JP6554344B2 - Adhesive sheet and display - Google Patents

Description

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

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

  Recently, the touch panel has been increased in size, and meshed metal electrodes such as a copper electrode and a silver electrode have been studied as electrode materials for the touch panel. However, when a conventional pressure-sensitive adhesive is used in contact with a metal electrode, particularly, a copper electrode or a silver electrode, ion migration (= electrochemical migration; hereinafter simply referred to as “migration”) may occur. Specifically, in the positive electrode, the electrode is melted and disconnected, or in the negative electrode, dendrite is formed due to deposition of the positive electrode component, resulting in a short circuit.

  This migration is particularly likely to occur when a voltage is applied to the electrode under high temperature and high humidity. When such migration occurs, the touch panel cannot be driven normally. Particularly, in recent years when miniaturization of electrodes and narrowing of the pitch are progressing, disconnection / short-circuiting of electrodes due to migration is likely to occur.

  By the way, the adhesive composition for touchscreens which contains a benzotriazole compound as a rust preventive agent by patent document 1 is disclosed.

JP 2014-177611 A

  However, even though the benzotriazole compound as a rust preventive has the effect of preventing corrosion of metal wiring, it has not been able to sufficiently prevent or suppress migration.

  The present invention has been made in view of the above-described actual situation, and an object of the present invention is to provide a pressure-sensitive adhesive composition, a pressure-sensitive adhesive sheet, and a display capable of effectively preventing and suppressing migration.

  In order to achieve the above object, firstly, the present invention is for bonding a first display member constituting member having a step on at least a surface to be bonded and a second display member constituting member An adhesive composition for forming an adhesive, wherein the first display member constituting member and / or the second display member constituting member has an electrode at least on a surface to be bonded, and the adhesive Adhesive composition characterized by containing a (meth) acrylic acid ester polymer (A), a mercapto group-containing silane coupling agent (B), and an active energy ray-curable component (C) Provided is a sex composition (Invention 1).

  According to the pressure-sensitive adhesive obtained from the pressure-sensitive adhesive composition according to the above-mentioned invention (invention 1), the first display member-constituting member with which the pressure-sensitive adhesive comes in contact by the action of the silane coupling agent (B) And / or migration of the electrodes of the second display member constituting member can be effectively prevented / suppressed.

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

  In the said invention (invention 1-3), content of the said silane coupling agent (B) which has the said mercapto group in the said adhesive composition is 100 mass parts of said (meth) acrylic acid ester polymers (A). On the other hand, it is preferable that it is 0.01 to 5 mass parts (invention 4).

  In the said invention (invention 1-4), content of the said active energy ray hardening component (C) in the said adhesive composition is 100 mass parts of said (meth) acrylic acid ester polymers (A). It is preferable that it is 0.5 mass part or more and 50 mass parts or less (invention 5).

  In the above inventions (Inventions 1-5), the (meth) acrylic acid ester polymer (A) contains 3% by mass or more and 35% by mass or less of a hydroxyl group-containing monomer as a monomer unit constituting the polymer. Is preferred (Invention 6).

  In the said invention (invention 1-6), it is preferable that the said adhesive composition contains a crosslinking agent (D) further (invention 7).

  2ndly this invention provides the adhesive sheet which has the adhesive layer before hardening formed by heat-crosslinking the said adhesive composition (invention 1-7) (invention 8).

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

  A third aspect of the present invention is a first display member constituting member having a step on at least a surface to be bonded, a second display member constituting member, the first display member constituting member and the second member. A display comprising an adhesive layer for bonding display components to each other, wherein at least the first display component and / or the second display component is to be bonded A display having an electrode on the surface, wherein the pressure-sensitive adhesive layer is formed by curing the pressure-sensitive adhesive layer before curing of the pressure-sensitive adhesive sheets (Inventions 8 and 9) by irradiation with active energy rays. (Invention 10)

  According to the pressure-sensitive adhesive composition, the pressure-sensitive adhesive sheet, and the display of the present invention, migration can be effectively prevented and suppressed.

It is sectional drawing of the adhesive sheet which concerns on one Embodiment of this invention. It is a sectional view showing an example of 1 composition of a touch panel. It is a reference image of the evaluation standard in evaluation of the migration prevention effect of example 3 of an examination.

Hereinafter, embodiments of the present invention will be described.
[Adhesive composition]
The adhesive composition according to the present embodiment (hereinafter sometimes referred to as "adhesive composition P") has a first display member constituting member having a step on at least a surface to be bonded, and a second display component. It is an adhesive composition which forms an adhesive for pasting together with a display body constituent member, and the first display body constituent member and / or the second display body constituent member is at least a surface on the side to be pasted. Have an electrode. And the adhesive composition P contains a (meth) acrylic acid ester polymer (A), a silane coupling agent (B) having a mercapto group, and an active energy ray-curable component (C), preferably Additionally contains a crosslinking agent (D).

  Here, the “pressure-sensitive adhesive” in the present invention refers to a product obtained by curing a pre-curing pressure-sensitive adhesive obtained by thermally crosslinking a pressure-sensitive adhesive composition by irradiation with active energy rays. Similarly, the “pressure-sensitive adhesive layer” refers to a layer obtained by curing a pre-curing pressure-sensitive adhesive layer formed by thermally crosslinking a pressure-sensitive adhesive composition by irradiation with active energy rays. Moreover, in this specification, (meth) acrylic acid ester means both acrylic acid ester and methacrylic acid ester. The same applies to other similar terms. Further, the term “polymer” includes the concept of “copolymer”. In addition, a display body and a display body structural member are mentioned later.

  When the pressure-sensitive adhesive obtained from the pressure-sensitive adhesive composition P comes in contact with the electrode, the pressure-sensitive adhesive composition P according to the present embodiment contains the silane coupling agent (B) having a mercapto group. Dissolution is prevented / suppressed, and formation of dendrite is prevented / suppressed in the negative electrode. That is, migration in the electrode is effectively prevented and suppressed (this effect may be referred to as “migration preventing effect”). Thus, even when the pressure-sensitive adhesive contacts, for example, a miniaturized / narrowed electrode, disconnection or short circuit of the electrode is prevented. In particular, when the electrode is an electrode of a touch panel, driving failure of the touch panel due to disconnection or short circuit of the electrode can be prevented.

  Here, as the electrode, for example, a metal electrode (including mesh-like and grid-like ones) made of copper, silver or the like, a transparent conductive film made of tin-doped indium oxide (ITO) or the like (including a patterned one) Etc. Among the above-mentioned electrodes, a metal electrode mainly composed of a non-oxidized metal, specifically, a metal electrode consisting of copper or silver is preferable. Although metal that is not oxidized has a higher ionization tendency than metal oxides such as ITO, according to the pressure-sensitive adhesive obtained from the adhesive composition P according to the present embodiment, even in such a case, disconnection or short circuit of the electrode occurs. Effectively prevented.

  Moreover, the adhesive layer obtained from the adhesive composition P containing the silane coupling agent (B) having a mercapto group has a silane coupling having a mercapto group at the interface with the display member constituting member. By the presence of the component derived from the agent (B), the adhesion to the display member constituting member is high, and the step following property is excellent. Specifically, a pre-curing pressure-sensitive adhesive layer formed by thermally cross-linking the pressure-sensitive adhesive composition P is applied to a display member constituting member having a step, and the pre-curing pressure-sensitive adhesive layer is cured by irradiation with active energy rays. After forming the pressure-sensitive adhesive layer, even when exposed to high-temperature and high-humidity conditions (for example, at 85 ° C. and 85% RH for 72 hours), generation of bubbles, floats, peeling, etc. near the step is suppressed. (Excellent step following capability under high temperature and high humidity conditions). Thereby, the occurrence of the reflection loss of light in the vicinity of the step can be suppressed, and the image quality of the display can be maintained well.

  Furthermore, the pressure-sensitive adhesive layer formed by curing the pressure-sensitive adhesive layer before curing by irradiation of active energy rays has high cohesion and relatively high elastic modulus, and thus is excellent in blister resistance. Moreover, the component derived from the silane coupling agent (B) which has a mercapto group exists in the interface with the to-be-adhered body of the said adhesive layer, and since the adhesiveness with a display body structural member is high, the said blister resistance Is even better. For example, a display body constituting member formed of a plastic plate or the like is placed under a high temperature and high humidity condition (for example, at 85 ° C. and 85% RH for 72 hours) by sticking the display body constituting member with the adhesive layer. Even when outgas is generated from the above, occurrence of blisters such as bubbles, floats, and peeling at the interface between the pressure-sensitive adhesive layer and the display member constituting member is suppressed.

