JP2023102976A - laminate - Google Patents

Abstract

To provide a laminate capable of suppressing fracture of a surface treatment film even when a resin film is removed.SOLUTION: A laminate is formed by laminating a surface treatment film and a liquid crystal film. The surface treatment film includes a base material layer, a coating layer provided on a surface of the base material layer and a first end having no coating layer on the surface of the base material layer. The liquid crystal film includes a resin film and a liquid crystal layer, and the liquid crystal layer faces the surface treatment film. The resin film includes a second end having an uneven area with a surface roughness Sa of 0.03 μm or more and 0.60 μm or less. In a cross section of the laminate, the first end and the second end face each other, and a first position of the end of the coating layer in the first end side is located at the same position as a second position of an inner end of the uneven area of the second end or on the inside of the second position.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to a laminate, and more particularly to a method for producing a polarizing plate using the laminate.

As an optical film used in display devices such as liquid crystal display devices and organic EL display devices, a surface treatment film provided with a coating film such as a retardation layer or a hard coat layer by coating a resin composition on the surface of a base layer such as a resin film is known (for example, Patent Documents 1 and 2).

It is known to improve the handleability of the resin film by providing minute unevenness called knurling to the edge of the resin film used for the optical film (for example, Patent Document 3).

JP 2020-54939 A JP 2011-59154 A JP 2014-218016 A

When manufacturing an optical film in which a surface-treated film and a liquid crystal layer are laminated, the surface-treated film may be obtained by laminating the surface-treated film and the liquid crystal layer side of the liquid crystal film in which the liquid crystal layer is formed on the resin film with knurling at the end, and peeling the resin film from this laminate to obtain the optical film. In the laminate, the surface-treated film may be in contact with and attached to the knurled region of the resin film. When the resin film was peeled off from the laminated body having this adhered state, the surface treatment film was broken in some cases.

An object of the present invention is to provide a laminate capable of suppressing breakage of a surface-treated film even when a resin film having uneven regions at the edges is peeled off, and a method for producing a polarizing plate using the same.

[1] A laminate in which a surface-treated film and a liquid crystal film are laminated,
The surface-treated film has a substrate layer, a coating layer provided on the surface of the substrate layer, and a first end portion where the coating layer is not provided on the surface of the substrate layer,
The liquid crystal film has a resin film and a liquid crystal layer, and the liquid crystal layer side faces the surface treatment film,
The resin film has a second end portion having an uneven region with a surface roughness Sa of 0.03 μm or more and 0.60 μm or less,
In the cross section of the laminate, the first end and the second end face each other, and the first position of the end of the coating layer on the first end side is the same as or inside the second position of the inner end of the uneven region of the second end.
[2] The laminate according to [1], wherein the liquid crystal layer covers at least part of the uneven region.
[3] The coated region in which the coating layer is provided on the base layer surface of the surface-treated film has a puncture strength of 1.00 N or less at a temperature of 23° C. and a relative humidity of 55%,
The laminate according to [1] or [2], wherein the substrate layer has a puncture strength of 3.00 N or more at a temperature of 23° C. and a relative humidity of 55%.
[4] The laminate according to any one of [1] to [3], wherein the surface-treated film has a tear strength of 0.5 N or more when the surface-treated film is torn from the first end at a temperature of 23° C. and a relative humidity of 55%.
[5] The laminate according to any one of [1] to [4], wherein a distance L1 between the first position and the second position is 1 mm or more.
[6] The laminate according to any one of [1] to [5], wherein the first end and the second end are provided along a pair of opposite sides of the laminate when viewed from above.
[7] The laminate according to any one of [1] to [6], wherein the uneven region is a knurling portion.
[8] The laminate according to any one of [1] to [7], wherein the substrate layer has a thickness of 20 μm or less.
[9] The laminate according to any one of [1] to [8], wherein the substrate layer is a cyclic olefin resin film.
[10] The laminate according to any one of [1] to [9], wherein the coating layer is a cured product layer of a composition containing an ultraviolet curable resin.
[11] The laminate according to any one of [1] to [10], wherein the resin film is a cellulose resin film.
[12] At a temperature of 23 ° C. and a relative humidity of 55%, 90 or more cross hatches remain on the base layer in a cross hatch test performed by forming 100 cross hatches in the coating layer of the surface treatment film. The laminate according to any one of [1] to [11].
[13] The laminate is a long body,
The laminate according to any one of [1] to [12], wherein the first end and the second end are provided at both ends in the width direction of the laminate.
[14] The laminate according to any one of [1] to [13], further comprising a linear polarizing layer between the surface-treated film and the liquid crystal film.
[15] A method for producing a polarizing plate having a linear polarizing layer and a surface-treated film laminated on one side of the linear polarizing layer,
A method for producing a polarizing plate, comprising the step of peeling the resin film from the laminate according to [14].

According to the laminate of the present invention, breakage of the surface-treated film can be suppressed even when the resin film having uneven regions at the edges is peeled off.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows typically the laminated body which concerns on one Embodiment of this invention. FIG. 4 is a cross-sectional view schematically showing a laminate according to another embodiment of the invention; FIG. 4 is a cross-sectional view schematically showing a layered product according to still another embodiment of the present invention; FIG. 3 is a plan view schematically showing a sample piece used for measuring tear strength.

Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiments. In each drawing, the same reference numerals are assigned to the same members as those previously described, and the description thereof will be omitted. All the drawings below are shown to aid understanding of the present invention, and the size and shape of each component shown in the drawings do not necessarily match the size and shape of the actual component.

[Embodiment 1]
(Laminate)
FIG. 1 is a cross-sectional view schematically showing a laminate according to one embodiment of the present invention. As shown in FIG. 1, the laminate 1 is formed by laminating a surface treatment film 10 and a first liquid crystal film 20 (liquid crystal film).

The surface-treated film 10 has a substrate layer 11, a coating layer 12 provided on the surface of the substrate layer 11, and a first end portion 16 where the coating layer 12 is not provided on the surface of the substrate layer 11. A region in which the coating layer 12 is provided on the surface of the substrate layer 11 of the surface-treated film 10 is a coating region 17 .

The first end 16 may be provided along part or all of at least one of the sides of the surface-treated film 10 in plan view, and may be provided along part or all of two or more sides. The first end portion 16 is preferably provided along a pair of opposite sides of the surface-treated film 10 in plan view. In the laminate 1 shown in FIG. 1 , the first end portions 16 are preferably provided at both ends in the width direction W of the laminate 1 . The width of the first end 16 is usually 5 mm or more, and may be 10 mm or more, and may be, for example, 100 mm or less, 80 mm or less, 50 mm or less, or 40 mm or less. The width of the first end portion 16 is the shortest distance from the end portion of the base material layer 11 to the end portion of the coating layer 12, and can be determined by the method described in Examples below.

The first liquid crystal film 20 has a first resin film 21 (resin film) and a first liquid crystal layer 22 (liquid crystal layer). The first liquid crystal film 20 may be in direct contact with the first resin film 21 and the first liquid crystal layer 22, or may have a first alignment layer between the first resin film 21 and the first liquid crystal layer 22. When the first liquid crystal film 20 has a first alignment layer, the first resin film 21 and the first liquid crystal layer 22 can be in direct contact with the first alignment layer. In the first liquid crystal film 20, the first resin film 21 and the first liquid crystal layer 22 can be separated between the first resin film 21 and the first liquid crystal layer 22 or between the first alignment layer and the first liquid crystal layer 22. The first resin film 21 has a second end portion 26 having an uneven region 25 with a surface roughness Sa of 0.03 μm or more and 0.60 μm or less.

The uneven region 25 of the second end portion 26 may be formed in the entire second end portion 26 or may be formed in a part of the second end portion 26 . The uneven area 25 is preferably formed along the side of the second end 26 . The uneven area 25 can be formed at least on the surface facing the surface treatment film 10 .

