JP7310100B2 - Double-sided pressure-sensitive adhesive sheet with release sheet and method for producing double-sided pressure-sensitive adhesive sheet with release sheet - Google Patents

Description

TECHNICAL FIELD The present invention relates to a double-sided pressure-sensitive adhesive sheet with a release sheet and a method for producing a double-sided pressure-sensitive adhesive sheet with a release sheet.

2. Description of the Related Art In recent years, in various fields, display devices such as liquid crystal displays (LCDs) and image display devices combining display devices such as touch panels and input devices have been widely used. In these display devices and input devices, double-sided pressure-sensitive adhesive sheets are used for bonding optical members.

Double-sided pressure-sensitive adhesive sheets are sometimes used for bonding different types of adherends. In this case, the double-sided pressure-sensitive adhesive sheet is required to have an optimum adhesive strength according to the adhesive properties 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 with different pressure-sensitive adhesive properties.

In a display device or an input device, the surface 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 bonding the protective sheet to the display surface, the liquid crystal display is prevented from being cracked or damaged. 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 deterioration over time. For example, Patent Literature 3 discloses a double-sided pressure-sensitive adhesive sheet having at least two pressure-sensitive adhesive layers and configured to be removable from the display surface of a display device. In Examples of Patent Document 3, each PSA layer is formed from different types of acrylic polymers, and it is being studied to improve the durability and reworkability of the double-sided PSA sheet. The double-sided pressure-sensitive adhesive sheet of Patent Document 3 is intended for bonding between a display surface and a touch panel.

JP-A-5-17725 JP 2011-57883 A Japanese Patent Application Laid-Open No. 2004-231723

However, when the double-sided pressure-sensitive adhesive sheet in the prior art is re-peeled from the adherend, there is a problem that the pressure-sensitive adhesive remains on the adherend during reworking. If the adhesive remains on the adherend, the adhesive needs to be wiped off with a solvent or washed, which is a problem because rework takes time and effort. In particular, protective sheets that are laminated or reworked by general consumers who cannot use special equipment, jigs, or chemicals must be able to be easily reworked from the display surface. Adhesion must be extremely low. On the other hand, the double-faced pressure-sensitive adhesive sheet used as the protective sheet needs to firmly adhere to the adherend on the side opposite to the display surface. In general, it is difficult to laminate adhesive layers having such contradictory adhesive properties, so double-sided adhesive sheets with a base film provided between a slightly adhesive layer and a strong adhesive layer are used. there is However, double-sided PSA sheets with a base film between a low-adhesion layer and a strong-adhesion layer tend to increase in thickness, and cannot meet the recent demand for thinner films. I had a problem with not being able to do it.

For this reason, the present inventor proceeded with the development of a double-sided pressure-sensitive adhesive sheet in which a substrate film is not provided between the weakly adhesive layer and the strong adhesive layer. However, when release sheets are provided on both surfaces of such a double-sided pressure-sensitive adhesive sheet, since the release sheet on the side of the slightly adhesive layer is released first, it is difficult to release the release sheet on the side of the strong adhesive layer first. However, it was difficult to peel off the release sheet on the strong adhesive layer side first, attach the adherend to the strong adhesive layer side, and leave the release sheet on the weak adhesive layer side. In addition, it is possible to suppress the peelability of the release sheet on the side of the slightly adhesive layer by increasing the adhesive strength of the slightly adhesive layer. Air (bubbles) may be entrapped when the slightly adhesive layer is adhered to the adherend, which poses a problem.

Therefore, in order to solve the above problems, an object of the present invention is to provide a double-sided pressure-sensitive adhesive sheet with a release sheet that is excellent in workability of the double-sided pressure-sensitive adhesive sheet and has good air release properties on the slightly adhesive layer side. That is, the present invention provides a double-sided pressure-sensitive adhesive sheet with a release sheet that is easy to process because the release order of the release sheets is not limited (the release sheet on the side of the strong adhesive layer can be peeled off first), and the weak adhesive layer is added. To provide a double-faced pressure-sensitive adhesive sheet with a release sheet capable of suppressing entrainment of air because air is easily released when it is adhered to an adherend.

As a result of intensive studies to solve the above problems, the present inventors have found that a first release sheet, a first pressure-sensitive adhesive layer, a second pressure-sensitive adhesive layer and a second release sheet are laminated in this order. In the double-sided pressure-sensitive adhesive sheet with a release sheet, the peel force when peeling the second release sheet from the second release sheet with weak adhesion is measured by removing the first release sheet from the first pressure-sensitive adhesive layer with strong adhesion. It has been found that a double-sided pressure-sensitive adhesive sheet with a release sheet having excellent workability and good air release properties on the slightly adhesive layer side can be obtained by increasing the peel force at the time of peeling.
Specifically, the present invention has the following configurations.

[1] A double-sided pressure-sensitive adhesive sheet with a release sheet in which a first release sheet, a first pressure-sensitive adhesive layer, a second pressure-sensitive adhesive layer and a second release sheet are laminated in this order,
The second adhesive layer is directly laminated on the first adhesive layer,
The adhesive strength to glass of the first adhesive layer is 10 to 1000 times the adhesive strength to glass of the second adhesive layer,
Double-sided pressure-sensitive adhesive sheet with a release sheet, wherein the release force when peeling the second release sheet from the second pressure-sensitive adhesive layer is greater than the peel force when peeling the first release sheet from the first pressure-sensitive adhesive layer .
[2] The double-sided pressure-sensitive adhesive sheet with a release sheet according to [1], wherein the interfacial adhesive strength between the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer is 1 N/25 mm or more.
[3] The first adhesive layer has an adhesive strength to glass of 1 to 50 N/25 mm, and the second adhesive layer has an adhesive strength to glass of 0.01 to 1 N/25 mm [1] or [2] ] The double-sided pressure-sensitive adhesive sheet with a release sheet according to
[4] The double-sided pressure-sensitive adhesive with a release sheet according to any one of [1] to [3], wherein the first pressure-sensitive adhesive layer is an acrylic pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer is a silicone pressure-sensitive adhesive layer. sheet.
[5] The double-sided pressure-sensitive adhesive sheet with a release sheet according to any one of [1] to [4], wherein the first release sheet contains a silicone-based release agent.
[6] The double-sided pressure-sensitive adhesive sheet with a release sheet according to any one of [1] to [5], wherein the release load of the second release sheet is 70 to 20000 mN/50 mm.
[7] forming a first pressure-sensitive adhesive layer on a first release sheet and forming a second pressure-sensitive adhesive layer on a second release sheet;
A method for producing a double-sided pressure-sensitive adhesive sheet with a release sheet, comprising a step of laminating the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer so that they are in contact with each other,
The adhesive strength to glass of the first adhesive layer is 10 to 1000 times the adhesive strength to glass of the second adhesive layer,
A method for producing a double-sided pressure-sensitive adhesive sheet with a release sheet, wherein the release force of the second release sheet is greater than the release force of the first release sheet.

According to the present invention, it is possible to obtain a double-faced pressure-sensitive adhesive sheet with a release sheet which is excellent in processability and has good air release properties on the slightly adhesive layer side.

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

The present invention will be described in detail below. Although the constituent elements described below may be described based on representative embodiments and specific examples, the present invention is not limited to such embodiments.

(Double-sided adhesive sheet with release sheet)
The present invention relates to a double-sided pressure-sensitive adhesive sheet with a release sheet, in which a first release sheet, a first pressure-sensitive adhesive layer, a second pressure-sensitive adhesive layer and a second release sheet are laminated in this order. Here, the second adhesive layer is directly laminated on the first adhesive layer, and the adhesive strength of the first adhesive layer to glass is the adhesive strength of the second adhesive layer to glass. 10 to 1000 times. In addition, the peel force when peeling the second release sheet from the second pressure-sensitive adhesive layer is greater than the peel force when peeling the first release sheet from the first pressure-sensitive adhesive layer. The double-sided pressure-sensitive adhesive sheet composed of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer has a plurality of pressure-sensitive adhesive layers, so it can also be called a double-sided laminated pressure-sensitive adhesive sheet.

