WO2019031426A1

WO2019031426A1 - Photocurable pressure-sensitive adhesive sheet, photocurable pressure-sensitive adhesive sheet laminate, production method for photocurable pressure-sensitive adhesive sheet laminate, and production method for image display panel laminate

Info

Publication number: WO2019031426A1
Application number: PCT/JP2018/029334
Authority: WO
Inventors: 大希野澤; 福田　晋也; かほる石井; 誠稲永
Original assignee: 三菱ケミカル株式会社
Priority date: 2017-08-08
Filing date: 2018-08-06
Publication date: 2019-02-14
Also published as: TW201920565A; KR20220132017A; TWI785086B; KR102566971B1; CN111909622A; KR102566973B1; CN110997845B; TW202307167A; KR20230030047A; KR20220129682A; CN110997845A; CN111876091B; TW202309226A; KR102573795B1; TWI822414B; KR20200036015A; CN111909622B; CN111876091A; KR102566966B1

Abstract

The present invention relates to a pressure-sensitive adhesive sheet for use in laminating a resin member, the pressure-sensitive adhesive sheet being photocurable and exhibiting both surface conformance properties and anti-blistering properties. Proposed is a photocurable pressure-sensitive adhesive sheet for use in laminating a resin member (X) which has a light transmittance of 10% or less at a wavelength of 365 nm and a light transmittance of 60% or greater at a wavelength of 405 nm, characterized by including a pressure-sensitive adhesive layer (Y) having all of the following properties (1) to (3): (1) a gel content in the range of 0-60%; (2) a light transmittance of 89% or less at a wavelength of 390 nm and a light transmittance of 80% or greater at a wavelength of 410 nm; and (3) photocuring properties such that curing occurs upon irradiation with light having a wavelength of 405 nm.

Description

Photo-curable pressure-sensitive adhesive sheet, photo-curable pressure-sensitive adhesive sheet laminate, method for producing photo-curable pressure-sensitive adhesive sheet laminate, and method for producing image display panel laminate

The present invention is a pressure-sensitive adhesive sheet used to bond a resin member having an ultraviolet ray-cutting property that does not transmit ultraviolet light, and has a performance (referred to as “photo-curable”) that cures by irradiating light. The present invention relates to a photocurable adhesive sheet.

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), an electroluminescence display (ELD) and protection provided on the front side (viewing side) The space between the panel and the touch panel member is filled with an adhesive to suppress reflection of incident light or light emitted from a display image at the air layer interface.

As a method of filling the gaps between the components for such an image display device with a pressure-sensitive adhesive, there is a method of filling the gaps with a liquid adhesive resin composition containing an ultraviolet-curable resin and irradiating it with ultraviolet rays to cure. It is known (patent document 1).

There is also known a method of filling a space between components for an image display device using an adhesive sheet. For example, Patent Document 2 discloses a method in which a pressure-sensitive adhesive sheet primary-crosslinked by ultraviolet light is attached to an image display device constituting member, and then the adhesive sheet is irradiated with ultraviolet light through the image display device constituting member to perform secondary curing .

According to Patent Document 3, when laminating an image display device constituting member having a step portion on the bonding surface via the transparent double-sided adhesive sheet, it is possible to fill the step portion and to fill every corner. Furthermore, as a new transparent double-sided adhesive sheet capable of alleviating the distortion generated in the adhesive sheet and maintaining the foam resistance under high temperature and high humidity environment without impairing the manageability, one or more types of (meta ) An 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 of a wavelength of 405 nm Dynamic storage modulus at 60 ° C. determined by the shear method, which contains the visible light polymerization initiator (B) having a coefficient of 10 or more, and determined by the tension method at 60 ° C. E divided by G ') (E A transparent double-sided adhesive sheet in a B-stage state has been proposed in which '/ G') is 10 or more.

International Publication No. 2010/027041 Patent No. 4971529 gazette JP 2014-152295 A

As described above, when two image display device components are attached using the photocurable adhesive sheet, after two image display device components are primarily attached via the adhesive sheet, one of the image displays is displayed. It is possible to irradiate ultraviolet light from the outside of the device constituting member, and ultraviolet-cure the adhesive sheet through the image display device constituting member for secondary sticking.
According to such a method, the primary adhesion can be performed while filling up the unevenness of the adherend surface, and furthermore, since the adhesion reliability can be further enhanced by finally curing with ultraviolet rays, the members to be bonded ( "Step absorptivity" in the case where the adhesion surface of "a bonding member" is uneven as well as "reliability against foaming" after bonding can be made compatible.

For example, in an in-vehicle image display device, a front panel made of a resin is used to prevent scattering of glass, and a resin member such as a conductive member or a polarizing plate may be disposed on the inner side thereof. In this case, since it is necessary to prevent deterioration such as yellowing of the front panel and the conductive member disposed on the inner side thereof such as the conductive member and the polarizing plate, the resin member on the side exposed to the ultraviolet rays It has been practiced to incorporate an ultraviolet absorber to have the ability to absorb ultraviolet radiation.
However, in this case, as described above, it is not possible to irradiate the ultraviolet light from the outside of the image display device constituting member and to cure the pressure sensitive adhesive sheet through the image display device constituting member.
Therefore, when bonding a resin-made front panel together, it is compelled to use a non-photo-curable pressure-sensitive adhesive sheet which does not have photo-curing property, which is sufficiently cured to the extent that it has anti-foaming reliability.
However, such a non-photocurable pressure-sensitive adhesive sheet is not necessarily satisfactory in terms of step absorbability.

The present invention can be bonded to a resin member having an ultraviolet ray-cut property that does not transmit ultraviolet light, and the step absorbability in the case where the adhesion surface of the bonding member is uneven, and the anti-foaming reliability after bonding. It is intended to provide a new adhesive sheet that can be compatible.

The present invention is a resin member having an ultraviolet ray cutting property which does not transmit ultraviolet light, that is, a resin member having 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 (X) A photocurable pressure-sensitive adhesive sheet used to bond the
A photocurable pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer (Y) having all the following characteristics (1) to (3) is proposed.
(1) The gel fraction (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.

In the present invention, the photocurable pressure-sensitive adhesive sheet is laminated with a resin member (X) having 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. A photocurable pressure-sensitive adhesive sheet laminate having the following constitution is proposed.

Since the photocurable adhesive sheet proposed by the present invention has a gel fraction of 0 to 60% before photocuring, it is possible to obtain step absorbability that fills in steps such as irregularities on the adherend surface, while having a wavelength of 390 nm Has a light transmittance of 89% or less and has a photo-curing property that is cured by irradiation with light having a wavelength of 405 nm, so the resin member (X) to be bonded has a light transmittance of 10 at a wavelength of 365 nm. %, 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 cohesion is increased to enhance the anti-foaming reliability after bonding. You can get
Moreover, since the light transmittance at a wavelength of 410 nm is 80% or more, the light-curable adhesive sheet proposed by the present invention has a sufficiently low yellowness required for bonding of optical members requiring transparency ( The effect that YI) can be achieved can be obtained.

The light-curable pressure-sensitive adhesive sheet laminate proposed by the present invention can obtain step absorbability as described above, while the pressure-sensitive adhesive layer (Y) of the light-curable pressure-sensitive adhesive sheet is from the outside of the resin member (X) When irradiated with light having a wavelength of 405 nm through the resin member (X), the resin member (X) has a photocurability that increases by 10% or more as a difference in gel fraction, so the resin member (X) By irradiating the light having a wavelength of 405 nm through X), the pressure-sensitive adhesive layer (Y) can be cured, and the cohesive strength can be enhanced to obtain the anti-foaming reliability after bonding.

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

<< 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 properties.

The pressure-sensitive adhesive sheet is a pressure-sensitive adhesive sheet having a photo-curing property that is cured by irradiation with light. At this time, the pressure-sensitive adhesive sheet may be cured (also referred to as “temporary curing”) in a state where a room for photocuring remains, or may not be cured yet, and may be photocurable. It may be one having uncured (referred to as "uncured").
If the pressure-sensitive adhesive sheet is temporarily cured or uncured, the pressure-sensitive adhesive sheet can be photocured (also referred to as “main-cured”) after the pressure-sensitive adhesive sheet is attached to an adherend. As a result, the cohesion can be enhanced to improve adhesion.

As a preferable form of the present pressure-sensitive adhesive sheet having the above-mentioned temporarily cured or uncured and property capable of being fully cured, that is, photocurable which is cured by irradiation of light having a wavelength of 405 nm, 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, so that the visible light initiator (c) is used. It is an adhesive layer that can be fully cured.
(2) The adhesive layer (Y) is temporarily cured to have a gel fraction of 60% or less by the hydrogen abstraction type visible light initiator (c-2) among the visible light initiators (c) described below And an adhesive layer capable of main curing with the visible light initiator (c-2).
(3) The pressure-sensitive adhesive layer (Y) retains the sheet shape uncured and can be fully cured by the visible light initiator (c) by containing the visible light initiator (c) described below Adhesive layer.

As a method of forming the adhesive layer (Y) of the above (1), for example, a visible light initiator (c) and a (meth) acrylic acid ester (co) polymer (a) having a functional group (i), Crosslinker (b) such as a compound having a functional group (ii) reacting with the functional group (i) and, if necessary, a photopolymerizable compound (especially polyfunctional monomer) having a carbon-carbon double bond And a method of forming a pressure-sensitive adhesive layer (Y) by heating or curing a composition (an example of the present resin composition described later) containing a silane coupling agent (d) according to necessity. it can.
According to this 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. By curing (crosslinking), an adhesive layer (Y) is formed. By forming the adhesive layer (Y) in this manner, the visible light initiator (c) can be present in the adhesive layer (Y) while 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, a case is particularly preferable in which the (meth) acrylic acid ester copolymer (a) has a hydroxyl group (using a hydroxyl group-containing monomer described below) and the compound has an isocyanate group. It is.

Further, the compound having the functional group (ii) may further have a radically polymerizable functional group such as a (meth) acryloyl group. Thereby, the light of the (meth) acrylic acid ester (co) polymer by the radical polymerizable functional group, specifically, the light of the (meth) acrylic acid ester copolymer having an active energy ray crosslinkable structural site described below The adhesive layer (Y) can be formed while maintaining the curing (crosslinking) property. More specifically, when the (meth) acrylic acid ester (co) polymer (a) has a hydroxyl group (using a 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 preferred examples.
Thus, cohesive force after photocuring (crosslinking) without using the crosslinking agent (b) by utilizing the crosslinking reaction of (meth) acrylic acid ester (co) polymers by the radically polymerizable functional group Is more preferable because it has the advantage of being easy to raise efficiently and having excellent reliability.

In addition, about preferable forms etc. of a preferable acrylic acid ester (co) polymer (a), the said crosslinking agent (b), the said visible light initiator (c), and a silane coupling agent (d) about points other than the above, etc. Is described below.

