TWI691570B - Adhesive composition, adhesive sheet and display - Google Patents

Abstract

The present invention provides an adhesive composition, adhesive sheet, and display that can effectively prevent and suppress migration. The adhesive composition forms an adhesive for bonding a first display component member and a second display component member having a step difference at least on the side of the bonding, wherein the first display component member and/ Or the second display component member has an electrode at least on the side of the bonding side, the adhesive composition contains (meth)acrylate polymer (A), a silane coupling agent (B) having a mercapto group, and active energy ray hardening Sexual component (C).

Description

Adhesive composition, adhesive sheet and display

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

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

Recently, large-scale touch panels have been sought, and as such electrode materials for touch panels, research is being conducted on mesh-shaped metal electrodes, such as copper electrodes or silver electrodes. However, if a conventional adhesive is used in contact with a metal electrode, especially a copper electrode or a silver electrode, ion migration (=electrochemical migration; hereinafter, simply referred to as "migration") may occur. Specifically, in the positive electrode, the electrode dissolves to cause wire breakage, or in the negative electrode, the precipitation of the positive electrode component forms dendrite crystals to cause a short circuit.

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

However, Patent Document 1 has disclosed compounds containing benzotriazole As an anti-rust agent, it is an adhesive composition for touch panels.

【Prior Technical Literature】 【Patent Literature】

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

However, even if the benzotriazole compound as a rust inhibitor has an anticorrosive effect for metal wiring, it cannot sufficiently prevent and suppress migration.

The present invention has been completed in view of the above-mentioned actual circumstances, and its object is to provide an adhesive composition, an adhesive sheet, and a display that can effectively prevent and suppress migration.

In order to achieve the above object, first, the present invention provides an adhesive composition formed to bond a first display body constituent member and a second display body constituent member having a step difference at least on the side of the bonding side An adhesive, wherein the adhesive composition is characterized in that the first display component member and/or the second display component member has an electrode at least on the surface on the side to be bonded, and the adhesive composition contains (methyl) An acrylate polymer (A), a silane coupling agent having a mercapto group (B), and an active energy ray-curable component (C) (Invention 1).

The adhesive obtained from the adhesive composition of the above invention (Invention 1), especially by the action of a silane coupling agent (B) having a mercapto group, can effectively prevent and suppress the adhesive from contacting the first display body Migration among the electrodes constituting the member and/or the second display member.

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

In the above inventions (Inventions 1 and 2), the organosilicon compound constituting the thiol-containing silane coupling agent (B) preferably has a mercapto group equivalent of 100 g/mole or more and 1000 g/mole or less (Invention 3).

In the above invention (Inventions 1 to 3), the content of the mercapto group-containing silane coupling agent (B) in the adhesive composition is 0.01 mass with respect to 100 mass parts of the (meth)acrylate polymer (A). More than 5 parts by mass is preferable (Invention 4).

In the above invention (Inventions 1 to 4), the content of the active energy ray-curable component (C) in the adhesive composition is 0.5 mass with respect to 100 mass parts of the (meth)acrylate polymer (A) More than 50 parts by mass is preferable (Invention 5).

In the above invention (Inventions 1 to 5), the (meth)acrylate polymer (A) preferably contains a hydroxyl group-containing monomer of 3% by mass or more and 35% by mass or less as a monomer unit constituting the polymer (Invention 6).

In the above inventions (Inventions 1 to 6), it is preferable that the adhesive composition further contains a crosslinking agent (D) (Invention 7).

Second, the present invention provides an adhesive sheet characterized by having a pre-hardened adhesive layer (Invention 8) formed by thermally cross-linking the aforementioned adhesive composition (Inventions 1 to 7).

In the above invention (Invention 8), the adhesive sheet includes two release sheets, and the adhesive layer is preferably held between the release sheets so as to be in contact with the release surfaces of the two release sheets (Invention 9).

Third, the present invention provides a display body, which includes: at least The surface of the bonded side has a first display component member having a step difference; a second display component member; and an adhesive layer for bonding the first display component member and the second display component member to each other, the display The feature of the body is that the first display body constituent member and/or the second display body constituent member have electrodes at least on the surface on the side where they are bonded, and the adhesive layer is formed by irradiating the active energy ray to the adhesive sheet ( Invention 8 and 9) obtained by hardening the adhesive layer before curing (Invention 10).

The adhesive composition, adhesive sheet and display according to the present invention can effectively prevent and suppress migration.

1‧‧‧ Adhesive sheet

10‧‧‧adhesive layer before hardening

12a, 12b ‧‧‧ peeling sheet

2‧‧‧Touch panel

3‧‧‧Display module

4, 11‧‧‧ adhesive layer

5a‧‧‧The first thin film sensor

5b‧‧‧The second thin film sensor

51‧‧‧ Base film

52‧‧‧Printed layer

6‧‧‧Cover material

7‧‧‧Printed layer

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

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

FIG. 3 is a reference image of an evaluation criterion in the evaluation of the migration prevention effect of Test Example 3.

Hereinafter, embodiments of the present invention will be described.

[Adhesive composition]

The adhesive composition of the present embodiment (hereinafter, sometimes referred to as "adhesive composition P") is formed on the first display body constituent member and the second display body that have a step difference at least on the surface on the side to be bonded The adhesive composition of the adhesive to which the constituent members are bonded, the first display body constituent member and/or the second display body constituent member have electrodes on at least the surface on the side where they are bonded. In addition, the adhesive composition P contains (a Group) acrylate polymer (A), a silane coupling agent having a mercapto group (B), and an active energy ray-curable component (C), and further containing a crosslinking agent (D) is preferred.

The "adhesive" in the present invention refers to a person that is cured by irradiation of active energy rays before curing the adhesive obtained by thermally crosslinking the adhesive composition. Similarly, the "adhesive layer" refers to a layer that is hardened by irradiation of active energy rays before the hardened adhesive layer formed by thermally crosslinking the adhesive composition. In this specification, (meth)acrylate refers to both acrylate and methacrylate. Other similar terms are also the same. In addition, the concept of "copolymer" is also included in "polymer". In addition, the display and the display component will be described later.

Since the adhesive composition P of this embodiment contains a silane coupling agent (B) having a mercapto group, when the adhesive obtained from the adhesive composition P comes into contact with the electrode, the positive electrode can prevent and suppress the dissolution of the electrode, and the negative electrode Can prevent and inhibit the formation of dendrite crystals. That is, it is possible to effectively prevent and suppress migration in the electrode (this effect is sometimes referred to as "migration prevention effect"). With this, even when the above-mentioned adhesive comes into contact with, for example, an electrode that is made finer and narrower in pitch, it is possible to prevent wire breakage and short circuit of the electrode. In particular, when the electrode is an electrode of a touch panel, it is possible to prevent defective driving of the touch panel due to disconnection and short circuit of the electrode.

Among them, as the above-mentioned electrode, for example, a metal electrode composed of copper, silver, etc. (including a mesh, a grid), a transparent conductive film composed of tin-doped indium oxide (ITO), etc. (including a patterned one) Wait. Among the above electrodes, a metal electrode mainly composed of an unoxidized metal, specifically, a metal electrode composed of copper or silver is preferred. Compared with metal oxides such as ITO, unoxidized metals Although the ionization tendency is high, the adhesive obtained from the adhesive composition P of this embodiment can effectively prevent disconnection and short circuit of the electrode even in this case.

In addition, the adhesive layer obtained from the adhesive composition P containing the silane coupling agent (B) having a mercapto group exists at the interface with the display member constituting the adherend from the silane coupling agent (B) having a mercapto group The components thereby have high adhesion to the display constituent member and excellent step followability. Specifically, even before the hardened adhesive layer formed by thermally cross-linking the adhesive composition P is attached to the display member having a step difference, the hardened adhesive layer is hardened by irradiation of active energy rays After being used as an adhesive layer, when exposed to high-temperature and high-humidity conditions (for example, at 85°C and 85%RH for 72 hours), it can also suppress the generation of bubbles, floating, peeling, etc. near the step (high-temperature and high-humidity conditions) (The following step is excellent in followability). With this, it is possible to suppress the reflection loss of light in the vicinity of the step difference, and it is possible to maintain the image quality of the display body satisfactorily.

