TWI772262B - adhesive sheet - Google Patents

Abstract

The present invention provides a migration inhibitor, an adhesive and an adhesive sheet which can effectively prevent and inhibit migration. The migration inhibitor contains a silane coupling agent having a mercapto group, the adhesive is obtained from an adhesive composition containing the migration inhibitor, and the adhesive sheet includes an adhesive layer composed of the adhesive. It is preferable that the said adhesive composition contains the (meth)acrylate polymer (A) and the silane coupling agent (B) which has a mercapto group as the said migration inhibitor.

Description

adhesive sheet

The present invention relates to an anti-migration agent, an adhesive, and an adhesive sheet capable of preventing and suppressing migration of metal members and the like such as metal electrodes of a touch panel.

In recent years, in various mobile electronic devices such as smartphones and tablet computers, touch panels are often used as displays. As the method of the touch panel, there are a resistive film method, an electrostatic capacitance method, and the like, and the electrostatic capacitance method is mainly used in the above-mentioned mobile electronic devices.

The size of touch panels has recently been increased, and mesh-like metal electrodes, such as copper electrodes or silver electrodes, are being studied as electrode materials for such touch panels. 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 dissolves to cause disconnection, or in the negative electrode, dendrites are formed by precipitation of the positive electrode component, and short circuit occurs.

This migration is particularly likely to occur when a voltage is applied to the electrode under high temperature and high humidity. If such migration occurs, the touch panel cannot be driven normally. Especially recently, the miniaturization and narrow pitch of electrodes are progressing, and disconnection and short-circuiting of electrodes due to migration are likely to occur.

However, Patent Document 1 has disclosed an adhesive composition for touch panels containing a benzotriazole compound as a rust inhibitor.

【Prior technical literature】 【Patent Literature】

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

However, even if a benzotriazole compound as a rust inhibitor has an anti-corrosion effect of metal wiring, it cannot sufficiently prevent and suppress migration.

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

In order to achieve the above object, first, the present invention provides an anti-migration agent characterized by containing a silane coupling agent having a mercapto group (Invention 1).

According to the above invention (Invention 1), when the material to which the migration inhibitor is added comes into contact with a target member such as a metal member such as a metal electrode of a touch panel, migration in the target member can be effectively prevented and suppressed.

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

In the above inventions (Inventions 1 and 2), the mercapto equivalent weight of the organosilicon compound constituting the silane coupling agent is preferably 100 g/mol or more and 1000 g/mol or less (Invention 3).

Second, the present invention provides an adhesive, which is characterized in that: An adhesive composition having the aforementioned migration inhibitor (Inventions 1 to 3) was obtained (Invention 4).

In the above invention (Invention 4), it is preferable that the adhesive composition contains a (meth)acrylate polymer (A) and a mercapto-group-containing silane coupling agent (B) as the migration inhibitor (Invention 5).

In the above invention (Invention 5), the (meth)acrylate polymer (A) preferably contains a hydroxyl group-containing monomer in an amount of 3 mass % or more and 35 mass % or less as a monomer unit constituting the polymer (Invention 6).

In the above inventions (Inventions 5 and 6), it is preferable that the adhesive composition further contains a crosslinking agent (C) (Invention 7).

In the above inventions (Inventions 5 to 7), the content of the silane coupling agent (B) having a mercapto group in the adhesive composition is 0.01 mass with respect to 100 parts by mass of the (meth)acrylate polymer (A) Parts or more and 5 parts by mass or less are preferred (Invention 8).

Third, the present invention provides an adhesive sheet, which is characterized by comprising: two peeling sheets; and an adhesive layer, which is sandwiched by the peeling sheets in a manner of contacting the peeling surfaces of the two peeling sheets, and the adhesive layer is It consists of the aforementioned adhesives (Inventions 4 to 8) (Invention 9).

In the above invention (Invention 9), it is preferable that the adhesive layer is arranged on the touch panel so as to be in contact with the electrodes (Invention 10).

The migration inhibitor, the adhesive and the adhesive sheet according to the present invention can effectively prevent and inhibit migration.

1‧‧‧Adhesive Sheet

11‧‧‧Adhesive layer

12a, 12b‧‧‧Peeling sheet

2‧‧‧Touch Panel

3‧‧‧Display Module

4‧‧‧Adhesive layer

5a‧‧‧First Thin Film Sensor

5b‧‧‧Second film sensor

51‧‧‧Substrate film

52‧‧‧Printed layer

6‧‧‧Covering material

7‧‧‧Printing layer

Fig. 1 is a cross-sectional view of 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 in Test Example 3. FIG.

Hereinafter, embodiments of the present invention will be described.

[Migration inhibitor]

The migration inhibitor according to one embodiment of the present invention contains a mercapto group-containing silane coupling agent. The anti-migration agent of this embodiment may consist of only the silane coupling agent which has a mercapto group, and may contain other components.

The anti-migration agent of the present embodiment is added to a material (hereinafter, sometimes referred to as a "contact material") that is in contact with a member (hereinafter, sometimes referred to as a "target member") that requires prevention and suppression of migration, and is used as better. Examples of the target member include metal electrodes (including mesh) made of copper, silver, etc., transparent conductive films (including patterned ones) made of tin-doped indium oxide (ITO), etc., Line film, wire grid polarizing film, etc. Among the above-mentioned metal electrodes, a metal electrode mainly composed of an unoxidized metal, specifically, a metal electrode composed of copper or silver is preferably used as a target member. Moreover, as said contact material, in addition to the adhesive agent mentioned later, an adhesive agent, a hard coat agent, etc. are mentioned, for example.

When the contact material to which the migration inhibitor containing the silane coupling agent is added is in contact with the target member, the silane coupling agent having a mercapto group can prevent and suppress the dissolution of the electrode in the positive electrode, and can prevent and suppress the formation of dendrites in the negative electrode. That is, migration in the target member can be effectively prevented and suppressed (this effect may be referred to as a "migration prevention effect"). Thereby, even if, for example, the electrodes are The target member with thin and narrow pitch can also prevent the disconnection and short circuit of the electrode. In particular, when the target member is the electrode of the touch panel, it is possible to prevent the drive failure of the touch panel caused by the disconnection and short circuit of the electrode.

