JP7151518B2 - Photo-curing adhesive sheet, photo-curing adhesive sheet with release sheet, optical film with photo-curing adhesive sheet, laminate for constituting image display device, and image display device - Google Patents

Description

The present invention provides a photocurable pressure-sensitive adhesive sheet excellent in metal corrosion resistance, low-temperature adhesive properties, workability, etc., and a photocurable pressure-sensitive adhesive sheet with a release sheet and a photocurable pressure-sensitive adhesive sheet using the same. The present invention relates to an optical film, a laminate for constituting an image display device, and an image display device.

In recent years, in order to improve the visibility of an image display device, an image display panel such as a liquid crystal display (LCD), a plasma display (PDP), an organic EL (electroluminescence) display, and the front side (viewing side) thereof are arranged. The gap between the protective panel and the touch panel member is filled with an adhesive or adhesive sheet to suppress the reflection of incident light or emitted light from the display image at the interface of the air layer.

As such conventional pressure-sensitive adhesive sheets, acrylic pressure-sensitive adhesive sheets such as those exemplified in Patent Documents 1 to 5 have been used.

For example, the touch panel member usually includes an upper electrode plate and a lower electrode plate having fine wiring and a transparent conductive layer formed of a metal material such as tin-doped indium oxide (ITO). Therefore, excellent corrosion resistance to these metallic materials is required.

Therefore, for example, in Patent Document 6, as a pressure-sensitive adhesive sheet that can suppress the occurrence of undulations and can efficiently and at low cost produce an optical member excellent in corrosion prevention effect while maintaining a high level of adhesion reliability and transparency, a base polymer and The base polymer does not contain or substantially does not contain an acidic group-containing monomer as a constituent monomer component, and has an elastic modulus at 85° C. of 5.0×10 ⁴ Pa or more. Disclosed is a pressure-sensitive adhesive sheet having an optical pressure-sensitive adhesive layer characterized by:

Further, in Patent Document 7, even when an adherend that generates outgassing in a high-temperature environment, such as a polycarbonate plate or an acrylic plate, is used as an adherend, foaming and floating peeling occurring at the adhesion interface are suppressed, and at the same time, metal A transparent adhesive tape capable of suppressing deterioration of a thin film has an adhesive layer made of an adhesive composition containing a (meth)acrylic acid ester copolymer as a main component, and the adhesive layer has a frequency of 10 Hz. The loss tangent of the dynamic viscoelastic spectrum at has a maximum value in the temperature range of −20 to 20° C., the shear storage modulus at 200° C. is 2.5×10 ⁴ Pa or more, and the gel A transparent adhesive tape characterized by a fraction of 70% by weight or more is disclosed.

Furthermore, in Patent Document 8, as an optical pressure-sensitive adhesive sheet having excellent whitening resistance, excellent adhesion reliability at high temperatures, and excellent step absorption, the glass transition temperature when forming a homopolymer is -10 ° C. or higher. and an acrylic pressure-sensitive adhesive layer having a shear storage elastic modulus of 0.8×10 ⁵ to 5.0×10 ⁵ Pa at 23° C. and a moisture content of 0.65% by weight or more after being stored in an environment of 60° C. and 95% RH for 120 hours.

WO2010/044229 WO2011/129200 WO2012/032995 WO2013/008565 WO2015/080097 JP 2015-004048 A WO2012/173247 WO2011/111575

As disclosed in Patent Documents 6 to 8 above, from the viewpoint of preventing corrosion and deterioration of metal thin films and the like caused by adhesive sheets, it is necessary to avoid using monomer components having acidic groups such as acrylic acid as adhesive sheet-forming materials as much as possible. It has been demanded.
In addition, since a monomer component having an acidic group is not substantially used, it is inevitable to use a monomer component having a hydroxyl group or a monomer component having a nitrogen atom in order to improve the whitening resistance and adhesive strength of the pressure-sensitive adhesive sheet. do not have.

Furthermore, under the above material restrictions, it is necessary to adjust the elastic modulus at room temperature within a predetermined range in order to prevent glue from oozing out, absorb unevenness, and prevent the occurrence of air bubbles and floats during lamination. , For example, as in Patent Document 8, the loss tangent of dynamic viscoelasticity ( Techniques have been proposed to set the glass transition temperature (Tg) of the PSA sheet relatively high, which is defined by the peak temperature of Tan δ).
However, if the glass transition temperature (Tg) of the adhesive sheet is set relatively high, the adhesive properties at low temperatures become inferior, resulting in poor impact resistance when used in winter and cold regions. was to occur.
In addition, as in Patent Document 7, even when the storage modulus of the adhesive sheet is set extremely high, the adhesive properties at low temperatures are reduced, and as a result, the adhesive sheet may peel off when dropped or may be peeled off at low temperatures in winter. Problems such as peeling due to a decrease in adhesive strength have arisen when used in an environment.

In addition, with the expansion of display screens, for example, adhesive sheets used in image display devices such as mobile phones have been made into complicated and fine shapes, such as by punching circular portions where cameras, buttons, microphones, etc. are provided. Punching workability that allows punching is required.

Accordingly, it is an object of the present invention to provide a new pressure-sensitive adhesive sheet that has corrosion resistance to metals, excellent low-temperature pressure-sensitive adhesive properties, and punchability.

The present invention is formed from a pressure-sensitive adhesive resin composition containing a (meth)acrylic copolymer (A) and has two or more continuous layers of pressure-sensitive adhesive having different shear storage elastic moduli (G') at a temperature of 25°C. agent layer, the (meth)acrylic copolymer (A) substantially does not contain structural units derived from a carboxyl group-containing (meth)acrylate monomer, and a monomer component constituting the copolymer As, any one or more polar group-containing (meth)acrylate monomers (a2) selected from the group consisting of hydroxyl group-containing (meth)acrylate monomers and nitrogen atom-containing (meth)acrylate monomers, and (a2) other than and a low Tg (meth)acrylate monomer (a1) having a glass transition temperature (Tg) of less than −30° C. when a homopolymer is formed from the monomer components, and the pressure-sensitive adhesive sheet is sheared at a temperature of 25° C. The storage modulus (G′) is 100 kPa or more and 500 kPa or less, and the glass transition temperature (Tg) defined by the peak temperature of the loss tangent (Tan δ) obtained by dynamic viscoelasticity measurement is 0° C. or less. We propose a photocurable pressure-sensitive adhesive sheet characterized by:

Since the adhesive resin composition used for forming the photocurable adhesive sheet of the present invention substantially does not contain a carboxyl group-containing (meth)acrylate as a monomer component having an acidic group, the photocurable adhesive sheet of the present invention The pressure-sensitive adhesive sheet does not substantially contain a structural unit derived from a carboxyl group-containing (meth)acrylate, and can be excellent in metal corrosion resistance.
In addition, since the photocurable pressure-sensitive adhesive sheet of the present invention has a shear storage modulus (G′) of 100 kPa or more and 500 kPa or less at a temperature of 25° C., it has cutting workability, punching workability into complicated shapes, and various adhesive properties. can be combined in a well-balanced manner.
Furthermore, the photocurable pressure-sensitive adhesive sheet of the present invention has a glass transition temperature (Tg) defined by the peak temperature of the loss tangent (Tan δ) obtained by dynamic viscoelasticity measurement of 0 ° C. or less, so that the adhesive at low temperatures It has high strength, does not peel off even when used in winter or in cold regions, and has excellent impact resistance (low-temperature impact resistance) when dropped.

In addition to the above, the photocurable pressure-sensitive adhesive sheet proposed by the present invention has the property of being cured by light (photocurable), so it is flexible and has excellent step absorption before photocuring. In addition, since the cohesive force can be increased by photocuring, the lamination reliability under cold and hot conditions can be excellent.

It is a diagram for explaining the evaluation test method of ITO corrosion resistance reliability and Cu corrosion resistance reliability performed in the examples described later, (A) is a top view of the ITO pattern of the ITO glass substrate or corrosion resistance reliability evaluation Top view of the copper pattern of the copper glass substrate for ITO corrosion resistance reliability evaluation, (B) is a top view showing the state where the adhesive sheet is coated on the ITO glass substrate for evaluation of ITO corrosion resistance reliability, or on the copper glass substrate for evaluation of Cu corrosion resistance reliability (C) is a cross-sectional view of a sample for evaluating ITO corrosion resistance reliability, and (D) is a cross-sectional view of a sample for evaluating Cu corrosion resistance reliability.

<<Photo-curable adhesive sheet>>
A photocurable pressure-sensitive adhesive sheet (hereinafter referred to as "the present pressure-sensitive adhesive sheet") according to an example of the embodiment of the present invention is a pressure-sensitive adhesive resin composition containing a (meth)acrylic copolymer (A) (hereinafter "the present resin A sheet having two or more pressure-sensitive adhesive layers formed from "composition"),
The shear storage modulus (G′) at a temperature of 25° C. is 100 kPa or more and 500 kPa or less, and the glass transition temperature (Tg) defined by the peak temperature of the loss tangent (Tan δ) obtained by dynamic viscoelasticity measurement. (hereinafter referred to as "Tg as a measured value") is 0°C or less.

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

Hitherto, in order to increase the shear storage modulus (G') of the pressure-sensitive adhesive sheet at a temperature of 25°C, the pressure-sensitive adhesive sheet had to be designed to have a high Tg as a measured value.
However, the photocurable pressure-sensitive adhesive sheet of the present invention is a contradiction that "the shear storage modulus (G') at a temperature of 25 ° C. is relatively high and the glass transition temperature (Tg) as a measured value is relatively low." Because of this, it can have both low-temperature impact resistance and punching workability.

As described above, the present pressure-sensitive adhesive sheet has a shear storage modulus (G′) of 100 kPa or more and 500 kPa or less at a temperature of 25° C. In particular, it has a good balance between cutting workability, punching workability into complicated shapes, and various adhesive properties. From the viewpoint of achieving a good balance, it is preferably 110 kPa or more and 400 kPa or less, more preferably 120 kPa or more and 300 kPa or less, and particularly preferably 140 kPa or more and 200 kPa or less.

As described above, the PSA sheet has a measured Tg of 0° C. or less. Among them, from the viewpoint of low-temperature impact resistance when used in winter or in cold regions, the temperature is preferably −5° C. or less, more preferably −10° C. or less, and particularly −15° C. or less. preferable.
Although the lower limit value is not necessarily limited, it is -40°C or higher in reality.

In order for the pressure-sensitive adhesive sheet to adjust the shear storage modulus (G′) at a temperature of 25° C. to the above range and to adjust the Tg as a measured value to the above range, the resin composition described below is used. It is preferable to provide two or more continuous pressure-sensitive adhesive layers. However, it is not limited to this.

<This adhesive layer>
The present pressure-sensitive adhesive sheet has two or more pressure-sensitive adhesive layers formed from the present resin composition (each of these pressure-sensitive adhesive layers is collectively referred to as "the present pressure-sensitive adhesive layer") in order to have the above properties. And, it is preferable that the two or more pressure-sensitive adhesive layers form a continuous superimposed layer.

Above all, the pressure-sensitive adhesive layer in the present pressure-sensitive adhesive sheet has a configuration in which two or more pressure-sensitive adhesive layers having different shear storage elastic moduli (G′) at a temperature of 25° C. are continuously laminated. is preferred.
If the present pressure-sensitive adhesive sheet has such a structure, each pressure-sensitive adhesive layer can be assigned a different function, so that the present pressure-sensitive adhesive sheet can have, for example, contradictory properties as described above.
More specifically, for example, by changing the amount of the cross-linking agent in two consecutive layers to adjust the elastic modulus of each layer, or by changing the composition of each layer to change the glass transition temperature, the present pressure-sensitive adhesive sheet can be obtained. It is possible to realize contradictory properties such as "a relatively high shear storage modulus (G') at a temperature of 25°C and a relatively low glass transition temperature (Tg) as a measured value". In this case, if the adhesive layer is composed only of an adhesive layer having a high elastic modulus, the punching workability is excellent, but the adhesive properties and step absorbability at low temperatures cannot be ensured.
On the other hand, if it is composed only of an adhesive layer with a low Tg, although it has excellent adhesive properties at low temperatures and step absorbability, it has a low elastic modulus and cannot ensure punching workability.
Therefore, by laminating different layers, the first adhesive layer can provide low-temperature adhesive properties and step absorbability, and the second adhesive layer can provide punching workability. can do.

