JP2683448B2 - Resin composition for pressure-sensitive adhesive and pressure-sensitive adhesive tape or sheet using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Industrial field of application) The present invention provides a resin for an adhesive that is excellent in adhesive properties such as adhesive strength and cohesive strength without using a crosslinking agent such as polyisocyanate. The present invention relates to a composition and an adhesive tape or sheet produced by using the composition.

(Prior Art) Acrylic pressure-sensitive adhesives that have been generally used are mainly alkyl esters of acrylic acid or methacrylic acid, such as butyl acrylate and 2-ethylhexyl acrylate, whose glass transition temperature in the polymer is room temperature or lower. In order to increase cohesive force and adhesive force, monomers that increase the glass transition temperature of polymers such as vinyl acetate and acrylonitrile, and monomers that have functional groups such as hydroxyl groups, carboxyl groups and amide groups have been copolymerized. It is mainly composed of polymers.

However, it is difficult to balance cohesive force and adhesive force and to provide heat resistance with only these polymers. In actual adhesives, phenol resin, rosin resin, petroleum resin, and modified resins thereof are used. The cohesive strength is improved by adding a tackifier or by reacting a cross-linking agent such as polyisocyanate with a functional group in the acrylic polymer.

(Problems to be Solved by the Invention) In the case of crosslinking with polyisocyanate, since the reaction is started at the time of adding the polyisocyanate into the resin, the addition must be performed immediately before the coating of the adhesive. In addition, it is difficult to use polyisocyanate having a high reactivity in order to prevent the reaction from progressing excessively during coating and increasing the viscosity to make the coating difficult.

Therefore, an aging period is required to allow the crosslinking to proceed sufficiently and to stabilize the performance of the adhesive tape or sheet. If this is carried out at room temperature, it will take a period of several days to several weeks, and during this period, a space for storing the manufactured tape or sheet is required.

Moreover, since it cannot be manufactured immediately, it is necessary to have some inventory.

On the other hand, there is also a method of accelerating the cross-linking at a high temperature, but it requires a considerable amount of energy for heating both when it is applied after coating and when it is performed on the coating line, and the time is also limited.

Also, when other cross-linking agents are used, there are the same problems as described above, and the functional groups in the polymer serving as cross-linking points are limited, which makes it difficult to handle. As described above, the conventional method for improving the cohesive force with the crosslinking agent has a problem in manufacturing.

The present invention solves the above problems in the conventional resin composition, that is, some problems caused by using polyisocyanate or the like as a crosslinking agent,
It is intended to provide a resin composition for pressure-sensitive adhesive having sufficiently excellent pressure-sensitive adhesive strength and a pressure-sensitive adhesive tape or sheet using the same.

[Configuration of the invention]

(Means for Solving the Problem) The present invention provides a polyester oligomer (A) obtained by using a cyclic acid anhydride (a) and an epoxide (b) having an ethylenically unsaturated group as the whole amount or a part of the epoxide as a main raw material. And a pressure-sensitive adhesive acrylic polymer (B) are mixed, and a reactive resin composition for pressure-sensitive adhesive, and a polymerization initiator (C) are mixed with the resin composition, if necessary,
An adhesive tape or sheet characterized by being produced by reacting an unsaturated group by heating or light irradiation after coating or impregnating a substrate.

When the polyester oligomer (A) is obtained in the present invention, in order to smoothly proceed the initial reaction and adjust the molecular weight of the polyester oligomer (A) to be formed, a reaction such as a hydroxyl group or a primary, secondary, or tertiary amino group is performed. It is necessary to use a compound having a functional group as the starting point of.

Among these, it is generally preferable to use a compound having a hydroxyl group because of the properties of the raw materials and products and the ease of control during the reaction.

Compounds having a hydroxyl group include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2
-Aliphatic saturated alcohols such as butanol, pentanol and hexanol, aliphatic unsaturated alcohols such as allyl alcohol, crotyl alcohol and propargyl alcohol, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, N-methylol acrylamide and other hydroxyl group-containing (meth) acrylates or (meth) acrylamides, and cycloaliphatic alcohols such as cyclopentanol and cyclohexanol , Aromatic alcohols such as benzyl alcohol, cinnamyl alcohol,
Heterocyclic alcohols such as furfuryl alcohol and tetrahydrofurfuryl rucol, ethylene glycol, propylene glycol, 1,4-butylene glycol, butenediol, hexanediol, cyclohexanediol,
Compounds having alcoholic or phenolic hydroxyl groups such as bisphenol A, diols such as diethylene glycol, triols such as glycerin and trimethylolpropane, phenols such as phenol, o-cresol, m-cresol and p-cresol .

