KR102350144B1 - Adhesive composition, adhesive, adhesive sheet and display element - Google Patents

Abstract

It is an adhesive composition which forms the adhesive for bonding together the 1st display body structural member which has a level|step difference in the surface on the side to be bonded at least, and a 2nd display body structural member, Comprising: 1st display body structural member and/or 2nd display body structural member The member has an electrode on the surface on the side to be bonded at least, The said adhesive composition contains a (meth)acrylic acid ester polymer (A) and the silane coupling agent (B) which has a mercapto group. The adhesive composition. According to the adhesive obtained from such an adhesive composition, the migration in the said electrode can be prevented and suppressed effectively.

Description

Adhesive composition, adhesive, adhesive sheet, and display {ADHESIVE COMPOSITION, ADHESIVE, ADHESIVE SHEET AND DISPLAY ELEMENT}

TECHNICAL FIELD This invention relates to the adhesive composition which can be used for display bodies, such as a touch panel, an adhesive, and an adhesive sheet, and the display body using them.

DESCRIPTION OF RELATED ART In various mobile electronic devices, such as a smart phone and a tablet terminal in recent years, the case where a touch panel is used as a display is increasing. As a touch panel method, there are a resistive film method, a capacitive method, and the like, but in the above mobile electronic devices, the capacitive method is mainly employed.

In recent years, enlargement of a touch panel is attained, and a mesh-shaped metal electrode, for example, a copper electrode, or a silver electrode is examined as such an electrode material for 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 is melted and disconnected, or in the negative electrode, dendrites are formed by precipitation of the positive electrode component and a short circuit occurs.

This migration is particularly likely to occur when a voltage is applied to the electrode under high temperature and high humidity. When such migration occurs, the touch panel is not driven normally. In particular, in recent years when miniaturization and narrowing of the pitch of the electrode are progressing, disconnection and short circuit of the electrode due to migration are likely to occur.

By the way, in patent document 1, the adhesive composition for touch panels containing a benzotriazole compound as a rust preventive agent is disclosed.

Japanese Patent Application Laid-Open No. 2014-177611

However, even if the benzotriazole compound as a rust preventive agent had the corrosion prevention effect of metal wiring, it was not able to fully prevent and suppress migration.

This invention was made in view of the above actual conditions, and an object of this invention is to provide the adhesive composition which can effectively prevent and suppress migration, an adhesive, an adhesive sheet, and a display body.

In order to achieve the said object, first, this invention forms the adhesive for bonding together the 1st display body structural member and 2nd display body structural member which have a level|step difference in the surface on the side bonded at least first. As a composition, a said 1st display body structural member and/or a said 2nd display body structural member has an electrode in the surface by which it is bonded at least, and the said adhesive composition is a (meth)acrylic acid ester polymer (A) and mer The silane coupling agent (B) which has a capto group is contained, The adhesive composition characterized by the above-mentioned is provided (Invention 1).

According to the pressure-sensitive adhesive obtained from the pressure-sensitive adhesive composition according to the invention (invention 1), in particular, the first display body structural member and/or the second display that the pressure-sensitive adhesive comes into contact with by the action of the silane coupling agent (B) having a mercapto group. Migration in the electrode of a sieve structural member can be effectively prevented and suppressed.

In the said invention (invention 1), it is preferable that the said silane coupling agent (B) which has a mercapto group is a mercapto-group containing oligomer type silane coupling agent (invention 2).

In the above inventions (Inventions 1 and 2), it is preferable that the mercapto group equivalent of the organosilicon compound constituting the silane coupling agent (B) having a mercapto group is 100 g/mol or more and 1000 g/mol or less. (Invention 3).

In the said invention (Inventions 1-3), content of the silane coupling agent (B) which has the said mercapto group in the said adhesive composition is 0.01 with respect to 100 mass parts of said (meth)acrylic acid ester polymers (A). It is preferable that it is 5 mass parts or more and 5 mass parts or less (Invention 4).

In the above inventions (Inventions 1 to 4), the (meth)acrylic acid ester polymer (A) preferably 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 said invention (Inventions 1-5), it is preferable that the said adhesive composition further contains a crosslinking agent (C) (Invention 6).

Second, the present invention provides a pressure-sensitive adhesive obtained by crosslinking the pressure-sensitive adhesive composition (Inventions 1 to 6) (Invention 7).

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

In the invention (invention 8), the pressure-sensitive adhesive sheet includes two release sheets, and the pressure-sensitive adhesive layer is sandwiched by the release sheet so as to be in contact with the release surfaces of the two release sheets. preferred (invention 9).

Fourth, this invention sticks together the 1st display body structural member which has a level|step difference in the surface on the side joined at least, the 2nd display body structural member, the said 1st display body structural member, and the said 2nd display body structural member It is a display body provided with the adhesive layer to combine, The said 1st display body structural member and/or the said 2nd display body structural member has an electrode in the surface by which it is bonded at least, The said adhesive layer has the said adhesive sheet (Invention 8) , 9) provides a display body characterized in that the pressure-sensitive adhesive layer (Invention 10).

ADVANTAGE OF THE INVENTION According to the adhesive composition which concerns on this invention, an adhesive, an adhesive sheet, and a display body, migration can be prevented and suppressed effectively.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing of the adhesive sheet which concerns on one Embodiment of this 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;

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described.

[Adhesive composition]

The adhesive composition (hereinafter, sometimes referred to as "adhesive composition (P)") which concerns on this embodiment is a 1st display body structural member which has a level|step difference in the surface on the side to be bonded at least, and a 2nd display body structural member ( A 1st display body structural member and/or a 2nd display body structural member is an adhesive composition which forms the adhesive for bonding together (which has an electrode in the surface on the side to be bonded at least), Comprising: (meth)acrylic acid ester polymer (A) , contains a silane coupling agent (B) having a mercapto group, and preferably further contains a crosslinking agent (C). In this specification, (meth)acrylic acid ester means both an acrylic acid ester and a methacrylic acid ester. Other similar terms are the same. In addition, the concept of "copolymer" shall also be included in "polymer". In addition, a display body and a display body structural member are mentioned later.

When the adhesive composition (P) which concerns on this embodiment contains the silane coupling agent (B) which has a mercapto group, when the adhesive obtained from an adhesive composition (P) contacts an electrode, it prevents that an electrode melt|dissolves in a positive electrode is suppressed, and formation of dendrites in the negative electrode is prevented and suppressed. That is, migration in an electrode is effectively prevented and suppressed (this effect is called "migration prevention effect" in some cases). Thereby, even when the said adhesive comes into contact with the miniaturized/narrow-pitch electrode, for example, disconnection and short circuit of an electrode are prevented. In particular, when the electrode is an electrode of a touch panel, a malfunction of the touch panel caused by disconnection or short circuit of the electrode is prevented.

Here, as the electrode, for example, a metal electrode made of copper, silver, etc. (including those in the form of a mesh or grid), a transparent conductive film made of tin-doped indium oxide (ITO), etc. (including patterned ones) and the like. Among the electrodes, a metal electrode mainly composed of a non-oxidized metal, specifically, a metal electrode made of copper or silver is preferable. Although the metal which is not oxidized has a higher ionization tendency than metal oxides, such as ITO, according to the adhesive obtained from the adhesive composition (P) which concerns on this embodiment, disconnection and a short circuit of an electrode are effectively prevented also in that case.

