JPWO2019124197A1 - Active energy ray-curable release type pressure-sensitive adhesive composition and release type pressure-sensitive adhesive sheet - Google Patents

Abstract

As an active energy ray-curable release type pressure-sensitive adhesive composition having excellent adhesive properties and stain resistance, an acrylic resin (A), a urethane (meth) acrylate-based compound (B), and the above-mentioned urethane (meth) acrylate-based compound (B) A release-type pressure-sensitive adhesive composition containing an ethylenically unsaturated compound (C), a photopolymerizable initiator (D), and a cross-linking agent (E), excluding the above, SP in the solubility parameter of the acrylic resin (A). The value is 9.9 (cal / cm3) 1/2 or more, the urethane (meth) acrylate-based compound (B) has 2 to 20 ethylenically unsaturated groups, and the ethylenically unsaturated compound. (C) has 2 to 10 ethylenically unsaturated groups, and the total content of the urethane (meth) acrylate-based compound (B) and the ethylenically unsaturated compound (C) is the acrylic resin. (A) To provide an active energy ray-curable release type pressure-sensitive adhesive composition having 20 to 100 parts by weight with respect to 100 parts by weight.

Description

INDUSTRIAL APPLICABILITY According to the present invention, the active energy used for the pressure-sensitive adhesive layer of a release-type pressure-sensitive adhesive sheet for temporary surface protection when processing a member to be processed such as a semiconductor wafer, a printed circuit board, a glass processed product, a metal plate, or a plastic plate. It relates to a linear curable release type pressure-sensitive adhesive composition and a release type pressure-sensitive adhesive sheet.

Conventionally, in a processing process such as manufacturing an integrated circuit from a semiconductor wafer or drilling a hole, surface protection for temporarily protecting the surface of the member to be processed is provided for the purpose of preventing stains or damage to the member to be processed. Adhesive sheet is used. In recent years, due to reasons such as miniaturization of processing technology and thinning of the member to be processed, an appropriate adhesive force is required for the member to be processed, while an adhesive sheet for surface protection is required after the role of surface protection is completed. Is required to be peeled off, and when peeling off, it is required to be able to peel off without adhesive residue with a light force. Further, in recent years, an adhesive sheet for surface protection has been used not only in semiconductor wafers but also in processing various members.

Patent Document 1 describes an adhesive sheet for processing a semiconductor wafer, which exhibits excellent adhesive strength to a semiconductor wafer and has stable adhesive physical properties. In the examples of Patent Document 1, 50 parts by weight of 2-ethylhexyl acrylate, 10 parts by weight of butyl acrylate, 37 parts by weight of vinyl acetate, and 2-hydroxyethyl methacrylate are used as the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet for processing semiconductor wafers. Acrylic resin copolymerized with 3 parts by weight, 2 to 4 functional urethane acrylate having a molecular weight of 5,000 or more, and at least one kind of 3 to 6 functional acrylate monomer having a molecular weight of 1,000 or less. The mixed resin composition is disclosed.

Japanese Unexamined Patent Publication No. 10-310748

The resin composition disclosed in Patent Document 1 does not have sufficient adhesive strength before irradiation with ultraviolet rays, and further improvement is required. Further, in the resin composition, the member to be processed tends to be contaminated by the adhesive layer remaining on the member to be processed when the adhesive sheet is peeled off, and further improvement is required.

However, as a result of intensive studies in view of such circumstances, the present inventor has made an acrylic resin having an SP value of a solubility parameter equal to or higher than a specific value, and a urethane (meth) acrylate-based compound having a specific number of ethylenically unsaturated groups. Active energy ray curable containing an ethylenically unsaturated compound, a photopolymerizable initiator, and a cross-linking agent, and having the total amount of the above urethane (meth) acrylate compound and the ethylenically unsaturated compound in a specific range. It has been found that the release-type pressure-sensitive adhesive composition has excellent pressure-sensitive adhesive properties before and after irradiation with active energy rays, and also has excellent stain resistance to the member to be processed.

That is, the present invention comprises an acrylic resin (A), a urethane (meth) acrylate compound (B), an ethylenically unsaturated compound (C) excluding the urethane (meth) acrylate compound (B), and photopolymerizability initiation. A release-type pressure-sensitive adhesive composition containing an agent (D) and a cross-linking agent (E), wherein the SP value in the solubility parameter of the acrylic resin (A) is 9.9 (cal / cm ³ ) ^1/2 or more. The urethane (meth) acrylate compound (B) has 2 to 20 ethylenically unsaturated groups, and the ethylenically unsaturated compound (C) has 2 to 10 ethylenically unsaturated groups. The total content of the urethane (meth) acrylate compound (B) and the ethylenically unsaturated compound (C) having a group is 20 to 100 parts by weight with respect to 100 parts by weight of the acrylic resin (A). The first gist is an active energy ray-curable release type pressure-sensitive adhesive composition which is a part. The second gist is a peelable pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer in which the active energy ray-curable release-type pressure-sensitive adhesive composition of the first gist is crosslinked with a cross-linking agent (E).

The active energy ray-curable release type pressure-sensitive adhesive composition of the present invention is ethylenically unsaturated except for the acrylic resin (A), the urethane (meth) acrylate compound (B), and the urethane (meth) acrylate compound (B). It contains a saturated compound (C) [hereinafter, simply referred to as "ethylenically unsaturated compound (C)"], a photopolymerizable initiator (D) and a cross-linking agent (E), and the solubility parameter of the acrylic resin (A). The SP value in the above is 9.9 (cal / cm ³ ) ^1/2 or more, the urethane (meth) acrylate compound (B) has 2 to 20 ethylenically unsaturated groups, and the above ethylenically. The unsaturated compound (C) has 2 to 10 ethylenically unsaturated groups, and the total content of the urethane (meth) acrylate compound (B) and the ethylenically unsaturated compound (C) is the above. It is 20 to 100 parts by weight with respect to 100 parts by weight of the acrylic resin (A). As a result, the acrylic resin (A), the urethane (meth) acrylate compound (B), and the ethylenically unsaturated compound (C) have excellent compatibility with each other, and thus each of them is used in the active energy ray-curable release type pressure-sensitive adhesive composition. The ingredients are evenly mixed. When the pressure-sensitive adhesive obtained by cross-linking the active energy ray-curable release type pressure-sensitive adhesive composition with the cross-linking agent (E) is used as the pressure-sensitive adhesive layer of the release-type pressure-sensitive adhesive sheet, before and after irradiation with the active energy rays. It has the effect of being excellent in adhesive properties and stain resistance to the member to be processed.

Further, among the present inventions, in particular, when the glass transition temperature of the acrylic resin (A) is −50 to 20 ° C., the adhesive properties when used as the pressure-sensitive adhesive layer are excellent, and the adhesive to the member to be processed is improved. The stain resistance becomes better.

Further, among the present inventions, in particular, the weight content ratio (B: C) of the urethane (meth) acrylate compound (B) and the ethylenically unsaturated compound (C) is 99.9: 0.1 to 0. When it is .1: 99.9, the adhesive property when used as the pressure-sensitive adhesive layer is excellent, and the stain resistance to the member to be processed is more excellent.

In the present invention, the urethane (meth) acrylate compound (B) is particularly a reaction product of the hydroxyl group-containing (meth) acrylate compound (b1) and the polyhydric isocyanate compound (b2). , It becomes excellent due to the adhesive property after irradiation with active energy rays.

Further, among the present inventions, in particular, when the cross-linking agent (E) is an isocyanate-based cross-linking agent, it is excellent in adhesive properties when used as a pressure-sensitive adhesive layer, and has more stain resistance to a member to be processed. It will be excellent.

Hereinafter, embodiments for carrying out the present invention will be specifically described, but the present invention is not limited thereto.
In the present invention, "(meth) acrylic" means acrylic or methacrylic, "(meth) acryloyl" means acryloyl or methacryloyl, and "(meth) acrylate" means acrylate or methacrylate.
The acrylic resin is a resin obtained by polymerizing a polymerization component containing at least one (meth) acrylate-based monomer.
In the present invention, the term "sheet" is not particularly distinguished from "film" and "tape", but is described as a meaning including these.

The active energy ray-curable release type pressure-sensitive adhesive composition of the present invention is usually used as a pressure-sensitive adhesive layer of a release-type pressure-sensitive adhesive sheet, which is premised on peeling after being once bonded to a member to be processed. The peelable pressure-sensitive adhesive sheet is used in a state where the active energy ray-curable peelable pressure-sensitive adhesive composition is coated on a base material sheet, and after being bonded to a member to be processed, it is adhered by irradiating with active energy rays. The agent layer hardens, the adhesive strength decreases, and the agent layer can be easily peeled off from the member to be processed.

The active energy ray-curable release type pressure-sensitive adhesive composition of the present invention comprises an acrylic resin (A), a urethane (meth) acrylate compound (B), an ethylenically unsaturated compound (C), and a photopolymerizable initiator (D). ) And the cross-linking agent (E). Hereinafter, each component will be described.

[Acrylic resin (A)]
Usually, the acrylic resin is a thermoplastic resin obtained by polymerizing a (meth) acrylic acid alkyl ester-based monomer and a copolymerizable monomer.

The acrylic resin (A) used in the present invention is characterized in that the SP value in the solubility parameter is 9.9 (cal / cm ³ ) ^1/2 or more.
In the present invention, the SP value of the acrylic resin (A) is set to a specific value or higher and is close to the SP value of the urethane (meth) acrylate compound (B) and the ethylenically unsaturated compound (C). It has excellent compatibility. Therefore, each component is uniformly mixed in the active energy ray-peelable composition, which has excellent adhesive properties when formed as an adhesive layer, and also has excellent stain resistance to the member to be processed.

