JP2022104402A - Adhesive composition, adhesive sheet, and optical member - Google Patents

Abstract

To provide an adhesive composition capable of forming an adhesive layer which hardly deforms even when cutting accompanied by high temperature is performed and which hardly causes unevenness of adhesive force due to partial thickness variation, and to provide an adhesive sheet and an optical member.SOLUTION: There are provided an adhesive composition and applications thereof. The adhesive composition contains: a (meth)acrylic copolymer containing a constituent unit (A) derived from a monomer having a crosslinkable functional group and a constituent unit (B) derived from an alkyl (meth)acrylate monomer, the content of the constituent unit (A) being 0.01-5 mass% based on all the constituent units; a polyrotaxane in which a cyclic molecule has a side chain containing two or more carbon atoms and the terminal of the side chain is a hydroxyl group; a crosslinking agent; and a silane coupling agent. The content of the polyrotaxane is 20-50 pts.mass based on 100 pts.mass of the (meth)acrylic copolymer, and the content of the crosslinking agent is 5-50 pts.mass based on 100 pts.mass of the (meth)acrylic copolymer.SELECTED DRAWING: None

Description

The present disclosure relates to pressure-sensitive adhesive compositions, pressure-sensitive adhesive sheets, and optical members.

With the diversification of the usage environment of the pressure-sensitive adhesive sheet, there is a demand for a pressure-sensitive adhesive capable of forming a pressure-sensitive adhesive layer having excellent durability, assuming use in various environments.
For example, Patent Document 1 describes an optical pressure-sensitive adhesive containing 100 parts by weight of an acrylic polymer and 5 parts by weight to 50 parts by weight of an isocyanate-based curing agent as a pressure-sensitive adhesive capable of forming a pressure-sensitive adhesive layer having excellent high-temperature durability. The agent is disclosed. According to Patent Document 1, it is possible to improve high temperature durability by increasing the cohesive force of the pressure-sensitive adhesive layer by using an isocyanate-based curing agent in a specific ratio or more with respect to the acrylic polymer.

By the way, in recent years, polyrotaxane has been attracting attention as a raw material for functional materials. Polyrotaxane is a compound consisting of a cyclic molecule, a linear molecule that penetrates the opening of the cyclic molecule in a skewered manner, and a blocking group that blocks both ends of the linear molecule, and is on the linear molecule. Has the effect that the cyclic molecule freely slides (so-called slide effect). Various reports have been made on functional materials using polyrotaxane as a raw material.
For example, Patent Document 2 is for a soft material containing a polyrotaxane having at least one cyclic molecule having two or more radically polymerizable groups and a radically polymerizable monomer which is a monofunctional (meth) acrylic acid ester. The composition is disclosed.
Further, Patent Document 3 discloses a pressure-sensitive adhesive containing an active energy ray-curable component and a polyrotaxane having an active energy ray-polymerizable group.

Japanese Unexamined Patent Publication No. 2011-37927 Japanese Patent No. 6258228 JP-A-2015-155530

In the process of processing the base material with the pressure-sensitive adhesive layer, cutting using a polishing machine may be performed. In cutting using a polishing machine, heat is easily generated by polishing, so that the adhesive layer may be deformed. Therefore, the pressure-sensitive adhesive layer is required to have a property of being hard to be deformed even when it is cut at a high temperature.

By the way, in recent years, devices having various shapes have been on the market, and in particular, devices having an uneven edge portion have attracted attention. When the adhesive sheet is attached to an adherend having an uneven edge portion, unlike the conventional case where the adhesive sheet is attached to an adherend having a flat shape as a whole, the adhesive layer always repels the base material. Stress is applied. Further, the adhesive layer tends to be thin in the uneven edge portion in the process, and the thickness of the adhesive layer varies around the edge portion, and the adhesive force tends to be uneven. In general, a portion where the thickness of the pressure-sensitive adhesive layer is thin tends to have a lower adhesive strength than a portion where the pressure-sensitive adhesive layer is thick, so that the portion is easily peeled off. Therefore, the pressure-sensitive adhesive layer is required to have a property that unevenness in the pressure-sensitive adhesive force due to a partial variation in thickness is unlikely to occur.

The present inventors have conducted diligent research to realize the formation of an adhesive layer that is not easily deformed even when cut with high temperature and is less likely to cause unevenness in adhesive force due to partial thickness variation. We have found that it is effective to use a specific polyrotaxane as a raw material for the pressure-sensitive adhesive.

The problem to be solved by one embodiment of the present disclosure is to form a pressure-sensitive adhesive layer that is not easily deformed even when cut with high temperature and is unlikely to cause unevenness in adhesive strength due to partial thickness variation. The purpose is to provide a pressure-sensitive adhesive composition that can be used.
The problem to be solved by the other embodiments of the present disclosure is to provide a pressure-sensitive adhesive layer that is not easily deformed even when cut with high temperature and is unlikely to cause unevenness in adhesive strength due to partial thickness variation. The purpose is to provide an adhesive sheet to be provided.
Further, the problem to be solved by the other embodiments of the present disclosure is that the pressure-sensitive adhesive is less likely to be deformed even when cut with high temperature, and the adhesive strength is less likely to be uneven due to partial thickness variation. It is an object of the present invention to provide an optical member provided with a layer.

Specific means for solving the problem include the following aspects.
<1> The above-mentioned structural unit (A) includes a structural unit (A) derived from a monomer having a crosslinkable functional group and a structural unit (B) derived from a (meth) acrylic acid alkyl ester monomer. A (meth) acrylic copolymer having a content of 0.01% by mass or more and 5% by mass or less with respect to all the constituent units.
Polyrotaxane in which the cyclic molecule has a side chain containing two or more carbon atoms and the end of the side chain is a hydroxyl group,
With a cross-linking agent,
Silane coupling agent and
Including
The content of the polyrotaxane is 20 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the (meth) acrylic copolymer.
A pressure-sensitive adhesive composition in which the content of the cross-linking agent is 5 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the (meth) acrylic copolymer.
<2> The pressure-sensitive adhesive composition according to <1>, wherein the glass transition temperature of the (meth) acrylic copolymer is less than 0 ° C.
<3> A pressure-sensitive adhesive sheet comprising the pressure-sensitive adhesive layer formed by the pressure-sensitive adhesive composition according to <1> or <2>.
<4> An optical member including a pressure-sensitive adhesive layer formed by the pressure-sensitive adhesive composition according to <1> or <2>.

According to one embodiment of the present disclosure, a pressure-sensitive adhesive composition capable of forming a pressure-sensitive adhesive layer that is not easily deformed even when cut with high temperature and is unlikely to cause unevenness in adhesive strength due to partial thickness variation. Things are provided.
According to another embodiment of the present disclosure, there is an adhesive sheet provided with an adhesive layer which is hard to be deformed even when cut with high temperature and is hard to cause unevenness of adhesive force due to partial thickness variation. Provided.
Further, according to another embodiment of the present disclosure, the optics include an adhesive layer which is hard to be deformed even when cut with high temperature and is hard to cause unevenness of adhesive force due to partial thickness variation. Members are provided.

Hereinafter, the pressure-sensitive adhesive composition, the pressure-sensitive adhesive sheet, and the optical member of the present disclosure will be described in detail. The description of the requirements set forth below may be based on the exemplary embodiments of the present disclosure, but the present disclosure is not limited to such embodiments and is within the scope of the purposes of the present disclosure. Can be implemented with appropriate changes.

The numerical range indicated by using "-" in the present disclosure means a range including the numerical values before and after "-" as the lower limit value and the upper limit value, respectively.
In the numerical range described stepwise in the present disclosure, the upper limit value or the lower limit value described in one numerical range may be replaced with the upper limit value or the lower limit value of the numerical range described in another stepwise description. Further, in the numerical range described in the present disclosure, the upper limit value or the lower limit value described in a certain numerical range may be replaced with the value shown in the examples.

In the present disclosure, a combination of two or more preferred embodiments is a more preferred embodiment.
In the present disclosure, the amount of each component in the pressure-sensitive adhesive composition is the above, which is present in the pressure-sensitive adhesive composition when a plurality of substances corresponding to each component are present in the pressure-sensitive adhesive composition, unless otherwise specified. It means the total amount of multiple substances.

In the present disclosure, the term "(meth) acrylic copolymer" means that the content of the structural unit derived from the monomer having a (meth) acryloyl group is the total structural unit [that is, the (meth) acrylic copolymer. It means a copolymer which is 50% by mass or more of [the total constituent unit of the coalescence].
In the present disclosure, the "(meth) acrylic monomer" means a monomer having a (meth) acryloyl group.

In the present disclosure, "(meth) acrylic" is a term that includes both "acrylic" and "methacrylic", and "(meth) acrylate" is a term that includes both "acrylate" and "methacrylate". "(Meta) acryloyl" is a term that includes both "acryloyl" and "methacrylic".

In the present disclosure, "n-" means normal, "i-" means iso, "s-" means secondary, and "t-" means tertiary.

In the present disclosure, "adhesive" and "adhesive composition" are synonymous.

[Adhesive composition]
The pressure-sensitive adhesive composition of the present disclosure contains a structural unit (A) derived from a monomer having a crosslinkable functional group and a structural unit (B) derived from a (meth) acrylic acid alkyl ester monomer. The content of the structural unit (A) is 0.01% by mass or more and 5% by mass or less with respect to all the structural units (meth) acrylic copolymer [hereinafter, “specific (meth) acrylic copolymer”. Also called. ], And a polyrotaxane in which the cyclic molecule has a side chain containing two or more carbon atoms and the end of the side chain is a hydroxyl group [hereinafter, also referred to as “specific polyrotaxane”. ], A cross-linking agent, and a silane coupling agent, and the content of the polyrotaxane is 20 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the (meth) acrylic copolymer. The content of the cross-linking agent is 5 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the (meth) acrylic copolymer.
According to the pressure-sensitive adhesive composition of the present disclosure, it is possible to form a pressure-sensitive adhesive layer that is not easily deformed even when cut with high temperature and is unlikely to cause unevenness in adhesive strength due to partial variation in thickness.
Although it is not clear why the pressure-sensitive adhesive composition of the present disclosure may exert such an effect, the present inventors speculate as follows. However, the following speculation does not limitly interpret the pressure-sensitive adhesive composition of the present disclosure, but is described as an example.

