JP2021143253A - Adhesive sheet, adhesive sheet with release sheet and laminate - Google Patents

Abstract

To provide an adhesive sheet that exhibits excellent outgas resistance and curling resistance after post-curing, and also has excellent designability.SOLUTION: An adhesive sheet has an adhesive layer including an adhesive composition in a semi-cured state. The adhesive composition contains a crosslinkable (meth)acryl copolymer, a crosslinker, a first polyrotaxane, a second polyrotaxane, a monomer having an alkylene glycol group in a molecule and having two (meth)acryloyl groups, a polymerization initiator and a colorant.SELECTED DRAWING: Figure 1

Description

The present invention relates to an adhesive sheet, an adhesive sheet with a release sheet, and a laminate.

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

It is known that there are several polymerization methods as described below as a polymerization method of the pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive sheet. Specifically, there are methods such as polymerization by heat, polymerization by active energy rays, polymerization by heat (or active energy rays), and then polymerization by active energy rays (or heat) in two stages.

The pressure-sensitive adhesive sheet formed by two-stage polymerization, in which polymerization is carried out by heat (or active energy rays) and then polymerization by active energy rays (or heat), is a pressure-sensitive adhesive having both thermosetting properties and active energy ray-curable properties. It is formed from a composition (hereinafter, may be referred to as "dual curable pressure-sensitive adhesive composition"). For example, the pressure-sensitive adhesive composition is thermoset before being bonded to the adherend, temporarily adhered to the adherend, and then further irradiated with active energy rays to completely cure the pressure-sensitive adhesive composition ( It is called post-curing or after-cure). As a result, the pressure-sensitive adhesive layer is firmly adhered to the adherend.

Patent Document 1 includes 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 a lauryl acrylate (b1). The monomer (B), the cross-linking agent (C) that reacts with the base polymer (A) by heat, and the polymerization initiator (D) that initiates the polymerization reaction of the monomer (B) by irradiation with active energy rays. , A pressure-sensitive adhesive sheet containing a pressure-sensitive adhesive layer obtained by semi-curing a pressure-sensitive adhesive composition containing the solvent (E) by heating is described.
Further, Patent Document 2 describes a pressure-sensitive adhesive sheet comprising a (meth) acrylic acid ester copolymer, a heat-crosslinking agent, an active energy ray-curable component, and an active energy ray-curable pressure-sensitive adhesive containing a polyrotaxane compound. Is disclosed. Here, the polyrotaxane compound is incorporated into the crosslinked structure of the base polymer in a semi-cured state.

Patent Document 3 discloses a black foil-like pressure-sensitive adhesive containing a pressure-sensitive adhesive component, a black pigment, and a styrene maleic acid resin. However, the pressure-sensitive adhesive of Patent Document 3 has already been crosslinked by a cross-linking agent and does not have post-curing property.

Japanese Unexamined Patent Publication No. 2016-084391 JP-A-2018-44134 Japanese Unexamined Patent Publication No. 2013-32430

When the pressure-sensitive adhesive sheet is attached to, for example, a resin plate that easily generates outgas, air bubbles may be generated at the interface between the pressure-sensitive adhesive sheet and the resin plate or in the pressure-sensitive adhesive sheet. Further, in recent years, an optical member to which an adhesive sheet is attached may be used in a harsh environment such as a high temperature or high humidity environment, and in such an environment, the optical member has dimensions as the heat or humidity changes. May make a difference. Depending on the material of the optical member, the degree of susceptibility to heat is different. Therefore, when other types of optical members are bonded together, there is a difference in dimensions between the pair of optical members, and the adhesive sheet is accordingly. It was a problem because it could curl.

Further, as described above, a black adhesive sheet obtained by coloring an adhesive is known, but it is not supposed to be used for bonding with a display surface or as a dual curable adhesive sheet, and is adhesive. The examination of the design of the sheet was insufficient.

Therefore, in order to solve the problems of the prior art, the present inventors have a dual-curing adhesive sheet, which is excellent in outgas resistance and curl resistance after post-curing, and is also excellent in design. We proceeded with the study for the purpose of providing an adhesive sheet.

As a result of diligent studies to solve the above problems, the present inventors have added a crosslinkable (meth) acrylic copolymer to the pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive sheet having the pressure-sensitive adhesive layer in a semi-cured state. , Cross-linking agent, first polyrotaxane having a predetermined structure, second polyrotaxane having a predetermined structure, a monomer having an alkylene glycol group in the molecule and two (meth) acryloyl groups, a polymerization initiator and a coloring agent. By blending the agent, it is possible to incorporate the polyrotaxane structure in both the base polymer and the post-curing component, whereby the adhesive layer after post-curing can exhibit excellent outgas resistance and curl resistance. I found that. Also. The present inventors have found that such an adhesive layer also has high transparency, and have completed the present invention.
Specifically, the present invention has the following configuration.

[1] An adhesive sheet having an adhesive layer in which the adhesive composition is in a semi-cured state.
The pressure-sensitive adhesive composition is a crosslinkable (meth) acrylic copolymer, a crosslinker, a first polyrotaxane, a second polyrotaxane, and a monomer having an alkylene glycol group in the molecule and two (meth) acryloyl groups. , Contains polymerization initiator and colorant,
The first polyrotaxane has a linear portion and a cyclic portion that is included in a state of penetrating a part of the linear portion, and the molecule constituting the cyclic portion has a hydroxy group.
The second polyrotaxane is an adhesive sheet having a linear portion and an annular portion that is included in a state of penetrating a part of the linear portion, and the molecule constituting the cyclic portion has a vinyl group.
[2] The adhesive sheet according to [1], which has a total light transmittance of 5 to 90%.
[3] The pressure-sensitive adhesive sheet according to [1] or [2], wherein the colorant is at least one selected from metal oxides and carbon black.
[4] The pressure-sensitive adhesive sheet according to any one of [1] to [3], wherein the colorant is a metal oxide.
[5] The pressure-sensitive adhesive sheet according to any one of [1] to [4], wherein the average particle size of the colorant is 0.01 μm or more and less than 5 μm.
[6] The content of the first polyrotaxane is 0.1 to 3 parts by mass with respect to 100 parts by mass of the crosslinkable (meth) acrylic copolymer, according to any one of [1] to [5]. Adhesive sheet.
[7] The content of the second polyrotaxane is 0.1 to 3 parts by mass with respect to 100 parts by mass of the crosslinkable (meth) acrylic copolymer, according to any one of [1] to [6]. Adhesive sheet.
[8] The pressure-sensitive adhesive sheet according to any one of [1] to [7], wherein the content of the monomer is 1 to 20 parts by mass with respect to 100 parts by mass of the crosslinkable (meth) acrylic copolymer.
[9] The adhesion according to any one of [1] to [8], wherein the polymerization initiator is a photopolymerization initiator having an absorbance of 0.2 or more at a wavelength of 380 nm in an acetonitrile solution having a concentration of 0.1% by mass. Sheet.
[10] The pressure-sensitive adhesive sheet according to any one of [1] to [9], wherein the cross-linking agent is at least one selected from a 2-4-functional isocyanate-based cross-linking agent and a 2-4-functional epoxy-based cross-linking agent. ..
[11] For bonding the first member,
The pressure-sensitive adhesive sheet according to any one of [1] to [10], wherein the first member is at least one selected from a resin plate, a resin sheet, and a resin film.
[12] For bonding the second member,
The adhesive sheet according to any one of [1] to [11], wherein the second member is at least one selected from a glass plate, a resin plate, a resin sheet, and a resin film.
[13] The pressure-sensitive adhesive sheet according to [11] or [12], wherein the resin plate, the resin sheet and the resin film contain at least one selected from a polycarbonate resin and a (meth) acrylic resin.
[14] An adhesive sheet with a release sheet, comprising a pair of release sheets having different peeling forces on both surfaces of the adhesive sheet according to any one of [1] to [13].
[15] The pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet according to any one of [1] to [13] is irradiated with active energy rays and post-cured, and then the pressure-sensitive adhesive layer and the post-cured pressure-sensitive adhesive layer. A laminate having a first member on one surface side and a second member on the other surface side of the post-cured pressure-sensitive adhesive layer.

According to the present invention, it is possible to obtain an adhesive sheet that exhibits excellent outgas resistance and curl resistance after post-curing, and also has excellent design.

FIG. 1 is a schematic view showing a cross section of a release sheet or an adhesive sheet having a base material. FIG. 2 is a schematic diagram illustrating the structure of polyrotaxane.

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

In addition, in this specification, "(meth) acrylic" represents both acrylic and / or methacryl. Further, in the present specification, "monomer" and "monomer" are synonymous, and "polymer" and "polymer" are synonymous.

<Adhesive sheet>
The pressure-sensitive adhesive sheet of the present invention has a pressure-sensitive adhesive layer in which the pressure-sensitive adhesive composition is in a semi-cured state. Here, the pressure-sensitive adhesive composition has a crosslinkable (meth) acrylic copolymer, a crosslinker, a first polyrotaxane, a second polyrotaxane, an alkylene glycol group in the molecule, and two (meth) acryloyl groups. Contains the monomer, polymerization initiator and colorant to have. The first polyrotaxane has a linear portion and a cyclic portion that is included in a state of penetrating a part of the linear portion, and the molecule constituting the cyclic portion has a hydroxy group. Further, the second polyrotaxane has a linear portion and a cyclic portion that is included in a state of penetrating a part of the linear portion, and the molecule constituting the cyclic portion has a vinyl group.

