JP7099206B2 - Double-sided adhesive sheet and double-sided adhesive sheet with release sheet - Google Patents

Description

The present invention relates to a double-sided adhesive sheet and a double-sided adhesive sheet with a release sheet.

In recent years, in various fields, display devices such as liquid crystal displays (LCDs) and image display devices that combine display devices such as touch panels and input devices have been widely used. In these display devices and input devices, double-sided adhesive sheets are used for bonding optical members.

The double-sided adhesive sheet may be used for bonding different types of adherends. In this case, the double-sided adhesive sheet is required to have an optimum adhesive force according to the adhesive characteristics of each adherend. For example, Patent Documents 1 and 2 disclose a double-sided pressure-sensitive adhesive sheet having two or more pressure-sensitive adhesive layers having different pressure-sensitive adhesive properties.

In display devices and input devices, the surface thereof is covered with a protective sheet in order to protect the display surface. The protective sheet is composed of, for example, a glass sheet provided with an adhesive layer, and by attaching the protective sheet to the display surface, cracking or scratching of the liquid crystal display is suppressed. When such a protective sheet is used, it may be necessary to rework (re-peel) the protective sheet in order to correct the bonding position or replace the protective sheet due to aged deterioration. For example, Patent Documents 3 and 4 disclose a double-sided pressure-sensitive adhesive sheet having at least two pressure-sensitive adhesive layers and configured to be removable with respect to the display surface of the display device. In the examples of Patent Document 3, each pressure-sensitive adhesive layer is formed from different types of acrylic polymers, and it is studied to improve the durability and reworkability of the double-sided pressure-sensitive adhesive sheet. The double-sided adhesive sheet of Patent Document 3 is intended for attaching a display surface and a touch panel. Further, Patent Document 4 discloses a double-sided pressure-sensitive adhesive sheet having a first pressure-sensitive adhesive layer and a second pressure-sensitive adhesive layer on both surfaces of the core material, and the first pressure-sensitive adhesive layer is a silicone-based pressure-sensitive adhesive. An acrylic pressure-sensitive adhesive is used for the agent, and an acrylic pressure-sensitive adhesive is used for the second pressure-sensitive adhesive layer.

Japanese Unexamined Patent Publication No. 5-17725 Japanese Unexamined Patent Publication No. 2011-57883 Japanese Unexamined Patent Publication No. 2004-231723 Japanese Patent No. 6197102

However, when the double-sided adhesive sheet in the prior art is peeled off from the adherend again, there is a problem that the adhesive remains on the adherend during the reworking operation. If the adhesive remains on the adherend, it is necessary to wipe off the adhesive with a solvent or wash it, which is a problem because the reworking work takes time and effort. In particular, a protective sheet for general consumers who cannot use special equipment, jigs, and chemicals to perform laminating and reworking work needs to be able to be easily reworked from the display surface. It is necessary to make the adhesive strength extremely low. On the other hand, the double-sided adhesive sheet used for the protective sheet needs to be firmly adhered to the object to be adhered on the side opposite to the display surface. In general, it is difficult to stack adhesive layers having contradictory adhesive properties in this way, so a double-sided adhesive sheet in which a base film is provided between a slightly adhesive layer and a strong adhesive layer is used. There is. However, the double-sided adhesive sheet in which the base film is provided between the slightly adhesive layer and the strong adhesive layer tends to increase in thickness, has poor unevenness followability, and cannot meet the recent demand for thinning. There was a problem.

Therefore, in order to solve the problems of the prior art, the present inventors have excellent on one side of the double-sided pressure-sensitive adhesive sheet while exhibiting a strong adhesive force against the adherend. We proceeded with the study for the purpose of providing a double-sided pressure-sensitive adhesive sheet that can exhibit reworkability and does not contain a base film.

As a result of diligent studies to solve the above problems, the present inventors directly laminate the silicone-based pressure-sensitive adhesive layer on the acrylic-based pressure-sensitive adhesive layer containing an acrylic copolymer composed of a predetermined monomer unit. As a result, it has been found that a double-sided adhesive sheet having both strong adhesive strength and excellent reworkability, which does not contain a base film, can be obtained.
Specifically, the present invention has the following configurations.

[1] Acrylic adhesive layer and
It has a silicone-based pressure-sensitive adhesive layer directly laminated on the acrylic-based pressure-sensitive adhesive layer, and has.
The acrylic pressure-sensitive adhesive layer has an acrylic copolymer containing a unit derived from butyl acrylate, and has an acrylic copolymer.
A double-sided pressure-sensitive adhesive sheet in which the content of a unit derived from butyl acrylate is 30% by mass or more with respect to the total mass of the acrylic copolymer.
[2] The acrylic copolymer further contains a unit derived from -2-hydroxyethyl acrylate, and the content of the unit derived from -2-hydroxyethyl acrylate is based on the total mass of the acrylic copolymer. The double-sided adhesive sheet according to [1], which is 10% by mass or more and 50% by mass or less.
[3] The acrylic copolymer further contains a unit derived from -2-methoxyethyl acrylate, and the content of the unit derived from -2-methoxyethyl acrylate is based on the total mass of the acrylic copolymer. The double-sided adhesive sheet according to [1], which is 10% by mass or more and 50% by mass or less.
[4] The double-sided surface according to any one of [1] to [3], wherein the acrylic copolymer further contains at least one selected from a unit derived from -2-ethylhexyl acrylic acid and a unit derived from acrylic acid. Adhesive sheet.
[5] The double-sided pressure-sensitive adhesive sheet according to any one of [1] to [4], wherein the interfacial adhesive strength between the acrylic pressure-sensitive adhesive layer and the silicone-based pressure-sensitive adhesive layer is 1 N / 25 mm or more.
[6] The double-sided pressure-sensitive adhesive sheet according to any one of [1] to [5], wherein the acrylic pressure-sensitive adhesive layer has an adhesive strength against glass of 1 N / 25 mm or more and 30 N / 25 mm or less.
[7] The double-sided pressure-sensitive adhesive sheet according to any one of [1] to [6], wherein the silicone-based pressure-sensitive adhesive layer has an adhesive strength against glass of 0.005 N / 25 mm or more and 1 N / 25 mm or less.
[8] The surface according to any one of [1] to [7], wherein the surface of the silicone-based pressure-sensitive adhesive layer on the interface side is the surface-activated surface, and the wet tension of the surface-activated surface is 30 mN / m or more. Double-sided adhesive sheet.
[9] A double-sided adhesive sheet with a release sheet provided with release sheets on both sides of the double-sided adhesive sheet according to any one of [1] to [8].

According to the present invention, one surface of the double-sided adhesive sheet is a double-sided adhesive sheet capable of exhibiting strong adhesive force to the adherend, while the other surface is capable of exhibiting excellent reworkability. A double-sided adhesive sheet containing no material film can be obtained.

FIG. 1 is a cross-sectional view illustrating the configuration of the double-sided pressure-sensitive adhesive sheet of the present invention.

Hereinafter, the present invention will be described in detail. The description of the constituent elements described below may be based on typical embodiments and specific examples, but the present invention is not limited to such embodiments.

(Double-sided adhesive sheet)
The present invention relates to a double-sided pressure-sensitive adhesive sheet having an acrylic pressure-sensitive adhesive layer and a silicone-based pressure-sensitive adhesive layer directly laminated on the acrylic pressure-sensitive adhesive layer. Here, the acrylic pressure-sensitive adhesive layer has an acrylic copolymer containing a unit derived from butyl acrylate, and the content of the unit derived from butyl acrylate is based on the total mass of the acrylic copolymer. It is 30% by mass or more. Since the double-sided pressure-sensitive adhesive sheet of the present invention has a plurality of pressure-sensitive adhesive layers in this way, it can also be called a double-sided laminated pressure-sensitive adhesive sheet.

