanates such as 2,4-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate and xylylene diisocyanate; Trimethylolpropane / tolylene diisocyanate trimer adduct (trade name "Coronate L" manufactured by Nippon Polyurethane Industry Co., Ltd.), trimethylolpropane / hexamethylene diisocyanate trimer adduct (available from Nippon Polyurethane Industry Co., Ltd., Coronate HL , And isocyanurate compounds of hexamethylene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name &quot; Coronate HX &quot;). The content of the isocyanate-based crosslinking agent may be set to any suitable amount depending on the desired adhesive force, and is preferably from 0.1 part by weight to 100 parts by weight based on 100 parts by weight of the base polymer (i.e., (meth) acrylic polymer) in the acrylic pressure- 20 parts by weight, and more preferably 0.5 part by weight to 10 parts by weight.

Examples of the epoxy cross-linking agent include N, N, N ', N'-tetraglycidyl-m-xylenediamine, diglycidyl aniline, 1,3-bis (N, N-glycidylaminomethyl ), Cyclohexane (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name &quot; Tertor C &quot;, 1,6-hexanediol diglycidyl ether (manufactured by Kyowa Chemical Co., Ethylene glycol diglycidyl ether (trade name: "Epolite 40E" manufactured by Kyowa Chemical Co., Ltd.), propylene glycol diglycidyl ether (trade name: "Epolite 1500NP" EPOLOL E-400 &quot;), polypropylene glycol diglycidyl ether (manufactured by Nippon Oil Co., Ltd., trade name, manufactured by Nippon Oil Co., Ltd.) Epiol P-200 &quot;), sorbitol polyglycidyl ether (product of Nagase ChemteX, trade name &quot; Denacol EX-611 ), Glycerol polyglycidyl ether (trade name, "Denacol EX-314", product of Nagase ChemteX), pentaerythritol polyglycidyl ether, polyglycerol polyglycidyl ether EX-512 &quot;), sorbitan polyglycidyl ether, trimethylolpropane polyglycidyl ether, adipic diglycidyl ester, o-phthalic acid diglycidyl ester, triglycidyl-tris S-diglycidyl ether, an epoxy resin having two or more epoxy groups in the molecule, etc. The content of the epoxy cross-linking agent is, for example, May be set to any appropriate amount depending on the desired adhesive force, and is typically from 0.01 to 10 parts by weight, more preferably from 0.03 to 5 parts by weight, based on 100 parts by weight of the base polymer.

B-2. Thermally expandable microsphere

The thermally expandable micropores are micropores that can be expanded or foamed by heating. The heat-peelable pressure-sensitive adhesive sheet having the pressure-sensitive adhesive layer containing the heat-expandable microspheres has a sufficient adhesive force when the adhesive force is required because unevenness is generated on the adhesive surface by heating to decrease the adhesive force, The peeling property is excellent. As described above, in the present invention, even when exposed to an acidic or alkaline chemical liquid, the thermally expandable microspheres are less likely to be altered, and the above functions as thermally expandable microspheres can be sufficiently expressed.

The content of the thermally expandable microspheres can be appropriately set in accordance with the lowering of the desired adhesive force and the like. The content of the thermally 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, 1 part by weight to 100 parts by weight, relative to 100 parts by weight of the (meth) acrylic polymer in the acrylic pressure- 25 parts by weight to 100 parts by weight.

As the thermally expandable microspheres, any suitable thermally expandable microspheres can be used. As the thermally expandable microspheres, microspheres containing a substance which is easily swollen by heating, for example, in a shell having elasticity can be used. Such thermally expandable microspheres can be produced by any appropriate method, for example, a coacervation method, an interfacial polymerization method, or the like.

Examples of the substance that can be easily expanded by heating include a halogen such as propane, propylene, butene, normal butane, isobutane, isopentane, neopentane, n-pentane, n-hexane, isohexane, heptane, Low-boiling liquids such as cargo, tetraalkylsilane and the like; And azodicarbonamide which is gasified by pyrolysis.

Examples of the material constituting the shell include nitrile monomers such as acrylonitrile, methacrylonitrile,? -Chloracrylonitrile,? -Ethoxyacrylonitrile, and fumaronitrile; Carboxylic acid monomers such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid and citraconic acid; Vinylidene chloride; Vinyl acetate; (Meth) acrylate, isobornyl (meth) acrylate, isobornyl (meth) acrylate, isobutyl (meth) acrylate, (Meth) acrylic acid esters such as hexyl (meth) acrylate, benzyl (meth) acrylate and? -Carboxyethyl acrylate; Styrene monomers such as styrene,? -Methyl styrene and chlorostyrene; Amide monomers such as acrylamide, substituted acrylamide, methacrylamide, and substituted methacrylamide, and the like. The polymer composed of these monomers may be either 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, and the like.

As the thermally expandable microspheres, an inorganic foaming agent or an organic foaming agent may be used. Examples of the inorganic foaming agent include ammonium carbonate, ammonium hydrogencarbonate, sodium hydrogen carbonate, ammonium nitrite, sodium borohydride, and various azides. Examples of the organic foaming agent include chlorobenzene-based compounds such as trichloromonofluoromethane and dichloromonofluoromethane; Azo compounds such as azobisisobutyronitrile, azodicarbonamide, and barium azodicarboxylate; Hydrazine compounds such as para-toluenesulfonyl hydrazide, diphenylsulfone-3,3'-disulfonylhydrazide, 4,4'-oxybis (benzenesulfonylhydrazide) and allyl bis (sulfonylhydrazide); a semicarbazide-based compound such as p-toluenesulfonyl semicarbazide, 4,4'-oxybis (benzenesulfonyl semicarbazide); Triazole-based compounds such as 5-morpholyl-1,2,3,4-thiatriazole; N-nitroso compounds such as N, N'-dinitrosopentamethylenetetramine and N, N'-dimethyl-N, N'-dinitrosoterephthalamide.

