WO2023090051A1 - Optical layered body - Google Patents

Abstract

[Problem] To provide an optical layered body that allows satisfactory peeling of a release film even if a phase difference layer and a linear polarization layer, containing a hardened layer of a composition including a polymerizable liquid crystal compound, are included. [Solution] The optical layered body has a surface-protecting film, a transparent resin film, a circular polarizing plate, a first adhesive layer, and a release film in this order. The surface-protecting film is peelable from the transparent resin film. The circular polarizing plate, in order from the transparent resin film side, has a linear polarization layer containing a first hardened layer of a first composition including a polymerizable liquid crystal compound and a first phase difference layer containing a second hardened layer of a second composition including a polymerizable liquid crystal compound. The release film is peelable from the first adhesive layer.

Description

optical laminate

The present invention relates to an optical laminate.

Display devices such as liquid crystal display devices and organic EL display devices use linear polarizing layers, retardation layers, and optical films such as laminates obtained by laminating these layers. As a linear polarizing layer, in addition to a PVA polarizing film in which a dichroic dye such as iodine is adsorbed and oriented on a polyvinyl alcohol-based resin film, a liquid crystal curing manufactured by applying a composition containing a polymerizable liquid crystal compound to a substrate. It is known to use layers (eg US Pat. As for the retardation layer, in addition to a retardation film which is a stretched film obtained by stretching a resin film, it is known to use a liquid crystal cured layer produced by applying a composition containing a polymerizable liquid crystal compound to a substrate. (For example, Patent Document 1).

JP 2017-83843 A

An optical film may have an adhesive layer for application to a display device and a release film for covering and protecting the adhesive layer. In such an optical film, it is necessary to peel off the release film to expose the pressure-sensitive adhesive layer. For example, when applied to a display device using an automatic laminating device or the like, an optical film in which an adhesive tape for peeling (hereinafter sometimes referred to as "peeling tape") is pasted on the surface of a peeling film is used. The peeling film is peeled off by raising the peeling tape while it is fixed on a suction stage having suction holes.

However, when the linear polarizing layer and the retardation layer contained in the optical film are liquid crystal cured layers, when the peeling film is peeled off using the peeling tape as described above, not only the peeling film but also the entire optical film is lifted. , it was found that the release film could not be peeled off. In order to peel off the release film, it is conceivable to increase the vacuum suction force of the holding table to increase the holding force of the optical film on the suction stage. There is The traces of the suction holes may hinder the inspection work of the optical film or adversely affect the optical performance of the optical film.

An object of the present invention is to provide an optical laminate capable of satisfactorily peeling off a release film even when a linear polarizing layer and a retardation layer including a cured layer of a composition containing a polymerizable liquid crystal compound are included. do.

The present invention provides the following optical layered body.
[1] Having a surface protective film, a transparent resin film, a circularly polarizing plate, a first pressure-sensitive adhesive layer, and a release film in this order,
The surface protection film is peelable from the transparent resin film,
The circularly polarizing plate includes, in order from the transparent resin film side, a linear polarizing layer including a first cured layer of a first composition containing a polymerizable liquid crystal compound, and a second composition of a second composition containing a polymerizable liquid crystal compound. Having a first retardation layer including a cured layer,
The optical layered body, wherein the release film is peelable from the first pressure-sensitive adhesive layer.
[2] a distance D from the surface of the surface protective film on the transparent resin film side to the surface of the first adhesive layer on the circularly polarizing plate side is 20 μm or more and 60 μm or less;
The optical laminate according to [1], wherein the transparent resin film has a tensile elastic modulus of 1500 MPa or more and 8000 MPa or less at a temperature of 23°C.
[3] The surface protection film has a second adhesive layer and a base film in order from the transparent resin film side,
The tensile elastic modulus of the base film at a temperature of 23° C. is 2500 MPa or more and 6000 MPa or less,
The optical laminate according to [1] or [2], wherein the base film has a thickness of 30 μm or more and 120 μm or less.
[4] The optical laminate according to any one of [1] to [3], further comprising a first bonding layer between the transparent resin film and the circularly polarizing plate.
[5] The optical laminate according to any one of [1] to [4], further comprising a diffusion prevention layer between the transparent resin film and the circularly polarizing plate.
[6] The optical laminate according to [5], wherein the anti-diffusion layer has a thickness of 5 μm or less.
[7] The optical laminate according to any one of [1] to [6], wherein the circularly polarizing plate has a second bonding layer bonding the linear polarizing layer and the first retardation layer.
[8] The polymerizable liquid crystal compound contained in the first composition is a polymerizable liquid crystal compound exhibiting a smectic liquid crystal phase,
The optical laminate according to any one of [1] to [7], wherein the first composition further contains a dye having absorption anisotropy.
[9] Any one of [1] to [8], wherein the second cured layer is cured with the polymerizable liquid crystal compound oriented horizontally with respect to the surface of the first retardation layer. An optical laminate as described.
[10] The circularly polarizing plate further comprises a second retardation layer comprising a third cured layer of a third composition containing a polymerizable liquid crystal compound on the side opposite to the linear polarization layer side of the first retardation layer. The optical laminate according to any one of [1] to [9], which has layers.
[11] The optical laminate according to [10], wherein the third cured layer is cured with the polymerizable liquid crystal compound oriented in a direction perpendicular to the surface of the second retardation layer.
[12] The adhesion force F1 between the surface protective film and the transparent resin film and the adhesion force F2 between the first pressure-sensitive adhesive layer and the release film satisfy the relationship of the following formula (1). , the optical laminate according to any one of [1] to [11].
|F1-F2|≧0.02 [N/25mm] (1)

According to the optical layered body of the present invention, the release film can be removed satisfactorily.

1 is a cross-sectional view schematically showing an optical layered body according to one embodiment of the present invention; FIG. FIG. 4 is a cross-sectional view schematically showing an optical layered body according to another embodiment of the present invention; FIG. 4A is a top view for explaining an example of a method for peeling a release film from the optical layered body according to the embodiment of the present invention. FIG. 4 is a cross-sectional view for explaining an example of a method for peeling a release film from the optical layered body according to the embodiment of the invention.

Preferred embodiments of the optical layered body will be described below with reference to the drawings.
(Optical laminate)
1 and 2 are cross-sectional views schematically showing optical laminates according to embodiments of the present invention. 3 and 4 are a top view and a cross-sectional view, respectively, for explaining an example of a method for peeling a release film from an optical layered body according to an embodiment of the present invention.

The optical laminates 1 and 2 shown in FIGS. 1 and 2 have a surface protective film 10, a transparent resin film 15, circularly polarizing plates 30 and 40, a first adhesive layer 21, and a release film 23 in this order.
As shown in FIG. 2, the optical laminate 2 may have a first anti-diffusion layer 35 (anti-diffusion layer) between the transparent resin film 15 and the circularly polarizing plate 40 .

The surface protective film 10 can be peeled off from the transparent resin film 15 and is in contact with the transparent resin film 15 . The surface protective film 10 can be peeled off from the transparent resin film 15 while maintaining the shapes of the surface protective film 10 and the transparent resin film 15 respectively. Surface protection film 10 may be a self-adhesive film. In this case, the surface protective film 10 is a self-adhesive film alone, which is in contact with the transparent resin film 15 as it is. As shown in FIGS. 1 and 2, the surface protection film 10 may have a second adhesive layer 12 and a first base film 11 (base film) in order from the transparent resin film 15 side. In this case, the second adhesive layer 12 forming the surface protection film 10 is in contact with the transparent resin film 15 .

The transparent resin film 15 and the circularly polarizing plates 30 and 40 may be in direct contact with each other, but as shown in FIGS. may have been For example, as shown in FIG. 1, when the optical laminate 1 does not have the first anti-diffusion layer 35 between the transparent resin film 15 and the circularly polarizing plate 30, the transparent resin film 15 and the circularly polarizing plate 30 are in direct contact with each other. Alternatively, each may be in direct contact with the first bonding layer 25 . For example, as shown in FIG. 2, when the optical laminate 2 has the first anti-diffusion layer 35 between the transparent resin film 15 and the circularly polarizing plate 40, the transparent resin film 15 and the first anti-diffusion layer 35 are directly Alternatively, each may be in direct contact with the first bonding layer 25 . The first anti-diffusion layer 35 and the circularly polarizing plate 40 are preferably in direct contact with each other, but may be laminated via a bonding layer (adhesive layer or adhesive layer).

The circularly polarizing plates 30 and 40 have a linear polarizing layer 31 and a first retardation layer 33 in this order from the transparent resin film 15 side. The linear polarizing layer 31 may be the outermost surface of the circularly polarizing plates 30 and 40 on the transparent resin film 15 side. The linear polarizing layer 31 and the first retardation layer 33 may be in direct contact with each other. Alternatively, as shown in FIGS. 1 and 2, the circularly polarizing plates 30 and 40 further bond the linearly polarizing layer 31 and the first retardation layer 33 to the second bonding layer 32 (adhesive layer or adhesive layer). layer), and the linear polarizing layer 31 and the first retardation layer 33 may each be in direct contact with the second bonding layer 32 .

The circularly polarizing plate 40 may further have a second anti-diffusion layer 36 between the linearly polarizing layer 31 and the first retardation layer 33, as shown in FIG. In this case, the second anti-diffusion layer 36 and the linear polarizing layer 31 are preferably in direct contact with each other, but may be laminated via a bonding layer (adhesive layer or adhesive layer). The second anti-diffusion layer 36 and the first retardation layer 33 may be in direct contact with each other, or may be laminated via a bonding layer (adhesive layer or adhesive layer).

The circularly polarizing plate 40 may further have a second retardation layer 38 on the side of the first retardation layer 33 opposite to the linear polarization layer 31 side, as shown in FIG. When the circularly polarizing plate 40 has the second retardation layer 38, the first retardation layer 33 and the second retardation layer 38 may be in direct contact, but as shown in FIG. It may have a third bonding layer 37 (adhesive layer or adhesive layer) that bonds 33 and the second retardation layer 38 together. In this case, it is preferable that the first retardation layer 33 and the second retardation layer 38 are in direct contact with the third bonding layer 37 respectively.

The circularly polarizing plate 40 may have one or more third retardation layers in addition to the first retardation layer 33 and the second retardation layer 38 . The lamination position of the third retardation layer is not particularly limited, for example, it may be laminated on the side opposite to the first retardation layer 33 side of the second retardation layer 38, It may be laminated between the two retardation layers 38 . The third retardation layer may be in direct contact with another layer, or may be laminated via a bonding layer (adhesive layer or pressure-sensitive adhesive layer).

The linear polarizing layer 31 includes a first cured layer of a first composition containing a polymerizable liquid crystal compound. The first retardation layer 33 includes a second cured layer of a second composition containing a polymerizable liquid crystal compound. The second retardation layer 38 preferably includes a second cured layer of a second composition containing a polymerizable liquid crystal compound. The third retardation layer preferably includes a third cured layer of a third composition containing a polymerizable liquid crystal compound.

It is preferable that the circularly polarizing plates 30 and 40 and the first adhesive layer 21 are in direct contact. The release film 23 can be peeled off from the first adhesive layer 21 and is in contact with the first adhesive layer 21 . The release film 23 can be peeled off from the first adhesive layer 21 while maintaining the shapes of the release film 23 and the first adhesive layer 21 . When the peeling film 23 is peeled off, the first adhesive layer 21 in contact therewith is exposed.

