JP7169160B2 - Liquid crystal layer laminate - Google Patents

Description

The present invention relates to liquid crystal layer laminates, and also to optical laminates and methods for producing these.

Organic EL display devices using organic light-emitting diodes (OLED) are not only capable of being made lighter and thinner than liquid crystal display devices, but also offer high image quality such as a wide viewing angle, fast response speed, and high contrast. Since it can be realized, it is used in various fields such as smartphones, TVs, and digital cameras. In an organic EL display device, it is known to improve the antireflection performance by using a circularly polarizing plate or the like in order to suppress deterioration in visibility due to reflection of external light.

For example, in Patent Documents 1 and 2, as a film having an antireflection function applied to an image display panel such as an organic EL display device, a linear polarizing plate (optical film) is formed of a liquid crystal compound and is interposed with an adhesive layer. A laminate having two laminated retardation layers is disclosed.

JP 2015-230386 A JP 2015-79256 A

The above-described film is used by bonding to an optical display element, and if such a film curls so that the side bonded to the optical display element is concave, so-called reverse curling occurs, the film may Air bubbles may be trapped and wrinkles may occur when the optical display element is attached, and these tend to cause defects such as unevenness to be visually recognized. Since such defects cause defects in the image display panel, it is desired to suppress reverse curling of the film.

An object of the present invention is to provide an optical layered body in which reverse curling is suppressed, a liquid crystal layer layered body used for manufacturing the optical layered body, and methods for manufacturing these.

[1] A method for manufacturing a liquid crystal layer laminate in which at least a first liquid crystal layer, a first adhesive layer, and a second liquid crystal layer are laminated in this order,
preparing a first liquid crystal layer with a base material layer, the first liquid crystal layer having a first base material layer and the first liquid crystal layer formed by polymerizing a polymerizable liquid crystal compound on the first base material layer;
preparing a second liquid crystal layer with a base layer, the second liquid crystal layer having a second base layer and the second liquid crystal layer formed by polymerizing a polymerizable liquid crystal compound on the second base layer;
laminating the second liquid crystal layer with the second base layer on the side of the second liquid crystal layer with the first liquid crystal layer with the base layer on the first liquid crystal layer side of the first liquid crystal layer with the base layer via the first adhesive layer; , including
The first adhesive layer is an adhesive cured layer made of a cured product of a curable adhesive,
the absolute value of the curl amount of the first liquid crystal layer is within 20 mm;
The manufacturing method of the liquid crystal layer laminate, wherein the absolute value of the amount of curl of the second liquid crystal layer is within 20 mm.
[2] The first adhesive layer has a storage elastic modulus of E [Pa] at a temperature of 30° C. and a thickness of t [m], where the following formula (1):
3000≦E×t≦15000 (1)
The method for producing a liquid crystal layer laminate according to [1], which satisfies the relationship:
[3] The method for producing a liquid crystal layer laminate according to [1] or [2], further comprising a step of peeling off the first base material layer after the step of laminating.
[4] A liquid crystal layer laminate in which at least a first liquid crystal layer, a first adhesive layer, and a second liquid crystal layer are laminated in this order,
The first liquid crystal layer and the second liquid crystal layer are cured layers of a polymerizable liquid crystal compound,
The first adhesive layer is an adhesive cured layer made of a cured product of a curable adhesive,
the absolute value of the curl amount of the first liquid crystal layer is within 20 mm;
The liquid crystal layer laminate, wherein the absolute value of the amount of curl of the second liquid crystal layer is within 20 mm.
[5] The first adhesive layer has a storage elastic modulus of E [Pa] at a temperature of 30° C. and a thickness of t [m], where the following formula (1):
3000≦E×t≦15000 (1)
The liquid crystal layer laminate according to [4], which satisfies the relationship:
[6] The liquid crystal layer laminate according to [4] or [5], further comprising a second substrate layer on the side of the second liquid crystal layer opposite to the first adhesive layer.
[7] The liquid crystal layer laminate according to [6], further comprising a first substrate layer on the side of the first liquid crystal layer opposite to the first adhesive layer.
[8] A method for producing an optical laminate in which at least an optical film, a second adhesive layer, a first liquid crystal layer, a first adhesive layer, and a second liquid crystal layer are laminated in this order,
The first exposed surface side exposed by peeling the first substrate layer from the liquid crystal layer laminate produced by the method for producing a liquid crystal layer laminate according to [3], and the liquid crystal layer laminate according to [7]. A second adhesive layer and an optical film are provided on the first exposed surface side exposed by peeling the first base layer from the body, or on the first liquid crystal layer side of the liquid crystal layer laminate described in [6]. A method for manufacturing an optical laminate, including the step of laminating in this order.
[9] The method for producing an optical laminate according to [8], further comprising the step of peeling off the second substrate layer after the step of laminating the second adhesive layer and the optical film in this order.
[10] Further, a step of preparing an adhesive layer with a release layer in which an adhesive layer and a release layer are laminated;
The optical laminate according to [9], comprising the step of laminating the adhesive layer side of the adhesive layer with a release layer on the second exposed surface side exposed by peeling the second base layer. body manufacturing method.
[11] The method for producing an optical laminate according to [10], further comprising a step of peeling off the release layer after the step of laminating the pressure-sensitive adhesive layer side of the pressure-sensitive adhesive layer with a release layer.
[12] The method for producing an optical laminate according to any one of [8] to [11], wherein the optical film includes a polarizing plate.
[13] An optical laminate in which at least an optical film, a second adhesive layer, a first liquid crystal layer, a first adhesive layer, and a second liquid crystal layer are laminated in this order,
The first liquid crystal layer and the second liquid crystal layer are cured layers of a polymerizable liquid crystal compound,
The first adhesive layer is an adhesive cured layer made of a cured product of a curable adhesive,
the absolute value of the curl amount of the first liquid crystal layer is within 20 mm;
The optical layered body, wherein the absolute value of the amount of curl of the second liquid crystal layer is within 20 mm.
[14] When the storage elastic modulus of the first adhesive layer at a temperature of 30°C is E [Pa] and the thickness is t [m], the following formula (1):
3000≦E×t≦15000 (1)
The optical layered product according to [13], which satisfies the relationship:
[15] The optical laminate according to [13] or [14], further comprising a second substrate layer on the side of the second liquid crystal layer opposite to the first adhesive layer.
[16] The optical layered body according to [13] or [14], further comprising an adhesive layer on the side of the second liquid crystal layer opposite to the first adhesive layer.
[17] The optical layered body according to [16], further comprising a release layer on the side of the pressure-sensitive adhesive layer opposite to the second liquid crystal layer.
[18] The optical laminate according to any one of [13] to [17], wherein the optical film includes a polarizing plate.

According to the present invention, it is possible to manufacture an optical layered body in which reverse curling is suppressed.

1(a) to 1(d) are schematic cross-sectional views schematically showing an example of the manufacturing process of the liquid crystal layer laminate of the present invention. 2(a) and 2(b) are schematic cross-sectional views schematically showing the continuation of the manufacturing process of the liquid crystal layer laminate shown in FIG. 1. FIG. (a) to (c) are schematic cross-sectional views schematically showing an example of the manufacturing process of the optical layered body of the present invention. 4A and 4B are schematic cross-sectional views schematically showing the continuation of the manufacturing process of the optical layered body shown in FIG. 3; FIG. 5 is a schematic cross-sectional view schematically showing a continuation of the manufacturing process of the optical layered body shown in FIG. 4; FIG. 6A and 6B are schematic cross-sectional views schematically showing the continuation of the manufacturing process of the optical layered body shown in FIG. 5; FIG.

Preferred embodiments of the optical layered product, the liquid crystal layer layered product, and the production method thereof according to the present invention will now be described with reference to the drawings. 1 and 2 are schematic cross-sectional views schematically showing an example of the manufacturing steps of the method for manufacturing the liquid crystal layer laminate of the present embodiment, and FIGS. It is a schematic sectional drawing which shows typically an example of the manufacturing process of a method. In the figure, W represents the width direction.

(Optical laminate)
As shown in FIGS. 4 and 6, the optical laminate of the present embodiment includes at least the optical film 60, the second adhesive layer 32, the first liquid crystal layer 12, the first adhesive layer 31, and the second liquid crystal layer 22. They are stacked in order. Here, the first adhesive layer is an adhesive cured layer made of a cured product of a curable adhesive. The first liquid crystal layer 12 and the second liquid crystal layer 22 are cured layers of a polymerizable liquid crystal compound, and the first liquid crystal layer 12 is formed by polymerizing the polymerizable liquid crystal compound on the first substrate layer 11. The second liquid crystal layer 22 can be formed by polymerizing a polymerizable liquid crystal compound on the second substrate layer 21 . In the optical laminate, the absolute value of the curl amount of the first liquid crystal layer is within 20 mm, and the absolute value of the curl amount of the second liquid crystal layer is within 20 mm.

In this specification, the amount of curl of the first liquid crystal layer 12 and the second liquid crystal layer 22 is a rectangular shape with a long side length of 150 mm and a short side length of 50 mm, and the long side is TD of the optical laminate. In the first liquid crystal layer or the second liquid crystal layer cut out so as to form an angle of 45 degrees with the direction, on the diagonal whose extending direction is relatively close to the direction parallel to the TD direction of the optical laminate It is used to evaluate the curl that occurs at the center, and is calculated according to the procedure described in the examples below.

The amount of curling of the first liquid crystal layer 12 and the second liquid crystal layer 22 depends on the type of polymerizable liquid crystal compound used to form the first liquid crystal layer 12 and the second liquid crystal layer 22, the degree of polymerization (hardening degree) of the polymerizable liquid crystal compound, ), and can be adjusted depending on the type of additive contained in the liquid crystal layer-forming composition. The degree of polymerization of the polymerizable liquid crystal compound depends on the types and amounts of polymerization initiators, reactive additives, polymerization inhibitors, etc. contained in the composition for forming the liquid crystal layer, and irradiation when the polymerizable liquid crystal compound is polymerized and cured. It can be adjusted by the irradiation intensity and irradiation time (irradiation amount) of the active energy ray. The absolute values of the curl amounts of the first liquid crystal layer 12 and the second liquid crystal layer 22 are each independently preferably 15 mm or less, preferably 12 mm or less, preferably 9 mm or less, and 0 mm. It may be 1 mm or more, or it may be 3 mm or more. The smaller the absolute value of the curl amount, the more it is possible to suppress the deformation in which the second liquid crystal layer 22 side is bent in a bow shape (hereinafter sometimes referred to as “reverse curl”). It is easy to make a (flat) state.

As shown in FIG. 6B, a layer structure having an optical film 60, a second adhesive layer 32, a first liquid crystal layer 12, a first adhesive layer 31, a second liquid crystal layer 22, and an adhesive layer 33 in this order. The adhesive layer-attached optical laminate 73 (optical laminate) may be used by bonding the adhesive layer 33 to an optical display element. In this case, if the optical layered body 73 with the adhesive layer is reversely curled (deformed into a bow with the adhesive layer 33 side facing inward), air bubbles may be mixed in or wrinkles may occur when the optical layered body 73 is attached to the optical display element. There is a tendency for problems such as unevenness to occur due to the occurrence of unevenness. However, since the absolute value of the curl amount of the first liquid crystal layer 12 and the second liquid crystal layer 22 of the adhesive layer-attached optical layered body 73 is 20 mm or less, the occurrence of reverse curl can be suppressed, and the optical display element It is possible to suppress the above-described problems that may occur when laminating to.

The reason for this is presumed as follows. The first liquid crystal layer 12 and the second liquid crystal layer 22 (hereinafter, sometimes collectively referred to as "liquid crystal layer") of the optical layered body 73 with an adhesive layer are the first base material layer 11 and the second liquid crystal layer 22, respectively. A composition for forming a liquid crystal layer containing a polymerizable liquid crystal compound is applied onto the base material layer 21 (hereinafter, both may be collectively referred to as a "base material layer"), dried, and exposed to active energy rays such as ultraviolet rays. It can be formed by polymerizing and curing a polymerizable liquid crystal compound by irradiation. In the liquid crystal layer formed through the steps of coating, drying, polymerization, curing, etc. described above, shrinkage stress generated during drying of the applied liquid crystal layer forming composition and curing accompanying polymerization of the polymerizable liquid crystal compound is applied. presumed to remain. When the liquid crystal layer is present on the substrate layer, the shrinkage stress is suppressed by the substrate layer. be done. Therefore, when the base material layer is peeled off, the shrinkage stress of the liquid crystal layer is released, and the liquid crystal layer is affected by the released shrinkage stress to cause the adhesive layer-attached optical layered body 73 to curl. considered to be deformed.

Like the adhesive layer-attached optical layered body 73 shown in FIG. 6(b), the first liquid crystal layer 12 and the second liquid crystal layer 12 and the second liquid crystal are applied only to one side of the optical film 60 exhibiting relatively high rigidity via an adhesive layer. In the structure in which the layer 22 is laminated, the shrinkage stress remaining in the liquid crystal layer acts to cause the optical laminated body 73 with the adhesive layer to curl with the liquid crystal layer side facing inward, which tends to cause reverse curling. be.

Therefore, in the adhesive layer-attached optical layered body 73 of the present embodiment, the first liquid crystal layer 12 and the second liquid crystal layer 22 each having an absolute value of curl amount of 20 mm or less are used. Thus, even when the contraction stress of the first liquid crystal layer 12 and the second liquid crystal layer 22 is released by peeling off the first base layer 11 and the second base layer 21, these liquid crystal layers are deformed. It is presumed that this can be suppressed. As a result, it is possible to suppress the occurrence of reverse curling in the optical layered body 73 with an adhesive layer.

