WO2020049829A1 - Pressure-sensitive adhesive composition and pressure-sensitive adhesive sheet - Google Patents

Abstract

A pressure-sensitive adhesive composition comprising a resin represented by formula (1-1) and a photopolymerization initiator. R¹ to R⁴ are each -H or -CH₃; R⁵ is a C_1-16 alkyl group; R⁶ is an alicyclic hydrocarbon group or an aromatic hydrocarbon group; R⁷ is -H or –(CH₂)_j-COOH (wherein j is 1 or 2); and R⁸ is a specific group.

Description

Pressure-sensitive adhesive composition and pressure-sensitive adhesive sheet

The present invention relates to a pressure-sensitive adhesive composition and a pressure-sensitive adhesive sheet.
This application claims priority based on Japanese Patent Application No. 2018-164843 filed on Sep. 3, 2018 in Japan, the contents of which are incorporated herein by reference.

Conventionally, various adhesive sheets have been used in a semiconductor manufacturing process and the like. Specifically, there are a protective sheet for protecting the wafer in the back grinding process of the semiconductor wafer and a fixing sheet used in the dicing process for cutting the semiconductor wafer into element pieces. These pressure-sensitive adhesive sheets are re-peelable pressure-sensitive adhesive sheets that are adhered to a semiconductor wafer as an adherend and peeled off from the adherend after a predetermined processing step is completed.
As the pressure-sensitive adhesive composition used for the pressure-sensitive adhesive layer of the removable pressure-sensitive adhesive sheet, a pressure-sensitive adhesive composition having an ethylenically unsaturated group in a molecule and containing a UV-curable resin is known.

Patent Literature 1 discloses that a (meth) acrylic polymer having two or more hydroxyl groups in a side chain is reacted with a compound having an isocyanato group in the presence of a first catalyst to form a (meth) acrylic polymer having a urethane bond. Forming a polymer, and reacting the (meth) acrylic polymer having a urethane bond with a compound having two or more isocyanato groups in one molecule in the presence of a second catalyst to form a pressure-sensitive adhesive layer. A method for producing a pressure-sensitive adhesive sheet is disclosed, which includes a forming step, wherein the first catalyst is a complex of at least one metal selected from zirconium, titanium, and aluminum, and the second catalyst is an amine-based catalyst.

Japanese Patent No. 5999685

The re-peelable pressure-sensitive adhesive sheet has sufficient adhesive strength to the adherend when performing the predetermined processing step, and can be easily peeled from the adherend after the predetermined processing step is completed (easy to be performed). It is required that the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet is not transferred to the adherend after peeling (no adhesive residue).
However, the conventional pressure-sensitive adhesive sheet has not satisfied all of the above conditions. In particular, when the pressure-sensitive adhesive sheet is stuck to the adherend, the adherend is processed at a high temperature of about 200 ° C., and then the adhesive sheet is peeled off by UV irradiation, it has been a problem that adhesive residue easily occurs. .

The present invention has been made in view of the above circumstances, and has a sufficient adhesive strength to an adherend by using it as a material for forming an adhesive layer of an adhesive sheet. To provide a pressure-sensitive adhesive composition capable of obtaining a pressure-sensitive adhesive sheet that can obtain excellent easy-peeling property and hardly generate adhesive residue even when the body is returned to room temperature, returned to room temperature, and peeled after UV irradiation. As an issue.
Another object of the present invention is to provide a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer containing the pressure-sensitive adhesive composition.

The present inventors have conducted intensive studies in order to solve the above problems. As a result, a carboxy group-containing resin (b) obtained by polymerizing the carboxy group-containing ethylenically unsaturated monomer (a) as an essential monomer component, and an alicyclic epoxy group-containing ethylenically unsaturated compound (c) It has been found that a pressure-sensitive adhesive composition containing, as essential components, a resin (A) obtained by an addition reaction with a photopolymerization initiator (B) may be used.

The pressure-sensitive adhesive composition containing the resin (A) and the photopolymerization initiator (B) has good heat resistance because the resin (A) has a structure derived from an alicyclic compound. Further, in the above-mentioned pressure-sensitive adhesive composition, the unsaturated bond in the resin (A) forms a three-dimensional crosslinked structure by irradiation with ultraviolet rays (UV), and is cured, so that the adhesive strength is changed. Specifically, before the adhesive composition is irradiated with UV, a sufficient adhesive force is obtained on the adherend, and after the UV irradiation, the adhesive force is reduced to obtain excellent easy peelability. And adhesive residue on the adherend after peeling can be sufficiently prevented.
The present inventors have conceived the present invention based on such findings. That is, the present invention relates to the following matters.

[1] A pressure-sensitive adhesive composition comprising a resin (A) represented by the following general formula (1-1) and a photopolymerization initiator (B).

(In the formula (1-1), k, l, m, and n indicate a molar composition ratio when k + 1 + m + n = 100. K is more than 0 to 92 or less. L is 0 to 50. is greater than 0 to 90 or less is ^{.k, l, .R 1 ~ R} 4 the sum of m is 65 ~ 95 .n is 5-35 is -H or -CH ₃ .R ⁵ carbon R ⁶ is an alicyclic hydrocarbon group having 3 to 30 carbon atoms or an aromatic hydrocarbon group having 6 to 20 carbon atoms, and R ⁷ is —H or — (CH ₂ ) _J —COOH (where j is 1 or 2), and R ⁸ is the above general formula (1-2) or (1-3). In 3), p and q are any one selected from 0, 1, and 2. s is 0 when p is 0, and 1 when p is 1 or 2. .R ⁹ is -H or -CH _3.)

[2] The pressure-sensitive adhesive composition according to [1], wherein the resin (A) has a weight average molecular weight of 200,000 to 1,000,000.
[3] The pressure-sensitive adhesive composition according to [1] or [2], wherein n in the formula (1-1) is 10 to 33.
[4] Any of [1] to [3], wherein k in the formula (1-1) is 45 to 90, l is 4 to 40, and m is 1 to 15. The pressure-sensitive adhesive composition as described in the above.

[5] The pressure-sensitive adhesive composition according to any one of [1] to [4], further comprising a crosslinking agent (C).
[6] The pressure-sensitive adhesive composition according to any one of [1] to [5], wherein the resin (A) has a glass transition temperature of −80 to 0 ° C.

[7] A sheet-like substrate, and an adhesive layer formed on the substrate, wherein the adhesive layer comprises the adhesive composition according to any one of [1] to [6]. A pressure-sensitive adhesive sheet comprising:

By using the pressure-sensitive adhesive composition of the present invention as a material for forming a pressure-sensitive adhesive layer of a pressure-sensitive adhesive sheet, the pressure-sensitive adhesive sheet has a sufficient adhesive strength to the adherend, and the adherend to which the pressure-sensitive adhesive sheet is attached is brought to a high temperature state. Even when the temperature is returned to room temperature and peeled after UV irradiation, excellent peelability is obtained, and a pressure-sensitive adhesive sheet with less adhesive residue is obtained.

Hereinafter, the pressure-sensitive adhesive composition and the pressure-sensitive adhesive sheet of the present invention will be described in detail. Note that the present invention is not limited to only the embodiments described below.
"Adhesive composition"
The pressure-sensitive adhesive composition of the present embodiment contains a resin (A) and a photopolymerization initiator (B).
(Resin (A))
The resin (A) contained in the pressure-sensitive adhesive composition of the present embodiment is a compound represented by the following general formula (1-1).

(In the formula (1-1), k, l, m, and n indicate a molar composition ratio when k + 1 + m + n = 100. K is more than 0 to 92 or less. L is 0 to 50. is greater than 0 to 90 or less is ^{.k, l, .R 1 ~ R} 4 the sum of m is 65 ~ 95 .n is 5-35 is -H or -CH ₃ .R ⁵ carbon R ⁶ is an alicyclic hydrocarbon group having 3 to 30 carbon atoms or an aromatic hydrocarbon group having 6 to 20 carbon atoms, and R ⁷ is —H or — (CH ₂ ) _J —COOH (where j is 1 or 2), and R ⁸ is the above general formula (1-2) or (1-3). In 3), p and q are any one selected from 0, 1, and 2. s is 0 when p is 0, and 1 when p is 1 or 2. .R ⁹ is -H or -CH _3.)

に お い て In the formula (1-1), k, l, m, and n indicate the molar composition ratio when k + 1 + m + n = 100. k is more than 0 to 92 or less. 1 is 0 to 50. m is more than 0 to 90 or less. The sum of k, l and m is 65-95. When the total of k, l, and m is 65 or more, the pressure-sensitive adhesive composition will have sufficient adhesion to an adherend before UV irradiation. The total of k, l, and m is preferably from 70 to 94, and more preferably from 80 to 90.

