WO2020162520A1

WO2020162520A1 - Adhesive sheet, adhesive sheet with release sheet, layered product, and production method for layered product

Info

Publication number: WO2020162520A1
Application number: PCT/JP2020/004468
Authority: WO
Inventors: 山本　真之; 貴迪山口
Original assignee: 王子ホールディングス株式会社
Priority date: 2019-02-08
Filing date: 2020-02-06
Publication date: 2020-08-13
Also published as: JP2020128491A; TW202039742A; JP7247623B2; TWI820299B

Abstract

The present invention provides an adhesive sheet that can exhibit superior adhesion to a base material and superior durability even under high-temperature and high-humidity conditions, and has superior workability. The present invention is specifically an adhesive sheet having an adhesive agent layer containing an adhesive agent composition in a half-cured state, wherein the adhesive agent composition contains a crosslinkable acrylic copolymer A having an acidic component, a crosslinking agent B, a polyfunctional monomer C having two or more reactive double bonds in the molecule, a monofunctional monomer D having a reactive double bond in the molecule, and a photopolymerization initiator E, the crosslinkable acrylic copolymer A has a glass transition temperature (Tg) of -40°C or higher, the adhesive agent layer is post-curable, and, when the adhesive agent layer is irradiated with actinic radiation in a cumulative light amount of 3000 mJ/cm2 for post-curing, the adhesive agent layer satisfies physical properties (1) and (2). Physical Property (1): The elongation at break is less than 500% as measured in tensile testing at a rate of elongation of 10 mm/min. Physical property (2): The constant-load peel distances at i) 85°C and a relative humidity of 85% and at ii) 85°C and a relative humidity of less than 10% are each 50 mm or less under the following conditions. (Measurement conditions) A region having a width of 25 mm and a length of 75 mm of the adhesive surface of the adhesive agent layer measuring 25 mm wide and 100 mm long is attached to an adherend, and is allowed to undergo post-curing. The adherend is fixed horizontally such that the non-attached region of the adhesive agent layer hangs downward in each of the environments: i) 85°C and a relative humidity of 85%; and ii) 85°C and a relative humidity of less than 10%. A load of 100 g is applied to an end in the length direction of the non-attached region of the adhesive agent layer for 5 minutes, during which the distance over which the attached region of the adhesive agent layer is released from the adherend is measured as respective constant-load peel distances at i) 85°C and a relative humidity of 85% and at ii) 85°C and a relative humidity of less than 10%.

Description

Adhesive sheet, adhesive sheet with release sheet, laminate and method for producing laminate

The present invention relates to a pressure-sensitive adhesive sheet, a pressure-sensitive adhesive sheet with a release sheet, a laminate, and a method for manufacturing the laminate.

Conventionally, a display device such as a liquid crystal display (LCD) and an input device such as a touch panel used in combination with the display device have been widely used. In the manufacture of these display devices and input devices, transparent adhesive sheets are used for the purpose of bonding optical members, and transparent adhesive sheets are also used for bonding display devices and input devices. ..

The pressure-sensitive adhesive composition that forms the pressure-sensitive adhesive sheet for optical members is manufactured by a known polymerization method. Examples of this polymerization method include solution polymerization, bulk polymerization, suspension polymerization, and emulsion polymerization. Among them, since an easily transparent and optically transparent pressure-sensitive adhesive sheet can be manufactured, a solvent is used for the pressure-sensitive adhesive layer. A pressure-sensitive adhesive sheet using a pressure-sensitive adhesive is widely used. Examples of the solvent-type adhesive include those containing acrylic resin as a main component. Such an acrylic resin can be obtained by a polymerization reaction in a solvent in which an acrylic monomer is dissolved by a method called solution polymerization. In solution polymerization, the molecular weight of the polymer increases as the polymerization proceeds, and the viscosity of the reaction solution increases.Therefore, there is a technical limit to the synthesis of a polymer having the molecular weight necessary to obtain the cohesive force required as an adhesive. There is. Therefore, in order to secure the cohesive force required for the pressure-sensitive adhesive, a crosslinking agent capable of reacting with an acrylic resin such as an isocyanate compound and an epoxide compound has been blended in the pressure-sensitive adhesive composition. Such a cross-linking agent builds a cross-linking network by reacting with the acrylic resin over time and enhances the cohesive force of the pressure-sensitive adhesive layer.

Further, as a method for forming a pressure-sensitive adhesive sheet for an optical member, there is a case where a method of curing by two-step curing in which crosslinking by heat (or active energy rays) and then polymerization by active energy rays (or heat) is used. is there. Since such a pressure-sensitive adhesive sheet is formed from a pressure-sensitive adhesive composition having both thermosetting property and active energy ray-curable property (hereinafter, also referred to as “dual-curable pressure-sensitive adhesive composition”), the thermosetting property can be improved. And has active energy ray curability. Therefore, before bonding with the adherend, it is possible to develop hardness that is easy to handle by, for example, only performing thermosetting, and then after bonding with the adherend, the active energy is further increased. It can be firmly adhered to the adherend by being cured with a wire (called post-curing or after-cure).

For example, in Patent Document 1, a base polymer (A) containing a non-crosslinkable (meth)acrylic acid ester unit (a1) and an acrylic monomer unit (a2) having a crosslinkable functional group, and lauryl acrylate (b1). Containing a monomer (B), a cross-linking agent (C) that reacts with the base polymer (A) by heat, and a polymerization initiator (D that initiates a polymerization reaction of the monomer (B) by irradiation with an active energy ray. ) And a solvent (E), the pressure-sensitive adhesive sheet containing the pressure-sensitive adhesive layer obtained by semi-curing by heating. Further, Patent Document 2 discloses a pressure-sensitive adhesive sheet having at least one UV-curable pressure-sensitive adhesive layer. Here, the storage elastic modulus G′ (1 Hz) at a measurement temperature of 20° C. and a frequency of 1 Hz after ultraviolet curing of the pressure-sensitive adhesive layer is 1×10 ⁴ to 1×10 ⁶ Pa.

JP, 2016-084391, A JP, 2012-031059, A

However, when the present inventors examined the characteristics of the pressure-sensitive adhesive sheets described in Patent Documents 1 and 2, the base material adhesion and durability may be insufficient, and particularly under high temperature and high humidity conditions, the base material It has been found that the adhesion and durability may not be sufficiently obtained. Further, the workability after curing may be insufficient in some cases, and there is room for improvement.

Therefore, in order to solve the problems of the conventional techniques, the present inventors have developed a pressure-sensitive adhesive sheet that can exhibit excellent substrate adhesion and durability even under high temperature and high humidity conditions, and has excellent processability. We proceeded with the aim of providing a pressure-sensitive adhesive sheet.

As a result of repeated intensive studies to achieve the above-mentioned objects, the present inventors have found that a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer in which the pressure-sensitive adhesive composition is in a semi-cured state, wherein the pressure-sensitive adhesive composition contains an acid component The specific crosslinkable acrylic copolymer A, the crosslinking agent B, the polyfunctional monomer C having two or more reactive double bonds in the molecule, and the monofunctional monofunctional monomer having one reactive double bond in the molecule. The present invention has been completed by finding that an adhesive sheet containing a monomer D and a photopolymerization initiator E and satisfying a specific physical property group can achieve the above object.

That is, the present invention relates to the following pressure-sensitive adhesive sheet, pressure-sensitive adhesive sheet with a release sheet, a laminate, and a method for producing a laminate.
1. A pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer in which the pressure-sensitive adhesive composition is in a semi-cured state,
The pressure-sensitive adhesive composition comprises a cross-linkable acrylic copolymer A having an acid component, a cross-linking agent B, a polyfunctional monomer C having two or more reactive double bonds in the molecule, and a reactive double bond in the molecule. Containing a monofunctional monomer D having one bond and a photopolymerization initiator E,
The glass transition temperature (Tg) of the crosslinkable acrylic copolymer A is −40° C. or higher,
The pressure-sensitive adhesive layer has a post-curing property,
A pressure-sensitive adhesive sheet that satisfies the following physical properties (1) and (2) when the pressure-sensitive adhesive layer is post-cured by irradiating the pressure-sensitive adhesive layer with active energy rays so that the integrated light amount becomes 3000 mJ/cm ² .
Physical properties (1): breaking elongation in a tensile test measurement at a tensile speed of 10 mm/min is less than 500%;
Physical Properties (2): Each constant load peeling distance at i) 85° C., relative humidity 85%, and ii) at 85° C., relative humidity less than 10% is 50 mm or less measured under the following measurement conditions:
(Measurement condition)
A region having a width of 25 mm and a length of 75 mm on the adhesive surface of the adhesive layer having a width of 25 mm and a length of 100 mm is attached to an adherend and post-cured. i) 85° C., 85% relative humidity, and ii) 85° C., less than 10% relative humidity In each environment, the adherend is fixed horizontally so that the non-bonded region of the adhesive layer hangs downward. .. A load of 100 g is applied to the end portion in the length direction of the non-bonded region of the pressure-sensitive adhesive layer for 5 minutes, and the distance at which the bonded region of the pressure-sensitive adhesive layer is separated from the adherend is i) 85° C. and relative humidity of 85%. , And ii) Measured as each constant load peel distance at 85° C. and relative humidity of less than 10%.
2. Item 2. The pressure-sensitive adhesive sheet according to Item 1, wherein the content of the monofunctional monomer D is 10 to 40 parts by mass based on 100 parts by mass of the crosslinkable acrylic copolymer A.
3. Item 3. The pressure-sensitive adhesive sheet according to Item 1 or 2, wherein the content of the polyfunctional monomer C is 10 to 40 parts by mass with respect to 100 parts by mass of the crosslinkable acrylic copolymer A.
4. Item 4. The pressure-sensitive adhesive sheet according to any one of Items 1 to 3, wherein the crosslinkable acrylic copolymer A has an acid value of 1 mgKOH/g or more.
5. Item 5. The pressure-sensitive adhesive sheet according to any one of Items 1 to 4, wherein the difference between the gel fraction in the semi-cured state of the pressure-sensitive adhesive layer and the gel fraction after post-curing is 15% or more.
6. A pressure-sensitive adhesive sheet with a release sheet, comprising a pair of release sheets having different release forces on both sides of the pressure-sensitive adhesive sheet according to any one of items 1 to 5.
7. A laminate having the pressure-sensitive adhesive sheet according to any one of items 1 to 5 and an adherend provided on at least one surface side of the pressure-sensitive adhesive sheet, wherein the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet is an active energy ray. A laminate which has been post-cured by irradiation with.
8. Step 1 of laminating an adherend on at least one surface side of the pressure-sensitive adhesive sheet according to any one of the above items 1 to 5, and the pressure-sensitive adhesive layer by irradiating the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet with active energy rays. The manufacturing method of a laminated body which has the process 2 of post-curing in order.

