CN114839710A

CN114839710A - Optical laminate

Info

Publication number: CN114839710A
Application number: CN202210113462.9A
Authority: CN
Inventors: 北河佑介; 幡中伸行
Original assignee: Sumitomo Chemical Co Ltd
Current assignee: Sumitomo Chemical Co Ltd
Priority date: 2021-02-01
Filing date: 2022-01-29
Publication date: 2022-08-02
Also published as: KR20220111196A; TW202241697A; JP2022117718A; JP7130789B2

Abstract

An object of the present invention is to provide an optical laminate which can suppress the occurrence of a zipper phenomenon and the lifting of a peeling interface at the time of transfer to a transfer target body, and which can be easily transferred to an arbitrary transfer target body. The optical laminate of the present invention comprises a1 st substrate, an alignment film, a polarizing film, an adhesive layer, a phase difference film and a2 nd substrate in this order, wherein the polarizing film and the phase difference film are each a cured film of a liquid crystal composition containing a liquid crystal compound, and a peeling force F1 when the 1 st substrate is peeled from the optical laminate and a peeling force F2 when the 2 nd substrate is peeled from the optical laminate satisfy formulae (1), (2) and (3): f1 not less than 0.02(N/25mm) not less than 0.30(N/25mm) (1) F2 not less than 0.30(N/25mm) (2) F1-F2 (3) not less than 0.02(N/25 mm).

Description

Optical laminate

Technical Field

The present invention relates to an optical laminate capable of double-sided transfer, a method for producing the optical laminate, an elliptically polarizing plate comprising the optical laminate, and a flexible display material.

Background

Circularly polarizing plates including a polarizing film and a phase difference film are widely used in Flat Panel Displays (FPDs) such as organic EL displays. As such a circularly polarizing plate, an optical laminate in which a polarizing film or a retardation film is an optically anisotropic layer formed of a coating layer obtained by coating a polymerizable liquid crystal compound on a substrate and polymerizing the same is known (patent documents 1 to 3).

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2020 and 56834

Patent document 2: japanese laid-open patent publication No. 2019-91088

Patent document 3: japanese patent laid-open No. 2020 and 13164

Disclosure of Invention

Problems to be solved by the invention

The optical laminate as disclosed in the above patent document can be incorporated into a display device or the like by transferring an optically anisotropic layer formed on a substrate to a transfer target, that is, by peeling the substrate and bonding the substrate to the transfer target via an adhesive layer or the like.

However, according to the studies of the present inventors, it was found that an optical laminate in which 2 outer layer surfaces developed by peeling off a base material from such an optical laminate are individually transferred and incorporated into a display device or the like sometimes causes a zipper phenomenon (Japanese: ジツピング) and lifting of a peeling interface at the time of transfer, and these phenomena can cause a reduction in the optical performance of the optical laminate after transfer.

An object of the present invention is to provide an optical laminate which can suppress the occurrence of a zipper phenomenon and the lifting of a peeling interface at the time of transfer to a transfer target body, and which can be easily transferred to an arbitrary transfer target body.

Means for solving the problems

The present inventors have conducted extensive studies to solve the above problems, and as a result, the present invention has been completed. That is, the present invention includes the following embodiments.

[1] An optical laminate comprising a1 st substrate, an alignment film, a polarizing film, an adhesive layer, a retardation film and a2 nd substrate in this order,

the polarizing film and the phase difference film are respectively a cured film of a polymerizable liquid crystal composition containing a polymerizable liquid crystal compound,

the peeling force F1 when the 1 st base material is peeled from the optical laminate and the peeling force F2 when the 2 nd base material is peeled from the optical laminate satisfy the formulae (1), (2) and (3):

0.02(N/25mm)≤F1≤0.30(N/25mm) (1)

0.02(N/25mm)≤F2≤0.30(N/25mm) (2)

0.02(N/25mm)≤|F1-F2| (3)。

[2] the optical laminate according to the above [1], wherein a peeling force adjusting layer is provided on at least one of a surface of the 1 st base material on the polarizing film side and a surface of the 2 nd base material on the retardation film side.

[3] The optical laminate according to the above [2], wherein the peeling force adjusting layer is a layer containing a silane compound or a hard coat layer.

[4] The optical laminate according to any one of the above [1] to [3], wherein the thickness of the 1 st base material is 20 μm or more and 100 μm or less.

[5] The optical laminate according to any one of the above [1] to [4], wherein the thickness of the 2 nd base material is 20 μm or more and 100 μm or less.

[6] The optical laminate according to any one of the above [1] to [5], wherein the 1 st base material is a resin film formed of at least 1 selected from a cellulose-based resin, a cycloolefin-based resin, and a polyethylene terephthalate resin.

[7] The optical laminate according to any one of the above [1] to [6], wherein the 2 nd substrate is a resin film formed of at least 1 selected from a cellulose-based resin, a cycloolefin-based resin, and a polyethylene terephthalate resin.

[8] The optical laminate according to any one of the above [1] to [7], wherein the polarizing film is a cured film of a polymerizable liquid crystal composition comprising a polymerizable liquid crystal compound and a dichroic dye.

[9] The optical laminate according to any one of the above [1] to [8], wherein the retardation film satisfies formula (4):

120nm≤Re(550)≤170nm (4)

[ in the formula, Re (λ) represents an in-plane retardation value of the retardation film at a wavelength of λ nm ].

[10] The optical laminate according to the above [9], further comprising a liquid crystal cured film as a positive C plate.

[11] The optical laminate according to any one of the above [1] to [10], wherein a total film thickness of the polarizing film, the adhesive layer and the retardation film is 20 μm or less.

[12] A method of manufacturing a long-sized optical film, the method comprising:

a step of manufacturing a long optical laminate roll in which the optical laminate according to any one of [1] to [11] is wound in a roll shape; and

and a1 st peeling step of continuously peeling, from the long optical laminate roll, one of the 1 st base material and the 2 nd base material constituting the optical laminate, which has a smaller peeling force when peeled from the optical laminate.

[13] The method for manufacturing a long optical film according to [12], further comprising:

a bonding step of bonding a3 rd substrate via an adhesive layer to a surface adjacent to the substrate peeled in the 1 st peeling step; and

and a2 nd stripping step of stripping the 1 st substrate or the 2 nd substrate which is not stripped in the 1 st stripping step.

[14] An elliptically polarizing plate comprising the optical laminate according to any one of [1] to [11 ].

[15] A flexible display material comprising the optical laminate according to any one of [1] to [11 ].

Effects of the invention

According to the present invention, it is possible to provide an optical laminate which can suppress the occurrence of a zipper phenomenon and the lifting of a peeling interface at the time of transfer to an object to be transferred, and which can be easily transferred to an arbitrary object to be transferred.

Drawings

Fig. 1 is a schematic cross-sectional view showing an example of the layer structure of the optical laminate of the present invention.

Fig. 2 is a schematic cross-sectional view showing an example of the layer structure of the optical laminate of the present invention.

Description of the reference numerals

1 st substrate, 2 oriented film, 3 polarizing film, 4 th adhesive bonding layer, 5 th phase difference film, 6 oriented film, 7 nd substrate, 8, 9 peeling force adjusting layer, 11 optical laminated body, 12 laminated body structure.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail. The scope of the present invention is not limited to the embodiments described herein, and various modifications can be made without departing from the spirit of the present invention.

The optical laminate of the present invention comprises a1 st substrate, an alignment film, a polarizing film, an adhesive layer, a retardation film, and a2 nd substrate in this order. An example of the layer structure of the optical laminate of the present invention will be described below with reference to fig. 1 and 2, but the laminate of the present invention is not limited to these embodiments.

The optical laminate 11 shown in fig. 1 is formed by laminating a1 st substrate 1, an alignment film 2, a polarizing film 3, an adhesive layer 4, a retardation film 5, an alignment film 6, and a2 nd substrate 7 in this order. In the optical laminate 11 shown in fig. 1, the 1 st substrate 1 and the 2 nd substrate 7 are each peelable, and the 1 st substrate and the 2 nd substrate that are peelable can be peeled from the optical laminate 11, and the laminate structure 12 including the alignment film 2, the polarizing film 3, the adhesive layer 4, the retardation film 5, and the alignment film 6 is transferred to a transfer-receiving object such as a (flexible) OLED or a (flexible) touch panel.

