JP6866880B2 - Photo-curable adhesive sheet - Google Patents

Description

The present invention is an adhesive sheet used for laminating a resin member having an ultraviolet ray blocking property that does not transmit ultraviolet rays, and has a performance of curing by irradiating light (referred to as "photocuring property"). Regarding photocurable adhesive sheets.

In recent years, in order to improve the visibility of an image display device, an image display panel such as a liquid crystal display (LCD), a plasma display (PDP), or an electroluminescence display (ELD) and protection arranged on the front side (visual side) thereof. By filling the gap between the panel and the touch panel member with an adhesive, the reflection of the incident light and the emitted light from the display image at the air layer interface is suppressed.

As a method of filling the gaps between the constituent members of the image display device with an adhesive, there is a method of filling the gaps with a liquid adhesive resin composition containing an ultraviolet curable resin and then irradiating the voids with ultraviolet rays to cure the voids. It is known (Patent Document 1).

Further, a method of filling the gaps between the constituent members of the image display device with an adhesive sheet is also known. For example, Patent Document 2 discloses a method in which an adhesive sheet primaryly crosslinked by ultraviolet rays is attached to an image display device constituent member, and then the adhesive sheet is irradiated with ultraviolet rays via the image display device constituent member to be secondarily cured. ..

In Patent Document 3, when an image display device component having a stepped portion on the bonding surface is bonded via a transparent double-sided adhesive sheet, the image display device component can be filled to every corner following the stepped portion. Moreover, as a new transparent double-sided adhesive sheet that can alleviate the distortion that occurs in the adhesive sheet and maintain foam resistance in high temperature and high humidity environments without impairing maneuverability, one or more types (polymer). ) Acrylic acid ester (co) polymer, an ultraviolet polymerization initiator (A) having a molar absorption coefficient of 10 or more at a wavelength of 365 nm and a molar absorption coefficient of 0.1 or less at a wavelength of 405 nm, and a molar absorption coefficient of 405 nm. It contains a visible photopolymerization initiator (B) having a coefficient of 10 or more, and the dynamic storage elasticity (E') at 60 ° C. determined by the tensile method is determined by the dynamic storage elasticity (E') at 60 ° C. determined by the shearing method. A transparent double-sided adhesive sheet in a B stage state in which the value (E'/ G') divided by G') is 10 or more has been proposed.

International Publication No. 2010/027041 Japanese Patent No. 4971529 Japanese Unexamined Patent Publication No. 2014-152295

When two image display device components are attached using the photocurable adhesive sheet as described above, after the two image display device components are primarily attached via the adhesive sheet, one image is displayed. The adhesive sheet can be secondarily attached by irradiating ultraviolet rays from the outside of the device constituent member and curing the adhesive sheet with ultraviolet rays through the image display device constituent member.
According to such a method, it is possible to perform primary bonding while filling the unevenness of the adherend surface, and further, the adhesive reliability can be further improved by finally curing with ultraviolet rays. It is possible to achieve both "step absorption" when the adherend surface of the "bonded member") has irregularities and "foaming reliability" after bonding.

For example, in an in-vehicle image display device or the like, a resin front panel is used to prevent glass from scattering, and a resin member such as a conductive member or a polarizing plate may be arranged inside the front panel. In this case, since it is necessary to prevent deterioration such as yellowing of the resin members such as the conductive member and the polarizing plate arranged on the front panel and its inner side due to exposure to ultraviolet rays, the resin members on the side exposed to ultraviolet rays are used. An ultraviolet absorber is blended to have the ability to absorb ultraviolet rays.
However, in this case, as described above, it is not possible to irradiate ultraviolet rays from the outside of the image display device constituent member to cure the adhesive sheet with ultraviolet rays through the image display device constituent member.
Therefore, when the resin front panel is bonded, a non-photocurable pressure-sensitive adhesive sheet that is sufficiently cured to have foam resistance reliability and does not have photocurability must be used.
However, such a non-photocurable pressure-sensitive adhesive sheet is not always satisfactory in terms of step absorption.

The present invention can be bonded to a resin member having an ultraviolet ray blocking property that does not transmit ultraviolet rays, and can provide step absorption when the adherend surface of the bonded member has irregularities and foaming reliability after bonding. It provides a new adhesive sheet that can be compatible with each other.

The present invention has a resin member (X), an image display panel (P), and a photocurable pressure-sensitive adhesive sheet. The resin member (X) has a light transmittance of 10% or less at a wavelength of 365 nm. An image display panel having a light transmittance of 60% or more at a wavelength of 405 nm and having an adhesive layer (Y) having all the following characteristics (1) to (4). We propose a laminate.
(1) The gel fraction (referred to as "gel fraction before light irradiation X1") is in the range of 0 to 50%.
(2) The light transmittance at a wavelength of 390 nm is 89% or less, and the light transmittance at a wavelength of 410 nm is 80% or more.
(3) It has photocurability that is cured by irradiation with light having a wavelength of 405 nm.
(4) The photocurability in (3) above is 20% as a difference in gel fraction when light having a wavelength of 405 nm is irradiated from the outside of the resin member (X) through the resin member (X). It is a photocurable material that increases beyond that.
The present invention also has a resin member (X), an image display panel (P), and a photocurable pressure-sensitive adhesive sheet, and the resin member (X) has a light transmittance of 10% or less at a wavelength of 365 nm. In addition, the light transmittance at a wavelength of 405 nm is 60% or more, and the photocurable pressure-sensitive adhesive sheet has the following properties (1) to (3) , (5) and (6). We propose an image display panel laminate having (Y).
(1) The gel fraction (referred to as "gel fraction before light irradiation X1") is in the range of 0 to 50%.
(2) The light transmittance at a wavelength of 390 nm is 89% or less, and the light transmittance at a wavelength of 410 nm is 80% or more.
(3) It has photocurability that is cured by irradiation with light having a wavelength of 405 nm.
(5) The photocurability in (3) above is 15% or more as a difference in gel fraction when light having a wavelength of 405 nm is irradiated from the outside of the resin member (X) through the resin member (X). Increased photocurability.
(6) It is formed from a pressure-sensitive adhesive composition containing a (meth) acrylic acid ester (co) polymer, and does not contain acrylic acid as a copolymerization component of the (co) polymer.
The present invention also has a resin member (X), an image display panel (P), and a photocurable pressure-sensitive adhesive sheet, and the resin member (X) has a light transmittance of 10% or less at a wavelength of 365 nm. In addition, the light transmittance at a wavelength of 405 nm is 60% or more, and the photocurable pressure-sensitive adhesive sheet has the following properties (1) to (3) , (5) and (7). We propose an image display panel laminate having (Y).
(1) The gel fraction (referred to as "gel fraction before light irradiation X1") is in the range of 0 to 50%.
(2) The light transmittance at a wavelength of 390 nm is 89% or less, and the light transmittance at a wavelength of 410 nm is 80% or more.
(3) It has photocurability that is cured by irradiation with light having a wavelength of 405 nm.
(5) The photocurability in (3) above is 15% or more as a difference in gel fraction when light having a wavelength of 405 nm is irradiated from the outside of the resin member (X) through the resin member (X). Increased photocurability .
(7) It is formed from a pressure-sensitive adhesive composition containing a (meth) acrylic acid ester (co) polymer, and the pressure-sensitive adhesive composition does not contain an epoxy-based cross-linking agent.
The present invention also has a resin member (X), an image display panel (P), and a photocurable pressure-sensitive adhesive sheet, and the resin member (X) has a light transmittance of 10% or less at a wavelength of 365 nm. In addition, the photocurable pressure-sensitive adhesive sheet has a light transmittance of 60% or more at a wavelength of 405 nm, and the photocurable pressure-sensitive adhesive sheet has an pressure-sensitive adhesive layer (Y) having all the following properties (1) to (3) and (8). We propose an image display panel laminate having.
(1) The gel fraction (referred to as "gel fraction before light irradiation X1") is in the range of 0 to 60%.
(2) The light transmittance at a wavelength of 390 nm is 89% or less, and the light transmittance at a wavelength of 410 nm is 80% or more.
(3) It has photocurability that is cured by irradiation with light having a wavelength of 405 nm.
(8) Temporarily cured by light irradiation.

Since the photocurable pressure-sensitive adhesive sheet proposed by the present invention has a gel content of 0 to 60% before photocuring, it is possible to obtain step absorption that fills steps such as irregularities on the adherend surface, while having a wavelength of 390 nm. Since the light transmittance in the above is 89% or less and the resin member (X) to be bonded has a photocurability that is cured by irradiation with light having a wavelength of 405 nm, the light transmittance at a wavelength of 365 nm is 10. % Or less, and even if the light transmittance at a wavelength of 405 nm is 60% or more, it can be cured by irradiation with light containing a wavelength of 405 nm, and the cohesive force is increased to improve the foaming resistance after bonding. Can be obtained.
Further, since the photocurable pressure-sensitive adhesive sheet proposed by the present invention has a light transmittance of 80% or more at a wavelength of 410 nm, it has a sufficiently low yellowness (yellowness) required for bonding optical members that require transparency. The effect of achieving YI) can be obtained.

Next, an example of the embodiment of the present invention will be described. However, the present invention is not limited to such embodiments.

<< This adhesive sheet >>
The pressure-sensitive adhesive sheet (referred to as “the present pressure-sensitive adhesive sheet”) according to an example of the embodiment of the present invention is a photocurable pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer (Y) having predetermined characteristics.

This pressure-sensitive adhesive sheet is a photo-curable pressure-sensitive adhesive sheet that cures when irradiated with light. At this time, the present adhesive sheet may be cured (also referred to as "temporary curing") in a state where there is room for photocuring, or it has not been cured yet and has photocurability. It may be uncured (referred to as "uncured").
If the adhesive sheet is temporarily cured or uncured, the adhesive sheet can be photocured (also referred to as "main curing") after the adhesive sheet is attached to an adherend. As a result, the cohesive force can be increased and the adhesiveness can be enhanced.

The following preferred forms of the pressure-sensitive adhesive sheet have the above-mentioned properties of being temporarily cured or uncured and capable of being main-curable, that is, photocurability that is cured by irradiation with light having a wavelength of 405 nm. Examples of the pressure-sensitive adhesive sheet having the pressure-sensitive adhesive layer (Y) shown in (1) to (3) can be mentioned.

(1) The adhesive layer (Y) is temporarily cured so that the gel fraction is 60% or less, and contains the visible light initiator (c) described below to obtain the visible light initiator (c). This is an adhesive layer capable of main curing.
(2) The adhesive layer (Y) is temporarily cured by the hydrogen-extracted visible light initiator (c-2) of the visible light initiator (c) described below so that the gel content is 60% or less. This is an adhesive layer that can be finally cured by the visible light initiator (c-2).
(3) The adhesive layer (Y) retains its sheet shape in an uncured state, and by containing the visible light initiator (c) described below, this curing by the visible light initiator (c) is possible. Adhesive layer.

Examples of the method for forming the adhesive layer (Y) of the above (1) include a visible light initiator (c), a (meth) acrylic acid ester (co) polymer (a) having a functional group (i), and the above. A cross-linking agent (b) such as a compound having a functional group (ii) that reacts with the functional group (i) and, if necessary, a photopolymerizable compound having a carbon-carbon double bond (particularly a polyfunctional monomer). A method of heating or curing a composition (an example of the present resin composition described later) containing the silane coupling agent (d) and, if necessary, to form the adhesive layer (Y) can be mentioned. it can.
According to the method, the functional group (i) in the (meth) acrylic acid ester (co) polymer reacts with the functional group (ii) in the compound to form a chemical bond. It is cured (crosslinked) to form an adhesive layer (Y). By forming the adhesive layer (Y) in this way, the visible light initiator (c) can be present in the adhesive layer (Y) while still having activity.

Examples of the combination of the functional group (i) and the functional group (ii) include a carboxyl group and an epoxy group, a carboxyl group and an aziridyl group, a hydroxyl group and an isocyanate group, an amino group and an isocyanate group, and a carboxyl group and an isocyanate group. be able to. Among these, a combination of a hydroxyl group and an isocyanate group, an amino group and an isocyanate group, or a carboxyl group and an isocyanate group is particularly preferable. More specifically, it is particularly preferable that the (meth) acrylic acid ester copolymer (a) has a hydroxyl group (using the hydroxyl group-containing monomer described below) and the compound has an isocyanate group. Is.

Further, the compound having the functional group (ii) may further have a radically polymerizable functional group such as a (meth) acryloyl group. As a result, the light of the (meth) acrylic acid ester (co) polymer based on the radically polymerizable functional group, specifically, the (meth) acrylic acid ester copolymer having the active energy ray-crosslinkable structural site described below. The adhesive layer (Y) can be formed while maintaining the curability (crosslinking) property. More specifically, when the (meth) acrylic acid ester (co) polymer (a) has a hydroxyl group (using the hydroxyl group-containing monomer described below) and the compound has a (meth) acryloyl group. (2-Acryloyloxyethyl isocyanate, 2-methacryloyloxyethyl isocyanate, 1,1- (bisacryloyloxymethyl) ethyl isocyanate, etc.) are particularly preferable examples.
As described above, by utilizing the cross-linking reaction between the (meth) acrylic acid ester (co) polymers by the radically polymerizable functional group, the cohesive force after photocuring (cross-linking) without using the cross-linking agent (b). Is more preferable because it has advantages such as easy rise in efficiency and excellent reliability.

Regarding preferable forms of the acrylic acid ester (co) polymer (a), the cross-linking agent (b), the visible light initiator (c), and the silane coupling agent (d) regarding points other than the above. Will be described below.

