JP7399756B2 - Optical laminate and its manufacturing method - Google Patents

Description

The present invention relates to an optical laminate and a method for manufacturing the same.

Organic EL display devices using organic light emitting diodes (OLEDs) are not only lighter and thinner than liquid crystal display devices, but also offer high image quality such as wide viewing angles, fast response speeds, and high contrast. Because it can be realized, it is used in various fields such as smartphones, televisions, and digital cameras. In organic EL display devices, it is known that a circularly polarizing plate or the like is used to improve antireflection performance in order to suppress deterioration in visibility due to reflection of external light.

For example, in Patent Documents 1 and 2, as an optical laminate having an antireflection function applied to an image display panel such as an organic EL display device, a polarizing plate including a linearly polarizing layer is formed with a liquid crystal compound and an adhesive layer is attached to each other. An optical laminate having a structure in which two retardation layers are laminated with each other interposed therebetween is disclosed. Patent Document 2 discloses that two laminates in which an alignment film and a retardation layer are formed on a base material layer are prepared, and after bonding the retardation layer sides of the two laminates together with an adhesive layer, one of the laminates is bonded with an adhesive layer. It is described that a material layer is peeled off, a polarizing plate is bonded via an adhesive layer, and then the other base layer is peeled off to produce an optical laminate. Patent Document 3 discloses that a retardation layer such as a λ/4 plate formed using a liquid crystal compound is provided on a transparent support (base material layer), and the retardation layer provided on this transparent support is It is disclosed that a circularly polarizing plate is manufactured by transferring to a polarizing plate.

Japanese Patent Application Publication No. 2017-102286 JP 2015-40953 Publication Japanese Patent Application Publication No. 2015-187717

In the retardation layer formed using a liquid crystal compound as described in Patent Documents 1 to 3, a laminate in which a retardation layer is formed on a base material layer is prepared, and a circularly polarizing plate is formed using this laminate. May be manufactured. In this case, after laminating the retardation layer side of the laminate with a polarizing plate, the base material layer of the laminate is separated, and the retardation layer is transferred to the polarizing plate to produce a circularly polarizing plate. .

However, if the base material layer is separated after laminating the polarizing plate and the retardation layer laminate, cracks may occur in the retardation layer or the base material layer may crack depending on the speed at which the base material layer is separated (separation speed). Problems such as breakage may occur.

The present invention provides an optical laminate and a method for manufacturing the same, in which the base layer can be easily separated regardless of the separation speed of the base layer when the base layer is separated during the production of the optical laminate. .

The present invention provides the following optical laminate and manufacturing method.
[1] An optical laminate comprising an optical film, an adhesive layer, and a retardation layer-containing layer including a retardation layer (X) in this order,
The retardation layer (X) is
disposed at the farthest position from the adhesive layer in the retardation layer-containing layer,
It includes a liquid crystal layer (X) which is a cured product layer of a polymerizable liquid crystal compound, and
An optical laminate having a puncture modulus E(X) of 15 g/mm or less.
[2] The retardation layer (X) is a laminate of a liquid crystal layer (X) and an alignment layer (X),
The optical laminate according to [1], wherein the alignment layer (X) is provided on a side of the liquid crystal layer (X) opposite to the adhesive layer side.
[3] Further, a base material layer (X) is provided on the side opposite to the adhesive layer side of the retardation layer (X),
The optical laminate according to [1] or [2], wherein the base layer (X) is separably provided between the base layer (X) and the liquid crystal layer (X).
[4] The retardation layer-containing layer includes a first retardation layer, a bonding layer, and a second retardation layer in this order from the adhesive layer side,
The first retardation layer includes a first liquid crystal layer that is a cured layer of a polymerizable liquid crystal compound,
The optical laminate according to any one of [1] to [3], wherein the second retardation layer is the retardation layer (X).
[5] The optical laminate according to any one of [4], wherein the first retardation layer is a laminate of the first liquid crystal layer and a first alignment layer.
[6] The optical laminate according to [4] or [5], wherein the first retardation layer has a puncture modulus E1 of 15 g/mm or less.
[7] The optical laminate according to any one of [4] to [6], wherein the bonding layer is a cured adhesive layer.
[8] The optical laminate according to any one of [1] to [3], wherein the retardation layer-containing layer is the retardation layer (X).
[9] The optical laminate according to any one of [1] to [8], wherein the adhesive layer has a storage modulus of 3.0×10 ⁶ N/m ² or less at a temperature of 23° C.
[10] The optical laminate according to any one of [1] to [9], wherein the adhesive layer has a storage modulus of 6.0×10 ⁵ N/m ² or less at a temperature of 80° C.
[11] The optical laminate according to any one of [1] to [10], wherein the optical film includes a polarizing plate in which a protective layer is provided on one or both sides of a linearly polarizing layer.
[12] A method for producing an optical laminate comprising an optical film, an adhesive layer, and a retardation layer-containing layer including a retardation layer (X) in this order,
A step of preparing a base layer-attached retardation layer (X) having a base layer (X) and the retardation layer (X);
Using the optical film, the adhesive layer, and the base layer-attached retardation layer (X), the optical film, the adhesive layer, the retardation layer-containing layer, and the base layer (X ) in this order;
Peeling the base layer (X) from the laminate,
The retardation layer (X) is
disposed at the farthest position from the adhesive layer in the retardation layer-containing layer,
A liquid crystal layer (X) formed by polymerizing a polymerizable liquid crystal compound on the base layer (X), and
A method for producing an optical laminate having a puncture modulus E(X) of 15 g/mm or less.
[13] The retardation layer-containing layer includes a first retardation layer, a bonding layer, and a second retardation layer in this order from the adhesive layer side,
The first retardation layer includes a first liquid crystal layer formed by polymerizing a polymerizable liquid crystal compound on a first base layer,
The method for manufacturing an optical laminate according to [12], wherein the second retardation layer is the retardation layer (X).
[14] The step of preparing the laminate includes:
preparing a first retardation layer with a base material layer having the first base layer and the first retardation layer;
The first retardation layer side of the first retardation layer with a base material layer and the retardation layer (X) side of the retardation layer with a base material layer (X) are bonded via the bonding layer. The process of matching,
A step of separating the first base material layer after the step of laminating via the laminating layer;
The method for producing an optical laminate according to [13], comprising the step of bonding the exposed surface exposed by separating the first base layer and the optical film via the adhesive layer. .
[15] The step of preparing the laminate includes:
preparing a first retardation layer with a base material layer having the first base layer and the first retardation layer;
bonding the optical film and the first retardation layer side of the first retardation layer with a base material layer via an adhesive layer;
A step of separating the first base layer after the step of bonding via the adhesive layer,
A step of laminating the exposed surface exposed by separating the first base layer and the retardation layer (X) side of the base layer-attached retardation layer (X) via the lamination layer. The method for producing an optical laminate according to [13], comprising:
[16] The method for producing an optical laminate according to [15], wherein the first retardation layer has a puncture modulus E1 of 15 g/mm or less.
[17] The first retardation layer with a base layer has a first alignment layer between the first base layer and the first liquid crystal layer, according to any one of [14] to [16]. A method for manufacturing an optical laminate.
[18] The retardation layer-containing layer is the retardation layer (X),
The step of preparing the laminate includes:
The optical system according to [12], comprising a step of laminating the optical film and the retardation layer (X) side of the base layer-attached retardation layer (X) via the adhesive layer. Method for manufacturing a laminate.
[19] The retardation layer with a base material layer (X) has an alignment layer between the base material layer (X) and the liquid crystal layer (X), according to any one of [12] to [18]. The method for manufacturing the optical laminate described above.

According to the present invention, when separating the base material layer during the production of an optical laminate, etc., the base material layer can be easily separated regardless of the separation speed of the base material layer.

1 is a schematic cross-sectional view schematically showing an example of an optical laminate according to a first embodiment of the present invention. It is a schematic sectional view showing typically an example of the modification of the optical layered product of a 1st embodiment of the present invention. 1 is a schematic cross-sectional view schematically showing an example of an optical laminate having a base material layer of the present invention. It is a schematic sectional view showing typically an example of the modification of the optical layered product which has a base material layer of the present invention. FIG. 1 is a schematic cross-sectional view schematically showing an example of the manufacturing process of the optical laminate according to the first embodiment of the present invention. It is a schematic sectional view showing typically another example of the manufacturing process of the optical layered product of a 1st embodiment of the present invention. It is a schematic sectional view showing typically an example of an optical layered product of a 2nd embodiment of the present invention. 1 is a schematic cross-sectional view schematically showing an example of an optical laminate having a base material layer of the present invention.

Hereinafter, preferred embodiments of the optical laminate of the present invention and its manufacturing method will be described with reference to the drawings.

<Optical laminate and its manufacturing method>
The optical laminate of this embodiment includes an optical film, an adhesive layer, and a retardation layer-containing layer including a retardation layer (X) in this order. The retardation layer (X) is disposed at the farthest position from the adhesive layer in the retardation layer-containing layer, includes a liquid crystal layer that is a cured product layer of a polymerizable liquid crystal compound, and has a puncture modulus E (X) is 15 g/mm or less. The optical laminate may further include a base material layer (X) on the side opposite to the pressure-sensitive adhesive layer side of the retardation layer-containing layer.

The retardation layer-containing layer may be anything that includes the retardation layer (X), for example, it may be the retardation layer (X) itself, or the retardation layer (X) and the retardation layer (X). It may also contain other retardation layers. The number of other retardation layers included in the retardation-containing layer is preferably one layer, may be two or more layers, and is usually five or less layers, and may be three or less layers. When the retardation layer-containing layer includes another retardation layer, the retardation layer-containing layer includes the retardation layer (X), one or more other retardation layers, and the retardation layer (X) and other retardation layers. It is preferable that it is a laminate including one or more bonding layers for bonding between a retardation layer or other retardation layers. When the retardation layer-containing layer includes another retardation layer, the retardation layer (X) is disposed at the farthest position from the adhesive layer in the lamination direction of the optical laminate, and is separated from the adhesive layer of the optical laminate. Another retardation layer is arranged between the retardation layer (X) and the retardation layer (X). The retardation layer-containing layer is a laminate of a retardation layer (X) and another retardation layer (first embodiment described later), or is the retardation layer (X) itself (a second embodiment described later). embodiment) is preferred.

In the optical laminate described above, the puncture elastic modulus E(X) of the retardation layer (X) is within the above range. It is considered that the smaller the puncture elastic modulus E(X) of the retardation layer (X), the softer the retardation layer (X) becomes. As described below, the optical laminate can be obtained by separating the base layer (X). When the puncture elastic modulus E(X) of the retardation layer (X) becomes smaller, the retardation layer (X) will more easily follow the movement of peeling off the base layer (X), so the separation of the base layer (X) will be easier. It is considered that the base material layer (X) can be easily separated regardless of the speed.

The method for manufacturing an optical laminate of this embodiment is the method for manufacturing an optical laminate described above,
A step of preparing a base layer-attached retardation layer (X) having a base layer (X) and a retardation layer (X);
A laminate including an optical film, an adhesive layer, a retardation layer with a base layer (X), and an optical film, an adhesive layer, a retardation layer-containing layer, and a base layer (X) in this order. a process of preparing;
The method includes a step of peeling the base material layer (X) from the laminate.

Hereinafter, the optical laminate and its manufacturing method will be specifically explained by giving specific examples. In the optical laminate and the manufacturing method thereof of the first embodiment, the retardation layer-containing layer is a retardation laminate including a first retardation layer and a second retardation layer, and the second retardation layer is the retardation layer containing the retardation layer. This corresponds to the layer (X), and the base layer-attached retardation layer (X) corresponds to the base layer-attached second retardation layer. In the optical laminate and its manufacturing method of the second embodiment, a case where the retardation layer-containing layer is the retardation layer (X) itself will be described.

(Optical laminate of first embodiment)
1 to 4 are schematic cross-sectional views schematically showing an example of an optical laminate according to this embodiment (first embodiment). As shown in FIGS. 1 to 4, the optical laminates 1a, 1b, 1c, and 1d (hereinafter, these may be collectively referred to as "optical laminates 1") of the present embodiment include an optical film 40, an adhesive It includes the agent layer 31, the first retardation layer 10, the bonding layer 32, and the second retardation layer 20 (retardation layer (X)) in this order. The first retardation layer 10, the bonding layer 32, and the second retardation layer 20 constitute a retardation layer-containing layer. The first retardation layer 10 includes a first liquid crystal layer 12 that is a cured layer of a polymerizable liquid crystal compound. The second retardation layer 20 includes a second liquid crystal layer 22 (liquid crystal layer (X)) that is a cured layer of a polymerizable liquid crystal compound. The piercing elastic modulus E2 (piercing elastic modulus E(X)) of the second retardation layer 20 is 15 g/mm or less.

As shown in FIGS. 3 and 4, the optical laminate 1 has a second base layer 25 (base layer (X)) on the side opposite to the bonding layer 32 side of the second retardation layer 20. You can leave it there. It is preferable that the second base layer 25 is separably provided between the second base layer 25 and the second liquid crystal layer 22 included in the second retardation layer 20 .

Separable between the second base material layer 25 and the second liquid crystal layer 22 means that the second base material layer 25 is separable from the second liquid crystal layer 22, or that the second base material layer 25 is separable from the second liquid crystal layer 22. If the second alignment layer 21 exists between the second alignment layer 22 and the second alignment layer 22, the second alignment layer 21 should be peelable from the second alignment layer 21, or the second alignment layer 21 should be peelable from the second liquid crystal layer 22. It means that it is removable. Therefore, when the second base layer 25 is removable from the second alignment layer 21, when the second base layer 25 is separated from the optical laminates 1c and 1d (FIGS. 3 and 4), , the second alignment layer 21 remains on the second liquid crystal layer 22 (FIGS. 1 and 2). When the second alignment layer 21 is removable from the second liquid crystal layer 22, when the second base layer 25 is separated from the optical laminate 1a, the second alignment layer 21 and the second base layer 25 are separated from each other. 21 is peeled off.

The first retardation layer 10 may be the first liquid crystal layer 12 itself, which is a cured layer of a polymerizable liquid crystal compound, or may be a laminate of the first liquid crystal layer 12 and the first alignment layer 11. . When the first retardation layer 10 has the first alignment layer 11, the first alignment layer 11 may be provided on the side opposite to the second retardation layer 20 side of the first liquid crystal layer 12 (see FIG. ) may be provided on the second retardation layer 20 side of the first liquid crystal layer 12 (FIG. 2).

