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WO2025205624A1 - Feuille adhésive, structure, procédé de production de structure et procédé - Google Patents

Feuille adhésive, structure, procédé de production de structure et procédé

Info

Publication number
WO2025205624A1
WO2025205624A1 PCT/JP2025/011484 JP2025011484W WO2025205624A1 WO 2025205624 A1 WO2025205624 A1 WO 2025205624A1 JP 2025011484 W JP2025011484 W JP 2025011484W WO 2025205624 A1 WO2025205624 A1 WO 2025205624A1
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WO
WIPO (PCT)
Prior art keywords
weight
less
parts
polymer
meth
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
PCT/JP2025/011484
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English (en)
Japanese (ja)
Inventor
有義 金田
健太 熊倉
哲士 本田
優樹 東別府
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nitto Denko Corp
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Nitto Denko Corp
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Application filed by Nitto Denko Corp filed Critical Nitto Denko Corp
Publication of WO2025205624A1 publication Critical patent/WO2025205624A1/fr
Pending legal-status Critical Current
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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J133/00—Adhesives based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Adhesives based on derivatives of such polymers
    • C09J133/04—Homopolymers or copolymers of esters
    • C09J133/14—Homopolymers or copolymers of esters of esters containing halogen, nitrogen, sulfur or oxygen atoms in addition to the carboxy oxygen
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/20—Adhesives in the form of films or foils characterised by their carriers
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/30—Adhesives in the form of films or foils characterised by the adhesive composition
    • C09J7/38—Pressure-sensitive adhesives [PSA]
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
    • H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
    • H01L21/304—Mechanical treatment, e.g. grinding, polishing, cutting
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
    • H01L21/683—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping

Definitions

  • Adhesives used in applications where the adhesive is peeled off from an adherend are required to exhibit good adhesion while attached to the adherend, and to have the ability to be easily removed from the adherend once its adhesive purpose has been fulfilled.
  • adhesives used on adherends that undergo heat treatment desirably have easy releasability, allowing them to be easily removed from the adherend after being heated while attached to the adherend.
  • an adhesive is heated at high temperatures to an adherend such as glass, metal, or resin
  • the adhesive adheres to the adherend surface, increasing the peel strength (heavy peeling), which can lead to problems such as reduced releasability and the generation of adhesive residue.
  • Non-Patent Documents 1 and 2 describe how various polymers acquire adhesive properties upon heating.
  • the thickness of the resin layer is 0.01 ⁇ m or more and less than 20 ⁇ m. A resin layer having a thickness within this range is likely to provide good anchoring properties.
  • acrylic monomer refers to a monomer having at least one (meth)acryloyl group in one molecule.
  • (meth)acryloyl group refers collectively to acryloyl groups and methacryloyl groups. Therefore, the concept of acrylic monomer here can encompass both monomers having an acryloyl group (acrylic monomers) and monomers having a methacryloyl group (methacrylic monomers).
  • (meth)acrylic acid refers collectively to acrylic acid and methacrylic acid
  • (meth)acrylate refers collectively to acrylate and methacrylate. The same applies to other similar terms.
  • the pressure-sensitive adhesive sheet disclosed herein is configured to include a pressure-sensitive adhesive layer.
  • the pressure-sensitive adhesive sheet is a substrate-attached pressure-sensitive adhesive sheet having the pressure-sensitive adhesive layer on one or both sides of a substrate (supporting substrate), and has a configuration in which the substrate layer (supporting substrate), a resin layer, and a pressure-sensitive adhesive layer are arranged in this order.
  • the concept of pressure-sensitive adhesive sheet here may include what are called pressure-sensitive adhesive tapes, pressure-sensitive adhesive labels, pressure-sensitive adhesive films, etc.
  • the pressure-sensitive adhesive sheet disclosed herein may be in the form of a roll or sheets. Alternatively, it may be a pressure-sensitive adhesive sheet in the form of a sheet that has been further processed into various shapes.
  • the adhesive sheet 1 is in the form of a single-sided adhesive sheet comprising a sheet-like substrate layer (support substrate) 10, a resin layer 15 provided on the first surface 10A of the substrate layer 10, and an adhesive layer 20 provided on the first surface 15A of the resin layer 15.
  • the adhesive sheet 1 is used by attaching the surface 20A of the adhesive layer 20, which is its adhesive surface 1A, to an adherend. More specifically, the second surface 15B of the resin layer 15 is in contact with the first surface 10A of the substrate layer 10, and the first surface 15A is in contact with the adhesive layer 20.
  • the adhesive layer may contain one or more polymers selected from various rubber-like polymers that can be used in the field of adhesives, such as acrylic polymers, rubber polymers (e.g., natural rubber, synthetic rubber, and mixtures thereof), polyester polymers, urethane polymers, polyether polymers, silicone polymers, polyamide polymers, and fluorine-based polymers.
  • the above polymers may be used as base polymers in adhesives and function as structural polymers that shape the adhesive. From the viewpoints of adhesive performance, cost, and the like, adhesives containing acrylic polymers or rubber polymers as base polymers are preferably used. Among these, adhesives (acrylic adhesives) that use acrylic polymers with excellent heat resistance as the base polymer are preferred.
  • the polymer contained in the adhesive layer is also referred to as polymer A.
  • the monomer component includes an alkoxy group-containing (meth)acrylate.
  • Acrylic polymers containing an alkoxy group-containing (meth)acrylate as a monomer component tend to provide good adhesion and also tend to be compatible with, for example, the monomers that may be included in the pressure-sensitive adhesive layer described below (hereinafter, sometimes referred to as "compound monomers" to distinguish them from the monomer components used in the synthesis of the polymer).
  • the alkoxy group-containing (meth)acrylates can be used alone or in combination of two or more.
  • alkoxy group-containing (meth)acrylates include alkoxyalkyl (meth)acrylates such as methoxyethyl (meth)acrylate, 3-methoxypropyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, propoxyethyl (meth)acrylate, butoxyethyl (meth)acrylate, and ethoxypropyl (meth)acrylate; alkoxy(poly)alkylene glycol (meth)acrylates such as methoxydiethylene glycol (meth)acrylate, methoxydipropylene glycol (meth)acrylate, ethoxydiethylene glycol (meth)acrylate, ethoxydipropylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, methoxypolypropylene glycol (meth)acrylate, ethoxypolyethylene glycol (meth)acrylate, and ethoxypolyprop
  • the upper limit of the content of the alkoxy group-containing (meth)acrylate in the above monomer components is approximately 99% by weight or less, may be 90% by weight or less, preferably 80% by weight or less, more preferably 70% by weight or less, even more preferably 65% by weight or less, and may be 60% by weight or less, from the viewpoint of introducing an ethylenically unsaturated group into the polymer and obtaining the effects of other copolymerizable monomers such as functional group-containing monomers.
  • the monomer component constituting the acrylic polymer may include a chain alkyl (meth)acrylate having a linear or branched alkyl group having from 1 to 20 carbon atoms at the ester terminal.
  • a chain alkyl (meth)acrylate having an alkyl group having from X to Y carbon atoms at the ester terminal may be referred to as a "C X-Y alkyl (meth)acrylate.”
  • chain is used to encompass both linear and branched chains.
  • the chain alkyl (meth)acrylates may be used alone or in combination of two or more.
  • C 1-20 alkyl (meth)acrylate examples include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, isopentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (
  • One C4-8 alkyl (meth)acrylate can be used alone, or two or more C4-8 alkyl (meth)acrylates can be used in combination.
  • the use of a C4-8 alkyl (meth)acrylate tends to make it easier to obtain good adhesive properties (such as adhesive strength).
