CN110997845A

CN110997845A - Photocurable adhesive sheet, photocurable adhesive sheet laminate, method for producing photocurable adhesive sheet laminate, and method for producing image display panel laminate

Info

Publication number: CN110997845A
Application number: CN201880051211.4A
Authority: CN
Inventors: 野泽大希; 福田晋也; 石井嘉穗儿; 稻永诚
Original assignee: Mitsubishi Chemical Corp
Current assignee: Mitsubishi Chemical Corp
Priority date: 2017-08-08
Filing date: 2018-08-06
Publication date: 2020-04-10
Anticipated expiration: 2038-08-06
Also published as: KR20200036015A; KR20220132017A; KR20230030047A; CN110997845B; TW202307167A; TW201920565A; KR102566971B1; KR102573795B1; WO2019031426A1; CN111909622A; KR102566966B1; CN111876091B; KR102566973B1; TWI785086B; CN111876091A; TWI822414B; CN111909622B; KR20220129682A; TW202309226A

Abstract

Disclosed is a photocurable adhesive sheet for bonding a resin member (X) having a light transmittance of 10% or less at a wavelength of 365nm and a light transmittance of 60% or more at a wavelength of 405nm, wherein the adhesive sheet is used for bonding a resin member (X) and has an adhesive layer (Y) having all the following characteristics (1) to (3). (1) The gel fraction is in the range of 0-60%. (2) The light transmittance at a wavelength of 390nm is 89% or less, and the light transmittance at a wavelength of 410nm is 80% or more. (3) Has photocurability which is cured by irradiation with light having a wavelength of 405 nm.

Description

Photocurable adhesive sheet, photocurable adhesive sheet laminate, method for producing photocurable adhesive sheet laminate, and method for producing image display panel laminate

Technical Field

The present invention relates to: a photocurable adhesive sheet having a property of being cured by irradiation with light (referred to as "photocuring") as an adhesive sheet for bonding a resin member having ultraviolet-ray-cutting properties that does not transmit ultraviolet rays.

Background

In recent years, in order to improve the visibility of an image display apparatus, the following operations are performed: by filling the gap between an image display panel such as a Liquid Crystal Display (LCD), a Plasma Display Panel (PDP), or an electroluminescence display (ELD) and a protective panel or a touch panel member disposed on the front surface side (visible side) thereof with an adhesive, reflection at the air layer interface of incident light or light emitted from a display image is suppressed.

As a method for filling the gap between the constituent members for an image display device with such an adhesive, the following methods are known: after filling the gap with a liquid adhesive resin composition containing an ultraviolet curable resin, the adhesive resin composition is cured by irradiation with ultraviolet light (patent document 1).

Further, a method of filling a gap between constituent members for an image display device with an adhesive sheet is also known. For example, patent document 2 discloses the following method: after the adhesive sheet crosslinked 1 time by ultraviolet rays was attached to an image display device constituting member, the adhesive sheet was irradiated with ultraviolet rays through the image display device constituting member and cured 2 times.

Patent document 3 proposes a novel transparent double-sided adhesive sheet which can fill up the height difference portion and can alleviate strain generated in the adhesive sheet and can maintain the foaming resistance in a high-temperature and high-humidity environment without deteriorating the recycling property when an image display device constituent member having the height difference portion on the adhering surface is adhered via the transparent double-sided adhesive sheet, the transparent double-sided adhesive sheet including: 1 or more (meth) acrylate (co) polymers; an ultraviolet polymerization initiator (A) having a molar absorption coefficient at a wavelength of 365nm of 10 or more and a molar absorption coefficient at a wavelength of 405nm of 0.1 or less; and a visible light polymerization initiator (B) having a molar absorption coefficient of 10 or more at a wavelength of 405nm, wherein a value (E '/G') obtained by dividing a dynamic storage modulus (E ') at 60 ℃ obtained by a stretching method by a dynamic storage modulus (G') at 60 ℃ obtained by a shearing method is 10 or more.

Documents of the prior art

Patent document

Patent document 1: international publication No. 2010/027041

Patent document 2: japanese patent No. 4971529

Patent document 3: japanese patent laid-open publication No. 2014-152295

Disclosure of Invention

Problems to be solved by the invention

As described above, when 2 image display device constituting members are bonded with a photocurable adhesive sheet, after 2 image display device constituting members are bonded once with the adhesive sheet, ultraviolet rays are irradiated from the outside of one image display device constituting member, and the adhesive sheet is cured by the ultraviolet rays through the image display device constituting member to perform secondary bonding.

According to such a method, since the adhesion reliability can be further improved by performing the primary adhesion while filling the unevenness of the adherend surface and finally performing the ultraviolet curing, the "level difference absorbing property" when the unevenness exists on the adherend surface of the member to be adhered (also referred to as "adhering member") and the "foaming resistance reliability after the adhesion can be both satisfied.

For example, in an image display device for vehicle mounting, a resin front panel is used in some cases, and a resin member such as a conductive member or a polarizing plate is disposed inside the front panel in order to prevent scattering of glass. In the above case, the front panel, the conductive member disposed inside the front panel, and the resin member such as the polarizing plate need to be prevented from deterioration such as yellowing due to exposure to ultraviolet rays, and therefore, the following operations are performed: the resin member exposed to ultraviolet rays is blended with an ultraviolet absorber to have ultraviolet absorbing properties.

However, in the above case, it is not possible to irradiate the ultraviolet ray from the outside of the image display device constituting member and to cure the adhesive sheet with the ultraviolet ray through the image display device constituting member as described above.

Therefore, when a resin front panel is bonded, a non-photocurable adhesive sheet which is not photocurable and is sufficiently cured to have a sufficient degree of reliability against foaming has to be used.

However, the above non-photocurable pressure-sensitive adhesive sheet is not necessarily satisfactory in terms of level difference absorption.

The present invention provides: a novel adhesive sheet which can be bonded to a resin member having ultraviolet ray cutting properties that do not transmit ultraviolet rays, and which can achieve both level difference absorption properties when irregularities are present on the surface to be bonded of the bonded member and foam resistance reliability after bonding.

Means for solving the problems

The invention provides a photocurable adhesive sheet for bonding a resin member (X) having ultraviolet ray cutting property which does not transmit ultraviolet rays, that is, a resin member (X) having a light transmittance of 10% or less at a wavelength of 365nm and a light transmittance of 60% or more at a wavelength of 405nm,

the photocurable adhesive sheet has an adhesive layer (Y) having all of the following characteristics (1) to (3).

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

(3) Has photocurability which is cured by irradiation with light having a wavelength of 405 nm.

The present invention also provides a photocurable adhesive sheet laminate comprising: the photocurable adhesive sheet has a structure in which a resin member (X) having a light transmittance of 10% or less at a wavelength of 365nm and a light transmittance of 60% or more at a wavelength of 405nm is laminated.

ADVANTAGEOUS EFFECTS OF INVENTION

The photocurable adhesive sheet proposed by the present invention has a gel fraction before photocuring of 0 to 60%, and therefore can obtain a level difference absorption property for filling level differences such as irregularities on a surface to be bonded, while having a light transmittance at a wavelength of 390nm of 89% or less and a photocurability for curing by irradiation with light having a wavelength of 405nm, and therefore, even if the resin member (X) to be bonded has a light transmittance at a wavelength of 365nm of 10% or less and a light transmittance at a wavelength of 405nm of 60% or more, it can be cured by irradiation with light having a wavelength of 405nm, and can improve cohesive force, and can obtain reliability against foaming after bonding.

In addition, the light transmittance at a wavelength of 410nm of the photocurable adhesive sheet proposed by the present invention is 80% or more, and therefore, the following effects can be obtained: the degree of Yellowness (YI) required for the adhesion of an optical member requiring transparency can be sufficiently low.

The photocurable adhesive sheet laminate according to the present invention can obtain the level difference absorption as described above, and the adhesive layer (Y) of the photocurable adhesive sheet has the following photocurability: when light having a wavelength of 405nm is irradiated from the outside of the resin member (X) through the resin member (X), the difference in gel fraction is increased by 10% or more, and therefore, by irradiating light having a wavelength of 405nm through the resin member (X) from the outside of the resin member (X), the adhesive layer (Y) can be cured, the cohesive force can be increased, and the reliability of the foam resistance after the adhesion can be obtained.

Detailed Description

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

The adhesive sheet

The pressure-sensitive adhesive sheet according to an embodiment of the present invention (referred to as "the present pressure-sensitive adhesive sheet") is a photocurable pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer (Y) having predetermined characteristics.

The adhesive sheet is a photocurable adhesive sheet which is cured by irradiation with light. In this case, the adhesive sheet may be cured with a room for photocuring (also referred to as "temporary curing") or uncured with photocurability (also referred to as "uncured").

If the pressure-sensitive adhesive sheet is temporarily cured or uncured, after the pressure-sensitive adhesive sheet is adhered to an adherend, the pressure-sensitive adhesive sheet can be photo-cured (also referred to as "main curing"), and as a result, the cohesive strength can be improved and the adhesiveness can be improved.

As a preferred embodiment of the above-mentioned photocurable pressure-sensitive adhesive sheet which is temporarily cured or uncured and has a property of being fully cured, that is, which is cured by irradiation with light having a wavelength of 405nm, there is a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer (Y) as shown in the following (1) to (3).

(1) The adhesive layer (Y) is as follows: the temporary curing is performed so that the gel fraction becomes 60% or less, and the main curing using the visible light initiator (c) can be performed by including the visible light initiator (c) described below.

(2) The adhesive layer (Y) is as follows: the visible light initiator (c-2) of the hydrogen abstraction type among the visible light initiators (c) described below is temporarily cured so that the gel fraction becomes 60% or less, whereby main curing by the visible light initiator (c-2) can be performed.

(3) The adhesive layer (Y) is as follows: the sheet shape is maintained without being cured, and main curing by the visible light initiator (c) can be performed by including the visible light initiator (c) described below.

Examples of the method for forming the adhesive layer (Y) in the above (1) include the following methods: the adhesive layer (Y) is formed by heating or curing a composition (an example of the present resin composition described later) comprising: a visible light initiator (c); a (meth) acrylate (co) polymer (a) having a functional group (i); a compound having a functional group (ii) reactive with the functional group (i); a crosslinking agent (b) such as a photopolymerizable compound having a carbon-carbon double bond (particularly a polyfunctional monomer) if necessary; and, further, if necessary, a silane coupling agent (d)).

According to this method, the functional group (i) in the (meth) acrylate (co) polymer reacts with the functional group (ii) in the compound to form a chemical bond, thereby curing (crosslinking) to form the adhesive layer (Y). By forming the adhesive layer (Y) in this manner, the visible light initiator (c) can be present in the adhesive layer (Y) in a state of remaining active.

Examples of the combination of the functional group (i) and the functional group (ii) include a carboxyl group and an epoxy group, a carboxyl group and an Aziridinyl group (Aziridinyl 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 preferable. More specifically, the (meth) acrylate copolymer (a) is particularly suitable when it has a hydroxyl group (the hydroxyl group-containing monomer described below is used) and the compound has an isocyanate group.

The compound having the functional group (ii) may further have a radical polymerizable functional group such as a (meth) acryloyl group. Thus, the adhesive layer (Y) can be formed while maintaining the photocurability (crosslinking) of the (meth) acrylate (co) polymer having a radical polymerizable functional group, specifically, the (meth) acrylate copolymer having an active energy ray-crosslinkable structural site described below. More specifically, the (meth) acrylate (co) polymer (a) having a hydroxyl group (the hydroxyl group-containing monomer described below is used), and the compound having a (meth) acryloyl group (e.g., 2-acryloyloxyethyl isocyanate, 2-methacryloyloxyethyl isocyanate, and 1,1- (bisacryloxymethyl) ethyl isocyanate) are particularly suitable examples.

In this way, the crosslinking reaction between the (meth) acrylate (co) polymers based on the radical polymerizable functional group is utilized, whereby there are advantages such as easy and efficient increase in the cohesive force after photocuring (crosslinking) without using the crosslinking agent (b), excellent reliability, and the like, and thus more preferable.