In addition, the adhesive layer formed by hardening the adhesive layer before hardening by irradiation of active energy rays has high cohesion and exhibits a relatively high elastic modulus, so it has excellent anti-foaming properties. In addition, there is a component derived from the silane coupling agent (B) having a mercapto group at the interface between the adhesive layer and the adherend, and the adhesion to the display constituent member is high, so it is more excellent in the above anti-foaming property . For example, even if the display body bonded to the display body structure member by the above-mentioned adhesive layer is placed under high temperature and high humidity conditions (for example, at 85°C, 85%RH for 72 hours) and is composed of a display body composed of a plastic plate or the like In the case of outgassing from the member, it is also possible to suppress the occurrence of blistering phenomena such as bubbles, floating, and peeling on the interface between the adhesive layer and the display member.

(1) (Meth)acrylate polymer (A)

(Meth) acrylate polymer (A) By containing an alkyl (meth) acrylate alkyl ester having 1 to 20 carbon atoms as a monomer unit constituting the polymer, it can exhibit better adhesion . From this viewpoint, the (meth)acrylate polymer (A) contains an alkyl (meth)acrylate having a lower limit of 50% by mass or more and an alkyl group having 1 to 20 carbon atoms as the constituent polymer The monomer unit of the substance is preferable, and it is more preferably 60% by mass or more, and further preferably 70% by mass or more. If the above (meth)acrylic acid alkyl ester is contained in an amount of 50% by mass or more, the (meth)acrylate polymer (A) can exhibit better adhesion. Further, the (meth)acrylate polymer (A) preferably contains the above-mentioned alkyl (meth)acrylate having an upper limit of 97% by mass or less as a monomer unit constituting the polymer, and contains 90% by mass The following is particularly preferable, and the content of 85% by mass or less is even more preferable. By containing 97 mass% or less of the above-mentioned (meth)acrylic acid alkyl ester, a preferable amount of other monomer components can be introduced into the (meth)acrylate polymer (A).

Examples of the alkyl (meth)acrylate having 1 to 20 carbon atoms in the alkyl group include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, and (meth) Group) n-butyl acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, (meth)acrylic acid N-decyl ester, n-dodecyl (meth)acrylate, myristyl (meth)acrylate, cetyl (meth)acrylate, octadecyl (meth)acrylate, ( Cyclohexyl meth)acrylate, isobornyl (meth)acrylate, adamantyl (meth)acrylate, etc. Among them, from the viewpoint of further improving the adhesiveness, it contains an alkyl group (Meth)acrylate having 4 to 8 carbon atoms is preferred. These can be used alone or in combination of two or more. In addition, the alkyl group in the alkyl (meth)acrylate having 1 to 20 carbon atoms means a linear, branched or cyclic alkyl group.

In addition, as a (meth)acrylic acid alkyl ester having an alkyl group having 1 to 20 carbon atoms, a combination of a homopolymer having a glass transition temperature (Tg) exceeding 0°C (70°C or more is preferred) is used in combination Also, a soft monomer having a glass transition temperature (Tg) of 0°C or less as a homopolymer is also preferred. This is because the soft monomer maintains the adhesiveness and flexibility, and the hard monomer improves the cohesive force, whereby it can be set to be more excellent in step followability and anti-foaming resistance in a display panel (touch panel).

The mass ratio of the hard monomer to the soft monomer is preferably 5:95~40:60, especially 20:80~30:70.

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

Among the above-mentioned hard monomers, methyl acrylate, methyl methacrylate, and isobornyl acrylate are preferable from the viewpoint of preventing influence on other properties such as adhesion and transparency and further exerting the performance of the hard monomer. If adhesiveness is also considered, methyl acrylate and methyl methacrylate are more preferred, and methyl methacrylate is particularly preferred.

As the above soft monomer, preferably, it has a carbon number of 2 ~12 straight chain or branched chain alkyl acrylate alkyl ester. For example, 2-ethylhexyl acrylate (Tg-70°C), n-butyl acrylate (Tg-54°C), etc. are preferably mentioned. These can be used alone or in combination of two or more.

The (meth)acrylate polymer (A) preferably contains a monomer containing a reactive functional group as a monomer unit constituting the polymer. The reactive functional group derived from the reactive functional group-containing monomer reacts with a cross-linking agent (D) described later, thereby forming a cross-linked structure (three-dimensional network structure), and can obtain a desired cohesion before hardening Adhesive.

As the reactive functional group-containing monomer contained in the (meth)acrylate polymer (A) as a monomer unit constituting the polymer, preferably, a monomer having a hydroxyl group in the molecule (hydroxyl group-containing monomer) Monomer), a monomer having a carboxyl group in the molecule (carboxyl group-containing monomer), a monomer having an amine group in the molecule (amine group-containing monomer), etc. Among these, a hydroxyl group-containing monomer excellent in reactivity with the cross-linking agent (D) and resistance to moist heat and whitening, and having little effect on the electrode's hull is particularly preferred.

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

Examples of the carboxyl group-containing monomer include acrylic acid and methylpropyl Ethylene acid, crotonic acid, maleic acid, itaconic acid, citraconic acid and other ethylenically unsaturated carboxylic acids. Among them, acrylic acid is preferred from the viewpoint of the reactivity of the carboxyl group and the crosslinking agent (D) in the obtained (meth)acrylate polymer (A) and the copolymerizability with other monomers. These can be used alone or in combination of two or more.

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

The (meth)acrylate polymer (A) preferably contains a hydroxyl group-containing monomer with a lower limit of 3% by mass or more as a monomer unit constituting the polymer, and preferably contains 10% by mass or more, and contains 15% by mass % Or more is further preferable. Further, the (meth)acrylate polymer (A) preferably contains a hydroxyl group-containing monomer with an upper limit value of 35% by mass or less as a monomer unit constituting the polymer, and particularly preferably contains 30% by mass or less. 25 mass% or less is more preferable. If the (meth)acrylate polymer (A) contains a hydroxyl group-containing monomer as the monomer unit in the above amount, a certain amount of hydroxyl groups will remain in the obtained adhesive. Hydroxyl group hydrophilic group, if the hydrophilic group has a certain amount in the adhesive, even if the adhesive is placed under high temperature and high humidity conditions, and the water immersed in the adhesive under the high temperature and high humidity conditions The compatibility is also good, and as a result, it is possible to suppress the whitening of the adhesive when returning to normal temperature and humidity (excellent moisture-heat whitening resistance).

As the degree of whitening inhibition, the haze value of the adhesive layer (value measured in accordance with JIS K7136: 2000) after returning to normal temperature and humidity after applying high temperature and high humidity conditions is preferably 1.0% or less, more preferably 0.9% or less, 0.8% The following are further preferred. In addition, the adhesive layer also has a haze value as described above under normal conditions Is better. If the haze value is 1.0% or less, the transparency is very high, making it suitable for optical applications.

However, if the hydrophilic group exists in the adhesive in a predetermined amount as described above, the adhesive easily absorbs water, and the electrode in contact with the adhesive is likely to migrate. However, the adhesive composition P of this embodiment contains a silane coupling agent (B) having a mercapto group, which can effectively prevent and suppress migration in the contacted electrode.

The (meth)acrylate polymer (A) preferably does not contain a carboxyl group-containing monomer as the monomer unit constituting the polymer, but it is allowed to contain a certain amount. This is because the carboxyl acid component is generally concerned about migration of the target member, but the adhesive obtained from the adhesive composition P containing the silane coupling agent (B) having a mercapto group can exert a migration prevention effect even if there is a carboxyl group . Specifically, the (meth)acrylate polymer (A) is allowed to contain a carboxyl group-containing monomer as a monomer unit in an amount of 5% by mass or less, preferably 2% by mass or less.

The (meth)acrylate polymer (A) may contain other monomers as a monomer unit constituting the polymer, if necessary. As other monomers, in order not to hinder the function of the reactive functional group-containing monomer, a monomer containing no reactive functional group is preferred. Examples of such other monomers include methoxyalkyl (meth)acrylates such as methoxyethyl (meth)acrylate and ethoxyethyl (meth)acrylate, and (meth)acrylic acid. Non-crosslinkable tertiary amine groups such as N,N-dimethylaminoethyl, (meth)acrylic acid N,N-dimethylaminopropyl, (meth)acryloylmorpholine, etc. (Meth)acrylate, (meth)acrylamide, dimethylacrylamide, vinyl acetate, styrene, etc. These can be used alone or in combination of two or more.

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

The lower limit of the weight average molecular weight of the (meth)acrylate polymer (A) is preferably 200,000 or more, more preferably 300,000 or more, and further preferably 400,000 or more. If the lower limit value of the weight average molecular weight of the (meth)acrylate polymer (A) is the above or more, the obtained adhesive will become more excellent in step followability under high temperature and high humidity conditions. In addition, the weight average molecular weight in this specification is the value of standard polystyrene measured by the gel permeation chromatography (GPC) method.