In a preferred embodiment of the present invention, the optical laminate of the present invention includes a peeling force adjusting layer on at least one of a surface of the 1 st substrate on the polarizing film side and a surface of the 2 nd substrate on the retardation film side. The optical laminate 12 shown in fig. 2 has a peeling force adjusting layer 8 between the 1 st substrate 1 and the alignment film 2, and has a peeling force adjusting layer 9 between the 2 nd substrate 7 and the alignment film 6. In one embodiment of the present invention, only the peeling force adjusting layer is disposed between the 1 st substrate and the alignment film, and in another embodiment, only the peeling force adjusting layer and the alignment film are disposed between the 2 nd substrate and the retardation film.

The optical laminate of the present invention may be configured to include other layers in addition to the 1 st substrate, the alignment film, the polarizing film, the adhesive layer, the retardation film, the 2 nd substrate, and the peeling force adjusting layer, as long as the effects of the present invention are not affected. Examples of the other layers include an alignment film for forming a retardation film, a second retardation film, an adhesive layer other than the adhesive layer between the polarizing film and the retardation film, and a resin layer having UV absorbing ability.

In the optical laminate of the present invention, the peeling force F1 when the 1 st base material is peeled from the optical laminate and the peeling force F2 when the 2 nd base material is peeled from the optical laminate satisfy the formulae (1), (2) and (3):

0.02(N/25mm)≤F1≤0.30(N/25mm) (1)

0.02(N/25mm)≤F2≤0.30(N/25mm) (2)

0.02(N/25mm)≤|F1-F2| (3)。

when the peeling force F1 and the peeling force F2 are in the specific ranges of the above formula (1) or formula (2), respectively, and the peeling force F1 and the peeling force F2 are in the relationship shown in the above formula (3), the zipper phenomenon and the occurrence of lifting at the peeling interface can be suppressed when 2 outer layer surfaces appearing after peeling off the base material from the optical laminate are transferred to be incorporated into a display device, respectively, and an effect of suppressing the decrease in optical performance due to the transfer can be expected.

In the present invention, the peel force F1 is preferably less than 0.30N/25mm, more preferably 0.25N/25mm or less, and still more preferably 0.15N/25mm or less. If the upper limit of the peeling force F1 is within the above range, the 1 st base material is easily peeled from the optical laminate, and the peeling force F1 is easily controlled in a range effective for suppressing the occurrence of the zipper phenomenon and the lifting in the relationship with the peeling force F2. The peel force F1 is preferably 0.04N/25mm or more, more preferably 0.06N/25mm or more, and still more preferably 0.08N/25mm or more. When the peeling force F1 is not less than the lower limit, it is possible to suppress unintended peeling of the 1 st substrate before transfer, which is incorporated in a display device or the like, while ensuring easy peeling when peeling the 1 st substrate from the optical laminate.

In the present invention, the peel force F2 is preferably less than 0.30N/25mm, more preferably 0.25N/25mm or less, and still more preferably 0.15N/25mm or less. If the upper limit of the peeling force F2 is within the above range, the 2 nd base material is easily peeled from the optical laminate, and the peeling force F2 is easily controlled in a range effective for suppressing the occurrence of the zipper phenomenon and the lifting in the relationship with the peeling force F1. The peel force F2 is preferably 0.04N/25mm or more, more preferably 0.06N/25mm or more, and still more preferably 0.08N/25mm or more. When the peeling force F2 is not less than the lower limit, it is possible to suppress unintended peeling of the 2 nd substrate before transfer, which is incorporated in a display device or the like, while ensuring easy peeling when peeling the 2 nd substrate from the optical laminate.

When the peeling force F1 and the peeling force F2 satisfy the relationship expressed by the above expression (3), a moderate strength relationship is generated between the adhesion force of the 1 st base material of the optical laminate and the adhesion force of the 2 nd base material of the optical laminate. Therefore, when the above relationship is satisfied, the occurrence of the zipper phenomenon and the lift-off at the peeling interface at the time of transfer can be suppressed, and the 1 st substrate and the 2 nd substrate can be easily peeled from the optical laminate in a desired order. This can be expected to suppress the reduction in optical performance of the optical laminate due to transfer. In particular, the absolute value of F1 to F2 in the present invention is preferably 0.03N/25mm or more, and more preferably 0.04N/25mm or more, from the viewpoint of excellent effect of suppressing the occurrence of lift-off at the peeling interface. From the viewpoint of enhancing the effect of suppressing the occurrence of the zipper phenomenon, the upper limit of the absolute value of F1-F2 is usually 0.3N/25mm or less, preferably 0.2N/25mm or less, and more preferably 0.08N/25mm or less. The values of F1-F2 can be controlled by adjusting the peel force F1 and the peel force F2, respectively. The peel force F1 and the peel force F2 are generally designed such that the peel force of the substrate side peeled first is smaller than the peel force of the substrate side peeled later.

The peel forces F1 and F2 are measured as peel forces necessary for peeling the 1 st substrate or the 2 nd substrate, which is the object of measurement, from the optical laminate of the test piece, in which the surface of the optical laminate, from which the substrate opposite to the substrate from which the peel force is measured is peeled (for example, the 2 nd substrate in the case of measurement of F1 and the 1 st substrate in the case of measurement of F2), is fixed by bonding the substrate to a glass plate with an adhesive or the like. The peel force may be measured according to JIS K6854-1: 1999, 90 ° peel test method. The detailed measurement methods of the peeling forces F1 and F2 are described in the examples described later.

The peeling forces F1 and F2 can be adjusted by, for example, the constitution and thickness of the layer adjacent to each of the 1 st and 2 nd substrates, the type and thickness of the 1 st and 2 nd substrates, and the surface treatment of the 1 st and 2 nd substrates and/or the layer adjacent to these substrates. For example, the peeling force of the 1 st substrate or the 2 nd substrate from the optical laminate can be controlled by performing a modification treatment on the surface of the 1 st substrate and/or the 2 nd substrate as described later, or by providing a layer for controlling the peeling force to a desired range (hereinafter referred to as a "peeling force adjusting layer") as a layer adjacent to the 1 st substrate or the 2 nd substrate.

Hereinafter, each configuration of the optical laminate of the present invention will be described in detail.

[1 st and 2 nd substrates ]

The 1 st substrate and the 2 nd substrate are each a layer that can be laminated on the optical laminate in a peelable manner. The 1 st substrate and the 2 nd substrate may be any substrates that can satisfy the peeling forces F1 and F2 and satisfy the above formulas (1), (2), and (3), and for example, resin films and the like conventionally known in the field of optical films may be used. Examples of the resin forming the 1 st substrate and the 2 nd substrate include polyolefins such as polyethylene, polypropylene, and norbornene polymers; a cycloolefin resin; polyvinyl alcohol; polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polymethacrylates; a polyacrylate; cellulose resins such as triacetyl cellulose, diacetyl cellulose, and cellulose acetate propionate; a polycarbonate; polysulfones; polyether sulfone; a polyether ketone; plastics such as polyphenylene sulfide and polyphenylene oxide. Among them, from the viewpoint of smoothness and quality as a coated substrate, at least 1 kind selected from the group consisting of a cellulose-based resin, a cycloolefin-based resin, and a polyethylene terephthalate resin is preferable. These may be used alone, or 2 or more of them may be used in combination. Such a resin can be formed into a resin film by a known method such as a solvent casting method or a melt extrusion method. In the present specification, when only the "base material" is referred to, the "base material" includes the 1 st base material and the 2 nd base material.

In order to impart desired releasability and adhesiveness to the film surface and easily control the peeling forces F1 and F2 in desired ranges, the surface of the base material may be subjected to a modification treatment such as corona treatment, plasma treatment, or flame treatment depending on the structure of the adjacent layer. In the optical laminate of the present invention, when the surface modification treatment is performed on the 1 st substrate and the 2 nd substrate, the treatment methods may be the same as or different from each other.

