JP2020063425A - Active energy ray curable peeling type adhesive composition and peeling type adhesive sheet - Google Patents

Abstract

To provide an active energy ray curable peeling type adhesive composition which is formed into an adhesive that has good adhesive force before irradiation with active energy rays and is excellent in heat resistance, and can obtain an adhesive excellent in peelability (stain resistance and fine stickiness) after irradiation with active energy rays even after heating.SOLUTION: An active energy ray curable peeling type adhesive composition contains an acrylic resin (A), a urethane (meth)acrylate-based compound (B), an isocyanate-based crosslinking agent (C) and a photopolymerizable initiator (D), in which the isocyanate-based crosslinking agent (C) is an alicyclic or aromatic polyvalent isocyanate (c1) having at least one isocyanate group bonded to primary carbon.SELECTED DRAWING: None

Description

  The present invention relates to an active energy used in a pressure-sensitive adhesive layer of a peelable pressure-sensitive adhesive sheet for temporary surface protection when processing a workpiece such as a semiconductor wafer, a printed circuit board, a glass processed product, a metal plate and a plastic plate. The present invention relates to a line-curable release adhesive composition and a release adhesive sheet.

  Conventionally, in processing steps such as fabrication of integrated circuits using semiconductor wafers and drilling, surface protection for temporarily protecting the surface of the workpiece for the purpose of preventing contamination or damage of the workpiece. Adhesive sheet is used. And in recent years, due to the miniaturization of processing technology and the thinning of members to be processed, an appropriate pressure-sensitive adhesive force is required for the members to be processed, while after finishing the role of surface protection, an adhesive sheet for surface protection is used. It is necessary to peel off the adhesive, and it is required that the adhesive can be peeled off with a light force when peeling. Further, in recent years, adhesive sheets for surface protection have been used not only for semiconductor wafers but also for processing various members.

  As a pressure-sensitive adhesive film or sheet for temporary surface protection, for example, Patent Document 1 discloses a radiation-polymerizable compound that is a urethane acrylate oligomer having a pressure-sensitive adhesive on the surface of a substrate and a weight average molecular weight of 3,000 to 10,000. There is disclosed a pressure-sensitive adhesive sheet obtained by applying a pressure-sensitive adhesive layer comprising It is described that the adhesive force with the adherend is drastically reduced by irradiating the adhesive sheet with ultraviolet rays when the adhesive sheet is peeled off.

  Further, in Patent Document 2, an acrylic adhesive having a weight average molecular weight of 200,000 or more and a glass transition temperature of −60 to −30 ° C., a hydroxyl group-containing acrylic compound having 3 or more acryloyl groups in the molecule, and diisocyanate. By using a urethane acrylate compound, which is a reaction product with a compound, there is disclosed a re-peeling pressure-sensitive adhesive in which the pressure-sensitive adhesive remains little during re-peeling.

  In addition, in recent years, in the manufacturing process of electronic components, it is not uncommon for components with an adhesive tape attached to be exposed to high temperatures. Therefore, the adhesive tape used in the manufacturing process of electronic components can withstand high temperature conditions. Heat resistance is also required, and in Patent Document 3, an energy ray easily peelable pressure-sensitive adhesive composition containing an acrylic polymer, an energy ray polymerizable oligomer, a polymerization initiator, and a crosslinking agent, It is disclosed to use a polymerization initiator having physical properties.

JP 62-153376 A JP, 11-293201, A JP 2012-012506 A

  However, in the technique disclosed in Patent Document 1 described above, although the adhesive strength after curing of the peelable pressure-sensitive adhesive is reduced, the pressure-sensitive adhesive remains on the member to be processed (paste residue) at the time of peeling, or in the dicing process of the semiconductor wafer. However, there are problems that the chips are scattered during dicing, and the chips are peeled off during expansion, which is still unsatisfactory.

  Further, in the technology disclosed in Patent Document 2, there is a description that the adhesive residue at the time of peeling is improved, but when an acrylic resin containing a carboxy group-containing monomer as a polymerization component is used, There is a concern that the material to be processed may be altered by the influence of the base.

  Further, in the technique disclosed in Patent Document 3, although the heat resistance is improved, the adhesive force before irradiation with active energy rays is not sufficient. Therefore, there is a demand for a peelable pressure-sensitive adhesive that has good adhesion before irradiation with active energy rays and is also excellent in heat resistance.

  Therefore, in the present invention, under such a background, the pressure-sensitive adhesive has good adhesive force before irradiation with active energy rays and is also excellent in heat resistance, and peelability (resistance to resistance after irradiation with active energy rays) even after heating. It is an object of the present invention to provide an active energy ray-curable release type pressure-sensitive adhesive composition that can obtain a pressure-sensitive adhesive having excellent stain resistance and slight pressure-sensitive adhesiveness.

  However, the present inventor has conducted extensive studies in view of such circumstances, and by using an isocyanate-based cross-linking agent having a specific structure, the adhesive force before irradiation with active energy rays is good, and the heat resistance is excellent. The present invention has found an active energy ray-curable release type adhesive composition which can be used as an adhesive agent and which is excellent in peelability (stain resistance and slight adhesiveness) after irradiation with active energy rays even after heating. Completed the invention.

That is, the present invention contains an acrylic resin (A), a urethane (meth) acrylate compound (B), an isocyanate crosslinking agent (C) and a photopolymerizable initiator (D), and the above isocyanate crosslinking agent ( C) is an alicyclic or aromatic polyvalent isocyanate having at least one isocyanate group bonded to primary carbon (c1), the active energy ray-curable peelable pressure-sensitive adhesive composition as a first summary. To do.
The present invention also provides a peelable pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer obtained by crosslinking the active energy ray-curable peelable pressure-sensitive adhesive composition according to the first aspect above with an isocyanate-based crosslinking agent (C), as a second aspect. To do.

  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 isocyanate crosslinking agent (C) and a photopolymerizable initiator (D). And the isocyanate cross-linking agent (C) is an alicyclic or aromatic polyvalent isocyanate (c1) having at least one isocyanate group bonded to primary carbon. Therefore, when this active energy ray-curable release type pressure-sensitive adhesive composition is used as the pressure-sensitive adhesive layer of the release type pressure-sensitive adhesive sheet, the adhesive strength before irradiation with active energy rays is good, and excellent in heat resistance, and Even after heating, the peelability (contamination resistance, slight tackiness) after irradiation with active energy rays can be made excellent.

  In addition, among the present invention, particularly, when the alicyclic or aromatic polyvalent isocyanate (c1) is a derivative of xylylene diisocyanate, the adhesive force before irradiation with active energy rays is better, In addition, the heat resistance is excellent, and the peelability (contamination resistance and slight adhesiveness) after irradiation with active energy rays is excellent even after heating.

  Further, among the present invention, particularly, when the alicyclic or aromatic polyvalent isocyanate (c1) is an adduct of a polyol compound, the adhesive force before irradiation with active energy rays is better, In addition, the heat resistance is excellent, and the peelability (contamination resistance and slight adhesiveness) after irradiation with active energy rays is excellent even after heating.

