JPWO2020049829A1 - Adhesive composition and adhesive sheet - Google Patents

Abstract

A pressure-sensitive adhesive composition containing the resin represented by the formula (1-1) and a photopolymerization initiator is prepared. R1 to R4 are -H or -CH3. R5 is an alkyl group having 1 to 16 carbon atoms. R6 is an alicyclic hydrocarbon group or an aromatic hydrocarbon group. R7 is -H or-(CH2) j-COOH (j in the formula is 1 or 2). R8 is a specific group. [Chemical 1]

Description

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

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

In Patent Document 1, a (meth) acrylic polymer having two or more hydroxyl groups in a side chain and a compound having an isocyanato group are reacted in the presence of a first catalyst to have a urethane bond (meth) acrylic polymer. The step of forming the polymer and the reaction of the (meth) acrylic polymer having a urethane bond with a compound having two or more isocyanato groups in one molecule are allowed to react in the presence of a second catalyst to form a pressure-sensitive adhesive layer. A method for producing a pressure-sensitive adhesive sheet, which comprises a step of forming, 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 is disclosed.

Japanese Patent No. 5996985

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

The present invention has been made in view of the above circumstances, and by using it as a material for forming the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet, it has sufficient adhesive strength to the adherend and the pressure-sensitive adhesive sheet is attached. Provided is a pressure-sensitive adhesive composition capable of obtaining an adhesive sheet having excellent peelability and less adhesive residue even when the body is brought to a high temperature, returned to room temperature, UV-irradiated and then peeled off. Is the subject.
Another object of the present invention is to provide a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer containing the above-mentioned pressure-sensitive adhesive composition.

The present inventor has made extensive studies in order to solve the above problems. As a result, the carboxy group-containing resin (b) obtained by polymerizing the carboxy group-containing ethylenically unsaturated monomer (a) as an essential monomer component, and the alicyclic epoxy group-containing ethylenically unsaturated compound (c). It has been found that a pressure-sensitive adhesive composition containing the resin (A) obtained by the addition reaction with and the photopolymerization initiator (B) as essential components 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, when irradiated with ultraviolet rays (UV), unsaturated bonds in the resin (A) form a three-dimensional crosslinked structure and are cured, and the adhesive strength is changed. Specifically, sufficient adhesive strength to the adherend is obtained before the pressure-sensitive adhesive composition is irradiated with UV, and the adhesive strength is reduced after irradiation with UV to obtain excellent easy peeling property. At the same time, it is possible to sufficiently prevent adhesive residue on the adherend after peeling.
The present inventor came up with 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).

（式（１−１）において、ｋ、ｌ、ｍ、ｎは、ｋ＋ｌ＋ｍ＋ｎ＝１００としたときのモル組成比を示す。ｋは０超〜９２以下である。ｌは０〜５０である。ｍは０超〜９０以下である。ｋ、ｌ、ｍの合計は６５〜９５である。ｎは５〜３５である。Ｒ^１〜Ｒ^４は−Ｈまたは−ＣＨ_３である。Ｒ^５は炭素数１〜１６のアルキル基である。Ｒ^６は炭素数３〜３０の脂環式炭化水素基または炭素数６〜２０の芳香族炭化水素基である。Ｒ^７は−Ｈまたは−（ＣＨ_２）_ｊ−ＣＯＯＨ（式中のｊは１または２である。）である。Ｒ^８は上記一般式（１−２）または（１−３）である。式（１−２）および（１−３）において、ｐおよびｑは０、１、２から選ばれるいずれかである。ｓはｐが０のときは０であり、ｐが１または２のときは１である。Ｒ^９は−Ｈまたは−ＣＨ_３である。）

(In the formula (1-1), k, l, m, n indicate the molar composition ratio when k + l + m + n = 100. K is more than 0 to 92 or less. L is 0 to 50. M. Is more than 0 to 90 or less. The sum of k, l, and m is 65 to 95. N is 5 to 35. R ^{1 to} R ⁴ is -H or -CH _3. R ⁵ is carbon. It is an alkyl group having a ^{number of 1 to 16. R 6} is an alicyclic hydrocarbon group having 3 to 30 carbon atoms or an aromatic hydrocarbon group having 6 to 20 carbon atoms. R ⁷ is −H or − (CH _2). ) _{J-COOH (j in the} formula is 1 or 2). R ⁸ is the above general formula (1-2) or (1-3). Formulas (1-2) and (1- In 3), p and q are either 0, 1, or 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 above formula (1-1) is 45 to 90, l is 4 to 40, and m is 1 to 15. The pressure-sensitive adhesive composition according to the above.

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

[7] The pressure-sensitive adhesive composition according to any one of [1] to [6], which has a sheet-like base material and a pressure-sensitive adhesive layer formed on the base material. Adhesive sheet characterized by containing.

By using the pressure-sensitive adhesive composition of the present invention as a material for forming the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet, it has sufficient adhesive strength to the adherend, and the adherend to which the pressure-sensitive adhesive sheet is attached is brought into a high temperature state. Even if the material is returned to room temperature, UV-irradiated, and then peeled off, an excellent peelable property can be obtained, and an adhesive sheet in which adhesive residue is less likely to occur can be obtained.

Hereinafter, the pressure-sensitive adhesive composition and the pressure-sensitive adhesive sheet of the present invention will be described in detail. The present invention is not limited to the embodiments shown 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).

