TW202309562A - Optical film with release film - Google Patents

Abstract

An optical film (X) with a release film according to the present invention is provided with an optical film (Y) with an adhesive layer, a light release film (40), and a heavy release film (50). The optical film (Y) with the adhesive layer is provided with an optical film (10) having a first surface (11) and a second surface (12) and having a thickness of 100 [mu]m or less, an adhesive layer (20) affixed to the first surface (11) and having an adhesive surface (21), and an adhesive layer (30) affixed to the second surface (12) and having an adhesive surface (31). The light release film (40) is arranged on the adhesive surface (21), and the heavy release film (50) is arranged on the adhesive surface (31). In a lateral surface irregularity end (E) of the optical film (X), end edges (22, 32) of the adhesive layers (20, 30) are withdrawn further than end edges of the films (10, 40, 50) in an in-plane direction (D), wherein a first withdrawn length d1 of the end edge (22) is smaller than a second withdrawn length d2 of the end edge (32).

Description

Optical film with release film

The invention relates to an optical film with a release film.

The display panel has, for example, a laminated structure including a pixel panel, a touch panel, and a transparent cover film. Optical films with specific optical functions are provided in the laminated structure of the display panel. The optical film may, for example, be a film-shaped polarizing plate or retardation film. The optical film is, for example, manufactured as an optical film with a release film in which an adhesive layer and a release film are respectively provided on both surfaces of the optical film. An optical film with a release film is described in, for example, Patent Document 1 below. [Prior Art Literature] [Patent Document]

[Patent Document 1] Japanese Patent Laid-Open No. 2020-190754

[Problem to be solved by the invention]

Fig. 6 is a schematic cross-sectional view of a film Z as an example of a conventional optical film with a release film. The film Z includes a peeling film 91 , an adhesive layer 92 , an optical film 93 , an adhesive layer 94 , and a peeling film 95 in the thickness direction T in this order. The adhesive layer 92 is attached to one surface of the optical film 93 . The adhesive layer 94 is pasted on the other side of the optical film 93 . The release film 91 is releasably attached to the adhesive layer 92 . The release film 95 is releasably attached to the adhesive layer 94 . In the end E' of the film Z, the edge 91e of the peeling film 91, the edge 92e of the adhesive layer 92, the edge 93e of the optical film 93, the edge 94e of the adhesive layer 94, and the end of the peeling film 95 Edges 95e are on the same plane as each other.

When using such a film Z in the manufacturing process of a display panel, first, the peeling film 91 is peeled from the adhesive layer 92 (1st peeling process). In this step, first, in the edge part E' of the film Z, the force for winding up the peeling film 91 from the adhesive layer 92 is applied to the peeling film 91 as a load for peeling start. This load includes the force required to fully deform the release film 91 at the end E′ and the force required to pull the release film 91 away from the adhesive layer 92 elastically deformed following the deformation of the release film 91 . In the edge part E', when such a load is given, the edge part of the peeling film 91 deform|transforms so that it may be pulled away from the edge 92e of the adhesive agent layer 92. As shown in FIG. Next, the end of the release film 91 is stretched in a direction away from the edge 92 e so as to separate the release film 91 from the adhesive layer 92 , thereby detaching the release film 91 from the adhesive layer 92 . Thereafter, the optical film 93 is bonded to a first adherend (not shown) such as a pixel panel through the exposed adhesive layer 92 . Next, the peeling film 95 is peeled from the adhesive layer 94 (2nd peeling process). Next, the optical film 93 is bonded to a second adherend (not shown) via the adhesive layer 94 exposed by the peeling.

On the other hand, the development of display panels that can be repeatedly bent (foldable), such as for smartphones and tablet terminals, is advancing. In a foldable display panel, each element in the laminated structure is required to be thin and flexible.

However, in the conventional film Z, the thinner the optical film 93 is, the easier it is for the load for starting the peeling in the first peeling step to cause significant deformation of the optical film 93 at the end E′ of the film Z. Such deformation of the optical film 93 causes deformation of the adhesive layer 94 attached to the optical film 93 , and the edge 94 e of the adhesive layer 94 is pulled away from the release film 95 . When the edge 94e separates from the release film 95, the adhesive layer 94 and the release film 95 are easily separated. If separation occurs between the adhesive layer 94 and the release film 95 in the first peeling step, the next step cannot be implemented.

The present invention provides an optical film with a peeling film, which is suitable for peeling off a light peeling film from a thin optical film with adhesive layers on both sides, while suppressing the peeling of a heavy peeling film. [Technical means to solve the problem]

The present invention [1] includes an optical film with a peeling film, which includes an optical film with an adhesive layer, a light peeling film, and a heavy peeling film. The above-mentioned optical film with an adhesive layer includes: an optical film that has A first surface and a second surface opposite to the first surface; a first adhesive layer that is bonded to the first surface and has a first adhesive surface on the opposite side of the optical film; and a second adhesive A layer, which is attached to the second surface and has a second adhesive surface on the opposite side of the optical film; the light release film is arranged on the first adhesive surface, and the heavy release film is arranged on the second adhesive surface, The above-mentioned optical film has a thickness of 100 μm or less, and the above-mentioned optical film with release film has side concave-convex end portions, and in the side concave-convex end portions, in the in-plane direction of the above-mentioned optical film perpendicular to the direction of the above-mentioned thickness, The first edge of the first adhesive layer and the second edge of the second adhesive layer are retreated from the edges of the optical film, the light release film, and the heavy release film, and are located at the concave and convex ends of the side surface. In the section, a first relief length between the first edge and the edge of the light release film is smaller than a second relief length between the second edge and the edge of the heavy release film.

As mentioned above, in the side concavo-convex end portion of the optical film with release film of the present invention, in the in-plane direction of the optical film, the first edge of the first adhesive layer is smaller than the optical film, light release film, And the edges of the heavy peeling film are retreated. In such side concavo-convex end portions, the light release film has a free portion where the first adhesive layer is not bonded. Therefore, when peeling the easy-release film from the first adhesive layer at the concave-convex end of the side surface, first, the free part of the light-release film can be rolled up to deform it, and then the end of the rolled-up and deformed light-release film can be stretched. And the light release film is pulled away from the first edge of the first adhesive layer. That is, in the peeling start process, there is no need to simultaneously apply a force (first force) for sufficiently deforming the end of the light release film and a first adhesive for elastically deforming itself following the deformation of the light release film The force (second force) that the first edge of the layer pulls the light peeling film away (in contrast, in the above-mentioned film Z, the first force and the second force must be applied at the same time, so the force required to start the peeling process larger). Such an optical film with release film is suitable for reducing the force required for the peel initiation process. The smaller the force, the more it can suppress the deformation of the optical film with a thickness of less than 100 μm during the peeling process of the light release film, thereby also suppressing the deformation of the second adhesive layer. Therefore, the second adhesive layer can be suppressed. The second end edge is separated from the gravity peeling film.

Also, as mentioned above, in the concave-convex end portion of the side surface of the optical film with a release film, the first relief length (the edge of the light release film in the film surface direction to the first edge of the first adhesive layer) distance) is smaller than the second back-off length (the distance from the edge of the heavy release film to the second edge of the second adhesive layer in the in-plane direction of the film). That is, the second edge of the second adhesive layer is receded from the first edge of the first adhesive layer in the in-plane direction of the film in the concave-convex end portion of the side surface. Such a configuration is suitable for the above-mentioned second force for pulling the light release film away from the first edge of the first adhesive layer to act on the optical film with the release film in the process of starting the release of the light release film. Therefore, it is suitable to suppress the separation of the second end edge of the second adhesive layer from the weight release film.

The present invention [2] includes the optical film with a release film according to the above [1], wherein the distance between the first edge and the second edge in the in-plane direction is 1 μm or more.

This structure can be preferably used to suppress the above-mentioned deformation of the second adhesive layer during the peeling start of the light release film, and therefore, can be preferably used to suppress the second edge of the second adhesive layer from peeling the film by its own weight. separate.

The present invention [3] includes the optical film with a release film according to the above [1] or [2], wherein the first relief length is 20 μm or more.

This structure is suitable for fully rolling up the end portion (the above-mentioned free portion) of the easy-release film before pulling the easy-release film away from the first edge of the first adhesive layer during the start of peeling of the easy-release film. It deforms it, and therefore, it can preferably be used to reduce the force (total force) required for the start of peeling of the light release film.

The present invention [4] includes the optical film with a release film according to any one of the above-mentioned [1] to [3], wherein the ratio of the above-mentioned first relief length to the thickness of the above-mentioned first adhesive layer is 0.4 or more8 the following.

This structure is suitable for fully rolling up the end portion (the above-mentioned free portion) of the easy-release film before pulling the easy-release film away from the first edge of the first adhesive layer during the start of peeling of the easy-release film. It deforms it, therefore, it can preferably be used to reduce the force required for the peeling initiation of the light release film.

The present invention [5] includes the optical film with a release film according to any one of the above-mentioned [1] to [4], wherein the first peeling initiation force for starting to peel the light release film from the first adhesive surface is relatively low The second peeling initiation force for starting the peeling of the heavy release film from the second adhesive surface is small.

This structure can be preferably used to suppress the above-mentioned deformation of the second adhesive layer during the peeling start of the light release film, and therefore, can be preferably used to suppress the second edge of the second adhesive layer from peeling the film by its own weight. separate.

The present invention [6] includes the optical film with a peeling film according to the above [5], wherein the ratio of the first peeling initiation force to the second peeling initiation force is 0.8 or less.

This structure can be preferably used to suppress the above-mentioned deformation of the second adhesive layer during the peeling start of the light release film, and therefore, can be preferably used to suppress the second edge of the second adhesive layer from peeling the film by its own weight. separate.

The present invention [7] includes the optical film with a peeling film according to the above [6], wherein the first peeling initiation force is less than 800 gf/25 mm.

Such a configuration can be preferably used to suppress separation of the second edge of the second adhesive layer from the heavy release film during the start of peeling of the light release film, and to reduce the load on the optical film.

The present invention [8] includes the optical film with a peeling film according to the above [6] or [7], wherein the second peeling initiation force is 800 gf/25 mm or less.

Such a configuration can be preferably used to suppress separation of the second edge of the second adhesive layer from the heavy release film during the start of peeling of the light release film, and to prevent the separation of the heavy release film from the second adhesive layer. Reduce the load on the optical film.

As shown in FIG. 1 , an optical film X that is an embodiment of an optical film with a release film of the present invention has a light release film 40 (light release liner), an optical film with an adhesive layer, and an optical film X in the thickness direction T sequentially. Film Y, and heavy release film 50 (heavy release liner). The optical film X extends in the in-plane direction D perpendicular to the thickness direction T. The optical film Y with an adhesive layer is an element arranged at the light passage part in the foldable device. The foldable device may, for example, be a foldable display panel. The foldable display panel has, for example, a laminated structure including a pixel panel, a touch panel, and a cover film. There are situations where an optical film with specific optical functions is provided in the laminated structure of the foldable display panel. The optical film may, for example, be a film-shaped polarizing plate or retardation film. The optical film Y with an adhesive layer is used as a supply material for the optical film included in the above-mentioned laminated structure during the manufacturing process of the foldable display panel.