The silane coupling agent 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. When the target member is an optical member such as a touch panel, the silane coupling agent having a mercapto group is preferably one having light transmittance, for example, one that is substantially transparent.

Specific examples of the silane coupling agent having a mercapto group include mercapto-group-containing 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, and 3-mercaptopropyldimethoxymethylsilane. Low molecular weight silane coupling agent; 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyldimethoxymethylsilane and other mercapto-containing silane compounds and methyl Oligomeric silane coupling agents containing mercapto groups, such as co-condensates of alkyl-containing silane compounds such as triethoxysilane, ethyltriethoxysilane, methyltrimethoxysilane, and ethyltrimethoxysilane, etc. . Among them, mercapto group-containing oligomer-type silane coupling agents with more excellent migration prevention effect and good workability are preferred, and co-condensates of mercapto group-containing silane compounds and alkyl group-containing silane compounds are particularly preferred, 3-mercaptopropane Cocondensates of methyltrimethoxysilane and methyltriethoxysilane are further preferred. These may be used individually by 1 type, and may be used in combination of 2 or more types.

The lower limit of the mercapto group equivalent of the organosilicon compound constituting the mercapto group-containing silane coupling agent is preferably 100 g/mol or more, particularly preferably 120 g/mol or more, and even more preferably 150 g/mol or more. By setting the lower limit as described above, when the contact material is used as the adhesive, the polarity difference from the polymer component serving as the main agent can be set within an appropriate range, and the above-mentioned silane coupling agent can be The dispersibility in the adhesive is better.

The upper limit of the mercapto group equivalent of the organosilicon compound constituting the mercapto group-containing silane coupling agent is preferably 1000 g/mol or less, particularly preferably 800 g/mol or less, and even more preferably 500 g/mol or less. By setting the upper limit as described above, when the contact material is used as the adhesive, deterioration of optical properties due to phase separation from the polymer component serving as the main agent can be prevented.

Regarding the addition amount of the migration inhibitor with respect to the contact material, the lower limit of the content of the component derived from the mercapto group-containing silane coupling agent in the contact material is preferably 0.01 mass % or more, and preferably 0.05 mass % or more. It is especially preferable, and it is more preferable that it is 0.1 mass % or more. In addition, regarding the above-mentioned addition amount, the upper limit of the content of the above-mentioned components in the contact material is preferably 5 mass % or less, particularly preferably 2.5 mass % or less, and further preferably 1 mass % or less. better. When the addition amount of the migration inhibitor is in the above-mentioned range, the migration prevention effect is more excellent.

(adhesive)

The adhesive of this embodiment is obtained from the adhesive composition containing the aforementioned migration inhibitor. The type of the adhesive is not particularly limited as long as it can exhibit the effect of preventing migration by the migration inhibitor. For example, acrylic adhesives, rubber-based adhesives, silicone-based adhesives, and urethane-based adhesives can be used. any of adhesives, polyester-based adhesives, polyvinyl ether-based adhesives, etc. In addition, the adhesive may be any one of an emulsion type, a solvent type, or a solventless type, or any one of a cross-linked type or a non-cross-linked type. Furthermore, it may be either an active energy ray curable type or an active energy ray non-curable type.

When the target member is an electrode of a touch panel, in the above, C An alkene-based adhesive is preferred. In this case, the adhesive of the present embodiment is composed of an adhesive composition containing a (meth)acrylate polymer (A) and a mercapto group-containing silane coupling agent (B) as the migration inhibitor (hereinafter, there are It is called "adhesive composition P".) The one obtained is better. It is preferable that the adhesive composition P further contains a crosslinking agent (C). In this case, the adhesive of the present embodiment is obtained by crosslinking the adhesive composition P. In addition, in this specification, (meth)acrylate means both acrylate and methacrylate. The same applies to other similar terms. In addition, the concept of "copolymer" is also included in "polymer".

The adhesive layer composed of the adhesive composed of the adhesive composition P containing the mercapto group-containing silane coupling agent (B) not only exhibits the above-mentioned migration preventing effect, but also has a mercapto group-derived substance at the interface with the target member. The component of the silane coupling agent (B) has high adhesion to the target member, and when the target member has a level difference, it is excellent in step followability. Specifically, even when the adhesive layer is attached to a target member having a level difference and exposed to high temperature and high humidity conditions for a predetermined time (for example, 72 hours at 85° C. and 85% RH), it is possible to suppress the Bubble, floating, peeling, etc. are generated near the step (excellent step followability under high temperature and high humidity conditions). Thereby, when the target member is a touch panel, reflection loss of light in the vicinity of the level difference can be suppressed, and the image quality of the touch panel can be maintained favorably.

(1) (Meth)acrylate polymer (A)

(Meth)acrylate polymer (A) can exhibit better adhesion by using alkyl (meth)acrylate having an alkyl group of 1 to 20 carbon atoms as a monomer unit constituting the polymer . From such a viewpoint, the number of carbon atoms in which the (meth)acrylate polymer (A) contains an alkyl group whose lower limit is 50 mass % or more is 1-20 alkyl (meth)acrylate is preferable as a monomer unit which comprises this polymer, 60 mass % or more is especially preferable, and 70 mass % or more is more preferable. When 50 mass % or more of said alkyl (meth)acrylates are contained, the (meth)acrylate polymer (A) can exhibit favorable adhesiveness. In addition, the (meth)acrylate polymer (A) preferably contains the above-mentioned alkyl (meth)acrylate having an upper limit of 97% by mass or less as a monomer unit constituting the polymer, preferably 90% by mass The following is particularly preferred, and the content of 85% by mass or less is further preferred. By containing 97 mass % or less of the said alkyl (meth)acrylate, the other monomer component of a preferable amount can be introduce|transduced into (meth)acrylate polymer (A).