Furthermore, the upper limit of the weight average molecular weight of the (meth)acrylate polymer (A) is preferably 1 million or less, more preferably 900,000 or less, and further preferably 700,000 or less. If the upper limit of the weight average molecular weight of the (meth)acrylate polymer (A) is equal to or less than the above, the obtained adhesive layer before curing becomes more excellent in step followability when attaching.

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

(2) Silane coupling agent with mercapto group (B)

The silane coupling agent (B) having a mercapto group is composed of an organic silicon compound having at least one mercapto group and at least one alkoxysilyl group in the molecule. Considering the use of the obtained adhesive, the silane coupling agent (B) having a mercapto group is preferably light-transmissive, for example, substantially transparent.

Specific examples of the silane coupling agent (B) having a mercapto group include 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyldimethoxymethylsilane Mercapto-containing low-molecular-weight silane coupling agent; 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyldimethoxymethylsilane and other mercapto group-containing silane compounds Mercapto-containing oligomer type silanes such as co-condensates with alkyl-containing silane compounds such as methyltriethoxysilane, ethyltriethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, etc. Coupling agent, etc. Among them, a thiol group-containing oligomer-type silane coupling agent with better migration prevention effect and good workability is preferred, and a co-condensate of a mercapto group-containing silane compound and an alkyl group-containing silane compound is particularly preferred, 3-mercaptopropane The co-condensate of trimethoxysilane and methyltriethoxysilane is further preferred. These can be used alone or in combination of two or more.

The lower limit value of the mercapto group equivalent of the organosilicon compound constituting the silane coupling agent (B) having a mercapto group is preferably 100 g/mole or more, more preferably 120 g/mole or more, and even more preferably 150 g/mole or more. By setting the lower limit value as described above, the polarity difference from the (meth)acrylate polymer (A) is set within an appropriate range, so that the silane coupling agent (B) can be set in the adhesive composition P The better the dispersion.

The upper limit value of the mercapto group equivalent of the organosilicon compound constituting the silane coupling agent (B) having a mercapto group is preferably 1,000 g/mole or less, more preferably 800 g/mole or less, and further preferably 500 g/mole or less. By setting the upper limit value as described above, it is possible to prevent deterioration of optical characteristics caused by phase separation from the (meth)acrylate polymer (A).

The content of the mercapto group-containing silane coupling agent (B) in the adhesive composition P is preferably 0.01 mass parts or more relative to 100 mass parts of the (meth)acrylate polymer (A), and 0.05 mass parts is preferable More preferably, it is more than 0.1 part by mass, and more preferably 0.1 part by mass or more. Also, the upper limit is 5 parts by mass or less Preferably, 1.5 parts by mass or less is particularly preferable, and 1.0 parts by mass or less is even more preferable. When the content of the silane coupling agent (B) having a mercapto group is in the above-mentioned range, it becomes a more excellent migration prevention effect.

In addition, the lower limit of the number of moles (mercapto group) of the mercapto group in the silane coupling agent (B) per 100 g of the (meth)acrylate polymer (A) is preferably 0.01 mmol or more, particularly 0.1 mmol or more Preferably, 0.2 mmol or more is more preferable. In addition, the upper limit of the molar number is preferably 30 mmol or less, more preferably 5 mmol or less, and further preferably 1.5 mmol or less. When the molar number of the mercapto group of the silane coupling agent (B) relative to the (meth)acrylate polymer (A) is within the above range, it can be considered that the migration prevention effect is more excellent.

(3) Active energy ray hardening component (C)

If the adhesive composition P contains the active energy ray-curable component (C), the active energy ray hardenability when the pre-curing adhesive prepared by thermally cross-linking the adhesive composition P is irradiated with active energy rays The components (C) are mutually polymerized, and it is estimated that the polymerized active energy ray-curable component (C) is entangled in the cross-linked structure (three-dimensional network structure) of the (meth)acrylate polymer (A). The adhesive with such a high-order structure has high cohesion and a relatively high elastic modulus, so it has excellent anti-foaming properties.

The active energy ray-curable component (C) is not particularly limited as long as it is hardened by active energy ray irradiation to obtain the above-mentioned effects, and may be any of monomers, oligomers, or polymers. It can be a mixture of these. Among them, preferably, a polyfunctional acrylate monomer having a molecular weight of less than 1,000 and having excellent compatibility with (meth)acrylate polymer (A) or the like is mentioned.

Examples of the multifunctional acrylate monomer having a molecular weight of less than 1000 include 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, and neopentyl diacrylate. Alcohol di(meth)acrylate, polyethylene glycol di(meth)acrylate, neopentyl glycol adipate di(meth)acrylate, hydroxypivalate neopentyl glycol di(meth) Acrylate, dicyclopentyl di(meth)acrylate, caprolactone modified dicyclopentyl di(meth)acrylate, ethylene oxide modified di(meth)acrylate, di(propylene) Acetyloxyethyl) isocyanurate, allylated cyclohexyl di(meth)acrylate, ethoxylated bisphenol A diacrylate, 9,9-bis[4-(2-propenyl) Oxyethoxy)phenyl] stilbene and other 2-functional types; trimethylolpropane tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, propionic acid modified dipentaerythritol tri(meth)acrylic acid Ester, pentaerythritol tri (meth) acrylate, propylene oxide modified trimethylol propane tri (meth) acrylate, tri (acryloyloxyethyl) isocyanurate, ε-caprolactone modified 3-functional types such as tri-(2-(meth)acryloyloxyethyl) isocyanurate; 4-functional types such as diglycerol tetra(meth)acrylate and pentaerythritol tetra(meth)acrylate; Propionic acid modified dipentaerythritol penta(meth)acrylate and other 5 functional types; dipentaerythritol hexa(meth)acrylate, caprolactone modified dipentaerythritol hexa(meth)acrylate and other 6 functional types. Among the above, from the viewpoint of the anti-foaming property of the obtained adhesive, pentaerythritol tri(meth)acrylate and ε-caprolactone modified tri-(2-(meth)acryloyloxyethyl Radical) isocyanurate is preferred. These can be used alone or in combination of two or more.

As the active energy ray-curable component (C), an active energy ray-curable acrylate oligomer can also be used. It is preferable that the acrylate-based oligomer has a weight average molecular weight of 50,000 or less. As this kind of acrylic Examples of ester oligomers include polyester acrylates, epoxy acrylates, urethane acrylates, polyether acrylates, polybutadiene acrylates, and silicone acrylates. Department etc.

The weight average molecular weight of the acrylate oligomer is preferably 50,000 or less, more preferably 500 to 50,000, and even more preferably 3,000 to 40,000. One type of these acrylate oligomers may be used alone, or two or more types may be used in combination.

In addition, as the active energy ray-curable component (C), an addition acrylate polymer in which a group having a (meth)acryloyl group is introduced into the side chain can also be used. This kind of addition acrylate polymer can be obtained by using a copolymer of (meth)acrylate and a monomer having a crosslinkable functional group in the molecule, and making a part of the crosslinkable functional group of the copolymer, It is obtained by reacting with a compound having a group capable of reacting with a (meth)acryloyl group and a crosslinkable functional group.

The weight average molecular weight of the above-mentioned addition acrylate-based polymer is preferably about 50,000 to 900,000, and particularly preferably about 100,000 to 500,000.

The active energy ray-curable component (C) may be one kind selected from the aforementioned multifunctional acrylate monomers, acrylate oligomers, and addition acrylate polymers, or two or more kinds may be used in combination, or Used in combination with other active energy ray hardening components.

The content of the active energy ray-curable component (C) in the adhesive composition P is polymerized relative to the (meth)acrylate from the viewpoint of improving the cohesive force of the obtained adhesive and making it excellent in anti-foaming property. 100 parts by mass of the substance (A), the lower limit is preferably 0.5 parts by mass or more, more preferably 1.0 parts by mass or more Preferably, 3.0 parts by mass or more is particularly preferable. On the other hand, from the viewpoint of preventing phase separation of the active energy ray curable component (C) and the (meth)acrylate polymer (A), the upper limit of the content is preferably 50 parts by mass or less, 20 A mass part or less is more preferable, and further considering the viewpoint of making the anti-foaming property more favorable, it is particularly preferably 12 mass parts or less.

(4) Crosslinking agent (D)

It is preferable that the adhesive composition P contains a crosslinking agent (D). The adhesive composition P contains a cross-linking agent (D) to cross-link the (meth)acrylate polymer (A) to form a three-dimensional network structure, which can further increase the cohesive force of the obtained adhesive, thereby further improving The step followability under high temperature and high humidity conditions.