When the storage elastic modulus of the first adhesive layer 31 at a temperature of 30° C. is E [Pa] and the thickness is t [m], the following formula (1):
3000≦E×t≦15000 (1)
It is preferable to have a rigidity that satisfies the relationship of

The value of E × t in the above formula (1) is more preferably 3500 [Pa m] or more, further preferably 4000 [Pa m] or more, and 4300 [Pa m] or more. It is more preferably 14000 [Pa·m] or less, and even more preferably 13000 [Pa·m] or less. When the value of E×t is less than 3000 [Pa·s], it tends to be difficult to suppress the occurrence of reverse curling of the optical layered body, and when it exceeds 15000 [Pa·s], the optical layered body becomes an optical film. The deformation (hereinafter sometimes referred to as "positive curl") of bowing with the 60 side inside tends to progress too much, making it difficult for the optical layered body to be in a flat state. It can get difficult.

The storage elastic modulus E of the first adhesive layer 31 at 30° C. can be adjusted depending on the type of adhesive or adhesive used to form the first adhesive layer 31 . The storage elastic modulus E of the first adhesive layer 31 at 30° C. is preferably 100 MPa or more, more preferably 1000 MPa or more, may be 1500 MPa or more, or may be 2000 MPa or more. The storage elastic modulus E of the first adhesive layer 31 at 30° C. is usually 10000 MPa or less, preferably 8000 MPa or less, and more preferably 5000 MPa or less.

The thickness t of the first adhesive layer 31 may be adjusted according to the storage elastic modulus E of the first adhesive layer 31 at 30°C. It is more preferably 2.5 μm or more, and may be 3 μm or more, or may be 3.5 μm or more.

As shown in FIG. 6B, the optical laminate of the present embodiment includes an optical film 60, a second adhesive layer 32, a first liquid crystal layer 12, a first adhesive layer 31, a second liquid crystal layer 22, and an adhesive. The adhesive layer-attached optical layered body 73 having a layer structure of the layer 33 may be used, and as shown in FIG. The release layer-attached optical layered body 72 (optical layered body) may have a second release layer 53 for protecting the adhesive layer 33 on the opposite side. Further, as shown in FIG. 4A, the optical laminate of this embodiment includes an optical film 60, a second adhesive layer 32, a first liquid crystal layer 12, a first adhesive layer 31, a second liquid crystal layer 22, and The substrate layer-attached optical layered body 70 (optical layered body) may have the second substrate layer 21 in this order, and as shown in FIG. It may be an optical layered body 71 (optical layered body) from which the substrate layer 21 has been peeled off. Each of these optical layered bodies (hereinafter collectively referred to as "optical layered body") is in the form of being used by bonding to an optical display element (for example, an optical layered body 73 with a pressure-sensitive adhesive layer). In some cases, the occurrence of reverse curling can be suppressed, and the above-described problems that may occur during lamination to an optical display element can be suppressed.

(Liquid crystal layer laminate)
The liquid crystal layer laminate of this embodiment can be used for manufacturing an optical laminate, and as shown in FIG. Layers 22 are laminated in this order. As described above, the first liquid crystal layer 12 and the second liquid crystal layer 22 are cured layers of a polymerizable liquid crystal compound, and the absolute value of the curl amount is 20 mm or less. Moreover, as described above, the first adhesive layer 31 is an adhesive cured layer made of a cured product of a curable adhesive, and preferably satisfies the relationship of formula (1) described above. Descriptions of the first liquid crystal layer 12, the second liquid crystal layer 22, and the first adhesive layer 31 are the same as described above, so the description thereof will be omitted.

As shown in FIG. 2A, the liquid crystal layer laminate of the present embodiment includes a first substrate layer 11, a first liquid crystal layer 12, a first adhesive layer 31, a second liquid crystal layer 22, and a second substrate. It may be a liquid crystal layer laminate 40 with double-sided substrate layers (liquid crystal layer laminate) having a layer structure of layers 21, and one side obtained by peeling the first substrate layer 11 from the liquid crystal layer laminate 40 with double-sided substrate layers. It may be a liquid crystal layer laminate 41 (liquid crystal layer laminate) (FIG. 2(b)) with a base material layer. As shown in FIG. 2B, the liquid crystal layer laminate 41 with a single-sided substrate layer has a layer structure of a first liquid crystal layer 12, a first adhesive layer 31, a second liquid crystal layer 22, and a second substrate layer 21. have By manufacturing an optical laminate using each of these liquid crystal layer laminates (hereinafter collectively referred to as a "liquid crystal layer laminate"), it is possible to suppress the occurrence of reverse curling and improve optical performance. It is possible to manufacture an optical layered body capable of suppressing the above-described problems that may occur during lamination to a display element.

(Method for producing liquid crystal layer laminate and method for producing optical laminate)
A method for manufacturing a liquid crystal layer laminate and a method for manufacturing an optical laminate according to the present embodiment will be described below with reference to FIGS. 1 to 6. FIG. In the method for manufacturing an optical layered body, for example, an optical layered body can be manufactured using the liquid crystal layer layered body 41 with a single-sided substrate layer. In the following, an example in which the second adhesive layer 32 is an adhesive layer formed of an adhesive in the adhesive layer-attached optical layered body 73 shown in FIG. 6B will be described.

(Manufacturing method of liquid crystal layer laminate)
The manufacturing method of the liquid crystal layer laminate 41 with a single-sided base material layer shown in FIG. 2(b) includes the first liquid crystal layer 10 with a base material layer shown in FIG. and a step of preparing a second liquid crystal layer 20 . The first liquid crystal layer 10 with a substrate layer has a first substrate layer 11 and a first liquid crystal layer 12 formed by polymerizing a polymerizable liquid crystal compound on the first substrate layer 11. 1 base material layer 11 is formed so as to be detachable from first liquid crystal layer 12 . The second liquid crystal layer 20 with base material layer has a second base material layer 21 and a second liquid crystal layer 22 formed by polymerizing a polymerizable liquid crystal compound on the second base material layer 21. A second base material layer 21 is formed so as to be detachable from the second liquid crystal layer 22 .

In the step of preparing the first liquid crystal layer 10 with a base layer, a composition for forming a liquid crystal layer containing a polymerizable liquid crystal compound is applied onto the first base layer 11, dried, and irradiated with an active energy ray such as ultraviolet rays. may include a step of forming the first liquid crystal layer 12 by polymerizing and curing the polymerizable liquid crystal compound. Similarly, the step of preparing the second liquid crystal layer 20 with a substrate layer includes coating the second substrate layer 21 with a composition for forming a liquid crystal layer containing a polymerizable liquid crystal compound, drying it, and applying an active agent such as ultraviolet rays. A step of forming the second liquid crystal layer 22 by polymerizing and curing the polymerizable liquid crystal compound by irradiating the energy beam may be included.

Next, an adhesive composition layer containing an adhesive composition for forming a first adhesive layer 31, which is an adhesive cured layer, on the surface of the second liquid crystal layer 20 with a base layer on the side of the second liquid crystal layer 22. 31a is formed. Through this process, a second liquid crystal layer 25 with a composition layer can be obtained (FIG. 1(c)). As shown in FIG. 1(c), the second liquid crystal layer 25 with a composition layer is formed by laminating an adhesive composition layer 31a, a second liquid crystal layer 22, and a second substrate layer 21 in this order. . The step of forming the adhesive composition layer 31a may include a step of applying an adhesive composition to the surface of the second liquid crystal layer 20 with the substrate layer on the second liquid crystal layer 22 side.

After laminating the first liquid crystal layer 12 side of the first liquid crystal layer 10 with a base layer on the adhesive composition layer 31a side of the obtained second liquid crystal layer 25 with a composition layer (FIG. 1(d)), A first adhesive layer 31 is formed from the adhesive composition layer 31a to obtain a liquid crystal layer laminate 40 with double-sided substrate layers (FIG. 2(a)). The method of forming the adhesive composition layer 31a can be appropriately selected according to the type of the adhesive composition, and examples thereof include active energy ray irradiation, heat treatment, addition of a curing agent, and the like. . As shown in FIG. 2A, the liquid crystal layer laminate 40 with double-sided substrate layers includes a first substrate layer 11, a first liquid crystal layer 12, a first adhesive layer 31, a second liquid crystal layer 22, and a second liquid crystal layer 22. The base material layers 21 are laminated in this order.

From the liquid crystal layer laminate 40 with double-sided substrate layers shown in FIG. Then, a liquid crystal layer laminate 41 with a single-sided substrate layer is obtained in which the first liquid crystal layer 12, the first adhesive layer 31, the second liquid crystal layer 22, and the second substrate layer 21 are laminated in this order. The first adhesive layer 31 in the liquid crystal layer laminate 40 with a double-sided substrate layer shown in FIG. 2A and the liquid crystal layer laminate 41 with a single-sided substrate layer shown in FIG. It is preferable that the cured adhesive layer is a cured product and has a rigidity that satisfies the relationship of the above formula (1). Also, the absolute value of the curl amount of both the first liquid crystal layer 12 and the second liquid crystal layer 22 is 20 mm or less.

(Method for manufacturing optical laminate)
In the method for manufacturing the adhesive layer-attached optical layered body 73 shown in FIG. 6B, first, the second adhesive layer 32, which is an adhesive layer made of an adhesive, was formed on the first release layer 51. A step of preparing a second adhesive layer 50 with a release layer is performed (FIG. 3(a)). The step of preparing the second adhesive layer 50 with a release layer may include a step of applying a pressure-sensitive adhesive composition on the first release layer 51 and drying it to form the second adhesive layer 32 . Further, if necessary, a step of covering the surface of the second adhesive layer 32 opposite to the first peeling layer 51 with another peeling layer may be provided. The second adhesive layer 32 of the prepared second adhesive layer 50 with a release layer and the optical film 60 are laminated (FIG. 3(b)), the first release layer 51 is peeled off, and the optical film with the second adhesive layer is obtained. 61 is obtained (FIG. 3(c)). The optical film 61 with the second adhesive layer is obtained by laminating the optical film 60 and the second adhesive layer 32, as shown in FIG. 3(c).

After that, the second adhesive layer 32 of the optical film 61 with the second adhesive layer and the first base layer 11 of the liquid crystal layer laminate 41 with the single-sided base layer exposed by peeling off the first base layer 11 (FIG. 2(b)). 1 liquid crystal layer 12 (first exposed surface) is bonded to obtain an optical layered body 70 (optical layered body) with a substrate layer (FIG. 4A). The single-sided substrate layer-attached liquid crystal layer laminate 41 may have the structure shown in FIG. As shown in FIG. 4( a ), the optical layered body 70 with a base material layer includes an optical film 60 , a second adhesive layer 32 , a first liquid crystal layer 12 , a first adhesive layer 31 , a second liquid crystal layer 22 , and a second liquid crystal layer 22 . Two base material layers 21 are laminated in this order. By peeling the second base layer 21 from the base layer-attached optical layered body 70, the base layer-separated optical layered body 71 can be obtained (FIG. 4(b)).

Subsequently, a step of preparing a release layer-attached adhesive layer 58 in which the second release layer 53 and the adhesive layer 33 are laminated is performed (FIG. 5). The step of preparing the adhesive layer 58 with a release layer may include a step of applying an adhesive composition on the second release layer 53 and drying it to form the adhesive layer 33 . Moreover, if necessary, a step of coating the surface of the pressure-sensitive adhesive layer 33 opposite to the second release layer 53 with another release layer may be provided.

The pressure-sensitive adhesive layer 33 side of the prepared pressure-sensitive adhesive layer 58 with a release layer and the second liquid crystal layer 22 (second exposed surface ) side is laminated to obtain an optical layered body 72 with a release layer (FIG. 6A). As shown in FIG. 6A, the release layer-attached optical laminate 72 includes an optical film 60, a second adhesive layer 32, a first liquid crystal layer 12, a first adhesive layer 31, a second liquid crystal layer 22, and an adhesive layer. 33 and the second release layer 53 are laminated in this order. By peeling off the second release layer 53 from the release layer-attached optical layered body 72, the adhesive layer-attached optical layered body 73 shown in FIG. 6(b) can be obtained. The obtained optical layered body 73 with an adhesive layer can be used as an image display panel by laminating the adhesive layer 33 and an optical display element.

In the method for producing the liquid crystal layer laminate (FIG. 2) and the method for producing the optical laminate (FIGS. 4 and 6) described above, the polymerizable liquid crystal compound is formed on the first substrate layer 11 and the second substrate layer 21. By polymerizing and curing, the first liquid crystal layer 12 and the second liquid crystal layer 22 are formed. Therefore, when the first substrate layer 11 is peeled off from the liquid crystal layer laminate 40 with double-sided substrate layers shown in FIG. When the second base material layer 21 is peeled off, it is considered that the shrinkage stress remaining in the first liquid crystal layer 12 and the second liquid crystal layer 22 is released when the polymerizable liquid crystal compound is hardened due to polymerization. In this embodiment, since the absolute value of the curl amount of the first liquid crystal layer 12 and the second liquid crystal layer 22 is 20 mm or less, the contraction stress is released by peeling off the first base layer 11 and the second base layer 21. However, the amount of deformation of the first liquid crystal layer 12 and the second liquid crystal layer 22 is considered to be small. Therefore, even if the contraction stress of the first liquid crystal layer 12 and the second liquid crystal layer 22 is released, the optical layered body 71 (FIG. 4(b)) after peeling of the base layer is difficult to deform. This prevents the occurrence of reverse curling in the optical layered body 71 with the substrate layer peeled, the optical layered body 72 with the peeling layer, and the optical layered body 73 with the pressure-sensitive adhesive layer shown in FIGS. can be suppressed.

In addition, the first adhesive layer 31 is an adhesive cured layer and has a rigidity that satisfies the relationship of the above formula (1). In the optical layered body 73 with the agent layer, it is possible to prevent the optical layered body from being excessively curled to be in a flat state.

Note that the first liquid crystal layer 10 with a base layer, the second liquid crystal layer 20 with a base layer, and the second adhesive layer 50 with a peeling layer are used for manufacturing the liquid crystal layer laminate and the optical laminate in this embodiment. , the pressure-sensitive adhesive layer 58 with a peeling layer, the optical film 60, the optical film 61 with a second adhesive layer, etc., are all preferably long film-like materials, and these are continuously transported. It is preferable to perform each step. The width direction W is usually a direction (TD direction) perpendicular to the length direction (conveyance direction, MD direction) of the film.