The optical film Y with an adhesive layer includes an optical film 10 having a thickness of 100 μm or less, an adhesive layer 20 (first adhesive layer), and an adhesive layer 30 (second adhesive layer). The optical film 10 has a first surface 11 and a second surface 12 opposite to the first surface 11 . The adhesive layer 20 is attached to the first surface 11 and has an adhesive surface 21 (first adhesive surface) on the opposite side of the optical film 10 . The light release film 40 is disposed on the adhesive surface 21 . The adhesive layer 30 is attached to the second surface 12 and has an adhesive surface 31 (second adhesive surface) on the opposite side of the optical film 10 . The heavy release film 50 is disposed on the adhesive surface 31 . Also, with regard to the edges defining the outer contour shape in plan view, the optical film 10 has an edge 13, the adhesive layer 20 has an edge 22 (first edge), and the adhesive layer 30 has an edge 32 (second edge), The light release film 40 has an end edge 42 and the heavy release film 50 has an end edge 52 .

As shown in FIG. 2 , the optical film X has a side concave-convex end portion E on all or a part of the outer peripheral end of the film. In the side concave-convex end E, in the in-plane direction D, the edges 22, 32 of the adhesive layers 20, 30 are smaller than the edges 13, 42, 52 of the optical film 10, the light release film 40, and the heavy release film 50. retreat. Also, in the concave-convex end portion E of the side surface, the distance d1 between the end edge 22 of the adhesive layer 20 and the end edge 42 of the light release film 40 is greater than the distance between the end edge 32 of the adhesive layer 30 and the end edge of the heavy release film 50. The second retreat length d2 of 52 is small. The first relief length d1 is the distance between the edges 22 and 42 in the in-plane direction D. The second retraction length d2 is the distance between the edges 32 and 52 in the in-plane direction D. The adjustment method of the 1st back-off length d1 is mentioned, for example, the adjustment of the thickness of the adhesive layer 20, and the adjustment of elastic modulus. The adjustment method of the 2nd back-off length d2 is mentioned, for example, the adjustment of the thickness of the adhesive layer 30, and the adjustment of elastic modulus. Also, the method of adjusting the distance between the edges 22 and 32 in the in-plane direction D (i.e., the difference between the first relief length d1 and the second relief length d2) can be, for example, using a rotating Adjustment of the cutting conditions in the cutting step described after the knife is implemented. The cutting conditions include, for example, the taper angle of the blade tip of the rotary blade, the rotational speed of the rotary blade, the incident direction of the rotary blade relative to the surface of the optical film laminate described later, and the displacement speed of the rotary blade for cutting the optical film laminate.

As mentioned above, in the side concave-convex end portion E of the optical film X, in the in-plane direction D, the edge 22 of the adhesive layer 20 is smaller than the edge 13 of the optical film 10, the light release film 40, and the heavy release film 50. , 42, 52 retreat. In such side concave-convex end portion E, the light release film 40 has a free portion 40a where the adhesive layer 20 is not bonded. Therefore, when the light release film 40 is peeled off from the adhesive layer 20 in the side uneven end part E, first, the free part 40a of the light release film 40 can be rolled up as shown by the imaginary line in FIG. 2 to deform it, and then The free portion 40 a that has been rolled up and deformed is stretched to pull the light release film 40 away from the end edge 22 of the adhesive layer 20 . That is, in the process of starting the peeling, it is not necessary to simultaneously apply a force (first force) for sufficiently deforming the free portion 40a of the light release film 40 and an adhesive force for elastically deforming the light release film 40 following the deformation. The edge 22 of the agent layer 20 pulls the light release film 40 away (the second force). Such an optical film X is suitable for reducing the force required for the peel initiation process. The smaller the force, the more it is possible to suppress the deformation of the optical film 10 whose thickness is as thin as 100 μm or less in the process of starting the peeling of the light release film 40, thereby also suppressing the deformation of the adhesive layer 30. Therefore, the adhesive layer 30 can be suppressed. The end edge 32 is separated from the weight release film 50 .

Moreover, as mentioned above, in the side surface concave-convex end part E of the optical film X, the 1st relief length d1 is smaller than the 2nd relief length d2. That is, the edge 32 of the adhesive layer 30 is receded from the edge 22 of the adhesive layer 20 in the in-plane direction D in the concave-convex end portion E of the side surface. This configuration is suitable for suppressing the adhesive when the above-mentioned second force for pulling the easy-release film 40 away from the edge 22 of the adhesive layer 20 acts on the optical film X in the process of starting the peeling of the easy-release film 40 . Deformation of layer 30 is, therefore, adapted to inhibit separation of edge 32 of adhesive layer 30 from weight release film 50 .

As described above, the optical film X is suitable for peeling the light release film 40 from the thin optical film 10 with the adhesive layers 20 , 30 while suppressing the peeling of the heavy release film 50 .

In the optical film X, the distance between the edges 22 and 32 in the in-plane direction D is preferably at least 1 μm, more preferably at least 5 μm, and still more preferably at least 10 μm. Such a configuration can be preferably used to suppress the above-mentioned deformation of the adhesive layer 20 during the above-mentioned peeling initiation process of the light release film 40, and therefore, can be preferably used to suppress the peeling of the film 50 from the edge 42 of the adhesive layer 40 by its own weight. separate. Also, the distance between the edges 22 and 32 in the in-plane direction D is preferably 300 μm or less, more preferably 250 μm or less, further preferably 220 μm or less. This kind of structure can be preferably used to suppress the damage of the end portion of the optical film 10, and can be preferably used to suppress the optical damage caused by the reduction of the bonding area between the optical film 10 and the adhesive layer 20,30. The durability of the end portion of the film 10 is reduced.

The first back-off length d1 is preferably at least 20 μm, more preferably at least 40 μm, and still more preferably at least 60 μm. This structure is suitable for fully rolling up the free part 40a of the easy-release film 40 before pulling the easy-release film 40 away from the edge 22 of the adhesive layer 20 during the above-mentioned peeling start process of the light-release film 40. Its deformation, therefore, can preferably be used to reduce the force (total force) required for the peeling initiation of the light release film 40 . Also, the first back-off length d1 is preferably 500 μm or less, more preferably 400 μm or less, and still more preferably 300 μm or less. As long as the second back-off length d2 is larger than the first back-off length d1, it is preferably at least 21 μm, more preferably at least 41 μm, and still more preferably at least 61 μm. As long as the second back-off length d2 is larger than the first back-off length d1, it is preferably 550 μm or less, more preferably 450 μm or less, and still more preferably 350 μm or less. The ratio (d2/d1) of the second relief length d2 to the first relief length d1 is preferably 1.1 or more, more preferably 1.2 or more. The ratio (d2/d1) is preferably 5 or less, more preferably 4 or less.

The first peeling start force F1 for starting to peel off the light release film 40 from the adhesive surface 21 of the adhesive layer 20 is preferably higher than the second peeling start for starting to peel the heavy release film 50 from the adhesive surface 31 of the adhesive layer 30. The force F2 is small. The ratio (F1/F2) of the first peeling initiation force F1 to the second peeling initiation force F2 is preferably 0.8 or less, more preferably 0.78 or less. The ratio (F1/F2) is preferably at least 0.1, more preferably at least 0.15. These configurations can be preferably used to suppress the above-mentioned deformation of the adhesive layer 20 during the start of peeling of the light release film 40, and therefore, can be preferably used to suppress separation of the edge 32 of the adhesive layer 30 from the weight release film 50. .

In this embodiment, the peeling start force refers to the force required for the peeling start process when the release film releasably adhered to the adhesive layer is peeled from the adhesive layer. During the initiation of peeling, a force acts on the release film in such a way that the release film deforms in a direction away from the adhesive layer. Thereby, the edge of the adhesive layer bonded to the release film and its vicinity are temporarily elastically deformed following the deformation of the release film. Then, when the release film is stretched with a force sufficient to pull the release film away from the end of the adhesive layer elastically deformed in this way, the edge of the adhesive layer and its vicinity and the release film are cracked to start peeling. That is, the peeling start force refers to the force required to start peeling the release film from the adhesive layer by pulling the release film away from the end of the adhesive layer that has elastically deformed during the peeling start process. Such a peeling initiation force can be measured by the method described in the later-mentioned Examples. Such a method of adjusting the peeling initiation force may, for example, be the adjustment of the thickness of the release film and the selection of the type of release treatment agent on the adhesive layer side surface of the release film.

The first peeling start force F1 is preferably less than 800 gf/25 mm, more preferably at most 500 gf/25 mm, further preferably at most 400 gf/25 mm. Such a configuration can be preferably used to suppress separation of the edge 32 of the adhesive layer 30 from the heavy release film 50 during the start of peeling of the light release film 40 and to reduce the load on the optical film 10 . Also, the first peeling initiation force F1 is preferably at least 5 gf/25 mm, more preferably at least 10 gf/25 mm, and still more preferably at least 20 gf/25 mm. Such a configuration can be preferably used to suppress lifting (partial peeling) of the light release film 40 from the adhesive layer 20 during, for example, conveyance and handling of the optical film X.

The peeling force f1 for peeling the light release film 40 from the adhesive surface 21 of the adhesive layer 20 after the start of peeling the light release film 40 from the adhesive layer 20 is preferably 0.1 gf/25 mm or more, more preferably 0.3 gf/25 mm or more. gf/25 mm or more, and more preferably 0.5 gf/25 mm or more. The peel force f1 is preferably at most 5 gf/25 mm, more preferably at most 4 gf/25 mm, further preferably at most 3 gf/25 mm.

The second peeling start force F2 is preferably at most 800 gf/25 mm, more preferably at most 700 gf/25 mm, further preferably at most 600 gf/25 mm. Such a configuration can be preferably used to suppress the separation of the edge 32 of the adhesive layer 30 from the heavy release film 50 during the start of peeling of the light release film 40, and to prevent the peeling of the heavy release film 50 from the adhesive layer 30. The load on the optical film 10 is reduced. Also, the second peeling start force F2 is preferably at least 10 gf/25 mm, more preferably at least 20 gf/25 mm, and still more preferably at least 30 gf/25 mm. Such a configuration can be preferably used to suppress warpage (partial peeling) of the heavy release film 50 from the adhesive layer 30 during conveyance and handling of the optical film X, for example.

The peel force f2 for peeling the heavy release film 50 from the adhesive surface 31 of the adhesive layer 30 after the peeling of the heavy release film 50 from the adhesive layer 30 is preferably 0.1 gf/25 mm or more, more preferably 0.3 gf/25 mm or more. gf/25 mm or more, and more preferably 0.5 gf/25 mm or more. The peel force f2 is preferably at most 5 gf/25 mm, more preferably at most 4 gf/25 mm, further preferably at most 3 gf/25 mm. Moreover, the ratio (f1/f2) of the peeling force f1 to the peeling force f2 is preferably 0.8 or less, more preferably 0.7 or less. The ratio (f1/f2) is preferably at least 0.1, more preferably at least 0.2.