Since the double-sided pressure-sensitive adhesive sheet of the present invention has the above-mentioned structure, it is excellent in reworkability. Here, the excellent reworkability is that a part of the adhesive of the double-sided adhesive sheet does not remain on the adherend when the double-sided adhesive sheet is attached to the adherend and then peeled off, and the rework work is performed. It refers to the property that the double-sided adhesive sheet does not break inside. Further, one surface of the double-sided adhesive sheet of the present invention can exert a strong adhesive force against the adherend. In particular, the double-sided adhesive sheet of the present invention can exert a strong adhesive force against the glass surface. As described above, the double-sided adhesive sheet of the present invention has both strong adhesive strength and excellent reworkability.

FIG. 1 is a cross-sectional view illustrating the configuration of the double-sided pressure-sensitive adhesive sheet of the present invention. The double-sided pressure-sensitive adhesive sheet 100 of the present invention has an acrylic pressure-sensitive adhesive layer 10 and a silicone-based pressure-sensitive adhesive layer 12. As shown in FIG. 1, the double-sided pressure-sensitive adhesive sheet 100 preferably has a structure in which an acrylic pressure-sensitive adhesive layer 10 and a silicone-based pressure-sensitive adhesive layer 12 are laminated one by one, but each layer includes two or more layers. May be good. For example, the acrylic pressure-sensitive adhesive layer 10 shown as a one-layer structure in FIG. 1 may have a laminated structure of two or more acrylic pressure-sensitive adhesive layers, and the silicone-based pressure-sensitive adhesive layer 12 may have two layers. It may have the above-mentioned laminated structure of the silicone-based pressure-sensitive adhesive layer.

As shown in FIG. 1, the double-sided pressure-sensitive adhesive sheet of the present invention is a double-sided pressure-sensitive adhesive sheet having no support (base material). Therefore, in the double-sided pressure-sensitive adhesive sheet, the acrylic pressure-sensitive adhesive layer and the silicone-based pressure-sensitive adhesive layer are laminated in direct contact with each other. Therefore, the double-sided pressure-sensitive adhesive sheet of the present invention can be thinned as needed. Further, since the double-sided adhesive sheet of the present invention is a double-sided adhesive sheet that does not have a support (base material), it is excellent in curved surface followability and further excellent in step followability. The layer in contact with the step structure may be an acrylic pressure-sensitive adhesive layer or a silicone-based pressure-sensitive adhesive layer.

Further, since the double-sided adhesive sheet of the present invention has the above-mentioned structure, the air bleeding property to the display surface is also good. In the present specification, the air bleeding property means a property that bubbles do not remain at the interface between the pressure-sensitive adhesive layer and the adherend when the double-sided pressure-sensitive adhesive sheet is attached to the adherend.

In the double-sided pressure-sensitive adhesive sheet of the present invention, the interfacial adhesive force between the acrylic pressure-sensitive adhesive layer and the silicone-based pressure-sensitive adhesive layer is preferably 1N / 25 mm or more, more preferably 5N / 25 mm or more, and 10N / 25 mm or more. It is more preferable to have it, and it is particularly preferable that it is 15 N / 25 mm or more. The upper limit of the interfacial adhesive force between the acrylic pressure-sensitive adhesive layer and the silicone-based pressure-sensitive adhesive layer is not particularly limited, but is preferably 100 N / 25 mm, for example. As described above, in the double-sided pressure-sensitive adhesive sheet of the present invention, the acrylic pressure-sensitive adhesive layer and the silicone-based pressure-sensitive adhesive layer are firmly adhered to each other and have excellent interlayer adhesion. By setting the interfacial adhesive force between the acrylic pressure-sensitive adhesive layer and the silicone-based pressure-sensitive adhesive layer within the above range, peeling can occur between the acrylic-based pressure-sensitive adhesive layer and the silicone-based pressure-sensitive adhesive layer when reworking the double-sided pressure-sensitive adhesive sheet. It is possible to suppress the occurrence, and as a result, the reworkability can be enhanced.

The interfacial adhesive strength between the acrylic pressure-sensitive adhesive layer and the silicone-based pressure-sensitive adhesive layer can be measured after preparing a sample for measuring the interfacial adhesive strength as described in Examples.
The interfacial adhesive strength is 24 hours after obtaining "polyethylene terephthalate film with easy adhesive layer / acrylic adhesive layer / silicone adhesive layer / adhesive tape with backing substrate" as described in Examples (surface activation treatment). 24 hours after attaching the silicone-based adhesive layer surface and the acrylic-based adhesive layer surface), the adhesive tape side with the backing base material was peeled off according to Method 1 of JIS Z 0237, with a peeling speed of 300 mm / min and a peeling angle. By peeling off under the condition of 180 °, the adhesive strength of the "acrylic adhesive layer / silicone adhesive layer" interface is measured.

The adhesive force with respect to the glass on one side of the double-sided pressure-sensitive adhesive sheet of the present invention is preferably 1N / 25 mm or more, more preferably 5N / 25 mm or more, and further preferably 10N / 25 mm or more. Further, the adhesive force against the glass on one surface side of the double-sided adhesive sheet is preferably 30 N / 25 mm or less. The adhesive strength is preferably the adhesive strength on the acrylic pressure-sensitive adhesive layer side of the double-sided pressure-sensitive adhesive sheet, and the adhesive strength against the glass of the acrylic pressure-sensitive adhesive layer is preferably within the above range.

Further, the adhesive force against the glass on the other side of the double-sided pressure-sensitive adhesive sheet of the present invention is preferably 0.005 N / 25 mm or more, and more preferably 0.05 N / 25 mm or more. Further, the adhesive force against the glass on the other surface side of the double-sided adhesive sheet is preferably 1.0 N / 25 mm or less, and more preferably 0.5 N / 25 mm or less. The adhesive force is preferably the adhesive force on the silicone-based adhesive layer side of the double-sided adhesive sheet, and the adhesive force against the glass of the silicone-based adhesive layer is preferably within the above range.

The adhesive strength of the double-sided adhesive sheet against glass is as follows: peeling speed 300 mm / min, peeling angle according to Method 1 of JIS Z 0237 24 hours after the adhesive surface of each pressure-sensitive adhesive layer is attached to soda glass. It is a value measured under the condition of 180 °. By setting the adhesive force against glass of each adhesive layer within the above range, a double-sided adhesive sheet having both strong adhesive force and excellent reworkability can be obtained.

The total thickness of the double-sided pressure-sensitive adhesive sheet of the present invention is preferably 10 μm or more, more preferably 20 μm or more, and further preferably 50 μm or more. The total thickness of the double-sided pressure-sensitive adhesive sheet is preferably 1000 μm or less, more preferably 800 μm or less, and even more preferably 600 μm or less. By setting the overall thickness of the double-sided adhesive sheet within the above range, it becomes easy to achieve both strong adhesive strength and excellent reworkability.

The thickness of one layer of the acrylic pressure-sensitive adhesive layer in the double-sided pressure-sensitive adhesive sheet of the present invention is preferably 5 μm or more, more preferably 10 μm or more, and further preferably 25 μm or more. The thickness of the acrylic pressure-sensitive adhesive layer is preferably 500 μm or less, more preferably 400 μm or less, and even more preferably 300 μm or less.

The thickness of one layer of the silicone-based pressure-sensitive adhesive layer in the double-sided pressure-sensitive adhesive sheet of the present invention is preferably 5 μm or more, more preferably 10 μm or more, and further preferably 25 μm or more. The thickness of the silicone-based pressure-sensitive adhesive layer is preferably 500 μm or less, more preferably 400 μm or less, and even more preferably 300 μm or less.