However, among these, the above-mentioned diols and carboxyl groups such as 2-hydroxy-n-acetic acid, 3-hydroxy-n-butyric acid, p-hydroxybenzoic acid, hydroxypivalic acid, salicylic acid, vanillic acid, and 12-hydroxystearic acid. And a hydroxyl group at the same time, or two or more functional groups such as ethanolamine, 1-amino-2-propanol, o-aminophenol, m-aminophenol, p-aminophenol and other compounds having an amino group and a hydroxyl group at the same time. Compounds having groups are preferred.

In the present invention, the cyclic acid anhydride (a) is an intramolecular anhydride of polyvalent carboxylic acid, and is a saturated or unsaturated aliphatic polyvalent carboxylic acid anhydride, alicyclic polyvalent carboxylic acid anhydride, aromatic There are polyvalent carboxylic acid anhydrides, etc., or some of these substituted with saturated or unsaturated hydrocarbon groups, aromatic ring groups, halogen atoms, heterocyclic groups, etc. Succinic acid, phthalic anhydride,
Maleic anhydride, itaconic anhydride, glutaric anhydride, dodecenyl succinic anhydride, chlorendecic anhydride, pyromellitic anhydride, trimellitic anhydride, cyclopentanetetracarboxylic dianhydride, hexahydrophthalic anhydride,
Methylhexahydrophthalic anhydride, tetramethylene maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, methylendomethylenetetrahydrophthalic anhydride, 5- (2,5-dioxotetrahydroxy Frill)-
3-methyl-3-cyclohexene-1,2-dicarboxylic acid anhydride, methyl nadic acid anhydride, benzophenone tetracarboxylic acid anhydride, glycerol tris (anhydrotrimellitate), ethylene glycol bis (anhydrotrimellitate), etc. is there.

Among them, it is preferable to use dicarboxylic acid or tricarboxylic acid anhydride which does not form a crosslinked structure.

In the present invention, examples of the epoxide (b) having an ethylenically unsaturated group include glycidyl (meth) acrylate, glycidyl cinnamate, allyl glycidyl ether, vinylcyclohexene monoepoxide, and 1,3-butadiene monoepoxide. Further, as the epoxide having no ethylenically unsaturated group, which is optionally used together with these, there are epichlorohydrin, phenylglycidyl ether, styrene oxide, cyclohexene oxide, butene oxide and the like.

These epoxides may be substituted with saturated or unsaturated hydrocarbon groups, aromatic ring groups, halogen atoms, heterocyclic groups and the like.

A compound having the above hydroxyl group, a cyclic acid anhydride (a),
By reacting the epoxide (b) having an ethylenically unsaturated group and, if necessary, the epoxide having no unsaturated group, a polyester oligomer (A) having an ethylenically unsaturated group is obtained.

The reaction is carried out in the presence or absence of a suitable solvent, N, N-
Tertiary amines such as dimethylbenzylamine, triethylamine, tributylamine, N, N-diethylaniline, N, N-dimethylaniline, etc. are used as a catalyst as needed, and hydroquinone, for protecting the ethylenically unsaturated group, It can be carried out in the state where a radical polymerization inhibitor such as hydroquinone monomethyl ether, tert-butyl catechol, p-benzoquinone is added.

In addition, a polyester oligomer having no unsaturated group can be obtained by using only an epoxide having no ethylenically unsaturated group in the same manner, and may be used in combination with an oligomer having an unsaturated group if necessary. You can

In the reaction, the hydroxyl group of the compound having a hydroxyl group and the acid anhydride group of the cyclic acid anhydride (a) first react preferentially, and then the carboxyl group generated by this reaction and the epoxy group of the epoxide (b) are reacted. React with each other to generate a secondary hydroxyl group. Furthermore, the reaction similar to the above can be successively carried out so that the generated hydroxyl group reacts with the acid anhydride group of the cyclic acid anhydride (a).

