KR20220136059A - Adhesive sheet, repeatedly foldable laminate member and repeatedly foldable device - Google Patents

Abstract

An objective of the present invention is to provide an adhesive sheet which is excellent in bending resistance when being repeatedly folded and can effectively prevent and suppress migration, a repeatedly foldable laminate member, and a repeatedly foldable device According to the present invention, the adhesive sheet (1) comprises an adhesive layer (11) for bonding one foldable member and another foldable member which form the repeatedly foldable device, wherein adhesive forming the adhesive layer (11) contains a rust preventive agent, and the water absorption represented by formula (1), water absorption (%) = {(mass after test - mass before test)/mass before test} × 100, is 0.5% or less when a test is performed, in which the adhesive layer (11) is put in a moist heat environment at 60℃ and 90% RH for 24 hours.

Description

Adhesive sheet, repeated bending laminated member, and repeated bending device

The present invention relates to a pressure-sensitive adhesive sheet for a device subjected to repeated bending, and a repeated bending laminated member and a repeated bending device.

In recent years, as a display body (display) of an electronic device which is a type of device, the flexible display which can bend is proposed. As a flexible display, besides carrying out curved surface shaping|molding only once, as described in patent document 1, the repeated bending|flexion display which is a use made to bend repeatedly (folding) is proposed.

In the above repeated bending display, it is conceivable to bond one bendable member (flexible member) which comprises the said flexible display, and another flexible member together with the adhesive layer of an adhesive sheet. However, when a conventional pressure-sensitive adhesive sheet is used for a repeated bending display, a line is generated in the pressure-sensitive adhesive layer in the portion subjected to repeated bending, and the appearance is deteriorated, and the problem that the visibility as a display decreases, and repeated bending. This causes a problem that floatation or peeling occurs at the interface between the pressure-sensitive adhesive layer and the adherend.

Japanese Patent Laid-Open No. 2016-2764

By the way, in recent years, the enlargement of a touch panel is aimed at, and a mesh-shaped metal electrode, for example, a copper electrode or a silver electrode is examined as such electrode material for touch panels. 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, dendrites are formed due to the precipitation of the positive electrode component, and a short circuit occurs.

This migration is particularly likely to occur when a voltage is applied to the electrode under high temperature and high humidity. When such migration occurs, the resistance value changes and the touch panel does not drive normally. In recent years, in particular, while miniaturization and narrow pitch of the electrode progress, disconnection and short circuit of the electrode due to migration are more likely to occur, and it is desired to sufficiently prevent and suppress migration. In the field of the above-mentioned repetitive bending display, in order to realize a display with high added value that is thinner and lighter, it is strongly desired to miniaturize and narrow the pitch of the electrode.

The present invention has been made in view of the actual situation described above, and it is an object of the present invention to provide an adhesive sheet, a repeatedly bending laminated member, and a repeated bending device that are excellent in bending resistance when repeatedly bent and can effectively prevent and suppress migration do it with

In order to achieve the above object, first, the present invention is an adhesive sheet having a pressure-sensitive adhesive layer for bonding one flexible member constituting a device to be bent repeatedly and another flexible member, wherein the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer is a rust preventive agent A pressure-sensitive adhesive sheet characterized in that the water absorption rate represented by the following formula (1) is 0.5% or less when a test in which the pressure-sensitive adhesive layer is put in a moist heat environment of 60° C. and 90% RH for 24 hours is conducted. Do (Invention 1).

Absorption rate (%) = ｛ (mass after test - mass before test)/mass before test x x 100 . . . (One)

In the pressure-sensitive adhesive sheet of the invention (invention 1), the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer contains a rust preventive agent, and the rust preventive agent segregates in the surface layer of the pressure-sensitive adhesive layer, whereby migration can be effectively prevented and suppressed. Moreover, when the water absorption represented by the said Formula (1) at the time of performing the test which injects|throws-in the adhesive layer in 60 degreeC and the moist heat environment of 90 %RH for 24 hours is 0.5 % or less, the hydrophobicity of an adhesive layer can improve Thereby, migration can be effectively prevented and suppressed. Moreover, when the water absorption represented by said Formula (1) is 0.5 % or less, there exists a tendency to become a soft adhesive layer rich in stress relaxation property. Thereby, the outstanding bending resistance as an adhesive layer for bonding one flexible member which comprises a repeated bending device, and another flexible member can be exhibited.

In the said invention (invention 1), it is preferable that storage elastic modulus G'(-20) in -20 degreeC of the said adhesive is 0.01 MPa or more and 10 MPa or less (invention 2).

In the said invention (invention 1, 2), it is preferable that storage elastic modulus G'(23) in 23 degreeC of the said adhesive is 0.01 MPa or more and 0.5 MPa or less (invention 3).

In the said invention (Inventions 1-3), it is preferable that the storage elastic modulus G' (50) in 50 degreeC of the said adhesive is 0.001 MPa or more and 0.2 MPa or less (Invention 4).

In the said invention (invention 1-4), it is preferable that the gel fraction of the said adhesive is 40 % or more and 100 % or less (invention 5).

In the said invention (invention 1-5), it is preferable that content of the said rust preventive agent in the said adhesive is 0.001 mass % or more and 1 mass % or less (invention 6).

In the said invention (Inventions 1-6), it is preferable that the said rust preventive agent is an azole (Invention 7).

In the said invention (Inventions 1-7), it is preferable that the said adhesive is an acrylic adhesive (Invention 8).

In the said invention (invention 1-8), it is preferable that the said adhesive was obtained from the adhesive composition containing a (meth)acrylic acid ester polymer (A) and a rust preventive agent (B) (invention 9).

In the said invention (invention 9), it is preferable that the glass transition temperature (Tg) of the said (meth)acrylic acid ester polymer (A) is -100 degreeC or more and -45 degrees C or less (invention 10).

In the said invention (inventions 9 and 10), it is preferable that the said (meth)acrylic acid ester polymer (A) contains 0.1 mass % or more and 12 mass % or less of a hydroxyl-containing monomer as a monomer unit which comprises the said polymer. (Invention 11).

In the above inventions (Inventions 1 to 11), it is preferable that two release sheets are provided, and the pressure-sensitive adhesive layer is sandwiched between the two release sheets so as to be in contact with the release surfaces of the two release sheets. do (Invention 12).

Second, the present invention provides a repeatedly bent laminated member comprising one flexible member and another flexible member constituting a device to be repeatedly bent, and a pressure-sensitive adhesive layer for bonding the one flexible member and the other flexible member to each other. of the flexible member and/or the other flexible member has an electrode made of a metal or a metal oxide at least on the surface to be bonded, wherein the pressure-sensitive adhesive layer is composed of a pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet (Inventions 1 to 12) To provide a repeatedly bent laminated member comprising (Invention 13).

Thirdly, the present invention provides a repeating flexion device characterized in that it is provided with the repeating flexion lamination member (invention 13) (invention 14).

The pressure-sensitive adhesive sheet, the repeated bending laminated member and the repeated bending device according to the present invention are excellent in bending resistance when repeatedly bent, and can effectively prevent and suppress migration.

1 is a cross-sectional view of an adhesive sheet according to an embodiment of the present invention.
2 is a cross-sectional view of a repeating flexural laminate member according to an embodiment of the present invention.
3 is a cross-sectional view of a repeat flexing device according to an embodiment of the present invention.
It is explanatory drawing (side view) explaining a dynamic bending test.

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

[adhesive sheet]

The adhesive sheet which concerns on one Embodiment of this invention has an adhesive layer for bonding together one flexible member and another flexible member which comprise the device which bends repeatedly. The pressure-sensitive adhesive layer is composed of a pressure-sensitive adhesive containing a rust inhibitor. In addition, the water absorption rate (hereinafter simply referred to as "water absorption rate" in some cases) represented by the following formula (1) when the pressure-sensitive adhesive layer is subjected to a test in which the pressure-sensitive adhesive layer is charged in a moist heat environment of 60° C. and 90% RH for 24 hours, It is preferable that it is 0.5 % or less. The pressure-sensitive adhesive sheet according to the present embodiment is formed by laminating a release sheet on one or both surfaces of the pressure-sensitive adhesive layer. The repetitive bending device and the flexible member will be described later.

Absorption rate (%) = ｛ (mass after test - mass before test)/mass before test x x 100 . . . (One)

The pressure-sensitive adhesive sheet according to the present embodiment has an adhesive layer for bonding one flexible member constituting a device to be repeatedly bent and another flexible member, and is excellent in bending resistance. Although it is not clear why the said effect arises, it is estimated as follows. When the water absorption rate is 0.5 % or less, the adhesive layer of the adhesive sheet which concerns on this embodiment tends to become a soft adhesive layer rich in stress relaxation property. Thereby, it is estimated that the outstanding bending resistance as an adhesive layer for bonding one flexible member which comprises a repetitive bending device, and another flexible member is exhibited. For example, when it is applied to a repeated bending device and repeatedly bent, it is possible to suppress the occurrence of lines or cloudiness in the pressure-sensitive adhesive layer of the bent portion, and the occurrence of lifting or peeling at the interface between the pressure-sensitive adhesive layer and the flexible member is reduced. can be suppressed

Moreover, in the electrode which concerns on this embodiment, melt|dissolution is prevented and suppressed by the positive electrode, and dendrite formation is prevented and suppressed by the negative electrode. That is, migration in an electrode is effectively prevented and suppressed (this effect may be referred to as a "migration prevention effect"), and a change in the resistance value of an electrode can be suppressed. In addition, since migration is effectively prevented and suppressed, disconnection or short circuit of the electrode is prevented even if one flexible member and/or another flexible member constituting the device that is repeatedly bent has, for example, a miniaturized/narrow-pitched electrode. do. In particular, when the electrode is an electrode of a touch panel, a malfunction in driving of the touch panel due to disconnection or short circuit is prevented.

Although it is not clear why the said effect arises, it is estimated as follows. The adhesive layer of the adhesive sheet which concerns on this embodiment is comprised from the adhesive containing a rust preventive agent. The rust inhibitor tends to segregate easily in the surface layer of the pressure-sensitive adhesive layer. Even when one flexible member and/or another flexible member constituting the device to be repeatedly bent has an electrode, the rust preventive agent tends to stably exist in the vicinity of the electrode, so that the rust preventive agent effectively exerts its action. Thereby, it is estimated that the outstanding migration prevention effect can be exhibited. Moreover, it is thought that a coordination part, such as a diamino group in a rust preventive agent, coordinates with the metal atom of a wiring, forms a chelate compound, and forms a rust preventive film by becoming easy to exist stably in the vicinity of an electrode. Migration becomes easy to occur when water permeates into an electrode, but permeation of water|moisture content is suppressed by formation of a film, and it is estimated that the adhesive sheet which concerns on this embodiment can exhibit the outstanding migration prevention effect. Moreover, when a water absorption is 0.5 % or less, the hydrophobicity of an adhesive layer can be improved, it is in harmony with the action|action of the said rust preventive agent, and it is estimated that the outstanding migration prevention effect can be exhibited.