The uneven region 25 can be, for example, a knurling portion. The knurling portion is a region in which minute unevenness (knurling) is formed to suppress winding misalignment, deformation, blocking of the first resin film 21, etc. when the first resin film 21 is wound into a roll. The second end portion 26 may be provided along part or all of the sides of the first liquid crystal film 20 in plan view, and may be provided along part or all of two or more sides. The second end portions 26 are preferably provided along a pair of opposite sides of the surface-treated film 10 in a plan view. In the laminate 1 shown in FIG. 1 , it is preferable that they are provided at both ends in the width direction W of the laminate 1 .

The surface roughness Sa of the uneven region 25 is 0.03 μm or more, but may be 0.05 μm or more, 0.10 μm or more, 0.20 μm or more, or 0.60 μm or less, but may be 0.50 μm or less, or 0.40 μm or less. A peak value (surface roughness peak value) that can be obtained together with the surface roughness Sa when measuring the surface roughness Sa of the uneven region 25 may be 0.30 μm or more, 1.00 μm or more, 3.00 μm or more, 15.00 μm or less, 10.00 μm or less, or 8.00 μm or less. The surface roughness Sa and the peak value can be measured by the method described in Examples below. The surface roughness Sa is the "arithmetic mean height", and the surface roughness peak value (also referred to as Sp) is the "maximum peak height".

In the cross section of the first liquid crystal film 20, the edge of the first liquid crystal layer 22 is usually located inside the edge of the first resin film 21, but the first liquid crystal layer 22 may cover the entire surface of the first resin film 21. The inner side is the central side in the plane of the first liquid crystal film 20 . The first liquid crystal layer 22 may cover at least part of the uneven region 25 of the first resin film 21 , may cover the entire uneven region 25 , or may not cover the uneven region 25 .

In the laminate 1, the first liquid crystal film 20 faces the surface treatment film 10 on the first liquid crystal layer 22 side as shown in FIG. The surface-treated film 10 may face the first liquid crystal film 20 on the substrate layer 11 side, or face the first liquid crystal film 20 on the coating layer 12 side, as shown in FIG. The surface treatment film 10 and the first liquid crystal film 20 can be laminated via, for example, the first bonding layer 41 as shown in FIG. Between the surface-treated film 10 and the first liquid crystal film 20, a linear polarization layer, a second liquid crystal layer, a bonding layer other than the first bonding layer, and the like may be provided. Laminates having these layers will be described later in the embodiments.

In the surface-treated film 10 and the first resin film 21 in the laminate 1, the first end 16 and the second end 26 face each other in the cross section of the laminate 1, and the first position 13 of the end of the coating layer 12 on the first end 16 side is the same as or inside the second position 23 of the inner end of the uneven region 25 of the second end 26 (FIG. 1). The inside is the central side of the plane of the surface treatment film 10 , and the inside of the uneven region is the central side of the plane of the first liquid crystal film 20 . The inner end portion of the uneven region 25 refers to the innermost position in the cross section of the laminate 1 among the positions where the formation of the concave portion or the convex portion is started. Therefore, in the cross section of the laminate 1 , the coating layer 12 and the uneven area 25 do not overlap in the lamination direction of the laminate 1 except for the first position 13 and the second position 23 .

Regarding the first end portion 16 and the second end portion 26, in the cross section of the laminate 1, the entire first end portion 16 and the second end portion 26 may face the entire first end portion 16, the second end portion 26 may partially face the entire first end portion 16, the second end portion 26 may face a portion of the first end portion 16, and the second end portion 26 may face a portion of the first end portion 16.

The first end portion 16 and the second end portion 26 may face each other with another layer such as the first liquid crystal layer 22 and the first bonding layer 41 interposed between the first end portion 16 and the uneven region 25 of the second end portion 26 in the cross section of the laminate 1, or may face each other without any other layer interposed therebetween. When the first liquid crystal layer 22 of the first liquid crystal film 20 covers at least part of the uneven region 25, the first liquid crystal layer 22 can exist between the uneven region 25 of the first end 16 and the second end 26 (FIG. 1).

After peeling off the first resin film 21, the laminate 1 is applied to a display device such as a liquid crystal display device and an organic EL display device. At the end of the laminate 1, the surface treatment film 10 and the uneven region 25 of the first resin film 21 included in the first liquid crystal film 20 may be in contact with each other directly or via another layer such as the first liquid crystal layer 22. When the first resin film 21 is peeled off from the laminate 1 in this state, the edge of the surface treatment film 10 adhering to the first resin film 21 is also pulled along with the peeling of the first resin film 21 . At this time, if the coating layer 12 is also formed on the end portion of the surface treatment film, the end portion tends to be brittle due to a decrease in the piercing strength described later, so the surface treatment film may break due to peeling of the first resin film.

On the other hand, in the laminate 1 of the present embodiment, the first position 13 of the coating layer 12 on the first end 16 side of the surface treatment film 10 is the same as or inside the second position 23 of the uneven region 25 of the second end 26 of the first liquid crystal film 20. Therefore, even when the first liquid crystal film 20 and the surface treatment film 10 are attached to each other in contact with each other at the edge of the laminate 1, the first edge 16 where the coating layer 12 is not formed can be attached to the uneven region 25 of the first liquid crystal film 20. The first end portion 16 has a higher puncture strength than the region where the coating layer 12 is formed. As a result, even when the first resin film 21 is peeled off from the laminate 1 in which the first end 16 of the surface treatment film 10 and the second end 26 of the first liquid crystal film 20 are attached, the breakage of the surface treatment film 10 can be suppressed.

As described above, in the laminate 1, the first position 13 of the coating layer 12 on the first end 16 side may be the same as or inside the second position 23 of the uneven region 25 of the second end 26. Therefore, the distance L1 between the first position 13 and the second position 23 in the cross section of the laminate 1 (distance along the surface direction of the laminate) may be 0 mm or more, but is preferably 1 mm or more, may be 2 mm or more, may be 3 mm or more, may be 5 mm or more, and may be, for example, 50 mm or less, may be 30 mm or less, may be 20 mm or less, or may be 10 mm or less. From the viewpoint of sufficiently suppressing breakage of the surface treatment film 10, it is preferable that the distance L1 is large.

In the laminate 1, the distance L2 from the surface of the surface-treated film 10 on the first liquid crystal film 20 side to the surface of the first resin film 21 of the first liquid crystal film 20 on the surface-treated film 10 side (surface other than the uneven region 25) may be 50 μm or less, 30 μm or less, or 20 μm or less, and may be usually 1 μm or more, 5 μm or more, or 10 μm or more. In the laminate 1 having the distance L2 within the above range, the surface treatment film 10 and the first liquid crystal film 20 tend to adhere to each other at the edges of the laminate 1 . Therefore, by setting the first position 13 at the same position as the second position 23 or inside the second position 23 as described above, the breakage of the surface treatment film 10 can be effectively suppressed when the first resin film 21 is peeled off from the laminate 1.

The puncture strength of the coated region 17 of the surface-treated film 10 at a temperature of 23° C. and a relative humidity of 55% may be 1.00 N or less, 0.90 N or less, 0.80 N or less, 0.30 N or more, or 0.40 N or more. The puncture strength of the substrate layer 11 at a temperature of 23° C. and a relative humidity of 55% of the surface-treated film 10 may be 3.00 N or more, 3.30 N or more, 4.00 N or more, or 10.00 N or less. The piercing strength of the base material layer 11 can be considered as the piercing strength of the first end portion 16 of the surface treatment film 10 . The above puncture strength can be measured using a handy compression tester equipped with a needle as described in Examples below.

When the puncture strength of the coating region 17 and the base layer 11 is within the above range, it becomes easier to suppress breakage of the surface treatment film 10 when the first resin film 21 is peeled off from the laminate 1. The piercing strength of the coating region 17 of the surface-treated film 10 and the substrate layer 11 can be adjusted by, for example, the thickness of the coating layer 12, the thickness of the substrate layer 11, the density of the substrate, the type of resin constituting the substrate layer 11, and the degree of crystallinity of the resin.

At a temperature of 23° C. and a relative humidity of 55%, the tear strength when the surface-treated film 10 is torn from the first end 16 is preferably 0.5 N or more, 0.8 N or more, 1.0 N or more, 1.2 N or more, 1.5 N or more, 1.8 N or more, usually 5.0 N or less, 4.5 N or less, or 4.0 N or less.

