JP2002235064A - Adhesive tape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare an adhesive tape which has excellent heat resistance and can be adhered at room temperature without needing a complicated process such as a heat-pressing process, because of having a good pressure-adhesive property at the room temperature. SOLUTION: This adhesive tape comprises a photocurable adhesive composition comprising a polyester resin, a photo cation-polymerizable compound, and a photo cation polymerization initiator, and gives a photo-cured product having a glass transition temperature (Tg) of <=50 deg.C measured according to JIS K 7198.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure-sensitive adhesive tape comprising a photocurable pressure-sensitive adhesive composition which has pressure-sensitive adhesive properties at ordinary temperature and is cured by light irradiation.

[0002]

2. Description of the Related Art Conventionally, an adhesive has been used for fixing a semiconductor chip and a substrate and for fixing a flexible printed circuit board and the like in the electric and electronic fields. Since these adhesives pass through a “solder reflow furnace” for soldering in a manufacturing process, high heat resistance is required. As an adhesive having high heat resistance, for example, a liquid or solid epoxy resin is widely used. Further, in addition to the epoxy resin, a film-like adhesive has been proposed. In the case of a film-like adhesive, bonding is performed by heating and curing while sandwiching between adherends (for example, a special adhesive is used). JP 2000-285730 A).

However, when a liquid epoxy resin is used as an adhesive, the adhesive may exude from between adherends, and when a film-like adhesive is used, a heat press step is required at the time of curing. There was a problem with handling.

[0004]

Generally, in order to impart heat resistance to an adhesive, a resin having a high Tg (glass transition temperature) is used as a resin component of the adhesive. Since the region is at room temperature, the adherend may not be sufficiently wet due to the high elastic modulus at room temperature, and as a result, adhesion may be difficult. Therefore, in order to cause sufficient wetting at room temperature, it was necessary to temporarily raise the temperature of the adhesive to Tg or more by heating or the like.

[0005] In order to solve such a problem, the inventors of the present invention can sufficiently wet an adherend at room temperature by using an adhesive having a low Tg as an adhesive before curing, and then apply light irradiation. By controlling the Tg to 50 ° C. or less even after curing by the method described above, a high adhesive strength was realized at room temperature.
Further, they have found that it is possible to impart sufficient heat resistance by forming a crosslinked structure in the adhesive.

The present invention has been made to solve the above problems, and has as its object to have a good pressure-sensitive adhesive property at room temperature, so that a complicated process such as a heating press is not required at room temperature. An object of the present invention is to provide a pressure-sensitive adhesive tape which can be stuck, has no problem such as exudation of a pressure-sensitive adhesive, and has excellent heat resistance.

[0007]

The pressure-sensitive adhesive tape of the present invention comprises a photocurable pressure-sensitive adhesive composition comprising a polyester resin, a cationic photopolymerizable compound and a cationic photopolymerization initiator. And a glass transition temperature of the photocured product of the adhesive tape measured by using a dynamic viscoelasticity measuring device at a temperature rising rate of 3 ° C./min and a frequency of 10 Hz in accordance with JIS K 7198. (Tg) is 50 ° C. or less.

Hereinafter, the present invention will be described in detail. The photocurable pressure-sensitive adhesive composition (hereinafter referred to as pressure-sensitive adhesive composition) used in the present invention comprises a polyester resin, a photocationic polymerizable compound, and a photocationic polymerization initiator.

The polyester resin may have any structure such as aliphatic, alicyclic or aromatic, and is not particularly limited. Specifically, a reaction product of a dicarboxylic acid or a diester equivalent thereof and a diol can be used.

The dicarboxylic acid or its diester equivalent is a saturated fatty acid having 4 to 12 carbon atoms (one having a linear or branched chain, or a 5- or 6-membered cyclic structure). And / or an aromatic acid having 8 to 15 carbon atoms.

Preferred examples of the above fatty acids include, for example, succinic acid, glutaric acid, adipic acid, pimelic acid,
Suberic acid, azelaic acid, sebacic acid, 1,12-dodecane diacid, 1,4-cyclohexanedicarboxylic acid,
Examples thereof include 1,3-cyclopentanedicarboxylic acid, 2-methylsuccinic acid, 2-methylpentanedioic acid, and 3-methylhexanedioic acid.

