WO2016167133A1

WO2016167133A1 - Adhesive sheet and method for manufacturing joined body

Info

Publication number: WO2016167133A1
Application number: PCT/JP2016/060645
Authority: WO
Inventors: 鈴木俊英
Original assignee: 日東電工株式会社
Priority date: 2015-04-13
Filing date: 2016-03-31
Publication date: 2016-10-20
Also published as: JP2016199701A

Abstract

This adhesive sheet (X1) has an adhesive-agent layer (1) curable by radiation exposure and including an acrylic copolymer, a basic monomer, and a photopolymerization initiator. The acrylic copolymer in the adhesive-agent layer (1) includes as a monomer unit a carboxyl-group-containing monomer in which the content of a starting material monomer component for forming the acrylic copolymer is 0.5-10% by mass. In this method for manufacturing a joined body, a second member is temporarily fixed to a first member via the adhesive sheet (X1), after which the adhesive sheet (X1) or the adhesive-agent layer (1) thereof is irradiated by radiation and the adhesive-agent layer (1) is cured.

Description

Adhesive sheet and method for producing joined body

The present invention relates to a pressure-sensitive adhesive sheet and a method for producing a joined body using the pressure-sensitive adhesive sheet.

In recent years, pressure-sensitive adhesive sheets (pressure-sensitive adhesive sheets) having a pressure-sensitive adhesive layer forming an adhesive surface have been used in various technical fields. The single-sided pressure-sensitive adhesive sheet having a pressure-sensitive adhesive surface on one side of the pressure-sensitive adhesive sheet is bonded to the member surface, for example, and used to protect the member. The double-sided pressure-sensitive adhesive sheet having pressure-sensitive adhesive surfaces on both sides of the pressure-sensitive adhesive sheet is used, for example, for joining between members. The adhesive sheet is required to have a certain adhesive force (adhesive strength) to the adherend depending on the application.

Since the pressure-sensitive adhesive layer of such a pressure-sensitive adhesive sheet is generally made of a viscoelastic body, it has a property of relaxing the external force when an external force is applied to the pressure-sensitive adhesive layer. Utilizing such properties, pressure-sensitive adhesive sheets have been developed that exhibit characteristics of absorbing impact force acting from the outside while being bonded to an adherend (for example, Patent Document 1 and Patent Document 2).

JP 2011-95318 A JP 2011-145683 A

However, in the pressure-sensitive adhesive sheet, when an external force is applied, it may be required to transmit the external force efficiently. For example, an adhesive sheet for protecting the surface of a touch panel may be required to efficiently transmit force to the panel from the viewpoint of response sensitivity to a touch operation on the panel. Further, the pressure-sensitive adhesive sheet for joining members may be required to efficiently transmit the force acting on one member to the other member via the pressure-sensitive adhesive sheet.

The present invention has been conceived under such circumstances, and an object of the present invention is to provide a pressure-sensitive adhesive sheet suitable for realizing a high elastic modulus with a good adhesive force in a pressure-sensitive adhesive layer. Moreover, this invention makes it the other objective to provide the conjugate | zygote manufacturing method performed using such an adhesive sheet.

According to the first aspect of the present invention, an adhesive sheet is provided. This pressure-sensitive adhesive sheet has an acrylic pressure-sensitive adhesive layer. This acrylic pressure-sensitive adhesive layer contains an acrylic copolymer, a basic monomer, and a photopolymerization initiator, and can be cured by irradiation with radiation. The acrylic copolymer in the acrylic pressure-sensitive adhesive layer includes a monomer unit derived from a carboxyl group-containing monomer whose content in the raw material monomer component for forming the acrylic copolymer is 0.5 to 10% by mass. . In the present invention, the basic monomer is a monomer having an aqueous monomer solution having a pH of 8.0 or more and can cause a polymerization reaction initiated by a photopolymerization initiator that has been irradiated with radiation. Moreover, the adhesive sheet includes an adhesive tape in the form of a tape.

In the present pressure-sensitive adhesive sheet, since the acrylic pressure-sensitive adhesive layer contains an acrylic copolymer as a main agent, basic characteristics such as adhesiveness of the acrylic pressure-sensitive adhesive can be reflected in the pressure-sensitive adhesive layer. Moreover, since such an adhesive layer contains a polymerizable monomer and a photopolymerization initiator and can be cured by radiation irradiation, the adhesive layer can be made highly elastic by the curing. For example, after the adhesive sheet is bonded to an adherend, or after the adhesive sheet is interposed between the members and the members are temporarily fixed, the adhesive layer of the adhesive sheet is made highly elastic by irradiation. Can be made.

In the acrylic pressure-sensitive adhesive layer of the present pressure-sensitive adhesive sheet, a basic monomer exists as a polymerizable monomer, and a carboxyl group-containing monomer capable of acid-base interaction with the monomer is a main component of the acrylic copolymer. Included as a monomer unit. Therefore, the polymer formed by polymerizing the basic monomer in the pressure-sensitive adhesive layer through radiation irradiation contributes to the increase in elasticity of the pressure-sensitive adhesive layer, and at a plurality of locations between the acrylic copolymer. The acid-base interaction also contributes to the adhesiveness of the adhesive layer after curing. That is, in the pressure-sensitive adhesive layer after curing of the pressure-sensitive adhesive sheet, it is easy to efficiently obtain both adhesiveness and high elasticity.

In addition, the acrylic copolymer in the acrylic pressure-sensitive adhesive layer of the present pressure-sensitive adhesive sheet contains a carboxyl group-containing monomer having a content of 0.5 to 10% by mass in the raw material monomer component for forming the copolymer. As a monomer unit. Since the acrylic copolymer in the pressure-sensitive adhesive layer contains a carboxyl group-containing monomer unit within such a ratio, the pressure-sensitive adhesive layer remains in the acrylic monomer unit as the main element of the acrylic copolymer even after curing. It is easy to reflect basic characteristics such as adhesiveness mainly caused by it appropriately.

As described above, this pressure-sensitive adhesive sheet is suitable for realizing a high elastic modulus with good adhesive force in the pressure-sensitive adhesive layer. The present pressure-sensitive adhesive sheet suitable for realizing a high elastic modulus with good adhesive force in the pressure-sensitive adhesive layer is suitable for transmitting the external force to the adherend when an external force is applied.

Preferably, the acrylic copolymer includes a monomer unit derived from a hydroxyl group-containing monomer. More preferably, the acrylic copolymer includes a monomer unit derived from a hydroxyl group-containing monomer having a content of 0.01 to 5% by mass in the raw material monomer component for forming the acrylic copolymer. According to such a configuration, it is easy to obtain adhesiveness and appropriate cohesive force in the acrylic pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet. Moreover, according to such a structure, when the acrylic adhesive layer of this adhesive sheet contains crosslinking agents, such as an isocyanate type crosslinking agent, hardness and favorable adhesive reliability are easily obtained in the said adhesive layer.

Preferably, the acrylic copolymer includes a monomer unit derived from a nitrogen atom-containing monomer. According to such a configuration, hardness, adhesion, and sufficient transparency are easily obtained in the acrylic pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet. More preferably, the acrylic copolymer includes a monomer unit derived from a nitrogen atom-containing monomer having a content of 0.5 to 30% by mass in the raw material monomer component for forming the acrylic copolymer. Such a configuration is suitable for ensuring hardness, adhesiveness, and sufficient transparency in the acrylic pressure-sensitive adhesive layer of the present pressure-sensitive adhesive sheet and realizing good adhesion reliability.

The nitrogen atom-containing monomer preferably contains an N-vinyl cyclic amide and / or (meth) acrylamide represented by the following formula (1). Such a configuration is suitable for achieving hardness, adhesion, and sufficient transparency in the acrylic pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet.

[In Formula (1), R ¹ represents a divalent organic group]

The nitrogen atom-containing monomer is preferably a group consisting of N-vinyl-2-pyrrolidone, N-vinyl-2-caprolactam, N, N-dimethyl (meth) acrylamide, and N, N-diethyl (meth) acrylamide. Including at least one selected from more. Such a configuration is suitable for achieving hardness, adhesion, and sufficient transparency in the acrylic pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet.

Preferably, the basic monomer has an amide group and / or an amino group in the molecule and an acid dissociation constant pKa of 8.0 or more. Such a structure is used to cause an acid-base interaction between the carboxyl group-containing monomer unit in the acrylic copolymer and the basic monomer or basic monomer unit in the acrylic pressure-sensitive adhesive layer. Is preferred.

Preferably, in the acrylic pressure-sensitive adhesive layer, the content of the basic monomer is 0.1 to 20 parts by mass with respect to 100 parts by mass of the acrylic copolymer, and the content of the photopolymerization initiator is 100% by mass. The amount is 0.05 to 5 parts by mass with respect to parts by mass. Such a configuration is suitable for realizing a high elastic modulus with a good adhesive force in the pressure-sensitive adhesive layer after curing of the pressure-sensitive adhesive sheet.

Preferably, the mass ratio of the basic monomer in the acrylic pressure-sensitive adhesive layer to the carboxyl group-containing monomer contained in the raw material monomer component for forming the acrylic copolymer in the acrylic pressure-sensitive adhesive layer is 0.01 to 40. Such a configuration is suitable for realizing a high elastic modulus with a good adhesive force in the pressure-sensitive adhesive layer after curing of the pressure-sensitive adhesive sheet.

Preferably, the basic monomer includes at least one selected from a compound group represented by the following formula (2) and a compound group represented by the following formula (3). Such a configuration is suitable for realizing a high elastic modulus with a good adhesive force in the pressure-sensitive adhesive layer after curing of the pressure-sensitive adhesive sheet.

[In the formula (2), R ² represents a hydrogen atom or a methyl group, R ³ represents a linear or branched alkylene group having 2 to 6 carbon atoms, and R ⁴ and R ⁵ are each hydrogen. Represents an atom or a linear or branched alkyl group having 1 to 4 carbon atoms]

[In the formula (3), R ⁶ represents a hydrogen atom or a methyl group, R ⁷ represents a linear or branched alkylene group having 2 to 6 carbon atoms, and R ⁸ and R ⁹ are each hydrogen. Represents an atom or a linear or branched alkyl group having 1 to 4 carbon atoms]

Preferably, the basic monomer includes at least one selected from the group consisting of N- (3-dimethylaminopropyl) methacrylamide, N- (3-dimethylaminopropyl) acrylamide, and 2-dimethylaminoethyl methacrylate. Such a configuration is suitable for realizing a high elastic modulus with a good adhesive force in the pressure-sensitive adhesive layer after curing of the pressure-sensitive adhesive sheet.

Preferably, the basic monomer has a boiling point of 120 ° C. or higher. In the present specification, the boiling point is a temperature measured at normal pressure unless there is a specific pressure condition. Such a configuration is suitable for suppressing the evaporation of the basic monomer from the acrylic pressure-sensitive adhesive layer in the production process of the pressure-sensitive adhesive sheet.

Preferably, the acrylic pressure-sensitive adhesive layer further contains a polyfunctional acrylic oligomer. The polyfunctional acrylic oligomer preferably has three or more (meth) acryloyl groups in the molecule. The polyfunctional acrylic oligomer preferably has a weight average molecular weight of 500 to 30,000. These structures are suitable for realizing a high elastic modulus with a good adhesive force in the post-curing pressure-sensitive adhesive layer.

Preferably, the acrylic copolymer has a weight average molecular weight of 400,000 to 2 million. Such a configuration is mainly suitable for realizing a good adhesive force in both states before and after the curing of the acrylic pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet.

According to the second aspect of the present invention, a method for manufacturing a joined body is provided. In this method, after temporarily fixing the second member to the first member via the pressure-sensitive adhesive sheet according to the first aspect of the present invention, the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet is irradiated with radiation. The adhesive layer is cured. This method is suitable for manufacturing a joined body in which a high elastic modulus is realized with a good adhesive force in a pressure-sensitive adhesive layer interposed between members to form a joined body.

It is sectional drawing of the adhesive sheet which concerns on one Embodiment of this invention. It is sectional drawing of the adhesive sheet which concerns on other embodiment of this invention. It is sectional drawing of the adhesive sheet which concerns on other embodiment of this invention. 3 shows a joined body manufacturing method according to another embodiment of the present invention.

FIG. 1 is a cross-sectional view of an adhesive sheet X1 according to an embodiment of the present invention. The pressure-sensitive adhesive sheet X1 is composed of a pressure-sensitive adhesive layer 1, and the upper surface and the lower surface in the figure of the pressure-sensitive adhesive layer 1 form the pressure-sensitive adhesive surface of the pressure-sensitive adhesive sheet X1. That is, the pressure-sensitive adhesive sheet X1 of the present embodiment is a double-sided pressure-sensitive adhesive sheet having a pressure-sensitive adhesive surface on both sides, and is a substrate-less pressure-sensitive adhesive sheet having no base material. Further, the thickness of the pressure-sensitive adhesive sheet X1 is set according to the application, and is, for example, 5 to 150 μm.

The pressure-sensitive adhesive layer 1 of the pressure-sensitive adhesive sheet X1 is an acrylic pressure-sensitive adhesive layer containing an acrylic copolymer, a polymerizable basic monomer, and a photopolymerization initiator, and can be cured by radiation irradiation.

[Acrylic copolymer]
The acrylic copolymer contained in the pressure-sensitive adhesive layer 1 of the pressure-sensitive adhesive sheet X1 is the main agent of the pressure-sensitive adhesive layer 1 as an acrylic pressure-sensitive adhesive layer, and includes an acrylic monomer unit derived from an acrylic monomer as a main monomer unit. The main agent is a component occupying the largest mass ratio among the constituent components. The acrylic monomer is a monomer having at least one acryloyl group or methacryloyl group in the molecule. The acrylic copolymer includes a carboxyl group-containing monomer unit derived from a carboxyl group-containing monomer. The carboxyl group-containing monomer is a monomer having at least one carboxyl group in the molecule. The carboxyl group-containing monomer may belong to an acrylic monomer or may not belong to an acrylic monomer. Such an acrylic copolymer mainly has a function of expressing the basic characteristics of the acrylic pressure-sensitive adhesive in the pressure-sensitive adhesive layer 1.

