KR20180022685A - Adhesive composition, adhesive, adhesive sheet and display element - Google Patents

Abstract

A pressure-sensitive adhesive composition for forming a pressure-sensitive adhesive for bonding a first display body constituting member and a second display body constituting member having stepped surfaces on at least a side to be conjugated, wherein the first display body constituting member and / (A) and a silane coupling agent (B) having a mercapto group, wherein the adhesive composition has an electrode at least on the side to be conjugated, and the adhesive composition comprises a (meth) acrylic acid ester polymer (A) and a silane coupling agent (B) having a mercapto group. According to the pressure-sensitive adhesive obtained from such a sticky composition, the migration in the electrode can be effectively prevented or suppressed.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a pressure-sensitive adhesive composition, an adhesive, a pressure-

The present invention relates to a pressure-sensitive adhesive composition, a pressure-sensitive adhesive and a pressure-sensitive adhesive sheet, which can be used for a display body such as a touch panel, and a display body using them.

In recent mobile electronic devices such as smart phones and tablet terminals, a touch panel is often used as a display. As a touch panel method, there are a resistance film method, a capacitance method, and the like. In such a mobile electronic device, a capacitance method is mainly adopted.

In recent years, the size of a touch panel has been increased. As such an electrode material for a touch panel, a metal electrode on a mesh, for example, a copper electrode or a silver electrode has been studied. However, when a conventional pressure sensitive adhesive is used in contact with a metal electrode, particularly a copper electrode or a silver electrode, ion migration (= electrochemical migration; hereinafter simply referred to as "migration") may occur. Specifically, in the positive electrode, the electrode is dissolved and broken, and in the negative electrode, a dendrite due to precipitation of the positive electrode component is formed and a short circuit occurs.

This migration is particularly likely to occur when a voltage is applied to the electrode under high temperature and high humidity. When such a migration occurs, the touch panel is not normally operated. Particularly, in recent years, as the electrodes are made finer and narrower in pitch, disconnection and short-circuiting of electrodes due to migration are likely to occur.

However, Patent Document 1 discloses a pressure-sensitive adhesive composition for a touch panel, which contains a benzotriazole compound as a rust inhibitor.

Japanese Patent Application Laid-Open No. 2014-177611

However, even if the benzotriazole compound as the rust preventive agent had an effect of preventing the corrosion of the metal wiring, the migration could not be sufficiently prevented or suppressed.

It is an object of the present invention to provide a pressure-sensitive adhesive composition, a pressure-sensitive adhesive, a pressure-sensitive adhesive sheet and a display body, which are effective in preventing and suppressing migration.

In order to achieve the above-mentioned object, first, the present invention is characterized in that: a first display body constituting member having a step on a surface at least to be adhered; and a second display body constituting member having a tackiness for forming a tackifier for bonding the second display body constituting member The composition according to any one of (1) to (3), wherein the first display body constituting member and / or the second display body constituting member has electrodes on at least a surface to be conjugated, and the viscous composition comprises (meth) acrylic acid ester polymer And a silane coupling agent (B) having a mercapto group and a mercapto group (Invention 1).

According to the pressure-sensitive adhesive composition obtained from the pressure-sensitive adhesive composition according to the present invention (Invention 1), particularly, the first display body constituent member and / The migration of the electrode of the sieve member can be effectively prevented and suppressed.

In the above invention (Invention 1), the mercapto group-containing silane coupling agent (B) is preferably a mercapto group-containing oligomer type silane coupling agent (Invention 2).

In the invention (Invention 1 or 2), the mercapto group equivalent of the organosilicon compound constituting the mercapto group-containing silane coupling agent (B) is preferably 100 g / mol or more and 1000 g / mol or less (Invention 3).

In the above invention (Invention 1 to 3), the content of the mercapto group-containing silane coupling agent (B) in the viscous composition is preferably 0.01 to 100 parts by mass of the (meth) acrylic acid ester polymer (A) And more preferably 5 parts by mass or less (Invention 4).

In the above invention (Invention 1 to 4), the (meth) acrylic acid ester polymer (A) preferably contains 3 mass% or more and 35 mass% or less of the hydroxyl group-containing monomer as the monomer unit constituting the polymer (Invention 5).

In the above invention (Invention 1 to 5), it is preferable that the adhesive composition further contains a crosslinking agent (C) (Invention 6).

Secondly, the present invention provides a pressure-sensitive adhesive comprising the pressure-sensitive adhesive composition (Invention 1 to 6) crosslinked (Invention 7).

Thirdly, the present invention provides a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer comprising the pressure-sensitive adhesive (invention 7) (invention 8).

In the above invention (Invention 8), it is preferable that the pressure-sensitive adhesive sheet has two release sheets, and the pressure-sensitive adhesive layer is sandwiched between the release sheets so as to come into contact with the release surfaces of the two release sheets (Invention 9).

Fourthly, the present invention is characterized in that: a first display body constituting member having at least a step on a side to be conjugated; a second display body constituting member; and a first display body constituting member and a second display body constituting member, Wherein the first display body constituting member and / or the second display body constituting member has electrodes on at least a surface to which the pressure-sensitive adhesive layer is adhered, and the pressure-sensitive adhesive layer is the pressure-sensitive adhesive sheet (invention 8 , 9) is provided as a pressure-sensitive adhesive layer (invention 10).

According to the adhesive composition, the pressure-sensitive adhesive, the pressure-sensitive adhesive sheet and the display body according to the present invention, migration can be effectively prevented or suppressed.

1 is a cross-sectional view of a pressure-sensitive adhesive sheet according to an embodiment of the present invention.
[Fig. 2] is a sectional view showing a configuration example of a touch panel.
3 is a reference image of an evaluation standard in the evaluation of the anti-migration effect of Test Example 3. Fig.

Hereinafter, embodiments of the present invention will be described.

[Adhesive composition]

(Hereinafter also referred to as " sticky composition (P) ") according to the present embodiment comprises a first display body constituting member having a step on a surface to which at least the side to be conjugate is attached, and a second display body constituting member Wherein the first display body constituting member and / or the second display body constituting member has an electrode at least on the side to be conjugated, wherein the (meth) acrylic acid ester polymer (A) and , And a silane coupling agent (B) having a mercapto group, and preferably further contains a crosslinking agent (C). In the present specification, (meth) acrylic acid ester means both of acrylic acid ester and methacrylic acid ester. Other similar terms are also the same. The term " polymer " includes the concept of " copolymer ". The display body and the display body constituting member will be described later.

When the adhesive composition (P) according to the present embodiment contains a silane coupling agent (B) having a mercapto group, it is possible to prevent the electrode from dissolving in the positive electrode when the adhesive obtained from the adhesive composition (P) And dendrite is prevented from being formed in the negative electrode. In other words, the migration in the electrode is effectively prevented and suppressed (this effect may be referred to as " migration prevention effect "). Thereby, even when the pressure-sensitive adhesive is brought into contact with, for example, a fine-pitch or narrow-pitch electrode, disconnection or short-circuiting of the electrode is prevented. In particular, when the electrode is an electrode of a touch panel, defective operation of the touch panel caused by disconnection or short-circuiting of the electrode is prevented.

Here, the electrode may be a transparent conductive film (including a patterned electrode) made of, for example, a metal electrode made of copper, silver, or the like (including a mesh or a grid), tin-doped indium oxide (ITO) And the like. Among these electrodes, a metal electrode mainly composed of a non-oxidized metal, specifically, a metal electrode made of copper or silver is preferable. The non-oxidized metal has a higher ionization tendency than the metal oxide such as ITO. However, according to the pressure-sensitive adhesive obtained from the pressure-sensitive adhesive composition (P) according to the present embodiment, disconnection or short circuiting of the electrode is effectively prevented.