In the pressure-sensitive adhesive composition of the present disclosure, the following reactions are considered to occur. First, the organic group of the silane coupling agent reacts with the hydroxyl group of the specific polyrotaxane, and the silane coupling agent and the specific polyrotaxane are bonded. By this binding, the slide effect of the specific polyrotaxane is also imparted to the silane coupling agent, and the silane coupling agent having the slide effect is formed. Next, the organic group of the silane coupling agent having this sliding effect and the crosslinkable functional group of the specific (meth) acrylic copolymer are bonded via the crosslinking agent, whereby the specific polyrotaxane and the silane coupling agent are bonded. A crosslinked product is formed with the specific (meth) acrylic copolymer.
When the pressure-sensitive adhesive composition does not contain the specific (meth) acrylic copolymer, the formation of a crosslinked product between the specific (meth) acrylic copolymers is the main component, but in the pressure-sensitive adhesive composition of the present disclosure, the specific (meth) acrylic copolymer is formed. Since the content of the structural unit A derived from the monomer having a crosslinkable functional group in the above is less than or equal to a specific ratio, and because the specific polyrotaxane having a hydroxyl group is contained and the content thereof is relatively large, the silane cup is used. It is considered that the formation of a reactant between the ring agent and the specific polyrotaxane occurs preferentially. Further, if the content of the specific polyrotaxane having a hydroxyl group is too large, cross-linking between the specific polyrotaxanes rapidly occurs, and it becomes difficult to form a reactant between the specific polyrotaxane and the silane coupling agent. In the composition, since the content of the specific polyrotaxane having a hydroxyl group is not excessively large, the reaction formation between the specific polyrotaxane and the silane coupling agent is not easily impaired. Further, if the content of the cross-linking agent is too large, the cohesive force of the formed pressure-sensitive adhesive layer becomes excessively high, and the sliding effect of the specific polyrotaxane is hindered. Since the amount is less than or equal to a specific amount, the cohesive force of the formed pressure-sensitive adhesive layer does not become too high, and the sliding effect of the specific polyrotaxane is sufficiently exhibited.
According to the pressure-sensitive adhesive composition of the present disclosure, a crosslinked body having a sliding effect is formed by cross-linking the specific polyrotaxane, the silane coupling agent, and the specific (meth) acrylic copolymer, so that the thickness is partially increased. Even if there are variations, it is presumed that unevenness in the adhesive strength of the adhesive layer is unlikely to occur due to the sliding effect of the crosslinked body.

Since the pressure-sensitive adhesive composition of the present disclosure has a cross-linking agent content of a specific ratio or more with respect to the specific (meth) acrylic copolymer, a structural unit (A) derived from a monomer having a cross-linking functional group. ) Is included in the specific (meth) acrylic copolymer, which is crosslinked via a relatively large amount of a crosslinking agent. Therefore, it is presumed that the pressure-sensitive adhesive layer formed by the pressure-sensitive adhesive composition of the present disclosure has a high cohesive force and is not easily deformed even when cut with high temperature.

On the other hand, the pressure-sensitive adhesive described in Patent Document 1 (Japanese Unexamined Patent Publication No. 2011-37927) is designed to form a hard pressure-sensitive adhesive layer. Therefore, when the pressure-sensitive adhesive layer formed by the pressure-sensitive adhesive described in Patent Document 1 is attached to the uneven edge portion, the pressure-sensitive adhesive layer is hard, so that excessive stress is applied to the pressure-sensitive adhesive layer and peeling is likely to occur. It is presumed.

[Specific (meth) acrylic copolymer]
The pressure-sensitive adhesive composition of the present disclosure contains a structural unit (A) derived from a monomer having a crosslinkable functional group and a structural unit (B) derived from a (meth) acrylic acid alkyl ester monomer. A (meth) acrylic copolymer [that is, a specific (meth) acrylic copolymer] in which the content of the structural unit (A) is 0.01% by mass or more and 5% by mass or less with respect to all the structural units. include.

<Constituent unit (A)>
The specific (meth) acrylic polymer contains a structural unit (A) derived from a monomer having a crosslinkable functional group, and the content of the structural unit (A) is 0.01 with respect to all the structural units. It is by mass% or more and 5% by mass or less.

In the present disclosure, the "constituent unit derived from a monomer having a crosslinkable functional group" means a structural unit formed by addition polymerization of a monomer having a crosslinkable functional group.

Examples of the monomer having a crosslinkable functional group include a monomer having at least one crosslinkable functional group and an ethylenically unsaturated group in one molecule.
The ethylenically unsaturated group is not particularly limited.
Specific examples of the ethylenically unsaturated group include a vinyl group, an allyl group, a vinylphenyl group, a (meth) acrylamide group, and a (meth) acryloyl group.
As the ethylenically unsaturated group, a (meth) acryloyl group is preferable.

The crosslinkable functional group is not particularly limited.
Specific examples of the crosslinkable functional group include a hydroxyl group, a carboxy group, and an amino group.
The term "amino group" as used herein refers to a primary amino group and / or a secondary amino group.
The crosslinkable functional group is preferably at least one of a hydroxyl group and a carboxy group.

The type of the monomer having a hydroxyl group is not particularly limited.
Specific examples of the monomer having a hydroxyl group include 2-hydroxymethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 4-. Hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, 3-methyl-3-hydroxybutyl (meth) acrylate, 1,1 -Dimethyl-3-hydroxybutyl (meth) acrylate, 1,3-dimethyl-3-hydroxybutyl (meth) acrylate, 2,2,4-trimethyl-3-hydroxypentyl (meth) acrylate, 2-ethyl-3- Hydroxyhexyl (meth) acrylate, N-hydroxyethyl (meth) acrylamide, glycerin mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, polyethylene glycol mono (meth) acrylate, and poly (ethylene glycol-propylene glycol) mono ( Meta) acrylate can be mentioned.
As the monomer having a hydroxyl group, for example, hydroxyalkyl (meth) acrylate is preferable from the viewpoint of good copolymerizability with other monomers, and compatibility with other monomers is good. From the viewpoint and from the viewpoint of good reactivity with a cross-linking agent (particularly, an isocyanate-based cross-linking agent), a hydroxyalkyl (meth) acrylate having a hydroxyalkyl group having 1 to 5 carbon atoms is more preferable, and the hydroxyalkyl (meth) acrylate having a carbon number of 1 to 5 is more preferable. A hydroxyalkyl (meth) acrylate having 2 to 4 hydroxyalkyl groups is more preferable, and 2-hydroxyethyl acrylate (2HEA) is particularly preferable.

The type of the monomer having a carboxy group is not particularly limited.
Specific examples of the monomer having a carboxy group include acrylic acid (AA), methacrylic acid (MAA), crotonic acid, maleic anhydride, fumaric acid, itaconic acid, glutaconic acid, citraconic acid, and ω-carboxy-polycaprolactone. Mono (meth) acrylate [eg, ω-carboxy-polycaprolactone (n≈2) monoacrylate], succinic acid ester (eg, 2-acryloyloxyethyl-succinic acid), vinyl formate, vinyl acetate, vinyl propionate, and Examples include vinyl neodecanoate.
As the monomer having a carboxy group, acrylic acid (AA) is preferable, for example, from the viewpoint of good reactivity with a cross-linking agent (particularly, an isocyanate-based cross-linking agent).

The type of the monomer having an amino group is not particularly limited.
Specific examples of the monomer having a primary amino group include acrylamide and methacrylamide.
Specific examples of the monomer having a secondary amino group include N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, and N-methoxyethyl (meth) acrylamide.

The specific (meth) acrylic polymer may contain only one type of the structural unit (A), or may contain two or more types.

The content of the structural unit (A) in the specific (meth) acrylic copolymer is 0.01% by mass or more and 5% by mass or less with respect to all the structural units of the specific (meth) acrylic copolymer.
When the content of the structural unit (A) in the specific (meth) acrylic copolymer is 0.01% by mass or more with respect to all the structural units of the specific (meth) acrylic copolymer, cutting with high temperature is accompanied. There is a tendency that it is possible to form a pressure-sensitive adhesive layer that is not easily deformed and is unlikely to cause unevenness in the pressure-sensitive adhesive force due to a partial variation in thickness. From this point of view, the content of the structural unit (A) in the specific (meth) acrylic copolymer is 0.01% by mass or more with respect to all the structural units of the specific (meth) acrylic copolymer. It is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, further preferably 0.5% by mass or more, and particularly preferably 1% by mass or more. ..
When the content of the structural unit (A) in the specific (meth) acrylic copolymer is 5% by mass or less with respect to all the structural units of the specific (meth) acrylic copolymer, the partial thickness variation There is a tendency to be able to form an adhesive layer in which unevenness in the adhesive force due to the above is unlikely to occur. From this point of view, the content of the structural unit (A) in the specific (meth) acrylic copolymer is 5% by mass or less with respect to all the structural units of the specific (meth) acrylic copolymer. It is preferably 4.5% by mass or less, more preferably 4% by mass or less, further preferably 3.5% by mass or less, and particularly preferably 3% by mass or less.

<Constituent unit (B)>
The specific (meth) acrylic copolymer contains a structural unit (B) derived from the (meth) acrylic acid alkyl ester monomer.
The structural unit (B) contributes to the adjustment of the adhesive strength of the pressure-sensitive adhesive layer.

In the present disclosure, the "constituent unit derived from the (meth) acrylic acid alkyl ester monomer" means a structural unit formed by addition polymerization of the (meth) acrylic acid alkyl ester monomer.
The "(meth) acrylic acid alkyl ester monomer" in the present disclosure does not include a monomer corresponding to a monomer having a crosslinkable functional group.

The type of the (meth) acrylic acid alkyl ester monomer is not particularly limited.
The (meth) acrylic acid alkyl ester monomer is preferably an unsubstituted (meth) acrylic acid alkyl ester monomer.
Further, the (meth) acrylic acid alkyl ester monomer may be a methacrylic acid alkyl ester monomer or an acrylic acid alkyl ester monomer, and may be, for example, the above-mentioned crosslinkable functional group. Acrylic acid alkyl ester monomer is preferable from the viewpoint of good copolymerizability with the monomer having.
The alkyl group of the (meth) acrylic acid alkyl ester monomer may be linear, branched or cyclic.

The number of carbon atoms of the alkyl group is, for example, preferably 1 to 18 and more preferably 1 to 12 from the viewpoint of forming a pressure-sensitive adhesive layer having excellent adhesion to a substrate.

Specific examples of the (meth) acrylic acid alkyl ester monomer include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, and s-butyl (meth). Acrylate, t-butyl (meth) acrylate, n-octyl (meth) acrylate, i-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-nonyl (meth) acrylate, i-nonyl (meth) acrylate, Examples thereof include n-decyl (meth) acrylate, stearyl (meth) acrylate, lauryl (meth) acrylate, cyclohexyl (meth) acrylate, and isobornyl (meth) acrylate.
As the (meth) acrylic acid alkyl ester monomer, at least one selected from n-butyl acrylate (n-BA) and 2-ethylhexyl acrylate (2EHA) is preferable, and n-butyl acrylate (n-BA) is more preferable. preferable.