Suitable examples of the acrylic monomer for the acrylic monomer unit of the acrylic copolymer include (meth) acrylic acid alkyl esters having a linear or branched alkyl group. “(Meth) acryl” refers to “acryl” and / or “methacryl”, ie, “acryl”, “methacryl”, or both “acryl” and “methacryl”.

Examples of the (meth) acrylic acid alkyl ester include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, ( Isobutyl acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, hexyl (meth) acrylate, (meth) acrylic acid Heptyl, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, (meth) acrylic Isodecyl acid, undecyl (meth) acrylate, dodecyl (meth) acrylate Tridecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate, nonadecyl (meth) acrylate, and Examples include (meth) acrylic acid alkyl esters having an alkyl group having 1 to 20 carbon atoms, such as (meth) acrylic acid eicosyl. Of these, the (meth) acrylic acid ester is preferably a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 14 carbon atoms, more preferably methyl acrylate (MA) or acrylic acid. Ethyl (EA), n-butyl acrylate (BA), or 2-ethylhexyl acrylate (2EHA). In the acrylic copolymer of the present embodiment, one type of (meth) acrylic acid alkyl ester may be used as a main component, or two or more types of (meth) acrylic acid alkyl ester may be used.

When (meth) acrylic acid alkyl ester is employed as the acrylic monomer, the content of the (meth) acrylic acid alkyl ester in the total amount (100% by mass) of the raw material monomer component for constituting the acrylic copolymer is acrylic. From the viewpoint of appropriately expressing basic properties such as adhesive properties of the pressure-sensitive adhesive in the pressure-sensitive adhesive layer, it is preferably 50% by mass or more, more preferably 60% by mass or more, and further preferably 80% by mass or more. . Moreover, the same content rate of the said (meth) acrylic-acid alkylester is 99.5 mass% or less, From a viewpoint which the characteristic of an acrylic adhesive layer can be adjusted by mix | blending the other monomer mentioned later, Is 95% by mass or less, more preferably 90% by mass or less.

Examples of the carboxyl group-containing monomer for the carboxyl group-containing monomer unit of the acrylic copolymer include (meth) acrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, and isocrotonic acid. Of these, the carboxyl group-containing monomer is preferably acrylic acid (AA) or methacrylic acid (MAA). In the acrylic copolymer of the present embodiment, one type of carboxyl group-containing monomer may be used, or two or more types of carboxyl group-containing monomers may be used.

The content of the carboxyl group-containing monomer in the total amount (100% by mass) of the raw material monomer component for constituting the acrylic copolymer is preferably from the viewpoint of obtaining a significant interaction as a whole with the basic monomer. It is 5 mass% or more, More preferably, it is 1 mass% or more, More preferably, it is 2 mass% or more. Further, the same content of the carboxyl group-containing monomer is preferably 10% by mass or less, more preferably 9% by mass or less, from the viewpoint of suppressing an excessive influence on the basic properties of the acrylic copolymer. Preferably it is 7 mass% or less, More preferably, it is 6 mass% or less.

The acrylic copolymer may contain other monomer units in addition to the acrylic monomer unit and the carboxyl group-containing monomer unit. Suitable examples of the copolymerizable monomer for such a monomer unit include a hydroxyl group-containing monomer and a nitrogen atom-containing monomer. A hydroxyl group-containing monomer is a monomer that will have at least one hydroxyl group in the monomer unit. A nitrogen atom-containing monomer is a monomer that will have at least one nitrogen atom in the monomer unit. In the acrylic copolymer of this embodiment, as such other copolymerizable monomer, one type of monomer may be used, or two or more types of monomers may be used.

When the acrylic copolymer in the pressure-sensitive adhesive layer 1 includes a hydroxyl group-containing monomer unit, it is easy to obtain adhesiveness and appropriate cohesive force in the pressure-sensitive adhesive layer 1. Further, when the acrylic copolymer contains a hydroxyl group-containing monomer unit and the pressure-sensitive adhesive layer 1 contains a crosslinking agent such as an isocyanate-based crosslinking agent, the hydroxyl group-containing monomer unit can be crosslinked with the crosslinking agent, In the pressure-sensitive adhesive layer 1, hardness and good adhesion reliability are easily obtained. The hardness of the pressure-sensitive adhesive layer 1 contributes to an improvement in workability of the pressure-sensitive adhesive layer 1 before radiation curing and an increase in elasticity in the pressure-sensitive adhesive layer 1 after radiation curing.

Examples of the hydroxyl group-containing monomer include a hydroxyl group-containing (meth) acrylic acid ester, vinyl alcohol, and allyl alcohol. Examples of the hydroxyl group-containing (meth) acrylic acid ester include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 4- (meth) acrylic acid 4- Hydroxybutyl, 6-hydroxyhexyl (meth) acrylate, hydroxyoctyl (meth) acrylate, hydroxydecyl (meth) acrylate, hydroxylauryl (meth) acrylate, and (meth) acrylic acid (4-hydroxymethylcyclohexyl) Is mentioned. Of these, the hydroxyl group-containing monomer is preferably a hydroxyl group-containing (meth) acrylic acid ester, and more preferably 4-hydroxybutyl acrylate (4HBA).

The content ratio of the hydroxyl group-containing monomer in the total amount (100% by mass) of the raw material monomer component for constituting the acrylic copolymer is preferably 0.01% by mass or more, more preferably 0.02% by mass or more, More preferably, it is 0.03 mass% or more, More preferably, it is 0.05 mass% or more. Further, the content of the hydroxyl group-containing monomer is preferably 5% by mass or less, more preferably 3% by mass or less, and still more preferably 1% by mass or less. When the content of the hydroxyl group-containing monomer is 0.01 to 5% by mass, it is easy to obtain adhesiveness and an appropriate cohesive force in the pressure-sensitive adhesive layer 1, and the pressure-sensitive adhesive layer 1 is capable of crosslinking with an isocyanate-based crosslinking agent or the like. When an agent is included, the pressure-sensitive adhesive layer 1 can easily obtain hardness and good adhesion reliability.

When the acrylic copolymer in the pressure-sensitive adhesive layer 1 contains a nitrogen atom-containing monomer unit, it is easy to obtain hardness and good adhesion reliability in the pressure-sensitive adhesive layer 1. The hardness of the pressure-sensitive adhesive layer 1 contributes to an improvement in workability of the pressure-sensitive adhesive layer 1 before radiation curing and an increase in elasticity in the pressure-sensitive adhesive layer 1 after radiation curing. Moreover, in the case where the pressure-sensitive adhesive layer 1 includes a polyfunctional acrylic oligomer described later, the transparency of the pressure-sensitive adhesive layer 1 is improved when the acrylic copolymer includes no nitrogen atom-containing monomer unit. Tend to. This is considered to be because when the acrylic copolymer contains a nitrogen atom-containing monomer unit, the compatibility between the copolymer and the polyfunctional acrylic oligomer is improved.

Examples of nitrogen atom-containing monomers include N-vinyl cyclic amides and (meth) acrylamides.

Examples of the N-vinyl cyclic amide which is a nitrogen atom-containing monomer include N-vinyl cyclic amide represented by the following formula (1).

[In Formula (1), R ¹ represents a divalent organic group]

R ¹ in the above formula (1) is a divalent organic group, preferably a divalent saturated hydrocarbon group or an unsaturated hydrocarbon group, more preferably an alkylene group having 3 to 5 carbon atoms. .

Examples of the N-vinyl cyclic amide represented by the above formula (1) include N-vinyl-2-pyrrolidone, N-vinyl-2-piperidone, N-vinyl-3-morpholinone, and N-vinyl-2-caprolactam. N-vinyl-1,3-oxazin-2-one, and N-vinyl-3,5-morpholinedione.

Examples of (meth) acrylamides that are nitrogen atom-containing monomers include (meth) acrylamide, N-alkyl (meth) acrylamide, and N, N-dialkyl (meth) acrylamide. Examples of the N-alkyl (meth) acrylamide include N-ethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, Nn-butyl (meth) acrylamide, and N-octyl (meth) acrylamide. The N-alkyl (meth) acrylamide also includes (meth) acrylamide having an amino group such as dimethylaminoethyl (meth) acrylamide, diethylaminoethyl (meth) acrylamide, and dimethylaminopropyl (meth) acrylamide. Examples of N, N-dialkyl (meth) acrylamide include N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N, N-dipropyl (meth) acrylamide, N, N-diisopropyl ( Mention may be made of (meth) acrylamide, N, N-di (n-butyl) (meth) acrylamide, and N, N-di (t-butyl) (meth) acrylamide. Examples of (meth) acrylamides include N-hydroxyalkyl (meth) acrylamide. Examples of N-hydroxyalkyl (meth) acrylamide include N-methylol (meth) acrylamide, N- (2-hydroxyethyl) (meth) acrylamide, N- (2-hydroxypropyl) (meth) acrylamide, N- ( 1-hydroxypropyl) (meth) acrylamide, N- (3-hydroxypropyl) (meth) acrylamide, N- (2-hydroxybutyl) (meth) acrylamide, N- (3-hydroxybutyl) (meth) acrylamide, N -(4-hydroxybutyl) (meth) acrylamide and N-methyl-N-2-hydroxyethyl (meth) acrylamide. Examples of (meth) acrylamides include N-alkoxyalkyl (meth) acrylamides. Examples of N-alkoxyalkyl (meth) acrylamide include N-methoxymethyl (meth) acrylamide and N-butoxymethyl (meth) acrylamide.

Examples of nitrogen atom-containing monomers other than N-vinyl cyclic amides and (meth) acrylamides include amino group-containing monomers, cyano group-containing monomers, heterocyclic-containing monomers, imide group-containing monomers, and isocyanate group-containing monomers. Can be mentioned. Examples of the amino group-containing monomer include aminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, and t-butylaminoethyl (meth) acrylate. Examples of the cyano group-containing monomer include acrylonitrile and methacrylonitrile. Examples of the heterocyclic ring-containing monomer include (meth) acryloylmorpholine, N-vinylpiperazine, N-vinylpyrrole, N-vinylimidazole, N-vinylpyrazine, N-vinylmorpholine, N-vinylpyrazole, vinylpyridine, vinylpyrimidine, Examples include vinyl oxazole, vinyl isoxazole, vinyl thiazole, vinyl isothiazole, vinyl pyridazine, (meth) acryloyl pyrrolidone, (meth) acryloyl pyrrolidine, (meth) acryloyl piperidine, and N-methyl vinyl pyrrolidone. Examples of the imide group-containing monomer include maleimide monomers such as N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, N-phenylmaleimide, N-methylitaconimide, N-ethylitaconimide, N-butylitacon Imacone monomers such as imide, N-octylitaconimide, N-2-ethylhexylitaconimide, N-laurylitaconimide, N-cyclohexylitaconimide, N- (meth) acryloyloxymethylenesuccinimide, N- (meth) acryloyl- And succinimide monomers such as 6-oxyhexamethylene succinimide and N- (meth) acryloyl-8-oxyoctamethylene succinimide. Examples of the isocyanate group-containing monomer include 2- (meth) acryloyloxyethyl isocyanate.

The nitrogen atom-containing monomer is preferably an N-vinyl cyclic amide or (meth) acrylamide represented by the above formula (1), more preferably N-vinyl-2-pyrrolidone (NVP), N— Vinyl-2-caprolactam, N, N-dimethyl (meth) acrylamide, or N, N-diethyl (meth) acrylamide.

The content of the nitrogen atom-containing monomer in the total amount (100% by mass) of the raw material monomer component for constituting the acrylic copolymer is preferably from the viewpoint of obtaining hardness, adhesion, and sufficient transparency in the pressure-sensitive adhesive layer 1. Is 0.5% by mass or more, more preferably 1% by mass or more, and still more preferably 2% by mass or more. Further, the same content of the nitrogen atom-containing monomer is sufficient in the pressure-sensitive adhesive layer 1 from the viewpoint of obtaining sufficient transparency and suppressing the pressure-sensitive adhesive layer 1 from becoming too hard. From the viewpoint of obtaining properties, it is preferably 30% by mass or less, more preferably 25% by mass or less, and still more preferably 20% by mass or less.

The acrylic copolymer as described above can be obtained by polymerizing raw material monomer components. Examples of the polymerization technique include solution polymerization, emulsion polymerization, bulk polymerization, and polymerization by active energy ray irradiation (active energy ray polymerization). From the viewpoint of transparency and water resistance of the obtained copolymer and cost, solution polymerization is preferred.

When performing the solution polymerization, for example, esters, aromatic hydrocarbons, aliphatic hydrocarbons, alicyclic hydrocarbons, and ketones can be used as the solvent. Examples of the ester solvent include ethyl acetate and n-butyl acetate. Examples of the aromatic hydrocarbon solvent include toluene and benzene. Examples of the aliphatic hydrocarbon solvent include n-hexane and n-heptane. Examples of the alicyclic hydrocarbon solvents include cyclohexane and methylcyclohexane. Examples of the ketone solvent include methyl ethyl ketone and methyl isobutyl ketone. In solution polymerization, one type of solvent may be used, or two or more types of solvents may be used.

A polymerization initiator can be used when polymerizing the raw material monomer component to obtain an acrylic copolymer. For example, in solution polymerization, a thermal polymerization initiator can be preferably used. In the polymerization, one type of polymerization initiator may be used, or two or more types of polymerization initiators may be used.

