JP2022156962A - Adhesive sheet and laminate - Google Patents

Abstract

To provide an adhesive sheet which enables recycling of a substrate even when heat treatment is performed, and a laminate using the adhesive sheet.SOLUTION: An adhesive sheet 1 includes a first adhesive layer 111 and a second adhesive layer 112, wherein the adhesive sheet 1 has a first adhesive surface in the first adhesive layer 111 and a second adhesive surface in the second adhesive layer 112; a pair glass adhesive force Fg2 at 23°C after a first laminate obtained by bonding the first adhesive surface in the adhesive sheet 1 to one surface of a glass plate has been heated at 100°C for 300 minutes, and the temperature of the first laminate has been lowered to 23°C is 0.1-7 N/25 mm; and as for a second laminate obtained by bonding the second adhesive surface in the adhesive sheet 1 to one surface of a resin film, a pair resin film adhesive force Fr3 at 100°C is 0.01-5 N/25 mm.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to a pressure-sensitive adhesive sheet suitable for fixing and peeling a work and a laminate using the same.

In devices such as optical members and electronic members as workpieces (workpieces), the device is fixed to the substrate (pedestal) via the adhesive layer of the adhesive sheet during processes such as processing, assembly (lamination), and inspection. to be done. After completion of the process, the work is separated from the substrate.

As the adhesive layer as described above, Patent Document 1 discloses an adhesive layer whose adhesive strength is reduced by ultraviolet irradiation under predetermined conditions. When the adhesive layer is used, the adhesive force to the work can be reduced by irradiating the adhesive layer with ultraviolet rays under predetermined conditions after the process is completed, thereby easily removing the work from the substrate. It becomes possible to peel off.

JP-A-2000-275625

By the way, in the above-described process, the work is heated while the work is fixed to the substrate via the adhesive layer, or the work is secondarily heated (hereinafter, these treatments are referred to as may be collectively referred to as “heat treatment”).

In the above heat treatment, the adhesive layer is heated together with the workpiece, and the adhesive layer subjected to such heat treatment tends to excessively improve its adhesiveness to the substrate. Therefore, in the conventional adhesive sheet disclosed in Patent Document 1, when the adhesive sheet is to be peeled off from the substrate after the process is completed and the workpiece is separated from the adhesive sheet, the adhesive sheet does not adhere to the substrate. On the other hand, there is a problem that a part of the adhesive constituting the adhesive layer of the adhesive sheet remains on the substrate because it adheres firmly to the substrate. When such problems occur, it becomes difficult to reuse the substrate.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and aims to provide a pressure-sensitive adhesive sheet that enables reuse of a substrate even when heat treatment is performed, and a laminate using the pressure-sensitive adhesive sheet. aim.

In order to achieve the above object, firstly, the present invention provides a first pressure-sensitive adhesive layer, and a pressure-sensitive adhesive that is laminated on one side of the first pressure-sensitive adhesive layer and constitutes the first pressure-sensitive adhesive layer. is a pressure-sensitive adhesive sheet comprising a second pressure-sensitive adhesive layer composed of a different pressure-sensitive adhesive, wherein the pressure-sensitive adhesive sheet is the surface of the first pressure-sensitive adhesive layer opposite to the second pressure-sensitive adhesive layer and has a second adhesive surface as a surface opposite to the first adhesive layer in the second adhesive layer, and the first adhesive surface in the adhesive sheet The glass at 23 ° C. after heating the first laminate in which the surface is attached to one side of a glass plate at 100 ° C. for 300 minutes, and then lowering the temperature of the first laminate to 23 ° C. The pressure-sensitive adhesive sheet has an adhesive force F _g2 to glass of 0.1 N/25 mm or more and 7 N/25 mm or less, and the second pressure-sensitive adhesive surface of the pressure-sensitive adhesive sheet is bonded to one side of a resin film. With respect to the laminate of 2, the pressure-sensitive adhesive sheet has an adhesive force _Fr3 to the resin film at 100° C. to the resin film of 0.01 N/25 mm or more and 5 N/25 mm or less ( Invention 1).

The pressure-sensitive adhesive sheet according to the invention ( _Invention 1) includes a first pressure-sensitive _adhesive layer and a second pressure-sensitive adhesive layer. As a result, the work can be held well on the substrate during the process, and the work can be easily peeled off from the adhesive sheet after the process is completed. It can be peeled off easily. That is, according to the pressure-sensitive adhesive sheet, the substrate can be reused satisfactorily.

In the above invention (Invention 1), after heating the second laminate at 100 ° C. for 300 minutes, the temperature of the second laminate is lowered to 23 ° C., and the above-mentioned It is preferable that the pressure-sensitive adhesive sheet has a resin film adhesive strength _Fr4 of 0.01 N/25 mm or more and 10 N/25 mm or less (Invention 2).

In the above inventions (inventions 1 and 2), it is preferable that the second pressure-sensitive adhesive layer is composed of an active energy ray-curable pressure-sensitive adhesive (invention 3).

In the above invention (invention 3), regarding the first laminate, the adhesive force of the adhesive sheet to the glass plate at 23 ° C. to the glass is _Fg1 , and the second adhesive constituting the second laminate When _Fr2 is the adhesive force of the adhesive sheet to the resin film at 23° C. after the active energy ray is applied to the agent layer, the adhesive force _Fr2 relative to the adhesive force _Fg1 is: The ratio (F _r2 /F _g1 ) is preferably 0.001 or more and 10 or less (Invention 4).

In the above inventions (inventions 3 and 4), after heating the second laminate at 100 ° C. for 300 minutes, the temperature of the second laminate is lowered to 23 ° C., and the second laminate is When the adhesive force of the adhesive sheet to the resin film at 23 ° C. after irradiating the second adhesive layer to constitute the second adhesive layer with respect to the resin film is F _r5 , the adhesive force F _g2 It is preferable that the ratio (F _r5 /F _g2 ) of the adhesive force F _r5 to the above is 0.001 or more and 12 or less (Invention 5).

In the above inventions (Inventions 1 to 5), it is preferable that a core material is laminated between the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer (Invention 6).

In the above inventions (inventions 1 to 6), during the process, the first adhesive surface is attached to the substrate and the second adhesive surface is attached to the workpiece, thereby fixing the workpiece to the substrate, After completion, it is preferably used for peeling the work from the second adhesive surface (Invention 7).

In the above inventions (inventions 1 to 7), it is preferable that the application includes heating of the workpiece fixed to the substrate (invention 8).

In the above invention (invention 8), the work is preferably a flexible device (invention 9).

In the above inventions (Inventions 1 to 9), the adhesive sheet includes two release sheets, and the release surface of one of the release sheets is in contact with the first adhesive surface, and the release sheet of the other release sheet is in contact with the first adhesive surface. It is preferable that the release surface is in contact with the second adhesive surface (Invention 10).

Secondly, the present invention comprises a flexible device, the adhesive sheet (inventions 1 to 10), and a substrate laminated in that order, the second adhesive surface of the adhesive sheet being attached to the flexible device, A laminate is provided in which the first adhesive surface of the adhesive sheet is attached to the substrate (Invention 11).

According to the pressure-sensitive adhesive sheet of the present invention, the substrate can be reused even when heat treatment is performed. In addition, the laminate according to the present invention allows reuse of the substrate.

1 is a cross-sectional view of a pressure-sensitive adhesive sheet according to one embodiment of the present invention; FIG. It is a sectional view of a layered product concerning one embodiment of the present invention.

Embodiments of the present invention will be described below.
A pressure-sensitive adhesive sheet according to one embodiment of the present invention includes a first pressure-sensitive adhesive layer and a second pressure-sensitive adhesive layer laminated on one side of the first pressure-sensitive adhesive layer.

Further, the pressure-sensitive adhesive sheet according to the present embodiment has a first pressure-sensitive adhesive surface as a surface of the first pressure-sensitive adhesive layer opposite to the second pressure-sensitive adhesive layer, and the first pressure-sensitive adhesive layer of the second pressure-sensitive adhesive layer It has a second adhesive surface as the surface opposite to the adhesive layer.

The pressure-sensitive adhesive sheet according to the present embodiment fixes a device such as an optical member or an electronic member, which is a workpiece (work), to a substrate through the pressure-sensitive adhesive sheet during processes such as processing, assembly (stacking), and inspection. It is preferably used for At this time, it is preferable that the first adhesive surface of the adhesive sheet according to the present embodiment is attached to the substrate, and the second adhesive surface is attached to the workpiece. After completing the above steps, the work is separated from the substrate. Note that the above board is for supporting and fixing the workpiece during the process, and includes the concept of a pedestal and the like.

The work is not particularly limited, but flexible devices such as optical members and electronic members having flexibility are preferable. Moreover, the work may be a work including heat treatment during the above process. Such heat treatment includes, for example, a metal vapor deposition process for forming wiring of a transparent electrode, a resin curing process, and the like. From these points of view, the work is preferably a flexible organic light emitting diode (OLED) device, a flexible liquid crystal device, or the like, and particularly preferably a flexible OLED device.

The thickness of the work is not particularly limited, but it is preferably a thickness that facilitates the expression of flexibility, specifically, it is preferably 5 μm or more, more preferably 15 μm or more, and particularly 30 μm or more. It is preferably 40 μm or more, more preferably 40 μm or more. The thickness of the workpiece is preferably 5000 μm or less, more preferably 2000 μm or less, particularly preferably 1000 μm or less, and further preferably 500 μm or less.

Moreover, the planar shape of the workpiece may be circular or polygonal, preferably polygonal. When the workpiece has a polygonal shape in plan view, the total number of sides forming the polygonal shape is not particularly limited, but is preferably 3 or more, particularly preferably 4 or more. Further, the total number of sides forming the polygonal shape is preferably 10 sides or less, particularly preferably 6 sides or less. Above all, when the workpiece has a polygonal shape in plan view, it is particularly preferable that the polygonal shape is a quadrangle having four sides.

Further, when the workpiece has a polygonal shape in plan view, the lengths of the sides forming the polygonal shape may be the same length or may be different lengths. When the workpiece has a quadrangular shape in plan view, it is preferable that the opposing sides are parallel, and it is particularly preferable that the workpiece be a rectangle having long sides and short sides. In this case, the length of the long side is preferably 10 mm or longer, particularly preferably 40 mm or longer, and more preferably 80 mm or longer. The length of the long side is preferably 1500 mm or less, particularly preferably 800 mm or less, and more preferably 500 mm or less. On the other hand, the length of the short side is preferably 5 mm or longer, particularly preferably 10 mm or longer, and more preferably 20 mm or longer. Also, the length of the short side is preferably 1000 mm or less, particularly preferably 600 mm or less, and more preferably 350 mm or less.

The substrate is not particularly limited as long as the work can be fixed via the adhesive layer of the adhesive sheet. Those that do not change are preferred. In addition, the work is attached to the substrate through the adhesive layer of the adhesive sheet, but the adhesive layer and the substrate must be sufficiently fixed during the above steps and in the step of peeling off the work. . For example, if the surface of the substrate is rough, the adhesiveness between the substrate and the pressure-sensitive adhesive layer is reduced, which may cause the problem that the pressure-sensitive adhesive layer peels off from the substrate during the process. Therefore, it is preferable that the surface of the substrate on the work fixing side is smooth. From these points of view, the substrate is preferably a glass substrate.

In the adhesive sheet according to the present embodiment, after heating the first laminate obtained by bonding the first adhesive surface of the adhesive sheet to one side of the glass plate at 100 ° C. for 300 minutes, the first laminate After the temperature is lowered to 23°C, the pressure-sensitive adhesive sheet has a glass adhesive force _Fg2 to a glass plate at 23°C of 0.1 N/25 mm or more and 7 N/25 mm or less.

Furthermore, in the pressure-sensitive adhesive sheet according to the present embodiment, regarding the second laminate obtained by bonding the second pressure-sensitive adhesive surface of the pressure-sensitive adhesive sheet to one side of the resin film, the pressure-sensitive adhesive sheet with respect to the resin film at 100 ° C. Adhesive force _Fr3 is 0.01 N/25 mm or more and 5 N/25 mm or less.

In the pressure-sensitive adhesive sheet according to the present embodiment, the adhesive force F _g2 to glass described above is within the above range, and the adhesive force F _r3 to resin film is within the above-described range, so that the workpiece is fixed to the substrate via the pressure-sensitive adhesive sheet. Even if the pressure-sensitive adhesive sheet is subjected to heat treatment in this state, the pressure-sensitive adhesive sheet after separating the work can be easily peeled off from the substrate. Moreover, such an effect is achieved without impairing the effect of holding the workpiece on the substrate during the process and the effect of easily peeling the workpiece from the adhesive sheet after the process is completed. Therefore, according to the pressure-sensitive adhesive sheet according to the present embodiment, even when the heat treatment described above is performed, the process can be performed satisfactorily, and the substrate can be satisfactorily reused.

If the above-described adhesive force to glass _Fg2 is less than 0.1 N/25 mm, the adhesive sheet will peel off from the substrate after the heat treatment, making it impossible to carry out the process satisfactorily. Further, if the above-described adhesive force to glass _Fg2 exceeds 7 N/25 mm, it becomes difficult to remove the adhesive sheet from the substrate satisfactorily, and the substrate cannot be reused. From the above point of view, the adhesive strength to glass _Fg2 described above is preferably 0.15 N/25 mm or more, and particularly preferably 0.2 N/25 mm or more. Further, the adhesive strength to glass _Fg2 described above is preferably 6 N/25 mm or less, and particularly preferably 5.5 N/25 mm or less.