The crosslinking agent (D) may be any one that reacts with the reactive group of the (meth)acrylate polymer (A), and examples thereof include isocyanate-based crosslinking agents and epoxy-based crosslinking agents. , Amine-based crosslinking agent, melamine-based crosslinking agent, aziridine-based crosslinking agent, amine-based crosslinking agent, aldehyde-based crosslinking agent, oxazoline-based crosslinking agent, metal alkoxide-based crosslinking agent, Metal chelate-based cross-linking agent, metal salt-based cross-linking agent, ammonium salt-based cross-linking agent, etc. When the (meth)acrylate polymer (A) contains a hydroxyl group-containing monomer as a monomer unit constituting the polymer, it is preferable to use an isocyanate-based crosslinking agent excellent in reactivity with the hydroxyl group. In addition, the crosslinking agent (D) may be used alone or in combination of two or more.

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

The content of the cross-linking agent (D) in the adhesive composition P is preferably 0.001 parts by mass or more, and more preferably 0.01 parts by mass or more with respect to 100 parts by mass of the (meth)acrylate polymer (A). Preferably, 0.02 parts by mass or more is more preferable. In addition, the upper limit value is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and further preferably 1 part by mass or less.

When the content of the cross-linking agent (D) is in the above range, the resulting adhesive has better cohesion, and the step followability of the adhesive under high temperature and high humidity conditions is further improved.

(5) Photopolymerization initiator (E)

When ultraviolet rays are used as active energy rays irradiated to the adhesive before hardening when the adhesive before hardening is hardened, it is preferable that the adhesive composition P further contains a photopolymerization initiator (E). In this way, by containing the photopolymerization initiator (E), the active energy ray-curable component (C) can be efficiently polymerized, and the polymerization hardening time and the irradiation amount of the active energy ray can be reduced.

Examples of the photopolymerization initiator (E) include benzoin, benzoin methyl ether, benzoin ether, benzoin isopropyl ether, benzoin n-butyl ether, benzoin isobutyl ether, acetophenone, and dimethylaminobenzene Acetone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenyl Propan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1-[4-(methylthio) Phenyl]-2-morpholino-propan-1-one, 4-(2-hydroxyethoxy)phenyl-2-(hydroxy-2-propyl) ketone, benzophenone, p-phenyl di Benzophenone, 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-dimethylamino benzoate, oligo[2-hydroxy-2-methyl-1[4-(1-methylethylene Group) phenyl] acetone], 2,4,6-trimethylbenzyl-diphenyl-phosphine oxide, etc. These can be used alone or in combination of two or more.

The content of the photopolymerization initiator (E) in the adhesive composition P is preferably 100 parts by mass or less relative to the active energy ray-curable component (C), and the lower limit is preferably 0.1 part by mass or more, particularly 1 part by mass or more good. In addition, the upper limit value is preferably 30 parts by mass or less, and more preferably 10 parts by mass or less.

(6) Various additives

To the adhesive composition P, various additives commonly used in acrylic adhesives, such as antistatic agents, tackifiers, antioxidants, ultraviolet absorbers, light stabilizers, softeners, fillers, and refractive indexes may be added as needed. Modifiers, silane coupling agents other than mercapto group-containing silane coupling agents (B), etc. However, the rust inhibitor, especially the benzotriazole-based rust inhibitor, has an effect of inhibiting the crosslinking of the adhesive composition P, and therefore it is not preferred.

In addition, the adhesive composition P represents a mixture of various components remaining in the original state or the state of reaction in the adhesive layer, and the components removed during the drying process, such as the polymerization solvent and the dilution solvent described later, are not included in the adhesive Sexual composition P.

(7) Manufacture of adhesive composition

The adhesive composition P can be produced by manufacturing a (meth)acrylate polymer (A) and obtaining the (meth)acrylate polymer (A), a silane coupling agent having a mercapto group (B), and active energy rays The hardenable component (C) is mixed, and a crosslinking agent (D), a photopolymerization initiator (E) and additives are added as needed to manufacture.

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

Examples of the polymerization initiator include azo compounds and organic peroxides, and two or more types may be used in combination. Examples of the azo-based compound include 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), and 1,1'-azobis(cyclohexyl) Alkane 1-carbonitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethyl-4-methoxypentane Nitrile), dimethyl 2,2'-azobis (2-methyl propionate), 4,4'-azobis (4-cyanovaleric acid), 2,2'-azobis ( 2-hydroxymethylpropionitrile), 2,2'-azobis[2-(2-imidazolin-2-yl)propane], etc.

Examples of organic peroxides include benzoyl peroxide, tert-butyl peroxybenzoate, cumene hydroperoxide, diisopropyl peroxide, di-n-propyl peroxide, and di-n-propyl peroxide. (2-ethoxyethyl) peroxydicarbonate, tert-butyl peroxyneodecanoate, tert-butyl peroxypivalate, (3,5,5-trimethylhexyl) peroxide, Dipropylamide peroxide, diethylamide peroxide, etc.

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

When the (meth)acrylate polymer (A) is obtained, the silane coupling agent (B) having a mercapto group and the active energy ray-curable component (C) are added to the solution of the (meth)acrylate polymer (A) And, if necessary, the crosslinking agent (D), the photopolymerization initiator (E), the additive, and the dilution solvent are thoroughly mixed, thereby obtaining the adhesive composition P (coating solution) diluted by the solvent.

As the dilution solvent, for example, aliphatic hydrocarbons such as hexane, heptane, cyclohexane, aromatic hydrocarbons such as toluene and xylene, halogenated hydrocarbons such as dichloromethane and dichloroethane, methanol, ethanol, propanol, Alcohols such as butanol, 1-methoxy-2-propanol, acetone, methyl ethyl ketone, 2-pentanone, isophorone, cyclohexanone and other ketones, ethyl acetate, butyl acetate and other esters, ethyl cellosolve Cellosolve and other solvents.

The concentration and viscosity of the coating solution prepared in this way are not particularly limited as long as they can be coated, and can be appropriately selected according to the situation. For example, the concentration diluted to the adhesive composition P becomes 10 to 40% by mass. In addition, when a coating solution is obtained, addition of a dilution solvent or the like is not a necessary condition, and as long as the adhesive composition P has a coatable viscosity or the like, the dilution solvent may not be added. At this time, the adhesive composition P becomes a coating solution using the polymerization solvent of the (meth)acrylate polymer (A) directly as the dilution solvent.

〔Adhesive sheet〕

As shown in FIG. 1, the adhesive sheet 1 of the present embodiment is composed of two peeling sheets 12a, 12b; and the two peeling sheets 12a, 12b in contact with the peeling surfaces of the two peeling sheets 12a, 12b The hardened adhesive layer 10 sandwiched between 12a and 12b. However, in the adhesive sheet 1, the peeling sheets 12a and 12b are not necessarily required to constitute The pieces are peeled and removed when the adhesive sheet 1 is used. In addition, the peeling surface of the peeling sheet in this specification means the surface which has peelability in a peeling sheet, and includes both the surface which performed peeling processing, and the surface which shows peeling property even if peeling processing was not performed.

(1) Adhesive layer before hardening

The adhesive layer 10 before hardening is formed by thermally cross-linking the adhesive composition P to form a layer, and is the one before hardening by irradiation with active energy rays. The lower limit of the thickness of the adhesive layer 10 (value measured in accordance with JIS K7130) before curing is preferably 10 μm or more, more preferably 25 μm or more, and still more preferably 50 μm or more. When the lower limit value of the thickness of the adhesive layer 10 before hardening is the above, the adhesive layer obtained by hardening the adhesive layer 10 before hardening can fully exhibit excellent adhesive force. In addition, the upper limit of the thickness of the adhesive layer 10 before curing is preferably 300 μm or less, more preferably 250 μm or less, and even more preferably 100 μm or less. When the upper limit of the thickness of the adhesive layer 10 before hardening is the above or less, the workability becomes good. In addition, the adhesive layer 10 before hardening may be formed as a single layer, or may be formed by laminating a plurality of layers.

(2) Peel off piece

The release sheets 12a and 12b are not particularly limited, 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 can be used , Polyethylene naphthalate film, polybutylene terephthalate film, polyurethane film, ethylene vinyl acetate film, ionomer resin film, ethylene. (Meth)acrylic copolymer film, ethylene. (Meth)acrylate copolymer film, polystyrene film, polycarbonate Ester film, polyimide film, fluororesin film, etc. In addition, such a crosslinked film can also be used. In addition, such a laminated film may be used.