According to the present invention, it is possible to obtain a pressure-sensitive adhesive sheet that exhibits excellent substrate adhesion and durability even under high temperature and high humidity conditions and that has excellent processability.

It is a schematic diagram showing the section of the adhesive sheet of the present invention which has a release sheet or a substrate. It is a schematic diagram showing the section of an example of the layered product of the present invention. It is a schematic diagram showing the section of other examples of the layered product of the present invention. It is a figure explaining the measuring method of the constant load peeling distance in this invention.

The present invention will be described in detail below. The description of the constituent elements described below may be made based on typical embodiments or specific examples, but the present invention is not limited to such embodiments. In the present specification, the numerical range represented by “to” means a range including the numerical values before and after “to” as the lower limit value and the upper limit value.

In addition, in this specification, "(meth)acrylate" represents both acrylate and methacrylate or either, and "(meth)acrylic acid" represents both acrylic acid and methacrylic acid.
Further, in the present specification, “monomer” and “monomer” have the same meaning, and “polymer” and “polymer” have the same meaning.

<Adhesive sheet>
The pressure-sensitive adhesive sheet of the present invention has a pressure-sensitive adhesive layer obtained by semi-curing the pressure-sensitive adhesive composition. The pressure-sensitive adhesive composition comprises a crosslinkable acrylic copolymer A having an acid component, a crosslinker B, a polyfunctional monomer C having two or more reactive double bonds in the molecule, and a reactive double bond in the molecule. Containing a monofunctional monomer D having one and a photopolymerization initiator E,
The glass transition temperature (Tg) of the crosslinkable acrylic copolymer A is −40° C. or higher,
The pressure-sensitive adhesive layer has a post-curing property,
The adhesive layer satisfies the following physical properties (1) and (2) when it is post-cured by irradiating the adhesive layer with active energy rays so that the integrated light amount becomes 3000 mJ/cm ² .
Physical properties (1): breaking elongation in a tensile test measurement at a tensile speed of 10 mm/min is less than 500%;
Physical Properties (2): Each constant load peeling distance at i) 85° C., relative humidity 85%, and ii) at 85° C., relative humidity less than 10% is 50 mm or less measured under the following measurement conditions:
(Measurement condition)
A region having a width of 25 mm and a length of 75 mm on the adhesive surface of the adhesive layer having a width of 25 mm and a length of 100 mm is attached to an adherend and post-cured. i) 85° C., 85% relative humidity, and ii) 85° C., less than 10% relative humidity In each environment, the adherend is fixed horizontally so that the non-bonded region of the adhesive layer hangs downward. .. A load of 100 g is applied to the end portion in the length direction of the non-bonded region of the pressure-sensitive adhesive layer for 5 minutes, and the distance at which the bonded region of the pressure-sensitive adhesive layer is separated from the adherend is i) 85° C. and relative humidity of 85%. , And ii) Measured as each constant load peel distance at 85° C. and relative humidity of less than 10%. The constant load peeling distance under the condition i) indicates high temperature and high humidity base material adhesion, and the constant load peeling distance under the condition ii) indicates high temperature base material adhesion.

The pressure-sensitive adhesive sheet of the present invention having the above structure exhibits excellent substrate adhesion and durability even under high temperature and high humidity conditions, and also has excellent processability. The effect of the present invention is that the crosslinkable acrylic copolymer A contained in the pressure-sensitive adhesive composition has an acid component, has a glass transition temperature (Tg) of −40° C. or higher, and has the above-mentioned physical properties (1). ) And (2) are satisfied. In particular, it is considered that the crosslinkable acrylic copolymer A having an acid component enhances the uniformity of the crosslinked structure formed in the crosslinkable acrylic copolymer A, and thereby enhances the durability of the pressure-sensitive adhesive sheet. Further, since the crosslinkable acrylic copolymer A has an acid component, the adhesiveness between the adhesive sheet and the adherend (adhesiveness to the base material) is increased, which also enhances the durability of the adhesive sheet. Conceivable. Further, by satisfying the condition of the above physical property (1), the pressure-sensitive adhesive layer after post-curing has an appropriate hardness and is excellent in processability.

In this specification, the durability of the pressure-sensitive adhesive sheet can be evaluated by the following method. First, a triacetyl cellulose film is attached to one surface of the pressure-sensitive adhesive sheet, and a polycarbonate plate is attached to the other surface, and active energy rays are irradiated from the surface on the side of the triacetyl cellulose film so that the accumulated light amount becomes 3000 mJ/cm ^2. And the adhesive layer is post-cured. Then, the pressure-sensitive adhesive sheet is allowed to stand for 240 hours under the environment of i) 85° C. and relative humidity of 85%, and ii) environment of 85° C. and relative humidity of less than 10%, respectively. After that, the pressure-sensitive adhesive sheet is observed, and it can be determined that the durability is excellent when floating or peeling from the polycarbonate plate and/or the triacetyl cellulose film is suppressed. The determination of the condition i) indicates high temperature and high humidity durability, and the determination of the condition ii) indicates high temperature durability.

Further, in the pressure-sensitive adhesive sheet of the present invention, post-curing end surface stickiness is suppressed, and for example, adhesion of the pressure-sensitive adhesive to the punching blade during punching and deformation of the pressure-sensitive adhesive layer accompanying it can be prevented. .. Furthermore, the pressure-sensitive adhesive sheet of the present invention does not cause deformation, protrusion, peeling, etc. of the pressure-sensitive adhesive layer when it is subjected to punching to a desired size after post-curing and then cutting for the purpose of aligning the end faces, and also has processability. Are better.

<Structure of adhesive sheet>
The pressure-sensitive adhesive sheet of the present invention has a pressure-sensitive adhesive layer. The pressure-sensitive adhesive sheet may be a single-layer pressure-sensitive adhesive sheet composed only of a pressure-sensitive adhesive layer. The pressure-sensitive adhesive sheet may be a single-sided pressure-sensitive adhesive sheet having a substrate (preferably a transparent substrate) on one side, or a double-sided pressure-sensitive adhesive sheet. As the pressure-sensitive adhesive sheet, a single-layer pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive layer, a multi-layer pressure-sensitive adhesive sheet in which a plurality of pressure-sensitive adhesive layers are laminated, and a multi-layer pressure-sensitive adhesive sheet in which another pressure-sensitive adhesive layer is laminated between pressure-sensitive adhesive layers , A multi-layered pressure-sensitive adhesive sheet in which a support is laminated between the pressure-sensitive adhesive layer and the pressure-sensitive adhesive layer, and a multi-layered pressure-sensitive adhesive sheet in which the pressure-sensitive adhesive layer is laminated on one side of the support and the other pressure-sensitive adhesive layer is laminated on the other side. Can be mentioned. When the double-sided pressure-sensitive adhesive sheet has a support, it is preferable to use a transparent support as the support. As the support, a general film used in the optical field, like the transparent substrate, can be used. Since such a double-sided PSA sheet is excellent in transparency as a whole PSA sheet, it can be suitably used for bonding optical members to each other.

When the pressure-sensitive adhesive sheet of the present invention is a single-sided pressure-sensitive adhesive sheet, as shown in FIG. 1, the pressure-sensitive adhesive layer 11 may be provided with a transparent substrate 12a on one side. In this case, the other surface of the adhesive layer 11 is preferably covered with the release sheet 12b. When using a pressure-sensitive adhesive sheet, the release sheet 12b may be peeled off and bonded so that the pressure-sensitive adhesive layer 11 adheres to a desired adherend, and then post-curing may be performed by irradiating with active energy rays. preferable. As the transparent substrate, a general film used in the optical field such as a polyethylene terephthalate film, an acrylic film, a polycarbonate film, a triacetyl cellulose film, a cycloolefin polymer film can be used. Further, an easy adhesion layer may be provided on the adhesive layer side of these transparent substrates. Further, a functional layer such as a hard coat layer, an antireflection layer, an antifouling layer, and an ultraviolet absorbing layer may be provided on the surface of the transparent substrate opposite to the adhesive layer.