The SP value in the solubility parameter of the acrylic resin (A) is 9.9 (cal / cm ³ ) ^1/2 or more. It is preferably 9.95 (cal / cm ³ ) ^1/2 or more, more preferably 9.99 (cal / cm ³ ) ^1/2 or more, and particularly preferably 10 (cal / cm ³ ) ^1/2 or more. The upper limit of the SP value is usually 20 (cal / cm ³ ) ^1/2 , preferably 18 (cal / cm ³ ) ^1/2 , and particularly preferably 15 (cal / cm ³ ) ^{1 /.} It is ² . If the SP value is too low, the compatibility with the urethane (meth) acrylate compound (B) and the ethylenically unsaturated compound (C) becomes low, and the adhesive properties when used as a pressure-sensitive adhesive are lowered. Further, if the SP value is too low, the stain resistance to the member to be processed becomes low, and the effect of the present invention cannot be obtained.

The SP value in the above solubility parameter is determined from the evaporation energy (ΔE), molar volume (ΔV), and molar ratio of the (meth) acrylic acid alkyl ester-based monomer constituting the acrylic resin (A) and the copolymerizable monomer. Specifically, it can be obtained by the following equation (1).

The glass transition temperature (Tg) of the acrylic resin (A) used in the present invention is preferably −50 to 20 ° C., more preferably −40 to 10 ° C., still more preferably -30 to 0 ° C., and particularly preferably. It is -20 to 0 ° C. If the glass transition temperature is too high, the adhesive properties tend to deteriorate, and if it is too low, the workpiece tends to be contaminated more.

The glass transition temperature (Tg) is a value calculated by applying the following Fox formula to the glass transition temperature and the weight fraction when each monomer constituting the acrylic resin (A) is homopolymerized. Is.
Here, the glass transition temperature when the monomer constituting the acrylic resin (A) is homopolymer is usually measured by a differential scanning calorimeter (DSC), and is measured by JIS K 7121-1987 or JIS. It can be measured by a method conforming to K 6240.

The weight average molecular weight of the acrylic resin (A) is usually 10,000 to 2.5 million, preferably 100,000 to 2 million, particularly preferably 150,000 to 1,500,000, and particularly preferably 200,000 to 1,200,000. If the weight average molecular weight is too small, the stain resistance to the member to be processed tends to be low, and if it is too large, the coatability tends to be lowered, and it tends to be disadvantageous in terms of cost.

Further, the dispersity (weight average molecular weight / number average molecular weight) of the acrylic resin (A) is preferably 20 or less, particularly preferably 10 or less, further preferably 7 or less, and particularly preferably 5 or less. preferable. If the degree of dispersion is too high, the stainability on the member to be processed tends to increase. The lower limit of the dispersity is usually 1.1 from the point of view of the manufacturing limit.

The above weight average molecular weight is the weight average molecular weight converted to the standard polystyrene molecular weight, and is shown on a high performance liquid chromatograph (“Waters 2695 (main body)” and “Waters 2414 (detector)” manufactured by Japan Waters), column: Shodex. GPC KF-806L (exclusion limit molecular weight: 2 × 10 ^7, separation range: one hundred to two × 10 ^7, theoretical plate number: 10,000 plates / the filler material: styrene - divinylbenzene copolymer, filler particle size : 10 μm) is measured by using three in series, and the number average molecular weight can also be obtained by the same method.

The acrylic resin (A) having the above-mentioned characteristics is a (meth) acrylic acid alkyl ester-based monomer which is a polymerization component so that the SP value becomes a specific value or more, and the type and content of the copolymerizable monomer. Can be obtained by adjusting and polymerizing.

The (meth) acrylic acid alkyl ester-based monomer preferably has an alkyl group having usually 1 to 20 carbon atoms, preferably 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, and particularly preferably 4 to 8 carbon atoms. If the number of carbon atoms is too large, the peelability tends to decrease, and the material to be processed tends to be contaminated.
Specifically, for example, methyl (meth) acrylate (SPa: 10.560, SPma: 9.933), ethyl (meth) acrylate, n-butyl (meth) acrylate (SPa: 9.769, SPma: 9. 447), isobutyl (meth) acrylate, tert-butyl (meth) acrylate, n-propyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate (SPa: 9.221), n- Aliphatic (meth) acrylic acids such as octyl (meth) acrylate, isooctyl acrylate, isodecyl (meth) acrylate, lauryl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, and isostearyl (meth) acrylate. Alkyl esters; examples include alicyclic (meth) acrylic acid esters such as cyclohexyl (meth) acrylates and isobornyl (meth) acrylates. These may be used alone or in combination of two or more. In the present specification, SPa in parentheses indicates the SP value of acrylate, SPma indicates the SP value of methacrylate, and the unit is (cal / cm ³ ) ^1/2 .
Among the above (meth) acrylic acid alkyl ester-based monomers, methyl (meth) acrylate and n-butyl (meth) acrylate are preferably used in terms of copolymerizability, adhesive properties, ease of handling, and availability of raw materials. Be done.

The content of the acrylic acid alkyl ester-based monomer in the polymerization component is usually preferably 10 to 99% by weight, particularly preferably 20 to 98% by weight, and even more preferably 30 to 95% by weight. If the content is too small, the adhesive strength before irradiation with active energy rays tends to decrease, and if it is too large, the adhesive strength before irradiation with active energy rays tends to be too high.

Examples of the copolymerizable monomer include a hydroxyl group-containing monomer, a carboxy group-containing monomer, and other copolymerizable monomers.

The hydroxyl group-containing monomer is preferably a hydroxyl group-containing acrylate-based monomer. Specifically, for example, 2-hydroxyethyl (meth) acrylate (SPa: 13.470), 4-hydroxybutyl (meth) acrylate, 5 Acrylic acid hydroxyalkyl esters such as −hydroxypentyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, caprolactone-modified monomers such as caprolactone-modified 2-hydroxyethyl (meth) acrylate, diethylene glycol. Oxyalkylene-modified monomers such as (meth) acrylates and polyethylene glycol (meth) acrylates, primary hydroxyl group-containing monomers such as 2-acryloyloxyethyl-2-hydroxyethylphthalic acid; 2-hydroxypropyl (meth) acrylates, 2- Secondary hydroxyl group-containing monomers such as hydroxybutyl (meth) acrylate and 3-chloro-2-hydroxypropyl (meth) acrylate; tertiary hydroxyl group-containing monomers such as 2,2-dimethyl2-hydroxyethyl (meth) acrylate. be able to. These may be used alone or in combination of two or more.
Among the above-mentioned hydroxyl group-containing monomers, the primary hydroxyl group-containing monomer is preferable in that it is excellent in reactivity with the cross-linking agent (E) described later, and in particular, 2-hydroxyethyl (meth) acrylate and 4-hydroxybutyl (meth). Acrylate is preferred.

The content of the hydroxyl group-containing monomer in the polymerization component is usually 0.1 to 40% by weight, preferably 0.2 to 30% by weight, and more preferably 0.5 to 20% by weight. If the content is too large, cross-linking tends to proceed before the drying process, and problems tend to occur in coatability. If the content is too low, the degree of cross-linking tends to decrease and the contamination of the workpiece tends to increase. Tends to be.

Examples of the carboxy group-containing monomer include (meth) acrylic acid (SPa: 14.040), acrylic acid dimer, crotonic acid, maleic acid, maleic anhydride, fumaric acid, citraconic acid, glutaconic acid, itaconic acid, and acrylamide. Examples thereof include N-glycolic acid and crotonic acid. Of these, (meth) acrylic acid is preferably used in terms of copolymerizability. These may be used alone or in combination of two or more.

The content of the carboxy group-containing monomer in the polymerization component is usually 0.01 to 30% by weight, preferably 0.03 to 20% by weight, and more preferably 0.05 to 10% by weight. If the content is too large, the member to be processed tends to be deteriorated, and if it is too small, the pot life at the time of coating tends to be shortened.

The acrylic resin (A) used in the present invention may appropriately contain other copolymerizable monomers in addition to the above-mentioned hydroxyl group-containing monomer and carboxy group-containing monomer as copolymerizable monomers.
Examples of the other copolymerizable monomer include acetoacetyl group-containing monomers such as 2- (acetoacetoxy) ethyl (meth) acrylate and allyl acetoacetate; glycidyl (meth) acrylate, allyl glycidyl (meth) acrylate and the like. Glycidyl group-containing monomer; carboxylic acid vinyl ester monomer such as vinyl acetate, vinyl propionate, vinyl stearate, vinyl benzoate; phenyl (meth) acrylate, benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, phenyldiethylene glycol ( Monomer containing aromatic rings such as meta) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, styrene, α-methylstyrene; biphenyloxy structure-containing (meth) acrylic acid such as biphenyloxyethyl (meth) acrylate Ester-based monomers; ethoxymethyl (meth) acrylamide, n-butoxymethyl (meth) acrylamide, (meth) acryloylmorpholine, dimethyl (meth) acrylamide, diethyl (meth) acrylamide, dimethylaminopropyl acrylamide, (meth) acrylamide N-methylol (Meta) acrylamide-based monomers such as (meth) acrylamide; 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, methoxydiethylene glycol (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) ) Monomer containing an alkoxy group or an oxyalkylene group such as acrylate and polypropylene glycol mono (meth) acrylate; acrylonitrile, methacrylonitrile, vinyl chloride, vinylidene chloride, alkyl vinyl ether, vinyl toluene, vinyl pyridine, vinyl pyrrolidone, dialkyl itaconate. Examples thereof include esters, fumarate dialkyl esters, allyl alcohols, acrylic chlorides, methyl vinyl ketones, allyl trimethyl ammonium chlorides, and dimethyl allyl vinyl ketones. These may be used alone or in combination of two or more.

The content of the other copolymerizable monomer in the polymerization component is usually 40% by weight or less, preferably 30% by weight or less, and more preferably 25% by weight or less. If there are too many other copolymerizable monomers, the adhesive properties tend to deteriorate.

An acrylic resin (A) having an SP value of a specific value or more can be obtained by appropriately selecting and polymerizing the (meth) acrylic acid alkyl ester-based monomer and the polymerizable monomer. However, it is preferable to select each monomer of the acrylic resin (A) so that the side chain does not contain a radically polymerizable group from the viewpoint of stability during polymerization of the acrylic resin.

As the polymerization method for obtaining the acrylic resin (A), a conventionally known method such as solution radical polymerization, suspension polymerization, bulk polymerization, or emulsion polymerization can be appropriately carried out. Of these, solution radical polymerization is preferable because it can safely and stably produce the acrylic resin (A) with an arbitrary monomer composition.