In the present invention, when the thickness (μm) of the acrylic pressure-sensitive adhesive layer is P and the thickness (μm) of the silicone-based pressure-sensitive adhesive layer is Q, P: Q = 1:10 to 10: 1. preferable. By setting P: Q within the above range, one surface of the double-sided adhesive sheet exhibits strong adhesive force to the adherend, while the other surface exhibits excellent reworkability. It becomes easier to obtain a sheet. The above-mentioned P represents the total thickness of the acrylic pressure-sensitive adhesive layers when the double-sided pressure-sensitive adhesive sheet contains two or more acrylic pressure-sensitive adhesive layers, and the above-mentioned Q represents the total thickness of the acrylic-based pressure-sensitive adhesive layer. When two or more layers are included, it represents the total thickness of the silicone-based pressure-sensitive adhesive layers.

The haze of the double-sided pressure-sensitive adhesive sheet of the present invention is preferably 3% or less, and more preferably 1% or less. In the present specification, the haze of the double-sided adhesive sheet refers to a value measured by a method according to JIS K 7136. When measuring the haze, the double-sided adhesive sheet of the present invention is attached to a slide glass (product number: S9112) manufactured by Matsunami Glass Co., Ltd., and the haze value is measured. Specifically, after the double-sided adhesive sheet is bonded to a slide glass manufactured by Matsunami Glass Co., Ltd., in order to eliminate the influence of fine air mixed during the bonding, 0.5 MPa, 40 ° C. is applied to the laminated sample. Perform autoclave (pressure defoaming) treatment for 30 minutes under the conditions of. After that, the peeling sheet on the opposite side to the glass-bonded surface is peeled off, and the measurement is performed using NDH4000 manufactured by Nippon Denshoku Kogyo Co., Ltd. with the glue surface exposed.

The total light transmittance of the double-sided pressure-sensitive adhesive sheet of the present invention is preferably 80% or more, more preferably 85% or more, and further preferably 90% or more. The double-sided adhesive sheet of the present invention is characterized in that it has a high total light transmittance and is excellent in transparency. In the present specification, the total light transmittance of the double-sided adhesive sheet refers to a value measured by a method according to JIS K 7136. The total light transmittance of the double-sided adhesive sheet can be measured by the same method as the above-mentioned method for measuring the haze value.

Further, the double-sided adhesive sheet of the present invention is also excellent in flexibility. Therefore, even if the adherend is a member having a curved surface or a stepped portion, it can be attached following the curved surface or the stepped portion.

<Acrylic adhesive layer>
The double-sided pressure-sensitive adhesive sheet of the present invention includes an acrylic pressure-sensitive adhesive layer. The acrylic pressure-sensitive adhesive layer is a layer containing an acrylic copolymer as a main component. Specifically, the content of the acrylic copolymer in the acrylic pressure-sensitive adhesive layer is preferably 50% by mass or more, more preferably 60% by mass or more, based on the total mass of the acrylic pressure-sensitive adhesive layer. It is more preferably 70% by mass or more, further preferably 80% by mass or more, and particularly preferably 90% by mass or more.

In the present invention, the acrylic copolymer contained in the acrylic pressure-sensitive adhesive layer contains a unit derived from butyl acrylate. The content of the unit derived from butyl acrylate may be 30% by mass or more, preferably 35% by mass or more, and more preferably 40% by mass or more, based on the total mass of the acrylic copolymer. More preferred. The content of the unit derived from butyl acrylate is preferably 80% by mass or less, more preferably 70% by mass or less, based on the total mass of the acrylic copolymer. By setting the content of the unit derived from butyl acrylate in the acrylic copolymer within the above range, the interfacial adhesive strength between the acrylic pressure-sensitive adhesive layer and the silicone-based pressure-sensitive adhesive layer can be effectively enhanced. The reworkability of the double-sided adhesive sheet can be improved.

The acrylic copolymer contained in the acrylic pressure-sensitive adhesive layer preferably further contains a unit derived from -2-hydroxyethyl acrylate in addition to the unit derived from butyl acrylate. In this case, the content of the unit derived from -2-hydroxyethyl acrylate is preferably 10% by mass or more, more preferably 15% by mass or more, based on the total mass of the acrylic copolymer. , 20% by mass or more is more preferable. The content of the unit derived from -2-hydroxyethyl acrylate is preferably 50% by mass or less, more preferably 45% by mass or less, based on the total mass of the acrylic copolymer. It is more preferably 40% by mass or less. By setting the content of the unit derived from -2-hydroxyethyl acrylate in the acrylic copolymer within the above range, the interfacial adhesive strength between the acrylic pressure-sensitive adhesive layer and the silicone-based pressure-sensitive adhesive layer can be effectively enhanced. This makes it possible to improve the reworkability of the double-sided adhesive sheet.

The acrylic copolymer contained in the acrylic pressure-sensitive adhesive layer preferably further contains a unit derived from -2-methoxyethyl acrylate in addition to a unit derived from butyl acrylate. In this case, the content of the unit derived from -2-methoxyethyl acrylate is preferably 10% by mass or more, more preferably 15% by mass or more, based on the total mass of the acrylic copolymer. , 20% by mass or more is more preferable. The content of the unit derived from -2-methoxyethyl acrylate is preferably 50% by mass or less, more preferably 45% by mass or less, based on the total mass of the acrylic copolymer. It is more preferably 40% by mass or less. By setting the content of the unit derived from -2-methoxyethyl acrylic acid in the acrylic copolymer within the above range, the interfacial adhesive strength between the acrylic pressure-sensitive adhesive layer and the silicone-based pressure-sensitive adhesive layer can be effectively enhanced. This makes it possible to improve the reworkability of the double-sided adhesive sheet.

The acrylic copolymer contained in the acrylic pressure-sensitive adhesive layer is derived from a unit derived from -2-hydroxyethyl acrylate or a unit derived from -2-methoxyethyl acrylate, in addition to the unit derived from butyl acrylate. The acrylic copolymer preferably has one of the units to be used, in addition to the unit derived from butyl acrylate, the unit derived from -2-hydroxyethyl acrylate, and the acrylic acid-2. -May have both units derived from methoxyethyl.

The acrylic copolymer contained in the acrylic pressure-sensitive adhesive layer may further contain a unit derived from another acrylic monomer. Examples of other acrylic monomers include alkyl (meth) acrylates other than the above-mentioned acrylic monomers. Examples of the alkyl (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, lauryl (meth) acrylate, and -2 acrylate (meth) acrylate. -Ethylhexyl and the like can be mentioned. Above all, the acrylic copolymer preferably contains a unit derived from -2-ethylhexyl acrylate. The content of the unit derived from the alkyl (meth) acrylate is preferably 1% by mass or more, more preferably 5% by mass or more, and 10% by mass or more, based on the total mass of the acrylic copolymer. Is more preferable. The content of the unit derived from the alkyl (meth) acrylate is preferably 80% by mass or less, more preferably 70% by mass or less, based on the total mass of the acrylic copolymer.

The acrylic copolymer contained in the acrylic pressure-sensitive adhesive layer may contain a unit derived from an acrylic monomer having a crosslinkable functional group as another acrylic monomer. Examples of the crosslinkable functional group include a carboxy group, an amino group, an amide group, a glycidyl group, an isocyanate group and the like, and among them, the crosslinkable functional group is preferably a carboxy group. That is, the acrylic copolymer preferably contains a unit derived from acrylic acid.

