KR102566966B1 - 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 - Google Patents

Abstract

It relates to a pressure-sensitive adhesive sheet used for bonding resin members, which has photocurability and is capable of achieving both step absorption and foam resistance reliability, and has a light transmittance of 10% or less at a wavelength of 365 nm, and A photocurable adhesive sheet used for bonding a resin member (X) having a light transmittance of 60% or more at a wavelength of 405 nm, having an adhesive layer (Y) having all the characteristics of (1) to (3) below A photocurable pressure-sensitive adhesive sheet characterized by the present invention is proposed. (1) The gel fraction 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 of light with a wavelength of 405 nm.

Description

Photocurable adhesive sheet, photocurable adhesive sheet laminate, method for manufacturing photocurable adhesive sheet laminate, and method for manufacturing image display panel laminate PRESSURE-SENSITIVE ADHESIVE SHEET LAMINATE, AND PRODUCTION METHOD FOR IMAGE DISPLAY PANEL LAMINATE}

The present invention is an adhesive sheet used for bonding resin members having ultraviolet ray-cutting properties that do not transmit ultraviolet rays, and is a photocurable adhesive sheet having the ability to be cured by irradiation with light (referred to as "photocurable property"). It relates to an adhesive sheet.

In recent years, in order to improve the visibility of image display devices, image display panels such as liquid crystal displays (LCDs), plasma displays (PDPs), electroluminescence displays (ELDs), and protection disposed on the front side (visible side) thereof By filling the gap between the panel and the touch panel member with an adhesive, reflection of incident light or outgoing light from the display image at the air layer interface is suppressed.

As a method for filling the voids between the constituent members for an image display device with an adhesive, a method is known in which a liquid adhesive resin composition containing an ultraviolet curable resin is filled in the voids and then cured by irradiation with ultraviolet rays (patented patent). Literature 1).

In addition, a method of filling voids between constituent members for an image display device using an adhesive sheet is also known. For example, Patent Document 2 discloses a method in which a pressure-sensitive adhesive sheet primarily crosslinked by ultraviolet rays is bonded to a constituent member of an image display device, and then the pressure-sensitive adhesive sheet is irradiated with ultraviolet rays through the constituent member of the image display device to cause secondary curing. .

In Patent Document 3, when an image display device constituent member having a stepped portion on the bonding surface is bonded through a transparent double-sided adhesive sheet, it is possible to follow the stepped portion and fill every corner, and furthermore, in the adhesive sheet A new transparent double-sided adhesive sheet capable of mitigating the generated deformation and maintaining foam resistance under a high temperature or high humidity environment without impairing processability, comprising at least one (meth)acrylic acid ester (co)polymer; A UV polymerization initiator (A) having a molar extinction coefficient of 10 or more at a wavelength of 365 nm and a molar extinction coefficient of 0.1 or less at a wavelength of 405 nm and a visible light polymerization initiator (B) having a molar extinction coefficient of 10 or more at a wavelength of 405 nm are contained. , The value obtained by dividing the dynamic storage modulus (E') at 60°C obtained by the tensile method by the dynamic storage modulus (G') at 60°C obtained by the shear method (E'/G') is A transparent double-sided adhesive sheet in a B-stage state of 10 or more has been proposed.

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

In the case of attaching two image display device constituent members using the photocurable adhesive sheet as described above, after the primary attachment of the two image display device constituent members via the adhesive sheet, one image Ultraviolet rays are irradiated from the outside of the display device constituent member, and the pressure-sensitive adhesive sheet is cured with ultraviolet rays through the image display device constituent member to perform secondary adhesion.

According to such a method, primary bonding can be performed while filling the irregularities of the adhered surface, and furthermore, adhesion reliability can be further improved by finally curing with ultraviolet rays. It is possible to achieve both "level water absorption" when there are irregularities on the surface and "reliability of foaming resistance" after bonding.

For example, in a vehicle-mounted image display device or the like, a resin front panel is used to prevent glass from scattering, and a conductive member or a resin member such as a polarizing plate may be disposed inside the front panel. In this case, since it is necessary to prevent deterioration such as yellowing of the front panel or a conductive member disposed inside the front panel or a resin member such as a polarizing plate due to exposure to ultraviolet rays, an ultraviolet absorber is applied to the resin member on the side exposed to ultraviolet rays. It has been performed to have the ability to absorb ultraviolet rays by blending.

However, in this case, as described above, the pressure-sensitive adhesive sheet cannot be cured with ultraviolet light through the image display device constituent member by irradiating ultraviolet rays from the outside of the image display device constituent member.

For this reason, when attaching the resin front panel, it is unavoidable to use a non-photocurable adhesive sheet that is sufficiently cured to have foam resistance reliability and does not have photocurability.

However, such a non-photocurable pressure-sensitive adhesive sheet was not necessarily satisfactory in terms of level difference absorbency.

The present invention is a new adhesive that can be bonded to a resin member that does not transmit ultraviolet rays and has ultraviolet ray-cutting properties, and which can achieve both step absorption when there are irregularities on the adhered surface of the bonding member and foam resistance reliability after bonding. to provide sheets.

The present invention is a resin member having ultraviolet ray-cutting properties that does not transmit ultraviolet rays, 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) As a photocurable adhesive sheet used for bonding,

A photocurable adhesive sheet characterized by having an adhesive layer (Y) having all of the following characteristics (1) to (3) is proposed.

(1) The gel fraction (gel fraction X1 before light irradiation) is in the range of 0 to 60%.

(2) The light transmittance at a wavelength of 390 nm is 89% or less, and the light transmittance at a wavelength of 410 nm is 80% or more.

(3) It has photocurability that is cured by irradiation of light with a wavelength of 405 nm.

The present invention also has a configuration in which the photocurable adhesive sheet and the 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 are laminated. A photocurable pressure-sensitive adhesive sheet laminate is proposed.

Since the photocurable pressure-sensitive adhesive sheet proposed by the present invention has a gel fraction of 0 to 60% before photocuring, it is possible to obtain step absorption properties that fill in steps such as irregularities on the adhered surface, while having a light transmittance of 89% at a wavelength of 390 nm. % or less, and since it is provided with photocurability that is cured by irradiation of light with a wavelength of 405 nm, the resin member (X) to be bonded has a light transmittance of 10% or less at a wavelength of 365 nm, and at a wavelength of 405 nm Even if the light transmittance of is 60% or more, it can be cured by irradiation with light including a wavelength of 405 nm, and the cohesive force can be increased to obtain the foam resistance reliability after bonding.

In addition, since the photocurable adhesive sheet proposed by the present invention has a light transmittance of 80% or more at a wavelength of 410 nm, it is said that a sufficiently low yellowness (YI) required for bonding optical members requiring transparency can be achieved. effect can be obtained.

The photocurable PSA sheet laminate proposed by the present invention can obtain level difference absorption as described above, and the adhesive layer (Y) of the photocurable PSA sheet is formed from the outside of the resin member (X) ( When irradiated with light having a wavelength of 405 nm through X), it has a photocurable property that increases by 10% or more as a difference in gel fraction. By irradiating with light of 405 nm, the adhesive layer (Y) can be cured, and the cohesive force can be increased to obtain the reliability of anti-foaming after bonding.

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

<<this adhesive sheet>>

The PSA sheet (referred to as "this PSA sheet") according to an example of the embodiment of the present invention is a photocurable PSA sheet having a PSA layer (Y) having predetermined characteristics.

This PSA sheet is a PSA sheet with photocurable properties 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 there is room for photocuring, or uncured (referred to as "uncured") that is not yet cured and has photocuring properties. referred to).

If the present PSA sheet is temporarily cured or uncured, the present PSA sheet can be photocured (also referred to as “final curing”) after bonding the present PSA sheet to an adherend, and as a result, cohesive force is increased and adhesion is achieved. You can raise your stamina.

Preferred embodiments of the PSA sheet having the above-described pre-cured or non-cured properties and a property capable of being fully cured, that is, photocurable property that is cured by irradiation with light having a wavelength of 405 nm, include the following (1) to The adhesive sheet which has the adhesive layer (Y) shown in (3) is mentioned.

(1) The adhesive layer (Y) is temporarily cured so that the gel fraction is 60% or less, and is an adhesive layer capable of final curing with the visible light initiator (c) by containing a visible light initiator (c) described below.

(2) The adhesive layer (Y) is temporarily cured so that the gel fraction is 60% or less with a visible light initiator (c-2) of a hydrogen extraction type among visible light initiators (c) described below, and the visible light initiator (c-2 ) is an adhesive layer capable of main curing.

(3) The adhesive layer (Y) is an adhesive layer that can be fully cured with the visible light initiator (c) by holding the sheet shape in an uncured state and containing the visible light initiator (c) described below.

As a method for forming the adhesive layer (Y) in the above (1), for example, a visible light initiator (c), a (meth)acrylic acid ester (co)polymer (a) having a functional group (i), and the functional group (i) A compound having a functional group (ii) that reacts with, and, if necessary, a crosslinking agent (b) such as a photopolymerizable compound (especially a polyfunctional monomer) having a carbon-carbon double bond, and, if necessary, a silane coupling agent A method of forming an adhesive layer (Y) by heating or curing a composition (an example of the present resin composition described later) containing (d) is exemplified.

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, thereby curing (crosslinking) and forming the adhesive layer (Y). is formed By forming the adhesive layer (Y) in this way, the visible light initiator (c) can exist in the adhesive layer (Y) while remaining active.

Examples of combinations 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. 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 preferred. More specifically, a case 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 is a particularly suitable example.

Moreover, the compound which has the said functional group (ii) may further have radically polymerizable functional groups, such as a (meth)acryloyl group. Accordingly, the photocuring (crosslinking) of the (meth)acrylic acid ester (co)polymer by the radical polymerizable functional group, specifically, the (meth)acrylic acid ester copolymer having an active energy ray crosslinkable structural moiety described below, is improved. The adhesive layer (Y) can be formed while holding. 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-acrylic acid ester) Royloxyethyl isocyanate, 2-methacryloyloxyethyl isocyanate, 1,1-(bisacryloyloxymethyl)ethyl isocyanate, etc.) are particularly preferable examples.

In this way, by using the crosslinking reaction between the (meth)acrylic acid ester (co)polymers by the radical polymerizable functional group, the cohesive force after photocuring (crosslinking) is easily increased efficiently without using the crosslinking agent (b), and the reliability is excellent. Since there are advantages, such as, etc., it is more preferable.

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

As a method for forming the adhesive layer (Y) in the above (2), for example, a method using a visible light initiator (c-2) of a hydrogen extraction type described below as the visible light initiator (c) is exemplified. Even if the hydrogen withdrawal type initiator is excited once, unreacted ones of the initiators return to the ground state, and thus can be used again as a visible light initiator. In this way, by using a visible light initiator of a hydrogen withdrawal type, visible light curing (crosslinking) property by the visible light initiator can be maintained even after temporary curing by visible light irradiation.

In addition, points other than the above and a preferable form of the visible light initiator (c-2) are described below.

As a method for forming the adhesive layer (Y) in the above (3), for example, a method using a macromonomer described below as a monomer component constituting the (meth)acrylic acid ester copolymer (a) is exemplified. More specifically, a method using a graft copolymer provided with a macromonomer as a branch component is exemplified. By using such a macromonomer, it is possible to maintain a state in which branch components are attracted to each other and physically crosslinked as a composition (an example of the present resin composition described later) at room temperature.

Therefore, the sheet shape can be maintained in an uncured (crosslinked) state, and the adhesive layer (Y) containing the visible light initiator (c) can be formed.

In addition, points other than the above and a preferred embodiment of the graft copolymer provided with a macromonomer as a branch component will be described below.