(1) (Meth) acrylic acid ester polymer (A)
The (meth) acrylic acid ester polymer (A) has a preferable adhesiveness by containing a (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms of an alkyl group as a monomer unit constituting the polymer. It can be expressed. From this point of view, the (meth) acrylic acid ester polymer (A) has, as a monomer unit constituting the polymer, a (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms of an alkyl group as the lower limit. It is preferable to contain by mass% or more, in particular to contain 60 mass% or more, and further preferable to contain 70 mass% or more. When the (meth) acrylic acid alkyl ester is contained in an amount of 50% by mass or more, the (meth) acrylic acid ester polymer (A) can exhibit suitable tackiness. Further, the (meth) acrylic acid ester polymer (A) preferably contains the above (meth) acrylic acid alkyl ester as an upper limit value of 97 mass% or less as a monomer unit constituting the polymer, particularly 90 mass%. It is preferable to contain% or less, and also it is preferable to contain 85 mass% or less. By containing 97% by mass or less of the (meth) acrylic acid alkyl ester, a suitable amount of other monomer components can be introduced into the (meth) acrylic acid ester polymer (A).

  Examples of the (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate and n- (meth) acrylate Butyl, n-pentyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, n-decyl (meth) acrylate, (meth) acrylate n-dodecyl, myristyl (meth) acrylate, palmityl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, adamantyl (meth) acrylate, etc. Among these, from the viewpoint of further improving the adhesiveness, the alkyl group having 4 to 8 carbon atoms is a (meth) a. It is preferred to include acrylic acid esters. These may be used alone or in combination of two or more. The alkyl group in the (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group means a linear, branched or cyclic alkyl group.

  Further, as a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 20 carbon atoms, a hard monomer having a glass transition temperature (Tg) exceeding 0 ° C. (preferably 70 ° C. or more) as a homopolymer, and a homopolymer It is also preferable to use in combination with a soft monomer having a glass transition temperature (Tg) of 0 ° C. or less. By improving cohesive force with a hard monomer while securing tackiness and flexibility with a soft monomer, it is possible to make the step followability and blister resistance in a display panel (touch panel) more excellent. .

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

  Examples of the hard monomer include methyl acrylate (Tg 10 ° C.), methyl methacrylate (Tg 105 ° C.), isobornyl acrylate (Tg 94 ° C.), isobornyl methacrylate (Tg 180 ° C.), adamantyl acrylate (Tg 115 ° C.), and methacrylic acid. Examples include adamantyl (Tg 141 ° C.) and the like. These may be used alone or in combination of two or more.

  Among the above hard monomers, methyl acrylate, methyl methacrylate and isobornyl acrylate are preferable from the viewpoint of exerting the performance of the hard monomer while preventing the adverse effect on other properties such as adhesiveness and transparency. In view of tackiness, methyl acrylate and methyl methacrylate are more preferable, and methyl methacrylate is particularly preferable.

  As said soft monomer, the acrylic acid alkylester which has a C2-C12 linear or branched alkyl group is mentioned preferably. For example, 2-ethylhexyl acrylate (Tg-70 ° C), n-butyl acrylate (Tg-54 ° C) and the like are preferably mentioned. These may be used alone or in combination of two or more.

  The (meth) acrylic acid ester polymer (A) preferably contains a reactive functional group-containing monomer as a monomer unit constituting the polymer. The reactive functional group derived from the reactive functional group-containing monomer is reacted with a crosslinking agent (D) described later to form a crosslinked structure (three-dimensional network structure), and a pre-curing pressure-sensitive adhesive having a desired cohesive force Is obtained.

  As a reactive functional group-containing monomer which the (meth) acrylic acid ester polymer (A) contains as a monomer unit constituting the polymer, a monomer having a hydroxyl group in the molecule (hydroxyl group-containing monomer), a carboxyl group in the molecule Preferred examples include a monomer having a group (carboxyl group-containing monomer) and a monomer having an amino group in the molecule (amino group-containing monomer). Among these, a hydroxyl group-containing monomer that is excellent in reactivity with the crosslinking agent (D) and moist heat and whitening resistance and has little adverse effect on the electrode is particularly preferable.

  Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, (meth And (meth) acrylic acid hydroxyalkyl esters such as 3-hydroxybutyl acrylate and 4-hydroxybutyl (meth) acrylate. Among them, 2-hydroxyethyl (meth) acrylate in terms of reactivity with the crosslinking agent (D) of the hydroxyl group in the (meth) acrylic acid ester polymer (A) and copolymerization with other monomers. Or 4-hydroxybutyl (meth) acrylate is preferred. These may be used alone or in combination of two or more.

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

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

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

  As the degree of whitening suppression, the haze value (measured according to JIS K7136: 2000) of the pressure-sensitive adhesive layer when it is returned to room temperature and normal humidity after being subjected to high temperature and high humidity conditions is 1.0% or less. Preferably, it is preferably 0.9% or less, and more preferably 0.8% or less. In addition, it is preferable that an adhesive layer has the above haze values also at the normal state. When the haze value is 1.0% or less, the transparency is very high, which is suitable for optical applications.

  However, when the hydrophilic group is present in the pressure-sensitive adhesive in a predetermined amount as described above, the pressure-sensitive adhesive can easily take in water, and migration easily occurs in the electrode in contact with the pressure-sensitive adhesive. However, by containing the silane coupling agent (B) having a mercapto group, the pressure-sensitive adhesive composition P according to the present embodiment can effectively prevent or suppress the occurrence of migration in the electrode in contact with it. it can.

  The (meth) acrylic acid ester polymer (A) preferably does not contain a carboxyl group-containing monomer as a monomer unit constituting the polymer, but is allowed to contain a predetermined amount. Since the carboxyl group is an acid component, migration of the target member is usually a concern. However, the pressure-sensitive adhesive obtained from the pressure-sensitive adhesive composition P containing the silane coupling agent (B) having a mercapto group has a carboxyl group. Even if it exists, it is because a migration preventing effect can be exhibited. Specifically, in the (meth) acrylic acid ester polymer (A), it is acceptable 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) acrylic acid ester polymer (A) may optionally contain other monomers as monomer units constituting the polymer. As the other monomers, monomers which do not contain a functional group having reactivity are preferable in order not to prevent the action of the reactive functional group-containing monomer. Examples of such other monomers include (meth) acrylic acid alkoxyalkyl esters such as methoxyethyl (meth) acrylate and ethoxyethyl (meth) acrylic acid, N, N-dimethylaminoethyl (meth) acrylic acid, (meth ) (Meth) acrylic acid ester having non-crosslinkable tertiary amino group such as N, N-dimethylaminopropyl acrylate and (meth) acryloyl morpholine, (meth) acrylamide, dimethylacrylamide, vinyl acetate, styrene etc. Be These may be used alone or in combination of two or more.

  The polymerization mode of the (meth) acrylic acid ester polymer (A) may be a random copolymer or a block copolymer.

  The lower limit value of the weight average molecular weight of the (meth) acrylic acid ester polymer (A) is preferably 200,000 or more, particularly preferably 300,000 or more, and further preferably 400,000 or more. When the lower limit value of the weight average molecular weight of the (meth) acrylic acid ester polymer (A) is not less than the above, the obtained pressure-sensitive adhesive becomes more excellent in the step following property under high temperature and high humidity conditions. In addition, the weight average molecular weight in this specification is the value of standard polystyrene conversion measured by the gel permeation chromatography (GPC) method.

  The upper limit value of the weight average molecular weight of the (meth) acrylic acid ester polymer (A) is preferably 1,000,000 or less, particularly preferably 900,000 or less, and further preferably 700,000 or less. preferable. When the upper limit value of the weight average molecular weight of the (meth) acrylic acid ester polymer (A) is not more than the above, the obtained pre-curing pressure-sensitive adhesive layer becomes more excellent in the step following property at the time of sticking.

  In the adhesive composition P, the (meth) acrylic acid ester polymer (A) may be used singly or in combination of two or more.

(2) Silane coupling agent having a mercapto group (B)
The silane coupling agent (B) having a mercapto group is composed of an organosilicon compound having at least one mercapto group and at least one alkoxysilyl group in the molecule. In consideration of the use of the obtained pressure-sensitive adhesive, the silane coupling agent (B) having a mercapto group is preferably light-transmitting, for example, substantially transparent.

