JP2000096011A - Adhesive sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an adhesive sheet having high tenacity and high adhesiveness to all adherends and excellent in propriety for adhesion to the curved surface. SOLUTION: This adhesive sheet comprises layers of a surface substrate an adhesive layer, and an ablation sheet, the adhesive layer is obtained by following method; an acrylic copolymer at least comprising 0.1-20 wt.% monomer having a carboxyl group and 50-90 wt.% vinyl monomer having a 4-18C alkyl ester as component monomers, a mixture compounded at the ratio of 80 pts.wt. monomer and/or oligomer having radical polymerizable double bond based on 100 pts.wt. acrylic copolymer resin and a tackifier having >=100 deg.C softening point (JIS K2207) and non-polymerizable by ionizing radiation are coated and cured by irradiation with ionizing radiation.

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 sheet using an ionizing radiation-curable pressure-sensitive adhesive composition, and in particular, exhibits a high adhesive strength to all adherends and has excellent suitability for sticking to curved surfaces. Further, the present invention relates to a pressure-sensitive adhesive sheet using a pressure-sensitive adhesive composition having high holding power.

[0002]

2. Description of the Related Art Adhesive sheets are used as labels, seals, stickers, patches, and the like for a very wide range of uses such as commercial use, office use, and home use. The general configuration of such a pressure-sensitive adhesive sheet is a state in which a pressure-sensitive adhesive layer is sandwiched between a surface substrate and a release sheet, and the surface substrate includes paper, cloth / nonwoven fabric, film, metal foil, and the like. Are used as the release sheet, high-density base paper such as glassine paper, clay-coated paper, polyethylene laminated paper,
A material obtained by laminating polyethylene on high-density base paper such as glassine paper, or a material obtained by applying a release agent such as a silicone compound or a fluorine compound to a release substrate such as a film is used. As the pressure-sensitive adhesive, a solvent-type pressure-sensitive adhesive, an emulsion-type pressure-sensitive adhesive, a hot-melt-type pressure-sensitive adhesive, and the like are used, but each has the following disadvantages.

[0003] That is, since the solvent-based adhesive uses a large amount of a highly flammable and toxic solvent, there is a risk of fire and explosion and a problem of hygiene. It takes a long time to dry and the water resistance of the pressure-sensitive adhesive is poor. On the other hand, hot-melt adhesives generally require a weight-average molecular weight of hundreds of thousands to millions of molecular weight in order to exhibit sufficient properties. Since it is difficult to apply at a high speed, the operability of the production of an adhesive sheet is inferior.

[0004]

In order to improve the above-mentioned drawbacks of the pressure-sensitive adhesive, an ionizable material obtained by mixing an acrylic copolymer resin with a monomer and / or oligomer having a radical polymerizable double bond is used. Radiation-curable pressure-sensitive adhesives have been proposed. However, the conventionally proposed ionizing radiation-curable pressure-sensitive adhesive, when cured to such an extent that a sufficient holding force is exhibited, the adhesive force to a nonpolar polymer substance such as polyethylene or polypropylene becomes insufficient. In addition, there is a drawback that the suitability for sticking to a curved surface is poor.

The present invention solves the above-mentioned disadvantages of the ionizing radiation-curable pressure-sensitive adhesive by adding a tackifier resin having a specific softening point to the acrylic copolymer resin, and has a high holding power. It is another object of the present invention to provide a pressure-sensitive adhesive sheet using a pressure-sensitive adhesive composition having a high adhesive strength to any adherend and excellent suitability for sticking to a curved surface.

[0006]

The present invention relates to a pressure-sensitive adhesive sheet comprising a surface substrate, a pressure-sensitive adhesive layer and a release sheet, wherein the pressure-sensitive adhesive layer comprises 0.1 to 20% by weight of a monomer having a carboxyl group. and C _{4 ~ 18} alkyl ester and an acrylic copolymer resin having at least as a constituent monomer 50-90 wt% vinyl monomer having a monomer and / or oligomer the acrylic copolymer having a radically polymerizable double bond A mixture blended at a ratio of 80% by weight or less with respect to 100 parts by weight of a resin, and a tackifier resin having a softening point (JIS K2207) of 100 ° C. or higher and not polymerized by ionizing radiation, The composition is characterized in that it is a layer cured by applying an ionizing radiation after applying a pressure-sensitive adhesive composition containing 1 to 25% by weight to the composition. It is a pressure-sensitive adhesive sheet.