The present invention may relate to a pressure-sensitive adhesive sheet with a release sheet, which comprises release sheets on both sides of the pressure-sensitive adhesive sheet. When the release sheet is provided on both sides of the pressure-sensitive adhesive sheet of the present invention, it is preferable to have

release sheets

12a and 12b on both sides of the pressure-sensitive adhesive layer 11 as shown in FIG.

As the release sheet, a peelable laminated sheet having a release sheet base material and a release agent layer provided on one surface of the release sheet base material, or a polyolefin film such as a polyethylene film or a polypropylene film as a low polarity base material. Are listed.

Papers and polymer films are used as the base material for the release sheet in the release laminate sheet. As the release agent constituting the release agent layer, for example, a general-purpose addition type or condensation type silicone type release agent or a long chain alkyl group-containing compound is used. In particular, an addition type silicone release agent having high reactivity is preferably used.

Specific examples of the silicone-based release agent include BY24-4527 and SD-7220 manufactured by Toray Dow Corning Silicone, and KS-3600, KS-774, X62-2600 manufactured by Shin-Etsu Chemical Co., Ltd. To be Further, the silicone release agent may contain a silicone resin which is an organic silicon compound having SiO ₂ units and (CH ₃ ) ₃ SiO _1/2 units or CH ₂ ═CH(CH ₃ ) SiO _1/2 units. preferable. Specific examples of the silicone resin include BY24-843, SD-7292, SHR-1404 manufactured by Toray Dow Corning Silicone Co., Ltd., and KS-3800, X92-183 manufactured by Shin-Etsu Chemical Co., Ltd.

A commercially available product may be used as the peelable laminated sheet. For example, a heavy separator film, which is a release-treated polyethylene terephthalate film manufactured by Teijin DuPont Films, and a light separator film, which is a release-treated polyethylene terephthalate film manufactured by Teijin DuPont Films, can be mentioned.

When the pressure-sensitive adhesive sheet of the present invention is a double-sided pressure-sensitive adhesive sheet, it is preferable to have a pair of release sheets having different release forces. That is, it is preferable that the release sheet has different releasability between the release sheet 12a and the release sheet 12b in order to facilitate the release. When the releasability from one side and the releasability from the other are different, it becomes easier to first release only the release sheet having the higher releasability. In that case, the releasability of the release sheet 12a and the release sheet 12b may be adjusted according to the attaching method and the attaching order.

The present invention may also relate to an adhesive sheet with a transparent film, which comprises a transparent film on at least one surface of the adhesive sheet. In this case, the transparent film is preferably at least one selected from polyethylene terephthalate film, acrylic film, polycarbonate film, triacetyl cellulose film and cycloolefin polymer film. The transparent film-attached pressure-sensitive adhesive sheet may be a sheet in which a transparent film/pressure-sensitive adhesive sheet/release sheet are laminated in this order.

<Adhesive layer>
The pressure-sensitive adhesive sheet of the present invention has a pressure-sensitive adhesive layer obtained by semi-curing the pressure-sensitive adhesive composition, and the pressure-sensitive adhesive layer has post-curability.

Here, in the present specification, when the gel fraction of the pressure-sensitive adhesive layer is increased by 10 mass% or more by irradiating the active energy ray under the following conditions, the pressure-sensitive adhesive layer before irradiation is in a semi-cured state. And In this case, an optical transparent PET separator is attached to both surfaces of the pressure-sensitive adhesive layer, and the active energy ray (high pressure mercury lamp or metal halide lamp) from one optical transparent PET separator side has an integrated light amount of 3000 mJ/cm ^2. Irradiate.

Among them, the gel fraction in the semi-cured state of the pressure-sensitive adhesive layer is preferably 10% by mass or more and less than 75% by mass, more preferably 12% by mass or more and less than 75% by mass, and 15 to 70% by mass. Is more preferable. The gel fraction of the pressure-sensitive adhesive layer after post-curing is preferably 60 to 100% by mass, more preferably 65 to 100% by mass, and even more preferably 70 to 100% by mass. The difference between the gel fraction in the semi-cured state of the pressure-sensitive adhesive layer and the gel fraction after post-curing is preferably 15% or more, and more preferably 20% or more.

The gel fraction of the pressure-sensitive adhesive layer is a value measured by the following method. First, about 0.1 g of the adhesive sheet (adhesive layer) is collected in a sample bottle, 30 ml of ethyl acetate is added, and the mixture is shaken for 24 hours. Then, the contents of this sample bottle are filtered by a 150-mesh stainless steel wire net, and the residue on the wire net is dried at 100° C. for 1 hour to measure the dry mass (g). From the obtained dry mass, the gel fraction is calculated by the following formula 1.
Gel fraction (mass %)=(dry mass/collected mass of adhesive layer)×100...Equation 1

In the present specification, the “semi-cured state” is preferably the state after heat curing. Then, after that, it is preferable to perform "post-curing" by irradiating with active energy rays. That is, the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet of the present invention is preferably in a semi-cured state by thermosetting the pressure-sensitive adhesive composition and preferably has active energy ray curability.

When the pressure-sensitive adhesive layer is post-cured by irradiating the pressure-sensitive adhesive layer with active energy rays so that the integrated light amount becomes 3000 mJ/cm ² , the pressure-sensitive adhesive layer satisfies the following physical properties (1) and (2);
Physical properties (1): breaking elongation in a tensile test measurement at a tensile speed of 10 mm/min is less than 500%;
Physical Properties (2): Each constant load peeling distance at i) 85° C., relative humidity 85%, and ii) at 85° C., relative humidity less than 10% is 50 mm or less measured under the following measurement conditions:
(Measurement condition)
A region having a width of 25 mm and a length of 75 mm on the adhesive surface of the adhesive layer having a width of 25 mm and a length of 100 mm is attached to an adherend and post-cured. i) 85° C., 85% relative humidity, and ii) 85° C., less than 10% relative humidity In each environment, the adherend is fixed horizontally so that the non-bonded region of the adhesive layer hangs downward. .. A load of 100 g is applied to the end portion in the length direction of the non-bonded region of the pressure-sensitive adhesive layer for 5 minutes, and the distance at which the bonded region of the pressure-sensitive adhesive layer is separated from the adherend is i) 85° C. and relative humidity of 85%. , And ii) Measured as each constant load peel distance at 85° C. and relative humidity of less than 10%.

The physical property (1) (elongation at break) may be less than 500%, preferably 490% or less, more preferably 480% or less. Here, the breaking elongation is measured according to JIS K 7161-1. At that time, the tensile speed is 10 mm/min, and the measurement is performed at 23° C. and a relative humidity of 50%. Further, as the measurement sample, a pressure-sensitive adhesive layer having a thickness of 25 μm, a width of 60 mm and a length of 200 mm is rounded in the length direction and processed into a columnar shape having a cross-sectional area of 5 mm ² and a height of 60 mm. This is pulled so that the distance between chucks is 30 mm, and the elongation at which the sample breaks is defined as the breaking elongation. As the measuring device, for example, Autograph AGS-X manufactured by Shimadzu Corporation can be used.

Regarding the measurement of physical property (2) (peeling distance under constant load) in detail, first, a test piece for measurement is prepared by the following method. A triacetyl cellulose film (Fujitac TD60UL, thickness 60 μm, manufactured by FUJIFILM Corporation) is attached to one surface of the adhesive layer using a hand roller to prepare a laminated film. This laminated film was cut into a size of width 25 mm and length 100 mm, and then the other side of the pressure-sensitive adhesive layer had a width of 25 mm and a length of 100 mm. Polycarbonate plate with hard coat layer: Mitsubishi Gas Chemical Co., Inc., Iupilon MR58 (1 mm thickness) is attached to the hard coat surface side using a 2 kg pressure roller. In this state, it is kept in an autoclave under the conditions of 40° C. and 5 atm for 30 minutes to be brought into close contact with the adherend.

In addition, under the above-described measurement conditions, when post-curing is performed, ultraviolet rays are irradiated from the side of the triacetyl cellulose film of the test piece for measurement so that the integrated light amount becomes 3000 mJ/cm ² .

After that, i) 85° C., relative humidity 85%, and ii) 85° C., relative humidity less than 10%, after being left for 24 hours respectively, i) 85° C., relative humidity 85%, and ii) 85° C., Under an environment of less than 10% relative humidity, 100 g of weight 34 is hung at the lengthwise end of the non-bonded region (width 25 mm, length 25 mm) of the laminated film as shown in FIG. A load of 100 g is applied in the direction of 90° with respect to, and the state is left for another 5 minutes. During that time, the length L (constant load peeling distance) of the portion where the laminated film is peeled off is measured.

The constant load peeling distance at i) 85° C. and 85% relative humidity measured under the above measurement conditions is 50 mm or less, preferably 45 mm or less, more preferably 40 mm or less, and 35 mm or less. It is more preferable that the thickness is 30 mm or less, and particularly preferably 30 mm or less. Further, ii) the constant load peeling distance at 85° C. and a relative humidity of less than 10% is 50 mm or less, preferably 45 mm or less, more preferably 40 mm or less, and further preferably 35 mm or less, It is particularly preferably 30 mm or less. The constant load peeling distance at i) 85° C. and relative humidity of 85% and ii) at 85° C. and relative humidity of less than 10% may be 0 mm.

In the present invention, in the case where the adhesive layer is post-cured by irradiating the adhesive layer with active energy rays so that the integrated light amount becomes 3000 mJ/cm ² , the adhesive layer has the following physical properties (1) and (2), It is preferable that the physical property (3) is satisfied.

Physical properties (3): The probe tack value is 1.0 N/5 mmφ or less.