Examples of the polymerization initiator used in the solution polymerization include azo initiators, peroxide polymerization initiators, and redox polymerization initiators. As the azo initiator, an azo initiator disclosed in JP-A-2002-69411 can be preferably used. The azo initiator is preferable because a decomposition product of the initiator hardly remains in the acrylic copolymer. Such azo initiators include 2,2′-azobisisobutyronitrile (AIBN), 2,2′-azobis-2-methylbutyronitrile (AMBN), 2,2′-azobis (2 -Methylpropionic acid) dimethyl and 4,4'-azobis-4-cyanovaleric acid. Examples of peroxide polymerization initiators include dibenzoyl peroxide and t-butyl permaleate. The amount of the polymerization initiator used may be within a range that can be used as a polymerization initiator capable of obtaining a desired copolymer molecular weight and reactivity.

The weight average molecular weight (Mw) of the acrylic copolymer obtained as described above is preferably 400,000 or more from the viewpoint of the pressure-sensitive adhesive property of the pressure-sensitive adhesive layer 1 before radiation curing and the workability of the pressure-sensitive adhesive sheet X1, More preferably, it is 600,000 or more. Further, from the viewpoint of adhesiveness of the pressure-sensitive adhesive sheet X1 to the pressure-sensitive adhesive layer 1, the weight average molecular weight of the acrylic copolymer is preferably 2 million or less, more preferably 1.5 million or less. The weight average molecular weight of the acrylic copolymer can be controlled by the type and amount of the polymerization initiator, the temperature and time during polymerization, the monomer concentration, the monomer dropping rate, and the like. Moreover, a weight average molecular weight says the value calculated by polystyrene conversion of the measured value obtained by GPC (gel permeation chromatography). Specifically, the weight average molecular weight can be measured by a method described later with reference to Examples.

The content of the acrylic copolymer in the pressure-sensitive adhesive layer 1 is 60% by mass or more based on the total amount (100% by mass) of the pressure-sensitive adhesive layer 1 from the viewpoint of obtaining sufficient adhesion reliability in the pressure-sensitive adhesive layer 1. Preferably, it is 70% by mass or more, and more preferably 80% by mass or more.

[Basic monomer]
The basic monomer contained in the pressure-sensitive adhesive layer 1 of the pressure-sensitive adhesive sheet X1 is a monomer that can be polymerized in the pressure-sensitive adhesive layer 1, and in this embodiment, the pH of the aqueous monomer solution measured by the method described later in connection with the examples described later. Is a monomer having a value of 8.0 or more. From the viewpoint of realizing sufficient acid-base interaction with the carboxyl group-containing monomer unit of the acrylic copolymer in the pressure-sensitive adhesive layer 1, the basic monomer has an acid dissociation constant pKa of 8.0 or more. Preferably, it has at least one of an amide group and an amino group in the molecule. Moreover, it is preferable that a basic monomer is a high boiling-point material which does not volatilize at the drying temperature at the time of adhesive sheet preparation. From such a viewpoint, the boiling point of the basic monomer at normal pressure is preferably 120 ° C. or higher, more preferably 130 ° C. or higher.

Examples of the basic monomer include a compound group represented by the following formula (2) and a compound group represented by the following formula (3).

R ³ in the formula (2) and R ⁷ in the formula (3) each represent a linear or branched alkylene group having 2 to 6 carbon atoms, such as an ethylene group, a propylene group, or a butylene group. It is. R ⁴ and R ⁵ in formula (2) may be bonded to each other to form a ring (for example, pyrrolidine ring, piperidine ring, morpholine ring) with an adjacent nitrogen atom. R ⁸ and R ⁹ in formula (3) may be bonded to each other to form a ring (for example, a pyrrolidine ring, a piperidine ring, or a morpholine ring) with an adjacent nitrogen atom.

Examples of the compound represented by the above formula (2) include N- (dialkylaminoalkyl) (meth) acrylamide and N- (aminoalkyl) (meth) acrylamide. Examples of N- (dialkylaminoalkyl) (meth) acrylamide include N- (2-dimethylaminoethyl) (meth) acrylamide, N- (2-diethylaminoethyl) (meth) acrylamide, and N- (3-dimethylamino). Propyl) (meth) acrylamide, and N- (3-diethylaminopropyl) (meth) acrylamide. Examples of N- (aminoalkyl) (meth) acrylamide include N- (2-aminoethyl) (meth) acrylamide and N- (3-aminopropyl) (meth) acrylamide.

Examples of the compound represented by the above formula (3) include dialkylaminoalkyl (meth) acrylate and aminoalkyl (meth) acrylate. Examples of the dialkylaminoalkyl (meth) acrylate include 2-dimethylaminoethyl (meth) acrylate, 2-diethylaminoethyl (meth) acrylate, 3-dimethylaminopropyl (meth) acrylate, and 3-diethylaminopropyl (meth) acrylic. Rate. Examples of aminoalkyl (meth) acrylates include 2-aminoethyl (meth) acrylate and 3-aminopropyl (meth) acrylate.

The basic monomer contained in the pressure-sensitive adhesive layer 1 is preferably N- (3-dimethylaminopropyl) methacrylamide (DMAPMA, boiling point 134 ° C. [pressure 2 mmHg], pKa 9.30), N- (3-dimethylamino). Propyl) acrylamide (DMAPAA, boiling point 117 ° C. [pressure 2 mmHg], pKa 10.35), and 2-dimethylaminoethyl methacrylate (DMAEMA, boiling point 186 ° C. [pressure 1 mmHg]). In the pressure-sensitive adhesive layer 1, one type of basic monomer may be included, or two or more types of basic monomers may be included.

The content of the basic monomer in the pressure-sensitive adhesive layer 1 is 0.1 parts by mass or more based on 100 parts by mass of the acrylic copolymer from the viewpoint of the hardness of the pressure-sensitive adhesive layer 1 after curing and the ease of obtaining strong adhesiveness. Preferably, it is 1 part by mass or more, and more preferably 2 parts by mass or more. Further, from the viewpoint of suppressing a decrease in adhesion reliability of the pressure-sensitive adhesive layer 1 after curing, the same content of the basic monomer is preferably 20 parts by mass or less with respect to 100 parts by mass of the acrylic copolymer, More preferably, it is 10 parts by mass or less.

The mass ratio of the basic monomer in the pressure-sensitive adhesive layer 1 to the carboxyl group-containing monomer contained in the raw material monomer component for forming the above-mentioned acrylic copolymer in the pressure-sensitive adhesive layer 1 is that of the pressure-sensitive adhesive layer 1 after curing. From the viewpoint of ease of obtaining hardness and strong adhesiveness, it is preferably 0.01 or more, more preferably 0.02 or more, more preferably 0.1 or more, and further preferably 0.25 or more. is there. Further, from the viewpoint of suppressing a decrease in the adhesion reliability of the pressure-sensitive adhesive layer 1 after curing, the same mass ratio is preferably 40 or less, more preferably 10 or less, more preferably 5 or less, and further Preferably it is 2.5 or less.

(Photopolymerization initiator)
The photopolymerization initiator contained in the pressure-sensitive adhesive layer 1 of the pressure-sensitive adhesive sheet X1 is an element for initiating a polymerization reaction in the pressure-sensitive adhesive layer 1 upon receiving radiation. Examples of the photopolymerization initiator include a benzoin ether photopolymerization initiator, an acetophenone photopolymerization initiator, an α-ketol photopolymerization initiator, an aromatic sulfonyl chloride photopolymerization initiator, and a photoactive oxime photopolymerization initiator. Agents, benzoin photopolymerization initiators, benzyl photopolymerization initiators, benzophenone photopolymerization initiators, ketal photopolymerization initiators, thioxanthone photopolymerization initiators, and acylphosphine oxide photopolymerization initiators. . In the pressure-sensitive adhesive layer 1, one type of photopolymerization initiator may be used, or two or more types of photopolymerization initiators may be used.

Examples of the benzoin ether photopolymerization initiator include benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, and 2,2-dimethoxy-1,2-diphenylethane-1-one ( Trade name “Irgacure 651” manufactured by BASF). Examples of the acetophenone photopolymerization initiator include 1-hydroxycyclohexyl phenyl ketone (trade name “Irgacure 184”, manufactured by BASF), 4-phenoxydichloroacetophenone, 4-t-butyl-dichloroacetophenone, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one (trade name “Irgacure 2959”, manufactured by BASF), 2-hydroxy-2-methyl-1-phenyl- Propan-1-one (trade name “Darocur 1173”, manufactured by BASF) and methoxyacetophenone. Examples of α-ketol photopolymerization initiators include 2-methyl-2-hydroxypropiophenone and 1- [4- (2-hydroxyethyl) -phenyl] -2-hydroxy-2-methylpropane-1- ON. Examples of the aromatic sulfonyl chloride photopolymerization initiator include 2-naphthalenesulfonyl chloride. Examples of the photoactive oxime photopolymerization initiator include 1-phenyl-1,2-propanedione-2- (O-ethoxycarbonyl) -oxime. Examples of the benzoin photopolymerization initiator include benzoin. Examples of the benzyl photopolymerization initiator include benzyl. Examples of the benzophenone photopolymerization initiator include benzophenone, benzoylbenzoic acid, 3,3′-dimethyl-4-methoxybenzophenone, polyvinylbenzophenone, and α-hydroxycyclohexyl phenyl ketone. Examples of the ketal photopolymerization initiator include benzyl dimethyl ketal. Examples of the thioxanthone photopolymerization initiator include thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, isopropylthioxanthone, Examples include 2,4-diisopropylthioxanthone and dodecylthioxanthone. Examples of the acylphosphine photopolymerization initiator include bis (2,6-dimethoxybenzoyl) phenylphosphine oxide, bis (2,6-dimethoxybenzoyl) (2,4,4-trimethylpentyl) phosphine oxide, bis ( 2,6-dimethoxybenzoyl) -n-butylphosphine oxide, bis (2,6-dimethoxybenzoyl)-(2-methylpropan-1-yl) phosphine oxide, bis (2,6-dimethoxybenzoyl)-(1- Methylpropan-1-yl) phosphine oxide, bis (2,6-dimethoxybenzoyl) -t-butylphosphine oxide, bis (2,6-dimethoxybenzoyl) cyclohexylphosphine oxide, bis (2,6-dimethoxybenzoyl) octylphosphine Oxides, bis (2-mes Xylbenzoyl) (2-methylpropan-1-yl) phosphine oxide, bis (2-methoxybenzoyl) (1-methylpropan-1-yl) phosphine oxide, bis (2,6-diethoxybenzoyl) (2-methyl Propan-1-yl) phosphine oxide, bis (2,6-diethoxybenzoyl) (1-methylpropan-1-yl) phosphine oxide, bis (2,6-dibutoxybenzoyl) (2-methylpropane-1- Yl) phosphine oxide, bis (2,4-dimethoxybenzoyl) (2-methylpropan-1-yl) phosphine oxide, bis (2,4,6-trimethylbenzoyl) (2,4-dipentoxyphenyl) phosphine oxide Bis (2,6-dimethoxybenzoyl) benzylphosphine oxide, bis ( , 6-Dimethoxybenzoyl) -2-phenylpropylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2-phenylethylphosphine oxide, bis (2,6-dimethoxybenzoyl) benzylphosphine oxide, bis (2,6- Dimethoxybenzoyl) -2-phenylpropylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2-phenylethylphosphine oxide, 2,6-dimethoxybenzoylbenzylbutylphosphine oxide, 2,6-dimethoxybenzoylbenzyloctylphosphine oxide, Bis (2,4,6-trimethylbenzoyl) -2,5-diisopropylphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -2-methylphenylphosphine oxide, bis (2, , 6-trimethylbenzoyl) -4-methylphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -2,5-diethylphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -2,3 , 5,6-tetramethylphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -2,4-di-n-butoxyphenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide (trade name) “Irgacure 819” (manufactured by BASF), bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, bis (2,4,6-trimethylbenzoyl) isobutylphosphine oxide, 2,6- Dimethoxyoxybenzoyl-2,4,6-trimethylbenzoyl n-butylphosphine oxide, bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -2,4-dibutoxyphenylphosphine oxide, 1,10-bis [bis (2,4,6-trimethylbenzoyl) phosphine oxide] decane, and tri (2-methylbenzoyl) phosphine oxide.

The content of the photopolymerization initiator in the pressure-sensitive adhesive layer 1 is 0.05 parts by mass or more with respect to 100 parts by mass of the acrylic copolymer from the viewpoint of realizing a sufficient reaction rate and reaction rate for the curing reaction. Is preferable, more preferably 0.1 parts by mass or more, and still more preferably 0.2 parts by mass or more. In addition, from the viewpoint of suppressing the problem that the pressure-sensitive adhesive layer 1 is not sufficiently cured by irradiation, the content of the photopolymerization initiator in the pressure-sensitive adhesive layer 1 is based on 100 parts by mass of the acrylic copolymer. The amount is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, and still more preferably 0.8 parts by mass or less.

[Multifunctional acrylic oligomer]
In addition to the above-mentioned acrylic copolymer, basic monomer, and photopolymerization initiator, the pressure-sensitive adhesive layer 1 of the pressure-sensitive adhesive sheet X1 may further contain a polyfunctional acrylic oligomer. The polyfunctional acrylic oligomer is a compound that can be polymerized in the pressure-sensitive adhesive layer 1 and includes two or more repeating units and has two or more (meth) acryloyl groups. That is, the polyfunctional acrylic oligomer is a polymer having two or more (meth) acryloyl groups in the molecule. The “(meth) acryloyl group” represents “acryloyl group” and / or “methacryloyl group”, that is, “acryloyl group”, “methacryloyl group”, or both “acryloyl group” and “methacryloyl group”. In the adhesive layer 1, one type of polyfunctional acrylic oligomer may be used, or two or more types of polyfunctional acrylic oligomers may be used.