The tear strength of the surface-treated film 10 is the tear strength when the surface-treated film 10 is torn from the edge of the surface-treated film 10 where the first edge 16 is located as the tear start position, and can be measured by the method described in the examples described later. When the side of the surface-treated film 10 included in the first end portion 16 is linear, the tearing direction is a direction perpendicular to the side. The tearing direction may be rephrased as the direction in which the tear progresses when torn.

When the tear strength of the surface treatment film 10 is within the above range, it becomes easier to suppress breakage of the surface treatment film 10 when peeling the first resin film 21 from the laminate 1 . The tear strength of the surface-treated film 10 can be adjusted by, for example, the thickness of the base layer 11 and the width of the first end 16 (the width of the region where the coating layer 12 is not provided on the surface of the base layer 11).

The width of the first end portion 16 of the surface-treated film 10 is preferably 1 mm or more, may be 5 mm or more, may be 7 mm or more, may be 10 mm or more, and may be, for example, 50 mm or less, or may be 40 mm or less. By setting the width of the first end portion 16 within the above range, it becomes easier to adjust the tear strength of the surface-treated film 10 to the above-described tear strength. The width of the first end portion 16 refers to the average value of the shortest distances from the end of the base layer 11 to the end of the coating layer 12 at a total of three positions, i.e., the central position in the extending direction of the first end portion 16 of the sample taken from the surface-treated film 10 and the position of 1 cm in both directions along the extending direction from the central position (horizontal direction), and can be determined by the method described in the examples described later. When the surface-treated film 10 is a long body, samples are taken from both ends in the length direction of the long body, and the average value of the shortest distances determined by the above procedure for each of the two samples taken is further averaged. When the surface-treated film 10 is a sheet, it is collected at an arbitrary position.

The surface-treated film 10 preferably leaves 90 or more cross-hatches of the coating layer 12 on the base material layer 11 in a cross-hatch test in which 100 cross-hatches are formed in the coating layer 12, more preferably 95 or more, and even more preferably 100. Such a surface-treated film 10 is considered to have excellent adhesion between the substrate layer 11 and the coating layer 12 . Since the surface treatment film 10 having excellent adhesion tends to be brittle in the region where the coating layer 12 is formed, it is considered that the surface treatment film 10 is likely to break when the first resin film 21 is peeled off from the laminate 1. Therefore, in the laminate 1 including the surface-treated film 10 having excellent adhesion between the base material layer 11 and the coating layer 12, as described above, by setting the first position 13 to be the same as the second position 23 or inside the second position 23, it is possible to effectively suppress the breakage of the surface-treated film 10 when the first resin film 21 is peeled off from the laminate 1. The cross-hatch test is performed by cutting 100 cross-hatches of 1 mm square on the surface of the coating layer 12 of the surface treatment film 10 at a temperature of 23 ° C. and a relative humidity of 55%, and peeling off the adhesive tape attached to the cross-hatches.

When the surface-treated film 10 and the first liquid crystal film 20 are laminated via the first bonding layer 41, the position of the end of the first bonding layer 41 at the end of the laminate 1 is preferably at the same position as or inside the end of the first liquid crystal layer 22 of the first liquid crystal film 20 in the cross section of the laminate 1, and preferably at the same position as the end of the surface-treated film 10 or inside the end.

When the first liquid crystal film 20 has a first alignment layer, the position of the end of the first alignment layer at the end of the laminate 1 is preferably at the same position as or inside the end of the first resin film 21 in the cross section of the laminate 1, and preferably at the same position as the end of the first liquid crystal layer 22 or inside the end. The first liquid crystal layer 22 may be provided so as to cover the side surface of the end of the first alignment layer.

The laminate 1 may be a sheet-fed body or a long body that can be continuously transported. In this specification, a long body refers to a laminate having a length of, for example, 30 m or more and 15000 m or less. When the laminate 1 is a long body, the first end 16 and the second end 26 are preferably provided at both ends in the width direction W of the laminate 1 .

The laminate 1 can be produced by laminating the surface-treated film 10 and the first liquid crystal film 20 via, for example, the first bonding layer 41 . The surface-treated film 10 can be obtained by coating the substrate layer 11 with a coating material for forming the coating layer 12 . The first liquid crystal film 20 can be obtained by applying a composition for forming the first liquid crystal layer 22 to the first resin film 21 or the first alignment layer formed on the first resin film 21 .

When the first liquid crystal layer 22 is a retardation layer, a layer obtained by peeling the first resin film 21 from the laminate 1 can be used as a retardation plate. When the first liquid crystal layer 22 is a linear polarizing layer, the laminate 1 obtained by peeling the first resin film 21 can be used as a linear polarizing plate.

When the first resin film 21 is separated from the laminate 1 , the first resin film 21 or the first resin film 21 and the first orientation layer may be separated from the laminate 1 . Alternatively, the laminate 1 may be separated from the first resin film (and the first alignment layer) while the region of the first liquid crystal layer 22 that is not bonded to the first bonding layer 41 is attached to the first resin film 21. Further, in the region where the first end portion 16 and the second end portion 26 of the laminate 1 are opposed to each other, part of the first liquid crystal layer 22 may adhere to the surface treatment film 10 .

[Embodiment 2]
FIG. 2 is a cross-sectional view schematically showing a laminate according to another embodiment of the invention. The laminate 2 of the present embodiment differs from the laminate 1 described in the previous embodiment in that it has a layer other than the first bonding layer 41 between the surface treatment film 10 and the first liquid crystal film 20. This point will be described below. Other than this point, the layered product 2 can be as described for the layered product 1 of the previous embodiment.

In the laminate 2, as shown in FIG. 2, a second bonding layer 42, a linear polarizing layer 30, and a third bonding layer 43 are laminated in order from the surface treatment film 10 side between the surface treatment film 10 and the first liquid crystal film 20. The laminate 2 may have a protective layer on the first liquid crystal film 20 side of the linear polarizing layer 30 . In the laminate 2, the distance L2 from the surface of the surface-treated film 10 on the first liquid crystal film 20 side to the surface of the first resin film 21 of the first liquid crystal film 20 on the surface-treated film 10 side (surface other than the uneven region 25) is preferably within the range described in the previous embodiment.

The position of the end of the second bonding layer 42 at the end of the laminate 2 is preferably at the same position as or inside the end of the surface treatment film 10 in the cross section of the laminate 2. It is preferably at the same position as the end of the linear polarizing layer 30 or inside the end. The position of the end of the third bonding layer 43 at the end of the laminate 2 is preferably at the same position as or inside the end of the linear polarizing layer 30, and is preferably at the same position as or inside the end of the first liquid crystal layer 22. At the edge of the laminate 2, the edge of the linear polarizing layer 30 is preferably at the same position as the edge of the first liquid crystal layer 22 or inside the edge.

The laminate 2 can be manufactured, for example, by laminating the surface-treated film 10 and the linear polarizing layer 30 via the second bonding layer 42 to obtain a linear polarizing plate, and laminating the linear polarizing plate and the first liquid crystal film 20 via the third bonding layer 43.

The first liquid crystal layer 22 may be a retardation layer. For example, when the first liquid crystal layer 22 is a λ / 4 retardation layer, a circularly polarizing plate (polarizing plate) obtained by peeling the first resin film 21 from the laminate 2 can be used. The first liquid crystal layer 22 may be a λ/4 retardation layer with reverse wavelength dispersion.

The manufacturing method of the circularly polarizing plate can include the steps of preparing the laminate 2 and peeling the first resin film 21 from the laminate 2 . By using the laminate 2, it is possible to suppress breakage of the surface treatment film 10 when the first resin film 21 is peeled off.

[Embodiment 3]
FIG. 3 is a cross-sectional view schematically showing a laminate according to still another embodiment of the invention. Since the laminate 3 of the present embodiment differs from the laminates 1 and 2 described in the previous embodiments in the layer structure interposed between the surface treatment film 10 and the first liquid crystal film 20, this point will be described below. Other than this point, the laminate 3 can be made as described in the laminates 1 and 2 of the previous embodiment.