As a method for forming the adhesive layer (Y) of the above (2), for example, a method of using a hydrogen abstraction type visible light initiator (c-2) described below as the visible light initiator (c) may be mentioned it can. The hydrogen abstraction type disclosing agent can be re-used as a visible light initiator because once it is excited, the unreacted one of the initiators returns to the ground state. Thus, the visible light curing (crosslinking) property by the visible light initiator can be maintained even after temporary curing by visible light irradiation by using the hydrogen abstraction type visible light initiator.
Points other than the above and preferred embodiments of the visible light initiator (c-2) will be described below.

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

It is preferable to use this adhesive sheet in order to bond resin member (X) mentioned later.

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

<Adhesive layer (Y)>
The adhesive layer (Y) preferably has all of the following properties (1) to (3).
(1) The gel fraction in a normal state, ie, the state before light irradiation (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.

If the adhesive layer (Y) has hot melt properties that soften or flow by heating, and there is a step such as unevenness on the adherend surface of the bonding member, the adhesive becomes even easier to every corner of the step It is preferable because it can be filled with the aluminum oxide, and the step absorbability can be further enhanced.
From this point of view, the pressure-sensitive adhesive layer (Y) is preferably the pressure-sensitive adhesive layer (Y) of the above (3).

(Gel fraction)
The gel fraction (gel fraction before light irradiation X1) of the adhesive layer (Y) is preferably in the range of 0 to 60%.
If the gel fraction of the adhesive layer (Y) is 60% or less, the amount of uncrosslinked components that can be cured by light irradiation is large enough (temporarily cured or uncured), and so flexible, And, it is preferable from the viewpoint that “gel fraction after light irradiation X2-gel fraction before light irradiation X1” can be 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, still more preferably 50% or less.

In order to adjust the gel fraction (gel fraction before light irradiation X1) of the adhesive layer (Y) to the above range, the residual catalyst is sufficiently removed during polymerization of the present resin composition and processing of the adhesive sheet described later, or It is sufficient to prevent an unintended curing (crosslinking) reaction by heat, light, etc. from proceeding before main curing by using a polymerization inhibitor, an antioxidant or the like. In order to temporarily cure, the integrated light quantity of the light to be irradiated may be sufficiently reduced, and the uncrosslinked component may be sufficiently increased. However, it is not limited to such a method.

Furthermore, the adhesive layer (Y) is preferably provided with a photocurable property that is cured by irradiation with light having a wavelength of 405 nm, and as the degree of the photocurable property, for example, the resin member from the outside of the resin member (X) When irradiated with light of wavelength 405 nm via (X), the light curing increases by 10% or more, particularly 15% or more, particularly 20% or more, particularly 30% or more, among them, 50% or more as a difference in gel fraction It is preferable to have a sex.
Note that “irradiate light with a wavelength of 405 nm” means to measure light with a wavelength of 405 nm as a photosensitivity peak measured with an ultraviolet actinometer, and with light sensitivity whose foot broadens to a wavelength range of 320 to 470 nm. Means

Above all, when the adhesive layer (Y) is irradiated with light having an integrated light quantity 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) Between the gel fraction before light irradiation (gel fraction before light irradiation X1) and the 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 in which the gel fraction before light irradiation X1) 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 a cumulative light quantity of 3000 (mJ / cm ² ) at a wavelength of 405 nm (“ It is preferable to have a photo-curing property such that the gel fraction X2 ′ ′ after irradiation is 50% or more.
A gel fraction difference of 10% or more of the adhesive layer (Y) before and after photocuring is preferable because it can be highly cohesive even in a severe high temperature and high humidity environment and the like, and the antifoaming reliability can be enhanced.
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, 20% or more, 30% or more, 50% or more among them. Is more preferred.
In order to adjust the gel fraction difference of the pressure-sensitive adhesive layer (Y) before and after the light irradiation to be in the above-mentioned range, it is sufficient that the wavelength 405 nm be absorbed by the photo initiator. However, it is not limited to such a method.

Note that "integrated light quantity at wavelength 405 nm" is the total amount of irradiation energy received per unit area, and among the light irradiated by a high-pressure mercury lamp etc., an ultraviolet integrated light meter "UIT-250" Indicates the total amount of light irradiation energy measured using a company) and a light receiver “UVD-C 405” (manufactured by Ushio Electric Co., Ltd.), and the photosensitive characteristics of the light receiver (wavelength range of 320 to 470 nm with 405 nm as a photosensitive peak) It refers to the integrated light quantity in the wavelength region according to the light sensitivity which has a wide base). More specifically, it refers to the integrated light amount obtained in accordance with the method described in the examples.

(Light transmittance)
The pressure-sensitive 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.
In an adhesive composition containing a photoinitiator having absorption in the ultraviolet to visible light region around a wavelength of 400 nm, the larger the light absorption of the photoinitiator, the lower the light transmittance at a wavelength of 390 nm derived from the absorption. The photosensitivity is good and the curing tends 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) becomes yellow and difficult to use for an optical member.

As a measure of the above, if the light transmittance at a wavelength of 390 nm is 89% or less, it is preferable because the adhesive layer (Y) can ensure sufficient visible light curability, and the light transmittance at a wavelength of 410 nm is 80% or more These are preferable because they can achieve a sufficiently low yellowness (YI) necessary for bonding of optical members that require transparency.
Therefore, in the pressure-sensitive adhesive layer (Y), the light transmittance at a wavelength of 390 nm is preferably 89% or less, and more preferably 88% or less.
The light transmittance at a wavelength of 410 nm is preferably 80% or more, more preferably 85% or more, and still more preferably 90% or more.
In order to make the light transmittance of the adhesive layer (Y) as described above, among the initiators having absorption in visible light, the bottom of the absorption peak reaches sufficiently to 390 nm, while the absorption peak is at 410 nm. What has a small absorption peak characteristic may be used. However, it is not limited to such a method.

(Storage elastic modulus)
The storage elastic modulus (G ′) of the adhesive layer (Y) is preferably 0.9 × 10 ⁵ Pa or less at a temperature of 25 ° C. and a frequency of 1 Hz.
By having such visco-elastic properties, the present pressure-sensitive adhesive sheet can obtain step absorbability that is particularly excellent for filling in steps such as irregularities on 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 at a temperature of 25 ° C. and a frequency of 1 Hz, and in particular 0.8 × 10 ⁵ Pa or less It is further preferred that

The pressure-sensitive 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 quantity of 3000 (mJ / cm ² ) at a wavelength of 405 nm. It is preferable to be 10 ⁴ Pa or more.
When the storage elastic modulus (G ') of the adhesive layer (Y) after photocuring is in the above range, when the laminate with the resin member (X) is subjected to a high temperature test, a high temperature high humidity test, etc. It is preferable at the point which can suppress that an adhesion layer (Y) foams by 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 in particular 1.0 × It is more preferable that it is 10 ⁴ Pa or more, and it is further more preferable that it is 2.0 × 10 ⁴ Pa or more among them.

By the way, in an image display device having a touch panel function, a glass sensor, a film sensor, a polarizing plate glass (on-cell type or in-cell type with a sensor incorporated therein) as a touch sensor disposed on the back side of the front panel / adhesive layer And so on, depending on the module design, and the susceptibility to failure in environmental testing differs depending on the configuration of the sensor members.
When the pressure-sensitive adhesive layer (Y) is used in a resin member (X) / pressure-sensitive adhesive layer (Y) / glass sensor configuration as a result of experimental examination in the present invention, the storage elastic modulus of the pressure-sensitive adhesive layer (Y) ( The preferable range of G ') is as the above range, but when it is used by bonding in the configuration of the resin member (X) / adhesive layer (Y) / film sensor, the film sensor usually has a thin thickness of 100 μm or less Since the rigidity is small and the reliability improvement effect by the silane coupling agent is low compared to the reliability improvement effect by the glass material, foaming is more likely to occur in the wet heat environment test than in the case of the glass sensor, and the storage elastic modulus is further enhanced. (G ') is required.

Therefore, the storage elasticity of the adhesive layer (Y) after photocuring in the case where the adhesive layer (Y) is bonded and used in the configuration of the resin member (X) / adhesive layer (Y) / film sensor. rate (G '), i.e., integrated light quantity 3000 (mJ / cm ²⁾ pressure-sensitive adhesive layer when irradiated with light which is storage modulus (Y) (G at a wavelength 405 nm' as a preferable range), the 2 .0 × 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), and if necessary, a crosslinking agent (b), and further, if necessary, a silane coupling agent (D) It can be formed from a pressure-sensitive adhesive composition (referred to as "the present resin composition") further containing other materials as needed.

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

In addition, "(meth) acrylic" means acryl and methacryl, "(meth) acryloyl" means acryloyl and methacryloyl, and "(meth) acrylate" means including acrylate and methacrylate, respectively. It is. The term "(co) polymer" is meant to encompass polymers and copolymers. Also, the term "sheet" conceptually includes sheets, films, and tapes.

Examples of the (meth) acrylic acid ester (co) polymer (a) include a copolymer obtained by polymerizing monomer components copolymerizable therewith, in addition to homopolymers of alkyl (meth) acrylate, for example. It can be mentioned. For example, in addition to homopolymers of alkyl (meth) acrylates, copolymers obtained by polymerizing monomer components 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, such as (a) a carboxyl group-containing monomer 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 referred to as “copolymerizable monomer C”). ), (D) epoxy group-containing monomer (hereinafter also referred to as “copolymerizable monomer D”), (e) amide group-containing monomer (hereinafter also referred to as “copolymerizable monomer E”), (f) vinyl monomer Hereinafter, it is also referred to as "copolymerizable monomer F"), (g) (meth) acrylate monomers having 1 to 3 carbon atoms in the side chain (hereinafter also referred to as "copolymerizable monomer G"), and Also referred to as h) macromonomer (hereinafter "copolymerizable monomer H".) Can be mentioned a copolymer of a monomer component containing one or more monomers selected from.

The alkyl (meth) acrylate is preferably a linear or branched alkyl (meth) acrylate having 4 to 18 carbon atoms in its side chain.
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 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-trimethylcyclohexane (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyl oxyethyl (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 a linear or branched alkyl (meth) acrylate having 4 to 18 carbon atoms It is particularly preferred to include one or more.

Examples of the copolymerizable monomer A include (meth) acrylic acid, 2- (meth) acryloyloxyethyl hexahydrophthalic acid, 2- (meth) acryloyloxypropyl hexahydrophthalic acid, 2- (meth) acryloyloxyethyl Phthalic acid, 2- (meth) acryloyloxypropyl phthalic acid, 2- (meth) acryloyloxyethylmaleic acid, 2- (meth) acryloyloxypropylmaleic acid, 2- (meth) acryloyloxyethyl succinic acid, 2- ( Mention may be made of meta) acryloyloxypropylsuccinic acid, crotonic acid, fumaric acid, maleic acid, itaconic acid. These may be used alone or in combination of two or more.

Examples of the copolymerizable monomer B include hydroxyalkyls such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate and the like. Mention may be made of meta) acrylates. These may be used alone or in combination of two or more.