A commercially available product may be used as the thermally expandable microspheres. Specific examples of thermally expandable microspheres of commercially available products include Matsumoto Microsphere (grade: F-30, F-30D, F-36D, F-36LV, F-50, F- F-180D, F-190D, F-190D, F-260D and F-2800D manufactured by Nippon Phillips Co., (Grade: H750, H850, H1100, S2320D, S2640D, M330, M430, M520) manufactured by Kureha Chemical Industries, Ltd., (Grades: EML101, EMH204, EHM301, EHM302, EHM303, EM304, EHM401, EM403 and EM501) manufactured by Igagaku Kogyo Co., Ltd., and the like.

The particle size of the heat-expandable microspheres prior to heating is preferably 0.5 to 80 탆, more preferably 5 to 45 탆, further preferably 10 to 20 탆, particularly preferably 10 to 20 탆, 15 mu m. Therefore, the particle size of the heat-expandable microspheres prior to heating is preferably from 6 탆 to 45 탆, and more preferably from 15 탆 to 35 탆, in terms of the average particle diameter. The particle diameter and the average particle diameter are values obtained by the particle size distribution measurement method in the laser scattering method.

The thermally expandable microspheres preferably have a suitable strength not ruptured until the volume expansion rate is preferably 5 times or more, more preferably 7 times or more, and even more preferably 10 times or more. When such thermally expandable microspheres are used, the adhesive force can be effectively lowered by the heat treatment.

B-3. Characteristics of the first pressure sensitive adhesive layer

The thickness of the first pressure-sensitive adhesive layer is preferably 1 탆 to 100 탆, more preferably 5 탆 to 80 탆, and particularly preferably 10 탆 to 50 탆. As described above, the first pressure sensitive adhesive layer is a layer containing thermally expandable microspheres. Therefore, the thickness of the first pressure-sensitive adhesive layer is preferably set such that the outer surface of the first pressure-sensitive adhesive layer (the surface opposite to the substrate) when the cross section in the thickness direction of the first pressure-sensitive adhesive layer is observed, The distance to the inner end.

The difference (thickness-average particle diameter) between the thickness of the first pressure-sensitive adhesive layer and the average particle diameter of the thermally expansible microspheres included in the first pressure-sensitive adhesive layer is preferably 8 占 퐉 or more, more preferably 10 占 퐉 or more More preferably 15 mu m or more, particularly preferably 20 mu m or more, and most preferably 25 mu m to 100 mu m. With such a range, the first pressure-sensitive adhesive layer has an appropriate surface roughness, and a heat-peelable pressure-sensitive adhesive sheet in which the chemical solution is less likely to enter the interface between the first pressure-sensitive adhesive layer and the adherend can be obtained.

The elastic modulus of the first pressure-sensitive adhesive layer in the nanoindentation method at 25 캜 is preferably 0.01 MPa to 50 MPa, more preferably 0.1 MPa to 10 MPa, and particularly preferably 0.5 MPa to 5 MPa. When the modulus of elasticity of the pressure-sensitive adhesive layer is in the above-mentioned range, a heat-peelable pressure-sensitive adhesive sheet having excellent tackiness, cuttability and step traceability can be obtained. The elastic modulus according to the nanoindentation method is a value obtained by continuously measuring the load applied to the indenter and the indentation depth when the indenter is press-fitted into the sample during the time of unloading and calculating the elastic modulus from the obtained load-indentation depth curve Refers to the elastic modulus. In the present specification, the elastic modulus according to the nanoindentation method refers to a modulus of elasticity measured under the conditions of a load of 1 mN, a load / unload rate of 0.1 mN / s, and a holding time of 1 s.

The elastic modulus of the first pressure-sensitive adhesive layer can be adjusted according to the composition of the base polymer constituting the pressure-sensitive adhesive in the pressure-sensitive adhesive layer. Further, the modulus of elasticity may be adjusted by adding an additive to the first pressure-sensitive adhesive layer. For example, when beads are contained in the first pressure-sensitive adhesive layer, the modulus of elasticity of the pressure-sensitive adhesive layer can be increased. Examples of the beads include glass beads and resin beads. The average particle diameter of the beads is, for example, 0.01 탆 to 50 탆. The amount of the beads to be added is, for example, 10 parts by weight to 200 parts by weight, preferably 20 parts by weight to 100 parts by weight, relative to 100 parts by weight of the whole pressure-sensitive adhesive layer.

The centerline average surface roughness (Ra) of the adhesive surface of the first pressure-sensitive adhesive layer is preferably 1 占 퐉 or less, more preferably 0.01 占 퐉 to 1 占 퐉, still more preferably 0.03 占 퐉 to 0.8 占 퐉, 0.06 占 퐉 to 0.6 占 퐉. With such a range, it is possible to obtain a heat-peelable pressure-sensitive adhesive sheet in which the chemical solution is less likely to enter the interface between the first pressure-sensitive adhesive layer and the adherend. The surface roughness (Ra) is measured in accordance with JIS B 0601.

The contact angle of water with respect to the first pressure-sensitive adhesive layer is preferably 85 ° to 115 °, more preferably 87 ° to 115 °, and particularly preferably 90 ° to 115 °. When the contact angle of water is larger than 115 DEG, that is, when the pressure-sensitive adhesive layer has high hydrophobicity, there is a fear that sufficient adhesive property can not be obtained. On the other hand, when the contact angle of water is smaller than 85 °, that is, when the hydrophobicity of the pressure-sensitive adhesive layer is too low, there is a possibility that the chemical liquid enters the interface between the pressure-sensitive adhesive layer and the adherend.

The gel fraction of the first pressure-sensitive adhesive layer is preferably 50% or more, more preferably 52% to 99%, and still more preferably 55% to 99%. In such a range, penetration of the chemical liquid into the pressure-sensitive adhesive layer can be prevented. The gel fraction of the pressure-sensitive adhesive layer can be adjusted by controlling the composition of the base polymer constituting the pressure-sensitive adhesive, the kind and content of the cross-linking agent, the kind and content of the tackifier, and the like. A method of measuring the gel fraction will be described later.