In addition, the pressure-sensitive adhesive layer composed of the pressure-sensitive adhesive obtained from the pressure-sensitive adhesive composition (P) containing the silane coupling agent (B) having a mercapto group is a silane coupling agent having a mercapto group ( When the component derived from B) exists, adhesiveness with a display body structural member is high, and it becomes the thing excellent in step|step difference followability|trackability. Specifically, even when the pressure-sensitive adhesive layer is affixed to a display body structural member having a level difference and exposed to high temperature and high humidity conditions for a predetermined period of time (eg, 85°C, 85%RH for 72 hours), bubbles are formed near the level difference , lifting, peeling, etc. are suppressed (it is excellent in followability to steps under high temperature and high humidity conditions). Thereby, generation|occurrence|production of the reflection loss of light in the step vicinity is suppressed, and the image quality of a display body can be maintained favorably.

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

The (meth)acrylic acid ester polymer (A) can express preferable adhesiveness by containing the C1-C20 (meth)acrylic-acid alkylester of an alkyl group as a monomer unit which comprises the said polymer. From such a viewpoint, the (meth)acrylic acid ester polymer (A) preferably contains, as a lower limit, 50% by mass or more of (meth)acrylic acid alkylester having 1 to 20 carbon atoms in the alkyl group as a monomer unit constituting the polymer. And it is preferable to contain especially 60 mass % or more, Furthermore, it is preferable to contain 70 mass % or more. When the said (meth)acrylic-acid alkylester is contained 50 mass % or more, the (meth)acrylic-acid ester polymer (A) can exhibit preferable adhesiveness. In addition, the (meth)acrylic acid ester polymer (A) preferably contains 97 mass% or less as an upper limit of the (meth)acrylic acid alkylester as a monomer unit constituting the polymer, and particularly contains 90 mass% or less It is preferable, and also it is preferable to contain 85 mass % or less. By containing 97 mass % or less of the said (meth)acrylic-acid alkylester, another monomer component can be introduce|transduced in a preferable quantity in (meth)acrylic-acid ester polymer (A).

Examples of the (meth)acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, (meth) Acrylic acid n-pentyl, (meth)acrylic acid n-hexyl, (meth)acrylic acid 2-ethylhexyl, (meth)acrylic acid isooctyl, (meth)acrylic acid n-decyl, (meth)acrylic acid n-dodecyl, (meth)acrylic acid Myristyl, (meth) acrylate palmityl, (meth) acrylate stearyl, (meth) acrylic acid cyclohexyl, (meth) acrylate isobornyl, (meth) acrylate adamantyl, etc. are mentioned, Among them, adhesiveness It is preferable that the C4-C8 (meth)acrylic acid ester of an alkyl group is contained from a viewpoint of improving more. These may be used independently and may be used in combination of 2 or more type. In addition, the alkyl group in the C1-C20 (meth)acrylic-acid alkylester of an alkyl group means a linear, branched or cyclic alkyl group.

Further, as (meth)acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group, the glass transition temperature (Tg) as a homopolymer is higher than 0°C (preferably 70°C or higher), and the glass transition as a homopolymer is a hard monomer. It is also preferable to use a combination of soft monomers having a temperature (Tg) of 0°C or less. This is because, while securing the adhesiveness and flexibility with the soft monomer, the cohesive force is improved with the hard monomer, whereby the level difference followability in a display panel (touch panel) can be made more excellent.

It is preferable that the mass ratio of the said hard monomer and a soft monomer is 5:95-40:60, and it is especially preferable that it is 20:80-30:70.

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 adamantyl acrylate (Tg 115°C) and adamantyl methacrylate (Tg 141°C). These may be used independently and may be used in combination of 2 or more type.

Among the hard monomers, methyl acrylate, methyl methacrylate, and isobornyl acrylate are preferable from the viewpoint of further exhibiting the performance of the hard monomer while preventing adverse effects on other properties such as tackiness and transparency. When adhesiveness is also considered, methyl acrylate and methyl methacrylate are more preferable, and methyl methacrylate is especially preferable.

As said soft monomer, the acrylic acid alkylester 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 independently and may be used in combination of 2 or more type.

The (meth)acrylic acid ester polymer (A) preferably contains a reactive functional group-containing monomer as a monomer unit constituting the polymer. The reactive functional group derived from this reactive functional group containing monomer reacts with the crosslinking agent (C) mentioned later, by this, a crosslinked structure (three-dimensional network structure) is formed, and the adhesive which has a desired cohesive force is obtained.

Examples of the reactive functional group-containing monomer that the (meth)acrylic acid ester polymer (A) contains as a monomer unit constituting the polymer include a monomer having a hydroxyl group in the molecule (hydroxyl group-containing monomer), a monomer having a carboxyl group in the molecule (carboxyl group-containing monomer) ), a monomer having an amino group in the molecule (amino group-containing monomer), and the like are preferably mentioned. Among these, a hydroxyl-containing monomer which is excellent in the reactivity with a crosslinking agent (C) and moist-heat-resistance whitening property, and has few adverse effects on an electrode is especially preferable.

As a hydroxyl-containing monomer, For example, (meth)acrylic acid 2-hydroxyethyl, (meth)acrylic acid 2-hydroxypropyl, (meth)acrylic acid 3-hydroxypropyl, (meth)acrylic acid 2-hydroxybutyl; (meth)acrylic acid hydroxyalkyl esters, such as (meth)acrylic-acid 3-hydroxybutyl and (meth)acrylic-acid 4-hydroxybutyl, etc. are mentioned. Especially, from the point of the reactivity of the hydroxyl group in the (meth)acrylic acid ester polymer (A) obtained with the crosslinking agent (C), and copolymerizability with other monomers, 2-hydroxyethyl (meth)acrylate or 4-(meth)acrylic acid Hydroxybutyl is preferred. These may be used independently and may be used in combination of 2 or more type.

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 of the carboxyl group in the obtained (meth)acrylic acid ester polymer (A) with the crosslinking agent (C) and copolymerizability with other monomers. These may be used independently and may be used in combination of 2 or more type.

As an amino-group containing monomer, (meth)acrylic-acid aminoethyl, (meth)acrylic-acid n-butylaminoethyl, etc. are mentioned, for example. These may be used independently and may be used in combination of 2 or more type.

The (meth)acrylic acid ester polymer (A) preferably contains, as a lower limit, 3% by mass or more of a hydroxyl group-containing monomer as a monomer unit constituting the polymer, particularly preferably 10% by mass or more, and further It is preferable to contain 15 mass % or more. Further, the (meth)acrylic acid ester polymer (A) preferably contains, as an upper limit, 35 mass% or less of a hydroxyl group-containing monomer as a monomer unit constituting the polymer, and particularly preferably contains 30 mass% or less, Furthermore, it is preferable to contain 25 mass % or less. When a (meth)acrylic acid ester polymer (A) contains a hydroxyl-containing monomer in said quantity as a monomer unit, a predetermined amount of hydroxyl groups will remain in the adhesive obtained. The hydroxyl group is a hydrophilic group, and when such a hydrophilic group is present in a predetermined amount of the pressure-sensitive adhesive, even when the pressure-sensitive adhesive is placed under high temperature and high humidity conditions, compatibility with moisture that has penetrated into the pressure sensitive adhesive is good under the high temperature and high humidity conditions, and as a result, it becomes normal temperature and humidity. Whitening of the adhesive at the time of turning will be suppressed (it is excellent in moist-heat-resistance whitening property).