Preferred examples of the aromatic acid include, for example, phthalic acid, terephthalic acid, isophthalic acid, 4,4'-
Benzophenone dicarboxylic acid, 4,4'-diphenylmethane dicarboxylic acid, 4,4'-diphenyl ether dicarboxylic acid, 4,4'-diphenyl thioether dicarboxylic acid,
4,4'-diphenylamine dicarboxylic acid and the like. The dicarboxylic acid preferably has a structure containing only carbon and hydrogen between two carboxyl groups. Two or more of these dicarboxylic acids may be used in combination. In order to increase the flexibility of the polyester resin, an aliphatic dicarboxylic acid such as adipic acid or sebacic acid may be copolymerized.

The diol is preferably a linear, branched or cyclic aliphatic diol having 2 to 12 carbon atoms, such as ethylene glycol, diethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol. Propylene glycol, 1,3-butanediol, 1,4-butanediol, α-methylbutanediol, α-dimethylbutanediol, 1,5-pentanediol, 2-methyl-2,4-pentanediol, 3-methyl Pentanediol, 1,6-hexanediol, 1,8-octanediol, cyclobutane-1,3-di (2′-ethanol), 1,4-dihydroxycyclohexane, cyclohexane-1,4-dimethanol, 1,10 -Decanediol, 1,12-dodecanediol, neopentyl glycol and the like. In addition, long-chain diols including polyoxyalkylene glycols and polytetramethylene ether glycols having an alkylene group having 2 to 9 carbon atoms (preferably having 2 to 4 carbon atoms) can also be used. These diols may be used alone or in combination of two or more.

In order to enhance the flexibility of the polyester resin, it is preferable to use a linear alcohol having a large number of carbon atoms as the diol.

In order to further increase the flexibility of the polyester resin, it is preferable to introduce a highly flexible ether bond into the polyester molecule. Examples of the method of introducing the ether bond include a method of polycondensing a polyether having a hydroxyl group at a terminal with a dicarboxylic acid and a diol. Examples of the polyether used here include polytetramethylene ether glycol, polypropylene glycol, polyethylene glycol and the like.

The above polyester resin is obtained by esterifying a carboxyl group of a carboxylic acid, transesterifying a portion of an ester bond, etherifying or esterifying a hydroxyl group of a hydroxyl group-containing compound, or alkylene oxide. May be any of the copolymerized polyethers. The above-mentioned polyester resins may be used alone or in combination of two or more.

The polyester resin used in the present invention comprises:
It is obtained by polycondensing the above dicarboxylic acid and diol using a suitable catalyst. The above-mentioned polyester resin sufficiently transmits light effective for initiating photo-curing, and preferably has a number average molecular weight of 10,000 to 100,000 and a softening temperature of 40 ° C. or higher according to a ring and ball measurement method. When the number average molecular weight is less than 10,000 and the softening temperature is less than 40 ° C., the pressure-sensitive adhesive tape described later easily flows, and it is difficult to maintain the tape state. On the other hand, if the number average molecular weight exceeds 100,000, the fluidity becomes insufficient, and it becomes difficult to form a tape.

The acid value of the polyester resin is 3 mgK
OH / g or less is preferred. When the acid value exceeds 3 mgKOH / g, a reaction between the polyester resin and the photocationic polymerizable compound occurs while the adhesive composition is stored, so that pressure-sensitive adhesiveness is not exhibited or curing is not performed. It may not progress. In addition, the wet heat resistance of the adhesive tape may decrease.

It is preferable that the Tg of the polyester resin itself used in the adhesive composition does not exceed 50 ° C. too much or is 50 ° C. or less. In other words, the polyester resin is not close to an elastic material such as general-purpose polyethylene terephthalate (PET).
Those having some flexibility are preferred. This is when the cationic photopolymerizable compound, which is a curing component described below, is cured,
This is because if the Tg of the polyester resin as the base resin is too high, the Tg of the photocured product tends to exceed 50 ° C.

Next, the cationic photopolymerizable compound will be described. As the photocationically polymerizable compound, an organic compound having a photocationically polymerizable functional group that can be made high molecular weight by cationic polymerization is used. The structure may be any structure such as aliphatic, alicyclic, and aromatic, and the photocationically polymerizable functional group may be located at the terminal of the molecular skeleton, at a side chain, or at any site in the molecular skeleton. Is also good. Examples of the photocationically polymerizable functional group include an epoxy group, an oxetane group, a vinyl ether group, an episulfide group, and an ethyleneimine group. Further, those which do not contain a functional group such as an amino group or the like which excessively suppresses the progress of cationic polymerization and makes curing of the adhesive incomplete are preferable.