Preferred embodiments of the acrylate (co) polymer (a), the crosslinking agent (b), the visible light initiator (c), and the silane coupling agent (d) other than those described above are as follows.

Examples of the method for forming the adhesive layer (Y) in the above (2) include the following methods: as the visible light initiator (c), the following hydrogen abstraction type visible light initiator (c-2) was used. Even when the hydrogen abstraction initiator is excited once, the initiator returns to the ground state without any reaction, and thus can be reused as a visible light initiator. In this manner, by using the hydrogen abstraction-type visible light photoinitiator, the visible light curability (crosslinking) by the visible light photoinitiator can be maintained even after the temporary curing by the irradiation of the visible light.

The preferable modes of the visible light initiator (c-2) and the other aspects than the above are as follows.

Examples of the method for forming the adhesive layer (Y) in the above (3) include the following methods: the following macromonomers are used as the monomer components constituting the (meth) acrylic ester copolymer (a). More specifically, there is a method of using a graft copolymer having a macromonomer as a branch component. By using such a macromonomer, the branch components are attracted to each other at room temperature, and the composition (an example of the present resin composition described later) can be maintained in a physically crosslinked state.

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.

The preferable embodiments of the graft copolymer having the macromonomer as a branch component are as follows.

The present adhesive sheet is preferably used for adhering a resin member (X) described later.

The adhesive sheet may have a single-layer structure of the adhesive layer (Y), or may have a multilayer structure of 2 or more layers having the adhesive layer (Y). In the case of a multilayer, at least the outermost layer may be the adhesive layer (Y), and all the adhesive layers may be the adhesive layers (Y).

< adhesion layer (Y) >)

The adhesive layer (Y) preferably has all of the following characteristics (1) to (3).

(1) The gel fraction in a normal state, i.e., a state before light irradiation (referred to as "gel fraction before light irradiation X1") is in the range of 0 to 60%.

If the adhesive layer (Y) has a hot-melt property that softens or flows by heating, it is preferable because, when there is a level difference such as unevenness in the surface to be bonded of the adhesive member, the adhesive can be filled more easily in each part of the level difference, and the level difference absorption property can be further improved.

From the above viewpoint, the adhesive layer (Y) is preferably formed as the adhesive layer (Y) of the above (3).

(gel fraction)

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

If the gel fraction of the adhesive layer (Y) is 60% or less, there are sufficiently many uncrosslinked components (in a temporarily cured state or an uncured state) which are left to be cured by light irradiation, and it is preferable from the viewpoint that "the gel fraction X2 after light irradiation — the gel fraction X1 before light irradiation" can be 10% or more in the main curing.

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

In order to adjust the gel fraction (gel fraction X1 before light irradiation) of the adhesive layer (Y) to the above range, the residual catalyst may be sufficiently removed, or a polymerization inhibitor, an antioxidant, or the like may be used during polymerization of the present resin composition and processing of the adhesive sheet, which will be described later, so that an undesired curing (crosslinking) reaction by heat, light, or the like does not proceed before main curing, and in the case of performing temporary curing by light irradiation, the cumulative amount of light irradiated for temporary curing may be sufficiently reduced so that the amount of uncrosslinked components may be sufficiently increased. But is not limited to the above method.

Further, the adhesive layer (Y) preferably has photocurability to be cured by irradiation with light having a wavelength of 405nm, and the degree of photocurability is preferably, for example, as follows: when light having a wavelength of 405nm is irradiated from the outside of the resin member (X) through the resin member (X), the gel fraction is increased by 10% or more, particularly by 15% or more, particularly by 20% or more, particularly by 30% or more, particularly by 50% or more, in terms of the difference in gel fraction.

The term "light having an irradiation wavelength of 405 nm" means light having a sensitivity measured by an ultraviolet photometer, having a sensitivity with a wavelength of 405nm as a peak value and a gradual slope extending to a wavelength range of 320 to 470 nm.

Among them, the adhesive layer (Y) preferably has the following photocurability: the resin member (X) is irradiated from the outside thereof with a cumulative light quantity of 3000 (mJ/cm) at a wavelength of 405nm, for example, through the resin member (X)²) In the case of (1), the difference between the gel fraction after light irradiation (referred to as "gel fraction after light irradiation X2") and the gel fraction before light irradiation (gel fraction before light irradiation X1) (gel fraction after light irradiation X2-gel fraction before light irradiation X1) is 10% or more.

Therefore, it is preferable to have the following photocurability: for example, when the gel fraction X1 before light irradiation is 40%, the cumulative light quantity at an irradiation wavelength of 405nm is 3000 (mJ/cm)²) The gel fraction of the pressure-sensitive adhesive layer (Y) after light irradiation (referred to as "gel fraction X2 after light irradiation") is 50% or more.

When the gel fraction of the adhesive layer (Y) before and after photocuring is 10% or more, the adhesive layer (Y) has high cohesive strength even in a severe high-temperature and high-humidity environment, and the reliability of foaming resistance can be improved, which is preferable.

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

When the gel fraction difference of the adhesive layer (Y) before and after the light irradiation is adjusted to fall within the above range, the absorption by the photoinitiator may be present at a wavelength of 405 nm. But is not limited to the above method.

The "cumulative light amount at a wavelength of 405 nm" is the total amount of irradiation energy received per unit area, and is the total amount of irradiation energy measured by an ultraviolet cumulative light amount meter "UIT-250" (manufactured by USHIO INC.) and a light receiver "UVD-C405" (manufactured by USHIO INC.) in light irradiated by a high-pressure mercury lamp or the like, and is the cumulative light amount in a wavelength region corresponding to the light receiving characteristics of the light receiver (having sensitivity in a wavelength range where 405nm is a light receiving peak and the gentle slope extends to 320 to 470 nm). More specifically, the cumulative light amount is obtained by the method described in the examples.

(light transmittance)

The adhesive layer (Y) preferably has a light transmittance at a wavelength of 390nm of 89% or less and a light transmittance at a wavelength of 410nm of 80% or more.

In the adhesive compound containing a photoinitiator that absorbs in the ultraviolet to visible light region around 400nm, the photoinitiator has a large light absorption, and the lower the light transmittance at 390nm derived from the light absorption, the better the photosensitivity, and the easier the curing.

On the other hand, if the light transmittance at a wavelength of 410nm is not so high as to be constant or more, the adhesive layer (Y) is colored yellow, and it is difficult to use it for an optical member.

As the above object, it is preferable that the light transmittance at a wavelength of 390nm is 89% or less because the adhesive layer (Y) can secure sufficient visible light curability, and it is preferable that the light transmittance at a wavelength of 410nm is 80% or more because a sufficiently low Yellowness (YI) required for attaching an optical member requiring transparency can be achieved.

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

The light transmittance at a wavelength of 410nm is preferably 80% or more, more preferably 85% or more, particularly 90% or more.

In order to make the light transmittance of the adhesive layer (Y) as described above, it is possible to use a material having an absorption peak characteristic that the gradual slope of the absorption peak of an initiator absorbing visible light is sufficiently 390nm and the absorption peak becomes small at 410 nm. But is not limited to the above method.

(storage modulus)

The storage modulus (G') of the adhesive layer (Y) is preferably 0.9X 10 at a temperature of 25 ℃ and a frequency of 1Hz⁵Pa or less.

By having such viscoelastic properties, the adhesive sheet can obtain particularly excellent level difference absorbability against level differences such as irregularities of the surface to be bonded to be buried.

From the above viewpoint, the storage modulus (G') of the adhesive layer (Y) is preferably 0.9X 10 at a temperature of 25 ℃ and a frequency of 1Hz⁵Pa or less, more preferably 0.8X 10⁵Pa or less.

In the adhesive layer (Y), the cumulative quantity of light at an irradiation wavelength of 405nm was3000(mJ/cm²) The storage modulus (G') after light of (A) is preferably 0.7X 10 at a temperature of 120 ℃ and a frequency of 1Hz⁴Pa or above.

When the storage modulus (G') of the pressure-sensitive adhesive layer (Y) after photocuring is in the above range, the pressure-sensitive adhesive layer (Y) can be preferably prevented from foaming due to an exhaust component from the resin member (X) when a laminate with the resin member (X) is subjected to a high temperature test, a high temperature and high humidity test, or the like.

From the above-mentioned viewpoints, the storage modulus (G') of the pressure-sensitive adhesive layer (Y) after photocuring is preferably 0.7X 10 at a temperature of 120 ℃ and a frequency of 1Hz⁴Pa or more, more preferably 1.0X 10⁴Pa or more, more preferably 2.0X 10⁴Pa or above.

However, in an image display device having a touch panel function, a glass sensor, a film sensor, a polarizing plate glass (an external-fit type or an internal-fit type in which a sensor is incorporated inside), and the like are used separately according to a module design as a touch sensor disposed on the back side of a front panel/an adhesive layer, and the ease of occurrence of a failure in an environmental test differs depending on the configuration of a sensor member.

The experimental research results in the invention of the application are as follows: when the adhesive layer (Y) is used by being stuck with the resin member (X)/adhesive layer (Y)/glass sensor configuration, the preferred range of the storage modulus (G ') of the adhesive layer (Y) is as described above, while when the adhesive layer (Y) is used by being stuck with the resin member (X)/adhesive layer (Y)/film sensor configuration, the film sensor is generally 100 μm or less thin and less rigid, and the reliability improvement effect by the silane coupling agent is lower than the reliability improvement effect by the glass material, and therefore, in the hot and humid environment test, foaming is likely to occur as compared with the case of the glass sensor, and a higher level of the storage modulus (G') is required.

Accordingly, in view of the above, namely, the storage modulus (G') of the adhesive layer (Y) after photocuring when the adhesive layer (Y) is used by being stuck with the resin member (X)/adhesive layer (Y)/film sensor, that is, the cumulative light amount at an irradiation wavelength of 405nm is 3000 (mJ/cm)²) Light-time adhesion ofThe storage modulus (G') of the layer (Y) is preferably in the range of 2.0X 10⁴Pa or more, more preferably 5.0X 10⁴Pa or more, more preferably 8.0X 10⁴Pa or above.

(composition of adhesive layer (Y))

The adhesive layer (Y) may be formed of an adhesive composition (referred to as "present resin composition") containing: a (meth) acrylate (co) polymer (a), a visible light initiator (c), if necessary, a further crosslinking agent (b), if necessary, a further silane coupling agent (d), and if necessary, a further other material.

[ (meth) acrylate (co) Polymer (a) ]

The (meth) acrylate (co) polymer (a) is preferably photocurable.

It is to be noted that, "(meth) acrylic acid" is a meaning including acrylic acid and methacrylic acid, "(meth) acryloyl group" is a meaning including acryloyl group and methacryloyl group, and "(meth) acrylate" is a meaning including acrylate and methacrylate, respectively. "(Co) polymers" is used in a sense to include polymers and copolymers. In addition, "tablet" conceptually includes tablet, film, tape.

Examples of the (meth) acrylate (co) polymer (a) include, in addition to a homopolymer of an alkyl (meth) acrylate: and a copolymer obtained by polymerizing the monomer component with a monomer component copolymerizable therewith. For example, in addition to a homopolymer of an alkyl (meth) acrylate, a copolymer obtained by polymerizing a monomer component copolymerizable with the homopolymer and a monomer component copolymerizable with the homopolymer may be used.

More specifically, examples of the (meth) acrylate (co) polymer (a) include: copolymers of alkyl (meth) acrylates with monomer components copolymerizable therewith, for example comprising: the monomer composition is characterized by comprising (a) a carboxyl group-containing monomer (hereinafter also referred to as a "copolymerizable monomer A"), (B) a hydroxyl group-containing monomer (hereinafter also referred to as a "copolymerizable monomer B"), (C) an amino group-containing monomer (hereinafter also referred to as a "copolymerizable monomer C"), (D) an epoxy group-containing monomer (hereinafter also referred to as a "copolymerizable monomer D"), (E) an amide group-containing monomer (hereinafter also referred to as a "copolymerizable monomer E"), (F) a vinyl monomer (hereinafter also referred to as a "copolymerizable monomer F"), (G) a (meth) acrylate monomer having 1 to 3 carbon atoms in the side chain (hereinafter also referred to as a "copolymerizable monomer G") and (H) a macromonomer (hereinafter also referred to as a "copolymerizable monomer H").