The specific (meth) acrylic copolymer may contain only one type of the structural unit (B), or may contain two or more types.

The content of the structural unit (B) in the specific (meth) acrylic copolymer is not particularly limited, but is, for example, 50% by mass or more with respect to all the structural units of the specific (meth) acrylic copolymer. It is preferably 50% by mass to 99.99% by mass, more preferably 60% by mass to 99.9% by mass, and particularly preferably 70% by mass to 99.9% by mass. preferable.
Here, it is a constituent unit that the content of the constituent unit (B) in the specific (meth) acrylic copolymer is 50% by mass or more with respect to all the constituent units of the specific (meth) acrylic copolymer. It means that (B) is contained as a main component of the structural unit constituting the specific (meth) acrylic copolymer.

<Other building blocks>
The specific (meth) acrylic copolymer contains structural units (so-called other structural units) other than the above-mentioned structural units, if necessary, as long as the effects of the pressure-sensitive adhesive composition of the present disclosure are not impaired. be able to.

Examples of the monomers constituting other structural units include (meth) acrylate having an aromatic ring represented by benzyl (meth) acrylate and phenoxyethyl (meth) acrylate, methoxyethyl (meth) acrylate and ethoxyethyl. Alkoxyalkyl (meth) acrylate represented by (meth) acrylate, styrene, α-methylstyrene, t-butylstyrene, p-chlorostyrene, chloromethylstyrene, and aromatic monovinyl, acrylonitrile and methacrylic represented by vinyltoluene. Examples thereof include vinyl cyanide typified by acrylonitrile, and vinyl esters typified by vinyl acrylate, vinyl acetate, vinyl propionate, and vinyl versatic acid. In addition, various derivatives of these monomers can be mentioned.

When the specific (meth) acrylic copolymer contains other structural units, it may contain only one type of other structural units, or may contain two or more types of other structural units.

When the specific (meth) acrylic copolymer contains other structural units, the content of the other structural units in the specific (meth) acrylic copolymer is not particularly limited and can be appropriately set according to the purpose. ..

<< Glass transition temperature of specific (meth) acrylic copolymer >>
The glass transition temperature (also referred to as “Tg”) of the specific (meth) acrylic copolymer is not particularly limited, but is preferably, for example, less than 0 ° C, more preferably −20 ° C or lower. It is more preferably −30 ° C. or lower, and particularly preferably −40 ° C. or lower.
When the glass transition temperature of the specific (meth) acrylic copolymer is less than 0 ° C., it tends to be possible to form a pressure-sensitive adhesive layer in which unevenness in adhesive strength due to partial thickness variation is unlikely to occur.
The lower limit of the glass transition temperature of the specific (meth) acrylic copolymer is preferably −70 ° C. or higher, for example.

For the glass transition temperature of the specific (meth) acrylic copolymer, the absolute temperature (unit: K; hereinafter the same) calculated from the following formula 1 is changed to the Kelvin temperature (unit: ° C; hereinafter the same). It is a converted value.
1 / Tg = m1 / Tg1 + m2 / Tg2 + ... + m (k-1) / Tg (k-1) + mk / Tgk (Equation 1)

In the formula 1, Tg1, Tg2, ..., Tg (k-1), and Tgk are used when each monomer constituting the specific (meth) acrylic copolymer (A) is used as a homopolymer. Each represents the glass transition temperature expressed in absolute temperature. m1, m2, ..., m (k-1), and mk represent the mole fractions of each monomer constituting the specific (meth) acrylic copolymer, respectively, and m1 + m2 + ... + m (k). -1) + mk = 1.
The absolute temperature can be converted to the Celsius temperature by subtracting 273 from the absolute temperature, and the Celsius temperature can be converted to the absolute temperature by adding 273 to the Celsius temperature.

In the present disclosure, the "glass transition temperature represented by the absolute temperature when made into a homopolymer" is the glass transition temperature represented by the absolute temperature of the homopolymer produced by polymerizing the monomer alone. To say.
The glass transition temperature of the homopolymer was measured using a differential scanning calorimetry device (DSC) [model number: EXSTAR6000, manufactured by Seiko Instruments Co., Ltd.] under the conditions of a measurement sample of 10 mg and a temperature rise rate of 10 ° C./min in a nitrogen stream. The turning point of the obtained DSC curve was taken as the glass transition temperature of the homopolymer.

The "glass transition temperature represented by the Celsius temperature when made into a homopolymer" of a typical monomer is -76 ° C for 2-ethylhexyl acrylate (2EHA) and -10 ° C for 2-ethylhexyl methacrylate (2EHMA). , N-butyl acrylate (n-BA) is −57 ° C., n-butyl methacrylate (n-BMA) is 21 ° C., t-butyl acrylate (t-BA) is 41 ° C., t-butyl methacrylate (t-BMA). 107 ° C, i-butyl methacrylate (i-BMA) 48 ° C, methyl acrylate (MA) 5 ° C, methyl methacrylate (MMA) 103 ° C, isobonyl methacrylate (IBXMA) 155 ° C, isobonyl acrylate (IBXA). ) Is 96 ° C, ethyl acrylate (EA) is -27 ° C, methacrylic acid is 185 ° C, 4-hydroxybutyl acrylate (4HBA) is -39 ° C, 2-hydroxyethyl acrylate (2HEA) is -15 ° C, 2-hydroxy. Ethyl methacrylate (2HEMA) at 55 ° C, 2-hydroxypropyl acrylate (2HPA) at -7 ° C, acrylic acid (AA) at 163 ° C, i-octyl acrylate (i-OA) at -75 ° C, dimethylaminoethyl methacrylate ( DM) is 18 ° C., ω-carboxy-polycaprolactone (n≈2) monoacrylate is −30 ° C., and 2-acryloyloxyethyl-succinic acid is −40 ° C.

The glass transition temperature of the specific (meth) acrylic copolymer can be appropriately adjusted by using, for example, two or more kinds of monomers having different glass transition temperatures when used as a homopolymer.

<< Weight average molecular weight of specific (meth) acrylic copolymer >>
The weight average molecular weight (also referred to as “Mw”) of the specific (meth) acrylic copolymer is not particularly limited, but is preferably 500,000 to 2.5 million, preferably 600,000 to 2 million, for example. More preferably, it is more preferably 700,000 to 1.8 million, and particularly preferably 800,000 to 1.7 million.
When the weight average molecular weight of the specific (meth) acrylic copolymer is 500,000 or more, there is a tendency that a pressure-sensitive adhesive layer that is less likely to be deformed can be formed even when cutting is performed with high temperature.
When the weight average molecular weight of the specific (meth) acrylic copolymer is 2.5 million or less, it tends to be possible to form a pressure-sensitive adhesive layer in which unevenness in adhesive strength due to partial thickness variation is less likely to occur.

The weight average molecular weight of the specific (meth) acrylic copolymer is a value measured by the following method. Specifically, the measurement is performed according to the following (1) to (3).
(1) A solution of the specific (meth) acrylic copolymer is applied to a release paper and dried at 100 ° C. for 1 minute to obtain a film-like specific (meth) acrylic copolymer.
(2) Using the film-shaped specific (meth) acrylic copolymer obtained in (1) above and tetrahydrofuran is used to obtain a sample solution having a solid content concentration of 0.2% by mass. The "solid content concentration" here means the mass ratio of the specific (meth) acrylic copolymer to the sample solution.
(3) Using gel permeation chromatography (GPC), the weight average molecular weight of the specific (meth) acrylic copolymer is measured as a standard polystyrene-equivalent value under the following conditions.

~ Conditions ~
Measuring device: High-speed GPC [Model number: HLC-8220 GPC, manufactured by Tosoh Corporation]
Detector: Differential refractometer (RI) [Built-in to HLC-8220, manufactured by Tosoh Corporation]
Column: Uses 4 TSKgel GMH _XL [Tosoh Corporation] Column temperature: 40 ° C
Eluent: Tetrahydrofuran Sample solution injection volume: 100 μL
Flow rate: 0.8 mL / min

The weight average molecular weight of the specific (meth) acrylic copolymer can be set to a desired value by adjusting the polymerization temperature, polymerization time, amount of organic solvent used, type of polymerization initiator, amount of polymerization initiator used, and the like. can.

<< Content of specific (meth) acrylic copolymer >>
The content of the specific (meth) acrylic copolymer in the pressure-sensitive adhesive composition of the present disclosure is not particularly limited, but is, for example, 50% by mass to 80% by mass with respect to the total solid content in the pressure-sensitive adhesive composition. It is preferably 60% by mass to 80% by mass, more preferably 65% by mass to 80% by mass, and particularly preferably 65% by mass to 75% by mass.
In the present disclosure, the "total solid content in the pressure-sensitive adhesive composition" means the total mass of the pressure-sensitive adhesive composition when the pressure-sensitive adhesive composition does not contain a solvent, and the pressure-sensitive adhesive composition contains a solvent. In the case of, it means the mass of the residue obtained by removing the solvent from the pressure-sensitive adhesive composition.
In the present disclosure, "solvent" means water and an organic solvent.

[Manufacturing method of specific (meth) acrylic copolymer]
The method for producing the specific (meth) acrylic copolymer is not particularly limited.
The specific (meth) acrylic copolymer is obtained by polymerizing the above-mentioned monomer by a known polymerization method typified by, for example, a solution polymerization method, an emulsion polymerization method, a suspension polymerization method, and a bulk polymerization method. Can be manufactured by
As a polymerization method, a solution polymerization method is preferable because the treatment step is relatively simple and can be performed in a short time in preparing the pressure-sensitive adhesive composition of the present disclosure after production.

In the solution polymerization method, a predetermined organic solvent, a monomer, a polymerization initiator, and a chain transfer agent used as needed are generally charged in a polymerization tank, for example, in a nitrogen stream at the reflux temperature of the organic solvent. , Heat reaction for several hours with stirring. In this case, at least a part of the organic solvent, the monomer, the polymerization initiator and / or the chain transfer agent may be added sequentially.

