Adhesive composition, adhesive, adhesive sheet, and display

Abstract

The present invention provides an adhesive composition, an adhesive, an adhesive sheet, and a display body that can effectively prevent and inhibit migration. The present invention provides an adhesive composition containing a (meth)acrylate polymer (A), a rust preventive (B), and a long-chain alkyl amine (C); an adhesive crosslinked from the adhesive composition; and an adhesive sheet (1) provided with two release sheets (12a), (12b) and an adhesive layer (11) held by the release sheets (12a), (12b) in contact with the release surfaces of the two release sheets (12a), (12b), and the adhesive layer (11) is composed of the above-mentioned adhesive.

Description

Technical Field

[0001] The present invention relates to adhesive compositions, adhesives and adhesive sheets that can be used in displays such as touch panels, and displays using the same. Background Technology

[0002] In recent years, touch panels have been widely used as displays in various mobile electronic devices such as smartphones and tablets. Types of touch panels include resistive film and capacitive types, with capacitive types being the primary method used in the mobile electronic devices described above.

[0003] The recent trend towards larger touch panels has led to research into mesh-like metal electrodes, such as copper or silver electrodes, as electrode materials for these panels. However, when conventional adhesives are used in contact with metal electrodes, particularly copper or silver electrodes, ion migration (electrochemical migration; hereinafter referred to as "migration") sometimes occurs. Specifically, this can result in electrode dissolution and wire breakage at the positive electrode, or short circuits in the negative electrode due to dendrite formation caused by the precipitation of positive electrode components.

[0004] This migration is particularly prone to occur when voltage is applied to the electrodes under high temperature and humidity conditions. If such migration occurs, the resistance value changes, and the touch panel cannot operate properly. In recent years, especially with the miniaturization and narrowing of electrode spacing, electrode breakage or short circuits caused by migration are more likely to occur, necessitating effective prevention and suppression of migration.

[0005] In addition, Patent Document 1 discloses an adhesive composition for touch panels containing a benzotriazole compound as a rust inhibitor.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2014-177611 Summary of the Invention

[0009] The technical problem to be solved by the present invention

[0010] However, even though benzotriazole compounds, as rust inhibitors, have anti-corrosion effects on metal wiring, they cannot adequately prevent and inhibit migration.

[0011] The present invention was made in view of the above-mentioned actual situation, and its object is to provide an adhesive composition, adhesive, adhesive sheet and display body that can effectively prevent and inhibit migration.

[0012] Technical means to solve technical problems

[0013] To achieve the above objectives, firstly, the present invention provides an adhesive composition characterized in that it contains a (meth)acrylate polymer (A), a rust inhibitor (B), and a long-chain alkylamine (C) (Invention 1).

[0014] According to the invention described above (Invention 1), through the coexistence of rust inhibitor (B) and long-chain alkylamine (C), rust inhibitor (B) readily and stably exists on the surface of the adhesive layer obtained from the adhesive composition. Therefore, when the adhesive layer comes into contact with the electrode, electrode dissolution can be prevented and suppressed in the positive electrode, and dendrite formation can be prevented and suppressed in the negative electrode. That is, migration within the electrode can be effectively prevented and suppressed, and changes in the resistance value of electrodes composed of metals or metal oxides can be suppressed.

[0015] In the above invention (Invention 1), it is preferred to contain a silane compound (D) having alkoxysilyl groups at both ends (Invention 2).

[0016] In the above inventions (Inventions 1 and 2), it is preferred to contain alkylene glycol (E) (Invention 3).

[0017] In the above inventions (Inventions 1 to 3), the rust inhibitor (B) is preferably an azole (Invention 4).

[0018] In the above inventions (Inventions 1 to 4), the long-chain alkylamine (C) is preferably a tertiary amine (Invention 5).

[0019] In the above inventions (Inventions 1 to 5), it is preferable to include a crosslinking agent (F) (Invention 6).

[0020] In the above inventions (Inventions 1 to 6), it is preferable that the (meth)acrylate polymer (A) does not contain carboxyl-containing monomers as monomer units constituting the polymer (Invention 7).

[0021] In the above inventions (Inventions 1 to 7), it is preferable that the (meth)acrylate polymer (A) contains 6% by mass or more and 35% by mass or less of hydroxyl-containing monomers as monomer units constituting the polymer (Invention 8).

[0022] The inventions described above (Inventions 1-8) may also contain an ultraviolet absorber (Invention 9).

[0023] In the above inventions (Inventions 1 to 9), an adhesive composition for forming an adhesive that contacts an electrode made of metal or metal oxide is preferred (Invention 10).

[0024] Second, the present invention provides an adhesive which is formed by crosslinking the adhesive compositions (Inventions 1-10) (Invention 11).

[0025] Third, the present invention provides an adhesive sheet, characterized in that it comprises two release tabs and an adhesive layer sandwiched between the release tabs in a manner that contacts the release surfaces of the two release tabs, the adhesive layer being composed of the adhesive (Invention 11) (Invention 12).

[0026] Fourth, the present invention provides a display body comprising: a first display body component, a second display body component, and an adhesive layer for bonding the first display body component and the second display body component together, wherein the display body is characterized in that the first display body component and / or the second display body component have electrodes made of metal or metal oxide on at least one side of the surface to which they are bonded, and the adhesive layer is composed of the adhesive (Invention 11) (Invention 13).

[0027] Invention Effects

[0028] The adhesive compositions, adhesives, adhesive sheets, and displays according to the present invention can effectively prevent and inhibit migration. Attached Figure Description

[0029] Figure 1 This is a cross-sectional view of an adhesive sheet according to one embodiment of the present invention.

[0030] Figure 2 This is a cross-sectional view showing an example of the configuration of a display (touch panel).

[0031] Explanation of reference numerals in the attached figures

[0032] 1: Adhesive sheet; 11: Adhesive layer; 12a, 12b: Release sheet; 2: Touch panel; 3: Display module; 4: Adhesive layer; 5a: First membrane sensor; 5b: Second membrane sensor; 51: Substrate film; 52: Electrode; 6: Covering material; 7: Printed layer. Detailed Implementation

[0033] The following describes the embodiments of the present invention.

[0034] [Adhesive Composition]

[0035] The adhesive composition of this embodiment (hereinafter, sometimes referred to as "adhesive composition P") contains a (meth)acrylate polymer (A), a rust inhibitor (B), and a long-chain alkylamine (C), preferably further containing at least one of a silane compound (D) having alkoxysilyl groups at both ends, an alkylene glycol (E), and a crosslinking agent (F). In this specification, (meth)acrylate refers to both acrylates and methacrylates. Other similar terms are also used. Furthermore, "polymer" also includes the concept of "copolymer".

[0036] The adhesive composition P of this embodiment is preferably used to form an adhesive that contacts an electrode made of metal or metal oxide. By including the above-mentioned components in the adhesive composition P, when the adhesive obtained from the adhesive composition P contacts the electrode, electrode dissolution can be prevented and suppressed in the positive electrode, and dendrite formation can be prevented and suppressed in the negative electrode. That is, migration in the electrode can be effectively prevented and suppressed (sometimes referred to as the "anti-migration effect"), and changes in the resistance value of the electrode made of metal or metal oxide can be suppressed. Furthermore, by effectively preventing and suppressing migration, even when the adhesive contacts, for example, a miniaturized, narrow-pitch electrode, electrode breakage or short circuit can be prevented. In particular, when the electrode is an electrode of a touch panel, malfunction of the touch panel caused by electrode breakage or short circuit can be prevented.

[0037] Examples of electrodes include metal electrodes (including mesh and grid electrodes) made of copper, copper alloys, silver, or silver alloys, and transparent conductive films (including patterned conductive films) made of tin-doped indium oxide (ITO). Among these electrodes, metal electrodes with an unoxidized metal as the main component are preferred; specifically, metal electrodes made of copper, copper alloys, silver, or silver alloys are preferred, and metal electrodes made of silver or silver alloys are particularly preferred. Examples of silver alloys include alloys formed by adding palladium and copper to silver. Although unoxidized metals have a higher ionization tendency than metal oxides such as ITO, the adhesive obtained from the adhesive composition P of this embodiment can effectively prevent electrode breakage or short circuits even in this case.

[0038] While the reasons for the aforementioned effects are not yet clear, the following speculation is made. In the adhesive layer obtained from the adhesive composition P, the rust inhibitor (B) and the long-chain alkylamine (C) have molecular structures much smaller than the crosslinked body of the (meth)acrylate polymer (A), which has a large molecular structure, and both tend to segregate easily on the surface of the adhesive layer. Furthermore, the long-chain alkylamine (C) is suitably distributed on the surface of the adhesive layer, making it easier for the rust inhibitor (B) to be stably distributed closer to the surface of the adhesive layer or around the long-chain alkylamine (C) than it is on the surface of the adhesive layer. Therefore, in the adhesive layer obtained from the adhesive composition P, compared to an adhesive layer that does not contain the long-chain alkylamine (C), the rust inhibitor (B) is more likely to be stably present on the surface of the adhesive layer. In addition, since the rust inhibitor (B) is a lower molecular weight than the long-chain alkylamine (C), it can be speculated that the amount of segregated on the surface of the adhesive layer is also greater, and the proportion present on the surface is higher. That is, through the coexistence of rust inhibitor (B) and long-chain alkylamine (C), rust inhibitor (B) can easily and stably exist on the surface of the adhesive layer, and can easily and effectively exert its function. Therefore, it can be inferred that the adhesive layer can exert excellent anti-migration effect.

[0039] Furthermore, the adhesive obtained from the adhesive composition P of this embodiment can be an active energy ray-curable adhesive that is cured by irradiation with active energy rays, or an inactive energy ray-curable adhesive that is cured without irradiation with active energy rays. When it is an active energy ray-curable adhesive, the adhesive composition P preferably further contains an active energy ray-curable component (G).

[0040] (1) Each ingredient

[0041] (1-1) (Meth)acrylate polymer (A)

[0042] The (meth)acrylate polymer (A) preferably contains a monomer with reactive functional groups within its molecule as the monomer constituting the polymer. By containing this monomer with reactive functional groups, and through the reaction of the reactive functional groups from this monomer with the crosslinking agent (F) described below, a crosslinked structure (three-dimensional network structure) is formed, thereby obtaining an adhesive with a specified cohesive strength.

[0043] As monomers containing reactive functional groups and constituting monomer units in (meth)acrylate polymer (A), preferably include monomers with intramolecular hydroxyl groups (hydroxyl-containing monomers), monomers with intramolecular carboxyl groups (carboxyl-containing monomers), and monomers with intramolecular amino groups (amino-containing monomers). These monomers containing reactive functional groups may be used individually or in combination with two or more monomers.

[0044] Among the above-mentioned monomers containing reactive functional groups, hydroxyl-containing monomers with excellent reactivity with crosslinking agent (F) and minimal adverse effects on the electrode are particularly preferred.

[0045] Examples of hydroxyl-containing monomers include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and other hydroxyalkyl (meth)acrylate esters. From the perspective of reactivity with the crosslinking agent (F), 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate are preferred, 2-hydroxyethyl acrylate and 4-hydroxybutyl acrylate are more preferred, and 2-hydroxyethyl acrylate is particularly preferred. These hydroxyl-containing monomers can be used alone or in combination of two or more.

[0046] The (meth)acrylate polymer (A) preferably contains 6% or more by mass, particularly preferably 9% or more by mass, and even more preferably 12% or more by mass of a monomer containing a reactive functional group (especially a hydroxyl-containing monomer) as the monomer unit constituting the polymer. Furthermore, the (meth)acrylate polymer (A) preferably contains 35% or less by mass, particularly preferably 30% or less by mass, and even more preferably 25% or less by mass of a monomer containing a reactive functional group (especially a hydroxyl-containing monomer) as the monomer unit constituting the polymer.

