JP6676429B2 - Adhesive composition, adhesive, adhesive sheet and display - Google Patents

Description

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

  In various mobile electronic devices such as smartphones and tablet terminals in recent years, a touch panel is often used as a display. As a touch panel system, there are a resistive film system, a capacitance system, and the like. In the above-described mobile electronic devices, the capacitance system is mainly employed.

  Recently, as a material for a touch panel, a metal electrode formed of a mesh-shaped metal wiring, for example, a silver electrode, has been studied in place of a transparent conductive film made of tin-doped indium oxide (ITO) or the like. Electrodes are promising. However, when the conventional pressure-sensitive adhesive is used in contact with the metal electrode as described above, the resistance value of the metal electrode changes with the passage of time or high-temperature and high-humidity conditions, and a driving failure of the touch panel may occur.

  Here, Patent Document 1 discloses, as a transparent double-sided pressure-sensitive adhesive sheet that can suppress silver ion migration between metal wirings containing silver or a silver alloy and improve insulation reliability between metal wirings in a touch panel or the like. An acrylic pressure-sensitive adhesive, and a structure selected from the group consisting of a triazole structure, a thiadiazole structure and a benzimidazole structure, and a mercapto group, and having at least one hydrocarbon group that may contain a hetero atom, A compound containing a compound in which the total number of carbon atoms in the hydrocarbon group is 5 or more is disclosed.

Japanese Patent No. 5775494

  By the way, pressure-sensitive adhesives used for displays such as touch panels are required to be colorless and transparent because they are used for optical purposes. However, among the compounds used in the invention disclosed in Patent Document 1, there are compounds that color the adhesive (particularly yellow).

  On the other hand, in the above display, a protection panel is usually provided on the front side of the display module. With the reduction in thickness and weight of mobile electronic devices, the protective panel has been changed from a conventional glass plate to a plastic plate such as an acrylic plate or a polycarbonate plate.

  However, when the above-mentioned plastic plate is used as the protective panel, under high temperature and high humidity conditions, outgas is generated from the plastic plate, and blisters such as bubbles, floating, and peeling are generated at the interface with the adhesive layer. Sometimes. In particular, when a predetermined compound is added to an adhesive as in Patent Document 1, the blister resistance of the adhesive tends to decrease.

  The present invention has been made in view of the above circumstances, and can suppress a change in the resistance value of metal wiring, and is excellent in colorless transparency and blister resistance, an adhesive composition, an adhesive, and an adhesive. It is intended to provide a sheet and a display.

下記構造式（２）で示される骨格を有する化合物（Ｃ）と

（式中、Ｒ^１及びＲ^２は、各々独立して、置換基もしくはヘテロ原子を有していてもよい炭素数１〜２０のアルキル基、置換基もしくはヘテロ原子を有していてもよい炭素数６〜１４のアリール基、または水素原子である。また、Ｒ^３は、水素原子、炭素数１〜４のアルキル基、炭素数１〜４のアルコキシ基、またはハロゲン原子である。）
を含有することを特徴とする粘着性組成物を提供する（発明１）。 In order to achieve the above object, first, the present invention provides a (meth) acrylate polymer (A) and a compound (B) having a skeleton represented by the following structural formula (1):

A compound (C) having a skeleton represented by the following structural formula (2):

(Wherein, R ¹ and R ² each independently represent an alkyl group having 1 to 20 carbon atoms which may have a substituent or a hetero atom, a carbon atom which may have a substituent or a hetero atom, An aryl group having a number of 6 to 14, or a hydrogen atom, and R ³ is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a halogen atom.)
The present invention provides an adhesive composition characterized by containing (invention 1).

  According to the above invention (Invention 1), it is possible to suppress the change in the resistance value of the metal wiring even under a durable condition by the interaction between the ultraviolet absorbing effect of the compound (B) and the rust preventing effect of the compound (C). Can be. Further, since the compound (B) and the compound (C) are nearly colorless and transparent compounds, the resulting pressure-sensitive adhesive has excellent colorless and transparent properties. Further, since the compound (B) and the compound (C) do not inhibit the crosslinking of the (meth) acrylate polymer (A) and do not deteriorate the adhesive strength and the elastic modulus, the obtained adhesive is blister-resistant. It will be excellent in property.

  In the above invention (Invention 1), the content of the compound (C) in the adhesive composition is 0.01 part by mass based on 100 parts by mass of the (meth) acrylate polymer (A). As described above, the content is preferably 2 parts by mass or less (Invention 2).

  The pressure-sensitive adhesive composition according to the above inventions (Inventions 1 and 2) preferably further contains a crosslinking agent (D) (Invention 3).

  The pressure-sensitive adhesive composition according to the above inventions (Inventions 1 to 3) preferably further contains a silane coupling agent (E) (Invention 4).

  In the above inventions (Inventions 1 to 4), the (meth) acrylate polymer (A) has a glass transition temperature (Tg) as a homopolymer of 0 ° C. or lower as a monomer unit constituting the polymer. A reaction in which a (meth) acrylic acid alkyl ester having an alkyl group having 2 to 20 carbon atoms, a monomer having a glass transition temperature (Tg) of more than 0 ° C. as a homopolymer, and a reactive functional group in the molecule It is preferable to contain a functional functional group-containing monomer (Invention 5).

  In the above inventions (Inventions 1 to 5), it is preferred that the (meth) acrylate polymer (A) does not contain a carboxy group-containing monomer as a monomer unit constituting the polymer (Invention 6).

  The pressure-sensitive adhesive composition according to the above inventions (Inventions 1 to 6) is preferably a pressure-sensitive adhesive composition for forming a pressure-sensitive adhesive that comes into contact with metal wiring (Invention 7).

  In the above invention (Invention 7), the metal wiring is preferably made of silver or a silver alloy (Invention 8).

  Secondly, the present invention provides a pressure-sensitive adhesive obtained by crosslinking the pressure-sensitive adhesive composition (Inventions 1 to 8) (Invention 9).

  Thirdly, the present invention includes two release sheets, and an adhesive layer sandwiched between the release sheets so as to be in contact with the release surfaces of the two release sheets, wherein the adhesive layer comprises the adhesive A pressure-sensitive adhesive sheet comprising (Invention 9) is provided (Invention 10).

In the above invention (Invention 10), when the content of the compound (B) in the pressure-sensitive adhesive layer is X mass%, and the thickness of the pressure-sensitive adhesive layer is Ym, the following formula (I) is satisfied. (Invention 11).
50 ≦ X × Y ≦ 500 (I)

  Fourthly, the present invention provides a first display member, a second display member, and an adhesive layer for bonding the first display member and the second display member to each other. Wherein the first display member and / or the second display member has metal wiring on at least a surface to be bonded, and the pressure-sensitive adhesive layer Is a pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet (Inventions 10 and 11).

  Advantageous Effects of Invention According to the pressure-sensitive adhesive composition, pressure-sensitive adhesive, pressure-sensitive adhesive sheet, and display body of the present invention, it is possible to suppress a change in the resistance value of a metal wiring and to have excellent colorless transparency and blister resistance.

It is a sectional view of an adhesive sheet concerning one embodiment of the present invention. It is sectional drawing which shows an example of a structure of a touch panel. FIG. 3 is a plan view of a silver wiring electrode plate used in Test Example 1.