With the above configuration, in the pressure-sensitive adhesive sheet of the present invention, the first polyrotaxane was incorporated into the crosslinked structure of the crosslinkable (meth) acrylic copolymer during thermosetting, and the second polyrotaxane was formed by post-curing during post-hardening. Since it is incorporated into the polymer, a pressure-sensitive adhesive layer having both hardness and stress relaxation properties is formed. Therefore, the pressure-sensitive adhesive sheet of the present invention can exhibit excellent outgas resistance and curl resistance after post-curing. On the other hand, the pressure-sensitive adhesive sheet of the present invention has an adhesive layer in a semi-cured state before post-curing, and therefore has excellent flexibility in the semi-cured state. Excellent adhesion to the adherend, for example, even when the adherend has a curved surface or a stepped portion, it follows the shape of the adherend and exhibits excellent adhesion. Then, since post-curing is performed in such a state, the pressure-sensitive adhesive layer can be firmly adhered to the adherend. As described above, the adhesive sheet of the present invention exhibits excellent outgas resistance and curl resistance while firmly adhering to the adherend during post-curing.

Further, by having the above-mentioned structure, the adhesive sheet of the present invention can enhance its design when it is attached to a display or the like displaying a black screen. Specifically, when the adhesive sheet of the present invention is attached to a display displaying a black screen, the degree of black color development (preferability of the degree of blackness) of the display can be increased, so that the display and the display are provided. The design of the display device can be enhanced. Further, even if the display is in a state where the black screen is not displayed, the degree of blackness of the display is increased by attaching the adhesive sheet, so that the sense of unity with the surroundings is emphasized and the design is enhanced.

Further, the adhesive sheet of the present invention has high visibility, and even when the adhesive sheet is attached to the visible surface side of the display, for example, the characters displayed on the display are prevented from blurring. As described above, the adhesive sheet for bonding optical members of the present invention has succeeded in increasing the degree of black color development of the display or the like but not deteriorating the visibility of the display or the like.

In the present specification, the outgas resistance of the pressure-sensitive adhesive sheet after post-curing is such that the integrated light amount becomes 3000 mJ / cm ^{2 after the adherend is attached to both sides of the pressure-sensitive adhesive layer to prepare a laminated body.} It can be evaluated by irradiating with ultraviolet rays, placing it in an environment of 85 ° C. and 85% relative humidity, and visually confirming each of the laminated bodies after 2 hours and 100 hours. Specifically, it is preferable that no bubbles, floats and peels are observed in the laminate after 2 hours, and more preferably no bubbles, floats and peels are observed in the laminate after 2 hours and 100 hours.

Further, in the present specification, the curl resistance of the pressure-sensitive adhesive sheet after post-curing is such that the adherend is attached to both sides of the pressure-sensitive adhesive layer to prepare a laminate, and then the laminate is heated to 105 ° C. (relative humidity 20). It can be evaluated by treating it in an oven (% or less) for 24 hours, taking it out, and allowing it to stand on a horizontal surface within 5 minutes. At this time, the laminated body is allowed to stand so that the convex surface faces downward, and the heights of the four corners of the sample from the waterside surface are measured to calculate the average value. When the average value is less than 5 mm, it can be determined that the curl resistance is good.

Polyrotaxane has a drawback that it is difficult to be compatible with other high molecular weight materials, and when it is added to a conventional pressure-sensitive adhesive composition, transparency is impaired even in a small amount and it cannot be used for bonding optical system members. However, by using a monomer having an alkylene glycol group and two (meth) acryloyl groups in the molecule, the pressure-sensitive adhesive sheet of the present invention can exhibit relatively high transparency.

The total light transmittance of the pressure-sensitive adhesive sheet is preferably 5% or more, more preferably 10% or more, and further preferably 15% or more. The total light transmittance of the pressure-sensitive adhesive sheet is preferably 90% or less, more preferably 80% or less, and further preferably 75% or less. By setting the total light transmittance of the adhesive sheet within the above range, it is possible to increase the degree of black color development of the display or the like.
The total light transmittance is the total light transmittance of the pressure-sensitive adhesive sheet in the semi-cured state. The total light transmittance of the adhesive sheet is measured according to JIS K 7150. For the measurement, for example, an integrating sphere type light transmittance measuring device (manufactured by Nippon Denshoku Kogyo Co., Ltd., NDH-5000) can be used, the measurement is performed three times, and the average value is taken as the total light transmittance of the adhesive sheet. do.

The haze of the pressure-sensitive adhesive sheet is preferably 10% or less, more preferably 5% or less, and even more preferably 3% or less. By setting the haze of the adhesive sheet within the above range, visibility can be maintained while increasing the degree of black color development of the display or the like.

In the present invention, the pressure-sensitive adhesive composition is blended with two types of polyrotaxanes having different structures, and a monomer having an alkylene glycol group and two (meth) acryloyl groups in the molecule is used in combination. Since the polyrotaxane structure is incorporated into both the crosslinkable (meth) acrylic copolymer, which is the base polymer, and the post-curing component, the stress when heated while increasing the hardness and transparency of the adhesive layer after post-curing. The relaxation property can be enhanced. Thereby, the curl resistance of the pressure-sensitive adhesive layer after post-curing can be enhanced. Further, by using such a pressure-sensitive adhesive composition, the pressure-sensitive adhesive layer after post-curing can exhibit excellent outgas resistance. Further, by blending a colorant in the pressure-sensitive adhesive composition, it is possible to enhance the design when the pressure-sensitive adhesive sheet is attached to an adherend such as a display.

<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 of only the pressure-sensitive adhesive layer. Further, the pressure-sensitive adhesive sheet may be a single-sided pressure-sensitive adhesive sheet having a base material (preferably a transparent base material) on one side, or a double-sided pressure-sensitive adhesive sheet. The double-sided adhesive sheet includes a single-layer adhesive sheet composed of an adhesive layer, a multi-layer adhesive sheet in which a plurality of adhesive layers are laminated, and a multi-layer adhesive in which another adhesive layer is laminated between the adhesive layers. A multi-layered pressure-sensitive adhesive sheet in which a support is laminated between a sheet, a pressure-sensitive adhesive layer and a pressure-sensitive adhesive layer, and a multi-layered pressure-sensitive adhesive sheet in which a pressure-sensitive adhesive layer is laminated on one side of the support and another pressure-sensitive adhesive layer is laminated on the other side. Can be mentioned. When the double-sided 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 can be used as in the case of the transparent substrate. Since such a double-sided pressure-sensitive adhesive sheet is also excellent in transparency of the pressure-sensitive adhesive sheet as a whole, it can be suitably used for bonding optical members to each other.

The pressure-sensitive adhesive sheet of the present invention is preferably a double-sided pressure-sensitive adhesive sheet. Further, the present invention may relate to an adhesive sheet with a release sheet provided with release sheets on both surfaces of the adhesive sheet. When the release sheets are provided on both surfaces of the pressure-sensitive adhesive sheet of the present invention, the pressure-sensitive adhesive sheet 10 with the release sheet may have the release sheets 12a and 12b on both surfaces of the pressure-sensitive adhesive layer 11 as shown in FIG. preferable.

The release sheet is a removable laminated sheet having a release sheet base material and a release agent layer provided on one side of the release sheet base material, or a polyolefin film such as a polyethylene film or polypropylene film as a low-polarity base material. Can be mentioned.
Papers and polymer films are used as the base material for the release sheet in the releaseable laminated sheet. As the release agent constituting the release agent layer, for example, a general-purpose addition-type or condensation-type silicone-based 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, and X62-2600 manufactured by Shin-Etsu Chemical Co., Ltd. Can be mentioned. Further, it contains a silicone resin which is an organic silicon compound having an SiO ₂ units and _{(CH 3) 3 SiO 1/2} units or _{CH 2 = CH (CH 3)} SiO 1/2 units in the silicone-based release agent preferable. Specific examples of the silicone resin include BY24-843, SD-7292, SHR-1404, etc. manufactured by Toray Dow Corning Silicone Co., Ltd., KS-3800, X92-183, etc. manufactured by Shin-Etsu Chemical Co., Ltd.
A commercially available product may be used as the peelable laminated sheet. Examples include a heavy separator film, which is a release-treated polyethylene terephthalate film manufactured by Teijin DuPont Film Co., Ltd., and a light separator film, which is a release-treated polyethylene terephthalate film manufactured by Teijin DuPont Film Co., Ltd. can.

The pressure-sensitive adhesive sheet with a release sheet preferably has a pair of release sheets having different peeling forces on both surfaces of the pressure-sensitive adhesive sheet. That is, it is preferable that the release sheet has different peelability between the release sheet 12a and the release sheet 12b in order to facilitate the release. When the peelability from one side and the peelability from the other side are different, it becomes easy to peel off only the release sheet having the higher peelability first. In that case, the peelability of the release sheet 12a and the release sheet 12b may be adjusted according to the bonding method and the bonding order.

Further, the present invention may relate to a pressure-sensitive adhesive sheet with a transparent film having a transparent film on at least one surface of the pressure-sensitive adhesive sheet. In this case, the transparent film is preferably at least one selected from a polyethylene terephthalate film, an acrylic film, a polycarbonate film, a triacetyl cellulose film and a cycloolefin polymer film. The adhesive sheet with a transparent film may be a sheet in which a transparent film / 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 in which the pressure-sensitive adhesive composition is in a semi-cured state, and the pressure-sensitive adhesive layer has post-curing property. The pressure-sensitive adhesive sheet may be made of a pressure-sensitive adhesive layer.