The optical laminates 1 and 2 are applied to a display device by laminating the first adhesive layer 21 exposed by peeling the release film 23 to a display element of a display device such as an organic EL display device. . When peeling the release film 23 from the optical laminates 1 and 2, first, as shown in FIGS. ) 45 is fixed by vacuum suction or the like so that the surface protection film 10 side faces the suction stage 46 side having suction holes. Thereafter, the optical laminates 1 and 2 are separated between the release film 23 and the first adhesive layer 21 by pulling the release tape 45 in the direction of the arrows shown in FIGS. 3 and 4 (a) to (c). The release film 23 is peeled off so that the .

In the optical laminates 1 and 2, the linear polarizing layer 31 and the first retardation layer 33 included in the circularly polarizing plates 30 and 40 are composed of a cured layer of a composition containing a polymerizable liquid crystal compound, and their thicknesses are small. The circularly polarizing plates 30 and 40 include, for example, a polyvinyl alcohol-based resin film, a PVA polarizing film in which a dichroic dye such as iodine is adsorbed and oriented, and a retardation film that is a stretched film obtained by stretching the resin film. Compared to the plate, the rigidity is small.

The optical laminates 1 and 2 have a transparent resin film 15 between the surface protective film 10 and the circularly polarizing plates 30 and 40. As a result, even if the circularly polarizing plates 30 and 40 have low rigidity as described above, the transparent resin film 15 can improve the rigidity of the optical laminates 1 and 2 . Therefore, the peeling film 23 can be suitably peeled off from the optical laminates 1 and 2 by lifting the peeling tape 45 as shown in FIGS. 4(a) to 4(c).

On the other hand, an optical layered body in which the linear polarizing layer and the first retardation layer are the cured layers described above and does not include a transparent resin film does not have sufficient rigidity. Therefore, when the peeling tape is lifted, not only the peeling film but also the optical layered body is lifted from the suction stage, making it difficult to peel off the peeling film. If the suction holding force of the optical layered body on the suction stage is increased in order to suppress the lifting of the optical layered body from the suction stage, the surface protection film and/or the circularly polarizing plate may leave marks of the suction holes. The traces of the suction holes formed in the optical layered body may hinder inspection work and may cause deterioration in display performance when the optical layered body is applied to a display device. On the other hand, according to the optical layered bodies 1 and 2 of the present embodiment, it is possible to prevent the release film 23 from being satisfactorily peeled off and to prevent the optical layered bodies 1 and 2 from leaving traces of suction holes. can be done.

In the optical laminates 1 and 2, the distance D from the surface of the surface protection film 10 on the transparent resin film 15 side to the surface of the first adhesive layer 21 on the circularly polarizing plate 30 and 40 side is preferably 20 μm or more. Preferably, it may be greater than 20 μm, may be 25 μm or more, or may be 30 μm or more, and may be preferably 60 μm or less, may be 55 μm or less, or may be 50 μm or less. It may be 40 μm or less. When the distance D is within the range described above, the tensile elastic modulus of the transparent resin film 15 at a temperature of 23° C. is within the range of 1500 MPa or more and 8000 MPa or less, as will be described later. can be peeled off even better.

In the optical laminates 1 and 2, the adhesion force F1 between the surface protection film 10 and the transparent resin film 15 and the adhesion force F2 between the first pressure-sensitive adhesive layer 21 and the release film 23 are expressed by the formula (1) It is preferable to satisfy the relationship of
|F1-F2|≧0.02 [N/25mm] (1)

The adhesion force F1 is the peeling force when peeling the surface protective film 10 from the optical laminates 1 and 2, and is the force required to separate the surface protective film 10 from the transparent resin film 15 in the optical laminates 1 and 2. Equivalent to. The adhesion force F2 is a peeling force when peeling the release film 23 from the optical layered bodies 1 and 2, and is required when separating the release film 23 from the first adhesive layer 21 in the optical layered bodies 1 and 2. equivalent to force.

|F1-F2| may be 0.03 N/25 mm or more, may be 0.04 N/25 mm or more, may be 0.20 N/25 mm or less, or may be 0.10 N/25 mm or less, or 0.08 N/25 mm or less.

When the adhesion force F1 and the adhesion force F2 satisfy the relationship of the above formula (1), the peeling force when peeling the surface protective film 10 and the peeling film 23 from the optical layered bodies 1 and 2 has a moderate strength relationship. be able to. Thereby, the surface protective film 10 and the peeling film 23 can be peeled off in a desired order. For example, when peeling the release film 23 from the optical layered bodies 1 and 2 first, the adhesion force F2 should be smaller than the adhesion force F1, and the surface protective film 10 is peeled from the optical layered bodies 1 and 2 first. In that case, the adhesion force F1 should be made smaller than the adhesion force F2.

The adhesion force F1 may be, for example, 0.04 N/25 mm or more, 0.06 N/25 mm or more, 0.08 N/25 mm or more, or 0.30 N/25 mm. or less, 0.25 N/25 mm or less, 0.20 N/25 mm or less, or 0.15 N/25 mm or less. When the adhesion force F1 is within the above range, the surface protective film 10 can be easily peeled off from the optical laminates 1 and 2 .

The adhesion force F2 may be, for example, 0.01 N/25 mm or more, 0.02 N/25 mm or more, 0.03 N/25 mm or more, or 0.05 N/25 mm or more. 0.30 N/25 mm or less, 0.25 N/25 mm or less, 0.20 N/25 mm or less, or 0.15 N/25 mm or less There may be. When the adhesion force F2 is within the above range, the release film 23 can be easily peeled off from the optical layered bodies 1 and 2 .

The adhesion force F1 and the adhesion force F2 are the surface of the surface protection film 10 on the side in contact with the transparent resin film 15 and the first adhesive of the release film 23, which adjusts the type and thickness of the surface protection film 10 and the release film 23. It can be adjusted by, for example, modifying the surface of the side in contact with the layer 21 .

The adhesion force F1 and the adhesion force F2 can be measured by the method described in Examples described later, and can be measured according to the 90° peeling test method specified in JIS K 6854-1:1999.

The details of each member constituting the optical layered body and the members used to manufacture the optical layered body will be described below.

(Surface protection film)
The surface protective film 10 exists on the outermost layer of the optical laminates 1 and 2 and is provided so as to be peelable from the transparent resin film 15 . The surface protection film 10 is used to cover and protect the surface of the transparent resin film.

The thickness of the surface protective film 10 may be, for example, 30 μm or more, 40 μm or more, or 50 μm or more, or may be 150 μm or less, or 120 μm or less. , 100 μm or less, or 90 μm or less.

As described above, the surface protection film 10 may have a multilayer structure of the first base film 11 and the second adhesive layer 12, or a self-adhesive single-layer structure composed of the first base film 11. It may be a flexible film. The surface protective film 10 may further have antistatic properties and/or antifouling properties.

The tensile elastic modulus of the first base film 11 at a temperature of 23° C. may be, for example, 2500 MPa or more, 3000 MPa or more, 3500 MPa or more, or 6000 MPa or less. , 5500 MPa or less.

The thickness of the first base film 11 may be, for example, 30 μm or more, 35 μm or more, 40 μm or more, 50 μm or more, or 120 μm or less. 100 μm or less, or 80 μm or less.

When the tensile elastic modulus of the first base film 11 is within the above range and the thickness is within the above range, the release film 23 can be easily peeled off from the optical laminates 1 and 2, and the release film The optical laminates 1 and 2 from which 23 has been peeled off can be easily and satisfactorily attached to the display device. The tensile elastic modulus of the first base film 11 can be measured by the method described in Examples below.

For the first base film 11, for example, a film formed using a resin known in the field of optical films, or the like can be used. Examples of the resin constituting the first base film include polyolefins such as polyethylene and polypropylene; cyclic olefin resins such as norbornene-based polymers; polyvinyl alcohol; polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; meth)acrylic acid ester; cellulosic resins such as triacetylcellulose, diacetylcellulose and cellulose acetate propionate; polycarbonate; polysulfone; polyethersulfone; polyetherketone; Among them, at least one selected from cyclic olefin resins, cellulose resins, and polyesters is preferable from the viewpoint of smoothness and quality as a coating substrate. These resins may be used alone or in combination of two or more. The above resin can be formed into a film by known means such as a solvent casting method and a melt extrusion method. "(Meth)acryl" means at least one selected from acryl and methacryl.

When the surface protective film 10 has self-adhesiveness, it can be formed using a polypropylene-based resin, a polyethylene-based resin, or the like.

When the surface protection film 10 has antistatic properties and/or antifouling properties, the first base film 11 may have antistatic properties and/or antifouling properties. A surface functional layer having antistatic properties and/or antifouling properties may be laminated on the surface. The surface functional layer is preferably in direct contact with the first base film 11, and when the surface protective film 10 has the second adhesive layer 12, the surface functional layer is the second adhesive layer of the first base film 11. It is preferably provided on the side opposite to the agent layer 12 side.

In order to impart desired releasability and/or adhesion, the first base film 11 is subjected to corona treatment, plasma treatment, flame treatment, etc., depending on the type of layer adjacent to the first base film 11, etc. surface modification treatment may be applied.

(transparent resin film)
The transparent resin film 15 is provided to provide the optical laminates 1 and 2 with appropriate rigidity. The tensile elastic modulus of the transparent resin film at a temperature of 23° C. is preferably 1500 MPa or higher, may be 1800 MPa or higher, may be 2000 MPa or higher, may be 3000 MPa or higher, and may be 8000 MPa or lower. 7000 MPa or less, 6000 MPa or less, or 5000 MPa or less. The tensile elastic modulus of the transparent resin film 15 can be measured by the method described in Examples below.

Since the tensile elastic modulus of the transparent resin film 15 is within the above range, even when the distance D of the optical laminates 1 and 2 is within the range of 20 μm or more and 60 μm or less, the optical laminates 1 and 2 can be maintained. 2 can be imparted with appropriate rigidity. Thereby, as described above, the release film 23 can be preferably peeled off by using the peeling tape 45 (FIGS. 3 and 4) while suppressing the traces of the suction holes from remaining on the optical laminates 1 and 2. can be done.

The thickness of the transparent resin film 15 may be, for example, 5 m or more, 10 μm or more, 12 μm or more, 15 μm or more, or 40 μm or less. , 30 μm or less, or 25 μm or less.

For the transparent resin film 15, for example, a film formed using a resin known in the field of optical films, or the like can be used. Examples of the resin forming the transparent resin film 15 include the resin forming the first base film 11 described above. Among them, at least one selected from cyclic olefin-based resins, cellulose-based resins, and polyesters is preferable. The above resin can be formed into a film by known means such as a solvent casting method and a melt extrusion method.

The transparent resin film 15 is subjected to surface modification treatment such as corona treatment, plasma treatment, flame treatment, etc., depending on the type of layer adjacent to the transparent resin film 15 in order to impart desired adhesion. good too.