Since the double-sided pressure-sensitive adhesive sheet with a release sheet of the present invention has the above structure, it is excellent in workability. Here, the term "excellent processability" means that the release order of the release sheets is not restricted, that is, the release sheet on the side of the strong adhesive layer can be peeled off first. It means that it is easy to peel off at least one release sheet to produce various laminates. In the present invention, since the first release sheet attached to the strongly adhesive first pressure-sensitive adhesive layer is in a state where it is easy to peel off first, the first release sheet on the side of the first pressure-sensitive adhesive layer is used. is peeled off first, the adherend is attached to the first pressure-sensitive adhesive layer side, and the release sheet is left on the second pressure-sensitive adhesive layer side. For example, after peeling off the first release sheet on the first adhesive layer side first, the glass sheet is attached to the first adhesive layer side, and the glass sheet, the first adhesive layer, and the second adhesive layer are attached. A laminate in which the pressure-sensitive adhesive layer and the second release sheet are laminated in this order can be easily produced. Such a laminate is preferably used, for example, as a surface protective sheet for liquid crystal displays.

Further, when the second pressure-sensitive adhesive layer is attached to the adherend after peeling the second release sheet of the double-sided pressure-sensitive adhesive sheet with a release sheet of the present invention, the second pressure-sensitive adhesive layer and the adherend It is suppressed that air (bubbles) is caught between the That is, the second pressure-sensitive adhesive layer has excellent air release properties, and when the second pressure-sensitive adhesive layer is attached to the adherend, no air bubbles remain at the interface between the second pressure-sensitive adhesive layer and the adherend. . In the present invention, in order to increase the peel strength (enhance the adhesion) between the second adhesive layer and the second release sheet, the second release sheet is used instead of increasing the adhesive strength of the second adhesive layer. Since the peelability of the second pressure-sensitive adhesive layer is controlled, the air release property of the second pressure-sensitive adhesive layer is not impaired. That is, the present invention succeeds in reconciling the two contradictory properties of processability and air release property.

FIG. 1 is a cross-sectional view illustrating the configuration of the double-sided pressure-sensitive adhesive sheet with a release sheet of the present invention. The double-sided pressure-sensitive adhesive sheet 100 with a release sheet of the present invention has a first pressure-sensitive adhesive layer 10 and a second pressure-sensitive adhesive layer 12, and the first pressure-sensitive adhesive layer 10 is provided with a first release sheet. 20 is laminated, and a second release sheet 22 is laminated on the second adhesive layer 12 side.

In this specification, the first pressure-sensitive adhesive layer 10 and the second pressure-sensitive adhesive layer 12 are referred to as a double-sided pressure-sensitive adhesive sheet. As shown in FIG. 1, the double-sided pressure-sensitive adhesive sheet 50 preferably has a structure in which the first pressure-sensitive adhesive layer 10 and the second pressure-sensitive adhesive layer 12 are laminated one by one. There may be. For example, the first pressure-sensitive adhesive layer 10 shown as a one-layer structure in FIG. It may consist of a lamination structure of the above adhesive layers. Also, the double-sided pressure-sensitive adhesive sheet 50 is a double-sided pressure-sensitive adhesive sheet that does not have a support (substrate) as shown in FIG. Therefore, in the double-sided pressure-sensitive adhesive sheet 50, the first pressure-sensitive adhesive layer 10 and the second pressure-sensitive adhesive layer 12 are laminated in direct contact with each other. Therefore, the double-sided pressure-sensitive adhesive sheet can be made thinner as necessary.

The adhesive strength to glass of the first pressure-sensitive adhesive layer constituting the double-sided pressure-sensitive adhesive sheet with a release sheet of the present invention may be at least 10 times, and at least 50 times, that of the second pressure-sensitive adhesive layer to glass. is preferred, and 100 times or more is more preferred. The adhesive strength of the first pressure-sensitive adhesive layer to glass may be 1000 times or less that of the second pressure-sensitive adhesive layer to glass, more preferably 600 times or less. Thus, it can be said that the first pressure-sensitive adhesive layer is a strong pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer is a weak pressure-sensitive adhesive layer. By setting the adhesive strength of the first adhesive layer to glass and the adhesive strength of the second adhesive layer to glass in the above relationship, the first adhesive layer firmly adheres to an adherend such as glass. Therefore, it becomes easy to suppress air entrainment when the second pressure-sensitive adhesive layer is attached to an adherend.

The adhesive strength of the first pressure-sensitive adhesive layer to glass is preferably 1 N/25 mm or more, more preferably 5 N/25 mm or more, and even more preferably 10 N/25 mm or more. Further, the adhesive strength of the first pressure-sensitive adhesive layer to glass is preferably 50 N/25 mm or less.

The adhesive strength of the second pressure-sensitive adhesive layer to glass is preferably 0.01 N/25 mm or more. Further, the adhesive strength of the second pressure-sensitive adhesive layer to glass is preferably 1.5/25 mm or less, more preferably 0.5 N/25 mm or less, and 0.2 N/25 mm or less. Especially preferred.

The adhesive strength of the double-sided adhesive sheet to glass was measured 24 hours after the adhesive surface of each adhesive layer was attached to soda glass, according to JIS Z 0237 method 1, at a peel speed of 300 mm / min and a peel angle. It is a value measured under the condition of 180°.

In the double-sided pressure-sensitive adhesive sheet with a release sheet of the present invention, the second pressure-sensitive adhesive layer is directly laminated on the first pressure-sensitive adhesive layer. It is preferable that the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer are firmly adhered, and the interfacial adhesive strength between the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer is 1 N/25 mm or more. is preferred, 5 N/25 mm or more is more preferred, and 10 N/25 mm or more is even more preferred. Although the upper limit of the interfacial adhesive strength between the first adhesive layer and the second adhesive layer is not particularly limited, it is preferably 100 N/25 mm, for example. As described above, in the double-sided pressure-sensitive adhesive sheet, the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer are strongly adhered to each other, and the interlayer adhesion is excellent. By setting the interfacial adhesive strength between the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer within the above range, when the double-sided pressure-sensitive adhesive sheet is attached to the adherend and then peeled off (when reworking ), the occurrence of delamination between the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer can be suppressed, and as a result, reworkability can be enhanced.

The interfacial adhesive force between the first adhesive layer and the second adhesive layer can be measured after preparing a sample for interfacial adhesive force measurement as described in the Examples.
24 hours after obtaining the "double-sided pressure-sensitive adhesive sheet with a double-sided backing substrate" as described in the examples (24 hours after the second pressure-sensitive adhesive layer surface and the first pressure-sensitive adhesive layer surface are attached), By peeling the second backing substrate according to JIS Z 0237 method 1 at a peel speed of 300 mm / min and a peel angle of 180 °, the "first adhesive layer / second adhesive layer" interface Adhesion measurement is performed.

As described above, by adjusting the adhesive strength of each adhesive layer to glass and the interfacial adhesive strength between the adhesive layers within the above range, both strong adhesive strength and excellent reworkability to the adherend can be achieved. A double-sided pressure-sensitive adhesive sheet is obtained. Here, excellent reworkability means that part of the adhesive of the double-sided pressure-sensitive adhesive sheet does not remain on the adherend when the double-sided pressure-sensitive adhesive sheet is attached to the adherend and then peeled off, and rework work is performed. It refers to the property that the double-sided adhesive sheet does not break inside. Furthermore, one side of the double-sided pressure-sensitive adhesive sheet can exhibit a strong adhesive force to an adherend, and particularly a strong adhesive force to a glass surface. Thus, the double-sided pressure-sensitive adhesive sheet obtained by peeling off the release sheet from the double-sided pressure-sensitive adhesive sheet with a release sheet of the present invention has both strong adhesive strength and excellent reworkability.

Furthermore, since the double-sided pressure-sensitive adhesive sheet obtained by peeling off the release sheet from the double-sided pressure-sensitive adhesive sheet with a release sheet of the present invention does not have a support (substrate) between the pressure-sensitive adhesive layers, the double-sided pressure-sensitive adhesive sheet is flexible. have. Therefore, the double-sided pressure-sensitive adhesive sheet can exhibit excellent conformability to unevenness, and can be attached to an adherend having an uneven structure (stepped structure). The layer in contact with the uneven structure (stepped structure) may be the first pressure-sensitive adhesive layer or the second pressure-sensitive adhesive layer.

The total thickness of the double-sided pressure-sensitive adhesive sheet with a release sheet of the present invention is preferably 100 μm or more, more preferably 150 μm or more, even more preferably 200 μm or more. The thickness of the double-sided pressure-sensitive adhesive sheet with a release sheet is preferably 1200 μm or less, more preferably 800 μm or less, and even more preferably 500 μm or less. By setting the total thickness of the double-sided pressure-sensitive adhesive sheet with a release sheet within the above range, the workability of the double-sided pressure-sensitive adhesive sheet with a release sheet can be improved, and the ease of peeling of the release sheet can be improved.