When the optical film 10 is a film-shaped polarizing plate (polarizing film), the polarizing film includes, for example, a polarizing element and a transparent protective film attached to one or both sides of the polarizing element. The polarizing element may, for example, be a uniaxially stretched hydrophilic polymer film on which a dichroic substance is adsorbed, or a polyene alignment film. The hydrophilic polymer film may, for example, be a polyvinyl alcohol film, a partially formalized polyvinyl alcohol film, or an ethylene-vinyl acetate copolymer partially saponified film. As a dichroic substance, iodine and a dichroic dye are mentioned, for example. The polyene alignment film may, for example, be a dehydrated product of polyvinyl alcohol or a dehydrochlorinated product of polyvinyl chloride.

Thin polarizers with a thickness of 10 μm or less can also be used as polarizers. Thin polarizers, for example, include polarizers described in Japanese Patent Laid-Open No. 51-069644, Japanese Patent Laid-Open No. 2000-338329, WO2010/100917, Japanese Patent No. 4691205, and Japanese Patent No. 4751481 .

The transparent protective film is preferably a film excellent in transparency, mechanical strength, heat stability, moisture barrier property, and optical isotropy. The material of such a transparent protective film may, for example, be cellulose resin, cyclic polyolefin resin, acrylic resin, phenylmaleimide resin, or polycarbonate resin.

From the viewpoint of flexibility, the thickness of the polarizing plate is preferably at most 100 μm, more preferably at most 80 μm, and still more preferably at most 70 μm.

The adhesive layer 20 is a pressure-sensitive adhesive layer formed from the first adhesive composition. The adhesive layer 20 has transparency (visible light transmittance). The first adhesive composition contains at least a base polymer.

The base polymer is an adhesive component that expresses adhesiveness in the adhesive layer 20 . Examples of base polymers include acrylic polymers, silicone polymers, polyester polymers, polyurethane polymers, polyamide polymers, polyvinyl ether polymers, vinyl acetate/vinyl chloride copolymers, modified poly Olefin polymers, epoxy polymers, fluoropolymers, and rubber polymers. The base polymer may be used alone or in combination of two or more. From the viewpoint of securing good transparency and adhesiveness of the adhesive layer 20, it is preferable to use an acrylic polymer as the base polymer.

The acrylic polymer is a copolymer containing a monomer component of alkyl (meth)acrylate in a ratio of 50% by mass or more. "(Meth)acrylic acid" means acrylic acid and/or methacrylic acid.

As the alkyl (meth)acrylate, an alkyl (meth)acrylate having 1 to 20 carbon atoms in the alkyl group is preferably used. Alkyl (meth)acrylate may have linear or branched alkyl groups, and may have cyclic alkyl groups such as alicyclic alkyl groups.

Examples of the alkyl (meth)acrylate having a linear or branched alkyl group include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, (meth)acrylate, ) isobutyl acrylate, second butyl (meth)acrylate, third butyl (meth)acrylate, pentyl (meth)acrylate, isopentyl (meth)acrylate, neopentyl (meth)acrylate ester, hexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, (meth)acrylate ) nonyl acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate (meth)acrylic acid isotridecyl ester, (meth)acrylic acid isotetradecyl ester, (meth)acrylate isotetradecyl ester, (meth)acrylate Pentadecyl, Cetyl (meth)acrylate, Heptadecyl (meth)acrylate, Octadecyl (meth)acrylate, Isostearyl (meth)acrylate, and nonadecyl (meth)acrylate.

Examples of alkyl (meth)acrylates having an alicyclic alkyl group include cycloalkyl (meth)acrylates, (meth)acrylates having a bicyclic aliphatic hydrocarbon ring, and (meth)acrylates having three or more rings. (meth)acrylates of aliphatic hydrocarbon rings. As cycloalkyl (meth)acrylate, cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, cycloheptyl (meth)acrylate, and cyclooctyl (meth)acrylate are mentioned, for example. As the (meth)acrylate having a bicyclic aliphatic hydrocarbon ring, for example, iso(meth)acrylate is mentioned. Examples of (meth)acrylates having an aliphatic hydrocarbon ring having three or more rings include dicyclopentyl (meth)acrylate, dicyclopentyloxyethyl (meth)acrylate, and tricyclopentyl (meth)acrylate. , 1-adamantyl (meth)acrylate, 2-methyl-2-adamantyl (meth)acrylate, and 2-ethyl-2-adamantyl (meth)acrylate.

Alkyl (meth)acrylate is preferably an alkyl acrylate having an alkyl group with 3 to 15 carbon atoms, more preferably an alkyl acrylate selected from n-butyl acrylate, 2-ethylhexyl acrylate, and dodecyl acrylate. At least one of the group consisting of alkyl esters.

From the viewpoint of appropriately expressing basic properties such as adhesiveness in the adhesive layer 20, the ratio of the alkyl (meth)acrylate in the monomer component is preferably at least 50% by mass, more preferably at least 60% by mass. Furthermore, it is more preferable that it is 70 mass % or more. This ratio is, for example, 99% by mass or less.

The monomer component may also contain a copolymerizable monomer that can be copolymerized with an alkyl (meth)acrylate. As a copolymerizable monomer, the monomer which has a polar group is mentioned, for example. The polar group-containing monomer may, for example, be a monomer having a nitrogen atom ring, a hydroxyl group-containing monomer, or a carboxyl group-containing monomer. Polar group-containing monomers can be used to modify acrylic polymers, such as introducing crosslinking points into acrylic polymers, ensuring the cohesion of acrylic polymers, etc.

Monomers having a ring containing a nitrogen atom include, for example: N-vinyl-2-pyrrolidone, N-methylvinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N- Vinylpyrimidine, N-vinylpiperone, N-vinylpyrrole, N-vinylpyrrole, N-vinylimidazole, N-vinylpyrazole, N-(meth)acryl-2-pyrrole Pyridone, N-(meth)acrylpiperidine, N-(meth)acrylpyrrolidine, N-vinylmorpholine, N-vinyl-3-morpholinone, N-vinyl- 2-Caprolactam, N-Vinyl-1,3-㗁𠯤-2-one, N-Vinyl-3,5-Morpholinedione, N-Vinylpyrazole, N-Vinyliso㗁Azole, N-vinylthiazole, and N-vinylisothiazole. As a monomer having a ring containing a nitrogen atom, N-vinyl-2-pyrrolidone is preferably used.

From the viewpoint of ensuring the cohesion in the adhesive layer 20 and ensuring the adhesion of the adhesive layer 20 to the adherend, the ratio of the monomer having a nitrogen atom ring in the monomer component is preferably 0.1% by mass or more , more preferably at least 0.3% by mass, further preferably at least 0.55% by mass. From the viewpoint of adjusting the glass transition temperature of the acrylic polymer and adjusting the polarity of the acrylic polymer (related to the compatibility of various additive components in the adhesive layer 20 with the acrylic polymer), the ratio is preferably 30 mass % Below, more preferably below 20% by mass.

Examples of hydroxyl-containing monomers include: 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxyl (meth)acrylate Propyl ester, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, (methyl) ) 12-hydroxylauryl acrylate, and (4-hydroxymethylcyclohexyl)methyl (meth)acrylate. As the hydroxyl group-containing monomer, it is preferable to use 4-hydroxybutyl (meth)acrylate, more preferably to use 4-hydroxybutyl acrylate.

From the viewpoint of introducing a crosslinked structure into the acrylic polymer and ensuring cohesion in the adhesive layer 20, the proportion of the hydroxyl group-containing monomer in the monomer component is preferably at least 0.1% by mass, more preferably at least 0.5% by mass , and more preferably at least 0.8% by mass. From the viewpoint of adjusting the polarity of the acrylic polymer (related to the compatibility of various additive components in the adhesive layer 20 and the acrylic polymer), the ratio is preferably 20% by mass or less, more preferably 10% by mass or less.

Examples of carboxyl group-containing monomers include acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, and methacrylic acid.

From the viewpoint of introducing a cross-linked structure to the acrylic polymer, ensuring the cohesion in the adhesive layer 20, and ensuring the adhesion of the adhesive layer 20 to the adherend, the ratio of the carboxyl group-containing monomer in the monomer component is preferable. It is 0.1 mass % or more, More preferably, it is 0.5 mass % or more, More preferably, it is 0.8 mass % or more. From the viewpoint of adjusting the glass transition temperature of the acrylic polymer and avoiding the risk of corrosion of the adherend due to acid, the ratio is preferably at most 30% by mass, more preferably at most 20% by mass.

In order to prevent metal elements such as electrodes in the foldable device from being corroded by the acid component, the acid content of the adhesive layer 20 is preferably small. Also, when the adhesive layer 20 is used for bonding polarizing plates, the acid content of the adhesive layer 20 is preferably small in order to suppress polyeneization of the polyvinyl alcohol polarizing element caused by the acid component. The content of organic acid monomers (such as (meth)acrylic acid and carboxyl group-containing monomers) in the acid-free adhesive layer 20 is preferably less than 100 ppm, more preferably less than 70 ppm, and even more preferably 50 ppm. the following. The organic acid monomer content of the adhesive layer 20 can be obtained by immersing the adhesive layer 20 in pure water and heating it at 100° C. for 45 minutes to extract the acid monomer into the water, and Acid monomers were quantified using ion chromatography.

From the viewpoint of no acid, it is preferable that the base polymer in the adhesive layer 20 does not substantially contain an organic acid monomer as a monomer component. From the viewpoint of acid-free, the proportion of the organic acid monomer in the monomer component is preferably at most 0.5% by mass, more preferably at most 0.1% by mass, still more preferably 0.05% by mass, and most preferably 0% by mass.

The monomer component may also contain other copolymerizable monomers. Other copolymerizable monomers include acid anhydride monomers, sulfonic acid-containing monomers, phosphoric acid-containing monomers, epoxy-containing monomers, cyano-containing monomers, alkoxy-containing monomers, and aromatic vinyl base compound. These other copolymerizable monomers may be used alone or in combination of two or more.

In this embodiment, the base polymer has a cross-linked structure. The method of introducing a cross-linked structure into the base polymer can be exemplified by formulating the base polymer with a functional group capable of reacting with the cross-linking agent and the cross-linking agent into the first adhesive composition, and making the base polymer and the cross-linking agent A method in which the agent reacts in the adhesive layer 20 (the first method); and the monomer component forming the base polymer includes a multifunctional monomer and the polymer chain is formed by polymerization of the monomer component to introduce a branched chain The method (the second method) of the base polymer of the structure (cross-linked structure). These methods can also be used in combination.

Examples of the crosslinking agent used in the above-mentioned first method include compounds that react with functional groups (hydroxyl groups, carboxyl groups, etc.) contained in the base polymer. Such a crosslinking agent may, for example, be an isocyanate crosslinking agent, a peroxide crosslinking agent, an epoxy crosslinking agent, an azoline crosslinking agent, an aziridine crosslinking agent, a carbodiimide crosslinking agent, And metal chelate crosslinking agent. A crosslinking agent may be used individually or in combination of 2 or more types. In terms of high reactivity with the hydroxyl and carboxyl groups in the base polymer and the ease of introducing a crosslinked structure, the crosslinking agent is preferably an isocyanate crosslinking agent, a peroxide crosslinking agent, and an epoxy crosslinking agent. agent.