下記構造式（２）で示される骨格を有する化合物（Ｃ）と

（式中、Ｒ^１及びＲ^２は、各々独立して、置換基もしくはヘテロ原子を有していてもよい炭素数１〜２０のアルキル基、置換基もしくはヘテロ原子を有していてもよい炭素数６〜１４のアリール基、または水素原子である。また、Ｒ^３は、水素原子、炭素数１〜４のアルキル基、炭素数１〜４のアルコキシ基、またはハロゲン原子である。）
を含有し、好ましくはさらに架橋剤（Ｄ）およびシランカップリング剤（Ｅ）の少なくとも一つを含有する。本明細書において、（メタ）アクリル酸エステルとは、アクリル酸エステル及びメタクリル酸エステルの両方を意味する。他の類似用語も同様である。また、「重合体」には「共重合体」の概念も含まれるものとする。 Hereinafter, embodiments of the present invention will be described.
(Adhesive composition)
The adhesive composition according to the present embodiment (hereinafter sometimes referred to as “adhesive composition P”) comprises a (meth) acrylate polymer (A) and a skeleton represented by the following structural formula (1). A compound (B) having

A compound (C) having a skeleton represented by the following structural formula (2):

(Wherein, R ¹ and R ² each independently represent an alkyl group having 1 to 20 carbon atoms which may have a substituent or a hetero atom, a carbon atom which may have a substituent or a hetero atom, An aryl group having a number of 6 to 14, or a hydrogen atom, and R ³ is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a halogen atom.)
And preferably at least one of a crosslinking agent (D) and a silane coupling agent (E). In this specification, (meth) acrylate means both acrylate and methacrylate. The same applies to other similar terms. The term “polymer” also includes the concept of “copolymer”.

  The pressure-sensitive adhesive composition P according to the present embodiment is preferably used to form a pressure-sensitive adhesive that comes into contact with metal wiring. Since the adhesive composition P contains the (meth) acrylate polymer (A), the compound (B), and the compound (C), a change in the resistance value of the metal wiring can be suppressed even under a durable condition. If the metal wiring is of a touch panel, the reliability of the touch panel is improved. Such an effect is considered to be due to an interaction between the ultraviolet absorbing effect of the compound (B) and the rust preventing effect of the compound (C). Further, since the compound (B) and the compound (C) are nearly colorless and transparent compounds, the resulting pressure-sensitive adhesive has excellent colorless and transparent properties. Further, since the compound (B) and the compound (C) do not inhibit the crosslinking of the (meth) acrylate polymer (A) and do not deteriorate the adhesive strength and the elastic modulus, the obtained adhesive is blister-resistant. It will be excellent in property.

  Here, examples of the metal wires include metal wires (including mesh, grid, and nanowire shapes) made of silver, silver alloy, copper, copper alloy, and the like. In particular, those constituting the electrodes of the touch panel are preferably exemplified, and specifically, metal wiring included in the film sensor is preferably exemplified. Among the above-described metal wirings, the above-described excellent resistance value change suppressing effect is easily exerted in a metal wiring made of silver or a silver alloy.

(1) (meth) acrylate polymer (A)
The (meth) acrylic acid ester polymer (A) has a glass transition temperature (Tg) of 0 ° C. or less as a homopolymer as a monomer unit constituting the polymer, and the alkyl group has 2 to 20 carbon atoms. (Meth) acrylic acid alkyl ester, a monomer having a glass transition temperature (Tg) of more than 0 ° C. as a homopolymer, and a reactive functional group-containing monomer having a reactive functional group in the molecule. .

  The (meth) acrylic acid ester polymer (A) has a glass transition temperature (Tg) of 0 ° C. or less as a homopolymer as a monomer unit constituting the polymer, and the alkyl group has 2 to 20 carbon atoms. (Meth) acrylic acid alkyl ester (hereinafter sometimes referred to as "low Tg alkyl acrylate"), can exhibit preferable adhesiveness. From this viewpoint, the (meth) acrylic acid ester polymer (A) preferably contains, as a monomer unit constituting the polymer, a low Tg alkyl acrylate as a lower limit of 30% by mass or more, particularly 40% by mass. The content is preferably at least 50% by mass. The (meth) acrylic acid ester polymer (A) preferably contains the low Tg alkyl acrylate as a monomer unit constituting the polymer in an amount of 90% by mass or less as an upper limit value, and particularly preferably 80% by mass or less. And more preferably 70% by mass or less. By containing the low Tg alkyl acrylate in an amount of 90% by mass or less, other monomer components can be introduced into the (meth) acrylate polymer (A) in a suitable amount.

  Examples of the low Tg alkyl acrylate include ethyl acrylate (Tg-20 ° C), n-butyl acrylate (Tg-55 ° C), isobutyl acrylate (Tg-26 ° C), and n-octyl acrylate (Tg-65). ° C), isooctyl acrylate (Tg-58 ° C), 2-ethylhexyl acrylate (Tg-70 ° C), 2-ethylhexyl methacrylate (Tg-10 ° C), isononyl acrylate (Tg-58 ° C), isodecyl acrylate (Tg-60 ° C), isodecyl methacrylate (Tg-41 ° C), n-lauryl acrylate (Tg-23 ° C), n-lauryl methacrylate (Tg-65 ° C), tridecyl acrylate (Tg-55 ° C) , Tridecyl methacrylate (-40 ° C), isostearyl acrylate (Tg-18 ° C) and the like. Among them, from the viewpoint of more effectively imparting tackiness as a low Tg alkyl acrylate, the homopolymer Tg is more preferably -40 ° C or lower, and -50 ° C or lower. Is particularly preferred. Specifically, n-butyl acrylate and 2-ethylhexyl acrylate are particularly preferred. These may be used alone or in combination of two or more. The alkyl group in the alkyl (meth) acrylate having 2 to 20 carbon atoms refers to a linear, branched or cyclic alkyl group.

  In addition, the low Tg alkyl acrylate has a carbon number of the alkyl group of at least part of which is at least partly from the viewpoint of improving the hydrophobicity of the obtained pressure-sensitive adhesive layer and thereby preventing a change in the resistance value of the metal wiring under endurance conditions. It is preferably composed of 5 or more alkyl (meth) acrylates, and more preferably composed of alkyl (meth) acrylate having 7 or more carbon atoms in the alkyl group. Specifically, 2-ethylhexyl acrylate is particularly preferred. In addition, from the viewpoint of preventing a change in the resistance value of the metal wiring, the proportion of the alkyl (meth) acrylate having an alkyl group of 5 or more (preferably 7 or more) in the entire low Tg alkyl acrylate is 40% by mass or more. Is preferably 60% by mass or more, more preferably 80% by mass or more, and most preferably 100% by mass.

  The (meth) acrylic acid ester polymer (A) is a monomer unit constituting the polymer, and a monomer having a glass transition temperature (Tg) of more than 0 ° C. as a homopolymer (hereinafter sometimes referred to as “hard monomer”) Is preferable.) In addition, those corresponding to the reactive functional group-containing monomer described below are excluded from the hard monomer.

  Examples of the hard monomer include methyl acrylate (Tg 10 ° C.), methyl methacrylate (Tg 105 ° C.), ethyl methacrylate (Tg 65 ° C.), n-butyl methacrylate (Tg 20 ° C.), isobutyl methacrylate (Tg 48 ° C.), T-butyl methacrylate (Tg 107 ° C), n-stearyl acrylate (Tg 30 ° C), n-stearyl methacrylate (Tg 38 ° C), cyclohexyl acrylate (Tg 15 ° C), cyclohexyl methacrylate (Tg 66 ° C), phenoxyethyl acrylate (Tg 5 ° C), phenoxyethyl methacrylate (Tg 54 ° C), benzyl methacrylate (Tg 54 ° C), isobornyl acrylate (Tg 94 ° C), isobornyl methacrylate (Tg 180 ° C), acryloylmorpholine (Tg 145 ° C), acrylic Acrylic monomers such as adamantyl (Tg 115 ° C.), adamantyl methacrylate (Tg 141 ° C.), dimethylacrylamide (Tg 89 ° C.), acrylamide (Tg 165 ° C.), vinyl acetate (Tg 32 ° C.), and styrene (Tg 80 ° C.) are preferred. From the viewpoint of compatibility, acrylic monomers are more preferred. These may be used alone or in combination of two or more.