When the adhesive force _Fr3 to the resin film is less than 0.01 N/25 mm, the workpiece is separated from the adhesive sheet during heat treatment, and the process cannot be carried out satisfactorily. Further, if the adhesive force _Fr3 to the resin film exceeds 5 N/25 mm, the workpiece cannot be easily separated from the adhesive sheet after the process is completed. From the above point of view, the adhesive force F _r3 to the resin film is preferably 0.1 N/25 mm or more, particularly preferably 0.5 N/25 mm or more, and further preferably 0.8 N/25 mm or more. is preferred. In addition, the adhesive strength _Fr3 to the resin film described above is preferably 3 N/25 mm or less, particularly preferably 2 N/25 mm or less, and further preferably 1.8 N/25 mm or less.

In the pressure-sensitive adhesive sheet according to the present embodiment, for the first laminate described above, the adhesive force F _g1 of the pressure-sensitive adhesive sheet to the glass plate described above at 23 ° C. is preferably 0.01 N/25 mm or more, particularly It is preferably 0.05 N/25 mm or more, more preferably 0.1 N/25 mm or more. As a result, the pressure-sensitive adhesive sheet exhibits better adhesion to the substrate, and the pressure-sensitive adhesive sheet can be easily held on the substrate during the process. Further, the adhesion force to glass F _g1 is preferably 10 N/25 mm or less, particularly preferably 7 N/25 mm or less, and further preferably 5 N/25 mm or less. This makes it possible to more effectively separate the adhesive sheet from the substrate after the completion of the process.

In the pressure-sensitive adhesive sheet according to the present embodiment, for the above-described second laminate, the pressure-sensitive adhesive sheet to the resin film described above at 23° C. preferably has a resin film adhesive strength F _r1 of 0.1 N/25 mm or more, In particular, it is preferably 1 N/25 mm or more, more preferably 2 N/25 mm or more. As a result, the adhesive sheet exhibits better adhesiveness to the work, and the work can be easily held on the substrate via the adhesive sheet during the process. In addition, the adhesive force F _r1 to the resin film is preferably 7 N/25 mm or less, more preferably 5 N/25 mm or less, particularly preferably 4 N/25 mm or less, and further preferably 3 N/25 mm or less. Preferably. This makes it easier to separate the workpiece from the adhesive sheet after the process is completed.

In the pressure-sensitive adhesive sheet according to this embodiment, the second pressure-sensitive adhesive layer may be composed of an active energy ray-curable pressure-sensitive adhesive, as will be described later. In this case, the adhesive force F _r2 of the adhesive sheet to the resin film described above at 23 ° C. after irradiating the second adhesive layer constituting the second laminate described above with the active energy ray is , preferably 0.01 N/25 mm or more, more preferably 0.03 N/25 mm or more, particularly preferably 0.05 N/25 mm or more, further preferably 0.06 N/25 mm or more is preferred. This makes it possible to separate the workpiece from the adhesive sheet more easily by irradiating the active energy ray. Further, the adhesion force _Fr2 to the resin film is preferably 1 N/25 mm or less, particularly preferably 0.5 N/25 mm or less, further preferably 0.1 N/25 mm or less. This makes it easier to prevent the work from unintentionally moving on the adhesive sheet or falling off the adhesive sheet after being irradiated with the active energy ray.

In the pressure-sensitive adhesive sheet according to the present embodiment, after heating the above-described second laminate at 100 ° C. for 300 minutes, the temperature of the second laminate is lowered to 23 ° C., and the above-described resin at 23 ° C. The adhesion force F _r4 of the adhesive sheet to the film to the resin film is preferably 0.01 N/25 mm or more, more preferably 0.1 N/25 mm or more, and particularly preferably 1 N/25 mm or more, Furthermore, it is preferably 3 N/25 mm or more, most preferably 4 N/25 mm or more. Also, the adhesion force _Fr4 to the resin film is preferably 10 N/25 mm or less, particularly preferably 8 N/25 mm or less, and further preferably 7 N/25 mm or less. When the adhesive force F _r4 to the resin film is 0.01 N/25 mm or more, the adhesive sheet exhibits sufficient adhesiveness to the work even when heat treatment is performed, and the process is improved. It becomes easy to go to. When the adhesive force _Fr4 to the resin film is 10 N/25 mm or less, the workpiece can be easily separated from the adhesive sheet even when heat treatment is performed.

In the pressure-sensitive adhesive sheet according to the present embodiment, when the second pressure-sensitive adhesive layer is composed of an active energy ray-curable pressure-sensitive adhesive, after heating the above-described second laminate at 100 ° C. for 300 minutes, The temperature of the laminate in No. 2 is lowered to 23 ° C., and the adhesive sheet for the resin film at 23 ° C. after irradiating the second adhesive layer constituting the second laminate with an active energy ray. The adhesion force _Fr5 to the resin film is preferably 0.01 N/25 mm or more, more preferably 0.05 N/25 mm or more, particularly preferably 0.1 N/25 mm or more, and further preferably 0.01 N/25 mm or more. .15 N/25 mm or more is preferable. As a result, even when heat treatment is performed, it is easy to prevent the workpiece from moving unintentionally on the adhesive sheet or falling off the adhesive sheet after the active energy ray irradiation. In addition, the adhesion force F _r5 to the resin film is preferably 5 N/25 mm or less, more preferably 1 N/25 mm or less, particularly preferably 0.5 N/25 mm or less, and further preferably 0.3 N. /25 mm or less. Thereby, even if heat treatment is performed, the work can be more easily separated from the adhesive sheet by irradiating the work with active energy rays.

In the pressure-sensitive adhesive sheet according to the present embodiment, the ratio (F _g2 /F _g1 ) of the above-described adhesive force F _g2 to the above-described adhesive force F _g1 is preferably 0.9 or more, particularly 1.1 or more. is preferred, and more preferably 1.3 or more. Also, the ratio (F _g2 /F _g1 ) is preferably 5 or less, more preferably 4 or less, particularly preferably 3 or less, further preferably 2 or less. When the ratio (F _g2 /F _g1 ) is within the above range, even when heat treatment is performed, excessive decrease or increase in adhesive strength can be prevented, and the substrate and the work can be fixed well. .

In the pressure-sensitive adhesive sheet according to the present embodiment, the ratio (F _r4 /F _r1 ) of the above-described adhesive force F _r4 to the above-described adhesive force F _r1 is preferably 0.9 or more, particularly 1.1 or more. is preferred, and more preferably 1.3 or more. Also, the ratio (F _r4 /F _r1 ) is preferably 5 or less, more preferably 4 or less, particularly preferably 3 or less, further preferably 2 or less. When the ratio (F _r4 /F _r1 ) is within the above range, even when heat treatment is performed, excessive decrease or increase in adhesive strength can be prevented, and the substrate and the work can be fixed well. .

In the pressure-sensitive adhesive sheet according to the present embodiment, the ratio (F _r5 /F _r4 ) of the above-described adhesive force F _r5 to the above-described adhesive force F _r4 is preferably 0.001 or more, particularly 0.01 or more. is preferred, and more preferably 0.015 or more. In addition, the ratio (F _r5 /F _r4 ) is preferably 1 or less, more preferably 0.5 or less, particularly preferably 0.1 or less, and further preferably 0.06 or less. is preferred. When the ratio (F _r5 /F _r4 ) is within the above range, even if the adhesive sheet is subjected to heat treatment, after irradiating the adhesive sheet with active energy rays, when separating the work from the adhesive sheet , the workpiece can be easily separated while the adhesive sheet is well held on the substrate.

In the pressure-sensitive adhesive sheet according to the present embodiment, the ratio (F _r1 /F _g1 ) of the above-described adhesive force F _r1 to the above-described adhesive force F _g1 is preferably 0.1 or more, particularly 0.4 or more. is preferred, and more preferably 0.8 or more. Also, the ratio (F _r1 /F _g1 ) is preferably 100 or less, more preferably 75 or less, particularly preferably 50 or less, further preferably 35 or less. When the ratio (F _r1 /F _g1 ) is within the above range, the substrate and the work can be satisfactorily fixed.

In the pressure-sensitive adhesive sheet according to the present embodiment, the ratio (F _r2 /F _g1 ) of the above-described adhesive force F _r2 to the above-described adhesive force F _g1 is preferably 0.001 or more, and preferably 0.005 or more. is more preferably 0.01 or more, and more preferably 0.02 or more. As a result, when separating the workpiece from the adhesive sheet after irradiating the adhesive sheet with active energy rays, the adhesive sheet can be prevented from moving unintentionally on the adhesive sheet or falling off the adhesive sheet. It becomes easy to ensure the ease of peeling from the substrate. Also, the ratio (F _r2 /F _g1 ) is preferably 10 or less, particularly preferably 5 or less, further preferably 1 or less. As a result, when separating the work from the adhesive sheet after irradiating the adhesive sheet with active energy rays, the work can be easily separated while the adhesive sheet is well held on the substrate.

In the pressure-sensitive adhesive sheet according to the present embodiment, the ratio (F _r4 /F _g2 ) of the above-described adhesive force F _r4 to the above-described adhesive force F _g2 is preferably 0.1 or more, and is 0.5 or more. is more preferably 1 or more, and more preferably 1.2 or more. Also, the ratio (F _r4 /F _g2 ) is preferably 100 or less, more preferably 75 or less, particularly preferably 50 or less, further preferably 30 or less. When the ratio (F _r4 /F _g2 ) is within the above range, the substrate and the work can be satisfactorily fixed even when heat treatment is performed.

In the pressure-sensitive adhesive sheet according to the present embodiment, the ratio (F _r5 /F _g2 ) of the above-described adhesive force F _r5 to the above-described adhesive force F _g2 is preferably 0.001 or more, and is 0.01 or more. is more preferably 0.02 or more, and more preferably 0.04 or more. Even if the adhesive sheet has been subjected to heat treatment, it prevents the workpiece from moving unintentionally on the adhesive sheet or falling off the adhesive sheet when separating the workpiece from the adhesive sheet after irradiating the adhesive sheet with active energy rays. However, it becomes easy to secure the ease of peeling the adhesive sheet from the substrate. Also, the ratio (F _r5 /F _g2 ) is preferably 12 or less, particularly preferably 6 or less, further preferably 2 or less. As a result, even if the adhesive sheet has been subjected to heat treatment, when the adhesive sheet is separated from the adhesive sheet after being irradiated with active energy rays, the adhesive sheet can be held well on the substrate and the workpiece can be easily removed. becomes easier to separate into

The adhesive force F _g1 , adhesive force F _g2 , adhesive force F _r1 , adhesive force F _r2 , adhesive force F _r3 , adhesive force F _r4 , and adhesive force F _r5 described above are basically defined in JIS Z0237:2009. The adhesive strength is measured by the 180-degree peeling method according to the standard, and the details of these measuring methods are as described in the test examples described later.

FIG. 1 shows a specific configuration as an example of the pressure-sensitive adhesive sheet according to this embodiment.
As shown in FIG. 1, the pressure-sensitive adhesive sheet 1 according to one embodiment includes a first pressure-sensitive adhesive layer 111, a second pressure-sensitive adhesive layer 112 laminated on one side of the first pressure-sensitive adhesive layer 111, A core material 113 laminated between the first adhesive layer 111 and the second adhesive layer 112 is provided. Furthermore, the pressure-sensitive adhesive sheet 1 according to the present embodiment includes a release sheet 12a laminated on the opposite side of the first pressure-sensitive adhesive layer 111 to the second pressure-sensitive adhesive layer 112, and the first pressure-sensitive adhesive layer 112 on the second pressure-sensitive adhesive layer 112. and a release sheet 12b laminated on the side opposite to the pressure-sensitive adhesive layer 111. Here, the release surface of release sheet 12a is in contact with the first adhesive surface, and the release surface of release sheet 12b is in contact with the second adhesive surface. In this specification, the release surface of the release sheet refers to the surface of the release sheet that has releasability, and includes both the surface that has been subjected to a release treatment and the surface that exhibits releasability without being subjected to a release treatment. .

1. Each member 1-1. First adhesive layer The adhesive constituting the first adhesive layer 111 is not particularly limited as long as the glass adhesive strength F _g2 and the resin film adhesive strength F _r3 are within the ranges described above. . Examples of the type of adhesive that constitutes the first adhesive layer 111 include acrylic adhesives, silicone adhesives, polyester adhesives, polyurethane adhesives, rubber adhesives, and the like. good. The adhesive may be emulsion type, solvent type or non-solvent type, and may be crosslinked or non-crosslinked. Among them, an acrylic pressure-sensitive adhesive or a silicone pressure-sensitive adhesive that easily achieves the above-described adhesive strength (particularly, the adhesive strength to glass F _g2 ) is preferable.

(1) Acrylic Adhesive The acrylic adhesive constituting the first adhesive layer 111 may be active energy ray-curable or non-active energy ray-curable. good.

Here, as will be described later, when using an active energy ray-curable adhesive as the adhesive constituting the second adhesive layer 112, the second adhesive layer 112 is irradiated with an active energy ray. As a result, the adhesive force to the adherend on the side of the second adhesive layer 112 can be favorably reduced. This makes it easier to separate the workpiece from the adhesive sheet 1 after the completion of the process. At this time, on the side of the first adhesive layer 111, even if the adhesive force to the substrate is maintained and the work is separated, the adhesive sheet 1 may be peeled off from the substrate or the adhesive sheet 1 may move on the substrate. preferably not. That is, when the adhesive sheet 1 is irradiated with active energy rays, the adhesive strength of the second adhesive layer 112 side is reduced, but the adhesive strength of the first adhesive layer 111 side is preferably not reduced. From this point of view, it is preferable that the acrylic pressure-sensitive adhesive constituting the first pressure-sensitive adhesive layer 111 is non-curable with active energy rays.