The isocyanate crosslinking agent may, for example, be exemplified: toluene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diisocyanate, Benzene diisocyanate, tetramethylxylylene diisocyanate, naphthalene diisocyanate, triphenylmethane triisocyanate, and polymethylene polyphenylisocyanate. Moreover, derivatives of these isocyanate can also be mentioned as an isocyanate crosslinking agent. As this isocyanate derivative, a modified isocyanurate and a modified polyol are mentioned, for example. Examples of commercially available isocyanate crosslinking agents include: Coronate L (trimethylolpropane adduct of toluene diisocyanate, manufactured by Tosoh), Coronate HL (trimethylolpropane adduct of hexamethylene diisocyanate) product, manufactured by Tosoh), Coronate HX (isocyanurate body of hexamethylene diisocyanate, manufactured by Tosoh), and Takenate D110N (trimethylolpropane adduct of xylylene diisocyanate, manufactured by Mitsui Chemicals ).

The peroxide crosslinking agent can be exemplified: dibenzoyl peroxide, bis(2-ethylhexyl) peroxydicarbonate, bis(4-tert-butylcyclohexyl) peroxydicarbonate, peroxydicarbonate Di-2-butyl dicarbonate, tert-butyl peroxyneodecanoate, tert-hexyl peroxypivalate, and tert-butyl peroxypivalate.

Examples of epoxy crosslinking agents include: bisphenol A, epichlorohydrin type epoxy resin, vinyl glycidyl ether, polyethylene glycol diglycidyl ether, glycerol diglycidyl ether, glycerol triglycidyl ether, 1,6 -Hexanediol Glycidyl Ether, Trimethylolpropane Triglycidyl Ether, Diglycidylaniline, Diamine Glycidylamine, N,N,N',N'-Tetraglycidyl m-xylylenediamine, and 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane.

From the viewpoint of ensuring appropriate flexibility (thereby having flexibility) of the adhesive layer 20 , an isocyanate crosslinking agent (especially a difunctional isocyanate crosslinking agent) and a peroxide crosslinking agent are preferable. From the viewpoint of securing the durability of the adhesive layer 20, an isocyanate crosslinking agent (especially a trifunctional isocyanate crosslinking agent) is preferable. In the base polymer, difunctional isocyanate crosslinkers and peroxide crosslinkers form softer two-dimensional crosslinks, while trifunctional isocyanate crosslinkers form stronger three-dimensional crosslinks. From the viewpoint of achieving both durability and flexibility of the adhesive layer 20 , it is preferable to use a trifunctional isocyanate crosslinking agent, a peroxide crosslinking agent and/or a difunctional isocyanate crosslinking agent in combination.

From the viewpoint of securing the cohesive force of the adhesive layer 20 , the compounded amount of the crosslinking agent is, for example, 0.01 parts by mass or more, preferably 0.05 parts by mass or more, more preferably 0.07 parts by mass or more, based on 100 parts by mass of the base polymer. From the viewpoint of ensuring good adhesiveness in the adhesive layer 20, the blending amount of the crosslinking agent relative to 100 parts by mass of the base polymer is, for example, 10 parts by mass or less, preferably 5 parts by mass or less, more preferably 3 parts by mass. Parts by mass or less.

In the above-mentioned second method, monomer components (including polyfunctional monomers and other monomers for introducing a crosslinked structure) may be polymerized at one time or in multiple stages. In the method of multi-stage polymerization, first, polymerization (pre-polymerization) is carried out using monofunctional monomers to form the base polymer, thereby preparing a mixture containing part of the polymer (polymer with a low degree of polymerization and unreacted monomer ) of the prepolymer composition. Next, after adding the polyfunctional monomer to the prepolymer composition, a part of the polymer is polymerized with the polyfunctional monomer (main polymerization).

As a polyfunctional monomer, the polyfunctional (meth)acrylate which has 2 or more ethylenically unsaturated double bonds in 1 molecule is mentioned, for example. From the viewpoint that a crosslinked structure can be introduced by active energy ray polymerization (photopolymerization), the polyfunctional monomer is preferably a polyfunctional acrylate.

The multifunctional (meth)acrylate may, for example, be a bifunctional (meth)acrylate, a trifunctional (meth)acrylate, or a tetrafunctional or higher polyfunctional (meth)acrylate.

Difunctional (meth)acrylates can be exemplified, for example: ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, Diol Dimethacrylate, 1,6-Hexanediol Di(meth)acrylate, 1,9-Nanediol Di(meth)acrylate, Glycerin Di(meth)acrylate, Neopentyldiol Alcohol di(meth)acrylate, stearic acid modified pentaerythritol di(meth)acrylate, dicyclopentenyl diacrylate, isocyanuric acid di(meth)acryl ester, and alkylene oxide modified Bisphenol di(meth)acrylate.

Trifunctional (meth)acrylates may, for example, be trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, or tri(acryloxyethyl)isocyanurate.

Examples of polyfunctional (meth)acrylates with four or more functions include di-trimethylolpropane tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, and dipentaerythritol monohydroxypenta(meth)acrylate. ester, alkyl-modified dipentaerythritol pentaacrylate, and dipentaerythritol hexa(meth)acrylate.

The molecular weight of the polyfunctional monomer is preferably 1500 or less, more preferably 1000 or less. Moreover, the functional group equivalent (g/eq) of a polyfunctional monomer becomes like this. Preferably it is 50 or more, More preferably, it is 70 or more, More preferably, it is 80 or more. The functional group equivalent weight is preferably 500 or less, more preferably 300 or less, further preferably 200 or less. These constitutions are preferable from the viewpoint of appropriately adjusting viscoelasticity (for example, storage modulus G' and loss tangent tanδ) by introducing a crosslinked structure into the base polymer.

An acrylic polymer can be formed by polymerizing the above monomer components. The polymerization method may, for example, be solution polymerization, active energy ray polymerization (such as ultraviolet polymerization), bulk polymerization, or emulsion polymerization. From the viewpoints of transparency, water resistance, and cost of the adhesive layer 20, solution polymerization and ultraviolet polymerization are preferable. As a solvent for solution polymerization, ethyl acetate and toluene can be used, for example. Moreover, as a polymerization initiator, a thermal polymerization initiator and a photopolymerization initiator can be used, for example. The usage-amount of a polymerization initiator is 0.05 mass part or more with respect to 100 mass parts of monomer components, and is, for example, 1 mass part or less.

As a thermal polymerization initiator, an azo polymerization initiator and a peroxide polymerization initiator are mentioned, for example. Examples of azo polymerization initiators include: 2,2'-azobisisobutyronitrile, 2,2'-azobis-2-methylbutyronitrile, 2,2'-azobis(2- Dimethyl methylpropionate, 4,4'-azobis-4-cyanovaleric acid, azobisisovaleronitrile, 2,2'-azobis(2-amidinopropane) dihydrochloride Salt, 2,2'-Azobis[2-(5-methyl-2-imidazolin-2-yl)propane] dihydrochloride, 2,2'-Azobis(2-methylpropionamidine ) disulfate, and 2,2'-azobis(N,N'-dimethyleneisobutyramide) dihydrochloride. The peroxide polymerization initiator may, for example, be dibenzoyl peroxide, tert-butyl peroxymaleate, or lauryl peroxide.

光聚合起始劑、及醯基氧化膦光聚合起始劑。The photopolymerization initiator may, for example, be benzoin ether photopolymerization initiator, acetophenone photopolymerization initiator, α-ketol photopolymerization initiator, aromatic sulfonyl chloride photopolymerization initiator, photoactive Oxime Photopolymerization Initiator, Benzoin Photopolymerization Initiator, Benzophenone Photopolymerization Initiator, Benzophenone Photopolymerization Initiator, Ketal Photopolymerization Initiator, 9-Oxysulfur

A photopolymerization initiator, and an acyl phosphine oxide photopolymerization initiator.

During the polymerization, a chain transfer agent and/or a polymerization inhibitor (polymerization retarder) can also be used for molecular weight adjustment and the like. Examples of chain transfer agents include: α-thioglycerol, lauryl mercaptan, glycidyl mercaptan, thioglycolic acid, 2-mercaptoethanol, thioglycolic acid, 2-ethylhexyl thioglycolic acid, 2,3 - Dimercapto-1-propanol, and α-methylstyrene dimer.

The molecular weight of the base polymer can be adjusted by adjusting the type and/or amount of the polymerization initiator. For example, in free radical polymerization, the more the amount of polymerization initiator is, the higher the concentration of free radicals in the reaction system is, so the density of reaction starting points tends to be higher and the molecular weight of the formed base polymer tends to decrease. On the other hand, the smaller the amount of the polymerization initiator, the lower the density of the reaction starting point, so the polymer chain tends to be easily extended, and the molecular weight of the formed base polymer tends to increase.

The weight average molecular weight of the acrylic polymer is preferably at least 100,000, more preferably at least 300,000, and still more preferably at least 500,000, from the viewpoint of ensuring cohesion in the adhesive layer 20 . The weight average molecular weight is preferably at most 5 million, more preferably at most 3 million, further preferably at most 2 million. The weight-average molecular weight of the acrylic polymer was measured by gel permeation chromatography (GPC) and calculated in terms of polystyrene.

The glass transition temperature (Tg) of the base polymer is preferably 0°C or lower, more preferably -10°C or lower, further preferably -20°C or lower. The glass transition temperature is, for example, -80°C or higher.

Regarding the glass transition temperature (Tg) of the base polymer, the glass transition temperature (theoretical value) obtained based on the following Fox formula can be used. The Fox formula is a relationship between the glass transition temperature Tg of a polymer and the glass transition temperature Tgi of a homopolymer of monomers constituting the polymer. In the following Fox formula, Tg represents the glass transition temperature (°C) of the polymer, Wi represents the weight fraction of monomer i constituting the polymer, and Tgi represents the glass transition temperature of the homopolymer formed by monomer i (℃). The glass transition temperature of the homopolymer can use the literature value. For example, "Polymer Handbook" (4th edition, John Wiley & Sons, Inc., 1999) and "New Polymer Library 7 Introduction to Synthetic Resins for Coatings" (Kyo Kitaoka, Polymer Publishing Association, 1995) List the glass transition temperatures of various homopolymers. On the other hand, the glass transition temperature of the homopolymer of the monomer can also be obtained by the method specifically described in JP-A-2007-51271.

Fox formula 1/(273+Tg)=Σ[Wi/(273+Tgi)]

In addition to the base polymer, the first adhesive composition may also contain one or two or more oligomers. In the case of using an acrylic polymer as the base polymer, it is preferable to use an acrylate oligomer as the oligomer. The acrylate oligomer is a copolymer containing a monomer component of an alkyl (meth)acrylate in a ratio of 50% by mass or more, and has a weight average molecular weight of, for example, 1,000 to 30,000.

The glass transition temperature of the acrylate oligomer is preferably at least 60°C, more preferably at least 80°C, still more preferably at least 100°C, especially preferably at least 110°C. The glass transition temperature of the acrylate oligomer is, for example, below 200°C, preferably below 180°C, more preferably below 160°C. By using a low Tg acrylic polymer (base polymer) with a crosslinked structure and a high Tg acrylate oligomer in combination, the adhesive force of the adhesive layer 20, especially the adhesive force at high temperature, can be improved. The glass transition temperature of the acrylate oligomer is calculated by the above-mentioned Fox formula.

