WO2016121557A1

WO2016121557A1 - Pressure-sensitive adhesive sheet, laminate for touch panel, and capacitive touch panel

Info

Publication number: WO2016121557A1
Application number: PCT/JP2016/051301
Authority: WO
Inventors: 三ツ井　哲朗
Original assignee: 富士フイルム株式会社
Priority date: 2015-01-28
Filing date: 2016-01-18
Publication date: 2016-08-04
Also published as: TW201627440A

Abstract

The purpose of the present invention is to provide: a pressure-sensitive adhesive sheet which has a high elongation at break, changes little in relative permittivity with changing temperature, and is excellent in terms of processability, applicability, and adhesiveness; and a laminate for touch panels and a capacitive touch panel which both include the pressure-sensitive adhesive sheet. The pressure-sensitive adhesive sheet according to the present invention is obtained by curing a curable composition, wherein the curable composition contains at least one plasticizer selected from the group consisting of rubbers, hydrogenated terpene resins, modified terpene resins, and hydrogenated rosin resins and further contains a crosslinking agent and wherein the gel content is 50 mass% or less and the crosslinking agent amount proportion represented by the following equation (1) is 1.00×10^-4 or less. (Crosslinking agent amount proportion)=(content of the crosslinking agent)÷(molecular weight of the crosslinking agent)×(number of crosslinking groups in the crosslinking agent)÷(gel content) (1)

Description

Adhesive sheet, laminate for touch panel, and capacitive touch panel

The present invention relates to an adhesive sheet, a laminate for a touch panel, and a capacitive touch panel.

In recent years, the rate of mounting touch panels on mobile phones, portable game devices, and the like has increased, and for example, capacitive touch panels capable of detecting multiple points (hereinafter simply referred to as touch panels) are attracting attention.
Usually, when manufacturing a touch panel, a pressure-sensitive adhesive sheet is used to bring the members such as a display device and a touch panel sensor into close contact with each other.

For example, Patent Document 1 discloses a pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive layer containing a specific acrylic polymer, wherein the pressure-sensitive adhesive layer has a gel fraction of 70 to 100% by weight. Is disclosed (claims, etc.).

JP 2013-104006 A

In recent years, touch panels are shifting from an air gap method to a direct bonding method (a method in which a touch panel sensor and a display device such as a liquid crystal display device (LCD) are directly bonded) for reasons such as improved visibility.
On the other hand, as described above, in the direct bonding method, since the touch panel sensor and the display device are directly bonded, if distortion or bubbles occur when bonded, it is difficult to rebond and the yield tends to decrease. Therefore, the pressure-sensitive adhesive sheet used for bonding has high flexibility (high elongation at break) and is less likely to cause distortion or foam after bonding (for example, one week after bonding). (Excellent aptitude (direct bonding aptitude)). At the same time, excellent workability and adhesion are also required. Furthermore, from the viewpoint of the environmental adaptability of the touch panel, it is desired that the temperature change of the relative permittivity is small under various usage environments such as a cold region and a warm region.

Under such circumstances, when the present inventor examined the pressure-sensitive adhesive sheet of Patent Document 1, the elongation at break was small, and the bonding suitability and adhesion were insufficient, which did not necessarily satisfy the level required recently. It became clear. Further, it has become clear that there are cases where the temperature change of the relative permittivity is large and does not necessarily satisfy the level required recently.

Therefore, in view of the above circumstances, the present invention aims to provide a pressure-sensitive adhesive sheet having a high elongation at break, a small change in temperature of relative permittivity, and excellent workability, bonding suitability and adhesion. To do.

As a result of earnest research to achieve the above-mentioned problems, the present inventor uses a curable composition containing a specific plasticizer and a cross-linking agent, and specifies the gel fraction and the cross-linking agent amount ratio. The inventors have found that this can be solved, and have reached the present invention.
That is, the present inventor has found that the above problem can be solved by the following configuration.

(1) A pressure-sensitive adhesive sheet obtained by curing a curable composition,
The curable composition contains at least one plasticizer selected from the group consisting of rubber, hydrogenated terpene resin, modified terpene resin and hydrogenated rosin resin, and a crosslinking agent,
The gel fraction is 50% by mass or less,
The adhesive sheet whose cross-linking agent amount ratio represented by the following formula (1) is 1.00 × 10 ⁻⁴ or less.
Crosslinking agent amount ratio = crosslinking agent content / crosslinking agent molecular weight × crosslinking agent crosslinkable group number / gel fraction (1)
Here, a crosslinking agent content rate represents content of the said crosslinking agent with respect to solid content whole quantity in the said curable composition, and a unit is the mass%. The cross-linking agent molecular weight represents the molecular weight of the cross-linking agent. The number of crosslinkable crosslinkable groups represents the number of crosslinkable groups possessed by the crosslinker. A gel fraction represents the gel fraction of the said adhesive sheet, and a unit is the mass%.
(2) The pressure-sensitive adhesive sheet according to (1), wherein the gel fraction is 10 to 30% by mass.
(3) The adhesive sheet according to (1) or (2), wherein the curable composition contains a prepolymer.
(4) The pressure-sensitive adhesive sheet according to (3), wherein the prepolymer has a weight average molecular weight of 200,000 or more.
(5) The pressure-sensitive adhesive sheet according to (3) or (4), wherein the prepolymer is formed by thermal polymerization.
(6) The pressure-sensitive adhesive sheet according to any one of the above (1) to (5), wherein the adhesion to glass is 0.2 N / mm or more.
(7) The pressure-sensitive adhesive sheet according to any one of (1) to (6), wherein the elongation at break is 700% or more.
(8) The pressure-sensitive adhesive sheet according to any one of (1) to (7), wherein the cross-linking agent has a molecular weight of 10,000 or less.
(9) The pressure-sensitive adhesive sheet according to any one of the above (1) to (8), wherein the relative dielectric constant at 25 ° C. is 3.0 or less.
(10) The pressure-sensitive adhesive sheet according to any one of the above (1) to (9), wherein the temperature change of the relative dielectric constant from 0 ° C. to 60 ° C. is 15% or less.
(11) The pressure-sensitive adhesive sheet according to (10), wherein the change in temperature of the relative dielectric constant from −40 ° C. to 80 ° C. is 15% or less.
(12) The pressure-sensitive adhesive sheet according to any one of (1) to (11), wherein the cross-linking agent amount ratio is 6.00 × 10 ⁻⁵ or more.
(13) The pressure-sensitive adhesive sheet according to any one of (1) to (12) above, which does not contain a substrate.
(14) The pressure-sensitive adhesive sheet according to any one of (1) to (13), wherein the crosslinking agent is an isocyanate-based crosslinking agent.
(15) The plasticizer according to any one of (1) to (14), wherein the plasticizer is at least one plasticizer selected from the group consisting of rubber, hydrogenated terpene resin, and modified terpene resin. Adhesive sheet.
(16) The pressure-sensitive adhesive sheet according to any one of (1) to (15) above, which is a pressure-sensitive adhesive sheet for a touch panel.
(17) A laminate for a touch panel, comprising the pressure-sensitive adhesive sheet according to (16) above and a capacitive touch panel sensor.
(18) Furthermore, a protective substrate is provided,
The laminate for a touch panel according to (17), comprising the protective substrate, the pressure-sensitive adhesive sheet, and the capacitive touch panel sensor in this order.
(19) A capacitive touch panel comprising a capacitive touch panel sensor, the adhesive sheet according to (16), and a display device in this order.