The active energy ray non-curable acrylic pressure-sensitive adhesive is formed from a pressure-sensitive adhesive composition containing an acrylic copolymer and a cross-linking agent (hereinafter sometimes referred to as "adhesive composition P1"). It is preferably an adhesive (an adhesive obtained by cross-linking the adhesive composition P1). The concept of "copolymer" is also included in "polymer".

(1-1) Acrylic copolymer The above acrylic copolymer may contain a structural unit derived from a functional group-containing monomer and a structural unit derived from a (meth)acrylic acid alkyl ester monomer or a derivative thereof. preferable. In this specification, (meth)acrylic acid means both acrylic acid and methacrylic acid. The same applies to other similar terms.

The functional group-containing monomer as a structural unit of the acrylic copolymer is a monomer having a polymerizable double bond and a functional group such as a hydroxyl group, a carboxyl group, an amino group, a substituted amino group, an epoxy group, etc. in the molecule. is preferably The functional group possessed by the functional group-containing monomer is used in the reaction between the acrylic copolymer and the cross-linking agent, and when the reaction occurs, a cross-linked structure (three-dimensional network structure) is formed in the adhesive, resulting in desired aggregation. power is achieved.

Examples of hydroxy group-containing monomers include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, ( 3-Hydroxybutyl meth)acrylate, 4-hydroxybutyl (meth)acrylate and the like can be mentioned, and these can be used alone or in combination of two or more. Among the above, 4-hydroxybutyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate and 2-hydroxypropyl (meth)acrylate are used from the viewpoint that the reaction with the cross-linking agent proceeds favorably. It is particularly preferred to use 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate and 4-hydroxybutyl acrylate.

Carboxy group-containing monomers include, for example, ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, and citraconic acid. These may be used alone or in combination of two or more. Among those mentioned above, it is preferable to use acrylic acid from the viewpoint that the reaction with the cross-linking agent proceeds favorably.

Examples of amino group-containing monomers or substituted amino group-containing monomers include aminoethyl (meth)acrylate and n-butylaminoethyl (meth)acrylate. These may be used alone or in combination of two or more.

The acrylic copolymer preferably contains 0.1% by mass or more, and preferably 0.4% by mass or more, of a structural unit derived from the functional group-containing monomer as a monomer unit constituting the polymer. is more preferable, particularly preferably 1% by mass or more, and more preferably 2% by mass or more. In addition, the acrylic copolymer preferably contains 12% by mass or less, particularly 8% by mass or less, of structural units derived from the functional group-containing monomer as monomer units constituting the polymer. Preferably, it is contained in an amount of 5% by mass or less. When the acrylic copolymer contains the monomer units constituting the polymer within the above range, it has a desired cohesive force and facilitates the formation of a pressure-sensitive adhesive exhibiting the above-described adhesive physical properties.

As the (meth)acrylic acid alkyl ester monomer as a structural unit of the acrylic copolymer, a (meth)acrylic acid alkyl ester monomer having an alkyl group having 1 to 20 carbon atoms is preferable. Alkyl groups may be linear or branched, or may have a cyclic structure.

The (meth)acrylic acid alkyl ester monomer having an alkyl group having 1 to 20 carbon atoms is particularly a (meth)acrylic acid alkyl ester monomer having an alkyl group having 1 to 18 carbon atoms, such as (meth)acrylic acid. It is preferable to use methyl, ethyl (meth)acrylate, propyl (meth)acrylate, etc., and it is particularly preferable to use methyl acrylate. These may be used individually by 1 type, and may be used in combination of 2 or more type.

In addition, the (meth)acrylic acid alkyl ester monomer having an alkyl group having 1 to 20 carbon atoms has a glass transition temperature (Tg) of −30° C. or less as a homopolymer (hereinafter referred to as “low Tg alkyl acrylate” It is also preferable to contain. By containing such a low Tg alkyl acrylate as a constituent monomer unit, the pressure-sensitive adhesive obtained easily exhibits suitable viscoelasticity, and not only in a room temperature environment but also when the pressure-sensitive adhesive is exposed to high temperatures. Also, it becomes easy to achieve the desired adhesive strength.

Low Tg alkyl acrylates include, for example, n-butyl acrylate (Tg-55°C), n-octyl acrylate (Tg-65°C), isooctyl acrylate (Tg-58°C), 2-ethylhexyl acrylate (Tg -70°C), isononyl acrylate (Tg-58°C), isodecyl acrylate (Tg-60°C), isodecyl methacrylate (Tg-41°C), n-lauryl methacrylate (Tg-65°C), tridecyl acrylate (Tg-55°C), tridecyl methacrylate (Tg-40°C) and the like are preferred. Among them, the low Tg alkyl acrylate is more preferably one having a homopolymer Tg of -45°C or lower, particularly preferably -50°C or lower. Specifically, n-butyl acrylate and 2-ethylhexyl acrylate are particularly preferred. These may be used alone or in combination of two or more.

When two or more types of low-Tg alkyl acrylates are used in combination, it is preferable that the content of the low-Tg alkyl acrylate having the lowest Tg among the low-Tg alkyl acrylates to be used is large, from the viewpoint that the workpiece can be easily separated from the substrate after the process is completed. .

The acrylic copolymer preferably contains 80% by mass or more, more preferably 88% by mass or more, and particularly 90% by mass or more of a low-Tg alkyl acrylate as a monomer unit constituting the polymer. preferably, more preferably 95% by mass or more. In addition, the acrylic copolymer preferably contains 99.9% by mass or less, particularly preferably 99% by mass or less, of a low-Tg alkyl acrylate as a monomer unit constituting the polymer. It is preferable to contain 98% by mass or less. When the content of the low-Tg alkyl acrylate is within the above range, it becomes easy to form a pressure-sensitive adhesive that has desired cohesive strength and exhibits the above-described pressure-sensitive adhesive physical properties.

If desired, the acrylic copolymer may contain other monomers as monomer units constituting the polymer. Such monomers include, for example, monomers having an alicyclic structure in the molecule (alicyclic structure-containing monomers), non-reactive nitrogen atom-containing monomers such as N-acryloylmorpholine and N-vinyl-2-pyrrolidone, ( (Meth)acrylic acid alkoxyalkyl esters such as methoxyethyl methacrylate and ethoxyethyl (meth)acrylate, vinyl acetate, styrene, and the like. These may be used alone or in combination of two or more.

The acrylic copolymer is preferably a solution polymer obtained by a solution polymerization method. Since it is a solution polymer, a high-molecular-weight polymer can be easily obtained, and a pressure-sensitive adhesive that easily satisfies the above-described adhesive properties can be obtained.

The polymerization mode of the acrylic copolymer may be a random copolymer or a block copolymer.

The weight average molecular weight (Mw) of the acrylic copolymer thus obtained is preferably 100,000 or more, more preferably 200,000 or more, and particularly preferably 300,000 or more. is preferably 400,000 or more. Also, the weight average molecular weight (Mw) is preferably 1,500,000 or less, particularly preferably 1,200,000 or less, and more preferably 900,000 or less. In addition, the weight average molecular weight (Mw) in this specification is the value of standard polystyrene conversion measured by the gel permeation chromatography method (GPC method).

(1-2) Cross-linking agent The cross-linking agent cross-links the acrylic copolymer to form a three-dimensional network structure triggered by heating of the adhesive composition P1 containing the cross-linking agent. Thereby, the cohesion force of the obtained adhesive is improved, and the adhesive force becomes higher.

The above-mentioned cross-linking agent may be one that reacts with the functional group of the acrylic copolymer. Examples include hydrazine-based cross-linking agents, aldehyde-based cross-linking agents, oxazoline-based cross-linking agents, metal alkoxide-based cross-linking agents, metal chelate-based cross-linking agents, metal salt-based cross-linking agents, and ammonium salt-based cross-linking agents. Here, when the acrylic copolymer contains a hydroxy group-containing monomer as a constituent monomer unit, it is preferable to use an isocyanate-based cross-linking agent having excellent reactivity with hydroxy groups as the cross-linking agent. In addition, a crosslinking agent can be used individually by 1 type or in combination of 2 or more types.

The isocyanate-based cross-linking agent contains at least a polyisocyanate compound. Examples of polyisocyanate compounds include aromatic polyisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate and xylylene diisocyanate, aliphatic polyisocyanates such as hexamethylene diisocyanate, and alicyclic polyisocyanates such as isophorone diisocyanate and hydrogenated diphenylmethane diisocyanate. , and their biuret, isocyanurate, and adducts which are reaction products with low-molecular-weight active hydrogen-containing compounds such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, and castor oil. Among them, aliphatic isocyanates having hexamethylene diisocyanate, trimethylolpropane-modified tolylene diisocyanate, and the like are preferably used from the viewpoint of reactivity with hydroxyl groups.

The content of the cross-linking agent in the adhesive composition P1 is preferably 0.01 parts by mass or more, and preferably 0.1 parts by mass or more, relative to 100 parts by mass of the acrylic copolymer described above. It is more preferably 1 part by mass or more, and more preferably 2 parts by mass or more. Also, the content is preferably 10 parts by mass or less, particularly preferably 8 parts by mass or less, and further preferably 7 parts by mass or less. When the content of the cross-linking agent is within the above range, the pressure-sensitive adhesive to be obtained easily satisfies the pressure-sensitive adhesive physical properties described above.

(1-3) Various Additives The adhesive composition P1 may optionally contain various additives commonly used in acrylic adhesives, such as silane coupling agents, ultraviolet absorbers, curing retarders, and tackifiers. , antioxidants, light stabilizers, softeners, fillers and the like can be added.

Fillers include inorganic microparticles such as silica, calcium carbonate, aluminum hydroxide, magnesium hydroxide, clay, talc, and titanium dioxide; organic translucent microparticles such as acrylic resins, polystyrene resins, polyethylene resins, and epoxy resins. fine particles composed of a silicon-containing compound having an intermediate structure between inorganic and organic, such as silicone resin (for example, Tospearl series manufactured by Momentive Performance Materials Japan); Among them, the filler is preferably acrylic resin fine particles and fine particles made of a silicon-containing compound having an intermediate structure between inorganic and organic, particularly inorganic and inorganic, from the viewpoint that the obtained adhesive can easily exhibit the adhesive properties described above. Microparticles composed of silicon-containing compounds having an organic intermediate structure are preferred. These may be used individually by 1 type, and may be used in combination of 2 or more type.

As for the particle shape of the filler, spherical fine particles are preferable from the viewpoint that the pressure-sensitive adhesive to be obtained easily exhibits the above-described adhesive physical properties. The lower limit of the average particle diameter of the filler is preferably 1 μm or more, particularly preferably 2 μm or more, and more preferably 3 μm or more. The upper limit of the average particle size of the filler is preferably 10 µm or less, particularly preferably 7 µm or less, and more preferably 5 µm or less. When the average particle diameter of the filler is within the above range, the resulting pressure-sensitive adhesive tends to exhibit the above-described pressure-sensitive adhesive physical properties. The average particle size of particles can be measured as an arithmetic mean value using a laser analyzer or the like in accordance with JIS Z8825:2013.

The content of the filler in the adhesive composition P1 is preferably 1 part by mass or more, particularly preferably 4 parts by mass or more, relative to 100 parts by mass of the acrylic copolymer described above. is preferably 8 parts by mass or more. Also, the content is preferably 30 parts by mass or less, particularly preferably 20 parts by mass or less, and further preferably 12 parts by mass or less. When the content of the filler is within the above range, the resulting pressure-sensitive adhesive easily satisfies the pressure-sensitive adhesive physical properties described above.

Examples of curing retarders include acetylene compounds such as ethynyl alcohol, 2-propyn-1-ol, 2-methyl-3-butyn-2-ol, 3-trimethylsiloxypropyne, N, N, N', N '-tetramethylethylenediamine, N,N-dimethylethylenediamine, N,N-diethylethylenediamine, N,N-dibutylethylenediamine, N,N-dibutyl-1,3-propanediamine, N,N-dimethyl-1,3- Propanediamine, N,N,N',N'-tetraethylethylenediamine, N,N-dibutyl-1,4-butanediamine, amine compounds such as 2,2'-bipyridine, 1,2-diesters such as dimethylmalate system compounds and the like. These may be used individually by 1 type, and may be used in combination of 2 or more type.

The content of the curing retarder in the adhesive composition P1 is preferably 0.1 parts by mass or more, particularly preferably 1 part by mass or more, relative to 100 parts by mass of the acrylic copolymer. Furthermore, it is preferably 3 parts by mass or more. Also, the content is preferably 18 parts by mass or less, particularly preferably 12 parts by mass or less, and further preferably 6 parts by mass or less.

As the silane coupling agent, an organosilicon compound having at least one alkoxysilyl group in the molecule and having good compatibility with the acrylic copolymer is preferable. When a glass substrate is used as a substrate for fixing a work, the use of a silane coupling agent makes it easier for the resulting pressure-sensitive adhesive to exhibit high adhesion to the substrate. With this improvement in adhesion to the substrate, it becomes easier to separate the workpiece from the second adhesive layer 112 in a state in which the first adhesive layer 111 is in close contact with the substrate.

