TW201920536A - Adhesive composition and adhesive sheet - Google Patents

Abstract

An adhesive composition which comprises: a copolymer (A) which includes 1 to 5 mol% of a structural component originated from a monomer (a-1), which has an SP value of 9.50 (cal/cm3)<SP>0.5</SP> or more, and 95 to 99 mol% of a structural component originated from a monomer (a-2), which has an SP value of less than 9.50 (cal/cm3)<SP>0.5</SP>; (B) represented by the general formula (1); and an ionic liquid (E). (In the general formula (1), R1 represents a hydroxyl group or a methyl group, R2 represents a hydroxyl group or a group which has ethylenically unsaturated bond, R3 represents a hydroxyl group or a group which has ethylenically unsaturated bond, X represents a group which has a cyclic structure, and n represents a positive integer.).

Description

Adhesive composition and adhesive sheet

The present invention relates to an adhesive composition and an adhesive sheet.案 This case claims priority based on Japanese Patent Application No. 2017-135534 filed in Japan on July 11, 2017, and incorporates its contents here.

When manufacturing parts such as electrical parts, electronic parts, and semiconductor parts, cutting is performed. In the dicing process, a wafer on which a plurality of parts are formed is cut and diced into individual parts, which are used as component chips (wafers). In the past, wafer processing such as dicing was performed in a state where an adhesive sheet such as an adhesive tape was attached to the wafer. By attaching an adhesive sheet to the wafer, the parts set on the wafer to be processed are fixed, and the surface of the wafer to be processed is also protected. The adhesive tape attached to the wafer is peeled off and removed after the wafer processing is completed.

In recent years, as an adhesive sheet to be attached to a wafer during wafer processing, an adhesive layer having a resin composition containing UV (ultraviolet) curing is used. When such an adhesive sheet is attached to a wafer and irradiated with ultraviolet rays, the resin composition in the adhesive layer is crosslinked, and the adhesive force is reduced. Therefore, when the adhesive sheet is peeled from the wafer, it can be peeled with a small force.

When the wafer (adhesive body) to which the adhesive sheet is attached is an insulating material, when the adhesive sheet is peeled from the wafer, static electricity called peeling and charging is generated between the adhesive body and the adhesive sheet. The peeling and electrification may cause electrostatic interference such as damage to the circuit provided on the adherend. Therefore, in the case where the adherend is an insulating material, a person having antistatic properties capable of suppressing peeling and charging is used as the adhesive sheet.

As the antistatic adhesive sheet, there are an adhesive sheet provided with an adhesive layer on a substrate sheet to which antistatic treatment has been applied, an adhesive sheet provided with an antistatic layer between the substrate sheet and the adhesive layer, and Adhesive sheet of the adhesive layer of the antistatic agent. Patent Document 1 describes an adhesive composition containing an ionic liquid, and describes an antistatic surface protective film having an adhesive layer containing the adhesive composition. [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent No. 3912686

[Questions to be Solved by the Invention]

However, in the conventional adhesive sheet, peeling and charging may not be sufficiently suppressed. Therefore, there is a demand for an adhesive sheet that can more effectively suppress peeling and charging. The present invention has been made in view of the foregoing facts, and an object of the present invention is to provide an adhesive composition capable of forming an adhesive layer having sufficiently high adhesive force before UV irradiation, and low adhesive force and low surface resistance after UV irradiation. Thing.课题 The object of the present invention is to provide an adhesive layer having a sufficiently high adhesive force before UV irradiation and a low adhesive force and low surface resistance value after UV irradiation, and can effectively suppress peeling and charging of an adhesive sheet. [Means to solve the problem]

In order to solve the above-mentioned problems, the inventor of the present case has conducted intensive studies repeatedly. As a result, it was found that if a (meth) acrylic resin containing a copolymer containing a specific component derived from a (meth) acrylic monomer in a specific ratio is used, a specific polyfunctional epoxy (meth) acrylate is used. The hardener, the photopolymerization initiator, and the adhesive composition of the ionic liquid may be used, and the present invention is considered. That is, the present invention relates to the following matters.

[1] An adhesive composition comprising a (meth) acrylic resin (A), a polyfunctional epoxy (meth) acrylate (B), a hardener (C), and photopolymerization. Initiator (D) and ionic liquid (E), the (meth) acrylic resin (A) contains a (meth) acrylic monomer (a) derived from an SP value of 9.50 (cal / cm ³ ) ^0.5 or more -1) constituents 1 to 5 mole% and constituents 95 to 99 moles containing (meth) acrylic monomer (a-2) derived from SP value less than 9.50 (cal / cm ³ ) ^0.5 In the case of an ear-% copolymer, the aforementioned polyfunctional epoxy (meth) acrylate (B) is a compound represented by the following formula (1).

(In formula (1), R ¹ is a hydrogen atom or a methyl group, which may be the same or different, respectively; R ² is a hydrogen atom or a group having an ethylenically unsaturated bond; R ³ is a hydrogen atom or a group having an ethylenically unsaturated bond R ³ has at least one ethylenically unsaturated bond when n is 1 and R ² is a hydrogen atom; when R ³ is n or more and R ² is a hydrogen atom, plural R ³ A part or all of R ³ has at least one ethylenically unsaturated bond; X is a base having a ring structure; n is a positive integer).

[2] The adhesive composition according to [1], wherein X in the formula (1) is a base represented by the formula (2).

(In formula (2), R ⁴ is a hydrogen atom or a methyl group, and may be the same or different, respectively).

[3] The adhesive composition according to [1], wherein X in the formula (1) is a base represented by the formula (3).

(In formula (3), R ⁵ is a hydrogen atom or a methyl group, and may be the same or different, respectively).

[4] The adhesive composition according to any one of [1] to [3], wherein the ionic liquid (E) comprises: 1-ethyl-3-methylimidazolium cation and bis ( sulfonic fluoro) imide anion ^{_{((FSO 2) 2 N -}} ) of the ionic liquid, and comprising a 4-methyl-octyl - pyridinium cations and bis (fluoromethyl sulfonylurea) imide anion ((FSO _{2) 2} N ^-) of the ionic liquid in at least either one.

[5] The adhesive composition according to any one of [1] to [4], wherein the (meth) acrylic resin (A) and the polyfunctional epoxy (meth) acrylate (B Content of the said polyfunctional epoxy (meth) acrylate (B) in the total amount of) is 10-70 mass%. [6] The adhesive composition according to any one of [1] to [5], in which the (meth) acrylic resin (A) and the polyfunctional epoxy (meth) acrylate are added to the (meth) acrylic resin (A). The total amount of (B) is 100 parts by mass, and 0.05 to 10 parts by mass of the hardener (C) is contained.

[7] The adhesive composition according to any one of [1] to [6], which contains the photopolymerization with respect to 100 parts by mass of the polyfunctional epoxy (meth) acrylate (B). The initiator (D) is 0.1 to 5 parts by mass. [8] The adhesive composition according to any one of [1] to [7], in which the (meth) acrylic resin (A) and the polyfunctional epoxy (meth) acrylate are added to the (meth) acrylic resin (A). The total of 100 parts by mass of (B) is 0.5 to 5 parts by mass containing the ionic liquid (E).

[9] An adhesive sheet comprising a sheet-like substrate and an adhesive layer formed on the substrate, and the adhesive layer includes the one described in any one of [1] to [8] Adhesive composition. [Inventive effect]

The adhesive composition according to the present invention can form an adhesive layer with sufficiently high adhesion before UV irradiation, and low adhesion and surface resistance after UV irradiation. In addition, since the adhesive sheet of the present invention has an adhesive layer containing the adhesive composition of the present invention formed on a sheet-shaped substrate, peeling and charging can be effectively suppressed.

Hereinafter, preferred examples of the adhesive composition and the adhesive sheet of the present invention will be described in detail. The present invention is not limited to the embodiments shown below. Changes, omissions, or additions may be made without departing from the scope of the present invention with respect to numerical values, amounts, ratios, characteristics, and the like. In order to solve the above-mentioned problems, the inventor of the present case has conducted in-depth discussions repeatedly. As a result, it was found that if it contains 1 to 5 mol% of the constituents including the (meth) acrylic monomer (a-1) derived from the SP value of 9.50 (cal / cm ³ ) ^0.5 or more, (Meth) acrylic resin (A) with a SP value of less than 9.50 (cal / cm ³ ) ^0.5 (meth) acrylic monomer (a-2), 95-99 mol% copolymer The adhesive composition of the polyfunctional epoxy (meth) acrylate (B), hardener (C), photopolymerization initiator (D), and ionic liquid (E) of the compound represented by formula (1). can.

The state of the adhesive composition before UV irradiation is that the functional groups of the (meth) acrylic resin (A) and the polyfunctional epoxy (meth) acrylate (B) are crosslinked with the hardener (C). Of the state. In the above-mentioned adhesive composition, as a preferable example of the (meth) acrylic resin (A), a (meth) acrylic monomer containing a (meth) acrylic monomer derived from an SP value of 9.50 (cal / cm ³ ) ^0.5 or more ( a-1) constituents 1 to 5 mole% and constituents 95 to 99 containing (meth) acrylic monomer (a-2) derived from SP value less than 9.50 (cal / cm ³ ) ^0.5 As a polyfunctional epoxy (meth) acrylate (B), it is possible to obtain high adhesion in the state before UV irradiation. Therefore, according to the above-mentioned adhesive composition, an adhesive layer having high adhesive force before UV irradiation can be formed.

Moreover, in the said adhesive composition, since the compound represented by said Formula (1) is used as a polyfunctional epoxy (meth) acrylate (B), the photopolymerization initiator (D) will be cracked when it irradiates UV. Then, the (meth) acrylfluorenyl group at both ends of the polyfunctional epoxy (meth) acrylate (B) and the ethylenically unsaturated group in the skeleton are polymerized to perform crosslinking. This reduces the adhesive force of the entire adhesive composition after UV irradiation. Therefore, according to the above-mentioned adhesive composition, an adhesive layer having low adhesive force after UV irradiation can be formed. In addition, since the above-mentioned adhesive composition is a copolymer containing an ionic liquid (E) and the (meth) acrylic resin (A) contains a specific component derived from a specific (meth) acrylic monomer in a specific ratio, Therefore, an adhesive layer in which the effect of the ionic liquid (E) is not hindered by the (meth) acrylic resin (A) and has a low surface resistance value can be formed.

Hereinafter, preferred examples of the adhesive composition and the adhesive sheet of the present invention will be described. "Adhesive composition" 之 The adhesive composition of this embodiment includes a (meth) acrylic resin (A), a polyfunctional epoxy (meth) acrylate (B), a hardener (C), and photopolymerization. Initiator (D) and ionic liquid (E). In addition, "(meth) acrylic acid" in this specification means "acrylic acid" or "methacrylic acid." The "(meth) acrylate" means "acrylate" or "methacrylate". The "(meth) acrylic monomer" means a monomer having "acryloxy" or "methacryloxy".

