JP2012007011A - Double-sided adhesive tape and method of joining with adherend using the same - Google Patents

Abstract

An object of the present invention is to provide a double-sided adhesive tape that is excellent in heat resistance, has little increase in adhesive force when peeled, and has no adhesive residue or contamination on an adherend.
A (meth) acrylic polymer is obtained by graft polymerization of a chain containing a cyclic ether group-containing monomer to 100 parts by weight, a tackifying resin having a softening point of 80 ° C. or higher, 5 to 100 parts by weight, and a photocation. A double-sided adhesive tape having an adhesive layer formed from an adhesive composition containing 0.2 to 10 parts by weight of a system polymerization initiator or a thermosetting catalyst is prepared.
[Selection figure] None

Description

  The present invention relates to a double-sided adhesive tape and a method of joining to an adherend using the same. More specifically, the present invention relates to a double-sided pressure-sensitive adhesive tape excellent in heat resistance without contamination of an adherend and a method for joining the same.

  Double-sided adhesive tape is generally used as a joining method for various materials, and may be used as an alternative to screwing or welding because of its ease of workability. In such applications, not only the adhesiveness is required, but when used in electrical appliances, electronic products, automobiles, etc., the ambient temperature becomes high and high heat resistance is required. Also, in the joining process of electronic components, solder reflow and various heat treatment processes may also pass, and high heat resistance that can cope with these processes has become necessary.

In response to such a demand, a heat-resistant adhesive (Patent Document 1) copolymerized with imide acrylate, a heat-resistant adhesive (Patent Document 2) that defines the shear storage modulus and the molecular weight of the polymer have been proposed, Furthermore, a heat-resistant pressure-sensitive adhesive (Patent Document 3) having a chain transfer substance and defining a gel fraction change before and after the solder reflow process is also disclosed.

JP 2002-285105 A JP 2004-196867 A JP 2007-302868 A

The present invention provides a double-sided adhesive tape excellent in heat resistance and having excellent adhesiveness and heat resistance that does not cause adhesive sticking due to sufficient retention and deformation even when used in applications requiring heat resistance. The purpose is to propose the joining method used.

  As a result of intensive studies to solve the above problems, the present inventors have found the following double-sided adhesive tape, and have completed the present invention.

  That is, the present invention relates to 100 parts by weight of a graft polymer obtained by graft-polymerizing a chain containing a cyclic ether group-containing monomer to a (meth) acrylic polymer, 5 to 100 parts by weight of a tackifying resin having a softening point of 80 ° C. or higher, and light. The present invention relates to a double-sided adhesive tape having an adhesive layer formed from an adhesive composition containing 0.2 to 10 parts by weight of a cationic polymerization initiator or a thermosetting catalyst.

The adhesive composition contains the cyclic ether group-containing monomer and other monomers, and the weight ratio of the cyclic ether group-containing monomer: other monomer is in the range of 90:10 to 10:90. possible.

  The said adhesive composition can contain a crosslinking agent further.

  The adhesive composition may further contain 5 to 100 parts by weight of an epoxy resin and / or an oxetane resin with respect to 100 parts by weight of the graft polymer.

  The cyclic ether group-containing monomer may be one or both of an epoxy group-containing monomer and an oxetane group-containing monomer.

The glass transition temperature of the (meth) acrylic polymer may be 250K or less.

  The said (meth) acrylic-type polymer can contain 0.2-10 weight% of hydroxyl-containing monomers as a monomer unit with respect to the said (meth) acrylic-type polymer whole quantity.

The graft polymer is composed of 2 to 50 parts by weight of the cyclic ether group-containing monomer and 5 to 50 parts by weight of other monomers to 100 parts by weight of the (meth) acrylic polymer, and 0.02 to 5 parts by weight of peroxide. It can be obtained by graft polymerization in the presence.

  The thermosetting catalyst may be at least one selected from the group consisting of an imidazole compound, an acid anhydride, a phenol resin, a Lewis acid complex, an amino resin, a polyamine, and a melamine resin.

  The photocationic polymerization initiator may be at least one selected from the group consisting of allylsulfonium hexafluorophosphate salt, sulfonium hexafluorophosphate salt, and bis (alkylphenyl) iodonium hexafluorophosphate. .

The present invention is also a method for bonding to an adherend using any one of the above double-sided adhesive tapes, wherein the adhesive composition contains a photocationic polymerization initiator, The present invention relates to a bonding method characterized in that the double-sided adhesive tape is irradiated with light and attached to an adherend within a predetermined time.

The present invention is also a method for bonding to an adherend using any one of the above double-sided adhesive tapes, wherein the adhesive composition contains a thermosetting catalyst, The present invention relates to a bonding method in which an adhesive tape and an adherend are attached and heat-treated.

  The double-sided adhesive tape of the present invention has a sufficient initial adhesive strength and is easily cured by light irradiation or heat treatment. The adhesive composition for forming the double-sided adhesive tape of the present invention has fluidity and is easy to handle in the production process of the graft polymer contained therein, resulting in processability and final adhesiveness. Is excellent.

The double-sided adhesive tape of the present invention is a tackifying resin having a softening point of 80 ° C. or more, 5 to 100, 100 parts by weight of a graft polymer obtained by graft polymerization of a chain containing a cyclic ether group-containing monomer to a (meth) acrylic polymer. It has a pressure-sensitive adhesive layer formed from a pressure-sensitive adhesive composition comprising 0.2 part by weight of a photocationic polymerization initiator or a thermosetting catalyst.

First, as the monomer unit contained in the (meth) acrylic polymer, any (meth) acrylate can be used and is not particularly limited. Here, preferably, for example, an alkyl (meth) acrylate having an alkyl group having 4 or more carbon atoms is contained in an amount of 50% by weight or more of the entire (meth) acrylic polymer.

  In the present specification, the term “alkyl (meth) acrylate” simply refers to a (meth) acrylate having a linear or branched alkyl group. The alkyl group has 4 or more carbon atoms, preferably 4 to 9 carbon atoms. (Meth) acrylate refers to acrylate and / or methacrylate, and (meth) of the present invention has the same meaning.

  Specific examples of the alkyl (meth) acrylate include n-butyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, isobutyl (meth) acrylate, n-pentyl (meth) acrylate, and isopentyl. (Meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, isoamyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, n-nonyl ( (Meth) acrylate, isononyl (meth) acrylate, n-decyl (meth) acrylate, isodecyl (meth) acrylate, n-dodecyl (meth) acrylate, isomyristyl (meth) acrylate, n-tridecyl (meth) acrylate Rate, n- tetradecyl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate. Especially, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, etc. can be illustrated and these can be used individually or in combination.

  In this invention, the said alkyl (meth) acrylate is 50 weight% or more with respect to all the monomer components of a (meth) acrylic-type polymer, Preferably it is 80 weight% or more, More preferably, it is 90 weight% or more. Further, all the monomers may be alkyl (meth) acrylates, but are preferably 99% by weight or less, and may be 98% by weight or less or 97% by weight or less.

  In addition to this, it is preferable that the (meth) acrylic polymer of the present invention contains a hydroxyl group-containing monomer containing at least one hydroxyl group in the alkyl group. That is, this monomer is a monomer containing one or more hydroxyalkyl groups. Here, the hydroxyl group is preferably present at the terminal of the alkyl group. Carbon number of an alkyl group becomes like this. Preferably it is 2-12, More preferably, it is 4-8, More preferably, it is 4-6. By including such a hydroxyl group-containing monomer, there is a positive effect on the position at which hydrogen abstraction occurs during graft polymerization and the compatibility between the graft polymer and the homopolymer of the cyclic ether group-containing monomer generated during graft polymerization. It is considered useful for preparing a graft polymer having good heat resistance.

As such a monomer, those having a polymerizable functional group having an unsaturated double bond of a (meth) acryloyl group and having a hydroxyl group can be used without particular limitation. For example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxy Hydroxyalkyl (meth) acrylates such as octyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, etc .; 4-hydroxymethylcyclohexyl (meth) acrylate, 4-hydroxybutyl vinyl ether Etc. Of these, hydroxyalkyl (meth) acrylate is preferably used.

The hydroxyl group-containing monomer is preferably 0.2% by weight or more, more preferably 0.5% by weight or more, and preferably 10% by weight or less based on the total amount of monomer components forming the (meth) acrylic polymer. More preferably, it is 3% by weight or less. Most preferably, it is 0.5 to 3% by weight.

  As the monomer component for forming the (meth) acrylic polymer, an unsaturated carboxylic acid-containing monomer can be used in addition to the monomer.