Examples of alkyl (meth)acrylates having 1 to 20 carbon atoms in the alkyl group include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, and (meth)acrylate. Base) n-butyl acrylate, n-pentyl (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, cetyl (meth)acrylate, octadecyl (meth)acrylate, ( Cyclohexyl meth)acrylate, isobornyl (meth)acrylate, adamantyl (meth)acrylate, etc., among them, from the viewpoint of further improving the adhesiveness, those having an alkyl group having 4 to 8 carbon atoms (Meth)acrylates are preferred. These may be used alone or in combination of two or more. In addition, 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.

In addition, (meth)acrylic acid alkyl esters having 1 to 20 carbon atoms as an alkyl group, when used in combination as a homopolymer, have a glass transition temperature (Tg) exceeding 0 Also preferable are hard monomers whose temperature is 70°C or higher and soft monomers whose glass transition temperature (Tg) as a homopolymer is 0°C or lower. This is because the adhesiveness and flexibility are maintained by the soft monomer, and the cohesive force is improved by the hard monomer, thereby enabling a display panel (touch panel) to be more excellent in step followability. When comparing, the mass ratio of hard monomer to soft monomer is preferably 5:95~40:60, especially 20:80~30:70.

Examples of the hard monomers include methyl acrylate (Tg10°C), methyl methacrylate (Tg105°C), isobornyl acrylate (Tg94°C), isobornyl methacrylate (Tg180°C), acrylic acid Adamantyl ester (Tg115°C), adamantyl methacrylate (Tg141°C), etc. These may be used alone or in combination of two or more.

Among the above-mentioned 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 monomers . If tackiness is also considered, methyl acrylate and methyl methacrylate are more preferable, and methyl methacrylate is especially preferable.

As said soft monomer, the alkyl acrylate which has a C2-C12 linear or branched alkyl group is mentioned preferably. For example, 2-ethylhexyl acrylate (Tg-70 degreeC), n-butyl acrylate (Tg-54 degreeC) etc. are mentioned preferably. These may be used alone 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 reacts with a crosslinking agent (C) to be described later to form a crosslinked structure (three-dimensional network structure), and a desired product can be obtained. Cohesive adhesive.

As the reactive functional group-containing monomer contained in the (meth)acrylate polymer (A) as a monomer unit constituting the polymer, a monomer having a hydroxyl group in the molecule (hydroxyl group-containing monomer) is preferably used. monomers), monomers with carboxyl groups in the molecule (carboxyl group-containing monomers), monomers with amine groups in the molecules (amine group-containing monomers), and the like. Among these, the hydroxyl-containing monomer which is excellent in the reactivity with the crosslinking agent (C) and the wet-heat whitening resistance and has little adverse effect on the electrode of the target member is particularly preferable.

Examples of hydroxyl-containing monomers include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 2-hydroxypropyl (meth)acrylate. Hydroxyalkyl (meth)acrylates such as hydroxybutyl, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and the like. 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 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 from the viewpoint of reactivity with the crosslinking agent (C) and the reactivity of the carboxyl group in the obtained (meth)acrylate polymer (A) and copolymerizability with other monomers. These may be used alone or in combination of two or more.

As an amino group-containing monomer, aminoethyl (meth)acrylate, n-butylaminoethyl (meth)acrylate, etc. are mentioned, for example. These may be used alone or in combination of two or more.

The lower limit of the content of the (meth)acrylate polymer (A) is 3 mass The hydroxyl group-containing monomer is preferably contained in an amount of % or more as a monomer unit constituting the polymer, particularly preferably 10% by mass or more, and even more preferably 15% by mass or more. Further, the (meth)acrylate polymer (A) preferably contains a hydroxyl group-containing monomer having an upper limit of 35% by mass or less as a monomer unit constituting the polymer, particularly preferably 30% by mass or less, and contains 25 mass % or less is more 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 hydroxyl groups will remain in the obtained adhesive. Hydroxyl is a hydrophilic group. If the hydrophilic group exists in the adhesive in a predetermined amount, even if the adhesive is placed under high temperature and high humidity conditions, it will be different from the moisture immersed in the adhesive under the high temperature and high humidity conditions. The compatibility is also good, and as a result, the whitening of the adhesive at the time of returning to normal temperature and normal humidity can be suppressed (excellent in wet-heat whitening resistance).

However, when a predetermined amount of the hydrophilic group exists in the adhesive as described above, the adhesive tends to absorb water, and migration tends to occur in the target member in contact with the adhesive. However, the adhesive composition P of the present embodiment can effectively prevent and suppress the occurrence of migration in the target member in contact by containing the silane coupling agent (B) having a mercapto group as a migration inhibitor.

It is preferable that the (meth)acrylate polymer (A) does not contain a carboxyl group-containing monomer as a monomer unit constituting the polymer, but a predetermined amount is allowed. This is because the migration of the target member is generally concerned due to the carboxyl-based acid component, but the adhesive of this embodiment is obtained from the adhesive composition P containing the silane coupling agent (B) having a mercapto group as a migration inhibitor. , even if there is a carboxyl group, the effect of preventing migration can be exhibited. Specifically, in the (meth)acrylate polymer (A), the carboxyl group-containing monomer is contained in an amount of 5 mass % or less as a monomer unit, and the carboxyl group-containing monomer is preferably contained in an amount of 2 mass % or less. .

The (meth)acrylate polymer (A) may contain other monomers as monomeric units constituting the polymer as needed. As other monomers, in order not to hinder the action of the reactive functional group-containing monomer, it is preferable to use a monomer that does not contain a reactive functional group. Examples of such other monomers include alkoxyalkyl (meth)acrylates such as methoxyethyl (meth)acrylate and ethoxyethyl (meth)acrylate, and (meth)acrylic acid N,N-dimethylaminoethyl ester, (meth)acrylic acid N,N-dimethylaminopropyl ester, (meth)acryloyl morpholine and other non-crosslinkable tertiary amine groups (Meth)acrylate, (meth)acrylamide, dimethylacrylamide, vinyl acetate, styrene, and the like. These may be used alone 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, particularly preferably 300,000 or more, and even more preferably 400,000 or more. In addition, the weight average molecular weight in this specification is a standard polystyrene conversion value measured by gel permeation chromatography (GPC). If the lower limit of the weight average molecular weight of the (meth)acrylate polymer (A) is the above or more, the adhesive will be excellent in step followability under high temperature and high humidity conditions.