The number of cationic photopolymerizable functional groups in the cationic photopolymerizable compound is preferably one or more per molecule, more preferably two or more. Here, the number of photocationically polymerizable functional groups per molecule is determined by dividing the total number of photocationically polymerizable functional groups in the photocationically polymerizable compound by the total number of molecules in the photocationically polymerizable compound.

The cationic photopolymerizable compound may be in any form such as liquid, semi-solid, or solid at room temperature, but it must have a boiling point of 200 ° C. or higher and be liquid or semi-solid at room temperature. Is preferred. When the boiling point is less than 200 ° C., the cationic photopolymerizable compound is volatilized from the obtained adhesive, and there is a possibility that the performance is reduced and the air pollution is caused. When the cationic photopolymerizable compound is solid at room temperature, the resulting adhesive may not exhibit pressure-sensitive adhesive properties at room temperature.

The above-mentioned cationic photopolymerizable compound is preferably a compound which sufficiently transmits light effective for initiating curing, and may be either crystalline or non-crystalline at room temperature. In order to enhance the pressure-bonding property, an amorphous material is preferable. To promote curing at room temperature, the glass transition temperature (Tg) of the cationic photopolymerizable compound
Is preferably 25 ° C. or less.

The cationic photopolymerizable compound may or may not be compatible with other components constituting the adhesive agent as long as it does not cause macrophase separation. Here, the macro-phase separation refers to a state in which any or all of the components are completely transparent and completely phase-separated, and is different from a state where the components are merely clouded by micro-phase separation.

Examples of the photocationically polymerizable compound include a cyclic ether compound such as an epoxy group-containing compound, an oxetane compound, and an oxolane compound, a cyclic ester compound, a vinyl ether compound, and a propenyl compound. May be used 2
More than one species may be used in combination.

Among the above cationic photopolymerizable compounds, an epoxy group-containing compound is particularly preferred. The epoxy group-containing compound refers to a compound having at least one oxirane ring that can be polymerized by cationic polymerization. The number of epoxy groups in the epoxy group-containing compound is preferably one or more per molecule, more preferably two or more per molecule. Here, the number of epoxy groups per molecule is determined by dividing the total number of epoxy groups in the epoxy group-containing compound by the total number of molecules in the epoxy group-containing compound.

The epoxy group-containing compound is not particularly limited. For example, bisphenol A
Epoxy resin such as epoxy resin, bisphenol F epoxy resin, bisphenol AD epoxy resin, bisphenol S epoxy resin, etc .; novolak epoxy resin such as phenol novolak epoxy resin, cresol novolak epoxy resin, etc .; Aromatic epoxy resins such as glycidyl ether and their water additives and bromides;
3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 3,4-epoxy-2-methylcyclohexylmethyl 3,4-epoxy-2-methylcyclohexanecarboxylate, bis (3,4-epoxycyclohexyl) Adipate, bis (3,4-epoxycyclohexylmethyl) adipate, bis (3,4-epoxy-6-methylcyclohexylmethyl) adipate, 2- (3,4-epoxycyclohexyl-5,5-spiro-3,4- Alicyclic epoxy resins such as epoxy) cyclohexanone-meta-dioxane, bis (2,3-epoxycyclopentyl) ether (trade name “EHPE-3150”, manufactured by Daicel Chemical Industries, softening temperature: 71 ° C.); Diglycidyl ether of butanediol, 1,6 Diglycidyl ethers of hexanediol, triglycidyl ether of glycerin, triglycidyl ether of trimethylolpropane, diglycidyl ether of polyethylene glycol, diglycidyl ether of polypropylene glycol, 2 carbon atoms
Examples thereof include aliphatic epoxy resins such as polyoxyalkylene glycol having an alkylene group having 9 (preferably 2 to 4 carbon atoms) and polyglycidyl ether of a long-chain polyol including polytetramethylene ether glycol.