  As the unsaturated carboxylic acid-containing monomer, a monomer having a polymerizable functional group having an unsaturated double bond such as a (meth) acryloyl group or a vinyl group and having a carboxyl group can be used without particular limitation. Examples of the unsaturated carboxylic acid-containing monomer include (meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid. These can be used alone or in combination. Among these, it is preferable to use (meth) acrylic acid, particularly acrylic acid.

  The unsaturated carboxylic acid-containing monomer is preferably used in a proportion of 0.01 to 2% by weight, more preferably 0.05 to 2% by weight, based on the total amount of monomer components forming the (meth) acrylic polymer. %, More preferably 0.05 to 1.5% by weight, particularly preferably 0.1 to 1% by weight.

  As the monomer component for forming the (meth) acrylic polymer, other copolymerization monomers may be used alone or in combination as long as the object of the present invention is not impaired. Other comonomer includes, for example, a polymerizable functional group having an unsaturated double bond such as a (meth) acrylate having a C 4 alkyl group, a (meth) acryloyl group, or a vinyl group. And an aromatic ring-containing monomer having an aromatic ring. Specific examples of the (meth) acrylate having an alkyl group having less than 4 carbon atoms include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate and the like, and specific examples of the aromatic ring-containing monomer. Are phenoxyethyl (meth) acrylate, benzyl (meth) acrylate, phenol ethylene oxide modified (meth) acrylate, 2-naphthoethyl (meth) acrylate, 2- (4-methoxy-1-naphthoxy) ethyl (meth) acrylate, phenoxy Examples thereof include propyl (meth) acrylate, phenoxydiethylene glycol (meth) acrylate, and polystyryl (meth) acrylate.

  In addition, acid anhydride group-containing monomers such as maleic anhydride and itaconic anhydride; caprolactone adducts of acrylic acid; styrene sulfonic acid and allyl sulfonic acid, 2- (meth) acrylamide-2-methylpropane sulfonic acid, (meth) Sulfonic acid group-containing monomers such as acrylamide propanesulfonic acid, sulfopropyl (meth) acrylate, (meth) acryloyloxynaphthalene sulfonic acid; phosphoric acid group-containing monomers such as 2-hydroxyethyl acryloyl phosphate; methoxyethyl (meth) acrylate, ( And (meth) acrylic acid alkoxyalkyl monomers such as ethoxyethyl (meth) acrylate.

  In addition, vinyl monomers such as vinyl acetate, vinyl propionate, styrene, α-methylstyrene, N-vinylcaprolactam; glycidyl (meth) acrylate, methylglycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) Epoxy group-containing monomers such as acrylate; glycol-based acrylic ester monomers such as (meth) acrylic acid polyethylene glycol, (meth) acrylic acid polypropylene glycol, (meth) acrylic acid methoxyethylene glycol, (meth) acrylic acid methoxypolypropylene glycol; Acrylic ester monomers such as tetrahydrofurfuryl (meth) acrylate, fluorine (meth) acrylate, silicone (meth) acrylate and 2-methoxyethyl acrylate; Bromide group-containing monomers, amino group-containing monomers, imide group-containing monomer, N- acryloyl morpholine, may be used, such as vinyl ether monomers.

  The weight average molecular weight of the (meth) acrylic polymer of the present invention is preferably 600,000 or more, more preferably 700,000 to 3,000,000. The weight average molecular weight is a value measured by GPC (gel permeation chromatography) and calculated in terms of polystyrene.

Such a (meth) acrylic polymer can be produced by appropriately selecting a known production method such as solution polymerization, bulk polymerization, emulsion polymerization, and various radical polymerizations. Further, the (meth) acrylic polymer obtained may be either a random copolymer or a block copolymer.

  In solution polymerization, for example, ethyl acetate, toluene or the like is used as a polymerization solvent. As a specific example of solution polymerization, the reaction is performed under an inert gas stream such as nitrogen, and a polymerization initiator is added, and the reaction is usually performed at about 50 to 70 ° C. under reaction conditions of about 5 to 30 hours.

  The polymerization initiator, chain transfer agent, emulsifier and the like used for radical polymerization are not particularly limited and can be appropriately selected and used. In addition, the weight average molecular weight of a (meth) acrylic-type polymer can be controlled by the usage-amount of a polymerization initiator and a chain transfer agent, and reaction conditions, The usage-amount is suitably adjusted according to these kinds.

  Examples of the polymerization initiator include 2,2′-azobisisobutyronitrile, 2,2′-azobis (2-amidinopropane) dihydrochloride, 2,2′-azobis [2- (5-methyl-2). -Imidazolin-2-yl) propane] dihydrochloride, 2,2'-azobis (2-methylpropionamidine) disulfate, 2,2'-azobis (N, N'-dimethyleneisobutylamidine), 2,2 '-Azobis [N- (2-carboxyethyl) -2-methylpropionamidine] hydrate (manufactured by Wako Pure Chemical Industries, VA-057) and other azo initiators, and persulfates such as potassium persulfate and ammonium persulfate , Di (2-ethylhexyl) peroxydicarbonate, di (4-t-butylcyclohexyl) peroxydicarbonate, di-sec-butyl -Oxydicarbonate, t-butylperoxyneodecanoate, t-hexylperoxypivalate, t-butylperoxypivalate, dilauroyl peroxide, di-n-octanoyl peroxide, 1,1,3 , 3-tetramethylbutylperoxy-2-ethylhexanoate, di (4-methylbenzoyl) peroxide, dibenzoyl peroxide, t-butylperoxyisobutyrate, 1,1-di (t-hexylperoxy) ) Peroxides such as cyclohexane, t-butyl hydroperoxide, hydrogen peroxide, peroxides and sodium bisulfite, peroxides and sodium ascorbate Redox initiators combined with Not intended to be.

  The polymerization initiator may be used alone or in combination of two or more, but the total content is 0.005 to 1 part by weight with respect to 100 parts by weight of the monomer. Is preferably about 0.02 to 0.5 parts by weight.

  In order to produce the (meth) acrylic polymer having the weight average molecular weight using, for example, 2,2′-azobisisobutyronitrile as the polymerization initiator, the amount of the polymerization initiator used is a monomer. The total amount of the components is preferably about 0.06 to 0.3 parts by weight, more preferably about 0.08 to 0.2 parts by weight.

  Examples of the chain transfer agent include lauryl mercaptan, glycidyl mercaptan, mercaptoacetic acid, 2-mercaptoethanol, thioglycolic acid, 2-ethylhexyl thioglycolate, and 2,3-dimercapto-1-propanol. The chain transfer agent may be used alone or in combination of two or more, but the total content is 0.1 parts by weight with respect to 100 parts by weight of the total amount of monomer components. Less than or equal to

  Examples of the emulsifier used in emulsion polymerization include anionic emulsifiers such as sodium lauryl sulfate, ammonium lauryl sulfate, sodium dodecylbenzenesulfonate, ammonium polyoxyethylene alkyl ether sulfate, sodium polyoxyethylene alkyl phenyl ether sulfate, and polyoxy Nonionic emulsifiers such as ethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene fatty acid ester, and polyoxyethylene-polyoxypropylene block polymer are listed. These emulsifiers may be used alone or in combination of two or more.

  Further, as reactive emulsifiers, as emulsifiers into which radical polymerizable functional groups such as propenyl groups and allyl ether groups are introduced, specifically, for example, Aqualon HS-10, HS-20, KH-10, BC-05 BC-10, BC-20 (all of which are manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), Adeka Soap SE10N (manufactured by ADEKA), and the like. Reactive emulsifiers are preferable because they are incorporated into the polymer chain after polymerization and thus have improved water resistance. The amount of the emulsifier used is more preferably 0.3 to 5 parts by weight and 0.5 to 1 part by weight from the viewpoint of polymerization stability and mechanical stability with respect to 100 parts by weight of the total amount of monomer components.

The glass transition temperature (Tg) of the (meth) acrylic polymer is 250K or less, preferably 240K or less. The glass transition temperature is also preferably 200K or higher. When the glass transition temperature is 250 K or less, the adhesive composition has good heat resistance and excellent internal cohesive strength. Such a (meth) acrylic polymer can be adjusted by appropriately changing the monomer component and composition ratio to be used. Such glass transition temperature is, for example, by solution polymerization, using 0.06-0.2 parts by weight of a polymerization initiator such as azobisisovityronitrile or benzoyl peroxide, and using a polymerization solvent such as ethyl acetate. It is obtained by reacting at 50 ° C. to 70 ° C. for 8 to 30 hours under a nitrogen stream. Here, the glass transition temperature (Tg) is calculated from the following Fox equation.
1 / Tg = W1 / Tg1 + W2 / Tg2 + W3 / Tg3 +
The above-mentioned Tg1, Tg2, Tg3 and the like represent the glass transition temperatures of the individual copolymer components 1, 2, 3, etc. in absolute temperature, and W1, W2, W3 and the like represent the respective copolymer components. The weight fraction. In addition, the glass transition temperature (Tg) of the single polymer was obtained from Polymer Handbook (4th edition, John Wiley & Sons. Inc.).