As polyfunctional acrylic oligomers, for example, polyester (meth) acrylates with two or more (meth) acryloyl groups added as functional groups to the polyester skeleton, and two or more (meth) acryloyl groups as functional groups added to the epoxy skeleton Epoxy (meth) acrylate, urethane (meth) acrylate in which two or more (meth) acryloyl groups are added as a functional group to the skeleton of urethane, and EO adduct diacrylate of bisphenol A.

Polyester (meth) acrylate is obtained, for example, by reacting (meth) acrylic acid with a terminal hydroxyl group of polyester obtained by polymerizing polyhydric alcohol and polycarboxylic acid. Specific examples of the polyester (meth) acrylate include Aronix M-6000, Aronix M-7000, Aronix M-8000, and Aronix M-9000 manufactured by Toa Gosei Co., Ltd.

Epoxy (meth) acrylate is obtained, for example, by reacting (meth) acrylic acid with an epoxy resin. Specific examples of the epoxy (meth) acrylate include Lipoxy SP, Lipoxy VR manufactured by Showa Polymer Co., Ltd., and Epoxy Ester Series manufactured by Kyoeisha Chemical Co., Ltd.

Urethane (meth) acrylate is obtained, for example, by reacting polyol, polyisocyanate, and hydroxy (meth) acrylate. Examples of the polyisocyanate include toluene diisocyanate, isophorone diisocyanate, and hexamethylene diisocyanate. Examples of the urethane (meth) acrylate include Art Resin UN series manufactured by Negami Kogyo Co., Ltd., NK Oligo U series manufactured by Shin-Nakamura Chemical Co., Ltd., and Purple Light UV Series manufactured by Nippon Synthetic Chemical Industry Co., Ltd.

The number of (meth) acryloyl groups (number of functional groups) in the molecule in the polyfunctional acrylic oligomer is preferably 3 or more from the viewpoint of coherence of the adhesion reliability of the pressure-sensitive adhesive layer 1 and the hardness of the pressure-sensitive adhesive layer 1 after curing. Yes, more preferably 5 or more. From the viewpoint of obtaining good adhesion to the adherend in the pressure-sensitive adhesive layer 1, the number of (meth) acryloyl groups in the molecule in the polyfunctional acrylic oligomer is preferably 15 or less, more preferably 12 or less. .

The weight average molecular weight of the polyfunctional acrylic oligomer is preferably 500 from the viewpoint of securing processability in the pressure-sensitive adhesive sheet X1 before the pressure-sensitive adhesive layer 1 is cured, and from the viewpoint of suppressing a decrease in adhesion reliability of the pressure-sensitive adhesive layer 1. It is above, More preferably, it is 600 or more, More preferably, it is 700 or more. Further, the weight average molecular weight of the polyfunctional acrylic oligomer is preferably 30000 or less, more preferably 20000 or less, and still more preferably 10,000 or less, from the viewpoint of obtaining sufficient hardness in the pressure-sensitive adhesive layer 1 after curing. . The weight average molecular weight of the polyfunctional oligomer can be determined by, for example, high performance liquid chromatography (HPLC). For example, HPLC 8020 manufactured by Tosoh Corporation is used as the apparatus, TSKgel GMH _HR -H (S) (20) × 2 is used as the column, tetrahydrofuran is used as the solvent, and the flow rate is 0.5 mL / min. Thus, the weight average molecular weight can be measured.

From the viewpoint of improving the hardness of the pressure-sensitive adhesive layer 1, the hardness of the polyfunctional acrylic oligomer homopolymer is preferably 4B or more, more preferably HB or more, and still more preferably H or more. The above hardness is so-called pencil hardness, and can be measured according to the scratch hardness test (pencil method) described in JIS K5600-5-4.

The content of the polyfunctional acrylic oligomer in the pressure-sensitive adhesive layer 1 of the pressure-sensitive adhesive sheet X1 is a pressure-sensitive adhesive from the viewpoint of obtaining adhesiveness in the pressure-sensitive adhesive layer 1 and obtaining good hardness in the pressure-sensitive adhesive layer 1 after curing. It is preferable that it is 0.05 mass part or more with respect to 100 mass parts of acrylic copolymers in the agent layer 1, More preferably, it is 3 mass parts or more, More preferably, it is 5 mass parts or more. In addition, from the viewpoint of suppressing a decrease in the adhesion reliability of the pressure-sensitive adhesive layer 1 and from the viewpoint of handleability of the pressure-sensitive adhesive sheet X1, the content of the polyfunctional acrylic oligomer in the pressure-sensitive adhesive layer 1 is 100 parts by mass of the acrylic copolymer. It is preferable that it is 40 mass parts or less with respect to it, More preferably, it is 35 mass parts or less, More preferably, it is 30 mass parts or less.

[Crosslinking agent]
The pressure-sensitive adhesive layer 1 of the pressure-sensitive adhesive sheet X1 may further contain a crosslinking agent. By the crosslinking agent, cohesive force can be imparted to the pressure-sensitive adhesive layer 1 before radiation curing, and good processability and adhesiveness can be easily obtained in the pressure-sensitive adhesive sheet X1. In the pressure-sensitive adhesive layer 1, one type of crosslinking agent may be used, or two or more types of crosslinking agents may be used.

Examples of the crosslinking agent include an isocyanate crosslinking agent, an epoxy crosslinking agent, a melamine crosslinking agent, a peroxide crosslinking agent, a urea crosslinking agent, a metal alkoxide crosslinking agent, a metal chelate crosslinking agent, and a metal salt crosslinking agent. Agents, carbodiimide crosslinking agents, oxazoline crosslinking agents, aziridine crosslinking agents, and amine crosslinking agents.

Examples of the isocyanate crosslinking agent (polyfunctional isocyanate compound) include lower aliphatic polyisocyanates, alicyclic polyisocyanates, and aromatic polyisocyanates. Examples of the lower aliphatic polyisocyanates include 1,2-ethylene diisocyanate, 1,4-butylene diisocyanate, and 1,6-hexamethylene diisocyanate. Examples of the alicyclic polyisocyanates include cyclopentylene diisocyanate, cyclohexylene diisocyanate, isophorone diisocyanate, hydrogenated tolylene diisocyanate, and hydrogenated xylene diisocyanate. Examples of aromatic polyisocyanates include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, and xylylene diisocyanate. Specifically, as the isocyanate-based crosslinking agent, trimethylolpropane / tolylene diisocyanate adduct (trade name “Coronate L”, manufactured by Nippon Polyurethane Industry Co., Ltd.), trimethylolpropane / hexamethylene diisocyanate adduct (trade name “ Coronate HL ”, manufactured by Nippon Polyurethane Industry Co., Ltd., trimethylolpropane / xylylene diisocyanate adduct (trade name“ Takenate 110N ”, manufactured by Mitsui Chemicals, Inc.) Product name “Duranate”, manufactured by Asahi Kasei Chemicals Corporation).

Examples of the epoxy crosslinking agent (polyfunctional epoxy compound) include N, N, N ′, N′-tetraglycidyl-m-xylenediamine, diglycidylaniline, and 1,3-bis (N, N-diglycidylamino). Methyl) cyclohexane, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, sorbitol polyglycidyl ether, Glycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitan polyglycidyl ether, trimethy Propanepolyglycidyl ether, adipic acid diglycidyl ester, o-phthalic acid diglycidyl ester, triglycidyl-tris (2-hydroxyethyl) isocyanurate, resorcin diglycidyl ether, bisphenol-S-diglycidyl ether, molecule Examples thereof include an epoxy resin having two or more epoxy groups. Specifically, as the epoxy-based crosslinking agent, trade name “Tetrad C” manufactured by Mitsubishi Gas Chemical Co., Ltd. may be mentioned.

The content of the crosslinking agent in the pressure-sensitive adhesive layer 1 is preferably such an amount that the gel fraction of the pressure-sensitive adhesive layer 1 before curing by radiation irradiation is 10% (mass%) or more. When the gel fraction of the pressure-sensitive adhesive layer 1 before curing is 10% or more, a sufficient cohesive force can be obtained with the pressure-sensitive adhesive layer 1, good workability can be easily obtained in the pressure-sensitive adhesive sheet X1, and adhesiveness can also be obtained. It is easy to be done. Specifically, the content of the crosslinking agent depends on the molecular weight of the acrylic copolymer, the composition of the monomer unit constituting the acrylic copolymer, the type of the crosslinking agent, etc., based on 100 parts by mass of the acrylic copolymer. The amount is preferably 0.05 to 5 parts by mass, more preferably 0.1 to 3 parts by mass.

[Other contents]
The pressure-sensitive adhesive layer 1 of the pressure-sensitive adhesive sheet X1 may contain other additives as long as the effects of the present invention are not impaired. Examples of such additives include tackifiers, silane coupling agents, colorants, pigments, dyes, surfactants, plasticizers, surface lubricants, leveling agents, softeners, antioxidants, and anti-aging agents. , Light stabilizers, polymerization inhibitors, inorganic or organic fillers, metal powders, particulates, and foils. The content of these additives is determined according to the purpose of use, and is, for example, 10 parts by mass or less with respect to 100 parts by mass of the acrylic copolymer as long as the effects of the present invention are not impaired.

〔separator〕
The adhesive sheet X1 may be provided with a separator (release liner) on the adhesive surface. The separator is an element for protecting the pressure-sensitive adhesive layer 1 of the pressure-sensitive adhesive sheet X1 from being exposed, and is peeled off from the pressure-sensitive adhesive sheet X1 when the pressure-sensitive adhesive sheet X1 is attached to an adherend. The pressure-sensitive adhesive sheet X1 or the pressure-sensitive adhesive layer 1 may be sandwiched between two separators, or the pressure-sensitive adhesive sheet X1 or the pressure-sensitive adhesive layer 1 is rolled with a separator so that the pressure-sensitive adhesive sheets X1 and the separator are alternately arranged. You may take the form wound by the shape.

Examples of the separator include a substrate having a release treatment layer, a low adhesive substrate made of a fluoropolymer, and a low adhesive substrate made of a nonpolar polymer. Examples of the substrate having a release treatment layer include plastic films and paper surface-treated with a release treatment agent such as silicone-based, long-chain alkyl-based, fluorine-based, and molybdenum sulfide. Examples of the fluorine-based polymer constituting the low adhesion substrate include polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, tetrafluoroethylene-hexafluoropropylene copolymer, and chlorofluoroethylene- A vinylidene fluoride copolymer is mentioned. Examples of the nonpolar polymer that forms the low-adhesive substrate include olefin-based resins (for example, polyethylene and polypropylene). Examples of the plastic film constituting the substrate having a release treatment layer include, for example, a polyolefin film, a polyester film, a vinyl chloride resin film, a vinyl acetate resin film, a polyimide resin film, a polyamide resin film, a fluorine resin film, and Cellophanes are listed.

The surface of such a separator may be subjected to release treatment, antifouling treatment, or antistatic treatment. For the release treatment, a silicone-based, fluorine-based, long-chain alkyl-based, or fatty acid amide-based release agent, or silica powder can be used. Silica powder can be used for the antifouling treatment. As the antistatic treatment, a coating type, kneading type, or vapor deposition type antistatic treatment can be employed. The thickness of the separator is, for example, 5 to 200 μm.

[Method for producing adhesive sheet]
The pressure-sensitive adhesive sheet X1 to the pressure-sensitive adhesive layer 1 are prepared, for example, by preparing a pressure-sensitive adhesive composition for forming a pressure-sensitive adhesive layer, applying the pressure-sensitive adhesive composition to a separator (release liner), and drying the pressure-sensitive adhesive composition on the separator. Can be produced or formed.

The pressure-sensitive adhesive composition to be applied to the separator is prepared, for example, as a solvent-type pressure-sensitive adhesive composition. Specifically, in a predetermined solvent, the above-mentioned acrylic copolymer, basic monomer, and photopolymerization initiator, and the above-mentioned polyfunctional acrylic oligomer, cross-linking agent and other elements added as necessary, Mix together. When an acrylic copolymer obtained by solution polymerization is used, a basic monomer and a photopolymerization initiator are added to the polymerization solvent containing the acrylic copolymer, if necessary, and then, and The above-mentioned polyfunctional acrylic oligomer, crosslinking agent and other elements which are added as necessary are mixed.

In the coating step, the prepared pressure-sensitive adhesive composition is applied to the separator to form a coating layer (pressure-sensitive adhesive composition layer). Application methods include, for example, comma coat, roll coat, kiss roll coat, gravure coat, reverse coat, roll brush, spray coat, dip roll coat, bar coat, knife coat, air knife coat, curtain coat, lip coat, and And extrusion coating with a die coater or the like.

In the drying step, the coating layer formed on the separator is heated and dried to remove the solvent and the like from the coating layer. From the viewpoint of forming the pressure-sensitive adhesive layer 1 having good pressure-sensitive adhesive properties, the heating and drying temperature is preferably selected in the range of 50 to 120 ° C. The heat drying time is preferably 5 seconds to 20 minutes. In the case where the pressure-sensitive adhesive layer 1 contains a crosslinking agent, the temperature and time of heat drying such that the crosslinking reaction proceeds in the pressure-sensitive adhesive layer 1 are employed. The coating amount in the above coating step and the temperature and time of heat drying in this drying step are appropriately set so that the thickness of the pressure-sensitive adhesive layer 1 is, for example, 1 to 300 μm after the drying step. Is done. After such a drying step, a separator may be further provided on the exposed surface of the pressure-sensitive adhesive layer 1. The adhesive sheet X1 can be manufactured as described above.