It is preferable that the peeling surfaces of the above-mentioned peeling sheets 12a and 12b (especially the surface in contact with the adhesive layer 10 before hardening) be peeled. Examples of the release agent used in the release treatment include alkyd-based, silicone-based, fluorine-based, unsaturated polyester-based, polyolefin-based, and wax-based release agents. In the peeling sheets 12a and 12b, it is preferable that one peeling sheet is a heavy peeling type peeling sheet having a large peeling force and the other peeling sheet is a light peeling type peeling sheet having a small peeling force.

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

(3) Manufacture of adhesive sheet

As a manufacturing example of the adhesive sheet 1, the coating liquid of the above-mentioned adhesive composition P is applied to the peeling surface of one release sheet 12a (or 12b), and heat treatment is performed to thermally crosslink the adhesive composition P to form After coating the layer, the peeling surface of another peeling sheet 12b (or 12a) is overlaid on the coating layer. When the curing period is required, the coating layer becomes the adhesive layer 10 before curing by passing through the curing period, and when the curing period is not needed, the coating layer directly becomes the adhesive layer 10 before curing. Thereby, the above-mentioned adhesive sheet 1 is obtained. In addition, the drying treatment at the time of volatilization of the dilute solvent of the applied adhesive composition P or the like may also be used as the heating treatment.

When performing heat treatment, the heating temperature is preferably 50 to 150°C, and particularly preferably 70 to 120°C. Moreover, the heating time is preferably 30 seconds to 10 minutes, and more preferably 50 seconds to 2 minutes. When the aging period is set, the condition is preferably about 1 to 2 weeks at normal temperature (for example, 23° C., 50% RH).

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

As another manufacturing example of the adhesive sheet 1, the coating liquid of the above-mentioned adhesive composition P is applied to the peeling surface of one release sheet 12a, and heat treatment is performed to crosslink the adhesive composition P to form a coating layer. To obtain a release sheet 12a with a coating layer. Then, the coating liquid of the adhesive composition P is applied to the peeling surface of the other release sheet 12b, and heat treatment is performed to crosslink the adhesive composition P to form a coating layer, thereby obtaining a tape coating layer之 peeling sheet 12b. And the peeling sheet 12a with a coating layer and the peeling sheet 12b with a coating layer are bonded so that two coating layers may contact each other. When the curing period is required, the above-mentioned laminated coating layer becomes the pre-curing adhesive layer 10 through the curing period, and when the curing period is not required, the above-mentioned laminated coating layer directly becomes the pre-curing adhesive layer 10. By comparison, the above-mentioned adhesive sheet 1 can be obtained. According to this manufacturing example, even when the adhesive layer 10 before curing is thick, it can be stably manufactured.

(4) Gel fraction

The lower limit of the gel fraction of the adhesive before hardening obtained by thermally crosslinking the adhesive composition P is preferably 20% or more, more preferably 30% or more, and even more preferably 40% or more. If the lower limit value of the gel fraction of the adhesive before hardening is above the above, the cohesive force of the adhesive hardened by active energy ray irradiation will become higher and it will become more excellent in anti-foaming property. In addition, the upper limit of the gel fraction is preferably 90% or less, more preferably 80% or less, and further preferably 75% or less. If the upper limit of the gel fraction of the adhesive before hardening is the above or less, the adhesive layer 10 before hardening will not become too hard, and it will be excellent in the step followability at the time of attachment.

On the other hand, the active agent The lower limit of the gel fraction of the adhesive hardened by irradiation of the wire is preferably 50% or more, more preferably 60% or more, and further preferably 70% or more. If the lower limit value of the gel fraction of the adhesive is above the above, the cohesive force of the adhesive becomes high, and it becomes more excellent in the anti-foaming property. In addition, the upper limit of the gel fraction is preferably 99% or less, more preferably 96% or less, and even more preferably 94% or less. If the upper limit of the gel fraction of the adhesive is equal to or less than the above, proper adhesion can be maintained and good foaming performance can be maintained. In addition, the method of measuring the adhesive fraction and the gel fraction of the adhesive before hardening is shown in the test example described later.

(5) Adhesion

The lower limit of the adhesive force of the adhesive sheet 1 of the present embodiment to soda lime glass is preferably 5 N/25 mm or more, more preferably 7 N/25 mm or more, and even more preferably 10 N/25 mm or more. If the lower limit value of the adhesive force of the adhesive sheet 1 is above the above, it is possible to effectively prevent peeling of the peeling sheet during storage, or peeling between the adherend and the like during the conveyance process. On the other hand, the upper limit of the above-mentioned adhesive force is not particularly limited. If considering the ease of peeling off the release sheets 12a and 12b from the adhesive layer 10 before curing, 50N/25mm or less is preferable, and 30N/ Below 25mm is particularly preferred. If further reworkability is considered, 26 N/25 mm or less is preferable. In this case, even if erroneous bonding occurs, the display component member can be easily reused.

The above-mentioned adhesive force basically means the adhesive force measured by the 180-degree peeling method according to JIS Z0237:2009. The measurement sample is set to 25 mm width and 100 mm length. After pressurizing at MPa and 50°C for 20 minutes, it was left under normal pressure, 23°C and 50% RH for 24 hours, and then measured at a peeling speed of 300 mm/min.

Furthermore, when the adhesive layer 10 before hardening of the adhesive sheet 1 of the present embodiment is hardened by irradiation of active energy rays to serve as an adhesive layer, the lower limit value of the adhesive force of the adhesive sheet to soda lime glass is 5N/ 25 mm or more is preferable, 7N/25 mm or more is particularly preferable, and 10N/25 mm or more is even more preferable. If the lower limit value of the adhesive force of the adhesive sheet 1 is above the above, it will become more excellent in blistering resistance. On the other hand, the upper limit of the above-mentioned adhesive force is not particularly limited, but it is usually 50 N/25 mm or less.

The above-mentioned adhesive force basically means the adhesive force measured by the 180-degree peeling method according to JIS Z0237:2009. The measurement sample is set to 25 mm width and 100 mm length, and the measurement sample is attached to the adherend and is within 0.5 After pressurizing at MPa and 50°C for 20 minutes, the adhesive layer before hardening is cured by irradiation of active energy rays to serve as an adhesive layer, and then, after being left under normal pressure, 23°C and 50% RH for 24 hours , Measured at a peeling speed of 300 mm/min.

〔Display Body〕

The display body of this embodiment includes: a first display body structural member having a step difference at least on the side of the bonding side; a second display body structural member; and attaching the first display body structural member and the second display body structural member to each other Combine the adhesive layer. The first display body constituent member and/or the second display body constituent member have electrodes on at least the surface on the side to be bonded (adhesive layer side). As a preferable configuration, the second display component member has an electrode at least on the surface on the side to be bonded.

The above-mentioned adhesive layer is one in which the adhesive layer before hardening is hardened by irradiation of active energy rays. Among them, the active energy rays refer to those having energetics in electromagnetic waves or charged particle beams, and specific examples include ultraviolet rays and electron beams. In the active energy ray, ultraviolet light is particularly easy to operate.

The irradiation of ultraviolet rays can be performed by a high-pressure mercury lamp, a fusion H lamp, a xenon lamp, and the like, and the irradiation amount of ultraviolet rays is preferably about 50 to 1000 mW/cm ² . Moreover, the light quantity is preferably 50 to 10000 mJ/cm ² , more preferably 80 to 5000 mJ/cm ² , and particularly preferably 200 to 2000 mJ/cm ² . On the other hand, the irradiation of the electron beam can be performed by an electron beam accelerator or the like, and the irradiation amount of the electron beam is preferably about 10 to 1000 krad.

The irradiation of the active energy ray to the adhesive layer before hardening is performed by bonding the first display body constituent member and the second display body constituent member to each other through the adhesive layer before hardening, and the first display body constituent member and the second 2 It is preferable to perform the transmission of active energy rays among the display component members.

When the active energy ray is irradiated to the adhesive layer before hardening, the active energy ray hardening component (C) polymerizes and hardens. The adhesive layer obtained by hardening the adhesive layer before hardening by irradiation of active energy rays becomes very excellent in anti-foaming property.

Examples of the display include a liquid crystal (LCD) display, a light emitting diode (LED) display, an organic electroluminescence (organic EL) display, and electronic paper. A touch panel may also be used. Furthermore, as a display, it may be a member that constitutes a part of these.