DETAILED DESCRIPTION OF THE INVENTION In the present invention, as a main component of the ionizing radiation-curable adhesive composition, the vinyl monomer 50 having a monomer 0.1 to 20% by weight and C _{4 ~ 18} alkyl esters having a carboxyl group The reason for using a mixture of an acrylic copolymer resin having at least 90% by weight as a constituent monomer and a monomer and / or oligomer having a radical polymerizable double bond is that such an acrylic copolymer resin is a rubber-based resin. This is because they are superior in both weather resistance and adhesive physical properties.

As the monomers constituting the acrylic copolymer resin used in the present invention, monomers substantially the same as the monomers of the resins used in ordinary solvent-type or emulsion-type acrylic pressure-sensitive adhesives can be used. Carboxyl group, alkyl group, hydroxyl group, epoxy group,
Various vinyl monomers having an alkoxyl group, an ethylene oxide group, an amino group, an amide group, a halogen atom, a phosphoric acid group, a sulfonic acid group, a silane group, a urethane group, a phenyl group, a benzyl group, a tetrahydrofurfuryl group, and the like. And copolymerizable monomers.

[0008] Specific examples of such monomers are shown below. (A) Vinyl monomer having a carboxyl group: acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, 2-methacryloyloxysuccinic acid, 2-methacryloyloxyethylmaleic acid, 2-methacryloyloxyethylphthalic acid, 2- Methacryloyloxyethyl hexahydrophthalic acid and the like. (B) a vinyl monomer having a C _{1 ~ 3} alkyl esters: methyl (meth) acrylate, ethyl (meth) acrylate, n- propyl (meth) acrylate, isopropyl (meth) acrylate.

[0009] (C) a vinyl monomer having a C _{4 ~ 18} alkyl esters: n-butyl (meth) acrylate, isobutyl (meth) acrylate, isoamyl (meth) acrylate, n- hexyl (meth) acrylate, cyclohexyl (meth) acrylate , N-octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate and the like.

(D) Vinyl monomer having a hydroxyl group: 2-hydroxyethyl (meth) acrylate, 2
-Hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-chloro-2-
Hydroxypropyl (meth) acrylate and the like. (E) Vinyl monomers having an epoxy group: glycidyl (meth) acrylate, methyl glycidyl (meth) acrylate and the like.

(F) Vinyl monomers having an alkoxyl group: methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, butoxyethyl (meth)
Acrylate, phenoxyethyl (meth) acrylate and the like. (G) Vinyl monomers having an ethylene oxide group: diethylene glycol (meth) acrylate, methoxydiethylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, phenoxydiethylene glycol (meth) acrylate, phenoxypolyethylene glycol (meth) acrylate, and the like.

(H) Vinyl monomer having amino group:
Dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, N-tert-butylaminoethyl (meth) acrylate, methacryloyloxyethyltrimethylammonium chloride (meth)
Acrylate and the like. (I) a vinyl monomer having an amide group: (meth) acrylamide, N-methylol (meth) acrylamide,
N-methoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, N, N'-methylenebis (meth) acrylamide and the like.

(J) Vinyl monomers having a halogen atom: trifluoroethyl (meth) acrylate, pentadecafluorooctyl (meth) acrylate, 2-chloroethyl (meth) acrylate, 2,3-dibromopropyl (meth) acrylate, Tribromophenyl (meth) acrylate and the like. (K) Vinyl monomers having a phosphoric acid group: 2-methacryloyloxyethyl diphenyl phosphate (meth) acrylate, trimethacryloyloxyethyl phosphate, triacryloyloxyethyl phosphate, and the like.

(L) a vinyl monomer having a sulfonic acid group: sodium sulfopropyl (meth) acrylate;
Sodium-2-sulfoethyl (meth) acrylate,
Sodium vinyl sulfonate, sodium styrene sulfonate,
Sodium 2-acrylamido-2-methylpropanesulfonate, sodium 3-allyloxy-2-hydroxypropanesulfonate and the like. (M) Vinyl monomer having a silane group: vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, vinyltriacetylsilane, methacryloyloxypropyltrimethoxysilane and the like.