The thickness of the 1 st substrate and the 2 nd substrate may be determined as appropriate depending on the structure of the 1 st substrate and the 2 nd substrate, the structure of the layer adjacent to the substrates, and the like, and each of the thicknesses is preferably 20 μm or more, more preferably 30 μm or more, further preferably 40 μm or more, and further preferably 120 μm or less, more preferably 100 μm or less, and further preferably 80 μm or less, from the viewpoint of the film surface quality at the time of coating and drying. In the optical laminate of the present invention, the thicknesses of the 1 st substrate and the 2 nd substrate may be the same as or different from each other.

The thickness of the substrate can be measured by a laser microscope, a film thickness meter, or the like, and the thickness of each layer or film such as a polarizing film, a retardation film, or the like constituting the optical laminate is also measured in the following manner.

[ peeling force adjusting layer ]

The optical laminate of the present invention preferably has a peeling force adjusting layer on at least one of the polarizing film side surface of the 1 st substrate and the retardation film side surface of the 2 nd substrate. By providing the peeling force adjusting layer, even in the case of a long optical laminate, a desired peeling force can be easily secured over the entire length thereof, and the effect of suppressing the zipper phenomenon and the lifting of the peeling interface can be easily enhanced. In the case where the optical laminate of the present invention includes the peeling force adjusting layer, the peeling force adjusting layer is usually disposed adjacent to the surface of the 1 st substrate on the polarizing film side or the surface of the 2 nd substrate on the retardation film side.

The peeling force adjusting layer in the present invention is a layer formed on the polarizing film side surface of the 1 st substrate and/or the retardation film side surface of the 2 nd substrate, and has a function of controlling the peeling force F1 when the 1 st substrate is peeled from the optical laminate and/or the peeling force F2 when the 2 nd substrate is peeled from the optical laminate. The peeling force adjusting layer may be a single layer or a plurality of layers of 2 or more. When the peeling force adjusting layer is formed of 2 or more layers containing different components, the peeling force F1 or the peeling force F2 may be easily controlled to a desired range, and a desired peeling force can be secured more stably over the entire length of the long optical laminate.

In the optical laminate of the present invention, the peeling force F1 and/or the peeling force F2 may be controlled by performing corona treatment, plasma treatment or the like on the surface of the substrate as described above, but in the present description, the "peeling force adjusting layer" is a layer formed independently on the surface of the 1 st substrate on the polarizing film side or on the surface of the 2 nd substrate on the retardation film side, and for example, when the surface itself of the 1 st substrate, the 2 nd substrate and/or a layer adjacent to these substrates is surface-modified by corona treatment, plasma treatment or the like, such a modified surface is not included in the "peeling force adjusting layer".

The peeling force adjusting layer can be formed, for example, by applying a composition for forming a peeling force adjusting layer containing a component capable of adjusting the adhesion of the substrate to the surface of the resin film serving as the substrate, the surface being adjacent to the substrate with the peeling force adjusting layer interposed therebetween. As the peeling force adjusting layer, any material or the like conventionally known in the art may be used as long as a desired peeling force can be secured. Examples of the composition for forming a peeling force adjusting layer capable of forming a peeling force adjusting layer in the present invention include a solution containing a silane compound; a solution containing silica powder or the like; a curable resin composition; and compositions containing release materials such as fluorine-based materials, long-chain alkyl-based materials, and fatty acid amide-based materials. Among them, from the viewpoint of easily forming a layer capable of imparting a desired peeling force, the peeling force adjusting layer preferably includes at least 1 layer selected from the group consisting of a layer containing a silane compound and a hard coat layer. In the present specification, the hard coat layer refers to a cured resin layer having higher surface smoothness than adjacent substrates and being peelable from the substrate.

The layer containing a silane compound, which can constitute the peeling force adjustment layer, is a layer containing a silane compound, and may be formed of a material known in the art as long as a desired peeling force F1 and/or peeling force F2 can be secured in the optical laminate.

Examples of the silane compound include silicon polymers such as polysilane, silicone resins such as silicone oil and silicone resin, silicone oligomers, organic-inorganic silane compounds such as silsesquioxane and alkoxysilane, and more specifically, nonionic compounds containing an Si element such as a silane coupling agent. These silane compounds may be used alone in 1 kind, or in combination with 2 or more kinds. Among them, a silane coupling agent is preferable.

The silane coupling agent is preferably a silane compound having at least 1 functional group selected from a vinyl group, an amino group, a ureido group, a mercapto group, a (meth) acryloyl group, an isocyanate group, an imidazole group and an epoxy group, and more preferably a compound containing an Si element having the at least 1 functional group and at least 1 alkoxysilyl group or silanol group. The vinyl group, the amino group, the ureido group, the mercapto group, the (meth) acryloyl group, the isocyanate group, the imidazolyl group and the epoxy group have polarity, and by appropriately selecting these functional groups, the adhesion between the base material and the layer laminated with the peeling force adjusting layer interposed therebetween can be controlled, and the peeling force F1 and/or the peeling force F2 can be easily controlled to a desired range. From this viewpoint, the silane coupling agent is preferably a silane coupling agent having an alkoxysilyl group and the at least 1 functional group. The functional group may be a substituent or a protecting group as appropriate for controlling the reactivity of the silane coupling agent.

Specific examples of the silane coupling agent include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N- (1, 3-dimethyl-butylidene) propylamine, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, 3-chloropropylmethyldimethoxysilane, and, 3-chloropropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropyldimethoxymethylsilane, and 3-glycidoxypropylethoxydimethylsilane.

Further, examples of commercially available silane coupling agents include silane coupling agents manufactured by shin-Etsu chemical industries (Ltd.) such as KP321, KP323, KP324, KP326, KP340, KP341, X22-161A, KF6001, KBM-1003, KBE-1003, KBM-303, KBM-402, KBM-403, KBE-402, KBE-403, KBM-1403, KBM-502, KBM-503, KBE-502, KBE-503, KBM-5103, KBM-602, KBM-603, KBM-903, KBE-9103, KBM-573, KBM-575, KBM-9659, KBE-585, KBM-802, KBM-803, KBE-846, and KBE-9007.

The layer containing a silane compound which functions as a peeling force adjusting layer can be formed, for example, from a solution containing a silane compound in which a silane compound is mixed and dissolved in an appropriate solvent.

The solvent used in the solution containing the silane compound may be appropriately selected depending on the solubility of the silane compound used, and the like. Specifically, examples thereof include water, alcohol solvents such as methanol, ethanol, ethylene glycol, isopropanol, propylene glycol, methyl cellosolve, butyl cellosolve, and propylene glycol monomethyl ether, ester solvents such as ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, γ -butyrolactone, propylene glycol methyl ether acetate, and ethyl lactate, ketone solvents such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, methyl amyl ketone, and methyl isobutyl ketone, aliphatic hydrocarbon solvents such as pentane, hexane, and heptane, aromatic hydrocarbon solvents such as toluene and xylene, nitrile solvents such as acetonitrile, ether solvents such as tetrahydrofuran and dimethoxyethane, and chlorinated hydrocarbon solvents such as chloroform and chlorobenzene. These solvents may be used alone or in combination of 2 or more.

The content of the silane compound in the solution containing the silane compound is preferably 0.01 mass% or more, more preferably 0.1 mass% or more, and still more preferably 0.25 mass% or more, with respect to the total mass of the solution containing the silane compound, from the viewpoint of easily controlling the peeling force. The content of the silane compound is preferably 30% by mass or less, more preferably 10% by mass or less, and further preferably 5% by mass or less, based on the total mass of the solution containing the silane compound.

The solution containing the silane compound may contain other components than the silane compound and the solvent as long as the solution can impart a desired peeling force to the 1 st substrate and/or the 2 nd substrate, but in one embodiment of the present invention, the solution containing the silane compound is substantially composed of the silane compound and the solvent.

The layer containing a silane compound which functions as a peeling force adjusting layer can be formed by, for example, applying a solution containing a silane compound to the surface of the 1 st substrate, the 2 nd substrate, or the like on which the peeling force adjusting layer is formed, and then drying and removing the solvent.

Examples of the method of applying the solution containing the silane compound to the surface on which the peeling force adjusting layer is formed include known methods such as a spin coating method, an extrusion method, a gravure coating method, a die coating method, a bar coating method, a coating method such as a coater method, and a printing method such as a flexographic method.