The first display body constituent member may be a glass plate, a plastic plate, or the like. In addition, a protective panel composed of a laminate or the like including these is preferable. The first display component member has a step on the surface of the adhesive layer side, specifically, it is preferable to have a step formed by a printed layer. The printed layer is generally formed in a frame shape.

The glass plate is not particularly limited, and examples thereof include chemically strengthened glass, alkali-free glass, quartz glass, soda lime glass, and barium-containing. strontium Glass, aluminosilicate glass, lead glass, borosilicate glass, barium borosilicate glass, etc. The thickness of the glass plate is not particularly limited, but it is usually 0.1 to 5 mm, preferably 0.2 to 2 mm.

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

In addition, various functional layers (electrode layer, silicon oxide layer, hard coat layer, anti-glare layer, etc.) may be provided on one or both surfaces of the glass plate or plastic plate, and optical members may also be laminated.

The material constituting the printed layer is not particularly limited, and known materials for printing can be used. The lower limit of the thickness of the printed layer, that is, the height of the step is preferably 3 μm or more, more preferably 5 μm or more, particularly preferably 7 μm or more, and most preferably 10 μm or more. If the lower limit value is above the above, it becomes difficult for the electrical wiring to be viewed from the viewer side, etc., and the concealability can be sufficiently ensured. In addition, the upper limit value is preferably 50 μm or less, more preferably 35 μm or less, particularly preferably 25 μm or less, and further preferably 20 μm or less. When the upper limit value is equal to or less than the above, it is possible to prevent the adhesive layer from following the step difference of the printed layer from deteriorating.

The second display body component is an optical member, display body module (for example, liquid crystal (LCD) module, light-emitting diode (LED) module, organic electroluminescence that should be attached to the first display body component (Organic EL) module, etc.), an optical member that is part of the display module, or a laminate including the display module, preferably has electrodes at least on the surface on the adhesive layer side.

Examples of the optical member include electrode films, transparent conductive films, film sensors, metal nanowire films, and wire grid polarizing films. Wait.

Examples of the above-mentioned electrodes include metal electrodes (including meshes and grids) made of copper and silver, and transparent conductive films (including patterners) made of tin-doped indium oxide (ITO). As described above, among the above electrodes, a metal electrode mainly composed of an unoxidized metal, specifically, a metal electrode composed of copper or silver is preferred.

As an example of the display body of this embodiment, the touch panel 2 of the capacitance type is shown in FIG. 2. The touch panel 2 is configured to include: a display module 3; a first thin-film sensor 5a laminated via an adhesive layer 4; a second thin-film sensor laminated via a first adhesive layer 11 5b; a cover material 6 laminated on the second adhesive layer 11 thereon. Since the printed layer 7 is formed on the surface of the cover material 6 on the side of the second adhesive layer 11, there is a step formed by the presence or absence of the printed layer 7. In this embodiment, the cover material 6 corresponds to the above-mentioned first display constituent member, and the second film sensor 5b corresponds to the above-mentioned second display constituent member.

The first adhesive layer 11 and the second adhesive layer 11 in this embodiment consider these migration prevention effects, and both of them are set such that the adhesive layer 10 before curing of the adhesive sheet 1 is irradiated with active energy rays And the hardener. However, the present invention is not limited to this, and the first adhesive layer 11 may be formed of other adhesives or adhesive sheets. Examples of the adhesive in this case include acrylic adhesives, rubber adhesives, silicone adhesives, urethane adhesives, polyester adhesives, and polyvinyl ether adhesives. , Acrylic adhesive is better.

The adhesive layer 4 can be made of the adhesive before hardening of the above-mentioned adhesive sheet 1 The layer 10 is formed, and may also be formed by other adhesives or adhesive sheets. In the latter case, examples of the adhesive constituting the adhesive layer 4 include acrylic adhesives, rubber adhesives, silicone adhesives, urethane adhesives, polyester adhesives, and polyadhesives. Among vinyl ether adhesives, acrylic adhesives are preferred.

The first thin film sensor 5a and the second thin film sensor 5b in this embodiment include a base film 51 and an electrode 52 formed on the base film 51, respectively. The base film 51 is not particularly limited, and for example, polyethylene terephthalate film, acrylic film, polycarbonate film, etc. can be used.

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

The electrode 52 of the first thin-film sensor 5a and the electrode 52 of the second thin-film sensor 5b generally constitute one circuit pattern in the X-axis direction and the other circuit pattern in the Y-axis direction.

The electrode 52 of the second thin-film sensor 5b in this embodiment is located above the second thin-film sensor 5b in the second figure. On the other hand, the electrode 52 of the first thin-film sensor 5a is located on the upper side of the first thin-film sensor 5a in FIG. 2, but it is not limited to this, and may be located below the first thin-film sensor 5a. .

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

As the adhesive sheet 1, the first adhesive sheet 1 and the second adhesive sheet 1 are prepared. One peeling sheet 12a is peeled off from the first adhesive sheet 1, and the exposed pre-curing adhesive layer 10 (first pre-curing adhesive layer 10) is brought into contact with the first thin-film sensor 5a such that the electrode 52 contacts 1 The film sensor 5a is attached. Then, one peeling sheet 12a is peeled from the second adhesive sheet 1, and the exposed pre-curing adhesive layer 10 (second pre-curing adhesive layer 10) is brought into contact with the electrode 52 of the second thin-film sensor 5b The second thin film sensor 5b is bonded.

Then, the other release sheet 12b of the first adhesive sheet is peeled off, and the second pre-cured adhesive layer 10 is laminated with the exposed first pre-cured adhesive layer 10 and the second thin film sensor 5b. The surface on the opposite side (the exposed surface of the base film 51 of the first film sensor 5a) contacts the two so that they are in contact. Thereby, a laminate in which the release sheet 12b, the second pre-cured adhesive layer 10, the second thin-film sensor 5b, the first pre-cured adhesive layer 10, and the first thin-film sensor 5a are sequentially stacked is obtained.

Next, the adhesive layer 4 provided on the release sheet is bonded to the surface of the layered product on the side of the first film sensor 5a (the exposed surface of the base film 51 of the first film sensor 5a). Next, the release sheet 12b is peeled from the laminate, and the exposed second pre-cured adhesive layer 10 is bonded to the cover material such that the printed layer 7 side of the cover material 6 is in contact with the second pre-cured adhesive layer 10 6. At this time, since the second adhesive layer 10 before hardening is excellent in step followability at the time of attachment, it is possible to suppress the occurrence of gaps and floating near the step formed by the printed layer 7. By the above bonding, the covering material 6, the second pre-curing adhesive layer 10, the second film sensor 5b, the first pre-curing adhesive layer 10, the first film sensor 5a, and the adhesive layer 4 can be obtained And peeling sheets are stacked in this order.

Next, the second pre-cured adhesive layer 10 and the first pre-cured adhesive layer 10 are irradiated from either side of the above-mentioned structure, preferably from the cover material 6 side. The energy ray hardens the second pre-curing adhesive layer 10 and the first pre-curing adhesive layer 10 to serve as the second adhesive layer 11 and the first adhesive layer 11, respectively.

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

Even when the above-mentioned touch panel 2 is placed under high temperature and high humidity conditions and a voltage is applied to the electrode 52 in this state, the adhesive layer 11 in contact with the electrode 52 contains a silane coupling agent (B) derived from a mercapto group. The components can effectively suppress the migration of the electrode 52. With this, it is possible to prevent the driving failure of the touch panel 2 caused by the disconnection and short circuit of the electrode 52.

In addition, the adhesive layer 11 is excellent in step followability even under high-temperature and high-humidity conditions. Therefore, even when the touch panel 2 is exposed to high-temperature and high-humidity conditions for a predetermined period of time, the formation of the printed layer 7 can be effectively suppressed. Bubbles, floating, peeling, etc. are generated near the step.

In addition, even if the touch panel 2 is placed under high-temperature and high-humidity conditions to generate outgassing from the cover material 6, the second film sensor 5b, or the first film sensor 5a, the adhesive layer 11 has excellent anti-foaming properties Therefore, it is also possible to suppress blisters such as bubbles, floating, and peeling on the interface between the adhesive layer 11 and the covering material 6, the second film sensor 5b, or the first film sensor 5a.

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

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

【Example】

Hereinafter, the present invention will be further specifically described by examples, but the scope of the present invention is not limited to those examples.

[Example 1]

1. Preparation of (meth)acrylate copolymer

60 parts by mass of 2-ethylhexyl acrylate, 20 parts by mass of methyl methacrylate and 20 parts by mass of 2-hydroxyethyl acrylate were copolymerized to prepare a (meth)acrylate polymer (A). As a result of measuring the molecular weight of the (meth)acrylate polymer (A) by the method described later, the weight average molecular weight (Mw) was 600,000.