（式（１−１）において、ｋ、ｌ、ｍ、ｎは、ｋ＋ｌ＋ｍ＋ｎ＝１００としたときのモル組成比を示す。ｋは０超〜９２以下である。ｌは０〜５０である。ｍは０超〜９０以下である。ｋ、ｌ、ｍの合計は６５〜９５である。ｎは５〜３５である。Ｒ^１〜Ｒ^４は−Ｈまたは−ＣＨ_３である。Ｒ^５は炭素数１〜１６のアルキル基である。Ｒ^６は炭素数３〜３０の脂環式炭化水素基または炭素数６〜２０の芳香族炭化水素基である。Ｒ^７は−Ｈまたは−（ＣＨ_２）_ｊ−ＣＯＯＨ（式中のｊは１または２である。）である。Ｒ^８は上記一般式（１−２）または（１−３）である。式（１−２）および（１−３）において、ｐおよびｑは０、１、２から選ばれるいずれかである。ｓはｐが０のときは０であり、ｐが１または２のときは１である。Ｒ^９は−Ｈまたは−ＣＨ_３である。）

(In the formula (1-1), k, l, m, n indicate the molar composition ratio when k + l + m + n = 100. K is more than 0 to 92 or less. L is 0 to 50. M. Is more than 0 to 90 or less. The sum of k, l, and m is 65 to 95. N is 5 to 35. R ^{1 to} R ⁴ is -H or -CH _3. R ⁵ is carbon. It is an alkyl group having a ^{number of 1 to 16. R 6} is an alicyclic hydrocarbon group having 3 to 30 carbon atoms or an aromatic hydrocarbon group having 6 to 20 carbon atoms. R ⁷ is −H or − (CH _2). ) _{J-COOH (j in the} formula is 1 or 2). R ⁸ is the above general formula (1-2) or (1-3). Formulas (1-2) and (1- In 3), p and q are either 0, 1, or 2. s is 0 when p is 0 and 1 when p is 1 or 2. R ⁹ is −H. Or -CH _3. )

In formula (1-1), k, l, m, and n indicate the molar composition ratio when k + l + m + n = 100. k is more than 0 to 92 or less. l is 0 to 50. m is more than 0 to 90 or less. The total 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 has sufficient adhesiveness to the adherend before UV irradiation. The total of k, l, and m is preferably 70 to 94, more preferably 80 to 90.

In the formula (1-1), the repeating unit shown in () enclosed in k (hereinafter, referred to as “repeating unit k”) is an essential repeating unit. The repeating unit k contributes to the adhesive strength of the pressure-sensitive 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), the repeating unit shown in () enclosed in l (hereinafter, referred to as “repeating unit l”) may not be provided. In other words, the number of repetitions of the repeating unit l may be 0.
The repeating unit l contributes to the heat resistance of the pressure-sensitive adhesive composition. The number of repetitions l of the repeating unit l is 0 to 50, preferably 4 to 40, and more preferably 5 to 30.

In the formula (1-1), the repeating unit shown in () enclosed in 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 pressure-sensitive adhesive composition before UV irradiation. When the pressure-sensitive adhesive composition contains 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 force of the pressure-sensitive adhesive composition. The number of repetitions m of the repeating unit m is more than 0 to 90 or less, preferably 1 to 15, and more preferably 1 to 5.

In the formula (1-1), the repeating unit shown in () enclosed in n (hereinafter, referred to as “repeating unit 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, and more preferably 10 to 20. When the repeating unit n is 35 or less, the unsaturated bond in the resin (A) forms a three-dimensional crosslinked structure and is cured by UV irradiation, and the adhesive strength is reduced to an appropriate range. Become. Further, when n is 5 or more, the effect of improving heat resistance due to the structure derived from the alicyclic compound can be obtained.

Due to the synergistic effect of the functions contributed by each of these repeating units, the pressure-sensitive adhesive composition containing the resin (A) has a better balance between the adhesive strength before ultraviolet (UV) irradiation and the adhesive strength after UV irradiation. Become. As a result, a pressure-sensitive adhesive composition is obtained in which sufficient adhesive strength is obtained for the adherend before UV irradiation, and the adhesive strength is reduced after UV irradiation to obtain more excellent peelability. Moreover, this pressure-sensitive adhesive composition does not have an excessively high adhesive strength even when the temperature is raised to a high temperature before UV irradiation and then returned to room temperature, and excellent peelability after UV irradiation can be obtained, and the coating after peeling can be obtained. Adhesive residue on the body is unlikely to occur.

In the repeating unit k, R ¹ is −H or −CH ₃ and is 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.

Repeating units k may be a repeating unit of a plurality of types having different R ^1, 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 composition ratios of the plurality of types of repeating units. For example, when the repeating unit k ^{includes different repeating units A and B of R 1} and / or R ⁵ , the molar composition ratio of the repeating unit A is 2 mol%, and the molar composition ratio 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 l, R ² is −H or −CH ₃ and is 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 is an alicyclic hydrocarbon group having 6 to 20 carbon atoms or an aromatic hydrocarbon group having 6 to 10 carbon atoms. Group hydrocarbon groups are preferred.
Repeating units l may be a repeating unit of a plurality of types having different R ^2, R ^6. When the repeating unit l includes a plurality of types of repeating units, the molar composition ratio l of the repeating unit l indicates the total of the molar composition ratios of the plurality of types of repeating units.

In the repeating unit m, R ³ is −H or −CH ₃ and is preferably −H. R ⁷ is −H or − (CH ₂ ) _{j −COOH (j in the} formula is 1 or 2), preferably −H.
Repeating units m may be a repeating unit of a plurality of types having different R ^3, R ^7. In this case, the molar composition ratio m of the repeating unit m indicates the total of the molar composition ratios of the plurality of types of repeating units.

In the repeating unit n, ^{R 4} is -H or -CH _3, preferably a -H. R ⁸ is of formula (1-2) or (1-3). Each of the groups represented by the formula (1-2) or (1-3) contains a structure derived from an alicyclic compound and has a function of improving the heat resistance of the pressure-sensitive adhesive composition. In formula (1-2) or (1-3), p and q are either 0, 1, or 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 different types of repeating units of ^{R 4} and R ^8. In this case, the molar composition ratio n of the repeating unit n indicates the total of the molar composition ratios of the plurality of types of repeating units.

The resin (A) represented by the formula (1-1) is a random copolymer, a block copolymer, or an alternating copolymer composed of a repeating unit k, a repeating unit l, a repeating unit m, and a repeating unit n. It may be any of. The resin (A) represented by the formula (1-1) does not have to contain the repeating unit l, and is a random copolymer or block copolymer composed of the repeating unit k, the repeating unit m, and the repeating unit n. , Alternate copolymers may be used.