In the present specification, when the gel fraction of the pressure-sensitive adhesive layer is increased by 10% by mass or more by irradiating or heating with active energy rays under the following conditions, the pressure-sensitive adhesive layer before irradiation or heating is in a semi-cured state. Suppose there is. In this case, when the pressure-sensitive adhesive layer is post-cured by irradiating with active energy rays, the optical transparent PET separators are attached to both sides of the pressure-sensitive adhesive layer, and the active energy rays (high-pressure mercury lamp or high-pressure mercury lamp or) are applied from the optical transparent PET separator side. The metal halide lamp) is irradiated so that the integrated light amount is 3000 mJ / cm ^2. When the pressure-sensitive adhesive layer is post-cured by heating, heat treatment is performed in an oven at 100 ° C. for 1 hour with separator films (release sheets) attached to both surfaces of the pressure-sensitive adhesive layer.
Above all, the gel fraction of the pressure-sensitive adhesive layer in the semi-cured state is preferably 10% by mass or more and less than 70% by mass, and more preferably 20% by mass or more and less than 60% by mass. The gel fraction of the pressure-sensitive adhesive layer after post-curing is preferably 60 to 100% by mass, more preferably 70 to 100% by mass.

The gel fraction of the pressure-sensitive adhesive layer is a value measured by the following method. First, about 0.1 g of an 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 through a 150 mesh stainless steel wire mesh, and the residue on the wire mesh 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 sheet) x 100 ... Equation 1

In the present specification, the "semi-cured state" is preferably a state after thermosetting. Then, it is preferable to "post-cure" by irradiating with active energy rays after that. That is, the "semi-cured state" is preferably a state after thermosetting and is a soft pressure-sensitive adhesive layer before irradiation with active energy rays. The "post-curing" is preferably a step of completely curing the pressure-sensitive adhesive layer with heat or active energy rays, and more preferably a step of completely curing the pressure-sensitive adhesive layer 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.

The thickness of the pressure-sensitive adhesive layer can be appropriately set depending on the intended use, and is not particularly limited, but is preferably 5 to 1000 μm, more preferably 8 to 500 μm, and particularly preferably 10 to 300 μm. By setting the thickness of the pressure-sensitive adhesive layer within the above range, it is possible to suppress the stickiness and stickiness of the pressure-sensitive adhesive, and thus the workability can be improved. Further, by setting the thickness of the pressure-sensitive adhesive layer within the above range, the production of a double-sided pressure-sensitive adhesive sheet becomes easy.

The adhesive force against glass with a peeling speed of 300 mm / min measured by a method according to JIS Z 0237 of the pressure-sensitive adhesive layer is preferably 10 to 50 N / 25 mm in both the semi-cured state and after post-curing, and is preferably 15 to 45 N /. It is more preferably 25 mm. By setting the adhesive force of the pressure-sensitive adhesive layer against the glass within the above range, unintentional peeling of the pressure-sensitive adhesive layer can be suppressed, while re-peeling can be easily performed when the pressure-sensitive adhesive layer is erroneously bonded.

<Adhesive composition>
The above-mentioned pressure-sensitive adhesive layer is a semi-cured state of 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 crosslinkable (meth) acrylic copolymer, a crosslinker, a first polyrotaxane, a second polyrotaxane, and a monomer having an alkylene glycol group in the molecule and two (meth) acryloyl groups. , A polymerization initiator and a colorant.

(Crosslinkable (meth) acrylic copolymer)
The crosslinkable (meth) acrylic copolymer is not particularly limited as long as it has an acrylic monomer unit, and for example, a non-crosslinkable (meth) acrylic acid ester unit (a1) and a crosslinkable functional group can be used. It may contain the having acrylic monomer unit (a2). The crosslinkable (meth) acrylic copolymer preferably has transparency to the extent that it does not reduce the visibility of the display device. In the present specification and claims, the "unit" is a repeating unit (monomer unit) constituting the polymer.

The non-crosslinkable (meth) acrylic acid ester unit (a1) is a repeating unit derived from the (meth) acrylic acid alkyl ester. Examples of the (meth) acrylic acid alkyl ester include methyl (meth) acrylic acid, ethyl (meth) acrylic acid, propyl (meth) acrylic acid, isopropyl (meth) acrylic acid, n-butyl (meth) acrylic acid, and (meth). Isobutyl acrylate, t-butyl (meth) acrylate, n-pentyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, ( Isooctyl 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. One of these may be used alone, or two or more thereof may be used in combination.
Among the above (meth) acrylic acid alkyl esters, at least one selected from methyl (meth) acrylate, n-butyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate is selected because of its high adhesiveness. preferable.

In the present invention, the crosslinkable functional group of the crosslinkable (meth) acrylic copolymer is one or more selected from a carboxy group, a hydroxy group, an amino group, an amide group, a glycidyl group and an isocyanate group. It is preferable, and more preferably one or more selected from a carboxy group, a hydroxy group, an amino group and a glycidyl group.
The acrylic monomer unit (a2) having a crosslinkable functional group is preferably a carboxy group-containing monomer unit, a hydroxy group-containing monomer unit, an amino group-containing monomer unit, or a glycidyl group-containing monomer unit.
Examples of the carboxy group-containing monomer unit include acrylic acid and methacrylic acid.
The hydroxy group-containing monomer unit is a repeating unit derived from the hydroxy group-containing monomer. Examples of the hydroxy group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 3-chloro-2-hydroxypropyl (meth) acrylate. , 4-Hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, polyalkylene glycol mono (meth) acrylate and the like.
Examples of the amino group-containing monomer unit include repeating units derived from amino group-containing monomers such as (meth) acrylamide and allylamine.
Examples of the glycidyl group-containing monomer unit include repeating units derived from a glycidyl group-containing monomer such as glycidyl (meth) acrylate.

The content of the acrylic monomer unit (a2) having a crosslinkable functional group in the crosslinkable (meth) acrylic copolymer is preferably 0.5 to 50% by mass, preferably 1.0 to 40% by mass. Is more preferable. When the content of the acrylic monomer unit (a2) having a crosslinkable functional group is at least the lower limit of the above range, it has sufficient crosslinkability necessary for maintaining the semi-cured state, and is in the above range. If it is below the upper limit of, it is easy to maintain the required adhesiveness.

When the acrylic monomer unit having a crosslinkable functional group in the crosslinkable (meth) acrylic copolymer is a unit derived from a hydroxy group-containing (meth) acrylate, a unit derived from the hydroxy group-containing (meth) acrylate. The content is preferably 5% by mass or more, and more preferably 10% by mass or more, based on the total mass of the crosslinkable (meth) acrylic copolymer. The content of the unit derived from the hydroxy group-containing (meth) acrylate is preferably 50% by mass or less, preferably 40% by mass or less, based on the total mass of the crosslinkable (meth) acrylic copolymer. Is more preferable. By setting the content of the unit derived from the hydroxy group-containing (meth) acrylate within the above range, the adhesion to the adherend can be further enhanced.

In the crosslinkable (meth) acrylic copolymer, the content of the carboxy group-containing monomer unit may be 1% by mass or less with respect to the total mass of the crosslinkable (meth) acrylic copolymer. Preferably, it may be 0% by mass. Examples of the carboxy group-containing monomer unit include acrylic acid and methacrylic acid.

<Nitrogen-containing monomer>
The crosslinkable (meth) acrylic copolymer may further contain units derived from nitrogen-containing monomers. The nitrogen-containing monomer is a monomer containing a nitrogen element in one molecule. Examples of the nitrogen-containing monomer include dimethylacrylamide, diethylacrylamide, acryloylmorpholin, hydroxyethylacrylamide, methylolacrylamide, methoxymethylacrylamide, ethoxymethylacrylamide, dimethylaminoethylacrylamide, N-vinylcaprolactam, and N-vinyl-2-. Examples thereof include pyrrolidone, dimethylaminoethyl (meth) acrylate, and N-vinylformamide. Among them, the nitrogen-containing monomer is preferably at least one selected from an acrylamide derivative, an amino group-containing monomer and a nitrogen-containing heterocyclic ring-containing monomer, and more preferably an acrylamide derivative. The acrylamide derivative is more preferably at least one selected from dimethylacrylamide, diethylacrylamide and acryloylmorpholine, and particularly preferably dimethylacrylamide. When the crosslinkable (meth) acrylic copolymer contains a unit derived from the nitrogen-containing monomer as described above, the semi-cured pressure-sensitive adhesive layer is easily adhered to the substrate, while being easily adhered to the substrate. The adhesive layer after post-curing has a high hardness, and the outgas resistance can be further enhanced.

When the crosslinkable (meth) acrylic copolymer contains units derived from the nitrogen-containing monomer, the content of the units derived from the nitrogen-containing monomer is the total mass of the crosslinkable (meth) acrylic copolymer. On the other hand, it is preferably 1% by mass or more, and more preferably 3% by mass or more. The content of the unit derived from the nitrogen-containing monomer is preferably 20% by mass or less with respect to the total mass of the crosslinkable (meth) acrylic copolymer.

The crosslinkable (meth) acrylic copolymer may have other monomeric units, if desired. The other monomer may be a monomer copolymerizable 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 (meth) acrylic copolymer is preferably 20% by mass or less, and more preferably 15% by mass or less.

<Weight average molecular weight of crosslinkable (meth) acrylic copolymer>
The weight average molecular weight of the crosslinkable (meth) acrylic copolymer is preferably 100,000 to 2 million, more preferably 200,000 to 1.5 million. When the weight average molecular weight is within the above range, it is easy to maintain the semi-cured state of the pressure-sensitive adhesive sheet, and it is easy to obtain the hardness after post-curing, and the processability is excellent. The weight average molecular weight of the crosslinkable (meth) acrylic copolymer is a value before cross-linking with a cross-linking agent. The weight average molecular weight is a value measured by size exclusion chromatography (SEC) and determined based on polystyrene. As the crosslinkable (meth) acrylic copolymer, a commercially available one may be used, or one synthesized by a known method may be used.