It is preferable to use this adhesive sheet for bonding the resin member (X) mentioned later.

This adhesive sheet may have a single-layer structure of the adhesive layer (Y) or a multilayer structure of two or more layers including the adhesive layer (Y). In addition, in the case of a multilayer, at least the outermost layer may be the adhesion layer (Y), and all the adhesion layers may be the adhesion layer (Y).

<Adhesive layer (Y)>

It is preferable that the said adhesive layer (Y) has all the characteristics of the following (1)-(3).

(1) The gel fraction in the normal state, that is, 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 of light with a wavelength of 405 nm.

If the adhesive layer (Y) has a hot melt property that softens or flows by heating, when there is a step difference such as unevenness on the adhered surface of the bonding member, the adhesive can be more easily filled to every corner of the step, , from the viewpoint of further increasing the level difference absorbency.

From such a viewpoint, it is preferable to set the adhesion layer (Y) as the adhesion layer (Y) of said (3).

(gel fraction)

The gel fraction (gel fraction X1 before light irradiation) of the adhesive layer (Y) is preferably in the range of 0 to 60%.

When the gel fraction of the adhesive layer (Y) is 60% or less, there are sufficiently many uncrosslinked components that can be cured by light irradiation (in a pre-cured state or an uncured state), and it is so soft and cured When doing this, it is preferable from the viewpoint that the "gel fraction after light irradiation X2-gel fraction before light irradiation X1" can be 10% or more.

From this point of view, the gel fraction of the adhesive layer (Y) is preferably in the range of 0 to 60%, more preferably 55% or less, and more preferably 50% or less.

In order to adjust the gel fraction (gel fraction X1 before light irradiation) of the adhesive layer (Y) within the above range, the residual catalyst must be sufficiently removed during polymerization of the present resin composition and processing of the adhesive sheet, which will be described later, or a polymerization inhibitor , by using an antioxidant, etc., to prevent unintended curing (crosslinking) reaction by heat, light, etc. What is necessary is just to make the integrated light quantity of irradiated light sufficiently small, and to make an uncrosslinked component sufficiently large. However, it is not limited to this method.

Further, the adhesive layer (Y) is preferably provided with photocurability that is cured by irradiation with light having a wavelength of 405 nm, and the degree of photocurability is, for example, the resin member (X) from the outside. When irradiated with light having a wavelength of 405 nm through (X), the difference in gel fraction is 10% or more, especially 15% or more, especially 20% or more, especially 30% or more, especially 50% or more. It is preferable to have photocurability.

In addition, “irradiation of light with a wavelength of 405 nm” means irradiation of light having a photosensitivity with a wavelength of 405 nm as a photosensitivity peak and a base extending to a wavelength range of 320 to 470 nm, measured using an ultraviolet photometer. means to do

Among them, the adhesive layer (Y) transmits light with a cumulative amount of light of 3000 (mJ/cm ² ) at a wavelength of 405 nm from the outside of the resin member (X) through the resin member (X), for example. When irradiated, the difference 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-gel before light irradiation) It is preferable to have a photocurable property in which the fraction 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 amount of light of 3000 (mJ/cm ² ) at a wavelength of 405 nm (“after light irradiation”) Gel fraction X2") is preferably provided with photocurability such that it becomes 50% or more.

When the difference in gel fraction of the adhesive layer (Y) before and after photocuring is 10% or more, it is preferable in view of high cohesion even in a harsh high temperature, high humidity environment, etc., and improving foaming resistance reliability.

Therefore, the difference in gel fraction of the adhesive layer (Y) before and after the light irradiation is preferably 10% or more, more preferably 15% or more, more preferably 20% or more, more preferably 30% or more, and more preferably 50% or more. .

In order to adjust the gel fraction difference of the adhesive layer (Y) before and after the light irradiation to be within the above range, absorption by the photoinitiator at a wavelength of 405 nm is sufficient. However, it is not limited to this method.

In addition, "accumulated light amount at a wavelength of 405 nm" is the total amount of irradiation energy received per unit area, and among the light irradiated by a high-pressure mercury lamp or the like, an ultraviolet ray integrated photometer "UIT-250" (manufactured by Ushio Electric Co., Ltd.) ) and a receiver "UVD-C405" (manufactured by Ushio Electric Co., Ltd.), indicating the total amount of light irradiation energy measured, and the photosensitization characteristics of the photoreceptor (with 405 nm as the photosensitization peak, up to a wavelength range of 320 to 470 nm) It refers to the integrated amount of light in the wavelength range according to the light sensitivity of which the base is widened). More specifically, it refers to the integrated amount of light obtained based on the method described in Examples.

(light transmittance)

It is preferable that the adhesive layer (Y) 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.

Regarding the adhesive formulation containing a photoinitiator having absorption in the ultraviolet to visible light region around a wavelength of 400 nm, the light absorption of the photoinitiator is large, and the lower the light transmittance at a wavelength of 390 nm derived from the absorption, the better the photosensitivity, and the curing proceeds. it becomes easier to become

On the other hand, when the light transmittance at a wavelength of 410 nm is not higher than a certain level, the adhesive layer (Y) is colored yellow and it becomes difficult to use it for an optical member.

As a criterion above, when the light transmittance at a wavelength of 390 nm is 89% or less, the adhesive layer (Y) is preferable because sufficient visible light curability can be ensured, and when the light transmittance at a wavelength of 410 nm is 80% or more, transparency It is preferable because it is possible to achieve a sufficiently low yellowness index (YI) required for bonding of this required optical member.

Therefore, the light transmittance of the adhesive layer (Y) at a wavelength of 390 nm is preferably 89% or less, more preferably 88% or less.

In addition, the light transmittance at a wavelength of 410 nm is preferably 80% or more, more preferably 85% or more, and more preferably 90% or more.

In order to set the light transmittance of the adhesive layer (Y) as described above, among initiators capable of absorbing visible light, the bottom of the absorption peak sufficiently reaches up to 390 nm, whereas the absorption peak becomes smaller at 410 nm. You can use what has . However, it is not limited to this method.

(storage modulus)

The storage 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 viscoelastic properties, the pressure-sensitive adhesive sheet can obtain particularly excellent step absorption properties for filling steps such as irregularities on the adherend surface.

From this point of view, the storage modulus (G') of the adhesive layer (Y) is preferably 0.9 × 10 ⁵ Pa or less, more preferably 0.8 × 10 ⁵ Pa or less at a temperature of 25 ° C and a frequency of 1 Hz.

The adhesive layer (Y) also has a storage modulus (G') after irradiation with light having a cumulative amount of light of 3000 (mJ/cm ² ) at a wavelength of 405 nm, 0.7×10 ⁴ Pa at a temperature of 120°C and a frequency of 1 Hz. It is preferable to be more than

When the storage modulus (G') of the adhesive layer (Y) after photocuring falls within the above range, when the laminate with the resin member (X) is subjected to a high-temperature test, a high-temperature, high-humidity test or the like, outgassing from the resin member (X) It is preferable from the viewpoint that the foaming of the adhesive layer (Y) can be suppressed by the component.

From this point of view, the storage modulus (G') of the adhesive layer (Y) after photocuring is preferably 0.7×10 ⁴ Pa or more at a temperature of 120° C. and a frequency of 1 Hz, and more preferably 1.0×10 ⁴ Pa or more. It is preferable, and among these, it is more preferable that it is 2.0×10 ⁴ Pa or more.

By the way, in an image display device having a touch panel function, as a touch sensor disposed on the back side of the front panel/adhesive layer, a glass sensor, a film sensor, a polarizing plate glass (on-cell type or in-cell type with a built-in sensor), etc. The usage is divided according to the design of the module, and the degree to which problems in the environmental test are likely to occur varies depending on the configuration of the sensor member.

As a result of the experimental examination in the present invention, when the adhesive layer (Y) is bonded and used in the configuration of the resin member (X) / adhesive layer (Y) / glass sensor, the storage elastic modulus of the adhesive layer (Y) (G ') is within the above range, while the resin member (X)/adhesive layer (Y)/film sensor is bonded and used, the film sensor is usually 100 μm or less thin and has low rigidity, Since 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 than in the case of the glass sensor in the wet heat environment test, and further high storage modulus (G') becomes necessary

Therefore, from this point of view, that is, the storage elastic modulus (G' ), that is, the preferred range of the storage modulus (G') of the adhesive layer (Y) when irradiated with light having a cumulative amount of light of 3000 (mJ/cm ² ) at a wavelength of 405 nm is 2.0 × 10 ⁴ Pa or more. , Among them, it is more preferably 5.0 × 10 ⁴ Pa or more, and among them, 8.0 × 10 ⁴ Pa or more is more preferred.

(Composition of adhesive layer (Y))

The adhesive layer (Y) is a (meth)acrylic acid ester (co)polymer (a) and a visible light initiator (c), if necessary, a further crosslinking agent (b), if necessary, a silane coupling agent (d), if necessary Accordingly, it can be formed into an adhesive composition (referred to as "the present resin composition") containing other materials.

[(meth)acrylic acid ester (co)polymer (a)]

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

In addition, "(meth)acryl" means acryl and methacryl, "(meth)acryloyl" means acryloyl and methacryloyl, and "(meth)acrylate" means acrylate and methacrylate respectively. "(Co)polymer" is meant to encompass polymers and copolymers. In addition, a "sheet" conceptually includes a sheet, a film, and a tape.

Examples of the (meth)acrylic acid ester (co)polymer (a) include a homopolymer of alkyl (meth)acrylate as well as a copolymer obtained by polymerizing a monomer component copolymerizable with this. For example, the copolymer obtained by polymerizing the monomer component copolymerizable with this other than the homopolymer of alkyl (meth)acrylate is mentioned.

More specifically, as the (meth)acrylic acid ester (co)polymer (a), an alkyl (meth)acrylate and a monomer component copolymerizable with this, for example, (a) a carboxyl group-containing monomer (hereinafter referred to as “copolymerizable monomer”) Also referred to as "A"), (b) hydroxyl group-containing monomer (hereinafter also referred to as "copolymerizable monomer B"), (c) amino group-containing monomer (hereinafter also referred to as "copolymerizable monomer C"), (d) epoxy group-containing Monomer (hereinafter also referred to as “copolymerizable monomer D”), (e) amide group-containing monomer (hereinafter also referred to as “copolymerizable monomer E”), (f) vinyl monomer (hereinafter also referred to as “copolymerizable monomer F”). ), (g) a (meth)acrylate monomer having 1 to 3 carbon atoms in the side chain (hereinafter also referred to as "copolymerizable monomer G") and (h) macromonomer (hereinafter also referred to as "copolymerizable monomer H") and copolymers with monomer components containing any one or more selected monomers.

As said alkyl (meth)acrylate, the C4-C18 linear or branched alkyl (meth)acrylate of a side chain is preferable.

Examples of the straight-chain 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 (meth)acrylate, pentyl (meth)acrylate, isopentyl (meth)acrylate, neopentyl (meth)acrylate, hexyl (meth)acrylate, cyclohexyl (meth)acrylate, heptyl (meth)acrylate Acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, t-butylcyclohexyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate 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, dicyclopentenyloxyethyl (meth)acrylate, and the like. You may use these 1 type or in combination of 2 or more types.

Among the above, as straight-chain or branched alkyl (meth)acrylates having 4 to 18 carbon atoms, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate and isobornyl ( It is particularly preferable to include any one or more of meth)acrylates.