(Probe tack value measurement conditions)
Measuring equipment: NS probe tack tester (Nichiban)
Probe diameter: 5mmφ
Probe base material: Stainless steel surface finish AA#400 Mirror surface weight by polishing: 19.6±0.2g (made of brass)
Probe moving speed: 1.0 cm/sec Duel time: 1 sec

The probe tack value of the pressure-sensitive adhesive layer after the post-curing is more preferably 1.0 N/5 mmφ or less, further preferably 0.5 N/5 mmφ or less. The lower limit of the probe tack value is not particularly limited, and is preferably 0.1 N/5 mmφ or more, more preferably 0.01 N/5 mmφ or more, for example. When the probe tack value of the pressure-sensitive adhesive layer after post-curing is within the above range, workability is excellent and workability is also good.

The thickness of the pressure-sensitive adhesive layer can be appropriately set depending on the application and is not particularly limited, but is preferably 5 to 150 μm, more preferably 8 to 100 μm, and particularly preferably 10 to 80 μm. By setting the thickness of the pressure-sensitive adhesive layer within the above range, the pressure-sensitive adhesive can be prevented from sticking out and stickiness, so that the processability can be improved. Furthermore, when the thickness of the pressure-sensitive adhesive layer is within the above range, the double-sided pressure-sensitive adhesive sheet can be easily manufactured.

<Adhesive composition>
The above-mentioned pressure-sensitive adhesive layer is obtained by semi-curing the pressure-sensitive adhesive composition. The pressure-sensitive adhesive composition used in the present invention is a dual-curable pressure-sensitive adhesive composition. The pressure-sensitive adhesive composition is a cross-linkable acrylic copolymer A having an acid component (however, the glass transition temperature (Tg) is −40° C. or higher), a cross-linking agent B, and a polyfunctional compound having two or more reactive double bonds in the molecule. It contains a monomer C, a monofunctional monomer D having one reactive double bond in the molecule, and a photopolymerization initiator E.

(Crosslinkable acrylic polymer A)
The crosslinkable acrylic polymer A is not particularly limited as long as it has an acrylic monomer unit containing an acid component and has a glass transition temperature (Tg) of −40° C. or higher. It is preferable that the functional (meth)acrylic acid ester unit (a1) and the acrylic monomer unit (a2) having an acid component and having a crosslinkable functional group are copolymerized. The crosslinkable acrylic polymer A is preferably one having transparency to such an extent that the visibility of the display device is not deteriorated. In addition, in the present specification and claims, the “unit” is a repeating unit (monomer unit) constituting a polymer.

The non-crosslinkable (meth)acrylic acid ester unit (a1) is a repeating unit derived from a (meth)acrylic acid alkyl ester. Examples of alkyl (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, and (meth)acrylate. Isobutyl acrylate, t-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, ( Isooctyl (meth)acrylate, n-nonyl (meth)acrylate, isononyl (meth)acrylate, n-decyl (meth)acrylate, isodecyl (meth)acrylate, n-undecyl (meth)acrylate, (meth) Examples thereof include n-dodecyl acrylate, stearyl (meth)acrylate, methoxyethyl (meth)acrylate, ethoxyethyl (meth)acrylate, cyclohexyl (meth)acrylate, and benzyl (meth)acrylate. These may be used alone or in combination of two or more.

Among the above-mentioned (meth)acrylic acid alkyl esters, at least one selected from methyl (meth)acrylate, n-butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate is preferred because of its high adhesiveness. preferable.

In the present invention, the crosslinkable functional group of the crosslinkable acrylic polymer has an acid component. Here, the crosslinkable functional group serving as an acid component is preferably a carboxyl group or a group derived from a carboxyl group, or a sulfo group or a group derived from a sulfo group, and particularly preferably a carboxy group. That is, the acrylic monomer unit (a2) having a crosslinkable functional group having an acid component is preferably a carboxy group-containing monomer unit. Examples of the carboxy group-containing monomer unit include acrylic acid and methacrylic acid.

Note that the crosslinkable functional group of the crosslinkable acrylic polymer A may have a functional group other than the crosslinkable functional group serving as an acid component. Other functional groups may include hydroxy groups, amino groups, amide groups, glycidyl groups or isocyanate groups.

The content of the acrylic monomer unit (a2) having a crosslinkable functional group having an acid component in the crosslinkable acrylic polymer A is preferably 0.01 to 40% by mass, and 0.5 to 35% by mass. More preferably. When the content of the acrylic monomer unit (a2) having a crosslinkable functional group having an acid component is at least the lower limit value of the above range, the crosslinkability necessary for maintaining a semi-cured state can be sufficiently exhibited, If it is at most the upper limit value of the above range, it is easy to maintain the required tackiness.

The crosslinkable acrylic polymer A may have other monomer units, if necessary. Any other monomer may be used as long as it can be copolymerized with the above-mentioned acrylic monomer, and examples thereof include (meth)acrylonitrile, vinyl acetate, styrene, vinyl chloride, vinylpyrrolidone, and vinylpyridine. The content of the other monomer unit in the crosslinkable acrylic polymer is preferably 20% by mass or less, and more preferably 15% by mass or less.

The glass transition temperature (Tg) of the crosslinkable acrylic polymer A may be −40° C. or higher, preferably −38° C. or higher, and more preferably −35° C. or higher. The upper limit of the glass transition temperature (Tg) is not limited, but may be 0° C. or lower, for example. By setting the glass transition temperature (Tg) of the crosslinkable acrylic polymer A in the above range, the workability of the pressure-sensitive adhesive sheet can be more effectively enhanced.

As the specific glass transition temperature, a literature value may be adopted, or a value obtained by measuring the glass transition temperature of the crosslinkable acrylic polymer A using a DSC (differential scanning calorimeter) may be adopted. ..

The weight average molecular weight of the crosslinkable acrylic polymer A is preferably 100,000 to 2,000,000, more preferably 200,000 to 1,500,000. When the weight average molecular weight is within the above range, the semi-cured state of the pressure-sensitive adhesive layer can be easily maintained, the hardness after post-curing can be easily obtained, and the workability is excellent. The weight average molecular weight of the crosslinkable acrylic polymer A is a value before being crosslinked with a crosslinking agent. The weight average molecular weight is a value measured by size exclusion chromatography (SEC) and determined on a polystyrene basis. As the crosslinkable acrylic polymer, a commercially available one may be used, or one synthesized by a known method may be used.

The acid value of the crosslinkable acrylic polymer A is preferably 1 mgKOH/g or more, more preferably 2 mgKOH/g or more, and further preferably 3 mgKOH/g or more. The acid value of the crosslinkable acrylic polymer A is preferably 200 mgKOH/g or less. In the present invention, the acid value of the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition is also preferably within the above range.

The acid value of the crosslinkable acrylic polymer A is calculated by the following method. First, a precision balance was accurately weighed in a 100 ml Erlenmeyer flask so that the solid content of the crosslinkable acrylic polymer A was about 2 g as a sample, and toluene/2-propanol/water=5/5/0.5. 10 ml of the mixed solvent (weight ratio) is added and dissolved. Then, 1 to 3 drops of p-naphtholbenzene solution as an indicator is added to this container, and the mixture is sufficiently stirred until the sample becomes uniform. This is titrated with a 0.1N potassium hydroxide-2-propanol solution, and the end point of neutralization is when the indicator has been light red for 30 seconds. The value obtained by using the following calculation formula (1) from the result is used as the acid value of the sample.

Acid value (mgKOH/g)=[cKOH×(V1-V0)×5.611]/S (1) In the calculation formula (1), cKOH is the molar concentration of 0.1N potassium hydroxide-2-propanol solution. (Mol/L), V1 is the amount (mL) of the 0.1 mol/L potassium hydroxide-2-propanol solution required for the titration of the sample, and V0 is the 0.1 mol/L required for the titration in the blank test. L is the amount of potassium hydroxide-2-propanol solution (mL), and S is the amount of sample collected (g).

(Crosslinking agent B)
The pressure-sensitive adhesive composition contains a crosslinking agent. The cross-linking agent can be appropriately selected in consideration of the reactivity with the cross-linkable functional group of the cross-linkable acrylic polymer A. For example, it can be selected from known crosslinking agents such as an isocyanate compound, an epoxy compound, an oxazoline compound, an aziridine compound, a metal chelate compound and a butylated melamine compound. Among these, it is preferable to use an epoxy compound because the carboxy group-containing acrylate can be easily crosslinked. That is, the crosslinking agent is preferably a bifunctional or higher functional epoxy compound.

Examples of the epoxy compound include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, glycerin diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol di Glycidyl ether, tetraglycidyl xylylenediamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, trimethylolpropane polyglycidyl ether, diglycerol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitol polyglycidyl ether, etc. Can be mentioned.

The content of the cross-linking agent in the pressure-sensitive adhesive composition is appropriately selected according to the desired tackiness and the like, but is preferably 0.01 to 5 parts by mass with respect to 100 parts by mass of the cross-linkable acrylic polymer, and 0 It is more preferably 0.01 to 3 parts by mass. By setting the content of the cross-linking agent within the above range, the adhesion to the base material can be enhanced and the processability can be further enhanced. As the cross-linking agent, one kind may be used alone or two or more kinds may be used in combination, and when two kinds or more are used in combination, the total mass is preferably within the above range.

(Polyfunctional monomer C)
The pressure-sensitive adhesive composition contains a polyfunctional monomer C having two or more reactive double bonds in the molecule.