As described below, according to the present invention, it is possible to provide a pressure-sensitive adhesive sheet having a high elongation at break and excellent workability, bonding suitability and adhesion.

It is sectional drawing of the one aspect | mode of the laminated body for touchscreens of this invention. It is sectional drawing of another aspect of the laminated body for touchscreens of this invention. It is sectional drawing of the electrostatic capacitance type touch panel of this invention.

Below, the adhesive sheet of this invention, the laminated body for touchscreens provided with the said adhesive sheet, and a capacitive touch panel are demonstrated.
In this specification, (meth) acrylate represents acrylate or methacrylate, (meth) acryloyl group represents acryloyl group or methacryloyl group, and (meth) acryl represents acryl or methacryl.
In the present specification, a numerical range expressed using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.
Moreover, in this specification, when a component contains 2 or more types of compounds, content of the said component refers to total content.

[Adhesive sheet]
The pressure-sensitive adhesive sheet of the present invention is a pressure-sensitive adhesive sheet obtained by curing a curable composition. Here, the curable composition contains at least one plasticizer selected from the group consisting of rubber, hydrogenated terpene resin, modified terpene resin and hydrogenated rosin resin, and a crosslinking agent.
The pressure-sensitive adhesive sheet of the present invention has a gel fraction of 50% by mass or less and a cross-linking agent amount ratio represented by the formula (1) described later of 1.00 × 10 ⁻⁴ or less.
Since the pressure-sensitive adhesive sheet of the present invention has such a configuration, it is considered that a desired effect can be obtained. The reason is not clear, but because the gel fraction in the pressure-sensitive adhesive sheet and the number of crosslinkable groups with respect to the gel fraction are suppressed, the flexibility is high (the elongation at break is large), and the adhesiveness and adhesion are excellent. It is considered that by containing a specific plasticizer, elasticity is imparted and processability is excellent.

First, the curable composition, gel fraction, and crosslinking agent amount ratio used for the pressure-sensitive adhesive sheet of the present invention will be described in detail, and then the method for producing the pressure-sensitive adhesive sheet of the present invention will be described in detail.

(Curable composition)
The curable composition used in the present invention (hereinafter also simply referred to as curable composition) is at least one plastic selected from the group consisting of rubber, hydrogenated terpene resin, modified terpene resin and hydrogenated rosin resin. An agent (hereinafter also referred to as a specific plasticizer) and a crosslinking agent. It is preferable that the said curable composition contains the prepolymer formed by superposing | polymerizing a monomer.

<Specific plasticizer>
As described above, the curable composition used in the present invention contains at least one plasticizer (specific plasticizer) selected from the group consisting of rubber, hydrogenated terpene resin, modified terpene resin, and hydrogenated rosin resin. contains. The specific plasticizer is preferably at least one plasticizer selected from the group consisting of rubber, hydrogenated terpene resin and modified terpene resin, and at least one selected from the group consisting of hydrogenated terpene resin and modified terpene resin. More preferably, it is a seed plasticizer.

(Rubber)
The rubber is not particularly limited, for example, natural rubber, polyisobutylene, polybutadiene, hydrogenated polyisoprene, hydrogenated polybutadiene, polyisoprene, polybutene, styrene butadiene copolymer, or a combination arbitrarily selected from these groups Examples thereof include copolymers and mixtures thereof.

(Hydrogenated terpene resin)
The hydrogenated terpene resin is not particularly limited as long as it is a hydrogenated terpene resin. The terpene resin to be hydrogenated is not particularly limited, and examples thereof include aromatic modified terpene resins and terpene phenol resins.

(Modified terpene resin)
The modified terpene resin is not particularly limited as long as it is a modified terpene resin. Although it does not restrict | limit especially as a modified terpene resin, For example, an aromatic modified terpene resin etc. are mentioned.

(Hydrogenated rosin resin)
The hydrogenated rosin resin is not particularly limited as long as it is a hydrogenated rosin resin. The rosin resin to be hydrogenated is not particularly limited, and examples thereof include natural rosin resins, disproportionated rosin resins, polymerized rosin resins, and resins obtained by esterifying these.

The content of the specific plasticizer with respect to the total solid content in the curable composition is preferably 10 to 90% by mass, more preferably 20 to 80% by mass, and 40 to 60% by mass. Further preferred.
In addition, in this specification, solid content intends the component except a solvent.

<Crosslinking agent>
As described above, the curable composition used in the present invention contains a crosslinking agent.
The crosslinking agent is not particularly limited as long as it is a compound having a plurality of (two or more) crosslinkable groups.
Examples of the crosslinkable group include an isocyanate group, an epoxy group, and a radical polymerizable group (for example, (meth) acryloyl group, acrylamide group, vinyl group, styryl group, allyl group, etc.).
Examples of the crosslinking agent having an isocyanate group as a crosslinking group (isocyanate-based crosslinking agent) include tolylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate (isophorone diisocyanate), xylylene diisocyanate, hydrogenated xylylene diisocyanate, diphenylmethane diisocyanate, Examples thereof include hydrogenated diphenylmethane diisocyanate, tetramethylxylylene diisocyanate, naphthalene diisocyanate, triphenylmethane triisocyanate, polymethylene polyphenyl isocyanate, and adducts with polyols such as trimethylolpropane.
As a crosslinking agent (epoxy crosslinking agent) having an epoxy group as a crosslinking group, bisphenol A, epichlorohydrin type epoxy resin, ethylene glycol glycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, diglycidylaniline, diglycidylamine, N, N, N ′, N′-tetraglycidyl-m-xylenediamine and 1,3-bis (N , N'-diglycidylaminomethyl) cyclohexane and the like.