  And especially in this invention, when the content of the said isocyanate type crosslinking agent (C) is 0.1-10 weight part with respect to 100 weight part of acrylic resin (A), more active energy rays. The adhesive strength before irradiation is good, the heat resistance is excellent, and the peelability (contamination resistance, slight adhesiveness) after irradiation with active energy rays is excellent even after heating.

  Further, among the present invention, in particular, when the glass transition temperature (Tg) of the acrylic resin (A) is −60 to 0 ° C., the adhesive force before irradiation with active energy rays is more favorable, and The heat resistance is excellent, and the peelability (contamination resistance and slight adhesiveness) after irradiation with active energy rays is excellent even after heating.

  Further, among the present invention, particularly, 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). Further, the peelability (contamination resistance, slight adhesiveness) after irradiation with active energy rays becomes excellent.

  Further, when the active energy ray-curable release pressure-sensitive adhesive composition of the present invention is a release pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer crosslinked with an isocyanate-based crosslinking agent (C), the release pressure-sensitive adhesive sheet has active energy The adhesive strength before irradiation with rays is good, the heat resistance is excellent, and the peelability (contamination resistance, slight adhesion) after irradiation with active energy rays is excellent even after heating.

Hereinafter, modes 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.
Further, the acrylic resin is a resin obtained by polymerizing a polymerization component containing at least one kind of (meth) acrylate monomer.
In addition, in the present invention, the “sheet” is not particularly distinguished from “film” and “tape” and is described as a meaning including these.

  The active energy ray-curable release-type pressure-sensitive adhesive composition of the present invention is usually a pressure-sensitive adhesive of a release-type pressure-sensitive adhesive sheet, which is premised to be peeled after being bonded to a member to be processed such as a metal plate, a plastic plate and a semiconductor wafer. Used as an agent. The release-type pressure-sensitive adhesive sheet is one in which an active energy ray-curable release-type pressure-sensitive adhesive composition is applied onto a substrate sheet to form a pressure-sensitive adhesive layer, and after being bonded to a member to be processed, By irradiating with active energy rays, the pressure-sensitive adhesive is cured and its adhesive strength is reduced, so that it can be easily peeled 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 isocyanate crosslinking agent (C) and a photopolymerizable initiator (D). It contains.
Hereinafter, each component will be described.

[Acrylic resin (A)]
The acrylic resin (A) used in the present invention comprises a (meth) acrylic acid alkyl ester monomer (a1), a functional group-containing monomer (a2), and, if necessary, another copolymerizable monomer (a3). It is obtained by copolymerization.

  In the (meth) acrylic acid alkyl ester-based monomer (a1), the alkyl group has usually 1 to 20 carbon atoms, preferably 1 to 12, particularly preferably 1 to 8, and further preferably 1 to 4. . If the carbon number is too large, it is difficult to uniformly mix the acrylic resin (A) and the urethane (meth) acrylate compound (B) to be obtained, and the adhesive residue on the processed member tends to occur.

Specific examples of the (meth) acrylic acid alkyl ester-based monomer (a1) include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, and tert-. Butyl (meth) acrylate, n-propyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl acrylate, isodecyl (meth) acrylate, lauryl ( Aliphatic (meth) acrylic acid alkyl esters such as (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate; cyclohexyl (meth) acrylate, isobornyl (meth) acrylate ) Cycloaliphatic (meth) acrylic acid alkyl esters such as acrylate. These may be used alone or in combination of two or more.
Among the above-mentioned (meth) acrylic acid alkyl ester-based monomers (a1), methyl (meth) acrylate and n-butyl (meth) acrylate are preferred in view of copolymerizability, adhesive property, handleability and availability of raw materials. , 2-ethylhexyl (meth) acrylate is preferably used.

  The content of the (meth) acrylic acid alkyl ester-based monomer (a1) in the polymerization component is usually 30 to 99% by weight, preferably 40 to 98% by weight, particularly preferably 50 to 95% by weight. is there. If the content is too low, the adhesive strength before irradiation with active energy rays tends to be lowered, and if the content is too high, the adhesive strength before irradiation with active energy rays tends to be too high.

  Examples of the functional group-containing monomer (a2) include a hydroxyl group-containing monomer, a carboxy group-containing monomer, an amino group-containing monomer, an amide group-containing monomer, a glycidyl group-containing monomer, a sulfone group-containing monomer, and an acetoacetyl group-containing monomer. it can. These functional group-containing monomers can be used alone or in combination of two or more kinds.

  The content of the functional group-containing monomer (a2) in the polymerization component is usually 0.01 to 30% by weight, preferably 0.2 to 20% by weight, more preferably 0.5 to 10% by weight. . If the content is too large, crosslinking tends to occur before the drying step, and the coating property tends to cause a problem. If the content is too small, the degree of crosslinking is reduced, and the contamination of the work member is likely to increase. Tends to become.

The hydroxyl group-containing monomer is preferably a hydroxyl group-containing (meth) acrylate-based monomer, and specifically, for example, 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 5-hydroxypentyl. (Meth) acrylic acid hydroxyalkyl ester such as (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, caprolactone-modified monomer such as caprolactone-modified 2-hydroxyethyl (meth) acrylate, diethylene glycol Oxyalkylene-modified monomers such as (meth) acrylate and polyethylene glycol (meth) acrylate, primary hydroxyl group-containing monomers such as 2-acryloyloxyethyl-2-hydroxyethylphthalic acid A secondary hydroxyl group-containing monomer such as 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 3-chloro-2-hydroxypropyl (meth) acrylate; 2,2-dimethyl2-hydroxyethyl (meth ) Examples thereof include tertiary hydroxyl group-containing monomers such as acrylate.
Among the above-mentioned hydroxyl group-containing monomers, primary hydroxyl group-containing monomers are preferable in terms of excellent reactivity with the isocyanate-based crosslinking agent (C) described below, and particularly 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 20% by weight, preferably 0.2 to 10% by weight, more preferably 0.5 to 5% by weight. If the content is too large, crosslinking tends to occur before the drying step, and the coating property tends to cause a problem. If the content is too small, the degree of crosslinking is reduced, and the contamination of the work member is likely to increase. Tends to become.

  Examples of the carboxy group-containing monomer include (meth) acrylic acid, (meth) acrylic acid dimer, crotonic acid, maleic acid, maleic anhydride, fumaric acid, citraconic acid, glutaconic acid, itaconic acid, acrylamide N-glycolic acid. , Cinnamic acid and the like. Among them, (meth) acrylic acid is preferably used in terms of copolymerizability.

  The content of the carboxy group-containing monomer in the polymerization component is usually 1% by weight or less, preferably 0.5% by weight or less, more preferably 0.3% by weight or less. If the content is too large, the material to be processed tends to be deteriorated, and crosslinking tends to occur before the drying step, so that the coating property tends to have a problem.

  Examples of the amino group-containing monomer include aminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, and the like.

