WO2016047361A1 - Active energy ray-curable adhesive composition, adhesive sheet, laminate for touch panels, and capacitive touch panel - Google Patents

Abstract

The present invention relates to: an active energy ray-curable adhesive composition which contains a compound having a hydrophilic group and an ethylenically unsaturated group and a compound represented by general formula (I); an adhesive sheet; a laminate for touch panels; and a capacitive touch panel. In general formula (I), each of V¹, V², V³ and V⁴ independently represents a hydrogen atom or a substituent. In general formula (I), n represents an integer of from 1 to 5 (inclusive).

Description

Active energy ray-curable pressure-sensitive adhesive composition, pressure-sensitive adhesive sheet, laminate for touch panel, and capacitive touch panel

The present invention relates to an active energy ray-curable pressure-sensitive adhesive composition, a pressure-sensitive 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 photocurable composition or the like is used in order to bring each member such as a display device or a touch panel sensor into close contact. In general, the photocurable composition is formed into a sheet and used as an adhesive sheet.

For example, in claim 1 of Patent Document 1, “(A) a polymer having vinylpyrrolidone as an essential constituent monomer unit and a K value of 20 or more,
(B) a compound having a (meth) acryloyl group and a hydrophilic group, and
(C) containing a photo radical polymerization initiator,
The weight ratio of the component (A) and the component (B) ((A) / (B)) is 90/10 to 25/75,
(1) (B) component contains (B-1) diglycidyl ether (meth) acrylic acid 2-mol adduct, and (B-1) component content is the total of (A) component and (B) component 1 part by weight or more and 50 parts by weight or less with respect to 100 parts by weight, or
(2) Component (B) is selected from the group consisting of (B-2) (meth) acrylic acid multimer, caprolactone ring-opened product of (meth) acrylic acid, and acid anhydride adduct of hydroxyalkyl (meth) acrylate A photocurable composition for adhesives characterized by comprising at least one is disclosed. In Examples of Patent Document 1, Irgacure 2959 (1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one) is used as a radical photopolymerization initiator. Including aspects are disclosed.

Japanese Patent No. 5136058

An adhesive sheet used for a capacitive touch panel is required to have excellent adhesiveness, optical characteristics, and the like.
When the present inventor examined a composition containing Irgacure 2959 as disclosed in Examples of Patent Document 1, the photocurable composition contains a polymerization initiator as described above (Comparative Example of the present specification). 2) It became clear that the adhesive sheet obtained from this composition may have low adhesiveness.

For this reason, when the amount of the polymerization initiator is increased for the purpose of reducing the amount of residual monomer in the pressure-sensitive adhesive sheet (Comparative Example 1 in this specification), the pressure-sensitive adhesive property of the pressure-sensitive adhesive sheet after the high-temperature test is deteriorated. Became clear.
Moreover, when the quantity of the said polymerization initiator was increased, it became clear that the undissolved residue of the said polymerization initiator arises by lack of solubility, and a haze arises in an adhesive sheet. When haze is generated in this way, the visibility decreases when used for a touch panel or the like. Moreover, it became clear that the haze of the pressure sensitive adhesive sheet after the high humidity test is further deteriorated than that of the pressure sensitive adhesive sheet before the high humidity test.

Furthermore, the composition may be used after being refrigerated for a long period. When this inventor evaluated the characteristic of the said composition refrigerated over the predetermined period, it became clear that a deposit generate | occur | produces.

Therefore, in view of the above circumstances, the present invention exhibits excellent adhesiveness and optical characteristics, is suppressed from deterioration of adhesiveness even after standing in a high temperature environment, and after standing in a high humidity environment. However, an object of the present invention is to provide an active energy ray-curable pressure-sensitive adhesive composition that can form a pressure-sensitive adhesive sheet in which deterioration of optical properties is suppressed and that suppresses generation of precipitates even during storage in a low-temperature environment. And
Moreover, an object of this invention is to provide the adhesive sheet formed from the said active energy ray hardening-type adhesive composition, the laminated body for touchscreens provided with the said adhesive sheet, and a capacitive touch panel.

As a result of earnestly examining the above problems, the present inventors have found that the predetermined compound has higher hydrophilicity, excellent compatibility in the composition, precipitation of the polymerization initiator is suppressed, and the above problems can be solved, The present invention has been reached.
The present invention is based on the above knowledge and the like, and specifically, solves the above problems by the following configuration.

[1] An active energy ray-curable pressure-sensitive adhesive composition comprising a compound having a hydrophilic group and an ethylenically unsaturated group and a compound represented by the following general formula (I).

In general formula (I), V ¹ , V ² , V ³ , and V ⁴ each independently represent a hydrogen atom or a substituent. In general formula (I), n represents an integer of 1 or more and 5 or less.
[2] The active energy ray-curable pressure-sensitive adhesive composition according to [1], wherein n is 1 in the general formula (I).
[3] The active energy ray-curable pressure-sensitive adhesive composition according to [1] or [2], wherein the compound having a hydrophilic group and an ethylenically unsaturated group is a (meth) acrylic compound.
[4] The active energy ray-curable pressure-sensitive adhesive composition according to any one of [1] to [3], wherein the hydrophilic group is a hydroxyl group or a carboxyl group.
[5] The activity according to any one of [1] to [4], wherein the content of the compound represented by the general formula (I) is 1 to 10% by mass relative to the total mass of the composition Energy ray-curable pressure-sensitive adhesive composition.
[6] The activity according to any one of [1] to [5], wherein the content of the compound represented by the general formula (I) is 2 to 7% by mass relative to the total mass of the composition Energy ray-curable pressure-sensitive adhesive composition.
[7] Further, a (meth) acrylic compound having a hydrophobic group is included,
The active energy ray according to any one of [1] to [6], wherein the content of the (meth) acrylic compound having a hydrophobic group is 10 to 30% by mass relative to the total mass of the composition A curable adhesive composition.
[8] The active energy ray-curable pressure-sensitive adhesive composition according to [7], wherein the homopolymer of the (meth) acrylic compound having a hydrophobic group has a glass transition temperature of −80 ° C. to + 20 ° C.
[9] The active energy ray-curable pressure-sensitive adhesive composition according to any one of [1] to [8], further including a cross-linking agent, wherein the cross-linking agent includes at least a polyfunctional acrylamide.
[10] The active energy ray-curable pressure-sensitive adhesive composition according to [9], wherein the polyfunctional acrylamide is at least one selected from the group consisting of the following compounds 3 to 6.

[11] The active energy ray-curable pressure-sensitive adhesive composition according to [9] or [10], wherein the content of the crosslinking agent is 0.1 to 10% by mass relative to the total mass of the composition.
[12] The active energy ray-curable pressure-sensitive adhesive composition according to any one of [1] to [11], which is substantially free of water.
[13] A pressure-sensitive adhesive sheet obtained by irradiating the active energy ray-curable pressure-sensitive adhesive composition according to any one of [1] to [12] with active energy rays.
[14] A laminate for a touch panel, comprising the adhesive sheet according to [13] and a capacitive touch panel sensor.
[15] Furthermore, a protective substrate is provided,
The laminate for a touch panel according to [14], comprising a capacitive touch panel sensor, an adhesive sheet, and a protective substrate in this order.
[16] A capacitive touch panel comprising a display device, the adhesive sheet according to [13], and a capacitive touch panel sensor in this order.

As shown below, according to the present invention, after exhibiting excellent adhesiveness and optical properties, the deterioration of adhesiveness is suppressed even after standing in a high temperature environment, and after standing in a high humidity environment However, it is possible to provide an active energy ray-curable pressure-sensitive adhesive composition that can form a pressure-sensitive adhesive sheet in which deterioration of optical properties is suppressed and that suppresses generation of precipitates even during storage in a low-temperature environment. .
Moreover, according to this invention, the laminated body for touchscreens provided with the said adhesive sheet formed from the said active energy ray hardening-type adhesive composition, the said adhesive sheet, and a capacitive touch panel can be provided.