(Circularly polarizing plate)
The circularly polarizing plates 30 and 40 can convert the light incident from the linearly polarizing layer 31 side into linearly polarized light, and convert the linearly polarized light into circularly polarized light. When this converted circularly polarized light is reflected and again enters the circularly polarizing plates 30 and 40 from the side of the first retardation layer 33, the circularly polarizing plates 30 and 40 convert the circularly polarized light into linearly polarized light. Polarized light can be absorbed by the linearly polarizing layer.

The linear polarizing layer 31 and the first retardation layer 33 are laminated directly or via the second anti-diffusion layer 36 and/or the second bonding layer 32 . The adhesion between the linear polarizing layer 31 and the first retardation layer 33 is usually 2N/25mm or more. The linear polarizing layer 31 and the first retardation layer 33 may be laminated with such an adhesion force as to cause so-called material destruction without causing separation between them. The adhesion force between the linear polarizing layer 31 and the first retardation layer 33 is determined according to JIS K 6854-1: 1999, as described in the method for measuring the adhesion force F1 and the adhesion force F2 described in Examples below. It can be measured according to the specified 90° peel test method.

(linear polarizing layer)
The linear polarizing layer 31 has a 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 31 includes a first cured layer of a first composition containing a polymerizable liquid crystal compound, and may include a first alignment layer for orienting the polymerizable liquid crystal compound.

The polymerizable liquid crystal compound contained in the first composition is a compound that contains at least one polymerizable group and exhibits liquid crystallinity. The polymerizable liquid crystal compound may be a compound exhibiting absorption anisotropy, and when the polymerizable liquid crystal compound exhibits absorption anisotropy, the first composition should not contain a dye exhibiting absorption anisotropy. good too.

A polymerizable group means a group that can participate in a polymerization reaction by an active radical or acid generated from a polymerization initiator, and is preferably a photopolymerizable group. Examples of the polymerizable group include vinyl group, vinyloxy group, 1-chlorovinyl group, isopropenyl group, 4-vinylphenyl group, (meth)acryloyl group, oxiranyl group and oxetanyl group. Among them, a radically polymerizable group is preferred, a (meth)acryloyl group, a vinyl group, and a vinyloxy group are more preferred, and a (meth)acryloyl group is even more preferred.

The polymerizable liquid crystal compound contained in the first composition is preferably a compound exhibiting smectic liquid crystallinity. By using a polymerizable liquid crystal compound exhibiting smectic liquid crystallinity, a linear polarizing layer having a high degree of orientational order can be formed. From the viewpoint of realizing a higher degree of alignment order, the liquid crystal state exhibited by the polymerizable liquid crystal compound is more preferably a high-order smectic phase (high-order smectic liquid crystal state). Here, the higher order smectic phase includes smectic B phase, smectic D phase, smectic E phase, smectic F phase, smectic G phase, smectic H phase, smectic I phase, smectic J phase, smectic K phase and smectic L phase. Among these, smectic B phase, smectic F phase and smectic I phase are more preferable. Thermotropic liquid crystals or lyotropic liquid crystals may be used as liquid crystals, but thermotropic liquid crystals are preferred because they allow precise film thickness control. Moreover, the polymerizable liquid crystal compound may be a monomer, but may be an oligomer or a polymer in which a polymerizable group is polymerized.

The first composition may contain a dye exhibiting absorption anisotropy in addition to the polymerizable liquid crystal compound. A dye having absorption anisotropy means a dye having different absorbance in the long-axis direction and the short-axis direction of the molecule. The dye exhibiting absorption anisotropy is not particularly limited as long as it has the above properties, and may be a dye or a pigment. Also, two or more dyes or pigments may be used in combination, or a dye and a pigment may be used in combination.

As the dye having absorption anisotropy, one having a maximum absorption wavelength (λ _MAX ) in the wavelength range of 300 nm to 700 nm is preferable. Dyes having such absorption anisotropy include, for example, acridine dyes, oxazine dyes, cyanine dyes, naphthalene dyes, azo dyes and anthraquinone dyes. Among them, azo dyes are preferred. Examples of azo dyes include monoazo dyes, bisazo dyes, trisazo dyes, tetrakis azo dyes, and stilbene azo dyes, with bisazo dyes and trisazo dyes being preferred. Examples of dyes having absorption anisotropy include those exemplified in JP-A-2013-101328.

In addition to the polymerizable liquid crystal compound and the dye having absorption anisotropy described above, the first composition includes a solvent, a polymerization initiator such as a photopolymerization initiator, a photosensitizer, a polymerization inhibitor, a leveling agent, and an antioxidant. agents, release agents, stabilizers, colorants, flame retardants, lubricants, and the like. For these, known ones can be used, for example, those exemplified in JP-A-2017-102479 and JP-A-2017-83843 can be used.

The linear polarizing layer 31 may include a first alignment layer. The first alignment layer may be provided on the first retardation layer 33 side of the first cured layer, or may be provided on the transparent resin film 15 side of the first cured layer.

The first alignment layer has an alignment control force that aligns the polymerizable liquid crystal compound in a desired direction. The first alignment layer preferably has solvent resistance that does not dissolve when the first composition is applied or the like, and has heat resistance to heat treatment for removing the solvent and for aligning the polymerizable liquid crystal compound. The first alignment layer includes an alignment polymer layer made of an alignment polymer, a photo-alignment polymer layer made of a photo-alignment polymer, and a groove alignment layer having an uneven pattern or a plurality of grooves on the layer surface. can be mentioned. The first alignment layer is preferably a photo-alignment polymer layer from the viewpoint of alignment angle precision and quality. Examples of the first alignment layer include those exemplified in JP-A-2013-33249.

The linear polarizing layer 31 can be manufactured by the manufacturing method of the polarizing layer described in JP-A-2013-33249. The first cured layer can be formed, for example, by coating the first composition on the first alignment layer to form a coating film and solidifying (curing) the coating film. Alternatively, the first cured layer may be formed by coating the first composition on the substrate layer to form a coating film, and stretching the coating film together with the substrate layer.

(First retardation layer, second retardation layer, third retardation layer)
The first retardation layer 33 includes a second cured layer of a second composition containing a polymerizable liquid crystal compound, and may include a second alignment layer for orienting the polymerizable liquid crystal compound. The second retardation layer 38 includes a third cured layer of a third composition containing a polymerizable liquid crystal compound, and may include a third alignment layer for orienting the polymerizable liquid crystal compound. The third retardation layer includes a fourth cured layer of a fourth composition containing a polymerizable liquid crystal compound, and may include a fourth alignment layer for orienting the polymerizable liquid crystal compound. The second to fourth alignment layers may be provided on the linear polarizing layer 31 side of the second to fourth cured layers, respectively, and the first adhesive layer 21 of the second to fourth cured layers may be provided. It may be provided on the side.

As shown in FIG. 1, when the circularly polarizing plate 30 has the linear polarizing layer 31 and the first retardation layer 33, the second cured layer included in the first retardation layer 33 is composed of the polymerizable liquid crystal compound as the first It is preferable that the film is cured while being oriented horizontally with respect to the surface of the retardation layer 33 .

The first retardation layer 33 is preferably a λ/4 retardation layer that satisfies the relationship shown in formula (2) below.
120 nm≦Re(550)≦170 nm (2)
[In formula (2), Re(550) represents the in-plane retardation value of the first retardation layer at a wavelength of 550 nm. ]

In formula (2), the in-plane retardation value Re(550) may be 125 nm or more, or 130 nm or more, or may be 165 nm or less, or may be 160 nm or less. .

More preferably, the first retardation layer 33 is a reverse wavelength dispersion λ/4 retardation layer that satisfies the above formula (2) and the following formulas (3) and (4).
Re(450)/Re(550)≤1.00 (3)
Re(650)/Re(550)≧1.00 (4)
[In formulas (3) and (4),
Re (450) represents the in-plane retardation value of the first retardation layer at a wavelength of 450 nm,
Re (550) represents the in-plane retardation value of the first retardation layer at a wavelength of 550 nm,
Re(650) represents the in-plane retardation value of the first retardation layer at a wavelength of 650 nm. ]

In formula (3), Re(450)/Re(550) may be 0.70 or more, 0.78 or more, or 0.92 or less. It may be 0.90 or less, 0.87 or less, 0.86 or less, or 0.85 or less. In formula (4), Re(650)/Re(550) may be 1.01 or more, or 1.02 or more.

As shown in FIG. 2, when the circularly polarizing plate 40 has the linear polarizing layer 31, the first retardation layer 33, and the second retardation layer 38, the combination of the first retardation layer 33 and the second retardation layer 38 Examples include [i] a combination of a λ/4 retardation layer and a positive C layer, and [ii] a combination of a λ/2 retardation layer and a λ/4 retardation layer.

When the first retardation layer 33 is a λ / 4 retardation layer, as described above, the polymerizable liquid crystal compound is cured in a state aligned in the horizontal direction with respect to the surface of the first retardation layer 33. is preferred.
When the second retardation layer 38 is a λ/4 retardation layer, the third cured layer included in the second retardation layer 38 has a polymerizable liquid crystal compound in the horizontal direction with respect to the surface of the second retardation layer 38. It is preferably cured in a state of orientation. Furthermore, when the first retardation layer 33 or the second retardation layer 38 is a λ / 4 retardation layer, it is preferable to satisfy the relationship of the above formula (2), and in addition to the above formula (2), the above (3 ) and (4) may be satisfied.

In the case of [i] above, when the first retardation layer 33 is a positive C layer, the second cured layer included in the first retardation layer 33 is the polymerizable liquid crystal compound of the first retardation layer 33 It is preferably cured in a state of being oriented in the direction perpendicular to the plane of the . In the case of [i] above, when the second retardation layer 38 is a positive C layer, the third cured layer included in the second retardation layer 38 contains a polymerizable liquid crystal compound in the second retardation layer 38 It is preferably cured in a state of being oriented in the direction perpendicular to the plane of the .

The positive C layer preferably satisfies the relationship of formula (5) below.
−100 nm≦Rth(550)≦−40 nm (5)
[In formula (5), Rth(550) represents a retardation value in the thickness direction of the first retardation layer or the second retardation layer at a wavelength of 550 nm. ]

In formula (5), the thickness direction retardation value Rth(550) may be −90 nm or more, −80 nm or more, or −50 nm or less.

In the case of [ii] above, when the first retardation layer 33 is a λ / 2 retardation layer, the second cured layer included in the first retardation layer 33 has a polymerizable liquid crystal compound in the first place. It is preferable that the phase difference layer 33 is cured while being oriented in the horizontal direction. In the case of [ii] above, when the second retardation layer 38 is a λ / 2 retardation layer, the third cured layer included in the second retardation layer 38 has a polymerizable liquid crystal compound in the second order. It is preferable that the film is cured while being oriented horizontally with respect to the plane of the retardation layer 38 .

The λ/2 retardation layer preferably satisfies the relationship of formula (6) below.
200 nm≦Re(550)≦300 nm (6)
[In formula (6), Re(550) represents an in-plane retardation value of the first retardation layer or the second retardation layer at a wavelength of 550 nm. ]

In Equation (6), the in-plane retardation value Re(550) may be 220 nm or more and may be 280 nm or less.

The in-plane retardation values Re(550) and Re(450) and the thickness direction retardation value Rth(550) can be determined, for example, by measurement using a retardation measuring device.