As described above, the acrylic copolymer contained in the acrylic pressure-sensitive adhesive layer preferably further contains at least one selected from a unit derived from -2-ethylhexyl acrylic acid and a unit derived from acrylic acid. It is more preferable to further contain both the unit derived from acrylic acid-2-ethylhexyl and the unit derived from acrylic acid.

The acrylic copolymer may have other monomer units, if necessary. The other monomer may be any copolymerizable with the above-mentioned acrylic monomer, and examples thereof include (meth) acrylonitrile, vinyl acetate, styrene, vinyl chloride, vinylpyrrolidone, and vinylpyridine.

Further, the acrylic copolymer may further contain a unit derived from the nitrogen-containing monomer. Examples of the nitrogen-containing monomer include acryloylmorpholine, urethane acrylate, (meth) acrylamide, allylamide, dimethylacrylamide, diethylacrylamide, dimethylaminopropylacrylamide, diacetoneacrylamide and the like. The content of the unit derived from the nitrogen-containing monomer is preferably 20% by mass or less, and more preferably 10% by mass or less, based on the total mass of the acrylic copolymer.

The weight average molecular weight (Mw) of the acrylic copolymer is preferably 200,000 or more and 2.5 million or less, and more preferably 300,000 or more and 2 million or less. The weight average molecular weight (Mw) is calculated based on a calibration curve prepared by using a polystyrene standard material by gel permeation chromatography (GPC) measurement.

The measurement conditions of gel permeation chromatography (GPC) are as follows.
Solvent: Tetrahydrofuran Column: Shodex KF801, KF803L, KF806L (Three from Showa Denko KK were connected and used)
Column temperature: 40 ° C
Sample concentration: 0.5% by mass
Detector: RI-2031plus (manufactured by JASCO)
Pump: RI-2080plus (manufactured by JASCO)
Flow rate (flow velocity): 0.8 ml / min
Injection volume: 10 μl
Calibration curve: Standard polystyrene Shodex standard polystyrene (manufactured by Showa Denko KK) A calibration curve with 10 samples from Mw = 1320 to 2,500,000 was used.

The acrylic pressure-sensitive adhesive layer may contain a silane coupling agent. When the acrylic pressure-sensitive adhesive layer contains a silane coupling agent, the interfacial adhesive strength between the acrylic-based pressure-sensitive adhesive layer and the silicone-based pressure-sensitive adhesive layer can be more effectively enhanced. Examples of the silane coupling agent include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 2- (3,4-epoxycyclohexyl). Epyl group-containing silane coupling agent such as ethyltrimethoxysilane; 3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl-N- (1, Amino group-containing silane coupling agent such as 3-dimethylbutylidene) propylamine, N-phenyl-γ-aminopropyltrimethoxysilane; (3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, etc. Meta) Acrylic group-containing silane coupling agent; isocyanate group-containing silane coupling agent such as 3-isocyanuppropyltriethoxysilane; and the like. Above all, the silane coupling agent is preferably an epoxy group-containing silane coupling agent.

Further, as the silane coupling agent, one having a plurality of alkoxysilyl groups in the molecule can also be used. Examples of such a silane coupling agent include X-41-1053, X-41-1059A, X-41-1056, X-41-1805, X-41-1818, X manufactured by Shin-Etsu Chemical Co., Ltd. 4-118110, X-40-2651 and the like can be mentioned.

The content of the silane coupling agent is preferably 0.03% by mass or more and 5% by mass or less with respect to the total mass of the acrylic pressure-sensitive adhesive layer. The content of the silane coupling agent is preferably 0.06% by mass or more and 1% by mass or less with respect to the total mass of the acrylic pressure-sensitive adhesive layer. The silane coupling agent may be used alone or in combination of two or more.

The acrylic pressure-sensitive adhesive layer may contain a cross-linking agent. That is, the acrylic pressure-sensitive adhesive composition forming the acrylic pressure-sensitive adhesive layer preferably contains a cross-linking agent, whereby the cross-linking reaction of the above-mentioned cross-linking acrylic monomer can be promoted. Examples of the cross-linking agent include cross-linking possessed by the cross-linking acrylic copolymer from among known cross-linking agents such as isocyanate compounds, epoxy compounds, oxazoline compounds, aziridine compounds, metal chelate compounds, butylated melamine compounds and polyfunctional acrylates. It can be appropriately selected in consideration of the reactivity with the sex functional group. The cross-linking method can be selected from known methods such as thermal cross-linking and ionizing radiation cross-linking. Further, after the pressure-sensitive adhesive layer is formed, a curing treatment may be performed in an environment of 23 ° C. or the like in order to further increase the degree of cross-linking.

Examples of the isocyanate compound include tolylene diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate and the like. The diicyanate may be used as it is bifunctional, or may be used as a trifunctional derivative such as adduct, nurate, or burette.
Examples of the epoxy compound include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, glycerin diglycidyl ether, neopentyl glycol diglycidyl ether, and 1,6-hexanediol di. Glycyzyl ether, tetraglycidyl xylenediamine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, trimethylolpropane polyglycidyl ether, diglycerol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitol polyglycidyl ether, etc. Can be mentioned.

As the cross-linking agent, one type may be used alone or two or more types may be used in combination. The content of the cross-linking agent is preferably 0.01 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the acrylic copolymer.

The acrylic pressure-sensitive adhesive layer may contain a hydrogen-drawing type polymerization initiator. The hydrogen abstraction type polymerization initiator is particularly preferably a photopolymerization initiator. Examples of the hydrogen abstraction type photopolymerization initiator include benzophenone, benzoylbenzoic acid, methyl benzoylbenzoate, 4-phenylbenzophenone, hydroxybenzophenone, 3,3'-dimethyl-4-methoxybenzophenone, 2,4,6-trimethyl. Benzophenone, 4-methylbenzophenone, thioxanson, 2-chlorthioxanson, 2-methylthioxanson, 2,4-dimethylthioxanson, isopropylthioxanson, camphorquinone, dibenzosverone, 2-ethylanthraquinone, 3 , 3', 4,4'-tetra (t-butylperoxycarbonyl) benzophenone, benzyl, 9,10-phenanthlenquinone and the like. Above all, the hydrogen abstraction type photopolymerization initiator preferably contains at least one selected from benzophenone, 4-methylbenzophenone and 2,4,6-trimethylbenzophenone. Examples of these commercially available products include Irgacure MBF, SpeedcureMBP, SpeedcureTZT, SpeedcureMBF, SpeedcureITX, SpeedcureDETX, SpeedcureCPTX, SpeedcureMBB, and SpeedcurePBZ.
The content of the hydrogen abstraction type polymerization initiator is preferably 0.05% by mass or more and 10% by mass or less with respect to the total mass of the acrylic pressure-sensitive adhesive layer.

The acrylic pressure-sensitive adhesive layer may be a plasticizer, an antioxidant, a metal corrosion inhibitor, a pressure-sensitive adhesive, an ultraviolet absorber, an antioxidant, a photopolymerization initiator, a light stabilizer such as a hindered amine-based compound, etc., as required. Additives can be selected and blended as needed.
As the plasticizer, for example, a non-functional acrylic copolymer can be used. The non-functional acrylic copolymer is 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 and a functional group. It means a polymer composed of non-acrylic monomer units.
Examples of the antioxidant include a phenol-based antioxidant, an amine-based antioxidant, a lactone-based antioxidant, a phosphorus-based antioxidant, a sulfur-based antioxidant, and the like. One type of these antioxidants may be used alone, or two or more types may be used in combination.
Examples of the metal corrosion inhibitor include benzodiazole-based resins.
Examples of the tackifier include rosin-based resin, terpene-based resin, terpene phenol-based resin, Kumaron inden-based resin, styrene-based resin, xylene-based resin, phenol-based resin, petroleum resin and the like.
Examples of the ultraviolet absorber include benzotriazole-based compounds and benzophenone-based compounds.