The thickness of the double-sided pressure-sensitive adhesive sheet is preferably 10 µm or more, more preferably 20 µm or more, and even more preferably 50 µm or more. Also, the 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 total thickness of the double-sided PSA sheet within the above range, it becomes easier to achieve both strong adhesive strength and excellent reworkability.

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

In the present invention, when the thickness (μm) of the first adhesive layer is P and the thickness (μm) of the second adhesive layer is Q, P:Q=1:10 to 10:1. is preferred. By setting P:Q within the above range, one side of the double-sided pressure-sensitive adhesive sheet exhibits strong adhesive strength to the adherend, while the other side exhibits excellent reworkability. Sheets are easier to obtain. In addition, when the double-sided pressure-sensitive adhesive sheet includes two or more first pressure-sensitive adhesive layers, the above-mentioned P represents the total thickness of the first pressure-sensitive adhesive layers, and the above-mentioned Q represents the second thickness of the double-sided pressure-sensitive adhesive sheet. When two or more pressure-sensitive adhesive layers are included, it represents the total thickness of the second pressure-sensitive adhesive layer.

The thickness of the first release sheet in the double-sided pressure-sensitive adhesive sheet with a release sheet is preferably 5 µm or more, more preferably 20 µm or more, and even more preferably 30 µm or more. The thickness of the first release sheet is preferably 200 μm or less, more preferably 130 μm or less, even more preferably 100 μm or less.
The thickness of the second release sheet is preferably 5 µm or more, more preferably 20 µm or more, and even more preferably 30 µm or more. The thickness of the second release sheet is preferably 200 μm or less, more preferably 130 μm or less, even more preferably 100 μm or less. By setting the thicknesses of the first release sheet and the second release sheet within the above range, the processability of the double-sided pressure-sensitive adhesive sheet with a release sheet can be improved, and the ease of peeling of the release sheet can be improved.

The haze of the double-sided PSA sheet is preferably 3% or less, more preferably 1% or less. As used herein, the haze of a double-sided pressure-sensitive adhesive sheet refers to a value measured by a method conforming to JIS K7136. When measuring the haze, the first adhesive layer surface of the double-sided adhesive sheet is attached to a slide glass (product number: S9112) manufactured by Matsunami Glass Co., Ltd. to measure the haze value. Specifically, after bonding the double-sided adhesive sheet to a slide glass manufactured by Matsunami Glass Co., Ltd., the laminated sample was subjected to a pressure of 0.5 MPa and 40° C. in order to eliminate the influence of fine air mixed in during bonding. Autoclave (pressure defoaming) treatment for 30 minutes under the conditions of . After that, the second release sheet is peeled off, and the measurement is performed using NDH4000 manufactured by Nippon Denshoku Industries Co., Ltd. with the adhesive surface exposed.

The total light transmittance of the double-sided pressure-sensitive adhesive sheet is preferably 80% or higher, more preferably 85% or higher, even more preferably 90% or higher. The double-sided pressure-sensitive adhesive sheet is characterized by high total light transmittance and excellent transparency. As used herein, the total light transmittance of the double-sided pressure-sensitive adhesive sheet refers to a value measured by a method conforming to JIS K7136. The total light transmittance of the double-sided PSA sheet can be measured by the same method as the method for measuring the haze value described above.

<First adhesive layer>
The double-sided pressure-sensitive adhesive sheet with a release sheet of the present invention includes a first pressure-sensitive adhesive layer. In the present invention, the first pressure-sensitive adhesive layer is not particularly limited as long as it can exhibit the above-described adhesive strength and peeling strength. Among them, the first pressure-sensitive adhesive layer is preferably an acrylic pressure-sensitive adhesive layer.

When the first pressure-sensitive adhesive layer is an acrylic pressure-sensitive adhesive layer, the first pressure-sensitive adhesive layer is a layer containing acrylic resin as a main component. Specifically, the content of the acrylic resin in the first pressure-sensitive adhesive layer is preferably 50% by mass or more, more preferably 60% by mass or more, relative to the total weight of the first pressure-sensitive adhesive layer. More preferably, it is 70% by mass or more, even more preferably 80% by mass or more, and particularly preferably 90% by mass or more.

Examples of acrylic resins include acrylic pressure-sensitive adhesives containing acrylic polymers as base polymers. The acrylic polymer may contain at least one selected from non-crosslinkable (meth)acrylic acid ester units, acrylic monomer units having a crosslinkable functional group, and bifunctional acrylic monomer units. preferable. Here, "monomer unit" is a repeating unit that constitutes a polymer. An "acrylic monomer" is a compound having a (meth)acryloyl group. A "(meth)acryloyl group" indicates an acryloyl group or a methacryloyl group. A non-crosslinkable acrylic monomer is an acrylic monomer having no crosslinkable group, and a crosslinkable acrylic monomer is a monomer having a crosslinkable group. The crosslinkable acrylic monomer may be an acrylic monomer or a non-acrylic monomer as long as it can be polymerized with a non-crosslinkable acrylic monomer, but it must be an acrylic monomer. is preferred. In addition, a carboxy group, a hydroxy group, an amino group, an epoxy group, a glycidyl group etc. are mentioned as a crosslinkable group.

Examples of non-crosslinkable acrylic monomer units include (meth)acrylic acid ester units in which the hydrogen atoms of the carboxy group of (meth)acrylic acid are substituted with hydrocarbon groups. In the present invention, the acrylic pressure-sensitive adhesive layer preferably contains (meth)acrylate units.

Specific examples of (meth) acrylic esters include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, ( Isobutyl (meth)acrylate, t-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate , isooctyl (meth)acrylate, n-nonyl (meth)acrylate, isobornyl (meth)acrylate, isononyl (meth)acrylate, n-decyl (meth)acrylate, isodecyl (meth)acrylate, (meth)acrylate n-undecyl acrylate, n-dodecyl (meth)acrylate, stearyl (meth)acrylate, methoxyethyl (meth)acrylate, ethoxyethyl (meth)acrylate, cyclohexyl (meth)acrylate, (meth)acrylic acid benzyl. Among them, n-butyl acrylate, 2-ethylhexyl acrylate, and methyl acrylate are preferably used from the viewpoint of adhesiveness. These may be used individually by 1 type, and may use 2 or more types together. In the present invention, "(meth)acrylic acid" means to include both "acrylic acid" and "methacrylic acid".

Examples of crosslinkable acrylic monomer units include carboxy group-containing copolymerizable monomer units, hydroxy group-containing copolymerizable monomer units, amino group-containing copolymerizable monomer units, glycidyl group-containing copolymerizable monomer units, mer units.
Carboxy group-containing copolymerizable monomers include α,β-unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, glutaconic acid, and their anhydrides. things, etc.
Examples of hydroxy group-containing copolymerizable monomers include (meth)acrylic acid such as 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and 2-hydroxypropyl (meth)acrylate. (Meth)acrylic acid [(mono-, di- or poly)alkylene glycol] such as hydroxyalkyl, (meth)acrylic acid mono(diethylene glycol), and (meth)acrylic acid lactone such as (meth)acrylic acid monocaprolactone.
Examples of amino group-containing copolymerizable monomers include (meth)acrylamide and allylamide.
Examples of glycidyl group-containing copolymerizable monomers include glycidyl (meth)acrylate.

The acrylic polymer is preferably an acrylic random copolymer, more preferably a random copolymer of a crosslinkable acrylic monomer and a non-crosslinkable acrylic monomer. More specifically, it is preferably a random copolymer of acrylic acid and at least one selected from n-butyl acrylate, 2-ethylhexyl acrylate and methyl acrylate, and an acrylic acid ester copolymer. is preferred.

The weight average molecular weight (Mw) of the acrylic polymer is preferably 200,000 or more and 2,500,000 or less, more preferably 300,000 or more and 2,000,000 or less. The weight average molecular weight (Mw) is calculated based on a calibration curve prepared by gel permeation chromatography (GPC) using polystyrene standard substances.

Measurement conditions for gel permeation chromatography (GPC) are as follows.
Solvent: Tetrahydrofuran Column: Shodex KF801, KF803L, KF806L (three columns manufactured by Showa Denko Co., Ltd. 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 rate): 0.8 ml/min
Injection volume: 10 μl
Calibration curve: standard polystyrene Shodex standard Polystyrene (manufactured by Showa Denko KK) Mw = 1320 to 2,500,000 A calibration curve of 10 samples was used.