The weight average molecular weight of the resin (A) is preferably 200,000 to 1,000,000, more preferably 300,000 to 800,000. When the weight average molecular weight of the resin (A) is 200,000 or more, the pressure-sensitive adhesive layer is attached to the adherend when the pressure-sensitive adhesive sheet having the pressure-sensitive adhesive layer containing the pressure-sensitive adhesive composition is attached to the adherend and then peeled off. It becomes more difficult to remain. When the weight average molecular weight of the resin (A) is 1 million or less, the viscosity of the resin (A) does not become too high, and the effect of good workability 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 −80 to 0 ° C., more preferably −60 to −10 ° C., and even more preferably −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 pressure-sensitive 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, there is no adhesion contamination (glue residue) after heating, which is good. Further, when the pressure-sensitive adhesive composition contains a cross-linking agent, when the acid value of the resin (A) is within the above range, the resin (A) reacts with the cross-linking 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.

(Manufacturing 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 method shown below.
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 contain a monomer that forms the repeating unit k after polymerization, and may contain a monomer that forms the skeleton of the repeating unit l.
Next, the 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 in 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, and carboxypentyl (meth) acrylate.
Among these, as the carboxy group-containing ethylenically unsaturated monomer (a), it is preferable to use (meth) acrylic acid and / or β-carboxyethyl (meth) acrylate in terms of reactivity.

As used herein, the term (meth) acrylic means "acrylic" or "methacryl". The (meth) acrylate means "acrylate" or "methacrylate".

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

As the ethylenically unsaturated monomer (d), one or more kinds of monomers that form a skeleton of the repeating unit k by polymerization are used. As the ethylenically unsaturated monomer (d), one or more kinds of monomers that form a skeleton of a repeating unit k by polymerization and one or more monomers that form a skeleton of a repeating unit l by polymerization are used. May be good.

The ethylenically unsaturated monomer (d) that forms the 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 is preferable to contain an alkyl (meth) acrylate having 2 to 16 carbon atoms, and more preferably to contain 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. Examples thereof include (meth) acrylate, isodecyl (meth) acrylate, n-hexyl (meth) acrylate, isooctyl (meth) acrylate, and lauryl (meth) acrylate. Among these, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and isooctyl (meth) acrylate are preferable.

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

Examples of the cyclic alkyl group-containing (meth) acrylate having 3 to 30 carbon atoms used as the ethylenically unsaturated monomer (d) that forms the skeleton of the repeating unit l 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 Examples thereof include ethyl (meth) acrylate and tricyclodecanedimethylol di (meth) acrylate. 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 aromatic group-containing (meth) acrylate having 6 to 20 carbon atoms used as the ethylenically unsaturated monomer (d) that forms the skeleton of the repeating unit l by polymerization are benzyl (meth) acrylate and phenoxyethyl. Examples thereof include (meth) acrylate, phenoxypolyethylene glycol (meth) acrylate, phenoxypropyl (meth) acrylate, and phenoxypolyethylene glycol (meth) acrylate. Among these, it is particularly preferable to use benzyl (meth) acrylate. When the raw material monomer of the carboxy group-containing resin (b) contains an aromatic group-containing (meth) acrylate, the pressure-sensitive adhesive composition containing the resin (A) produced using the carboxy group-containing resin (b). The heat resistance of the object is improved.

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

Examples of the ethylenically unsaturated monomer copolymerizable with the carboxy group-containing ethylenically unsaturated monomer (a) other than the above ethylenically unsaturated monomer (d) include alkoxyalkyl (meth) acrylate. Examples thereof include alkoxy (poly) alkylene glycol (meth) acrylate, hydroxy group-containing (meth) acrylate, fluorinated alkyl (meth) acrylate, dialkylaminoalkyl (meth) acrylate, and (meth) acrylamide.

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

Examples of the alkoxy (poly) alkylene glycol (meth) acrylate include 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, and 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 and N, N-diethylaminoethyl (meth) acrylate.

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) acryloylmorpholin, diacetone acrylamide and the like.

Specific examples of the monomer copolymerizable with the carboxy group-containing ethylenically unsaturated monomer (a) other than the ethylenically unsaturated monomer (d) include acrylonitrile, methacrylonitrile, styrene, and the like. α-Methylstyrene, vinyl acetate, vinyl propionate, vinyl stearate, vinyl chloride, vinylidene chloride, alkyl vinyl ether, vinyl toluene, N-vinylpyridine, N-vinylpyrrolidone, itaconic acid dialkyl ester, fumaric acid dialkyl ester, allyl alcohol , Hydroxybutyl vinyl ether, hydroxyethyl vinyl ether, 4-hydroxymethylcyclohexylmethylvinyl ether, triethylene glycol monovinyl ether or diethylene glycol monovinyl ether, methylvinyl ketone, allyltrimethylammonium chloride, dimethylallylvinyl ketone and the like.

The method for producing the carboxy group-containing resin (b) is not particularly limited.
For example, a known polymerization of 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). It is obtained by copolymerizing by the method.
Specifically, as the polymerization method, a solution polymerization method, an emulsion polymerization method, a lump polymerization method, a suspension polymerization method, an alternating copolymerization method and 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), the solution is easy to react. It is preferable to use a polymerization method.

When the carboxy group-containing resin (b) is produced by the solution polymerization method, a radical polymerization initiator and / or a solvent is used, if necessary.
The radical polymerization initiator is not particularly limited, and can be appropriately selected and used 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) -Trimethylpentane), azo-based polymerization initiators such as dimethyl-2,2'-azobis (2-methylpropionate); benzoyl peroxide, t-butyl hydroperoxide, di-t-butyl peroxide, t- Peroxides such as butylperoxybenzoate, dicumyl peroxide, 1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane, 1,1-bis (t-butylperoxy) cyclododecane, etc. An oil-soluble polymerization initiator such as a system polymerization initiator is exemplified.

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

As the polymerization solvent used in 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 methylethylketone, methylisobutylketone, glycols such as ethylene glycol, propylene glycol, dipropylene glycol, methyl cellosolve, propylene glycol monomethyl ether, dipropylene glycol monomethyl Examples thereof include glycol ethers such as ethers, 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 components contained as necessary. 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 preferable. By setting the content of the carboxy group-containing ethylenically unsaturated monomer (a) in the raw material monomer within the above range, the carboxy group-containing resin (b) and the alicyclic epoxy group-containing ethylenically unsaturated compound ( The adhesive strength of the adhesive layer obtained from the adhesive composition containing the resin (A) produced by the addition reaction with c) before UV irradiation 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 is of the general formula (1-2) or the general formula (1-3). It is a compound that gives a structure. The alicyclic epoxy group in the present embodiment means 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 the following partial structural formula (1-2') or (1-2-') in the repeating unit n of the photosensitive resin (A) represented by the formula (1-1). It is used to add 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). ..