A known polymerizable liquid crystal compound can be used as the polymerizable liquid crystal compound for forming the second cured layer, the third cured layer, and the fourth cured layer. 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 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 display device, 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, JP-A-2007-108732 (paragraphs [0020] to [0067], etc.), JP-A-2010-244038 (paragraphs [0013] to [0108], etc.) described in can be preferably used.

The polymerizable group possessed by the polymerizable liquid crystal compound means a group involved in the polymerization reaction as described above, 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 layer of the polymerizable liquid crystal compound, at least one type preferably has two or more polymerizable groups in the molecule. "(Meth)acryloyl" means at least one selected from acryloyl and methacryloyl.

The liquid crystallinity exhibited by the polymerizable liquid crystal compound may be a thermotropic liquid crystal or a lyotropic liquid crystal, but the thermotropic liquid crystal is preferable in that it enables precise film thickness control. Further, the phase-ordered structure of the thermotropic liquid crystal may be nematic liquid crystal, smectic liquid crystal, or discotic liquid crystal. A polymerizable liquid crystal compound can be used individually or in combination of 2 or more types.

A polymerizable liquid crystal compound having a so-called T-shaped or H-shaped molecular structure tends to exhibit reverse wavelength dispersion when polymerized and cured, and a polymerizable liquid crystal compound having a T-shaped molecular structure has a stronger property. It tends to exhibit reverse wavelength dispersion.

The first retardation layer 33, the second retardation layer 38, and the third retardation layer may respectively include a second alignment layer, a third alignment layer, and a fourth alignment layer. The second to fourth alignment layers have an alignment control force to align the polymerizable liquid crystal compound in a desired direction. The second alignment layer to the fourth alignment layer may each independently be a vertical alignment layer in which the molecular axis of the polymerizable liquid crystal compound is vertically aligned with respect to the plane direction of the display device, and the molecules of the polymerizable liquid crystal compound It may be a horizontal alignment layer in which the axis is horizontally aligned with respect to the plane direction of the display device, or an inclined alignment layer in which the molecular axis of the polymerizable liquid crystal compound is tilted with respect to the plane direction of the display device, A photo-aligned polymer layer is preferable from the viewpoint of alignment angle accuracy and quality.

The second to fourth alignment layers have a solvent resistance that does not dissolve when the second to fourth compositions containing the polymerizable liquid crystal compound are applied, etc., and the removal of the solvent and the alignment of the polymerizable liquid crystal compound It is preferable to use a material having heat resistance to the heat treatment for the purpose. As the second to fourth alignment layers, each independently, an alignment polymer layer formed of an alignment polymer, a photo-alignment polymer layer formed of a photo-alignment polymer, an uneven pattern or a plurality of layers on the layer surface. Grooved alignment layers with grooves can be mentioned.

The second composition to the fourth composition each contain a polymerizable liquid crystal compound, a solvent, and various additives as necessary. The second cured layer to the fourth cured layer are formed by applying the second composition to the fourth composition on the second alignment layer to the fourth alignment layer, respectively, to form a coating film, and solidifying (curing) the coating film. ). Alternatively, the second to fourth compositions are applied on the substrate layer to form a coating film, and the coating film is stretched together with the substrate layer to form the second to fourth cured layers. may Additives contained in the second to fourth compositions include polymerization initiators, reactive additives, leveling agents, polymerization inhibitors, and the like. Known solvents, polymerization initiators, reactive additives, leveling agents, polymerization inhibitors and the like can be used as appropriate.

A film obtained by forming a resin can be used as the base material layer, and for example, a film using the resin constituting the above-described first base material film can be used. The thickness of the substrate layer is not particularly limited, but in general, it is preferably 1 to 300 μm or less, more preferably 20 to 200 μm, more preferably 30 to 120 μm from the viewpoint of workability such as strength and handleability. is more preferred. The substrate layer may be incorporated in the display device together with the first to third retardation layers, and the substrate layer is peeled off to form only the second cured layer to the fourth cured layer, or the second A stiffening layer and a second alignment layer, a third stiffening layer and a third alignment layer, or a fourth stiffening layer and a fourth alignment layer may be incorporated into the display device. When the substrate layer is incorporated into a display device, the thickness of the substrate layer may be less than 30 μm, for example 25 μm or less.

The thicknesses of the first to third retardation layers may each independently be 0.1 μm or more, may be 0.2 μm or more, may be 3 μm or less, and may be 2 μm. It may be below.

(First adhesive layer, second adhesive layer)
The first adhesive layer 21 and the second adhesive layer 12 are adhesive layers formed using an adhesive composition. The pressure-sensitive adhesive composition or the reaction product of the pressure-sensitive adhesive composition develops adhesiveness by attaching itself to an adherend such as a display element of a display device, and is called a so-called pressure-sensitive adhesive. It is a thing. 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, known pressure-sensitive adhesives having excellent optical transparency can be used without particular limitation. can use objects. 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 is obtained by blending an ultraviolet-curable compound such as a polyfunctional acrylate with the above-described pressure-sensitive adhesive composition, and curing the layer formed by coating with ultraviolet rays. can form a harder pressure-sensitive adhesive layer. Active energy ray-curable pressure-sensitive adhesives have the property of being cured by being irradiated with energy rays such as ultraviolet rays and electron beams. Since the active energy ray-curable adhesive has adhesiveness even before energy ray irradiation, it adheres to the adherend and has the property that it can be 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 optionally contain an antioxidant, a tackifier, a thermoplastic resin, a filler, a flow control agent, a plasticizer, an antifoaming agent, and an antistatic agent. , solvents and other additives.

The thicknesses of the first pressure-sensitive adhesive layer 21 and the second pressure-sensitive adhesive layer 12 are not particularly limited. It may be 20 μm or more, 25 μm or more, 300 μm or less, 250 μm or less, 100 μm or less, or 50 μm or less.

(First anti-diffusion layer, second anti-diffusion layer)
The first anti-diffusion layer 35 and the second anti-diffusion layer 36 are a dye having absorption anisotropy in the linear polarizing layer 31 or a polymerizable liquid crystal compound having absorption anisotropy (hereinafter both are collectively referred to as “absorption anisotropy”). It is used to suppress the diffusion of the dye (sometimes referred to as a "colorant") to other layers.

The first anti-diffusion layer 35 is provided between the transparent resin film 15 and the circularly polarizing plate 40, the second anti-diffusion layer constitutes the circularly polarizing plate 40, the linearly polarizing layer 31 and the first retardation layer 33 provided between The optical layered body 2 having the first anti-diffusion layer 35 and/or the second anti-diffusion layer 36 suppresses degradation of optical properties over time due to diffusion of the absorption anisotropic dye when incorporated into a display device. can do.

The first diffusion prevention layer 35 and the second diffusion prevention layer 36 are not particularly limited as long as they are layers capable of suppressing the diffusion of the absorption anisotropic dye. As the first diffusion prevention layer 35 and the second diffusion prevention layer 36, each independently, for example, a layer formed from a resin composition containing a water-soluble polymer, a curable composition containing an active energy ray-curable resin Layers to be formed and the like can be mentioned.

Since the water-soluble polymer is significantly different in polarity from the absorption anisotropic dye, the first diffusion prevention layer 35 and the second diffusion prevention layer 36 formed from a resin composition containing a water-soluble polymer have anisotropic absorption. Diffusion of pigment can be suppressed. Examples of water-soluble polymers that can form the first diffusion prevention layer 35 and the second diffusion prevention layer 36 include polyacrylamide-based polymers; polyvinyl alcohol, ethylene-vinyl alcohol copolymers, (meth)acrylic acid or its anhydride. carboxyvinyl-based polymers; polyvinylpyrrolidone; starches; sodium alginate; polyethylene oxide-based polymers and the like. These polymers may be used alone or in combination of two or more.

When the first diffusion prevention layer 35 and the second diffusion prevention layer 36 are layers formed from a resin composition containing a water-soluble polymer, the content of the water-soluble polymer in the layer is preferably 75% by mass or more. , more preferably 80% by mass or more, and still more preferably 85% by mass or more.

The resin composition containing a water-soluble polymer introduces a crosslinked structure for enhancing the denseness of the first anti-diffusion layer 35 and the second anti-diffusion layer 36 to improve the function of suppressing the diffusion of the absorption anisotropic dye. For this purpose, a cross-linking agent may be included. Examples of cross-linking agents include ionic cross-linking agents such as glyoxylate, water-soluble cross-linking agents such as epoxy cross-linking agents; isocyanate cross-linking agents, polyvalent aldehyde cross-linking agents such as glyoxal and glyoxal derivatives, and zirconium chloride. and hydrophobic cross-linking agents such as metal compound-based cross-linking agents such as titanium lactate-based cross-linking agents. The content of the cross-linking agent in the resin composition containing the water-soluble polymer may be, for example, 0.1 parts by mass or more, or may be 1 part by mass or more, with respect to 100 parts by mass of the water-soluble polymer. It may be 10 parts by mass or more, 100 parts by mass or less, 50 parts by mass or less, or 30 parts by mass or less.

A resin composition containing a water-soluble polymer is prepared as a solution in which the water-soluble polymer is dissolved in a solvent. The solvent may be selected according to the type of water-soluble polymer, and examples thereof include water, alcohol, and mixtures of water and alcohol, with water being preferred.

The solid content concentration of the resin composition containing the water-soluble polymer may be, for example, 1% by mass or more, may be 2% by mass or more, may be 50% by mass or less, or may be 30% by mass. It may be below.

A resin composition containing a water-soluble polymer may contain additives such as a preservative and a leveling agent in addition to the water-soluble polymer, cross-linking agent, and solvent. The content of the additive in the resin composition containing the water-soluble polymer may be, for example, 10% by mass or less, or 5% by mass or less, relative to the solid content of the resin composition.

The first anti-diffusion layer 35 and the second anti-diffusion layer 36 formed from a resin composition containing a water-soluble polymer are formed on the surface forming the first anti-diffusion layer 35 and the second anti-diffusion layer 36 (for example, a circularly polarizing plate It can be formed by applying the resin composition to the linear polarizing layer 31) of 30 and 40 and drying it. The drying treatment can be performed by, for example, blowing hot air. The drying temperature may be, for example, 40° C. or higher, 60° C. or lower, or 100° C. or lower, and the drying time may be, for example, 10 seconds or more and 600 seconds or less. .

Since the active energy ray-curable resin can be highly polymerized, the first diffusion prevention layer 35 and the second diffusion prevention layer 36 formed from a curable composition containing the active energy ray-curable resin are composed of the absorption anisotropic dye diffusion can be suppressed. Examples of the curable composition include a cationic polymerizable curable composition containing a cationic polymerizable compound as a curable compound, a radical polymerizable curable composition containing a radical polymerizable compound as a curable compound, a cationically polymerizable compound, and Examples thereof include hybrid-type curable compositions containing both radically polymerizable compounds. Specific examples of cationic polymerizable compounds include epoxy compounds having one or more epoxy groups in the molecule, oxetane compounds having one or more oxetane rings in the molecule, and vinyl compounds. Further, specific examples of radically polymerizable compounds include (meth)acrylic compounds having one or more (meth)acryloyl groups in the molecule, vinyl compounds, and the like. The curable composition can contain one or more cationically polymerizable compounds and/or can contain one or more radically polymerizable compounds.