(Modification)
The liquid crystal layer laminate, the optical laminate, and the manufacturing method thereof according to the present embodiment may be modified as in the modifications shown below. Further, the above-described embodiment and modifications shown below may be combined arbitrarily.

(Modification 1)
Although the case where the second adhesive layer 32 of the optical layered body is an adhesive layer has been described above, the present invention is not limited to this. For example, the second adhesive layer 32 may be a cured adhesive layer made of a cured curable adhesive. In this case, instead of forming the second adhesive layer on the first peeling layer 51, the optical film 60 and the first substrate layer 11 of the liquid crystal layer laminate 41 with a single-sided substrate layer are peeled off and exposed. An adhesive composition layer containing an adhesive composition may be formed on at least one of the first liquid crystal layer 12 (first exposed surface).

(Modification 2)
In the above, the second liquid crystal layer 25 with a composition layer, in which the adhesive composition layer 31a is provided on the second liquid crystal layer 22 side of the second liquid crystal layer 20 with a base layer (FIG. 1(c)), is used. Although the case where the first liquid crystal layer 12 of the first liquid crystal layer 10 with the base layer is laminated on the agent composition layer 31a has been described as an example, the first liquid crystal layer 12 of the first liquid crystal layer 10 with the base layer has been described. and the second liquid crystal layer 22 of the second liquid crystal layer 20 with the base layer are laminated via the first adhesive layer 31 to obtain a liquid crystal layer laminate 40 with double-sided base layers (FIG. 2A). If possible, it is not limited to this. For example, an adhesive composition layer 31a is provided on the side of the first liquid crystal layer 12 of the first liquid crystal layer 10 with a base layer, and the second liquid crystal of the second liquid crystal layer 20 with a base layer is provided on the adhesive composition layer 31a. After laminating the layer 22 side, the first adhesive layer 31 may be formed by curing the adhesive composition layer 31a. Further, the adhesive composition layer 31a is formed on both the first liquid crystal layer 12 side of the first liquid crystal layer 10 with the base layer and the second liquid crystal layer 22 side of the second liquid crystal layer 20 with the base layer. can be

(Modification 3)
In the above, using the second adhesive layer 50 with a peeling layer shown in FIG. ), the case of laminating the second adhesive layer 32 of the optical film 61 with the second adhesive layer and the first liquid crystal layer 12 of the liquid crystal layer laminate 41 with a single-sided base layer was explained as an example. Laminating an optical film 60 on the exposed surface (first liquid crystal layer 12) of the liquid crystal layer laminate 41 with a single-sided base layer exposed by peeling off the first base layer 11, with the second adhesive layer 32 interposed therebetween. If possible, it is not limited to this. For example, using the second adhesive layer 50 with a peeling layer shown in FIG. Alternatively, a liquid crystal layer laminate with a second adhesive layer may be obtained, and the optical film 60 may be laminated on the second adhesive layer 32 . In this case, the liquid crystal layer laminate with the second adhesive layer has the second adhesive layer 32, the first liquid crystal layer 12, the first adhesive layer 31, the second liquid crystal layer 22, and the second substrate layer 21 in this order. The first peeling layer 51 may be provided on the surface of the second adhesive layer 32 opposite to the first liquid crystal layer 12 .

Although the embodiments of the present invention and their modifications have been described above, the present invention is not limited to these embodiments and their modifications. can also be implemented. The details of each member used in the embodiment will be described below.

(optical film)
The optical film is a film containing a thermoplastic resin film made of a thermoplastic resin, and is a film having an optical function. A protective film-attached polarizing plate, a reflective film, a transflective reflective film, a brightness enhancement film, an optically-compensatory film, a film with an antiglare function, etc., in which a protective film is laminated on at least one side of the film. The optical film may have a single-layer structure, or may be a laminated optical film having a multi-layer structure of two or more layers.

It is considered that the reverse curl generated in the optical layered body is more likely to be affected by the release of shrinkage stress by the liquid crystal layer as the thickness and rigidity of the optical film included in the optical layered body are smaller. In addition, the greater the thickness and rigidity of the base material layer, the greater the shrinkage stress remaining in the liquid crystal layer. Therefore, the thickness of the optical film is preferably 2 μm or more and 500 μm or less. The thickness of the optical film may be 10 μm or more, 350 μm or less, 200 μm or less, or 150 μm or less.

(Polarizer)
Any appropriate polarizer can be adopted as the polarizer. As used herein, the term “polarizer” refers to a linear polarizer that has the property of transmitting linearly polarized light having a plane of vibration perpendicular to the absorption axis when unpolarized light is incident thereon. For example, the resin film forming the polarizer may be a single-layer resin film or a laminated film of two or more layers. The polarizer may be a cured film obtained by aligning a dichroic dye in a polymerizable liquid crystal compound and polymerizing the polymerizable liquid crystal compound.

Specific examples of polarizers composed of single-layer resin films include polyvinyl alcohol (hereinafter sometimes abbreviated as "PVA") films, partially formalized PVA films, and ethylene/vinyl acetate copolymers. Hydrophilic polymer films such as partially saponified films that have been dyed with dichroic substances such as iodine and dichroic dyes and stretched, dehydrated PVA and dehydrated polyvinyl chloride Polyene-based oriented films such as those treated with hydrochloric acid can be used. A polarizer obtained by dyeing a PVA-based film with iodine and uniaxially stretching the film is preferably used because of its excellent optical properties.

Specific examples of polarizers composed of single-layer resin films include polyvinyl alcohol (hereinafter sometimes abbreviated as "PVA") films, partially formalized PVA films, and ethylene/vinyl acetate copolymers. Hydrophilic polymer films such as partially saponified films that have been dyed with dichroic substances such as iodine and dichroic dyes and stretched, dehydrated PVA and dehydrated polyvinyl chloride Polyene-based oriented films such as those treated with hydrochloric acid can be used. A polarizer obtained by dyeing a PVA-based film with iodine and uniaxially stretching the film is preferably used because of its excellent optical properties.

The degree of saponification of the polyvinyl alcohol resin is usually about 85 to 100 mol %, preferably 98 mol % or more. The polyvinyl alcohol-based resin may be modified, and for example, polyvinyl formal or polyvinyl acetal modified with aldehydes may be used. The degree of polymerization of the polyvinyl alcohol resin is generally about 1,000 to 10,000, preferably about 1,500 to 5,000.

The degree of saponification of the polyvinyl alcohol resin is usually about 85 to 100 mol %, preferably 98 mol % or more. The polyvinyl alcohol-based resin may be modified, and for example, polyvinyl formal or polyvinyl acetal modified with aldehydes may be used. The degree of polymerization of the polyvinyl alcohol resin is generally about 1,000 to 10,000, preferably about 1,500 to 5,000.

As another method for manufacturing a polarizer, first, a base film is prepared, a solution of a resin such as a polyvinyl alcohol-based resin is applied on the base film, and drying is performed to remove the solvent. Examples include a step of forming a resin layer. A primer layer can be formed in advance on the surface of the substrate film on which the resin layer is formed. A resin film such as PET can be used as the base film. Examples of the material for the primer layer include resins obtained by cross-linking hydrophilic resins used in polarizers.

Next, if necessary, the amount of solvent such as moisture in the resin layer is adjusted, then the base film and the resin layer are uniaxially stretched, and then the resin layer is dyed with a dichroic dye such as iodine to obtain two colors. The organic dye is adsorbed and oriented on the resin layer. Subsequently, if necessary, the resin layer on which the dichroic dye is adsorbed and oriented is treated with an aqueous boric acid solution, and a washing step is performed in which the aqueous boric acid solution is washed off. As a result, a resin layer in which the dichroic dye is adsorbed and oriented, that is, a polarizer film is produced. A known method can be adopted for each step.

The uniaxial stretching of the substrate film and the resin layer may be performed before dyeing, during dyeing, or during boric acid treatment after dyeing. Stretching may be performed. The base film and the resin layer may be uniaxially stretched in the MD direction (film transport direction). In this case, they may be uniaxially stretched between rolls with different peripheral speeds, or uniaxially stretched using hot rolls. You may Moreover, the base film and the resin layer may be uniaxially stretched in the TD direction (the direction perpendicular to the film transport direction), in which case a so-called tenter method can be used. The stretching of the substrate film and the resin layer may be dry stretching performed in the atmosphere, or wet stretching performed with the resin layer swollen with a solvent. In order to exhibit the performance of the polarizer, the draw ratio is 4 times or more, preferably 5 times or more, and particularly preferably 5.5 times or more. Although there is no particular upper limit for the draw ratio, it is preferably 8 times or less from the viewpoint of suppressing breakage and the like.

The polarizer produced by the above method can be obtained by laminating a protective layer to be described later and then peeling off the base film. According to this method, it is possible to further reduce the thickness of the polarizer.

As a method for producing a polarizer, which is a cured film obtained by aligning a dichroic dye in a polymerizable liquid crystal compound and polymerizing the polymerizable liquid crystal compound, a substrate film includes a polymerizable liquid crystal compound and a dichroic dye. A method of forming a polarizer by applying a polarizer-forming composition and polymerizing and curing a polymerizable liquid crystal compound while maintaining a liquid crystal state can be used. The polarizer thus obtained is in a state of being laminated on the substrate film, and the polarizer with the substrate film may be used as an optical film. Alternatively, after laminating a polarizer with a base film in which the base film can be peeled from the polarizer to the liquid crystal layer laminate 41 with a single-sided base layer via the second adhesive layer 32, or after laminating the peeling layer After lamination on the attached second adhesive layer 50, the base film may be peeled off and the polarizer may be used as an optical film.

As the dichroic dye, it is possible to use a dye having properties in which the absorbance in the long axis direction and the absorbance in the short axis direction of the molecule are different. For example, a dye having an absorption maximum wavelength (λmax) in the range of 300 to 700 nm. is preferred. Examples of such dichroic dyes include acridine dyes, oxazine dyes, cyanine dyes, naphthalene dyes, azo dyes, anthraquinone dyes, etc. Among them, azo dyes are preferred. Examples of azo dyes include monoazo dyes, bisazo dyes, trisazo dyes, tetrakisazo dyes, and stilbenazo dyes, with bisazo dyes and trisazo dyes being more preferred.

The polarizer-forming composition can contain a solvent, a polymerization initiator such as a photopolymerization initiator, a photosensitizer, a polymerization inhibitor, and the like. As the polymerizable liquid crystal compound, the dichroic dye, the solvent, the polymerization initiator, the photosensitizer, the polymerization inhibitor and the like contained in the polarizer-forming composition, known ones can be used. Those exemplified in JP-A-2017-102479 and JP-A-2017-83843 can be used. As the polymerizable liquid crystal compound, the same compounds as those exemplified as polymerizable liquid crystal compounds used to obtain the first liquid crystal layer and the second liquid crystal layer described later may be used. As for the method of forming a polarizer using the polarizer-forming composition, the methods exemplified in the above publications can be employed.

The thickness of the polarizer is preferably 2 μm or more, more preferably 3 μm or more. The thickness of the polarizer is 25 μm or less, preferably 15 μm or less, more preferably 13 μm or less, and further preferably 7 μm or less. In addition, the upper limit value and the lower limit value mentioned above can be combined arbitrarily. The thinner the thickness of the polarizer, the less rigid it becomes, and it is more susceptible to the shrinkage stress of the first liquid crystal layer and the second liquid crystal layer. Preferably, a first liquid crystal layer and a second liquid crystal layer having absolute values are used, and the first adhesive layer is an adhesive cured layer.

(Polarizer)
The polarizer can be made into a polarizing plate by laminating a protective layer on one side or both sides of the polarizer via a known pressure-sensitive adhesive layer or adhesive layer. This polarizing plate is a so-called linear polarizing plate. Protective layers that can be laminated on one or both sides of the polarizer include, for example, thermoplastic resins having excellent transparency, mechanical strength, thermal stability, moisture barrier properties, isotropy, stretchability, etc. A film is used. Specific examples of such thermoplastic resins include cellulose resins such as triacetyl cellulose; polyester resins such as polyethylene terephthalate and polyethylene naphthalate; polyethersulfone resins; polysulfone resins; polycarbonate resins; Resins; polyimide resins; polyolefin resins such as polyethylene, polypropylene, and ethylene/propylene copolymers; cyclic polyolefin resins having cyclo- and norbornene structures (also referred to as norbornene-based resins); (meth)acrylic resins; polyarylate resins; and polyvinyl alcohol resins, as well as mixtures thereof. When protective layers are laminated on both sides of the polarizer, the resin compositions of the two protective layers may be the same or different. In this specification, "(meth)acrylic" means either acrylic or methacrylic. "(Meth)" such as (meth)acrylate has the same meaning.

A film formed from a thermoplastic resin may be subjected to surface treatment (for example, corona treatment) in order to improve adhesion to a polarizer made of a PVA-based resin and a dichroic substance. A thin layer such as (also referred to as an undercoat layer) may be formed.

The protective layer preferably has a moisture permeability of 1 to 1500 g/m ² ·24 hr at a temperature of 40°C and a humidity of 90% RH. If the moisture permeability of the protective layer exceeds 1500 g/m ² ·24 hr, the polarizing plate may tend to curl over time in a high-temperature and high-humidity environment. The lower the moisture permeability of the protective layer, the easier it is to obtain the effect of suppressing the curling of the polarizing plate over time. The moisture permeability of the protective layer at a temperature of 40°C and a humidity of 90% RH is more preferably 1000 g/m ² ·24 hr or less, more preferably 100 g/m ² ·24 hr or less, and 10 g/m ² · Even more preferably, it is 24 hours or less. Moisture permeability can be measured according to JIS Z 0208:1976.