Examples of the copolymerizable monomer C include aminoalkyl (meth) acrylates such as aminomethyl (meth) acrylate, aminoethyl (meth) acrylate, aminopropyl (meth) acrylate, aminoisopropyl (meth) acrylate and the like, N-alkylamino Mention may be made of N, N-dialkylaminoalkyl (meth) acrylates such as alkyl (meth) acrylates, N, N-dimethylaminoethyl (meth) acrylates, N, N-dimethylaminopropyl (meth) acrylates and the like. These may be used alone or in combination of two or more.

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 used alone or in combination of two or more.

Examples of the copolymerizable monomer E include (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N-butyl (meth) acrylamide, N-methylol (meth) acrylamide, N-methylolpropane (meth) acrylamide, Mention may be made of N-methoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, diacetone (meth) acrylamide, maleic acid amide, maleimide. These may be used alone or in combination of two or more.

As said copolymerizable monomer F, the compound which has a vinyl group in a molecule | numerator can be mentioned. As such compounds, (meth) acrylic acid alkyl esters having 1 to 12 carbon atoms in the alkyl group, functional monomers having a functional group such as a hydroxyl group, an amide group and an alkoxyl alkyl group in the molecule, and 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 illustrated. These may be used alone or in combination of two or more.
Among the above, it is preferable to select an alkyl (meth) acrylate and the above-mentioned 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 used alone or in combination of two or more.
Among the above, it is preferable to select an alkyl (meth) acrylate and the above-mentioned copolymerizable monomer G other than the alkyl (meth) acrylate.

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

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 made a graft copolymer. For example, a (meth) acrylic acid ester copolymer (a-1) comprising a graft copolymer provided with a macromonomer as a branch component can be obtained.
Therefore, the properties of the main chain and the side chain of the graft copolymer can be changed by the selection and blending ratio of 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, linear or branched alkyl (meth) acrylate having 4 to 18 carbon atoms in the side chain, the above copolymerizable monomer A, the above copolymerizable monomer B, the above copolymerizable monomer G and the like are exemplified. These may be used alone or in combination of two or more.

Among them, the main 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 (but 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 And cyclohexyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate and methyl methacrylate.
In addition, examples of hydrophobic vinyl monomers include vinyl acetate, styrene, t-butylstyrene, α-methylstyrene, vinyl toluene, alkyl vinyl monomers and the like.

On the other hand, as the above-mentioned hydrophilic (meth) acrylate monomer, methyl acrylate and an ester having a polar group are preferable. For example, methyl acrylate, (meth) acrylic acid, tetrahydrofurfuryl (meth) acrylate, hydroxyethyl (meth) Hydroxyl group-containing (meth) acrylates such as acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, glycerol (meth) acrylate, (meth) acrylic acid, 2- (meth) acryloyloxyethyl hexahydrophthalic acid, 2- (Meth) acryloyloxypropylhexahydrophthalic acid, 2- (Meth) acryloyloxyethyl phthalic acid, 2- (Meth) acryloyloxypropyl phthalic acid, 2- (Meth) acryloyloxyethyl maleate Acid, 2- (Meth) acryloyloxypropylmaleic acid, 2- (Meth) acryloyloxyethylsuccinic acid, 2- (Meth) acryloyloxypropylsuccinic acid, crotonic acid, fumaric acid, maleic acid, itaconic acid, monomethyl maleate , Carboxyl group-containing monomers such as monomethyl itaconate, acid anhydride group-containing monomers such as maleic anhydride and itaconic anhydride, glycidyl (meth) acrylate, glycidyl α-ethyl acrylate, 3,4- (meth) acrylate Examples thereof include epoxy group-containing monomers such as epoxy butyl, alkoxypolyalkylene glycol (meth) acrylates such as methoxy polyethylene glycol (meth) acrylate, N, N-dimethyl acrylamide, hydroxyethyl acrylamide and the like.

The macromonomer as the copolymerizable monomer H is preferably one having a functional group such as a radical polymerizable group, a hydroxyl group, an isocyanate group, an epoxy group, a carboxyl group, an amino group, an amide group or a thiol group. .
As said macromonomer, what has a radically polymerizable group copolymerizable with another monomer is preferable. One or two or more radically polymerizable groups may be contained, and among them, one is particularly preferable.
Even when the above-mentioned macromonomer has a functional group, one or two or more functional groups may be contained, and among them, one is particularly preferable.
Further, either or both of the radically polymerizable group and the functional group may be contained. When both a radically polymerizable group and a functional group are contained, a functional group other than any of a functional group added with a polymer unit comprising another monomer or a radically polymerizable group copolymerized with another monomer or radical polymerization The sex group may be two or more.

The terminal functional group of the macromonomer is, for example, radical polymerizable group such as methacryloyl group, acryloyl group, vinyl group, hydroxyl group, isocyanate group, epoxy group, carboxyl group, amino group, amide group, thiol group etc. Functional groups can be mentioned.
Among them, those having a radically polymerizable group copolymerizable with other monomers are preferable. One or two or more radically polymerizable groups may be contained, and among them, one is particularly preferable. Even when the macromonomer has a functional group, one or more functional groups may be contained, and among them, one is particularly preferable.
Also, either or both of the radically polymerizable group and the functional group may be contained. When both a radically polymerizable group and a functional group are contained, a functional group other than any of a functional group added with a polymer unit comprising another monomer or a radical polymerizable group copolymerized with another monomer or radical polymerization The sex group may be two or more.

The number average molecular weight of the macromonomer is preferably 500 to 20,000, and more 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 heat melting temperature (hot melt temperature) of the pressure-sensitive adhesive sheet, and therefore, preferably 30 ° C. to 120 ° C., and more preferably 40 ° C. or higher. It is more preferable that the temperature is not higher than ° C, and more preferably not lower than 50 ° C or not higher than 100 ° C.

If the macromonomer has such a glass transition temperature (Tg), it is possible to maintain excellent processability and storage stability by adjusting the molecular weight, and adjust so as to be hot-melted 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).

In addition, at room temperature, the branch components can attract each other to maintain physical crosslinking as a pressure-sensitive adhesive composition, and the physical crosslinking can be solved 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, and more preferably 6% by mass or more or 25% by mass or less It is more preferable to contain in the ratio of 8 mass% or more or 20 mass% or less among them.
The number average molecular weight of the macromonomer is preferably 500 to 100,000, more preferably less than 8,000, and more preferably 800 or more and less than 7500, and still more preferably 1,000 or more and 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 portion of (meth) acrylic acid ester copolymer (a) or (meth) acrylic acid ester co-weight in the presence of a visible light initiator (c) described later. It is a structural site which can react with a curing component other than the combination (a) to form a crosslinked structure.

The active energy ray crosslinkable structural moiety is, 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. It can be mentioned.
When the polymer chain of the (meth) acrylic acid ester (co) polymer (a) has an unsaturated double bond, the polymer chains can be directly polymerized with each other even when no crosslinking agent is contained. , Storage modulus (G ') can be raised to a high level.
In addition, when performing active energy ray irradiation, any light source containing light with a wavelength of 405 nm may be used, and from the curing speed, the availability of the irradiation device, the price etc, visible light LED light source, high pressure mercury A lamp etc. can be used.

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) And a carbon-carbon double such as a functional group capable of reacting with the functional group (for example, 2-isocyanatoethyl (meth) acrylate etc.) 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 a linear alkyl group having 10 to 24 carbon atoms. The (meth) acrylate (co) polymer (a-2) of the monomer component is preferred.
Examples of such (meth) acrylic acid ester (co) polymer (a-2) include decyl (meth) acrylate (carbon number of alkyl group: 10), lauryl (meth) acrylate (carbon number: 12), tridecyl (co) Examples thereof include meta) acrylate (carbon number 13), hexadecyl (meth) acrylate (carbon number 16), stearyl (meth) acrylate (carbon number 18), behenyl (meth) acrylate (carbon number 22) and the like. 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, it is possible to lower the dielectric constant and to lower the glass transition temperature of the acrylic resin, It is preferable to use an alkyl methacrylate, particularly preferably one having an alkyl group having 12 to 20 carbon atoms, and most preferably stearyl methacrylate, lauryl methacrylate or 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 based on the total amount of the (co) polymerization component, and preferably 60 to It is 83% by weight, particularly preferably 70 to 80% by weight. Within the above range, there is no possibility that the dielectric constant is increased or the thermal stability of the resin is reduced.

[Crosslinking agent (b)]
As the crosslinking agent (b), a crosslinking agent having at least double bond crosslinking 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 crosslinking agent which has can be mentioned and you may use it in combination of 1 type, or 2 or more types.
In particular, by using two or more kinds of crosslinking agents in combination, a high storage modulus (G ') can be achieved even when the total blending amount is the same as compared to the case where each of them is used alone.
Therefore, it is more preferable to use two or more types of crosslinking agents (b) in combination.
Also included is an embodiment in which the crosslinking agent (b) is chemically bonded to the (meth) acrylic acid ester (co) polymer (a).

Among them, it is preferable to use a photopolymerizable compound having a carbon-carbon double bond, in particular, a polyfunctional (meth) acrylate. Here, polyfunctional refers to those having two or more crosslinkable functional groups. In addition, you may have three or more and four or more crosslinkable functional groups as needed.
The crosslinkable functional group may be protected by a deprotectable protective group.

Examples of the polyfunctional (meth) acrylate include 1,4-butanediol di (meth) acrylate, glycerin di (meth) acrylate, neopentyl glycol di (meth) acrylate, glycerin glycidyl ether di (meth) acrylate, 6-Hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, tricyclodecane dimethacrylate, tricyclodecane dimethanol di (meth) acrylate, bisphenol A polyethoxy di (meth) acrylate, bisphenol A poly Propoxydi (meth) acrylate, bisphenol F polyethoxydi (meth) acrylate, ethylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylol Lopant trioxyethyl (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, propoxylated 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, dipentae Stilitol penta (meth) acrylate, tripentaerythritol hexa (meth) acrylate, tripentaerythritol penta (meth) acrylate, hydroxybivalate neopentyl glycol di (meth) acrylate, ε-caprolactone of hydroxy bivalerate neopen glycol UV curable polyfunctional (meth) acrylics such as adducts of di (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolpropane polyethoxy tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate and the like In addition to monomers, polyester (meth) acrylates, epoxy (meth) acrylates, urethane (meth) acrylates, and polyfunctional (meth) acrylics such as polyether (meth) acrylates Oligomer 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 strength, those having a structure in which the distance between crosslink points in the crosslink structure to be formed is short and the crosslink density is dense are preferable. Modified trifunctional or higher polyfunctional (meth) acrylate is preferable, and pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol hexa (meth) acrylate, di Pentaerythritol penta (meth) acrylate, tripentaerythritol hexa (meth) acrylate, tripentaerythritol penta (meth) acrylate, trimethylolpropane tri (meth) acrylate, ditrimethylolpropane salt (Meth) polyfunctional (meth) acrylate is selected from the group consisting of acrylate (b-1) is preferable.
The polyfunctional (meth) acrylates (b-1) may be used alone or in combination of two or more (as a mixture).