Here, when the electrode is miniaturized and the pitch is narrowed, the contact area of the pressure-sensitive adhesive layer to the electrode increases because the distance between the gaps between the electrodes is short. When the contact area is large, it is considered that the rust preventive agent is used a lot by forming the rust preventive film by the above-mentioned coordination bonding, and the problem that the density|concentration of the rust preventive agent in the electrode vicinity becomes low arises easily. In particular, in the adhesive between electrodes, since the concentration of the rust preventive agent tends to be low, it is considered that moisture tends to infiltrate and collect, and supply of the rust preventive agent from the adhesive on the electrode upper part to the adhesive between the electrodes tends to be inhibited. Thus, it is estimated that migration will become easy to generate|occur|produce when the density|concentration of the rust preventive agent near an electrode becomes low also partially. In the pressure-sensitive adhesive sheet according to the present embodiment, the pressure-sensitive adhesive layer is composed of a pressure-sensitive adhesive containing a rust preventive agent, and the water absorption is as described above, whereby the above-mentioned problems resulting from the miniaturization and narrow pitch of the electrode can be solved. Specifically, when the water absorption is in the above range, the hydrophobicity of the pressure-sensitive adhesive layer can be improved, and it is possible to suppress the accumulation of moisture in the pressure-sensitive adhesive between electrodes. Thereby, supply of the rust preventive agent from the adhesive on an electrode upper part to the adhesive between electrodes becomes difficult to be inhibited, and the density|concentration of the rust preventive agent in the vicinity of an electrode can be maintained uniformly. As a result, the effect|action of a rust preventive agent becomes easy to be exhibited effectively, and it is estimated that the outstanding migration prevention effect can be exhibited.

It is preferable that the said water absorption in the adhesive sheet which concerns on this embodiment is 0.5 % or less. When the upper limit of a water absorption is 0.5 % or less, the hydrophobicity of an adhesive layer improves, as for the adhesive sheet concerning this embodiment, it harmonizes with the effect by a rust preventive, and becomes the thing excellent in the migration prevention effect. Moreover, it tends to become a soft adhesive layer rich in stress relaxation property, and it is easy to have bending resistance suitable as an adhesive layer for bonding one flexible member and another flexible member which comprise a repetitive bending device. From the viewpoint of the migration prevention effect and bending resistance, the upper limit of the water absorption is more preferably 0.3% or less, particularly preferably 0.2% or less, further preferably 0.1% or less, and most preferably less than 0.1%. Moreover, the lower limit of the said water absorption is although it does not specifically limit, Usually, it is 0 % or more, It is more preferable that it is 0.001 % or more, It is especially preferable that it is 0.01 % or more.

The storage elastic modulus G'(-20) at -20°C of the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer is preferably 10 MPa or less, more preferably 5 MPa or less, particularly preferably 1 MPa or less, and further 0.3 MPa or less. It is preferable that it is less than or equal, and it is most preferable that it is 0.12 MPa or less. When the upper limit of storage elastic modulus G'(-20) in -20 degreeC exists in the said range, while the adhesive layer obtained becomes easy to express desired adhesiveness, the force which acts on a flexible member from an adhesive layer with bending|flexion It becomes a thing which is easy to reduce or disperse|distribute this, and becomes a thing excellent in bending resistance. In particular, when one flexible member and/or another flexible member has an electrode, it is estimated that the stress by which an adhesive layer deform|transforms with bending|flexion is applied in the electrode vicinity. Among them, when the electrode is miniaturized and narrow-pitched, there are countless places where stress is applied. Therefore, when viewed as a whole of the device, the stress applied to the electrode increases significantly with bending. That is, when the flexible member has an electrode, it is important to reduce or disperse the stress applied to the electrode with bending, so that the upper limit of the storage elastic modulus G'(-20) at -20°C is in the above range. , The pressure-sensitive adhesive layer obtained is easy to reduce or disperse the stress applied to the electrode from the pressure-sensitive adhesive layer with bending. Thereby, the adhesive sheet which concerns on this embodiment becomes a thing more excellent in bending resistance. In addition, from the viewpoint of cohesive force, the storage elastic modulus G'(-20) at -20°C of the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer is preferably 0.01 MPa or more, preferably 0.05 MPa or more, and particularly preferably 0.08 MPa or more. and, more preferably, 0.1 MPa or more. Thereby, it becomes easy to express desired adhesiveness.

The storage elastic modulus G' (23) at 23 ° C. of the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer is preferably 0.5 MPa or less, more preferably 0.2 MPa or less, particularly preferably 0.1 MPa or less, and further, 0.08 MPa or less. Preferably, it is most preferably 0.04 or less. When the upper limit of the storage elastic modulus G'(23) in 23 degreeC exists in the said range, the pressure-sensitive adhesive layer obtained is easy to reduce or disperse|distribute the stress which acts on a flexible member from an adhesive layer with bending|flexion. In particular, even when the flexible member has a miniaturized/narrow-pitched electrode, it is easy to reduce or disperse the stress applied to the electrode from the pressure-sensitive adhesive layer due to bending. Thereby, while becoming easy to exhibit desired adhesiveness, the adhesive layer obtained becomes more excellent in bending resistance. On the other hand, it is preferable that storage elastic modulus G'(23) in 23 degreeC is 0.01 MPa or more, It is especially preferable that it is 0.02 MPa or more, Furthermore, it is preferable that it is 0.03 MPa or more. Thereby, workability, such as a cutting process, becomes favorable.

The storage elastic modulus G' (50) at 50 ° C. of the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer is preferably 0.2 MPa or less, more preferably 0.1 MPa or less, particularly preferably 0.06 MPa or less, and further, 0.03 MPa or less. It is preferable, and it is most preferable that it is 0.02 MPa or less. When the upper limit of the storage elastic modulus G' (50) in 50 degreeC exists in the said range, the adhesive layer obtained becomes a thing easy to reduce or disperse|distribute the stress which acts on a flexible member from an adhesive layer with bending|flexion. In particular, even when the flexible member has a miniaturized/narrow-pitched electrode, it is easy to reduce or disperse the stress applied to the electrode from the pressure-sensitive adhesive layer due to bending. Thereby, the device excellent in bending resistance especially at high temperature can be obtained. On the other hand, the storage modulus G' (50) at 50°C is preferably 0.001 MPa or more, more preferably 0.005 MPa or more, particularly preferably 0.008 MPa or more, and further preferably 0.01 MPa or more, and 0.015 MPa or more. it is most preferable Accordingly, even at a high temperature, the pressure-sensitive adhesive layer does not become too flexible and the cohesive force is maintained.

The gel fraction of the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer is preferably 40% or more, more preferably 45% or more, particularly preferably 50% or more, further preferably 55% or more, and most preferably 57% or more. do. When the lower limit of the said gel fraction exists in the said range, the adhesive layer obtained exhibits suitable cohesive force, and it becomes easy to satisfy the value of the storage elastic modulus mentioned above. In addition, as the crosslinking density of the pressure-sensitive adhesive layer increases, it tends to become difficult to pass moisture, and the above-mentioned water absorption rate is easily satisfied. Thereby, the adhesive sheet of this embodiment becomes a thing more excellent in bending resistance, and can withstand repeated bending. On the other hand, the gel fraction of the pressure-sensitive adhesive in the present embodiment is preferably 100% or less, more preferably 85% or less, particularly preferably 70% or less, further preferably 65% or less, and 59% or less Most preferred. Thereby, it is estimated that the destruction of the crosslinked structure in the adhesive by repeated bending is suppressed. Moreover, when the upper limit of the said gel fraction exists in the said range, the obtained adhesive layer exhibits suitable cohesive force, and it becomes easy to reduce or disperse|distribute the stress which acts on a flexible member from an adhesive layer with bending. In particular, even when the flexible member has a miniaturized/narrow-pitched electrode, it is easy to reduce or disperse the stress applied to the electrode from the pressure-sensitive adhesive layer due to bending. Therefore, the adhesive sheet of this embodiment becomes a thing more excellent in bending resistance, and can withstand repeated bending. In addition, the measuring method of the gel fraction in this specification is as showing in the test example mentioned later.

A specific configuration as an example of the pressure-sensitive adhesive sheet according to the present embodiment is shown in FIG. 1 .

As shown in FIG. 1 , the pressure-sensitive adhesive sheet 1 according to the embodiment includes two release sheets 12a and 12b and the two release sheets 12a and 12b described above so as to be in contact with the release surfaces of the two release sheets 12a and 12b. It is comprised by the adhesive layer 11 clamped by each release sheet 12a, 12b. In addition, the peeling surface of the peeling sheet in this specification means the surface which has peelability in a peeling sheet, and it includes both the surface to which the peeling process was performed, and the surface which shows peelability even if it does not perform a peeling process.

1. Components

1-1. adhesive layer

The adhesive layer 11 of the adhesive sheet 1 which concerns on this embodiment is comprised with the adhesive containing a rust preventive agent. The type of the pressure-sensitive adhesive is not particularly limited as long as the above physical properties (particularly water absorption) are satisfied, for example, any of an acrylic pressure-sensitive adhesive, a polyester-based pressure-sensitive adhesive, a polyurethane-based pressure-sensitive adhesive, a rubber-based pressure-sensitive adhesive, a silicone pressure-sensitive adhesive, and the like. In addition, any of an emulsion type, a solvent type, or a non-solvent type may be sufficient as the said adhesive, and any of a crosslinked type or a non-crosslinked type may be sufficient as it. Among them, an acrylic pressure-sensitive adhesive that easily satisfies the physical properties described above and is excellent also in adhesive physical properties and optical properties is preferable, and particularly, a solvent-type acrylic pressure-sensitive adhesive is preferable.

Specifically, the pressure-sensitive adhesive in the present embodiment is preferably obtained from a (meth)acrylic acid ester polymer (A) and an adhesive composition containing a rust preventive agent (B) (hereinafter sometimes referred to as “adhesive composition P”). and especially, it is preferable that it is an adhesive formed by bridge|crosslinking the adhesive composition containing a (meth)acrylic acid ester polymer (A), a rust preventive agent (B), and a crosslinking agent (C). It is preferable that the said adhesive composition further contains a silane compound (D). If it is such an adhesive, it is easy to satisfy|fill the physical properties mentioned above, and favorable adhesive force is easy to be obtained. In addition, in this specification, (meth)acrylic acid means both acrylic acid and methacrylic acid. The same is true for other similar terms. In addition, the concept of "copolymer" shall also be included in "polymer".

(1) Components of the adhesive composition P

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

It is preferable that the (meth)acrylic acid ester polymer (A) contains the reactive functional group containing monomer which has a reactive functional group in a molecule|numerator as a monomer which comprises the said polymer. By containing this reactive functional group-containing monomer, it reacts with a crosslinking agent (C) to be described later via a reactive functional group derived from the reactive functional group-containing monomer, thereby forming a crosslinked structure (three-dimensional network structure), and a predetermined A pressure-sensitive adhesive having cohesive force is obtained.