  By containing the hard monomer as a structural unit in the (meth) acrylate polymer (A), the cohesive force of the obtained pressure-sensitive adhesive layer can be improved, and thus the blister resistance can be improved. From such a viewpoint, the glass transition temperature (Tg) of the hard monomer is more preferably 60 ° C. or higher, and particularly preferably 90 ° C. or higher. Further, in consideration of compatibility and copolymerizability with other monomers constituting the (meth) acrylate polymer (A), the glass transition temperature (Tg) of the hard monomer may be 250 ° C. or less. The temperature is preferably 200 ° C. or lower, more preferably 150 ° C. or lower.

  Further, the hard monomer is preferably a (meth) acrylic acid alkyl ester having a linear or branched alkyl group, and is preferably a (meth) acrylic acid alkyl ester having a linear alkyl group. Is more preferably an alkyl methacrylate having a linear alkyl group having 1 to 3 carbon atoms, and most preferably methyl methacrylate. With such a hard monomer, the (meth) acrylate polymer (A) is not bulky and forms a dense crosslinked structure by reducing the distance between the (meth) acrylate polymer (A). When the pressure-sensitive adhesive layer is used, the blister resistance can be further improved.

  From the viewpoint of improving the blister resistance of the obtained pressure-sensitive adhesive layer, the hard monomer is contained in the (meth) acrylate polymer (A) as a monomer constituting the polymer in an amount of 5% by mass or more. , Preferably 10% by mass or more, more preferably 15% by mass or more.

  In addition, the above-mentioned hard monomer is used in order to obtain excellent compatibility between the obtained (meth) acrylate polymer (A) and the compounds (B) and (C) described below. As a constituent monomer, the content is preferably 50% by mass or less, more preferably 40% by mass or less, and particularly preferably 30% by mass or less.

  The (meth) acrylate polymer (A) preferably contains, as a monomer unit constituting the polymer, a reactive functional group-containing monomer having a reactive functional group in the molecule. The reactive functional group derived from the reactive functional group-containing monomer reacts with a crosslinking agent (D) described below, whereby a crosslinked structure (three-dimensional network structure) is formed, and a pressure-sensitive adhesive having a desired cohesive force is obtained. Can be

  The reactive functional group-containing monomer contained in the (meth) acrylate polymer (A) as a monomer unit constituting the polymer includes a monomer having a hydroxyl group in the molecule (hydroxyl group-containing monomer) and a carboxyl group in the molecule. Preferable examples include a monomer having a group (a carboxyl group-containing monomer). Among these, a hydroxyl group-containing monomer which has excellent reactivity with the crosslinking agent (D) and whitening resistance to wet heat and has little adverse effect on metal wiring is particularly preferable.

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

  The (meth) acrylic acid ester polymer (A) preferably contains, as a monomer unit constituting the polymer, a hydroxyl group-containing monomer at a lower limit of 3% by mass or more, particularly preferably 10% by mass or more. Preferably, the content is 15% by mass or more. Further, the (meth) acrylic acid ester polymer (A) preferably contains, as a monomer unit constituting the polymer, a hydroxyl group-containing monomer as an upper limit of 35% by mass or less, and particularly preferably 30% by mass or less. And more preferably 25% by mass or less. When the (meth) acrylic acid ester polymer (A) contains a hydroxyl group-containing monomer in the above amount as a monomer unit, a predetermined amount of a hydroxyl group will remain in the obtained pressure-sensitive adhesive. Hydroxyl groups are hydrophilic groups, and when such hydrophilic groups are present in the adhesive in a certain amount, even if the adhesive is placed under high temperature and high humidity conditions, it will penetrate into the adhesive under the high temperature and high humidity conditions. The adhesive has good compatibility with water, and as a result, whitening of the pressure-sensitive adhesive when returned to normal temperature and normal humidity is suppressed (excellent in wet heat whitening resistance).

  It is preferable that the (meth) acrylate polymer (A) does not contain a carboxyl group-containing monomer as a monomer unit constituting the polymer. This is because the carboxyl group is an acid component, so that there is usually a concern that the resistance value of the metal wiring contacting with the adhesive may change. However, the expression "does not contain a carboxyl group-containing monomer" means that the carboxyl group-containing monomer is allowed to be contained to such an extent that the metal wiring contacted with the obtained adhesive is not adversely affected. Specifically, in the (meth) acrylic acid ester polymer (A), a carboxyl group-containing monomer as a monomer unit is 5% by mass or less, preferably 1% by mass or less, more preferably 0.1% by mass or less. It is acceptable to include it in an amount.

  The (meth) acrylate polymer (A) may contain another monomer as a monomer unit constituting the polymer, if desired. As the other monomer, a monomer containing no reactive functional group is preferable in order not to hinder the action of the reactive functional group-containing monomer. Examples of such other monomers include alkoxyalkyl (meth) acrylates such as methoxyethyl (meth) acrylate and ethoxyethyl (meth) acrylate. These may be used alone or in combination of two or more.

  The polymerization mode 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 more preferably 400,000 or more. When the lower limit of the weight average molecular weight of the (meth) acrylate polymer (A) is at least the above, the pressure-sensitive adhesive will have more excellent blister resistance. The weight average molecular weight in the present specification is a value in terms of standard polystyrene measured by a gel permeation chromatography (GPC) method.

  The upper limit of the weight average molecular weight of the (meth) acrylate polymer (A) is preferably 1,000,000 or less, particularly preferably 900,000 or less, and more preferably 700,000 or less. preferable. When the upper limit of the weight average molecular weight of the (meth) acrylic acid ester polymer (A) is not more than the above, the pressure-sensitive adhesive has excellent step followability at the time of application.

  In the pressure-sensitive adhesive composition P, one type of the (meth) acrylate polymer (A) may be used alone, or two or more types may be used in combination.

(2) Compound (B)
The compound (B) has a skeleton represented by the aforementioned structural formula (1). The compound (B) suppresses a change in the resistance value of the metal wiring due to the interaction with the compound (C). In particular, since the compound (B) exhibits an ultraviolet absorbing effect, it is possible to suppress deterioration of metal wiring, particularly metal wiring made of silver or a silver alloy due to ultraviolet light, and to improve light resistance. Changes can be suppressed. In addition, since the compound (B) is a compound that is nearly colorless and transparent, the resulting pressure-sensitive adhesive has excellent colorless transparency. Furthermore, since the compound (B) does not inhibit the crosslinking of the (meth) acrylic acid ester polymer (A) and does not deteriorate the adhesive strength or the elastic modulus, the obtained adhesive has excellent blister resistance. Becomes

（式中、ｎは１以上の整数である。）
で示される化合物の他、下記構造式（４）

で示される化合物、下記構造式（５）

で示される化合物、下記構造式（６）

で示される化合物等が好ましく挙げられる。これらは単独で用いてもよいし、２種以上を組み合わせて用いてもよい。 As the compound (B), for example, the following structural formula (3)

(In the formula, n is an integer of 1 or more.)
And the following structural formula (4)

A compound represented by the following structural formula (5)

A compound represented by the following structural formula (6)

And the like. These may be used alone or in combination of two or more.

  As the compound (B), among the above, the compound represented by the structural formula (3) is particularly preferable from the viewpoint of the resistance value change suppressing effect, the colorless transparency, and the blister resistance. In the compound represented by the structural formula (3), n in the formula is an integer of 1 or more, preferably 3 to 13, particularly preferably 7 to 9, and more preferably 8.