As for the degree of whitening suppression, it is preferable that the haze value (value measured according to JISK7136:2000) of the adhesive layer at the time of returning to normal temperature and normal humidity after implementing high-temperature, high-humidity conditions is 1.0 % or less, and especially 0.9 % or less It is preferable, and furthermore, it is preferable that it is 0.8 % or less. Moreover, it is preferable that an adhesive layer has the haze value as mentioned above even when it is in a state. Transparency is very high that a haze value is 1.0 % or less, and it becomes a thing suitable as an optical use.

However, as mentioned above, when a hydrophilic group exists in a predetermined amount of an adhesive, an adhesive will become easy to contain water, and migration will become easy to generate|occur|produce in the electrode which contacts the said adhesive. However, by containing the silane coupling agent (B) which has a mercapto group, the adhesive composition (P) which concerns on this embodiment can prevent and suppress effectively that migration generate|occur|produces in the electrode which contacts.

Although it is preferable that the (meth)acrylic acid ester polymer (A) does not contain a carboxyl group-containing monomer as a monomer unit which comprises the said polymer, it is permissible to contain a predetermined amount. Since a carboxyl group is an acid component, although migration of a target member is usually concerned, the adhesive which concerns on this embodiment is obtained from the adhesive composition (P) containing the silane coupling agent (B) which has a mercapto group, and a carboxyl group This is because even if there exists a migration prevention effect. Specifically, in (meth)acrylic acid ester polymer (A), as a monomer unit, it is 5 mass % or less of a carboxyl group-containing monomer, Preferably it is permissible to contain in the quantity of 2 mass % or less.

The (meth)acrylic acid ester polymer (A) may contain other monomers as a monomer unit constituting the polymer as desired. As another monomer, in order not to interfere with the action of a reactive functional group containing monomer, the monomer which does not contain the functional group which has reactivity is preferable. Examples of such other monomers include (meth)acrylic acid alkoxyalkyl esters such as (meth)acrylic acid methoxyethyl and (meth)acrylic acid ethoxyethyl, (meth)acrylic acid N,N-dimethylaminoethyl, (meth)acrylate (meth)acrylic acid ester having a non-crosslinkable tertiary amino group such as N,N-dimethylaminopropyl acrylic acid and (meth)acryloylmorpholine, (meth)acrylamide, dimethylacrylamide, vinyl acetate, styrene, etc. can These may be used independently and may be used in combination of 2 or more type.

A random copolymer may be sufficient as the polymerization aspect of a (meth)acrylic acid ester polymer (A), and a block copolymer may be sufficient as it.

It is preferable that it is 200,000 or more, and, as for the lower limit of the weight average molecular weight of a (meth)acrylic acid ester polymer (A), it is especially preferable that it is 300,000 or more, Furthermore, it is preferable that it is 400,000 or more. If the lower limit of the weight average molecular weight of a (meth)acrylic acid ester polymer (A) is the said or more, an adhesive will become the thing excellent in the level|step difference followable|trackability on high-temperature, high-humidity conditions. In addition, the weight average molecular weight in this specification is the value of standard polystyrene conversion measured by the gel permeation chromatography (GPC) method.

Moreover, it is preferable that it is 1 million or less, and, as for the upper limit of the weight average molecular weight of a (meth)acrylic acid ester polymer (A), it is especially preferable that it is 900,000 or less, Furthermore, it is preferable that it is 700,000 or less. If the upper limit of the weight average molecular weight of a (meth)acrylic acid ester polymer (A) is the said or less, it will be excellent in the step|step difference followable|trackability at the time of an adhesive sticking.

In addition, in an adhesive composition (P), a (meth)acrylic acid ester polymer (A) may be used individually by 1 type, and may be used in combination of 2 or more type.

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

The silane coupling agent (B) which has a mercapto group is comprised from the organosilicon compound which has at least 1 mercapto group and at least 1 alkoxysilyl group in a molecule|numerator. When the use of the adhesive obtained is considered, it is preferable that the silane coupling agent (B) which has a mercapto group has light transmittance, for example, a substantially transparent thing.

Specific examples of the silane coupling agent (B) having a mercapto group include mercaps such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, and 3-mercaptopropyldimethoxymethylsilane. Earthenware-containing low molecular weight silane coupling agent; Mercapto group-containing silane compounds such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, and 3-mercaptopropyldimethoxymethylsilane, and methyltriethoxysilane and ethyltriethoxysilane and mercapto group-containing oligomeric silane coupling agents such as cocondensates of alkyl group-containing silane compounds such as methyltrimethoxysilane and ethyltrimethoxysilane. Among them, a mercapto group-containing oligomer-type silane coupling agent that is more excellent in the migration prevention effect and has good workability is preferable, and a cocondensate of a mercapto group-containing silane compound and an alkyl group-containing silane compound is particularly preferable, and further 3 - A cocondensate of mercaptopropyltrimethoxysilane and methyltriethoxysilane is preferred. These may be used individually by 1 type, and may be used in combination of 2 or more type.

The lower limit of the mercapto group equivalent of the organosilicon compound constituting the silane coupling agent (B) having a mercapto group is preferably 100 g/mol or more, particularly preferably 120 g/mol or more, and further 150 g/mol or more. It is preferably more than moles. By setting the lower limit as described above, the polarity difference with the (meth)acrylic acid ester polymer (A) can be within an appropriate range, and the dispersibility of the silane coupling agent (B) in the pressure-sensitive adhesive can be made preferable.

The upper limit of the mercapto group equivalent of the organosilicon compound constituting the silane coupling agent (B) having a mercapto group is preferably 1000 g/mol or less, particularly preferably 800 g/mol or less, and further 500 g/mol It is preferably less than or equal to moles. By setting the upper limit as described above, deterioration of the optical properties due to phase separation with the (meth)acrylic acid ester polymer (A) can be prevented.

It is preferable that content of the silane coupling agent (B) which has a mercapto group in an adhesive composition (P) is 0.01 mass part or more as a lower limit with respect to 100 mass parts of (meth)acrylic acid ester polymer (A), especially 0.05 It is preferable that it is mass part or more, Furthermore, it is preferable that it is 0.1 mass part or more. Moreover, as an upper limit, it is preferable that it is 5 mass parts or less, It is especially preferable that it is 1.5 mass parts or less, Furthermore, it is preferable that it is 1.0 mass parts or less. When content of the silane coupling agent (B) which has a mercapto group exists in the said range, the migration prevention effect becomes more excellent.

Moreover, it is preferable that the lower limit of the number of moles (mercapto group amount) of mercapto groups in the silane coupling agent (B) per 100 g of (meth)acrylic acid ester polymer (A) is 0.01 mmol or more, and it is especially 0.1 mmol or more It is preferable, and furthermore, it is preferable that it is 0.2 mmol or more. Moreover, it is preferable that it is 30 mmol or less, and, as for the upper limit of the said number of moles, it is especially preferable that it is 5 mmol or less, Furthermore, it is preferable that it is 1.5 mmol or less. When the number of moles of the mercapto group of the silane coupling agent (B) with respect to the (meth)acrylic acid ester polymer (A) is in the above range, the migration prevention effect can be made more excellent.

(3) crosslinking agent (C)

It is preferable that the adhesive composition (P) contains a crosslinking agent (C). The pressure-sensitive adhesive composition (P), by containing the crosslinking agent (C), crosslinks the (meth)acrylic acid ester polymer (A) to form a three-dimensional network structure, improves the cohesive force of the obtained pressure-sensitive adhesive, and improves followability to steps under high-temperature, high-humidity conditions can be further improved.