Further, diglycidyl phthalate,
Diglycidyl tetrahydrophthalate, diglycidyl hexahydrophthalate, diglycidyl-p
-Glycidyl ether of oxybenzoic acid and salicylic acid-
Glycidyl ester type epoxy resins such as glycidyl ester and glycidyl ester of dimer acid and hydrogenated products thereof; triglycidyl isocyanurate, N, N'-diglycidyl derivative of cyclic alkylene urea, N, N, O- of p-aminophenol Glycidylamine type epoxy resins such as triglycidyl derivatives, N, N, O-triglycidyl derivatives of m-aminophenol, and hydrogenated products thereof;
Copolymers of glycidyl (meth) acrylate and radically polymerizable monomers such as ethylene, vinyl acetate and (meth) acrylate; polymers mainly composed of conjugated diene compounds such as epoxidized polybutadiene or partially hydrogenated products thereof Epoxidized unsaturated carbon double bonds of polymer; "polymer block mainly composed of vinyl aromatic compound" such as epoxidized SBS and "polymer block mainly composed of conjugated diene compound or a part thereof A block copolymer having a “hydrogenated polymer block” in the same molecule, obtained by epoxidizing an unsaturated carbon double bond of a conjugated diene compound; one or more (preferably two or more) per molecule A) a polyester resin having an epoxy group, wherein a urethane bond or a polycaprolactone bond is introduced into the structure of the various epoxy group-containing compounds. Conventionally known various epoxy group-containing compounds such as urethane-modified epoxy resins and polycaprolactone-modified epoxy resins; rubber-modified epoxy resins obtained by adding rubber components such as NBR, CTBN, polybutadiene, and acrylic rubber to the above various epoxy group-containing compounds. Can be

The above-mentioned various epoxy group-containing compounds may be used alone or in combination of two or more.

The amount of the cationic photopolymerizable compound used is preferably from 10 to 100 parts by weight based on 100 parts by weight of the polyester resin. When the amount is less than 10 parts by weight, the ratio of the cross-linking component due to cationic polymerization is reduced, so that the heat-resistant adhesiveness after curing is reduced. When it exceeds 100 parts by weight, the adhesiveness to the adherend is reduced.

Next, the cationic photopolymerization initiator will be described. As the cationic photopolymerization initiator, any of an ionic photoacid generating type and a nonionic photoacid generating type can be used. The cationic photoinitiator of the ionic photoacid generation type is not particularly limited,
For example, aromatic diazonium salts, aromatic halonium salts,
Onium salts such as aromatic sulfonium salts; and organic metal complexes such as iron-allene complexes, titanocene complexes, and allylsilanol-aluminum complexes. Among them, an aromatic iodonium salt, an aromatic sulfonium salt, and a metallocene salt are preferable, and an aromatic sulfonium salt is more preferable. These ionic photoacid generating type photocationic polymerization initiators may be used alone or in combination of two or more.

By incorporating the above-mentioned ionic photoacid generating type cationic photopolymerization initiator, the adhesive tape described later is rapidly cured by irradiation with light having a wavelength of 200 to 400 nm, and It also has excellent storage stability when storing the adhesive tape.

Aromatic iodonium salts, aromatic sulfonium salts and metallocene salts effective as the above-mentioned ionic photoacid generating type cationic photopolymerization initiator are described, for example, in US Pat. No. 4,256,828 and US Pat. No. 5,089,536. It is disclosed in Japanese Unexamined Patent Publication No. Hei 6-306346.

Of the above-mentioned ionic photoacid-generating type photocationic polymerization initiators, aromatic iodonium salts and aromatic sulfonium salts do not generate cations under light outside the ultraviolet region, but they do not contain aromatic amines or colored aromatic polyamines. By using a known sensitizer such as a cyclic hydrocarbon in combination, cations can be generated even in the near ultraviolet region or visible region. Also,
When a metallocene salt is used, a reaction accelerator such as an oxalate ester of tertiary alcohol may be used in combination.

Specific examples of the above-mentioned ionic photoacid generating type cationic photopolymerization initiator include, for example, trade names “ADEKA OPTOMER SP150” and “ADEKA OPTOMER SP17”.
0 "(all manufactured by Asahi Denka Kogyo KK), trade name" UVE-1 "
014 "(manufactured by General Electric Co., Ltd.) and trade name" CD-1012 "(manufactured by Sartomer Co., Ltd.).
These may be used alone or in combination of two or more.