Examples of the polyfunctional monomer C include ethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, 1,3-butylene glycol di(meth)acrylate, and di(meth)acrylic acid 1 ,4-butylene glycol, 1,9-nonanediol di(meth)acrylic acid, 1,6-hexanediol diacrylic acid, polybutylene glycol di(meth)acrylic acid, neopentyl glycol di(meth)acrylic acid, di(meth)acrylic acid (Meth)acrylic acid tetraethylene glycol, di(meth)acrylic acid tripropylene glycol, di(meth)acrylic acid polypropylene glycol, bisphenol A diglycidyl ether diacrylate, tri(meth)acrylic acid trimethylolpropane, tri(meth)acrylic acid Examples thereof include (meth)acrylic acid esters of polyhydric alcohols such as pentaerythritol acrylate and pentaerythritol tetra(meth)acrylate, vinyl methacrylate and the like.

The polyfunctional monomer C has two or more reactive double bonds, and above all, it is preferable that the polyfunctional monomer has two or more and less than five reactive double bonds. It is more preferable that the number is one or more and less than four.

A commercially available product can be used as the polyfunctional monomer C. Examples of commercially available products include trifunctional monomer M310 (trimethylolpropane PO modified triacrylate) manufactured by Toagosei Co., Ltd., trifunctional monomer M321 (trimethylolpropane propylene oxide modified triacrylate), bifunctional monomer M211B manufactured by Toagosei Co., Ltd. ( Bisphenol A EO modified diacrylate) and the like.

The polyfunctional monomer C may have a bisphenol skeleton in one molecule. By using a polyfunctional monomer having a bisphenol skeleton in one molecule, the hardness of the pressure-sensitive adhesive layer after post-curing can be more effectively increased, and the workability of the pressure-sensitive adhesive sheet is easily improved.

Examples of such a polyfunctional monomer C include bisphenol A diglycidyl ether diacrylate, propoxylated bisphenol A diacrylate, and bisphenol F diglycidyl ether diacrylate.

The glass transition temperature (Tg) when the polyfunctional monomer C is a homopolymer is preferably 30° C. or higher, and more preferably 50° C. or higher. The glass transition temperature (Tg) when the polyfunctional monomer is a homopolymer may be, for example, 300° C. or lower. By setting the glass transition temperature (Tg) when the polyfunctional monomer C is a homopolymer within the above range, the workability of the pressure-sensitive adhesive sheet can be more effectively enhanced.

The glass transition temperature in this specification is the glass transition temperature when the polyfunctional monomer C is a homopolymer. As a specific glass transition temperature, literature values may be adopted, but after the polyfunctional monomer C is made into a homopolymer having a weight average molecular weight of 10,000 or more, the glass transition temperature of the homopolymer is determined by DSC ( A value measured by using a differential scanning calorimeter may be adopted.

The content of the polyfunctional monomer C in the pressure-sensitive adhesive composition is preferably 10 to 40 parts by mass, more preferably 10 to 30 parts by mass, based on 100 parts by mass of the crosslinkable acrylic polymer A. It is more preferably 10 to 25 parts by mass. The polyfunctional monomer C may be used alone or in combination of two or more kinds. When using two or more kinds in combination, the total mass is preferably within the above range. By setting the content of the polyfunctional monomer C within the above range, the above-mentioned physical properties (1) to (3) can be easily achieved, and the high temperature and high humidity durability can be improved. Furthermore, by setting the content of the polyfunctional monomer C within the above range, the hardness of the pressure-sensitive adhesive layer after post-curing can be more effectively increased, and the workability of the pressure-sensitive adhesive sheet can be increased.

(Monofunctional monomer D)
The pressure-sensitive adhesive composition has the monofunctional monomer D having one reactive double bond in the molecule.

Examples of the monofunctional monomer D include isobornyl acrylate, isostearyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, benzyl methacrylate, N-acryloyloxyethyl hexahydrophthalimide, acrylamide, N,N-dimethylacrylamide, Examples thereof include N,N-diethylacrylamide, acryloylmorpholine, vinylpyrrolidone and the like. Among them, the monofunctional monomer is preferably an alkyl (meth)acrylate, preferably at least one selected from isobornyl acrylate and isostearyl acrylate, and more preferably isobornyl acrylate. preferable. Examples of commercially available monofunctional monomers D include DEAA manufactured by KJ Chemicals, and IBXA manufactured by Osaka Organic Chemical Industry.

The glass transition temperature (Tg) when the monofunctional monomer D is a homopolymer is preferably 50°C or higher and lower than 200°C, more preferably 55°C or higher and lower than 180°C.

The content of the monofunctional monomer D is preferably 10 to 40 parts by mass, more preferably 10 to 30 parts by mass, and 10 to 20 parts by mass with respect to 100 parts by mass of the crosslinkable acrylic polymer A. Is more preferable. As the monofunctional monomer D, one type may be used alone, or two or more types may be used in combination. When two or more types are used in combination, the total mass is preferably within the above range.

(Photopolymerization initiator E)
The pressure-sensitive adhesive composition contains a photopolymerization initiator E. The photopolymerization initiator is preferably one which initiates the polymerization of the crosslinkable acrylic polymer or the polyfunctional monomer by irradiation with active energy rays. As the photopolymerization initiator E, a known photopolymerization initiator can be used.

Here, the term “active energy ray” means an electromagnetic wave or charged particle beam having energy quantum, and examples thereof include ultraviolet rays, electron rays, visible rays, X-rays, and ion rays. Among them, ultraviolet rays or electron beams are preferable, and ultraviolet rays are particularly preferable, from the viewpoint of versatility.

Examples of the photopolymerization initiator E include acetophenone type initiators, benzoin ether type initiators, benzophenone type initiators, hydroxyalkylphenone type initiators, thioxanthone type initiators, amine type initiators, acylphosphine oxide type initiators, etc. Are listed.

Specific examples of the acetophenone-based initiator include diethoxyacetophenone and benzyl dimethyl ketal.

Specific examples of the benzoin ether-based initiator include benzoin and benzoin methyl ether.

Specific examples of the benzophenone-based initiator include benzophenone and methyl o-benzoylbenzoate.

Specific examples of the hydroxyalkylphenone initiator include 1-hydroxy-cyclohexyl-phenyl-ketone (manufactured by BASF Japan Ltd., commercially available as IRGACURE184).

Specific examples of the thioxanthone initiator include 2-isopropylthioxanthone and 2,4-dimethylthioxanthone.

Specific examples of the amine-based initiator include triethanolamine and ethyl 4-dimethylbenzoate.

Specific examples of the acylphosphine oxide initiator include phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (manufactured by BASF Japan Ltd., commercially available as IRGACURE819).

The content of the photopolymerization initiator E in the pressure-sensitive adhesive composition is preferably 0.05 to 10 parts by mass, and 0.1 to 5 parts by mass with respect to 100 parts by mass of the crosslinkable acrylic polymer. Is more preferable. When it is at least the above lower limit, the desired hardness can be adjusted by post-curing, and the molecular weight after post-curing can be adjusted to an appropriate range, so that a pressure-sensitive adhesive sheet having excellent processability can be obtained. As the photopolymerization initiator, one type may be used alone, or two or more types may be used in combination, and when two or more types are used in combination, the total mass is preferably within the above range.

(solvent)
The adhesive composition may contain a solvent. In this case, the solvent is used for improving the coating suitability of the pressure-sensitive adhesive composition. Examples of the solvent include hydrocarbons such as hexane, heptane, octane, toluene, xylene, ethylbenzene, cyclohexane and methylcyclohexane; halogenated hydrocarbons such as dichloromethane, trichloroethane, trichloroethylene, tetrachloroethylene and dichloropropane; methanol, ethanol, Alcohols such as propanol, isopropyl alcohol, butanol, isobutyl alcohol, diacetone alcohol; ethers such as diethyl ether, diisopropyl ether, dioxane, tetrahydrofuran; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, isophorone, cyclohexanone; methyl acetate , Ethyl acetate, butyl acetate, isobutyl acetate, amyl acetate, ethyl butyrate, etc.; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene Examples thereof include polyols such as glycol monomethyl ether acetate and derivatives thereof.

The content of the solvent in the pressure-sensitive adhesive composition is not particularly limited, but is preferably 25 to 500 parts by mass, and more preferably 30 to 400 parts by mass with respect to 100 parts by mass of the crosslinkable acrylic polymer A.

Further, the content of the solvent is preferably 10 to 90% by mass, and more preferably 20 to 80% by mass based on the total mass of the pressure-sensitive adhesive composition. As the solvent, one type may be used alone, or two or more types may be used in combination. When two or more types are used in combination, the total mass is preferably within the above range.

(Other ingredients)
The pressure-sensitive adhesive composition may contain components other than the above components as long as the effects of the present invention are not impaired. Examples of other components include components known as additives for pressure-sensitive adhesives. For example, a plasticizer, an antioxidant, a metal corrosion inhibitor, a tackifier, a silane coupling agent, an ultraviolet absorber, and a light stabilizer such as a hindered amine compound can be selected as necessary. Further, a dye or a pigment may be added for the purpose of coloring.

Examples of the plasticizer include vinyl acetate, vinyl propionate, vinyl butyrate, vinyl caproate, vinyl caprylate, vinyl caprate, vinyl laurate, vinyl myristate, vinyl palmitate, vinyl stearate, vinyl cyclohexanecarboxylate, and benzoic acid. Examples thereof include carboxylic acid vinyl esters such as vinyl, styrene and the like.

Examples of antioxidants include phenolic antioxidants, amine antioxidants, lactone antioxidants, phosphorus antioxidants, sulfur antioxidants and the like. These antioxidants may be used alone or in combination of two or more.