In this reaction, by adjusting the amounts of the cyclic acid anhydride (a) and the epoxide (b) that are reacted with the amount of the compound having a hydroxyl group, a desired number of ethylene having a compound having a hydroxyl group as a terminal can be obtained. A polyester oligomer (A) having a desired length having a functional unsaturated group can be prepared.

When the cyclic acid anhydride (a) is a dicarboxylic acid anhydride, the proportion of each compound is 1 to 20 moles of the cyclic acid anhydride (a) and 1 mole of the compound having a hydroxyl group, and the epoxide (b). ) It is preferable that the cyclic acid anhydride (a) and the epoxide (b) are reacted at a ratio of 1 to 20 mol, and at a ratio of about equimolar. When the cyclic acid anhydride (a) is a tricarboxylic acid, a compound 1 having a hydroxyl group
1 to 10 moles of cyclic acid anhydride (a) and 1 to 20 moles of epoxide (b) relative to 1 mole of epoxide (b) to 1 mole of cyclic acid anhydride (a). It is preferable to react at a ratio of 2 mol.

When the amount of the cyclic acid anhydride (a) or epoxide (b) reacted with 1 mol of the compound having a hydroxyl group is less than 1 mol, the obtained polyester oligomer (A) has a low molecular weight or has a hydroxyl group. There is a residue of the compound with which the required properties cannot be obtained. On the contrary, when the amount of cyclic acid anhydride (a) or epoxide (b) exceeds 20 mol, it becomes difficult to control the reaction,
The molecular weight tends to be too high, and the required properties tend not to be obtained.

As described above, the polyester oligomer (A) obtained here can use various compounds as a raw material for the compound having a hydroxyl group, the cyclic acid anhydride (a), and the epoxide (b), and the ratio thereof is By changing the molecular weight, it is possible to make one with an arbitrary length having a relatively uniform molecular weight.

It is also possible to use a mixture of two or more kinds of each compound.

In particular, regarding the epoxide, both those having an ethylenically unsaturated group and those not having an ethylenically unsaturated group can be used in an arbitrary ratio. Therefore, it is possible to prepare oligomers having various characteristics depending on the purpose of use.

Therefore, when it is added to the tacky polymer as in the present invention, it is necessary to change the kind of the oligomer and its blending ratio depending on the use, from those acting as a tackifier to those acting as a filler. It is possible to give various properties to the composition, and by adjusting the degree of reactivity depending on the type and proportion of epoxide, the cohesive force after the reaction can be improved as much as necessary, and the balance with other properties can be improved. It is possible to put it in a detached state.

In the present invention, the adhesive acrylic polymer (B) means a hydroxyl group, a tertiary amino group, a carboxyl group, an amide group, N-
It has a functional group such as a substituted amide group and a nitrile group, and is generally used as an acrylic resin for adhesives.

Further, even if the polymer alone has poor adhesiveness, a polymer showing good adhesive properties by adding the polyester oligomer (A) or other resin can be used as the polymer (B) of the present invention.

The acrylic polymer having these functional groups includes one or several kinds of monomers having a hydroxyl group, a tertiary amino group, a carboxyl group, an amide group, an N-substituted amide group, a nitrile group, an alkyl (meth) acrylate, Examples thereof include copolymers with monomers such as vinyl acetate, vinyl propionate, vinyl ether and styrene.

As the monomer having a hydroxyl group, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, N
There are methylol acrylamide, allyl alcohol and the like, and examples of the monomer having a tertiary amino group include dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylamide and the like.

Examples of the monomer having a carboxyl group include acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid and citraconic acid.

Examples of the monomer having an amide group or an N-substituted amide group include acrylamide, methacrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-ethoxymethyl (meth). ) Acrylamide, N-propoxymethyl (meth) acrylamide, N-butoxymethyl (meth)
Examples include acrylamide, N-tert-butyl acrylamide, N-octyl acrylamide, and diacetone acrylamide.

Examples of the monomer having a nitrile group include acrylonitrile, methacrylonitrile, crotononitrile, and fumaronitrile.

The alkyl (meth) acrylate is an alkyl (meth) acrylate such as methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate or octyl (meth) acrylate. .