In the above solution radical polymerization, for example, a monomer component such as a (meth) acrylic acid alkyl ester-based monomer, a copolymerizable monomer, and a polymerization initiator are mixed or dropped in an organic solvent, and the mixture is in a reflux state or usually at 50 to 98 ° C. It may be polymerized for about 0.1 to 20 hours.

Examples of the organic solvent used in the polymerization reaction include aromatic hydrocarbons such as toluene and xylene, aliphatic hydrocarbons such as hexane, esters such as ethyl acetate and butyl acetate, n-propyl alcohol and isopropyl alcohol. Examples thereof include aliphatic alcohols such as, acetone, methyl ethyl ketone, methyl isobutyl ketone, and ketones such as cyclohexanone.

Examples of the above-mentioned polymerization initiator include azo-based polymerization initiators such as azobisisobutyronitrile and azobisdimethylvaleronitrile, which are ordinary radical polymerization initiators, benzoyl peroxide, lauroyl peroxide, and di-tert-butyl peroxide. , Peroxide-based polymerization initiators such as cumene hydroperoxide and the like can be mentioned as specific examples.

In this way, the acrylic resin (A) used in the present invention can be obtained.

[Urethane (meth) acrylate compound (B)]
The urethane (meth) acrylate-based compound (B) used in the present invention is a compound having a urethane bond and a (meth) acryloyl group.

The urethane (meth) acrylate compound (B) is a urethane (meth) acrylate compound (B1) which is a reaction product of a hydroxyl group-containing (meth) acrylate compound (b1) and a polyvalent isocyanate compound (b2). It may be a urethane (meth) acrylate compound (B2) which is a reaction product of a hydroxyl group-containing (meth) acrylate compound (b1), a polyhydric isocyanate compound (b2) and a polyol compound (b3). You may. Among them, in the present invention, it is preferable to use the urethane (meth) acrylate compound (B1) in terms of releasability after irradiation with active energy rays.
In the present invention, only one type of urethane (meth) acrylate compound (B) may be used, or two or more types may be used in combination.

The hydroxyl group-containing (meth) acrylate compound (b1) preferably has one hydroxyl group, and is an ethylenically unsaturated group such as glycerindi (meth) acrylate or 2-hydroxy-3-acryloyl-oxypropyl methacrylate. A hydroxylate-containing (meth) acrylate-based compound containing 2 of the above; pentaerythritol tri (meth) acrylate, caprolactone-modified pentaerythritol tri (meth) acrylate, ethylene oxide-modified pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth). Examples thereof include hydroxyl group-containing (meth) acrylate compounds containing three or more ethylenically unsaturated groups such as acrylate, caprolactone-modified dipentaerythritol penta (meth) acrylate, and ethylene oxide-modified dipentaerythritol penta (meth) acrylate. These hydroxyl group-containing (meth) acrylate compounds (b1) can be used alone or in combination of two or more.

Among these, a hydroxyl group-containing (meth) acrylate compound (b1) containing three or more ethylenically unsaturated groups is preferable, and pentaerythritol tri (meth) acrylate and dipenta are preferable in terms of excellent reactivity and versatility. Elythritol penta (meth) acrylate is particularly preferred.

Examples of the polyhydric isocyanate compound (b2) include aromatics such as tolylene diisocyanate, diphenylmethane diisocyanate, polyphenylmethane polyisocyanate, modified diphenylmethane diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, phenylenedi isocyanate, and naphthalene diisocyanate. Polyisocyanate; aliphatic polyisocyanate such as hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, lysine diisocyanate, lysine triisocyanate; alicyclic type such as hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, norbornene diisocyanate Based polyisocyanates; or trimeric or multimer compounds of these polyisocyanates, allophanate type polyisocyanates, bullet type polyisocyanates, aqueous dispersion type polyisocyanates (for example, "Aquanate 100" and "Aqua" manufactured by Nippon Polyurethane Industry Co., Ltd. Nate 110 ”,“ Aquanate 200 ”,“ Aquanate 210 ”, etc.) and the like. These multivalent isocyanate compounds (b2) can be used alone or in combination of two or more.

Among these, aliphatic diisocyanis such as hexamethylene diisocyanis, trimethylhexamethylene diisocyanis, and lysine diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, isophoron diisocyanis, and norbornen are excellent in reactivity and versatility. An alicyclic diisocyanis such as diisocyanate is preferable, and isofolone diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, and hexamethylene diisocyanate are preferable, and isophoron diisocyanate and hexamethylene diisocyanate are more preferable.

The polyol compound (b3) may be a compound containing two or more hydroxyl groups, for example, an aliphatic polyol, an alicyclic polyol, a polyether polyol, a polyester-based polyol, a polycarbonate-based polyol, a polyolefin-based polyol, and the like. Examples thereof include polybutadiene-based polyols, polyisoprene-based polyols, (meth) acrylic-based polyols, and polysiloxane-based polyols.

Examples of the aliphatic polyol include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, trimethylene glycol, dimethylolpropane, neopentyl glycol, 2,2-diethyl-1,3-propanediol, and 2-butyl-. 2-Ethyl-1,3-propanediol, 1,4-tetramethylenediol, 1,3-tetramethylenediol, 2-methyl-1,3-trimethylenediol, 1,5-pentamethylenediol, 1,6 -Hexamethylenediol, 3-methyl-1,5-pentamethylenediol, 2,4-diethyl-1,5-pentamethylenediol, pentaerythritol diacrylate, 1,9-nonanediol, 2-methyl-1,8 -Adioxy alcohols containing two hydroxyl groups such as octanediol, sugar alcohols such as xylitol and sorbitol, aliphatic alcohols containing three or more hydroxyl groups such as glycerin, trimethylolpropane and trimethylolethane. Can be mentioned.

Examples of the alicyclic polyol include cyclohexanediols such as 1,4-cyclohexanediol and cyclohexyldimethanol, hydrogenated bisphenols such as hydrogenated bisphenol A, and tricyclodecanedimethanol.

Examples of the polyether polyol include alkylene structure-containing polyether polyols such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polybutylene glycol, polypentamethylene glycol, and polyhexamethylene glycol, and these polyalkylene glycols. Random or block copolymers and the like can be mentioned.

Examples of the polyester-based polyol include a condensation polymer of a polyhydric alcohol and a polyvalent carboxylic acid; a ring-opening polymer of a cyclic ester (lactone); a polyhydric alcohol, a polyvalent carboxylic acid, and a cyclic ester. Examples thereof include reactants according to.
Examples of the polyhydric alcohol include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, trimethylene glycol, 1,4-tetramethylenediol, 1,3-tetramethylenediol, and 2-methyl-1,3-tri. Methylenediol, 1,5-pentamethylenediol, neopentyl glycol, 1,6-hexamethylenediol, 3-methyl-1,5-pentamethylenediol, 2,4-diethyl-1,5-pentamethylenediol, glycerin , Trimethylol propane, trimethylol ethane, cyclohexanediols (1,4-cyclohexanediol, etc.), bisphenols (bisphenol A, etc.), sugar alcohols (xylitol, sorbitol, etc.) and the like.
Examples of the polyvalent carboxylic acid include aliphatic dicarboxylic acids such as malonic acid, maleic acid, fumaric acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, and dodecandioic acid; 1,4 Alicyclic dicarboxylic acids such as -cyclohexanedicarboxylic acid; aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, 2,6-naphthalenedicarboxylic acid, paraphenylenedicarboxylic acid and trimellitic acid can be mentioned.
Examples of the cyclic ester include propiolactone, β-methyl-δ-valerolactone, ε-caprolactone and the like.
These polyhydric alcohols, polyvalent carboxylic acids and cyclic esters can be used alone or in combination of two or more.

Examples of the polycarbonate-based polyol include a reaction product of a polyhydric alcohol and phosgene; a ring-opening polymer of a cyclic carbonate ester (alkylene carbonate, etc.).
Examples of the polyhydric alcohol include polyhydric alcohols exemplified in the description of the polyester-based polyol, and examples of the alkylene carbonate include ethylene carbonate, trimethylene carbonate, tetramethylene carbonate, hexamethylene carbonate and the like. Be done.
The polycarbonate-based polyol may be a compound having a carbonate bond in the molecule and having a hydroxy group at the end, and may have an ester bond together with the carbonate bond.

Examples of the polyolefin-based polyol include those having a homopolymer or copolymer of ethylene, propylene, butene or the like as a saturated hydrocarbon skeleton and having a hydroxyl group at the molecular terminal thereof.

Examples of the polybutadiene-based polyol include those having a copolymer of butadiene as a hydrocarbon skeleton and having a hydroxyl group at the molecular terminal thereof.
The polybutadiene-based polyol may be a hydrogenated polybutadiene polyol in which all or part of the ethylenically unsaturated groups contained in the structure are hydrogenated.

Examples of the polyisoprene-based polyol include those having a copolymer of isoprene as a hydrocarbon skeleton and having a hydroxyl group at the molecular terminal thereof.
The polyisoprene-based polyol may be a hydrogenated polyisoprene polyol in which all or part of the ethylenically unsaturated groups contained in the structure are hydrogenated.

Examples of the (meth) acrylic acid polyol include those having at least two hydroxy groups in the molecule of the polymer or copolymer of the (meth) acrylic acid ester, and the (meth) acrylic acid ester includes such For example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, (meth) acrylic. Examples thereof include (meth) acrylic acid alkyl esters such as 2-ethylhexyl acid, decyl (meth) acrylic acid, dodecyl (meth) acrylic acid, and octadecyl (meth) acrylic acid.

Examples of the polysiloxane-based polyol include dimethylpolysiloxane polyol and methylphenylpolysiloxane polyol.

The above-mentioned polyol compound (b3) may be used alone or in combination of two or more.

Among these, aliphatic polyols and alicyclic polyols are preferable in terms of cost, and polyester-based polyols, polyether-based polyols, and polycarbonate-based polyols are preferable in terms of versatility.