[0047] If the (meth)acrylate polymer (A) contains a monomer with a reactive functional group as a monomer unit in the above-mentioned amount, a good balance between the adhesive force and cohesive force of the obtained adhesive can be achieved. In particular, when the above-mentioned monomer with a reactive functional group is a hydroxyl-containing monomer, if the (meth)acrylate polymer (A) contains a hydroxyl-containing monomer as a monomer unit in the above-mentioned amount, a specified amount of hydrophilic hydroxyl groups will remain in the obtained adhesive. As a result, even in the presence of moisture, the moisture is captured by these hydroxyl groups, thereby inhibiting moisture from penetrating into the electrode adjacent to the adhesive layer and further improving the mitigation effect.

[0048] Preferably, the (meth)acrylate polymer (A) does not contain carboxyl-containing monomers as monomer units constituting the polymer. Since carboxyl groups are acidic components, there is a possibility of changes in resistance due to corrosion of the electrodes contacted by the adhesive. However, by not containing carboxyl-containing monomers, electrode corrosion can be prevented, thereby effectively preventing and suppressing changes in resistance. Here, "not containing carboxyl-containing monomers" means that the presence of carboxyl-containing monomers is permitted to a degree that does not adversely affect the electrodes contacted by the resulting adhesive. Specifically, in the (meth)acrylate polymer (A), the presence of carboxyl-containing monomers as monomer units is permitted in an amount of 0.1% by mass or less, preferably 0.01% by mass or less, and more preferably 0.001% by mass or less.

[0049] Furthermore, the (meth)acrylate polymer (A) preferably contains alkyl (meth)acrylate as a monomer unit constituting the polymer. This allows it to exhibit good adhesion.

[0050] In addition to the monomers containing reactive functional groups mentioned above, it is particularly preferred that the (meth)acrylate polymer (A) contains (meth)acrylate alkyl esters with a glass transition temperature (Tg) of 0°C or less and alkyl groups having 2 to 20 carbon atoms, and monomers with a glass transition temperature (Tg) of more than 0°C as monomer units constituting the polymer.

[0051] By including alkyl methacrylates (hereinafter sometimes referred to as "low-Tg alkyl acrylates") as monomer units constituting the (meth)acrylate polymer (A) with a glass transition temperature (Tg) of 0°C or lower as a homopolymer and 2 to 20 carbon atoms in the alkyl group, the polymer exhibits superior adhesive properties. From this perspective, the (meth)acrylate polymer (A) preferably contains 30% by mass or more, more preferably 40% by mass or more, particularly preferably 50% by mass or more, and further preferably 60% by mass or more as monomer units constituting the polymer. Furthermore, the (meth)acrylate polymer (A) preferably contains 90% by mass or less, particularly preferably 80% by mass or less, and further preferably 70% by mass or less of the aforementioned low-Tg alkyl acrylates as monomer units constituting the polymer, up to the upper limit. If the upper limit of the content of the aforementioned low-Tg alkyl acrylates is as described above, suitable amounts of other monomer components can be introduced into the (meth)acrylate polymer (A).

[0052] Examples of low-Tg alkyl acrylates include, for example, ethyl acrylate (Tg-20℃), n-butyl acrylate (Tg-55℃), isobutyl acrylate (Tg-26℃), n-octyl acrylate (Tg-65℃), isooctyl acrylate (Tg-58℃), 2-ethylhexyl acrylate (Tg-70℃), 2-ethylhexyl methacrylate (Tg-10℃), isononyl acrylate (Tg-58℃), isodecanyl acrylate (Tg-60℃), isodecanyl methacrylate (Tg-41℃), n-lauryl acrylate (Tg-23℃), n-lauryl methacrylate (Tg-65℃), tridecyl acrylate (Tg-55℃), tridecyl methacrylate (-40℃), and isostearyl acrylate (Tg-18℃). Among these, alkyl acrylates with low Tg are preferred from the perspective of more effectively imparting adhesion, especially those with a Tg of -40°C or lower, and particularly preferably those with a Tg of -50°C or lower. Specifically, n-butyl acrylate and 2-ethylhexyl acrylate are particularly preferred, and 2-ethylhexyl acrylate is further preferred from the perspective of inhibiting migration. These low Tg alkyl acrylates can be used alone or in combination. Furthermore, in (meth)acrylates with 2 to 20 carbon atoms, the alkyl group refers to a straight-chain, branched, or cycloalkyl group.

[0053] Furthermore, from the perspective of suppressing migration by improving the hydrophobicity of the obtained adhesive layer, at least a portion of the aforementioned low-Tg alkyl acrylates is preferably an alkyl (meth)acrylate in which the alkyl group has 5 or more carbon atoms, more preferably an alkyl (meth)acrylate in which the alkyl group has 7 or more carbon atoms. Specifically, 2-ethylhexyl acrylate is particularly preferred. Furthermore, from the perspective of suppressing migration, the proportion of alkyl (meth)acrylates in which the alkyl group has 5 or more carbon atoms (preferably 7 or more) in the overall low-Tg alkyl acrylate is preferably 40% by mass or more, more preferably 60% by mass or more, particularly preferably 80% by mass or more, and most preferably 100% by mass.

[0054] Furthermore, by incorporating monomers (hereinafter sometimes referred to as "hard monomers") with a glass transition temperature (Tg) exceeding 0°C into the (meth)acrylate polymer (A) as monomeric units constituting the polymer, the resulting adhesive readily possesses moderate cohesiveness and tackiness. Consequently, even after durability conditions, the resulting adhesive layer is easily protected against defects such as lifting and peeling at the interface with the adhered object.

[0055] Examples of preferred hard monomers include methyl acrylate (Tg10℃), methyl methacrylate (Tg105℃), ethyl methacrylate (Tg65℃), n-butyl methacrylate (Tg20℃), isobutyl methacrylate (Tg48℃), tert-butyl methacrylate (Tg107℃), stearyl acrylate (Tg30℃), stearyl methacrylate (Tg38℃), cyclohexyl acrylate (Tg15℃), cyclohexyl methacrylate (Tg66℃), phenoxyethyl acrylate (Tg5℃), and methacrylic acid. Acrylic monomers such as phenoxyethyl ester (Tg54℃), benzyl methacrylate (Tg54℃), isobornyl acrylate (Tg94℃), isobornyl methacrylate (Tg180℃), acrylmorpholine (Tg145℃), adamantane acrylate (Tg115℃), adamantane methacrylate (Tg141℃), dimethacrylamide (Tg89℃), and acrylamide (Tg165℃), as well as vinyl acetate (Tg32℃) and styrene (Tg80℃), can be more preferably listed from a compatibility perspective. These hard monomers can be used alone or in combination of two or more.

[0056] In particular, from the perspective of imparting suitable cohesiveness and adhesion to the obtained adhesive and effectively suppressing undesirable conditions such as lifting and peeling at the interface with the adhered object, the glass transition temperature (Tg) of the aforementioned hard monomer is more preferably 60°C or higher, and particularly preferably 90°C or higher. Furthermore, considering the compatibility or copolymerization with other monomers constituting the (meth)acrylate polymer (A), the glass transition temperature (Tg) of the aforementioned hard monomer is preferably 250°C or lower, more preferably 200°C or lower, and particularly preferably 150°C or lower.

[0057] From the perspective of preventing adverse effects on compatibility and other properties of other components, and simultaneously further enhancing the performance of the hard monomer, the aforementioned hard monomer preferably contains at least one selected from the group consisting of methyl methacrylate, isobornyl acrylate, and acrylomorpholine. It is particularly preferred to use methyl methacrylate alone, or to use isobornyl acrylate and acrylomorpholine simultaneously.

[0058] From the perspective of imparting suitable cohesiveness and adhesiveness to the obtained adhesive, the (meth)acrylate polymer (A) preferably contains 5% or more by mass, more preferably 10% or more by mass, and particularly preferably 15% or more by mass of the above-mentioned hard monomers as monomers constituting the polymer.

[0059] Furthermore, from the perspective of ensuring excellent compatibility between the obtained (meth)acrylate polymer (A) and other components, it is preferable to use the above-mentioned hard monomers containing 50% or less by mass, more preferably 40% or less by mass, and particularly preferably 30% or less by mass as monomers constituting the polymer.

[0060] The (meth)acrylate polymer (A) may also contain other monomers as constituent units of the polymer, as desired. To avoid hindering the function of monomers containing reactive functional groups, monomers that do not contain reactive functional groups are preferred as other monomers. Examples of other monomers include methoxyethyl methacrylate, ethoxyethyl methacrylate, and alkoxyalkyl methacrylates. These other monomers can be used alone or in combination of two or more.

[0061] The preferred (meth)acrylate polymer (A) is a solution polymer obtained by solution polymerization. By making it a solution polymer, it is easy to obtain a high molecular weight polymer, resulting in an adhesive with excellent durability.

[0062] The polymerization form of (meth)acrylate polymer (A) can be a random copolymer or a block copolymer.

[0063] The lower limit of the weight-average molecular weight of the (meth)acrylate polymer (A) is preferably 200,000 or more, particularly preferably 300,000 or more, and even more preferably 400,000 or more. If the lower limit of the weight-average molecular weight of the (meth)acrylate polymer (A) is as described above, the resulting adhesive exhibits excellent durability, while the rust inhibitor (B) and long-chain alkylamine (C) readily and stably segregate and coexist on the surface of the adhesive layer. Furthermore, the weight-average molecular weight in this specification is a value converted from standard polystyrene determined by gel permeation chromatography (GPC).

[0064] Furthermore, the upper limit of the weight-average molecular weight of the (meth)acrylate polymer (A) is preferably 1.2 million or less, particularly preferably 900,000 or less, and even more preferably 750,000 or less. If the upper limit of the weight-average molecular weight of the (meth)acrylate polymer (A) is as described above, the resulting adhesive will exhibit suitable adhesive properties.

[0065] In addition, in the adhesive composition P, the (meth)acrylate polymer (A) can be used alone or in combination of two or more.

[0066] (1-2) Rust Inhibitor (B)

[0067] As the rust inhibitor (B) in this embodiment, a rust inhibitor suitable for coexisting with the long-chain alkylamine (C) described below on the surface of the adhesive layer is preferred. Since such a rust inhibitor (B) readily and stably exists on the surface of the adhesive layer, it can effectively exert its function, thereby contributing to the prevention of migration. Examples of such rust inhibitors (B) include azole compounds, triazole compounds, benzotriazole compounds, thiazole compounds, benzothiazole compounds, imidazole compounds, benzimidazole compounds, etc., as well as phosphorus compounds, nitrite compounds, etc. Among these, azole compounds are preferred from the perspective of readily segregating and coexisting with the long-chain alkylamine (C) on the surface of the adhesive layer and exhibiting excellent anti-migration effects, and benzotriazole compounds are particularly preferred. The rust inhibitor (B) can be used alone or two or more can be used simultaneously.

[0068] Examples of benzotriazole compounds include 1H-benzotriazole, methyl-1H-benzotriazole, 1-[N,N-bis(2-ethylhexyl)aminomethyl]benzotriazole, 1-[N,N-bis(2-ethylhexyl)aminomethyl]methylbenzotriazole, carboxybenzotriazole, and 2,2'-[[(methyl-1H-benzotriazole-1-yl)methyl]imino]diethanol. Among these, 1H-benzotriazole, methyl-1H-benzotriazole, 1-[N,N-bis(2-ethylhexyl)aminomethyl]benzotriazole, and 1-[N,N-bis(2-ethylhexyl)aminomethyl]methylbenzotriazole are preferred from the perspective of their compatibility with long-chain alkylamines (C). These substances are particularly effective at inhibiting migration.