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.

Hereinafter, the active energy ray-curable pressure-sensitive adhesive composition of the present invention, the pressure-sensitive adhesive sheet formed from the above-mentioned active energy ray-curable pressure-sensitive adhesive composition, the laminate for a touch panel including the pressure-sensitive adhesive sheet, and the capacitive touch panel will be described. To do.
In this specification, (meth) acrylate represents acrylate or methacrylate, (meth) acryloyl represents acryloyl or methacryloyl, 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.

[Active energy ray-curable pressure-sensitive adhesive composition]
The active energy ray-curable pressure-sensitive adhesive composition of the present invention (hereinafter also referred to as the composition of the present invention)
The compound which has a hydrophilic group and an ethylenically unsaturated group, and the compound represented by the following general formula (I) are included.

In general formula (I), V ¹ , V ² , V ³ , and V ⁴ each independently represent a hydrogen atom or a substituent. In general formula (I), n represents an integer of 1 to 5.

Since the composition of this invention takes such a structure, it is thought that a desired effect is acquired. The reason is not clear, but it is presumed that it is as follows.
As described above, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one, which is a polymerization initiator used in Patent Document 1, has hydrophilicity. Low. When this is used for a composition, the said polymerization initiator may precipitate from a composition. It is thought that haze deteriorates due to the presence of such precipitates. In addition, since the polymerization initiator has low hydrophilicity and low compatibility with the compound having a hydrophilic group and an ethylenically unsaturated group, the residual monomer in the pressure-sensitive adhesive sheet increases, and high adhesiveness is obtained. There may not be.
Moreover, in this case, the adhesiveness of the adhesive sheet after the high temperature test may be lower than the adhesiveness before the high temperature test.

On the other hand, in the present invention, the compound represented by the general formula (I) has a higher hydrophilicity than the polymerization initiator, and is compatible with a compound having a hydrophilic group and an ethylenically unsaturated group in the composition. Excellent. By this, it is thought that many compounds represented by general formula (I) can be mix | blended in a composition, and precipitation is suppressed. The reason why the compatibility of the above compound is good is not clear, but because the above compound has an ethyleneoxy group, it is considered that the above compound and a compound having a hydrophilic group and an ethylenically unsaturated group have an affinity. It is done.

Thus, by having good compatibility of the compound represented by the general formula (I), the compound represented by the general formula (I) is prevented from precipitating from the composition or bleeding out from the adhesive sheet, It is presumed that haze can be lowered. Moreover, it is estimated that the quantity of the residual monomer in an adhesive sheet can be reduced and the outstanding adhesiveness can be expressed.
Moreover, since the compound represented by general formula (I) has an ethyleneoxy group, it is thought that it can suppress that an optical characteristic falls before and after a high-humidity test. This is presumed to be because the above compound has a high affinity with water and hardly condenses water under high humidity conditions.
Furthermore, as described above, the compound represented by the general formula (I) has a high compatibility with the compound having a hydrophilic group and an ethylenically unsaturated group, so that the so-called residual monomer amount can be reduced. As a result, during the high temperature test, there is little bleeding out of the residual monomer to the pressure-sensitive adhesive sheet surface, and a decrease in pressure-sensitive adhesiveness is suppressed.

Hereinafter, each component will be described in detail.
<Compound having hydrophilic group and ethylenically unsaturated group>
The composition of the present invention contains a compound having a hydrophilic group and an ethylenically unsaturated group.
The compound has a hydrophilic group and an ethylenically unsaturated group.

The hydrophilic group is not particularly limited. Examples thereof include a hydroxyl group, a carboxyl group, an amine group, a sulfo group, an inorganic salt thereof, a betaine structure, and an amide bond. Of these, a hydroxyl group or a carboxyl group is preferred. The number of hydrophilic groups in the molecule of the above compound is preferably 1 to 3.
The hydrophilic group can be bonded to the ethylenically unsaturated group directly or through an organic group. The organic group can be divalent or higher. Examples of the organic group include a hydrocarbon group that may have a hetero atom, an ester bond, an ether bond, and a combination thereof.
The hydrocarbon group is not particularly limited. Specific examples of the hydrocarbon group preferably include an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or a group obtained by combining these. The aliphatic hydrocarbon group may be linear, branched, or cyclic, and more specifically, a linear aliphatic hydrocarbon group, a branched aliphatic hydrocarbon group, a cyclic aliphatic. Examples include hydrocarbon groups (alicyclic hydrocarbon groups).
Examples of the aliphatic hydrocarbon group include divalent aliphatic hydrocarbon groups such as an alkylene group, a cycloalkylene group, and an alkenylene group. Examples of the aromatic hydrocarbon group include divalent aromatic hydrocarbon groups such as a phenylene group and a naphthylene group.
The hydrocarbon group preferably has 1 to 5 carbon atoms.
The hetero atom is not particularly limited. For example, an oxygen atom, a nitrogen atom, a sulfur atom, and a halogen are mentioned. Heteroatoms may be used alone or in combination of two or more. The heteroatom may be a combination with a carbon atom and / or a hydrogen atom.
Specific examples of the organic group include a methylene group, an ethylene group, and a propylene group; residues of methyl ester, ethyl ester, and propyl ester.

The ethylenically unsaturated group is not particularly limited as long as it is a group having an ethylenically unsaturated bond (C = C). The number of ethylenically unsaturated groups in the molecule of the above compound is preferably 1 to 4. Examples of the ethylenically unsaturated group include a vinyl group, vinylene group, (meth) acryloyl group, (meth) acryloyloxy group, and (meth) acrylamide group.

Examples of the compound having a hydrophilic group and an ethylenically unsaturated group include (meth) acrylic compounds; amide compounds such as N-vinylpyrrolidone.
A compound having a hydrophilic group and an ethylenically unsaturated group has an amide bond as the hydrophilic group, and the amide bond and the ethylenically unsaturated group are (meth) acrylamide bonds (CH ₂ ═CR—CO—NH—. When R is a hydrogen atom or a methyl group, the number of (meth) acrylamide bonds in one molecule of the compound having a hydrophilic group and an ethylenically unsaturated group is preferably one. One of them.
The compound having a hydrophilic group and an ethylenically unsaturated group is preferably a (meth) acrylic compound, more preferably a (meth) acrylic acid alkyl ester, and a monofunctional compound represented by formula A ( More preferred are meth) acrylate monomers.
Formula A CH ₂ ═CR ₁ —COO—R ₂ —X _n
In Formula A, R ₁ represents a hydrogen atom or an alkyl group. The alkyl group preferably has 1 to 3 carbon atoms, and more preferably 1 carbon atom.
R ₂ represents a hydrocarbon group. Among these, the number of carbon atoms (carbon number) in the hydrocarbon group represented by R ₂ is preferably 1 to 5.
X represents a hydrophilic group. n is preferably 1 to 3.

Examples of the compound having a hydrophilic group and an ethylenically unsaturated group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl ( (Meth) acrylate, hydroxy group-containing (meth) acrylate such as glycerin mono (meth) acrylate;
(Meth) acrylic acid and their carboxylates; nitrogen atom-containing (meth) acrylates such as dimethylaminoethyl (meth) acrylate, 2-morpholinoethyl (meth) acrylate; methoxyethyl (meth) acrylate, 3-methoxy (Meth) acrylate having an ether bond such as butyl (meth) acrylate, methoxydipropylene glycol (meth) acrylate, methoxytripropylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, phenoxyethyl (meth) acrylate; (Meth) acrylamide, 2-hydroxyethyl (meth) acrylamide, 2-acrylamido-2-methylpropanesulfonic acid and its sulfonate, etc. Mono (meth) acrylamide compound having one linkage thereof;
N-methacryloyloxyethyl-N, N-dimethylammonium-N-methylcarboxybetaine, 2- (methacryloyloxy) ethyl 2-trimethylammonio) ethyl phosphate, N- (3-sulfopropyl) -N- (methacryloxyethyl) Examples thereof include betaine compounds such as —N, N-dimethylammonium betaine and N- (4-sulfobutyl) -N- (methacryloylaminopropyl) -N, N-diammonium betaine.