In general, when the pressure-sensitive adhesive sheet is an isotropic elastic body, there is a relationship of E'=3G' between the tensile elastic modulus (E') and the shear storage elastic modulus (G').
However, when the PSA sheet has two or more continuous PSA layers with different shear storage elastic moduli (G′) at a temperature of 25° C., that is, when it is an anisotropic elastic body, The relationship does not hold (E'≠3G').
Therefore, in the present invention, when judging whether or not the present pressure-sensitive adhesive sheet "has two or more continuous pressure-sensitive adhesive layers with different shear storage moduli (G′) at a temperature of 25° C." The tensile modulus (E') at °C and the shear storage modulus (G') at a temperature of 25 °C satisfy the relationship of E'≠3G'.
More specifically, the E'/G' ratio of the pressure-sensitive adhesive sheet is preferably 5 or more, more preferably 7 or more or 100 or less, and still more preferably 10 or more or 30 or less. It has two or more continuous pressure-sensitive adhesive layers with different shear storage elastic moduli (G') at a temperature of 25°C.

<Lamination structure>
As the laminated structure having two or more continuous adhesive layers with different shear storage moduli (G′) at a temperature of 25 ° C., for example, at least one layer (first adhesive A two-layer two-layer configuration in which a layer (adhesive layer) and another layer (second adhesive layer) are continuously laminated, or a first adhesive layer, a second adhesive layer, and a first adhesive layer A two-kind, three-layer configuration in which the first adhesive layer, the second adhesive layer, and the third adhesive layer are continuously laminated, or a three-kind, three-layer configuration in which the first pressure-sensitive adhesive layer, the second pressure-sensitive adhesive layer, and the third pressure-sensitive adhesive layer are continuously laminated. can be done. Among these, a two-kind three-layer structure in which a first pressure-sensitive adhesive layer, a second pressure-sensitive adhesive layer and a first pressure-sensitive adhesive layer are continuously laminated is particularly preferable.
The first pressure-sensitive adhesive layer, the second pressure-sensitive adhesive layer, and the third pressure-sensitive adhesive layer all correspond to the present pressure-sensitive adhesive layer, and are composed of a specific (meth)acrylic copolymer. It is a pressure-sensitive adhesive layer and is a layer having a different modulus of elasticity.

The first pressure-sensitive adhesive layer in this pressure-sensitive adhesive sheet can be defined as a pressure-sensitive adhesive layer forming at least one outermost layer.

The first pressure-sensitive adhesive layer in the laminate structure preferably has a lower shear storage modulus (G') at a temperature of 25°C than the second pressure-sensitive adhesive layer. As a result, it becomes easier to design a material that has cutting workability, punching workability into complicated shapes, and various adhesive properties such as low-temperature properties and adhesive strength in a well-balanced manner.
In order to adjust the shear storage modulus (G') of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer at a temperature of 25°C as described above, the second pressure-sensitive adhesive layer contains a larger amount of the cross-linking agent. , the elastic modulus should be increased. However, it is not limited to this.

In addition, the first pressure-sensitive adhesive layer in the laminate structure preferably has a shear storage modulus (G') at a temperature of 25°C lower than that of the entire pressure-sensitive adhesive sheet. As a result, it becomes easier to design a material that has cutting workability, punching workability into complicated shapes, and various adhesive properties such as low-temperature properties and adhesive strength in a well-balanced manner.
From this point of view, the first pressure-sensitive adhesive layer in the laminated structure preferably has a shear storage modulus (G′) at 25° C. lower than that of the entire pressure-sensitive adhesive sheet by 10 kPa to 500 kPa, especially 30 kPa or more or 300 kPa. In the following, it is even more preferable that the pressure is lower in the range of 100 kPa or more and 200 kPa or less.
In addition, in order to adjust the shear storage modulus (G′) of the first pressure-sensitive adhesive layer and the entire pressure-sensitive adhesive sheet at a temperature of 25° C. as described above, the cross-linking used in the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer The compounding ratio of the agent and the initiator may be adjusted, or the composition of the (meth)acrylic polymer used in each layer may be adjusted. However, it is not limited to this.

(First adhesive layer)
From the above viewpoint, the shear storage modulus (G′) of the first pressure-sensitive adhesive layer at a temperature of 25° C. is preferably 0.1 kPa to 90 kPa, especially 1 kPa or more or 70 kPa or less, especially 10 kPa or more or 50 kPa or less. It is preferable to have
In order to form the first pressure-sensitive adhesive layer in this manner, the compounding ratio of the cross-linking agent and the initiator may be adjusted, or the composition of the (meth)acrylic polymer may be adjusted. However, it is not limited to this.

The first pressure-sensitive adhesive layer preferably has a shear storage modulus (G′) at a temperature of 70° C. of 0.01 kPa or more and 70 kPa or less, more preferably 0.1 kPa or more or 50 kPa or less, from the viewpoint of further improving step absorbability. Among them, it is preferably 0.5 kPa or more or 15 kPa or less.
Similarly, the first pressure-sensitive adhesive layer preferably has a loss tangent (Tan δ) at a temperature of 70° C. of 0.5 or more and 10 or less, especially 0.65 or more or 3 or less, from the viewpoint of further improving step absorbability. Above all, it is more preferably 0.8 or more or 1.3 or less.
In order to form the first pressure-sensitive adhesive layer in this manner, the amount of the cross-linking agent may be adjusted, or the composition of the main component used in the first pressure-sensitive adhesive layer may be adjusted. However, it is not limited to this.

Further, the first pressure-sensitive adhesive layer may have a composition that does not contain an acid or a composition that contains an antirust agent, in order to further improve the metal corrosion resistance.

(Second adhesive layer)
On the other hand, the shear storage modulus (G′) of the second pressure-sensitive adhesive layer at a temperature of 25° C. is preferably 200 kPa to 100 MPa, more preferably 500 kPa or more or 10 MPa or less, and more preferably 1 MPa or more or 6 MPa or less. .
In order to form the second pressure-sensitive adhesive layer in this way, it is necessary to increase the elastic modulus by including a large amount of a cross-linking agent, or to adjust the composition of the main agent used in the second pressure-sensitive adhesive layer to increase the elastic modulus. Just do it. However, it is not limited to this.

Reliability can be improved by using the same resin as that of the first pressure-sensitive adhesive layer for the main agent of the second pressure-sensitive adhesive layer, that is, the (meth)acrylic copolymer (A). That is, the adhesion between the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer is increased, and a higher level of reliability can be ensured.

(other layers)
The pressure-sensitive adhesive sheet can also have "another layer" other than the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer, as described above.

<Thickness ratio>
When the present pressure-sensitive adhesive sheet has the above-described laminated structure, that is, the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer having different shear storage elastic moduli (G′) at a temperature of 25 ° C., the pressure-sensitive adhesive sheet has workability and handling properties. From the viewpoint of imparting a is more preferably 1.5 or more or 5 or less.
In the case of a two-kind three-layer structure in which the first pressure-sensitive adhesive layer, the second pressure-sensitive adhesive layer and the first pressure-sensitive adhesive layer are continuously laminated, the thickness t1 of the first pressure-sensitive adhesive layer is the outermost layer represents the total thickness of the two layers that make up the

<Photocurability>
The present pressure-sensitive adhesive sheet has photocurability, and the term “light” specifically means light in the wavelength range of 200 nm to 780 nm, and the term “photocurability” means curable in such a wavelength range. means to have In order for the pressure-sensitive adhesive sheet to have the photo-curing property, it is sufficient that the pressure-sensitive adhesive sheet has any one of the following pressure-sensitive adhesive layers (1) to (3).
In addition, in the above laminated structure, any one of the pressure-sensitive adhesive layers such as the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer may have photocurability. In particular, from the viewpoint of improving reliability after lamination with an adherend, at least the outermost pressure-sensitive adhesive layer preferably has photocurability.

(1) At least one of the pressure-sensitive adhesive layers is composed of a (meth)acrylic copolymer (A) in which chemical bonds are formed by hydroxyl groups and isocyanate groups or amino groups and isocyanate groups, as described below. It is precured and contains a photoinitiator (C).
(2) At least one adhesive layer has a benzophenone structure, a benzyl structure, an o-benzoylbenzoic acid ester structure, a thioxanthone structure, a 3-ketocoumarin structure, a 2-ethylanthraquinone structure and a camphorquinone structure, as described below. It is precured with a (meth)acrylic copolymer (A) having one or more photocrosslinkable structural sites selected from.
(3) At least one of the pressure-sensitive adhesive layers is formed from a pressure-sensitive adhesive resin composition containing a hydrogen abstraction photoinitiator (c2) and precured with the hydrogen abstraction initiator (c2).

(Formation of pressure-sensitive adhesive layer according to (1) above)
In (1) above, the photoinitiator (C) is preferably contained in an amount of 0.3% by mass or more relative to the total mass of the pressure-sensitive adhesive layer, that is, the total mass of the pressure-sensitive adhesive layer-forming material.
In addition, the content of the photoinitiator (C) is preferably 0.4% by mass or more, particularly 0.6% by mass or more, from the viewpoint of imparting sufficient photocurability to the adhesive sheet. is more preferable, and 0.8% by mass or more is particularly preferable.

In this way, the presence of the photoinitiator (C) in the pressure-sensitive adhesive layer while remaining active allows the present pressure-sensitive adhesive sheet to be photocurable, that is, cured after lamination to an adherend (main curing). ) can be provided with post-curing properties.
In the pressure-sensitive adhesive layer, since any one of two or more continuous layers should be photocurable, at least one of the layers should contain the photoinitiator (C).

Therefore, from this point of view, the content of the photoinitiator (C) is not the content of each layer in the two or more pressure-sensitive adhesive layers, but the light contained in the entire pressure-sensitive adhesive layer formed by laminating a plurality of layers. Content of initiator (C) is shown.

In the above (1), the photoinitiator (C) may be either the cleavage photoinitiator (c1) or the hydrogen abstraction photoinitiator (c2), and both may be used alone. They may be mixed and used, and each of them may be used singly or in combination of two or more.

(Formation of pressure-sensitive adhesive layer according to (2) above)
In the above (2), at least one layer of the pressure-sensitive adhesive layer is precured by irradiating the photocrosslinkable structural site of the (meth)acrylic copolymer (A) with light, and the photocrosslinking Since the functional structure part can be fully cured by light irradiation again, the adhesive sheet is photocurable, that is, it can be cured (mainly cured) after being attached to the adherend. can be endowed with sexuality.

(Formation of pressure-sensitive adhesive layer according to (3) above)
In the above (3), at least one layer of the pressure-sensitive adhesive layer is precured by light irradiation of a pressure-sensitive adhesive resin composition containing a hydrogen abstraction type photoinitiator (c2), and the photoinitiator ( Since c2) can be fully cured by light irradiation again, the present pressure-sensitive adhesive sheet is photocurable, that is, it can be cured (mainly cured) after being attached to an adherend. can be provided.

In addition, in (3) above, the hydrogen abstraction type photoinitiator (c2) is added to the total mass of the adhesive layer, i.e., the total mass of the adhesive layer-forming material, as in the case of (1) above. , preferably 0.3% by mass, preferably 0.4% by mass or more, more preferably 0.6% by mass or more, and particularly preferably 0.8% by mass or more.
In addition, the content of the hydrogen abstraction initiator (c2) is not the content of each layer in the two or more pressure-sensitive adhesive layers, as described above, but the entire pressure-sensitive adhesive layer formed by laminating a plurality of layers. The content of hydrogen abstraction type initiator (c2) contained is shown.

<<This resin composition>>
This resin composition is a resin composition containing at least a (meth)acrylic copolymer (A).
In addition to the (meth)acrylic copolymer (A), the present resin composition optionally contains a crosslinking agent (B), a photoinitiator (C), a rust inhibitor (D), a silane coupling agent ( E), other components such as a tackifying resin (F) may be contained. In particular, it is more preferable to contain a cross-linking agent (B) and a rust inhibitor (D).