In addition, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, and the like, and alkyl (meth) acrylate in which the alkyl group is substituted with an aromatic ring, a heterocyclic group, a halogen atom, and the like are generally used. The monomers used for the synthesis of the acrylic polymer can be used for the synthesis of the polymer of the present invention.

The reaction is an ordinary radical polymerization, and there is no limitation on the reaction method, and it can be carried out by a known polymerization method such as solution polymerization, bulk polymerization, emulsion polymerization, etc. However, it is easy to control the reaction and Solution polymerization is preferable because it can be operated.

As the solvent, any solvent such as methyl ethyl ketone, methyl isobutyl ketone, toluene, cellosolve, ethyl acetate, and butyl acetate may be used as long as the resin of the present invention can be dissolved. A single solvent or a mixture of a plurality of solvents may be used.

The polymerization initiator used in the polymerization reaction is also an organic peroxide such as benzoyl peroxide, acetyl peroxide, methyl ethyl ketone peroxide, lauroyl peroxide, or an azo initiator such as azobisisobutyronitrile. There is no particular limitation.

By mixing the unsaturated polyester oligomer (A) obtained by each reaction and the tacky acrylic polymer (B), a tacky resin having reactivity can be obtained.

It is sufficient to stir the mixture at room temperature until it becomes apparently uniform, but in order to further enhance the state of mutual mixing, heating and stirring at a temperature not higher than the boiling point of the solvent may be performed.

 The resin composition of the present invention is obtained as described above.

It is considered that the obtained composition probably has a micro phase separation structure because the compatibility between the polyester oligomer (A) and the tacky acrylic polymer (B) is not so good. It can be seen from the fact that some solutions have a particularly high concentration, and some of the solutions cause white turbidity when the composition is coated on a film.

However, it does not separate in a stationary state and maintains a uniform state. In general, when an oligomer having good compatibility is added, the cohesive force can be improved, but the cohesive force, particularly at high temperature, is decreased.
In the case of a resin composition having a microphase-separated structure as in the present invention, the composition is largely influenced by the composition of the oligomer (A) to be added, but the characteristic is that the cohesive force is not generally lowered.

In particular, when an oligomer having a high viscosity and a high softening point is used, an effect close to that of a filler is exhibited and the cohesive force can be greatly improved.

Furthermore, in the present invention, since the epoxide (b) having an ethylenically unsaturated group is used, all or part of the polyester oligomer (A) has an unsaturated group, and by reacting this with some method, The mobility of the oligomer (A) and the polymer (B) can be limited, and the cohesive force can be greatly improved as in the case of using the crosslinking agent.

Here, unlike the case where a crosslinking agent is used, the functional group in the polymer (B) is not used as a cross-linking point, so the adhesiveness of the resin composition does not decrease due to the decrease of the functional group, and the adhesive strength Can be kept.

For the above reasons, a pressure-sensitive adhesive tape or sheet having excellent cohesive strength and adhesive strength and having a good balance between them can be prepared from the composition of the present invention.

As the reaction method of the unsaturated group in the polyester oligomer (A), there are a method by electron beam irradiation, a heating in combination with an appropriate polymerization initiator (C), a light irradiation and the like. Although it is possible to cause the reaction to occur at room temperature depending on the selection of the polymerization initiator (C) and the accelerator, this is not the preferred method because it causes the same problems as the method using the conventional crosslinking agent.

Further, generally, light or electron beam irradiation is preferable from the viewpoint of reaction time and the like, but in the case where the pressure-sensitive adhesive layer is thick, heating may be preferable in order to sufficiently react the inside.

Polymerization initiator (C) used in the case of reaction by heating
Examples include dialkyl peroxides such as di-tert-butyl peroxide, tert-butyl cumyl peroxide, and dicumyl peroxide, diacyl peroxides such as acetylperoxide, lauroyl peroxide, and benzoyl peroxide, and methyl ethyl ketone peroxide. Ketone peroxides such as oxide, cyclohexanone peroxide, 3,3,5-trimethylcyclohexanone peroxide, and methylcyclohexanone peroxide, peroxyketals such as 1,1-bis (tert-butylperoxy) cyclohexane, tert-
Butylhydroperoxide, cumene hydroperoxide, 1,1,3,3-tetramethylbutylhydroperoxide, p-menthane hydroperoxide, diisopropylbenzene hydroperoxide, 2,5-dimethylhexane-2,5-dihydro Hydroperoxides such as peroxides, tert-butylperoxyacetate, tert-butylperoxy-2-ethylhexanoate, organic peroxides such as peroxyesters such as tert-butylperoxybenzoate, azobis Isobutyronitrile,
There is no particular limitation as long as it is a known compound such as an azo compound such as azobisvaleronitrile.