The weight average molecular weight of the polyol compound (b3) is usually 60 to 10,000, preferably 100 to 8,000, and more preferably 150 to 6,000. If the weight average molecular weight of the polyol compound (b3) is too large, it becomes difficult to uniformly mix the obtained urethane (meth) acrylate compound (B2) and the acrylic resin (A), and the adhesive residue on the member to be processed becomes difficult. Tends to occur easily. Further, if the weight average molecular weight of the polyol compound (b3) is too small, cracks tend to easily occur in the pressure-sensitive adhesive layer after irradiation with active energy rays.

The urethane (meth) acrylate compound (B) can be produced by reacting the above components with a known reaction means.
Usually, in the case of the urethane (meth) acrylate compound (B1), the hydroxyl group-containing (meth) acrylate compound (b1) and the polyhydric isocyanate compound (b2) are combined with the urethane (meth) acrylate compound (B2). In the case of), the polyol compound (b3) can be further charged into the reactor collectively or separately and urethanized by a known reaction means to produce the compound.

Further, in the case of producing a urethane (meth) acrylate compound (B2), the reaction product obtained by reacting the polyol compound (b3) with the polyhydric isocyanate compound (b2) in advance contains a hydroxyl group ( The method of reacting the meta) acrylate compound (b1) is useful in terms of stability of the urethanization reaction and reduction of by-products.

In the above urethanization reaction, the urethane (meth) acrylate compound (B) can be obtained by terminating the reaction when the residual isocyanate group content of the reaction system becomes 0.5% by weight or less.

In the reaction between the hydroxyl group-containing (meth) acrylate compound (b1) and the polyvalent isocyanate compound (b2), it is preferable to use a reaction catalyst for the purpose of promoting the reaction, and the reaction catalyst is, for example, dibutyl. Organic metal compounds such as tin dilaurate, trimethyltin hydroxide, tetra-n-butyltin, metal salts such as zinc octate, tin octene, tin octylate, cobalt naphthenate, bismuth chloride, bismuth chloride, etc. Triethylamine, benzyldiethylamine, 1,4-diazabicyclo [2,2,2] octane, 1,8-diazabicyclo [5,4,0] undecene, N, N, N', N'-tetramethyl-1,3- In addition to amine-based catalysts such as butanediamine and N-ethylmorpholine, bismuth nitrate, bismuth bromide, bismuth iodide, bismuth sulfide, etc., organic bismuth compounds such as dibutyl bismuth dilaurate and dioctyl bismuth dilaurate, and bismuth 2-ethylhexanoate. Salt, bismuth naphthenate, bismuth isodecanic acid, bismuth neodecanoate, bismuth lauric acid, bismuth maleate, bismuth stearate, bismuth oleate, bismuth linoleic acid, bismuth acetate, bismuth bismuth neodeca Bismuth-based catalysts such as organic acid bismuth salts such as noate, bismuth disalicylate salt and bismuth dicalcified acid, zirconium-based catalysts such as inorganic zirconium, organic zirconium and zirconium alone, zinc 2-ethylhexanoate / zirconium tetraacetylacetate. Examples thereof include those using two or more types of catalysts such as nat. In addition, these catalysts can be used alone or in combination of two or more.

Among these catalysts, dibutyltin dilaurate and 1,8-diazabicyclo [5,4,0] undecene are preferable.

In the urethanization reaction, an organic solvent having no functional group that reacts with an isocyanate group, for example, esters such as ethyl acetate and butyl acetate, ketones such as methyl ethyl ketone and methyl isobutyl ketone, and aromatics such as toluene and xylene. Organic solvents such as tribes can be used.

The reaction temperature is usually 30 to 90 ° C., preferably 40 to 80 ° C., and the reaction time is usually 2 to 10 hours, preferably 3 to 8 hours.

The urethane (meth) acrylate compound (B) thus obtained is required to have 2 to 20 ethylenically unsaturated groups from the viewpoint of releasability after irradiation with active energy rays. The number is preferably 2 to 18, more preferably 4 to 15.
If the number of such ethylenically unsaturated groups is too large, the crosslink density after irradiation with active energy rays becomes too large, and cracks are likely to occur in the pressure-sensitive adhesive layer. If the number is too small, a sufficient crosslink density cannot be obtained. It becomes difficult to peel off after line irradiation.

The weight average molecular weight of the urethane (meth) acrylate compound (B) is usually 500 to 10,000, preferably 750 to 8,000, and more preferably 1,000 to 6,000. If the weight average molecular weight is too high, the viscosity of the urethane (meth) acrylate compound (B) becomes high, the compatibility with the acrylic resin (A) decreases, and the pressure-sensitive adhesive layer on the member to be processed is partially formed. Residue (glue residue) tends to occur easily. If the weight average molecular weight is too low, the urethane (meth) acrylate compound (B) tends to bleed from the pressure-sensitive adhesive sheet, and adhesive residue tends to occur.

The above weight average molecular weight is the weight average molecular weight converted to the standard polystyrene molecular weight, and is displayed on a high performance liquid chromatograph (“ACQUITY APC system” manufactured by Waters), column: ACQUITY APC XT 450 × 1, ACQUITY APC XT. It is measured by using four 200 × 1 and ACQUITY APC XT 45 × 2 in series.

The SP value in the solubility parameter of the urethane (meth) acrylate compound (B) is usually 9 to 15 (cal / cm ³ ) ^1/2 , preferably 9.5 to 13 (cal / cm ³ ) ^1/2 . Particularly preferably, it is 10 to 12 (cal / cm ³ ) ^1/2 . When the SP value is out of the above range, the compatibility with the acrylic resin (A) and the ethylenically unsaturated compound (C) is lowered, and the adhesive properties when used as the pressure-sensitive adhesive layer tend to be lowered. .. The SP value of the urethane (meth) acrylate compound (B) can be calculated from the molecular structure by a method using Fedors.

The absolute value (| (A)-(B) |) of the difference in SP value between the acrylic resin (A) and the urethane (meth) acrylate compound (B) is usually 3 or less, preferably 2 or less. , More preferably 1 or less, and particularly preferably 0.8 or less. When the absolute value of the difference in SP values is out of the above range, the compatibility with the acrylic resin (A) tends to decrease, and the adhesive properties when used as the pressure-sensitive adhesive layer tend to decrease.

The viscosity of the urethane (meth) acrylate-based compound (B) used in the present invention at 60 ° C. is preferably 500 to 100,000 mPa · s, and particularly preferably 1,000 to 50,000 mPa · s. If the viscosity is outside the above range, the coatability tends to decrease. The viscosity can be measured with an E-type viscometer.

In the present invention, the content of the urethane (meth) acrylate compound (B) is usually 5 to 100 parts by weight, preferably 10 to 80 parts by weight, particularly preferably 10 to 80 parts by weight, based on 100 parts by weight of the acrylic resin (A). Is 20 to 60 parts by weight. If the content of the urethane (meth) acrylate compound (B) is too small, it tends to be difficult to peel off after irradiation with the active energy ray, and if the content of the urethane (meth) acrylate compound (B) is too large, the active energy ray tends to be released. After irradiation, the adhesive layer tends to be cracked easily.

[Ethylene unsaturated compound (C)]
The ethylenically unsaturated compound (C) used in the present invention is preferably a (meth) acrylate-based compound, but can be used without particular limitation as long as it is a compound having an ethylenically unsaturated group. The ethylenically unsaturated compound (C) used in the present invention excludes the urethane (meth) acrylate compound (B).

The ethylenically unsaturated compound (C) is required to have 2 to 10 ethylenically unsaturated groups in that it is excellent in peeling characteristics after irradiation with active energy rays. The number is preferably 3 to 9, particularly preferably 4 to 8. If the number of such ethylenically unsaturated groups is too large, the crosslink density after irradiation with active energy rays becomes too large, and cracks are likely to occur in the pressure-sensitive adhesive layer. If the number is too small, a sufficient crosslink density cannot be obtained. It becomes difficult to peel off after line irradiation.

The SP value in the solubility parameter of the ethylenically unsaturated compound (C) is usually 8 to 12 (cal / cm ³ ) ^1/2 , preferably 9 to 11.5 (cal / cm ³ ) ^1/2 , particularly preferably. Is 9.5 to 11 (cal / cm ³ ) ^1/2 . When the SP value is out of the above range, the compatibility with the acrylic resin (A) and the urethane (meth) acrylate compound (B) tends to decrease, and the adhesive properties when used as an adhesive tend to decrease. is there. The SP value of the ethylenically unsaturated compound (C) can be calculated from the molecular structure by a method using Ethylene.

Further, the absolute value (| (A)-(C) |) of the difference in SP value between the acrylic resin (A) and the ethylenically unsaturated compound (C) is usually 3 or less, preferably 1 or less, and further. It is preferably 0.7 or less, and particularly preferably 0.5 or less. When the absolute value of the difference in SP values is out of the above range, the compatibility with the acrylic resin (A) tends to decrease, and the adhesive properties when used as the pressure-sensitive adhesive layer tend to decrease.

Examples of the ethylenically unsaturated compound (C) include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, and propylene glycol di (). Meta) acrylate, dipropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, butylene glycol di (meth) acrylate, neopentythritol glycol di (meth) acrylate, ethylene oxide-modified bisphenol A type di (meth) acrylate, Propropylene oxide-modified bisphenol A-type di (meth) acrylate, cyclohexanedimethanol di (meth) acrylate, ethoxylated cyclohexanedimethanol di (meth) acrylate, dimethyloldicyclopentanedi (meth) acrylate, tricyclodecanedimethanoldi ( Meta) acrylate, 1,6-hexanediol di (meth) acrylate, glycerin di (meth) acrylate, pentaerythritol di (meth) acrylate, ethylene glycol diglycidyl ether di (meth) acrylate, diethylene glycol diglycidyl ether di (meth) Compounds having two ethylenically unsaturated groups such as acrylate, phthalic acid diglycidyl ester di (meth) acrylate, hydroxypentaerythritol-modified neopentythritol di (meth) acrylate, and isocyanuric acid ethylene oxide-modified diacrylate; (Meta) acrylate, pentaerythritol tri (meth) acrylate, tri (meth) acryloyloxyethoxytrimethylol propane, isocyanurate ethylene oxide-modified triacrylate, caprolactone-modified pentaerythritol tri (meth) acrylate, ethylene oxide-modified pentaerythritol tri (meth) ) Compounds having three ethylenically unsaturated groups such as acrylate and glycerin triacrylate ethoxylated; pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, glycerin polyglycidyl Etherpoly (meth) acrylate, caprolactone-modified dipentaerythritol Penta (meth) acrylate, caprolactone-modified dipentaerythritol Hexa (meth) acrylate, caprolactone-modified pentaerythritol tetra (meth) acrylate, ethylene oxide-modified dipentaerythritol penta (meth) acrylate, ethylene oxide-modified dipentaerythritol hexa (meth) acrylate, ethylene oxide-modified pentaerythritol tetra (meth) acrylate Examples thereof include compounds having 4 or more ethylenically unsaturated groups such as.