Examples of the drying method for removing the solvent contained in the coating film obtained from the solution containing the silane compound include a natural drying method, a forced air drying method, a heat drying method, a reduced pressure drying method, and the like. The conditions such as the drying temperature and the drying time can be appropriately determined depending on the composition of the solution containing the silane compound, the material of the surface (substrate) on which the peeling force adjusting layer is formed, and the like.

The thickness of the layer containing a silane compound which functions as a peeling force adjusting layer is usually 10nm to 1000nm, preferably 10nm to 500nm, and more preferably 30nm to 300 nm.

In the optical laminate of the present invention, the hard coat layer formed as the peeling force adjusting layer may be formed of a material known in the art as long as a desired peeling force F1 and/or peeling force F2 can be secured in the optical laminate, and examples thereof include a layer formed of a resin composition containing a water-soluble polymer and a cured resin layer formed of a resin composition containing an active energy ray-curable or thermosetting resin component. Among these, the cured resin layer formed from a resin composition containing an active energy ray-curable resin component is preferable, and the cured resin layer formed from a resin composition containing an active energy ray-curable resin component and a crosslinking agent is more preferable.

In the present invention, the resin composition for forming a hard coat layer generally contains a resin component (polymer). Examples of the resin component include resin components (polymers) such as (meth) acrylic polymers, urethane polymers, polyester polymers, silicone polymers, polyvinyl ether polymers, and polyvinyl alcohol polymers. These resin components can be used alone in 1, also can be combined with more than 2. Among them, the (meth) acrylic polymer and the urethane polymer are preferable, and the urethane acrylate polymer is more preferable.

Examples of the (meth) acrylic polymer include polymers and copolymers each containing 1or 2 or more kinds of (meth) acrylic esters such as butyl (meth) acrylate, ethyl (meth) acrylate, isooctyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate as monomers.

Examples of the urethane polymer include polyurethanes such as ether polyurethane, ester polyurethane, and carbonate polyurethane, and acrylic-urethane copolymers obtained by copolymerizing urethane (meth) acrylate and alkyl (meth) acrylate. By including the urethane polymer in the hard coat layer, the flexibility is easily improved, and an optical laminate suitable as a material for a flexible display is easily obtained. Polyurethanes such as ether-based polyurethanes, ester-based polyurethanes, and carbonate-based polyurethanes; an acrylic-urethane copolymer obtained by copolymerizing urethane (meth) acrylate and an alkyl (meth) acrylate.

The content of the resin component in the resin composition may be appropriately determined depending on the kind of the resin component used, but is preferably 50 parts by mass or more, more preferably 60 parts by mass or more, further preferably 70 parts by mass or more, and further preferably 100 parts by mass or less, more preferably 95 parts by mass or less, further preferably 90 parts by mass or less, relative to 100 parts by mass of the solid content of the resin composition.

The resin composition for forming a hard coat layer may include a crosslinking agent. As the crosslinking agent, those generally used in this field can be used, and can be appropriately selected depending on the resin component forming the hard coat layer, the structure of the layer adjacent to the hard coat layer, and the like. Examples of the crosslinking agent include methylol compounds, polyfunctional thiol compounds, polyfunctional (meth) acrylates, and the like. These may be used alone, or 2 or more of them may be used in combination. Among these, at least 1 kind selected from the group consisting of methylol compounds, polyfunctional thiol compounds and polyfunctional (meth) acrylate compounds is preferable, and polyfunctional (meth) acrylate compounds are more preferable.

Specific examples of the methylol compound include alkoxymethylated glycolurils such as 1, 3, 4, 6-tetrakis (methoxymethyl) glycoluril, 1, 3, 4, 6-tetrakis (butoxymethyl) glycoluril, 1, 3, 4, 6-tetrakis (hydroxymethyl) glycoluril, 1, 3-bis (hydroxymethyl) urea, 1, 3, 3-tetrakis (butoxymethyl) urea, 1, 3, 3-tetrakis (methoxymethyl) urea, 1, 3-bis (hydroxymethyl) -4, 5-dihydroxy-2-imidazolidinone, and 1, 3-bis (methoxymethyl) -4, 5-dimethoxy-2-imidazolidinone; alkoxymethylated benzoguanamines such as tetramethoxymethylbenzguanamine and tetrabutoxymethylbenzguanamine; and alkoxymethylated melamines such as hexamethoxymethylmelamine and hexabutoxymethylmelamine. Further, a melamine compound, a urea compound, a glycoluril compound, and a benzoguanamine compound, each of which has a hydrogen atom of an amino group substituted with a hydroxymethyl group or an alkoxymethyl group, may be condensed.

Commercially available methylol compounds may also be used. Commercially available products of alkoxymethylated glycolurils include glycoluril compounds (trade names CYMEL 1170 and Powderlink 1174) manufactured by Nippon Cytec Industries, methylated urea-formaldehyde resins (trade name UFR65) and butylated urea-formaldehyde resins (trade names UFR300, U-VAN10S60, U-VAN10R and U-VAN11HV), urea/formaldehyde resins (highly condensed type, trade names BECKAMINE J-300S, BECKAMINE P-955 and BECKAMINE N) manufactured by Dainippon ink chemical Industries, and butylated urea-formaldehyde resins (trade names BEAMINE P-138, BECKAMINE P-196-M and BECKAMINE G-1850). Commercially available products of alkoxymethylated benzoguanamine include those manufactured by Cytec Industries, Japan (trade name CYMEL 1123), and chemical products (trade names NIKALAC BX-4000, NIKALAC BX-37, NIKALAC BL-60, and NIKALAC BX-55H), and butylated benzoguanamine resins manufactured by Japan ink chemical Industries, Japan (trade name SUPER BECKAMINE TD-126, SUPER BECKAMINE 15-594). Commercially available products of alkoxymethylated melamine include methoxymethyl-type melamine compounds (trade names CYMEL 300, CYMEL 301, CYMEL 303, and CYMEL 350) manufactured by Nippon Cytec Industries, Inc., butoxymethyl-type melamine compounds (trade names MYCOAT 506 and MYCOAT 508), methoxymethyl-type melamine compounds (trade names NIKALAC MW-30, NIKALAC MW-22, NIKALAC MW-11, NIKALAC MS-001, NIKALAC MX-002, NIKALAC MX-730, NIKALAC MX-750, and NIKALAC MX-035), butoxymethyl-type melamine compounds (trade names NIKALAC MX-45, NIKALAC MX-410, and NIKALAC MX-302), butylated melamine resins (SUPER CKAME J-820-60 INAMINE J-60) manufactured by Dainippon ink chemical Industries, Inc, SUPER BECKAMINE L-109-65, SUPER BECKAMINE L-117-60, SUPER BECKAMINE L-127-60, SUPER BECKAMINE 13-548, SUPER BECKAMINE G-821-60, SUPER BECKAMINE L-110-60, SUPER BECKAMINE L-125-60, SUPER BECKAMINE L-166-60B), methylated melamine resin (trade name SUPER BECKAMINE L-105-60), and the like. In addition, aqueous melamine resins such as WATERSOL S-695 and S-683-IM, trade name BECKAMINE P-198, available from Dainippon ink chemical industries, Ltd. Further, as a commercially available product of the melamine compound, there may be mentioned a trade name CYMEL 303 (manufactured by Cytec Industries, japan), and the like, and as a commercially available product of such a benzoguanamine compound, there may be mentioned a trade name CYMEL 1123 (manufactured by Cytec Industries, japan).

The polyfunctional thiol compound is a compound having 2 or more thiol groups in 1 molecule. Examples of the polyfunctional thiol compound include hexanedithiol, decanedithiol, 1, 4-dimethylmercaptobenzene, butanediol dimercaptopropionate, butanediol dimercaptoacetate, ethylene glycol dimercaptoacetate, trimethylolpropane trimercaptoacetate, butanediol dimercaptopropionate, trimethylolpropane trimercaptopropionate, trimethylolpropane trimercaptoacetate, pentaerythritol tetramercaptopropionate, pentaerythritol tetramercaptoacetate, trihydroxyethyl trimercaptopropionate, pentaerythritol tetrakis (3-mercaptobutyrate), 1, 4-bis (3-mercaptobutyryloxy) butane, and the like.