The alkyl (meth) acrylate is preferably a linear or branched alkyl (meth) acrylate having a side chain of 4 to 18 carbon atoms.

Examples of the linear or branched alkyl (meth) acrylate having a side chain of 4 to 18 carbon atoms include: n-butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, neopentyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, heptyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, tert-butylcyclohexyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, hexadecyl (meth) acrylate, dodecyl (meth) acrylate, hexyl, 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. These can be used in 1 or 2 or more in combination.

Among the above, the linear or branched alkyl (meth) acrylate having 4 to 18 carbon atoms particularly preferably contains at least 1 kind of any one of butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate and isobornyl (meth) acrylate.

Examples of the copolymerizable monomer a include: (meth) acrylic acid, 2- (meth) acryloyloxyethyl hexahydrophthalic acid, 2- (meth) acryloyloxypropylhexahydrophthalic acid, 2- (meth) acryloyloxyethyl phthalic acid, 2- (meth) acryloyloxypropylphthalic acid, 2- (meth) acryloyloxyethyl maleic acid, 2- (meth) acryloyloxypropyl maleic acid, 2- (meth) acryloyloxyethyl succinic acid, 2- (meth) acryloyloxypropyl succinic acid, crotonic acid, fumaric acid, maleic acid, itaconic acid. These may be 1 or 2 or more in combination.

Examples of the copolymerizable monomer B include: hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 2-hydroxybutyl (meth) acrylate. These may be 1 or 2 or more in combination.

Examples of the copolymerizable monomer C include: aminoalkyl (meth) acrylates such as aminomethyl (meth) acrylate, aminoethyl (meth) acrylate, aminopropyl (meth) acrylate, aminoisopropyl (meth) acrylate, and N, N-dialkylaminoalkyl (meth) acrylates such as N-alkylaminoalkyl (meth) acrylate, N-dimethylaminoethyl (meth) acrylate, and N, N-dimethylaminopropyl (meth) acrylate. These may be 1 or 2 or more in combination.

Examples of the copolymerizable monomer D include: glycidyl (meth) acrylate, methyl glycidyl (meth) acrylate, 3, 4-epoxycyclohexylmethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate glycidyl ether. These may be 1 or 2 or more in combination.

Examples of the copolymerizable monomer E include: (meth) acrylamide, N-dimethyl (meth) acrylamide, N-butyl (meth) acrylamide, N-methylol (meth) acrylamide, N-methylolpropane (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, diacetone (meth) acrylamide, maleimide, and the like. These may be 1 or 2 or more in combination.

Examples of such a compound include alkyl (meth) acrylates having an alkyl group of 1 to 12 carbon atoms, functional monomers having a functional group such as a hydroxyl group, an amide group, and an alkoxyalkyl group in the molecule, polyalkylene glycol di (meth) acrylates, vinyl ester monomers such as vinyl acetate, vinyl propionate, and vinyl laurate, and aromatic vinyl monomers such as styrene, chlorostyrene, chloromethylstyrene, α -methylstyrene, and other substituted styrenes, and 1 or 2 or more kinds in combination thereof.

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

Examples of the copolymerizable monomer G include: methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, and the like. These may be 1 or 2 or more in combination.

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

The macromonomer as the copolymerizable monomer H is a high molecular monomer having a functional group at the end and a high molecular weight skeleton component, and is preferably a monomer having 20 or more carbon atoms in the side chain when polymerized into a (meth) acrylate copolymer.

By using the copolymerizable monomer H, a macromonomer can be introduced as a branch component of the graft copolymer, and the (meth) acrylate copolymer can be formed into a graft copolymer. For example, a (meth) acrylate copolymer (a-1) formed from a graft copolymer having a macromonomer as a branch component can be formed.

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

The backbone component of the macromonomer is preferably composed of an acrylate polymer or a vinyl polymer. Examples thereof include the linear or branched alkyl (meth) acrylate having 4 to 18 carbon atoms in the side chain, the copolymerizable monomer A, the copolymerizable monomer B, and the copolymerizable monomer G, and they may be used alone or in combination of 2 or more.

Among them, the dry component of the (meth) acrylate copolymer (a-1) preferably contains a hydrophobic (meth) acrylate and a hydrophilic (meth) acrylate as the structural units.

The hydrophobic (meth) acrylate is preferably an alkyl ester having no polar group (excluding methyl acrylate), and examples thereof include: n-butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, neopentyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, heptyl (meth) acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, isooctyl acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, tert-butylcyclohexyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, lauryl (meth) acrylate, hexadecyl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, behenyl (meth) acrylate, and mixtures thereof, Isobornyl (meth) acrylate, cyclohexyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, methyl methacrylate.

Examples of the hydrophobic vinyl monomer include vinyl acetate, styrene, t-butyl styrene, α -methyl styrene, vinyl toluene, and alkyl vinyl monomers.

On the other hand, as the hydrophilic (meth) acrylate monomer, methyl acrylate and esters having a polar group are preferable, and examples thereof include (meth) acrylic acid esters containing a hydroxyl group such as methyl acrylate, (meth) acrylic acid, tetrahydrofurfuryl (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, and glyceryl (meth) acrylate, (meth) acrylic acid, 2- (meth) acryloyloxyethyl hexahydrophthalic acid, 2- (meth) acryloyloxypropylhexahydrophthalic acid, 2- (meth) acryloyloxyethyl phthalic acid, 2- (meth) acryloyloxypropylphthalic acid, 2- (meth) acryloyloxyethyl maleic acid, 2- (meth) acryloyloxypropylmaleic acid, fumaric acid, maleic acid, itaconic acid, monomethyl maleate, monomethyl itaconate and other carboxyl group-containing monomers, maleic anhydride, itaconic anhydride and other monomers containing an acid group, glycidyl (meth) acrylate, α -ethyl glycidyl acrylate, 3, 4-epoxybutyl acrylate, and other monomers containing a hydroxyl group such as N-methoxy acrylamide, N-acrylamide, and N-dimethyl acrylamide, and N-ethylene glycol.

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 mercapto group.

The macromonomer preferably has a radical polymerizable group copolymerizable with other monomers. The radical polymerizable group may contain one or two or more, and among them, one is particularly preferable.

When the macromonomer has a functional group, the functional group may contain one or more, and among them, one is particularly preferable.

The radical polymerizable group and the functional group may contain either one or both of them. When both a radically polymerizable group and a functional group are contained, the number of the functional group or the radically polymerizable group other than any of the functional group added to the polymer unit composed of another monomer and the radically polymerizable group copolymerized with another monomer may be two or more.

Examples of the terminal functional group of the macromonomer include, in addition to a radical polymerizable group such as a methacryloyl group, an acryloyl group, and a vinyl group, a functional group such as a hydroxyl group, an isocyanate group, an epoxy group, a carboxyl group, an amino group, an amide group, and a mercapto group.

Among them, a radical polymerizable group copolymerizable with other monomers is preferable. The radical polymerizable group may contain one or two or more, and among them, one is particularly preferable. When the macromonomer has a functional group, the functional group may contain one or more, and among them, one is particularly preferable.

The number average molecular weight of the macromonomer is preferably 500 to 2 ten thousand, and among them, 800 or more or 8000 or less, particularly 1000 or more or 7000 or less.

The glass transition temperature (Tg) of the macromonomer is preferably higher than the glass transition temperature of the copolymer component constituting the (meth) acrylate (co) polymer (a-1).

Specifically, the glass transition temperature (Tg) of the macromonomer has an influence on the heat melting temperature (hot melt temperature) of the present adhesive sheet, and therefore, it is preferably from 30 ℃ to 120 ℃, more preferably 40 ℃ or higher or 110 ℃ or lower, and further preferably 50 ℃ or higher or 100 ℃ or lower.

When the glass transition temperature (Tg) of the macromonomer is as described above, the molecular weight can be adjusted so that the macromonomer can be hot-melted at a temperature of about 50 ℃ to 80 ℃ while maintaining excellent processability and storage stability.

The glass transition temperature of the macromonomer is the glass transition temperature of the macromonomer itself, and can be measured by a Differential Scanning Calorimeter (DSC).

In addition, in the state of room temperature, the branch components attract each other to maintain the state of forming physical crosslinks as the binder composition, and the physical crosslinks are released by heating to an appropriate temperature to obtain fluidity, so that the molecular weight and content of the macromonomer are also preferably adjusted.

From the above-mentioned viewpoint, the macromonomer is contained in the (meth) acrylate copolymer (a) in a proportion of preferably 5 to 30% by mass, more preferably 6 to 25% by mass, and further preferably 8 to 20% by mass.

In addition, the number average molecular weight of the macromonomer is preferably 500 to 10 ten thousand, of which preferably less than 8000, further preferably 800 or more or less than 7500, particularly 1000 or more or less than 7000.

The (meth) acrylate (co) polymer (a) preferably has an active energy ray-crosslinkable moiety.

The active energy ray-crosslinkable structure is a structural site which can form a crosslinked structure by reacting with a part of the (meth) acrylate copolymer (a) or by reacting with a curing component other than the (meth) acrylate copolymer (a) in the presence of a visible light initiator (c) described later.

Examples of the active energy ray-crosslinkable structural moiety include the following structures: a radical polymerizable functional group having a carbon-carbon double bond such as a functional group having an unsaturated double bond such as a (meth) acryloyl group or a vinyl group.

Since the polymer chains of the (meth) acrylate (co) polymer (a) have unsaturated double bonds, the polymer chains can be directly polymerized with each other even when the (meth) acrylate (co) polymer (a) does not contain a crosslinking agent, and the storage modulus (G') can be increased to a high level.

In the case of irradiation with active energy rays, any light source including light having a wavelength of 405nm may be used, and a visible light LED light source, a high-pressure mercury lamp, or the like may be used in view of curing speed, ease of availability of an irradiation device, cost, and the like.

In order to introduce a structure having a radical polymerizable functional group having a carbon-carbon double bond such as a functional group having an unsaturated double bond, for example, the (meth) acrylate (co) polymer (a) may be copolymerized with a monomer having a functional group in advance, and then a compound having a carbon-carbon double bond such as a functional group reactive with the functional group (for example, 2-isocyanatoethyl (meth) acrylate) and a monomer having an unsaturated double bond may be reacted with the compound while maintaining the curability of the carbon-carbon double bond.

Among them, the (meth) acrylate copolymer (a) is preferably a (meth) acrylate (co) polymer (a-2) containing a monomer component of a (meth) acrylate monomer having an active energy ray-crosslinkable structural site and having a linear alkyl group having 10 to 24 carbon atoms.

Examples of such (meth) acrylate (co) polymer (a-2) include: decyl (meth) acrylate (having 10 carbon atoms in the alkyl group), lauryl (meth) acrylate (having 12 carbon atoms), tridecyl (meth) acrylate (having 13 carbon atoms), cetyl (meth) acrylate (having 16 carbon atoms), stearyl (meth) acrylate (having 18 carbon atoms), behenyl (meth) acrylate (having 22 carbon atoms), and the like. These may be used alone, or 2 or more kinds may be used in combination.

In addition, in the (meth) acrylic acid linear alkyl ester monomer (a) having an alkyl group having 10 to 24 carbon atoms, an alkyl methacrylate is preferably used from the viewpoint of reducing the dielectric constant and lowering the glass transition temperature of the acrylic resin, and particularly preferably an alkyl group having 12 to 20 carbon atoms, and most preferably stearyl methacrylate, lauryl methacrylate and tridecyl methacrylate.

The content of the alkyl (meth) acrylate monomer (a) having a linear alkyl group having 10 to 24 carbon atoms is 50 to 94% by weight, preferably 60 to 83% by weight, and particularly preferably 70 to 80% by weight based on the total (co) polymerization components. When the amount is within the above range, there is no fear that the dielectric constant becomes high or the thermal stability of the resin is lowered.