に お い て In the formula (1-1), the repeating unit enclosed by k (繰 り 返 し) (hereinafter referred to as “repeating unit k”) is an essential repeating unit. The repeating unit k contributes to the adhesive strength of the adhesive composition before UV irradiation. The number of repetitions k of the repeating unit k is more than 0 to 92 or less, preferably 45 to 90, and more preferably 60 to 88.

In the formula (1-1), there may be no repeating unit (hereinafter, referred to as “repeating unit l”) enclosed in parentheses (). In other words, the number of repetitions of the repeating unit 1 may be zero.
The repeating unit l contributes to the heat resistance of the pressure-sensitive adhesive composition. The number of repetitions 1 of the repeating unit 1 is from 0 to 50, preferably from 4 to 40, and more preferably from 5 to 30.

に お い て In the formula (1-1), the repeating unit enclosed by m () (hereinafter referred to as “repeating unit m”) is an essential repeating unit. The repeating unit m contributes to the adhesive strength and heat resistance of the adhesive composition before UV irradiation. When the pressure-sensitive adhesive composition includes a cross-linking agent having a functional group that reacts with a carboxy group, the repeating unit m reacts with the cross-linking agent to improve the cohesive strength of the pressure-sensitive adhesive composition. The repeating number m of the repeating unit m is more than 0 to 90 or less, preferably 1 to 15, and more preferably 1 to 5.

に お い て In the formula (1-1), the repeating unit (hereinafter referred to as “repeating unit n”) enclosed in () by n is an essential repeating unit. The repeating unit n contributes to the heat resistance of the pressure-sensitive adhesive composition. The number of repetitions n of the repeating unit n is 5 to 35, preferably 10 to 33, more preferably 10 to 20. When the repeating unit n is 35 or less, an unsaturated bond in the resin (A) forms a three-dimensional cross-linked structure by UV irradiation, and is cured, and the adhesive strength is reduced to an appropriate range. Become. When n is 5 or more, an effect of improving heat resistance due to the structure derived from the alicyclic compound can be obtained.

Due to the synergistic effect of the function contributed by each of these repeating units, the pressure-sensitive adhesive composition containing the resin (A) can achieve a better balance between the adhesive strength before ultraviolet (UV) irradiation and the adhesive strength after UV irradiation. Become. As a result, a sufficient pressure-sensitive adhesive force is obtained on the adherend before the UV irradiation, and the pressure-sensitive adhesive force is reduced after the UV irradiation, so that a more excellent peelability is obtained. In addition, the pressure-sensitive adhesive composition does not have an excessively high adhesive strength even when the temperature is returned to room temperature after being brought to a high temperature state before the UV irradiation. Glue residue on the body is less likely to occur.

In the repeating unit k, R ¹ is —H or —CH ₃ , preferably —H. R ⁵ is an alkyl group having 1 to 16 carbon atoms, preferably an alkyl group having 1 to 8 carbon atoms, and particularly preferably an alkyl group having 2, 4 or 8 carbon atoms.

The repeating unit k may be a plurality of types of repeating units having different R ¹ and R ⁵ . When the repeating unit k includes a plurality of types of repeating units, the molar composition ratio k of the repeating unit k indicates the total of the molar compositions of the plurality of types of repeating units. For example, when the repeating unit k includes repeating units A and B having different R ¹ and / or R ⁵ , the molar composition of the repeating unit A is 2 mol%, and the molar composition of the repeating unit B is 3 mol%. The molar composition ratio k of the number of repetitions k is “5” by summing the molar composition ratios of the repeating unit A and the repeating unit B.

In the repeating unit 1, R ² is —H or —CH ₃ , preferably —H. R ⁶ is an alicyclic hydrocarbon group having 3 to 30 carbon atoms or an aromatic hydrocarbon group having 6 to 20 carbon atoms, and an alicyclic hydrocarbon group having 6 to 20 carbon atoms or an aromatic group having 6 to 10 carbon atoms. Group hydrocarbon groups are preferred.
The repeating unit 1 may be a plurality of types of repeating units having different R ² and R ⁶ . When the repeating unit 1 includes a plurality of types of repeating units, the molar composition ratio 1 of the repeating unit 1 indicates the total of the molar compositions of the plurality of types of repeating units.

In the repeating unit m, R ³ is —H or —CH ₃ , preferably —H. R ⁷ is —H or — (CH ₂ ) _j —COOH (where j is 1 or 2), preferably —H.
The repeating unit m may be a plurality of types of repeating units having different R ³ and R ⁷ . In this case, the molar composition ratio m of the repeating unit m indicates the sum of the molar composition ratios of a plurality of types of repeating units.

In the repeating unit n, R ⁴ is —H or —CH ₃ , preferably —H. R ⁸ is the formula (1-2) or (1-3). Each of the groups represented by the formulas (1-2) and (1-3) includes a structure derived from an alicyclic compound and has a function of improving the heat resistance of the pressure-sensitive adhesive composition. In the formula (1-2) or (1-3), p and q are any one selected from 0, 1, and 2. s is 0 when p is 0, and 1 when p is 1 or 2. R ⁹ is —H or —CH ₃ .
The repeating unit n may be a plurality of types of repeating units having different R ⁴ and R ⁸ . In this case, the molar composition ratio n of the repeating unit n indicates the sum of the molar composition ratios of a plurality of types of repeating units.

The resin (A) represented by the formula (1-1) includes a random copolymer, a block copolymer, and an alternating copolymer composed of a repeating unit k, a repeating unit 1, a repeating unit m, and a repeating unit n. Any of these may be used. The resin (A) represented by the formula (1-1) may not contain the repeating unit 1 and may be a random copolymer or a block copolymer composed of the repeating unit k, the repeating unit m, and the repeating unit n. Or an alternating copolymer.

The weight average molecular weight of the resin (A) is preferably from 200,000 to 1,000,000, more preferably from 300,000 to 800,000. When the weight average molecular weight of the resin (A) is 200,000 or more, when the pressure-sensitive adhesive sheet having the pressure-sensitive adhesive layer containing the pressure-sensitive adhesive composition is peeled off after being adhered to the adherend, the pressure-sensitive adhesive layer is not adhered. Makes it more difficult to remain. When the weight average molecular weight of the resin (A) is 1,000,000 or less, the effect that the viscosity of the resin (A) does not become too high and the workability is good can be obtained. The weight average molecular weight of the resin (A) is a value measured by the method described in Examples.

The glass transition temperature (Tg) of the resin (A) is preferably from -80 to 0 ° C, more preferably from -60 to -10 ° C, and still more preferably from -50 to -10 ° C. When the glass transition temperature of the resin (A) is in the range of −80 ° C. to 0 ° C., the adhesive strength of the adhesive composition before UV irradiation becomes good. The Tg of the resin (A) is a value measured by the method described in Examples.
The acid value of the resin (A) is preferably more than 0 to 20 mgKOH / g, and more preferably 3 to 10 mgKOH / g. When the acid value of the resin (A) is in the range of more than 0 to 20 mgKOH / g, the adherend after heating (adhesive residue) is excellent and good. When the pressure-sensitive adhesive composition contains a crosslinking agent, when the acid value of the resin (A) is within the above range, the resin (A) reacts with the crosslinking agent, and the cohesive force of the pressure-sensitive adhesive composition is good. Become. The acid value of the resin (A) is a value measured by the method described in Examples.

(Production method of resin (A))
The resin (A) contained in the pressure-sensitive adhesive composition of the present embodiment can be produced, for example, by the following method.
First, a raw material monomer containing a carboxy group-containing ethylenically unsaturated monomer (a) and an ethylenically unsaturated monomer (d) is polymerized to produce a carboxy group-containing resin (b). Here, the ethylenically unsaturated monomer (d) may include a monomer that forms a repeating unit k after polymerization and a monomer that forms a skeleton of the repeating unit 1 after polymerization.
Next, a resin (A) is produced by an addition reaction between the carboxy group-containing resin (b) and the specific alicyclic epoxy group-containing ethylenically unsaturated compound (c).

(Carboxy group-containing ethylenically unsaturated monomer (a))
The carboxy group-containing ethylenically unsaturated monomer (a) used when producing the carboxy group-containing resin (b) is a monomer that forms a skeleton of a repeating unit m by polymerization. The carboxy group-containing ethylenically unsaturated monomer (a) has one carboxy group.
Examples of the carboxy group-containing ethylenically unsaturated monomer (a) include (meth) acrylic acid, β-carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, and the like.
Among them, (meth) acrylic acid and / or β-carboxyethyl (meth) acrylate are preferably used as the carboxy group-containing ethylenically unsaturated monomer (a) from the viewpoint of reactivity.

中 で (Meth) acryl in this specification means “acryl” or “methacryl”. (Meth) acrylate means “acrylate” or “methacrylate”.