The pressure-sensitive adhesive layer composed of the pressure-sensitive adhesive composition obtained from the pressure-sensitive adhesive composition (P) containing the silane coupling agent (B) having a mercapto group is preferably a silane coupling agent having a mercapto group B) is present, the adhesiveness to the display body constituting member is high and the step traceability is excellent. Specifically, even when the pressure-sensitive adhesive layer is applied to a display member having a step and exposed to high-temperature and high-humidity conditions for a predetermined time (for example, at 85 ° C and 85% RH for 72 hours) , Peeling, peeling, and the like are suppressed (superior step traceability under high temperature and high humidity conditions is excellent). This suppresses the occurrence of reflection loss of light in the vicinity of the stepped portion, and it is possible to maintain the image quality of the display body satisfactorily.

(1) (Meth) acrylic acid ester polymer (A)

The (meth) acrylic acid ester polymer (A) can exhibit favorable tackiness by containing (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group as the monomer unit constituting the polymer. From this viewpoint, it is preferable that the (meth) acrylic acid ester polymer (A) contains, as the lower limit value, 50 mass% or more of (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group as the monomer unit constituting the polymer By mass, particularly preferably not less than 60% by mass, more preferably not less than 70% by mass. When the (meth) acrylic acid alkyl ester is contained in an amount of 50 mass% or more, the (meth) acrylic acid ester polymer (A) can exert a preferable sticking property. The (meth) acrylic acid ester polymer (A) preferably contains the above-mentioned (meth) acrylic acid alkyl ester as a monomer unit constituting the polymer in an amount of preferably 97 mass% or less, more preferably 90 mass% or less By mass, more preferably not more than 85% by mass. By containing 97 mass% or less of the (meth) acrylic acid alkyl ester, other monomer components can be preferably introduced into the (meth) acrylic acid ester polymer (A).

Examples of the (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (Meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (Meth) acrylate, stearyl (meth) acrylate, stearyl (meth) acrylate, stearyl acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate and adamantyl (meth) acrylate. Among them, From the viewpoint of further improvement, it is preferable that (meth) acrylic acid ester having 4 to 8 carbon atoms in the alkyl group is included. These may be used alone or in combination of two or more. The alkyl group in the (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group means a linear, branched or cyclic alkyl group.

(Meth) acrylic acid alkyl ester having an alkyl group of 1 to 20 carbon atoms, a homomeric polymer having a glass transition temperature (Tg) of more than 0 DEG C (preferably 70 DEG C or more) and a glass transition It is also preferable to use a combination of soft monomers having a temperature (Tg) of 0 占 폚 or lower. This is because, by ensuring tackiness and flexibility by the soft monomer and improving the cohesive force with a hard monomer, it is possible to further improve the step traceability in the display panel (touch panel).

The mass ratio of the hard monomer to the soft monomer is preferably 5:95 to 40:60, and more preferably 20:80 to 30:70.

Examples of the hard monomer include methyl acrylate (Tg 10 ° C), methyl methacrylate (Tg 105 ° C), isobornyl acrylate (Tg 94 ° C), isobornyl methacrylate (Tg 180 ° C) Adamantyl acrylate (Tg 115 占 폚), adamantyl methacrylate (Tg 141 占 폚), and the like. These may be used alone or in combination of two or more.

Among the above hard monomers, methyl acrylate, methyl methacrylate and isobornyl acrylate are preferred from the viewpoint of enhancing the performance of the hard monomer while preventing adverse effects on other properties such as adhesiveness and transparency. From the viewpoint of stickiness, methyl acrylate and methyl methacrylate are more preferable, and methyl methacrylate is particularly preferable.

As the soft monomer, acrylic acid alkyl ester having a linear or branched alkyl group having 2 to 12 carbon atoms is preferably used. For example, 2-ethylhexyl acrylate (Tg - 70 DEG C) and n-butyl acrylate (Tg - 54 DEG C) are preferably used. These may be used alone or in combination of two or more.

The (meth) acrylic acid ester polymer (A) preferably contains a monomer having a reactive functional group as a monomer unit constituting the polymer. The reactive functional group derived from the reactive functional group-containing monomer reacts with a crosslinking agent (C) to be described later, whereby a crosslinked structure (three-dimensional network structure) is formed, and a pressure-sensitive adhesive having a desired cohesive strength is obtained.

(Meth) acrylic acid ester polymer (A) as a monomer unit constituting the polymer is preferably a monomer having a hydroxyl group in the molecule (a hydroxyl group-containing monomer), a monomer having a carboxyl group in the molecule (a monomer having a carboxyl group ), A monomer having an amino group in the molecule (an amino group-containing monomer), and the like. Of these, hydroxyl group-containing monomers having excellent reactivity with the crosslinking agent (C) and excellent anti-wet heat and whitening properties and having a small adverse influence on the electrode are particularly preferable.

Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (Meth) acrylic acid hydroxyalkyl esters such as 3-hydroxybutyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate. Among them, 2-hydroxyethyl (meth) acrylate or (meth) acrylic acid (meth) acrylate is preferable in view of reactivity of the hydroxyl group in the obtained (meth) acrylic acid ester polymer (A) with the crosslinking agent Hydroxybutyl is preferred. These may be used alone or in combination of two or more.

Examples of the carboxyl group-containing monomer include ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid and citraconic acid. Among them, acrylic acid is preferable in view of the reactivity of the carboxyl group in the resulting (meth) acrylic acid ester polymer (A) with the crosslinking agent (C) and the copolymerization with other monomers. These may be used alone or in combination of two or more.

Examples of the amino group-containing monomer include aminoethyl (meth) acrylate and n-butylaminoethyl (meth) acrylate. These may be used alone or in combination of two or more.

The (meth) acrylic acid ester polymer (A) preferably contains a hydroxyl group-containing monomer as a lower limit of 3 mass% or more, particularly preferably 10 mass% or more as a monomer unit constituting the polymer, And more preferably 15 mass% or more. The (meth) acrylic acid ester polymer (A) preferably contains a hydroxyl group-containing monomer as an upper limit of the amount of 35 mass% or less, particularly preferably 30 mass% or less, as the monomer unit constituting the polymer, More preferably 25 mass% or less. When the (meth) acrylic acid ester polymer (A) contains a monomer having a hydroxyl group in the above amount as a monomer unit, a predetermined amount of the hydroxyl group remains in the obtained pressure sensitive adhesive. The hydroxyl group is a hydrophilic group. When such a hydrophilic group is present in a predetermined amount of the pressure-sensitive adhesive, even when the pressure-sensitive adhesive is placed under high temperature and high humidity conditions, compatibility with the water penetrated into the pressure-sensitive adhesive under the high temperature and high humidity conditions is good. As a result, Whitening of the pressure-sensitive adhesive when it is turned is suppressed (excellent anti-wet heat and whitening property).

The degree of inhibition of whitening is preferably 1.0% or less, more preferably 0.9% or less (measured according to JIS K 7136: 2000) of the pressure-sensitive adhesive layer when it is returned to ordinary temperature and humidity after subjected to high temperature and high humidity conditions , More preferably not more than 0.8%. It is also preferable that the pressure-sensitive adhesive layer has a haze value as described above even in the state (normal state). When the haze value is 1.0% or less, the transparency is extremely high and is preferable for optical use.