In the laminate 3, as shown in FIG. 3, a second bonding layer 42, a linear polarizing layer 30, a fourth bonding layer 44, a second liquid crystal layer 32, and a fifth bonding layer 45 are laminated in order from the surface treatment film 10 side between the surface treatment film 10 and the first liquid crystal film 20. The laminate 3 may have a second alignment layer on the surface treatment film 10 side or the first liquid crystal film 20 side of the second liquid crystal layer 32 so as to be in direct contact with the second liquid crystal layer 32 . The laminate 3 may have a protective layer on the first liquid crystal film 20 side of the linear polarizing layer 30 . In the laminate 3, the distance L2 from the surface of the surface-treated film 10 on the first liquid crystal film 20 side to the surface of the first resin film 21 of the first liquid crystal film 20 on the surface-treated film 10 side (surface other than the uneven region 25) is preferably within the range described in the previous embodiment.

The position of the end of the fourth bonding layer 44 at the end of the laminate 3 is preferably at the same position as or inside the end of the linear polarizing layer 30 in the cross section of the laminate 3, and preferably at the same position as the end of the second liquid crystal layer 32 or inside the end. The position of the end of the fifth bonding layer 45 at the end of the laminate 3 is preferably at the same position as or inside the end of the second liquid crystal layer 32, and is preferably at the same position as or inside the end of the first liquid crystal layer 22. At the edge of the laminate 3 , the edge of the linear polarizing layer 30 is preferably at the same position as or inside the edge of the first liquid crystal layer 22 .

The laminate 3 can be obtained, for example, by laminating the surface-treated film 10 and the linear polarizing layer 30 via the second bonding layer 42 to obtain a linear polarizing plate, and laminating the second liquid crystal layer 32 and the first liquid crystal film 20 on the linear polarizing plate. The method of laminating the linear polarizing plate, the second liquid crystal layer 32 and the first liquid crystal film 20 includes [a] a method of laminating a liquid crystal layer laminate in which the second liquid crystal layer 32 and the first liquid crystal film 20 are laminated on the linear polarizing plate via a fourth bonding layer 44, and [b] a method of laminating the first liquid crystal film 20 after laminating the second liquid crystal layer 32 on the linear polarizing plate.

The liquid crystal layer laminate used in the above [a] can be produced, for example, as follows. First, a second liquid crystal film is obtained by applying a composition for forming the second liquid crystal layer 32 to the second resin film or the second alignment layer formed on the second resin film. Next, the second liquid crystal layer 32 side of the second liquid crystal film and the first liquid crystal layer 22 side of the first liquid crystal film 20 are laminated via the fifth bonding layer 45, and the second resin film is peeled off. The second resin film is not particularly limited as long as it can support the second alignment layer and/or the second liquid crystal layer 32 and can be separated from the second liquid crystal layer 32 . For the second resin film, for example, one having the structure described for the first resin film 21 can be used.

The method [b] above can be performed, for example, as follows. First, the linear polarizing layer 30 side of the linear polarizing plate and the second liquid crystal layer 32 side of the second liquid crystal film are laminated via the fourth bonding layer 44, and then the second resin film is peeled off. Subsequently, the first liquid crystal layer 22 side of the first liquid crystal film 20 is laminated via the fifth bonding layer 45 on the surface exposed by peeling the second resin film.

Both the first liquid crystal layer 22 and the second liquid crystal layer 32 may be retardation layers. In this case, the combination of the first liquid crystal layer 22 and the second liquid crystal layer 32 includes [i] λ/2 retardation layer and λ/4 retardation layer or [ii] λ/4 retardation layer and positive C retardation layer. The λ/4 retardation layer may have reverse wavelength dispersion. When the first liquid crystal layer 22 and the second liquid crystal layer 32 are the above [i] or [ii], the laminate 3 with the first resin film 21 removed can be used as a circularly polarizing plate (polarizing plate).

The manufacturing method of the circularly polarizing plate can include the steps of preparing the laminate 3 and peeling the first resin film 21 from the laminate 3 . By using the laminate 3, it is possible to suppress breakage of the surface treatment film 10 when the first resin film 21 is peeled off.

Hereinafter, the layers and the like constituting the laminate described above will be described in more detail.
(Base material layer)
The substrate layer 11 contained in the surface treatment film 10 is used to cover the surface of the adherend and support the coating layer 12 . The base material layer 11 is preferably a resin film, preferably a transparent resin film. As the transparent resin film, for example, a film formed using a resin known in the field of optical films, or the like can be used. Examples of transparent resin films include polyolefin films such as polyethylene, polypropylene, and ethylene/propylene copolymers; cyclic olefin resin films made of norbornene-based polymers, etc.; polyester films made of polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; (meth)acrylic resin films made of poly(meth)acrylic acid esters; The transparent resin film is preferably one or more of a cyclic olefin resin film, a polyester film, and a (meth)acrylic resin film, and more preferably a cyclic olefin resin film. "(Meth)acryl" represents at least one of acryl and methacryl. The same applies to "(meth)acrylate" and the like.

The thickness of the base material layer 11 is preferably 20 μm or less, may be less than 20 μm, may be 18 μm or less, may be 15 μm or less, may be 13 μm or less, is usually 1 μm or more, and may be 5 μm or more.

(Coating layer)
The coating layer 12 included in the surface-treated film 10 can be a layer for imparting to the surface-treated film 10 at least one or more specific functions selected from hard coat properties, antiglare properties, antireflection properties, antistatic properties, antifouling properties, and the like. The coating layer 12 includes a hard coat layer, an antiglare layer, an antireflection layer, an antistatic layer, an antifouling layer, and the like.

The coating layer 12 can be formed by coating the substrate layer 11 with a coating material for forming the coating layer 12 . The coating material includes a composition containing a curable compound; a composition containing a resin other than the curable compound, and the like. The coating material may contain fillers such as organic fine particles or inorganic fine particles, antistatic agents, antifouling agents, colorants, ultraviolet absorbers, antioxidants, light stabilizers, flame retardants, viscosity modifiers, cross-linking agents, coupling agents, leveling agents, antifoaming agents, solvents, and the like, in addition to the above-described curable compounds and resins, in order to form the coating layer 12 and/or the functions of the coating layer 12 appropriately.

Examples of the curable compound contained in the composition containing a curable compound include active energy ray-curable resins such as ultraviolet-curable resins and electron beam-curable resins; thermosetting resins; monomers having polymerizable groups such as (meth)acryloyl groups and vinyl groups; oligomers having polymerizable groups. Examples of resins other than curable compounds include thermoplastic resins.

The coating layer 12 is preferably a cured layer of a composition containing an active energy ray-curable resin, more preferably a cured layer of a composition containing an ultraviolet-curable resin. The composition containing an ultraviolet curable resin is preferably an acrylic resin composition containing a (meth)acrylate monomer and/or a (meth)acrylic resin. Examples of (meth)acrylate monomers and/or (meth)acrylic resins include polyfunctional (meth)acrylates, polyfunctional urethanized (meth)acrylates, polyol (meth)acrylates, and optionally curable mixtures containing (meth)acrylic polymers having alkyl groups containing two or more hydroxyl groups.

Examples of polyfunctional (meth)acrylates include trimethylolpropane di- or tri-(meth)acrylates, pentaerythritol tri- or tetra-(meth)acrylates, and polyfunctional urethanized (meth)acrylates which are reaction products of (meth)acrylates and diisocyanates having at least one hydroxyl group in the molecule. These polyfunctional (meth)acrylates may be used alone or in combination of two or more.

Polyfunctional urethane-modified (meth)acrylates are produced using, for example, (meth)acrylic acid and/or (meth)acrylic acid esters, polyols, and diisocyanates. Specifically, a polyfunctional urethanized (meth)acrylate can be produced by preparing a hydroxy (meth)acrylate having at least one hydroxyl group in the molecule from (meth)acrylic acid and/or a (meth)acrylic acid ester and a polyol and reacting it with a diisocyanate. The polyfunctional urethane-modified (meth)acrylate produced in this manner functions as the UV-curable resin described above. In the production thereof, (meth)acrylic acid and/or (meth)acrylic acid ester may be used alone or in combination of two or more. Polyols and diisocyanates may be used either alone or in combination of two or more.