The first adhesive layer may contain a silane coupling agent. By including a silane coupling agent in the first pressure-sensitive adhesive layer, the interfacial adhesive strength between the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer can be further enhanced. Silane coupling agents include, for example, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2-(3,4-epoxycyclohexyl). Epoxy group-containing silane coupling agents such as ethyltrimethoxysilane; 3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl-N-(1, 3-dimethylbutylidene)propylamine, amino group-containing silane coupling agents such as N-phenyl-γ-aminopropyltrimethoxysilane; meth) acrylic group-containing silane coupling agents; isocyanate group-containing silane coupling agents such as 3-isocyanatopropyltriethoxysilane; Among them, the silane coupling agent is preferably an epoxy group-containing silane coupling agent.

As the silane coupling agent, one having a plurality of alkoxysilyl groups in the molecule can also be used. Examples of such silane coupling agents include X-41-1053, X-41-1059A, X-41-1056, X-41-1805, X-41-1818, and X -41-1810, X-40-2651 and the like.

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

The first pressure-sensitive adhesive layer may contain a cross-linking agent. That is, the pressure-sensitive adhesive composition forming the first pressure-sensitive adhesive layer preferably contains a cross-linking agent. For example, when the pressure-sensitive adhesive composition contains the above-described crosslinkable acrylic monomer, the crosslinker can promote the crosslink reaction of the crosslinkable acrylic monomer. As the cross-linking agent, for example, among known cross-linking agents such as isocyanate compounds, epoxy compounds, oxazoline compounds, aziridine compounds, metal chelate compounds, butylated melamine compounds, and polyfunctional acrylates, the cross-linking properties of the cross-linkable acrylic polymer can be selected. It can be appropriately selected in consideration of the reactivity with the functional group. The method of cross-linking can be selected from known methods such as thermal cross-linking and ionizing radiation cross-linking. In addition, after forming the adhesive layer agent, curing treatment may be performed in an environment of 23° C. in order to further increase the degree of cross-linking.

Examples of isocyanate compounds include tolylene diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and the like. The diisocyanate may be used as it is, or may be used as a trifunctional derivative such as an adduct, a nurate, or a burette.
Examples of epoxy compounds include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, glycerin diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diol. glycidyl ether, tetraglycidylxylenediamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, trimethylolpropane polyglycidyl ether, diglycerol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitol polyglycidyl ether, etc. 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 in the pressure-sensitive adhesive composition forming the first pressure-sensitive adhesive layer is appropriately selected according to the desired adhesive physical properties and is not particularly limited, but the polymer 100 contained in the pressure-sensitive adhesive composition It is preferably 0.01 parts by mass or more and 5 parts by mass or less with respect to parts by mass.

The first pressure-sensitive adhesive layer contains, if necessary, a plasticizer, an antioxidant, a metal corrosion inhibitor, a tackifier, an ultraviolet absorber, an antistatic agent, a photopolymerization initiator, a light stabilizer such as a hindered amine compound, and the like. may contain additives.
As a plasticizer, for example, a non-functional acrylic polymer can be used. A non-functional acrylic polymer is a polymer consisting only of acrylic monomer units that have no functional groups other than acrylate groups, or acrylic monomer units that have no functional groups other than acrylate groups and no functional groups. It means a polymer consisting of non-acrylic monomer units.
Examples of antioxidants include phenol antioxidants, amine antioxidants, lactone antioxidants, phosphorus antioxidants, sulfur antioxidants, and the like. One type of these antioxidants may be used alone, or two or more types may be used in combination.
Examples of metal corrosion inhibitors include benzoriazole-based resins.
Examples of tackifiers include rosin-based resins, terpene-based resins, terpene-phenol-based resins, coumarone-indene-based resins, styrene-based resins, xylene-based resins, phenol-based resins, and petroleum resins.
Examples of ultraviolet absorbers include benzotriazole-based compounds and benzophenone-based compounds.

Moreover, it is preferable to add an anti-aging agent in order to prevent the deterioration of the first pressure-sensitive adhesive layer over time. By adding an anti-aging agent, it is possible to prevent deterioration of the double-sided PSA sheet from lowering the adhesive strength. Anti-aging agents include general phenol-based antioxidants, phosphorus-based antioxidants, UV inhibitors, HALS (hindered amine-based stabilizers), and the like.

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

Examples of solvents include hydrocarbons such as hexane, heptane, octane, toluene, xylene, ethylbenzene, cyclohexane, and methylcyclohexane; halogenated hydrocarbons such as dichloromethane, trichloroethane, trichlorethylene, 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 , Esters such as ethyl acetate, butyl acetate, isobutyl acetate, amyl acetate, and ethyl butyrate; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene Polyols such as glycol monomethyl ether acetate and derivatives thereof are included.

<Second adhesive layer>
The double-sided pressure-sensitive adhesive sheet with a release sheet of the present invention includes a second pressure-sensitive adhesive layer. In the present invention, the second pressure-sensitive adhesive layer is not particularly limited as long as it can exhibit the above-described adhesive strength and peeling strength. As the adhesive for forming the second adhesive layer, an acrylic adhesive, a urethane adhesive, a silicone adhesive, or the like is preferable, and among them, a silicone adhesive having good air release property is particularly preferably used.

When the second pressure-sensitive adhesive layer is a silicone-based pressure-sensitive adhesive layer, the second 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 second pressure-sensitive adhesive layer is preferably 50% by mass or more, more preferably 60% by mass or more, relative to the total mass of the second pressure-sensitive adhesive layer. More preferably, it is 70% by mass or more, even more preferably 80% by mass or more, and particularly preferably 90% by mass or more.

Examples of silicone-based resins include silicone-based resins having a polysiloxane skeleton. Silicone resins include addition reaction type, condensation reaction type, ultraviolet curing type, electron beam curing type, and the like. Among them, addition reaction type silicone resins are preferably used because of their high reactivity and excellent productivity. Examples of addition-reactive silicone resins include organopoly resins having two or more alkenyl groups having 2 to 10 carbon atoms, such as vinyl groups, allyl groups, propenyl groups, and hexenyl groups, at the ends and/or side chains of the molecule. Siloxane is mentioned.

When using an addition reaction type silicone resin, it is preferable to use a cross-linking agent and a catalyst together. Cross-linking agents include, for example, organopolysiloxanes having at least two silicon-bonded hydrogen atoms per molecule. Specifically, dimethylhydrogensiloxy group end-blocked dimethylsiloxane-methylhydrogensiloxane copolymer, trimethylsiloxy group end-blocked dimethylsiloxane-methylhydrogensiloxane copolymer, trimethylsiloxy group end-blocked methylhydrogenpolysiloxane, and poly(hydrogensilsesquioxane).
As catalysts, fine particle platinum, fine particle platinum adsorbed on a carbon powder carrier, chloroplatinic acid, alcohol-modified chloroplatinic acid, olefin complexes of chloroplatinic acid, platinum compounds such as palladium and rhodium, and the like. mentioned.

A commercial item can be used as a silicone pressure sensitive adhesive. Examples of such silicone adhesives include KR-3704 and X40-3306 manufactured by Shin-Etsu Chemical Co., Ltd.; DC7651ADHESIVE and SD7587LPSA manufactured by Dow Corning Toray Co., Ltd.; SE9600 etc. are mentioned.

A urethane-based pressure-sensitive adhesive is a pressure-sensitive adhesive mainly composed of a reaction product of a polyol and a polyisocyanate. The polyol is preferably a known polyol having two or more hydroxyl groups. Polyols include, for example, polyacrylic polyols, polyether polyols, polyester polyols, polycaprolactone polyols, polycarbonate polyols, and castor oil-based polyols. Preferred polyisocyanates are known aromatic polyisocyanates, aliphatic polyisocyanates, araliphatic polyisocyanates, alicyclic polyisocyanates, and the like. A known catalyst can be used for the reaction between the polyol and the polyisocyanate. Examples of catalysts include tertiary amine compounds and organometallic compounds.

The hydroxyl value of the urethane adhesive is preferably 1 to 30 mgKOH/g, more preferably 10 to 25 mgKOH/g. The hydroxyl value can be adjusted by a known method such as adjusting the mixing ratio of polyol and polyisocyanate. When the hydroxyl value is within a predetermined range, it is easy to obtain a pressure-sensitive adhesive layer with a good crosslink density, and the wettability is further improved.