  Specific examples of the silane coupling agent (B) having a mercapto group include mercapto group-containing low molecular weight silane cups such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, and 3-mercaptopropyldimethoxymethylsilane. Ring agents; mercapto group-containing silane compounds such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyldimethoxymethylsilane and the like, methyltriethoxysilane, ethyltriethoxysilane, methyltrimethoxysilane, Examples include mercapto group-containing oligomer type silane coupling agents such as co-condensates with alkyl group-containing silane compounds such as ethyltrimethoxysilane. Among them, mercapto group-containing oligomer type silane coupling agents which are excellent in migration prevention effect and good in workability are preferable, and in particular, a co-condensate of a mercapto group-containing silane compound and an alkyl group-containing silane compound is preferable. A cocondensate of propyltrimethoxysilane and methyltriethoxysilane is preferred. These may be used individually by 1 type and may be used in combination of 2 or more type.

  The lower limit of the mercapto group equivalent of the organosilicon compound constituting the silane coupling agent (B) having a mercapto group is preferably 100 g / mol or more, particularly preferably 120 g / mol or more, and more preferably 150 g. / Mol or more is preferable. By setting the lower limit as described above, the polarity difference from the (meth) acrylic acid ester polymer (A) is within an appropriate range, and the adhesive composition P of the silane coupling agent (B) is entered. The dispersability of can be made suitable.

  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 1000 g / mol or less, particularly preferably 800 g / mol or less, and further preferably 500 g / Mol or less is preferable. By setting the upper limit as described above, it is possible to prevent deterioration of optical characteristics due to phase separation from the (meth) acrylic acid ester polymer (A).

  Content of the silane coupling agent (B) which has a mercapto group in adhesive composition P is 0.01 mass part or more as a lower limit with respect to 100 mass parts of (meth) acrylic acid ester polymers (A) In particular, it is preferably 0.05 parts by mass or more, more preferably 0.1 parts by mass or more. The upper limit thereof is preferably 5 parts by mass or less, particularly preferably 1.5 parts by mass or less, and further preferably 1.0 parts by mass or less. When the content of the silane coupling agent (B) having a mercapto group is in the above range, the migration preventing effect becomes more excellent.

  In addition, the lower limit of the number of moles of mercapto group (the amount of mercapto group) in the silane coupling agent (B) per 100 g of the (meth) acrylic acid ester polymer (A) is preferably 0.01 mmol or more. In particular, 0.1 mmol or more is preferable, and 0.2 mmol or more is more preferable. The upper limit of the number of moles is preferably 30 mmol or less, particularly preferably 5 mmol or less, and more preferably 1.5 mmol or less. When the number of moles of the mercapto group of the silane coupling agent (B) relative to the (meth) acrylic acid ester polymer (A) is in the above range, the migration prevention effect can be further improved.

(3) Active energy ray curable component (C)
When the pressure-sensitive adhesive composition P contains the active energy ray-curable component (C), the pre-curing pressure-sensitive adhesive obtained by thermally crosslinking the pressure-sensitive adhesive composition P is activated when cured by irradiation with active energy rays. The energy ray curable component (C) is polymerized with each other, and the polymerized active energy ray curable component (C) is entangled with the crosslinked structure (three-dimensional network structure) of the (meth) acrylate polymer (A). Presumed. The pressure-sensitive adhesive having such a higher-order structure has a high cohesive force and a relatively high elastic modulus, and therefore has excellent blister resistance.

  The active energy ray curable component (C) is not particularly limited as long as it is a component which is cured by irradiation of active energy rays and the above effect can be obtained, and may be any of a monomer, an oligomer or a polymer, It may be a mixture of Among them, polyfunctional acrylate monomers having a molecular weight of less than 1000, which is excellent in compatibility with the (meth) acrylate polymer (A) and the like, can be preferably mentioned.

  As a polyfunctional acrylate monomer having a molecular weight of less than 1000, for example, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, polyethylene glycol di (Meth) acrylate, neopentyl glycol adipate di (meth) acrylate, hydroxypivalic acid neopentyl glycol di (meth) acrylate, dicyclopentanyl di (meth) acrylate, caprolactone modified dicyclopentenyl di (meth) acrylate, ethylene oxide modified Phosphoric acid di (meth) acrylate, di (acryloxyethyl) isocyanurate, allylated cyclohexyl di (meth) acrylate, ethoxylated bisphenol A diacrylate, 9,9-bi Bifunctional type such as [4- (2-acryloyloxyethoxy) phenyl] fluorene; trimethylolpropane tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, propionic acid modified dipentaerythritol tri (meth) acrylate, penta Trifunctional compounds such as erythritol tri (meth) acrylate, propylene oxide-modified trimethylolpropane tri (meth) acrylate, tris (acryloxyethyl) isocyanurate, ε-caprolactone modified tris- (2- (meth) acryloxyethyl) isocyanurate Type; tetrafunctional type such as diglycerin tetra (meth) acrylate, pentaerythritol tetra (meth) acrylate etc; pentafunctional type such as propionic acid modified dipentaerythritol penta (meth) acrylate And hexafunctional types such as dipentaerythritol hexa (meth) acrylate and caprolactone-modified dipentaerythritol hexa (meth) acrylate. Among these, pentaerythritol tri (meth) acrylate and ε-caprolactone-modified tris- (2- (meth) acryloxyethyl) isocyanurate are preferable from the viewpoint of blister resistance of the obtained pressure-sensitive adhesive. These may be used individually by 1 type and may be used in combination of 2 or more type.

  As the active energy ray-curable component (C), an active energy ray-curable acrylate oligomer can also be used. The acrylate oligomer preferably has a weight average molecular weight of 50,000 or less. Examples of such acrylate oligomers include polyester acrylates, epoxy acrylates, urethane acrylates, polyether acrylates, polybutadiene acrylates, silicone acrylates, and the like.

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

  In addition, as the active energy ray-curable component (C), an adduct acrylate polymer in which a group having a (meth) acryloyl group is introduced into a side chain can also be used. Such adduct acrylate polymers use a copolymer of (meth) acrylic acid ester and a monomer having a crosslinkable functional group in the molecule, and a part of the crosslinkable functional group of the copolymer is used. It can be obtained by reacting a compound having a (meth) acryloyl group and a group that reacts with a crosslinkable functional group.

  The weight average molecular weight of the adduct acrylate polymer is preferably about 50,000 to 900,000, and more preferably about 100,000 to 500,000.

  The active energy ray-curable component (C) can be used alone or in combination of the above-mentioned multifunctional acrylate monomers, acrylate oligomers and adduct acrylate polymers, or in combination of two or more. It can also be used in combination with other active energy ray-curable components.

  The content of the active energy ray-curable component (C) in the adhesive composition P is from the viewpoint of improving the cohesion of the obtained adhesive to make it excellent in blister resistance, (meth) acrylate ester weight It is preferable that it is 0.5 mass part or more as a lower limit with respect to 100 mass parts of unification | combination (A), It is more preferable that it is 1.0 mass part or more, It is especially that it is 3.0 mass part or more. preferable. On the other hand, the content is 50 parts by mass or less as the upper limit value from the viewpoint of preventing the active energy ray curable component (C) from phase separation with the (meth) acrylic acid ester polymer (A) Preferably, it is more preferably 20 parts by mass or less, and more preferably 12 parts by mass or less considering the viewpoint of further improving the blister resistance.

(4) Crosslinking agent (D)
The adhesive composition P preferably contains a crosslinking agent (D). The adhesive composition P contains a crosslinking agent (D) to crosslink the (meth) acrylic acid ester polymer (A) to form a three-dimensional network structure, and the cohesion of the resulting adhesive is more It is possible to improve the step following property under high temperature and high humidity conditions.

  The crosslinking agent (D) may be any one that reacts with the reactive group possessed by the (meth) acrylic acid ester polymer (A). For example, an isocyanate crosslinking agent, an epoxy crosslinking agent, an amine crosslinking agent, Melamine based crosslinking agents, aziridine based crosslinking agents, hydrazine based crosslinking agents, aldehyde based crosslinking agents, oxazoline based crosslinking agents, metal alkoxide based crosslinking agents, metal chelate based crosslinking agents, metal salt based crosslinking agents, ammonium salt based crosslinking agents, etc. It can be mentioned. When the (meth) acrylic acid ester polymer (A) contains a hydroxyl group-containing monomer as a monomer unit constituting the polymer, it is preferable to use an isocyanate-based crosslinking agent having excellent reactivity with the hydroxyl group. In addition, a crosslinking agent (D) can be used individually by 1 type or in combination of 2 or more types.

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

  The content of the crosslinking agent (D) in the adhesive composition P is preferably 0.001 parts by mass or more as a lower limit value with respect to 100 parts by mass of the (meth) acrylic acid ester polymer (A), In particular, it is preferably 0.01 parts by mass or more, and more preferably 0.02 parts by mass or more. The upper limit thereof is preferably 10 parts by mass or less, particularly preferably 5 parts by mass or less, and further preferably 1 part by mass or less.