In this case, the present resin composition preferably contains the (meth)acrylic copolymer (A) as a main component.
Here, the "main component" means the component with the largest mass ratio in the adhesive resin composition forming each layer. At this time, the content of the main component is 50% by mass or more, preferably 70% by mass or more, and particularly preferably 90% by mass or more (including 100%) of the adhesive resin composition constituting each layer. .

(Adhesive resin composition forming the first adhesive layer)
The pressure-sensitive adhesive resin composition forming the first pressure-sensitive adhesive layer preferably does not contain a cross-linking agent (B) from the viewpoint of securing the adhesive strength, especially the adhesive properties at low temperatures.
Furthermore, the pressure-sensitive adhesive resin composition forming the first pressure-sensitive adhesive layer preferably contains a rust preventive from the viewpoint of ensuring a higher level of metal corrosion resistance.

(Adhesive resin composition forming the second adhesive layer)
From the viewpoint of securing punching workability, the adhesive resin composition forming the second adhesive layer preferably has a higher content of the cross-linking agent (B) than the first adhesive layer.
Furthermore, the pressure-sensitive adhesive resin composition forming the second pressure-sensitive adhesive layer is the same (meth)acrylic resin composition as the first pressure-sensitive adhesive layer, from the viewpoint of ensuring a higher level of reliability when laminated with the first pressure-sensitive adhesive layer. It is preferred to use a system copolymer.

<(Meth)acrylic copolymer (A)>
The (meth)acrylic copolymer (A) is used so that the pressure-sensitive adhesive sheet has a shear storage modulus (G′) at a temperature of 25° C. of 100 to 500 kPa or less while having metal corrosion resistance. , as a copolymerization component constituting the copolymer, substantially free of structural units derived from a carboxyl group-containing (meth)acrylate monomer, and as a monomer component constituting the copolymerization, a homopolymer was formed. selected from the group consisting of a low Tg (meth)acrylate monomer (a1) having an initial glass transition temperature (Tg) of less than −30° C., a hydroxyl group-containing (meth)acrylate monomer, and a nitrogen atom-containing (meth)acrylate monomer; and any one or more polar group-containing (meth)acrylate monomers (a2).

Note that "substantially free of structural units derived from carboxyl group-containing (meth)acrylate monomers" means not only the complete absence of structural units derived from carboxyl group-containing (meth)acrylate monomers, but also ( It is meant to include less than 0.5% by mass, preferably less than 0.1% by mass of structural units derived from a carboxyl group-containing (meth)acrylate monomer in the meth)acrylic copolymer.

Further, in the present invention, "(meth)acrylic copolymer" means to include acrylic copolymers and methacrylic copolymers, and "(meth)acrylate" includes acrylates and methacrylates. and "(meth)acryloyl" is meant to include acryloyl and methacryloyl.

Examples of the carboxyl group-containing (meth)acrylate monomer include acrylic acid, methacrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, citraconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid, and the like. can be mentioned.

<Low Tg (meth)acrylate monomer (a1)>
Examples of the low Tg (meth)acrylate monomer (a1) having a glass transition temperature (Tg) of less than −30° C. when forming the homopolymer include 2-ethylhexyl acrylate (Tg; −70° C.), n-butyl Acrylate (Tg; -55°C), n-octyl (meth)acrylate (Tg; -65°C), isooctyl acrylate (Tg; -54°C), nonyl acrylate (Tg; -37°C), isononyl acrylate (Tg ; -58°C) isodecyl acrylate (Tg; -60°C), isodecyl methacrylate (Tg; -41°C), tridecyl acrylate (Tg; -55°C), tridecyl methacrylate (Tg; -40°C), n -lauryl methacrylate (Tg; -65°C), 2-ethoxyethyl methacrylate (Tg; -31°C), ethoxyethoxyethyl acrylate (ethyl carbitol acrylate) (Tg; -67°C), and the like. Among these, from the viewpoint of the glass transition temperature, versatility of the monomer, etc., it is preferable to include at least one selected from the group consisting of 2-ethylhexyl acrylate and n-butyl acrylate as the copolymerization component.

The low Tg (meth) acrylate monomer (a1) preferably contains 30% by mass or more of the total 100% by mass of all monomer components constituting the (meth)acrylic copolymer (A). From the viewpoint of adjusting the glass transition temperature of the polymer, it is more preferably contained in a proportion of 40% by mass or more and 90% by mass or less, and particularly preferably in a proportion of 45% by mass or more and 80% by mass or less.

<Polar group-containing (meth)acrylate monomer (a2)>
Examples of the hydroxyl group-containing (meth)acrylate monomer as the polar group-containing (meth)acrylate monomer (a2) include (meth)acrylate monomers other than the above (a1), such as 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth) acrylate, 5-hydroxypentyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, (4-hydroxymethyl Cyclohexyl)methyl (meth)acrylate and the like can be mentioned.

Further, as the nitrogen atom-containing (meth)acrylate monomer as the polar group-containing (meth)acrylate monomer (a2), aminomethyl (meth)acrylate, aminoethyl (meth)acrylate, t-butylaminoethyl (meth)acrylate , dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, (meth)acryloylmorpholine, N-vinylpyrrolidone, N-vinylcaprolactam, (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N-butyl (Meth)acrylamide, N-hydroxy(meth)acrylamide and the like can be mentioned.

Among them, the hydroxyl group-containing (meth)acrylate monomer includes 2-hydroxyethyl (meth)acrylate, 4- Any one or more selected from the group consisting of hydroxybutyl (meth)acrylate and 6-hydroxyhexyl (meth)acrylate is preferably used.
In addition, as the nitrogen atom-containing (meth)acrylate monomer, N,N-dimethyl (meth)acrylamide, N-butyl, from the viewpoint of imparting polarity to improve the glass transition temperature, versatility of the monomer, and adhesive properties. It is preferable to use one or more selected from the group consisting of (meth)acrylamide and N-hydroxy(meth)acrylamide.

The polar group-containing (meth)acrylate monomer (a2) preferably contains 3% by mass or more in a total of 100% by mass of all monomer components constituting the (meth)acrylic copolymer (A). From the viewpoint of imparting polarity to improve the glass transition temperature and adhesive properties when copolymerized, it is more preferably contained in a proportion of 5% by mass or more and 50% by mass or less, and 8% by mass or more and 30% by mass or less. It is particularly preferred to include them in proportions.

(Other copolymer components)
In the (meth)acrylic copolymer (A), as a copolymer component constituting the copolymer, in addition to the above (a1) and (a2), a linear side chain having 4 to 18 carbon atoms Alternatively, a branched alkyl (meth)acrylate (a3), an epoxy group-containing (meth)acrylate monomer (a4), a (meth)acrylate monomer (a5) having a side chain with 1 to 3 carbon atoms, or the like may be used.

Examples of the linear or branched alkyl (meth)acrylate (a3) having 4 to 18 carbon atoms in the side chain include those other than the above (a1) and (a2), such as isobutyl (meth)acrylate, sec-butyl ( meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, neopentyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, heptyl (meth) acrylate, t- Butylcyclohexyl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, isobornyl (meth)acrylate and the like can be mentioned. These may be used singly or in combination of two or more.
The linear or branched alkyl (meth)acrylate (a3) having 4 to 18 carbon atoms is 3% by mass in a total of 100% by mass of all monomer components constituting the (meth)acrylic copolymer (A). It is preferable to contain more than or more, and in particular, from the viewpoint of adjusting the glass transition temperature when copolymerized, it is more preferable to contain at a ratio of 5% by mass to 50% by mass, and a ratio of 8% by mass to 30% by mass. It is particularly preferred that the

Examples of the epoxy group-containing (meth)acrylate monomer (a4) include those other than the above (a1) and (a2), such as glycidyl (meth)acrylate, methylglycidyl (meth)acrylate, 3,4-epoxycyclohexylmethyl ( meth)acrylate, 4-hydroxybutyl (meth)acrylate glycidyl ether, and the like. These may be used alone or in combination of two or more.
The epoxy group-containing (meth)acrylate monomer (a4) preferably contains 1% by mass or more based on the total 100% by mass of all monomer components constituting the (meth)acrylic copolymer (A). From the viewpoint of imparting cohesive strength and adhesive strength to the adhesive sheet, it is more preferably contained in a proportion of 2% by mass or more and 30% by mass or less, and particularly preferably in a proportion of 3% by mass or more and 15% by mass or less.

The (meth)acrylate monomer (a5) having 1 to 3 carbon atoms in the side chain is other than the above (a1) and (a2), such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (Meth)acrylate, i-propyl (meth)acrylate and the like can be mentioned. These may be used alone or in combination of two or more.
The (meth)acrylate monomer (a5) having 1 to 3 carbon atoms in the side chain is 1% by mass or more in the total 100% by mass of all monomer components constituting the (meth)acrylic copolymer (A). It is preferable to contain it, and in particular, from the viewpoint of adjusting the glass transition temperature when copolymerized, it is more preferable to contain it in a proportion of 3% by mass or more and 50% by mass or less, and in a proportion of 5% by mass or more and 30% by mass or less. It is particularly preferred to include

Among those mentioned above, the (meth)acrylic copolymer (A) includes the above (a3) and/or (a5) in addition to the above (a1) and (a2) as copolymer components constituting the copolymer. ) is a ternary or quaternary copolymer containing any of the above, by adjusting the glass transition temperature and polarity when copolymerized, and maintaining adhesive properties such as cohesion and adhesive strength in a well-balanced manner. It is particularly preferable from the viewpoint of imparting.
In the present invention, even when the glass transition temperature (Tg) of the copolymer components (a2) to (a5) is less than -30°C, these are low Tg (meth)acrylate monomers (a1). Instead, they are handled as (a2) to (a5).

The (meth)acrylic copolymer (A) forms a crosslinked structure between the copolymers, and the shape retention of the photocurable adhesive sheet and the adhesive at a temperature of 25 ° C. From the viewpoint of keeping the shear storage modulus (G′) of the sheet within the above range and from the viewpoint of keeping the measured Tg of the present pressure-sensitive adhesive sheet within the above range, chemical A bond is preferably formed.

More specifically, the (meth)acrylic copolymer (A) contains a hydroxyl group-containing (meth)acrylate as a copolymer component, and further contains an isocyanate compound having an isocyanate group that reacts with the hydroxyl group. Using a resin composition, heating or curing, reacting the side chain hydroxyl group of the (meth)acrylic copolymer (A) with the isocyanate group of the isocyanate compound to form a chemical bond between the functional groups. or the (meth)acrylic copolymer (A) contains an amino group (meth)acrylate as a copolymerization component, and in the same manner as described above, the Using a pressure-sensitive adhesive resin composition containing an isocyanate compound having an isocyanate group that reacts with an amino group, heating or curing, the amino group of the side chain of the (meth)acrylic copolymer (A) and the isocyanate compound can be exemplified by a method of forming the pressure-sensitive adhesive layer by reacting with the isocyanate group of to form a chemical bond.

Examples of the isocyanate compounds include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, hydrogenated tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, hexamethylene diisocyanate, diphenylmethane -4,4-diisocyanate, isophorone diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, tetramethylxylylene diisocyanate, 1,5-naphthalene diisocyanate, triphenylmethane triisocyanate and other isocyanate compounds. .

In addition, the compound having an isocyanate group includes, for example, 2-acryloyloxyethyl isocyanate, 2-methacryloyloxyethyl isocyanate, 1,1-(bisacryloyloxymethyl)ethyl isocyanate, and a (meth)acryloyl group. It may have a radically polymerizable functional group.
Thus, the (meth)acrylic copolymer (A) has a radically polymerizable functional group, so that the crosslinking reaction between the (meth)acrylic copolymer (A) due to the radically polymerizable functional group By utilizing, even without using a carboxyl group-containing (meth)acrylate monomer or a cross-linking agent (B), the cohesive force after photocuring (cross-linking) is likely to efficiently increase, and there are advantages such as excellent reliability, which is more preferable. .