  The content of the amino group-containing monomer in the polymerization component is usually 30% by weight or less, preferably 25% by weight or less, more preferably 20% by weight or less. If the content is too large, crosslinking tends to proceed before the drying step, which tends to cause problems in coatability.

  Examples of the amide group-containing monomer include ethoxymethyl (meth) acrylamide, n-butoxymethyl (meth) acrylamide, (meth) acryloylmorpholine, dimethyl (meth) acrylamide, diethyl (meth) acrylamide, dimethylaminopropylacrylamide, ( (Meth) acrylamide (meth) acrylamide-based monomers such as N-methylol (meth) acrylamide.

  The content of the amide group-containing monomer in the polymerization component is usually 30% by weight or less, preferably 25% by weight or less, more preferably 20% by weight or less. If the content is too large, crosslinking tends to proceed before the drying step, which tends to cause problems in coatability.

  Examples of the glycidyl group-containing monomer include glycidyl methacrylate and allyl glycidyl methacrylate.

  The content of the glycidyl group-containing monomer in the polymerization component is usually 1% by weight or less, preferably 0.5% by weight or less, more preferably 0.3% by weight or less. If the content is too large, crosslinking tends to proceed before the drying step, which tends to cause problems in coatability.

  Examples of the sulfonic acid group-containing monomer include olefin sulfonic acids such as ethylene sulfonic acid, allyl sulfonic acid and methallyl sulfonic acid, 2-acrylamido-2-methylolpropane sulfonic acid, styrene sulfonic acid and salts thereof. .

  The content of the sulfonic acid group-containing monomer in the polymerization component is usually 1% by weight or less, preferably 0.5% by weight or less, and more preferably 0.3% by weight or less. If the content is too large, crosslinking tends to proceed before the drying step, which tends to cause problems in coatability.

  Examples of the acetoacetyl group-containing monomer include 2- (acetoacetoxy) ethyl (meth) acrylate and allyl acetoacetate.

  The content of the acetoacetyl group-containing monomer in the polymerization component is usually 10% by weight or less, preferably 5% by weight or less, and more preferably 1% by weight or less. If the content is too large, crosslinking tends to proceed before the drying step, which tends to cause problems in coatability.

  Examples of the other copolymerizable monomer (a3) include vinyl acetate, vinyl propionate, vinyl stearate, vinyl benzoate, and other carboxylic acid vinyl ester monomers; phenyl (meth) acrylate, benzyl (meth) acrylate, and phenoxy. Monomers containing aromatic rings such as ethyl (meth) acrylate, phenyldiethylene glycol (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, styrene, α-methylstyrene; biphenyloxyethyl (meth) acrylate and the like. Biphenyloxy structure-containing (meth) acrylic acid ester-based monomer; 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, methoxydiethylene glycol (meth) acrylate, eth Monomers containing alkoxy groups or oxyalkylene groups such as sidiethylene glycol (meth) acrylate, methoxy polyethylene glycol (meth) acrylate, polypropylene glycol mono (meth) acrylate; acrylonitrile, methacrylonitrile, vinyl chloride, vinylidene chloride, alkyl vinyl ether, Examples thereof include vinyltoluene, vinylpyridine, vinylpyrrolidone, itaconic acid dialkyl ester, fumaric acid dialkyl ester, allyl alcohol, acrylic chloride, methyl vinyl ketone, allyl trimethyl ammonium chloride, and dimethyl allyl vinyl ketone. These may be used alone or in combination of two or more.

  The content of the other copolymerizable monomer (a3) 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 the amount of the other copolymerizable monomer (a3) is too large, the adhesive property tends to deteriorate.

  In the present invention, the above-mentioned (meth) acrylic acid alkyl ester-based monomer (a1), functional group-containing monomer (a2), and other copolymerizable monomer (a3) are polymerized as a copolymerization component to give a (meth) acrylic-based monomer. The resin (A) is produced, but as such a polymerization method, it can be appropriately carried out by a conventionally known method such as solution radical polymerization, suspension polymerization, bulk polymerization and emulsion polymerization. Among them, the solution radical polymerization is preferable because it allows the acrylic resin (A) to be safely and stably produced with an arbitrary monomer composition.

  In the solution radical polymerization, for example, in an organic solvent, a monomer component such as a (meth) acrylic acid alkyl ester-based monomer (a1), a functional group-containing monomer (a2), and another copolymerizable monomer (a3) and polymerization initiation The agent may be mixed or added dropwise and polymerized at reflux or usually at 50 to 98 ° C. 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, isopropyl alcohol. And aliphatic alcohols such as acetone, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone.

  As the above-mentioned polymerization initiator, an ordinary radical polymerization initiator can be used, and specifically, azo-based polymerization initiators such as azobisisobutyronitrile and azobisdimethylvaleronitrile, benzoyl peroxide, and lauroyl peroxide. Examples thereof include peroxide-based polymerization initiators such as oxide, di-tert-butyl peroxide, cumene hydroperoxide and the like.

  The glass transition temperature (Tg) of the acrylic resin (A) obtained by the above polymerization method is preferably −60 to 0 ° C., particularly −55 to −5 ° C., and further −50 to −10 ° C. Particularly preferably, it is -40 to -20 ° C. If the glass transition temperature is too high, the tackiness tends to decrease, and if it is too low, the stain resistance to the workpiece tends to increase.

ここで、アクリル系樹脂（Ａ）を構成するモノマーをホモポリマーとした際のガラス転移温度は、通常、示差走査熱量計（ＤＳＣ）により測定されるものであり、ＪＩＳ Ｋ ７１２１−１９８７や、ＪＩＳ Ｋ ６２４０に準拠した方法で測定することができる。 The glass transition temperature (Tg) is a value calculated by applying the glass transition temperature and weight fraction when the respective monomers constituting the acrylic resin (A) are homopolymers to the following Fox equation. Is.

Here, the glass transition temperature when the monomer constituting the acrylic resin (A) is a homopolymer is usually measured by a differential scanning calorimeter (DSC), and may be measured according to JIS K 7121-1987 or JIS. It can be measured by a method according to K 6240.

  The weight average molecular weight of the acrylic resin (A) is usually 100,000 to 2,000,000, preferably 150,000 to 1,500,000, particularly preferably 200,000 to 1,200,000, and particularly preferably 300,000 to 1,000,000. . If the weight average molecular weight is too small, the stain resistance to the member to be processed tends to be high, and if it is too large, the coatability tends to deteriorate and the cost tends to be disadvantageous.

  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 dispersity is too high, the contamination of the member to be processed tends to increase. The lower limit of the dispersity is usually 1.1 from the viewpoint of manufacturing limit.