  Next, a solution obtained by diluting the (meth) acrylic polymer thus obtained as it is or by adding a diluent is subjected to graft polymerization.

Although it does not specifically limit as a diluent, Ethyl acetate or toluene is illustrated.

Graft polymerization is carried out by reacting a (meth) acrylic polymer with a cyclic ether group-containing monomer and optionally a cyclic ether group-containing monomer and other monomers.

Here, the cyclic ether group-containing monomer is not particularly limited, but is preferably an epoxy group-containing monomer, an oxetane group-containing monomer, or a combination of both.

Examples of the epoxy group-containing monomer include glycidyl acrylate, glycidyl methacrylate, 3,4-epoxycyclohexylmethyl acrylate, 3,4-epoxycyclohexylmethyl methacrylate, or 4-hydroxybutyl acrylate glycidyl ether. These may be used alone or in combination. Can be used.

Examples of the oxetane group-containing monomer include 3-oxetanylmethyl (meth) acrylate, 3-methyl-3-oxetanylmethyl (meth) acrylate, 3-ethyl-3-oxetanylmethyl (meth) acrylate, and 3-butyl-3-oxetanylmethyl. (Meth) acrylate or 3-hexyl-3-oxetanylmethyl (meth) acrylate is exemplified, and these can be used alone or in combination.

The amount of the cyclic ether group-containing monomer is preferably 2 parts by weight or more, more preferably 3 parts by weight or more with respect to 100 parts by weight of the (meth) acrylic polymer. The upper limit is not particularly limited, but is preferably 100 parts by weight or less, more preferably 50 parts by weight or less, and even more preferably 30 parts by weight or less. When the amount of the cyclic ether group-containing monomer is 2 parts by weight or more, the function of the composition as a pressure-sensitive adhesive is sufficiently exhibited. On the other hand, when the amount is 100 parts by weight or more, tackiness is reduced and initial adhesion is difficult. There is.

  It is also possible to use other monomers that co-graft with the cyclic ether group-containing monomer during the graft polymerization. Such a monomer is not particularly limited as long as it does not contain a cyclic ether group, and examples thereof include alkyl (meth) acrylates having 1 to 9 carbon atoms. Specific examples of the alkyl (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl acrylate and the like. Moreover, alicyclic (meth) acrylates such as cyclohexyl (meth) acrylate and isobornyl (meth) acrylate can also be used. These can be used alone or in combination.

The use of other monomers that are co-grafted at the time of grafting can facilitate the curing of the adhesive. For example, in the case of photocuring, the amount of light irradiation can be reduced. The amount of curing catalyst can be reduced. This is presumably because the mobility of the graft chain is increased, or because the compatibility between the graft chain and the by-product ungrafted chain and the backbone polymer is improved.

Such other monomers are also preferably selected from the same monomers as the main chain (trunk), that is, the components of the (meth) acrylic polymer.

When the amount of the monomer other than the cyclic ether group-containing monomer is blended, the weight ratio of the cyclic ether group-containing monomer to the cyclic ether group-containing monomer: other monomer, preferably 90:10 to 10:90. More preferably, it is 80:20 to 20:80. If the content of other monomers is small, the effect of reducing the amount of photocuring or heat curing for curing may not be sufficient, and if it is large, the peel resistance after photocuring or heat curing may increase.

Graft polymerization conditions are not particularly limited, and can be carried out by methods known to those skilled in the art. In the polymerization, it is preferable to use a peroxide as a polymerization initiator.
The amount of such a polymerization initiator is 0.02 to 5 parts by weight with respect to 100 parts by weight of the (meth) acrylic polymer. When the amount of this polymerization initiator is small, it takes too much time for the graft polymerization reaction, and when it is large, many homopolymers of cyclic ether group-containing monomers are formed, which is not preferable.

For example, if the graft polymerization is solution polymerization, a cyclic ether group-containing monomer and a viscosity-adjustable solvent are added to the acrylic copolymer solution, followed by nitrogen substitution, and then a peroxide system such as dibenzoyl peroxide. Although it can carry out by adding 0.02-5 weight part of polymerization initiators, and heating at 50 to 80 degreeC for 4 to 15 hours, it is not limited to this.

The state of the obtained graft polymer (molecular weight, branch polymer branch size, etc.) can be appropriately selected depending on the reaction conditions.

  The adhesive composition for forming the double-sided adhesive tape of the present invention contains the graft polymer thus obtained and a thermosetting catalyst of a cyclic ether group or a photocationic polymerization initiator.

  As the cyclic ether group thermosetting catalyst, any cyclic ether group thermosetting catalyst known to those skilled in the art can be preferably used. More specifically, at least one selected from the group consisting of imidazole compounds, acid anhydrides, phenol resins, Lewis acid complexes, amino resins, polyamines, and melamine resins can be used. Among these, an imidazole compound is particularly preferable, and the imidazole compound is not limited, but 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4- Methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2- Undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl-2-phenylimidazoli Such Mutorimeriteito are exemplified. These compounds are selected in consideration of the curing start temperature and compatibility with the adhesive.

  For example, when the adhesive polymer is a water-dispersed emulsion, 1,2-dimethylimidazole is selected, and 1-cyanoethyl is selected for the purpose of preserving storage or for thermosetting at a relatively high temperature. If 2-undecylimidazole is selected and the purpose is to cure at relatively low temperatures, 2-phenylimidazole can be selected.

  Such a cyclic ether group thermosetting catalyst may be used alone or as a mixture of two or more, but the total content is 100 parts by weight of the graft polymer. And 0.2 to 10 parts by weight.

  As the photocationic polymerization initiator, any photocationic polymerization initiator known to those skilled in the art can be preferably used. More specifically, at least one selected from the group consisting of allylsulfonium hexafluorophosphate salt, sulfonium hexafluorophosphate salt, and bis (alkylphenyl) iodonium hexafluorophosphate can be used. .

  Such a cationic photopolymerization initiator may be used alone or in combination of two or more, but the total content is based on 100 parts by weight of the graft polymer. 0.2 to 10 parts by weight.

Furthermore, 5-100 weight part of tackifying resin with a softening point of 80 degreeC or more is contained in the adhesive composition which forms the double-sided adhesive tape of this invention. Here, as tackifying resins having a softening point of 80 ° C. or higher, rosin-based tackifying resins such as rosin ester, polymerized rosin, disproportionated rosin, modified rosin, hydrogenated rosin, pinene resin, aromatic modified terpene, phenol modified Terpene tackifier resins such as terpenes and hydrogenated terpenes, saturated or unsaturated hydrogen tackifier resins such as C5, C9, and C5 / C9 copolymers, styrene tackifier resins, coumarone resins, coumarone indene resins Various tackifying resins such as can be used.

Specifically, YS resin TO125 (softening point 125 ° C.), YS resin TR105 (softening point 105 ° C.), etc. as aromatic modified terpene resins, YS polystar U115 (softening point 115 ° C.), YS polyster 2130, etc. (Softening point 130 ° C), YS Polystar T145 (softening point 145 ° C), YS Polystar T130 (softening point 130 ° C), YS Polystar S145 (softening point 145 ° C), Mighty Ace G150 (softening point 150 ° C) (all Yashara Chemical) Can be used. Super ester A-125 (softening point 120 ° C) as rosin ester resin, Pencel D-135 (softening point 135 ° C) as polymerized rosin ester resin, Tamanol 135 (softening point 135 ° C) as rosin-modified phenolic resin, acid-modified rosin Pine crystal KE604 (softening point 125 ° C.), etc. (both manufactured by Arakawa Chemical Industries, Ltd.) can be used. As the styrene resin, YS Resin SX-85 (softening point: 85 ° C., manufactured by Yashara Chemical Co., Ltd.), Crystallex 3085 (softening point: 85 ° C., manufactured by Eastman Chemical), etc. can be used.

Two or more kinds of such tackifying resins may be used in combination, but the blending amount is 5 to 100 parts by weight, preferably 10 to 60 parts by weight, based on 100 parts by weight of the graft polymer. If the amount is too small, the effect of improving adhesiveness cannot be exhibited, and if the amount is too large, the tack is lowered, which is not preferable. Moreover, when it is necessary to adjust the refractive index of an adhesive, you may employ | adopt the tackifying resin which has aromatics, such as a styrene-type tackifying resin.

  A cross-linking agent is added to the adhesive composition that forms the double-sided adhesive tape of the present invention, if necessary. Although it does not specifically limit as a crosslinking agent, Isocyanate which is a compound which has two or more isocyanate groups (including the isocyanate reproduction | regeneration functional group which protected the isocyanate group temporarily by the blocking agent or quantification etc.) in 1 molecule. A system crosslinking agent is illustrated.