The molecular weight of the crosslinking agent (crosslinking agent molecular weight) is not particularly limited as long as the crosslinking agent amount ratio described below is within a specific range, but is preferably 100 to 10,000. In addition, when there exists distribution in the molecular weight of a crosslinking agent, let the molecular weight of a crosslinking agent be the weight average molecular weight (Mw) obtained by GPC (polystyrene standard).
The number of crosslinkable groups of the crosslinker (crosslinker crosslinkable group number) is not particularly limited as long as the crosslinker amount ratio described below is in a specific range, but is preferably 2 to 10.

The content of the crosslinking agent relative to the total solid content in the curable composition (crosslinking agent content) is not particularly limited as long as the crosslinking agent content ratio described below is in a specific range, but is 0.01 to 2.0% by mass. It is preferable that the content is 0.1 to 0.8 mass.

<Monomer>
The curable composition used in the present invention may contain a monomer.
The monomer is not particularly limited as long as it is a polymerizable compound (polymerizable group-containing compound).
The polymerizable group is not particularly limited, and examples thereof include a radical polymerizable group and a cationic polymerizable group. Of these, a radical polymerizable group is preferable from the viewpoint of reactivity. Examples of the radical polymerizable group include (meth) acryloyl group, itaconic acid ester group, crotonic acid ester group, isocrotonic acid ester group, maleic acid ester group, vinyl group, acrylamide group, (meth) acrylamide group and the like. . Of these, a (meth) acryloyl group, a vinyl group, an acrylamide group, and a (meth) acrylamide group are preferable, and a (meth) acryloyl group is particularly preferable.
The monomer is preferably a compound having only one polymerizable group.

The monomer is preferably a (meth) acrylic monomer or a vinyl monomer (for example, vinyl acetate, vinyl chloride, styrene, etc.), and more preferably a (meth) acrylic monomer.

The (meth) acrylic monomer is not particularly limited. For example, (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) ) Acrylate, cyclohexyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, 2-ethylhexyl (meth) acrylate, dodecyl (meth) acrylate, isononyl (meth) acrylate, isodecinyl (meth) acrylate, stearyl (meth) acrylate, 2 -Hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, isobornyl (meth) acrylate, butoxydiethylene group Cole (meth) acrylate, benzyl (meth) acrylate, dicyclohexyl (meth) acrylate, 2-dicyclohexyloxyethyl (meth) acrylate, morpholino (meth) acrylamide, phenoxyethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, ethylene Glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, Nonanediol di (meth) acrylate, tris (2- (meth) acryloyloxyethyl) isocyanurate, 2-morpholinoethyl (meth) acrylate, 9-anthryl (meth) acrylate 2,2-bis (4- (meth) acryloyloxyphenyl) propane, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, trans-1,4-cyclohexanediol di (meth) acrylate, And dicyclopentenyloxyethyl methacrylate.

Although the content of the monomer with respect to the total solid content in the curable composition is not particularly limited, it is preferably less, preferably 5% by mass or less, and more preferably 1% by mass or less.

<Prepolymer>
As described above, the curable composition used in the present invention preferably contains a prepolymer. The prepolymer is formed by polymerizing monomers, and can be polymerized with other monomers and prepolymers. Specific examples and preferred embodiments of the monomer are as described above.
The method for forming the prepolymer is not particularly limited, and examples thereof include photopolymerization and thermal polymerization. More specifically, for example, polymerization in a solution in which a monomer, a photopolymerization initiator or a thermal polymerization initiator, and a solvent are mixed may be mentioned. The formation method of the prepolymer is preferably thermal polymerization.
The weight average molecular weight of the prepolymer is not particularly limited, but is preferably 200,000 or more, and more preferably 400,000 or more. The upper limit is not particularly limited, but is preferably 2 million or less.
In the present specification, the weight average molecular weight (Mw) is measured in terms of standard polystyrene by gel permeation chromatography (GPC) using tetrahydrofuran as a solvent.

The content of the prepolymer relative to the total solid content in the curable composition is not particularly limited, but is preferably 10 to 90% by mass, more preferably 20 to 80% by mass, and 40 to 60% by mass. More preferably it is.

<Initiator>
The curable composition used in the present invention preferably contains an initiator.
The initiator is not particularly limited, and examples thereof include an azo polymerization initiator, a persulfate polymerization initiator, a persulfate polymerization initiator, and a redox polymerization initiator.
Examples of the azo polymerization initiator include 2,2′-azobisisobutyronitrile, 2,2′-azobis (2-amidinopropane) dihydrochloride, 2,2′-azobis [2- (5- Methyl-2-imidazolin-2-yl) propane] dihydrochloride, 2,2′-azobis (2-methylpropionamidine) disulfate, 2,2′-azobis (N, N′-dimethyleneisobutylamidine) dihydro Examples include chloride.
Examples of the persulfate-based polymerization initiator include potassium persulfate and ammonium persulfate.
Examples of the persulfate-based polymerization initiator include benzoyl peroxide, t-butyl hydroperoxide, and hydrogen peroxide.
Examples of the redox polymerization initiator include redox initiators that are a combination of a peroxide and a reducing agent, such as a combination of a persulfate and sodium bisulfite, or a combination of a peroxide and sodium ascorbate. It is done.
Such a polymerization initiator may be a water-soluble initiator or an oil-soluble initiator. Moreover, such a polymerization initiator may be used individually or in combination of 2 or more types.

Examples of the initiator include an alkynephenone photopolymerization initiator, a methoxyketone photopolymerization initiator, an acyl phosphine oxide photopolymerization initiator, and a hydroxyketone photopolymerization initiator (for example, IRGACURE184; 1,2-α -Hydroxyalkylphenone), aminoketone photoinitiators (for example, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one (IRGACURE® 907), oxime type A photoinitiator etc. are also mentioned.

