JP2015025118A - Adhesive composition and adhesive film using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive composition which can be easily re-stuck, has no floating or peeling after being stuck to an adherend, and further has excellent detachability without change of adhesive strengh even under high temperature environment, and therefore can reduce pollution of the adherend by adhesive residue or the like.SOLUTION: An adhesive composition contains an acryl resin, an epoxy thermosetting resin and a curing agent for curing the epoxy thermosetting resin, and the epoxy thermosetting resin is contained at 20 to 60 mass% to the acryl resin.

Description

  The present invention relates to a pressure-sensitive adhesive composition, and more specifically, it can be easily re-applied, does not cause floating or peeling, and does not cause adhesive residue even when peeled after being placed in a high-temperature environment. The present invention relates to an adhesive composition and an adhesive film using the same.

  Electronic boards, wiring boards, and the like used in various electronic devices are manufactured through various processes such as mounting of electronic components on the board, lead frame manufacturing, soldering, and heat treatment. In these processes, a protective film that can be peeled off from the surface of the board to protect the mounted electrical components or prevent paint or solder from adhering to locations other than the desired location during lead frame processing or soldering. The protective film is peeled off after work. Such a protective film has a layer structure in which a pressure-sensitive adhesive layer is provided on one surface of a film substrate, and the protective film is bonded to an electronic substrate or the like that is an adherend. Bonded to the adherend.

  The protective film as described above needs to be in close contact with the substrate without being lifted or peeled off in each step of manufacturing an electronic substrate or a wiring substrate. On the other hand, when using a protective film with high adhesive strength so that it does not float or peel, some electronic substrates have extremely thin ones, and when peeling the protective film from such an electronic substrate with low self-supporting property, There is a problem that the electronic substrate itself is damaged. For example, as a pressure-sensitive adhesive for dicing tape used in the manufacture of semiconductor chips, Japanese Patent Application Laid-Open No. 2008-1992917 uses a free epoxy group-containing compound instead of an epoxy curing agent added to an acrylic pressure-sensitive adhesive. Proposed. According to this publication, by using a free epoxy group-containing compound, it is possible to prevent the pressure-sensitive adhesive from being cured and increase the adhesive strength with the adherend, and the pressure-sensitive adhesive is bonded to the adherend. It is taught that the pick-up property (peelability) is improved because the free epoxy group-containing compound later exudes to the interface between the pressure-sensitive adhesive body and the adherend.

  In addition, in the international publication WO2011 / 115159 pamphlet, an epoxy resin, a curing agent for epoxy resin, and a glass transition temperature of 60 ° C. or higher are used as a dicing tape capable of improving the bonding reliability between a semiconductor chip and an adherend. It has been proposed to use, as an adhesive, a curable composition containing two epoxy group-containing acrylic resins having different molecular weights.

  In addition, when a protective film is bonded to an electronic substrate or circuit board that is an adherend, the adhesive strength between the adhesive and the adherend increases after a heat treatment or the like, and the protective film is attached to the substrate. When peeled off, a part of the pressure-sensitive adhesive remains on the substrate and contaminates the substrate, so-called adhesive residue may occur. In order to solve such a problem, JP 2012-70112 A discloses that a chain containing a cyclic ether group-containing monomer is graft-polymerized as an acrylic adhesive as a heat-resistant adhesive that hardly causes adhesive residue ( It has been proposed to use a product obtained by adding a curing agent to a (meth) acrylic polymer. JP 2013-040323 A discloses a protective sheet having both adhesiveness and adhesive residue, and therefore, as an adhesive, a gel fraction is 60% or more, and an alkyl ester having 6 or more carbon atoms is used. It has been proposed to use an acrylic polymer consisting of a monomer having the same.

JP 2008-1992917 A International publication WO2011 / 115159 pamphlet JP2012-7012A JP2013-040323A

  Although the pressure-sensitive adhesive described in Japanese Patent Application Laid-Open No. 2008-192917 is excellent in releasability, it contains an epoxy group-containing compound as a free component in the pressure-sensitive adhesive, so that it contains an epoxy group on the adherend surface even after the pressure-sensitive adhesive is peeled off. In some cases, the compound remained and contaminated the substrate as the adherend.

  In addition, the adhesive described in International Publication WO2011 / 115159 pamphlet uses an epoxy resin having an epoxy group having a glass transition temperature of 60 ° C. or higher, so that the cohesive force is large. The acrylic resin having a group is difficult to peel off after being bonded to an adherend because the curing reaction proceeds and the adhesiveness is developed in a high temperature environment such as heat treatment.

  In addition, the pressure-sensitive adhesive described in Japanese Patent Application Laid-Open No. 2012-70112 does not increase the adhesive force even when the pressure-sensitive adhesive is placed in a high-temperature environment such as heat treatment. Although contamination (residue residue) can be reduced, it is difficult to adjust the adhesion with the adherend because the chain containing the cyclic ether group-containing monomer is graft-polymerized (meth) acrylic polymer, Depending on the type of adherend to which the masking tape (adhesive sheet) is bonded, there may be cases where floating or peeling occurs.

  Furthermore, since the adhesive described in JP2013-040323A does not contain a component (high glass transition temperature component) having a larger cohesive force than the acrylic resin, the adhesive strength under a high temperature environment becomes insufficient. There was a case.

  The inventors of the present invention have recently achieved the initial adhesive strength by using, as an adhesive, a resin obtained by adding a predetermined amount of an epoxy thermosetting resin and a curing agent to an acrylic resin and curing the epoxy thermosetting resin. Low, so it can be easily reattached even if it is a thin film-like adherend that does not have self-supporting properties, and it does not float or peel off after being attached to the adherend. Even when placed underneath, the adhesive strength did not change and it had excellent peelability, so that it was possible to reduce the contamination of the adherend due to adhesive residue and the like. In addition, chemical resistance is improved by using a thermosetting epoxy resin as an epoxy resin, and not only in the heating process, but also in the chemical treatment process, it can suppress floating and peeling after bonding to the adherend. I got the knowledge. The present invention is based on this finding.