As the (meth)acrylic ester used for forming the polyfunctional urethane-modified (meth)acrylate, a linear or cyclic alkyl ester of (meth)acrylic acid can be used, and specific examples thereof include alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, and butyl (meth)acrylate; and cycloalkyl (meth)acrylates such as cyclohexyl (meth)acrylate.

The polyol used in forming the polyfunctional urethane-modified (meth)acrylate is a compound having at least two hydroxyl groups in the molecule, and specific examples include ethylene glycol, propylene glycol, 1,3-propanediol, diethylene glycol, dipropylene glycol, neopentyl glycol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, 1,9-nonanediol, 1,10-decanediol, and 2,2,4-trimethyl. -1,3-pentanediol, 3-methyl-1,5-pentanediol, neopentyl glycol ester of hydroxypivalic acid, cyclohexanedimethylol, 1,4-cyclohexanediol, spiroglycol, tricyclodecanedimethylol, hydrogenated bisphenol A, ethylene oxide-added bisphenol A, propylene oxide-added bisphenol A, trimethylolethane, trimethylolpropane, glycerin, 3-methylpentane-1,3,5-triol, pentaerythritol , dipentaerythritol, tripentaerythritol, glucoses, and the like.

The diisocyanate used in forming the polyfunctional urethanized (meth)acrylate is a compound having two isocyanato groups (-NCO) in the molecule, and various aromatic, aliphatic or alicyclic diisocyanates can be used. Specific examples include tetramethylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, 2,4-tolylene diisocyanate, 4,4'-diphenyl diisocyanate, 1,5-naphthalene diisocyanate, 3,3'- Examples include dimethyl-4,4'-diphenyl diisocyanate, xylene diisocyanate, trimethylhexamethylene diisocyanate, 4,4'-diphenylmethane diisocyanate, and nucleus-hydrogenated diisocyanates having an aromatic ring among these.

A (meth)acrylic polymer having an alkyl group containing two or more hydroxyl groups has an alkyl group containing two or more hydroxyl groups in one structural unit, and specific examples thereof include a polymer containing 2,3-dihydroxypropyl (meth)acrylate as a structural unit, and a polymer containing 2,3-dihydroxypropyl (meth)acrylate and 2-hydroxyethyl (meth)acrylate as structural units.

A composition containing a curable compound can contain a polymerization initiator in addition to the curable compound. Examples of the polymerization initiator include photopolymerization initiators and radical polymerization initiators, and known polymerization initiators can be used.

When the coating layer 12 is a hard coat layer, the coating layer 12 has a function of improving the surface hardness of the base material layer 11, and can improve the scratch resistance of the surface. The hard coat layer preferably exhibits a value of 8B or harder in a pencil hardness test (measured by placing the surface-treated film on a glass plate) defined in JIS K 5600-5-4:1999 "General test methods for paint-Part 5: Mechanical properties of coating film-Section 4: Scratch hardness (pencil method)", and may be 5B or harder. The coating layer 12 is preferably a hard coat layer.

When the coating layer 12 is an antiglare layer, the coating layer 12 can have functions such as improving visibility, suppressing reflection of external light, and reducing moire (interference fringes). The antiglare layer can have a fine uneven shape on the surface. The fine irregularities can be formed by adding a filler to the antiglare layer, or by finely embossing the surface.

When the coating layer 12 is an antireflection layer, the coating layer 12 can have a function of suppressing reflection of external light. The antireflection layer can be a layer having a refractive index smaller than that of the substrate layer 11, and may contain fine particles, for example.

When the coating layer 12 is an antistatic layer, the coating layer 12 can have a function of suppressing the generation of static electricity. The antistatic layer can contain an antistatic agent (conductive material).

When the coating layer 12 is an antifouling layer, the coating layer 12 can impart functions such as water repellency, oil repellency, sweat resistance, and antifouling properties to the surface-treated film 10 . The antifouling layer can contain antifouling agents such as fluorine-containing organic compounds such as fluorocarbons, perfluorosilanes, and polymeric compounds thereof.

The thickness of the coating layer 12 may be, for example, 1 nm or more, 10 nm or more, 50 nm or more, 500 nm or more, 1 μm or more, 15 μm or less, 10 μm or less, or 5 μm or less.

(First liquid crystal layer, second liquid crystal layer)
The first liquid crystal layer 22 included in the first liquid crystal film 20 and the second liquid crystal layer 32 included in the second liquid crystal film (hereinafter, sometimes collectively referred to as "liquid crystal layer") are layers in which liquid crystal compounds are oriented, and are preferably cured layers of polymerizable liquid crystal compounds.

When the liquid crystal layer is a cured product layer of a polymerizable liquid crystal compound, a known polymerizable liquid crystal compound can be used as the polymerizable liquid crystal compound. A polymerizable liquid crystal compound is a compound having at least one polymerizable group and having liquid crystallinity.

The type of polymerizable liquid crystal compound is not particularly limited, and rod-like liquid crystal compounds, discotic liquid crystal compounds, and mixtures thereof can be used. A cured product layer formed by polymerizing a polymerizable liquid crystal compound develops retardation by curing in a state in which the polymerizable liquid crystal compound is oriented in a suitable direction. When the rod-like polymerizable liquid crystal compound is aligned horizontally or vertically with respect to the planar direction of the laminate, the optical axis of the polymerizable liquid crystal compound coincides with the long axis direction of the polymerizable liquid crystal compound. When the discotic polymerizable liquid crystal compound is oriented, the optical axis of the polymerizable liquid crystal compound exists in a direction orthogonal to the discotic surface of the polymerizable liquid crystal compound. As the rod-like polymerizable liquid crystal compound, for example, those described in JP-A-11-513019 (claim 1 etc.) can be preferably used. As the discotic polymerizable liquid crystal compound, those described in JP-A-2007-108732 (paragraphs [0020] to [0067], etc.) and JP-A-2010-244038 (paragraphs [0013] to [0108], etc.) can be preferably used.

The polymerizable group possessed by the polymerizable liquid crystal compound means a group involved in a polymerization reaction, and is preferably a photopolymerizable group. A photopolymerizable group is a group that can participate in a polymerization reaction by an active radical generated from a photopolymerization initiator, an acid, or the like. Examples of the polymerizable group include vinyl group, vinyloxy group, 1-chlorovinyl group, isopropenyl group, 4-vinylphenyl group, (meth)acryloyloxy group, oxiranyl group, oxetanyl group, styryl group and allyl group. Among them, a (meth)acryloyloxy group, a vinyloxy group, an oxiranyl group and an oxetanyl group are preferred, and an acryloyloxy group is more preferred. The liquid crystallinity of the polymerizable liquid crystal compound may be either thermotropic liquid crystal or lyotropic liquid crystal, and thermotropic liquid crystal may be classified into nematic liquid crystal or smectic liquid crystal according to the degree of order. When two or more types of polymerizable liquid crystal compounds are used in combination to form a cured product layer of the polymerizable liquid crystal compound, at least one type preferably has two or more polymerizable groups in the molecule.

The cured product layer can be formed by applying a composition for forming a liquid crystal layer containing a polymerizable liquid crystal compound and a solvent, and optionally various additives, onto an alignment layer described later to form a coating film, and solidifying (curing) the coating film to form a cured product layer of a polymerizable liquid crystal compound. Alternatively, the composition may be applied on the first resin film or the second resin film to form a coating film, and the coating film may be stretched together with the first resin film or the second resin film to form a cured product layer. The composition may contain a polymerization initiator, a reactive additive, a leveling agent, a polymerization inhibitor, etc., in addition to the polymerizable liquid crystal compound and solvent described above. As the polymerizable liquid crystal compound, solvent, polymerization initiator, reactive additive, leveling agent, polymerization inhibitor, etc., known ones can be appropriately used.

The liquid crystal layer may be a retardation layer or a linear polarizing layer. When the liquid crystal layer is a linearly polarizing layer, the composition for forming the liquid crystal layer may contain a dichroic dye or may contain a dichroic dye having liquid crystallinity.