(N) Vinyl monomer having urethane group: urethane (meth) acrylate and the like. (O) Vinyl monomer having a phenyl group: phenyl (meth) acrylate, p-tert-butylphenyl (meth) acrylate, o-biphenyl (meth) acrylate, and the like.

(P) Vinyl monomer having a benzyl group: benzyl (meth) acrylate and the like. (Q) Vinyl monomer having a tetrahydrofurfuryl group: tetrahydrofurfuryl (meth) acrylate and the like. (R) Other monomers: styrene, chlorostyrene,
α-methylstyrene, vinyltoluene, vinyl chloride, vinyl acetate, vinyl propionate, Veova 10 (vinyl alkylate compound, Shell Chemical), acrylonitrile,
Vinylpyridine and the like.

In the present invention, the acrylic copolymer resin is selected from the above-mentioned various monomers to be substantially the same as the monomer used in the solvent-type or emulsion-type acrylic pressure-sensitive adhesive, and is used as the copolymer resin. but is the, in the present invention, (a) a vinyl monomer having a carboxyl group, (C) C _{4 ~ 18} vinyl monomer and acrylic acid with these monomers copolymerizable with the monomer and the constituent monomers having an alkyl ester An ester copolymer resin is used.

The proportion of the vinyl monomer having a carboxyl group (A) in the acrylate copolymer is 0.1 to 2 in view of the cross-linking property and the stability over time of the adhesive performance.
It is about 0% by weight. The proportion of vinyl monomer having a (C) C _{4 ~ 18} alkyl esters, in consideration of the glass transition temperature of the adhesive is about 50 to 90% by weight of the total monomers. In the present invention, in particular butyl acrylate Among vinyl monomer having a C _{4 ~ 18} alkyl esters, 2-ethylhexyl acrylate are preferably used from the viewpoint of copolymerizability and glass transition temperature. Further, the proportion of other copolymerizable monomers in the acrylate copolymer is desirably adjusted in the range of 10 to 50% by weight of all monomers. In the present invention, among other copolymerizable monomers, particularly, methyl (meth) acrylate, vinyl acetate, glycidyl (meth) acrylate, and the like are preferably used from the viewpoint of glass transition temperature, adhesive performance, and the like.

The acrylic copolymer resin used in the present invention may be obtained by polymerizing the above monomers by any method such as bulk polymerization, solution polymerization, suspension polymerization and emulsion polymerization. In addition, after previously polymerizing an acrylic copolymer having a vinyl monomer having an epoxy group as a constituent monomer, a vinyl monomer having a hydroxyl group, a vinyl monomer having an amino group, or a vinyl monomer having a carboxyl group is added thereto. In addition, an acrylic copolymer resin having an ethylenically unsaturated bond introduced into the acrylic copolymer resin may be used in combination.

The acrylic copolymer resin may be copolymerized with a polyfunctional vinyl monomer within a range that does not impair the applicability of the pressure-sensitive adhesive composition. Specific examples of such polyfunctional vinyl monomers include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, and 1,3-butylene glycol. Di (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylolmethanetetra (meth) acrylate, divinylbenzene, N, N'-methylenebisacrylamide, 1,4-butanediol di (meth) acrylate, 1, 6-hexanediol di (meth) acrylate and the like.

In the present invention, the weight average molecular weight of the acrylic copolymer resin is not particularly limited.
× 10 is less than ⁴ can cause the pressure-sensitive adhesive composition is unexpected obtained having an adhesive force and sufficient holding force even when irradiated with ionizing radiation, also a low viscosity even when heated at a high temperature exceeding 5 × 10 ⁵ 1 × 1 because it is difficult to obtain a pressure-sensitive adhesive composition having good application suitability
0 ^{4 to} 5 × 10 ⁵ , more preferably 1 × 10 ^{5 to} 3 × 10 ⁵
Desirable molecular weights are desirable.

Further, the acrylic copolymer resin of the present invention contains various plasticizers, anti-aging agents, stabilizers, softeners such as oils, fillers, pigments, colorants, etc. in order to improve the physical properties of the resins. Can also be added as appropriate.