Of these, hydroxy group-containing (meth) acrylate and (meth) acrylic acid are preferable, and 2-hydroxyethyl (meth) acrylate and (meth) acrylic acid are more preferable.

The glass transition temperature of a homopolymer of a compound having a hydrophilic group and an ethylenically unsaturated group is
It is preferably −90 to + 250 ° C., more preferably −50 to + 110 ° C.
Examples of the compound having a hydrophilic group and an ethylenically unsaturated group that can form a homopolymer having a glass transition temperature in such a range include:
2-hydroxyethyl (meth) acrylate (glass transition temperature of homopolymer of acrylate: 7 ° C., homopolymer glass transition temperature of methacrylate: 55 ° C.),
2-hydroxypropyl (meth) acrylate (glass transition temperature of homopolymer of acrylate: −7 ° C., homopolymer glass transition temperature of methacrylate: 26 ° C.),
2-hydroxybutyl (meth) acrylate (glass transition temperature of homopolymer of acrylate: -38 ° C.),
Acrylic acid (homopolymer glass transition temperature: 106 ° C.),
And methacrylic acid (homopolymer glass transition temperature: 227 ° C.).

The glass transition temperature of the (meth) acrylate homopolymer is described in J. Org. Brandup,
E. H. Immergut, Polymer Handbook, 2nd Ed. , J. et al. Wiley, New York 1975, photocuring technology data book (Technonet Books, Inc.), POLYMER HANDBOOK (Polymer Handbook) 3rd edition, Chapter 6, page 209, and the like.

The compounds having a hydrophilic group and an ethylenically unsaturated group can be used alone or in combination of two or more.
Examples of the combination of the compound having a hydrophilic group and an ethylenically unsaturated group include a combination of a hydroxy group-containing (meth) acrylate and (meth) acrylic acid and / or an amide-based compound. A combination of (meth) acrylate and (meth) acrylic acid is preferred.

Ratio (mass) of (meth) acrylic acid and / or amide compound to hydroxy group-containing (meth) acrylate ([(meth) acrylic acid and / or amide compound] / hydroxy group-containing (meth) acrylate) Is preferably 1 to 90, more preferably 1 to 30.

<Compound represented by formula (I)>
The composition of the present invention contains a compound represented by the general formula (I) as a polymerization initiator. The compound represented by the general formula (I) is a so-called “photopolymerization initiator” having a function of initiating a polymerization reaction of a compound having an ethylenically unsaturated group by irradiation with active energy rays.

In general formula (I), V ¹ , V ² , V ³ , and V ⁴ each independently represent a hydrogen atom or a substituent.
Examples of the substituent include aliphatic hydrocarbon groups (for example, alkyl groups), aromatic hydrocarbon groups, halogen atoms (fluorine atoms, chlorine atoms, bromine atoms, etc.), alkoxy groups, hydroxy groups, alkylthio groups, mercapto groups. , Acyl group, amino group and the like.

In V ¹ to V ⁴ , the number of carbon atoms of the alkyl group is preferably 1 to 6 carbon atoms, and more preferably 1 to 3 carbon atoms.
In V ¹ to V ⁴ , the alkyl group may be a linear alkyl group or a branched alkyl group. Moreover, the alkyl group may have an alicyclic structure.
Examples of the alkyl group in V ¹ to V ⁴ include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, n-hexyl group, Examples thereof include a cyclohexyl group, and a methyl group, an ethyl group, an n-propyl group, and an isopropyl group are preferable.

In V ¹ to V ⁴ , the number of carbon atoms of the alkoxy group is preferably 1 to 6 carbon atoms, and more preferably 1 to 3 carbon atoms.
In V ¹ to V ⁴ , the alkoxy group may be a linear alkoxy group or a branched alkoxy group. Moreover, the alkoxy group may have an alicyclic structure.
Examples of the alkoxy group for V ¹ to V ⁴ include methoxy group, ethoxy group, n-propyloxy group, isopropyloxy group, n-butoxy group, sec-butoxy group, tert-butoxy group, n-pentyloxy group, n- Examples thereof include a hexyloxy group and a cyclohexyloxy group, and a methoxy group, an ethoxy group, an n-propyloxy group, and an isopropyloxy group are preferable.

In V ¹ to V ⁴ , the alkylthio group preferably has 1 to 6 carbon atoms, more preferably 1 to 4 carbon atoms.
In V ¹ to V ⁴ , the alkylthio group may be a linear alkylthio group or a branched alkylthio group. Moreover, the alkylthio group may have an alicyclic structure.
Examples of the alkylthio group in V ¹ to V ⁴ include a methylthio group, an ethylthio group, an n-propylthio group, an isopropylthio group, an n-butylthio group, a sec-butylthio group, a tert-butylthio group, an n-pentylthio group, and an n-hexylthio group. And a cyclohexylthio group, and a methylthio group, an ethylthio group, an n-propylthio group, and an isopropylthio group are preferable.

In V ¹ to V ⁴ , the number of carbon atoms of the acyl group is preferably 1 to 6 carbon atoms, and more preferably 1 to 3 carbon atoms.
In V ¹ to V ⁴ , the acyl group may be a straight chain acyl group or a branched chain acyl group.
Examples of the acyl group in V ¹ to V ⁴ include a formyl group, an acetyl group, an ethyl acyl group, an n-propyl acyl group, and an isopropyl acyl group, and a formyl group, an acetyl group, and an ethyl acyl group are preferable.

V ¹ to V ⁴ are preferably a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group or an alkylthio group, more preferably a hydrogen atom, an alkoxy group or an alkylthio group, and most preferably a hydrogen atom.

Further, as a more preferable form of the compound represented by the general formula (I), a form in which 2 or more (preferably 3 or more, most preferably 4) of V ¹ to V ⁴ is a hydrogen atom is exemplified. It is done.

In general formula (I), n is an integer of 1 or more and 5 or less.
Generation | occurrence | production of a precipitate can be suppressed because n is 1 or more in general formula (I). Further, when n is 5 or less, the sensitivity to light is kept high, and the adhesive strength to various substrates (that is, the adhesive strength before irradiation with active energy rays) is improved.
N is preferably 1 or more and 3 or less, more preferably 1 or more and 2 or less, and particularly preferably 1.
On the other hand, when n is 0, the hydrophilicity is low, the compatibility with the compound having a hydrophilic group and an ethylenically unsaturated group in the composition is poor, and precipitates and residual monomers are present. Tends to occur. On the other hand, when n exceeds 5, the molecular weight of the polymerization initiator increases too much, causing a decrease in the dispersibility of the polymerizable compound in the composition, and the sensitivity of the composition tends to decrease.

Hereinafter, although the specific example (exemplary compound) of the compound represented by general formula (I) is shown, the compound represented by general formula (I) is not limited to these.

One of the preferred embodiments is that the compound represented by the general formula (I) is liquid at 23 ° C.

The compound represented by the general formula (I) is not particularly limited for its production. For example, it can be synthesized according to the method described in paragraphs 0067 to 0071 and 0112 to 0115 of JP 2000-186242 A. Each of the above compounds can be used alone or in combination of two or more.

The content of the compound represented by the general formula (I) is preferably 1 to 10% by mass, more preferably 2 to 10% by mass with respect to the total mass of the composition, and 2 to 7% by mass. % Is more preferable.