  When the content of the cross-linking agent (D) is in the above range, the cohesive strength of the obtained pressure-sensitive adhesive becomes preferable, and the step following property of the pressure-sensitive adhesive under high temperature and high humidity conditions is further improved.

(5) Photopolymerization initiator (E)
The adhesive composition P may further contain a photopolymerization initiator (E) when ultraviolet light is used as an active energy ray irradiated to the pre-curing adhesive when curing the pre-curing adhesive. preferable. Thus, by containing the photopolymerization initiator (E), the active energy ray curable component (C) can be efficiently polymerized, and the polymerization curing time and the irradiation amount of the active energy ray can be reduced. it can.

  As such a photopolymerization initiator (E), for example, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylamino acetophenone, 2, 2-dimethoxyamine 2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-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-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-dimethylaminobenzoic acid ester, oligo [2-hydroxy-2-methyl-1 [4- (1-methylvinyl) phenyl] propanone], 2 4,6-trimethylbenzoyl-diphenyl-phosphine oxide and the like. These may be used alone or in combination of two or more.

  The content of the photopolymerization initiator (E) in the adhesive composition P is preferably 0.1 parts by mass or more as a lower limit with respect to 100 parts by mass of the active energy ray-curable component (C), In particular, it is preferably 1 part by mass or more. Moreover, it is preferable that it is 30 mass parts or less as an upper limit, and it is preferable that it is especially 10 mass parts or less.

(6) Various Additives In the pressure-sensitive adhesive composition P, various additives generally used in acrylic pressure-sensitive adhesives, for example, antistatic agents, tackifiers, antioxidants, ultraviolet light absorbers, and light stabilizers, as desired. An agent, a softening agent, a filler, a refractive index adjusting agent, a silane coupling agent other than the silane coupling agent (B) having a mercapto group, and the like can be added. However, since a rust preventive agent, especially a benzotriazole rust preventive agent has an action of inhibiting the crosslinking of the adhesive composition P, it is preferable not to contain it.

  The adhesive composition P represents a mixture of various components remaining in the pressure-sensitive adhesive layer as it is or in a reacted state, and is a component to be removed in a drying step or the like, for example, polymerization described later. The solvent and the dilution solvent are not included in the adhesive composition P.

(7) Production of adhesive composition The adhesive composition P produces a (meth) acrylic acid ester polymer (A), and the obtained (meth) acrylic acid ester polymer (A) and a mercapto group While mixing the silane coupling agent (B) having and the active energy ray-curable component (C), if desired, it is produced by adding a crosslinking agent (D), a photopolymerization initiator (E) and an additive. be able to.

  The (meth) acrylic acid ester polymer (A) can be produced by polymerizing a mixture of monomer units constituting the polymer by an ordinary radical polymerization method. The polymerization of the (meth) acrylic acid ester polymer (A) can be carried out by solution polymerization or the like, using a polymerization initiator, if desired. As a polymerization solvent, ethyl acetate, n-butyl acetate, isobutyl acetate, toluene, acetone, hexane, methyl ethyl ketone etc. are mentioned, for example, You may use 2 or more types together.

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

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

  In addition, in the said superposition | polymerization process, the weight average molecular weight of the polymer obtained can be adjusted by mix | blending chain transfer agents, such as 2-mercaptoethanol.

  When the (meth) acrylic acid ester polymer (A) is obtained, the solution of the (meth) acrylic acid ester polymer (A) is added with a silane coupling agent (B) having a mercapto group, an active energy ray curable component ( C), and, optionally, a crosslinker (D), a photopolymerization initiator (E), an additive and a diluting solvent are added, and the adhesive composition P (coating solution diluted with solvent by thorough mixing) Get).

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

  The concentration / viscosity of the coating solution thus prepared is not particularly limited as long as it can be coated, and can be appropriately selected depending on the situation. For example, it dilutes so that the density | concentration of the adhesive composition P may be 10-40 mass%. In addition, when obtaining a coating solution, addition of a dilution solvent etc. is not a necessary condition, and if a viscosity etc. which can be coated with the adhesive composition P are not necessary, a dilution solvent does not need to be added. In this case, the adhesive composition P is a coating solution in which the polymerization solvent of the (meth) acrylic acid ester polymer (A) is used as a dilution solvent as it is.

[Adhesive sheet]
As shown in FIG. 1, the pressure-sensitive adhesive sheet 1 according to this embodiment includes two release sheets 12a and 12b and the two release sheets 12a so as to be in contact with the release surfaces of the two release sheets 12a and 12b. , 12b, and the pressure-sensitive adhesive layer 10 before curing. However, the release sheets 12a and 12b in the pressure-sensitive adhesive sheet 1 are not essential components, and are peeled and removed when the pressure-sensitive 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 even if it does not perform peeling processing. .

(1) Pre-curing pressure-sensitive adhesive layer The pre-curing pressure-sensitive adhesive layer 10 is a layer formed by thermally cross-linking the above-mentioned pressure-sensitive adhesive composition P, and is a stage before curing by irradiation with active energy rays. The lower limit of the thickness of the pressure-sensitive adhesive layer 10 before curing (measured according to JIS K7130) is preferably 10 μm or more, particularly preferably 25 μm or more, and more preferably 50 μm or more. . When the lower limit value of the thickness of the pre-curing pressure-sensitive adhesive layer 10 is the above or more, the pressure-sensitive adhesive layer obtained by curing the pre-curing pressure-sensitive adhesive layer 10 sufficiently exhibits excellent adhesive force. The upper limit of the thickness of the pressure-sensitive adhesive layer 10 before curing is preferably 300 μm or less, particularly preferably 250 μm or less, and further preferably 100 μm or less. When the upper limit value of the thickness of the pre-curing pressure-sensitive adhesive layer 10 is equal to or less than the above, the processability is improved. The pressure-sensitive adhesive layer 10 before curing may be formed as a single layer, or may be formed by laminating a plurality of layers.

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

  It is preferable that the peeling process (especially the surface which contact | connects the adhesive layer 10 before hardening) of the said peeling sheet 12a, 12b is given the peeling process. Examples of the release agent used for the release treatment include alkyd, silicone, fluorine, unsaturated polyester, polyolefin, and wax release agents. Of the release sheets 12a and 12b, one release sheet is preferably a heavy release release sheet having a high release force, and the other release sheet is preferably a light release release sheet having a low release force.

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

(3) Production of pressure-sensitive adhesive sheet As one production example of the pressure-sensitive adhesive sheet 1, a coating liquid of the above-mentioned pressure-sensitive adhesive composition P is applied to the release surface of one release sheet 12a (or 12b), and heat treatment is performed for adhesion. After heat-crosslinking property composition P and forming a coating layer, the peeling surface of the other peeling sheet 12b (or 12a) is piled up on the coating layer. When a curing period is required, a curing period is set, and when the curing period is unnecessary, the coating layer becomes the pre-curing pressure-sensitive adhesive layer 10 as it is. Thus, the pressure-sensitive adhesive sheet 1 is obtained. The heat treatment can be combined with the drying treatment at the time of volatilizing the diluted solvent and the like of the applied adhesive composition P.

  When heat-processing, it is preferable that heating temperature is 50-150 degreeC, and it is preferable that it is especially 70-120 degreeC. The heating time is preferably 30 seconds to 10 minutes, particularly preferably 50 seconds to 2 minutes. When providing a curing period, it is preferable that it is about 1 to 2 weeks, for example at normal temperature (for example, 23 degreeC, 50% RH) as the conditions.

  For example, a bar coating method, a knife coating method, a roll coating method, a blade coating method, a die coating method, a gravure coating method, or the like can be used as a method for applying the coating solution of the adhesive composition P.

  As another manufacturing example of the adhesive sheet 1, the coating liquid of the said adhesive composition P is apply | coated to the peeling surface of one peeling sheet 12a, heat processing is performed, the adhesive composition P is bridge | crosslinked, and an application layer To obtain a release sheet 12a with a coating layer. Moreover, the coating liquid of the said adhesive composition P is apply | coated to the peeling surface of the other peeling sheet 12b, heat processing is performed, the adhesive composition P is bridge | crosslinked, an application layer is formed, and an application layer is attached. A release sheet 12b is obtained. Then, the release sheet 12a with the application layer and the release sheet 12b with the application layer are pasted together so that the two application layers are in contact with each other. When the curing period is required, the curing period is set, and when the curing period is unnecessary, the laminated coated layer described above becomes the pre-curing pressure-sensitive adhesive layer 10 as it is. Thus, the pressure-sensitive adhesive sheet 1 is obtained. According to this production example, even when the pre-curing pressure-sensitive adhesive layer 10 is thick, stable production can be achieved.