Moreover, when using said polyfunctional (meth) acrylate (b-1) as a crosslinking agent, said (meth) acrylic acid ester (a) is a hydrophilic component as a polar component from a compatibility viewpoint. It is preferable that it is a copolymer of the monomer component to contain.
When the (meth) acrylic acid ester (a) contains a polar component, the compatibility with the above-mentioned polyfunctional (meth) acrylate (b-1) becomes good, and it becomes easy to mix at the time of mixing, and it is long in uncrosslinked state There is no possibility that phase separation occurs when stored for a long time, and the haze value is not increased.

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

The content of the crosslinking agent (b) is 0.5 to 50 parts by mass, in particular 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 proportion 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 a wavelength of at least 390 nm, 405 nm and 410 nm, for example, light in the wavelength range of 380 nm to 700 nm, to give (meth) acrylate (co It is preferable that it is a visible light initiator which becomes the starting point of the reaction of the polymer (a).
However, the visible light initiator (c) may generate radicals only by irradiation of visible light, or may generate radicals also by irradiation of light in wavelength regions other than the visible light region. It may be.

The visible light initiator (c) preferably has an absorption coefficient of 10 mL / (g · / cm) or more at a wavelength of 405 nm, and more preferably 15 mL / (g · / cm) or more, among them 25 mL / (g · / g). More preferably, it is cm) or more. When the absorption coefficient at a wavelength of 405 nm is 10 mL / (g · / cm) or more, curing (crosslinking) by irradiation of 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 preferable. In addition, you may use together with the photoinitiator whose light absorption coefficient in wavelength 405nm is less than 10 mL / (g * / cm).

Photoinitiators are roughly classified into two according to a radical generation mechanism, and they are a cleavage type photoinitiator capable of generating a radical by cleaving the single bond of the photoinitiator itself, a photoexcited initiator, and other components in the system. It is roughly classified into a hydrogen abstraction type photoinitiator capable of forming an exciplex with a hydrogen donor and transferring hydrogen of the hydrogen donor.

Among these, the cleavage type photoinitiator is decomposed when generating radicals by light irradiation to become another compound, and once excited, it does not have a function as a reaction initiator. For this reason, it is preferable because it does not remain as an active species in the pressure-sensitive adhesive after completion of the crosslinking reaction, and there is no possibility of causing unexpected photodegradation and the like in the pressure-sensitive adhesive.
In addition, with regard to coloring specific to the photoinitiator, there has been a possibility of coloring in the case where a cleavable visible light initiator (c-1) is conventionally added which cures the adhesive by curing with visible light. Therefore, as the visible light initiator (c), it is preferable to appropriately select one that loses absorption in the visible light range of the reaction decomposition product and is decolored.
On the other hand, hydrogen abstraction type photoinitiator can not only maintain the function as a reaction initiator even when irradiated with light multiple times, but also cleave type photo initiation at the time of radical generation reaction by irradiation of active energy rays such as ultraviolet light. Since no decomposition product such as an agent is generated, it is difficult to become a volatile component after completion of the reaction, which is useful in that damage to the adherend can be reduced.
Therefore, a hydrogen extraction type visible light polymerization initiator (c-2) which is excited by visible light to start polymerization is particularly preferable.

Examples of the cleavable visible light initiator (c-1) include 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxycyclohexyl phenyl ketone, and 2-hydroxy-2-methyl-1-one. Phenyl-propan-1-one, 1- (4- (2-hydroxyethoxy) phenyl) -2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1- [4- {4- (2-hydroxy-2-methyl-propionyl) benzyl} phenyl] -2-methyl-propan-1-one, oligo (2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) propanone ), Methyl phenylglyoxylic acid, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butan-1-one, 2-methyl-1- [ -(Methylthio) phenyl] -2-morpholinopropan-1-one, 2- (dimethylamino) -2-[(4-methylphenyl) methyl) -1- [4- (4-morpholinyl) phenyl] -1 -Butanone, bis (2,4,6-trimethylbenzoyl) -phenyl phosphine oxide, 2,4,6-trimethyl benzoyl diphenyl phosphine oxide, (2,4,6-trimethyl benzoyl) ethoxyphenyl phosphine oxide, or the like Derivatives of and the like.
Among these, bis (2,4,6-trimethyl benzoyl) -phenyl phosphine oxide, 2,4,6-trimethyl benzoyl diphenyl phosphine oxide, Acyl phosphine oxide type photoinitiators such as -trimethyl benzoyl) ethoxy phenyl phosphine oxide and bis (2, 6- dimethoxy benzoyl) 2, 4 4- trimethyl pentyl oxide are preferable.

Examples of the hydrogen-extractable visible light initiator (c-2) include bis (2-phenyl-2-oxoacetic acid) oxybisethylene, phenylglyoxylic acid methyl ester, oxy-phenyl-acetic acid 2- [4] Mixture of 2-oxo-2-phenyl-acetoxy-ethoxy] ethyl ester and oxy-phenyl-acetic acid 2- [2-hydroxy-ethoxy] ethyl ester, thioxanthone, 2-chlorothioxanthone, 3-methylthioxanthone, 2, Examples include 4-dimethylthioxanthone, anthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 2-aminoanthraquinone, camphorquinone and derivatives thereof.
Among them, phenylglyoxylic acid methyl ester, oxy-phenyl-acetic acid 2- [2-oxo-2-phenyl-acetoxy-ethoxy] ethyl ester and oxy-phenyl-acetic acid 2- [2-hydroxy- It is preferable that it is 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 above-mentioned substances. Any one or a derivative of the visible light initiator (c) listed above may be used, or two or more may be used in combination.
Further, in addition to the visible light initiator (c), one that generates radicals only by irradiation of 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, in particular 0.5 parts by mass or more or 5 parts by mass or less, relative to 100 parts by mass of the (meth) acrylate (co) polymer (a) in the adhesive layer (Y), among which It is preferable to contain in the ratio of 1 mass part or more or 3 mass parts or less.
By setting the content of the visible light initiator (c) in the above range, appropriate reaction sensitivity to visible light can be obtained.

[Silane coupling agent (d)]
The silane coupling agent (d) can improve the adhesion, in particular, the adhesion to the glass material.
Examples of the silane coupling agent include compounds having a hydrolyzable functional group such as an alkoxy group together with an unsaturated group such as a vinyl group, an acryloxy group, and a methacryloxy group, an amino group, an epoxy group, etc. .
Specific examples of the silane coupling agent include N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane, N- (β-aminoethyl) -γ-aminopropylmethyldimethoxysilane, 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 adhesion and less discoloration such as yellowing. It can be used.
The silane coupling agents 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 preferably 0.2 parts by mass or more or 3.0 parts by mass or less It is further preferred that
In addition, coupling agents, such as an organic titanate compound, can be effectively used similarly to a silane coupling agent.

[Other materials]
As a component other than the above contained in this resin composition which forms adhesion layer (Y), for example, a light stabilizer, an ultraviolet absorber, a metal deactivator, a metal corrosion inhibitor, an antiaging agent, antistatic Agents, hygroscopic agents, foaming agents, antifoaming agents, inorganic particles, viscosity modifiers, tackifier resins, photosensitizers, various additives such as fluorescent agents, reaction catalysts (tertiary amine compounds, quaternary ammonium compounds Compounds, tin lauryl acid compounds and the like can be mentioned.
In addition, you may contain suitably the well-known component mix | blended with a normal adhesive composition.
Further, each component may be used in combination of two or more.

Among the above, it is preferable that the present resin composition for forming the pressure-sensitive adhesive layer (Y) contains an ultraviolet absorber, among others. As described above, the pressure-sensitive adhesive layer (Y) is provided with a photo-curing property that is cured by irradiation with light having a wavelength of 405 nm, and thus does not inhibit the photo-curing even if it contains a UV absorber. For this reason, by containing an ultraviolet absorber, it is possible to combine excellent ultraviolet ray cutting properties without impairing the properties of the pressure-sensitive adhesive sheet.

Examples of the UV absorber include benzotriazole UV absorber, benzophenone UV absorber, and triazine UV absorber. In addition, the said ultraviolet absorber may be used individually or in combination of 2 or more types.
Among them, the UV absorber is particularly preferably a triazine-based UV absorber from the viewpoints of transparency, UV absorbability and compatibility.

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

Among them, the (meth) acrylic ester (co) polymer (a) is composed of 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 the combination of any functional group selected from them.
Further, a (meth) acrylic acid ester (co) polymer (a) is a linear or branched alkyl (meth) acrylate having 4 to 18 carbon atoms in the side chain as described above, and the above hydrophilic (meth) acrylate It is preferable that it is a copolymer which contains as a copolymerization component.
Furthermore, it is preferable that the crosslinking agent (b) is the above-mentioned polyfunctional (meth) acrylate (b-1).

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

Among them, the (meth) acrylic acid ester (co) polymer (a-1) is a linear or branched alkyl (meth) acrylate having 4 to 18 carbon atoms of the above-mentioned side chain as a skeleton component (stem component). It is preferable that it is a copolymer which contains the said hydrophilic (meth) acrylate as a copolymerization component.
The crosslinking agent (b) is preferably the above-mentioned polyfunctional (meth) acrylate (b-1).

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

When an adhesive layer (Y) is formed using the present resin composition having the above composition, an adhesive layer (Y) using the (meth) acrylic acid ester copolymer (a) or (a-1) as a base resin A) can exhibit self-adhesiveness, hold | maintaining sheet shape in a room temperature state, and can be filled with an adhesive to every [of the level | step difference of the adhesion surface of a bonding member]. In addition, the visible light initiator (c) can be photocured by visible light irradiation, and the cohesion can be enhanced by the photocuring to enhance the anti-foaming reliability.
Furthermore, by blending a silane coupling agent, it is possible to further improve the adhesion, particularly to the glass material.
Moreover, since the adhesive layer (Y) which uses (meth) acrylic acid ester copolymer (a-1) as a base resin has the hot-melt property which melts or flows when heated in addition to the above, it has higher step absorbability You can have

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

By using the present resin composition having the composition as described above, it is possible to form an adhesive layer (Y) which has been temporarily cured or uncured in a state in which a room for photocuring remains, and thereafter, once or once It can be photocured by two or more visible light irradiations. Thus, for example, after the present pressure-sensitive adhesive sheet is bonded to an adherend, the present pressure-sensitive adhesive sheet can be photocured ("mainly cured") by irradiation with visible light, and cohesion is enhanced by the main cure to enhance foam resistance Can be enhanced.
In particular, visible light curing after bonding, even when passing through a step of enhancing storage stability by temporary curing, for a (meth) acrylic acid ester (co) polymer which has high fluidity at normal temperature and storage stability is difficult The curing can be advanced by a post-process of
Furthermore, by blending a silane coupling agent, it is possible to further improve the adhesion, particularly to the glass material.