Furthermore, in the polarizing plate used as an optical film, it is preferable to increase the rigidity of the protective layer laminated on the polarizer in order to reduce the influence of the shrinkage stress of the first liquid crystal layer and the second liquid crystal layer. Here, the stiffness is defined as the product of the tensile elastic modulus of the film used for the protective layer at a temperature of 23° C. (hereinafter sometimes referred to as “23° C. elastic modulus”) and the film thickness. For example, a protective layer using a cellulose-based polymer represented by triacetyl cellulose preferably has a 23° C. elastic modulus in the range of 3000 to 5000 MPa, and a protective layer using an acrylic polymer represented by polymethyl methacrylate. preferably has a modulus of elasticity at 2000 to 4000 MPa at 23°C, and a protective layer using a cycloolefin-based polymer having a norbornene structure preferably has a modulus of elasticity at 2000 to 4000 MPa at 23°C. . For the outer protective layer, an acrylic polymer or a polyolefin polymer is preferably used from the viewpoint of moisture permeability and rigidity, and a cycloolefin polymer is particularly preferably used. The 23°C elastic modulus can be measured according to JIS K7113.

The protective layer may be, for example, a stretched thermoplastic resin, or may be a non-stretched one (hereinafter sometimes referred to as "unstretched resin"). The stretching treatment includes uniaxial stretching, biaxial stretching, and the like.

The stretching direction in the stretching process may be the length direction of the unstretched resin, the direction orthogonal to the length direction, or the direction oblique to the length direction. In the case of uniaxial stretching, the unstretched resin may be stretched in one of these directions. The biaxial stretching may be simultaneous biaxial stretching in which the film is simultaneously stretched in two of these directions, or sequential biaxial stretching in which the film is stretched in another direction after being stretched in a given direction.

The stretching process is performed, for example, by using two or more pairs of nip rolls whose peripheral speed is increased on the downstream side, to stretch in the length direction, or to grip both ends of the unstretched resin with a chuck and cross the length direction. This can be done by stretching in the direction of the film, or the like. At this time, it is possible to control the desired retardation value and wavelength dispersion by adjusting the thickness of the thermoplastic resin after stretching or adjusting the stretching ratio.

The stretched thermoplastic resin preferably satisfies the following formula.
(1) 80 nm≤Re(590)≤180 nm
(2) 0.5<Rth(590)/Re(590)≦0.8
(3) 0.85≦Re(450)/Re(550)<1.00
In the formula, Re (590), Re (450), and Re (550) represent in-plane retardation values at the measurement wavelengths of 590 nm, 450 nm, and 550 nm, respectively, and Rth (590) is the thickness direction retardation at the measurement wavelength of 590 nm. represents a value. These in-plane retardation value and thickness direction retardation value refer to values measured in an environment of a temperature of 23° C. and a relative humidity of 55%.

The in-plane retardation value Re and the thickness direction retardation value Rth are defined by nx as the refractive index in the in-plane slow axis direction and ny as the refractive index in the in-plane fast axis direction (direction perpendicular to the in-plane slow axis direction). , the refractive index in the thickness direction is nz, and the thickness of the stretched thermoplastic resin is d, the following formulas (S1) and (S2):
(S1) Re=(nx−ny)×d
(S2) Rth=[{(nx+ny)/2}-nz]×d
defined by

The outer protective layer described above is preferably a stretched thermoplastic resin that satisfies the above formulas (1) to (3). In addition, the outer protective layer described above is preferably attached to the polarizer so as to have a slow axis in a direction oblique to the absorption axis of the polarizer. It is preferable to laminate the outer protective layer and the polarizer together at 45±10° or 135±10° with respect to the absorption axis of the element. When the angle of the slow axis is within the above range, a difference occurs between the phase of light in the fast axis direction and the phase of light in the slow axis direction. , the light emitted through the optical laminate can be circularly polarized. Therefore, a display device in which the optical layered body of the present embodiment is applied to an optical display element can have excellent visibility even when a displayed image or the like is viewed through polarized sunglasses.

The thickness of the protective layer is preferably 3 μm or more, more preferably 5 μm or more. Moreover, the thickness of the protective layer is preferably 50 μm or less, more preferably 30 μm or less. In addition, the upper limit value and the lower limit value mentioned above can be combined arbitrarily. As the thickness of the polarizing plate becomes thinner, the rigidity becomes smaller, and the contraction stress of the first liquid crystal layer and the second liquid crystal layer becomes more susceptible. Preferably, a first liquid crystal layer and a second liquid crystal layer having absolute values are used, and the first adhesive layer is an adhesive cured layer.

The surface of the protective layer opposite to the polarizer may have a surface treatment layer, such as a hard coat layer, an antireflection layer, an antisticking layer, an antiglare layer, a diffusion layer, and the like. . The surface-treated layer may be another layer laminated on the protective layer, or may be formed by applying a surface treatment to the surface of the protective layer.

The hard coat layer is intended to prevent the surface of the polarizing plate from being scratched. For example, a cured film having excellent hardness and slip properties is added to the surface of the protective layer by UV curable resin such as acrylic or silicone. It can be formed by a method or the like. The purpose of the antireflection layer is to prevent reflection of external light on the surface of the polarizing plate, and this can be achieved by conventionally forming an antireflection film or the like. Also, the anti-sticking layer is intended to prevent adhesion with adjacent layers.

The anti-glare layer is intended to prevent external light from being reflected on the surface of the polarizing plate and hindering the visibility of light transmitted through the polarizing plate. The surface of the protective layer can be formed by imparting a fine uneven structure by a method such as a planarization method or a method of blending transparent fine particles. Examples of transparent fine particles used to impart a fine relief structure to the surface of the protective layer include silica, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, and antimony oxide having an average particle size of 0.5 to 50 μm. fine particles such as inorganic fine particles that can have conductivity, and organic fine particles such as crosslinked or uncrosslinked polymers. The content of the transparent fine particles is generally 2 to 50 parts by mass, preferably 5 to 25 parts by mass, with respect to 100 parts by mass of the resin forming the layer forming the fine uneven structure. The anti-glare layer may also serve as a diffusion layer (viewing angle enlarging function, etc.) for diffusing the light transmitted through the polarizing plate and enlarging the viewing angle.

When the surface treatment layer is a separate layer laminated on the protective layer of the polarizing plate, the thickness of the surface treatment layer is preferably 0.5 μm or more, more preferably 1 μm or more. Moreover, it is preferably 10 μm or less, more preferably 8 μm or less. If the thickness is less than 0.5 μm, it tends to be difficult to effectively prevent damage to the surface of the polarizing plate. On the other hand, if the thickness exceeds 10 μm, the reverse curling of the polarizing plate may become difficult to suppress due to, for example, increased curing shrinkage.

The optical layered body and the manufacturing method thereof according to the above embodiment are suitable when the thickness of the polarizing plate is 2 μm or more and 300 μm or less. The thickness of the polarizing plate may be 10 μm or more, 150 μm or less, 120 μm or less, or 80 μm or less.

(Polarizing plate with protective film)
A polarizing plate can be made into a polarizing plate with a protective film by laminating a protective film on one side thereof. The protection film includes a protection film resin film and a protection film pressure-sensitive adhesive layer laminated thereon. The thickness of the protective film can be, for example, 30-200 μm, preferably 40-150 μm, more preferably 50-120 μm.

Examples of the resin constituting the resin film for the protective film include polyolefin-based resins such as polyethylene-based resins and polypropylene-based resins; cyclic polyolefin-based resins; polyester-based resins such as polyethylene terephthalate and polyethylene naphthalate; polycarbonate-based resins; (Meth)acrylic resins and the like can be mentioned. Among these, polyester-based resins such as polyethylene terephthalate are preferable. The resin film for protective film may have a single-layer structure, or may have a multi-layer structure of two or more layers.

As the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer for the protective film, the same pressure-sensitive adhesive as that constituting the pressure-sensitive adhesive layer to be described later can be used. Moreover, a protection film can be obtained by forming an adhesive layer on the resin film surface for protection films by apply|coating and drying an adhesive composition. If necessary, the adhesive-coated surface of the resin film for the protective film may be subjected to surface treatment (for example, corona treatment) in order to improve adhesion, and a primer layer (also referred to as an undercoat layer) may be applied. A thin layer such as a layer may be formed. Moreover, you may have the peeling layer for covering and protecting the surface on the opposite side to the resin film side for protection films of the adhesive layer for protection films as needed. This peeling layer can be peeled off at an appropriate timing when it is attached to the polarizing plate.

In the process of producing a protective film-attached polarizing plate that bonds the protective film to the polarizing plate, a positive curl can be imparted in the length direction of the protective film-attached polarizing plate by imparting a tension difference or a peripheral speed difference. Therefore, when a polarizing plate with a protective film is used as the optical film in the optical layered body and the method for manufacturing the optical layered body of the above embodiments, positive curl is imparted to the polarizing plate with the protective film in the process of producing the polarizing plate with the protective film. Thereby, it can be expected that the reverse curling of the optical layered body can be more easily suppressed.

When the optical film 60 in the above embodiment is a polarizing plate with a protective film, the optical laminate and the method for producing the optical laminate in the above embodiment are suitable when the thickness of the polarizing plate with a protective film is 32 μm or more and 500 μm or less. The thickness of the polarizing plate with a protective film may be 40 μm or more, 350 μm or less, 200 μm or less, or 150 μm or less.

(Adhesive layer)
The adhesive layer refers to a layer composed of an adhesive. As used herein, the term "adhesive" refers to a so-called pressure-sensitive adhesive that exhibits adhesiveness when attached to an adherend such as an optical film or liquid crystal layer. . Moreover, the active energy ray-curable pressure-sensitive adhesive to be described later can be adjusted in degree of cross-linking and adhesive force by irradiating with an energy ray. As noted above, the second adhesive layer may be an adhesive layer.

As the adhesive, a conventionally known adhesive having excellent optical transparency can be used without particular limitation. For example, an adhesive having a base polymer such as acrylic, urethane, silicone, or polyvinyl ether is used. be able to. Active energy ray-curable adhesives, thermosetting adhesives, and the like may also be used. Among these, a pressure-sensitive adhesive using an acrylic resin as a base polymer, which is excellent in transparency, adhesive strength, removability (hereinafter also referred to as reworkability), weather resistance, heat resistance, etc., is suitable. The pressure-sensitive adhesive layer is preferably composed of a reaction product of a pressure-sensitive adhesive composition containing a (meth)acrylic resin (1), a cross-linking agent (2), and a silane compound (3), and other components (4). may contain

((Meth) acrylic resin (1))
The (meth)acrylic resin (1) contained in the pressure-sensitive adhesive composition is a structural unit derived from a (meth)acrylic acid alkyl ester represented by the following formula (I) (hereinafter also referred to as "structural unit (I)" ) as a main component (for example, containing 50% by mass or more of this) (hereinafter also referred to as “(meth)acrylic acid ester polymer”). As used herein, the term “originating” means that the chemical structure changes due to polymerization of a compound such as (meth)acrylic acid alkyl ester.

［式中、Ｒ^１０は、水素原子またはメチル基を表し、Ｒ^２０は、炭素数１～２０のアルキル基を表し、前記アルキル基は直鎖状、分岐状または環状のいずれの構造を有していてもよく、前記アルキル基の水素原子は、炭素数１～１０のアルコキシ基で置き換わっていてもよい。］

[In the formula, R ¹⁰ represents a hydrogen atom or a methyl group, R ²⁰ represents an alkyl group having 1 to 20 carbon atoms, and the alkyl group has a linear, branched or cyclic structure. or the hydrogen atom of the alkyl group may be replaced with an alkoxy group having 1 to 10 carbon atoms. ]

(Meth)acrylic acid esters represented by formula (I) include, for example, methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, i-propyl (meth)acrylate, n-butyl (meth)acrylate, i-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, i-hexyl (meth)acrylate, n-heptyl (meth)acrylate, n-octyl (meth)acrylate, i-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n- and i-nonyl (meth)acrylate, n-decyl (meth)acrylate, i-decyl (meth)acrylate, n-dodecyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, stearyl (meth)acrylate, t-butyl (meth)acrylate and the like. Specific examples of alkoxy group-containing alkyl acrylates include 2-methoxyethyl (meth)acrylate and ethoxymethyl (meth)acrylate. Among them, n-butyl (meth)acrylate or 2-ethylhexyl (meth)acrylate is preferred, and n-butyl (meth)acrylate is particularly preferred.

The (meth)acrylic acid ester polymer may contain structural units derived from monomers other than the structural unit (I). Structural units derived from other monomers may be one, or two or more. Other monomers that the (meth)acrylic acid ester polymer may contain include monomers having a polar functional group, monomers having an aromatic group, and acrylamide monomers.

Monomers having a polar functional group include (meth)acrylates having a polar functional group. Polar functional groups include hydroxy groups, carboxy groups, substituted amino groups, unsubstituted amino groups, and the like. Polar functional groups also include heterocyclic groups such as epoxy groups.

The content of structural units derived from a monomer having a polar functional group in the (meth)acrylic ester polymer is preferably 20 per 100 parts by mass of the total structural units of the (meth)acrylic ester polymer. 0.1 to 20 parts by mass, more preferably 0.1 to 10 parts by mass, and particularly preferably 0.5 to 10 parts by mass.

A monomer having an aromatic group has one (meth)acryloyl group and one or more aromatic rings (e.g., benzene ring, naphthalene ring, etc.) in the molecule, and includes a phenyl group, a phenoxyethyl group, or a (meth)acrylic acid ester having a benzyl group.

The content of the structural unit derived from the monomer having an aromatic group in the (meth)acrylic ester polymer is preferably 50 per 100 parts by mass of the total structural units of the (meth)acrylic ester polymer. It is not more than 4 parts by mass and not more than 50 parts by mass, more preferably not less than 4 parts by mass and not more than 25 parts by mass.

Examples of acrylamide-based monomers include N-(methoxymethyl)acrylamide, N-(ethoxymethyl)acrylamide, N-(propoxymethyl)acrylamide, N-(butoxymethyl)acrylamide, and N-(2-methylpropoxymethyl)acrylamide. etc. By including these structural units, it is possible to suppress the bleeding out of additives such as antistatic agents, which will be described later.

Furthermore, structural units derived from monomers other than the structural unit (I) include structural units derived from styrene-based monomers, structural units derived from vinyl-based monomers, and multiple (meta ) Structural units and the like derived from a monomer having an acryloyl group may be included.