(First alignment layer, second alignment layer)
The first alignment layer contained in the first liquid crystal film 20 and the second alignment layer contained in the second liquid crystal film (hereinafter, both may be collectively referred to as "alignment layers") have an alignment control force that aligns a liquid crystal compound such as a polymerizable liquid crystal compound in a desired direction. The alignment layer may be a vertical alignment layer in which the molecular axis of the liquid crystal compound is vertically aligned with respect to the planar direction of the laminate, a horizontal alignment layer in which the molecular axis of the liquid crystal compound is horizontally aligned with respect to the planar directions of the first liquid crystal film and the second liquid crystal film, or an inclined alignment layer in which the molecular axis of the liquid crystal compound is tilted with respect to the planar directions of the first liquid crystal film and the second liquid crystal film.

The alignment layer preferably has solvent resistance that does not dissolve when a composition for forming a liquid crystal layer containing a liquid crystal compound such as a polymerizable liquid crystal compound is applied, and has heat resistance to heat treatment for removing the solvent and aligning the liquid crystal compound. Examples of the alignment layer include an alignment polymer layer formed of an alignment polymer, a photo-alignment polymer layer formed of a photo-alignment polymer, and a groove alignment layer having an uneven pattern or a plurality of grooves on the layer surface.

(First resin film, second resin film)
The first resin film 21 included in the first liquid crystal film 20 and the second resin film included in the second liquid crystal film (hereinafter, both may be collectively referred to as "resin film") can be made of a film made of a resin material. Among these, a cellulose resin film such as a triacetyl cellulose film is preferable. Although the thickness of the resin film is not particularly limited, it is generally preferably 1 to 300 μm or less, more preferably 20 to 200 μm, and even more preferably 30 to 120 μm from the viewpoint of workability such as strength and handleability.

The resin film can have uneven areas. The cross-sectional shape of the recesses and protrusions of the uneven region is not particularly limited, and may be one or more selected from trapezoid, truncated cone, prism trapezoid, cylinder, prism, cone, pyramid, irregular shape, and the like. The uneven area can be formed by subjecting a film having no uneven area formed thereon to embossing, laser processing, or the like.

(linear polarizing plate)
The linear polarizing plate has the surface-treated film 10 and the linear polarizing layer 30 and may further have a second bonding layer 42 for bonding the surface-treated film 10 and the linear polarizing layer 30 together. The linear polarizing plate may further have a protective layer on the side of the linear polarizing layer 30 opposite to the surface treatment film 10 side. The linear polarizing layer 30 and the protective layer may be laminated so as to be in direct contact with each other, or may be laminated via a bonding layer.

(linear polarizing layer)
The linearly polarizing layer has the property of transmitting linearly polarized light having a vibration plane perpendicular to the absorption axis when non-polarized light is incident thereon. The linear polarizing layer may be a polyvinyl alcohol-based resin film (hereinafter sometimes referred to as "PVA-based film") in which iodine is adsorbed and oriented, or may be a film including a liquid crystalline linear polarizing layer formed by applying a composition containing a compound having absorption anisotropy and liquid crystallinity to a base film. The compound having absorption anisotropy and liquid crystallinity may be a mixture of a dye having absorption anisotropy and a compound having liquid crystallinity, or may be a dye having absorption anisotropy and liquid crystallinity.

The linear polarizing layer, which is a PVA-based film, includes, for example, a PVA-based film such as a polyvinyl alcohol film, a partially formalized polyvinyl alcohol film, and a partially saponified ethylene/vinyl acetate copolymer film, which is dyed with iodine and stretched. If necessary, the PVA-based film having iodine adsorbed and oriented by the dyeing treatment may be treated with an aqueous boric acid solution, followed by a washing step of washing off the aqueous boric acid solution. A known method can be adopted for each step.

A polyvinyl alcohol-based resin (hereinafter sometimes referred to as "PVA-based resin") can be produced by saponifying a polyvinyl acetate-based resin. The polyvinyl acetate-based resin may be polyvinyl acetate, which is a homopolymer of vinyl acetate, or may be a copolymer of vinyl acetate and another monomer that can be copolymerized with vinyl acetate. Other monomers copolymerizable with vinyl acetate include, for example, unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and acrylamides having an ammonium group.

The saponification degree of the PVA-based resin is usually about 85 to 100 mol %, preferably 98 mol % or more. The PVA-based resin may be modified, and for example, polyvinyl formal or polyvinyl acetal modified with aldehydes may be used. The average degree of polymerization of the PVA-based resin is usually about 1,000 to 10,000, preferably about 1,500 to 5,000. The degree of saponification and average degree of polymerization of the PVA-based resin can be determined according to JIS K 6726 (1994). If the average degree of polymerization is less than 1,000, it is difficult to obtain desirable polarizing performance, and if it exceeds 10,000, film workability may be poor.

A method for producing a linearly polarizing layer that is a PVA-based film may include a step of preparing a base film, applying a solution of a resin such as a PVA-based resin on the base film, and performing drying or the like to remove the solvent to form a resin layer on the base film. A primer layer can be formed in advance on the surface of the substrate film on which the resin layer is formed. As the base film, a film using a resin material described as a thermoplastic resin used for forming a protective film as a protective layer to be described later can be used. Examples of the material for the primer layer include a resin obtained by cross-linking the hydrophilic resin used for the linear polarizing layer.

Next, the amount of solvent such as moisture in the resin layer is adjusted as necessary, and then the base film and resin layer are uniaxially stretched, and then the resin layer is dyed with iodine to adsorb and align iodine on the resin layer. Next, if necessary, the resin layer in which iodine is adsorbed and oriented is treated with an aqueous boric acid solution, followed by a washing step of washing off the aqueous boric acid solution. As a result, a resin layer in which iodine is adsorbed and oriented, that is, a PVA-based film to be a linear polarizing layer is produced. A known method can be adopted for each step.

A linearly polarizing layer produced by a production method using a base film can be obtained by laminating a protective layer and then peeling off the base film.

The thickness of the linear polarizing layer, which is a PVA-based film, is preferably 1 μm or more, may be 2 μm or more, may be 5 μm or more, is preferably 30 μm or less, more preferably 15 μm or less, may be 10 μm or less, and may be 8 μm or less.

A film containing a liquid crystalline linear polarizing layer is obtained by applying a composition containing a dye having liquid crystallinity and absorption anisotropy, or a composition containing a dye having absorption anisotropy and a polymerizable liquid crystal to a base film. The liquid crystalline linear polarizing layer may be a cured product of a polymerizable liquid crystal compound and may contain an orientation layer. The film containing the liquid crystalline linear polarizing layer may be a liquid crystalline linear polarizing layer or may have a laminated structure of a liquid crystalline linear polarizing layer and a substrate film. Examples of the base film include a film using a resin material described as a thermoplastic resin used for forming a protective film as a protective layer to be described later. Films containing a liquid crystalline linear polarizing layer include, for example, polarizing layers described in JP-A-2013-33249.

The total thickness of the base film and the linearly polarizing layer formed as described above is preferably as small as possible, but if it is too small, the strength tends to decrease and the workability tends to be poor.

(protective layer)
The protective layer includes, for example, a protective film that is a film formed from a thermoplastic resin having excellent transparency, mechanical strength, thermal stability, moisture barrier properties, isotropy, stretchability, etc.; solvent resistance, transparency, mechanical strength, thermal stability, shielding properties, an overcoat layer formed from a composition having excellent isotropy, etc., and the like. The protective film is preferably laminated on the linearly polarizing layer via the bonding layer, and the overcoat layer is preferably laminated so as to be in direct contact with the linearly polarizing layer.

Polyamide resins such as nylon and aromatic polyamides; Polyimide resins; Polyolefin resins such as polyethylene, polypropylene, and ethylene/propylene copolymers; Vinyl alcohol resins, as well as mixtures thereof, may be mentioned. The thickness of the protective film is preferably 3 μm or more, more preferably 5 μm or more, and preferably 50 μm or less, more preferably 30 μm or less.