In the pressure-sensitive adhesive composition of the present invention, examples of the monomer and oligomer having a radical polymerizable double bond to be mixed with the acrylic copolymer resin include the following.

Examples of the oligomer include (a) aliphatic (alicyclic), alicyclic, araliphatic, and aromatic dihydric to hexavalent polyhydric alcohols or poly (meth) acrylic acid obtained as an ester of (meth) acrylic acid. )
(B) an ester of (meth) acrylic acid with a polyhydric alcohol obtained by adding an alkylene oxide to an aliphatic, alicyclic, araliphatic or aromatic dihydric or hexahydric polyhydric alcohol; (C) poly (meth) acryloyloxyalkyl phosphate ester; (d) polyester poly (meth) acrylate; (e) epoxy poly (meth) acrylate; (f) polyurethane poly (meth) acrylate (G) polyamide poly (meth) acrylate; (h) polysiloxane poly (meth) acrylate; (i) vinyl- or diene-based low polymer having a (meth) acryloyloxy group at a side chain and / or terminal; j) The oligoester (meth) according to (a) to (i) above
Modified acrylate; and the like.

As the monomer, there can be used a monomer represented by the above-mentioned compounds constituting the acrylic copolymer resin, and specifically, (a) ethylenically unsaturated mono- or polycarboxylic acid, etc. And (b) ethylenically unsaturated (meth) acrylamide or alkyl-substituted (meth) acrylamide, N-vinyl, and the like. Amide group-containing monomers represented by vinyl lactams such as pyrrolidone; (c) Sulfonic acid group-containing monomers represented by aliphatic or aromatic vinyl sulfonic acids and their alkali metal salts, ammonium salts, amine salts, etc. Sulfonate-containing monomers; (d) water represented by ethylenically unsaturated ethers, etc. (E) dimethylaminoethyl (meth) acrylate-2
An amino group-containing monomer such as vinylpyridine; (f) a quaternary ammonium base-containing monomer; (g) an alkyl ester of an ethylenically unsaturated carboxylic acid; (h) a nitrile group-containing monomer such as (meth) acrylonitrile; Esters of ethylenically unsaturated alcohols such as vinyl acetate and (meth) allyl acetate; (j) mono (meth) acrylates of alkylene oxide addition polymers of compounds containing active hydrogen; (k) polybasic acids and unsaturated Ester group-containing bifunctional monomers represented by diesters with alcohols; (l) bisacrylamides such as N, N-methylenebisacrylamide; (m) divinylbenzene, divinylethylene glycol, divinylsulfone, divinylether, divinylketone, etc. Bifunctional monomer; (n) a polycarboxylic acid and unsaturated alcohol An ester group-containing monomer represented by an ester; (o) a trifunctional monomer such as a cyanuric acid derivative containing three ethylenically unsaturated bonds; (p) an alkylene oxide addition polymer of a compound containing active hydrogen and (meth) (Q) a polyfunctional unsaturated monomer such as trivinylbenzene; and the like. Of course, the material is not limited to these, and various materials that can be crosslinked by irradiation with ionizing radiation can be used, and two or more types can be used in combination.

In the present invention, the proportion of the monomer and / or oligomer having a radical polymerizable double bond used in combination with the acrylic copolymer resin depends on the type of the resin component and the monomer (or oligomer), and furthermore, the tackifier described later. It can be appropriately selected according to the type of the agent resin, etc., and is not particularly limited, but is preferably 80% by weight or less, and more preferably 1% by weight based on 100 parts by weight of the acrylic copolymer resin.
Monomers and / or oligomers are used together in the range of about 60% by weight.

The invention, acrylic copolymer resin having at least as a constituent monomer 50-90 wt% vinyl monomer having a monomer 0.1 to 20% by weight and C _{4 ~ 18} alkyl esters having carboxyl group such as described above And a pressure-sensitive adhesive composition containing a monomer and / or oligomer having a radical polymerizable double bond as a main component,
The softening point based on SK 2207 is 100 ° C. or higher, and has a significant feature in that a tackifier resin which is not polymerized by ionizing radiation is contained in an amount of 1 to 25% by weight based on the total solid content of the pressure-sensitive adhesive composition. .