The (meth)acrylic acid ester polymer (A) contains a reactive functional group-containing monomer as a monomer unit constituting the polymer, a monomer having a hydroxyl group in the molecule (hydroxyl group-containing monomer), a monomer having a carboxyl group in the molecule (carboxyl group-containing monomer) , a monomer having an amino group in the molecule (amino group-containing monomer), etc. are preferably mentioned. These reactive functional group containing monomers may be used individually by 1 type, and may use 2 or more types together.

Among the reactive functional group-containing monomers, a hydroxyl group-containing monomer having excellent reactivity with the crosslinking agent (C) and having little adverse effect on the electrode is particularly preferable.

As the hydroxyl group-containing monomer, for example, (meth)acrylic acid 2-hydroxyethyl, (meth)acrylic acid 2-hydroxypropyl, (meth)acrylic acid 3-hydroxypropyl, (meth)acrylic acid 2-hydroxybutyl, ( (meth)acrylic acid hydroxyalkyl esters, such as meth)acrylic-acid 3-hydroxybutyl and (meth)acrylic-acid 4-hydroxybutyl, etc. are mentioned. Among them, from the viewpoint of reactivity with the crosslinking agent (C), (meth)acrylic acid 2-hydroxyethyl and (meth)acrylic acid 4-hydroxybutyl are preferable, and 2-hydroxyethyl acrylate and 4-hydroxybutyl acrylate are preferred. more preferably. These may be used independently and may be used in combination of 2 or more type.

The (meth)acrylic acid ester polymer (A) preferably contains 0.1 mass% or more of a reactive functional group-containing monomer (especially a hydroxyl group-containing monomer) as a monomer unit constituting the polymer, more preferably 0.3 mass% or more It is preferable, and it is preferable to contain especially 0.6 mass % or more, Furthermore, it is preferable to contain 0.9 mass % or more. Thereby, the balance of the adhesive force of the adhesive obtained and cohesive force is achieved favorably. Moreover, there exists a tendency for a rust preventive agent (B) to become easy to segregate in the surface layer of an adhesive layer. In particular, when the reactive functional group-containing monomer is a hydroxyl group-containing monomer, when the (meth)acrylic acid ester polymer (A) contains the hydroxyl group-containing monomer in the above amount as a monomer unit, the above-described storage elastic modulus or gel fraction, adhesive force described later, etc. It becomes easy to satisfy the physical property value of , and the adhesive obtained becomes a thing excellent in bending resistance. Moreover, a rust preventive agent (B) becomes easy to segregate suitably on the adhesive surface, and becomes the thing excellent in the migration prevention effect.

Further, the (meth)acrylic acid ester polymer (A) preferably contains 12% by mass or less of a reactive functional group-containing monomer (especially a hydroxyl group-containing monomer) as a monomer unit constituting the polymer, and 8% by mass or less. It is preferable, and it is preferable to contain especially 4 mass % or less, Furthermore, it is preferable to contain 2 mass % or less, It is most preferable to contain 1.5 mass % or less. Thereby, while there exists a tendency for water absorption to become easy to satisfy|fill the above-mentioned value, it becomes easy to satisfy|fill physical property values, such as the storage elastic modulus mentioned above, a gel fraction, and adhesive force mentioned later. In particular, when the reactive functional group-containing monomer is a hydroxyl group-containing monomer, when the (meth)acrylic acid ester polymer (A) contains the hydroxyl group-containing monomer in the above amount as a monomer unit, the water absorption will more easily fall within the above range. Thereby, the hydrophobicity of an adhesive layer can be improved and the migration prevention effect becomes more excellent. Moreover, it is easy to satisfy the above-mentioned storage elastic modulus and gel fraction, and while the adhesive layer obtained becomes a soft thing rich in stress relaxation property, it is easy to satisfy the adhesive force mentioned later, and it is excellent also in adhesiveness with a to-be-adhered body, and these together combine to have bending resistance. It will be better than this.

It is preferable that the (meth)acrylic acid ester polymer (A) does not contain a carboxyl group containing monomer as a monomeric unit which comprises the said polymer. Since the carboxyl group is an acid component, there is a concern that a change in resistance value due to corrosion of the electrode in contact with the pressure-sensitive adhesive occurs, but by not containing a carboxyl group-containing monomer, corrosion of the electrode can be prevented and the resistance value change can be effectively prevented and suppressed. However, said "does not contain a carboxyl group-containing monomer" means to allow containing a carboxyl group-containing monomer to such an extent that the electrode which the adhesive obtained is contacted is not adversely affected. Specifically, in the (meth)acrylic acid ester polymer (A), as a monomer unit, a carboxyl group-containing monomer is contained in an amount of 0.1 mass% or less, preferably 0.01 mass% or less, more preferably 0.001 mass% or less. allowed

Moreover, it is preferable that (meth)acrylic acid ester polymer (A) contains (meth)acrylic acid alkylester as a monomer unit which comprises the said polymer. Thereby, favorable adhesiveness can be expressed.

In particular, the (meth)acrylic acid ester polymer (A) has a glass transition temperature (Tg) of 0° C. or less as a homopolymer other than the reactive functional group-containing monomer described above as a monomer unit constituting the polymer, and the carbon number of the alkyl group is 2 It is preferable to contain the (meth)acrylic acid alkylester of -20, and the monomer whose glass transition temperature (Tg) as a homopolymer exceeds 0 degreeC.

The (meth)acrylic acid ester polymer (A) is a monomer unit constituting the polymer, and has a glass transition temperature (Tg) of 0° C. or less as a homopolymer, and an alkyl group (meth) acrylic acid alkyl ester having 2 to 20 carbon atoms ( Hereinafter, it becomes easy to set the glass transition temperature (Tg) of a (meth)acrylic acid ester polymer (A) to the range mentioned later by containing "low Tg alkyl acrylate"). Thereby, it becomes easy to satisfy|fill the above-mentioned physical property (water absorption rate, storage elastic modulus), Furthermore, while it is more excellent in bending resistance, it becomes a thing excellent in the migration prevention effect. Moreover, the adhesive obtained can express preferable adhesiveness. From such a viewpoint, the (meth)acrylic acid ester polymer (A) preferably contains 80 mass% or more of low Tg alkyl acrylate as a monomer unit constituting the polymer, and more preferably contains 85 mass% or more. And it is preferable to contain especially 90 mass % or more, Furthermore, it is preferable to contain 94 mass % or more. Moreover, as for the (meth)acrylic acid ester polymer (A), it is preferable to contain 99.9 mass % or less as an upper limit of the said low Tg alkyl acrylate as a monomer unit which comprises the said polymer, It is especially preferable to contain 99 mass % or less. And it is preferable to contain 97 mass % or less further. If the upper limit of content of the said low Tg alkyl acrylate is the above, another monomer component can be introduce|transduced in a suitable quantity in (meth)acrylic acid ester polymer (A).

Examples of the low-Tg alkyl acrylate include ethyl acrylate (Tg-20°C), n-butyl acrylate (Tg-55°C), isobutyl acrylate (Tg-26°C), and n-octyl acrylate (Tg-65°C). ), isooctyl acrylate (Tg-58°C), 2-ethylhexyl acrylate (Tg-70°C), 2-ethylhexyl methacrylate (Tg-10°C), isononyl acrylate (Tg-58°C), acrylic acid Isodecyl (Tg-60℃), isodecyl methacrylate (Tg-41℃), acrylic acid n-lauryl (Tg-23℃), methacrylic acid n-lauryl (Tg-65℃), tridecyl acrylate (Tg-55 degreeC), tridecyl methacrylate (-40 degreeC), isostearyl acrylate (Tg-18 degreeC), etc. are mentioned preferably. Among them, as a low Tg alkyl acrylate, it is more preferable that the Tg of the homopolymer is -40°C or less, and particularly preferably -50°C or less, from the viewpoint of imparting adhesiveness more effectively. Specifically, from a viewpoint of suppressing migration, n-butyl acrylate and 2-ethylhexyl acrylate are especially preferable, and it is also preferable to use these together. These may be used independently and may be used in combination of 2 or more type. In addition, the alkyl group in C2-C20 (meth)acrylic-acid alkylester of an alkyl group means a linear, branched or cyclic alkyl group.

In addition, from the viewpoint of suppressing migration by improving the hydrophobicity of the obtained pressure-sensitive adhesive layer, the low-Tg alkyl acrylate is preferably a (meth)acrylic acid alkylester having 5 or more carbon atoms in the alkyl group, at least in part, the alkyl group It is more preferable that it is (meth)acrylic-acid alkylester whose carbon number is 7 or more. Specifically, 2-ethylhexyl acrylate is particularly preferable. In addition, from the viewpoint of improving bending resistance while suppressing migration, the ratio of (meth)acrylic acid alkyl ester having 5 or more (preferably 7 or more) carbon atoms of the alkyl group in the entire low Tg alkyl acrylate is 40 mass It is preferable that they are % or more and 85 mass % or less, It is more preferable that they are 50 mass % or more and 75 mass % or less, It is especially preferable that they are 60 mass % or more and 65 mass % or less.

In addition, the (meth)acrylic acid ester polymer (A) is a monomer unit constituting the polymer, and a homopolymer having a glass transition temperature (Tg) exceeding 0°C (hereinafter referred to as a “hard monomer” in some cases) By containing it, it becomes easy for the adhesive obtained to have moderate cohesive force and adhesiveness. Thereby, even if it bends repeatedly, it becomes easy to suppress that a line|wire or cloudiness arises in a bent part, and the adhesive layer obtained is easy to suppress generation|occurrence|production of problems, such as a float and peeling. From such a viewpoint, the glass transition temperature (Tg) of the hard monomer is more preferably 60°C or higher, particularly preferably 90°C or higher, and still more preferably 120°C or higher. In addition, in consideration of compatibility and copolymerizability with other monomers constituting the (meth)acrylic acid ester polymer (A), the glass transition temperature (Tg) of the hard monomer is preferably 250° C. or less, and 200° C. or less. It is more preferable, and it is especially preferable that it is 150 degrees C or less.

In the (meth)acrylic acid ester polymer (A), from the viewpoint of imparting a cohesive force and tackiness suitable for the obtained pressure-sensitive adhesive, the hard monomer is preferably contained in an amount of 1% by mass or more as a monomer constituting the polymer, 2 It is more preferable that it is contained in mass % or more, and it is especially preferable that it is contained 4 mass % or more. In addition, it is preferable that the said hard monomer contains 8 mass % or less as a monomer which comprises a polymer from a viewpoint of making it excellent in compatibility with the (meth)acrylic acid ester polymer (A) obtained and another component, 7 It is more preferable to be contained by mass % or less, and it is especially preferable to contain 6 mass % or less. When a hard monomer exists in the said range, it becomes easy to set the glass transition temperature (Tg) of a (meth)acrylic acid ester polymer (A) to the range mentioned later. Thereby, it becomes easy to satisfy|fill the above-mentioned physical property (water absorption rate, storage elastic modulus), Furthermore, while it is more excellent in bending resistance, it becomes a thing excellent in the migration prevention effect.