(Crosslinking agent)
The pressure-sensitive adhesive composition contains a cross-linking agent. The cross-linking agent can be appropriately selected in consideration of the reactivity of the cross-linking (meth) acrylic copolymer with the cross-linking functional group. For example, it can be selected from known cross-linking agents such as isocyanate compounds, epoxy compounds, oxazoline compounds, aziridine compounds, metal chelate compounds and butylated melamine compounds. Among these, it is preferable to use an isocyanate compound or an epoxy compound because the hydroxy group-containing (meth) acrylate can be easily crosslinked. That is, the cross-linking agent is preferably at least one selected from a 2- to 4-functional isocyanate-based cross-linking agent and a 2- to 4-functional epoxy-based cross-linking agent.

Examples of the isocyanate compound include tolylene diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate and the like. Examples of commercially available products include tolylene diisocyanate compounds (manufactured by Nippon Polyurethane Industry Co., Ltd., Coronate L), xylylene diisocyanate compounds (manufactured by Mitsui Chemicals, Inc., Takenate D-110N) and the like. Examples of the epoxy compound include TETRAD-C (manufactured by Mitsubishi Gas Chemical Company), TETRAD-X manufactured by Mitsubishi Gas Chemical Company, and the like.

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 0.01 to 5 parts by mass with respect to 100 parts by mass of the cross-linking (meth) acrylic copolymer. Is preferable, and 0.1 to 3 parts by mass is more preferable. By setting the content of the cross-linking agent within the above range, the processability can be further improved. As the cross-linking agent, 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.

(Polyrotaxane)
The pressure-sensitive adhesive composition contains a first polyrotaxane and a second polyrotaxane. The polyrotaxane molecule has a linear portion and a cyclic portion that is included in a state of penetrating a part of the linear portion. The polyrotaxane molecule has at least two cyclic portions, and the linear portion penetrates through the opening of the annular portion. Since the linear portion has block groups at both ends, the above configuration can be maintained without the linear portion being separated from the cyclic portion.

FIG. 2 is a schematic diagram illustrating the structure of polyrotaxane. As shown in FIG. 2, the polyrotaxane molecule 1 has at least two cyclic portions (cyclic molecules) 3 as "rotors". A linear portion (linear molecule) 2 penetrates through the openings of these annular portions 3 as a "axis", and block groups 5 are provided at both ends of the linear portion 2. The linear portion 2 of the polyrotaxane is a molecule or substance that is encapsulated in the cyclic portion 3 and can be integrated by a mechanical bond rather than a chemical bond such as a covalent bond, and may be linear. For example, there is no particular limitation. In addition, in this specification, "straight line" of "linear part" means that it is substantially "straight line". That is, the linear portion 2 may have a branched chain as long as the annular portion 3 is movable on the linear portion 2.

As shown in FIG. 2, the polyrotaxane is preferably a main chain-bound polyrotaxane. In the main chain-bound polyrotaxane, the linear portion (linear molecule) as the above-mentioned "axis" is the main chain. In the main chain-bound polyrotaxane, since the cyclic portion of the polyrotaxane has high mobility, it is possible to increase the flexibility as a molecule when incorporated into the crosslinked structure of a crosslinkable (meth) acrylic copolymer, and after post-curing. The outgas resistance and curl resistance of the adhesive sheet can be improved more effectively.

As the linear portion 2 of polyrotaxane, for example, polyethylene glycol, polypropylene glycol, polyisoprene, polyisobutylene, polybutadiene, polytetrahydrofuran, polyacrylic acid ester, polydimethylsiloxane, polyethylene, polypropylene and the like are preferable, and these linear portions are used. Part 2 may be mixed in two or more types in the pressure-sensitive adhesive composition.

The weight average molecular weight of the linear portion 2 of the polyrotaxane is preferably 1,000 or more and 300,000 or less, more preferably 3,000 or more and 100,000 or less, and further preferably 5,000 or more and 50,000 or less. By setting the weight average molecular weight of the linear portion 2 to the above lower limit value or more, the amount of movement of the annular portion 3 on the linear portion 2 can be maintained within an appropriate range, and the adhesion after post-curing can be maintained. The stress relaxation property of the agent layer can be enhanced. Further, by setting the weight average molecular weight of the linear portion 2 to the above upper limit value or less, the solubility of polyrotaxane in a solvent and the compatibility with a (meth) acrylic acid ester copolymer can be enhanced.

The cyclic portion 3 of the polyrotaxane is a molecule capable of inclusion in the linear portion 2, and is not particularly limited as long as it can move on the linear portion 2. In addition, in this specification, "annular" of "annular part" means substantially "annular". That is, the annular portion 3 does not have to be completely ring-closed, and may have a spiral structure, for example, as long as it can move on the linear portion 2.

As the cyclic portion 3 of the polyrotaxane, cyclic polymers such as cyclic polyethers, cyclic polyesters, cyclic polyether amines, and cyclic polyamines, or cyclodextrins such as α-cyclodextrin, β-cyclodextrin, and γ-cyclodextrin are preferably mentioned. Be done. Specific examples of the cyclic polymer include crown ether or its derivative, calixarene or its derivative, cyclophane or its derivative, cryptond or its derivative, and the like.

Among them, as the cyclic portion 3, cyclodextrins such as α-cyclodextrin, β-cyclodextrin, and γ-cyclodextrin are preferable, and α-cyclodextrin is more preferable. Two or more of these cyclic portions 3 may be mixed in the polyrotaxane or in the pressure-sensitive adhesive composition. The annular portion 3 is preferably used because it is relatively easy to obtain and a large number of types of block groups 5 can be selected.

At least one of the molecules constituting the cyclic portion 3 has a reactive group R1. The reactive group R1 may be a group capable of reacting with the cross-linking agent or a group not reacting with the cross-linking agent. It is preferable that each of the plurality of cyclic portions 3 has at least one reactive group R1.

The reactive group R1 of the cyclic portion 3 of the first polyrotaxane is a hydroxy group. That is, in the first polyrotaxane, the molecule constituting the cyclic portion 3 has a hydroxy group. Further, the reactive group R1 of the cyclic portion 3 of the second polyrotaxane is a vinyl group. That is, in the second polyrotaxane, the molecule constituting the cyclic portion 3 has a vinyl group. As described above, the pressure-sensitive adhesive composition contains two types of polyrotaxanes having different reactive groups in the cyclic portion 3.

Each polyrotaxane may have other substituents in addition to the reactive groups described above. Examples of other substituents include an acetyl group, an alkyl group, a trityl group, a tosyl group, a trimethylsilane group, a phenyl group, a carboxy group, an amino group and the like. The weight average molecular weight of the substituent is preferably 10,000 or less, more preferably 2000 or less. The hydroxy group contained in the cyclic portion 3 of the first polyrotaxane may be directly bonded to the cyclic portion 3, but may be bonded via another substituent as described above. Similarly, the vinyl group contained in the cyclic portion 3 of the second polyrotaxane may be directly bonded to the cyclic portion 3, but may be bonded via another substituent as described above.

The hydroxyl value of the first polyrotaxane is preferably 10 to 90 mgKOH / g. On the other hand, the hydroxyl value of the second polyrotaxane is preferably less than 10 mgKOH / g. The amount of the polymerization group in the second polyrotaxane is preferably 0.01 to 2 mmol / g, and the amount of the polymerization group in the first polyrotaxane is preferably less than 0.01 mmol / g.

The block group 5 of the polyrotaxane is not particularly limited as long as it can retain the shape in which the cyclic portion 3 is skewered by the linear portion 2. Examples of such a group include a bulky group and an ionic group. Examples of the block group 5 of the polyrotaxane include dinitrophenyl groups, cyclodextrins, adamantan groups, trityl groups, fluoresceins, pyrenes, anthracenes and the like, or polymers having a weight average molecular weight of 1000 or more and 1 million or less. The main chain or side chain of the above can be mentioned. Two or more of these block groups 5 may be mixed in the polyrotaxane.

Examples of the above-mentioned polymer having a weight average molecular weight of 1000 or more and 1 million or less listed as the block group 5 of polyrotaxane include polyamide, polyimide, polyurethane, polydimethylsiloxane, and polyacrylic acid ester.

When the annular portion 3 wraps the linear portion 2 in a skewered manner and the amount that the annular portion 3 can wrap to the maximum (inclusion amount) is 100%, the inclusion amount is 0.1% or more and 60. % Or less, more preferably 1% or more and 50% or less, and even more preferably 5% or more and 40% or less.

The maximum inclusion amount of the annular portion 3 can be determined by the length of the linear portion and the thickness of the annular portion. For example, when the linear part is polyethylene glycol and the cyclic part is an α-cyclodextrin molecule, the maximum inclusion amount can be determined experimentally (see Macromolecules 1993, 26, 5698-5703).

The weight average molecular weight of the polyrotaxane is preferably 1000 or more, more preferably 5000 or more, and further preferably 10000 or more. The weight average molecular weight of the polyrotaxane is preferably 2 million or less, more preferably 1 million or less, further preferably 500,000 or less, and particularly preferably 100,000 or less. By setting the weight average molecular weight of the polyrotaxane within the above range, it becomes easy to obtain an adhesive sheet having sufficient transparency and strength.

The weight average molecular weight of polyrotaxane is a styrene-equivalent molecular weight measured by gel permeation chromatography. The measurement conditions are as follows.
Solvent: tetrahydrofuran (THF)
Column: Shodex K806, K805, K803G (Use by connecting 3 pieces manufactured by Showa Denko KK)
Column temperature: 40 ° C
Sample concentration: 0.1% by mass
Detector: RI Model 504 (manufactured by GL Sciences)
Pump: L6000 (manufactured by Hitachi, Ltd.)
Flow rate (flow velocity): 1.0 ml / min
Injection volume: 10 μL
Calibration curve: Standard polystyrene STK standard polystyrene (manufactured by Tosoh Corporation) Mw = 500 or more and 2,800,000 or less A calibration curve with 13 samples is used. 13 samples are used at approximately equal intervals.