The above-mentioned nonionic photoacid generating type cationic photopolymerization initiator is not particularly limited.
Examples thereof include nitrobenzyl ester, sulfonic acid derivative, phosphoric acid ester, phenolsulfonic acid ester, diazonaphthoquinone, N-hydroxyimidophosphonate, and the like, and these may be used alone or two or more kinds may be used in combination. .

The above cationic photopolymerization initiators may be used alone or in combination of two or more.

The amount of the cationic photopolymerization initiator used is preferably 0.1 to 10 parts by weight based on 100 parts by weight of the total amount of the polyester resin and the cationically polymerizable compound.
When the amount used is less than 0.1 part by weight, the cationic photopolymerization does not proceed sufficiently, or the curing is too slow. When the amount exceeds 10 parts by weight, the curing is too fast, so that it is difficult to bond the adherend. Become.

Light is generally used as energy applied to activate the above-mentioned cationic photopolymerization initiator, but an electron beam or the like may be used instead of light. As the light, for example, microwave, infrared light, visible light, ultraviolet light, X
Among them, ultraviolet rays, γ rays and the like can be mentioned, and among them, ultraviolet rays which are easy to handle and can obtain relatively high energy are preferable, and ultraviolet rays having a wavelength of 200 to 400 nm are more preferable.

Examples of the light source for supplying the ultraviolet rays include a carbon arc, a mercury vapor arc, a fluorescent lamp, an argon globe lamp, a halogen lamp, an incandescent lamp, a low-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a flash UV lamp, and a deep UV lamp. Lamps, xenon lamps, tungsten filament lamps, solar rays and the like.

The amount of light irradiation varies depending on the amount of each component constituting the adhesive composition, coating thickness, light irradiation source, etc., but is effective for generating cations from the photocationic polymerization initiator. 0.01-100 J / c
m ² is preferred.

The above-mentioned adhesive composition may contain an aliphatic hydroxyl group-containing compound, a thermoplastic resin, an adhesion improver, a filler, a reinforcing material, a softener, if necessary, as long as its performance is not impaired.
Plasticizers, viscosity modifiers, thixotropic agents, stabilizers, antioxidants, coloring agents, dehydrating agents, flame retardants, antistatic agents, foaming agents, fungicides and the like may be added. These may be used alone or in combination of two or more.

The aliphatic hydroxyl group-containing compound may be in any state of a monomer, an oligomer and a polymer. The aliphatic hydroxyl group may be in any position at the terminal of the molecular skeleton, in the side chain, or at any site in the molecular skeleton. Good. Further, the number of aliphatic hydroxyl groups is preferably one or more per molecule, more preferably two or more. Here, the number of aliphatic hydroxyl groups per molecule is determined by dividing the total number of aliphatic hydroxyl groups in the aliphatic hydroxyl group-containing compound by the total number of molecules in the aliphatic hydroxyl group-containing compound.

Examples of the aliphatic hydroxyl group-containing compound include polyhydroxyalkane, alkylene glycol, polyoxyalkylene glycol having an alkylene group having 2 to 9 carbon atoms (preferably having 2 to 4 carbon atoms), and polytetramethylene ether glycol. Long-chain polyols containing, for example, hydroxyl-terminated polyalkadiene, hydroxyl-terminated polyesters other than the above polyester resins, hydroxyl-terminated polycaprolactone, hydroxyl-terminated polycarbonate, acrylic polyol, (partial) saponified ethylene-vinyl acetate copolymer, polyvinyl Examples include alcohols, castor oil, ketone resins, xylene resins, and copolymers and modified products of these aliphatic hydroxyl group-containing compounds. These may be used alone or in combination of two or more.

The amount of the compound containing an aliphatic hydroxyl group is as follows:
The amount is preferably such that the ratio of the number of aliphatic hydroxyl groups to the number of cationic photopolymerizable functional groups in the obtained adhesive is 10 or less. If the ratio of the number of the aliphatic hydroxyl groups to the number of the cationic photopolymerizable functional groups exceeds 10, the heat-resistant adhesiveness of the obtained adhesive may be insufficient.