(Carboxy group-containing resin (b))
The carboxy group-containing resin (b) comprises a carboxy group-containing ethylenically unsaturated monomer (a) and an ethylenically unsaturated monomer copolymerizable with the carboxy group-containing ethylenically unsaturated monomer (a) ( and d) is obtained by copolymerizing a raw material monomer containing at least
The carboxy group-containing resin (b) is a component serving as a skeleton of the resin (A) represented by the formula (1-1). The repeating unit k, the repeating unit 1 and the repeating unit m are all repeating units derived from the carboxy group-containing resin (b).

１ As the ethylenically unsaturated monomer (d), one or more monomers that form a skeleton of the repeating unit k by polymerization are used. As the ethylenically unsaturated monomer (d), one or more monomers that form a skeleton of the repeating unit 1 by polymerization together with a monomer that forms a skeleton of the repeating unit k by polymerization are used. Is also good.

The ethylenically unsaturated monomer (d), which forms a skeleton of the repeating unit k by polymerization, is an alkyl (meth) acrylate having 1 to 16 carbon atoms, and from the viewpoint of adjusting the peel strength of the pressure-sensitive adhesive composition. It preferably contains an alkyl (meth) acrylate having 2 to 16 carbon atoms, and more preferably contains an alkyl (meth) acrylate having 4 to 12 carbon atoms. Specifically, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, tert-butyl (meth) acrylate, isobutyl (meth) acrylate, 2-ethylhexyl (Meth) acrylate, isodecyl (meth) acrylate, n-hexyl (meth) acrylate, isooctyl (meth) acrylate, lauryl (meth) acrylate and the like can be mentioned. Of these, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and isooctyl (meth) acrylate are preferred.

Examples of the ethylenically unsaturated monomer (d) which forms a skeleton of a repeating unit 1 by polymerization include a (meth) acrylate having a cyclic alkyl group having 3 to 30 carbon atoms and an aromatic monomer having 6 to 20 carbon atoms. Group-containing (meth) acrylates and the like.

Examples of the cyclic alkyl group-containing (meth) acrylate having 3 to 30 carbon atoms used as the ethylenically unsaturated monomer (d) which forms a skeleton of the repeating unit 1 by polymerization include cyclohexyl (meth) acrylate, Norbornyl (meth) acrylate, isobornyl (meth) acrylate, norbornanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentanyloxy Ethyl (meth) acrylate, tricyclodecane dimethylol di (meth) acrylate and the like can be mentioned. Among these, it is particularly preferable to use isobornyl (meth) acrylate. When the cyclic alkyl (meth) acrylate is contained in the raw material monomer of the carboxy group-containing resin (b), the pressure-sensitive adhesive composition containing the resin (A) produced using the carboxy group-containing resin (b) Good heat resistance.

Examples of the (meth) acrylate containing an aromatic group having 6 to 20 carbon atoms, which is used as the ethylenically unsaturated monomer (d) which forms a skeleton of a repeating unit 1 by polymerization, include benzyl (meth) acrylate and phenoxyethyl. (Meth) acrylate, phenoxy polyethylene glycol (meth) acrylate, phenoxypropyl (meth) acrylate, phenoxy polypropylene glycol (meth) acrylate, and the like. Among these, it is particularly preferable to use benzyl (meth) acrylate. When an aromatic group-containing (meth) acrylate is contained in the raw material monomer of the carboxy group-containing resin (b), the pressure-sensitive adhesive composition containing the resin (A) produced using the carboxy group-containing resin (b) The heat resistance of the material becomes good.

The raw material monomers of the carboxy group-containing resin (b) include not only the above-mentioned carboxy group-containing ethylenically unsaturated monomer (a) and the above-mentioned ethylenically unsaturated monomer (d), but also A monomer copolymerizable with the carboxy group-containing ethylenically unsaturated monomer (a) other than the ethylenically unsaturated monomer (d) may be contained.

Other than the above ethylenically unsaturated monomer (d), the ethylenically unsaturated monomer copolymerizable with the carboxy group-containing ethylenically unsaturated monomer (a) includes alkoxyalkyl (meth) acrylate, Alkoxy (poly) alkylene glycol (meth) acrylate, hydroxy group-containing (meth) acrylate, fluorinated alkyl (meth) acrylate, dialkylaminoalkyl (meth) acrylate, (meth) acrylamide and the like.

Examples of the alkoxyalkyl (meth) acrylate include ethoxyethyl (meth) acrylate, methoxyethyl (meth) acrylate, butoxyethyl (meth) acrylate, 2-methoxyethoxyethyl (meth) acrylate, and 2-ethoxyethoxyethyl (meth). Acrylate and the like.

{Alkoxy (poly) alkylene glycol (meth) acrylates include, for example, methoxydiethylene glycol (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, and methoxydipropylene glycol (meth) acrylate.

Examples of the hydroxy group-containing (meth) acrylate include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 1,3-butanediol (meth) acrylate, Examples thereof include 1,4-butanediol (meth) acrylate, 1,6-hexanediol (meth) acrylate, and 3-methylpentanediol (meth) acrylate.

Examples of the fluorinated alkyl (meth) acrylate include octafluoropentyl (meth) acrylate.
Examples of the dialkylaminoalkyl (meth) acrylate include N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, and the like.

Examples of (meth) acrylamide include (meth) acrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-propyl (meth) acrylamide, N-isopropylacrylamide, and N-hexyl (meth) acrylamide , N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, (meth) acryloylmorpholine, diacetoneacrylamide and the like.

Specific examples other than the above of the monomer copolymerizable with the carboxy group-containing ethylenically unsaturated monomer (a) other than the ethylenically unsaturated monomer (d) include acrylonitrile, methacrylonitrile, styrene, α-methylstyrene, vinyl acetate, vinyl propionate, vinyl stearate, vinyl chloride, vinylidene chloride, alkyl vinyl ether, vinyl toluene, N-vinyl pyridine, N-vinyl pyrrolidone, dialkyl itaconate, dialkyl fumarate, allyl alcohol , Hydroxybutyl vinyl ether, hydroxyethyl vinyl ether, 4-hydroxymethylcyclohexylmethyl vinyl ether, triethylene glycol monovinyl ether or diethylene glycol monovinyl ether, methyl vinyl ketone, allyl Trimethyl ammonium chloride, dimethyl allyl vinyl ketone.

The method for producing the carboxy group-containing resin (b) is not particularly limited.
For example, a raw material monomer containing a carboxy group-containing ethylenically unsaturated monomer (a) and an ethylenically unsaturated monomer (d), which are constituents of the carboxy group-containing resin (b), is polymerized by known polymerization. It is obtained by copolymerizing according to the method.
Specifically, as a polymerization method, a solution polymerization method, an emulsion polymerization method, a bulk polymerization method, a suspension polymerization method, an alternating copolymerization method, or the like can be used. Among these polymerization methods, considering the addition reaction between the carboxy group-containing resin (b) obtained after the polymerization and the alicyclic epoxy group-containing ethylenically unsaturated compound (c), a solution is preferred in terms of ease of reaction. It is preferable to use a polymerization method.

When producing the carboxy group-containing resin (b) by the solution polymerization method, a radical polymerization initiator and / or a solvent are used as necessary.
The radical polymerization initiator is not particularly limited, and can be appropriately selected from known ones.
Examples of the radical polymerization initiator include 2,2′-azobis (isobutyronitrile), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), and 2,2′-azobis (2 , 4-Dimethylvaleronitrile), 2,2'-azobis (2-methylbutyronitrile), 1,1'-azobis (cyclohexane-1-carbonitrile), 2,2'-azobis (2,4,4 Azo-based polymerization initiators such as -trimethylpentane) and dimethyl-2,2'-azobis (2-methylpropionate); benzoyl peroxide, t-butyl hydroperoxide, di-t-butyl peroxide, t- Butylperoxybenzoate, dicumyl peroxide, 1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane, 1,1-bis (t Oil-soluble polymerization initiators such as peroxide-based polymerization initiators such as (butylperoxy) cyclododecane are exemplified.

These radical polymerization initiators may be used alone or in combination of two or more.
The amount of the radical polymerization initiator to be used is preferably 0.01 to 5 parts by mass, and preferably 0.02 to 4 parts by mass, based on 100 parts by mass of the raw material monomer of the carboxy group-containing resin (b). Is more preferable, and the content is more preferably 0.03 to 3 parts by mass.