  Examples of the isocyanate-based crosslinking agent include aromatic isocyanates such as tolylene diisocyanate and xylene diisocyanate, alicyclic isocyanates such as isophorone diisocyanate, and aliphatic isocyanates such as hexamethylene diisocyanate.

  More specifically, for example, lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate, alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate and isophorone diisocyanate, 2,4-tolylene diisocyanate, Aromatic diisocyanates such as 4,4′-diphenylmethane diisocyanate, xylylene diisocyanate, polymethylene polyphenyl isocyanate, trimethylolpropane / tolylene diisocyanate trimer adduct (trade name Coronate L manufactured by Nippon Polyurethane Industry Co., Ltd.), tri Methylolpropane / hexamethylene diisocyanate trimer adduct (product name: Coronate HL, manufactured by Nippon Polyurethane Industry Co., Ltd.), hexamethylene diiso Isocyanurate of anate (product name: Coronate HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) And polyisocyanates polyfunctionalized with allophanate bonds. Of these, it is preferable to use an aliphatic isocyanate because of its high reaction rate.

The above isocyanate-based crosslinking agents may be used alone or as a mixture of two or more, but the total content is based on 100 parts by weight of the graft polymer. It is preferable to contain 0.01 to 2 parts by weight of the compound crosslinking agent, more preferably 0.02 to 2 parts by weight, and 0.05 to 1.5 parts by weight. Further preferred. It can be appropriately contained in consideration of cohesive force and prevention of peeling in a durability test.

Such an isocyanate-based crosslinking agent is preferably used because it can contribute to the curing reaction of the cyclic ether group in the graft chain together with the crosslinking of the main chain of the adhesive polymer.

  Moreover, you may use together an organic type crosslinking agent and a polyfunctional metal chelate as a crosslinking agent. Examples of the organic crosslinking agent include epoxy crosslinking agents (referring to compounds having two or more epoxy groups in one molecule). Examples of the epoxy-based crosslinking agent include ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, terephthalic acid diglycidyl ester acrylate, spiroglycol diglycidyl ether, and the like. These may be used alone or in combination of two or more.

  A polyfunctional metal chelate is one in which a polyvalent metal is covalently or coordinately bonded to an organic compound. Examples of polyvalent metal atoms include Al, Cr, Zr, Co, Cu, Fe, Ni, V, Zn, In, Ca, Mg, Mn, Y, Ce, Sr, Ba, Mo, La, Sn, Ti, and the like. can give. Examples of the atom in the organic compound that is covalently or coordinately bonded include an oxygen atom, and the organic compound includes an alkyl ester, an alcohol compound, a carboxylic acid compound, an ether compound, a ketone compound, and the like.

  In the present invention, it is also possible to add an oxazoline-based crosslinking agent or peroxide as a crosslinking agent.

  As the oxazoline-based crosslinking agent, those having an oxazoline group in the molecule can be used without particular limitation. The oxazoline group may be any of a 2-oxazoline group, a 3-oxazoline group, and a 4-oxazoline group. As the oxazoline-based cross-linking agent, a polymer obtained by copolymerizing an unsaturated monomer with an addition-polymerizable oxazoline is preferable, and a compound using 2-isopropenyl-2-oxazoline as the addition-polymerizable oxazoline is particularly preferable. As an example, trade name “Epocross WS-500” manufactured by Nippon Shokubai Co., Ltd. can be cited.

The peroxide can be used as appropriate as long as it generates radical active species by heating and proceeds with crosslinking of the base polymer of the adhesive composition, but in consideration of workability and stability, It is preferable to use a peroxide having a one-minute half-life temperature of 80 ° C. to 160 ° C., and more preferable to use a peroxide having a 90 ° C. to 140 ° C.

  Examples of peroxides that can be used include di (2-ethylhexyl) peroxydicarbonate (1 minute half-life temperature: 90.6 ° C.), di (4-t-butylcyclohexyl) peroxydicarbonate (1 Minute half-life temperature: 92.1 ° C.), di-sec-butyl peroxydicarbonate (1 minute half-life temperature: 92.4 ° C.), t-butyl peroxyneodecanoate (1 minute half-life temperature: 103 0.5 ° C), t-hexyl peroxypivalate (1 minute half-life temperature: 109.1 ° C), t-butyl peroxypivalate (1 minute half-life temperature: 110.3 ° C), dilauroyl peroxide ( 1 minute half-life temperature: 116.4 ° C.), di-n-octanoyl peroxide (1 minute half-life temperature: 117.4 ° C.), 1,1,3,3-tetramethylbutyl Oxy-2-ethylhexanoate (1 minute half-life temperature: 124.3 ° C), di (4-methylbenzoyl) peroxide (1 minute half-life temperature: 128.2 ° C), dibenzoyl peroxide (half-minute for 1 minute) Period temperature: 130.0 ° C.), t-butyl peroxyisobutyrate (1 minute half-life temperature: 136.1 ° C.), 1,1-di (t-hexylperoxy) cyclohexane (1 minute half-life temperature: 149.2 ° C.). Especially, since the crosslinking reaction efficiency is excellent, di (4-t-butylcyclohexyl) peroxydicarbonate (1 minute half-life temperature: 92.1 ° C.), dilauroyl peroxide (1 minute half-life temperature: 116. 4 ° C), dibenzoyl peroxide (1 minute half-life temperature: 130.0 ° C) and the like are preferably used.

  The peroxide half-life is an index representing the decomposition rate of the peroxide, and means the time until the remaining amount of peroxide is reduced to half. The decomposition temperature for obtaining a half-life at an arbitrary time and the half-life time at an arbitrary temperature are described in the manufacturer catalog, for example, “Organic peroxide catalog 9th edition by Nippon Oil & Fats Co., Ltd.” (May 2003) ".

  The peroxide may be used alone or as a mixture of two or more thereof, but the total content of the peroxide is 100 parts by weight of the graft polymer. 0.01 to 2 parts by weight, preferably 0.04 to 1.5 parts by weight, more preferably 0.05 to 1 part by weight. In order to adjust processability, reworkability, cross-linking stability, peelability, and the like, it is appropriately selected within this range.

  In addition, as a measuring method of the peroxide decomposition amount which remained after the reaction process, it can measure by HPLC (high performance liquid chromatography), for example.

More specifically, for example, after about 0.2 g of the adhesive composition after reaction treatment is taken out, immersed in 10 ml of ethyl acetate, and extracted by shaking at 25 ° C. and 120 rpm for 3 hours with a shaker. Let stand at room temperature for 3 days. Next, 10 ml of acetonitrile was added, shaken at 120 rpm at 25 ° C. for 30 minutes, and about 10 μl of the extract obtained by filtration through a membrane filter (0.45 μm) was injected into the HPLC for analysis. The amount of peroxide can be set.

  Although the adhesive layer is formed by the crosslinking agent, in the formation of the adhesive layer, the addition amount of the entire crosslinking agent is adjusted, and the influence of the crosslinking treatment temperature and the crosslinking treatment time is sufficiently considered. There is a need.

  The adhesive composition for forming the double-sided adhesive tape of the present invention may further contain an epoxy resin or an oxetane resin in order to further improve the adhesive strength and heat resistance.

Examples of the epoxy resin include bisphenol A type, bisphenol F type, bisphenol S type, brominated bisphenol A type, hydrogenated bisphenol A type, bisphenol AF type, biphenyl type, naphthalene type, fluorene type, phenol novolac type, cresol novolac type. Examples thereof include bifunctional epoxy resins such as trishydroxyphenylmethane type and tetraphenylolethane type and polyfunctional epoxy resins, and glycidylamine types such as hydantoin type and trisglycidyl isocyanurate type. These epoxy resins can be used alone or in combination of two or more.

  These epoxy resins are not limited, but commercially available epoxy resins can be used. Examples of such commercially available epoxy resins include, but are not limited to, for example, bisphenol type epoxy resins such as Japan Epoxy Resin Co., Ltd. jER828, jER806, etc .; alicyclic epoxy resins such as Japan Epoxy Resin Co., Ltd. YX8000, YX8034, etc. ADEKA Co., Ltd. EP4000, EP4005, etc .; polyglycidyl ethers of polyalcohols include known epoxy resins such as Nagase ChemteX Corporation Denacol EX-313, EX-512, EX-614B, EX-810, etc. .

Examples of the oxetane resin include xylylene oxetane such as 1,4-bis {[(3-ethyl-3-oxetanyl) methoxy] methyl} benzene, 3-ethyl-3-{[3-ethyloxetane-3-yl] methoxy. } Methyl} oxetane, 3-ethylhexyloxetane, 3-ethyl-3-hydroxyoxetane, 3-ethyl-3-hydroxymethyloxetane, and other known oxetane resins can be used. These oxetane resins can be used singly or in combination of two or more.