As the metal corrosion inhibitor, a benzotriazole resin can be mentioned as a preferable example because of the compatibility of the pressure-sensitive adhesive and the high effect.

Examples of the tackifier include rosin resin, terpene resin, terpene phenol resin, coumarone indene resin, styrene resin, xylene resin, phenol resin, petroleum resin and the like.

Examples of the silane coupling agent include mercaptoalkoxysilane compounds (eg, mercapto group-substituted alkoxy oligomers).

Examples of ultraviolet absorbers include benzotriazole compounds and benzophenone compounds. However, when ultraviolet rays are used as the active energy rays at the time of post-curing, it is preferable to add them in a range that does not hinder the polymerization reaction.

<Production method of adhesive sheet>
The method for producing a pressure-sensitive adhesive sheet of the present invention includes a step of applying the above-mentioned pressure-sensitive adhesive composition on a release sheet to form a coating film, and a step of heating the coating film to a semi-cured cured product. It is preferable. By heating the coating film, the reaction between the crosslinkable acrylic polymer A and the crosslinking agent B proceeds to form a cured product (adhesive layer) in a semi-cured state. That is, during heating, the polymerization reaction of the monomer by the photopolymerization initiator E does not proceed in the coating film, or even if the polymerization reaction proceeds slightly, it is contained in the adhesive composition in the adhesive layer. At least a part of the monomers C and D and the photopolymerization initiator E is contained in an unreacted state. The pressure-sensitive adhesive sheet of the present invention preferably has post-curability and active energy ray curability.

Note that in order to bring the pressure-sensitive adhesive composition into a semi-cured state, it is preferable to carry out an aging treatment in which the pressure-sensitive adhesive sheet is left standing at a constant temperature for a certain period after the solvent is removed after coating. The aging treatment can be carried out, for example, by allowing it to stand at 23° C. for 7 days.

The coating of the adhesive composition can be carried out using a known coating device. Examples of the coating device include a blade coater, an air knife coater, a roll coater, a bar coater, a gravure coater, a microgravure coater, a rod blade coater, a lip coater, a die coater, and a curtain coater.

A known heating device such as a heating furnace or an infrared lamp can be used to heat the coating film formed by applying the pressure-sensitive adhesive composition.

<How to use the adhesive sheet>
In the method of using the pressure-sensitive adhesive sheet of the present invention, it is preferable to bring the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet into contact with the surface of the adherend. In the method of using the pressure-sensitive adhesive sheet, it is preferable that the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet is bonded to the adherend when the pressure-sensitive adhesive layer is in a semi-cured state, and the pressure-sensitive adhesive layer is post-cured by irradiation with active energy rays. That is, the pressure-sensitive adhesive sheet of the present invention is a two-stage curable pressure-sensitive adhesive sheet, has a pressure-sensitive adhesive layer that is semi-cured only by heat before bonding, and after bonding, the pressure-sensitive adhesive layer is post-cured by active energy rays. To be done.

<Use of adhesive sheet>
The pressure-sensitive adhesive sheet of the present invention is an optical member that requires durability, and is preferably used for bonding optical members that require molding after lamination with the optical member.

The pressure-sensitive adhesive sheet of the present invention is excellent in substrate adhesion and durability even when it is attached to an adherend such as a base material and post-cured, and then exposed to a high temperature and high humidity environment. Therefore, it is possible to suppress the occurrence of floating and peeling. The pressure-sensitive adhesive sheet of the present invention is, for example, bonded to a polycarbonate substrate, post-cured, and then prevented from floating or peeling from the polycarbonate substrate even when exposed to a high temperature and high humidity environment. can do.

The adhesive sheet of the present invention may be attached to an optical member such as a polarizing plate. Here, the polarizing plate includes a polarizer and a polarizer protective film, and the pressure-sensitive adhesive sheet of the present invention is preferably attached to the polarizer protective film. As the polarizer protective film, cycloolefin resin film, cellulose acetate resin film such as triacetyl cellulose and diacetyl cellulose, polyester resin film such as polyethylene terephthalate, polyethylene naphthalate and polybutylene terephthalate, polycarbonate resin film, acrylic Examples thereof include a resin resin film and a polypropylene resin film.

[Laminate]
The present invention also relates to a laminate having the above-mentioned pressure-sensitive adhesive sheet and an adherend. The laminate is a pressure-sensitive adhesive layer after post-curing, which is obtained by irradiating the pressure-sensitive adhesive layer of the above-mentioned pressure-sensitive adhesive sheet with active energy rays, and at least one surface side of the pressure-sensitive adhesive layer after post-curing. Equipped with. That is, the laminate of the present invention is a laminate having a pressure-sensitive adhesive sheet and an adherend provided on at least one surface side of the pressure-sensitive adhesive sheet, and the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet is irradiated with active energy rays. By doing so, it is post-cured. When the pressure-sensitive adhesive sheet is a double-sided pressure-sensitive adhesive sheet, a laminate is formed by irradiating the two adherends with a semi-cured pressure-sensitive adhesive sheet and irradiating them with active energy rays and post-curing the pressure-sensitive adhesive layer. It is preferable. Here, the adherend is more preferably a base material and an optical member, and particularly preferably a polycarbonate base material, a polarizing plate, a transparent film, a transparent resin or glass.

FIG. 2 is a schematic view showing a cross section of an example of the laminate of the present invention. FIG. 2 is a cross-sectional view showing an example of the configuration of the laminate 20 in which the pressure-sensitive adhesive sheet 21 of the present invention is attached to the base material 22 and the optical member 24. As shown in FIG. 2, the pressure-sensitive adhesive sheet 21 of the present invention is preferably used for bonding to the base material 22, and is used for bonding the base material 22 and the other optical member 24. preferable. The pressure-sensitive adhesive sheet 21 of the present invention may be used for bonding with a polarizing plate.

As the optical member included in the laminated body, various constituent members in optical products such as a touch panel and an image display device, and an anti-scattering film attached to the cover lens of the outermost layer can be cited. As a component of the touch panel, for example, an ITO film provided with an ITO film on a transparent resin film, an ITO glass provided with an ITO film on the surface of a glass plate, a transparent conductive film obtained by coating a conductive polymer on a transparent resin film, A hard coat film, a fingerprint resistant film and the like can be mentioned. Examples of constituent members of the image display device include an antireflection film, an alignment film, a polarizing film, a retardation film, and a brightness enhancement film used in a liquid crystal display device.

Materials used for these members include glass, polycarbonate, polyethylene terephthalate, polymethyl methacrylate, polyethylene naphthalate, cycloolefin polymer, triacetyl cellulose, polyimide, cellulose acylate, and the like.

When the pressure-sensitive adhesive sheet of the present invention is a double-sided pressure-sensitive adhesive sheet, it can be used for bonding two adherends. In this case, the pressure-sensitive adhesive sheet of the present invention is a laminate of transparent optical films in a touch panel, a transparent optical film and a glass, a transparent optical film of a touch panel and a liquid crystal panel, a cover glass. And a transparent optical film, or a cover glass and a transparent optical film, and is useful when either member is a polycarbonate substrate. As the transparent optical film, a general film used in the optical field such as a polyethylene terephthalate film, an acrylic film, a polycarbonate film, a triacetyl cellulose film, or a cycloolefin polymer film can be used. A hard coat layer may be provided on the transparent optical film or the polycarbonate substrate.

FIG. 3 is a schematic view showing a cross section of another example of the laminate of the present invention. As shown in FIG. 3, the adherend may have stepped portions (27a, 27b, 27c, 27d). In FIG. 3, the base material has step portions (27a, 27b), and the optical member has step portions (27c, 27d). The thickness of the step portions (27a, 27b, 27c, 27d) is usually 5 to 60 μm. As described above, the pressure-sensitive adhesive sheet 21 of the present invention can be attached to a member having a step portion, and can follow the unevenness generated from the step portion.

[Method for manufacturing laminated body]
The method for producing a laminate includes a step of sticking the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet described above to an adherend in a semi-cured state, and then irradiating an active energy ray to post-cure the pressure-sensitive adhesive layer. That is, the method for producing a laminate of the present invention comprises the step 1 of laminating an adherend on at least one surface side of the pressure-sensitive adhesive sheet, and the pressure-sensitive adhesive by irradiating the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet with active energy rays. Step 2 of sequentially post-curing the layers. Prior to irradiation with active energy rays, the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet is in a semi-cured state, so that the initial adhesion to the substrate is good. In this way, after the pressure-sensitive adhesive sheet is attached to the adherend, the adhesive layer is post-cured with active energy rays, whereby the cohesive force of the pressure-sensitive adhesive layer is increased and the adhesiveness to the adherend is improved. In addition, the post-cured pressure-sensitive adhesive layer can prevent the base material from being deformed or distorted.

The active energy rays include ultraviolet rays, electron rays, visible rays, X rays, ion rays, etc., and can be appropriately selected according to the photopolymerization initiator contained in the adhesive layer. Among them, ultraviolet rays or electron beams are preferable, and ultraviolet rays are particularly preferable, from the viewpoint of versatility.

As the ultraviolet light source, for example, a high pressure mercury lamp, a low pressure mercury lamp, an ultra high pressure mercury lamp, a metal halide lamp, a carbon arc, a xenon arc, an electrodeless ultraviolet lamp, etc. can be used. As the electron beam, for example, an electron beam emitted from each type of electron beam accelerator such as Cockloft-Walt type, Bande-Craft type, resonance transformer type, insulating core transformer type, linear type, dynamitron type, high frequency type, etc. is used. it can.