[Use of adhesive sheet]
The adhesive sheet X1 can be used as follows, for example. First, the adhesive sheet X1 is interposed between members to be joined, and the members are temporarily fixed. Thereafter, the pressure-sensitive adhesive layer 1 of the pressure-sensitive adhesive sheet X1 is cured by irradiation with radiation. The reaction in which the basic monomer is polymerized by radiation irradiation is initiated by the photopolymerization initiator, and the pressure-sensitive adhesive layer 1 is cured by the polymerization of the basic monomer in the pressure-sensitive adhesive layer 1. Moreover, when the above-mentioned polyfunctional acrylic oligomer is contained in the pressure-sensitive adhesive layer 1, the reaction of polymerization of the polyfunctional acrylic oligomer is also initiated by the photopolymerization initiator. The copolymerization reaction of the acrylic oligomer proceeds. Examples of the radiation for curing include ionizing radiation such as α rays, β rays, γ rays, X rays, neutron rays, and electron beams, and ultraviolet rays. From the viewpoint of cost, ultraviolet rays are preferable. More preferred is ultraviolet light having a wavelength of 200 to 420 nm. As the light source for ultraviolet irradiation, for example, a high pressure mercury lamp, a low pressure mercury lamp, a microwave excitation lamp, a metal halide lamp, a chemical lamp, a black light, or an LED can be used. Further, the irradiation energy, irradiation time, and irradiation method of the curing radiation can be appropriately set as long as the pressure-sensitive adhesive layer 1 can be cured and does not unduly affect the adherend. For example, when employing ultraviolet rays as curing radiation, the amount of irradiation (integrated quantity of light) is preferably ^{1000mJ / cm 2 ~ 10000mJ / cm} 2, more preferably ^{2000mJ / cm 2 ~ 4000mJ / cm} 2.

In the pressure sensitive adhesive sheet X1 as described above, since the pressure sensitive adhesive layer 1 contains an acrylic copolymer as a main agent, basic characteristics such as adhesiveness of the acrylic pressure sensitive adhesive can be reflected in the pressure sensitive adhesive layer 1. In addition, since the pressure-sensitive adhesive layer 1 contains a polymerizable monomer and a photopolymerization initiator and can be cured by irradiation, the pressure-sensitive adhesive layer 1 is cured or made highly elastic as described above by the curing. Can be made. In the pressure-sensitive adhesive layer 1 of the pressure-sensitive adhesive sheet X1, a basic monomer is present as a polymerizable monomer, and a carboxyl group-containing monomer capable of acid-base interaction with the monomer is included as a monomer unit of an acrylic copolymer. It is. Therefore, the polymer formed by polymerizing the basic monomer in the pressure-sensitive adhesive layer 1 through radiation irradiation contributes to the increase in elasticity of the pressure-sensitive adhesive layer 1, and a plurality of polymers between the acrylic copolymer and the acrylic copolymer. It contributes also to the adhesiveness of the adhesive layer 1 after hardening by acid-base interaction in a location. That is, in the pressure-sensitive adhesive layer 1 after curing of the pressure-sensitive adhesive sheet X1, adhesiveness and high elasticity can be obtained efficiently. In addition, the acrylic copolymer in the pressure-sensitive adhesive layer 1 of the pressure-sensitive adhesive sheet X1 is a monomer containing a carboxyl group-containing monomer whose content in the raw material monomer component for forming the copolymer is 0.5 to 10% by mass. Include as a unit. Since the acrylic copolymer in the pressure-sensitive adhesive layer 1 contains a carboxyl group-containing monomer unit within such a ratio, the pressure-sensitive adhesive layer 1 remains the acrylic monomer unit as the main element of the acrylic copolymer even after curing. It is easy to appropriately reflect basic characteristics such as adhesion mainly due to the above. Therefore, the pressure-sensitive adhesive sheet X1 is suitable for realizing a high elastic modulus with a good adhesive force in the pressure-sensitive adhesive layer 1. Such an adhesive sheet X1 is suitable for transmitting an external force to an adherend when an external force is applied. For example, in a state where the adhesive sheet X1 is cured by radiation irradiation between the first member and the second member and the first and second members are joined, the force acting on one member is the adhesive sheet X1. It can be efficiently transmitted to the other member via.

FIG. 2 is a cross-sectional view of an adhesive sheet X2 according to another embodiment of the present invention. The pressure-sensitive adhesive sheet X2 has a laminated structure including two pressure-sensitive adhesive layers 1 and a substrate 2. The upper surface and the lower surface in the figure of the pressure-sensitive adhesive layer 1 form the pressure-sensitive adhesive surface of the pressure-sensitive adhesive sheet X2. That is, the pressure-sensitive adhesive sheet X2 of this embodiment is a double-sided pressure-sensitive adhesive sheet having a pressure-sensitive adhesive surface on both sides, and is a pressure-sensitive adhesive sheet with a base material having a base material. Further, the thickness of the pressure-sensitive adhesive sheet X2 is set according to the application, and is, for example, 10 to 300 μm.

Each pressure-sensitive adhesive layer 1 of the pressure-sensitive adhesive sheet X2 has the same configuration as described above with respect to the pressure-sensitive adhesive layer 1 of the pressure-sensitive adhesive sheet X1, and can be cured by radiation irradiation. One pressure-sensitive adhesive layer 1 and the other pressure-sensitive adhesive layer 1 may be formed from the same pressure-sensitive adhesive composition, or may be formed from different pressure-sensitive adhesive compositions. .

The base material 2 of the pressure-sensitive adhesive sheet X2 is a part that functions as a support during use as well as when the pressure-sensitive adhesive sheet X2 is not used. When the pressure-sensitive adhesive sheet X2 is attached to the adherend, it is attached together with the pressure-sensitive adhesive layer 1. It is a part attached to the body.

Examples of the substrate 2 include a plastic film, a porous material, a net, a rubber sheet, a foamed sheet, a metal foil, and a laminate of two or more materials selected from these. Examples of the plastic film include polyolefin films, polyester films, vinyl chloride resin films, vinyl acetate resin films, polyimide resin films, polyamide resin films, fluorine resin films, and cellophanes. Examples of the polyolefin film include a polyethylene film, a polypropylene film, and a film made of an ethylene-propylene copolymer. Examples of the polyester film include a polyethylene terephthalate film. Examples of the porous material include paper such as Japanese paper, kraft paper, glassine paper, high quality paper, synthetic paper, and top coat paper, and cloth such as woven fabric and non-woven fabric. Examples of the fiber material constituting the fabric include cotton fiber, sufu, manila hemp, pulp, rayon, acetate fiber, polyester fiber, polyvinyl alcohol fiber, polyamide fiber, and polyolefin fiber. Examples of the rubber constituting the rubber sheet include natural rubber and butyl rubber. Examples of the foam constituting the foam sheet include a foam made of polyurethane or polychloroprene rubber. As metal foil, aluminum foil and copper foil are mentioned, for example. For the substrate 2, as necessary, fillers (inorganic fillers, organic fillers, etc.), anti-aging agents, antioxidants, ultraviolet absorbers, lubricants, plasticizers, colorants (pigments, dyes, etc.), etc. These various additives may be blended. Further, the surface of the substrate 2 may be subjected to a surface treatment. For example, physical treatment such as corona discharge treatment or plasma treatment, undercoat treatment, and chemical treatment such as back treatment may be performed on the surface of the substrate 2.

The base material 2 may have a single layer structure or a laminated structure. The thickness of the substrate 2 is, for example, 1 to 200 μm. Moreover, it is preferable that the base material 2 has sufficient radiation transmittance from a viewpoint that sufficient hardening reaction is produced in the adhesive layer 1 of the adhesive sheet X2 by radiation irradiation. For example, the light transmittance of the substrate 2 in the wavelength range of 200 to 420 nm is preferably 50% or more.

〔separator〕
The adhesive sheet X2 may be provided with a separator on the adhesive surface. The separator is a member for protecting both the pressure-sensitive adhesive layers 1 of the pressure-sensitive adhesive sheet X2 from being exposed, and is peeled off from the pressure-sensitive adhesive sheet X2 when the pressure-sensitive adhesive sheet X2 is attached to an adherend. The pressure-sensitive adhesive sheet X2 may be sandwiched between two separators, or the pressure-sensitive adhesive sheet X2 may be wound in a roll with a separator so that the pressure-sensitive adhesive sheets X2 and the separator are alternately arranged. . As a separator, the thing similar to what was mentioned above as a separator for adhesive sheets X1 can be used.

[Method for producing adhesive sheet]
The pressure-sensitive adhesive sheet X2 is prepared by, for example, preparing two pressure-sensitive adhesive layers 1 formed on the separator in the same manner as the manufacturing method described above for the pressure-sensitive adhesive sheet X1, and attaching one pressure-sensitive adhesive layer 1 to each of both surfaces of the substrate 2. By combining, it can be manufactured or formed. The pressure-sensitive adhesive sheet X2 is also produced or formed by applying a pressure-sensitive adhesive composition prepared for forming a pressure-sensitive adhesive layer on both surfaces of the substrate 2 and drying the pressure-sensitive adhesive composition on the substrate 2. be able to. For each step of preparation, application, and drying of the pressure-sensitive adhesive composition, specifically, the same method as described above can be adopted as the method for producing the pressure-sensitive adhesive sheet X1. The adhesive sheet X2 can be manufactured as described above.

[Use of adhesive sheet]
The adhesive sheet X2 can be used as follows, for example. First, the adhesive sheet X2 is interposed between members to be joined, and the members are temporarily fixed. Thereafter, both pressure-sensitive adhesive layers 1 of the pressure-sensitive adhesive sheet X2 are cured by irradiation with radiation. As the curing radiation, the same radiation as the curing radiation described above with respect to the pressure-sensitive adhesive sheet X1 can be employed.

The pressure-sensitive adhesive sheet X2 has the pressure-sensitive adhesive layer 1 similar to the pressure-sensitive adhesive layer 1 of the pressure-sensitive adhesive sheet X1, and therefore the pressure-sensitive adhesive sheet X2 is the pressure-sensitive adhesive for the same reason as described above with respect to the pressure-sensitive adhesive sheet X1. Suitable for realizing a high modulus of elasticity with good adhesion in the layer 1. Such an adhesive sheet X2 is suitable for transmitting the external force to the adherend when an external force is applied. For example, in a state where the adhesive sheet X2 is cured by radiation irradiation between the first member and the second member and the first and second members are joined, the force acting on one member is the adhesive sheet X2. It can be efficiently transmitted to the other member via.

FIG. 3 is a cross-sectional view of an adhesive sheet X3 according to another embodiment of the present invention. The pressure-sensitive adhesive sheet X3 has a laminated structure including the pressure-sensitive adhesive layer 1 and the substrate 2. The upper surface in the figure of the pressure-sensitive adhesive layer 1 forms the pressure-sensitive adhesive surface of the pressure-sensitive adhesive sheet X3. That is, the pressure-sensitive adhesive sheet X3 of the present embodiment is a single-sided pressure-sensitive adhesive sheet having a pressure-sensitive adhesive surface on one side, and is a pressure-sensitive adhesive sheet with a base material having a base material. Further, the thickness of the pressure-sensitive adhesive sheet X3 is set according to the application, and is, for example, 10 to 300 μm.

The pressure-sensitive adhesive layer 1 of the pressure-sensitive adhesive sheet X3 has the same configuration as described above with respect to the pressure-sensitive adhesive layer 1 of the pressure-sensitive adhesive sheet X1, and can be cured by radiation irradiation. The base material 2 of the pressure-sensitive adhesive sheet X3 is a part that functions as a support during use as well as when the pressure-sensitive adhesive sheet X3 is not used, and has the same configuration as described above with respect to the base material 2 of the pressure-sensitive adhesive sheet X2. Moreover, the adhesive sheet X3 may be provided with a separator on the adhesive surface. In this case, for example, the pressure-sensitive adhesive layer 1 is sandwiched between the separator and the substrate 2. As a separator, the thing similar to what was mentioned above as a separator for adhesive sheets X1 can be used. For example, the pressure-sensitive adhesive sheet X <b> 3 may be wound in a roll shape so that the pressure-sensitive adhesive layers 1 and the base materials 2 are alternately arranged without providing the separator.

[Method for producing adhesive sheet]
The pressure-sensitive adhesive sheet X3 is produced, for example, by preparing the pressure-sensitive adhesive layer 1 formed on the separator in the same manner as the manufacturing method described above for the pressure-sensitive adhesive sheet X1 and bonding the pressure-sensitive adhesive layer 1 to one side of the substrate 2. Or can be formed. The pressure-sensitive adhesive sheet X3 is also produced or formed by applying a pressure-sensitive adhesive composition prepared for forming a pressure-sensitive adhesive layer on both surfaces of the substrate 2 and drying the pressure-sensitive adhesive composition on the substrate 2. be able to. For each step of preparation, application, and drying of the pressure-sensitive adhesive composition, specifically, the same method as described above can be adopted as the method for producing the pressure-sensitive adhesive sheet X1. The adhesive sheet X3 can be manufactured as described above.

[Use of adhesive sheet]
The adhesive sheet X3 can be used as follows, for example. First, the adhesive sheet X3 is bonded to the adherend on the adhesive layer 1 side. Thereafter, the pressure-sensitive adhesive layer 1 of the pressure-sensitive adhesive sheet X3 is cured by radiation irradiation. As the curing radiation, the same radiation as the curing radiation described above with respect to the pressure-sensitive adhesive sheet X1 can be employed.

The pressure-sensitive adhesive sheet X3 has the pressure-sensitive adhesive layer 1 similar to the pressure-sensitive adhesive layer 1 of the pressure-sensitive adhesive sheet X1, and therefore the pressure-sensitive adhesive sheet X3 is the pressure-sensitive adhesive for the same reason as described above with respect to the pressure-sensitive adhesive sheet X1. Suitable for realizing a high modulus of elasticity with good adhesion in the layer 1. Such an adhesive sheet X3 is suitable for transmitting the external force to the adherend when an external force is applied. For example, in a state where the pressure-sensitive adhesive sheet X3 is cured after the pressure-sensitive adhesive sheet X3 is adhered to the surface of an adherend such as a touch panel, the force related to the touch operation from the pressure-sensitive adhesive sheet X3 side to the panel is applied via the pressure-sensitive adhesive sheet X3 However, it can be efficiently transmitted to the panel.