(Laminated structure)
As described above, when the pressure-sensitive adhesive layer (Y) is laminated, the pressure-sensitive adhesive layer (Y) using the present resin composition is preferably the outermost layer, from the viewpoint of foam resistance.
Under the present circumstances, it is preferable that it is 15 micrometers or more, and, as for the thickness of the adhesion layer (Y) as a front and back layer, it is more preferable that it is 20 micrometers or more. When the thickness of the adhesive layer (Y) is 15 μm or more, it is preferable in that there is little possibility that problems such as foaming may occur by pushing against the outgas pressure generated from the adherend member in the reliability test.

Moreover, it may be preferable to further provide another layer having a viscosity higher than that of the pressure-sensitive adhesive layer (Y), from the viewpoint of providing storage stability.
That is, an adhesive layer (Y) formed using a graft copolymer having a macromonomer is in an uncrosslinked state before photocuring, and such polyfunctional ((meth) acrylate monomer is The adhesive layer (Y) before photocuring may be a layer having a relatively low viscosity due to the action of the (meth) acrylate monomer component.
Therefore, in such a case, it is preferable to laminate another layer (Z) having a viscosity higher than that of the pressure-sensitive adhesive layer (Y) to the pressure-sensitive adhesive layer (Y).
For example, if it is a multilayer structure which consists of 3 layers of adhesive layer (Y) / layer (Z) / adhesive layer (Y), it can be equipped with the outstanding 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., and is preferably 1.5 to 5 kPa · s. It is more preferable that
In addition, this viscosity is a value measured according to the method as described in an Example.

In the case where the pressure-sensitive adhesive sheet has a multilayer 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 additionally providing impact absorption. Is preferable, and it is more preferable that the temperature is less than 10 ° C.
By having such a relatively low Tg, the pressure-sensitive adhesive sheet can improve low-temperature adhesion properties (such as low-temperature peel strength) and have impact absorption.
Therefore, from the viewpoint of impact absorption, the Tg after 405 nm light irradiation of the other layers laminated with the pressure-sensitive adhesive layer (Y) is less than 15 ° C., particularly less than 10 ° C., particularly less than 5 ° C. Particularly preferred.
In addition, said Tg is a value measured by the peak temperature of Tan (delta) of a dynamic viscoelasticity, and is a value measured according to the method as described in an Example in detail.

<Adhesive sheet with release film>
The pressure-sensitive adhesive sheet can also be a pressure-sensitive adhesive sheet with a release film.
For example, a single-layer or multi-layer sheet-like pressure-sensitive adhesive layer may be formed on a release film to form a release film-attached pressure-sensitive adhesive sheet.

As a material of this release film, a well-known release film can be used suitably.
As a material of the release film, for example, a silicone resin is applied to a film such as a polyester film, a polyolefin film, a polycarbonate film, a polystyrene film, an acrylic film, a triacetyl cellulose film, a fluorine resin film, A release paper or the like can be appropriately selected and used.

When the release film is laminated on both sides of the pressure-sensitive adhesive sheet, one release film may have the same lamination structure or material as the other release film or may have a different lamination structure or material. Good.
Also, they may have the same thickness or different thicknesses.
In addition, it is possible to laminate a release film having a different peeling force or a release film having a different thickness on both sides of the present 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 pressure-sensitive adhesive sheet, the progress of photopolymerization by irradiation of visible light is effectively prevented. Can.
From this point of view, the release film laminated on one side or both sides of the pressure-sensitive adhesive sheet preferably has a light transmittance of 40% or less at a wavelength of 410 nm or less, in particular 30% or less, and in particular 20% or less It is further preferred that

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 transmission of visible light and ultraviolet light, for example, polyester type, polypropylene type, A laminated film comprising an ultraviolet absorbing layer formed by coating a releasable slightly adhesive resin on one surface of a cast film or stretched film of a polyethylene type and coating a coating containing an ultraviolet absorber on the other surface It can be mentioned.
Moreover, what apply | coated the slightly adhesive resin which has the removability which mix | blended the ultraviolet absorber with one side of the cast film of polypropylene type and a polyethylene type | system | group and a polyethylene-type film and an oriented film can be mentioned.
Further, a cast film or a stretched film made of a polyester-based, polypropylene-based or polyethylene-based resin compounded with an ultraviolet absorber may be coated with a slightly adhesive resin having removability.
Also, a multilayer cast film or stretched film formed by molding a layer made of a resin not containing an ultraviolet absorber on one side or both sides of a layer made of a polyester type, polypropylene type or polyethylene type resin compounded with an ultraviolet ray absorbent. What apply | coated the slightly adhesive resin which has removability on one side can be mentioned.
In addition, a paint containing an ultraviolet absorber is applied to one surface of a cast film or stretched film made of polyester, polypropylene, or polyethylene resin to provide an ultraviolet absorption layer, and the surface is re-peeled on the ultraviolet absorption layer. What apply | coated the slightly adhesive resin which has property can be mentioned.
In addition, a paint containing an ultraviolet absorber is applied to one side of a cast film or stretched film made of a polyester, polypropylene, or polyethylene resin to provide an ultraviolet absorbing layer, and the other side has fine removability. What apply | coated the adhesive resin can be mentioned.
Furthermore, the other surface of the resin film made of a polyester, polypropylene, or polyethylene resin coated with a slightly adhesive resin having removability on one surface, and a separately prepared resin film, contain an ultraviolet absorber. What was laminated | stacked via an adhesive layer thru | or the adhesion layer etc. can be mentioned.
The film may have other layers as required, such as an antistatic layer, a hard coat layer, and an anchor layer.

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

The pressure-sensitive adhesive sheet adopts, for example, a method in which the resin composition is directly extruded and a method in which the resin composition is injected into a mold without using an adherend or a release film as described above. It can also be done.
Furthermore, the present pressure-sensitive adhesive sheet can also be made by directly filling the present resin composition between constituent members for an image display device, which is an adherend.

<Production method of this adhesive sheet>
An example of a method of producing the present adhesive sheet will be described.
First, the (meth) acrylic acid ester (co) polymer (a) and the visible light initiator (c), if necessary, a crosslinking agent (b), if necessary, a silane coupling agent (d), necessary Further, other materials may be respectively mixed in predetermined amounts to prepare the present resin composition.
The mixing method is not particularly limited, and the mixing order of the components is not particularly limited. In addition, a heat treatment step may be added at the time of production of the composition, and in this case, it is desirable to perform the heat treatment after mixing the respective components of the present resin composition in advance.
In addition, various mixed components may be concentrated and used as a master batch.

The apparatus for mixing is also not particularly limited, and for example, a universal kneader, a planetary mixer, a Banbury mixer, a kneader, a gate mixer, a pressure kneader, a three-roll, and a two-roll can be used. If necessary, a solvent may be used for mixing.
Moreover, this resin composition can be used as a non-solvent system which does not contain a solvent. By using as a solventless system, it is possible to provide an advantage that the solvent does not remain and the heat resistance and the light resistance are enhanced.
Also from this viewpoint, the present resin composition is preferably in a form containing (meth) acrylic acid ester (co) polymer (a), crosslinking agent (b) and visible light initiator (c).

This adhesive sheet can be manufactured by apply | coating (coating) this resin composition prepared as mentioned above on a base material sheet or a release sheet.
In addition, for example, the present pressure-sensitive adhesive sheet having a laminated structure is formed by applying (coating) the present resin composition onto a substrate sheet or a release sheet to form a first layer, and forming the first layer. The present resin composition is applied (coated) on a layer to form a second layer, or the first and second layers are formed in the same manner as described above. After that, the coated (coated) surfaces are bonded to each other, or the first resin layer and the second resin layer are simultaneously formed by multilayer coating or coextrusion molding of the present resin composition. can do.

It is employable without being specifically limited if it is a general coating method as said application (coating) method. For example, methods such as roll coating, die coating, gravure coating, comma coating, screen printing and the like can be mentioned.

Then, if necessary, the adhesive layer comprising the above-mentioned resin composition is irradiated with light to temporarily cure the adhesive layer (Y), leaving a room for photo-curing, and a gel of the adhesive layer (Y) The fraction may be 0 to 60%. However, the adhesive layer (Y) may not necessarily be temporarily cured by irradiating light, for example, the adhesive layer (Y) may be temporarily cured by heat or curing, and remains uncured It is also good.

<Application of this adhesive sheet>
This adhesive sheet can be suitably used in order to bond resin member (X) as mentioned above. Therefore, it can be provided as a pressure-sensitive adhesive sheet laminate (hereinafter referred to as "the present pressure-sensitive adhesive sheet laminate") having a configuration in which the resin member (X) having predetermined properties and the present pressure-sensitive adhesive sheet are laminated.

The pressure-sensitive adhesive sheet laminate is prepared, for example, using a resin composition containing a (meth) acrylic acid ester (co) polymer and a visible light initiator, and the pressure-sensitive adhesive sheet is It can produce by laminating | stacking to X). However, the method for producing the pressure-sensitive adhesive sheet laminate is not limited to the method.

(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 of the resin member (X) is 10% or less at 365 nm 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 ) Suppresses the photodegradation of the optical member (for example, an optical film such as a polarizing film or retardation film) located on the back side (opposite side to the visible side) and yellowness to the level required for the optical member (YI) can be reduced.
As such a resin member (X), a resin material is used as a main component, and what was adjusted to have the said light transmittance using an ultraviolet absorber can be mentioned.

As said resin material, the material which contains polycarbonate resin or acrylic resin as a main component resin, for example can be mentioned.
Under the present circumstances, "main component resin" means resin with most mass content among resin which comprises resin member (X).

The pressure-sensitive adhesive sheet also forms, for example, a photocurable pressure-sensitive adhesive sheet laminate by bonding the resin member (X) and the image display panel (P) via the pressure-sensitive adhesive sheet, and the resin member (X) side The adhesive layer (Y) is photocured by irradiating the adhesive sheet through the resin member (X) with light from which the integrated light quantity at 405 nm is 3000 (mJ / cm ² ), gel before and after photocuring The image display panel laminate can be manufactured by aggregating with a fractional difference of 10% or more.

The pressure-sensitive adhesive sheet laminate can be laminated, for example, with the image display panel (P) to produce an image display panel laminate.
Specifically, the image display panel laminate having a configuration in which the present pressure sensitive adhesive sheet laminate and the image display panel (P) are bonded together is, for example, the resin member (X) and the image display panel via the present pressure sensitive adhesive sheet. After laminating (P), light having a wavelength of 405 nm is irradiated from the outside of the resin member (X) through the resin member (X) to fully cure the adhesive layer (Y) of the present adhesive sheet By bonding the resin member (X) and the image display panel (P), an image display panel laminate can be manufactured.
The method for laminating the resin member (X) and the image display panel (P) via the pressure-sensitive adhesive sheet is not particularly limited, and either the resin member (X) or the image display panel (P) is used. After laminating with the adhesive sheet, the other may be laminated with the present adhesive sheet, or the resin member (X) and the image display panel (P) may be laminated with the present adhesive sheet at the same time.