The puncture elastic modulus E1 of the first retardation layer 10 is not particularly limited, but may be, for example, 50 g/mm or less, 40 g/mm or less, 30 g/mm or less, It may be 20 g/mm or less, preferably 15 g/mm or less, 12 g/mm or less, 10 g/mm or less, or 9 g/mm or less. The puncture elastic modulus E1 is usually 3 g/mm or more, 5 g/mm or more, may be 7 g/mm or more, and may be 10 g/mm or more. The puncture elastic modulus E1 is a value at a temperature of 23° C. and a relative humidity of 50%, and can be measured according to the procedure of the method for measuring the puncture elastic modulus described in the Examples below. When the first retardation layer 10 is a laminate of the first liquid crystal layer 12 and the first alignment layer 11, the piercing elastic modulus E1 of the first retardation layer 10 is determined by a needle piercing from the first alignment layer 11 side. Measure. In the first retardation layer 10, the temperature dependence of the puncture elastic modulus E1 is not observed in the range of 23 to 80°C.

In the optical laminates 1b and 1d (FIGS. 2 and 4), the puncture elastic modulus E1 of the first retardation layer 10 is preferably 15 g/mm or less, may be 12 g/mm or less, and 10 g /mm or less, or 9 g/mm or less. The piercing elastic modulus E2 is usually 3 g/mm or more, may be 5 g/mm or more, or may be 7 g/mm or more.

The puncture elastic modulus E1 of the first retardation layer 10 is determined by, for example, the type and degree of polymerization (curing degree) of the polymerizable liquid crystal compound constituting the first liquid crystal layer 12, the polymerization initiator contained in the first liquid crystal layer 12, Types and amounts of additives such as reactive additives, leveling agents, polymerization inhibitors, crosslinking agents, etc., types and degree of polymerization (cure degree) of polymerizable compounds in the curable resin composition constituting the first alignment layer 11 , the thickness of the first retardation layer 10, etc. can be adjusted. Generally, as the degree of polymerization (degree of curing) increases, the value of the puncture elastic modulus E1 also increases. Further, the puncture elastic modulus E1 of the first retardation layer 10 can also be adjusted by the crosslink density of the first liquid crystal layer 12 and the crosslink density of the first alignment layer 11. For example, in order to increase the crosslink density of 12 in the first liquid crystal layer, it is necessary to use a polyfunctional polymerizable compound having three or more polymerizable groups in the molecule as a polymerizable liquid crystal compound for forming the first liquid crystal layer 12. A liquid crystal compound may be used.

In order to set the puncture elastic modulus E1 of the first retardation layer 10 within a predetermined range, for example, the degree of polymerization (degree of hardening) of the polymerizable liquid crystal compound and the degree of polymerization (degree of hardening) of the first alignment layer 11 are controlled. Preliminary experiments can be conducted to obtain a desired piercing elastic modulus E1. As such a preliminary experiment, for example, when controlling the degree of polymerization of the first liquid crystal layer, it can be carried out as follows. First, a coating layer of a composition for forming a liquid crystal layer containing a polymerizable liquid crystal compound is provided on the first base layer (which may include a first alignment layer), and this coating layer is irradiated with ultraviolet rays or the like. Then, a first liquid crystal layer is formed on the first base layer. The ratio (relative value) between the amount of polymerizable groups in the polymerizable liquid crystal compound contained in the coating layer and the amount of polymerizable groups in the polymerizable liquid crystal compound contained in the first liquid crystal layer is The degree of polymerization (degree of curing) is determined by measuring by IR) spectrum measurement or the like. The puncture elastic modulus E1 of the first retardation layer including the first liquid crystal layer obtained at this time is measured, and the degree of polymerization determined above is correlated with the puncture elastic modulus E1. This procedure is performed by changing the type of polymerizable liquid crystal compound, the amount of irradiation of ultraviolet rays, etc. By obtaining the correlation between the degree of polymerization and the puncture elastic modulus E1 in this way, it is possible to determine the degree of polymerization for obtaining the desired puncture elastic modulus E1.

The thickness of the first retardation layer 10 is preferably 1.0 μm or more, more preferably 1.5 μm or more, may be 1.7 μm or more, or may be 2.0 μm or more. . The thickness of the first retardation layer 10 is usually 8 μm or less, may be 5 μm or less, or may be 3 μm or less.

The second retardation layer 20 may be the second liquid crystal layer 22 itself, which is a cured layer of a polymerizable liquid crystal compound, or may be a laminate of the second liquid crystal layer 22 and the second alignment layer 21. . When the second retardation layer 20 has the second alignment layer 21, the second alignment layer 21 is provided on the side of the second liquid crystal layer 22 opposite to the first retardation layer 10 side.

The puncture modulus E2 of the second retardation layer 20 is 15 g/mm or less, may be 12 g/mm or less, may be 10 g/mm or less, or may be 9 g/mm or less . The piercing elastic modulus E2 is usually 3 g/mm or more, may be 5 g/mm or more, or may be 7 g/mm or more. The puncture modulus E2 is a value at a temperature of 23° C. and a relative humidity of 50%, and can be measured by the method for measuring the puncture modulus described in the Examples below. When the second retardation layer 20 is a laminate of the second liquid crystal layer 22 and the second alignment layer 21, the piercing elastic modulus E2 of the second retardation layer 20 is determined by a needle piercing from the second alignment layer 21 side. Measure. In the second retardation layer 20, similarly to the first retardation layer 10, the temperature dependence of the puncture elastic modulus E2 is not observed in the range of 23 to 80°C.

The puncture elastic modulus E2 of the second retardation layer 20 is determined by, for example, the type and degree of polymerization (curing degree) of the polymerizable liquid crystal compound constituting the second liquid crystal layer 22, the polymerization initiator contained in the second liquid crystal layer 22, Types and amounts of additives such as reactive additives, leveling agents, polymerization inhibitors, crosslinking agents, etc., types and degree of polymerization (cure degree) of polymerizable compounds in the curable resin composition constituting the second alignment layer 21 , the thickness of the second retardation layer 20, etc. can be adjusted. Generally, as the degree of polymerization (degree of curing) increases, the value of the puncture elastic modulus E2 also increases. Further, the puncture elastic modulus E2 of the second retardation layer 20 can also be adjusted by the crosslink density of the second liquid crystal layer 22 and the crosslink density of the second alignment layer 21. For example, in order to increase the crosslink density of 22 in the second liquid crystal layer, a polyfunctional polymerizable compound having three or more polymerizable groups in the molecule is used as a polymerizable liquid crystal compound for forming the second liquid crystal layer 22. A liquid crystal compound may be used.

As a preliminary experiment method to set the puncture elastic modulus E2 of the second retardation layer 20 within a predetermined range, the above-mentioned method is carried out to set the puncture elastic modulus E1 of the first retardation layer within a desired range. A method similar to the method of the preliminary experiment can be mentioned.

The thickness of the second retardation layer 20 is preferably 1.0 μm or more, may be 1.5 μm or more, may be 2.0 μm or more, or may be 2.5 μm or more. The thickness is usually 8 μm or less, may be 5 μm or less, may be 3.5 μm or less, or may be 3.0 μm or less.

It is considered that the smaller the puncture elastic modulus E2 of the second retardation layer 20, the softer the second retardation layer 20 becomes. As described later, the optical laminates 1a and 1b can be obtained by separating the second base material layer 25 from the optical laminates 1c and 1d. When the puncture elastic modulus E2 of the second retardation layer 20 becomes smaller, the second retardation layer 20 easily follows the movement of peeling off the second base layer 25, so regardless of the separation speed of the second base layer 25, It is thought that the second base material layer 25 can be easily separated. On the other hand, when the puncture elastic modulus E2 increases, the second retardation layer 20 becomes harder, and it is considered that the second retardation layer 20 becomes difficult to follow the movement of peeling off the second base layer 25. Therefore, depending on the separation speed of the second base material layer 25, problems such as cracks occurring in the second retardation layer 20 or breakage of the second base material layer 25 may occur when the second base material layer 25 is separated. There is a possibility that this may occur.

In the optical laminate 1, since the puncture modulus E2 of the second retardation layer 20 is within the above range, the second base layer 25 can be separated well regardless of the separation speed of the second base layer 25. Cheap. In particular, it is possible to suppress the peeling force required to separate the second base layer 25 from greatly varying depending on the separation speed of the second base layer 25. On the other hand, if the puncture elastic modulus E2 of the second retardation layer 20 is not within the above range, the peeling force will vary greatly depending on the separation speed of the second base layer 25, and depending on the separation speed, the above-mentioned There is a possibility that a problem may occur.

The puncture elastic modulus E2 of the second retardation layer 20 may be the same as or different from the puncture elastic modulus E1 of the first retardation layer 10. By setting the puncture elastic modulus E2 of the second retardation layer 20 within the above range, the second base material layer 25 can be easily separated regardless of the separation speed, so that the puncture elasticity E2 of the first retardation layer 10 can be easily separated. The elastic modulus E1 may be larger than the piercing elastic modulus E2 of the second retardation layer 20.

In particular, in the optical laminates 1b and 1d, it is preferable that the puncture elastic modulus E1 of the first retardation layer 10 is also 15 g/mm or less. It is considered that the smaller the puncture elastic modulus E1 of the first retardation layer 10, the softer the first retardation layer 10 becomes. As will be described later, in the manufacturing process of the optical laminate 1b, a third laminate 63 (FIG. 6) having an optical film 40, an adhesive layer 31, a first retardation layer 10, and a first base layer 15 in this order is used. The process includes a step of separating the first base material layer 15 from the base material layer 15. When the piercing elastic modulus E1 of the first retardation layer 10 becomes smaller, the first retardation layer 10 becomes easier to follow the movement of peeling off the first base layer 15, so regardless of the separation speed of the first base layer 15, It is thought that the first base material layer 15 can be easily separated. On the other hand, when the puncture elastic modulus E1 increases, the first retardation layer 10 becomes harder, and it is considered that the first retardation layer 10 becomes difficult to follow the movement of peeling off the first base layer 15. Therefore, depending on the separation speed of the first base layer 15, problems such as cracks occurring in the first retardation layer 10 or breakage of the first base layer 15 may occur when the first base layer 15 is separated. There is a possibility that this may occur.

In the optical laminates 1b and 1d, by setting the puncture elastic modulus E1 of the first retardation layer 10 to 15 g/mm or less, it is possible to suppress the peeling force from greatly varying depending on the separation speed of the first base layer 15. Therefore, it is considered that the first base material layer 15 can be easily separated from the third laminate 63 (FIG. 6), which will be described later, regardless of the separation speed.

The adhesive layer 31 is a layer for bonding the optical film 40 and the first retardation layer 10, and is a layer formed using an adhesive composition. The adhesive layer 31 can be in direct contact with the optical film 40 and the first retardation layer 10.

The storage elastic modulus of the adhesive layer 31 at a temperature of 23° C. is preferably 3.0×10 ⁶ N/m ² or less, and may be 2.5×10 ⁶ N/m ² or less, 2. It may be 0×10 ⁶ N/m ² or less, 1.0×10 ⁶ N/m ² or less, or 5×10 ⁵ N/m ² or less. The storage elastic modulus of the adhesive layer 31 at a temperature of 23° C. is usually 1×10 ⁵ N/m ² or more, and may be 2×10 ⁵ N/m ² or more. The storage modulus at a temperature of 23° C. can be measured by the method described in Examples below.

It is considered that because the storage elastic modulus of the adhesive layer 31 at a temperature of 23° C. is within the above range, the adhesive layer 31 can easily follow the movement of peeling off the second base layer 25. Thereby, the second base layer 25 can be easily separated from the optical laminates 1c and 1d regardless of the separation speed of the second base layer 25. On the other hand, if the storage elastic modulus of the adhesive layer 31 at a temperature of 23° C. is not within the above range, the adhesive layer 31 becomes difficult to follow the movement of peeling off the second base layer 25, and the second base layer 25 Depending on the separation speed, problems such as cracking in the second retardation layer 20 or breakage of the second base layer 25 may occur when the second base layer 25 is separated.

The storage elastic modulus of the adhesive layer 31 at a temperature of 80° C. is preferably 6.0×10 ⁵ N/m ² or less, and may be 5.0×10 ⁵ N/m ² or less; 3. It may be 0×10 ⁵ N/m ² or less, 1.0×10 ⁵ N/m ² or less, or 8×10 ⁴ N/m ² or less. The storage elastic modulus of the adhesive layer 31 at a temperature of 80° C. is usually 1×10 ⁴ N/m ² or more, and may be 3×10 ⁴ N/m ² or more, and 5×10 ⁴ N/m It may be ² or more. The storage modulus at a temperature of 80°C can be measured by the method described in the Examples below.

Since the storage elastic modulus of the adhesive layer 31 at a temperature of 80°C is within the above range, the storage elastic modulus of the second base layer 25 is The second base material layer 25 can be easily separated from the optical laminates 1c and 1d regardless of the separation speed.

The storage modulus of the adhesive layer 31 at a temperature of 23° C. and a temperature of 80° C. can be adjusted depending on the type of adhesive contained in the adhesive composition, and when the adhesive is an active energy ray-curable adhesive, It can be adjusted by adjusting the degree of hardening by irradiation with energy rays.

The optical film 40 includes a linear polarizing layer; a polarizing plate having a protective layer on one or both sides of the linear polarizing layer; a polarizing plate with a protective film having a protective film on one side of the polarizing plate; a reflective film; a transflective film. Examples include films; brightness-enhancing films; optical compensation films; films with anti-glare functions; one type or a combination of two or more of these may be used. The optical film 40 preferably includes at least a linearly polarizing layer, and more preferably includes a polarizing plate. When the optical film 40 includes a polarizing plate having a protective layer only on one side of the linearly polarizing layer, it is preferable that the linearly polarizing layer side of the polarizing plate and the first retardation layer 10 are bonded together. When the optical film has a polarizing plate with a protection film, it is preferable that the polarizing plate side of the polarizing plate with a protection film and the first retardation layer 10 are bonded together.

The bonding layer 32 is a layer for bonding the first retardation layer 10 and the second retardation layer 20. The bonding layer 32 can be in direct contact with the first retardation layer 10 and the second retardation layer 20. The bonding layer 32 can be an adhesive layer or a cured adhesive layer, and is preferably a cured adhesive layer.