Incidentally, when only the tackifier resin having a softening point of less than 100 ° C. is used in the ionizing radiation-curable pressure-sensitive adhesive composition as in the present invention, it has a high holding power and a sufficient non-polar polymer substance. Since a pressure-sensitive adhesive composition having an adhesive force cannot be obtained and the suitability for sticking to a curved surface is deteriorated, a tackifier resin having a softening point of 100 ° C. or more is used as an essential component in the present invention.

Specific examples of such a tackifier resin include:
Rosin or its derivative, modified rosin or its derivative, terpene-based resin, modified terpene or its derivative, petroleum-based resin, cyclopentadiene resin, phenol-based resin, styrene-based resin, xylene-based resin, cumarone-indene resin, vinyltoluene- α-methylstyrene copolymer resin, alkylphenol acetylene resin and the like,
In the present invention, among these various resins, the softening point is 10
Those having a temperature of 0 ° C. or higher are selectively used. In addition,
Two or more of these tackifier resins may be used in combination.
It is also possible to use a tackifier resin having a softening point of less than 100 ° C. in order to improve the compatibility of the tackifier resin. The amount used is desirably 60% by weight or less, preferably 50% by weight or less of the tackifier resin having a softening point of 100 ° C. or higher.

In the present invention, a specific amount of a tackifier resin having a specific softening point is used. However, if the amount is less than 1% by weight, a sufficient effect cannot be obtained. The pressure-sensitive adhesive after curing by irradiation becomes too hard, resulting in low tack (ball rolling method) specified in JIS Z 0237, insufficient adhesion, and inhibition of curing by ionizing radiation irradiation. In this case, the balance of the adhesive properties is lost, which is inconvenient. Therefore, the content is set to 1 to 25% by weight, preferably 2 to 20% by weight.

As described above, the ionizing radiation-curable pressure-sensitive adhesive composition of the present invention comprises a monomer having a carboxyl group.
20 and the acrylic copolymer resin having a weight percent and at least a constituent monomer of 50-90% by weight vinyl monomer having a C _{4 ~ 18} alkyl esters, a monomer and / or oligomer having a radical polymerizable double bond adhesive It is prepared by using an imparting resin as an essential component and further adding various additives as necessary.

Depending on the type of acrylic copolymer resin and monomer (or oligomer) used, the viscosity of the pressure-sensitive adhesive composition may increase with time. In such a case, the monomer and / or oligomer may be added immediately before the application, or the monomer and / or the oligomer may be added to the pre-heated acrylic copolymer resin immediately before the application. An increase in the viscosity of the pressure-sensitive adhesive composition can be prevented.

In the present invention, the phenomenon involving repelling phenomenon
Without forming a pressure-sensitive adhesive layer with a uniform and appropriate thickness.
The viscosity at the time of application of the pressure-sensitive adhesive composition is 5 × 10¹ ~ 2x
10 ^Five cps, more preferably 1 × 10^Two~ 1 × 10^Fivecps
It is desirable to make it within the range. Adhesive composition viscosity
As a method of adjusting the degree within the above range, for example, the viscosity
If lowering, use acrylic copolymer tree
Acrylic copolymer that reduces the weight average molecular weight of fat
Ratio of monomer and / or oligomer to body resin
Methods such as increasing the adhesive rate and heating the pressure-sensitive adhesive composition.
The adhesive composition is heated (hot melt
Method) is preferred.

The method of applying the pressure-sensitive adhesive composition to a release sheet or a surface substrate is not particularly limited, and various devices such as a die coater, a roll coater, a gravure coater, and a blade coater can be used as appropriate, and heating is required. In such a case, a heating device is appropriately attached to various coating devices. Generally, the amount of the pressure-sensitive adhesive composition applied is preferably adjusted in the range of about 3 to 100 g / m ² , and more preferably in the range of about 5 to 70 g / m ² .