As a method for forming the adhesive layer (Y) in (2) above, for example, as the visible light initiator (c), a method using the hydrogen abstraction type visible light initiator (c-2) described below can be mentioned. it can. The hydrogen-withdrawing-type disclosure agent can be used again as a visible light initiator because even if it is excited once, the unreacted initiator returns to the ground state. As described above, by using the hydrogen-extracting type visible light initiator, the visible light curing (crosslinking) property of the visible light initiator can be maintained even after the temporary curing by visible light irradiation.
The points other than the above and the preferable form of the visible light initiator (c-2) will be described below.

As a method for forming the adhesive layer (Y) in (3) above, for example, a method using the macromonomer described below as a monomer component constituting the (meth) acrylic acid ester copolymer (a) can be mentioned. .. More specifically, a method using a graft copolymer having a macromonomer as a branch component can be mentioned. By using such a macromonomer, it is possible to maintain a state in which the branch components are attracted to each other and physically crosslinked as a composition (an example of the present resin composition described later) at room temperature.
Therefore, the sheet shape can be maintained as it is uncured (crosslinked), and the adhesive layer (Y) containing the visible light initiator (c) can be formed.
The points other than the above and the preferable form of the graft copolymer having a macromonomer as a branch component will be described below.

This adhesive sheet is preferably used for bonding the resin member (X) described later.

The pressure-sensitive adhesive sheet may have a single-layer structure of the pressure-sensitive adhesive layer (Y) or a multi-layer structure of two or more layers having the pressure-sensitive adhesive layer (Y). Further, in the case of multiple layers, at least the outermost layer may be the adhesive layer (Y), and all the adhesive layers may be the adhesive layer (Y).

<Adhesive layer (Y)>
The adhesive layer (Y) preferably has all of the following properties (1) to (3).
(1) The gel fraction (referred to as "gel fraction before light irradiation X1") in the normal state, that is, the state before light irradiation is in the range of 0 to 60%.
(2) The light transmittance at a wavelength of 390 nm is 89% or less, and the light transmittance at a wavelength of 410 nm is 80% or more.
(3) It has photocurability that is cured by irradiation with light having a wavelength of 405 nm.

If the adhesive layer (Y) has a hot-melt property that softens or flows by heating, if there is a step such as unevenness on the adherend surface of the bonding member, it is easier to apply the adhesive to every corner of the step. It is preferable because it can be filled in and the step absorption property can be further enhanced.
From this point of view, the adhesive layer (Y) is preferably the adhesive layer (Y) of the above (3).

(Gel fraction)
The gel fraction (gel fraction X1 before light irradiation) of the adhesive layer (Y) is preferably in the range of 0 to 60%.
When the gel content of the adhesive layer (Y) is 60% or less, there are sufficiently many uncrosslinked components that can be cured by light irradiation (in a pre-cured state or an uncured state), and the adhesive layer (Y) is so flexible. Moreover, it is preferable from the viewpoint that "gel fraction after light irradiation X2-gel fraction before light irradiation X1" can be set to 10% or more at the time of main curing.
From this point of view, the gel fraction of the adhesive layer (Y) is preferably in the range of 0 to 60%, more preferably 55% or less, and more preferably 50% or less.

In order to adjust the gel fraction (gel fraction X1 before light irradiation) of the adhesive layer (Y) to the above range, the residual catalyst is sufficiently removed during the polymerization of the present resin composition and the processing of the adhesive sheet, which will be described later, or It is sufficient to prevent an unintended curing (crosslinking) reaction by heat, light, etc. from proceeding before the main curing by using a polymerization inhibitor or an antioxidant, or when provisionally curing is performed by light irradiation. The integrated amount of light emitted for temporary curing may be sufficiently reduced so that the amount of uncrosslinked components is sufficiently large. However, the method is not limited to this method.

Further, the adhesive layer (Y) preferably has photocurability that is cured by irradiation with light having a wavelength of 405 nm, and the degree of photocurability is, for example, from the outside of the resin member (X). When light with a wavelength of 405 nm is irradiated through (X), the difference in gel fraction is 10% or more, especially 15% or more, especially 20% or more, especially 30% or more, and among them, photocuring that increases by 50% or more. It is preferable to have sex.
"Irradiating light with a wavelength of 405 nm" means irradiating light having a photosensitivity that extends to a wavelength range of 320 to 470 nm with a wavelength of 405 nm as a photosensitive peak, which is measured using an ultraviolet photometer. Means.

Above all, when the adhesive layer (Y) is irradiated with light having ^{an integrated light amount of 3000 (mJ / cm 2} ) at a wavelength of 405 nm from the outside of the resin member (X), for example, through the resin member (X). , Difference between gel fraction before light irradiation (gel fraction before light irradiation X1) and gel fraction after light irradiation (referred to as "gel fraction after light irradiation X2") (gel fraction after light irradiation X2- It is preferable to have photocurability such that the gel fraction X1) before light irradiation is 10% or more.
Therefore, for example, when the gel fraction X1 before light irradiation is 40%, the gel fraction of the adhesive layer (Y) after irradiation with light having ^{an integrated light amount of 3000 (mJ / cm 2) at a wavelength of 405 nm (““} It is preferable to have photocurability such that the gel fraction X2 after light irradiation) is 50% or more.
When the gel fraction difference of the adhesive layer (Y) before and after photo-curing is 10% or more, high cohesive force is obtained even in a harsh high-temperature and high-humidity environment, and foaming reliability can be improved, which is preferable.
Therefore, the gel fraction difference of the adhesive layer (Y) before and after the light irradiation is preferably 10% or more, particularly 15% or more, particularly 20% or more, particularly 30% or more, and among them 50% or more. Is even more preferable.
In order to adjust the gel fraction difference of the adhesive layer (Y) before and after the light irradiation so as to be within the above range, absorption by the photoinitiator may be sufficient at a wavelength of 405 nm. However, the method is not limited to this method.

The "integrated light amount at a wavelength of 405 nm" is the total amount of irradiation energy received per unit area, and among the light emitted by a high-pressure mercury lamp or the like, the ultraviolet integrated light amount meter "UIT-250" (Ushio Electric Co., Ltd.) Refers to the total amount of light irradiation energy measured using the receiver (manufactured by Ushio Denki Co., Ltd.) and the receiver "UVD-C405" (manufactured by Ushio Denki Co., Ltd.). It refers to the integrated amount of light in the wavelength range according to (having light sensitivity that expands the base). More specifically, it refers to the integrated light intensity obtained in accordance with the method described in the examples.

(Light transmittance)
The adhesive layer (Y) preferably has a light transmittance of 89% or less at a wavelength of 390 nm and a light transmittance of 80% or more at a wavelength of 410 nm.
For pressure-sensitive adhesive formulations containing a light initiator that absorbs light in the ultraviolet to visible light region with a wavelength of around 400 nm, the light absorption of the light initiator is greater and the light transmittance at a wavelength of 390 nm derived from the absorption is lower. The photosensitivity is good and the curing is easy to proceed.
On the other hand, if the light transmittance at a wavelength of 410 nm is not higher than a certain level, the adhesive layer (Y) is colored yellow and it becomes difficult to use it for an optical member.

As a guideline above, when the light transmittance at a wavelength of 390 nm is 89% or less, the adhesive layer (Y) is preferable because sufficient visible light curability can be ensured, and the light transmittance at a wavelength of 410 nm is 80% or more. If this is the case, it is preferable because it is possible to achieve a sufficiently low yellowness (YI) required for bonding optical members that require transparency.
Therefore, the adhesive layer (Y) preferably has a light transmittance of 89% or less at a wavelength of 390 nm, and more preferably 88% or less.
Further, the light transmittance at a wavelength of 410 nm is preferably 80% or more, more preferably 85% or more, and more preferably 90% or more.
In order to make the light transmittance of the adhesive layer (Y) as described above, among the initiators that absorb visible light, the base of the absorption peak reaches 390 nm sufficiently, whereas the absorption peak reaches 410 nm. Those having a small absorption peak characteristic may be used. However, the method is not limited to this method.

(Storage modulus)
Storage modulus of the adhesive layer (Y) (G '), the temperature 25 ° C., at a frequency 1 Hz, is preferably less 0.9 × ¹⁰ 5 Pa.
By having such a viscoelastic property, the present adhesive sheet can obtain a particularly excellent step absorption property for filling a step such as unevenness of the adherend surface.
From this point of view, the storage elastic modulus (G') of the adhesive layer (Y) ^{is preferably 0.9 × 10 5} Pa or less, especially 0.8 × 10 ⁵ Pa or less, at a temperature of 25 ° C. and a frequency of 1 Hz. Is more preferable.

The adhesive layer (Y) also has a storage elastic modulus (G') of 0.7 at a temperature of 120 ° C. and a frequency of 1 Hz after irradiation with light having an integrated light intensity of 3000 (mJ / cm ^{2) at a wavelength of 405 nm.} It is preferably × 10 ⁴ Pa or more.
When the storage elastic modulus (G') of the adhesive layer (Y) after photocuring is within the above range, the resin member is subjected to a high temperature test, a high temperature and high humidity test, or the like when the laminate with the resin member (X) is subjected to a high temperature test, a high temperature and high humidity test, or the like. It is preferable in that the adhesive layer (Y) can be suppressed from foaming due to the outgas component from (X).
From this point of view, the storage elastic modulus (G') of the adhesive layer (Y) after photocuring ^{is preferably 0.7 × 10 4} Pa or more at a temperature of 120 ° C. and a frequency of 1 Hz, and more preferably 1.0 ×. It is more preferably 10 ⁴ Pa or more, and more preferably 2.0 × 10 ⁴ Pa or more.

By the way, in an image display device having a touch panel function, a glass sensor, a film sensor, and a polarizing plate glass (on-cell type or in-cell type with a built-in sensor) are used as touch sensors arranged on the back side of the front panel / adhesive layer. Etc. are used properly according to the module design, and the susceptibility to defects in the environmental test differs depending on the configuration of the sensor member.
As a result of experimental studies in the present invention, when the adhesive layer (Y) is used for bonding in the configuration of the resin member (X) / adhesive layer (Y) / glass sensor, the storage elastic modulus of the adhesive layer (Y) ( The preferable range of G') is as described above, but when the resin member (X) / adhesive layer (Y) / film sensor is used for bonding, the film sensor is usually thin with a thickness of 100 μm or less. Since the rigidity is low and the reliability improvement effect of the silane coupling agent is lower than the reliability improvement effect of the glass material, foaming is more likely to occur in the moist heat environment test than in the case of the glass sensor, and the storage elastic modulus is at a higher level. (G') is required.

Therefore, from this point of view, that is, the storage elastic modulus of the adhesive layer (Y) after photocuring when the adhesive layer (Y) is bonded and used in the configuration of the resin member (X) / adhesive layer (Y) / film sensor. The preferred range of the storage elastic modulus (G') of the adhesive layer (Y) when irradiated with light having a rate (G'), that is, an integrated light amount of 3000 (mJ / cm ^{2) at a wavelength of 405 nm is 2.} .0 × it is at ¹⁰ 4 Pa or more, more preferably among them 5.0 × ¹⁰ 4 Pa or more, and more preferably 8.0 × ¹⁰ 4 Pa or more among them.

(Composition of adhesive layer (Y))
The adhesive layer (Y) is a (meth) acrylic acid ester (co) polymer (a) and a visible light initiator (c), a cross-linking agent (b) if necessary, and a silane coupling agent if necessary. (D), it can be formed from a pressure-sensitive adhesive composition (referred to as "the present resin composition") further containing other materials, if necessary.

[(Meta) acrylic acid ester (co) polymer (a)]
The (meth) acrylic acid ester (co) polymer (a) is preferably photocurable.

In addition, "(meth) acrylic" means acrylic and methacrylic, "(meth) acryloyl" means acryloyl and methacryloyl, and "(meth) acrylate" means acrylate and methacrylate, respectively. Is. "(Co) polymer" means to include the polymer and the copolymer. Further, the "sheet" conceptually includes a sheet, a film, and a tape.

As the (meth) acrylic acid ester (co) polymer (a), for example, in addition to the homopolymer of alkyl (meth) acrylate, a copolymer obtained by polymerizing a monomer component copolymerizable with the homopolymer is used. Can be mentioned. For example, in addition to the homopolymer of alkyl (meth) acrylate, a copolymer obtained by polymerizing a monomer component copolymerizable therewith can be mentioned.

More specifically, as the (meth) acrylic acid ester (co) polymer (a), an alkyl (meth) acrylate and a monomer component copolymerizable therewith, for example, (a) a carboxyl group-containing monomer (hereinafter, "" (Also also referred to as "copolymerizable monomer A"), (b) hydroxyl group-containing monomer (hereinafter also referred to as "copolymerizable monomer B"), (c) amino group-containing monomer (hereinafter also referred to as "copolymerizable monomer C"). ), (D) Epoxy group-containing monomer (hereinafter, also referred to as "copolymerizable monomer D"), (e) Amid group-containing monomer (hereinafter, also referred to as "copolymerizable monomer E"), (f) Vinyl monomer (f) Hereinafter, it is also referred to as "copolymerizable monomer F"), (g) a (meth) acrylate monomer having 1 to 3 carbon atoms in the side chain (hereinafter, also referred to as "copolymerizable monomer G"), and (h) macromonomer. (Hereinafter, also referred to as "copolymerizable monomer H"), a copolymer with a monomer component containing any one or more monomers selected from the above can be mentioned.

As the alkyl (meth) acrylate, a linear or branched alkyl (meth) acrylate having 4 to 18 carbon atoms in the side chain is preferable.
Examples of the linear or branched alkyl (meth) acrylate having 4 to 18 carbon atoms in the side chain include n-butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, and t-butyl ( Meta) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, neopentyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, heptyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n- Octyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, t-butylcyclohexyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate , Lauryl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, isobornyl (meth) acrylate, 3,5,5- Examples thereof include trimethylcyclohexane (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate and the like. These may be used alone or in combination of two or more.
Among the above, any of butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate and isobornyl (meth) acrylate as the linear or branched alkyl (meth) acrylate having 4 to 18 carbon atoms. It is particularly preferable to contain one or more kinds.