Examples of the hard monomer include methyl acrylate (Tg10°C), methyl methacrylate (Tg105°C), ethyl methacrylate (Tg65°C), n-butyl methacrylate (Tg20°C), isobutyl methacrylate (Tg48°C), t-butyl methacrylate (Tg107°C), n-stearyl acrylate (Tg30°C), n-stearyl methacrylate (Tg38°C), cyclohexyl acrylate (Tg15°C), cyclomethacrylate Hexyl (Tg66°C), phenoxyethyl acrylate (Tg5°C), phenoxyethyl methacrylate (Tg54°C), benzyl methacrylate (Tg54°C), isobornyl acrylate (Tg94°C), isobornyl methacrylate (Tg180°C), acryloylmorpholine (Tg145°C), adamantyl acrylate (Tg115°C), adamantyl methacrylate (Tg141°C), dimethyl acrylamide (Tg89°C), acrylamide (Tg165°C), etc. An acryl-type monomer, vinyl acetate (Tg32 degreeC), styrene (Tg80 degreeC), etc. are mentioned preferably, From a compatible viewpoint, an acryl-type monomer is more preferable. These may be used independently and may be used in combination of 2 or more type.

Among the hard monomers, the group consisting of methyl methacrylate, isobornyl acrylate and acryloylmorpholine from the viewpoint of further exhibiting the performance of the hard monomer while preventing adverse effects on other properties such as compatibility with other components. It is preferable to contain at least one selected from In particular, it is preferable to use acryloylmorpholine.

Here, the glass transition temperature (Tg) of the (meth)acrylic acid ester polymer (A) is preferably -45°C or lower, more preferably -50°C or lower, particularly preferably -55°C or lower, and further - It is preferable that it is 58 degrees C or less. The glass transition temperature (Tg) is preferably -100°C or higher, more preferably -85°C or higher, particularly preferably -75°C or higher, and further preferably -65°C or higher. When the glass transition temperature (Tg) of the (meth)acrylic acid ester polymer (A) is in the above range, the water absorption and storage elastic modulus easily fall within the above ranges, and the flex resistance is more excellent and the migration prevention effect is more excellent. . In addition, the glass transition temperature (Tg) of the (meth)acrylic acid ester polymer (A) shall be computed by FOX formula based on the glass transition temperature (Tg) as a homopolymer of each monomer.

The (meth)acrylic acid ester polymer (A) may contain other monomers as a monomer unit constituting the polymer as desired. As another monomer, even in order not to interfere with the action of a reactive functional group containing monomer, the monomer which does not contain the functional group which has reactivity is preferable. As such another monomer, (meth)acrylic-acid alkoxy alkylesters, such as (meth)acrylic-acid methoxyethyl and (meth)acrylic-acid ethoxyethyl, etc. are mentioned, for example. These may be used independently and may be used in combination of 2 or more type.

It is preferable that the (meth)acrylic acid ester polymer (A) is a solution polymer obtained by the solution polymerization method. By being a solution polymer, a high molecular weight polymer is easy to be obtained, and the adhesive excellent in durability is obtained.

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

The lower limit of the weight average molecular weight of the (meth)acrylic acid ester polymer (A) is preferably 200,000 or more, more preferably 400,000 or more, particularly preferably 550,000 or more, and further preferably 650,000 or more. While the adhesive obtained as the lower limit of the weight average molecular weight of a (meth)acrylic acid ester polymer (A) is the above, while becoming a thing excellent in durability, it becomes easy to segregate a rust preventive agent (B) in the adhesive layer surface layer. 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 of the weight average molecular weight of the (meth)acrylic acid ester polymer (A) is preferably 2 million or less, more preferably 1.5 million or less, particularly preferably 1 million or less, and further preferably 750,000 or less. . If the upper limit of the weight average molecular weight of the (meth)acrylic acid ester polymer (A) is the above, it will be easy to satisfy the above-mentioned physical properties (water absorption, storage elastic modulus, and gel fraction). Moreover, the adhesive obtained will exhibit suitable adhesiveness.

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

(1-2) Rust inhibitor (B)

As a rust preventive agent (B) in this embodiment, it is preferable to segregate suitably in the surface layer of an adhesive layer. Since such a rust preventive agent (B) becomes easy to exist stably in the surface layer of an adhesive layer, the effect|action can be exhibited effectively and it can contribute to a migration prevention effect. Examples of the rust inhibitor (B) include azoles such as azole compounds, triazole compounds, benzotriazole compounds, thiazole compounds, benzothiazole compounds, imidazole compounds, and benzoimidazole compounds, and phosphorus compounds. compound, a nitrite-type compound, etc. are mentioned. Among these, it is easy to segregate suitably for the surface layer of an adhesive layer, and a viewpoint to the more excellent migration prevention effect to azoles is preferable, and especially a benzotriazole type compound is preferable. A rust preventive agent (B) may be used individually by 1 type, and may use 2 or more types together.

Examples of the benzotriazole-based compound include 1H-benzotriazole, 1H-tolytriazole, 1-[N,N-bis(2-ethylhexyl)aminomethyl]benzotriazole, 1-[N,N -bis(2-ethylhexyl)aminomethyl]methylbenzotriazole, carboxybenzotriazole, 2,2'-[[(methyl-1H-benzotriazol-1-yl)methyl]imino]bisethanol, etc. can be heard Among them, 1H-benzotriazole, 1H-tolytriazole, 1-[N,N-bis(2-ethylhexyl)aminomethyl]benzotriazole and 1-[N,N-bis(2-ethylhexyl) ) aminomethyl]methylbenzotriazole is preferable, and 1-[N,N-bis(2-ethylhexyl)aminomethyl]methylbenzotriazole is particularly preferable. Thereby, generation|occurrence|production of a migration can be suppressed more effectively.

It is preferable that content of the rust preventive agent (B) in the adhesive composition P is 0.001 mass part or more with respect to 100 mass parts of (meth)acrylic acid ester polymer (A), It is more preferable that it is 0.01 mass part or more, It is especially 0.02 mass part. It is preferable that it is more than it, Furthermore, it is preferable that it is 0.04 mass part or more, and it is most preferable that it is 0.045 mass part or more. Thereby, it becomes easy to segregate moderately in the surface layer of the adhesive layer from which a rust preventive agent (B) is obtained, and it becomes a thing excellent in the migration prevention effect.

Moreover, it is preferable that content of the rust preventive agent (B) in adhesive composition P is 1 mass part or less with respect to 100 mass parts of (meth)acrylic acid ester polymer (A), It is more preferable that it is 0.8 mass part or less, Especially 0.5 It is preferable that it is a mass part or less, Furthermore, it is preferable that it is 0.3 mass part or less. Thereby, since the adhesive layer obtained can suppress the absolute amount of the rust preventive agent (B) contained in an adhesive layer, the color change of wiring resulting from a rust preventive agent (B) can be suppressed. In addition, when the upper limit of the content of the rust preventive agent (B) is within the above range, the content of the adhesive component (for example, the (meth)acrylic acid ester polymer (A) described above) contained in the pressure-sensitive adhesive layer can be relatively increased. Therefore, the adhesive layer obtained can exhibit favorable adhesiveness, exhibiting a migration prevention effect.

It is preferable that content of the rust preventive (B) in an adhesive is 0.001 mass % or more, It is more preferable that it is 0.01 mass % or more, It is especially preferable that it is 0.02 mass % or more, Furthermore, it is preferable that it is 0.04 mass % or more, It is 0.045 mass % or more is most preferable. Thereby, it becomes easy to segregate suitably in the surface layer of the adhesive layer obtained, and a rust preventive agent (B) becomes a thing more excellent in the migration prevention effect.

Moreover, it is preferable that content of the rust preventive (B) in an adhesive is 1 mass % or less, It is more preferable that it is 0.8 mass % or less, It is especially preferable that it is 0.5 mass % or less, Furthermore, it is preferable that it is 0.3 mass % or less. Thereby, since the adhesive layer obtained from a rust preventive agent (B) can suppress the absolute amount of the rust preventive agent (B) contained in an adhesive layer, the color change of the wiring resulting from a rust preventive agent (B) can be suppressed. In addition, when the upper limit of the content of the rust preventive agent (B) is within the above range, the content of the adhesive component (for example, the (meth)acrylic acid ester polymer (A) described above) contained in the pressure-sensitive adhesive layer can be relatively increased. Therefore, the adhesive layer obtained can exhibit favorable adhesiveness, exhibiting a migration prevention effect.

(1-3) Crosslinking agent (C)

The crosslinking agent (C) crosslinks the (meth)acrylic acid ester polymer (A) by heating or the like of the adhesive composition P containing the crosslinking agent (C) to form a three-dimensional network structure. Thereby, the cohesive force of the adhesive obtained improves, and a storage elastic modulus and a gel fraction become easy to fall into the above-mentioned range.

As said crosslinking agent (C), what is necessary is just to react with the reactive functional group which the (meth)acrylic acid ester polymer (A) has, For example, an isocyanate type crosslinking agent, an epoxy type crosslinking agent, an amine type crosslinking agent, a melamine type crosslinking agent, an aziridine type crosslinking agent, and a hydrazine-based crosslinking agent, an aldehyde-based crosslinking agent, an oxazoline-based crosslinking agent, a metal alkoxide-based crosslinking agent, a metal chelate-based crosslinking agent, a metal salt-based crosslinking agent, and an ammonium salt-based crosslinking agent. 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. Moreover, a crosslinking agent (C) can be used individually by 1 type or in combination of 2 or more type.

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

It is preferable that content of the crosslinking agent (C) in the adhesive composition P is 0.01 mass part or more with respect to 100 mass parts of (meth)acrylic acid ester polymer (A), It is more preferable that it is 0.05 mass part or more, It is especially 0.1 mass part It is preferable that it is more than it, Furthermore, it is preferable that it is 0.2 mass part or more, and it is most preferable that it is 0.25 mass part or more. Moreover, it is preferable that the said content is 5 mass parts or less, It is more preferable that it is 1 mass part or less, It is especially preferable that it is 0.8 mass parts or less, Furthermore, it is preferable that it is 0.6 mass parts or less. When content of a crosslinking agent (C) exists in said range, a storage elastic modulus and a gel fraction will fall easily into the above-mentioned range.

(1-4) Silane compound (D)

It is preferable that the adhesive composition P of this embodiment contains a silane compound (D). By containing the silane compound (D), the migration prevention effect becomes more excellent.

The silane compound (D) is preferably an organosilicon compound having at least one alkoxysilyl group. Thereby, in the adhesive layer obtained, adhesiveness with the flexible member which is a to-be-adhered body improves, and adhesive force becomes a more preferable thing. Moreover, it is thought that water infiltration into the electrode adjacent to the adhesive layer obtained is suppressed by the effect|action of an alkoxysilyl group, and, by this, becomes a thing excellent in the migration prevention effect.