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

In the pressure-sensitive adhesive sheet, as described above, the pressure-sensitive adhesive layer (Y) in the state where the object is stuck, that is, the pressure-sensitive adhesive layer (Y) after light (book) curing is the present resin composition from the viewpoint of antifoaming reliability. It is particularly preferable to have a cross-linked structure by
In particular, as described above, the pressure-sensitive 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) Co) providing a chemical bond by a compound having a polymer (a) and a functional group (ii) that reacts with the functional group (i), or an alkylene oxide unmodified trifunctional or higher polyfunctional (meth) compound It is particularly preferable to form using acrylate and to have a crosslinked structure resulting from these.

<< Description of words etc. >>
In the present invention, the term "film" is intended to include "sheet", and the term "sheet" is intended to include "film".
Moreover, when expressing as a "panel" like an image display panel, a protection panel, etc., a plate body, a sheet, and a film are included.

In the present invention, when describing as “X to Y” (X and Y are arbitrary numbers), “preferably greater than X” or “preferably Y” with the meaning of “X or more and Y or less” unless otherwise stated. "Less than" is also included.
Moreover, when stated as "X or more" (X is an arbitrary number), the meaning of "preferably greater than X" is included unless otherwise stated, and "Y or less" (Y is an arbitrary number) In the case where not particularly mentioned, the meaning of "preferably smaller than Y" is also included.

This will be described in more detail in the following examples. However, the present invention is not limited to the examples described below.

Examples and Comparative Examples
Materials used in Examples and Comparative Examples will be described.

Example 1
(Photo-curable adhesive sheet Y)
(Meth) acrylic acid ester (co) polymer: 13.5 parts by mass of a macromonomer having a terminal functional group of methacryloyl group (number average molecular weight of 3000) consisting of isobornyl methacrylate: methyl methacrylate = 1: 1, An acrylic graft copolymer (mass average molecular weight: 160,000) was prepared by random copolymerization of 43.7 parts by mass of lauryl acrylate, 40 parts by mass of 2-ethylhexyl acrylate, and 2.8 parts by mass of acrylamide.
90 g of propoxylated pentaerythritol triacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., NK ester ATM-4 PL) per 1 kg of this acrylic graft copolymer, and a mixture containing a cleavable visible light initiator as a visible light initiator 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, oligo (2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) propanone), 2,4,6-trimethyl A photocurable composition was obtained by adding 15 g of a mixture of benzophenone and 4-methylbenzophenone (Esacure KTO 46, manufactured by Lamberti) and mixing uniformly.
Next, the photocurable composition is formed into a sheet having a thickness of 150 μm on a polyethylene terephthalate film (Mitsubishi resin, Diafoil MRV, thickness 100 μm) whose surface has been subjected to peeling treatment, A polyethylene terephthalate film (Mitsubishi resin, Diafoil MRQ, thickness 75 μm) whose surface has been peeled off was coated to prepare a photocurable adhesive sheet Y1 with a release film.
In addition, photocurable adhesive sheet Y1 was an adhesive sheet provided with the photocurability hardened | cured by irradiating light.

(Resin member X)
A polycarbonate-based resin plate (Iupiron sheet MR58, manufactured by Mitsubishi Gas Chemical Co., Ltd., made by Mitsubishi Gas Chemical Co., Ltd.) as a resin member (X), having a thickness of 1.0 mm (used in bonding configuration P) and 1.5 mm (pasted) The thing of combined structure Q and bonding structure R was used.
Both of the thicknesses were 0% light transmittance at 365 nm and 83% light transmittance at 405 nm.

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

Example 2
The kind of cross-linking agent of the photocurable pressure-sensitive adhesive sheet Y was changed to pentaerythritol triacrylate (NK ester ATMM3 manufactured by Shin-Nakamura Chemical Co., Ltd.), and the number of blending parts was changed to 70 g with respect to 1 kg of acrylic graft copolymer In the same manner as in Example 1, photocurable pressure-sensitive adhesive sheets Y2 and X / Y2 laminates were obtained.
In addition, photocurable adhesive sheet Y2 was an adhesive sheet provided with the photocurability hardened | cured by irradiating 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) of which the terminal functional group is a methacryloyl group consisting of isobornyl methacrylate: methyl methacrylate = 1: 1. A hydroxy group formed by random copolymerization of 12.7 parts by mass, 41.1 parts by mass of lauryl acrylate, 37.6 parts by mass of 2-ethylhexyl acrylate, 2.6 parts by mass of acrylamide and 6 parts by mass of 4-hydroxybutyl acrylate Activity energy of a carbon-carbon double bond obtained by subjecting 6.5 parts by mass of 2-isocyanatoethyl methacrylate to an addition reaction with 100 parts by mass of an acrylic graft copolymer (mass average molecular weight: 160,000) The same as Example 1 except that it was changed to a (meth) acrylic copolymer having a linearly crosslinkable structural moiety. To obtain a photo-curable adhesive sheet Y3 and X / Y3 laminate. In addition, photocurable adhesive sheet Y3 was an adhesive sheet provided with the photocurability hardened | cured by irradiating light.

Example 4
As the photocurable pressure-sensitive adhesive sheet, phenylglylic acid acid methyl ester (Irgacure MBF, manufactured by BASF), which is a hydrogen abstraction type visible light initiator, is used as a visible light initiator, and the accumulated light amount at 405 nm is 100 (in advance) Photocurable pressure-sensitive adhesive sheets Y4 and X / Y4 laminates are obtained in the same manner as in Example 1 except that light is irradiated and primary curing (crosslinking) is performed so as to be mJ / cm ² ). The
In addition, photocurable adhesive sheet Y4 was an adhesive sheet provided with the photocurability hardened | cured by irradiating light.

[Example 5]
(Meth) acrylic acid ester (co) polymer: 13.5 parts by mass of a macromonomer having a terminal functional group of methacryloyl group (number average molecular weight of 3000) consisting of isobornyl methacrylate: methyl methacrylate = 1: 1, An acrylic graft copolymer (mass average molecular weight: 260,000) formed by random copolymerization of 73.7 parts by mass of 2-ethylhexyl acrylate, 2.8 parts by mass of acrylamide and 10 parts by mass of methyl acrylate is used as a crosslinking agent Light in the same manner as in Example 1 except that the type of the ester was changed to pentaerythritol triacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., NK ester ATMM 3 L) and the number of blending parts was changed to 70 g to 1 kg of acrylic graft copolymer. A curable pressure-sensitive adhesive sheet Y5 and an X / Y5 laminate were obtained.
In addition, photocurable adhesive sheet Y5 was an adhesive sheet provided with the photocurability hardened | cured by irradiating light.

[Example 6]
Photocurable pressure-sensitive adhesive sheets Y6 and X / Y6 laminates were obtained in the same manner as Example 5, except that the blending amount of the crosslinking agent was changed to 120 g with respect to 1 kg of the acrylic graft copolymer.
In addition, photocurable adhesive sheet Y6 was an adhesive sheet provided with the photocurability hardened | cured by irradiating light.

[Example 7]
The type of crosslinking agent is 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 Photocurable pressure-sensitive adhesive sheets Y7 and X / Y7 laminates were obtained in the same manner as in Example 5, except that 90 g and 30 g were used in combination.
In addition, photocurable adhesive sheet Y7 was an adhesive sheet provided with the photocurability hardened | cured by irradiating light.

[Example 8]
The type of crosslinking agent is 120 g each of pentaerythritol triacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., NK ester ATMM 3L) and dipentaerythritol tetraacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., NK ester A 9570W) per 1 kg of acrylic graft copolymer The photocurable pressure-sensitive adhesive sheets Y8 and X / Y8 laminates were obtained in the same manner as in Example 5 except that 40 g of them were used in combination.
In addition, photocurable adhesive sheet Y8 was an adhesive sheet provided with the photocurability hardened | cured by irradiating light.

[Example 9]
As a (meth) acrylic copolymer, 13.5 parts by mass of a macromonomer having a terminal functional group of methacryloyl group (number average molecular weight of 3,000) consisting of isobornyl methacrylate: methyl methacrylate = 1: 1, 2 As a crosslinking agent to 1 kg of an acrylic graft copolymer (mass average molecular weight: 260,000) formed by random copolymerization of 73.7 parts by mass of ethylhexyl acrylate, 2.8 parts by mass of acrylamide and 10 parts by mass of methyl acrylate Using 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) in amounts of 75 g and 25 g, respectively 2,4,6, which are mixtures containing a type visible light initiator, Mixture of trimethylbenzoyl-diphenyl-phosphine oxide, oligo (2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) propanone), 2,4,6-trimethylbenzophenone and 4-methylbenzophenone 15 g of (Esacure KTO 46, manufactured by Lamberti) was added, and 2 g of 3-glycidoxypropyltrimethoxysilane (KBM 403 manufactured by Shin-Etsu Silicon Co., Ltd.) was uniformly mixed as a silane coupling agent to obtain a photocurable composition.
Next, the photocurable composition is formed into a sheet on a polyethylene terephthalate film (diafoil MRV, manufactured by Mitsubishi Chemical Corporation, Diafoil MRV, thickness 100 μm) whose surface is subjected to peeling treatment so as to have a thickness of 25 μm. Then, a polyethylene terephthalate film (Diafoil MRQ, manufactured by Mitsubishi Chemical Corp., thickness: 75 μm) whose surface has been subjected to peeling treatment is coated, and a pressure-sensitive adhesive sheet Y9a for front and back layers with a release film is produced.

As a (meth) acrylic copolymer, pentaerythritol triacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., NK ester ATMM 3 L) as a crosslinking agent to 1 kg of an acrylic graft copolymer similar to that used in the adhesive sheet Y9a for front and back layers 30 g, a mixture containing a cleavable visible light initiator as visible light initiator, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, oligo (2-hydroxy-2-methyl-1- (4-) 15 g of a mixture of (1-methylvinyl) phenyl) propanone), 2,4,6-trimethyl benzophenone and 4-methyl benzophenone (Esacure KTO 46, manufactured by Lamberti) is added and uniformly mixed to obtain a photocurable composition. The
Next, the photocurable composition is formed into a sheet on a polyethylene terephthalate film (diafoil MRV, manufactured by Mitsubishi Chemical Corporation, Diafoil MRV, thickness 100 μm) whose surface has been subjected to peeling treatment to a thickness of 100 μm. Then, a polyethylene terephthalate film (Diafoil MRQ, manufactured by Mitsubishi Chemical Corporation, Diafoil MRQ, 75 μm thick) whose surface has been subjected to release treatment is coated to prepare a pressure-sensitive adhesive sheet Y9b for an intermediate layer with a release film.

While peeling off PET films on both sides of the intermediate layer pressure-sensitive adhesive sheet Y9b sequentially, the adhesive surfaces of the two front and back layer adhesive sheets Y9a are sequentially laminated on both surfaces of the intermediate layer pressure-sensitive adhesive sheet Y9b Photocurable pressure-sensitive adhesive sheet Y9 which is a laminate of two types and three layers (total thickness 150 μm) consisting of pressure-sensitive adhesive sheet Y9a) / (pressure-sensitive adhesive sheet Y9b for middle layer) / (pressure-sensitive adhesive sheet Y9a for front and back layers) In the same manner, an X / Y9 laminate was obtained.