Further, the silane coupling agent includes at least one selected from a vinyl group, an epoxy group, a styryl group, an acryloyl group, a methacryloyl group, an amino group, a ureido group, an isocyanate group, an isocyanurate group, a mercapto group, a methyl group and a thiol group. It is preferred to use those with one type of functional group. Among these, from the viewpoint of improving adhesion, it is preferable to use a silane coupling agent containing at least one functional group of an epoxy group and a mercapto group.

Preferred examples of silane coupling agents include polymerizable unsaturated group-containing silicon compounds such as vinyltrimethoxysilane, vinyltriethoxysilane, methacryloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 2-( 3,4-epoxycyclohexyl)ethyltrimethoxysilane, silicon compounds having an epoxy structure such as 8-glycidoxyoctyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyl Mercapto group-containing silicon compounds such as dimethoxymethylsilane, 3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyl Amino group-containing silicon compounds such as dimethoxysilane, 3-chloropropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, or at least one of these, methyltriethoxysilane, ethyltriethoxysilane, methyltrimethoxysilane, and ethyltriethoxysilane Examples include condensates with alkyl group-containing silicon compounds such as methoxysilane. These may be used individually by 1 type, and may be used in combination of 2 or more type.

The content of the silane coupling agent in the adhesive composition P1 is preferably 0.01 parts by mass or more, particularly 0.05 parts by mass or more, relative to 100 parts by mass of the acrylic copolymer. is preferred, and more preferably 0.1 parts by mass or more. In addition, the content is preferably 1 part by mass or less, particularly preferably 0.8 parts by mass or less, and further preferably 0.6 parts by mass or less.

(1-4) Production of Adhesive Composition P1 The adhesive composition P1 can be produced by mixing an acrylic copolymer, a cross-linking agent, and optionally other additives. Further, if desired, a diluent solvent may be added to the adhesive composition P1 and thoroughly mixed to obtain an adhesive composition P1 (coating solution) diluted with a solvent.

In any of the above components, if a solid one is used, or if precipitation occurs when mixed with other components in an undiluted state, the component is added alone in advance to a dilution solvent. It may be dissolved or diluted prior to mixing with other ingredients.

Examples of the diluting solvent include aliphatic hydrocarbons such as hexane, heptane and cyclohexane; aromatic hydrocarbons such as toluene and xylene; halogenated hydrocarbons such as methylene chloride and ethylene chloride; Alcohols such as 1-methoxy-2-propanol, ketones such as acetone, methyl ethyl ketone, 2-pentanone, isophorone and cyclohexanone, esters such as ethyl acetate and butyl acetate, and cellosolve solvents such as ethyl cellosolve are used.

The concentration/viscosity of the coating solution thus prepared is not particularly limited as long as it is within a range that allows coating, and can be appropriately selected according to the situation. For example, the adhesive composition P1 is diluted to a concentration of 10 to 60% by mass. When obtaining the coating solution, the addition of a diluent solvent or the like is not a necessary condition, and the diluent solvent may not be added as long as the viscosity of the adhesive composition P1 allows coating.

(1-5) Formation of First Adhesive Layer The first adhesive layer 111 can be formed by crosslinking the applied adhesive composition P1. Crosslinking of the adhesive composition P1 is preferably performed by heat treatment. Note that this heat treatment can also serve as a drying treatment after the application of the adhesive composition P1.

The heating temperature of the heat treatment is preferably 50 to 150.degree. Also, the heating time is preferably 10 seconds to 10 minutes. It is also preferable to provide a curing period of about 1 to 2 weeks at room temperature (eg, 23° C., 50% RH) after the heat treatment.

By the above heat treatment (and curing), the acrylic copolymer is satisfactorily crosslinked via the crosslinking agent.

(1-6) Thickness of the first adhesive layer When the first adhesive layer 111 is composed of an acrylic adhesive, the thickness of the first adhesive layer 111 (JIS K7130: 1999) is preferably 5 μm or more, particularly preferably 10 μm or more, further preferably 15 μm or more as a lower limit. When the lower limit value of the thickness of the first pressure-sensitive adhesive layer 111 is above, the adhesive strength is further improved. The upper limit of the thickness of the first pressure-sensitive adhesive layer 111 is preferably 50 μm or less, particularly preferably 40 μm or less, further preferably 30 μm or less. When the upper limit value of the thickness of the first pressure-sensitive adhesive layer 111 is above, the easy peeling property becomes more excellent. The first adhesive layer 111 made of an acrylic adhesive may be formed as a single layer, or may be formed by laminating a plurality of layers.

(2) Silicone-Based Adhesive The silicone-based adhesive preferably contains (a cured product of) an organopolysiloxane, particularly an addition-type organopolysiloxane. Such a silicone-based pressure-sensitive adhesive easily satisfies the adhesive strength described above, and is also excellent in workability.

The addition type organopolysiloxane is preferably obtained by reacting an organohydrogenpolysiloxane with an organopolysiloxane having a siloxane bond as a main skeleton and having an alkenyl group.

Organopolysiloxane having a siloxane bond as a main skeleton and having alkenyl groups is preferably a compound represented by the following average unit formula (1) and having at least two alkenyl groups in the molecule.
R ¹ _a SiO _(4-a)/2 (1)
(wherein R ¹ is the same or different unsubstituted or substituted monovalent hydrocarbon group having 1 to 12 carbon atoms, preferably 1 to 8 carbon atoms, a is 1.5 to 2.8, preferably 1 .8 to 2.5, more preferably a positive number in the range of 1.95 to 2.05.)

Examples of the unsubstituted or substituted monovalent hydrocarbon group bonded to the silicon atom represented by R ¹ include vinyl group, allyl group, propenyl group, isopropenyl group, butenyl group, hexenyl group, cyclohexenyl group, octenyl alkenyl group, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, cyclohexyl group, octyl group, nonyl group, decyl group, etc. Alkyl groups, phenyl groups, tolyl groups, xylyl groups, aryl groups such as naphthyl groups, aralkyl groups such as benzyl groups, phenylethyl groups and phenylpropyl groups, and some or all of the hydrogen atoms of these groups are fluorine, Examples thereof include those substituted with halogen atoms such as bromine and chlorine, cyano groups and the like, such as chloromethyl, chloropropyl, bromoethyl, trifluoropropyl and cyanoethyl groups. As the alkenyl group, a vinyl group is preferable from the viewpoint of short curing time and productivity.

Organohydrogenpolysiloxane has SiH groups in the molecule. When the alkenyl groups of the organopolysiloxane and the SiH groups of the organohydrogenpolysiloxane react with each other, they undergo an addition reaction to give an addition-type organopolysiloxane.

The addition-type organopolysiloxane cures satisfactorily in the presence of a platinum catalyst, so the silicone pressure-sensitive adhesive preferably contains a platinum catalyst. Examples of platinum catalysts include platinum black, platinum chloride, chloroplatinic acid, reaction products of chloroplatinic acid and monohydric alcohols, complexes of chloroplatinic acid and olefins, and platinum bisacetoacetate. .

The content of the platinum catalyst in the silicone pressure-sensitive adhesive is preferably 0.01 parts by mass or more, particularly preferably 0.05 parts by mass or more, relative to 100 parts by mass of addition type organopolysiloxane. . The above content is preferably 3 parts by mass or less, particularly preferably 2 parts by mass or less, per 100 parts by mass of addition type organopolysiloxane. When the content of the platinum catalyst is within the above range, the addition-type organopolysiloxane can be cured to form the first pressure-sensitive adhesive layer 111 without interfering with coating.

The addition-type organopolysiloxane may contain an organopolysiloxane (silicone resin) containing trifunctional or tetrafunctional siloxane units in the molecule from the viewpoint of increasing adhesive strength.

When the silicone resin is used, the content of the silicone resin in the silicone pressure-sensitive adhesive is preferably more than 0 parts by mass, and is 5 parts by mass or more with respect to 100 parts by mass of addition type organopolysiloxane. is preferably 10 parts by mass or more, and more preferably 15 parts by mass or more. The above content is preferably 100 parts by mass or less, particularly preferably 50 parts by mass or less, further preferably 30 parts by mass or less with respect to 100 parts by mass of addition type organopolysiloxane. preferable. When the content of the silicone resin is within the above range, it becomes easy to achieve both excellent adhesiveness and excellent easy peelability.

If desired, the silicone-based pressure-sensitive adhesive for forming the first pressure-sensitive adhesive layer 111 may contain various additives commonly used in silicone-based pressure-sensitive adhesives, such as silane coupling agents, ultraviolet absorbers, curing retarders, Tackifiers, antioxidants, light stabilizers, softeners, fillers and the like can be added. Specific examples of these and the amount of addition when using the additive are the same as those described above.

In order to form the first pressure-sensitive adhesive layer 111 with a silicone-based pressure-sensitive adhesive, for example, an addition-type organopolysiloxane, optionally containing a trifunctional or tetrafunctional siloxane unit, and a platinum catalyst are combined. , methyl ethyl ketone, toluene, ethyl acetate, xylene, or the like, is diluted to about 10 to 60% by mass, is applied to an object to be applied (for example, the core material 113 or the release surface of the release sheet 12a), and heated. It should be hardened. The heating temperature is preferably about 90 to 180° C., and the heating time is preferably about 1 to 5 minutes.

When the first pressure-sensitive adhesive layer 111 is composed of a silicone-based pressure-sensitive adhesive, the lower limit of the thickness of the first pressure-sensitive adhesive layer 111 is preferably 5 μm or more, more preferably 10 μm or more. , particularly preferably 15 μm or more, more preferably 20 μm or more. When the lower limit value of the thickness of the first pressure-sensitive adhesive layer 111 is above, the adhesive strength is further improved. On the other hand, the upper limit of the thickness of the first adhesive layer 111 described above is preferably 100 μm or less, preferably 70 μm or less, particularly preferably 50 μm or less, and further preferably 30 μm or less. is preferred. When the upper limit value of the thickness of the first pressure-sensitive adhesive layer 111 is above, the easy peeling property becomes more excellent. The first pressure-sensitive adhesive layer 111 made of a silicone-based pressure-sensitive adhesive may be formed as a single layer, or may be formed by laminating a plurality of layers.

1-2. Second Adhesive Layer The adhesive constituting the second adhesive layer 112 is an adhesive different from the adhesive constituting the first adhesive layer 111, and has an adhesive force to glass F _g2 and to resin. The film adhesive strength _Fr3 is not particularly limited as long as it falls within the range described above. As the type of the adhesive, for example, any of an acrylic adhesive, a silicone adhesive, a polyester adhesive, a polyurethane adhesive, and a rubber adhesive may be used. The adhesive may be emulsion type, solvent type or non-solvent type, and may be crosslinked or non-crosslinked. Among them, the acrylic pressure-sensitive adhesive or the silicone pressure-sensitive adhesive is preferable because it easily achieves the above-described adhesive strength.

(1) Acrylic Adhesive The acrylic adhesive that constitutes the second adhesive layer 112 may be non-curable with active energy rays, but should be curable with active energy rays. preferable. Since the second adhesive layer 112 is composed of an active energy ray-curable acrylic adhesive, when the work is separated from the adhesive sheet after the completion of the process, the work is exposed to the irradiation of the active energy ray. It becomes possible to reduce the adhesive force to and to separate more easily.

The active energy ray-curable acrylic pressure-sensitive adhesive described above may be composed mainly of a polymer having active energy ray-curable properties (active energy ray-curable polymer), or may have active energy ray-curable properties. The main component may be a mixture of a polymer having no active energy ray-curable group (active energy ray non-curable polymer) and a monomer and/or oligomer having at least one or more active energy ray-curable groups.

Among them, the active energy ray-curable acrylic pressure-sensitive adhesive constituting the second pressure-sensitive adhesive layer 112 in the present embodiment is easy to achieve the above-described adhesive strength (especially the resin film adhesive strength F _r3 ). It is preferably composed mainly of an active energy ray-curable polymer. In particular, the adhesive is a (meth)acrylic acid ester polymer (hereinafter referred to as It may be referred to as "active energy ray-curable polymer") and an adhesive composition (hereinafter sometimes referred to as "adhesive composition P2") containing a crosslinking agent (hereinafter referred to as "adhesive composition P2") (adhesive It is preferably a pressure-sensitive adhesive obtained by cross-linking the adhesive composition P2.

(1-1) Active energy ray-curable polymer The active energy ray-curable polymer is an acrylic copolymer having a functional group-containing monomer unit and an unsaturated group-containing compound having a functional group that binds to the functional group. It is preferably obtained by reacting with.

The above acrylic copolymer preferably contains a structural unit derived from a functional group-containing monomer and a structural unit derived from a (meth)acrylic acid alkyl ester monomer or a derivative thereof. As described above, the functional group possessed by the functional group-containing monomer is used for reaction with the unsaturated group-containing compound and also for reaction with the cross-linking agent. As a result, a crosslinked structure (three-dimensional network structure) is formed in the second adhesive 112 to achieve desired cohesion.

The functional group-containing monomer as a structural unit of the acrylic copolymer for the second adhesive layer 112 includes a polymerizable double bond, a hydroxyl group, a carboxyl group, an amino group, a substituted amino group, an epoxy group, and the like. It is preferably a monomer having a functional group in its molecule. The functional group possessed by the functional group-containing monomer is used in the reaction between the acrylic copolymer and the cross-linking agent, and when the reaction occurs, a cross-linked structure (three-dimensional network structure) is formed in the adhesive, resulting in desired aggregation. power is achieved.