The oxetane resin is not limited, but a commercially available resin can be used. Examples of such commercially available oxetane resins include Aron Oxetane OXT-121, OXT221, OXT101, and OXT212 manufactured by Toa Gosei Co., Ltd., but are not limited thereto.

Such an epoxy resin and oxetane resin can be used for the adhesive composition which forms the double-sided adhesive tape of this invention combining either one or both.

In the present invention, when the epoxy resin and / or oxetane resin is contained with respect to 100 parts by weight of the graft polymer, the total amount thereof is preferably 5 parts by weight or more, more preferably 10 parts by weight or more, preferably Is 100 parts by weight or less, more preferably 70 parts by weight or less. When the total amount is 5 parts by weight or more, a remarkable effect is recognized in improving the adhesive strength and heat resistance. When the total amount exceeds 100 parts by weight, it may not be sufficiently cured.

In the present invention, when an epoxy resin is added to a graft polymer obtained by grafting a cyclic ether group-containing monomer to an acrylic polymer, a composition capable of producing a good adhesive layer in which no glue sticking out occurs before curing. Can be prepared. This is presumably because the grafted cyclic ether group is compatible with the low molecular weight epoxy resin to form a strong adhesive layer structure.

  In addition, a softener can be added to the adhesive composition for forming the double-sided adhesive tape of the present invention.

Furthermore, in order to increase the water resistance at the interface, a silane coupling agent is added to 100 parts by weight of the (meth) acrylic polymer in the adhesive composition forming the double-sided adhesive tape of the present invention. You may mix | blend 0.01-2 weight part. Preferably, 0.02 to 1 part by weight is blended. If it is this range, the adhesive force to a liquid crystal cell is moderate, it is excellent in removability, and durability is also hold | maintained.

Examples of the silane coupling agent include epoxy group-containing silane coupling agents such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 2- (3,4 epoxycyclohexyl) ethyltrimethoxysilane. Amino group-containing silane cups such as 3-aminopropyltrimethoxysilane, N-2 (aminoethyl) 3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl-N- (1,3-dimethyl-butylidene) propylamine Ring agents, (meth) acryl group-containing silane coupling agents such as 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, and isocyanate group-containing silane couplings such as 3-isocyanatopropyltriethoxysilane , And the like.

The adhesive composition for forming the double-sided adhesive tape of the present invention may contain other known additives, such as powders such as colorants and pigments, dyes, and surfactants. , Plasticizer, surface lubricant, leveling agent, softener, antioxidant, anti-aging agent, light stabilizer, ultraviolet absorber, polymerization inhibitor, inorganic or organic filler, metal powder, particulate, foil Or the like can be added as appropriate according to the use for which the material is used. Moreover, you may employ | adopt the redox system which added a reducing agent within the controllable range.

The adhesive layer contained in the double-sided adhesive tape of the present invention is formed by coating the adhesive composition on both surfaces of the film substrate, drying and removing the polymerization solvent, etc., and crosslinking treatment. be able to. Or the double-sided adhesive tape excellent in heat resistance can be formed also by providing the adhesive layer formed on the separator (release film) as it is without a base material.

Although it does not specifically limit as a film base material of this invention, A heat resistant thing is more preferable. Examples of the film substrate include films of polyethylene terephthalate film, polyimide, aramid, polyethylene naphthalate, polyphenylene sulfide and the like as the plastic film support. The thickness of such a film is preferably 5 to 100 μm. Moreover, although fiber-type supports, such as a nonwoven fabric, cloth, and felt, can also be used, a nonwoven fabric support is employed in terms of cost and workability, and the basis weight thereof is preferably 5 to 15 g / m ² . Nonwoven fabrics containing natural fibers such as Manila hemp are preferred in terms of heat resistance. Moreover, a foamed sheet or the like subjected to a cross-linking treatment can also be used.

The double-sided adhesive tape of the present invention includes all forms such as a sheet and a vertically long tape.

  More specifically, for example, the adhesive layer is formed by applying the adhesive composition to a release-treated separator or the like, drying and removing the polymerization solvent, etc., and then crosslinking the adhesive composition. A method of transferring to a heat-resistant film substrate after forming the layer, or applying the adhesive composition on the heat-resistant film substrate from the beginning, drying and removing the polymerization solvent, etc. This can be achieved by the forming method.

In applying the adhesive, one or more solvents other than the polymerization solvent may be added as appropriate.

A silicone release liner is preferably used as the release-treated separator. Examples of the constituent material of the release liner include polyethylene, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, ethylene / vinyl acetate copolymer film, polybutylene terephthalate film, polyurethane film, Examples thereof include plastic films such as polypropylene, polyethylene terephthalate, and polyester films, porous materials such as paper, cloth, and nonwoven fabric, nets, foam sheets, metal foils, and suitable thin leaves such as laminates thereof. A plastic film is preferably used from the viewpoint of excellent surface smoothness. Or suitable thin leaf bodies, such as a sheet | seat, a net | network, a foam, metal foil, and these laminated bodies, etc. are mention | raise | lifted.

On such a liner or on a heat resistant film substrate, in the step of applying the adhesive composition for forming the double-sided adhesive tape of the present invention and drying to form an adhesive layer, As a method of drying the adhesive, an appropriate method can be appropriately employed depending on the purpose. Preferably, a method of heating and drying the coating film is used. The heat drying temperature is preferably 40 ° C to 200 ° C, more preferably 50 ° C to 180 ° C, and particularly preferably 70 ° C to 170 ° C. By setting the heating temperature within the above range, an adhesive having excellent adhesive properties can be obtained.

As the drying time, an appropriate time can be adopted as appropriate. The drying time is preferably 5 seconds to 20 minutes, more preferably 5 seconds to 10 minutes, and particularly preferably 10 seconds to 5 minutes.

  Moreover, an adhesive layer can be formed after forming an anchor layer on the surface of a film base material, or giving various easy-adhesion processes, such as a corona treatment and a plasma treatment. Moreover, you may perform an easily bonding process on the surface of an adhesive agent layer.

  Various methods are used as a method for forming the adhesive layer. Specifically, for example, roll coat, kiss roll coat, gravure coat, reverse coat, roll brush, spray coat, dip roll coat, bar coat, knife coat, air knife coat, curtain coat, lip coat, die coater, etc. Examples thereof include an extrusion coating method.

  The thickness of the adhesive layer is not particularly limited and is, for example, about 5 to 200 μm. Preferably, it is 10-100 micrometers, More preferably, it is 15-70 micrometers.

  When the adhesive layer is exposed, the adhesive layer may be protected with a sheet (separator) that has been subjected to a release treatment until practical use.

  Examples of the constituent material of the protective separator include plastic films such as polyethylene, polypropylene, polyethylene terephthalate, and polyester films, porous materials such as paper, cloth, and nonwoven fabric, nets, foam sheets, metal foils, and the like. Although an appropriate thin leaf body such as a laminate can be mentioned, a plastic film is preferably used from the viewpoint of excellent surface smoothness.

  The plastic film is not particularly limited as long as it can protect the adhesive layer, for example, polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, chloride film. Examples thereof include a vinyl copolymer film, a polyethylene terephthalate film, a polybutylene terephthalate film, a polyurethane film, and an ethylene-vinyl acetate copolymer film.

  The thickness of the release liner for coating or protection and the separator is usually 5 to 200 μm, preferably about 5 to 100 μm. For the separator, if necessary, mold release and antifouling treatment with a silicone type, fluorine type, long chain alkyl type or fatty acid amide type release agent, silica powder, etc., coating type, kneading type, vapor deposition type It is also possible to carry out antistatic treatment such as. In particular, when the surface of the separator is appropriately subjected to a release treatment such as silicone treatment, long-chain alkyl treatment, or fluorine treatment, the peelability from the adhesive layer can be further enhanced.

When the adhesive composition used for the double-sided adhesive tape of the present invention contains a thermosetting catalyst, curing occurs by heating. Therefore, the double-sided adhesive tape of the present invention can be easily cured by heating after bonding to the adherend. By such a curing reaction, adhesion to the adherend or adhesion between the adherend and the member is ensured.

  Conditions such as the temperature of thermosetting are not particularly limited, but are preferably up to about 170 ° C. in consideration of the heat resistance of the support.

  By using a cyclic ether group thermosetting catalyst having a low curing start temperature, a curing reaction of the cyclic ether group occurs in the heat drying step together with the drying of the solvent and the reaction of the main chain polymer of the adhesive composition. A double-sided adhesive tape having an adhesive layer that is not completely thermoset is preferred.