A commercial item can be used as a urethane-type adhesive. Such urethane pressure-sensitive adhesives include SH-101, SH-101M, SH-109 manufactured by Toyochem Co., Ltd., and the like.

Examples of acrylic pressure-sensitive adhesives include acrylic light pressure-sensitive adhesives containing an acrylic polymer as a base polymer. The acrylic polymer may contain at least one selected from non-crosslinkable (meth)acrylic acid ester units, acrylic monomer units having a crosslinkable functional group, and bifunctional acrylic monomer units. preferable.

A commercial item can be used as an acrylic adhesive. Examples of such an acrylic pressure-sensitive adhesive include FINETAC CT-3088 manufactured by DIC Corporation, BPS6078TF manufactured by Toyochem Co., Ltd., and the like.

The second pressure-sensitive adhesive layer may optionally contain additives such as antioxidants, metal corrosion inhibitors, tackifiers, ultraviolet absorbers, hindered amine compounds, antistatic agents, and light stabilizers. good.
Examples of antioxidants include phenol antioxidants, amine antioxidants, lactone antioxidants, phosphorus antioxidants, sulfur antioxidants, and the like. One type of these antioxidants may be used alone, or two or more types may be used in combination.
Examples of metal corrosion inhibitors include benzoriazole-based resins.
Examples of tackifiers include rosin-based resins, terpene-based resins, terpene-phenol-based resins, coumarone-indene-based resins, styrene-based resins, xylene-based resins, phenol-based resins, and petroleum resins.
Examples of ultraviolet absorbers include benzotriazole-based compounds and benzophenone-based compounds.

In addition, it is preferable to add an antiaging agent in order to prevent deterioration over time of the second pressure-sensitive adhesive layer. By adding an anti-aging agent, it is possible to prevent deterioration of the double-sided PSA sheet from lowering the adhesive strength. Anti-aging agents include general phenol-based antioxidants, phosphorus-based antioxidants, UV inhibitors, HALS (hindered amine-based stabilizers), and the like.

The adhesive composition forming the second adhesive layer may contain a solvent. The solvent evaporates during the formation of the pressure-sensitive adhesive layer, but the second pressure-sensitive adhesive layer may contain residual solvent. Examples of the solvent include the same solvents as those that can be contained in the adhesive composition forming the first adhesive layer.

<First release sheet>
The double-sided pressure-sensitive adhesive sheet with a release sheet of the present invention includes a first release sheet. The first release sheet is preferably a release laminate sheet having a release sheet substrate and a release agent layer provided on one side of the release sheet substrate. Papers and polymer films are used as the base material for the release sheet in the release laminate sheet. Examples of the polymer film used as the base material for the release sheet include polyethylene terephthalate resin film, polypropylene resin film, polyimide resin film and the like. Among them, a polyethylene terephthalate resin film is particularly preferable in terms of economy and surface smoothness.

The release agent layer in the release laminate sheet is preferably composed of a release agent, and the release agent is preferably a silicone-based release agent. That is, the first release sheet is preferably a sheet containing a silicone-based release agent, and more preferably a sheet including a release agent layer composed of a silicone-based release agent.

Examples of silicone-based release agents include addition-type silicone-based release agents and condensation-type silicone-based release agents. Among them, an addition-type silicone-based release agent having high reactivity is preferably used. Specific examples of silicone release agents include BY24-4527 and SD-7220 manufactured by Toray Dow Corning Silicone Co., Ltd., and KS-3600, KS-774 and X62-2600 manufactured by Shin-Etsu Chemical Co., Ltd. is mentioned. The silicone release agent may also contain a silicone resin which is an organosilicon compound having _SiO2 units and ( _CH3 )3SiO1 _{/ 2} units or _CH2 =CH( _CH3 )SiO1 _/2 units. .

The silicone release agent may contain polyorganosiloxane and polyorganohydrogensiloxane. The polyorganosiloxane preferably has at least two alkenyl groups directly bonded to silicon atoms in one molecule, and furthermore, has at least two epoxy groups bonded to silicon atoms via carbon atoms in one molecule. It is preferable to use together a polyorganosiloxane having a group and substantially free of hydrogen atoms directly bonded to silicon atoms. The polyorganohydrogensiloxane preferably has at least three hydrogen atoms directly bonded to silicon atoms in one molecule and has a kinematic viscosity at 25° C. of 1 mm ² /s or more. In addition, the silicone-based release agent may contain a platinum-based catalyst. Specific examples of silicone-based release agents and platinum-based catalysts containing polyorganosiloxane and polyorganohydrogensiloxane include Shin-Etsu Chemical Co., Ltd. KS-3800, X-62-183, X-62-2829, X -62-2853, X-62-2856, X-62-2857, PL-5000, PL-50T, LTC-856 manufactured by Dow Corning Toray Co., Ltd., LTC-761, SRX-212, Momentive Co., Ltd. manufactured by XS56-C4880, XS56-C4617, XS56-C4434, TPR-6600, XC94-C4326 and the like. Furthermore, a release control agent may be used in combination to adjust the release property of the release agent layer.

The coating amount of the release agent on the first release sheet is preferably 0.05 to 0.5 g/m ² , more preferably 0.08 to 0.3 g/m ² , and more preferably 0.1 to 0.1 g/m 2 . More preferably 0.2 g/m ² . The thickness of the release agent layer of the first release sheet is preferably 50 to 500 nm, more preferably 80 to 300 nm, even more preferably 100 to 200 nm. As a method for providing the release agent layer, conventionally known coating methods such as reverse roll coating, gravure coating, bar coating, and doctor blade coating can be used.

The peel force for peeling the first release sheet from the first pressure-sensitive adhesive layer is preferably 0.01 N/50 mm or more, more preferably 0.1 N/50 mm or more. In addition, the peel force when peeling the first release sheet from the first pressure-sensitive adhesive layer is preferably 1.0 N/50 mm or less, more preferably 0.8 N/50 mm or less, and 0.8 N/50 mm or less. It is more preferably 6N/50mm or less.

The peel force when peeling the first release sheet from the first adhesive layer is the first release sheet/first adhesive layer/second adhesive layer/second release sheet in this order. The laminated double-sided pressure-sensitive adhesive sheet with a release sheet is cut into 50 mm × 100 mm, and the first release sheet is peeled according to JIS Z 0237 method 1 at a peel speed of 300 mm / min and a peel angle of 180 °. .

<Second release sheet>
The double-sided pressure-sensitive adhesive sheet with a release sheet of the present invention includes a second release sheet. The second release sheet may be a release laminate sheet having a release sheet base material and a release agent layer provided on one side of the release sheet base material, and consists only of the release sheet base material. It may be a sheet. Papers and polymer films are used as the base material for the release sheet in the release laminate sheet. Further, when the second release sheet is a sheet consisting only of a release sheet base material, the release sheet base material is preferably a base material consisting of a polymer film. Examples of the polymer film used as the base material for the release sheet include polyethylene terephthalate resin film, polypropylene resin film, polyimide resin film and the like. A polyethylene terephthalate resin film is particularly preferred in terms of economy and surface smoothness.

The peel load of the second release sheet is preferably 70 to 20000 mN/50 mm. Even when a release sheet coated with a release agent is used as the second release sheet, the release load of the second release sheet is preferably within the above range. The peel load of the second release sheet is preferably 100 to 18000 mN/50 mm, more preferably 120 to 17000 mN/50 mm. By setting the peel load of the second release sheet to the above lower limit or more, the peel force of the second release sheet from the second adhesive layer is increased to the level of the peeling force of the second release sheet from the first adhesive layer of the first release sheet. It becomes easy to make it larger than the force. Here, the peeling load is No. The surface of the second release sheet to which the second adhesive layer surface is attached is attached to the adhesive layer of No. 100, and after leaving it at room temperature for 24 hours, it is peeled at 180° and the second adhesive layer is peeled at a peeling speed of 300 m / min. This is the peel force when the release sheet is peeled off.

When the second release sheet is a release laminated sheet having a release sheet substrate and a release agent layer provided on one side of the release sheet substrate, the release agent layer is composed of a release agent. is preferred. In this case, the release agent is preferably a fluorosilicone release agent. A fluorosilicone release agent contains at least one fluorine atom-containing organic group in one molecule.