The organosilicon compound having at least one alkoxysilyl group as the silane compound (D) may be, for example, a silane coupling agent, and specific examples thereof include vinyltrimethoxysilane, vinyltriethoxysilane, and methacryloxypropyltrimethoxysilane. Polymerizable unsaturated group containing silicon compounds, such as; silicon compounds having an epoxy structure such as 3-glycidoxypropyltrimethoxysilane and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; mercapto group-containing silicon compounds such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, and 3-mercaptopropyldimethoxymethylsilane; Amino group-containing silicon compounds such as 3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, and N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane ; 3-chloropropyltrimethoxysilane, 3-isocyanatepropyltriethoxysilane, or at least one of these, and methyltriethoxysilane, ethyltriethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, etc. condensate with an alkyl group-containing silicon compound; and the like. These may be used individually by 1 type, and may be used in combination of 2 or more type. Especially, the silicon compound which has an epoxy structure from a viewpoint of a migration prevention effect, and an adhesive viewpoint is preferable, and 3-glycidyloxypropyl trimethoxysilane is especially preferable.

Moreover, as for a silane compound (D), the organosilicon compound which has an alkoxysilyl group at both terminals is preferable. Preferably, it is a compound represented by the following general formula (I).

[Tue 1]

(R ¹ in the formula is a divalent hydrocarbon group which may have a nitrogen atom. R ² to R ⁷ in the formula are each independently an alkyl group.)

It is preferable that carbon number of the divalent hydrocarbon group of said R< ¹ > is 1-10 from a viewpoint of a migration prevention effect, It is especially preferable that it is 3-8, Furthermore, it is preferable that it is 5-7. Moreover, it is preferable that the said hydrocarbon group is a saturated hydrocarbon group, and it is especially preferable that it is a chain type saturated hydrocarbon group. Moreover, it is preferable that the said hydrocarbon group contains an alkylene group, and it is especially preferable that it is an alkylene group. It is preferable that carbon number of this alkylene group is 1-10, It is especially preferable that it is 3-8, Furthermore, it is preferable that it is 5-7.

When R ¹ has a nitrogen atom, the nitrogen atom may be present in the side chain of the hydrocarbon group, but is preferably present in the main chain of the hydrocarbon group. When said R< ¹ > has a nitrogen atom, it is preferable that it is 1-5, and, as for the number of nitrogen atoms contained in R< ¹ >, it is especially preferable that it is 2-3. The nitrogen atom is preferably an amino group or an amide group, particularly preferably an amino group, and more preferably present in the main chain of the hydrocarbon group as a secondary amine or a tertiary amine.

When R ¹ has a nitrogen atom, R ¹ preferably includes a skeleton of -(CH) _m -NH-, and includes a skeleton of -(CH) _m -NH-(CH) _n - More preferably, in particular, it is preferable to include a skeleton of -(CH) _m -NH-(CH) _n -NH-, furthermore, -(CH) _m -NH-(CH) _n -NH-(CH ) It is preferable to include a skeleton of _p -. Said m, n, and p are positive integers, It is preferable that it is 1-5, It is especially preferable that it is 2-4.

It is preferable that said R< ¹ > does not have a sulfur atom in a principal chain. When the main chain has a sulfur atom, metal sulfide is likely to be formed starting from the interface between the pressure-sensitive adhesive and the electrode made of metal (especially silver) or metal oxide (especially ITO) in a durability test environment. Thereby, there exists a possibility that the above-mentioned migration prevention effect may be impaired.

It is preferable that carbon number of the alkyl group of said R< ² >-R< ⁷ > is 1-6, respectively, It is especially preferable that it is 1-4, Furthermore, it is preferable that it is 1-2. Moreover, it is preferable that all of said R< ² >-R< ⁷ > are the same alkyl groups, and it is most preferable that all are methyl groups.

As a lower limit, it is preferable that content of the silane compound (D) in the 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), It is more preferable that it is 0.1 mass part or more, Especially, It is preferable that it is 0.16 mass part or more, and it is more preferable that it is 0.22 mass part or more. Moreover, as for the said content, as an upper limit, it is preferable that it is 2 mass parts or less, It is more preferable that it is 1 mass part or less, It is especially preferable that it is 0.6 mass part or less, It is further more preferable that it is 0.3 mass parts or less. When content of a silane compound (D) is said range, the effect|action by a silane compound (D) is exhibited effectively, and the migration prevention effect becomes more excellent.

(1-5) Various additives

To the pressure-sensitive adhesive composition P, if desired, various additives commonly used in acrylic pressure-sensitive adhesives, for example, ultraviolet absorbers, antistatic agents, tackifiers, antioxidants, light stabilizers, softeners, fillers, refractive index modifiers, etc. can be added. . In addition, the polymerization solvent and dilution solvent mentioned later shall not be contained in the additive which comprises the adhesive composition P.

As the ultraviolet absorber (E), for example, a compound such as a benzophenone-based, benzotriazole-based, benzoate-based, benzooxazinone-based, triazine-based, phenyl salicylate-based, cyanoacrylate-based, nickel complex salt-based Among these, it is preferable to use at least 1 sort(s) of a benzophenone type compound, a benzotriazole type compound, and a triazine type compound.

Examples of the benzophenone-based compound include 2,2-dihydroxy-4-methoxybenzophenone, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy- 4-methoxybenzophenone-5-sulfonic acid hydrate, 2-hydroxy-4-n-octyloxybenzophenone, etc. are mentioned, Among these, 2, 2- dihydroxy-4-methoxybenzophenone is It is preferable to use

Examples of the benzotriazole compound include 2-(2-hydroxy-5-t-butylphenyl)-2H-benzotriazole, octyl-3-[3-t-butyl-4-hydroxy-5-(5) -Chloro-2H-benzotriazol-2-yl)phenyl]propionate, 2-ethylhexyl-3-[3-t-butyl-4-hydroxy-5-(5-chloro-2H-benzotriazole) -2-yl)phenyl]propionate, 3-(2H-benzotriazol-2-yl)-5-(1,1-dimethylethyl)-4-hydroxy-benzenepropanoic acid, and the like; Among these, it is preferable to use 3-(2H-benzotriazol-2-yl)-5-(1,1-dimethylethyl)-4-hydroxy-benzenepropanoic acid.

Examples of the triazine-based compound include 2,4-bis[2-hydroxy-4-butoxyphenyl]-6-(2,4-dibutoxyphenyl)-1,3,5-triazine, 2-[4 and 6-di(2,4-xylyl)-1,3,5-triazin-2-yl]-5-octyloxyphenol.

The above ultraviolet absorbers (E) may be used individually by 1 type, and may be used in combination of 2 or more type.

When the adhesive composition P contains a ultraviolet absorber (E), it is preferable that content of a ultraviolet absorber (E) is 0.1 mass part or more with respect to 100 mass parts of (meth)acrylic acid ester polymers (A), Especially 0.5 mass part It is preferable that it is more than it, and it is more preferable that it is 1.0 mass part or more. Moreover, it is preferable that the said content is 15 mass parts or less, It is more preferable that it is 8 mass parts or less, It is especially preferable that it is 5 mass parts or less, Furthermore, it is preferable that it is 2 mass parts or less. When content of a ultraviolet absorber (E) is the said range, an adhesive layer becomes a thing easy to exhibit favorable ultraviolet absorptivity.

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

(2) Preparation of adhesive composition P

Adhesive composition P, while mixing (meth)acrylic acid ester polymer (A) obtained by manufacturing (meth)acrylic acid ester polymer (A), and rust preventive agent (B), depending on necessity, crosslinking agent (C), silane It can manufacture by adding additives, such as a compound (D) and a ultraviolet absorber (E).

A (meth)acrylic acid ester polymer (A) can be manufactured by superposing|polymerizing the mixture of the monomer which comprises a polymer by a normal radical polymerization method. It is preferable to perform superposition|polymerization of a (meth)acrylic acid ester polymer (A) by the solution polymerization method using a polymerization initiator as needed. By superposing|polymerizing the (meth)acrylic acid ester polymer (A) by the solution polymerization method, high molecular weight-ization of the polymer obtained and adjustment of molecular weight distribution become easy, and it becomes possible to reduce the production|generation of a low molecular weight body. For this reason, even when the gel fraction is made comparatively small and the degree of crosslinking is loosened, it is hard to produce the bias|inclination of the adhesive accompanying repeated bending|flexion, and the adhesive excellent in bending resistance is easy to be obtained.

As a polymerization solvent used by the solution polymerization method, 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. As the azo compound, for example, 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 1,1'-azobis(cyclohexane1-carbonone) Tril), 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (2,4-dimethyl-4-methoxyvaleronitrile), dimethyl 2,2'- Azobis(2-methylpropionate), 4,4'-azobis(4-cyanovaleric acid), 2,2'-azobis(2-hydroxymethylpropionitrile), 2,2'- azobis[2-(2-imidazolin-2-yl)propane] etc. are mentioned.

Examples of the organic peroxide include benzoyl peroxide, t-butyl perbenzoate, cumene hydroperoxide, diisopropyl peroxydicarbonate, di-n-propyl peroxydicarbonate, and di(2-ethoxyethyl)peroxydicarbonate. , t-butylperoxyneodecanoate, t-butylperoxypivalate, (3,5,5-trimethylhexanoyl)peroxide, dipropionylperoxide, diacetyl peroxide, and the like.

Moreover, in the said 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, in a solution of the (meth)acrylic acid ester polymer (A), a rust preventive agent (B), optionally a crosslinking agent (C), a silane compound (D), and an ultraviolet absorber (E) Additives, such as, a dilution solvent, etc. are added, and the adhesive composition P (coating solution) diluted with a solvent is obtained by fully mixing.

In addition, in any of the above components, when using a solid one, or when precipitation occurs when mixed with other components in an undiluted state, the component is dissolved or diluted in a diluting solvent in advance alone and then , and may be mixed with other components.

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

The concentration and viscosity of the thus prepared coating solution may be within a range that can be coated, and is not particularly limited, and may be appropriately selected depending on the situation. For example, it is diluted so that the density|concentration of the adhesive composition P may become 10-60 mass %. In addition, when obtaining a coating solution, addition of a diluent solvent etc. is not a necessary condition, and as long as the adhesive composition P is a coating-able viscosity etc., it is not necessary to add a diluent solvent. In this case, the adhesive composition P turns into a coating solution which uses the polymerization solvent of the (meth)acrylic acid ester polymer (A) as a dilution solvent as it is.

(3) Preparation of adhesive

The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer 11 in the present embodiment is preferably formed by crosslinking the pressure-sensitive adhesive composition P. Crosslinking of the adhesive composition P can be usually performed by heat treatment. Moreover, this heat processing can also serve as a drying process at the time of volatilizing a dilution solvent etc. from the coating film of the adhesive composition P apply|coated to the desired object.

It is preferable that it is 50-150 degreeC, and, as for the heating temperature of heat processing, it is especially preferable that it is 70-120 degreeC. Moreover, it is preferable that they are 10 second - 10 minutes, and, as for heating time, it is especially preferable that they are 50 second - 2 minutes.

After the heat treatment, if necessary, a curing period of about 1 to 2 weeks may be provided at normal temperature (eg, 23°C, 50%RH). When this curing period is required, an adhesive is formed after completion|finish of heat processing, when a curing period is unnecessary, after a curing period passes.

By said heat treatment (and curing), the (meth)acrylic acid ester polymer (A) is fully crosslinked via a crosslinking agent (C), a crosslinked structure is formed, and an adhesive is obtained.