Examples of the copolymerizable monomer A include (meth) acrylic acid, 2- (meth) acryloyloxyethyl hexahydrophthalic acid, 2- (meth) acryloyloxypropyl hexahydrophthalic acid, and 2- (meth) acryloyloxyethyl. Phthalic acid, 2- (meth) acryloyloxypropyl maleic acid, 2- (meth) acryloyloxyethyl maleic acid, 2- (meth) acryloyloxypropyl maleic acid, 2- (meth) acryloyloxyethyl succinic acid, 2-( Meta) Acryloyloxypropyl succinic acid, crotonic acid, fumaric acid, maleic acid, and itaconic acid can be mentioned. These may be one kind or a combination of two or more kinds.

Examples of the copolymerizable monomer B include hydroxyalkyls such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 2-hydroxybutyl (meth) acrylate. Meta) acrylates can be mentioned. These may be one kind or a combination of two or more kinds.

Examples of the copolymerizable monomer C include aminoalkyl (meth) acrylates such as aminomethyl (meth) acrylate, aminoethyl (meth) acrylate, aminopropyl (meth) acrylate, and aminoisopropyl (meth) acrylate, and N-alkylamino. Examples thereof include N, N-dialkylaminoalkyl (meth) acrylates such as alkyl (meth) acrylates, N, N-dimethylaminoethyl (meth) acrylates, and N, N-dimethylaminopropyl (meth) acrylates. These may be one kind or a combination of two or more kinds.

Examples of the copolymerizable monomer D include glycidyl (meth) acrylate, methyl glycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate glycidyl ether. .. These may be one kind or a combination of two or more kinds.

Examples of the copolymerizable monomer E include (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N-butyl (meth) acrylamide, N-methylol (meth) acrylamide, and N-methylolpropane (meth) acrylamide. Examples thereof include N-methoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, diacetone (meth) acrylamide, maleic acid amide, and maleimide. These may be one kind or a combination of two or more kinds.

Examples of the copolymerizable monomer F include compounds having a vinyl group in the molecule. Such compounds include (meth) acrylic acid alkyl esters having an alkyl group having 1 to 12 carbon atoms, functional monomers having a functional group such as a hydroxyl group, an amide group and an alkoxylalkyl group in the molecule, and functional monomers. Polyalkylene glycol di (meth) acrylates and vinyl ester monomers such as vinyl acetate, vinyl propionate and vinyl laurate and aromatic vinyl monomers such as styrene, chlorostyrene, chloromethylstyrene, α-methylstyrene and other substituted styrenes. Can be exemplified. These may be one kind or a combination of two or more kinds.
Among the above, it is preferable to select the alkyl (meth) acrylate and the copolymerizable monomer F other than the alkyl (meth) acrylate.

Examples of the copolymerizable monomer G include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, i-propyl (meth) acrylate and the like. These may be one kind or a combination of two or more kinds.
Among the above, it is preferable to select the alkyl (meth) acrylate and the copolymerizable monomer G other than the alkyl (meth) acrylate.

The macromonomer as the copolymerizable monomer H is a polymer monomer having a terminal functional group and a high molecular weight skeleton component, and is a side chain when it becomes a (meth) acrylic acid ester copolymer by polymerization. It is preferable that the monomer has 20 or more carbon atoms.

By using the copolymerizable monomer H, a macromonomer can be introduced as a branch component of the graft copolymer, and the (meth) acrylic acid ester copolymer can be used as the graft copolymer. For example, it can be a (meth) acrylic acid ester copolymer (a-1) composed of a graft copolymer having a macromonomer as a branch component.
Therefore, the characteristics of the main chain and the side chain of the graft copolymer can be changed by selecting and blending the copolymerizable monomer H and other monomers.

The skeleton component of the macromonomer is preferably composed of an acrylic acid ester polymer or a vinyl-based polymer. For example, those exemplified as the linear or branched alkyl (meth) acrylate having 4 to 18 carbon atoms in the side chain, the copolymerizable monomer A, the copolymerizable monomer B, the copolymerizable monomer G and the like are exemplified. These can be used alone or in combination of two or more.

Among them, the stem component of the (meth) acrylic acid ester copolymer (a-1) contains a hydrophobic (meth) acrylic acid ester and a hydrophilic (meth) acrylic acid ester as constituent units. preferable.

As the above-mentioned hydrophobic (meth) acrylic acid ester, an alkyl ester having no polar group (excluding methyl acrylate) is preferable, and for example, n-butyl (meth) acrylate, isobutyl (meth) acrylate, sec- Butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, neopentyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, heptyl (meth) acrylate, 2-Ethylhexyl acrylate, n-octyl acrylate, isooctyl acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, t-butylcyclohexyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) ) Acrylate, lauryl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, behenyl (meth) acrylate, isobornyl (meth) acrylate, cyclohexyl (meth) acrylate, dicyclopentenyloxy Ethyl (meth) acrylicate and methyl methacrylate can be mentioned.
Examples of the hydrophobic vinyl monomer include vinyl acetate, styrene, t-butyl styrene, α-methyl styrene, vinyl toluene, and alkyl vinyl monomer.

On the other hand, as the above-mentioned hydrophilic (meth) acrylate monomer, methyl acrylate or an ester having a polar group is preferable, for example, methyl acrylate, (meth) acrylic acid, tetrahydrofurfuryl (meth) acrylate, or hydroxyethyl (meth). Hydroxyl-containing (meth) acrylates such as acrylates, hydroxypropyl (meth) acrylates, hydroxybutyl (meth) acrylates, and glycerol (meth) acrylates, (meth) acrylic acid, 2- (meth) acryloyloxyethyl hexahydrophthalic acid, 2- (Meta) acryloyloxypropylhexahydrophthalic acid, 2- (meth) acryloyloxyethylphthalic acid, 2- (meth) acryloyloxypropylphthalic acid, 2- (meth) acryloyloxyethyl maleic acid, 2- (meth) ) Acryloyloxypropyl maleic acid, 2- (meth) acryloyloxyethyl succinic acid, 2- (meth) acryloyloxypropyl succinic acid, crotonic acid, fumaric acid, maleic acid, itaconic acid, monomethyl maleate, monomethyl itaconate, etc. Carboxyl group-containing monomer, acid anhydride group-containing monomer such as maleic anhydride and itaconic anhydride, glycidyl (meth) acrylate, glycidyl α-ethylacrylate, epoxy group such as 3,4-epoxybutyl (meth) acrylate. Examples thereof include a contained monomer, an alkoxypolyalkylene glycol (meth) acrylate such as methoxypolyethylene glycol (meth) acrylate, N, N-dimethylacrylamide, and hydroxyethylacrylamide.

The macromonomer as the copolymerizable monomer H preferably has a functional group such as a radically polymerizable group, a hydroxyl group, an isocyanate group, an epoxy group, a carboxyl group, an amino group, an amide group or a thiol group. ..
The macromonomer preferably has a radically polymerizable group that can be copolymerized with another monomer. One or two or more radically polymerizable groups may be contained, and one of them is particularly preferable.
When the macromonomer has a functional group, it may contain one or more functional groups, and one of them is particularly preferable.
Further, the radically polymerizable group and the functional group may be contained in either one or both. When both a radically polymerizable group and a functional group are contained, a functional group other than either a functional group added to a polymer unit composed of another monomer or a radically polymerizable group copolymerizing with another monomer or radical polymerization There may be two or more sex groups.

Examples of the terminal functional group of the macromonomer include a radical polymerization group such as a methacryloyl group, an acryloyl group and a vinyl group, as well as a hydroxyl group, an isocyanate group, an epoxy group, a carboxyl group, an amino group, an amide group and a thiol group. Functional groups can be mentioned.
Of these, those having a radically polymerizable group copolymerizable with other monomers are preferable. One or two or more radically polymerizable groups may be contained, and one of them is particularly preferable. Even when the macromonomer has a functional group, it may contain one or more functional groups, and one of them is particularly preferable.
Further, the radically polymerizable group and the functional group may be contained in either one or both. When both a radically polymerizable group and a functional group are contained, a functional group other than either a functional group to be added to a polymer unit composed of another monomer or a radically polymerizable group to be copolymerized with another monomer or radical polymerization There may be two or more sex groups.

The number average molecular weight of the macromonomer is preferably 500 to 20,000, particularly preferably 800 or more or 8000 or less, and particularly preferably 1000 or more or 7000 or less.

The glass transition temperature (Tg) of the macromonomer is preferably higher than the glass transition temperature of the copolymer component constituting the (meth) acrylic acid ester (co) polymer (a-1).
Specifically, the glass transition temperature (Tg) of the macromonomer affects the heating and melting temperature (hot melt temperature) of the adhesive sheet, and therefore is preferably 30 ° C. to 120 ° C., particularly 40 ° C. or higher or 110 ° C. More preferably, the temperature is 50 ° C. or higher, or 100 ° C. or lower.

If the macromonomer has such a glass transition temperature (Tg), by adjusting the molecular weight, excellent processability and storage stability can be maintained, and the temperature is adjusted so as to hot melt at around 50 ° C to 80 ° C. be able to.
The glass transition temperature of the macromonomer means the glass transition temperature of the macromonomer itself, and can be measured by a differential scanning calorimeter (DSC).

Further, in a room temperature state, it is possible to maintain a state in which the branch components are attracted to each other and physically cross-linked as an adhesive composition, and the physical cross-linking is released by heating to an appropriate temperature. In order to obtain fluidity, it is also preferable to adjust the molecular weight and content of the macromonomer.

From this point of view, the macromonomer is preferably contained in the (meth) acrylic acid ester copolymer (a) in a proportion of 5% by mass to 30% by mass, particularly 6% by mass or more or 25% by mass or less. Above all, it is more preferable to contain it in a proportion of 8% by mass or more or 20% by mass or less.
The number average molecular weight of the macromonomer is preferably 500,000 to 100,000, particularly preferably less than 8000, and more preferably 800 or more or less than 7,500, and more preferably 1,000 or more or less than 7,000.

The (meth) acrylic acid ester (co) polymer (a) preferably has an active energy ray-crosslinkable structural site.
The active energy ray-crosslinkable structure is, for example, a part of the (meth) acrylic acid ester copolymer (a) or the (meth) acrylic acid ester copolymer weight in the presence of the visible light initiator (c) described later. It is a structural part capable of forming a crosslinked structure by reacting with a hardening component other than the coalescence (a).

The active energy ray-crosslinkable structural site includes, for example, a structure having a radically polymerizable functional group having a carbon-carbon double bond such as a functional group having an unsaturated double bond such as a (meth) acryloyl group or a vinyl group. Can be mentioned.
Since the polymer chain of the (meth) acrylic acid ester (co) polymer (a) has an unsaturated double bond, the polymer chains can be directly polymerized even when the cross-linking agent is not contained. , The storage elasticity (G') can be raised to a high level.
When irradiating with active energy rays, any light source containing light having a wavelength of 405 nm may be used, and the visible light LED light source and high-pressure mercury are considered from the viewpoint of curing speed, availability of irradiation device, price, etc. You can use a lamp or the like.

In order to introduce a structure having a radically polymerizable functional group having a carbon-carbon double bond such as a functional group having an unsaturated double bond, for example, the above (meth) acrylic acid ester (co) polymer (a) can be introduced in advance. After copolymerizing a monomer having a functional group with, a carbon-carbon double such as a functional group capable of reacting with this functional group (for example, 2-isocyanatoethyl (meth) acrylate) and a monomer having an unsaturated double bond. The compound having a bond may be reacted while maintaining the curability of the carbon-carbon double bond.

Among them, the (meth) acrylic acid ester copolymer (a) contains a (meth) acrylic acid ester monomer having an active energy ray-crosslinkable structural site and having a linear alkyl group having 10 to 24 carbon atoms. It is preferably a (meth) acrylic acid ester (co) polymer (a-2) as a monomer component.
Examples of such (meth) acrylic acid ester (co) polymer (a-2) include decyl (meth) acrylate (alkyl group having 10 carbon atoms), lauryl (meth) acrylate (carbon number 12), and tridecyl (12 carbon atoms). Examples thereof include meta) acrylate (13 carbon atoms), hexadecyl (meth) acrylate (16 carbon atoms), stearyl (meth) acrylate (18 carbon atoms), and behenyl (meth) acrylate (22 carbon atoms). These may be used alone or in combination of two or more.

Further, among the linear (meth) acrylic acid alkyl ester monomers (a) having an alkyl group having 10 to 24 carbon atoms, the dielectric constant can be lowered and the glass transition temperature of the acrylic resin can be lowered. Alkyl methacrylates are preferably used, particularly preferably those having an alkyl group having 12 to 20 carbon atoms, and most preferably stearyl methacrylate, lauryl methacrylate, and tridecyl methacrylate.

The content of the (meth) acrylic acid alkyl ester monomer (a) having a linear alkyl group having 10 to 24 carbon atoms is 50 to 94% by weight, preferably 60 to 94% by weight, based on the total (co) polymerization component. It is 83% by weight, particularly preferably 70 to 80% by weight. Within the above range, there is no risk that the dielectric constant will increase or the thermal stability of the resin will decrease.