As a suitable aspect of an initiator, the aspect containing at least 1 selected from the group which consists of a monoacyl phosphine oxide (A1) and a bisacyl phosphine oxide (A2) is mentioned.
The monoacylphosphine oxide (A1) is not particularly limited, and a known monoacylphosphine oxide can be used. As a suitable aspect of monoacylphosphine oxide (A1), the monoacylphosphine oxide represented by a following formula (A1) is mentioned, for example.

In the above formula (A1), R ^A11 represents a hydrocarbon group which may have a substituent. Although it does not restrict | limit especially as a hydrocarbon group, As an example, an aliphatic hydrocarbon group, an aromatic hydrocarbon group, etc. are mentioned, Especially, it is preferable that it is an aromatic hydrocarbon group.
The aliphatic hydrocarbon group may be linear, branched or cyclic. Specific examples of the aliphatic hydrocarbon group include a linear or branched alkyl group (particularly 1 to 20 carbon atoms), a linear or branched alkenyl group (particularly 2 to 20 carbon atoms), Examples thereof include a linear or branched alkynyl group (particularly, having 2 to 20 carbon atoms). The aliphatic hydrocarbon group is preferably a linear or branched alkyl group.
Examples of the aromatic hydrocarbon group include an aryl group and a naphthyl group. Examples of the aryl group include aryl groups having 6 to 18 carbon atoms such as a phenyl group, a tolyl group, and a xylyl group.
The substituent that the hydrocarbon group may have is not particularly limited, but specific examples include an aliphatic hydrocarbon group, an aromatic hydrocarbon group, a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, etc.) and the like. Can be mentioned. Specific examples and preferred embodiments of the aliphatic hydrocarbon group and the aromatic hydrocarbon group are as described above. The substituent is preferably an aliphatic hydrocarbon group.

In the formula (A1), R ^A12 and R ^A13 each independently represent a hydrocarbon group or a hydrocarbon oxy group (—OR: where R represents a hydrocarbon group) which may have a substituent. . Specific examples of the hydrocarbon group of the hydrocarbon group which may have a substituent and the hydrocarbon group (R) of the hydrocarbon oxy group are the same as the hydrocarbon group described above. Moreover, the specific example and suitable aspect of a substituent which a hydrocarbon group or a hydrocarbon oxy group may have are the same as the substituent mentioned above.
One of R ^A12 and R ^A13 is preferably an aromatic hydrocarbon group which may have a substituent. When one of R ^A12 and R ^{A13 is} an aromatic hydrocarbon group which may have a substituent, the other may have a phenyl group (especially having 6 to 18 carbon atoms) or an alkoxy group which may have a substituent ( Particularly preferred are those having 1 to 5 carbon atoms, and more preferred are phenyl groups (particularly 6 to 18 carbon atoms) which may have a substituent.

Specific examples of the monoacylphosphine oxide (A1) include benzoyl-diphenylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2,3,5,6-tetramethylbenzoyl-diphenylphosphine oxide, 3, Examples include 4-dimethylbenzoyl-diphenylphosphine oxide, 2,4,6-trimethylbenzoyl-phenylethoxyphosphine oxide, and the like.

The bisacylphosphine oxide (A2) is not particularly limited, and a known bisacylphosphine oxide can be used. As a suitable aspect of bisacylphosphine oxide (A2), the bisacylphosphine oxide represented by a following formula (A2) is mentioned, for example.

In the above formula (A2), R ^A21 to R ^A23 each independently represents a hydrocarbon group which may have a substituent. Specific examples and preferred embodiments of the hydrocarbon group and the substituent are the same as those of R ^A11 described above.

Specific examples of bisacylphosphine oxide (A2) include bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide and bis (2,6-dimethoxybenzoyl) -2,4,4-trimethyl-pentylphosphine oxide. And bis (2,6-dimethylbenzoyl) -ethylphosphine oxide.

The content of the initiator with respect to the total solid content in the curable composition is not particularly limited, but is preferably 0.01 to 2% by mass, and more preferably 0.02 to 1% by mass.

<Other ingredients>
The curable composition used by this invention may contain components other than the component mentioned above. Examples of such components include a solvent, an initiator, a chain transfer agent, a sensitizing dye, and a polymerization inhibition inhibitor.

[Gel fraction]
The gel fraction of the pressure-sensitive adhesive sheet of the present invention is 50% by mass or less. In particular, the content is preferably 10 to 40% by mass, and more preferably 20 to 30% by mass.
Here, a gel fraction represents the ratio of the gel component in an adhesive sheet, and specifically represents the value calculated by the following method.
That is, the pressure-sensitive adhesive sheet (0.3 g) is immersed in ethyl acetate (30 g) and allowed to stand at 40 ° C. for 16 hours. Thereby, components other than the gel component in an adhesive sheet melt | dissolve in a solvent. And the immersed adhesive sheet is taken out, dried, and its mass is measured. And the gel fraction of an adhesive sheet is computed from the following formula | equation.
“Gel fraction” = (mass of adhesive sheet after immersion) / (mass of adhesive sheet before immersion) × 100 (mass%)

[Crosslinking agent ratio]
The pressure-sensitive adhesive sheet of the present invention has a crosslinking agent amount ratio represented by the following formula (1) of 1.00 × 10 ⁻⁴ or less.
Crosslinking agent amount ratio = crosslinking agent content / crosslinking agent molecular weight × crosslinking agent crosslinkable group number / gel fraction (1)
Here, a crosslinking agent content rate represents content of the said crosslinking agent with respect to solid content whole quantity in the said curable composition, and a unit is the mass%. The molecular weight of the crosslinking agent represents the molecular weight of the crosslinking agent. The number of crosslinkable groups of the crosslinker represents the number of crosslinkable groups possessed by the crosslinker. Moreover, the said gel fraction represents the gel fraction of an adhesive sheet, and a unit is the mass%.
For example, curing containing 40 parts by mass (solid content) of an acrylic polymer solution, 60 parts by mass of a hydrogenated terpene resin, and 0.5 parts by mass (solid content) of a crosslinking agent (molecular weight: 801.02, crosslinkable group number: 3). When the adhesive composition is obtained by curing the adhesive composition and the gel fraction is 25% by mass, the crosslinking agent content is 0.5 ÷ (40 + 60 + 0.5) × 100 (% by mass), Since the crosslinking agent molecular weight is 716.86, the number of crosslinking agent crosslinking groups is 3, and the gel fraction is 25 (mass%), the crosslinking agent amount ratio is calculated to be 7.45 × 10 ⁻⁵ .
The amount ratio of the crosslinking agent is preferably 1.00 × 10 ⁻⁵ or more, and more preferably 6.00 × 10 ⁻⁵ or more.