(4) the thickness of the pressure-sensitive adhesive layer

As a lower limit, the thickness (value measured according to JIS K7130) of the pressure-sensitive adhesive layer 11 in the pressure-sensitive adhesive sheet 1 according to the present embodiment is preferably 1 µm or more, more preferably 5 µm or more, particularly 10 It is preferable that it is more than micrometer, Furthermore, it is preferable that it is 18 micrometers or more, and it is preferable that it is 22 micrometers or more. If the lower limit of the thickness of the pressure-sensitive adhesive layer 11 is the above, it is easy to exhibit the desired adhesive force, and since the pressure-sensitive adhesive layer in which the rust preventive agent is segregated on the surface layer can sufficiently cover the electrode, a more excellent migration prevention effect can be exhibited.

Further, the thickness of the pressure-sensitive adhesive layer 11 is preferably 100 µm or less as an upper limit, more preferably 60 µm or less, and particularly preferably 40 µm or less, from the viewpoint of obtaining a thinner repetitive bending device, further It is preferable that it is 30 micrometers or less. If the upper limit of the thickness of the adhesive layer 11 is the above, it can be made into the thing more excellent in the bending resistance by repeated bending. Moreover, since the absolute amount of the rust preventive agent (B) contained in the adhesive layer 11 can be decreased, the color change of the wiring resulting from the rust preventive agent (B) can be suppressed. Moreover, the adhesive layer 11 may be formed in a single layer, and may be formed by laminating|stacking multiple layers.

1-2. release sheet

The release sheets 12a and 12b protect the pressure-sensitive adhesive layer 11 until the pressure-sensitive adhesive sheet 1 is used, and are peeled off when the pressure-sensitive adhesive sheet 1 (the pressure-sensitive adhesive layer 11) is used. In the pressure-sensitive adhesive sheet 1 according to the present embodiment, one or both of the release sheets 12a and 12b are not necessarily required.

As the release sheets 12a and 12b, for example, a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, a polymethylpentene film, a polyvinyl chloride film, a vinyl chloride copolymer film, a polyethylene terephthalate film, a polyethylene Naphthalate film, polybutylene terephthalate film, polyurethane film, ethylene vinyl acetate film, ionomer resin film, ethylene/(meth)acrylic acid copolymer film, ethylene/(meth)acrylic acid ester copolymer film, polystyrene film, poly A carbonate film, a polyimide film, a fluororesin film, etc. are used. Moreover, these crosslinked films are also used. Moreover, these laminated|multilayer films may be sufficient.

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

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

2. Physical properties (adhesion)

The lower limit of the adhesive force of the pressure-sensitive adhesive sheet 1 to soda lime glass is preferably 1 N/25 mm or more, more preferably 10 N/25 mm or more, and particularly preferably 20 N/25 mm or more, Furthermore, it is preferable that it is 25 N/25 mm or more, and it is preferable that it is 29 N/25 mm or more. If the lower limit of the adhesive force with respect to the soda-lime glass of the adhesive sheet 1 is the above, it will be more excellent in bending resistance. On the other hand, although it does not restrict|limit especially about the said upper limit of adhesive force, Rework property may be required. From such a viewpoint, it is preferable that the said adhesive force is 100 N/25 mm or less, It is more preferable that it is 60 N/25 mm or less, It is especially preferable that it is 40 N/25 mm or less, It is especially preferable that it is 35 N/25 mm or less. In addition, the adhesive force in this specification basically means the adhesive force measured by the 180 degree peeling method according to JIS Z0237:2009, A specific test method is as showing in the test example mentioned later.

3. Preparation of adhesive sheet

As one manufacturing example of the adhesive sheet 1, the case where the said adhesive composition P is used is demonstrated. The coating liquid of the adhesive composition P is apply|coated to the peeling surface of one peeling sheet 12a (or 12b), heat-processing is performed, the adhesive composition P is thermally crosslinked, and after forming an application layer, the other side to the application layer. The release surface of the release sheet 12b (or 12a) of When a curing period is required, by providing a curing period, when a curing period is unnecessary, the said application layer becomes the adhesive layer 11 as it is. Thereby, the said adhesive sheet 1 is obtained. About the conditions of heat processing and curing, it is as above-mentioned.

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

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

[Repeated bending laminated member]

As shown in FIG. 2 , the repeated flexural lamination member 2 according to the present embodiment includes a first flexible member 21 (one flexible member), a second flexible member 22 (another flexible member), It is located between them, and the adhesive layer 11 which bonds the 1st flexible member 21 and the 2nd flexible member 22 together is provided and it is comprised.

The pressure-sensitive adhesive layer 11 in the repeated bending lamination member 2 is the pressure-sensitive adhesive layer 11 of the pressure-sensitive adhesive sheet 1 described above.

The repeated bending laminated member 2 is the repetitive bending device itself or a member constituting a part of the repetitive bending device. The repetitive flexion device is preferably, but is not limited to, a display (repetitive flexion display) capable of repeated bending (including folding). Examples of such a repetitive bending device include an organic electroluminescence (organic EL) display, an electrophoretic display (electronic paper), a liquid crystal display using a plastic substrate (film) as a substrate, a foldable display, and the like. and a touch panel may be sufficient.

The first flexible member 21 and the second flexible member 22 are members capable of repeated bending (including folding), for example, a cover film, a gas barrier film, a hard coat film, a polarizing film ( Polarizing plate), polarizer, retardation film (retardation plate), viewing angle compensation film, brightness enhancement film, contrast enhancement film, diffusion film, transflective film, electrode film, transparent conductive film, metal mesh film, flexible glass, film sensor (touch sensor film), liquid crystal polymer film, light emitting polymer film, film liquid crystal module, organic EL module (organic EL film, organic EL device), electronic paper module (film electronic paper), TFT (Thin Film Transistor) substrate, etc. can

Here, it is preferable that the 1st flexible member 21 and/or the 2nd flexible member 22 has an electrode on the surface of the side (adhesive layer 11 side) to be bonded at least, It consists of a metal or a metal oxide. It is preferable to have an electrode. Examples of the flexible member having an electrode include a film sensor, an electrode film, a metal mesh film, a metal nanowire film, and a wire grid polarizing film. According to the adhesive layer 11 in this embodiment, even when it contacts the flexible member which has an electrode, the outstanding migration prevention effect can be exhibited and the resistance value change of an electrode can be suppressed.

Examples of the electrode made of the metal include metal wirings (including those in the form of mesh, grid, and nanowire) made of silver, a silver alloy, copper, a copper alloy, or the like. In particular, what constitutes an electrode of a touch panel is exemplified preferably, and specifically, a metal wiring included in a film sensor is preferably exemplified. Among the said metal wirings, the metal wiring which consists of nanoparticles of silver or a silver alloy is preferable, and especially as a silver alloy, the silver alloy metal wiring by which palladium and copper were added to silver is preferable. With respect to these metal wirings, the outstanding migration prevention effect by the adhesive layer 11 is exhibited.

As an electrode which consists of the said metal oxide, what patterned the transparent conductive film which consists of metal oxides, such as tin-doped indium oxide (ITO) and zinc oxide, for example is mentioned. Among the above, what patterned the transparent conductive film which consists of ITO especially is preferable, and the outstanding migration prevention effect by the adhesive layer 11 is easy to exhibit with respect to the said ITO transparent conductive film.

When the electrode is a wiring, the wiring width is preferably 100 µm or less, more preferably 60 µm or less, particularly preferably 30 µm or less, further preferably 20 µm or less, and particularly preferably 11 µm or less. do. Moreover, 1 micrometer or more of the said wiring width is preferable, 2 micrometers or more are more preferable, 4 micrometers or more are especially preferable, and 8 micrometers or more are further more preferable. Since the adhesive layer 11 of this embodiment can exhibit the outstanding migration prevention effect, contributing to refinement|miniaturization and pitch reduction of an electrode as the wiring width is the said range, it contributes to the connection reliability improvement of an electrode, etc.

When the electrodes are wirings, the distance between the wirings (hereinafter, sometimes referred to as "distance between wirings") is preferably 100 µm or less, more preferably 60 µm or less, and particularly preferably 30 µm or less. , more preferably 20 µm or less, and particularly preferably 11 µm or less. Moreover, 1 micrometer or more is preferable, and, as for the said distance between wirings, 2 micrometers or more are more preferable, 4 micrometers or more are especially preferable, and 8 micrometers or more are further more preferable. Since the adhesive layer 11 of this embodiment can exhibit the outstanding migration prevention effect, contributing to refinement|miniaturization and narrow pitch of an electrode as the distance between wirings is the said range, it contributes to the improvement of connection reliability of an electrode, etc.

When the electrode is a wiring, the wiring thickness is preferably 1 µm or less, more preferably 0.6 µm or less, particularly preferably 0.3 µm or less, and further preferably 0.2 µm or less. Moreover, 0.01 micrometer or more is preferable, as for the said wiring thickness, 0.05 micrometer or more is more preferable, 0.1 micrometer or more is especially preferable, and 0.15 micrometer or more is further more preferable. Since the adhesive layer 11 of this embodiment can exhibit the more outstanding migration prevention effect, contributing to thinning of an electrode as wiring thickness is the said range, it contributes to the improvement of connection reliability of an electrode, etc.

The Young's modulus of the first flexible member 21 and the second flexible member 22 is preferably 0.1 to 10 GPa, respectively, particularly preferably 0.5 to 7 GPa, and further preferably 1.0 to 5 GPa. When the Young's modulus of the first flexible member 21 and the second flexible member 22 are within these ranges, it becomes easy to repeatedly bend each flexible member.

It is preferable that the thickness of the 1st flexible member 21 and the 2nd flexible member 22 is 10-3000 micrometers, respectively, it is especially preferable that it is 25-1000 micrometers, It is further more preferable that it is 50-500 micrometers. When the thickness of the 1st flexible member 21 and the 2nd flexible member 22 exists in such a range, it becomes easy to repeatedly bend with respect to each flexible member.

In order to manufacture the said repeated bending lamination|stacking member 2, as an example, one peeling sheet 12a of the adhesive sheet 1 is peeled, and the exposed adhesive layer 11 of the adhesive sheet 1 is converted into 1st flexibility. It is bonded to one surface of the member 21 .

Then, the other release sheet 12b is peeled from the adhesive layer 11 of the adhesive sheet 1, and the exposed adhesive layer 11 of the adhesive sheet 1 and the 2nd flexible member 22 are bonded together, , to obtain a repeated bending laminated member (2). In addition, as another example, you may change the bonding order of the 1st flexible member 21 and the 2nd flexible member 22. As shown in FIG.

[repetitive bending device]

The repeatedly flexing device according to the present embodiment is provided with the repeatedly flexed lamination member 2 described above, and may consist only of the repeated flexure lamination member 2, or may be formed of one or a plurality of repeatedly flexed lamination members 2 and another. You may be comprised by providing a flexible member. When laminating one repeatedly flexed laminating member 2 and another repeatedly flexed laminating member 2, or when laminating the repeatedly flexed laminating member 2 and another flexible member, the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet 1 described above It is preferable to laminate through (11).