The weight average molecular weight of the acrylic resin (A) is a weight average molecular weight in terms of standard polystyrene molecular weight, and is a high-performance liquid chromatograph (manufactured by Japan Waters, "Waters 2695 (main body)" and "Waters 2414 (detector)". ) Column: Shodex GPC KF-806L (exclusion limit molecular weight: 2 × 10 ⁷ , separation range: 100 to 2 × 10 ⁷ , theoretical plate number: 10,000 plates / piece, packing material: styrene-divinylbenzene co-weight) The number average molecular weight can be obtained by the same method, which is measured by using three coalescing and filler particle sizes: 10 μm in series.

[Urethane (meth) acrylate compound (B)]
The urethane (meth) acrylate 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). Or a urethane (meth) acrylate compound (B2) which is a reaction product of a hydroxyl group-containing (meth) acrylate compound (b1), a polyvalent isocyanate compound (b2) and a polyol compound (b3). May be. Among them, in the present invention, it is preferable to use the urethane (meth) acrylate compound (B1) from the viewpoint of releasability after irradiation with active energy rays.
In the present invention, the urethane (meth) acrylate compound (B) may be used alone or in combination of two or more.

The hydroxyl group-containing (meth) acrylate compound (b1) is preferably one having one hydroxyl group, and examples thereof include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 2-hydroxybutyl (meth). ) Acrylate, 4-hydroxybutyl (meth) acrylate, hydroxyalkyl (meth) acrylate such as 6-hydroxyhexyl (meth) acrylate, 2-hydroxyethylacryloyl phosphate, 2- (meth) acryloyloxyethyl-2-hydroxypropyl Phthalate, caprolactone-modified 2-hydroxyethyl (meth) acrylate, dipropylene glycol (meth) acrylate, fatty acid-modified glycidyl (meth) acrylate, polyethylene glycol mono (meth) acrylate , Polypropylene glycol mono (meth) acrylate, 2-hydroxy-3- (meth) acryloyloxypropyl (meth) acrylate and the like, a hydroxyl group-containing (meth) acrylate compound containing one ethylenically unsaturated group; glycerin di ( (Meth) acrylate, 2-hydroxy-3-acryloyl-oxypropyl methacrylate and other hydroxyl group-containing (meth) acrylate compounds containing two ethylenically unsaturated groups; pentaerythritol tri (meth) acrylate, caprolactone modified pentaerythritol tri ( (Meth) acrylate, ethylene oxide modified pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, caprolactone modified dipentaerythritol penta (meth) acrylate Hydroxyl group-containing containing an ethylenically unsaturated group such as ethylene oxide modified dipentaerythritol penta (meth) acrylate 3 or more (meth) acrylate compounds, and the like.
The hydroxyl group-containing (meth) acrylate compound (b1) can be used alone or in combination of two or more kinds.

  Among these, a hydroxyl group-containing (meth) acrylate compound (b1) containing three or more ethylenically unsaturated groups is preferable from the viewpoint of excellent reactivity and versatility, and pentaerythritol tri (meth) acrylate or dipentaerythritol. Erythritol penta (meth) acrylate is particularly preferred.

Examples of the polyvalent isocyanate compound (b2) include aromatic compounds such as tolylene diisocyanate, diphenylmethane diisocyanate, polyphenylmethane polyisocyanate, modified diphenylmethane diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, phenylene diisocyanate, and naphthalene diisocyanate. Aliphatic polyisocyanates such as hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, lysine diisocyanate, lysine triisocyanate; hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, norbornene diisocyanate, etc. Group polyvalent isocyanate; or Isocyanurate or multimeric compounds of these polyvalent isocyanates, allophanate type polyisocyanates, burette type polyisocyanates, water dispersion type polyisocyanates (for example, "Aquanate 100", "Aquanate 110", "Aquanate 110" manufactured by Nippon Polyurethane Industry Co., Ltd., "Aquanate 200", "Aquanate 210", etc.) and the like.
The polyvalent isocyanate compounds (b2) can be used alone or in combination of two or more.

  Among these, in terms of excellent reactivity and versatility, aliphatic diisocyanates such as hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, lysine diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, norbornene Alicyclic diisocyanates such as diisocyanate are preferable, and isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, and hexamethylene diisocyanate are particularly preferable, and isophorone diisocyanate and hexamethylene diisocyanate are more preferable.

  The polyol-based compound (b3) may be a compound containing two or more hydroxyl groups, and examples thereof include an aliphatic polyol, an alicyclic polyol, a polyether-based polyol, a polyester-based polyol, a polycarbonate-based polyol, and a polyolefin-based polyol. , Polybutadiene-based polyols, polyisoprene-based polyols, (meth) acrylic-based polyols, polysiloxane-based polyols, and the like. These can be used alone or in combination of two or more.

  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, 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 -Two hydroxyl groups such as octanediol Aliphatic alcohols containing, sugar alcohols such as xylitol or sorbitol, glycerol, trimethylolpropane, fatty alcohols, etc., containing three or more hydroxyl groups such as trimethylol ethane.

  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-based polyol include alkylene structure-containing polyether-based polyols such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polybutylene glycol, polypentamethylene glycol, and polyhexamethylene glycol, and polyalkylene glycols thereof. Random or block copolymers can be used.

  Examples of the polyester-based polyol include a condensation polymer of a polyhydric alcohol and a polycarboxylic acid; a ring-opening polymer of a cyclic ester (lactone); a polyhydric alcohol, a polycarboxylic acid, and a cyclic ester. And the like.

Examples of the polyhydric alcohol include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, trimethylene glycol, 1,4-tetramethylene diol, 1,3-tetramethylene diol, 2-methyl-1,3-trimethylene. Methylene diol, 1,5-pentamethylene diol, neopentyl glycol, 1,6-hexamethylene diol, 3-methyl-1,5-pentamethylene diol, 2,4-diethyl-1,5-pentamethylene diol, glycerin , Trimethylolpropane, trimethylolethane, cyclohexanediols (1,4-cyclohexanediol, etc.), bisphenols (bisphenol A, etc.), sugar alcohols (xylitol, sorbitol, etc.), and the like.
Examples of the polycarboxylic 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 dodecanedioic acid; 1,4 Alicyclic dicarboxylic acid such as cyclohexanedicarboxylic acid; aromatic dicarboxylic acid such as terephthalic acid, isophthalic acid, orthophthalic acid, 2,6-naphthalenedicarboxylic acid, paraphenylenedicarboxylic acid and trimellitic acid.
Examples of the cyclic ester include propiolactone, β-methyl-δ-valerolactone, ε-caprolactone and the like.

Examples of the polycarbonate-based polyol include a reaction product of a polyhydric alcohol and phosgene; a ring-opening polymerization product of a cyclic carbonic acid ester (alkylene carbonate or the like).
Examples of the polyhydric alcohol include the 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. To be
The polycarbonate-based polyol may be, for example, a compound having a carbonate bond in the molecule and a hydroxyl group at the terminal, and may have an ester bond as well as the carbonate bond.

  Examples of the polyolefin-based polyols 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 end thereof.

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

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

  Examples of the (meth) acrylic polyol include those having at least two hydroxyl groups in the molecule of the polymer or copolymer of the (meth) acrylic acid ester. Examples of the ester include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, and (meth) acrylate. ) 2-Ethylhexyl acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, octadecyl (meth) acrylate, and the like (meth) acrylic acid alkyl esters and the like.