The cationic polymerizable compound, which is the main component of the cationic polymerizable curable composition, is a compound that undergoes a cationic polymerization reaction and is cured by irradiation with active energy rays such as ultraviolet rays, visible light, electron beams, and X-rays, or by heating. It refers to oligomers, and examples thereof include epoxy compounds, oxetane compounds, and vinyl compounds. Among them, epoxy compounds are preferred.

An epoxy compound is a compound having one or more, preferably two or more epoxy groups in the molecule. An epoxy compound may be used individually by 1 type, and may use 2 or more types together. Examples of epoxy compounds include alicyclic epoxy compounds, aromatic epoxy compounds, hydrogenated epoxy compounds, and aliphatic epoxy compounds. Among them, the epoxy compound preferably contains an alicyclic epoxy compound and/or an aliphatic epoxy compound from the viewpoint of weather resistance, curing speed and adhesiveness.

When the curable composition contains an epoxy compound as a cationically polymerizable compound, the content of the epoxy compound may be 10 parts by mass or more, or 15 parts by mass with respect to 100 parts by mass of the solid content of the curable composition. 20 parts by mass or more, 70 parts by mass or less, 60 parts by mass or less, or 50 parts by mass or less.

When the total amount of curable compounds contained in the curable composition is 100% by mass, the content of the cationic polymerizable compound (the total content when two or more cationic polymerizable compounds are included) is It may be 50% by mass or more, 60% by mass or more, or 70% by mass or more. In addition, the curable composition may further contain a polymer component (thermoplastic resin, etc.).

When the curable composition contains a cationic polymerizable compound, it preferably contains a photocationic polymerization initiator. The photocationic polymerization initiator generates cationic species or Lewis acid upon irradiation with active energy rays such as visible light, ultraviolet rays, X-rays, or electron beams, and initiates the polymerization reaction of the cationic curable compound. Since the photocationic polymerization initiator acts catalytically with light, it is excellent in storage stability and workability even when mixed with a photocationically curable compound. Compounds that generate cationic species or Lewis acids upon irradiation with active energy rays include, for example, onium salts such as aromatic iodonium salts and aromatic sulfonium salts, aromatic diazonium salts, iron-arene complexes, and the like.

The photocationic polymerization initiator may be used alone or in combination of two or more. Among them, aromatic sulfonium salts are preferably used because they have ultraviolet absorption properties even in a wavelength region around 300 nm, and can give a cured product having excellent curability and good mechanical strength and adhesive strength.

The content of the photocationic polymerization initiator in the curable composition may be 1 part by mass or more, or may be 2 parts by mass or more, with respect to 100 parts by mass of the solid content of the curable compound. It may be 10 parts by mass or less, or may be 8 parts by mass or less. When the content of the photocationic polymerization initiator is within the above range, the cationic polymerizable compound can be sufficiently cured, and the first diffusion prevention layer 35 and the second diffusion prevention layer 36 have high mechanical strength and adhesive strength. can be given.

A hybrid-type curable composition can be obtained by adding a radically polymerizable compound to a curable composition containing a cationic polymerizable compound. By using a radical polymerizable compound together, the effect of increasing the hardness and mechanical strength of the first diffusion prevention layer 35 and the second diffusion prevention layer 36 can be expected, and the viscosity and curing speed of the curable composition can be adjusted. becomes easier to do.

The radically polymerizable compound refers to a compound or oligomer that undergoes a radical polymerization reaction by irradiation with active energy rays such as ultraviolet rays, visible light, electron beams, and X-rays or by heating. can be mentioned. Compounds having an ethylenically unsaturated bond include (meth)acrylic compounds having one or more (meth)acryloyl groups in the molecule, as well as styrene, styrenesulfonic acid, vinyl acetate, vinyl propionate, and N-vinyl. vinyl compounds such as -2-pyrrolidone; Among them, preferred radically polymerizable compounds are (meth)acrylic compounds.

The (meth)acrylic compound is a compound having at least one (meth)acryloyloxy group in the molecule, and may be a monomer, oligomer or polymer. Examples of (meth)acrylic compounds include (meth)acrylate compounds such as monofunctional (meth)acrylate compounds and polyfunctional (meth)acrylate compounds; urethane (meth)acrylate compounds such as polyfunctional urethane (meth)acrylate compounds; Epoxy (meth)acrylate compounds such as polyfunctional epoxy (meth)acrylate compounds; carboxyl group-modified epoxy (meth)acrylate compounds, polyester (meth)acrylate compounds, and the like. The (meth)acrylic compounds may be used singly or in combination of two or more.

The (meth)acrylate compounds include monofunctional (meth)acrylate compounds having one (meth)acryloyloxy group in the molecule, and polyfunctional (meth)acrylate compounds having two or more (meth)acryloyloxy groups in the molecule. Acrylate compounds are mentioned.

When using a polyfunctional (meth)acrylate compound, the crosslink density of the first diffusion prevention layer 35 and the second diffusion prevention layer 36 can be adjusted by controlling the molecular weight between crosslink points and the number of crosslink points of the compound. More specifically, the smaller the molecular weight between cross-linking points, the higher the cross-linking density, and the higher the number of cross-linking points, the higher the cross-linking density. can improve shielding against

A urethane (meth)acrylate compound generally means a reaction product of an isocyanate compound, a polyol compound and a (meth)acrylate compound, and is a polyfunctional urethane (meth)acrylate having two or more (meth)acryloyloxy groups in the molecule. A compound is preferred. Since the polyfunctional urethane (meth)acrylate compound can form a crosslinked structure, it is advantageous from the viewpoint of improving the function of suppressing the diffusion of the absorption anisotropic dye of the first diffusion prevention layer 35 and the second diffusion prevention layer 36. At the same time, appropriate toughness can be imparted. The number of functional groups of the polyfunctional urethane (meth)acrylate compound is preferably 2 or more and 5 or less.

Examples of epoxy (meth)acrylate compounds include polyfunctional epoxy (meth)acrylate compounds that can be obtained by an addition reaction between polyglycidyl ether and (meth)acrylic acid and have at least two (meth)acryloyloxy groups in the molecule. ) acrylates and the like.
Polyester (meth)acrylate compounds include, for example, compounds having an ester bond and at least two (meth)acryloyl groups (typically (meth)acryloyloxy groups) in the molecule.

When the curable composition contains a radically polymerizable compound, it preferably contains a polyfunctional (meth)acrylate compound as the radically polymerizable compound. In this case, the content of the polyfunctional (meth)acrylate compound may be, for example, 50 parts by mass or more, or may be 60 parts by mass or more, relative to 100 parts by mass of the solid content of the curable composition. It may be 70 parts by mass or more, 100 parts by mass or less, 95 parts by mass or less, or 90 parts by mass or less.

When the curable composition contains a radically polymerizable compound, it preferably contains a polyfunctional (meth)acrylate compound and a polyfunctional urethane (meth)acrylate compound as the radically polymerizable compound. In this case, the content ratio of the polyfunctional (meth)acrylate compound and the urethane (meth)acrylate compound (polyfunctional (meth)acrylate compound: urethane (meth)acrylate compound, mass ratio) is 95:5 to 50:50. It may be from 90:10 to 70:30.

When the curable composition contains a radically polymerizable compound, it preferably contains a radical photopolymerization initiator. A radical photopolymerization initiator initiates a polymerization reaction of a radically polymerizable compound by irradiation with active energy rays such as visible light, ultraviolet rays, X-rays, or electron beams. A photoradical polymerization initiator may be used individually by 1 type, and may use 2 or more types together.

Specific examples of photoradical polymerization initiators include acetophenone, 3-methylacetophenone, benzyldimethylketal, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, 2-methyl-1- Acetophenone initiators such as [4-(methylthio)phenyl]-2-morpholinopropan-1-one and 2-hydroxy-2-methyl-1-phenylpropan-1-one; benzophenone, 4-chlorobenzophenone and 4, Benzophenone initiators such as 4′-diaminobenzophenone; alkylphenone initiators such as 2,2-dimethoxy-1,2-diphenylethan-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone; benzoin propyl ether and benzoin ether-based initiators such as benzoin ethyl ether; thioxanthone-based initiators such as 4-isopropylthioxanthone; acylphosphine oxide-based initiators such as bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide; fluorenone, camphorquinone, benzaldehyde, anthraquinone and the like.

The content of the photoradical polymerization initiator in the curable composition may be 1 part by mass or more, 2 parts by mass or more, or 10 parts by mass with respect to 100 parts by mass of the solid content of the polymerizable compound. It may be less than or equal to 8 parts by mass. When the content of the photoradical polymerization initiator is within the above range, the photoradical polymerization initiator is less likely to remain while sufficiently expressing the polymerization initiation ability and improving the curability, resulting in a decrease in visible light transmittance. etc., can be easily suppressed.

The first anti-diffusion layer 35 and the second anti-diffusion layer 36 formed from the curable composition are formed on the surfaces forming the first anti-diffusion layer 35 and the second anti-diffusion layer 36 (for example, the surfaces of the circularly polarizing plates 30 and 40 It can be formed by applying the curable composition to the linear polarizing layer 31), irradiating it with an active energy ray, and curing the curable composition. The curable composition may contain an organic solvent in order to adjust the viscosity to suit the application method, or may be substantially solvent-free (solvent-free). "Substantially free" means not excluding cases where the solvent is unavoidably mixed.

Any solvent can be used as long as it can dissolve the components constituting the curable composition. Examples include water; methanol, ethanol, ethylene glycol, isopropyl alcohol, propylene glycol, methyl cellosolve, butyl cellosolve, propylene glycol monomethyl ether, and the like Alcohol solvents; ester solvents such as ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, γ-butyrolactone, propylene glycol methyl ether acetate, ethyl lactate; acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, methyl amyl ketone, methyl isobutyl ketone, etc. ketone solvents such as pentane, hexane and heptane; aromatic hydrocarbon solvents such as toluene and xylene; nitrile solvents such as acetonitrile; ether solvents such as tetrahydrofuran and dimethoxyethane; hydrocarbon solvents and the like.
These solvents may be used alone or in combination of two or more.

The curable composition may optionally contain a cationic polymerization accelerator, a photosensitizer, an ion trapping agent, an antioxidant, a chain transfer agent, a tackifier, a thermoplastic resin, a filler, a flow control agent, and a plasticizer. , antifoaming agents, antistatic agents, and leveling agents.

The active energy rays used for curing the curable composition include visible light, ultraviolet rays, X-rays, electron beams, etc., but ultraviolet rays are preferred. Light sources for active energy rays include low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, xenon lamps, halogen lamps, carbon arc lamps, tungsten lamps, gallium lamps, excimer lasers, and a wavelength range of 380 to 440 nm. LED light sources, chemical lamps, black light lamps, microwave excited mercury lamps, metal halide lamps, and the like.

The irradiation intensity of ultraviolet rays is usually 10 mW/cm ² or more and 3000 mW/cm ² or less. It is preferable that the ultraviolet irradiation intensity is in a wavelength range effective for activating the photopolymerization initiator. The irradiation time of ultraviolet rays is usually 0.1 seconds or longer, may be 1 second or longer, may be 5 seconds or longer, may be 10 seconds or longer, and may be 10 minutes or shorter. It may be 5 minutes or less, 3 minutes or less, or 1 minute or less. The cumulative amount of UV light may be 10 mJ/cm ² or more, 50 mJ/cm ² or more, 100 mJ/cm ² or more, or 3000 mJ/cm ² or less. Well, it may be 2000 mJ/cm ² or less, or it may be 1000 mJ/cm ² .