From the same viewpoint as above, the (meth)acrylic copolymer (A) preferably has a photocrosslinkable structural site. The photocrosslinkable structural site refers to a structural site that can generate radicals by being excited by irradiation with an active energy ray and causing a hydrogen abstraction reaction.
More specifically, the photocrosslinkable structural site is any selected from a benzophenone structure, a benzyl structure, an o-benzoylbenzoic acid ester structure, a thioxanthone structure, a 3-ketocoumarin structure, a 2-ethylanthraquinone structure and a camphorquinone structure. or one or more structures.
When the (meth)acrylic copolymer (A) has such a photocrosslinkable structural site, the (meth)acrylic copolymer (A) is efficiently cured by the photocrosslinkable structural site. It can be (crosslinked), and there is an advantage that the cohesive force after photocuring (crosslinking) can be efficiently increased easily even without using a carboxyl group-containing (meth)acrylate monomer or a crosslinking agent (B), and the reliability is excellent.

In order for the (meth)acrylic copolymer (A) to have the above photocrosslinkable structural site, the copolymer component may be, for example, 4-acryloyloxybenzophenone, 4-acryloyloxyethoxybenzophenone, 4-acryloyloxy-4 '-Methoxybenzophenone, 4-acryloyloxyethoxy-4'-methoxybenzophenone, 4-acryloyloxy-4'-bromobenzophenone, 4-acryloyloxyethoxy-4'-bromobenzophenone, 4-methacryloyloxybenzophenone, 4-methacryloyloxy ethoxybenzophenone, 4-methacryloyloxy-4'-methoxybenzophenone, 4-methacryloyloxyethoxy-4'-methoxybenzophenone, 4-methacryloyloxy-4'-bromobenzophenone, 4-methacryloyloxyethoxy-4'-bromobenzophenone and these A (meth)acrylate monomer having a benzophenone structure such as a mixture of
By using a (meth)acrylate monomer having such a photocrosslinkable structural site, a photocrosslinkable structural site can be formed in the (meth)acrylic copolymer (A).

<Crosslinking agent (B)>
As the cross-linking agent (B), a cross-linking agent having at least double bond cross-linking is preferable. At least one crosslinkable functional group selected from, for example, (meth)acryloyl groups, epoxy groups, isocyanate groups, carboxyl groups, hydroxyl groups, carbodiimide groups, oxazoline groups, aziridine groups, vinyl groups, amino groups, imino groups, and amide groups and may be used alone or in combination of two or more.
Among the above, as described above, it is particularly preferable to use an isocyanate compound as the cross-linking agent (B) from the viewpoint of forming a cross-linked structure between the (meth)acrylic copolymers (A).

In addition to the above, it is also preferable to use a photopolymerizable compound having a carbon-carbon double bond, particularly a polyfunctional (meth)acrylate, as the cross-linking agent (B).
Here, polyfunctional refers to having two or more crosslinkable functional groups.
In addition, you may have 3 or more and 4 or more crosslinkable functional groups as needed.

By using a polyfunctional (meth)acrylate as the cross-linking agent (B), the polyfunctional monomers are chemically bonded to each other to form a chemically crosslinked structure consisting of a three-dimensional network structure. By entangling the chain-like (meth)acrylic copolymer with the network structure, the movement of the polymer is restrained, and a physical aggregation structure, ie, a physical crosslinked structure can be formed.

Examples of the polyfunctional (meth)acrylates include 1,4-butanediol di(meth)acrylate, glycerin di(meth)acrylate, neopentyl glycol di(meth)acrylate, glycerin glycidyl ether di(meth)acrylate, 1, 6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, tricyclodecane dimethacrylate, tricyclodecanedimethanol di(meth)acrylate, bisphenol A polyethoxydi(meth)acrylate, bisphenol A poly Propoxy di (meth) acrylate, bisphenol F polyethoxy di (meth) acrylate, ethylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane trioxyethyl (meth) acrylate, ε-caprolactone modified tris(2) - hydroxyethyl)isocyanurate tri(meth)acrylate, pentaerythritol tri(meth)acrylate, propoxylated pentaerythritol tri(meth)acrylate, ethoxylated pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, propoxylated Pentaerythritol tetra(meth)acrylate, ethoxylated pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, polyethylene glycol di(meth)acrylate, tris(acryloxyethyl)isocyanurate, dipentaerythritol hexa(meth)acrylate ) acrylate, dipentaerythritol penta(meth)acrylate, tripentaerythritol hexa(meth)acrylate, tripentaerythritol penta(meth)acrylate, neopentyl glycol hydroxybivalate di(meth)acrylate, neopentyl glycol hydroxybivalate ε-caprolactone adduct di(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolpropane polyethoxytri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, and other ultraviolet curable polyfunctional ( In addition to meth)acrylic monomers, polyfunctional (meth)acrylic such as polyester (meth)acrylate, epoxy (meth)acrylate, urethane (meth)acrylate, polyether (meth)acrylate, etc. Oligomers may be mentioned. These may be used singly or in combination of two or more.

As described above, the present pressure-sensitive adhesive sheet has two or more continuous pressure-sensitive adhesive layers with different shear storage elastic moduli (G′) at a temperature of 25° C. At least two of the pressure-sensitive adhesive layers are In order to have different shear storage elastic moduli (G') at a temperature of 25°C, it is preferred that either layer is formed from a pressure-sensitive adhesive resin composition containing a cross-linking agent (B).
From the same point of view, it is preferable that at least one of the pressure-sensitive adhesive layers is formed from a pressure-sensitive adhesive resin composition that does not contain the cross-linking agent (B).
In particular, from the viewpoint of achieving both cutting workability and punching workability for complicated shapes, and reliability and adhesive strength after bonding to an adherend, in the above-described laminated structure, the second pressure-sensitive adhesive layer It is preferable that the second pressure-sensitive adhesive layer is formed from a pressure-sensitive adhesive resin composition having a higher content of the cross-linking agent (B) than the first pressure-sensitive adhesive layer. It is preferable that the first pressure-sensitive adhesive layer is formed from a resin composition and formed from a pressure-sensitive adhesive resin composition that does not contain the cross-linking agent (B). Thus, by adjusting the degree of cross-linking between the first adhesive layer and the second adhesive layer that constitute the adhesive sheet, one layer has a low Tg as a measured value, and the other layer has a temperature of 25 It is possible to design a high shear storage modulus (G') at °C.
However, as described above, the degree of cross-linking of each layer can be adjusted by the cross-linking structure between (meth)acrylic copolymers, so the cross-linking agent (B) is not necessarily essential.

The amount of the cross-linking agent (B) added to the second pressure-sensitive adhesive layer is preferably 5 parts by weight or more, and 10 parts by weight or more and 100 parts by weight with respect to 100 parts by weight of the (meth)acrylic copolymer. It is more preferably 15 parts by weight or less and 50 parts by weight or less.
The molecular weight of the cross-linking agent (B) is preferably 1000 or less, more preferably 50 or more and 800 or less, and even more preferably 100 or more and 600 or less.
The molecular weight per reactive functional group of the cross-linking agent (B) is preferably 300 or less, more preferably 30 or more and 250 or less, and even more preferably 60 or more and 150 or less.
It is preferable that the Tg of the crosslinked product of the single crosslinking agent is 100° C. or higher, preferably 200° C. or higher.
The elastic modulus of the pressure-sensitive adhesive layer or pressure-sensitive adhesive laminate can be adjusted within a predetermined range by adjusting the amount of the cross-linking agent added, the molecular weight of the cross-linking agent, the molecular weight per reactive functional group of the cross-linking agent, and the Tg of the cross-linking agent within the above ranges. Since it becomes easier, it becomes easier to impart punching workability.

<Photoinitiator (C)>
Preferred examples of the photoinitiator (C) include compounds that generate active radical species upon irradiation with light such as ultraviolet light and visible light, more specifically, light with a wavelength of 200 nm to 780 nm. can.

As the photoinitiator (C), as described above, either the cleavage photoinitiator (c1) or the hydrogen abstraction photoinitiator (c2) may be used. may be used as a mixture, and each may be used alone or in combination of two or more.

Examples of the cleavage photoinitiator (c1) include 2,2-dimethoxy-1,2-diphenylethan-1-one, 1-hydroxycyclohexylphenylketone, 2-hydroxy-2-methyl-1-phenyl-propane- 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), phenylgly Methyl oxylic acid, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butan-1-one, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropane- 1-one, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone, bis(2,4,6-trimethylbenzoyl) )-phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, (2,4,6-trimethylbenzoyl)ethoxyphenylphosphine oxide, bis(2,6-dimethoxybenzoyl)2,4,4- Examples include trimethylpentylphosphine oxide and derivatives thereof.

Examples of the hydrogen abstraction type photoinitiator (c2) include benzophenone, 4-methyl-benzophenone, 2,4,6-trimethylbenzophenone, 4-phenylbenzophenone, 3,3′-dimethyl-4-methoxybenzophenone, 4-( meth)acryloyloxybenzophenone, methyl 2-benzoylbenzoate, methyl benzoylformate, bis(2-phenyl-2-oxoacetic acid)oxybisethylene, 4-(1,3-acryloyl-1,4,7,10,13 -pentoxotridecyl)benzophenone, thioxanthone, 2-chlorothioxanthone, 3-methylthioxanthone, 2,4-dimethylthioxanthone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 2-aminoanthraquinone and its Derivatives etc. can be mentioned.

(Rust inhibitor (D))
The rust inhibitor (D) has an absorption coefficient at 365 nm of 20 mL/g cm or less, especially 10 mL/g cm or less, from the viewpoint of not inhibiting the photocurability of the present resin composition due to the rust inhibitor contained therein. Among them, 5 mL/g·cm or less, particularly preferably 1 mL/g·cm or less.
As the rust preventive agent (D) having such properties, a rust preventive agent having no skeleton selected from a naphthalene skeleton, anthracene skeleton, a thiazole skeleton and a thiadiazole skeleton is preferred. By not having such a skeleton, the rust preventive agent (D) can have an absorption coefficient within the above range.

Also, the rust inhibitor (D) is preferably a hydrophilic compound. When the antirust agent (D) is hydrophilic, the antirust agent ( Since D) is easy to move, for example, it can chemically bond with silver atoms to form a protective film, suppressing the attack (reaction) of radicals generated from the photoinitiator on the metal member, especially silver, by light irradiation. can do.
From this point of view, the water solubility of the metal corrosion inhibitor at 25° C. is preferably 20 g/L or more, particularly 50 g/L or more, and more preferably 100 g/L or more.

Among the antirust agents (D) having an absorption coefficient at 365 nm of 20 mL/g·cm or less and made of hydrophilic compounds, triazole compounds are preferred.
Among them, one or a mixture of two or more selected from benzotriazole, 1,2,3-triazole and 1,2,4-triazole is particularly preferred.
The benzotriazole may be either substituted or unsubstituted benzotriazole, such as 1,2,3-benzotriazole, alkylbenzotriazole such as methyl-1H-benzotriazole, carboxybenzotriazole, 1 -halogenobenzotriazoles such as hydroxybenzotriazole, 5-aminobenzotriazole, 5-phenylthiolbenzotriazole, 5-methoxybenzotriazole, nitrobenzotriazole, chlorobenzotriazole, bromobenzotriazole, fluorobenzotriazole, copper benzotriazole, silver Examples include benzotriazole, benzotriazole silane compounds, and the like.
Among these, 1,2,3-benzotriazole, 1-[N,N-bis(2-ethylhexyl)aminomethyl, and 1-[N,N-bis(2-ethylhexyl)aminomethyl ]benzotriazole, 1-[N,N-bis(2-ethylhexyl)aminomethyl]methylbenzotriazole, 2,2′-[[(methyl-1H-benzotriazol-1-yl)methyl]imino]bisethanol Any one or a mixture of two or more selected from the group consisting of is preferable.

Furthermore, 1,2,4-triazole is solid with a melting point of about 120°C, while 1,2,3-triazole has a melting point of about 20°C and is almost liquid at room temperature. Therefore, 1,2,3-triazole has excellent dispersibility when mixed in the adhesive resin composition, can be uniformly mixed, and has excellent advantages such as easy masterbatch.

The rust preventive agent (D) may be contained in any one of two or more continuous layers of the pressure-sensitive adhesive layer, and the content thereof is 0.00% with respect to the total mass of the pressure-sensitive adhesive layer. 01 to 2% by mass is preferable, and 0.05 to 1% by mass is more preferable.