However, when the hydrophilic group is present in the predetermined amount of the pressure-sensitive adhesive as described above, the pressure-sensitive adhesive easily contains water, and the migration of the electrode is likely to occur in contact with the pressure-sensitive adhesive. However, the adhesive composition (P) according to the present embodiment can effectively prevent or suppress migration of the contacting electrode by containing the silane coupling agent (B) having a mercapto group.

It is preferable that the (meth) acrylic acid ester polymer (A) does not contain a monomer containing a carboxyl group as a monomer unit constituting the polymer, but it is allowed to contain a predetermined amount. Since the carboxyl group is an acid component, migration of the object member is usually a concern. However, the pressure sensitive adhesive relating to this embodiment is obtained from the sticky composition (P) containing the silane coupling agent (B) having a mercapto group, The migration prevention effect can be exhibited. Concretely, it is allowed to contain a carboxyl group-containing monomer as a monomer unit in an amount of 5 mass% or less, preferably 2 mass% or less, in the (meth) acrylic acid ester polymer (A).

The (meth) acrylic acid ester polymer (A) may contain other monomers as monomer units constituting the polymer, if desired. As other monomers, monomers which do not contain a reactive functional group are preferable in order not to interfere with the action of the reactive functional group-containing monomer. Examples of such other monomers include (meth) acrylic acid alkoxyalkyl esters such as (meth) acrylic acid methoxyethyl and (meth) acrylate ethoxyethyl, (meth) acrylic acid N, (Meth) acrylate, (meth) acrylamide, dimethyl acrylamide, vinyl acetate, styrene and the like having a non-cross-linkable tertiary amino group such as N, N-dimethylaminopropyl, and (meth) acryloylmorpholine, . These may be used alone or in combination of two or more.

The polymerization of the (meth) acrylic acid ester polymer (A) may be a random copolymer or a block copolymer.

The lower limit of the weight average molecular weight of the (meth) acrylic acid ester polymer (A) is preferably 200,000 or more, particularly preferably 300,000 or more, and more preferably 400,000 or more. If the lower limit of the weight average molecular weight of the (meth) acrylic acid ester polymer (A) is higher than the lower limit, the pressure sensitive adhesive will have excellent step traceability under high temperature and high humidity conditions. The weight average molecular weight in the present specification is a value in terms of standard polystyrene measured by Gel Permeation Chromatography (GPC).

The upper limit of the weight average molecular weight of the (meth) acrylic acid ester polymer (A) is preferably 1 million or less, particularly preferably 90,000 or less, and more preferably 700,000 or less. If the upper limit of the weight average molecular weight of the (meth) acrylic acid ester polymer (A) is not more than the above value, the pressure sensitive adhesive becomes excellent in step following ability at the time of applying.

 In the adhesive composition (P), the (meth) acrylic acid ester polymer (A) may be used singly or in combination of two or more kinds.

(2) a silane coupling agent (B) having a mercapto group,

The silane coupling agent (B) having a mercapto group is composed of an organosilicon compound having at least one mercapto group and at least one alkoxysilyl group in the molecule. In consideration of the use of the obtained pressure-sensitive adhesive, it is preferable that the mercapto group-having silane coupling agent (B) has light transmittance, for example, substantially transparent.

Specific examples of the silane coupling agent (B) having a mercapto group include mercapto compounds such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, and 3-mercaptopropyldimethoxymethylsilane. A soil-containing low molecular weight silane coupling agent; A mercapto group-containing silane compound such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, and 3-mercaptopropyldimethoxymethylsilane, and a mercapto group-containing silane compound such as methyltriethoxysilane, ethyltriethoxysilane Containing oligomer-type silane coupling agents such as co-condensates of alkyl group-containing silane compounds such as methyltrimethoxysilane and ethyltrimethoxysilane. Among them, a mercapto group-containing oligomer-type silane coupling agent having an excellent migration prevention effect and a good workability is preferable, and a cocondensation product of a mercapto group-containing silane compound and an alkyl group-containing silane compound is particularly preferable. - cocondensates of mercaptopropyltrimethoxysilane and methyltriethoxysilane are preferred. These may be used singly or in combination of two or more kinds.

The lower limit of the mercapto group equivalent of the organosilicon compound constituting the silane coupling agent (B) having a mercapto group is preferably 100 g / mole or more, particularly preferably 120 g / mole or more, more preferably 150 g / Mol or more. By setting the lower limit value as described above, the polarity difference between the silane coupling agent (B) and the (meth) acrylic acid ester polymer (A) can be set within a suitable range and the dispersibility of the silane coupling agent (B) in the adhesive can be made preferable.

The upper limit of the mercapto group equivalent of the organosilicon compound constituting the silane coupling agent (B) having a mercapto group is preferably 1000 g / mol or less, more preferably 800 g / mol or less, more preferably 500 g / Or less. By setting the upper limit value as described above, it is possible to prevent deterioration of optical characteristics due to phase separation with the (meth) acrylic acid ester polymer (A).

The content of the mercapto group-containing silane coupling agent (B) in the adhesive composition (P) is preferably 0.01 part by mass or more as a lower limit value relative to 100 parts by mass of the (meth) acrylic acid ester polymer (A) By mass or more, more preferably 0.1 parts by mass or more. The upper limit value is preferably 5 parts by mass or less, more preferably 1.5 parts by mass or less, and further preferably 1.0 part by mass or less. When the content of the silane coupling agent (B) having a mercapto group is within the above range, the migration preventing effect is more excellent.

The lower limit value of the number of moles (mercapto group amount) of the mercapto group in the silane coupling agent (B) per 100 g of the (meth) acrylic acid ester polymer (A) is preferably 0.01 mmol or more, And more preferably 0.2 mmol or more. The upper limit of the number of moles is preferably 30 mmol or less, more preferably 5 mmol or less, further preferably 1.5 mmol or less. When the number of moles of the mercapto group of the silane coupling agent (B) relative to the (meth) acrylic acid ester polymer (A) falls within the above range, the migration preventing effect can be further improved.

(3) Crosslinking agent (C)

The sticky composition (P) preferably contains a cross-linking agent (C). The pressure-sensitive adhesive composition (P) contains a crosslinking agent (C), whereby the (meth) acrylic acid ester polymer (A) is crosslinked to form a three-dimensional network structure to improve the cohesive force of the resulting pressure sensitive adhesive, Can be improved.

The crosslinking agent (C) is not particularly limited as long as it can react with the reactive group of the (meth) acrylic acid ester polymer (A), and examples thereof include isocyanate crosslinking agents, epoxy crosslinking agents, amine crosslinking agents, melamine crosslinking agents, aziridine crosslinking agents, A crosslinking agent, an aldehyde crosslinking agent, an oxazoline crosslinking agent, a metal alkoxide crosslinking agent, a metal chelating crosslinking agent, a metal salt crosslinking agent, and an ammonium salt crosslinking agent. When the (meth) acrylic acid ester polymer (A) contains a hydroxyl group-containing monomer as the monomer unit constituting the polymer, it is preferable to use an isocyanate-based crosslinking agent having excellent reactivity with the hydroxyl group. The crosslinking agent (C) may be used alone or in combination of two or more.