[ crosslinking agent (b) ]

The crosslinking agent (b) is preferably a crosslinking agent having at least double bonds for crosslinking. Examples thereof include: the crosslinking agent having at least 1 crosslinkable functional group 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 may be used in combination of 1 or 2 or more.

In particular, by using 2 or more kinds of crosslinking agents in combination, a higher storage modulus (G') can be achieved even when the total amount of the crosslinking agents is the same as compared with the case where the crosslinking agents are used individually.

Therefore, it is more preferable to use 2 or more crosslinking agents (b) in combination.

The present invention also includes a case where the crosslinking agent (b) is chemically bonded to the (meth) acrylate (co) polymer (a).

Among them, a photopolymerizable compound having a carbon-carbon double bond, particularly a polyfunctional (meth) acrylate, is preferably used. Here, polyfunctional means having 2 or more crosslinkable functional groups. If necessary, the crosslinkable functional group may have 3 or more and 4 or more.

The crosslinkable functional group may be protected by a protecting group capable of deprotection.

Examples of the polyfunctional (meth) acrylate include: 1, 4-butanediol di (meth) acrylate, glycerol di (meth) acrylate, neopentyl glycol di (meth) acrylate, glycerol glycidyl ether di (meth) acrylate, 1, 6-hexanediol di (meth) acrylate, 1, 9-nonanediol di (meth) acrylate, tricyclodecane dimethacrylate, tricyclodecane dimethanol di (meth) acrylate, bisphenol A polyethoxy di (meth) acrylate, bisphenol A polypropoxy di (meth) acrylate, bisphenol F polyethoxy di (meth) acrylate, ethylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane triethoxy ethyl (meth) acrylate, epsilon-caprolactone-modified tris (2-hydroxyethyl) isocyanurate tri (meth) acrylate, ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, ethylene, 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, tripentaerythritol penta (meth) acrylate, hydroxypivalic acid neopentyl glycol di (meth) acrylate, di (meth) acrylate of the epsilon-caprolactone adduct of hydroxypivalic acid neopentyl glycol, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, ethoxylated pentaerythritol tri (meth) acrylate, polyethylene glycol tetra (meth) acrylate, and mixtures thereof, Ultraviolet-curable polyfunctional (meth) acrylic monomers such as trimethylolpropane polyethoxy tri (meth) acrylate and ditrimethylolpropane tetra (meth) acrylate; and polyfunctional (meth) acrylic oligomers such as polyester (meth) acrylates, epoxy (meth) acrylates, urethane (meth) acrylates, and polyether (meth) acrylates. These can be used in 1 or 2 or more in combination.

Among the above polyfunctional (meth) acrylates, from the viewpoint of imparting high cohesive force, a structure in which the distance between crosslinking sites in the formed crosslinked structure is short and the crosslinking density is dense is preferable, for example, an alkylene oxide-unmodified polyfunctional (meth) acrylate having 3 or more functions is preferable, and the polyfunctional (meth) acrylate (b-1) selected from the group consisting of pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, tripentaerythritol hexa (meth) acrylate, tripentaerythritol penta (meth) acrylate, trimethylolpropane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate is preferable.

The polyfunctional (meth) acrylate (b-1) may be used in 1 kind or in combination of 2 or more kinds (in the form of a mixture).

In the case where the polyfunctional (meth) acrylate (b-1) is used as a crosslinking agent, the (meth) acrylate (a) is preferably a copolymer of monomer components containing a hydrophilic monomer as a polar component from the viewpoint of compatibility.

Since the (meth) acrylate (a) contains a polar component, the compatibility with the polyfunctional (meth) acrylate (b-1) is good, the mixture is easy to mix during mixing, phase separation during long-term storage in an uncrosslinked state is not likely to occur, and there is no fear of an increase in haze value.

Specifically, the (meth) acrylate (co) polymer (a) is preferably a copolymer of the alkyl (meth) acrylate and a monomer component containing, as a copolymerizable monomer, at least methyl (meth) acrylate suitably selected from the copolymerizable monomers a to G, particularly the hydrophilic (meth) acrylate, or a copolymerizable monomer selected from the copolymerizable monomers G.

Further, the (meth) acrylate (co) polymer (a) is particularly preferably a copolymer containing at least methyl (meth) acrylate and having a monomer component in which the total amount of hydrophilic monomers (selected from the copolymerizable monomers a to G) accounts for 10 parts by mass or more of the entire (meth) acrylate (co) polymer (a).

The (meth) acrylate (co) polymer (a-1) is preferably a copolymer containing the linear or branched alkyl (meth) acrylate having 4 to 18 carbon atoms in the side chain as a skeleton component (dry component) and the hydrophilic monomer as a monomer component copolymerizable therewith.

The content of the crosslinking agent (b) is preferably 0.5 to 50 parts by mass, particularly 1 part by mass or more or 40 parts by mass or less, particularly 5 parts by mass or more or 30 parts by mass or less, based on 100 parts by mass of the (meth) acrylate (co) polymer (a).

[ visible light initiator (c) ]

The visible light initiator (c) is preferably a visible light initiator which generates radicals by irradiation with visible light, light having a wavelength of at least 390nm, 405nm and 410nm, for example, light having a wavelength region of 380nm to 700nm, and becomes a reaction starting point of the (meth) acrylate (co) polymer (a).

However, the visible light initiator (c) may generate radicals only by irradiation with visible light, or may generate radicals by irradiation with light in a wavelength region other than the visible light region.

The visible light initiator (c) preferably has an absorption coefficient at a wavelength of 405nm of 10 mL/(g.cndot.cm) or more, more preferably 15 mL/(g.cndot.cm) or more, particularly 25 mL/(g.cndot.cm) or more. The absorption coefficient at a wavelength of 405nm is 10 mL/(g.cndot.) or more, so that curing (crosslinking) by irradiation with visible rays can be sufficiently performed.

On the other hand, the upper limit of the absorption coefficient at a wavelength of 405nm is preferably 1X 10⁴mL/(g./cm) or less, more preferably 1X 10³mL/(g. cndot./cm) or less. It is also possible to use a photoinitiator having an absorption coefficient at a wavelength of 405nm of less than 10 mL/(g./cm).

Photoinitiators are roughly classified into 2 groups according to the mechanism of radical generation, and can be classified into: a cleavage type photoinitiator which can generate free radicals by cleaving and decomposing a single bond of the photoinitiator itself; and a hydrogen abstraction photoinitiator, wherein the photoinitiator after photoexcitation forms an excited complex with a hydrogen donor in the system, and hydrogen of the hydrogen donor can be converted.

Among them, the cleavage type photoinitiator is decomposed into other compounds when radical generation is caused by light irradiation, and if it is excited once, it does not function as a reaction initiator. Therefore, it is preferable that the active material does not remain in the binder after the completion of the crosslinking reaction, and the binder unexpectedly causes the possibility of light deterioration or the like.

In addition, regarding the coloring peculiar to the photoinitiator, in the case where a cleavage type visible light photoinitiator (c-1) for curing the binder by irradiating visible light rays has been conventionally added, there is a fear of coloring. Therefore, it is preferable to select the visible light initiator (c) which is discolored by disappearance of absorption of the visible light region of the reaction decomposition product.

On the other hand, a hydrogen abstraction type photoinitiator can maintain its function as a reaction initiator even after a plurality of light irradiations, and since a decomposition product such as a cleavage type photoinitiator is not generated when a radical is reacted by irradiation with an active energy ray such as ultraviolet ray, it is not easily volatile after the reaction is completed, and damage to an adherend can be reduced, which is useful.

In this way, the hydrogen abstraction-type visible light polymerization initiator (c-2) which initiates polymerization by being excited by visible light is particularly preferable.

Examples of the cleavage type visible light initiator (c-1) include: 2, 2-dimethoxy-1, 2-diphenylethan-1-one, 1-hydroxycyclohexylphenyl ketone, 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); poly (1-hydroxy-2-methyl-1-one, poly (2-hydroxy, 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) 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 them, acylphosphine oxide-based photoinitiators such as bis (2,4, 6-trimethylbenzoyl) -phenylphosphine oxide, 2,4, 6-trimethylbenzoyl diphenylphosphine oxide, (2,4, 6-trimethylbenzoyl) ethoxyphenylphosphine oxide, and bis (2, 6-dimethoxybenzoyl) 2,4, 4-trimethylpentylphosphine oxide are preferable in that they are decomposed after the reaction and discolored.

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

Of these, preferred is any 1 or 2 selected from the group consisting of methyl phenylglyoxylate, 2- [ 2-oxo-2-phenyl-acetoxy-ethoxy ] ethyl oxy-phenyl-acetate and 2- [ 2-hydroxy-ethoxy ] ethyl oxy-phenyl-acetate.

The visible light initiator (c) is not limited to the above-listed substances. Any one or a derivative of the above-listed visible light initiator (c) may be used, or two or more thereof may be used in combination.

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

The content of the visible light initiator (c) is not particularly limited. The content is preferably 0.1 to 10 parts by mass, 0.5 part by mass or more or 5 parts by mass or less, or 1 part by mass or more or 3 parts by mass or less, based on 100 parts by mass of the (meth) acrylate (co) polymer (a) in the adhesive layer (Y).

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

[ silane coupling agent (d) ]

The silane coupling agent (d) can improve adhesion, and among them, can improve adhesion to a glass material.

Examples of the silane coupling agent include: and compounds having an unsaturated group such as a vinyl group, an acryloyloxy group or a methacryloyloxy group, a hydrolyzable functional group such as an amino group or an epoxy group, and an alkoxy group.

Specific examples of the silane coupling agent include N- (β -aminoethyl) - γ -aminopropyltrimethoxysilane, N- (β -aminoethyl) - γ -aminopropylmethyldimethoxysilane, γ -aminopropyltriethoxysilane, γ -glycidoxypropyltrimethoxysilane and γ -methacryloxypropyltrimethoxysilane.

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

The silane coupling agent may be used alone in 1 kind or in combination of 2 or more kinds.

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

As with the silane coupling agent, a coupling agent such as an organotitanate compound can also be effectively used.

[ other materials ]

Examples of the components other than those described above contained in the present resin composition for forming the adhesive layer (Y) include: various additives such as a light stabilizer, an ultraviolet absorber, a metal deactivator, a metal corrosion inhibitor, an anti-aging agent, an antistatic agent, a moisture absorbent, a foaming agent, an antifoaming agent, inorganic particles, a viscosity modifier, a tackifier resin, a photosensitizer, and a fluorescent agent, and a reaction catalyst (a tertiary amine compound, a quaternary ammonium compound, a tin laurate compound, and the like).

In addition, known components blended in a general adhesive composition may be appropriately contained.

In addition, 2 or more kinds of each component may be used in combination.

Among the above, the present resin composition for forming the adhesive layer (Y) particularly preferably contains an ultraviolet absorber. As described above, since the adhesive layer (Y) has photocurability to be cured by irradiation with light having a wavelength of 405nm, the incorporation of an ultraviolet absorber does not inhibit the photocuring. Therefore, by containing the ultraviolet absorber, it is also possible to combine excellent ultraviolet ray-cutting properties without impairing the properties of the adhesive sheet.

Examples of the ultraviolet absorber include: benzotriazole-based ultraviolet absorbers, benzophenone-based ultraviolet absorbers, triazine-based ultraviolet absorbers, and the like. The ultraviolet absorber may be used alone or in combination of 2 or more.

Among them, the triazine-based ultraviolet absorber is particularly preferable from the viewpoint of transparency, ultraviolet absorbability and compatibility.

[ preferred composition of the resin composition ]

Examples of the preferred present resin composition for forming the adhesive layer (Y) include the following: which comprises (meth) acrylate (co) polymer (a), the above-mentioned crosslinking agent (b), visible light initiator (c), and, if necessary, silane coupling agent.

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

Among them, the (meth) acrylate (co) polymer (a) preferably forms a chemical bond based on a combination of any functional group selected from a carboxyl group and an epoxy group, a carboxyl group and an aziridine group, a hydroxyl group and an isocyanate group, an amino group and an isocyanate group, and a carboxyl group and an isocyanate group.