<Other ingredients>
((Meth) acrylic compound having hydrophobic group)
The composition of the present invention preferably further contains a (meth) acrylic compound having a hydrophobic group. When the composition of the present invention further contains a (meth) acrylic compound having a hydrophobic group, the glass transition temperature of the polymer forming the pressure-sensitive adhesive sheet can be easily adjusted, and the pressure-sensitive adhesive property is excellent.
In addition, it is mentioned as one of the aspects with preferable that the (meth) acrylic-type compound which has a hydrophobic group does not have a hydrophilic group (for example, a hydroxyl group, a carboxy group, an amine, an amide bond).

As a hydrophobic group which the said (meth) acrylic-type compound has, a hydrocarbon group is mentioned, for example. One preferred embodiment is that the hydrocarbon group does not have a functional group.
Specific examples of the hydrocarbon group preferably include an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or a group obtained by combining these. The aliphatic hydrocarbon group may be linear, branched, or cyclic, and more specifically, a linear aliphatic hydrocarbon group, a branched aliphatic hydrocarbon group, a cyclic aliphatic. Examples include hydrocarbon groups (alicyclic hydrocarbon groups).
Examples of the aliphatic hydrocarbon group include an alkyl group, a cycloalkyl group, and an alkenyl group. Examples of the aromatic hydrocarbon group include a phenyl group and a naphthyl group.
The hydrocarbon group preferably has 1 to 18 carbon atoms.

The (meth) acrylic compound having a hydrophobic group is preferably (meth) acrylate, more preferably (meth) acrylate having a hydrocarbon group in the ester moiety.
One of the preferred embodiments of the hydrocarbon group is that it is formed of only a carbon atom and a hydrogen atom.
Further, the (meth) acrylic compound having a hydrophobic group is preferably a mono (meth) acrylate having one (meth) acryloyloxy group.

Specific examples of the (meth) acrylic compound having a hydrophobic group include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, cyclohexyl Linear aliphatic hydrocarbon groups such as (meth) acrylate, 2-ethylhexyl (meth) acrylate, dodecyl (meth) acrylate, isononyl (meth) acrylate, isodecynyl (meth) acrylate, stearyl (meth) acrylate, branched chain (Meth) acrylate having an aliphatic hydrocarbon group;
(Meth) acrylate having a cyclic aliphatic hydrocarbon group (alicyclic hydrocarbon group) such as isobornyl (meth) acrylate, dicyclohexyl (meth) acrylate, 2-dicyclohexyloxyethyl (meth) acrylate; phenyl (meth) acrylate (Meth) acrylate groups having an aromatic hydrocarbon group such as

The glass transition temperature of the homopolymer of a (meth) acrylic compound having a hydrophobic group is preferably −80 ° C. to + 100 ° C., more preferably −80 to + 20 ° C. That is, when a (meth) acrylic compound having a hydrophobic group is used to form a homopolymer having a molecular weight of 5,000 to 200,000, the hydrophobic group having a glass transition temperature of −80 ° C. to + 100 ° C. It is preferable that it is a (meth) acrylic compound.
As a (meth) acrylic compound having a hydrophobic group capable of forming a homopolymer having a glass transition temperature in such a range, for example,
Isostearyl acrylate (glass transition temperature of homopolymer of acrylate: −58 ° C.),
Lauryl (meth) acrylate (glass transition temperature of homopolymer of acrylate: −30 ° C., homopolymer glass transition temperature of methacrylate: −65 ° C.),
2-ethylhexyl methacrylate (glass transition temperature of homopolymer of methacrylate: −10 ° C.),
Butyl methacrylate (methacrylate homopolymer glass transition temperature: 20 ° C.),
And isobornyl acrylate (glass transition temperature of homopolymer of isobornyl acrylate: 94 ° C.).

The content of the (meth) acrylic compound having a hydrophobic group is preferably 10 to 30% by mass, more preferably 15 to 25% by mass with respect to the total mass of the composition.

(Crosslinking agent)
The composition of the present invention preferably further contains a crosslinking agent.
In the present invention, the crosslinking agent is not particularly limited as long as it is a compound having two or more ethylenically unsaturated groups in one molecule, and one having two is exemplified. The ethylenically unsaturated group is the same as described above. The ethylenically unsaturated group can be bonded to an organic group. As an organic group, the thing similar to the organic group which the compound which has a hydrophilic group and an ethylenically unsaturated group can have is mentioned, for example.

As a crosslinking agent, for example,
Ethylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, nonanediol di (meth) acrylate, Trans-1,4-cyclohexanediol di (meth) acrylate, polyethylene glycol di (meth) acrylate, di (meth) acrylate such as polypropylene glycol di (meth) acrylate; trimethylolpropane tri (meth) acrylate, pentaerythritol tri Tri (meth) acrylate such as (meth) acrylate; 4- to 5-functional (meth) acrylate such as pentaerythritol tetra (meth) acrylate and dipentaerythritol hexa (meth) acrylate DOO; polyfunctional (meth) acrylamide.

Of these, di (meth) acrylate and polyfunctional (meth) acrylamide are preferable, and polyfunctional acrylamide is more preferable.
Examples of the di (meth) acrylate include polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, and pentaerythritol tri (meth) acrylate. Among these, di (meth) acrylate is preferably triethylene glycol diacrylate (TEGDAA) or triethylene glycol dimethacrylate (TEGDMA).

Polyfunctional acrylamide is a compound having a plurality of acrylamide bonds (CH ₂ ═CH—CO—NH—) in one molecule. The number of acrylamide bonds in one molecule of polyfunctional acrylamide is preferably 2-4.

Examples of the polyfunctional acrylamide include polymerizable compounds 1 to 12 described in Paragraph <0031> of Paragraph <0031> of the Japan Society for Invention and Technology (Publication No. 2013-502654, published on August 27, 2013), Paragraph < And polyfunctional compounds 1 to 11 described below, and the following compounds 3 to 6.

Moreover, as polyfunctional acrylamide, for example,
Polymerizable compound 1 described in paragraph <0031> of a polyfunctional acrylamide that is water-soluble and solid at 20 ° C. (for example, Publication No. 2013-502654, issued on August 27, 2013, Invention Promotion Association) To 12, polyfunctional compounds 1 to 11) according to paragraph <0192>;
Polyfunctional acrylamide that is water-soluble and liquid at 20 ° C. (for example, the above compounds 3 to 6 are mentioned. Synthesis examples of compounds 3 to 6 are described in the examples);
Examples include water-insoluble water-soluble polyfunctional acrylamide (eg, methylenebisacrylamide) under the condition of 20 ° C.
When water-soluble and liquid polyfunctional acrylamide is used under the condition of 20 ° C. as the crosslinking agent, the tackiness can be further improved.

In the present invention, the polyfunctional acrylamide is water-soluble. When the polyfunctional acrylamide is dissolved in water at room temperature (20 ° C.), the polyfunctional acrylamide in an amount of 10% by mass or more of water is dissolved in water. It means to do.
The term “poorly water-soluble polyfunctional acrylamide” means that when polyfunctional acrylamide is dissolved in water at room temperature (20 ° C.), polyfunctional acrylamide in an amount of less than 10% by mass of water dissolves in water.
The crosslinking agents can be used alone or in combination of two or more.

The content of the crosslinking agent is preferably 0.1 to 10% by mass relative to the total mass of the composition.