The form of the above-mentioned aliphatic hydroxyl group-containing compound may be any of liquid, semi-solid and solid at room temperature, but is preferably liquid and semi-solid at room temperature and has a boiling point of 200 ° C. or more. . When the boiling point is less than 200 ° C., the cationic photopolymerizable compound is volatilized from the obtained adhesive, and there is a possibility that the performance is reduced and environmental pollution is caused. If the aliphatic hydroxyl group-containing compound is solid at room temperature, the resulting adhesive may not exhibit pressure-sensitive adhesive properties at room temperature. When accelerating the curing at room temperature, Tg is 2
It is preferable to use an aliphatic hydroxyl group-containing compound having a temperature of 5 ° C. or lower.

Examples of the thermoplastic resin include polyolefin resins such as ethylene-vinyl acetate copolymer;
Block polymers such as styrene-butadiene-styrene block copolymers; acrylic copolymers; polycaprolactone resins; polycarbonate resins;
Terpene resins; styrene resins; tackifying resins such as petroleum resins; and various thermoplastic resins generally used such as waxes. These may be used alone or in combination of two or more. You may use together.

Examples of the adhesion improver include a silane coupling agent, a titanium coupling agent, an aluminum coupling agent and the like. These may be used alone or in combination of two or more. Good.

Examples of the filler include inorganic fillers such as calcium carbonate, magnesium carbonate, clay, talc, titanium oxide, and asbestos; fibers such as rayon fiber, acrylic fiber, nylon fiber, glass fiber, carbon fiber, and cellulose. Hollow fillers such as glass balloons, shirasu balloons, vinylidene chloride balloons, and acrylic resin balloons; organic spherical bodies such as nylon beads, acrylic resin beads, and silicon beads; urea melamine resin powder, acrylic resin powder, phenol resin powder, and the like. Synthetic resin powder;
Conventionally known various fillers such as natural powders such as wood flour and fruit husk powder, and surface-treated products thereof are exemplified. These may be used alone or in combination of two or more.

As the various components contained in the above-mentioned adhesive composition, any compatible or incompatible component can be used as long as it does not cause macrophase separation with other constituent components.

The various components contained in the above-mentioned adhesive composition have functional groups such as aromatic hydroxyl groups and (anhydrous) carboxyl groups which can react with the cationic photopolymerizable functional groups during storage. Those not containing are preferred. These various components are preferably those that do not decompose or volatilize during storage or light irradiation, and are preferably those that can sufficiently transmit light necessary for the initiation of curing. The various components may be either crystalline or non-crystalline at room temperature, but are preferably non-crystalline in order to increase the pressure-sensitive adhesiveness at room temperature. Further, it is preferable that the various components do not contain a functional group such as an amino group, which excessively suppresses the progress of cationic polymerization and inhibits the curing of the adhesive.

In the pressure-sensitive adhesive composition, the polyester resin is preferably a polycondensate containing an aliphatic carboxylic acid and / or polytetramethylene ether glycol.
Those composed of a polycondensate containing bisphenol A are preferred.

Hereinafter, a method for producing the adhesive tape will be described. The above-mentioned adhesive composition comprises a homodisper, a homomixer, a universal mixer, a planetarium mixer, a kneader, a general-purpose mixer such as a three-roll mixer, and forms the adhesive composition at room temperature or under heating. It is obtained by uniformly mixing predetermined amounts of the respective components. Such mixing is preferably performed in a state where light is blocked. In the production of the adhesive composition, kneading of each component may be carried out without a solvent, for example, in an inert solvent such as aromatic hydrocarbon, acetate, ketone and the like.

In the production of the adhesive composition, when the water content of each component increases, the progress of curing after irradiating the obtained adhesive tape with light may be inhibited.
If necessary, it is preferable to remove the water in each component in advance. The method for removing water is not particularly limited, and examples thereof include dehydration by mixing with a molecular sieve or the like, heat dehydration with an oven or a heater, and dehydration under reduced pressure. In addition, kneading of each component may be usually performed under atmospheric pressure, but it is preferable to perform kneading under a reduced pressure atmosphere or an inert gas atmosphere such as nitrogen gas in order to avoid mixing of moisture.