The polyfunctional (meth) acrylate compound is a compound having 2 or more (meth) acryloyloxy groups in 1 molecule. In the present specification, "(meth) acrylate" means "acrylate" or "methacrylate", and "(meth) acryloyl group" means "acryloyl group" or "methacryloyl group" in the same manner.

Specific examples of the polyfunctional (meth) acrylate include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetradecanediol di (meth) acrylate, dipropylene glycol di (meth) acrylate, 1, 3-butanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylolmethane tetra (meth) acrylate, 1, 4-butanediol di (meth) acrylate, 1, 6-hexanediol di (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and the like.

When a polyfunctional (meth) acrylate compound is used as the crosslinking agent, the number of (meth) acryloyl groups is preferably 4 or more, more preferably 6 or more, preferably 10 or less, and more preferably 8 or less. When the number of (meth) acryloyl groups in the polyfunctional (meth) acrylate compound is not less than the lower limit, the crosslinking density of the hard coat layer is increased, and the hard coat layer can function not only as a peeling force adjusting layer but also as a protective layer for a polarizing film or a retardation film.

In the case of the polyfunctional (meth) acrylate compound, the crosslinking density of the hard coat layer can be adjusted by controlling the molecular weight between crosslinking points and the number of crosslinking points of the compound. More specifically, the smaller the molecular weight between crosslinking points, the higher the crosslinking density, and the larger the number of crosslinking points, the higher the crosslinking density, and the higher the function as a protective layer for a polarizing film or a retardation film, and particularly the heat resistance of the resulting optical laminate can be improved.

In one embodiment of the present invention, from the viewpoint that a hard coat layer which can also function as a protective layer of a polarizing film or a retardation film can be formed by controlling the crosslinking density, the polyfunctional (meth) acrylate compound preferably has a branched structure, and the number of atoms of a chain (sometimes referred to as a connecting chain) connecting a branching point closest to a (meth) acryloyl group in the branched structure and the (meth) acryloyl group is preferably 3 or less, and more preferably 2 or less. When the number of atoms is not more than the above upper limit, the crosslinking density of the hard coat layer becomes high, and improvement of the heat resistance of the optical laminate can be expected. When a plurality of such linking chains are present, at least 1 linking chain may satisfy the above-mentioned range of the number of atoms, and from the viewpoint of improving heat resistance, it is preferable that all the linking chains satisfy the above-mentioned range of the number of atoms.

The content of the crosslinking agent in the resin composition for forming a hard coat layer may be appropriately determined depending on the kind of the crosslinking agent used, but is preferably 50 parts by mass or more, more preferably 60 parts by mass or more, further preferably 70 parts by mass or more, and further preferably 100 parts by mass or less, more preferably 95 parts by mass or less, further preferably 90 parts by mass or less, relative to 100 parts by mass of the solid content of the resin composition. If the content of the crosslinking agent is within the above range, the release force F1 and/or the release force F2 can be easily controlled to a desired range.

The resin composition for forming a hard coat layer may contain a polymerization initiator from the viewpoint of enhancing curability and the like. The polymerization initiator may be appropriately selected from known photopolymerization initiators and thermal polymerization initiators so as to initiate curing of the curable compound (resin) contained in the resin composition, but is preferably used from the viewpoint of improving productivity. Examples of the photopolymerization initiator include acetophenone initiators such as acetophenone, 3-methylacetophenone, benzildimethylketal, 1- (4-isopropylphenyl) -2-hydroxy-2-methyl-1-propanone, 2-methyl-1- [4- (methylthio) phenyl ] -2-morpholinyl-1-propanone, and 2-hydroxy-2-methyl-1-phenyl-1-propanone; benzophenone-based initiators such as benzophenone, 4-chlorobenzophenone and 4, 4' -diaminobenzophenone; an alkylbenzene-based initiator such as 2, 2-dimethoxy-1, 2-diphenyl-1-ethanone or 1-hydroxycyclohexyl phenyl ketone; benzoin ether-based initiators such as benzoin propyl ether and benzoin ethyl ether; thioxanthone initiators such as 4-isopropylthioxanthone; acylphosphine oxide-based initiators such as bis (2, 4, 6-trimethylbenzoyl) -phenylphosphine oxide; and xanthone, fluorenone, camphorquinone, benzaldehyde, anthraquinone, etc. These may be used alone, or 2 or more of them may be used in combination.

The amount of the polymerization initiator in the resin composition for forming the hard coat layer is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and further preferably 10 parts by mass or less, more preferably 8 parts by mass or less, per 100 parts by mass of the solid content of the resin composition. When the content of the polymerization initiator is within the above range, sufficient curability can be obtained without affecting the optical performance of the optical laminate.

The resin composition for forming a hard coat layer may contain, if necessary, other additives other than the polymerization initiator, for example, an ultraviolet absorber, an antistatic agent, a stabilizer, an antioxidant, a colorant, a surface conditioner, and the like. Other additives may be used alone, or 2 or more of them may be used in combination. When other additives are contained, the content thereof is preferably about 0.1 to 20% by mass relative to the total mass of the solid components of the resin composition.

In order to improve coatability, the viscosity can be adjusted by adding a solvent to the resin composition forming the hard coat layer. The solvent may be any solvent that can dissolve the various components forming the resin composition, and examples thereof include the same solvents as those exemplified as the solvent used in the solution containing the silane compound.

The type and content of the solvent may be appropriately selected depending on the type, content, shape, coating method, thickness of the hard coat layer, and the like of the components contained in the resin composition, and for example, the content of the solvent is preferably 3 parts by mass or more, more preferably 5 parts by mass or more, further preferably 7 parts by mass or more, and further preferably 1000 parts by mass or less, more preferably 100 parts by mass or less, further preferably 50 parts by mass or less with respect to 100 parts by mass of the solid content of the resin composition.

The hard coat layer functioning as the peeling force adjusting layer can be obtained by, for example, applying a resin composition to a surface of the substrate or another peeling force adjusting layer on which the hard coat layer is formed, and curing the resin composition. As a method for applying the resin composition, the same method as that for applying a solution containing a silane compound to a substrate or the like can be used.

The method of curing the resin composition may be determined appropriately according to the composition of the resin composition. For example, in the case where the resin composition is an active energy ray-curable composition, the curable components contained in the composition can be cured by irradiation with active energy rays to obtain a hard coat layer. Examples of the active energy ray include visible light, ultraviolet light, infrared light, X-ray, α -ray, β -ray, and γ -ray. Among them, ultraviolet light is preferable in terms of easy control of the progress of the reaction and the availability of a photopolymerization device widely used in this field.

Examples of the light source of the active energy ray include a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a xenon lamp, a halogen lamp, a carbon arc lamp, a tungsten lamp, a gallium lamp, an excimer laser, an LED light source emitting light having a wavelength range of 380 to 440nm, a chemical lamp, a black light lamp, a microwave-excited mercury lamp, and a metal halide lamp.

The ultraviolet irradiation intensity is usually 10-3000 mW/cm ² . The ultraviolet irradiation intensity is preferably an intensity in a wavelength region effective for activation of the polymerization initiator. The time for irradiating light is usually 0.1 second to 10 minutes, preferably 1 second to 5 minutes, more preferably 5 seconds to 3 minutes, and further preferably 10 seconds to 1 minute. When the ultraviolet irradiation intensity is applied for 1or more times, the cumulative light amount is 10 to 3000mJ/cm ² Preferably 50 to 2000mJ/cm ² More preferably 100 to 1000mJ/cm ² 。

The thickness of the hard coat layer functioning as the peeling force adjusting layer is usually 0.1 to 10 μm, preferably 0.2 μm or more, more preferably 0.3 μm or more, and preferably 5 μm or less, more preferably 3 μm or less.