  By using a cyclic ether group thermosetting catalyst having a high curing start temperature, only the drying of the solvent and the reaction of the main chain polymer of the adhesive composition proceed in this drying step, and the cyclic ether group remains. .

If the pressure-sensitive adhesive sheet in which the cyclic ether group remains is heated after adhesion to the adherend, and the curing reaction of the remaining cyclic ether group proceeds, both functions of temporary adhesion to the adherend and strong adhesion by heating Can also be expressed.

  Further, in the adhesive layer formed as described above, when the adhesive composition contains a photocationic polymerization initiator, curing occurs by irradiating specific light, and the present invention. A double-sided adhesive tape is prepared.

  Further, in the adhesive layer of the double-sided adhesive tape of the present invention, when the adhesive composition contains a photocationic polymerization initiator, photocuring occurs by irradiating with specific light. Bonding with the adherend becomes possible by adhering to the adherend within a predetermined time.

Although the light for irradiation is not specifically limited, Preferably, it is active energy rays, such as an ultraviolet-ray, visible light, and an electron beam. The crosslinking treatment by ultraviolet irradiation can be performed using an appropriate ultraviolet source such as a high-pressure mercury lamp, a low-pressure mercury lamp, an excimer laser, or a metal halide lamp. In this case, the irradiation amount of the ultraviolet ray can be appropriately selected according to the required degree of crosslinking, but it is usually preferable to select the ultraviolet ray within the range of 0.2 to 10 J / cm ^2. . Although the temperature at the time of irradiation is not specifically limited, Considering the heat resistance of a support body, about 140 degreeC is preferable.

The gel fraction of the adhesive layer of the double-sided adhesive tape of the present invention is 30 to 60%. Furthermore, when the curing reaction of the cyclic ether group is completed, the gel fraction becomes 60 to 90%, and the adhesive becomes very excellent in heat resistance.

Here, “after the thermosetting reaction” means a state that can be achieved by performing a heat treatment at least 150 ° C. for 60 minutes including a drying step. “After photocuring reaction” means, for example, a state in which ultraviolet rays of 0.2 J / cm ² or more are irradiated.

The double-sided adhesive tape of the present invention can take the following method as the adherend bonding method in the present invention due to the difference in curing reaction.
(1) After the curing reaction of the cyclic ether group of the double-sided adhesive tape of the present invention is completed (gel fraction is 60 to 90%), the double-sided adhesives obtained by curing the adherends to be joined together. Bonding with adherend tape can complete the joining of adherends. In this case, although the adhesive force itself is slightly lower than other methods, it is possible to achieve bonding with good heat resistance.
(2) The double-sided adhesive tape of the present invention in which a cyclic ether group remains using a thermosetting catalyst of a cyclic ether group (the gel fraction of the adhesive layer is preferably 30 to 60%). After attaching the adherends to each other with a double-sided adhesive tape, the cured cyclic ether groups can be cured by heating to adhere the adherends firmly and exhibit heat resistance. it can.
(3) Regarding the method of joining the double-sided adhesive tape of the present invention using a photocationic initiator to various adherends, if at least one adherend transmits ultraviolet rays, the adherends to be joined together. Are bonded with the double-sided adhesive tape of the present invention, and then irradiated with ultraviolet rays to carry out a curing reaction of the cyclic ether group, so that the adherends can be fixed more firmly.
(4) When both adherends do not transmit ultraviolet light to the double-sided adhesive tape of the present invention using a photocationic initiator, the double-sided adhesive tape of the present invention is applied to one of the adherends to be joined. After attaching and irradiating ultraviolet rays from the surface, the other adherend is attached while the pot life is long, so that the curing reaction of the cyclic ether group is performed, and the adherends are more firmly bonded to each other. Can be fixed. Irradiation with ultraviolet rays decomposes the photocation initiator, generates an acid, and proceeds with a curing reaction with a cyclic ether group. Various adherends can be bonded within 30 minutes after irradiation with active energy rays. Moreover, it is because a curing reaction can be advanced by irradiating an active energy ray after bonding to an adherend.

  In this method, even when the adherend transmits ultraviolet rays, one adherend is finely processed and bonded so that the adhesive does not flow and fill the finely processed portion. In this case, the double-sided adhesive tape of the present invention can be used. By irradiating the double-sided adhesive tape of the present invention with ultraviolet rays and initiating the curing reaction of the cyclic ether group, the surface that has been finely processed within the pot life is pasted, so that it is a normal pressure-sensitive adhesive even in subsequent storage It is possible to exhibit the feature that the penetration of the adhesive into the fine part seen in is not observed. Specifically, only the convex portions of the prism sheet or microlens film can be bonded, and the joining method does not impair the function of the prism or microlens.

  The double-sided adhesive tape of the present invention provides a double-sided adhesive tape having excellent heat resistance that can be used for fixing electronic components and electrical components inside automobiles, and is also adhesive in high-temperature atmospheres. The present invention also provides a bonding method using a double-sided adhesive tape having the characteristics that the adhesive agent has little decrease in adhesive property, the flowability of the pressure-sensitive adhesive polymer is very small and the retention property at high temperature is excellent.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In addition, all the parts and% in each example are based on weight. Unless otherwise specified, the room temperature standing conditions are all 23 ° C. and 65% RH (1 hour or 1 week).

(Regarding Examples 1-3 and Comparative Examples 1 and 2)
<Measurement of weight average molecular weight>
The weight average molecular weight of the obtained (meth) acrylic polymer was measured by GPC (gel permeation chromatography). The sample was prepared by dissolving the sample in dimethylformamide to give a 0.1% by weight solution, which was allowed to stand overnight and then filtered through a 0.45 μm membrane filter.
・ Analyzer: HLC-8120GPC manufactured by Tosoh Corporation
Column: manufactured by Tosoh Corporation, G7000H _XL + GMH _XL + GMH _XL
・ Column size: 7.8mmφ × 30cm each 90cm in total
・ Eluent: Tetrahydrofuran (concentration 0.1% by weight)
・ Flow rate: 0.8ml / min
・ Detector: Differential refractometer (RI)
-Column temperature: 40 ° C
・ Injection volume: 100 μl
・ Standard sample: Polystyrene

<Measurement of gel fraction>
The dried and crosslinked adhesive (initial weight W1) was immersed in an ethyl acetate solution and allowed to stand at room temperature for 1 week, then the insoluble matter was taken out and the dried weight (W2) was measured. I asked for it.
Gel fraction = (W2 / W1) × 100

<Measuring method of dynamic viscoelasticity>
Apparatus: ARES manufactured by TA Instruments
Deformation mode: Torsion measurement frequency: 1Hz constant frequency
Temperature increase rate: 5 ° C / min Measurement temperature: Measured from near the glass transition temperature of the adhesive to 160 ° C Shape: Parallel plate 8.0mmφ
Sample thickness: 0.5-2mm (initial stage)
Reading storage elastic modulus (G ') at 23 ° C

<Adhesive strength>
The double-sided adhesive tapes obtained in Examples 1 to 3 and Comparative Examples 1 and 2 are lined with a 38 μm polyethylene terephthalate film, cut to a width of 20 mm and a length of 100 mm, and a 2 Kg roll reciprocating on a float glass plate. Adhesion, treatment for 30 minutes in an autoclave at 50 ° C and 0.5Mpa, and then left for 3 hours under conditions of 23 ° C * 50% RH, then peel adhesion at a peel angle of 90 ° and a peel speed of 300mm / min (N / 20mm) The value obtained by measuring was defined as the initial adhesive strength.
The pasted sample was irradiated with UV rays at 3 J / cm ² and after-curing at 60 ° C. for 6 hours, then left at 23 ° C. * 50% RH for 3 hours, at a peeling angle of 90 ° and a peeling speed of 300 mm / min. The value obtained by measuring the peel adhesive strength (N / 20 mm) was defined as the adhesive strength after UV irradiation. In addition, in the sample of Example 3, UV irradiation (3 J / cm < ² >) was affixed on the glass plate immediately before affixing on a glass plate.

<Heat resistance>
The double-sided adhesive tapes obtained in Examples 1 to 3 and Comparative Examples 1 and 2 are lined with a 38 μm polyethylene terephthalate film, cut to a width of 10 mm and a length of 100 mm, and an adhesive area of 10 mm × 20 mm to a phenolic resin plate. Adhesive with and leave at 60 ° C for 24 hours, then drop the phenolic resin plate, apply a uniform load of 500 g to the free end of the adhesive tape, and the time (minutes) until the adhesive tape drops at 120 ° C. The measured value was defined as initial heat resistance. The pasted sample was irradiated with ultraviolet rays at 3 J / cm ² and aftercured at 60 ° C. for 6 hours, and then the phenolic resin plate was dropped and a uniform load of 500 g was applied to the free end of the adhesive tape at 120 ° C. The value obtained by measuring the time (minutes) until the adhesive tape drops was regarded as the heat resistance after UV irradiation. In addition, in the sample of Example 3, it was UV-irradiated (3 J / cm < ² >) before affixing on a phenol resin board, and affixed on the phenol resin board immediately.