The crosslinking agent (C) may be one that reacts with the reactive group of the (meth)acrylic acid ester polymer (A), for example, an isocyanate-based crosslinking agent, an epoxy-based crosslinking agent, an amine-based crosslinking agent, a melamine-based crosslinking agent, an aziridine-based crosslinking agent, and a hydrazine-based crosslinking agent. A crosslinking agent, an aldehyde type crosslinking agent, an oxazoline type crosslinking agent, a metal alkoxide type crosslinking agent, a metal chelate type crosslinking agent, a metal salt type crosslinking agent, an ammonium salt type crosslinking agent, etc. are mentioned. When the (meth)acrylic acid ester 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 excellent in reactivity with the hydroxyl group. In addition, a crosslinking agent (C) can be used individually by 1 type or in combination of 2 or more type.

An isocyanate type crosslinking agent contains a polyisocyanate compound at least. As a polyisocyanate compound, For example, aromatic polyisocyanate, such as tolylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, aliphatic polyisocyanate, such as hexamethylene diisocyanate, isophorone diisocyanate, hydrogenated diphenylmethane Alicyclic polyisocyanates, such as diisocyanate, and their biuret forms, isocyanurate forms, furthermore, ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, and a reaction product with a low molecular weight active hydrogen-containing compound such as castor oil An adduct body etc. are mentioned. Among them, trimethylolpropane-modified aromatic polyisocyanate, particularly trimethylolpropane-modified tolylene diisocyanate, is preferable from the viewpoint of reactivity with a hydroxyl group.

The content of the crosslinking agent (C) in the pressure-sensitive adhesive composition (P) is preferably 0.001 parts by mass or more as a lower limit with respect to 100 parts by mass of the (meth)acrylic acid ester polymer (A), and particularly preferably 0.01 parts by mass or more, Furthermore, it is preferable that it is 0.02 mass part or more. Moreover, as an upper limit, it is preferable that it is 10 mass parts or less, It is especially preferable that it is 5 mass parts or less, Furthermore, it is preferable that it is 1 mass part or less.

When content of a crosslinking agent (C) exists in the said range, the cohesive force of the adhesive obtained becomes a preferable thing, and the step|step difference followable|trackability of an adhesive, especially the step|step difference followable|trackability under high-temperature, high-humidity conditions improves more.

(4) Various additives

To the pressure-sensitive adhesive composition (P), if desired, various additives commonly used in acrylic pressure-sensitive adhesives, such as antistatic agents, tackifiers, antioxidants, ultraviolet absorbers, light stabilizers, softeners, fillers, refractive index modifiers, etc. can be added. have. Moreover, you may add another silane coupling agent together separately from the silane coupling agent (B) which has the above-mentioned mercapto group. However, since a rust preventive agent, especially a benzotriazole type rust preventive agent, has an effect|action which inhibits crosslinking of an adhesive composition (P), it is preferable not to add.

In addition, the pressure-sensitive adhesive composition (P) represents a mixture of various components remaining in the pressure-sensitive adhesive layer as it is or in a reacted state, and is a component removed by a drying step or the like, for example, a polymerization solvent or dilution solvent described later. is not contained in the pressure-sensitive adhesive composition (P).

(5) Preparation of adhesive composition

While the adhesive composition (P) mixes the (meth)acrylic acid ester polymer (A) obtained by manufacturing the (meth)acrylic acid ester polymer (A), and the silane coupling agent (B) which has a mercapto group, desired Accordingly, it can be prepared by adding a crosslinking agent (C) and an additive.

A (meth)acrylic acid ester polymer (A) can be manufactured by superposing|polymerizing the mixture of the monomer unit which comprises a polymer by a normal radical polymerization method. Superposition|polymerization of a (meth)acrylic acid ester polymer (A) can be performed by the solution polymerization method etc. using a polymerization initiator as needed. 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-type compound, an organic peroxide, etc. are mentioned, You may use 2 or more types together. As the azo compound, for example, 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 1,1'-azobis(cyclohexane 1- carbonitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethyl-4-methoxyvaleronitrile), 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. are mentioned.

Examples of the organic peroxide include benzoyl peroxide, t-butylperbenzoate, cumene hydroperoxide, diisopropylperoxydicarbonate, di-n-propylperoxydicarbonate, di(2-ethoxyethyl)peroxydi carbonate, t-butylperoxyneodecanoate, t-butylperoxypivalate, (3,5,5-trimethylhexanoyl)peroxide, dipropionylperoxide, diacetyl peroxide, and the like.

Moreover, the said polymerization process WHEREIN: By mix|blending chain transfer agents, such as 2-mercaptoethanol, the weight average molecular weight of the polymer obtained can be adjusted.

If the (meth)acrylic acid ester polymer (A) can be obtained, in the solution of the (meth)acrylic acid ester polymer (A), a silane coupling agent (B) having a mercapto group, and optionally a crosslinking agent (C), an additive and a diluting solvent are added and mixed sufficiently to obtain an adhesive composition (P) diluted with a solvent (coating solution).

Examples of the diluting solvent include aliphatic hydrocarbons such as hexane, heptane and cyclohexane, aromatic hydrocarbons such as toluene and xylene, halogenated hydrocarbons such as methylene chloride and ethylene chloride, methanol, ethanol, propanol, butanol, 1- Alcohols such as methoxy-2-propanol, ketones such as acetone, methyl ethyl ketone, 2-pentanone, isophorone and cyclohexanone, esters such as ethyl acetate and butyl acetate, and cellosolve solvents such as ethyl cellosolve etc are used.

The concentration and viscosity of the coating solution prepared in this way may be within a range that can be coated, and is not particularly limited, and may be appropriately selected depending on the situation. For example, it is diluted so that the density|concentration of an adhesive composition (P) may be 10-40 mass %. In addition, when obtaining a coating solution, addition of a diluting solvent etc. is not a necessary condition, and as long as the adhesive composition (P) is a coating-able viscosity etc., it is not necessary to add a dilution solvent. In this case, the adhesive composition (P) turns into a coating solution which uses the polymerization solvent of the (meth)acrylic acid ester polymer (A) as a dilution solvent as it is.

[adhesive]

The adhesive which concerns on this embodiment bridge|crosslinks the above-mentioned adhesive composition (P). Crosslinking of the adhesive composition (P) can be performed by heat treatment. In addition, this heat treatment can also serve as a drying process at the time of volatilizing the dilution solvent etc. of the apply|coated adhesive composition (P).

When heat-processing, it is preferable that heating temperature is 50-150 degreeC, and it is especially preferable that it is 70-120 degreeC. Moreover, it is preferable that they are 30 second - 10 minutes, and, as for heating time, it is especially preferable that they are 50 second - 2 minutes. After the heat treatment, if necessary, a curing period of about 1 to 2 weeks may be formed at normal temperature (eg, 23°C, 50%RH). When this curing period is required, an adhesive layer is formed after completion|finish of heat processing, when a curing period is unnecessary after the lapse of a curing period.

It is preferable that the lower limit of the gel fraction of the adhesive which concerns on this embodiment is 30 % or more, It is especially preferable that it is 40 % or more, Furthermore, it is preferable that it is 50 % or more. When the lower limit of the gel fraction of the pressure-sensitive adhesive is equal to or higher than the above, the cohesive force of the pressure-sensitive adhesive becomes high, and it becomes excellent in followability to steps under high-temperature, high-humidity conditions. The upper limit of the gel fraction is preferably 90% or less, particularly preferably 85% or less, and further preferably 80% or less. If the upper limit of the gel fraction of an adhesive is below the said, an adhesive does not become hard too much, but it becomes the thing excellent in step|step difference followability at the time of sticking. Here, the measuring method of the gel fraction of an adhesive is as showing in the test example mentioned later.