FIG. 4 shows a joined body manufacturing method according to another embodiment of the present invention. In this method, first, as shown in FIG. 4A and FIG. 4B, the member Y1 and the member Y2 are fixed or temporarily fixed via the adhesive sheet X. The pressure-sensitive adhesive sheet X is the above-mentioned pressure-sensitive adhesive sheet X1 or pressure-sensitive adhesive sheet X2 that is a double-sided pressure-sensitive adhesive sheet, and has a pressure-sensitive adhesive layer 1 that forms a pressure-sensitive adhesive surface on the surface. The member Y1 and the member Y2 are made of, for example, polycarbonate (PC), PC / ABS (polymer alloy of PC and acrylonitrile-butadiene-styrene copolymer), plastic material such as glass epoxy and glass material, or aluminum. Metal materials and glass materials. Next, the pressure-sensitive adhesive sheet X or its pressure-sensitive adhesive layer 1 is irradiated with radiation to cure the pressure-sensitive adhesive layer 1 as shown in FIG. As described above, the joined body Y including the members Y1 and Y2 can be manufactured. This method is suitable for manufacturing a bonded body Y that achieves a high elastic modulus as well as a good adhesive force in the pressure-sensitive adhesive sheet X or the pressure-sensitive adhesive layer 1 interposed between the members Y1 and Y2.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

[Preparation Example 1 of Acrylic Copolymer Solution]
In a flask (reaction vessel) equipped with a stirrer, a reflux condenser, a thermometer, a dropping device, and a nitrogen introducing tube, 37 parts by mass of 2-ethylhexyl acrylate (2EHA) and n-butyl acrylate (BA) 47. 95 parts by mass, 5 parts by mass of acrylic acid (AA), 0.05 parts by mass of 4-hydroxybutyl acrylate (4HBA), 10 parts by mass of N-vinyl-2-pyrrolidone (NVP), and acetic acid as a polymerization solvent 213 parts by mass of ethyl was charged. The introduced components were stirred for 2 hours at 23 ° C. while introducing nitrogen gas into the flask, thereby removing oxygen in the reaction system. Next, 0.2 parts by mass of 2,2′-azobisisobutyronitrile (AIBN) was added to the flask, and then the temperature was raised to 60 ° C. and a polymerization reaction was performed for 6 hours. After the reaction was stopped, 21 parts by mass of ethyl acetate was added to the flask to obtain a solution containing an acrylic copolymer (polymer solution P1). The solid content concentration of the acrylic copolymer in the polymer solution P1 was 30.0% by mass, and the weight average molecular weight of the acrylic copolymer in the polymer solution P1 was 700,000.

[Preparation Example 2 for Acrylic Copolymer Solution]
In a flask (reaction vessel) equipped with a stirrer, a reflux condenser, a thermometer, a dropping device, and a nitrogen introduction tube, 90 parts by mass of 2-ethylhexyl acrylate (2EHA), 10 parts by mass of acrylic acid (AA), 199 parts by mass of ethyl acetate as a polymerization solvent was added. The introduced components were stirred for 2 hours at 23 ° C. while introducing nitrogen gas into the flask, thereby removing oxygen in the reaction system. Next, 0.6 parts by mass of benzoyl peroxide (Nyper BW) was added to the flask, and then the temperature was raised to 60 ° C., and a polymerization reaction was performed for 6 hours. After the reaction was stopped, 137 parts by mass of toluene was added to the flask to obtain a solution containing an acrylic copolymer (polymer solution P2). The solid content concentration of the acrylic copolymer in the polymer solution P2 was 23.0% by mass, and the weight average molecular weight of the acrylic copolymer in the polymer solution P2 was 800,000.

[Preparation Example 3 of Acrylic Copolymer Solution]
In a flask (reaction vessel) equipped with a stirrer, a reflux condenser, a thermometer, a dropping device, and a nitrogen introducing tube, 37 parts by mass of 2-ethylhexyl acrylate (2EHA) and n-butyl acrylate (BA) 49. 95 parts by mass, 3 parts by mass of acrylic acid (AA), 0.05 parts by mass of 4-hydroxybutyl acrylate (4HBA), 10 parts by mass of N-vinyl-2-pyrrolidone (NVP), and acetic acid as a polymerization solvent 186 parts by mass of ethyl was charged. The introduced components were stirred for 2 hours at 23 ° C. while introducing nitrogen gas into the flask, thereby removing oxygen in the reaction system. Next, 0.2 parts by mass of 2,2′-azobisisobutyronitrile (AIBN) was added to the flask, and then the temperature was raised to 60 ° C. and a polymerization reaction was performed for 6 hours. After the reaction was stopped, 47.7 parts by mass of ethyl acetate was added to the flask to obtain a solution (polymer solution P3) containing an acrylic copolymer. The solid content concentration of the acrylic copolymer in the polymer solution P3 was 30.0% by mass, and the weight average molecular weight of the acrylic copolymer in the polymer solution P3 was 800,000.

[Acrylic copolymer solution preparation example 4]
In a flask (reaction vessel) equipped with a stirrer, a reflux condenser, a thermometer, a dropping device, and a nitrogen introducing tube, 95 parts by mass of 2-ethylhexyl acrylate (2EHA), 5 parts by mass of acrylic acid (AA), 160 parts by mass of ethyl acetate as a polymerization solvent was added. The introduced components were stirred at 23 ° C. for 2 hours while introducing nitrogen gas into the flask to remove oxygen in the reaction system. Next, 0.2 parts by mass of 2,2′-azobisisobutyronitrile (AIBN) was added to the flask, and then the temperature was raised to 60 ° C. and a polymerization reaction was performed for 6 hours. After the reaction was stopped, 53 parts by mass of ethyl acetate was added to the flask to obtain a solution containing an acrylic copolymer (polymer solution P4). The solid content concentration of the acrylic copolymer in the polymer solution P4 was 32.0% by mass, and the weight average molecular weight of the acrylic copolymer in the polymer solution P4 was 1.1 million.

[Preparation Example 5 of Acrylic Copolymer Solution]
In a flask (reaction vessel) equipped with a stirrer, a reflux condenser, a thermometer, a dropping device, and a nitrogen introduction tube, 100 parts by mass of n-butyl acrylate (BA), 3 parts by mass of acrylic acid (AA), and polymerization 191 parts by mass of ethyl acetate as a solvent was added. The introduced components were stirred at 23 ° C. for 2 hours while introducing nitrogen gas into the reaction vessel to remove oxygen in the reaction system. Next, 0.2 part by mass of 2,2′-azobisisobutyronitrile (AIBN) was added to the flask, and then the temperature was raised to 60 ° C. and a polymerization reaction was performed for 6 hours. After the reaction was stopped, 74 parts by mass of ethyl acetate was added to the flask to obtain a solution (polymer solution P5) containing an acrylic copolymer. The solid content concentration of the acrylic copolymer in the polymer solution P5 was 26.0% by mass, and the weight average molecular weight of the acrylic copolymer in the polymer solution P5 was 1,000,000.

[Example 1]
With respect to the polymer solution P1 obtained as described above, the content of the acrylic copolymer in the polymer solution P1 is 100 parts by mass, and N- (3-dimethylaminopropyl) methacrylamide (trade name “ DMAPMA ", manufactured by Evonik Japan Co., Ltd.) 7.5 parts by mass, first photopolymerization initiator (trade name" Irgacure 184 ", manufactured by BASF Japan Ltd.) 0.4 parts by mass, 0.4 parts by mass of a photopolymerization initiator (trade name “Irgacure 819”, manufactured by BASF Japan Ltd.) was added, and the mixture was sufficiently stirred so that these were dissolved. After stirring, with respect to this mixed solution, the acrylic copolymer content in the mixed solution is 100 parts by mass, and an aromatic polyisocyanate (trade name “Coronate L”, manufactured by Nippon Polyurethane Industry Co., Ltd., 1 part by weight of 75% solids) was added. And after diluting this mixed solution with ethyl acetate and adjusting solid content concentration to 30.0%, the said mixed solution is fully stirred and a solvent-type and radiation-curing-type adhesive composition (adhesive composition) Product 1) was obtained. Next, the pressure-sensitive adhesive layer that is formed after drying the pressure-sensitive adhesive composition 1 on the silicone-treated surface of a 38 μm polyethylene terephthalate separator (trade name “MRF38”, manufactured by Mitsubishi Polyester Film Co., Ltd.) The thickness of the coating was 49 μm. Next, the pressure-sensitive adhesive composition 1 applied on the separator was subjected to heat drying at 100 ° C. for 2 minutes to form a pressure-sensitive adhesive layer. Next, a 38 μm polyethylene terephthalate separator (trade name “MRE38”, manufactured by Mitsubishi Polyester Film Co., Ltd.) is applied to the pressure-sensitive adhesive layer, and the silicone-treated surface of the separator and the surface of the pressure-sensitive adhesive layer (adhesive surface). It was pasted in such a manner that it touches. As described above, the pressure-sensitive adhesive sheet of Example 1 (substrate-less double-sided pressure-sensitive adhesive sheet having a laminated structure of separator / adhesive layer / separator) was produced. The raw materials for producing the pressure-sensitive adhesive sheet of Example 1 are summarized in Table 1 described later. The same applies to Examples 2 to 9 below.

[Example 2]
A pressure-sensitive adhesive sheet of Example 2 was prepared in the same manner as Example 1 except that the addition amount of N- (3-dimethylaminopropyl) methacrylamide as a basic monomer was changed to 10 parts by mass instead of 7.5 parts by mass. did.

Example 3
With respect to the polymer solution P2 obtained as described above, the content of the acrylic copolymer in the polymer solution P2 is 100 parts by mass, and N- (3-dimethylaminopropyl) acrylamide (DMAPAA, Wako Pure) as a basic monomer is used. Yaku Kogyo Co., Ltd.) 5.0 parts by mass, first photopolymerization initiator (trade name “Irgacure 184”, manufactured by BASF Japan Ltd.) 0.4 parts by mass, and second photopolymerization initiator (trade name) 0.4 parts by mass of “Irgacure 819” (manufactured by BASF Japan Ltd.) was added, and the mixture was sufficiently stirred to dissolve. And after diluting this mixed solution with ethyl acetate and adjusting solid content concentration to 30.0%, the said mixed solution is fully stirred and a solvent-type and radiation-curing-type adhesive composition (adhesive composition) Product 2) was obtained. Using this pressure-sensitive adhesive composition 2, a pressure-sensitive adhesive sheet of Example 3 (base material-less double-sided pressure-sensitive adhesive sheet having a laminated structure of separator / pressure-sensitive adhesive layer / separator) was produced. The production method of the pressure-sensitive adhesive sheet of Example 3 is the same as the production method of the pressure-sensitive adhesive sheet of Example 1, except that the pressure-sensitive adhesive composition 2 is used instead of the pressure-sensitive adhesive composition 1.

Example 4
The addition amount of N- (3-dimethylaminopropyl) acrylamide as a basic monomer was changed to 2.5 parts by mass instead of 5.0 parts by mass, and the pressure-sensitive adhesive composition 2 was further added as a polyfunctional acrylic oligomer. Except for containing 10 parts by mass of functional urethane acrylate (trade name “purple light UV-7650B”, manufactured by Nippon Synthetic Chemical Co., Ltd., weight average molecular weight 2300, number of functional groups 4-5, solid content 99%), the same as in Example 3 Thus, a pressure-sensitive adhesive sheet of Example 4 was produced.

Example 5
The addition amount of N- (3-dimethylaminopropyl) methacrylamide as a basic monomer was changed to 2.5 parts by mass instead of 7.5 parts by mass, and the pressure-sensitive adhesive composition 1 was further a polyfunctional acrylic oligomer. A pressure-sensitive adhesive sheet of Example 5 was produced in the same manner as in Example 1 except that 10 parts by mass of a polyfunctional urethane acrylate (trade name “purple light UV-7650B”, manufactured by Nippon Synthetic Chemical Co., Ltd.) was included.

Example 6
The addition amount of N- (3-dimethylaminopropyl) methacrylamide as a basic monomer was changed to 2.5 parts by mass instead of 7.5 parts by mass, and the pressure-sensitive adhesive composition 1 was further a polyfunctional acrylic oligomer. A pressure-sensitive adhesive sheet of Example 6 was produced in the same manner as Example 1 except that it contained 10 parts by mass of polyfunctional urethane acrylate (trade name “UA-510H”, manufactured by Kyoeisha Chemical Co., Ltd., 10 functional groups).

Example 7
The addition amount of N- (3-dimethylaminopropyl) methacrylamide as a basic monomer was changed to 2.5 parts by mass instead of 7.5 parts by mass, and the pressure-sensitive adhesive composition 1 was further a polyfunctional acrylic oligomer. A pressure-sensitive adhesive sheet of Example 7 was produced in the same manner as Example 1 except that it contained 10 parts by mass of a polyfunctional urethane acrylate (trade name “UA-306H”, manufactured by Kyoeisha Chemical Co., Ltd., 6 functional groups).

Example 8
The addition amount of N- (3-dimethylaminopropyl) methacrylamide as a basic monomer was changed to 2.5 parts by mass instead of 7.5 parts by mass, and the pressure-sensitive adhesive composition 1 was further a polyfunctional acrylic oligomer. A pressure-sensitive adhesive sheet of Example 8 was produced in the same manner as in Example 1 except that it contained 10 parts by mass of a polyfunctional urethane acrylate (trade name “UA-306I”, manufactured by Kyoeisha Chemical Co., Ltd., 6 functional groups).