C. Second pressure-sensitive adhesive layer

C-1. adhesive

The second pressure sensitive adhesive layer includes any suitable pressure sensitive adhesive. As the pressure-sensitive adhesive contained in the second pressure-sensitive adhesive layer, from the viewpoint of adhesion, and in the case where the second pressure-sensitive adhesive layer contains the thermally-expanded microspheres, from the viewpoint of not constraining the expansion or foaming of the heat- Acrylic pressure sensitive adhesives, rubber pressure sensitive adhesives, vinyl alkyl ether pressure sensitive adhesives, silicone pressure sensitive adhesives, polyester pressure sensitive adhesives, polyamide pressure sensitive adhesives, urethane pressure sensitive adhesives, styrene - diene block copolymer pressure sensitive adhesives, and active energy ray curable pressure sensitive adhesives. Further, the pressure-sensitive adhesive may be a creep property improving type pressure-sensitive adhesive containing a heat-fusible resin having a melting point of about 200 ° C or less. Details of the creep property improving type pressure-sensitive adhesive are described in JP-B-56-61468 and JP-A-63-17981. Of the above pressure-sensitive adhesives, acrylic pressure-sensitive adhesives or rubber pressure-sensitive adhesives can be preferably used. The pressure-sensitive adhesives may be used alone or in combination of two or more.

As the acrylic pressure-sensitive adhesive contained in the second pressure-sensitive adhesive layer, any appropriate acrylic pressure-sensitive adhesive may be used. For example, an acrylic pressure sensitive adhesive using an acrylic polymer (homopolymer or copolymer) using one or two or more of (meth) acrylic acid alkyl esters as a monomer component as a base polymer. In one embodiment, the acrylic pressure-sensitive adhesive I described in the above section B is used.

Examples of the rubber-based pressure-sensitive adhesive include natural rubber; Butadiene rubber, styrene-butadiene rubber, styrene-isoprene rubber, styrene-isoprene-styrene block copolymer (SIS) rubber, styrene-butadiene styrene block copolymer (SBS) Butadiene rubber, styrene-butadiene-styrene block copolymer (SEBS) rubber, styrene-ethylene-propylene-styrene block copolymer (SEPS) rubber, styrene-ethylene-propylene block copolymer (SEP) , Synthetic rubber such as modified products thereof, and the like can be mentioned.

As the pressure-sensitive adhesive contained in the second pressure-sensitive adhesive layer, an active energy ray-curable pressure-sensitive adhesive which can be cured (high elastic modulus) by irradiation with active energy rays may be used. When the active energy ray-curable pressure-sensitive adhesive is used, the pressure-sensitive adhesive sheet which is low in elasticity at the time of attachment and excellent in handling properties because of its high flexibility, Can be obtained. Examples of the active energy ray include gamma ray, ultraviolet ray, visible ray, infrared ray (heat ray), radio wave, alpha ray, beta ray, electron ray, plasma ray, ion beam and particle ray.

As a resin material constituting the active energy ray-curable pressure-sensitive adhesive, there can be mentioned, for example, an ultraviolet curing system (published by Kato Kiyomi, Integrated Technology Center, (1989) Open Publication No. 2003-292916, and Japanese Patent No. 4151850, and the like. More specifically, there can be mentioned a resin material (R1) containing a polymer to be aggregated and an active energy ray-reactive compound (monomer or oligomer), and a resin material (R2) containing an active energy ray-reactive polymer.

Examples of the polymer that can be used as the polymer include natural rubber, polyisobutylene rubber, styrene / butadiene rubber, styrene / isoprene / styrene block copolymer rubber, regenerated rubber, butyl rubber, polyisobutylene rubber, nitrile rubber ); Silicone-based polymers; Acrylic polymers and the like. These polymers may be used singly or in combination of two or more kinds.

Examples of the active energy ray-reactive compound include photoreactive monomers or oligomers having a functional group having a carbon-carbon multiple bond such as an acryloyl group, a methacryloyl group, a vinyl group, an allyl group, and an acetylene group . Specific examples of the photoreactive monomer or oligomer include trimethylolpropane tri (meth) acrylate, tetramethylolmethane tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra Acrylate, dipentaerythritol hexa (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexane diol di (meth) acrylate, dipentaerythritol monohydroxypenta (Meth) acryloyl group-containing compounds such as polyethylene glycol di (meth) acrylate; And 2- to 5-mer of the (meth) acryloyl group-containing compound.

Examples of the active energy ray-reactive compound include monomers such as epoxidized butadiene, glycidyl methacrylate, acrylamide, and vinyl siloxane; Or an oligomer composed of the monomer may be used. The resin material (R1) containing these compounds can be cured by high energy rays such as ultraviolet rays and electron beams.

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 heterocyclic rings in a molecule may be used. The mixture of the organic salts is cleaved by irradiation of active energy rays (for example, ultraviolet rays, electron beams) to generate ions, which are initiated to cause a ring-opening reaction of the heterocyclic ring to form a three-dimensional mesh structure . Examples of the organic salts include iodonium salts, phosphonium salts, antimonium salts, sulfonium salts, borate salts and the like. Examples of the heterocycle in the compound having a plurality of heterocyclic rings in the molecule include oxirane, oxetane, oxolane, thiirane, and aziridine.

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 heterocyclic rings in a molecule may be used. The mixture of the organic salts is cleaved by irradiation of active energy rays (for example, ultraviolet rays, electron beams) to generate ions, which are initiated to cause a ring-opening reaction of the heterocyclic ring to form a three-dimensional mesh structure . Examples of the organic salts include iodonium salts, phosphonium salts, antimonium salts, sulfonium salts, borate salts and the like. Examples of the heterocycle in the compound having a plurality of heterocyclic rings in the molecule include oxirane, oxetane, oxolane, thiirane, and aziridine.

In the resin material (R1) comprising the polymer to be aggregated and the active energy ray-reactive compound, the content of the active energy ray-reactive compound is preferably from 0.1 to 500 parts by weight per 100 parts by weight of the polymer More preferably 1 part by weight to 300 parts by weight, and still more preferably 10 parts by weight to 200 parts by weight.