  Therefore, the object of the present invention is that the initial adhesive force is low, so that even a thin film-like adherend having no self-supporting property can be easily reattached. Even if it is treated, it does not float or peel off, and even when it is placed in a high temperature environment, it has excellent peelability without changing the adhesive force. It is an object to provide a pressure-sensitive adhesive composition that can reduce contamination of a body and a pressure-sensitive adhesive sheet using the same.

The pressure-sensitive adhesive composition according to the present invention is a pressure-sensitive adhesive composition comprising an acrylic resin, an epoxy thermosetting resin, and a curing agent for curing the epoxy thermosetting resin,
The epoxy thermosetting resin is contained in an amount of 20 to 60% by mass with respect to the acrylic resin.

  Moreover, in the embodiment of this invention, the epoxy equivalent of the said epoxy thermosetting resin is 100-2000 g / eq. It is preferable that

  Moreover, in the embodiment of this invention, it is preferable that the mass mean molecular weights of the said epoxy thermosetting resin are 300-5000.

  Moreover, in the embodiment of this invention, it is preferable that the mass mean molecular weights of the said acrylic resin are 100,000-2 million.

The pressure-sensitive adhesive sheet according to another embodiment of the present invention is a pressure-sensitive adhesive sheet comprising a base material and a pressure-sensitive adhesive layer provided on one surface side of the base material, wherein the pressure-sensitive adhesive layer is an acrylic sheet. Comprising a resin and an epoxy thermosetting resin,
The epoxy thermosetting resin is contained in an amount of 20 to 60% by mass with respect to the acrylic resin.

  In the embodiment of the present invention, it is preferable that a release sheet is provided on the surface of the pressure-sensitive adhesive layer opposite to the substrate.

A method for producing a pressure-sensitive adhesive sheet according to another embodiment of the present invention is a method for producing a pressure-sensitive adhesive sheet comprising a base material and a pressure-sensitive adhesive layer provided on one surface side of the base material,
Apply the adhesive composition on one side of the substrate,
Forming a pressure-sensitive adhesive layer by heating and curing the pressure-sensitive adhesive composition;
Comprising
The pressure-sensitive adhesive composition comprises an acrylic resin, an epoxy thermosetting resin, and a curing agent for curing the epoxy thermosetting resin,
The epoxy thermosetting resin is contained in an amount of 20 to 60% by mass with respect to the acrylic resin.

In an embodiment of the present invention, the pressure-sensitive adhesive composition is applied to one side of the substrate and dried,
A release sheet is provided on the surface of the pressure-sensitive adhesive composition to form a laminate,
The pressure-sensitive adhesive layer is formed by heating the laminate and curing the pressure-sensitive adhesive composition.
It is preferable to comprise.

  According to the present invention, the initial adhesive force is low by using, as an adhesive, a resin obtained by adding a predetermined amount of an epoxy thermosetting resin and a curing agent to the acrylic resin and curing the epoxy thermosetting resin. Therefore, even thin film adherends that are not self-supporting can be easily reattached, and after bonding to the adherend, there is no lifting or peeling, and in a high temperature environment. Even when it is placed, the adhesive force does not change and has excellent releasability, so that contamination of the adherend due to adhesive residue and the like can be reduced. In addition, the pressure-sensitive adhesive composition according to the present invention is excellent in chemical resistance because it contains an epoxy thermosetting resin. Therefore, even if chemical treatment is performed after bonding to an adherend, floating or peeling occurs. There is nothing. Furthermore, since the pressure-sensitive adhesive composition according to the present invention does not contain a silicone pressure-sensitive adhesive and is silicone-free, it can be used as a pressure-sensitive adhesive sheet (masking sheet) for various electronic devices.

<Adhesive composition>
The pressure-sensitive adhesive composition according to the present invention contains an acrylic resin, an epoxy thermosetting resin, and a curing agent as essential components. Hereinafter, each component which comprises an adhesive composition is demonstrated.

<Acrylic resin>
The acrylic resin which comprises the adhesive composition by this invention can use suitably the acrylic resin which has (meth) acrylic acid ester as a main component. In addition, in this specification, (meth) acrylic acid shall mean acrylic acid and / or methacrylic acid. Examples of (meth) acrylic acid esters include methyl ester, ethyl ester, propyl ester, isopropyl ester, butyl ester, isobutyl ester, s-butyl ester, t-butyl ester, pentyl ester, isopentyl ester, hexyl ester, heptyl ester, Octyl ester, 2-ethylhexyl ester, isooctyl ester, nonyl ester, isononyl ester, decyl ester, isodecyl ester, undecyl ester, dodecyl ester, tridecyl ester, tetradecyl ester, hexadecyl ester, octadecyl ester, eicosyl (Meth) acrylic acid alkyl esters such as esters having 1 to 30 carbon atoms, in particular linear or branched alkyl esters having 1 to 18 carbon atoms, and (Meth) acrylic acid cycloalkyl esters such as clopentyl ester and cyclohexyl ester can be used. These acrylic acid esters may contain 1 type (s) or 2 or more types.

  In the present invention, for the purpose of modifying cohesive force, heat resistance, etc., other monomers or oligomers may be included as a copolymerization component as necessary. In addition to the above (meth) acrylic acid ester, You may use what copolymerized the monomer or oligomer which is mentioned later. For example, as the functional group-containing (meth) acrylate copolymerizable with the above (meth) acrylic acid ester, acrylic acid, methacrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid , Carboxyl group-containing monomers such as fumaric acid and crotonic acid, acid anhydride group-containing monomers such as maleic anhydride and itaconic anhydride, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, ( 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, ( 4-hydroxymethylcyclohexyl) me Hydroxyl group-containing monomers such as ru (meth) acrylate, N-methylol (meth) acrylamide, vinyl alcohol, allyl alcohol, 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, diethylene glycol monovinyl ether, styrene sulfonic acid, allyl sulfonic acid, Sulfonic acid group-containing monomers such as 2- (meth) acrylamide-2-methylpropanesulfonic acid, (meth) acrylamidepropanesulfonic acid, sulfopropyl (meth) acrylate, (meth) acryloyloxynaphthalenesulfonic acid, 2-hydroxyethylacryloyl Phosphate group-containing monomers such as phosphate, epoxy group-containing monomers such as glycidyl (meth) acrylate and allyl glycidyl ether, vinyl ethers such as vinyl acetate Ethers, aromatic vinyl compounds such as styrene, and, like ether and vinyl ethyl ether.