The optical laminate 1 may be a circularly polarizing plate. In this case, the optical film 40 includes a linearly polarizing layer, a polarizing plate, or a polarizing plate with a protection film, and at least one of the first retardation layer 10 and the second retardation layer 20 has a 1/4 wavelength retardation layer. Preferably, it is a layer. When the optical laminate 1 is a circularly polarizing plate, the layer structure of the optical laminate 1 is, when the optical film 40 is a polarizing plate, [i] polarizing plate, 1/2 wavelength retardation layer, 1/4 wavelength It has a retardation layer in this order, [ii] it has a polarizing plate, a quarter wavelength retardation layer with reverse wavelength dispersion, and a positive C plate in this order, or [iii] it has a polarizing plate, a positive C plate, and a reverse wavelength dispersion Examples include those having 1/4 wavelength retardation layers of different wavelengths in this order.

The optical laminate 1 can be used by being attached to an image display element of a liquid crystal display device or an organic EL (electroluminescence) display device, for example.

(Method for manufacturing optical laminate of first embodiment)
5 and 6 are schematic cross-sectional views schematically showing an example of the manufacturing process of the optical laminate of this embodiment (first embodiment). Optical laminates 1a and 1b manufactured by the method for manufacturing optical laminate 1 include the optical film 40, adhesive layer 31, first retardation layer 10, bonding layer 32, and second retardation layer described above. 20 in this order. The second retardation layer 20 has the piercing elastic modulus E2 (piercing elastic modulus E(X)) described above. It is preferable that the adhesive layer 31 has the storage modulus at a temperature of 23° C. and a temperature of 80° C. as described above.

The method for manufacturing the optical laminates 1a and 1b is as follows:
A step of preparing a first retardation layer with a base material layer 18 having a first base material layer 15 and a first retardation layer 10, ((a) of FIG. 5)
A second retardation layer with a base material layer 28 (a retardation layer with a base material layer) having a second base material layer 25 (a base material layer (X)) and a second retardation layer 20 (a retardation layer (X)) (X)) (FIG. 5(b)),
A step of preparing a laminate having an optical film 40, an adhesive layer 31, a first retardation layer 10, a bonding layer 32, a second retardation layer 20, and a second base layer 25 in this order;
The step of separating the second base material layer 25 from the laminate is included. The first retardation layer 10, the bonding layer 32, and the second retardation layer 20 constitute a retardation layer-containing layer.

The method for manufacturing the optical laminate 1 further includes a step of forming another adhesive layer other than the adhesive layer 31 and a release film in order from the exposed surface side exposed by the step of separating the second base layer 25. May contain. Other pressure-sensitive adhesive layers can be used, for example, for bonding to an image display element of a display device. The release film can cover and protect the surface of the other adhesive layer on the side opposite to the second retardation layer 20 side, and can be provided so as to be removable from the other adhesive layer.

In the method for manufacturing the optical laminate 1, the second retardation layer 20 has a puncture modulus E2 within the range described above. Therefore, even when the second base layer 25 is separated, problems such as cracking in the second retardation layer 20 or breakage of the second base layer 25 can be suppressed, and the second base layer 25 can be separated. The material layer 25 can be separated easily.

The method for manufacturing the optical laminate 1 includes the steps described above, but in the case of obtaining the optical laminate 1a shown in FIG. 1 and the case of obtaining the optical laminate 1b shown in FIG. The processes involved are different. When obtaining the optical laminate 1a shown in FIG. 1, the puncture modulus E1 of the first retardation layer 10 is not particularly limited. For example, the first retardation layer 10 has the puncture modulus E1 explained above. be able to. When obtaining the optical laminate 1b shown in FIG. 2, the puncture elastic modulus E1 of the first retardation layer 10 is preferably 15 g/mm or less, as explained above.

First, a process for preparing the optical laminate 1a shown in FIG. 1 will be described. In the method for manufacturing the optical laminate 1a, the step of preparing the laminate includes:
A step of preparing a first retardation layer with a base layer 18 having a first base layer 15 and a first retardation layer 10 ((a) in FIG. 5),
A step of preparing a second retardation layer with a base material layer 28 having the second base material layer 25 and the second retardation layer 20 described above ((b) of FIG. 5),
The first retardation layer 10 side of the first retardation layer 18 with a base material layer and the second retardation layer 20 side of the second retardation layer 28 with a base material layer are laminated via the lamination layer 32. process ((c) in Figure 5),
After the step of bonding via the bonding layer 32, a step of separating the first base layer 15 ((d) in FIG. 5),
It can include a step of bonding the exposed surface exposed by separating the first base layer 15 and the optical film 40 via the adhesive layer 31 ((e) in FIG. 5).

The first retardation layer 10 includes a first liquid crystal layer 12 formed by polymerizing a polymerizable liquid crystal compound on a first base layer 15 , and the second retardation layer 20 includes a first liquid crystal layer 12 formed by polymerizing a polymerizable liquid crystal compound on a first base layer 15 . It includes a second liquid crystal layer 22 (liquid crystal layer X) formed by polymerizing a polymerizable liquid crystal compound. Therefore, the step of preparing the first retardation layer 18 with a base material layer may include the step of polymerizing a polymerizable liquid crystal compound on the first base layer 15 to form the first liquid crystal layer 12. Further, the step of preparing the second retardation layer 28 with a base material layer may include the step of polymerizing a polymerizable liquid crystal compound on the second base layer 25 to form the second liquid crystal layer 22.

The first liquid crystal layer 12 may be formed by polymerizing a polymerizable liquid crystal compound on the first alignment layer 11 provided on the first base layer 15 . Similarly, the second liquid crystal layer 22 may be formed by polymerizing a polymerizable liquid crystal compound on the second alignment layer 21 provided on the second base layer 25. In this case, the step of preparing the first retardation layer 18 with a base material layer may include the step of forming the first alignment layer 11 on the first base layer 15. Further, the step of preparing the second retardation layer 28 with a base material layer may include the step of forming the second alignment layer 21 on the second base layer 25.

In the method for manufacturing the optical laminate 1a (FIG. 1), the step of bonding via the bonding layer 32 includes, for example, first the first retardation layer 10 side of the first retardation layer 18 with a base material layer, and/or Alternatively, a bonding agent composition layer for forming the bonding layer 32 is formed on the second retardation layer 20 side of the second retardation layer 28 with a base material layer. Next, a bonding layer 32 is formed from the bonding agent composition layer. The method for forming the bonding layer 32 from the bonding agent composition layer may be selected depending on the type of the bonding agent composition layer. For example, when the laminating agent composition is an adhesive composition, the laminating layer 32 as an adhesive cured layer is formed by curing the laminating agent by irradiation with active energy rays, heat treatment, etc. If the adhesive composition is a pressure-sensitive adhesive composition, the adhesive composition layer may be used as the adhesive layer 32, or the adhesive layer 32 may be formed from the adhesive composition layer. You can. As a result, as shown in FIG. A first laminate 61 can be obtained by stacking layers in this order.

In the first laminate 61, the first base layer 15 is preferably provided so as to be separable between the first base layer 15 and the first liquid crystal layer 12. Separable between the first base layer 15 and the first liquid crystal layer 12 means that the first base layer 15 is separable from the first liquid crystal layer 12, or that the first base layer 15 is separable from the first liquid crystal layer 12. If the first alignment layer 11 exists between the first alignment layer 12 and the first alignment layer 12, the first alignment layer 11 should be peelable from the first alignment layer 11, or the first alignment layer 11 should be peelable from the first liquid crystal layer 12. It means that it is removable. Therefore, when the first base layer 15 is removable from the first alignment layer 11, when the first base layer 15 is separated from the first laminate 61 as described later, the first liquid crystal The first alignment layer 11 remains on layer 12. If the first alignment layer 11 is removable from the first liquid crystal layer 12, when the first base layer 15 is separated from the first laminate 61, the first alignment layer 15 and the first base layer 15 are separated. Layer 11 is peeled off.

In the step of separating the first base layer 15, the first base layer 15 is separated from the first laminate 61 obtained in the step of bonding via the bonding layer 32. In the step of separating the first base layer 15, only the first base layer 15 may be peeled off, or if the first alignment layer 11 is present, the first alignment layer 11 is also removed together with the first base layer 15. It may be peeled off. As a result, the first retardation layer 10 (first alignment layer 11, first liquid crystal layer 12), bonding layer 32, second retardation layer 20 (second liquid crystal layer 22, second alignment layer 21), and A second laminate 62 is obtained in which the two base material layers 25 are laminated in this order (FIG. 5(d)).

In the step of bonding via the adhesive layer 31, for example, first, the exposed surface side exposed by separating the first base material layer 15 of the second laminate 62 shown in FIG. 5(d) and/or , an adhesive composition layer is formed on the optical film 40. Next, the second laminate 62 and the optical film 40 are laminated via the adhesive composition layer, and the adhesive composition layer is used as the adhesive layer 31, or the adhesive composition layer is used as the adhesive layer 31. form. As a result, the optical film 40, the adhesive layer 31, the first retardation layer 10 (the first alignment layer 11, the first liquid crystal layer 12), the bonding layer 32, the second retardation layer 20 (the second liquid crystal layer 22, An optical laminate 1c is obtained in which the second alignment layer 21) and the second base layer 25 are laminated in this order ((e) in FIG. 5, FIG. 3).

In the method for manufacturing the optical laminate 1a shown in FIG. 1, in the step of separating the second base layer 25, the second base layer 25 is separated from the optical laminate 1c. In the step of separating the second base material layer 25, only the second base material layer 25 may be peeled off, or if the second orientation layer 21 is present, the second orientation layer 21 is also removed together with the second base material layer 25. It may be peeled off. Thereby, the optical laminate 1a shown in FIG. 1 can be obtained.

Next, a process for preparing the above-mentioned laminate in the case of obtaining the optical laminate 1b shown in FIG. 2 will be explained. In the method for manufacturing the optical laminate 1b, the step of preparing the laminate includes:
A step of preparing a first retardation layer with a base layer 18 having a first base layer 15 and a first retardation layer 10 ((a) in FIG. 5),
A step of preparing a second retardation layer with a base material layer 28 having the second base material layer 25 and the second retardation layer 20 described above ((b) of FIG. 5),
A step of laminating the optical film 40 and the first retardation layer 10 side of the first retardation layer 18 with a base material layer via the adhesive layer 31 ((a) in FIG. 6),
After the step of bonding via the adhesive layer 31, a step of separating the first base layer 15 ((b) in FIG. 6),
A step of laminating the exposed surface exposed by separating the first base layer 15 and the second retardation layer 20 side of the second retardation layer 28 with a base layer via the lamination layer 32 (see FIG. 6(c)).

Examples of methods for obtaining the first retardation layer 18 with a base material layer and the second retardation layer 28 with a base material layer include the methods described above. Although FIG. 6 shows a case where the first retardation layer 18 is a laminate of the first alignment layer 11 and the first liquid crystal layer 12, the first retardation layer 18 does not include the first alignment layer 11. You don't have to be there. Similarly, FIG. 6 shows a case where the second retardation layer 28 is a laminate of the second alignment layer 21 and the second liquid crystal layer 22; It does not have to contain.

In the step of bonding via the adhesive layer 31, for example, first, an adhesive composition layer is applied to the first retardation layer 10 side of the first retardation layer 18 with a base material layer and/or the optical film 40. Form. Next, the first retardation layer 18 with a base material layer and the optical film 40 are laminated via the adhesive composition layer, and the adhesive composition layer is used as the adhesive layer 31, or the adhesive composition layer An adhesive layer 31 is formed from this. Thereby, a third laminate 63 in which the optical film 40, the adhesive layer 31, the first retardation layer 10 (the first alignment layer 11, the first liquid crystal layer 12), and the first base layer 15 are laminated in this order is obtained (FIG. 6(a)).

In the step of separating the first base layer 15, the first base layer 15 is separated from the laminate shown in FIG. 6(a). In the step of separating the first base layer 15, only the first base layer 15 may be separated, or if the first alignment layer 11 is present, the first alignment layer 11 is also included together with the first base layer 15. It may be peeled off. If the puncture elastic modulus E1 of the first retardation layer 10 is 15 g/mm or less, even when the first base layer 15 is separated, cracks may occur in the first retardation layer 10 or the first base material It is thought that this suppresses the occurrence of defects such as breakage of the layer 15, and facilitates good separation of the first base layer 15. As a result, a fourth laminate 64 is obtained in which the optical film 40, the adhesive layer 31, and the first retardation layer 10 (first liquid crystal layer 12, first alignment layer 11) are laminated in this order (see FIG. 6). (b)).

In the step of bonding via the bonding layer 32, for example, first, the exposed surface side of the fourth laminate 64 shown in FIG. 6(b) exposed by separating the first base layer 15, and/or Alternatively, a bonding agent composition layer for forming the bonding layer 32 is formed on the second retardation layer 20 side of the second retardation layer 28 with a base material layer. Next, after laminating the fourth laminate 64 and the second retardation layer 28 with a base material layer via the adhesive composition layer, the adhesive layer 32 is formed from the adhesive composition layer. Examples of the method for forming the bonding layer 32 from the bonding agent composition layer include the methods described above. As a result, the optical film 40, the adhesive layer 31, the first retardation layer 10 (first liquid crystal layer 12, first alignment layer 11), the bonding layer 32, the second retardation layer 20 (second liquid crystal layer 22, An optical laminate 1d is obtained in which the second alignment layer 21) and the second base layer 25 are laminated in this order ((c) in FIG. 6, FIG. 4).

In the method for manufacturing the optical laminate 1b shown in FIG. 2, in the step of separating the second base layer 25, the second base layer 25 is separated from the optical laminate 1d. In the step of separating the second base material layer 25, only the second base material layer 25 may be peeled off, or if the second orientation layer 21 is present, the second orientation layer 21 is also removed together with the second base material layer 25. It may be peeled off. Thereby, the optical laminate 1b shown in FIG. 2 can be obtained.

(Optical laminate of second embodiment)
7 and 8 are schematic cross-sectional views schematically showing an example of the optical laminate of this embodiment (second embodiment). As shown in FIGS. 7 and 8, the optical laminates 2a and 2b (hereinafter sometimes collectively referred to as "optical laminates 2") of the present embodiment include an optical film 40, an adhesive layer 31, and a retardation layer (X) 50 in this order. The retardation layer (X) 50 includes a liquid crystal layer (X) 52 that is a cured layer of a polymerizable liquid crystal compound. The puncture elastic modulus E(X) of the retardation layer (X) 50 is 15 g/mm or less.