The thicknesses of the first anti-diffusion layer 35 and the second anti-diffusion layer 36 are each independently preferably 5 μm or less, may be 4 μm or less, or may be 3 μm or less. It may be 1 μm or more, 0.3 μm or more, or 0.5 μm or more. When the thicknesses of the first anti-diffusion layer 35 and the second anti-diffusion layer 36 are within the above range, the absorption anisotropic dye in the linear polarizing layer 31 is effectively suppressed from diffusing into other layers. be able to.

(First bonding layer, second bonding layer, third bonding layer, bonding layer)
The 1st bonding layer 25, the 2nd bonding layer 32, the 3rd bonding layer 37, and the bonding layer are adhesive layers or adhesive layers. The pressure-sensitive adhesive layer can be formed using the pressure-sensitive adhesive composition or the active energy ray-curable pressure-sensitive adhesive composition described for the first pressure-sensitive adhesive layer 21 and the second pressure-sensitive adhesive layer 12 . The thickness of the pressure-sensitive adhesive layer can be within the range described for the first pressure-sensitive adhesive layer 21 and the second pressure-sensitive adhesive layer 12 .

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 in which polyvinyl alcohol resin is dissolved or dispersed 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. be done. Adhesion between layers can be improved by using a non-solvent active energy ray-curable adhesive.

The active energy ray-curable adhesive preferably contains either one or both of a cationic polymerizable curable compound and a radically polymerizable curable compound because it exhibits good adhesiveness. The active energy ray-curable adhesive can further contain a cationic polymerization initiator such as a photocationic polymerization initiator or a radical polymerization initiator for initiating the curing reaction of the curable compound.

Examples of cationic polymerizable curable compounds include alicyclic epoxy compounds having an epoxy group bonded to an alicyclic ring, and polyfunctional aliphatic epoxy compounds having two or more epoxy groups and no aromatic ring. , monofunctional epoxy groups having one epoxy group (excluding those contained in alicyclic epoxy compounds), polyfunctional aromatic epoxy compounds having two or more epoxy groups and aromatic rings, etc. compounds; oxetane compounds having one or more oxetane rings in the molecule; and combinations thereof.

Radically polymerizable curable compounds include, for example, (meth)acrylic compounds (compounds having one or more (meth)acryloyloxy groups in the molecule), and other radically polymerizable double bonds. vinyl-based compounds, or combinations thereof.

The active energy ray-curable adhesive can contain a sensitizer such as a photosensitizer as needed. By using a sensitizer, the reactivity is improved, and the mechanical strength and adhesive strength of the adhesive layer can be further improved. A known sensitizer can be appropriately applied. When a sensitizer is blended, the blending amount is preferably in the range of 0.1 to 20 parts by mass with respect to 100 parts by mass as the total amount of the active energy ray-curable adhesive.

Active energy ray-curable adhesives may optionally contain ion trapping agents, antioxidants, chain transfer agents, tackifiers, thermoplastic resins, fillers, flow control agents, plasticizers, antifoaming agents, and antistatic agents. Additives such as agents, leveling agents, solvents and the like can be included.

When an active energy ray-curable adhesive is used, an adhesive layer can be formed by irradiating an active energy ray such as ultraviolet rays, visible light, electron beams, and X-rays to cure the adhesive coating layer. . As the active energy ray, ultraviolet rays are preferable, and as a light source in this case, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a chemical lamp, a black light lamp, a microwave-excited mercury lamp, a metal halide lamp, etc. can be used. can.

The thickness of the adhesive layer may be 0.1 μm or more, 0.5 μm or more, 10 μm or less, or 5 μm or less.

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. "%" and "parts" in Examples and Comparative Examples are "% by mass" and "parts by mass" unless otherwise specified.

[Production of surface protective film (1)]
(Preparation of adhesive composition (1))
Nitrogen gas was introduced into a reactor equipped with a stirrer, a thermometer, a reflux condenser and a nitrogen inlet tube to replace the air in the reactor with nitrogen gas. Then, 93 parts of 2-ethylhexyl acrylate, 5.5 parts of 8-hydroxyoctyl acrylate, 1.5 parts of acrylic acid, and 60 parts of a solvent (ethyl acetate) were added to the reactor. Thereafter, 0.1 part of azobisisobutyronitrile as a polymerization initiator was added dropwise over 2 hours, and reaction was carried out at 65° C. for 6 hours to obtain an acrylic resin solution (1). The acrylic polymer contained in the acrylic resin solution (1) had a weight average molecular weight of about 500,000 in terms of standard polystyrene by gel permeation chromatography.

After adding 2.0 parts of 1-octylpyridinium dodecylbenzenesulfonate as an antistatic agent to 100 parts of the acrylic polymer contained in the acrylic resin solution (1) and stirring, Coronate HX (hexamethylene diisocyanate compound 1.5 parts of an isocyanurate body: manufactured by Tosoh Corporation) were added and mixed with stirring to obtain an adhesive composition (1).

(Preparation of surface protective film (1) with separate film)
After applying the pressure-sensitive adhesive composition (1) on a 15 μm thick separate film made of a polyethylene terephthalate (PET) film coated with a silicone resin, the solvent is removed by drying at 90 ° C., and the thickness after drying is A second adhesive layer of 15 μm was formed. After that, as the first base film, a polyethylene terephthalate (PET) film having a thickness of 75 μm having one surface subjected to antistatic treatment and antifouling treatment was used, and the PET film was subjected to antistatic treatment and antifouling treatment. A surface protection film (1) with a separate film was obtained by laminating the surface on the opposite side of the surface to the second pressure-sensitive adhesive layer. The layer structure of the surface protective film (1) with a separate film was surface protective film (1) (first base film/second pressure-sensitive adhesive layer)/separate film.

[Preparation of surface protective film (2)]
Except for using a polyethylene terephthalate (PET) film having a thickness of 38 μm with antistatic treatment and antifouling treatment on one side as the first base film, the surface protective film with a separate film (1) was prepared. A surface protective film (2) with a separate film was obtained by the same procedure. The layer structure of the surface protective film (2) with a separate film was surface protective film (2) (first base film/second pressure-sensitive adhesive layer)/separate film.

[Production of circularly polarizing plate with anti-diffusion layer]

(Preparation of water-soluble polymer aqueous solution)
A water-soluble polymer composed of the following structural units was obtained according to the following synthesis scheme.

In 400 g of dimethyl sulfoxide, 20 g of polyvinyl alcohol (manufactured by Wako Pure Chemical Industries, Ltd.) having a molecular weight of 1000, 0.55 mg of N,N-dimethyl-4-aminopyridine as a nucleophile, and 4.6 g of triethylamine are dissolved, The temperature was raised to 60° C. while stirring. Thereafter, a solution of 10.5 g of methacrylic anhydride dissolved in 50 g of dimethyl sulfoxide was added dropwise over 1 hour, and the mixture was reacted by heating and stirring at a temperature of 60° C. for 14 hours. After cooling the obtained reaction solution to room temperature, 481 g of methanol was added to the reaction solution and stirred so as to be completely mixed, so that the ratio (mass) of the reaction solution and methanol was adjusted to 1:1. bottom. By gradually adding 1500 mL of acetone into this solution, the water-soluble polymer was crystallized by a crystallization method. The resulting solution containing white crystals was filtered, washed thoroughly with acetone, and then vacuum dried to obtain 20.2 g of a water-soluble polymer. The resulting water-soluble polymer was dissolved in water to prepare a 3 mass % water-soluble polymer aqueous solution.

(Preparation of composition for forming photo-alignment layer)
A composition for forming a photo-alignment layer was obtained by mixing the following components and stirring the resulting mixture at a temperature of 80° C. for 1 hour.
· Photo-alignable polymer [Polymer represented by the following formula described in JP-A-2013-33249 (number average molecular weight: about 28200, Mw / Mn: 1.82)]: 2 parts

・Solvent [o-xylene]: 98 parts

(Preparation of first composition)
A first composition was obtained by mixing the following components and stirring at a temperature of 80° C. for 1 hour.
As the dye having absorption anisotropy, an azo dye represented by the following formula described in Examples of JP-A-2013-101328 was used.
- A polymerizable liquid crystal compound (A1) represented by the following formula: 75 parts

- A polymerizable liquid crystal compound (A2) represented by the following formula: 25 parts

- A dye having absorption anisotropy represented by the following formula (azo dye 1): 2.5 parts

- A dye having absorption anisotropy represented by the following formula (azo dye 2): 2.5 parts

- A dye having absorption anisotropy represented by the following formula (azo dye 3): 2.5 parts

・Polymerization initiator [2-dimethylamino-2-benzyl-1-(4-morpholinophenyl)butan-1-one (Irgacure 369; manufactured by Ciba Specialty Chemicals Co., Ltd.)]: 6 parts ・Leveling agent [poly Acrylate compound (BYK-361N; manufactured by BYK-Chemie)]: 1.2 parts Solvent [o-xylene]: 250 parts

(Preparation of second composition)
A second composition was obtained by mixing each of the following components and stirring at a temperature of 80° C. for 1 hour.
- A polymerizable liquid crystal compound (X1) represented by the following formula: 100 parts

- A polymerizable liquid crystal compound (X2) represented by the following formula: 33 parts

・Polymerization initiator [2-dimethylamino-2-benzyl-1-(4-morpholinophenyl)butan-1-one (Irgacure (registered trademark) 369; manufactured by BASF Japan)]: 8 parts ・Leveling agent [polyacrylate Compound (BYK-361N; manufactured by BYK-Chemie)]: 0.1 parts Reaction additive [LALOMER LR9000; manufactured by BASF Japan]: 6.7 parts Solvent [cyclopentanone]: 546 parts Solvent [N -methylpyrrolidone]: 364 parts

(Preparation of composition for forming alignment layer)
A composition for forming an orientation layer was prepared by adding 2-butoxyethanol to Sanever SE-610 (manufactured by Nissan Chemical Industries, Ltd.), which is a commercially available orientation polymer. The solid content was 1% and the solvent content was 99% with respect to the total amount of the alignment layer-forming composition. The solid content of the oriented polymer was converted from the concentration described in the delivery specification.

(Preparation of third composition)
The following components were mixed, stirred at a temperature of 80° for 1 hour, and then cooled to room temperature to obtain a third composition. The content ratio shown below is the content ratio of each component with respect to the total amount of the third composition.
· A polymerizable liquid crystal compound represented by the following formula [LC242; manufactured by BASF]: 19.2%

· Polymerization initiator [Irgacure 907; manufactured by BASF Japan]: 0.5%
・Leveling agent [BYK361N manufactured by BYK Chemie Japan]: 0.1%
・ Reactive additive [Laromer LR-9000; manufactured by BASF Japan]: 1.1%
・ Solvent [propylene glycol 1-monomethyl ether 2-acetate (PGMEA)]: 79.1%

(Preparation of linear polarizing layer with anti-diffusion layer)
Release polyethylene terephthalate (PET) film ("FF-50" manufactured by Unitika Ltd., single-sided release-treated PET film, substrate thickness: 50 μm) was coated with 3% by mass of the aqueous solution prepared above. A water-soluble polymer aqueous solution was applied using a bar coater and dried at a temperature of 100° C. for 2 minutes to form a 2 μm-thick first diffusion prevention layer comprising a film of a water-soluble polymer.