When the second release sheet is a release laminate sheet having a release sheet substrate and a release agent layer provided on one side of the release sheet substrate, the release agent may be a non-silicone release agent. good. Examples of non-silicone release agents include amino alkyd resins.

The second release sheet preferably contains the non-silicone release agent as described above, or the total content of the silicone release agent and the non-silicone release agent is 1% by mass or less. That is, it is preferable that the second release sheet either contain the non-silicone release agent as described above or contain substantially no release agent. In this specification, when the content of the release agent in the second release sheet is 1% by mass or less, the release agent is not substantially contained. In addition, when the second release sheet does not substantially contain a release agent, the second release sheet is preferably a substrate made of a polymer film. Examples of polymer films include polyester films.

When the second release sheet contains a release agent, the thickness of the release agent layer is preferably 0.03 μm or more and 5 μm or less, more preferably 0.05 μm or more and 2 μm or less, and 0.08 μm or more and 1 μm. More preferably: As a method for providing the release agent layer, conventionally known coating methods such as reverse roll coating, gravure coating, bar coating, and doctor blade coating can be used.

The peel force for peeling the second release sheet from the second pressure-sensitive adhesive layer is preferably 0.5 N/50 mm or more, more preferably 0.6 N/50 mm or more. In addition, the peel force when peeling the second release sheet from the second pressure-sensitive adhesive layer is preferably 10.0 N/50 mm or less, more preferably 5.0 N/50 mm or less. It is more preferably 0 N/50 mm or less.

When measuring the peel force when peeling the second release sheet from the second pressure-sensitive adhesive layer, first, the first release sheet / first pressure-sensitive adhesive layer / second pressure-sensitive adhesive layer / second Cut out a double-sided adhesive sheet with a release sheet in which the release sheets are laminated in this order to 50 mm × 100 mm, and attach a PET film with an easy adhesion layer manufactured by Toyobo (A4300 # 100) as a backing base material to the first release sheet. do. Thereafter, the second release sheet is peeled off according to JIS Z 0237 Method 1 at a peel speed of 300 mm/min and a peel angle of 180° to measure the peel strength.

In the double-sided pressure-sensitive adhesive sheet with a release sheet of the present invention, each release sheet has a different release force, and the release force when peeling the second release sheet from the second pressure-sensitive adhesive layer is the same as the first pressure-sensitive adhesive layer. It is greater than the peeling force when peeling the first release sheet from the agent layer. When the release force for peeling the second release sheet from the second pressure-sensitive adhesive layer is _RH , and the release force for peeling the first release sheet from the first pressure-sensitive adhesive layer is _RL , The ratio of R _H to R _L (R _H /R _L ) is preferably 1.2 or more, more preferably 1.5 or more.

(Manufacturing method of double-sided pressure-sensitive adhesive sheet with release sheet)
The method for producing the double-sided pressure-sensitive adhesive sheet with a release sheet is not particularly limited, but the production process of the double-sided pressure-sensitive adhesive sheet with a release sheet of the present invention comprises forming a first pressure-sensitive adhesive layer on a first release sheet, forming a second pressure-sensitive adhesive layer on a first release sheet, It is preferable to include a step of forming a second pressure-sensitive adhesive layer on a release sheet, and a step of laminating the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer so as to be in contact with each other. The step of forming each pressure-sensitive adhesive layer on each release sheet is preferably a step of coating each pressure-sensitive adhesive composition constituting each pressure-sensitive adhesive layer onto the release sheet. Alternatively, the first adhesive layer and the second adhesive layer are simultaneously or sequentially formed on the first release sheet or the second release sheet, and the second release sheet or the first release sheet is laminated. You may

Coating of each pressure-sensitive adhesive composition can be carried out using a known coating apparatus. Coating devices include, for example, blade coaters, air knife coaters, roll coaters, bar coaters, gravure coaters, micro gravure coaters, rod blade coaters, lip coaters, die coaters and curtain coaters.
Moreover, it is preferable to provide a drying process after coating, and the drying process can be performed using a known heating device such as a heating furnace or an infrared lamp. Thus, the first adhesive layer is formed on the first release sheet, and the second adhesive layer is formed on the second release sheet.

The step of laminating the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer so as to be in contact with each other includes the step of stacking the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer so as to be in direct contact and pressing them together. is preferred. The method of pressure bonding is not particularly limited, but it is preferable to use a roll bonding machine capable of continuous pressure bonding. In this way, a double-sided pressure-sensitive adhesive sheet with a release sheet is obtained in which the first release sheet, the first pressure-sensitive adhesive layer, the second pressure-sensitive adhesive layer and the second release sheet are laminated in this order.

Before the step of laminating the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer so that they are in contact with each other, each pressure-sensitive adhesive layer may be subjected to a surface activation treatment. Here, examples of the surface activation treatment include corona treatment and plasma treatment.

The surface activation treatment is preferably applied to the bonding surface side of each pressure-sensitive adhesive layer. The surface activation treatment may be applied to one selected from the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer, or may be applied to both. For example, when the first pressure-sensitive adhesive layer is surface-activated, the wetting 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. Moreover, the wetting tension of the first pressure-sensitive adhesive layer after surface activation treatment is preferably 1.1 times or more the wetting tension of the first pressure-sensitive adhesive layer before surface activation treatment. When the surface activation treatment is applied only to either the first pressure-sensitive adhesive layer or the second pressure-sensitive adhesive layer, the surface activation treatment is preferably applied to the first pressure-sensitive adhesive layer. .

When the surface on the interface side of the second pressure-sensitive adhesive layer is a surface-activated surface, the wetting tension of the surface-activated surface is preferably 30 mN/m or more, more preferably 34 mN/m or more. preferable. Although the upper limit of the wetting tension of the surface-activated surface is not particularly limited, it is preferably, for example, 45 mN/m in order to prevent deterioration of transparency. The wetting tension is measured by applying a wetting indicator standard liquid (manufactured by Wako Pure Chemical Industries, Ltd.) to the surface of the adhesive layer according to JIS K 6768 1999.

As the corona treatment, there is a method in which a corona treatment machine is used to discharge electricity in normal pressure air. The corona output in the corona treatment is not particularly limited, but for example, it is preferably 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. It is more preferable that it is more than or equal to 6.0 kW or less. The treatment 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 even more preferably 5 m/min or more and 80 m/min or less. .

Plasma treatment includes a method of discharging in normal pressure air using a plasma discharger. Although the plasma output in the plasma treatment is not particularly limited, for example, it 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. More preferably, it is 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 even more preferably 5 m/min or more and 80 m/min or less. .

(Application)
The double-sided pressure-sensitive adhesive sheet with a release sheet of the present invention is preferably used for laminating various members after the release sheet is peeled off. Although the application for bonding is not limited, it is preferably for bonding optical members. Examples of optical members include liquid crystal displays and touch panels. In particular, the double-sided pressure-sensitive adhesive sheet from which the release sheet has been peeled off is preferably used for laminating glass and a liquid crystal display, or glass and a touch panel.

Alternatively, only one of the release sheets may be peeled off and attached to various members. For example, by peeling off the first release sheet of the double-sided pressure-sensitive adhesive sheet with a release sheet of the present invention and bonding the first pressure-sensitive adhesive layer to glass, the glass, the first pressure-sensitive adhesive layer, and the second pressure-sensitive adhesive A laminate in which the layer and the second release sheet are laminated in this order may be obtained. Such a laminate is preferably used, for example, as a protective film for optical members. In this case, general consumers may peel off the second release sheet of the laminate and attach it to a liquid crystal display. By using the double-sided pressure-sensitive adhesive sheet with a release sheet of the present invention, it is easy to process a laminate in which the glass, the first pressure-sensitive adhesive layer, the second pressure-sensitive adhesive layer and the second release sheet are laminated in this order, and it is possible to produce an optical member. Easy to process into a protective film. In addition, when general consumers peel off the second release sheet of the laminate and bond it to a liquid crystal display, air is less likely to be entrapped, and the protective film can be neatly bonded.

EXAMPLES The characteristics of the present invention will be described more specifically below with reference to examples and comparative examples. The materials, amounts used, proportions, treatment details, treatment procedures, etc. shown in the following examples can be changed as appropriate without departing from the gist of the present invention. Therefore, the scope of the present invention should not be construed to be limited by the specific examples shown below. In the following, Example 4 shall be read as Reference Example 4.