  • an acrylic polymer containing one or both of n-butyl acrylate (BA) and 2-ethylhexyl acrylate (2EHA) as the monomer component is preferred, and an acrylic polymer containing at least 2EHA is particularly preferred.
  • a C 7-12 alkyl (meth)acrylate may be preferably used.
  • the C 7-12 alkyl (meth)acrylate may be used alone or in combination of two or more.
  • a C 7-10 alkyl acrylate is preferred, a C 7-9 alkyl acrylate is more preferred, and a C 8 alkyl acrylate is even more preferred.
  • the content of the C 1-20 alkyl (meth)acrylate in the monomer component is not particularly limited. From the viewpoint of effectively obtaining the effects of using the C 1-20 alkyl (meth)acrylate, in some embodiments, the content of the C 1-20 alkyl (meth)acrylate in the monomer component is typically about 1% by weight or more, for example, 10% by weight or more, 30% by weight or more, or 50% by weight or more (e.g., more than 50% by weight).
  • the monomer components constituting the acrylic polymer preferably include other monomers in addition to the above-mentioned alkoxyalkyl (meth)acrylates and linear alkyl (meth)acrylates.
  • Such other monomers may be monomers (copolymerizable monomers) copolymerizable with the alkoxyalkyl (meth)acrylates and linear alkyl (meth)acrylates.
  • the above-mentioned other monomers may be used, for example, to introduce ethylenically unsaturated groups into the polymer.
  • monomers having polar groups e.g., carboxy groups, hydroxyl groups, nitrogen atom-containing rings, etc.
  • Monomers having polar groups can be useful for introducing crosslinking points into the acrylic polymer or for increasing the cohesive strength of the adhesive.
  • the other monomers can be used alone or in combination of two or more.
  • the monomer component constituting the acrylic polymer includes a monomer having a nitrogen atom.
  • the use of a monomer having a nitrogen atom can increase the cohesive strength of the PSA and favorably improve the adhesive strength.
  • Examples of the monomer having a nitrogen atom that can be used include amide group-containing monomers, amino group-containing monomers, and monomers having a nitrogen atom-containing ring.
  • the monomer having a nitrogen atom can be used alone or in combination of two or more types.
  • Amino group-containing monomers for example, aminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, t-butylaminoethyl (meth)acrylate.
  • N-vinyl-2-pyrrolidone N-methylvinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, N-vinylpiperazine, N-vinylpyrazine, N-vinylpyrrole, N-vinylimidazole, N-vinyloxazole, N-(meth)acryloyl-2-pyrrolidone, N-(meth)acryloylpiperidine, N-(meth)acryloylpyrrolidine N-vinyl-2-caprolactam, N-vinyl-1,3-oxazin-2-one, N-vinyl-3,5-morpholinedione, N-vinylpyrazole, N-vinylisoxazole, N-vinylthiazole, N-vinylisothiazole, N-vinylpyridazine,
  • the amount of the nitrogen-containing monomer (preferably the nitrogen-containing ring monomer) used is not particularly limited. In some embodiments, the amount of the nitrogen-containing monomer used in the monomer component may be 1% by weight or more, or may be 3% by weight or more. In some preferred embodiments, the amount of the nitrogen-containing monomer used in the monomer component is 5% by weight or more, more preferably 7% by weight or more, even more preferably 9% by weight or more, or may be 10% by weight or more, 12% by weight or more, or may be 14% by weight or more. The greater the amount of the nitrogen-containing monomer used, the more the cohesive strength of the PSA tends to improve.
  • the monomer component includes a hydroxyl group-containing monomer.
  • a hydroxyl group-containing monomer can adjust the cohesive strength and crosslink density of the PSA, improving adhesive strength.
  • Hydroxyl group-containing monomers are also preferably used as a means of introducing ethylenically unsaturated groups into the polymer.
  • hydroxyl group-containing monomers examples include hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, and (4-hydroxymethylcyclohexyl)methyl (meth)acrylate.
  • 2-hydroxyethyl acrylate (HEA) and 4-hydroxybutyl acrylate (4HBA) are preferably used.
  • the hydroxyl group-containing monomers can be used alone or in combination of two or more.
  • the weight ratio (A N /A OH ) of the amount of nitrogen atom-containing monomer A N to the amount of hydroxyl group-containing monomer A OH is not particularly limited, and may be, for example, 0.1 or more, 0.5 or more, 1.0 or more, 1.2 or more, 1.5 or more, or 1.8 or more. Furthermore, the weight ratio (A N /A OH ) may be, for example, 10 or less, 5 or less, 3 or less, or 2.5 or less.
  • the monomer component may include a carboxy group-containing monomer.
  • carboxy group-containing monomers include acrylic acid (AA), methacrylic acid (MAA), carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid, etc.
  • Preferred examples include AA and MAA.
  • the carboxy group-containing monomers can be used alone or in combination of two or more. For example, AA and MAA can be used in combination.
  • the amount of carboxy group-containing monomer used may be, for example, 0.01% by weight or more, 0.1% by weight or more, 1% by weight or more, 3% by weight or more, 6% by weight or more, or 8% by weight or more of the total monomer components.
  • the proportion of the carboxy group-containing monomer may be, for example, 20% by weight or less, 10% by weight or less, 3% by weight or less, 1% by weight or less (e.g., less than 1% by weight), or 0.1% by weight or less.
  • the monomer components may be substantially free of carboxy group-containing monomer.
  • the other monomer a monomer having a functional group (functional group A) that can react with a functional group (functional group B) of a compound having an ethylenically unsaturated group, which will be described later.
  • the type of other monomer is determined by the type of compound.
  • examples of other monomers having functional group A include carboxy group-containing monomers, epoxy group-containing monomers, hydroxyl group-containing monomers, and isocyanate group-containing monomers, with hydroxyl group-containing monomers being particularly preferable.
  • the acrylic polymer will have a hydroxyl group.
  • the hydroxyl group of the acrylic polymer will react with the isocyanate group of the compound, and the ethylenically unsaturated group derived from the compound will be introduced into the acrylic polymer.
  • the amount of said other monomer is suitably approximately 1% by weight or more of the total monomer components, from the viewpoint of the thermosetting properties of the adhesive and adhesive properties such as cohesive strength, and is preferably approximately 5% by weight or more, more preferably approximately 10% by weight or more, and may be approximately 12% by weight or more.
  • the amount of said other monomer is suitably approximately 40% by weight or less of the total monomer components, and is preferably approximately 30% by weight or less, more preferably approximately 25% by weight or less, and may be approximately 20% by weight or less (for example, 15% by weight or less).
  • the acrylic polymer may contain, as another monomer component, a polyfunctional monomer having at least two ethylenically unsaturated groups, such as a (meth)acryloyl group or a vinyl group.
  • a polyfunctional monomer as a monomer component can increase the cohesive strength of the adhesive.
  • the polyfunctional monomer can be used as a crosslinking agent.
  • suitable polyfunctional monomers selected from the polyfunctional monomers exemplified below as blending monomers that can be included in the adhesive layer can be used alone or in combination.
  • the amount of polyfunctional monomer used is not particularly limited and can be appropriately set so as to achieve the intended purpose of using the polyfunctional monomer.
  • the amount of polyfunctional monomer used can be approximately 3% by weight or less of the above-mentioned monomer components, preferably approximately 2% by weight or less, and more preferably approximately 1% by weight or less (e.g., approximately 0.5% by weight or less).
  • the lower limit of the amount used is not particularly limited, as long as it is greater than 0% by weight.