[Adhesive sheet]

As shown in FIG. 1, the adhesive sheet 1 which concerns on this embodiment may contact with the peeling surfaces of the peeling sheets 12a, 12b of 2 sheets, and the peeling sheets 12a, 12b of these 2 sheets. It is comprised from the adhesive layer 11 clamped by the said two peeling sheets 12a, 12b. However, in the adhesive sheet 1, the peeling sheets 12a, 12b are not essential components, and peeling and removing at the time of use of the adhesive sheet 1 are carried out. In addition, the peeling surface of the peeling sheet in this specification means the surface which has peelability in a peeling sheet, and it includes any of the surface which gave peeling processing, and the surface which shows peelability even if it does not perform peeling processing.

(1) adhesive layer

The adhesive layer 11 is comprised with the adhesive mentioned above. It is preferable that the lower limit of the thickness (value measured according to JISK7130) of the adhesive layer 11 is 10 micrometers or more, It is especially preferable that it is 25 micrometers or more, Furthermore, it is preferable that it is 50 micrometers or more. When the lower limit of the thickness of the adhesive layer 11 is above-mentioned, the outstanding adhesive force is fully exhibited. Moreover, it is preferable that it is 300 micrometers or less, and, as for the upper limit of the thickness of the adhesive layer 11, it is especially preferable that it is 250 micrometers or less, Furthermore, it is preferable that it is 100 micrometers or less. When the upper limit of the thickness of the adhesive layer 11 is the said or less, workability becomes favorable. In addition, the adhesive layer 11 may be formed in a single layer, and may be formed by laminating|stacking multiple layers.

(2) release sheet

It does not specifically limit as 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, polyethylene naphthalate film, polybutylene terephthalate Film, polyurethane film, ethylene vinyl acetate film, ionomer resin film, ethylene/(meth)acrylic acid copolymer film, ethylene/(meth)acrylic acid ester copolymer film, polystyrene film, polycarbonate film, polyimide film, fluororesin film or the like is used. Moreover, these crosslinked films are also used. Moreover, these laminated|multilayer films may be sufficient.

It is preferable that the peeling process is given to the peeling surface (particularly, the surface in contact with the adhesive layer 11) of the said peeling sheet 12a, 12b. As a release agent used for a peeling process, the release agent of an alkyd type, a silicone type, a fluorine type, an unsaturated polyester type, a polyolefin type, and a wax type is mentioned, for example. Moreover, among the release sheets 12a and 12b, one release sheet is set as a heavy release type release sheet with a large peeling force, and the other release sheet is a light release type release sheet with a small peel force. It is preferable to

Although there is no restriction|limiting in particular about the thickness of the peeling sheets 12a, 12b, Usually, it is about 20-150 micrometers.

(3) Manufacture of adhesive sheet

As one manufacturing example of the adhesive sheet 1, the coating liquid of the said adhesive composition (P) is apply|coated to the peeling surface of one peeling sheet 12a (or (12b)), and heat-processing is carried out, and the adhesive composition After bridge|crosslinking (P) and forming an application layer, the peeling surface of the other peeling sheet 12b (or (12a)) is piled up on the application layer. By providing a curing period when a curing period is required, when a curing period is unnecessary, the said application layer becomes the adhesive layer 11 as it is. Thereby, the said adhesive sheet 1 is obtained. About the conditions of heat processing and curing, it is as above-mentioned.

As another manufacturing example of the adhesive sheet 1, the coating liquid of the said adhesive composition (P) is apply|coated to the peeling surface of one peeling sheet 12a, it heat-processes, and bridge|crosslinks the adhesive composition (P), , an application layer is formed, and the release sheet 12a with an application layer is obtained. Moreover, the coating liquid of the said adhesive composition (P) is apply|coated to the peeling surface of the other peeling sheet 12b, heat-processing is performed, the adhesive composition (P) is bridge|crosslinked, an application layer is formed, and an application layer is An adhered release sheet 12b is obtained. And the release sheet 12a with an application layer and the release sheet 12b with an application layer are bonded together so that both application layers may mutually contact. When a curing period is required, by providing a curing period, when a curing period is unnecessary, the said laminated|stacked application layer becomes the adhesive layer 11 as it is. Thereby, the said adhesive sheet 1 is obtained. According to this manufacturing example, even when the adhesive layer 11 is thick, it becomes possible to manufacture stably.

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

(4) Adhesion

It is preferable that the lower limit of the adhesive force with respect to the soda-lime glass of the adhesive sheet 1 which concerns on this embodiment is 5 N/25 mm or more, It is especially preferable that it is 8 N/25 mm or more, Furthermore, it is 10 N/25 mm or more by extension. it is preferable If the lower limit of the adhesive force of the adhesive sheet 1 is the said or more, it will be excellent in the level|step difference followable|trackability under high-temperature, high-humidity conditions. On the other hand, the upper limit of the adhesive force is not particularly limited, but considering the ease of peeling from the pressure-sensitive adhesive layer 11 of the release sheets 12a and 12b at the time of use, it is preferably 50 N/25 mm or less, It is especially preferable that it is 30 N/25 mm or less. Moreover, when rework property is also considered, it is preferable that it is 26 N/25 mm or less. In that case, even when a bonding error generate|occur|produces, reuse of a display body structural member becomes easy.

Here, the adhesive force in this specification basically refers to the adhesive force measured by the 180 degree peeling method according to JIS Z 0237:2009, but the measurement sample shall be 25 mm width and 100 mm length, and avoid the said measurement sample. After affixing to a complex and pressurizing at 0.5 Mpa and 50 degreeC for 20 minutes, after leaving it to stand on conditions of normal pressure, 23 degreeC, and 50 %RH for 24 hours, let it measure with 300 mm/min of peeling speed|rate.

[display body]

As for the display body which concerns on this embodiment, the 1st display body structural member which has a level|step difference in the surface on the side bonded at least, a 2nd display body structural member, a 1st display body structural member, and a 2nd display body structural member mutually An adhesive layer to be bonded is provided. The said adhesive layer consists of the adhesive which concerns on this embodiment mentioned above. Here, a 1st display body structural member and/or a 2nd display body structural member have an electrode in the surface of the side (adhesive layer side) bonded at least. As a preferable structure, a 2nd display body structural member has an electrode in the surface by which it is bonded at least.

As a display body, a liquid crystal (LCD) display, a light emitting diode (LED) display, an organic electroluminescence (organic EL) display, electronic paper etc. are mentioned, for example, A touch panel may be sufficient. Moreover, as a display body, the member which comprises them may be sufficient.

It is preferable that a 1st display body structural member is a protective panel which consists of a laminated body etc. which contain them other than a glass plate, a plastic plate, etc. It is preferable that a 1st display body structural member has a level difference in the surface by the side of an adhesive layer, and specifically, has a level difference by a printing layer. It is common that this print layer is formed in the shape of a frame.

It does not specifically limit as said glass plate, For example, chemically strengthened glass, alkali-free glass, quartz glass, soda-lime glass, barium strontium containing glass, aluminosilicate glass, lead glass, borosilicate glass, barium borosilicate glass, etc. can be heard Although the thickness of a glass plate is not specifically limited, Usually, it is 0.1-5 mm, Preferably it is 0.2-2 mm.