[(Meth) acrylic resin (A)] A preferred example of the (meth) acrylic resin (A) included in the adhesive composition of the present embodiment is one in which the SP value is 9.50 (cal / cm ³ ) The constituent components of the (meth) acrylic monomer (a-1) of ^0.5 or more (hereinafter referred to as "(meth) acrylic monomer (a-1)") and the SP value (Meth) acrylic monomer (a-2) below 9.50 (cal / cm ³ ) ^0.5 (hereinafter, referred to as "(meth) acrylic monomer (a-2)") Copolymer of constituents. The (meth) acrylic resin (A) may include the third monomer ((meth) acrylic monomer (a-1) (a-2), as long as the effect of the present embodiment is not impaired. ). The (meth) acrylic resin (A) may be used alone or in combination of two or more.

The (meth) acrylic-based monomer (a-1) includes a (meth) acrylic-based component in a synergistic effect due to the synergistic effect of the component derived from the (meth) acrylic-based monomer (a-1) The adhesive composition of the resin (A) can form a sufficiently high adhesive force before UV irradiation and good water resistance, and when peeled off after UV irradiation, the adhesive composition does not remain on the adhesive layer on the adhesive surface.

In the (meth) acrylic resin (A), a component derived from the (meth) acrylic monomer (a-1) and a component derived from the (meth) acrylic monomer (a-2) All are repeating units. In the (meth) acrylic resin (A), the order of arrangement of the repeating units is not particularly limited. Therefore, the (meth) acrylic resin (A) may be any of a random copolymer, a block copolymer, and an interpolymer.

The "SP value" in this specification refers to a calculated value calculated by Fedors' formula δ ² = ΣE / ΣV (δ is an SP value, E is an evaporation energy, and V is a mole volume.). The unit of the SP value is (cal / cm ³ ) ^0.5 . The method of Fedors is described in Journal of the Adhesion Society of Japan, 1986, Vol. 22, p. 566.

((Meth) acrylic monomer (a-1)) The constituent component derived from the (meth) acrylic monomer (a-1) contributes to the adhesion of the adhesive composition before UV irradiation. The (meth) acrylic monomer (a-1) may be a (meth) acrylic monomer (a-1) having an SP value of 9.50 (cal / cm ³ ) ^0.5 or more, and 15.0 (cal / cm ³ ) ^0.5 or less is preferred. The (meth) acrylic monomer (a-1) has an SP value of 10.0 (cal / cm ³ ) or more preferably ^{0.5, and} more preferably 11.0 (cal / cm ³ ) ^0.5 or more. The SP value of the (meth) acrylic monomer (a-1) is more preferably 13.0 (cal / cm ³ ) ^0.5 or less, and even more preferably 12.5 (cal / cm ³ ) ^0.5 or less.

Examples of the (meth) acrylic monomer (a-1) include tetrahydrofurfuryl acrylate (SP value 9.62 (cal / cm ³ ) ^0.5 ), and tetrahydrofurfuryl methacrylate (SP value). 9.54 (cal / cm ³ ) ^0.5 ), benzyl acrylate (SP value 10.14 (cal / cm ³ ) ^0.5 ), benzyl methacrylate (SP value 10.03 (cal / cm ³ ) ^0.5 ), glycidyl acrylate (SP value 9.91 (cal / cm ³ ) ^0.5 ), glycidyl methacrylate (SP value 9.79 (cal / cm ³ ) ^0.5 ), phenoxyethyl acrylate (SP value 10.12 (cal / cm ³ ) ^0.5 ), Phenoxyethyl methacrylate (SP value 10.02 (cal / cm ³ ) ^0.5 ), acrylic acid (SP value 11.08 (cal / cm ³ ) ^0.5 ), methacrylic acid (SP value 11.42 (cal / cm ³ ) ^0.5), 4-hydroxybutyl acrylate (SP value of ^{11.64 (cal / cm 3) 0.5} ), 4- hydroxymethyl-butyl acrylate (SP value of ^{11.39 (cal / cm 3) 0.5} ), 2- hydroxyethyl acrylate (Meth) acrylic monomers such as esters (SP value 12.45 (cal / cm ³ ) ^0.5 ), 2-hydroxyethyl methacrylate (SP value 12.06 (cal / cm ³ ) ^0.5 ), or N, N- Dimethacrylamide (SP value 10.60 (cal / cm ³ ) ^0.5 ), N, N-diethylacrylamide (SP value 10.20 (cal / cm ³ ) ^0.5 ), N-isopropylacrylamide (SP value 1 0.60 (cal / cm ³ ) ^0.5 ), N-hydroxyethyl acrylamide (SP value 14.40 (cal / cm ³ ) ^0.5 ), acrylamide (SP value 14.20 (cal / cm ³ ) ^0.5 ), etc. Based) acrylamide-based monomer, or N-vinylpyrrolidone (SP value 11.40 (cal / cm ³ ) ^0.5 ), N-vinyl caprolactam (SP value 10.80 (cal / cm ³ ) ^0.5 ), N- Vinylacetamide (SP value 10.90 (cal / cm ³ ) ^0.5 ), N-acrylic acid morpholine (SP value 11.20 (cal / cm ³ ) ^0.5 ), acrylonitrile (SP value 11.10 (cal / cm ³ ) ^0.5 ) and so on.

Among the above (meth) acrylic monomers (a-1), acrylic acid, methacrylic acid, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, and N, N-dimethylacrylic acid Amine and N, N-diethylacrylamide are more suitable, and acrylic acid and 2-hydroxyethylacrylate are particularly suitable. The aforementioned (meth) acrylic monomer (a-1) may be used alone or in combination of two or more kinds.

The (meth) acrylic resin (A) is a copolymer containing 1 to 5 mol% of the constituent components derived from the (meth) acrylic monomer (a-1) described above. If the content of the component derived from the (meth) acrylic monomer (a-1) is less than 1 mol%, the adhesive force of the adhesive composition before UV irradiation is insufficient. In addition, if the content of the constituent component derived from the (meth) acrylic monomer (a-1) is less than 1 mol%, an adhesive sheet having an adhesive layer containing an adhesive composition is attached to the adhesive. When peeling after the body, the adhesive layer becomes easy to remain on the adherend. In addition, if the content of the constituent component derived from the (meth) acrylic monomer (a-1) exceeds 5 mol%, the amount of the (meth) acrylic resin (A) to the ionic liquid (E) Obstacles to effect become significant. As a result, an adhesive sheet having an adhesive layer containing an adhesive composition cannot be a sufficiently low surface resistance value after UV irradiation, and cannot sufficiently prevent peeling and charging. When the content of the constituent component derived from the (meth) acrylic monomer (a-1) exceeds 5 mol%, there are those derived from the constituent component of the (meth) acrylic monomer (a-2). Insufficient content and insufficient water-resistant adhesion of the adhesive composition before UV irradiation. In addition, the (meth) acrylic resin (A) has a constituent component derived from the (meth) acrylic monomer (a-1) of 1 to 5 mol%. However, it can be arbitrarily selected within this range. For example, as needed, the amount of the foregoing components may be 1 to 3 mole%, may be 1 to 4 mole%, may be 2 to 4 mole%, may be 2 to 5 mole%, or may be 3 to 3 mole%. 5 mol% and so on.

((Meth) acrylic monomer (a-2)) The constituent component derived from (meth) acrylic monomer (a-2) is the main component of (meth) acrylic resin (A). Helps the water-resistant adhesion of the adhesive composition before UV irradiation. If the (meth) acrylic monomer (a-2) is a (meth) acrylic monomer (a-2) having an SP value exceeding 0 (cal / cm ³ ) ^0.5 and less than 9.50 (cal / cm ³ ) ^0.5 ). The (meth) acrylic monomer (a-2) has an SP value of 8.0 (cal / cm ³ ) or more, preferably ^{0.5, and} more preferably 8.5 (cal / cm ³ ), ^0.5 or more. The SP value of the (meth) acrylic monomer (a-2) is preferably 9.0 (cal / cm ³ ) ^0.5 or less.

Examples of the (meth) acrylic monomer (a-2) include methacrylate (SP value 8.95 (cal / cm ³ ) ^0.5 ), and methyl methacrylate (SP value 8.93 (cal / cm ³ ) ^0.5 ), ethyl acrylate (SP value 8.89 (cal / cm ³ ) ^0.5 ), ethyl methacrylate (SP value 8.88 (cal / cm ³ ) ^0.5 ), n-butyl acrylate (SP value 8.82 (cal / cm ³ ) ^0.5 ), n-butyl methacrylate (SP value 8.82 (cal / cm ³ ) ^0.5 ), cyclohexyl acrylate (SP value 9.26 (cal / cm ³ ) ^0.5 ), methacrylic acid Cyclohexyl (SP value 9.22 (cal / cm ³ ) ^0.5 ), 2-ethylhexyl acrylate (SP value 8.62 (cal / cm ³ ) ^0.5 ), ethyl 2-hexyl methacrylate (SP value 8.63 ( cal / cm ³ ) ^0.5 ), isofluorenyl acrylate (SP value 8.70 (cal / cm ³ ) ^0.5 ), and the like.

Among the (meth) acrylic monomers (a-2) mentioned above, methacrylate, methyl methacrylate, ethacrylate, n-butyl acrylate, 2-ethylhexyl acrylate, isopropyl A fluorenyl acrylate is more suitable, and especially methyl methacrylate, ethyl acrylate, n-butyl acrylate, and 2-ethylhexyl acrylate are more suitable. The aforementioned (meth) acrylic monomer (a-2) may be used alone or in combination of two or more kinds.

The (meth) acrylic resin (A) is a copolymer containing 95 to 99 mol% of the constituent components derived from the (meth) acrylic monomer (a-2) described above. If the content of the constituent component derived from the (meth) acrylic monomer (a-2) is 95 mol% or more, it will become an adhesive composition with high water-resistant adhesion before UV irradiation. An adhesive sheet having an adhesive layer containing an adhesive composition with a high water-resistant adhesive force before UV irradiation is suitable for use in attaching a wafer to a dicing step. If the content of the constituent component derived from the (meth) acrylic monomer (a-2) is less than 95 mol%, the adhesive composition before UV irradiation has insufficient water-resistant adhesion. When the content of the constituent component derived from the (meth) acrylic monomer (a-2) exceeds 99 mol%, the content of the constituent component derived from the (meth) acrylic monomer (a-1) Insufficient, and the adhesive composition of the adhesive composition before UV irradiation is insufficient. In addition, the component derived from the (meth) acrylic monomer (a-2) in the (meth) acrylic resin (A) is 95 to 99 mol%, but it can be arbitrarily selected within this range. For example, the amount of the aforementioned component may be 95 to 97 mol%, 96 to 99 mol%, or 97 to 99 mol% as needed.