The (meth)acrylic resin (1) preferably has a weight average molecular weight (hereinafter also simply referred to as “Mw”) of 500,000 to 2,500,000. When the weight-average molecular weight is 500,000 or more, the durability of the pressure-sensitive adhesive layer under high-temperature and high-humidity environments can be improved. When the weight-average molecular weight is 2,500,000 or less, the operability at the time of coating the coating liquid containing the pressure-sensitive adhesive composition is improved. The molecular weight distribution (Mw/Mn) represented by the ratio of the weight average molecular weight (Mw) to the number average molecular weight (hereinafter also simply referred to as “Mn”) is usually 2-10. As used herein, "weight average molecular weight" and "number average molecular weight" are polystyrene-equivalent values measured by a gel permeation chromatography (GPC) method.

When the (meth)acrylic resin (1) is dissolved in ethyl acetate to form a solution having a concentration of 20% by mass, the viscosity at 25° C. is preferably 20 Pa s or less, preferably 0.1 to 15 Pa s. is more preferable. When the viscosity at 25° C. of the (meth)acrylic resin (1) is within the above range, it contributes to reworkability and the like. The viscosity can be measured with a Brookfield viscometer.

The glass transition temperature of the (meth)acrylic resin (1) is preferably -10°C to -60°C from the viewpoint of achieving both adhesiveness and durability. The glass transition temperature can be measured with a differential scanning calorimeter (DSC).

The (meth)acrylic resin (1) may contain two or more (meth)acrylic acid ester polymers. Examples of such a (meth)acrylic acid ester polymer include, for example, those having the structural unit (I) derived from the (meth)acrylic acid ester as a main component and having a weight average molecular weight of 50,000 to 300,000. and relatively low molecular weight (meth)acrylic acid ester polymers such as those in the range of

(Crosslinking agent (2))
The adhesive composition forming the adhesive layer preferably contains a cross-linking agent (2). Examples of the cross-linking agent (2) include conventional cross-linking agents (e.g., isocyanate compounds, epoxy compounds, aziridine compounds, metal chelate compounds, peroxides, etc.). From the point of view, it is preferably an isocyanate compound.

The isocyanate compound is preferably a compound having at least two isocyanato groups (--NCO) in the molecule, such as aliphatic isocyanate compounds (eg hexamethylene diisocyanate), alicyclic isocyanate compounds (eg isophorone diisocyanate ), hydrogenated xylylene diisocyanate, hydrogenated diphenylmethane diisocyanate, aromatic isocyanate compounds (eg, tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, triphenylmethane triisocyanate, etc.). Further, the cross-linking agent (2) is an adduct (adduct) of the above isocyanate compound with a polyhydric alcohol compound [e.g., an adduct with glycerol, trimethylolpropane, etc.], an isocyanurate compound, a buret type compound, a polyether polyol, Derivatives such as urethane prepolymer-type isocyanate compounds obtained by addition reaction with polyester polyols, acrylic polyols, polybutadiene polyols, polyisoprene polyols and the like may also be used. The cross-linking agent (2) can be used alone or in combination of two or more. Among these, tolylene diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, polyhydric alcohol compounds thereof, or isocyanurate compounds thereof are preferred from the viewpoint of durability.

The ratio of the cross-linking agent (2) is, for example, 0.01 to 10 parts by mass, preferably 0.1 to 3 parts by mass, more preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the (meth)acrylic resin (1). It may be 1 to 1 part by mass. When it is equal to or less than the above upper limit, it is advantageous for improving durability, and when it is equal to or more than the above lower limit, it is advantageous for suppressing gas generation and improving reworkability.

(Silane compound (3))
The adhesive composition contains a silane compound (3). By containing the silane compound (3), the adhesion between the pressure-sensitive adhesive layer and the layer to be laminated can be enhanced. Two or more silane compounds (3) may be used.

Examples of the silane compound (3) include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(2-methoxyethoxy)silane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3 - glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylethoxydimethylsilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane and the like.

Moreover, the silane compound (3) can contain an oligomer derived from the silane compound (3).

The content of the silane compound (3) in the adhesive composition is usually 0.01 to 10 parts by mass, preferably 0.03 to 5 parts by mass, relative to 100 parts by mass of the (meth)acrylic resin (1). parts, more preferably 0.05 to 2 parts by mass, and still more preferably 0.1 to 1 part by mass. When the content of the silane compound (3) is 0.01 parts by mass or more, the adhesion between the pressure-sensitive adhesive layer and an adherend such as an optical film or a liquid crystal layer is likely to be improved. When the content is 10 parts by mass or less, bleeding out of the silane compound (3) from the pressure-sensitive adhesive layer can be suppressed.

(Other components (4))
The pressure-sensitive adhesive composition forming the pressure-sensitive adhesive layer contains, as other components (4), an antistatic agent using an ionic compound or the like, a solvent, a crosslinking catalyst, a tackifying resin (tackifier), a plasticizer, and a weather stabilizer. , softeners, dyes, pigments, inorganic fillers, and resins other than acrylic resins.

(Active energy ray-curable adhesive)
It is also useful to add an ultraviolet curable compound such as a polyfunctional acrylate to the adhesive composition, form an adhesive layer, and then irradiate and cure the adhesive layer to form a harder adhesive layer. A linear curing adhesive can be used. The "active energy ray-curable pressure-sensitive adhesive" has the property of being cured by being irradiated with energy rays such as ultraviolet rays and electron beams. Activated energy ray-curable adhesives are sticky even before energy ray irradiation, so they adhere to adherends such as optical films and liquid crystal layers, and are cured by energy ray irradiation to increase adhesion. It is an adhesive with properties that can be adjusted.

An active energy ray-curable pressure-sensitive adhesive generally contains an acrylic pressure-sensitive adhesive and an energy ray-polymerizable compound as main components. Usually, a cross-linking agent is further blended, and if necessary, a photopolymerization initiator, a photosensitizer, etc. can also be blended.

The adhesive layer preferably has a storage modulus of 0.10 to 10.0 MPa at 23° C., more preferably 0.15 to 5.0 MPa. When the storage elastic modulus at 23° C. is 0.10 MPa or more, problems such as peeling can be suppressed when the temperature changes, which is preferable. Further, when the pressure is 10.0 MPa or less, deterioration in durability due to reduction in adhesive strength is less likely to occur, which is preferable. The storage elastic modulus of the pressure-sensitive adhesive layer can be measured by the method described in Examples.

The thickness of the adhesive layer is preferably 3 μm or more, more preferably 5 μm or more. Moreover, the thickness of the pressure-sensitive adhesive layer is preferably 40 μm or less, more preferably 30 μm or less. In addition, the upper limit value and the lower limit value mentioned above can be combined arbitrarily.

(Adhesive cured layer)
The adhesive cured layer refers to a layer formed by curing the curable component in the adhesive composition. The adhesive composition for forming the adhesive-cured layer includes adhesives other than pressure-sensitive adhesives (adhesives), such as water-based adhesives and active energy ray-curable adhesives. Examples of water-based adhesives include adhesives obtained by dissolving or dispersing a polyvinyl alcohol-based resin in water. Examples of active energy ray-curable adhesives include 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. mentioned. Adhesion between layers can be improved by using a non-solvent type active energy ray-curable adhesive. On the other hand, if the active energy ray-curable adhesive contains a solvent (particularly an organic solvent), sufficient adhesion can be obtained even if the curable components contained in the adhesive are the same. Therefore, when the optical layered body is cut into a predetermined size, problems such as peeling at the ends thereof are likely to occur. In addition, since a step of drying the solvent is added, an additional shrinkage stress due to heat is applied, and there is a possibility that reverse curling may easily occur in the optical layered body.

When a solvent-free active energy ray-curable adhesive containing a curable compound that is cured by irradiation with an active energy ray is used, storage elasticity is an index that indicates the hardness of the activated energy ray-curable adhesive after curing. The stiffness multiplied by the thickness is often higher than the stiffness of the water-based adhesive after curing. In order to increase the rigidity of the adhesive-cured layer provided between the first liquid crystal layer and the second liquid crystal layer, it is preferable to use a non-solvent type activation energy ray-curable adhesive.

The active energy ray-curable adhesive preferably contains either one or both of a cationically 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 or a radical polymerization initiator for initiating the curing reaction of the curable compound.

Examples of cationic polymerizable curable compounds include epoxy compounds (compounds having one or more epoxy groups in the molecule) and oxetane compounds (one or two or more oxetane rings in the molecule). compound), or a combination 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. or a combination thereof.

The active energy ray-curable adhesive can contain a sensitizer 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 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.

The adhesive composition layer may be formed by applying the adhesive composition to the joint surfaces of the first liquid crystal layer with the base layer and the second liquid crystal layer with the base layer. Usual coating techniques using a die coater, a comma coater, a reverse roll coater, a gravure coater, a rod coater, a wire bar coater, a doctor blade coater, an air doctor coater, etc. may be employed as the coating method.

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.

When an active energy ray-curable adhesive is used, the adhesive composition layer is cured by irradiating with an active energy ray such as ultraviolet rays, visible light, electron beams, and X-rays to form an adhesive cured layer. can be done. 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.

When the adhesive composition layer is cured by ultraviolet irradiation, the intensity of ultraviolet light irradiation is determined for each composition of the adhesive composition and is not particularly limited, but is 10 to 1,000 mW/cm ² . preferably 100 to 600 mW/cm ² . If the light irradiation intensity to the resin composition is less than 10 mW/cm ² , the reaction time will be too long, and if it exceeds 1,000 mW/cm ² , heat radiated from the light source and polymerization of the adhesive composition will be delayed. Heat generation may cause yellowing of the resulting cured adhesive layer. Also, the heat radiated from the light source can cause additional shrinkage stress. The irradiation intensity is an intensity in a wavelength region effective for activating a polymerization initiator, preferably a photocationic polymerization initiator, more preferably an intensity in a wavelength region of 400 nm or less, still more preferably 280 to 320 nm. is the intensity in the wavelength domain. Irradiate once or multiple times with such a light irradiation intensity so that the integrated light amount is 10 mJ/cm ² or more, preferably 100 to 1,000 mJ/cm ² , more preferably 200 to 600 mJ/cm ² . It is preferable to set If the integrated amount of light to the adhesive composition layer is less than 10 mJ/cm ² , generation of active species derived from the polymerization initiator is insufficient, resulting in insufficient curing of the adhesive composition layer. If the integrated amount of light exceeds 1,000 mJ/cm ² , the irradiation time becomes very long, which is disadvantageous for improving productivity. Also, the heat radiated from the light source can cause additional shrinkage stress. Depending on the type of the first substrate layer, second substrate layer, first liquid crystal layer, second liquid crystal layer, etc., and the combination of components in the adhesive composition, the wavelength at the time of light irradiation (UVA (320 to 390 nm) , UVB (280 to 320 nm), etc.), and the required integrated amount of light changes according to the wavelength at the time of light irradiation.

The viscosity of the active energy ray-curable adhesive may be selected so that it can be applied by any application method. More preferably, it is in the range of 20 to 500 mPa·sec. If the viscosity is too low, it tends to be difficult to form a cured adhesive layer with a desired thickness. On the other hand, if the viscosity is too high, the active energy ray-curable adhesive becomes difficult to flow during coating, which tends to make it difficult to obtain a uniform and uniform coating film. The viscosity here is a value measured at 10 rps after adjusting the temperature of the adhesive to 25° C. using an E-type viscometer.

(Adhesive layer with release layer)
The pressure-sensitive adhesive layer with a release layer (including the second adhesive layer with a release layer when the pressure-sensitive adhesive layer is used as the second adhesive layer) is formed, for example, by applying a pressure-sensitive adhesive composition on the release-treated surface of the release layer. It can be obtained by forming a pressure-sensitive adhesive layer by applying, drying, or the like. The pressure-sensitive adhesive layer with a release layer may optionally have another release layer for covering and protecting the surface of the pressure-sensitive adhesive layer opposite to the release layer side. The release layer and other release layers can be peeled off at an appropriate timing.

(Release layer)
The first release layer and the second release layer (hereinafter collectively referred to as "release layer") are releasable from the adhesive layer, and the adhesive layer formed on the release layer and protect the pressure-sensitive adhesive layer. A known release film or release paper can be used as the release layer. For example, a release treatment such as silicone coating is applied to a film formed of a resin material exemplified as the base layer to be described later. may Materials similar to those of the peeling layer can be used for other peeling layers as well.

The release layer can be separated from the adhesive layer, and the magnitude of the release force between the release layer and the adhesive layer must be determined in consideration of the order in which the release layers are separated. The peel force was measured by preparing a test piece for measurement (length 200 mm, width 25 mm) having a pressure-sensitive adhesive layer on the peel layer, bonding it to a glass of an appropriate size, and autograph manufactured by Shimadzu Corporation ( AGS-50NX) was used to chuck the partially peeled peeling layer and the glass so as to form a peeling starting point, and the peeling layer was peeled off in the direction of 180° at a speed of 300 mm / min. The measured peel strength can be taken as the peel force. The peel force between the release layer and the adhesive layer is preferably 0.01 to 0.20 N/25 mm, more preferably 0.02 to 0.10 N/25 mm, and 0.02 to 0 More preferably 0.06 N/25 mm. If it is less than 0.01 N/25 mm, the release layer and the pressure-sensitive adhesive layer may lift during transportation. On the other hand, if it exceeds 0.20 N/25 mm, the adhesion between the release layer and the adhesive layer is high and the release layer is difficult to separate from the adhesive layer. , part of the adhesive layer is attached to the peeled release layer, or peeling between unintended layers (for example, the layer bonded on the opposite side of the adhesive layer separation from the agent layer) may occur.

(liquid crystal layer)
The first liquid crystal layer and the second liquid crystal layer (hereinafter collectively referred to as "liquid crystal layer") are cured layers formed by polymerizing a polymerizable liquid crystal compound, and are retardation layers. There may be. The optical properties of the liquid crystal layer can be adjusted by the alignment state of the polymerizable liquid crystal compound.