(Additive)
The said composition may further contain components (additives) other than the component mentioned above as needed.
As such components, for example, a compound having a hydrophilic group and an ethylenically unsaturated group, a (meth) acrylic compound having a hydrophobic group, and a polymerizable monomer other than the content of a crosslinking agent, a tackifier, Photopolymerization initiators other than the compounds represented by the general formula (I), chain transfer agents, solvents, sensitizing dyes, polymerization inhibition inhibitors, surface lubricants, leveling agents, antioxidants, corrosion inhibitors, light Examples of the additives include stabilizers, ultraviolet absorbers, polymerization inhibitors, silane coupling agents, inorganic or organic fillers, powders such as metal powders and pigments, particulates, and foils. The kind and content of the additive can be appropriately selected according to the use for which various conventionally known additives are used.

In order that the composition of this invention may maintain the outstanding adhesiveness, it is mentioned as one of the preferable aspects that it does not contain water substantially.
In the present invention, “substantially not containing water” means that the content of water is 1% by mass or less based on the total mass of the composition. The water content of the composition of the present invention is preferably 0% by mass.

The composition of the present invention is not particularly limited for its production, and a known method can be adopted. For example, after mixing each said component, it can prepare by stirring by a well-known means.

An adhesive can be produced by curing the composition of the present invention. The form of the adhesive is not particularly limited. An example is a sheet.

[Adhesive sheet]
The pressure-sensitive adhesive sheet of the present invention can be obtained by irradiating the active energy ray-curable pressure-sensitive adhesive composition of the present invention with active energy rays.

The method for curing the composition is not particularly limited. For example, the composition is applied onto a predetermined substrate (for example, a release film such as release polyethylene terephthalate (release PET)) and irradiated with light. The method of photocuring is mentioned.
An adhesive sheet can be provided on one or both sides of the substrate. Or a base material can be provided in the single side | surface or both surfaces of an adhesive sheet.

The active energy ray may be appropriately set according to the purpose, and includes rays such as far ultraviolet rays, ultraviolet rays, near ultraviolet rays, infrared rays, electromagnetic waves such as X-rays and γ rays, electron beams, proton rays, neutron rays, and the like. Ultraviolet rays are preferable from the viewpoints of curing speed, availability of an irradiation device, price, and the like.
For the ultraviolet irradiation, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, a chemical lamp, an electrodeless discharge lamp, an ultraviolet LED, or the like that emits light in a wavelength range of 150 to 450 nm can be used.
Examples of the method for applying the composition include a gravure coater, a comma coater, a bar coater, a knife coater, a die coater, and a roll coater.
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 1 to 10 J / cm ² .
After forming the pressure-sensitive adhesive sheet, if necessary, a release film such as a release PET film may be laminated on the exposed surface of the formed pressure-sensitive adhesive sheet.

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.

Applications of the pressure-sensitive adhesive sheet of the present invention include, for example, optical pressure-sensitive adhesives for capacitive touch panels and pressure-sensitive adhesives for polarizing plates, medical tapes such as bandages and suture tapes, and moisture-permeable waterproofing for construction. Tape, etc.

The lamination method for laminating the pressure-sensitive adhesive sheet of the present invention on a substrate is not particularly limited, and examples thereof include a method of providing a pressure-sensitive adhesive sheet on a release film and using this to transfer the pressure-sensitive adhesive sheet to the substrate. It is done. After the transfer, the release film may be removed from the adhesive sheet. The release film may remain attached.

Examples of release film materials include paper, polyethylene, polypropylene, synthetic resin films such as polyethylene terephthalate, rubber sheets, paper, cloth, non-woven fabrics, nets, foam sheets and metal foils, and appropriate thin leaves such as laminates thereof. Can be given. In order to improve the peelability of the pressure-sensitive adhesive sheet, the surface of the release film may be subjected to a low adhesion release treatment such as silicone treatment, long-chain alkyl treatment, and fluorine treatment as necessary.

[Laminate for touch panel, capacitive touch panel]
The laminated body for touchscreens of this invention is equipped with the adhesive sheet of this invention, 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.

The capacitive touch panel of the present invention is
A display device, the pressure-sensitive adhesive sheet of the present invention, and a capacitive touch panel sensor are provided 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 arranged 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). This 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.

<Synthesis Example 1: Production of Compound (Compound 1) Represented by General Formula (I)>
(Synthesis of Intermediate 1)

97.2 g (0.95 mol) of acetic anhydride was added dropwise to 170.0 g of phenyldiglycol (PhDG, manufactured by Nippon Emulsifier) (0.93 mol) heated to 90 ° C., and the mixture was heated and stirred at 120 ° C. for 6 hours. Thereafter, the mixture was concentrated under reduced pressure to obtain 204.4 g of Intermediate 1 (yield 98%).

(Synthesis of Intermediate 2)

120.0 g of aluminum (III) chloride (0.90 mol) was added to 270 mL of o-dichlorobenzene (DCB) (2.39 mol), and the mixture was cooled to 0 ° C. To this, 44.26 mL of 2-bromoisobutyric acid bromide (0.36 mol) was added dropwise and stirred for 15 minutes. Thereafter, 67.28 g of Intermediate 1 (0.30 mol) was added dropwise over 30 minutes while maintaining the temperature of the reaction solution at 0 ° C. The reaction solution after the dropping was returned to room temperature (22 ° C.) and stirred for 2 hours. Thereafter, the reaction solution was added in several portions to 300 mL of water cooled to 5 ° C. The organic phase was washed twice with 300 ml of water, further washed with 135 mL of sodium bicarbonate solution and 135 mL of saturated brine, 300 mL of water was added to the organic phase, and azeotropic concentration was performed under reduced pressure to obtain 110.8 g of Intermediate 2. (Yield 95%).

(Synthesis of Compound 1)

100.0 g of Intermediate 2 (0.27 mol) was dissolved in 200 mL of isopropanol, and 214 g of 25% by mass aqueous sodium hydroxide solution was added dropwise and stirred for 2 hours. Thereafter, stirring was stopped, and the organic phase was washed twice with a saturated saline solution and then neutralized with hydrochloric acid. After the organic phase was concentrated under reduced pressure, 72 mL of methyl ethyl ketone was added, and the precipitated salt was filtered. The filtrate was concentrated under reduced pressure, 72 mL of water was added, and azeotropic concentration was performed under reduced pressure to obtain 56.8 g of Compound 1 (yield 87%). Compound 1 was liquid at 23 ° C.

<Synthesis Example 2: Production of Compound (Compound 2) Represented by General Formula (I)>
Compound 2 was synthesized in the same manner as in Synthesis Example 1 except that the phenyl diglycol of Synthesis Example 1 was replaced with hexaethylene glycol monophenyl ether. Compound 2 was liquid at 23 ° C.

<Preparation of crosslinking agent>
Synthesis Example of Compound 3 In a 2 L three-necked flask equipped with a stirrer, 30 g of N- (2-aminoethyl) -1,3-propanediamine (manufactured by Aldrich) was first added and 301 g of NaHCO ₃ (N- (2-amino) (Ethyl) -1,3-propanediamine had 14 equivalents to —NH ₂ group), 1 L of dichloromethane and 50 ml of water were placed, and the three-necked flask was placed in an ice bath. Next, 232 g of acrylic acid chloride (10 equivalents relative to the —NH ₂ group, manufactured by Wako Pure Chemical Industries, Ltd.) was dropped into the three-necked flask over 3 hours, and then stirred at room temperature for 3 hours. After confirming disappearance of the raw materials by ¹ H-NMR, the solvent of the reaction mixture was distilled off under reduced pressure, the reaction mixture was dried over magnesium sulfate, filtered through celite, and the solvent was distilled off under reduced pressure. Finally, purification by silica column chromatography (a mixed solvent of ethyl acetate and methanol with a volume ratio of 9: 1 was used as a developing solvent) gave Compound 3 (43% yield) having the above structure. It was. Compound 3 was liquid at normal temperature (20 ° C. condition). Compound 3 was water soluble.