The content of the first polyrotaxane is preferably 0.1 to 3 parts by mass, more preferably 0.3 to 2 parts by mass with respect to 100 parts by mass of the crosslinkable (meth) acrylic copolymer. .. The content of the second polyrotaxane is preferably 0.1 to 3 parts by mass, preferably 0.3 to 2 parts by mass, based on 100 parts by mass of the crosslinkable (meth) acrylic copolymer. More preferred. By setting the content of each polyrotaxane within the above range, the pressure-sensitive adhesive layer after post-curing can exhibit sufficient stress relaxation property and can exhibit excellent curl resistance. Further, by setting the content of polyrotaxane within the above range, outgas resistance and transparency can be improved.

(Polyfunctional monomer)
The pressure-sensitive adhesive composition contains a monomer (polyfunctional monomer) having an alkylene glycol group and two (meth) acryloyl groups in the molecule. In the present invention, the polyfunctional monomer having an alkylene glycol group in one molecule also serves as a compatibilizer between the polyrotaxane and the crosslinkable (meth) acrylic copolymer, and thus the pressure-sensitive adhesive layer after post-curing. Since it is possible to increase the hardness and transparency of the adhesive layer and at the same time impart stress relaxation properties, the pressure-sensitive adhesive layer after post-curing can exhibit excellent curl resistance.

The alkylene glycol group contained in the polyfunctional monomer preferably has 1 to 5 carbon atoms, more preferably 1 to 3 carbon atoms, and particularly preferably 2 or 3 carbon atoms. That is, the polyfunctional monomer preferably has at least one selected from an ethylene glycol group and a propylene glycol group. The ethylene glycol group is −CH ₂ CH ₂ O−, and the propylene glycol group is −CH ₂ CH ₂ CH ₂ O−.
The polyfunctional monomer may have one alkylene glycol group in one molecule, or may have two or more alkylene glycol groups. The number of alkylene glycol groups in one molecule of the polyfunctional monomer is preferably 1 to 20, and more preferably 1 to 10.

Examples of such a polyfunctional monomer include polyethylene glycol diacrylate and trimethylolpropane propylene oxide-modified triacrylate.

Commercially available products can be used as the polyfunctional monomer. Examples of commercially available products include trifunctional monomer M321 (trimethylolpropane propylene oxide-modified triacrylate, Tg50 ° C.) and bifunctional monomer M240 (polyethylene glycol diacrylate, Tg50 ° C.) manufactured by Toagosei Co., Ltd.

The content of the polyfunctional monomer is preferably 1 to 20 parts by mass, and more preferably 3 to 15 parts by mass with respect to 100 parts by mass of the crosslinkable (meth) acrylic copolymer. The polyfunctional monomer may be used alone or in combination of two or more, and when two or more are used in combination, the total mass is preferably within the above range. By setting the content of the polyfunctional monomer within the above range, the hardness of the pressure-sensitive adhesive layer after post-curing can be increased more effectively, and the processability of the pressure-sensitive adhesive sheet can be improved.

(Monofunctional monomer)
The pressure-sensitive adhesive composition may contain a monofunctional monomer having one reactive double bond in the molecule, in addition to the above-mentioned monomer.

Examples of the monofunctional monomer include isobornyl acrylate, isostearyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, tetrahydrofurfuryl acrylate, benzyl methacrylate, N-acryloyloxyethyl hexahydrophthalimide, acrylamide, N, N. -Dimethylacrylamide, N, N-diethylacrylamide, acryloylmorpholin, vinylpyrrolidone and the like can be mentioned. Of these, the monofunctional monomer is preferably tetrahydrofurfuryl acrylate.

The content of such a monofunctional monomer is preferably 30 parts by mass or less, and more preferably 20 parts by mass or less, based on 100 parts by mass of the crosslinkable (meth) acrylic copolymer.

(Polymerization initiator)
The pressure-sensitive adhesive composition contains a polymerization initiator. The polymerization initiator is preferably one that initiates the polymerization of the polyfunctional monomer or the second polyrotaxane by irradiation with active energy rays, and the polymerization of the polyfunctional monomer and the second polyrotaxane by irradiation with active energy rays. It is more preferable that the above is started. As the polymerization initiator, for example, a known one such as a photopolymerization initiator can be used.
Here, the "active energy ray" means an electromagnetic wave or a charged particle beam having an energy quantum, and examples thereof include ultraviolet rays, electron beams, visible rays, X-rays, and ion rays. Among them, from the viewpoint of versatility, ultraviolet rays or electron beams are preferable, and ultraviolet rays are particularly preferable.

The polymerization initiator is preferably a photopolymerization initiator having an absorbance of 0.2 or more at a wavelength of 380 nm in an acetonitrile solution having a concentration of 0.1% by mass. By using such a polymerization initiator, the polymerization reaction of the polyfunctional monomer and the second polyrotaxane can easily proceed by irradiation with active energy rays.

The photopolymerization initiator is not particularly limited, and is, for example, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexyl-phenylketone, 2-hydroxy-2-methyl-1-henylpropanol, 1- [4-( 2-Hydroxyethoxyl) -phenyl] -2-hydroxy-methylpropanone, 2-hydroxy-1-(4- (4- (2-hydroxy-2-methylpropionyl) benzyl) phenyl) -2-methyl-1- Alkylphenone-based photopolymerization initiators such as propanone, acylphosphine oxide-based polymerization initiators such as 2,4,6-trimethylbenzoyl-diphenylphosphine oxide and 2,4,6-trimethylbenzoyl) phenylphosphine oxide, Examples thereof include intramolecular hydrogen abstraction type photopolymerization initiators such as methyl benzoylate and 4-methylbenzophenone, as well as oil-soluble polymerization initiators such as oxime ester-based photopolymerization initiators and cationic photopolymerization initiators.
Among these, the acylphosphine oxide-based photopolymerization initiator has an absorbance of 0.2 or more at a wavelength of 380 nm in an acetonitrile solution having a concentration of 0.1% by mass, so that polymerization starts even through a film or resin plate having ultraviolet absorbing performance. Therefore, it is preferable.
Commercially available products of such an acylphosphine oxide-based photopolymerization initiator include IRGACURE 819 (bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide BASF) and IRGACURE TPO (2,4,6-trimethyl). Benzoyludiphenylphosphine oxide (manufactured by BASF) and the like can be mentioned.

The content of the polymerization initiator in the pressure-sensitive adhesive composition is appropriately selected according to the content of the monomer, the irradiation amount of the active energy ray at the time of post-curing, and the like, but specifically, the crosslinkability (meth). ) With respect to 100 parts by mass of the acrylic copolymer, 0.01 to 5 parts by mass is preferable, and 0.1 to 3 parts by mass is more preferable. By setting the content of the polymerization initiator within the above range, outgas resistance and curl resistance can be more effectively enhanced. Further, the processability of the pressure-sensitive adhesive sheet can be improved by setting the content of the polymerization initiator within the above range.

(Colorant)
The pressure-sensitive adhesive composition contains a colorant. The colorant is preferably at least one selected from metal oxides and carbon black, and more preferably metal oxides. Further, the metal oxide is particularly preferably a black metal oxide. By using a metal oxide as the colorant, the visibility of the pressure-sensitive adhesive sheet can be enhanced more effectively. The colorant may contain other colorants in addition to the metal oxide and carbon black. Examples of other colorants include aniline black and activated carbon.

Metal oxides include copper oxide, iron tetraoxide, manganese dioxide, titanium oxide, zinc oxide, zirconium oxide, barium titanate, potassium titanate, iron titanate, copper-chromium oxide, copper-manganese oxide, Examples thereof include copper-iron-manganese oxide, copper-chromium-manganese oxide, copper-iron-chromine oxide, titanium black and the like. Above all, the metal oxide is more preferably a metal oxide whose metal type is selected from copper, iron and manganese. By selecting the above type as the colorant, the coloring stability becomes good.

The colorant is fine particles, and the lower limit of the average particle size of the colorant is not particularly limited, but is preferably 0.01 μm or more. The average particle size of the colorant is preferably 15 μm or less, more preferably 10 μm or less, further preferably 5 μm or less, and particularly preferably less than 1 μm. By setting the average particle size of the colorant within the above range, the visibility of the pressure-sensitive adhesive sheet can be improved more effectively.

Content per unit area of the colorant in the pressure-sensitive adhesive sheet is preferably 0.03~0.30g / ^{m 2,} more preferably from 0.05~0.25g / ^{m 2,} 0. It is particularly preferably 07 to 0.20 g / m ^2. By setting the content of the colorant per unit area within the above range, it becomes easy to improve visibility regardless of the thickness of the adhesive sheet, and further, it is possible to enhance the sense of unity with the member provided with the black frame.

The colorant is preferably mixed with the crosslinkable (meth) acrylic copolymer in a state of being dispersed in the dispersed resin. Examples of the dispersion resin include polyester resin, urethane resin, acrylic resin, and polyether resin.

(solvent)
The pressure-sensitive adhesive composition may contain a solvent. In this case, the solvent is used to improve 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, more preferably 30 to 400 parts by mass, based on 100 parts by mass of the crosslinkable (meth) acrylic copolymer.
The content of the solvent is preferably 10 to 90% by mass, more preferably 20 to 80% by mass, based on the total mass of the pressure-sensitive adhesive composition. One type of solvent may be used alone, 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.