The isocyanate crosslinking agent includes at least a polyisocyanate compound. Examples of the polyisocyanate compound include aromatic polyisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate and xylylene diisocyanate, aliphatic polyisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, hydrogenated diphenylmethane Alicyclic polyisocyanates such as diisocyanate and the like, and reaction products thereof with low-molecular active hydrogen-containing compounds such as burette, isocyanurate, and furthermore, ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, And duct bodies. Among them, trimethylolpropane-modified aromatic polyisocyanates, particularly trimethylolpropane-modified tolylene diisocyanate, are preferable from the viewpoint of reactivity with hydroxyl groups.

The content of the crosslinking agent (C) in the adhesive composition (P) is preferably 0.001 part by mass or more, more preferably 0.01 part by mass or more, as a lower limit value with respect to 100 parts by mass of the (meth) acrylic acid ester polymer (A) More preferably 0.02 parts by mass or more. The upper limit is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and further preferably 1 part by mass or less.

When the content of the crosslinking agent (C) is in the above range, the cohesive force of the obtained pressure sensitive adhesive is preferable, and the step following property of the pressure sensitive adhesive, especially the step following property under high temperature and high humidity conditions, is further improved.

(4) Various additives

To the sticky composition (P), various additives commonly used in acrylic pressure sensitive adhesives such as an antistatic agent, a tackifier, an antioxidant, an ultraviolet absorber, a light stabilizer, a softener, a filler, have. In addition to the above-mentioned silane coupling agent (B) having a mercapto group, other silane coupling agents may be added together. However, the rust preventive agent, particularly the benzotriazole rust preventive agent, has an effect of inhibiting the crosslinking of the adhesive composition (P), and therefore it is preferable not to add it.

The pressure-sensitive adhesive composition (P) refers to a mixture of various components remaining in the pressure-sensitive adhesive layer as it is or remains in the pressure-sensitive adhesive layer. The pressure-sensitive adhesive composition (P) is a component removed by a drying process or the like, Is not included in the sticky composition (P).

(5) Production of sticky composition

The sticky composition (P) is obtained by preparing a (meth) acrylic acid ester polymer (A), mixing the obtained (meth) acrylic acid ester polymer (A) with a mercapto group-containing silane coupling agent May be prepared by adding a cross-linking agent (C) and an additive.

The (meth) acrylic acid ester polymer (A) can be produced by polymerizing a mixture of monomer units constituting the polymer by a conventional radical polymerization method. The polymerization of the (meth) acrylic acid ester polymer (A) can be carried out by a solution polymerization method or the like using a polymerization initiator as desired. As the polymerization solvent, for example, ethyl acetate, n-butyl acetate, isobutyl acetate, toluene, acetone, hexane, methyl ethyl ketone and the like may be used.

Examples of the polymerization initiator include an azo compound, an organic peroxide, and the like, and two or more types may be used in combination. Examples of the azo compound include azo compounds such as 2,2'-azobisisobutyronitrile, 2,2'-azobis (2-methylbutyronitrile), 1,1'-azobis (cyclohexane- (2,4-dimethylvaleronitrile), 2,2'-azobis (2,4-dimethyl-4-methoxy valeronitrile), dimethyl 2,2 ' Azobis (2-methylpropionate), 4,4'-azobis (4-cyanovaleric acid), 2,2'-azobis (2-hydroxymethylpropionitrile) -Azobis [2- (2-imidazolin-2-yl) propane].

Examples of the organic peroxide include organic peroxides such as benzoyl peroxide, t-butyl perbenzoate, cumene hydroperoxide, diisopropyl peroxydicarbonate, di-n-propyl peroxydicarbonate, di (2-ethoxyethyl) Carbonate, t-butyl peroxyneodecanoate, t-butyl peroxypivalate, (3,5,5-trimethylhexanoyl) peroxide, dipropionyl peroxide, and diacetyl peroxide.

In addition, the weight average molecular weight of the resulting polymer can be controlled by blending a chain transfer agent such as 2-mercaptoethanol in the polymerization step.

(Meth) acrylic acid ester polymer (A), a silane coupling agent (B) having a mercapto group and a crosslinking agent (C) may be added to the solution of the (meth) acrylic acid ester polymer And a diluting solvent are added and sufficiently mixed to obtain a sticky composition (P) (coating solution) diluted with a solvent.

Examples of the diluting agent include aliphatic hydrocarbons such as hexane, heptane and cyclohexane, aromatic hydrocarbons such as toluene and xylene, halogenated hydrocarbons such as methylene chloride and ethylene chloride, alcohols such as methanol, ethanol, propanol, Methoxy-2-propanol, ketones such as acetone, methyl ethyl ketone, 2-pentanone, isophorone, and cyclohexanone, esters such as ethyl acetate and butyl acetate, cellosolve solvents such as ethyl cellosolve Etc. are used.

The concentration and viscosity of the coating solution thus prepared are not particularly limited and may be appropriately selected according to the circumstances. For example, it is diluted such that the concentration of the sticky composition (P) is 10 to 40% by mass. In addition, when obtaining the coating solution, it is not necessary to add a diluting solvent or the like, and a diluting solvent may not be added if the viscosity is such that the adhesive composition (P) can be coated. In this case, the adhesive composition (P) becomes a coating solution containing the polymerization solvent of the (meth) acrylic acid ester polymer (A) as it is as a diluent solvent.

[adhesive]

The pressure-sensitive adhesive relating to the present embodiment is obtained by crosslinking the above-mentioned pressure-sensitive adhesive composition (P). The crosslinking of the viscous composition (P) can be carried out by a heat treatment. Further, this heat treatment may also serve as a drying treatment for volatilizing a diluting solvent or the like of the applied pressure-sensitive adhesive composition (P).

When the heat treatment is carried out, the heating temperature is preferably 50 to 150 占 폚, particularly preferably 70 to 120 占 폚. The heating time is preferably 30 seconds to 10 minutes, particularly preferably 50 seconds to 2 minutes. After the heat treatment, if necessary, a curing period of about 1 to 2 weeks may be formed at room temperature (for example, 23 DEG C, 50% RH). When the curing period is required, after the curing period has elapsed, if the curing period is unnecessary, the pressure-sensitive adhesive layer is formed after the heat treatment is completed.

The lower limit value of the gel fraction of the pressure-sensitive adhesive relating to the present embodiment is preferably 30% or more, more preferably 40% or more, further preferably 50% or more. If the lower limit of the gel fraction of the pressure-sensitive adhesive is higher than the above-mentioned range, the cohesive force of the pressure-sensitive adhesive increases and the step following property under high temperature and high humidity conditions is excellent. The upper limit of the gel fraction is preferably 90% or less, more preferably 85% or less, further preferably 80% or less. If the upper limit of the gel fraction of the pressure-sensitive adhesive is less than the above-mentioned range, the pressure-sensitive adhesive is not excessively hardened, and the step-following performance at the time of applying is excellent. Here, the measurement method of the gel fraction of the pressure-sensitive adhesive is as shown in the following test example.

[Adhesive sheet]

1, the pressure-sensitive adhesive sheet 1 according to the present embodiment has a structure in which two release sheets 12a and 12b are brought into contact with the release faces of the two release sheets 12a and 12b, And a pressure-sensitive adhesive layer 11 sandwiched between the two release sheets 12a and 12b. However, the release sheets 12a and 12b in the pressure-sensitive adhesive sheet 1 are not essential components and are peeled and removed when the pressure-sensitive adhesive sheet 1 is used. The release surface of the release sheet in the present specification means a surface having release properties in the release sheet and includes both the surface subjected to the release treatment and the surface exhibiting the release property without performing the release treatment.

(1) Pressure-sensitive adhesive layer

The pressure-sensitive adhesive layer (11) is composed of the above-mentioned pressure-sensitive adhesive. The lower limit of the thickness of the pressure-sensitive adhesive layer 11 (measured in accordance with JIS K 7130) is preferably 10 占 퐉 or more, more preferably 25 占 퐉 or more, and further preferably 50 占 퐉 or more. When the lower limit of the thickness of the pressure-sensitive adhesive layer 11 is the above-mentioned value, excellent adhesive force is sufficiently exhibited. The upper limit of the thickness of the pressure-sensitive adhesive layer 11 is preferably 300 占 퐉 or less, more preferably 250 占 퐉 or less, further preferably 100 占 퐉 or less. When the upper limit of the thickness of the pressure-sensitive adhesive layer 11 is less than or equal to the upper limit, the workability is improved. Further, the pressure-sensitive adhesive layer 11 may be formed as a single layer, or a plurality of layers may be laminated.

(2) Peeling sheet

The release sheets 12a, 12b are not particularly limited, and known plastic films can be used. Examples of the film include polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polyethylene naphthalate film, polybutylene terephthalate (Meth) acrylic acid copolymer film, an ethylene / (meth) acrylic acid ester copolymer film, a polystyrene film, a polycarbonate film, a polyimide film, a fluororesin Film or the like is used. These crosslinked films are also used. Further, these laminated films may be used.

It is preferable that a peeling treatment is performed on the peeling surfaces of the peeling sheets 12a and 12b (in particular, the surface in contact with the peeling layer 11). As the releasing agent used in the peeling treatment, for example, an alkyd type, a silicone type, a fluorine type, an unsaturated polyester type, a polyolefin type, and a wax type releasing agent may be mentioned. One of the peeling sheets 12a and 12b may be a peeling sheet having a large peeling force and the other peeling sheet may be a light peeling type peeling sheet having a small peeling force, .

The thickness of the release sheets 12a, 12b is not particularly limited, but is usually about 20 to 150 mu m.

(3) Production of pressure-sensitive adhesive sheet

In one production example of the adhesive sheet 1, the application liquid of the adhesive composition (P) is applied to the release surface of one release sheet 12a (or 12b) (P) is crosslinked to form a coating layer, and then the release surface of the other release sheet 12b (or 12a) is superimposed on the application layer. When a curing period is required, a curing period is provided, and when the curing period is unnecessary, the applied layer becomes the pressure-sensitive adhesive layer (11). Thus, the pressure-sensitive adhesive sheet (1) is obtained. The conditions of the heat treatment and curing are as described above.

In another production example of the adhesive sheet 1, the application liquid of the adhesive composition (P) is applied to the release surface of one release sheet 12a and heat treatment is performed to crosslink the adhesive composition (P) , A coating layer is formed to obtain a release sheet 12a to which a coating layer is adhered. The application liquid of the adhesive composition (P) is applied to the release surface of the other release sheet (12b) and the adhesive composition (P) is subjected to heat treatment to form a coating layer, Thereby obtaining an attached release sheet 12b. Then, the release sheet 12a to which the application layer is attached and the release sheet 12b to which the application layer is adhered are adhered so that the both application layers are in contact with each other. When the curing period is required, the curing period is provided, and when the curing period is unnecessary, the laminated coating layer becomes the pressure-sensitive adhesive layer (11). Thus, the pressure-sensitive adhesive sheet (1) is obtained. According to this production example, even when the pressure-sensitive adhesive layer 11 is thick, it can be stably produced.

As a method of applying the coating liquid of the adhesive composition (P), for example, a bar coating method, a knife coating method, a roll coating method, a blade coating method, a die coating method, a gravure coating method and the like can be used.

(4) Adhesion

The lower limit of the adhesive force of the pressure-sensitive adhesive sheet 1 according to the present embodiment to soda lime glass is preferably 5 N / 25 mm or more, particularly preferably 8 N / 25 mm or more, and more preferably 10 N / . If the lower limit of the adhesive force of the pressure-sensitive adhesive sheet 1 is higher than the above-mentioned value, the step following property under high temperature and high humidity conditions is excellent. On the other hand, the upper limit value of the adhesive force is not particularly limited, but it is preferably 50 N / 25 mm or less in consideration of the peelability of the release sheets 12a, 12b from the pressure-sensitive adhesive layer 11 at the time of use, Particularly 30 N / 25 mm or less. In consideration of reworkability, it is also preferable that it is 26 N / 25 mm or less. In this case, even when a misalignment has occurred, reuse of the display body constituting member is facilitated.

Here, the cohesive force in this specification refers basically to the adhesive force measured by the 180 degree peeling method in accordance with JIS Z 0237: 2009, but the measurement sample is set to have a width of 25 mm and a length of 100 mm, And pressed at 0.5 MPa for 20 minutes at 50 캜 and then left for 24 hours under the conditions of normal pressure, 23 캜 and 50% RH, and then measured at a peeling rate of 300 mm / min.

[Display]

The display body according to the present embodiment is characterized in that the first display body constructing member, the second display body constructing member, and the first display body constructing member and the second display body constructing member, which have at least a step on the side to be conjugated, And a pressure-sensitive adhesive layer to be bonded together. The pressure-sensitive adhesive layer is composed of the pressure-sensitive adhesive relating to the present embodiment described above. Here, the first display body constituting member and / or the second display body constituting member has an electrode at least on the side to be conjugated (pressure-sensitive adhesive layer side). In a preferred configuration, the second display body constituting member has an electrode at least on the side to which the display body is joined.

Examples of the display body include a liquid crystal (LCD) display, a light emitting diode (LED) display, an organic electroluminescence (organic EL) display, an electronic paper, and the like. The display member may be a member constituting a part of the display member.

It is preferable that the first display body constituting member is a protective panel made of a glass plate, a plastic plate or the like, as well as a laminate including them. The first display body constituting member has a step on the surface of the pressure-sensitive adhesive layer side, and more specifically, it is preferable that the first display body constituting member has a stepped portion by the printed layer. This printing layer is generally formed in a frame-like shape.

The glass plate is not particularly limited and includes, for example, chemically strengthened glass, alkali-free glass, quartz glass, soda lime glass, barium-strontium-containing glass, aluminosilicate glass, lead glass, borosilicate glass, barium borosilicate glass . The thickness of the glass plate is not particularly limited, but is usually 0.1 to 5 mm, preferably 0.2 to 2 mm.

The plastic plate is not particularly limited, and examples thereof include an acrylic plate and a polycarbonate plate. The thickness of the plastic plate is not particularly limited, but is usually 0.2 to 5 mm, preferably 0.4 to 3 mm.

Various functional layers (an electrode layer, a silica layer, a hard coat layer, an antiglare layer or the like) may be formed on one surface or both surfaces of the glass plate or the plastic plate, or optical members may be laminated.

The material constituting the print layer is not particularly limited, and known materials for printing are used. The thickness of the printing layer, that is, the lower limit of the height of the step is preferably 3 mu m or more, more preferably 5 mu m or more, particularly preferably 7 mu m or more, and most preferably 10 mu m or more. When the lower limit value is equal to or larger than the above-described range, it is possible to sufficiently secure concealment such as disabling the electric wiring from being visible from the viewer side. The upper limit value is preferably 50 占 퐉 or less, more preferably 35 占 퐉 or less, particularly preferably 25 占 퐉 or less, further preferably 20 占 퐉 or less. When the upper limit value is less than or equal to the upper limit value, it is possible to prevent deterioration of step difference followability of the pressure-sensitive adhesive layer with respect to the print layer.

The second display body constructing member may include an optical member to be attached to the first display body constructing member, a display module (for example, a liquid crystal (LCD) module, a light emitting diode (LED) module, an organic electroluminescence ) Module, etc.), an optical member as a part of the display body module, or a display body module, and preferably has at least an electrode on the side of the pressure-sensitive adhesive layer.

Examples of the optical member include an electrode film, a transparent conductive film, a film sensor, a metal nanowire film, and a wire grid polarizing film.

As the electrode, for example, a transparent conductive film (including patterned) made of a metal electrode (including a mesh or a grid) made of copper, silver or the like, a tin-doped indium oxide (ITO) . As described above, among the electrodes, a metal electrode mainly composed of a non-oxidized metal, specifically, a metal electrode made of copper or silver is preferable.

Fig. 2 shows an electrostatic capacitive type touch panel 2 as an example of the display body according to the present embodiment. The touch panel 2 includes a display element module 3, a first film sensor 5a laminated thereon with a pressure sensitive adhesive layer 4 interposed therebetween, and a first pressure sensitive adhesive layer 5b laminated thereon with a first pressure sensitive adhesive layer 11 interposed therebetween A second film sensor 5b, and a cover material 6 laminated thereon with a second adhesive layer 11 interposed therebetween. A printing layer 7 is formed on the surface of the cover material 6 on the side of the second pressure sensitive adhesive layer 11 and therefore there is a step due to the presence or absence of the printing layer 7. In the present embodiment, the cover material 6 corresponds to the first display body constituting member and the second film sensor 5b corresponds to the second display body constituting member.

At least the second pressure-sensitive adhesive layer 11 of the touch panel 2 is the pressure-sensitive adhesive layer 11 of the pressure-sensitive adhesive sheet 1 and the first pressure-sensitive adhesive layer 11 and the second pressure- Both of the pressure-sensitive adhesive layer 11 are preferably the pressure-sensitive adhesive layer 11 of the pressure-sensitive adhesive sheet 1. [ When the first pressure-sensitive adhesive layer 11 is not the pressure-sensitive adhesive layer 11 of the pressure-sensitive adhesive sheet 1, the pressure-sensitive adhesive constituting the first pressure-sensitive adhesive layer 11 may be an acrylic pressure-sensitive adhesive, Based pressure-sensitive adhesives, urethane pressure-sensitive adhesives, polyester pressure-sensitive adhesives, and polyvinyl ether pressure-sensitive adhesives. Among them, acrylic pressure-sensitive adhesives are preferable.

The pressure-sensitive adhesive layer (4) may be formed of the pressure-sensitive adhesive layer (11) of the pressure-sensitive adhesive sheet (1) or may be formed of another pressure-sensitive adhesive or pressure-sensitive adhesive sheet. In the latter case, examples of the pressure sensitive adhesive constituting the pressure sensitive adhesive layer 4 include an acrylic pressure sensitive adhesive, a rubber pressure sensitive adhesive, a silicone pressure sensitive adhesive, a urethane pressure sensitive adhesive, a polyester pressure sensitive adhesive and a polyvinyl ether pressure sensitive adhesive. Do.

The first film sensor 5a and the second film sensor 5b in the present embodiment each include a base film 51 and electrodes 52 formed on the base film 51. [ The base film 51 is not particularly limited, and for example, a polyethylene terephthalate film, an acrylic film, a polycarbonate film, or the like is used.

The electrode 52 is made of, for example, a metal electrode made of copper, silver or the like, a patterned transparent conductive film made of tin-doped indium oxide (ITO) or the like.

The electrode 52 of the first film sensor 5a and the electrode 52 of the second film sensor 5b usually constitute a circuit pattern in the X axis direction and the other circuit pattern in the Y axis direction .

The electrode 52 of the second film sensor 5b in this embodiment is located on the upper side of the second film sensor 5b in Fig. On the other hand, the electrode 52 of the first film sensor 5a is located on the upper side of the first film sensor 5a in Fig. 2. However, the electrode 52 is not limited to this, It may be located.

An example of a method of manufacturing the touch panel 2 will be described below.

As the adhesive sheet 1, a first adhesive sheet 1 and a second adhesive sheet 1 are prepared. One of the release sheets 12a is peeled from the first adhesive sheet 1 and the exposed pressure sensitive adhesive layer 11 (first pressure sensitive adhesive layer) is brought into contact with the electrode 52 of the first film sensor 5a, And is then joined to the first film sensor 5a. One of the release sheets 12a is peeled from the second adhesive sheet 1 and the exposed pressure sensitive adhesive layer 11 (second pressure sensitive adhesive layer 11) is peeled off from the electrodes 52 of the second film sensor 5b ) Of the second film sensor 5b.

The other release sheet 12b in the first adhesive sheet is peeled off and the exposed first pressure sensitive adhesive layer 11 is peeled off from the second pressure sensitive adhesive layer 11 in the second film sensor 5b (The exposed surface of the base film 51 of the first film sensor 5b) opposite to the stacked side. Thereby, a laminate in which the release sheet 12b, the second pressure-sensitive adhesive layer 11, the second film sensor 5b, the first pressure-sensitive adhesive layer 11 and the first film sensor 5a are successively laminated is obtained.

Next, the pressure-sensitive adhesive layer 4 formed on the release sheet is stuck to the surface of the laminate on the side of the first film sensor 5a (the exposed surface of the base film 51 of the first film sensor 5a) . Subsequently, the release sheet 12b is peeled off from the laminate and the printed layer 7 side of the cover material 6 is exposed to the exposed second pressure-sensitive adhesive layer 11, The cover material 6 is bonded so as to be in contact therewith. At this time, since the second pressure-sensitive adhesive layer 11 is excellent in the step-following ability at the time of sticking, gaps and lifting in the vicinity of the steps by the print layer 7 are suppressed. By the bonding, the cover material 6, the second pressure sensitive adhesive layer 11, the second film sensor 5b, the first pressure sensitive adhesive layer 11, the first film sensor 5a, the pressure sensitive adhesive layer 4, A structure in which sheets are sequentially laminated is obtained.

Finally, the release sheet is peeled off from the constituent body, and the constituent body is bonded to the display body module 3 so that the exposed pressure-sensitive adhesive layer 4 comes into contact with the display body module 3. Next, Thus, the touch panel 2 shown in Fig. 2 is manufactured.

Even when the touch panel 2 is placed under high temperature and high humidity conditions and a voltage is applied to the electrode 52 in this state, the pressure-sensitive adhesive layer 11 in contact with the electrode 52 is a silane having a mercapto group By containing the component derived from the coupling agent (B), the migration of the electrode (52) is effectively suppressed. As a result, the driving failure of the touch panel 2 caused by disconnection or short-circuiting of the electrode 52 is prevented.

Since the pressure sensitive adhesive layer 11 has excellent step traceability even under high temperature and high humidity conditions, the touch panel 2 is exposed to high temperature and high humidity conditions for a predetermined time (for example, at 85 DEG C and 85% RH for 72 hours) The occurrence of bubbles, lifting, peeling, and the like in the vicinity of the stepped portion by the print layer 7 is effectively suppressed.

The embodiments described above are provided for the purpose of facilitating understanding of the present invention and are not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design modifications and equivalents falling within the technical scope of the present invention.

For example, either one of the release sheets 12a and 12b in the pressure-sensitive adhesive sheet 1 may be omitted.

Example

Hereinafter, the present invention will be described in more detail with reference to Examples and the like, but the scope of the present invention is not limited to these Examples and the like.

[Example 1]

1. Preparation of (meth) acrylic acid ester copolymer

60 parts by mass of 2-ethylhexyl acrylate, 20 parts by mass of methyl methacrylate and 20 parts by mass of 2-hydroxyethyl acrylate were copolymerized to prepare a (meth) acrylic acid ester polymer (A). The molecular weight of the (meth) acrylic acid ester polymer (A) was measured by a method described later, and as a result, the weight average molecular weight (Mw) was 60,000.

2. Preparation of adhesive composition

100 parts by mass of the (meth) acrylic acid ester polymer (A) obtained in the above Step 1 (solid content conversion value: the same), 3-mercaptopropyltrimethoxysilane as the silane coupling agent (B) having a mercapto group, , 0.05 part by mass of a co-condensation product of triethoxysilane (trade name: "X-41-1810", oligomer type, mercapto group equivalent: 450 g / mol, manufactured by Shinetsu Kagaku Kogyo K.K.), and 0.1 part by mass of trimethylolpropane- And 0.23 parts by mass of tolylene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name " Coronate L ") were mixed and thoroughly stirred and diluted with methyl ethyl ketone to obtain a coating solution of a sticky composition having a solid concentration of 38% by mass.

Table 1 shows the respective blend (solid content conversion value) of the adhesive composition when the (meth) acrylic acid ester polymer (A) was changed to 100 parts by mass (solid content conversion value). Details of the abbreviations and the like in Table 1 are as follows.

[(Meth) acrylic acid ester polymer (A)]

2EHA: 2-ethylhexyl acrylate

MMA: methyl methacrylate

HEA: 2-hydroxyethyl acrylate

[Silane coupling agent (B) having a mercapto group]

X-41-1810: A co-condensation product of 3-mercaptopropyltrimethoxysilane and methyltriethoxysilane (trade name: "X-41-1810", manufactured by Shin-Etsu Chemical Co., Ltd., oligomer type, mercapto equivalent: 450 g /mole)

KBM-803: 3-mercaptopropyltrimethoxysilane (trade name: KBM-803, manufactured by Shin-Etsu Chemical Co., Ltd., low molecular weight, mercapto group equivalent: 196.4 g / mol)

[Other silane coupling agent]

KBM-403: 3-glycidoxypropyltrimethoxysilane (trade name " KBM-403 ", manufactured by Shin-Etsu Silicone Co.,

KBE-9007: 3-isocyanate propyltriethoxysilane (trade name: KBE-9007, manufactured by Shin-Etsu Silicone Co., Ltd., low molecular weight)

3. Production of adhesive sheet

The coating solution of the adhesive composition obtained in the above Step 2 was applied to a release treatment surface of a heavy-duty release sheet (trade name: SP-PET382150, thickness: 38 占 퐉) having one side of a polyethylene terephthalate film peeled off with a silicone- Coated with a knife coater, and then heat-treated at 90 占 폚 for 1 minute to form a coating layer (thickness: 25 占 퐉). Likewise, the coating solution of the adhesive composition obtained in the above Step 2 was applied to the release treatment surface of a lightly curled release sheet (trade name "SP-PET382120", manufactured by Lin Tec Co., Ltd.) in which one side of the polyethylene terephthalate film was peeled off with a silicone- Coated with a knife coater, and then heat-treated at 90 DEG C for 1 minute to form a coating layer (thickness: 25 mu m).

Next, the above-obtained heavy-duty releasing sheet with the applied coating layer and the above-obtained lightly curled releasing sheet with the applied layer adhered to each other so as to be in contact with each other. Then, under the condition of 23 캜 and 50% RH, 7 Curing for one day, a pressure-sensitive adhesive sheet comprising a configuration of a heavy-weight releasing sheet / pressure-sensitive adhesive layer (thickness: 50 占 퐉) / light-

[Examples 2 to 10, Comparative Examples 1 to 10]

Same as Example 1 except that the kind and ratio of the silane coupling agent (silane coupling agent (B) having a mercapto group and another silane coupling agent) and the ratio of the crosslinking agent (C) were changed as shown in Table 1 To prepare a pressure-sensitive adhesive sheet. For Comparative Examples 7 to 10, N, N-bis (2-ethylhexyl) - (4 or 5) -methyl-1H-benzotriazole- 1 -methylamine (trade name: IRGMET 39 ") were added to the adhesive composition in the ratios shown in Table 1.

The weight average molecular weight (Mw) described above is a weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC) under the following conditions (GPC measurement).

<Measurement Conditions>

GPC measurement apparatus: HLC-8020 manufactured by Tosoh Corporation

GPC column (passed in the following order): manufactured by Toso Co., Ltd.

TSK guard column HXL-H

TSK gel GMHXL (× 2)

TSK gel G2000HXL

Measurement solvent: tetrahydrofuran

· Measuring temperature: 40 ℃

[Test Example 1] (Measurement of gel fraction)

The pressure-sensitive adhesive sheet obtained in Examples and Comparative Examples was cut into a size of 80 mm x 80 mm, the pressure-sensitive adhesive layer was wrapped with a polyester mesh (mesh size 200), the mass was weighed with a precision balance, By subtracting the mass, the mass of the adhesive alone was calculated. The mass at this time is denoted by M1.

Next, the pressure-sensitive adhesive wrapped in the polyester mesh was immersed in ethyl acetate at room temperature (23 DEG C) for 24 hours. Thereafter, the pressure-sensitive adhesive was taken out and air-dried for 24 hours under an environment of a temperature of 23 ° C and a relative humidity of 50%, and further dried in an oven at 80 ° C for 12 hours. After drying, the mass was weighed with a precision balance and the mass of the mesh alone was subtracted to calculate the mass of the adhesive alone. The mass at this time is M2. The gel fraction (%) is represented by (M2 / M1) x100. The results are shown in Table 2.

[Test Example 2] (Measurement of adhesive force)

The lightly peelable release sheet was peeled off from the pressure-sensitive adhesive sheet obtained in Examples and Comparative Examples, and the exposed pressure-sensitive adhesive layer was laminated on a polyethylene terephthalate (PET) film (product name: "PET A4300" Mu m), and a layered product of a heavy peelable release sheet / pressure-sensitive adhesive layer / PET film was obtained. The obtained laminate was cut into a length of 25 mm and a length of 100 mm, and this was used as a sample.

The peelable release sheet was peeled off from the sample under the environment of 23 占 폚 and 50% RH, and the exposed pressure-sensitive adhesive layer was attached to soda lime glass (manufactured by Nippon Sheet Glass Co., Ltd.) , And pressurized at 50 DEG C for 20 minutes. Thereafter, the adhesive strength (N / m) was measured under the conditions of a temperature of 23 占 폚 and a relative humidity of 50% RH for 24 hours and then using a tensile tester (Tensilon manufactured by Orientec Corporation) 25 mm) was measured. Conditions other than those described herein were measured in accordance with JIS Z 0237: 2009. The results are shown in Table 2.

[Test Example 3] (Evaluation of Migration Prevention Effect)

(1) Production of wiring board

An etching resist pattern was printed on the surface of the copper foil of a copper clad laminate (product of Nikkan Kogyo Co., Ltd., product name &quot; NICAFLEX &quot;) obtained by laminating a copper foil (thickness: 18 μm) and a polyethylene terephthalate film Respectively. Thereafter, unnecessary copper foil was removed by etching to form interdigital electrodes. The line width of each electrode was 300 mu m and the gap between the electrodes was 50 mu m.

(2) Evaluation of the effect of prevention of migration

The lightly peelable release sheet was peeled off from the pressure-sensitive adhesive sheet obtained in Examples and Comparative Examples, and the exposed pressure-sensitive adhesive layer was laminated on a polyethylene terephthalate (PET) film (product name: "PET A4300" Mu m), and a layered product of a heavy peelable release sheet / pressure-sensitive adhesive layer / PET film was obtained. Then, the heavy-duty release sheet was peeled from the laminate, and the exposed pressure-sensitive adhesive layer was stuck on the interdigital electrode, and this was sampled.

The sample was allowed to stand under a moist heat condition of 85 캜 and 85% RH, and a voltage of 5 V was applied between the electrodes in this state, and a migration test was performed. The interdigitated electrodes were observed under an optical microscope (magnification: 10 times) after 8 hours, 24 hours, and 48 hours from the start of the test, and the migration preventing effect was evaluated based on the following evaluation criteria. The results are shown in Table 2.

?: No dissolution of the electrode (positive electrode) and formation of dendrites in the electrode (negative electrode) can be observed at all.

?: Dissolution appears only in the end portion of the electrode (positive electrode), and formation of dendrite in the electrode (negative electrode) can not be seen.

X: Dissolution of the electrode (positive electrode) and formation of dendrite in the electrode (negative electrode) can be seen.

A reference image of the evaluation reference is shown in Fig.

[Test Example 4] (Evaluation of Step Followability)

(a) Preparation of sample for evaluation

POS-911 ink (manufactured by Teikoku Ink Co., Ltd.) was coated on the surface of a glass plate (product name "Corning Glass Eagle XG" manufactured by NSG Precision Co., Ltd., length 90 mm × width 50 mm × thickness 0.5 mm) ) Was screen-printed in a frame-like form (outline: length 90 mm × width 50 mm, width 5 mm) such that the coating thickness was any one of 5 μm, 10 μm and 15 μm. Subsequently, the printed ultraviolet curable ink was cured by irradiating ultraviolet light (80 W / cm 2, metal halide lamp 2, lamp height 15 cm, belt speed 10 to 15 m / min) Height: 5 mu m, 10 mu m, and 15 mu m).

The lightly curled release sheet was peeled off from the pressure-sensitive adhesive sheet obtained in the examples and the comparative example, and the exposed pressure-sensitive adhesive layer was laminated on the easy adhesion layer of a polyethylene terephthalate film (PET A4300, thickness: 100 占 퐉, Respectively. Subsequently, the heavy-duty release sheet was peeled off, and a pressure-sensitive adhesive layer was exposed. Then, the laminate was laminated to a glass plate on which each step was formed by using a laminator (manufactured by Fuji Plasma, product name "LPD3214") so that the pressure-sensitive adhesive layer covers the entire printed surface on the frame image.

(b) Evaluation of sample for evaluation

The obtained evaluation sample was subjected to autoclave treatment at 50 캜 under 0.5 MPa for 30 minutes and then left at normal pressure, 23 캜, and 50% RH for 24 hours. Then, it was stored for 72 hours under the conditions of 85 DEG C and 85% RH. Thereafter, the pressure-sensitive adhesive layer (in particular, the vicinity of the step difference due to the print layer) was visually observed, and the stepwise followability was evaluated according to the following criteria. The results are shown in Table 2.

◎: There was no bubble or lifting.

○: Less than 10 bubbles were observed near the step.

X: There was air bubbles and / or lifting.

[Test Example 5] (Evaluation of anti-wet heat whitening property)

The pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet obtained in Examples or Comparative Examples was placed between two sheets of non-alkali glass having a thickness of 1.1 mm, and the layered product was used as a sample. The obtained sample was stored for 120 hours under the conditions of 85 캜 and 85% RH. Thereafter, the temperature was returned to normal temperature and normal humidity at 23 占 폚 and 50% RH, and the presence or absence of whitening was visually confirmed by the following criteria, and the haze value of the pressure-sensitive adhesive layer was evaluated. The haze value was measured according to JIS K 7136: 2000 using a haze meter (product name: "NDH2000", manufactured by Nippon Denshoku Industries Co., Ltd.) within 30 minutes after returning the sample to normal temperature and normal humidity. The results are shown in Table 2.

○: Even if it was returned to normal temperature and humidity, whitening was not confirmed. Or partially whitened, but was lost within 30 minutes.

X: Overall whitened. Or partially whitened, it did not return to its original state even when stored under ordinary temperature and humidity.

As can be seen from Table 2, the pressure-sensitive adhesive sheet obtained in the Examples was excellent in migration prevention effect, step-following property and anti-wet heat-releasing property.

Industrial availability

The adhesive composition, the pressure-sensitive adhesive and the pressure-sensitive adhesive sheet according to the present invention can be suitably used, for example, in a capacitive touch panel using a copper electrode or a silver electrode. Further, the display body according to the present invention is preferable as a capacitive touch panel using, for example, a copper electrode or a silver electrode.

(1): adhesive sheet
(11): pressure-sensitive adhesive layer
(12a), (12b): peeling sheet
(2): Touch panel
(3): Display body module
(4): pressure-sensitive adhesive layer
(5a): the first film sensor
(5b): the second film sensor
(51): substrate film
(52): electrode
(6): Cover material
(7): Printed layer

Claims (10)

A pressure-sensitive adhesive composition for forming a pressure-sensitive adhesive for bonding a first display body constituting member and a second display body constituting member,
Wherein the first display body constituting member and / or the second display body constituting member has an electrode at least on a side to be conjugated,
The adhesive composition according to claim 1,
(Meth) acrylic acid ester polymer (A)
And a silane coupling agent (B) having a mercapto group. The method according to claim 1,
Wherein the mercapto group-containing silane coupling agent (B) is a mercapto group-containing oligomer type silane coupling agent. 3. The method according to claim 1 or 2,
Wherein the mercapto group equivalent of the organosilicon compound constituting the mercapto group-having silane coupling agent (B) is 100 g / mol or more and 1000 g / mol or less. 4. The method according to any one of claims 1 to 3,
The content of the mercapto group-containing silane coupling agent (B) in the viscous composition is 0.01 part by mass or more and 5 parts by mass or less based on 100 parts by mass of the (meth) acrylic acid ester polymer (A) Lt; / RTI &gt; 5. The method according to any one of claims 1 to 4,
Wherein the (meth) acrylic acid ester polymer (A) contains 3 mass% or more and 35 mass% or less of a hydroxyl group-containing monomer as a monomer unit constituting the polymer. 6. The method according to any one of claims 1 to 5,
Wherein the viscous composition further comprises a cross-linking agent (C). A pressure-sensitive adhesive comprising the pressure-sensitive adhesive composition according to any one of claims 1 to 6 crosslinked. A pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer comprising the pressure-sensitive adhesive according to claim 7. 9. The method of claim 8,
The pressure-sensitive adhesive sheet is provided with two release sheets,
Wherein the pressure-sensitive adhesive layer is sandwiched between the peeling sheet so as to come into contact with the peeling surface of the two peeling sheets. A first display body constituting member having at least a step on a surface to be conjugated,
A second display body constituting member,
And a pressure-sensitive adhesive layer for bonding the first display body constituting member and the second display body constituting member to each other,
Wherein the first display body constituting member and / or the second display body constituting member has an electrode at least on the side to which the display body is to be bonded,
Wherein the pressure-sensitive adhesive layer is the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet according to claim 8 or 9.

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