  In addition, monomers containing nitrogen atoms such as cyano group-containing monomers such as acrylonitrile, amide group-containing monomers such as acrylamide, amino group-containing monomers such as N, N-dimethylaminoethyl (meth) acrylate, and isocyanate group-containing monomers are also used. It may be used as a polymerization component.

  The acrylic resin (copolymer) used in the present invention can be obtained by polymerizing the above monomers by a method such as ordinary solution polymerization, bulk polymerization, emulsion polymerization or suspension polymerization. The acrylic resin is preferably produced by solution polymerization obtained as a solution. By obtaining the acrylic resin as a solution, it can be used as it is for producing the pressure-sensitive adhesive composition of the present invention.

  Examples of the solvent used for the solution polymerization include organic solvents such as ethyl acetate, toluene, n-hexane, acetone, and methyl ethyl ketone. Examples of the polymerization initiator used in the polymerization include peroxides such as benzoyl peroxide and lauryl peroxide, azobis compounds such as azobisisobutyronitrile and azobisvaleronitrile, and polymer azo polymerization initiators. These can be used alone or in combination. Moreover, in the said superposition | polymerization, in order to adjust the molecular weight of an acrylic resin, a conventionally well-known chain transfer agent can be used.

  The mass average molecular weight of the acrylic copolymer described above is preferably in the range of 100,000 to 2,000,000, more preferably in the range of 200,000 to 1,000,000. If the weight average molecular weight is less than 100,000, the pressure-sensitive adhesive composition may be inferior in tackiness. On the other hand, if the weight average molecular weight exceeds 2,000,000, the coating property of the pressure-sensitive adhesive composition may be deteriorated. In some cases, the compatibility with the thermosetting resin is lowered, making it difficult to obtain desired tackiness. The mass average molecular weight can be measured by GPC (gel permeation chromatography) using a polystyrene standard sample.

<Epoxy thermosetting resin>
The epoxy thermosetting resin used in the pressure-sensitive adhesive composition according to the present invention is a prepolymer having at least one epoxy group or glycidyl group, and can be cured by a crosslinking polymerization reaction in combination with a curing agent. If there is, it can be used without any particular limitation. By using such a thermosetting epoxy resin, the chemical resistance of the pressure-sensitive adhesive composition can be improved. As a result, even if chemical treatment is performed after bonding to the adherend, The occurrence of peeling can be suppressed. In addition, in this invention, an epoxy thermosetting resin means the precursor or composition before resin hardens | cures, and what was hardened by heating shall be called epoxy thermosetting resin. In the present invention, the epoxy equivalent is 100 to 2000 g / eq. It is preferable to use those within the range. Epoxy equivalent is 100 g / eq. If the epoxy thermosetting resin is less than 1, the cross-linking density becomes too high, and the tackiness may decrease from the desired range, while 2000 g / eq. In the case of an epoxy thermosetting resin exceeding 1, when the pressure-sensitive adhesive composition is cured to form a pressure-sensitive adhesive layer, the heat resistance of the pressure-sensitive adhesive layer may be insufficient. In addition, an epoxy equivalent is the gram number of resin containing the epoxy group of 1 gram equivalent measured by the method based on JISK7236.

  There is no restriction | limiting in particular in the mass average molecular weight of the epoxy thermosetting resin used in this invention, Although it can select suitably by the use of an adhesive sheet, from a compatible viewpoint with an acrylic resin, generally 300- Those within the range of 5000 can be suitably used. From the viewpoint of durability of the pressure-sensitive adhesive layer, it is more preferable to use a high molecular weight within the above range.

  Examples of such epoxy thermosetting resins include bisphenol type epoxy resins such as bisphenol A type epoxy resins and bisphenol F type epoxy resins, novolac type epoxy resins such as novolac epoxy resins and cresol novolac epoxy resins, biphenyl type epoxy resins, and stilbene. Type epoxy resin, triphenolmethane type epoxy resin, alkyl-modified triphenolmethane type epoxy resin, triazine nucleus-containing epoxy resin, dicyclopentadiene-modified phenol type epoxy resin, etc., phenol novolac resin, cresol novolak Resin, novolac phenol resin such as bisphenol A novolac resin, phenol resin such as resol phenol resin, tria such as urea (urea) resin, melamine resin Resin having a gin ring, unsaturated polyester resins, bismaleimide resins, polyurethane resins, diallyl phthalate resins, alkoxy group-containing silane-modified epoxy resins, resins having a benzoxazine ring, cyanate ester resins. Among these epoxy resins, in the present invention, an epoxy resin having a rigid structure such as a biphenyl skeleton, a bisphenol skeleton, or a stilbene skeleton in the main chain is preferable, more preferably a bisphenol type epoxy resin, and particularly preferably a bisphenol A type epoxy. Resin.

  The above-described bisphenol A type epoxy resin may be liquid at room temperature or solid at room temperature depending on the number of repeating units of the bisphenol skeleton. The bisphenol A type epoxy resin having 1 to 3 carbon atoms in the main chain is liquid at normal temperature, and the bisphenol A type epoxy resin having 2 to 10 carbon atoms in the main chain is solid at normal temperature. Such a relatively low molecular weight bisphenol A type epoxy resin has crystallinity, and even if it is a solid substance that is crystallized at room temperature, it rapidly melts and changes to a low viscosity liquid. . Such a relatively low molecular weight bisphenol A type epoxy resin is characterized by high curability and low hygroscopicity (because the free volume is small) because the crosslink density is high upon curing. As the bisphenol A type epoxy resin solid at room temperature, those having a glass transition temperature in the range of 50 to 150 ° C. are preferred from the viewpoint of mechanical strength and heat resistance. Specifically, as a bisphenol A type epoxy resin having a main chain of 1 to 3 which is liquid at normal temperature, JER828 manufactured by Japan Epoxy Resin Co., Ltd. is a bisphenol A type epoxy having a main chain of 2 to 10 which is solid at normal temperature. Examples of the resin include JER1001 manufactured by Japan Epoxy Resin Co., Ltd.