In addition, the upper limit of the weight average molecular weight of the (meth)acrylate polymer (A) is preferably 1 million or less, particularly preferably 900,000 or less, and even more preferably 700,000 or less. If the upper limit of the weight average molecular weight of the (meth)acrylate polymer (A) is the above-mentioned or less, the adhesive will be excellent in step followability at the time of sticking.

In addition, in the adhesive composition P, (meth)acrylate A polymer (A) may be used individually by 1 type, and may be used in combination of 2 or more types.

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

The silane coupling agent (B) having a mercapto group contained in the adhesive composition P is a silane coupling agent having a mercapto group as the aforementioned migration inhibitor.

The content of the mercapto group-containing silane coupling agent (B) in the adhesive composition P is preferably 0.01 parts by mass or more, preferably 0.05 parts by mass, relative to 100 parts by mass of the (meth)acrylate polymer (A). part or more is particularly preferred, and 0.1 part by mass or more is further preferred. In addition, the upper limit is preferably 5 parts by mass or less, particularly preferably 1.5 parts by mass or less, and even more preferably 1.0 parts by mass or less. When the content of the mercapto group-containing silane coupling agent (B) is in the above-mentioned range, the effect of preventing migration becomes more excellent.

The lower limit of the molar number (mercapto group content) of the mercapto group in the silane coupling agent (B) per 100 g of the (meth)acrylate polymer (A) is preferably 0.01 mmol or more, particularly preferably 0.1 mmol or more, 0.2 mmol or more is more preferable. In addition, the upper limit of the molar number is preferably 30 mmol or less, particularly preferably 5 mmol or less, and further preferably 1.5 mmol or less. When the molar number of the mercapto group of the silane coupling agent (B) with respect to the (meth)acrylate polymer (A) is in the above-mentioned range, it can be set as one having a more excellent effect of preventing migration.

(3) Cross-linking agent (C)

It is preferable that the adhesive composition P contains a crosslinking agent (C). The adhesive composition P contains a cross-linking agent (C) to cross-link the (meth)acrylate polymer (A) to form a three-dimensional network structure, which can improve the cohesion of the obtained adhesive, thereby improving high temperature and high temperature. Step followability in wet conditions.

As the crosslinking agent (C), as long as it is polymerized with (meth)acrylate The reactive group possessed by the compound (A) may be reacted, for example, an isocyanate-based crosslinking agent, an epoxy-based crosslinking agent, an amine-based crosslinking agent, a melamine-based crosslinking agent, and an aziridine-based crosslinking agent may be mentioned. Cross-linking agent, hydrazine-based cross-linking agent, aldehyde-based cross-linking agent, oxazoline-based cross-linking agent, metal alkoxide-based cross-linking agent, metal chelate-based cross-linking agent, metal salt-based cross-linking agent, ammonium salt Department of cross-linking agents, etc. When the (meth)acrylate polymer (A) contains a hydroxyl group-containing monomer as a monomer unit constituting the polymer, it is preferable to use an isocyanate-based crosslinking agent having excellent reactivity with the hydroxyl group. In addition, the crosslinking agent (C) may be used alone or in combination of two or more.

The isocyanate-based crosslinking agent contains at least a polyisocyanate compound. Examples of the polyisocyanate compound include aromatic polyisocyanates such as toluene diisocyanate, diphenylmethane diisocyanate, and xylylene diisocyanate, aliphatic polyisocyanates such as hexamethylene diisocyanate, and isophorone diisocyanate. , alicyclic polyisocyanates such as hydrogenated diphenylmethane diisocyanate, etc., and their biuret, isocyanurate, and ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, castor Sesame oil, etc. as adducts with reactants containing low molecular active hydrogen compounds, etc. Among them, from the viewpoint of reactivity with hydroxyl groups, trimethylolpropane-modified aromatic polyisocyanates are preferable, and trimethylolpropane-modified toluene diisocyanate is particularly preferable.

The content of the crosslinking agent (C) in the adhesive composition P is preferably 0.001 parts by mass or more, particularly 0.01 parts by mass or more, relative to 100 parts by mass of the (meth)acrylate polymer (A). Preferably, 0.02 mass part or more is further preferable. In addition, the upper limit is preferably 10 parts by mass or less, particularly preferably 5 parts by mass or less, and even more preferably 1 part by mass or less.

When the content of the crosslinking agent (C) is in the above-mentioned range, the obtained The better cohesion of the adhesive is obtained, and the step followability of the adhesive under high temperature and high humidity conditions is improved.

(4) Various additives

Various additives commonly used in acrylic adhesives, such as antistatic agents, tackifiers, antioxidants, ultraviolet absorbers, light stabilizers, softeners, fillers, refractive index, can be added to the adhesive composition P as required. adjuster, etc. Moreover, in addition to the silane coupling agent (B) which has a mercapto group mentioned above, other silane coupling agent was added at the same time. However, since a rust inhibitor, especially a benzotriazole-based rust inhibitor, has an effect of inhibiting the crosslinking of the adhesive composition P, it is preferable not to add it.

In addition, the adhesive composition P may contain active energy ray-curable components such as polyfunctional acrylate-based monomers having a molecular weight of less than 1,000 as needed. When the adhesive composition P contains an active energy ray-curable component, after the adhesive layer is attached to the target member, the adhesive layer is irradiated with active energy rays to harden the adhesive layer, whereby a very excellent durability can be obtained. the adhesive layer.

In addition, the adhesive composition P refers to a mixture of various components remaining in the adhesive layer in the original state or in a reacted state, and components removed in the drying process, such as the polymerization solvent and diluting solvent described later, are not included in the adhesive In sexual composition P.

(5) Manufacture of adhesive composition

The adhesive composition P can be prepared by producing the (meth)acrylate polymer (A) and mixing the obtained (meth)acrylate polymer (A), the silane coupling agent (B) having a mercapto group, and according to the Manufactured by adding a crosslinking agent (C) and additives.