（式（１−２’）および（１−３’）において、ｑは０、１、２から選ばれるいずれかである。Ｒ^９は−Ｈまたは−ＣＨ_３である。）

(In equations (1-2') and (1-3'), q is either 0, 1, ^{or 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 formulas (1) or (2).

（式（１）において、Ｒ^９は−Ｈまたは−ＣＨ_３である。ｑは０、１、２から選ばれるいずれかである。）
（式（２）において、Ｒ^９は−Ｈまたは−ＣＨ_３である。ｑは０、１、２から選ばれるいずれかである。）

(In formula (1), R ⁹ is -H or -CH _3. q is either 0, 1, or 2.)
(In equation (2), R ⁹ is -H or -CH _3. q is either 0, 1, or 2.)

In 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 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), and 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 subjecting the carboxy group of the carboxy group-containing resin (b) to an addition reaction of the alicyclic epoxy group of the alicyclic epoxy group-containing ethylenically unsaturated monomer (c). Can be manufactured.
The resin (A) is preferably 0.2 to 0.99 mol, more preferably 0.3 to 0.95 mol, still more preferably 0.6 to 0, based on 1 mol of the carboxy group of the carboxy group-containing resin (b). It is preferably produced by an addition reaction of 95 mol of an alicyclic epoxy group-containing ethylenically unsaturated compound (c). 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) in the above ratios is prepared before UV irradiation. Sufficient adhesiveness to the adherend is obtained, and after UV irradiation, the adhesive strength is reduced and more excellent peelability can be obtained. Moreover, this pressure-sensitive adhesive composition does not easily increase its adhesive strength even when it is heated to a high temperature before UV irradiation and then returned to room temperature, and excellent peelability can be obtained after UV irradiation, and it can be applied to an adherend after peeling. It is possible to prevent the adhesive residue of the material more effectively.

The temperature of the addition reaction in producing the resin (A) is preferably 80 to 130 ° C, particularly preferably 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 the double bond portion from being crosslinked by radical polymerization by heat to form a gelled product.

A known catalyst can be used for the addition reaction in producing 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] nona-5-ene. , Tertiary amines such as 1,4-diazabicyclo [2,2,2] octane, quaternary ammonium salts such as tetramethylammonium chloride, tetramethylammonium bromide, tetrabutylammonium bromide, alkylurea such as tetramethylurea, tetra Alkylguanidines such as methylguanidine, triphenylphosphine, dimethylphenylphosphine, tricyclohexylphosphine, tributylphosphine, tris (4-methylphenyl) phosphine, tris (4-methoxyphenyl) phosphine, tris (2,6-dimethylphenyl) phosphine , Tris (2,6-dimethoxyphenyl) phosphine, tris (2,4,6-trimethylphenyl) phosphine, tris (2,4,6-trimethoxyphenyl) phosphine and other phosphine compounds.
Among the above, it is preferable to use a phosphine compound as a catalyst for the addition reaction in terms of reactivity.

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

Further, at the time of the addition reaction, a gas having a polymerization inhibitory effect may be introduced into the reaction system, or a polymerization inhibitor may be added. By introducing a gas having a polymerization inhibitory effect into the reaction system or adding a polymerization inhibitor, gelation during the addition reaction can be prevented.
Examples of the gas having a polymerization inhibitory effect include a gas containing oxygen that does not fall within the explosive range of the substance in the system, for example, air.

As the polymerization inhibitor, known ones can be used and are not particularly limited, but for example, 4-methoxyphenol, hydroquinone, methquinone, 2,6-di-t-butylphenol, 2,2'-methylenebis ( 4-Methyl-6-t-butylphenol), phenothiazine and the like. Only one kind of these polymerization inhibitors may be used, or two or more kinds thereof may be used in combination.

The amount of the polymerization inhibitor used is 0.005 to 5 parts by mass with respect to 100 parts by mass in total of the carboxy group-containing resin (b) and the alicyclic epoxy group-containing ethylenically unsaturated monomer (c). Is preferable, 0.03 to 3 parts by mass is more preferable, and 0.05 to 1.5 parts by mass is most preferable. If the amount of the polymerization inhibitor is too small, the polymerization inhibitor 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.
Further, it is more preferable to use a gas having a polymerization inhibitory effect in combination with a polymerization inhibitor because the amount of the polymerization inhibitor used can be reduced and the polymerization inhibitory effect can be enhanced.

(Photopolymerization Initiator (B))
Examples of the photopolymerization initiator (B) contained in the pressure-sensitive adhesive composition include benzophenone, benzyl, benzoin, ω-bromoacetophenone, chloroacetophenone, acetophenone, 2,2-diethoxyacetophenone, and 2,2-dimethoxy-2. -Phenylacetophenone, p-dimethylaminoacetophenone, p-dimethylaminopropiophenone, 2-chlorobenzophenone, 4,4'-dichlorobenzophenone, 4,4'-bisdiethylaminobenzophenone, Michler ketone, benzoin methyl ether, benzoin isobutyl ether, Benzoin-n-butyl ether, benzylmethylketal, 1-hydroxycyclohexylphenylketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1- (4-isopropylphenyl) -2-hydroxy-2- Methylpropane-1-one, methylbenzoylformate, 2,2-diethoxyacetophenone, 4-N, N'-dimethylacetophenone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane Examples thereof include a carbonyl-based photopolymerization initiator such as -1-one.

Examples of the photopolymerization initiator (B) include sulfide-based photopolymerization initiators such as diphenyl disulfide, dibenzyl disulfide, tetraethylthium disulfide, and tetramethylammonium monosulfide; 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,4. Acylphosphine oxides such as 6-trimethylbenzoylphenylethoxyphosphine oxide; quinone-based photopolymerization initiators such as benzoquinone and anthraquinone; sulfochloride-based photopolymerization initiators; thioxanthone 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-mentioned photopolymerization initiator (B) may be used alone or in combination of two or more.