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

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

  The weight average molecular weight of the polyol compound (b3) is preferably 60 to 3,000, particularly preferably 100 to 1,000, and further preferably 150 to 800. If the weight average molecular weight of the polyol compound (b3) is too large, it will be difficult to uniformly mix the urethane (meth) acrylate compound (B2) and the acrylic resin (A) to be obtained, and the adhesive residue on the workpiece will remain. It tends to occur easily. If the weight average molecular weight of the polyol compound (b3) is too small, the pressure-sensitive adhesive layer tends to crack easily 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 a urethane (meth) acrylate-based compound (B1), the hydroxyl group-containing (meth) acrylate-based compound (b1) and the polyvalent isocyanate-based compound (b2) are combined with the urethane (meth) acrylate-based compound (B2). In the case of 1), the polyol-based compound (b3) can be further prepared by charging the reaction mixture in a reactor all at once or separately and subjecting it to a urethanization reaction by a known reaction means. In the case of producing the urethane (meth) acrylate compound (B2), the reaction product obtained by previously reacting the polyol compound (b3) with the polyvalent isocyanate compound (b2) contains a hydroxyl group ( The method of reacting the (meth) acrylate compound (b1) is useful in terms of stability of the urethanization reaction and reduction of by-products.

  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 examples of such a reaction catalyst include dibutyl Organometallic compounds such as tin dilaurate, trimethyltin hydroxide and tetra-n-butyltin, metal salts such as zinc octenoate, tin octenoate, tin octylate, cobalt naphthenate, stannous chloride and stannic chloride, Triethylamine, benzyldiethylamine, 1,4-diazabicyclo [2,2,2] octane, 1,8-diazabicyclo [5,4,0] undecene, N, N, N ', N'-tetramethyl-1,3- Amine-based catalysts such as butanediamine and N-ethylmorpholine, bismuth nitrate, bismuth bromide, bismuth iodide, bismuth sulfide Other, organic bismuth compounds such as dibutyl bismuth dilaurate, dioctyl bismuth dilaurate, 2-ethylhexanoic acid bismuth salt, naphthenic acid bismuth salt, isodecanic acid bismuth salt, neodecanoic acid bismuth salt, lauric acid bismuth salt, maleic acid bismuth salt, Bismuth-based catalysts such as bismuth stearate, bismuth oleate, bismuth linoleate, bismuth acetate, bismuth ribis neodecanoate, bismuth disalicylate, bismuth digallate and other organic acids, inorganic zirconium , Organic zirconium, zirconium-based catalysts such as zirconium alone, and those in which two or more kinds of catalysts such as zinc 2-ethylhexanoate / zirconium tetraacetylacetonate are used in combination, among which dibutyltin dilaurate, 1,8 Diazabicyclo [5,4,0] undecene is preferred. In addition, these catalysts can be used individually or in combination of 2 or more types.

  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 which 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 family members can be used.

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

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

The urethane (meth) acrylate compound (B) thus obtained preferably has 4 to 20 ethylenically unsaturated groups, more preferably 4 to 20 from the viewpoint of releasability after irradiation with active energy rays. It is 18 and particularly preferably 6 to 15.
If the number of such ethylenically unsaturated groups is too large, the crosslinking density after irradiation with active energy rays becomes too large, and cracks easily occur in the pressure-sensitive adhesive layer, and if the number is too small, sufficient crosslinking density cannot be obtained, and therefore the active energy There is a tendency for peeling to become difficult after irradiation with rays.

  The weight average molecular weight of the urethane (meth) acrylate compound (B) is usually 500 to 10,000, preferably 750 to 5,000, and more preferably 1,000 to 4,000. If the weight average molecular weight is too large, the viscosity of the urethane (meth) acrylate compound (B) increases, the compatibility with the acrylic resin (A) decreases, and the adhesive residue on the workpiece tends to remain easily. There is. If the weight average molecular weight is too small, the urethane (meth) acrylate compound (B) tends to bleed from the pressure-sensitive adhesive sheet to easily cause adhesive residue.

  The weight average molecular weight of the urethane (meth) acrylate-based compound (B) is a weight average molecular weight in terms of standard polystyrene molecular weight, and a high performance liquid chromatograph (manufactured by Waters, "ACQUITY APC system") has a column: ACQUITY. It is measured by using four APC XT 450 × 1, ACQUITY APC XT 200 × 1, and ACQUITY APC XT 45 × 2 in series.

  The viscosity of the urethane (meth) acrylate 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 out of 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 preferably 20 to 100 parts by weight, more preferably 25 to 90 parts by weight, based on 100 parts by weight of the acrylic resin (A). Parts, particularly preferably 30 to 80 parts by weight. If the content of the urethane (meth) acrylate compound (B) is too small, the peeling property after irradiation with active energy rays tends to decrease, and if it is too large, cracks occur in the adhesive layer after irradiation with active energy rays. Tends to be easier.

[Isocyanate crosslinking agent (C)]
In the present invention, an isocyanate cross-linking agent (C) is used as a cross-linking agent. Among them, an isocyanate cross-linking agent having a specific structure is excellent in adhesive strength and heat resistance before irradiation with active energy rays. There is a remarkable effect.

  The isocyanate-based crosslinking agent (C) used in the present invention is characterized by being an alicyclic or aromatic polyvalent isocyanate (c1) having at least one isocyanate group bonded to primary carbon.

  Examples of the alicyclic or aromatic polyvalent isocyanate (c1) having at least one isocyanate group bonded to the primary carbon include hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate and norbornene. Alicyclic polyvalent isocyanate such as diisocyanate, xylylene diisocyanate, aromatic polyvalent isocyanate such as tetramethylxylylene diisocyanate, or these alicyclic polyvalent isocyanate or aromatic polyvalent isocyanate and trimethylolpropane An adduct with a polyol compound such as, or an isocyanurate body or a multimer compound of these alicyclic polyvalent isocyanates or aromatic polyvalent isocyanates, allophanate type polyisocyanate, Yuretto polyisocyanate, water dispersible polyisocyanate, and the like. These alicyclic polyvalent isocyanates or aromatic polyvalent isocyanates (c1) can be used alone or in combination of two or more.

  Among the above, when it is a pressure-sensitive adhesive layer, from the viewpoint of excellent adhesive strength and heat resistance before irradiation with active energy rays, derivatives of xylylene diisocyanate are preferable, and among others, adhesive strength before irradiation with active energy rays is good. The trimethylolpropane adduct of xylylene diisocyanate is particularly preferable because it is excellent in heat resistance and is excellent in peelability (contamination resistance and slight adhesiveness) after irradiation with active energy rays even after heating.