The (meth)acrylate polymer (A) can be formed by The mixture of the monomer units of the compound is produced by polymerizing by a normal radical polymerization method. The polymerization of the (meth)acrylate polymer (A) can be performed by a solution polymerization method or the like using a polymerization initiator as necessary. As a polymerization solvent, ethyl acetate, n-butyl acetate, isobutyl acetate, toluene, acetone, hexane, methyl ethyl ketone, etc. are mentioned, for example, You may use 2 or more types together.

As a polymerization initiator, an azo compound, an organic peroxide, etc. are mentioned, You may use 2 or more types together. Examples of the azo compound include 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 1,1'-azobis(cyclohexane Alkane 1-carbonitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethyl-4-methoxypentane) 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], etc.

Examples of organic peroxides include benzyl peroxide, tert-butyl peroxybenzoate, cumene hydroperoxide, diisopropyl peroxydicarbonate, di-n-propyl peroxydicarbonate, di-n-propyl peroxydicarbonate, (2-ethoxyethyl) peroxydicarbonate, tert-butyl peroxyneodecanoate, tert-butyl peroxypivalate, (3,5,5-trimethylhexanol) peroxide, Dipropylene peroxide, diacetyl peroxide, etc.

In addition, in the above-mentioned 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 a (meth)acrylate polymer (A) is obtained, a silane coupling agent (B) having a mercapto group and, if necessary, a crosslinking agent (C) are added to the solution of the (meth)acrylate polymer (A). , additives and diluting solvent are mixed thoroughly, thereby obtaining the adhesive composition P (coating solution) diluted with solvent.

As the above-mentioned diluting solvent, for example, hexane, heptane, cyclohexane are used. Aliphatic hydrocarbons such as alkane, aromatic hydrocarbons such as toluene and xylene, halogenated hydrocarbons such as dichloromethane and dichloroethane, alcohols such as methanol, ethanol, propanol, butanol, and 1-methoxy-2-propanol , acetone, methyl ethyl ketone, 2-pentanone, isophorone, ketones such as cyclohexanone, ethyl acetate, esters such as butyl acetate, cellosolve solvents such as ethyl cellosolve, etc.

The concentration and viscosity of the thus-prepared coating solution are not particularly limited as long as they are within the range that can be coated, and can be appropriately selected according to the situation. For example, the concentration of the adhesive composition P is diluted to be 10 to 40 mass %. In addition, when obtaining a coating solution, the addition of a diluent solvent or the like is not an essential condition, and the diluent solvent may not be added as long as the adhesive composition P has a coating viscosity or the like. At this time, the adhesive composition P becomes a coating solution using the polymerization solvent of the (meth)acrylate polymer (A) as a dilution solvent as it is.

(6) Manufacture of adhesive

An adhesive can be obtained by heat-processing the said adhesive composition P. The drying process at the time of volatilizing the diluent solvent etc. of the adhesive composition P may also serve as this heat process.

When heat treatment is performed, the heating temperature is preferably 50 to 150°C, and particularly preferably 70 to 120°C. In addition, the heating time is preferably 30 seconds to 10 minutes, and particularly preferably 50 seconds to 2 minutes. After the heat treatment, if necessary, an aging period of about 1 to 2 weeks at normal temperature (for example, 23° C., 50% RH) can be provided. 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 obtained from the adhesive composition P is preferably 30% or more, particularly preferably 40% or more, and even more preferably 50% or more. If the lower limit value of the gel fraction of the adhesive is the above-mentioned or more, the internal The cohesion becomes high, and it becomes the one with excellent step followability under high temperature and high humidity conditions. Further, the upper limit of the gel fraction is preferably 90% or less, particularly preferably 85% or less, and even more preferably 80% or less. If 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 adhesive is excellent in step followability at the time of sticking. Here, the measurement method of the gel fraction of the adhesive is shown in the test example described later.

The adhesive of this embodiment contains a silane coupling agent having a mercapto group as a migration inhibitor, so that it can be attached to, for example, a metal electrode made of copper, silver, etc., a transparent conductive material made of tin-doped indium oxide (ITO), etc. Films, metal nanowire films, wire grid polarizing films and other target components can also effectively suppress migration in the target components. In particular, even when the target member is a metal electrode of a touch panel using copper or silver, which has a higher ionization tendency than metal oxides such as ITO, it is possible to prevent the touch panel caused by disconnection and short circuit of the electrodes. bad drive.

[Adhesive Sheet]

As shown in FIG. 1, the adhesive sheet 1 of the present embodiment is composed of two release sheets 12a, 12b; The adhesive layer 11 sandwiched by 12a, 12b. However, in the adhesive sheet 1, the peeling sheets 12a and 12b are not necessarily constituting elements, and are peeled off and removed when the adhesive sheet 1 is used. In addition, the peeling surface of a peeling sheet in this specification means the surface which has peeling property in a peeling sheet, and includes both the surface which performed peeling process, and the surface which shows peeling property even without performing peeling process.

(1) Adhesive layer

The adhesive layer 11 is composed of the aforementioned adhesive. The lower limit of the thickness of the adhesive layer 11 (value measured in accordance with JIS K7130) is preferably 10 μm or more, and is preferably 25 μm The above is particularly preferable, and 50 μm or more is further preferable. By setting the lower limit of the thickness of the adhesive layer 11 to be more than the above, it is possible to sufficiently exhibit an excellent adhesive force. Further, the upper limit of the thickness of the adhesive layer 11 is preferably 300 μm or less, particularly preferably 250 μm or less, and even more preferably 100 μm or less. When the upper limit value of the thickness of the adhesive layer 11 is the above-mentioned or less, workability becomes favorable. In addition, the adhesive layer 11 may be formed as a single layer, or may be formed by laminating a plurality of layers.