Examples of the organic solvent used in the polymerization reaction include aromatic hydrocarbon compounds, aliphatic or alicyclic hydrocarbon compounds, ester compounds, ketone compounds, glycol ether compounds, alcohol compounds and the like.
More specifically, examples of the organic solvent used in the polymerization reaction include benzene, toluene, ethylbenzene, n-propylbenzene, t-butylbenzene, o-xylene, m-xylene, p-xylene, tetraline and decalin. And aromatic hydrocarbon compounds typified by aromatic naphtha, n-hexane, n-heptane, n-octane, i-octane, n-decane, dipentene, petroleum spirit, petroleum naphtha, and fat typified by terepine oil. Represented by group or alicyclic hydrocarbon compounds, ethyl acetate, n-butyl acetate, n-amyl acetate, 2-hydroxyethyl acetate, 2-butoxyethyl acetate, 3-methoxybutyl acetate, and methyl benzoate. Ester compounds, acetone, methyl ethyl ketone, methyl-i-butyl ketone, isophorone, cyclohexanone, and ketone compounds typified by methylcyclohexanone, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl. Glycol ether compounds typified by ether and diethylene glycol monobutyl ether, as well as methyl alcohol, ethyl alcohol, n-propyl alcohol, i-propyl alcohol, n-butyl alcohol, i-butyl alcohol, s-butyl alcohol, and t- Examples thereof include alcohol compounds typified by butyl alcohol.

In the production of the specific (meth) acrylic copolymer, it is preferable to use an organic solvent that does not easily cause chain transfer during the polymerization reaction of aromatic hydrocarbon compounds, ester compounds, ketone compounds and the like, and in particular, the specific (meth) acrylic. From the viewpoint of solubility of the system copolymer, ease of polymerization reaction and the like, it is preferable to use ethyl acetate.

At the time of the polymerization reaction, only one kind of organic solvent may be used, or two or more kinds may be used.

Examples of the polymerization initiator include organic peroxides and azo compounds used in ordinary solution polymerization methods.
Examples of the organic peroxide include t-butyl hydroperoxide, cumene hydroperoxide, dicumyl peroxide, benzoyl peroxide, lauroyl peroxide, caproyl peroxide, di-i-propylperoxydicarbonate, and di-2-ethylhexylperoxydi. Carbonate, t-butylperoxypivalate, 2,2-bis (4,4-di-t-butylperoxycyclohexyl) propane, 2,2-bis (4,4-di-t-amylperoxycyclohexyl) propane, 2,2-bis (4,4-di-t-octylperoxycyclohexyl) propane, 2,2-bis (4,4-di-α-cumylperoxycyclohexyl) propane, 2,2-bis (4,4) -Di-t-butylperoxycyclohexyl) butane and 2,2-bis (4,4-di-t-octylperoxycyclohexyl) butane can be mentioned.
Examples of the azo compound include 2,2'-azobisisobutyronitrile [AIBN], 2,2'-azobis (2,4-dimethylvaleronitrile) [ABVN], and 2,2'-azobis (4-). Methoxy-2,4-dimethylvaleronitrile), 1,1'-azobis (cyclohexane-1-carbonitrile), and 2,2'-azobis (isobutyric acid) dimethyl.
In the production of the specific (meth) acrylic copolymer, it is preferable to use a polymerization initiator that does not cause a graft reaction during the polymerization reaction, and it is particularly preferable to use an azo compound.

At the time of the polymerization reaction, only one kind of polymerization initiator may be used, or two or more kinds of polymerization initiators may be used.

The amount of the polymerization initiator used is not particularly limited, and can be appropriately set, for example, according to the molecular weight of the specific (meth) acrylic copolymer of interest.

A chain transfer agent may be used in the production of the specific (meth) acrylic copolymer, if necessary.
Examples of the chain transfer agent include cyanoacetic acid, an alkyl ester compound having 1 to 8 carbon atoms of cyanoacetic acid, bromoacetic acid, an alkyl ester compound having 1 to 8 carbon atoms of bromoacetic acid, α-methylstyrene, anthracene, phenanthrene, and fluorene. , And aromatic compounds such as 9-phenylfluorene, p-nitroaniline, nitrobenzene, dinitrobenzene, p-nitrobenzoic acid, p-nitrophenol, and aromatic nitro compounds such as p-nitrotoluene, benzoquinone and Benzoquinone derivatives typified by 2,3,5,6-tetramethyl-p-benzoquinone, borane derivatives typified by tributylborane, carbon tetrabromide, carbon tetrachloride, 1,1,2,2-tetrabromoethane , Tribromoethylene, trichloroethylene, bromotrichloromethane, tribromomethane, and halogenated hydrocarbon compounds typified by 3-chloro-1-propene, aldehyde compounds typified by chloral and furaldehyde, alkyl having 1 to 18 carbon atoms. For mercaptan compounds, aromatic mercaptan compounds typified by thiophenol and toluene mercaptan, mercaptoacetic acid, alkyl ester compounds having 1 to 10 carbon atoms of mercaptoacetic acid, hydroxyalkyl mercaptan compounds having 1 to 12 carbon atoms, and pinen and turpinolene. Representative terpene compounds can be mentioned.

When a chain transfer agent is used in the production of the specific (meth) acrylic copolymer, the amount of the chain transfer agent used is not particularly limited, and is, for example, the molecular weight of the target specific (meth) acrylic copolymer. It can be set as appropriate.

The polymerization temperature is not particularly limited, and can be appropriately set, for example, according to the molecular weight of the target specific (meth) acrylic copolymer.

[Specific polyrotaxane]
The pressure-sensitive adhesive composition of the present disclosure comprises a polyrotaxane (that is, a specific polyrotaxane) in which a cyclic molecule has a side chain containing two or more carbon atoms and the end of the side chain is a hydroxyl group, and the specific polyrotaxane is contained. The amount is 20 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the above-mentioned specific (meth) acrylic copolymer.

Polyrotaxane is a compound consisting of a cyclic molecule, a linear molecule that penetrates the opening of the cyclic molecule in a skewered manner, and a blocking group that seals both ends of the linear molecule.
The specific polyrotaxane has a structure in which the cyclic molecule of the polyrotaxane has a side chain containing two or more carbon atoms, and the end of the side chain is a hydroxyl group.
Hereinafter, "a cyclic molecule having a side chain containing two or more carbon atoms and having a hydroxyl group at the end of the side chain" is also referred to as a "specific cyclic molecule". Further, the "cyclic molecule forming a specific cyclic molecule" is also simply referred to as a "cyclic molecule".
The specific polyrotaxane may contain one specific cyclic molecule or two or more specific cyclic molecules.

The cyclic molecule is not particularly limited as long as it can be included in the opening so that the linear molecule penetrates in a skewered manner and can move on the linear molecule.
As a method for encapsulating the cyclic molecule with the linear molecule, a conventionally known method (for example, the method described in JP-A-2005-154675) can be used.
In the present disclosure, the term "cyclic" of a cyclic molecule means that it is substantially cyclic and may not be a completely ring-closed structure as long as it is mobile on a linear molecule, eg, a helix. It may be a structure.

Specific examples of the cyclic molecule include cyclic polymers such as cyclic polyethers, cyclic polyesters and cyclic polyether amines, and cyclodextrins such as α-cyclodextrin, β-cyclodextrin and γ-cyclodextrin.
Among these, as the cyclic molecule, for example, cyclodextrins such as α-cyclodextrin, β-cyclodextrin, and γ-cyclodextrin are relatively easy to obtain and a large number of types of blocking groups can be selected. Is preferable.

The cyclic molecule is appropriately selected depending on the type of the linear molecule.
For example, when polyethylene glycol is selected as the linear molecule, the cyclic molecule is either α-cyclodextrin, β-cyclodextrin, or γ-cyclodextrin from the viewpoint of the stability of the resulting inclusion. Is preferable.

It is preferable that the cyclic molecule has a substituent that can contribute to the improvement of compatibility with the specific (meth) acrylic copolymer.
Examples of such a substituent include a polyester chain and an oxyalkylene chain. Only one of these substituents may be introduced, or two or more of these substituents may be introduced, and it is preferable that a polyester chain and an oxyethylene chain are introduced.
These substituents are described in paragraphs [0011] to [0013] of Japanese Patent No. 6258228. These statements are incorporated herein by reference. However, in these descriptions, "radical polymerizable group" shall be read as "hydroxyl group", and "polymerizable monomer" shall be read as "specific (meth) acrylic copolymer".

The specific polyrotaxane contains a cyclic molecule (that is, a specific cyclic molecule) having a side chain containing two or more carbon atoms and having a hydroxyl group at the end of the side chain.
The number of carbon atoms contained in the side chain is 2 or more, preferably 5 or more, more preferably 8 or more, and even more preferably 13 or more.
The upper limit of the number of carbon atoms contained in the side chain is not particularly limited, but is preferably 60,000 or less, for example.

A linear molecule is a molecule or substance that is skewered into the opening of a cyclic molecule and can be integrated with the cyclic molecule by mechanical bonds rather than chemical bonds (eg, covalent bonds). It is not particularly limited as long as it has a shape.
In the present disclosure, the "linearity" of a linear molecule means that it is substantially linear, and if the cyclic molecule is migratory on the linear molecule, then the linear molecule is a branched chain. May have.

Specific examples of the linear molecule include polyethylene glycol, polypropylene glycol, polyisoprene, polyisobutylene, polybutadiene, polytetrahydrofuran, polyacrylic acid ester, polydimethylsiloxane, polyethylene, and polypropylene.
Among these, polyethylene glycol is preferable as the linear molecule.
Specific examples of the linear molecule are described in paragraph [0018] of Japanese Patent No. 6258228. This description is incorporated herein by reference.

The weight average molecular weight of the linear molecule is preferably 3000 or more, more preferably 5000 or more, and further preferably 10,000 or more.
When the weight average molecular weight of the linear molecule is 3000 or more, the amount of the cyclic molecule moving on the linear molecule becomes larger, so that the specific polyrotaxane, the silane coupling agent, and the specific (meth) acrylic copolymer There is a tendency that the sliding effect of a crosslinked body having a sliding effect, which is crosslinked with and, is more likely to be exhibited. Therefore, there is a tendency to form an adhesive layer in which unevenness in the adhesive force due to the partial variation in thickness is less likely to occur.
The weight average molecular weight of the linear molecule is preferably 300,000 or less, more preferably 100,000 or less, and further preferably 50,000 or less.
When the weight average molecular weight of the linear molecule is 300,000 or less, the compatibility between the specific polyrotaxane and the above-mentioned specific (meth) acrylic copolymer can be further improved.
The weight average molecular weight of the linear molecule is a value measured as a polyethylene glycol equivalent value using gel permeation chromatography (GPC). As the column, TSKgel SuperAWM-H manufactured by Tosoh Corporation can be used.

The blocking group is arranged at both ends of the linear molecule in which the cyclic molecule is encapsulated, and has a role of acting to prevent the cyclic molecule from being detached.
As a method for sealing both ends of the linear molecule with a blocking group, a conventionally known method (for example, the method described in JP-A-2005-154675) can be used.

Specific examples of the blocking group include a dinitrophenyl group, an adamantyl group, and a trityl group. Both ends of the linear molecule may be sealed with different blocking groups.
As the blocking group of the specific polyrotaxane, an adamantyl group is preferable.
Specific examples of the blocking group are described in paragraph [0022] of Japanese Patent No. 6258228. This description is incorporated herein by reference.