As a solvent for polymerization used when producing the carboxy group-containing resin (b), various general solvents can be used. Examples of the solvent include esters such as ethyl acetate, n-propyl acetate and n-butyl acetate; aromatic hydrocarbons such as toluene, xylene and benzene; and aliphatic hydrocarbons such as n-hexane and n-heptane. , Cyclohexane, alicyclic hydrocarbons such as methylcyclohexane, ketones such as methyl ethyl ketone and methyl isobutyl ketone, glycols such as ethylene glycol, propylene glycol, dipropylene glycol, methyl cellosolve, propylene glycol monomethyl ether, dipropylene glycol monomethyl Glycol ethers such as ether, and glycol esters such as ethylene glycol diacetate and propylene glycol monomethyl ether acetate.
These solvents may be used alone or in combination of two or more.

When producing the carboxy group-containing resin (b), the carboxy group-containing ethylenically unsaturated monomer (a), the ethylenically unsaturated monomer (d), and other The content of the carboxy group-containing ethylenically unsaturated monomer (a) in the raw material monomer containing the monomer is preferably 5 to 40% by mass, more preferably 7 to 30% by mass, 10 to 25% by mass is more preferred. By setting the content of the carboxy group-containing ethylenically unsaturated monomer (a) in the raw material monomer in the above range, the carboxy group-containing resin (b) and the alicyclic epoxy group-containing ethylenically unsaturated compound ( The adhesive strength before the UV irradiation of the adhesive layer obtained from the adhesive composition containing the resin (A) produced by the addition reaction with c) is improved.

(Alicyclic epoxy group-containing ethylenically unsaturated compound (c))
The alicyclic epoxy group-containing ethylenically unsaturated compound (c) is an ethylenically unsaturated group-containing compound having an alicyclic epoxy group and represented by the general formula (1-2) or the general formula (1-3). A compound that gives structure. The alicyclic epoxy group in the present embodiment refers to an epoxy group formed by bonding one oxygen to two adjacent carbon atoms on the ring of the alicyclic hydrocarbon compound.
The alicyclic epoxy group-containing ethylenically unsaturated compound (c) is represented by the following partial structural formula (1-2 ′) or (1- ′) in the repeating unit n of the photosensitive resin (A) represented by the formula (1-1). 3 '). The partial structural formula (1-2 ′) or (1-3 ′) in the repeating unit n in the formula (1-1) is a group derived from the alicyclic epoxy group-containing ethylenically unsaturated compound (c). .

(In the formulas (1-2 ′) and (1-3 ′), q is any one selected from 0, 1, and 2. R ⁹ is —H or —CH _3. )

Examples of the alicyclic epoxy group-containing ethylenically unsaturated compound (c) include compounds represented by the following formula (1) or (2).

(In the formula (1), R ⁹ is —H or —CH _3. Q is any one selected from 0, 1, and 2.)
(In the formula (2), R ⁹ is —H or —CH _3. Q is any one selected from 0, 1, and 2.)

In the formula (1), R ⁹ is —H or —CH ₃ . q is any one selected from 0, 1, and 2, and q is preferably 1.
In the formula (2), R ⁹ is —H or —CH ₃ . q is any one selected from 0, 1, and 2, and q is preferably 1.

The alicyclic epoxy group-containing ethylenically unsaturated compound (c) is preferably a compound represented by the formula (1), particularly preferably 3,4-epoxycyclohexylmethyl (meth) acrylate.
The alicyclic epoxy group-containing ethylenically unsaturated compound (c) may be used alone or in combination of two or more.

The resin (A) of the present embodiment is obtained by adding an alicyclic epoxy group of the alicyclic epoxy group-containing ethylenically unsaturated monomer (c) to the carboxy group of the carboxy group-containing resin (b). Can be manufactured.
The resin (A) is preferably 0.2 to 0.99 mol, more preferably 0.3 to 0.95 mol, and still more preferably 0.6 to 0.9 mol, per 1 mol of the carboxy group of the carboxy group-containing resin (b). It is preferable to produce the compound by subjecting 95 mol of an alicyclic epoxy group-containing ethylenically unsaturated compound (c) to an addition reaction. The pressure-sensitive adhesive composition containing the resin (A) obtained by using the carboxy group-containing resin (b) and the alicyclic epoxy group-containing ethylenically unsaturated compound (c) at the above ratio, before UV irradiation, Sufficient adhesiveness to the adherend is obtained, and the adhesive strength is reduced after UV irradiation, so that more excellent peelability is obtained. In addition, the pressure-sensitive adhesive composition has a low adhesive strength even when the temperature is returned to room temperature after being brought to a high temperature state before UV irradiation, and excellent peelability after UV irradiation is obtained, and the adherend after peeling is obtained. Glue residue can be more effectively prevented.

付 加 The temperature of the addition reaction in producing the resin (A) is preferably from 80 to 130 ° C, particularly preferably from 90 to 120 ° C. When the temperature of the addition reaction is 80 ° C. or higher, a sufficient reaction rate can be obtained. When the temperature of the addition reaction is 130 ° C. or lower, it is possible to prevent a double bond portion from being crosslinked by heat-induced radical polymerization, thereby preventing the formation of a gel.

A known catalyst can be used for the addition reaction in the production of the resin (A), if necessary. Examples of the catalyst include triethylamine, tributylamine, dimethylbenzylamine, 1,8-diazabicyclo [5,4,0] undec-7-ene, 1,5-diazabicyclo [4,3,0] non-5-ene Tertiary amines such as 1,4-diazabicyclo [2,2,2] octane, quaternary ammonium salts such as tetramethylammonium chloride, tetramethylammonium bromide and tetrabutylammonium bromide, alkylureas such as tetramethylurea, Alkylguanidines such as methylguanidine, triphenylphosphine, dimethylphenylphosphine, tricyclohexylphosphine, tributylphosphine, tris (4-methylphenyl) phosphine, tris (4-methoxyphenyl) phosphine, tris (2,6 Phosphine compounds such as dimethylphenyl) phosphine, tris (2,6-dimethoxyphenyl) phosphine, tris (2,4,6-trimethylphenyl) phosphine, and tris (2,4,6-trimethoxyphenyl) phosphine; .
As the catalyst for the addition reaction, among the above, it is preferable to use a phosphine compound from the viewpoint of reactivity.

The amount of the catalyst used in the addition reaction is 0.01 to 30 parts by mass based on 100 parts by mass of the total of the carboxy group-containing resin (b) and the alicyclic epoxy group-containing ethylenically unsaturated monomer (c). Is preferably 0.05 to 5 parts by mass, and most preferably 0.1 to 2 parts by mass.

Further, at the time of the addition reaction, a gas having a polymerization inhibiting effect may be introduced into the reaction system, or a polymerization inhibitor may be added. Gelation during the addition reaction can be prevented by introducing a gas having a polymerization inhibiting effect into the reaction system or adding a polymerization inhibitor.
Examples of the gas having a polymerization inhibiting effect include a gas containing oxygen that does not enter the explosion range of the substance in the system, for example, air.

Known polymerization inhibitors can be used, and are not particularly limited. For example, 4-methoxyphenol, hydroquinone, methoquinone, 2,6-di-t-butylphenol, 2,2′-methylenebis ( 4-methyl-6-t-butylphenol), phenothiazine and the like. One of these polymerization inhibitors may be used alone, or two or more thereof may be used in combination.

The amount of the polymerization inhibitor to be used is 0.005 to 5 parts by mass with respect to 100 parts by mass of the total of the carboxy group-containing resin (b) and the alicyclic epoxy group-containing ethylenically unsaturated monomer (c). Is preferably 0.03 to 3 parts by mass, and most preferably 0.05 to 1.5 parts by mass. If the amount of the polymerization inhibitor is too small, the polymerization inhibition effect may not be sufficient. On the other hand, if the amount of the polymerization inhibitor is too large, the exposure sensitivity of the resin (A) may decrease.
It is more preferable to use a gas having a polymerization inhibiting effect and a polymerization inhibitor in combination, since the amount of the polymerization inhibitor to be used can be reduced or the polymerization inhibiting effect can be increased.

(Photopolymerization initiator (B))
Examples of the photopolymerization initiator (B) contained in the pressure-sensitive adhesive composition include benzophenone, benzyl, benzoin, ω-bromoacetophenone, chloroacetone, acetophenone, 2,2-diethoxyacetophenone, and 2,2-dimethoxy-2. -Phenylacetophenone, p-dimethylaminoacetophenone, p-dimethylaminopropiophenone, 2-chlorobenzophenone, 4,4'-dichlorobenzophenone, 4,4'-bisdiethylaminobenzophenone, Michler's ketone, benzoin methyl ether, benzoin isobutyl ether, Benzoin-n-butyl ether, benzyl methyl ketal, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1- (4-isopropyl Nyl) -2-hydroxy-2-methylpropan-1-one, methylbenzoyl formate, 2,2-diethoxyacetophenone, 4-N, N'-dimethylacetophenone, 2-methyl-1- [4- (methylthio )]-Phenyl] -2-morpholinopropan-1-one and the like.