  In the present invention, the above-described epoxy thermosetting resin needs to be contained in the range of 20 to 60% by mass with respect to the acrylic resin. By setting the blending amount of the epoxy thermosetting resin within the above range, an adhesive composition having a low initial adhesive force and capable of maintaining the adhesive force even when placed in a high temperature environment, and having little adhesive residue. It can be a thing. When the amount of the epoxy thermosetting resin is less than 20% by mass, the initial adhesive force tends to increase, and when the adhesive is placed in a high temperature environment, the adhesive force tends to increase. On the other hand, when the epoxy thermosetting resin is added in an amount exceeding 60% by mass, the initial adhesive strength (tack) is lowered, and it may be difficult to bond the adhesive sheet to the adherend at room temperature. The content of the preferable epoxy thermosetting resin is in the range of 30 to 50% by mass with respect to the acrylic resin.

<Curing agent>
The epoxy thermosetting resin described above is cured by heating and the like, but in the present invention, a curing agent for promoting the curing reaction is included in the pressure-sensitive adhesive composition. In the present invention, as a curing agent that reacts with an epoxy resin in an equivalent amount, for example, an amine-based curing agent, an acid anhydride-based curing agent, and a phenol-based curing agent can be suitably used, and an epoxy resin is used alone. As a curing agent that can be cured (polymerized) with imidazole, for example, an imidazole curing agent or a cationic curing agent can be preferably used. In the present invention, it is preferable to use an imidazole curing agent or a cationic curing agent that can be expected from the skeleton of the epoxy resin and can cure the epoxy resin alone even if the addition amount is small.

  Examples of amine curing agents include aliphatic polyamines such as diethylenetriamine (DETA), triethylenetetramine (TETA), and metaxylylene diamine (MXDA), diaminodiphenylmethane (DDM), m-phenylenediamine (MPDA), and diaminodiphenylsulfone. In addition to aromatic polyamines such as (DDS), polyamine compounds containing organic acid dihydralazide and the like can be mentioned. Examples of the acid anhydride curing agent include alicyclic acid anhydrides (liquid acid anhydrides) such as hexahydrophthalic anhydride (HHPA) and methyltetrahydrophthalic anhydride (MTHPA), trimellitic anhydride (TMA), And aromatic acid anhydrides such as pyromellitic anhydride (PMDA) and benzophenone tetracarboxylic acid (BTDA). Examples of the phenolic curing agent include phenol novolac resin, bisphenol novolac resin, poly p-vinylphenol, and the like. The aforementioned curing agents may be used alone or in combination of two or more.

  Moreover, as an imidazole type hardening | curing agent, imidazole, 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-isopropylimidazole, 2-phenylimidazole, carboxylate of an imidazole compound, an epoxy compound And adducts. Examples of the cationic curing agent include sulfonic acid ester, imide sulfonate, dialkyl-4-hydroxysulfonium salt, arylsulfonic acid-p-nitrobenzyl ester, silanol-aluminum complex, aromatic iodonium salt, aromatic sulfonium salt, aromatic diazonium. And salts, aromatic phosphonium salts, triazine compounds, iron arene complexes, and the like. The aforementioned curing agents may be used alone or in combination of two or more.

  The blending amount of the above-mentioned crosslinking agent is not particularly limited, but if the blending amount with respect to the epoxy thermosetting resin is small, the epoxy composition is cured when the pressure-sensitive adhesive composition is cured to form the pressure-sensitive adhesive layer. Insufficient curing such as an increase in the curing time of the thermosetting resin tends to be difficult, and it tends to be difficult to obtain desired tackiness. On the other hand, when the compounding amount of the curing agent is excessive, the storage stability of the pressure-sensitive adhesive composition may be reduced, or the curing density of the epoxy thermosetting resin may become too high to obtain desired tackiness. For example, when using a curing agent capable of curing (polymerizing) an epoxy resin alone, the curing agent may be blended in the range of 1 to 20% by mass with respect to the epoxy thermosetting resin. In the case of using a curing agent that reacts with an equivalent amount, the curing agent may be blended so as to have a ratio of 0.7 to 1.2 with respect to the epoxy equivalent of the epoxy thermosetting resin.

  The pressure-sensitive adhesive composition according to the present invention may contain a crosslinking agent. By adding a crosslinking agent, stickiness can be improved while maintaining the adhesive strength. A conventionally well-known thing can be used as a crosslinking agent, For example, a polyfunctional epoxy compound and an isocyanate compound are mentioned.

  Polyfunctional epoxy compounds include sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, glycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether, neopentyl glycol diglycidyl ether, 1 , 6-hexanediol diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, polybutadiene diglycidyl ether, and the like.

  As the isocyanate compound, a polyisocyanate compound, a trimer of a polyisocyanate compound, a urethane prepolymer having an isocyanate group at a terminal obtained by reacting a polyisocyanate compound and a polyol compound, a trimer of the urethane prepolymer Etc. Examples of the polyisocyanate compound include 2,4-tolylene diisocyanate, 2,5-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, diphenylmethane-4,4′-diisocyanate, 3 -Methyldiphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, dicyclohexylmethane-2,4'-diisocyanate, lysine isocyanate and the like. These crosslinking agents may be used alone or in combination of two or more.

  Furthermore, the pressure-sensitive adhesive composition according to the present invention can be applied to, for example, processability, heat resistance, weather resistance, mechanical properties, dimensional stability, antioxidant properties, slipperiness, releasability, and flame retardancy as necessary. For the purpose of improving and improving antifungal properties, electrical properties, strength, etc., for example, lubricants, plasticizers, fillers, fillers, antistatic agents, antiblocking agents, crosslinking agents, light stabilizers, dyes In addition, a colorant such as a pigment, and the like may be added. Further, if necessary, a coupling agent such as silane, titanium, and aluminum can be further included.

  The pressure-sensitive adhesive composition according to the present invention can be prepared by mixing the above-described components and kneading and dispersing as necessary. The mixing or dispersing method is not particularly limited, and a usual kneading and dispersing machine such as a two-roll mill, a three-roll mill, a pebble mill, a tron mill, a Szegvari attritor, a high-speed impeller disperser, a high-speed stone mill, A high speed impact mill, a desper, a high speed mixer, a ribbon blender, a kneader, an intensive mixer, a tumbler, a blender, a desperser, a homogenizer, an ultrasonic disperser, and the like can be applied. In addition, in order to adjust the viscosity of the pressure-sensitive adhesive coating solution, a diluent solvent may be added to mix each component.