In the repeated bending device according to the present embodiment, since the pressure-sensitive adhesive layer is composed of the pressure-sensitive adhesive obtained from the above-described pressure-sensitive adhesive composition P, when repeatedly bent, lines or cloudiness in the pressure-sensitive adhesive layer are suppressed, and the pressure-sensitive adhesive layer and the adherend are Generation|occurrence|production of the float in the interface with a flexible member and peeling can be suppressed. In this way, the repeated bending device according to the present embodiment is excellent in bending resistance when repeatedly bent at a predetermined portion. In addition, when the first flexible member 21 and/or the second flexible member 22 constituting the repeatedly flexural lamination member 2 has an electrode at least on the surface of the side to be bonded (adhesive layer 11 side) Also, an excellent migration prevention effect can be exhibited, and a change in the resistance value of the electrode can be suppressed.

The repetitive bending device as an example in this embodiment is shown in FIG. In addition, the repetitive bending device which concerns on this invention is not limited to the said repetitive bending device.

As shown in FIG. 3, the repetitive bending device 3 which concerns on this embodiment is in order from the top, the cover film 31, the 1st adhesive layer 32, the polarizing film 33, and the 2nd The pressure-sensitive adhesive layer 34, the touch sensor film 35, the third pressure-sensitive adhesive layer 36, the organic EL element 37, the fourth pressure-sensitive adhesive layer 38, and the TFT substrate 39 are laminated. do. Said cover film 31, the polarizing film 33, the touch sensor film 35, the organic electroluminescent element 37, and the TFT board|substrate 39 correspond to a flexible member.

At least any one of the first adhesive layer 32 , the second adhesive layer 34 , the third adhesive layer 36 , and the fourth adhesive layer 38 is the adhesive layer 11 of the adhesive sheet 1 described above. )to be. Any two or more layers of the first pressure-sensitive adhesive layer 32 , the second pressure-sensitive adhesive layer 34 , the third pressure-sensitive adhesive layer 36 and the fourth pressure-sensitive adhesive layer 38 , the pressure-sensitive adhesive layer 11 of the pressure-sensitive adhesive sheet 1 described above It is preferable that all of the pressure-sensitive adhesive layers 32 , 34 , 36 and 38 are the pressure-sensitive adhesive layers 11 of the pressure-sensitive adhesive sheet 1 .

Here, for example, when the touch sensor film 35 has an electrode, in particular, when an electrode is provided on the second pressure sensitive adhesive layer 34 side, at least the second pressure sensitive adhesive layer 34 performs migration. It is preferable that it is the adhesive layer 11 of the adhesive sheet 1 mentioned above from a viewpoint which can suppress effectively.

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

For example, either one or both of the release sheets 12a and 12b in the pressure-sensitive adhesive sheet 1 may be omitted, or a desired flexible member may be laminated in place of the release sheets 12a and/or 12b.

(Example)

Hereinafter, the present invention will be described in more detail 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 polymer (A)

60 parts by mass of 2-ethylhexyl acrylate, 34 parts by mass of n-butyl acrylate, 5 parts by mass of N-acryloylmorpholine and 1 part by mass of acrylic acid 2-hydroxyethyl are copolymerized by a solution polymerization method, (meth)acrylic acid ester A polymer (A) was prepared. When the molecular weight of this (meth)acrylic acid ester polymer (A) was measured by the method mentioned later, the weight average molecular weight (Mw) was 700,000.

2. Preparation of adhesive composition

100 parts by mass of the (meth)acrylic acid ester polymer (A) obtained in the step 1 (solid content conversion; the same applies below) and 1-[N,N-bis(2-ethylhexyl)aminomethyl]methyl as a rust preventive agent (B) 0.05 parts by mass of benzotriazole, 0.25 parts by mass of trimethylolpropane adduct xylylene diisocyanate (C1) as a crosslinking agent (C), and 3-glycidyloxypropyltrimethoxysilane (D1) as a silane compound (D) 0.25 mass parts was mixed, and the coating solution of the adhesive composition was obtained by fully stirring and diluting with methyl ethyl ketone.

3. Preparation of adhesive sheet

The coating solution of the obtained adhesive composition was applied to the peeling-treated side of a medium-peelable release sheet (manufactured by Lintec, product name "SP-PET752150"), in which one side of a polyethylene terephthalate film was peeled off with a silicone-based release agent, with a knife coater. And with respect to the application layer, it heat-processed at 90 degreeC for 1 minute, and the application layer was formed.

Next, the application layer on the medium release type release sheet obtained above, and the light release type release sheet (manufactured by Lintec, product name "SP-PET381130") in which one side of the polyethylene terephthalate film was peeled off with a silicone type release agent was applied to the light release type release sheet. A pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer having a thickness of 25 µm, that is, a heavy release type release sheet/adhesive layer (thickness) : 25 µm)/a pressure-sensitive adhesive sheet having a structure of a light-peelable release sheet was produced. In addition, based on JISK7130, the thickness of an adhesive layer is the value measured using the static pressure thickness meter (The Techlock company make, product name "PG-02").

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

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

2EHA: 2-ethylhexyl acrylate

BA: n-butyl acrylate

ACMO: N-acryloylmorpholine

MMA: methyl methacrylate

IBXA: isobornyl acrylate

HEA: Acrylic acid 2-hydroxyethyl

4HBA: 4-hydroxybutyl acrylate

AA: acrylic acid

[Crosslinking agent (C)]

C1: trimethylolpropane adduct xylylene diisocyanate

C2: 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane

[Silane compound (D)]

D1: 3-glycidyloxypropyltrimethoxysilane

D2: an organosilicon compound represented by the following structural formula (II)

[Tue 2]

[Ultraviolet absorbent (E)]

E1: Benzotriazole-based UV absorber (manufactured by BASF Japan, product name “TINUVIN 384-2”)

E2: 2,2-dihydroxy-4-methoxybenzophenone

[Examples 2 to 9, Comparative Examples 1 to 7]

The type and ratio of each monomer constituting the (meth)acrylic acid ester polymer (A), the weight average molecular weight (Mw) of the (meth)acrylic acid ester polymer (A), the compounding amount of the rust inhibitor (B), the type of the crosslinking agent (C), and Except changing the compounding quantity and the kind of a silane compound (D) as Table 1 showed, it carried out similarly to Example 1, and produced the adhesive sheet. Moreover, about Examples 4 and 5, the ultraviolet absorber (E) was further added.

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

<Measurement conditions>

・GPC measuring device: Tosoh Corporation, HLC-8020

・GPC column (passed in the following order): manufactured by Tosoh Corporation

TSK guard column HXL-H

TSK gel GMHXL (×2)

TSK gel G2000HXL

・Measurement solvent: tetrahydrofuran

・Measurement temperature: 40℃

[Test Example 1] (Calculation of glass transition temperature (Tg))

The glass transition temperature (Tg; ° C.) of the (meth)acrylic acid ester polymer (A) prepared in Examples and Comparative Examples, the glass transition temperature (Tg) of each monomer constituting the (meth)acrylic acid ester polymer (A) as a homopolymer ), it was calculated by the FOX equation. A result is shown in Table 1.

[Test Example 2] (Measurement of water absorption)

The light-peelable release sheet was peeled from the pressure-sensitive adhesive sheet obtained in Examples and Comparative Examples, and the exposed pressure-sensitive adhesive layer was treated with a polyethylene terephthalate (PET) film having an easily adhesive layer (manufactured by Toyobo Corporation, product name "Cosmoshine PET100A4360", thickness : 100 micrometers), it bonded together to the easily adhesive layer, and obtained the laminated body which consists of a heavy-release type|mold peeling sheet/adhesive layer/PET film. The obtained laminate was cut out to 150 mm width and 150 mm length, and it was set as the measurement sample. The heavy release type release sheet was peeled off from the measurement sample before the test, and the mass before the test was measured.

Said measurement sample was injected|thrown-in in 60 degreeC and the moist heat environment of 90 %RH for 24 hours. Within 10 minutes after taking out, the heavy release type release sheet was peeled from the measurement sample after the test, and the mass after the test was measured. From the obtained measured value, the water absorption rate (%) was computed by following formula (1). A result is shown in Table 2.

Absorption rate (%) = ｛ (mass after test - mass before test)/mass before test x x 100 . . . (One)

[Test Example 3] (Measurement of storage modulus G')

Multiple layers of the pressure-sensitive adhesive layers of the pressure-sensitive adhesive sheets produced in Examples and Comparative Examples were laminated to form a 3 mm-thick laminate. A cylindrical body (height 3 mm) of diameter 8 mm was punched out from the laminated body of the obtained adhesive layer, and this was made into the sample.

About the said sample, in accordance with JIS K7244-1, using a viscoelasticity measuring apparatus (manufactured by Anton Paar, product name "MCR301"), the storage elastic modulus G' was measured by the torsional shearing method under the following conditions, and -20 degreeC The storage elastic modulus G'(-20) in , the storage elastic modulus G'(23) at 23 degreeC, and the storage elastic modulus G'(50) (MPa) at 50 degreeC were acquired. A result is shown in Table 2.

Measurement frequency: 1Hz

Measuring temperature: -20℃ ~ 150℃

[Test Example 4] (Measurement of gel fraction)

The pressure-sensitive adhesive sheets produced in Examples and Comparative Examples are cut to a size of 80 mm × 80 mm, the pressure-sensitive adhesive layer is wrapped with a polyester mesh (product name: Tetron mesh #200), and the mass is weighed with a precision balance, , The mass of the adhesive alone was calculated by subtracting the mass of the mesh alone. Let the mass at this time be M1.

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

[Test Example 5] (Measurement of adhesive force)

The light-peelable release sheet was peeled from the pressure-sensitive adhesive sheet obtained in Examples and Comparative Examples, and the exposed pressure-sensitive adhesive layer was placed on a polyethylene terephthalate (PET) film having an easily adhesive layer (manufactured by Toyobo Corporation, product name “Cosmoshine PET100A4360”, thickness: 100 μm) ), it bonded to the easily adhesive layer of ), and the laminated body of heavy peeling type|mold peeling sheet/adhesive layer/PET film was obtained. The obtained laminate was cut into 25 mm width and 110 mm length.

In an environment of 23°C and 50% RH, the heavy release type release sheet was peeled off from the laminate, and the exposed pressure-sensitive adhesive layer was affixed to soda lime glass (manufactured by Nippon Itagaras Co., Ltd.), with an autoclave manufactured by Kurihara Seisakusho Corporation. At 0.5 Mpa and 50 degreeC, it pressurized for 20 minutes. Then, after leaving it to stand under the conditions of 23 degreeC, 50%RH for 24 hours, using the tensile tester (Orientec company make, product name "Tensiron"), the peeling rate of 300 mm/min and the peeling angle of 180 degree|times, PET The adhesive force (N/25mm) at the time of peeling the laminated body of a film and an adhesive layer from a to-be-adhered body was measured. Conditions other than those described here were measured in accordance with JIS Z0237:2009. A result is shown in Table 2.