[Example 1]
<Preparation of acrylic adhesive composition>
(Adhesive composition 1A)
A (meth)acrylate polymer was prepared by copolymerizing 90 parts by mass of n-butyl acrylate (BA) and 10 parts by mass of acrylic acid (AA). The weight average molecular weight of this (meth)acrylate polymer was 500,000.
100 parts by mass of the obtained (meth)acrylic acid ester polymer, and 1,3-bis(N,N'-diglycidylaminomethyl)cyclohexane (TERAD-C manufactured by Mitsubishi Gas Chemical Company, Inc.) as an epoxy-based cross-linking agent. 05 parts by mass, and 0.15 parts by mass of a silicone alkoxy oligomer (X-41-1810, manufactured by Shin-Etsu Chemical Co., Ltd.) as a silane coupling agent. An acrylic pressure-sensitive adhesive composition was obtained by diluting with ethyl acetate so that the

<Preparation of silicone adhesive composition>
(Adhesive composition 2A)
Addition type organopolysiloxane (KS-847H, manufactured by Shin-Etsu Chemical Co., Ltd.) consisting of organopolysiloxane and organohydrogenpolysiloxane having a siloxane bond as a main skeleton and having a vinyl group 100 parts by mass (solid content conversion value; the same applies hereinafter) ), organopolysiloxane containing trifunctional or tetrafunctional siloxane units (silicone resin; manufactured by Dow Corning Toray Co., Ltd., SD-4584) 20 parts by mass, platinum catalyst (manufactured by Dow Corning Toray Co., Ltd., SRX-212)1. 5 parts by mass were mixed, sufficiently stirred, and diluted with methyl ethyl ketone so that the solid content concentration was 40% by mass, thereby obtaining a silicone pressure-sensitive adhesive composition.

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

Next, the silicone pressure-sensitive adhesive composition is applied to the surface of a polyethylene terephthalate film (manufactured by Toray Industries, Inc., Lumirror S-10#38) (second release sheet) having a thickness of 38 μm so that the coated amount after drying becomes 50 μm. and dried in an air circulating constant temperature oven at 100° C. for 3 minutes to obtain a silicone pressure-sensitive adhesive layer with a second release sheet adhered to one side. The peeling load of Lumirror S-10#10 was 16000 mN/50 mm.

A corona discharge treatment was applied to each surface of the acrylic pressure-sensitive adhesive layer and the silicone pressure-sensitive adhesive layer. The corona discharge treatment was performed using a corona surface treatment apparatus manufactured by Kasuga Denki. The corona discharge treatment was performed under conditions such that the acrylic pressure-sensitive adhesive layer had a wet tension of 70 mN/m or more and the silicone pressure-sensitive adhesive layer had a wet tension of 30 mN/m or more.
By bonding the exposed surface of the acrylic pressure-sensitive adhesive layer that has undergone surface activation treatment and the exposed surface of the silicone pressure-sensitive adhesive layer, the first release sheet/first pressure-sensitive adhesive layer (acrylic pressure-sensitive adhesive layer) A double-sided pressure-sensitive adhesive sheet with a release sheet was obtained in which /second pressure-sensitive adhesive layer (silicone-based pressure-sensitive adhesive layer)/second release sheet were laminated in this order.

[Example 2]
In <Production of double-sided pressure-sensitive adhesive sheet with release sheet>, except that the silicone-based pressure-sensitive adhesive composition was applied to the surface of a fluorosilicone-based release sheet (manufactured by Nippa, SS4C substrate thickness: 75 µm) (second release sheet). A double-sided pressure-sensitive adhesive sheet with a release sheet was obtained in the same manner as in Example 1. Incidentally, the peeling load of SS4C was 340 mN/50 mm.

[Example 3]
<Preparation of silicone adhesive composition>
(Adhesive composition 2B)
Shin-Etsu Chemical's silicone adhesive KR3704 and Shin-Etsu Chemical's platinum catalyst PL50T are sufficiently stirred at a ratio of 100/0.5 and diluted with toluene so that the solid content concentration is 40% by mass. Composition 2B was obtained.

A double-sided PSA sheet with a release sheet was obtained in the same manner as in Example 1, except that PSA composition 2B was used instead of the silicone-based PSA composition in <Preparation of double-sided PSA sheet with release sheet>.

[Example 4]
<Preparation of urethane adhesive composition>
(Adhesive composition 2C)
Adhesive by mixing 6 parts by mass of T-501B (solid content 75% by mass) manufactured by Toyochem Co., Ltd. as a polyisocyanate component with 100 parts by mass of a urethane slight adhesive SH-101 (solid content 60% by mass) manufactured by Toyochem Co., Ltd. Agent composition C was obtained.

A double-sided pressure-sensitive adhesive sheet with a release sheet was obtained in the same manner as in Example 2, except that the urethane-based pressure-sensitive adhesive composition 2C was used instead of the silicone-based pressure-sensitive adhesive composition 2A in <Preparation of a double-sided pressure-sensitive adhesive sheet with a release sheet>.

[Example 5]
<Preparation of acrylic adhesive composition>
(Adhesive composition 1B)
100 parts by mass of N-9369 manufactured by Nippon Synthetic Chemical Co., Ltd. and 0.9 parts by mass of curing agent L-55E are mixed, thoroughly stirred, and diluted with ethyl acetate so that the solid content concentration is 40% by mass. By doing so, an acrylic pressure-sensitive adhesive composition 1B was obtained.

<Preparation of silicone adhesive composition>
(Adhesive composition 2D)
Dow Corning Toray Co., Ltd. Dow Corning Co., Ltd. Dow Corning Toray Co., Ltd. Dow Corning Toray Co., Ltd. Dow Corning Toray Co., Ltd. Dow Corning Toray Co., Ltd. Dow Corning Toray Co., Ltd. Dow Corning Toray Co., Ltd. Dow Corning Toray Co., Ltd. Dow Corning Co., Ltd. Dow Corning Co., Ltd. The parts by mass were mixed, sufficiently stirred, and diluted with methyl ethyl ketone so that the solid content concentration was 40% by mass, thereby obtaining a silicone-based pressure-sensitive adhesive composition 2D.

<Production of double-sided adhesive sheet with release sheet>
In <Preparation of double-sided pressure-sensitive adhesive sheet with release sheet>, acrylic pressure-sensitive adhesive composition 1A was changed to acrylic pressure-sensitive adhesive composition 1B, and silicone-based pressure-sensitive adhesive composition 2A was changed to silicone-based pressure-sensitive adhesive composition 2D. A double-sided pressure-sensitive adhesive sheet with a release sheet was obtained in the same manner as in 1.

[Comparative Example 1]
In <Production of double-sided pressure-sensitive adhesive sheet with release sheet>, except that the silicone-based pressure-sensitive adhesive composition was applied to the surface of a fluorosilicone-based release sheet (manufactured by Nippa, FSC6 substrate thickness: 75 μm) (second release sheet). A double-sided pressure-sensitive adhesive sheet with a release sheet was obtained in the same manner as in Example 1. The peel load of FSC6 was 50 mN/50 mm.

[Comparative Example 2]
<Preparation of silicone adhesive composition>
(Adhesive composition 2E)
Shin-Etsu Chemical Silicone Adhesive KR3704, Shin-Etsu Chemical Silicone Adhesive KR3700, and Shin-Etsu Chemical Platinum Catalyst PL50T are mixed at a ratio of 90/10/0.5 and sufficiently stirred to obtain a solid content concentration of 40. A silicone pressure-sensitive adhesive composition 2E was obtained by diluting with toluene so as to obtain a mass %.

In <Preparation of double-sided PSA sheet with release sheet>, PSA composition 2E was used as the silicone PSA composition, and the second release sheet was a fluorosilicone release sheet (manufactured by Nippa, FSC6 substrate thickness: 75 μm). A double-sided pressure-sensitive adhesive sheet with a release sheet was obtained in the same manner as in Example 1 except for the above.

(measurement and evaluation)
<Measurement of adhesive strength>
(Adhesive strength of first adhesive layer)
The double-sided pressure-sensitive adhesive sheet with a release sheet obtained in the step of <Preparation of a double-sided pressure-sensitive adhesive sheet with a release sheet> was cut into a width of 25 mm x 10 cm. The surface was adhered to soda glass. The second release sheet was peeled off from the surface of the second pressure-sensitive adhesive layer, and the surface of the second pressure-sensitive adhesive layer was surface-activated. Thereafter, a polyethylene terephthalate film with an easy-adhesion layer to which an acrylic adhesive layer that had been similarly surface-activated was adhered was adhered as a backing substrate to the surface of the second pressure-sensitive adhesive layer. Twenty-four hours after the application, the adhesive strength of the first adhesive layer surface to glass was measured according to JIS Z 0237 Method 1 under the conditions of a peel speed of 300 mm/min and a peel angle of 180°. The polyethylene terephthalate film with an easy-adhesion layer to which a surface-activated acrylic adhesive layer is adhered has an acrylic adhesive layer made by New Tac Kasei Co., Ltd. CCL / D1 / T3T3 (PET film with an easy-adhesion layer made by Toyobo (A4300#100)).