[Crosslinking agent (b)]
As the cross-linking agent (b), a cross-linking agent having at least a double bond cross-linking is preferable. For example, at least one crosslinkable functional group selected from (meth) acryloyl group, epoxy group, isocyanate group, carboxyl group, hydroxyl group, carbodiimide group, oxazoline group, aziridine group, vinyl group, amino group, imino group and amide group. The cross-linking agent having the above can be mentioned, and one kind or a combination of two or more kinds may be used.
In particular, by using two or more kinds of cross-linking agents in combination, a high storage elastic modulus (G') can be achieved even when the total compounding amount is the same as compared with the case where each is used alone.
Therefore, it is more preferable to use two or more kinds of the cross-linking agent (b) in combination.
Also included is an embodiment in which the cross-linking agent (b) is chemically bonded to the (meth) acrylic acid ester (co) polymer (a).

Of these, it is preferable to use a photopolymerizable compound having a carbon-carbon double bond, particularly a polyfunctional (meth) acrylate. Here, polyfunctional refers to one having two or more crosslinkable functional groups. If necessary, it may have three or more or four or more crosslinkable functional groups.
The crosslinkable functional group may be protected by a deprotectable protecting group.

Examples of the polyfunctional (meth) acrylate include 1,4-butanediol di (meth) acrylate, glycerindi (meth) acrylate, neopentyl glycol di (meth) acrylate, glycering ricidyl ether di (meth) acrylate, 1, 6-Hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, tricyclodecanedimethacrylate, tricyclodecanedimethanol di (meth) acrylate, bisphenol A polyethoxydi (meth) acrylate, bisphenol A poly Propoxydi (meth) acrylate, bisphenol F polyethoxydi (meth) acrylate, ethylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylpropantrioxyethyl (meth) acrylate, ε-caprolactone-modified tris (2) -Hydroxyethyl) isocyanurate tri (meth) acrylate, pentaerythritol tri (meth) acrylate, propoxylated pentaerythritol tri (meth) acrylate, ethoxylated pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, propoxylation Pentaerythritol tetra (meth) acrylate, ethoxylated pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, polyethylene glycol di (meth) acrylate, tris (acryloxyethyl) isocyanurate, dipentaerythritol hexa (meth) ) Acrylate, dipentaerythritol penta (meth) acrylate, tripentaerythritol hexa (meth) acrylate, tripentaerythritol penta (meth) acrylate, neopentyl glycol hydroxybivalate di (meth) acrylate, neopenglycol hydroxybivalate Ε-caprolactone adduct di (meth) acrylate, trimethyl propanetri (meth) acrylate, trimethyl propanepolyethoxytri (meth) acrylate, ditrimethylol propanetetra (meth) acrylate and other UV-curable polyfunctional (meth) acrylates. In addition to meta) acrylic monomers, polyfunctional (meth) acrylics such as polyester (meth) acrylate, epoxy (meth) acrylate, urethane (meth) acrylate, and polyether (meth) acrylate Oligomers can be mentioned. These may be used alone or in combination of two or more.

Among the above-mentioned polyfunctional (meth) acrylates, from the viewpoint of imparting high cohesive force, those having a short distance between cross-linking points and a dense cross-linking density in the formed cross-linking structure are preferable, and for example, alkylene oxide is not used. Denatured trifunctional or higher functional polyfunctional (meth) acrylates are preferred, with pentaerythritol trimethylolpropane (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and di. Selected from the group consisting of pentaerythritol penta (meth) acrylate, tripentaerythritol hexa (meth) acrylate, tripentaerythritol penta (meth) acrylate, trimethylolpropane tri (meth) acrylate, and trimethylolpropane tetra (meth) acrylate. Polyfunctional (meth) acrylate (b-1) is preferred.
The polyfunctional (meth) acrylate (b-1) may be used alone or in combination of two or more (as a mixture).

When the polyfunctional (meth) acrylate (b-1) is used as the cross-linking agent, the (meth) acrylic acid ester (a) contains a hydrophilic monomer as a polar component from the viewpoint of compatibility. It is preferably a copolymer of the monomer components contained.
Since the (meth) acrylic acid ester (a) contains a polar component, the compatibility with the polyfunctional (meth) acrylate (b-1) becomes good, it becomes easy to mix at the time of mixing, and it is long in an uncrosslinked state. Phase separation is less likely to occur during time storage, and there is no risk of the haze value increasing.

Specifically, the (meth) acrylic acid ester (co) polymer (a) is the above-mentioned alkyl (meth) acrylate, and the above-mentioned copolymerizable monomer is copolymerizable with the above-mentioned alkyl (meth) acrylate. A monomer component containing a hydrophilic monomer appropriately selected from A to G, particularly the above-mentioned hydrophilic (meth) acrylic acid ester, or at least a methyl (meth) acrylate selected from the copolymerizable monomer G. It is preferably a copolymer of.
Furthermore, the (meth) acrylic acid ester (co) polymer (a) contains at least methyl (meth) acrylate, and is the total of hydrophilic monomers (selected from copolymerizable monomers A to G). It is particularly preferable that the amount is a copolymer of a monomer component, which occupies 10 parts by mass or more in the whole (meth) acrylic acid ester (co) polymer (a).

The (meth) acrylic acid ester (co) polymer (a-1) is a linear or branched alkyl (meth) acrylate having 4 to 18 carbon atoms in the side chain described above as a skeleton component (stem component). And, as a copolymerizable monomer copolymerizable therewith, it is preferable that it is a copolymer of a monomer component containing the above-mentioned hydrophilic monomer.

The content of the cross-linking agent (b) is 0.5 to 50 parts by mass, particularly 1 part by mass or more or 40 parts by mass or less, based on 100 parts by mass of the (meth) acrylic acid ester (co) polymer (a). Among them, the ratio is preferably 5 parts by mass or more or 30 parts by mass or less.

[Visible light initiator (c)]
The visible light initiator (c) generates radicals by irradiation with visible light, light having wavelengths of at least 390 nm, 405 nm and 410 nm, for example, light in the wavelength range of 380 nm to 700 nm, and the (meth) acrylic acid ester (co-). ) A visible light initiator that serves as a starting point for the reaction of the polymer (a) is preferable.
However, the visible light initiator (c) may generate radicals only by irradiation with visible light, or may also generate radicals by irradiation with light in a wavelength region other than the visible light region. There may be.

The visible light initiator (c) preferably has an extinction coefficient of 10 mL / (g · cm) or more at a wavelength of 405 nm, particularly 15 mL / (g · cm) or more, and 25 mL / (g · cm) or more. It is more preferably cm) or more. When the absorption coefficient at a wavelength of 405 nm is 10 mL / (g · cm) or more, curing (crosslinking) by irradiation with visible light can sufficiently proceed.
On the other hand, the upper limit of the absorption coefficient at a wavelength of 405 nm ^{is preferably 1 × 10 4} mL / (g · cm) or less, and more preferably 1 × 10 ³ mL / (g · cm) or less.
It may be used in combination with a photoinitiator having an extinction coefficient of less than 10 mL / (g · cm) at a wavelength of 405 nm.

Photoinitiators are roughly classified into two types according to the radical generation mechanism. Cleavage-type photoinitiators that can generate radicals by cleaving the single bond of the photoinitiators themselves, photoinitiated initiators, and photoinitiators in the system. It is roughly classified into a hydrogen-extracted photoinitiator, which can form an excitation complex with a hydrogen donor and transfer the hydrogen of the hydrogen donor.

Of these, the cleavage-type photoinitiator decomposes to another compound when a radical is generated by light irradiation, and once excited, it loses its function as a reaction initiator. Therefore, it is preferable because it does not remain as an active species in the pressure-sensitive adhesive after the cross-linking reaction is completed and there is no possibility of causing unexpected photodegradation of the pressure-sensitive adhesive.
Further, regarding the coloring peculiar to the photoinitiator, conventionally, when the cleaved visible light initiator (c-1) which cures by irradiating the pressure-sensitive adhesive with visible light is added, there is a risk of coloring. Therefore, as the visible light initiator (c), it is preferable to appropriately select an initiator (c) that does not absorb the reactive decomposition product in the visible light region and decolorizes.
On the other hand, the hydrogen-extracted photoinitiator can not only maintain its function as a reaction initiator even if it is irradiated with light multiple times, but also initiates a cleavage-type light initiator during a radical generation reaction due to irradiation with active energy rays such as ultraviolet rays. Since it does not generate decomposition products such as agents, it is less likely to become a volatile component after the reaction is completed, which is useful in that damage to the adherend can be reduced.
Therefore, a hydrogen abstraction type visible light polymerization initiator (c-2) that is excited by visible light to initiate polymerization is particularly preferable.

Examples of the cleavage-type visible light initiator (c-1) include 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxycyclohexylphenylketone, and 2-hydroxy-2-methyl-1-. Phenyl-Propane-1-one, 1- (4- (2-hydroxyethoxy) phenyl) -2-hydroxy-2-methyl-1-propane-1-one, 2-Hirodoxy-1- [4- {4- {4- (2-Hydroxy-2-methyl-propionyl) benzyl} phenyl] -2-methyl-propan-1-one, oligo (2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) phenyl) propanone ), Methyl phenylglycoxylate, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butane-1-one, 2-methyl-1- [4- (methylthio) phenyl] -2- Morphorinopropan-1-one, 2- (dimethylamino) -2-[(4-methylphenyl) methyl) -1- [4- (4-morpholinyl) phenyl] -1-butanone, bis (2,4) Examples thereof include 6-trimethylbenzoyl) -phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, (2,4,6-trimethylbenzoyl) ethoxyphenylphosphine oxide, and derivatives thereof.
Among these, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, (2,4,6), which are decomposed after the reaction and are discolored. Acylphosphine oxide-based photoinitiators such as −trimethylbenzoyl) ethoxyphenylphosphine oxide and bis (2,6-dimethoxybenzoyl) 2,4,4-trimethylpentylphosphine oxide are preferred.

Examples of the hydrogen abstraction type visible light initiator (c-2) include bis (2-phenyl-2-oxoacetic acid) oxybisethylene, phenylglycilic acid methyl ester, and oxy-phenyl-acetylid 2- [. A mixture of 2-oxo-2-phenyl-acetoxy-ethoxy] ethyl ester and oxy-phenyl-acetylid 2- [2-hydroxy-ethoxy] ethyl ester, thioxanthone, 2-chlorothioxanthone, 3-methylthioxanthone, 2, Examples thereof include 4-dimethylthioxanthone, anthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butyl anthraquinone, 2-aminoanthraquinone, phenylquinone and derivatives thereof.
Among these, phenylglycilic acid methyl ester, oxy-phenyl-acetylid 2- [2-oxo-2-phenyl-acetoxy-ethoxy] ethyl ester and oxy-phenyl-acetylid 2- [2-hydroxy- It is preferably any one or two selected from the group consisting of a mixture of ethoxy] ethyl esters.

The visible light initiator (c) is not limited to the substances listed above. Any one of the visible light initiators (c) listed above or a derivative thereof may be used, or two or more of them may be used in combination.
Further, in addition to the visible light initiator (c), one that generates radicals only by irradiation with other light rays such as ultraviolet rays may be mixed.

The content of the visible light initiator (c) is not particularly limited. 0.1 to 10 parts by mass, especially 0.5 parts by mass or more or 5 parts by mass or less, among 100 parts by mass of the (meth) acrylic acid ester (co) polymer (a) in the adhesive layer (Y). It is preferably contained in a proportion of 1 part by mass or more or 3 parts by mass or less.
By setting the content of the visible light initiator (c) in the above range, it is possible to obtain an appropriate reaction sensitivity to visible light.

[Silane Coupling Agent (d)]
The silane coupling agent (d) can improve the adhesiveness, especially the adhesive force to the glass material.
Examples of the silane coupling agent include compounds having a hydrolyzable functional group such as an alkoxy group as well as an unsaturated group such as a vinyl group, an acryloxy group and a methacryloxy group, an amino group and an epoxy group. ..
Specific examples of the silane coupling agent include N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane, N- (β-aminoethyl) -γ-aminopropylmethyldimethoxysilane, and γ-aminopropyltriethoxy. Examples thereof include silane, γ-glycidoxypropyltrimethoxysilane, and γ-methacryloxypropyltrimethoxysilane.
Among them, in the adhesive layer (Y), γ-glycidoxypropyltrimethoxysilane or γ-methacryloxypropyltrimethoxysilane is preferable from the viewpoint of good adhesiveness and less discoloration such as yellowing. Can be used.
The silane coupling agent may be used alone or in combination of two or more.

The content of the silane coupling agent (d) is preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the adhesive layer (Y), and more than 0.2 parts by mass or 3.0 parts by mass or less. Is more preferable.
As with the silane coupling agent, a coupling agent such as an organic titanate compound can be effectively used.

[Other materials]
Ingredients other than the above contained in the present resin composition forming the adhesive layer (Y) include, for example, a light stabilizer, an ultraviolet absorber, a metal inactivating agent, a metal corrosion inhibitor, an antiaging agent, and an antistatic agent. Various additives such as agents, hygroscopic agents, foaming agents, defoaming agents, inorganic particles, viscosity modifiers, antistatic resins, photosensitizers, fluorescent agents, reaction catalysts (tertiary amine compounds, quaternary ammonium compounds) Compounds, tin laurate compounds, etc.) can be mentioned.
In addition, other known components to be blended in a normal pressure-sensitive adhesive composition may be appropriately contained.
Moreover, you may use 2 or more types of each component in combination.

Among the above, it is particularly preferable that the present resin composition forming the adhesive layer (Y) contains an ultraviolet absorber. As described above, since the adhesive layer (Y) has photocurability that is cured by irradiation with light having a wavelength of 405 nm, the photocuring is not hindered even if it contains an ultraviolet absorber. Therefore, by containing the ultraviolet absorber, it is possible to have excellent ultraviolet ray blocking property without impairing the properties of the pressure-sensitive adhesive sheet.