[Method for producing adhesive sheet]
The pressure-sensitive adhesive sheet of the present invention can be obtained by curing the curable composition described above.
The method for curing the curable composition is not particularly limited. For example, the curable composition is applied onto a release sheet to form a curable layer, and this is heated or light (ultraviolet light, visible light, X-ray, etc.). ) A method of curing by irradiation is mentioned.

Examples of the release sheet include a film whose surface is treated with a silicone-based release agent and other release agents, and a film that itself has release properties.
Examples of the material constituting the release sheet include polyolefins such as polypropylene and polyethylene, polyester, nylon, and polyvinyl chloride.
The thickness of the release sheet is not particularly limited, but is preferably from 25 to 150 μm, more preferably from 25 to 75 μm, from the viewpoint that the handleability of the pressure-sensitive adhesive sheet is excellent.

Examples of the method for applying the curable composition include a method using a gravure coater, a comma coater, a bar coater, a knife coater, a die coater, a roll coater, and the like.

The heating method is not particularly limited, and for example, an air dryer, an oven, an infrared dryer, a heating drum, or the like can be used.
The heating temperature is not particularly limited, but is preferably 30 to 150 ° C, more preferably 40 to 120 ° C.
The heating time is not particularly limited, but drying in the coating apparatus is preferably 1 to 20 minutes, and heating after the coating apparatus, for example, in a winding form, is preferably from room temperature to 50 ° C.

Examples of the light irradiation method include a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, a metal halide lamp, a Deep-UV light, a xenon lamp, a chemical lamp, a carbon arc lamp, and the like. The energy of light irradiation is not particularly limited, but is preferably 0.1 to 10 J / cm ² .

The pressure-sensitive adhesive sheet of the present invention preferably does not contain a substrate from the viewpoint of elongation at break and suitability for bonding. The base material does not include the release sheet described above.

<Elongation at break>
The breaking elongation of the pressure-sensitive adhesive sheet of the present invention is preferably 700% or more.
Here, the elongation at break is determined by setting an adhesive sheet (2 cm × 5 cm) on a tensile tester (chucking at 1 cm at the end, freeing 3 cm), pulling until 300 mm / min until it breaks, and until breaking This is a value calculated by the following formula from the measured distance.
Elongation at break (%) = (distance pulled to break + 3 cm) / 3 cm × 100

<Relative permittivity (25 ° C)>
The relative dielectric constant at 25 ° C. of the pressure-sensitive adhesive sheet of the present invention is preferably 3.0 or less.
Here, the relative dielectric constant at 25 ° C. is evaluated as follows.
One surface of the pressure-sensitive adhesive sheet is bonded to an Al substrate having a length of 20 mm × width of 20 mm and a thickness of 0.5 mm, and then an Al substrate having the same size as the Al substrate is bonded to the other surface. Next, pressure defoaming treatment is performed at 40 ° C. and 5 atm for 60 minutes to prepare a sample for evaluating relative permittivity.
The thickness of the pressure-sensitive adhesive sheet is calculated by measuring the thickness of the sample at five locations with a micrometer and subtracting the thickness of two Al substrates from the average value.
Using the relative dielectric constant evaluation sample prepared above, impedance measurement at 100 kHz is performed with an impedance analyzer (Agilent 4294A), and the relative dielectric constant of the adhesive sheet is measured.
Specifically, the capacitance C is obtained by measuring the relative dielectric constant of the sample at 25 ° C. using an impedance analyzer (Agilent 4294A) at 100 kHz. Then, using the obtained capacitance C, the relative dielectric constant at 25 ° C. is calculated from the following formula (X).
Formula (X): relative dielectric constant = (capacitance C × thickness T) / (area S × vacuum dielectric constant ε ₀ )
The thickness T is the thickness of the pressure-sensitive adhesive sheet, the area S is the aluminum electrode area (vertical 20 mm × horizontal 20 mm), and the vacuum permittivity ε ₀ is a physical constant (8.854 × 10 ⁻¹² F / m). To do.

<Temperature change in relative permittivity>
It is preferable that the temperature change of the dielectric constant from 0 degreeC to 60 degreeC of the adhesive sheet of this invention is 15% or less. In particular, it is more preferable that the temperature change of the dielectric constant from −40 ° C. to 80 ° C. is 15% or less.
Here, the temperature change of the dielectric constant from −40 ° C. to 80 ° C. is evaluated as follows. 0 to 60 ° C. is measured in the same manner only by changing the temperature range.
As described above, a relative dielectric constant evaluation sample is prepared.
Then, the dielectric constant evaluation sample was heated stepwise from −40 ° C. to 80 ° C. in steps of 20 ° C., and the capacitance C was determined by impedance measurement at 100 kHz using an impedance analyzer (Agilent 4294A) at each temperature. Ask for. At each temperature, the sample is allowed to stand for 5 minutes until the temperature of the sample becomes constant.
Thereafter, using the obtained capacitance C, the relative dielectric constant at each temperature is calculated as described above.
The minimum value and the maximum value are selected from the calculated relative permittivity, and the temperature change (%) of the relative permittivity is obtained from the formula [(maximum value−minimum value) / minimum value × 100].