  • the effects of using the polyfunctional monomer can be appropriately achieved by using an amount of polyfunctional monomer that is approximately 0.001% by weight or more (e.g., approximately 0.01% by weight or more) of the monomer components.
  • the method for obtaining the acrylic polymer is not particularly limited, and various polymerization methods known as methods for synthesizing acrylic polymers, such as solution polymerization, emulsion polymerization, bulk polymerization, suspension polymerization, and photopolymerization, can be used as appropriate.
  • solution polymerization is preferably used.
  • the monomer supply method for solution polymerization can be appropriately selected from a batch feed method in which all monomer raw materials are supplied at once, a continuous feed (dropping) method, a divided feed (dropping) method, and the like.
  • the polymerization temperature can be appropriately selected depending on the types of monomers and solvents used, the type of polymerization initiator, and the like, and can be, for example, approximately 20°C to 170°C (typically approximately 40°C to 140°C).
  • the solvent (polymerization solvent) used in solution polymerization can be appropriately selected from conventionally known organic solvents.
  • aromatic compounds typically aromatic hydrocarbons
  • acetate esters such as ethyl acetate
  • aliphatic or alicyclic hydrocarbons such as hexane or cyclohexane
  • halogenated alkanes such as 1,2-dichloroethane
  • lower alcohols e.g., monohydric alcohols having 1 to 4 carbon atoms
  • ethers such as tert-butyl methyl ether
  • ketones such as methyl ethyl ketone; etc.
  • the initiator used for polymerization can be appropriately selected from conventionally known polymerization initiators depending on the type of polymerization method.
  • azo-based polymerization initiators peroxide-based polymerization initiators, redox-based polymerization initiators formed by combining peroxides with reducing agents, and substituted ethane-based polymerization initiators can be used.
  • one or more polymerization initiators can be selected from those exemplified as thermal polymerization initiators added to the adhesive layer described below.
  • the amount of the polymerization initiator used can be a normal amount depending on the polymerization method, polymerization mode, etc., and is not particularly limited. For example, approximately 0.001 to 5 parts by weight (typically approximately 0.01 to 2 parts by weight, e.g., approximately 0.01 to 1 part by weight) of polymerization initiator can be used per 100 parts by weight of all monomer components to be polymerized.
  • the adhesive layer disclosed herein includes a polymer having an ethylenically unsaturated group as the polymer.
  • the ethylenically unsaturated group functions as a polymerizable functional group (typically a radically polymerizable functional group).
  • a suitable polymers can be selected from the various polymers (e.g., acrylic polymers) exemplified above and having an ethylenically unsaturated group.
  • the polymer having an ethylenically unsaturated group can be used as a base polymer in an adhesive.
  • the adhesive When an adhesive containing the polymer having an ethylenically unsaturated group reacts with the ethylenically unsaturated group during heat treatment, the adhesive can be thermally cured to a high degree, resulting in easy heat peelability. More specifically, when an adhesive is heated, for example at a high temperature while attached to an adherend, it usually adsorbs to the surface of the adherend. As a result, the adhesive strength of the adhesive to the adherend increases, resulting in heavy peelability.
  • the technology disclosed herein by incorporating a polymer having an ethylenically unsaturated group and a thermal polymerization initiator into the adhesive, the ethylenically unsaturated groups in the adhesive react (radical polymerization reaction) upon heating, allowing the adhesive to harden prior to adsorption to the adherend. This reduces the peel strength from the adherend. Furthermore, even if heating is continued thereafter, the peel strength of the adhesive from the adherend does not increase but is maintained within a predetermined range, allowing the adhesive to exhibit good heat-peelability.
  • the technology disclosed herein is not limited to the above considerations.
  • a pressure-sensitive adhesive containing a polymer having an ethylenically unsaturated group can achieve sufficient heat-peelability and heat-resistant heat-peelability without relying on the use of the compounded monomer described below, or while limiting the amount of compounded monomer used.
  • ethylenically unsaturated groups contained in the above polymer include, but are not limited to, acryloyl groups, methacryloyl groups, vinyl groups, and allyl groups.
  • Preferred examples of ethylenically unsaturated groups include acryloyl groups and methacryloyl groups.
  • a polymer having an ethylenically unsaturated group in a side chain is used as the polymer having an ethylenically unsaturated group.
  • the monomer component of the polymer having an ethylenically unsaturated group one or more of the monomer components exemplified for the above polymer can be used in the above content range.
  • the amount of ethylenically unsaturated groups in a polymer having ethylenically unsaturated groups is not particularly limited, but from the standpoint of thermosetting properties, etc., it is suitably 0.01 mmol per 1 g of polymer (hereinafter also referred to as mmol/g) or more, and may be 0.1 mmol/g or more, or 0.5 mmol/g or more. Furthermore, the amount of ethylenically unsaturated groups in the polymer is suitably 10.0 mmol/g or less, and may be 5.0 mmol/g or less, 3.0 mmol/g or less, 2.5 mmol/g or less, or 2.0 mmol/g or less.
  • the amount of ethylenically unsaturated groups in a polymer is measured by the following method, for example, when the ethylenically unsaturated groups are (meth)acryloyl groups.
  • 0.25 mg of the polymer to be measured is dissolved in 50 mL of THF (tetrahydrofuran), and 15 mL of methanol is added to obtain a solution.
  • 10 mL of 4N aqueous sodium hydroxide is added to the solution to obtain a mixed solution.
  • the mixed solution is stirred at a liquid temperature of 40°C for 2 hours.
  • 10.2 mL of 4N methanesulfonic acid solution is added to the mixed solution and stirred.
  • An example of a method for measuring the content of ethylenically unsaturated groups other than (meth)acryloyl groups is the method of measuring the bromine number in accordance with JIS K2605: 1996.
  • the content of ethylenically unsaturated groups other than (meth)acryloyl groups is determined by converting the number of grams of bromine ( Br2 ) added to 100 g of the polymer to be measured into the number of moles of bromine ( Br2 ) added to 1 g of the polymer.
  • the method for introducing an ethylenically unsaturated group into a polymer is not particularly limited, and an appropriate method can be selected from among methods known to those skilled in the art. From the perspective of molecular design, etc., a method of introducing an ethylenically unsaturated group into the side chain of a polymer is preferred. For example, a method of reacting (typically condensation or addition reaction) a compound having an ethylenically unsaturated group with a functional group (functional group B) that can react with the functional group (functional group A) introduced into the acrylic polymer by copolymerization, while preventing the ethylenically unsaturated group from disappearing, is preferably employed.
  • Examples of combinations of functional group A and functional group B include a combination of a carboxy group and an epoxy group, a combination of a carboxy group and an aziridyl group, and a combination of a hydroxyl group and an isocyanate group. Of these, a combination of a hydroxyl group and an isocyanate group is preferred from the perspective of reaction traceability. From the perspective of polymer design, etc., a combination in which the acrylic polymer has a hydroxyl group and the above compound has an isocyanate group is particularly preferred.
  • the compound having an ethylenically unsaturated group may have a functional group B that can react with functional group A.
  • Suitable examples of such compounds include isocyanate group-containing monomers (isocyanate group-containing compounds) such as 2-(meth)acryloyloxyethyl isocyanate. Of these, 2-(meth)acryloyloxyethyl isocyanate is more preferred.
  • An acrylic polymer having an ethylenically unsaturated group can be obtained by reacting the isocyanate group of the isocyanate group-containing compound having an ethylenically unsaturated group with the hydroxyl group of the acrylic polymer to form a bond (specifically a urethane bond).
  • the adhesive layer may contain a polymer that is substantially free of ethylenically unsaturated groups (a polymer in which the amount of ethylenically unsaturated groups is less than 0.01 mmol/g), to the extent that the effects of the technology disclosed herein are not impaired.