As the hydroxy group-containing monomer, the same hydroxy group-containing monomer as the structural unit of the acrylic copolymer for the first adhesive layer 111 can be used. In the acrylic copolymer for the second pressure-sensitive adhesive layer 112, among the hydroxyl group-containing monomers described above, 4-hydroxybutyl (meth)acrylate is preferred from the viewpoint that the reaction with the cross-linking agent proceeds favorably. , 2-hydroxyethyl (meth)acrylate and 2-hydroxypropyl (meth)acrylate, particularly preferably 4-hydroxybutyl acrylate.

As the carboxy group-containing monomer, amino group-containing monomer, and substituted amino group-containing monomer, the same monomers as those described above as the structural units of the acrylic copolymer for the first pressure-sensitive adhesive layer 111 can be used.

The acrylic copolymer preferably contains 5% by mass or more, more preferably 10% by mass or more, of structural units derived from the functional group-containing monomer as monomer units constituting the polymer. In particular, it is preferably contained in an amount of 20% by mass or more, more preferably 26% by mass or more. In addition, the acrylic copolymer preferably contains 50% by mass or less, particularly 40% by mass or less, of structural units derived from the functional group-containing monomer as monomer units constituting the polymer. Preferably, it is contained in an amount of 35% by mass or less. When the acrylic copolymer contains the monomer units constituting the polymer within the above range, it has a desired cohesive force and facilitates the formation of a pressure-sensitive adhesive exhibiting the above-described adhesive physical properties.

As the (meth)acrylic acid alkyl ester monomer as a structural unit of the acrylic copolymer, a (meth)acrylic acid alkyl ester monomer having an alkyl group having 1 to 20 carbon atoms is preferable. Alkyl groups may be linear or branched, or may have a cyclic structure. As for the (meth)acrylic acid alkyl ester monomer having 1 to 20 carbon atoms in the alkyl group, the same monomer as described above can be used as the structural unit of the acrylic copolymer for the first pressure-sensitive adhesive layer 111. .

In addition, the (meth)acrylic acid alkyl ester monomer having an alkyl group having 1 to 20 carbon atoms preferably contains a low Tg alkyl acrylate. By containing such a low Tg alkyl acrylate as a constituent monomer unit, the pressure-sensitive adhesive obtained easily exhibits suitable viscoelasticity, and not only in a room temperature environment but also when the pressure-sensitive adhesive is exposed to high temperatures. Also, it becomes easy to achieve the desired adhesive strength. As for the low Tg alkyl acrylate, the same monomer as described above can be used as the structural unit of the acrylic copolymer for the first pressure-sensitive adhesive layer 111 . Also in the acrylic copolymer for the second adhesive layer 112, at the same time as the acrylic copolymer for the first adhesive layer 111, as a low Tg alkyl acrylate, the Tg of the homopolymer is −45° C. or less. It is preferable to use one having a temperature of −50° C. or lower. Specifically, n-butyl acrylate and 2-ethylhexyl acrylate are preferably used.

When two or more types of low-Tg alkyl acrylates are used in combination, it is preferable that the content of the low-Tg alkyl acrylate having the lowest Tg among the low-Tg alkyl acrylates to be used is large, from the viewpoint that the workpiece can be easily separated from the substrate after the process is completed. .

The acrylic copolymer preferably contains 35% by mass or more, particularly preferably 45% by mass or more, and further preferably 55% by mass or more of a low-Tg alkyl acrylate as a monomer unit constituting the polymer. It is preferable to contain. In addition, the acrylic copolymer preferably contains 90% by mass or less, particularly preferably 80% by mass or less, and further preferably 70% by mass, of a low-Tg alkyl acrylate as a monomer unit constituting the polymer. % or less.

In addition, the acrylic copolymer for the second pressure-sensitive adhesive layer 112 preferably contains a nitrogen atom-containing monomer as a monomer unit constituting the polymer. Adhesion to an adherend (substrate) such as glass can be improved by containing a nitrogen atom-containing monomer. Examples of nitrogen atom-containing monomers include monomers having an amino group, monomers having an amide group, and monomers having a nitrogen-containing heterocyclic ring. Among them, monomers having a nitrogen-containing heterocyclic ring are preferred. In addition, from the viewpoint of increasing the degree of freedom of the portion derived from the nitrogen atom-containing monomer in the higher-order structure of the pressure-sensitive adhesive, the nitrogen atom-containing monomer is used for polymerization to form an acrylic copolymer. It preferably contains no reactive unsaturated double bond groups other than one polymerizable group.

Examples of monomers having a nitrogen-containing heterocyclic ring include N-(meth)acryloylmorpholine, N-vinyl-2-pyrrolidone, N-(meth)acryloylpyrrolidone, N-(meth)acryloylpiperidine, N-(meth)acryloyl pyrrolidine, N-(meth)acryloylaziridine, aziridinylethyl (meth)acrylate, 2-vinylpyridine, 4-vinylpyridine, 2-vinylpyrazine, 1-vinylimidazole, N-vinylcarbazole, N-vinylphthalimide, etc. Among them, N-(meth)acryloylmorpholine, which exhibits superior adhesive strength, is preferred, and N-acryloylmorpholine is particularly preferred.

Examples of nitrogen atom-containing monomers include (meth)acrylamide, N-methyl(meth)acrylamide, N-methylol(meth)acrylamide, N-tert-butyl(meth)acrylamide, and N,N-dimethyl(meth)acrylamide. , N,N-ethyl (meth)acrylamide, N,N-dimethylaminopropyl (meth)acrylamide, N-isopropyl (meth)acrylamide, N-phenyl (meth)acrylamide, dimethylaminopropyl (meth)acrylamide, N-vinyl Caprolactam, monomethylaminoethyl (meth)acrylate, monoethylaminoethyl (meth)acrylate, monomethylaminopropyl (meth)acrylate, monoethylaminopropyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, etc. can also be used.

One type of the above nitrogen atom-containing monomer may be used alone, or two or more types may be used in combination.

From the viewpoint of improving adhesion to adherends such as glass, the acrylic copolymer for the second pressure-sensitive adhesive layer 112 contains 1% by mass of a nitrogen atom-containing monomer as a monomer unit constituting the polymer. It is preferably contained in an amount of 5% by mass or more, more preferably 5% by mass or more, and particularly preferably 8% by mass or more. In addition, the content of the nitrogen atom-containing monomer is preferably 20% by mass or less, more preferably 16% by mass or less, and 12% by mass or less, from the viewpoint of ensuring the blending amount of other components. is particularly preferred.

The acrylic copolymer for forming the second pressure-sensitive adhesive layer 112 may optionally contain other monomers as monomer units forming the polymer. Examples of such monomers include monomers having an alicyclic structure in the molecule (alicyclic structure-containing monomers), alkoxyalkyl (meth)acrylates such as methoxyethyl (meth)acrylate and ethoxyethyl (meth)acrylate. Examples include esters, vinyl acetate, styrene, and the like. These may be used alone or in combination of two or more.

In addition, in the acrylic pressure-sensitive adhesive for forming the second pressure-sensitive adhesive layer 112, the acrylic copolymer is obtained by a solution polymerization method in the same manner as the acrylic copolymer for the first pressure-sensitive adhesive layer 111. It is preferable that the acrylic copolymer is a solution polymerized product, and the polymerization mode of the acrylic copolymer may be a random copolymer or a block copolymer.

The unsaturated group-containing compound is not particularly limited as long as it has a functional group capable of reacting with the functional group of the functional group-containing monomer unit of the acrylic copolymer. The functional group possessed by the unsaturated group-containing compound can be appropriately selected according to the type of functional group possessed by the acrylic copolymer. For example, when the functional group possessed by the acrylic copolymer is a hydroxy group, an amino group or a substituted amino group, the functional group possessed by the unsaturated group-containing compound is preferably an isocyanate group or an epoxy group, and the acrylic copolymer possesses When the functional group is an epoxy group, the functional group possessed by the unsaturated group-containing compound is preferably an amino group, a carboxyl group or an aziridinyl group.

In addition, the unsaturated group-containing compound preferably contains at least one active energy ray-polymerizable carbon-carbon double bond per molecule, particularly preferably 1 to 6, and further. 1 to 4 are preferably included. Specific examples of such unsaturated group-containing compounds include, for example, 2-methacryloyloxyethyl isocyanate, meta-isopropenyl-α,α-dimethylbenzyl isocyanate, methacryloyl isocyanate, allyl isocyanate, 1,1-(bisacryloyloxy Methyl) ethyl isocyanate; Acryloyl monoisocyanate compound obtained by reaction of diisocyanate compound or polyisocyanate compound and hydroxyethyl (meth) acrylate; Diisocyanate compound or polyisocyanate compound, polyol compound and hydroxyethyl (meth) acrylate Acryloyl monoisocyanate compound obtained by reaction; glycidyl (meth) acrylate; (meth) acrylic acid, 2-(1-aziridinyl) ethyl (meth) acrylate, 2-vinyl-2-oxazoline, 2-isopropenyl-2-oxazoline etc.

The unsaturated group-containing compound is preferably used in a proportion of 50 mol% or more, more preferably 60 mol% or more, relative to the number of moles of functional group-containing monomers in the acrylic copolymer. In particular, it is preferably used at a rate of 70 mol % or more, more preferably at a rate of 80 mol % or more, most preferably at a rate of 88 mol % or more. Further, the unsaturated group-containing compound is preferably used at a ratio of 99 mol% or less, particularly 95 mol% or less, relative to the number of moles of functional group-containing monomers in the acrylic copolymer. is preferred, and it is more preferred to be used in a proportion of 92 mol % or less.

An active energy ray-curable polymer can be obtained by reacting the functional group of the above-described acrylic copolymer with the functional group of the unsaturated group-containing compound.

In the reaction between the acrylic copolymer and the unsaturated group-containing compound, the reaction temperature, pressure, and solvent may vary depending on the combination of the functional groups of the acrylic copolymer and the unsaturated group-containing compound. , time, the presence or absence of a catalyst, and the type of catalyst can be selected as appropriate. As a result, the functional group present in the acrylic copolymer reacts with the functional group in the unsaturated group-containing compound, the unsaturated group is introduced into the side chain in the acrylic copolymer, and the active energy ray A curable polymer is obtained.

The weight average molecular weight (Mw) of the active energy ray-curable polymer thus obtained is preferably 100,000 or more, more preferably 200,000 or more, and particularly preferably 400,000 or more. , and more preferably 600,000 or more. Also, the weight average molecular weight (Mw) is preferably 1,500,000 or less, particularly preferably 1,200,000 or less, and more preferably 900,000 or less. When the weight-average molecular weight (Mw) is within the above range, the obtained adhesive easily satisfies the adhesive physical properties described above.

(1-2) Cross-linking agent In the acrylic pressure-sensitive adhesive for forming the second pressure-sensitive adhesive layer 112, the cross-linking agent may be one that reacts with the functional groups possessed by the active energy ray-curable polymer. Specific examples thereof include those similar to the cross-linking agent used for the acrylic pressure-sensitive adhesive for forming the first pressure-sensitive adhesive layer 111 .

The content of the cross-linking agent in the adhesive composition P2 is preferably 0.01 parts by mass or more, particularly 0.1 parts by mass or more, relative to 100 parts by mass of the active energy ray-curable polymer. is preferred, and more preferably 0.3 parts by mass or more. The content is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, particularly preferably 2 parts by mass or less, and further preferably 0.7 parts by mass or less. is preferred. When the content of the cross-linking agent is within the above range, the cohesive force of the obtained adhesive becomes moderately high, and the adhesive physical properties described above are easily satisfied.

(1-3) Photopolymerization Initiator In the acrylic pressure-sensitive adhesive for forming the second pressure-sensitive adhesive layer 112, when ultraviolet rays are used as active energy rays for curing the pressure-sensitive adhesive, the adhesive composition It is preferred that P2 contains a photoinitiator. Thereby, the polymerization curing time and the amount of light irradiation can be reduced.

Specific examples of photopolymerization initiators include benzophenone, acetophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin benzoic acid, benzoin methyl benzoate, benzoin dimethyl ketal, 2,4 -diethylthioxanthone, 1-hydroxycyclohexylphenyl ketone, benzyldiphenylsulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, benzyl, dibenzyl, diacetyl, β-chloranthraquinone, (2,4,6-trimethyl benzyldiphenyl)phosphine oxide, 2-benzothiazole-N,N-diethyldithiocarbamate, oligo{2-hydroxy-2-methyl-1-[4-(1-propenyl)phenyl]propanone}, 2,2-dimethoxy -1,2-diphenylethan-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one etc. These may be used independently and may use 2 or more types together.

The content of the photopolymerization initiator in the adhesive composition P2 is preferably 0.4 parts by mass or more, particularly 0.8 parts by mass or more, relative to 100 parts by mass of the active energy ray-curable polymer. It is preferably 1.2 parts by mass or more. On the other hand, the content is preferably 10 parts by mass or less, particularly preferably 6 parts by mass or less, and further preferably 4 parts by mass or less. When the content of the photopolymerization initiator is within the above range, it becomes possible to easily satisfy the adhesive physical properties described above, and it is also possible to effectively reduce the polymerization curing time and the amount of light irradiation.

(1-4) Various Additives The adhesive composition P2 may optionally contain various additives commonly used in active energy ray-curable adhesives, such as silane coupling agents, ultraviolet absorbers, curing retarders, Tackifiers, antioxidants, light stabilizers, softeners, fillers and the like can be added. These specific examples are the same as those described above for the first adhesive layer 111 . Also, the amount of addition when using these additives is the same as the amount of addition described above for the first pressure-sensitive adhesive layer 111 .