<Adhesive sheet>
The pressure-sensitive adhesive sheet according to the present invention comprises a base material and a pressure-sensitive adhesive layer provided on one surface side of the base material, and the pressure-sensitive adhesive layer is obtained by thermosetting the above-mentioned pressure-sensitive adhesive composition. It is what you use.

  As a base material, the thing of various forms, such as a film form, a sheet form, or a tape form, can be used according to a use application. The material for the substrate can be appropriately selected depending on the intended use, and is not particularly limited. For example, from the viewpoint of water resistance and heat resistance, low density polyethylene, linear low density polyethylene, high density polyethylene, ethylene-propylene copolymer, polypropylene, polybutene, polybutadiene, polymethylpentene, ethylene-vinyl acetate copolymer Polyolefin resins such as polyethylene terephthalate and polyethylene naphthalate, polyamide resins such as nylon 6,6 and nylon 1,12, polyimide, ethylene- (meth) acrylic acid copolymer, ethylene- (meth) acrylic Acrylic copolymer such as acid methyl copolymer, ethylene- (meth) ethyl acrylate copolymer, etc., polyvinyl chloride resin, vinyl chloride vinyl acetate copolymer, ethylene-vinyl chloride-vinyl acetate copolymer, polyurethane , Ionomer resin, fluorine-based Fat, polystyrene resin, cellulose resin, polycarbonate resin, polyimide resin, polyvinyl alcohol resin, polyphenylene sulfide resin, phenol resin and the like. Among these, the base material composed of polyimide resin, polyphenylene sulfide resin, polyester resin has heat resistance, strength and flexibility, dimensional stability, energy ray permeability, stiffness, extensibility, Since it is excellent in lamination suitability and chemical resistance, it is preferably used as a base material for temporarily fixing or protecting the electronic component in the manufacturing process of the electronic component. These resins can be made into various forms such as film, sheet, or tape by forming into a sheet or film by extrusion molding and processing into a predetermined shape. Alternatively, two or more kinds of resins may be used in combination. The sheet or film formed by extrusion molding may be uniaxially stretched or biaxially stretched from the viewpoint of mechanical strength, or may be a laminated structure of two or more layers by a technique such as coextrusion. .

  The thickness of the base material is not particularly limited, and when the adhesive sheet is used as a protective sheet for an electronic circuit board or the like, it may be a thickness required according to the application, for example, a thickness of 5 to 500 μm. Can be used.

  In order for the base material to improve the adhesiveness with the pressure-sensitive adhesive layer, a corona treatment or a primer treatment may be applied to the surface side of the base material on which the pressure-sensitive adhesive composition is applied.

  The pressure-sensitive adhesive sheet according to the present invention can be obtained by forming the pressure-sensitive adhesive layer by applying the above-mentioned pressure-sensitive adhesive composition to one side of the substrate and heating and curing the pressure-sensitive adhesive composition. . The method for applying the pressure-sensitive adhesive composition to the substrate is not particularly limited. For example, roll coating, reverse roll coating, transfer roll coating, gravure coating, gravure reverse coating, comma coating, rod coating, blade coating Bar coat, wire bar coat, die coat, lip coat, dip coat, etc. can be applied.

  After applying the pressure-sensitive adhesive composition, the pressure-sensitive adhesive composition is cured by heating to form a pressure-sensitive adhesive layer. The heating temperature at the time of curing is about 50 to 150 ° C, preferably 90 to 120 ° C. The heating time may be appropriately adjusted depending on the heating temperature, but when the heating temperature is 90 to 150 ° C., it is 1 to 240 minutes, preferably several minutes to 60 minutes. Moreover, when heating temperature is 50-90 degreeC, it is 1 day (24 hours)-7 days (168 hours), Preferably it is 2 days (48 hours)-5 days (120 hours). Thus, cohesive force improves by hardening an adhesive layer beforehand before using an adhesive sheet, and the heat resistance and chemical resistance of an adhesive sheet improve.

  Although the pressure-sensitive adhesive sheet according to the present invention can be produced as described above, a release sheet may be provided on the surface of the pressure-sensitive adhesive layer opposite to the base material side in consideration of its handleability. . When providing a release sheet, the adhesive composition is applied to one side of the substrate and dried, and the release sheet is applied to the surface of the adhesive composition (the side opposite to the side with the substrate). After being provided, the pressure-sensitive adhesive composition may be thermally cured to form a pressure-sensitive adhesive layer.

  As the release sheet, conventionally known ones such as a release film, a separate paper, a separate film, a separate paper, a release film, and a release paper can be suitably used. Moreover, you may use what formed the release layer in the single side | surface or both surfaces of base materials for release paper, such as quality paper, a coated paper, an impregnation paper, and a plastic film. The release layer is not particularly limited as long as it has a releasability, and examples thereof include silicone resins, organic resin-modified silicone resins, fluororesins, aminoalkyd resins, melamine resins, acrylic resins, and polyester resins. It is done. These resins can be used in any of emulsion type, solvent type and solventless type.

  The release sheet is formed by applying a coating liquid in which a release layer component is dispersed and / or dissolved to one side of a release paper base film, followed by heating and drying and / or curing. As a coating method of the coating liquid, a known and arbitrary coating method can be applied, for example, roll coating, gravure coating, spray coating and the like. Moreover, you may form a release layer in the whole surface or a part of at least single side | surface of a base film as needed.

  The pressure-sensitive adhesive sheet having a release sheet is attached by peeling the release sheet from the pressure-sensitive adhesive sheet and bonding the release surface of the pressure-sensitive adhesive sheet to the adherend before bonding the pressure-sensitive adhesive sheet to the adherend. An adhesive sheet can be applied to the surface of the body. Therefore, the pressure-sensitive adhesive sheet according to the present invention can be used as a masking sheet for an electronic circuit board, etc., and can be easily reapplied even if the circuit board is extremely thin. After joining, there is no floating or peeling, and even when placed in a high temperature environment, the adhesive strength does not change and it has excellent peelability, so circuit boards etc. due to adhesive residue etc. Contamination can also be reduced. Moreover, even if a chemical treatment or the like is performed after bonding to the adherend, the occurrence of floating or peeling can be suppressed.