Synthesis example of compound 4 The same as the synthesis example of compound 3, except that N- (2-aminoethyl) -1,3-propanediamine was replaced with bis (3-aminopropyl) amine (manufactured by Tokyo Chemical Industry Co., Ltd.) The compound 4 having the above structure was obtained (43% yield). Compound 4 was liquid at room temperature (20 ° C. condition). Compound 4 was water soluble.

Synthesis Example of Compound 5 Compound 3 except that N- (2-aminoethyl) -1,3-propanediamine was replaced with N, N′-bis (3-aminopropyl) ethylenediamine (manufactured by Tokyo Chemical Industry Co., Ltd.) The compound 5 (yield 40%) having the above structure was prepared in the same manner as in the above synthesis example. Compound 5 was liquid at room temperature (20 ° C. condition). Compound 5 was water soluble.

Synthesis example of compound 6 N- (2-aminoethyl) -1,3-propanediamine was replaced with N, N′-bis (2-aminoethyl) -1,3-propanediamine (manufactured by Tokyo Chemical Industry Co., Ltd.) Except for the above, preparation was carried out in the same manner as in the synthesis example of compound 3, to obtain compound 6 having the above structure (yield 41%). Compound 6 was liquid at room temperature (20 ° C. condition). Compound 6 was water soluble.

<Manufacture of active energy ray-curable pressure-sensitive adhesive composition>
(Examples 1 to 17, Comparative Examples 1 and 2)
The components shown in Table 2 below were mixed in the blending amounts (% by mass) shown in Table 2 below and stirred to obtain active energy ray-curable pressure-sensitive adhesive compositions (base compositions).
For example, in the active energy ray-curable pressure-sensitive adhesive composition of Example 1, compound 1 (5 parts by mass), HEA (75 parts by mass), BA (19 parts by mass), and TEGDMA (1 part by mass) are mixed. And an active energy ray-curable pressure-sensitive adhesive composition obtained by stirring. Details of each component are as described below.

<Manufacture of adhesive sheet>
The active energy ray-curable pressure-sensitive adhesive composition produced as described above is placed on a release PET film (release-treated polyethylene terephthalate film, trade name: Diafoil, manufactured by Mitsubishi Plastics, length 30 cm, width 21 cm, thickness 80 μm). A pressure-sensitive adhesive composition layer is formed by coating the entire surface of the pressure-sensitive adhesive composition layer, and another pressure-sensitive adhesive PET layer as described above is attached onto the pressure-sensitive adhesive composition layer, and the pressure-sensitive adhesive composition layer sandwiched between the release PET films is formed. Formed. Next, the adhesive composition layer sandwiched between the release PET films is irradiated with a fusion UV lamp (D bulb: illuminance 200 mW / cm ² ) under the condition of 1 J / cm ² , cured, and then released with the release PET film. A sandwiched adhesive sheet (thickness of the adhesive sheet only: 150 μm) was obtained.

(Quantification of residual monomer)
About 30 mg of the composition before curing obtained in each Example and Comparative Example was added to 10 mL of a mixed solvent of tetrahydrofuran and acetonitrile having a mass ratio of 5: 5 and stirred for 1 hour at 25 ° C. The residual monomer was extracted.
Further, the pressure-sensitive adhesive sheet (the release film is removed) after being cured as described above is cut into a size of 5 mm × 30 mm in length and width, and this is mixed with 10 mL of a mixed solvent having a mass ratio of tetrahydrofuran and acetonitrile of 5: 5. In addition to the above, the mixture was stirred for 1 hour at 25 ° C., and the residual monomer in the pressure-sensitive adhesive sheet was extracted.
Liquid chromatography was measured using each of the extracts obtained as described above.
After converting the concentration, “monomer peak area of the pressure-sensitive adhesive sheet / monomer peak area of the composition” was calculated with respect to the peak area of each monomer, and the value of the residual monomer% was obtained.
The evaluation was made according to the following criteria. Practically, A or B is preferable.
“A”: The residual monomer was less than 10%.
“B”: The residual monomer was 10% or more and less than 20%.
“C”: The residual monomer was 20% or more.
In addition, the said monomer is the compound (henceforth a "hydrophilic monomer" in Table 2) which has a hydrophilic group and an ethylenically unsaturated group used for each Example and the comparative example, and has a hydrophobic group (meta). ) An acrylic compound (hereinafter, “hydrophobic monomer” in Table 2) and a concept including all of the crosslinking agent, and the residual monomer is also a concept including the residue of three monomers. The compound represented by general formula (I) is not included in the residual monomer. The peak in the liquid chromatography of the compound represented by the general formula (I) does not overlap with the peak of the residual monomer.

(Adhesive strength before high temperature test)
The pressure-sensitive adhesive sheets obtained in each Example and Comparative Example were cut into 2.5 cm × 5 cm, the release film was peeled off, one side of the obtained pressure-sensitive adhesive sheet was placed on a glass substrate (50 mm × 75 mm), and the other side was A sample attached to a Kapton film (trade name: Kapton 200H / V, manufactured by Toray DuPont Co., Ltd., thickness 50 μm) was prepared. Subsequently, using an autograph manufactured by Shimadzu Corporation, one end of a Kapton film parallel to the 2.5 cm width direction of the pressure-sensitive adhesive sheet was gripped, and a 180-degree peel test (tensile speed) at 25 ° C. and 50% RH. 300 cm / min), the average test force value of the pressure-sensitive adhesive sheet and the glass substrate was measured, and this value was defined as the adhesive strength (N / mm). The evaluation was made according to the following criteria. Practically, A or B is preferable.
“A”: Adhesive strength was 0.7 N / mm or more.
“B”: The adhesive strength was 0.4 N / mm or more and less than 0.7 N / mm.
“C”: Adhesive strength was less than 0.4 N / mm.

(Adhesive strength after high temperature test)
The sample (a laminated body of a glass substrate, an adhesive sheet and a Kapton film) produced as described above was stored for 10 days under the conditions of 85 ° C. and 20% RH. Next, after leaving at room temperature for 60 minutes, the adhesive strength was measured and evaluated in the same manner as before the high temperature test. The evaluation criteria are the same as before the high temperature test.

(Haze value evaluation before high humidity test)
The two release films are peeled from the adhesive sheet sandwiched between the release PET films produced as described above, and one side of the resulting adhesive sheet is attached to a glass substrate (50 mm x 75 mm), Murakami Color Technology A haze value was evaluated under the conditions of 25 ° C. and 50% RH with respect to the pressure-sensitive adhesive sheet attached to the glass substrate using HR-100 type manufactured by Research Laboratory. The evaluation criteria for the haze value are as follows. Practically, A or B is preferable. In addition, the haze value before the high humidity test of only the glass substrate was 0.01%.
“A”: Haze was less than 0.5%.
“B”: Haze was 0.5% or more and less than 1%.
“C”: Haze was 1% or more.

(Haze value evaluation after high humidity test)
The pressure-sensitive adhesive sheet sandwiched between the release PET films used in the haze value evaluation before the high humidity test was stored for 1 day under the conditions of 60 ° C. and 90% RH. Then, it returned to room temperature over 30 minutes, it affixed on the glass substrate immediately like the high humidity test, and measured and evaluated the haze value. The evaluation criteria are the same as before the high humidity test.

(Evaluation of composition stability before low temperature aging)
About each composition obtained by each Example and the comparative example, the presence or absence of solid precipitation was confirmed visually. Practically, it is preferable that there is no precipitation.

(Evaluation of composition stability after low temperature aging)
Each composition obtained in each Example and Comparative Example was stored at −20 ° C. for 3 weeks. Then, the presence or absence of solid precipitation was confirmed visually. Practically, it is preferable that there is no precipitation.