The weight average molecular weight of the (meth) acrylic resin (A) is preferably from 200,000 to 2 million series, more preferably from 200,000 to 1.5 million series, and even more preferably from 400,000 to 1 million series. If the weight average molecular weight of the (meth) acrylic resin (A) is 200,000 or more, when an adhesive sheet having an adhesive layer containing an adhesive composition is attached to the adherend and peeled off, the adhesive layer The line becomes difficult to remain on the adherend. When the weight average molecular weight of the (meth) acrylic resin (A) is 2 million or less, the viscosity of the (meth) acrylic resin (A) does not become too high, and the effect of good workability can be obtained.

The weight-average molecular weight of the (meth) acrylic resin (A) was measured using a gel permeation chromatography (manufactured by Showa Denko Corporation, Shodex (registered trademark) GPC-101) under the following conditions at normal temperature. Calculated based on styrene. Column: Shodex (registered trademark) LF-804 manufactured by Showa Denko Corporation Column temperature: 40 ° C Sample: 0.2% by mass tetrahydrofuran solution of copolymer 共聚物 Flow rate: 1ml / min Eluent: Tetrahydrofuran

The glass transition temperature (Tg) of the (meth) acrylic resin (A) is preferably -80 to 0 ° C, more preferably -60 to -10 ° C, and more preferably -40 to -10 ° C. If the glass transition temperature of the (meth) acrylic resin (A) is -80 ° C or higher, the compatibility between the (meth) acrylic resin (A) and the polyfunctional epoxy (meth) acrylate (B) will change. good. As a result, it becomes an adhesive composition with sufficiently small adhesive force after UV irradiation. Therefore, when an adhesive sheet having an adhesive layer containing an adhesive composition is attached to the adherend and peeled off, the adhesive layer system does not easily remain on the adherend. In addition, when the glass transition temperature of the (meth) acrylic resin (A) is 0 ° C or lower, the adhesive force of the adhesive composition before UV irradiation becomes good.

The glass transition temperature (Tg) of the (meth) acrylic resin (A) refers to one obtained by the following method. Extract a 10 mg sample from the (meth) acrylic resin (A). Using a differential scanning calorimeter (DSC), the sample temperature was changed from -80 ° C to 200 ° C at a heating rate of 10 ° C / min, and a differential scanning calorimetry was performed to start with the endothermicity caused by the observed glass transition The temperature is taken as Tg. When two Tgs are observed, the average of the two Tgs is taken.

(Manufacturing method of (meth) acrylic resin (A)) The manufacturing method of (A) (meth) acrylic resin (A) is not specifically limited. For example, a raw material sheet including the (meth) acrylic monomer (a-1) and the (meth) acrylic monomer (a-2) which are the constituents of the (meth) acrylic resin (A) can be used. It is obtained by copolymerization by a known polymerization method. Specifically, as the polymerization method, a solution polymerization method, an emulsion polymerization method, a block polymerization method, a suspension polymerization method, an interactive copolymerization method, or the like can be used. Among these polymerization methods, from the viewpoints of transparency and cost of the (meth) acrylic resin (A) obtained after polymerization, it is preferable to use a solution polymerization method.

When the (meth) acrylic resin (A) is produced by a solution polymerization method, a polymerization initiator and / or a solvent are used as necessary. Rhenium is not particularly limited as a polymerization initiator, and can be appropriately selected from known materials and used. Examples of the polymerization initiator include 2,2'-azobis (isobutyronitrile), 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (2-methylbutyronitrile), 1,1'-azobis (cyclohexane- 1-Carbonate), 2,2'-azobis (2,4,4-trimethylpentane), dimethyl-2,2'-azobis (2-methylpropionate), etc. Azo-based polymerization initiators: Benzamidine peroxide, t-butyl hydroperoxide, di-t-butyl peroxide, t-peroxybenzoate, bisisophenylpropyl peroxide Compounds, 1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane, 1,1-bis (t-butylperoxy) cyclododecane, etc. Although it is an oil-soluble polymerization initiator such as an oxide-based polymerization initiator, other oil-soluble polymerization initiators may be used.

These polymerization initiators may be used alone or in combination of two or more. The amount of the polymerization initiator used is 0.01 to 5 parts by mass based on 100 parts by mass of the total of the (meth) acrylic monomer (a-1) and the (meth) acrylic monomer (a-2). The system is preferably, 0.02 to 4 parts by mass is more preferable, and 0.03 to 3 parts by mass is even more preferable.

As the solvent, various general solvents can be used. Examples of the solvent system include ethyl acetate, esters such as n-propyl acetate and n-butyl acetate, aromatic hydrocarbons such as toluene and benzene, and fats such as n-hexane and n-heptane. Organic solvents such as family hydrocarbons, alicyclic hydrocarbons such as cyclohexane and methylcyclohexane, and ketones such as methyl ethyl ketone and methyl isobutyl ketone.溶剂 These solvents can be used alone or in combination of two or more.

[Multifunctional epoxy (meth) acrylate (B)] The multifunctional epoxy (meth) acrylate (B) included in the adhesive composition of this embodiment is formed by UV irradiation on the adhesive composition. To form a three-dimensional cross-linked structure. When a three-dimensional crosslinked structure is formed, the adhesive force of the adhesive composition is reduced. The polyfunctional epoxy (meth) acrylate (B) is a modified product of the epoxy (meth) acrylate, and is a compound represented by the following formula (1).

(In formula (1), R ¹ is a hydrogen atom or a methyl group, and may be the same or different. R ² is a hydrogen atom or a group having an ethylenically unsaturated bond. R ³ is a hydrogen atom or a group having an ethylenically unsaturated bond R ³ has at least one ethylenically unsaturated bond when n is 1 and R ² is a hydrogen atom. When R ³ is n or more and R ² is a hydrogen atom, R ^{3 is} plural. Some or all of the R ³ systems have at least one ethylenically unsaturated bond. X is a base having a ring structure; n is a positive integer)

In the formula (1), R ¹ is a hydrogen atom or a methyl group, and may be the same or different. In the formula (1), R ² is a hydrogen atom or a group having an ethylenically unsaturated bond. In the case where R ² is a group having an ethylenically unsaturated bond, from the viewpoint of photopolymerization, it is preferably any one selected from the group consisting of acrylfluorenyl and methacrylfluorenyl. When R ² is a hydrogen atom (in other words, when a hydroxyl group is formed), the hydroxyl group containing R ² helps to pass through the (meth) acrylic resin of the hardener (C) in the adhesive composition before UV irradiation. (A) and a cross-linked structure of a polyfunctional epoxy (meth) acrylate (B). When R ² is an ethylenically unsaturated group, if the photopolymerization initiator (D) is cleaved due to UV irradiation of the adhesive composition, the polyfunctional epoxy (meth) acrylate (B) The (meth) acrylfluorenyl group at both ends and the ethylenically unsaturated group of R ² are polymerized and crosslinked. As a result, the adhesive force of the adhesive composition after UV irradiation becomes smaller, which is preferable.

In the formula (1), R ³ is a hydrogen atom or a group having an ethylenically unsaturated bond. When R ³ is a hydrogen atom (in other words, when a hydroxyl group is formed), the hydroxyl group containing R ³ is a (meth) acrylic resin that helps to penetrate the hardener (C) in the adhesive composition before UV irradiation. (A) and a cross-linked structure of a polyfunctional epoxy (meth) acrylate (B). In the case where R ³ is a group having an ethylenically unsaturated bond, if the photopolymerization initiator (D) is cleaved due to UV irradiation of the adhesive composition, the polyfunctional epoxy (meth) acrylate (B) A (meth) acrylfluorenyl group at both ends and an ethylenically unsaturated group of R ³ are polymerized and crosslinked. As a result, the adhesive force of the adhesive composition after UV irradiation becomes smaller, which is preferable.

When n in Formula (1) is 1 and R ² is a hydrogen atom, the R ³ system has at least one ethylenically unsaturated bond. In the case of formula (1) wherein n is 2 or more and R ² is a hydrogen atom, from among the plurality of R ³ R ³ a part or all of at least one ethylenically unsaturated bond. In the case where R ³ has at least one ethylenically unsaturated bond, from the viewpoint of photopolymerization of the adhesive composition, it is preferably any one selected from the group consisting of acrylfluorenyl and methacrylfluorenyl.

In the total of R ² and R ³ in formula (1), the ratio of the number of groups having ethylenically unsaturated bonds is preferably 30 to 90%, more preferably 35 to 85%, and 40 to 80%. Department is even better. If the ratio of the number of the groups having an ethylenically unsaturated bond is 30% or more, the adhesive force of the adhesive composition after UV irradiation becomes smaller, which is preferable. If the ratio of the number of the groups having an ethylenically unsaturated bond is 90% or less, the adhesive layer after peeling is less likely to remain, so it is preferable.

Among the total of R ² and R ³ , the ratio of the number of groups having ethylenically unsaturated bonds can be defined by a known method such as ¹ H-NMR. In addition, in the total of R ² and R ³ , the ratio of the number of the groups having ethylenically unsaturated bonds can be determined by the amount of the material used to produce the polyfunctional epoxy (meth) acrylate (B) (feed in Amount) to calculate.

In the formula (1), X is a group having a ring structure. Examples of the base having a ring structure include a base having two six-membered ring structures and a structure in which a divalent linking group composed of a hydrocarbon is bonded. An adhesive composition containing a polyfunctional epoxy (meth) acrylate (B) containing such a group is preferable because the adhesive force of the adhesive composition after UV irradiation is sufficiently reduced. X It is preferable that X in the formula (1) is a base represented by the formula (2) or a base represented by the formula (3).

(In formula (2), R ⁴ is a hydrogen atom or a methyl group, and may be the same or different, respectively).

(In formula (3), R ⁵ is a hydrogen atom or a methyl group, and may be the same or different, respectively).

R (2) and in the formula ⁴ (3) R ⁵ is a hydrogen atom or a methyl group, may be the same or different. Formula (2) 2 R ⁴ (in the formula (3) 2 R ⁵⁾ is preferably the same system. Specific examples of X in the formula (1) include the groups represented by the following general formulae (1-2) to (1-5).

In the formula (1), n is a positive integer, 1 to 20 is preferable, and 1 to 5 is more preferable. If n is 20 or less, the viscosity will not become too high, and the operability will be good.

The polyfunctional epoxy (meth) acrylate (B) may be a compound represented by formula (1), and it may be used alone or in combination of two or more.

The content of the polyfunctional epoxy (meth) acrylate (B) in the total amount of the (meth) acrylic resin (A) and the polyfunctional epoxy (meth) acrylate (B) is 10 to 70% by mass It is more preferable, 10 to 65% by mass is more preferable, and 20 to 60% by mass is even more preferable. If necessary, it may be 15 to 60% by mass, 15 to 55% by mass, or the like. If the content of the polyfunctional epoxy (meth) acrylate (B) in the total amount is 10% by mass or more, a three-dimensional crosslinked structure is sufficiently formed by UV irradiation of the adhesive composition. As a result, since the adhesive force of the adhesive composition after UV irradiation is sufficiently reduced, it is preferable. If the content of the polyfunctional epoxy (meth) acrylate (B) in the total amount is 70% by mass or less, the (meth) acrylic resin (A) is not insufficient and the cohesive force of the adhesive composition is insufficient. In this case, the adhesive force of the adhesive composition before UV irradiation becomes good.