The amount of the photopolymerization initiator (B) contained in the pressure-sensitive adhesive composition is preferably 0.1 to 5.0 parts by mass, and 0.5 to 2.0 parts by mass with respect to 100 parts by mass of the resin (A). It is more preferable that it is a part. When the content of the photopolymerization initiator (B) with respect to 100 parts by mass of the resin (A) is 0.1 parts by mass or more, the pressure-sensitive adhesive composition is cured at a sufficiently high curing rate by UV irradiation, and UV The adhesive strength of the pressure-sensitive adhesive composition after irradiation is sufficiently small, which is preferable. When the content of the photopolymerization initiator (B) is 5.0 parts by mass or less, the pressure-sensitive adhesive sheet having the pressure-sensitive adhesive layer containing the pressure-sensitive adhesive composition is adhered to the adherend and then peeled off. The agent layer is less likely to remain on the adherend. Further, even if the content of the photopolymerization initiator (B) exceeds 5.0 parts by mass, no effect commensurate with the content of the photopolymerization initiator (B) is observed.

(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 the cross-linking agent (C). By containing the cross-linking agent (C), the pressure-sensitive adhesive composition has a better balance between the adhesive strength before UV irradiation and the adhesive strength after UV irradiation.
The cross-linking agent (C) is not particularly limited, but 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 is preferable.

Examples of the cross-linking agent (C) include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, hydrogenated tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, and diphenylmethane-. 4,4-Diisocyanate, isophorone diisocyanate, 1,3-bis (N, N'-diglycidylaminomethyl) cyclohexane, 1,3-bis (isocyanatomethyl) cyclohexane, isocyanurate of hexamethylene diisocyanate, tetramethylxyli Isocyanate compounds such as range isocyanate, 1,5-naphthalenediocyanate, tolylene diisocyanate adduct of trimethylol propane, xylylene diisocyanate adduct of trimethylol propane, triphenylmethane triisocyanate, methylenebis (4-phenylmethane) triisocyanate. ,
Bisphenol A / epichlorohydrin type epoxy resin, N, N'-[1,3-phenylene bis (methylene)] bis [bis (oxylan-2-ylmethyl) amine], ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, Glycerin diglycidyl ether, glycerin triglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylpropan triglycidyl ether, sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl erythritol, diglycerol polyglycidyl ether, etc. Epoxy compounds,
Tetramethylolmethane-tri-β-aziridinyl propionate, trimethylolpropane-tri-β-aziridinyl propionate, N, N'-diphenylmethane-4,4'-bis (1-aziridinecarboxamide) , N, N'-Hexamethylene-1,6-bis (1-aziridinecarboxamide) and other aziridine compounds,
Examples thereof include melamine-based compounds such as hexamethoxymethylmelamine, hexaethoxymethylmelamine, hexapropoxymethylmelamine, hexaptoxymethylmelamine, hexapentyloxymethylmelamine, and hexahexyloxymethylmelamine.

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

The cross-linking 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). It is preferably 0.1 to 1.0 parts by mass, and more preferably 0.1 to 1.0 parts by mass. When the content of the cross-linking agent (C) with respect to 100 parts by mass of the resin (A) is 0.05 parts by mass or more, a three-dimensional cross-linked structure is sufficiently formed in the pressure-sensitive adhesive composition. As a result, the adhesive strength of the pressure-sensitive adhesive composition after UV irradiation becomes sufficiently small, which is preferable. When the content of the cross-linking agent (C) with respect to 100 parts by mass of the resin (A) is 10 parts by mass or less, the adhesive strength 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 cross-linking agent (C), if necessary.
Examples of other components include tackifiers, solvents, various additives and the like.

(Adhesive imparting agent)
As the tackifier, conventionally known ones can be used without particular limitation. Examples of the pressure-sensitive adhesive include terpen-based pressure-sensitive adhesive resins, phenol-based pressure-sensitive adhesive resins, rosin-based pressure-sensitive adhesive resins, aliphatic petroleum resins, aromatic petroleum resins, copolymerized petroleum resins, and alicyclic petroleum resins. , Xylene resin, epoxy-based pressure-sensitive adhesive resin, polyamide-based pressure-sensitive adhesive resin, ketone-based pressure-sensitive adhesive resin, elastomer-based pressure-sensitive adhesive 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 thereof is preferably 30 parts by mass or less, preferably 5 to 20 parts by mass, based on 100 parts by mass of the resin (A). More preferred.

(solvent)
The solvent can be used to dilute the pressure-sensitive adhesive composition for the purpose of adjusting the viscosity of the pressure-sensitive adhesive composition when the pressure-sensitive adhesive composition is applied.
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. 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, UV absorbers, polymerization inhibitors, light stabilizers such as benzotriazoles, and phosphate esters. Systems and other flame retardants, antistatic agents such as surfactants and the like.

[Manufacturing method of adhesive composition]
The pressure-sensitive adhesive composition of the present embodiment can be produced by a conventionally known method.
For example, the above-mentioned resin (A) and photopolymerization initiator (B) are mixed with a cross-linking agent (C), a tackifier, a solvent, and various additives contained as necessary by a conventionally known method. It can be produced by stirring.

The pressure-sensitive adhesive composition of the present embodiment is suitable as a material for forming the pressure-sensitive adhesive layer of the 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 the present embodiment contains the resin (A) represented by the formula (1-1) and the photopolymerization initiator (B), it is used as a material for forming the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet. Therefore, an adhesive sheet having sufficient adhesive strength to the adherend can be obtained. Moreover, even if the adherend to which the adhesive sheet is attached is heated to a high temperature and then returned to room temperature to be peeled off, excellent peelability can be obtained after UV irradiation, and adhesive residue is unlikely to occur.