Examples of the copolymerizable monomer A include (meth)acrylic acid, 2-(meth)acryloyloxyethylhexahydrophthalic acid, 2-(meth)acryloyloxypropylhexahydrophthalic acid, and 2-(meth)acryloyl. Iloxyethylphthalic acid, 2-(meth)acryloyloxypropylphthalic acid, 2-(meth)acryloyloxyethylmaleic acid, 2-(meth)acryloyloxypropylmaleic acid, 2-(meth)acrylo yloxyethylsuccinic acid, 2-(meth)acryloyloxypropylsuccinic acid, crotonic acid, fumaric acid, maleic acid, and itaconic acid. These may combine 1 type(s) or 2 or more types.

Examples of the copolymerizable monomer B include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 2-hydroxybutyl (meth)acrylate. ) hydroxyalkyl (meth)acrylates such as acrylate. These may combine 1 type(s) or 2 or more types.

Examples of the copolymerizable monomer C include aminoalkyl (meth)acrylates such as aminomethyl (meth)acrylate, aminoethyl (meth)acrylate, aminopropyl (meth)acrylate, and aminoisopropyl (meth)acrylate. N,N-dialkylaminoalkyl (meth)acrylate, N-alkylaminoalkyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, N,N-dimethylaminopropyl (meth)acrylate, etc. ) acrylate. These may combine 1 type(s) or 2 or more types.

Examples of the copolymerizable monomer D include glycidyl (meth)acrylate, methyl glycidyl (meth)acrylate, 3,4-epoxycyclohexylmethyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate. ) Acrylate glycidyl ether is mentioned. These may combine 1 type(s) or 2 or more types.

Examples of the copolymerizable monomer E include (meth)acrylamide, N,N-dimethyl (meth)acrylamide, N-butyl (meth)acrylamide, N-methylol (meth)acrylamide, and N-methylol. Propane (meth)acrylamide, N-methoxymethyl (meth)acrylamide, N-butoxymethyl (meth)acrylamide, diacetone (meth)acrylamide, maleic acid amide, and maleimide. These may combine 1 type(s) or 2 or more types.

Examples of the copolymerizable monomer F include compounds having a vinyl group in the molecule. Examples of such compounds include (meth)acrylic acid alkyl esters having 1 to 12 carbon atoms in the alkyl group, functional monomers having functional groups such as hydroxyl groups, amide groups, and alkoxylalkyl groups in the molecule, and polyalkylene glycol di(metha)acrylates. ) 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 styrene. These may combine 1 type(s) or 2 or more types.

Moreover, among the above, it is preferable to select an alkyl (meth)acrylate and the said copolymerizable monomer F other than the said alkyl (meth)acrylate.

As said copolymerizable monomer G, methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, i-propyl (meth)acrylate etc. are mentioned, for example. These may combine 1 type(s) or 2 or more types.

Moreover, among the above, it is preferable to select an alkyl (meth)acrylate and the said copolymerizable monomer G other than the said alkyl (meth)acrylate.

The macromonomer as the copolymerizable monomer H is a polymeric monomer having a terminal functional group and a high molecular weight skeleton component, and is preferably a monomer having 20 or more carbon atoms in the side chain when a (meth)acrylic acid ester copolymer is formed by polymerization. .

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 into a graft copolymer. For example, a (meth)acrylic acid ester copolymer (a-1) composed of a graft copolymer provided with a macromonomer as a branch component can be used.

Therefore, the characteristics of the main chain and side chain of the graft copolymer can be changed by the selection of the copolymerizable monomer H and the other monomers and the blending ratio.

The skeleton component of the macromonomer is preferably composed of an acrylic acid ester polymer or a vinyl polymer. Examples thereof include straight-chain or branched alkyl (meth)acrylates having 4 to 18 carbon atoms in the side chain, copolymerizable monomer A, copolymerizable monomer B, copolymerizable monomer G, and the like. or may be used in combination of two or more.

Especially, it is preferable that the stem component of the (meth)acrylic acid ester copolymer (a-1) contains a hydrophobic (meth)acrylic acid ester and a hydrophilic (meth)acrylic acid ester as structural units.

As the above hydrophobic (meth)acrylic acid esters, alkyl esters having no polar group (except for methyl acrylate) are preferable, for example, n-butyl (meth) acrylate and isobutyl (meth) acrylate , sec-butyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, isopentyl (meth)acrylate, neopentyl (meth)acrylate, hexyl (meth)acrylate, cyclo Hexyl(meth)acrylate, heptyl(meth)acrylate, 2-ethylhexylacrylate, n-octylacrylate, isooctylacrylate, nonyl(meth)acrylate, isononyl(meth)acrylate, t-butyl Cyclohexyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, lauryl (meth)acrylate, cetyl (meth)acrylate, stearyl (meth)acrylate ) Acrylate, isostearyl (meth) acrylate, behenyl (meth) acrylate, isobornyl (meth) acrylate, cyclohexyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, Methyl methacrylate is mentioned.

Moreover, as a hydrophobic vinyl monomer, vinyl acetate, styrene, t-butyl styrene, (alpha)-methylstyrene, vinyl toluene, an alkyl vinyl monomer etc. are mentioned, for example.

On the other hand, as the above hydrophilic (meth)acrylate monomer, methyl acrylate or an ester having a polar group is preferable, and examples thereof include methyl acrylate, (meth)acrylic acid, tetrahydrofurfuryl (meth)acrylate, and hydroxy Hydroxyl group-containing (meth)acrylates such as oxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, and glycerol (meth)acrylate, (meth)acrylic acid, 2- (meth)acryloyloxyethylhexahydrophthalic acid, 2-(meth)acryloyloxypropylhexahydrophthalic acid, 2-(meth)acryloyloxyethylphthalic acid, 2-(meth)acryloyloxypropylphthalic acid, 2-(meth)acryloyloxyethylmaleic acid, 2-(meth)acryloyloxypropylmaleic acid, 2-(meth)acryloyloxyethylsuccinic acid, 2-(meth)acryloyloxypropylsuccinic acid, Carboxyl group-containing monomers such as crotonic acid, fumaric acid, maleic acid, itaconic acid, monomethyl maleate and monomethyl itaconate, acid anhydride group-containing monomers such as maleic anhydride and itaconic anhydride, glycidyl (meth)acrylate, α -Epoxy group-containing monomers such as glycidyl ethyl acrylate and 3,4-epoxybutyl (meth)acrylate, alkoxypolyalkylene glycol (meth)acrylates such as methoxypolyethylene glycol (meth)acrylate, and N,N-dimethyl Acrylamide, hydroxyethyl acrylamide, etc. are mentioned.

The macromonomer as the copolymerizable monomer H preferably has 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 radical polymerizable group copolymerizable with another monomer is preferable. One or two or more radical polymerizable groups may be contained, and among these, one is particularly preferred.

Even when the said macromonomer has a functional group, it may contain 1 or 2 or more functional groups, and it is especially preferable that it is 1 among them.

In addition, either one or both of the radical polymerizable group and the functional group may be contained. In the case of containing both a radical polymerizable group and a functional group, two or more functional groups or radical polymerizable groups other than either functional groups to be added with polymer units composed of other monomers or radical polymerizable groups to be copolymerized with other monomers may be used.

Examples of the terminal functional group of the macromonomer include radical polymerization groups such as methacryloyl group, acryloyl group, and vinyl group, as well as hydroxyl group, isocyanate group, epoxy group, carboxyl group, amino group, amide group, and thiol group. A functional group is mentioned.

Especially, what has a radical polymerizable group copolymerizable with other monomers is preferable. One or two or more radical polymerizable groups may be contained, and among these, one is particularly preferred. Even when the macromonomer has a functional group, one or two or more functional groups may be contained, and among these, one is particularly preferred.

In addition, either one or both of the radical polymerizable group and the functional group may be contained. In the case of containing both a radical polymerizable group and a functional group, two or more functional groups or radical polymerizable groups other than any of the functional groups to be added with polymer units composed of other monomers or radical polymerizable groups to be copolymerized with other monomers may be used.

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

It is preferable that the glass transition temperature (Tg) of the said macromonomer is higher than the glass transition temperature of the copolymer component which comprises the said (meth)acrylic acid ester (co)polymer (a-1).

Specifically, since the glass transition temperature (Tg) of the macromonomer affects the heat-melting temperature (hot melt temperature) of the present adhesive sheet, it is preferably 30°C to 120°C, especially 40°C or higher or 110°C. °C or lower, more preferably 50 °C or higher or 100 °C or lower.

When the macromonomer has such a glass transition temperature (Tg), by adjusting the molecular weight, excellent processability and storage stability can be maintained, and it can be adjusted to hot melt at around 50°C to 80°C.

The glass transition temperature of a macromonomer means the glass transition temperature of the said macromonomer itself, and can be measured with a differential scanning calorimeter (DSC).

In addition, in the room temperature state, the branch components are attracted to each other and can maintain a state in which physical crosslinking has been performed as an adhesive composition, and furthermore, in order to release the physical crosslinking and obtain fluidity by heating at an appropriate temperature, the macromonomer It is also preferable to adjust the molecular weight or content of .

From this point of view, the macromonomer is preferably contained in a proportion of 5% by mass to 30% by mass in the (meth)acrylic acid ester copolymer (a), especially 6% by mass or more or 25% by mass or less, especially 8% by mass. It is more preferable to contain in a ratio of 20% by mass or more or 20% by mass or less.

The number average molecular weight of the macromonomer is preferably 500 to 100,000, preferably less than 8000, more preferably 800 or more and less than 7500, and more preferably 1000 or more and less than 7000.

The (meth)acrylic acid ester (co)polymer (a) preferably has an active energy ray crosslinkable structural site.

The active energy ray crosslinkable structure means, for example, in the presence of a visible light initiator (c) described later, a part of the (meth)acrylic acid ester copolymer (a) or a part other than the (meth)acrylic acid ester copolymer (a) It is a structural site capable of forming a cross-linked structure by reacting with a curing component.

Examples of the active energy ray crosslinkable structural site include 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 and a vinyl group. .

Since the polymer chains of the (meth)acrylic acid ester (co)polymer (a) have an unsaturated double bond, even when a crosslinking agent is not contained, the polymer chains can directly polymerize with each other, and the storage modulus (G') is high. level can be raised.

In addition, in active energy ray irradiation, any light source containing light with a wavelength of 405 nm may be used, and visible light LED light sources, high-pressure mercury lamps, etc. can

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, a monomer having a functional group is previously added to the (meth)acrylic acid ester (co)polymer (a). After copolymerization, a compound having a carbon-carbon double bond, such as a monomer having a functional group capable of reacting with this functional group (for example, 2-isocyanatoethyl (meth)acrylate) and an unsaturated double bond, - It is only necessary to react while maintaining the curability of the carbon double bond.

Among them, the (meth)acrylic acid ester copolymer (a) is a (meth)acrylic acid ester monomer component containing 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. ) It is preferably an acrylic acid ester (co)polymer (a-2).

Examples of such a (meth)acrylic acid ester (co)polymer (a-2) include decyl (meth)acrylate (alkyl group having 10 carbon atoms), lauryl (meth)acrylate (carbon number 12), and tridecyl (metha)acrylate (carbon number 12). ) 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 independently or may use 2 or more types together.

In addition, among the linear (meth)acrylic acid alkyl ester monomers (a) having an alkyl group of 10 to 24 carbon atoms, it is preferable to use an alkyl methacrylate from the viewpoint of lowering the dielectric constant and lowering the glass transition temperature of the acrylic resin. , Particularly preferably, it has 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 straight-chain alkyl group having 10 to 24 carbon atoms is 50 to 94% by weight, preferably 60 to 83% by weight, particularly preferably 60 to 83% by weight with respect to the entire (co)polymerization component. Preferably it is 70 to 80% by weight. By setting it within the above range, there is no possibility of increasing the dielectric constant or deteriorating the thermal stability of the resin.