(Manufacturing method of polyfunctional epoxy (meth) acrylate (B)) The manufacturing method of the polyfunctional epoxy (meth) acrylate (B) contained in an adhesive composition is not specifically limited. The polyfunctional epoxy (meth) acrylate (B) is produced, for example, by a method of introducing an ethylenically unsaturated bond into an epoxy (meth) acrylate.

The epoxy (meth) acrylate used in the production of the polyfunctional epoxy (meth) acrylate (B) is an α, β-unsaturation having an epoxy group of 50 mol% or more relative to the epoxy group of the epoxy resin. Monobasic acid derived. In the production of epoxy (meth) acrylate, it is preferred to react an α, β-unsaturated monobasic acid having an epoxy group content of 80 mol% or more with respect to the epoxy resin. The epoxy (meth) acrylate may have an unreacted epoxy group in the molecule.

The α, β-unsaturated monobasic acid can be reacted with an epoxy resin by a conventionally known method. When the α, β-unsaturated monoacid is reacted with an epoxy resin to synthesize an epoxy (meth) acrylate, a catalyst and / or a polymerization inhibitor may be used as required. As the catalyst system, for example, a conventionally known catalyst such as triphenylphosphine can be used. As the polymerization inhibitor system, for example, a conventionally known polymerization inhibitor such as methyl hydroquinone can be used.

Epoxy (meth) acrylates are described in, for example, "Takayama Eiichiro, Polyester resin handbook" (edited by Nikkan Kogyo Shimbun, 1988) or "Dictionary of Coatings" (edited by Japan Society of Colour Material, 1993).

Examples of the α, β-unsaturated monobasic acid used in the production of epoxy (meth) acrylates include acrylic acid and methacrylic acid.

Examples of the epoxy resin used in the production of epoxy (meth) acrylates include bisphenol type (for example, biphenol, bisphenol A, hydrogenated bisphenol A, bisphenol F, bisphenol S, bis Phenol SH, bisphenol Z, 4,4'-dihydroxybenzophenone, 2,4'-dihydroxybenzophenone, bis (4-hydroxyphenyl) fluorene, catechol, resorcinol , Bisphenols such as hydroquinone, dihydroxynaphthalene, tetrachlorobisphenol A, etc.) epoxy resins, novolac type (phenol novolac, cresol novolac, bisphenol A novolac, dicyclopentane (Ene-phenol novolac, etc.) epoxy resin, naphthol aralkyl epoxy resin, phenol aralkyl epoxy resin, tetrahydroxyphenylethane epoxy resin, cyclic aliphatic epoxy resin, Triglycidyl isotricyanate and epoxy resins having halogen atoms such as bromine atoms introduced therein. Epoxy resins other than these epoxy resins can also be used.

Among these epoxy resins, bisphenol A type, bisphenol F type, hydrogenated bisphenol A type, and hydrogenated bisphenol F type are preferably used. A polyfunctional epoxy (meth) acrylate (B) -containing adhesive composition produced using these epoxy resins is preferable because the adhesive force of the adhesive composition after UV irradiation is sufficiently reduced. These epoxy resins can be used alone or in combination of two or more.

X in formula (1) is a polyfunctional epoxy (meth) acrylate (B) represented by formula (2) and R ⁴ in formula (2) is a methyl group by using a bisphenol A ring Oxygen resin is obtained as an epoxy resin for epoxy (meth) acrylate material. In addition, X in formula (1) is a polyfunctional epoxy (meth) acrylate (B) represented by formula (2) and R ⁴ in formula (2) is a hydrogen atom by using bisphenol F Type epoxy resin is obtained as an epoxy resin of epoxy (meth) acrylate material. X in formula (1) is a polyfunctional epoxy (meth) acrylate (B) represented by formula (3) and R ⁵ in formula (3) is a methyl group by using a hydrogenated bisphenol A type An epoxy resin is obtained as an epoxy resin of an epoxy (meth) acrylate material.

The method for introducing an ethylenically unsaturated bond into an epoxy (meth) acrylate to produce a polyfunctional epoxy (meth) acrylate (B) is not particularly limited, but examples thereof include an epoxy (meth) acrylate (B). Method for reacting a secondary hydroxyl group in a (meth) acrylate with an α, β-ethylenically unsaturated monoisocyanate, and adding an unsaturated anhydride-containing acid anhydride to the secondary hydroxyl group in an epoxy (meth) acrylate Method, etc.

When introducing an ethylenically unsaturated bond into an epoxy (meth) acrylate, the hydrogen atoms of all the secondary hydroxyl groups in the epoxy (meth) acrylate molecule of the raw material can be replaced with a group having an ethylenically unsaturated bond. . In this case, for example, a polyfunctional epoxy (meth) acrylate (B) in which both R ² and R ³ in the formula (1) are a group having an ethylenically unsaturated bond can be obtained.

When an ethylenically unsaturated bond is introduced into an epoxy (meth) acrylate, only a part of the hydrogen atoms of the secondary hydroxyl group in the epoxy (meth) acrylate molecule of the raw material can be replaced with an ethylenically unsaturated bond. The base. That is, the secondary hydroxyl group may remain in the polyfunctional epoxy (meth) acrylate (B) as it is. In this case, for example, a polyfunctional epoxy (meth) acrylate (B) in which either of R ² and R ³ in the formula (1) is a group having an ethylenically unsaturated bond can be obtained. In addition, when n in the formula (1) is 2 or more, R ³ is a group having an ethylenically unsaturated bond, not only when all R ³ is a group having an ethylenically unsaturated bond, but also includes plural When only a part of R ³ among R ³ is a group having an ethylenically unsaturated bond.

In the case of using a method for reacting an α, β-ethylenically unsaturated monoisocyanate with a secondary hydroxyl group in an epoxy (meth) acrylate, examples of the α, β-ethylenically unsaturated monoisocyanate include, for example, Methacrylfluorenyl isocyanate, isocyanatoethyl methacrylate, 2-isocyanatoethyl acrylate, 1,1-bispropenyloxymethylethyl isocyanate, and the like.

Among these α, β-ethylenically unsaturated monoisocyanates, preferred are isocyanatoethyl acrylate, isocyanatoethyl methacrylate, and 1,1-bispropenyloxymethylethyl. Isocyanate. Adhesive composition containing polyfunctional epoxy (meth) acrylate (B) produced by using these α, β-ethylenically unsaturated monoisocyanates has sufficient adhesive force after UV irradiation It is smaller, so it is better.

The ratio of α, β-ethylenically unsaturated monoisocyanate which reacts with the secondary hydroxyl group in epoxy (meth) acrylate is 1 mole, α with respect to the secondary hydroxyl group in epoxy (meth) acrylate. β-ethylenically unsaturated monoisocyanate is preferably 0.3 to 0.9 moles, more preferably 0.35 to 0.9 moles, and more preferably 0.4 to 0.9 moles. If the ratio of α, β-ethylenically unsaturated monoisocyanate is 0.3 mol or more, the hydrogen atom of the secondary hydroxyl group of the epoxy (meth) acrylate molecule contained in the raw material will be substituted with an ethylenically unsaturated compound. The number of bases of saturated bonds is sufficiently increased. As a result, it becomes the adhesive composition containing the polyfunctional epoxy (meth) acrylate (B) which has many ethylenically unsaturated bonds, and it becomes a person with sufficient cohesion. In addition, if the ratio of α, β-ethylenically unsaturated monoisocyanate is 0.3 mol or more, an adhesive layer is included, the adhesive layer includes an adhesive composition, and the adhesive composition includes When the adhesive sheet of the polyfunctional epoxy (meth) acrylate (B) is attached to the adherend and peeled off, the adhesive layer system does not easily remain on the adherend. If the ratio of α, β-ethylenically unsaturated monoisocyanate is 0.9 mol or less, the remaining hydroxyl group is crosslinked with the cross-linking agent (C), so it has sufficient cohesive force, and the adhesive layer after peeling The system becomes difficult to remain.

The reaction between the secondary hydroxyl group in the epoxy (meth) acrylate and the α, β-ethylenically unsaturated monoisocyanate is an addition reaction, and the conditions for general urethane reaction can be used. For example, when reacting a secondary hydroxyl group in an epoxy (meth) acrylate with an α, β-ethylenically unsaturated monoisocyanate, dibutyltin dilaurate, dioctyltin dilaurate, and diazonium can be used as required. So-called urethane catalysts such as heterobicyclooctane (DABCO) are reacted in the presence or absence of a solvent.

When the method of adding an unsaturated group-containing acid anhydride to a secondary hydroxyl group in an epoxy (meth) acrylate is used, it is preferable to add anhydrous (meth) acrylic acid as an unsaturated group-containing acid anhydride.

The ratio of the unsaturated group-containing anhydride which reacts with the secondary hydroxyl group in the epoxy (meth) acrylate is 1 mole with respect to the secondary hydroxyl group in the epoxy (meth) acrylate. The acid anhydride is preferably 0.3 to 0.9 moles, and more preferably 0.4 to 0.9 moles. If the ratio of the unsaturated anhydride-containing acid anhydride is 0.3 mol or more, the hydrogen atom of the secondary hydroxyl group of the epoxy (meth) acrylate molecule contained in the raw material is substituted with a group having an ethylenically unsaturated bond. The number of participants has increased sufficiently. As a result, it becomes the adhesive composition containing the polyfunctional epoxy (meth) acrylate (B) which has many ethylenically unsaturated bonds, and it becomes a person with sufficient cohesion. In addition, if the ratio of the unsaturated anhydride-containing acid anhydride is 0.3 mol or more, an adhesive layer is provided, the adhesive layer includes an adhesive composition, and the adhesive composition includes a polyfunctional epoxy produced by using the adhesive layer. When the (meth) acrylate (B) adhesive sheet is attached to the adherend and peeled off, the adhesive layer system does not easily remain on the adherend. If the ratio of the unsaturated anhydride-containing acid anhydride is 0.9 mol or less, the remaining hydroxyl group is crosslinked with the crosslinking agent (C), so it has sufficient cohesive force, and the adhesive layer system after peeling becomes difficult. Residual.

[Hardener (C)] 之 The hardener (C) contained in the adhesive composition of the present embodiment is not particularly limited as long as it has two or more functional groups that are reactive to a hydroxyl group, a carboxyl group, or an epoxy group. , And is not limited to those who react with other functional groups.