When the cyclic molecule encapsulates the linear molecule, the ratio of the amount of the linear molecule to be encapsulated by the cyclic molecule is 0 when the maximum inclusion amount (maximum inclusion amount) is 100%. .1% to 60%, more preferably 1% to 50%, still more preferably 5% to 40%.
The maximum inclusion amount is determined by the length of the linear molecule and the thickness of the cyclic molecule. For example, the maximum inclusion amount when the linear molecule is polyethylene glycol and the cyclic molecule is α-cyclodextrin has been experimentally determined (see Macromolecules 1993, 26, 5698-5703).

In a preferred embodiment of the specific polyrotaxane, the cyclic molecule is a molecule derived from α-cyclodextrin, the linear molecule is polyethylene glycol, the blocking group is an adamantan group, and one of the hydroxyl groups derived from glucose of α-cyclodextrin. The part is reacting with the carboxy group of the ring-opened lactone compound, or is substituted with a hydroxypropyl group, and the hydroxyl group of the hydroxypropyl group is reacting with the carboxy group of the ring-opened lactone compound. This embodiment has a hydroxyl group derived from an opened lactone compound at the end of the side chain.

The weight average molecular weight of the specific polyrotaxane is preferably 100,000 or more, more preferably 150,000 or more, and further preferably 200,000 or more.
The weight average molecular weight of the specific polyrotaxane is preferably 1 million or less, more preferably 900,000 or less, and further preferably 800,000 or less.
The weight average molecular weight of the specific polyrotaxane is a value measured as a polystyrene-equivalent value using gel permeation chromatography (GPC). As the column, TSKgel SuperHM-M manufactured by Tosoh Corporation can be used.

The hydroxyl value of the specific polyrotaxane is preferably 40 mgKOH / g or more, more preferably 50 mgKOH / g or more, and even more preferably 60 mgKOH / g or more.
The hydroxyl value of the specific polyrotaxane is preferably 100 mgKOH / g or less, more preferably 90 mgKOH / g or less, and even more preferably 80 mgKOH / g or less.
The hydroxyl value of the specific polyrotaxane is a value measured by a method according to JIS K 0070: 1992.

The specific polyrotaxane can be obtained, for example, by the methods described in JP-A-2005-154675, JP-A-2009-270119, and International Publication No. 2009/145573.
The specific polyrotaxane is also available as a commercial product.
As an example of a commercially available product of the specific polyrotaxane, "SELM (registered trademark) Superpolymer SH3400P" manufactured by ASM Co., Ltd. [Overall weight average molecular weight: 700,000, linear molecule weight average molecular weight: 35,000, Hydroxyl value: 72 mgKOH / g], "SELM (registered trademark) Superpolymer SH2400P" [overall weight average molecular weight: 400,000, linear molecular weight average molecular weight: 20,000, hydroxyl value: 76 mgKOH / g], and " SELM® Superpolymer SH1300P ”[total weight average molecular weight: 180,000, linear molecular weight average molecular weight: 11,000, hydroxyl value: 85 mgKOH / g].

The pressure-sensitive adhesive composition of the present disclosure may contain only one type of specific polyrotaxane, or may contain two or more types.

The content of the specific polyrotaxane in the pressure-sensitive adhesive composition of the present disclosure is 20 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the specific (meth) acrylic copolymer.
When the content of the specific polyrotaxane in the pressure-sensitive adhesive composition of the present disclosure is within the above range with respect to 100 parts by mass of the specific (meth) acrylic copolymer, the adhesive strength due to the partial thickness variation There is a tendency to form an adhesive layer that is less likely to cause unevenness.
The content of the specific polyrotaxane in the pressure-sensitive adhesive composition of the present disclosure is preferably 23 parts by mass or more, and more preferably 25 parts by mass or more with respect to 100 parts by mass of the specific (meth) acrylic copolymer. , 28 parts by mass or more, and particularly preferably 30 parts by mass or more.
Further, the content of the specific polyrotaxane in the pressure-sensitive adhesive composition of the present disclosure is preferably 48 parts by mass or less, preferably 45 parts by mass or less, based on 100 parts by mass of the specific (meth) acrylic copolymer. Is more preferable, and it is further preferably 43 parts by mass or less, and particularly preferably 40 parts by mass or less.

[Crosslinking agent]
The pressure-sensitive adhesive composition of the present disclosure contains a cross-linking agent, and the content of the cross-linking agent is 5 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the above-mentioned specific (meth) acrylic copolymer. ..
In the pressure-sensitive adhesive composition of the present disclosure, the cross-linking agent is hard to be deformed even when cut with high temperature, and it is difficult to cause unevenness of the pressure-sensitive adhesive force due to partial thickness variation. Contribute.
The type of the cross-linking agent is not particularly limited.
Examples of the cross-linking agent include an isocyanate-based cross-linking agent, an epoxy-based cross-linking agent, and a metal chelate-based cross-linking agent.
Among these, as the cross-linking agent, a cross-linking agent having good reactivity with a hydroxyl group is preferable, and an isocyanate-based cross-linking agent is more preferable.

In the present disclosure, the "isocyanate-based cross-linking agent" refers to a compound having two or more isocyanate groups in one molecule (so-called polyisocyanate compound). Further, the "epoxy-based cross-linking agent" refers to a compound having two or more epoxy groups in one molecule (so-called bifunctional or higher epoxy compound). Further, the "metal chelate-based cross-linking agent" refers to a metal chelate compound that functions as a cross-linking agent.

The type of isocyanate-based cross-linking agent is not particularly limited.
Examples of the isocyanate-based cross-linking agent include aromatic polyisocyanate compounds such as xylylene diisocyanate (XDI), diphenylmethane diisocyanate, triphenylmethane triisocyanate, and tolylene diisocyanate (TDI), hexamethylene diisocyanate (HMDI), and pentamethylene diisocyanate (PDI). ), Isophoron diisocyanate, aliphatic or alicyclic polyisocyanate compounds such as hydrogenated additives of aromatic polyisocyanate compounds, and the like.
Examples of the isocyanate-based cross-linking agent include a dimer, a trimer, or a pentamer of the polyisocyanate compound, an adduct of the polyisocyanate compound and a polyol compound such as trimethylolpropane, and a biuret of the polyisocyanate compound. The body is also mentioned.

As the isocyanate-based cross-linking agent, a commercially available product can be used.
Examples of commercially available isocyanate-based cross-linking agents are "Coronate (registered trademark) HX", "Coronate (registered trademark) HL-S", "Coronate (registered trademark) L", and "Coronate (registered trademark) L-45E". , "Coronate® 2031", "Coronate® 2030", "Coronate® 2234", "Coronate® 2785", "Aquanate® 200", and " Aquanate (registered trademark) 210 "[above, manufactured by Toso Co., Ltd.]," Sumijuru (registered trademark) N3300 "," Death Module (registered trademark) N3400 ", and" Sumijuru (registered trademark) N75 "[more than , Sumika Cobestro Urethane Co., Ltd.], "Duranate (registered trademark) E-405-80T", "Duranate (registered trademark) AE700-100", "Duranate (registered trademark) 24A-100", and "Duranate" (Registered Trademark) TSE-100 "[above, manufactured by Asahi Kasei Co., Ltd.]," Takenate (registered trademark) D-110N "," Takenate (registered trademark) D-120N "," Takenate (registered trademark) M- 631N ”,“ MT-Orester® NP1200 ”, and“ Stavio® XD-340N ”[above, manufactured by Mitsui Kagaku Co., Ltd.].

The type of the epoxy-based cross-linking agent is not particularly limited.
Examples of the epoxy-based cross-linking agent include ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, and the like. 1,6-Hexanediol diglycidyl ether, polytetramethylene glycol diglycidyl ether, glycerol diglycidyl ether, glycerol triglycidyl ether, diglycerol polyglycidyl ether, polyglycerol polyglycidyl ether, resorcin diglycidyl ether, 2,2-dibromo Neopentyl glycol diglycidyl ether, trimethylolpropane triglycidyl ether, pentaerythritol polyglycidyl ether, sorbitol polyglycidyl ether, adipate diglycidyl ester, phthalic acid diglycidyl ester, tris (glycidyl) isocyanurate, tris (glycidoxyethyl) ) Isocyanurate, 1,3-bis (N, N-glycidylaminomethyl) cyclohexane, N, N, N', N'-tetraglycidyl-1,3-benzenedi (methaneamine) and the like.

As the epoxy-based cross-linking agent, a commercially available product can be used.
Examples of commercially available epoxy-based cross-linking agents include "TETRAD (registered trademark) -X" and "TETRAD (registered trademark) -C" [all manufactured by Mitsubishi Gas Chemical Company, Inc.].

The type of the metal chelate-based cross-linking agent is not particularly limited.
Examples of the metal chelate-based cross-linking agent include aluminum monoacetylacetonate bis (ethylacetate acetate), aluminumtris (ethylacetacetate), and aluminum chelate compounds typified by aluminumtris (acetylacetonate), titanium chelate compounds, and zirconium chelate. Examples thereof include compounds and cobalt chelate compounds.

As the metal chelate-based cross-linking agent, a commercially available product can be used.
Examples of commercially available metal chelate-based cross-linking agents are aluminum chelate A [trade name, aluminum tris (acetylacetoneate), manufactured by Kawaken Fine Chemical Co., Ltd.], aluminum chelate D [trade name, aluminum monoacetylacetonate bis. (Ethylacetacetate), manufactured by Kawaken Fine Chemical Co., Ltd.], and ALCH-TR [trade name, aluminum tris (ethylacetate acetate), manufactured by Kawaken Fine Chemical Co., Ltd.].

The pressure-sensitive adhesive composition of the present disclosure may contain only one kind of cross-linking agent, or may contain two or more kinds of cross-linking agents.

The content of the cross-linking agent in the pressure-sensitive adhesive composition of the present disclosure is 5 parts by mass or more and 50 parts by mass or more with respect to 100 parts by mass of the specific (meth) acrylic copolymer.
When the content of the cross-linking agent in the pressure-sensitive adhesive composition of the present disclosure is 5 parts by mass or more with respect to 100 parts by mass of the specific (meth) acrylic copolymer, it is difficult to be deformed even when cutting with high temperature is performed. It tends to form a pressure-sensitive adhesive layer. From such a viewpoint, the content of the cross-linking agent in the pressure-sensitive adhesive composition of the present disclosure is 5 parts by mass or more and 6 parts by mass or more with respect to 100 parts by mass of the specific (meth) acrylic copolymer. Is more preferable, and it is more preferably 7 parts by mass or more, and further preferably 8 parts by mass or more.
When the content of the cross-linking agent in the pressure-sensitive adhesive composition of the present disclosure is 50 parts by mass or more with respect to 100 parts by mass of the specific (meth) acrylic copolymer, the pressure-sensitive adhesive strength due to the partial thickness variation There is a tendency to form an adhesive layer that is less likely to cause unevenness. From such a viewpoint, the content of the cross-linking agent in the pressure-sensitive adhesive composition of the present disclosure is 50 parts by mass or less and 40 parts by mass or less with respect to 100 parts by mass of the specific (meth) acrylic copolymer. Is more preferable, and it is more preferably 30 parts by mass or less, and further preferably 20 parts by mass or less.