The acrylate oligomer having a glass transition temperature of 60° C. or higher preferably contains an alkyl (meth)acrylate (chain alkyl (meth)acrylate) with a chain alkyl group and an alicyclic alkyl group. A polymer of monomer components of alkyl (meth)acrylate (cycloalkyl (meth)acrylate). Specific examples of these alkyl (meth)acrylates include the above-mentioned alkyl (meth)acrylates as monomer components of acrylic polymers.

The chain alkyl (meth)acrylate is preferably methyl methacrylate in terms of a high glass transition temperature and excellent compatibility with the base polymer. The alicyclic alkyl (meth)acrylate is preferably dicyclopentyl acrylate, dicyclopentyl methacrylate, cyclohexyl acrylate, and cyclohexyl methacrylate. That is, the acrylate oligomer preferably contains one or more kinds selected from the group consisting of dicyclopentyl acrylate, dicyclopentyl methacrylate, cyclohexyl acrylate, and cyclohexyl methacrylate, and methyl Polymer of monomer component of methyl acrylate.

The ratio of the alicyclic alkyl (meth)acrylate in the monomer component of the acrylate oligomer is preferably at least 10% by weight, more preferably at least 20% by weight, and still more preferably at least 30% by weight. The ratio is preferably at most 90% by weight, more preferably at most 80% by weight, further preferably at most 70% by weight. The proportion of the chain alkyl (meth)acrylate in the monomer component of the acrylate oligomer is preferably at most 90% by weight, more preferably at most 80% by weight, further preferably at most 70% by weight. The ratio is preferably at least 10% by weight, more preferably at least 20% by weight, and still more preferably at least 30% by weight.

The weight average molecular weight of the acrylate oligomer is preferably at least 1,000, more preferably at least 1,500, and still more preferably at least 2,000. The molecular weight is preferably at most 30000, more preferably at most 10000, still more preferably at most 8000. The molecular weight range of the acrylate oligomer is preferable to ensure the adhesion and adhesion of the adhesive layer 20 .

The acrylate oligomer is obtained by polymerizing the monomer components of the acrylate oligomer. The polymerization method may, for example, be solution polymerization, active energy ray polymerization (such as ultraviolet polymerization), bulk polymerization, or emulsion polymerization. In the polymerization of the acrylate oligomer, a polymerization initiator can also be used, or a chain transfer agent can also be used to adjust the molecular weight.

In order to fully improve the adhesion of the adhesive layer 20, the content of the acrylate oligomer in the adhesive layer 20 is preferably at least 0.5 parts by mass, more preferably at least 0.8 parts by mass, and even more preferably 100 parts by mass of the base polymer. Preferably, it is at least 1 part by mass. On the other hand, from the viewpoint of ensuring the transparency of the adhesive layer 20, the content of the acrylate oligomer in the adhesive layer 20 is preferably 5 parts by mass or less with respect to 100 parts by mass of the base polymer, more preferably 5 parts by mass or less. 4 parts by mass or less, more preferably 3 parts by mass or less. When the content of the acrylate oligomer in the pressure-sensitive adhesive layer 20 is too large, the haze tends to increase due to the decrease in compatibility of the acrylate oligomer, and the transparency tends to decrease.

The first adhesive composition may also contain a silane coupling agent. The content of the silane coupling agent in the first adhesive composition is preferably at least 0.1 parts by mass, more preferably at least 0.2 parts by mass, based on 100 parts by mass of the base polymer. The content is preferably at most 5 parts by mass, more preferably at most 3 parts by mass.

The 1st adhesive composition may contain other components as needed. Other components include, for example, an adhesion imparting agent, a plasticizer, a softener, an anti-deterioration agent, a filler, a colorant, an ultraviolet absorber, an antioxidant, a surfactant, and an antistatic agent.

From the viewpoint of ensuring sufficient adhesiveness to the adherend, the thickness H of the adhesive layer 20 is preferably 10 μm or more, more preferably 15 μm or more. From the viewpoint of handleability, the thickness H is preferably at most 300 μm, more preferably at most 200 μm, still more preferably at most 100 μm, and most preferably at most 50 μm.

The ratio (d1/H) of the first relief length d1 to the thickness H is preferably at least 0.4, more preferably at least 0.6. The ratio (d1/H) is preferably 8 or less, more preferably 6 or less. These configurations are suitable for fully rolling up the end portion of the easy release film 40 (the above-mentioned free portion) before pulling the easy release film 40 away from the end edge 22 of the adhesive layer 20 during the peeling start of the easy release film 40. 40a) to deform it, and therefore, can preferably be used to reduce the force required for the peeling initiation of the light release film 40 .

The haze of the adhesive layer 20 is preferably 3% or less, more preferably 2% or less, more preferably 1% or less. The haze of the adhesive layer 20 can be measured using a haze meter according to JIS K7136 (2000). Examples of the haze meter include "NDH2000" manufactured by Nippon Denshoku Industries Co., Ltd. and "HM-150" manufactured by Murakami Color Technology Laboratory.

The total light transmittance of the adhesive layer 20 is preferably at least 60%, more preferably at least 80%, and still more preferably at least 85%. The total light transmittance of the adhesive layer 20 is, for example, 100% or less. The total light transmittance of the adhesive layer 20 can be measured according to JIS K 7375 (2008).

The adhesive layer 30 is a pressure-sensitive adhesive layer formed from the second adhesive composition. The adhesive layer 30 has transparency. The second adhesive composition contains at least a base polymer. The base polymer contained in the second adhesive composition may, for example, be the base polymer described above regarding the first adhesive composition. The base polymer in the first adhesive composition and the base polymer in the second adhesive composition may be the same or different. The second adhesive composition may contain components other than the base polymer. The components contained in the second adhesive composition include, for example, the components other than the base polymer described above about the first adhesive composition. The composition of the first adhesive composition and the composition of the second adhesive composition may be the same or different. From the viewpoint of adjusting the above-mentioned peeling initiation forces F1, F2 and peeling forces f1, f2, it is preferable that the composition of the first adhesive composition is different from the composition of the second adhesive composition.

The thickness of the adhesive layer 30 may be the same as that of the adhesive layer 20 or different. From the viewpoint of ensuring sufficient adhesiveness to the adherend, the thickness of the adhesive layer 30 is preferably 10 μm or more, more preferably 15 μm or more. From the viewpoint of handleability, the thickness of the adhesive layer 30 is preferably 300 μm or less, more preferably 200 μm or less, further preferably 100 μm or less, especially preferably 50 μm or less. Moreover, the ratio of the thickness of the adhesive layer 30 to the thickness of the adhesive layer 20 is 0.2 or more, for example, and 5 or less, for example.

The haze of the adhesive layer 30 is preferably 3% or less, more preferably 2% or less, and still more preferably 1% or less. The haze of the adhesive layer 30 can be measured using a haze meter according to JIS K7136 (2000).

The total light transmittance of the adhesive layer 30 is preferably at least 60%, more preferably at least 80%, and still more preferably at least 85%. The total light transmittance of the adhesive layer 30 is, for example, 100% or less. The total light transmittance of the adhesive layer 30 can be measured according to JIS K 7375 (2008).

The light release film 40 can be, for example, a flexible plastic film. The plastic film may, for example, be a polyethylene terephthalate film, a polyethylene film, a polypropylene film, or a polyester film. The thickness of the light release film 40 is preferably at least 5 μm, more preferably at least 10 μm, and is preferably at most 200 μm, more preferably at most 150 μm. The surface of the light release film 40 is preferably peeled off. The peeling treatment may, for example, be a silicone peeling treatment or a fluorine peeling treatment (the same applies to the peeling treatment described later). The above-mentioned first peeling initiation force F1 and peeling force f1 related to the peeling of the light peeling film 40 from the adhesive layer 20 can be adjusted by the presence or absence of peeling treatment, selection of the type, and adjustment of conditions.

The heavy release film 50 can, for example, be the plastic film described above with respect to the light release film 40 . The thickness of the heavy release film 50 is preferably at least 5 μm, more preferably at least 10 μm, and is preferably at most 200 μm, more preferably at most 150 μm. The surface of the heavy peeling film 50 is preferably peeled off. The above-mentioned second peeling start force F2 and peeling force f2 related to the peeling of the heavy peeling film 50 from the adhesive layer 30 can be adjusted by the presence or absence of peeling treatment, selection of the type, and adjustment of conditions.

The optical film X can be manufactured as follows, for example.

First, the optical film 10 , the adhesive layer 20 with the light release film 40 , and the adhesive layer 30 with the heavy release film 50 are prepared (preparatory step).

The adhesive layer 20 with the light release film 40 can be formed by coating the first adhesive composition (varnish) on the light release film 40 to form a coating film, and then drying the coating film. The coating method of the first adhesive composition is, for example, roll coating, touch roll coating, gravure coating, reverse coating, roll brush coating, spray coating, dip roll coating, rod coating, etc. Coating, blade coating, air knife coating, curtain coating, die lip coating, and die coating (the method of coating the second adhesive composition described later is also the same). It is also possible to laminate other release films on the adhesive layer 20 on the light release film 40 . The peeling film is peeled before the bonding of the optical film 10 and the adhesive layer 20 .

The adhesive layer 30 with the heavy release film 50 can be formed by coating the second adhesive composition (varnish) on the heavy release film 50 to form a coating film, and then drying the coating film. It is also possible to laminate other release films on the adhesive layer 30 on the heavy release film 50 . The peeling film is peeled before the bonding of the optical film 10 and the adhesive layer 30 .

Next, the first surface 11 of the optical film 10 is bonded to the adhesive layer 20 side of the adhesive layer 20 with the light release film 40 (first bonding step). Next, the second surface 12 of the optical film 10 is bonded to the adhesive layer 30 side of the adhesive layer 30 with the heavy release film 50 (second bonding step). Thereby, the laminated body which is the optical film X with the outer peripheral end unprocessed was obtained. Preferably, the first surface 11 and the second surface 12 of the optical film 10, the exposed surface of the adhesive layer 20 with the light release film 40, and the adhesive with the heavy release film 50 are The exposed surface of layer 30 is plasma treated.

Next, the laminated body is held in the thickness direction by the jig for clamping, and the laminated body is aligned with the jig in the thickness direction in such a way that each adhesive layer 20, 30 elastically deforms and protrudes from the side end surface of the laminated body to a certain extent. The applied pressure is adjusted (pressurized holding step). By adjusting the pressure, the degree of elastic deformation of the adhesive layer 20, 30 can be adjusted, therefore, the length protruding from the side end surface of the laminate can be adjusted.

Next, in the state where the adhesive layer 20, 30 is elastically deformed in such a way that it protrudes from the side end surface of the laminate, it is cut in the thickness direction by a rotary knife on the inner side of a certain length from the side end surface of the laminate, so as to re- All or part of the outer periphery of the laminate is formed (cutting step). The above-mentioned specific length is, for example, 0.1 mm or more, and, for example, 1 mm or less. Then, the pressurized state of the laminate formed by the jig is released. Thereby, the adhesive layer 20, 30 undergoes elastic recovery, and the edge 22, 32 of the adhesive layer 20, 30 is in the in-plane direction D than the edge 13 of the optical film 10, the light release film 40, and the heavy release film 50. , 42, 52 backed away towards the inside. In this way, the side concave-convex end portion E is formed.