It does not specifically limit as said plastic plate, For example, an acrylic plate, a polycarbonate plate, etc. are mentioned. Although the thickness of a plastic plate is not specifically limited, Usually, it is 0.2-5 mm, Preferably it is 0.4-3 mm.

In addition, various functional layers (electrode layer, a silica layer, a hard-coat layer, a glare-proof layer, etc.) may be formed on the single side|surface or both surfaces of the said glass plate or a plastic plate, and the optical member may be laminated|stacked.

The material constituting the print layer is not particularly limited, and a known material for printing is 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. When a lower limit is more than the said thing, concealability, such as making an electric wiring invisible from the viewer side, can fully ensure. Moreover, it is preferable that it is 50 micrometers or less, and, as for an upper limit, it is more preferable that it is 35 micrometers or less, It is especially preferable that it is 25 micrometers or less, It is still more preferable that it is 20 micrometers or less. When an upper limit is below the said, the deterioration of the level difference followable|trackability of the adhesive layer with respect to the said printed layer can be prevented.

The 2nd display body structural member is the optical member which should be affixed to the 1st display body structural member, a display body module (for example, a liquid crystal (LCD) module, a light emitting diode (LED) module, organic electroluminescence (organic EL)) ) module etc.), the optical member as a part of a display body module, or it is a laminated body containing a display body module, Comprising: It is preferable to have an electrode in the surface by the side of an adhesive layer at least.

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

As the electrode, for example, a metal electrode made of copper, silver, etc. (including those in mesh or grid form), a transparent conductive film made of tin-doped indium oxide (ITO), etc. (including patterned ones), etc. can be heard As described above, among the electrodes, a metal electrode containing a metal that is not oxidized as a main component, specifically, a metal electrode made of copper or silver is preferable.

As an example of the display body which concerns on this embodiment, the capacitive touch panel 2 is shown in FIG. The touch panel 2 includes a display module 3, a first film sensor 5a laminated thereon with an adhesive layer 4 interposed thereon, and a first adhesive layer 11 laminated thereon with a first adhesive layer 11 interposed thereon. A 2nd film sensor 5b and the cover material 6 laminated|stacked via the 2nd adhesive layer 11 thereon are provided, and it is comprised. The printed layer 7 is formed on the surface of the cover material 6 by the 2nd adhesive layer 11 side, Therefore, the level|step difference by the presence or absence of the printed layer 7 exists. In this embodiment, the cover material 6 corresponds to the said 1st display body structural member, and the 2nd film sensor 5b corresponds to the said 2nd display body structural member.

At least the 2nd adhesive layer 11 in the said touch panel 2 is the adhesive layer 11 of the said adhesive sheet 1, When the migration prevention effect is considered, the 1st adhesive layer 11 and the 2nd It is preferable that both of the adhesive layers 11 are the adhesive layers 11 of the said adhesive sheet 1. In addition, when the first pressure-sensitive adhesive layer 11 is not the pressure-sensitive adhesive layer 11 of the pressure-sensitive adhesive sheet 1, the pressure-sensitive adhesive constituting the first pressure-sensitive adhesive layer 11 includes an acrylic pressure-sensitive adhesive, a rubber-based pressure-sensitive adhesive, a silicone pressure-sensitive adhesive, A urethane-type adhesive, a polyester-type adhesive, a polyvinyl ether-type adhesive, etc. are mentioned, Especially, an acrylic adhesive is preferable.

The adhesive layer 4 may be formed of the adhesive layer 11 of the said adhesive sheet 1, and may be formed of another adhesive or an adhesive sheet. In the latter case, examples of the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer 4 include an acrylic pressure-sensitive adhesive, a rubber-based pressure-sensitive adhesive, a silicone pressure-sensitive adhesive, a urethane pressure-sensitive adhesive, a polyester pressure-sensitive adhesive, and a polyvinyl ether-based pressure-sensitive adhesive. Among them, an acrylic pressure-sensitive adhesive is preferred. do.

The 1st film sensor 5a and the 2nd film sensor 5b in this embodiment are equipped with the base film 51 and the electrode 52 formed in the base film 51, respectively. Although it does not specifically limit as the base film 51, For example, a polyethylene terephthalate film, an acrylic film, a polycarbonate film, etc. are used.

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

As for the electrode 52 of the 1st film sensor 5a, and the electrode 52 of the 2nd film sensor 5b, normally, one constitutes a circuit pattern in the X-axis direction, and the other forms a circuit pattern in the Y-axis direction. make up

The electrode 52 of the 2nd film sensor 5b in this embodiment is located above the 2nd film sensor 5b in FIG. On the other hand, although the electrode 52 of the 1st film sensor 5a is located above the 1st film sensor 5a in FIG. 2, it is not limited to this, It is below the 1st film sensor 5a. may be located

An example of the manufacturing method of the said touch panel 2 is demonstrated below.

As the adhesive sheet 1, the 1st adhesive sheet 1 and the 2nd adhesive sheet 1 are prepared. One peeling sheet 12a is peeled from the 1st adhesive sheet 1, so that the exposed adhesive layer 11 (1st adhesive layer) may contact the electrode 52 of the 1st film sensor 5a, It bonds with the said 1st film sensor 5a. Moreover, one peeling sheet 12a is peeled from the 2nd adhesive sheet 1, and the exposed adhesive layer 11 (2nd adhesive layer 11) is the electrode 52 of the 2nd film sensor 5b. ), it bonds with the said 2nd film sensor 5b so that it may contact.

And the 1st adhesive layer 11 which peels the other peeling sheet 12b in a 1st adhesive sheet, and the exposed 2nd adhesive layer 11 in the said 2nd film sensor 5b is Both are bonded together so that it may contact|connect the surface (exposed surface of the base film 51 of the 1st film sensor 5b) on the opposite side to the laminated|stacked side. Thereby, the laminated body in which the release sheet 12b, the 2nd adhesive layer 11, the 2nd film sensor 5b, the 1st adhesive layer 11, and the 1st film sensor 5a are laminated|stacked in order is obtained.

Next, the pressure-sensitive adhesive layer 4 formed on the release sheet is bonded to the first film sensor 5a side surface of the laminate (the exposed surface of the base film 51 of the first film sensor 5a). . Then, the release sheet 12b is peeled from the laminate, and with respect to the exposed second adhesive layer 11, the printed layer 7 side of the cover material 6 is attached to the second adhesive layer 11. The said cover material 6 is bonded together so that it may contact. At this time, since the 2nd adhesive layer 11 is excellent in step|step difference followability|trackability at the time of sticking, it is suppressed that a gap|interval and a float generate|occur|produce in the step|step difference vicinity by the printed layer 7 . By the said bonding, the cover material 6, the 2nd adhesive layer 11, the 2nd film sensor 5b, the 1st adhesive layer 11, the 1st film sensor 5a, the adhesive layer 4, and peeling A constitution in which sheets are sequentially laminated is obtained.

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

Even when the touch panel 2 is placed under a high-temperature and high-humidity condition and a voltage is applied to the electrode 52 in that state, the pressure-sensitive adhesive layer 11 in contact with the electrode 52 is a silane having a mercapto group. By containing the component derived from a coupling agent (B), migration of the electrode 52 is suppressed effectively. Thereby, the drive failure of the touch panel 2 resulting from the disconnection or short circuit of the electrode 52 is prevented.