The overcoat layer can be formed, for example, by applying a material (composition) for forming the overcoat layer on the linear polarizing layer. Materials constituting the overcoat layer include, for example, photocurable resins, water-soluble polymers, and the like, and (meth)acrylic resins, polyvinyl alcohol-based resins, polyamide epoxy resins, and the like can be used. The thickness of the overcoat layer can be, for example, 0.1 μm or more and 10 μm or less.

(First bonding layer, second bonding layer, third bonding layer, fourth bonding layer, fifth bonding layer, bonding layer)
The first lamination layer to the fifth lamination layer and the lamination layer (hereinafter sometimes collectively referred to as "lamination layer") are pressure-sensitive adhesive layers or adhesive layers.

The pressure-sensitive adhesive layer is a pressure-sensitive adhesive layer formed using a pressure-sensitive adhesive composition. The pressure-sensitive adhesive composition or the reaction product of the pressure-sensitive adhesive composition develops adhesiveness by sticking itself to an adherend, and is called a pressure-sensitive adhesive. Moreover, the adhesive layer formed using the active-energy-ray-curable adhesive composition mentioned later can adjust a crosslinking degree and adhesive strength by irradiating an active-energy-ray.

As the pressure-sensitive adhesive composition, any known pressure-sensitive adhesive having excellent optical transparency can be used without particular limitation. For example, a pressure-sensitive adhesive composition containing a base polymer such as an acrylic polymer, a urethane polymer, a silicone polymer, or polyvinyl ether can be used. The adhesive composition may also be an active energy ray-curable adhesive composition, a heat-curable adhesive composition, or the like. Among these, a pressure-sensitive adhesive composition using an acrylic resin as a base polymer, which is excellent in transparency, adhesive strength, removability (reworkability), weather resistance, heat resistance, etc., is preferable. The pressure-sensitive adhesive layer preferably comprises a reaction product of a pressure-sensitive adhesive composition containing a (meth)acrylic resin, a cross-linking agent and a silane compound, and may contain other components.

The active energy ray-curable pressure-sensitive adhesive composition can form a harder pressure-sensitive adhesive layer by blending the above-described pressure-sensitive adhesive composition with an ultraviolet-curable compound such as a polyfunctional acrylate and irradiating the layer formed by coating with ultraviolet rays to cure it. The active energy ray-curable pressure-sensitive adhesive composition has the property of being cured by being irradiated with energy rays such as ultraviolet rays and electron beams. Since the active energy ray-curable pressure-sensitive adhesive composition has adhesiveness even before energy ray irradiation, it adheres to an adherend and is cured by energy ray irradiation to adjust the adhesive strength.

The pressure-sensitive adhesive composition and the active energy ray-curable pressure-sensitive adhesive composition may optionally contain additives such as antioxidants, tackifiers, thermoplastic resins, fillers, flow modifiers, plasticizers, antifoaming agents, antistatic agents, and solvents.

The adhesive layer can be formed by curing the curable component in the adhesive composition. Examples of the adhesive composition for forming the adhesive layer include adhesives other than pressure-sensitive adhesives (adhesives), such as water-based adhesives and active energy ray-curable adhesives.

Examples of water-based adhesives include adhesives obtained by dissolving or dispersing polyvinyl alcohol resin in water. The method of drying when a water-based adhesive is used is not particularly limited. For example, a method of drying using a hot air dryer or an infrared ray dryer can be employed.

Active energy ray-curable adhesives include, for example, solvent-free active energy ray-curable adhesives containing curable compounds that are cured by irradiation with active energy rays such as ultraviolet rays, visible light, electron beams, and X-rays. Adhesion between layers can be improved by using a non-solvent active energy ray-curable adhesive.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to these examples.

[Examples 1 and 2, Comparative Example 1]
(Preparation of surface treatment film)
A cyclic olefin resin film (hereinafter sometimes referred to as “COP film”) having a thickness of 13 μm was prepared as a substrate layer. An acrylic resin composition containing an ultraviolet curable resin was gravure-coated on one side of the COP film so that a first end portion was formed along a pair of opposing sides (both ends in the width direction) to form a coating film. After the coating film was dried, it was irradiated with ultraviolet rays to form a coating layer as a hard coat layer on the surface of the substrate layer, thereby obtaining a surface-treated film.

The COP film side of a sample taken from the surface-treated film was pasted to a glass plate, and the shortest distance between the end of the COP film and the coating layer was determined at a total of three positions: the center position in the extending direction of the end of the COP film (the end where the coating layer is not formed) and the position 1 cm in the left-right direction (both directions along the extending direction) from this center position. The width of the first end, which is the distance, was determined. The shortest distance was determined by acquiring a thickness plot while moving from the edge of the COP film of the sample toward the coating layer using a dual-mode 3D confocal/interferometry system PLμ2300 (manufactured by Sensoso Japan Co., Ltd.) (lens: 20x (EPI 20x)). Table 1 shows the determined values of the width of the first end.

For the area of the surface treatment film where the coating layer was formed, the puncture strength and tear strength were measured and a crosshatch test was performed according to the procedure described later. Table 1 shows the results.

(Preparation of laminate)
The substrate layer side of the surface-treated film obtained above and a linear polarizing layer in which iodine was adsorbed and oriented in a polyvinyl alcohol-based resin were laminated via an adhesive layer to obtain a linear polarizing plate.

As the first resin film, a triacetyl cellulose film (hereinafter sometimes referred to as "first TAC film") having uneven regions on both ends in the width direction was used, and a first liquid crystal film was prepared by laminating a first alignment layer and a first liquid crystal layer, which is a cured product layer of a polymerizable liquid crystal compound, in this order on one side of the first TAC film. The first liquid crystal layer partially covered the uneven region. The surface roughness Sa of the uneven region of the first TAC film used for the first liquid crystal film was measured by the procedure described later. Table 1 shows the results.

A second liquid crystal film was prepared by using a triacetyl cellulose film (hereinafter sometimes referred to as a "second TAC film") as the second resin film, and laminating a second alignment layer and a second liquid crystal layer, which is a cured product layer of a polymerizable liquid crystal compound, in this order on one side of the second TAC film.

The first liquid crystal layer side of the first liquid crystal film and the second liquid crystal layer side of the second liquid crystal film were laminated via an adhesive layer to obtain a liquid crystal layer laminate with the second TAC film. The layer structure of the liquid crystal layer laminate with the second TAC film was first TAC film/first alignment layer/first liquid crystal layer/adhesive layer/second liquid crystal layer/second alignment layer/second TAC film.

On the surface exposed by peeling the second TAC film from the liquid crystal layer laminate with the second TAC film, the linear polarizing layer side of the linear polarizing plate obtained above was bonded via the adhesive layer of the ultraviolet curable adhesive to obtain a laminate. The distance L2 from the surface of the surface treatment film on the first liquid crystal film side to the surface of the first TAC film of the first liquid crystal film on the surface treatment film side was about 15 μm.

In Examples 1 and 2, the laminate was produced so that, in its cross section, the position (first position) of the end of the coating layer of the surface treatment film was located inside the position (second position) of the inner end of the uneven region of the first TAC film by the length of the distance L1 shown in Table 1. Therefore, in the laminates of Examples 1 and 2, the first position was inside the second position in the cross section.

In Comparative Example 1, the end position (first position) of the coating layer of the surface treatment film was 5 mm outside the position (second position) of the inner end of the uneven region of the first TAC film. Therefore, in the laminate of Comparative Example 1, the first position was on the uneven region in its cross section.

A peeling test was performed to peel the first TAC film from the laminate, and the presence or absence of breakage of the surface treatment film was confirmed. Table 1 shows the results.

[Reference Example 1]
A laminate was produced in the same manner as in Example 1, except that a substrate layer having no coating layer was used instead of the surface-treated film. A peeling test was performed to peel the first TAC film from the laminate, and the presence or absence of breakage of the surface treatment film was confirmed. Table 1 shows the results. In addition, the puncture strength and tear strength of the base material layer were measured according to the procedure described later. This piercing strength can be considered as the piercing strength at the first end of the base material layer used in Examples 1 and 2 and Comparative Example 1. Table 1 shows the results.