<Adhesion>
An adhesive sheet is a layer for ensuring the adhesiveness between members. In particular, the pressure-sensitive adhesive sheet of the present invention is suitably used for touch panel applications as described later.
Therefore, the 180-degree peel strength (adhesion strength) of the pressure-sensitive adhesive sheet obtained from the adhesive evaluation test described later is preferably 0.20 N / mm or more, more preferably 0.25 N / mm or more, and 0.3 N / mm or more. More preferably it is. The upper limit is not particularly limited, but is usually 2.0 N / mm or less in many cases. If the peel strength is within the above range, the pressure-sensitive adhesive sheet exhibits a predetermined elasticity, so that even when various members are deformed due to a temperature change, the deformation can be followed. As a result, it is arranged between the capacitive touch panel sensor and the protective substrate (cover member), between the capacitive touch panel sensor and the display device, or on the substrate and the substrate in the capacitive touch panel sensor. When an adhesive sheet is used between the conductive films provided with the detection electrodes, excellent adhesion retention force is maintained in a wide temperature range, and malfunction of the touch panel due to deterioration over time is less likely to occur.
As a measuring method of the adhesive evaluation test, the adhesive sheet is bonded to a glass substrate, and the 180 degree peel strength is obtained by a method in accordance with “10.4 Measurement of peeling adhesive strength” in JIS Z0237 of the adhesive sheet. Ask. More specifically, the adhesive sheet (width 25 mm × length 40 mm to 0 mm) is faced to the vicinity of the center of the glass plate (40 mm or more × 60 mm or more) so that the longitudinal direction of the adhesive sheet and the glass plate is aligned. And bonding at 10 to 40 kPa. Then, align the longitudinal direction of the Kapton film (width 25 mm x length 150 mm or more) on the exposed surface of the adhesive sheet so that one end of the Kapton film does not contact the adhesive sheet, and the entire area of the adhesive sheet is covered with the Kapton film. A kapton film and an adhesive sheet are bonded together to obtain a laminate. Next, one end of a Kapton film not in contact with the adhesive sheet is set in an autograph (manufactured by Shimadzu Corporation) in a shape that pulls (peels) in the direction of 180 degrees, and the peel strength is measured.

The thickness of the pressure-sensitive adhesive sheet of the present invention is not particularly limited, but is preferably 5 to 2500 μm, more preferably 10 to 500 μm, and further preferably 50 to 250 μm.

The use of the pressure-sensitive adhesive sheet of the present invention is not particularly limited, but is particularly useful as a pressure-sensitive adhesive sheet for touch panels.

[Laminate for touch panel, capacitive touch panel]
The laminated body for touchscreens of this invention is equipped with the adhesive sheet of this invention mentioned above, and a capacitive touch panel sensor.
One embodiment of the laminate for a touch panel of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view schematically showing one embodiment of the laminate for a touch panel of the present invention. In FIG. 1, the laminated body 100 for a touch panel includes an adhesive sheet 12 and a capacitive touch panel sensor 18.
Moreover, FIG. 2 is sectional drawing which represents typically another aspect of the laminated body for touchscreens of this invention. In FIG. 2, the laminate for touch panel 200 includes a protective substrate 20, an adhesive sheet 12, and a capacitive touch panel sensor 18.

Moreover, the capacitive touch panel of this invention is equipped with a capacitive touch panel sensor, the adhesive sheet of this invention mentioned above, and a display apparatus in this order.
One embodiment of the capacitive touch panel of the present invention will be described with reference to the drawings.
FIG. 3A is a cross-sectional view schematically illustrating one embodiment of the capacitive touch panel of the present invention. 3A, the capacitive touch panel 300 includes the capacitive touch panel sensor 18, the adhesive sheet 12, and the display device 40.
FIG. 3B is a cross-sectional view schematically showing another aspect of the capacitive touch panel of the present invention. In FIG. 3B, the capacitive touch panel 400 includes the protective substrate 20, the adhesive sheet 12, the capacitive touch panel sensor 18, the adhesive sheet 12, and the display device 40.

The capacitive touch panel sensor 18 is disposed on the display device (operator side), and uses a change in capacitance that occurs when an external conductor such as a human finger comes into contact (approaching). It is a sensor that detects the position of an external conductor such as a finger.
The configuration of the capacitive touch panel sensor 18 is not particularly limited, but usually has a detection electrode (especially, a detection electrode extending in the X direction and a detection electrode extending in the Y direction), and the static electricity of the detection electrode in contact with or close to the finger. The coordinates of the finger are specified by detecting the change in capacitance.
The protective substrate 20 is a substrate disposed on the adhesive sheet, and serves to protect a capacitive touch panel sensor 18 (to be described later) from the external environment, and its main surface constitutes a touch surface. The protective substrate 20 is preferably a transparent substrate, and a plastic film, a plastic plate, a glass plate, or the like is used. It is desirable that the thickness of the substrate is appropriately selected according to each application.
The display device 40 is a device having a display surface for displaying an image, and each member is arranged on the display screen side. The type of the display device 40 is not particularly limited, and a known display device can be used. For example, cathode ray tube (CRT) display, liquid crystal display (LCD), organic light emitting diode (OLED) display, vacuum fluorescent display (VFD), plasma display panel (PDP), surface field display (SED), field emission display (FED) or electronic paper (E-Paper).

Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these.

<Preparation of acrylic polymer (prepolymer) solution A>
30 parts by weight of 2-ethylhexyl acrylate (47 g), 60 parts by weight of isobornyl acrylate (93 g), 5 parts by weight of dodecyl acrylate (7.8 g), 5 parts by weight of hydroxyethyl acrylate (7.8 g), and Ethyl acetate (39 g) was mixed, and the system was stirred at 90 ° C. for 15 minutes under a nitrogen stream to remove oxygen in the system. Subsequently, azobisisobutyronitrile (0.04 g) was added and stirred at 90 ° C. for 3 hours. Thereafter, azobisisobutyronitrile (0.04 g) was added, the mixture was stirred at 90 ° C. for 2 hours, and toluene (65 g) was further added to obtain an acrylic polymer solution. The obtained acrylic polymer solution is referred to as “acrylic polymer solution A”.

<Preparation of acrylic polymer (prepolymer) solution B>
Instead of stirring at 90 ° C., an acrylic polymer solution was obtained by the same procedure as the preparation of the acrylic polymer solution A described above except that stirring was performed at 75 ° C. The obtained acrylic polymer solution is designated as acrylic polymer solution B.

<Preparation of acrylic polymer (prepolymer) solution C>
Instead of stirring at 90 ° C., an acrylic polymer solution was obtained by the same procedure as the preparation of the acrylic polymer solution A described above except that stirring was performed at 65 ° C. The obtained acrylic polymer solution is referred to as “acrylic polymer solution C”.

<Preparation of acrylic polymer (prepolymer) solution D>
95 parts by mass of butyl acrylate, 5 parts by mass of acrylic acid, 5 parts by mass of dodecyl acrylate, 0.1 part by mass of azobisisobutyronitrile, and 140 parts by mass of ethyl acetate were mixed, The mixture was reacted at 0 ° C. for 8 hours to obtain an acrylic polymer solution. The obtained acrylic polymer solution is designated as acrylic polymer solution D.