Examples of the ultraviolet absorber include benzotriazole-based ultraviolet absorbers, benzophenone-based ultraviolet absorbers, triazine-based ultraviolet absorbers, and the like. The ultraviolet absorbers may be used alone or in combination of two or more.
Among them, the above-mentioned ultraviolet absorber is particularly preferably a triazine-based ultraviolet absorber from the viewpoint of transparency, ultraviolet absorption and compatibility.

[Preferable compositional aspect of the present resin composition]
As an example of the preferred resin composition for forming the adhesive layer (Y), a (meth) acrylic acid ester (co) polymer (a), the above-mentioned cross-linking agent (b), a visible light initiator (c), and the like. If necessary, a composition containing a silane coupling agent can be mentioned.
Among these, as the visible light initiator (c), it is preferable to use the visible light initiator (c) having an absorption coefficient of 10 mL / (g · cm) or more at a wavelength of 405 nm, and the visible light initiator (c). ), It is particularly preferable to use the cleavage type visible light initiator (c-1) and / or the hydrogen abstraction type visible light initiator (c-2).

Among them, the (meth) acrylic acid ester (co) polymer (a) has a carboxyl group and an epoxy group, a carboxyl group and an aziridyl group, a hydroxyl group and an isocyanate group, an amino group and an isocyanate group, and a carboxyl group and an isocyanate group. It is preferable that a chemical bond is formed by a combination of any of the functional groups selected from the above.
Further, the (meth) acrylic acid ester (co) polymer (a) contains the above-mentioned linear or branched alkyl (meth) acrylate having 4 to 18 carbon atoms in the side chain and the above-mentioned hydrophilic (meth) acrylate. Is preferably a copolymer containing the above as a copolymerization component.
Furthermore, it is preferable that the cross-linking agent (b) is the above-mentioned polyfunctional (meth) acrylate (b-1).

As an example of the preferable present resin composition forming the adhesive layer (Y), the above (meth) acrylic acid ester copolymer (a-1) composed of a graft copolymer having a macromonomer as a branch component and the above cross-linking. Examples thereof include a composition containing the agent (b), the visible light initiator (c), and, if necessary, a silane coupling agent.
Among these, as the visible light initiator (c), it is preferable to use the visible light initiator (c) having an absorption coefficient of 10 mL / (g · cm) or more at a wavelength of 405 nm, and the visible light initiator (c). ), It is particularly preferable to use the cleavage type visible light initiator (c-1) and / or the hydrogen abstraction type visible light initiator (c-2).

Among them, the above-mentioned (meth) acrylic acid ester (co) polymer (a-1) is a linear or branched alkyl (meth) acrylate having the above-mentioned side chain having 4 to 18 carbon atoms as a skeleton component (stem component). And the above-mentioned hydrophilic (meth) acrylate are preferably a copolymer containing the above-mentioned hydrophilic (meth) acrylate as a copolymerization component.
Further, it is preferable that the cross-linking agent (b) is the above-mentioned polyfunctional (meth) acrylate (b-1).

As a further example of the preferred resin composition forming the adhesive layer (Y), the above (meth) acrylic composed of a graft copolymer comprising a macromonomer as a branch component and having an active energy ray-crosslinkable structural site. Examples thereof include a composition containing an acid ester copolymer (a-1), the above-mentioned cross-linking agent (b), the above-mentioned visible light initiator (c), and, if necessary, a silane coupling agent.
Among these, as the visible light initiator (c), it is preferable to use the visible light initiator (c) having an absorption coefficient of 10 mL / (g · cm) or more at a wavelength of 405 nm, and the visible light initiator (c). ), It is particularly preferable to use the cleavage type visible light initiator (c-1) and / or the hydrogen abstraction type visible light initiator (c-2).

Among them, the above-mentioned (meth) acrylic acid ester (co) polymer (a-1) is a linear or branched alkyl (meth) acrylate having the above-mentioned side chain having 4 to 18 carbon atoms as a skeleton component (stem component). And the above-mentioned hydrophilic (meth) acrylate are preferably a copolymer containing the above-mentioned hydrophilic (meth) acrylate as a copolymerization component.
Further, it is preferable that the cross-linking agent (b) is the above-mentioned polyfunctional (meth) acrylate (b-1).

If the pressure-sensitive adhesive layer (Y) is formed using the present resin composition having the above composition, the pressure-sensitive adhesive layer (Y) using the (meth) acrylic acid ester copolymer (a) or (a-1) as the base resin. ) Can exhibit self-adhesiveness while maintaining the sheet shape at room temperature, and can be filled with the adhesive to every corner of the step on the adherend surface of the bonding member. Moreover, the visible light initiator (c) can be photocured by irradiation with visible light, and the cohesive force can be enhanced by photocuring to enhance the foaming reliability.
Further, by blending a silane coupling agent, the adhesiveness, particularly the adhesiveness to the glass material can be further enhanced.
Further, the adhesive layer (Y) using the (meth) acrylic acid ester copolymer (a-1) as a base resin has a hot-melt property that melts or flows when heated in addition to the above, and thus has higher step absorption. Can have.

As a further example of the preferred resin composition for forming the adhesive layer (Y), a (meth) acrylic acid having an active energy ray-crosslinkable structural site and having a linear alkyl group having 10 to 24 carbon atoms. A (meth) acrylic acid ester (co) polymer (a-2) of a monomer component containing an ester monomer, the cross-linking agent (b), the visible light initiator (c), and a silane cup, if necessary. Examples thereof include a composition containing a ring agent. Among these, as the visible light initiator (c), it is preferable to use the visible light initiator (c) having an absorption coefficient of 10 mL / (g · cm) or more at a wavelength of 405 nm, and the visible light initiator (c). ), It is particularly preferable to use the cleavage type visible light initiator (c-1) and / or the hydrogen abstraction type visible light initiator (c-2).

By using the present resin composition having the above composition, it is possible to form a temporarily cured or uncured adhesive layer (Y) in a state where there is room for photocuring, and then once or once. It can be photocured by irradiating with visible light two or more times. Therefore, for example, after the present adhesive sheet is attached to an adherend, the present adhesive sheet can be photocured (“main curing”) by irradiation with visible light, and the cohesive force is enhanced by the main curing to improve foaming reliability. Can be enhanced.
In particular, even when a (meth) acrylic acid ester (co) polymer, which has high fluidity at room temperature and has difficulty in storage, is subjected to a step of improving storage stability by temporary curing, visible light curing after bonding is performed. Curing can proceed by a post-step.
Further, by blending a silane coupling agent, the adhesiveness, particularly the adhesiveness to the glass material can be further enhanced.

(Laminated structure)
As described above, when the pressure-sensitive adhesive layer (Y) is laminated, it is preferable that the pressure-sensitive adhesive layer (Y) using the present resin composition is the outermost layer, the front and back layers, from the viewpoint of foam resistance.
At this time, the thickness of the adhesive layer (Y) as the front and back layers is preferably 15 μm or more, and more preferably 20 μm or more. When the thickness of the adhesive layer (Y) is 15 μm or more, it is preferable in the reliability test that there is little possibility that problems such as foaming due to the outgas pressure generated from the adherend member are reduced.

Further, from the viewpoint of providing storage stability, it may be preferable to further provide another layer having a viscosity higher than that of the adhesive layer (Y).
That is, the adhesive layer (Y) formed by using the graft copolymer provided with the macromonomer is in an uncrosslinked state before photo-curing, and when a polyfunctional (meth) acrylate monomer is used, the polyfunctional (meth) acrylate monomer is used. Due to the action of the meta) acrylate monomer component, the adhesive layer (Y) before photo-curing may become a layer having a relatively low viscosity.
Therefore, in such a case, it is preferable to laminate another layer (Z) having a viscosity higher than that of the adhesive layer (Y) on the adhesive layer (Y).
For example, a multi-layer structure including three layers of an adhesive layer (Y) / layer (Z) / adhesive layer (Y) can have excellent storage stability.
From the viewpoint of such storage stability, the viscosity of the other layer (Z) is preferably 1 to 10 kPa · s in the temperature range of 70 ° C. to 100 ° C., preferably 1.5 to 5 kPa · s. More preferably.
The viscosity is a value measured according to the method described in Examples.

Further, when the pressure-sensitive adhesive sheet has a multi-layer structure as described above, the glass transition temperature (Tg) of the pressure-sensitive adhesive sheet after irradiation with 405 nm light is less than 20 ° C. from the viewpoint of further providing shock absorption. It is preferably less than 10 ° C. and more preferably less than 10 ° C.
When the present adhesive sheet has such a relatively low Tg, the low temperature adhesive property (low temperature peel strength, etc.) can be improved and the impact resistance can be absorbed.
Therefore, from the viewpoint of shock absorption, the Tg of the other layer laminated with the adhesive layer (Y) after irradiation with 405 nm light is less than 15 ° C., particularly less than 10 ° C., particularly less than 5 ° C. Especially preferable.
The Tg is a value measured at the peak temperature of Tan δ of dynamic viscoelasticity, and is a value measured in detail according to the method described in Examples.

<Adhesive sheet with release film>
The present adhesive sheet may also be an adhesive sheet with a release film.
For example, a single-layer or multi-layer sheet-like adhesive layer may be formed on the release film to obtain an adhesive sheet with a release film.

As a material of such a release film, a known release film can be appropriately used.
As the material of the release film, for example, a film such as a polyester film, a polyolefin film, a polycarbonate film, a polystyrene film, an acrylic film, a triacetyl cellulose film, or a fluororesin film is coated with a silicone resin and subjected to a release treatment. A release paper or the like can be appropriately selected and used.

When the release films are laminated on both sides of the pressure-sensitive adhesive sheet, one release film may have the same laminated structure or material as the other release film, or may have a different laminated structure or material. Good.
Further, the thickness may be the same or different.
Further, release films having different peeling forces and release films having different thicknesses can be laminated on both sides of the pressure-sensitive adhesive sheet.

The release film preferably has a light transmittance of 40% or less at a wavelength of 410 nm or less.
By laminating a release film having a light transmittance of 40% or less at a wavelength of 410 nm or less on at least one surface of the adhesive sheet, it is possible to effectively prevent photopolymerization from proceeding due to irradiation with visible light. Can be done.
From this point of view, the release film laminated on one or both surfaces of the pressure-sensitive adhesive sheet preferably has a light transmittance of 40% or less at a wavelength of 410 nm or less, particularly 30% or less, and 20% or less among them. Is more preferable.

Here, as a release film having a light transmittance of 40% or less at a wavelength of 410 nm or less, that is, a film having a function of partially blocking the transmission of visible light and ultraviolet light, for example, polyester-based film, polypropylene-based film, and the like. A laminated film having an ultraviolet absorbing layer formed by applying a fine adhesive resin having removability to one surface of a polyethylene-based cast film or a stretched film and applying a paint containing an ultraviolet absorber to the other surface. Can be mentioned.
In addition, one surface of a polypropylene-based or polyethylene-based cast film or a stretched film may be coated with a slightly adhesive resin having a removability and containing an ultraviolet absorber.
In addition, a cast film or a stretched film made of a polyester-based, polypropylene-based, or polyethylene-based resin containing an ultraviolet absorber may be coated with a slightly adhesive resin having removability.
In addition, a multi-layer cast film or stretched film formed by molding a layer made of a resin containing no ultraviolet absorber on one or both sides of a layer made of a polyester-based, polypropylene-based, or polyethylene-based resin containing an ultraviolet absorber. One surface coated with a slightly adhesive resin having removability can be mentioned.
Further, a paint containing an ultraviolet absorber is applied to one surface of a cast film or a stretched film made of polyester-based, polypropylene-based, or polyethylene-based resin to provide an ultraviolet absorbing layer, and the film is peeled off again on the ultraviolet absorbing layer. Examples thereof include those coated with a slightly adhesive resin having a property.
Further, a paint containing an ultraviolet absorber is applied to one surface of a cast film or a stretched film made of polyester-based, polypropylene-based, or polyethylene-based resin to provide an ultraviolet absorbing layer, and the other surface has fine removability. Examples thereof include those coated with an adhesive resin.
Furthermore, the other surface of the resin film made of polyester-based, polypropylene-based, or polyethylene-based resin coated with a slightly adhesive resin having removability on one surface and the separately prepared resin film contain an ultraviolet absorber. Examples thereof include those laminated via an adhesive layer or an adhesive layer.
The film may have other layers, such as an antistatic layer, a hard coat layer, and an anchor layer, if necessary.

The thickness of the release film is not particularly limited. Among them, for example, from the viewpoint of workability and handleability, it is preferably 25 μm to 500 μm, and more preferably 38 μm or more or 250 μm or less, and more preferably 50 μm or more or 200 μm or less.

The adhesive sheet employs, for example, a method of directly extruding the resin composition or a method of molding by injecting the resin composition into a mold without using an adherend or a release film as described above. You can also do it.
Further, the present adhesive sheet can be obtained by directly filling the resin composition between the constituent members for an image display device, which is an adherend.

<Manufacturing method of this adhesive sheet>
An example of a method for manufacturing the present adhesive sheet will be described.
First, a (meth) acrylic acid ester (co) polymer (a) and a visible light initiator (c), further a cross-linking agent (b) if necessary, and a further silane coupling agent (d) if necessary. The present resin composition may be prepared by further mixing a predetermined amount of each of the other materials according to the above.
The mixing method thereof is not particularly limited, and the mixing order of each component is not particularly limited. Further, a heat treatment step may be added during the production of the composition. In this case, it is desirable to mix each component of the present resin composition in advance and then perform the heat treatment.
Further, a masterbatch obtained by concentrating various mixed components may be used.