2. Preparation of adhesive composition

100 parts by mass of (meth)acrylate polymer (A) obtained in the above process 1 (converted value of solid content; the same below), 3-mercaptopropyltrimethoxy, which is a silane coupling agent (B) having a mercapto group Co-condensate of trisilane and methyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "X-41-1810", oligomer type, mercapto equivalent: 450 g/mole) 0.20 Mass parts, ε-caprolactone modified tri-(2-acryloyloxyethyl)isocyanurate (manufactured by Shin-Nakamura Chemical Co., Ltd., as active energy ray hardening component (C), product Name "NK Ester A-9300-1CL") 2.5 parts by mass, trimethylolpropane modified toluene diisocyanate (made by Nippon Polyurethane Industry Co., Ltd. as a crosslinking agent (D), product name "Coronate L" ) 0.23 parts by mass, as a photopolymerization initiator (E), a mixture of benzophenone and 1-hydroxycyclohexyl phenyl ketone in a mass ratio of 1:1 (manufactured by BASF, product name "IRGACURE 500" ") 0.25 parts by mass are mixed and fully stirred, and It was diluted with methyl ethyl ketone to obtain a coating solution of an adhesive composition having a solid content concentration of 36% by mass.

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

[(Meth)acrylate polymer (A)]

2EHA: 2-ethylhexyl acrylate

MMA: methyl methacrylate

HEA: 2-hydroxyethyl acrylate

[Silane coupling agent with mercapto group (B)]

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

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

[Other silane coupling agent]

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

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

[Active energy ray hardening component (C)]

NK Ester A-9300-1CL: ε-caprolactone modified tri-(2-propenyl oxyethylene) Base) isocyanurate (manufactured by Shin-Nakamura Chemical Co., Ltd., product name "NK Ester A-9300-1CL")

NK Ester A-TMM-3L: pentaerythritol triacrylate (triester 55 mass%) (manufactured by Shin-Nakamura Chemical Co., Ltd., product name "NK Ester A-TMM-3L")

3. Manufacturing of adhesive sheet

Peeling treatment of a heavy peeling type peeling sheet (product name "SP-PET382150" manufactured by LINTEC Corporation, thickness: 38 μm) obtained by peeling the polyethylene terephthalate film on one side with a silicone peeling agent On the surface, after applying the coating solution of the adhesive composition obtained in the above process 2 with a doctor blade coater, heat treatment was performed at 90°C for 1 minute to form a coating layer (thickness: 25 μm). Similarly, the peeling surface of the light peeling type release sheet (product name "SP-PET382120" manufactured by LINTEC Corporation) obtained by peeling the polyethylene terephthalate film on one side with a silicone-based peeling agent. After coating the coating solution of the adhesive composition obtained in the above process 2 with a blade coater, heat treatment is performed at 90°C for 1 minute to form a coating layer (thickness: 25 μm).

Next, the heavy peeling type release sheet with the coating layer obtained in the above and the light peeling type release sheet with the coating layer obtained in the above are laminated in such a manner that the two coating layers are in contact with each other, and the It was cured for 7 days under the conditions of 23° C. and 50% RH, thereby preparing an adhesive sheet composed of a heavy peeling type peeling sheet/adhesive layer before curing (thickness: 50 μm)/a light peeling type peeling sheet.

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

Change the silane coupling agent (silane coupling agent with mercapto group) as shown in Table 1. (B) and other silane coupling agents) types and ratios, types and ratios of active energy ray hardening components (C), crosslinking agents (D), and photopolymerization initiator (E), except Other than this, the adhesive sheet was produced like Example 1. In addition, for Comparative Examples 7 to 10, N,N-bis(2-ethylhexyl)-(4 or 5)-methyl-1H-benzotriazole-1-methylamine (manufactured by BASF, trade name) "IRGMET 39") was added as a rust inhibitor in the adhesive composition in the ratio shown in Table 1. In addition, the adhesive compositions of Comparative Examples 1 to 10 are non-hardening active energy rays. Generally, those obtained by thermally crosslinking the adhesive composition become adhesives, but for convenience, they are sometimes composed of the adhesive The layer is also called "adhesive layer before hardening".

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

<Measurement conditions>

. GPC measuring device: made by TOSOH CORPORATION, HLC-8020

. GPC column (passed in the following order): manufactured by TOSOH CORPORATION

TSK guard column HXL-H

TSK gel GMHXL (×2)

TSK gel G2000HXL

. Determination solvent: tetrahydrofuran

. Measuring temperature: 40℃

[Test Example 1] (Measurement of gel fraction)

The adhesive sheets obtained in the examples and comparative examples were cut to a size of 80 mm × 80 mm, and the adhesive layer before being cured was wrapped in a polyester mesh (mesh size 200) In the process, take the mass of the precision balance scale and subtract the mass of the above net to calculate the mass of the adhesive itself before hardening. Let the mass at this time be M1.

Next, at room temperature (23°C), the pre-curing adhesive wrapped in the polyester net was immersed in ethyl acetate for 24 hours. After that, the adhesive before hardening was taken out, air-dried for 24 hours in an environment with a temperature of 23° C. and a relative humidity of 50%, and dried in an oven at 80° C. for 12 hours. After drying, take the mass with a precision balance scale and subtract the mass of the above net alone to calculate the mass of the adhesive itself before hardening. Let the mass at this time be M2. The gel ratio (%) is represented by (M2/M1)×100. The results are shown in Table 2.

In addition, the pre-cured adhesive layer of the adhesive sheet obtained in the example was subjected to an ultraviolet irradiation device (manufactured by EYE GRAPHICS Co., Ltd., product name "Eye Grandage ECS-401GX type" through a light peeling type peeling sheet. ) UV rays are irradiated under the following conditions to harden the adhesive layer before curing to serve as an adhesive layer. For this adhesive layer, the gel fraction (%) was measured in the same manner as the adhesive layer before hardening. The results are shown in Table 2.

[UV irradiation conditions]

. Light source: high pressure mercury lamp

. Light quantity: 1000mJ/cm ²

. Illumination: 200mW/cm ²

[Test Example 2] (Measurement of Adhesion)

Lightly peel off the release sheet from the adhesive sheets obtained in Examples and Comparative Examples, and attach the exposed pre-hardened adhesive layer to a polyethylene terephthalate (PET) film (TOYOBO) with an easy-adhesive layer Made by CO., LTD., product name "PET A4300", thickness: 100μm) easy-to-adhesive layer, to obtain a heavy peel type Laminate of release sheet/adhesive layer before curing/PET film. The obtained laminate was cut into a width of 25 mm and a length of 100 mm, and used as a sample.

In an environment of 23° C. and 50% RH, the heavy-peel release sheet was peeled from the above sample, and the exposed adhesive layer before hardening was attached to soda lime glass (manufactured by Nippon Sheet Glass Co., Ltd.), and then used The autoclave made by KURIHARA CORPORATION was pressurized at 0.5 MPa and 50°C for 20 minutes. Thereafter, after being left under the conditions of 23° C. and 50% RH for 24 hours, the adhesion was measured using a tensile tester (manufactured by ORIENTEC Co., LTD., TENSILON) at a peeling speed of 300 mm/min and a peeling angle of 180 degrees. Force (N/25mm). Conditions other than those described here were measured in accordance with JIS Z 0237:2009. The results are shown in Table 2.

Then, after the above sample (only for the example) was attached to soda lime glass as described above and pressurized at 0.5 MPa and 50° C. for 20 minutes using an autoclave made by KURIHARA CORPORATION, the same ultraviolet rays as in Test Example 1 were applied. Under irradiation conditions, the adhesive layer before hardening is irradiated with ultraviolet rays through a PET film to harden the adhesive layer before hardening as an adhesive layer. For the sample having this adhesive layer, the adhesive force (N/25 mm) was measured in the same manner as above. The results are shown in Table 2.

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

(1) Fabrication of wiring board

Copper on a copper-clad laminate (manufactured by NIKKAN INDUSTRIES Co., Ltd., product name "NIKAFLEX") formed by laminating copper foil (thickness: 18 μm) and polyethylene terephthalate film (thickness: 50 μm) On the surface of the foil, a resist pattern is printed and etched by screen printing. Thereafter, the unnecessary copper foil is removed by etching Instead, a comb-shaped electrode is formed. The line width of each electrode is 300 μm, and the gap between the electrodes is 50 μm.