The content of the compound (B) in the adhesive composition P is preferably an amount satisfying the following conditions. That is, when the content of the compound (B) in the pressure-sensitive adhesive layer formed by the pressure-sensitive adhesive composition P is X% by mass and the thickness of the pressure-sensitive adhesive layer is Ym, the following formula (I) is satisfied. Preferably, it is an amount.
50 ≦ X × Y ≦ 500 (I)
When the content of the compound (B) satisfies the above condition, the action of the compound (B) is effectively exerted without increasing the transmission hue b * of the pressure-sensitive adhesive layer, and the resistance value of the metal wiring is increased. The change can be suppressed more effectively.

  From the above viewpoint, the lower limit value of X × Y in the above formula (I) is more preferably 60 or more, and particularly preferably 70 or more. Further, the upper limit value of X × Y in the above formula (I) is more preferably 200 or less, and particularly preferably 100 or less.

(3) Compound (C)
Compound (C) has a skeleton represented by the aforementioned structural formula (2). Here, the alkyl group for R ¹ and R ² in the formula of the structural formula (2) may be linear or may have a branched chain, or may have an alicyclic structure. May be provided. Examples of the substituent which the alkyl group or the aryl group may have include a halogen atom, an alkoxy group, a hydroxyl group, a thiol group, a carboxyl group, an amino group, an amide group, and the like. Further, examples of the hetero atom which the alkyl group or the aryl group may have include a nitrogen atom, an oxygen atom and a sulfur atom.

  The compound (C) suppresses a change in the resistance value of the metal wiring due to the interaction with the compound (B). In particular, since the compound (C) exhibits a rust preventive action, it is possible to suppress corrosion of metal wiring, particularly metal wiring made of silver or a silver alloy, and from this viewpoint, it is possible to suppress a change in resistance value. it can. Further, since the compound (C) is a compound that is nearly colorless and transparent, the resulting pressure-sensitive adhesive has excellent colorless transparency. Furthermore, since the compound (C) does not inhibit the cross-linking of the (meth) acrylate polymer (A) and does not deteriorate the adhesive strength or the elastic modulus, the obtained adhesive has excellent blister resistance. Becomes

In the compound represented by the structural formula (2), R ¹ and R ² are preferably an alkyl group having 1 to 20 carbon atoms from the viewpoints of a resistance change suppressing effect, colorless transparency, and blister resistance. It is more preferably an alkyl group having 2 to 15 carbon atoms, particularly preferably an alkyl group having 5 to 10 carbon atoms, and most preferably a 2-ethylhexyl group. From the same viewpoint, R ³ is preferably an alkyl group having 1 to 4 carbon atoms, particularly preferably an alkyl group having 1 to 2 carbon atoms, and most preferably a methyl group.

  The content of the compound (C) in the pressure-sensitive adhesive composition P is preferably at least 0.01 part by mass, more preferably at least 0.01 part by mass, based on 100 parts by mass of the (meth) acrylate polymer (A). It is preferably at least 0.1 part by mass, and more preferably at least 0.2 part by mass. Further, the content is preferably 5 parts by mass or less as an upper limit, particularly preferably 1 part by mass or less, and further preferably 0.5 part by mass or less. When the content of the compound (C) is within the above range, the action of the compound (C) is effectively exhibited, and the change in the resistance value of the metal wiring can be more effectively suppressed and obtained. The colorless transparency of the pressure-sensitive adhesive can be further improved.

(4) Crosslinking agent (D)
The pressure-sensitive adhesive composition P preferably contains a crosslinking agent (D). By containing the crosslinking agent (D), the adhesive composition P crosslinks the (meth) acrylate polymer (A) to form a three-dimensional network structure, and improves the cohesive strength of the obtained adhesive. And the blister resistance can be further improved.

  The cross-linking agent (D) may be any as long as it reacts with the reactive group of the (meth) acrylate polymer (A). For example, an isocyanate-based cross-linking agent, an epoxy-based cross-linking agent, an amine-based cross-linking agent, Melamine crosslinking agents, aziridine crosslinking agents, hydrazine crosslinking agents, aldehyde crosslinking agents, oxazoline crosslinking agents, metal alkoxide crosslinking agents, metal chelate crosslinking agents, metal salt crosslinking agents, ammonium salt crosslinking agents, etc. No. 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 having excellent reactivity with the hydroxyl group. The crosslinking agent (D) may be used alone or in combination of two or more.

  The isocyanate-based crosslinking agent contains at least a polyisocyanate compound. As the polyisocyanate compound, for example, aromatic polyisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, aliphatic polyisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, alicyclic polyisocyanates such as hydrogenated diphenylmethane diisocyanate, etc. And their biuret forms, isocyanurate forms, and adducts which are reaction products with low-molecular-weight active hydrogen-containing compounds such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, and castor oil. Among them, trimethylolpropane-modified aromatic polyisocyanates, particularly trimethylolpropane-modified tolylene diisocyanate, are preferred from the viewpoint of reactivity with hydroxyl groups.

  The content of the crosslinking agent (D) in the adhesive composition P is preferably not less than 0.001 part by mass as a lower limit, based on 100 parts by mass of the (meth) acrylate polymer (A). In particular, it is preferably at least 0.01 part by mass, more preferably at least 0.1 part by mass. The upper limit is preferably 10 parts by mass or less, particularly preferably 5 parts by mass or less, and further preferably 1 part by mass or less.

  When the content of the crosslinking agent (D) is in the above range, the cohesive force of the obtained pressure-sensitive adhesive becomes preferable, and the blister resistance of the pressure-sensitive adhesive is further improved.

(5) Silane coupling agent (E)
The pressure-sensitive adhesive composition P preferably contains a silane coupling agent (E). Accordingly, when the adherend has a glass member, the obtained pressure-sensitive adhesive has improved adhesion to the glass member. Further, even if the adherend is a plastic plate, the obtained adhesive has improved adhesion to the plastic plate. Thereby, the obtained adhesive becomes more excellent in blister resistance.

  The silane coupling agent (E) is an organosilicon compound having at least one alkoxysilyl group in the molecule, which has good compatibility with the (meth) acrylate polymer (A) and is colorless and transparent. Is preferred.

  Examples of the silane coupling agent (E) include polymerizable unsaturated group-containing silicon compounds such as vinyltrimethoxysilane, vinyltriethoxysilane, and methacryloxypropyltrimethoxysilane; 3-glycidoxypropyltrimethoxysilane; Silicon compounds having an epoxy structure such as 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane; mercapto groups such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane and 3-mercaptopropyldimethoxymethylsilane Containing silicon compounds, amino groups such as 3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane Silicon compound, 3-chloropropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, or at least one of them and an alkyl group such as methyltriethoxysilane, ethyltriethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, etc. And condensates with silicon compounds. Among the above, a silicon compound having an epoxy structure and a silicon compound containing a mercapto group, which easily exert an effect of suppressing a change in resistance value to a metal wiring, are preferable. These may be used alone or in combination of two or more.

  The content of the silane coupling agent (E) in the adhesive composition P is preferably at least 0.01 part by mass, based on 100 parts by mass of the (meth) acrylate polymer (A). It is preferably at least 0.05 part by mass, more preferably at least 0.1 part by mass. Further, the content is preferably 1 part by mass or less, particularly preferably 0.5 part by mass or less, and further preferably 0.3 part by mass or less.

(6) Various additives In the pressure-sensitive adhesive composition P, if desired, various additives usually used for acrylic pressure-sensitive adhesives, for example, antistatic agents, tackifiers, antioxidants, light stabilizers, softeners , A filler, a refractive index adjusting agent and the like can be added. However, it is preferable not to add a component for coloring the adhesive. For example, a benzophenone-based ultraviolet absorber, a rosin-based tackifier, and the like have a strong tendency to color the pressure-sensitive adhesive, and thus are preferably not added.