"Adhesive sheet"
The pressure-sensitive adhesive sheet of the present invention has a sheet-like base material and a pressure-sensitive adhesive layer formed on the base material.
It is preferable that a release sheet (separator) is provided on the surface of the pressure-sensitive adhesive layer opposite to the base material. If a release sheet is provided on the pressure-sensitive adhesive layer, the release sheet can protect the pressure-sensitive adhesive layer until use. Further, when the release sheet is provided on the pressure-sensitive adhesive layer, the work of peeling off the release sheet to expose the pressure-sensitive adhesive layer and crimping the pressure-sensitive adhesive layer (sticking surface) to the adherend can be efficiently performed. ..
The adhesive sheet of the present embodiment may be used as an adhesive tape having a shape corresponding to the shape of the adherend by a punching method or the like. Further, the adhesive sheet of the present embodiment may be used as an adhesive tape by winding and cutting.

As the base material, a known sheet-like material can be appropriately selected and used. As the base material, it is preferable to use a resin sheet made of a transparent resin 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, PE, PP, and PET are preferably used 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 mixed and used.

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

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

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

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

The pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet of the present embodiment contains the above-mentioned pressure-sensitive adhesive composition.
The thickness of the pressure-sensitive adhesive layer is preferably 1 to 100 μm, more preferably 2 to 80 μm, and even more preferably 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 becomes good. On the other hand, when the thickness of the pressure-sensitive adhesive layer is 100 μm or less, the solvent can be easily removed even when the pressure-sensitive adhesive layer is formed by using a solvent, which is preferable.

When the 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 one as the above-mentioned resin sheet used as the base material can be used.
The thickness of the release sheet can be appropriately selected depending on the use of the 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 peeling surface (the surface arranged in contact with the pressure-sensitive adhesive layer) of the release sheet is peeled with a conventionally known release agent such as silicone-based, long-chain alkyl-based, or fluorine-based, if necessary. You may.

[Manufacturing method of adhesive sheet]
The pressure-sensitive adhesive sheet of the present embodiment can be manufactured, for example, by the method shown below.
First, a pressure-sensitive adhesive solution is prepared by dissolving or dispersing the above-mentioned pressure-sensitive adhesive composition in a solvent. The above-mentioned pressure-sensitive adhesive composition may be used as it is as a pressure-sensitive adhesive solution.
Next, the pressure-sensitive adhesive solution is applied onto the substrate and dried by heating to form a pressure-sensitive adhesive layer. After that, it is obtained by laminating a release sheet on the pressure-sensitive adhesive layer, if 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 the release sheet and dried by heating to form a pressure-sensitive adhesive layer. After that, a method of installing a release sheet having an adhesive layer on the base material and placing the surface on the pressure-sensitive adhesive layer side toward the base material and transferring (transferring) the pressure-sensitive adhesive layer onto the base material can be mentioned.

As a method of applying the above-mentioned pressure-sensitive adhesive solution on a substrate (or on a release sheet), a known method can be used. Specifically, there is a method of applying using a conventional coater, for example, 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 direct coater, or the like. Be done.

[Use 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. Specifically, the adhesive sheet of the present embodiment is adhered by irradiating ultraviolet rays (UV) after fixing the adherend and subjecting it to various processing steps in each step of manufacturing an electronic component. It is used for peeling and collecting the body. Therefore, the pressure-sensitive adhesive sheet of the present embodiment can be used as a back grind tape, a dicing tape, or the like when processing a semiconductor wafer. Further, the 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, a flexible printed circuit board (FPC substrate) or the like for a easily warped member. In particular, the pressure-sensitive adhesive sheet of the present embodiment is suitable as a dicing tape that protects the wafer when performing the dicing step of the wafer.

When the adhesive sheet of the present embodiment is used as a dicing tape for a wafer, the adhesive sheet is attached to a wafer on which a plurality of parts are formed before performing the dicing step. Next, the wafer is cut and cut (diced) into individual parts to obtain element small pieces (chips). After that, the adhesive sheet attached on each element small piece is irradiated with UV. As a result, the pressure-sensitive adhesive layer is irradiated with UV 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 pressure-sensitive adhesive layer is reduced. After that, the adhesive sheet is peeled off from the top of each element small piece.

Light sources used for UV irradiation on the adhesive sheet before peeling attached to the adherend include, for example, high-pressure mercury lamp, ultra-high pressure mercury lamp carbon arc lamp, xenon lamp, metal halide lamp, chemical lamp, and black. Lights and the like.
UV dose to be irradiated to the adhesive sheet is preferably 50 to 3000 mJ / 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 rate by UV irradiation, and the adhesive strength of the pressure-sensitive adhesive layer after UV irradiation is sufficient. Smaller and preferable. Even if the UV irradiation amount to irradiate the adhesive sheet is 3000 mJ / cm ² or more, the effect corresponding to it cannot be obtained.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. The present invention is not limited to the following examples.

"Manufacturing of resin (A)"
(Manufacturing 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 the raw material monomer containing 71.8 parts by mass of n-butyl acrylate and 143.6 parts by mass of 2-ethylhexyl acrylate and the raw material monomer of the carboxy group-containing resin (b). 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, 59.8 parts by mass of 3,4-epoxycyclohexylmethylmethacrylate, which is an alicyclic epoxy group-containing ethylenically unsaturated compound (c), a carboxy group-containing resin (b), and an alicyclic epoxy. 0.6 parts by mass of tris (4-methylphenyl) phosphine (TPTP) as a catalyst and n-butyl acetate 100 as a solvent with respect to a total of 100 parts by mass of the group-containing ethylenically unsaturated monomer (c). A second mixed solution containing 0.0 parts by mass and 91.1 parts by mass of toluene was prepared.

175.6 parts by mass of n-butyl acetate was charged as a solvent into a four-necked flask equipped with a stirrer, a dropping funnel, a cooling tube and a nitrogen introduction 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 was uniformly added dropwise to the four-necked flask over 4 hours, and after the addition was completed, the temperature was 80 ° C. ± 2 ° C. for another 6 hours. Stirring was continued to polymerize the carboxy group-containing resin (b). Then, in the reaction system, 4-methoxyphenol 0.15 as a polymerization inhibitor with respect to a total of 100 parts by mass of the carboxy group-containing resin (b) and the alicyclic epoxy group-containing ethylenically unsaturated monomer (c). Mass parts were added.