The polymerization initiator (C) is used in an amount of usually 0.1 to 15 parts by weight, preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the resin composition of the present invention.

When an organic peroxide having a low radical generation rate is used, N, N-dimethylbenzylamine, triethylamine, tributylamine, N, N-diethylaniline, N, N-dimethylaniline, N-phenyldiethanolamine, Tertiary amines such as N-phenyldiisopropanolamine, dimethyl-p-toluidine, triethanolamine, 4-phenylmorpholine, lithium, calcium, strontium, barium, cerium, zirconium, vanadium, molybdenum, manganese, iron, cobalt, Laurates, naphthenates, octylates, oleates of metals such as nickel, copper, zinc, tin and lead,
One or more metal compounds selected from fatty acid salts such as octenoate salts, resin acid salts such as rosin salts and chelate compounds such as acetylacetonate complex salts can be used as the accelerator.

Of these accelerators, tertiary amines are usually used in a proportion of 1 to 100 parts by weight per 100 parts by weight of organic peroxide, and metal compounds are added in an amount of 0.01 to 10 parts by weight per 100 parts by weight of organic peroxide. Used in proportion.

As the polymerization initiator (C) used in the case of light irradiation, benzoyl, benzoin methyl ether, benzoin ethyl ether, methyl o-benzoylbenzoate-p-
Benzoin such as benzoin ethyl ether, benzoin isopropyl ether, α-methylbenzoin, dimethylbenzyl ketal, trichloroacetophenone,
Acetophenones such as 2,2-diethoxyacetophenone, 2-hydroxy-2-methylpropiophenone, 2-
Propiophenones such as hydroxy-4′-isopropyl-2-methylpropiophenone, α-acyloxime ester, benzophenone, methylbenzophenone, p
-Chlorobenzophenone, p-dimethylaminobenzophenone and other benzophenones, 2-chlorothioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone and other thioxanthones, benzyl, dibenzosuberone, etc. EB Hardening Handbook-Raw Materials- "(December 1985, published by Kobunshi Publishing Co.) No. 67-
Page 73 or "Crosslinking Agent Handbook" edited by Fuzo Yamashita and Tosuke Kaneko (October 1981, published by Taiseisha), pages 582-593.

These polymerization initiators (C) may be used together with a promoter. Examples of such promoters include 4,4'-bis (diethylamino) benzophenone, ethyl N-dimethylaminobenzoate, diethylethanolamine, and glycine, and Kato Kiyomi Ed., Supra, pp. 67-73. What is described can be used.

When light having a relatively long wavelength such as ultraviolet rays or visible light is used as the light, it is preferable to use a polymerization initiator and, if necessary, an accelerator from the viewpoint of reaction efficiency.

The polymerization initiator (C) is used in an amount of usually 0.05 to 20 parts, preferably 0.5 to 10 parts, relative to 100 parts by weight of the resin composition of the present invention.

The resin composition to which these polymerization initiators (C) and the like are added is not reactive or has a considerably low reactivity until it is heated or irradiated with light. After adding, it is possible to store for a while until coating.

In addition to the unsaturated polyester oligomer (A) used in the present invention, an ethylenic unsaturation such as a (meth) acryloyl group other than the unsaturated polyester oligomer (A) used in the present invention is added to the resin composition of the present invention in order to adjust the adhesive property after the treatment such as heating or light irradiation. It is also possible to add a monomer or oligomer having a group.

Such monomers and oligomers include styrene, alkyl (meth) acrylate, (meth) acrylic acid, polyhydric alcohol poly (meth) acrylate, epoxy poly (meth) acrylate, oligoester poly (meth) acrylate, and polyurethane poly ( (Meth) acrylate, diallyl phthalate, diallyl isophthalate and the like.