[Test Example 6] (Evaluation of bending resistance)

The light-peelable release sheet was peeled from the pressure-sensitive adhesive sheet produced in Examples and Comparative Examples, and the exposed pressure-sensitive adhesive layer was affixed to a polyethylene terephthalate (PET) film (manufactured by Toyobo, product name "Cosmoshine PET50A4360", 50 µm). Then, the heavy release type release sheet was peeled off, and the exposed adhesive layer was affixed to another polyethylene terephthalate (PET) film (made by Toyobo, product name "Cosmoshine PET125A4360", 125 µm). And after pressurizing at 0.5 MPa and 50 degreeC for 20 minutes with the autoclave manufactured by Kurihara Seisakusho, it was left to stand on 23 degreeC and conditions of 50 %RH for 24 hours. Thus, the laminated body which consists of PET film (50 micrometers)/adhesive layer (25 micrometers)/PET film (125 micrometers) obtained in this way was cut out to 40 mm width and 150 mm length, and this was made into the sample.

As shown in Fig. 4, the obtained sample was fixed to two holding plates of a planar body no-load U-shaped expansion and contraction testing machine (manufactured by Yuasa Systems Co., Ltd., product name "DLDMLH-FS"). And it was made to bend repeatedly under the following conditions. After the repeated bending test, the appearance of the bent portion of the sample was visually observed, and the bending resistance was evaluated based on the following criteria. A result is shown in Table 2.

<Test conditions>

Bending direction: bent so that the PET film (125 μm) is on the outside and the other PET film (50 μm) is on the inside

Minimum bending diameter: 4mmφ

Stroke: 80mm

Bending speed: 60rpm

Number of bends: 100,000 or 300,000

Test temperature: 23℃

<Evaluation criteria for bending resistance>

○: There is no change from before the test.

(triangle|delta): The line|wire of a bending part can be visually recognized clearly, and there is no lifting and peeling of an adhesive.

x: The line|wire of a bending part can be visually recognized clearly, and there exists floating-off peeling of an adhesive.

[Test Example 7] (Evaluation of the effect of preventing migration using a metal wiring electrode plate)

(1) Preparation of metal wiring electrode plate

On the easily adhesive side of a polyethylene terephthalate (PET) film (manufactured by Toray Corporation, product name "Lumira U48", thickness: 125 µm), on which one side has been easily adhesively treated, a silver paste (manufactured by Toyochem, Product name "RA FS088") was applied so that the wiring of the positive electrode and the wiring of the negative electrode were linearly and parallel to each other. Then, the electrode plate (metal wiring electrode plate) which has silver wiring was obtained by heat-processing and hardening at 135 degreeC for 30 minutes. The wiring width of the anode and the cathode was 10 mu m, the distance between the wirings was 10 mu m, and the wiring thickness was 0.15 mu m.

(2) Evaluation of migration prevention effect

The light-peelable release sheet was peeled from the pressure-sensitive adhesive sheet obtained in Examples and Comparative Examples, and the exposed pressure-sensitive adhesive layer was placed on a polyethylene terephthalate (PET) film having an easily adhesive layer (manufactured by Toyobo Corporation, product name “Cosmoshine PET100A4360”, thickness: 100 µm) ), it bonded to the easily adhesive layer of ), and the laminated body of heavy peeling type|mold peeling sheet/adhesive layer/PET film was obtained. Then, the heavy release type release sheet was peeled from the laminate, and the exposed adhesive layer was affixed on the wiring of the anode and the wiring of the cathode in the metal wiring electrode plate. And after autoclaving for 20 minutes on the conditions of 50 degreeC and 0.5 Mpa, it left to stand under the conditions of 23 degreeC and 50 %RH for 24 hours, and this was set as the metal wiring electrode plate sample.

The said metal wiring electrode plate sample was left still on wet heat conditions of 105 degreeC and 100%RH for 3 hours, and the voltage of 5V was applied between the electrodes in that state. Then, the wiring of the anode and the wiring of the cathode were observed with an optical microscope (magnification: 10 times), and the migration prevention effect was evaluated based on the evaluation criteria shown below. A result is shown in Table 2. Moreover, also in the sample of any Example and a comparative example, problems, such as a float, peeling, and generation|occurrence|production of a bubble, were not recognized.

(circle): The dissolution of the wiring of an anode and formation of a dendrite in the wiring of a cathode are not seen at all.

x: Dissolution of the wiring of the anode or formation of dendrites in the wiring of the cathode is observed.

[Test Example 8] (Evaluation of resistance value change using metal wiring electrode plate)

A digital tester (manufactured by Hioki Denki, product name "Digital High Tester 3802-50") was used by applying a voltage of 5 V between the wiring of the anode and the wiring of the cathode for the sample of the metal wiring electrode plate produced in the same manner as in Test Example 7 Thus, the initial resistance value R ⁰ (Ω) was measured.

Next, the said metal wiring electrode plate sample was inject|thrown-in to the moist heat environment of 105 degreeC and 100%RH for 3 hours, and the voltage of 5V was applied between the electrodes in that state. Then, it left still in the normal temperature and humidity environment of 23 degreeC and 50 %RH for 24 hours, it carried out similarly to the said initial resistance value, and measured the resistance value (ohm). This was made into the resistance value R after an endurance test. From the obtained measured value, resistance value change rate (%) was computed by the following formula.

Resistance change rate (%) = ｛(R-R ⁰ )/R ⁰ ｝×100

And based on the resistance value change rate calculated above, the following reference|standard evaluated the resistance value change. A result is shown in Table 2.

○: resistance value change rate less than 100%

(triangle|delta): resistance value change rate 100% or more and less than 500%

x: resistance value change rate is 500% or more

[Test Example 9] (Evaluation of resistance value change using ITO vapor deposition film)

Through the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet obtained in Examples and Comparative Examples, soda-lime glass (length 70 mm × width 150 mm × thickness 1.0 mm; manufactured by Nippon Itagarasu Co., Ltd.) and an ITO vapor deposition film (manufactured by Oike Kogyo Co., Ltd., product name) "Tetraite TCF KH150NMH2-125-U6/T2", the ITO vapor deposition film side was in contact with the pressure-sensitive adhesive layer) was bonded. And after autoclaving for 20 minutes on 50 degreeC and the conditions of 0.5 Mpa, it left to stand on 23 degreeC and conditions of 50 %RH for 24 hours, and the ITO vapor deposition film sample was obtained.

About the said ITO vapor deposition film sample, the initial resistance value R ⁰ ((ohm)) was measured using the non-contact resistance measuring instrument (The Nafson company make, product name "EC-80").

Next, the said ITO vapor deposition film sample was thrown into the moist heat environment of 85 degreeC and 85 %RH for 1000 hours, or the high temperature environment of 95 degreeC for 1000 hours. Then, it left still in the normal temperature and humidity environment of 23 degreeC and 50 %RH for 24 hours, it carried out similarly to the said initial resistance value, and measured the resistance value (Ω), respectively. This was made into the resistance value R after an endurance test. From the obtained measured value, resistance value change rate (%) was computed by the same formula as Test Example 8.

And based on the resistance value change rate calculated above, the following reference|standard evaluated the resistance value change. A result is shown in Table 2.

○: resistance value change rate less than 100%

(triangle|delta): resistance value change rate 100% or more and less than 300%

x: resistance value change rate is 300% or more

[Table 1]

[Table 2]

As Table 2 shows, the adhesive sheet of an Example was excellent in bending resistance. Moreover, according to the adhesive sheet of an Example, migration could be prevented and the change of the resistance value of a metal wiring electrode plate and an ITO vapor deposition film was suppressed.

The pressure-sensitive adhesive sheet of the present invention is suitable for bonding one flexible member constituting a repetitive bending device and another flexible member.

1: adhesive sheet
11: adhesive layer
12a, 12b: release sheet
2: Repeated bending laminated member
21: first flexible member
22: second flexible member
3: Repeat flexion device
31: cover film
32: first pressure-sensitive adhesive layer
33: polarizing film
34: second pressure-sensitive adhesive layer
35: touch sensor film
36: third pressure-sensitive adhesive layer
37: organic EL element
38: fourth pressure-sensitive adhesive layer
39: TFT substrate
S: test piece
P: retaining plate

Claims (14)

A pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer for bonding one flexible member constituting a device to be repeatedly bent and another flexible member, the pressure-sensitive adhesive sheet comprising:
The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer contains a rust preventive,
The water absorption rate represented by following formula (1) at the time of performing the test which inject|throws-in the said adhesive layer in 60 degreeC and the moist heat environment of 90 %RH for 24 hours is 0.5 % or less, The adhesive sheet characterized by the above-mentioned.
Absorption rate (%) = ｛ (mass after test - mass before test)/mass before test x x 100 . . . (One) According to claim 1,
The storage elastic modulus G'(-20) in -20 degreeC of the said adhesive is 0.01 MPa or more and 10 MPa or less, The adhesive sheet characterized by the above-mentioned. According to claim 1,
The storage elastic modulus G' (23) in 23 degreeC of the said adhesive is 0.01 MPa or more and 0.5 MPa or less, The adhesive sheet characterized by the above-mentioned. According to claim 1,
The storage elastic modulus G'(50) in 50 degreeC of the said adhesive is 0.001 MPa or more and 0.2 MPa or less, The adhesive sheet characterized by the above-mentioned. According to claim 1,
A gel fraction of the pressure-sensitive adhesive is 40% or more and 100% or less. According to claim 1,
Content of the said rust preventive agent in the said adhesive is 0.001 mass % or more and 1 mass % or less, The adhesive sheet characterized by the above-mentioned. According to claim 1,
The said rust preventive agent is an azole, The adhesive sheet characterized by the above-mentioned. According to claim 1,
The pressure-sensitive adhesive is an acrylic pressure-sensitive adhesive sheet. According to claim 1,
The said adhesive is obtained from the adhesive composition containing a (meth)acrylic acid ester polymer (A) and a rust preventive agent (B), The adhesive sheet characterized by the above-mentioned. 10. The method of claim 9,
The glass transition temperature (Tg) of the said (meth)acrylic acid ester polymer (A) is -100 degreeC or more and -45 degrees C or less, The adhesive sheet characterized by the above-mentioned. 10. The method of claim 9,
The said (meth)acrylic acid ester polymer (A) contains 0.1 mass % or more and 12 mass % or less of a hydroxyl-containing monomer as a monomer unit which comprises the said polymer, The adhesive sheet characterized by the above-mentioned. According to claim 1,
Two release sheets are provided,
The pressure-sensitive adhesive layer is sandwiched between the two release sheets so as to be in contact with the release surfaces of the two release sheets. one flexible member and another flexible member constituting the device to be repeatedly bent;
A repeated flexural lamination member provided with a pressure-sensitive adhesive layer for bonding the one flexible member and the other flexible member to each other,
Any one or more of the said one flexible member and the said other flexible member has an electrode which consists of a metal or a metal oxide on the surface on the side to be bonded at least,
The said adhesive layer consists of the adhesive layer of the adhesive sheet in any one of Claims 1-12, The repeating bending lamination|stacking member characterized by the above-mentioned. A repetitive bending device comprising the repetitive bending lamination member according to claim 13.

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