  Examples The present invention will be described in more detail with reference to examples, but the present invention is not limited to the contents of these examples.

Example 1
<Preparation of pressure-sensitive adhesive composition>
Acrylic copolymer resin (mass average molecular weight of 20) containing, as monomer units, methyl acrylate, 2-ethylhexyl acrylate, acrylic acid, and 2-hydroxyethyl acrylate in a ratio of 50: 40: 0.5: 9.5, respectively. And a glass transition temperature of 6 ° C.). 100 parts by mass of this acrylic copolymer resin ethyl acetate solution (solid content 35% by mass) and liquid epoxy resin (bisphenol A type epoxy resin, epoxy equivalent: 190 g / eq., Molecular weight: 370, trade name: jER828) 14 parts by mass of Mitsubishi Chemical Corporation), 0.35 parts by mass of 2-ethyl-4-methylimidazole (trade name: Cyasol 2E4MZ, Shikoku Kasei Co., Ltd.) as a curing agent, and a mixed solvent of toluene and methyl ethyl ketone ( (Trade name: KT-11, mass ratio 1: 1, manufactured by DIC Graphics Co., Ltd.), stirred with a disper for 30 minutes at a rotation speed of 500 rpm, and then allowed to stand at room temperature until there are no air bubbles. Obtained.
Acrylic copolymer resin (mass average molecular weight of 20) containing, as monomer units, methyl acrylate, 2-ethylhexyl acrylate, acrylic acid, and 2-hydroxyethyl acrylate in a ratio of 50: 40: 0.5: 9.5, respectively. And a glass transition temperature of 6 ° C.). 100 parts by mass of this acrylic copolymer resin ethyl acetate solution (solid content 35% by mass) and a solid epoxy resin (bisphenol A type epoxy resin, epoxy equivalent: 480 g / eq., Molecular weight: 900, trade name: jER1001) 14 parts by mass of Mitsubishi Chemical Co., Ltd., 0.35 parts by mass of 2-methyl-4-ethylimidazole (trade name: Cyasol 2E4MZ, Shikoku Kasei Co., Ltd.) as a curing agent, and a mixed solvent of toluene and methyl ethyl ketone (Trade name: KT-11, mass ratio 1: 1, manufactured by DIC Graphics Co., Ltd.), stirred with a disper at a rotation speed of 500 rpm for 30 minutes, and then allowed to stand at room temperature until there are no air bubbles. Got.

<Production of adhesive sheet>
The obtained pressure-sensitive adhesive composition has an easy release treatment surface of a 38 μm-thick polyester film (trade name: SP-PET-01, manufactured by Mitsui Chemicals, Inc.) on which one side is subjected to an easy release treatment using a silicone release agent. After coating the entire surface using an applicator, it was dried in a drying oven at 110 ° C. for 1 minute to form an adhesive layer having a thickness of 10 μm. A pressure-sensitive adhesive sheet 1 was obtained by laminating a polyimide film substrate (trade name: Kapton 100H, manufactured by Toray DuPont) with a thickness of 25 μm on the surface of the formed pressure-sensitive adhesive layer and curing at 60 ° C. for 120 hours.

Example 2
A pressure-sensitive adhesive sheet 2 was obtained in the same manner as in Example 1 except that the blending amounts of the liquid epoxy resin and the curing agent were changed according to Table 1 below.

Example 3
Instead of the liquid epoxy resin used in Example 1, a solid epoxy resin (bisphenol A type epoxy resin, epoxy equivalent: 480 g / eq., Molecular weight: 900, trade name: jER1001, manufactured by Mitsubishi Chemical Corporation) was used, and an epoxy was used. Except having changed the compounding quantity of resin and a hardening | curing agent according to Table 1, it carried out similarly to Example 1, and obtained the adhesive sheet 3.

Example 4
A pressure-sensitive adhesive sheet 4 was obtained in the same manner as in Example 3 except that the blending amounts of the solid epoxy resin and the curing agent were changed according to Table 1 below.

Example 5
In place of the liquid epoxy resin used in Example 1, an alkoxy group-containing silane-modified epoxy resin (solid content 57% by mass, epoxy equivalent: 1420 g / eq., Molecular weight: 2400, trade name: Composelan E103D, manufactured by Arakawa Chemical Industries) Was used, and the pressure-sensitive adhesive sheet 5 was obtained in the same manner as in Example 1 except that the blending amounts of the epoxy resin and the curing agent were changed according to Table 1.

Example 6
Except having changed the compounding quantity of an epoxy resin and a hardening | curing agent according to following Table 1, it carried out similarly to Example 5, and obtained the adhesive sheet 6.

Example 7
In Example 4, Example 4 was added except that 0.2 parts by mass of an epoxy crosslinking agent (solid content: 50% by mass, trade name: E-5C, manufactured by Soken Chemical Co., Ltd.) was added as a crosslinking agent to the adhesive composition. In the same manner as above, an adhesive sheet 7 was obtained.

Example 8
In place of the polyimide film substrate having a thickness of 25 μm used in Example 4, a polyester film substrate having a thickness of 50 μm (trade name: A4100, manufactured by Toyobo Co., Ltd.) was used. Sheet 8 was obtained.

Example 9
A portion of the solid epoxy resin used in Example 8 was added to an alkoxy group-containing silane-modified epoxy resin (solid content 57% by mass, epoxy equivalent: 1420 g / eq., Molecular weight: 2400, trade name: Adhesive sticking in the same manner as in Example 8 except that the curing agent was changed to 1-benzyl-2-methylimidazole (trade name: Cyasol 1B2MZ, manufactured by Shikoku Kasei Co., Ltd.). Sheet 9 was obtained.