The content of the isocyanate cross-linking agent (C) is usually 0.01 to 15 parts by weight, preferably 0.1 to 10 parts by weight, and more preferably 100 parts by weight of the acrylic resin (A). Is 0.2 to 5 parts by weight. When the amount of the isocyanate cross-linking agent (C) is too small, the cohesive force of the pressure-sensitive adhesive tends to decrease, which may cause adhesive residue. There is a tendency for floating.
In the present invention, as the isocyanate cross-linking agent (C), a cross-linking agent other than the alicyclic or aromatic polyvalent isocyanate (c1) is used as long as it does not impair the object of the present invention, for example, an acrylic-based cross-linking agent. The resin (A) may be used in an amount of 15 parts by weight or less, preferably 10 parts by weight or less, based on 100 parts by weight.

[Photopolymerizable initiator (D)]
The photopolymerizable initiator (D) may be any one that generates a radical by the action of light, and examples thereof include diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, and benzyl. Dimethyl ketal, 4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone, 1-hydroxycyclohexyl phenyl ketone, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy- 2-Methyl-1-propan-1-one, 2-methyl-2-morpholino (4-thiomethylphenyl) propan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone , 2- (dimethylamino) -2-[(4-methylphenyl) methyl] -1- [4- (4-morpholinyl) Acetophenones such as phenyl] -1-butanone, 2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl] propanone oligomer; benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, Benzoins such as benzoin isobutyl ether; benzophenone, methyl o-benzoylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4′-methyl-diphenyl sulfide, 3,3 ′, 4,4′-tetra (tert-butylperoxide) (Oxycarbonyl) benzophenone, 2,4,6-trimethylbenzophenone, 4-benzoyl-N, N-dimethyl-N- [2- (1-oxo-2-propenyloxy) ethyl] benzenemethanaminium bromide, (4- Benzoyl benz ) Benzophenones such as trimethylammonium 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-one thioxanthones such as mesochloride; 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2 , 4,4-trimethyl-pentylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, and other acylphosphine oxides; and the like. Among them, preferably, acetophenones, especially 2- (dimethylamino) -2-[(4-methylphenyl) methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone and thioxanthones, It is especially 2,4,6-trimethylbenzoyl-diphenylphosphine oxide.
In addition, these photopolymerizable initiators (D) can be used alone or in combination of two or more kinds.

  Moreover, as an auxiliary agent of these photopolymerizable initiators (D), for example, triethanolamine, triisopropanolamine, 4,4′-dimethylaminobenzophenone (Michler's ketone), 4,4′-diethylaminobenzophenone, 2-dimethylamino Ethylbenzoic acid, ethyl 4-dimethylaminobenzoate, (n-butoxy) ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, 2-ethylhexyl 4-dimethylaminobenzoate, 2,4-diethylthioxane Son, 2,4-diisopropylthioxanthone and the like can also be used in combination. These auxiliaries can be used alone or in combination of two or more.

The content of the photopolymerizable initiator (D) is 0.1 to 20 parts by weight based on 100 parts by weight of the total of the acrylic resin (A) and the urethane (meth) acrylate compound (B). It is preferably 0.5 to 15 parts by weight, particularly preferably 1 to 10 parts by weight.
If the content of the photopolymerizable initiator (D) is too small, the releasability after irradiation with active energy rays tends to decrease, and if it is too large, the contamination of the work member tends to increase.

[Other ingredients]
The active energy ray-curable release-type pressure-sensitive adhesive composition of the present invention may further contain, for example, an ethylenically unsaturated compound in a range that does not impair the effects of the present invention, in terms of release properties after irradiation with active energy rays. Preferably, it further contains additives such as an antistatic agent, an antioxidant, a polymerization inhibitor, a plasticizer, a filler, a pigment, a diluent, an antiaging agent, an ultraviolet absorber, an ultraviolet stabilizer and a tackifying resin. May be. These additives may be used alone or in combination of two or more. In particular, the antioxidant is 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. In addition to the additive, a small amount of impurities and the like contained in the raw materials for manufacturing the constituent components of the active energy ray-curable release type pressure-sensitive adhesive composition may be contained.

  Thus, by mixing the acrylic resin (A), the urethane (meth) acrylate compound (B), the isocyanate cross-linking agent (C), the photopolymerizable initiator (D) and, if necessary, other 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 cross-linked by the above-mentioned isocyanate cross-linking agent (C) and exhibits the performance as a pressure-sensitive adhesive. The (meth) acrylate compound (B) is polymerized to cure the pressure-sensitive adhesive, and the adhesive strength is reduced, whereby the peelability is exhibited.

The active energy ray-curable release-type pressure-sensitive adhesive composition of the present invention usually temporarily protects the surface when processing a processed member such as an electronic substrate, a semiconductor wafer, a glass processed product, a metal plate or a plastic plate. It is preferably used as a pressure-sensitive adhesive layer of a peelable pressure-sensitive adhesive sheet.
Hereinafter, the peelable pressure-sensitive adhesive sheet will be described.

  The release-type pressure-sensitive adhesive sheet usually has a substrate sheet, a pressure-sensitive adhesive layer made of the active energy ray-curable release-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 directly applied to the release film or the base material sheet as it is or after the concentration thereof is adjusted with an appropriate organic solvent. Work. Then, for example, it is dried by heat treatment or the like at 80 to 105 ° C. for 0.5 to 10 minutes and attached to a base material sheet or a release film to obtain a peelable pressure-sensitive adhesive sheet. Further, aging may be further performed after drying in order to balance the adhesive physical properties.

  Examples of the base sheet include polyester resins such as polyethylene naphthalate, polyethylene terephthalate, polybutylene terephthalate and polyethylene terephthalate / isophthalate copolymers; polyolefin resins such as polyethylene, polypropylene and polymethylpentene; polyvinyl fluoride. , Polyvinylidene fluoride, polyfluorinated ethylene resins such as polyfluorinated ethylene; polyamides such as nylon 6, nylon 6,6; polyvinyl chloride, polyvinyl chloride / vinyl acetate copolymers, ethylene-vinyl acetate copolymers, ethylene- Vinyl polymers such as vinyl alcohol copolymer, polyvinyl alcohol and vinylon; cellulose resins such as cellulose triacetate and cellophane; polymethylmethacrylate, polyethylmethacrylate, polyacrylic acid Acrylic resin such as chill and polybutyl acrylate; polystyrene; polycarbonate; polyarylate; a sheet made of at least one synthetic resin selected from the group consisting of polyimide, aluminum, copper, iron metal foil, fine paper, Examples include paper such as glassine paper, woven fabric and non-woven fabric made of glass fiber, natural fiber, synthetic fiber and the like. These base material sheets can be used as a single-layer body or a multi-layer body 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 exemplified as the above-mentioned base material sheet, paper, woven fabric, non-woven fabric and the like subjected to release treatment can be used.

  Further, 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, for example, roll coating, die coating, gravure coating, comma coating. , Screen printing and the like.

  The thickness of the pressure-sensitive adhesive layer of the release-type pressure-sensitive adhesive sheet is usually preferably 10 to 200 μm, and more preferably 15 to 100 μm.