In the pressure-sensitive adhesive sheet of the present invention, the release sheet to be used is not particularly limited, and various commercially available release sheets can be used. Specifically, high-grade paper, medium-grade paper, general paper such as kraft paper, and polylaminate paper obtained by laminating polyethylene or polypropylene on those obtained by supercalendering these to improve smoothness are used as a release substrate, and silicon Coated with a release agent such as a compound or a fluorine compound;
A high-density base paper such as glassine paper coated with a release agent; a high-density base paper such as glassine paper laminated with polyethylene or polypropylene and a release agent applied thereto; a release agent applied to clay-coated paper Things; polyethylene, polypropylene, polyester, polyamide,
A film obtained by applying a release agent to a film of polyimide, polyvinyl chloride or the like, alone or in a laminate. Also, as a release sheet, a product obtained by laminating polyethylene or polypropylene on a surface opposite to a surface to which a release agent is applied, or a product obtained by applying a resin such as vinylidene chloride resin or an acrylic resin and performing water resistance or curl prevention treatment is also available. Can be used.

Examples of the surface substrate include fibrous substrates such as medium-grade paper, high-quality paper, coated paper, cast paper, impregnated paper, cloth, and nonwoven fabric, cellophane, polyethylene, polypropylene, polyester, polyamide, polyimide, and polyvinyl chloride. , Polyvinylidene fluoride, cellulose acetate, polycarbonate, and other film substrates, and their vapor depositions, coatings, laminates, and the like, and further, metal foils and the like.

Thus, the pressure-sensitive adhesive sheet of the present invention is prepared by applying a pressure-sensitive adhesive composition to a release sheet or a surface substrate, irradiating the surface to be coated with ionizing radiation to form a pressure-sensitive adhesive. It is formed by bonding to the surface of the agent or applying a pressure-sensitive adhesive composition to a release sheet or a surface substrate, and applying the ionizing radiation after bonding the surface substrate or the release sheet to the application surface.

As ionizing radiation, ultraviolet rays, electron beams,
Although γ-rays and the like can be used, electron beams are particularly preferable in terms of transparency, energy efficiency, and ease of handling. The dose at the time of electron beam irradiation is 0.5 to 20 Mrad, preferably 1 to 20 Mrad.
It is desirable to adjust in the range of -10 Mrad.

[Examples] The present invention will be described more specifically with reference to the following examples, but the present invention is of course not limited thereto. In the examples, the coating amount, the number of copies, the mixing ratio, and the like are all represented by solid contents. Example 1 A monomer composition of 80 parts by weight of 2-ethylhexyl acrylate, 11 parts by weight of methyl methacrylate, 4 parts by weight of vinyl acetate, and 5 parts by weight of acrylic acid, having a weight average molecular weight of 2 × 1
0 ⁵ of the acrylic copolymer resin was polymerized by a solution polymerization method. 1,3,5-Tris (2-acryloxyethyl) is used as a trifunctional monomer having a radical polymerizable double bond with respect to 100 parts by weight of the acrylic copolymer resin.
4 parts by weight of cyanuric acid (manufactured by Toa Gosei Chemical Industry Co., Ltd., trade name “Aronix M-315”) and a rosin ester-based tackifier resin having a softening point of 125 ° C. (Arakawa Chemical Industries, Ltd.)
8.7 parts by weight of the product “Super Ester A-125” (trade name). The solvent was removed from the solution of the ionizing radiation-curable pressure-sensitive adhesive composition thus prepared to obtain an ionizing radiation-curable pressure-sensitive adhesive composition.

This ionizing radiation-curable pressure-sensitive adhesive composition was
The mixture was heated to 50 ° C., and was coated on a commercially available 50 μm polyester film by a hot melt method using a die coater so that the coating amount was 25 g / m ^2.
An electron beam irradiation treatment was performed at an accelerating voltage of KV and an irradiation dose of 4 Mrad, and then a commercially available polyethylene laminate release sheet was bonded to produce an adhesive sheet. The performance of this pressure-sensitive adhesive sheet was as shown in Table 1.

Example 2 Instead of 8.7 parts by weight of a rosin ester resin having a softening point of 125 ° C., a terpene phenol resin having a softening point of 130 ° C. (manufactured by Yasuhara Yushi Kogyo Co., Ltd.) A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1, except that 10 parts by weight of the name “YS Polystar T-130”) was used. The performance of this pressure-sensitive adhesive sheet was as shown in Table 1.

Example 3 As a tackifier resin, instead of 8.7 parts by weight of a rosin ester resin having a softening point of 125 ° C., a petroleum resin having a softening point of 120 ° C. (trade name “Mitsubishi Oil Corporation”) Oligotec
A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1 except that 10 parts by weight of 1400 ") was used. The performance of this adhesive sheet is
As shown in Table 1.