  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 that is removed in a drying step or the like, for example, a polymerization described later. The solvent and the diluting solvent are not included in the adhesive composition P.

(7) Production of Adhesive Composition Adhesive composition P produced (meth) acrylate polymer (A), and obtained (meth) acrylate polymer (A) and compound (B) ) And the compound (C) and, if desired, a crosslinking agent (D), a silane coupling agent (E) and an additive.

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

  Examples of the polymerization initiator include azo compounds and organic peroxides, and two or more of them may be used in combination. Examples of the azo compound include 2,2′-azobisisobutyronitrile, 2,2′-azobis (2-methylbutyronitrile), 1,1′-azobis (cyclohexane 1-carbonitrile), , 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] and the like.

  Examples of the organic peroxide include benzoyl peroxide, t-butyl perbenzoate, cumene hydroperoxide, diisopropyl peroxy dicarbonate, di-n-propyl peroxy dicarbonate, and di (2-ethoxyethyl) peroxy. Examples include dicarbonate, t-butyl peroxy neodecanoate, t-butyl peroxy bivalate, (3,5,5-trimethylhexanoyl) peroxide, dipropionyl peroxide, diacetyl peroxide and the like.

  In the above polymerization step, the weight average molecular weight of the obtained polymer can be adjusted by adding a chain transfer agent such as 2-mercaptoethanol.

  When the (meth) acrylate polymer (A) is obtained, the compound (B), the compound (C) and, if desired, the crosslinking agent (D) are added to the solution of the (meth) acrylate polymer (A). , A silane coupling agent (E), an additive and a diluting solvent are added and thoroughly mixed to obtain an adhesive composition P (coating solution) diluted with the solvent.

  As the diluting solvent, for example, hexane, heptane, aliphatic hydrocarbons such as cyclohexane, toluene, aromatic hydrocarbons such as xylene, methylene chloride, halogenated hydrocarbons such as ethylene chloride, methanol, ethanol, propanol, butanol, Alcohols such as 1-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 are used.

  The concentration and viscosity of the coating solution thus prepared are not particularly limited as long as they can be coated, and can be appropriately selected according to the situation. For example, the adhesive composition P is diluted so that the concentration of the adhesive composition P becomes 10 to 40% by mass. In addition, when obtaining a coating solution, addition of a diluting solvent or the like is not a necessary condition, and the diluting solvent may not be added as long as the viscosity is such that the adhesive composition P can be coated. In this case, the adhesive composition P becomes a coating solution using the polymerization solvent of the (meth) acrylate polymer (A) as a diluting solvent as it is.

(Adhesive)
The pressure-sensitive adhesive according to the present embodiment is obtained by cross-linking the pressure-sensitive adhesive composition P described above. Crosslinking of the adhesive composition P can be performed by a heat treatment. In addition, this heat treatment can also serve as a drying treatment when the diluting solvent or the like of the applied adhesive composition P is volatilized.

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

(Adhesive sheet)
As shown in FIG. 1, the pressure-sensitive adhesive sheet 1 according to this embodiment includes two release sheets 12a and 12b, and the two release sheets 12a and 12b so as to be in contact with the release surfaces of the two release sheets 12a and 12b. , 12b. However, in the pressure-sensitive adhesive sheet 1, the release sheets 12a and 12b are not essential components, but are peeled and removed when the pressure-sensitive adhesive sheet 1 is used. In addition, the release surface of the release sheet in this specification refers to a surface having releasability in the release sheet, and includes both the surface subjected to the release treatment and the surface exhibiting the releasability even without performing the release treatment. .

(1) Pressure-sensitive adhesive layer The pressure-sensitive adhesive layer 11 is composed of the pressure-sensitive adhesive described above. The lower limit of the thickness of the pressure-sensitive adhesive layer 11 (a value measured according to JIS K7130) is preferably 10 μm or more, particularly preferably 25 μm or more, and further preferably 50 μm or more. When the lower limit of the thickness of the pressure-sensitive adhesive layer 11 is equal to or more than the above, excellent adhesive strength is sufficiently exhibited. Further, the upper limit of the thickness of the pressure-sensitive adhesive layer 11 is preferably 300 μm or less, particularly preferably 250 μm or less, and further preferably 100 μm or less. When the upper limit of the thickness of the pressure-sensitive adhesive layer 11 is equal to or less than the above, workability is improved. The pressure-sensitive adhesive layer 11 may be formed as a single layer, or may be formed by laminating a plurality of layers.

(2) Release Sheet The release sheets 12a and 12b are not particularly limited, and a 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 acetate A vinyl film, an ionomer resin film, an ethylene / (meth) acrylic acid copolymer film, an ethylene / (meth) acrylic acid ester copolymer film, a polystyrene film, a polycarbonate film, a polyimide film, a fluororesin film, and the like are used. These crosslinked films are also used. Further, these laminated films may be used.

  The release surfaces of the release sheets 12a and 12b (particularly, the surfaces in contact with the adhesive layer 11) are preferably subjected to a release treatment. Examples of the release agent used in the release treatment include alkyd-based, silicone-based, fluorine-based, unsaturated polyester-based, polyolefin-based, and wax-based release agents. It is preferable that one of the release sheets 12a and 12b is a heavy release type release sheet having a large release force, and the other release sheet is a light release type release sheet having a small release force.

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

(3) Production of pressure-sensitive adhesive sheet As one production example of the pressure-sensitive adhesive sheet 1, a coating liquid of the pressure-sensitive adhesive composition P is applied to a release surface of one release sheet 12a (or 12b), and a heat treatment is performed to perform pressure-sensitive adhesion. After cross-linking the conductive composition P to form a coating layer, the release surface of the other release sheet 12b (or 12a) is overlapped with the coating layer. When a curing period is required, a curing period is provided. When the curing period is not required, the above-mentioned coating layer becomes the pressure-sensitive adhesive layer 11 as it is. Thus, the pressure-sensitive adhesive sheet 1 is obtained. The conditions of the heat treatment and the curing are as described above.

  As another production example of the pressure-sensitive adhesive sheet 1, a coating solution of the pressure-sensitive adhesive composition P is applied to the release surface of one release sheet 12a, and a heat treatment is performed to crosslink the pressure-sensitive adhesive composition P. Is formed to obtain a release sheet 12a with a coating layer. Further, on the release surface of the other release sheet 12b, a coating solution of the above-mentioned adhesive composition P is applied, and heat treatment is performed to crosslink the adhesive composition P to form a coating layer. A release sheet 12b is obtained. Then, the release sheet 12a with the coating layer and the release sheet 12b with the coating layer are bonded together so that the two coating layers are in contact with each other. When a curing period is required, a curing period is provided. When the curing period is not required, the above-mentioned laminated coating layer becomes the pressure-sensitive adhesive layer 11 as it is. Thus, the pressure-sensitive adhesive sheet 1 is obtained. According to this production example, even if the pressure-sensitive adhesive layer 11 is thick, it can be produced stably.

  As a method for 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) Transmission hue b *
The transmission hue b * defined by the CIE1976L * a * b * color system of the pressure-sensitive adhesive layer 11 of the pressure-sensitive adhesive sheet 1 according to the present embodiment is preferably −2.0 or more and 2.0 or less, particularly It is preferably −1.5 or more and 1.5 or less, and more preferably −1.0 or more and 1.0 or less. When the transmission hue b * of the pressure-sensitive adhesive layer 11 is in the above range, the pressure-sensitive adhesive layer 11 can be said to be less colored and excellent in colorless transparency, and is particularly suitable for display use. In the present embodiment, by using the compound (B) and the compound (C), it is possible to achieve the above-described transmission hue b * while suppressing a change in the resistance value of the metal wiring. The method for measuring the transmission hue b * in this specification is as shown in Test Examples described later.