The reaction system to which 4-methoxyphenol was added was heated to 100 ° C., the second mixed solution was added dropwise over 0.5 hours, and then stirring was continued at a temperature of 100 ° C. for 8 hours to obtain the resin (A-1). Was synthesized and cooled to room temperature (23 ° C.).
As a result of identifying the resin (A-1) by the nuclear magnetic resonance method (NMR method), it was a compound represented by the general formula (2-1). Repeating units k in Equation (1-1) in the compound represented by general formula (2-1) are the two repeating units different ^{R 5 (k-1, k} -2).

（式（２−１）において、ｋ−１は３４であり、ｋ−２は４７であり、ｍは１であり、ｋ−１、ｋ−２、ｍの合計は８２である。ｎは１８である。）

(In equation (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.)

For the resin (A-1), the weight average molecular weight and the glass transition temperature were examined by the methods shown below. Moreover, the acid value of the resin (A-1) was measured according to JIS K0070. The results are shown in Table 3.

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

<Glass transition temperature (Tg)>
A 10 mg sample was taken from the resin (A). Using a differential scanning calorimeter (DSC), differential scanning calorimetry was performed by changing the temperature of the sample from -100 ° C to 200 ° C at a heating rate of 10 ° C / min, and the endothermic start temperature due to the observed glass transition. Was Tg. When two Tg were observed, the simple average value of the two Tg was used.

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

Resins (A-2) to (A-8) (A-10) to (A-12) are obtained in the same manner as in Production Example 1 except that the first mixed solution and the second mixed solution are used. rice field.
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 general formulas (2-2) to (2-8) ( It was a compound represented by 2-10) to (2-12). The repeating unit k in the formula (1-1) in the compounds represented by the general formulas (2-2) to (2-8) and (2-10) is R ⁵ or ^{both R 1} and R ⁵ are different 2 It is a repeating unit of the species (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 above general formula (2-5).
The resin (A-6) is a compound represented by the following general formula (2-6).
The resin (A-7) is a compound represented by the following general formula (2-7).
The resin (A-8) is a compound represented by the following general formula (2-8).
The 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).

（式（２−２）において、ｋ−１は３２であり、ｋ−２は４８であり、ｍは１であり、ｋ−１、ｋ−２、ｍの合計は８１である。ｎは１９である。）
（式（２−３）において、ｋ−１は７０であり、ｋ−２は１６であり、ｍは１であり、ｋ−１、ｋ−２、ｍの合計は８７である。ｎは１３である。）

(In equation (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 equation (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.)

（式（２−４）において、ｋ−１は５２であり、ｋ−２は３４であり、ｍは３であり、ｋ−１、ｋ−２、ｍの合計は８９である。ｎは１１である。）
（式（２−５）において、ｋ−１は１１であり、ｋ−２は５２であり、ｍは４であり、ｋ−１、ｋ−２、ｍの合計は６７であり、ｎは３３である。）

(In equation (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 equation (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.)

（式（２−６）において、ｋ−１は５６であり、ｋ−２は２４であり、ｍは０．２であり、ｋ−１、ｋ−２、ｍの合計は８０．２である。ｎは１９．８である。）
（式（２−７）において、ｋ−１は１５であり、ｋ−２は７２であり、ｍは１であり、ｋ−１、ｋ−２、ｍの合計は８８である。ｎは１２である。）

(In equation (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 equation (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.)

（式（２−８）において、ｋ−１は３７であり、ｋ−２は４４であり、ｍは２であり、ｋ−１、ｋ−２、ｍの合計は８３である。ｎ′は１７である。）
（式（２−１０）において、ｋ−１は３４であり、ｋ−２は４７であり、ｍは４であり、ｋ−１、ｋ−２、ｍの合計は８５である。ｎは１５である。）

(In equation (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 equation (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.)

（式（２−１１）において、ｋは６６であり、ｌは１２であり、ｍは２であり、ｋ、ｌ、ｍの合計は８０である。ｎは２０である。）
（式（２−１２）において、ｋは５５であり、ｌは２３であり、ｍは２であり、ｋ、ｌ、ｍの合計は８０である。ｎは２０である。）

(In equation (2-11), k is 66, l is 12, m is 2, and the sum of k, l, and m is 80. n is 20.)
(In equation (2-12), k is 55, l 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 set in the same manner as for the photosensitive resin (A-1). Examined. The results are shown in Table 3.

(Manufacturing Example 9)
Except for the use of the carboxy group-containing ethylenically unsaturated monomer (a), the ethylenically unsaturated monomer (d), and the polymerization initiator in the content (parts by mass) shown in Table 2. A first mixed solution was prepared in the same manner as in Production Example 1.

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 introduction tube, and reflux was carried out by heating. After heating and refluxing, the first mixed solution shown in Table 2 was uniformly added dropwise over 4 hours, and after the addition, stirring was continued for 6 hours by heating and refluxing. Then, the reaction system was cooled to 60 ° C., based on 286.4 parts by mass of ethyl acetate as a solvent, and a total of 100 parts by mass of the carboxy group-containing resin (b) and 2-isocyanatoethyl methacrylate (MOI) described later. 0.15 parts by mass of 4-methoxyphenol as a polymerization inhibitor, and 0 dioctyltin dilaurate as a catalyst for a total of 100 parts by mass of the carboxy group-containing resin (b) and 2-isocyanatoethyl methacrylate (MOI) described later. .3 parts by mass was added.

After the 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 the resin (A-9) at room temperature (A-9). It was cooled to 23 ° C.).
As a result of identifying the resin (A-9) in the same manner as in Production Example 1, it was a compound represented by the general formula (2-9). Repeating units k in Equation (1-1) in the compound represented by general formula (2-9) are the two repeating units different ^{R 5 (k-1, k} -2).