The (meth) acrylate (co) polymer (a) is preferably a copolymer containing, as copolymerization components, the linear or branched alkyl (meth) acrylate having 4 to 18 carbon atoms in the side chain and the hydrophilic (meth) acrylate.

Further, the crosslinking agent (b) is preferably the above-mentioned polyfunctional (meth) acrylate (b-1).

Examples of the preferred present resin composition for forming the adhesive layer (Y) include the following: which comprises the above (meth) acrylic ester copolymer (a-1) of a graft copolymer comprising a macromonomer as a branching component, the above crosslinking agent (b), a visible light initiator (c), and, if necessary, a silane coupling agent.

Among them, the (meth) acrylate (co) polymer (a-1) is preferably a copolymer containing, as a skeleton component (dry component), a linear or branched alkyl (meth) acrylate having 4 to 18 carbon atoms in the side chain and the hydrophilic (meth) acrylate as copolymerization components.

The crosslinking agent (b) is preferably the above-mentioned polyfunctional (meth) acrylate (b-1).

As another example of the preferable present resin composition for forming the adhesive layer (Y), the following composition can be given: the composition contains the (meth) acrylate copolymer (a-1) comprising a graft copolymer having a macromonomer as a branched component and having an active energy ray-crosslinkable structural site, the crosslinking agent (b), the visible light initiator (c), and, if necessary, a silane coupling agent.

When the adhesive layer (Y) is formed from the present resin composition having the above-mentioned composition, the adhesive layer (Y) comprising the (meth) acrylate copolymer (a) or (a-1) as a base resin can exhibit self-adhesiveness while maintaining a sheet shape at room temperature, and the adhesive can be filled in various portions of the height difference of the surface to be adhered of the adhesive member. Further, the visible light initiator (c) can be photo-cured by irradiation with visible light, and the cohesive force can be increased by photo-curing, whereby the reliability of foaming resistance can be improved.

By further adding a silane coupling agent, the adhesion, particularly to a glass material, can be further improved.

In addition to the above, the adhesive layer (Y) comprising the (meth) acrylate copolymer (a-1) as a base resin has a hot-melt property that melts or flows when heated, and therefore can have a higher level difference absorbency.

As another example of the preferable present resin composition for forming the adhesive layer (Y), the following composition can be given: the composition contains a (meth) acrylate (co) polymer (a-2) containing a monomer component of a (meth) acrylate monomer having an active energy ray-crosslinkable structural site and a linear alkyl group having 10 to 24 carbon atoms, the crosslinking agent (b), the visible light initiator (c), and, if necessary, a silane coupling agent. Among them, it is preferable to use, as the visible light initiator (c), a visible light initiator (c) having an absorption coefficient at a wavelength of 405nm of 10 mL/(g.cndot.cm) or more, and it is particularly preferable to use, as the visible light initiator (c), the cleavage type visible light initiator (c-1) and/or the hydrogen abstraction type visible light initiator (c-2).

When the present resin composition having the above-mentioned composition is used, the adhesive layer (Y) can be formed to be temporarily cured or uncured in a state where a room for photocuring is left, and then photocuring can be performed by 1 or 2 or more times of irradiation with visible light. Thus, for example, after the adhesive sheet is adhered to an adherend, the adhesive sheet can be photo-cured ("main-cured") by irradiation with visible light, and the main-cured adhesive sheet can improve the cohesive strength and the reliability against foaming.

In particular, when a (meth) acrylate (co) polymer having high fluidity at room temperature and having difficulty in storage stability is subjected to a step of improving storage stability by temporary curing, it can be cured by a subsequent step of visible light curing after the application.

(laminated Structure)

As described above, when the adhesive layer (Y) is formed by lamination, the adhesive layer (Y) using the present resin composition is preferably a front layer or a back layer as an outermost layer from the viewpoint of foaming resistance.

In this case, the thickness of the adhesive layer (Y) as the front and back layers is preferably 15 μm or more, more preferably 20 μm or more. If the thickness of the pressure-sensitive adhesive layer (Y) is 15 μm or more, it is preferable in terms of less fear of generating a trouble such as foaming against the exhaust pressure generated from the adherend member in the reliability test.

In addition, from the viewpoint of having storage stability as well, it may be preferable to further include another layer having a higher viscosity than the adhesive layer (Y).

That is, the adhesive layer (Y) formed of a graft copolymer containing a macromonomer is in an uncrosslinked state before photocuring, and if a polyfunctional (meth) acrylate monomer is used, the adhesive layer (Y) before photocuring may be a layer having a low viscosity by the action of the polyfunctional (meth) acrylate monomer component.

Therefore, in such a case, it is preferable to laminate another layer (Z) having a higher viscosity than the adhesive layer (Y) on the adhesive layer (Y).

For example, if the adhesive layer (Y)/layer (Z)/adhesive layer (Y) is a multilayer structure including 3 layers, excellent storage stability can be achieved.

From the viewpoint of such storage stability, the viscosity of the other layer (Z) is in the range of 70 ℃ to 100 ℃, preferably 1 to 10kPa · s, more preferably 1.5 to 5kPa · s.

The viscosity is a value measured according to the method described in examples.

In the case where the pressure-sensitive adhesive sheet has a multilayer structure as described above, the glass transition temperature (Tg) of the pressure-sensitive adhesive sheet after irradiation with light of 405nm is preferably lower than 20 ℃, more preferably lower than 10 ℃ from the viewpoint of further achieving impact absorption resistance.

The present adhesive sheet has such a low Tg, and thus has improved low-temperature adhesive properties (low-temperature peel strength, etc.), and can have impact absorption resistance.

Therefore, from the viewpoint of impact absorption resistance, the Tg of the other layer laminated with the adhesive layer (Y) after irradiation with light of 405nm is particularly preferably lower than 15 ℃, particularly lower than 10 ℃, particularly lower than 5 ℃.

The Tg is a value measured at the peak temperature of Tan δ of dynamic viscoelasticity, and specifically a value measured by the method described in examples.

< adhesive sheet with Release film >

The adhesive sheet may also be a release film-equipped adhesive sheet.

For example, a release film-attached pressure-sensitive adhesive sheet may be formed by forming a single-layer or multi-layer sheet-like pressure-sensitive adhesive layer on a release film.

As a material of the release film, a known release film can be suitably used.

As the material of the release film, for example, the following can be appropriately selected and used: coating silicone resin on films such as polyester film, polyolefin film, polycarbonate film, polystyrene film, acrylic film, cellulose triacetate film, fluororesin film, etc., and subjecting to mold release treatment; release paper, and the like.

When release films are laminated on both sides of the present psa sheet, one release film may be of the same laminated structure or material as the other release film, or may be of a different laminated structure or material.

The thicknesses may be the same or different.

Further, release films having different peeling forces and release films having different thicknesses may be laminated on both sides of the present pressure-sensitive adhesive sheet.

The light transmittance of the release film for light having a wavelength of 410nm or less is preferably 40% or less.

By laminating a release film having a light transmittance of 40% or less at a wavelength of 410nm or less on at least one side of the adhesive sheet, photopolymerization by irradiation with visible light can be effectively prevented from progressing.

From the above-mentioned viewpoint, the light transmittance of the release film laminated on one or both surfaces of the present pressure-sensitive adhesive sheet at a wavelength of 410nm or less is preferably 40% or less, more preferably 30% or less, particularly 20% or less.

Here, examples of the release film having a light transmittance of light having a wavelength of 410nm or less of 40% or less, that is, a film having an effect of shielding transmission of part of visible light and ultraviolet light include: a laminated film having an ultraviolet absorbing layer, which is formed by coating a releasable micro-adhesive resin on one surface of a polyester, polypropylene or polyethylene cast film or a stretched film and coating a coating material containing an ultraviolet absorber on the other surface.

In addition, there may be mentioned: a removable micro-adhesive resin mixed with an ultraviolet absorber is coated on one surface of a polypropylene-based, polyethylene-based cast film or a stretched film.

In addition, there may be mentioned: and a method for producing the same, wherein a slightly adhesive resin having removability is applied to a casting film or a stretched film made of a polyester, polypropylene or polyethylene resin containing an ultraviolet absorber.

In addition, there may be mentioned: and a multilayer cast film and a multilayer stretched film each of which is formed by molding a layer made of a resin not containing an ultraviolet absorber on one or both surfaces of a layer made of a polyester, polypropylene or polyethylene resin containing an ultraviolet absorber, and coating a releasable micro adhesive resin on one surface of the multilayer cast film and the multilayer stretched film.

In addition, there may be mentioned: an ultraviolet absorbing layer is formed by coating one surface of a casting film or a stretched film made of polyester, polypropylene or polyethylene resins with a coating containing an ultraviolet absorber, and a micro-adhesive resin having removability is further coated on the ultraviolet absorbing layer.

In addition, there may be mentioned: the ultraviolet absorbing layer is formed by coating one surface of a casting film or a stretched film made of polyester, polypropylene or polyethylene resins with a coating containing an ultraviolet absorber, and the other surface is coated with a removable micro-adhesive resin.

Further, there may be mentioned: and a laminate obtained by laminating the other surface of a resin film made of a polyester, polypropylene or polyethylene resin having a releasable micro adhesive resin applied to one surface thereof with a separately prepared resin film via an adhesive layer or an adhesive layer containing an ultraviolet absorber.

The above-mentioned thin film may have an antistatic layer, a hard coat layer, an anchor layer, and other layers as needed.

The thickness of the release film is not particularly limited. Among them, for example, from the viewpoint of processability and workability, 25 to 500 μm is preferable, and of these, 38 to 250 μm is more preferable, and 50 to 200 μm is particularly preferable.

As described above, the present pressure-sensitive adhesive sheet may be prepared by the following method: a method of directly extruding the present resin composition without using an adherend or a release film; a method of molding by injecting into a mold.

Further, the present resin composition can be directly filled between members constituting an image display device to be an adherend to form a psa sheet.

< method for producing adhesive sheet >

An example of a method for producing the adhesive sheet will be described.

First, the present resin composition can be prepared by mixing a (meth) acrylate (co) polymer (a), a visible light initiator (c), if necessary, a crosslinking agent (b), if necessary, a silane coupling agent (d), and if necessary, other materials in predetermined amounts.

The method for mixing them is not particularly limited, and the order of mixing the components is not particularly limited. In addition, the composition may be produced by introducing a heat treatment step, and in the above case, it is desirable to mix the components of the present resin composition in advance and then perform heat treatment.

Further, those obtained by concentrating and masterbatch-forming various mixed components may be used.

The apparatus for mixing is not particularly limited, and examples thereof include a universal mixer, a planetary mixer, a Banbury mixer, a kneader, a gate mixer, a pressure kneader, a three-roll mixer, and a two-roll mill. If necessary, a solvent may be used for mixing.

The resin composition can be used as a solvent-free system containing no solvent. By using the resin as a solvent-free system, the resin has an advantage that heat resistance and light resistance can be improved without leaving a solvent.

From the above-mentioned viewpoint, the present resin composition is also preferably in a form containing the (meth) acrylate (co) polymer (a), the crosslinking agent (b), and the visible light initiator (c).

The adhesive sheet can be produced by applying (coating) the present resin composition prepared as described above on a substrate sheet or a release sheet.

For example, the present pressure-sensitive adhesive sheet having a laminated structure can be produced by the following method: a method of coating (coating) the present resin composition on a substrate sheet or a release sheet to form a 1 st layer, coating (coating) the present resin composition on the formed 1 st layer to form a 2 nd layer, and repeating the operation; a method in which the 1 st and 2 nd layers are formed in advance and then the respective coated (coated) surfaces are bonded to each other, as described above; the present resin composition is formed simultaneously into the 1 st and 2 nd layers by multilayer coating or coextrusion.

The coating (coating) method is not particularly limited as long as it is a general coating method. Examples of the method include roll coating, die coating, gravure coating, comma coating, and screen printing.

Then, if necessary, the adhesive layer formed of the present resin composition may be irradiated with light to temporarily cure the adhesive layer (Y), leaving a room for photocuring, so that the gel fraction of the adhesive layer (Y) is 0 to 60%. However, the adhesive layer (Y) may be temporarily cured without being irradiated with light, and may be temporarily cured by heat or curing, or may be left uncured as it is.