Example 4 Instead of 8.7 parts by weight of a rosin ester-based resin having a softening point of 125 ° C. as a tackifier resin, a rosin ester-based resin having a softening point of 115 ° C. (manufactured by Arakawa Chemical Industry Co., Ltd.) Name "Super Ester A-115") 5 parts by weight and softening point 12
An adhesive sheet was produced in the same manner as in Example 1 except that 5 parts by weight of a petroleum resin (manufactured by Mitsubishi Petroleum Co., Ltd., trade name “Oligotech 1400”) at 0 ° C. was used in combination. The performance of this pressure-sensitive adhesive sheet was as shown in Table 1.

Example 5 Instead of 8.7 parts by weight of a rosin ester resin having a softening point of 125 ° C. as a tackifier resin, a petroleum resin having a softening point of 120 ° C. (trade name “Mitsubishi Oil Corp.”) Oligotec
1400 ") and 5 parts by weight of a rosin ester-based resin having a softening point of 75 ° C (trade name" Super Ester A-75 "manufactured by Arakawa Chemical Industry Co., Ltd.) in the same manner as in Example 1 To produce a pressure-sensitive adhesive sheet. The performance of this pressure-sensitive adhesive sheet was as shown in Table 1.

Example 6 An ionizing radiation-curable pressure-sensitive adhesive composition prepared in the same manner as in Example 1 was heated to 150 ° C., and was coated on a commercially available polyethylene laminate release sheet with a die coater in an amount of 25 g.
/ M ² after being applied by a hot melt method.
A commercially available 50 μm polyester film was adhered to the surface of the pressure-sensitive adhesive composition, and an electron beam irradiation treatment was performed at an acceleration voltage of 185 KV and a dose of 4 Mrad to produce a pressure-sensitive adhesive sheet. The performance of this pressure-sensitive adhesive sheet was as shown in Table 1.

Example 7 A rosin ester resin having a softening point of 115 ° C. (trade name “Super Ester”, manufactured by Arakawa Chemical Industries, Ltd.) was added to an acrylic copolymer resin solution obtained by polymerization in the same manner as in Example 1. A-11
5 ") 5 parts by weight of a petroleum resin having a softening point of 120 ° C (trade name" Oligotech 1400 "manufactured by Mitsubishi Petroleum Co., Ltd.) were added and mixed, and the solvent was removed to remove the copolymer. A resin mixture was obtained. This copolymer resin mixture was heated to 150 ° C., and a trifunctional monomer having a radical polymerizable double bond (“Aronix M-315” manufactured by Toa Gosei Chemical Industry Co., Ltd.) was added to 100 parts by weight of the resin mixture. )) To a weight of 4 parts by weight and mixing with a kneader, applying the solution to a commercially available 50 μm polyester film by a hot melt method using a die coater, and then applying 4 Mrad at an accelerating voltage of 175 KV.
, And then a commercially available polyethylene laminate release sheet was laminated to produce an adhesive sheet. The performance of this pressure-sensitive adhesive sheet was as shown in Table 1.

Example 8 A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1, except that the addition amount of the tackifier resin was 1.5 parts by weight and the electron beam irradiation treatment was performed at an irradiation amount of 3 Mrad. The performance of this pressure-sensitive adhesive sheet was as shown in Table 1.

Example 9 Instead of 8.7 parts by weight of a rosin ester-based resin having a softening point of 125 ° C., a rosin ester-based resin having a softening point of 115 ° C. (manufactured by Arakawa Chemical Industries, Ltd.) Example 1 except that 30 parts by weight of the name “Super Ester A-115” were used and the electron beam irradiation treatment was performed at an irradiation amount of 5 Mrad.
In the same manner as in the above, an adhesive sheet was produced. The performance of this pressure-sensitive adhesive sheet was as shown in Table 1.