〔Silane coupling agent〕
The pressure-sensitive adhesive composition of the present disclosure comprises a silane coupling agent.
In the pressure-sensitive adhesive composition of the present disclosure, the silane coupling agent contributes to the formation of a pressure-sensitive adhesive layer in which unevenness in adhesive strength due to partial thickness variation is unlikely to occur.

The silane coupling agent is not particularly limited.
Examples of the silane coupling agent include vinyltrimethoxysilane, vinyltriethoxysilane, and a polymerizable unsaturated group-containing silane compound typified by 3-methacryloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3 -Mercaptopropyltriethoxysilane and thiol group-containing silane compounds typified by 3-mercaptopropyldimethoxymethylsilane, 3-glycidoxypropyltrimethoxysilane and 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane. Epoxy group-containing silane compounds typified by, 3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, and N- (2-aminoethyl) -3-aminopropylmethyl. Examples thereof include an amino group-containing silane compound typified by dimethoxysilane and an isocyanurate group-containing silane compound typified by tris- (3-trimethoxysilylpropyl) isocyanurate.

As the silane coupling agent, a commercially available product can be used.
Examples of commercially available silane coupling agents include thiol group-containing silane compounds "KBM-803", "KBM-802", "X-41-1810", "X-41-1811", and "X-". 41-1805 "and" X-41-1818 ", epoxy group-containing silane compounds" KBM-403 "," KBM-303 "," KBM-402 "," KBE-402 "," KBE-403 ". , "X-41-1053" and "X-41-1056", amino group-containing silane compounds "KBM-573" and "KBM-903", and isocyanurate group-containing silane compound "KBM-". 9659 "[both trade names, manufactured by Shin-Etsu Chemical Industry Co., Ltd.] can be mentioned.

The pressure-sensitive adhesive composition of the present disclosure may contain only one kind of silane coupling agent, or may contain two or more kinds of silane coupling agents.

The content of the silane coupling agent in the pressure-sensitive adhesive composition of the present disclosure is not particularly limited, but is, for example, 0.1 part by mass to 1 part by mass with respect to 100 parts by mass of the specific (meth) acrylic copolymer. It is preferably 0.1 part by mass to 0.8 part by mass, more preferably 0.2 part by mass to 0.5 part by mass.
When the content of the silane coupling agent in the pressure-sensitive adhesive composition of the present disclosure is 0.1 part by mass or more with respect to 100 parts by mass of the specific (meth) acrylic copolymer, it is caused by partial thickness variation. There is a tendency to form an adhesive layer in which unevenness in the adhesive force is less likely to occur.
When the content of the silane coupling agent in the pressure-sensitive adhesive composition of the present disclosure is 1 part by mass or less with respect to 100 parts by mass of the specific (meth) acrylic copolymer, it is caused by the condensation reaction of the silane coupling agent. The decrease in the adhesive strength of the adhesive layer tends to be more suppressed.

〔Organic solvent〕
The pressure-sensitive adhesive composition of the present disclosure may contain an organic solvent.
When the pressure-sensitive adhesive composition of the present disclosure contains an organic solvent, the coatability may be improved.
Examples of the organic solvent include the same organic solvents as those used in the polymerization reaction of the above-mentioned specific (meth) acrylic copolymer.

When the pressure-sensitive adhesive composition of the present disclosure contains an organic solvent, it may contain only one type of organic solvent, or may contain two or more types of organic solvent.

When the pressure-sensitive adhesive composition of the present disclosure contains an organic solvent, the content of the organic solvent is not particularly limited and can be appropriately set depending on the intended purpose.

[Other ingredients]
The pressure-sensitive adhesive composition of the present disclosure may contain a component (so-called other component) other than the above-mentioned components, if necessary, as long as the effect is not impaired.
Other components include polymers other than specific (meth) acrylic copolymers, cross-linking catalysts, tackifiers, antioxidants, colorants (eg dyes and pigments), light stabilizers (eg UV absorbers). ), Various additives such as antistatic agents.

When the pressure-sensitive adhesive composition of the present disclosure contains other components, the content of the other components can be appropriately set as long as the effects of the pressure-sensitive adhesive composition of the present disclosure are not impaired.

<Use>
The use of the pressure-sensitive adhesive composition of the present disclosure is not particularly limited.
The pressure-sensitive adhesive composition of the present disclosure is suitable as, for example, a pressure-sensitive adhesive composition used for an optical member. Since the pressure-sensitive adhesive composition of the present disclosure is not easily deformed even when it is cut at a high temperature, it can be preferably applied, for example, when cutting using a polishing machine. Further, since the pressure-sensitive adhesive composition of the present disclosure can form a pressure-sensitive adhesive layer in which unevenness in the pressure-sensitive adhesive force due to partial thickness variation is unlikely to occur, for example, for an adherend having a special surface shape, the pressure-sensitive adhesive composition can be used. It is preferably applicable.
Specific examples of the use of the pressure-sensitive adhesive composition of the present disclosure include the use of bonding a finely printed adherend and an optical film, and the use of a polished adherend and a reinforcing film. Suitable for matching applications.

[Adhesive sheet]
The pressure-sensitive adhesive sheet of the present disclosure is a pressure-sensitive adhesive sheet including a pressure-sensitive adhesive layer formed by the pressure-sensitive adhesive composition of the present disclosure.
Since the pressure-sensitive adhesive sheet of the present disclosure includes the pressure-sensitive adhesive layer formed by the above-mentioned pressure-sensitive adhesive composition of the present disclosure, it is not easily deformed even when cut with high temperature, and the pressure-sensitive adhesive layer is partially formed. It shows a tendency that unevenness of adhesive force due to variation in thickness is unlikely to occur.
As the adherend of the pressure-sensitive adhesive sheet of the present disclosure, for example, an adherend that is cut at a high temperature and has a special surface shape is suitable. Examples of such an adherend include an adherend that has been finely printed and an adherend that has been subjected to a polishing treatment.

The pressure-sensitive adhesive sheet of the present disclosure may be a non-base material type pressure-sensitive adhesive sheet having no base material, or may be a base material type pressure-sensitive adhesive sheet having an adhesive layer on at least one side of the base material.
In the pressure-sensitive adhesive sheet of the present disclosure, the surface of the exposed pressure-sensitive adhesive layer may be protected by a release film.

The release film is not particularly limited as long as it can be easily peeled from the pressure-sensitive adhesive layer. For example, a resin film having one or both sides surface-treated with a release treatment agent (so-called easy peeling treatment). Can be mentioned.
Examples of the resin film include a polyester film typified by a polyethylene terephthalate (PET) film. Examples of the peeling treatment agent include a silicone-based peeling treatment agent (for example, silicone), a wax-based peeling treatment agent (for example, paraffin wax), and a fluorine-based peeling treatment agent (for example, a fluorine-based resin).
The release film protects the surface of the pressure-sensitive adhesive layer until the pressure-sensitive adhesive sheet is put into practical use, and is peeled off during use.

The thickness of the pressure-sensitive adhesive layer is not particularly limited, and can be appropriately set according to the shape of the adherend, the surface roughness, and the like.
The thickness of the pressure-sensitive adhesive layer is generally 1 μm to 100 μm, preferably 5 μm to 50 μm, and more preferably 10 μm to 30 μm.

The "thickness of the pressure-sensitive adhesive layer" in the present disclosure means the average thickness of the pressure-sensitive adhesive layer.
The average thickness of the pressure-sensitive adhesive layer is a value measured by the following method.
In the thickness direction of the pressure-sensitive adhesive layer, an arithmetic average value of the thickness of the pressure-sensitive adhesive layer measured at 10 randomly selected points is obtained, and the obtained value is taken as the average thickness of the pressure-sensitive adhesive layer. The thickness of the pressure-sensitive adhesive layer is measured using a film thickness meter.

When the pressure-sensitive adhesive sheet of the present disclosure includes a base material, the base material is not particularly limited.
Examples of the base material include a polyolefin resin (for example, polyethylene and polypropylene), a polyester resin [for example, polyethylene terephthalate (PET)], an acetate resin (for example, a triacetyl cellulose resin), and a polyether sulfone resin. Examples thereof include a film containing a resin such as a polycarbonate resin, a polyamide resin, a polyimide resin, an acrylic resin, a vinyl chloride resin, an ABS (Acrylonitrile Butadiene Styrene) resin, and a fluororesin.

Surface treatments such as corona discharge treatment and plasma discharge treatment (so-called easy-adhesion treatment) are applied to the surface of the base material on the side where the pressure-sensitive adhesive layer is provided, from the viewpoint of improving the adhesion between the base material and the pressure-sensitive adhesive layer. It may be applied.

The substrate may contain various additives such as plasticizers, colorants (eg, dyes and pigments), heat stabilizers, light stabilizers, antistatic agents, flame retardants, antioxidants and the like.
The base material may be partially or wholly patterned.

The thickness of the base material is not particularly limited.
The thickness of the base material is generally 10 μm to 500 μm, preferably 10 μm to 300 μm, and more preferably 10 μm to 200 μm.

The "base material thickness" in the present disclosure means the average thickness of the base material.
The average thickness of the base material is a value measured by a method based on the above-mentioned method for measuring the average thickness of the pressure-sensitive adhesive layer.

[How to make an adhesive sheet]
The pressure-sensitive adhesive sheet of the present disclosure can be produced by a known method.
Examples of the method for producing the pressure-sensitive adhesive sheet of the present disclosure include the following methods.
In the case of a non-base material type pressure-sensitive adhesive sheet, first, the pressure-sensitive adhesive composition of the present disclosure is applied to the easily peel-treated surface of the release film to form a coating film on the release film. Next, the formed coating film is dried to form an adhesive film on the release film. Next, the exposed surface of the formed adhesive film is laminated on the easily peelable surface of the separately prepared release film and then cured to form a laminated structure of the release film / adhesive layer / release film. It is possible to produce a non-base material type adhesive sheet having.