  • the amount of such a polymer that is substantially free of ethylenically unsaturated groups is suitably less than 50% by weight of the total polymer (specifically, base polymer) contained in the adhesive layer, and may be less than 30% by weight, less than 10% by weight, less than 3% by weight, or less than 1% by weight.
  • the adhesive layer may be substantially free of the above-mentioned polymer that is substantially free of ethylenically unsaturated groups.
  • the molecular weight of the polymer (e.g., acrylic polymer) is not particularly limited and can be set within an appropriate range depending on the required performance, etc.
  • the weight average molecular weight (Mw) of the polymer is suitably approximately 1 x 10 4 or more, for example, approximately 10 x 10 4 or more.
  • Mw weight average molecular weight
  • the Mw may be 20 x 10 4 or more, 30 x 10 4 or more, approximately 40 x 10 4 or more, approximately 50 x 10 4 or more, for example, approximately 55 x 10 4 or more.
  • the upper limit of the Mw of the polymer is not particularly limited, and may be, for example, approximately 1000 x 10 4 or less, or approximately 100 x 10 4 or less.
  • Mw refers to the value calculated in terms of standard polystyrene obtained by gel permeation chromatography (GPC).
  • GPC gel permeation chromatography
  • a model "HLC-8320GPC” columnumn: TSKgel GMH-H(S), manufactured by Tosoh Corporation) may be used.
  • the pressure-sensitive adhesive layer preferably contains a monomer (a compounded monomer) in addition to the polymer.
  • the monomer has an ethylenically unsaturated group.
  • the ethylenically unsaturated group of the monomer functions as a polymerizable functional group (typically a radically polymerizable functional group).
  • the monomer contained in the pressure-sensitive adhesive layer reacts quickly with the ethylenically unsaturated group of the polymer during heat treatment under specified conditions, and the pressure-sensitive adhesive is heat-cured to a high degree of cure, thereby exhibiting excellent heat-peelability.
  • a thermosetting pressure-sensitive adhesive that retains heat-resistant peelability even after heat treatment can be preferably obtained.
  • the above monomers can be used alone or in combination of two or more.
  • Examples of ethylenically unsaturated groups contained in the above-mentioned monomers include, but are not limited to, acryloyl groups, methacryloyl groups, vinyl groups, and allyl groups.
  • Preferred examples of ethylenically unsaturated groups include acryloyl groups and methacryloyl groups. Of these, acryloyl groups are preferred.
  • compounds containing acryloyl groups and/or methacryloyl groups may be referred to as acrylic monomers.
  • compounds containing vinyl groups may be referred to as vinyl monomers.
  • the molecular weight of the monomer may be, for example, 150 or more, 250 or more, 300 or more, 350 or more, 400 or more, 450 or more, or 500 or more.
  • the molecular weight of the monomer is typically approximately 100,000 or less, for example, approximately 10,000 or less (e.g., less than 10,000) is appropriate, and 5,000 or less (e.g., less than 5,000) is preferable, and may be 1,500 or less, 1,000 or less (e.g., less than 1,000), 800 or less, or 600 or less.
  • the use of the monomer with a molecular weight within the above range can be advantageous, for example, in terms of the ease of preparation and coatability of the pressure-sensitive adhesive composition.
  • the above molecular weight is the manufacturer's nominal value or a molecular weight calculated from the molecular structure.
  • the weight average molecular weight (Mw) calculated in terms of standard polystyrene obtained by GPC may be used.
  • the weight loss rate of the heat-resistant monomer upon heating at 180°C is 0.9% or less, more preferably 0.8% or less, even more preferably 0.7% or less, particularly preferably 0.6% or less, and may even be 0.5% or less.
  • the lower limit of the weight loss rate upon heating at 180°C of the heat-resistant monomer is theoretically 0%, and in practice may be 0.1% or more, 0.2% or more, or 0.3% or more.
  • Preferred heat-resistant monomers are trimethylolpropane triacrylate (TMPTA, weight loss rate at 180°C: 1%) and dipentaerythritol hexaacrylate (DPHA, weight loss rate at 180°C: 0.5%). These heat-resistant monomers can be used alone or in combination of two or more.
  • a polyfunctional monomer is used as the above-mentioned monomer.
  • a polyfunctional monomer refers to a polymerizable compound having two or more ethylenically unsaturated groups in one molecule, and includes compounds known as oligomers.
  • a compound having two or more acryloyl groups and/or methacryloyl groups may be referred to as a polyfunctional acrylic monomer.
  • a compound having two or more vinyl groups may be referred to as a polyfunctional vinyl monomer.
  • the number of ethylenically unsaturated groups contained in one molecule of the polyfunctional monomer may be 3 or more, preferably 4 or more, more preferably 5 or more, and may even be 6 or more.
  • the greater the number of ethylenically unsaturated groups in the polyfunctional monomer the better the curing properties during heat treatment and the easier it is to achieve heat-separable properties.
  • polyfunctional monomers with a greater number of ethylenically unsaturated groups (functional groups) can achieve heat-separable properties with relatively small amounts of use. This is advantageous because it also reduces the amount of outgassing derived from the polyfunctional monomer.
  • the upper limit of the number of ethylenically unsaturated groups in one molecule of the polyfunctional monomer is not limited to a specific range and may be, for example, 50 or less, 40 or less, 30 or less, 20 or less, or 15 or less. In some embodiments, the number of ethylenically unsaturated groups in one molecule of the polyfunctional monomer may be, for example, 10 or less, 8 or less, or 6 or less. Polyfunctional monomers with the above number of ethylenically unsaturated groups tend to achieve both good adhesion and heat-separable properties and also tend to have excellent storage stability.
  • polyfunctional monomer various polyfunctional acrylate monomers and polyfunctional vinyl monomers having two or more ethylenically unsaturated groups can be used.
  • polyfunctional acrylate monomers are preferably used.
  • polyfunctional acrylate monomers tend to be compatible and easily exhibit desired properties when used in combination with acrylic polymers.
  • Polyfunctional acrylate monomers and polyfunctional vinyl monomers can be used either alone or in combination of two or more.
  • Polyfunctional monomers include 1,6-hexanediol di(meth)acrylate, 1,12-dodecanediol di(meth)acrylate, ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, allyl (meth)acrylate, alkylene oxide-modified bisphenol A di(meth)acrylate, alkylene oxide-modified neopentyl glycol di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, dimethylol di
  • difunctional monomers such as trimethylolpropane tri(meth)acrylate, trimethylolpropane ethoxy tri(meth)acrylate, glycerin propoxy triacrylate, tetramethylolmethane tri(meth)acrylate, and pentaerythritol tri(meth)acrylate; tetrafunctional monomers such as pentaerythritol alkoxy tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, and pentaerythritol tetra(meth)acrylate Examples of suitable monomers include pentafunctional monomers such as sorbitol penta(meth)acrylate and dipentaerythritol penta(meth)acrylate; hexafunctional monomers such as dipentaerythritol hexa(meth)acrylate, sorbitol hexa(meth)acrylate, alkylene
  • the content of the polyfunctional monomer in the adhesive layer is not particularly limited.
  • the content of the polyfunctional monomer may be approximately 1 part by weight or more, or may be 3 parts by weight or more, per 100 parts by weight of the polymer (specifically, the base polymer, preferably an acrylic polymer) contained in the adhesive layer.
  • the amount of the polyfunctional monomer per 100 parts by weight of the polymer is suitably approximately 200 parts by weight or less, preferably 160 parts by weight or less, more preferably 150 parts by weight or less, and even more preferably 140 parts by weight or less. It may be 120 parts by weight or less, or even 90 parts by weight or less.