<Preparation of curable composition>
The components shown in Table 1 were mixed in the proportions (parts by mass) shown in the same table and stirred well to prepare curable compositions used in each Example and Comparative Example. In Table 1, parts by mass of the acrylic polymer solutions (A to D) and the crosslinking agent (1 to 3) represent parts by mass of the solid content.

<Manufacture of adhesive sheet>
Each curable composition mentioned above was apply | coated on peeling PET, the curable layer was formed, and heat processing (100 degreeC, 3 minutes) were performed using the clean oven (pre-curing). As a result, the curable layer was cured, and an adhesive sheet precursor was formed on the peeled PET. Another release PET was bonded onto the formed pressure-sensitive adhesive sheet precursor. Thus, the laminated body which has peeling PET, an adhesive sheet precursor, and peeling PET in this order was produced.
Furthermore, heat treatment (40 ° C., 72 hours) was performed on the obtained laminate using a clean oven. Thereby, the adhesive sheet (each adhesive sheet of an Example and a comparative example) was formed from the adhesive sheet precursor. The obtained adhesive sheet is sandwiched between two pieces of peeled PET.

<Gel fraction of adhesive sheet>
The release PET was peeled off from both surfaces of the obtained pressure-sensitive adhesive sheet (one sandwiched between two pieces of release PET). Next, the pressure-sensitive adhesive sheet (0.3 g) was immersed in ethyl acetate (30 g) and allowed to stand at 40 ° C. for 16 hours. Next, the immersed adhesive sheet was taken out, dried, and its mass was measured. And the gel fraction of the adhesive sheet was computed from the following formula | equation. The results are shown in Table 1.
“Gel fraction” = (mass of adhesive sheet after immersion) / (mass of adhesive sheet before immersion) × 100 (mass%)

<Elongation at break>
Cut the obtained pressure-sensitive adhesive sheet (between two pieces of peeled PET) to 2 cm x 5 cm, peel off the peeled PET from both sides, and set it on a tensile tester (chuck at the end 1 cm, 3 cm And then pulled until breaking at 300 mm / min, and the distance pulled until breaking was measured. The breaking elongation was calculated from the measured distance by the following formula. The results are shown in Table 1. Practically, the elongation at break is preferably 700% or more.
Elongation at break (%) = (distance pulled to break + 3 cm) / 3 cm × 100

<Processability>
The obtained pressure-sensitive adhesive sheet (sandwiched between two pieces of peeled PET) was punched into a 7 inch size with a punching machine (100 samples), and the protrusion of adhesive (adhesive sheet component) from the end was observed, and the following criteria From this, the workability was evaluated. The results are shown in Table 1. Practically, it is preferably 3 to 5, more preferably 4 to 5, and still more preferably 5.
-5: No sticking out of paste was observed in all samples after punching and after storage for 24 hours.
-4: No sticking out of the paste is seen in all samples, but sticking out is seen in some samples after 24 hours storage.
* 3: Paste of glue is seen in some samples when punched.
* 2: Paste of glue is seen in most samples when punched.
-1: Extrusion of glue is seen in all samples when punched.

<Adhesion suitability>
The peeled PET was peeled off from both sides of the obtained pressure-sensitive adhesive sheet (one sandwiched between two pieces of peeled PET), and a glass plate was bonded to one side (glass substrate / pressure-sensitive adhesive sheet). Next, the glass substrate / pressure-sensitive adhesive sheet surface was bonded to a 7-inch liquid crystal panel with a bonding machine (100 samples). One week after bonding, the distortion and bubbles of the liquid crystal panel were observed, and the bonding property was evaluated from the following criteria. The results are shown in Table 1. Practically, 4 to 5 is preferable, and 5 is more preferable.
5: No distortion or foam is seen in all samples.
4: Bubbles are not seen in all samples, but distortion is seen in some samples.
* 3: Distortion and foam are seen in some samples.
2: Strain or foam is observed in most samples.
-1: distortion or foam is seen in all samples.

<Adhesion>
The obtained pressure-sensitive adhesive sheet (between two pieces of peeled PET) was cut into 2.5 cm × 5 cm, and the peeled PET was peeled off from both sides. Next, one side of the pressure-sensitive adhesive sheet was attached to a glass substrate, and the other side was attached to a Kapton film. Subsequently, one end of the Kapton film was gripped using an autograph manufactured by Shimadzu Corporation, a 180 degree peel test (tensile speed of 300 cm / min) was performed, and an adhesion force (N / mm) was measured. The results are shown in Table 1. Practically, the adhesion is preferably 0.3 N / mm or more.

<Relative permittivity (25 ° C)>
The specific dielectric constant at 25 ° C. was evaluated for the obtained adhesive sheet. The evaluation method of the relative dielectric constant is as described above.
The results are shown in Table 1 (relative dielectric constant (25 ° C.)).

<Temperature change in relative permittivity>
The resulting adhesive sheet was evaluated for temperature change in relative dielectric constant from −40 ° C. to 80 ° C. The method for evaluating the temperature change of the dielectric constant is as described above.
The results are shown in Table 1 (Temperature change in relative permittivity (%)). From the viewpoint of suppressing the occurrence of malfunction when used for a touch panel, it is preferable that the temperature change of the dielectric constant is small.

The crosslinker content, crosslinker molecular weight, crosslinker crosslinkable group number, gel fraction, and crosslinker amount ratio in Table 1 are the above-mentioned crosslinker content, crosslinker molecular weight, and crosslinker crosslinkable group number, respectively. , Gel fraction, and crosslinker amount ratio. Moreover, the polymer molecular weight in Table 1 represents the weight average molecular weight of the acrylic polymer (prepolymer) in the acrylic polymer solution used to prepare the curable composition.