[Crosslinking agent (b)]

As the crosslinking agent (b), a crosslinking agent having at least double bond crosslinking is preferable. For example, at least one selected from a (meth)acryloyl group, an epoxy group, an isocyanate group, a carboxyl group, a hydroxyl group, a carbodiimide group, an oxazoline group, an aziridine group, a vinyl group, an amino group, an imino group, and an amide group. A crosslinking agent having a crosslinkable functional group is exemplified, and may be used alone or in combination of two or more.

In particular, by using two or more types of crosslinking agents in combination, a high storage elastic modulus (G') can be achieved compared to the case where each is used alone, even when the total compounding amount is the same.

Therefore, it is more preferable to use two or more types of crosslinking agents (b) in combination.

Moreover, the aspect in which the crosslinking agent (b) chemically bonded with the (meth)acrylic acid ester (co)polymer (a) is also included.

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 having two or more crosslinkable functional groups. Moreover, you may have 3 or more, 4 or more crosslinkable functional groups as needed.

Moreover, the said crosslinkable functional group may be protected with the protecting group which can deprotect.

Examples of the polyfunctional (meth)acrylate include 1,4-butanediol di(meth)acrylate, glycerin di(meth)acrylate, neopentyl glycol di(meth)acrylate, and glycerin glycidyl ether di( meth)acrylate, 1,6-hexanedioldi(meth)acrylate, 1,9-nonanedioldi(meth)acrylate, tricyclodecanedimethacrylate, tricyclodecanedimethanoldi(meth)acrylate , bisphenol A polyethoxydi(meth)acrylate, bisphenol A polypropoxydi(meth)acrylate, bisphenol F polyethoxydi(meth)acrylate, ethylene glycol di(meth)acrylate, neopentyl glycol di (meth)acrylate, trimethylolpropane 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, dipentaerythritol penta (meth)acrylate, tripentaerythritol hexa(meth)acrylate, tripentaerythritolpenta(meth)acrylate, hydroxypivalate neopentyl glycol di(meth)acrylate, ε- of hydroxypivalate neopentyl glycol Di(meth)acrylate of caprolactone adduct, trimethylolpropane tri(meth)acrylate, trimethylolpropanepolyethoxytri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, etc. In addition to functional (meth)acrylic monomers, polyfunctional (meth)acrylic oligomers such as polyester (meth)acrylates, epoxy (meth)acrylates, urethane (meth)acrylates, and polyether (meth)acrylates are exemplified. . You may use these 1 type or in combination of 2 or more types.

Among the polyfunctional (meth)acrylates described above, from the viewpoint of imparting high cohesive force, those having a structure having a short distance between crosslinking points in the formed crosslinked structure and high crosslinking density are preferred, for example, alkylene. Tri- or higher functional (meth)acrylates with unmodified oxide are preferred, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol hexa (meth)acrylate, dipentaerythritol penta(meth)acrylate, tripentaerythritol hexa(meth)acrylate, tripentaerythritol penta(meth)acrylate, trimethylolpropane tri(meth)acrylate, ditrimethylolpropane Polyfunctional (meth)acrylates (b-1) selected from the group consisting of tetra(meth)acrylates are preferred.

You may use the said polyfunctional (meth)acrylate (b-1) 1 type(s) or combining 2 or more types (as a mixture).

In addition, when using the said polyfunctional (meth)acrylate (b-1) as a crosslinking agent, the said (meth)acrylic acid ester (a) is a monomer component containing a hydrophilic monomer as a polar component from a compatible viewpoint. It is preferably a copolymer of

When the (meth)acrylic acid ester (a) contains a polar component, the compatibility with the polyfunctional (meth)acrylate (b-1) becomes good, it becomes easy to mix during mixing, and it remains uncrosslinked for a long time. There is no fear that phase separation at the time of storage becomes difficult to occur and the haze value rises.

Specifically, as the (meth)acrylic acid ester (co)polymer (a), the above-mentioned alkyl (meth)acrylate and a copolymerizable monomer copolymerizable with this are hydrophilic from the above-mentioned copolymerizable monomers A to G. It is preferable that the monomer is appropriately selected, and, among others, a copolymer with the above-described hydrophilic (meth)acrylic acid ester or a monomer component containing at least methyl (meth)acrylate selected from the copolymerizable monomers G.

Furthermore, the (meth)acrylic acid ester (co)polymer (a) contains at least methyl (meth)acrylate, and the total amount of hydrophilic monomers (selected from copolymerizable monomers A to G) is (meta) It is especially preferable that it is a copolymer of monomer components which accounts for 10 mass parts or more in the whole acrylic acid ester (co)polymer (a).

In addition, the (meth)acrylic acid ester (co)polymer (a-1) includes, as a skeleton component (stem component), the above-mentioned straight-chain or branched alkyl (meth)acrylate having 4 to 18 carbon atoms in the side chain; It is preferable that it is a copolymer of the monomer component containing the said hydrophilic monomer as a copolymerizable monomer copolymerizable with.

The content of the crosslinking agent (b) is 0.5 to 50 parts by mass, particularly 1 part by mass or more or 40 parts by mass or less, especially 5 parts by mass or more, based on 100 parts by mass of the (meth)acrylic acid ester (co)polymer (a). Or it is preferable that it is a ratio of 30 mass parts or less.

[Visible light initiator (c)]

Visible light initiator (c) generates radicals by irradiation of visible light, light rays having a wavelength of at least 390 nm, 405 nm and 410 nm, for example, light rays in the wavelength range of 380 nm to 700 nm, and generates (meta) It is preferably a visible light initiator serving as a starting point for the reaction of the acrylic acid ester (co)polymer (a).

However, the visible light initiator (c) may generate radicals only when irradiated with visible light, or may also generate radicals when irradiated with light rays in a wavelength range other than the visible light range.

The visible light initiator (c) preferably has an extinction coefficient of 10 mL/(g/cm) or more at a wavelength of 405 nm, particularly 15 mL/(g/cm) or more, particularly 25 mL/(g/cm) More than that is more preferable. When the extinction 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 extinction 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. Moreover, you may use together with the photoinitiator whose extinction coefficient in wavelength 405nm is less than 10mL/(g./cm).

Photoinitiators are broadly classified into two groups according to the radical generating mechanism: cleavage-type photoinitiators capable of generating radicals by cleavage and decomposition of single bonds of the photoinitiators themselves, and photoexcited initiators and hydrogen donors in the system to form an excitation complex. It is largely distinguished from the hydrogen withdrawal type photoinitiator capable of forming and transferring hydrogen from a hydrogen donor.

Among these, the cleavage type photoinitiator decomposes when generating radicals by light irradiation to become a separate compound, and once excited, it does not have a function as a reaction initiator. For this reason, since it does not remain as an active species in the adhesive after completion|finish of crosslinking reaction, and there is no possibility of causing unexpected photodegradation etc. to an adhesive, it is preferable.

In addition, regarding the coloration peculiar to the photoinitiator, conventionally, when a cleavage-type visible light initiator (c-1) that is cured by irradiation with visible light is added to the pressure-sensitive adhesive, there is a risk of coloration. Therefore, as the visible light initiator (c), it is preferable to appropriately select a reaction decomposition product that absorbs in the visible light region and loses color.

On the other hand, the hydrogen withdrawal type photoinitiator not only maintains its function as a reaction initiator even when irradiated with light multiple times, but also does not generate decomposition products like cleavage type photoinitiators during radical generation reaction by irradiation with active energy rays such as ultraviolet rays. , it is difficult to become a volatile component after completion of the reaction, and is useful in that damage to an adherend can be reduced.

Therefore, a hydrogen abstraction type visible light polymerization initiator (c-2) that initiates polymerization by being excited by visible light is particularly preferred.

Examples of the cleavage type visible light initiator (c-1) include 2,2-dimethoxy-1,2-diphenylethan-1-one, 1-hydroxycyclohexylphenylketone, and 2-hydroxy-2- Methyl-1-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 phenylglyoxylate, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butan-1-one, 2-methyl-1 -[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-(dimethylamino)-2-[(4-methylphenyl)methyl)-1-[4-(4-morpholino No) phenyl] -1-butanone, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, (2,4,6-trimethylbenzoyl ) ethoxyphenylphosphine oxide, derivatives thereof, and the like.

Among these, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, (2,4,6-trimethylbenzoyldiphenylphosphine oxide, Acylphosphine oxide photoinitiators such as -trimethylbenzoyl)ethoxyphenylphosphine oxide and bis(2,6-dimethoxybenzoyl)2,4,4-trimethylpentylphosphine oxide are preferred.

Examples of the hydrogen withdrawal type visible light initiator (c-2) include bis(2-phenyl-2-oxoacetic acid)oxybisethylene, phenylglyoxylic acid methyl ester, and oxy-phenyl-acetic acid 2-[2-oxo- A mixture of 2-phenyl-acetoxy-ethoxy] ethyl ester and oxy-phenyl-acetic acid 2-[2-hydroxy-ethoxy] ethyl ester, thioxanthone, 2-chlorothioxanthone, 3-methylthioxanthone xanthone, 2,4-dimethylthioxanthone, anthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 2-aminoanthraquinone, camphorquinone and derivatives thereof; and the like. .

Among these, 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-ethoxy ] It is preferable that it is any 1 type(s) or 2 types selected from the group which consists of mixtures of ethyl esters.

In addition, the visible light initiator (c) is not limited to the substances mentioned above. Any one of the above visible light initiators (c) or derivatives thereof may be used, or two or more may be used in combination.

In addition to the visible light initiator (c), one that generates radicals only by irradiation with other light rays such as ultraviolet rays may be mixed.

The content of the visible light initiator (c) is not particularly limited. (meth)acrylic acid ester (co)polymer (a) in the adhesive layer (Y) 0.1 to 10 parts by mass, particularly 0.5 parts by mass or more and 5 parts by mass or less, especially 1 part by mass or more or 3 parts by mass, based on 100 parts by mass It is preferable to contain in a ratio of parts or less.

By setting the content of the visible light initiator (c) within the above range, appropriate reaction sensitivity to visible light can be obtained.

[Silane coupling agent (d)]

A silane coupling agent (d) can improve adhesiveness, especially adhesiveness to a glass material.

Examples of the silane coupling agent include compounds having hydrolyzable functional groups such as alkoxy groups in addition to unsaturated groups such as vinyl, acryloxy, and methacryloxy groups, amino groups, and epoxy groups.

Specific examples of the silane coupling agent include N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane, and γ-aminopropyltriethoxy. Silane, (gamma)-glycidoxypropyl trimethoxysilane, (gamma)-methacryloxypropyl trimethoxysilane, etc. can be illustrated.

Especially, in the adhesive layer (Y), γ-glycidoxypropyltrimethoxysilane or γ-methacryloxypropyltrimethoxysilane from the viewpoint of good adhesiveness and little discoloration such as yellowing. can be preferably used.

The said silane coupling agent can be used individually by 1 type or in combination of 2 or more types.

The content of the silane coupling agent (d) is preferably 0.1 to 5 parts by mass, more preferably 0.2 parts by mass or more and 3.0 parts by mass or less with respect to 100 parts by mass of the adhesive layer (Y).

In addition, similarly to the silane coupling agent, coupling agents such as organic titanate compounds can be effectively utilized.

[other ingredients]

Examples of components other than the above included in the present resin composition forming the adhesive layer (Y) include a light stabilizer, an ultraviolet absorber, a metal deactivator, a metal corrosion inhibitor, an antiaging agent, an antistatic agent, a moisture absorbent, a foaming agent, and an antifoaming agent. , inorganic particles, viscosity modifiers, tackifying resins, photosensitizers, various additives such as fluorescent agents, reaction catalysts (tertiary amine compounds, quaternary ammonium compounds, tin laurylate compounds, etc.), and the like. .