After plasma treatment was applied to the surface of the first anti-diffusion layer, the composition for forming a photo-alignment layer prepared above was applied using a bar coater to form a coating film. This coating film was dried at a temperature of 100° C. for 2 minutes to remove the solvent and form a dry film. The dry film was irradiated with polarized ultraviolet light at an intensity of 20 mJ/cm ² (313 nm standard) to impart an alignment regulating force to form a first alignment layer having a thickness of 50 nm.

The first composition prepared above was applied onto the first alignment layer using a bar coater to form a coating film. Furthermore, the solvent is removed by drying at a temperature of 110° C. for 2 minutes, and the polymerizable liquid crystal compound is phase-transitioned to a liquid phase, and then cooled to room temperature to phase-transition the polymerizable liquid crystal compound to a smectic liquid crystal state. rice field. Thereafter, the obtained dry film is irradiated with ultraviolet light at 1000 mJ/cm ² (365 nm standard) using a high-pressure mercury lamp to polymerize the polymerizable liquid crystal compound contained in the dry film while maintaining the smectic liquid crystal state. to form a first cured layer having a thickness of 3 μm.

After plasma treatment is applied to the first cured layer, the 3 mass% water-soluble polymer aqueous solution prepared above is applied with a bar coater and dried at a temperature of 100 ° C. for 2 minutes to remove the water-soluble polymer. A second anti-diffusion layer made of a film and having a thickness of 2 μm was formed to obtain a linear polarizing layer with an anti-diffusion layer. The layer structure of the linear polarizing layer with the diffusion prevention layer was release PET film/first diffusion prevention layer/linear polarization layer (first alignment layer/first cured layer)/second diffusion prevention layer.

(Preparation of first retardation layer with substrate layer)
Corona treatment was applied to the surface of a release polyethylene terephthalate (PET) film ("FF-50" manufactured by Unitika Ltd., single-sided release-treated PET film, substrate thickness: 50 μm) opposite to the release-treated surface. provided. On this corona-treated surface, the composition for forming a photo-alignment layer prepared above was applied with a bar coater, dried at a temperature of 120° C. for 2 minutes, and then cooled to room temperature to form a dry film. The dry film was irradiated with polarized ultraviolet light at an intensity of 100 mJ/cm ² (313 nm standard) to form a second alignment layer with a thickness of 100 nm.

The second composition prepared above was applied onto the second alignment layer using a bar coater to form a coating film. Further, after drying by heating at a temperature of 120° C. for 2 minutes, it was cooled to room temperature to obtain a dry film. After that, the dry film is irradiated with ultraviolet rays with an exposure amount of 1000 mJ/cm ² (365 nm standard) using an ultraviolet irradiation device, so that the polymerizable liquid crystal compound is oriented horizontally with respect to the surface of the first retardation layer. A second cured layer having a thickness of 2 μm was formed by curing in an oriented state to obtain a first retardation layer with a substrate layer. The layer structure of the first retardation layer with the substrate layer was release PET film/first retardation layer (second orientation layer/second cured layer).

(Preparation of second retardation layer with substrate layer)
The surface of a cycloolefin polymer (COP) film (ZF-14, manufactured by Nippon Zeon Co., Ltd.) was treated once with a corona treatment apparatus under the conditions of an output of 0.3 kW and a treatment speed of 3 m/min. The alignment layer-forming composition prepared above was applied to the corona-treated surface using a bar coater and dried at a temperature of 90° C. for 1 minute to obtain a third alignment layer. The film thickness of the third alignment layer was measured with a laser microscope and found to be 1 μm.

On the third alignment layer, the third composition prepared above was applied using a bar coater to form a coating film, further dried at a temperature of 90 ° C. for 1 minute, and then irradiated with ultraviolet rays using a high-pressure mercury lamp. By irradiating (in a nitrogen atmosphere, integrated light amount at a wavelength of 365 nm: 1000 mJ/cm ² ), the polymerizable liquid crystal compound is cured in a state perpendicular to the surface of the second retardation layer. A cured layer was formed to obtain a second retardation layer with a substrate layer. The layer structure of the second retardation layer with the substrate layer was COP film/second retardation layer (third orientation layer/third cured layer).

(Preparation of adhesive composition)
After mixing the components shown below, the mixture was defoamed to prepare a cationically polymerizable adhesive layer composition.
The cationic polymerization initiator was blended as a 50% by mass propylene carbonate solution, and its solid content is shown.
· 1,6-hexanediol diglycidyl ether (EX-212L, manufactured by Nagase ChemteX Corporation): 25 parts · 4-hydroxybutyl vinyl ether: 10 parts · Bisphenol F type epoxy resin (EXA-830CRP, DIC Corporation) product): 65 parts Cationic polymerization initiator (CPI-100P, manufactured by San-Apro Co., Ltd., 50% by mass solution): 3 parts

(Preparation of circularly polarizing plate with anti-diffusion layer)
The second bonding layer (manufactured by Lintec Corporation, sensor A pressure-sensitive adhesive layer having a thickness of 5 μm) is laminated so that the angle formed by the absorption axis of the linear polarizing layer and the slow axis of the first retardation layer is 45 °, and the linear polarizing layer and A laminate with the first retardation layer was obtained. The layer structure of this laminate is release PET film/first anti-diffusion layer/linearly polarizing layer (first alignment layer/first cured layer)/second anti-diffusion layer/second bonding layer (adhesive layer) /first retardation layer (second cured layer/second orientation layer)/release PET film.

The surface of the second retardation layer of the second retardation layer with the substrate layer obtained above was subjected to corona treatment. The surface exposed by peeling the release PET film on the first retardation layer side of the laminate (laminate of the linear polarizing layer and the first retardation layer) obtained above and the second retardation with the base layer The corona-treated surface of the layer was laminated through the adhesive composition prepared above, and an exposure amount of 500 mJ/cm ² (365 nm) was applied using an ultraviolet irradiation device (SPOT CURE SP-7, manufactured by Ushio Inc.). standard) was irradiated. As a result, a third bonding layer as an adhesive layer having a thickness of 2 μm was formed from the adhesive composition to obtain a circularly polarizing plate with a diffusion prevention layer. The layer structure of the circularly polarizing plate with an anti-diffusion layer is a release PET film/first anti-diffusion layer/linear polarizing layer (first alignment layer/first cured layer)/second anti-diffusion layer/second bonding layer ( Adhesive layer) / first retardation layer (second cured layer / second alignment layer) / third bonding layer (adhesive layer) / second retardation layer (third cured layer / third alignment layer) / It was a COP film. In the circularly polarizing plate with the anti-diffusion layer, the linearly polarizing layer to the second retardation layer constitute the circularly polarizing plate.

[Preparation of release film with first pressure-sensitive adhesive layer]
(Preparation of adhesive composition (2))
81.8 parts of acetone, 98.4 parts of butyl acrylate, 0.6 parts of acrylic acid, and 1.0 part of 2-hydroxyethyl acrylate were added to a reactor equipped with a condenser, nitrogen inlet, thermometer and stirrer. Part of the mixed solution was charged, and the internal temperature was raised to 55° C. while replacing the air in the apparatus with nitrogen gas to make it oxygen-free. Thereafter, a solution obtained by dissolving 0.14 parts of azobisisobutyronitrile (polymerization initiator) in 10 parts of acetone was added to the whole amount. One hour after the addition of the polymerization initiator, the inner temperature was increased to 54 while continuously adding acetone to the reactor at an addition rate of 17.3 parts/hr so that the concentration of the acrylic resin excluding the monomers was 35%. The temperature was maintained at ~56°C for 12 hours, and finally ethyl acetate was added to adjust the concentration of the acrylic resin to 20% to obtain an acrylic resin solution (2).

Acrylic resin solution (2) 100 parts (nonvolatile content), isocyanate compound (Coronate L, ethyl acetate solution of trimethylolpropane adduct of tolylene diisocyanate (solid content concentration 75%) (manufactured by Tosoh Corporation)) 0.5 part, 0.5 part of a silane compound (KBM-403, 3-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.)), and ethyl acetate is added so that the solid content concentration becomes 10%. Then, a pressure-sensitive adhesive composition (2) was obtained.

(Preparation of release film with first pressure-sensitive adhesive layer)
A release-treated polyethylene terephthalate film (thickness: 38 µm) was used as the release film, and the pressure-sensitive adhesive composition (2) was applied to the release-treated surface using an applicator so that the thickness after drying was 15 µm. applied. The coating layer was dried at a temperature of 100° C. for 1 minute to obtain a release film with a first pressure-sensitive adhesive layer. After that, a release-treated polyethylene terephthalate (PET) film (thickness: 38 μm) was laminated as a release film on the first adhesive layer, and cured for 7 days under conditions of a temperature of 23° C. and a relative humidity of 50% RH. Thus, a release film with a first pressure-sensitive adhesive layer was obtained. The layer structure of the release film with the first pressure-sensitive adhesive layer was release film/first pressure-sensitive adhesive layer/release film.

[Example 1]
A 13 μm thick cycloolefin polymer (COP) film (ZF-14, manufactured by Zeon Corporation) as a transparent resin film, and the exposed surface of the release PET film of the circularly polarizing plate with the diffusion prevention layer obtained above. were each subjected to corona treatment. The corona-treated surfaces were laminated together via the adhesive composition prepared above, and exposed to 500 mJ/cm ² (365 nm standard) using an ultraviolet irradiation device (SPOT CURE SP-7, manufactured by Ushio Inc.). ) was irradiated with ultraviolet rays. As a result, a first bonding layer as an adhesive layer having a thickness of 2 μm was formed from the adhesive composition to obtain a laminate of the transparent resin film and the circularly polarizing plate. The layer structure of this laminate is transparent resin film (COP film) / first bonding layer (adhesive layer) / first diffusion prevention layer / linear polarizing layer (first orientation layer / first cured layer) / second Diffusion prevention layer / second bonding layer (adhesive layer) / first retardation layer (second cured layer / second alignment layer) / third bonding layer (adhesive layer) / second retardation layer (second 3 cured layer/third alignment layer)/COP film.

The surface exposed by peeling the COP film on the second retardation layer side of the laminate (laminate of transparent resin film and circularly polarizing plate) obtained above, and the first pressure-sensitive adhesive layer-attached release film obtained above One of the release films was peeled off and the exposed surface was bonded to obtain a laminate (laminate of transparent resin film, circularly polarizing plate, first pressure-sensitive adhesive layer, and release film). The surface exposed by peeling off the separate film from the surface protective film (1) with the separate film obtained above was adhered to the transparent resin film surface of this laminate to obtain an optical laminate (1). The layer structure of the optical laminate (1) is as follows: surface protective film (1) (first base film/second adhesive layer)/transparent resin film (COP film)/first bonding layer (adhesive layer)/ First diffusion prevention layer / linear polarizing layer (first alignment layer / first cured layer) / second diffusion prevention layer / second bonding layer (adhesive layer) / first retardation layer (second cured layer / second 2 orientation layer)/3rd bonding layer (adhesive layer)/2nd retardation layer (3rd cured layer/3rd orientation layer)/1st adhesive layer/release film.