The present invention is characterized by not using a cross-linking agent such as polyisocyanate, but when a particularly strong cohesive force and heat resistance are required for reasons such as applications, it is possible to add a cross-linking agent such as polyisocyanate. It doesn't matter.

As such polyisocyanate, (hydrogenated) tolylene diisocyanate, (hydrogenated) 4,4-diphenylmethane diisocyanate, hexamethylene diisocyanate and the like can be used.

In the resin composition of the present invention, a pigment, a dye, an inorganic filler, an organic solvent, an organic solvent, and
Metal powder such as silver powder, copper powder, nickel powder, carbon black, graphite, tackifier such as xylene resin and rosin resin, silane coupling agent and the like can be added.

In the production of pressure-sensitive adhesive tapes and sheets from the resin composition of the present invention, the treatment by heating or light irradiation may be carried out after leaving for a while after coating or immediately before use. After the reaction is complete, the resin composition is stable, and the tape, sheet, etc. produced under normal storage conditions show almost no alteration, the coating and lining are easy to perform, and it can be continuously performed on the production line. From the viewpoints of the above, it is preferable to perform the coating on the final substrate, immediately after the lining, or immediately after the coating on a release paper, a film or the like having a high releasability which serves as a temporary substrate.

However, when coating or impregnating a permeable base material such as a non-woven fabric, it may be necessary to wait until the material has sufficiently penetrated.

In the production of the adhesive tape or sheet according to the present invention, is it applied to a film, sheet, tape or the like such as a plastic film, paper, cellophane, cloth, non-woven fabric, metal foil, etc. as in the case of producing an ordinary adhesive tape or sheet? , Paper or cloth treated with silicone, polyethylene terephthalate film laminated paper, paper or cloth processed with low-adhesion resin, metal foil, plastic film, etc. The organic solvent is removed by drying, if necessary, and at this point heat treatment, light irradiation, etc. are mainly performed, and if necessary, it is cut into a double-sided or single-sided adhesive sheet or tape. For rayon, reinforcement and shock absorption, rayon,
Non-woven fabrics such as nylon, cloths such as cheesecloth, urethane,
Lining with foams such as acrylics, or by applying or impregnating the cloth or foams with the resin composition of the present invention as a core material, then performing treatments such as heating or light irradiation. by.

The tape or sheet base material, core material, etc. used here must be such that they do not significantly change in quality by treatment such as heating or light irradiation, or do not significantly interfere with the reaction.

In the present invention, the heat treatment is usually performed in an oven at 80 to 150 ° C. for about 3 to 20 minutes.

In the case of light irradiation, visible light from a sun or a fluorescent lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a metal halide lamp, a carbon arc lamp, an ultraviolet ray from a xenon lamp, or cobalt 60 is used. Gamma ray as a radiation source,
In addition to X-rays having an X-ray generator as a radiation source, electron beams having an electron beam accelerator as a radiation source are also included.

Among these, in practice, it is preferable to use visible rays, ultraviolet rays, or electron beams, particularly visible rays or ultraviolet rays having a wavelength of 200 to 800 nm.

When ultraviolet rays are used as the light, it is preferable to use the polymerization initiator (C) and, if necessary, an accelerator from the viewpoint of reaction efficiency. It depends on the output of the radiation source, the distance from the radiation source, the irradiation area, the type and amount of the resin, polymerization initiator and accelerator used, the thickness of the resin composition layer, the thickness of the type of tape or sheet substrate, etc. , Normally, the irradiation dose for electron beam is 0.5 to 50 Mrad, and for ultraviolet light is 20 to 5000 mJ
/ cm ² or so, the time of irradiation is about 0.3 to 30 seconds.

Hereinafter, the present invention will be described with reference to examples. In the examples, “parts” means “parts by weight” and “%” means “% by weight”.