The apparatus for mixing is not particularly limited, and for example, a universal kneader, a planetary mixer, a Banbury mixer, a kneader, a gate mixer, a pressurized kneader, a triple roll, and a double roll can be used. If necessary, it may be mixed with a solvent.
Further, the present resin composition can be used as a solvent-free system containing no solvent. By using it as a solvent-free system, it is possible to have an advantage that the solvent does not remain and the heat resistance and the light resistance are improved.
From this point of view, the resin composition is preferably in a form containing the (meth) acrylic acid ester (co) polymer (a), the cross-linking agent (b) and the visible light initiator (c).

The present adhesive sheet can be produced by applying (coating) the present resin composition prepared as described above on a base sheet or a release sheet.
Further, for example, in the laminated structure of the present adhesive sheet, the present resin composition is applied (coated) on a base sheet or a release sheet to form a first layer, and the first layer is formed. A method of repeatedly applying (coating) the present resin composition on the layer to form the second layer, or forming the first and second layers in the same manner as described above. After that, it is produced by a method of laminating the coated (coated) surfaces to each other, or a method of forming the first layer and the second layer at the same time by multi-layer coating or coextrusion molding of the present resin composition. can do.

As the above coating (coating) method, any general coating method can be adopted without particular limitation. For example, roll coating, die coating, gravure coating, comma coating, screen printing and the like can be mentioned.

Then, if necessary, the pressure-sensitive adhesive layer made of the present resin composition is irradiated with light to temporarily cure the pressure-sensitive adhesive layer (Y), leaving room for photo-curing, and gel of the pressure-sensitive adhesive layer (Y). The fraction may be 0 to 60%. However, it is not always necessary to irradiate the adhesive layer (Y) with light to temporarily cure the adhesive layer (Y), for example, the adhesive layer (Y) may be temporarily cured by heat or curing, or it remains uncured. May be good.

<Use of this adhesive sheet>
As described above, the present adhesive sheet can be suitably used for bonding the resin member (X).
For example, the resin member (X) and the image display panel (P) are bonded to each other via the present adhesive sheet to form a photocurable pressure-sensitive adhesive sheet laminate, and the integrated light amount at 405 nm from the resin member (X) side. By irradiating the adhesive sheet with light having a value of 3000 (mJ / cm ² ) through the resin member (X), the adhesive layer (Y) is photocured, and the gel fraction difference before and after photocuring is 10% or more. The image display panel laminate can be manufactured by aggregating the images.

(Resin member (X))
The resin member (X) preferably has a light transmittance of 10% or less at 365 nm and a light transmittance of 60% or more at 405 nm.

If the light transmittance at 365 nm is 10% or less and the light transmittance at 405 nm is 60% or more, the transmission of ultraviolet rays is sufficiently blocked (cut), and the resin member (X) itself and its back side (visual recognition) are sufficiently blocked. Suppressing the optical deterioration of an optical member (for example, an optical film such as a polarizing film or a retardation film) located on the side surface) and reducing the yellowness (YI) to the level required for the optical member. Can be done.
Examples of such a resin member (X) include a resin member (X) whose main component is a resin material and which is adjusted to have the light transmittance by using an ultraviolet absorber.

Examples of the resin material include a material containing a polycarbonate resin or an acrylic resin as a main component resin.
At this time, the "main component resin" means the resin having the largest mass content among the resins constituting the resin member (X).

(Image display panel (P))
The image display panel (P) is composed of, for example, another optical film such as a polarizing film or other retardation film, a liquid crystal material, and a backlight system (usually, the adherend surface of the composition or the adhesive article to the image display panel is It is an optical film), and there are STN method, VA method, IPS method, etc. depending on the control method of the liquid crystal material, but any method may be used.
Further, the image display panel may be an in-cell type having a touch panel function built in the TFT-LCD, or an on-cell type having a touch panel function built in between a polarizing plate and a glass substrate provided with a color filter.

In the present adhesive sheet, the adhesive layer (Y) in the state where the target object is attached as described above, that is, the adhesive layer (Y) after light (book) curing is the present resin composition from the viewpoint of foaming reliability. It is particularly preferable to have a crosslinked structure made of a material.
In particular, as described above, the adhesive layer (Y) uses a (meth) acrylic acid ester copolymer having an active energy ray-curable site, or a (meth) acrylic acid ester having a functional group (i) (meth). Co) It is provided with a chemical bond between the polymer (a) and a compound having a functional group (ii) that reacts with the functional group (i), or an alkylene oxide-unmodified trifunctional or higher functional (meth). It is particularly preferable that the polymer is formed using an acrylate and has a crosslinked structure resulting from these.

<< Explanation of words and phrases >>
In the present invention, the term "film" shall include the "sheet", and the term "sheet" shall include the "film".
Further, when the term "panel" is used, such as an image display panel or a protective panel, it includes a plate body, a sheet, and a film.

In the present invention, when "X to Y" (X, Y are arbitrary numbers) is described, it means "X or more and Y or less" and "preferably larger than X" or "preferably Y". It also includes the meaning of "smaller".
Further, when "X or more" (X is an arbitrary number) is described, it includes the meaning of "preferably larger than X" and is described as "Y or less" (Y is an arbitrary number) unless otherwise specified. In this case, unless otherwise specified, it also includes the meaning of "preferably smaller than Y".

The following will be described in more detail with reference to Examples. However, the present invention is not limited to the examples described below.

<Example / Comparative example>
The materials used in Examples and Comparative Examples will be described.

[Example 1]
(Photo-curable adhesive sheet Y)
As a (meth) acrylic acid ester (co) polymer, 13.5 parts by mass of a macromonomer (number average molecular weight 3000) having an isobornyl methacrylate: methyl methacrylate = 1: 1 and a terminal functional group having a methacryloyl group, An acrylic graft copolymer (mass average molecular weight: 160,000) prepared by randomly copolymerizing 43.7 parts by mass of lauryl acrylate, 40 parts by mass of 2-ethylhexyl acrylate, and 2.8 parts by mass of acrylamide was prepared.
A mixture containing 90 g of propoxylated pentaerythritol triacrylate (NK ester ATM-4PL, manufactured by Shin-Nakamura Chemical Co., Ltd.) as a cross-linking agent and a cleavage-type visible light initiator as a visible light initiator with respect to 1 kg of this acrylic graft copolymer. There are 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, oligo (2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) propanone), 2,4,6-trimethyl. 15 g of a mixture of benzophenone and 4-methylbenzophenone (Ester KTO46 manufactured by Lamberti) was added and uniformly mixed to obtain a photocurable composition.
Next, the photocurable composition is formed into a sheet having a thickness of 150 μm on a polyethylene terephthalate film (manufactured by Mitsubishi resin, Diafoil MRV, thickness 100 μm) whose surface has been peeled off. A polyethylene terephthalate film (manufactured by Mitsubishi Resin, Diafoil MRQ, thickness 75 μm) whose surface was peeled off was coated to prepare a photocurable pressure-sensitive adhesive sheet Y1 with a release film.
The photocurable pressure-sensitive adhesive sheet Y1 was a photo-curable pressure-sensitive adhesive sheet that was cured by irradiating with light.

(Resin member X)
As the resin member (X), it is a polycarbonate-based resin plate (manufactured by Mitsubishi Gas Chemical Company, MR58) containing an ultraviolet absorber, and has a thickness of 1.0 mm (used in the bonding configuration P) and 1.5 mm (pasted). (Used in the combined configuration Q and the bonded configuration R) was used.
All the thicknesses had a light transmittance of 0% at 365 nm and a light transmittance of 83% at 405 nm.

(Photo-curable adhesive sheet laminate)
The release film on one surface of the photocurable pressure-sensitive adhesive sheet Y1 with a release film is peeled off, and the resin member (X) / photo-curable pressure-sensitive adhesive sheet Y1 is roll-bonded to one surface of the polycarbonate plate (resin member X). A photocurable pressure-sensitive adhesive sheet laminate (also referred to as "X / Y1 laminate") was obtained.

[Example 2]
Except for changing the type of cross-linking agent for the photocurable adhesive sheet Y to pentaerythritol triacrylate (NK ester ATMM3 manufactured by Shin-Nakamura Chemical Co., Ltd.) and changing the number of copies to 70 g per 1 kg of acrylic graft copolymer. A photocurable pressure-sensitive adhesive sheet Y2 and an X / Y2 laminate were obtained in the same manner as in Example 1.
The photocurable pressure-sensitive adhesive sheet Y2 was a photo-curable pressure-sensitive adhesive sheet that was cured by irradiating with light.

[Example 3]
The composition of the (meth) acrylic copolymer of the photocurable pressure-sensitive adhesive sheet Y is a macromonomer (number average molecular weight 3000) having an isobornyl methacrylate: methyl methacrylate = 1: 1 and a terminal functional group having a methacryloyl group. A hydroxy group formed by randomly copolymerizing 12.7 parts by mass, lauryl acrylate by 41.1 parts by mass, 2-ethylhexyl acrylate by 37.6 parts by mass, acrylamide by 2.6 parts by mass, and 4-hydroxybutyl acrylate by 6 parts by mass. Active energy of carbon-carbon double bond obtained by addition reaction of 6.5 parts by mass of 2-isocyanatoethyl methacrylate to 100 parts by mass of the contained acrylic graft copolymer (mass average molecular weight: 160,000). A photocurable pressure-sensitive adhesive sheet Y3 and an X / Y3 laminate were obtained in the same manner as in Example 1 except that the copolymer was changed to a (meth) acrylic copolymer having a linearly crosslinkable structural site. The photocurable pressure-sensitive adhesive sheet Y3 was a photo-curable pressure-sensitive adhesive sheet that was cured by irradiating with light.

[Example 4]
As a photocurable pressure-sensitive adhesive sheet, a hydrogen-extracted visible light initiator, phenylglioxylic acid methyl ester (Irgacure MBF manufactured by BASF) was used as a visible light initiator, and the integrated light amount at 405 nm was 100 (in advance). Photocurable pressure-sensitive adhesive sheets Y4 and X / Y4 laminates were obtained in the same manner as in Example 1 except that the ones that were primarily cured (crosslinked) by irradiating light so as to have mJ / cm ^{2) were used.} It was.
The photocurable pressure-sensitive adhesive sheet Y4 was a photo-curable pressure-sensitive adhesive sheet that was cured by irradiating with light.

[Example 5]
As a (meth) acrylic acid ester (co) polymer, 13.5 parts by mass of a macromonomer (number average molecular weight 3000) having an isobornyl methacrylate: methyl methacrylate = 1: 1 and a terminal functional group having a methacryloyl group, A cross-linking agent using an acrylic graft copolymer (mass average molecular weight: 260,000) obtained by randomly copolymerizing 73.7 parts by mass of 2-ethylhexyl acrylate, 2.8 parts by mass of acrylamide and 10 parts by mass of methyl acrylate. In the same manner as in Example 1, except that the type of pentaerythritol triacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., NK ester ATMM3L) was changed and the number of parts to be blended was changed to 70 g per 1 kg of the acrylic graft copolymer. A curable pressure-sensitive adhesive sheet Y5 and an X / Y5 laminate were obtained.
The photocurable pressure-sensitive adhesive sheet Y5 was a photo-curable pressure-sensitive adhesive sheet that was cured by irradiating with light.

[Example 6]
A photocurable pressure-sensitive adhesive sheet Y6 and an X / Y6 laminate were obtained in the same manner as in Example 5 except that the amount of the cross-linking agent blended was changed to 120 g with respect to 1 kg of the acrylic graft copolymer.
The photocurable pressure-sensitive adhesive sheet Y6 was a photo-curable pressure-sensitive adhesive sheet that was cured by irradiating with light.

[Example 7]
The types of cross-linking agents are pentaerythritol triacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., NK ester ATMM3L) and dipentaerythritol tetraacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., NK ester A9570W) for 1 kg of acrylic graft copolymer. A photocurable pressure-sensitive adhesive sheet Y7 and an X / Y7 laminate were obtained in the same manner as in Example 5 except that 90 g and 30 g were used in combination.
The photocurable pressure-sensitive adhesive sheet Y7 was a photo-curable pressure-sensitive adhesive sheet that was cured by irradiating with light.

[Example 8]
The type of cross-linking agent is 120 g each of pentaerythritol triacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., NK ester ATMM3L) and dipentaerythritol tetraacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., NK ester A9570W) per 1 kg of acrylic graft copolymer. , 40 g of the photocurable adhesive sheet Y8 and the X / Y8 laminate were obtained in the same manner as in Example 5 except that they were used in combination.
The photocurable pressure-sensitive adhesive sheet Y8 was a photo-curable pressure-sensitive adhesive sheet that was cured by irradiating with light.

[Example 9]
As a (meth) acrylic copolymer, 13.5 parts by mass of a macromonomer (number average molecular weight 3,000) having an isobornyl methacrylate: methyl methacrylate = 1: 1 and a terminal functional group having a methacryloyl group, 2 -As a cross-linking agent for 1 kg of an acrylic graft copolymer (mass average molecular weight: 260,000) obtained by randomly copolymerizing 73.7 parts by mass of ethylhexyl acrylate, 2.8 parts by mass of acrylamide and 10 parts by mass of methyl acrylate. Pentaerythritol triacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., NK ester ATMM3L) and dipentaerythritol tetraacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., NK ester A9570W) were used in combination in an amount of 75 g and 25 g, respectively, and cleaved as a visible light initiator. 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, oligo (2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) propanone, a mixture containing a type visible light initiator ), A mixture of 2,4,6-trimethylbenzophenone and 4-methylbenzophenone (Ester KTO46 manufactured by Lamberti) was added, and 2 g of 3-glycidoxypropyltrimethoxysilane (manufactured by Shinetsu Silicon Co., Ltd.) was added as a silane coupling agent. KBM403) was uniformly mixed to obtain a photocurable composition.
Next, the photocurable composition is formed into a sheet having a thickness of 25 μm on a polyethylene terephthalate film (manufactured by Mitsubishi Chemical Corporation, Diafoil MRV, thickness 100 μm) whose surface has been peeled off. , A polyethylene terephthalate film (manufactured by Mitsubishi Chemical Corporation, Diafoil MRQ, thickness 75 μm) whose surface has been peeled off was coated to prepare an adhesive sheet Y9a for front and back layers with a release film.