The resin material (R1) containing the above-mentioned polymer to be aggregated and the active energy ray-reactive compound may optionally contain any suitable additives. As the additive, for example, an active energy ray polymerization initiator, an active energy ray polymerization accelerator, a crosslinking agent, a plasticizer, a vulcanizing agent and the like can be given. As the active energy ray polymerization initiator, any suitable initiator may be used depending on the kind of active energy ray to be used. The active energy ray polymerization initiators may be used singly or in combination of two or more kinds. In the resin material (R1) containing the polymer to be aggregated and the active energy ray-reactive compound, the content of the active energy ray polymerization initiator is preferably 0.1 part by weight to 10 parts by weight More preferably 1 part by weight to 5 parts by weight.

Examples of the active energy ray-reactive polymer include a polymer having a functional group having a carbon-carbon multiple bond such as an acryloyl group, a methacryloyl group, a vinyl group, an allyl group, and an acetylene group. Specific examples of the polymer having an active energy ray-reactive functional group include a polymer composed of a polyfunctional (meth) acrylate; A photo cationic polymerizable polymer; A neomoyl group-containing polymer such as polyvinyl cinnamate; Diazotized aminovorak resins; Polyacrylamide, and the like. As the resin material (R2) containing the active energy ray-reactive polymer, a mixture of a compound having an active energy ray-reactive polymer having an allyl group and a compound having a thiol group may also be used. In addition, as long as a pressure-sensitive adhesive layer precursor having practically acceptable hardness (viscosity) can be formed before curing by irradiation with active energy rays (for example, when attaching a heat-peelable pressure-sensitive adhesive sheet) , An oligomer having an active energy ray-reactive functional group may be used.

The resin material (R2) comprising the active energy ray-reactive polymer may further contain the active energy ray-reactive compound (monomer or oligomer). Further, the resin material (R2) containing the active energy ray-reactive polymer may contain any suitable additives, if necessary. Specific examples of the additive are the same as the additive that can be contained in the resin material (R1) containing the polymer to be aggregated and the active energy ray-reactive compound. In the resin material (R2) containing the active energy ray-reactive polymer, the content of the active energy ray polymerization initiator is preferably 0.1 to 10 parts by weight based on 100 parts by weight of the active energy ray- Preferably 1 part by weight to 5 parts by weight.

The pressure-sensitive adhesive contained in the second pressure-sensitive adhesive layer may contain any suitable additives, if necessary. Examples of the additives to be used include the additives described in the above section B-1. The addition amount of the additive (tackifier, cross-linking agent, etc.) is preferably the addition amount described in the section B-1. Therefore, in one embodiment, the second pressure sensitive adhesive layer may contain a tackifier, and the content of the tackifier is preferably 40 parts by weight or less based on 100 parts by weight of the pressure sensitive adhesive layer, More preferably 30 parts by weight or less, still more preferably 25 parts by weight or less, and still more preferably 3 parts by weight to 25 parts by weight.

C-2. Thermally expandable microsphere

In one embodiment, the second pressure-sensitive adhesive layer further includes the thermally expandable microspheres described in the section B-2. The content of the thermally expandable microspheres in the second pressure-sensitive adhesive layer is, for example, 1 part by weight to 150 parts by weight, preferably 10 parts by weight To 130 parts by weight, more preferably 25 parts by weight to 100 parts by weight.

C-3. Properties of the second pressure sensitive adhesive layer

The thickness of the second pressure-sensitive adhesive layer is preferably 1 m to 100 m, more preferably 5 m to 80 m, and particularly preferably 10 m to 50 m. When the second pressure-sensitive adhesive layer contains thermally expandable microspheres, the thickness of the second pressure-sensitive adhesive layer is preferably such that the thickness of the second pressure-sensitive adhesive layer The distance from the outer surface (the surface opposite to the substrate) to the innermost end of the thermally expandable microspheres closest to the substrate.

When the second pressure-sensitive adhesive layer contains thermally expandable microspheres, the difference between the thickness of the second pressure-sensitive adhesive layer and the average particle diameter of the thermally expandable microspheres contained in the second pressure-sensitive adhesive layer (thickness-average particle diameter) Is preferably 8 占 퐉 or more, more preferably 10 占 퐉 or more, further preferably 15 占 퐉 or more, particularly preferably 25 占 퐉 or more, and most preferably 25 占 퐉 to 100 占 퐉.

The elastic modulus of the second pressure-sensitive adhesive layer in the nanoindentation method at 25 캜 is preferably 0.01 MPa to 50 MPa, more preferably 0.1 MPa to 10 MPa, and particularly preferably 0.5 MPa to 5 MPa.

The centerline average surface roughness (Ra) of the adhesive surface of the second pressure-sensitive adhesive layer is preferably 1 占 퐉 or less, more preferably 0.01 占 퐉 to 1 占 퐉, still more preferably 0.03 占 퐉 to 0.8 占 퐉, 0.06 占 퐉 to 0.6 占 퐉.

The contact angle of water with respect to the second pressure sensitive adhesive layer is preferably 85 to 115, more preferably 87 to 115, and particularly preferably 90 to 115.

The gel fraction of the second pressure sensitive adhesive layer is preferably 50% or more, more preferably 52% to 99%, still more preferably 55% to 99%. In such a range, penetration of the chemical liquid into the pressure-sensitive adhesive layer can be prevented.

D. Substrate

Examples of the base material include a resin sheet, a nonwoven fabric, a paper, a metal foil, a woven fabric, a rubber sheet, and a foamed sheet. Further, a substrate composed of the laminate (particularly, a laminate including a resin sheet), or a composite substrate made of the plurality of materials may be used. Examples of the resin constituting the resin sheet include a resin such as a polyethylene terephthalate (PET), a polyethylene naphthalate (PEN), a polybutylene terephthalate (PBT), a polyethylene (PE), a polypropylene (PP), an ethylene- (EVA), polyamide (nylon), wholly aromatic polyamide (aramid), polyimide (PI), polyvinyl chloride (PVC), polyphenylene sulfide (PPS) Ether ether ketone (PEEK), urethane acrylate, and acrylic resin (preferably UV-curable acrylic resin). Among them, PET, PEN, PE or PP may preferably be used in view of acid resistance. Examples of the nonwoven fabric include nonwoven fabrics made of natural fibers having heat resistance such as nonwoven fabric including manila marc; Nonwoven fabrics such as polypropylene resin nonwoven fabric, polyethylene resin nonwoven fabric, and ester based nonwoven fabric.