In addition, you may contain the well-known component mix|blended with a normal adhesive composition suitably.

Moreover, you may use together two or more types of each component.

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

Examples of the ultraviolet absorber include benzotriazole-based ultraviolet absorbers, benzophenone-based ultraviolet absorbers, and triazine-based ultraviolet absorbers. Moreover, the said ultraviolet absorber may be used individually or in combination of 2 or more types.

Especially, as for the said ultraviolet absorber, a triazine type ultraviolet absorber is especially preferable from a viewpoint of transparency, ultraviolet absorbability, and compatibility.

[Preferred compositional aspect of the present resin composition]

As an example of a preferred resin composition forming the adhesive layer (Y), (meth)acrylic acid ester (co)polymer (a), the crosslinking agent (b), a visible light initiator (c), and, if necessary, a silane couple A composition containing a ring agent is exemplified.

Among these, as the visible light initiator (c), it is preferable to use a visible light initiator (c) having an extinction coefficient of 10 mL/(g·/cm) or more at a wavelength of 405 nm, and as the visible light initiator (c), the cleavage type It is particularly preferable to use a visible light initiator (c-1) and/or a hydrogen withdrawal type visible light initiator (c-2).

Among them, the (meth)acrylic acid ester (co)polymer (a) is a functional group 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. It is preferable that a chemical bond is formed by a combination of

In addition, the (meth)acrylic acid ester (co)polymer (a) is a copolymerization component comprising the above-described straight-chain or branched alkyl (meth)acrylate having 4 to 18 carbon atoms in the side chain and the hydrophilic (meth)acrylate. It is preferable that it is a copolymer containing as.

Furthermore, it is preferable that the crosslinking agent (b) is the above polyfunctional (meth)acrylate (b-1).

As an example of the present preferred resin composition for forming the adhesive layer (Y), the (meth)acrylic acid ester copolymer (a-1) composed of a graft copolymer having a macromonomer as a branch component, the crosslinking agent (b) and , a composition containing a visible light initiator (c) and, if necessary, a silane coupling agent.

Among these, as the visible light initiator (c), it is preferable to use a visible light initiator (c) having an extinction coefficient of 10 mL/(g/cm) or more at a wavelength of 405 nm, and further, as the visible light initiator (c), the cleavage type It is particularly preferable to use a visible light initiator (c-1) and/or a hydrogen withdrawal type visible light initiator (c-2).

Among them, the (meth)acrylic acid ester (co)polymer (a-1) comprises, as a backbone component (stem component), the aforementioned straight-chain or branched alkyl (meth)acrylate having 4 to 18 carbon atoms in the side chain; It is preferable that it is a copolymer containing the said hydrophilic (meth)acrylate as a copolymerization component.

Moreover, it is preferable that a crosslinking agent (b) is the said polyfunctional (meth)acrylate (b-1).

As yet another preferred example of the present resin composition forming the adhesive layer (Y), the above (meth)acrylic acid ester comprising a graft copolymer having a macromonomer as a branch component and having an active energy ray crosslinkable structural site. A composition containing the copolymer (a-1), the crosslinking agent (b), the visible light initiator (c), and, if necessary, a silane coupling agent is exemplified.

Among these, as the visible light initiator (c), it is preferable to use a visible light initiator (c) having an extinction coefficient of 10 mL/(g·/cm) or more at a wavelength of 405 nm, and as the visible light initiator (c), the cleavage type It is particularly preferable to use a visible light initiator (c-1) and/or a hydrogen withdrawal type visible light initiator (c-2).

Among them, the (meth)acrylic acid ester (co)polymer (a-1) comprises, as a backbone component (stem component), the aforementioned straight-chain or branched alkyl (meth)acrylate having 4 to 18 carbon atoms in the side chain; It is preferable that it is a copolymer containing the said hydrophilic (meth)acrylate as a copolymerization component.

Moreover, it is preferable that a crosslinking agent (b) is the said polyfunctional (meth)acrylate (b-1).

When the adhesive layer (Y) is formed using the present resin composition having the above composition, the adhesive layer (Y) containing the (meth)acrylic acid ester copolymer (a) or (a-1) as a base resin is at room temperature. can exhibit self-adhering properties while maintaining a sheet shape, and can fill every corner of the step of the adherend surface of the bonding member with an adhesive. In addition, with the visible light initiator (c), it can be photocured by irradiation with visible light, and the cohesive force can be increased by photocuring, and the foaming resistance reliability can be improved.

Further, by blending a silane coupling agent, adhesiveness, particularly adhesiveness to glass materials, can be further improved.

In addition, since the adhesive layer (Y) containing the (meth)acrylic acid ester copolymer (a-1) as a base resin has a hot melt property that melts or flows when heated, it can have a higher step water absorption property. there is.

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

When the present resin composition having the above composition is used, it is possible to form a temporarily cured or uncured adhesive layer (Y) in a state where there is room for photocuring, and then irradiated with visible light once or twice or more. It can be photocured by Therefore, for example, after attaching the PSA sheet to an adherend, the PSA sheet can be photocured ("final curing") by irradiation with visible light, and the cohesive force is increased by the final curing, thereby increasing the foam resistance reliability. .

In particular, for (meth)acrylic acid ester (co)polymers having difficulty in storage due to high fluidity at room temperature, even when a step of increasing storage stability by temporary curing is performed, curing is performed by a post-process of visible light curing after bonding. can proceed

Further, by blending a silane coupling agent, adhesiveness, particularly adhesiveness to glass materials, can be further improved.

(Laminate construction)

As described above, when the adhesive layer (Y) has a laminated structure, it is preferable from the viewpoint of foam resistance that the adhesive layer (Y) using the present resin composition is the front and back layers as the outermost layer.

At this time, it is preferable that it is 15 micrometers or more, and, as for the thickness of the adhesive layer (Y) as a front and back layer, it is more preferable that it is 20 micrometers or more. If the thickness of the adhesive layer (Y) is 15 μm or more, it is preferable in that there is little possibility of occurrence of problems such as foaming due to outgas pressure generated from the adherend member in the reliability test.

Moreover, from a viewpoint of combining storage stability, it may be preferable to further equip another layer with a higher viscosity than the said adhesive layer (Y).

That is, the adhesive layer (Y) formed using the graft copolymer having a macro monomer is in an uncrosslinked state before photocuring, and when a polyfunctional (meth)acrylate monomer is used, such a polyfunctional (meth)acrylate Due to the action of the late monomer component, the adhesive layer (Y) before photocuring may become a layer with a relatively low viscosity.

For this reason, in such a case, it is preferable to laminate another layer (Z) having a higher viscosity than the said adhesion layer (Y) on the said adhesion layer (Y).

For example, if it is a multilayer structure consisting of three layers of adhesive layer (Y)/layer (Z)/adhesive layer (Y), excellent storage stability can be provided.

From the standpoint of such storage stability, the viscosity of the other layer (Z) is preferably 1 to 10 kPa·s, and more preferably 1.5 to 5 kPa·s in a temperature range of 70°C to 100°C.

In addition, the said viscosity is a value measured according to the method described in the Example.

Further, in the case where the present adhesive sheet has a multilayer structure as described above, the glass transition temperature (Tg) of the present adhesive sheet after irradiation with 405 nm light is preferably less than 20°C, from the viewpoint of further providing shock absorption resistance. It is more preferably less than °C.

By having such a relatively low Tg, the pressure-sensitive adhesive sheet has improved low-temperature adhesive properties (low-temperature peel strength, etc.) and can have shock absorption resistance.

Therefore, from the viewpoint of shock absorption resistance, the Tg of the adhesive layer (Y) and the other layer to be laminated after irradiation with 405 nm light is preferably less than 15°C, particularly less than 10°C, particularly less than 5°C.

In addition, the said Tg is a value measured by the peak temperature of Tan-delta of dynamic viscoelasticity, and is a value measured according to the method described in the Example in detail.

<Adhesive sheet having release film>

This PSA sheet can also be made into a PSA sheet having a release film.

For example, a pressure-sensitive adhesive sheet having a release film may be obtained by forming a single or multi-layered adhesive layer in the form of a sheet on the release film.

As a material for such a release film, a known release film can be appropriately used.

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

In the case of laminating release films on both sides of the present adhesive sheet, one release film may have the same laminated structure or material as the other release film, or may have a different laminated constitution or material.

Moreover, even if it is the same thickness, a different thickness may be sufficient.

In addition, release films with different peel forces or release films with different thicknesses can be laminated on both sides of the present adhesive sheet.

It is preferable that the light transmittance of the light in wavelength 410nm or less of the said release film is 40% or less.

By laminating a release film having a light transmittance of 40% or less for light at a wavelength of 410 nm or less on at least one surface of the pressure-sensitive adhesive sheet, it is possible to effectively prevent photopolymerization from proceeding by irradiation with visible light.

From this point of view, the release film laminated on one or both sides of the pressure-sensitive adhesive sheet preferably has a light transmittance of 40% or less for light at a wavelength of 410 nm or less, especially 30% or less, and more preferably 20% or less among them. do.

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 an action of partially blocking transmission of visible light and ultraviolet light, for example, a polyester, polypropylene, or polyethylene cast A laminated film having an ultraviolet ray absorbing layer obtained by applying a non-adhesive resin having re-peelability to one side of a film or stretched film and applying a paint containing a ultraviolet ray absorber to the other side thereof. .

In addition, a polypropylene-based or polyethylene-based cast film or stretched film coated with a slightly adhesive resin having releasability in which an ultraviolet absorber is blended is applied.

Further, those in which a non-adhesive resin having re-peelability is applied to a cast film or stretched film made of a polyester, polypropylene, or polyethylene resin to which an ultraviolet absorber is blended are exemplified.

In addition, a multi-layer cast film or stretched film formed by molding a layer made of a resin containing no ultraviolet absorber on one side or both sides of a layer made of a polyester, polypropylene, or polyethylene resin in which an ultraviolet absorber is blended. What applied the non-adhesive resin which has re-peelability to one surface is 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 further peeling on the ultraviolet absorbing layer Those coated with a non-adhesive resin having properties are exemplified.

In addition, a paint containing an ultraviolet absorber is applied to one side of a cast film or stretched film made of polyester, polypropylene, or polyethylene resin to provide an ultraviolet ray absorbing layer, and the other side has re-peelability What applied the non-adhesive resin is mentioned.

Further, a resin film made of a polyester, polypropylene, or polyethylene resin coated with a releasable slightly adhesive resin on one side and a separately prepared resin film containing an ultraviolet absorber What was laminated|stacked through an adhesive layer or an adhesive layer, etc. are mentioned.

The said film may have other layers as needed, such as an antistatic layer, a hard coat layer, and an anchor layer.

The thickness of the release film is not particularly limited. Among these, it is preferable that it is 25 micrometers - 500 micrometers, especially from a viewpoint of processability and handling property, especially, it is more preferable that it is 38 micrometers or more and 250 micrometers or less, and among these, 50 micrometers or more and 200 micrometers or less.

In addition, the present adhesive sheet may employ, for example, a method of directly extruding the present resin composition or a method of molding by injecting the present resin composition into a mold, without using an adherend or a release film as described above.

Furthermore, it can also be set as the aspect of this adhesive sheet by directly filling the present resin composition between the structural members for image display apparatuses which are adherends.

<Method for producing this pressure-sensitive adhesive sheet>

An example of a method for manufacturing this pressure-sensitive adhesive sheet will be described.

First, a (meth)acrylic acid ester (co)polymer (a) and a visible light initiator (c), if necessary, a crosslinking agent (b), if necessary, a silane coupling agent (d), and if necessary, other What is necessary is just to prepare this resin composition by mixing each predetermined amount of materials.