(Silane coupling agent (E))
As the silane coupling agent (E), from the viewpoint of improving the adhesiveness, especially the adhesiveness to glass materials, for example, unsaturated groups such as vinyl groups, acryloxy groups, and methacryloxy groups, amino groups, epoxy groups, etc. , compounds having hydrolyzable functional groups such as alkoxy groups.
Specific examples of silane coupling agents include N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane. Examples include silane, γ-glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, and the like. Among them, γ-glycidoxypropyltrimethoxysilane or γ-methacryloxypropyltrimethoxysilane can be preferably used from the viewpoints of good adhesion and little discoloration such as yellowing.
The silane coupling agent (E) may be used alone or in combination of two or more.

The silane coupling agent (E) may be contained in any one of two or more continuous layers of the pressure-sensitive adhesive layer, and the content thereof is 0 with respect to the total mass of the pressure-sensitive adhesive layer. 0.01 to 2% by mass, and more preferably 0.05 to 1% by mass.

(Tackifying resin (F))
Examples of the tackifying resin (F) include rosin-based tackifying resins, terpene-based tackifying resins, petroleum-based tackifying resins, styrene-based tackifying resins, epoxy-based tackifying resins, polyamide-based tackifying resins, and elastomer-based tackifying resins. Examples include tackifying resins, phenol-based tackifying resins, ketone-based tackifying resins, and the like. Among these, rosin-based tackifying resins are particularly preferable, and the rosin-based tackifying resins include rosin ester resins such as rosin ester resins, disproportionated rosin ester resins, hydrogenated rosin ester resins, and polymerized rosin ester resins. is preferred.
The tackifying resin (F) can be used alone or in combination of two or more.

The tackifying resin (F) may be contained in any one of two or more consecutive layers of the pressure-sensitive adhesive layer, and the content thereof is 1 to 1 with respect to the total mass of the pressure-sensitive adhesive layer. It is preferably 40% by mass, more preferably 3 to 20% by mass.

(other ingredients)
The present resin composition contains various additives such as antioxidants, light stabilizers, metal deactivators, anti-aging agents, moisture absorbers, polymerization inhibitors, ultraviolet absorbers, and inorganic particles as components other than the above. can be contained as appropriate.

<Physical properties of this adhesive sheet>
This pressure-sensitive adhesive sheet has a loss tangent (Tan δ) at a temperature of 70° C. of 0.45 to 0.75 from the viewpoint of combining the workability and storage stability of the pressure-sensitive adhesive sheet with the adhesive strength and step absorbability during lamination. is preferably 0.48 or more or 0.70 or less, more preferably 0.50 or more or 0.60 or less.
In order to prepare in this way, the degree of curing of the adhesive layer can be adjusted by adjusting the number of parts of the cross-linking agent or initiator in each adhesive layer, or by increasing or decreasing the amount of light during pre-curing. and the thickness (ratio) of the second adhesive layer may be adjusted. However, it is not limited to these methods.

<Manufacturing method of this adhesive sheet>
An example of a method for producing the pressure-sensitive adhesive sheet will be described.
First, the present resin compositions for forming the first pressure-sensitive adhesive layer, the second pressure-sensitive adhesive layer, etc. are prepared.
Specifically, a (meth)acrylic copolymer (A), optionally a cross-linking agent (B), a photoinitiator (C), a rust inhibitor (D) and a silane coupling agent (E), and further Predetermined amounts of other materials and the like are mixed to prepare the present resin composition for forming each layer.

The mixing method at this time is not particularly limited, and the mixing order of each component is not particularly limited.
Further, a heat treatment step may be added during the production of the present resin composition, and in this case, it is desirable to mix the components of the composition in advance and then perform the heat treatment.
Also, a masterbatch obtained by concentrating various mixed components may be used.
The device for mixing is not particularly limited, and for example, a universal kneader, a planetary mixer, a Banbury mixer, a kneader, a gate mixer, a pressure kneader, three rolls or two rolls can be used. You may mix using a solvent as needed.

The present resin composition can be used as a solventless system containing no solvent. When used as a solvent-free system, no solvent remains and the advantage of improved heat resistance and light resistance can be obtained.

The pressure-sensitive adhesive sheet is prepared by applying (coating) the resin composition prepared as described above onto a release sheet to form a first pressure-sensitive adhesive layer, and forming a second pressure-sensitive adhesive layer on the first pressure-sensitive adhesive layer. A method of applying (coating) the present resin composition for formation to form a second adhesive layer, and further forming a first adhesive layer on the formed second adhesive layer, or a method of forming a first adhesive layer in the same manner as described above. A first pressure-sensitive adhesive layer and a second pressure-sensitive adhesive layer are formed, and then the respective coated (coated) surfaces are laminated together. The pressure-sensitive adhesive sheet can be produced by a method of simultaneously forming the second pressure-sensitive adhesive layer.

<Photocurable adhesive sheet with release sheet>
A photocurable pressure-sensitive adhesive sheet with a release sheet according to an embodiment of the present invention has a release sheet on at least one side of the pressure-sensitive adhesive sheet.

As the material for the release sheet, a known film can be appropriately used. For example, polyester film, polyolefin film, polycarbonate film, polystyrene film, acrylic film, triacetyl cellulose film, fluororesin film, etc., coated with silicone resin for release treatment, release paper, etc. can be selected as appropriate. can be used.

When the release sheets are laminated on both sides of the pressure-sensitive adhesive sheet, one release sheet may have the same lamination structure and material as the other release sheet, or may have a different lamination structure and material.
Also, they may have the same thickness or different thicknesses.
In addition, release films with different release forces or different thicknesses can be laminated on both sides of the pressure-sensitive adhesive sheet.

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

The pressure-sensitive adhesive sheet may be produced by directly extruding the resin composition or by injecting the resin composition into a mold without using a release sheet as described above.
Further, the present pressure-sensitive adhesive sheet can be obtained by directly filling the present resin composition between the constituent members for an image display device, which are adherends.

<<Optical film with photocurable adhesive sheet>>
An optical film with a photocurable pressure-sensitive adhesive sheet according to an example of the embodiment of the present invention has a release sheet, the present pressure-sensitive adhesive sheet, and an optical film in this order.

Examples of the optical film include any one selected from the group consisting of a polarizing film, a retardation film, a retardation film, an optical compensation film, and a brightness enhancement film.

<<This laminate>>
A layered product for constituting an image display device according to an example of the embodiment of the present invention (hereinafter referred to as "this layered product") has a structure in which the pressure-sensitive adhesive sheet is laminated via two members for forming an image display device. It is.

In the present laminate, the two constituent members for an image display device are any one selected from the group consisting of a polarizing plate, a liquid crystal display panel, an organic EL (electroluminescence) panel, a plasma display panel, a touch panel, a protective panel, and the like. member can be mentioned.

Specific examples of the present laminate include, for example, a release sheet/this adhesive sheet/various image display panels such as touch panels, liquid crystal display panels, organic EL panels, and plasma display panels (hereinafter collectively referred to as "image display panels")/ Composition of this adhesive sheet/touch panel, image display panel/this adhesive sheet/touch panel/this adhesive sheet/protective panel, polarizing plate/this adhesive sheet/touch panel, polarizing plate/this adhesive sheet/touch panel/this adhesive sheet/protective panel, etc. can be mentioned.

The touch panel includes a structure in which a protective panel has a touch panel function, and a structure in which an image display panel has a touch panel function.
Therefore, the laminate may have a structure such as release sheet/adhesive sheet/protective panel, release sheet/adhesive sheet/image display panel, or image display panel/adhesive sheet/protective panel.
Moreover, in the above-described configurations, all configurations in which the above-described conductive layer is interposed between the present pressure-sensitive adhesive sheet and members such as a touch panel, a protection panel, an image display panel, and a polarizing plate adjacent thereto can be mentioned. However, it is not limited to these lamination examples.

Examples of the touch panel include a resistive film type, a capacitive type, an electromagnetic induction type, and the like. Among them, the capacitive method is preferable.

Materials for the protective panel include glass, acrylic resin, polycarbonate resin, alicyclic polyolefin resin such as cycloolefin polymer, styrene resin, polyvinyl chloride resin, phenol resin, melamine resin, Plastic such as epoxy resin may be used.

<Manufacturing method of the laminate>
The laminate can be produced, for example, by laminating the adhesive sheet and any member selected from the group consisting of a polarizing plate, a liquid crystal display panel, an organic EL display panel, a plasma display panel, a touch panel, and a protective panel. can.
More specifically, after bonding the pressure-sensitive adhesive sheet and the member, the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet is fully cured by irradiating light from the outside of the member through the member. By laminating two members together, the present laminate can be produced.

In the production of the laminate, main curing of the pressure-sensitive adhesive sheet so that the shear storage modulus (G′) of the pressure-sensitive adhesive sheet at a temperature of 25° C. is in the range of more than 500 kPa and less than 1,000 kPa, It is particularly preferable from the viewpoint of enhancing the reliability after the main curing and suppressing the transfer of unevenness to the pressure-sensitive adhesive sheet. That is, the present pressure-sensitive adhesive sheet after lamination, that is, the present pressure-sensitive adhesive sheet after light irradiation and main curing has a shear storage modulus (G′) at a temperature of 25° C. of more than 500 kPa and less than 1,000 kPa. preferable.
In addition, the present pressure-sensitive adhesive sheet after lamination, that is, after laminating the present pressure-sensitive adhesive sheet and the above-mentioned member, and irradiating light (after main curing), the pressure-sensitive adhesive sheet has a loss tangent of the pressure-sensitive adhesive sheet at a temperature of 70 ° C. (Tg) of 0.15 or more and less than 0.45 is particularly preferable from the viewpoint of enhancing reliability after main curing and suppressing deformation when compressed in the thickness direction.

In order for the present pressure-sensitive adhesive sheet to have such permanent curability, it preferably has a pressure-sensitive adhesive layer formed from the present resin composition. Using a (meth)acrylic copolymer (A) in which a bond is formed, a benzophenone structure, a benzyl structure, an o-benzoylbenzoic acid ester structure, a thioxanthone structure, a 3-ketocoumarin structure, a 2-ethylanthraquinone structure and A (meth)acrylic copolymer having at least one photocrosslinkable structural site selected from camphorquinone structures is used, or a pressure-sensitive adhesive resin composition containing a crosslinking agent (B) is used. It is preferable to have a pressure-sensitive adhesive layer formed by

The method of bonding two members together via the adhesive sheet is not particularly limited, and one member may be bonded to the adhesive sheet and then bonded to the other member. The two members may be bonded together with the pressure-sensitive adhesive sheet.

<<this image display device>>
An image display device according to an example of an embodiment of the present invention (hereinafter referred to as "the present image display device") has the present laminate.
Specific examples of the present image display device include a liquid crystal display, an organic EL (electroluminescence) display, an inorganic EL display, an electronic paper, a plasma display, and a micro-electromechanical system (MEMS) display having the laminate. .

<<explanation of words>>
In this specification, when expressed as "X to Y" (X and Y are arbitrary numbers), unless otherwise specified, "X or more and Y or less" and "preferably larger than X" or "preferably Y It also includes the meaning of "less than".
In addition, when expressed as "X or more" (X is an arbitrary number) or "Y or less" (Y is an arbitrary number), "preferably larger than X" or "preferably less than Y" It also includes intent.

Examples and comparative examples will be described below in more detail. However, the present invention is not limited to these examples.

[Material evaluation]
<Hydroxyl value>
The hydroxyl value of the copolymer was measured by the neutralization titration method.
A sample was collected in an Erlenmeyer flask, 10 ml of a mixed solution of acetic anhydride:pyridine=1:13 was added with a whole pipette, and further 10 ml of toluene was added.
An air-cooling tube was attached to the top of the Erlenmeyer flask and heated at 95° C. for 90 minutes.
After heating, 10 ml of toluene and 10 ml of pure water were added, and the mixture was allowed to cool while stirring to room temperature.
Then, several drops of phenolphthalein solution were added, and titration was performed with a 0.1 mol/L potassium hydroxide solution.
As a blank test, the same operation as above was carried out without collecting a sample in an Erlenmeyer flask.
The hydroxyl value was calculated based on the following formula.
Calculation formula Hydroxyl value = 5.611 × (Amount of potassium hydroxide solution used for blank test (ml) - Amount of potassium hydroxide solution used for titration (ml)) × F / Amount of collected sample (g) + acid value

<Mass average molecular weight>
The mass average molecular weight of the copolymer was measured using a Gel Permeation Chromatography (GPC) analyzer (device name: HLC-8320GPC manufactured by Tosoh Corporation). Specifically, a measurement sample was prepared by dissolving 4 mg of the copolymer using 12 mL of THF, and the molecular weight distribution curve was measured under the following conditions to determine the weight average molecular weight (Mw).
・Guard column: TSKguard column HXL
・ Separation column: TSKgelGMHXL (4 columns)
・Temperature: 40℃
・Injection volume: 100 μL
・Polystyrene equivalent ・Solvent: THF
・Flow rate: 1.0 mL/min

<Glass transition temperature>
The glass transition temperature (Tg) of the copolymer was measured using a rheometer (manufactured by TA Instruments, "Discovery HR2"). Specifically, adhesive jig: Φ8 mm parallel plate, strain: 0.1%, frequency: 1 Hz, temperature: -50 to 80 ° C., heating rate: 5 ° C./min, -50 ° C. to 80 ° C. Tg was obtained by reading the temperature at which the loss tangent (Tan δ) becomes the maximum value from the obtained data.