As the (meth) acrylic copolymer, pentaerythritol triacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., NK ester ATMM3L) was used as a cross-linking agent for 1 kg of the same acrylic graft copolymer used in the adhesive sheet Y9a for the front and back layers. ) 30 g, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, oligo (2-hydroxy-2-methyl-1- (4-), which is a mixture containing a cleaved visible light initiator as a visible light initiator. 15 g of a mixture of (1-methylvinyl) phenyl) propanone), 2,4,6-trimethylbenzophenone and 4-methylbenzophenone (Ester KTO46 manufactured by Lamberti) was added and uniformly mixed to obtain a photocurable composition. It was.
Next, the photocurable composition is formed into a sheet having a thickness of 100 μm on a polyethylene terephthalate film (manufactured by Mitsubishi Chemical Corporation, Diafoil MRV, thickness 100 μm) whose surface has been peeled off. , A polyethylene terephthalate film (manufactured by Mitsubishi Chemical Corporation, Diafoil MRQ, thickness 75 μm) whose surface has been peeled off was coated to prepare an adhesive sheet Y9b for an intermediate layer with a release film.

The PET films on both sides of the intermediate layer adhesive sheet Y9b are sequentially peeled off and removed, and the adhesive surfaces of the two front and back layer adhesive sheets Y9a are sequentially bonded to both surfaces of the intermediate layer adhesive sheet Y9b (front and back layers). Adhesive sheet Y9 for 2 types and 3 layers (total thickness 150 μm) composed of adhesive sheet Y9a for intermediate layer / adhesive sheet Y9b for intermediate layer / (adhesive sheet Y9a for front and back layers) and Example 1 In the same manner, an X / Y9 laminate was obtained.

[Example 10]
The (meth) acrylic copolymer used in the adhesive sheet Y9b for the intermediate layer is a macromonomer having an isobornyl methacrylate: methyl methacrylate = 1: 1 and a terminal functional group having a methacryloyl group (number average molecular weight 3,). 000) is 13.5 parts by mass, lauryl acrylate is 43.7 parts by mass, 2-ethylhexyl acrylate is 40 parts by mass, and acrylamide is 2.8 parts by mass at random copolymerization of an acrylic graft copolymer (mass average). (Adhesive sheet Y9a for front and back layers) / (Adhesive sheet Y10b for front and back layers) / (For front and back layers) in the same manner as in Example 9 except that the pressure-sensitive adhesive sheet Y10b for the intermediate layer was formed by changing the molecular weight to 160,000). Photocurable pressure-sensitive adhesive sheets Y10 and X / Y10 laminates (total thickness 150 μm) of two types and three layers made of the pressure-sensitive adhesive sheet Y9a) were obtained.
The photocurable pressure-sensitive adhesive sheet Y10 was a photo-curable pressure-sensitive adhesive sheet that was cured by irradiating with light.

[Comparative Example 1]
Examples except that a mixture of 2,4,6-trimethylbenzophenone and 4-methylbenzophenone (Esasure TZT, manufactured by Lamberti), which is a hydrogen-extracting initiator as a photoinitiator, was used as the photocurable pressure-sensitive adhesive sheet. A photocurable pressure-sensitive adhesive sheet Y11 and an X / Y11 laminate were obtained in the same manner as in 1.

[Comparative Example 2]
As a photocurable pressure-sensitive adhesive sheet, 1- [4- (4-benzoylphenyl sulfanyl) phenyl] -2-methyl-2- (4-methylphenylsulfonyl) propane-, which is a hydrogen-drawing initiator as a photoinitiator Photocurable pressure-sensitive adhesive sheets Y12 and X / Y12 laminates were obtained in the same manner as in Example 1 except that 1-on (Esacure1001M manufactured by Lamberti) was used.

[Comparative Example 3]
Example 1 and Example 1 except that 2,4-diethylthioxanthone (manufactured by Nippon Kayaku Co., Ltd., DETX-S), which is a visible light absorbing hydrogen extraction type initiator, was used as the photocurable pressure-sensitive adhesive sheet. Similarly, a photocurable pressure-sensitive adhesive sheet Y13 and an X / Y13 laminate were obtained.

[Comparative Example 4]
A photocurable pressure-sensitive adhesive sheet Y14 and an X / Y14 laminate in the same manner as in Example 1 except that a commercially available non-curable transparent pressure-sensitive adhesive sheet for optics, which does not have photocurability, was used as the photo-curable pressure-sensitive adhesive sheet. Got

<Evaluation>
The evaluation method displayed in the present specification will be described.

(1) Dynamic storage elastic modulus (G')
For each of the 150 μm photocurable pressure-sensitive adhesive sheets Y1 to Y14 (without release film) obtained in Examples and Comparative Examples, eight sheets were stacked to make 1200 μm, and the dynamic viscoelasticity measuring device rheometer (Eiko Seiki Co., Ltd.) The measurement was carried out under the conditions of an adhesive jig: Φ25 mm parallel plate, strain: 0.5%, frequency 1 Hz, and heating rate: 3 ° C./min.

(2) Spectral Transmittance With respect to the resin member (X), the spectral transmittance (% T) at a wavelength of 300 nm to 800 nm was measured using a spectrophotometer (UV2000 manufactured by Shimadzu Corporation). Such spectral transmittance was defined as light transmittance.

(3) Gel fraction Each of the photocurable pressure-sensitive adhesive sheets Y1 to Y14 (without a release film) obtained in Examples and Comparative Examples was bag-shaped with a SUS mesh (# 200) whose mass (X) was measured in advance. After wrapping the bag in a bag, folding the mouth of the bag and closing it, measuring the mass (Y) of this bag, immersing it in 100 ml of ethyl acetate and storing it in a dark place at 23 ° C. for 24 hours, then taking out the package and taking it out at 70 ° C. After heating for 5 hours to evaporate the adhering ethyl acetate, the mass (Z) of the dried package was measured, and the obtained mass was substituted into the following formula to obtain the gel fraction X1.
Gel fraction (%) = [(ZX) / (YX)] x 100

Further, for each of the X / Y1 to Y14 laminates obtained in Examples and Comparative Examples, the integrated light amount at 405 nm was 3000 (mJ / cm ² ) from the resin member (X) side using a high-pressure mercury lamp. After irradiating with light so as to be, a sample was taken from the adhesive layer portion on the resin member (X) side surface of the photocurable adhesive sheet, and the gel fraction X2 was determined by the same method as described above. Then, X2-X1 was calculated.

(4) Step absorption 58 mm x 110 mm x 0.8 mm thick glass peripheral edge (3 mm on the long side, 15 mm on the short side) is printed with a thickness of 22 to 24 μm, and the central recess is 52 mm x 80 mm. A glass plate with a printing step was prepared.
For each of the photocurable adhesive sheets Y1 to Y14 with the release film obtained in Examples and Comparative Examples, one of the release films was peeled off, and the entire surface of the soda lime glass (54 mm × 82 mm × thickness 0.5 mm) was covered. After laminating the rolls, the other remaining release film is peeled off, and vacuum crimping is performed using a vacuum press so that the adhesive sheet is applied to the frame-shaped printing step of the glass plate with the printing step (temperature 25 ° C., press). A pressure of 0.13 MPa) was applied to prepare an evaluation sample.
After the evaluation sample was autoclaved under the conditions of 60 ° C., 0.2 MPa and 20 min, pass / fail was judged according to the following evaluation criteria.
○ (good): No microbubbles are seen around the step × (poor): Microbubbles are seen around the step

(5) Yellowness (YI)
For each of the X / Y1 to Y14 laminates obtained in Examples and Comparative Examples, the integrated light intensity at 405 nm is 3000 (mJ / cm ² ) from the resin member (X) side using a high-pressure mercury lamp. Irradiated with light.
The integrated light intensity at 405 nm is the integrated light intensity of the resin member (X) using the ultraviolet integrated light intensity meter "UIT-250" (manufactured by Ushio Electric Co., Ltd.) and the receiver "UVD-C405" (manufactured by Ushio Electric Co., Ltd.). The integrated amount of light transmitted through the resin member (X) and irradiated to the photocurable adhesive sheets (Y1 to Y14) measured by installing a photometric meter on the surface opposite to the surface irradiated by the high-pressure mercury lamp. is there.
After that, the yellowness (YI) of the X / Y1 to Y14 laminate was measured based on JIS K7103 using a spectrophotometer (Suga Test Instruments Co., Ltd.) "SC-T", and the yellowness (YI) of the X / Y1 to Y14 laminate was measured according to the following evaluation criteria. The pass / fail was judged.
○ (good): YI is less than 2 × (poor): YI is 2 or more

(6) UV resistance (ΔYI)
With respect to the X / Y1 to Y14 laminates obtained in Examples and Comparative Examples, light was emitted from the resin member (X) side using a high-pressure mercury lamp so that the integrated light amount at 405 nm was 3000 (mJ / cm ² ). Irradiated.
The integrated light intensity at 405 nm is the integrated light intensity of the resin member (X) using the ultraviolet integrated light intensity meter "UIT-250" (manufactured by Ushio Electric Co., Ltd.) and the receiver "UVD-C405" (manufactured by Ushio Electric Co., Ltd.). The integrated amount of light transmitted through the resin member (X) and irradiated to the photocurable adhesive sheets (Y1 to Y14) measured by installing a photometric meter on the surface opposite to the surface irradiated by the high-pressure mercury lamp. is there.
After that, an irradiation test at a distance of 20 cm and 72 hr was carried out using a UVB fluorescent lamp (G15T8E manufactured by Sankyo Electric Co., Ltd., irradiance of 70 μW / cm ^2).
Pass / fail was determined by the following evaluation criteria from the amount of change ΔYI in the yellowness (YI) of the X / Y1 to Y14 laminates before and after irradiation.
○ (good): ΔYI is less than 0.2 × (poor): ΔYI is 0.2 or more

(7) Foaming reliability For each of the X / Y laminates obtained in Examples and Comparative Examples, the other release film remaining on the Y surface side was peeled off, and the following three types of members were placed on the exposed surface by a hand roller. The foaming resistance at the time of sticking was evaluated.
Further, the X / Y laminate was cut to the size of each member and used.
Specific bonding configurations include X / Y laminate / member P (bonding configuration P), X / Y laminate / member Q (bonding configuration Q), and X / Y laminate / member R (bonding configuration). There are three types of R).
Member P: Soda lime glass 54 mm x 82 mm x thickness 0.55 mm
Member Q: Soda lime glass 100 mm x 180 mm x thickness 0.55 mm
Member R PET film 100 mm x 180 mm x thickness 100 μm

Further, the member P (bonding configuration P) is subjected to an autocrepe treatment under the conditions of a temperature of 60 ° C., an atmospheric pressure of 0.2 MPa, and 30 minutes for finish bonding, and the members Q and R (bonding configuration Q) are subjected to finish bonding. And R) were autoclaved under the conditions of a temperature of 80 ° C., an atmospheric pressure of 0.2 MPa, and 30 minutes for finish sticking.

After the finish sticking, a high-pressure mercury lamp is used to irradiate the resin member (X) side with light so that the integrated light amount at 405 nm is 3000 (mJ / cm ² ) to prepare a foaming reliability evaluation sample. did.
The evaluation sample was exposed to an environment of 85 ° C. and 85% R.H. for 24 hours, and "○ (good)" was obtained when no appearance defect such as foaming or peeling was observed, and "○ (good)" was observed when foaming or peeling was observed. It was judged as "x (poor)".
Further, the bonding configuration P or Q (single-sided glass member) and the bonding configuration R (double-sided resin member) in which no appearance defect such as foaming or peeling is observed is designated as "◎ (very good)", and the bonding configuration P is defined as "◎ (very good)". , Q and R with no appearance defects such as foaming or peeling are marked as "○ (good)", and those with foaming or peeling in all of the bonded configurations P, Q and R are marked with "○ (good)". × (poor) ”was comprehensively judged.

(8) Haze after long-term storage (indicator of compatibility with cross-linking agent)
For each of the photocurable adhesive sheets Y obtained in Examples and Comparative Examples, two months or more have passed since the sheets were prepared, and then the release film of the adhesive sheet Y was peeled off to expose two adhesive surfaces on both sides. It was bonded so as to be sandwiched between soda lime glass (thickness 0.55 mm), irradiated with light using a high-pressure mercury lamp so that the integrated light amount at 405 nm was 3000 (mJ / cm ² ), and then the haze value was measured. ..
The haze value was measured according to JIS K7136 using a haze meter (NDH5000, manufactured by Nippon Denshoku Kogyo Co., Ltd.).
A haze value of less than 0.5 is "○ (good)", a haze value of 0.5 or more and less than 1.0 is "△ (satisfactory)", and a haze value of 1.0 or more is "x". (Poor) ”.

(9) Tg after photo-curing
For each of the 150 μm photocurable pressure-sensitive adhesive sheets Y1 to Y14 (without release film) obtained in Examples and Comparative Examples, light was previously provided so that the integrated light amount at 405 nm was 3000 (mJ / cm ² ). After irradiating, eight photocurable adhesive sheets Y1 to Y14 were stacked to make 1200 μm, and an adhesive jig: Φ25 mm parallel was used using a dynamic viscoelasticity measuring device rheometer (“MARS” manufactured by Eiko Seiki Co., Ltd.). The measurement was performed under the conditions of a plate, strain: 0.5%, frequency 1 Hz, and heating rate: 3 ° C./min, and the temperature at which the obtained Tan δ value peaked was measured as Tg.