The method of mixing these is not particularly limited, and the mixing order of each component is not particularly limited either. In addition, a heat treatment step may be incorporated at the time of composition production, and in this case, it is preferable to perform heat treatment after mixing each component of this resin composition beforehand.

Moreover, you may use what concentrated various mixed components and made into a master batch.

The equipment for mixing is not particularly limited either, and for example, a universal kneader, a planetary mixer, a banbari mixer, a kneader, a gate mixer, a pressure kneader, or a three-roll or two-roll machine can be used. You may mix using a solvent as needed.

In addition, this resin composition can be used as a non-solvent system containing no solvent. By using it as a non-solvent system, the advantage that a solvent does not remain and heat resistance and light resistance become high can be provided.

Also from this point of view, the present resin composition is preferably in a form containing a (meth)acrylic acid ester (co)polymer (a), a crosslinking agent (b), and a visible light initiator (c).

This adhesive sheet can be manufactured by apply|coating (coating) this resin composition prepared as mentioned above on a base sheet or a release sheet.

Further, for example, in the present PSA sheet having a laminated structure, the present resin composition is applied (coated) on a base sheet or a release sheet to form a first layer, and on the formed first layer A method of repeating application (coating) of the present resin composition and forming a second layer, or a method in which the first and second layers are formed in the same manner as above, and then each application ( Coating) It can be produced by a method of bonding surfaces together or a method of simultaneously forming a first layer and a second layer of the present resin composition by multilayer coating or co-extrusion molding.

As the above coating (coating) method, any general coating method is not particularly limited and can be employed. For example, methods such as roll coating, die coating, gravure coating, comma coating, and screen printing are exemplified.

Then, if necessary, the adhesive layer made of the present resin composition is irradiated with light, the adhesive layer (Y) is temporarily cured, leaving room for photocuring, so that the gel fraction of the adhesive layer (Y) is 0 to 60 You can do it in %. However, it is not always necessary to temporarily cure the adhesive layer (Y) by irradiation with light, and the adhesive layer (Y) may be temporarily cured by, for example, heat or curing, or may remain uncured.

<Use of this pressure-sensitive adhesive sheet>

As described above, this adhesive sheet can be suitably used in order to bond the resin member (X). Therefore, it can be provided as a PSA sheet laminate (referred to as "this PSA sheet laminate") having a configuration in which the resin member (X) having predetermined characteristics and the present PSA sheet are laminated.

The present PSA sheet laminate is prepared by using, for example, a resin composition containing a (meth)acrylic acid ester (co)polymer and a visible light initiator, and then attaching the PSA sheet to the resin member (X). It can be produced by layering. However, the manufacturing method of this PSA sheet laminate is not limited to this 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.

When the resin member (X) has a light transmittance of 10% or less at 365 nm and a light transmittance of 60% or more at 405 nm, transmission of ultraviolet rays is sufficiently blocked (cut), and the resin member (X) itself and suppressing photodeterioration of an optical member (for example, an optical film such as a polarizing film or retardation film) located on the back side (a side opposite to the viewing side), and also having a yellowness level ( YI) can be reduced.

As such a resin member (X), one containing a resin material as a main component and adjusted to have the light transmittance described above using an ultraviolet absorber is exemplified.

As said resin material, the material containing polycarbonate type resin or acrylic type resin as main component resin is mentioned, for example.

At this time, the "main component resin" means a resin having the largest content mass among the resins constituting the resin member (X).

In this PSA sheet, for example, the resin member (X) and the image display panel (P) are bonded together through the PSA sheet to form a photocurable PSA sheet laminate, and from the resin member (X) side, The adhesive layer (Y) is photocured by irradiating the present adhesive sheet with light having a cumulative light intensity of 3000 (mJ/cm ² ) at 405 nm through the resin member (X), thereby photocuring the difference in gel fraction before and after photocuring. can be aggregated at 10% or more to produce an image display panel laminate.

This PSA sheet laminate can be bonded to, for example, an image display panel P to produce an image display panel laminate.

Specifically, the image display panel laminate having a configuration in which the present adhesive sheet laminate and the image display panel P are bonded together, for example, the resin member X and the image display panel ( After P) is laminated, light of 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, and the resin member (X) is then fully cured. An image display panel laminate can be manufactured by bonding (X) and the image display panel (P) together.

The method of laminating the resin member (X) and the image display panel (P) through the present adhesive sheet is not particularly limited, and either the resin member (X) or the image display panel (P) is present on the adhesive sheet. After laminating with the present adhesive sheet, the other side may be laminated with the present adhesive sheet, or the resin member (X) and the image display panel (P) may be simultaneously laminated with the present adhesive sheet.

(Image display panel (P))

As the above image display panel (P), for example, a polarizing film or other optical film such as a retardation film, a liquid crystal material, and a backlight system (usually, the adhered surface of the present composition or adhesive article to the image display panel is It is an optical film), and there are STN, VA, IPS, and the like depending on the control method of the liquid crystal material, but any method may be used.

Further, the image display panel may be an in-cell type in which a touch panel function is incorporated into a TFT-LCD, or an on-cell type in which a touch panel function is incorporated between a glass substrate provided with a polarizing plate and a color filter.

In the present adhesive sheet, the adhesive layer (Y) in the state where the object is adhered as described above, that is, the adhesive layer (Y) after light (main) curing has a crosslinked structure by the present resin composition from the viewpoint of foam resistance reliability. It is particularly preferred to have.

In particular, as described above, for the adhesive layer (Y), a (meth)acrylic acid ester copolymer having an active energy ray-curable site is used, or a (meth)acrylic acid ester (co)polymer having a functional group (i) ( Formed by providing a chemical bond between a) and a compound having a functional group (ii) that reacts with the functional group (i), or using an alkylene oxide unmodified tri- or higher-functional polyfunctional (meth)acrylate, , those having a cross-linked structure resulting from these are particularly preferred.

<<Explanation of phrases, etc.>>

In the present invention, the term "film" includes "sheet", and the term "sheet" also includes "film".

In addition, when expressing a "panel" such as an image display panel, a protection panel, etc., it includes a plate body, a sheet, and a film.

In the present invention, when "X to Y" (where X and Y are arbitrary numbers) is described, "preferably greater than X" or "preferably greater than X" or Preferably smaller than Y" is also included.

In addition, when "X or more" (X is an arbitrary number) is described, "preferably greater than X" is included and "Y or less" (Y is an arbitrary number) unless otherwise specified. In one case, the meaning of "preferably smaller than Y" is also included unless otherwise specified.

Example

It will be described in more detail in Examples below. 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]

(Photocurable adhesive sheet Y)

As a (meth)acrylic acid ester (co)polymer, 13.5 parts by mass of a macromonomer (number average molecular weight: 3000) having a terminal functional group consisting of isobornyl methacrylate:methyl methacrylate = 1:1 and having a methacryloyl group; An acrylic graft copolymer (mass average molecular weight: 160,000) obtained by randomly copolymerizing 43.7 parts by mass of lauryl acrylate, 40 parts by mass of 2-ethylhexyl acrylate, and 2.8 parts by mass of acrylamide was prepared.

2, 4, which is a mixture containing 90 g of propoxylated pentaerythritol triacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., NK Ester ATM-4PL) as a crosslinking agent and a cleavage type visible light initiator as a visible light initiator with respect to 1 kg of this acrylic graft copolymer. 6-trimethylbenzoyl-diphenyl-phosphine oxide, oligo(2-hydroxy-2-methyl-1-(4-(1-methylvinyl)phenyl)propanone), 2,4,6-trimethylbenzophenone, 15 g of a mixture of 4-methylbenzophenone (Esacure KTO46 manufactured by Lamberti) was added and mixed uniformly to obtain a photocurable composition.

Subsequently, the photocurable composition was molded into a sheet to have a thickness of 150 μm on a polyethylene terephthalate film (Mitsubishi Resin, Diafoil MRV, thickness 100 μm) having a surface peeling treatment, and then the surface was subjected to a peeling treatment A polyethylene terephthalate film (made by Mitsubishi Resin, dia foil MRQ, thickness: 75 μm) was coated to prepare a photocurable adhesive sheet Y1 having a release film.

In addition, the photocurable PSA sheet Y1 was a photocurable PSA sheet that was cured by irradiation with light.

(Resin member X)

As the resin member (X), it is a polycarbonate-based resin plate (manufactured by Mitsubishi Gas Chemical Co., Ltd., Euphylon Sheet MR58) containing an ultraviolet absorber, and has a thickness of 1.0 mm (used in bonding configuration P) and 1.5 mm (bonding configuration Q and bonding configuration) used in R).

Both thicknesses were 0% in light transmittance at 365 nm and 83% in light transmittance at 405 nm.

(Photocurable PSA Sheet Laminate)

The release film on one side of the photocurable adhesive sheet Y1 having a release film is peeled off, and roll bonding is performed on one side of the polycarbonate plate (resin member X), and the resin member (X) / photocurable adhesive sheet Y1 A chemical conversion adhesive sheet laminate (also referred to as "X/Y1 laminate") was obtained.

[Example 2]

Examples except that the type of crosslinking 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 mixing parts was changed to 70 g per 1 kg of the acrylic graft copolymer. It carried out similarly to 1, and obtained photocurable adhesive sheet Y2 and X/Y2 laminated body.

In addition, the photocurable PSA sheet Y2 was a photocurable PSA sheet that was cured by irradiation with light.

[Example 3]

The composition of the (meth)acrylic copolymer of the photocurable pressure-sensitive adhesive sheet Y is a macromonomer (number average molecular weight: 3000) consisting of isobornyl methacrylate:methyl methacrylate = 1:1 and having a methacryloyl group as the terminal functional group. Hydroxy group-containing acrylic graft copolymer 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 (Mass average molecular weight: 160,000) Obtained by addition reaction of 6.5 parts by mass of 2-isocyanatoethyl methacrylate with respect to 100 parts by mass, having an active energy ray crosslinkable structural site of a carbon-carbon double bond (meta) Photocurable adhesive sheet Y3 and X/Y3 laminate were obtained in the same manner as in Example 1 except for changing to an acrylic copolymer. In addition, the photocurable PSA sheet Y3 was a PSA sheet having photocurability that is cured by irradiation with light.

[Example 4]

As the photocurable pressure-sensitive adhesive sheet, methyl phenylglyoxylate (manufactured by BASF, Irgacure MBF), which is a hydrogen withdrawal type visible light initiator, was used as a visible light initiator, and the integrated light amount at 405 nm was 100 (mJ/cm ² ) in advance. Photocurable pressure-sensitive adhesive sheets Y4 and X/Y4 laminates were obtained in the same manner as in Example 1, except that primary curing (crosslinking) was performed by irradiation with light as much as possible.

In addition, the photocurable PSA sheet Y4 was a photocurable PSA sheet that was cured by irradiation with light.

[Example 5]

As a (meth)acrylic acid ester (co)polymer, 13.5 parts by mass of a macromonomer (number average molecular weight: 3000) having a terminal functional group consisting of isobornyl methacrylate:methyl methacrylate = 1:1 and having a methacryloyl group; An acrylic graft copolymer (mass average molecular weight: 260,000) formed by randomly copolymerizing 73.7 parts by mass of 2-ethylhexyl acrylate, 2.8 parts by mass of acrylamide, and 10 parts by mass of methyl acrylate was used, and the type of crosslinking agent was pentaerythritol tri Photocurable adhesive sheets Y5 and X/ A Y5 laminate was obtained.

In addition, the photocurable PSA sheet Y5 was a photocurable PSA sheet that was cured by irradiation with light.