<Example 1>
(Meth)acrylic acid ester (co)polymer (A), a copolymer (A-1, weight average molecular weight 44 Ten thousand, Tg -23 ° C., hydroxyl value 67.4 mg KOH / g) 1 kg, 12 g of a mixture of 2,4,6-trimethylbenzophenone and 4-methylbenzophenone (C-1) as an initiator (C), and rust prevention As the agent (D), 2 g of 1,2,3-triazole (D-1) was uniformly melt-kneaded to prepare a pressure-sensitive adhesive resin composition 1.
1,2,3-triazole (D-1) as a metal corrosion inhibitor has an absorption coefficient of 0.3 mL/(g cm) at 365 nm and a water solubility of 1000 g/L at 25°C. it was high.

(A-1) as a (meth)acrylate (co)polymer (A), 1 kg of (A-1) as a cross-linking agent (B), 220 g of pentaerythritol triacrylate (B-1) as an initiator (C), (C-1) 10 g was uniformly melted and kneaded to prepare an adhesive resin composition 2.

The adhesive resin composition 1 was applied to two peel-treated polyethylene terephthalate films (“Diafoil MRF” manufactured by Mitsubishi Chemical Corporation, thickness 75 μm / “Diafoil MRT” manufactured by Mitsubishi Chemical Corporation, thickness 38 μm), that is, 2 It was sandwiched between two release sheets and formed into a sheet at a temperature of 80° C. so as to have a thickness of 25 μm, to prepare a surface pressure-sensitive adhesive sheet (1-1).
Two polyethylene terephthalate films (“Diafoil MRF” manufactured by Mitsubishi Chemical Corporation, thickness 75 μm / “Diafoil MRT” manufactured by Mitsubishi Chemical Corporation, thickness 38 μm) obtained by peeling the adhesive resin composition 2, that is, two sheets and formed into a sheet at a temperature of 80° C. so as to have a thickness of 100 μm, to prepare a middle layer pressure-sensitive adhesive sheet (2-1).

The PET films on both sides of the intermediate layer sheet (2-1) are sequentially peeled and removed, and the adhesive surface of the surface layer sheet (1-1) is sequentially laminated to both surfaces, and the adhesive sheet (1-1) / ( A laminate consisting of 2-1)/(1-1) was produced.
Through the PET film remaining on the surface of the surface layer sheet (1-1), light is irradiated from a high-pressure mercury lamp so that the integrated amount of light at a wavelength of 365 nm is 1000 mJ/cm ² , precured, and transparent both surfaces are cured. An adhesive sheet laminate 1 was produced.
In the transparent double-sided pressure-sensitive adhesive sheet laminate 1, the shear storage modulus (G′) of the surface layer at a temperature of 25° C. is lower than that of the middle layer, leaving room for photocuring of any layer by light irradiation. (precured product).

<Example 2>
(A-1) as a (meth)acrylate (co)polymer (A), 1 kg of (A-1) as a cross-linking agent (B), 250 g of pentaerythritol triacrylate (B-1) as an initiator (C), (C-1) 10 g was uniformly melted and kneaded to prepare an adhesive resin composition 3.

The adhesive resin composition 1 was applied to two peel-treated polyethylene terephthalate films (“Diafoil MRF” manufactured by Mitsubishi Chemical Corporation, thickness 75 μm / “Diafoil MRT” manufactured by Mitsubishi Chemical Corporation, thickness 38 μm), that is, 2 It was sandwiched between two release sheets and formed into a sheet at a temperature of 80° C. so as to have a thickness of 25 μm, to prepare a pressure-sensitive adhesive sheet for surface layer (1-2).

Two polyethylene terephthalate films (“Diafoil MRF” manufactured by Mitsubishi Chemical Corporation, thickness 75 μm / “Diafoil MRT” manufactured by Mitsubishi Chemical Corporation, thickness 38 μm) obtained by peeling the adhesive resin composition 3, that is, two sheets and formed into a sheet at a temperature of 80° C. so as to have a thickness of 100 μm, to prepare a middle layer pressure-sensitive adhesive sheet (3-2).

The PET films on both sides of the intermediate layer sheet (3-2) are sequentially peeled and removed, and the adhesive surface of the surface layer sheet (1-2) is sequentially laminated to both surfaces, and the adhesive sheet (1-2) / ( A laminate consisting of 3-2)/(1-2) was produced.
Through the PET film remaining on the surface of 1-2, light is irradiated from a high-pressure mercury lamp so that the integrated amount of light at a wavelength of 365 nm is 1000 mJ/cm ² , precured, and transparent double-sided adhesive sheet laminate 2 was made.
In the transparent double-sided pressure-sensitive adhesive sheet laminate 2, the shear storage modulus (G') of the surface layer at a temperature of 25°C is lower than that of the middle layer, and there is room for photocuring of any layer by light irradiation. (precured product).

<Example 3>
(Meth)acrylic acid ester (co)polymer (A), (A-1) 1 kg, (B-1) 180 g as crosslinking agent (B), and initiator (C), (C-1 ) was uniformly melted and kneaded to prepare an adhesive resin composition 4.

The pressure-sensitive adhesive resin composition 1 was applied to two polyethylene terephthalate films (“Diafoil MRF” manufactured by Mitsubishi Chemical Co., Ltd., thickness 75 μm / “Diafoil MRT” manufactured by Mitsubishi Chemical Co., thickness 38 μm), that is, sandwiched between two release sheets and formed into a sheet at a temperature of 80° C. so as to have a thickness of 25 μm, to prepare a pressure-sensitive adhesive sheet for surface layer (1-3).
Two polyethylene terephthalate films (“Diafoil MRF” manufactured by Mitsubishi Chemical Corporation, thickness 75 μm / “Diafoil MRT” manufactured by Mitsubishi Chemical Corporation, thickness 38 μm) obtained by peeling the adhesive resin composition 4, that is, two sheets and formed into a sheet at a temperature of 80° C. to a thickness of 100 μm to prepare an adhesive sheet for middle layer (4-3).

The PET films on both sides of the intermediate layer sheet (4-3) are sequentially peeled off, and the adhesive surface of the surface layer sheet (1-3) is sequentially laminated to both surfaces, and the adhesive sheet (1-3) / ( A laminate consisting of 4-3)/(1-3) was produced.
Through the PET film remaining on the surface of the surface layer sheet (1-3), light is irradiated from a high-pressure mercury lamp so that the integrated amount of light at a wavelength of 365 nm is 1000 mJ/cm ² , precured, and transparent both surfaces are cured. An adhesive sheet laminate 3 was produced.
In the transparent double-sided pressure-sensitive adhesive sheet laminate 3, the shear storage modulus (G′) of the surface layer at a temperature of 25° C. is lower than that of the middle layer, leaving room for photocuring of any layer by light irradiation. (precured product).

<Example 4>
(Meth)acrylic acid ester (co)polymer (A), (A-1) 1 kg, initiator (C), (C-1) 12 g, rust inhibitor (D), 1,2 , and 2 g of 4-triazole (D-2) were uniformly melt-kneaded to prepare an adhesive resin composition 5.
1,2,4-triazole (D-2) as a metal corrosion inhibitor has an absorption coefficient at 365 nm of 0.3 mL/(g cm) and a water solubility at 25° C. of 1000 g/L. it was high.

The pressure-sensitive adhesive resin composition 5 was applied to two peel-treated polyethylene terephthalate films ("Diafoil MRF" manufactured by Mitsubishi Chemical Corporation, thickness 75 μm/"Diafoil MRT" manufactured by Mitsubishi Chemical Corporation, thickness 38 μm). It was sandwiched between two release sheets and formed into a sheet at a temperature of 80° C. so as to have a thickness of 15 μm to prepare a surface pressure-sensitive adhesive sheet (5-4).
The adhesive resin composition 2 is sandwiched between two peel-treated polyethylene terephthalate films (“Diafoil MRF” manufactured by Mitsubishi Chemical Corporation, thickness 75 μm / “Diafoil MRT” manufactured by Mitsubishi Chemical Corporation, thickness 38 μm), It was formed into a sheet at a temperature of 80° C. so as to have a thickness of 120 μm, to prepare an adhesive sheet for middle layer (2-4).

The PET films on both sides of the adhesive sheet for intermediate layer (2-4) are sequentially peeled off, and the adhesive surface of the adhesive sheet for surface layer (5-4) is sequentially laminated on both surfaces to form an adhesive sheet (5-4). A laminate consisting of /(2-4)/(5-4) was produced.
Through the PET film remaining on the surface of the adhesive sheet for surface layer (5-4), light is irradiated from a high-pressure mercury lamp so that the integrated amount of light at a wavelength of 365 nm is 1000 mJ/cm ² , precured, and transparent. A double-sided pressure-sensitive adhesive sheet laminate 4 was produced.
In the transparent double-sided pressure-sensitive adhesive sheet laminate 4, the shear storage modulus (G′) of the surface layer at a temperature of 25° C. is lower than that of the middle layer, leaving room for photocuring of any layer by light irradiation. (precured product).

<Example 5>
(Meth) acrylic acid ester (co) polymer (A), (A-1) 1 kg, as a cross-linking agent (B), (B-2) 1 g, and as an initiator (C), (C-1 ) were uniformly melted and kneaded to prepare an adhesive resin composition 6.

The adhesive resin composition 6 was applied to two peel-treated polyethylene terephthalate films (“Diafoil MRF” manufactured by Mitsubishi Chemical Corporation, thickness 75 μm / “Diafoil MRT” manufactured by Mitsubishi Chemical Corporation, thickness 38 μm). It was sandwiched between two release sheets and formed into a sheet at a temperature of 80° C. to a thickness of 35 μm to prepare a surface pressure-sensitive adhesive sheet 6-5.
Two polyethylene terephthalate films (“Diafoil MRF” manufactured by Mitsubishi Chemical Corporation, thickness 75 μm / “Diafoil MRT” manufactured by Mitsubishi Chemical Corporation, thickness 38 μm) obtained by peeling the adhesive resin composition 2, that is, two sheets and formed into a sheet at a temperature of 80° C. to a thickness of 80 μm to prepare an adhesive sheet for middle layer (2-5).

The PET films on both sides of the adhesive sheet for intermediate layer (2-5) are sequentially peeled off, and the adhesive surface of the adhesive sheet for surface layer (6-5) is sequentially laminated on both surfaces to form an adhesive sheet (6-5). A laminate consisting of /(2-5)/(6-5) was produced.
Through the PET film remaining on the surface of the pressure-sensitive adhesive sheet for surface layer (6-5), light is irradiated from a high-pressure mercury lamp so that the integrated amount of light at a wavelength of 365 nm becomes 1000 mJ/cm ² , pre-cured, and transparent both surfaces. An adhesive sheet laminate 5 was produced.
In the transparent double-sided pressure-sensitive adhesive sheet laminate 5, the shear storage modulus (G′) of the surface layer at a temperature of 25° C. is lower than that of the middle layer, leaving room for photocuring of any layer by light irradiation. (precured product).