In this cutting step, by adjusting the pressure applied to the laminate in the thickness direction, the length of the adhesive layer 20, 30 protruding from the side end surface of the laminate can be adjusted, and the pressure can be adjusted after the pressurized state is released. The back-off lengths d1, d2 of the end edges 22, 32. Moreover, as mentioned above, the adjustment method of the 1st back-off length d1 can also illustrate the adjustment of the thickness of the adhesive layer 20, and the adjustment of elastic modulus. As mentioned above, the adjustment method of the 2nd back-off length d2 can also exemplify the adjustment of the thickness of the adhesive layer 30, and the adjustment of elastic modulus. Also, as mentioned above, the method of adjusting the distance between the edges 22 and 32 in the in-plane direction D (that is, the difference between the first relief length d1 and the second relief length d2) can be exemplified in order to form the concave-convex end portion E of the side surface. The adjustment of cutting conditions in the cutting step described later is carried out using a rotary knife. The cutting conditions include, for example, the taper angle of the blade tip of the rotary blade, the rotational speed of the rotary blade, the incident direction of the rotary blade relative to the surface of the optical film laminate described later, and the displacement speed of the rotary blade for cutting the optical film laminate.

The above-mentioned optical film X (optical film with release film) can be manufactured in the above-mentioned manner.

In the above preparation steps, the release film for the first step can also be used instead of the light release film 40 to prepare the adhesive layer 20 with the release film for the first step, and the release film for the second step can also be used instead of the heavy release film. The film 50 is used to prepare the adhesive layer 30 with the release film for the second step. In this case, in the above-mentioned first bonding step, the first surface 11 of the optical film 10 is bonded to the adhesive layer 20 side of the adhesive layer 20 with the release film for the first step. Also, in the second bonding step, the second surface 12 of the optical film 10 is bonded to the adhesive layer 30 side of the adhesive layer 30 with a release film for the second step (before bonding, preferably implementation of the plasma treatment described above). Thereby, the laminated body provided with the release film for 1st process, the adhesive layer 20, the optical film 10, the adhesive layer 30, and the release film for 2nd process in this order in the thickness direction is obtained. Next, in this laminated body, after the release film is used in the first step to self-adhesive layer 20, the light release film 40 is attached to the exposed surface of the adhesive layer 20, and after the release film is used in the second step to self-adhesive After the layer 30 is peeled off, the heavy release film 50 is pasted on the exposed surface of the adhesive layer 30 . A laminated body as the optical film X can also be obtained with the outer peripheral edge unprocessed in the above manner. Thereafter, the above-mentioned pressure holding step and cutting step can be performed on the laminated body, whereby the optical film X (optical film with release film) can be produced.

In the manufacturing process of the optical film X, in the first bonding step, the adhesive layer 20 with the release film for the first step can be bonded to the first surface 11 of the optical film 10, and can be bonded in the second bonding step. In the bonding step, the adhesive layer 30 with the heavy release film 50 is bonded to the second surface 12 of the optical film 10 (before bonding, the above-mentioned plasma treatment is preferably performed). Thereby, the laminated body provided with the release film for 1st process, the adhesive layer 20, the optical film 10, the adhesive layer 30, and the heavy release film 50 in the thickness direction is obtained. Next, in this laminated body, after peeling the release film for the first step from the adhesive layer 20 , the light release film 40 is bonded to the exposed surface of the adhesive layer 20 . A laminated body as the optical film X can also be obtained with the outer peripheral edge unprocessed in the above manner. Thereafter, the above-mentioned pressure holding step and cutting step can be performed on the laminated body, whereby the optical film X (optical film with release film) can be produced.

In the manufacturing process of the optical film X, in the first bonding step, the adhesive layer 20 with the light release film 40 can be bonded to the first surface 11 of the optical film 10, and in the second bonding step In this process, the adhesive layer 30 with the release film for the second step is bonded to the second surface 12 of the optical film 10 (before bonding, it is preferable to perform the above-mentioned plasma treatment). Thereby, the laminated body provided with the light release film 40, the adhesive layer 20, the optical film 10, the adhesive layer 30, and the release film for 2nd steps in this order in the thickness direction is obtained. Next, in this laminated body, after peeling off the release film for the 2nd step from the adhesive layer 30, the heavy release film 50 is bonded to the exposed surface of the adhesive layer 30. A laminated body as the optical film X can also be obtained with the outer peripheral edge unprocessed in the above manner. Thereafter, the above-mentioned pressure holding step and cutting step can be performed on the laminated body, whereby the optical film X (optical film with release film) can be produced.

In the manufacturing process of the optical film X, a photocurable adhesive composition may also be used as the adhesive composition to form the adhesive layers 20 and 30 . The photocurable adhesive composition may, for example, be an ultraviolet curable adhesive composition that undergoes polymerization reaction of a monomer component by being irradiated with ultraviolet rays. For example, when using a photocurable adhesive composition as a 2nd adhesive composition, first, apply this 2nd adhesive composition on the peeling film for 2nd steps, and form a coating film. Next, a heavy release film 50 is laminated on the coating film on the release film for the second step. Next, the coating film is photocured by irradiating light of a specific wavelength (ultraviolet rays, etc.) to the coating film between release films. Thereby, the adhesive layer 30 is formed between the release films. Next, the adhesive layer 30 on the peeling film 50 by its own weight is peeled off from the second-step peeling film. The adhesive layer 30 with the heavy release film 50 obtained in this way can also be used to carry out the above-mentioned second bonding step.

An example of the usage method of the optical film X is shown in FIG. 3A to FIG. 3D.

In this method, first, as shown in FIG. 3A , the light release film 40 is peeled off from the pressure-sensitive adhesive layer 20 of the optical film X. For example, in the state where the heavy release film 50 side of the optical film X is fixed on the table, a force is applied to the end of the light release film 40 in the side concave-convex end portion E to peel the light release film from the adhesive layer 20. 40. Thereby, the adhesive surface 21 of the adhesive layer 20 is exposed.

As described above, in the in-plane direction D in the concave-convex end portion E, the edge 22 of the adhesive layer 20 is smaller than the edges 13, 42, 52 of the optical film 10, the light release film 40, and the heavy release film 50. retreat. As described above with reference to FIG. 2 , in such a side concave-convex end portion E, the light release film 40 has a free portion 40 a to which the adhesive layer 20 is not bonded. Therefore, when peeling the light release film 40 from the adhesive layer 20 at the side uneven end part E, first, the free part 40a of the light release film 40 can be deformed by rolling up as shown by phantom lines in FIG. Then stretch the rolled and deformed free portion 40 a to pull the light release film 40 away from the end edge 22 of the adhesive layer 20 . That is, in the process of starting the peeling, it is not necessary to simultaneously apply a force (first force) for sufficiently deforming the free portion 40a of the light release film 40 and an adhesive force for elastically deforming the light release film 40 following the deformation. The edge 22 of the agent layer 20 pulls the light release film 40 away (the second force). Such an optical film X is suitable for reducing the force required for the peel initiation process. The smaller the force, the more it is possible to suppress the deformation of the optical film 10 whose thickness is as thin as 100 μm or less in the process of starting the peeling of the light release film 40, thereby also suppressing the deformation of the adhesive layer 30. Therefore, the adhesive layer 30 can be suppressed. The end edge 32 is separated from the weight release film 50 .

In addition, as shown in FIG. 2 , in the side concave-convex end portion E, the first relief length d1 is smaller than the second relief length d2. That is, the edge 32 of the adhesive layer 30 is receded from the edge 22 of the adhesive layer 20 in the in-plane direction D in the concave-convex end portion E of the side surface. This configuration is suitable for suppressing the adhesive when the above-mentioned second force for pulling the easy-release film 40 away from the edge 22 of the adhesive layer 20 acts on the optical film X in the process of starting the peeling of the easy-release film 40 . Deformation of layer 30 is, therefore, adapted to inhibit separation of edge 32 of adhesive layer 30 from weight release film 50 .

Next, as shown in FIG. 3B , the optical film 10 and the first member M1 (first adherend) are bonded via the adhesive layer 20 . The first member M1 is, for example, one element of the laminated structure of the flexible panel. This element may, for example, be a pixel panel, a touch panel, or a transparent cover film (the same applies to the second member M2 described later).

Next, as shown in FIG. 3C , the heavy release film 50 is peeled off from the adhesive layer 30 . Thereby, the adhesive surface 31 of the adhesive layer 30 is exposed.

Next, as shown in FIG. 3D , the optical film 10 and the second member M2 (second adherend) are bonded via the adhesive layer 30 .

In the manufacturing process of, for example, a flexible panel, the optical film X is used in the above-mentioned manner. [Example]

Hereinafter, an Example is shown and this invention is demonstrated concretely. This invention is not limited to an Example. In addition, the specific numerical values of the blending amount (content), physical property values, parameters, etc. described below may be the upper limit of the blending amount (content), physical property values, parameters, etc. corresponding to the above-mentioned "embodiment" (defined as "below" or "under" value) or lower limit (defined as "above" or "over" value) instead.

[Example 1] ＜Production of the first adhesive sheet＞ The 1st adhesive sheet in Example 1 was produced in the following manner.

＜Preparation of acrylate oligomer＞ In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas introduction tube, 95 parts by mass of cyclohexyl methacrylate (CHMA), 5 parts by mass of acrylic acid (AA), and α-methanol as a chain transfer agent A mixture of 10 parts by mass of styrene dimer and 120 parts by mass of toluene as a solvent was stirred at room temperature under a nitrogen atmosphere for 1 hour. Subsequently, 10 parts by mass of 2,2'-azobisisobutyronitrile (AIBN) was added to the mixture as a thermal polymerization initiator to prepare a reaction solution, and the reaction was carried out at 85° C. for 5 hours under a nitrogen atmosphere (acrylic acid formation of ester oligomers). Thereby, the oligomer solution (50 mass % of solid content concentration) containing an acrylate oligomer was obtained. The weight average molecular weight of the acrylate oligomer was 4300. Moreover, the glass transition temperature (Tg) of an acrylate oligomer was 84 degreeC.

＜Preparation of the first acrylic base polymer＞ In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen inlet tube, 70 parts by mass of 2-ethylhexyl acrylate (2EHA), 20 parts by mass of n-butyl acrylate (BA), 20 parts by mass of n-butyl acrylate, lauryl acrylate ( LA) 8 parts by mass, 4-hydroxybutyl acrylate (4HBA) 1 part by mass, N-vinyl-2-pyrrolidone (NVP) 0.6 parts by mass, 2,2'-azo as a thermal polymerization initiator A mixture (solid content concentration: 47% by mass) of 0.1 parts by mass of diisobutyronitrile (AIBN) and ethyl acetate as a solvent was stirred at 56° C. under a nitrogen atmosphere for 6 hours (polymerization reaction). Thereby, the 1st polymer solution containing the 1st acrylic base polymer was obtained. The weight average molecular weight of the first acrylic base polymer in the polymer solution was about 2 million.