(1-5) Production of adhesive composition P2 Adhesive composition P2 is produced by producing an active energy ray-curable polymer, the obtained active energy ray-curable polymer, a cross-linking agent, and optionally photopolymerization. It can be produced by mixing an initiator and other additives. Further, if desired, a diluent solvent may be added to the adhesive composition P2 and thoroughly mixed to obtain an adhesive composition P (coating solution) diluted with a solvent.

In any of the above components, if a solid one is used, or if precipitation occurs when mixed with other components in an undiluted state, the component is added alone in advance to a dilution solvent. It may be dissolved or diluted prior to mixing with other ingredients.

Preferred examples of the diluent solvent are the same as the diluent solvent described above for the first adhesive layer 111 . Further, the preferred range of the concentration and viscosity of the coating solution of the adhesive composition P2 is the same as the concentration and viscosity of the adhesive composition P1.

(1-6) Formation of Second Adhesive Layer The second adhesive layer 112 can be formed by crosslinking the applied adhesive composition P2. Crosslinking of the adhesive composition P2 is preferably performed by heat treatment. Note that this heat treatment can also serve as a drying treatment after application of the adhesive composition P2. The heating temperature and heating time of the heat treatment can be the same as those of the heat treatment for the adhesive composition P1. It is also preferable to provide a curing period of about 1 to 2 weeks at room temperature (eg, 23° C., 50% RH) after the heat treatment. By the above heat treatment (and curing), the active energy ray-curable polymer is satisfactorily crosslinked via the crosslinking agent.

(1-7) Thickness of second adhesive layer 112 When the second adhesive layer 112 is composed of an acrylic adhesive, the thickness of the second adhesive layer 111 (JIS K7130: The lower limit of the value measured according to the same method) is preferably 5 μm or more, particularly preferably 10 μm or more, and further preferably 15 μm or more. When the lower limit value of the thickness of the second pressure-sensitive adhesive layer 112 is above, the adhesive strength is further improved. The upper limit of the thickness of the first pressure-sensitive adhesive layer 111 is preferably 50 μm or less, particularly preferably 40 μm or less, further preferably 30 μm or less. When the upper limit value of the thickness of the second pressure-sensitive adhesive layer 112 is above, the easy peeling property becomes more excellent. The second adhesive layer 112 made of an acrylic adhesive may be formed as a single layer, or may be formed by laminating a plurality of layers.

(2) Silicone-based adhesive When the second adhesive layer 112 is made of a silicone-based adhesive, the silicone-based adhesive may be the silicone-based adhesive described above for the first adhesive layer 111. You can use something similar to

That is, the silicone-based pressure-sensitive adhesive for forming the second pressure-sensitive adhesive layer 112 preferably contains organopolysiloxane, particularly addition-type organopolysiloxane (cured product thereof). The addition-type organopolysiloxane is preferably obtained by reacting an organopolysiloxane having a siloxane bond as a main skeleton and an alkenyl group with an organohydrogenpolysiloxane. As I said.

In addition, the silicone-based pressure-sensitive adhesive preferably contains a platinum catalyst, and specific examples thereof and the content in the silicone-based pressure-sensitive adhesive are as described above. Furthermore, an organopolysiloxane (silicone resin) containing trifunctional or tetrafunctional siloxane units in the molecule can also be used, and the content in the silicone pressure-sensitive adhesive is as described above.

If desired, the silicone-based pressure-sensitive adhesive for forming the second pressure-sensitive adhesive layer 112 may contain various additives commonly used in silicone-based pressure-sensitive adhesives, such as silane coupling agents, ultraviolet absorbers, curing retarders, Tackifiers, antioxidants, light stabilizers, softeners, fillers and the like can be added. These specific examples and the amounts of additives to be added are the same as those described above for the first pressure-sensitive adhesive layer 111 .

In order to form the second pressure-sensitive adhesive layer 112 with a silicone-based pressure-sensitive adhesive, in the same manner as in the case of forming the first pressure-sensitive adhesive layer 111, for example, addition type organopolysiloxane and optionally trifunctional or tetrafunctional A coating solution obtained by diluting an organopolysiloxane containing a polysiloxane unit and a platinum catalyst with the solvent described above to about 10 to 60% by mass is applied to an object to be coated (for example, the core material 113 or the release surface of the release sheet 12b). is applied to the surface and heated to cure. The heating temperature and heating time in the heating can be the same as in the case of forming the first adhesive layer 111 .

When the second pressure-sensitive adhesive layer 112 is composed of a silicone-based pressure-sensitive adhesive, the lower limit of the thickness of the second pressure-sensitive adhesive layer 112 is preferably 5 μm or more, more preferably 10 μm or more. , particularly preferably 15 μm or more, more preferably 20 μm or more. When the lower limit value of the thickness of the second pressure-sensitive adhesive layer 112 is above, the adhesive strength is further improved. On the other hand, the upper limit of the thickness of the second adhesive layer 112 described above is preferably 100 μm or less, more preferably 70 μm or less, particularly preferably 50 μm or less, and further preferably 30 μm or less. Preferably. When the upper limit value of the thickness of the second pressure-sensitive adhesive layer 112 is above, the easy peeling property becomes more excellent. The second pressure-sensitive adhesive layer 112 made of a silicone-based pressure-sensitive adhesive may be formed as a single layer, or may be formed by laminating a plurality of layers.

1-3. Core Material The pressure-sensitive adhesive sheet 1 according to the present embodiment has a predetermined rigidity due to the provision of the core material 113, and can easily achieve desired handling properties. However, the adhesive sheet 1 according to this embodiment may not have the core material 113 .

The core material 113 is preferably made of a plastic film. Types of plastic films include, for example, polyester films made of polyester such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyurethane films, polyethylene films, polypropylene films, cellulose films such as triacetyl cellulose, polyvinyl chloride films, poly Plastic films such as vinylidene chloride films, polyvinyl alcohol films, ethylene-vinyl acetate copolymer films, polystyrene films, polycarbonate films, acrylic resin films, norbornene-based resin films, cycloolefin resin films; laminates of two or more of these, etc. can be mentioned. The plastic film may be uniaxially or biaxially oriented. Among these, polyester films are preferred, and polyethylene terephthalate films are particularly preferred.

In the core material 113 made of the plastic film as described above, for the purpose of improving adhesion with the adjacent first adhesive layer 111 and/or the second adhesive layer 112, one side or both sides may be coated if desired. can be subjected to a surface treatment such as an oxidation method or a primer treatment. Examples of the oxidation method include corona discharge treatment, plasma discharge treatment, chromium oxidation treatment (wet type), flame treatment, hot air treatment, ozone, and ultraviolet irradiation treatment. These surface treatment methods are appropriately selected according to the type of plastic film, but generally corona discharge treatment is preferably used from the viewpoint of effectiveness and operability.

The thickness of the core material 113 is preferably 2 μm or more, particularly preferably 5 μm or more, further preferably 10 μm or more, from the viewpoint of improving handling properties of the adhesive sheet 1 . From the same viewpoint, the thickness of the core material 113 is preferably 250 μm or less, more preferably 125 μm or less, particularly preferably 75 μm or less, and further preferably 40 μm or less. .

1-4. Release Sheet The release sheets 12a and 12b protect the first adhesive layer 111 and the second adhesive layer 112 until the adhesive sheet 1 is used, and are peeled off when the adhesive sheet 1 is used. In the adhesive sheet 1 according to this embodiment, one or both of the release sheets 12a and 12b are not necessarily required.

Examples of the release sheets 12a and 12b include polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polyethylene naphthalate film, and polybutylene. Terephthalate film, polyurethane film, ethylene vinyl acetate film, ionomer resin film, ethylene/(meth)acrylic acid copolymer film, ethylene/(meth)acrylic acid ester copolymer film, polystyrene film, polycarbonate film, polyimide film, fluorine A resin film or the like is used. Crosslinked films of these are also used. Furthermore, a laminated film of these may be used.

The release surfaces of the release sheets 12a and 12b (especially the surfaces in contact with the first pressure-sensitive adhesive layer 111 or the second pressure-sensitive adhesive layer 112) are preferably subjected to a release treatment. Examples of release agents used in the release treatment include alkyd-based, silicone-based, fluorine-based, unsaturated polyester-based, polyolefin-based, and wax-based release agents. Of the release sheets 12a and 12b, it is preferable that one of the release sheets is a heavy release type release sheet with a large release force, and the other release sheet is a light release type release sheet with a small release force.

Although the thickness of the release sheets 12a and 12b is not particularly limited, it is usually about 20 to 150 μm.

2. Production of Adhesive Sheet The production method of the adhesive sheet 1 according to the present embodiment is not particularly limited, and conventionally known methods can be used. For example, the coating liquid of the adhesive composition P1 described above is applied to the release surface of the release sheet 12a, and heat treatment is performed to thermally crosslink the adhesive composition P1 to form a coating layer. One surface of the core material 113 is superimposed on the . Further, the coating liquid of the adhesive composition P2 described above is applied to the release surface of the release sheet 12b, and heat treatment is performed to thermally crosslink the adhesive composition P2 to form a coating layer. , is superimposed on the other surface of the core material 113 described above. The laminate thus obtained is given a curing period if necessary, so that the two coating layers described above can be used as the first adhesive layer 111 and the second adhesive layer 112, respectively. . On the other hand, when the curing period is unnecessary, the two coating layers described above can be used as the first adhesive layer 111 and the second adhesive layer 112 as they are. As a result, the adhesive sheet 1 is obtained in which the release sheet 12a, the first adhesive layer 111, the core material 113, the second adhesive layer 112 and the release sheet 12b are laminated in order.

As a method for applying the coating liquid of the adhesive composition P1 and the adhesive composition P2 described above, for example, a bar coating method, a knife coating method, a roll coating method, a blade coating method, a die coating method, a gravure coating method, or the like is used. be able to.

3. Use of Adhesive Sheet As described above, the adhesive sheet 1 according to the present embodiment fixes a device such as an optical member or an electronic member as a work, preferably a flexible device, to a substrate during processes such as processing, lamination, and inspection. It is preferably used for After the above steps are finished, the workpiece is separated from the substrate.

FIG. 2 shows a cross-sectional view of the laminate 4 showing how the pressure-sensitive adhesive sheet 1 is used. The laminate 4 according to the present embodiment includes a flexible device 2 as a work and each layer constituting the adhesive sheet 1 (first adhesive layer 111, core material 113 and second adhesive layer 112 in FIG. 4). , and a substrate 3 are laminated in that order. As described above, in the adhesive sheet 1 according to the present embodiment, the surface on the side of the first adhesive layer 111 (first adhesive surface) is attached to the substrate 3, and the surface on the side of the second adhesive layer 112 ( It is preferable to bond the second adhesive surface) to the work. In the laminated body 4, the flexible device 2 is firmly fixed to the substrate 3 via the adhesive sheet 1, so the process can be performed without any problem.

It is preferable that the above-described process includes a process of heating the work or a process of secondarily heating the work. Examples of such heat treatment include a metal vapor deposition process, a resin curing process such as a sealing resin, and an annealing process. In the adhesive sheet 1 and the laminate 4 according to the present embodiment, the adhesive sheet 1 satisfies the above-described adhesive strength to glass F _g2 and adhesive strength to resin film F _r3 , so that even if heat treatment is performed, after the process The flexible device 2 can be easily separated from the adhesive sheet 1 , and the adhesive sheet 1 after separating the flexible device 2 can be easily peeled from the substrate 3 . Therefore, in the laminate 4 according to the present embodiment, even when the heat treatment is performed, the process can be performed satisfactorily, and the substrate 3 can be satisfactorily reused.

The heat treatment described above may be performed under the same conditions as general heat treatment. For example, the heating temperature is preferably 40° C. or higher, particularly preferably 80° C. or higher, and more preferably 120° C. or higher. The heating temperature is preferably 200° C. or lower, particularly preferably 180° C. or lower, and more preferably 160° C. or lower. The heating time is preferably 5 minutes or longer, particularly preferably 10 minutes or longer, and more preferably 20 minutes or longer. The heating time is preferably 60 minutes or less, particularly preferably 50 minutes or less, and more preferably 40 minutes or less.

When the second pressure-sensitive adhesive layer 112 is composed of an active energy ray-curable pressure-sensitive adhesive, after the above-described steps are completed, the second pressure-sensitive adhesive layer 112 is irradiated with an active energy ray to obtain a second By curing the second adhesive layer 112, the adhesive strength to the work can be reduced. Thereby, the workpiece can be easily peeled off from the second adhesive layer 112 .

As the active energy ray used for exfoliating such a work, ultraviolet rays, electron beams, etc. are usually used, and ultraviolet rays, which are easy to handle, are particularly preferable. When using ultraviolet rays, the irradiation can be performed by a high-pressure mercury lamp, a fusion lamp, a xenon lamp, or the like. As for the irradiation conditions, the illuminance is preferably 50 mW/cm ² or more and 1000 mW/cm ² or less. Further, the integrated light quantity of ultraviolet light is preferably 1500 mJ/cm ² or more, and particularly preferably 2000 mJ/cm ² or more. Further, the cumulative light quantity of ultraviolet rays is preferably 5000 mJ/cm ² or less, and particularly preferably 3000 mJ/cm ² or less.

The embodiments described above are described to facilitate understanding of the present invention, and are not described to limit the present invention. Therefore, each element disclosed in the above embodiments is meant to include all design changes and equivalents that fall within the technical scope of the present invention.