(4) Gel fraction The lower limit value of the gel fraction of the pre-curing pressure-sensitive adhesive formed by thermally crosslinking the adhesive composition P is preferably 20% or more, particularly preferably 30% or more, and further, Is preferably 40% or more. When the lower limit value of the gel fraction of the pre-curing pressure-sensitive adhesive is at least the above, the cohesion of the pressure-sensitive adhesive which is cured by irradiation with active energy rays becomes high, and the blister resistance becomes more excellent. The upper limit of the gel fraction is preferably 90% or less, particularly preferably 80% or less, and more preferably 75% or less. When the upper limit value of the gel fraction of the pre-curing adhesive is not more than the above, the pre-curing adhesive layer 10 does not become too hard, and the step following property at the time of sticking becomes excellent.

  On the other hand, the lower limit of the gel fraction of the pressure-sensitive adhesive obtained by curing the pre-curing pressure-sensitive adhesive by irradiation with active energy rays is preferably 50% or more, particularly preferably 60% or more, It is preferable that it is 70% or more. When the lower limit of the gel fraction of the pressure-sensitive adhesive is not less than the above, the cohesive force of the pressure-sensitive adhesive is increased, and the blister resistance is more excellent. The upper limit of the gel fraction is preferably 99% or less, particularly preferably 96% or less, and more preferably 94% or less. When the upper limit value of the gel fraction of the pressure-sensitive adhesive is not more than the above, it is possible to maintain an appropriate pressure-sensitive adhesive force and maintain a good blister performance. In addition, the measuring method of the gel fraction of an adhesive before hardening and an adhesive is as showing to the test example mentioned later.

(5) Adhesive strength The lower limit of the adhesive strength of the pressure-sensitive adhesive sheet 1 according to this embodiment to soda lime glass is preferably 5 N / 25 mm or more, particularly preferably 7 N / 25 mm or more, and more preferably 10 N / It is preferable that it is 25 mm or more. When the lower limit value of the adhesive strength of the pressure-sensitive adhesive sheet 1 is not less than the above, it is possible to effectively prevent the release sheet from being peeled off during storage or peeling between the adherend and the like in the transport process. On the other hand, the upper limit of the adhesive strength is not particularly limited, but it is preferably 50 N / 25 mm or less in consideration of ease of peeling from the pre-curing pressure-sensitive adhesive layer 10 of the release sheets 12a and 12b during use, In particular, it is preferably 30 N / 25 mm or less. Furthermore, if reworkability is also taken into consideration, it is preferably 26 N / 25 mm or less. In that case, even when a bonding mistake occurs, the display member constituting member can be easily reused.

  The above-mentioned adhesive strength basically refers to the adhesive strength measured by a 180-degree peeling method according to JIS Z0237: 2009. The measurement sample is 25 mm wide and 100 mm long, and the measurement sample is attached to an adherend. The sample is pressurized at 0.5 MPa and 50 ° C. for 20 minutes and then left at normal pressure, 23 ° C. and 50% RH for 24 hours, and then measured at a peeling speed of 300 mm / min.

  The lower limit of the adhesive strength of the pressure-sensitive adhesive sheet to soda lime glass in the case where the pressure-sensitive adhesive layer 10 of the pressure-sensitive adhesive sheet 1 according to this embodiment is cured by irradiation with active energy rays to form the pressure-sensitive adhesive layer is It is preferably 5 N / 25 mm or more, particularly preferably 7 N / 25 mm or more, and further preferably 10 N / 25 mm or more. When the lower limit value of the adhesive strength of the pressure-sensitive adhesive sheet 1 is equal to or higher than the above value, it becomes more excellent in blister resistance. On the other hand, the upper limit value of the adhesive strength is not particularly limited, but is usually 50 N / 25 mm or less.

  The above-mentioned adhesive strength basically refers to the adhesive strength measured by a 180-degree peeling method according to JIS Z0237: 2009. The measurement sample is 25 mm wide and 100 mm long, and the measurement sample is attached to an adherend. After being pressurized at 50 ° C for 20 minutes, the pre-curing pressure-sensitive adhesive layer is cured by irradiation with active energy rays to form a pressure-sensitive adhesive layer, and then under normal pressure, 23 ° C, 50% RH conditions After leaving to stand for 24 hours, it shall be measured at a peeling speed of 300 mm / min.

[Display body]
The display body according to the present embodiment includes a first display body constituent member having a step on at least a surface to be bonded, a second display body constituent member, a first display body constituent member, and a second display body constituent member. And a pressure-sensitive adhesive layer for bonding the display body constituent members to each other. A 1st display body structural member and / or a 2nd display body structural member have an electrode in the surface at the side (adhesive layer side) to be bonded at least. As a preferred configuration, the second display member constituting member has an electrode on at least the surface to be bonded.

  The pressure-sensitive adhesive layer is obtained by curing the aforementioned pre-curing pressure-sensitive adhesive layer by irradiation with active energy rays. Here, active energy rays refer to those having energy quanta among electromagnetic waves or charged particle beams, and specific examples include ultraviolet rays and electron beams. Among the active energy rays, ultraviolet rays which are easy to handle are particularly preferable.

Irradiation with ultraviolet rays can be performed by a high-pressure mercury lamp, a fusion H lamp, a xenon lamp, or the like, and the irradiation amount of ultraviolet rays is preferably about 50 to 1000 mW / cm ^{2 in} illuminance. Further, the light quantity is preferably 50~10000mJ / cm ^2, more preferably 80~5000mJ / cm ^2, and particularly preferably 200~2000mJ / 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 dose of the electron beam is preferably about 10 to 1000 krad.

  Irradiation of the active energy ray to the pre-curing pressure-sensitive adhesive layer is performed by bonding the first display body constituting member and the second display body constituting member to each other by the pre-curing pressure-sensitive adhesive layer, It is preferable to carry out through the member which permeate | transmits an active energy ray among 2nd display body structural members.

  When active energy rays are irradiated to the pre-curing pressure-sensitive adhesive layer, the active energy ray-curable component (B) is polymerized and cured. The pressure-sensitive adhesive layer obtained by curing the pressure-sensitive adhesive layer before curing by irradiation of active energy rays has very excellent blister resistance.

  Examples of the display include a liquid crystal (LCD) display, a light emitting diode (LED) display, an organic electroluminescence (organic EL) display, an electronic paper, and the like, and may be a touch panel. Moreover, as a display body, you may be the member which comprises those one part.

  It is preferable that a 1st display body structural member is a protection panel which consists of a laminated body containing them other than a glass plate, a plastic plate, etc. The first display member constituting member preferably has a step on the surface on the adhesive layer side, and specifically, preferably has a step due to the printing layer. The printing layer is generally formed in a frame shape.

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

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

  In addition, various functional layers (electrode layer, silica layer, hard coat layer, antiglare layer, etc.) may be provided on one side or both sides of the above glass plate or plastic plate, and an optical member is laminated. May be.

  The material which comprises a printing layer is not specifically limited, The well-known material for printing is used. The lower limit of the thickness of the print 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 . When the lower limit value is equal to or more than the above, the concealing property such as making the electric wiring invisible from the viewer side can be sufficiently ensured. The upper limit is preferably 50 μm or less, more preferably 35 μm or less, particularly preferably 25 μm or less, and still more preferably 20 μm or less. When the upper limit value is less than or equal to the above, deterioration in the step followability of the pressure-sensitive adhesive layer with respect to the print layer can be prevented.

  The second display member constituting member is an optical member to be attached to the first display member constituting member, a display member module (for example, a liquid crystal (LCD) module, a light emitting diode (LED) module, an organic electroluminescence (organic EL) Module), an optical member as a part of the display module, or a laminate including the display module, and preferably has an electrode on at least the surface of the pressure-sensitive adhesive layer.

  As said optical member, an electrode film, a transparent conductive film, a film sensor, a metal nanowire film, a wire grid polarization film etc. are mentioned, for example.

  Examples of the electrode include metal electrodes (including mesh-like and grid-like ones) made of copper, silver and the like, and transparent conductive films (including those patterned) made of tin-doped indium oxide (ITO) and the like. Be As described above, among the above electrodes, a metal electrode mainly composed of an unoxidized metal, specifically, a metal electrode made of copper or silver is preferable.