  • the amount of the polyfunctional monomer per 100 parts by weight of the polymer may be 70 parts by weight or less, 50 parts by weight or less (e.g., less than 50 parts by weight), 45 parts by weight or less (e.g., less than 45 parts by weight), 40 parts by weight or less, 35 parts by weight or less, 30 parts by weight or less, 25 parts by weight or less, or 20 parts by weight or less.
  • the desired heat-peelability can be preferably achieved with a composition in which the amount of the polyfunctional monomer in the pressure-sensitive adhesive layer is limited as described above.
  • the generation of low-molecular-weight components derived from the polyfunctional monomer after heating is suppressed, and contamination of the adherend surface caused by such low-molecular-weight components can be prevented.
  • the amount of the polyfunctional monomer relative to the total amount of the monomers is not particularly limited.
  • the amount of the polyfunctional monomer is suitably approximately 10% by weight or more of the total amount of the monomers, preferably 30% by weight or more, more preferably approximately 50% by weight or more (e.g., more than 50% by weight), even more preferably 70% by weight or more, even more preferably 90% by weight or more, particularly preferably 95% by weight or more, and may be 99 to 100% by weight.
  • the monomer contained in the pressure-sensitive adhesive composition may consist essentially of the polyfunctional monomer.
  • one or more monofunctional monomers containing one ethylenically unsaturated group per molecule may be used as the above-mentioned monomer.
  • Known monofunctional acrylate monomers and vinyl monomers can be used as the monofunctional monomer.
  • one or more of the acrylate monomers (alkoxy group-containing (meth)acrylates, linear alkyl (meth)acrylates, etc.) exemplified as monomer components of the above-mentioned polymer can be used.
  • the appropriate amount of the monomer may vary depending on its molecular weight, number of functional groups, etc., but in some preferred embodiments, from the perspective of improving heat-peelability, the content of the monomer is 5 parts by weight or more, 7 parts by weight or more, 8 parts by weight or more, or 9 parts by weight or more, more preferably 10 parts by weight or more (e.g., more than 10 parts by weight), more preferably 12 parts by weight or more, even more preferably 15 parts by weight or more, and even more preferably 18 parts by weight or more, per 100 parts by weight of the polymer contained in the adhesive layer.
  • the upper limit of the content of the monomer in the adhesive layer is not particularly limited and can be set to achieve the desired adhesive properties.
  • the pressure-sensitive adhesive layer contains a thermal polymerization initiator in addition to the polymer.
  • the thermal polymerization initiator refers to a polymerization initiator that generates radicals when heated.
  • the thermal polymerization initiator reacts with ethylenically unsaturated groups in the pressure-sensitive adhesive layer during heat treatment at a predetermined temperature or higher, thereby reducing the peel force and achieving heat-peelability.
  • a thermosetting pressure-sensitive adhesive that retains heat-resistant easy peelability even after heat treatment can be formed.
  • a peroxide-based polymerization initiator as the thermal polymerization initiator.
  • a peroxide-based polymerization initiator By incorporating a peroxide-based polymerization initiator into the adhesive layer, the curing reaction of the adhesive layer during heat treatment proceeds rapidly, making it easier to achieve excellent heat-peelability and heat-resistant peelability.
  • One reason for this is thought to be the high initiation efficiency of peroxide-based polymerization initiators (especially organic peroxide-based polymerization initiators).
  • peroxide-based polymerization initiators generate radicals (-O.) by cleaving the -O-O- moiety contained in the compound.
  • the thermal curing rate is faster than the rate at which heating causes the adhesive layer to firmly adhere to the adherend, it is believed that the post-heat peel force is effectively reduced, making it easier to achieve excellent heat-peelability and heat-resistant peelability.
  • the technology disclosed herein is not limited to the above considerations.
  • Peroxide-based polymerization initiators that are preferably used include organic peroxides such as diacyl peroxides, peroxyesters, peroxydicarbonates, monoperoxycarbonates, peroxyketals, dialkyl peroxides, hydroperoxides, and ketone peroxides.
  • organic peroxides such as diacyl peroxides, peroxyesters, peroxydicarbonates, monoperoxycarbonates, peroxyketals, dialkyl peroxides, hydroperoxides, and ketone peroxides.
  • Suitable examples of peroxide-based polymerization initiators include benzoyl peroxide compounds (typically dibenzoyl peroxide (BPO)) that have a benzoyl group that may have a substituent.
  • BPO dibenzoyl peroxide
  • Peroxide-based polymerization initiators can be used alone or in combination of two or more.
  • peroxide polymerization initiators include BPO, 1,1-di(t-hexylperoxy)cyclohexane, cyclohexanone peroxide, 3,3,5-trimethylcyclohexanone peroxide, methylcyclohexanone peroxide, 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(t-butylperoxy)cyclohexane, n-butyl-4,4-bis(t-butylperoxy)valerate, cumene hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide, and 1,3-bis(t-butylperoxy)-m-isopropyl Examples include diisopropylbenzene, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 2,5-dimethyl-2,5-di(t-butyl)he
  • the content of the peroxide-based polymerization initiator is suitably 0.1 parts by weight or more, preferably 0.2 parts by weight or more, more preferably 0.3 parts by weight or more, even more preferably 0.4 parts by weight or more, even more preferably 0.5 parts by weight or more, even more preferably 0.6 parts by weight or more, particularly preferably 0.7 parts by weight or more, and may even be 0.8 parts by weight or more, per 100 parts by weight of the polymer contained in the pressure-sensitive adhesive layer.
  • the amount of peroxide polymerization initiator per 100 parts by weight of the polymer may be, for example, about 10 parts by weight or less, or may be approximately 5 parts by weight or less.
  • the content of the peroxide-based polymerization initiator in the pressure-sensitive adhesive layer can also be determined by its relative relationship to the compounded monomer in the pressure-sensitive adhesive layer.
  • the amount of peroxide-based polymerization initiator per 100 parts by weight of the monomer is appropriately set to 0.1 parts by weight or more, from the viewpoint of increasing the frequency of collisions with the ethylenically unsaturated groups of the monomer to rapidly progress thermal curing and from the viewpoint of thermally curing the pressure-sensitive adhesive layer to a high degree of cure.
  • the amount is preferably 0.5 parts by weight or more, more preferably 1.0 parts by weight or more, even more preferably 2.0 parts by weight or more, even more preferably 2.5 parts by weight or more, and particularly preferably 3.0 parts by weight or more, and may even be 3.5 parts by weight or more.
  • the amount of the peroxide-based polymerization initiator used can be preferably used, for example, in compositions in which the content of the monomer is limited.
  • the amount of peroxide-based polymerization initiator per 100 parts by weight of the monomer may be, for example, approximately 20 parts by weight or less, 15 parts by weight or less, 12 parts by weight or less, or 10 parts by weight or less.
  • the amount of peroxide polymerization initiator per 100 parts by weight of the monomer may be 7 parts by weight or less, or may be 5 parts by weight or less.
  • the proportion of the peroxide-based polymerization initiator in the total thermal polymerization initiator contained in the adhesive layer may be approximately 10% by weight or more, suitably approximately 30% by weight or more, preferably 50% by weight or more, more preferably 70% by weight or more, even more preferably 90% by weight or more, and particularly preferably 95 to 100% by weight.
  • the thermal polymerization initiator contained in the adhesive layer may consist of a peroxide-based polymerization initiator.
  • a thermal polymerization initiator whose self-accelerating decomposition temperature (SADT) [°C] satisfies the formula: SADT + 10 ⁇ 60.