Further, as the ethylenically unsaturated compound (C), a Michael adduct of (meth) acrylic acid or a 2- (meth) acryloyloxyethyl dicarboxylic acid monoester can also be used in combination, and such a Michael addition of (meth) acrylic acid can be used in combination. Examples of the substance include (meth) acrylic acid dimer, (meth) acrylic acid trimmer, (meth) acrylic acid tetramer and the like.
The 2- (meth) acryloyloxyethyl dicarboxylic acid monoester is a carboxylic acid having a specific substituent, for example, 2- (meth) acryloyloxyethyl succinic acid monoester, 2- (meth) acryloyloxyethyl phthalic acid. Examples thereof include monoesters and 2- (meth) acryloyloxyethyl hexahydrophthalic acid monoesters. Further, other oligoester acrylates can also be mentioned.

The above ethylenically unsaturated compound (C) may be used alone or in combination of two or more.

Among these, an ethylenically unsaturated compound having no hydroxyl group is preferable because it has excellent adhesive properties after irradiation with active energy rays, and more preferably, pentaerythritol tetra (meth) acrylate and dipentaerythritol hexa (meth). Acrylate, caprolactone-modified pentaerythritol tetra (meth) acrylate, ethylene oxide-modified dipentaerythritol hexa (meth) acrylate, ethylene oxide-modified pentaerythritol tetra (meth) acrylate, and particularly preferably pentaerythritol tetra (meth) acrylate, di. It is pentaerythritol hexa (meth) acrylate.

Further, in the present invention, the skeleton of the compound obtained by removing (meth) acrylic acid from the ethylenically unsaturated compound (C) and the hydroxyl group-containing (meth) acrylate compound of the urethane (meth) acrylate compound (B) ( It is preferable that the skeletons of the compounds obtained by removing (meth) acrylic acid from b1) are the same as each other in terms of excellent compatibility and adhesive properties.

The content of the ethylenically unsaturated compound (C) is usually 5 to 100 parts by weight, preferably 10 to 80 parts by weight, particularly preferably 20 to 60 parts by weight, based on 100 parts by weight of the acrylic resin (A). It is a part by weight. If the content of the ethylenically unsaturated compound (C) is too small, it tends to be difficult to peel off after irradiation with active energy rays, and if it is too high, the stain resistance to the member to be processed after peeling tends to decrease.

In the present invention, the total content of the urethane (meth) acrylate compound (B) and the ethylenically unsaturated compound (C) is set to acrylic from the viewpoint of excellent adhesive strength before irradiation with active energy rays and peelability after irradiation. It is important that the amount is 20 to 100 parts by weight with respect to 100 parts by weight of the based resin (A). It is preferably 25 to 90 parts by weight, particularly preferably 30 to 80 parts by weight. If the total content is too small, the adhesive strength is less likely to decrease even when irradiated with active energy rays, and if the total content is too large, the stain resistance to the member to be processed becomes low after irradiation with active energy rays.

Further, the weight content ratio [(B): (C)] of the urethane (meth) acrylate compound (B) and the ethylenically unsaturated compound (C) is preferably 99.9: 0.1 to 0.1. : 99.9, more preferably 99: 1 to 1:99, still more preferably 90:10 to 10:90, and particularly preferably 80:20 to 20:80. If the weight content ratio of the urethane (meth) acrylate compound (B) and the ethylenically unsaturated compound (C) is out of the above range, the adhesive properties of the adhesive layer tend to deteriorate.

[Photopolymerizable initiator (D)]
The photopolymerizable initiator (D) used in the present invention may be any as long as it generates a radical by the action of light, for example, diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one. , Benzoyldimethylketal, 4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone, 1-hydroxycyclohexylphenylketone, 1- [4- (2-hydroxyethoxy) -phenyl] -2- Hydroxy-2-methyl-1-propane-1-one, 2-methyl-2-morpholino (4-thiomethylphenyl) propan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) ) Butanone, acetophenones such as 2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl] propanone oligomer; benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, etc. Benzoyls; benzophenone, methyl o-benzoyl benzoate, 4-phenylbenzophenone, 4-benzoyl-4'-methyl-diphenylsulfide, 3,3', 4,4'-tetra (tert-butylperoxycarbonyl) benzophenone , 2,4,6-trimethylbenzophenone, 4-benzoyl-N, N-dimethyl-N- [2- (1-oxo-2-propenyloxy) ethyl] benzenemethaminium bromide, (4-benzoylbenzyl) trimethyl Benzoyls such as ammonium chloride; 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, 1-chloro-4-propoxythioxanthone, 2- (3-dimethylamino-2-) Hydroxy) -3,4-dimethyl-9H-thioxanthone-9-onemethochloride and other thioxanthones; 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4 , 4-trimethyl-pentylphosphine oxide, acylphosphon oxides such as bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide and the like. Of these, acetophenones are preferable, and 1-hydroxycyclohexylphenyl ketone is particularly preferable. These photopolymerizable initiators (D) can be used alone or in combination of two or more.

In addition, as an auxiliary agent for these photopolymerizable initiators (D), for example, triethanolamine, triisopropanolamine, 4,4'-dimethylaminobenzophenone (Michler ketone), 4,4'-diethylaminobenzophenone, 2-dimethylamino Ethyl benzoic acid, ethyl 4-dimethylaminobenzoate, 4-dimethylaminobenzoic acid (n-butoxy) ethyl, 4-dimethylaminobenzoate isoamyl, 4-dimethylaminobenzoate 2-ethylhexyl, 2,4-diethylthioxane It is also possible to use Son, 2,4-diisopropylthioxanson and the like in combination. These auxiliaries can also be used alone or in combination of two or more.

The content of the photopolymerizable initiator (D) is 0. With respect to a total of 100 parts by weight of the acrylic resin (A), the urethane (meth) acrylate compound (B) and the ethylenically unsaturated compound (C). It is preferably 1 to 20 parts by weight, particularly preferably 0.5 to 15 parts by weight, and particularly preferably 1 to 10 parts by weight. If the content of the photopolymerizable initiator (D) is too small, the peelability after irradiation with active energy rays tends to decrease, and if it is too large, the stain resistance to the member to be processed becomes low after irradiation with active energy rays. Tend.

[Crosslinking agent (E)]
Examples of the cross-linking agent (E) include isocyanate-based cross-linking agents, epoxy-based cross-linking agents, aziridine-based cross-linking agents, oxazoline-based cross-linking agents, melamine-based cross-linking agents, aldehyde-based cross-linking agents, and amine-based cross-linking agents. Among these, it is preferable to use an isocyanate-based cross-linking agent from the viewpoint of improving the adhesiveness of the peelable pressure-sensitive adhesive sheet to the base sheet and the reactivity with the acrylic resin (A).
Further, these cross-linking agents (E) may be used alone or in combination of two or more.

Examples of the isocyanate-based cross-linking agent include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylene diisocyanate, hexamethylene diisocyanate, diphenylmethane-4,4-diisocyanate, and the like. Isophorone diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, tetramethylxylylene diisocyanate, 1,5-naphthalenediocyanate, triphenylmethane triisocyanate, and these polyisocyanate compounds and polyol compounds such as trimethylolpropane. Examples thereof include an adduct body, a bullet body of these polyisocyanate compounds, and an isocyanurate body.
Among these, isocyanurates of hexamethylene diisocyanate, 2,4-tolylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate and trimethylol in terms of drug resistance and reactivity with functional groups. Adducts with propane, isocyanurates of 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate, and adducts of tetramethylxylylene diisocyanate and trimethyl propane are preferred.

Examples of the epoxy-based cross-linking agent include bisphenol A / epichlorohydrin type epoxy resin, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether, and 1,6-hexanediol diglycidyl ether. , Trimethylol Propane triglycidyl ether, sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl erythritol, diglycerol polyglycidyl ether, 1,3'-bis (N, N-diglycidyl aminomethyl) cyclohexane, N , N, N', N'-tetraglycidyl-m-xylene diamine and the like.

Examples of the aziridine-based cross-linking agent include tetramethylolmethane-tri-β-aziridinyl propionate, trimethylolpropane-tri-β-aziridinyl propionate, and N, N'-diphenylmethane-4,4. ′ -Bis (1-aziridine carboxylamide), N, N'-hexamethylene-1,6-bis (1-aziridine carboxylamide) and the like can be mentioned.

Examples of the oxazoline-based cross-linking agent include 2,2'-bis (2-oxazoline), 1,2-bis (2-oxazoline-2-yl) ethane, and 1,4-bis (2-oxazoline-2-yl). Il) butane, 1,8-bis (2-oxazoline-2-yl) butane, 1,4-bis (2-oxazoline-2-yl) cyclohexane, 1,2-bis (2-oxazoline-2-yl) Bisoxazoline compounds containing aliphatic or aromatics such as benzene, 1,3-bis (2-oxazoline-2-yl) benzene, 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, Addition polymerization of 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-ethyl-2-oxazoline, etc. Examples thereof include one or more polymers of sex oxazoline.

Examples of the melamine-based cross-linking agent include hexamethoxymethylmelamine, hexaethoxymethylmelamine, hexapropoxymethylmelamine, hexaptoxymethylmelamine, hexapentyloxymethylmelamine, hexahexyloxymethylmelamine, and melamine resin. ..