It is preferable that the above substrate has an elastic modulus by the nanoindentation method at 25 DEG C of 10 MPa to 10 GPa. The elastic modulus of the base material by the nanoindentation method at 25 캜 is more preferably from 100 MPa to 5 GPa, and particularly preferably from 500 MPa to 5 GPa. In such a range, a heat-peelable pressure-sensitive adhesive sheet excellent in cutting property and handling property at the time of bonding can be obtained.

The thickness of the base material is preferably from 1 탆 to 1000 탆, more preferably from 2 탆 to 250 탆, and particularly preferably from 10 탆 to 100 탆. In such a range, a heat-peelable pressure-sensitive adhesive sheet excellent in cutting property and handling property at the time of bonding can be obtained.

The substrate may be subjected to a surface treatment. Examples of the surface treatment include corona treatment, chromic acid treatment, ozone exposure, flame exposure, high voltage exposure, ionizing radiation treatment, coating treatment with an organic coating material, and the like. By performing such a surface treatment, the adhesion between the pressure-sensitive adhesive layer and the substrate can be enhanced, and the penetration of the chemical into the interface between the pressure-sensitive adhesive layer and the substrate can be suppressed. Particularly, the coating treatment with the organic coating material is preferable in that the graft destruction of the pressure-sensitive adhesive layer can be suppressed at the time of heat peeling.

Examples of the organic coating material include materials described in, for example, Plastic Hard Coating Material II (CMC Publishing, (2004)). Preferably, a urethane-based polymer, more preferably a polyacryl urethane, a polyester urethane or a precursor thereof is used. This is because the application to the base material is simple, and a large variety of materials can be industrially selected and can be obtained at low cost. The urethane-based polymer is a polymer containing a reaction mixture of, for example, an isocyanato 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, as an optional additive, a chain extender such as polyamine, an antioxidant, an oxidation stabilizer and the like. The thickness of the organic coating layer is not particularly limited. For example, the thickness of the organic coating layer is suitably about 0.1 탆 to 10 탆, preferably about 0.1 탆 to 5 탆, and more preferably about 0.5 탆 to 5 탆. (Trade name: AP2500E) and trade name &quot; CL2500 &quot; as a curing agent) manufactured by Arakawa Chemical Industries, Ltd., trade name &quot; NB300 &quot; Commercially available products may be used.

E. Elastic layer

As described above, the heat-peelable pressure-sensitive adhesive sheet of the present invention may further comprise an elastic layer.

The elastic layer includes a base polymer, and as the base polymer, a sticky polymer may be used. Examples of the base polymer constituting the elastic layer include rubber polymers such as (meth) acrylic polymers such as natural rubber and synthetic rubber (for example, nitrile, diene and acrylic); Thermoplastic elastomers such as polyolefin type and polyester type; Vinyl alkyl ether polymers; Silicone-based polymers; Polyester-based polymers; Polyamide-based polymers; Urethane polymer; Styrene-diene block copolymer; Ethylene-vinyl acetate copolymer; Polyurethane polymers; Polybutadiene; Flexible polyvinyl chloride; Radiation curable polymers, and the like. The base polymer constituting the elastic layer may be the same as or different from the base polymer forming the pressure-sensitive adhesive layer (the first pressure-sensitive adhesive layer and / or the second pressure-sensitive adhesive layer). The elastic layer may be a foamed film formed of the base polymer. The foamed film can be obtained by any suitable method. Further, the elastic layer and the first pressure-sensitive adhesive layer (and the second pressure-sensitive adhesive layer including the thermally expandable microspheres) can be distinguished by the presence or absence of the thermally expandable microspheres (the elastic layer does not include the thermally expandable microspheres).

The (meth) acrylic polymer as the base polymer constituting the elastic layer is, for example, an acrylic polymer (a homopolymer or a copolymer) using one or two or more kinds of (meth) acrylic acid alkyl esters as a monomer component. Examples of the (meth) acrylic acid alkyl ester include (meth) acrylic acid alkyl esters having a straight chain or branched alkyl group having not more than 20 carbon atoms. In addition, the acrylic polymer may contain units corresponding to other monomer components copolymerizable with the (meth) acrylic acid alkyl ester. Examples of such monomer components include acrylic acid, methacrylic acid, itaconic acid, hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, N-methylol acrylamide, Nitrile, methacrylonitrile, glycidyl acrylate, glycidyl methacrylate, vinyl acetate, styrene, isoprene, butadiene, isobutylene, vinyl ether and the like.

The elastic layer may contain any suitable additives, if necessary. Examples of the additive include a cross-linking agent, a vulcanizing agent, a tackifier, a plasticizer, a softener, a filler, and an antioxidant. When a hard resin such as polyvinyl chloride is used as the base polymer, it is preferable to use a plasticizer and / or a softener in combination to form an elastic layer having desired elasticity.

The thickness of the elastic layer is preferably 3 탆 to 200 탆, and more preferably 5 탆 to 100 탆. If it is in this range, the above function of the elastic layer can be sufficiently exhibited.

The elastic modulus of the elastic layer at 25 캜 is preferably less than 100 MPa, more preferably 0.1 MPa to 50 MPa, and still more preferably 0.1 MPa to 10 MPa. If it is in this range, the above function of the elastic layer can be sufficiently exhibited.