Example 10
A portion of the solid epoxy resin used in Example 8 was added to an alkoxy group-containing silane-modified epoxy resin (solid content 57% by mass, epoxy equivalent: 1420 g / eq., Molecular weight: 2400, trade name: Adhesive sticking in the same manner as in Example 8 except that the curing agent was changed to 1-benzyl-2-methylimidazole (trade name: Cyasol 1B2MZ, manufactured by Shikoku Kasei Co., Ltd.). Sheet 10 was obtained.

Example 11
A part of the solid epoxy resin used in Example 8 was a liquid epoxy resin (polycondensate of bisphenol A / epichlorohydrin / dimer acid, epoxy equivalent: 600 to 700 g / eq., Trade name: adhesive sheet 11 in the same manner as in Example 8 except that the curing agent was changed to 1-benzyl-2-methylimidazole (trade name: Cyasol 1B2MZ, manufactured by Shikoku Kasei Co., Ltd.). Got.

Comparative Example 1
A pressure-sensitive adhesive sheet 12 was obtained in the same manner as in Example 3 except that the blending amounts of the solid epoxy resin and the curing agent were changed according to Table 2 below.

Comparative Example 2
A pressure-sensitive adhesive sheet 13 was obtained in the same manner as in Example 3 except that the blending amounts of the solid epoxy resin and the curing agent were changed according to Table 2 below.

Comparative Example 3
A pressure-sensitive adhesive sheet 14 was obtained in the same manner as in Example 5 except that the blending amounts of the epoxy resin and the curing agent were changed according to Table 2 below.

Comparative Example 4
100 parts by mass of an acrylic pressure-sensitive adhesive (trade name: SK1439U, manufactured by Soken Chemical Co., Ltd.) and 0.6 mass of an epoxy crosslinking agent (solid content: 50% by mass, product name: E-5C, manufactured by Soken Chemical Co., Ltd.) as a curing agent Are dissolved in 151.5 parts by mass of a mixed solvent of toluene and methyl ethyl ketone (trade name: KT-11, mass ratio 1: 1, manufactured by DIC Graphics) and stirred with a disper at a rotation speed of 500 rpm for 30 minutes. The pressure-sensitive adhesive composition was obtained by allowing to stand until air bubbles disappeared at room temperature.

  The obtained pressure-sensitive adhesive composition has an easy release treatment surface of a 38 μm-thick polyester film (trade name: SP-PET-01, manufactured by Mitsui Chemicals, Inc.) on which one side is subjected to an easy release treatment using a silicone release agent. After coating the entire surface using an applicator, it was dried in a drying oven at 100 ° C. for 2 minutes to form an adhesive layer having a thickness of 10 μm. A pressure-sensitive adhesive sheet 15 was obtained by laminating a polyimide film substrate (trade name: Kapton 100H, manufactured by Toray DuPont) having a thickness of 25 μm on the surface of the formed pressure-sensitive adhesive layer.

Comparative Example 5
100 parts by mass of an acrylic pressure-sensitive adhesive (trade name: SK1439U, manufactured by Soken Chemical Co., Ltd.) and 0.6 mass of an epoxy crosslinking agent (solid content: 50% by mass, product name: E-5C, manufactured by Soken Chemical Co., Ltd.) as a curing agent And 6 parts by mass of a solid epoxy resin (bisphenol A type epoxy resin, trade name: jER1001, manufactured by Mitsubishi Chemical Corporation), a mixed solvent of toluene and methyl ethyl ketone (trade name: KT-11, mass ratio 1: 1) The product was dissolved in 157.5 parts by mass of DIC Graphics Co., Ltd., stirred with a disper at 500 rpm for 30 minutes, and then allowed to stand at room temperature until there were no air bubbles to obtain an adhesive composition. A pressure-sensitive adhesive sheet 16 was obtained in the same manner as in Comparative Example 4 using the obtained pressure-sensitive adhesive composition.

Comparative Example 6
<Preparation of pressure-sensitive adhesive composition>
100 parts by mass of a silicone adhesive having a solid content of 60% by mass (trade name: SD4600, manufactured by Toray Dow Corning) and two curing catalysts (trade names: SRX212 and BY24-741, both of which are Toray Dow Corning) 0.9 parts by mass and 1.5 parts by mass, respectively, dissolved in 100 parts by mass of a mixed solvent of toluene and methyl ethyl ketone (trade name: KT-11, mass ratio 1: 1, manufactured by DIC Graphics) The mixture was stirred with a disper at 500 rpm for 30 minutes, and then allowed to stand at room temperature until there were no bubbles, thereby obtaining a pressure-sensitive adhesive composition.

<Production of adhesive sheet>
The obtained pressure-sensitive adhesive composition was coated on the entire surface of a polyimide film substrate (trade name: Kapton 100H, manufactured by Toray DuPont) with a thickness of 25 μm using an applicator, and then dried at 100 ° C. in a drying oven. It was dried for 2 minutes to form an adhesive layer having a thickness of 10 μm. A pressure-sensitive adhesive sheet 17 was obtained by laminating a 40 μm-thick polypropylene film (trade name: Treffan BO-2500 # 40) on the surface of the formed pressure-sensitive adhesive layer.

Comparative Example 7
In place of the polyimide film substrate having a thickness of 25 μm used in Comparative Example 4, a polyester film substrate having a thickness of 50 μm (trade name: A4100, manufactured by Toyobo Co., Ltd.) was used. Sheet 18 was obtained.

<Evaluation of adhesive strength>
The obtained pressure-sensitive adhesive sheets 1 to 7 and 12 to 17 were cut into a size of 25 mm × 150 mm, the polyester film subjected to the easy peeling treatment was peeled from the pressure-sensitive adhesive sheet to expose the pressure-sensitive adhesive layer, and the pressure-sensitive adhesive of the pressure-sensitive adhesive sheet The layer is bonded to a copper foil (trade name: RCF-T58, manufactured by Fukuda Metal Foil Powder Industry Co., Ltd.) and pressure-bonded using a 2 kg roller, and at room temperature and normal pressure (about 23 ° C., about 60% RH). For 20 minutes, and using a tensile tester (model number: RTF-1150H, manufactured by A & D), measurement conditions in accordance with JIS Z 0237 (tensile speed: 300 mm / min, peel distance: 150 mm, peel (Angle: 180 degrees), the adhesive force when peeling the adhesive sheet from the copper foil was measured (initial adhesive force). Also, after the adhesive sheet and the copper foil are bonded and pressure-bonded using a 2 kg roller, the adhesive strength after being left in an environment at 230 ° C. for 60 minutes and then left in a room temperature and normal pressure environment for 60 minutes is also obtained. Measurement was performed in the same manner as described above (adhesive strength after heat treatment). Furthermore, instead of copper foil, a glass epoxy material having a thickness of 1.6 t (trade name: R1700 FR-4, manufactured by Panasonic Corporation) is used, and the initial adhesive strength and the adhesive strength after heat treatment are the same as described above. Was measured. The measurement results were as shown in Tables 1 and 2 below.