Examples of the photopolymerization initiator (B) include sulfide photopolymerization initiators such as diphenyl disulfide, dibenzyl disulfide, tetraethylthiuram disulfide, and tetramethylammonium monosulfide; 2,4,6-trimethylbenzoyldiphenylphosphine oxide; Acylphosphine oxides such as 2,6-trimethylbenzoylphenylethoxyphosphine oxide; quinone-based photopolymerization initiators such as benzoquinone and anthraquinone; sulfochloride-based photopolymerization initiators; thioxanthones such as thioxanthone, 2-chlorothioxanthone and 2-methylthioxanthone A system photopolymerization initiator or the like may be used.

Among these photopolymerization initiators (B), 1-hydroxycyclohexylphenyl ketone and / or 2,4,6-trimethylbenzoyldiphenylphosphine oxide may be used from the viewpoint of solubility in the pressure-sensitive adhesive composition. preferable.
The above photopolymerization initiators (B) may be used alone or in combination of two or more.

The photopolymerization initiator (B) contained in the pressure-sensitive adhesive composition is preferably 0.1 to 5.0 parts by mass, and more preferably 0.5 to 2.0 parts by mass based on 100 parts by mass of the resin (A). Is more preferable. When the content of the photopolymerization initiator (B) is 0.1 parts by mass or more based on 100 parts by mass of the resin (A), the pressure-sensitive adhesive composition is cured at a sufficiently high curing rate by UV irradiation, and the UV irradiation is performed. The adhesive strength of the adhesive composition after irradiation becomes sufficiently small, which is preferable. When the content of the photopolymerization initiator (B) is 5.0 parts by mass or less, when the pressure-sensitive adhesive sheet having the pressure-sensitive adhesive layer containing the pressure-sensitive adhesive composition is peeled off after being attached to the adherend, the pressure-sensitive adhesive is The agent layer hardly remains on the adherend. Further, even if the content of the photopolymerization initiator (B) exceeds 5.0 parts by mass, no effect corresponding to the content of the photopolymerization initiator (B) is obtained.

(Crosslinking agent (C))
The pressure-sensitive adhesive composition of the present embodiment may contain not only the resin (A) and the photopolymerization initiator (B) but also a crosslinking agent (C). By containing the cross-linking agent (C), a pressure-sensitive adhesive composition having a better balance between the pressure-sensitive adhesive strength before UV irradiation and the pressure-sensitive adhesive strength after UV irradiation is obtained.
The crosslinking agent (C) is not particularly limited, but is preferably a compound having two or more functional groups reactive with the hydroxyl group of the repeating unit n or the hydroxyl group of the repeating unit n and the carboxy group of the repeating unit m.

Examples of the crosslinking agent (C) include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, hydrogenated tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, diphenylmethane- 4,4-diisocyanate, isophorone diisocyanate, 1,3-bis (N, N'-diglycidylaminomethyl) cyclohexane, 1,3-bis (isocyanatomethyl) cyclohexane, isocyanurate of hexamethylene diisocyanate, tetramethylxylylene Diisocyanate, 1,5-naphthalene diisocyanate, tolylene diisocyanate adduct of trimethylolpropane, xylylene diisocyanate adduct of trimethylolpropane, triphenylmethane triisocyanate , Methylene bis (4-phenyl methane) isocyanate compounds such as triisocyanates,
Bisphenol A / epichlorohydrin type epoxy resin, N, N '-[1,3-phenylenebis (methylene)] bis [bis (oxiran-2-ylmethyl) amine], ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, Glycerin diglycidyl ether, glycerin triglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidylerythritol, diglycerol polyglycidyl ether, etc. Epoxy compound,
Tetramethylolmethane-tri-β-aziridinylpropionate, trimethylolpropane-tri-β-aziridinylpropionate, N, N′-diphenylmethane-4,4′-bis (1-aziridinecarboxamide) , Aziridine compounds such as N, N'-hexamethylene-1,6-bis (1-aziridinecarboxamide);
Melamine-based compounds such as hexamethoxymethylmelamine, hexaethoxymethylmelamine, hexapropoxymethylmelamine, hexaptoxymethylmelamine, hexapentyloxymethylmelamine, and hexahexyloxymethylmelamine are exemplified.

Among these, as the crosslinking agent (C), it is preferable to use an epoxy compound and / or an isocyanate compound because the reactivity with the resin (A) is good.
The above crosslinking agents (C) may be used alone or in combination of two or more.

The crosslinking agent (C) contained in the pressure-sensitive adhesive composition is preferably 0.05 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, based on 100 parts by mass of the resin (A). More preferably, it is 0.1 to 1.0 part by mass. When the content of the crosslinking agent (C) is at least 0.05 part by mass with respect to 100 parts by mass of the resin (A), a three-dimensional crosslinked structure is sufficiently formed in the pressure-sensitive adhesive composition. As a result, the adhesive strength of the adhesive composition after UV irradiation is sufficiently reduced, which is preferable. When the content of the crosslinking agent (C) is 10 parts by mass or less based on 100 parts by mass of the resin (A), the adhesive force of the pressure-sensitive adhesive composition before UV irradiation becomes good.

(Other ingredients)
The pressure-sensitive adhesive composition of the present embodiment may contain components other than the above-mentioned resin (A), photopolymerization initiator (B), and crosslinking agent (C), if necessary.
Other components include a tackifier, a solvent, various additives, and the like.

(Tackifier)
Conventionally known tackifiers can be used without particular limitation. Examples of the tackifier include terpene-based tackifier resins, phenol-based tackifier resins, rosin-based tackifier resins, aliphatic petroleum resins, aromatic petroleum resins, copolymer petroleum resins, and alicyclic petroleum resins. , A xylene resin, an epoxy-based tackifying resin, a polyamide-based tackifying resin, a ketone-based tackifying resin, an elastomer-based tackifying resin, and the like. These tackifiers may be used alone or in combination of two or more.

When the pressure-sensitive adhesive composition of the present embodiment contains a tackifier, the content is preferably 30 parts by mass or less, and more preferably 5 to 20 parts by mass with respect to 100 parts by mass of the resin (A). More preferred.

(solvent)
The solvent can be used for diluting the pressure-sensitive adhesive composition for the purpose of adjusting the viscosity of the pressure-sensitive adhesive composition when applying the pressure-sensitive adhesive composition.
As the solvent, for example, an organic solvent such as methyl ethyl ketone, methyl isobutyl ketone, acetone, ethyl acetate, n-propyl acetate, tetrahydrofuran, dioxane, cyclohexanone, n-hexane, toluene, xylene, n-propanol and isopropanol can be used. it can. These solvents may be used alone or in combination of two or more.

(Additive)
Additives include plasticizers, surface lubricants, leveling agents, softeners, antioxidants, antioxidants, light stabilizers, ultraviolet absorbers, polymerization inhibitors, light stabilizers such as benzotriazoles, phosphate esters And other flame retardants, antistatic agents such as surfactants and the like.

[Method for producing pressure-sensitive adhesive composition]
The pressure-sensitive adhesive composition of the present embodiment can be manufactured by a conventionally known method.
For example, the resin (A) and the photopolymerization initiator (B) described above are mixed with a crosslinking agent (C), a tackifier, a solvent, and various additives, which are contained as necessary, using a conventionally known method. Then, it can be produced by stirring.

The pressure-sensitive adhesive composition of the present embodiment is suitable as a material for forming a pressure-sensitive adhesive layer of a pressure-sensitive adhesive sheet. In particular, the pressure-sensitive adhesive composition of the present embodiment is preferable as a material for forming a pressure-sensitive adhesive layer of a removable pressure-sensitive adhesive sheet.
Since the pressure-sensitive adhesive composition of this embodiment contains the resin (A) represented by the formula (1-1) and the photopolymerization initiator (B), it is used as a material for forming a pressure-sensitive adhesive layer of a pressure-sensitive adhesive sheet. Thus, an adhesive sheet having a sufficient adhesive strength to the adherend is obtained. Moreover, even when the adherend to which the adhesive sheet is attached is heated to a high temperature and then returned to room temperature and peeled, the adhesive sheet provides excellent easy peelability after UV irradiation and hardly causes adhesive residue.

"Adhesive sheet"
The pressure-sensitive adhesive sheet of the present invention has a sheet-shaped substrate and a pressure-sensitive adhesive layer formed on the substrate.
It is preferable that a release sheet (separator) is provided on the surface of the pressure-sensitive adhesive layer opposite to the substrate. When a release sheet is provided on the pressure-sensitive adhesive layer, the pressure-sensitive adhesive layer can be protected by the release sheet until use. When a release sheet is provided on the pressure-sensitive adhesive layer, the operation of peeling the release sheet to expose the pressure-sensitive adhesive layer and pressing the pressure-sensitive adhesive layer (adhering surface) to the adherend can be efficiently performed. .
The pressure-sensitive adhesive sheet of this embodiment may be used as a pressure-sensitive adhesive tape formed into a shape according to the shape of the adherend by a punching method or the like. Further, the pressure-sensitive adhesive sheet of the present embodiment may be wound and cut to be used as a pressure-sensitive adhesive tape.