[Example 6]

Photocurable adhesive sheets Y6 and X/Y6 laminates were obtained in the same manner as in Example 5, except that the blending amount of the crosslinking agent was changed to 120 g per 1 kg of the acrylic graft copolymer.

In addition, the photocurable PSA sheet Y6 was a PSA sheet having photocurability that is cured by irradiation with light.

[Example 7]

The type of crosslinking agent was 90 g and 30 g of pentaerythritol triacrylate (Nakamura Chemical Co., Ltd., NK Ester ATMM3L) and dipentaerythritol tetraacrylate (Nakamura Chemical Co., Ltd., NK Ester A9570W), respectively, per 1 kg of the acrylic graft copolymer. Photocurable adhesive sheet Y7 and X/Y7 layered product were obtained in the same manner as in Example 5 except that they were used in combination.

In addition, the photocurable PSA sheet Y7 was a photocurable PSA sheet that was cured by irradiation with light.

[Example 8]

The type of crosslinking agent was 120 g and 40 g of pentaerythritol triacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., NK Ester ATMM3L) and dipentaerythritol tetraacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., NK Ester A9570W) based on 1 kg of the acrylic graft copolymer. Photocurable adhesive sheet Y8 and X/Y8 layered product were obtained in the same manner as in Example 5 except that they were used in combination.

In addition, the photocurable PSA sheet Y8 was a PSA sheet having photocurability that is cured by irradiation with light.

[Example 9]

As a (meth)acrylic copolymer, 13.5 parts by mass of a macromonomer (number average molecular weight: 3,000) in which the terminal functional group consists of isobornyl methacrylate:methyl methacrylate = 1:1 and has a methacryloyl group, 13.5 parts by mass, 2-ethyl Pentaerythritol triacrylate (Shin Nakamura Chemical company, NK Ester ATMM3L) and dipentaerythritol tetraacrylate (Shin Nakamura Chemical Co., Ltd., NK Ester A9570W) are used together in an amount of 75 g and 25 g, respectively, and a mixture containing a cleavage type 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 15 g of a mixture of benzophenone and 4-methylbenzophenone (Esacure KTO46 manufactured by Lamberti) was added, and 2 g of 3-glycidoxypropyltrimethoxysilane (KBM403 manufactured by Shin-Etsu Silicone Co., Ltd.) was uniformly mixed as a silane coupling agent to form a photocurable composition was obtained.

Subsequently, the photocurable composition was molded into a sheet to a thickness of 25 μm on a polyethylene terephthalate film (diafoil MRV, manufactured by Mitsubishi Chemical Corporation, thickness 100 μm) having a surface peeling treatment, and then the surface was subjected to a peeling treatment A polyethylene terephthalate film (diafoil MRQ, manufactured by Mitsubishi Chemical Corporation, thickness: 75 μm) was coated to prepare a pressure-sensitive adhesive sheet Y9a for front and back layers having a release film.

As a (meth)acrylic copolymer, 30 g of pentaerythritol triacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., NK Ester ATMM3L) as a crosslinking agent, cleavage type as a visible light initiator, per 1 kg of the acrylic graft copolymer similar to that used for the front and back layer adhesive sheet Y9a 2,4,6-Trimethylbenzoyl-diphenyl-phosphine oxide, oligo(2-hydroxy-2-methyl-1-(4-(1-methylvinyl)phenyl)propanone, mixture containing visible light initiator ), 2,4,6-trimethylbenzophenone, and 15 g of a mixture of 4-methylbenzophenone (Esacure KTO46 manufactured by Lamberti) were added and mixed uniformly to obtain a photocurable composition.

Next, the photocurable composition was molded into a sheet to a thickness of 100 μm on a polyethylene terephthalate film (dia foil MRV, manufactured by Mitsubishi Chemical Corporation, thickness 100 μm) having a surface peeling treatment, and then the surface was subjected to a peeling treatment A polyethylene terephthalate film (dia foil MRQ, manufactured by Mitsubishi Chemical Corporation, thickness: 75 µm) was coated to prepare an adhesive sheet Y9b for an intermediate layer having a release film.

The PET films on both sides of the PSA sheet Y9b for the middle layer are sequentially peeled and removed, and the adhesive faces of the two PSA sheets Y9a for the front and back layers are sequentially bonded to both surfaces of the PSA sheet Y9b for the middle layer (Adhesive sheet Y9a for the front and back layers) /(Adhesive Sheet Y9b for Middle Layer)/(Adhesive Sheet Y9a for Front and Back Layers) Photocurable PSA Sheet Y9, which is a laminate of 2 types and 3 layers (total thickness: 150 µm), and X/Y9 laminate in the same manner as in Example 1 got it

[Example 10]

The (meth)acrylic copolymer used for the pressure-sensitive adhesive sheet for intermediate layer Y9b is a macromonomer (number average molecular weight: 3,000) composed of isobornyl methacrylate:methyl methacrylate = 1:1 and having a methacryloyl group as the terminal functional group. 13.5 parts by mass, 43.7 parts by mass of lauryl acrylate, 40 parts by mass of 2-ethylhexyl acrylate, and 2.8 parts by mass of acrylamide were randomly copolymerized to form an acrylic graft copolymer (mass average molecular weight: 160,000). A laminate of two types and three layers consisting of (Adhesive Sheet Y9a for Front and Back Layers) / (Adhesive Sheet Y10b for Middle Layers) / (Adhesive Sheet Y9a for Front and Back Layers) in the same manner as in Example 9 except that PSA Sheet Y10b for Middle Layer was formed. (Total thickness: 150 μm) photocurable pressure-sensitive adhesive sheets Y10 and X/Y10 laminates were obtained.

In addition, the photocurable PSA sheet Y10 was a photocurable PSA sheet that was cured by irradiation with light.

[Comparative Example 1]

As the photocurable pressure-sensitive adhesive sheet, in the same manner as in Example 1, except that a mixture of 2,4,6-trimethylbenzophenone and 4-methylbenzophenone (Esacure TZT, manufactured by Lamberti), which is a hydrogen withdrawal type initiator, was used as the photoinitiator. , photocurable pressure-sensitive adhesive sheet Y11 and X/Y11 laminate were obtained.

[Comparative Example 2]

As a photocurable adhesive sheet, 1-[4-(4-benzoylphenylsulfanyl)phenyl]-2-methyl-2-(4-methylphenylsulfonyl)propan-1-one (Lamberti Photocurable adhesive sheet Y12 and X/Y12 laminate were obtained in the same manner as in Example 1 except that sacure1001M) manufactured by the company was used.

[Comparative Example 3]

Photocurable adhesive sheets Y13 and X/Y13 laminates were obtained in the same manner as in Example 1, except that a commercially available non-curable transparent adhesive sheet for optics was used as the photocurable adhesive sheet.

[Comparative Example 4]

As the resin member X, a polycarbonate-based resin plate (thickness: 1.0 mm, light transmittance at 365 nm: 45%, light transmittance at 405 nm: 91%) containing no ultraviolet absorber was used in the same manner as in Example 1. Thus, photocurable pressure-sensitive adhesive sheet Y14 and X/Y14 laminate were obtained.

<evaluation>

The method of evaluation displayed in this specification is demonstrated.

(1) Dynamic storage modulus (G')

For each of the 150 μm photocurable pressure-sensitive adhesive sheets Y1 to Y14 (without release film) obtained in Examples and Comparative Examples, 8 sheets were stacked to 1200 μm, and a dynamic viscoelasticity measuring device rheometer (“MARS manufactured by Eco Seiki Co., Ltd.) ") was used, and the measurement was performed under the conditions of an adhesive jig: 25 mm parallel plate, strain: 0.5%, frequency of 1 Hz, and temperature increase rate: 3°C/min.

(2) spectral transmittance

Regarding the resin member (X), the spectral transmittance (%T) at a wavelength of 300 nm to 800 nm was measured using a spectrophotometer (UV2000 manufactured by Shimadzu Corporation). This spectral transmittance was referred to as light transmittance.

(3) Gel fraction

Each of the photocurable adhesive sheets Y1 to Y14 (without release film) obtained in Examples and Comparative Examples was wrapped in a pouch shape with a SUS mesh (#200) whose mass (X) was measured in advance, and the mouth of the pouch was folded and closed. , After measuring the mass (Y) of this package, it was immersed in 100 ml of ethyl acetate and stored in the dark at 23 ° C for 24 hours, then the package was taken out and heated at 70 ° C for 4.5 hours to evaporate the adhering ethyl acetate. , The mass (Z) of the dried package was measured, and the obtained mass was substituted into the following formula to obtain the gel fraction X1.

Gel fraction (%) = [(Z-X)/(Y-X)] × 100

In addition, for each of the X/Y1 to Y14 laminates obtained in Examples and Comparative Examples, from the resin member (X) side, a high-pressure mercury lamp was used, and the integrated light amount at 405 nm was 3000 (mJ/cm ² ) After irradiation with light to achieve this, a sample was taken 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 in the same manner as described above. Then, X2-X1 was calculated.

(4) step absorption

22 to 24 μm thick printing was applied to the periphery of 58 mm × 110 mm × 0.8 mm thick glass (3 mm on the long side and 15 mm on the short side), and the recess in the center formed a printing step of 52 mm × 80 mm. Eggplant prepared a glass plate.

For each of the photocurable adhesive sheets Y1 to Y14 having a release film obtained in Examples and Comparative Examples, one release film was peeled off, and the entire surface of soda lime glass (54 mm × 82 mm × thickness 0.5 mm) was roll bonded. After that, the remaining release film is peeled off, and the pressure-sensitive adhesive sheet is applied to the photo frame-shaped printed step of the glass plate having the print step, and vacuum pressure is applied using a vacuum press (temperature: 25 ° C., press pressure: 0.13 MPa) to evaluate wrote a sample.

After the evaluation sample was autoclaved under conditions of 60°C, 0.2 MPa, and 20 min, pass/fail was judged according to the following evaluation criteria.

○ (good): No microbubbles were found around the steps.

× (poor): Micro bubbles were found around the steps

(5) Yellowness (YI)

For each of the X/Y1 to Y14 laminates obtained in Examples and Comparative Examples, from the resin member (X) side, a high-pressure mercury lamp was used so that the integrated light amount at 405 nm was 3000 (mJ/cm ² ). light was investigated.

The integrated light quantity at 405 nm is the high-pressure mercury of the resin member (X) using an ultraviolet integrating photometer "UIT-250" (manufactured by Ushio Electric Co., Ltd.) and a photoreceptor "UVD-C405" (manufactured by Ushio Electric Co., Ltd.) It is the integrated amount of light transmitted through the resin member (X) and irradiated to the photocurable adhesive sheets (Y1 to Y14), measured by installing a photometer on the surface opposite to the surface to be irradiated with the lamp.

After that, using a spectrophotometer (Suga Test Instruments Co., Ltd.) "SC-T", based on JIS K7103, the yellowness (YI) of the X / Y1 to Y14 laminate was measured, and passed according to the following evaluation criteria judged whether

○ (good): YI is less than 2

× (poor): YI is 2 or more

(6) UV resistance reliability (ΔYI)

For the X/Y1 to Y14 laminates obtained in Examples and Comparative Examples, light was emitted from the resin member (X) side using a high-pressure mercury lamp so that the integrated light amount at 405 nm was 3000 (mJ/cm ² ). investigated

The integrated light quantity at 405 nm is the high-pressure mercury of the resin member (X) using an ultraviolet integrating photometer "UIT-250" (manufactured by Ushio Electric Co., Ltd.) and a photoreceptor "UVD-C405" (manufactured by Ushio Electric Co., Ltd.) It is the integrated amount of light transmitted through the resin member (X) and irradiated to the photocurable adhesive sheets (Y1 to Y14), measured by installing a photometer on the surface opposite to the surface to be irradiated with the lamp.