<Preparation of the first adhesive composition> To the first polymer solution, 1.5 parts by mass of an acrylate oligomer and a first crosslinking agent (product name "Nyper BMT-40SV", diphenyl peroxide formyl, manufactured by NOF) 0.26 parts by mass, a second crosslinking agent (product name "Coronate L", trimethylolpropane/toluene diisocyanate trimer adduct, manufactured by Tosoh) 0.02 parts by mass, and silane diisocyanate A mixture (product name "KBM403", manufactured by Shin-Etsu Chemical Co., Ltd.) was mixed with 0.3 parts by mass to prepare a first adhesive composition.

＜Formation of the first adhesive sheet＞ The first adhesive composition was applied to the release-treated surface of the release film L1 which had been subjected to a silicone release treatment on one side to form a coating film. The release film L1 is a polyethylene terephthalate (PET) film (product name "DIAFOIL MRF50", thickness 50 μm, manufactured by Mitsubishi Chemical) that has undergone silicone release treatment on one side. Next, the release-treated surface of the release film L2 that has been subjected to silicone release treatment on one side is bonded to the coating film on the release film L1. The release film L2 is a PET film (product name "DIAFOIL MRV75", thickness 75 μm, manufactured by Mitsubishi Chemical) that has undergone silicone release treatment on one side. Next, heat the coating film sandwiched between the release film L1 and the release film L2 at 100°C for 1 minute, and then heat at 150°C for 3 minutes to dry the coating film and form a transparent first adhesive layer with a thickness of 50 μm The first adhesive sheet formed. The 1st adhesive sheet with the peeling film L1, L2 was produced in the above-mentioned manner.

＜Production of the second adhesive sheet＞ The 2nd adhesive sheet in Example 1 was produced in the following manner.

＜Preparation of the second acrylic base polymer＞ In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas introduction pipe, 99 parts by mass of butyl acrylate (BA), 1 part by mass of 4-hydroxybutyl acrylate (4HBA), as a thermal polymerization initiator A mixture of 0.3 parts by mass of 2,2'-azobisisobutyronitrile (AIBN) and ethyl acetate as a solvent was stirred at 60° C. for 4 hours under a nitrogen atmosphere (polymerization reaction). Thereby, the 2nd polymer solution containing the 2nd acrylic base polymer was obtained. The weight average molecular weight of the second acrylic base polymer in this polymer solution was 1.65 million.

＜Preparation of the second adhesive composition＞ To the second polymer solution, 0.3 parts by mass of the first crosslinking agent (product name "Nyper BMT-40SV", dibenzoyl peroxide, manufactured by NOF) was added to 100 parts by mass of the solid content of the polymer solution. Parts, 0.1 parts by mass of the third crosslinking agent (product name "Takenate D110N", trimethylolpropane xylylene diisocyanate, manufactured by Mitsui Chemicals), and a silane coupling agent (product name "KBM403", manufactured by Shin-Etsu Chemical Co., Ltd. ) 0.3 parts by mass and mixed to prepare the second adhesive composition.

＜Formation of the second adhesive sheet＞ A coating film was formed by applying the second adhesive composition on the release-treated surface of the release film L3 which had been subjected to a silicone release treatment on one side. The release film L3 is a polyethylene terephthalate (PET) film (product name "DIAFOIL MRF50", thickness 50 μm, manufactured by Mitsubishi Chemical) that has undergone silicone release treatment on one side. Next, the release-treated surface of the release film L4 that has been subjected to silicone release treatment on one side is bonded to the coating film on the release film L3. The release film L4 is a PET film (product name "DIAFOIL MRV75", thickness 75 μm, manufactured by Mitsubishi Chemical) with one side treated with silicone release. Next, heat the coating film sandwiched between the release film L3 and the release film L4 at 100°C for 1 minute, and then heat at 150°C for 3 minutes to dry the coating film and form a transparent second adhesive layer with a thickness of 50 μm The second adhesive sheet formed. The 2nd adhesive sheet with the peeling film L3, L4 was produced in the above-mentioned manner.

＜Production of optical film with release film＞ First, the release film L2 is peeled off from the first adhesive sheet with the release film on both sides, and the exposed surface exposed by this is subjected to plasma treatment. On the other hand, plasma treatment was also performed on both surfaces (first surface and second surface) of a polarizing plate with a thickness of 31 μm. In each plasma treatment, a plasma irradiation device (product name "AP-TO5", manufactured by Sekisui Kogyo Co., Ltd.) was used, and the voltage was set to 160 V, the frequency was set to 10 kHz, and the processing speed was set to 5000 mm/min ( The same applies to the plasma treatment described later). Next, the above-mentioned exposed surface of the first adhesive sheet was bonded to the first surface of the polarizing plate. In this lamination, the 1st adhesive sheet with the release film L1 and the polarizing plate were pressure-bonded by the operation which made the 2 kg roller reciprocate once in the environment of 25 degreeC.

Next, the release film L3 is peeled from the second adhesive sheet with the release films L3 and L4, and the exposed surface exposed by this is subjected to plasma treatment. Next, the exposed surface of the second adhesive sheet was bonded to the second surface of the polarizing plate. In this lamination, the 2nd adhesive sheet with the peeling film L4 and the polarizing plate were pressure-bonded by the operation which made the 2 kg roller reciprocate once in the environment of 25 degreeC. Thereby, a laminated film composed of a laminate of the first adhesive sheet with release film L1 (thickness 50 μm), a polarizing plate, and the second adhesive sheet with release film L4 (thickness 75 μm) was obtained.

Next, the laminated film was punched out into a size of 150 mm×120 mm using a punching machine and a Thomson knife (blanking process step).

Next, contour processing (contour processing step) is carried out in the following manner. First, 50 laminated films punched to the same size were piled up to obtain a laminated body. Specifically, 50 laminated films were stacked so that the release film L1 (first release film) of one of the adjacent laminated films was in contact with the release film L4 (second release film) of the other laminated film. laminated body. This laminate has one surface in the thickness direction (first surface layer) on which the first release film is arranged, and the other surface in the thickness direction (second surface layer) on which the second release film is arranged on the surface. Next, the laminate is held in the thickness direction by a jig for clamping. Next, the pressing force applied by the jig to the laminate in the thickness direction is adjusted so that each adhesive layer protrudes from the end surface of the laminate to a certain extent. In this state, the laminate was cut in the thickness direction within 0.5 mm from the end face of the laminate to re-form the outer peripheral end of the laminate. For cutting, a specific cutting machine and a first rotary blade installed in the machine are used. The rotary knife has a disc portion and a plurality of protruding knives protruding radially from the peripheral end of the disc portion toward the disc. As shown in FIG. 4A and FIG. 4B , the protruding knife 70 has a linear blade 71 (length 6 mm) for cutting the cutting object 80 at the front edge when the rotary knife rotates. In the shape processing step, the rotary blades are rotated relative to the laminate in such a way that each protruding knife 70 cuts into the laminate (cutting object 80) from the first surface side, and the rotation speed of the rotary blade is set to 4500 rpm, set the displacement speed of the rotary knife relative to the laminate to 1000 mm/min, and set the elevation angle (blade angle θ) of the facing blade 71 relative to the surface of the laminate (the first surface layer) before cutting the laminate Set to -5° (Fig. 4B) (the case where the edge angle θ is opened toward the radially outer side of the disk as shown in Fig. 4A is set as a positive edge angle θ, and the edge angle θ is set as shown in Fig. The case where the inner side is open is set as a negative edge angle θ). Then, after the shape processing, the pressurized state of the laminate formed by the jig is released.

The optical film with release film of Example 1 was produced in the above-mentioned manner. The optical film with a release film is sequentially provided with a first release film (release film L1) as a light release film, a first adhesive layer (first adhesive sheet), a polarizing plate as an optical film, and a second release film as an optical film in the thickness direction. The adhesive layer (second adhesive sheet) and the second release film (release film L4) which is a heavy release film have side concave-convex end portions on the entire outer peripheral end. In the concave-convex end portion of the side surface, each edge of the first and second adhesive layers is retreated from the edge of each film in the in-plane direction of the film. In addition, in the optical film with a release film produced as described above, the edges of the first release film, the optical film, and the second release film are at substantially the same position in the in-plane direction of the film. That is, in the side concavo-convex end portion of the optical film with release film, the first relief length d1 from the first edge of the first adhesive layer to the edge of the first release film is substantially equal to the first adhesive layer The distance d1' between the first edge of the second adhesive layer and the edge of the optical film, and the second relief length d2 between the second edge of the second adhesive layer and the edge of the second peeling film are substantially equal to that of the second adhesive layer. The distance d2' between the second edge and the edge of the optical film.

[Embodiments 2-6] Except the following, the optical film with a release film of each of Examples 2-6 was produced in the same manner as the optical film with a release film of Example 1.

Regarding the above-mentioned edge angle θ during contour processing, in Examples 3 and 4, the absolute value is adjusted in a manner that is larger on the negative side than in Example 1, and in Example 2, the absolute value is further adjusted on the negative side than in Example 3, 4 is adjusted in a way that is larger, and in Example 6, the absolute value and the negative side are adjusted in a way that is larger than that of Example 2. Also, in Example 5, the blade angle θ during contour machining was adjusted to change to the positive side compared with Example 1, and the displacement speed of the rotary blade during this machining was adjusted to be slower than Example 1.

[Example 7] The optical film with a release film of Example 7 was produced in the same manner as the optical film with a release film of Example 1 except that a polarizer with a thickness of 80 μm was used instead of a polarizer with a thickness of 31 μm.

[Example 8] The optical film with a release film of Example 7 was produced in the same manner as the optical film with a release film of Example 1 except that a polarizer with a thickness of 100 μm was used instead of a polarizer with a thickness of 31 μm.

[Comparative example 1] The optical film with a release film of Comparative Example 1 was produced in the same manner as the optical film with a release film of Example 1 except that the operation after the punching process was not performed.

[Comparative example 2] Except for the following, the optical film with a release film of Comparative Example 2 was produced in the same manner as the optical film with a release film of Example 1.

Use the 2nd rotary knife instead of the 1st rotary knife. The rotary knife has a disc portion and a plurality of protruding knives protruding radially from the peripheral end of the disc portion toward the disc. In the shape processing step, the rotary knife is rotated relative to the laminated body in such a manner that each protruding knife 70 cuts into the laminated body (cutting object 80) from its second surface side (that is, the laminated body is rotated relative to the rotary knife). The pros and cons of the arrangement are opposite to those in Example 1), and the rotation speed of the rotary knife is set to 4500 rpm, the displacement speed of the rotary knife relative to the laminate is set to 1000 mm/min, and the opposite blade 71 ( The elevation angle (blade angle θ) with respect to the surface of the laminate (the second surface layer) immediately before cutting the laminate was set to +5° (Fig. 4A).

＜Retraction length＞ For each of the optical films with release films (optical films with release films on both sides) in Examples 1 to 8 and Comparative Examples 1 and 2, the first edge of the first adhesive layer of the first adhesive layer was inspected in the following manner. The back-off length d1 and the second back-off length d2 of the second edge of the second adhesive layer.