  As an example of the display body according to the present embodiment, a capacitive touch panel 2 is shown in FIG. The touch panel 2 includes a display module 3, a first film sensor 5 a laminated on the display module 3 via the adhesive layer 4, and a second film sensor 5 a laminated on the display module 3 via the first adhesive layer 11. A film sensor 5b and a cover member 6 laminated thereon via the second pressure-sensitive adhesive layer 11 are configured. A printed layer 7 is formed on the surface of the cover material 6 on the second pressure-sensitive adhesive layer 11 side, and therefore there is a step due to the presence or absence of the printed layer 7. In the present embodiment, the cover material 6 corresponds to the first display member constituting member, and the second film sensor 5b corresponds to the second display member constituting member.

  The first pressure-sensitive adhesive layer 11 and the second pressure-sensitive adhesive layer 11 in the present embodiment are both irradiated with active energy rays before curing of the pressure-sensitive adhesive sheet 1 in consideration of their migration preventing effect. It shall be hardened by. However, the present invention is not limited thereto, and the first pressure-sensitive adhesive layer 11 may be formed of another pressure-sensitive adhesive or a pressure-sensitive adhesive sheet. Examples of the pressure-sensitive adhesive in this case include acrylic pressure-sensitive adhesives, rubber-based pressure-sensitive adhesives, silicone-based pressure-sensitive adhesives, urethane-based pressure-sensitive adhesives, polyester-based pressure-sensitive adhesives, and polyvinyl ether-based pressure-sensitive adhesives. Among them, acrylic pressure-sensitive adhesives are preferable. .

  The pressure-sensitive adhesive layer 4 may be formed by the pressure-sensitive adhesive layer 10 before curing of the pressure-sensitive adhesive sheet 1, or may be formed by another pressure-sensitive adhesive or pressure-sensitive adhesive sheet. In the latter case, the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer 4 includes an acrylic pressure-sensitive adhesive, a rubber-based pressure-sensitive adhesive, a silicone-based pressure-sensitive adhesive, a urethane-based pressure-sensitive adhesive, a polyester-based pressure-sensitive adhesive, and a polyvinyl ether-based pressure-sensitive adhesive. Among them, acrylic pressure-sensitive adhesives are preferred.

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

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

  One of the electrode 52 of the first film sensor 5a and the electrode 52 of the second film sensor 5b normally constitutes a circuit pattern in the X-axis direction, and the other constitutes a circuit pattern in the Y-axis direction.

  The electrode 52 of the second film sensor 5b in the present embodiment is located above the second film sensor 5b in FIG. On the other hand, although the electrode 52 of the 1st film sensor 5a is located in the upper side of the 1st film sensor 5a in FIG. 2, it is not limited to this, The lower side of the 1st film sensor 5a May be located.

An example of a method of manufacturing the touch panel 2 will be described below.
As the pressure-sensitive adhesive sheet 1, a first pressure-sensitive adhesive sheet 1 and a second pressure-sensitive adhesive sheet 1 are prepared. One release sheet 12a is peeled from the first pressure-sensitive adhesive sheet 1, and the exposed pre-curing pressure-sensitive adhesive layer 10 (first pre-curing pressure-sensitive adhesive layer 10) is in contact with the electrode 52 of the first film sensor 5a. The first film sensor 5a is bonded. Further, one release sheet 12a is peeled from the second pressure-sensitive adhesive sheet 1, and the exposed pre-curing pressure-sensitive adhesive layer 10 (second pre-curing pressure-sensitive adhesive layer 10) is in contact with the electrode 52 of the second film sensor 5b. Thus, it bonds with the said 2nd film sensor 5b.

  Then, the other release sheet 12b in the first adhesive sheet is peeled off, and the exposed first pre-curing adhesive layer 10 is laminated with the second pre-curing adhesive layer 10 in the second film sensor 5b. The two are bonded so as to be in contact with the surface (the exposed surface of the base film 51 of the first film sensor 5 b) on the opposite side to the other side. Thereby, a laminate is obtained in which the release sheet 12b, the second pressure-sensitive adhesive layer 10 before curing, the second film sensor 5b, the first pressure-sensitive adhesive layer 10 before curing and the first film sensor 5a are sequentially stacked. Be

  Next, the pressure-sensitive adhesive layer 4 provided on the release sheet is bonded to the surface on the first film sensor 5a side of the laminate (the exposed surface of the base film 51 of the first film sensor 5a). Subsequently, the release sheet 12 b is peeled off from the laminate, and the printed layer 7 side of the cover material 6 is in contact with the second pre-curing pressure-sensitive adhesive layer 10 with respect to the exposed second pre-curing pressure-sensitive adhesive layer 10. The said cover material 6 is bonded together. At this time, since the second pre-curing pressure-sensitive adhesive layer 10 is excellent in the step following property at the time of sticking, generation of a gap or floating in the vicinity of the step due to the printing layer 7 is suppressed. By the above bonding, the cover 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, the adhesive layer 4 and the release sheet Are sequentially laminated.

  Next, the second pre-curing pressure-sensitive adhesive layer 10 and the first pre-curing pressure-sensitive adhesive layer 10 are irradiated with active energy rays from any side of the above-mentioned construct, preferably from the cover material 6 side, The second pre-curing pressure-sensitive adhesive layer 10 and the first pre-curing pressure-sensitive adhesive layer 10 are cured to form a second pressure-sensitive adhesive layer 11 and a first pressure-sensitive adhesive layer 11, respectively.

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

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

  In addition, since the pressure-sensitive adhesive layer 11 is excellent in step followability even under high temperature and high humidity conditions, even when the touch panel 2 is exposed to the high temperature and high humidity conditions for a predetermined time, The occurrence of floating, peeling and the like is effectively suppressed.

  Furthermore, even if the touch panel 2 is placed under a high temperature and high humidity condition and outgas is generated from the cover material 6, the second film sensor 5b, or the first film sensor 5a, the pressure-sensitive adhesive layer 11 is excellent in blister resistance. Therefore, the occurrence of blisters such as air bubbles, floating, and peeling is suppressed at the interface between the pressure-sensitive adhesive layer 11 and the cover member 6, the second film sensor 5b, or the first film sensor 5a.

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

  For example, one of the release sheets 12a and 12b in the pressure-sensitive adhesive sheet 1 may be omitted.

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

Example 1
1. Preparation of (meth) acrylic acid ester copolymer 60 parts by mass of 2-ethylhexyl acrylate, 20 parts by mass of methyl methacrylate and 20 parts by mass of 2-hydroxyethyl acrylate are copolymerized to obtain (meth) acrylic acid ester polymer (A) was prepared. When the molecular weight of this (meth) acrylic acid ester polymer (A) was measured by the method mentioned later, it was 600,000 of weight average molecular weight (Mw).

2. Preparation of Adhesive Composition As (meth) acrylic acid ester polymer (A) 100 parts by mass (in terms of solid content; the same applies hereinafter) obtained in Step 1 above, and a silane coupling agent (B) having a mercapto group Of 2-mercaptopropyltrimethoxysilane and methyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name “X-41-1810”, oligomer type, mercapto group equivalent: 450 g / mol) 0.20 mass Part and ε-caprolactone-modified tris- (2-acryloxyethyl) isocyanurate (product name “NK Ester A-9300-1CL” manufactured by Shin-Nakamura Chemical Co., Ltd.) as an active energy ray-curable component (C) 5 parts by mass and trimethylolpropane-modified tolylene diisocyanate as a crosslinking agent (D) L ") 0.23 parts by mass, and as a photopolymerization initiator (E), a mixture of benzophenone and 1-hydroxycyclohexyl phenyl ketone in a mass ratio of 1: 1 (BASF, product name" Irgacure 500 ") 0.25 part by mass was mixed, sufficiently stirred, and diluted with methyl ethyl ketone to obtain a coating solution of an adhesive composition having a solid content concentration of 36% by mass.