[Example 10]
The (meth) acrylic copolymer used for the intermediate layer pressure-sensitive adhesive sheet Y9b is a macromonomer having a terminal functional group of methacryloyl group (number average molecular weight 3, 3, consisting of isobornyl methacrylate: methyl methacrylate = 1: 1). Acrylic graft copolymer (mass average) formed by random copolymerization of 13.5 parts by mass of 000), 43.7 parts by mass of lauryl acrylate, 40 parts by mass of 2-ethylhexyl acrylate, and 2.8 parts by mass of acrylamide Molecular weight: same as Example 9 except that the pressure-sensitive adhesive sheet Y10b for intermediate layer is changed to 160,000, and (pressure-sensitive adhesive sheet Y9a for front and back layers) / (pressure-sensitive adhesive sheet Y10b for middle layer) / (for front and back layers Obtain a photocurable adhesive sheet Y10 and an X / Y10 laminate which is a laminate of two types and three layers (total thickness 150 μm) consisting of the adhesive sheet Y9a). .
In addition, photocurable adhesive sheet Y10 was an adhesive sheet provided with the photocurability hardened | cured by irradiating light.

Comparative Example 1
Example except that a mixture of 2,4,6-trimethyl benzophenone and 4-methyl benzophenone (manufactured by Lamberti, Esacure TZT), which is a hydrogen extraction initiator, is used as a photo-curing adhesive sheet as a photocurable adhesive sheet. In the same manner as in No. 1, photocurable pressure-sensitive adhesive sheets Y11 and X / Y11 laminates were obtained.

Comparative Example 2
As a photocurable pressure-sensitive adhesive sheet, 1- [4- (4-benzoylphenylsulfanyl) phenyl] -2-methyl-2- (4-methylphenylsulfonyl) propane, which is a hydrogen extraction 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 (manufactured by Lamberti, Esacure 1001 M) was used.

Comparative Example 3
A photocurable adhesive sheet Y13 and an X / Y13 laminate are prepared in the same manner as in Example 1 except that a commercially available transparent adhesive sheet for non-curable optical having no photocurable property is used as the photocurable adhesive sheet. I got

Comparative Example 4
Example 1 is the same as Example 1 except that a polycarbonate-based resin plate (thickness 1.0 mm, light transmittance 45% at 365 nm, light transmittance 91% at 405 nm) is used as the resin member X Similarly, photocurable pressure-sensitive adhesive sheets Y14 and X / Y14 laminates were obtained.

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

(1) Dynamic storage modulus (G ')
For each of 150 μm photocurable adhesive sheets Y1 to Y14 (without release film) obtained in Examples and Comparative Examples, eight sheets are stacked to 1200 μm, and a dynamic viscoelasticity measuring device rheometer (Eiko Seiki Co., Ltd.) Adhesive jig: It measured on conditions of (PHI) 25 mm parallel plate, distortion: 0.5%, frequency 1 Hz, temperature rising rate: 3 degrees C / min.

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

(3) Gel fraction With respect to each of the photocurable adhesive sheets Y1 to Y14 (without release film) obtained in Examples and Comparative Examples, a bag is formed of SUS mesh (# 200) whose mass (X) is measured in advance. The bag is folded and closed, and after measuring the mass (Y) of the packet, it is immersed in 100 ml of ethyl acetate and stored in the dark at 23 ° C. for 24 hours, and then the packet is taken out at 70 ° C. The ethyl acetate adhering was heated by heating for 5 hours to evaporate, the mass (Z) of the dried package was measured, and the determined mass was substituted into the following equation to determine the gel fraction X1.
Gel fraction (%) = [(Z-X) / (Y-X)] × 100

Moreover, about each of X / Y1-Y14 laminated body obtained by the Example and the comparative example, the integrated light quantity in 405 nm is 3000 (mJ / cm < ² >) using a high pressure mercury lamp from the resin member (X) side. After light was irradiated so as to become, a sample was collected from the adhesive layer portion on the surface of the photocurable adhesive sheet on the resin member (X) side, and the gel fraction X2 was determined by the same method as described above. Then, X2-X1 was calculated.

(4) Step absorbency Print 22 to 24 μm thick on the rim (3 mm on the long side and 15 mm on the short side) of the glass of 58 mm × 110 mm × thickness 0.8 mm, and the center recess is 52 mm × 80 mm A printed stepped glass plate was prepared.
With respect to each of the photocurable adhesive sheets Y1 to Y14 with release films obtained in Examples and Comparative Examples, one release film is peeled off, and the entire surface of soda lime glass (54 mm × 82 mm × 0.5 mm thickness) is obtained. After roll bonding, the remaining release film is peeled off, and a pressure-sensitive adhesive sheet is applied to the frame-like printing step of the printing step-adjusting glass plate using a vacuum press (temperature 25 ° C., press) The pressure was 0.13 MPa and an evaluation sample was prepared.
After subjecting the evaluation sample to autoclave treatment under the conditions of 60 ° C., 0.2 MPa, and 20 minutes, the pass / fail was determined based on the following evaluation criteria.
○ (good): no microbubbles are observed at all around the step difference × (poor): microbubbles are seen around the step difference

(5) Yellowness (YI)
In each of the X / Y1 to Y14 laminates obtained in Examples and Comparative Examples, the integrated light quantity at 405 nm is 3000 (mJ / cm ² ) using a high-pressure mercury lamp from the resin member (X) side I was irradiated with light.
With integrated light quantity at 405 nm, it is an ultraviolet integrated light quantity meter "UIT-250" (manufactured by Ushio Electric Co., Ltd.) and a light receiver "UVD-C 405" (manufactured by Ushio Electric Co., Ltd.). With integrated quantity of light which penetrates resin member (X) and is irradiated to photocurable pressure sensitive adhesive sheet (Y1-Y14) which installed and measured actinometer on the side opposite to the side irradiated with high pressure mercury lamp is there.
After this, using a spectrocolorimeter (Suga Test Instruments Co., Ltd.) “SC-T”, the yellowness (YI) of the X / Y1 to Y14 laminate is measured based on JIS K 7103, and the following evaluation criteria Pass / fail was judged.
○ (good): YI is less than 2 × (poor): YI is 2 or more

(6) UV resistance (ΔYI)
For the X / Y1 to Y14 laminates obtained in Examples and Comparative Examples, light was applied from the resin member (X) side so that the integrated light quantity at 405 nm would be 3000 (mJ / cm ² ) using a high pressure mercury lamp. Irradiated.
With integrated light quantity at 405 nm, it is an ultraviolet integrated light quantity meter "UIT-250" (manufactured by Ushio Electric Co., Ltd.) and a light receiver "UVD-C 405" (manufactured by Ushio Electric Co., Ltd.). With integrated quantity of light which penetrates resin member (X) and is irradiated to photocurable pressure sensitive adhesive sheet (Y1-Y14) which installed and measured actinometer on the side opposite to the side irradiated with high pressure mercury lamp is there.
Thereafter, using a UVB fluorescent lamp (G15T8E manufactured by Sankyo Electric Co., Ltd., irradiance 70 μW / cm ² ), an irradiation test at a distance of 20 cm for 72 hours was performed.
Based on the variation ΔYI of the degree of yellowness (YI) of the X / Y1 to Y14 laminates before and after irradiation, acceptance / rejection was determined according to the following evaluation criteria.
○ (good): ΔYI is less than 0.2 × (poor): ΔYI is 0.2 or more

(7) Foaming resistance reliability With respect to each of the X / Y laminates obtained in Examples and Comparative Examples, the other release film remaining on the Y surface side is peeled off, and the following three members are hand roller It adhered in each case, and the foaming resistance reliability at the time of pasting was evaluated, respectively.
Moreover, the X / Y laminated body was cut and used for the size of each member.
Specific bonding configurations are: X / Y laminate / member P (bonding configuration P), X / Y laminate / member Q (bonding configuration Q), and X / Y laminate / member R (bonding configuration) R) three types.
Member P: soda lime glass 54 mm × 82 mm × thickness 0.55 mm
Member Q: Soda lime glass 100 mm x 180 mm x thickness 0.55 mm
Member R PET film 100mm x 180mm x thickness 100μm

Moreover, with respect to the member P (pasting structure P), an autocreping process is performed on the conditions of temperature 60 degreeC, atmospheric pressure 0.2MPa, and 30 minutes, and affixing is performed, and members Q and R (pasting structure Q And R) were subjected to an auto-crepe treatment under conditions of a temperature of 80 ° C. and an atmospheric pressure of 0.2 MPa for 30 minutes to carry out final adhesion.

After the finishing and sticking, light is irradiated from the resin member (X) side using a high pressure mercury lamp so that the integrated light quantity at 405 nm becomes 3000 (mJ / cm ² ), and a foam resistance evaluation sample is produced. did.
The evaluation sample was exposed to an environment of 85 ° C. under an 85% RH environment for 24 hours, and those with no appearance defects such as foaming or peeling were evaluated as “good (good)”, those with foaming or peeling observed. It was judged as "x (poor)".
Moreover, the thing in which appearance defects, such as foaming and peeling, were not recognized by bonding structure P or Q (one surface glass member) and bonding structure R (double-sided resin member) was made into "very good (very good)", and bonding structure P Those with no appearance defects such as foaming or peeling in any of Q, R, and "R" are regarded as "good", and those in which foaming and peeling were observed in all of the bonding configurations P, Q and R It was comprehensively judged as x (poor).

(8) Haze after long-term storage (indicator of compatibility with crosslinking agent)
About each of the photocurable adhesive sheets Y obtained in Examples and Comparative Examples, after two months or more have passed from the preparation of the sheet, the two adhesive surfaces on which the release film of the adhesive sheet Y is peeled off and exposed are two sheets. It was pasted so as to be sandwiched by soda lime glass (thickness 0.55 mm) and irradiated with light using a high pressure mercury lamp so that the integrated light quantity at 405 nm would be 3000 (mJ / cm ² ), and then the haze value was measured. .
The measurement of the haze value was performed according to JIS K7136 using a haze meter (manufactured by Nippon Denshoku Kogyo Co., Ltd., NDH 5000).
Those with a haze value of less than 0.5 are "good", those with a haze value of 0.5 or more and less than 1.0 are "satisfactory", those with a 1.0 or more value are "x" It was judged as (poor).

(9) Tg after light curing
With respect to each of the 150 μm photocurable 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 would be 3000 (mJ / cm ² ) Then, eight photocurable adhesive sheets Y1 to Y14 are respectively stacked to 1200 μm, and an adhesive jig: φ 25 mm parallel, using a dynamic viscoelasticity measuring apparatus rheometer ("MARS" manufactured by Eko Seiki Co., Ltd.) It measured on conditions of plate, distortion: 0.5%, frequency 1 Hz, temperature rising rate: 3 ° C./min, and measured the temperature at which the obtained value of Tan δ becomes a peak as Tg.