In addition, since the pressure-sensitive adhesive layer 11 has excellent step followability even under high-temperature, high-humidity conditions, the touch panel 2 is exposed to high-temperature, high-humidity conditions for a predetermined time (for example, at 85° C., 85% RH for 72 hours). Even in this case, generation|occurrence|production of a bubble, a float, peeling, etc. in the step|step difference vicinity by the printed layer 7 is suppressed effectively.

The embodiments described above are described in order to facilitate understanding of the present invention, and are not described in order to limit the present invention. Accordingly, each element disclosed in the above embodiment is intended to include all design changes and equivalents falling within the technical scope of the present invention.

For example, either one of the peeling sheets 12a and 12b in the adhesive sheet 1 may be abbreviate|omitted.

Example

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

[Example 1]

1. Preparation of (meth)acrylic acid ester copolymer

60 mass parts of 2-ethylhexyl acrylate, 20 mass parts of methyl methacrylate, and 20 mass parts of acrylic acid 2-hydroxyethyl were copolymerized, and the (meth)acrylic acid ester polymer (A) was prepared. As a result of measuring the molecular weight of this (meth)acrylic acid ester polymer (A) by the method mentioned later, it was 600,000 weight average molecular weights (Mw).

2. Preparation of adhesive composition

100 parts by mass of the (meth)acrylic acid ester polymer (A) obtained in the step 1 (solid content conversion; the same hereinafter), and 3-mercaptopropyltrimethoxysilane and methyl as a silane coupling agent (B) having a mercapto group Triethoxysilane co-condensate (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "X-41-1810", oligomer type, mercapto group equivalent: 450 g/mol) 0.05 parts by mass and trimethylolpropane modified as a crosslinking agent (C) 0.23 parts by mass of tolylene diisocyanate (manufactured by Nippon Polyurethane, product name "Colonate L") was mixed, stirred sufficiently, and diluted with methyl ethyl ketone to obtain a coating solution of the adhesive composition having a solid content concentration of 38 mass%.

Here, each compounding (solid content conversion value) of the adhesive composition at the time of making the (meth)acrylic acid ester polymer (A) 100 mass parts (solid content conversion value) is shown in Table 1. In addition, details, such as abbreviation of Table 1, are as follows.

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

2EHA: 2-ethylhexyl acrylate

MMA: methyl methacrylate

HEA: 2-hydroxyethyl acrylate

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

X-41-1810: Cocondensate of 3-mercaptopropyltrimethoxysilane and methyltriethoxysilane (Shin-Etsu Chemical Co., Ltd., trade name “X-41-1810”, oligomer type, mercapto group equivalent: 450 g /mole)

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

[Other Silane Coupling Agents]

KBM-403: 3-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Silicone, trade name "KBM-403", low molecular weight)

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

3. Preparation of adhesive sheet

The peeling-treated surface of a medium-peelable release sheet (manufactured by Lintec, trade name "SP-PET382150", thickness: 38 µm) in which the coating solution of the pressure-sensitive adhesive composition obtained in step 2 was subjected to peeling treatment on one side of the polyethylene terephthalate film with a silicone-based release agent. Then, after apply|coating with a knife coater, it heat-processed at 90 degreeC for 1 minute, and the coating layer (thickness: 25 micrometers) was formed. Similarly, the coating solution of the pressure-sensitive adhesive composition obtained in step 2 was applied to the release treatment side of a light-peelable release sheet (manufactured by Lintec, product name “SP-PET382120”) in which one side of the polyethylene terephthalate film was peeled off with a silicone-based release agent, After apply|coating with a knife coater, it heat-processed at 90 degreeC for 1 minute, and the coating layer (thickness: 25 micrometers) was formed.

Next, the medium release type release sheet with an application layer obtained above and the light release type release sheet with an application layer obtained above were bonded together so that both application layers were in contact with each other, and 7 under the conditions of 23°C and 50%RH By daily curing, a pressure-sensitive adhesive sheet having the structure of a medium 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]

Same as Example 1 except that the type and ratio of the silane coupling agent (the silane coupling agent having a mercapto group (B) and another silane coupling agent) and the ratio of the crosslinking agent (C) are changed as shown in Table 1 to prepare an adhesive sheet. In Comparative Examples 7 to 10, as a rust inhibitor, N,N-bis(2-ethylhexyl)-(4 or 5)-methyl-1H-benzotriazole-1-methylamine (manufactured by BASF, trade name “IRGMET”) 39') was blended into the pressure-sensitive adhesive composition in the proportions shown in Table 1.

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

<Measurement conditions>

・GPC measuring device: HLC-8020, manufactured by Tosoh Corporation

・GPC column (passed in the following order): manufactured by 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 pressure-sensitive adhesive sheets obtained in Examples and Comparative Examples were cut to a size of 80 mm × 80 mm, the pressure-sensitive adhesive layer was wrapped with a polyester mesh (mesh size 200), the mass was weighed with a precision balance, and the mesh alone was By subtracting the mass, the mass of only the adhesive was computed. Let the mass at this time be M1.

Next, the adhesive wrapped in the said polyester mesh was immersed in ethyl acetate at room temperature (23 degreeC) for 24 hours. After that, the pressure-sensitive adhesive was taken out, and in an environment of a temperature of 23°C and a relative humidity of 50%, it was air-dried for 24 hours, and further dried in an oven at 80°C for 12 hours. After drying, the mass was measured with a precision balance, and the mass of only the adhesive was computed by subtracting the mass of the said mesh independent. Let the mass at this time be M2. The gel fraction (%) is represented by (M2/M1) x 100. A result is shown in Table 2.

[Test Example 2] (Measurement of adhesive force)

The light-peelable release sheet was peeled from the pressure-sensitive adhesive sheet obtained in Examples and Comparative Examples, and the exposed pressure-sensitive adhesive layer was applied to a polyethylene terephthalate (PET) film having an easy-to-adhesive layer (manufactured by Toyobo Corporation, product name “PET A4300”, thickness: 100 micrometer), it bonded together to the easily bonding layer, and obtained the laminated body of a heavy peeling type|mold peeling sheet/adhesive layer/PET film. The obtained laminate was cut into 25 mm width and 100 mm length, and this was used as a sample.

In an environment of 23°C and 50% RH, the medium release type release sheet was peeled from the sample, and the exposed pressure-sensitive adhesive layer was affixed to soda lime glass (manufactured by Nippon Glass Co., Ltd.), 0.5 MPa in an autoclave manufactured by Kurihara Seisakusho Co., Ltd. , at 50 °C, pressurized for 20 minutes. Then, after leaving it to stand under the conditions of 23 degreeC and 50 %RH for 24 hours, using the tensile tester (made by Orientec, Tensilon), the adhesive force (N/N/ 25 mm) was measured. Conditions other than those described herein were measured in accordance with JIS Z 0237:2009. A result is shown in Table 2.

[Test Example 3] (Evaluation of migration prevention effect)

(1) Manufacturing of a wiring board

An etching resist pattern is printed by screen printing on the copper foil surface of a copper clad laminate formed by laminating a copper foil (thickness: 18 µm) and a polyethylene terephthalate film (thickness: 50 µm) (manufactured by Nikkan Kogyo Co., Ltd., product name “Nika Flex”) did Thereafter, unnecessary copper foil was removed by etching to form a comb-shaped electrode. The line width of each electrode was 300 m, and the gap between the electrodes was 50 m.