Comparative Examples 1 to 3 An ionizing radiation-curable pressure-sensitive adhesive composition was prepared in the same manner as in Example 1 except that no tackifier resin was added.
On a polyester film. 1
An electron beam irradiation treatment was performed at an irradiation voltage of 2 Mrad (Comparative Example 1), 3 Mrad (Comparative Example 2), and 4 Mrad (Comparative Example 3) at an accelerating voltage of 65 KV. Various kinds of adhesive sheets were manufactured. The performance of these pressure-sensitive adhesive sheets was as shown in Table 1.

Comparative Example 4 A rosin ester resin having a softening point of 75 ° C. (trade name, manufactured by Arakawa Chemical Co., Ltd.) was used as a tackifier resin instead of 8.7 parts by weight of a rosin ester resin having a softening point of 125 ° C. "Superester A-75") An adhesive sheet was produced in the same manner as in Example 1 except that 8.7 parts by weight was used. The performance of this pressure-sensitive adhesive sheet was as shown in Table 1.

Comparative Example 5 As a tackifier resin, instead of 8.7 parts by weight of a rosin ester resin having a softening point of 125 ° C., a petroleum resin having a softening point of 95 ° C. (trade name “Mitsubishi Oil Corp.”) Oligotec 13
00 ") An adhesive sheet was produced in the same manner as in Example 1 except that 8.7 parts by weight was used. The performance of this adhesive sheet is
As shown in Table 1.

Comparative Example 6 As a tackifier resin, instead of 8.7 parts by weight of a rosin ester resin having a softening point of 125 ° C., a terpene phenol resin having a softening point of 80 ° C. (manufactured by Yasuhara Yushi Kogyo Co., Ltd.) A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1, except that 8.7 parts by weight was used. The performance of this pressure-sensitive adhesive sheet was as shown in Table 1.

Comparative Example 7 A pressure-sensitive adhesive sheet was produced in the same manner as in Example 8, except that the amount of the tackifier resin was changed to 0.5 part by weight. The performance of this pressure-sensitive adhesive sheet was as shown in Table 1.

Comparative Example 8 A pressure-sensitive adhesive sheet was produced in the same manner as in Example 8, except that the amount of the tackifier resin was changed to 40 parts by weight. The performance of this pressure-sensitive adhesive sheet was as shown in Table 1.

[0055]

[Table 1]

(Note) ^{* 1} SUS: Stainless steel plate ^{* 2} PE: Polyethylene laminated paper ^{* 3} z: Discontinuous peeling (zipping) Adhesion: Measured according to the 180 ° peeling method specified in JIS Z0237. The adhesion to PE was measured using polyethylene laminated paper as an adherend. Holding force: The time required for falling was measured in accordance with JIS Z 0237. Suitability for pasting on a curved surface: A small piece of the pressure-sensitive adhesive sheet was pasted on a polyethylene rod (diameter: 13 mm), and the lifting from both ends was visually judged. ：: No lifting. Δ: Slight lifting occurs, and there is a practical problem. ×: Completely lifted.

[0057]

EFFECTS OF THE INVENTION The ionizing radiation-curable pressure-sensitive adhesive composition of the present invention exhibits excellent adhesion to all adherends, high holding power, and excellent suitability for sticking to a curved surface. The pressure-sensitive adhesive sheet provided by applying the ionizing radiation-curable pressure-sensitive adhesive composition had excellent pressure-sensitive adhesive properties.

Claims (2)

[Claims] 1. A pressure-sensitive adhesive sheet comprising a surface substrate, a pressure-sensitive adhesive layer and a release sheet laminated, wherein the pressure-sensitive adhesive layer comprises 0.1 to 20% by weight of a monomer having a carboxyl group and C ₄
Vinyl monomer having an alkyl ester of _{18 to} 50
Ratio of 80% by weight or less of an acrylic copolymer resin having at least 0% by weight as a constituent monomer and a monomer and / or oligomer having a radical polymerizable double bond to 100 parts by weight of the acrylic copolymer resin. And a softening point (JIS K2207) of 100
C. or higher, and after applying a pressure-sensitive adhesive composition containing a tackifier resin which is not polymerized by ionizing radiation and 1 to 25% by weight based on the total solid content of the mixture component, is cured by irradiation with ionizing radiation. A pressure-sensitive adhesive sheet, which is a stiffened layer. 2. The pressure-sensitive adhesive sheet according to claim 1, wherein the application of the pressure-sensitive adhesive composition is a hot melt method.