Thereafter, an irradiation test was conducted at a distance of 20 cm and for 72 hr using a UVB fluorescent lamp (G15T8E manufactured by Sankyo Electric Co., Ltd., irradiance of 70 µW/cm ² ).

From the amount of change ΔYI in the yellowness (YI) of the X/Y1 to Y14 laminate before and after irradiation, acceptance was judged according to the following evaluation criteria.

○ (good): ΔYI is less than 0.2

× (poor): ΔYI is 0.2 or more

(7) Anti-foam reliability

For each of the X/Y laminates obtained in Examples and Comparative Examples, the other release film remaining on the Y surface side was peeled off, the following three types of members were attached to the exposed surface with a hand roller, and the inside when bonded Foaming reliability was evaluated, respectively.

In addition, the X/Y laminate was used after being cut to the size of each member.

There are three types of specific bonding configurations: 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). .

Member P: soda lime glass 54 mm × 82 mm × thickness 0.55 mm

Material Q: soda lime glass 100 mm × 180 mm × thickness 0.55 mm

Member R: PET film 100 mm × 180 mm × thickness 100 μm

In addition, for member P (bonding configuration P), autoclave treatment is performed under the conditions of a temperature of 60 ° C., atmospheric pressure of 0.2 MPa, and 30 minutes to perform finish bonding, and for members Q and R (bonding configuration Q and R), An autoclave treatment was performed under the conditions of a temperature of 80°C, an atmospheric pressure of 0.2 MPa, and 30 minutes to perform final adhesion.

After the above finish bonding, light was irradiated from the resin member (X) side using a high-pressure mercury lamp so that the integrated light amount at 405 nm was 3000 (mJ/cm ² ) to prepare foam resistance reliability evaluation samples.

The evaluation sample, 85 ℃, 85% R.H. It was exposed to the environment for 24 hr, and it was judged that "(circle) (good)" and those in which foaming and peeling were confirmed were "x (poor)" for appearance defects, such as foaming and peeling, not confirmed.

In addition, in the bonding configuration P or Q (one-sided glass member) and bonding configuration R (double-sided resin member), those in which no appearance defects such as foaming or peeling were confirmed were “◎ (very good)”, bonding configurations P, Q and R In any of them, those in which appearance defects such as foaming and peeling were confirmed were rated as "○ (good)", and those in which foaming and peeling were confirmed in all of the bonding configurations P, Q, and R were evaluated as "x (poor)".

(8) Haze after long-term storage (index of compatibility with crosslinking agent)

For each of the photocurable PSA sheet Y obtained in Examples and Comparative Examples, after two months or more have elapsed since the sheet was produced, the release film of the PSA sheet Y is peeled off and the exposed adhesive surfaces on both sides are coated with soda lime glass ( 0.55 mm in thickness), and irradiated with light so that the cumulative amount of light at 405 nm was 3000 (mJ/cm ² ) using a high-pressure mercury lamp, and then the haze value was measured.

The haze value was measured according to JIS K7136 using a haze meter (Nippon Denshoku Kogyo Co., Ltd., NDH5000).

The haze value determined what was less than 0.5 as "(circle) (good)", what was 0.5 or more and less than 1.0 as "Δ (satisfactory)", and what was 1.0 or more as "x (poor)".

(9) Tg after photocuring

For each of the 150 μm photocurable adhesive sheets Y1 to Y14 (without release film) obtained in Examples and Comparative Examples, light was irradiated in advance so that the integrated light amount at 405 nm was 3000 (mJ/cm ² ), and then , Eight photocurable adhesive sheets Y1 to Y14 were stacked to a thickness of 1200 μm, using a dynamic viscoelasticity measuring device rheometer (“MARS” manufactured by Eco Seiki Co., Ltd.), adhesive jig: φ25 mm parallel plate, deformation: 0.5% , frequency of 1 Hz, temperature increase rate: 3 ° C./min, the temperature at which the obtained Tan δ value peaked was measured as Tg.

(10) Viscosity

For each of the 150 μm photocurable pressure-sensitive adhesive sheets Y1 to Y14 (without release film) obtained in Examples and Comparative Examples, 8 sheets were stacked to 1200 μm, and a dynamic viscoelasticity measuring device rheometer (“MARS, manufactured by Eco Seiki Co., Ltd.) "), under the conditions of adhesive jig: Φ25 mm parallel plate, deformation: 0.5%, frequency 1 Hz, temperature increase rate: 3 ° C./min, the adhesive sheet before photocuring at 70 ° C. and 100 ° C. Complex viscosity was measured.

(11) Storability

Photocurable pressure-sensitive adhesive sheets Y1 to Y14 cut into 50 mm x 50 mm squares were sandwiched between two sheets of 100 mm x 100 mm thick PET films, and a laminate was prepared at 23 ° C. Visual observation was performed to see if the adhesive was extruded from the layered product after leaving it for 300 hours in the environment.

The produced laminate was visually observed, and "x (poor)" indicates that the adhesive protruded as a whole, "Δ (satisfactory)" when the adhesive protruded only at the corners, and "○ (good)" when the adhesive did not protrude. judged

<Consideration>

The photocurable PSA sheet laminate (X/Y1 to Y10 laminate) of the resin member (X)/photocurable PSA sheet (Y1 to Y10) of Examples 1 to 10 has a wavelength of 405 nm from the resin member (X) side. When irradiated with light so that the cumulative light amount in 3000 (mJ/cm ² ), the photocurable adhesive sheets Y1 to Y10 can be sufficiently cured so that the difference in gel fraction is greater than 10%, and the dynamic storage modulus (G' ) maintained a high-temperature cohesive force of 0.7×10 ⁴ Pa or more at 120° C. and 1 Hz, and therefore, good anti-foaming reliability was obtained. In particular, good anti-foaming reliability was obtained in a test assuming a case where the touch sensor was a glass sensor.

Among them, in Examples 3, 7, 9, and 10, the dynamic storage modulus (G') at 120°C and 1 Hz maintained a high-temperature cohesive force of 2.0 × 10 ⁴ Pa or more, so when the touch sensor is a film sensor Also in the test assuming, good anti-foaming reliability was obtained.

Further, in Example 8, good anti-foaming reliability was obtained in the test assuming the case where the touch sensor was a film sensor, but peeling of the glass occurred in the test assuming the case where the touch sensor was a glass sensor. This is considered to be because the dynamic storage modulus (G') was excessively high at 120°C and 1 Hz, and the tack and adhesive performance deteriorated.

In Example 2, since the content of the hydrophilic monomer constituting the (meth)acrylic acid ester (co)polymer (a) was 10 parts by mass or less, phase separation proceeded during long-term storage, so the haze after long-term storage was "Δ (satisfactory)”.

In any of Examples 1 to 10, the step absorbency is good, and it is considered that the cover member having the step difference in printing can withstand practical use depending on the type of touch sensor.

Further, in Examples 4, 9, and 10, the viscosity (70°C) was as high as 1.5 kPa·s or more, and therefore, even after long-term storage, protrusion of glue was not found, and storage properties were excellent.

In Comparative Examples 1 and 2, the light transmittance (%) at a wavelength of 390 nm of the photocurable adhesive sheets Y11 and Y12 was as high as 90% or more, and the integrated light amount at a wavelength of 405 nm from the resin member (X) side was 3000 ( mJ/cm ² ), since the progress of the excitation and curing (crosslinking) reaction due to the light absorption of the photoinitiator when irradiated with light is not sufficient, the adhesive layer (Y) cannot be sufficiently cured, and the foam resistance reliability Air bubbles were generated during the test.

In Comparative Example 3, photocurable PSA sheet Y13 had a high gel fraction of 88% and a high dynamic storage modulus (G') (25°C) of 1.1×10 ⁵ Pa, resulting in poor step water absorption and air bubbles.

In Comparative Example 4, since the resin member (X) did not contain an ultraviolet absorber and the light transmittance at a wavelength of 365 nm was as high as 45%, yellowing in the UV reliability test progressed.

Claims (16)

A photocurable adhesive sheet used for bonding a front panel used in an image display device,
An adhesive layer (Y) having all the characteristics of (1) to (3) below,
The photocurable adhesive sheet according to claim 1 , wherein the front panel has a light transmittance of 10% or less at a wavelength of 365 nm and a light transmittance of 60% or more at a wavelength of 405 nm.
(1) The gel fraction (referred to as "gel fraction before light irradiation X1") is within 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) When irradiated with light having a cumulative amount of light 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 ("gel after light irradiation") It is photocurable so that the difference (gel fraction X2 after light irradiation minus gel fraction X1 before light irradiation) is 30% or more. According to claim 1,
The photocurable adhesive sheet characterized in that the adhesive layer (Y) contains a (meth)acrylic acid ester (co)polymer and a visible light initiator. According to claim 1,
The photocurable adhesive sheet in which the adhesive layer (Y) contains a silane coupling agent. According to claim 2,
The (meth)acrylic acid ester (co)polymer is chemically derived from a combination 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 any functional group selected from a carboxyl group and an isocyanate group. A photocurable adhesive sheet in which phosphorus bonds are formed. According to claim 2,
A photocurable adhesive sheet wherein the (meth)acrylic acid ester (co)polymer is a graft copolymer having a macromonomer as a branch component. According to claim 2,
The photocurable adhesive sheet in which the visible light initiator is a hydrogen abstraction type visible light initiator. According to claim 6,
The hydrogen drawing visible light initiator is phenylglyoxylic acid methyl ester, oxy-phenyl-acetic acid 2-[2-oxo-2-phenyl-acetoxy-ethoxy] ethyl ester and oxy-phenyl-acetic acid 2-[2- A photocurable pressure-sensitive adhesive sheet comprising any one or two selected from the group consisting of mixtures of hydroxy-ethoxy] ethyl esters. According to claim 2,
The photocurable adhesive wherein the (meth)acrylic acid ester (co)polymer is a copolymer comprising a straight-chain or branched alkyl (meth)acrylate having 4 to 18 carbon atoms in the side chain and a hydrophilic (meth)acrylate as a copolymerization component. Sheet. According to claim 1,
The photocurable adhesive sheet in which the adhesive layer (Y) contains a crosslinking agent or is formed using a crosslinking agent. According to claim 9,
The photocurable pressure-sensitive adhesive sheet wherein the crosslinking agent is an alkylene oxide unmodified tri- or higher-functional (meth)acrylate. According to claim 2,
The photocurable adhesive sheet wherein the (meth)acrylic acid ester (co)polymer has an active energy ray crosslinkable structural site. According to claim 1,
A photocurable adhesive sheet having a storage modulus (G') of 0.9×10 ⁵ Pa or less at a temperature of 25°C and a frequency of 1 Hz. According to claim 1,
The storage modulus (G') of the adhesive layer (Y) after irradiation with light having a cumulative amount of light of 3000 (mJ/cm ² ) at a wavelength of 405 nm is 0.7×10 ⁴ Pa or more at a temperature of 120°C and a frequency of 1 Hz. A photocurable adhesive sheet characterized in that it becomes. According to claim 1,
The storage modulus (G') of the adhesive layer (Y) after irradiation with light having a cumulative amount of light of 3000 (mJ/cm ² ) at a wavelength of 405 nm is 2.0×10 ⁴ Pa or more at a temperature of 120°C and a frequency of 1 Hz. A photocurable adhesive sheet characterized in that According to claim 1,
The photocurable adhesive sheet characterized in that the adhesive layer (Y) has a hot melt property that is softened or fluidized by heating. According to claim 1,
A photocurable adhesive sheet wherein the front panel is used for a vehicle-mounted image display device.