(10) Viscosity For each of the 150 μm photocurable pressure-sensitive adhesive sheets Y1 to Y14 (without release film) obtained in Examples and Comparative Examples, eight sheets were stacked to make 1200 μm, and a dynamic viscoelasticity measuring device rheometer ( Using "MARS" manufactured by Eiko Seiki Co., Ltd.), adhesive jig: Φ25 mm parallel plate, strain: 0.5%, frequency 1 Hz, temperature rise rate: 3 ° C / min, at 70 ° C and 100 ° C, respectively. The complex viscosity of the pressure-sensitive adhesive sheet before photocuring was measured.

(11) Storability A photocurable pressure-sensitive adhesive sheet Y1 to 14 cut into 50 mm × 50 mm squares was sandwiched between two 100 mm × 100 mm square PET films having a thickness of 100 μm to prepare a laminated body at 23 ° C. and 50%. After leaving it for 300 hours in the above environment, it was visually observed whether the adhesive squeezed out from the laminate.
By visually observing the prepared laminate, the adhesive that protruded as a whole was "x (poor)", the adhesive that protruded only at the corners was "△ (satisfactory)", and the adhesive did not protrude. The thing was judged as "○ (good)".

<Discussion>
The photocurable pressure-sensitive adhesive sheet laminates (X / Y1 to Y10 laminates) of the resin member (X) / photo-curable pressure-sensitive adhesive sheets (Y1 to Y10) of Examples 1 to 10 have wavelengths from the resin member (X) side. When the photocurable adhesive sheets Y1 to Y10 are irradiated with light so that the integrated light amount at 405 nm is 3000 (mJ / cm ² ), the photocurable adhesive sheets Y1 to Y10 may be sufficiently cured so that the difference in gel fraction increases by 10% or more. can, dynamic storage modulus (G ') 120 ° C., at 1 Hz, because it holds the hot cohesion than 0.7 × ¹⁰ 4 Pa, a good anti-foaming reliability was obtained. In particular, good foam resistance and reliability were obtained in a test assuming that the touch sensor was a glass sensor.
Among them, in Examples 3, 7, 9, and 10, since the dynamic storage elastic modulus (G') maintained a high-temperature cohesive force of ^{2.0 × 10 4 Pa or more at 120 ° C. and 1 Hz, the touch sensor was used.} Good foam resistance and reliability were obtained even when placed in a test assuming the case of a film sensor.

Further, in Example 8, good foam resistance was obtained in the test assuming that the touch sensor was a film sensor, but the glass peeled off in the test assuming that the touch sensor was a glass sensor. Has occurred. It is considered that this is because the dynamic storage elastic modulus (G') becomes too high at 120 ° C. and 1 Hz, and the tack and adhesive performance deteriorate.
In Example 2, since the content of the hydrophilic monomer constituting the (meth) acrylic acid ester (co) polymer (a) was 10 parts by mass or less, phase separation proceeded during long-term storage. The haze after long-term storage was “Δ (satisfactory)”.
It is considered that the step absorption is good in all of Examples 1 to 10, and the cover member having a printing step can be put into practical use depending on the type of the touch sensor.

Further, in Examples 4, 9 and 10, since the viscosity (70 ° C.) was as high as 1.5 kPa · s or more, no glue squeezed out even after long-term storage, and the storage property was excellent.

In Comparative Examples 1 and 2, the light transmittance (%) of the photocurable pressure-sensitive adhesive sheets Y11 and Y12 at a wavelength of 390 nm was as high as 90% or more, and the integrated light amount at a wavelength of 405 nm was 3000 (from the resin member (X) side). When the light is irradiated so as to be mJ / cm ² ), the adhesion layer (Y) cannot be sufficiently cured because the excitation and curing (crosslinking) reactions due to the light absorption of the light initiator are not sufficiently advanced, and the adhesive layer (Y) cannot be sufficiently cured. Bubbles were generated during the reliability test.

In Comparative Example 3, the light transmittance (%) of the photocurable adhesive sheet Y13 at a wavelength of 410 nm is as low as 70%, and the light absorption in the visible light region is large, so that the yellowness (YI) of the adhesive layer (Y) is high. It got higher.

Comparative Example 4, the gel fraction of the photocuring adhesive sheet Y14 88%, dynamic storage modulus (G ') (25 ℃) because of its high and 1.1 × ¹⁰ 5 Pa, step absorbability is poor, Bubbles were generated.

Claims (27)

It has a resin member (X), an image display panel (P), and a photocurable adhesive sheet.
The resin member (X) has a light transmittance of 10% or less at a wavelength of 365 nm and a light transmittance of 60% or more at a wavelength of 405 nm.
The photocurable pressure-sensitive adhesive sheet is an image display panel laminate having an pressure-sensitive adhesive layer (Y) having all of the following properties (1) to (4).
(1) The gel fraction (referred to as "gel fraction before light irradiation X1") is in the range of 0 to 50%.
(2) The light transmittance at a wavelength of 390 nm is 89% or less, and the light transmittance at a wavelength of 410 nm is 80% or more.
(3) It has photocurability that is cured by irradiation with light having a wavelength of 405 nm.
(4) The photocurability in (3) above is 20% as a difference in gel fraction when light having a wavelength of 405 nm is irradiated from the outside of the resin member (X) through the resin member (X). It is a photocurable material that increases beyond that. It has a resin member (X), an image display panel (P), and a photocurable adhesive sheet.
The resin member (X) has a light transmittance of 10% or less at a wavelength of 365 nm and a light transmittance of 60% or more at a wavelength of 405 nm.
The photocurable pressure-sensitive adhesive sheet is an image display panel laminate having an pressure-sensitive adhesive layer (Y) having all the following characteristics (1) to (3), (5) and (6).
(1) The gel fraction (referred to as "gel fraction before light irradiation X1") is in the range of 0 to 50%.
(2) The light transmittance at a wavelength of 390 nm is 89% or less, and the light transmittance at a wavelength of 410 nm is 80% or more.
(3) It has photocurability that is cured by irradiation with light having a wavelength of 405 nm.
(5) The photocurability in (3) above is 15% or more as a difference in gel fraction when light having a wavelength of 405 nm is irradiated from the outside of the resin member (X) through the resin member (X). Increased photocurability.
(6) It is formed from a pressure-sensitive adhesive composition containing a (meth) acrylic acid ester (co) polymer, and does not contain acrylic acid as a copolymerization component of the (co) polymer. It has a resin member (X), an image display panel (P), and a photocurable adhesive sheet.
The resin member (X) has a light transmittance of 10% or less at a wavelength of 365 nm and a light transmittance of 60% or more at a wavelength of 405 nm.
The photocurable pressure-sensitive adhesive sheet is an image display panel laminate having an pressure-sensitive adhesive layer (Y) having all the following characteristics (1) to (3), (5) and (7).
(1) The gel fraction (referred to as "gel fraction before light irradiation X1") is in the range of 0 to 50%.
(2) The light transmittance at a wavelength of 390 nm is 89% or less, and the light transmittance at a wavelength of 410 nm is 80% or more.
(3) It has photocurability that is cured by irradiation with light having a wavelength of 405 nm.
(5) The photocurability in (3) above is 15% or more as a difference in gel fraction when light having a wavelength of 405 nm is irradiated from the outside of the resin member (X) through the resin member (X). Increased photocurability .
(7) It is formed from a pressure-sensitive adhesive composition containing a (meth) acrylic acid ester (co) polymer, and the pressure-sensitive adhesive composition does not contain an epoxy-based cross-linking agent. It has a resin member (X), an image display panel (P), and a photocurable adhesive sheet.
The resin member (X) has a light transmittance of 10% or less at a wavelength of 365 nm and a light transmittance of 60% or more at a wavelength of 405 nm.
The photocurable pressure-sensitive adhesive sheet is an image display panel laminate having an pressure-sensitive adhesive layer (Y) having all of the following properties (1) to (3) and (8).
(1) The gel fraction (referred to as "gel fraction before light irradiation X1") is in the range of 0 to 60%.
(2) The light transmittance at a wavelength of 390 nm is 89% or less, and the light transmittance at a wavelength of 410 nm is 80% or more.
(3) It has photocurability that is cured by irradiation with light having a wavelength of 405 nm.
(8) Temporarily cured by light irradiation. The photocurability in (3) above is increased by 10% or more as a difference in gel fraction when light having a wavelength of 405 nm is irradiated from the outside of the resin member (X) through the resin member (X). The image display panel laminate according to claim 4 , characterized in that it is of a sex property. The photocurability in (3) above is increased by 30% or more as a difference in gel fraction when light having a wavelength of 405 nm is irradiated from the outside of the resin member (X) through the resin member (X). The image display panel laminate according to any one of claims 1 to 5 , which is a property. ^{When light with an integrated light amount of 3000 (mJ / cm 2} ) at a wavelength of 405 nm is irradiated from the outside of the resin member (X) through the resin member (X), the gel fraction (light irradiation) before light irradiation is performed. The difference between the pre-gel fraction X1) and the gel fraction after light irradiation (referred to as "gel fraction after light irradiation X2") (gel fraction after light irradiation X2-gel fraction before light irradiation X1) is 10%. The image display panel laminate according to claim 4 or 5 , wherein the image display panel laminate has the above-mentioned photocurability. ^{When light with an integrated light amount of 3000 (mJ / cm 2} ) at a wavelength of 405 nm is irradiated from the outside of the resin member (X) through the resin member (X), the gel fraction (light irradiation) before light irradiation is performed. The difference between the pre-gel fraction X1) and the gel fraction after light irradiation (referred to as "gel fraction after light irradiation X2") (gel fraction after light irradiation X2-gel fraction before light irradiation X1) is 30%. The image display panel laminate according to any one of claims 1 to 7 , wherein the image display panel laminate has the above-mentioned photocurability. The image display panel laminate according to any one of claims 4, 5 and 7 , wherein the adhesive layer (Y) has a gel fraction of 0 to 50 %. The gel fraction of the adhesive layer (Y) is greater than 0 and 50% or less, and the adhesive layer (Y) is temporarily cured by light irradiation, according to claims 1 to 3, 6 and 8 . The image display panel laminate according to any one. The image display panel laminate according to any one of claims 1 to 10 , wherein the adhesive layer (Y) contains a (meth) acrylic acid ester (co) polymer and a visible light initiator. The (meth) acrylic acid ester (co) polymer is human Dorokishiru groups and isocyanate groups, and a chemical binding by a combination of any of the functional groups selected from among amino groups and isocyanate groups is formed The image display panel laminate according to claim 11.
The image display panel laminate according to claim 11 or 12 , wherein the (meth) acrylic acid ester (co) polymer is a graft copolymer having a macromonomer as a branch component. The (meth) acrylic acid ester (co) polymer contains a linear or branched alkyl (meth) acrylate having 4 to 18 carbon atoms in the side chain and a hydrophilic (meth) acrylate as copolymerization components. The image display panel laminate according to any one of claims 11 to 13 , which is a copolymer. The image display panel laminate according to any one of claims 11 to 14 , wherein the (meth) acrylic acid ester (co) polymer has an active energy ray-crosslinkable structural site. The image display panel laminate according to any one of claims 11 to 15 , wherein the visible light initiator has an extinction coefficient of 10 mL / (g · cm) or more at a wavelength of 405 nm. The image display panel laminate according to any one of claims 11 to 16 , wherein the visible light initiator is a hydrogen-extracting visible light initiator. The hydrogen abstraction type visible light initiator is phenylglycilic acid methyl ester, oxy-phenyl-acetylid 2- [2-oxo-2-phenyl-acetoxy-ethoxy] ethyl ester and oxy-phenyl-acetylid. The image display panel laminate according to claim 17 , which is any one or two selected from the group consisting of a mixture of 2- [2-hydroxy-ethoxy] ethyl esters. The image display panel laminate according to any one of claims 1 to 18 , wherein the adhesive layer (Y) contains a silane coupling agent. The image display panel laminate according to any one of claims 1 to 19 , wherein the adhesive layer (Y) contains a cross-linking agent or is formed by using a cross-linking agent. The image display panel laminate according to claim 20 , wherein the cross-linking agent is chemically bonded to the (meth) acrylic acid ester (co) polymer. The image display panel laminate according to claim 20 or 21 , wherein the cross-linking agent is a polyfunctional (meth) acrylate. The image display panel laminate according to any one of claims 20 to 22 , wherein the cross-linking agent is an alkylene oxide-unmodified trifunctional or higher functional (meth) acrylate. Temperature 25 ° C., at a frequency 1 Hz, the storage modulus of the adhesive layer (Y) (G ') is, the image display panel laminate according to any one of claims 1 to 23 is 0.9 × ¹⁰ 5 Pa or less .. The storage elastic modulus (G') of the adhesive layer (Y) after irradiation with light having an integrated light amount of 3000 (mJ / cm ^{2) at a wavelength of 405 nm is 0.7 × at a temperature of 120 ° C. and a frequency of 1 Hz.} The image display panel laminate according to any one of claims 1 to 24 , which comprises 10 ^{4 Pa or more.} The storage elastic modulus (G') of the adhesive layer (Y) after irradiation with light having an integrated light amount of 3000 (mJ / cm ^{2) at a wavelength of 405 nm is 2.0 × at a temperature of 120 ° C. and a frequency of 1 Hz.} The image display panel laminate according to any one of claims 1 to 24 , which comprises 10 ^{4 Pa or more.} The image display panel laminate according to any one of claims 1 to 26 , wherein the adhesive layer (Y) has a hot-melt property that softens or flows by heating.