Example 9
Implemented in the same manner as in Example 1, except that the pressure-sensitive adhesive composition 1 further contains 10 parts by mass of a polyfunctional urethane acrylate (trade name “purple UV-7650B”, manufactured by Nippon Synthetic Chemical Co., Ltd.), which is a polyfunctional acrylic oligomer. The adhesive sheet of Example 9 was produced.

Example 10
With respect to the polymer solution P3 obtained as described above, the content of the acrylic copolymer in the polymer solution P3 is 100 parts by mass, and the basic monomer N- (3-dimethylaminopropyl) methacrylamide (trade name “ DMAPMA ”(manufactured by Evonik Japan Co., Ltd.) 2.5 parts by mass, polyfunctional urethane acrylate (trade name“ purple light UV-7650B ”, manufactured by Nippon Synthetic Chemical Co., Ltd.) as a polyfunctional acrylic oligomer, 10 parts by mass, Photopolymerization initiator (trade name “Irgacure 184”, manufactured by BASF Japan Ltd.) 0.4 mass part and second photopolymerization initiator (trade name “Irgacure 819”, produced by BASF Japan Ltd.) 0.4 mass And stirred sufficiently to dissolve them. After stirring, with respect to this mixed solution, an aromatic polyisocyanate serving as a crosslinking agent (trade name “Coronate L”, manufactured by Nippon Polyurethane Industry Co., Ltd.) with the acrylic copolymer content in the mixed solution as 100 parts by mass. 1 part by weight was added. And after diluting this mixed solution with ethyl acetate and adjusting solid content concentration to 30.0%, the said mixed solution is fully stirred and a solvent-type and radiation-curing-type adhesive composition (adhesive composition) Product 3) was obtained. Using this pressure-sensitive adhesive composition 3, a pressure-sensitive adhesive sheet of Example 10 (baseless double-sided pressure-sensitive adhesive sheet having a laminated structure of separator / pressure-sensitive adhesive layer / separator) was produced. The method for producing the pressure-sensitive adhesive sheet of Example 10 is the same as the method for producing the pressure-sensitive adhesive sheet of Example 1, except that the pressure-sensitive adhesive composition 3 is used in place of the pressure-sensitive adhesive composition 1. The raw materials for producing the pressure-sensitive adhesive sheet of Example 10 are summarized in Table 2 below. The same applies to Examples 11 to 17 below.

Example 11
The pressure-sensitive adhesive sheet of Example 11 was the same as Example 10 except that the basic monomer N- (3-dimethylaminopropyl) methacrylamide was added in an amount of 7.5 parts by mass instead of 2.5 parts by mass. Was made.

Example 12
With respect to the polymer solution P4 obtained as described above, the content of the acrylic copolymer in the polymer solution P4 is 100 parts by mass, and N- (3-dimethylaminopropyl) methacrylamide (trade name “ DMAPMA ”(manufactured by Evonik Japan) 4.0 parts by mass, polyfunctional urethane acrylate (trade name“ purple UV-7650B ”, manufactured by Nippon Synthetic Chemical Co., Ltd.) as a polyfunctional acrylic oligomer, Photopolymerization initiator (trade name “Irgacure 184”, manufactured by BASF Japan Ltd.) 0.4 mass part and second photopolymerization initiator (trade name “Irgacure 819”, produced by BASF Japan Ltd.) 0.4 mass And stirred sufficiently to dissolve them. After stirring, with respect to this mixed solution, an aromatic polyisocyanate serving as a crosslinking agent (trade name “Coronate L”, manufactured by Nippon Polyurethane Industry Co., Ltd.) with the acrylic copolymer content in the mixed solution as 100 parts by mass. 1 part by weight was added. And after diluting this mixed solution with ethyl acetate and adjusting solid content concentration to 30.0%, the said mixed solution is fully stirred and a solvent-type and radiation-curing-type adhesive composition (adhesive composition) Product 4) was obtained. Using this pressure-sensitive adhesive composition 4, a pressure-sensitive adhesive sheet of Example 12 (baseless-less double-sided pressure-sensitive adhesive sheet having a laminated structure of separator / pressure-sensitive adhesive layer / separator) was produced. The method for producing the pressure-sensitive adhesive sheet of Example 12 is the same as the method for producing the pressure-sensitive adhesive sheet of Example 1, except that the pressure-sensitive adhesive composition 4 is used instead of the pressure-sensitive adhesive composition 1.

Example 13
The addition amount of N- (3-dimethylaminopropyl) methacrylamide as a basic monomer was changed to 10 parts by mass instead of 4.0 parts by mass, and the addition amount of the first photopolymerization initiator was 0.4 parts by mass. The pressure-sensitive adhesive sheet of Example 13 was the same as Example 12 except that the content was 0.2 parts by mass, the second photopolymerization initiator was not used, and the crosslinking agent was not used. Was made.

Example 14
With respect to the polymer solution P5 obtained as described above, the content of the acrylic copolymer in the polymer solution P5 is 100 parts by mass, and the basic monomer N- (3-dimethylaminopropyl) methacrylamide (trade name “ DMAPMA ”(manufactured by Evonik Japan Co., Ltd.) 10 parts by mass, polyfunctional urethane acrylate (trade name“ purple light UV-7650B ”, produced by Nippon Synthetic Chemical Co., Ltd.) as a polyfunctional acrylic oligomer, and first photopolymerization 0.4 parts by mass of an initiator (trade name “Irgacure 184”, manufactured by BASF Japan Ltd.) and 0.4 parts by mass of a second photopolymerization initiator (trade name “Irgacure 819”, produced by BASF Japan Ltd.) And stirred well to dissolve them. After stirring, with respect to this mixed solution, an aromatic polyisocyanate serving as a crosslinking agent (trade name “Coronate L”, manufactured by Nippon Polyurethane Industry Co., Ltd.) with the acrylic copolymer content in the mixed solution as 100 parts by mass. 2 parts by weight were added. And after diluting this mixed solution with ethyl acetate and adjusting solid content concentration to 30.0%, the said mixed solution is fully stirred and a solvent-type and radiation-curing-type adhesive composition (adhesive composition) Product 5) was obtained. Using this pressure-sensitive adhesive composition 5, a pressure-sensitive adhesive sheet of Example 14 (base material-less double-sided pressure-sensitive adhesive sheet having a laminated structure of separator / pressure-sensitive adhesive layer / separator) was produced. The production method of the pressure-sensitive adhesive sheet of Example 14 is the same as the production method of the pressure-sensitive adhesive sheet of Example 1, except that the pressure-sensitive adhesive composition 5 is used instead of the pressure-sensitive adhesive composition 1.

Example 15
A pressure-sensitive adhesive sheet of Example 15 was produced in the same manner as Example 14 except that the addition amount of N- (3-dimethylaminopropyl) methacrylamide as a basic monomer was changed to 15 parts by mass instead of 10 parts by mass.

Example 16
Instead of 5.0 parts by mass of N- (3-dimethylaminopropyl) acrylamide as a basic monomer, N- (3-dimethylaminopropyl) methacrylamide (trade name “DMAPMA”, manufactured by Evonik Japan) 2.5 masses 1 part of addition, 10 parts by weight of the polyfunctional urethane acrylate (trade name “purple light UV-7650B”, manufactured by Nippon Synthetic Chemical Co., Ltd.) which is a polyfunctional acrylic oligomer. In the same manner as in Example 3, except that the addition amount of the polymerization initiator was changed to 0.2 parts by mass instead of 0.4 parts by mass, and that the second photopolymerization initiator was not used. Sixteen pressure-sensitive adhesive sheets were produced.

Example 17
Adhesive composition 2 having 5.0 parts by mass of dimethylaminoethyl methacrylate (DMAEMA, manufactured by Tokyo Chemical Industry Co., Ltd.) instead of 5.0 parts by mass of N- (3-dimethylaminopropyl) acrylamide as a basic monomer Further contains 10 parts by mass of a polyfunctional urethane acrylate (trade name “purple light UV-7650B”, manufactured by Nippon Synthetic Chemical Co., Ltd.), which is a polyfunctional acrylic oligomer, and the added amount of the first photopolymerization initiator is 0.4 mass. 0.2 parts by mass instead of the part, the second photopolymerization initiator was not used, and the aromatic polyisocyanate (trade name “Coronate L”, A pressure-sensitive adhesive sheet of Example 17 was produced in the same manner as Example 3 except that 1 part by mass of Nippon Polyurethane Industry Co., Ltd. was included.

[Comparative Example 1]
N- (3-dimethylaminopropyl) methacrylamide as a basic monomer is not used, and polyfunctional urethane acrylate (trade name “purple light UV-7650B”, manufactured by Nippon Synthetic Chemical Co., Ltd.) is used in place of 10 parts by mass. A pressure-sensitive adhesive sheet of Comparative Example 1 was produced in the same manner as in Example 12 except that a functional acrylic oligomer (trade name “Aronix M-6100”, manufactured by Toa Gosei Co., Ltd., functional group number 2) was used. The raw materials for producing the pressure-sensitive adhesive sheet of Comparative Example 1 are summarized in Table 3 below. The same applies to Comparative Examples 2 to 9 below.

[Comparative Example 2]
Do not use N- (3-dimethylaminopropyl) methacrylamide as a basic monomer, and add 10 parts by mass of polyfunctional urethane acrylate (trade name “purple light UV-7650B”, manufactured by Nippon Synthetic Chemical Co., Ltd.) A pressure-sensitive adhesive sheet of Comparative Example 2 was produced in the same manner as in Example 12 except that the content was changed to 15 parts by mass.

[Comparative Example 3]
Do not use N- (3-dimethylaminopropyl) methacrylamide as a basic monomer, and add 5 parts by mass of polyfunctional urethane acrylate (trade name “purple light UV-7650B”, manufactured by Nippon Synthetic Chemical Co., Ltd.) A pressure-sensitive adhesive sheet of Comparative Example 3 was produced in the same manner as in Example 14 except that the content was changed to 15 parts by mass.

[Comparative Example 4]
N- (3-dimethylaminopropyl) methacrylamide as a basic monomer is not used, and polyfunctional urethane acrylate (trade name “purple light UV-7650B”, manufactured by Nippon Synthetic Chemical Co., Ltd.) is used in place of 5 parts by mass. A pressure-sensitive adhesive sheet of Comparative Example 4 in the same manner as in Example 14 except that 15 parts by mass of a functional acrylic oligomer (trade name “UA-1100H”, manufactured by Shin-Nakamura Chemical Co., Ltd., weight average molecular weight 760, functional group number 6) was used. Was made.

[Comparative Example 5]
N- (3-dimethylaminopropyl) methacrylamide as a basic monomer is not used, and polyfunctional urethane acrylate (trade name “purple light UV-7650B”, manufactured by Nippon Synthetic Chemical Co., Ltd.) is used in place of 5 parts by mass. A pressure-sensitive adhesive sheet of Comparative Example 5 was produced in the same manner as in Example 14 except that 15 parts by mass of functional urethane acrylate (trade name “UA-510H”) was used.

[Comparative Example 6]
N- (3-dimethylaminopropyl) methacrylamide as a basic monomer is not used, and polyfunctional urethane acrylate (trade name “purple light UV-7650B”, manufactured by Nippon Synthetic Chemical Co., Ltd.) is used in place of 5 parts by mass. A pressure-sensitive adhesive sheet of Comparative Example 6 was produced in the same manner as Example 14 except that 15 parts by mass of functional urethane acrylate (trade name “UA-306H”) was used.

[Comparative Example 7]
Do not use N- (3-dimethylaminopropyl) methacrylamide as a basic monomer, do not use polyfunctional urethane acrylate (trade name “purple light UV-7650B”, manufactured by Nippon Synthetic Chemical Co., Ltd.), and adhesive A pressure-sensitive adhesive sheet of Comparative Example 7 was produced in the same manner as in Example 12 except that Composition 4 further contained 10 parts by mass of N-vinyl-2-pyrrolidone (NVP, manufactured by Nippon Shokubai Co., Ltd.) as a nitrogen-containing monomer.

[Comparative Example 8]
Do not use N- (3-dimethylaminopropyl) methacrylamide as a basic monomer, do not use polyfunctional urethane acrylate (trade name “purple light UV-7650B”, manufactured by Nippon Synthetic Chemical Co., Ltd.), and adhesive A pressure-sensitive adhesive sheet of Comparative Example 8 was produced in the same manner as in Example 12 except that the composition 4 further contained 10 parts by mass of diacetone acrylamide (DAAM, manufactured by Nihon Gosei Co., Ltd.) as a nitrogen-containing monomer.

[Comparative Example 9]
Do not use N- (3-dimethylaminopropyl) methacrylamide as a basic monomer, do not use polyfunctional urethane acrylate (trade name “purple light UV-7650B”, manufactured by Nippon Synthetic Chemical Co., Ltd.), and adhesive A pressure-sensitive adhesive sheet of Comparative Example 9 was produced in the same manner as in Example 12 except that the composition 4 further contained 10 parts by mass of dimethylacrylamide (DMAA, manufactured by Kojin Film & Chemicals) as a nitrogen-containing monomer.

[Measurement and evaluation]
The following measurements and evaluations were performed on the pressure-sensitive adhesive sheets of Examples 1 to 17 and the pressure-sensitive adhesive sheets of Comparative Examples 1 to 9. When performing measurement and evaluation, the target adhesive sheet was previously left at 50 ° C. for 24 hours in a light-shielding sheet that was not exposed to light. The measurement results and evaluation are listed in Tables 1 to 3.