Examples of the aldehyde-based cross-linking agent include glyoxal, malondialdehyde, succindialdehyde, maleindialdehyde, glutardaldehyde, formaldehyde, acetaldehyde, and benzaldehyde.

Examples of the amine-based cross-linking agent include hexamethylenediamine, triethyldiamine, polyethyleneimine, hexamethylenetetraamine, diethylenetriamine, triethyltetraamine, isophoronediamine, amino resin, and polyamide.

The content of the cross-linking agent (E) is usually 0, based on 100 parts by weight of the total of the acrylic resin (A), the urethane (meth) acrylate compound (B) and the ethylenically unsaturated compound (C). It is preferably 1 to 30 parts by weight, particularly preferably 0.2 to 20 parts by weight, and even more preferably 0.3 to 15 parts by weight. If the amount of the cross-linking agent (E) is too small, the cohesive force of the pressure-sensitive adhesive is reduced and tends to cause adhesive residue. If the amount of the cross-linking agent (E) is too large, the flexibility and adhesive strength are reduced, and the work is processed. There is a tendency for floating to occur between the members.

[Other ingredients]
The active energy ray-curable release type pressure-sensitive adhesive composition of the present invention comprises, for example, a small amount of monofunctional monomer, antistatic agent, antioxidant, plasticizer, filler, pigment, as long as the effect of the present invention is not impaired. Additives such as a diluent, an antistatic agent, an ultraviolet absorber, and an ultraviolet stabilizer may be further contained, and one of these additives may be used alone or in combination of two or more. In particular, antioxidants are effective in maintaining the stability of the pressure-sensitive adhesive layer. The content of the antioxidant when blended is not particularly limited, but is preferably 0.01 to 5% by weight based on the active energy ray-curable release type pressure-sensitive adhesive composition.
In addition to the above additives, the active energy ray-curable release type pressure-sensitive adhesive composition of the present invention includes impurities and the like contained in the raw materials for producing the constituents of the active energy ray-curable release type pressure-sensitive adhesive composition. May be contained in a small amount.

Further, the active energy ray-curable release type pressure-sensitive adhesive composition of the present invention has low stain resistance to the member to be processed after irradiation with active energy rays, and therefore is terpene-based resin, rosin-based resin, chromane-based resin, and phenol-based resin. It is preferable that it does not contain a tackifier resin such as a resin, a styrene resin, or a petroleum resin.

Thus, an acrylic resin (A), a urethane (meth) acrylate compound (B), an ethylenically unsaturated compound (C), a photopolymerizable initiator (D) and a cross-linking agent (E), and if necessary, other By mixing the components, the active energy ray-curable release type pressure-sensitive adhesive composition of the present invention can be obtained.

The active energy ray-curable release type pressure-sensitive adhesive composition of the present invention is crosslinked by the above-mentioned cross-linking agent (E) and is suitably used as a pressure-sensitive adhesive layer of a release-type pressure-sensitive adhesive sheet. Then, this peelable pressure-sensitive adhesive sheet is bonded to the member to be processed and then irradiated with active energy rays to polymerize the urethane (meth) acrylate compound (B) and the ethylenically unsaturated compound (C) to adhere. The agent layer hardens and the adhesive strength decreases, thereby exhibiting peelability. Utilizing this characteristic, when processing various members to be processed, it is used for temporarily protecting the surface of the member to be processed.
Hereinafter, the peelable adhesive sheet will be described.

Examples of the member to be processed protected by the peelable adhesive sheet include semiconductor wafers, printed circuit boards, glass processed products, metal plates, plastic plates and the like.

The peelable pressure-sensitive adhesive sheet usually has a base material sheet, a pressure-sensitive adhesive layer made of the active energy ray-curable peel-type pressure-sensitive adhesive composition of the present invention, and a release film. As a method for producing such a release-type pressure-sensitive adhesive sheet, first, the active energy ray-curable release-type pressure-sensitive adhesive composition of the present invention is used as it is, or the concentration is adjusted with an appropriate organic solvent, and the composition is directly applied on a release film or a base sheet. Paint. Then, for example, it is dried by heat treatment at 80 to 105 ° C. for 0.5 to 10 minutes, and this is attached to a base sheet or a release film to obtain a release type adhesive sheet. Further, in order to balance the adhesive properties, further aging may be performed after drying.

Examples of the base material sheet include polyester resins such as polyethylene naphthalate, polyethylene terephthalate, polybutylene terephthalate, and polyethylene terephthalate / isophthalate copolymer; polyolefin resins such as polyethylene, polypropylene, and polymethylpentene; and polyvinyl fluoride. , Polyfluorinated ethylene resin such as polyvinylidene fluoride, polyethylene fluoride; polyamide such as nylon 6, nylon 6,6; polyvinyl chloride, polyvinyl chloride / vinyl acetate copolymer, ethylene-vinyl acetate copolymer, ethylene- Vinyl alcohol copolymers, vinyl polymers such as polyvinyl alcohol and vinylon; cellulose resins such as cellulose triacetate and cellophane; acrylic resins such as methyl polymethacrylate, ethyl polymethacrylate, ethyl polyacrylate and butyl polyacrylate. Resin; Polystyrene; Polycarbonate; Polyallylate; Sheet made of at least one synthetic resin selected from the group consisting of polyimide and the like; Aluminum, copper, iron metal foil, high-quality paper, glassin paper and other paper, glass fiber, natural fiber , Textiles and non-woven fabrics made of synthetic fibers and the like. These base material sheets can be used as a single layer or as a multi-layer in which two or more kinds are laminated. Among these, a sheet made of synthetic resin is preferable from the viewpoint of weight reduction and the like.

Further, as the release film, for example, various synthetic resin sheets, papers, woven fabrics, non-woven fabrics and the like exemplified in the base sheet can be used after being released.

The coating method of the active energy ray-curable release type pressure-sensitive adhesive composition is not particularly limited as long as it is a general coating method, and for example, roll coating, die coating, gravure coating, and comma coating. , Screen printing and the like.

The thickness of the pressure-sensitive adhesive layer in the peelable pressure-sensitive adhesive sheet is usually preferably 1 to 200 μm, more preferably 10 to 100 μm.

As the active energy rays, light rays such as far ultraviolet rays, ultraviolet rays, near ultraviolet rays and infrared rays, electromagnetic waves such as X-rays and γ rays, as well as electron beams, proton rays and neutron rays can be used, but the curing rate and irradiation It is advantageous to use ultraviolet rays because of the availability of the device and the price.

Total irradiation amount of the ultraviolet radiation is typically 50~3,000mJ / cm ^2, preferably 100~1,000mJ / cm ^2. The irradiation time varies depending on the type of light source, the distance between the light source and the pressure-sensitive adhesive layer, the thickness of the pressure-sensitive adhesive layer, and other conditions, but is usually several seconds, and in some cases even a very short time of less than one second. Good.

The adhesive strength of the peelable adhesive sheet varies depending on the type of the base material sheet, the type of the member to be processed, etc., but is preferably 1 to 30 N / 25 mm, more preferably 1 to 20 N / 25 mm before irradiation with active energy rays. preferable. The adhesive strength after irradiation with active energy rays is preferably 0.01 to 1 N / 25 mm, more preferably 0.05 to 0.5 N / 25 mm.
The adhesive force after irradiation with the active energy ray is preferably 1/5 or less, more preferably 1/50 or less of the adhesive force before the irradiation with the active energy ray.

The peelable pressure-sensitive adhesive sheet using the active energy ray-curable peel-type pressure-sensitive adhesive composition of the present invention as a pressure-sensitive adhesive layer is formed by bonding it to a member to be processed to temporarily protect the surface of the member to be processed. By irradiating with active energy rays, the adhesive layer is hardened and the adhesive strength is reduced, so that the adhesive layer can be easily peeled off from the member to be processed.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples as long as the gist of the present invention is not exceeded. The terms "%" and "part" below mean the weight standard.

Each component contained in the active energy ray-curable release type pressure-sensitive adhesive composition of Examples and Comparative Examples is as follows.
The composition of the acrylic resin is shown in Table 1 below.

-N-Butyl acrylate [SP value: 9.769 (cal / cm ³ ) ^1/2 , molecular weight: 128.2]
2-Ethylhexyl acrylate [SP value: 9.221 (cal / cm ³ ) ^1/2 , molecular weight: 184.3]
-Methyl acrylate [SP value: 10.560 (cal / cm ³ ) ^1/2 , molecular weight: 86.1]
-Methyl methacrylate [SP value: 9.933 (cal / cm ³ ) ^1/2 , molecular weight: 100.1]
2-Hydroxyethyl acrylate [SP value: 14.480 (cal / cm ³ ) ^1/2 , molecular weight: 116.1]
2-Hydroxyethyl methacrylate [SP value: 13.470 (cal / cm ³ ) ^1/2 , molecular weight: 144.2]
-Acrylic acid [SP value: 14.040 (cal / cm ³ ) ^1/2 , molecular weight: 72.1]

<Acrylic resin>
[Acrylic resin (A-1)]
29 parts of ethyl acetate was placed in a reactor equipped with a temperature controller, thermometer, stirrer, dropping funnel and reflux condenser, and the temperature was raised while stirring. When the internal temperature became stable at 78 ° C, n- A mixture obtained by mixing and dissolving 91.9 parts of butyl acrylate, 0.1 part of 2-hydroxyethyl methacrylate, 8 parts of acrylic acid, and 0.037 parts of azobisisobutyronitrile (AIBN) was added dropwise over 2 hours and refluxed. Reacted with. Then, 3.5 hours after the start of the reaction (after reflux), a solution in which 1.5 parts of ethyl acetate and 0.025 parts of AIBN were dissolved was added. Further, 5.5 hours after the start of the reaction, a solution prepared by dissolving 4 parts of toluene and 0.05 part of AIBN was added. 7.5 hours after the start of the reaction, 57.5 parts of ethyl acetate and 100 parts of toluene were added to terminate the reaction, and the solution-like acrylic resin (A-1) [SP value: 100.57 (cal / cm ³ )). ^1/2 , weight average molecular weight: 800,000, glass transition temperature (Tg): −48.2 ° C., resin content: 35.0%, viscosity: 8,000 mPa · s (25 ° C.)] was obtained.