Further, in order to prevent the acrylic pressure-sensitive adhesive layer from deteriorating over time, it is preferable to add an antiaging agent. By adding an anti-aging agent, it is possible to prevent a decrease in adhesive strength due to deterioration of the double-sided adhesive sheet. Examples of the anti-aging agent include general phenol-based antioxidants, phosphorus-based antioxidants, ultraviolet antioxidants, HALS (hindered amine-based stabilizers) and the like.

The acrylic pressure-sensitive adhesive composition forming the acrylic pressure-sensitive adhesive layer may contain a solvent. The solvent evaporates when the pressure-sensitive adhesive layer is formed, but the acrylic pressure-sensitive adhesive layer may contain a residual solvent.

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 and diacetone alcohol; ethers such as diethyl ether, diisopropyl ether, dioxane and tetrahydrofuran; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, isophorone and cyclohexanone; methyl acetate , Ethyl acetate, butyl acetate, isobutyl acetate, amyl acetate, ethyl butyrate and other esters; 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.

<Silicone adhesive layer>
The double-sided pressure-sensitive adhesive sheet of the present invention contains a silicone-based pressure-sensitive adhesive layer. The silicone-based pressure-sensitive adhesive layer is a layer containing a silicone-based resin (silicone-based pressure-sensitive adhesive) as a main component. Specifically, the content of the silicone-based resin in the silicone-based pressure-sensitive adhesive layer is preferably 50% by mass or more, more preferably 60% by mass or more, based on the total mass of the silicone-based pressure-sensitive adhesive layer. , 70% by mass or more, more preferably 80% by mass or more, and particularly preferably 90% by mass or more.

Examples of the silicone-based resin include silicone-based resins having a polysiloxane skeleton. Examples of the silicone-based resin include an addition reaction type, a condensation reaction type, an ultraviolet curable type, and an electron beam curable type. Among them, the addition reaction type silicone resin is preferably used because it has high reactivity and excellent productivity. As the addition reaction type silicone resin, for example, an organopoly having two or more alkenyl groups having 2 to 10 carbon atoms such as a vinyl group, an allyl group, a propenyl group, and a hexenyl group at the terminal and / or side chain of the molecule. Examples include siloxane.

When using an addition reaction type silicone resin, it is preferable to use a cross-linking agent and a catalyst in combination. Examples of the cross-linking agent include organopolysiloxane having a hydrogen atom bonded to at least two silicon atoms in one molecule. Specifically, dimethylhydrogensiloxy group-terminated closure dimethylsiloxane-methylhydrogensiloxane copolymer, trimethylsiloxy group-terminated closure dimethylsiloxane-methylhydrogensiloxane copolymer, trimethylsiloxy group-terminated closure methylhydrogenpolysiloxane, Examples include poly (hydrogencil sesquioxane).
Further, as the catalyst, fine particle platinum, fine particle platinum adsorbed on a carbon powder carrier, platinum chloride acid, alcohol-modified platinum chloride acid, olefin complex of platinum chloride acid, white metal compounds such as palladium and rhodium, etc. are used. Can be mentioned.

The silicone-based pressure-sensitive adhesive layer may be selected from among additives such as antioxidants, metal corrosion inhibitors, tackifiers, ultraviolet absorbers, hindered amine-based compounds, antistatic agents, and light stabilizers, if necessary. Can be selectively blended.
Examples of the antioxidant include a phenol-based antioxidant, an amine-based antioxidant, a lactone-based antioxidant, a phosphorus-based antioxidant, a sulfur-based antioxidant, and the like. One type of these antioxidants may be used alone, or two or more types may be used in combination.
Examples of the metal corrosion inhibitor include benzodiazole-based resins.
Examples of the tackifier include rosin-based resin, terpene-based resin, terpene phenol-based resin, Kumaron inden-based resin, styrene-based resin, xylene-based resin, phenol-based resin, petroleum resin and the like.
Examples of the ultraviolet absorber include benzotriazole-based compounds and benzophenone-based compounds.

Further, in order to prevent the silicone-based pressure-sensitive adhesive layer from deteriorating over time, it is preferable to add an anti-aging agent. By adding an anti-aging agent, it is possible to prevent a decrease in adhesive strength due to deterioration of the double-sided adhesive sheet. Examples of the anti-aging agent include general phenol-based antioxidants, phosphorus-based antioxidants, ultraviolet antioxidants, HALS (hindered amine-based stabilizers) and the like.

The silicone-based pressure-sensitive adhesive composition forming the silicone-based pressure-sensitive adhesive layer may contain a solvent. The solvent evaporates when the pressure-sensitive adhesive layer is formed, but the silicone-based pressure-sensitive adhesive layer may contain a residual solvent. Examples of the solvent include the same solvents that can be contained in the acrylic pressure-sensitive adhesive composition.

As the silicone-based adhesive, a commercially available product can be used. Examples of such silicone-based adhesives include KR-3704 and X40-3306 manufactured by Shin-Etsu Chemical Co., Ltd., DC7651ADHESIVE and SD7587LPSA manufactured by Toray Dow Corning Co., Ltd., and SE9500 manufactured by Aica Kogyo Co., Ltd. SE9600 and the like can be mentioned.

(Manufacturing method of double-sided adhesive sheet)
The manufacturing process of the double-sided pressure-sensitive adhesive sheet of the present invention preferably includes a step of laminating an acrylic pressure-sensitive adhesive layer and a silicone-based pressure-sensitive adhesive layer. Each pressure-sensitive adhesive layer is preferably a pressure-sensitive adhesive layer (adhesive sheet) formed by coating, and more preferably a pressure-sensitive adhesive layer (pressure-sensitive adhesive sheet) formed by sequential coating. In addition, in this specification, sequential coating means that each pressure-sensitive adhesive layer is coated in each step to form a separate sheet.

As a method for producing a double-sided pressure-sensitive adhesive sheet, for example, a step of applying an acrylic pressure-sensitive adhesive composition on a release sheet to form an acrylic pressure-sensitive adhesive layer and a silicone-based pressure-sensitive adhesive composition on another release sheet. Includes the steps of coating to form a silicone-based pressure-sensitive adhesive layer. Then, the step of stacking the acrylic pressure-sensitive adhesive layer and the silicone-based pressure-sensitive adhesive layer so as to be in direct contact with each other and crimping them is included.

The coating of each pressure-sensitive adhesive composition can be carried out using a known coating apparatus. 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.
Further, it is preferable to provide a drying step after coating, and the drying step can be carried out by using a known heating device such as a heating furnace or an infrared lamp.

The manufacturing step of the double-sided pressure-sensitive adhesive sheet preferably includes a surface activation treatment step before superimposing the acrylic pressure-sensitive adhesive layer and the silicone-based pressure-sensitive adhesive layer. Here, examples of the surface activation treatment include corona treatment and plasma treatment. Above all, as the surface activation treatment, it is preferable to perform a corona treatment.

In the surface activation treatment step, it is preferable that at least one of the acrylic pressure-sensitive adhesive layer and the silicone-based pressure-sensitive adhesive layer is subjected to the surface activation treatment. Here, it is preferable that the surface activation treatment is applied to the surface of each pressure-sensitive adhesive layer on the bonding surface side. That is, at least one selected from the surface on the interface side of the acrylic pressure-sensitive adhesive layer and the surface on the interface side of the silicone-based pressure-sensitive adhesive layer is preferably a surface activation-treated surface. Above all, it is particularly preferable that the surface of the silicone-based pressure-sensitive adhesive layer on the interface side is the surface activation-treated surface. It is also preferable that both the acrylic pressure-sensitive adhesive layer and the silicone-based pressure-sensitive adhesive layer are subjected to surface activation treatment.