As the substrate, a known sheet material can be appropriately selected and used. It is preferable to use a resin sheet made of a transparent resin material as the base material.
Examples of the resin material include polyolefins such as polyethylene (PE) and polypropylene (PP); polyester sheets such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT) and polyethylene naphthalate; polyvinyl chloride (PVC); polyimide (PI) Polyphenylene sulfide (PPS); ethylene vinyl acetate (EVA); polytetrafluoroethylene (PTFE), and the like. Among these resin materials, it is preferable to use PE, PP, or PET because a sheet having appropriate flexibility can be obtained. As the resin material, only one kind may be used alone, or two or more kinds may be used in combination.

(4) When a resin sheet is used as the base material, the resin sheet may have a single-layer structure or a multilayer structure having two or more layers (for example, a three-layer structure). In the resin sheet having a multilayer structure, the resin material constituting each layer may be a resin material containing only one type or a resin material containing two or more types.

The thickness of the substrate can be appropriately selected according to the use of the pressure-sensitive adhesive sheet, the material of the substrate, and the like. When the pressure-sensitive adhesive sheet protects the wafer during the wafer dicing step and a resin sheet is used as the base material, the base material preferably has a thickness of, for example, 10 to 1000 μm, More preferably, it is 50 to 300 μm. When the thickness of the base material is 10 μm or more, the rigidity of the pressure-sensitive adhesive sheet becomes high (stiffness becomes high). Therefore, when the pressure-sensitive adhesive sheet is attached to or adhered to an adherend such as a wafer, the pressure-sensitive adhesive sheet tends to be less likely to wrinkle or float. In addition, when the thickness of the base material is 10 μm or more, the pressure-sensitive adhesive sheet attached to the adherend is easily peeled off from the adherend, and workability (handling property, handling) is improved. When the thickness of the base material is 1000 μm or less, it is possible to prevent the rigidity of the pressure-sensitive adhesive sheet from becoming too high (stiffness) and lowering the workability.

When a resin sheet is used as the substrate, a conventionally known general sheet forming method (for example, extrusion molding, T-die molding, inflation molding, or uniaxial or biaxial stretching molding) is appropriately adopted to form the substrate. Can be manufactured.

The surface of the substrate on the side in contact with the pressure-sensitive adhesive layer may be subjected to a surface treatment for improving the adhesion between the substrate and the pressure-sensitive adhesive layer.
Examples of the surface treatment include corona discharge treatment, acid treatment, ultraviolet irradiation treatment, plasma treatment, and application of a primer (primer).

The pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet of the present embodiment includes the above-described pressure-sensitive adhesive composition.
The thickness of the pressure-sensitive adhesive layer is preferably from 1 to 100 μm, more preferably from 2 to 80 μm, even more preferably from 5 to 50 μm. When the thickness of the pressure-sensitive adhesive layer is 1 μm or more, the uniformity of the thickness of the pressure-sensitive adhesive layer is improved. On the other hand, the thickness of the pressure-sensitive adhesive layer is preferably 100 μm or less, because the solvent can be easily removed even when the pressure-sensitive adhesive layer is formed using a solvent.

When a release sheet is provided on the surface of the pressure-sensitive adhesive layer opposite to the base material, a known sheet-like material can be appropriately selected and used as the release sheet. As the release sheet, the same as the above-described resin sheet used as the base material can be used.
The thickness of the release sheet can be appropriately selected according to the use of the pressure-sensitive adhesive sheet, the material of the release sheet, and the like. When a resin sheet is used as the release sheet, the thickness of the release sheet is preferably, for example, 5 to 300 μm, more preferably 10 to 200 μm, and further preferably 25 to 100 μm.

The release surface of the release sheet (the surface placed in contact with the pressure-sensitive adhesive layer) is subjected to a release treatment using a conventionally known release agent such as a silicone-based, long-chain alkyl-based, or fluorine-based release agent, if necessary. You may.

[Production method of adhesive sheet]
The pressure-sensitive adhesive sheet of the present embodiment can be manufactured, for example, by the following method.
First, a pressure-sensitive adhesive solution in which the above-described pressure-sensitive adhesive composition is dissolved or dispersed in a solvent is prepared. The above-mentioned pressure-sensitive adhesive composition may be used as a pressure-sensitive adhesive solution as it is.
Next, a pressure-sensitive adhesive solution is applied on the substrate, and dried by heating to form a pressure-sensitive adhesive layer. Thereafter, it is obtained by laminating a release sheet on the pressure-sensitive adhesive layer as necessary.
Further, as another method for producing the pressure-sensitive adhesive sheet of the present embodiment, the above-mentioned pressure-sensitive adhesive solution is applied onto a release sheet, and dried by heating to form a pressure-sensitive adhesive layer. After that, there is a method in which a release sheet having an adhesive layer is placed on a substrate with the surface on the adhesive layer side facing the substrate, and the adhesive layer is transferred (transferred) onto the substrate.

公 知 A known method can be used as a method of applying the above-mentioned pressure-sensitive adhesive solution on a base material (or on a release sheet). Specifically, a conventional coater, such as a gravure roll coater, a reverse roll coater, a kiss roll coater, a dip roll coater, a bar coater, a knife coater, a spray coater, a comma coater, a method of applying using a direct coater and the like. Can be

[Uses of adhesive sheet]
The pressure-sensitive adhesive sheet of the present embodiment can be used as a removable pressure-sensitive adhesive sheet. The pressure-sensitive adhesive sheet of the present embodiment can be used, for example, when manufacturing an electronic component. The adhesive sheet according to the present embodiment is, specifically, in each step of manufacturing an electronic component, after fixing an adherend, performing various processing steps, and then irradiating an ultraviolet ray (UV) with the adherend. Used for exfoliating and collecting body. Therefore, the pressure-sensitive adhesive sheet of this embodiment can be used as a back grinding tape, a dicing tape, or the like when processing a semiconductor wafer. Further, the pressure-sensitive adhesive sheet of the present embodiment can be suitably used as a support tape for a fragile member such as an ultra-thin glass substrate, a plastic film, or a easily warped member such as a flexible printed circuit board (FPC board). In particular, the pressure-sensitive adhesive sheet of the present embodiment is suitable as a dicing tape for protecting a wafer when performing a wafer dicing step.

When using the pressure-sensitive adhesive sheet of the present embodiment as a dicing tape for a wafer, the pressure-sensitive adhesive sheet is attached to a wafer on which a plurality of components are formed before performing a dicing step. Next, the wafer is cut and cut into individual parts (diced) to obtain element small pieces (chips). Then, UV is irradiated to the adhesive sheet stuck on each element piece. Thereby, UV is irradiated to the pressure-sensitive adhesive layer through the base material of the pressure-sensitive adhesive sheet, and the unsaturated bond in the pressure-sensitive adhesive forms a three-dimensional crosslinked structure and is cured. As a result, the adhesive strength of the adhesive layer decreases. Thereafter, the adhesive sheet is peeled off from each element piece.

As a light source used when performing UV irradiation on the pressure-sensitive adhesive sheet before peeling attached to the adherend, for example, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp carbon arc lamp, a xenon lamp, a metal halide lamp, a chemical lamp, a black lamp Light and the like.
UV dose to be irradiated to the adhesive sheet is preferably 50 ~ 3000mJ / cm ^2, more preferably 100 ~ 600mJ / cm ^2. When the amount of UV irradiation applied to the pressure-sensitive adhesive sheet is 50 mJ / cm ² or more, the pressure-sensitive adhesive layer is cured at a sufficiently high curing speed by UV irradiation, and the adhesive force of the pressure-sensitive adhesive layer after UV irradiation is sufficiently high. It is smaller and preferable. Even if the UV irradiation amount irradiating the pressure-sensitive adhesive sheet is 3000 mJ / cm ² or more, the effect corresponding thereto cannot be obtained.

Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples. In addition, this invention is not limited only to the following Examples.

"Production of resin (A)"
(Production Example 1)
[Preparation of first mixed solution]
As shown in Table 1, 23.9 parts by mass of acrylic acid, which is a carboxy group-containing ethylenically unsaturated monomer (a), and an ethylenically unsaturated monomer (d) copolymerizable with the above (a) With respect to a total of 100 parts by mass of a raw material monomer containing 71.8 parts by mass of n-butyl acrylate and 143.6 parts by mass of 2-ethylhexyl acrylate and a carboxy group-containing resin (b). Thus, a first mixed solution containing 0.1 parts by mass of 2,2'-azobisisobutyronitrile as a polymerization initiator was prepared.