[0069] The content of rust inhibitor (B) in the adhesive composition P is preferably 0.01 parts by mass or more, more preferably 0.08 parts by mass or more, particularly preferably 0.12 parts by mass or more, and even more preferably 0.15 parts by mass or more, relative to 100 parts by mass of (meth)acrylate polymer (A). This facilitates suitable segregation on the surface of the obtained adhesive layer, resulting in superior migration prevention. Furthermore, the above-mentioned content is preferably 2 parts by mass or less, more preferably 1 part by mass or less, particularly preferably 0.5 parts by mass or less, and even more preferably 0.2 parts by mass or less. This allows for suitable coexistence with long-chain alkylamine (C) on the surface of the obtained adhesive layer, resulting in a good migration prevention effect while maintaining good adhesion.

[0070] (1-3) Long-chain alkylamines (C)

[0071] The long-chain alkylamine (C) in this embodiment is an amine containing a long-chain alkyl group in its molecule. While the long-chain alkyl group is preferably straight-chain, it may have branched chains or a cyclic structure. The number of carbon atoms in the long-chain alkyl group is preferably 10 or more, more preferably 12 or more, and particularly preferably 14 or more. Furthermore, the number of carbon atoms is preferably 24 or less, more preferably 22 or less, particularly preferably 20 or less, and even more preferably 18 or less. Such a long-chain alkylamine (C) readily segregates on the surface of the adhesive layer along with the aforementioned rust inhibitor (B), facilitating the stable presence of the rust inhibitor (B) on the surface. Therefore, the long-chain alkylamine (C) can synergistically exert an excellent anti-migration effect with the rust inhibitor (B).

[0072] In this embodiment, the long-chain alkylamine (C) can be a primary amine, a secondary amine, or a tertiary amine, with a tertiary amine being preferred. By using a tertiary amine, the peel force required to detach the resulting adhesive layer from the release liner can be maintained at a low level, resulting in excellent operability during use.

[0073] Furthermore, the long-chain alkylamine (C) in this embodiment preferably has a hydroxyl group at its end. This hydroxyl group helps to prevent moisture from penetrating into the electrode adjacent to the resulting adhesive layer, thus improving the migration prevention effect.

[0074] Furthermore, the long-chain alkylamine (C) in this embodiment preferably contains an oxyethylene structure, and particularly preferably contains a polyoxyethylene structure. That is, the long-chain alkylamine (C) in this embodiment is preferably an oxyethylene long-chain alkylamine, and particularly preferably a polyoxyethylene long-chain alkylamine. Hereinafter, oxyethylene long-chain alkylamine and polyoxyethylene long-chain alkylamine will sometimes be uniformly referred to as "(poly)oxyethylene long-chain alkylamine".

[0075] As a (poly)oxyethylene long-chain alkylamine, the compound represented by the following general formula (c) is preferred.

[0076] [Chemical Formula 1]

[0077]

[0078] In general formula (c), R is a long-chain alkyl group. Furthermore, m and n are each independently an integer of 1 or more, preferably 2 or more, more preferably 5 or more. Furthermore, m and n are each independently preferably 15 or less, more preferably 12 or less, and particularly preferably 10 or less. Therefore, it is easy to satisfy the sum of the values ​​of m and n described below.

[0079] In general formula (c), the sum of the values ​​of m and n is an integer of 2 or more. The lower limit of the sum of the values ​​of m and n is preferably 4 or more, more preferably 8 or more, and particularly preferably 12 or more. The upper limit of the sum of the values ​​of m and n is preferably 30 or less, more preferably 24 or less, particularly preferably 20 or less, and even more preferably 15 or less. By keeping the sum of the values ​​of m and n within the above range, the long-chain alkylamine (C) easily segregates together with the above-mentioned rust inhibitor (B) on the surface of the adhesive layer, and the rust inhibitor (B) is easily and stably present on the surface.

[0080] The weight-average molecular weight of the long-chain alkylamine (C) is preferably 250 or more, particularly preferably 350 or more, especially preferably 500 or more, and even more preferably 700 or more. Furthermore, the weight-average molecular weight of the long-chain alkylamine (C) is preferably 1400 or less, more preferably 1300 or less, particularly preferably 1200 or less, and even more preferably 1000 or less. By ensuring that the weight-average molecular weight of the long-chain alkylamine (C) is within the above-mentioned range, the long-chain alkylamine (C) readily segregates together with the aforementioned rust inhibitor (B) on the surface of the adhesive layer, enabling the rust inhibitor (B) to exist stably on the surface and resulting in a superior anti-migration effect.

[0081] Relative to 100 parts by weight of the (meth)acrylate polymer (A), the content of long-chain alkylamine (C) in the adhesive composition P is preferably 0.01 parts by weight or more, more preferably 0.08 parts by weight or more, particularly preferably 0.12 parts by weight or more, and even more preferably 0.15 parts by weight or more. This allows the long-chain alkylamine (C) to easily segregate together with the aforementioned rust inhibitor (B) on the surface of the adhesive layer, making the rust inhibitor (B) easily and stably present on the surface, resulting in a superior anti-migration effect. Furthermore, the aforementioned content is preferably 2 parts by weight or less, more preferably 1 part by weight or less, particularly preferably 0.5 parts by weight or less, and even more preferably 0.2 parts by weight or less. Thus, in the surface of the obtained adhesive layer, the long-chain alkylamine (C) and the rust inhibitor (B) appropriately coexist to exert a good anti-migration effect while maintaining good adhesion.

[0082] (1-4) Silane compounds (D)

[0083] By including a silane compound (D) with alkoxysilyl groups at both ends in the adhesive composition P of this embodiment, the mitigation effect is further improved. This is believed to be because the alkoxysilyl groups in the silane compound (D) inhibit the penetration of moisture into the electrode adjacent to the resulting adhesive layer.

[0084] The silane compound (D) is an organosilicon compound having alkoxysilyl groups at both ends, preferably a compound represented by the following general formula (I).

[0085] [Chemical Formula 2]

[0086]

[0087] R in the formula 1 R can be a divalent hydrocarbon group that can have a nitrogen atom; 2 ~R 7 Each is an alkyl group independently.

[0088] The above R 1 The number of carbon atoms in the divalent hydrocarbon group is preferably 1 to 10, particularly preferably 3 to 9, further preferably 4 to 8, and most preferably 5 to 7 from the perspective of preventing migration of the metal electrode (especially the silver electrode). Furthermore, the hydrocarbon group is preferably a saturated hydrocarbon group, particularly preferably a chain-type saturated hydrocarbon group. Further, the hydrocarbon group preferably contains an alkylene group, particularly preferably an alkylene group. The number of carbon atoms in this alkylene group is preferably 1 to 10, particularly preferably 3 to 9, further preferably 4 to 8, and most preferably 5 to 7 from the perspective of preventing migration of the metal electrode (especially the silver electrode).

[0089] The above R 1When a nitrogen atom is present, the nitrogen atom can be present in the side chain of the aforementioned hydrocarbon group, but preferably in the main chain of the aforementioned hydrocarbon group. When the aforementioned R... 1 When it has a nitrogen atom, R 1 The number of nitrogen atoms contained therein is preferably 1 to 5, and particularly preferably 2 to 3. The nitrogen atoms are preferably amino or amide groups, particularly preferably amino, and even more preferably exist as secondary or tertiary amines in the main chain of the hydrocarbon group.

[0090] When the above R 1 When it has a nitrogen atom, R 1 Preferably containing -(CH) m The -NH- skeleton, more preferably containing -(CH) m -NH-(CH) n The skeleton of - is particularly preferred, containing -(CH) m -NH-(CH) n The -NH- skeleton is further preferably composed of -(CH). m -NH-(CH) n -NH-(CH) p - The skeleton. The above m, n, and p are positive integers, preferably 1 to 5, and particularly preferably 2 to 4.

[0091] The above R 1 Preferably, the main chain does not contain sulfur atoms. If sulfur atoms are present in the main chain, metal sulfides are easily formed at the interface between the adhesive and the electrode made of metal (especially silver) or metal oxide (especially ITO) in a durability test environment. This may hinder the aforementioned anti-migration effect.

[0092] The above R 2 ~R 7 The alkyl group preferably has 1 to 6 carbon atoms, particularly preferably 1 to 4, further preferably 1 to 2, and most preferably 1. Furthermore, the above-mentioned R... 2 ~R 7 All are the same alkyl group, and the most preferred group is methyl.

[0093] The lower limit of the content of silane compound (D) in the adhesive composition P relative to 100 parts by weight of (meth)acrylate polymer (A) is preferably 0.01 parts by weight or more, more preferably 0.1 parts by weight or more, particularly preferably 0.16 parts by weight or more, and even more preferably 0.22 parts by weight or more. Furthermore, the upper limit of this content is preferably 2 parts by weight or less, particularly preferably 1 part by weight or less, and even more preferably 0.5 parts by weight or less. By keeping the content of silane compound (D) within the above-mentioned range, the effects of silane compound (D) can be effectively exerted, resulting in a superior mitigation effect.

[0094] (1-5) Alkyl glycols (E)

[0095] By including alkylene glycol (E) in the adhesive composition P of this embodiment, the mitigation effect is further enhanced. This is believed to be because the hydroxyl groups present in the alkylene glycol (E) inhibit the penetration of moisture into the electrode adjacent to the resulting adhesive layer.

[0096] As for alkylene glycols (E), there are no particular limitations as long as they can achieve the above-mentioned effects. In addition to ethylene glycol, propylene glycol, butanediol, glycerol, etc., alkylene glycol monoalkyl ethers are also preferred. Among them, alkylene glycol monoalkyl ethers have particularly excellent anti-migration effects.

[0097] The alkylene group of the alkylene glycol in the alkylene glycol monoalkyl ether preferably has 1 or more carbon atoms, more preferably 2 or more, and particularly preferably 3 or more. Furthermore, the number of carbon atoms in the alkylene group is preferably 10 or less, more preferably 8 or less, and particularly preferably 6 or less. On the other hand, the number of carbon atoms in the monoalkyl ether of the alkylene glycol monoalkyl ether is preferably 1 or more. Furthermore, the number of carbon atoms in the alkyl group is preferably 8 or less, more preferably 6 or less, particularly preferably 4 or less, and even more preferably 3 or less.

[0098] Specifically, examples of alkylene glycol monoalkyl ethers include ethylene glycol monomethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, polyethylene glycol monomethyl ether, polyethylene glycol monopropyl ether, polyethylene glycol monobutyl ether, etc., which are ethylene glycol monoalkyl ethers; and propylene glycol monoalkyl ethers include propylene glycol monomethyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monobutyl ether, polypropylene glycol monomethyl ether, polypropylene glycol monobutyl ether, etc., which are propylene glycol monoalkyl ethers. Propylene glycol monoalkyl ethers are preferred, dipropylene glycol monoalkyl ethers are particularly preferred, and dipropylene glycol monomethyl ethers are even more preferred. Alkylene glycol (E) can be used alone or in combination with two or more other alcohols.