  • SADT self-accelerating decomposition temperature
  • the SADT of a thermal polymerization initiator is defined as the lowest temperature at which a certain amount of the initiator in a container generates heat of 6°C or more or self-accelerating decomposition within seven days.
  • SADT indicates the environmental temperature at which the thermal polymerization initiator decomposes.
  • the amount of thermal polymerization initiator contained in the adhesive layer is not particularly limited.
  • the content of the thermal polymerization initiator in the adhesive layer may be, for example, 0.01 parts by weight or more, or may be 0.05 parts by weight or more, per 100 parts by weight of the polymer (specifically, the base polymer, e.g., an acrylic polymer) contained in the adhesive layer.
  • the content of the thermal polymerization initiator in the adhesive layer is suitably 0.1 parts by weight or more, preferably 0.2 parts by weight or more, more preferably 0.3 parts by weight or more, even more preferably 0.4 parts by weight or more, even more preferably 0.5 parts by weight or more, even more preferably 0.6 parts by weight or more, particularly preferably 0.7 parts by weight or more, and may even be 0.8 parts by weight or more, per 100 parts by weight of the polymer contained in the adhesive layer.
  • the higher the content of the thermal polymerization initiator the greater the frequency of collisions between the thermal polymerization initiator and ethylenically unsaturated groups in the adhesive layer, making the curing reaction more likely to proceed.
  • the total proportion of the above-mentioned polymer (specifically, the base polymer, for example, an acrylic polymer), the above-mentioned monomer (for example, a polyfunctional acrylic monomer), and the thermal polymerization initiator (for example, a peroxide-based polymerization initiator) in the entire pressure-sensitive adhesive layer is suitably 50% by weight or more (for example, more than 50% by weight and 100% by weight or less), preferably 70% by weight or more, more preferably 80% by weight or more, and even more preferably 90% by weight or more, and may be 95% by weight or more, 98% by weight or more, or 99% by weight or more (for example, 99 to 100% by weight), from the perspective of effectively achieving a reduction in peel strength when heated.
  • the base polymer for example, an acrylic polymer
  • the above-mentioned monomer for example, a polyfunctional acrylic monomer
  • the thermal polymerization initiator for example, a peroxide-based polymerization initiator
  • isocyanate-based crosslinking agents epoxy-based crosslinking agents, oxazoline-based crosslinking agents, aziridine-based crosslinking agents, and carbodiimide-based crosslinking agents are preferred, with isocyanate-based crosslinking agents being particularly preferred.
  • a polyfunctional isocyanate compound with two or more functionalities can be used.
  • aromatic isocyanates such as tolylene diisocyanate, xylene diisocyanate, polymethylene polyphenyl diisocyanate, tris(p-isocyanatophenyl)thiophosphate, and diphenylmethane diisocyanate
  • alicyclic isocyanates such as isophorone diisocyanate
  • aliphatic isocyanates such as hexamethylene diisocyanate.
  • isocyanate adducts such as trimethylolpropane/tolylene diisocyanate trimer adduct (manufactured by Tosoh Corporation, trade name “Coronate L”), trimethylolpropane/hexamethylene diisocyanate trimer adduct (manufactured by Tosoh Corporation, trade name “Coronate HL”), hexamethylene diisocyanate isocyanurate (manufactured by Tosoh Corporation, trade name “Coronate HX”), and trimethylolpropane/xylylene diisocyanate adduct (manufactured by Mitsui Chemicals, Inc., trade name "Takenate D-110N”).
  • isocyanate adducts such as trimethylolpropane/tolylene diisocyanate trimer adduct (manufactured by Tosoh Corporation, trade name “Coronate L”), trimethylolpropane
  • epoxy crosslinking agents include Mitsubishi Gas Chemical Company, Inc.'s “Tetrad-X” and “Tetrad-C” products, DIC Corporation's “Epicron CR-5L” product, Nagase ChemteX Corporation's “Denacol EX-512” product, and Nissan Chemical Industries, Ltd.'s "TEPIC-G” product.
  • an isocyanate-based crosslinking agent is used as the crosslinking agent.
  • Isocyanate-based crosslinking agents facilitate the formation of a PSA that exhibits a good balance of adhesive properties, such as adhesive strength and cohesive strength, while also exhibiting good heat-peelability.
  • Isocyanate-based crosslinking agents can be used alone or in combination with two or more. While not particularly limited, the amount used when an isocyanate-based crosslinking agent is used is preferably less than 3 parts by weight per 100 parts by weight of the polymer (specifically, the base polymer, e.g., an acrylic polymer) contained in the PSA layer.
  • the crosslinking density is appropriately suppressed.
  • the amount of isocyanate-based crosslinking agent used per 100 parts by weight of the polymer is 2 parts by weight or less, more preferably 1.5 parts by weight or less, even more preferably 1.0 part by weight or less, even more preferably 0.8 parts by weight or less, and particularly preferably 0.6 parts by weight or less.
  • the amount of crosslinking agent used may be greater than 0 parts by weight, for example, 0.001 parts by weight or more, or even 0.01 parts by weight or more, per 100 parts by weight of the polymer (specifically, the base polymer, e.g., an acrylic polymer) contained in the adhesive layer, from the viewpoint of realizing an adhesive that exhibits a well-balanced adhesive property, such as adhesive strength and cohesive strength.
  • the amount of crosslinking agent used per 100 parts by weight of the polymer may be 0.05 parts by weight or more, 0.1 parts by weight or more, 0.3 parts by weight or more, or 0.5 parts by weight or more.
  • the amount of crosslinking agent used is suitably less than 10 parts by weight per 100 parts by weight of the polymer, and in some embodiments, it is preferably less than 5 parts by weight, and may be less than 3 parts by weight. In some embodiments, the amount of crosslinking agent used is suitably less than 1 part by weight per 100 parts by weight of the polymer, and is preferably 0.9 parts by weight or less, or may be 0.8 parts by weight or less, 0.7 parts by weight or less, 0.6 parts by weight or less, or 0.5 parts by weight or less. By limiting the amount of crosslinking agent used, sufficient adhesive strength tends to be more easily obtained.
  • the amount of crosslinking catalyst used can be, for example, approximately 0.0001 part by weight or more, approximately 0.001 part by weight or more, or approximately 0.005 part by weight or more, per 100 parts by weight of the polymer (specifically, the base polymer, e.g., an acrylic polymer) contained in the adhesive layer, and can also be approximately 1 part by weight or less, approximately 0.1 part by weight or less, or approximately 0.05 part by weight or less.
  • the PSA composition used to form the PSA layer may optionally contain a compound that undergoes keto-enol tautomerization as a crosslinking retarder.
  • a compound that undergoes keto-enol tautomerization may be preferably used in a PSA composition containing an isocyanate-based crosslinking agent or a PSA composition that can be used by blending an isocyanate-based crosslinking agent. This can exert the effect of extending the pot life of the PSA composition.
  • various ⁇ -dicarbonyl compounds can be used as the compound that undergoes keto-enol tautomerization.
  • ⁇ -diketones such as acetylacetone and 2,4-hexanedione
  • acetoacetate esters such as methyl acetoacetate and ethyl acetoacetate
  • propionylacetate esters such as ethyl propionylacetate
  • isobutyrylacetate esters such as ethyl isobutyrylacetate
  • malonate esters such as methyl malonate and ethyl malonate.
  • acetylacetone and acetoacetate esters are preferred.
  • the compound that undergoes keto-enol tautomerization can be used alone or in combination of two or more.