The structure of the peeling force adjusting layer may be determined appropriately according to the type of the 1 st base material or the 2 nd base material, the relationship with the layer adjacent to these base materials with the peeling force adjusting layer interposed therebetween, and the like. For example, by using a resin film formed of polyethylene terephthalate as the resin film forming the substrate and forming a peeling force adjusting layer formed of an acrylic silane coupling agent as the peeling force adjusting layer adjacent thereto, the adhesion can be improved as compared with the case where no peeling force adjusting layer is formed. In the 1 st substrate and the 2 nd substrate, the type of the resin film forming the substrate and the type or presence or absence of the peeling force adjusting layer adjacent thereto are appropriately selected and combined in the relationship between the structure and the type of the layer laminated on the substrate (with the peeling force adjusting layer interposed therebetween), whereby the peeling forces F1 and F2 satisfying the above-described expressions (1) to (3) can be easily achieved, and the effects of suppressing the occurrence of the zipper phenomenon and the lifting of the peeling interface at the time of peeling the substrate can be enhanced.

In one embodiment of the present invention, at least one of the peeling force adjusting layers disposed on the 1 st substrate side or the 2 nd substrate side is preferably formed of a layer containing a silane compound or a hard coat layer, more preferably both of the peeling force adjusting layers disposed on the 1 st substrate side and the 2 nd substrate side are formed of a layer containing a silane compound or a hard coat layer, and further preferably at least one of the peeling force adjusting layers disposed on the 1 st substrate side or the 2 nd substrate side is formed of a layer containing a silane compound and a hard coat layer. In the case where the peeling force adjusting layer is formed to include the layer containing the silane compound and the hard coat layer, the structure between the 1 st substrate and the polarizing film or between the 2 nd substrate and the phase difference film is preferably such that the layer containing the silane compound is disposed on the substrate side and the hard coat layer is disposed on the polarizing film or the phase difference film side, and more preferably such that the layer containing the silane compound is adjacent to the hard coat layer. When the peeling force adjusting layer has the above-described configuration, the protective function for the polarizing film and the retardation film is excellent while having a high effect of suppressing the occurrence of a zipper phenomenon and a lift-off at a peeling interface at the time of transfer, and high optical characteristics of the optical laminate can be expected.

In the present invention, when the optical laminate is configured by the 1 st substrate and the 2 nd substrate with the peeling force adjusting layer interposed therebetween, the peeling force adjusting layer disposed on the 1 st substrate side and the peeling force adjusting layer disposed on the 2 nd substrate side are preferably configured to be different from each other.

The peeling force adjusting layers having different structures are different from each other in terms of the composition of the peeling force adjusting layer, the thickness of the peeling force adjusting layer, the combination of the layers when the peeling force adjusting layer is formed of 2 or more layers, the stacking order of the layers, and the like. In particular, when the 1 st substrate and the 2 nd substrate are made of the same resin material, if the peeling force adjusting layer disposed on the 1 st substrate side and the peeling force adjusting layer disposed on the 2 nd substrate side are configured to be different from each other, a sufficient difference is likely to be generated between the peeling force F1 and the peeling force F2, the occurrence of the zipper phenomenon and the lift-off at the peeling interface at the time of transfer can be suppressed, and the 1 st substrate and the 2 nd substrate can be easily peeled from the optical laminate in a desired order. If necessary, the surface of the peeling force adjusting layer on the side on which the alignment film or the like is formed may be subjected to a surface treatment such as corona treatment.

The thickness of the peeling force adjusting layer (the total thickness of all layers in the case of being formed of a plurality of layers) can be appropriately determined depending on the layer configuration of the peeling force adjusting layer, but is preferably 0.1 μm or more, more preferably 0.2 μm or more, further preferably 0.3 μm or more, further preferably 10 μm or less, more preferably 5 μm or less, further preferably 3 μm or less.

[ polarizing film ]

In the present invention, the polarizing film is a film (layer) having a polarizing function, and contains a dichroic dye as a dye having absorption anisotropy. The polarizing film in the optical laminate of the present invention is a coating layer, and is preferably a cured film formed from a polymerizable liquid crystal composition (hereinafter also referred to as a "composition for forming a polarizing film") containing at least 1 liquid crystal compound, preferably a polymerizable liquid crystal compound and a dichroic dye, from the viewpoint of facilitating the reduction in thickness of the optical laminate and ensuring the bending resistance suitable for a flexible display material.

The polymerizable liquid crystal compound (hereinafter also referred to as "polymerizable liquid crystal compound (a)") contained in the polarizing film-forming composition for forming a polarizing film (polarizing plate) of the present invention is a compound having at least 1 polymerizable group. Here, the polymerizable group means a group capable of participating in a polymerization reaction by an active radical, an acid, or the like generated from a polymerization initiator. Examples of the polymerizable group of the polymerizable liquid crystal compound (A) include a vinyl group, a vinyloxy group, a 1-chloroethenyl group, an isopropenyl group, a 4-vinylphenyl group, a (meth) acryloyl group, an epoxyethyl group, and an oxetanyl group. Among these, radical polymerizable groups are preferable, and (meth) acryloyl groups, vinyl groups, and vinyloxy groups are more preferable, and (meth) acryloyl groups are even more preferable. When the polymerizable liquid crystal compound forming the polarizing film has the same functional group (polymerizable group), for example, a (meth) acryloyl group, as the functional group of the compound forming the alignment film for forming the polarizing film described later, the compatibility between the alignment film and the polarizing film is high, and excellent adhesion between layers can be exhibited.

In the present invention, the polymerizable liquid crystal compound (a) is preferably a compound exhibiting smectic liquid crystallinity. By using a polymerizable liquid crystal compound exhibiting smectic liquid crystallinity, a polarizing film having a high degree of orientational order can be formed. From the viewpoint of enabling a higher degree of alignment order to be achieved, the liquid crystal state exhibited by the polymerizable liquid crystal compound (a) is more preferably a higher order smectic phase (higher order smectic liquid crystal state). The higher order smectic phase herein means smectic B phase, smectic D phase, smectic E phase, smectic F phase, smectic G phase, smectic H phase, smectic I phase, smectic J phase, smectic K phase and smectic L phase, and among them, smectic B phase, smectic F phase and smectic I phase are more preferable. The liquid crystal may be a thermotropic liquid crystal or a lyotropic liquid crystal, but the thermotropic liquid crystal is preferable in terms of enabling a dense film thickness control. The polymerizable liquid crystal compound (a) may be a monomer, an oligomer obtained by polymerizing a polymerizable group, or a polymer.

The polymerizable liquid crystal compound (a) is not particularly limited as long as it is a liquid crystal compound having at least 1 polymerizable group, and a known polymerizable liquid crystal compound, preferably a compound exhibiting smectic liquid crystallinity, can be used. Examples of such a polymerizable liquid crystal compound include a compound represented by the following formula (a1) (hereinafter, may be referred to as "polymerizable liquid crystal compound (a 1)").

U1-V1-W1-(X1-Y1)n-X2-W2-V2-Y1 (A1)

[ in the formula (A1),

x1 and X2 each independently represent a 2-valent aromatic group or a 2-valent alicyclic hydrocarbon group, wherein a hydrogen atom contained in the 2-valent aromatic group or the 2-valent alicyclic hydrocarbon group may be substituted with a halogen atom, an alkyl group having 1 to 4 carbon atoms, a fluoroalkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a cyano group, or a nitro group, and a carbon atom forming the 2-valent aromatic group or the 2-valent alicyclic hydrocarbon group may be replaced with an oxygen atom, a sulfur atom, or a nitrogen atom. Wherein at least 1 of X1 and X2 is an optionally substituted 1, 4-phenylene group or an optionally substituted cyclohexane-1, 4-diyl group.

Y1 is a single bond or a divalent linking group.

n is 1 to 3, and when n is 2 or more, a plurality of X1 may be the same or different from each other. X2 may be the same as or different from any or all of X1. When n is 2 or more, Y1 may be the same or different from each other. From the viewpoint of liquid crystallinity, n is preferably 2 or more.

U1 represents a hydrogen atom or a polymerizable group.

U2 represents a polymerizable group.

W1 and W2 are each independently a single bond or a divalent linking group.

V1 and V2 independently represent an alkanediyl group having 1 to 20 carbon atoms which may have a substituent, and-CH forming the alkanediyl group ₂ -may be replaced by-O-, -CO-, -S-or NH-.]