[Example 2]
An optical laminate (2) was obtained in the same manner as in Example 1, except that the surface protective film (2) with a separate film obtained above was used instead of the surface protective film (1) with a separate film. . The layer structure of the optical laminate (2) is as follows: surface protective film (2) (first base film/second adhesive layer)/transparent resin film (COP film)/first bonding layer (adhesive layer)/ First diffusion prevention layer / linear polarizing layer (first alignment layer / first cured layer) / second diffusion prevention layer / second bonding layer (adhesive layer) / first retardation layer (second cured layer / second 2 orientation layer)/3rd bonding layer (adhesive layer)/2nd retardation layer (3rd cured layer/3rd orientation layer)/1st adhesive layer/release film.

[Example 3]
In the same manner as in Example 1, except that a 20 μm-thick triacetyl cellulose (TAC) film (KC2CT, manufactured by Konica Minolta, Inc.) was used instead of the cycloolefin polymer (COP) film as the transparent resin film. An optical laminate (3) was obtained. The layer structure of the optical laminate (3) is as follows: surface protective film (1) (first base film/second adhesive layer)/transparent resin film (TAC film)/first bonding layer (adhesive layer)/ First diffusion prevention layer / linear polarizing layer (first alignment layer / first cured layer) / second diffusion prevention layer / second bonding layer (adhesive layer) / first retardation layer (second cured layer / second 2 orientation layer)/3rd bonding layer (adhesive layer)/2nd retardation layer (3rd cured layer/3rd orientation layer)/1st adhesive layer/release film.

[Example 4]
In the same manner as in Example 2, except that a 20 μm-thick triacetyl cellulose (TAC) film (KC2CT, manufactured by Konica Minolta, Inc.) was used instead of the cycloolefin polymer (COP) film as the transparent resin film. An optical laminate (4) was obtained. The layer structure of the optical laminate (4) is as follows: surface protective film (2) (first base film/second adhesive layer)/transparent resin film (TAC film)/first bonding layer (adhesive layer)/ First diffusion prevention layer / linear polarizing layer (first alignment layer / first cured layer) / second diffusion prevention layer / second bonding layer (adhesive layer) / first retardation layer (second cured layer / second 2 orientation layer)/3rd bonding layer (adhesive layer)/2nd retardation layer (3rd cured layer/3rd orientation layer)/1st adhesive layer/release film.

[Comparative Example 1]
The surface exposed by peeling off the COP film on the second retardation layer side of the circularly polarizing plate with the diffusion prevention layer obtained above and one release film from the release film with the first pressure-sensitive adhesive layer obtained above. A laminate (laminate of circularly polarizing plate, first pressure-sensitive adhesive layer, and release film) was obtained. The surface exposed by peeling the release PET film on the circularly polarizing plate side of the laminate and the surface exposed by peeling the separate film from the surface protective film (2) with the separate film obtained above are bonded together, An optical laminate (5) was obtained. The layer structure of the optical laminate (5) is as follows: surface protective film (2) (first base film/second adhesive layer)/first anti-diffusion layer/linear polarizing layer (first orientation layer/first cured layer ) / second diffusion prevention layer / second bonding layer (adhesive layer) / first retardation layer (second cured layer / second alignment layer) / third bonding layer (adhesive layer) / second Retardation layer (third cured layer/third orientation layer)/first pressure-sensitive adhesive layer/release film.

[Comparative Example 2]
An optical laminate (6) was obtained in the same manner as in Comparative Example 1, except that the surface protective film (1) with a separate film obtained above was used instead of the surface protective film (2) with a separate film. . The layer structure of the optical laminate (6) is as follows: surface protective film (1) (first base film/second adhesive layer)/first anti-diffusion layer/linear polarizing layer (first orientation layer/first cured layer ) / second diffusion prevention layer / second bonding layer (adhesive layer) / first retardation layer (second cured layer / second alignment layer) / third bonding layer (adhesive layer) / second Retardation layer (third cured layer/third orientation layer)/first pressure-sensitive adhesive layer/release film.

[evaluation]
(Measurement of tensile modulus of first base film)
A rectangular test piece (1) having a length of 100 mm and a width of 25 mm was cut out from the first base film used for the surface protection films (1) and (2). Both ends of the test piece (1) in the long side direction were sandwiched between the upper and lower grips of a tensile tester [AUTOGRAPH AG-1S tester manufactured by Shimadzu Corporation] so that the distance between the grips was 5 cm, and the temperature was 23 ° C. In an environment with a relative humidity of 55%, the test piece is pulled in the long side direction at a tensile speed of 1 mm / min, and the resulting stress - From the slope of the initial straight line in the strain curve, the tensile modulus [MPa] in MD at 23 ° C. Calculated. Table 1 shows the results.

(Measurement of tensile modulus of transparent resin film)
The tensile elastic modulus [MPa] of the transparent resin film was calculated in the same manner as the measurement of the tensile elastic modulus of the first base film, except that the transparent resin film used in Examples was used. Table 1 shows the results.

(Measurement of adhesion strength)
A test piece (2) having a width of 25 mm and a length of about 150 mm was cut out from the optical laminates (1) to (6) obtained in Examples and Comparative Examples. Using a tensile tester [AUTOGRAPH AG-1S tester manufactured by Shimadzu Corporation], one end of the test piece (2) in the length direction was gripped, and the crosshead speed was measured under an environment of a temperature of 23 ° C. and a relative humidity of 60%. (Grip movement speed) 200 mm / min, 90 ° peel test in accordance with JIS K 6854-1: 1999 "Adhesive-Peeling adhesive strength test method-Part 1: 90 degree peel", test piece (2 ), and the peel force when peeling the release film from the test piece (2) were measured. The peeling force when peeling the surface protective film is the adhesion force F1 between the surface protective film and the transparent resin film, and the peeling force when peeling the peeling film is the force between the first adhesive layer and the peeling film. The adhesion force was set to F2. Table 1 shows the results.

(Peeling test of peeling film)
A test piece (3) having a width of 80 mm and a length of about 50 mm was cut out from each of the optical laminates (1) to (6) obtained in Examples and Comparative Examples. The surface protective film side of the test piece (3) was pasted to Corning glass (thickness: 0.4 mm) via an adhesive layer (pressure-sensitive adhesive, 5 μm thick). A release tape (Cellotape (registered trademark) CT-24; manufactured by Nichiban Co., Ltd.) was attached to the release film of the test piece (3) attached to Corning glass. The peeling tape has a width of 24 mm and a length of 80 mm. Mounted on the surface (see Figure 3). This was fixed to the evaluation stage of a high-speed peeling tester (manufactured by Imada Seisakusho Co., Ltd.) using a tape.

Next, the end of the peeling tape opposite to the end attached to the test piece (3) is held by the gripping part of the high-speed peel tester, and the angle ( A 180° peeling test was conducted with a peeling angle of 180° and a peeling speed of 2.4 m/min. The results of this test were evaluated according to the following criteria.
A: The lifting force of the release film was 2 N or less.
B: The lifting force of the release film was over 2N.

(Lamination test)
A test piece (4) of 160 mm×80 mm was cut out from each of the optical laminates (1) to (6) obtained in Examples and Comparative Examples. Using a high-precision precision laminating machine (HALTEC HAL650: manufactured by Sankyo Co., Ltd.), the surface protective film side of the test piece (4) is adhered to the upper sucker side of the high-precision precision laminating machine, and the release film is peeled off. Then, the exposed first pressure-sensitive adhesive layer was laminated to a 75 μm thick polyimide film (Upilex-S 75S; manufactured by Ube Industries) placed on the mesh screen side of a high-precision precision laminator. The laminated body after bonding was taken out, and the presence or absence of traces of suction holes was checked and evaluated according to the following criteria.
a: No marks of suction holes were found on the test piece (4).
b: Traces of suction holes were observed on the test piece (4) or the surface protection film.

1, 2 optical laminate, 10 surface protective film, 11 first base film (base film), 12 second adhesive layer, 15 transparent resin film, 21 first adhesive layer, 23 release film, 25 first Bonding layers 30, 40 Circularly polarizing plate 31 Linear polarizing layer 32 Second bonding layer 33 First retardation layer 35 First diffusion prevention layer (diffusion prevention layer) 36 Second diffusion prevention layer 37 Third bonding layer, 38 second retardation layer, 45 peeling tape, 46 suction stage.

Claims (12)

1. Having a surface protective film, a transparent resin film, a circularly polarizing plate, a first adhesive layer, and a release film in this order,
   The surface protection film is peelable from the transparent resin film,
   The circularly polarizing plate includes, in order from the transparent resin film side, a linear polarizing layer including a first cured layer of a first composition containing a polymerizable liquid crystal compound, and a second composition of a second composition containing a polymerizable liquid crystal compound. Having a first retardation layer including a cured layer,
   The optical layered body, wherein the release film is peelable from the first pressure-sensitive adhesive layer.
2. The distance D from the surface of the surface protective film on the transparent resin film side to the surface of the first adhesive layer on the circularly polarizing plate side is 20 μm or more and 60 μm or less,
   The optical laminate according to claim 1, wherein the transparent resin film has a tensile elastic modulus of 1500 MPa or more and 8000 MPa or less at a temperature of 23°C.
3. The surface protection film has a second adhesive layer and a base film in order from the transparent resin film side,
   The tensile elastic modulus of the base film at a temperature of 23° C. is 2500 MPa or more and 6000 MPa or less,
   The optical laminate according to claim 1 or 2, wherein the base film has a thickness of 30 µm or more and 120 µm or less.
4. The optical laminate according to any one of claims 1 to 3, further comprising a first bonding layer between the transparent resin film and the circularly polarizing plate.
5. The optical laminate according to any one of claims 1 to 4, further comprising a diffusion prevention layer between the transparent resin film and the circularly polarizing plate.
6. The optical laminate according to claim 5, wherein the diffusion prevention layer has a thickness of 5 µm or less.
7. The optical laminate according to any one of claims 1 to 6, wherein the circularly polarizing plate has a second bonding layer that bonds the linear polarizing layer and the first retardation layer.
8. The polymerizable liquid crystal compound contained in the first composition is a polymerizable liquid crystal compound exhibiting a smectic liquid crystal phase,
   The optical laminate according to any one of claims 1 to 7, wherein the first composition further contains a dye having absorption anisotropy.
9. The optical according to any one of claims 1 to 8, wherein the second cured layer is cured in a state in which the polymerizable liquid crystal compound is oriented horizontally with respect to the surface of the first retardation layer. laminate.
10. The circularly polarizing plate further includes a second retardation layer including a third cured layer of a third composition containing a polymerizable liquid crystal compound on the side opposite to the linear polarization layer side of the first retardation layer. The optical laminate according to any one of claims 1 to 9.
11. The optical laminate according to claim 10, wherein the third cured layer is cured with the polymerizable liquid crystal compound oriented in a direction perpendicular to the surface of the second retardation layer.
12. The adhesion force F1 between the surface protective film and the transparent resin film and the adhesion force F2 between the first adhesive layer and the release film satisfy the relationship of the following formula (1). 12. The optical laminate according to any one of 1 to 11.
    |F1-F2|≧0.02 [N/25mm] (1)

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