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

As the plasticizer, for example, a non-functional group acrylic polymer may be used. The non-functional group acrylic polymer does not have a functional group such as a polymer consisting of only an acrylic monomer unit having no functional group other than an acrylate group or an acrylic monomer unit having no functional group other than an acrylate group. A polymer composed of a non-acrylic monomer unit can be mentioned. Since the non-functional group acrylic polymer is not crosslinked, it is possible to improve the step followability without affecting the adhesiveness.
Examples of the antioxidant include phenol-based antioxidants, amine-based antioxidants, lactone-based antioxidants, phosphorus-based antioxidants, sulfur-based antioxidants, and the like. One type of these antioxidants may be used alone, or two or more types may be used in combination.
As the metal corrosion inhibitor, a benzoriazole-based resin can be mentioned as a preferable example because of the compatibility and high effect of the pressure-sensitive adhesive.
Examples of the tackifier include rosin resin, terpene resin, terpene phenol resin, Kumaron inden resin, styrene resin, xylene resin, phenol resin, petroleum resin and the like.
Examples of the silane coupling agent include a mercaptoalkoxysilane compound (for example, a mercapto group-substituted alkoxy oligomer).
Examples of the ultraviolet absorber include benzotriazole-based compounds, benzophenone-based compounds, and triazine-based compounds.

<Manufacturing method of adhesive sheet>
The method for producing an 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 make a cured product in a semi-cured state. Is preferable. By heating the coating film, the reaction of the crosslinkable (meth) acrylic copolymer, the crosslinking agent and the first polyrotaxane proceeds, and the polyrotaxane is incorporated into the crosslinked structure of the crosslinkable (meth) acrylic copolymer. A cured product (adhesive layer) in a cured state is formed. That is, during heating, the polymerization reaction of the polyfunctional monomer or the second polyrotaxane by the polymerization initiator does not proceed in the coating film, or even if it progresses, it is slight, so that the pressure-sensitive adhesive is contained in the pressure-sensitive adhesive layer. The polyfunctional monomer and the second polyrotaxane contained in the composition, and at least a part of the polymerization initiator are contained in an unreacted state. As described above, the pressure-sensitive adhesive sheet of the present invention preferably has post-curability and active energy ray-curability.

In order to bring the pressure-sensitive adhesive composition into a semi-cured state, it is preferable to perform an aging treatment in which the pressure-sensitive adhesive sheet is allowed to stand at a constant temperature for a certain period of time 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 semi-cured pressure-sensitive adhesive layer can be post-cured by irradiating an adherend such as a base material with active energy rays. That is, the pressure-sensitive adhesive sheet of the present invention is a two-step curing type pressure-sensitive adhesive sheet, has a pressure-sensitive adhesive layer semi-cured only by heat before bonding, and the pressure-sensitive adhesive layer is post-cured by active energy rays after bonding. Will be done.

The coating of the pressure-sensitive 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 micro gravure coater, a rod blade coater, a lip coater, a die coater, a curtain coater and the like.

A known heating device such as a heating furnace or an infrared lamp can be used for heating 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 that the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet is brought 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 adhered to an adherend when the pressure-sensitive adhesive layer is in a semi-cured state, and the pressure-sensitive adhesive layer is post-cured by irradiating with active energy rays.

<Use of adhesive sheet>
The pressure-sensitive adhesive sheet of the present invention can suppress the generation of air bubbles even when it is attached to an adherend such as a base material, post-cured, and then exposed to a high humidity and heat environment. The pressure-sensitive adhesive sheet of the present invention is preferably a pressure-sensitive adhesive sheet used for sticking to a base material, and is a pressure-sensitive adhesive sheet used for sticking to at least one selected from a resin plate, a resin sheet and a resin film. Is more preferable.

When the pressure-sensitive adhesive sheet of the present invention is a double-sided pressure-sensitive adhesive sheet, the pressure-sensitive adhesive sheet is bonded to the first member and the second member. In this case, the first member is at least one selected from a resin plate, a resin sheet and a resin film, and the second member is at least one selected from a glass plate, a resin plate, a resin sheet and a resin film. It is preferable to have.

When a resin plate, a resin sheet or a resin film is used as the adherend, these members are preferably members containing at least one selected from a polycarbonate resin and a (meth) acrylic resin. For example, the resin plate, the resin sheet or the resin film may be a resin plate made of polycarbonate, a resin sheet or a resin film, or may be a resin plate made of (meth) acrylic resin, a resin sheet or a resin film. Further, the resin plate, the resin sheet or the resin film may be a member containing both a polycarbonate resin and a (meth) acrylic resin, and may be, for example, a laminate of a polycarbonate resin layer and a (meth) acrylic resin. ..

Examples of the polycarbonate base material include PC-1151 manufactured by Teijin Chemicals Ltd. Further, as the multilayer base material containing the polycarbonate base material, for example, MR-58U or IMR05 manufactured by Mitsubishi Gas Chemical Company, Inc. can be used. Here, the composition of MR-58U is HC (hard coat) / PMMA (polymethyl methacrylate) / PC (polycarbonate) / HC (hard coat). The overall thickness of MR-58U is preferably 0.3 mm to 1.2 mm, and the thickness of one hard coat layer is preferably 0.0005 mm to 0.02 mm. The composition of IMR05 is HC (hard coat) / PC (polycarbonate).

Further, the pressure-sensitive adhesive sheet of the present invention suppresses the generation of bubbles and peeling even when it is attached to an optical member such as a polarizing plate, post-cured, and then exposed to a high humidity and heat environment. be able to. Here, the polarizing plate includes a polarizer and a polarizer protective film, and the pressure-sensitive adhesive sheet of the present invention is preferably bonded to the polarizer protective film. The polarizer protective film includes a cycloolefin resin film, a cellulose acetate resin film such as triacetyl cellulose and diacetyl cellulose, a polyester resin film such as polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate, a polycarbonate resin film, and acrylic. Examples thereof include a based resin film and a polypropylene based resin film. In particular, when the polarizer protective film is a cellulose acetate-based resin film, the effect of suppressing the generation of bubbles is exhibited by using the pressure-sensitive adhesive sheet of the present invention.
In the present invention, since the generation of air bubbles in the adherend of the adhesive sheet can be suppressed, deterioration of visibility can be prevented when the adhesive sheet is incorporated in a display device or the like.

<Laminated body>
The present invention also relates to a laminate having the above-mentioned pressure-sensitive adhesive sheet and an adherend. In the laminated body, the pressure-sensitive adhesive layer of the above-mentioned pressure-sensitive adhesive sheet is irradiated with active energy rays and post-cured, and then the first member is provided on one surface side of the post-cured pressure-sensitive adhesive layer and the post-cured pressure-sensitive adhesive layer. It is preferable that the second member is provided on the other surface side of the pressure-sensitive adhesive layer after post-curing.

Here, the first member is at least one selected from a resin plate, a resin sheet and a resin film, and the second member is at least one selected from a glass plate, a resin plate, a resin sheet and a resin film. It is preferable to have. It is preferable that all the members are optical members. Examples of the optical member include each component in an optical product such as a touch panel and an image display device, a cover lens on the outermost layer, and the like.

When the pressure-sensitive adhesive sheet of the present invention is a double-sided pressure-sensitive adhesive sheet, the pressure-sensitive adhesive sheet can be used for bonding transparent optical films inside a touch panel, bonding a transparent optical film and glass, and bonding a transparent optical film and a liquid crystal panel for a touch panel. It may be used for bonding with a resin cover lens and a touch panel, and any member may be a member containing at least one selected from polycarbonate resin and (meth) acrylic resin. A hard coat layer may be provided on the transparent optical film or the polycarbonate base material.

<Manufacturing method of laminated body>
The method for producing a laminated body includes a step of attaching the pressure-sensitive adhesive layer of the above-mentioned pressure-sensitive adhesive sheet to an adherend in a semi-cured state and then irradiating an active energy ray to post-cure the pressure-sensitive adhesive layer. Before the irradiation with the 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 pressure-sensitive adhesive layer is post-cured with active energy rays to increase the cohesive force of the pressure-sensitive adhesive layer and improve the adhesiveness to the adherend. In addition, the post-cured pressure-sensitive adhesive layer can prevent the base material from being deformed or distorted.

Examples of the active energy ray include ultraviolet rays, electron beams, visible rays, X-rays, ion rays and the like, which can be appropriately selected depending on the polymerization initiator contained in the pressure-sensitive adhesive layer. Among them, from the viewpoint of versatility, ultraviolet rays or electron beams are preferable, and ultraviolet rays are particularly preferable.
As the light source of ultraviolet rays, 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 and the like can be used.
As the electron beam, for example, an electron beam emitted from each type of electron beam accelerator such as Cockloftwald type, Bandecliff type, resonance transformer type, insulated core transformer type, linear type, dynamitron type, and high frequency type is used. can.
Radiation output of the UV, integrated light quantity is preferably to be a 100~10000mJ / cm ^2, and more preferably made to be 500~5000mJ / cm ^2.

The features of the present invention will be described in more detail with reference to Examples and Comparative Examples. The materials, amounts used, ratios, treatment contents, treatment procedures, etc. shown in the following examples can be appropriately changed as long as they do not deviate from the gist of the present invention. Therefore, the scope of the present invention should not be construed as limited by the specific examples shown below.

(Synthesis of crosslinkable (meth) acrylic copolymer A-1)
N-butyl acrylate (BA) is blended in an amount of 70% by mass and 2-hydroxyethyl acrylate (2HEA) is blended in an amount of 30% by mass, and 2,2'-azobis (2,4-dimethylvaleronitrile) is used as a polymerization initiator. Was dissolved in the solution. The solution was heated to 60 ° C. and randomly copolymerized to obtain a crosslinkable (meth) acrylic copolymer (A-1). The crosslinkable (meth) acrylic copolymer (A-1) had a weight average molecular weight of 530,000.