<Comprehensive evaluation>
Each composition and adhesive sheet obtained in each Example and Comparative Example were comprehensively evaluated. The evaluation criteria are as follows. Practically, A or B is preferable.
"A": Evaluation is "A" in any of the items of adhesive strength before high temperature test, adhesive strength after high temperature test, haze value evaluation before high humidity test, and haze value evaluation after high humidity test When there is no precipitation before and after low temperature aging, “B”: adhesive strength before high temperature test, adhesive strength after high temperature test, haze value evaluation before high humidity test, and high humidity test In any item of the later haze value evaluation, the evaluation “B” is included, the evaluation of any item is “B” or more, and there is no precipitation before and after the low temperature aging. "C": Evaluation "C" is included in any of the items of adhesive strength before high temperature test, adhesive strength after high temperature test, haze value evaluation before high humidity test, and haze value evaluation after high humidity test. Or before low temperature aging and after low temperature aging If there is precipitation in Zureka

In Table 2, the content (wt%) of each component represents the content (mass%) of each component in the active energy ray-curable pressure-sensitive adhesive composition.

[Supplement under rule 26 30.09.2015]

The detail of each component described in Table 2 is as follows.
Compounds 1, 2, ... Compounds prepared as described above. The structural formula is shown below.
・ Irg. 2959 ... Irgacure 2959 (1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one). Made by Ciba Specialty Chemicals. The structural formula is shown below.
Compounds 1 and 2 correspond to the compounds represented by the general formula (I) described above. 2959 does not correspond to the compound represented by the general formula (I).

-HEA ... 2-ethylhexyl acrylate. The structural formula is shown below.
-AA ... acrylic acid. The structural formula is shown below.
・ NVP: N-vinylpyrrolidone. The structural formula is shown below.

BA ... n-butyl acrylate. The structural formula is shown below. Glass transition temperature of homopolymer of n-butyl acrylate: -50 ° C
-IBXA ... isobornyl acrylate. The structural formula is shown below. Glass transition temperature of homopolymer of isobornyl acrylate: 94 ° C

-TEGDMA-Triethylene glycol dimethacrylate-Compounds 3-6-Compounds prepared as described above-MBA-Methylenebisacrylamide (poorly water-soluble solid crosslinking agent)

As can be seen from Table 2, the compositions of Examples have no precipitation before and after low temperature aging, and the compounds represented by the general formula (I) are excellent in compatibility. By this, the composition of this invention can contain many compounds represented by general formula (I).
The pressure-sensitive adhesive sheet of the example had little residual monomer and was excellent in adhesiveness before the high temperature test. Moreover, adhesiveness was maintained before and after the high temperature test, or the fall of adhesiveness was suppressed.
The adhesive sheet of the example had low haze before the high humidity test. Moreover, the haze was maintained before and after the high humidity test, or the raise of the haze was suppressed.

From the comparison with Examples 2 and 3, the combination of the compound having a hydrophilic group and an ethylenically unsaturated group was more hydroxy than the combination of the hydroxy group-containing (meth) acrylate and the amide compound (Example 3). The combination of the group-containing (meth) acrylate and (meth) acrylic acid (Example 2) was superior in tackiness.

From the comparison with Examples 1 and 8, as the compound represented by the general formula (I), it is more sticky to use Compound 1 (Example 1) than to use Compound 2 (Example 8). Better.
From the comparison with Examples 4 to 7, when the content of the compound represented by the general formula (I) was 2 to 7% by mass with respect to the total mass of the composition, the adhesiveness was more excellent.
From comparison between Example 1 and Examples 9 and 10, when the amount of the (meth) acrylic compound having a hydrophobic group is 10 to 30% by mass in the composition (Example 1), It was more excellent in tackiness than Examples 9 and 10 which were out of range.
From comparison between Example 1 and Example 11, when the glass transition temperature of the homopolymer of the (meth) acrylic compound having a hydrophobic group is -80 ° C to + 20 ° C (Example 1), it is out of this range. The adhesiveness was superior to that of Example 11.
From a comparison between Example 1 and Example 12, when the composition did not contain water (Example 1), it was superior in tackiness to Example 12 containing water.

Comparing Examples 13 to 17 with respect to the cross-linking agent, Examples 13 to 16 containing the compounds 3 to 6 are more adhesive than the Example 17 containing MBA (methylenebisacrylamide), and have higher adhesiveness and higher humidity after the high temperature test. The haze value after the test was more excellent. This is presumably because the compounds 3 to 6 are water-soluble and liquid at 20 ° C., so that they have excellent compatibility with the compound represented by the general formula (I) and high reactivity. On the other hand, when MBA is used, MBA is poorly water-soluble and solid at 20 ° C., so the compatibility and reactivity with the compound represented by the general formula (I) are lower than those of compounds 3 to 6, and therefore high In addition to the deterioration of the haze value after the wet test, the adhesive strength is also low, and it is considered that the overall evaluation B was obtained.
Further, when Example 1 and Examples 13 to 16 were compared with respect to the crosslinking agent, Examples 13 to 16 containing compounds 3 to 6 were more excellent in adhesiveness than Example 1 containing TEGDMA.

On the other hand, Comparative Example 2 containing a compound (polymerization initiator) other than the compound represented by the general formula (I) without containing the compound represented by the general formula (I) has a large amount of residual monomer, and has a high temperature. The tackiness before the test was low, and the tackiness after the high temperature test was further deteriorated than before the high temperature test. The haze after the high humidity test of the pressure-sensitive adhesive sheet of Comparative Example 2 was higher than that before the high humidity test. In Comparative Example 2, precipitation occurred after low temperature aging.
Comparative Example 1 in which the amount of the compound (polymerization initiator) other than the compound represented by the general formula (I) was larger than that in Comparative Example 2 was low in adhesiveness after the high-temperature test and worse than that before the high-temperature test. Further, Comparative Example 1 had a high haze before the high humidity test, and the haze after the high humidity test was further deteriorated than before the high humidity test. In Comparative Example 1, precipitation occurred before and after low temperature aging.

<Application to capacitive touch panel>
(Evaluation of capacitive touch panel)
The manufacturing method of the touch panel used by evaluation of adhesiveness and visibility is shown below.

(Preparation of silver halide emulsion)
To the following 1 liquid maintained at 38 ° C. and pH 4.5, an amount corresponding to 90% of each of the following 2 and 3 liquids was simultaneously added over 20 minutes while stirring to form 0.16 μm core particles. Subsequently, the following 4 liquid and 5 liquid were added over 8 minutes, and the remaining 10% of the following 2 liquid and 3 liquid were further added over 2 minutes to grow particles to 0.21 μm. Further, 0.15 g of potassium iodide was added and ripened for 5 minutes to complete the grain formation.

1 liquid:
750 ml of water
9g gelatin
Sodium chloride 3g
1,3-Dimethylimidazolidine-2-thione 20mg
Sodium benzenethiosulfonate 10mg
Citric acid 0.7g
Two liquids:
300 ml of water
150 g silver nitrate
3 liquids:
300 ml of water
Sodium chloride 38g
Potassium bromide 32g
Potassium hexachloroiridium (III) (0.005% KCl 20% aqueous solution) 8 ml
Ammonium hexachlororhodate (0.001% NaCl 20% aqueous solution) 10 ml
4 liquids:
100ml water
Silver nitrate 50g
5 liquids:
100ml water
Sodium chloride 13g
Potassium bromide 11g
Yellow blood salt 5mg

Then, it was washed with water by a flocculation method according to a conventional method. Specifically, the temperature was lowered to 35 ° C., and the pH was lowered using sulfuric acid until the silver halide precipitated (the pH was in the range of 3.6 ± 0.2). Next, about 3 liters of the supernatant was removed (first water washing). Further, 3 liters of distilled water was added, and sulfuric acid was added until the silver halide settled. Again, 3 liters of the supernatant was removed (second water wash). The same operation as the second water washing was further repeated once (third water washing) to complete the water washing / desalting step. The emulsion after washing with water and desalting was adjusted to pH 6.4 and pAg 7.5, and gelatin 3.9 g, sodium benzenethiosulfonate 10 mg, sodium benzenethiosulfinate 3 mg, sodium thiosulfate 15 mg and chloroauric acid 10 mg were added. Chemical sensitization to obtain optimum sensitivity at 0 ° C., 100 mg of 1,3,3a, 7-tetraazaindene as stabilizer and 100 mg of proxel (trade name, manufactured by ICI Co., Ltd.) as preservative It was. The finally obtained emulsion contains 0.08 mol% of silver iodide, and the ratio of silver chlorobromide is 70 mol% of silver chloride and 30 mol% of silver bromide. It was a silver iodochlorobromide cubic grain emulsion having a coefficient of 9%.