[0099] The lower limit of the alkylene glycol (E) content in the adhesive composition P relative to 100 parts by weight of (meth)acrylate polymer (A) is preferably 0.01 parts by weight or more, more preferably 0.1 parts by weight or more, particularly preferably 0.4 parts by weight or more, and even more preferably 0.8 parts by weight or more. Furthermore, the upper limit of this content is preferably 5 parts by weight or less, more preferably 3 parts by weight or less, particularly preferably 2 parts by weight or less, and even more preferably 1.5 parts by weight or less. By keeping the alkylene glycol (E) content within the above-mentioned range, the effects of the alkylene glycol (E) can be effectively utilized, resulting in a superior mitigation effect.

[0100] (1-6) Crosslinking agent (F)

[0101] The adhesive composition P preferably contains a crosslinking agent (F). By including the crosslinking agent (F) in the adhesive composition P, the (meth)acrylate polymer (A) is crosslinked to form a three-dimensional network structure, which can improve the cohesiveness and durability of the resulting adhesive.

[0102] As the crosslinking agent (F), any crosslinking agent that reacts with the reactive groups present in the (meth)acrylate polymer (A) can be used. Examples include isocyanate crosslinking agents, epoxy crosslinking agents, amine crosslinking agents, 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, and ammonium salt crosslinking agents. When the (meth)acrylate polymer (A) contains hydroxyl-containing monomers as monomer units constituting the polymer, isocyanate crosslinking agents with excellent reactivity with their hydroxyl groups are preferred. Furthermore, crosslinking agent (F) can be used alone or in combination of two or more.

[0103] Isocyanate crosslinking agents contain at least a polyisocyanate compound. Examples of polyisocyanate compounds include aromatic polyisocyanates such as toluene diisocyanate, diphenylmethane diisocyanate, and phenylene diisocyanate; aliphatic polyisocyanates such as hexamethylene diisocyanate; alicyclic polyisocyanates such as isophorone diisocyanate and hydrogenated diphenylmethane diisocyanate; their biuret forms, isocyanurate forms, and adducts as reactants with low-molecular-weight compounds containing active hydrogen, such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, and castor oil. From the perspective of reactivity with hydroxyl groups, trimethylolpropane-modified aromatic polyisocyanates are preferred, and trimethylolpropane-modified toluene diisocyanate is particularly preferred.

[0104] The lower limit of the crosslinking agent (F) content in the adhesive composition P relative to 100 parts by weight of (meth)acrylate polymer (A) is preferably 0.001 parts by weight or more, particularly preferably 0.01 parts by weight or more, and even more preferably 0.1 parts by weight or more. From the perspective of easily and appropriately segregating the rust inhibitor (B) and long-chain alkylamine (C) to the surface of the adhesive layer, it is preferably 0.3 parts by weight or more, particularly preferably 0.6 parts by weight or more. Furthermore, the upper limit of the above content is preferably 10 parts by weight or less, particularly preferably 5 parts by weight or less, and even more preferably 1 part by weight or less. From the perspective of improving adhesion, it is preferably 0.5 parts by weight or less. By keeping the crosslinking agent (F) content within the above range, the cohesive strength of the resulting adhesive is preferred, and an adhesive with even better adhesion can be obtained.

[0105] (1-7) Active energy ray curing component (G)

[0106] When the adhesive obtained from the adhesive composition P of this embodiment is used as an active energy radiation-curable adhesive, the adhesive composition P preferably contains an active energy radiation-curable component (G). An adhesive obtained by crosslinking (thermal crosslinking) the adhesive composition P by including the active energy radiation-curable component (G) in the adhesive composition P becomes an active energy radiation-curable adhesive. It is speculated that in this active energy radiation-curable adhesive, through curing based on active energy radiation irradiation after adhesion to the adhered object, the active energy radiation-curable component (G) polymerizes with each other, and the polymerized active energy radiation-curable component (G) becomes entangled in the crosslinked structure (three-dimensional network structure) of the (meth)acrylate polymer (A). Adhesives with this high-dimensional structure have high cohesiveness and exhibit high coating strength, thus exhibiting superior durability.

[0107] The active energy ray curable component (G) is not particularly limited as long as it is a component that can be cured by irradiation with active energy rays and achieve the above-mentioned effect. It can be any one of monomers, oligomers, or polymers, or a mixture of these substances. Among them, multifunctional acrylate monomers that can produce adhesives with better durability are preferably listed.

[0108] Examples of multifunctional acrylate monomers include 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, neopentyl adipate di(meth)acrylate, neopentyl hydroxypentyl adipate di(meth)acrylate, dicyclopentyl di(meth)acrylate, caprolactone-modified dicyclopentenyl di(meth)acrylate, ethylene oxide-modified di(meth)acrylate phosphate, di(acryloyloxyethyl)isocyanurate, allylated cyclohexyl di(meth)acrylate, ethoxylated bisphenol A diacrylate, and 9,9-bis[4-(2-acryloyloxyethoxy)phenyl]fluorene. Difunctional types include: trimethylolpropane tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, propionic acid-modified dipentaerythritol tri(meth)acrylate, pentaerythritol tri(meth)acrylate, propylene oxide-modified trimethylolpropane tri(meth)acrylate, tri(acryloyloxyethyl)isocyanurate, ε-caprolactone-modified tri(2-(meth)acryloyloxyethyl)isocyanurate, etc.; tetrafunctional types include diglycerol tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, etc.; pentafunctional types include propionic acid-modified dipentaerythritol penta(meth)acrylate, etc.; and hexafunctional types include dipentaerythritol hexa(meth)acrylate, caprolactone-modified dipentaerythritol hexa(meth)acrylate, etc. Among the above, from the perspective of imparting suitable cohesiveness and adhesion to the obtained adhesive and effectively suppressing undesirable conditions such as lifting or peeling at the interface with the adhered object, polyfunctional acrylate monomers containing an isocyanurate structure within the molecule, such as di(acryloyloxyethyl)isocyanurate, tri(acryloyloxyethyl)isocyanurate, and ε-caprolactone-modified tri(2-(meth)acryloyloxyethyl)isocyanurate, are preferred. Polyfunctional acrylate monomers with trifunctionality or higher and containing an isocyanurate structure within the molecule are more preferred, and ε-caprolactone-modified tri(2-(meth)acryloyloxyethyl)isocyanurate is particularly preferred. These polyfunctional acrylate monomers can be used alone or in combination of two or more. Furthermore, from the perspective of compatibility with the (meth)acrylate polymer (A), the molecular weight of the polyfunctional acrylate monomer is preferably less than 1000.

[0109] As the active energy ray curable component (G), active energy ray curable acrylate oligomers can also be used. Examples of such acrylate oligomers include polyester acrylates, epoxy acrylates, urethane acrylates, polyether acrylates, polybutadiene acrylates, and silicone acrylates.

[0110] The weight-average molecular weight of the above-mentioned acrylate oligomers is preferably 50,000 or less, particularly preferably 1,000 to 50,000, and even more preferably 3,000 to 40,000. These acrylate oligomers can be used alone or in combination of two or more.

[0111] Furthermore, as the active energy ray curable component (G), an addition acrylate polymer with (meth)acryloyl groups introduced into its side chain can also be used. Such an addition acrylate polymer can be obtained by using a copolymer of (meth)acrylate and a monomer having a crosslinking functional group within the molecule, and reacting a compound having a (meth)acryloyl group and a group that reacts with the crosslinking functional group with a portion of the crosslinking functional group of the copolymer.

[0112] The weight-average molecular weight of the above-mentioned addition acrylate polymers is preferably around 50,000 to 900,000, and particularly preferably around 100,000 to 500,000.

[0113] The active energy ray curing component (G) can be selected from one of the above-mentioned multifunctional acrylate monomers, acrylate oligomers and addition acrylate polymers, or two or more can be used in combination, or it can be used in combination with other active energy ray curing components.

[0114] When the adhesive composition P contains an active energy ray curable component (G), the content of the active energy ray curable component (G) relative to 100 parts by weight of the (meth)acrylate polymer (A) is preferably 2 parts by weight or more, more preferably 3 parts by weight or more, and particularly preferably 4 parts by weight or more. Furthermore, the above-mentioned content is preferably 20 parts by weight or less, more preferably 10 parts by weight or less, particularly preferably 8 parts by weight or less, and even more preferably 6 parts by weight or less. By keeping the content of the active energy ray curable component (G) within the above range, the adhesion of the adhesive after active energy ray curing can be improved, and the durability of the adhesive can also be made more excellent.

[0115] (1-8) Photopolymerization initiator (H)

[0116] When the adhesive obtained from the adhesive composition P of this embodiment is used as an active energy ray curable adhesive, it is preferable that the adhesive composition P further contains a photopolymerization initiator (H) when using ultraviolet light as the active energy ray. By containing the photopolymerization initiator (H) in this way, the active energy ray curable component (G) can be polymerized effectively, and the polymerization curing time and the amount of active energy ray irradiation can be reduced.

[0117] Examples of photopolymerization initiators (H) include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropane-1-one, 1-hydroxycyclohexylphenyl one, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinyl-propane-1-one, and 4-(2-hydroxyethoxy)phenyl-2-(hydroxy-2-propyl) Ketones, benzophenone, p-phenylbenzophenone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyl dimethyl ketal, acetophenone dimethyl ketal, p-dimethylaminobenzoate, oligomer [2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]acetone], 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, etc. These photopolymerization initiators can be used alone or in combination of two or more.

[0118] When the adhesive composition P contains an active energy ray curable component (G) and a photopolymerization initiator (H), the lower limit of the content of the photopolymerization initiator (H) relative to 100 parts by mass of the active energy ray curable component (G) is preferably 0.1 parts by mass or more, particularly preferably 1 part by mass or more, and even more preferably 5 parts by mass or more. Furthermore, the upper limit of the above content is preferably 30 parts by mass or less, particularly preferably 20 parts by mass or less, and even more preferably 15 parts by mass or less. By keeping the content of the photopolymerization initiator (H) within the above range, the adhesion of the adhesive after active energy ray curing can be improved, and the durability of the adhesive can also be made more excellent.

[0119] (1-9) Various additives

[0120] Various additives commonly used in acrylic adhesives, such as UV absorbers, silane coupling agents, antistatic agents, tackifiers, antioxidants, light stabilizers, softeners, fillers, and refractive index modifiers, can be added to the adhesive composition P as needed.

[0121] Examples of ultraviolet absorbers include benzophenones, benzotriazoles, benzoic acid esters, benzoxazinones, triazines, phenyl salicylate esters, cyanoacrylates, and nickel complex salts. Among these, at least one of benzophenones, benzotriazoles, and triazines is preferred.

[0122] Examples of the aforementioned benzophenone compounds include 2,2-dihydroxy-4-methoxybenzophenone, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid hydrate, and 2-hydroxy-4-n-octyloxybenzophenone, among which 2,2-dihydroxy-4-methoxybenzophenone is preferred.

[0123] Examples of the aforementioned benzotriazole compounds include 2-(2-hydroxy-5-tert-butylphenyl)-2H-benzotriazole, octyl-3-[3-tert-butyl-4-hydroxy-5-(5-chloro-2H-benzotriazole-2-yl)phenyl]propionate, 2-ethylhexyl-3-[3-tert-butyl-4-hydroxy-5-(5-chloro-2H-benzotriazole-2-yl]phenyl]propionate, and 3-(2H-benzotriazole-2-yl)-5-(1,1-dimethylethyl)-4-hydroxyphenylpropionic acid.

[0124] Examples of the aforementioned triazine compounds include 2,4-bis[2-hydroxy-4-butoxyphenyl]-6-(2,4-dibutoxyphenyl)-1,3-5-triazine and 2-[4,6-bis(2,4-dimethylyl)-1,3,5-triazine-2-yl]-5-octyloxyphenol.

[0125] The above ultraviolet absorbers can be used alone or in combination of two or more.