[Acrylic resin (A-2)]
In the acrylic resin (A-1), in the same manner except that the polymerization component was changed to 70 parts of n-butyl acrylate and 30 parts of 2-hydroxyethyl acrylate, the solution acrylic resin (A-2) [SP Value: 11.065 (cal / cm ³ ) ^1/2 , weight average molecular weight: 700,000, glass transition temperature: -45.1 ° C, resin content: 35.0%, viscosity: 6,000 mPa · s (25 ° C) )] Was obtained.

[Acrylic resin (A-3)]
In the acrylic resin (A-1), a solution-like acrylic resin (A-1) is similarly prepared except that the polymerization components are changed to 69 parts of n-butyl acrylate, 30 parts of methyl acrylate, and 1 part of 2-hydroxyethyl acrylate. -3) [SP value: 10.033 (cal / cm ³ ) ^1/2 , weight average molecular weight: 600,000, glass transition temperature: -39.6 ° C, resin content: 35.0%, viscosity: 5,000 mPa · S (25 ° C.)] was obtained.

[Acrylic resin (A-4)]
In the acrylic resin (A-1), a solution-like acrylic resin (A-1) was obtained in the same manner except that the polymerization component was changed to 59 parts of n-butyl acrylate, 40 parts of methyl acrylate, and 1 part of 2-hydroxyethyl acrylate. -4) [SP value: 10.110 (cal / cm ³ ) ^1/2 , weight average molecular weight: 700,000, glass transition temperature: -33.6 ° C, resin content: 35.0%, viscosity: 6,000 mPa · S (25 ° C.)] was obtained.

[Acrylic resin (A-5)]
In the acrylic resin (A-1), the same applies except that the polymerization components were changed to 70 parts of n-butyl acrylate, 20 parts of methyl methacrylate, 0.1 part of 2-hydroxyethyl methacrylate, and 9.9 parts of acrylic acid. , Solution acrylic resin (A-5) [SP value: 10.163 (cal / cm ³ ) ^1/2 , weight average molecular weight: 500,000, glass transition temperature: -24.2 ° C, resin content: 35 .0%, viscosity: 8,000 mPa · s (25 ° C.)] was obtained.

[Acrylic resin (A-6)]
In the acrylic resin (A-1), the same applies except that the polymerization components were changed to 69.8 parts of n-butyl acrylate, 25 parts of methyl methacrylate, 0.2 parts of 2-hydroxyethyl methacrylate, and 5 parts of acrylic acid. , Solution acrylic resin (A-6) [SP value: 9.995 (cal / cm ³ ) ^1/2 , weight average molecular weight: 450,000, glass transition temperature: -24.0 ° C, resin content: 35 0.0%, viscosity: 6,000 mPa · s (25 ° C.)] was obtained.

[Acrylic resin (A-7)]
In the acrylic resin (A-1), a solution-like acrylic resin (A-1) was obtained in the same manner except that the polymerization component was changed to 39 parts of n-butyl acrylate, 60 parts of methyl acrylate, and 1 part of 2-hydroxyethyl acrylate. -7) [SP value: 10.270 (cal / cm ³ ) ^1/2 , weight average molecular weight: 700,000, glass transition temperature: -21.0 ° C, resin content: 35.0%, viscosity: 10,000 mPa · S (25 ° C.)] was obtained.

[Acrylic resin (A-8)]
In the acrylic resin (A-1), the same applies except that the polymerization component was changed to 64.85 parts of n-butyl acrylate, 30 parts of methyl methacrylate, 5 parts of 2-hydroxyethyl methacrylate, and 0.15 part of acrylic acid. , Solution acrylic resin (A-8) [SP value: 9.996 (cal / cm ³ ) ^1/2 , weight average molecular weight: 450,000, glass transition temperature: -19.1 ° C, resin content: 35 0.0%, viscosity: 6,000 mPa · s (25 ° C.)] was obtained.

[Acrylic resin (A'-1)]
In the acrylic resin (A-1), solution acrylic in the same manner except that the polymerization component was changed to 92.8 parts of 2-ethylhexyl acrylate, 7 parts of 2-hydroxyethyl acrylate, and 0.2 part of acrylic acid. System resin (A'-1) [SP value: 9.550 (cal / cm ³ ) ^1/2 , weight average molecular weight: 1 million, glass transition temperature: -66.7 ° C, resin content: 35.0%, Viscosity: 4,000 mPa · s (25 ° C.)] was obtained.

[Acrylic resin (A'-2)]
In the acrylic resin (A-1), solution acrylic in the same manner except that the polymerization component was changed to 91.9 parts of 2-ethylhexyl acrylate, 0.1 part of 2-hydroxyethyl methacrylate, and 8 parts of acrylic acid. System resin (A'-2) [SP value: 9.530 (cal / cm ³ ) ^1/2 , weight average molecular weight: 600,000, glass transition temperature: -62.1 ° C, resin content: 35.0%, Viscosity: 2,000 mPa · s (25 ° C.)] was obtained.

[Acrylic resin (A'-3)]
In the acrylic resin (A-1), a solution-like acrylic resin is similarly prepared except that the polymerization component is changed to 59 parts of n-butyl acrylate, 36 parts of 2-ethylhexyl acrylate, and 5 parts of 2-hydroxyethyl acrylate. (A'-3) [SP value: 9.770 (cal / cm ³ ) ^1/2 , weight average molecular weight: 950,000, glass transition temperature: -59.6 ° C, resin content: 35.0%, viscosity: 3,000 mPa · s (25 ° C.)] was obtained.

[Acrylic resin (A'-4)]
The same applies to the acrylic resin (A-1) except that the polymerization component is changed to 45.9 parts of n-butyl acrylate, 46 parts of 2-ethylhexyl acrylate, 0.1 part of 2-hydroxyethyl methacrylate, and 8 parts of acrylic acid. Then, a solution acrylic resin (A'-4) [SP value: 9.787 (cal / cm ³ ) ^1/2 , weight average molecular weight: 550,000, glass transition temperature: -55.4 ° C, resin Minutes: 35.0%, viscosity: 1500 mPa · s (25 ° C.)] was obtained.

<Urethane (meth) acrylate compounds and ethylenically unsaturated compounds>
[Composition of Urethane Acrylate (B-1) and Dipentaerythritol Hexaacrylate (C-1)]
8.7 parts of isophorone diisocyanate, 91.3 parts of dipentaerythritol acrylate adduct (hydroxyl value 48 mgKOH / g), polymerization in a 4-neck flask equipped with a thermometer, agitator, water-cooled condenser, and nitrogen gas inlet. When 0.06 part of 2,6-di-tert-butyl cresol was charged as a banning agent and 0.01 part of dibutyltin dilaurate was charged as a reaction catalyst and reacted at 60 ° C., and the residual isocyanate group became 0.3% or less. The reaction was completed with (1) to obtain Composition I (weight average molecular weight 2,300). This composition I contained 45 parts of urethane acrylate (B-1) and 55 parts of dipentaerythritol hexaacrylate (C-1).
[Urethane acrylate (B-1)]
-A reaction product of isophorone diisocyanate and dipentaerythritol pentaacrylate [Ethylene unsaturated group: 10, SP value: 10.64 (cal / cm ³ ) ^1/2 ]
[Ethylene unsaturated compound (C-1)]
-Dipentaerythritol hexaacrylate [Ethylene unsaturated group: 6, SP value: 10.40 (cal / cm ³ ) ^1/2 ]

[Composition of Urethane Acrylate (B-2) and Pentaerythritol Tetraacrylate (C-2)]
19.2 parts of isophorone diisocyanate and 80.8 parts of pentaerythritol acrylate adduct (hydroxyl value 120 mgKOH / g) are charged in a flask equipped with a thermometer, agitator, a water-cooled condenser, and a nitrogen gas inlet, and polymerization is prohibited. 0.06 part of 2,6-di-tert-butyl cresol was charged as an agent, and 0.01 part of dibutyltin dilaurate was charged as a reaction catalyst, and the reaction was carried out at 60 ° C. when the residual isocyanate group became 0.3% or less. The reaction was completed to obtain Composition II (weight average molecular weight 1,600). This composition II contained 65 parts of urethane acrylate (B-2) and 35 parts of pentaerythritol tetraacrylate (C-2).
[Urethane acrylate (B-2)]
-A reaction product of isophorone diisocyanate and pentaerythritol triacrylate [Ethylene unsaturated group: 6, SP value: 10.73 (cal / cm ³ ) ^1/2 ]
[Ethylene unsaturated compound (C-2)]
-Pentaerythritol tetraacrylate [Ethylene unsaturated group: 4, SP value: 10.34 (cal / cm ³ ) ^1/2 ]

[Composition of Urethane Acrylate (B-3) and Dipentaerythritol Hexaacrylate (C-1)]
16.3 parts of isophorone diisocyanate, 83.7 parts of dipentaerythritol acrylate adduct (hydroxyl value 98 mgKOH / g), polymerization in a 4-neck flask equipped with a thermometer, agitator, water-cooled condenser, and nitrogen gas inlet. When 0.06 part of 2,6-di-tert-butyl cresol was charged as a banning agent and 0.01 part of dibutyltin dilaurate was charged as a reaction catalyst and reacted at 60 ° C., and the residual isocyanate group became 0.3% or less. The reaction was terminated with (1) to obtain Composition III (weight average molecular weight 5300). This composition III contained 37.5 parts of urethane acrylate (B-3) and 12.5 parts of dipentaerythritol hexaacrylate (C-1).
[Urethane acrylate (B-3)]
-A reaction product of isophorone diisocyanate and dipentaerythritol pentaacrylate [Ethylene unsaturated group: 10, SP value: 10.64 (cal / cm ³ ) ^1/2 ]
[Ethylene unsaturated compound (C-1)]
-Dipentaerythritol hexaacrylate [Ethylene unsaturated group: 6, SP value: 10.40 (cal / cm ³ ) ^1/2 ]

<Photopolymerization initiator>
[Photopolymerizable initiator (D-1)]
・ Omnirad 184 (manufactured by IGM RESIN)

<Crosslinking agent>
[Crosslinking agent (E-1)]
・ Coronate L-55E (isocyanate cross-linking agent, manufactured by Tosoh Corporation)

<< Example 1 >>
[Preparation of active energy ray-curable release type pressure-sensitive adhesive composition]
286 parts of the acrylic resin (A-1) (resin content 35%), 50 parts of the composition I [22.5 parts of the urethane acrylate (B-1), 27.5 parts of the ethylenically unsaturated compound (C-1)) ], 2.1 parts of photopolymerizable initiator (D-1), 9.7 parts of cross-linking agent (E-1) (5.4 parts in terms of active ingredient), and 30 parts of toluene as a diluting solvent are mixed and activated. An energy ray-curable release type pressure-sensitive adhesive composition was obtained.