(Synthesis of crosslinkable (meth) acrylic copolymer A-2)
2-Ethylhexyl acrylate (2EHA) is 45% by mass, t-butyl methacrylate (TBMA) is 20% by mass, 4-hydroxybutyl acrylate (4HBA) is 30% by mass, and acrylic acid (AA) is 5% by mass. 2,2'-Azobis (2,4-dimethylvaleronitrile) was dissolved in the solution as a polymerization initiator. The solution was heated to 60 ° C. and randomly copolymerized to obtain a crosslinkable (meth) acrylic copolymer (A-2). The crosslinkable (meth) acrylic copolymer (A-2) had a weight average molecular weight of 490,000.

(Synthesis of crosslinkable (meth) acrylic copolymer A-3)
2-Ethylhexyl acrylate (2EHA) is 65% by mass, isobornyl acrylate (IBXA) is 15% by mass, 2-hydroxyethyl acrylate (2HEA) is 15% by mass, and N-acryloylmorpholin is 5% by mass. Then, 2,2'-azobis (2,4-dimethylvaleronitrile) was dissolved in the solution as a polymerization initiator. The solution was heated to 60 ° C. and randomly copolymerized to obtain a crosslinkable (meth) acrylic copolymer (A-2). The crosslinkable (meth) acrylic copolymer (A-2) had a weight average molecular weight of 500,000.

(Example 1)
With respect to 100 parts by mass of the solid content of the crosslinkable (meth) acrylic copolymer A-1, 0.1 part by mass of a crosslinking agent (Coronate L-55 manufactured by Toso Co., Ltd.) and polyrotaxane having a hydroxyl group as the first polyrotaxane ( Advanced Soft Materials, Selm Superpolymer SH1300P) 0.5 parts by mass, Polyrotaxan having a vinyl group as the second polyrotaxan (Advanced Soft Materials, Selm Superpolymer SA1303P) 0.5 parts by mass, molecule Bifunctional monomer (tripropylene glycol diacrylate) having an alkylene glycol group inside (M220, manufactured by Toa Synthetic Co., Ltd.), 5 parts by mass, photopolymerization initiator (Irgacure819, manufactured by BASF), 0.7 parts by mass, colorant As a result, 0.05 part by mass of TM Black 3550 (metal oxide which is a copper, iron, manganese oxide, manufactured by Dainichi Seika Kogyo Co., Ltd.) is added, and a solution of ethyl acetate having a solid content concentration of 40% by mass is added. A pressure-sensitive adhesive composition was prepared by diluting and stirring so as to be.

<Making an adhesive sheet>
A 38 μm-thick polyethylene terephthalate film (first release sheet) (manufactured by Oji F-Tex Co., Ltd., 38RL-07) having a release agent layer treated with a silicone-based release agent on the pressure-sensitive adhesive composition prepared as described above. The surface of (2)) is uniformly coated with an applicator so that the coating thickness after drying is 150 μm, dried in an air circulation type constant temperature oven at 100 ° C. for 3 minutes, and then applied to the surface of the first release sheet. A pressure-sensitive adhesive layer was formed. Next, a second release sheet having a thickness of 38 μm (38RL-07 (L) manufactured by Oji F-Tex Co., Ltd.) was attached to the surface of the pressure-sensitive adhesive layer. In this way, an adhesive sheet with a release sheet having a structure of a first release sheet / an adhesive layer / a second release sheet in which the adhesive layer is sandwiched between a pair of release sheets having a difference in release force was obtained. .. The adhesive sheet was cured at 23 ° C. and a relative humidity of 50% for 7 days. The content of the colorant per unit area in the pressure-sensitive adhesive sheet was 0.075 g / m ² .

(Example 2)
The second polyrotaxane (containing vinyl group) was changed to SA2403P (manufactured by Advanced Soft Materials), and the bifunctional monomer having an alkylene glycol group in the molecule was changed to polyethylene glycol diacrylate (manufactured by Toagosei Co., Ltd., M240). ) Was obtained in the same manner as in Example 1 to obtain an adhesive composition and an adhesive sheet with a release sheet.

(Example 3)
With respect to 100 parts by mass of the solid content of the crosslinkable (meth) acrylic copolymer A-2, 0.05 parts by mass of a crosslinking agent (Tetrad C manufactured by Mitsubishi Gas Chemicals, Inc.) and a polyrotaxane having a hydroxyl group as the first polyrotaxane ( 1 part by mass of Selm Superpolymer SH2400P, manufactured by Advanced Soft Materials, 2 parts by mass of polyrotaxan (Selm Superpolymer SA1303P, manufactured by Advanced Soft Materials) having a vinyl group as the second polyrotaxan, alkylene glycol in the molecule. 10 parts by mass of a bifunctional monomer (tripropylene glycol diacrylate) having a group (M220 manufactured by Toa Synthetic Co., Ltd.), 1 part by mass of a photopolymerization initiator (IrgacureTPO manufactured by BASF Co., Ltd.), TM Black 3550 (manufactured by BASF) as a colorant Add 0.05 parts by mass of copper, iron, metal oxide which is a manganese-based oxide, manufactured by Dainichi Seika Kogyo Co., Ltd., and dilute and stir with ethyl acetate so that the solution has a solid content concentration of 40% by mass. A pressure-sensitive adhesive composition was prepared.
A pressure-sensitive adhesive sheet with a release sheet was obtained in the same manner as in Example 1 except that the pressure-sensitive adhesive composition prepared as described above was used.

(Example 4)
The second polyrotaxane (containing vinyl group) was changed to SA2403P (manufactured by Advanced Soft Materials), and the bifunctional monomer having an alkylene glycol group in the molecule was changed to polyethylene glycol diacrylate (manufactured by Toagosei Co., Ltd., M240). ) Was obtained, and the pressure-sensitive adhesive composition and the pressure-sensitive adhesive sheet with the release sheet were obtained in the same manner as in Example 3.

(Example 5)
An adhesive sheet with a release sheet was obtained in the same manner as in Example 1 except that the amount of the colorant added was changed to 0.09 parts by mass. The content of the colorant per unit area in the pressure-sensitive adhesive sheet was 0.135 g / m ² .

(Example 6)
An adhesive sheet with a release sheet was obtained in the same manner as in Example 2 except that the amount of the colorant added was changed to 0.09 parts by mass.

(Example 7)
An adhesive sheet with a release sheet was obtained in the same manner as in Example 3 except that the amount of the colorant added was changed to 0.09 parts by mass.

(Example 8)
An adhesive sheet with a release sheet was obtained in the same manner as in Example 4 except that the amount of the colorant added was changed to 0.09 parts by mass.

(Example 9)
An adhesive sheet with a release sheet was obtained in the same manner as in Example 1 except that the amount of the colorant added was changed to 0.16 parts by mass. The content of the colorant per unit area in the pressure-sensitive adhesive sheet was 0.24 g / m ² .

(Example 10)
An adhesive sheet with a release sheet was obtained in the same manner as in Example 2 except that the amount of the colorant added was changed to 0.16 parts by mass.

(Example 11)
An adhesive sheet with a release sheet was obtained in the same manner as in Example 3 except that the amount of the colorant added was changed to 0.16 parts by mass.

(Example 12)
An adhesive sheet with a release sheet was obtained in the same manner as in Example 4 except that the amount of the colorant added was changed to 0.16 parts by mass.

(Comparative Example 1)
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 no colorant was added.

(Comparative Example 2)
Polyrotaxane having 0.05 parts by mass of a cross-linking agent (Tetrad C, manufactured by Mitsubishi Gas Chemicals, Inc.) and a vinyl group as a second polyrotaxane with respect to 100 parts by mass of the solid content of the crosslinkable (meth) acrylic copolymer A-2. (Celm Superpolymer SA1303P, manufactured by Advanced Soft Materials), 3 parts by mass, bifunctional monomer (tripropylene glycol diacrylate) having an alkylene glycol group in the molecule (M220, manufactured by Toa Synthetic Co., Ltd.), 10 parts by mass, 1 part by mass of a photopolymerization initiator (IrgacureTPO manufactured by BASF) was added, and the mixture was diluted and stirred with ethyl acetate so as to have a solid content concentration of 40% by mass to prepare a pressure-sensitive adhesive composition.
A pressure-sensitive adhesive sheet with a release sheet was obtained in the same manner as in Example 1 except that the pressure-sensitive adhesive composition prepared as described above was used.

(Comparative Example 3)
Polyrotaxane (advanced soft) having 0.25 parts by mass of a cross-linking agent (Coronate L-55 manufactured by Toso Co., Ltd.) and a hydroxyl group as a polyrotaxane with respect to 100 parts by mass of the solid content of the crosslinkable (meth) acrylic copolymer A-3. Selm Superpolymer SH3400P, manufactured by Materials, 7.5 parts by mass, polyfunctional monomer without alkylene glycol group in the molecule (ε-caprolactone-modified tris- (2-acryloxyethyl) isocyanurate) (new 5.13 parts by mass of A-9300-1CL (manufactured by Nakamura Chemical Co., Ltd.) and 0.57 parts by mass of a photopolymerization initiator (IrgacureTPO manufactured by BASF) were added, and a solution having a solid content concentration of 40% by mass was prepared with ethyl acetate. A pressure-sensitive adhesive composition was prepared by diluting and stirring so as to be.
A pressure-sensitive adhesive sheet with a release sheet was obtained in the same manner as in Example 1 except that the pressure-sensitive adhesive composition prepared as described above was used.

(Comparative Example 4)
As a colorant, TM Black 3550 (copper, iron, metal oxide which is a manganese-based oxide, manufactured by Dainichi Seika Kogyo Co., Ltd.) was added in an amount of 0.16 parts by mass in the same manner as in Comparative Example 3. A pressure-sensitive adhesive composition and a pressure-sensitive adhesive sheet with a release sheet were obtained. The content of the colorant per unit area in the pressure-sensitive adhesive sheet was 0.24 g / m ² .