  • the pressure-sensitive adhesive layer may contain, as necessary, various additives commonly used in the field of pressure-sensitive adhesives, such as tackifiers, silane coupling agents, release force modifiers (surfactants, etc.), viscosity modifiers (e.g., thickeners), leveling agents, plasticizers, fillers, colorants such as pigments and dyes, stabilizers, preservatives, antioxidants, etc.
  • various additives such as tackifiers, silane coupling agents, release force modifiers (surfactants, etc.), viscosity modifiers (e.g., thickeners), leveling agents, plasticizers, fillers, colorants such as pigments and dyes, stabilizers, preservatives, antioxidants, etc.
  • tackifiers silane coupling agents
  • release force modifiers surfactants, etc.
  • viscosity modifiers e.g., thickeners
  • leveling agents e.g., plasticizers, fillers, colorants such as pigments and dyes
  • the PSA layer disclosed herein can be preferably formed using a solvent-based PSA composition.
  • the solvent-based PSA composition is a PSA composition in the form of PSA-forming components in an organic solvent.
  • the solvent-based PSA composition typically contains a solution polymer of a monomer component, a thermal polymerization initiator (specifically, a peroxide-based polymerization initiator), and optionally other additives.
  • the effects of the technology disclosed herein can be effectively achieved in a form comprising a solvent-based PSA (layer).
  • the solvent contained in the solvent-based PSA composition can be appropriately selected from conventionally known organic solvents.
  • any one solvent or a mixture of two or more solvents selected from aromatic compounds such as toluene; esters such as ethyl acetate and butyl acetate; aliphatic or alicyclic hydrocarbons such as hexane and cyclohexane; halogenated alkanes such as 1,2-dichloroethane; lower alcohols (e.g., monohydric alcohols having 1 to 4 carbon atoms) such as isopropyl alcohol; ethers such as tert-butyl methyl ether; and ketones such as methyl ethyl ketone can be used.
  • aromatic compounds typically aromatic hydrocarbons
  • esters such as ethyl acetate and butyl acetate
  • aliphatic or alicyclic hydrocarbons such as hexane and cyclohexane
  • halogenated alkanes such as 1,2-dichloroethane
  • lower alcohols e.g., monohydr
  • the pressure-sensitive adhesive layer disclosed herein can be formed by a conventionally known method. After applying (e.g., coating) the pressure-sensitive adhesive composition to a suitable surface, a curing treatment can be appropriately performed to form the pressure-sensitive adhesive in the form of a layer (pressure-sensitive adhesive layer).
  • the pressure-sensitive adhesive composition may be cured by one method (e.g., drying, crosslinking, polymerization, cooling, etc.), or by two or more methods simultaneously or in multiple stages.
  • the pressure-sensitive adhesive can typically be formed by drying (preferably further crosslinking) the composition.
  • a method can be employed in which a pressure-sensitive adhesive composition is applied to a surface (release surface) having releasability, and then the pressure-sensitive adhesive composition is cured to form a pressure-sensitive adhesive layer on the surface.
  • a substrate-attached pressure-sensitive adhesive sheet can be produced by transferring the pressure-sensitive adhesive layer formed on the release surface to a substrate (specifically, the surface of a resin layer formed on the substrate).
  • a method directly method can be employed in which the pressure-sensitive adhesive composition is directly applied (typically coated) to a substrate (specifically, the surface of a resin layer formed on the substrate) and cured to form a pressure-sensitive adhesive layer.
  • the pressure-sensitive adhesive composition can be applied using a known or commonly used coater such as a gravure roll coater, a reverse roll coater, a kiss roll coater, a dip roll coater, a die coater, a bar coater, a knife coater, a spray coater, etc.
  • a known or commonly used coater such as a gravure roll coater, a reverse roll coater, a kiss roll coater, a dip roll coater, a die coater, a bar coater, a knife coater, a spray coater, etc.
  • the pressure-sensitive adhesive composition may be applied by impregnation, curtain coating, or the like.
  • the pressure-sensitive adhesive composition is preferably dried under heating.
  • the drying temperature is not particularly limited, but can be, for example, about 40 to 100°C, and is usually preferably about 60 to 80°C.
  • drying at the above temperatures e.g., about 1 to 10 minutes, more specifically, about 3 to 7 minutes
  • the solvent volatilizes, so that, for example, in a pressure-sensitive adhesive composition containing a monomer or a thermal polymerization initiator, the reaction of the monomer or the deactivation of the thermal polymerization initiator is negligible.
  • the pressure-sensitive adhesive composition may be further aged for the purposes of adjusting the migration of components within the pressure-sensitive adhesive layer, promoting the crosslinking reaction, and alleviating distortion that may exist in the substrate or the pressure-sensitive adhesive layer.
  • the thickness of the pressure-sensitive adhesive layer is not particularly limited.
  • the thickness of the pressure-sensitive adhesive layer is usually 1 ⁇ m or more, and may be 2 ⁇ m or more, or 3 ⁇ m or more. The thicker the pressure-sensitive adhesive layer, the more the adhesive strength to the adherend tends to improve. In some preferred embodiments, the thickness of the pressure-sensitive adhesive layer is 5 ⁇ m or more, may be 10 ⁇ m or more, may be 15 ⁇ m or more, may be 20 ⁇ m or more, or may be 25 ⁇ m or more.
  • the upper limit of the thickness of the pressure-sensitive adhesive layer is, for example, suitably about 200 ⁇ m or less, may be 100 ⁇ m or less (e.g., less than 100 ⁇ m), or may be 50 ⁇ m or less. Limiting the thickness of the pressure-sensitive adhesive layer within a predetermined range tends to prevent the occurrence of adhesive residue due to cohesive failure and to easily obtain peelability. In addition, a thin pressure-sensitive adhesive layer is advantageous in terms of thinning the pressure-sensitive adhesive sheet, and also tends to have excellent conformability to the adherend. In some preferred embodiments, the thickness of the pressure-sensitive adhesive layer is 40 ⁇ m or less, or may be 30 ⁇ m or less.
  • a heat-resistant substrate (layer) is used as the substrate (layer) supporting (backing) the pressure-sensitive adhesive layer.
  • a substrate (layer) with a predetermined heat resistance can maintain its performance even after high-temperature heat treatment, such as 200°C or higher, without shrinkage or other deformation, or with only a small degree of deformation.
  • the anchoring properties of the pressure-sensitive adhesive layer can be well maintained during peeling after heat treatment.
  • the heat-resistant substrate (layer) preferably has a heat shrinkage rate of less than 1% in a heat shrinkage test performed under heating conditions of 200°C for 10 minutes in accordance with Clause 25 of JIS C2151:2019.
  • Preferably used resin films include polyester films, polyamide resin films, and engineering plastic films.
  • specific examples of the engineering plastic films include resin films formed from one or more engineering plastics (which may be super engineering plastics), such as polyethylene naphthalate (PEN), polyphenylene sulfide resins, polyethersulfone resins, polyetheretherketone resins, polyetherketone resins, polyphthalamide resins, polyarylate resins, polyamideimide resins, polyimide (PI) resins, and polyetherimide resins.
  • Engineering plastics are preferred from the standpoint of heat resistance.
  • resin films composed of polyester films (e.g., PEN films) and PI resin films are preferably used as heat-resistant substrates.
  • the pressure-sensitive adhesive sheet can be peeled from the adherend with the pressure-sensitive adhesive layer remaining well anchored.
  • the upper limit of the heat treatment temperature varies depending on the purpose of the heat treatment, the heat resistance of the adherend, etc., but is generally about 280°C or less, and may be about 260°C or less, about 250°C or less, 230°C or less, 200°C or less, or 180°C or less.