(2) Peel-off sheet

It does not specifically limit as a release sheet 12a, 12b, A well-known plastic film can be used. For example, polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film can be used , polyethylene naphthalate film, polybutylene terephthalate film, polyurethane film, ethylene vinyl acetate film, ionomer resin film, ethylene ‧(meth)acrylic copolymer film, ethylene ‧(methyl) base) acrylate copolymer film, polystyrene film, polycarbonate film, polyimide film, fluororesin film, etc. In addition, these crosslinked films can also be used. In addition, these laminated films may be used.

It is preferable that the peeling process is performed on the peeling surface (especially the surface contacting the adhesive layer 11) of the said peeling sheet 12a, 12b. Examples of the release agent used for the release treatment include alkyd-based, silicone-based, fluorine-based, unsaturated polyester-based, polyolefin-based, and wax-based release agents. In the release sheets 12a and 12b, it is preferable that one release sheet is a heavy release type release sheet with a large release force, and the other release sheet is a light release type release sheet with a smaller release force.

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

(3) Manufacture of adhesive sheet

As an example of the production of the adhesive sheet 1, the coating liquid of the adhesive composition P is applied to the release surface of one release sheet 12a (or 12b), and the adhesive composition P is subjected to heat treatment to crosslink the adhesive composition P to form a coating layer. , and the peeling surface of another peeling sheet 12b (or 12a) is superimposed on the coating layer. When the aging period is required, the coating layer becomes the adhesive layer 11 by passing the aging period, and the coating layer directly becomes the adhesive layer 11 when the aging period is not required. Thereby, the said adhesive sheet 1 was obtained. The heat treatment and aging conditions are as described above.

As another example of the production of the adhesive sheet 1, the above-mentioned coating liquid of the adhesive composition P is applied to the release surface of one release sheet 12a, and the adhesive composition P is cross-linked by heat treatment to form a coating layer, thereby obtaining a tape. The release sheet 12a of the coating layer. Then, the above-mentioned coating liquid of the adhesive composition P is applied to the release surface of the other release sheet 12b, and heat treatment is performed to crosslink the adhesive composition P to form a coating layer, thereby obtaining a release sheet 12b with a coating layer. And, the release sheet 12a with a coating layer and the release sheet 12b with a coating layer are bonded together so that the two coating layers are in contact with each other. When the curing period is required, the above-mentioned coating layer of the laminated layer becomes the adhesive layer 11 by passing the curing period, and when the curing period is not required, the above-mentioned coating layer of the laminated layer directly becomes the adhesive layer 11 . Thereby, the said adhesive sheet 1 was obtained. According to this manufacturing example, even when the adhesive layer 11 is thick, it can be manufactured stably.

As a method for applying the coating liquid of the above-mentioned adhesive composition P, for example, a bar coating method, a blade coating method, a roll coating method, a blade coating method, a die coating method, a gravure coating method, etc. can be used. .

(4) Adhesion

The lower limit of the adhesive force of the adhesive sheet 1 of the present embodiment to soda lime glass is preferably 5N/25mm or more, particularly preferably 8N/25mm or more, and even more preferably 10N/25mm or more. If the lower limit value of the adhesive force of the adhesive sheet 1 is more than the above, it will be excellent in step followability under high temperature and high humidity conditions. On the other hand, the upper limit of the above-mentioned adhesive force is not particularly limited. Considering the ease of peeling off the release sheets 12a and 12b from the adhesive layer 11 during use, it is preferably 50N/25mm or less, and 30N/25mm or less. Especially good. In addition, considering the reworkability, 26N/25mm or less is preferable. In this case, even if misbonding occurs, the member can be easily reused.

The adhesive force in this specification basically refers to the adhesive force measured by the 180-degree peeling method according to JIS Z0237:2009. The measurement sample is set to be 25 mm in width and 100 mm in length, and the measurement sample is attached to the adherend. After being pressurized at 0.5 MPa and 50°C for 20 minutes, it was left to stand for 24 hours under the conditions of normal pressure, 23°C, and 50% RH, and then measured at a peeling speed of 300 mm/min.

(5) Use of adhesive sheet

By using the above-mentioned adhesive sheet 1, for example, the capacitive touch panel 2 shown in FIG. 2 can be manufactured. The touch panel 2 includes a display module 3, a first thin film sensor 5a laminated thereon through an adhesive layer 4, a second thin film sensor 5b laminated thereon through an adhesive layer 11, and It is constituted by laminating the cover material 6 through the adhesive layer 11 on the top.

The adhesive layer 11 in the above-mentioned touch panel 2 is the adhesive layer 11 of the above-mentioned adhesive sheet 1 .

Examples of the display module 3 include a liquid crystal (LCD) module, a light emitting diode (LED) module, and an organic electroluminescence (organic EL) module. group, electronic paper, etc.

The adhesive layer 4 may be formed by the adhesive layer 11 of the above-mentioned adhesive sheet 1, or may be formed by other adhesives or adhesive sheets. In the latter case, examples of the adhesive constituting the adhesive layer 4 include acrylic adhesives, rubber-based adhesives, silicone-based adhesives, urethane-based adhesives, polyester-based Vinyl ether-based adhesives, etc. Among them, acrylic-based adhesives are preferred.

The first thin film sensor 5 a and the second thin film sensor 5 b in this embodiment include a base film 51 and electrodes 52 formed on the base film 51 , respectively. 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 composed of copper, silver, etc., and a patterned transparent conductive film composed of tin-doped indium oxide (ITO) or the like.

The electrodes 52 of the first thin film sensor 5a and the electrodes 52 of the second thin film sensor 5b generally constitute one of the circuit patterns in the X-axis direction, and the other constitutes the 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 on the upper side of the first thin film sensor 5a in FIG. 2 , but it is not limited to this, and may be located on the lower side of the first thin film sensor 5a .

The cover material 6 is usually mainly composed of a glass plate or a plastic plate. The glass plate is not particularly limited, and examples thereof include chemically strengthened glass, alkali-free glass, quartz glass, soda lime glass, barium/strontium-containing glass, aluminosilicate glass, lead glass, borosilicate glass, and barium borosilicate glass. Acid glass, etc. There is no particular limitation as a plastic board For example, an acrylic plate, a polycarbonate plate, etc. which consist of polymethyl methacrylate etc. are mentioned.