The details of each component described in Table 1 are as follows.
Acrylic polymer solution A: Acrylic polymer solution A prepared as described above
Acrylic polymer solution B: Acrylic polymer solution B prepared as described above
Acrylic polymer solution C: Acrylic polymer solution C prepared as described above
Acrylic polymer solution D: Acrylic polymer solution D prepared as described above
-Modified terpene resin: YS resin TO85 (aromatic modified terpene resin, manufactured by Yasuhara Chemical Co., Ltd.)
-Hydrogenated terpene resin: Clearon P85 (hydrogenated terpene resin, manufactured by Yasuhara Chemical Co., Ltd.)
-Rubber: Polybest 110 (liquid polybutadiene, manufactured by evonik)
・ Hydrogenated rosin resin: Pine Crystal KE359 (hydrogenated rosin ester resin, manufactured by Arakawa Chemical Industries)
-Polycarbonate: Polycarbonate-Ethylene glycol: Ethylene glycol-Terpene resin: YS Polystar T130 (terpene phenol resin, manufactured by Yasuhara Chemical Co., Ltd.)
Crosslinking agent 1: Takenate D-140N (isocyanate-based crosslinking agent, trimethylolpropane adduct of diisocyanate isophorone (trimer), molecular weight: 801.02, number of crosslinkable groups (isocyanate groups): 3, Mitsui Chemicals, Inc. Made)
Crosslinking agent 2: Coronate L (isocyanate crosslinking agent, trimethylolpropane adduct of trimylene diisocyanate (trimer), molecular weight: 656.64, number of crosslinkable groups (isocyanate groups): 3, manufactured by Nippon Polyurethane Industry Co., Ltd. )
Crosslinking agent 3: Isocyanate-based crosslinking agent (trimethylolpropane adduct of hexamethylene diisocyanate (trimer), molecular weight: 638.75, number of crosslinkable groups (isocyanate groups): 3)

As can be seen from Table 1, the pressure-sensitive adhesive sheet is obtained by curing a curable composition containing a specific plasticizer and a crosslinking agent, and has a gel fraction of 50% by mass or less and a crosslinking agent amount ratio. In each of Examples 1 to 12, which were 1.00 × 10 ⁻⁴ or less, the elongation at break was large, the temperature change of the relative dielectric constant was small, and the workability, bonding suitability and adhesion were excellent.
Among them, Examples 1 to 10 and 12 to 14 in which the specific plasticizer is at least one plasticizer selected from the group consisting of rubber, hydrogenated terpene resin and modified terpene resin have a change in temperature of relative permittivity. It was small.
Among them, Examples 1-2, 4-6, 9-10, and 12-14 having a gel fraction of 20-30% by mass were more excellent in workability and adhesion.
Moreover, from the comparison with Example 1 and 14, Example 14 whose specific plasticizer is a hydrogenated terpene resin was more excellent in adhesiveness.

On the other hand, Comparative Examples 1-2 and 8 having a cross-linking agent amount ratio exceeding 1.00 × 10 ⁻⁴ had a low elongation at break and insufficient bonding suitability.
Further, Comparative Example 3 having a gel fraction exceeding 50% by mass had a low elongation at break, insufficient bonding suitability, and insufficient adhesion.
Further, Comparative Examples 4 to 7 and 9 using a curable composition not containing a specific plasticizer had insufficient adhesion or had a large temperature change in relative permittivity.

12 Adhesive Sheet 18 Capacitive Touch Panel Sensor 20 Protective Substrate 40

Display Device

100, 200

Laminate

300, 400 for Touch Panel Capacitive Touch Panel

Claims

A pressure-sensitive adhesive sheet obtained by curing a curable composition,
The curable composition contains at least one plasticizer selected from the group consisting of rubber, hydrogenated terpene resin, modified terpene resin and hydrogenated rosin resin, and a crosslinking agent,
The gel fraction is 50% by mass or less,
The adhesive sheet whose cross-linking agent amount ratio represented by the following formula (1) is 1.00 × 10 −4 or less.
Crosslinking agent amount ratio = crosslinking agent content / crosslinking agent molecular weight × crosslinking agent crosslinkable group number / gel fraction (1)
Here, a crosslinking agent content rate represents content of the said crosslinking agent with respect to solid content whole quantity in the said curable composition, and a unit is the mass%. The crosslinking agent molecular weight represents the molecular weight of the crosslinking agent. The number of crosslinkable crosslinkable groups represents the number of crosslinkable groups possessed by the crosslinker. A gel fraction represents the gel fraction of the said adhesive sheet, and a unit is the mass%.
The pressure-sensitive adhesive sheet according to claim 1, wherein the gel fraction is 10 to 30% by mass.
The pressure-sensitive adhesive sheet according to claim 1 or 2, wherein the curable composition contains a prepolymer.
The pressure-sensitive adhesive sheet according to claim 3, wherein the prepolymer has a weight average molecular weight of 200,000 or more.
The pressure-sensitive adhesive sheet according to claim 3 or 4, wherein the method for forming the prepolymer is thermal polymerization.
The pressure-sensitive adhesive sheet according to any one of claims 1 to 5, wherein the adhesive strength to glass is 0.2 N / mm or more.
The pressure-sensitive adhesive sheet according to any one of claims 1 to 6, wherein the elongation at break is 700% or more.
The pressure-sensitive adhesive sheet according to any one of claims 1 to 7, wherein the crosslinking agent has a molecular weight of 10,000 or less.
The pressure-sensitive adhesive sheet according to any one of claims 1 to 8, wherein a relative dielectric constant at 25 ° C is 3.0 or less.
The pressure-sensitive adhesive sheet according to any one of claims 1 to 9, wherein a change in temperature of a relative dielectric constant from 0 ° C to 60 ° C is 15% or less.
The pressure-sensitive adhesive sheet according to claim 10, wherein the temperature change of the relative dielectric constant from -40 ° C to 80 ° C is 15% or less.
The pressure-sensitive adhesive sheet according to any one of claims 1 to 11, wherein the crosslinking agent amount ratio is 6.00 × 10 -5 or more.
The pressure-sensitive adhesive sheet according to any one of claims 1 to 12, which does not contain a substrate.
The pressure-sensitive adhesive sheet according to any one of claims 1 to 13, wherein the crosslinking agent is an isocyanate-based crosslinking agent.
The pressure-sensitive adhesive sheet according to any one of claims 1 to 14, wherein the plasticizer is at least one plasticizer selected from the group consisting of rubber, hydrogenated terpene resin and modified terpene resin.
The pressure-sensitive adhesive sheet according to any one of claims 1 to 15, which is a pressure-sensitive adhesive sheet for a touch panel.
A laminate for a touch panel comprising the pressure-sensitive adhesive sheet according to claim 16 and a capacitive touch panel sensor.
In addition, with a protective substrate,
The laminated body for touchscreens of Claim 17 provided with the said protective substrate, the said adhesive sheet, and the said electrostatic capacitance type touch panel sensor in this order.
A capacitive touch panel comprising a capacitive touch panel sensor, the adhesive sheet according to claim 16, and a display device in this order.