[0126] When the adhesive composition P contains a UV absorber, the content of the UV absorber relative to 100 parts by weight of the (meth)acrylate polymer (A) is preferably 0.1 parts by weight or more, particularly preferably 0.5 parts by weight or more, and even more preferably 1.0 parts by weight or more. Furthermore, the above-mentioned content is preferably 15 parts by weight or less, more preferably 12 parts by weight or less, particularly preferably 8 parts by weight or less, and even more preferably 4 parts by weight or less. By keeping the content of the UV absorber within the above range, the adhesive layer readily exhibits good UV absorption properties.

[0127] In addition, the adhesive composition P refers to a mixture of various components that remain in the adhesive layer directly or in a reacted state. Components that are removed in the drying process or the like, such as the polymerization solvent or diluting solvent described below, are not included in the adhesive composition P.

[0128] (2) Preparation of adhesive composition

[0129] The adhesive composition P can be prepared by preparing a (meth)acrylate polymer (A), mixing the obtained (meth)acrylate polymer (A), rust inhibitor (B), long-chain alkylamine (C), and adding silane compound (D), alkylene glycol (E), crosslinking agent (F), active energy radiation curing component (G), photopolymerization initiator (H), additives, etc. as needed.

[0130] (Meth)acrylate polymer (A) can be prepared by polymerizing a mixture of monomer units constituting the polymer using conventional free radical polymerization. The polymerization of (meth)acrylate polymer (A) can be carried out using a polymerization initiator and by solution polymerization or other methods, as needed. Examples of polymerization solvents include ethyl acetate, n-butyl acetate, isobutyl acetate, toluene, acetone, hexane, and methyl ethyl ketone; two or more solvents may also be used simultaneously.

[0131] Examples of polymerization initiators include azo compounds and organic peroxides, and more than one type can be used simultaneously. Examples of azo compounds include 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 1,1'-azobis(cyclohexane-1-carboxylonitrile), 2,2'-azobis(2,4-dimethylpentanonitrile), 2,2'-azobis(2,4-dimethyl-4-methoxypentanonitrile), 2,2'-azobis(2-methylpropionic acid) dimethyl ester, 4,4'-azobis(4-cyanopentanoic acid), 2,2'-azobis(2-hydroxymethylpropionitrile), and 2,2'-azobis[2-(2-imidazolin-2-yl)propane].

[0132] Examples of organic peroxides include benzoyl peroxide, tert-butyl peroxide, cumene hydroperoxide, diisopropyl peroxide, di-n-propyl peroxide, di(2-ethoxyethyl) peroxide, tert-butyl peroxynedecanoate, tert-butyl peroxynepentanoate, (3,5,5-trimethylhexanoyl peroxide), dipropionyl peroxide, and diacetyl peroxide.

[0133] Furthermore, in the above polymerization process, the weight-average molecular weight of the obtained polymer can be adjusted by incorporating chain transfer agents such as 2-mercaptoethanol.

[0134] After obtaining (meth)acrylate polymer (A), a rust inhibitor (B), a long-chain alkylamine (C), and, as needed, a silane compound (D), an alkylene glycol (E), a crosslinking agent (F), an active energy radiation curable component (G), a photopolymerization initiator (H), additives, a diluent, etc., are added to the solution of (meth)acrylate polymer (A) and mixed thoroughly to obtain an adhesive composition P (coating solution) diluted with solvent.

[0135] As diluents for the above-mentioned purposes, aliphatic hydrocarbons such as hexane, heptane, and cyclohexane; aromatic hydrocarbons such as toluene and xylene; halogenated hydrocarbons such as dichloromethane and dichloroethane; alcohols such as methanol, ethanol, propanol, butanol, and 1-methoxy-2-propanol; ketones such as acetone, methyl ethyl ketone, 2-pentanone, isophorone, and cyclohexanone; esters such as ethyl acetate and butyl acetate; and cellosol solvents such as ethyl cellosol.

[0136] The concentration and viscosity of the coating solution prepared in this manner are not particularly limited, as long as they fall within the coating range, and can be appropriately selected according to the situation. For example, the adhesive composition P can be diluted to a concentration of 10-40% by mass. Furthermore, adding a diluent is not necessary when obtaining the coating solution; if the adhesive composition P has a coatable viscosity, a diluent may not be added. In this case, the adhesive composition P is a coating solution in which the polymerization solvent of the (meth)acrylate polymer (A) is used directly as the diluent.

[0137] [Adhesive]

[0138] The adhesive in this embodiment is formed by crosslinking the above-described adhesive composition P. The crosslinking of the adhesive composition P can be performed by heat treatment. Alternatively, the drying process, in which the diluent or other solvents of the coated adhesive composition P evaporate, can also be used as this heat treatment.

[0139] During heat treatment, the heating temperature is preferably 50–150°C, and particularly preferably 70–120°C. Furthermore, the heating time is preferably 30 seconds–10 minutes, and particularly preferably 50 seconds–2 minutes. After heat treatment, a curing period of approximately 1–2 weeks at room temperature (e.g., 23°C, 50% RH) may be set as needed. If this curing period is required, an adhesive layer will form after the curing period; otherwise, the adhesive layer will form immediately after the heat treatment is completed.

[0140] The lower limit of the gel fraction of the adhesive in this embodiment is preferably 30% or more, particularly preferably 40% or more, and even more preferably 45% or more. If the lower limit of the gel fraction of the adhesive is as described above, the cohesive strength is improved, and the durability becomes higher. Furthermore, the upper limit of the gel fraction is preferably 90% or less, more preferably 80% or less, particularly preferably 75% or less, and from the perspective of further improving adhesion, preferably 65% ​​or less, and even more preferably 55% or less. If the upper limit of the gel fraction of the adhesive is as described above, the adhesive will not become too hard, and the adhesion becomes higher. In addition, the rust inhibitor (B) and the long-chain alkylamine (C) readily and appropriately segregate to the surface of the adhesive layer. The method for determining the gel fraction of this adhesive is shown in the experimental examples described below.

[0141] [Adhesive sheet]

[0142] like Figure 1 As shown, the adhesive sheet 1 of this embodiment consists of two release tabs 12a and 12b and an adhesive layer 11, which is held by the release tabs 12a and 12b in contact with their release surfaces. However, in the adhesive sheet 1, the release tabs 12a and 12b are not essential components and are peeled off and removed when the adhesive sheet 1 is used. Furthermore, the release surface of the release tab in this specification refers to the surface of the release tab that has release properties, including either the surface that has undergone release treatment or the surface that exhibits release properties even without release treatment.

[0143] (1)Adhesive layer

[0144] The adhesive layer 11 is composed of the adhesive described above. The lower limit of the thickness of the adhesive layer 11 (a value measured according to JIS K 7130) is preferably 5 μm or more, more preferably 10 μm or more, particularly preferably 25 μm or more, and even more preferably 45 μm or more. By setting the lower limit of the thickness of the adhesive layer 11 to the above-mentioned value, excellent adhesion can be fully utilized. Furthermore, the upper limit of the thickness of the adhesive layer 11 is preferably 300 μm or less, more preferably 200 μm or less, particularly preferably 100 μm or less, and even more preferably 70 μm or less. By setting the upper limit of the thickness of the adhesive layer 11 to the above-mentioned value, processability becomes good. In addition, the rust inhibitor (B) and the long-chain alkylamine (C) readily and appropriately segregate to the surface of the adhesive layer. Furthermore, the adhesive layer 11 can be formed as a single layer or as multiple layers stacked together.

[0145] (2) Peeling sheet

[0146] As release sheets 12a and 12b, there are no particular limitations, and known plastic films 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)acrylate copolymer film, ethylene-(meth)acrylate copolymer film, polystyrene film, polycarbonate film, polyimide film, fluoropolymer film, etc., can also be used. Furthermore, laminated films of these films can also be used.

[0147] It is preferable to perform a peeling treatment on the peeling surfaces (particularly the surfaces in contact with the adhesive layer 11) of the aforementioned release sheets 12a and 12b. Examples of release agents used for the peeling treatment include alkyd, silicone, fluorinated, unsaturated polyester, polyolefin, and wax-based release agents. Furthermore, among the release sheets 12a and 12b, it is preferable to designate one release sheet as a heavy-duty release sheet with high peeling force and the other as a light-duty release sheet with low peeling force.

[0148] There are no particular restrictions on the thickness of the release strips 12a and 12b, but they are usually around 20 to 150 μm.

[0149] (3) Manufacturing of adhesive sheets

[0150] As an example of manufacturing the adhesive sheet 1, a coating liquid of the adhesive composition P is applied to the release surface of a release sheet 12a (or 12b), and after heat treatment to crosslink the adhesive composition P and form a coating layer, the release surface of another release sheet 12b (or 12a) is laminated onto the coating layer. If a curing period is required, the coating layer becomes the adhesive layer 11 by setting a curing period; if no curing period is required, the coating layer directly becomes the adhesive layer 11. Thus, the adhesive sheet 1 is obtained. The heat treatment and curing conditions are as described above.

[0151] As another manufacturing example of the adhesive sheet 1, a coating liquid of the adhesive composition P is applied to the release surface of a release sheet 12a, and then heated to crosslink the adhesive composition P and form a coating layer, resulting in a release sheet 12a with a coating layer. Furthermore, a coating liquid of the adhesive composition P is applied to the release surface of another release sheet 12b, and then heated to crosslink the adhesive composition P and form a coating layer, resulting in a release sheet 12b with a coating layer. 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. If a curing period is required, the laminated coating layers become the adhesive layer 11 by setting a curing period; if a curing period is not required, the laminated coating layers directly become the adhesive layer 11. Thus, the adhesive sheet 1 is obtained. According to this manufacturing example, even if the adhesive layer 11 is relatively thick, manufacturing can be carried out stably.

[0152] Methods for applying the coating liquid to the adhesive composition P include, for example, bar coating, blade coating, roller coating, squeegee coating, die coating, gravure coating, etc.

[0153] (4) Physical properties of the adhesive sheet

[0154] (4-1) Adhesion

[0155] The lower limit of the adhesion force of the adhesive sheet 1 to the soda-lime glass in this embodiment is preferably 10 N / 25 mm or more, particularly preferably 15 N / 25 mm or more, and even more preferably 20 N / 25 mm or more. If the lower limit of the adhesion force is as described above, the durability of the adhesive layer 11 becomes even better. Furthermore, the upper limit of the adhesion force is preferably 100 N / 25 mm or less, more preferably 80 N / 25 mm or less, particularly preferably 60 N / 25 mm or less, and even more preferably 45 N / 25 mm or less. If the upper limit of the adhesion force is as described above, good reoperability can be obtained, allowing for re-adhesion even in the event of an adhesion error.

[0156] The aforementioned adhesion refers to the adhesion measured essentially by the 180-degree peel method according to JIS Z0237:2009. The method involves preparing a test sample 25 mm wide and 100 mm long, attaching the test sample to the object to be adhered to, applying pressure of 0.5 MPa and 50°C for 20 minutes, placing it under normal pressure, 23°C, and 50% RH conditions for 24 hours, and then measuring the value at a peeling speed of 300 mm / min.

[0157] (4-2) Haze value

[0158] In this embodiment, the haze value of the adhesive layer 11 of the adhesive sheet 1 is preferably 1% or less, more preferably 0.5% or less, particularly preferably 0.3% or less, and even more preferably 0.2% or less. By achieving the haze value of the adhesive layer 11 as described above, excellent light transmittance is achieved, making it suitable for use in displays. The lower limit of the haze value is not particularly limited, but is preferably 0% or more, more preferably 0.01% or more.