In addition, functional layers such as a hard coat layer, an antireflection layer, and an antiglare layer may be provided on one or both surfaces of the glass plate or plastic plate, and optical members such as a hard coat film, an antireflection film, and an antiglare film may be laminated.

In the present embodiment, the surface of the cover material 6 on the adhesive layer 11 side has a level difference, specifically, a level difference formed by the presence or absence of the printed layer 7 . The printing layer 7 is generally formed in a frame shape on the adhesive layer 11 side of the cover material 6 .

The material constituting the printed layer 7 is not particularly limited, and known materials for printing can be used. The thickness of the printed layer 7, that is, the lower limit of the height of the step is preferably 3 μm or more, more preferably 5 μm or more, and particularly preferably 7 μm or more. In addition, the upper limit is preferably 50 μm or less, more preferably 25 μm or less, and particularly preferably 15 μm or less.

Hereinafter, an example of the manufacturing method of the said touch panel 2 is demonstrated.

As the adhesive sheet 1, a first adhesive sheet 1 and a second adhesive sheet 1 were prepared. One peeling sheet 12a is peeled off from the first adhesive sheet 1, and the exposed adhesive layer 11 (first adhesive layer 11) is brought into contact with the second thin film sensor 5b so as to be in contact with the electrode 52 of the second thin film sensor 5b. The tester 5b is fitted. Then, one peeling sheet 12a is peeled off from the second adhesive sheet 1, and the exposed adhesive layer 11 (second adhesive layer) is brought into contact with the first film so as to be in contact with the electrode 52 of the first film sensor 5a The sensor 5a is attached.

Then, the other peeling sheet 12b of the second adhesive sheets is peeled off, and the exposed second adhesive layer 11 is combined with the second thin film sensor 5b. The two are bonded together so that the surface on the opposite side to the side on which the first adhesive layer 11 is laminated (the exposed surface of the base film 51 of the second thin film sensor 5b) is in contact with each other. Thereby, the laminated body which laminated|stacked the peeling sheet 12b, the 1st adhesive bond layer 11, the 2nd thin film sensor 5b, the 2nd adhesive bond layer 11, and the 1st thin film sensor 5a in this order was obtained.

Next, 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). Next, the release sheet 12b is peeled off from the above-mentioned laminate, and the cover material 6 is attached to the exposed first adhesive layer 11 so that the printed layer 7 side of the cover material 6 is in contact with the adhesive layer 11 . In this way, the cover material 6, the first adhesive layer 11, the second thin film sensor 5b, the second adhesive layer 11, the first thin film sensor 5a, the adhesive layer 4 and the release sheet can be laminated in this order. the constituent body.

Finally, the release sheet is peeled off from the above-mentioned structure, and the structure is attached to the display module 3 so that the exposed adhesive layer 4 is in contact with the display module 3 . Thereby, the touch panel 2 shown in FIG. 2 is manufactured.

Even in the case where the above-mentioned touch panel 2 is placed under a high temperature and high humidity condition and a voltage is applied to the electrodes 52 in this state, the adhesive layer 11 in contact with the electrodes 52 contains the migration inhibitor (having a mercapto group) derived from the present embodiment The composition of the silane coupling agent) can effectively inhibit the migration of the electrode 52. Thereby, the drive failure of the touch panel 2 caused by the disconnection and short circuit of the electrode 52 can be prevented.

The embodiments described above are described to facilitate understanding of the present invention, and are not described to limit the present invention. Therefore, each of the requirements disclosed in the above-described embodiments also includes all design changes and equivalents within the technical scope of the present invention.

For example, the release sheets 12a and 12b of the adhesive sheet 1 may be omitted. any of the .

【Example】

Hereinafter, the present invention will be described in more detail by way of examples, but the scope of the present invention is not limited to these examples.

[Example 1]

1. Preparation of (meth)acrylate copolymers

A (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. As a result of measuring the molecular weight of this (meth)acrylate polymer (A) by the method mentioned later, 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 below), 3-mercaptopropyltrimethoxy as the silane coupling agent (B) having a mercapto group Co-condensate of methylsilane and methyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "X-41-1810", oligomer type, mercapto equivalent: 450 g/mol) 0.05 Part by mass, 0.23 part by mass of trimethylolpropane-modified toluene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., product name "Coronate L") as a crosslinking agent (C), mixed and sufficiently stirred, and By diluting with methyl ethyl ketone, a coating solution of the adhesive composition having a solid content concentration of 38% by mass was obtained.

Here, Table 1 shows each blending (solid content conversion value) of the adhesive composition when the (meth)acrylate polymer (A) is 100 parts by mass (solid content conversion value). In addition, the details of the abbreviations etc. described in Table 1 are as follows.

[(Meth)acrylate polymer (A)]

2EHA: 2-ethylhexyl acrylate

MMA: methyl methacrylate

HEA: 2-hydroxyethyl acrylate

[Silane coupling agent (B) having mercapto group]

X-41-1810: Cocondensate of 3-mercaptopropyltrimethoxysilane and methyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "X-41-1810", oligo Polymer type, thiol equivalent: 450g/mol)

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

[Other silane coupling agents]

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

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

3. Manufacture of adhesive sheet

Peeling treatment of a heavy release type release sheet (manufactured by LINTEC Corporation, trade name "SP-PET382150", thickness: 38 μm) obtained by peeling one side of a polyethylene terephthalate film with a silicone-based release agent On the surface, the coating solution of the adhesive composition obtained in the above-mentioned process 2 was coated with a knife coater, and then heat-treated at 90° C. for 1 minute to form a coating layer (thickness: 25 μm). Similarly, a light release type release sheet obtained by peeling one side of a polyethylene terephthalate film with a silicone-based release agent (Product name "SP-PET382120", manufactured by LINTEC Corporation), the coating solution of the adhesive composition obtained in the above-mentioned process 2 was applied with a knife coater, and then heat-treated at 90°C A coating layer (thickness: 25 μm) was formed in 1 minute.