The adhesive composition obtained by the above production method may be applied to an adherend as it is and then cured by cationic photopolymerization. However, better handling workability and simplicity can be obtained. In order to obtain the adhesive, it is preferable that the adhesive composition is previously processed into a sheet and used as an adhesive tape. As a method of processing into an adhesive tape, for example, on a release-treated sheet-like support, a bar coating method, a roll coating method, a gravure coating method, an extrusion coating method or the like, the adhesive composition After coating, a method of protecting the coated surface with a release sheet such as polyethylene, for example, and winding it up may be used. When processing into such an adhesive tape, when the adhesive is solid or semi-solid, or has a high viscosity even in a liquid state and is difficult to apply, it is diluted with, for example, an organic solvent. Alternatively, the viscosity may be reduced by heating and melting.

Examples of the support and the release sheet include polyethylene terephthalate (PET), polyethylene naphthalate, polyethylene, polypropylene, polycarbonate, nylon, polyarylate, polysulfone, polyether sulfone, polyether ether ketone, polyphenylene sulfide, and the like. Examples include polystyrene, polyacryl, polyvinyl acetate, diacetyl cellulose, triacetyl cellulose, and the like.

The thickness of the support or release sheet is 10 μm.
m or more. When the thickness is less than 10 μm, the strength is reduced, and there is a possibility that the film may be broken during use. The thickness of the adhesive tape itself is 1 to 2000 μm.
It is preferred that When the thickness is less than 1 μm, irregularities on the surface of the adherend may greatly affect the adhesiveness, and when it exceeds 2000 μm, the curing time may be extremely long.

After the adhesive tape is inserted, for example, between adherends, it can be adhered by irradiating ultraviolet rays having a wavelength of 200 to 400 nm and photo-curing.

The glass transition temperature (Tg) of the photo-cured product of the above-mentioned pressure-sensitive adhesive tape is set to 50 ° C. or less because if it exceeds 50 ° C., the pressure-sensitive adhesive property at room temperature may be insufficient. The above-mentioned glass transition temperature (Tg) was measured by using a dynamic viscoelasticity measuring device in accordance with JIS K 7198, at a heating rate of 3 ° C. /
And the loss tangent (tan) measured at a frequency of 10 Hz.
δ) is represented by the peak value. The photo-cured product of the adhesive tape is obtained by irradiating the adhesive tape with ultraviolet light having a wavelength of 365 nm so as to have an irradiation amount of 2400 mJ / cm ² .

[0060]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, advantages of the present invention will be described with reference to examples and comparative examples of the present invention. (Example 1) 80 parts by weight of a polyester resin, 20 parts by weight of an epoxy resin [Epicoat 828 (component: bisphenol A diglycidyl ether) manufactured by Yuka Shell Epoxy Co., Ltd.], and a cationic photopolymerization initiator (manufactured by Asahi Denka Kogyo KK) 1 part by weight of Adeka Optomer SP170) and 150 parts by weight of methyl ethyl ketone (solvent) are supplied to a homodisper type stirring mixer ("Homodisper L type" manufactured by Tokushu Kika Co., Ltd.), and the mixture is uniformly stirred at a stirring speed of 3000 rpm. The mixture was mixed to prepare an adhesive composition. Incidentally, as the polyester resin, terephthalic acid 25 mol% as a polyvalent carboxylic acid component was used.
And a copolymer obtained by copolymerizing 25 mol% of isophthalic acid with 17.5 mol% of ethylene glycol as a polyhydric alcohol component, 17.5 mol% of an ethylene glycol adduct of bisphenol A, and 15 mol% of polytetramethylene ether glycol. did.

Example 2 As a polyester resin, 25 mol% of terephthalic acid and 25 mol% of isophthalic acid as polyvalent carboxylic acid components, and 17.5 mol% of ethylene glycol and 17.5 mol of neopentyl glycol as polyhydric alcohol components. A pressure-sensitive adhesive composition was obtained in the same manner as in Example 1 except that 80 parts by weight of a copolymer of mol% and polytetramethylene ether glycol 15 mol% was used.

Example 3 The procedure was carried out except that "UE3400" (a polycondensate of terephthalic acid, isophthalic acid, sebacic acid, ethylene glycol and neopentyl glycol) manufactured by Unitika was used as the polyester resin. An adhesive composition was obtained in the same manner as in Example 1.

(Comparative Example 1) The procedure was the same as in Example 1 except that 80 parts by weight of "UE3500" (a polycondensate of terephthalic acid, isophthalic acid, sebacic acid, ethylene glycol and neopentyl glycol) manufactured by Unitika was used as the polyester resin. An adhesive composition was obtained in the same manner as in Example 1.