Examples of the curing agent (C) include 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, hydrogenated toluene diisocyanate, 1,3-benzenedimethyldiisocyanate, and 1,4-benzenediisocyanate. Methyl diisocyanate, diphenylmethane-4,4-diisocyanate, isophorone diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, tetramethylxylylene diisocyanate , 1,5-naphthalene diisocyanate, toluene diisocyanate adduct of trimethylolpropane, xylylene diisocyanate adduct of trimethylolpropane, triphenylmethane triisocyanate, methylenebis ( 4-phenylmethane) isocyanate-based compounds such as triisocyanate, bisphenol A · epoxychloropropane type epoxy resin, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerol diglycidyl ether , Glycerol triglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl glycerol Epoxy compounds such as sugar alcohols, diglycerol polyglycidyl ether, Tetramethylolmethane-tri-β-aziridinylpropionate, trimethylolpropane-tri-β-aziridinylpropionate, N, N′-diphenylmethane-4,4 ′ -Aziridine-based compounds such as bis (1-aziridinecarboxamide), N, N′-hexamethylene-1,6-bis (1-aziridinecarboxamide), hexahexamethoxymethyl Melamine-based compounds such as melamine, hexaethoxymethyl melamine, hexapropoxymethyl melamine, hexamethylol melamine, hexapentoxymethyl melamine, hexahexyloxymethyl melamine, and the like.

Among these hardeners (C), since the reactivity with the (meth) acrylic resin (A) and the polyfunctional epoxy (meth) acrylate (B) is good, an isocyanate-based compound is preferably used. The aforementioned hardener (C) can be used alone or in combination of two or more.

The hardener (C) contained in the adhesive composition is 0.05 to 10 parts by mass based on 100 parts by mass of the total amount of the (meth) acrylic resin (A) and the polyfunctional epoxy (meth) acrylate (B). Mass parts are preferred, and 0.1 to 5 mass parts are more preferred. If necessary, it may be 0.5 to 3 parts by mass, or 1 to 4 parts by mass. When the content of the hardener (C) is 0.05 parts by mass or more with respect to 100 parts by mass of the total amount described above, the adhesive composition system forms a sufficient three-dimensional crosslinked structure. As a result, since the adhesive force of the adhesive composition after UV irradiation is sufficiently reduced, it is preferable. When the content of the curing agent (C) is 10 parts by mass or less, the adhesive force of the adhesive composition before UV irradiation is good.

[Photopolymerization initiator (D)] As the photopolymerization initiator (D) included in the adhesive composition of this embodiment, for example, benzophenone, diphenylethylenedione, and benzoin are mentioned. , Ω-bromoacetophenone, chloroacetone, acetophenone, 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, p-dimethylamino Acetophenone, p-dimethylaminophenylacetone, 2-chlorobenzophenone, 4,4'-dichlorobenzophenone, 4,4'-bisdiethylaminobenzophenone, Mich Ketone, benzoin methyl ether, benzoin isobutyl ether, benzoin-n-butyl ether, benzyl methyl ketal, 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-benzene -Propane-1-one, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropane-1-one, methylbenzylmethylformate, 2,2-diethyl Oxyacetophenone, 4-N, N'-dimethylacetophenone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinylpropane-1-one, etc. Carbonyl-based photopolymerization initiator.

As the photopolymerization initiator (D), thioether-based light such as diphenyl disulfide, dibenzyl disulfide, tetraethylthiuram disulfide, and tetramethylammonium monosulfide can also be used. Polymerization initiator; fluorenyl groups such as 2,4,6-trimethylbenzylidene diphenylphosphine oxide, 2,4,6-trimethylbenzylidenephenylethoxyphosphine oxide, etc. Phosphine oxides; quinone-based photopolymerization initiators such as benzoquinone and anthraquinone; sulfonyl chloride-based photopolymerization initiators; thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, etc. Thioxanthone-based photopolymerization initiators and the like.

Among these photopolymerization initiators (D), from the viewpoint of solubility to the adhesive composition, it is preferable to use 1-hydroxycyclohexylphenyl ketone and / or 2,4,6-trimethyl ether. Benzamidinediphenylphosphine oxide. The photopolymerization initiator (D) mentioned above can be used alone or in combination of two or more kinds.

The photopolymerization initiator (D) contained in the adhesive composition is preferably 0.1 to 5 parts by mass, and 0.3 to 3.5 parts by mass based on 100 parts by mass of the polyfunctional epoxy (meth) acrylate (B). It is more preferable, and 0.5 to 2.0 parts by mass is even more preferable. If necessary, it may be 0.2 to 3 parts by mass or 0.2 to 1.5 parts by mass. If the content of the photopolymerization initiator (D) with respect to 100 parts by mass of the polyfunctional epoxy (meth) acrylate (B) is 0.1 parts by mass or more, the UV-ray irradiation will cause the adhesive composition to be sufficiently formed. At the same time of rapid curing, the adhesive force of the adhesive composition after UV irradiation is sufficiently reduced, which is preferable. When the content of the photopolymerization initiator (D) is 5 parts by mass or less, when an adhesive sheet having an adhesive layer containing an adhesive composition is attached to the adherend and peeled off, the adhesive layer system becomes Not easy to remain on the adherend. In addition, even when the content of the photopolymerization initiator (D) exceeds 5 parts by mass, an effect according to the content of the photopolymerization initiator (D) cannot be observed.

[Ionic liquid (E)] 之 The ionic liquid (E) contained in the adhesive composition of this embodiment improves the antistatic property of the adhesive composition. The ionic liquid refers to a molten salt compound (ionic compound) having a melting point of 100 ° C or lower. The melting point of the ionic liquid is preferably below room temperature (25 ° C). The ionic liquid (E) can be used alone or in combination of two or more.

As the ionic liquid (E), an organic salt compound using a combination of an organic cation and an inorganic anion or an organic anion is preferably used. Examples of the organic cation constituting the ionic liquid (E) include onium. Specifically, as the organic cation, ammonium (representative structure: Q ¹ ₄ N ⁺ ), imine (representative structure: Q ² ₂ C = N ⁺ Q ¹ ₂ ), and ammonium (representative structure) : Q ¹ ₃ S ⁺ ), oxonium (representative structure: Q ¹ ₂ O ⁺ ), osmium of fourth-order phosphorus atom (representative structure: Q ¹ ₄ P ⁺ ), iodonium (representative structure: Q ¹ ₂ I ⁺ )Wait.

In the representative structure of the organic cation described above, Q ¹ represents a substituent such as an alkyl group, an aryl group, or a heterocyclic group. Q ² represents a hydrogen atom or a substituent. The complex number Q ¹ in the molecule, the complex number Q ² in the molecule, or the Q ¹ and Q ² in the molecule may be combined with each other to form a ring. In addition, it may be a base in which two Q ¹ or two Q ² in the molecule together form a double bond (for example, = O, = S, = NQ ² ).

Among the above-mentioned organic cations, ammonium, imine, and osmium of the fourth-order nitrogen atom are preferred. Examples of such organic cations include pyridinium cation, piperidinium cation, pyrrolidinium cation, imidazolium cation, tetrahydropyrimidinium cation, dihydropyrimidinium cation, pyrazolium cation, and tetraalkyl Ammonium cation, trialkylphosphonium cation, etc. Among these organic cations, imidazolium cations and pyridinium cations are preferably used.

The adhesive composition containing an ionic liquid (E) using an imidazolium cation or a pyridinium cation as an organic cation is excellent in antistatic properties. In addition, when an adhesive sheet having an adhesive layer containing an adhesive composition is attached to a wafer and a dicing step is performed, it is preferable because the wafer after the dicing step has excellent pick-up properties.

Specific examples of the imidazolium cation used as the organic cation include, for example, 1-methylimidazolium cation, 1-ethyl-3-methylimidazolium cation, and 1-ethyl-2,3-dimethyl Base imidazolium cation, 1-butyl-3-methylimidazolium cation, 1,2,3-trimethylimidazolium cation, and the like. Among these imidazolium cations, 1-ethyl-3-methylimidazolium cation is preferably used.

Specific examples of the pyridinium cation used as the organic cation include, for example, 1-ethylpyridinium cation, 1-butylpyridinium cation, 1-hexylpyridinium cation, and 1-butyl-3-methyl Pyridinium cation, 1-butyl-4-methylpyridinium cation, 1-hexyl-3-methylpyridinium cation, 1-hexyl-4-methylpyridinium cation, 1-butyl-3,4- Dimethylpyridinium cation and the like. Among these pyridinium cations, 1-hexyl-4-methylpyridinium cation, 4-methyl-1-octyl-pyridinium cation and the like are preferably used.

The inorganic anion constituting the ionic liquid (E) is not particularly limited as long as it satisfies the conditions for becoming an ionic liquid. As the inorganic anion, can include, for example, ^{based, Cl -, Br -, I} -, AlCl 4 -, Al 2 Cl 7 -, BF 4 -, PF 6 -, ClO 4 -, NO 3 -, AsF 6 -, SbF _{^{6 -, NbF 6 -, TaF}} 6 -, F (HF) m - (. m represents an integer of _{0), (CN) 2 N} - and the like.

The organic anion constituting the ionic liquid (E) is not particularly limited as long as it satisfies the conditions for becoming an ionic liquid. The organic anion may be based include ^{_{CH 3 COO -, CF 3 COO}} -, CH 3 SO 3 -, CF 3 SO 3 -, (CF 3 SO 2) 2 N -, (FSO 2) 2 N -, ( ^{_{CF 3 SO 2) 3 C -}} , C 4 F 9 SO 3 -, (C 2 F 5 SO 2) 2 N -, C 3 F 7 COO -, (CF 3 SO 2) (CF 3 CO) N - like .

As the inorganic anion or organic anion constituting the ionic liquid (E), among the above, an anion containing a fluorine atom is particularly preferably used. By using an anion containing a fluorine atom, an ionic liquid (E) having excellent ion conductivity is obtained. Among anions containing fluorine atoms, fluorine-containing organic anion is preferred, particularly preferred to use lines ^{_{(FSO 2) 2 N -,}} (CF 3 SO 2) 2 N -. Adhesive composition systems containing (FSO ₂ ) ₂ N ^- and (CF ₃ SO ₂ ) ₂ N ^- as an organic anion ionic liquid (E) are particularly excellent in antistatic properties.

As the ionic liquid (E), a commercially available product can also be used. Among the commercially available ionic liquid (E), preferably from 1 Department ethyl-3- methylimidazolium cation and bis (fluoromethyl sulfonylurea) imide anion ^{_{((FSO 2) 2 N -}} ) ion composed of Liquid (manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd., trade name: Elexcel AS-110), 4-methyl-1-octyl-pyridinium cation and bis (fluorosulfonyl) imine anion ((FSO ₂ ) ₂ N ^-) ionic liquid (Daiichi Kogyo Seiyaku (shares), trade name consisting of: Elexcel aS-804). As the ionic liquid (E), an adhesive composition containing the above-mentioned AS-110 and AS-804 is preferable because it has excellent antistatic properties.

The ionic liquid (E) contained in the adhesive composition is 0.5 to 5 parts by mass based on 100 parts by mass of the total amount of the (meth) acrylic resin (A) and the polyfunctional epoxy (meth) acrylate (B). Mass parts are preferred, 0.5 to 3.5 parts by mass are more preferred, and 1 to 3 parts by mass are even more preferred. If the content of the ionic liquid (E) is 0.5 parts by mass or more with respect to 100 parts by mass of the total amount described above, better antistatic performance can be obtained. As a result, an adhesive sheet having an adhesive layer containing an adhesive composition is preferably one having a sufficiently low surface resistance value. If the content of the ionic liquid (E) is 5 parts by mass or less, when an adhesive sheet having an adhesive layer containing an adhesive composition is attached to the adherend and peeled off, it becomes difficult to cause an ionic liquid. From pollution.