Next, the heavy release type release sheet with a coating layer obtained in the above and the light release type release sheet with a coating layer obtained in the above are pasted in such a way that the two coating layers are in contact with each other, and the It aged for 7 days under the conditions of 23 degreeC, 50%RH, and produced the adhesive sheet which consists of a heavy release type release sheet/adhesive layer (thickness: 50 micrometers)/light release type release sheet.

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

The same procedure as in Example 1 was carried out, except that the types and ratios of the silane coupling agents (the silane coupling agent having a mercapto group (B) and other silane coupling agents) and the ratio of the crosslinking agent (C) were changed as shown in Table 1. Manufacture of adhesive sheets. In addition, for Comparative Examples 7 to 10, N,N-bis(2-ethylhexyl)-(4 or 5)-methyl-1H-benzotriazole-1-methylamine (manufactured by BASF, trade name "IRGMET 39") was blended into the adhesive composition as a rust inhibitor at the ratio shown in Table 1.

Here, the above-mentioned weight average molecular weight (Mw) is the weight average molecular weight in terms of polystyrene measured (GPC measurement) using gel permeation chromatography (GPC) under the following conditions.

<Measurement conditions>

‧GPC measurement device: 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

‧Measurement solvent: tetrahydrofuran

‧Measurement temperature: 40℃

[Test Example 1] (Measurement of gel fraction)

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

Next, at room temperature (23° C.), the adhesive wrapped in the above polyester mesh was immersed in ethyl acetate for 24 hours. Then, the adhesive was taken out, air-dried for 24 hours in an environment with a temperature of 23° C. and a relative humidity of 50%, and also dried in an oven at 80° C. for 12 hours. After drying, the mass of the adhesive itself is calculated by taking its mass with a precision balance and subtracting the mass of the above-mentioned net alone. Let the mass at this time be 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 Examples and Comparative Examples, and the exposed adhesive layer was attached to a polyethylene terephthalate (PET) film (TOYOBO CO. , LTD., product name "PET A4300", thickness: 100 μm) of the easy-adhesion layer to obtain a heavy-peeling release sheet/adhesive layer/PET film laminate. The obtained laminate was cut into a width of 25 mm and a length of 100 mm, and this was used as a sample.

Under the environment of 23°C and 50%RH, the heavy peeling type release sheet was peeled off from the above sample, and the exposed adhesive layer was attached to soda lime glass (Nippon After that, it was pressurized at 0.5 MPa and 50° C. for 20 minutes in an autoclave made by KURIHARA CORPORATION. Then, after standing for 24 hours under the conditions of 23° C. and 50% RH, using a tensile tester (manufactured by ORIENTEC Co., LTD., Tensilon), the adhesion was measured under the conditions of a peeling speed of 300 mm/min and a peeling angle of 180 degrees. force (N/25mm). Conditions other than those described here 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) Fabrication of wiring board

Copper in a copper-clad laminate (manufactured by NIKKAN INDUSTRIES Co., Ltd., product name "NIKAFLEX") in which copper foil (thickness: 18 μm) and polyethylene terephthalate film (thickness: 50 μm) are laminated On the foil surface, an etching resist pattern was printed by screen printing. After that, unnecessary copper foils are removed by etching to form comb-shaped electrodes. 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 type release sheet was peeled off from the adhesive sheets obtained in Examples and Comparative Examples, and the exposed adhesive layer was attached to a polyethylene terephthalate (PET) film (TOYOBO CO. , LTD., product name "PET A4300", thickness: 100 μm) of the easy-adhesion layer to obtain a heavy-peeling release sheet/adhesive layer/PET film laminate. Next, the heavy release type release sheet was peeled off from the above-mentioned laminated body, and the exposed adhesive layer was attached to the above-mentioned comb-shaped electrode, and this was used as a sample.

The above-mentioned sample was allowed to stand still under humid heat conditions of 85° C. and 85% RH, and a voltage of 5 V was applied between electrodes in this state to perform a migration test. Since the beginning of the test After 8 hours, 24 hours, and 48 hours, the comb-shaped electrodes were observed with an optical microscope (magnification: 10 times), and the effect of preventing migration was evaluated based on the evaluation criteria shown below. The results are shown in Table 2.

⊚: Dissolution of the electrode (positive electrode) and formation of dendrites in the electrode (negative electrode) were not observed at all.

○: Dissolution was observed only at the end of the electrode (positive electrode), and dendrite formation in the electrode (negative electrode) was not observed.

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

In addition, the reference image of the said evaluation criteria is shown in FIG. 3. FIG.

As can be seen from Table 2, the adhesive sheets obtained in the examples can effectively prevent and inhibit migration, and are excellent in the migration prevention effect.

【Industrial Availability】

The anti-migration agent, the adhesive agent, and the adhesive sheet of the present invention can be suitably used for a capacitive touch panel using a copper electrode or a silver electrode, for example.

1‧‧‧Adhesive Sheet

11‧‧‧Adhesive layer

12a, 12b‧‧‧Peeling sheet

Claims (3)

An adhesive sheet comprising one or two release sheets and an adhesive layer provided in contact with the release surface of the release sheet, wherein the adhesive layer is polymerized with a (meth)acrylate (A); and an acrylic adhesive obtained as an adhesive composition of a mercapto group-containing silane coupling agent (B) as a migration inhibitor, and the (meth)acrylate polymer (A) contains 10% by mass More than 35 mass % or less of hydroxyl-containing monomers are used as monomer units constituting the polymer, the adhesive force of the adhesive sheet to soda lime glass is 5 N/25 mm or more and 50 N/25 mm or less, and the adhesive layer is used in the touch panel. The above is arranged so as to be in contact with the electrodes. The adhesive sheet according to claim 1, wherein the adhesive composition further contains a crosslinking agent (C). The adhesive sheet according to claim 1, wherein the content of the mercapto group-containing silane coupling agent (B) in the adhesive composition is 100 relative to the (meth)acrylate polymer (A) 100 The mass part is 0.01 mass part or more and 5 mass parts or less.

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