In this specification, the optic axis of the polymerizable liquid crystal compound is aligned horizontally with respect to the substrate layer plane, and the optic axis of the polymerizable liquid crystal compound is aligned vertically with respect to the substrate layer plane. Define vertical orientation. The optic axis means the direction in which the cross section cut out in the direction orthogonal to the optical axis becomes a circle in the refractive index ellipsoid formed by the orientation of the polymerizable liquid crystal compound, that is, the direction in which the refractive indices in the two directions are equal. .

Examples of the polymerizable liquid crystal compound include a rod-like polymerizable liquid crystal compound and a disk-like polymerizable liquid crystal compound. When the rod-shaped polymerizable liquid crystal compound is aligned horizontally or vertically with respect to the substrate layer, 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.

In order for a liquid crystal layer formed by polymerizing a polymerizable liquid crystal compound to exhibit an in-plane retardation, the polymerizable liquid crystal compound may be oriented in a suitable direction. When the polymerizable liquid crystal compound is rod-shaped, an in-plane retardation is expressed by aligning the optical axis of the polymerizable liquid crystal compound horizontally with respect to the plane of the substrate layer. match the direction. When the polymerizable liquid crystal compound has a discotic shape, an in-plane retardation is expressed by aligning the optical axis of the polymerizable liquid crystal compound horizontally with respect to the plane of the substrate layer, and in this case, the optical axis and the slow axis are orthogonal to The alignment state of the polymerizable liquid crystal compound can be adjusted by a combination of the alignment film and the polymerizable liquid crystal compound.

A polymerizable liquid crystal compound is a compound having a polymerizable group and liquid crystallinity. A polymerizable group means a group that participates in a polymerization reaction, and is preferably a photopolymerizable group. Here, the photopolymerizable group means a group that can participate in a polymerization reaction by an active radical generated from a photopolymerization initiator described below, an acid, or the like. Examples of the polymerizable group include vinyl group, vinyloxy group, 1-chlorovinyl group, isopropenyl group, 4-vinylphenyl group, acryloyloxy group, methacryloyloxy group, oxiranyl group and oxetanyl group. Among them, an acryloyloxy group, a methacryloyloxy 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.

As the rod-shaped polymerizable liquid crystal compound and the disk-shaped polymerizable liquid crystal compound, known ones can be used. Those exemplified in JP-A-158940 and JP-A-2016-224128 can be used.

The liquid crystal layer may have a one-layer structure or a multi-layer structure of two or more layers. In the case of having a multi-layered structure of two or more layers, a liquid crystal layer having a multi-layered structure of two or more layers may be formed on the base layer when preparing a liquid crystal layer with a base layer to be described later. When the liquid crystal layer has a single-layer structure, the thickness of the liquid crystal layer is preferably 0.3 μm or more, may be 1 μm or more, and is usually 10 μm or less, may be 5 μm or less, or may be 3 μm or less. Preferably. When the liquid crystal layer has a multilayer structure of two or more layers, the thickness of the liquid crystal layer is preferably 0.5 μm or more, may be 1 μm or more, is usually 10 μm or less, and may be 5 μm or less. It is preferably 3 μm or less. The thickness of the liquid crystal layer is preferably 5 μm or less, more preferably 3 μm or less, from the viewpoint of contributing to thinning of the polarizing plate as a whole and effectively suppressing possible reverse curling.

(Liquid crystal layer with substrate layer)
The first liquid crystal layer with a substrate layer and the second liquid crystal layer with a substrate layer (hereinafter, both of them may be collectively referred to as "liquid crystal layer with a substrate layer") are formed by coating a polymerizable liquid crystal compound on the substrate layer. It can be obtained by forming a liquid crystal layer which is a cured layer formed by applying and drying a liquid crystal layer forming composition containing and polymerizing a polymerizable liquid crystal compound. The composition for forming a liquid crystal layer may be applied onto the alignment layer when the alignment layer described later is formed on the substrate layer, and when the liquid crystal layer has a multilayer structure of two or more layers, A multilayer structure may be formed by, for example, sequentially applying the layer-forming composition.

The liquid crystal layer-forming composition usually contains a solvent in addition to the polymerizable liquid crystal compound. The liquid crystal layer-forming composition may further contain a polymerization initiator, a reactive additive, a polymerization inhibitor, and the like. For solvents, polymerization initiators, reactive additives, polymerization inhibitors, etc., see JP 2015-163937, JP 2016-42185, WO 2016/158940, JP 2016-224128. Any of the exemplified ones can be used.

The liquid crystal layer-forming composition can be applied by, for example, a spin coating method, an extrusion method, a gravure coating method, a die coating method, a slit coating method, a bar coating method, an applicator method, or a flexographic method. It can be carried out by a known method such as a printing method. After coating the composition for forming a liquid crystal layer, it is preferable to remove the solvent under conditions that do not polymerize the polymerizable liquid crystal compound contained in the coating layer. Examples of the drying method include natural drying, ventilation drying, heat drying, and reduced pressure drying.

Polymerization of the polymerizable liquid crystal compound after drying the coating layer can be carried out by a known method for polymerizing a compound having a polymerizable functional group. Examples of the polymerization method include thermal polymerization and photopolymerization, and photopolymerization is preferred from the viewpoint of ease of polymerization. When the polymerizable liquid crystal compound is polymerized by photopolymerization, a composition containing a photopolymerization initiator is used as the composition for forming the liquid crystal layer, the composition for forming the liquid crystal layer is applied, dried, and in the dried film after drying. It is preferable to align the polymerizable liquid crystal compound contained and perform photopolymerization while maintaining this liquid crystal alignment state.

The photopolymerization can be carried out by irradiating the polymerizable liquid crystal compound in the dry film with the liquid crystal alignment with an active energy ray. The active energy ray to be irradiated can be appropriately selected according to the type and amount of the polymerizable group possessed by the polymerizable liquid crystal compound, the type of the photopolymerization initiator, etc. Examples include visible light, ultraviolet light, and laser light. , X-rays, α-rays, β-rays and γ-rays. Among these, ultraviolet rays are preferable because the progress of the polymerization reaction can be easily controlled and a photopolymerization device widely used in the art can be used. and the type of photopolymerization initiator is preferably selected. In the photopolymerization, the polymerization temperature can be controlled by irradiating the active energy ray while cooling the dry film with an appropriate cooling means.

(Base material layer)
The first base layer and the second base layer (hereinafter both may be collectively referred to as "base layers") are the first orientation layer and the second orientation layer formed on these base layers, which will be described later. It functions as an alignment layer and a support layer that supports the first liquid crystal layer and the second liquid crystal layer. The base layer is preferably a film made of a resin material.

As the resin material, for example, a resin material having excellent transparency, mechanical strength, thermal stability, stretchability and the like is used. Specifically, polyolefin-based resins such as polyethylene and polypropylene; cyclic polyolefin-based resins such as norbornene-based polymers; polyester-based resins such as polyethylene terephthalate and polyethylene naphthalate; (Meth) acrylic acid-based resins; cellulose ester-based resins such as triacetyl cellulose, diacetyl cellulose, and cellulose acetate propionate; vinyl alcohol-based resins such as polyvinyl alcohol and polyvinyl acetate; polycarbonate-based resins; Arylate-based resins; polysulfone-based resins; polyethersulfone-based resins; polyamide-based resins; polyimide-based resins; polyetherketone-based resins; can be done. Among these resins, it is preferable to use any one of cyclic polyolefin-based resin, polyester-based resin, cellulose ester-based resin and (meth)acrylic acid-based resin, or a mixture thereof.

The substrate layer may be a single layer obtained by mixing one or more resins, or may have a multilayer structure of two or more layers. When it has a multi-layer structure, the resin forming each layer may be the same or different, and may be a coated/cured layer such as a hard coat layer.

Arbitrary additives may be added to the resin material forming the film formed of the resin material. Examples of additives include ultraviolet absorbers, antioxidants, lubricants, plasticizers, release agents, anti-coloring agents, flame retardants, nucleating agents, antistatic agents, pigments, and colorants.

The thickness of the first base layer and the second base layer is not particularly limited, but in general, it is preferably 1 to 300 μm, more preferably 10 to 200 μm, from the viewpoint of workability such as strength and handleability. More preferably, it is still more preferably 30 to 120 μm.

When the first liquid crystal layer with a substrate layer has a first alignment layer described later, or when the second liquid crystal layer with a substrate layer has a second alignment layer described later, the first substrate layer and the first alignment layer and the adhesion between the second substrate layer and the second alignment layer, at least the surface of the first substrate layer on which the first alignment layer is formed, and at least the second The surface of the substrate layer on which the second alignment layer is to be formed may be subjected to corona treatment, plasma treatment, flame treatment, or the like, and a primer layer or the like may be formed thereon.

The substrate layer can be peeled off from the liquid crystal layer or an alignment layer (first alignment layer or second alignment layer) described later, and the magnitude of the peeling force between the substrate layer and the liquid crystal layer or the alignment layer is must be determined in consideration of the order in which the substrate layers are peeled off. The peel force is measured using a test piece for measurement having a liquid crystal layer on a substrate layer, or a test piece for measurement having an alignment layer and a liquid crystal layer on a substrate layer, except for using a test piece for measurement having an alignment layer and a liquid crystal layer on a substrate layer. It can be measured in the same manner as the method of measuring the peel force between. The peel force between the substrate layer and the liquid crystal layer or alignment layer is preferably 0.01 to 0.50 N/25 mm, more preferably 0.03 to 0.20 N/25 mm, and 0.03 to 0.20 N/25 mm. More preferably, it is 05 to 0.18 N/25 mm. If the peel strength is less than the above lower limit, there is a risk that the substrate layer and the liquid crystal layer or the alignment layer may be lifted during transportation. In addition, if the peel force exceeds the above upper limit, the adhesiveness is too high, so that the optical laminate cannot be transferred to the other liquid crystal layer or the optical film, or the liquid crystal layer or the liquid crystal layer and the alignment layer. In the manufacturing process, there is a possibility that the separation interface may change while each member is conveyed.

The peeling force between the first substrate layer and the first liquid crystal layer or the first alignment layer described later (hereinafter sometimes referred to as "first peeling force"), the second substrate layer and the second liquid crystal layer Alternatively, the difference from the peel strength (hereinafter sometimes referred to as "second peel strength") to the second alignment layer described later is preferably 0.01 N/25 mm or more, and 0.03 N/25 mm It is more preferable to be above. When the first substrate layer is first peeled from the liquid crystal layer laminate with the substrate layer, the second peel force is preferably larger than the first peel force.

(Orientation layer)
The first liquid crystal layer with substrate layer may include a first alignment layer between the first substrate layer and the first liquid crystal layer. The second liquid crystal layer with base layer may also include a second alignment layer between the second base layer and the second liquid crystal layer.

The first alignment layer and the second alignment layer have an alignment control force that aligns the liquid crystal compound contained in the first liquid crystal layer and the second liquid crystal layer formed on these alignment layers in a desired direction. As the first alignment layer and the second alignment layer, an alignment polymer layer formed of an alignment polymer, a photo-alignment polymer layer formed of a photo-alignment polymer, and a layer surface having an uneven pattern or a plurality of grooves (grooves). The first and second alignment layers may be layers of the same type or layers of different types. The thickness of the first alignment layer and the second alignment layer is usually 10-4000 nm, preferably 50-3000 nm.

The oriented polymer layer is formed by applying a composition in which an oriented polymer is dissolved in a solvent to the substrate layer (first substrate layer or second substrate layer), removing the solvent, and rubbing if necessary. can be formed by In this case, the alignment regulating force can be arbitrarily adjusted by the surface state of the oriented polymer and the rubbing conditions in the oriented polymer layer formed of the oriented polymer.

The photo-alignable polymer layer is formed by applying a composition containing a polymer having a photoreactive group or a monomer and a solvent to the substrate layer (first substrate layer or second substrate layer) and irradiating light such as ultraviolet rays. can be formed by In particular, when the alignment control force is exhibited in the horizontal direction, it can be formed by irradiating polarized light. In this case, the orientation regulating force in the photo-alignable polymer layer can be arbitrarily adjusted by the polarized light irradiation conditions for the photo-alignable polymer.

The groove alignment layer can be formed, for example, by exposing the surface of the photosensitive polyimide film through an exposure mask having pattern-shaped slits and developing to form an uneven pattern. A method of forming an uncured layer of an energy ray-curable resin, transferring this layer to a substrate layer (first substrate layer or second substrate layer) and curing the substrate layer (first substrate layer Alternatively, an uncured layer of an active energy ray-curable resin is formed on the second base material layer), and a roll-shaped master plate having unevenness is pressed against this layer to form unevenness, and then cured. can do.

When the first liquid crystal layer with a substrate layer includes a first alignment layer, the first alignment layer may be peeled off together with the first substrate layer when the first substrate layer is peeled off. , the first alignment layer may remain. When the second liquid crystal layer with a substrate layer includes a second alignment layer, the second alignment layer may be peeled off together with the second substrate layer when the second substrate layer is peeled off. A second alignment layer may remain on the substrate. Whether the first alignment layer is peeled off together with the first substrate layer or remains on the first liquid crystal layer can be set by adjusting the relationship of adhesion between the layers. The surface treatment such as corona treatment, plasma treatment, flame treatment, primer layer, etc., which is performed on the substrate layer, and the components of the composition for forming the liquid crystal layer used to form the first liquid crystal layer are adjusted. can be done. Similarly, the surface treatment performed on the second substrate layer may cause the second alignment layer to be peeled off together with the second substrate layer, or may remain on the second liquid crystal layer.

If the first alignment layer remains on the first liquid crystal layer, the first adhesive layer can be provided on the first alignment layer. Also, when the second alignment layer remains on the second liquid crystal layer, the second adhesive layer can be provided on the second alignment layer.

(Circularly polarizing plate)
The optical laminate of this embodiment can be used as a circularly polarizing plate. 6B is used as a circularly polarizing plate, the optical film 60 is a polarizer, a polarizing plate, or a polarizing plate with a protective film, and the first liquid crystal layer 12 is 1/ A two-wave retardation layer may be used, and the second liquid crystal layer 22 may be a quarter-wave retardation layer. Alternatively, in the same manner as described above, the optical film 60 is a polarizer, a polarizing plate, or a polarizing plate with a protective film, and the first liquid crystal layer 12 is a quarter-wave retardation layer with reverse wavelength dispersion, A circularly polarizing plate can also be obtained by using a positive C plate as the second liquid crystal layer 22 .