Radiation output of the UV light, it is preferable that the integrated quantity of light is made to be a 100 ~ 10000mJ / cm ^2, and more preferably made to be 500 ~ 5000mJ / cm ^2. When measuring the above-mentioned physical properties (1) to (3) in the present invention, the active energy ray is irradiated so that the integrated light amount becomes 3000 mJ/cm ² .

The features of the present invention will be described more specifically below with reference to examples and comparative examples. The materials, usage amounts, ratios, processing contents, processing procedures, and the like shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be limitedly interpreted by the following specific examples.

<Synthesis of Crosslinkable Acrylic Polymer A (A-1)>
A crosslinkable acrylic polymer A (A-1) having an acid component was prepared by solution polymerization in ethyl acetate. In detail, butyl acrylate monomer (BA), methyl acrylate monomer (MA), methyl methacrylate (MMA), acrylic acid (AA) are mixed in a mass ratio of 90:1:4:6 to initiate radical polymerization. AIBN (azobisisobutyronitrile) was dissolved in the solution as an agent. The solution was heated to 60° C. and subjected to random copolymerization to obtain a crosslinkable acrylic polymer A (A-1).

The solution viscosity at 23° C. of a 21% by mass solution of the crosslinkable acrylic polymer A (A-1) was 4900 mPa·s. The glass transition temperature (Tg) of this crosslinkable acrylic polymer A (A-1) was -21°C.

<Synthesis of Crosslinkable Acrylic Polymer A (A-2)>
A crosslinkable acrylic polymer A (A-2) having an acid component was prepared by solution polymerization in ethyl acetate. Specifically, butyl acrylate monomer (BA), methyl acrylate monomer (MA), methyl methacrylate (MMA), and acrylic acid (AA) were mixed in a mass ratio of 90:3:4:3 to initiate radical polymerization. AIBN (azobisisobutyronitrile) was dissolved in the solution as an agent. The solution was heated to 60° C. and subjected to random copolymerization to obtain a crosslinkable acrylic polymer A (A-2).

The solution viscosity of this 21% by mass solution of the crosslinkable acrylic polymer A (A-2) at 23° C. was 5400 mPa·s. The glass transition temperature (Tg) of this crosslinkable acrylic polymer A (A-2) was -30°C.

<Synthesis of Crosslinkable Acrylic Polymer A (A-3)>
A crosslinkable acrylic polymer A (A-3) having no acid component was prepared by solution polymerization in ethyl acetate. Specifically, 2-methoxyethyl acrylate monomer (MEA), 2-hydroxyethyl acrylate monomer (2HEA), methyl methacrylate (MMA), diethyl acrylamide (DEAA) and butyl acrylate (BA) were used in a mass ratio of 70:10:10. :5:5, and AIBN (azobisisobutyronitrile) was dissolved in the solution as a radical polymerization initiator. The solution was heated to 60° C. and subjected to random copolymerization to obtain a crosslinkable acrylic polymer A (A-3).

The solution viscosity of the 35 mass% solution of the crosslinkable acrylic polymer A (A-3) at 23° C. was 2000 mPa·s. The glass transition temperature (Tg) of this crosslinkable acrylic polymer A (A-3) was -30°C.

[Example 1]
With respect to 100 parts by mass of the crosslinkable acrylic polymer A (A-1), 0.05 parts by mass of an epoxy compound (Tetrad X manufactured by Mitsubishi Gas Chemical Co., Inc.) as a crosslinking agent B and ethylene as a polyfunctional monomer C. 12 parts by mass of oxide-modified diacrylate (Toagosei Co., Ltd., Aronix M211B, Tg=75° C.), and isobornyl acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd., IBXA, Tg=97° C.) as a monofunctional monomer D. 12 parts by mass, 0.7 parts by mass of 1-hydroxy-cyclohexyl-phenyl-ketone (IRGACURE184, manufactured by BASF Japan Ltd.) (abbreviation "Irg184") as a photopolymerization initiator E was added, and the solid content concentration became 24% by mass. Thus, ethyl acetate was added as a solvent to obtain a pressure-sensitive adhesive composition.

The above-mentioned pressure-sensitive adhesive composition was applied onto a first release sheet (heavy separator film, Teijin DuPont Films, release-treated polyethylene terephthalate film). The coating was performed using a doctor blade YD type manufactured by Yoshimitsu Seiki Co., Ltd. so that the thickness after drying was 25 μm. Then, it was dried at 100° C. for 3 minutes with a hot air dryer to remove the solvent and form a pressure-sensitive adhesive sheet having a semi-cured pressure-sensitive adhesive layer.

A second release sheet (light separator film, manufactured by Teijin DuPont Films Co., Ltd.), which has been subjected to a release treatment having a higher releasability than the first release sheet, is attached to one surface of this pressure-sensitive adhesive sheet, and the pressure-sensitive adhesive sheet with the release sheet is attached. An adhesive sheet of Example 1 was obtained.

[Example 2]
A pressure-sensitive adhesive composition and a pressure-sensitive adhesive sheet with a release sheet were obtained in the same manner as in Example 1 except that the addition amount of the polyfunctional monomer C was changed to 15 parts by mass in Example 1.

[Example 3]
A pressure-sensitive adhesive composition and a pressure-sensitive adhesive sheet with a release sheet were obtained in the same manner as in Example 1 except that the addition amount of the polyfunctional monomer C was changed to 20 parts by mass in Example 1.

[Example 4]
A pressure-sensitive adhesive composition and a pressure-sensitive adhesive sheet with a release sheet were obtained in the same manner as in Example 1 except that the crosslinkable acrylic polymer A in Example 1 was changed from (A-1) to (A-2).

[Comparative Example 1]
In the same manner as in Example 1 except that the addition amount of the polyfunctional monomer C was changed to 15 parts by mass and the monofunctional monomer D was not added in Example 1, the pressure-sensitive adhesive composition and An adhesive sheet with a release sheet was obtained.

[Comparative example 2]
With respect to 100 parts by mass of the crosslinkable acrylic polymer A (A-3), 0.5 parts by mass of a xylylene diisocyanate compound (Takenate D-110N manufactured by Mitsui Chemicals, Inc.) as a crosslinking agent B, and a polyfunctional monomer C As trimethylolpropane propylene oxide modified triacrylate (manufactured by Toagosei Co., Ltd., Aronix M321, Tg=50° C.), 15 parts by mass, and as a monofunctional monomer D, isobornyl acrylate (Osaka Organic Chemical Industry Co., Ltd., IBXA, 15 parts by mass of Tg=97° C., 0.7 parts by mass of 1-hydroxy-cyclohexyl-phenyl-ketone (IRGACURE184, manufactured by BASF Japan Ltd.) as a photopolymerization initiator E, and a solid content concentration of 40% by mass. A pressure-sensitive adhesive composition and a pressure-sensitive adhesive sheet with a release sheet were obtained in the same manner as in Example 1 except that ethyl acetate was added as a solvent to obtain a pressure-sensitive adhesive composition.

[Comparative Example 3]
In Comparative Example 2, the polyfunctional monomer C was changed to ethylene oxide-modified diacrylate (Toagosei Co., Ltd., Aronix M211B, Tg=75° C.), and the photopolymerization initiator E was not added. A pressure-sensitive adhesive composition and a pressure-sensitive adhesive sheet with a release sheet were obtained in the same manner as in Comparative Example 2.

[Measurement and evaluation]
<Acid value>
With a precision balance, the pressure-sensitive adhesive composition was precisely weighed in a 100 ml Erlenmeyer flask so that the solid content of the crosslinkable acrylic polymer A prepared above as a sample was about 2 g, and toluene/2-propanol/water= 10 ml of a mixed solvent of 5/5/0.5 (weight ratio) was added and dissolved. Next, 1 to 3 drops of p-naphtholbenzene solution as an indicator was added to this container, and the mixture was sufficiently stirred until the sample became uniform. This was titrated with a 0.1 N potassium hydroxide-2-propanol solution, and the end point of neutralization was when the light red color of the indicator continued for 30 seconds. The value obtained by using the following calculation formula (1) from the result was used as the acid value of the sample.

<Gel fraction>
The pressure-sensitive adhesive layer was cut to have a size of 100 mm×60 mm to prepare a semi-cured measurement sample.

The pressure-sensitive adhesive layer was cut to have a size of 100 mm×60 mm, and ultraviolet rays were irradiated from the side of the first release sheet, which is a heavy separator film, so that the integrated light amount was 3000 mJ/cm ^2, and the measurement sample after post-curing was obtained. It was made.

About 0.1 g of the adhesive sheet of each measurement sample was collected in a sample bottle, 30 ml of ethyl acetate was added, and the mixture was shaken for 24 hours. Then, the contents of this sample bottle were filtered with a 150-mesh stainless steel wire net, and the residue on the wire net was dried at 100° C. for 1 hour to measure the dry mass (g). The gel fraction was calculated from the obtained dry mass by the following formula 1.
Gel fraction (mass %)=(dry mass/adhesive sheet collection mass)×100...Equation 1

<Probe tack value>
The second release sheet, which is a light separator film of the pressure-sensitive adhesive sheet, was peeled off and attached to a PET film to prepare a measurement sample in a semi-cured state.

The second release sheet, which is a light separator film of another pressure-sensitive adhesive sheet, was peeled off and attached to a PET film. Next, ultraviolet rays were radiated from the side of the first release sheet, which is a heavy separator film, so that the integrated light amount was 3000 mJ/cm ^2, and a measurement sample after post-curing was prepared.