<Comparative Example 1>
(Meth)acrylic acid ester (co)polymer (A), 2-ethylhexyl acrylate (Tg; -70 ° C.) / 2-hydroxy acrylate / methyl acrylate copolymer (A-2, mass average molecular weight 280,000 , Tg 2 ° C., hydroxyl value 68.6 mg KOH / g) 1 kg, (B-2) 15 g as a cross-linking agent (B), (C-1) 18 g as an initiator (C), and a rust inhibitor (D) 2 g of (D-1) were uniformly melt-kneaded to prepare an adhesive resin composition 7.

The pressure-sensitive adhesive resin composition 7 is sandwiched between two release-treated polyethylene terephthalate films (“Diafoil MRF” thickness 75 μm/“Diafoil MRT” thickness 38 μm), that is, two release sheets. Form into a sheet at a temperature of 80 ° C. so that the thickness is 150 μm, and irradiate light from one side of the polyethylene terephthalate film with a high-pressure mercury lamp so that the integrated light amount at a wavelength of 365 nm becomes 3000 mJ / cm ² , and prepare. By curing, a transparent double-sided pressure-sensitive adhesive sheet 6 was produced.
In addition, the adhesive layer in the transparent double-sided adhesive sheet 6 left room for photocuring by light irradiation (precured product).

<Comparative Example 2>
The pressure-sensitive adhesive resin composition 1 was sandwiched between two release-treated polyethylene terephthalate films (“Diafoil MRF” thickness 75 μm/“Diafoil MRT” thickness 38 μm), that is, two release sheets, and the thickness was 150 μm. Then, from one polyethylene terephthalate film side, light is irradiated from a high-pressure mercury lamp so that the integrated light amount at a wavelength of 365 nm is 1000 mJ/cm ² , and pre-cured. Thus, a transparent double-sided adhesive sheet 7 was produced.
In addition, the adhesive layer in the transparent double-sided adhesive sheet 7 had room for photocuring by light irradiation (precured product).

<Comparative Example 3>
The pressure-sensitive adhesive resin composition 2 was sandwiched between two release-treated polyethylene terephthalate films (“Diafoil MRF” thickness 75 μm / “Diafoil MRT” thickness 38 μm), that is, two release sheets, and the thickness was 150 μm. Formed into a sheet at a temperature of 80 ° C., and pre-cured by irradiating light from one polyethylene terephthalate film side with a high-pressure mercury lamp so that the integrated light amount at a wavelength of 365 nm is 1000 mJ / cm ² . Then, a transparent double-sided adhesive sheet 8 was produced.
In addition, the adhesive layer in the transparent double-sided adhesive sheet 8 left room for photocuring by light irradiation (precured product).

<Comparative Example 4>
(A-1) as a (meth)acrylic ester (co)polymer (A), 1 kg of (A-1) as a cross-linking agent (B), propoxylated pentaerythritol triacrylate (B-3) 100 g, and an initiator (C ), and 10 g of (C-1) were uniformly melt-kneaded to prepare an adhesive resin composition 8.

Two polyethylene terephthalate films (“Diafoil MRF” manufactured by Mitsubishi Chemical Corporation, thickness 75 μm / “Diafoil MRT” manufactured by Mitsubishi Chemical Corporation, thickness 38 μm) obtained by peeling the adhesive resin composition 5, that is, two sheets and formed into a sheet at a temperature of 80° C. so as to have a thickness of 35 μm, to prepare a surface pressure-sensitive adhesive sheet (5-9).

Two polyethylene terephthalate films (“Diafoil MRF” manufactured by Mitsubishi Chemical Co., Ltd., thickness 75 μm / “Diafoil MRT” manufactured by Mitsubishi Chemical Co., Ltd., thickness 38 μm) as two release sheets obtained by subjecting the adhesive resin composition 8 to a release treatment ), that is, sandwiched between release sheets and formed into a sheet at a temperature of 80° C. so as to have a thickness of 80 μm, to prepare an intermediate layer pressure-sensitive adhesive sheet (8-9).

The PET films on both sides of the adhesive sheet for the intermediate layer (8-9) are sequentially peeled off, and the adhesive surfaces of the adhesive sheet for the surface layer (5-9) are sequentially laminated on both surfaces to form the adhesive sheet (5-9). A laminate consisting of /(8-9)/(5-9) was produced.
Through the PET film remaining on the surface adhesive sheet (5-9), light is irradiated from a high-pressure mercury lamp so that the integrated amount of light at a wavelength of 365 nm is 1800 mJ/cm ² , precured, and transparent. A double-sided pressure-sensitive adhesive sheet laminate 6 was produced.
In the transparent double-sided pressure-sensitive adhesive sheet laminate 6, all layers had room for photocuring by light irradiation (precured product).

[Evaluation of the physical properties]
The physical properties of the transparent double-sided pressure-sensitive adhesive sheet laminate and the transparent double-sided pressure-sensitive adhesive sheet obtained in Examples and Comparative Examples were measured as follows.

<Storage elastic modulus G′ and loss tangent Tan δ>
Pre-cured products prepared in Examples and Comparative Examples, that is, transparent double-sided pressure-sensitive adhesive sheet laminates 1 to 6 and transparent double-sided pressure-sensitive adhesive sheets 6 to 8 before curing (hereinafter collectively referred to as "pre-curing transparent double-sided pressure-sensitive adhesive sheets"). For each of the above, two polyethylene terephthalate films were peeled off, an adhesive layer was laminated to a thickness of 0.6 to 0.8 mm, and a circle with a diameter of 8 mm was punched out to obtain a measurement sample.
Using a rheometer (manufactured by TA Instruments, "Discovery HR2"), adhesive jig: φ8 mm parallel plate, strain: 0.1%, frequency: 1 Hz, temperature: -50 to 200 ° C., heating rate: 5 ° C./min The dynamic viscoelasticity spectrum was measured in the temperature range of -50 ° C to 200 ° C under the conditions of, and from the obtained data, the storage elastic modulus G' of the transparent double-sided pressure-sensitive adhesive sheet before curing at temperatures of 25 ° C and 70 ° C and A loss tangent (Tan δ) was determined.
Further, by reading the temperature at which Tan δ reaches the maximum value, that is, the peak temperature, Tg was obtained as an actually measured value of the pre-cured transparent double-sided pressure-sensitive adhesive sheet.

Next, the pre-curing transparent double-sided pressure-sensitive adhesive sheet is irradiated with light from a high-pressure mercury lamp so that the integrated amount of light at a wavelength of 365 nm is 3000 mJ/cm ² , thereby photocuring the cured transparent double-sided pressure-sensitive adhesive sheet. did.
For each of the cured transparent double-sided pressure-sensitive adhesive sheets (hereinafter collectively referred to as "cured transparent double-sided pressure-sensitive adhesive sheets"), in the same manner as described above, the pressure-sensitive adhesive layer obtained by peeling off two polyethylene terephthalate films was Data obtained by laminating to 0.6 to 0.8 mm and measuring the dynamic viscoelastic spectrum in the temperature range of -50 ° C to 200 ° C under the same measurement conditions as the transparent double-sided adhesive sheet before curing. The storage elastic modulus G′ and loss tangent (Tan δ) of the transparent double-sided pressure-sensitive adhesive sheet after curing at temperatures of 25° C. and 70° C. were determined.
Further, by reading the temperature at which Tan δ reaches the maximum value, that is, the peak temperature, the Tg of the transparent double-sided pressure-sensitive adhesive sheet after curing was obtained as an actual measurement value.

<Tensile modulus (E′)>
The tensile storage modulus (E′) at 25° C. determined by the tensile method was obtained from the precured products prepared in Examples and Comparative Examples, that is, transparent double-sided pressure-sensitive adhesive sheet laminates 1 to 6 and transparent double-sided pressure-sensitive adhesive sheets 6 to 8 before curing. (Hereinafter, collectively referred to as "pre-curing transparent double-sided adhesive sheet".) Each sample was cut into a sample size of 4 mm in width x 15 mm in length, and measured with a dynamic viscoelasticity measuring device (itkDVA-200, manufactured by IT Keisoku Co., Ltd.). ) was used to measure the tensile storage modulus E′ at 25° C. in a tensile mode: vibration frequency of 1 Hz, measurement temperature: from 0° C. to 80° C., and temperature increase rate: 3° C./min.
Next, the pre-curing transparent double-sided pressure-sensitive adhesive sheet is irradiated with light from a high-pressure mercury lamp so that the integrated amount of light at a wavelength of 365 nm is 3000 mJ/cm ² , thereby photocuring the cured transparent double-sided pressure-sensitive adhesive sheet. did. Each of the cured transparent double-sided pressure-sensitive adhesive sheets (hereinafter collectively referred to as "cured transparent double-sided pressure-sensitive adhesive sheet") was cut into a sample size of 4 mm wide x 15 mm long in the same manner as described above. Using a measuring device (itkDVA-200, manufactured by IT Keisoku Control Co., Ltd.), tensile mode: vibration frequency 1 Hz, measurement temperature: 0 ° C to 80 ° C, temperature increase rate: 3 ° C / min, curing at 25 ° C. The post-tensile storage modulus E' was measured.

<Cutability>
Each of the pre-cured transparent double-sided pressure-sensitive adhesive sheets was cut to 50×50 mm using a Thomson punching machine while the release sheet was laminated.
After peeling off the single-sided release sheet, only the adhesive layer was cut to 30 x 30 mm, and the peeled single-sided release sheet was pasted together with a roll, resulting in a double-sided release sheet of 50 x 50 mm and an adhesive layer of 30 x 30 mm. 100 cut products were produced.
Furthermore, the central portion of the cut product of 30×30 mm was punched out together with the release sheet into a circular shape of 2 mmφ.

When the release sheet was peeled off, the glue was stringy or the product was broken up with tears, which was regarded as a defective product. Those in which the number of defective products was suppressed to 1 or less were evaluated as “⊚ (very good)”.

<Punching workability for complex shapes>
A circular shape of 3 mmφ and a square shape of 3×3 mm were punched out together with the release sheet from the central portion of the cut product of 30×30 mm produced in the evaluation of cutting processability, and the state of the punched portions was observed.
Defective products were those in which the adhesive shape at the punched area or its surroundings was dented or crushed, or those in which the adhesive adhered and could not be removed well when removing the scraps after punching, and the number of defective products exceeded 10. Those in which the number of defective products was suppressed to 10 or less were evaluated as “good”.

<Adhesive strength>
One of the release sheets was peeled off from each of the pre-cured transparent double-sided pressure-sensitive adhesive sheets, and a 100 μm PET film (Diafoil T100 manufactured by Mitsubishi Chemical Corporation) was laminated as a backing film.
After cutting this to a length of 150 mm and a width of 10 mm, the remaining release sheet was peeled off, and the exposed adhesive surface was roll-pressed to soda-lime glass to obtain a laminated product.
The laminated product was subjected to an autoclave treatment (60° C., gauge pressure 0.2 MPa, 20 minutes) and then finished to be laminated.
This sample was irradiated from the PET film surface with ultraviolet rays of 365 nm using a high-pressure mercury lamp so that the integrated light amount was 3000 mJ/cm ² , and then cured at a temperature of 23 ° C. and 50% RH for 12 hours to achieve adhesion. A sample for force measurement was produced.
The sample was peeled off at a peel angle of 180° and a peel speed of 60 mm/min in an environment of -20°C or 23°C and 50% RH to measure the peel force (N/cm).
Then, those that can be easily peeled off at less than 1 N/cm are "x (poor)," those that are 1 N/cm or more and 3 N/cm or less are "○ (good)," and those that are 3 N/cm or more are "◎ (very good)." I judged.

<Step absorption>
Each of the transparent double-sided pressure-sensitive adhesive sheets before curing was cut to 50×80 mm using a Thomson punching machine while the release sheet was laminated.
Peel off the release sheet on one side, and apply the exposed adhesive surface to the printed surface of soda lime glass (82 mm × 54 mm × 0.5 mm thick) printed with a thickness of 15 μm or 30 μm on the peripheral edge of 5 mm. It was press-bonded using a vacuum press (temperature: 25° C., press pressure: 0.1 MPa) so that four sides overlap the printing step.
Next, the remaining release sheet was peeled off, and soda-lime glass (82 mm × 54 mm × thickness 0.5 mm) without printing steps was press-bonded, followed by autoclave treatment (60 ° C., gauge pressure 0.2 MPa, 20 minutes). A stepped glass/adhesive sheet/glass laminate was produced by finishing adhesion.