<Weight average molecular weight>
The weight average molecular weight of the obtained acrylic copolymer was measured by GPC (gel permeation chromatography) according to the specifications listed below. As a sample solution to be measured, an acrylic copolymer sample is dissolved in tetrahydrofuran to obtain a 0.1% by mass solution, which is allowed to stand overnight, and then filtered through a 0.45 μm membrane filter. It was.
・ Analyzer: HLC-8120GPC (manufactured by Tosoh Corporation)
Column: TSKgel GMH _HR- H (S) (manufactured by Tosoh Corporation)
-Column size: 7.8 mmφ x 30 cm
・ Eluent: Tetrahydrofuran (concentration 0.1% by mass)
・ Flow rate: 0.5ml / min
・ Detector: Differential refractometer (RI)
-Column temperature: 40 ° C
・ Injection volume: 100 μl
Standard sample: polystyrene

<PH of monomer aqueous solution>
For the monomers listed below, 10 ml of an aqueous monomer solution (prepared by dissolving 0.6 g of monomer in 30 ml of ion exchange water) is weighed into a beaker, 40 ml of ion exchange water is added, and the pH meter is stirred with a magnetic stirrer. Was immersed in the solution, and the pH was measured. The results are as follows.
DMAPMA 10.05
・ DMAPAA 10.35
DMAEMA 8.79
・ NVP 5.96
・ DAAM 6.02
DMAA 6.22

<Gel fraction>
About 0.1 g (mass: W ₁ mg) of an adhesive sample is taken from the adhesive layer of the adhesive sheet, and is drawn in a tetrafluoroethylene resin porous membrane (mass: W ₂ mg) with an average pore diameter of 0.2 μm. The mouth was tied with silk thread (mass: W ₃ mg) to obtain a wrap. This packet was put into a screw tube with a capacity of 50 mL, and the screw tube was filled with ethyl acetate (one screw tube was used for each packet). This was allowed to stand at room temperature (typically 23 ° C.) for 7 days, and then the packet was taken out of the screw tube and dried at 130 ° C. for 2 hours. Thereafter, the mass (W ₄ mg) of the packet was measured. Then, the gel fraction of the pressure-sensitive adhesive layer was calculated by substituting the values of W ₁ to W ₄ into the following formula.

Gel fraction [%] = [(W ₄ −W ₂ −W ₃ ) / W ₁ ] × 100

As the porous membrane made of tetrafluoroethylene resin, a porous membrane made of tetrafluoroethylene resin (trade name “Nitoflon (registered trademark) NTF1122”) manufactured by Nitto Denko Corporation was used. For each example and each comparative example, the gel fraction before UV irradiation using a sample that has not yet been irradiated with ultraviolet rays to the adhesive sheet, and the adhesive layer was cured by already irradiating the adhesive sheet with ultraviolet rays The gel fraction after UV irradiation using the sample after being allowed to obtain was determined. Moreover, ultraviolet irradiation was performed with respect to the adhesive sheet which was pinched | interposed into the ultraviolet-ray-permeable separator (MRE38), using the metal halide lamp (Toshiba make, M3000L / 22) as a light source. The illuminance of ultraviolet rays was 300 mW / cm ² and the cumulative irradiation amount was 3000 mJ / cm ² . The pressure-sensitive adhesive sample to be subjected to such gel fraction measurement was covered with a light-shielding sheet so as not to be exposed to light until measurement.

<Young's modulus (before UV irradiation)>
A cylindrical measurement sample having a diameter of 3 mm and a length of 30 mm was produced by winding the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet before ultraviolet irradiation into a columnar shape. Next, in a measurement environment at a temperature of 23 ° C. and a relative humidity of 50%, using a tensile tester, the length between the chucks (corresponding to the initial length for measurement) is 10 mm in the tester. The sample was set in a testing machine, and the measurement sample was pulled under conditions of a tensile speed of 50 mm / min. And Young's modulus was computed from the result of the obtained displacement and stress. The measurement sample to be subjected to such measurement was covered and stored with a light shielding sheet so as not to be exposed to light until the measurement.

<Young's modulus (after UV irradiation)>
Using a metal halide lamp (manufactured by Toshiba Corporation, M3000L / 22) with the separator (MRE38) attached to the pressure-sensitive adhesive sheet (base material-less double-sided pressure-sensitive adhesive sheet having a laminated structure of separator / adhesive layer / separator), The pressure-sensitive adhesive layer was cured by irradiating with ultraviolet rays at an illuminance of 300 mW / cm ² and an integrated dose of 3000 mJ / cm ² . Next, a cylindrical measurement sample having a diameter of 3 mm and a length of 30 mm was produced by winding the cured pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet after irradiation with ultraviolet rays into a cylindrical shape. Next, using a tensile tester in a measurement environment at a temperature of 23 ° C. and a relative humidity of 50%, the measurement sample is set in the test machine so that the chuck spacing is 10 mm in the tester, and the measurement sample is pulled at a tensile speed of 50 mm. Pulled under conditions of / min. And Young's modulus was computed from the result of the obtained displacement and stress. The measurement sample to be subjected to such measurement was covered and stored with a light shielding sheet so as not to be exposed to light until the measurement.

<Adhesive strength (before UV irradiation)>
After the separator on one side of the pressure-sensitive adhesive sheet was peeled off, the pressure-sensitive adhesive sheet was affixed to a polyethylene terephthalate (PET) film having a thickness of 50 μm on the exposed pressure-sensitive adhesive surface. A test piece (width 20 mm × length 100 mm) was cut out from the backed adhesive sheet. The separator on the other side was peeled off from the test piece, the test piece was bonded to the adherend, and the test piece and the adherend were pressure bonded by reciprocating a 2 kg roller once. Thereafter, it was stored for 24 hours. After storage, a test piece was peeled from the adherend using a tensile tester under the conditions of a tensile speed of 300 mm / min and a tensile angle of 180 °, and the peel strength (N / 20 mm) was measured. The peel strength was defined as the adhesive strength before UV irradiation. Preparation of the test piece, storage of the test piece, and measurement of the peel strength were performed in an environment at a temperature of 23 ° C. and a relative humidity of 50%. The test piece was produced and stored in a state where it was covered with a light-shielding sheet so as not to be exposed to light. The adhesive strength measurement as described above is performed for each example and each comparative example, both when the stainless steel plate (SUS304) is used as the adherend and when the PC plate (polycarbonate resin plate) is used as the adherend. It was.

<Adhesive strength (after UV irradiation)>
After the separator on one side of the pressure-sensitive adhesive sheet was peeled off, the pressure-sensitive adhesive sheet was affixed to a polyethylene terephthalate (PET) film having a thickness of 50 μm on the exposed pressure-sensitive adhesive surface. A test piece (width 20 mm × length 100 mm) was cut out from the backed adhesive sheet. The separator on the other side was peeled off from the test piece, the test piece was bonded to the adherend, and the test piece and the adherend were pressure bonded by reciprocating a 2 kg roller once. Thereafter, it was stored for 12 hours. After storage, the test piece was irradiated with ultraviolet rays from the PET film side to cure the adhesive layer of the test piece. For the ultraviolet irradiation, a metal halide lamp (M3000L / 22, manufactured by Toshiba Corporation) was used, the illuminance of the ultraviolet light was 300 mW / cm ² , and the integrated irradiation amount was 3000 mJ / cm ² . After such ultraviolet irradiation, the test piece was further stored for 12 hours. After storage, a test piece was peeled from the adherend using a tensile tester under the conditions of a tensile speed of 300 mm / min and a tensile angle of 180 °, and the peel strength (N / 20 mm) was measured. The peel strength was defined as the adhesive strength after UV irradiation. Preparation of the test piece, storage of the test piece, irradiation of ultraviolet rays, and measurement of peel strength were performed in an environment at a temperature of 23 ° C. and a relative humidity of 50%. The test piece was produced and stored in a state where it was covered with a light-shielding sheet so as not to be exposed to light. The adhesive strength measurement as described above is performed for each example and each comparative example, both when the stainless steel plate (SUS304) is used as the adherend and when the PC plate (polycarbonate resin plate) is used as the adherend. It was.

[Evaluation]
The pressure-sensitive adhesive sheets of Examples 1 to 17 are formed of a pressure-sensitive adhesive layer by an acrylic pressure-sensitive adhesive layer containing an acrylic copolymer containing a carboxyl group-containing monomer as a constituent element at a predetermined abundance, a basic monomer, and a photopolymerization initiator. Is configured. As shown in Tables 1 and 2, each of the pressure-sensitive adhesive sheets of Examples 1 to 17 has an adhesive strength after UV irradiation exceeding 9.0 N / 20 mm and a Young's modulus after UV irradiation of 300 kPa. Exceed. On the other hand, as shown in Table 3, the pressure-sensitive adhesive sheets of Comparative Examples 1 to 9 that do not have the configuration of the present invention have an adhesive strength after UV irradiation of more than 9.0 N / 20 mm and a Young's modulus after UV irradiation. There is nothing exceeding 300 kPa. The pressure-sensitive adhesive sheets of Comparative Examples 1, 2, 7 to 9 having relatively high UV-irradiation adhesive strength have insufficient Young's modulus after UV irradiation. The adhesive sheets of Comparative Examples 3 to 6 having a relatively high Young's modulus after UV irradiation have insufficient adhesive strength after UV irradiation. From the above, it can be understood that in the pressure-sensitive adhesive sheets of Examples 1 to 17, a high Young's modulus or elastic modulus is realized with a good adhesive force in the pressure-sensitive adhesive layer after curing.

X1, X2, X3, X Adhesive sheet 1 Adhesive layer 2 Base material Y Assembly

Claims

It has an acrylic pressure-sensitive adhesive layer that contains an acrylic copolymer, a basic monomer, and a photopolymerization initiator and can be cured by radiation irradiation.
The pressure-sensitive adhesive sheet, wherein the acrylic copolymer includes a monomer unit derived from a carboxyl group-containing monomer having a content of 0.5 to 10% by mass in a raw material monomer component for forming the acrylic copolymer.
The pressure-sensitive adhesive sheet according to claim 1, wherein the acrylic copolymer includes a monomer unit derived from a hydroxyl group-containing monomer.
The pressure-sensitive adhesive according to claim 1, wherein the acrylic copolymer includes a monomer unit derived from a hydroxyl group-containing monomer having a content of 0.01 to 5% by mass in a raw material monomer component for forming the acrylic copolymer. Sheet.
The pressure-sensitive adhesive sheet according to any one of claims 1 to 3, wherein the acrylic copolymer includes a monomer unit derived from a nitrogen atom-containing monomer.
The acrylic copolymer includes a monomer unit derived from a nitrogen atom-containing monomer having a content of 0.5 to 30% by mass in a raw material monomer component for forming the acrylic copolymer. The pressure-sensitive adhesive sheet according to any one of the above.
6. The pressure-sensitive adhesive sheet according to claim 1, wherein the nitrogen atom-containing monomer contains an N-vinyl cyclic amide and / or (meth) acrylamide represented by the following formula (1).

[In Formula (1), R 1 represents a divalent organic group]
The nitrogen atom-containing monomer is selected from the group consisting of N-vinyl-2-pyrrolidone, N-vinyl-2-caprolactam, N, N-dimethyl (meth) acrylamide, and N, N-diethyl (meth) acrylamide. The pressure-sensitive adhesive sheet according to any one of claims 1 to 5, comprising at least one kind.
The pressure-sensitive adhesive sheet according to any one of claims 1 to 7, wherein the basic monomer has an acid dissociation constant pKa of 8.0 or more having an amide group and / or an amino group in the molecule.
In the acrylic pressure-sensitive adhesive layer, the content of the basic monomer is 0.1 to 20 parts by mass with respect to 100 parts by mass of the acrylic copolymer, and the content of the photopolymerization initiator is the acrylic copolymer. The pressure-sensitive adhesive sheet according to any one of claims 1 to 8, which is 0.05 to 5 parts by mass with respect to 100 parts by mass of the combined body.
The mass ratio of the basic monomer to the carboxyl group-containing monomer contained in the raw material monomer component for forming the acrylic copolymer in the acrylic pressure-sensitive adhesive layer is 0.01 to 40. The pressure-sensitive adhesive sheet according to any one of 1 to 8.
The said basic monomer contains at least 1 type selected from the compound group represented by following formula (2), and the compound group represented by following formula (3), It is any one of Claim 1 to 10 characterized by the above-mentioned. Adhesive sheet.

[In the formula (2), R 2 represents a hydrogen atom or a methyl group, R 3 represents a linear or branched alkylene group having 2 to 6 carbon atoms, and R 4 and R 5 are each hydrogen. Represents an atom or a linear or branched alkyl group having 1 to 4 carbon atoms]

[In the formula (3), R 6 represents a hydrogen atom or a methyl group, R 7 represents a linear or branched alkylene group having 2 to 6 carbon atoms, and R 8 and R 9 are each hydrogen. Represents an atom or a linear or branched alkyl group having 1 to 4 carbon atoms]
The basic monomer includes at least one selected from the group consisting of N- (3-dimethylaminopropyl) methacrylamide, N- (3-dimethylaminopropyl) acrylamide, and 2-dimethylaminoethyl methacrylate. The pressure-sensitive adhesive sheet according to any one of 1 to 10.
The pressure-sensitive adhesive sheet according to any one of claims 1 to 12, wherein the basic monomer has a boiling point of 120 ° C or higher.
The pressure-sensitive adhesive sheet according to any one of claims 1 to 13, wherein the acrylic pressure-sensitive adhesive layer further contains a polyfunctional acrylic oligomer.
The pressure-sensitive adhesive sheet according to claim 14, wherein the polyfunctional acrylic oligomer has three or more (meth) acryloyl groups in the molecule.
The pressure-sensitive adhesive sheet according to claim 14 or 15, wherein the polyfunctional acrylic oligomer has a weight average molecular weight of 500 to 30,000.
The pressure-sensitive adhesive sheet according to any one of claims 1 to 16, wherein the acrylic copolymer has a weight average molecular weight of 400,000 to 2 million.
After the second member is temporarily fixed to the first member via the pressure-sensitive adhesive sheet according to any one of claims 1 to 17, the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet is irradiated with radiation and the pressure-sensitive adhesive A method for producing a joined body, wherein the agent layer is cured.