(Display body)
The display body according to the present embodiment includes a first display body constituent member, a second display body constituent member, and an adhesive layer for bonding the first display body constituent member and the second display body constituent member to each other. And The pressure-sensitive adhesive layer is made of the pressure-sensitive adhesive according to the present embodiment described above. Here, the first display body component member and / or the second display body component member have metal wiring on at least a surface to be bonded (adhesive layer side). As a preferred configuration, the second display member has an electrode on at least the surface to be bonded.

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

  It is preferable that the first display member is a protection panel formed of a glass plate, a plastic plate, or the like, or a laminate including them. The first display member may have a step on the surface on the pressure-sensitive adhesive layer side. In this case, specifically, it is preferable to have a step due to the printing layer. This printing layer is generally formed in a frame shape.

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

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

  Various functional layers (electrode layer, silica layer, hard coat layer, anti-glare layer, etc.) may be provided on one or both sides of the glass plate or the plastic plate, and optical members are laminated. You may.

  The material constituting the print layer is not particularly limited, and a known material for printing is used. The thickness of the printing 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 the lower limit is equal to or more than the above, sufficient concealment such as making the electrical wiring invisible to the viewer can be ensured. Further, the upper limit is preferably 50 μm or less, more preferably 35 μm or less, particularly preferably 25 μm or less, and further preferably 20 μm or less. When the upper limit is equal to or less than the above, it is possible to prevent deterioration of the step followability of the pressure-sensitive adhesive layer with respect to the print layer.

  The second display member is an optical member to which the first display member is to be attached, a display module (for example, a liquid crystal (LCD) module, a light emitting diode (LED) module, an organic electroluminescence (organic EL)). Module), an optical member as a part of the display module, or a laminate including the display module, preferably having metal wiring on at least the surface on the side of the adhesive layer.

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

  Examples of the metal wires include metal wires (including mesh, grid, and nanowire shapes) made of silver, silver alloy, copper, copper alloy, and the like. In particular, those constituting the electrodes of the touch panel are preferably exemplified, and specifically, metal wiring included in the film sensor is preferably exemplified. Among the above metal wires, metal wires made of silver or a silver alloy are preferable, and an excellent effect of suppressing the change in resistance by the adhesive layer 11 is easily exerted on the metal wires.

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

  At least the second pressure-sensitive adhesive layer 11 in the touch panel 2 is the pressure-sensitive adhesive layer 11 of the pressure-sensitive adhesive sheet 1, and in consideration of the effect of suppressing a change in resistance value, the first pressure-sensitive adhesive layer 11 and the second pressure-sensitive adhesive layer It is preferable that both 11 are the pressure-sensitive adhesive layers 11 of the pressure-sensitive adhesive sheet 1. When the first pressure-sensitive adhesive layer 11 is not the pressure-sensitive adhesive layer 11 of the pressure-sensitive adhesive sheet 1, the pressure-sensitive adhesive constituting the first pressure-sensitive adhesive layer 11 may be an acrylic pressure-sensitive adhesive, a rubber-based pressure-sensitive adhesive, or a silicone-based pressure-sensitive adhesive. Examples include an adhesive, a urethane-based adhesive, a polyester-based adhesive, and a polyvinyl ether-based adhesive, and among them, an acrylic-based adhesive is preferable.

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

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

  The metal wiring 52 is made of, for example, silver, a silver alloy, copper, a copper alloy, or the like, and usually has a circuit pattern such as a mesh shape or a grid shape.

  Usually, one of the metal wiring 52 of the first film sensor 5a and the metal wiring 52 of the second film sensor 5b forms a circuit pattern in the X-axis direction, and the other forms a circuit pattern in the Y-axis direction.

  The metal wiring 52 of the second film sensor 5b in the present embodiment is located above the second film sensor 5b in FIG. On the other hand, the metal wiring 52 of the first film sensor 5a is located on the upper side of the first film sensor 5a in FIG. 2, but is not limited thereto. May be located on the side.

An example of a method for manufacturing the touch panel 2 will be described below.
As the adhesive sheet 1, a first adhesive sheet 1 and a second adhesive sheet 1 are prepared. One of the release sheets 12a is peeled off from the first pressure-sensitive adhesive sheet 1, and the exposed pressure-sensitive adhesive layer 11 (first pressure-sensitive adhesive layer) is brought into contact with the metal wiring 52 of the first film sensor 5a. And the film sensor 5a. Further, one of the release sheets 12a is peeled off from the second pressure-sensitive adhesive sheet 1, and the exposed pressure-sensitive adhesive layer 11 (second pressure-sensitive adhesive layer 11) is brought into contact with the metal wiring 52 of the second film sensor 5b. It is bonded to the second film sensor 5b.

  Then, the other release sheet 12b of the first pressure-sensitive adhesive sheet is peeled off, and the exposed first pressure-sensitive adhesive layer 11 is connected to the side of the second film sensor 5b on which the second pressure-sensitive adhesive layer 11 is laminated. The two are bonded so as to be in contact with the opposite surface (the exposed surface of the base film 51 of the first film sensor 5b). Thus, a laminate is obtained in which the release sheet 12b, the second pressure-sensitive adhesive layer 11, the second film sensor 5b, the first pressure-sensitive adhesive layer 11, and the first film sensor 5a are sequentially laminated.

  Next, the pressure-sensitive adhesive layer 4 provided on the release sheet is bonded to the surface of the laminate on the first film sensor 5a side (the exposed surface of the base film 51 of the first film sensor 5a). Subsequently, the release sheet 12b is peeled from the laminate, and the cover is placed on the exposed second pressure-sensitive adhesive layer 11 such that the printed layer 7 side of the cover material 6 is in contact with the second pressure-sensitive adhesive layer 11. The material 6 is bonded. By the above bonding, the cover material 6, the second pressure-sensitive adhesive layer 11, the second film sensor 5b, the first pressure-sensitive adhesive layer 11, the first film sensor 5a, the pressure-sensitive adhesive layer 4, and the release sheet are sequentially laminated. Is obtained.

  Finally, the release sheet is peeled off from the above-mentioned 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 durable condition, for example, a long-time (for example, 200 hours) ultraviolet irradiation condition or a high-temperature, high-humidity condition (for example, 85 ° C., 85% RH), Since the pressure-sensitive adhesive layer 11 in contact with the metal wiring 52 contains the compound (B) and the compound (C), a change in the resistance value of the metal wiring 52 is effectively suppressed.

Here, a change in the resistance value of the metal wiring 52 will be specifically described. Using the pressure-sensitive adhesive sheet 1 according to the present embodiment, the pressure-sensitive adhesive layer 11 and a silver wiring electrode plate are bonded to each other, and a durability test is performed on the obtained laminate. Is preferably less than 500%, particularly preferably 200% or less.
Resistance value change rate (%) = (R / R ⁰ ) × 100
(In the formula, R ⁰ is the initial resistance value (Ω) before the durability test, and R is the resistance value (Ω) after the durability test.)
The details of the method of measuring the rate of change of the resistance value of the silver wiring electrode plate are as shown in Test Examples described later.

  Further, since the pressure-sensitive adhesive layer 11 is excellent in colorless and transparent, the obtained touch panel 2 can exhibit good optical characteristics.

  Further, since the pressure-sensitive adhesive layer 11 is excellent in blister resistance, the touch panel 2 is placed under high temperature and high humidity conditions (for example, 85 ° C., 85% RH, 72 hours), and outgassing occurs from the cover material 6 made of a plastic plate or the like. Even when air bubbles occur, generation of blisters such as bubbles, floating, and peeling at the interface between the pressure-sensitive adhesive layer 11 and the cover material 6 is suppressed.