[Preparation of peelable adhesive sheet]
After applying the obtained active energy ray-curable release type pressure-sensitive adhesive composition as a base sheet on an easily adhesive polyethylene terephthalate film (thickness 50 μm) (manufactured by Toray Industries, Inc., “Lumilar T60”) with an applicator. , Dry at 100 ° C for 3 minutes, attach to a release film (“SP-PET 38 01-BU” manufactured by Mitsui Chemicals Tohcello Co., Ltd.), and age at 40 ° C for 3 days to release the adhesive sheet (adhesive). The thickness of the agent layer was 25 μm).
The following evaluation was performed using the obtained peelable adhesive sheet.

[Adhesive strength: Before irradiation with ultraviolet rays (UV)]
A test piece having a size of 25 mm × 100 mm was prepared from the peelable adhesive sheet obtained above, the release film was peeled off, and then the stainless steel plate (SUS304BA plate) was placed in an atmosphere of 23 ° C. and a relative humidity of 50%. A rubber roller having a mass of 2 kg was reciprocated twice to apply pressure, and the film was allowed to stand for 30 minutes in the same atmosphere, and then the peel strength (N / 25 mm) was measured at a peeling speed of 300 mm / min at 180 degrees.
(Evaluation criteria)
◎ ・ ・ ・ 10N / 25mm or more ○ ・ ・ ・ 5N / 25mm or more and less than 10N / 25mm △ ・ ・ ・ 1N / 25mm or more and less than 5N / 25mm × ・ ・ ・ 1N / 25mm or less, or adhesive residue occurs

[Adhesive strength: after irradiation with ultraviolet rays (UV)]
A test piece having a size of 25 mm × 100 mm was prepared from the peelable adhesive sheet obtained above, the release film was peeled off, and the stainless steel plate (SUS304BA plate) was placed in an atmosphere of 23 ° C. and a relative humidity of 50%. A rubber roller with a mass of 2 kg is reciprocated twice to apply pressure, and after leaving it in the same atmosphere for 30 minutes, a conveyor speed of 5.1 m / min from a height of 18 cm is used using an 80 W high-pressure mercury lamp and one lamp. UV irradiation (cumulative irradiation amount 200 mJ / cm ² ) was performed. Further, after allowing to stand for 30 minutes in an atmosphere of 23 ° C. and a relative humidity of 50%, the peeling strength (N / 25 mm) of 180 degrees was measured at a peeling speed of 300 mm / min.
(Evaluation criteria)
◎ ・ ・ ・ 0.2N / 25mm or more ○ ・ ・ ・ 0.2N / 25mm or more, 0.5N / 25mm or less Δ ・ ・ ・ 0.5N / 25mm or more and less than 1N / 25mm × ・ ・ ・ 1N / 25mm or more Or, glue residue occurs

[Stain resistance: before ultraviolet (UV) irradiation]
The peelable adhesive sheet obtained above is attached to the surface of a 4-inch square stainless steel plate (SUS304BA plate) to which no foreign matter is attached, and left to stand in an atmosphere of 23 ° C. and 65% relative humidity for 1 hour. The peelable adhesive sheet was peeled off from the surface of the stainless steel plate, and the peeled stainless steel plate was visually evaluated as follows.
(Evaluation criteria)
○ ・ ・ ・ No glue residue △ ・ ・ ・ Slight glue residue × ・ ・ ・ Glue residue

[Stain resistance: after ultraviolet (UV) irradiation]
The peelable adhesive sheet obtained above is attached to the surface of a 4-inch square stainless steel plate (SUS304BA plate) to which no foreign matter is attached, and the mixture is allowed to stand in an atmosphere of 23 ° C. and 65% relative humidity for 1 hour. Ultraviolet irradiation (integrated irradiation amount 200 mJ / cm ² ) was performed from a height of 18 cm at a conveyor speed of 5.1 m / min using one 80 W high-pressure mercury lamp. Then, the peelable adhesive sheet was peeled off from the surface of the stainless steel plate, and the peeled stainless steel plate was visually evaluated as follows.
(Evaluation criteria)
○ ・ ・ ・ No glue residue △ ・ ・ ・ Slight glue residue × ・ ・ ・ Glue residue

[Haze value]
The diffusion transmittance and total light transmittance of the release-type adhesive sheet from which the release film was peeled off were measured using HAZE MATER NDH2000 (manufactured by Nippon Denshoku Kogyo Co., Ltd.), and the obtained diffusion transmittance and total light transmittance values were obtained. Was substituted into the following equation to obtain the haze value. The higher the haze value, the more uneven the components in the active energy ray-curable release type pressure-sensitive adhesive composition. The haze value is a value including the base material sheet.
Haze value (%) = (diffusion transmittance / total light transmittance) x 100
(Evaluation criteria)
◎ ・ ・ ・ Less than 1% ○ ・ ・ ・ 1% or more and less than 2% △ ・ ・ ・ 2% or more and less than 3% × ・ ・ ・ 3% or more

<< Examples 2-14, Comparative Examples 1-9 >>
An active energy ray-curable release type pressure-sensitive adhesive composition was obtained in the same manner as in Example 1 except that each component was blended as shown in Tables 2 and 3 below. Further, the obtained active energy ray-curable release type pressure-sensitive adhesive compositions of Examples 2 to 14 and Comparative Examples 1 to 9 were evaluated in the same manner as in Example 1. The evaluation results of Examples 2 to 14 and Comparative Examples 1 to 9 are shown in Table 4 below together with the evaluation results of Example 1.

As shown in Table 4 above, an acrylic resin (A) having an SP value of a specific solubility parameter or higher, a urethane (meth) acrylate compound (B) having a specific number of ethylenically unsaturated groups, and an ethylenically unsaturated group. It contains a saturated compound (C), a photopolymerizable initiator (D) and a cross-linking agent (E), and the total content of the urethane (meth) acrylate-based compound (B) and the ethylenically unsaturated compound (C) is specific. In the active energy ray-curable release type pressure-sensitive adhesive compositions of Examples 1 to 14, which are in the range, since the haze value when this is used as the pressure-sensitive adhesive layer of the peel-type pressure-sensitive adhesive sheet is low, each component is active energy ray-curable. It can be seen that it is in a uniform state in the release-type pressure-sensitive adhesive composition. The peelable pressure-sensitive adhesive sheet using Examples 1 to 14 was excellent in adhesive properties before and after irradiation with active energy rays, and was also excellent in stain resistance to the member to be processed.

On the other hand, in Comparative Examples 1 to 4 using an acrylic resin in which the SP value in the solubility parameter was less than a specific value, since the haze value was high, each component was not in a uniform state, and this was used. The peelable pressure-sensitive adhesive sheet was inferior in adhesive properties and inferior in stain resistance to the member to be processed.

Further, the release-type pressure-sensitive adhesive sheet using Comparative Examples 5 to 9 in which the total content of the urethane (meth) acrylate-based compound (B) and the ethylenically unsaturated compound (C) is out of a specific range has adhesive properties. It was inferior or inferior in stain resistance to the member to be processed.

Although the specific embodiments of the present invention have been shown in the above examples, the above examples are merely examples and are not to be interpreted in a limited manner. Various variations apparent to those skilled in the art are intended to be within the scope of the present invention.

The active energy ray-curable release type pressure-sensitive adhesive composition of the present invention is suitably used for a temporary surface protection pressure-sensitive adhesive film when processing semiconductor wafers, printed circuit boards, glass processed products, metal plates, plastic plates and the like. Can be done.

Claims (6)

Acrylic resin (A), urethane (meth) acrylate compound (B), ethylenically unsaturated compound (C) excluding the above urethane (meth) acrylate compound (B), photopolymerizable initiator (D) and cross-linking. A release-type pressure-sensitive adhesive composition containing the agent (E), wherein the SP value in the solubility parameter of the acrylic resin (A) is 9.9 (cal / cm ³ ) ^1/2 or more, and the above-mentioned urethane ( The meta) acrylate-based compound (B) has 2 to 20 ethylenically unsaturated groups, and the above ethylenically unsaturated compound (C) has 2 to 10 ethylenically unsaturated groups, and The total content of the urethane (meth) acrylate compound (B) and the ethylenically unsaturated compound (C) is 20 to 100 parts by weight with respect to 100 parts by weight of the acrylic resin (A). Active energy ray-curable release type pressure-sensitive adhesive composition. The active energy ray-curable release type pressure-sensitive adhesive composition according to claim 1, wherein the acrylic resin (A) has a glass transition temperature of −50 to 20 ° C. The weight content ratio (B: C) of the urethane (meth) acrylate compound (B) and the ethylenically unsaturated compound (C) is 99.9: 0.1: 0.1: 99.9. The active energy ray-curable release type pressure-sensitive adhesive composition according to claim 1 or 2. Claims 1 to 3 characterized in that the urethane (meth) acrylate compound (B) is a reaction product of a hydroxyl group-containing (meth) acrylate compound (b1) and a polyvalent isocyanate compound (b2). The active energy ray-curable release type pressure-sensitive adhesive composition according to any one of the above. The active energy ray-curable release type pressure-sensitive adhesive composition according to any one of claims 1 to 4, wherein the cross-linking agent (E) is an isocyanate-based cross-linking agent. A release-type pressure-sensitive adhesive sheet according to any one of claims 1 to 5, wherein the active energy ray-curable release-type pressure-sensitive adhesive composition has a pressure-sensitive adhesive layer crosslinked by a cross-linking agent (E).