[Preparation of second mixed solution]
As shown in Table 1, 5,9.8 parts by mass of 3,4-epoxycyclohexylmethyl methacrylate, which is an alicyclic epoxy group-containing ethylenically unsaturated compound (c), carboxy group-containing resin (b), and alicyclic epoxy With respect to a total of 100 parts by mass of the group-containing ethylenically unsaturated monomer (c), 0.6 parts by mass of tris (4-methylphenyl) phosphine (TPTP) as a catalyst and 100 parts of n-butyl acetate as a solvent A second mixed solution containing 0.0 parts by mass and 91.1 parts by mass of toluene was prepared.

(7) 175.6 parts by mass of n-butyl acetate as a solvent was charged into a four-necked flask equipped with a stirrer, a dropping funnel, a cooling tube and a nitrogen inlet tube, and the temperature was raised to 80 ° C. in a nitrogen gas atmosphere. Then, while maintaining the reaction temperature at 80 ° C. ± 2 ° C., the first mixed solution is uniformly dropped into the four-necked flask over 4 hours, and after completion of the dropping, at a temperature of 80 ° C. ± 2 ° C. for another 6 hours. The stirring was continued to polymerize the carboxy group-containing resin (b). Thereafter, the reaction system was charged with 0.15 g of 4-methoxyphenol as a polymerization inhibitor based on 100 parts by mass of the total of the carboxy group-containing resin (b) and the alicyclic epoxy group-containing ethylenically unsaturated monomer (c). Parts by weight were added.

The temperature of the reaction system to which 4-methoxyphenol was added was raised to 100 ° C., and the second mixed solution was added dropwise over 0.5 hour. Then, stirring was continued at a temperature of 100 ° C. for 8 hours to obtain resin (A-1). Was synthesized and cooled to room temperature (23 ° C.).
The resin (A-1) was identified by a nuclear magnetic resonance method (NMR method), and as a result, it was a compound represented by the general formula (2-1). In the compound represented by the general formula (2-1), the repeating unit k in the formula (1-1) is two kinds of repeating units (k-1, k-2) having different R ⁵ .

(In the formula (2-1), k-1 is 34, k-2 is 47, m is 1, and the sum of k-1, k-2, and m is 82. n is 18 Is.)

The resin (A-1) was examined for weight average molecular weight and glass transition temperature by the following method. The acid value of the resin (A-1) was measured according to JIS K0070. Table 3 shows the results.

<Weight average molecular weight (Mw)>
It was measured at room temperature under the following conditions using gel permeation chromatography (manufactured by Showa Denko KK, Showdex (registered trademark) GPC-101), and calculated in terms of polystyrene.
Column: Showdex (registered trademark) LF-804, manufactured by Showa Denko KK
Column temperature: 40 ° C
Sample: 0.2 mass% resin (A) tetrahydrofuran solution Flow rate: 1 ml / min Eluent: tetrahydrofuran Detector: RI detector

<Glass transition temperature (Tg)>
A 10 mg sample was collected from resin (A). Using a differential scanning calorimeter (DSC), the temperature of the sample was changed from −100 ° C. to 200 ° C. at a heating rate of 10 ° C./min, and the differential scanning calorimetry was performed. Was defined as Tg. In addition, when two Tg were observed, it was made into the simple average value of two Tg.

(Production Examples 2 to 8, 10 to 12)
Using the carboxy group-containing ethylenically unsaturated monomer (a), the ethylenically unsaturated monomer (d), and the polymerization initiator at the contents (parts by mass) shown in Tables 1 and 2. Except for the above, a first mixed solution was prepared in the same manner as in Production Example 1.
The alicyclic epoxy group-containing ethylenically unsaturated compound (c) (Glycidyl methacrylate (GMA) in Production Example 8) and the catalyst were used at the contents (parts by mass) shown in Tables 1 and 2. A second mixed solution was prepared in the same manner as in Production Example 1 except for the following.

Resins (A-2) to (A-8) (A-10) to (A-12) were obtained in the same manner as in Production Example 1 except that the first mixed solution and the second mixed solution were used. Was.
As a result of identifying the resins (A-2) to (A-8) (A-10) to (A-12) in the same manner as in Production Example 1, the resins represented by the general formulas (2-2) to (2-8) ( 2-10) to (2-12). In the compounds represented by the general formulas (2-2) to (2-8) and (2-10), the repeating unit k in the formula (1-1) is different from R ⁵ or 2 in which both R ¹ and R ⁵ are different. Kinds of repeating units (k-1, k-2).

The resin (A-2) is a compound represented by the following general formula (2-2).
The resin (A-3) is a compound represented by the following general formula (2-3).
The resin (A-4) is a compound represented by the following general formula (2-4).
The resin (A-5) is a compound represented by the general formula (2-5).
The resin (A-6) is a compound represented by the following general formula (2-6).
Resin (A-7) is a compound represented by the following general formula (2-7).
Resin (A-8) is a compound represented by the following general formula (2-8).
Resin (A-10) is a compound represented by the following general formula (2-10).
The resin (A-11) is a compound represented by the following general formula (2-11).
The resin (A-12) is a compound represented by the following general formula (2-12).

(In the formula (2-2), k-1 is 32, k-2 is 48, m is 1, and the sum of k-1, k-2, and m is 81. n is 19 Is.)
(In the formula (2-3), k-1 is 70, k-2 is 16, m is 1, and the sum of k-1, k-2, and m is 87. n is 13 Is.)

(In the formula (2-4), k-1 is 52, k-2 is 34, m is 3, and the sum of k-1, k-2, and m is 89. n is 11 Is.)
(In the formula (2-5), k-1 is 11, k-2 is 52, m is 4, the sum of k-1, k-2, and m is 67, and n is 33 Is.)

(In the formula (2-6), k-1 is 56, k-2 is 24, m is 0.2, and the sum of k-1, k-2, and m is 80.2. .N is 19.8.)
(In the formula (2-7), k-1 is 15, k-2 is 72, m is 1, and the sum of k-1, k-2, and m is 88. n is 12 Is.)

(In the formula (2-8), k-1 is 37, k-2 is 44, m is 2, and the sum of k-1, k-2, and m is 83. n 'is 17)
(In the formula (2-10), k-1 is 34, k-2 is 47, m is 4, and the sum of k-1, k-2, and m is 85. n is 15 Is.)

(In the formula (2-11), k is 66, 1 is 12, m is 2, and the sum of k, l, and m is 80. n is 20.)
(In the formula (2-12), k is 55, 1 is 23, m is 2, and the sum of k, l, and m is 80. n is 20.)

For the resins (A-2) to (A-8), (A-10) to (A-12), the weight average molecular weight, the glass transition temperature, and the acid value were determined in the same manner as the photosensitive resin (A-1). Examined. Table 3 shows the results.

(Production Example 9)
At the contents (parts by mass) shown in Table 2, except that the carboxy group-containing ethylenically unsaturated monomer (a), the ethylenically unsaturated monomer (d), and the polymerization initiator were used, A first mixed solution was prepared in the same manner as in Production Example 1.

(4) 261.7 parts by mass of ethyl acetate was charged as a solvent into a four-necked flask equipped with a stirrer, a dropping funnel, a cooling tube, and a nitrogen inlet tube, and heated under reflux. After heating under reflux, the first mixed solution shown in Table 2 was uniformly added dropwise over 4 hours. After the addition, stirring was continued under heating and refluxing for 6 hours. Thereafter, the reaction system was cooled to 60 ° C., and 286.4 parts by mass of ethyl acetate as a solvent and 100 parts by mass of a total of the carboxy group-containing resin (b) and the later-described 2-isocyanatoethyl methacrylate (MOI) were used. 0.15 parts by mass of 4-methoxyphenol as a polymerization inhibitor and 0 parts by weight of dioctyltin dilaurate as a catalyst are used for 100 parts by mass of the carboxy group-containing resin (b) and 2-isocyanatoethyl methacrylate (MOI) described later. 0.3 parts by mass.

After 4-methoxyphenol was dissolved, 47.8 parts by mass of 2-isocyanatoethyl methacrylate (MOI) was added to the reaction system, and stirring was continued at 60 ° C. for 8 hours to synthesize a resin (A-9). 23 ° C).
The resin (A-9) was identified in the same manner as in Production Example 1, and as a result, it was a compound represented by the general formula (2-9). In the compound represented by the general formula (2-9), the repeating unit k in the formula (1-1) is two kinds of repeating units (k-1, k-2) having different R ⁵ .

(In the formula (2-9), k-1 is 48, k-2 is 32, m is 1, and the sum of k-1, k-2, and m is 81. j is 2 And n ″ is 17.)