Example 1
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser, 97 parts by weight of n-butyl acrylate, 3 parts by weight of 4-hydroxybutyl acrylate, and 2,2′-azobis as a polymerization initiator After charging 0.1 parts by weight of isobutyronitrile with 150 parts by weight of ethyl acetate, introducing nitrogen gas with gentle stirring and replacing with nitrogen for 1 hour, the liquid temperature in the flask was kept at around 60 ° C. for 10 hours. A polymerization reaction was performed to prepare an acrylic polymer solution having a weight average molecular weight of 1.6 million. The glass transition temperature of the obtained acrylic polymer was 225K.

The obtained acrylic polymer solution was diluted with ethyl acetate so that the solid content was 25% to prepare a diluted solution (I). In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser, 20 parts by weight of 4-hydroxybutyl acrylate glycidyl ether and 20 parts by weight of isobornyl acrylate with respect to 400 parts by weight of the diluted solution (I) And 0.2 parts by weight of benzoyl peroxide were added, nitrogen gas was introduced with gentle stirring, and the atmosphere was purged with nitrogen for 1 hour. Then, the liquid temperature in the flask was kept at around 65 ° C. for 4 hours, and then at 70 ° C. A polymerization reaction was carried out for 4 hours to obtain a graft polymer solution.

Next, 20 parts of YS Polystar S-145 (softening point 145 ° C., manufactured by Rashala Chemical Co., Ltd.) as tackifier resin with respect to 100 parts by weight of the solid content of the graft polymer solution thus obtained, allyl A pressure-sensitive adhesive solution was prepared by blending 1 part by weight of sulfonium hexafluorophosphate (manufactured by LAMBERTI, ESACURE 1064) and 0.2 part by weight of an adduct of trimethylolpropane with mexamethylene diisocyanate (Coronate HL, manufactured by Nippon Polyurethane).

  The adhesive solution was applied to a 38 μm polyethylene terephthalate film (MRF-38, manufactured by Mitsubishi Resin Co., Ltd.) subjected to silicone release treatment so that the thickness of the pressure-sensitive adhesive layer after drying was 40 μm. Dry for 3 minutes. Using a 25 μm polyethylene terephthalate film (manufactured by Toray, S-10) as a support, the above-mentioned pressure-sensitive adhesive layer was transferred to both sides to obtain a double-sided adhesive tape of the present invention.

(Example 2)
Other than using 20 parts by weight of Pencel D-125 (softening point 125 ° C., manufactured by Arakawa Chemical Co., Ltd.) as a tackifying resin with respect to 100 parts by weight of the solid content of the graft polymer solution obtained in Example 1. Performed the operation similar to Example 1, and obtained the double-sided adhesive tape of this invention.

Example 3
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube and a condenser, 82 parts by weight of n-butyl acrylate, 15 parts by weight of methyl acrylate, 3 parts by weight of 4-hydroxybutyl acrylate, 2 as a polymerization initiator , 2'-azobisisobutyronitrile with 0.1 parts by weight of ethyl acetate and 200 parts by weight of ethyl acetate were charged, nitrogen gas was introduced with gentle stirring, and the atmosphere was purged with nitrogen for 1 hour. A polymerization reaction was carried out for 10 hours while maintaining the vicinity to prepare an acrylic polymer solution having a weight average molecular weight of 1,200,000. The glass transition temperature of the obtained acrylic polymer was 234K.

The obtained acrylic polymer solution was diluted with ethyl acetate so that the solid content was 25% to prepare a diluted solution (I). In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser, 20 parts by weight of 4-hydroxybutyl acrylate glycidyl ether and 20 parts by weight of isobornyl acrylate with respect to 400 parts by weight of the diluted solution (I) And 0.12 parts by weight of benzoyl peroxide were added, nitrogen gas was introduced with gentle stirring, and the atmosphere was purged with nitrogen for 1 hour. The liquid temperature in the flask was kept at around 65 ° C. for 4 hours, and then at 70 ° C. A polymerization reaction was carried out for 4 hours to obtain a graft polymer solution.

  Next, 20 parts of YS Polystar S-145 (softening point 145 ° C., manufactured by Rashala Chemical Co., Ltd.) as tackifier resin with respect to 100 parts by weight of the solid content of the graft polymer solution thus obtained, allyl An adhesive solution was prepared by blending 1 part of sulfonium hexafluorophosphate (manufactured by LAMBERTI, ESACURE 1064) and 0.2 part of mexamethylene diisocyanate adduct of trimethylolpropane (Coronate HL, manufactured by Nippon Polyurethane).

  The adhesive solution was applied to a 38 μm polyethylene terephthalate film (MRF-38, manufactured by Mitsubishi Resin Co., Ltd.) subjected to silicone release treatment so that the thickness of the pressure-sensitive adhesive layer after drying was 40 μm. Dry for 3 minutes. Using a 25 μm polyethylene terephthalate film (manufactured by Toray, S-10) as a support, the above-mentioned pressure-sensitive adhesive layer was transferred to both sides to obtain a double-sided adhesive tape of the present invention.

(Comparative Example 1)
In Example 1, a crosslinking agent and a photocation initiator were blended in an acrylic polymer solution having a weight average molecular weight of 1.6 million consisting of 97 parts by weight of n-butyl acrylate and 3 parts by weight of 4-hydroxybutyl acrylate without graft polymerization. Then, the same operation as in Example 1 was performed to obtain a double-sided adhesive tape of Comparative Example 1.

(Comparative Example 2)
In Example 1, a cross-linking agent was added to the graft polymer without adding a photocation initiator, and the same operation as in Example 1 was performed to obtain a double-sided adhesive tape of Comparative Example 2.

Table 1 shows the evaluation results of the gel fraction, shear adhesive strength and heat resistance of the pressure-sensitive adhesive layer obtained for the samples obtained in the above Examples and Comparative Examples.

(Regarding Examples 4-6 and Comparative Examples 3-4)
<Gel fraction measurement method>
After drying and aging the pressure-sensitive adhesive layers of Examples 4 to 6 and Comparative Examples 3 and 4, the pressure-sensitive adhesive (initial weight W1) heated at 150 ° C. for 1 hour was immersed in an ethyl acetate solution at room temperature. After standing for 1 week, the insoluble matter was taken out and the dried weight (W2) was measured and determined as follows.
Gel fraction (%) = (W2 / W1) × 100

<Measuring method of dynamic viscoelasticity>
The dynamic viscoelasticity of the pressure-sensitive adhesive heat-treated at 150 ° C. for 1 hour was measured.
Apparatus: ARES manufactured by TA Instruments
Deformation mode: Torsion measurement frequency: 1Hz constant frequency
Temperature increase rate: 5 ° C / min Measurement temperature: Measured from near the glass transition temperature of the adhesive to 160 ° C Shape: Parallel plate 8.0mmφ
Sample thickness: 0.5-2mm (initial stage)
Reading storage elastic modulus (G ') at 23 ° C

<Adhesive strength>
The double-sided adhesive tapes obtained in Examples 4 to 6 and Comparative Examples 3 and 4 were lined with a 38 μm polyethylene terephthalate film, cut into a width of 20 mm and a length of 100 mm, and a 2 Kg roll reciprocating on a float glass plate. Adhesion, treatment for 30 minutes in an autoclave at 50 ° C and 0.5Mpa, and then left for 3 hours under conditions of 23 ° C * 50% RH, then peel adhesion at a peel angle of 90 ° and a peel speed of 300mm / min (N / 20mm) The value obtained by measuring was defined as the initial adhesive strength.

  The pasted sample was heat-treated at 150 ° C for 1 hour, then left at 23 ° C * 50% RH for 3 hours, and then peeled off at 90 ° and peeled off at 300mm / min. The measured value was defined as the adhesive strength after heat treatment.

<Heat resistance>
The double-sided adhesive tapes obtained in Examples 4 to 6 and Comparative Examples 3 and 4 are lined with a 38 μm polyethylene terephthalate film, cut to a width of 10 mm and a length of 100 mm, and bonded to a phenolic resin plate by 10 mm × 20 mm. Adhesive with and leave at 60 ° C for 24 hours, then drop the phenolic resin plate, apply a uniform load of 500 g to the free end of the adhesive tape, and the time (minutes) until the adhesive tape drops at 120 ° C. The measured value was defined as initial heat resistance.
The pasted sample was heat-treated at 150 ° C. for 1 hour, then the phenol resin plate was dropped and a uniform load of 500 g was applied to the free end of the adhesive tape, and the time (minutes) until the adhesive tape dropped at 120 ° C. ) Was measured as the heat resistance after the heat treatment.