Here, each composition (solid content conversion value) of the adhesive composition at the time of setting a (meth) acrylic acid ester polymer (A) to 100 mass parts (solid content conversion value) is shown in Table 1. Details of the abbreviations and the like described in Table 1 are as follows.
[(Meth) acrylic acid ester polymer (A)]
2EHA: 2-ethylhexyl acrylate MMA: methyl methacrylate HEA: 2-hydroxyethyl acrylate
[Silane coupling agent having mercapto group (B)]
X-41-1810: Co-condensation product of 3-mercaptopropyltrimethoxysilane and methyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name “X-41-1810”, oligomer type, mercapto group equivalent: 450 g / mol) )
KBM-803: 3-mercaptopropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name “KBM-803”, low molecular type, mercapto group equivalent: 196.4 g / mol)
[Other silane coupling agents]
KBM-403: 3-glycidoxypropyltrimethoxysilane (Shin-Etsu Silicone Co., Ltd., trade name "KBM-403", low molecular weight type)
KBE-9007: 3-isocyanatopropyltriethoxysilane (manufactured by Shin-Etsu Silicone, trade name “KBE-9007”, low molecular weight type)
[Active energy ray-curable component (C)]
NK ester A-9300-1CL: ε-caprolactone-modified tris- (2-acryloxyethyl) isocyanurate (manufactured by Shin-Nakamura Chemical Co., Ltd., product name “NK ester A-9300-1CL”)
NK ester A-TMM-3L: pentaerythritol triacrylate (triester 55% by mass) (product of Shin-Nakamura Chemical Co., Ltd., product name "NK ester A-TMM-3L")

3. Manufacture of an adhesive sheet The application | coating solution of the adhesive composition obtained at the said process 2 is a heavy peeling type release sheet (the product name "SP-PET382150 made from a Lintec company) which peeled one side of the polyethylene terephthalate film with the silicone type release agent. After coating with a knife coater on a release-treated surface having a thickness of 38 μm, the coated layer (thickness: 25 μm) was formed by heat treatment at 90 ° C. for 1 minute. Similarly, the light release release sheet (product name “SP-PET 382120”, manufactured by Lintec Co., Ltd.) obtained by removing one surface of the polyethylene terephthalate film with a silicone-based release agent from the coating solution of the adhesive composition obtained in Step 2 above. ) Was applied with a knife coater, followed by heat treatment at 90 ° C. for 1 minute to form a coating layer (thickness: 25 μm).

  Then, the heavy release type release sheet with the coated layer obtained above and the light release type release sheet with the coated layer obtained above are pasted so that both coated layers are in contact with each other, and 23 ° C. By curing for 7 days under the conditions of 50% RH, a pressure-sensitive adhesive sheet was produced, which was composed of a heavy release type release sheet / pressure-sensitive adhesive layer before curing (thickness: 50 μm) / light release type release sheet.

[Examples 2 to 10, Comparative Examples 1 to 10]
Types and ratios of silane coupling agents (silane coupling agents having a mercapto group (B) and other silane coupling agents), types and ratios of active energy ray-curable components (C), ratios of crosslinking agents (D) And a pressure-sensitive adhesive sheet were produced in the same manner as in Example 1 except that the proportion of the photopolymerization initiator (E) was changed as shown in Table 1. As Comparative Examples 7 to 10, N, N-bis (2-ethylhexyl)-(4 or 5) -methyl-1H-benzotriazole-1-methylamine (manufactured by BASF, trade name “N”, as a rust inhibitor. IRGMET 39 ") was blended into the adhesive composition in the proportions shown in Table 1. In addition, the adhesive compositions of Comparative Examples 1 to 10 are non-curable with active energy rays, and those obtained by thermally cross-linking the adhesive composition generally become an adhesive, but for convenience, a layer made of the adhesive May also be referred to as “pre-curing pressure-sensitive adhesive layer”.

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

Test Example 1 (Measurement of Gel Fraction)
The pressure-sensitive adhesive sheets obtained in Examples and Comparative Examples were cut into a size of 80 mm × 80 mm, the pressure-sensitive adhesive layer before curing was wrapped in a polyester mesh (mesh size 200), and the mass was weighed with a precision balance. By subtracting the mass of the mesh alone, the mass of the pre-curing adhesive alone was calculated. The mass at this time is M1.

  Next, the pre-curing adhesive wrapped in the polyester mesh was immersed in ethyl acetate for 24 hours at room temperature (23 ° C.). Thereafter, the pressure-sensitive adhesive before curing was taken out, air-dried for 24 hours in an environment of a temperature of 23 ° C. and a relative humidity of 50%, and further dried in an oven at 80 ° C. for 12 hours. After drying, the mass was weighed with a precision balance, and the mass of the pressure-sensitive adhesive before curing was calculated by subtracting the mass of the mesh alone. The mass at this time is M2. The gel fraction (%) is represented by (M2 / M1) × 100. The results are shown in Table 2.

Further, with respect to the pre-curing pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet obtained in the examples, it was passed through a light-release type release sheet by an ultraviolet irradiation device (product name “Igrantage ECS-401GX type” manufactured by Eye Graphics). It was irradiated with ultraviolet light under the following conditions to cure the pressure-sensitive adhesive layer before curing to form a pressure-sensitive adhesive layer. About this adhesive layer, it carried out similarly to the said adhesive layer before hardening, and measured the gel fraction (%). The results are shown in Table 2.
[UV irradiation conditions]
-Light source: High pressure mercury lamp-Light quantity: 1000 mJ / cm ²
-Illuminance: 200mW / cm ²

[Test Example 2] (Measurement of Adhesive Strength)
The light release type release sheet was peeled from the pressure sensitive adhesive sheets obtained in Examples and Comparative Examples, and the exposed pre-cured pressure sensitive adhesive layer was replaced with a polyethylene terephthalate (PET) film (product name “PET” manufactured by Toyobo Co., Ltd.). A4300 ”, thickness: 100 μm) was bonded to an easy-adhesion layer to obtain a laminate of a heavy release type 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 this was used as a sample.

  Made of Kurihara Seisakusho after peeling the heavy release release sheet from the above sample and pasting the exposed pre-curing adhesive layer on soda lime glass (made by Nippon Sheet Glass Co., Ltd.) in an environment of 23 ° C. and 50% RH. The autoclave was pressurized at 0.5 MPa and 50 ° C. for 20 minutes. Then, after being allowed to stand for 24 hours under the conditions of 23 ° C. and 50% RH, using a tensile tester (Orientec, Tensilon), the adhesive strength (N / 25 mm). Conditions other than those described here were measured according to JIS Z 0237: 2009. The results are shown in Table 2.

  In addition, as described above, the above sample (only the example) is attached to soda lime glass and pressurized at 0.5 MPa and 50 ° C. for 20 minutes in an autoclave manufactured by Kurihara Seisakusho Co., Ltd. The agent layer was irradiated with ultraviolet light under the same ultraviolet irradiation conditions as in Test Example 1 to cure the pressure-sensitive adhesive layer before curing to form a pressure-sensitive adhesive layer. About the sample which has this adhesive layer, it carried out similarly to the above, and measured adhesive force (N / 25mm). The results are shown in Table 2.

[Test Example 3] (Evaluation of migration prevention effect)
(1) Fabrication of a wiring board Copper of a copper clad laminate (product name “Nikaflex” manufactured by Nikkan Kogyo Co., Ltd.) obtained by laminating a copper foil (thickness: 18 μm) and a polyethylene terephthalate film (thickness: 50 μm) An etching resist pattern was printed on the foil surface by screen printing. Thereafter, unnecessary copper foil was removed by etching to form a comb electrode. The line width of each electrode was 300 μm, and the gap between the electrodes was 50 μm.

(2) Evaluation of migration prevention effect The lightly peelable release sheet was peeled off from the pressure sensitive adhesive sheets obtained in Examples and Comparative Examples, and the exposed pre-curing pressure sensitive adhesive layer was replaced with a polyethylene terephthalate (PET) film having an easy adhesion layer ( It was bonded to an easy-adhesion layer of Toyobo Co., Ltd., product name “PET A4300”, thickness: 100 μm) to obtain a laminate of a heavy release type release sheet / adhesive layer before curing / PET film. Next, the heavy release type release sheet was peeled off from the laminate, and the exposed pre-curing pressure-sensitive adhesive layer was attached onto the comb electrode.

  The pre-curing pressure-sensitive adhesive layer (only the examples) was irradiated with ultraviolet light under the same ultraviolet irradiation conditions as in Test Example 1 through the PET film to cure the pre-curing pressure-sensitive adhesive layer to form a pressure-sensitive adhesive layer.

The sample obtained as described above was allowed to stand under moist heat conditions of 85 ° C. and 85% RH, and in this state, a voltage of 5 V was applied between the electrodes to conduct a migration test. The comb electrode was observed with an optical microscope (magnification: 10 times) 8 hours, 24 hours and 48 hours after the start of the test, and the migration prevention effect was evaluated based on the evaluation criteria shown below. The results are shown in Table 2.
◎: Dissolution of electrode (positive electrode) and formation of dendrite in electrode (negative electrode) are not observed at all.
Good: Dissolution was observed only at the end of the electrode (positive electrode), and no formation of dendrite in the electrode (negative electrode) was observed.
X: Dissolution of the electrode (positive electrode) and formation of dendrite in the electrode (negative electrode) are observed.
A reference image of the evaluation criteria is shown in FIG.