Synthesis of polyester oligomer Oligomer 1 Ethylene glycol 2.0 parts Hexahydrophthalic anhydride 51.0 parts Glycidyl methacrylate 47.0 parts N, N-Dimethylbenzylamine 0.9 parts Hydroquinone 0.2 parts Ethyl acetate 25.0 parts Oligomer 2 Ethylene glycol 2.0 parts Hexahydrophthalic anhydride 50.3 parts Glycidyl methacrylate 23.2 parts Phenylglycidyl ether 24.5 parts N, N-dimethylbenzylamine 0.9 parts Hydroquinone 0.1 parts Ethyl acetate 25.0 parts Oligomer 3 p-Hydroxybenzoic acid 4.3 parts Hexahydrophthalic anhydride 48.5 parts Phenylglycidyl ether 47.2 parts N, N-Dimethylbenzylamine 0.9 parts Ethyl acetate 25.0 parts Oligomer 4 Ethylene glycol 2.1 parts Tetrahydrophthalic anhydride 50.6 parts Glycidyl methacrylate 47.3 parts N, N-Dimethylbenzylamine 0.9 parts High Doloquinone 0.2 parts Ethyl acetate 25.0 parts Oligomer 5 Ethylene glycol 2.0 parts Hexahydrophthalic anhydride 49.6 parts Phenylglycidyl ether 48.4 parts N, N-Dimethylbenzylamine 0.9 parts Ethyl acetate 25.0 parts Oligomers 6 Ethylene glycol 2.0 parts Hexahydrophthalic anhydride 50.0 parts Glycidyl Methacrylate 11.5 parts Phenylglycidyl ether 36.5 parts N, N-Dimethylbenzylamine 0.9 parts Hydroquinone 0.1 parts Ethyl acetate 25.0 parts The above compositions are mixed and mixed at 80 ° C in an air atmosphere at 1 ° C.
After reacting for 0 hour and cooling, 125 parts of ethyl acetate was added to obtain 6 kinds of polyester oligomer solutions (solid content 40%).

Synthesis of acrylic polymer Polymer 1 Butyl acrylate 93.5 parts Acrylic acid 1.4 parts 2-Hydroxyethyl methacrylate 5.1 parts Azobisisobutyronitrile 0.2 parts Ethyl acetate 150 parts Polymer 2 Butyl acrylate 92.0 parts Acrylamide 2.8 parts 2-Hydroxyethyl methacrylate 5.2 parts Azo Bisisobutyronitrile 0.2 parts Ethyl acetate 150 parts Polymer 3 Butyl acrylate 88.2 parts Vinyl acetate 5.6 parts 2-Hydroxyethyl methacrylate 6.2 parts Azobisisobutyronitrile 0.2 parts Ethyl acetate 150 parts Each composition above heated to 80 ° C 125 parts of the mixture having the same composition as above was added dropwise to 125 parts of the mixture of
The mixture was heated under reflux for 12 hours and cooled to obtain a solution of three acrylic polymers (solid content 40%).

Example 1 20 parts of a solution of oligomer 1 and 80 parts of a solution of polymer 1 were thoroughly mixed, and 0.4 part of benzoyl peroxide was uniformly mixed with 100 parts of this resin solution, and the mixture was placed on a polyethylene terephthalate film having a thickness of 50 μm. Thickness after drying is 30
It was coated to a thickness of μm, heated at 60 ° C. for 3 minutes to remove the solvent ethyl acetate, and further heated at 130 ° C. for 10 minutes to react the oligomer to obtain an adhesive sheet.

About the obtained adhesive sheet, peel adhesion, tack,
The results of measuring the holding power are shown in the table. The measurement was performed as follows.

(1) Peel adhesion The obtained adhesive sheet was cut into a width of 25 mm and the adhesive surface was # 28.
Stainless steel plate polished with 0 sandpaper (SUS30
After sticking to 4) and leaving it for 30 minutes, the 180 degree peel adhesion was measured at a peeling speed of 300 mm / min under the condition of 25 ° C and relative humidity of 65%.

(2) Tack Set the obtained adhesive sheet on a slope with an inclination angle of 30 degrees, roll a stainless steel ball at a running distance of 10 cm under conditions of 25 ° C and 65% relative humidity, and place it within 10 cm of the adhesive surface. The highest ball number to stop was measured. There are 31 types of ball numbers from 1/16 to 1 "ball designation"
It is displayed with a numerical value 32 times.

(3) Holding power The obtained adhesive sheet was cut into a width of 25 mm and a length of 100 mm, and a 25 mm long and 25 mm wide portion of the adhesive surface was polished with sandpaper # 280 to make a stainless steel plate (SUS304). ), And the time (sec) until the adhesive sheet dropped from the stainless steel plate at 40 ° C and a load of 1 kg was measured.