In the case of a base material type pressure-sensitive adhesive sheet, first, the pressure-sensitive adhesive composition of the present disclosure is applied to the easy-adhesion-treated surface of the base material to form a coating film on the base material. Next, the formed coating film is dried to form an adhesive film on the substrate. Next, the exposed surface of the formed adhesive film is laminated on the easily peelable surface of the release film and then cured to have a laminated structure of a release film / adhesive layer / base material. A material type adhesive sheet can be produced.

As another method, for example, the following method may be mentioned.
By applying the pressure-sensitive adhesive composition of the present disclosure to the easily peelable surface of the release film, a coating film is formed on the release film. Next, the formed coating film is dried to form an adhesive film on the release film. Next, the exposed surface of the formed adhesive film is laminated on the easy-adhesion-treated surface of the base material and then cured to have a laminated structure of the base material / adhesive layer / release film. A material type adhesive sheet can be produced.

The method of applying the pressure-sensitive adhesive composition is not particularly limited.
Examples of the method for applying the pressure-sensitive adhesive composition include known methods using a gravure roll coater, a reverse roll coater, a kiss roll coater, a dip roll coater, a knife coater, a spray coater, a bar coater, an applicator and the like.
The amount of the pressure-sensitive adhesive composition applied is not particularly limited, and is appropriately set according to, for example, the thickness of the pressure-sensitive adhesive layer to be formed.

The method for drying the coating film is not particularly limited.
Examples of the method for drying the coating film include methods such as natural drying, heat drying, hot air drying, and vacuum drying.
The drying temperature and drying time of the coating film are not particularly limited, and are appropriately set according to the thickness of the coating film, the amount of the organic solvent in the coating film, and the like.
As an example of the drying condition, there is a condition of drying at 70 ° C. to 120 ° C. for 30 seconds to 180 seconds using a hot air dryer.

Curing is performed, for example, in an environment with an atmospheric temperature of 20 ° C. to 35 ° C. and a relative humidity of 45% to 55% (that is, 45% RH to 55% RH) for 4 to 7 days.

[Optical member]
The optical member of the present disclosure is an optical member including a pressure-sensitive adhesive layer formed by the pressure-sensitive adhesive composition of the present disclosure.
Since the optical member of the present disclosure includes the pressure-sensitive adhesive layer formed by the above-mentioned pressure-sensitive adhesive composition of the present disclosure, it is not easily deformed even when cut with high temperature, and the pressure-sensitive adhesive layer is partially formed. It shows a tendency that unevenness of adhesive force due to variation in thickness is unlikely to occur.
The optical member is not particularly limited, and examples thereof include a member constituting a device (so-called optical device) such as an image display device and an input device, or a member used for these devices.
Specific examples of the optical member include a polarizing plate, an AG (Anti-Glare) polarizing plate, a wavelength plate, a retardation plate including a wavelength plate such as 1/2 and 1/4, a viewing angle compensation film, an optical compensation film, and an improvement in brightness. Examples thereof include a film, a light guide plate, a reflective film, an antireflection film, a transparent conductive film such as an ITO (Indium-Tin Oxide) film, a prism sheet, a lens sheet, and a diffusion plate.
As the material of the optical member, a polyolefin resin (for example, polyethylene resin and polyester resin), an acetate resin (for example, triacetyl cellulose resin), a polyether sulfone resin, a polycarbonate resin, and a polyamide resin, Examples thereof include resins such as polyimide resins, acrylic resins, vinyl chloride resins, ABS (Acrylonitrile Butadiene Styrene) resins, and fluororesins.

Hereinafter, the pressure-sensitive adhesive composition and the pressure-sensitive adhesive sheet of the present disclosure will be described in more detail with reference to Examples. The present disclosure is not limited to the following examples as long as the gist is not exceeded.

[Manufacturing of (meth) acrylic copolymer]
[Manufacturing Example A-1]
70 parts by mass of ethyl acetate [organic solvent] was charged in the reaction vessel of the reaction device equipped with a stirrer, a reflux condenser, a sequential dropping device, and a thermometer. Then, in another container, it has 99.9 parts by mass of n-butyl acrylate [n-BA; acrylic acid alkyl ester monomer] and 2-hydroxyethyl acrylate [2HEA; crosslinkable functional group (type: hydroxyl group). Monomer] 100.0 parts by mass of a monomer mixture consisting of 0.1 parts by mass was prepared. The prepared monomer mixture was placed in the reaction vessel and then heated to 70 ° C. Then, under the above temperature conditions, 50.0 parts by mass of ethyl acetate and 0.026 parts by mass of 2,2'-azobisisobutyronitrile [AIBN; polymerization initiator] were added to the reaction vessel over 120 minutes. After the dropping was completed, the reaction was carried out for another 150 minutes to complete the reaction. The solution after completion of the reaction was diluted with ethyl acetate so that the solid content concentration became 15.0% by mass to obtain a solution of the (meth) acrylic copolymer A-1.

The "solid content concentration" as used herein means the mass ratio of the (meth) acrylic copolymer A-1 to the solution of the (meth) acrylic copolymer A-1.
The same applies to each of the following (meth) acrylic copolymers A-2 to A-7 solutions.

[Manufacturing Examples A-2 to A-7]
In Production Examples A-2 to A-7, the monomer composition of the (meth) acrylic copolymer was changed to the monomer composition shown in Table 1, and the amount of the organic solvent used and the polymerization initiator were changed. The same operation as in Production Example A-1 was performed except that the weight average molecular weight of the (meth) acrylic copolymer was adjusted to the weight average molecular weight shown in Table 1 by adjusting at least one of the amounts used. Solutions of (meth) acrylic copolymers A-2 to A-7 having a solid content concentration of 15.0% by mass were obtained.

Monomer composition (unit: mass%) of (meth) acrylic copolymers A-1 to A-7, glass transition temperature (Tg, unit: ° C.), and weight average molecular weight [Mw, unit: 10,000 (table). Among them, "× 10 ⁴ notation)] is shown in Table 1.

The glass transition temperature of the (meth) acrylic copolymers A-1 to A-7 was calculated by the same method as the above-mentioned method for calculating the glass transition temperature of the specific (meth) acrylic copolymer.
The weight average molecular weights of the (meth) acrylic copolymers A-1 to A-7 were measured by the same method as the above-mentioned method for measuring the weight average molecular weight of the specific (meth) acrylic copolymer.

Among the (meth) acrylic copolymers A-1 to A-7 obtained above, the (meth) acrylic copolymers A-1 to A-3, A-6, and A-7 are Corresponds to the specific (meth) acrylic copolymer in the present disclosure.

In Table 1, the numerical values described in the column of "monomer composition [mass%]" are all solid content conversion values.

Details of each monomer shown in Table 1 are as shown below.
<(Meta) Acrylic Acid Alkyl Ester Monomer>
"N-BA"; n-butyl acrylate "2EHA"; 2-ethylhexyl acrylate <monomer having a crosslinkable functional group>
"2HEA"; 2-hydroxyethyl acrylate (crosslinkable functional group: hydroxyl group)
"AA"; acrylic acid (crosslinkable functional group: carboxy group)

In Table 1, "-" described in the column of monomer composition means that the monomer corresponding to the column is not contained.
In Table 1, "glass transition temperature" is expressed as "Tg" and "weight average molecular weight" is expressed as "Mw".

[Preparation of adhesive composition]
[Example 1]
667 parts by mass (100 parts by mass as solid content) of the solution of the (meth) acrylic copolymer A-2 and Coronate (registered trademark) L-45E [trade name, tolylene diisocyanate] which is an isocyanate-based cross-linking agent as a cross-linking agent. Adduct body of (TDI) and trimetylol propane (TMP), solid content concentration: 45% by mass, manufactured by Toso Co., Ltd.] 22.2 parts by mass (10.0 parts by mass as solid content) and silane coupling agent KBM-403 [trade name, manufactured by Shin-Etsu Chemical Industry Co., Ltd.] 0.2 parts by mass and SELM (registered trademark) Superpolymer SH3400P [trade name, specified polyrotaxan, manufactured by ASM Co., Ltd.] 20.0 parts by mass. , Was thoroughly mixed to obtain the pressure-sensitive adhesive composition of Example 1.

[Examples 2 to 15]
In Example 1, the same operations as in Example 1 were carried out except that the composition of the pressure-sensitive adhesive composition was changed to the composition shown in Table 2, to obtain each pressure-sensitive adhesive composition of Examples 2 to 15.

[Comparative Examples 1 to 10]
In Example 1, the same operations as in Example 1 were carried out except that the composition of the pressure-sensitive adhesive composition was changed to the composition shown in Table 3, to obtain each pressure-sensitive adhesive composition of Comparative Examples 1 to 10.

[evaluation]
The following evaluations were performed using the pressure-sensitive adhesive compositions of Examples 1 to 15 and Comparative Examples 1 to 10.
The results are shown in Tables 2 and 3.

<Preparation of adhesive sheet X for evaluation>
The pressure-sensitive adhesive composition prepared above was surface-treated with a silicone-based release treatment agent, and the release film P [trade name: Film Vina (registered trademark) 100E-0010 No. 23, Thickness: 100 μm, manufactured by Fujimori Kogyo Co., Ltd.] was applied to the surface-treated surface so that the thickness after drying was 100 μm to form a coating film. Next, the formed coating film was dried using a hot air circulation type dryer under drying conditions of a drying temperature of 100 ° C. and a drying time of 1 minute to form an adhesive film on the release film P. Next, the exposed surface of the adhesive film was surface-treated with a separately prepared silicone-based release treatment agent, and the release film Q [trade name: Film Vina (registered trademark) 25E-0010 BD, thickness: 25 μm, Fujimori Kogyo Co., Ltd. ) Was laminated on the surface-treated surface, and then allowed to stand in an environment with an ambient temperature of 23 ° C. and 50% RH for 4 days for curing to prepare an evaluation pressure-sensitive adhesive sheet X. The prepared pressure-sensitive adhesive sheet X for evaluation has a laminated structure of a release film Q / a pressure-sensitive adhesive layer (thickness: 100 μm) / a release film P.

<Preparation of adhesive sheet Y for evaluation>
A release film in which the pressure-sensitive adhesive composition prepared above is surface-treated with a silicone-based release treatment agent [trade name: Film Vina (registered trademark) 100E-0010 No. 23, manufactured by Fujimori Kogyo Co., Ltd.] was applied to the surface-treated surface so that the film thickness after drying was 20 μm to form a coating film. Next, the formed coating film was dried using a hot air circulation type dryer under drying conditions of a drying temperature of 100 ° C. and a drying time of 1 minute to form an adhesive film on the release film. Next, the exposed surface of the adhesive film was easily adhered to a polyethylene terephthalate (PET) film [trade name: Toyobo ester (registered trademark) film, model number: G2P2, thickness: 50 μm, manufactured by Toyobo Film Solution Co., Ltd.]. After being laminated on the easy-adhesion-treated surface of No. 1 and pressure-bonded by passing it through a pressurized nip roll, it was left to stand in an environment with an atmospheric temperature of 23 ° C. and 50% RH for 4 days to be cured, and then the adhesive sheet Y for evaluation was applied. Was produced. The produced evaluation pressure-sensitive adhesive sheet Y has a laminated structure of a release film / pressure-sensitive adhesive layer (thickness: 20 μm) / PET film (base material).