As shown in FIG. 8, the optical laminate 2 may have a base layer (X) 55 on the side opposite to the adhesive layer 31 side of the retardation layer (X). The base material layer (X) 55 is preferably provided so as to be separable between the base material layer (X) 55 and the liquid crystal layer (X) 52 included in the retardation layer (X) 50.

Separable between the base material layer (X) 55 and the liquid crystal layer (X) 52 means that the base material layer (X) 55 is separable from the liquid crystal layer (X) 52, or the base material layer (X) 55 is separable from the liquid crystal layer (X) 52. When the alignment layer (X) 51 exists between the layer (X) 55 and the liquid crystal layer (X) 52, it must be peelable from the alignment layer (X) 51, or the alignment layer (X) 51 This means that it can be peeled off from the liquid crystal layer (X) 52. Therefore, when the base layer (X) 55 is removable from the alignment layer (X) 51, when the base layer (X) 55 is separated from the optical laminate 2b (FIG. 8), the liquid crystal The alignment layer (X) 51 remains on the layer (X) 52 (FIG. 7). When the alignment layer (X) 51 is peelable from the liquid crystal layer (X) 52, when the base material layer (X) 55 is separated from the optical laminate 2b, the base material layer (X) 55 and the The alignment layer (X) 51 is peeled off.

The retardation layer (X) may be the liquid crystal layer (X) 52 itself, which is a layer of a cured product of a polymerizable liquid crystal compound, or may be a laminate of the liquid crystal layer (X) 52 and the alignment layer (X) 51. You can. When the retardation layer (X) 50 has an alignment layer (X) 51, the alignment layer (X) 51 is provided on the side of the liquid crystal layer (X) 52 opposite to the adhesive layer 31 side.

The puncture elastic modulus E(X) of the retardation layer (X) 50 is 15 g/mm or less, may be 12 g/mm or less, may be 10 g/mm or less, and may be 9 g/mm or less. There may be. The puncture elastic modulus E(X) is usually 3 g/mm or more, may be 5 g/mm or more, or may be 7 g/mm or more. The puncture elastic modulus E(X) is a value at a temperature of 23° C. and a relative humidity of 50%, and can be measured according to the procedure of the method for measuring the puncture elastic modulus described in the Examples below. When the retardation layer (X) 50 is a laminate of a liquid crystal layer (X) 52 and an alignment layer (X) 51, the puncture elastic modulus E(X) of the retardation layer (X) 50 is the same as the alignment layer (X). X) Measure by piercing the needle from the 51 side. In the retardation layer (X) 50, no temperature dependence of the puncture elastic modulus E(X) is observed in the range of 23 to 80°C.

As a method for adjusting the puncture elastic modulus E(X) of the retardation layer (X) 50 and a preliminary experiment method for setting the puncture elastic modulus E(X) within a predetermined range, the first retardation layer described above is used. 10 and the piercing modulus of elasticity E1, E2 of the second retardation layer 20.

The thickness of the retardation layer (X) 50 is preferably 1.0 μm or more, more preferably 1.5 μm or more, may be 1.7 μm or more, or even 2.0 μm or more. good. The thickness of the retardation layer (X) 50 is usually 8 μm or less, may be 5 μm or less, may be 3.5 μm or less, or may be 3.0 μm or less.

It is considered that the smaller the puncture elastic modulus E(X) of the retardation layer (X) 50, the softer the retardation layer (X) 50 becomes. As described later, the optical laminate 2a can be obtained by separating the base layer (X) 55 from the optical laminate 2b. When the puncture elastic modulus E(X) of the retardation layer (X) 50 becomes smaller, the retardation layer (X) 50 will more easily follow the movement of peeling off the base layer (X) 55. It is considered that the base material layer (X) 55 is easily separated regardless of the separation speed of ) 55. On the other hand, it is thought that as the puncture elastic modulus E(X) increases, the retardation layer (X) 50 becomes harder, making it difficult for the retardation layer (X) 50 to follow the movement of peeling off the base layer (X) 55. It will be done. Therefore, depending on the separation speed of the base material layer (X) 55, cracks may occur in the retardation layer (X) 50 or the base material layer (X) 55 may break when the base material layer (X) 55 is separated. There is a possibility that such problems may occur.

In the optical laminate 2, since the puncture elastic modulus E(X) of the retardation layer (X) 50 is within the above-described range, the base material layer (X) 55 can be separated well. In particular, it is possible to suppress a large variation in the peeling force required to separate the base layer (X) 55 depending on the separation speed of the base layer (X) 55. On the other hand, if the puncture elastic modulus E(X) of the retardation layer (X) 50 is not within the above range, the peeling force will vary greatly depending on the separation speed of the base material layer (X) 55, and the separation speed Depending on the situation, the above-mentioned problems may occur.

The adhesive layer 31 is a layer for laminating the optical film 40 and the retardation layer (X), and is a layer formed using an adhesive composition. The adhesive layer 31 can be in direct contact with the optical film 40 and the retardation layer (X).

It is preferable that the adhesive layer 31 has the storage modulus at a temperature of 23° C. and a temperature of 80° C. as described above. It is thought that because the storage elastic modulus of the adhesive layer 31 at a temperature of 23° C. is within the above range, the adhesive layer 31 can easily follow the movement of peeling off the base layer (X) 55. Thereby, the base material layer (X) 55 can be easily separated from the optical laminate 2b regardless of the separation speed of the base material layer (X) 55. On the other hand, if the storage elastic modulus of the adhesive layer 31 at a temperature of 23° C. is not within the above range, the adhesive layer 31 will have difficulty following the movement of peeling off the base layer (X) 55, and ) 55, there is a risk that problems such as cracks occurring in the retardation layer (X) 50 or breakage of the base material layer (X) 55 may occur when the base material layer (X) 55 is separated. be. Moreover, since the storage elastic modulus of the adhesive layer 31 at a temperature of 80° C. is within the above range, the base material layer (X ) 55, the base material layer (X) 55 can be easily separated from the optical laminate 2b.

As the optical film 40, those described above can be used.

The optical laminate 2 may be a circularly polarizing plate. In this case, the optical film 40 includes a linearly polarizing layer, a polarizing plate, or a polarizing plate with a protection film, and the retardation layer (X) 50 is a 1/4 wavelength retardation layer or a 1/4 wavelength retardation layer with reverse wavelength dispersion. It is a retardation layer. The optical laminate 2 can be used by being attached to an image display element of a liquid crystal display device or an organic EL (electroluminescence) display device, for example.

(Method for manufacturing optical laminate of second embodiment)
The optical laminate 2a manufactured by the method for manufacturing the optical laminate 2 includes the optical film 40, the adhesive layer 31, and the retardation layer (X) 50 described above in this order. The retardation layer (X) 50 has the puncture elastic modulus E(X) described above. It is preferable that the adhesive layer 31 has the storage modulus at a temperature of 23° C. and a temperature of 80° C. as described above.

The method for manufacturing the optical laminate 2a is as follows:
A step of preparing a base layer-attached retardation layer (X) having a base layer (X) 55 and a retardation layer (X) 50;
The retardation layer (X) 50 includes a liquid crystal layer (X) 52 formed by polymerizing a polymerizable liquid crystal compound on a base layer (X) 55,
A step of preparing a laminate having an optical film 40, an adhesive layer 31, a retardation layer (X), and a base layer (X) 55 in this order (FIG. 8),
The step of separating the base layer (X) 55 from the laminate is included.

In the method for manufacturing the optical laminate 2, the retardation layer (X) 50 has a puncture modulus E(X) within the range described above. Therefore, even when the base material layer (X) 55 is separated, problems such as cracks occurring in the retardation layer (X) 50 or breakage of the base material layer (X) 55 are suppressed, It becomes easy to separate the base material layer (X) 55 well.

The retardation layer (X) includes a liquid crystal layer (X) 52 formed by polymerizing a polymerizable liquid crystal compound on a base layer (X) 55. Therefore, the step of preparing the retardation layer with a base material layer (X) may include the step of polymerizing a polymerizable liquid crystal compound on the base material layer (X) 55 to form the liquid crystal layer (X) 52. good. The liquid crystal layer (X) 52 may be formed by polymerizing a polymerizable liquid crystal compound on the alignment layer (X) 51 provided on the base layer (X) 55. In this case, the step of preparing the base material layer-attached retardation layer (X) may include the step of forming the alignment layer (X) 51 on the base material layer (X) 55.

The step of preparing the laminate may include a step of laminating the optical film 40 and the retardation layer (X) 50 side of the base layer-attached retardation layer (X) via the adhesive layer 31. can. In the step of bonding via the adhesive layer 31, for example, first, an adhesive composition layer is placed on the retardation layer (X) 50 side of the base layer-attached retardation layer (X) and/or on the optical film 40. form. Next, the retardation layer with a base material layer (X) and the optical film 40 are laminated via the adhesive composition layer, and the adhesive composition layer is used as the adhesive layer 31, or the adhesive composition layer An adhesive layer 31 is formed from this. As a result, an optical laminate 2b is obtained in which the optical film 40, the adhesive layer 31, and the retardation layer (X) 50 (orientation layer (X) 51, liquid crystal layer (X) 52) are laminated in this order (Fig. 8).

In the step of separating the base material layer (X) 55, the base material layer (X) 55 is separated from the optical laminate 2b. In the step of separating the base material layer (X) 55, only the base material layer (X) 55 may be peeled off, or if the orientation layer (X) 52 is present, the orientation layer is removed together with the base material layer (X) 55. (X) 52 may also be peeled off. Thereby, an optical laminate 2a shown in FIG. 7 can be obtained.

The method for manufacturing the optical laminate 2a further includes forming an adhesive layer other than the adhesive layer 31 and a release film in order from the exposed surface side exposed by the step of separating the base layer (X) 55. It may include a process. Other pressure-sensitive adhesive layers can be used, for example, for bonding to an image display element of a display device. The release film can cover and protect the surface of the other adhesive layer on the side opposite to the retardation layer (X) 50 side, and can be provided so as to be removable from the other adhesive layer.

Hereinafter, details of each member used in the optical laminate of this embodiment and its manufacturing method will be explained.

(First retardation layer, second retardation layer, retardation layer (X))
The first retardation layer, the second retardation layer, and the retardation layer (X) (hereinafter collectively referred to as "retardation layer") are layers having retardation characteristics, and each It includes a first liquid crystal layer, a second liquid crystal layer, and a liquid crystal layer (X) which are cured layers of a polymerizable liquid crystal compound. The first retardation layer may include a first alignment layer in addition to the first liquid crystal layer. Similarly, the second retardation layer may have a second alignment layer in addition to the second liquid crystal layer. Similarly, the retardation layer (X) may have an alignment layer (X) in addition to the liquid crystal layer (X).

(First liquid crystal layer, second liquid crystal layer, and liquid crystal layer (X))
The first liquid crystal layer, the second liquid crystal layer, and the liquid crystal layer (X) (hereinafter, these may be collectively referred to as "liquid crystal layer") are cured product layers of a polymerizable liquid crystal compound. As the polymerizable liquid crystal compound, a rod-shaped polymerizable liquid crystal compound and a disc-shaped polymerizable liquid crystal compound can be used, and either one of these may be used, or a mixture containing both of these may be used. When the rod-shaped polymerizable liquid crystal compound is aligned horizontally or vertically with respect to the base layer (first base layer, second base layer, or base layer (X)), the light of the polymerizable liquid crystal compound The axis coincides with the long axis direction of the polymerizable liquid crystal compound. When the disc-shaped polymerizable liquid crystal compound is oriented, the optical axis of the polymerizable liquid crystal compound is in a direction perpendicular to the disc surface of the polymerizable liquid crystal compound. As the rod-shaped polymerizable liquid crystal compound, for example, those described in Japanese Patent Publication No. 11-513019 (claim 1, etc.) can be suitably used. Disc-shaped polymerizable liquid crystal compounds include those described in JP-A-2007-108732 (paragraphs [0020] to [0067], etc.) and JP-A-2010-244038 (paragraphs [0013] to [0108], etc.). can be suitably used.

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 occurs by aligning the optical axis of the polymerizable liquid crystal compound horizontally with respect to the plane of the base material layer, and in this case, the optical axis direction and the slow axis It matches the direction. When the polymerizable liquid crystal compound is discoidal, 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 base material layer, and in this case, the optical axis and the slow axis is orthogonal to The alignment state of the polymerizable liquid crystal compound can be adjusted by the combination of the alignment layer and the polymerizable liquid crystal compound.

A polymerizable liquid crystal compound is a compound that has at least one polymerizable group and has liquid crystallinity. When two or more kinds of polymerizable liquid crystal compounds are used together, it is preferable that at least one kind has two or more polymerizable groups in the molecule. A polymerizable group means a group that participates in a polymerization reaction, and is preferably a photopolymerizable group. Here, the photopolymerizable group refers to a group that can participate in a polymerization reaction by active radicals, acids, etc. generated from a photopolymerization initiator, which will be described later. Examples of the polymerizable group include vinyl group, vinyloxy group, 1-chlorovinyl group, isopropenyl group, 4-vinylphenyl group, acryloyloxy group, methacryloyloxy group, oxiranyl group, oxetanyl group, styryl group, allyl group, etc. It will be done. Among these, acryloyloxy group, methacryloyloxy group, vinyloxy group, oxiranyl group and oxetanyl group are preferable, and acryloyloxy group is more preferable. The liquid crystallinity of the polymerizable liquid crystal compound may be a thermotropic liquid crystal or a lyotropic liquid crystal, and if the thermotropic liquid crystal is classified by the degree of order, it may be a nematic liquid crystal or a smectic liquid crystal.

The thickness of the liquid crystal layer is not particularly limited, but is preferably 0.5 μm or more, may be 1 μm or more, and is usually 8 μm or less, may be 5 μm or less, and is preferably 3 μm or less.

(First alignment layer, second alignment layer, alignment layer (X))
The first alignment layer, the second alignment layer, and the alignment layer (X) (hereinafter, these may be collectively referred to as "alignment layers") are formed by polymerization contained in the liquid crystal layer formed on these alignment layers. It has an alignment regulating force that aligns the liquid crystal compound in a desired direction. It is preferable to have a solvent resistance that prevents dissolution by coating with a composition for forming a liquid crystal layer, which will be described later, and a heat resistance against heat treatment for removing the solvent and orienting the polymerizable liquid crystal compound.