When the surface of the acrylic pressure-sensitive adhesive layer on the interface side is a surface-activated surface, the wet tension of the surface-activated surface is preferably 70 mN / m or more, more preferably 73 mN / m or more. .. The upper limit of the wetting tension of the surface activated surface is not particularly limited. Further, the wet tension of the acrylic pressure-sensitive adhesive layer after the surface activation treatment is preferably 1.1 times or more the wet tension of the acrylic pressure-sensitive adhesive layer before the surface activation treatment.

When the surface of the silicone-based pressure-sensitive adhesive layer on the interface side is a surface-activated surface, the wet tension of the surface-activated surface is preferably 30 mN / m or more, more preferably 35 mN / m or more. .. The upper limit of the wetting tension of the surface activated surface is not particularly limited, but is preferably 50 mN / m, for example, in order to prevent a decrease in transparency. The wetting tension is measured by applying a wetting instruction standard solution (manufactured by Wako Pure Chemical Industries, Ltd.) to the surface of the adhesive layer according to JIS K 6768 1999. When the surface activation treatment is applied only to either the acrylic pressure-sensitive adhesive layer or the silicone-based pressure-sensitive adhesive layer, it is preferable that the surface activation treatment is applied to the silicone-based pressure-sensitive adhesive layer.

Examples of the corona treatment include a method of discharging in normal pressure air using a corona treatment machine. The corona output in the corona treatment is not particularly limited, but is preferably, for example, 0.5 kW or more and 8.0 kW or less, more preferably 0.5 kW or more and 7.0 kW or less, and 0.5 kW or less. It is more preferably 6.0 kW or less. The processing speed in the corona treatment is preferably 5 m / min or more and 100 m / min or less, more preferably 5 m / min or more and 90 m / min or less, and further preferably 5 m / min or more and 80 m / min or less. ..

Examples of the plasma treatment include a method of discharging in normal pressure air by a plasma discharger. The plasma output in the plasma processing is not particularly limited, but is preferably 0.5 kW or more and 5.0 kW or less, more preferably 0.5 kW or more and 3.0 kW or less, and 0.5 kW or less, for example. It is more preferably 1.5 kW or less. The processing speed in the plasma treatment is preferably 5 m / min or more and 100 m / min or less, more preferably 5 m / min or more and 90 m / min or less, and further preferably 5 m / min or more and 80 m / min or less. ..

The degree of surface activation is preferably adjusted appropriately so that the wetting tension is within the above-mentioned range.

The crimping method in the step of crimping the acrylic pressure-sensitive adhesive layer and the silicone-based pressure-sensitive adhesive layer is not particularly limited, but it is preferable to use a roll bonding machine capable of continuous crimping.

(Double-sided adhesive sheet with release sheet)
It is preferable that the release sheet is laminated on at least one surface of the double-sided pressure-sensitive adhesive sheet, and it is more preferable that the release sheet is laminated on both sides of the double-sided pressure-sensitive adhesive sheet. That is, the double-sided pressure-sensitive adhesive sheet of the present invention is preferably a double-sided pressure-sensitive adhesive sheet with a release sheet provided with release sheets on both sides of the double-sided pressure-sensitive adhesive sheet.

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

When laminating the release sheets on both sides of the double-sided adhesive sheet, it is preferable that the two release sheets (the first release sheet and the second release sheet) have different release forces. Above all, the one in which the peeling force of the first peeling sheet (the peeling sheet on the acrylic pressure-sensitive adhesive layer side) is smaller than the peeling force of the second peeling sheet (the peeling sheet on the silicone-based pressure-sensitive adhesive layer side) is in the processing process. More preferred. By laminating the peeling sheets having different peeling forces in this way, it is possible to suppress the crying phenomenon in which the adhesive sheet is lifted from the peeling sheet on the heavy peeling force side when the peeling sheet on the light peeling force side is peeled off. ..

The first release sheet (release sheet on the acrylic pressure-sensitive adhesive layer side) is preferably a release sheet on the light release force side, and the release force when the first release sheet is peeled from the acrylic pressure-sensitive adhesive layer is , 0.01 N / 50 mm or more, and more preferably 0.1 N / 50 mm or more. Further, the peeling force when peeling the first peeling sheet from the acrylic pressure-sensitive adhesive layer is preferably 1.0 N / 50 mm or less, more preferably 0.8 N / 50 mm or less, and more preferably 0.6 N. It is more preferably / 50 mm or less.

The second release sheet (the release sheet on the silicone-based pressure-sensitive adhesive layer side) is preferably a release sheet on the heavy peeling force side, and the release force when peeling the second release sheet from the silicone-based pressure-sensitive adhesive layer is , 0.5N / 50mm or more, and more preferably 0.6N / 50mm or more. The peeling force when peeling the second release sheet from the silicone-based pressure-sensitive adhesive layer is preferably 10.0 N / 50 mm or less, more preferably 5.0 N / 50 mm or less, and more preferably 3.0 N. It is more preferably / 50 mm or less.

The peeling force of the second release sheet (the release sheet on the silicone adhesive layer side) was R _H , and the release force of the first release sheet (the release sheet on the acrylic adhesive layer side) was _RL . In this case, the value of _RH / _RL is preferably 1.5 or more, and more preferably 2.0 or more.

(Double-sided adhesive sheet for bonding optical members)
The double-sided adhesive sheet of the present invention is preferably used for bonding various members. Although the use for bonding is not limited, the double-sided pressure-sensitive adhesive sheet of the present invention is preferably a double-sided pressure-sensitive adhesive sheet for bonding optical members. Examples of the optical member include a liquid crystal display or a touch panel. In particular, the double-sided adhesive sheet of the present invention is preferably used for bonding glass and a liquid crystal display or glass and a touch panel.

(Laminated body)
The present invention may relate to a laminate having the above-mentioned double-sided pressure-sensitive adhesive sheet and an adherend. In this case, the laminate is a laminate in which the surface to be attached to the first adherend is an acrylic pressure-sensitive adhesive layer and the surface to be attached to the second adherend is a silicone-based adhesive layer. Is preferable. Above all, it is preferable that the first adherend is glass. With such a configuration, it is easy to re-peel from the second adherend while firmly adhering to the first adherend.

Hereinafter, 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 limiting by the specific examples shown below.

[Example 1]
<Preparation of acrylic pressure-sensitive adhesive composition>
An acrylic copolymer was prepared by copolymerizing 40 parts by mass of n-butyl acrylate, 55 parts by mass of -2-ethylhexyl acrylate, and 5 parts by mass of acrylic acid. The weight average molecular weight of this acrylic copolymer was 1 million.

100 parts by mass of the obtained acrylic copolymer, 0.05 part by mass of 1,3-bis (N, N'-diglycidylaminomethyl) cyclohexane (manufactured by Mitsubishi Gas Chemicals, TERAD-C) as an epoxy-based cross-linking agent. As a silane coupling agent, 0.15 parts by mass of a silicone alkoxy oligomer (X-41-1810 manufactured by Shin-Etsu Chemical Co., Ltd.) is mixed, and the mixture is sufficiently stirred to make the solid content concentration 40% by mass. The acrylic pressure-sensitive adhesive composition (A) was obtained by diluting with ethyl.