[Test Example 4] (Evaluation of step following ability)
(A) Preparation of sample for evaluation On the surface of a glass plate (manufactured by NSG Precision, product name “Corning Glass Eagle XG”, length 90 mm × width 50 mm × thickness 0.5 mm), an ultraviolet curable ink (made by Teikoku Ink, The product name “POS-911 Black”) was screen-printed in a frame shape (outside: vertical 90 mm × width 50 mm, width 5 mm) so that the coating thickness was any one of 5 μm, 10 μm, 15 μm, and 20 μm. Next, irradiation with ultraviolet rays (80 W / cm ² , ^two metal halide lamps, lamp height of 15 cm, belt speed of 10 to 15 m / min) is performed to cure the printed ultraviolet curable ink, and a level difference due to printing (level difference) A stepped glass plate having a length of 5 μm, 10 μm, 15 μm or 20 μm) was produced.

  A light-peelable release sheet is peeled off from the pressure-sensitive adhesive sheet obtained in Examples and Comparative Examples, and the exposed uncured pressure-sensitive adhesive layer is a polyethylene terephthalate (PET) film (PET, A4300, manufactured by Toyobo Co., Ltd.). : 100 μm) of the easily adhesive layer. Next, the heavy release release sheet was peeled off to expose the pre-curing pressure-sensitive adhesive layer. And using the laminator (The product name "LPD3214" by the Fuji plastic company), the said laminated body was laminated | stacked on each glass plate with a level | step difference so that the adhesive layer before hardening might cover the printing surface of frame shape.

  The pre-curing pressure-sensitive adhesive layer (only the examples) was irradiated with ultraviolet light under the same ultraviolet irradiation conditions as in Test Example 1 through the PET film to cure the pre-curing pressure-sensitive adhesive layer to form a pressure-sensitive adhesive layer.

(B) Evaluation of evaluation sample After the evaluation sample obtained as described above is autoclaved at 50 ° C. and 0.5 MPa for 30 minutes, 24 at normal pressure, 23 ° C. and 50% RH. I left for a while. Subsequently, it was stored for 72 hours under 85 ° C. and 85% RH durability conditions. Thereafter, the pressure-sensitive adhesive layer (particularly in the vicinity of the step due to the printing layer) was visually confirmed, and the step following property was evaluated according to the following criteria. The results are shown in Table 2.
(Double-circle): There was no bubble and no float.
○: Less than 10 bubbles were observed near the step.
X: There were bubbles and / or floats.

[Test Example 5] (Evaluation of blister resistance)
The pre-curing pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheets obtained in Examples and Comparative Examples was prepared by using a polyethylene terephthalate (PET) film (made by Oike Kogyo Co., Ltd.) with a transparent conductive film made of tin-doped indium oxide (ITO) on one side. The film was sandwiched between a transparent conductive film having a thickness of 125 μm and a polycarbonate plate (manufactured by Mitsubishi Gas Chemical Company, product name “Iupilon sheet MR58”, thickness: 1 mm) to obtain a laminate.

  The obtained laminate was autoclaved for 30 minutes at 50 ° C. and 0.5 MPa. And with respect to the laminated body of an Example, an ultraviolet-ray was irradiated on the same ultraviolet irradiation conditions as Test example 1 through a PET film, the adhesive layer before hardening was hardened, and it was set as the adhesive layer.

The sample obtained as described above was left at normal pressure, 23 ° C., 50% RH for 15 hours, and then stored for 72 hours under high temperature and high humidity conditions of 85 ° C., 85% RH. Thereafter, air bubbles, floating or peeling at the interface between the pressure-sensitive adhesive layer and the adherend were visually confirmed, and the blister resistance was evaluated according to the following criteria. The results are shown in Table 2.
... ... There were no bubbles, floating and peeling.
○: Only bubbles with a diameter of 0.2 mm or less were generated.
X ... air bubbles having a diameter of more than 0.2 mm, floating or peeling occurred.

[Test Example 6] (Evaluation of resistance to moist heat whitening)
The pressure-sensitive adhesive layer before curing of the pressure-sensitive adhesive sheet obtained in Examples or Comparative Examples was sandwiched between two non-alkali glass sheets having a thickness of 1.1 mm to obtain a laminate. And with respect to the laminated body of an Example, an ultraviolet-ray was irradiated on the same ultraviolet irradiation conditions as Experiment 1 over one glass, the adhesive layer before hardening was hardened, and it was set as the adhesive layer.

The sample obtained as described above was stored at 85 ° C. and 85% RH for 120 hours. Thereafter, the temperature was returned to room temperature and normal humidity of 23 ° C. and 50% RH, and the presence or absence of whitening was visually confirmed by the following criteria to evaluate moisture and heat whitening resistance, and the haze value of the pressure-sensitive adhesive layer was measured. The haze value was measured according to JIS K7136: 2000 using a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd., product name “NDH2000”) within 30 minutes after returning the sample to room temperature and normal humidity. The results are shown in Table 2.
○: Whitening was not confirmed even when returned to normal temperature and normal humidity. Or partially whitened but disappeared within 30 minutes.
X: Whitened overall. Or after partial whitening, it was not restored even when stored at normal temperature and humidity.

  As can be seen from Table 2, the pressure-sensitive adhesive sheets obtained in the examples were excellent in all of the migration prevention effect, the step following ability, the blister resistance and the wet heat whitening resistance.

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

DESCRIPTION OF SYMBOLS 1 ... Adhesive sheet 10 ... Pre-hardening adhesive layer 12a, 12b ... Release sheet 2 ... Touch panel 3 ... Display body module 4,11 ... Adhesive layer 5a ... 1st film sensor 5b ... 2nd film sensor 51 ... Base material Film 52 ... Electrode 6 ... Cover material 7 ... Printing layer

Claims (8)

It is a pressure-sensitive adhesive sheet for bonding a first display body constituent member having a step on at least a surface to be bonded, and a second display body constituent member,
The first display member constituting member and / or the second display member constituting member at least have a metal electrode mainly composed of a non-oxidized metal, on a surface to be bonded,
The pressure-sensitive adhesive sheet has a pre-curing pressure-sensitive adhesive layer formed by thermally crosslinking the pressure-sensitive adhesive composition,
The adhesive composition is
(Meth) acrylic acid ester polymer (A),
A silane coupling agent (B) having a mercapto group,
An active energy ray-curable component (C),
A pressure-sensitive adhesive sheet characterized in that the (meth) acrylic acid ester polymer (A) contains 10% by mass or more and 35% by mass or less of a hydroxyl group-containing monomer as a monomer unit constituting the polymer. . The pressure-sensitive adhesive sheet according to claim 1, wherein the mercapto group-containing silane coupling agent (B) is a mercapto group-containing oligomer type silane coupling agent. The pressure-sensitive adhesive sheet according to claim 1 or 2, wherein the mercapto group equivalent of the organosilicon compound constituting the silane coupling agent (B) having a mercapto group is 100 g / mol or more and 1000 g / mol or less. . The content of the silane coupling agent (B) having a mercapto group in the adhesive composition is 0.01 parts by mass or more with respect to 100 parts by mass of the (meth) acrylic acid ester polymer (A), It is 5 mass parts or less, The adhesive sheet as described in any one of Claims 1-3 characterized by the above-mentioned. Content of the said active energy ray hardening component (C) in the said adhesive composition is 0.5 mass part or more and 50 mass with respect to 100 mass parts of said (meth) acrylic acid ester polymers (A). The pressure-sensitive adhesive sheet according to any one of claims 1 to 4, wherein the pressure-sensitive adhesive sheet is not more than part. The pressure-sensitive adhesive sheet according to any one of claims 1 to 5 , wherein the pressure-sensitive adhesive composition further contains a crosslinking agent (D). The pressure-sensitive adhesive sheet includes two release sheets,
The pressure-sensitive adhesive sheet according to any one of claims 1 to 6 , wherein the pressure-sensitive adhesive layer before curing is held by the release sheet so as to be in contact with the release surfaces of the two release sheets. A first display member constituting member having a step on at least a surface to be bonded;
A second display body component,
It is a display body provided with the adhesive layer which pastes the said 1st display body structural member and the said 2nd display body structural member mutually,
The first display member constituting member and / or the second display member constituting member at least have a metal electrode mainly composed of a non-oxidized metal on the surface to be bonded,
The said adhesive layer hardens | cures the adhesive layer before hardening of the adhesive sheet as described in any one of Claims 1-7 by irradiation of an active energy ray, The display body characterized by the above-mentioned.