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

[Preparation of adhesive layer with double-sided separator]
An adhesive was produced by the following method. 97.0 parts of n-butyl acrylate, 1.0 part of acrylic acid, and 0.5 part of 2-hydroxyethyl acrylate are placed in a reaction vessel equipped with a stirrer, thermometer, reflux condenser, dropping device and nitrogen inlet tube. , 200 parts of ethyl acetate, and 0.08 part of 2,2'-azobisisobutyronitrile were charged, and the air in the reaction vessel was replaced with nitrogen gas. The temperature of the reaction solution was raised to 60° C. while stirring under a nitrogen atmosphere, and the reaction solution was allowed to react for 6 hours, after which it was cooled to room temperature. When the weight average molecular weight of part of the obtained solution was measured, it was confirmed that a (meth)acrylic acid ester polymer of 1.8 million was obtained.

100 parts of the (meth)acrylic acid ester polymer obtained above (solid content conversion value; the same applies hereinafter), and trimethylolpropane-modified tolylene diisocyanate (manufactured by Tosoh Corporation, trade name "Coronate L") as an isocyanate-based cross-linking agent ) and 0.30 parts of 3-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name “KBM403”) as a silane coupling agent are mixed and sufficiently stirred to obtain By diluting with ethyl acetate, a coating solution of the adhesive composition was obtained.

After applying the coating solution of the pressure-sensitive adhesive composition with an applicator to the release-treated surface (release surface) of the first separator (manufactured by Lintec Corporation: SP-PLR382190) that forms the release layer, it is applied at 100 ° C. for 1 Dry for a minute to form an adhesive layer, and attach another second separator (manufactured by Lintec: SP-PLR381031) to the opposite side of the adhesive layer to which the separator is attached, with a double-sided separator. An adhesive layer was obtained.

[Preparation of Adhesive Composition]
After mixing the cationic curable components a1 to a3 and the cationic polymerization initiator shown below, the cationic polymerization initiator and the sensitizer shown below are further mixed, and then defoamed to obtain a photocurable adhesive composition. was prepared. In addition, the following compounding quantity is based on solid content.
- Cationic curable component a1 (70 parts):
3′,4′-epoxycyclohexylmethyl 3′,4′-epoxycyclohexane carboxylate (trade name: CEL2021P, manufactured by Daicel Corporation)
- Cationic curable component a2 (20 parts):
Neopentyl glycol diglycidyl ether (trade name: EX-211, manufactured by Nagase ChemteX Corporation)
- Cationic curable component a3 (10 parts):
2-ethylhexyl glycidyl ether (trade name: EX-121, manufactured by Nagase ChemteX Corporation)
- Cationic polymerization initiator (2.25 parts (solid content)):
Product name: 50% propylene carbonate solution of CPI-100 (manufactured by San-Apro Co., Ltd.) Sensitizer (2 parts):
1,4-diethoxynaphthalene

・溶剤（９５部）：シクロペンタノン [Preparation of First Liquid Crystal Layer with Base Layer and Second Liquid Crystal Layer with Base Layer]
(Preparation of composition (1) for forming photo-alignment layer)
The composition (1) 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-orientable material (5 parts):

- Solvent (95 parts): cyclopentanone

(Preparation of alignment layer-forming composition (2))
2-Butoxyethanol was added to Sanever SE-610 (manufactured by Nissan Chemical Industries, Ltd.), which is a commercially available oriented polymer, to obtain an orientation layer forming composition (2). The resulting alignment layer-forming composition (2) had a solid content of 1% relative to the total amount of the composition, and a solvent content of 99% relative to the total amount of the composition. The solid content of Sunever SE-610 was converted from the concentration described in the delivery specifications.

・重合性液晶化合物Ａ２（２０部）：

・重合開始剤（６部）：
２－ジメチルアミノ－２－ベンジル－１－（４－モルホリノフェニル）ブタン－１－オン（イルガキュア３６９；チバスペシャルティケミカルズ社製）
・溶剤（４００部）：シクロペンタノン (Preparation of liquid crystal layer forming composition (A-1))
The following components were mixed and the resulting mixture was stirred at 80° C. for 1 hour to obtain a liquid crystal layer-forming composition (A-1). Polymerizable liquid crystal compound A1 and polymerizable liquid crystal compound A2 were synthesized by the method described in JP-A-2010-31223.
- Polymerizable liquid crystal compound A1 (80 parts):

- Polymerizable liquid crystal compound A2 (20 parts):

- Polymerization initiator (6 parts):
2-dimethylamino-2-benzyl-1-(4-morpholinophenyl)butan-1-one (Irgacure 369; manufactured by Ciba Specialty Chemicals)
- Solvent (400 parts): cyclopentanone

・重合開始剤（０．５％）：
イルガキュア（登録商標）９０７（ＢＡＳＦジャパン社製）
・反応添加剤（１．１％）：
Ｌａｒｏｍｅｒ（登録商標）ＬＲ－９０００（ＢＡＳＦジャパン社製）
・溶剤（７９．１％）：プロピレングリコール１－モノメチルエーテル２－アセタート (Preparation of liquid crystal layer forming composition (B-1))
After the following components were mixed and the resulting mixture was stirred at 80° C. for 1 hour, the mixture was cooled to room temperature to obtain a liquid crystal layer forming composition (B-1).
· Polymerizable liquid crystal compound LC242 (manufactured by BASF) (19.2%):

- Polymerization initiator (0.5%):
Irgacure (registered trademark) 907 (manufactured by BASF Japan)
- Reactive additive (1.1%):
Laromer (registered trademark) LR-9000 (manufactured by BASF Japan)
・Solvent (79.1%): propylene glycol 1-monomethyl ether 2-acetate

(Production of first liquid crystal layer (i) with substrate layer)
A polyethylene terephthalate (PET) film (first base layer) with a thickness of 100 μm is treated once under the conditions of an output of 0.3 kW and a treatment speed of 3 m/min using a corona treatment device (AGF-B10, manufactured by Kasuga Denki Co., Ltd.). processed. The composition for forming a photo-alignment layer (1) was applied to the corona-treated surface by a bar coater, dried at 80° C. for 1 minute, and then irradiated with a polarized UV irradiation device (SPOT CURE SP-7; manufactured by Ushio Inc.). A photo-alignment layer was obtained by carrying out polarized UV exposure with an integrated amount of light of 100 mJ/cm ² . The thickness of the obtained photo-alignment layer was measured with a laser microscope (LEXT, manufactured by Olympus Corporation) and found to be 100 nm.

Subsequently, the composition for forming a liquid crystal layer (A-1) was applied onto the photo-alignment layer using a bar coater and dried at 120° C. for 1 minute. (manufactured by Denki Co., Ltd.) to irradiate ultraviolet rays (under nitrogen atmosphere, wavelength: 365 nm, irradiation intensity at wavelength 365 nm: 10 mW/cm ² , integrated light amount: 1000 mJ/cm ² ). 1 liquid crystal layer was formed to obtain a first liquid crystal layer (i) with a substrate layer (FIG. 1(a)). The thickness of the first liquid crystal layer was 2 μm.

(Production of first liquid crystal layer (ii) with substrate layer)
The first liquid crystal layer with a base layer (ii) was produced in the same procedure as the first liquid crystal layer with a base layer (i) except that the irradiation intensity of ultraviolet irradiation using a high-pressure mercury lamp was set to 50 mW / cm ² ) (Fig. 1(a)) was obtained. The thickness of the first liquid crystal layer was 2 μm.

(Production of first liquid crystal layer (iii) with substrate layer)
The ^first liquid crystal layer with a base layer (iii ) (Fig. 1(a)) was obtained. The thickness of the first liquid crystal layer was 2 μm.

(Production of second liquid crystal layer with substrate layer)
A polyethylene terephthalate (PET) film (second base layer) with a thickness of 38 μm is treated once with a corona treatment device (AGF-B10, manufactured by Kasuga Denki Co., Ltd.) under the conditions of an output of 0.3 kW and a treatment speed of 3 m/min. processed. The alignment layer-forming composition (2) was applied to the corona-treated surface by a bar coater and dried at 90° C. for 1 minute to obtain an alignment layer. The thickness of the resulting alignment layer was measured with a laser microscope (LEXT, manufactured by Olympus Corporation) and found to be 34 nm.

Subsequently, the composition for forming a liquid crystal layer (B-1) was applied onto the alignment layer using a bar coater and dried at 90° C. for 1 minute. (manufactured by Co., Ltd.) to form a second liquid crystal layer as a retardation layer by irradiating ultraviolet rays (under nitrogen atmosphere, wavelength: 365 nm, integrated light amount at wavelength 365 nm: 1000 mJ/cm ² ). A second liquid crystal layer with a material layer (FIG. 1(b)) was obtained. The thickness of the second liquid crystal layer was 1 μm.

[Preparation of optical film with separator]
A cyclic polyolefin film with a protective film (23 μm thick, ZF-14, manufactured by Nippon Zeon Co., Ltd.) having a length of 380 mm in the MD direction and a length of 180 mm in the TD direction (hereinafter sometimes referred to as “COP with a protective film”). Corona treatment (800 W, 10 m/min, bar width 700 mm, 1 pass) was performed on the cyclic polyolefin film surface opposite to the side. The corona-treated surface of the COP with the protective film and the exposed surface exposed by peeling off the first separator from the double-sided separator-attached adhesive layer prepared above were adhered using an automatic laminator HALTEC (manufactured by Sankyo Co., Ltd.). Together, an optical film with a separator was obtained.

[Measurement of TD curl of optical laminate]
The optical layered body with the substrate layer obtained in each example and each comparative example was allowed to stand for 24 hours in an environment with a temperature of 23° C. and a relative humidity of 55%. A protective film and a polyethylene terephthalate film (second substrate layer) having a thickness of 38 μm were peeled off from a rectangular cut piece having a thickness of 50 mm to obtain a test piece. The cut piece is cut out so that its long side forms an angle of 45 degrees with the TD direction of the optical laminate with the base layer (the TD direction of the second liquid crystal layer with the base layer and the first liquid crystal layer with the base layer). rice field.

After sufficiently removing the static electricity from the test piece, place it on a reference plane (horizontal table) with the concave surface of the test piece facing upward, and make the direction parallel to the TD direction out of the diagonals of the test piece. The height from the reference plane was measured for each of the two corners on a diagonal line close to each other. When the test piece is placed on the reference surface so that the cyclic polyolefin film (hereinafter sometimes referred to as "COP film") exposed by peeling off the protective film faces upward, the measured value is measured at the two corners of the test piece. When the curl is lifted, this curl is regarded as a positive curl, and the height of the corner from the reference plane is represented by a positive numerical value. On the other hand, if the test piece is placed on the reference plane so that the COP film side faces downward, and the above two corners of the test piece rise, this curl is called a reverse curl, and the height of the corner from the reference plane is a negative number. represented by A value obtained by averaging the numerical values measured for the two corners was taken as the TD curl value of the optical laminate.

The TD curl value of the optical film with a pressure-sensitive adhesive layer obtained by peeling off the protective film and the separator from the optical film with a separator was 0 when measured in the same procedure as above, so the TD curl value of the optical laminate was can be considered to be the same as the TD curl value of a laminate having a layer structure of first liquid crystal layer/first adhesive layer/second liquid crystal layer.

[Measurement of TD curl of first liquid crystal layer and second liquid crystal layer]
(Measurement of TD curl of auxiliary film for measurement)
The above optical film with a separator was used as an auxiliary film for measurement with a separator. After the auxiliary film for measurement with a separator was left for 24 hours in an environment with a temperature of 23° C. and a relative humidity of 55%, a rectangular piece with a long side length of 150 mm and a short side length of 50 mm was cut out. Then, the protective film and the second separator were peeled off to obtain a test piece of the auxiliary film for measurement. The cut-out piece was cut out in the same direction as the cut-out piece for measuring the TD curl of the first liquid crystal layer and the second liquid crystal layer, which will be described later.

After sufficiently removing the charge from the test piece of the auxiliary film for measurement, in the same procedure as above, among the diagonal lines of the test piece, the extension direction is set to the TD direction (first liquid crystal layer and second liquid crystal layer described later The same as the TD direction in the TD curl measurement) Measure the height from the reference plane of two corners on the diagonal line relatively close to the direction parallel to the direction, and take the average value as the TD curl value of the auxiliary film for measurement and The TD curl value of the auxiliary film for measurement was 0.0 mm.

(Measurement of TD curl of first liquid crystal layer and second liquid crystal layer)
The above optical film with a separator was used as an auxiliary film for measurement with a separator. The pressure-sensitive adhesive layer exposed by peeling off the second separator from this auxiliary film for measurement with a separator and the first liquid crystal layer of the first liquid crystal layer with each base layer obtained above are combined using an automatic laminating apparatus HALTEC. to obtain a first liquid crystal layer with an auxiliary film for measurement. After leaving the first liquid crystal layer with the auxiliary film for measurement under an environment of a temperature of 23° C. and a relative humidity of 55% for 24 hours, it was shaped into a rectangle with a long side length of 150 mm and a short side length of 50 mm. The protective film and the polyethylene terephthalate film (first base layer) are peeled off from the cut piece to obtain a laminate (a) (layer structure: cyclic polyolefin film/adhesive layer/first liquid crystal layer) as a test piece. ). The cut-out piece was cut out so that the long side formed an angle of 45 degrees with the TD direction of the first liquid crystal layer with the base layer.

After the obtained laminate (a) was sufficiently neutralized, two diagonal lines relatively close to the direction parallel to the TD direction, out of the diagonals of the laminate (a), were removed in the same procedure as described above. The height of the corners from the reference plane was measured, and the average value was taken as the TD curl value of the laminate (a). The difference between the TD curl value of the laminate (a) and the TD curl value of the auxiliary film for measurement obtained above was calculated as the curl value of the first liquid crystal layer. Table 1 shows the curl value of the first liquid crystal layer of the first liquid crystal layer with each base layer. “Cylindrical” in Table 1 means that the absolute value of the curl value of the first liquid crystal layer exceeds 20 mm because the laminate (a) was rolled into a cylindrical shape.