< use of the adhesive sheet >

The adhesive sheet can be suitably used for bonding a resin member (X) as described above. This makes it possible to provide a pressure-sensitive adhesive sheet laminate (referred to as "the present pressure-sensitive adhesive sheet laminate") having a structure in which a resin member (X) having predetermined properties is laminated with the present pressure-sensitive adhesive sheet.

The adhesive sheet laminate can be produced, for example, as follows: the adhesive sheet can be produced by preparing the adhesive sheet from a resin composition containing a (meth) acrylate (co) polymer and a visible light initiator, and laminating the adhesive sheet on the resin member (X). However, the method for producing the adhesive sheet laminate is not limited to the above method.

(resin Member (X))

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

If the light transmittance at 365nm of the resin member (X) is 10% or less and the light transmittance at 405nm of the resin member (X) is 60% or more, the transmission of ultraviolet rays can be sufficiently blocked (reduced), the light deterioration of the resin member (X) itself and an optical member (for example, an optical film such as a polarizing film or a retardation film) positioned on the back side thereof (the side opposite to the visible side surface) can be suppressed, and the Yellowness (YI) can be reduced to a level required for the optical member.

Examples of such a resin member (X) include: a resin material as a main component, and an ultraviolet absorber for adjusting the light transmittance.

Examples of the resin material include: a material containing a polycarbonate resin or an acrylic resin as a main component resin.

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

The present adhesive sheet can also be used to produce an image display panel laminate, for example, as follows: the resin member (X) and an image display panel (P) are bonded via the adhesive sheet to form a photocurable adhesive sheet laminate, and the adhesive sheet is irradiated from the resin member (X) side with the resin member (X) so that the cumulative light amount at 405nm becomes 3000 (mJ/cm)²) The adhesive layer (Y) is photocured to a gel fraction difference of 10% or more before and after photocuring, and the resultant is collected to produce an image display panel laminate.

The adhesive sheet laminate can be attached to, for example, an image display panel (P) to produce an image display panel laminate.

Specifically, an image display panel laminate having a configuration in which the adhesive sheet laminate of the present invention is bonded to an image display panel (P) can be produced, for example, as follows: after a resin member (X) and an image display panel (P) are laminated via the adhesive sheet, light with a wavelength of 405nm is irradiated from the outside of the resin member (X) through the resin member (X) to completely cure the adhesive layer (Y) of the adhesive sheet, and the resin member (X) and the image display panel (P) are bonded to each other, thereby manufacturing an image display panel laminate.

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

(image display Panel (P))

The image display panel (P) is composed of, for example, other optical films such as a polarizing film and a retardation film, a liquid crystal material, and a backlight system (generally, the surface of the present composition or adhesive article to be bonded to the image display panel is an optical film), and the control method of the liquid crystal material includes an STN method, a VA method, an IPS method, and the like, and any method can be used.

The image display panel may be an in-cell type in which a touch panel function is built in a TFT-LCD, or an out-cell type in which a touch panel function is built in between a polarizing plate and a glass substrate provided with a color filter.

In the present adhesive sheet, the adhesive layer (Y) in a state in which the target product is adhered as described above, that is, the adhesive layer (Y) after photo (main) curing, particularly preferably has a crosslinked structure based on the present resin composition, from the viewpoint of the reliability of the anti-foaming property.

In particular, the adhesive layer (Y) is preferably formed using a (meth) acrylate copolymer having an active energy ray-curable moiety, a compound having a chemical bond based on a (meth) acrylate (co) polymer (a) having a functional group (i) and a functional group (ii) reactive with the functional group (i), and a polyfunctional (meth) acrylate having 3 or more functions unmodified with alkylene oxide, as described above, and has a crosslinked structure derived from these compounds.

Description of terms, etc

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

In addition, the term "panel" as used herein includes a plate, a sheet, and a film, for example, in the case of an image display panel, a protective panel, and the like.

In the present invention, when "X to Y" (X, Y is an arbitrary number), the meaning of "X or more and Y or less" is included, and the meaning of "preferably more than X" or "preferably less than Y" is also included, unless otherwise specified.

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

Examples

The following examples are described in further detail. However, the present invention is not limited to the examples described below.

< example > comparative example

Materials used in examples and comparative examples will be described.

(Photocurable adhesive sheet Y)

As the (meth) acrylate (co) polymer, a copolymer prepared from isobornyl methacrylate: methyl methacrylate ═ 1: 1 (mass average molecular weight: 16 ten thousand) obtained by random copolymerization of 13.5 parts by mass of a macromonomer (number average molecular weight 3000) having a terminal functional group of a methacryloyl group, 43.7 parts by mass of lauryl acrylate, 40 parts by mass of 2-ethylhexyl acrylate, and 2.8 parts by mass of acrylamide.

To 1kg of the acrylic graft copolymer, 90g of propoxylated pentaerythritol triacrylate (NK ester ATM-4PL, manufactured by Mitsumura chemical Co., Ltd.) as a crosslinking agent and 15g of a mixture containing a cleavage-type visible light initiator (2,4, 6-trimethylbenzoyl-diphenyl-phosphine oxide, oligo (2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) acetone), 2,4, 6-trimethylbenzophenone and 4-methylbenzophenone (Esacure KTO46, manufactured by Lamberti Co., Ltd.) as a visible light initiator were added and mixed uniformly to obtain a photocurable composition.

Subsequently, the photocurable composition was formed into a sheet shape so that the thickness thereof became 150 μm on a polyethylene terephthalate film (Mitsubishi resin, DIAFOILMRV, thickness 100 μm) whose surface was subjected to a release treatment, and the surface-treated polyethylene terephthalate film (Mitsubishi resin, DIAFOIL MRQ, thickness 75 μm) was covered with the sheet, thereby producing a photocurable adhesive sheet Y1 with a release film.

The photocurable adhesive sheet Y1 is an adhesive sheet having photocurability and cured by irradiation with light.

(resin Member X)

The resin member (X) used was a polycarbonate resin plate (Ilpilon Sheet MR58, product of Mitsubishi gas chemical) containing an ultraviolet absorber, and had a thickness of 1.0mm (used in the pasting composition P) and 1.5mm (used in the pasting composition Q and the pasting composition R).

The transmittance at 365nm was 0% and the transmittance at 405nm was 83% for all the thicknesses.

(Photocurable adhesive sheet laminate)

A release film on one side of the photocurable adhesive sheet Y1 with a release film was peeled off, and the sheet was roll-bonded to one side of the polycarbonate plate (resin member X) to obtain a photocurable adhesive sheet laminate (also referred to as "X/Y1 laminate") of a resin member (X)/photocurable adhesive sheet Y1.

[ example 2]

A photocurable adhesive sheet Y2 and an X/Y2 laminate were obtained in the same manner as in example 1, except that the type of the crosslinking agent in the photocurable adhesive sheet Y was changed to pentaerythritol triacrylate (NK ester ATMM3, manufactured by shinkamura chemical industries, ltd.) and the number of parts added was changed to 70g per 1kg of the acrylic graft copolymer.

The photocurable adhesive sheet Y2 is an adhesive sheet having photocurability and cured by irradiation with light.

[ example 3]

The composition of the (meth) acrylic copolymer of the photocurable adhesive sheet Y is changed to a (meth) acrylic copolymer having an active energy ray-crosslinkable structural moiety with a carbon-carbon double bond, which is obtained by: for a copolymer prepared from isobornyl methacrylate: methyl methacrylate ═ 1: a photocurable adhesive sheet Y3 and an X/Y3 laminate were obtained in the same manner as in example 1, except that 100 parts by mass of a hydroxyl-containing acrylic graft copolymer (mass-average molecular weight: 16 ten thousand) obtained by random copolymerization of 12.7 parts by mass of a macromonomer (number-average molecular weight 3000) having a terminal functional group of a methacryloyl group, 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 was subjected to addition reaction. The photocurable adhesive sheet Y3 is an adhesive sheet having photocurability and cured by irradiation with light.

[ example 4]

As the photocurable adhesive sheet, an adhesive sheet obtained as follows was used: methyl phenylglyoxylate (Irgacure MBF, product of BASF Co., Ltd.) as a hydrogen abstraction type visible light initiator was used as the visible light initiator, and the cumulative light amount at 405nm was previously 100 (mJ/cm)²) A photocurable adhesive sheet Y4 and an X/Y4 laminate were obtained in the same manner as in example 1, except that the sheet was irradiated with light and cured (crosslinked) once.

The photocurable adhesive sheet Y4 is an adhesive sheet having photocurability and cured by irradiation with light.

[ example 5]

As the (meth) acrylate (co) polymer, a (meth) acrylate (co) polymer prepared from isobornyl methacrylate: methyl methacrylate ═ 1: a photocurable pressure-sensitive adhesive sheet Y5 and an X/Y5 laminate were obtained in the same manner as in example 1, except that 13.5 parts by mass of a macromonomer (number average molecular weight 3000) having a methacryloyl group as a terminal functional group, 73.7 parts by mass of 2-ethylhexyl acrylate, 2.8 parts by mass of acrylamide and 10 parts by mass of methyl acrylate were randomly copolymerized to obtain an acrylic graft copolymer (mass average molecular weight: 26 ten thousand), the type of the crosslinking agent was changed to pentaerythritol triacrylate (NK ester ATMM3L, manufactured by Mizhonghamu chemical Co., Ltd.), and the compounding ratio was changed to 70g per 1kg of the acrylic graft copolymer.

The photocurable adhesive sheet Y5 is an adhesive sheet having photocurability and cured by irradiation with light.

[ example 6]

A photocurable pressure-sensitive adhesive sheet Y6 and an X/Y6 laminate were obtained in the same manner as in example 5, except that the amount of the crosslinking agent added was changed to 120g based on 1kg of the acrylic graft copolymer.

The photocurable adhesive sheet Y6 is an adhesive sheet having photocurability and cured by irradiation with light.

[ example 7]

A photocurable pressure-sensitive adhesive sheet Y7 and an X/Y7 laminate were obtained in the same manner as in example 5, except that pentaerythritol triacrylate (manufactured by Ningmura chemical Co., Ltd., NK ester ATMM3L) and dipentaerythritol tetraacrylate (manufactured by Ningmura chemical Co., Ltd., NK ester A9570W) were used in combination in an amount of 90g and 30g, respectively, based on 1kg of the acrylic graft copolymer.

The photocurable adhesive sheet Y7 is an adhesive sheet having photocurability and cured by irradiation with light.

[ example 8]

A photocurable pressure-sensitive adhesive sheet Y8 and an X/Y8 laminate were obtained in the same manner as in example 5, except that pentaerythritol triacrylate (manufactured by Ningmura chemical Co., Ltd., NK ester ATMM3L) and dipentaerythritol tetraacrylate (manufactured by Ningmura chemical Co., Ltd., NK ester A9570W) were used in combinations of 120g and 40g, respectively, based on 1kg of the acrylic graft copolymer.

The photocurable adhesive sheet Y8 is an adhesive sheet having photocurability and cured by irradiation with light.

[ example 9]

As the (meth) acrylic copolymer, a copolymer composed of isobornyl methacrylate: methyl methacrylate ═ 1: 1kg of an acrylic graft copolymer (mass-average molecular weight: 26 ten thousand) obtained by random copolymerization of 13.5 parts by mass of a macromonomer (number-average molecular weight 3000) having a terminal functional group of a methacryloyl group, 73.7 parts by mass of 2-ethylhexyl acrylate, 2.8 parts by mass of acrylamide and 10 parts by mass of methyl acrylate, 75g and 25g of pentaerythritol triacrylate (manufactured by Nizhonghamu chemical industries, Ltd., NK ester ATMM3L) and dipentaerythritol tetraacrylate (manufactured by Nizhonghamu chemical industries, Ltd., NK ester A9570W) as crosslinking agents were used in combination, and 2,4, 6-trimethylbenzoyl-diphenyl-phosphine oxide, oligo (2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) acetone) as a mixture containing a cleavage-type visible light initiator and a visible light initiator were added, A photocurable composition was obtained by uniformly mixing 15g of a mixture of 2,4, 6-trimethylbenzophenone and 4-methylbenzophenone (Esacure KTO46, manufactured by Lamberti Co., Ltd.) and 2g of 3-glycidoxypropyltrimethoxysilane (Shin-Etsu Silicon Co., Ltd., KBM403, manufactured by Ltd.) as a silane coupling agent.