  • the heat treatment time is not particularly limited and may be within 10 hours, 5 hours or less, or 3 hours or less.
  • the heat treatment time may be within 1 hour, 30 minutes or less, 15 minutes or less, 10 minutes or less, or 5 minutes or less.
  • the pressure-sensitive adhesive sheet disclosed herein the pressure-sensitive adhesive may be thermally cured by the above-mentioned short-term heat treatment, thereby exhibiting heat-peelability.
  • the heat treatment time may be 1 minute or more, 3 minutes or more, 5 minutes or more, 7 minutes or more, or 9 minutes or more.
  • the heat treatment time may be 10 minutes or more, 30 minutes or more, 60 minutes or more, more than 1 hour, more than 3 hours, more than 4 hours, or more than 5 hours.
  • Heat treatment at the above-mentioned heating temperatures in the PSA sheet disclosed herein thermally cures the adhesive, reducing the peel strength, and even if the heated state continues for a long period of time, an increase in peel strength (heavy peeling) does not occur or can be suppressed. Therefore, it is possible to maintain easy heat releasability (heat-resistant easy peelability) even after long-term heat treatment.
  • Applications for the adhesive sheets disclosed herein include, for example, masking applications, temporary fixing applications, and protective applications, which require heat resistance from the adhesive sheet. They can also be preferably used as process materials that are fixed to and peeled off from adherends during the manufacturing process of electronic devices and electronic components. Suitable applications for the adhesive sheets disclosed herein include semiconductor device manufacturing applications. For example, they can be preferably used as wafer fixation sheets that fix wafers to fixation plates during semiconductor wafer processing (typically silicon wafer processing). For example, they can be preferably used as process materials that are peeled off from semiconductor wafers after processing while the semiconductor wafer is held by an adhesive layer. The adhesive sheets disclosed herein can also be preferably used as protective sheets that protect wafers during the wafer processing.
  • the adhesive sheet disclosed herein can be used to secure or protect various components or materials.
  • the adherend material can be made of an organic material, an inorganic material, or a composite of these.
  • adherend materials include glass such as alkali glass and alkali-free glass; metal materials such as stainless steel (SUS) and aluminum; ceramic materials such as alumina and silica; and resin materials such as polyester resins such as polyethylene terephthalate (PET), acrylic resins, ABS resins, polycarbonate resins, polystyrene resins, transparent polyimide resins, epoxy resins, and phenolic resins.
  • Suitable examples of adherend materials include circuit boards with a surface made of epoxy resin (e.g., glass cloth-based epoxy resin copper-clad laminates).
  • Other suitable examples of adherend materials include glass materials such as alkali glass and semiconductor wafers.
  • the glass material may be, for example, a glass plate having a surface partially covered with a transparent conductive film (e.g., an ITO (indium tin oxide) film) or an FPC (flexible printed circuit board), such as those used in tablet computers, mobile phones, organic LEDs (light-emitting diodes), etc.
  • a transparent conductive film e.g., an ITO (indium tin oxide) film
  • FPC flexible printed circuit board
  • the adhesive sheet disclosed herein can be preferably used in processing an adherend using the adhesive sheet
  • this specification provides, for example, a method including a processing step of processing an adherend to which the adhesive sheet disclosed herein has been attached.
  • a method of processing an adherend can be referred to as a method of processing an adherend, and can be a method of using an adhesive sheet in processing the adherend.
  • Adherends that can be used include the various adherends exemplified above, as well as workpieces and components composed of various adherend materials. These are also referred to as objects to be processed before the processing step, and as processed products after the processing step. Suitable examples of adherends include the above-mentioned semiconductor wafers, optical components, circuit boards, and other various substrates.
  • the above-mentioned method may further include a peeling step of peeling the adhesive sheet from the adherend after the above-mentioned processing step.
  • the adhesive sheet disclosed herein has good anchoring properties in the adhesive layer and is less likely to contaminate the adherend surface during peeling, making it suitable for various methods that include a peeling step such as the above-mentioned.
  • the above-mentioned method may include a step of preparing the adhesive sheet and the adherend, or a step of attaching the adhesive sheet to the adherend, prior to the above-mentioned processing step.
  • the resin layer-formed surface of the PI film was bonded to the pressure-sensitive adhesive layer obtained above, and then aging was carried out for 3 days at 50°C. In this way, a pressure-sensitive adhesive sheet (single-sided pressure-sensitive adhesive sheet with a substrate) according to this example was produced. The adhesive surface of the pressure-sensitive adhesive sheet was protected by a release liner.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Manufacturing & Machinery (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Adhesives Or Adhesive Processes (AREA)

Abstract

L'invention concerne une feuille adhésive qui est facile à libérer avec de la chaleur et dans laquelle une couche adhésive a de bonnes propriétés d'ancrage même après avoir subi un traitement thermique à haute température. Une feuille adhésive selon la présente invention comprend, dans cet ordre, une couche de matériau de base, une couche de résine et une couche adhésive. La couche de résine a une surface en contact avec la couche de matériau de base et une autre surface en contact avec la couche adhésive. La couche adhésive contient un polymère A et un initiateur de polymérisation thermique. Le polymère A contient un groupe éthyléniquement insaturé. La teneur en initiateur de polymérisation thermique dans la couche adhésive n'est pas inférieure à 0,01 partie en poids, par rapport à 100 parties en poids du polymère. La couche de matériau de base a un retrait thermique inférieur à 1 % tel que mesuré dans un test de retrait thermique dans lequel le chauffage est effectué à 200 °C pendant 10 minutes. La couche de résine contient un composé à base d'époxy et un polymère B qui contient un groupe amine. La teneur du composé à base d'époxy est de 1 à 15 parties en poids, par rapport à 100 parties en poids du polymère B.
PCT/JP2025/011484 2024-03-29 2025-03-24 Feuille adhésive, structure, procédé de production de structure et procédé Pending WO2025205624A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2024-056872 2024-03-29
JP2024056872 2024-03-29

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WO2025205624A1 true WO2025205624A1 (fr) 2025-10-02

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07133467A (ja) * 1993-11-10 1995-05-23 Sekisui Chem Co Ltd アクリル系粘着テープ
WO2014061774A1 (fr) * 2012-10-19 2014-04-24 リンテック株式会社 Feuille adhésive destinée au traitement de composants électroniques et procédé de fabrication de dispositif à semi-conducteur
JP2018009050A (ja) * 2016-07-11 2018-01-18 日東電工株式会社 粘着シート
WO2022185610A1 (fr) * 2021-03-05 2022-09-09 日東電工株式会社 Feuille adhésive double face équipée de doublure
WO2024024860A1 (fr) * 2022-07-28 2024-02-01 日東電工株式会社 Feuille adhésive sensible à la pression et procédé d'élimination de feuille adhésive sensible à la pression

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07133467A (ja) * 1993-11-10 1995-05-23 Sekisui Chem Co Ltd アクリル系粘着テープ
WO2014061774A1 (fr) * 2012-10-19 2014-04-24 リンテック株式会社 Feuille adhésive destinée au traitement de composants électroniques et procédé de fabrication de dispositif à semi-conducteur
JP2018009050A (ja) * 2016-07-11 2018-01-18 日東電工株式会社 粘着シート
WO2022185610A1 (fr) * 2021-03-05 2022-09-09 日東電工株式会社 Feuille adhésive double face équipée de doublure
WO2024024860A1 (fr) * 2022-07-28 2024-02-01 日東電工株式会社 Feuille adhésive sensible à la pression et procédé d'élimination de feuille adhésive sensible à la pression

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