（式（２−９）において、ｋ−１は４８であり、ｋ−２は３２であり、ｍは１であり、ｋ−１、ｋ−２、ｍの合計は８１である。ｊは２であり、ｎ′′は１７である。）

(In equation (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 weight average molecular weight, the glass transition temperature, and the acid value of the resin (A-9) were examined in the same manner as the resin (A-1). The results are shown in Table 3.
Further, for the resins (A-1) to (A-12), the sum of k-1, k-2, and k (k-1 and k-2) in the chemical formulas (2-1) to (2-12), respectively. ), L, m, n, n ′, 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 ethylene copolymerizable with the above (a). Sexual unsaturated monomer (d), polymerization initiator, alicyclic epoxy group-containing ethylenically unsaturated compound (c), catalyst, polymerization inhibitor, type and amount of solvent (parts by mass), The amounts (parts by mass) of glycidyl methacrylate (GMA) and 2-isocyanatoethyl methacrylate (MOI) used are shown.

"Examples 1 to 12, Comparative Examples 1 to 2"
Ethyl acetate as a solvent was added to the reaction solutions of the resins (A-1) to (A-12) synthesized in Production Examples 1 to 12, and the contents of the resins (A-1) to (A-12) were increased, respectively. It was adjusted to be 30% by mass. A pressure-sensitive adhesive composition was obtained by the method shown below using a solution of resins (A-1) to (A-12) having a content of resins (A-1) to (A-12) of 30% by mass. ..

The resin (A), the photopolymerization initiator (B), and the cross-linking agent (C) shown in Tables 4 to 6 are contained in a plastic container in a room where the active rays are blocked, respectively, as shown in Tables 4 to 6, respectively. The pressure-sensitive adhesive compositions of Examples 1 to 12 and Comparative Examples 1 and 2 were obtained by adding in an amount (part by mass) and stirring.
The numerical values of the resins (A-1) to (A-12) in Tables 4 to 6 are the resins (A-1) in which the content of the resins (A-1) to (A-12) is 30% by mass. ~ (A-12) Amount of solution used (parts by mass). The numerical value of the photopolymerization initiator (B) is the amount (parts by mass) of the photopolymerization initiator (B) used with respect to 100 parts by mass of the resin (A). The numerical value of the cross-linking agent (C) is the amount (parts by mass) of the cross-linking agent (C) used with respect to 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 shown below, respectively.
"TETRAD-C" 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane (manufactured by Mitsubishi Gas Chemical Company, Inc., trade name: TETRAD-C)
"TETRAD-X" N, N'-[1,3-phenylene bis (methylene)] bis [bis (oxylan-2-ylmethyl) amine] (manufactured by Mitsubishi Gas Chemical Company, Inc., trade name: TETRAD-X)
"HX" hexamethylene diisocyanate isocyanurate (manufactured by Tosoh Corporation, trade name: Coronate (registered trademark) HX)
"TPO" 2,4,6-trimethylbenzoyldiphenylphosphine oxide (manufactured by BASF, trade name: L-TPO)

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

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

"Peeling strength before UV irradiation"
The 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 adhesive layer. Next, an adhesive sheet is attached to the glass plate so that the exposed adhesive layer (measurement surface) is in contact with the glass plate, and a 2 kg rubber roller (width: about 50 mm) is reciprocated once to achieve peel strength before UV irradiation. Was used as a measurement sample.
The obtained measurement sample was left to stand for 24 hours in an environment of a temperature of 23 ° C. and a humidity of 50%. Then, according to JIS Z0237, a tensile test was performed in the 180 ° direction at a peeling speed of 300 mm / min, and the peeling strength (N / 25 mm) of the pressure-sensitive adhesive sheet with respect to the glass plate was measured.

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

"Peeling strength after heat-resistant UV irradiation"
Prepare the same sample as the sample for measuring the peel strength before UV irradiation, heat-treat it at 200 ° C for 2 hours, cool it to room temperature (23 ° C), and UV under the same conditions as "peeling strength after UV irradiation". After irradiation, it was used as a sample for measuring the peel strength after heat-resistant UV irradiation.
For the obtained measurement sample, the peel strength (N / 25 mm) of the adhesive sheet with respect to the glass plate was measured in the same manner as in the “peeling strength after UV irradiation”.

"Remaining glue"
The glass plate after measuring 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 a part of the glass plate.
X: Adhesive remained on the entire surface of the glass plate.

As shown in Tables 4 and 5, the adhesive sheets of Examples 1 to 12 have a "peeling strength before UV irradiation" of 1.0 N / 25 mm or more and a "peeling strength after heat-resistant UV irradiation" of 2. It was less than 5N / 25mm, and the evaluation of the adhesive residue was 〇 or Δ.
On the other hand, as shown in Table 6, the pressure-sensitive adhesive sheets of Comparative Example 1 and Comparative Example 2 in which the resin (A) does not contain a structure derived from an alicyclic compound have sufficient "peeling strength after UV irradiation". Although it was low, the "peeling strength after heat-resistant UV irradiation" was high, and the evaluation of the adhesive residue was x.

Claims (7)

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, n indicate the molar composition ratio when k + l + m + n = 100. K is more than 0 to 92 or less. L is 0 to 50. M. Is more than 0 to 90 or less. The sum of k, l, and m is 65 to 95. N is 5 to 35. R ^{1 to} R ⁴ is -H or -CH _3. R ⁵ is carbon. It is an alkyl group having a ^{number of 1 to 16. R 6} is an alicyclic hydrocarbon group having 3 to 30 carbon atoms or an aromatic hydrocarbon group having 6 to 20 carbon atoms. R ⁷ is −H or − (CH _2). ) _{J-COOH (j in the} formula is 1 or 2). R ⁸ is the above general formula (1-2) or (1-3). Formulas (1-2) and (1- In 3), p and q are either 0, 1, or 2. s is 0 when p is 0 and 1 when p is 1 or 2. R ⁹ is −H. Or -CH _3. ) 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. The pressure-sensitive adhesive composition according to claim 1 or 2, wherein n in the formula (1-1) is 10 to 33. The invention 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. Adhesive composition. The pressure-sensitive adhesive composition according to any one of claims 1 to 4, further comprising a cross-linking agent (C). The pressure-sensitive adhesive composition according to any one of claims 1 to 5, wherein the glass transition temperature of the resin (A) is −80 to 0 ° C. It has a sheet-like base material and a pressure-sensitive adhesive layer formed on the base material, and the pressure-sensitive adhesive layer contains the pressure-sensitive adhesive composition according to any one of claims 1 to 6. Adhesive sheet characterized by that.