The produced laminate was visually observed.
The pressure-sensitive adhesive sheet did not follow the print level difference and air bubbles remained, making it unsuitable for printing level difference lamination. A case where air bubbles remained was judged to be "good", and a lamination with a good appearance without air bubbles was judged to be "very good".

<Lamination reliability>
The soda lime glass side with printing steps was attached to the sample obtained by bonding the soda lime glass with printing steps of 15 μm, the pre-curing transparent double-sided adhesive sheet, and the soda lime glass without printing steps, which were used for step absorbability evaluation. Then, using a high-pressure mercury lamp, ultraviolet rays of 365 nm were irradiated so that the integrated light amount was 3000 mJ / cm ² , and then cured for 12 hours in an environment at a temperature of 23 ° C. and 50% RH. Three evaluation samples 1 were prepared.
Note that the transparent double-sided pressure-sensitive adhesive sheet 7 among the pre-cured transparent double-sided pressure-sensitive adhesive sheets was not evaluated for bonding reliability because it could not be laminated without air bubbles in the printed steps.

Furthermore, one of the release sheets of the pre-cured transparent double-sided pressure-sensitive adhesive sheets excluding the transparent double-sided pressure-sensitive adhesive sheet 7 was peeled off, and after bonding to a polarizing plate having a thickness of 150 μm, the remaining release sheet was peeled off and the exposed adhesive surface was exposed. A laminated product was obtained by roll pressure bonding to a soda lime glass of 100×150 mm.

The laminated product was subjected to an autoclave treatment (60° C., gauge pressure 0.2 MPa, 20 minutes) and then finished to be laminated. This sample was irradiated from the glass surface with ultraviolet rays of 365 nm using a high-pressure mercury lamp so that the integrated light amount was 3000 mJ/cm ² , and then cured at 23 ° C. and 50% RH for 12 hours. Three evaluation samples 2 were prepared.

Samples 1 and 2 for bonding reliability evaluation were subjected to a thermal shock test using an air tank thermal shock tester (WINTECH NEO NT1050W manufactured by ETAC Co., Ltd.) under the conditions of -40°C in a low temperature chamber and 85°C in a high temperature chamber for 300 cycles. The bonding reliability was evaluated by confirming the appearance after the test.

In any of the six samples for bonding reliability evaluation of the pre-cured transparent double-sided pressure-sensitive adhesive sheet excluding the transparent double-sided pressure-sensitive adhesive sheet 7, foaming occurred at the adherend interface or the adherend peeled off. , "poor" for poor lamination reliability, and "Good" for no change in appearance and excellent lamination reliability for all samples.

<ITO corrosion resistance>
On a 60 x 45 mm glass with a thickness of 0.7 mm, a film of ITO 200 Å was formed under the patterning conditions of line width 70 µm/line spacing 30 µm (patterning accuracy ±8 µm), line length 46 cm, electrode size 5 mm square, and electrode distance 50 mm. A substrate for ITO corrosion resistance evaluation was prepared.
For each of the pre-cured transparent double-sided pressure-sensitive adhesive sheets, the single-sided release film was peeled off, and the sheet was roll-bonded to a PET film (Diafoil T100 manufactured by Mitsubishi Chemical Corporation, thickness 50 μm), and then cut to a width of 52 mm.
After that, the release sheet on the other side was peeled off, and the substrate was laminated with a roll so that the adhesive sheet was positioned between the electrodes. Finished and pasted.
After that, light was irradiated from the PET film side with a high-pressure mercury lamp so that the integrated amount of light at a wavelength of 365 nm was 2000 mJ/cm ² for photocuring (main cured product).
After that, by aging at room temperature for 12 hours, a sample for ITO corrosion resistance evaluation as shown in FIG. 1 was produced.

This sample was subjected to an environmental test under a moist heat environment of 65° C. and 90% RH×500 hours to confirm an increase in the resistance value between the electrodes.
In the environmental test, "x (poor)" indicates that the resistance value increase exceeds 5%, "○ (good)" indicates that the resistance value increase is suppressed to 4% or less, and further increases the resistance value by 3. % or less was judged as "very good".

<Cu corrosion resistance>
On a glass of 60 × 45 mm and a thickness of 0.7 mm, under the patterning conditions of line width 70 μm/line spacing 30 μm (patterning accuracy ±8 μm), line length 46 cm, electrode size 5 mm square, and distance between electrodes 50 mm, ITO 1300 Å and Cu 3000 Å. A substrate for evaluation of Cu corrosion resistance was prepared by forming films in order.
For each of the pre-cured transparent double-sided pressure-sensitive adhesive sheets, the single-sided release film was peeled off, and the sheet was roll-bonded to a PET film (Diafoil T100 manufactured by Mitsubishi Chemical Corporation, thickness 50 μm), and then cut to a width of 52 mm.
After that, the release sheet on the other side was peeled off, and the substrate was laminated with a roll so that the adhesive sheet was positioned between the electrodes. Finished and pasted.
After that, light was irradiated from the PET film side with a high-pressure mercury lamp so that the integrated amount of light at a wavelength of 365 nm was 3000 mJ/cm ² for photocuring (main cured product).
After that, by aging at room temperature for 12 hours, a sample for Cu corrosion resistance evaluation as shown in FIG. 1 was produced.

This sample was subjected to an environmental test under a moist heat environment of 65° C. and 90% RH×500 hours to confirm an increase in the resistance value between the electrodes.
In the environmental test, "× (poor)" indicates that the resistance value increase exceeds 5%, "○ (good)" indicates that the resistance value increase is suppressed to 3% or less, and the resistance value increase is 1. % or less was judged as "very good".

Table 1 shows the evaluation results of Examples and Comparative Examples.
In addition, in each example and comparative example of Table 1, the numerical value described in each item of an adhesive resin composition is a mass part.

Transparent double-sided pressure-sensitive adhesive sheet laminates 1-5 of Examples 1-5 have two or more continuous pressure-sensitive adhesive layers with different shear storage elastic moduli (G') at a temperature of 25 ° C. Since the acrylic copolymer (A) is used, the shear storage modulus (G') at a temperature of 25 ° C. is 100 kPa or more and 500 kPa or less, and the glass transition temperature (Tg) is 0 ° C. or less, cutting processing In particular, it was excellent in punching workability of complicated shapes, adhesive performance at low temperatures, and lamination reliability under cold and hot conditions, while having excellent flexibility, step absorbability, adhesive strength, and metal corrosion resistance.
Among them, the transparent double-sided pressure-sensitive adhesive sheet laminates of Examples 1 to 3 have particularly improved step absorbability and metal resistance by selecting the combination of the surface layer and the middle layer, selecting the layer thickness ratio, and using the rust inhibitor (D) in combination. It was excellent in corrosive performance.

On the other hand, in the transparent double-sided pressure-sensitive adhesive sheet 6 of Comparative Example 1, the composition of the (meth)acrylic copolymer (A) was adjusted, and the storage elastic modulus at 25° C. was 100 kPa or more and 500 kPa with a single-layer pressure-sensitive adhesive sheet. It is designed below.
Although this transparent double-sided pressure-sensitive adhesive sheet 6 is excellent in punching workability into complicated shapes, it has a high Tg and is inferior in adhesive performance at low temperatures and bonding reliability under cold and hot conditions.

In addition, as in the transparent double-sided pressure-sensitive adhesive sheets 7 and 8 of Comparative Examples 2 and 3, in a single-layer design using a specific (meth)acrylic copolymer (A), cutting workability and adhesive performance are balanced. It was difficult to convert

Furthermore, the transparent double-sided pressure-sensitive adhesive sheet laminate 6 of Comparative Example 4 has two or more continuous pressure-sensitive adhesive layers with different shear storage elastic moduli (G′) at a temperature of 25° C., and has a specific (meth)acrylic Although it is designed using the copolymer (A), the type and number of parts of the cross-linking agent in the second adhesive layer (middle layer) are different, so the middle layer elastic modulus is not sufficiently high, so the storage elastic modulus at 25 ° C. is less than 100 kPa, and although it has excellent basic adhesion performance, it cannot be used because of its poor yield when punching complicated shapes.

Claims (14)

It is formed from a pressure-sensitive adhesive resin composition containing a (meth)acrylic copolymer (A) and has two or more continuous pressure-sensitive adhesive layers with different shear storage elastic moduli (G') at a temperature of 25 ° C. death,
The (meth)acrylic copolymer (A) substantially does not contain structural units derived from a carboxyl group-containing (meth)acrylate monomer, and as a monomer component constituting the copolymer (A), Any one or more polar group-containing (meth)acrylate monomers (a2) selected from the group consisting of hydroxyl group-containing (meth)acrylate monomers and nitrogen atom-containing (meth)acrylate monomers, and other than (a2) , a low Tg (meth)acrylate monomer (a1) having a glass transition temperature (Tg) of less than −30° C. when a homopolymer is formed from the monomer components,
The shear storage modulus (G') of the pressure-sensitive adhesive sheet at a temperature of 25°C is 100 kPa or more and 500 kPa or less, and the glass transition temperature defined by the peak temperature of the loss tangent (Tan δ) obtained by dynamic viscoelasticity measurement. A photocurable pressure-sensitive adhesive sheet having a (Tg) of 0° C. or lower. At least one pressure-sensitive adhesive layer (referred to as "first pressure-sensitive adhesive layer") among the two or more continuous pressure-sensitive adhesive layers has a shear storage modulus (G') at a temperature of 25 ° C. 2. The photocurable pressure-sensitive adhesive sheet according to claim 1, which is lower than the layer (referred to as "second pressure-sensitive adhesive layer"). 1 or 2, wherein the continuous two or more pressure-sensitive adhesive layers have a three-layer structure in which the first pressure-sensitive adhesive layer, the second pressure-sensitive adhesive layer and the first pressure-sensitive adhesive layer are laminated in this order. 2. The photocurable pressure-sensitive adhesive sheet according to 2 above. The photocurable pressure-sensitive adhesive sheet according to claim 2 or 3, wherein the second pressure-sensitive adhesive layer is formed from a pressure-sensitive adhesive resin composition having a higher content of the cross-linking agent (B) than the first pressure-sensitive adhesive layer. The photocurable pressure-sensitive adhesive sheet according to any one of claims 2 to 4, wherein the first pressure-sensitive adhesive layer is formed from a pressure-sensitive adhesive resin composition that does not contain a cross-linking agent (B). The photocurable adhesive according to any one of claims 2 to 5, wherein the ratio (t2/t1) of the thickness t1 of the first adhesive layer and the thickness t2 of the second adhesive layer is 1 or more. sheet. The photocurable pressure-sensitive adhesive sheet according to any one of claims 1 to 6, which contains 0.3% by mass or more of the photoinitiator (C) with respect to the total mass of the pressure-sensitive adhesive layer. The photocurable pressure-sensitive adhesive sheet according to any one of claims 1 to 7, which has a loss tangent (Tan δ) at a temperature of 70°C of 0.45 or more and 0.75 or less. A photocurable adhesive sheet with a release sheet, comprising a release sheet and the photocurable adhesive sheet according to any one of claims 1 to 8. An optical film with a photocurable pressure-sensitive adhesive sheet, comprising, in this order, a release sheet, the photocurable pressure-sensitive adhesive sheet according to any one of claims 1 to 8, and an optical film. 11. The optical film with a photocurable pressure-sensitive adhesive sheet according to claim 10, wherein the optical film is any one selected from the group consisting of a polarizing film, a retardation film, a retardation film, an optical compensation film and a brightness enhancement film. The photocurable adhesive sheet according to any one of claims 1 to 8 is used, and two constituent members for an image display device are laminated via the photocurable adhesive sheet, A laminate for constituting an image display device,
At least one of the two constituent members for an image display device is a member selected from the group consisting of a polarizing plate, a liquid crystal display panel, an organic EL display panel, a plasma display panel, a touch panel, and a protective panel. A laminate for constituting an image display device. 13. The laminate for constituting an image display device according to claim 12, wherein the photocurable pressure-sensitive adhesive sheet after lamination has a loss tangent (Tan[delta]) at a temperature of 70[deg.] C. of 0.15 or more and less than 0.45. 14. An image display device comprising the laminate for constituting an image display device according to claim 12 or 13.

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