(Manufacturing method of ionic liquid (E)) The osmium ionic liquid (E) can use a commercial item as mentioned above, and it can also synthesize | combine by the manufacturing method shown below. As a method for synthesizing the ionic liquid (E), any target ionic liquid may be obtained, and the method is not particularly limited. For example, as a manufacturing method of the ionic liquid (E), the halide method and the hydroxide described in the document "Ionic liquids-the first line of development and the future-" [issued by CMC Publishing Co., Ltd.] can be used Physical method, acid method, complex formation method and neutralization method.

[Other components] 依据 The adhesive composition of this embodiment may contain the (meth) acrylic resin (A), the polyfunctional epoxy (meth) acrylate (B), and the hardener (C) as required. ) And other components other than the photopolymerization initiator (D) and the ionic liquid (E).其他 As other components, a tackifier, a solvent, various additives, etc. can be mentioned, and can be used in arbitrary amounts as needed.

(Tackifier) As the tackifier, conventionally known ones can be used without particular limitation. Examples of the tackifier include terpene-based tackifier resins, phenol-based tackifier resins, rosin-based tackifier resins, aliphatic petroleum resins, aromatic petroleum resins, copolymerized petroleum resins, and alicyclics. Family petroleum resin, xylene resin, epoxy-based tackifying resin, polyamide-based tackifying resin, ketone-based tackifying resin, elastic system tackifying resin, etc. These thickeners can be used alone or in combination of two or more. It is also possible to use a thickener other than these thickeners.

When the adhesive composition of this embodiment contains a tackifier, its content is preferably 30 parts by mass or less relative to 100 parts by mass of the (meth) acrylic resin (A), and 5 to 20 parts by mass Better.

(Solvent) The solvent is used for diluting the adhesive composition for the purpose of adjusting the viscosity of the adhesive composition when the adhesive composition is applied. Examples of the solvent system include methyl ethyl ketone, methyl isobutyl ketone, acetone, ethyl acetate, n-propyl acetate, tetrahydrofuran, dioxane, cyclohexanone, n-hexane, toluene, and dioxane. Organic solvents such as toluene, n-propanol, and isopropanol. These solvents may be used alone or in combination of two or more. In addition, an organic solvent other than these organic solvents may be used.

(Additives) As additive systems, for example, plasticizers, surface lubricants, leveling agents, softeners, antioxidants, anti-aging agents, light stabilizers, ultraviolet absorbers, polymerization inhibitors, benzotriazoles, etc. Light stabilizers, phosphate esters, and other antistatic agents such as flame retardants and surfactants.

[Manufacturing Method of Adhesive Composition] The adhesive composition of this embodiment can be produced by a conventionally known method. For example, the (meth) acrylic resin (A) and the polyfunctional epoxy (meth) acrylate (B), the hardener (C), the photopolymerization initiator (D), and the ion The liquid (E) and, if necessary, a thickener, a solvent, and various additives are produced by mixing and stirring using a conventionally known method.

[Adhesive sheet] The adhesive sheet of this embodiment has a sheet-like substrate and an adhesive layer formed on the substrate. It is preferable that the surface of the adhesive layer on the side opposite to the substrate is provided with a release sheet (separator). When a release sheet is provided on the adhesive layer, the adhesive layer can be protected by the release sheet until use. In the case where a release sheet is provided on the adhesive layer, the operation of peeling off the release sheet to expose the adhesive layer and crimping the adhesive layer (adhesive surface) to the adherend can be performed efficiently.之 The adhesive sheet of this embodiment can also be used as an adhesive tape that is formed according to the shape of the adherend by a rotary die method or the like. Moreover, the adhesive sheet of this embodiment can also be used as an adhesive tape by winding and cutting.

As the substrate, a known sheet-like material can be appropriately selected and used. As the base material, a resin sheet made of a transparent resin material is preferably used. Examples of the resin material include polyolefins such as polyethylene (PE) and polypropylene (PP); polyethylene terephthalate (PET), polyethylene terephthalate (PBT), and polynaphthalene Polyester flakes such as ethylene diformate; polyvinyl chloride (PVC); polyimide (PI); polyphenylene sulfide (PPS); ethylene vinyl acetate (EVA); polytetrafluoroethylene (PTFE), etc. . Among these resin materials, PE, PP, and PET are preferably used because a sheet having a moderate flexibility can be obtained. The resin material can be used alone or in combination of two or more.

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

The thickness of the substrate can be appropriately selected depending on the application of the adhesive sheet, the material of the substrate, and the like. The adhesive sheet is used to protect the wafer during the dicing step of the wafer. When a resin sheet is used as the substrate, the thickness of the substrate is, for example, 10 to 1000 μm, more preferably 30 to 600 μm, and even more preferably 50 to 300 μm. When the thickness of the substrate is 10 μm or more, the rigidity (toughness) of the adhesive sheet becomes high. Therefore, when the adhesive sheet is attached to an adherend of a wafer or the like or peeled from the adherend, there is a tendency that wrinkles or bumps do not easily occur on the adhesive sheet. Moreover, when the thickness of a base material is 10 micrometers or more, it will become easy to peel the adhesive sheet attached to an adherend from an adherend, and workability | operativity (operability, handling) will become favorable. When the thickness of the base material exceeds 1000 μm, the rigidity (toughness) of the adhesive sheet becomes too high, and in this case, workability also decreases.

On the surface that is in contact with the adhesive layer of the substrate, a surface treatment may also be performed in order to improve the adhesion between the substrate and the adhesive layer. Examples of the surface treatment include corona discharge treatment, acid treatment, ultraviolet irradiation treatment, plasma treatment, primer (primer) coating, and the like.

When a resin sheet is used as a base material, a conventionally known general sheet forming method (for example, extrusion molding, T-die molding, inflation molding, or uniaxial or biaxial stretching, etc.) can be suitably used to manufacture the substrate.

The adhesive layer having an adhesive sheet in this embodiment includes the above-mentioned adhesive composition. The thickness of the gadolinium adhesive layer is preferably 1 to 100 μm, more preferably 2 to 80 μm, and even more preferably 5 to 50 μm. When the thickness of the adhesive layer is 1 μm or more, the thickness uniformity of the adhesive is improved. On the other hand, if the thickness of the adhesive layer is 100 μm or less, even if the adhesive layer is formed using a solvent, the solvent can be easily removed, which is preferable.

When a release sheet is provided on the surface of the adhesive layer on the side opposite to the substrate, a known sheet-like or sheet-like material can be appropriately selected and used as the release sheet. As the release sheet, the above-mentioned resin sheet used as a base material is preferably used.

The thickness of the release sheet can be appropriately selected according to the application of the adhesive sheet, the material of the release sheet, and the like. When a resin sheet is used as the release sheet, the thickness of the release sheet is, for example, preferably 5 to 300 μm, more preferably 10 to 200 μm, and still more preferably 25 to 100 μm.

On the release surface (the surface in contact with the adhesive layer) of the release sheet, a release agent such as a conventionally known silicone-based, long-chain alkyl-based, or fluorine-based release agent may be used as needed to perform the release treatment.

[Manufacturing Method of Adhesive Sheet] 之 The adhesive sheet of this embodiment can be produced, for example, by the method shown below. First, an adhesive solution is prepared by dissolving or dispersing the above-mentioned adhesive composition in a solvent. The above-mentioned adhesive composition can also be used directly as an adhesive solution. Next, an adhesive solution is coated on the substrate, dried by heating, and an adhesive layer is formed. After that, the release sheet was laminated on the adhesive layer to obtain it. Furthermore, as another method for manufacturing the adhesive sheet according to this embodiment, the above-mentioned adhesive solution is applied to a release sheet, followed by heating and drying to form an adhesive layer. After that, a method of arranging a release sheet having an adhesive layer on a substrate, with the side of the adhesive layer side facing the substrate, and transferring (transferring) the adhesive layer on the substrate can be mentioned.

As a method for applying the above-mentioned adhesive solution to a substrate (or a release sheet), a known method can be used. Specifically, a conventional coater is used, and examples thereof include a gravure roll coater, a reverse roll coater, a touch roll coater, a dip roll coater, a rod coater, a blade coater, a spray coater, A coating method such as a corner coater, a direct coater, and the like.

[Application of Adhesive Sheet] 之 The adhesive sheet of this embodiment is suitable for the purpose of peeling after being attached to an adherend. In particular, it is suitable for protecting the use of the wafer when the dicing step of the wafer is performed. In this case, before performing the dicing step, an adhesive sheet is attached to a wafer on which a plurality of parts are formed. Next, the wafer is cut and diced into individual parts (dicing is performed) as element dice (wafers). Then, the adhesive sheet attached to each element small piece is irradiated with ultraviolet rays (UV). Thereby, through the substrate of the adhesive sheet, UV is irradiated to the adhesive layer, and the polyfunctional epoxy (meth) acrylate (B) in the adhesive forms a three-dimensional crosslinked structure and is hardened. As a result, the adhesive force of the adhesive layer is reduced. After that, the adhesive sheet is peeled from each element chip.

Examples of the light source used for UV irradiation of the adhesive sheet after being adhered to the adherend and before peeling include, for example, high-pressure mercury lamp, ultra-high-pressure mercury lamp, carbon arc lamp, xenon lamp, metal halide lamp, chemical Lights, fluorescent lights, etc. The amount of UV irradiation on the adhesive sheet is preferably 50 to 3000 mJ / cm ² , and more preferably 100 to 600 mJ / cm ² . If the amount of UV irradiation on the adhesive sheet is 50 mJ / cm ² or more, the UV-radiation will not only harden the adhesive layer at a sufficiently fast rate, but also the adhesive force of the adhesive layer after UV irradiation will be sufficiently small, so Better. However, even if the amount of UV irradiation applied to the adhesive sheet is 3000 mJ / cm ² or more, the corresponding effect cannot be produced.

The adhesive composition system of this embodiment includes a (meth) acrylic resin (A), a polyfunctional epoxy (meth) acrylate (B), a hardener (C), a photopolymerization initiator (D), and Ionic liquid (E). In the adhesive composition of this embodiment, the (meth) acrylic resin (A) contains a (meth) acrylic monomer (a-1) having an SP value of 9.50 (cal / cm ³ ) or more from ^0.5 . 1 to 5 mol% of the constituents and 95 to 99 mol% of the constituents including a (meth) acrylic monomer (a-2) derived from an SP value of less than 9.50 (cal / cm ³ ) ^0.5 Copolymer, and the polyfunctional epoxy (meth) acrylate (B) is a compound represented by formula (1), so it can form a sufficiently high adhesive force before UV irradiation, and an adhesive force and surface resistance value after UV irradiation Low adhesive layer.