(10) Viscosity For each of 150 μm photocurable pressure-sensitive adhesive sheets Y1 to Y14 (without release film) obtained in Examples and Comparative Examples, eight sheets are stacked to 1200 μm, and a dynamic viscoelasticity measuring device rheometer ( Adhesive jig: 精 25 mm parallel plate, strain: 0.5%, frequency: 1 Hz, temperature rising rate: 3 ° C./min, at 70 ° C. and 100 ° C., respectively, using Eko Seiki Co., Ltd. “MARS”) The complex viscosity of the pressure-sensitive adhesive sheet before light curing was measured.

(11) Storage Performance A laminate is prepared by sandwiching the photocurable adhesive sheets Y1 to Y14 cut into a 50 mm x 50 mm square between two 100 mm thick PET films 100 mm x 100 mm, at 23 ° C and 50%. After leaving for 300 hours under the environment of (1), visual observation was made to see if the adhesive was sticking out of the laminate.
The manufactured laminate was visually observed, and those in which the adhesive entirely leaked out were “poor”, those in which the adhesive only protruded at the corners were “Δ (satisfactory)”, and the adhesive did not protrude The item was judged as "good".

<Discussion>
The photocurable adhesive sheet laminate (X / Y1 to Y10 laminate) of the resin member (X) / photocurable adhesive sheet (Y1 to Y10) of Examples 1 to 10 has a wavelength from the resin member (X) side When light is irradiated so that the accumulated 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 is increased by 10% or more Since the dynamic storage elastic modulus (G ') maintained high temperature cohesion of 0.7 × 10 ⁴ Pa or more at 120 ° C. and 1 Hz, good anti-foaming reliability was obtained. In particular, when the touch sensor is a glass sensor, good foam resistance reliability is obtained.
Above all, in Examples 3, 7, 9, and 10, since the dynamic storage elastic modulus (G ') maintained high temperature cohesive force of 2.0 × 10 ⁴ Pa or more at 120 ° C. and 1 Hz, the touch sensor Favorable anti-foaming reliability was obtained even in the test assumed for the case of a film sensor.

In addition, in the test in which the touch sensor was assumed to be a film sensor, good resistance to foaming was obtained in Example 8. However, in the test in which the touch sensor was assumed to be a glass sensor, peeling of the glass was observed. Arose. It is considered that this is because the dynamic storage elastic modulus (G ') became too high at 120 ° C. and 1 Hz, and the tack and adhesion performance decreased.
In Example 2, since the content of the hydrophilic monomer constituting the (meth) acrylic acid ester (co) polymer (a) is 10 parts by mass or less, the phase separation proceeds during long-term storage, The haze after long-term storage was "satisfactory".
The step absorbability is good in any of the first to tenth embodiments, and it is considered that the cover member having the print step can withstand practical use depending on the type of the touch sensor.

In Examples 4, 9 and 10, since the viscosity (70 ° C.) was as high as 1.5 kPa · s or more, no sticking of the glue was observed even after long-term storage, and the storage properties were excellent.

In Comparative Examples 1 and 2, the light transmittance (%) at a wavelength of 390 nm of the photocurable pressure-sensitive adhesive sheets Y11 and Y12 is as high as 90% or more, and the integrated light amount at a wavelength of 405 nm is 3,000 (from the resin member (X) side). The adhesive layer (Y) can not be sufficiently cured because the progress of the excitation and curing (crosslinking) reaction by light absorption of the photoinitiator when light is irradiated to become mJ / cm ² ) is not sufficient, and the foaming resistance Air bubbles were generated during the reliability test.

In Comparative Example 3, the gel fraction of the photocurable pressure-sensitive adhesive sheet Y13 is as high as 88%, and the dynamic storage elastic modulus (G ′) (25 ° C.) is as high as 1.1 × 10 ⁵ Pa. Air bubbles formed.
In Comparative Example 4, since the resin member (X) did not contain an ultraviolet light absorber, and the light transmittance at a wavelength of 365 nm was as high as 45%, yellowing in the UV reliability test progressed.

Claims

A photocurable pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer (Y) having all the following characteristics (1) to (3).
(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.
The photocurable adhesive according to claim 1, wherein the photocurable property in the above (3) is a photocurable property that increases by 10% or more as a difference in gel fraction when irradiated with light having a wavelength of 405 nm. Sheet.
When irradiated with light having a cumulative light quantity of 3000 (mJ / cm 2 ) at a wavelength of 405 nm, the gel fraction before light irradiation (gel fraction before light irradiation X1) and the gel fraction after light irradiation (“light irradiation” The light curing property is such that the difference between it and the after gel fraction X2 (gel fraction after light irradiation X2-gel fraction before light irradiation X1) is 10% or more. Photocurable adhesive sheet.
The photocurable pressure-sensitive adhesive sheet according to any one of claims 1 to 3, wherein the pressure-sensitive adhesive layer (Y) contains a (meth) acrylic acid ester (co) polymer and a visible light initiator.
The photocurable pressure-sensitive adhesive sheet according to any one of claims 1 to 4, wherein the pressure-sensitive adhesive layer (Y) contains a silane coupling agent.
The (meth) acrylic ester (co) polymer is selected from 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. The photocurable pressure-sensitive adhesive sheet according to claim 4 or 5, wherein a chemical bond is formed by the combination of any of the functional groups.
The photocurable adhesive sheet of Claim 4 or 5 whose said (meth) acrylic acid ester (co) polymer is a graft copolymer provided with the macromonomer as a branch component.
The photocurable pressure-sensitive adhesive sheet according to any one of claims 4 to 7, wherein the visible light initiator is a hydrogen abstraction type visible light initiator.
The hydrogen abstraction type visible light initiators include phenylglyoxylic acid methyl ester, oxy-phenyl-acetic acid 2- [2-oxo-2-phenyl-acetoxy-ethoxy] ethyl ester and oxy-phenyl-acetic acid The photocurable pressure-sensitive adhesive sheet according to claim 8, which is any one or two selected from the group consisting of a mixture of 2- [2-hydroxy-ethoxy] ethyl esters.
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 a copolymerization component. The photocurable pressure-sensitive adhesive sheet according to any one of claims 4 to 9, which is a copolymer.
The photocurable pressure-sensitive adhesive sheet according to any one of claims 1 to 10, wherein the pressure-sensitive adhesive layer (Y) contains a crosslinking agent or is formed using a crosslinking agent.
The photocurable pressure-sensitive adhesive sheet according to claim 11, wherein the crosslinking agent is an alkylene oxide unmodified trifunctional or higher polyfunctional (meth) acrylate.
The photocurable pressure-sensitive adhesive sheet according to any one of claims 4 to 12, wherein the (meth) acrylic acid ester (co) polymer has an active energy ray-crosslinkable structural site.
The photocurable pressure-sensitive adhesive sheet according to any one of claims 1 to 13, wherein the storage elastic modulus (G ') is 0.9 × 10 5 Pa or less at a temperature of 25 ° C. and a frequency of 1 Hz.
The storage elastic modulus (G ′) of the pressure-sensitive adhesive layer (Y) after irradiation with light having an integrated light quantity 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 photocurable pressure-sensitive adhesive sheet according to any one of claims 1 to 14, which has a pressure of 10 4 Pa or more.
The storage elastic modulus (G ′) of the pressure-sensitive adhesive layer (Y) after irradiation with light having an integrated light quantity 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 photocurable pressure-sensitive adhesive sheet according to any one of claims 1 to 14, which has a pressure of 10 4 Pa or more.
The photocurable pressure-sensitive adhesive sheet according to any one of claims 1 to 16, wherein the pressure-sensitive adhesive layer (Y) has a hot-melt property which softens or flows when heated.
A pressure-sensitive adhesive sheet for use in bonding a resin member (X) having 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 according to any one of claims 1 to 17.
The photocurable pressure-sensitive adhesive sheet according to any one of claims 1 to 17, and a resin member (X) having 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 adhesive sheet laminated body provided with the structure formed by laminating and.
The photocurable pressure-sensitive adhesive sheet has a single layer or multilayer structure of two or more layers, and the pressure-sensitive adhesive layer (Y) on the surface of the single-layer or multilayer resin member (X) has a gel fraction ("gel before light irradiation Fraction X1) of 0 to 60%, and when irradiated with light having a wavelength of 405 nm from the outside of the resin member (X) through the resin member (X), The photocurable pressure-sensitive adhesive sheet laminate according to claim 19, characterized by having a photocurability that increases by 10% or more as a difference.
The pressure-sensitive adhesive layer (Y) of the photocurable pressure-sensitive adhesive sheet has a cumulative light quantity of 3000 (mJ / cm 2 ) at a wavelength of 405 nm from the outside of the resin member (X) through the resin member (X) Between the gel fraction before light irradiation (gel fraction before light irradiation X1) and the gel fraction after light irradiation (referred to as "gel fraction after light irradiation X2") (gel after light irradiation) 21. The photo-curable pressure-sensitive adhesive sheet laminate according to claim 19 or 20, which has a photo-curing property in which the fraction X2-gel fraction before light irradiation X1) is 10% or more.
The photocurable pressure-sensitive adhesive sheet laminate according to any one of claims 19 to 21, wherein the resin member (X) is a member containing a polycarbonate resin or an acrylic resin as a main component resin.
When light having an accumulated light quantity of 3000 (mJ / cm 2 ) at 405 nm is irradiated from the outside of the resin member (X) through the resin member (X), adhesion in the photocurable pressure-sensitive adhesive sheet after light irradiation The photocurable adhesive sheet laminate according to any one of claims 19 to 22, wherein the storage elastic modulus (G ') of the layer (Y) is 0.7 x 10 4 Pa or more at a temperature of 120 ° C and a frequency of 1 Hz. body.
When light having an accumulated light quantity of 3000 (mJ / cm 2 ) at 405 nm is irradiated from the outside of the resin member (X) through the resin member (X), adhesion in the photocurable pressure-sensitive adhesive sheet after light irradiation The light according to any of claims 19-23, wherein the storage elastic modulus (G ') of the layer (Y) is 2.0 × 10 4 Pa or more at a temperature of 120 ° C. and a frequency of 1 Hz. Curable adhesive sheet laminate.
A method of producing a photocurable pressure-sensitive adhesive sheet laminate according to any one of claims 19 to 24,
The said photocurable adhesive sheet is produced using the resin composition containing a (meth) acrylic acid ester (co) polymer and a visible light initiator, and the said photocurable adhesive sheet is laminated | stacked on the said resin member (X). The manufacturing method of the photocurable adhesive sheet laminated body characterized by doing.
The manufacturing method of the image display panel laminated body provided with the structure to which the photocurable adhesive sheet laminated body which has a photocurable adhesive sheet in any one of Claims 19-24, and the image display panel (P) were bonded. And
Laminating the resin member (X) and the image display panel (P) through the photocurable pressure-sensitive adhesive sheet,
The light of wavelength 405 nm is irradiated from the outside of the resin member (X) through the resin member (X) to cure the pressure-sensitive adhesive layer (Y) of the photocurable pressure-sensitive adhesive sheet, and the image display with the resin member (X) The manufacturing method of the image display panel laminated body characterized by bonding a panel (P).