<Preparation of silicone-based adhesive composition>
100 parts by mass (solid content conversion value; the same applies hereinafter) of an additive-type organopolysiloxane (KS-847H, manufactured by Shin-Etsu Chemical Industry Co., Ltd.) consisting of an organopolysiloxane having a vinyl group and an organopolysiloxane having a siloxane bond as the main skeleton. ), 20 parts by mass of organopolysiloxane (silicone resin; SD-4584, manufactured by Tohredo Corning Co., Ltd.) containing a trifunctional or tetrafunctional siloxane unit, platinum catalyst (manufactured by Tohoku Redow Corning Co., Ltd., SRX-212) 1. A silicone-based pressure-sensitive adhesive composition was obtained by mixing 5 parts by mass, stirring sufficiently, and diluting with methyl ethyl ketone so that the solid content concentration became 40% by mass.

<Making a double-sided adhesive sheet>
(Preparation of acrylic adhesive layer)
A 38 μm-thick polyethylene terephthalate film (separator film) provided with a release agent layer treated with an acrylic pressure-sensitive adhesive composition (A) (manufactured by Oji F-Tex Co., Ltd., 38RL-07 (2)). The first release sheet is attached to one side by uniformly applying the surface of the film with an applicator so that the coating amount after drying is 50 μm, and drying in an air circulation type constant temperature oven at 100 ° C. for 3 minutes. An acrylic pressure-sensitive adhesive layer was obtained. The pressure-sensitive adhesive layer to which the first release sheet was attached to one side was cured in an environment of 23 ° C. and a relative humidity of 50% for 7 days.

(Preparation of silicone adhesive layer)
The silicone-based adhesive composition is uniformly applied to the surface of a 38 μm-thick polyethylene terephthalate film (Toray Industries, Inc., Lumirror S-10 # 38) with an applicator so that the amount of application after drying is 50 μm. , A silicone-based pressure-sensitive adhesive layer having a second release sheet attached to one side was obtained by drying in an air circulation type constant temperature oven at 100 ° C. for 3 minutes.

(Surface activation treatment)
The surface of the silicone-based pressure-sensitive adhesive layer was subjected to a corona discharge treatment. The corona discharge treatment was performed using a corona surface treatment device manufactured by Kasuga Electric. The corona discharge treatment was performed under the condition that the wetting tension of the silicone-based pressure-sensitive adhesive layer was 30 mN / m or more.

(Making a double-sided adhesive sheet with a release sheet)
By adhering the surface-activated surface of the silicone-based pressure-sensitive adhesive layer to the acrylic-based pressure-sensitive adhesive layer, the first release sheet / acrylic-based pressure-sensitive adhesive layer / silicone-based pressure-sensitive adhesive layer / first A double-sided adhesive sheet with a release sheet in which the release sheets of No. 2 were laminated in this order was obtained.

[Example 2]
Except for preparing an acrylic copolymer by copolymerizing 40 parts by mass of n-butyl acrylate, 30 parts by mass of -2-hydroxyethyl acrylate, 25 parts by mass of -2-ethylhexyl acrylate, and 5 parts by mass of acrylic acid. Obtained a double-sided adhesive sheet with a release sheet in the same manner as in Example 1. The weight average molecular weight of the obtained acrylic copolymer was 1.5 million.

[Example 3]
Except for preparing an acrylic copolymer by copolymerizing 40 parts by mass of n-butyl acrylate, 30 parts by mass of -2-methoxyethyl acrylate, 25 parts by mass of -2-ethylhexyl acrylate, and 5 parts by mass of acrylic acid. Obtained a double-sided adhesive sheet with a release sheet in the same manner as in Example 1. The weight average molecular weight of the obtained acrylic copolymer was 1.5 million.

[Example 4]
A double-sided pressure-sensitive adhesive sheet with a release sheet was obtained in the same manner as in Example 1 except that the surface activation treatment applied to the silicone-based pressure-sensitive adhesive layer was changed from the corona discharge treatment to the plasma discharge treatment. The plasma discharge treatment was performed under the condition that the wetting tension of the silicone-based pressure-sensitive adhesive layer was 30 mN / m or more.

[Comparative Example 1]
Both sides with a release sheet were obtained in the same manner as in Example 1 except that an acrylic copolymer was prepared by copolymerizing 55 parts by mass of -2-ethylhexyl acrylate, 40 parts by mass of methyl methacrylate, and 5 parts by mass of acrylic acid. Obtained an adhesive sheet. The weight average molecular weight of the obtained acrylic copolymer was 500,000.

[Comparative Example 2]
Examples except that an acrylic copolymer was prepared by copolymerizing 10 parts by mass of n-butyl acrylate, 55 parts by mass of -2-ethylhexyl acrylate, 30 parts by mass of methyl methacrylate, and 5 parts by mass of acrylic acid. A double-sided adhesive sheet with a release sheet was obtained in the same manner as in 1. The weight average molecular weight of the obtained acrylic copolymer was 1 million.

(Measurement and evaluation)
<Measurement of adhesive strength>
(Adhesive strength of acrylic adhesive layer)
Polyethylene terephthalate film with an easy adhesive layer (Toyobo, A4300 # 100) on the adhesive surface of the acrylic adhesive layer to which the first release sheet is attached to one side obtained by the production of (Preparation of acrylic adhesive layer). ) Was attached as a backing base material. The first release sheet was peeled off, and the adhesive surface of the acrylic adhesive layer was attached to soda glass. Twenty-four hours after the application, the adhesive strength was measured under the conditions of a peeling speed of 300 mm / min and a peeling angle of 180 ° according to Method 1 of JIS Z 0237.

(Adhesive strength of silicone adhesive layer)
The first release sheet of the double-sided adhesive sheet with a release sheet in which the first release sheet / acrylic pressure-sensitive adhesive layer / silicone-based pressure-sensitive adhesive layer / second release sheet is laminated in this order is peeled off, and an easy-adhesive layer is attached. A polyethylene terephthalate film (Toyobo Co., Ltd., A4300 # 100) was attached as a backing base material. The second release sheet was peeled off, and the adhesive surface of the silicone-based adhesive layer was attached to soda glass. Twenty-four hours after the application, the adhesive strength was measured under the conditions of a peeling speed of 300 mm / min and a peeling angle of 180 ° according to Method 1 of JIS Z 0237.

<Wet tension>
The wetting tension was measured by applying a wetting instruction standard solution (manufactured by Wako Pure Chemical Industries, Ltd.) to the surface of the adhesive layer according to JIS K 6768 1999.