(Comparative Example 5)
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 no colorant was added.

(Comparative Example 6)
A pressure-sensitive adhesive composition and a pressure-sensitive adhesive sheet with a release sheet were obtained in the same manner as in Example 2 except that no colorant was added.

(Comparative Example 7)
A pressure-sensitive adhesive composition and a pressure-sensitive adhesive sheet with a release sheet were obtained in the same manner as in Example 3 except that no colorant was added.

(Comparative Example 8)
A pressure-sensitive adhesive composition and a pressure-sensitive adhesive sheet with a release sheet were obtained in the same manner as in Example 4 except that no colorant was added.

(Comparative Example 9)
0.1 part by mass of a cross-linking agent (Tosoh Co., Ltd., Coronate L-55) and TM Black 3550 (copper, as a colorant) with respect to 100 parts by mass of the solid content of the crosslinkable (meth) acrylic copolymer A-2. Add 0.16 parts by mass of iron, metal oxide which is a manganese-based oxide, and manufactured by Dainichi Seika Kogyo Co., Ltd., and dilute and stir with ethyl acetate to obtain a solution with a solid content concentration of 40% by mass. The agent composition was prepared.
A pressure-sensitive adhesive sheet with a release sheet was obtained in the same manner as in Example 1 except that the pressure-sensitive adhesive composition prepared as described above was used. The content of the colorant per unit area in the pressure-sensitive adhesive sheet was 0.24 g / m ² .

[Measurement and evaluation]
<Content of colorant>
The content of the colorant per unit area (g / m ² ) in the pressure-sensitive adhesive sheet was calculated according to the following formula.
Colorant content per unit area = Number of copies of colorant added / 100 x Adhesive sheet thickness (μm)

<Outgas resistance>
The outgas resistance evaluation was performed as follows using the adhesive sheet with a release sheet prepared in Examples and Comparative Examples.
In the pressure-sensitive adhesive sheet with a release sheet, the second release sheet, which is a light separator film, is peeled off to expose the pressure-sensitive adhesive layer, and the pressure-sensitive adhesive layer is attached to a glass plate having a size of 100 mm × 200 mm as a first member. I matched it. Next, the first release sheet, which is a heavy separator film, is peeled off, and the exposed adhesive layer is a polycarbonate resin plate (Teijin Co., Ltd.) having a size of 120 mm × 220 mm and a thickness of 1 mm, which is one size larger than the above glass as a second member. It was affixed to the entire surface in the center of the panlight sheet PC-1151) made of the same product. As a result, a laminate sample composed of a polycarbonate resin plate / adhesive layer / glass plate was obtained. After treating the laminated body sample in an autoclave at 40 ° C. and 0.5 MPa for 30 minutes, ultraviolet rays are irradiated from the polycarbonate resin plate side so that the integrated light intensity is 3000 mJ / cm ^2, and the bonded area area is 100 mm × 200 mm. A test sample of the size of was obtained. The test sample was placed in an environment of 85 ° C. and a relative humidity of 85%, and after 2 hours and 100 hours, the test sample was visually observed, and air bubbles, floating and peeling were evaluated according to the following three criteria. ..
◯: No bubbles, floats or peeling were observed after 2 hours or 100 hours Δ: Micro bubbles were observed after 2 hours, but no bubbles, floats or peeling were observed after 100 hours × : Bubbles, floats and peeling were observed after 2 hours and 100 hours.

(Test Example 2)
In the above (Test Example 1), the second member has a size of 120 mm × 220 mm and a thickness of 1 mm instead of a polycarbonate resin plate (Panlite sheet PC-1151 manufactured by Teijin Limited) having a size of 120 mm × 220 mm and a thickness of 1 mm. The evaluation was carried out in the same manner as in Test Example 1 except that the polycarbonate side of a polycarbonate resin plate (Iupilon sheet MR-58U manufactured by Mitsubishi Gas Chemical Company, Inc.) in which PMMA was laminated on one side was attached.

<Curl resistance>
A sample prepared in the same manner as in Test Example 2 of outgas resistance described above is treated in an oven at 105 ° C. (relative humidity is 20% or less) for 24 hours, and then taken out and the convex surface curled into a horizontal plane is turned down within 5 minutes. The sample was allowed to stand as described above, and the heights of the four corners of the sample from the waterside surface were measured to obtain an average value, which was evaluated according to the following criteria.
◯: Less than 5 mm ×: 5 mm or more

<Design>
A sample was prepared in the same manner as the optical characteristic measurement, and evaluated by placing it on a display displaying a black screen.
○: It looked blacker than when nothing was put on it ×: No change

<Visibility>
A sample was prepared in the same manner as the optical characteristic measurement, and evaluated by placing it on a display displaying characters.
○: No bleeding or blurring △: Bleeding or blurring is seen ×: Bleeding or blurring is seen and the characters cannot be read

<Total light transmittance>
The light peeling separator, which is the second peeling sheet, was peeled off, and a PET film (Cosmoshine A4300 # 100 manufactured by Toyobo Co., Ltd.) was laminated using a hand roller in place of the peeled separator to prepare a laminated film. This laminated film was cut into a size of 50 mm in width and 50 mm in length, and the first release sheet was peeled off. Next, the exposed adhesive surface was attached to a slide glass (manufactured by Matsunami Glass Co., Ltd., S9112) using a hand roller. In this state, it was held in an autoclave under the conditions of 40 ° C. and 5 atm for 30 minutes to be brought into close contact with the glass plate.
The total light transmittance of the obtained laminate was measured using an integrating sphere type light transmittance measuring device (NDH-5000, manufactured by Nippon Denshoku Kogyo Co., Ltd.) in accordance with JIS K 7150. This measurement was performed three times, and the average value was taken as the measured value.

SH1300P: Overall weight average molecular weight 180,000, Linear part weight average molecular weight 11,000 SH2400P: Overall weight average molecular weight 400,000, Linear part weight average molecular weight 20,000 SH3400P: Overall weight average molecular weight 700,000 SA1303: Overall weight average molecular weight 180,000, Linear part weight average molecular weight 11,000 SA2403: Overall weight average molecular weight 600,000, Linear part weight average Molecular weight 20,000

From the above results, it was found that the adhesive sheet of the example was excellent in designability in addition to outgas resistance and curl resistance.

1 Polyrotaxane molecule 2 Linear part 3 Cyclic part 5 Block group 10 Adhesive sheet with release sheet 11 Adhesive sheet (adhesive layer)
12a release sheet 12b release sheet

Claims (15)

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 is a crosslinkable (meth) acrylic copolymer, a crosslinker, a first polyrotaxane, a second polyrotaxane, a single amount having an alkylene glycol group in the molecule and two (meth) acryloyl groups. Contains body, polymerization initiator and colorant,
The first polyrotaxane has a linear portion and a cyclic portion that is included in a state of penetrating a part of the linear portion, and the molecule constituting the cyclic portion has a hydroxy group.
The second polyrotaxane has a linear portion and an annular portion that is included in a state of penetrating a part of the linear portion, and the molecule constituting the cyclic portion has a vinyl group, and is an adhesive sheet. .. The adhesive sheet according to claim 1, wherein the total light transmittance is 5 to 90%. The pressure-sensitive adhesive sheet according to claim 1 or 2, wherein the colorant is at least one selected from metal oxides and carbon black. The pressure-sensitive adhesive sheet according to any one of claims 1 to 3, wherein the colorant is a metal oxide. The pressure-sensitive adhesive sheet according to any one of claims 1 to 4, wherein the average particle size of the colorant is 0.01 μm or more and less than 5 μm. The adhesive according to any one of claims 1 to 5, wherein the content of the first polyrotaxane is 0.1 to 3 parts by mass with respect to 100 parts by mass of the crosslinkable (meth) acrylic copolymer. Sheet. The adhesive according to any one of claims 1 to 6, wherein the content of the second polyrotaxane is 0.1 to 3 parts by mass with respect to 100 parts by mass of the crosslinkable (meth) acrylic copolymer. Sheet. The pressure-sensitive adhesive sheet according to any one of claims 1 to 7, wherein the content of the monomer is 1 to 20 parts by mass with respect to 100 parts by mass of the crosslinkable (meth) acrylic copolymer. The pressure-sensitive adhesive sheet according to any one of claims 1 to 8, wherein the polymerization initiator is a photopolymerization initiator having an absorbance at a wavelength of 380 nm of 0.2 or more in an acetonitrile solution having a concentration of 0.1% by mass. The pressure-sensitive adhesive sheet according to any one of claims 1 to 9, wherein the cross-linking agent is at least one selected from a 2-4-functional isocyanate-based cross-linking agent and a 2-4-functional epoxy-based cross-linking agent. For bonding the first member,
The pressure-sensitive adhesive sheet according to any one of claims 1 to 10, wherein the first member is at least one selected from a resin plate, a resin sheet, and a resin film. For bonding the second member,
The pressure-sensitive adhesive sheet according to any one of claims 1 to 11, wherein the second member is at least one selected from a glass plate, a resin plate, a resin sheet, and a resin film. The pressure-sensitive adhesive sheet according to claim 11 or 12, wherein the resin plate, the resin sheet, and the resin film contain at least one selected from a polycarbonate resin and a (meth) acrylic resin. A pressure-sensitive adhesive sheet with a release sheet, comprising a pair of release sheets having different peeling forces on both surfaces of the pressure-sensitive adhesive sheet according to any one of claims 1 to 13. One of a post-curing pressure-sensitive adhesive layer and a post-curing pressure-sensitive adhesive layer after irradiating the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet according to any one of claims 1 to 13 with active energy rays and post-curing. A laminate having a first member on the surface side of the adhesive layer and a second member on the other surface side of the post-curing pressure-sensitive adhesive layer.

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