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

  For example, one of the release sheets 12a and 12b in the adhesive sheet 1 may be omitted. In the touch panel 2, the print layer 7 may not be formed on the cover 6.

  Hereinafter, the present invention will be described more specifically 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) acrylate polymer (A) 60 parts by mass of 2-ethylhexyl acrylate, 20 parts by mass of methyl methacrylate, and 20 parts by mass of 2-hydroxyethyl acrylate were copolymerized to give (meth) acrylate Polymer (A) was prepared. When the molecular weight of this (meth) acrylic acid ester polymer (A) was measured by the method described later, the weight average molecular weight (Mw) was 600,000.

（式中、ｎは８である。）
で示される化合物１．０質量部と、化合物（Ｃ）として下記構造式（２）

（式中、Ｒ^１及びＲ^２は２−エチルヘキシル基であり、Ｒ^３はメチル基である。）
で示される化合物０．２質量部と、架橋剤（Ｄ）としてのトリメチロールプロパン変性トリレンジイソシアネート（トーヨーケム社製，製品名「ＢＨＳ８５１５」）０．４質量部と、シランカップリング剤（Ｅ）としての３−グリシドキシプロピルトリメトキシシラン（信越シリコーン社製，製品名「ＫＢＭ−４０３」）０．２質量部とを混合し、十分に撹拌して、メチルエチルケトンで希釈することにより、粘着性組成物の塗布溶液を得た。 2. Preparation of Adhesive Composition 100 parts by mass of (meth) acrylate polymer (A) obtained in the above step 1 (solid content converted value; the same applies hereinafter) and compound (B) represented by the following structural formula (3)

(In the formula, n is 8.)
A compound represented by the following structural formula (2):

(In the formula, R ¹ and R ² are a 2-ethylhexyl group, and R ³ is a methyl group.)
0.2 parts by mass of a compound represented by the formula (1), 0.4 parts by mass of trimethylolpropane-modified tolylene diisocyanate (manufactured by Toyochem Co., Ltd., product name "BHS8515") as a crosslinking agent (D), and a silane coupling agent (E) By mixing with 0.2 parts by mass of 3-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Silicone Co., Ltd., product name “KBM-403”), stirring thoroughly, and diluting with methyl ethyl ketone to obtain an adhesive. A coating solution of the composition was obtained.

Here, each composition (solid content conversion value) of the adhesive composition when the (meth) acrylate polymer (A) is 100 parts by mass (solid content conversion value) is shown in Table 1. The details of the abbreviations and the like described in Table 1 are as follows.
[(Meth) acrylate polymer (A)]
2EHA: 2-ethylhexyl acrylate BA: butyl acrylate MMA: methyl methacrylate HEA: 2-hydroxyethyl acrylate IBXA: isobornyl acrylate ACMO: N-acryloylmorpholine
[Silane coupling agent (E)]
Epoxy: 3-glycidoxypropyltrimethoxysilane (Shin-Etsu Silicone, product name "KBM-403")
Mercapto type: Co-condensation product of 3-mercaptopropyltrimethoxysilane and methyltriethoxysilane (Shin-Etsu Chemical Co., Ltd., product name "X-41-1810", oligomer type)

3. Production of Adhesive Sheet A heavy release type release sheet (manufactured by Lintec, product name “SP-PET382150”) obtained by applying a coating solution of the adhesive composition obtained in the above step 2 to one surface of a polyethylene terephthalate film with a silicone release agent. , Thickness: 38 μm), and then applied with a knife coater, followed by heat treatment at 90 ° C. for 1 minute to form a coating layer (thickness: 75 μm).

  Next, a light release type release sheet (product name "SP-PET 382120" manufactured by Lintec Co., Ltd.) in which the coating layer on the heavy release type release sheet obtained above and one side of the polyethylene terephthalate film were subjected to release treatment with a silicone release agent. Is bonded so that the release-treated surface of the light release type release sheet comes into contact with the coating layer, and cured for 7 days at 23 ° C. and 50% RH, whereby a heavy release type release sheet / adhesive An adhesive sheet having a layer (thickness: 75 μm) / light release type release sheet configuration was prepared.

[Examples 2 to 6, Comparative Examples 1 to 3, Reference Example 1]
(Meth) acrylic acid ester polymer (A) types and proportions of each monomer, compounding amount of compound (B), compounding amount of compound (C), compounding amount of crosslinking agent (D), and silane coupling An adhesive sheet was produced in the same manner as in Example 1, except that the type of the agent (E) was changed as shown in Table 1. In Comparative Example 2, 2,2-dihydroxy-4-methoxybenzophenone was used as an ultraviolet absorber (benzophenone-based) instead of the compound (B).

Here, the above-mentioned weight average molecular weight (Mw) is a weight average molecular weight in terms of polystyrene measured (GPC measurement) using gel permeation chromatography (GPC) under the following conditions.
<Measurement conditions>
・ GPC measuring device: HLC-8020 manufactured by Tosoh Corporation
-GPC column (passed in the following order): TSK guard column HXL-H manufactured by Tosoh Corporation
TSK gel GMHXL (× 2)
TSK gel G2000HXL
-Measurement solvent: tetrahydrofuran-Measurement temperature: 40 ° C

[Test Example 1] (Evaluation of resistance value change)
<Preparation of silver wiring electrode plate>
A silver paste (manufactured by Toyochem Co., Ltd., manufactured by Toyochem Co., Ltd.) The product name “RA FS 088”) was applied in the pattern shown in FIG. Thereafter, a heat treatment was performed at 135 ° C. for 30 minutes to cure the silver paste, thereby obtaining an electrode plate having silver wiring (silver wiring electrode plate).

  As shown in FIG. 3, the silver wiring is composed of a first silver wiring 9a having six comb teeth 91a and a second silver wiring 9b also having six comb teeth 91b on the PET film 8. Was formed as Here, a gap 92a is formed between each of the six comb teeth 91a in the first silver wiring 9a, and similarly, a gap 92a is formed between each of the six comb teeth 91b in the second silver wiring 9b. Are gap portions 92b. In the first silver wiring 9a and the second silver wiring 9b, the five comb teeth 91a of the first silver wiring 9a are located in the gaps 92b of the second silver wiring 9b, respectively. The five comb portions 91b in 9b were formed so as to be located in the gap portions 92a of the first silver wiring 9a, respectively. The six comb teeth portions 91a of the first silver wiring 9a are connected by a connecting portion 93a, and the connecting portion 93a is provided with a pad 94a as a terminal. Similarly, the six comb portions 91b of the second silver wiring 9b are connected by a connecting portion 93b, and the connecting portion 93b is provided with a pad 94b as a terminal.

  The line width of the six comb teeth 91a in the first silver wiring 9a and the line width of the six comb teeth 91b in the second silver wiring 9b are 40 μm, respectively. The distance from the portion 91b was 40 μm.

<Manufacture of measurement sample>
The light-peelable release sheet of the pressure-sensitive adhesive sheet obtained in each of Examples and Comparative Examples was peeled off, and an exposed pressure-sensitive adhesive layer and a polyethylene terephthalate film having one surface subjected to easy adhesion treatment (product name “Lumirror U48”, manufactured by Toray Industries, Inc., The pressure-sensitive adhesive sheet and the polyethylene terephthalate film were bonded together such that the easily-adhesive treated surface (thickness: 125 μm) was in contact with the surface.