(2) Evaluation of migration prevention effect

From the adhesive sheets obtained in the examples and comparative examples, the light peeling type release sheet was peeled off, and the exposed pre-hardened adhesive layer was attached to a polyethylene terephthalate (PET) film (TOYOBO) with an easy adhesion layer Made by CO., LTD., product name "PET A4300", thickness: 100 μm) easy-adhesive layer, to obtain a laminate of a heavy peelable release sheet/adhesive layer before curing/PET film. Next, the heavy peeling type peeling sheet was peeled from the laminate, and the exposed adhesive layer before curing was attached to the comb-shaped electrode.

Under the same ultraviolet irradiation conditions as in Test Example 1, the above-mentioned pre-curing adhesive layer (only for the example) was irradiated with ultraviolet rays through a PET film to harden the pre-curing adhesive layer to serve as an adhesive layer.

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

◎: No dissolution of the electrode (positive electrode) and formation of dendrites in the electrode (negative electrode) were observed at all.

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

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

In addition, the reference image of the above-mentioned evaluation criteria is shown in FIG. 3.

[Experiment Example 4] (Evaluation of step followability)

(a) Preparation of samples for evaluation

Ultraviolet hardening ink (Teikoku Printing Inks Mfg. Co., is printed on the surface of a glass plate (manufactured by NSG Precision Co., Ltd., product name "Corning Glass EAGLE XG", 90 mm long x 50 mm wide x 0.5 mm thick) The product name "POS-911 Ink" manufactured by Ltd.) makes the thickness of the coating be any of 5 μm, 10 μm, 15 μm, and 20 μm (outer shape: vertical 90 mm × horizontal 50 mm, width 5 mm). Next, irradiate ultraviolet rays (80W/cm ² , two metal halide lamps, lamp height is 15cm, belt speed is 10~15m/min) to harden the printed ultraviolet curable ink, so as to produce by printing A glass plate with a step (the height of the step: any of 5 μm, 10 μm, 15 μm, and 20 μm) with a step.

The light peeling type release sheet was peeled off from the adhesive sheets obtained in Examples and Comparative Examples, and the exposed pre-hardened adhesive layer was attached to a polyethylene terephthalate (PET) film having an easy adhesion layer ( Easy adhesion layer manufactured by TOYOBO Co., Ltd., PET A4300, thickness: 100 μm). Next, the heavy peeling type peeling sheet is peeled off, and the adhesive layer before hardening is peeled off. Then, using a laminating machine (manufactured by FUJIPLA Inc., product name "LPD3214"), the above-mentioned laminated volume was layered onto each glass plate with a step such that the adhesive layer before hardening covered the entire printing surface in a frame shape.

Under the same ultraviolet irradiation conditions as in Test Example 1, the above-mentioned pre-curing adhesive layer (only for the example) was irradiated with ultraviolet rays through a PET film to harden the pre-curing adhesive layer to serve as an adhesive layer.

(b) Evaluation of samples for evaluation

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

◎: No bubbles and floating at all.

○: Less than 10 bubbles were observed near the step.

×: There are bubbles and/or floating.

[Test Example 5] (Evaluation of anti-foaming property)

A polyethylene terephthalate (PET) film with a transparent conductive film made of tin-doped indium oxide (ITO) sandwiched on one side of the pre-hardened adhesive layer of the adhesive sheet obtained in Examples and Comparative Examples (Oike & Co., Ltd., ITO film, thickness: 125μm) transparent conductive film and polycarbonate plate (Mitsubishi Gas Chemical Company, Inc., product name "Iupilon. sheet MR58", thickness: 1mm) From time to time, a laminate is obtained.

Under the conditions of 50°C and 0.5 MPa, the obtained laminate was subjected to autoclave treatment for 30 minutes. Furthermore, the laminate of the examples was irradiated with ultraviolet rays through the PET film under the same ultraviolet irradiation conditions as in Test Example 1, and the adhesive layer before curing was cured as an adhesive layer.

After the sample obtained as described above was left at normal pressure, 23° C., and 50% RH for 15 hours, it was stored under high temperature and high humidity conditions at 85° C. and 85% RH for 72 hours. Thereafter, bubbles, floating or peeling at the interface of the adhesive layer and the adherend were visually confirmed, and the anti-foaming resistance was evaluated according to the following criteria. The results are shown in Table 2.

◎...... No bubbles, floating and peeling at all.

○......Only bubbles with a diameter of 0.2 mm or less are generated.

×......Bubble, floating or peeling that exceeds 0.2mm straight.

[Test Example 6] (Evaluation of Dampness and Whitening Resistance)

The pre-hardened adhesive layer of the adhesive sheet obtained in the example or the comparative example was sandwiched between two pieces of non-alkali glass with a thickness of 1.1 mm to obtain a laminate. Furthermore, the laminate of the examples was irradiated with ultraviolet rays through a glass under the same ultraviolet irradiation conditions as in Test Example 1, and the adhesive layer before curing was cured to serve as an adhesive layer.

Under the conditions of 85° C. and 85% RH, the sample obtained as described above was stored for 120 hours. After that, normal temperature and humidity at 23° C. and 50% RH were restored, the presence or absence of whitening was visually confirmed according to the following criteria, the humidity-heat whitening resistance was evaluated, and the haze value of the adhesive layer was measured. The haze value was measured within 30 minutes after returning the sample to normal temperature and humidity using a haze meter (manufactured by NIPPON DENSHOKU INDUSTRIES Co., Ltd., product name "NDH2000") in accordance with JIS K7136:2000. The results are shown in Table 2.

○: Even if normal temperature and humidity were restored, no whitening was confirmed. Alternatively, some of them may be whitened, but disappear within 30 minutes.

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

【Table 1】

It can be seen from Table 2 that any of the adhesive sheet obtained in the examples has the effects of migration prevention, step-following, blistering resistance, and heat-heat-whitening resistance. Outstanding.

[Industry availability]

The adhesive composition and the adhesive sheet of the present invention can be preferably used for a touch panel using an electrostatic capacitance method using copper electrodes or silver electrodes, for example. In addition, the display body of the present invention is preferably used as a capacitive touch panel using a copper electrode or a silver electrode, for example.

1‧‧‧ Adhesive sheet

10‧‧‧adhesive layer before hardening

12a, 12b ‧‧‧ peeling sheet

Claims (9)

An adhesive composition for forming an adhesive for bonding a first display body structural member and a second display body structural member having a step difference on at least the side of the bonding, the characteristics of the adhesive composition is : The first display body constituent member and/or the second display body constituent member have an electrode at least on the surface on the bonding side, and the adhesive composition contains: (meth)acrylate polymer (A); has a mercapto group Silane coupling agent (B); and active energy ray hardening component (C), wherein the (meth)acrylate polymer (A) contains 10 mass% or more and 35 mass% or less of hydroxyl-containing monomers as the constituent The monomer unit of the polymer. The adhesive composition as described in item 1 of the patent application scope, wherein the silane coupling agent (B) having a mercapto group is an oligomer type silane coupling agent containing a mercapto group. The adhesive composition as described in item 1 of the patent application scope, wherein the organosilicon compound constituting the thiol-containing silane coupling agent (B) has a mercapto group equivalent of 100 g/mole or more and 1000 g/mole or less. The adhesive composition as described in item 1 of the patent application scope, wherein the content of the thiol-containing silane coupling agent (B) in the adhesive composition relative to the (meth)acrylate polymer (A ) 100 parts by mass is 0.01 parts by mass or more and 5 parts by mass or less. The adhesive composition according to item 1 of the patent application scope, wherein the active energy ray-curable component (C) in the adhesive composition contains The amount is 0.5 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the (meth)acrylate polymer (A). The adhesive composition as described in item 1 of the patent application scope, wherein the adhesive composition further contains a crosslinking agent (D). An adhesive sheet characterized by having a pre-hardened adhesive layer formed by thermally cross-linking the adhesive composition described in any one of claims 1 to 6. The adhesive sheet according to item 7 of the patent application scope, wherein the adhesive sheet includes two release sheets, and the pre-hardened adhesive layer is sandwiched between the release sheets in contact with the release surfaces of the two release sheets . A display body comprising: a first display body structural member having a step difference at least on a surface on which it is bonded; a second display body structural member; and the first display body structural member and the second display body structural member The adhesive layer for bonding is characterized in that the first display component and/or the second display component has an electrode at least on the side of the bonding, and the adhesive layer is formed by active energy rays It is obtained by curing the adhesive layer before curing of the adhesive sheet described in item 7 of the patent application scope by irradiation.

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