In the polymerizable liquid crystal compound (a1), X1 and X2 are independently preferably a1, 4-phenylene group which may have a substituent or a cyclohexane-1, 4-diyl group which may have a substituent, and at least 1 of X1 and X2 is a1, 4-phenylene group which may have a substituent or a cyclohexane-1, 4-diyl group which may have a substituent, and is preferably a trans-cyclohexane-1, 4-diyl group. Examples of the optionally substituted 1, 4-phenylene group which may have a substituent or the optionally substituted cyclohexane-1, 4-diyl group include an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group and a butyl group, a cyano group, a halogen atom such as a chlorine atom and a fluorine atom. Preferably unsubstituted.

In addition, in the polymerizable liquid crystal compound (a1), from the viewpoint of easily exhibiting smectic liquid crystallinity, it is preferable that in the formula (a1), the portion [ hereinafter also referred to as partial structure (a1-1) ] represented by the formula (a1-1) is asymmetric:

-(X1-Y1)n-X2- (A1-1)

in the formula, X1, Y1, X2 and n each have the same meaning as described above. Angle (c)

Examples of the polymerizable liquid crystal compound (a1) having an asymmetric partial structure (a1-1) include a polymerizable liquid crystal compound (a1) in which n is 1, and 1X 1 and X2 are different structures from each other. Further, there can be mentioned a polymerizable liquid crystal compound (a1) in which n is 2, 2Y 1 are the same structure, 2X 1 are the same structure, and 1X 2 is a structure different from the 2X 1; a polymerizable liquid crystal compound (a1) in which X1 bonded to W1 out of 2X 1 has a structure different from that of the other of X1 and X2, and X1 and X2 have the same structure. Further, there can be mentioned a polymerizable liquid crystal compound (a1) in which n is 3, 3Y 1 are the same structure, and 1 of 3X 1 and 1X 2 is any structure different from all of the other 3.

Y1 is preferably-CH ₂ CH ₂ -、-CH ₂ O-、-CH ₂ CH ₂ O-, -COO-, -OCOO-, a single bond, -N ═ N-, -CRa ═ CRb-, -C ≡ C-, -CRa ═ N-, or-CO-NRa-. Ra and Rb are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Y1 is more preferably-CH ₂ CH ₂ -, -COO-or a single bond, and in the case where a plurality of Y1 are present, Y1 bonded to X2 is more preferably-CH ₂ CH ₂ -or CH ₂ O-is added. When X1 and X2 are both of the same structure, it is preferable that 2 or more Y1 having different bonding systems are present. When there are a plurality of Y1 that belong to different bonding systems, the structure tends to be asymmetric, and smectic liquid crystallinity tends to be easily exhibited.

U2 is a polymerizable group. U1 is a hydrogen atom or a polymerizable group, and is preferably a polymerizable group. U1 and U2 are preferably both polymerizable groups, and are preferably both radical polymerizable groups. Examples of the polymerizable group include the same groups as those exemplified above as the polymerizable group of the polymerizable liquid crystal compound (a). The polymerizable group represented by U1 and the polymerizable group represented by U2 may be different from each other, but are preferably the same type of group, and at least one of U1 and U2 is preferably a (meth) acryloyl group, and more preferably both are (meth) acryloyl groups. The polymerizable group may be in a polymerized state or an unpolymerized state, but is preferably in an unpolymerized state.

Examples of the alkanediyl group represented by V1 and V2 include a methylene group, an ethylene group, a propane-1, 3-diyl group, a butane-1, 4-diyl group, a pentane-1, 5-diyl group, a hexane-1, 6-diyl group, a heptane-1, 7-diyl group, an octane-1, 8-diyl group, a decane-1, 10-diyl group, a tetradecane-1, 14-diyl group, and an eicosane-1, 20-diyl group. V1 and V2 are preferably alkanediyl having 2 to 12 carbon atoms, and more preferably alkanediyl having 6 to 12 carbon atoms.

Examples of the substituent optionally contained in the alkanediyl group include a cyano group and a halogen atom, and the alkanediyl group is preferably an unsubstituted, more preferably an unsubstituted, linear alkanediyl group.

W1 and W2 are each independently preferably a single bond, -O-, -S-, -COO-or-OCOO-, more preferably a single bond or-O-.

The polymerizable liquid crystal compound (a) is not particularly limited as long as it is a polymerizable liquid crystal compound having at least 1 polymerizable group, and a known polymerizable liquid crystal compound can be used, and preferably a polymerizable liquid crystal compound exhibiting smectic liquid crystallinity, and as a structure which easily exhibits smectic liquid crystallinity, a polymerizable liquid crystal compound having an asymmetric molecular structure in the molecular structure is preferable, and specifically, a polymerizable liquid crystal compound having partial structures of the following (a-a) to (a-i) and exhibiting smectic liquid crystallinity is more preferable. From the viewpoint of easily exhibiting higher order smectic liquid crystallinity, a partial structure having (A-a), (A-b) or (A-c) is more preferable. In the following (a-a) to (a-i), one represents a bonding end (single bond).

[ solution 1]

Specific examples of the polymerizable liquid crystal compound (A) include compounds represented by the formulae (A-1) to (A-25). When the polymerizable liquid crystal compound (a) has a cyclohexane-1, 4-diyl group, the cyclohexane-1, 4-diyl group is preferably a trans-isomer.

[ solution 2]

[ solution 3]

[ solution 4]

Among them, at least 1 kind selected from the compounds represented by the formula (A-2), the formula (A-3), the formula (A-4), the formula (A-5), the formula (A-6), the formula (A-7), the formula (A-8), the formula (A-13), the formula (A-14), the formula (A-15), the formula (A-16) and the formula (A-17) is preferable. The polymerizable liquid crystal compound (a) may be used alone in 1 kind, or may be used in combination in 2 or more kinds.

The polymerizable liquid crystal compound (A) can be produced by a known method described in Lub et al, Recl. Trav. Chim. Pays-Bas, 115, 321-328(1996), Japanese patent No. 4719156, and the like.

In the present invention, the composition for forming a polarizing film may contain other polymerizable liquid crystal compounds than the polymerizable liquid crystal compound (a), but from the viewpoint of obtaining a polarizing film having a high degree of alignment order, the proportion of the polymerizable liquid crystal compound (a) to the total mass of all the polymerizable liquid crystal compounds contained in the composition for forming a polarizing film is preferably 51 mass% or more, more preferably 70 mass% or more, and still more preferably 90 mass% or more.

When the polarizing film-forming composition contains 2 or more polymerizable liquid crystal compounds (a), at least 1 of them may be the polymerizable liquid crystal compound (a1), or all of them may be the polymerizable liquid crystal compound (a 1). By combining a plurality of polymerizable liquid crystal compounds, the liquid crystal properties can be temporarily maintained even at a temperature not higher than the liquid crystal-to-crystal phase transition temperature.

The content of the polymerizable liquid crystal compound in the composition for forming a polarizing film is preferably 40 to 99.9% by mass, more preferably 60 to 99% by mass, and still more preferably 70 to 99% by mass, based on the solid content of the composition for forming a polarizing film. When the content of the polymerizable liquid crystal compound is within the above range, the orientation of the polymerizable liquid crystal compound tends to be high.

In the present invention, the composition for forming a polarizing film contains a dichroic dye. Here, the dichroic dye is a dye having a property that the absorbance of a molecule in the major axis direction is different from the absorbance of a molecule in the minor axis direction. The dichroic dye that can be used in the present invention is not particularly limited as long as it has the above-described properties, and may be a dye or a pigment. In addition, 2 or more kinds of dyes or pigments may be used in combination, or a dye and a pigment may be used in combination. The dichroic dye may have polymerizability or liquid crystal properties.

The dichroic dye is preferably a dichroic dye having a maximum absorption wavelength (λ MAX) in the range of 300 to 700 nm. Examples of such dichroic dyes include acridine dyes, oxazine dyes, cyanine dyes, naphthalene dyes, azo dyes, and anthraquinone dyes.

Examples of the azo dye include monoazo dyes, disazo dyes, trisazo dyes, tetrazo dyes, and stilbene azo dyes, and the disazo dyes and the trisazo dyes are preferable, and for example, a compound represented by formula (I) (hereinafter also referred to as "compound (I)") can be exemplified.