Then, the photocurable composition was formed into a sheet shape with a thickness of 25 μm on a polyethylene terephthalate film (manufactured by Mitsubishi chemical corporation, DIAFOIL MRV, thickness 100 μm) whose surface was subjected to a peeling treatment, and the surface-peeled polyethylene terephthalate film (manufactured by Mitsubishi chemical corporation, DIAFOILMRQ, thickness 75 μm) was covered with the sheet, thereby producing a pressure-sensitive adhesive sheet Y9a for front and back layers with a release film.

1kg of an acrylic graft copolymer (meth) acrylic copolymer) as the same as that used for the pressure-sensitive adhesive sheet Y9a for front and back layers was uniformly mixed with 30g of pentaerythritol triacrylate (NK ester ATMM3L, product of Nippon Korea chemical Co., Ltd.) as a crosslinking agent, and 15g of a mixture containing a cleavage-type visible light initiator (2,4, 6-trimethylbenzoyl-diphenyl-phosphine oxide, oligo (2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) acetone), 2,4, 6-trimethylbenzophenone, and 4-methylbenzophenone (Esacure KTO46, product of Lamberti Co., Ltd.) as a visible light initiator to obtain a photocurable composition.

Then, the photocurable composition was formed into a sheet shape so that the thickness thereof became 100 μm on a polyethylene terephthalate film whose surface was subjected to a peeling treatment (manufactured by Mitsubishi chemical corporation, DIAFOIL MRV, thickness 100 μm), and the surface-peeled polyethylene terephthalate film (manufactured by Mitsubishi chemical corporation, DIAFOILMRQ, thickness 75 μm) was covered with the sheet, thereby producing an adhesive sheet Y9b for an intermediate layer with a release film.

The PET films on both sides of the intermediate adhesive sheet Y9b were sequentially peeled off and removed, and the adhesive surfaces of 2 front and back adhesive sheets Y9a were sequentially bonded to both surfaces of the intermediate adhesive sheet Y9b, to obtain a photocurable adhesive sheet Y9 as a 2-layer 3-layer laminate (total thickness 150 μm) formed of (front and back adhesive sheet Y9 a)/(intermediate adhesive sheet Y9 b)/(front and back adhesive sheet Y9a), and an X/Y9 laminate was obtained in the same manner as in example 1.

[ example 10]

The (meth) acrylic copolymer used in the pressure-sensitive adhesive sheet Y9b for an intermediate layer was changed to one composed of isobornyl methacrylate: methyl methacrylate ═ 1: 1 (number average molecular weight 3000)13.5 parts by mass of a macromonomer having a terminal functional group of a methacryloyl group, 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: 16 ten thousand) to form a pressure-sensitive adhesive sheet Y10b for an intermediate layer, and a photocurable pressure-sensitive adhesive sheet Y10 and an X/Y10 laminate, which were 2 kinds of 3-layer laminates (total thickness 150 μm) formed from (pressure-sensitive adhesive sheet Y9 a)/(pressure-sensitive adhesive sheet Y10b for an intermediate layer)/(pressure-sensitive adhesive sheet Y9a for a front and back layer), were obtained in the same manner as in example 9.

The photocurable adhesive sheet Y10 is an adhesive sheet having photocurability and cured by irradiation with light.

Comparative example 1

A photocurable adhesive sheet Y11 and an X/Y11 laminate were obtained in the same manner as in example 1, except that a mixture of 2,4, 6-trimethylbenzophenone and 4-methylbenzophenone (available from Lamberti corporation) as a hydrogen abstraction type initiator was used as the photoinitiator.

Comparative example 2

A photocurable pressure-sensitive adhesive sheet Y12 and an X/Y12 laminate were obtained in the same manner as in example 1, except that a hydrogen abstraction type initiator, i.e., 1- [4- (4-benzoylphenylsulfonyl) phenyl ] -2-methyl-2- (4-methylphenylsulfonyl) propan-1-one (manufactured by Lamberti, Esacure1001M) was used as the photoinitiator.

Comparative example 3

A photocurable pressure-sensitive adhesive sheet Y13 and an X/Y13 laminate were obtained in the same manner as in example 1, except that a commercially available non-curable optically transparent pressure-sensitive adhesive sheet that did not exhibit photocuring was used as the photocurable pressure-sensitive adhesive sheet.

Comparative example 4

A photocurable adhesive sheet Y14 and an X/Y14 laminate were obtained in the same manner as in example 1, except that a polycarbonate-based resin sheet (thickness of 1.0mm, light transmittance at 365nm of 45%, and light transmittance at 405nm of 91%) containing no ultraviolet absorber was used as the resin member X.

< evaluation >

The method of evaluation described in this specification will be described.

(1) Dynamic storage modulus (G')

For the photocurable adhesive sheets Y1 to Y14 (without release films) having a thickness of 150 μm obtained in examples and comparative examples, 8 sheets were stacked to 1200 μm, and the resultant was measured by a rheometer (MARS, manufactured by k & lten & gton & ltm & gt) using a dynamic viscoelasticity measuring apparatus, and subjected to a pressure sensitive adhesive bonding process in a bonding jig: Φ 25mm parallel plate, strain: 0.5%, frequency 1Hz, temperature rise rate: the measurement was carried out at 3 ℃ per minute.

(2) Spectral transmittance

The resin member (X) was measured for its spectral transmittance (% T) at a wavelength of 300nm to 800nm with a spectrophotometer (UV 2000, Shimadzu corporation). The spectral transmittance was defined as light transmittance.

(3) Gel fraction

The photocurable adhesive sheets Y1 to Y14 (no release films) obtained in examples and comparative examples were each packaged in a bag form using a SUS sieve (#200) with the mass (X) measured in advance, the bag mouth was folded and sealed, the mass (Y) of the bag was measured, the bag was immersed in 100ml of ethyl acetate, the bag was stored in the dark at 23 ℃ for 24 hours, the bag was taken out, the bag was heated at 70 ℃ for 4.5 hours to evaporate the attached ethyl acetate, the mass (Z) of the dried bag was measured, and the mass obtained was substituted into the following formula to obtain the gel fraction X1.

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

In addition, the X/Y1-Y14 laminates obtained in examples and comparative examples were each set to 3000 (mJ/cm) at a cumulative light quantity at 405nm from the resin member (X) side by a high-pressure mercury lamp²) After the light irradiation in the above-described manner, a sample was taken from the adhesive layer portion on the resin member (X) side surface of the photocurable adhesive sheet, and the gel fraction X2 was determined in the same manner as described above. Then, X2-X1 were calculated.

(4) Height difference absorbency

A glass plate having a central recess 52mm x 80mm and having a printing height difference was prepared by printing a glass plate having a thickness of 22 to 24 μm on the peripheral edge (3 mm on the long side and 15mm on the short side) of a glass plate having a thickness of 58mm x 110mm x 0.8 mm.

One release film was peeled off from each of the photocurable adhesive sheets with release films Y1 to Y14 obtained in examples and comparative examples, and after roll-bonding the sheets on the entire surface of soda-lime glass (54mm × 82mm × 0.5mm in thickness), the remaining release film was peeled off, and vacuum pressure bonding was performed by vacuum pressing (temperature 25 ℃, pressing pressure 0.13MPa) so that the adhesive sheet covered the frame-shaped printing height difference of the glass plate with printing height difference, thereby preparing an evaluation sample.

The evaluation samples were autoclaved at 60 ℃ under 0.2MPa for 20 minutes, and then judged to be acceptable or not according to the following evaluation standards.

○ (good) no fine bubbles were observed at the periphery of the height difference

X (por): minute bubbles were visible around the level difference

(5) Yellow Index (YI)

The X/Y1-Y14 layered products obtained in examples and comparative examples were respectively provided with a cumulative light quantity at 405nm of 3000 (mJ/cm) from the resin member (X) side by a high-pressure mercury lamp²) The light is irradiated.

The cumulative light amount at 405nm is the cumulative light amount which is measured by an ultraviolet cumulative light amount meter "UIT-250" (manufactured by USHIO INC.) and a light receiver "UVD-C405" (manufactured by USHIO INC.) by providing a light amount meter on the surface of the resin member (X) opposite to the surface irradiated with the high-pressure mercury lamp, and which is irradiated to the photocurable adhesive sheets (Y1-Y14) through the resin member (X).

Thereafter, the Yellowness (YI) of the X/Y1 to Y14 laminates was measured with a spectrophotometer (Suga Test Instruments co., Ltd.) "SC-T" based on jis k7103, and the acceptability was determined based on the following evaluation criteria.

○ (good) with YI less than 2

X (por): YI is 2 or more

(6) UV resistant reliability (Δ YI)

The X/Y1-Y14 laminates obtained in examples and comparative examples were measured from the resin member (X) side using a high-pressure mercury lamp, and the cumulative light quantity at 405nm was 3000 (mJ/cm)²) The light is irradiated.

Then, the resultant was irradiated with a UVB fluorescent lamp (G15T8E Co., Ltd.)Illuminance of 70 muW/cm²) An irradiation test was carried out at a distance of 20cm for 72 hours.

Whether or not the laminates were acceptable was judged by the following evaluation criteria based on the change Δ YI in the Yellowness (YI) of the X/Y1 to Y14 laminates before and after irradiation.

○ (good): Delta YI less than 0.2

X (por): delta YI of 0.2 or more

(7) Reliability of resistance to foaming

With respect to the X/Y laminates obtained in examples and comparative examples, the other release film remaining on the Y surface side was peeled off, and the following 3 kinds of members were attached to the exposed surface with a hand roller, and the reliability of foam resistance at the time of attachment was evaluated.

The X/Y laminate was cut into the size of each member and used.

Specific sticking configurations are 3 types of X/Y laminate/member P (sticking configuration P), X/Y laminate/member Q (sticking configuration Q), and X/Y laminate/member R (sticking configuration R).

A member P: soda-lime glass 54mm × 82mm × thickness 0.55mm

A member Q: soda-lime glass 100mm x 180mm x thickness 0.55mm

Component R PET film 100mm x 180mm x thickness 100 μm

The members P (adhering structures P) were completely adhered by autoclave treatment at 60 ℃ and 0.2MPa for 30 minutes, and the members Q and R (adhering structures Q and R) were completely adhered by autoclave treatment at 80 ℃ and 0.2MPa for 30 minutes.

After the completion of the above-mentioned adhesion, the cumulative light quantity at 405nm from the resin member (X) side was 3000 (mJ/cm) using a high-pressure mercury lamp²) The test piece was irradiated with light to prepare a sample for evaluating reliability of foaming resistance.

The evaluation samples were exposed to 85 ℃ and 85% r.h. environment for 24 hours, and the samples were judged as "○ (good)" when no appearance defects such as foaming and peeling were observed, and "x (color)" when foaming and peeling were observed.

Further, the overall judgment of the sticking composition P or Q (single-sided glass member) and the sticking composition R (double-sided resin member) was "◎ (very good)", the overall judgment of either one of the sticking compositions P, Q and R was "good" (good) ", and the overall judgment of both the sticking compositions P, Q and R was" x (void) ".

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

After 2 months or more, the photocurable adhesive sheets Y obtained in examples and comparative examples were each prepared, and the release film of the adhesive sheet Y was peeled off and the adhesive surfaces of the exposed both surfaces were stuck with 2 sheets of soda-lime glass (thickness 0.55mm) therebetween, and the cumulative light quantity at 405nm was 3000 (mJ/cm) using a high-pressure mercury lamp²) After irradiation with light, the haze value was measured.

The haze value was measured by a haze meter (NDH 5000, manufactured by nippon electrochromic industries) in accordance with JIS K7136.

A case where the haze value is less than 0.5 is determined as "○ (good)", a case where the haze value is 0.5 or more and less than 1.0 is determined as "△ (satisfactory)", and a case where the haze value is 1.0 or more is determined as "x (port)".