  It was visually observed whether or not the adhesive remained on the surface of the copper foil after the peel test was performed using a tensile tester. The case where the adhesive did not remain was marked with ◯, and the case where the adhesive remained was marked with x. The evaluation results were as shown in Tables 1 and 2 below.

  Further, the obtained pressure-sensitive adhesive sheets 8 to 11 and 18 were cut into a size of 25 mm × 150 mm, the polyester film subjected to the easy peeling treatment was peeled from the pressure-sensitive adhesive sheet to expose the pressure-sensitive adhesive layer, and the pressure-sensitive adhesive of the pressure-sensitive adhesive sheet The layer was bonded to a glass epoxy material having a thickness of 1.6 t (trade name: R1700 FR-4, manufactured by Panasonic Corporation), and pressure-bonded using a 2 kg roller, and normal temperature and normal pressure (about 23 ° C., about 60%). RH) After leaving in an environment for 20 minutes, the adhesive force when the adhesive sheet was peeled from the glass epoxy material was measured under the same measurement conditions as above (initial adhesive force). Moreover, after sticking an adhesive sheet and a glass epoxy material, and crimping | bonding using a 2 kg roller, after leaving to stand in 180 degreeC environment for 30 minutes, and then leaving to stand in normal temperature and normal pressure environment for 60 minutes Was also measured in the same manner as described above (adhesive strength after heat treatment). Furthermore, instead of the glass epoxy material, 0.7 t-thick glass (trade name: Eagle XG, manufactured by Corning) was used, and the initial adhesive strength and the adhesive strength after the heat treatment were measured under the same conditions as described above. . The measurement results were as shown in Tables 1 and 2 below.

  Moreover, also about the obtained adhesive sheets 8-11 and 18, it was observed visually whether the adhesive remained on the surface to the to-be-adhered body after performing a peeling test using a tensile tester. The case where the adhesive did not remain was marked with ◯, and the case where the adhesive remained was marked with x. The evaluation results were as shown in Tables 1 and 2 below.

<Evaluation of chemical resistance>
The obtained pressure-sensitive adhesive sheets 8 to 11 and 18 were cut into a size of 100 mm × 100 mm, the polyester film subjected to the easy peeling treatment was peeled off from the pressure-sensitive adhesive sheet to expose the pressure-sensitive adhesive layer, and a glass having a thickness of 0.7 t. (Product name: Eagle XG, manufactured by Corning). 2. In a 50 ° C. mixed acid (phosphoric acid 55%, acetic acid 30%, inorganic acid 5% or less, trade name: SEA-5, manufactured by Kanto Chemical Co., Inc.) so that the adhesive sheet / glass laminate is completely immersed. It was immersed for 5 minutes, washed with distilled water, and continuously immersed in a 4% sodium hydroxide aqueous solution at 50 ° C. for 2.5 minutes. Thereafter, it was washed with distilled water and dried at room temperature. Peeling of the pressure-sensitive adhesive sheet in the pressure-sensitive adhesive sheet / glass laminate after drying and penetration of the chemical solution from the edge of the pressure-sensitive adhesive sheet were confirmed with a microscope (model number: VHX600, manufactured by Keyence Corporation). The case where peeling was not recognized was evaluated as ◯, the case where peeling was observed as x, the case where the penetration of the chemical solution was less than 0.2 mm, and the case where the penetration of the chemical solution was 0.2 mm or more as x. . The evaluation results were as shown in Tables 1 and 2 below.

Claims (8)

An adhesive composition comprising an acrylic resin, an epoxy thermosetting resin, and a curing agent for curing the epoxy thermosetting resin,
The pressure-sensitive adhesive composition comprising 20 to 60% by mass of the epoxy thermosetting resin with respect to the acrylic resin.   The epoxy thermosetting resin has an epoxy equivalent of 100 to 2000 g / eq. The pressure-sensitive adhesive composition according to claim 1, wherein   The pressure-sensitive adhesive composition according to claim 1 or 2, wherein the epoxy thermosetting resin has a mass average molecular weight of 300 to 5,000.   The pressure-sensitive adhesive composition according to any one of claims 1 to 3, wherein the acrylic resin has a mass average molecular weight of 102 to 2,000,000. A pressure-sensitive adhesive sheet comprising a base material and a pressure-sensitive adhesive layer provided on one surface side of the base material,
The pressure-sensitive adhesive layer comprises an acrylic resin and an epoxy thermosetting resin;
The pressure-sensitive adhesive sheet comprising 20 to 60% by mass of the epoxy thermosetting resin with respect to the acrylic resin.   The pressure-sensitive adhesive sheet according to claim 5, comprising a release sheet on a surface opposite to the base material side of the pressure-sensitive adhesive layer. A method for producing a pressure-sensitive adhesive sheet comprising a base material and a pressure-sensitive adhesive layer provided on one surface side of the base material,
Apply the adhesive composition on one side of the substrate,
Forming a pressure-sensitive adhesive layer by heating and curing the pressure-sensitive adhesive composition;
Comprising
The pressure-sensitive adhesive composition comprises an acrylic resin, an epoxy thermosetting resin, and a curing agent for curing the epoxy thermosetting resin,
The epoxy thermosetting resin is contained in an amount of 20 to 60% by mass with respect to the acrylic resin. Apply and dry the pressure-sensitive adhesive composition on one side of the substrate,
A release sheet is provided on the surface of the pressure-sensitive adhesive composition to form a laminate,
The pressure-sensitive adhesive layer is formed by heating the laminate and curing the pressure-sensitive adhesive composition.
The method of claim 7 comprising: