TW201702342A - Adhesive composition, adhesive, adhesive sheet and display element - Google Patents

Abstract

An adhesive composition which forms an adhesive for bonding a first display element constituting member that has a level difference at least in a surface to be bonded and a second display element constituting member with each other. The first display element constituting member and/or the second display element constituting member has an electrode at least on a surface to be bonded. The adhesive composition contains (A) a (meth)acrylic acid ester polymer and (B) a silane coupling agent having a mercapto group. An adhesive obtained from this adhesive composition is capable of effectively preventing/suppressing migration at the electrode.

Description

Adhesive composition, adhesive, adhesive sheet and display body

The present invention relates to an adhesive composition, an adhesive, an adhesive sheet which can be used for a display body such as a touch panel, and a display body using the same.

In recent years, in various mobile electronic devices such as smart phones and tablet computers, a touch panel has been frequently used as a display. As a method of the touch panel, there are a resistive film method, an electrostatic capacitance method, and the like, and in the mobile electronic device as described above, a capacitance type is mainly employed.

Recently, as the electrode material for such a touch panel has been demanded, the mesh metal electrode, for example, a copper electrode or a silver electrode, has been studied. However, when a conventional 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 to cause disconnection, or in the negative electrode, a branch crystal is formed by precipitation of the positive electrode component to cause a short circuit.

This migration is particularly likely to occur when a voltage is applied to the electrodes under high temperature and high humidity. If this kind of migration occurs, the touch panel will not drive properly. In particular, the miniaturization and narrow pitch of electrodes have been progressing recently, and disconnection and short-circuiting of electrodes due to migration are likely to occur.

However, Patent Document 1 discloses that a benzotriazole compound is contained. An adhesive composition for a touch panel as a rust preventive.

[Previous Technical Literature]

[Patent Literature]

Patent Document 1: Japanese Laid-Open Patent Publication No. 2014-177611

However, the benzotriazole compound as a rust preventive agent cannot sufficiently prevent and inhibit migration even if it has an anticorrosive effect of metal wiring.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an adhesive composition, an adhesive, an adhesive sheet, and a display body which can effectively prevent and suppress migration.

In order to achieve the above object, the present invention provides an adhesive composition which is formed by laminating a first display member constituting member having a step on at least a side of a bonding surface and a second display member constituting member. In the adhesive, the first display member constituting member and/or the second display member constituting member have electrodes on at least the surface on the side where they are bonded, and the adhesive composition contains a (meth) acrylate polymer ( A) A decane coupling agent (B) having a mercapto group (Invention 1).

The adhesive obtained by the adhesive composition of the above invention (Invention 1), particularly by the action of the decane coupling agent (B) having a mercapto group, can effectively prevent and suppress the adhesion of the first display body to be contacted The migration in the electrodes of the constituent members and/or the second display constituent members.

In the above invention (Invention 1), the aforementioned decane coupling having a mercapto group The agent (B) is preferably a thiol-containing oligomer-type decane coupling agent (Invention 2).

In the above inventions (Inventions 1 and 2), the sulfhydryl equivalent of the organic ruthenium compound constituting the decane coupling agent (B) having a mercapto group is preferably 100 g/mol or more and 1000 g/mole or less (Invention 3).

In the above invention (Inventions 1 to 3), the content of the decane coupling agent (B) having a mercapto group in the adhesive composition is 0.01 by mass based on 100 parts by mass of the (meth)acrylate polymer (A). More than 5 parts by weight or less is preferred (Invention 4).

In the above invention (Inventions 1 to 4), it is preferred that the (meth) acrylate polymer (A) contains 3% by mass or more and 35% by mass or less of a hydroxyl group-containing monomer as a monomer unit constituting the polymer. (Invention 5).

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

Secondly, the present invention provides an adhesive characterized in that the adhesive composition (Inventions 1 to 6) is crosslinked by an adhesive (Invention 7).

Thirdly, the present invention provides an adhesive sheet having an adhesive layer composed of the above-mentioned adhesive (Invention 7) (Invention 8).

In the above invention (Invention 8), the pressure-sensitive adhesive sheet includes two release sheets, and the pressure-sensitive adhesive layer is preferably sandwiched between the release sheets in contact with the release surfaces of the two release sheets (Invention 9).

According to a fourth aspect of the invention, there is provided a display body comprising: a first display body constituting member having a step at least on a side of the bonding; a second display constituting member; and the first display constituting member and the first 2, showing an adhesive layer in which the body constituent members are bonded to each other, the display body being characterized by the first display The body constituting member and/or the second display constituting member have electrodes on at least the surface on the side where they are bonded, and the adhesive layer is an adhesive layer of the above-mentioned adhesive sheet (Inventions 8 and 9) (Invention 10).

According to the adhesive composition, the adhesive, the adhesive sheet and the display body of the present invention, migration can be effectively prevented and suppressed.

1‧‧‧Adhesive film

11‧‧‧Adhesive layer

12a, 12b‧‧‧ peeling film

2‧‧‧Touch panel

3‧‧‧Display body module

4‧‧‧Adhesive layer

5a‧‧‧1st film sensor

5b‧‧‧2nd film sensor

51‧‧‧Substrate film

52‧‧‧Electrode

6‧‧‧ Covering materials

7‧‧‧Printing layer

Fig. 1 is a cross-sectional view showing an adhesive sheet according to an embodiment of the present invention.

Fig. 2 is a cross-sectional view showing a configuration example of a touch panel.

Fig. 3 is a reference image of the evaluation criteria in the evaluation of the migration prevention effect of Test Example 3.

Hereinafter, embodiments of the present invention will be described.

[adhesive composition]

The adhesive composition of the present embodiment (hereinafter sometimes referred to as "adhesive composition P") is a first display member constituting member and a second display which are formed to have a step for bonding at least the surface on the bonding side. An adhesive composition of an adhesive for a body constituting member (the first display constituting member and/or the second display constituting member having at least a surface on the bonding side) containing a (meth) acrylate polymer (A) And a decane coupling agent (B) having a mercapto group, and further containing a crosslinking agent (C) is preferred. In the present specification, (meth) acrylate means both acrylate and methacrylate. Other similar terms are also the same. Also, "polymer" is considered to be a concept that also includes "copolymer". In addition, regarding the display body and the display body constituent member This will be described later.

The adhesive composition P of the present embodiment contains a decane coupling agent (B) having a mercapto group. When the adhesive obtained from the adhesive composition P is in contact with the electrode, the electrode can be prevented from being dissolved and suppressed in the negative electrode. Formation of dendrite crystals can be prevented and suppressed. That is, migration in the electrode can be effectively prevented and suppressed (this effect is sometimes referred to as "migration prevention effect"). Thereby, even when the above-mentioned adhesive is brought into contact with, for example, a finely divided and narrow-pitched electrode, disconnection and short-circuiting of the electrode can be prevented. In particular, when the electrode is an electrode of a touch panel, it is possible to prevent driving failure of the touch panel caused by disconnection and short circuit of the electrode.

In addition, examples of the electrode include a metal electrode (including a mesh or a grid) made of copper or silver, and a transparent conductive film made of tin-doped indium oxide (ITO) or the like (including a pattern). Wait. Among the above electrodes, a metal electrode mainly composed of an unoxidized metal, specifically a metal electrode composed of copper or silver is preferable. The ionization tendency of the unoxidized metal is higher than that of the metal oxide such as ITO. However, the adhesive obtained by the adhesive composition P of the present embodiment can effectively prevent the electrode from being broken even in this case. Line and short circuit.

Further, the adhesive layer composed of the adhesive obtained from the adhesive composition P containing the decane coupling agent (B) having a mercapto group is derived from the sulfhydryl group at the interface with the constituent member constituting the adherend. The component of the decane coupling agent (B) has high adhesion to the display constituent member and is excellent in step followability. Specifically, even when the adhesive layer is attached to the display body constituent member having a step and exposed to high temperature and high humidity conditions for a predetermined period of time (for example, at 85 ° C, 85% RH, 72 hours) Can also suppress Air bubbles, floating, peeling, and the like are generated in the vicinity of the step (excellent step followability under high temperature and high humidity conditions). Thereby, the reflection loss of the light generated in the vicinity of the step is suppressed, and the image quality of the display body can be favorably maintained.

(1) (meth) acrylate polymer (A)

The (meth) acrylate polymer (A) can exhibit a good adhesion by using an alkyl (meth) acrylate having an alkyl group and having 1 to 20 carbon atoms as a monomer unit constituting the polymer. . From such a viewpoint, the (meth) acrylate polymer (A) contains an alkyl (meth) acrylate having an alkyl group having a lower limit of 50% by mass or more and a carbon number of 1 to 20 as a constituent of the polymerization. The monomer unit is preferably contained in an amount of 60% by mass or more, and more preferably 70% by mass or more. When the (meth)acrylic acid alkyl ester is contained in an amount of 50% by mass or more, the (meth)acrylate polymer (A) can exhibit better adhesion. Further, the (meth) acrylate polymer (A) contains the above (meth)acrylic acid alkyl ester having an upper limit of 97% by mass or less, preferably as a monomer unit constituting the polymer, and contains 90% by mass. The following is particularly preferable, and it is further preferable to contain 85% by mass or less. A preferred amount of the other monomer component can be introduced into the (meth) acrylate polymer (A) by containing 97% by mass or less of the above alkyl (meth) acrylate.

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, and propyl (meth)acrylate. N-butyl acrylate, n-amyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, (meth)acrylic acid N-decyl ester, n-dodecyl (meth)acrylate, tetradecyl (meth)acrylate, (methyl) Cetyl acrylate, octadecyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, adamantyl (meth) acrylate, etc. From the viewpoint of further improving the adhesion, a (meth) acrylate having an alkyl group having 4 to 8 carbon atoms is preferred. These may be used singly or in combination of two or more. Further, the alkyl group in the alkyl (meth)acrylate having 1 to 20 carbon atoms in the alkyl group means a linear, branched or cyclic alkyl group.

Further, as the alkyl (meth) acrylate having an alkyl group having 1 to 20 carbon atoms, a glass transition temperature (Tg) which is a homopolymer is used in combination with a hard one (more preferably 70 ° C or higher). A soft monomer having a glass transition temperature (Tg) of 0 ° C or less as a homopolymer is also preferred. This is because the soft monomer maintains adhesion and flexibility, and the cohesive force is increased by the hard monomer, whereby the step difference in the display panel (touch panel) can be further improved.

The mass ratio of the above hard monomer to the soft monomer is preferably 5:95 to 40:60, and particularly 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), and acrylic acid. Alkyl ester (Tg 115 ° C), adamantyl methacrylate (Tg 141 ° C), and the like. These may be used singly 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 preventing adverse effects on other properties such as adhesion and transparency and further exerting the performance of the hard monomer. . Methyl acrylate and methyl methacrylate are more preferred if adhesion is also considered, and methyl methacrylate is particularly preferred.

As the soft monomer, an alkyl acrylate having a linear or branched alkyl group having 2 to 12 carbon atoms is preferable. For example, 2-ethylhexyl acrylate (Tg-70 ° C), n-butyl acrylate (Tg-54 ° C), and the like are preferable. These may be used singly or in combination of two or more.

The (meth) acrylate polymer (A) preferably contains a reactive functional group-containing monomer as a monomer unit constituting the polymer. The reactive functional group derived from the reactive functional group-containing monomer is reacted with a crosslinking agent (C) described later to form a crosslinked structure (three-dimensional network structure), whereby an adhesive having a desired cohesive force can be obtained. .

The reactive functional group monomer contained as the monomer unit constituting the polymer in the (meth) acrylate polymer (A) is preferably a monomer having a hydroxyl group in the molecule (hydroxy group-containing) Monomer), a monomer having a carboxyl group in a molecule (a carboxyl group-containing monomer), a monomer having an amine group in a molecule (an amine group-containing monomer), and the like. Among these, a hydroxyl group-containing monomer which is excellent in reactivity with a crosslinking agent (C) and wet heat whitening resistance and which has little influence on the electrode is particularly preferable.

Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 2-(meth)acrylate. A hydroxyalkyl (meth)acrylate such as hydroxybutyl ester, 3-hydroxybutyl (meth)acrylate or 4-hydroxybutyl (meth)acrylate. Among them, from the viewpoint of the reactivity of the hydroxyl group in the obtained (meth) acrylate polymer (A) with the crosslinking agent (C) and the copolymerizability with other monomers, 2-hydroxyl (meth) acrylate Ethyl ester or 4-hydroxybutyl (meth)acrylate is preferred. These may be used alone or in combination of two or more.

Examples of the carboxyl group-containing monomer include acrylic acid and methyl propyl acrylate. An ethylenically unsaturated carboxylic acid such as an acid, a crotonic acid, a maleic acid, an itaconic acid or a citraconic acid. Among them, acrylic acid is preferred from the viewpoints of the reactivity of the carboxyl group in the obtained (meth)acrylate polymer (A) with the crosslinking agent (C) and the copolymerizability with other monomers. These may be used alone or in combination of two or more.

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

The (meth) acrylate polymer (A) contains a hydroxyl group-containing monomer having a lower limit of 3% by mass or more, preferably as a monomer unit constituting the polymer, more preferably 10% by mass or more, and particularly preferably 15% by mass. More than % is further preferred. In addition, the (meth) acrylate polymer (A) contains a hydroxyl group-containing monomer having an upper limit of 35% by mass or less, and is preferably a monomer unit constituting the polymer, and particularly preferably contains 30% by mass or less. 25 mass% or less is further preferable. When the (meth) acrylate polymer (A) contains a hydroxyl group-containing monomer as a monomer unit in the above amount, a predetermined amount of a hydroxyl group remains in the obtained adhesive. a hydroxy-based hydrophilic group, if the hydrophilic group is present in the adhesive, even if the adhesive is placed under high temperature and high humidity conditions, and immersed in the adhesive under the high temperature and high humidity conditions The compatibility is also good, and as a result, it is possible to suppress whitening (excellent resistance to moist heat whitening) of the adhesive when the normal temperature and normal humidity are restored.

The degree of whitening inhibition is preferably 1.0% or less, more preferably 0.9% or less, and 0.8% or less, in the case where the temperature of the adhesive layer after normal temperature and high humidity is applied after the application of the high temperature and high humidity conditions (the value measured according to JIS K7136:2000) is preferably 1.0% or less. The following is further preferred. Further, the adhesive layer preferably has a haze value as described above in a normal state. If the haze value is 1.0% or less, the transparency is very high and it becomes suitable. For optical applications.

However, if the hydrophilic group is present in the adhesive as described above, the adhesive easily absorbs water, and migration is likely to occur in the electrode in contact with the adhesive. However, the adhesive composition P of the present embodiment can effectively prevent and suppress migration in the electrode to be contacted by containing the decane coupling agent (B) having a mercapto group.

The (meth) acrylate polymer (A) does not contain a carboxyl group-containing monomer as a monomer unit constituting the polymer, but it is allowed to contain a predetermined amount. This is because the carboxyl group-based acid component is generally worried about the migration of the target member. However, the adhesive of the present embodiment is obtained from the adhesive composition P containing a decane coupling agent (B) having a mercapto group, whereby even a carboxyl group is present. It can also exert the migration prevention effect. Specifically, in the (meth) acrylate polymer (A), the carboxyl group-containing monomer is contained in an amount of 5% by mass or less as the monomer unit, and it is preferable to contain the carboxyl group-containing monomer in an amount of 2% by mass or less. .

The (meth) acrylate polymer (A) may contain other monomers as a monomer unit constituting the polymer, as needed. As the other monomer, in order not to hinder the action of the reactive functional group-containing monomer, a monomer having no reactive functional group is preferable. Examples of such other monomers include (meth)acrylic acid alkoxyalkyl esters such as methoxyethyl (meth)acrylate and ethoxyethyl (meth)acrylate, and (meth)acrylic acid. Non-crosslinkable tertiary amine group such as N,N-dimethylaminoethyl ester, N,N-dimethylaminopropyl (meth)acrylate, or (meth)propenylmorpholine (Meth) acrylate, (meth) acrylamide, dimethyl methacrylate, vinyl acetate, styrene, and the like. These may be used singly or in combination of two or more.

The polymerization form of the (meth) acrylate polymer (A) may be a random copolymer or a block copolymer.

The lower limit of the weight average molecular weight of the (meth) acrylate polymer (A) is preferably 200,000 or more, more preferably 300,000 or more, and still more preferably 400,000 or more. When the lower limit of the weight average molecular weight of the (meth) acrylate polymer (A) is at least the above, the adhesive is excellent in the step-following property under high-temperature and high-humidity conditions. Further, the weight average molecular weight in the present specification is a value in terms of standard polystyrene measured by a gel permeation chromatography (GPC) method.

Further, the upper limit of the weight average molecular weight of the (meth) acrylate polymer (A) is preferably 1,000,000 or less, more preferably 900,000 or less, and still more preferably 700,000 or less. When the upper limit of the weight average molecular weight of the (meth) acrylate polymer (A) is the above or less, the adhesive is excellent in the step-followability at the time of attachment.

Further, in the adhesive composition P, the (meth) acrylate polymer (A) may be used alone or in combination of two or more.

(2) a decane coupling agent having a mercapto group (B)

The decane coupling agent (B) having a mercapto group is composed of an organic ruthenium compound having at least one mercapto group in the molecule and having at least one alkoxyalkyl group. In consideration of the use of the obtained adhesive, it is preferred that the decyl coupling agent (B) having a mercapto group is light transmissive, for example, substantially transparent.

Specific examples of the decane coupling agent (B) having a mercapto group include 3-mercaptopropyltrimethoxydecane, 3-mercaptopropyltriethoxydecane, and 3-mercaptopropyldimethoxymethylnonane. a low molecular weight decane coupling agent containing a mercapto group; 3-mercaptopropyltrimethoxydecane, 3-mercaptopropyltriethoxydecane, 3-mercaptopropyldimethoxy a cocondensate of an alkyl group-containing decane compound such as a methyl decane-containing decane compound with methyl triethoxy decane, ethyl triethoxy decane, methyl trimethoxy decane or ethyl trimethoxy decane An oxime-containing oligomer-type decane coupling agent or the like. Among them, a mercapto group-containing oligomer-type decane coupling agent which is more excellent in migration prevention effect and workability is preferable, and a co-condensation product of a mercapto group-containing decane compound and an alkyl group-containing decane compound is particularly preferable. A cocondensate of a trimethoxy decane and methyl triethoxy decane is further preferred. These may be used alone or in combination of two or more.

The lower limit of the thiol equivalent of the organic hydrazine compound constituting the decane coupling agent (B) having a mercapto group is preferably 100 g/mole or more, more preferably 120 g/mole or more, and still more preferably 150 g/mole or more. By setting the lower limit as described above, the difference in polarity from the (meth) acrylate polymer (A) is within an appropriate range, and the dispersibility of the decane coupling agent (B) in the adhesive can be used. Better.

The upper limit of the thiol equivalent of the organic hydrazine compound constituting the decane coupling agent (B) having a mercapto group is preferably 1000 g/mole or less, more preferably 800 g/mole or less, and further preferably 500 g/mole or less. By setting the upper limit as described above, deterioration of optical characteristics due to phase separation from the (meth) acrylate polymer (A) can be prevented.

The content of the decane coupling agent (B) having a mercapto group in the adhesive composition P is preferably 0.01 parts by mass or less, and preferably 0.05 parts by mass based on 100 parts by mass of the (meth) acrylate polymer (A). More preferably, it is more preferably 0.1 part by mass or more. Further, the upper limit is preferably 5 parts by mass or less, more preferably 1.5 parts by mass or less, and even more preferably 1.0 part by mass or less. good. When the content of the decane coupling agent (B) having a mercapto group is in the above range, the migration preventing effect is further excellent.

Further, the lower limit of the molar number (the amount of sulfhydryl groups) of the fluorenyl group in the decane coupling agent (B) per 100 g of the (meth) acrylate polymer (A) is preferably 0.01 mmol or more, and particularly preferably 0.1 mmol or more. Preferably, 0.2 mmol or more is further preferred. Further, the upper limit of the molar number is preferably 30 mmol or less, more preferably 5 mmol or less, and still more preferably 1.5 mmol or less. When the molar ratio of the fluorenyl group of the decane coupling agent (B) to the (meth) acrylate polymer (A) is in the above range, it is possible to further improve the migration prevention effect.

(3) Crosslinking agent (C)

It is preferred that the adhesive composition P contains a crosslinking agent (C). The adhesive composition P crosslinks the (meth) acrylate polymer (A) by the crosslinking agent (C) to form a three-dimensional network structure, thereby improving the cohesive force of the obtained adhesive, thereby further increasing the high temperature. The difference in follow-up under high humidity conditions.

The crosslinking agent (C) may be reacted with a reactive group of the (meth) acrylate polymer (A), and examples thereof include an isocyanate crosslinking agent and an epoxy crosslinking agent. , an amine crosslinking agent, a melamine crosslinking agent, an aziridine crosslinking agent, a hydrazine crosslinking agent, an aldehyde crosslinking agent, an oxazoline crosslinking agent, a metal alkoxide crosslinking agent, A metal chelate crosslinking agent, a metal salt crosslinking agent, an ammonium salt crosslinking agent, and the like. When the (meth) acrylate polymer (A) contains a hydroxyl group-containing monomer as a monomer unit constituting the polymer, an isocyanate crosslinking agent excellent in reactivity with the hydroxy group is preferably used. Further, the crosslinking agent (C) may be used alone or in combination of two or more.

The isocyanate crosslinking agent contains at least a polyisocyanate compound By. Examples of the polyisocyanate compound include aromatic polyisocyanates such as toluene diisocyanate, diphenylmethane diisocyanate and benzodimethyl diisocyanate; aliphatic polyisocyanates such as hexamethylene diisocyanate; and isophorone diisocyanate. And alicyclic polyisocyanates such as hydrogenated diphenylmethane diisocyanate and the like, and the biuret, isocyanurate, and ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, and hydrazine Sesame oil or the like is an adduct of a reactant with a low molecular weight active hydrogen compound. Among them, trimethylolpropane-modified aromatic polyisocyanate is preferred from the viewpoint of reactivity with a hydroxyl group, and trimethylolpropane-modified toluene diisocyanate is particularly preferred.

The content of the crosslinking agent (C) in the adhesive composition P is preferably 0.001 parts by mass or more based on 100 parts by mass of the (meth) acrylate polymer (A), and more preferably 0.01 parts by mass or more. Preferably, 0.02 parts by mass or more is further preferred. Further, the upper limit is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and still more 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 adhesive is preferable, and the step followability of the adhesive is further improved, in particular, the step followability under high temperature and high humidity conditions is further improved.

(4) Various additives

The adhesive composition P may be added with various additives commonly used in acrylic adhesives, such as an antistatic agent, a tackifier, an antioxidant, an ultraviolet absorber, a light stabilizer, a softener, a filler, and a refractive index. Adjusting agent, etc. Further, in addition to the above-described decane coupling agent (B) having a mercapto group, another decane coupling agent is additionally added. However, the rust preventive agent, particularly the benzotriazole-based rust preventive agent, has an effect of inhibiting the crosslinking of the adhesive composition P, and therefore it is preferably not added.

In addition, the adhesive composition P is a mixture of various components remaining in the original state or the reaction state in the adhesive layer, and the component removed in the drying process or the like, for example, a polymerization solvent and a diluent solvent to be described later are not contained in the adhesive. In the composition P.

(5) Manufacture of adhesive composition

The adhesive composition P can be produced by mixing the (meth) acrylate polymer (A) and the obtained (meth) acrylate polymer (A), a decane coupling agent (B) having a mercapto group, and It is required to be produced by adding a crosslinking agent (C) and an additive.

The (meth) acrylate polymer (A) can be produced by polymerizing a mixture of monomer units constituting the polymer by a usual radical polymerization method. The polymerization of the (meth) acrylate polymer (A) can be carried out by a solution polymerization method or the like using a polymerization initiator as needed. Examples of the polymerization solvent include ethyl acetate, n-butyl acetate, isobutyl acetate, toluene, acetone, hexane, and methyl ethyl ketone, and two or more kinds thereof may be used in combination.

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 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), and 1,1'-azobis (cyclohexane). Alkane 1-carbonitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethyl-4-methoxypentyl) Nitrile), dimethyl 2,2'-azobis(2-methylpropionate), 4,4'-azobis(4-cyanovaleric acid), 2,2'-azobis 2-hydroxymethylpropionitrile), 2,2'-azobis[2-(2-imidazolin-2-yl)propane, and the like.

Examples of the organic peroxide include benzammonium peroxide, t-butyl peroxybenzoate, cumene hydroperoxide, and diisocarbonic acid disulfide. Propyl ester, di-n-propyl peroxydicarbonate, bis(2-ethoxyethyl)peroxydicarbonate, t-butyl peroxy neodecanoate, t-butyl peroxypivalate, (3,5 , 5-trimethylhexyl) peroxide, dipropylene peroxide, diethyl hydrazine peroxide, and the like.

Further, in the above polymerization process, the weight average molecular weight of the obtained polymer can be adjusted by blending a chain transfer agent such as 2-mercaptoethanol.

When the (meth) acrylate polymer (A) is obtained, a decane coupling agent (B) having a mercapto group and a crosslinking agent (C) as needed are added to the solution of the (meth) acrylate polymer (A). The additive and the diluent solvent are mixed well, whereby an adhesive composition P (coating solution) diluted with a solvent is obtained.

Examples of the diluent solvent include an aliphatic hydrocarbon such as hexane, heptane or cyclohexane, an aromatic hydrocarbon such as toluene or xylene, a halogenated hydrocarbon such as dichloromethane or dichloroethane, methanol, ethanol or propanol. Alcohols such as butanol and 1-methoxy-2-propanol, ketones such as acetone, methyl ethyl ketone, 2-pentanone, isophorone, cyclohexanone, ethyl acetate, butyl acetate, etc. A cellosolve such as a solvent is a solvent or the like.

The concentration and viscosity of the coating solution thus prepared are not particularly limited as long as they are within the range of the coatable layer, and may be appropriately selected depending on the situation. For example, the concentration of the adhesive composition P diluted is 10 to 40% by mass. Further, when the coating solution is obtained, the addition of a diluent solvent or the like is not a requirement, and the diluent solvent may not be added as long as the adhesive composition P is a coatable viscosity or the like. At this time, the adhesive composition P is a coating solution in which the polymerization solvent of the (meth) acrylate polymer (A) is directly used as a diluent solvent.

[adhesive]

The adhesive of the present embodiment is obtained by crosslinking the above-mentioned adhesive composition P. Crosslinking of the adhesive composition P can be carried out by heat treatment. In addition, it can also The drying treatment when volatilizing the diluted solvent or the like of the applied adhesive composition P also serves as the heat treatment.

When the heat treatment is performed, the heating temperature is preferably 50 to 150 ° C, and particularly preferably 70 to 120 ° C. Further, the heating time is preferably 30 seconds to 10 minutes, and particularly preferably 50 seconds to 2 minutes. After the heat treatment, a aging period of about 1 to 2 weeks at normal temperature (for example, 23 ° C, 50% RH) may be provided as needed. When the aging period is required, the adhesive layer is formed after the aging period, and when the aging period is not required, the adhesive layer is formed after the heat treatment is completed.

The lower limit of the gel fraction of the adhesive of the present embodiment is preferably 30% or more, more preferably 40% or more, and still more preferably 50% or more. When the lower limit of the gel fraction of the adhesive is at least the above, the cohesive force of the adhesive becomes high, and the step-followability in the high-temperature and high-humidity conditions is excellent. Further, the upper limit of the gel fraction is preferably 90% or less, more preferably 85% or less, and still more preferably 80% or less. When the upper limit of the gel fraction of the adhesive is not more than the above, the adhesive does not become too hard, and the step-following property at the time of attachment is excellent. The method for measuring the gel fraction of the adhesive is as shown in the test examples described later.

[adhesive sheet]

As shown in Fig. 1, the adhesive sheet 1 of the present embodiment is composed of two release sheets 12a and 12b and two release sheets which are in contact with the peeling surfaces of the two release sheets 12a and 12b. Adhesive layer 11 held by 12a, 12b. However, in the adhesive sheet 1, the release sheets 12a and 12b are not necessarily required to be formed, and are peeled off or removed when the adhesive sheet 1 is used. In addition, the peeling surface of the peeling sheet in this specification is the surface which has the peeling property in the peeling sheet, and is the surface which carried out the peeling process, and the surface which shows the peeling-

(1) Adhesive layer

The adhesive layer 11 is composed of the aforementioned adhesive. The lower limit of the thickness of the adhesive layer 11 (the value measured according to JIS K7130) is preferably 10 μm or more, more preferably 25 μm or more, and still more preferably 50 μm or more. When the lower limit of the thickness of the adhesive layer 11 is at least the above, excellent adhesion can be sufficiently exhibited. Further, the upper limit of the thickness of the adhesive layer 11 is preferably 300 μm or less, more preferably 250 μm or less, and further preferably 100 μm or less. When the upper limit of the thickness of the pressure-sensitive adhesive layer 11 is the above or lower, the workability is good. Further, the adhesive layer 11 may be formed in a single layer or may be formed by laminating a plurality of layers.

(2) peeling sheet

The release sheets 12a and 12b are not particularly limited, and a known plastic film can be used. For example, a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, a polymethylpentene film, a polyvinyl chloride film, a vinyl chloride copolymer film, or a polyethylene terephthalate film can be used. , polyethylene naphthalate film, polybutylene terephthalate film, polyurethane film, ethylene vinyl acetate film, ionomer resin film, ethylene ‧ (meth) acrylate copolymer film, vinyl ‧ (A Acrylate copolymer film, polystyrene film, polycarbonate film, polyimide film, fluororesin film, and the like. Further, these crosslinked films can also be used. Alternatively, these laminated films may be used.

It is preferable that the release surface of the release sheets 12a and 12b (especially the surface in contact with the adhesive layer 11) is subjected to a release treatment. Examples of the release agent used in the release treatment include an alkyd type, an anthrone type, a fluorine type, an unsaturated polyester type, a polyolefin type, and a wax type release agent. Further, in the release sheets 12a and 12b, one release sheet is a heavy release type release sheet having a large peeling force, and the other peeling sheet is peeled off. It is preferable that the release sheet is a light release type release sheet having a small peeling force.

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

(3) Manufacture of adhesive sheets

As a production example of the pressure-sensitive adhesive sheet 1, the coating liquid of the above-mentioned adhesive composition P is applied to the release surface of one release sheet 12a (or 12b), and heat treatment is performed to crosslink the adhesive composition P to form a coating. After the layer, the peeling surface of the other release sheet 12b (or 12a) is superposed on the coating layer. When the aging period is required, the coating layer becomes the adhesive layer 11 by the aging period, and when the aging period is not required, the coating layer directly becomes the adhesive layer 11. Thereby, the above-mentioned adhesive sheet 1 is obtained. The heat treatment and ripening conditions are as described above.

In another example of the production of the adhesive sheet 1, the coating liquid of the adhesive composition P is applied onto the peeling surface of one of the release sheets 12a, and heat treatment is performed to crosslink the adhesive composition P to form a coating layer. A release sheet 12a with a coating layer was obtained. Then, the coating liquid of the adhesive composition P is applied onto the peeling surface of the other release sheet 12b, and heat-treated to crosslink the adhesive composition P to form a coating layer, thereby obtaining a peeling of the coated layer. Sheet 12b. Further, the release sheet 12a with the coating layer and the release sheet 12b with the coating layer are bonded to each other so that the two coating layers are in contact with each other. When the aging period is required, the layered coating layer becomes the adhesive layer 11 by the aging period, and when the aging period is not required, the layered coating layer directly becomes the adhesive layer 11. Thereby, the above-mentioned adhesive sheet 1 is obtained. According to this manufacturing example, even when the adhesive layer 11 is thick, it can be stably manufactured.

As a method of applying the coating liquid of the above-described 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, or the like can be used.

(4) Adhesion

The lower limit of the adhesion of the adhesive sheet 1 to the soda lime glass of the present embodiment is preferably 5 N/25 mm or more, more preferably 8 N/25 mm or more, and still more preferably 10 N/25 mm or more. When the lower limit of the adhesive force of the adhesive sheet 1 is more than the above, it is excellent in the step-followability in the high-temperature and high-humidity conditions. On the other hand, the upper limit of the adhesive force is not particularly limited, and when it is considered that the peeling sheets 12a and 12b are easily peeled off from the adhesive layer 11 during use, 50 N/25 mm or less is preferable, and 30 N/25 mm or less is particularly preferable. good. Further, when reworkability is also considered, 26 N/25 mm or less is preferable. In this case, even if a misfit occurs, the display body constituent member can be easily reused.

Here, the adhesive force in the present specification basically means an adhesive force measured by a 180-degree peeling method according to JIS Z0237:2009, and the measurement sample is set to a width of 25 mm and a length of 100 mm, and the measurement sample is attached to the adhered sample. After pressurizing for 20 minutes at 0.5 MPa and 50 ° C, the mixture was allowed to stand under normal pressure, 23 ° C, and 50% RH for 24 hours, and then measured at a peeling speed of 300 mm/min.

[display body]

The display body of the present embodiment includes a first display body constituent member having a step on at least the surface on the side of the bonding, a second display body constituent member, and a first display member and a second display member. Adhesive layer. This adhesive layer is composed of the above-described adhesive of the present embodiment. In addition, the first display body constituent member and/or the second display body constituent member have electrodes on at least the side of the bonding (adhesive layer side). As a preferred configuration, the second display body constitutes a member to There are electrodes on the side that is less on the side of the fit.

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

The first display member constituting member may be a glass plate, a plastic plate or the like, and is preferably a protective panel including a laminate or the like. The first display member constituting member has a step on the surface on the side of the adhesive layer, and specifically, a step formed by the printed layer is preferable. The printed layer is generally formed in a frame shape.

The glass plate is not particularly limited, and examples thereof include chemically strengthened glass, alkali-free glass, quartz glass, soda lime glass, barium-containing glass, aluminosilicate glass, lead glass, and borosilicate glass. Bismuth borate glass and the like. The thickness of the glass plate is not particularly limited, and 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, and is usually 0.2 to 5 mm, and 0.4 to 3 mm is preferable.

Further, various functional layers (electrode layer, silicon oxide layer, hard coat layer, antiglare layer, etc.) may be provided on one or both sides of the glass plate or the plastic plate, or an optical member may be laminated.

The material constituting the printing layer is not particularly limited, and a known material for printing can be used. The thickness of the printed layer, that is, the lower limit of the height of the step is preferably 3 μm or more, more preferably 5 μm or more, particularly preferably 7 μm or more, and most preferably 10 μm or more. If the lower limit value is more than the above, it is difficult to visually recognize the electrical wiring. Observed on the side of the person can fully ensure concealment. Further, the upper limit is preferably 50 μm or less, more preferably 35 μm or less, particularly preferably 25 μm or less, and further preferably 20 μm or less. By the upper limit being the above value, it is possible to prevent deterioration of the step followability of the adhesive layer to the printed layer.

The second display member is a member to be bonded to the optical member and the display module of the first display member (for example, a liquid crystal (LCD) module, a light emitting diode (LED) module, or an organic electroluminescence ( The organic EL module or the like, the optical member which is a part of the display body module, or the laminated body including the display body module is preferably an electrode having at least the surface on the side of the 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.

Examples of the electrode include a metal electrode (including a mesh or a grid) made of copper or silver, a transparent conductive film (including a pattern) made of tin-doped indium oxide (ITO), or the like. As described above, among the above electrodes, a metal electrode mainly composed of an unoxidized metal, specifically, a metal electrode composed of copper or silver is preferable.

As an example of the display body of the present embodiment, a capacitive touch panel 2 is shown in FIG. 2 . The touch panel 2 is configured to include a display body module 3, a first film sensor 5a laminated thereon via an adhesive layer 4, and a second film sensing layered thereon via the first adhesive layer 11. The cover 5 is laminated on the second adhesive layer 11 above. Since the printed layer 7 is formed on the surface of the cover material 6 on the side of the second adhesive layer 11, there is a step formed by the presence or absence of the printed layer 7. In the present embodiment, the covering material 6 corresponds to the first one described above. The display body constituent member, and the second film sensor 5b corresponds to the second display body constituent member.

At least the second adhesive layer 11 of the touch panel 2 is the adhesive layer 11 of the adhesive sheet 1, and the first adhesive layer 11 and the second adhesive layer 11 are both adhered in consideration of the migration preventing effect. The adhesive layer 11 of the sheet 1 is preferred. In addition, when the first adhesive layer 11 is not the adhesive layer 11 of the adhesive sheet 1, an adhesive such as an acrylic adhesive, a rubber adhesive, or an anthrone may be mentioned as an adhesive constituting the first adhesive layer 11. An adhesive, a urethane-based adhesive, a polyester-based adhesive, a polyvinyl ether-based adhesive, etc., of which an acrylic adhesive is preferred.

The adhesive layer 4 may be formed of the adhesive layer 11 of the above-mentioned adhesive sheet 1, or may be formed of other adhesives or adhesive sheets. In the latter case, examples of the adhesive constituting the adhesive layer 4 include an acrylic adhesive, a rubber-based adhesive, an anthrone-based adhesive, a urethane-based adhesive, and a polyester-based adhesive. A polyvinyl ether-based adhesive or the like is preferred, and an acrylic adhesive is preferred.

The first film sensor 5a and the second film sensor 5b in the present embodiment each include a base film 51 and an electrode 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 can be used.

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

The electrode 52 of the first thin film sensor 5a and the electrode 52 of the second thin film sensor 5b are usually one circuit pattern constituting the X-axis direction, and the other is A circuit pattern in the Y-axis direction.

The electrode 52 of the second thin film sensor 5b in the present embodiment is located on the upper side of the second thin film sensor 5b in Fig. 2 . On the other hand, the electrode 52 of the first thin film sensor 5a is located above the first thin film sensor 5a in Fig. 2, but the invention is not limited thereto, and may be located on the lower side of the first thin film sensor 5a. .

Hereinafter, an example of the method of manufacturing the touch panel 2 will be described.

As the adhesive sheet 1, the first adhesive sheet 1 and the second adhesive sheet 1 are prepared. The peeling sheet 12a is peeled off from the first adhesive sheet 1, and the exposed adhesive layer 11 (first adhesive layer) is brought into contact with the electrode 52 of the first thin film sensor 5a and the first thin film sensor. 5a fits. Then, one release sheet 12a is peeled off from the second adhesive sheet 1, and the exposed adhesive layer 11 (second adhesive layer 11) is brought into contact with the electrode 52 of the second thin film sensor 5b and the second thin film. The sensor 5b is attached.

Further, the other one of the first adhesive sheets 12b is peeled off, and the exposed first adhesive layer 11 and the second thin film sensor 5b are opposite to the side on which the second adhesive layer 11 is laminated. The surface (the exposed surface of the base film 51 of the second film sensor 5b) is brought into contact with each other. Thereby, a laminate in which the release sheet 12b, the second adhesive layer 11, the second thin film sensor 5b, the first adhesive layer 11, and the first thin film sensor 5a are laminated in this order is obtained.

Then, the adhesive layer 4 provided on the release sheet is bonded to the surface of the laminate on the side of the first thin film sensor 5a (the exposed surface of the base film 51 of the first thin film sensor 5a). Then, the release sheet 12b is peeled off from the laminated body, and the exposed cover material 6 is bonded to the exposed second adhesive layer 11 so that the printed layer 7 side of the cover material 6 comes into contact with the second adhesive layer 11. At this time, the second adhesive layer 11 Since the step followability at the time of attaching is excellent, it is possible to suppress the occurrence of a gap and the floating in the vicinity of the step formed by the printed layer 7. By the above bonding, the cover material 6, the second adhesive layer 11, the second thin film sensor 5b, the first adhesive layer 11, the first thin film sensor 5a, the adhesive layer 4, and the release sheet can be obtained in order. A layered structure.

Finally, the release sheet is peeled off from the above-described constituent body, and the exposed adhesive layer 4 is brought into contact with the display module 3 so that the constituent body is bonded to the display module 3. Thereby, the touch panel 2 shown in FIG. 2 is manufactured.

Even in the case where 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 adhesive layer 11 in contact with the electrode 52 contains a decane coupling agent (B) derived from a mercapto group. The composition can effectively suppress the migration of the electrode 52. Thereby, it is possible to prevent the driving failure of the touch panel 2 caused by the disconnection and short circuit of the electrode 52.

Further, the pressure-sensitive adhesive layer 11 is excellent in step-followability even under high-temperature and high-humidity conditions, and therefore the touch panel 2 is exposed to high temperature and high humidity conditions for a predetermined period of time (for example, 72 hours at 85 ° C and 85% RH). In this case, it is also possible to effectively suppress generation of air bubbles, floating, peeling, and the like in the vicinity of the step formed by the printed layer 7.

The embodiments described above are described in order to facilitate the understanding of the present invention, and are not intended to limit the present invention. Therefore, the various embodiments disclosed in the above embodiments are intended to encompass all design changes and equivalents of the technical scope of the invention.

For example, any one of the release sheets 12a, 12b in the adhesive sheet 1 can be omitted.

[Examples]

Hereinafter, the present invention will be specifically described by way of examples, but the scope of the present invention is not limited to the examples and the like.

[Example 1]

1. Preparation of (meth) acrylate copolymer

The (meth) acrylate polymer (A) was prepared by copolymerizing 60 parts by mass of 2-ethylhexyl acrylate, 20 parts by mass of methyl methacrylate, and 20 parts by mass of 2-hydroxyethyl acrylate. The molecular weight of the (meth) acrylate polymer (A) was measured by the method described later, and the weight average molecular weight (Mw) was 600,000.

2. Preparation of adhesive composition

100 parts by mass of the (meth) acrylate polymer (A) obtained in the above Process 1 (solid content conversion value; the same applies hereinafter), 3-mercaptopropyltrimethoxy which is a decane-based decane coupling agent (B) Co-condensation product of decane and methyltriethoxy decane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "X-41-1810", oligomer type, thiol equivalent: 450 g/mol) 0.05 0.2 parts by mass of trimethylolpropane-modified toluene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., product name "Coronate L") as a crosslinking agent (C), and thoroughly stirred and utilized Methyl ethyl ketone was diluted to obtain a coating solution of an adhesive composition having a solid content concentration of 38% by mass.

In the above, the respective components (solid content conversion values) of the adhesive composition when the (meth) acrylate polymer (A) is 100 parts by mass (solid content conversion value) are shown in Table 1. The details of the abbreviations and the like described in Table 1 are as follows.

[(Meth)acrylate polymer (A)]

2EHA: 2-ethylhexyl acrylate

MMA: Methyl methacrylate

HEA: 2-hydroxyethyl acrylate

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

X-41-1810: a cocondensate of 3-mercaptopropyltrimethoxydecane and methyltriethoxydecane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "X-41-1810"), Polymer type, thiol equivalent: 450g/mole)

KBM-803: 3-mercaptopropyltrimethoxydecane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "KBM-803", low molecular weight, thiol equivalent: 196.4 g/mole)

[Other decane coupling agents]

KBM-403: 3-glycidyloxypropyltrimethoxydecane (manufactured by Shin-Etsu Silicone Co., Ltd., trade name "KBM-403", low molecular type)

KBE-9007: 3-isocyanate propyl triethoxy decane (manufactured by Shin-Etsu Silicone Co., Ltd., trade name "KBE-9007", low molecular type)

3. Manufacture of adhesive sheets

A peeling treatment of a heavy release type release sheet (manufactured by LINTEC Corporation, trade name "SP-PET382150", thickness: 38 μm) obtained by peeling one surface of a polyethylene terephthalate film with an anthrone-based release agent On the surface, the coating solution of the adhesive composition obtained in the above Process 2 was applied by a knife coater, and then heat-treated at 90 ° C for 1 minute to form a coating layer (thickness: 25 μm). In the same manner, a peeling-treated surface of a light-peelable release sheet (manufactured by LINTEC Corporation, product name "SP-PET382120") obtained by peeling one surface of a polyethylene terephthalate film with an anthrone-based release agent Applying the adhesiveness obtained in the above process 2 by a doctor blade coater After the coating solution of the composition, heat treatment was performed at 90 ° C for 1 minute to form a coating layer (thickness: 25 μm).

Then, the heavy release release sheet with the coating layer obtained in the above and the light release release sheet with the coating layer obtained above are bonded together so that the two coating layers are in contact with each other, and After aging for 7 days under conditions of 23 ° C and 50% RH, an adhesive sheet composed of a heavy release type release sheet/adhesive layer (thickness: 50 μm) / light release type release sheet was produced.

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

In the same manner as in Example 1, except that the type and ratio of the decane coupling agent (the decane coupling agent (B) having a mercapto group and the other decane coupling agent) and the ratio of the crosslinking agent (C) were changed as shown in Table 1. Make adhesive sheets. Further, for Comparative Examples 7 to 10, N,N-bis(2-ethylhexyl)-(4 or 5)-methyl-1H-benzotriazole-1-methylamine (trade name, manufactured by BASF Corporation) "IRGMET 39") was incorporated as a rust inhibitor in the adhesive composition in the proportions shown in Table 1.

Here, the weight average molecular weight (Mw) is a polystyrene-equivalent weight average molecular weight measured by gel permeation chromatography (GPC) under the following conditions (GPC measurement).

<Measurement conditions>

‧GPC measuring device: manufactured by TOSOH CORPORATION, HLC-8020

‧GPC column (passed in the following order): TOSOH CORPORATION

TSK guard column HXL-H

TSK gel GMHXL (×2)

TSK gel G2000HXL

‧ Determination of solvent: tetrahydrofuran

‧Measurement temperature: 40 ° C

[Test Example 1] (Measurement of gel fraction)

The adhesive sheets obtained in the examples and the comparative examples were cut into a size of 80 mm × 80 mm, and the adhesive layer was wrapped in a polyester mesh (mesh size 200), and the mass was weighed by a precision balance, minus The quality of the above-mentioned net alone is used to calculate the quality of the adhesive itself. Set the quality at this time to M1.

Next, the adhesive wrapped in the above polyester web was immersed in ethyl acetate at room temperature (23 ° C) for 24 hours. Thereafter, the adhesive was taken out, air-dried for 24 hours in an environment of a temperature of 23 ° C and a relative humidity of 50%, and dried in an oven at 80 ° C for 12 hours. After drying, the quality of the adhesive itself is calculated by weighing the mass by a precision balance and subtracting the individual mass of the above net. Set the quality at this time to M2. The gel fraction (%) is represented by (M2/M1) × 100. The results are shown in Table 2.

[Test Example 2] (Measurement of adhesion)

The light release type release sheet was peeled off from the adhesive sheets obtained in the examples and the comparative examples, and the exposed adhesive layer was attached to a polyethylene terephthalate (PET) film having an easy adhesion layer (TOYOBO CO.). An easy-to-adhere layer of the product name "PET A4300", thickness: 100 μm, manufactured by LTD., to obtain a laminate of a heavy release release sheet/adhesive layer/PET film. The obtained laminate was cut into a width of 25 mm and a length of 100 mm, and this was used as a sample.

The peel-off release sheet was peeled off from the above sample in an environment of 23 ° C and 50% RH, and the exposed adhesive layer was attached to soda lime glass (manufactured by Nippon Sheet Glass Co., Ltd.), and KURIHARA CORPORATION was used. The autoclave was pressurized at 0.5 MPa and 50 ° C for 20 minutes. Thereafter, at 23 After standing for 24 hours at a temperature of 50% RH, the adhesion was measured under a condition of a peeling speed of 300 mm/min and a peeling angle of 180 degrees using a tensile tester (TENSILON, manufactured by ORIENTEC Co., LTD.) (N/25 mm). ). The 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) Manufacturing of wiring board

A copper-clad laminate (manufactured by NIKKAN INDUSTRIES Co., Ltd., product name "NIKAFLEX") laminated with a copper foil (thickness: 18 μm) and a polyethylene terephthalate film (thickness: 50 μm) On the foil surface, an etch resist pattern is printed by screen printing. Thereafter, the comb-shaped electrode is formed by etching to remove the unnecessary copper foil. The line width of each electrode was 300 μm, and the gap between the electrodes was 50 μm.

(2) Evaluation of migration prevention effect

The light release release sheet was peeled off from the adhesive sheets obtained in the examples and the comparative examples, and the exposed adhesive layer was attached to a polyethylene terephthalate (PET) film having an easy adhesion layer (TOYOBO CO.). An easy-to-adhere layer of the product name "PET A4300", thickness: 100 μm, manufactured by LTD., to obtain a laminate of a heavy release release sheet/adhesive layer/PET film. Next, the heavy release type release sheet was peeled off from the laminated body, and the exposed adhesive layer was attached to the above-mentioned comb-shaped electrode, and this was used as a sample.

The sample was allowed to stand under humid heat conditions of 85 ° C and 85% RH, and a voltage of 5 V was applied between the electrodes in this state to carry out a migration test. The comb-shaped electrode was observed by an optical microscope (magnification: 10 times) after 8 hours, 24 hours, and 48 hours from the start of the test, and evaluated based on the evaluation criteria shown below. Migration prevention effect. The results are shown in Table 2.

◎: Dissolution of the electrode (positive electrode) and formation of dendrite crystals in the electrode (negative electrode) were not observed at all.

○: Dissolution was observed only at the end of the electrode (positive electrode), and no branch crystal was observed in the electrode (negative electrode).

×: Dissolution of the electrode (positive electrode) and formation of dendrite crystals in the electrode (negative electrode) were observed.

In addition, the reference image of the above evaluation criteria is shown in FIG.

[Test Example 4] (Evaluation of the step followability)

(a) Production of samples for evaluation

Surface-printing UV-curable ink (Teikoku Printing Inks Mfg. Co., manufactured by NSG Precision Co., Ltd., product name "Corning Glass EAGLE XG", vertical 90 mm × width 50 mm × thickness 0.5 mm) The product name "POS-911 ink" manufactured by Ltd. has a frame shape of any of 5 μm, 10 μm, and 15 μm (outer shape: vertical 90 mm × width 50 mm, width 5 mm). Next, ultraviolet rays (80 W/cm ² , two metal halide lamps, a lamp height of 15 cm, and a belt speed of 10 to 15 m/min) were irradiated to harden the printed ultraviolet curable ink, thereby producing by printing. A glass plate with a step difference (the height of the step: any one of 5 μm, 10 μm, and 15 μm).

The light release release sheet was peeled off from the adhesive sheets obtained in the examples and the comparative examples, and the exposed adhesive layer was attached to a polyethylene terephthalate film having an easy adhesion layer (TOYOBO Co., Ltd.) . Manufacture, PET A4300, thickness: 100 μm) easy adhesion layer. Next, the heavy release type release sheet was peeled off, and the adhesive layer before hardening was peeled off. After that, using a laminator (manufactured by FUJIPLA Inc., The product name "LPD3214") is formed by molding the above-mentioned laminated body to each of the glass plates with the step difference so that the adhesive layer covers the entire printing surface of the frame.

(b) Evaluation of samples for evaluation

The obtained evaluation sample was subjected to an autoclave treatment at 50 ° C and 0.5 MPa for 30 minutes, and then left at normal pressure, 23 ° C, and 50% RH for 24 hours. Next, it was stored under the endurance conditions of 85 ° C and 85% RH for 72 hours. Thereafter, the adhesive layer (especially in the vicinity of the step formed by the printed layer) was visually confirmed, and the step followability was evaluated in accordance with the following criteria. The results are shown in Table 2.

◎: There are no bubbles at all and floating.

○: Less than 10 bubbles were observed in the vicinity of the step.

×: There are bubbles and/or floating.

[Test Example 5] (Evaluation of resistance to wet heat whitening)

The adhesive layer of the adhesive sheet obtained in the Example or the comparative example was sandwiched by two sheets of alkali-free glass having a thickness of 1.1 mm to obtain a laminate, which was used as a sample. The obtained sample was stored under the conditions of 85 ° C and 85% RH for 120 hours. Thereafter, normal temperature and humidity of 23° C. and 50% RH were recovered, and the presence or absence of whitening was visually observed according to the following criteria, and the wet heat whitening resistance was evaluated, and the haze value of the adhesive layer was measured. With respect to the haze value, the sample was returned to normal temperature and humidity, and the measurement was carried out in accordance with JIS K7136:2000 using a haze meter (manufactured by NIPPON DENSHOKU INDUSTRIES Co., LTD., product name "NDH2000") within 30 minutes. The results are shown in Table 2.

○: Whitening was not confirmed even after returning to normal temperature and humidity. Or, part of it will be whitened, but it will disappear within 30 minutes.

×: The overall whitening occurred. Or, after a part of whitening occurs, it cannot be restored to its original state even if it is stored under normal temperature and humidity.

As is clear from Table 2, any of the adhesive sheet migration preventing effect, the step followability, and the moist heat whitening property obtained in the examples was excellent.

[Industrial availability]

The adhesive composition, the adhesive, and the adhesive sheet of the present invention can be preferably used, for example, in a capacitive touch panel using a copper electrode or a silver electrode. Further, the display body of the present invention is preferably used as a capacitive touch panel using a copper electrode or a silver electrode, for example.

1‧‧‧Adhesive film

11‧‧‧Adhesive layer before hardening

12a, 12b‧‧‧ peeling film

Claims (10)

An adhesive composition comprising an adhesive for bonding a first display member constituting member and a second display member constituting member having a step at least on a surface of the bonding side, wherein the first display member constituting member and The second display member constituting member has an electrode on at least the surface on the bonding side, and the adhesive composition contains a (meth) acrylate polymer (A) and a decane coupling agent (B) having a mercapto group. The adhesive composition according to claim 1, wherein the decane coupling agent (B) having a mercapto group is a mercapto group-containing oligomer-type decane coupling agent. The adhesive composition according to claim 1, wherein the sulfhydryl equivalent of the organic hydrazine compound constituting the decane coupling agent (B) having a mercapto group is 100 g/mol or more and 1000 g/mole or less. The adhesive composition according to claim 1, wherein the content of the decane coupling agent (B) having a mercapto group in the adhesive composition is relative to the (meth)acrylate polymer (A). 100 parts by mass is 0.01 parts by mass or more and 5 parts by mass or less. The adhesive composition according to claim 1, wherein the (meth) acrylate polymer (A) is contained in an amount of 3% by mass or more and 35% by mass or less as a monomer unit constituting the polymer. Hydroxyl containing monomer. The adhesive composition according to claim 1, wherein the adhesive composition further contains a crosslinking agent (C). An adhesive which is obtained by crosslinking the adhesive composition according to any one of claims 1 to 6. An adhesive sheet having an adhesive layer composed of the adhesive described in claim 7 of the patent application. The adhesive sheet according to claim 8, wherein the adhesive sheet comprises two release sheets, and the adhesive layer is sandwiched by the release sheet so as to be in contact with the peeling surface of the two release sheets. A display body comprising: a first display body constituting member having a step at least on a surface on a bonding side; a second display body constituting member; and an adhesive layer constituting the first display constituting member and the second display body The display member is characterized in that the first display member constituting member and/or the second display member constituting member have electrodes on at least the surface on the bonding side, and the adhesive layer is the eighth item of the patent application. The adhesive layer of the adhesive sheet.