[0159] Furthermore, the haze values ​​described above encompass the characteristics of the adhesive layer thickness, and preferably, the haze values ​​are satisfied regardless of the adhesive layer thickness. Here, the haze values ​​in this specification are values ​​measured according to JIS K7136:2000.

[0160] (4-3) Total transmittance

[0161] In this embodiment, the total light transmittance of the adhesive layer 11 of the adhesive sheet 1 is preferably 70% or more, more preferably 80% or more, particularly preferably 90% or more, further preferably 95% or more, and most preferably 99% or more. By achieving the above-mentioned total light transmittance of the adhesive layer 11, excellent light transmittance is achieved, making it suitable for use in displays. The upper limit of the above-mentioned total light transmittance is typically 100%. Furthermore, the total light transmittance in this specification is a value measured according to JIS K7361-1:1997.

[0162] (4-4) CIE1976 L*a*b* color system

[0163] The absolute value of the chromaticity a* of the adhesive layer 11 of the adhesive sheet 1 in this embodiment, as defined by the CIE 1976 L*a*b* color system, is preferably 0 or more, particularly preferably 0.1 or more. Furthermore, the absolute value of this chromaticity a* is preferably 0.8 or less, particularly preferably 0.6 or less, and even more preferably 0.4 or less. The absolute value of the chromaticity b* of the adhesive layer 11 is preferably 0 or more, particularly preferably 0.1 or more. Furthermore, the absolute value of this chromaticity b* is preferably 0.8 or less, particularly preferably 0.6 or less, and even more preferably 0.4 or less. Based on the above, the adhesive layer 11 has a suitable hue for use as a display. In addition, the methods for measuring the lightness L*, chromaticity a*, and b* in this specification are shown in the test examples described later.

[0164] [Display Body]

[0165] The display body of this embodiment includes a first display body component, a second display body component, and an adhesive layer for bonding the first display body component and the second display body component together. The adhesive layer is composed of the adhesive described in this embodiment. Here, the first display body component and / or the second display body component have electrodes made of metal or metal oxide on at least one side of the surface to which they are bonded (adhesive layer side). As a preferred structure, the second display body component has the aforementioned electrodes on at least one side of the surface to which it is bonded.

[0166] Examples of display devices include liquid crystal displays (LCDs), light-emitting diode (LED) displays, organic electroluminescent (OLED) displays, and electronic paper; touch panels are also possible. Furthermore, a display device can also be a component that forms part of them.

[0167] Both the first and second display body components can be rigid, non-flexible materials. Based on the adhesive layer obtained from the adhesive composition P described above, the rigid first and second display body components can be bonded together without any problems.

[0168] Besides glass plates and plastic plates, the first display body component is preferably a protective panel composed of a laminate containing glass plates, plastic plates, etc. The first display body component may have a step on the surface of the adhesive layer side. Specifically, it is preferable to have a step based on a printed layer. This printed layer is typically formed in a frame shape.

[0169] The glass plate mentioned above is not particularly limited, and examples include chemically strengthened glass, alkali-free glass, quartz glass, soda-lime glass, barium-strontium glass, aluminosilicate glass, lead glass, borosilicate glass, and barium borosilicate glass. The thickness of the glass plate is not particularly limited, but is typically 0.1–5 mm, preferably 0.2–2 mm.

[0170] The plastic sheet used is not particularly limited; examples include acrylic sheets and polycarbonate sheets. The thickness of the plastic sheet is not particularly limited, but is typically 0.2–5 mm, preferably 0.4–3 mm.

[0171] In addition, various functional layers (electrode layers, silicon dioxide layers, hard coatings, anti-glare layers, etc.) can be set on one or both sides of the glass or plastic plate, and optical components can also be stacked.

[0172] The material constituting the printing layer is not particularly limited, and known printing materials can be used. The lower limit of the thickness of the printing layer, i.e., 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. By setting the lower limit to the above-mentioned value, sufficient concealment of electrical wiring, etc., from the observer's side can be ensured. Furthermore, the upper limit is preferably 50 μm or less, more preferably 35 μm or less, particularly preferably 25 μm or less, and even more preferably 20 μm or less. By setting the upper limit to the above-mentioned value or less, the adhesion of the adhesive layer to the step of the printing layer can be prevented from deteriorating.

[0173] The second display component is preferably an optical component, a display module (e.g., a liquid crystal (LCD) module, a light-emitting diode (LED) module, an organic electroluminescent (organic EL) module, etc.) that should be attached to the first display component, an optical component that is part of the display module, or a laminate containing the display module, having electrodes made of metal or metal oxide on at least the surface on the adhesive layer side.

[0174] Examples of such optical components include film sensors, electrode films, metal nanowire films, and wiregrid polarizing films.

[0175] Examples of metal electrodes include metal wiring (including mesh, grid, and nanowire types) made of silver, silver alloys, copper, or copper alloys. Metal wiring constituting electrodes for touch panels is particularly preferred; more specifically, metal wiring contained in membrane sensors is preferred. Among these metal wirings, those made of silver or silver alloy nanoparticles are preferred; and silver alloys formed by adding palladium and copper to silver are particularly preferred. These metal wirings readily utilize the excellent anti-migration effect provided by the adhesive layer 11.

[0176] Examples of electrodes made of metal oxides include those patterned from transparent conductive films made of metal oxides such as tin-doped indium oxide (ITO) and zinc oxide. Among these, electrodes patterned from transparent conductive films made of ITO are particularly preferred, as the adhesive layer 11 readily provides excellent anti-migration effects for the ITO transparent conductive film.

[0177] The wiring width of the positive and negative electrodes in the electrodes made of the aforementioned metals or metal oxides is preferably 100 μm or less, more preferably 60 μm or less, particularly preferably 45 μm or less, and even more preferably 35 μm or less. Furthermore, this wiring width is preferably 10 μm or more, more preferably 15 μm or more, particularly preferably 20 μm or more, and even more preferably 25 μm or more. If the wiring width is within the above range, it contributes to the miniaturization and narrowing of the electrode spacing. Simultaneously, the adhesive layer of this embodiment exhibits excellent anti-migration effects, thus contributing to improved electrode connection reliability.

[0178] The distance between the wirings of the positive and negative electrodes in the electrode made of the aforementioned metal or metal oxide is preferably 100 μm or less, more preferably 60 μm or less, particularly preferably 45 μm or less, and even more preferably 35 μm or less. Furthermore, this wiring distance is preferably 10 μm or more, more preferably 15 μm or more, particularly preferably 20 μm or more, and even more preferably 25 μm or more. If the wiring distance is within the above range, it contributes to the miniaturization and narrowing of the electrode spacing. Simultaneously, the adhesive layer of this embodiment exhibits excellent anti-migration effects, thus contributing to improved electrode connection reliability.

[0179] As an example of the display entity in this implementation scheme, Figure 2 The image shows an electrostatic capacitive touch panel 2. The touch panel 2 comprises a display module 3, a first film sensor 5a laminated on the display module 3 via an adhesive layer 4, a second film sensor 5b laminated on the first film sensor 5a via a first adhesive layer 11, and a cover material 6 laminated on the second film sensor 5b via a second adhesive layer 11. A printed layer 7 is formed on the surface of the cover material 6 on the side of the second adhesive layer 11, thus creating a step difference due to the presence or absence of the printed layer 7. In this embodiment, the cover material 6 corresponds to the first display component, and the second film sensor 5b corresponds to the second display component, or the second film sensor 5b corresponds to the first display component, and the first film sensor 5a corresponds to the second display component.

[0180] To prevent migration, it is preferable that both the first adhesive layer 11 and the second adhesive layer 11 in the touch panel 2 are adhesive layers 11 of the adhesive sheet 1. Alternatively, if the first adhesive layer 11 or the second adhesive layer 11 is not an adhesive layer 11 of the adhesive sheet 1, the adhesive constituting the adhesive layer can be an acrylic adhesive, a rubber adhesive, a silicone adhesive, a urethane adhesive, a polyester adhesive, a polyvinyl ether adhesive, etc., with acrylic adhesives being preferred.

[0181] The adhesive layer 4 can be formed from the adhesive layer 11 of the adhesive sheet 1, or it can be formed from other adhesives or adhesive sheets. In the latter case, examples of adhesives constituting the adhesive layer 4 include acrylic adhesives, rubber adhesives, silicone adhesives, urethane adhesives, polyester adhesives, and polyvinyl ether adhesives, among which acrylic adhesives are preferred.

[0182] In this embodiment, the first membrane sensor 5a and the second membrane sensor 5b each have a substrate membrane 51 and an electrode 52 formed on the substrate membrane 51. The substrate membrane 51 is not particularly limited; for example, a polyethylene terephthalate membrane, an acrylic membrane, or a polycarbonate membrane can be used.

[0183] Electrode 52 can be exemplified as shown above. Typically, one of the electrodes 52 of the first membrane sensor 5a and the second membrane sensor 5b forms a circuit pattern in the X-axis direction, and the other forms a circuit pattern in the Y-axis direction.

[0184] In this embodiment, the electrode 52 of the second membrane sensor 5b is located at... Figure 2 The electrode 52 of the first membrane sensor 5a is located above the second membrane sensor 5b. On the other hand, the electrode 52 of the first membrane sensor 5a is located... Figure 2 The sensor is located above the first membrane sensor 5a, but is not limited to this; it can also be located below the first membrane sensor 5a.

[0185] The following is an example of the manufacturing method of the above-mentioned touch panel 2.

[0186] As adhesive sheets 1, a first adhesive sheet 1 and a second adhesive sheet 1 are prepared. A release tab 12a is peeled off from the first adhesive sheet 1, and the exposed adhesive layer 11 (first adhesive layer) is bonded to the first membrane sensor 5a in such a way that it contacts the electrode 52 of the first membrane sensor 5a. Similarly, a release tab 12a is peeled off from the second adhesive sheet 1, and the exposed adhesive layer 11 (second adhesive layer 11) is bonded to the second membrane sensor 5b in such a way that it contacts the electrode 52 of the second membrane sensor 5b.

[0187] Then, another release tab 12b of the first adhesive tab 1 is peeled off, so that the exposed first adhesive layer 11 is brought into contact with the side of the second membrane sensor 5b opposite to the side where the second adhesive layer 11 is stacked (the exposed side of the substrate film 51 of the second membrane sensor 5b), thus bonding the two together. This results in a laminate consisting of the release tab 12b, the second adhesive layer 11, the second membrane sensor 5b, the first adhesive layer 11, and the first membrane sensor 5a, stacked sequentially.

[0188] Next, the adhesive layer 4 disposed on the release sheet is attached to the surface of the laminated body on the side of the first membrane sensor 5a (the exposed surface of the substrate film 51 of the first membrane sensor 5a). Then, the release sheet 12b is peeled off from the laminated body, and the exposed second adhesive layer 11 is attached to the cover material 6 so that the printed layer 7 side of the cover material 6 contacts the second adhesive layer 11. Through this attachment, a structure is obtained by sequentially stacking the cover material 6, the second adhesive layer 11, the second membrane sensor 5b, the first adhesive layer 11, the first membrane sensor 5a, the adhesive layer 4, and the release sheet.

[0189] Next, the release tab is peeled off from the structure so that the exposed adhesive layer 4 contacts the display module 3, and the structure is then attached to the display module 3. This completes the manufacturing process. Figure 2 The touch panel 2 shown.

[0190] Here, when the first adhesive layer 11 and / or the second adhesive layer 11 are composed of an active energy radiation-curable adhesive, the adhesive layer 11 in the aforementioned structure or touch panel 2 is irradiated with active energy radiation. As a result, the active energy radiation-curable component (G) in the adhesive layer 11 polymerizes, and the adhesive layer 11 cures to form a cured adhesive layer. The irradiation of the adhesive layer 11 with energy radiation is typically performed from one side of the aforementioned structure or touch panel 2, preferably from the side of the covering material 6.