Since the adhesive sheet of this embodiment has an adhesive layer containing the adhesive composition of this embodiment formed on a sheet-shaped substrate, peeling and charging can be effectively suppressed. In more detail, the adhesive sheet of this embodiment is made to have a sufficiently small adhesive force by applying UV irradiation to the adhesive sheet after being adhered to the adherend and before peeling. Moreover, since the adhesive layer of the adhesive sheet of this embodiment contains the ionic liquid (E) which has a high ionic conductivity, its surface resistance value is low. From this point of view, even if the adhesive sheet of this embodiment is subjected to UV irradiation to increase the elastic modulus, peeling can be easily performed while suppressing peeling and charging. In addition, even if the content of the ionic liquid (E) in the adhesive composition is small, it exhibits sufficient antistatic properties. Therefore, the influence of the ionic liquid (E) on the physical properties of the adhesive composition can be minimized. [Example]

Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. The present invention is not limited to the following examples. In the following description, "%" and "part" are based on quality unless otherwise stated. The solid content and glass transition temperature of the (meth) acrylic resins (A-1) to (A-4) produced in Production Examples 1 to 4 below were measured by the following methods. The (meth) acrylic resins (A-1) to (A-4) produced in Production Examples 1 to 4 and the polyfunctional epoxy (meth) acrylate (B- 1) The weight average molecular weight of (B-2) is measured by the following method.

<Solid content> The produced (meth) acrylic resins (A-1) to (A-4) were weighed 2 g, and dried at 110 ° C for 5 hours, and then weighed again to Based on the mass before drying and the mass after drying, it was obtained from the following formula. In addition, all solid components in the (meth) acrylic resins (A-1) to (A-4) are considered to be copolymers. Solid content (%) = [A / B] × 100 A: mass after drying B: mass before drying

<Glass transition temperature> 测定 Measured using a differential scanning calorimeter (manufactured by Hitachi High-Tech Science Corporation, DSC7000X). Specifically, 10 mg of each sample was extracted from (meth) acrylic resins (A-1) to (A-4). Then, using a differential scanning calorimeter (DSC), the temperature of the sample was changed from -80 ° C to 200 ° C at a heating rate of 10 ° C / min, and a differential scanning calorimetry was performed to determine the effect of the glass transition The endothermic start temperature was taken as (Tg). When two Tgs are observed, the average of the two Tgs is taken.

<Weight-average molecular weight> Measured at normal temperature under the following conditions using a gel permeation chromatography (manufactured by Showa Denko Corporation, Shodex (registered trademark) GPC-101) and calculated in terms of polystyrene. Column: Showa Denko Corporation, Shodex (registered trademark) LF-804 Column temperature: 40 ° C Sample: (meth) acrylic resin (A-1) to (A-4) or polyfunctional ring manufactured Oxy (meth) acrylate (B-1) (B-2) 0.2% by mass of tetrahydrofuran solution Flow rate: 1 ml / min Eluent: tetrahydrofuran

Production Example 1 <(meth) acrylic resin (A-1)> In a reaction apparatus equipped with a stirrer, a temperature regulator, a reflux condenser, a dropping funnel, and a thermometer, 251.7 parts of butyl acrylate and ethacrylic acid were charged. 76.7 parts of ester, 17.2 parts of methyl methacrylate, 2.8 parts of acrylic acid, 1.8 parts of 2-hydroxyethyl acrylate and 645 parts of ethyl acetate as a solvent. After starting heating and refluxing, 0.1 part of azobisisobutyronitrile as a polymerization initiator was added, and the reaction was carried out at the reflux temperature of ethyl acetate for 3 hours. Thereafter, 0.1 part of azobisisobutyronitrile was added to dissolve 5 parts of ethyl acetate in the latter, and the reaction was further performed at the reflux temperature for 4 hours. Thus, a (meth) acrylic resin (A-1) having a solid content of 35%, a weight average molecular weight of 650,000, and a glass transition temperature of -40 ° C was obtained.

Production Example 2 <(meth) acrylic resin (A-2)> In a reaction apparatus equipped with a stirrer, a temperature regulator, a reflux condenser, a dropping funnel, and a thermometer, 246.4 parts of butyl acrylate and ethacrylic acid were charged. 76.7 parts of ester, 17.2 parts of methyl methacrylate, 2.8 parts of acrylic acid, 7.0 parts of 2-hydroxyethyl acrylate and 645 parts of ethyl acetate as a solvent. After the reflux was started, 0.1 part of azobisisobutyronitrile as a polymerization initiator was added, and the reaction was allowed to proceed at the reflux temperature of ethyl acetate for 3 hours. Thereafter, 0.1 part of azobisisobutyronitrile was added to dissolve 5 parts of ethyl acetate in the latter, and the reaction was further performed at the reflux temperature for 4 hours. Thus, a (meth) acrylic resin (A-2) having a solid content of 35%, a weight average molecular weight of 670,000, and a glass transition temperature of -40 ° C was obtained.

Production Example 3 <(meth) acrylic resin (A-3)> 350.5 parts of butyl acrylate and methacrylic acid were placed in a reaction apparatus equipped with a stirrer, a temperature regulator, a reflux condenser, a dropping funnel, and a thermometer. 2.0 parts of ester, 39.7 parts of methacrylamide, 1.2 parts of acrylic acid, 3.9 parts of 2-hydroxyethyl acrylate and 595 parts of ethyl acetate as a solvent. After starting heating and refluxing, 0.2 parts of azobisisobutyronitrile as a polymerization initiator was added, and the reaction was carried out at the refluxing temperature of ethyl acetate for 3 hours. Thereafter, 0.4 part of azobisisobutyronitrile was added to dissolve 5 parts of ethyl acetate in the latter, and the reaction was further performed at the reflux temperature for 4 hours. Thus, a (meth) acrylic resin (A-3) having a solid content of 40%, a weight average molecular weight of 580,000, and a glass transition temperature of -41 ° C was obtained.

Production Example 4 <(meth) acrylic resin (A-4)> 207.0 parts of butyl acrylate and methacrylic acid were placed in a reaction apparatus equipped with a stirrer, a temperature regulator, a reflux condenser, a dropping funnel, and a thermometer. 103.1 parts of esters, 34.9 parts of methacrylamide, 1.0 parts of acrylic acid, 3.3 parts of 2-hydroxyethyl acrylate and 645 parts of ethyl acetate as a solvent. After starting heating and refluxing, 0.2 parts of azobisisobutyronitrile as a polymerization initiator was added, and the reaction was carried out at the refluxing temperature of ethyl acetate for 3 hours. Thereafter, 0.4 part of azobisisobutyronitrile was added to dissolve 5 parts of ethyl acetate in the latter, and the reaction was further performed at the reflux temperature for 4 hours. Thereby, a (meth) acrylic resin (A-4) having a solid content of 35%, a weight average molecular weight of 550,000, and a glass transition temperature of -25 ° C was obtained.

Table 1 shows the monomers used in the (meth) acrylic resins (A-1) to (A-4) produced in Production Examples 1 to 4. The composition ratio of the monomer components in Table 1 is the ratio of each monomer in the total of the (meth) acrylic monomer (a-1) and the (meth) acrylic monomer (a-2) (mol%). ).

Production Example 5 <Polyfunctional epoxy (meth) acrylate (B-1)> 投入 The bisphenol A epoxy resin was placed in a reaction device with a stirrer, a temperature regulator, a reflux condenser, a dropping funnel, and a thermometer. (Made by Asahi Kasei Corporation, trade name; ARALDITE (registered trademark) AER2603, epoxy equivalent 189) 100 parts, 38 parts acrylic acid, 0.6 parts triphenylphosphine as a catalyst, and methyl hydroquinone as a polymerization inhibitor 0.12 servings. While blowing air into the reaction device, the reaction was continued at 120 ° C for 8 hours to obtain a reactant containing an epoxy (meth) acrylate having an acid value of 0.5 KOHmg / g.

Next, the temperature of the reactant was lowered to 60 ° C, and 49 parts of 2-isocyanatoethyl methacrylate (manufactured by Showa Denko Corporation, trade name; Karenz MOI (registered trademark)) were mixed with an amine through a dropping funnel. A mixed solution of 0.02 parts of dibutyltin dilaurate of the carbamate-forming catalyst was dropped. After completion of the dropping, the reaction system was kept at 70 ° C. for 4 hours to disappear the isocyanate group. Through the above steps, a polyfunctional epoxy (meth) acrylate (B-1) having a weight average molecular weight of 1,300 was obtained.

Polyfunctional epoxy (meth) acrylate (B-1) (1) Department of formula ¹ in which R is a hydrogen atom, the formula (1) of X in the formula (2) represented by the group. In addition, 60% of the total of R ² and R ³ in the formula (1) is an acrylfluorenyl group, and 40% is a hydrogen atom. R ⁴ in formula (2) is a methyl group. N in Formula (1) is 1-2. The proportion of acrylfluorenyl groups and the proportion of hydrogen atoms in the above totals are defined by ¹ H-NMR.

Production Example 6 <Polyfunctional epoxy (meth) acrylate (B-2)> A hydrogenated bisphenol A epoxy resin was charged into a reaction device including a stirrer, a temperature regulator, a reflux condenser, a dropping funnel, and a thermometer. 100 parts of resin (made by Nippon Steel Chemical Co., Ltd .; trade name; ST-3000, epoxy equivalent 230), 31 parts of acrylic acid, 0.4 parts of triphenylphosphine, and 0.08 parts of methyl hydroquinone. While blowing air into the reaction device, the reaction was continued at 120 ° C for 8 hours to obtain a reactant containing an epoxy (meth) acrylate having an acid value of 0.5 KOHmg / g.

Next, the temperature of the reactant was lowered to 60 ° C., and 45 parts of ethyl 2-isocyanate methacrylate (manufactured by Showa Denko Corporation, trade name; Karenz MOI (registered trademark)) and amine were dropped through a dropping funnel. A mixed solution of 0.02 parts of dibutyltin dilaurate of the carbamate-forming catalyst was dropped. After completion of the dropping, the reaction system was kept at 70 ° C. for 4 hours to disappear the isocyanate group. Through the above steps, a polyfunctional epoxy (meth) acrylate (B-2) having a weight average molecular weight of 1,400 was obtained.

Polyfunctional epoxy (meth) acrylate (B-2) R (1 ) is based Formula ¹ is a hydrogen atom, the formula (1) in the group X is represented by the formula (3). In addition, 60% of the total of R ² and R ³ in the formula (1) is an acrylfluorenyl group, and 40% is a hydrogen atom. R ⁵ in formula (3) is a methyl group. N in Formula (1) is 1-2. The proportion of acrylfluorenyl groups and the proportion of hydrogen atoms in the above totals are defined by ¹ H-NMR.