First, after the first release film is peeled from the optical film with a release film on both sides, the optical film with a release film on one side is attached to a glass substrate through the first adhesive layer exposed by the peeling. Next, the 2nd peeling film was peeled off from the optical film (optical film with adhesive layer attached to both surfaces) on the glass substrate. Specific locations selected from the outer periphery of the optical film with adhesive layers on both sides on the glass substrate were observed with an optical microscope. Specifically, in the thickness direction of the optical film with the adhesive layer on both sides, the optical film with the adhesive layer on both sides was observed and photographed from the side opposite to the glass substrate with an optical microscope. Then, in the captured image, the distance d1' between the first edge of the first adhesive layer and the edge of the optical film, and the distance between the second edge of the second adhesive layer and the end of the optical film The back-off length d2' of the edge is measured. The measurement results are shown in Table 1 in the form of back-off length d1 (μm) and back-off length d2 (μm) (as mentioned above, back-off length d1' is substantially equal to back-off length d1, back-off length d2' is substantially equal to back-off length d2) .

＜Peel initiation force and peel force＞ The force required for the peeling of each peeling film (peeling start force and subsequent peeling force) was examined for each of the optical films with a release film in Examples 1 to 8 and Comparative Examples 1 and 2.

First, a test piece for measurement (about 25 mm on the short side x 150 mm on the long side) is cut out from the optical film with the release film. Specifically, a test piece having a length of about 150 mm and a width of 25 mm was cut out from the side concave-convex end of the optical film with a release film.

Next, the test piece was fixed on a fixing platform of a tensile testing machine (product name "Automatic Stereograph", manufactured by Shimadzu Corporation). Specifically, after peeling and removing one peeling film (first peeling film or second peeling film) from the test piece, the test piece is attached to the platform for fixing through the adhesive layer exposed by the peeling.

Next, stick the adhesive tape for holding to the short side of the concave-convex end side of the other release film (second release film or first release film) located on the exposed surface side of the test piece. The holding tape has a strong adhesive surface, and the holding tape is attached to the release film of the test piece through the strong adhesive surface.

Next, a peeling test in which the peeling film of the adhesive layer in the test piece is peeled from the adhesive layer was implemented with a tensile tester, and the force required for peeling was measured as the peeling strength. In this measurement, the measurement temperature was set to 25°C, the peeling film was peeled off by stretching the holding tape, the peeling angle was set to 180°, the stretching speed was set to 300 mm/min, and the peeling length was set to 100mm. An example of a graph obtained by such a peel test is shown in FIG. 5 . In the graph of FIG. 5 , the horizontal axis represents the peeling length (mm), the vertical axis represents the peeling strength (gf), and Fm represents the maximum value of the peeling strength.

The peeling initiation forces F1, F2 (gf/25 mm) and peeling forces f1, f2 (gf/25 mm) obtained by the above-mentioned peeling test are shown in Table 1 (among them, in Examples 7 and 8 The peel initiation force F1, F2) was not determined. Peeling initiation force F1 is the maximum value of the peeling strength within a peeling length of 20 mm when the first peeling film is peeled from the first adhesive layer. The average value of the peel strength within the peeling initiation force F1 and then stable). Peeling initiation force F2 is the maximum value of the peeling strength within a peeling length of 20 mm when the second peeling film is peeled from the second adhesive layer. The average value of the peel strength within the peeling initiation force F2 and then stable).

<Suppression of peeling of heavy release film when light release film is peeled> Regarding the optical films with release films in Examples 1 to 8 and Comparative Examples 1 and 2, the difficulty of peeling off the heavy release film when peeling off the light release film was examined. Specifically, first, 10 evaluation samples were produced for each optical film with a release film. Next, the light release film of each evaluation sample was peeled off. For the peeling system, a tensile tester (product name "Automatic Stereograph", manufactured by Shimadzu Corporation) was used. In peeling, the peeling angle was set to 180°, and the stretching speed was set to 300 mm/min. Then, when the number of evaluation samples that did not peel off the heavy peeling film and only the light peeling film could be properly peeled off was 10, it was evaluated as "excellent", when the number was 7-9, it was evaluated as "good", and when the number was 0-6 The condition was evaluated as "bad". Table 1 shows the evaluation results.

＜Inhibition of Cracks at the End of Optical Film＞ Regarding the optical films with release films in Examples 1 to 8 and Comparative Examples 1 and 2, the difficulty of generating cracks at the ends of the optical films when the release films were lightly peeled was examined. Specifically, first, evaluation samples were produced for each optical film with a release film. Next, the light peel film of the evaluation sample was manually peeled off. Next, the outer periphery of the optical film (a region 1 mm from the edge) was observed with an optical microscope. Then, when the cracks of 200 μm or more in length were not generated on the outer peripheral portion of the optical film after peeling off the light release film, it was evaluated as “excellent”, and when cracks of 200 μm or more in length were generated, it was rated as “poor”.

＜Adhesion at the end＞ For each of the optical films with release films in Examples 1 to 8 and Comparative Examples 1 and 2, the difficulty of end adhesion was checked. Specifically, first, 10 evaluation samples were produced for each optical film with a release film, and the 10 evaluation samples were stacked to form a film stack (first step). Secondly, press the front end of a cylindrical rod (diameter 10 mm) with an adhesive surface against the optical film with a release film on the top of the film stack from above, then pull the rod upwards, and calculate the following The number of pieces of optical film with release film lifted by the rod (step 2). The test including the first step and the subsequent second step was performed 10 times for each optical film with a release film. In the 10 tests, the number of tests in which only one piece of optical film with a peeling film was raised with the rod was evaluated as "excellent", 6 to 9 cases were evaluated as "good", and the number was 5 or less. The condition was evaluated as "bad". The evaluation results are shown in Table 1.

[Table 1] Table 1 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Comparative example 1 Comparative example 2 Thickness of light release film (μm) 50 50 50 50 50 50 50 50 50 50 Thickness H of the first adhesive layer (μm) 50 50 50 50 50 50 50 50 50 50 Optical film thickness (μm) 31 31 31 31 31 31 80 100 31 31 Thickness of the second adhesive layer (μm) 50 50 50 50 50 50 50 50 50 50 Thickness of heavy release film (μm) 75 75 75 50 75 75 75 75 75 75 1st retraction length d1(μm) 80 130 90 90 20 280 80 80 0 100 2nd retraction length d2(μm) 120 150 150 300 50 350 120 120 0 65 d2－d1(μm) 40 20 60 210 30 70 40 40 0 -35 d1/H 0.8 2.6 1.8 1.8 0.4 5.6 1.6 1.6 0 -0.7 Peeling start force F1(gf/25 mm) 170 30 100 100 350 70 - - 600 80 Peel force f1(gf/25 mm) 2 2 2 2 2 2 2 2 2 2 Peeling start force F2 (gf/25 mm) 220 190 190 180 550 160 - - 950 300 Peeling force f2(gf/25 mm) 4 4 4 14 4 4 4 4 4 4 F1/F2 0.77 0.16 0.53 0.56 0.64 0.44 - - 0.63 0.27 Peeling inhibition of heavy release film excellent excellent excellent excellent excellent excellent excellent excellent bad bad Inhibition of end cracks excellent excellent excellent excellent excellent excellent excellent excellent bad excellent inhibition of adhesion excellent excellent excellent excellent excellent good excellent excellent bad excellent

10: Optical film 11: First surface 12: Second surface 13: Edge 20: Adhesive layer 21: Adhesive surface 22: Edge (first edge) 30: Adhesive layer 31: Adhesive surface 32: Edge (Second edge) 40: light peeling film 40a: free part 42: edge 50: heavy peeling film 52: edge 70: protruding knife 71: blade 80: object to be cut 91: peeling film 91e: edge 92 : Adhesive layer 92e: Edge 93: Optical film 93e: Edge 94: Adhesive layer 94e: Edge 95: Release film 95e: Edge d1: Back-off length d2: Back-off length D: In-plane direction E: Side unevenness End E': End F _m : Maximum value of peel strength M1: First member (first adherend) M2: Second member (second adherend) T: Thickness direction X: Optical film (attached Optical film of release film) Y: Optical film with adhesive layer Z: Film θ: Bevel angle

Fig. 1 is a schematic cross-sectional view of an embodiment of an optical film with a release film of the present invention. Fig. 2 is a partially enlarged cross-sectional model view of the optical film with a release film shown in Fig. 1 . 3A to 3D show an example of the usage method of the optical film with release film of the present invention. Fig. 3A shows the first peeling step of peeling the light release film, Fig. 3B shows the first bonding step of bonding the optical film and the first adherend through the first adhesive layer, and Fig. 3C shows the second peeling step of peeling the heavy release film , FIG. 3D shows the second bonding step of bonding the optical film to the second adherend through the second adhesive layer. 4A and 4B are schematic diagrams for explaining the edge angle of the rotary knife used in the contour processing step in the embodiment and the comparative example. Fig. 5 shows an example of a graph obtained by a peeling test in which the release film on the adhesive layer is peeled off from the adhesive layer. Fig. 6 is a schematic cross-sectional view of a conventional optical film with a release film.

10: Optical film

11:Side 1

12:Side 2

13: Edge

20: Adhesive layer

21: Adhesive surface

22: End edge (first end edge)

30: Adhesive layer

31: Adhesive surface

32: End edge (second end edge)

40: Lightly peel off the film

40a: Free part

42: Edge

50: heavy release film

52: edge

d1: back-off length

d2: back-off length

D: in-plane direction

E: Concave-convex end of the side

T: Thickness direction

Y: Optical film with adhesive layer

Claims (8)

An optical film with a release film comprising an optical film with an adhesive layer, a light release film and a heavy release film, The above-mentioned optical film with an adhesive layer includes: an optical film having a first surface and a second surface opposite to the first surface; a first adhesive layer, which is bonded to the first surface and has a first adhesive surface on the opposite side of the optical film; and A second adhesive layer, which is attached to the second surface and has a second adhesive surface on the opposite side of the optical film; The above-mentioned light release film is arranged on the above-mentioned first adhesive surface, The above-mentioned heavy release film is arranged on the above-mentioned second adhesive surface, The above-mentioned optical film has a thickness of 100 μm or less, The above-mentioned optical film with a release film has side concave-convex end portions, and in the side concave-convex end portions, the first end of the above-mentioned first adhesive layer is The edge and the second edge of the second adhesive layer are retreated from the edges of the optical film, the light release film, and the heavy release film, In the side concave-convex end portion, a first relief length from the first edge to the edge of the light release film is smaller than a second relief length from the second edge to the edge of the heavy release film. The optical film with a release film according to claim 1, wherein the distance between the first edge and the second edge in the in-plane direction is 1 μm or more. The optical film with a release film according to claim 1, wherein the first relief length is 20 μm or more. The optical film with a release film according to claim 1, wherein the ratio of the first relief length to the thickness of the first adhesive layer is not less than 0.4 and not more than 8. The optical film with a release film according to any one of claims 1 to 4, wherein the first peeling starting force used to start peeling the light release film from the first adhesive surface is used to start peeling from the second adhesive surface The second peeling initiation force for peeling off the above-mentioned heavy peeling film is small. The optical film with a peeling film according to claim 5, wherein the ratio of the first peeling initiation force to the second peeling initiation force is 0.8 or less. The optical film with a peeling film according to claim 6, wherein the first peeling initiation force is less than 800 gf/25 mm. The optical film with a peeling film according to claim 6, wherein the second peeling initiation force is 800 gf/25 mm or less.

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