For example, one or both of the release sheets 12a and 12b in the adhesive sheet 1 may be omitted. Also, the core material 113 in the adhesive sheet 1 may be omitted.

EXAMPLES The present invention will be described in more detail with reference to Examples and the like, but the scope of the present invention is not limited to these Examples and the like.

[Preparation Example 1] (Adhesive composition for acrylic adhesive A)
An acrylic copolymer obtained by copolymerizing 50 parts by mass of 2-ethylhexyl acrylate, 10 parts by mass of n-butyl acrylate, 10 parts by mass of acryloylmorpholine, and 30 parts by mass of 4-hydroxybutyl acrylate. and 90 mol % of methacryloyloxyethyl isocyanate (MOI) relative to the number of moles of 4-hydroxybutyl acrylate in the acrylic copolymer to obtain an active energy ray-curable polymer. When the weight average molecular weight (Mw) of this active energy ray-curable polymer was measured by the method described later, it was 700,000.

100 parts by mass of the obtained active energy ray-curable polymer (in terms of solid content, hereinafter the same) and an aliphatic isocyanate having hexamethylene diisocyanate as a cross-linking agent (manufactured by Nippon Polyurethane Industry Co., Ltd., product name "Coronate HX") 0.75 parts by mass, 5.00 parts by mass of a curing retarder (manufactured by Toyochem, product name "BXX5638"), and 2-hydroxy-1-{4-[4-(2-hydroxy -2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one and 0.10 parts by mass in a solvent to obtain a coating liquid of the adhesive composition for acrylic adhesive A. rice field.

[Preparation Example 2] (Adhesive composition for acrylic adhesive B)
Obtained by copolymerizing 47.8 parts by mass of 2-ethylhexyl acrylate, 47.8 parts by mass of n-butyl acrylate, 4 parts by mass of acrylic acid, and 0.4 parts by mass of 2-hydroxypropyl acrylate. An acrylic copolymer was obtained. When the weight average molecular weight (Mw) of this acrylic copolymer was measured by the method described later, it was 800,000.

100 parts by mass of the obtained acrylic copolymer and 7 parts by mass of trimethylolpropane-modified tolylene diisocyanate (manufactured by Toyochem Co., Ltd., product name "BHS8515") as a cross-linking agent are mixed in a solvent to obtain an acrylic pressure-sensitive adhesive. A coating liquid of the adhesive composition for B was obtained.

[Preparation Example 3] (Adhesive composition for acrylic adhesive C)
An acrylic copolymer obtained by copolymerizing 78 parts by mass of 2-ethylhexyl acrylate, 20 parts by mass of n-butyl acrylate, and 2 parts by mass of 2-hydroxyethyl acrylate was obtained. When the weight average molecular weight (Mw) of this acrylic copolymer was measured by the method described later, it was 400,000.

100 parts by mass of the obtained acrylic copolymer, 2 parts by mass of an isocyanate cross-linking agent (manufactured by Saiden Chemical Co., Ltd., product number "K-315") as a cross-linking agent, and a silicone resin (intermediate structure between inorganic and organic (silicon-containing compound having a (named "BXX5638") was mixed in a solvent to obtain a coating liquid of the adhesive composition for acrylic pressure-sensitive adhesive C.

[Preparation Example 4] (Adhesive composition for silicone adhesive)
100 parts by mass of an addition reaction type silicone resin (manufactured by Shin-Etsu Chemical Co., Ltd., product name "KS-847H") as a main agent, and 2 parts by mass of a platinum catalyst (manufactured by Dow Corning Toray Co., Ltd., product name "SRX 212 CATALYST") , 0.6 parts by mass of 8-glycidoxyoctyltrimethoxysilane as a silane coupling agent and 15 parts by mass of a silicone resin (manufactured by Dow Corning Toray Co., Ltd., product name "SD-4584") are mixed, and methyl ethyl ketone is mixed. to obtain a coating liquid of the pressure-sensitive adhesive composition for a silicone-based pressure-sensitive adhesive.

Here, the weight-average molecular weight (Mw) described above is a polystyrene-equivalent weight-average molecular weight measured using gel permeation chromatography (GPC) under the following conditions (GPC measurement).
<Measurement conditions>
・ GPC measurement device: HLC-8320 manufactured by Tosoh Corporation
・ GPC column (passed in the following order): TSK gel superH-H manufactured by Tosoh Corporation
TSK gel super HM-H
TSK gel super H2000
・Measurement solvent: tetrahydrofuran ・Measurement temperature: 40°C

[Example 1]
The coating solution of the adhesive composition for acrylic pressure-sensitive adhesive B prepared in Preparation Example 2 was applied to a light release type release sheet (manufactured by Lintec Corporation, product name "SP- PET382120") was coated with a knife coater on the release-treated surface. The formed coating film was heat-treated at 90° C. for 1 minute to form a pressure-sensitive adhesive layer having a thickness of 20 μm, which was used as a first pressure-sensitive adhesive layer. As a result, a first laminate was obtained in which the light release type release sheet and the first pressure-sensitive adhesive layer were laminated.

In addition, the coating solution of the adhesive composition for acrylic pressure-sensitive adhesive A prepared in Preparation Example 1 was applied to a polyethylene terephthalate film with a heavy release type release sheet (Lintec Co., Ltd., product name " SP-PET751130") was coated with a knife coater. The formed coating film was heat-treated at 90° C. for 1 minute to form a pressure-sensitive adhesive layer having a thickness of 20 μm, which was used as the pressure-sensitive adhesive layer. As a result, a second laminate was obtained in which the second pressure-sensitive adhesive layer and the heavy release type release sheet were laminated.

After that, the first pressure-sensitive adhesive layer side surface of the first laminate is laminated to one surface of a polyethylene terephthalate film (manufactured by Toyobo Co., Ltd., product name “PET A4300”, thickness: 100 μm) as a core material. At the same time, after laminating the second adhesive layer side surface of the second laminate to the other surface, curing for 7 days under the conditions of 23 ° C. and 50% RH, a light release type release sheet / A pressure-sensitive adhesive sheet having a layer structure of first pressure-sensitive adhesive layer/core material/second pressure-sensitive adhesive layer/heavy release type release sheet was obtained.

The thickness of the pressure-sensitive adhesive layer described above is a value measured using a constant pressure thickness measuring instrument (manufactured by Teclock, product name "PG-02") in accordance with JIS K7130.

[Example 2]
A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1, except that a polyethylene terephthalate film (manufactured by Mitsubishi Chemical Corporation, product name: PET38-T100, thickness: 38 μm) was used as the core material.

[Example 3]
A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1, except that the coating liquid of the pressure-sensitive adhesive composition for acrylic pressure-sensitive adhesive C prepared in Preparation Example 3 was used to form the first pressure-sensitive adhesive layer.

[Example 4]
In the same manner as in Example 1, except that the coating solution of the adhesive composition for acrylic pressure-sensitive adhesive C prepared in Preparation Example 3 was used to form the first pressure-sensitive adhesive layer, and the core material was not used. An adhesive sheet was produced. The pressure-sensitive adhesive sheet is produced by directly bonding the first pressure-sensitive adhesive layer side surface of the first laminate and the second pressure-sensitive adhesive layer side surface of the second laminate. becomes.

[Example 5]
On one side of a polyethylene terephthalate film (manufactured by Toyobo Co., Ltd., product name “PET A4300”, thickness: 100 μm) as a core material, the coating liquid of the pressure-sensitive adhesive composition for a silicone pressure-sensitive adhesive prepared in Preparation Example 5 was applied. It was applied with a knife coater. The formed coating film was heat-treated at 130° C. for 2 minutes to form a pressure-sensitive adhesive layer having a thickness of 20 μm, which was used as the first pressure-sensitive adhesive layer. Next, on the surface opposite to the core material in the first pressure-sensitive adhesive layer, a light release type release sheet (manufactured by Lintec Co., Ltd., product name "SP-PET382120 ”) was laminated. As a result, a third laminate was obtained in which the light release type release sheet, the first pressure-sensitive adhesive layer and the core material were laminated in this order.

Subsequently, the surface of the second adhesive layer side of the second laminate prepared in the same manner as in Example 1 was bonded to the core material side surface of the third laminate obtained as described above. After that, by curing for 7 days under conditions of 23 ° C. and 50% RH, the layer configuration of light release release sheet / first adhesive layer / core material / second adhesive layer / heavy release release sheet A pressure-sensitive adhesive sheet having

[Example 6]
On one side of a polyethylene terephthalate film (manufactured by Toyobo Co., Ltd., product name “PET A4300”, thickness: 100 μm) as a core material, the coating liquid of the pressure-sensitive adhesive composition for a silicone pressure-sensitive adhesive prepared in Preparation Example 5 was applied. It was applied with a knife coater. The formed coating film was heat-treated at 130° C. for 2 minutes to form a pressure-sensitive adhesive layer having a thickness of 20 μm, which was used as a second pressure-sensitive adhesive layer. Next, on the surface opposite to the core material in the second pressure-sensitive adhesive layer, a heavy release type release sheet (Lintec Co., Ltd., product name "SP-PET751130 ”) was laminated. As a result, a fourth laminate was obtained in which the core material, the second pressure-sensitive adhesive layer and the heavy release type release sheet were laminated in order.

Subsequently, the first pressure-sensitive adhesive layer side surface of the first laminate prepared in the same manner as in Example 1 was bonded to the core material side surface of the fourth laminate obtained as described above. After that, by curing for 7 days under conditions of 23 ° C. and 50% RH, the layer configuration of light release release sheet / first adhesive layer / core material / second adhesive layer / heavy release release sheet A pressure-sensitive adhesive sheet having

[Comparative Example 1]
The coating liquid of the adhesive composition for acrylic pressure-sensitive adhesive A prepared in Preparation Example 1 was applied to a heavy release type release sheet (manufactured by Lintec Corporation, product name "SP- PET751130") was coated with a knife coater on the release-treated surface. A pressure-sensitive adhesive layer having a thickness of 20 μm was formed by heat-treating the formed coating film at 90° C. for 1 minute.

Then, on the side opposite to the heavy release release sheet in the pressure-sensitive adhesive layer formed as described above, one side of a polyethylene terephthalate film was treated with a silicone-based release agent to release a light release release sheet (manufactured by Lintec). , product name “SP-PET382120”) After laminating the release-treated surface, curing for 7 days under conditions of 23 ° C. and 50% RH, light release release sheet / adhesive layer / heavy release release sheet A pressure-sensitive adhesive sheet having a layer structure of was obtained.

[Comparative Example 2]
A pressure-sensitive adhesive sheet was produced in the same manner as in Comparative Example 1, except that the coating solution of the pressure-sensitive adhesive composition for acrylic pressure-sensitive adhesive C prepared in Preparation Example 3 was used to form the pressure-sensitive adhesive layer.

[Test Example 1] (Measurement of adhesive strength to glass)
The heavy release type release sheet was peeled off from the pressure-sensitive adhesive sheets prepared in Examples and Comparative Examples, and the exposed second pressure-sensitive adhesive layer (single-layer pressure-sensitive adhesive layer in Comparative Examples 1 and 2) was used as a backing material. It was laminated to an easily adhesive layer of a polyethylene terephthalate film (manufactured by Toyobo Co., Ltd., product name "PET A4300", thickness: 25 µm) having an adhesive layer. The laminate thus obtained was cut to a width of 25 mm and a length of 100 mm. The light release type release sheet was peeled off from the laminate after cutting, and the exposed first adhesive layer (single-layer adhesive layer in Comparative Examples 1 and 2) was applied to one side of soda lime glass (manufactured by Nippon Sheet Glass Co., Ltd.). and then allowed to stand under normal pressure, 23° C. and 50% RH conditions for 24 hours to obtain a sample for measuring adhesive force to glass.

For the sample for measuring adhesive force to glass obtained as described above, under the conditions of a peeling speed of 300 mm / min and a peeling angle of 180 degrees in an environment of 23 ° C. and 50% RH, the soda lime glass is subjected to the first adhesion. Laminate having a layer configuration of agent layer / core material / second adhesive layer / backing material (in Example 4, a laminate having a layer configuration of first adhesive layer / second adhesive layer / backing material In Comparative Examples 1 and 2, the laminate having a layer configuration of a single adhesive layer/backing material) was peeled off, and the adhesive strength (N/25 mm) at that time was measured. In addition, the conditions other than those described here were measured according to JIS Z0237:2009. The adhesive strength thus obtained is shown in Table 2 as the adhesive strength to glass F _g1 (N/25 mm) at 23°C.

In addition, a sample for measuring adhesive force to glass obtained in the same manner as above was subjected to heat treatment by placing it in an environment of 100 ° C. and 50% RH for 300 minutes, and then returned to a room temperature environment. The temperature was lowered to room temperature. The adhesive strength of the sample was measured in the same manner as described above, and the adhesive strength F _g2 (N/25 mm) after heat treatment is shown in Table 2.

[Test Example 2] (Measurement of adhesive strength to resin film)
The light-release type release sheet was peeled off from the pressure-sensitive adhesive sheets prepared in Examples and Comparative Examples, and the exposed first pressure-sensitive adhesive layer (single-layer pressure-sensitive adhesive layer in Comparative Examples 1 and 2) was used as a backing material. It was laminated to an easily adhesive layer of a polyethylene terephthalate film (manufactured by Toyobo Co., Ltd., product name "PET A4300", thickness: 25 µm) having an adhesive layer. The laminate thus obtained was cut to a width of 25 mm and a length of 100 mm. The heavy release type release sheet was peeled off from the cut laminate, and the exposed second adhesive layer (single-layer adhesive layer in Comparative Examples 1 and 2) was coated with a polyethylene terephthalate (PET) film as a resin film ( (thickness: 38 μm), and left for 24 hours under the conditions of normal pressure, 23° C. and 50% RH to obtain a sample for measuring adhesion force to resin film.