<Preparation of adhesive sheet Z for evaluation>
In the preparation of the pressure-sensitive adhesive sheet Y for evaluation, the pressure-sensitive adhesive composition prepared above was surface-treated with a silicone-based release treatment agent to form a release film [trade name: Film Vina (registered trademark) 100E-0010 No. 23, manufactured by Fujimori Kogyo Co., Ltd.] The same operation as the production of the adhesive sheet Y for evaluation was performed except that the surface-treated surface was coated so that the thickness after drying was 10 μm to form a coating film. This was performed to prepare a pressure-sensitive adhesive sheet Z for evaluation. The produced pressure-sensitive adhesive sheet Z for evaluation has a laminated structure of a release film / pressure-sensitive adhesive layer (thickness: 10 μm) / PET film (base material).

1. 1. Deformation when cutting with high temperature Whether or not the pressure-sensitive adhesive layer is not easily deformed even when cutting with high temperature was evaluated using the elastic modulus of the pressure-sensitive adhesive layer at 85 ° C. as an index. Specifically, the following evaluations were made.
Four evaluation adhesive sheet pieces prepared by cutting the evaluation adhesive sheet X produced above into a size of 25 mm × 150 mm were prepared. Next, the release film P and the release film Q were peeled off from the prepared four evaluation pressure-sensitive adhesive sheet pieces [Structure: release film Q / pressure-sensitive adhesive layer (thickness: 100 μm) / release film P], and the surface of the pressure-sensitive adhesive layer was peeled off. They were bonded together to form a pressure-sensitive adhesive layer having a thickness of 400 μm. The formed adhesive layer was cut out according to the measuring jig PP8 [manufactured by Antonio Par] to prepare a test piece. The elastic modulus (unit: Pa) of the prepared test piece in an environment of an atmospheric temperature of 85 ° C. and 50% RH was measured using a dynamic viscoelasticity measuring device [model number: MCR301] manufactured by Antonio Par Co., Ltd. as a measuring device. did. Then, the evaluation was performed according to the following evaluation criteria.
If the evaluation result is "A", "B", or "C", it is determined that the adhesive layer is not easily deformed even when cut with high temperature.

-Evaluation criteria-
A: The elastic modulus was 1.0 × ¹⁰⁵ Pa or more.
B: The elastic modulus was in the range of 5.0 × 10 ⁴ Pa or more and less than 1.0 × 10 ⁵ Pa.
C: The elastic modulus was in the range of 1.0 × 10 ⁴ Pa or more and less than 5.0 × 10 ⁴ Pa.
D: The elastic modulus was less than 1.0 × 10 ⁴ Pa.

2. 2. Unevenness in adhesive strength due to partial variation in thickness Whether or not the adhesive layer is less likely to cause unevenness in adhesive strength due to partial variation in thickness depends on the adhesion between two adhesive layers with different thicknesses. The difference in force was used as an index for evaluation. Specifically, the following evaluations were made.
The evaluation adhesive sheet Y produced above was cut into a size of 25 mm × 75 mm to prepare an evaluation adhesive sheet piece Y. Next, the release film of the prepared pressure-sensitive adhesive sheet piece Y for evaluation [Structure: release film / pressure-sensitive adhesive layer (thickness: 20 μm) / PET film (base material)] was peeled off, and the surface of the pressure-sensitive adhesive layer exposed by the peeling was peeled off. , Non-alkali glass [trade name: Eagle XG, Corning Inc.] (hereinafter, simply referred to as "glass") is laminated and bonded, and then a 2 kg roller is reciprocated once to crimp the laminated body Y. Made. The produced laminated body Y has a laminated structure of a glass plate (adhesive body) / evaluation pressure-sensitive adhesive sheet piece Y [structure: pressure-sensitive adhesive layer (thickness: 20 μm) / PET film (base material)]. Next, the prepared laminate Y was allowed to stand in an environment with an atmospheric temperature of 23 ° C. and 50% RH for 24 hours to obtain a test piece Y.
Next, the evaluation adhesive sheet Z produced above was cut into a size of 25 mm × 75 mm to prepare an evaluation adhesive sheet piece Z. Next, the release film of the prepared pressure-sensitive adhesive sheet piece Z for evaluation [Structure: release film / pressure-sensitive adhesive layer (thickness: 10 μm) / PET film (base material)] was peeled off, and the surface of the pressure-sensitive adhesive layer exposed by the peeling was peeled off. , Non-alkali glass [trade name: Eagle XG, Corning Inc.] (hereinafter, simply referred to as "glass") is laminated and bonded, and then a 2 kg roller is reciprocated once to crimp the laminated body Z. Made. The produced laminated body Z has a laminated structure of a glass plate (adhesive body) / evaluation pressure-sensitive adhesive sheet piece Z [structure: pressure-sensitive adhesive layer (thickness: 10 μm) / PET film (base material)]. Next, the prepared laminate Z was allowed to stand for 24 hours in an environment with an atmospheric temperature of 23 ° C. and 50% RH to obtain a test piece Z.
Next, for each of the test piece Y and the test piece Z, the adhesive force (unit: N / 25 mm) when the adhesive sheet piece is peeled 180 ° from the glass in the long side (75 mm) direction is measured by A Co., Ltd. -Measurement was performed using a single column type material tester [model number: STA-1225] manufactured by And Day under the conditions of an ambient temperature of 23 ° C. and a peeling speed of 300 mm / min under an environment of an atmospheric temperature of 23 ° C. and a peeling speed of 300 mm / min. The difference between the force and the adhesive force of the test piece Z was determined. Then, the evaluation was performed according to the following evaluation criteria.
If the evaluation result is "A", "B", or "C", it is determined that the pressure-sensitive adhesive layer is unlikely to cause unevenness in adhesive strength due to partial variation in thickness.

-Evaluation criteria-
A: The difference in adhesive strength was less than 3.0 N / 25 mm.
B: The difference in adhesive strength was in the range of 3.0 N / 25 mm or more and less than 4.0 N / 25 mm.
C: The difference in adhesive strength was in the range of 4.0 N / 25 mm or more and less than 5.0 N / 25 mm.
D: The difference in adhesive strength was 5.0 N / 25 mm or more.

In Tables 2 and 3, "-" means that the corresponding component is not blended in the column.
In Tables 2 and 3, the numerical values described in the column of "parts by mass" are all solid content conversion values.

Details of the cross-linking agent, silane coupling agent, and polyrotaxane shown in Table 2 and / or Table 3 are as shown below.
<Crosslinking agent>
-Isocyanate cross-linking agent-
"Coronate L-45E" [Product name, adduct of toluene diisocyanate (TDI) and trimethylolpropane (TMP), solid content concentration: 45% by mass, manufactured by Tosoh Corporation]
"Takenate D-110N" [Product name, adduct of xylylene diisocyanate (XDI) and trimethylolpropane (TMP), solid content concentration: 75% by mass, manufactured by Mitsui Chemicals, Inc.]
"Sumijuru N75" [trade name, hexamethylene diisocyanate (HMDI) biuret, solid content concentration: 75% by mass, manufactured by Sumika Covestro Urethane Co., Ltd.]
The above-mentioned "Coronate", "Takenate", and "Sumijour" are all registered trademarks.

<Silane coupling agent>
"KBM-403" [Product name, epoxy group-containing silane compound, solid content concentration: 100% by mass, manufactured by Shin-Etsu Chemical Co., Ltd.]
"KBM-903" [Product name, amino group-containing silane compound, solid content concentration: 100% by mass, manufactured by Shin-Etsu Chemical Co., Ltd.]
"X-41-1810" [Product name, thiol group-containing silane compound, solid content concentration: 100% by mass, manufactured by Shin-Etsu Chemical Co., Ltd.]

<Polyrotaxane>
-Specific polyrotaxane-
"SH3400P" [Product name: CELM Super Polymer SH3400P, hydroxyl value: 72 mgKOH / g, weight average molecular weight: 700,000, manufactured by ASM Co., Ltd.]
-Other polyrotaxanes-
"SA1305P-20" [Product name: SELM Superpolymer SA1305P-20, polyrotaxane having two or more (meth) acryloyl groups with cyclic molecules, acrylic equivalent: 7000 g / eq, weight average molecular weight: 200,000, 50% by mass acetate Ethyl solution, manufactured by ASM Co., Ltd.]
The above "CELM" is a registered trademark.

As shown in Table 2, the pressure-sensitive adhesive layer formed by the pressure-sensitive adhesive compositions of Examples 1 to 15 is not easily deformed even when cut with high temperature, and is caused by partial thickness variation. It was confirmed that unevenness in adhesive strength is unlikely to occur.
On the other hand, as shown in Table 3, the pressure-sensitive adhesive layer formed by the pressure-sensitive adhesive compositions of Comparative Examples 1 to 10 is caused by deformation when cutting with high temperature and partial thickness variation. In at least one evaluation of the unevenness of the adhesive strength, it was confirmed that it was inferior to the adhesive layer formed by the adhesive composition of the example.
In Comparative Example 10 containing another polyrotaxane, it is presumed that the reaction between the silane coupling agent and the polyrotaxane did not occur.

Claims (4)

It contains a structural unit (A) derived from a monomer having a crosslinkable functional group and a structural unit (B) derived from a (meth) acrylic acid alkyl ester monomer, and the content of the structural unit (A). Is 0.01% by mass or more and 5% by mass or less with respect to all the constituent units (meth) acrylic copolymer and
Polyrotaxane in which the cyclic molecule has a side chain containing two or more carbon atoms and the end of the side chain is a hydroxyl group,
With a cross-linking agent,
Silane coupling agent and
Including
The content of the polyrotaxane is 20 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the (meth) acrylic copolymer.
A pressure-sensitive adhesive composition in which the content of the cross-linking agent is 5 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the (meth) acrylic copolymer. The pressure-sensitive adhesive composition according to claim 1, wherein the (meth) acrylic copolymer has a glass transition temperature of less than 0 ° C. A pressure-sensitive adhesive sheet comprising the pressure-sensitive adhesive layer formed by the pressure-sensitive adhesive composition according to claim 1 or 2. An optical member including a pressure-sensitive adhesive layer formed by the pressure-sensitive adhesive composition according to claim 1 or 2.