[Measurement of puncture strength]
The puncture strength was measured using a handy compression tester (KES-G5, manufactured by Kato Tech Co., Ltd.) equipped with a needle having a tip diameter (spherical diameter) of 1 mm and a tip curvature radius of 0.5R. Using two jigs having a circular hole (11 mm in diameter) in the center of this testing machine, the surface-treated film or base material layer was sandwiched and fixed. As for the surface-treated film, the region where the coating layer was formed was sandwiched between jigs so that the coating layer faced upward. Next, the needle of the testing machine was lowered vertically against the surface treatment film fixed to the jig so that the needle passed through the hole of the jig, and the strength when the surface treatment film was torn was measured as the puncture strength. The measurement was carried out at a temperature of 23° C. and a relative humidity of 55%, with a puncture speed of 0.33 cm/sec, a load cell of the needle pressurizer of 1 kgf (9.8 N), and SENS: 1 (upper limit load of 100 gf (0.98 N)).

[Measurement of tear strength]
FIG. 4 is a plan view schematically showing a sample piece used for measuring tear strength. At the first end 16 of the surface-treated film, a rectangular sample piece 81 was cut out so as to include the first end 16 of the surface-treated film and the coating region 17 adjacent to the first end 16, and to have a size of 50 mm in the extending direction of the side where the first end 16 of the surface-treated film was located and 70 mm in the direction orthogonal to the side (FIG. 4). Two lead tapes (Piolan cloth curing tape green, 50 mm × 25 mm, Y-09-GR, manufactured by Diatex) 85, 85 were attached to one surface of the sample piece 81 so as to straddle the side 83 constituting the side on which the first end 16 of the surface treatment film was located among the sides of the sample piece 81, the first end 16, and the coating area 17 (hereinafter, the side 83 to which the lead tape was attached is referred to as the "attachment side 83". Yes.). Each lead tape 85 had a length of 50 mm and a width of 20 mm, and was attached to the sample piece 81 so that a gap of 1 mm was formed between the two lead tapes 85, 85 at the center of the attachment side 83 of the sample piece 81, the width direction of the lead tape 85 was parallel to the attachment side 83, and a 10 mm length range from one end was placed on the sample piece 81. Two lead tapes were also attached to the other surface of the sample piece 31 so as to overlap the lead tapes 85 and 85 attached to one surface of the sample piece 81 . As a result, as shown in FIG. 4, two sets of lead tape groups in which two lead tapes (the lead tapes attached to both sides of the sample piece 81) overlap each other in the plan view of the sample piece 81 were attached to the attachment side 83 of the sample piece 81 with an interval (gap) of 1 mm.

Of the longitudinal ends of the lead tape 85 attached to the sample piece 81, the ends opposite to the side attached to the sample piece 81 were fixed to the upper and lower chucks of an autograph ("AGS-50NX" manufactured by Shimadzu Corporation). After that, a 180° tensile test is performed by pulling at a speed of 300 mm/min in opposite directions with respect to the plane of the sample piece 81 (vertical direction with respect to the plane of the sample piece 81) so that one of the two sets of lead tapes is on one side with respect to the plane of the sample piece 81 and the other of the two sets of lead tapes is on the other side with respect to the plane of the sample piece 81, and the first end 16 of the sample piece 81 is torn. Peak values (force magnitudes) were measured. The measurement was performed under conditions of a temperature of 23° C. and a relative humidity of 55%. This measurement was performed 5 times, and the average value of the magnitude of the measured force was taken as the tear strength.

[Cross hatch test]
100 (10×10) cross hatches of 1 mm square were cut into the coating layer surface of the surface treatment film so that the coating layer penetrated. An adhesive tape having a width of 24 mm (adhesive cellophane tape CT405AP-24, manufactured by Nichiban Co., Ltd.) was attached to the crosshatch, and then the adhesive tape was peeled off in a direction of 45° to the crosshatch surface. After peeling off the adhesive tape, the number of cross hatches remaining on the substrate layer was counted. The crosshatch test was performed under conditions of a temperature of 23°C and a relative humidity of 55%.

[Measurement of surface roughness Sa]
The surface roughness Sa of the edge of the first resin film used for the first liquid crystal film was measured using a white interferometer VertScan (registered trademark) (manufacturer: Ryoka Systems Co., Ltd., distributor: Hitachi High-Tech Science Co., Ltd., using a 2.5x lens). From the edge of the first resin film toward the central side of the plane of the first liquid crystal film, a stitching measurement with a field of view of 4×10 (total observation area of 17171.306 μm×5237.490 μm) was performed to measure the surface roughness Sa. Along with this measurement, the peak value Sp (surface roughness peak value Sp) obtained by the measurement with the white light interferometer was also obtained. The surface roughness Sa is the "arithmetic mean height", and the surface roughness peak value Sp is the "maximum peak height".

1,2,3 Laminate 10 Surface treatment film 11 Base layer 12 Coating layer 13 First position 16 First end 17 Coating region 20 First liquid crystal film (liquid crystal film) 21 First resin film (resin film) 22 First liquid crystal layer (liquid crystal layer) 23 Second position 25 Concavo-convex region 26 Second end 30 Polarizing layer 32 Second liquid crystal layer 41 First bonding layer , 42 second bonding layer, 43 third bonding layer, 44 fourth bonding layer, 45 fifth bonding layer, 81 sample piece, 83 side (mounting side), 85 lead tape.

Claims (15)

A laminate in which a surface treatment film and a liquid crystal film are laminated,
The surface-treated film has a substrate layer, a coating layer provided on the surface of the substrate layer, and a first end portion where the coating layer is not provided on the surface of the substrate layer,
The liquid crystal film has a resin film and a liquid crystal layer, and the liquid crystal layer side faces the surface treatment film,
The resin film has a second end portion having an uneven region with a surface roughness Sa of 0.03 μm or more and 0.60 μm or less,
In the cross section of the laminate, the first end and the second end face each other, and the first position of the end of the coating layer on the first end side is the same as or inside the second position of the inner end of the uneven region of the second end. 2. The laminate according to claim 1, wherein said liquid crystal layer covers at least part of said uneven region. The coated region of the surface-treated film provided with the coating layer on the surface of the base layer has a puncture strength of 1.00 N or less at a temperature of 23 ° C. and a relative humidity of 55%,
The laminate according to claim 1 or 2, wherein the substrate layer has a puncture strength of 3.00 N or more at a temperature of 23°C and a relative humidity of 55%. The laminate according to any one of claims 1 to 3, wherein the surface-treated film has a tear strength of 0.5 N or more when the surface treatment film is torn from the first end at a temperature of 23°C and a relative humidity of 55%. The laminate according to any one of claims 1 to 4, wherein a distance L1 between said first position and said second position is 1 mm or more. The laminate according to any one of claims 1 to 5, wherein the first end and the second end are provided along a pair of opposite sides of the laminate when viewed from above. The laminate according to any one of claims 1 to 6, wherein the uneven region is a knurled portion. The laminate according to any one of claims 1 to 7, wherein the base material layer has a thickness of 20 µm or less. The laminate according to any one of claims 1 to 8, wherein the base material layer is a cyclic olefin resin film. The laminate according to any one of claims 1 to 9, wherein the coating layer is a cured product layer of a composition containing an ultraviolet curable resin. The laminate according to any one of claims 1 to 10, wherein the resin film is a cellulose resin film. At a temperature of 23 ° C. and a relative humidity of 55%, a cross hatch test performed by forming 100 cross hatches in the coating layer of the surface treatment film leaves 90 or more cross hatches on the base layer. Laminate according to any one of claims 1 to 11. The laminate is a long body,
The laminate according to any one of claims 1 to 12, wherein the first end and the second end are provided at both ends in the width direction of the laminate. 14. The laminate according to any one of claims 1 to 13, further comprising a linear polarizing layer between the surface-treated film and the liquid crystal film. A method for producing a polarizing plate having a linear polarizing layer and a surface-treated film laminated on one side of the linear polarizing layer,
A method for producing a polarizing plate, comprising the step of peeling the resin film from the laminate according to claim 14 .

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