The alignment layer may be a vertical alignment layer in which the molecular axis of the polymerizable liquid crystal compound is aligned perpendicularly to the base layer, or a horizontal alignment layer in which the molecular axis of the polymerizable liquid crystal compound is aligned horizontally to the base layer. Alternatively, it may be an inclined alignment layer in which the molecular axis of the polymerizable liquid crystal compound is aligned at an angle with respect to the base layer.

Examples of the alignment layer include an alignment polymer layer formed of an alignment polymer, a photoalignment polymer layer formed of a photoalignment polymer, and a groove alignment layer having an uneven pattern or a plurality of grooves on the layer surface. I can do it. The first alignment layer, the second alignment layer, and the alignment layer (X) may be the same alignment layer or different alignment layers.

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

The photo-alignable polymer layer is formed by coating a base layer (first base layer, second base layer, or base layer (X)) with a polymer having a photoreactive group or a composition containing a monomer and a solvent. However, it can be formed by irradiating light such as ultraviolet light. Particularly in the case where an alignment regulating force is to be exerted in the horizontal direction, it can be formed by irradiating polarized light. In this case, the alignment regulating force in the photo-alignable polymer layer can be arbitrarily adjusted by adjusting the polarized light irradiation conditions for the photo-alignable polymer.

The groove alignment layer can be formed, for example, by exposing and developing the surface of a photosensitive polyimide film through an exposure mask having pattern-shaped slits to form a concavo-convex pattern, or by applying activation to a plate-shaped master having grooves on the surface. A method of forming an uncured layer of energy ray curable resin, transferring this layer to a base material layer (first base material layer or second base material layer) and curing it; It can be formed by forming an uncured layer of resin, pressing a roll-shaped master having irregularities on this layer, or the like to form irregularities, and then curing the layer.

The alignment layer preferably contains a resin in which a polymerizable compound is polymerized, from the viewpoint that when the alignment layer is peeled off and removed together with the base layer, the alignment layer can be easily peeled off and removed together with the base layer. The above polymerizable compound is a compound having a polymerizable group, and is usually a non-liquid crystal polymerizable non-liquid crystal compound that does not become a liquid crystal state. The polymerizable groups of the polymerizable compound react with each other and the polymerizable compound is polymerized to become a resin.

When the alignment layer is peeled off and removed together with the base layer, the alignment layer may contain a resin such as a cured product obtained by curing a known monofunctional or polyfunctional (meth)acrylate monomer in the presence of a polymerization initiator. preferable. Examples of (meth)acrylate monomers include 2-ethylhexyl acrylate, cyclohexyl acrylate, diethylene glycol mono-2-ethylhexyl ether acrylate, diethylene glycol monophenyl ether acrylate, tetraethylene glycol monophenyl ether acrylate, trimethylolpropane triacrylate, lauryl acrylate, lauryl methacrylate, isobornyl acrylate, isobornyl methacrylate, 2-phenoxyethyl acrylate, tetrahydrofurfuryl acrylate, 2-hydroxypropyl acrylate, benzyl acrylate, tetrahydrofurfuryl methacrylate, 2-hydroxyethyl methacrylate, benzyl methacrylate, cyclohexyl methacrylate, Examples include methacrylic acid, urethane acrylate, pentaerythritol triacrylate, trimethylolpropane triacrylate, ditrimethylolpropane tetraacrylate, pentaerythritol tetraacrylate, dipentaerythritol polyacrylate, dipentaerythritol hexaacrylate, and the like. Note that the resin may be one type of these or a mixture of two or more types. When such a resin is used as an alignment layer, after forming a liquid crystal layer, the retardation layer with a base material layer (base material layer Peeling and removing the alignment layer together with the base material layer when separating the base material layer from the first retardation layer with the base material layer, the second retardation layer with the base material layer, or the retardation layer with the base material layer (X)). I can do it. In this specification, "(meth)acrylic" means either acrylic or methacryl. "(Meta)" in (meth)acrylate and the like has the same meaning.

If the alignment layer is not peeled off together with the base material layer and remains on the liquid crystal layer side, the alignment layer may be a resin such as a cured product of a trifunctional or higher functional (meth)acrylate monomer, imide monomer, or vinyl ether monomer. It is more preferable to contain a cured product obtained by curing a trifunctional or more functional (meth)acrylate monomer.

When forming an alignment layer by curing the polymerizable compound in the composition for forming an alignment layer by UV irradiation, the intensity of the UV light irradiation is not particularly limited, but is preferably 10 to 1,000 mW/cm ² , more preferably 100 to 600 mW/cm ² . If the light irradiation intensity to the composition for forming an alignment layer coated on the base layer is less than 10 mW/cm ² , the reaction time will be too long, and if it exceeds 1,000 mW/cm ² , the light irradiation intensity will not be radiated from the light source. There is a risk that wrinkles may occur in the base material layer due to the heat generated, resulting in uneven retardation. The irradiation intensity is an intensity in a wavelength range effective for activating a polymerization initiator, preferably a photoradical polymerization initiator, more preferably an intensity in a wavelength range of 400 nm or less, and even more preferably an intensity in a wavelength range of 280 to 320 nm. This is the intensity in the wavelength region. When irradiated with such light irradiation intensity once or multiple times, the cumulative amount of light is 10 mJ/cm ² or more, preferably 100 to 1,000 mJ/cm ² , more preferably 400 to 1,000 mJ/cm ² , and Preferably, it is set to 600 to 1,000 mJ/cm ² , particularly preferably 600 to 1,000 mJ/cm ² . If the cumulative amount of light applied to the composition for forming an alignment layer applied on the base layer is less than 10 mJ/ ^cm2 , the generation of active species derived from the polymerization initiator will not be sufficient, and the composition for forming an alignment layer will not be cured. becomes insufficient. Furthermore, when the cumulative light amount exceeds 1,000 mJ/cm ² , the irradiation time becomes extremely long, which is disadvantageous for improving productivity. The wavelength at the time of light irradiation (UVA (320-390 nm), UVB (280 to 320 nm, etc.) is different, and the required cumulative amount of light also changes depending on the wavelength at the time of light irradiation.

When curing the polymerizable compound in the composition for forming an alignment layer by ultraviolet irradiation, the temperature during ultraviolet irradiation is preferably 25°C or higher, more preferably 50°C or higher, from the viewpoint of sufficiently increasing the degree of polymerization. The temperature is more preferably 80°C or higher. In addition, if the temperature is too high, there is a concern that wrinkles will occur in the base layer and uneven retardation will occur, so the temperature during ultraviolet irradiation is preferably 200°C or lower, more preferably 150°C or lower, and Preferably it is 120°C or lower. In addition, the upper limit value and lower limit value mentioned above can be combined arbitrarily.

The thickness of the alignment layer is not particularly limited, but is preferably 0.01 μm or more, may be 0.05 μm or more, may be 0.1 μm or more, and is usually 5 μm or less, and 2.5 μm or less. The thickness may be 1 μm or less.

(First retardation layer with base layer, second retardation layer with base layer, retardation layer with base layer (X))
A first retardation layer with a base material layer, a second retardation layer with a base material layer, and a retardation layer with a base material layer (X) (hereinafter, these may be collectively referred to as "retardation layer with a base material layer") ) is a method of coating a liquid crystal layer forming composition containing a polymerizable liquid crystal compound on a base material layer, drying it, and forming a liquid crystal layer which is a cured layer formed by polymerizing the polymerizable liquid crystal compound. You can get it by doing When the alignment layer is formed on the base material layer, the composition for forming the liquid crystal layer may be applied on the alignment layer, and when the liquid crystal layer has a multilayer structure of two or more layers, the composition for forming the liquid crystal layer may be coated on the alignment layer. A multilayer structure may be formed by sequentially applying the composition. The method described above can be used to form the alignment layer.

The composition for forming a liquid crystal layer usually contains a solvent in addition to the polymerizable liquid crystal compound. The composition for forming a liquid crystal layer may further contain a polymerization initiator, a reactive additive, a polymerization inhibitor, and the like. These components may be used alone or in combination of two or more.

The solvent that may be contained in the composition containing the polymerizable liquid crystal compound is preferably a solvent that can dissolve the polymerizable liquid crystal compound and is inert to the polymerization reaction of the polymerizable liquid crystal compound. .

Examples of solvents include alcohol solvents such as methanol, ethanol, ethylene glycol, isopropyl alcohol, propylene glycol, methyl cellosolve, butyl cellosolve, propylene glycol monomethyl ether, and phenol; ester solvents such as ethyl acetate and butyl acetate; acetone, methyl ethyl ketone, and cyclopentanone. , cyclohexanone, cycloheptanone, methyl amyl ketone, methyl isobutyl ketone, N-methyl-2-pyrrolidinone, and other ketone solvents; pentane, hexane, heptane, and other non-chlorinated aliphatic hydrocarbon solvents; toluene, xylene, and other non-chlorinated solvents Examples include aromatic hydrocarbon solvents; nitrile solvents such as acetonitrile; ether solvents such as propylene glycol monomethyl ether, tetrahydrofuran, and dimethoxyethane; chlorinated hydrocarbon solvents such as chloroform and chlorobenzene; and the like. The solvents may be used alone or in combination.

The content of the solvent in the polymerizable liquid crystal composition is usually preferably 10 parts by mass to 10,000 parts by mass, more preferably 50 parts by mass to 5,000 parts by mass, based on 100 parts by mass of solid content. Note that the solid content means the total of components other than the solvent in the polymerizable liquid crystal composition.

The polymerization initiator that may be contained in the composition containing the polymerizable liquid crystal compound is a compound that can initiate the polymerization reaction of the polymerizable liquid crystal compound, and is a compound that can initiate the polymerization reaction under lower temperature conditions. Polymerization initiators are preferred. Specifically, photopolymerization initiators that can generate active radicals or acids by the action of light can be mentioned, and among them, photopolymerization initiators that can generate radicals by the action of light are preferred. Examples of the photoradical polymerization initiator include benzoin compounds, benzophenone compounds, benzyl ketal compounds, α-hydroxyketone compounds, α-aminoketone compounds, oxime compounds, triazine compounds, iodonium salts, and sulfonium salts. As the photoradical polymerization initiator, only one type may be used, or two or more types may be used in combination.

A commercially available product may be used as the photoradical polymerization initiator. Specifically, such commercial products include Irgacure (registered trademark) 907, Irgacure 184, Irgacure 651, Irgacure 819, Irgacure 250, Irgacure 369, Irgacure 379, Irgacure 127, Irgacure 2959, Irgacure 754, and Irgacure 379EG. (manufactured by BASF Japan Co., Ltd.), Sequal BZ, Seiqual Z, Seiqual BEE (manufactured by Seiko Chemical Co., Ltd.), Kayacure BP100 (manufactured by Nippon Kayaku Co., Ltd.), Kayacure UVI-6992 (manufactured by Dow Corporation) ), ADEKA OPTOMER SP-152, ADEKA OPTOMER SP-170, ADEKA OPTOMER N-1717, ADEKA OPTOMER N-1919, ADEKA ARCLES NCI-831, ADEKA ARCLES NCI-930 (all manufactured by ADEKA Co., Ltd.) ), TAZ-A, TAZ-PP (manufactured by Nippon Siberhegner Co., Ltd.), and TAZ-104 (manufactured by Sanwa Chemical Co., Ltd.).

The content of the polymerization initiator is usually 0.1 to 30 parts by weight, preferably 1 to 20 parts by weight, and more preferably 1 to 15 parts by weight, based on 100 parts by weight of the total amount of the polymerizable liquid crystal compound. Department. Within this range, the reaction of the polymerizable groups will proceed sufficiently, and the alignment state of the polymerizable liquid crystal compound will be easily stabilized.

A crosslinking agent that may be contained in a composition containing a polymerizable liquid crystal compound is a compound having one or more photo- or heat-reactive groups in the molecule. By using a crosslinking agent, the crosslinking density of the liquid crystal layer changes, making it easier to adjust the film strength. Examples of the crosslinking agent include polyfunctional acrylate compounds, epoxy compounds, oxetane compounds, methylol compounds, and isocyanate compounds. Among these, polyfunctional acrylate compounds are preferred from the viewpoint of uniformity of the coating film and adjustment of film strength. The crosslinking agent preferably has 2 to 8 reactive groups in the molecule, more preferably 2 to 6 polymerizable groups.

Commercially available products may be used as the polyfunctional acrylate. Specifically, such commercial products include A-DOD-N, A-HD-N, A-NOD-N, APG-100, APG-200, APG-400, A-GLY-9E, A- GLY-20E, A-TMM-3, A-TMPT, AD-TMP, ATM-35E, A-TMMT, A-9550, A-DPH, HD-N, NOD-N, NPG, TMPT (Shin Nakamura Chemical Co., Ltd. company), "ARONIX M-220", "ARONIX M-325", "M-240", "ARONIX M-270", "M-309", "M-310", "M-321" , "M-350", "M-360", "M-305", "M-306", "M-450", "M-451", "M-408", "M-400", "M-402", "M-403", "M-404", "M-405", "M-406" (manufactured by Toagosei Co., Ltd.), EBECRYL11", "145", "150", "40", "140", "180", DPGDA, HDDA, TPGDA, HPNDA, PETIA, PETRA, TMPTA, TMPEOTA, DPHA, EBECRYL series (Daicel・Manufactured by Cytec Co., Ltd.) etc.

The content of the crosslinking agent is preferably 1 part by mass to 30 parts by mass, more preferably 3 parts by mass to 20 parts by mass, based on 100 parts by mass of the total amount of the polymerizable liquid crystal compound. When the content of the crosslinking agent is below the lower limit, problems are likely to occur during processing such as polishing, and when it is above the upper limit, the alignment state of the liquid crystal compound becomes unstable and alignment defects are likely to occur.

The reactive additive that may be contained in the composition containing the polymerizable liquid crystal compound is preferably one having a carbon-carbon unsaturated bond and an active hydrogen-reactive group in its molecule. The term "active hydrogen-reactive group" as used herein refers to a group that is reactive with groups having active hydrogen, such as carboxyl group (-COOH), hydroxyl group (-OH), and amino group (-NH ₂ ). Representative examples thereof include a glycidyl group, an oxazoline group, a carbodiimide group, an aziridine group, an imide group, an isocyanate group, a thioisocyanate group, and a maleic anhydride group. The number of carbon-carbon unsaturated bonds and active hydrogen-reactive groups that the reactive additive has in its molecule is usually 1 to 20 each, preferably 1 to 10 each.