Example 4
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser, 98 parts by weight of n-butyl acrylate, 2 parts by weight of 4-hydroxybutyl acrylate, and 2,2′-azobis as a polymerization initiator After charging 0.1 part by weight of isobutyronitrile with 200 parts by weight of ethyl acetate, introducing nitrogen gas with gentle stirring and replacing with nitrogen for 1 hour, the liquid temperature in the flask was kept at around 65 ° C. for 10 hours. A polymerization reaction was performed to prepare an acrylic polymer solution having a weight average molecular weight of 1.16 million. The glass transition temperature of the obtained acrylic polymer was 225K.

The obtained acrylic polymer solution was diluted with ethyl acetate so that the solid content was 25% to prepare a diluted solution (I). In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser, 20 parts of 4-hydroxybutyl acrylate glycidyl ether, 20 parts of butyl acrylate and benzoyl parr with respect to 400 parts by weight of the diluted solution (I) Add 0.12 parts of oxide, introduce nitrogen gas with gentle stirring and replace with nitrogen for 1 hour, then keep the liquid temperature in the flask at around 65 ° C. for 4 hours, then perform polymerization reaction at 70 ° C. for 4 hours. And a graft polymer solution was obtained.

As a tackifier resin, 20 parts of YS Polystar S-145 (softening point 145 ° C., manufactured by Rashala Chemical Co., Ltd.), 2 phenylimidazole 2 with respect to 100 parts by weight of the solid content of the graft polymer solution thus obtained. An adhesive solution was prepared by blending 0.5 parts by weight of a trimethylolpropane adduct of hexamethylene diisocyanate (manufactured by Nippon Polyurethane Co., Ltd., Coronate HL).

  The adhesive solution was applied to a 38 μm polyethylene terephthalate film (MRF-38, manufactured by Mitsubishi Resin Co., Ltd.) subjected to silicone release treatment so that the thickness of the pressure-sensitive adhesive layer after drying was 40 μm. Dry for 3 minutes. Using a 25 μm polyethylene terephthalate film (S-10, Toray, Inc.) as a support, the above-mentioned pressure-sensitive adhesive layer was transferred to both sides, and further subjected to aging treatment at 50 ° C. for 3 days. A wearing tape was obtained.

(Example 5)
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser, 88 parts by weight of n-butyl acrylate, 10 parts of methoxyethyl acrylate, 2 parts by weight of 4-hydroxybutyl acrylate, 2 as a polymerization initiator , 2'-azobisisobutyronitrile with 0.1 parts by weight of ethyl acetate and 200 parts by weight of ethyl acetate were charged, nitrogen gas was introduced with gentle stirring, and the atmosphere was purged with nitrogen for 1 hour. A polymerization reaction was carried out for 10 hours while maintaining the vicinity to prepare an acrylic polymer solution having a weight average molecular weight of 1,200,000. The glass transition temperature of the obtained acrylic polymer was 228K.

The obtained acrylic polymer solution was diluted with ethyl acetate so that the solid content was 25% to prepare a diluted solution (I). In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser, 10 parts of 4-hydroxybutyl acrylate glycidyl ether and 10 parts of 2-ethylhexyl acrylate and benzoyl with respect to 400 parts by weight of the diluted solution (I) Add 0.12 parts of peroxide, introduce nitrogen gas with gentle stirring and purge with nitrogen for 1 hour, then keep the liquid temperature in the flask at around 65 ° C for 4 hours, then polymerization reaction at 70 ° C for 4 hours To obtain a graft polymer solution.

20 parts of YS Polystar S-145 (softening point 145 ° C., manufactured by Rashara Chemical Co., Ltd.) as a tackifier resin with respect to 100 parts by weight of the solid content of the graft polymer solution thus obtained, 2 ethyl 4-methyl An adhesive solution was prepared by blending 4 parts by weight of imidazole and 0.5 part of trimethylolpropane adduct of tolylene diisocyanate (manufactured by Nippon Polyurethane Co., Ltd., Coronate L).

  The adhesive solution was applied to a 38 μm polyethylene terephthalate film (MRF-38, manufactured by Mitsubishi Resin Co., Ltd.) subjected to silicone release treatment so that the thickness of the pressure-sensitive adhesive layer after drying was 40 μm. Dry for 3 minutes. Using a 25 μm polyethylene terephthalate film (S-10, Toray, Inc.) as a support, the above-mentioned pressure-sensitive adhesive layer was transferred to both sides, and further subjected to aging treatment at 50 ° C. for 3 days. A wearing tape was obtained.

(Example 6)
Except that 15 parts of YS Resin SX-85 (softening point 85 ° C., manufactured by Yasuhara Chemical Co., Ltd.) was used as the tackifier resin with respect to 100 parts by weight of the solid content of the graft polymer solution obtained in Example 4. The same operation as in Example 1 was performed to obtain a double-sided adhesive tape of the present invention.

(Comparative Example 3)
In Example 4, a crosslinking agent and a thermosetting catalyst were blended in an acrylic polymer solution having a weight average molecular weight of 1.16 million consisting of 98 parts by weight of n-butyl acrylate and 2 parts by weight of 4-hydroxybutyl acrylate. Then, the same operation as in Example 1 was performed to obtain a double-sided adhesive tape of Comparative Example 3.

(Comparative Example 4)
In Example 4, a double-sided adhesive tape of Comparative Example 4 was obtained by blending a crosslinking agent without adding a thermosetting catalyst to the graft polymer and performing the same operation as in Example 1.

The evaluation results for Examples 4 to 6 and Comparative Examples 3 and 4 are shown in Table 2.

Claims (12)

100 parts by weight of a graft polymer obtained by graft polymerization of a chain containing a cyclic ether group-containing monomer to a (meth) acrylic polymer, 5 to 100 parts by weight of a tackifying resin having a softening point of 80 ° C. or higher, and a photocationic polymerization initiator Or it has the adhesive layer formed from the adhesive composition formed by containing 0.2-10 weight part of thermosetting catalysts, The double-sided adhesive tape characterized by the above-mentioned. The adhesive composition contains the cyclic ether group-containing monomer and other monomers, and the weight ratio of the cyclic ether group-containing monomer: other monomer is in the range of 90:10 to 10:90. The double-sided adhesive tape according to claim 1, wherein the double-sided adhesive tape is provided.   The double-sided adhesive tape according to claim 1 or 2, wherein the adhesive composition further contains a crosslinking agent.   The said adhesive composition contains 5-100 weight part of epoxy resins and / or oxetane resin further with respect to 100 weight part of said graft polymers, The any one of Claim 1 to 3 characterized by the above-mentioned. Double-sided adhesive tape.   The double-sided adhesive tape according to any one of claims 1 to 4, wherein the cyclic ether group-containing monomer is one or both of an epoxy group-containing monomer and an oxetane group-containing monomer. The double-sided adhesive tape according to any one of claims 1 to 5, wherein the (meth) acrylic polymer has a glass transition temperature of 250 K or less.   The said (meth) acrylic-type polymer contains 0.2-10 weight% of hydroxyl-containing monomers as a monomer unit with respect to this (meth) acrylic-type polymer whole quantity, The any one of Claim 1-6 characterized by the above-mentioned. Double-sided adhesive tape as described in 1. The graft polymer is composed of 2 to 50 parts by weight of the cyclic ether group-containing monomer and 5 to 50 parts by weight of the other monomer to 100 parts by weight of the (meth) acrylic polymer, and 0.02 to 5 parts by weight of peroxide. The double-sided adhesive tape according to any one of claims 1 to 7, which is obtained by graft polymerization in the presence.   9. The thermosetting catalyst is at least one selected from the group consisting of an imidazole compound, an acid anhydride, a phenol resin, a Lewis acid complex, an amino resin, a polyamine, and a melamine resin. The double-sided adhesive tape as described in any of the above.   The photocationic polymerization initiator is at least one selected from the group consisting of allylsulfonium hexafluorophosphate salt, sulfonium hexafluorophosphate salt, and bis (alkylphenyl) iodonium hexafluorophosphate. The double-sided adhesive tape according to any one of claims 1 to 8, wherein: It is a joining method to a to-be-adhered body using the double-sided adhesive tape in any one of Claim 1-10, Comprising: The said adhesive composition contains a photocationic polymerization initiator A bonding method comprising: irradiating the double-sided adhesive tape with light and attaching it to an adherend within a predetermined time. A method for bonding to an adherend using the double-sided adhesive tape according to any one of claims 1 to 10, wherein the adhesive composition contains a thermosetting catalyst, A bonding method, wherein the double-sided adhesive tape and the adherend are attached and heat-treated.