F. Method for producing heat-peelable pressure-sensitive adhesive sheet

The heat-peelable pressure-sensitive adhesive sheet of the present invention can be produced by any suitable method. The heat-peelable pressure-sensitive adhesive sheet of the present invention can be obtained, for example, by applying a composition for forming a first pressure-sensitive adhesive layer directly on one side of a base material and directly applying a composition for forming a second pressure- , A method of transferring a coating applied layer formed by applying and coating on any appropriate gas to a substrate to form a first pressure-sensitive adhesive layer and a second pressure-sensitive adhesive layer, and the like. The pressure-sensitive adhesive layer containing thermally expandable microspheres can be obtained by forming a pressure-sensitive adhesive application layer with a composition containing a pressure-sensitive adhesive, spraying thermally expandable microspheres to the pressure-sensitive adhesive application layer, Thermally expandable microspheres may be embedded in the applied coating layer.

The composition for forming a first pressure-sensitive adhesive layer includes the acrylic pressure-sensitive adhesive I and the heat-expandable microspheres, and optionally includes any suitable solvent. The composition for forming the second pressure-sensitive adhesive layer includes any suitable pressure-sensitive adhesive, and optionally includes the thermally expandable microspheres and / or any suitable solvent.

When the heat-peelable pressure-sensitive adhesive sheet has the elastic layer, the pressure-sensitive adhesive layer adjacent to the elastic layer and the elastic layer may be formed by applying a composition for forming an elastic layer, for example, A composition for forming a layer can be formed by applying and coating. For example, a composition for forming an elastic layer containing a material for forming an elastic layer (a base polymer, an additive and the like) is applied on a substrate, and then a first layer The elastic layer and the first pressure-sensitive adhesive layer can be formed in this order from the substrate side by applying the pressure-sensitive adhesive composition.

As a method of applying each of the above compositions, any suitable application method can be employed. For example, each layer can be formed by drying after application. Examples of the application method include a coating method using a multi-coater, a die coater, a gravure coater, an applicator, or the like. Examples of the drying method include natural drying, heat drying and the like. The heating temperature in the case of heating and drying can be set to any appropriate temperature depending on the characteristics of the material to be dried.

G. Uses

The heat-peelable pressure-sensitive adhesive sheet of the present invention can be suitably used as a protective sheet for producing electronic parts. Particularly, when the electronic component is treated (for example, etching treatment) by using an acidic or alkaline chemical solution, it can be suitably used as a protective sheet for protecting the electronic component.

The heat-peelable pressure-sensitive adhesive sheet of the present invention is a double-faced pressure-sensitive adhesive sheet, and the electronic parts are adhered to both surfaces of the pressure-sensitive adhesive sheet to provide the electronic parts to the processing step, . In addition, by performing the treatment process in this way, the production efficiency can be improved.

[Example]

Hereinafter, the present invention will be described concretely with reference to examples, but the present invention is not limited to these examples. In the examples, &quot; part &quot; and &quot;% &quot; are by weight unless otherwise specified.

[Preparation Example 1] Preparation of acrylic pressure-sensitive adhesive I (i)

, 100 parts by weight of a (meth) acrylic polymer (copolymer of butyl acrylate (BA) and acrylic acid (AA), constituent unit derived from BA: constituent unit derived from AA (weight ratio) = 95: 5) , 0.6 part by weight of a trade name &quot; TETRAD C &quot;, manufactured by Kagaku Co., Ltd.) and 30 parts by weight of a terpene phenol tackifier resin (trade name: YS POLYSTAR T130 available from Yasuhara Chemical Co., Respectively.

[Production Examples 2 to 9] Preparation examples of acrylic pressure-sensitive adhesives I (ii) to (ix)

Acrylic pressure-sensitive adhesives I (ii) to (ix) were prepared by mixing the (meth) acrylic polymer, the crosslinking agent and the tackifier resin shown in Table 1 in the amounts shown in Table 1.

Tertrad X: Epoxy crosslinking agent; Manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name &quot; Tertrad X &quot;

Coronate L: isocyanate-based crosslinking agent; Manufactured by Nippon Polyurethane Industry Co., Ltd., trade name &quot; Coronate L &quot;

Superester A-75: rosin-based tackifier resin; Arakawa Kagaku Kogyo Co., Ltd., trade name "SUPERESTER A-75"

Tamanol 200: alkylphenol-based tackifying resin; Arakawa Kagaku Kogyo Co., Ltd., trade name &quot; Tamanol 200 &quot;

[Table 1]

[Example 1]

130.6 parts by weight of the acrylic pressure-sensitive adhesive I (i) obtained in Preparation Example 1, 25 parts by weight of a thermally expandable microspheres (trade name: Matsumoto Microsphere F-50D, manufactured by Matsumoto Yushi Seiyaku Co., Ltd.) and 210 parts by weight of toluene were mixed , A composition (i) for forming a pressure-sensitive adhesive layer was prepared.

The composition (i) for forming a pressure-sensitive adhesive layer was coated on both sides of a PET film (trade name: "Lumirror S10", trade name, manufactured by Toray Co., Ltd., thickness: 100 μm) as a substrate to form a first pressure- Layer.

By this operation, a heat-peelable pressure-sensitive adhesive sheet comprising a first pressure-sensitive adhesive layer (40 占 퐉), a substrate (100 占 퐉) and a second pressure-sensitive adhesive layer (40 占 퐉) in this order was obtained.

[Example 2]

130.6 parts by weight of the acrylic pressure-sensitive adhesive I (i) obtained in Preparation Example 1, 30 parts by weight of thermally expandable microspheres (trade name: Matsumoto Microsphere F-48D, manufactured by Matsumoto Yushi Seiyaku Co., Ltd.) and 210 parts by weight of toluene were mixed, (Ii) for forming a layer was prepared.

As a composition (i) for forming an elastic layer, a mixture of 130.6 parts by weight of the acrylic pressure-sensitive adhesive I (i) and 210 parts by weight of toluene was prepared. As a composition (ii) for forming the elastic layer, a mixture of 130.1 parts by weight of the acrylic pressure-sensitive adhesive I (ii) obtained in Production Example 2 and 210 parts by weight of toluene was prepared.

A composition for forming an elastic layer (i) and a composition for forming an adhesive layer (ii) were applied in this order on one side of a polyester film as a substrate (product of Mitsubishi Rayon Co., Ltd., Layer (thickness: 20 mu m) and a first pressure-sensitive adhesive layer (thickness: 40 mu m) were formed. The composition for forming an elastic layer (ii) and the composition for forming a pressure-sensitive adhesive layer (ii) were applied in this order on the other side of the substrate to form an elastic layer having a thickness of 20 m and a second pressure- ).

By this operation, the first pressure sensitive adhesive layer (40 占 퐉), the elastic layer (20 占 퐉), the substrate (50 占 퐉), the elastic layer (20 占 퐉) and the second pressure sensitive adhesive layer Thereby obtaining a heat-peelable pressure-sensitive adhesive sheet.

[Example 3]

, 151 parts by weight of the acrylic pressure-sensitive adhesive (iii) obtained in Production Example 3, 40 parts by weight of thermally expandable microspheres (trade name: Matsumoto Microsphere FN-100SD, manufactured by Matsumoto Yushi Seiyaku Co., Ltd.) and 210 parts by weight of toluene, (Iii) was prepared.

As a composition (iii) for forming an elastic layer, a mixture of 101 parts by weight of the acrylic pressure-sensitive adhesive I (iv) obtained in Production Example 4 and 210 parts by weight of toluene was prepared.

A composition for forming an elastic layer (iii) and a composition for forming a pressure-sensitive adhesive layer (iii) were applied and applied in this order on one side of a PET film (Lamierer S10, (Thickness: 30 mu m) and a first pressure-sensitive adhesive layer (thickness: 30 mu m) were formed. The elastic layer (thickness: 15 占 퐉) and the second pressure-sensitive adhesive layer (thickness: 15 占 퐉) were applied on the other side of the base material in this order by applying the composition for forming an elastic layer (iii) 20 mu m).

(30 占 퐉), an elastic layer (30 占 퐉), a base material (100 占 퐉), an elastic layer (15 占 퐉) and a second pressure-sensitive adhesive layer Thereby obtaining a heat-peelable pressure-sensitive adhesive sheet.

[Example 4]

122 parts by weight of the acrylic pressure-sensitive adhesive (v) obtained in Preparation Example 5, 30 parts by weight of thermally expandable microspheres (trade name "X-Panle 909-DU80" manufactured by Nippon Pylil Co., Ltd.) and 210 parts by weight of toluene were mixed to form a pressure- Composition (iv) was prepared.

A mixture of 112 parts by weight of the acrylic pressure-sensitive adhesive I (vi) obtained in Production Example 6 and 210 parts by weight of toluene was prepared as the composition (iv) for forming the elastic layer.

A composition for forming an elastic layer (iv) and a composition for forming an adhesive layer (iv) were applied and formed in this order on one side of a PET film as a base material (trade name: Lamierer S10, (Thickness: 25 mu m) and a first pressure-sensitive adhesive layer (thickness: 50 mu m) were formed. The elastic layer (thickness: 20 占 퐉) and the second pressure-sensitive adhesive layer (thickness: 20 占 퐉) were applied on the other surface of the substrate in the order of the composition (iv) 30 mu m) was formed.

(50 占 퐉), an elastic layer (25 占 퐉), a base material (50 占 퐉), an elastic layer (20 占 퐉) and a second pressure-sensitive adhesive layer Thereby obtaining a heat-peelable pressure-sensitive adhesive sheet.

[Comparative Example 1]

140.7 parts by weight of the acrylic pressure-sensitive adhesive I (vii) obtained in Preparation Example 7, 25 parts by weight of thermally expandable microspheres (trade name: Matsumoto Microsphere F-50D, manufactured by Matsumoto Yushi Seiyaku Co., Ltd.) and 210 parts by weight of toluene were mixed , And a composition (v) for forming a pressure-sensitive adhesive layer were prepared.

The composition (v) for forming a pressure-sensitive adhesive layer was coated on both sides of a PET film (trade name: "Lumirror S10", trade name, manufactured by Toray Co., Ltd., thickness: 100 μm) as a substrate to form a first pressure- Layer.

By the above operation, a heat-peelable pressure-sensitive adhesive sheet comprising a first pressure-sensitive adhesive layer (45 μm), a substrate (100 μm) and a second pressure-sensitive adhesive layer (45 μm) in this order was obtained.

[Comparative Example 2]

127 parts by weight of the acrylic pressure-sensitive adhesive I (viii) obtained in Production Example 8, 30 parts by weight of thermally expandable microspheres (trade name "X-Panle 909-DU80", manufactured by Nippon Phillle Co., Ltd.) and 210 parts by weight of toluene were mixed to form a pressure- (Vi) was prepared.

As a composition (vi) for forming the elastic layer, a mixture of 117 parts by weight of the acrylic pressure-sensitive adhesive I (ix) obtained in Production Example 9 and 210 parts by weight of toluene was prepared.

A composition for forming an elastic layer (vi) and a composition for forming a pressure-sensitive adhesive layer (vi) were applied and applied in this order on one side of a PET film as a base material (trade name: "Lamiron S10" (Thickness: 20 占 퐉) and a first pressure-sensitive adhesive layer (thickness: 40 占 퐉) were formed. Further, a pressure-sensitive adhesive layer-forming composition (vi) was coated on the other side of the substrate to form a second pressure-sensitive adhesive layer (40 m).

By this operation, a heat-peelable pressure-sensitive adhesive sheet comprising a first pressure-sensitive adhesive layer (40 占 퐉), an elastic layer (20 占 퐉), a substrate (100 占 퐉) and a second pressure- .

[evaluation]

The heat peelable pressure-sensitive adhesive sheets obtained in Examples and Comparative Examples were provided for the following evaluation. The results are shown in Table 2.

(1) Centerline average surface roughness (Ra)

The center line average surface roughness (Ra) on the side of the first pressure sensitive adhesive layer was measured according to JIS B 0601. Specifically, measurement conditions were measured as follows using an optical surface roughness meter (trade name: Wyko NT9100, manufactured by Veeco Metrogy Group). Table 2 shows the average of measured values obtained by measuring five times in the vertical and horizontal directions.