The pressure-sensitive adhesive compositions of the above Examples and Comparative Examples were coated on a release-treated surface of a 50 μm-thick PET film support having been subjected to a release treatment by using a bar coater to have a thickness after coating. Coating and drying were performed to a thickness of 50 μm to provide an adhesive layer. Next, a release-treated surface of a PET film that had been subjected to silicone release treatment as a protective film was laminated on the adhesive layer to obtain a three-layer laminate. The performance of the following items was evaluated for the adhesive layer (adhesive tape) of the three-layer laminate, and the results are shown in Table 1.

(1) Measurement of Glass Transition Temperature (Tg) The PET film of the above three-layer laminate was peeled off, and an ultraviolet ray having a wavelength of 365 nm was applied to the surface of the adhesive tape using an ultra-high pressure mercury lamp with an irradiation amount of 2400 mJ / cm ² . Irradiation was performed so as to obtain light curing. According to JIS K 7198, this photocured product was heated at a rate of 3 ° C./min and a frequency of 10 Hz using a dynamic viscoelasticity measuring device (“Viscoelastic Spectrometer DVA-200” manufactured by IT Measurement Control Co., Ltd.). The peak value of the loss tangent (tan δ) measured under the conditions was determined as the glass transition temperature (T
g).

(2) Room-Temperature Adhesion While the protective film of the adhesive tape was peeled off, it was laminated at room temperature on a glass epoxy plate. Then, PET
The film support was peeled off, and an ultraviolet ray having a wavelength of 365 nm was irradiated on the surface of the adhesive tape using an ultra-high pressure mercury lamp at a dose of 2400 m.
After irradiation to J / cm ² , a polyimide film was immediately laminated on the surface of the adhesive tape at room temperature to obtain a laminate (glass epoxy plate / adhesive tape / polyimide film). The adhesiveness between the glass epoxy plate / adhesive tape and between the adhesive tape / polyimide film of the laminate was evaluated by visual observation according to the following criteria. Good: good adhesion without peeling between the glass epoxy plate / adhesive tape and between the adhesive tape / polyimide film. Poor: Lamination between the glass epoxy plate / adhesive tape and / or the adhesive tape / polyimide film was easily peeled off.

(3) Evaluation of Solder Heat Resistance The same laminate as in the above (2) was placed in an oven at 110 ° C. for 3 hours.
After curing for 0 minutes, it was left for 1 day in an atmosphere of 23 ° C. and 65% RH, and then placed in a “solder bath” set at a temperature of 220 ° C. so that the polyimide film side was on the lower side, and an adhesive tape was used. Was visually observed, and the number of seconds until foaming was measured.

[0068]

[Table 1]

[0069]

Since the adhesive tape of the present invention has the above-mentioned structure, it can be bonded at room temperature without requiring a complicated process such as a hot press, and can be used at a room temperature. No problems such as seepage occur. In addition, the cured adhesive tape has excellent heat resistance and good stress relaxation compared to conventional high Tg type adhesives. Can be

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J004 AA15 AB01 AB07 BA02 DA02 DA03 DB01 FA05 FA08 4J040 EC062 EC072 EC102 EC362 EC372 EC402 EC412 ED041 FA012 GA07 HB42 HB43 HB44 JA09 JB07 JB09 KA16 LA01 LA02 LA06 MA02 MA10 MB03 NA19 PA32

Claims (3)

[Claims] 1. An adhesive tape comprising a photo-curable adhesive composition containing a polyester resin, a cationic photo-polymerizable compound and a cationic photo-polymerization initiator, wherein a photo-cured product of the adhesive tape is provided. According to JIS K 7198, using a dynamic viscoelasticity measuring device, heating rate 3 ° C./min, frequency 1
The glass transition temperature (Tg) measured under the condition of 0 Hz is 5
An adhesive tape having a temperature of 0 ° C. or lower. 2. The adhesive tape according to claim 1, wherein the polyester resin comprises a polycondensate containing an aliphatic carboxylic acid and / or polytetramethylene ether glycol. 3. The adhesive tape according to claim 1, wherein the cationic photopolymerizable compound comprises a polycondensate containing bisphenol A.