Example 2 A solution prepared by thoroughly mixing 10 parts of the solution of oligomer 2 and 90 parts of the solution of polymer 2 and further adding 0.4 part of benzoyl peroxide was dried on two sheets of release paper to give a thickness of 30 μm.
m and the mixture was dried at 60 ° C. for 3 minutes, and each was laminated on both sides of a rayon nonwoven fabric having a thickness of 50 μm and impregnated with a resin to obtain a double-sided pressure-sensitive adhesive sheet.

Further, this was heated at 130 ° C. for 10 minutes to react the oligomer, and then a 50 μm polyethylene terephthalate film was attached to one side, and the measurement was carried out in the same manner as in Example 1.

Example 3 85 parts of a solution of oligomer 1; 10 parts of a solution of oligomer 3;
A solution prepared by thoroughly mixing 5 parts of the polymer 3 solution and further adding 0.2 part of 2-hydroxy-2-methylpropiophenone was applied on a polyethylene terephthalate film in the same manner as in Example 1 to obtain an adhesive sheet. . Further, from the adhesive surface side of this adhesive sheet, ultraviolet rays were irradiated for 15 seconds at a distance of 15 cm under a 2 kW high pressure mercury lamp, and then the measurement was carried out in the same manner as in Example 1.

Example 4 A solution prepared by thoroughly mixing 9 parts of the solution of oligomer 4 and 91 parts of the solution of polymer 1 and further adding 0.2 part of 2-hydroxy-2-methylpropiophenone was the same as in Example 3 Was obtained and the measurement was performed.

Example 5 5 parts solution of oligomer 1 5 parts solution of oligomer 5
The adhesive sheet was obtained in the same manner as in Example 3 using a solution prepared by thoroughly mixing 90 parts of the polymer 2 solution and further adding 0.2 parts of 2-hydroxy-2-methylpropiophenone.

Moreover, after obtaining a double-sided pressure-sensitive adhesive sheet in the same manner as in Example 2, 15 cm under a 2 kW high-pressure mercury lamp was placed on both sides of this double-sided pressure-sensitive adhesive sheet.
After irradiating with ultraviolet rays for 15 seconds at a distance of 50 μm, a polyethylene terephthalate film having a thickness of 50 μm was attached to one side to obtain the same adhesive sheet for measurement as in Example 2.

The two types of pressure-sensitive adhesive sheets were measured in the same manner as in Example 1.

Example 6 A solution prepared by thoroughly mixing 10 parts of the solution of oligomer 2 and 90 parts of the solution of polymer 2 and further adding 0.2 part of 2-hydroxy-2-methylpropiophenone was used in the same manner as in Example 5 The adhesive sheet was obtained and the measurement was performed.

Example 7 20 parts of the solution of the oligomer 2 and 80 parts of the solution of the polymer 2 were sufficiently mixed, and 0.2 parts of 2-hydroxy-2-methylpropiophenone was further added. The adhesive sheet was obtained and the measurement was performed.

 The above results are shown in the table.

[Advantages of the Invention] As shown in the table, the pressure-sensitive adhesive sheet produced from the resin composition of the present invention has a peel adhesion of 1200 g / 25 mm or more, a tack of 7 or more, and a holding power after heating or after light irradiation. Is 20000
It is more than a second (6 hours) and has excellent adhesive properties and balance.

Thus, by using the resin composition for pressure-sensitive adhesive of the present invention, by applying or impregnating, heating or light irradiation,
Even without the use of a cross-linking agent such as polyisocyanate, it is possible to obtain an adhesive tape or sheet that has an excellent balance of adhesive strength and cohesive strength and does not require a maturing period.

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Claims (2)

(57) [Claims] 1. A polyester oligomer (A) and a tacky acrylic polymer (B) obtained by using, as a main raw material, an epoxide (b) having an ethylenically unsaturated group as a total amount or a part of a cyclic acid anhydride (a) and an epoxide. A resin composition for a pressure-sensitive adhesive, which comprises a mixture of: 2. The resin composition according to claim 1 is optionally mixed with a polymerization initiator (C), and after coating or impregnating a substrate, the unsaturated group is reacted by heating or light irradiation. An adhesive tape or sheet characterized by being produced by