In the reactive additive, it is preferable that at least two active hydrogen-reactive groups exist in the molecule. In this case, the plurality of active hydrogen-reactive groups may be the same or different.

The carbon-carbon unsaturated bond that the reactive additive has in its molecule refers to a carbon-carbon double bond or a carbon-carbon triple bond, and preferably a carbon-carbon double bond. Among these, the reactive additive preferably contains a carbon-carbon unsaturated bond in the molecule as a vinyl group and/or (meth)acrylic group. Furthermore, it is preferable that the active hydrogen-reactive group is at least one selected from the group consisting of an epoxy group, a glycidyl group, and an isocyanate group. Particularly preferred are reactive additives having an acrylic group as a carbon-carbon double bond and an isocyanate group as an active hydrogen-reactive group.

Examples of reactive additives include compounds having a (meth)acrylic group and an epoxy group, such as methacryloxyglycidyl ether and acryloxyglycidyl ether; compounds having a (meth)acrylic group and an oxetane group, such as oxetane acrylate and oxetane methacrylate. Compounds having a (meth)acrylic group and a lactone group, such as lactone acrylate and lactone methacrylate; Compounds having a vinyl group and an oxazoline group, such as vinyloxazoline and isopropenyloxazoline; Isocyanatomethyl acrylate, isocyanato Examples include compounds having a (meth)acrylic group and an isocyanate group, such as methyl methacrylate, 2-isocyanatoethyl acrylate, and 2-isocyanatoethyl methacrylate, and oligomers of these monomers. Other examples include compounds having a vinyl group or vinylene group and an acid anhydride, such as methacrylic anhydride, acrylic anhydride, maleic anhydride, and vinyl maleic anhydride. Among these, methacryloxyglycidyl ether, acryloxyglycidyl ether, isocyanatomethyl acrylate, isocyanatomethyl methacrylate, vinyloxazoline, 2-isocyanatoethyl acrylate, 2-isocyanatoethyl methacrylate, or oligomers of these monomers are preferred, and isocyanatomethyl Particularly preferred are acrylate, 2-isocyanatoethyl acrylate, or oligomers of these monomers.

When the polymerizable liquid crystal composition contains a reactive additive, the content is usually 0.1 parts by mass or more and 30 parts by mass or less, preferably 0.1 parts by mass, based on 100 parts by mass of the polymerizable liquid crystal compound. It is not less than 5 parts by mass and not more than 5 parts by mass.

The composition containing the polymerizable liquid crystal compound may contain a leveling agent in order to make the coating film obtained by applying the composition more flat. Examples of the leveling agent include silicone-based, polyacrylate-based, and perfluoroalkyl-based leveling agents.

The content of the leveling agent is preferably 0.01 to 5 parts by weight, more preferably 0.05 to 3 parts by weight, based on 100 parts by weight of the polymerizable liquid crystal compound. When the content of the leveling agent is within the above range, it is easy to orient the polymerizable liquid crystal compound, and the resulting cured liquid crystal film (cured layer of the polymerizable liquid crystal compound) tends to be smoother. It is preferable because it is.

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

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

Photopolymerization can be carried out by irradiating the polymerizable liquid crystal compound in the dry film with active energy rays. The active energy ray to be irradiated can be selected as appropriate depending on the type and amount of polymerizable groups possessed by the polymerizable liquid crystal compound, the type of photopolymerization initiator, etc., but examples include visible light, ultraviolet rays, and laser light. , X-rays, α-rays, β-rays, and γ-rays. Among these, ultraviolet light is preferable because it is easy to control the progress of the polymerization reaction and it is possible to use photopolymerization equipment that is widely used in this field. It is preferable to select the type of photopolymerization initiator. During photopolymerization, the polymerization temperature can also be controlled by irradiating active energy rays while cooling the dried film using an appropriate cooling means.

When curing the coating layer of the composition for forming a liquid crystal layer by ultraviolet irradiation, the intensity of ultraviolet light irradiation is not particularly limited, but is preferably 10 to 1,000 mW/cm ² , and preferably 100 to 600 mW/cm ² . It is more preferable that there be. If the light irradiation intensity to the coating layer is less than 10 mW/ ^cm2 , the reaction time will be too long, and if it exceeds 1,000 mW/ ^cm2 , wrinkles will occur in the base material layer due to the heat radiated from the light source. This may cause phase difference unevenness. The irradiation intensity is an intensity in a wavelength range effective for activating a polymerization initiator, preferably a photoradical polymerization initiator, more preferably an intensity in a wavelength range of 400 nm or less, and even more preferably an intensity in a wavelength range of 280 to 320 nm. This is the intensity in the wavelength region. When irradiated with such light irradiation intensity once or multiple times, the cumulative amount of light is 10 mJ/cm ² or more, preferably 100 to 1,000 mJ/cm ² , more preferably 400 to 1,000 mJ/cm ² , and Preferably, it is set to 600 to 1000 mJ/cm ² , particularly preferably 600 to 1,000 mJ/cm ² . If the cumulative amount of light applied to the coating layer is less than 10 mJ/cm ² , active species derived from the polymerization initiator will not be sufficiently generated, resulting in insufficient curing of the coating layer. Furthermore, when the cumulative light amount exceeds 1,000 mJ/cm ² , the irradiation time becomes extremely long, which is disadvantageous for improving productivity. The wavelength at the time of light irradiation (UVA (320 to 390 nm), UVB (280 to 320 nm, etc.) is different, and the required cumulative amount of light also changes depending on the wavelength at the time of light irradiation.

When curing the coating layer of the composition for forming a liquid crystal layer by ultraviolet irradiation, the temperature at the time of ultraviolet irradiation is preferably 25°C or higher, more preferably 50°C or higher, from the viewpoint of sufficiently increasing the degree of polymerization. More preferably, the temperature is 80°C or higher. In addition, if the temperature is too high, there is a concern that wrinkles will occur in the base material layer and uneven retardation will occur. The temperature is 120°C or less. In addition, the upper limit value and lower limit value mentioned above can be combined arbitrarily.

(First base layer, second base layer, base layer (X))
The first base material layer, the second base material layer, and the base material layer (X) (hereinafter, these may be collectively referred to as "base material layers") are formed on these base material layers as described below. It has a function as a supporting layer that supports an alignment layer and a 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, etc. is used. Specifically, polyolefin resins such as polyethylene and polypropylene; cyclic polyolefin resins such as norbornene polymers; polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate; (meth)acrylic acid and poly(meth)acrylic (meth)acrylic acid-based resins such as methyl acid; cellulose ester-based resins such as triacetylcellulose, diacetylcellulose, and cellulose acetate propionate; vinyl alcohol-based resins such as polyvinyl alcohol and polyvinyl acetate; polycarbonate-based resins; polystyrene-based resins Resin; polyarylate resin; polysulfone resin; polyether sulfone resin; polyamide resin; polyimide resin; polyether ketone resin; polyphenylene sulfide resin; polyphenylene oxide resin, and mixtures and copolymers thereof, etc. can be mentioned. Among these resins, it is preferable to use any one of a cyclic polyolefin resin, a polyester resin, a cellulose ester resin, and a (meth)acrylic acid resin, or a mixture thereof.

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

When the first retardation layer with a base material layer has a first orientation layer, or when the second retardation layer with a base material layer has a second orientation layer, the adhesion between the first base material layer and the first orientation layer In order to improve the adhesiveness between the second base material layer and the second alignment layer, at least the surface of the first base material layer on the side where the first alignment layer is formed, and at least the second base material Corona treatment, plasma treatment, flame treatment, etc. may be performed on the surface of the layer on which the second orientation layer is formed, and a primer layer or the like may be formed.

The base material layer is peelable from the liquid crystal layer or the alignment layer, and the magnitude of the peeling force between the base material layer and the liquid crystal layer or the alignment layer is determined by considering the order in which the base material layers are separated. Need to decide. It is preferable that the peeling force of the first base layer that is separated first from the first laminate is smaller than the peeling force of the second base layer that is separated later.

(Adhesive layer, other adhesive layer)
The adhesive layer and other adhesive layers (hereinafter, both may be simply referred to as "adhesive layers") refer to layers composed of an adhesive composition. In this specification, the term "adhesive" refers to an adhesive that exhibits adhesive properties by pasting itself onto an adherend such as a polarizing plate or a liquid crystal layer, and is a so-called pressure-sensitive adhesive. . Furthermore, the degree of crosslinking and adhesive strength of the active energy ray-curable adhesive described below can be adjusted by irradiating it with energy rays.

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

The adhesive layer may be formed using an active energy ray-curable adhesive. Active energy ray-curable adhesives are made by blending an ultraviolet-curable compound such as a polyfunctional acrylate into an adhesive composition, forming an adhesive layer, and then curing it by irradiating it with ultraviolet rays to create a harder adhesive. layers can be formed. Active energy ray-curable adhesives have the property of being cured by irradiation with energy rays such as ultraviolet rays and electron beams. Activated energy ray-curable adhesives have adhesive properties even before irradiation with energy rays, so they adhere closely to adherends such as optical films and retardation layers, and harden upon irradiation with energy rays to increase adhesion. It is an adhesive with properties that can be adjusted.

Active energy ray-curable adhesives generally contain an acrylic adhesive and an energy ray polymerizable compound as main components. Usually, a crosslinking agent is further blended, and if necessary, a photopolymerization initiator, a photosensitizer, etc. can also be blended.

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

(Lamination layer)
The lamination layer can be an adhesive layer or an adhesive cured layer. Examples of the adhesive layer include those described above. The adhesive cured layer can be formed using an adhesive composition.

The adhesive cured layer refers to an adhesive cured layer formed by curing the curable component in the adhesive composition. Examples of the adhesive composition for forming the adhesive cured layer include adhesives other than pressure-sensitive adhesives (adhesives), such as water-based adhesives and active energy ray-curable adhesives. Examples of water-based adhesives include adhesives in which polyvinyl alcohol-based resin is dissolved or dispersed in water. Examples of active energy ray-curable adhesives include solvent-free active energy ray-curable adhesives containing a curable compound that is cured by irradiation with active energy rays such as ultraviolet rays, visible light, electron beams, and X-rays. Can be mentioned. By using a solvent-free active energy ray-curable adhesive, interlayer adhesion can be improved. On the other hand, if the active energy ray-curable adhesive contains a solvent (especially an organic solvent), sufficient adhesion may not be obtained even if the curable components contained in the adhesive are the same. Therefore, when the optical laminate is cut into a predetermined size, problems such as peeling at the ends are likely to occur. Furthermore, since a step of drying the solvent is added, additional shrinkage stress due to heat is applied, and there is a possibility that the optical laminate is likely to curl.

The active energy ray-curable adhesive preferably contains one or both of a cationically polymerizable curable compound and a radically polymerizable curable compound, since it exhibits good adhesive properties. The active energy ray-curable adhesive may further include 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 (compounds having one or more oxetane rings in the molecule). or a combination thereof.

Examples of radically polymerizable curable compounds include (meth)acrylic compounds (compounds having one or more (meth)acryloyloxy groups in the molecule), and others having radically polymerizable double bonds. or a combination thereof.

The active energy ray-curable adhesive can contain a sensitizer, if necessary. By using a sensitizer, the reactivity is improved and the mechanical strength and adhesive strength of the cured adhesive layer can be further improved. As the sensitizer, any known sensitizer can be used as appropriate. When a sensitizer is blended, the blending amount is preferably in the range of 0.1 to 20 parts by mass based on 100 parts by mass of the total amount of the active energy ray-curable adhesive.

Active energy ray curable adhesives contain ion trapping agents, antioxidants, chain transfer agents, tackifiers, thermoplastic resins, fillers, flow regulators, plasticizers, antifoaming agents, and antistatic agents, as required. It may contain additives such as a chemical agent, a leveling agent, and a solvent.

The adhesive composition layer may be formed by applying the adhesive composition to the bonding surface of the first retardation layer with a base material layer or the second retardation layer with a base material layer. As a coating method, a conventional coating technique using a die coater, comma coater, reverse roll coater, gravure coater, rod coater, wire bar coater, doctor blade coater, air doctor coater, etc. may be employed.

The drying method when using a water-based adhesive is not particularly limited, but for example, a method of drying using a hot air dryer or an infrared dryer can be adopted.

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

The thickness of the adhesive cured layer is, for example, 0.01 μm or more, may be 0.05 μm or more, may be 0.5 μm or more, and is usually 5 μm or less, and may be 3 μm or less, It may be 2 μm or less.

(linear polarizing layer)
The linearly polarizing layer has a property of transmitting linearly polarized light having a vibration plane perpendicular to the absorption axis when unpolarized light is incident thereon. The linearly polarizing layer may include a polyvinyl alcohol (hereinafter sometimes abbreviated as "PVA") based resin film, in which a dichroic dye is aligned to a polymerizable liquid crystal compound, and a dichroic dye is oriented to the polymerizable liquid crystal compound. It may also be a cured film obtained by polymerization.

The linearly polarizing layer containing a PVA resin film is, for example, a hydrophilic polymer film such as a PVA film, a partially formalized PVA film, or a partially saponified ethylene/vinyl acetate copolymer film. Examples include those that have been dyed with a dichroic substance such as a dye, and those that have been subjected to a stretching process. Since it has excellent optical properties, it is preferable to use a linearly polarizing layer obtained by dyeing a PVA resin film with iodine and uniaxially stretching it.

PVA-based resin can be produced by saponifying polyvinyl acetate-based resin. In addition to polyvinyl acetate, which is a homopolymer of vinyl acetate, the polyvinyl acetate resin can also be a copolymer of vinyl acetate and another monomer copolymerizable with vinyl acetate. Other monomers copolymerizable with vinyl acetate include, for example, unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, acrylamides having an ammonium group, and the like.

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

A film formed from such a PVA-based resin is used as an original film for the linearly polarizing layer. The method of forming a PVA resin into a film is not particularly limited, and any known method can be used to form the film. The thickness of the PVA resin raw film is, for example, about 10 to 100 μm, preferably about 10 to 60 μm, and more preferably about 15 to 30 μm.