Each measurement sample was cut into 3 cm×3 cm, and measured with a probe tack tester under the following conditions. The measurement temperature was 23° C. and the relative humidity was 50%.
Measuring equipment: NS probe tack tester (Nichiban)
Probe diameter: 5mmφ
Probe base material: Stainless steel surface finish AA#400 Mirror surface weight by polishing: 19.6 g (made of brass)
Probe moving speed: 1.0 cm/sec Duel time: 1 sec

<Break elongation>
The breaking elongation was measured according to JIS K 7161-1. At that time, the tensile speed was 10 mm/min, and the measurement was performed in an environment of 23° C. and a relative humidity of 50%. As the measurement sample, a pressure-sensitive adhesive layer having a thickness of 25 μm, a width of 60 mm and a length of 200 mm was rolled in the length direction and processed into a columnar shape having a cross-sectional area of 5 mm ² and a height of 60 mm. The sample was set and pulled so that the distance between chucks was 30 mm, and the elongation at break of the sample was defined as the elongation at break. As a measuring instrument, an autograph AGS-X manufactured by Shimadzu Corporation was used.

<Workability>
First, the second release sheet, which is a light separator film for the pressure-sensitive adhesive layer, was peeled off and attached to a PET film having a thickness of 25 μm.

Next, the first release sheet, which is a heavy separator film, was peeled off and attached to a PC board. A sample having a composition of PET/adhesive layer/PC was autoclaved (40° C., 0.5 MPa, 30 min), and then irradiated with ultraviolet rays from the PET film side so that the accumulated light amount was 3000 mJ/cm ^2, and a test sample Got Next, the end portion of the test sample was cut using a guillotine cutting machine, and the cut end portion was rubbed by peeling the PET film from the PC plate side by hand. The workability was evaluated by measuring the peeling distance at that time. The evaluation criteria are as follows, A and B are acceptable (allowable range), and C is unacceptable.
A: Peeling distance is less than 0.05 mm B: Peeling distance is 0.05 mm or more and less than 0.1 mm C: Peeling distance is 0.1 mm or more

<Constant load peel distance>
The light release separator which is the second release sheet was peeled off, and instead of the peeled off separator, a triacetyl cellulose film (Fuji Film Co., Fujitac TD60UL thickness 60 μm) was laminated using a hand roller to prepare a laminated film. .. This laminated film was cut into a size having a width of 25 mm and a length of 100 mm, and the first release sheet was peeled off. Then, the exposed area of 25 mm in width and 100 mm in length of the adhesive surface is covered with a region of 25 mm in width and 75 mm in length on the hard coat surface side of the adherend (polycarbonate plate with hard coat layer: Mitsubishi Gas Chemical Co., Inc., Iupilon MR58 thickness 1 mm) Was attached using a 2 kg pressure roller. In this state, it was kept in an autoclave under the conditions of 40° C. and 5 atm for 30 minutes and brought into close contact with the PC plate, and then irradiated with ultraviolet rays from the side of the triacetyl cellulose film so that the integrated light amount was 3000 mJ/cm ² , A test piece was prepared.

After this test piece was left for 24 hours in an environment of i) 85° C., relative humidity of 85%, and ii) 85° C., relative humidity of less than 10%, respectively, i) 85° C., relative humidity of 85%, and ii) Under an environment of 85° C. and a relative humidity of less than 10%, 100 g of weight 34 is hung at the end of the non-bonding region (width 25 mm, length 25 mm) of the laminated film as shown in FIG. A load of 100 g was applied in a direction of 90° with respect to the plane of the body 32, and the body was left standing for another 5 minutes. During that time, the length L (constant load peeling distance) of the portion where the laminated film was peeled off was measured. The evaluation criteria are as follows, A and B are acceptable (allowable range), and C is unacceptable.
A: Peeling is not confirmed, or peeling of less than 1 mm is observed B: Peeling of 1 mm or more and 50 mm or less is observed C: Peeling of more than 50 mm is observed

<Durability>
The second release sheet, which is a light separator film for the pressure-sensitive adhesive layer, was peeled off and laminated on a triacetylcellulose film (Fujitac TD60UL, thickness 60 μm, manufactured by Fuji Film Co., Ltd.).

Next, the first release sheet, which is a heavy separator film, was peeled off and attached to a PC plate (polycarbonate plate with a hard coat layer: Mitsubishi Gas Chemical Co., Inc., Iupilon MR58 thickness 1 mm). A sample having a structure of triacetyl cellulose film/adhesive layer/PC is autoclaved (40° C., 0.5 MPa, 30 min), and then the integrated amount of ultraviolet rays from the side of the triacetyl cellulose film becomes 3000 mJ/cm ^2. Irradiation was performed to obtain a test sample having a size of 100 mm×200 mm. Then, the test sample is allowed to stand for 240 hours in an environment of i) 85° C. and relative humidity of 85% and ii) environment of 85° C. and less than 10% of relative humidity, respectively. After that, the test sample was observed to see if any floating or peeling occurred. The determination of the condition i) indicates high temperature and high humidity durability, and the determination of the condition ii) indicates high temperature durability. The evaluation criteria are as follows, a is a pass (allowable range), and b is a fail.
a: 1.0 mm or more floating and peeling is not observed b: 1.0 mm or more floating and/or peeling is observed

From Table 1 above, it was found that the pressure-sensitive adhesive sheets of the examples can exhibit excellent substrate adhesion and durability not only under high temperature conditions but also under high temperature and high humidity conditions. In addition, the pressure-sensitive adhesive sheets of Examples had no stickiness on the end faces and had good workability. On the other hand, the pressure-sensitive adhesive sheets of Comparative Examples were inferior in substrate adhesion and durability or workability under high temperature conditions and high temperature and high humidity conditions.

DESCRIPTION OF SYMBOLS 1 Adhesive sheet 11 Adhesive layer 12a Transparent base material or release sheet 12b Release sheet 20 Laminated body 21 Adhesive sheet 22 Base material 24 Optical member 27a, 27b, 27c, 27d Step part 30 Triacetyl cellulose film 32 Adherent 34 Weight L Constant load separation distance

Claims

A pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer in which the pressure-sensitive adhesive composition is in a semi-cured state,
The pressure-sensitive adhesive composition comprises a cross-linkable acrylic copolymer A having an acid component, a cross-linking agent B, a polyfunctional monomer C having two or more reactive double bonds in the molecule, and a reactive double bond in the molecule. Containing a monofunctional monomer D having one bond and a photopolymerization initiator E,
The glass transition temperature (Tg) of the crosslinkable acrylic copolymer A is −40° C. or higher,
The pressure-sensitive adhesive layer has a post-curing property,
A pressure-sensitive adhesive sheet that satisfies the following physical properties (1) and (2) when the pressure-sensitive adhesive layer is post-cured by irradiating the pressure-sensitive adhesive layer with active energy rays so that the integrated light amount becomes 3000 mJ/cm 2 .
Physical properties (1): breaking elongation in a tensile test measurement at a tensile speed of 10 mm/min is less than 500%;
Physical Properties (2): Each constant load peeling distance at i) 85° C., relative humidity 85%, and ii) at 85° C., relative humidity less than 10% is 50 mm or less measured under the following measurement conditions:
(Measurement condition)
A region having a width of 25 mm and a length of 75 mm on the adhesive surface of the adhesive layer having a width of 25 mm and a length of 100 mm is attached to an adherend and post-cured. i) 85° C., 85% relative humidity, and ii) 85° C., less than 10% relative humidity In each environment, the adherend is fixed horizontally so that the non-bonded region of the adhesive layer hangs downward. .. A load of 100 g is applied to the end portion in the length direction of the non-bonded region of the pressure-sensitive adhesive layer for 5 minutes, and the distance at which the bonded region of the pressure-sensitive adhesive layer is separated from the adherend is i) 85° C. and relative humidity of 85%. , And ii) Measured as each constant load peel distance at 85° C. and relative humidity of less than 10%.
The pressure-sensitive adhesive sheet according to claim 1, wherein the content of the monofunctional monomer D is 10 to 40 parts by mass with respect to 100 parts by mass of the crosslinkable acrylic copolymer A.
The pressure-sensitive adhesive sheet according to claim 1 or 2, wherein the content of the polyfunctional monomer C is 10 to 40 parts by mass with respect to 100 parts by mass of the crosslinkable acrylic copolymer A.
The pressure-sensitive adhesive sheet according to any one of claims 1 to 3, wherein the crosslinkable acrylic copolymer A has an acid value of 1 mgKOH/g or more.
The pressure-sensitive adhesive sheet according to any one of claims 1 to 4, wherein the difference between the gel fraction in the semi-cured state of the pressure-sensitive adhesive layer and the gel fraction after post-curing is 15% or more.
An adhesive sheet with a release sheet, comprising a pair of release sheets having different release forces on both sides of the adhesive sheet according to any one of claims 1 to 5.
A laminate comprising the pressure-sensitive adhesive sheet according to any one of claims 1 to 5 and an adherend provided on at least one surface side of the pressure-sensitive adhesive sheet, wherein the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet is an active energy ray. A laminate which has been post-cured by irradiation with.
The step 1 of laminating an adherend on at least one surface side of the pressure-sensitive adhesive sheet according to any one of claims 1 to 5, and the pressure-sensitive adhesive layer by irradiating the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet with active energy rays. The manufacturing method of a laminated body which has the process 2 post-curing in order.