  As the active energy rays, light rays such as far-ultraviolet rays, ultraviolet rays, near-ultraviolet rays, infrared rays, etc., electromagnetic waves such as X-rays, γ-rays, electron rays, proton rays, neutron rays, etc. can usually be used, but curing speed, irradiation Ultraviolet rays are preferred because of the availability of the device and the price.

Integrated irradiation dose in the case of irradiating the ultraviolet radiation is typically 50~3,000mJ / cm ^2, preferably 100~1,000mJ / cm ^2. The irradiation time may vary 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 it is usually several seconds, and in some cases, may be a fraction of a second.

The adhesive force of the release-type pressure-sensitive adhesive sheet varies depending on the type of the base sheet, the type of the member to be processed, etc., but is preferably 5.5 N / 25 mm or more before irradiation with active energy rays, and further 6.0 N / 25 mm. The above is preferable. The upper limit of the adhesive force before irradiation with active energy rays is usually 100 N / 25 mm.
The adhesive strength after irradiation with active energy rays is preferably 0.7 N / 25 mm or less, more preferably 0.65 N / 25 mm or less.

  According to the active energy ray-curable release-type pressure-sensitive adhesive composition of the present invention, for example, the release-type pressure-sensitive adhesive sheet using the same as the pressure-sensitive adhesive is bonded to the workpiece and the surface of the workpiece is temporarily protected. After that, by irradiating with active energy rays as necessary, the pressure-sensitive adhesive is cured and its adhesive force is reduced, and it can be easily peeled 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 thereof is not exceeded. In the following, "%" and "parts" mean weight basis.

<Preparation of acrylic resin (A) solution>
[Acrylic resin (A-1)]
In a reactor equipped with a temperature controller, a thermometer, a stirrer, a dropping funnel and a reflux condenser, 29 parts of ethyl acetate was charged, and the temperature was raised with stirring. As a polymerization component, 58.8 parts of n-butyl acrylate, 40 parts of methyl acrylate, 1 part of 2-hydroxyethyl acrylate, 0.2 part of dimethylaminoethyl acrylate, and 0.037 part of azobisisobutyronitrile (AIBN) as a polymerization catalyst. Was mixed and dissolved, and the mixture was added dropwise over 2 hours, and the mixture was reacted under reflux. Then, 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, and 8 hours after the start of the reaction, 87.5 parts of ethyl acetate and 101 parts of toluene were added to carry out the reaction. After the completion, an acrylic resin (A-1) solution [weight average molecular weight 480,000, glass transition temperature -33.7 ° C, resin content 37.3%, viscosity 7,200 mPa · s (25 ° C)] was obtained.

[Acrylic resin (A-2)]
Acrylic resin (A-1) except that 59 parts of n-butyl acrylate, 40 parts of methyl acrylate, and 1 part of 2-hydroxyethyl acrylate were used as copolymerization components in the acrylic resin (A-1). Acrylic resin (A-2) solution [weight average molecular weight 720,000, glass transition temperature -33.8 ° C, resin content 36.5%, viscosity 8,600 mPa · s (25 ° C)] was obtained in the same manner as in. .

The urethane (meth) acrylic compound (B) was prepared as follows.
<Preparation of urethane (meth) acrylate compound (B)>
[Urethane acrylate (B1-1)]
A four-necked flask equipped with a temperature controller, a thermometer, a stirrer, a water-cooled condenser, and a nitrogen gas blowing port, 6.6 parts of isophorone diisocyanate, a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (hydroxyl value 48 mgKOH / G) 93.4 parts, 2,6-di-tert-butylcresol 0.06 parts as a polymerization inhibitor, and dibutyltin dilaurate 0.02 parts as a reaction catalyst were charged and reacted at 60 ° C. The reaction was terminated when the content became 0.3% or less, and a urethane acrylate (B1-1) (10 ethylenically unsaturated groups, weight average molecular weight 2,000) mixture was obtained.

  In addition, the following components were prepared.

[Isocyanate crosslinking agent (C)]
Isocyanate cross-linking agent (C-1): trimethylolpropane adduct of xylene diisocyanate (Mitsui Chemicals: Takenate D-110N)
Isocyanate cross-linking agent (C-2): trimethylolpropane adduct of isophorone diisocyanate (Mitsui Chemicals Inc .: Takenate D-140N)
Isocyanate-based cross-linking agent (C'-1): trimethylolpropane adduct of tolylene diisocyanate (Mitsui Chemicals: Takenate D-101E)
Isocyanate cross-linking agent (C′-2): isocyanurate body of tolylene diisocyanate (manufactured by Mitsui Chemicals: Takenate D-204EA)

[Photopolymerizable initiator (D)]
Photopolymerizable initiator (D-1): 2- (dimethylamino) -2-[(4-methylphenyl) methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone (IGM Resin) (Manufactured by: OMNIRAD379)

<Example 1>
[Preparation of adhesive composition]
The resin content of the acrylic resin (A-1) solution obtained above was adjusted to 40%, and 100 parts of the resin solution (40 parts of resin content), 20 parts of urethane acrylate (B1-1), and an isocyanate-based crosslinking agent. (C-1) 0.72 part (0.78 equivalent to the hydroxyl group of the acrylic resin (A)), photopolymerizable initiator (D-1) 0.6 part, and ethyl acetate 30 parts as a diluting solvent By mixing, an active energy ray-curable release type pressure-sensitive adhesive composition was obtained.

[Preparation of release type adhesive sheet]
After applying the obtained active energy ray-curable release type pressure-sensitive adhesive composition as a substrate sheet onto an easily adhesive polyethylene terephthalate film (film thickness 38 μm) (“T60 Lumirror” manufactured by Toray Industries, Inc.), After being dried at 100 ° C. for 2 minutes, it is attached to a release film (“SP-PET 3801-BU” manufactured by Mitsui Chemicals Tohcello) and aged for 7 days at 40 ° C. The thickness of the agent layer was 25 μm).
The following evaluations were carried out using the obtained release-type pressure-sensitive adhesive sheet.