Another method for producing a linear polarizing layer containing a PVA-based resin film is to first prepare a base film, apply a solution of a resin such as PVA-based resin onto the base film, and dry it to remove the solvent. Examples include those including a step of forming a resin layer on a base film. Note that a primer layer can be formed in advance on the surface of the base film on which the resin layer is to be formed. As the base film, a resin film such as PET can be used. Examples of the material for the primer layer include PVA resin, which is a crosslinked hydrophilic resin used in the linearly polarizing layer.

Next, the amount of solvent such as moisture in the resin layer is adjusted as necessary, and then the base film and the PVA resin layer are uniaxially stretched, and then the PVA resin layer is dyed with a dichroic dye such as iodine. The dichroic dye is adsorbed and aligned on the PVA resin layer. Subsequently, if necessary, the PVA resin layer on which the dichroic dye has been adsorbed and oriented is treated with an aqueous boric acid solution, and a cleaning step is performed in which the aqueous boric acid solution is washed away. As a result, a PVA resin layer in which the dichroic dye is adsorbed and oriented, that is, a film of a linearly polarizing layer is manufactured. A known method can be adopted for each step.

The uniaxial stretching of the base film and the PVA resin layer may be carried out before dyeing, during dyeing, or during boric acid treatment after dyeing. Uniaxial stretching may also be performed. The base film and the PVA 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 circumferential speeds, or uniaxially stretched using hot rolls. It may be stretched. Further, the base film and the PVA resin layer may be uniaxially stretched in the TD direction (direction perpendicular to the film transport direction), and in this case, a so-called tenter method can be used. Further, the stretching of the base film and the PVA resin layer may be performed by dry stretching in the atmosphere, or by wet stretching in which the PVA resin layer is swollen with a solvent. . In order to exhibit the performance of the linearly polarizing layer, the stretching 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 to the stretching ratio, it is preferably 8 times or less from the viewpoint of suppressing breakage and the like.

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

As a method for producing a linearly polarizing layer, which is a cured film in which a dichroic dye is aligned on a polymerizable liquid crystal compound and the polymerizable liquid crystal compound is polymerized, the polymerizable liquid crystal compound and the dichroic dye are placed on a base film. A method may be mentioned in which a polarizing layer forming composition containing the polarizing layer forming composition is applied, and a polymerizable liquid crystal compound is polymerized and cured while maintaining the liquid crystal state to form a linearly polarizing layer. The linearly polarizing layer thus obtained is in a state of being laminated on a base film, and the linearly polarizing layer with a base film may be used as a polarizing plate, which will be described later.

As the dichroic dye, a dye can be used 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 a maximum absorption 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, and anthraquinone dyes, among which azo dyes are preferred. Examples of the azo dye include monoazo dyes, bisazo dyes, trisazo dyes, tetrakisazo dyes, and stilbene azo dyes, with bisazo dyes and trisazo dyes being more preferred.

The composition for forming a polarizing layer may contain a solvent, a polymerization initiator such as a photopolymerization initiator, a photosensitizer, a polymerization inhibitor, and the like. Regarding the polymerizable liquid crystal compound, dichroic dye, solvent, polymerization initiator, photosensitizer, polymerization inhibitor, etc. contained in the composition for forming a polarizing layer, known ones can be used. Those illustrated in JP-A No. 2017-102479 and JP-A No. 2017-83843 can be used. Further, the polymerizable liquid crystal compound may be the same as the compound exemplified as the polymerizable liquid crystal compound used to obtain the liquid crystal layer (first liquid crystal layer, second liquid crystal layer) described later. As for the method of forming a linearly polarizing layer using the composition for forming a polarizing layer, the method exemplified in the above-mentioned publication can be adopted.

The thickness of the linearly polarizing layer is preferably 2 μm or more, more preferably 3 μm or more. Further, the thickness of the linearly polarizing layer 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 lower limit value mentioned above can be combined arbitrarily.

(Polarizer)
A polarizing plate can be obtained by laminating a protective layer on one or both surfaces of the linearly polarizing layer via a known pressure-sensitive adhesive layer or a cured adhesive layer. This polarizing plate is a so-called linear polarizing plate. The protective layer that can be laminated on one or both sides of the linearly polarizing layer is made of, for example, a thermoplastic resin that has 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 triacetylcellulose; polyester resins such as PET and polyethylene naphthalate; polyethersulfone resins; polysulfone resins; polycarbonate resins; polyamide resins such as nylon and aromatic polyamides. ; Polyimide resin; Polyolefin resins such as polyethylene, polypropylene, and ethylene/propylene copolymers; Cyclic polyolefin resins having cyclo and norbornene structures (also referred to as norbornene resins); (meth)acrylic resins; Polyarylate resins; Polystyrene resins; Mention may be made of polyvinyl alcohol resins as well as mixtures thereof. When protective layers are laminated on both sides of the linearly polarizing layer, the resin compositions of the two protective layers may be the same or different.

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

The protective layer may be, for example, a stretched thermoplastic resin or an unstretched thermoplastic resin (hereinafter sometimes referred to as "unstretched resin"). Examples of the stretching treatment include uniaxial stretching and biaxial stretching.

The thickness of the protective layer is preferably 3 μm or more, more preferably 5 μm or more. Further, 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 lower limit value mentioned above can be combined arbitrarily.

The surface of the protective layer opposite to the linearly polarizing layer may have a surface treatment layer, such as a hard coat layer, an antireflection layer, an antisticking layer, an antiglare layer, a diffusion layer, etc. good. The surface treatment layer may be another layer laminated on the protective layer, or may be formed by subjecting the surface of the protective layer to surface treatment.

The thickness of the polarizing plate is not particularly limited, but is usually 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 usually be made into a polarizing plate with a protection film by laminating a protection film on one side thereof. The protect film may be formed by forming an adhesive layer on a resin film for protection film, or may be formed from a self-adhesive film. The thickness of the protect film can be, for example, 30 to 200 μm, preferably 40 to 150 μm, and more preferably 50 to 120 μm.

Examples of resins constituting the resin film for the protect film include polyolefin resins such as polyethylene resins and polypropylene resins; cyclic polyolefin resins; polyester resins such as PET and polyethylene naphthalate; polycarbonate resins; Examples include meth)acrylic resins. Among these, polyester resins such as PET are preferred. The resin film for the protect film may have a single layer structure, or may have a multilayer structure of two or more layers.

A self-adhesive film is a film that can adhere to itself without providing a means for adhesion such as an adhesive layer, and can maintain the adhered state. The self-adhesive film can be formed using, for example, polypropylene resin, polyethylene resin, or the like.

The thickness of the polarizing plate with a protection film is preferably 32 μm or more and 500 μm or less. The thickness of the polarizing plate with a protection film may be 40 μm or more, 350 μm or less, 200 μm or less, or 150 μm or less.

(Release film)
The release film covers and protects the other adhesive layer or supports the other adhesive layer, and has a function as a separator that can be peeled off from the other adhesive layer. Examples of the release film include a film in which the surface of the base film on the pressure-sensitive adhesive layer side has been subjected to release treatment such as silicone treatment. Examples of the resin material forming the base film include the same resin materials as those forming the protective layer described above. The resin film may have a single layer structure, or may be a multilayer resin film having a multilayer structure of two or more layers.

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

[Measurement of piercing elastic modulus]
(Preparation of measurement sample)
The retardation layer with a base material layer (first retardation layer with a base material layer, second retardation layer with a base material layer, or retardation layer with a base material layer (X)) used in Examples and Comparative Examples was 40 mm. It was cut out to a size of 40 mm, and this was used as a cut piece. In addition, a 40 mm x 40 mm adhesive mount was prepared. This glued mount has a 30 mm x 30 mm square cut out in the center. Laminate the cut-out piece on the adhesive mount so that the surface of the retardation layer (first retardation layer, second retardation layer, or retardation layer (X)) of the cut-out piece is in contact with the glue on the adhesive mount did. Subsequently, the base material layer (the first base material layer, the second base material layer, or the base material layer (X)) was separated from the cut piece to prepare a measurement sample for the puncture elastic modulus E2.

(Determination of piercing elastic modulus)
A needle with a tip diameter of 1 mmφ and 0.5 R was attached to a handy compression testing machine (“NDG5 Puncture Testing Machine Needle Penetration Force Measurement Specification”, manufactured by Kato Tech Co., Ltd.). A needle was pierced perpendicularly to the retardation layer surface of the measurement sample from the retardation layer side of the measurement sample (the side opposite to the glued mount side) at a stabbing speed of 0.33 cm/sec. The amount of strain S [mm] at stress F [g] immediately before the measurement sample breaks due to this piercing was calculated, and the value of stress F [g]/amount of strain S [mm] was calculated. This operation was performed for each of the five measurement samples, and the average value was determined as the piercing elastic modulus [g/mm]. The measurements were performed in an environment with a temperature of 23° C. and a relative humidity of 50%.

[Measurement of storage modulus of adhesive layer]
The storage modulus of the adhesive layer was determined by using a cylindrical piece with a diameter of 8 mm and a thickness of 1 mm as a test piece, using a viscoelasticity measuring device "DYNAMIC ANARYZER RDA II" manufactured by REOMETRIC, and using a torsional shear method at a frequency of 1 Hz. Measurements were made at a temperature of 23°C and a temperature of 80°C.

[Evaluation of peelability]
(Peeling test of second base layer)
The adhesive used in the production of the optical laminates of the above Examples and Comparative Examples was applied to the exposed surface exposed by separating the first base layer from the first laminates produced in Examples 1 and 2 and Comparative Examples 1 and 2. After forming an adhesive layer and cutting it into a size of 25 mm width x approximately 150 mm length, the adhesive layer surface was bonded to a glass plate to obtain a test sample (1). One end of a peeling tape with a width of 25 mm and a length of about 180 mm is pasted on one side of the second base layer surface of the test sample (1) with a width of 25 mm, and the other end is fixed to the grip of a tensile tester. A peel test was conducted to peel off the second base layer, and the peel force was measured. The peel test was conducted at a separation speed (crosshead speed (grabbing movement speed)) of 300 mm/min, 15000 mm/min, and 30000 mm/min, with a peel angle of 180° and a temperature of 23°C. The test was carried out in an environment with relative humidity of 50%. For the peel test when the separation speed is 300 m/min, "AGS-50NX" (manufactured by Shimadzu Corporation) is used as the above-mentioned tensile tester, and for the peel test when the separation speed is 15000 mm/min and 30000 mm/min, "TJ95-001" (manufactured by Imada Seisakusho Co., Ltd.) was used as the tensile tester.

(Peeling test of base material layer (X))
On the retardation layer (X) side of the retardation layer with base layer (X) used in Example 3 and Comparative Examples 3 and 4, the adhesive layer used in the production of the optical laminate of the above Example and Comparative Example was added. was formed and cut out into a size of 25 mm width x approximately 150 mm length, and the adhesive layer surface was bonded to a glass plate to obtain a test sample (2). Paste one end of a peeling tape with a width of 25 mm and a length of about 180 mm on one side of the 25 mm width of the surface of the base material layer (X) of the test sample (2), and fix the other end to the grip of the tensile testing machine. A peel test was conducted in which the base layer (X) was peeled off, and the peel force was measured. The peel test was conducted at a separation speed (crosshead speed (grabbing movement speed)) of 300 mm/min, 15000 mm/min, and 30000 mm/min, with a peel angle of 180° and a temperature of 23°C. The test was carried out in an environment with relative humidity of 50%. For the peel test when the separation speed is 300 m/min, "AGS-50NX" (manufactured by Shimadzu Corporation) is used as the above-mentioned tensile tester, and for the peel test when the separation speed is 15000 mm/min and 30000 mm/min, "TJ95-001" (manufactured by Imada Seisakusho Co., Ltd.) was used as the tensile tester.

(Evaluation of separation rate dependence)
In the peel test for the second base layer and the base layer (X), the peel force when the separation speed was 300 mm/min was P(0.3), and the peel force when the separation speed was 15000 mm/min was P(15). , the peeling force at 30,000 mm/min was defined as P(30), and the values of the ratio P(0.3)/P(15) and the ratio P(30)/P(15) were calculated. The closer the value of the ratio is to 1, the smaller the dependence of the peeling force on the separation rate when peeling off the second base layer or the base layer (X).

[Evaluation of retardation layer]
After the peel test, the surface of the second retardation layer side or the base material layer (X) side was visually observed to confirm the presence or absence of cracks.

・溶剤（シクロペンタノン）：９５部 [Comparative example 1 (comparative example of optical laminate having a first retardation layer and a second retardation layer)]
[Preparation of first retardation layer with base layer]
(Preparation of photoalignment layer forming composition (1))
A composition for forming a photo-alignment layer (1) was obtained by mixing the following components and stirring the resulting mixture at a temperature of 80° C. for 1 hour.
・Photoalignable material (compound represented by the following formula): 5 parts

・Solvent (cyclopentanone): 95 parts

・重合性液晶化合物Ａ２（下記式で表される化合物）：２０部

・重合開始剤（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））：６部
・溶剤（シクロペンタノン）：４００部 (Preparation of liquid crystal layer forming composition (A-1))
A composition for forming a liquid crystal layer (A-1) was obtained by mixing the following components and stirring the resulting mixture at 80° C. for 1 hour. 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 (compound represented by the following formula): 80 parts

・Polymerizable liquid crystal compound A2 (compound represented by the following formula): 20 parts

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

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

Subsequently, the composition for forming a liquid crystal layer (A-1) was applied onto the photoalignment layer using a bar coater, and after drying at 120°C for 1 minute, a high-pressure mercury lamp (Unicure VB-15201BY-A, Ushio The first liquid crystal layer was formed by irradiating ultraviolet rays (under nitrogen atmosphere, wavelength: 365 nm, irradiation intensity at wavelength 365 nm: 10 mW/cm ² , cumulative light amount: 2000 mJ/cm ² ) using a UV light source (manufactured by Denki Co., Ltd.). Thus, a first retardation layer with a base material layer was obtained. The thickness of the obtained first liquid crystal layer was measured using a laser microscope (LEXT, manufactured by Olympus Corporation), and the thickness was 2.0 μm. When the PET film (first base layer) is separated from the first retardation layer with a base layer, the peeling interface is between the photoalignment layer and the first liquid crystal layer, and the first retardation layer (first liquid crystal layer) The thickness of the first retardation layer was 2.0 μm, and the puncture elastic modulus E1 of the first retardation layer was 39.9 g/mm.