(Preparation of photosensitive layer forming composition)
1,3,3a, 7-tetraazaindene 1.2 × 10 ⁻⁴ mol / mol Ag, hydroquinone 1.2 × 10 ⁻² mol / mol Ag, citric acid 3.0 × 10 ⁻⁴ mol / Mole Ag and 2,4-dichloro-6-hydroxy-1,3,5-triazine sodium salt (0.90 g / mole Ag) were added, and the pH of the coating solution was adjusted to 5.6 using citric acid, and photosensitivity was achieved. A composition for forming a conductive layer was obtained.

(Photosensitive layer forming step)
After subjecting a polyethylene terephthalate (PET) film having a thickness of 100 μm to corona discharge treatment, a gelatin layer having a thickness of 0.1 μm as an undercoat layer on both sides of the PET film, and an optical density of about 1.0 on the undercoat layer. And an antihalation layer containing a dye which is decolorized by alkali in the developer. On the antihalation layer, the composition for forming a photosensitive layer was applied, a gelatin layer having a thickness of 0.15 μm was further provided, and a PET film having a photosensitive layer formed on both sides was obtained. The obtained film is referred to as film A. The formed photosensitive layer had a silver amount of 6.0 g / m ² and a gelatin amount of 1.0 g / m ² .

(Exposure development process)
Parallel using a high-pressure mercury lamp as a light source through a photomask in which detection electrodes (first detection electrode and second detection electrode) and lead-out wiring (first lead-out wiring and second lead-out wiring) are arranged on both surfaces of the film A. Exposure was performed using light. After the exposure, development was performed with a developing solution, and further development processing was performed using a fixing solution (trade name: N3X-R for CN16X, manufactured by FUJIFILM Corporation). Furthermore, by rinsing with pure water and drying, a capacitive touch panel sensor A provided with detection electrodes and lead wires made of Ag fine wires on both sides was obtained.
In the obtained capacitive touch panel sensor A, the detection electrodes are composed of conductive thin wires that intersect in a mesh shape. Further, as described above, the first detection electrode is an electrode extending in the X direction, and the second detection electrode is an electrode extending in the Y direction, and each is disposed on the film at a pitch of 4.5 to 5 mm.

Next, a touch panel including a liquid crystal display device, a lower adhesive layer, a capacitive touch panel sensor, an upper adhesive layer, and a glass substrate in this order was manufactured using the adhesive sheets obtained in the examples and comparative examples. In addition, as a capacitive touch panel sensor, the capacitive touch panel sensor A manufactured above was used.
Specifically, the adhesive sheet (having the release PET on one side) and the capacitive touch panel sensor A, the surface of the adhesive sheet opposite to the surface having the release PET and one of the capacitive touch panel A The upper adhesive layer was formed by pasting using a 2 kg heavy roller so that the surface of the upper surface would face. Furthermore, the release PET of the pressure-sensitive adhesive sheet was peeled off, and a glass substrate of the same size was bonded onto the upper pressure-sensitive adhesive layer in the same manner using a 2 kg heavy roller. Then, it was exposed to the environment of 40 degreeC and 5 atmospheres for 20 minutes in the high-pressure thermostat, and the defoaming process was performed.
Next, following the same procedure as the formation of the upper adhesive layer, an adhesive sheet (having a release PET on one side) is bonded to the surface opposite to the surface on which the upper adhesive layer of the capacitive touch panel A is formed, A lower adhesive layer was formed. Furthermore, the release PET of the pressure-sensitive adhesive sheet was peeled off, and a liquid crystal display device was attached on the lower pressure-sensitive adhesive layer. Then, it was exposed to the environment of 40 degreeC and 5 atmospheres for 20 minutes in the high-pressure thermostat, and the defoaming process was performed. Thus, the touch panel was manufactured.
The size in the diagonal direction of the touch part (sensing part) in the capacitive touch panel sensor was 5 inches.

Capacitive touch panels using the pressure-sensitive adhesive sheets of Examples 1 to 17 exhibited excellent adhesion and visibility.
On the other hand, in the pressure-sensitive adhesive sheet of Comparative Example 1, the brightness of the screen was not uniform and unclear, and the visibility was further deteriorated in a high humidity environment.
Further, in the pressure-sensitive adhesive sheet of Comparative Example 2, since the adhesive force was insufficient, peeling of other members was remarkable, and it became easier to peel off after aging in a high temperature environment.

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 (13)

1. An active energy ray-curable pressure-sensitive adhesive composition comprising a compound having a hydrophilic group and an ethylenically unsaturated group and a compound represented by the following general formula (I).
   

   

   
   In general formula (I), V ¹ , V ² , V ³ , and V ⁴ each independently represent a hydrogen atom or a substituent. In general formula (I), n represents an integer of 1 or more and 5 or less.
2. The active energy ray-curable pressure-sensitive adhesive composition according to claim 1, wherein n is 1 in the general formula (I).
3. The active energy ray-curable pressure-sensitive adhesive composition according to claim 1 or 2, wherein the compound having a hydrophilic group and an ethylenically unsaturated group is a (meth) acrylic compound.
4. The content of the compound represented by the general formula (I) is 1 to 10% by mass with respect to the total mass of the active energy ray-curable pressure-sensitive adhesive composition. The active energy ray-curable pressure-sensitive adhesive composition described in 1.
5. Furthermore, a (meth) acrylic compound having a hydrophobic group is included,
   The content of the (meth) acrylic compound having a hydrophobic group is 10 to 30% by mass with respect to the total mass of the active energy ray-curable pressure-sensitive adhesive composition. The active energy ray-curable pressure-sensitive adhesive composition according to Item.
6. The active energy ray-curable pressure-sensitive adhesive composition according to claim 5, wherein a glass transition temperature of the homopolymer of the (meth) acrylic compound having a hydrophobic group is -80 ° C to + 20 ° C.
7. The active energy ray-curable pressure-sensitive adhesive composition according to any one of claims 1 to 6, further comprising a crosslinking agent, wherein the crosslinking agent contains at least polyfunctional acrylamide.
8. The active energy ray-curable pressure-sensitive adhesive composition according to claim 7, wherein the polyfunctional acrylamide is at least one selected from the group consisting of the following compounds 3 to 6.
   

   
9. The active energy ray-curable pressure-sensitive adhesive composition according to claim 7 or 8, wherein the content of the crosslinking agent is 0.1 to 10% by mass with respect to the total mass of the active energy ray-curable pressure-sensitive adhesive composition. object.
10. 10. The active energy ray-curable pressure-sensitive adhesive composition according to any one of claims 1 to 9, which is substantially free of water.
11. A pressure-sensitive adhesive sheet obtained by irradiating the active energy ray-curable pressure-sensitive adhesive composition according to any one of claims 1 to 10 with active energy rays.
12. A laminate for a touch panel, comprising the pressure-sensitive adhesive sheet according to claim 11 and a capacitive touch panel sensor.
13. A capacitive touch panel comprising the display device, the adhesive sheet according to claim 11, and a capacitive touch panel sensor in this order.

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