  Next, the heavy release type release sheet remaining on the pressure-sensitive adhesive sheet is peeled off, and the exposed pressure-sensitive adhesive layer is brought into contact with the silver wiring of the silver wiring electrode plate obtained in the above step, and the silver wiring 9a is formed. , 9b, the adhesive sheet and the silver wiring electrode plate were bonded so that the pads 94a and 94b of the silver wiring electrode plates were exposed. Thereafter, autoclave treatment was performed at 45 ° C. and 0.5 MPa for 20 minutes to obtain a measurement sample.

<Measurement of resistance value>
The initial resistance value R ⁰ (Ω) of the measurement sample obtained as described above was measured by applying a voltage of 5 V between the pads 94a and 94b of the silver wirings 9a and 9b. Next, the durability test shown below was performed on the measurement sample, and then the resistance value (Ω) was measured in the same manner as above. This was defined as the resistance value R after the durability test. From the obtained measured values, the resistance value change rate was calculated by the following equation.
Resistance value change rate (%) = (R / R ⁰ ) × 100
Then, based on the resistance value change rate calculated above, the resistance value change was evaluated according to the following criteria. Table 1 shows the results.
：: The rate of change in resistance is less than 200% Δ: The rate of change in resistance is 200% or more and 500% or less ×: The rate of change in resistance is more than 500%

−Durability test−
And light: ultraviolet rays fade meter by (manufactured by Suga Test Instruments Co., Ltd., product name "UV fade meter U48"), ultraviolet radiation from the glass side of the sample (illumination 500W ^/ m 2 (300~700nm), integrated light quantity 360MJ ^{/ m} 2) , Test time 200 hours, wet heat: 85 ° C, 85% RH, test time 200 hours (during this time, voltage 5V is continuously applied)

[Test Example 2] (Measurement of transmission hue b *)
For the pressure-sensitive adhesive layers of the pressure-sensitive adhesive sheets obtained in Examples and Comparative Examples, a CIE1976L * a * b * color specification was obtained using a simultaneous photometric spectrophotometer (product name "SQ2000" manufactured by Nippon Denshoku Industries Co., Ltd.). The transmission hue b * defined by the system was measured. Table 1 shows the results.

[Test Example 3] (Evaluation of blister resistance)
The light-peelable release sheet of the pressure-sensitive adhesive sheet obtained in each of Examples and Comparative Examples was peeled off, and an exposed pressure-sensitive adhesive layer and a polyethylene terephthalate film having one surface subjected to easy adhesion treatment (product name “Lumirror U48”, manufactured by Toray Industries, Inc., The pressure-sensitive adhesive sheet and the polyethylene terephthalate film were bonded together such that the easily-adhesive treated surface (thickness: 125 μm) was in contact with the surface.

  Next, the heavy release type release sheet remaining on the pressure-sensitive adhesive sheet is peeled off, and an exposed pressure-sensitive adhesive layer and an acrylic plate made of polymethyl methacrylate (PMMA) (product name “Iupilon sheet MR200 manufactured by Mitsubishi Gas Chemical Company, Inc.) , Thickness: 1 mm), and the obtained laminate was used as a sample.

The sample was autoclaved at 50 ° C. and 0.5 MPa for 30 minutes, and then left at normal pressure, 23 ° C. and 50% RH for 24 hours. Next, it was stored under high temperature and high humidity conditions of 85 ° C. and 85% RH for 72 hours. Thereafter, bubbles at the interface between the pressure-sensitive adhesive layer and the adherend were visually confirmed, and the blister resistance was evaluated according to the following criteria. Table 1 shows the results.
…: There were no bubbles, floating and peeling.
Δ: Only bubbles having a diameter of 0.1 mm or less were generated.
×: Bubbles having a diameter of more than 0.1 mm, floating or peeling occurred.

  As can be seen from Table 1, according to the pressure-sensitive adhesive sheet obtained in the example, a change in the resistance value of the silver wiring electrode plate could be suppressed. Further, the pressure-sensitive adhesive sheets obtained in the examples were excellent in colorless transparency and blister resistance.

  In the pressure-sensitive adhesive sheet obtained in Reference Example 1, although the pressure-sensitive adhesive layer does not contain the compound (C), an effect of suppressing a change in resistance is observed. This is thought to be due to the interaction between the mercapto-based silane coupling agent (E) and the compound (B).

  The pressure-sensitive adhesive composition, pressure-sensitive adhesive, and pressure-sensitive adhesive sheet according to the present invention can be suitably used, for example, in a capacitance-type touch panel using silver electrodes. The display according to the present invention is suitable, for example, as a capacitive touch panel using silver electrodes.

DESCRIPTION OF SYMBOLS 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 ... Metal Wiring 6 Cover material 7 Printing layer 8 PET film 9a First silver wiring 9b Second silver wiring 91a, 91b Comb portions 92a, 92b Gap portions 93a, 93b Connection portions 94a, 94b pad

Claims (13)

(Meth) acrylate polymer (A),
A compound (B) having a skeleton represented by the following structural formula (1):

A compound (C) having a skeleton represented by the following structural formula (2):

(Wherein, R ¹ and R ² each independently represent an alkyl group having 1 to 20 carbon atoms which may have a substituent or a hetero atom, a carbon atom which may have a substituent or a hetero atom, An aryl group having a number of 6 to 14, or a hydrogen atom, and R ³ is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a halogen atom.)
A pressure-sensitive adhesive composition comprising:   The content of the compound (C) in the adhesive composition is 0.01 part by mass or more and 5 parts by mass or less based on 100 parts by mass of the (meth) acrylate polymer (A). The pressure-sensitive adhesive composition according to claim 1, characterized in that:   The pressure-sensitive adhesive composition according to claim 1, further comprising a crosslinking agent (D).   The pressure-sensitive adhesive composition according to any one of claims 1 to 3, further comprising a silane coupling agent (E). The (meth) acrylate polymer (A) is a monomer unit constituting the polymer,
A glass transition temperature (Tg) as a homopolymer of 0 ° C. or lower, and an alkyl (meth) acrylate having 2 to 20 carbon atoms in an alkyl group;
The adhesive composition according to any one of claims 1 to 4, comprising a monomer having a glass transition temperature (Tg) of more than 0C as a homopolymer. The said (meth) acrylic-ester polymer (A) contains the reactive functional group containing monomer which has a reactive functional group in a molecule | numerator as a monomer unit which comprises the said polymer. The pressure-sensitive adhesive composition according to any one of claims 1 to 5. The pressure-sensitive adhesive according to any one of claims 1 to 6 , wherein the (meth) acrylate polymer (A) does not contain a carboxy group-containing monomer as a monomer unit constituting the polymer. Composition. The pressure-sensitive adhesive composition according to any one of claims 1 to 7 , which is a pressure-sensitive adhesive composition for forming a pressure-sensitive adhesive that comes into contact with metal wiring. The adhesive composition according to claim 8 , wherein the metal wiring is made of silver or a silver alloy. A pressure-sensitive adhesive obtained by crosslinking the pressure-sensitive adhesive composition according to any one of claims 1 to 9 . Two release sheets,
An adhesive layer sandwiched between the release sheets so as to be in contact with the release surfaces of the two release sheets,
A pressure-sensitive adhesive sheet, wherein the pressure-sensitive adhesive layer is made of the pressure-sensitive adhesive according to claim 10 . Wherein X wt% and the content of the compound in the pressure-sensitive adhesive layer (B), according to claim 11, wherein the thickness of the adhesive layer when the Ymyuemu, the following formula (I), characterized in that the established The pressure-sensitive adhesive sheet according to 1.
50 ≦ X × Y ≦ 500 (I) A first display member,
A second display member,
A display body comprising: an adhesive layer for bonding the first display body constituent member and the second display body constituent member to each other;
The first display member and / or the second display member have metal wiring on at least the surface to be bonded,
Display body in which the pressure-sensitive adhesive layer, characterized in that it is a pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet according to claim 11 or 12.

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