[Preparation of second retardation layer (1) with base material layer]
(Preparation of alignment layer forming composition (2))
A composition for forming an alignment layer (2) was obtained by adding 2-butoxyethanol to Sunever SE-610 (manufactured by Nissan Chemical Industries, Ltd.), which is a commercially available alignment polymer. The obtained alignment layer forming composition (2) had a solid content of 1% with respect to the total amount of the composition, and a solvent content of 99% with respect to the total amount of the composition. The solid content of Sunever SE-610 was calculated from the concentration stated in the delivery specifications.

・重合開始剤（イルガキュア（登録商標）９０７、ＢＡＳＦジャパン社製）：０．５％：
・反応添加剤（Ｌａｒｏｍｅｒ（登録商標）ＬＲ－９０００、ＢＡＳＦジャパン社製）：１．１％
・溶剤（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）：７９．１％ (Preparation of liquid crystal layer forming composition (B-1))
The following components were mixed, the resulting mixture was stirred at 80° C. for 1 hour, and then cooled to room temperature to obtain a composition for forming a liquid crystal layer (B-1).
・Polymerizable liquid crystal compound (LC242, manufactured by BASF): 19.2%

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

(Preparation of second retardation layer (1) with base material layer)
A polyethylene terephthalate (PET) film (second base layer) with a thickness of 38 μm was processed once using a corona treatment device (AGF-B10, manufactured by Kasuga Denki Co., Ltd.) at an output of 0.3 kW and a processing speed of 3 m/min. Processed. The composition for forming an alignment layer (2) was coated with a bar coater on the corona-treated surface and dried at 90° C. for 1 minute to obtain an alignment layer (second alignment layer). The thickness of the obtained alignment layer was measured using a laser microscope (LEXT, manufactured by Olympus Corporation) and was found to be 2.2 μm.

Subsequently, the composition for forming a liquid crystal layer (B-1) was applied onto the alignment layer using a bar coater, and after drying at 90°C for 1 minute, a high-pressure mercury lamp (Unicure VB-15201BY-A, Ushio Inc. Co., Ltd.) to form a second liquid crystal layer by irradiating ultraviolet rays (under nitrogen atmosphere, wavelength: 365 nm, cumulative light amount at wavelength 365 nm: 1000 mJ/cm ² ), and then form a second liquid crystal layer with a base material layer. A retardation layer (1) was obtained. The thickness of the second liquid crystal layer in the second retardation layer with base material layer (1) was 0.8 μm. When the PET film (second base layer) is separated from the second retardation layer with base layer (1), the peeling interface is between the PET film and the alignment layer, and the second retardation layer (the alignment layer and the second base layer) The thickness of the second liquid crystal layer was 3.0 μm, and the puncture elastic modulus E2 of the second retardation layer was 36.0 g/mm.

[Preparation of optical film]
A polarizing plate having protective layers on both sides of a linearly polarizing layer was prepared as an optical film.

[Preparation of adhesive composition]
After mixing the cationic curable components a1 to a3 shown in [a] to [c] below, and the cationic polymerization initiator and sensitizer shown in [d] and [e] below, defoaming is performed, and photocuring is performed. A mold adhesive composition was prepared. The numbers shown below are the amounts of each material in the adhesive composition.
[a] Cationic curable component a1
3',4'-Epoxycyclohexylmethyl 3',4'-epoxycyclohexane carboxylate (product name: CEL2021P, manufactured by Daicel Corporation): 70 parts (solid content)
[b] Cationic curable component a2
Neopentyl glycol diglycidyl ether (product name: EX-211, manufactured by Nagase ChemteX Corporation): 20 parts (solid content)
[c] Cationic curable component a3
2-Ethylhexyl glycidyl ether (trade name: EX-121, manufactured by Nagase ChemteX Corporation): 10 parts (solid content)
[d] Cationic polymerization initiator 50% propylene carbonate solution of product name "CPI-100" (manufactured by San-Apro Co., Ltd.): 2.25 parts (solid content)
[e] Sensitizer 1,4-diethoxynaphthalene: 2 parts (solid content)

(Preparation of first laminate)
Corona treatment (treatment conditions: 800 W, 10 m/min, bar width 700 mm, 1 pass). The adhesive composition prepared above is applied to the corona-treated surface of the first retardation layer with the base layer using a coating machine (Bar Coater, manufactured by Daiichi Rika Co., Ltd.) to form an adhesive composition layer. was formed. This adhesive composition layer and the corona-treated surface of the second retardation layer with base layer (1) were bonded together using a bonding device (LPA3301, manufactured by Fujipla Co., Ltd.). After that, from the second base layer side of the second retardation layer (1) with a base layer, UV irradiation equipment with a belt conveyor (the lamp used is "H Bulb" manufactured by Fusion UV Systems) is used to apply UVA radiation. In the UVB region, ^the irradiation intensity was 390 mW/cm ² and the cumulative light amount was 420 mJ/cm ² , and in the UVB region ^, the adhesive composition was The material layer was cured to obtain a first laminate.

Using the first laminate, the dependence of the peeling force on the separation rate was evaluated according to the procedure for measuring the peeling force of the second base layer. The results are shown in Table 1.

(Preparation of optical laminate)
The first base layer is separated from the first laminate, and the exposed surface exposed by separating the first base layer and the optical film are bonded to an adhesive layer (manufactured by Lintec Corporation) having a storage modulus shown in Table 1. An optical laminate was obtained by laminating them together via "NCF #L2" (sheet-like adhesive having a thickness of 5 μm). The peeling interface when the first base layer was separated from the first laminate was between the first alignment layer and the first liquid crystal layer.

[Example 1 (Optical laminate 1)]
[Preparation of second retardation layer (2) with base material layer]
(Preparation of liquid crystal layer forming composition (B-2))
The composition for forming a liquid crystal layer (B-2) was prepared in the same manner as the composition for forming a liquid crystal layer (B-1) except that the reaction additive (Laromer (registered trademark) LR-9000) was not included. Prepared.

(Preparation of second retardation layer (2) with base material layer)
Except that the composition for forming a liquid crystal layer (B-2) was applied on the alignment layer instead of the composition for forming a liquid crystal layer (B-1), and the cumulative amount of light in the subsequent ultraviolet irradiation was 700 mJ/cm ² A second retardation layer with a base layer (2) was obtained using the same procedure as the second retardation layer with a base layer (1). The thickness of the second liquid crystal layer in the second retardation layer with a base material layer (2) was 0.8 μm. When the PET film (second base layer) is separated from the second retardation layer with base layer (2), the peeling interface is between the alignment layer and the second liquid crystal layer, and the second retardation layer (second The thickness of the liquid crystal layer (liquid crystal layer) was 0.8 μm, and the puncture modulus E2 of the second retardation layer was 8.2 g/mm.

(Production of first laminate and optical laminate)
A first laminate and an optical laminate were obtained in the same manner as in Comparative Example 1, except that the second retardation layer with a base material layer (2) was used in place of the second retardation layer (1). Ta.

[Example 2 (Optical laminate 1)]
In place of the adhesive layer used in the production of the optical laminate in Example 1, an adhesive layer having the storage modulus shown in Table 1 ("P-3132" manufactured by Lintec Corporation, sheet-like adhesive with a thickness of 25 μm) was used. A first laminate and an optical laminate were obtained in the same manner as in Example 1 except that the following was used.

[Comparative example 2 (comparative example of optical laminate having a first retardation layer and a second retardation layer)]
Instead of the adhesive layer used in the production of the optical laminate of Comparative Example 1, an adhesive layer having the storage modulus shown in Table 1 ("P-3132" manufactured by Lintec Corporation, sheet-like adhesive with a thickness of 25 μm) was used. An optical laminate was obtained in the same manner as in Comparative Example 1 except that .

[Example 3 (Optical laminate 2)]
The second retardation layer with a base material layer (2) obtained in Example 1 was used as the retardation layer with a base material layer (X). Using the retardation layer with a base material layer (X), the separation rate dependence of the peeling force was evaluated according to the procedure for measuring the peeling force of the retardation layer (X). The results are shown in Table 2.

Corona treatment (processing conditions: 800W, 10m/min, bar width 700mm, 1Pass) was performed on the surface of the retardation layer (X) side of the retardation layer (X) with a base material layer, and the corona treatment surface and Comparative Example 1 were An optical laminate was obtained by laminating the prepared optical film through an adhesive layer ("NCF #L2" manufactured by Lintec Corporation, sheet adhesive with a thickness of 5 μm) having a storage modulus shown in Table 2. Ta.

[Comparative Example 3 (Optical laminate having retardation layer (X))]
An optical laminate was obtained in the same manner as in Example 3, except that the second retardation layer with a base material layer (1) obtained in Comparative Example 1 was used.

[Comparative Example 4 (Optical laminate having retardation layer (X))]
Using the second retardation layer with a base material layer (1) obtained in Comparative Example 1, an adhesive having a storage modulus shown in Table 2 was used in place of the adhesive layer used in the production of the optical laminate in Example 3. An optical laminate was obtained in the same manner as in Example 3, except that an adhesive layer ("P-3132" manufactured by Lintec Corporation, sheet-like adhesive with a thickness of 25 μm) was used.

1, 1a, 1b, 1c, 1d optical laminate, 10 first retardation layer, 11 first alignment layer, 12 first liquid crystal layer, 15 first base layer, 18 first retardation layer with base layer, 20 second retardation layer (retardation layer (X)), 21 second alignment layer (alignment layer (X)), 22 second liquid crystal layer (liquid crystal layer (X)), 25 second base material layer (base material layer (X)), 28 second retardation layer with base layer (retardation layer with base layer (X)), 31 adhesive layer, 32 lamination layer, 40 optical film, 50 retardation layer (X) , 51 alignment layer (X), 52 liquid crystal layer (X), 55 base material layer (X), 61 first laminate, 62 second laminate, 63 third laminate, 64 fourth laminate.

Claims (18)

An optical laminate comprising an optical film, an adhesive layer, and a retardation layer-containing layer including a retardation layer (X) in this order,
The retardation layer (X) is
disposed at the farthest position from the adhesive layer in the retardation layer-containing layer,
A laminate of a liquid crystal layer (X) which is a cured layer of a polymerizable liquid crystal compound and an alignment layer (X), and
An optical laminate having a puncture modulus E(X) of 12 g/mm or less. The optical laminate according to claim 1, wherein the alignment layer (X) is provided on a side of the liquid crystal layer (X) opposite to the adhesive layer side. Furthermore, a base material layer (X) is provided on a side opposite to the adhesive layer side of the retardation layer (X),
The optical laminate according to claim 1 or 2, wherein the base layer (X) is provided so as to be separable between the base layer (X) and the liquid crystal layer (X). The retardation layer-containing layer includes a first retardation layer, a bonding layer, and a second retardation layer in this order from the adhesive layer side,
The first retardation layer includes a first liquid crystal layer that is a cured layer of a polymerizable liquid crystal compound,
The optical laminate according to claim 1, wherein the second retardation layer is the retardation layer (X). The optical laminate according to claim 4, wherein the first retardation layer is a laminate of the first liquid crystal layer and a first alignment layer. The optical laminate according to claim 4 or 5, wherein the first retardation layer has a puncture modulus E1 of 15 g/mm or less. The optical laminate according to any one of claims 4 to 6, wherein the bonding layer is a cured adhesive layer. The optical laminate according to any one of claims 1 to 3, wherein the retardation layer-containing layer is the retardation layer (X). The optical laminate according to claim 1, wherein the adhesive layer has a storage modulus of 3.0×10 ⁶ N/m ² or less at a temperature of 23° C. The optical laminate according to claim 1, wherein the adhesive layer has a storage modulus of 6.0×10 ⁵ N/m ² or less at a temperature of 80° C. The optical laminate according to any one of claims 1 to 10, wherein the optical film includes a polarizing plate in which a protective layer is provided on one or both sides of a linearly polarizing layer. A method for producing an optical laminate comprising an optical film, an adhesive layer, and a retardation layer-containing layer including a retardation layer (X) in this order,
A step of preparing a base layer-attached retardation layer (X) having a base layer (X) and the retardation layer (X);
Using the optical film, the adhesive layer, and the base layer-attached retardation layer (X), the optical film, the adhesive layer, the retardation layer-containing layer, and the base layer (X ) in this order;
Peeling the base layer (X) from the laminate,
The retardation layer (X) is
disposed at the farthest position from the adhesive layer in the retardation layer-containing layer,
A liquid crystal layer (X) formed by polymerizing a polymerizable liquid crystal compound on the base layer (X), and
The piercing elastic modulus E(X) is 12 g/mm or less,
The method for producing an optical laminate, wherein the base layer-attached retardation layer (X) has an alignment layer between the base layer (X) and the liquid crystal layer (X) . The retardation layer-containing layer includes a first retardation layer, a bonding layer, and a second retardation layer in this order from the adhesive layer side,
The first retardation layer includes a first liquid crystal layer formed by polymerizing a polymerizable liquid crystal compound on a first base layer,
The method for manufacturing an optical laminate according to claim 12, wherein the second retardation layer is the retardation layer (X). The step of preparing the laminate includes:
preparing a first retardation layer with a base material layer having the first base layer and the first retardation layer;
The first retardation layer side of the first retardation layer with a base material layer and the retardation layer (X) side of the retardation layer with a base material layer (X) are bonded via the bonding layer. The process of matching,
A step of separating the first base material layer after the step of laminating via the laminating layer;
The method for producing an optical laminate according to claim 13, comprising the step of bonding the exposed surface exposed by separating the first base layer and the optical film via the adhesive layer. . The step of preparing the laminate includes:
preparing a first retardation layer with a base material layer having the first base layer and the first retardation layer;
bonding the optical film and the first retardation layer side of the first retardation layer with a base material layer via an adhesive layer;
A step of separating the first base layer after the step of bonding via the adhesive layer,
A step of laminating the exposed surface exposed by separating the first base layer and the retardation layer (X) side of the base layer-attached retardation layer (X) via the lamination layer. The method for manufacturing an optical laminate according to claim 13, comprising: The method for manufacturing an optical laminate according to claim 15, wherein the first retardation layer has a puncture modulus E1 of 15 g/mm or less. The optical laminate according to any one of claims 14 to 16, wherein the first retardation layer with a base material layer has a first alignment layer between the first base layer and the first liquid crystal layer. How the body is manufactured. The retardation layer-containing layer is the retardation layer (X),
The step of preparing the laminate includes:
The optical system according to claim 12, comprising a step of laminating the optical film and the retardation layer (X) side of the base layer-attached retardation layer (X) via the adhesive layer. Method for manufacturing a laminate.

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