(Example 1) <Production of Adhesive Composition> In a room where the active line was shielded, 142.9 parts of (meth) acrylic resin (A-1) and polyfunctional epoxy (meth) acrylic acid were added to a plastic container. 50.0 parts of ester (B-1), 45% ethyl acetate solution of toluene diisocyanate adduct of trimethylolpropane as a hardener (manufactured by Japan Polyurethane Industry Co., Ltd., CORONATE (registered trademark) L-45E) 2.0 parts, 2,4,6-trimethylbenzyl-diphenyl-phosphine oxide (L-TPO, manufactured by BASF, 2.0 parts) as a photopolymerization initiator, 1-ethyl -3-methyl imidazolium cation and a bis (fluoromethyl sulfonylurea) imide anion ^{_{((FSO 2) 2 N -}} ) constituting the ionic liquid (ichi Kogyo Seiyaku Co., Ltd .; trade name; Elexcel aS-110) 1.5 parts and stir as an adhesive composition.

＜ Production of adhesive sheet ＞ The obtained adhesive composition was applied to a polyethylene terephthalate (PET) sheet having a thickness of 50 μm, and the film thickness was 20 μm after drying, and then heated and dried at 105 ° C. for 2 minutes. To form an adhesive layer. After that, a release sheet composed of a PET sheet was laminated on the adhesive layer to obtain an adhesive sheet.

(Examples 2 to 9 and Comparative Examples 1 to 2) Except the materials and contents of (meth) acrylic resin (A), polyfunctional epoxy (meth) acrylate (B), and ionic liquid (E), such as An adhesive sheet was produced in the same manner as in Example 1 except that the description was changed in Table 2.

(Comparative Example 3) Instead of using a bisphenol A epoxy acrylate (manufactured by Showa Denko Corporation, trade name; VR-77) instead of a polyfunctional epoxy (meth) acrylate (B-1), Example 1 produced an adhesive sheet in the same manner.

(Comparative Example 4) Instead of using trimethylolpropane triacrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd .; trade name; Viscoat # 295) instead of the polyfunctional epoxy (meth) acrylate (B-1), An adhesive sheet was produced in the same manner as in Example 1.

(Comparative Example 5) 黏 An adhesive sheet was produced in the same manner as in Example 1 except that it did not contain an ionic liquid.

Tables 2 and 3 show materials and contents used in the adhesive composition in Examples 1 to 9 and Comparative Examples 1 to 5. The numerical value of the (meth) acrylic resin (A) is the amount of (meth) acrylic resins (A-1) to (A-4) used in Production Examples 1 to 4. The numerical values in parentheses (A-1) to (A-4) refer to the amount (parts by mass) of the solid content. The numerical value of the polyfunctional epoxy (meth) acrylate (B) is the polyfunctionality in the total amount of the solid content of the (meth) acrylic resin (A) and the polyfunctional epoxy (meth) acrylate (B). Content (mass%) of an epoxy (meth) acrylate (B). The numerical values of the contents of the hardener (C), the photopolymerization initiator (D), and the ionic liquid (E) are each relative to the solid content of the (meth) acrylic resin (A) and the polyfunctional epoxy (methyl ) Content (mass part) of 100 parts by mass of the total of the acrylate (B).

Next, the adhesive sheets of Examples 1 to 9 and Comparative Examples 1 to 5 were evaluated for their adhesion to the glass plate before and after UV curing, surface resistivity, and peeling chargeability by the methods described below. The results are shown in Tables 2 and 3.

(Measurement of Adhesive Force) The adhesive sheet was cut into a size of 25 mm in length and 100 mm in width, and the release sheet was peeled to expose the adhesive layer. Next, the exposed adhesive layer (measurement surface) was brought into contact with the glass plate, and the adhesive sheet was attached to the glass plate, and a 2 kg rubber roller (width: about 50 mm) was reciprocated back and forth once as a sample before UV irradiation. . In addition, UV irradiation was performed on a sample before UV irradiation using a conveyor-belt type ultraviolet irradiation device (manufactured by EYE GRAPHICS CO., LTD., 2KW lamp, 80W / cm) at a UV irradiation amount of 500 mJ / cm ² as UV irradiation. After the sample.

The samples before UV irradiation and the samples after UV irradiation were left in an environment of 23 ° C. and 50% humidity for 24 hours, and then subjected to a 180 ° direction tensile test at a peeling speed of 300 mm / minute based on JIS Z0237 to measure adhesion. Force (N / 25mm). The obtained measured value was used as the adhesive force.

(Evaluation of Residual Adhesive) With respect to the sample after UV irradiation, it was visually confirmed whether or not an adhesive agent remained on the glass plate after the adhesion measurement, and the evaluation was performed on the following basis. The results are shown in Tables 2 and 3. Evaluation Criteria ○: The adhesive did not remain on the adherend. ×: The adhesive remained on the adherend.

(Evaluation of peeling chargeability (measurement of surface resistivity)) The adhesive sheet was cut into a size of 120 mm and 120 mm in width, and the release sheet was peeled to expose the adhesive layer. Next, a high-resistivity meter (Mitsubishi Chemical Analytech Co., Ltd.) was used for the pressure-sensitive adhesive sheet with the pressure-sensitive adhesive layer exposed at a temperature of 23 ° C and a relative humidity (RH) of 50% at a voltage of 500 V × 60 seconds (Manufactured, Hiresta-UX), and measured the surface resistivity of the adhesive layer side. Then, evaluation was performed based on the following criteria. The results are shown in Tables 2 and 3.

Evaluation Criteria ◎: Surface resistivity is less than 1 × 10 ¹² Ω / □ ○: Surface resistivity is 1 × 10 ¹² Ω / □ or more and less than 5 × 10 ¹² Ω / □ △: Surface resistivity is 5 × 10 ¹² Ω / □ or more and less than 1 × 10 ¹³ Ω / □ ×: Surface resistivity is 1 × 10 ¹³ Ω / □ or more

As shown in Table 2, the adhesive sheets of Examples 1 to 9 had an adhesive force of 10 (N / 25 mm) or more before UV irradiation and a high adhesive force. In addition, the adhesive sheets of Examples 1 to 9 had an adhesive force after UV irradiation of 0.15 (N / 25mm) or less, a low adhesive force, and an evaluation of residual adhesive was "○". In addition, the adhesive sheets of Examples 1 to 9 had a low surface resistivity of less than 5 × 10 ¹² Ω / □, and the peeling chargeability was "○" or "◎".

On the other hand, as shown in Table 3, the use amount of the (meth) acrylic monomer (a-1) is large, and the use amount of the (meth) acrylic monomer (a-2) is small (a Base) The adhesive sheet of Comparative Example 1 and Comparative Example 2 of the adhesive layer of the adhesive composition of the acrylic resin (A-3) (A-4) has a high surface resistivity and a peeling chargeability of "×".

A bisphenol A ring having a polyfunctional epoxy (meth) acrylate (B) which does not contain a compound represented by the formula (1) and which contains R ² and R ³ in the formula (1) as hydrogen atoms The adhesive sheet of the adhesive layer of the oxyacrylate adhesive composition of Comparative Example 3 had high adhesion after UV irradiation, and the evaluation of the residual adhesive was “×”. The adhesive sheet of Comparative Example 4 having an adhesive layer using an adhesive composition that does not contain the compound represented by formula (1) has an adhesive force of less than 10 (N / 25mm) before UV irradiation and Low adhesion. In addition, the adhesive force after UV irradiation was also high, and the evaluation of the residue was "×". The adhesive sheet of Comparative Example 5 having an adhesive layer using an adhesive composition not containing an ionic liquid (E) had a high surface resistivity and a peeling chargeability of “×”. [Industrial availability]

In the conventional adhesive sheet, peeling and charging may not be sufficiently suppressed. Therefore, there is a demand for an adhesive sheet that can more effectively suppress peeling and charging. The present invention has been made in view of the foregoing facts, and can provide an adhesive composition that can form an adhesive layer with sufficiently high adhesive force before UV irradiation and low adhesive force and surface resistance after UV irradiation. The present invention can provide an adhesive layer having sufficiently high adhesive force before UV irradiation, low adhesive force after UV irradiation, and low surface resistance value, and can effectively suppress peeling and charging of an adhesive sheet.

Claims (9)

An adhesive composition comprising a (meth) acrylic resin (A), a polyfunctional epoxy (meth) acrylate (B), a hardener (C), and a photopolymerization initiator ( D) and ionic liquid (E), the (meth) acrylic resin (A) contains a (meth) acrylic monomer (a-1) derived from an SP value of 9.50 (cal / cm ³ ) ^0.5 or more 1 to 5 mol% of the constituents and 95 to 99 mol% of the constituents including a (meth) acrylic monomer (a-2) derived from an SP value of less than 9.50 (cal / cm ³ ) ^0.5 Copolymer, the aforementioned polyfunctional epoxy (meth) acrylate (B) is a compound represented by the following formula (1): (In formula (1), R ¹ is a hydrogen atom or a methyl group, which may be the same or different, respectively; R ² is a hydrogen atom or a group having an ethylenically unsaturated bond; R ³ is a hydrogen atom or a group having an ethylenically unsaturated bond R ³ has at least one ethylenically unsaturated bond when n is 1 and R ² is a hydrogen atom; when R ³ is n or more and R ² is a hydrogen atom, plural R ³ A part or all of R ³ has at least one ethylenically unsaturated bond; X is a base having a ring structure; n is a positive integer). The adhesive composition according to claim 1, wherein X in the formula (1) is a base represented by the formula (2), (In formula (2), R ⁴ is a hydrogen atom or a methyl group, and may be the same or different, respectively). The adhesive composition according to claim 1, wherein X in the formula (1) is a base represented by the formula (3), (In formula (3), R ⁵ is a hydrogen atom or a methyl group, and may be the same or different, respectively). The adhesive composition according to claim 1, wherein the ionic liquid (E) includes: 1-ethyl-3-methylimidazolium cation and a bis (fluorosulfonyl) imide anion ((FSO ₂ ) ₂ N ^-) and the ionic liquid comprises methyl-1-octyl - pyridinium cations and bis (fluoromethyl sulfonylurea) imide anion ^{_{((FSO 2) 2 N -}} ) of the ionic liquid in at least either of . The adhesive composition according to claim 1, wherein the polyfunctional epoxy (in the total amount of the (meth) acrylic resin (A) and the polyfunctional epoxy (meth) acrylate (B)) The content of the meth) acrylate (B) is 10 to 70% by mass. The adhesive composition according to claim 1, wherein the adhesive composition contains 100 parts by mass of the total of the (meth) acrylic resin (A) and the multifunctional epoxy (meth) acrylate (B). The hardening agent (C) is 0.05 to 10 parts by mass. The adhesive composition according to claim 1, which contains 0.1 to 5 parts by mass of the photopolymerization initiator (D) with respect to 100 parts by mass of the polyfunctional epoxy (meth) acrylate (B). The adhesive composition according to claim 1, wherein the adhesive composition contains 100 parts by mass of the total of the (meth) acrylic resin (A) and the multifunctional epoxy (meth) acrylate (B). 0.5 to 5 parts by mass of the ionic liquid (E). An adhesive sheet comprising a sheet-like substrate and an adhesive layer formed on the substrate, and the adhesive layer includes the adhesive composition according to claim 1.