(Evaluation condition)

Sample dimensions: 50mm × 50mm

Measuring range: 2.534mm × 1.901mm

Measurement mode: VSL

Objective lens: 2.5 times

Inner lens: 1.0 times

(2) Contact angle

2 μl of pure water was dropped onto the surface of the first pressure-sensitive adhesive layer under the environment of 23 ° C./50% RH using a contact angle meter (trade name "CX-A type" manufactured by Kyowa Chemical Industry Co., Ltd.) The contact angle of the enemy was measured. Table 2 shows the average of the measured values obtained by five measurements.

(3) Gel fraction

0.1 g of the evaluation sample sampled from the first resin layer was surrounded by a mesh sheet and allowed to stand at room temperature for one week in 50 ml of toluene to immerse the sample in toluene. Thereafter, the toluene insoluble matter was taken out, dried at 70 ° C for 2 hours, and then the toluene insoluble matter after drying was weighed.

From the weight of the sample before immersion in toluene and the weight of the toluene insoluble matter, the gel fraction of the resin layer was calculated by the following formula.

Gel fraction (%) = [(weight of toluene insoluble matter) / (sample weight before toluene immersion)] × 100

(4) Adhesive force measurement method

A thermally peelable pressure-sensitive adhesive sheet was cut into a size of 20 mm in width and 140 mm in length and a polyethylene terephthalate film (trade name: "Lumirror S-10" manufactured by Toray Co., Ltd., thickness: Width: 20 mm) was pressed and bonded by a roll of 2 kg in one atmosphere under an atmosphere of temperature: 23 ± 2 ° C. and humidity: 65 ± 5% RH according to JIS Z 0237 (2000). Subsequently, the heat-peelable pressure-sensitive adhesive sheet having the adherend attached thereto was set in a tensile tester (manufactured by Shimadzu Seisakusho Co., Ltd., trade name "Shimazu Otograph AG-120kN") equipped with a thermostatic chamber set at 23 ° C and left for 30 minutes. After standing, the load was measured when the adherend was peeled from the heat-peelable pressure-sensitive adhesive sheet under the conditions of a temperature of 23 ° C and a peel angle of 180 ° and a peel rate (tensile rate) of 300 mm / min. (The maximum value of the load excluding the peak top at the initial stage of measurement) was determined, and this maximum load was determined as the adhesive force (N / 20 mm) of the first pressure-sensitive adhesive layer.

(5) Evaluation of chemical solution penetration

A heat-peelable pressure-sensitive adhesive sheet was cut into a size of 50 mm x 50 mm, a silicon wafer was placed on the first pressure-sensitive adhesive layer side, a glass plate (thickness: 1 mm) Under the conditions of 3 minutes, they were pressed to prepare samples for evaluation. Thereafter, the evaluation sample was immersed in a nitric acid solution having a concentration of 60% by weight at a temperature of 40 占 폚 for 10 minutes. After immersion, the amount of chemical solution penetration on the side of the first pressure sensitive adhesive layer was evaluated according to the liquid penetration distance from the end of the pressure sensitive adhesive sheet.

(6) Heat peelability

A sample for evaluation was prepared in the same manner as in the above (5) chemical-solution penetration evaluation. The sample for evaluation was heated at 130 占 폚 for 1 minute. The state of peeling of the silicon wafer after heating was visually confirmed. In Table 2, the case where the adhesive force of the pressure-sensitive adhesive layer is lost and the silicon wafer is peeled off is indicated by o, and the case where the pressure-sensitive adhesive layer has adhesive force and the silicon wafer is not peeled is evaluated as x.

[Table 2]

The heat-peelable pressure-sensitive adhesive sheet of the present invention can be suitably used as a protective tape of an electronic component provided in a treatment liquid such as an etching solution.

10: first pressure-sensitive adhesive layer
20: substrate
30: second pressure-sensitive adhesive layer
40: elastic layer
100, 200: heat-peelable pressure-sensitive adhesive sheet

Claims (9)

A first pressure sensitive adhesive layer, a base material, and a second pressure sensitive adhesive layer in this order,
Wherein the first pressure-sensitive adhesive layer comprises an acrylic pressure-sensitive adhesive comprising a (meth) acrylic polymer and a thermally expandable microsphere,
Wherein the (meth) acrylic polymer comprises a structural unit derived from a (meth) acrylic acid alkyl ester having an alkyl group having 2 or more carbon atoms and a structural unit derived from a (meth) acrylic monomer having an OH group,
Wherein the molar ratio (C / OH) of the carbon (C) to the OH group (C / OH) of the side chain alkyl group in the (meth) acrylic polymer is 40 to 150. The method according to claim 1,
Wherein the second pressure-sensitive adhesive layer comprises the thermally expandable microspheres. The method according to claim 1,
Wherein the center line average surface roughness (Ra) of the first pressure-sensitive adhesive layer and / or the second pressure-sensitive adhesive layer is 1 占 퐉 or less. The method according to claim 1,
Wherein the contact angle of water with respect to the first pressure-sensitive adhesive layer and / or the second pressure-sensitive adhesive layer is 85 ° to 115 °. The method according to claim 1,
Wherein the first pressure sensitive adhesive layer comprises a tackifier and the content of the tackifier is 40 parts by weight or less based on 100 parts by weight of the first pressure sensitive adhesive layer. The method according to claim 1,
Wherein the second pressure sensitive adhesive layer comprises a tackifier and the content of the tackifier is 40 parts by weight or less based on 100 parts by weight of the second pressure sensitive adhesive layer. The method according to claim 1,
Wherein the gel fraction of the first pressure-sensitive adhesive layer and / or the second pressure-sensitive adhesive layer is 50% or more. The method according to claim 1,
Wherein the adhesive force at 23 캜 when the first pressure sensitive adhesive layer side is bonded to the polyethylene terephthalate film is 1 N / 20 mm or more. An electronic part manufactured using the heat-peelable pressure-sensitive adhesive sheet according to claim 1.

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