Regarding the sample for measuring adhesive force to resin film obtained as described above, under the environment of 23 ° C. and 50% RH, under the conditions of a peeling speed of 300 mm / min and a peeling angle of 180 degrees, from the resin film, the backing material / third Laminate having a layer structure of 1 pressure-sensitive adhesive layer / core material / second pressure-sensitive adhesive layer (in Example 4, a laminate having a layer structure of backing material / first pressure-sensitive adhesive layer / second pressure-sensitive adhesive layer In Comparative Examples 1 and 2, the laminate having a layer structure of backing material/single adhesive layer) was peeled off, and the adhesive strength (N/25 mm) at that time was measured. In addition, the conditions other than those described here were measured according to JIS Z0237:2009. The adhesive strength thus obtained is shown in Table 2 as the resin film adhesive strength F _r1 (N/25 mm) at 23°C.

In addition, the pressure-sensitive adhesive sheets of Examples 1 to 5 and Comparative Example 1, which have a second pressure-sensitive adhesive layer formed using the acrylic pressure-sensitive adhesive A having active energy ray-curability, were prepared in the same manner as described above. After irradiating the second pressure-sensitive adhesive layer in the sample for resin film adhesion measurement with ultraviolet rays under the following ultraviolet irradiation conditions through the resin film, under the environment of 23 ° C. and 50% RH, the above Adhesive strength (N/25 mm) was measured in the same manner as. The adhesive strength thus obtained is shown in Table 2 as adhesive strength to resin film F _r2 (N/25 mm) after irradiation with active energy rays.
<Ultraviolet irradiation conditions>
・Using a high-pressure mercury lamp ・Illuminance 200mW/cm ² , cumulative light intensity 2000mJ/cm ² × 1 time

In addition, the adhesive force (N/25 mm) was measured in the same manner as above under the environment of 100° C. and 50% RH for the sample for measuring adhesive force to resin film prepared in the same manner as above. The adhesive strength thus obtained is shown in Table 2 as the resin film adhesive strength F _r3 (N/25 mm) at 100°C.

Further, a sample prepared in the same manner as described above was heat-treated by placing it under high temperature conditions of 300° C. and 50% RH for 300 minutes. After that, the environment was returned to room temperature, and the temperature of the sample was lowered to room temperature. The adhesive strength of the sample was measured in the same manner as described above, and the adhesive strength to the resin film after heat treatment was F _r4 (N/25 mm). Table 2 shows the results.

Furthermore, for the pressure-sensitive adhesive sheets of Examples 1 to 5 and Comparative Example 1, which have a second pressure-sensitive adhesive layer formed using the acrylic pressure-sensitive adhesive A having active energy ray curability, samples prepared in the same manner as described above On the other hand, after performing a heat treatment by placing it under high temperature conditions of 300° C. and 50% RH for 300 minutes, it was returned to the room temperature environment. As a result, the second pressure-sensitive adhesive layer of the sample whose temperature had returned to room temperature was irradiated with ultraviolet rays through the resin film under the above-described ultraviolet irradiation conditions. After that, under the environment of 23° C. and 50% RH, the adhesive strength (N/25 mm) was measured in the same manner as above. The adhesive strength thus obtained is shown in Table 2 as adhesive strength to resin film F _r5 (N/25 mm) after heat treatment and irradiation with active energy rays.

Then, based on the various adhesive strengths measured as described above, the ratio of the adhesive strength to glass F _g2 to the adhesive strength to glass F _g1 (F _g2 /F _g1 ), the adhesive strength to resin film relative to the adhesive strength to glass F _g1 Ratio of F _r1 (F _r1 /F _g1 ), ratio of resin film adhesion F _r4 to resin film adhesion F _r1 (F _r4 /F _r1 ), resin film adhesion to resin film adhesion F _r4 F _r5 ratio (F _r5 /F _r4 ), ratio of resin film adhesive strength F _r2 to glass adhesive strength F _g1 (F _r2 /F _g1 ), resin film adhesive strength F _r4 to glass adhesive strength F _g2 (F _r4 /F _g2 ), and the ratio (F _r5 /F _g2 ) of the resin film adhesive strength F _r5 to the glass adhesive strength F _g2 . These results are also shown in Table 2.

[Test Example 3] (Evaluation of blister resistance)
The light-release type release sheet was peeled off from the pressure-sensitive adhesive sheets obtained in Examples and Comparative Examples, and the exposed surface of the exposed first pressure-sensitive adhesive layer (single-layer pressure-sensitive adhesive layer in Comparative Examples 1 and 2) was covered with soda lime glass. (manufactured by Nippon Sheet Glass Co., Ltd.), peel off the heavy release type release sheet, and remove the exposed surface of the exposed second adhesive layer (single layer adhesive layer in Comparative Examples 1 and 2). It was laminated on one side of an acetylcellulose film (thickness: 60 μm).

The laminated body thus obtained was heat-treated by placing it in an environment of 100° C. and 50% RH for 300 minutes, and then allowed to stand in a room temperature environment to return the temperature of the laminated body to room temperature. After that, it was visually confirmed whether there were air bubbles, floating, or peeling at the interface between the first adhesive layer and the soda lime glass and at the interface between the second adhesive layer and the triacetyl cellulose film. Blister resistance was evaluated according to the standard. Table 3 shows the results.
⊚: No air bubbles, no lifting, and no peeling.
◯: Slight air bubbles, floating or peeling was observed only at the edge of the laminate.
Δ: Bubbles, floating, or peeling occurred at 5 or less locations throughout the laminate.
x: Air bubbles, floating or peeling occurred at 6 or more locations over the entire laminate.

[Test Example 4] (Evaluation of peelability)
The heavy release type release sheet was peeled off from the pressure-sensitive adhesive sheets obtained in Examples and Comparative Examples, and the exposed surface of the exposed second pressure-sensitive adhesive layer (single-layer pressure-sensitive adhesive layer in Comparative Examples 1 and 2) was used as a work. After lamination on one side of a triacetyl cellulose film (thickness: 60 μm), it was cut into a size of 2.5 cm width and 10 cm length (area of the surface where the pressure-sensitive adhesive sheet contacts the work: 25 mm ² ). From the laminate thus obtained, the light release type release sheet was peeled off, and the exposed surface of the exposed first pressure-sensitive adhesive layer (single-layer pressure-sensitive adhesive layer in Comparative Examples 1 and 2) was coated with soda lime as a substrate. A sample for peelability evaluation was obtained by laminating on one side of glass (manufactured by Nippon Sheet Glass Co., Ltd.).

The obtained sample for peelability evaluation was heat-treated by placing it in an environment of 100° C. and 50% RH for 300 minutes, and then allowed to stand in an environment of room temperature to return the temperature of the sample to room temperature. Subsequently, the second pressure-sensitive adhesive layer in the sample was irradiated with ultraviolet rays through the workpiece under the above-described ultraviolet irradiation conditions.

Thereafter, the work was peeled off from the second adhesive layer, and the peelability when the work was peeled off from the adhesive sheet was evaluated based on the following criteria. Table 3 shows the results.
⊚: It was easily peeled off.
◯: Although there was a part that required some force for peeling, or there was a part where adhesive residue was left on the work, it was able to be peeled off.
.DELTA.: Although the work could be peeled off, force was required for peeling in most of the portions, or adhesive residue occurred in most of the portions of the work.
×: Could not be peeled off.

In the above evaluation, for the examples with "◎", "○", and "△", the adhesive sheet was peeled off from the substrate, and the situation at that time was evaluated according to the following criteria when the adhesive sheet was peeled off from the substrate. was evaluated for peelability. Table 3 shows the results.
⊚: It was easily peeled off.
◯: Although there were parts where some force was required for peeling, or there were parts where adhesive remained on the substrate, it was possible to peel.
.DELTA.: Although the substrate could be peeled off, some force was required for peeling in most of the portions, or adhesive residue occurred in most of the portions of the substrate.
×: Could not be peeled off.

Table 1 shows the layer structure of the pressure-sensitive adhesive sheets produced in Examples and Comparative Examples. Details such as abbreviations in Table 1 are as follows.
PET A4300: polyethylene terephthalate film (manufactured by Toyobo Co., Ltd., product name “PET A4300”, thickness: 38 μm)
PET38-T100: polyethylene terephthalate film (manufactured by Mitsubishi Chemical Corporation, product name “PET38-T100”, thickness: 38 μm)

As is clear from Table 3, with the pressure-sensitive adhesive sheets produced in Examples, even when heat treatment is performed, the work can be peeled off from the pressure-sensitive adhesive sheet satisfactorily, and the pressure-sensitive adhesive sheet can be satisfactorily removed from the substrate. We were able to. Therefore, according to the pressure-sensitive adhesive sheet according to the example, it was found that the substrate can be reused satisfactorily.

The pressure-sensitive adhesive sheet according to the present invention is suitable as a pressure-sensitive adhesive sheet for processes used in processes such as processing, lamination and inspection of flexible devices, and is particularly suitable as a pressure-sensitive adhesive sheet for processes used in processes including heat treatment. .

DESCRIPTION OF SYMBOLS 1... Adhesive sheet 111... 1st adhesive layer 112... 2nd adhesive layer 113... Core material 12a, 12b... Release sheet 2... Work (flexible device)
3... Substrate 4... Laminate

Claims (11)

a first adhesive layer;
A pressure-sensitive adhesive sheet comprising a second pressure-sensitive adhesive layer laminated on one side of the first pressure-sensitive adhesive layer and composed of a pressure-sensitive adhesive different from the pressure-sensitive adhesive constituting the first pressure-sensitive adhesive layer, ,
The pressure-sensitive adhesive sheet has a first pressure-sensitive adhesive surface as a surface opposite to the second pressure-sensitive adhesive layer in the first pressure-sensitive adhesive layer, and the first pressure-sensitive adhesive in the second pressure-sensitive adhesive layer Having a second adhesive surface as the surface opposite to the layer,
After heating the first laminate obtained by bonding the first adhesive surface of the adhesive sheet to one side of a glass plate at 100 ° C. for 300 minutes, the temperature of the first laminate is lowered to 23 ° C. The adhesive force F _g2 of the pressure-sensitive adhesive sheet to the glass plate at 23 ° C. to glass is 0.1 N / 25 mm or more and 7 N / 25 mm or less,
Regarding the second laminate obtained by laminating the second adhesive surface of the adhesive sheet to one side of the resin film, the adhesive force F _r3 of the adhesive sheet to the resin film at 100° C. to the resin film is 0.5. A pressure-sensitive adhesive sheet characterized by being 01 N/25 mm or more and 5 N/25 mm or less. After heating the second laminate at 100 ° C. for 300 minutes, the pressure-sensitive adhesive sheet to the resin film at 23 ° C. after lowering the temperature of the second laminate to 23 ° C. 2. The pressure-sensitive adhesive sheet according to claim 1, wherein _Fr4 is 0.01 N/25 mm or more and 10 N/25 mm or less. 3. The pressure-sensitive adhesive sheet according to claim 1, wherein the second pressure-sensitive adhesive layer is composed of an active energy ray-curable pressure-sensitive adhesive. Regarding the first laminate, the adhesive force of the adhesive sheet to the glass plate at 23 ° C. is set to F _g1 ,
When the adhesive force of the adhesive sheet to the resin film at 23 ° C. to the resin film after irradiating the second adhesive layer constituting the second laminate with an active energy ray is _Fr2 to the
The pressure-sensitive adhesive sheet according to claim 3, wherein the ratio (F _r2 /F _g1 ) of the adhesive force F _r2 to the adhesive force F _g1 is 0.001 or more and 10 or less. After heating the second laminate at 100 ° C. for 300 minutes, the temperature of the second laminate is lowered to 23 ° C., and the second adhesive layer constituting the second laminate is When the adhesive force of the adhesive sheet to the resin film at 23 ° C. after being irradiated with an active energy ray is _Fr5 ,
The pressure-sensitive adhesive sheet according to claim 3 or 4, wherein a ratio ( _Fr5 / _Fg2 ) of the adhesive force _Fr5 to the adhesive force _Fg2 is 0.001 or more and 12 or less. The pressure-sensitive adhesive sheet according to any one of claims 1 to 5, further comprising a core material laminated between the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer. During the process, the first adhesive surface is attached to the substrate and the second adhesive surface is attached to the workpiece, thereby fixing the workpiece to the substrate. 7. The pressure-sensitive adhesive sheet according to any one of claims 1 to 6, which is used for peeling from a pressure-sensitive adhesive surface. The pressure-sensitive adhesive sheet according to any one of claims 1 to 7, wherein the application includes heating the workpiece fixed to the substrate. The pressure-sensitive adhesive sheet according to claim 7 or 8, wherein the work is a flexible device. The adhesive sheet comprises two release sheets,
the release surface of one of the release sheets is in contact with the first adhesive surface,
The pressure-sensitive adhesive sheet according to any one of claims 1 to 9, wherein the release surface of the other release sheet is in contact with the second pressure-sensitive adhesive surface. a flexible device;
The pressure-sensitive adhesive sheet according to any one of claims 1 to 10,
The substrate is laminated in that order,
A laminate in which the second adhesive surface of the adhesive sheet is attached to the flexible device, and the first adhesive surface of the adhesive sheet is attached to the substrate.

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