[0191] Furthermore, active energy rays refer to active energy rays containing energy quanta within electromagnetic waves or charged particle beams; specifically, examples include ultraviolet light or electron beams. Among active energy rays, ultraviolet light, which is particularly easy to manipulate, is especially preferred.

[0192] Ultraviolet (UV) irradiation can be achieved using high-pressure mercury lamps, fusion H lamps, xenon lamps, etc. The optimal UV irradiation intensity is 50–1000 mW / cm². 2 The preferred value is 100–600 mW / cm². 2 Furthermore, the preferred light intensity is 50–10000 mJ / cm². 2 More preferably 80–5000 mJ / cm 2 The preferred value is 200–2000 mJ / cm³.2 On the other hand, electron beam irradiation can be performed using an electron beam accelerator or the like, and the preferred irradiation dose is around 10 to 1000 krad.

[0193] The lower limit of the gel fraction of the adhesive (adhesive irradiated with active energy rays) constituting the cured adhesive layer is preferably 35% or more, particularly preferably 50% or more, and even more preferably 65% ​​or more. If the lower limit of the gel fraction of the adhesive after irradiation with active energy rays is as described above, the durability becomes higher. Furthermore, the upper limit of the gel fraction is preferably 90% or less, particularly preferably 80% or less, and even more preferably 75% or less. If the upper limit of the gel fraction of the adhesive after irradiation with active energy rays is as described above, it is possible to prevent a decrease in the adhesive strength and a deterioration in the durability of the cured adhesive layer. The method for determining the gel fraction of the adhesive after irradiation with active energy rays is shown in the test examples described below.

[0194] The lower limit of the adhesion force of the adhesive sheet having the cured adhesive layer to soda-lime glass is preferably 10 N / 25 mm or more, more preferably 20 N / 25 mm or more, particularly preferably 30 N / 25 mm or more, and even more preferably 40 N / 25 mm or more. If the lower limit of the adhesion force is as described above, the durability of the obtained product (touch panel 2) is improved. In addition, the upper limit of the adhesion force is not particularly limited, but it is generally preferred to be 100 N / 25 mm or less, particularly preferably 80 N / 25 mm or less, and even more preferably 60 N / 25 mm or less.

[0195] The aforementioned adhesion refers to the adhesion measured essentially by the 180-degree peel method according to JIS Z0237:2009. The method involves preparing a test sample 25 mm wide and 100 mm long, attaching the test sample to the object to be adhered to, applying pressure of 0.5 MPa and 50°C for 20 minutes, irradiating it with active energy rays (ultraviolet light) under the conditions shown in the test examples described below, placing it under normal pressure, 23°C, and 50% RH for 24 hours, and then measuring the value at a peeling speed of 300 mm / min.

[0196] Even when the touch panel 2 is placed under high temperature and high humidity conditions and a voltage is applied to the electrode 52 under these conditions, the migration of the electrode 52 can be effectively suppressed. In addition, the change in the resistance value of the electrode 52 can also be effectively suppressed. Thus, malfunction of the touch panel 2 caused by a broken wire or short circuit of the electrode 52 can be prevented.

[0197] Here, the change in resistance of electrode 52 will be specifically explained. For the laminate obtained by bonding soda-lime glass and an electrode plate (silver wire electrode plate in the embodiment) via the adhesive layer 11 of the adhesive sheet 1 of this embodiment, during the durability test, the rate of change in resistance of the electrode plate calculated by the following formula is preferably less than 50%, particularly preferably less than 30%, and even more preferably less than 15%. Furthermore, the lower limit is not particularly limited, but is preferably 0% or more. Similarly, for the laminate obtained by bonding soda-lime glass and an ITO vapor-deposited film via the adhesive layer 11 of the adhesive sheet 1 of the embodiment, during the durability test, the rate of change in resistance of the ITO vapor-deposited film calculated by the following formula is preferably less than 200%, particularly preferably less than 150%, and even more preferably less than 100%. Furthermore, the lower limit is not particularly limited, but is preferably 0% or more.

[0198] Resistance change rate (%) = {(RR)} 0 ) / R 0}×100

[0199] In the formula, R 0 R is the initial resistance value (Ω) before the durability test, and R is the resistance value (Ω) after the durability test.

[0200] The details of the method for measuring the rate of change of resistance are shown in the experimental examples described below.

[0201] The embodiments described above are provided for ease of understanding of the present invention and are not intended to limit the invention. Therefore, the elements disclosed in the above embodiments also cover all design changes or equivalents that fall within the technical scope of the present invention.

[0202] For example, either of the release tabs 12a and 12b in the adhesive sheet 1 can be omitted. Furthermore, in the touch panel 2, a printed layer 7 may not be formed on the covering material 6.

[0203] Example

[0204] The present invention will be further described in detail below through examples, etc., but the scope of the present invention is not limited by these examples, etc.

[0205] [Example 1]

[0206] 1. Preparation of (meth)acrylate polymer (A)

[0207] (Meth)acrylate polymer (A) was prepared by copolymerization of 60 parts by mass of 2-ethylhexyl acrylate, 20 parts by mass of methyl methacrylate, and 20 parts by mass of 2-hydroxyethyl acrylate using solution polymerization. The molecular weight of (meth)acrylate polymer (A) was determined using the method described below, and the weight-average molecular weight (Mw) was 700,000.

[0208] 2. Preparation of adhesive compositions

[0209] 100 parts by mass (conversion value of solid content; the same below) of the (meth)acrylate polymer (A) obtained in step 1 above, 0.15 parts by mass of 1H-benzotriazole (B1) as a rust inhibitor (B), 0.15 parts by mass of polyoxyethylene alkylamine (weight average molecular weight: 900, number of carbon atoms of R: 14-18, sum of the values ​​of m and n: 15) as a long-chain alkylamine (C), 0.25 parts by mass of organosilicon compound (D1) as a silane compound (D) as a silane compound (II), 1.0 parts by mass of dipropylene glycol monomethyl ether as an alkylene glycol (E), and 0.6 parts by mass of trimethylolpropane-modified toluene diisocyanate (manufactured by TOYOCHEM CO.,LTD, product name "BHS8515") as a crosslinking agent (F) are mixed and stirred thoroughly, and diluted with methyl ethyl ketone to obtain a coating solution of adhesive composition.

[0210] [Chemical Formula 3]

[0211]

[0212] [Chemical Formula 4]

[0213]

[0214] Table 1 shows the proportions (converted to solids) of the adhesive composition when (meth)acrylate polymer (A) is set at 100 parts by weight. The abbreviations, ingredients, and other details listed in Table 1 are as follows.

[0215] [(Meth)acrylate polymer (A)]

[0216] 2EHA: 2-Ethylhexyl acrylate

[0217] MMA: Methyl methacrylate

[0218] HEA: 2-Hydroxyethyl acrylate

[0219] IBXA: Isoborneol Acrylate

[0220] ACMO: N-Acryloylmorpholine

[0221] BA: n-Butyl acrylate

[0222] [Rust Inhibitor (B)]

[0223] B1: 1H-benzotriazole

[0224] B2: 1-[N,N-bis(2-ethylhexyl)aminomethyl]methylbenzotriazole

[0225] [Silane compound (D)]

[0226] D1: Organosilicon compounds represented by the above structural formula (II)

[0227] D2: Organosilicon compounds represented by the following structural formula (III)

[0228] [Chemical Formula 5]

[0229]

[0230] [Active Energy Ray Curing Component (G)]

[0231] ε-Caprolactone-modified tris(2-acryloyloxyethyl)isocyanurate

[0232] [Photopolymerization initiator (H)]

[0233] A 1:1 (mass ratio) mixture of 1-hydroxy-cyclohexyl-phenyl-one and benzophenone

[0234] [UV absorber]

[0235] 2,2-Dihydroxy-4-methoxybenzophenone

[0236] 3. Manufacturing of adhesive sheets

[0237] Using a doctor blade coater, the coating solution of the adhesive composition obtained in step 2 above is applied to the release-treated surface of a heavy-release release sheet (manufactured by Lintec Corporation, product name "SP-PET382150", thickness: 38 μm) on which one side of a polyethylene terephthalate film has been released using a silicone release agent. Then, it is heated at 80°C for 1 minute and further heated at 110°C for 1 minute to form a coating layer (thickness: 50 μm).

[0238] Next, the coating layer on the obtained heavy-release release sheet is bonded to a light-release release sheet (manufactured by Lintec Corporation, product name "SP-PET381130") that has been peeled from one side of the polyethylene terephthalate film using a silicone release agent, with the peeled side of the light-release release sheet in contact with the coating layer. The bond is then cured for 7 days at 23°C and 50% RH to produce an adhesive sheet consisting of a heavy-release release sheet / adhesive layer (thickness: 50 μm) / light-release release sheet.

[0239] [Examples 2-11, Comparative Examples 1-7]

[0240] Except for changing the types and proportions of the monomers constituting the (meth)acrylate polymer (A), the weight-average molecular weight of the (meth)acrylate polymer (A), the type and amount of the rust inhibitor (B), the amount of the long-chain alkylamine (C), the type and amount of the silane compound (D), the amount of the alkylene glycol (E), and the amount of the crosslinking agent (F) as shown in Table 1, the adhesive sheet was manufactured in the same manner as in Example 1. Furthermore, an ultraviolet absorber was further added in Example 2, and active energy radiation curable component (G) and photopolymerization initiator (H) were further added in Examples 6, 7, 9, 10 and Comparative Examples 6 and 7.

[0241] Here, the weight-average molecular weight (Mw) mentioned above is the weight-average molecular weight converted from polystyrene determined using gel permeation chromatography (GPC) under the following conditions (GPC determination).

[0242] <Measurement Conditions>

[0243] • GPC measuring apparatus: Manufactured by TOSOH CORPORATION, HLC-8020

[0244] • GPC column (passes through in the following order): Manufactured by TOSOH CORPORATION

[0245] TSK guard column HXL-H

[0246] TSK gel GMHXL (×2)

[0247] TSK gel G2000HXL

[0248] • Solvent for determination: Tetrahydrofuran

[0249] • Measurement temperature: 40℃

[0250] [Experimental Example 1] (Determination of Gel Fraction)

[0251] The adhesive sheet obtained in the examples and comparative examples was cut into 80mm × 80mm sizes. The adhesive layer was wrapped in a polyester mesh (mesh size 200), and its mass was weighed using a precision balance. The mass of the mesh alone was subtracted to calculate the mass of the adhesive itself. This mass is denoted as M1.

[0252] Next, at room temperature (23°C), the adhesive encased in the aforementioned polyester mesh was immersed in ethyl acetate for 24 hours. The adhesive was then removed and air-dried at 23°C and 50% relative humidity for 24 hours, followed by further drying in an oven at 80°C for 12 hours. After drying, its mass was measured using a precision balance, and the mass of the mesh alone was subtracted to calculate the mass of the adhesive itself. This mass is denoted as M2. The gel fraction (%) is expressed as (M2 / M1) × 100. The results are shown in Table 2.

[0253] In addition, for the adhesive sheets of Examples 6, 7, 9, 10 and Comparative Examples 6, 7, the gel fraction was measured before and after irradiation of the adhesive layer with ultraviolet (UV) light (from the side of the heavy-peel type release sheet). The UV irradiation conditions are as follows.