(Adhesive strength of the second adhesive layer)
First release sheet/first pressure-sensitive adhesive layer/second pressure-sensitive adhesive layer/second release sheet are laminated in this order. A layered polyethylene terephthalate film (A4300#100 manufactured by Toyobo Co., Ltd.) was adhered as a backing substrate. The second release sheet was peeled off, and the adhesive surface of the second adhesive layer was adhered to soda glass. Twenty-four hours after the application, the adhesive force was measured according to JIS Z 0237 method 1 under the conditions of a peel speed of 300 mm/min and a peel angle of 180°.

<Interfacial Adhesion>
The first release sheet of the double-sided pressure-sensitive adhesive sheet with a release sheet is peeled off from the first pressure-sensitive adhesive layer, and the first pressure-sensitive adhesive layer surface is lined with a polyethylene terephthalate film with an easy-adhesion layer (manufactured by Toyobo, A4300 #100). It was adhered as a (first backing base material). Subsequently, the second release sheet was peeled off from the second pressure-sensitive adhesive layer, and the surface of the second pressure-sensitive adhesive layer was surface-activated. A polyethylene terephthalate film with an easy-adhesion layer, to which a surface-activated acrylic adhesive layer is adhered, is adhered as a backing substrate (second backing substrate) to the surface of the surface-activated second adhesive layer. bottom. The polyethylene terephthalate film with an easy-adhesion layer to which a surface-activated acrylic adhesive layer is adhered has an acrylic adhesive layer made by New Tac Kasei Co., Ltd. CCL / D1 / T3T3 (PET film with an easy-adhesion layer made by Toyobo (A4300#100)). The obtained double-sided pressure-sensitive adhesive sheet with a double-sided backing substrate was cut into a size of 50 mm×100 mm, and the surface opposite to the adhesive layer surface of the first backing substrate was fixed. 24 hours after the adhesion of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer, by peeling off the second backing substrate, the interfacial adhesive strength between the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer increases. was measured according to JIS Z 0237 method 1 under the conditions of a peel speed of 300 mm/min and a peel angle of 180°. In addition, when the interface other than the interface between the first adhesive layer and the second adhesive layer is peeled off, the adhesive force at the interface between the first adhesive layer and the second adhesive layer is defined as the peeling force or more. bottom.

<Measurement of peel strength>
(Release force of first release sheet)
A double-sided pressure-sensitive adhesive sheet with a release sheet in which a first release sheet/first pressure-sensitive adhesive layer/second pressure-sensitive adhesive layer/second release sheet are laminated in this order is cut into 50 mm × 100 mm, and a first release sheet is obtained. was peeled off at a peel speed of 300 mm/min and a peel angle of 180° according to JIS Z 0237 method 1, and the peel force was measured.

(Release force of second release sheet)
A double-sided pressure-sensitive adhesive sheet with a release sheet in which a first release sheet/first pressure-sensitive adhesive layer/second pressure-sensitive adhesive layer/second release sheet are laminated in this order is cut into 50 mm × 100 mm, and a first release sheet is obtained. was peeled off, and a PET film with an easily adhesive layer (A4300 #100) manufactured by Toyobo Co., Ltd. was attached as a backing substrate to the first adhesive layer surface. After that, the second release sheet was peeled off according to JIS Z 0237 method 1 under the conditions of a peel speed of 300 mm/min and a peel angle of 180°, and the peel force was measured.

<Peeling load>
The second release sheet of the double-sided pressure-sensitive adhesive sheet with a release sheet is peeled off, and the surface of the second release sheet coated with the release agent is wiped with a No. It was attached to the adhesive layer surface of No. 100 and allowed to stand at room temperature for 24 hours. After that, the peel force when the second release sheet was peeled off at 180° peeling at a peel speed of 300 m/min was measured and used as the peel load.

<Evaluation of workability>
When measuring the peel strength of the first release sheet, if 95% or more of the area of the second release sheet did not peel off from the second pressure-sensitive adhesive layer surface, the workability was evaluated as good (○). When more than 5% of the area of the second release sheet was peeled off from the second pressure-sensitive adhesive layer, the workability was poor (x).

<Evaluation of air release property>
The first release sheet of the double-sided pressure-sensitive adhesive sheet with a release sheet is peeled off from the first pressure-sensitive adhesive layer, and the surface of the first pressure-sensitive adhesive layer is rolled onto a glass plate made by Matsunami Glass (product name: S9112, 1 mmt × 76 mm × 52 mm) with a weight of 2 kg. The tape was pasted by making one reciprocating motion. Then, the second release sheet was peeled off, placed gently on the soda glass plate so that the second pressure-sensitive adhesive layer surface was directly superimposed, and adhered by its own weight. At this time, when the area of the air bubbles remaining at the interface between the second adhesive layer and the soda glass is 2% or less of the adhered area, the air release property is extremely good (◎), and when 2% or more and less than 5%, the air release property is excellent. Good air release property (x) was defined as those exceeding 5% of good property (○).

The double-sided pressure-sensitive adhesive sheets with release sheets obtained in the examples were able to peel off the first release sheet first, and had excellent workability. When the second pressure-sensitive adhesive layer was attached to the adherend, entrapment of air was suppressed. On the other hand, the double-sided pressure-sensitive adhesive sheets with a release sheet obtained in Comparative Examples did not have both workability and air release properties.

10 First adhesive layer 12 Second adhesive layer 20 First release sheet 22 Second release sheet 50 Double-sided adhesive sheet 100 Double-sided adhesive sheet with release sheet

Claims (5)

A double-sided pressure-sensitive adhesive sheet with a release sheet in which a first release sheet, a first pressure-sensitive adhesive layer, a second pressure-sensitive adhesive layer and a second release sheet are laminated in this order,
The first pressure-sensitive adhesive layer is an acrylic pressure-sensitive adhesive layer, the second pressure-sensitive adhesive layer is a silicone pressure-sensitive adhesive layer,
The first adhesive layer contains a silane coupling agent,
The interfacial adhesive strength between the first adhesive layer and the second adhesive layer is 10 N/25 mm or more,
The second adhesive layer is directly laminated on the first adhesive layer,
The adhesive strength to glass of the first adhesive layer is 10 to 1000 times the adhesive strength to glass of the second adhesive layer,
A release sheet, wherein the release force when peeling the second release sheet from the second pressure-sensitive adhesive layer is greater than the peel force when peeling the first release sheet from the first pressure-sensitive adhesive layer Double-sided adhesive sheet with. The peeling according to claim 1, wherein the first adhesive layer has an adhesive strength to glass of 1 to 50 N/25 mm, and the second adhesive layer has an adhesive strength to glass of 0.01 to 1 N/25 mm. Double-sided adhesive sheet with sheet. The double-sided pressure-sensitive adhesive sheet with a release sheet according to claim 1 or 2, wherein the first release sheet contains a silicone-based release agent. The double-sided pressure-sensitive adhesive sheet with a release sheet according to any one of claims 1 to 3, wherein the second release sheet has a release load of 70 to 20000 mN/50 mm. forming a first adhesive layer on a first release sheet and forming a second adhesive layer on a second release sheet;
A method for producing a double-sided pressure-sensitive adhesive sheet with a release sheet, comprising a step of laminating the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer so that they are in contact with each other,
The first pressure-sensitive adhesive layer is an acrylic pressure-sensitive adhesive layer, the second pressure-sensitive adhesive layer is a silicone pressure-sensitive adhesive layer,
The first adhesive layer contains a silane coupling agent,
The interfacial adhesive strength between the first adhesive layer and the second adhesive layer is 10 N/25 mm or more,
The adhesive strength to glass of the first adhesive layer is 10 to 1000 times the adhesive strength to glass of the second adhesive layer,
A method for producing a double-sided pressure-sensitive adhesive sheet with a release sheet, wherein the release force of the second release sheet is greater than the release force of the first release sheet.

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