<Interfacial adhesive strength>
[Making an adhesive tape with a base material for lining]
An acrylic copolymer was prepared by copolymerizing 90 parts by mass of n-butyl acrylate and 10 parts by mass of acrylic acid. The weight average molecular weight of this acrylic copolymer was 500,000.
100 parts by mass of the obtained acrylic copolymer, 0.05 part by mass of 1,3-bis (N, N'-diglycidylaminomethyl) cyclohexane (manufactured by Mitsubishi Gas Chemicals, TERAD-C) as an epoxy-based cross-linking agent. Mix 5 parts by mass of a silicone epoxy oligomer (X-41-1810 manufactured by Shin-Etsu Chemical Co., Ltd.) as a silane coupling agent, stir well, and use ethyl acetate so that the solid content concentration becomes 40% by mass. By diluting, an acrylic pressure-sensitive adhesive composition for a pressure-sensitive adhesive tape with a base material for lining was obtained.
The obtained acrylic pressure-sensitive adhesive composition was uniformly applied to the surface of a polyethylene terephthalate film with an easy-adhesive layer (A4300 # 100 manufactured by Toyobo Co., Ltd.) with an applicator so that the coating amount after drying was 25 μm. By drying in an air circulation type constant temperature oven at ° C. for 3 minutes, an adhesive tape with a base material for lining was obtained.
[Preparation of sample for measuring interfacial adhesive strength]
The "first release sheet" of the "first release sheet / acrylic pressure-sensitive adhesive layer / silicone-based pressure-sensitive adhesive layer / second release sheet" obtained in Examples and Comparative Examples was peeled off and applied to the acrylic pressure-sensitive adhesive layer surface. "Polyethylene terephthalate film with easy adhesive layer (A4300 # 100 manufactured by Toyobo)" was attached. The "second release sheet" of the "polyethylene terephthalate film with easy-adhesive layer / acrylic pressure-sensitive adhesive layer / silicone-based pressure-sensitive adhesive layer / second release sheet" thus obtained is peeled off, and the wetting tension is increased. The surface of the silicone-based adhesive layer was surface-activated using a Corona surface treatment device manufactured by Kasuga Electric Co., Ltd. so as to have a temperature of 34 mN / m or more. Further, surface activation treatment was performed using a corona surface treatment device manufactured by Kasuga Electric Co., Ltd. so that the wetting tension on the surface of the acrylic pressure-sensitive adhesive layer of the pressure-sensitive adhesive tape with a backing substrate was 73 mN / m or more.
Next, the surface-activated silicone-based pressure-sensitive adhesive layer surface of the "polyethylene terephthalate film with easy-adhesive layer / acrylic pressure-sensitive adhesive layer / silicone-based pressure-sensitive adhesive layer" was subjected to surface-activating treatment on the "lining base material". An interface having the structure of "polyethylene terephthalate film with easy adhesive layer / acrylic adhesive layer / silicone adhesive layer / adhesive tape with backing base material" by adhering the acrylic adhesive layer surface of "adhesive tape with adhesive". A sample for measuring adhesive strength was obtained.
[Measurement of interfacial adhesive strength]
24 hours after obtaining "polyethylene terephthalate film with easy adhesive layer / acrylic pressure-sensitive adhesive layer / silicone-based pressure-sensitive adhesive layer / pressure-sensitive adhesive tape with backing base material" as described above (silicone-based with surface activation treatment). 24 hours after the adhesive layer surface and the acrylic adhesive layer surface are attached), the adhesive tape side with the backing substrate is placed under the conditions of a peeling speed of 300 mm / min and a peeling angle of 180 ° according to Method 1 of JIS Z 0237. By peeling off, the adhesive strength at the interface of the "acrylic adhesive layer / silicone adhesive layer" was measured.

<Evaluation of reworkability>
A double-sided pressure-sensitive adhesive sheet with a release sheet in which the first release sheet / acrylic pressure-sensitive adhesive layer / silicone-based pressure-sensitive adhesive layer / second release sheet is laminated in this order is cut into a 25 × 50 mm square, and then the first release is performed. The sheet was peeled off, and a slide glass (manufactured by Matsunami Glass, S9112, size 76 × 52 mm) was attached to an acrylic adhesive layer (1 reciprocating 2 kg roller). Then, the second release sheet was peeled off, and the silicone-based pressure-sensitive adhesive layer was attached to soda glass (Matsunami Glass, S9112, size 76 × 52 mm). The double-sided adhesive sheet with a double-sided glass plate thus obtained was set in a universal tensile tester (Tencilon UTM-4-100 manufactured by Orientec), and the peeling speed was 300 mm / min and the peeling angle was in accordance with JIS Z 0237. The silicone-based pressure-sensitive adhesive layer was peeled off from the slide glass under the condition of 90 ° (peeling upward), and evaluated based on the following criteria.
"Excellent": After the silicone-based adhesive layer was attached to the slide glass, it was left in an environment of 40 ° C. and a relative humidity of 90% for 240 hours, and when it was peeled off thereafter, the adhesive layer did not remain on the surface of the slide glass.
"Good": After the silicone-based adhesive layer was attached to the slide glass, it was left in an environment of 40 ° C. and a relative humidity of 90% for 24 hours, and when it was peeled off thereafter, the adhesive layer did not remain on the surface of the slide glass. However, when the glass is left in an environment of 40 ° C. and a relative humidity of 90% for 240 hours and then peeled off, an adhesive layer remains on the surface of the slide glass.
"Yes": After the silicone-based adhesive layer was attached to the soda glass, it was left in an environment of 23 ° C. and a relative humidity of 50% for 30 minutes, and when it was peeled off after that, the adhesive layer did not remain on the surface of the slide glass. However, when the glass is left in an environment of 40 ° C. and a relative humidity of 90% for 24 hours and then peeled off, an adhesive layer remains on the surface of the slide glass.
"Impossible": After the silicone-based adhesive layer is attached to the soda glass, it is left for 30 minutes in an environment of 23 ° C. and a relative humidity of 50%, and when it is peeled off after that, the adhesive layer remains on the surface of the slide glass.

In the double-sided pressure-sensitive adhesive sheet obtained in Examples, the acrylic pressure-sensitive adhesive layer exhibited a strong adhesive force against glass, and the silicone-based pressure-sensitive adhesive layer was excellent in reworkability. On the other hand, in the double-sided pressure-sensitive adhesive sheet obtained in the comparative example, the pressure-sensitive adhesive layer remained on the adherend during rework.
In addition, the double-sided adhesive sheet obtained in the examples was excellent in curved surface followability and step followability.

10 Acrylic adhesive layer 12 Silicone adhesive layer 100 Double-sided adhesive sheet

Claims (9)

Acrylic adhesive layer and
It has a silicone-based pressure-sensitive adhesive layer directly laminated on the acrylic-based pressure-sensitive adhesive layer, and has a silicone-based pressure-sensitive adhesive layer.
The acrylic pressure-sensitive adhesive layer has an acrylic copolymer containing a unit derived from butyl acrylate.
A double-sided pressure-sensitive adhesive sheet in which the content of the unit derived from butyl acrylate is 30% by mass or more with respect to the total mass of the acrylic copolymer. The acrylic copolymer further contains a unit derived from -2-hydroxyethyl acrylate, and the content of the unit derived from -2-hydroxyethyl acrylate is the total mass of the acrylic copolymer. The double-sided adhesive sheet according to claim 1, wherein the content is 10% by mass or more and 50% by mass or less. The acrylic copolymer further contains a unit derived from -2-methoxyethyl acrylate, and the content of the unit derived from -2-methoxyethyl acrylate is the total mass of the acrylic copolymer. The double-sided adhesive sheet according to claim 1, wherein the content is 10% by mass or more and 50% by mass or less. The double-sided pressure-sensitive adhesive sheet according to any one of claims 1 to 3, wherein the acrylic copolymer further contains at least one selected from a unit derived from -2-ethylhexyl acrylic acid and a unit derived from acrylic acid. .. The double-sided pressure-sensitive adhesive sheet according to any one of claims 1 to 4, wherein the interfacial adhesive strength between the acrylic pressure-sensitive adhesive layer and the silicone-based pressure-sensitive adhesive layer is 1 N / 25 mm or more. The double-sided pressure-sensitive adhesive sheet according to any one of claims 1 to 5, wherein the acrylic pressure-sensitive adhesive layer has an adhesive strength against glass of 1 N / 25 mm or more and 30 N / 25 mm or less. The double-sided pressure-sensitive adhesive sheet according to any one of claims 1 to 6, wherein the silicone-based pressure-sensitive adhesive layer has an adhesive strength against glass of 0.005 N / 25 mm or more and 1 N / 25 mm or less. The double-sided surface according to any one of claims 1 to 7, wherein the surface of the silicone-based pressure-sensitive adhesive layer on the interface side is a surface-activated surface, and the wet tension of the surface-activated surface is 30 mN / m or more. Adhesive sheet. A double-sided adhesive sheet with a release sheet provided with release sheets on both sides of the double-sided adhesive sheet according to any one of claims 1 to 8.

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