[0254] <Ultraviolet Irradiation Conditions>

[0255] • Use a high-pressure mercury lamp

[0256] Illuminance 200mW / cm 2 Light intensity 1000 mJ / cm 2

[0257] The UV illuminance photometer used is the "UVPF-A1" manufactured by EYE GRAPHICS Co., Ltd.

[0258] [Experimental Example 2] (Determination of Haze Value)

[0259] The adhesive layer of the adhesive sheet prepared in the examples and comparative examples was adhered to the glass and used as the sample for measurement. Based on the background measurement of the glass, the haze value (total light haze value; %) of the above-mentioned sample was measured using a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd., product name "NDH-5000") in accordance with JIS K7136:2000. The results are shown in Table 2.

[0260] [Experimental Example 3] (Determination of Total Transmittance)

[0261] The adhesive layer of the adhesive sheet prepared in the examples and comparative examples was adhered to the glass and used as the sample for measurement. Based on the background measurement of the glass, the total transmittance (%) of the above-mentioned sample was measured using a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd., product name "SH-7000") in accordance with JIS K7361-1:1997. The results are shown in Table 2.

[0262] [Experimental Example 4] (Determination of L*a*b* color system)

[0263] For the adhesive layer of the adhesive sheets prepared in the examples and comparative examples, the chromaticity a* and chromaticity b* as specified by the CIE 1976 L*a*b* color system were measured using a simultaneous photometric spectrophotometer (manufactured by Nippon Denshoku Industries Co., Ltd., product name "SQ2000"). The results are shown in Table 2.

[0264] [Experimental Example 5] (Determination of Adhesion)

[0265] A light-release release sheet was peeled off from the adhesive sheet obtained in the examples and comparative examples. The exposed adhesive layer was then bonded to the easy-adhesive layer of a polyethylene terephthalate (PET) film (manufactured by TOYOBO CO.,LTD., product name "PETA4300", thickness: 100 μm) with an easy-adhesive layer, resulting in a laminate of release sheet / adhesive layer / PET film. The resulting laminate was cut into pieces 25 mm wide and 100 mm long and used as samples.

[0266] Under conditions of 23°C and 50% RH, the heavy-release peeling sheet was peeled off from the above samples. The exposed adhesive layer was then attached to soda-lime glass (manufactured by Nippon Sheet Glass Co., Ltd.). A pressure of 0.5 MPa and 50°C was applied for 20 minutes using a pressure heater manufactured by KURIHARA Corporation. After being left at 23°C and 50% RH for 24 hours, the adhesion (N / 25 mm) was measured using a tensile testing machine (ORIENTEC Co., Ltd., TENSILON) at a peeling speed of 300 mm / min and a peeling angle of 180 degrees. Conditions not described here were measured according to JIS Z0237:2009. The results are shown in Table 2.

[0267] In addition, the adhesive strength of the adhesive sheets of Examples 6, 7, 9, 10 and Comparative Examples 6, 7 were also measured after ultraviolet (UV) irradiation. Specifically, after the above-described heat treatment, the adhesive layer was irradiated with ultraviolet light from the soda-lime glass side under the same conditions as in Test Example 1. Then, after being placed at 23°C and 50% RH for 24 hours, the adhesive strength (N / 25mm; after UV) was measured in the same manner as described above. The results are shown in Table 2.

[0268] [Experimental Example 6] (Evaluation of the effect of preventing migration)

[0269] (1) Fabrication of silver wire electrode plate

[0270] Silver paste (manufactured by Toray Industries, Inc., product name "lumirrorU48", thickness: 125μm) was applied to the easily bonded surface of a polyethylene terephthalate (PET) film (manufactured on one side by an easy-bond treatment, product name "RA FS088"), with the positive and negative electrode wirings arranged in straight, parallel lines. The paste was then cured by heat treatment at 135°C for 30 minutes, resulting in an electrode plate with silver wiring (silver wiring electrode plate). The width of the positive and negative electrode wirings was 30μm, and the distance between the wirings was 30μm.

[0271] (2) Evaluation of the effect of preventing migration

[0272] A light-release release sheet was peeled off from the adhesive sheet obtained in the examples and comparative examples. The exposed adhesive layer was then bonded to the easy-adhesive layer of a polyethylene terephthalate (PET) film (manufactured by TOYOBO CO.,LTD., product name "PETA4300", thickness: 100 μm) with an easy-adhesive layer, resulting in a laminate of a heavy-release release sheet / adhesive layer / PET film. Next, the heavy-release release sheet was peeled off from the laminate, and the exposed adhesive layer was attached to the wiring of the positive and negative electrodes. Then, after a pressure heat treatment at 50°C and 0.5 MPa for 20 minutes, the laminate was placed at 23°C and 50% RH for 24 hours, and this was used as a sample.

[0273] In addition, for the adhesive sheets of Examples 6, 7, 9, 10 and Comparative Examples 6 and 7, after the above-mentioned heat treatment, the adhesive layer was irradiated with ultraviolet light from the PET film side under the same conditions as in Test Example 1, and they were used as samples.

[0274] The samples were placed under humid heat conditions of 105°C and 100% RH, and a migration test was conducted by applying a 5V voltage between the electrodes under these conditions. Twenty hours after the start of the test, the wiring of the positive and negative electrodes was observed using an optical microscope (magnification: 10x), and the mitigation effect was evaluated according to the evaluation criteria shown below. The results are shown in Table 2. Furthermore, no defects such as bubbling, peeling, or bubbling were observed in any of the examples or comparative examples.

[0275] ◎: No dissolution of the wiring in the positive electrode or dendrite formation in the wiring in the negative electrode was observed.

[0276] 〇: Although no dissolution of the wiring in the positive electrode or dendrite formation in the wiring in the negative electrode was observed, discoloration of the wiring was observed.

[0277] ×: Dissolution of the wiring in the positive electrode or dendrite formation in the wiring in the negative electrode were observed.

[0278] [Experimental Example 7] (Evaluation of Resistance Change)

[0279] The sample prepared in Experiment 6 was used as the measurement sample A (silver wire electrode plate sample).

[0280] Furthermore, using the adhesive layer of the adhesive sheet obtained in the examples and comparative examples, soda-lime glass (70mm x 150mm x 1.0mm; manufactured by Nippon Sheet Glass Co., Ltd.) and an ITO vapor-deposited film (manufactured by OIKE&Co., Ltd., product name "TETOLIGHT TCF KH150NMH2-125-U6 / T2", with the ITO vapor-deposited film side in contact with the adhesive layer) were bonded together. Then, after undergoing a pressure heat treatment at 50°C and 0.5MPa for 20 minutes, the sample was placed at 23°C and 50%RH for 24 hours to obtain test sample B (ITO vapor-deposited film sample).

[0281] In addition, for the adhesive sheets of Examples 6, 7, 9, 10 and Comparative Examples 6 and 7, after the above-mentioned heat treatment, the adhesive layer was irradiated with ultraviolet light from the soda-lime glass side under the same conditions as in Test Example 1, and these were used as test samples.

[0282] For the above-mentioned sample A, the initial resistance value R was measured by applying a 5V voltage between the positive and negative wiring. 0 (Ω). On the other hand, for the above-mentioned sample B, the initial resistance value R was measured using a non-contact resistivity meter (manufactured by NAPSON, product name "EC-80"). 0 (Ω).

[0283] Next, samples A and B were placed in a humid environment at 105°C and 100% RH for 3 hours. Then, they were left to stand at room temperature and humidity at 23°C and 50% RH for 24 hours, and their resistance values ​​(Ω) were measured in the same manner as the initial resistance values. This value was taken as the resistance value R after the durability test. Based on the measured value, the rate of change of resistance value (%) was calculated using the following formula.

[0284] Resistance change rate (%) = {(RR)} 0 ) / R 0}×100

[0285] Then, based on the calculated rate of change of resistance value, the change in resistance value is evaluated according to the following criteria. The results are shown in Table 2.

[0286] <Evaluation Criteria for Silver Wiring Electrode Plate Samples>

[0287] ◎: Resistance change rate is less than 15%

[0288] ○: The rate of change in resistance is greater than 15% but less than 30%.

[0289] △: The rate of change of resistance is greater than 30% but less than 50%.

[0290] ×: Resistance value change rate is above 50%

[0291] <Evaluation Criteria for ITO Evaporated Film Samples>

[0292] ◎: Resistance change rate is less than 100%

[0293] ○: The rate of change of resistance is greater than 100% but less than 150%.

[0294] △: The rate of change of resistance is greater than 150% but less than 200%.

[0295] ×: Resistance value change rate is over 200%

[0296]

[0297]

[0298] As shown in Table 2, the adhesive sheet obtained according to the embodiments can prevent migration in the silver wiring electrode plate. Furthermore, the adhesive sheet obtained according to the embodiments can suppress changes in the resistance of the silver wiring electrode plate and the ITO vapor-deposited film.

[0299] Industrial applicability

[0300] The adhesive composition, adhesive, and adhesive sheet of the present invention can be suitably used, for example, in electrostatic capacitive touch panels. Furthermore, the display body of the present invention is suitable, for example, as an electrostatic capacitive touch panel.

Claims

1. An adhesive composition, characterized in that, It contains a (meth)acrylate polymer (A), a rust inhibitor (B), a long-chain alkylamine (C), and a silane compound (D) having alkoxysilyl groups at both ends, wherein the silane compound (D) is a compound represented by the following general formula (I). R in general formula (I) 1 The R group is optionally a divalent hydrocarbon group having a nitrogen atom; 1 The number of carbon atoms in the divalent hydrocarbon group is 1 to 10; R in general formula (I) 2 ~R 7 Each is independently an alkyl group; the R 2 ~R 7 The alkyl groups have 1 to 6 carbon atoms. The rust inhibitor (B) is an azole. The (meth)acrylate polymer (A) contains 6% by mass and 35% by mass of hydroxyl-containing monomers as monomeric units constituting the polymer. Relative to 100 parts by weight of the (meth)acrylate polymer (A), the content of the rust inhibitor (B) in the adhesive composition is 0.01 parts by weight or more and 2 parts by weight or less, the content of the long-chain alkylamine (C) is 0.01 parts by weight or more and 2 parts by weight or less, and the content of the silane compound (D) is 0.01 parts by weight or more and 2 parts by weight or less. The long-chain alkyl group in the long-chain alkylamine has 10 or more but less than 24 carbon atoms.

2. The adhesive composition according to claim 1, characterized in that, It contains alkylene glycols (E).

3. The adhesive composition according to claim 1, characterized in that, The long-chain alkylamine (C) is a tertiary amine.

4. The adhesive composition according to claim 1, characterized in that, It contains a cross-linking agent (F).

5. The adhesive composition according to claim 1, characterized in that, The (meth)acrylate polymer (A) does not contain carboxyl-containing monomers as monomer units constituting the polymer.

6. The adhesive composition according to claim 1, characterized in that, It contains ultraviolet absorbers.

7. The adhesive composition according to claim 1, characterized in that, It is an adhesive composition for forming an adhesive in contact with an electrode made of metal or metal oxide.

8. An adhesive formed by crosslinking the adhesive composition according to any one of claims 1 to 7.

9. An adhesive sheet, characterized in that, It possesses: Two peeling plates; and The adhesive layer is held between the release tabs in a manner that contacts the release surfaces of the two release tabs. The adhesive layer is composed of the adhesive as described in claim 8.

10. A display body comprising: a first display body component, a second display body component, and an adhesive layer for bonding the first display body component and the second display body component together, characterized in that, The first display body component and / or the second display body component have electrodes made of metal or metal oxide on at least one side of the surface to be bonded. The adhesive layer is composed of the adhesive as described in claim 8.

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