[Adhesive strength: before irradiation with active energy rays]
A 25 mm × 100 mm test piece was prepared from the release type pressure-sensitive adhesive sheet obtained above, the release film was peeled off, and the stainless steel plate (SUS304BA plate) had a weight of 2 kg in an atmosphere of 23 ° C. and a relative humidity of 50%. The rubber roller of (1) was reciprocated two times to apply pressure, and after leaving for 30 minutes in the same atmosphere, the 180-degree peel strength (N / 25 mm) was measured at a peel speed of 300 mm / min. The evaluation criteria are as follows.
(Evaluation criteria)
◯: 6.0 N / 25 mm or more Δ: 5.5 N / 25 mm or more, less than 6.0 N / 25 mm × ... less than 5.5 N / 25 mm

[Adhesive strength: After heating and irradiation with active energy rays]
A 25 mm × 100 mm test piece was prepared from the release type pressure-sensitive adhesive sheet obtained above, the release film was peeled off, and the stainless steel plate (SUS304BA plate) had a weight of 2 kg in an atmosphere of 23 ° C. and a relative humidity of 50%. The rubber roller of No. 2 was reciprocated twice for pressure application, and then heat treatment was performed at 150 ° C. for 1 hour. The stainless steel plate to which the peelable pressure-sensitive adhesive sheet after the heat treatment was attached was left for 30 minutes in an atmosphere of 23 ° C. and a relative humidity of 50%, and then a high pressure mercury lamp of 80 W was used to measure 5.1 m from a height of 18 cm. Ultraviolet irradiation (cumulative irradiation amount 180 mJ / cm ² ) was performed at a conveyor speed of / min. Further, after leaving it for 30 minutes in an atmosphere of 23 ° C. and a relative humidity of 50%, the 180-degree peel strength (N / 25 mm) was measured at a peel speed of 300 mm / min. The evaluation criteria are as follows.
(Evaluation criteria)
○: 0.65 N / 25 mm or less △: 0.65 N / 25 mm or more, 0.7 N / 25 mm or less × ... 0.7 N / 25 mm or more, or adhesive residue

[Stain resistance: After heating and irradiation with active energy rays]
The release-type pressure-sensitive adhesive sheet obtained above was attached to the surface of a 4-inch square stainless steel plate (SUS304BA plate) on which no foreign matter was attached, and then heat treatment was performed at 150 ° C. for 1 hour. After the heat treatment, the stainless steel plate to which the release-type pressure-sensitive adhesive sheet was attached was allowed to stand in an atmosphere of 23 ° C. and relative humidity of 65% for 1 hour, and then from a height of 18 cm to 5. Ultraviolet irradiation (total irradiation amount 180 mJ / cm ² ) was performed at a conveyor speed of 1 m / min. Then, the peelable pressure-sensitive adhesive sheet was peeled from the surface of the stainless steel plate, and the adhesive residue was visually confirmed on the peeled stainless steel plate to evaluate the stain resistance. The evaluation criteria are as follows.
(Evaluation criteria)
○ ・ ・ ・ No adhesive residue △ ・ ・ ・ Partial adhesive residue × ・ ・ ・ Overall adhesive residue

<Example 2>
An active energy ray-curable release type pressure-sensitive adhesive composition was obtained in the same manner as in Example 1, except that the acrylic resin (A-2) solution was blended in place of the acrylic resin (A-1) solution. The same evaluation as in 1 was performed.

<Example 3>
In Example 1, an acrylic resin (A-2) solution was blended instead of the acrylic resin (A-1) solution, and an isocyanate cross-linking agent (C-2) was used instead of the isocyanate cross-linking agent (C-1). Was added in the same manner as in Example 1 except that 0.8 part (0.78 equivalent to the hydroxyl group of the acrylic resin (A)) was added. An evaluation was made.

<Comparative Example 1>
In Example 1, 0.64 parts (0.78 equivalents relative to the hydroxyl group of the acrylic resin (A)) of the isocyanate crosslinking agent (C′-1) was used instead of the isocyanate crosslinking agent (C-1). An active energy ray-curable release type pressure-sensitive adhesive composition was obtained in the same manner except that it was blended, and the same evaluation as in Example 1 was performed.

<Comparative example 2>
In Example 1, the acrylic resin (A-1) solution was mixed with the acrylic resin (A-2) solution, and the isocyanate cross-linking agent (C-1) was replaced with the isocyanate cross-linking agent (C′-). An active energy ray-curable release pressure-sensitive adhesive composition was obtained in the same manner as in Example 1 except that 0.64 part of (1) was added (0.78 equivalent to the hydroxyl group of the acrylic resin (A)). Similar evaluation was performed.

<Comparative example 3>
In Example 1, 0.76 parts (0.78 equivalent to the hydroxyl group of the acrylic resin (A)) of the isocyanate crosslinking agent (C′-2) was used instead of the isocyanate crosslinking agent (C-1). An active energy ray-curable release type pressure-sensitive adhesive composition was obtained in the same manner as in Example 1 except that the compounding was performed, and the same evaluation as in Example 1 was performed.

  The evaluation results of Examples and Comparative Examples are shown in Table 1 below.

  As can be seen from Table 1 above, the active energy ray-curable release-type pressure-sensitive adhesive compositions of Examples 1 to 3 were excellent in adhesive strength before irradiation with active energy rays, and also exhibited active energy rays after heating at 150 ° C. for 1 hour. The peelability when irradiated was also excellent. In particular, Examples 1 and 2 in which the isocyanate-based cross-linking agent (C) is a trimethylolpropane adduct of xylylene diisocyanate are excellent in adhesive force before irradiation with active energy rays and also excellent in releasability after heating. there were.

  On the other hand, Comparative Examples 1 and 2 which do not contain the specific isocyanate cross-linking agent (C) have excellent adhesive strength before irradiation with active energy rays, but even if they are irradiated with active energy rays after heating, In comparison, the adhesive strength did not decrease. Further, Comparative Example 3 containing no specific isocyanate cross-linking agent (C) was inferior in stain resistance.

  The active energy ray-curable release type pressure-sensitive adhesive composition of the present invention is preferably used for a temporary surface protection pressure-sensitive adhesive film when processing an electronic substrate, a semiconductor wafer, a glass processed product, a metal plate, a plastic plate or the like. You can

Claims (7)

An active energy ray-curable peelable pressure-sensitive adhesive composition containing an acrylic resin (A), a urethane (meth) acrylate compound (B), an isocyanate crosslinking agent (C) and a photopolymerizable initiator (D). hand,
The above-mentioned isocyanate-based cross-linking agent (C) is an alicyclic or aromatic polyvalent isocyanate (c1) having at least one isocyanate group bonded to primary carbon, and active energy ray-curable release -Type adhesive composition.   The active energy ray-curable release type pressure-sensitive adhesive composition according to claim 1, wherein the alicyclic or aromatic polyvalent isocyanate (c1) is a derivative of xylylene diisocyanate.   The active energy ray-curable peelable pressure-sensitive adhesive composition according to claim 1 or 2, wherein the alicyclic or aromatic polyvalent isocyanate (c1) is an adduct of a polyol compound.   Content of the said isocyanate type crosslinking agent (C) is 0.1-10 weight part with respect to 100 weight part of acrylic resin (A), The any one of the Claims 1-3 characterized by the above-mentioned. The active energy ray-curable peelable pressure-sensitive adhesive composition described.   The glass transition temperature (Tg) of the acrylic resin (A) is −60 to 0 ° C. 5. The active energy ray-curable peelable pressure-sensitive adhesive composition according to any one of claims 1 to 4, wherein object.   6. 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 peelable pressure-sensitive adhesive composition according to any one of claims.   The peelable pressure-sensitive adhesive sheet, wherein the active energy ray-curable peelable pressure-sensitive adhesive composition according to any one of claims 1 to 6 has a pressure-sensitive adhesive layer cross-linked with an isocyanate cross-linking agent (C). .