The resin (A-9) was examined for weight average molecular weight, glass transition temperature, and acid value in the same manner as for the resin (A-1). Table 3 shows the results.
For resins (A-1) to (A-12), k-1, k-2, and k (sum of k-1 and k-2) in chemical formulas (2-1) to (2-12) are respectively used. ), L, m, n, n ′, and n ″ are shown in Table 3.

Tables 1 and 2 show the carboxy group-containing ethylenically unsaturated monomer (a) used in the production of the resins (A-1) to (A-12), and the ethylene copolymerizable with the above (a). An unsaturated unsaturated monomer (d), a polymerization initiator, an alicyclic epoxy group-containing ethylenically unsaturated compound (c), a catalyst, a polymerization inhibitor and a type and amount of a solvent (parts by mass), The amounts (parts by mass) of glycidyl methacrylate (GMA) and 2-isocyanatoethyl methacrylate (MOI) are shown.

"Examples 1 to 12, Comparative Examples 1 and 2"
Ethyl acetate as a solvent was added to the reaction solution of the resins (A-1) to (A-12) synthesized in Production Examples 1 to 12, and the content of each of the resins (A-1) to (A-12) was reduced. It was adjusted to be 30% by mass. Using the resin (A-1) to (A-12) solution containing 30% by mass of the resin (A-1) to (A-12), a pressure-sensitive adhesive composition was obtained by the following method. .

In a plastic container in a room in which actinic radiation is blocked, the resin (A), the photopolymerization initiator (B), and the crosslinking agent (C) shown in Tables 4 to 6 are contained in the plastic containers shown in Tables 4 to 6, respectively. The resulting mixture was stirred in an amount (parts by mass) to obtain pressure-sensitive adhesive compositions of Examples 1 to 12 and Comparative Examples 1 and 2.
The numerical values of the resins (A-1) to (A-12) in Tables 4 to 6 indicate that the content of the resins (A-1) to (A-12) is 30% by mass. (A-12) The amount (parts by mass) of the solution used. The numerical value of the photopolymerization initiator (B) is the amount (parts by mass) of the photopolymerization initiator (B) used per 100 parts by mass of the resin (A). The numerical value of the crosslinking agent (C) is the amount (parts by mass) of the crosslinking agent (C) used per 100 parts by mass of the resin (A).

"TETRAD-C", "HX" and "TPO" in Tables 4 to 6 and "TETRAD-X" in Tables 4 and 5 are as follows.
"TETRAD-C" 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane (manufactured by Mitsubishi Gas Chemical Company, trade name: TETRAD-C)
"TETRAD-X" N, N '-[1,3-phenylenebis (methylene)] bis [bis (oxiran-2-ylmethyl) amine] (manufactured by Mitsubishi Gas Chemical Company, trade name: TETRAD-X)
"HX" isocyanurate of hexamethylene diisocyanate (trade name: Coronate (registered trademark) HX, manufactured by Tosoh Corporation)
“TPO” 2,4,6-trimethylbenzoyldiphenylphosphine oxide (BASF, trade name: L-TPO)

"Manufacture of adhesive sheets"
The pressure-sensitive adhesive compositions of Examples 1 to 12 and Comparative Examples 1 and 2 were applied as they were on a substrate so that the film thickness after drying became 20 μm, and dried by heating at 100 ° C. for 2 minutes. A layer was formed. Thereafter, a release sheet was laminated on the pressure-sensitive adhesive layer to obtain pressure-sensitive adhesive sheets of Examples 1 to 12 and Comparative Examples 1 and 2. A polyethylene terephthalate (PET) film having a thickness of 50 μm was used as the substrate and the release sheet.

粘着 With respect to the pressure-sensitive adhesive sheets of Examples 1 to 12 and Comparative Examples 1 and 2 thus obtained, the following items were evaluated by the following methods. The results are shown in Tables 4 to 6.

"Peel strength before UV irradiation"
The pressure-sensitive adhesive sheet was cut into a size of 25 mm in length and 100 mm in width, and the release sheet was peeled off to expose the pressure-sensitive adhesive layer. Next, the pressure-sensitive adhesive sheet was attached to the glass plate so that the exposed pressure-sensitive adhesive layer (measurement surface) was in contact with the glass plate, and a 2 kg rubber roller (width: about 50 mm) was moved back and forth once to obtain a peel strength before UV irradiation. Sample for measurement.
The obtained measurement sample was left for 24 hours in an environment at a temperature of 23 ° C. and a humidity of 50%. Thereafter, a 180 ° tensile test was performed at a peeling rate of 300 mm / min according to JIS Z0237 to measure the peeling strength (N / 25 mm) of the pressure-sensitive adhesive sheet to the glass plate.

"Peel strength after UV irradiation"
The same sample as the sample for measuring the peel strength before UV irradiation was prepared and irradiated with ultraviolet light (UV) from the surface on the side of the adhesive sheet under the condition of an irradiation amount of 500 mJ / cm ^{2 to} obtain a sample for measuring the peel strength after UV irradiation. . For UV irradiation, a conveyor-type ultraviolet irradiation device (2KW lamp, 80 W / cm, manufactured by Eye Graphics Co., Ltd.) was used.
About the obtained measurement sample, the peel strength (N / 25 mm) of the pressure-sensitive adhesive sheet to the glass plate was measured in the same manner as “peel strength before UV irradiation”.

"Release strength after heat resistant UV irradiation"
Prepare the same sample as the sample for measuring the peel strength before UV irradiation, perform heat treatment at 200 ° C. for 2 hours, cool to room temperature (23 ° C.), and apply UV under the same conditions as “peel strength after UV irradiation”. Irradiation was performed to obtain a sample for measurement of peel strength after heat-resistant UV irradiation.
About the obtained measurement sample, the peel strength (N / 25 mm) of the pressure-sensitive adhesive sheet to the glass plate was measured in the same manner as “peel strength after UV irradiation”.

"Glue residue"
The glass plate after the measurement of the peel strength after UV irradiation was visually observed and evaluated according to the following criteria. The results are shown in Tables 4 to 6.
(Evaluation criteria)
：: No adhesive remains on the glass plate.
Δ: Adhesive remained on part of the glass plate.
X: The adhesive remained on the entire surface of the glass plate.

As shown in Tables 4 and 5, the pressure-sensitive adhesive sheets of Examples 1 to 12 all had a "peel strength before UV irradiation" of 1.0 N / 25 mm or more, and a "peel strength after heat-resistant UV irradiation" of 2. It was less than 5 N / 25 mm, and the evaluation of adhesive residue was Δ or Δ.
In contrast, as shown in Table 6, the pressure-sensitive adhesive sheets of Comparative Examples 1 and 2 in which the resin (A) did not contain a structure derived from an alicyclic compound had sufficient “peel strength after UV irradiation”. Although it was low, the "peel strength after heat resistant UV irradiation" was high, and the evaluation of adhesive residue was x.

Claims (7)

1. An adhesive composition comprising a resin (A) represented by the following general formula (1-1) and a photopolymerization initiator (B).
   

   

   

   (In the formula (1-1), k, l, m, and n indicate a molar composition ratio when k + 1 + m + n = 100. K is more than 0 to 92 or less. L is 0 to 50. is greater than 0 to 90 or less is ^{.k, l, .R 1 ~ R} 4 the sum of m is 65 ~ 95 .n is 5-35 is -H or -CH ₃ .R ⁵ carbon R ⁶ is an alicyclic hydrocarbon group having 3 to 30 carbon atoms or an aromatic hydrocarbon group having 6 to 20 carbon atoms, and R ⁷ is —H or — (CH ₂ ) _J —COOH (where j is 1 or 2), and R ⁸ is the above general formula (1-2) or (1-3). In 3), p and q are any one selected from 0, 1, and 2. s is 0 when p is 0, and 1 when p is 1 or 2. .R ⁹ is -H or -CH _3.)
2. 粘着 The pressure-sensitive adhesive composition according to claim 1, wherein the resin (A) has a weight average molecular weight of 200,000 to 1,000,000.
3. 粘着 The pressure-sensitive adhesive composition according to claim 1, wherein n in the formula (1-1) is 10 to 33.
4. The method according to any one of claims 1 to 3, wherein k in the formula (1-1) is 45 to 90, l is 4 to 40, and m is 1 to 15. Pressure-sensitive adhesive composition.
5. The pressure-sensitive adhesive composition according to any one of claims 1 to 4, further comprising a crosslinking agent (C).
6. 粘着 The pressure-sensitive adhesive composition according to any one of claims 1 to 5, wherein the resin (A) has a glass transition temperature of -80 to 0 ° C.
7. It has a sheet-like substrate and an adhesive layer formed on the substrate, and the adhesive layer contains the adhesive composition according to any one of claims 1 to 6. An adhesive sheet characterized by the above-mentioned.