(9) Tg after photocuring

The photocurable adhesive sheets Y1 to Y14 (without release films) having a thickness of 150 μm obtained in examples and comparative examples were each set to a cumulative light amount at 405nm of 3000 (mJ/cm)²) After irradiation with light, 8 photocurable adhesive sheets Y1 to Y14 were stacked up to 1200 μm each, and the resultant was measured by a rheometer (MARS) as a dynamic viscoelasticity measuring apparatus, in a bonding jig: Φ 25mm parallel plate, strain: 0.5%, frequency 1Hz, temperature rise rate: the temperature at which the peak of Tan δ is measured was taken as Tg, and the measured temperature was taken as Tg.

(10) Viscosity of the oil

For the 150 μm photocurable adhesive sheets Y1 to Y14 (without release films) obtained in examples and comparative examples, 8 sheets were stacked to 1200 μm each, and the resultant was measured by a rheometer (MARS, manufactured by k. en) using a dynamic viscoelasticity measuring apparatus, and in a bonding jig: Φ 25mm parallel plate, strain: 0.5%, frequency 1Hz, temperature rise rate: the complex viscosity of the pressure-sensitive adhesive sheet before photocuring at 70 ℃ and 100 ℃ was measured at 3 ℃/min.

(11) Keeping property

Photocurable adhesive sheets Y1 to Y14 cut into squares of 50mm × 50mm were sandwiched between 2 PET films each 100mm × 100mm square and 100 μm thick to prepare a laminate, and after standing at 23 ℃ for 300 hours in an environment of 50%, visual observation was made as to whether or not the adhesive had oozed out of the laminate.

When the laminate was visually observed, the case where the adhesive was oozed out entirely was judged as "x (port)", the case where the adhesive was oozed out only at the corners was judged as "△ (satisfactory)", and the case where the adhesive was not oozed out was judged as "○ (good)".

[ Table 1]

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The photocurable adhesive sheet laminates (X/Y1 to Y10 laminates) of the resin member (X)/photocurable adhesive sheet (Y1 to Y10) of examples 1 to 10 had a cumulative light amount at a wavelength of 405nm of 3000 (mJ/cm) from the resin member (X) side²) When irradiated with light in the above-mentioned manner, the photocurable adhesive sheets Y1 to Y10 were sufficiently cured to improve the difference in gel fraction by 10% or more, and the dynamic storage modulus (G') was maintained at 0.7X 10 at 120 ℃ and 1Hz⁴Pa or more, and therefore, good reliability of foaming resistance is obtained. In particular, in a test assuming that the touch sensor is a glass sensor, good reliability against foaming is obtained.

Wherein, for examples 3, 7, 9 and 10, the dynamic storage modulus (G') was maintained at 120 ℃ and 1Hz at 2.0X 10⁴Pa or more, and therefore, good reliability against foaming is obtained also in a test assuming that the touch sensor is a thin film sensor.

In example 8, although good reliability against foaming was obtained in the test assuming that the touch sensor was a thin film sensor, glass peeling occurred in the test assuming that the touch sensor was a glass sensor. This is considered to be because the dynamic storage modulus (G') becomes excessively high at 120 ℃ and 1Hz, and the viscosity and the adhesive property are lowered.

In example 2, since the content of the hydrophilic monomer constituting the (meth) acrylate (co) polymer (a) was 10 parts by mass or less, the phase separation proceeded during long-term storage, and the haze after long-term storage was "△ (satisfactory)".

It is considered that in examples 1 to 10, the height difference absorbing property was good, and the cover member having the printed height difference was also durable in practical use depending on the type of the touch sensor.

In examples 4, 9 and 10, the viscosity (70 ℃ C.) was as high as 1.5kPa · s or more, and therefore no bleeding of the gel was observed even after long-term storage, and the storage stability was excellent.

In comparative examples 1 and 2, the light transmittance (%) of the photocurable adhesive sheets Y11 and Y12 at a wavelength of 390nm was as high as 90% or more, and the cumulative amount of light at a wavelength of 405nm from the resin member (X) side was 3000 (mJ/cm)²) In the method (3), excitation by light absorption of the photoinitiator and progress of the curing (crosslinking) reaction are insufficient when light is irradiated, and therefore, the adhesive layer (Y) cannot be sufficiently cured, and bubbles are generated in the foaming resistance reliability test.

In comparative example 3, the gel fraction of the photocurable adhesive sheet Y13 was 88%, and the dynamic storage modulus (G') (25 ℃ C.) was as high as 1.1X 10⁵Pa, and therefore, the height difference absorption property is poor, and bubbles are generated.

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

Claims

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

(1) the gel fraction (referred to as "gel fraction X1 before light irradiation") is in the range of 0-60%;

(2) a light transmittance at a wavelength of 390nm of 89% or less and a light transmittance at a wavelength of 410nm of 80% or more;

2. The photocurable adhesive sheet according to claim 1, wherein the photocurability in (3) is a photocurability which is improved by 10% or more in terms of a difference in gel fraction when irradiated with light having a wavelength of 405 nm.

3. The photocurable adhesive sheet according to claim 1, which has the following photocurability: the cumulative light quantity at an irradiation wavelength of 405nm was 3000 (mJ/cm)²) In the case of (1), the difference between the gel fraction after light irradiation (referred to as "gel fraction after light irradiation X2") and the gel fraction before light irradiation (gel fraction before light irradiation X1) (gel fraction after light irradiation X2-gel fraction before light irradiation X1) is 10% or more.

4. A photocurable adhesive sheet according to any one of claims 1-3, wherein said adhesive layer (Y) contains a (meth) acrylate (co) polymer and a visible light initiator.

5. The photocurable adhesive sheet according to any one of claims 1 to4, wherein the adhesive layer (Y) contains a silane coupling agent.

6. The photocurable adhesive sheet according to claim 4 or 5, wherein the (meth) acrylate (co) polymer is formed with a chemical bond based on a combination of any functional group selected from the group consisting of carboxyl group and epoxy group, carboxyl group and aziridine group, hydroxyl group and isocyanate group, amino group and isocyanate group, and carboxyl group and isocyanate group.

7. The photocurable adhesive sheet according to claim 4 or 5, wherein the (meth) acrylate (co) polymer is a graft copolymer having a macromonomer as a branch component.

8. A photocurable adhesive sheet according to any one of claims 4 to 7, wherein said visible light initiator is a hydrogen-abstraction type visible light initiator.

9. The photocurable adhesive sheet according to claim 8, wherein the hydrogen abstraction-type visible light initiator is any 1 or 2 selected from the group consisting of methyl phenylglyoxylate, a mixture of oxy-phenyl-acetic acid 2- [ 2-oxo-2-phenyl-acetoxy-ethoxy ] ethyl ester and oxy-phenyl-acetic acid 2- [ 2-hydroxy-ethoxy ] ethyl ester.

10. The photocurable adhesive sheet according to any one of claims 4 to 9, wherein the (meth) acrylate (co) polymer is a copolymer containing, as copolymerization components, a linear or branched alkyl (meth) acrylate having a side chain of 4 to 18 carbon atoms and a hydrophilic (meth) acrylate.

11. The photocurable adhesive sheet according to any one of claims 1 to 10, wherein the adhesive layer (Y) contains a crosslinking agent or is formed using a crosslinking agent.

12. The photocurable adhesive sheet according to claim 11, wherein the crosslinking agent is an alkylene oxide-unmodified 3-or more-functional polyfunctional (meth) acrylate.

13. A photocurable adhesive sheet according to any one of claims 4 to 12, wherein said (meth) acrylate (co) polymer has an active energy ray-crosslinkable structural moiety.

14. The photocurable adhesive sheet according to any one of claims 1-13, wherein the storage modulus (G') is 0.9 x 10 at a temperature of 25 ℃ and a frequency of 1Hz⁵Pa or less.

15.The photocurable adhesive sheet according to any one of claims 1 to 14, wherein the cumulative light amount at an irradiation wavelength of 405nm is 3000 (mJ/cm)²) The storage modulus (G') of the adhesive layer (Y) after irradiation with light is 0.7X 10 at a temperature of 120 ℃ and a frequency of 1Hz⁴Pa or above.

16. The photocurable adhesive sheet according to any one of claims 1 to 14, wherein the cumulative light amount at an irradiation wavelength of 405nm is 3000 (mJ/cm)²) The storage modulus (G') of the adhesive layer (Y) after irradiation with light is 2.0X 10 at a temperature of 120 ℃ and a frequency of 1Hz⁴Pa or above.

17. The photocurable adhesive sheet according to any one of claims 1 to 16, wherein the adhesive layer (Y) has a hot-melt property that softens or flows when heated.

18. A photocurable adhesive sheet according to any one of claims 1 to 17, wherein the adhesive sheet is used for bonding a resin member (X) having a light transmittance at a wavelength of 365nm of 10% or less and a light transmittance at a wavelength of 405nm of 60% or more.

19. A photocurable adhesive sheet laminate comprising: a photocurable adhesive sheet according to any one of claims 1 to 17, having a structure in which a resin member (X) having a light transmittance at a wavelength of 365nm of 10% or less and a light transmittance at a wavelength of 405nm of 60% or more is laminated.

20. The photocurable adhesive sheet laminate according to claim 19, wherein the photocurable adhesive sheet has a single-layer or 2-or more-layer structure, has a gel fraction (referred to as "gel fraction before light irradiation X1") of 0 to 60% with respect to the adhesive layer (Y) on the surface of the single-layer or multi-layer resin member (X), and has a photocurability that is improved by 10% or more in terms of the difference in gel fraction when light having a wavelength of 405nm is irradiated from the outside of the resin member (X) through the resin member (X).

21. The photocurable adhesive sheet laminate according to claim 19 or 20, wherein the adhesive layer (Y) of the photocurable adhesive sheet has a photocurability of: a cumulative light quantity at an irradiation wavelength of 405nm of 3000 (mJ/cm) from the outside of the resin member (X) through the resin member (X)²) In the case of (1), the difference between the gel fraction after light irradiation (referred to as "gel fraction after light irradiation X2") and the gel fraction before light irradiation (gel fraction before light irradiation X1) (gel fraction after light irradiation X2-gel fraction before light irradiation X1) is 10% or more.

22. A photocurable adhesive sheet laminate according to any one of claims 19 to 21, wherein said resin member (X) is a member containing a polycarbonate-based resin or an acrylic-based resin as a main component resin.

23. The photocurable adhesive sheet laminate according to any one of claims 19 to 22, wherein a cumulative light amount at 405nm of irradiation from the outside of the resin member (X) through the resin member (X) is 3000 (mJ/cm)²) In the case of (3), the storage modulus (G') of the adhesive layer (Y) in the photocurable adhesive sheet after light irradiation is 0.7X 10 at a temperature of 120 ℃ and a frequency of 1Hz⁴Pa or above.

24. A photocurable adhesive sheet laminate according to any one of claims 19 to 23, wherein a cumulative light amount at 405nm of 3000 (mJ/cm) is irradiated from outside of the resin member (X) through the resin member (X)²) When the storage modulus (G') of the adhesive layer (Y) in the photocurable adhesive sheet after light irradiation is 2.0X 10 at a temperature of 120 ℃ and a frequency of 1Hz⁴Pa or above.

25. A method for producing a photocurable adhesive sheet laminate according to any one of claims 19 to 24,

the method for producing a photocurable adhesive sheet comprises producing the photocurable adhesive sheet from a resin composition containing a (meth) acrylate (co) polymer and a visible light initiator, and laminating the photocurable adhesive sheet on the resin member (X).

26. A method for manufacturing an image display panel laminate, the method comprising: the photocurable adhesive sheet laminate according to any one of claims 19 to 24, which is formed by bonding an image display panel (P) to a photocurable adhesive sheet,

in the manufacturing method, a resin member (X) and an image display panel (P) are laminated through the light-curing adhesive sheet,

the adhesive layer (Y) of the photocurable adhesive sheet is cured by irradiating light having a wavelength of 405nm from the outside of the resin member (X) through the resin member (X), and the resin member (X) is bonded to the image display panel (P).