(2) Evaluation of migration prevention effect

The light-peelable release sheet was peeled from the pressure-sensitive adhesive sheet obtained in Examples and Comparative Examples, and the exposed pressure-sensitive adhesive layer was applied to a polyethylene terephthalate (PET) film having an easy-to-adhesive layer (manufactured by Toyobo Corporation, product name “PET A4300”, thickness: 100 micrometer), it bonded together to the easily bonding layer, and obtained the laminated body of a heavy peeling type|mold peeling sheet/adhesive layer/PET film. Next, the heavy release type release sheet was peeled from the said laminated body, and the exposed adhesive layer was affixed on the said comb-shaped electrode, and this was used as a sample.

The said sample was made to stand still on the wet heat conditions of 85 degreeC and 85 %RH, the voltage of 5V was applied between electrodes in that state, and the migration test was implemented. After 8 hours, 24 hours, and 48 hours from the start of the test, the comb-shaped electrode was observed with an optical microscope (magnification: 10 times), and the migration prevention effect was evaluated based on the evaluation criteria shown below. A result is shown in Table 2.

(double-circle): The dissolution of an electrode (positive electrode) and formation of a dendrite in an electrode (negative electrode) are not seen at all.

(circle): Melting|dissolution is seen only at the edge part of an electrode (positive electrode), and formation of the dendrite in an electrode (negative electrode) is not seen.

x: Dissolution of an electrode (positive electrode) and formation of a dendrite in an electrode (negative electrode) are seen.

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

[Test Example 4] (Evaluation of followability to step difference)

(a) Preparation of samples for evaluation

On the surface of a glass plate (manufactured by NSG Precision Transfer, product name "Corning Glass Eagle XG", length 90 mm x width 50 mm x thickness 0.5 mm), UV-curable ink (manufactured by Teikoku Ink, product name "POS-911 ink") ') was screen-printed in a frame shape (outer shape: 90 mm long x 50 mm wide, 5 mm wide) so that the coating thickness became any one of 5 µm, 10 µm, and 15 µm. Then, UV-curable ink is irradiated (80 W/cm 2 , metal halide lamp 2, etc., lamp height 15 cm, belt speed 10-15 m/min) to cure the printed UV curable ink, A glass plate in which a step having a height: any one of 5 μm, 10 μm, and 15 μm) was formed was prepared.

The light-peelable release sheet was peeled off from the pressure-sensitive adhesive sheet obtained in Examples and Comparative Examples, and the exposed pressure-sensitive adhesive layer was applied to the easily-adhesive layer of a polyethylene terephthalate film having an easily-adhesive layer (manufactured by Toyobo, PET A4300, thickness: 100 µm). was pasted. Next, the heavy release type release sheet was peeled off, and the pressure-sensitive adhesive layer was exposed. Then, using a laminator (manufactured by Fujipla Corporation, product name "LPD3214"), the laminate was laminated on a glass plate having each step so that the pressure-sensitive adhesive layer covered the entire frame-like print surface, and this was used as a sample for evaluation.

(b) evaluation of samples for evaluation;

After autoclaving the obtained sample for evaluation on 50 degreeC and the conditions of 0.5 Mpa for 30 minutes, it was left to stand at normal pressure, 23 degreeC, 50 %RH for 24 hours. Then, it was stored for 72 hours under the durable conditions of 85 degreeC and 85 %RH. Thereafter, the pressure-sensitive adhesive layer (particularly in the vicinity of the level difference due to the printed layer) was visually confirmed, and the following standards evaluated the level difference followability. A result is shown in Table 2.

(double-circle) : There were no foam|bubble and float at all.

(circle): Less than 10 air|bubble was seen in the step|step difference vicinity.

x: There were bubbles and/or floating.

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

The adhesive layer of the adhesive sheet obtained by the Example or the comparative example was pinched|interposed between the alkali free glass 2 sheets of thickness 1.1mm, and the laminated body was made into the sample. The obtained sample was stored under the conditions of 85 degreeC and 85 %RH for 120 hours. Then, the haze value of the adhesive layer was measured while returning to 23 degreeC and normal temperature normal humidity of 50 %RH, visually confirming the presence or absence of whitening by the following reference|standards, and evaluating moist-and-heat whitening-resistance. The haze value was measured according to JISK7136:2000 using the haze meter (The Nippon Denshoku Industries Co., Ltd. make, product name "NDH2000") within 30 minutes after returning a sample to normal temperature and normal humidity. A result is shown in Table 2.

(circle): Even if it returned to normal temperature and humidity, whitening was not confirmed. Or some whitening, but disappearing within 30 minutes.

x: It whitened as a whole. Or, after some whitening, it did not return to its original state even when stored at room temperature and humidity.

As Table 2 showed, the adhesive sheet obtained in the Example was a thing excellent in all of the migration prevention effect, step|step difference followable|trackability, and moist-heat-resistance whitening property.

Industrial Applicability

The pressure-sensitive adhesive composition, pressure-sensitive adhesive, and pressure-sensitive adhesive sheet according to the present invention can be preferably used for a capacitive touch panel using a copper electrode or a silver electrode, for example. Moreover, the display body which concerns on this invention is suitable as a capacitive-type touchscreen using a copper electrode or a silver electrode, for example.

(1): adhesive sheet
(11): adhesive layer
(12a), (12b): release sheet
(2): touch panel
(3): display module
(4): adhesive layer
(5a): first film sensor
(5b): second film sensor
(51): base film
(52): electrode
(6): cover material
(7): Printed layer

Claims (10)

It is an adhesive composition which forms the 1st display body structural member which has a level|step difference in the surface on the side to be bonded at least, and the adhesive for bonding a 2nd display body structural member together so that the said level|step difference may be tracked,
The said 1st display body structural member and/or the said 2nd display body structural member have an electrode in the surface at least bonded together,
The adhesive composition,
(meth)acrylic acid ester polymer (A) and;
contains a silane coupling agent (B) having a mercapto group;
Said (meth)acrylic acid ester polymer (A) contains 10 mass % or more and 35 mass % or less of a hydroxyl-containing monomer as a monomer unit which comprises the said polymer, The adhesive composition characterized by the above-mentioned. The method of claim 1,
The silane coupling agent having a mercapto group (B) is an oligomeric silane coupling agent containing a mercapto group. The method of claim 1,
The mercapto group equivalent of the organosilicon compound constituting the silane coupling agent (B) having a mercapto group is 100 g/mol or more and 1000 g/mol or less. The method of claim 1,
The content of the silane coupling agent (B) having a mercapto group in the adhesive composition is 0.01 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the (meth)acrylic acid ester polymer (A) A pressure-sensitive adhesive composition. delete The method of claim 1,
Said adhesive composition further contains a crosslinking agent (C), The adhesive composition characterized by the above-mentioned. The pressure-sensitive adhesive formed by crosslinking the pressure-sensitive adhesive composition according to any one of claims 1 to 4 and 6. The adhesive sheet which has an adhesive layer which consists of the adhesive of Claim 7. 9. The method of claim 8,
The pressure-sensitive adhesive sheet is provided with two release sheets,
The said adhesive layer is pinched|interposed by the said peeling sheet so that it may contact with the peeling surface of the said two peeling sheets, The adhesive sheet characterized by the above-mentioned. 1st display body structural member which has a level|step difference in the surface on the side to which it is pasted at least;
a second display body structural member;
As a display body provided with the adhesive layer which mutually bonds a said 1st display body structural member and a said 2nd display body structural member,
The said 1st display body structural member and/or the said 2nd display body structural member have an electrode in the surface by which it is bonded at least,
The said adhesive layer is an adhesive layer of the adhesive sheet of Claim 8, The display body characterized by the above-mentioned.

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