Laminate (b) (layer structure: COP film/adhesive layer) / second liquid crystal layer). The curl value of the second liquid crystal layer was calculated in the same manner as described above, except that the laminate (b) was used instead of the laminate (a). Table 1 shows the curl value of the second liquid crystal layer of the second liquid crystal layer with the base layer.

[Measurement of storage elastic modulus E]
The storage elastic modulus E [Pa] at a temperature of 30° C. when an active energy ray-curable adhesive was used as the first adhesive layer was calculated by the following procedure. On one side of a cyclic polyolefin resin film with a thickness of 50 μm, an active energy ray-curable adhesive was applied using a coating machine [bar coater, manufactured by Daiichi Rika Co., Ltd.], and the coated surface was further coated with a thickness of 50 μm. A cyclic polyolefin resin film was laminated. Next, the adhesive composition layer was cured by irradiating ultraviolet light with a "D bulb" manufactured by Fusion UV Systems Co., Ltd. so that the cumulative amount of light was 1500 mJ/cm ² (UVB). This was cut into a size of 5 mm×30 mm, and one cyclic polyolefin resin film was peeled off to obtain an adhesive cured layer with a resin film. This adhesive cured layer with a resin film is gripped with a gripper interval of 2 cm using a dynamic viscoelasticity measuring device "DVA-220" manufactured by IT Keisoku Co., Ltd. so that the long side is in the tensile direction. Then, the tension and contraction frequencies were set to 10 Hz, and the heating rate was set to 10°C/min to raise the temperature, and the storage elastic modulus E at a temperature of 30°C was determined.

[Measurement of thickness t]
The thickness t of the first adhesive layer (adhesive layer for bonding the first liquid crystal layer and the second liquid crystal layer) was measured using a contact film thickness gauge (Digimicrohead MH-15M, manufactured by Nikon Corporation) as follows. went like First, the film thickness of each of the first liquid crystal layer with the substrate layer and the second liquid crystal layer with the substrate layer was measured using the contact-type film thickness gauge. Next, for the liquid crystal layer laminate with double-sided substrate layers obtained by bonding the first liquid crystal layer with substrate layer and the second liquid crystal layer with substrate layer, the film thickness of which was measured, the second liquid crystal layer with substrate layer was measured. The film thickness was measured at the same positions as those of the first liquid crystal layer and the second liquid crystal layer with the substrate layer. From the difference between the measured thickness of the liquid crystal layer laminate with double-sided substrate layers and the total thickness of the first liquid crystal layer with substrate layers and the second liquid crystal layer with substrate layers, the thickness of the first adhesive layer t was calculated.

[Example 1]
Corona treatment (800 W, 10 m/min, bar width 700 mm, 1 pass) was applied to the surface on the second liquid crystal layer side of the second liquid crystal layer with the base layer prepared above (length 380 mm in MD direction × length 180 mm in TD direction). provided. The adhesive composition prepared above was used to form an adhesive composition layer using a coating machine (a bar coater manufactured by Daiichi Rika Co., Ltd.) to obtain a second liquid crystal layer with a composition layer. (Fig. 1(c)). Next, corona treatment was applied to the first liquid crystal layer side surface of the first liquid crystal layer (i) (length 380 mm in the MD direction × length 180 mm in the TD direction) with the substrate layer prepared above under the same conditions as above. , After bonding this corona-treated surface and the adhesive composition layer of the second liquid crystal layer with the composition layer using a bonding device (“LPA3301” manufactured by Fujipla Co., Ltd.) (Fig. 1(d) ), from the second substrate layer side of the second liquid crystal layer with the substrate layer, using an ultraviolet irradiation device with a belt conveyor (the lamp is “H bulb” manufactured by Fusion UV Systems), the irradiation intensity is 390 mW in the UVA region. /cm ² , an integrated light amount of 420 mJ/cm ² , and in the UVB range, 400 mW/cm ² , an integrated light amount of 400 mJ/cm ² . A liquid crystal layer laminate with base material layers on both sides was obtained (see FIG. 2(a)). The storage elastic modulus E and thickness t of the first adhesive layer, which is an adhesive cured layer obtained by curing the adhesive composition layer, were measured. 0.2 μm.

A polyethylene terephthalate film (first substrate layer) having a thickness of 100 μm was peeled off from the liquid crystal layer laminate with double-sided substrate layers to obtain a liquid crystal layer laminate with one-sided substrate layers (FIG. 2(b)). The exposed surface (photo-alignment layer) of the liquid crystal layer laminate with a single-sided substrate layer exposed by this peeling and the adhesive layer exposed by peeling the second separator from the optical film with separator prepared above are automatically pasted. They were laminated using a laminator HALTEC (manufactured by Sankyo Co., Ltd.) to obtain an optical laminate with a substrate layer (FIG. 4(a)). Using this optical layered body with a base material layer, the TD curl was measured according to the above procedure, and the TD curl value of the optical layered body was calculated. Table 1 shows the results.

[Example 2]
The same procedure as in Example 1, except that the adhesive composition was applied onto the second liquid crystal layer of the second liquid crystal layer with the base layer so that the thickness t of the first adhesive layer was 4.3 μm. Thus, a liquid crystal layer laminate with a substrate layer and an optical laminate with a substrate layer were obtained. The storage elastic modulus E of the first adhesive layer was 3000 MPa. In addition, using the obtained optical layered body with the substrate layer, the TD curl was measured according to the above procedure, and the TD curl value of the optical layered body was calculated. Table 1 shows the results.

[Example 3]
The same procedure as in Example 1, except that the adhesive composition was applied onto the second liquid crystal layer of the second liquid crystal layer with the base layer so that the thickness t of the first adhesive layer was 1.5 μm. Thus, a liquid crystal layer laminate with a substrate layer and an optical laminate with a substrate layer were obtained. The storage elastic modulus E of the first adhesive layer was 3000 MPa. In addition, using the obtained optical layered body with the substrate layer, the TD curl was measured according to the above procedure, and the TD curl value of the optical layered body was calculated. Table 1 shows the results.

[Example 4]
A liquid crystal layer with a base layer was prepared in the same manner as in Example 3 except that the first liquid crystal layer with a base layer (ii) prepared above was used instead of the first liquid crystal layer with a base layer (i). A laminate and an optical laminate with a substrate layer were obtained. The storage elastic modulus E of the first adhesive layer was 3000 MPa. In addition, using the obtained optical layered body with the substrate layer, the TD curl was measured according to the above procedure, and the TD curl value of the optical layered body was calculated. Table 1 shows the results.

[Example 5]
The same procedure as in Example 4, except that the adhesive composition was applied onto the second liquid crystal layer of the second liquid crystal layer with the base layer so that the thickness t of the first adhesive layer was 6.4 μm. Thus, a liquid crystal layer laminate with a substrate layer and an optical laminate with a substrate layer were obtained. The storage elastic modulus E of the first adhesive layer was 3000 MPa. In addition, using the obtained optical layered body with the substrate layer, the TD curl was measured according to the above procedure, and the TD curl value of the optical layered body was calculated. Table 1 shows the results.

[Comparative Example 1]
A liquid crystal layer with a base layer was prepared in the same manner as in Example 3 except that the first liquid crystal layer with a base layer (iii) prepared above was used instead of the first liquid crystal layer with a base layer (i). A laminate and an optical laminate with a substrate layer were obtained. The storage elastic modulus E of the first adhesive layer was 3000 MPa. In addition, using the obtained optical layered body with the substrate layer, the TD curl was measured according to the above procedure, and the TD curl value of the optical layered body was calculated. Table 1 shows the results.

As shown in Table 1, the optical layered bodies obtained in Examples 1 to 5 have suppressed reverse curling, and the optical layered bodies obtained in Examples 1 to 4 are in a flatter state. I understand. On the other hand, in Comparative Example 1, it can be seen that the reverse curl of the optical layered body is large.

10 first liquid crystal layer with substrate layer 11 first substrate layer 12 first liquid crystal layer 20 second liquid crystal layer with substrate layer 21 second substrate layer 22 second liquid crystal layer 25 composition layer second liquid crystal layer, 31 first adhesive layer, 31a adhesive composition layer, 32 second adhesive layer, 33 adhesive layer, 40 liquid crystal layer laminate with double-sided substrate layer (liquid crystal layer laminate), 41 single-sided substrate Liquid crystal layer laminate with material layer (liquid crystal layer laminate) 50 Second adhesive layer with release layer 51 First release layer 53 Second release layer 58 Adhesive layer with release layer 60 Optical film 61 Second Optical film with adhesive layer 70 Optical layered body with base layer peeled off (optical layered body) 71 Optical layered body with base layer (optical layered body) 72 Optical layered body with peeling layer (optical layered body) 73 Adhesion Optical layered body with agent layer (optical layered body).

Claims (18)

A method for manufacturing a liquid crystal layer laminate in which at least a first liquid crystal layer, a first adhesive layer, and a second liquid crystal layer are laminated in this order,
preparing a first liquid crystal layer with a base material layer, the first liquid crystal layer having a first base material layer and the first liquid crystal layer formed by polymerizing a polymerizable liquid crystal compound on the first base material layer;
preparing a second liquid crystal layer with a base layer, the second liquid crystal layer having a second base layer and the second liquid crystal layer formed by polymerizing a polymerizable liquid crystal compound on the second base layer;
laminating the second liquid crystal layer side of the second liquid crystal layer with the base layer on the first liquid crystal layer side of the first liquid crystal layer with the base layer via the first adhesive layer; including
The first adhesive layer is an adhesive cured layer made of a cured product of a curable adhesive,
the absolute value of the curl amount of the first liquid crystal layer is within 20 mm;
The manufacturing method of the liquid crystal layer laminate, wherein the absolute value of the amount of curl of the second liquid crystal layer is within 20 mm. When the storage elastic modulus of the first adhesive layer at a temperature of 30° C. is E [Pa] and the thickness is t [m], the following formula (1):
3000≦E×t≦15000 (1)
2. The manufacturing method of the liquid crystal layer laminate according to claim 1, wherein the relationship of 3. The method for producing a liquid crystal layer laminate according to claim 1, further comprising a step of peeling off said first substrate layer after said step of laminating. A liquid crystal layer laminate in which at least a first liquid crystal layer, a first adhesive layer, and a second liquid crystal layer are laminated in this order,
The first liquid crystal layer and the second liquid crystal layer are cured layers of a polymerizable liquid crystal compound,
The first adhesive layer is an adhesive cured layer made of a cured product of a curable adhesive,
the absolute value of the curl amount of the first liquid crystal layer is within 20 mm;
The liquid crystal layer laminate, wherein the absolute value of the amount of curl of the second liquid crystal layer is within 20 mm. When the storage elastic modulus of the first adhesive layer at a temperature of 30° C. is E [Pa] and the thickness is t [m], the following formula (1):
3000≦E×t≦15000 (1)
5. The liquid crystal layer laminate according to claim 4, which satisfies the relationship: 6. The liquid crystal layer laminate according to claim 4, further comprising a second substrate layer on the side opposite to the first adhesive layer of the second liquid crystal layer. 7. The liquid crystal layer laminate according to claim 6, further comprising a first substrate layer on the opposite side of said first liquid crystal layer to said first adhesive layer. A method for producing an optical laminate in which at least an optical film, a second adhesive layer, a first liquid crystal layer, a first adhesive layer, and a second liquid crystal layer are laminated in this order,
The first exposed surface side exposed by peeling off the first substrate layer from the liquid crystal layer laminate manufactured by the method for manufacturing a liquid crystal layer laminate according to claim 3, the liquid crystal layer laminate according to claim 7. A second adhesive layer and an optical film are provided on the first exposed surface side exposed by peeling the first base layer from the body or on the first liquid crystal layer side of the liquid crystal layer laminate according to claim 6. A method for manufacturing an optical laminate, including the step of laminating in this order. 9. The method for producing an optical layered body according to claim 8, further comprising a step of peeling off the second substrate layer after the step of laminating the second adhesive layer and the optical film in this order. Furthermore, a step of preparing an adhesive layer with a release layer in which an adhesive layer and a release layer are laminated;
and laminating the pressure-sensitive adhesive layer side of the pressure-sensitive adhesive layer with a release layer on the second exposed surface side exposed by peeling the second base layer. body manufacturing method. 11. The method for producing an optical layered body according to claim 10, further comprising a step of peeling off the release layer after the step of laminating the pressure-sensitive adhesive layer side of the pressure-sensitive adhesive layer with a release layer. The method for producing an optical laminate according to any one of claims 8 to 11, wherein the optical film includes a polarizing plate. An optical laminate in which at least an optical film, a second adhesive layer, a first liquid crystal layer, a first adhesive layer, and a second liquid crystal layer are laminated in this order,
The first liquid crystal layer and the second liquid crystal layer are cured layers of a polymerizable liquid crystal compound,
The first adhesive layer is an adhesive cured layer made of a cured product of a curable adhesive,
the absolute value of the curl amount of the first liquid crystal layer is within 20 mm;
The optical layered body, wherein the absolute value of the amount of curl of the second liquid crystal layer is within 20 mm. When the storage elastic modulus of the first adhesive layer at a temperature of 30° C. is E [Pa] and the thickness is t [m], the following formula (1):
3000≦E×t≦15000 (1)
14. The optical laminate according to claim 13, which satisfies the relationship of 15. The optical laminate according to claim 13, further comprising a second substrate layer on the side of the second liquid crystal layer opposite to the first adhesive layer. 15. The optical laminate according to claim 13, further comprising an adhesive layer on the side of the second liquid crystal layer opposite to the first adhesive layer. 17. The optical laminate according to claim 16, further comprising a release layer on the side of the pressure-sensitive adhesive layer opposite to the second liquid crystal layer. The optical laminate according to any one of claims 13 to 17, wherein the optical film comprises a polarizing plate.

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