K1(-N＝N-K2)p-N＝N-K3 (I)

[ in the formula (I), K1 and K3 each independently represent an optionally substituted phenyl group, an optionally substituted naphthyl group, an optionally substituted phenylbenzoate group, or an optionally substituted 1-valent heterocyclic group. K2 represents a p-phenylene group which may have a substituent, a naphthalene-1, 4-diyl group which may have a substituent, a4, 4' -stilbenylene group which may have a substituent (Japanese: スチルベ -diyl レン group), or a 2-valent heterocyclic group which may have a substituent. p represents an integer of 0 to 4. When p is an integer of 2 or more, K2 s may be the same or different from each other. The — N ═ N-bond may be replaced by — C ═ C-, -COO-, -NHCO-, -N ═ CH-bond in the range showing absorption in the visible region. ]

Examples of the heterocyclic group having a valence of 1 include groups obtained by removing 1 hydrogen atom from a heterocyclic compound such as quinoline, thiazole, benzothiazole, thienothiazole, imidazole, benzimidazole, oxazole and benzoxazole. The heterocyclic group having a valence of 2 includes a group obtained by removing 2 hydrogen atoms from the above-mentioned heterocyclic compound.

Examples of the optional substituents of the phenyl group, naphthyl group, benzoate group and 1-valent heterocyclic group in K1 and K3, and the p-phenylene group, naphthalene-1, 4-diyl group, 4' -stilbenylene group and 2-valent heterocyclic group in K2 include an alkyl group having 1 to 20 carbon atoms, an alkyl group having 1 to 20 carbon atoms and an alkenyl group having 1 to 4 carbon atoms, each of which has a polymerizable group; alkoxy groups having 1 to 20 carbon atoms such as methoxy, ethoxy, butoxy and the like; an alkoxy group having 1 to 20 carbon atoms and having a polymerizable group; a C1-4 fluoroalkyl group such as a trifluoromethyl group; a cyano group; a nitro group; a halogen atom; and substituted or unsubstituted amino groups such as amino group, diethylamino group, and pyrrolidinyl group (the substituted amino group means an amino group having 1or 2 alkyl groups having 1 to 6 carbon atoms, an amino group having 1or 2 alkyl groups having 1 to 6 carbon atoms and a polymerizable group, or an amino group in which 2 substituted alkyl groups are bonded to each other to form an alkanediyl group having 2 to 8 carbon atoms, and the unsubstituted amino group is — NH 2). Examples of the polymerizable group include a (meth) acryloyl group, a (meth) acryloyloxy group, and the like.

Among the compounds (I), the compounds represented by any of the following formulae (I-1) to (I-8) are also preferable.

[ solution 5]

[ formulae (I-1) to (I-8),

B ¹ ～B ³⁰ independent earth surfaceA hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a cyano group, a nitro group, a substituted or unsubstituted amino group (the definitions of the substituted amino group and the unsubstituted amino group are as described above), a chlorine atom or a trifluoromethyl group.

n1 to n4 each independently represents an integer of 0 to 3.

When n1 is 2 or more, a plurality of B ² May be the same as, or different from,

when n2 is 2 or more, a plurality of B ⁶ May be the same as, or different from,

when n3 is 2 or more, a plurality of B ⁹ May be the same as, or different from,

when n4 is 2 or more, a plurality of B ¹⁴ May be the same as or different from each other.]

As the anthraquinone dye, a compound represented by the formula (I-9) is preferable.

[ solution 6]

[ in the formula (I-9),

R ¹ ～R ⁸ independently of each other, represents a hydrogen atom, -Rx, -NH ₂ 、-NHRx、-NRx ₂ -SRx or a halogen atom.

Rx represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 12 carbon atoms. ]

As the oxazinone (oxazone) pigment, a compound represented by the formula (I-10) is preferred.

[ solution 7]

[ in the formula (I-8),

R ⁹ ～R ¹⁵ independently of each other, represents a hydrogen atom, -Rx, -NH ₂ 、-NHRx、-NRx ₂ -SRx or a halogen atom.

As the acridine pigment, a compound represented by the formula (I-11) is preferable.

[ solution 8]

[ in the formula (I-11),

R ¹⁶ ～R ²³ independently of each other, represents a hydrogen atom, -Rx, -NH ₂ 、-NHRx、-NRx ₂ -SRx or a halogen atom.

In the formulae (I-9), (I-10) and (I-11), Rx is an alkyl group having 1 to 6 carbon atoms such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group and a hexyl group, and Rx is an aryl group having 6 to 12 carbon atoms such as a phenyl group, a tolyl group, a xylyl group and a naphthyl group.

As the cyanine dye, a compound represented by the formula (I-12) and a compound represented by the formula (I-13) are preferable.

[ solution 9]

[ in the formula (I-12),

D ¹ and D ² Independently of each other, represents a group represented by any one of the formulae (I-12a) to (I-12 d).

[ solution 10]

n5 represents an integer of 1 to 3. ]

[ solution 11]

[ in the formula (I-13),

D ³ and D ⁴ Independently represent a group represented by any one of the formulae (I-13a) to (1-13 h).

[ solution 12]

n6 represents an integer of 1 to 3. ]

Among these dichroic dyes, azo dyes are suitable for producing polarizing films having excellent polarizing properties because of their high linearity. Therefore, in one embodiment of the present invention, the dichroic dye contained in the polarizing film-forming composition forming the polarizing film is preferably an azo dye.

In the present invention, the weight average molecular weight of the dichroic dye is usually 300 to 2000, preferably 400 to 1000.

In one embodiment of the present invention, the dichroic dye contained in the polarizing film-forming composition forming the polarizing film is preferably hydrophobic. When the dichroic dye is hydrophobic, the compatibility between the dichroic dye and the polymerizable liquid crystal compound is improved, the dichroic dye and the polymerizable liquid crystal compound form a uniform phase state, and a polarizing film having a high degree of alignment order can be obtained. In the present invention, the hydrophobic dichroic dye means a dye having a solubility of 1g or less with respect to 100g of water at 25 ℃.

The content of the dichroic dye in the composition for forming a polarizing film may be appropriately determined depending on the kind of the dichroic dye used, and is preferably 0.1 to 50 parts by mass, more preferably 0.1 to 20 parts by mass, and still more preferably 0.1 to 12 parts by mass, based on 100 parts by mass of the polymerizable liquid crystal compound. When the content of the dichroic dye is within the above range, the orientation of the polymerizable liquid crystal compound is less likely to be disturbed, and a polarizing film having a high degree of orientation order can be obtained.

In the present invention, the composition for forming a polarizing film may contain a polymerization initiator. The polymerization initiator is a compound capable of initiating a polymerization reaction of the polymerizable liquid crystal compound, and is preferably a photopolymerization initiator in terms of being capable of initiating a polymerization reaction under a lower temperature condition. Specifically, there may be mentioned photopolymerization initiators capable of generating active radicals or acids by the action of light, and among them, photopolymerization initiators capable of generating radicals by the action of light are preferred. The polymerization initiator may be used alone or in combination of two or more.

As the photopolymerization initiator, a known photopolymerization initiator can be used, and examples of the photopolymerization initiator generating active radicals include a self-cleavage type photopolymerization initiator and a hydrogen abstraction type photopolymerization initiator.

As the self-cleavage type photopolymerization initiator, a self-cleavage type benzoin-based compound, an acetophenone-based compound, a hydroxyacetophenone-based compound, an α -aminoacetophenone-based compound, an oxime ester-based compound, an acylphosphine oxide-based compound, an azo-based compound, or the like can be used. Further, as the hydrogen abstraction type photopolymerization initiator, a hydrogen abstraction type benzophenone-based compound, benzoin ether-based compound, benzil ketal-based compound, dibenzosuberone-based compound, anthraquinone-based compound, xanthenone-based compound, thioxanthone-based compound, halogenated acetophenone-based compound, dialkoxyacetophenone-based compound, halogenated bisimidazole-based compound, halogenated triazine-based compound, and the like can be used.

As the photopolymerization initiator generating an acid, iodonium salts, sulfonium salts, and the like can be used.

Among them, from the viewpoint of preventing the dissolution of the dye, a reaction at a low temperature is preferable, and from the viewpoint of reaction efficiency at a low temperature, a self-cleavage type photopolymerization initiator is preferable, and particularly, an acetophenone-based compound, a hydroxyacetophenone-based compound, an α -aminoacetophenone-based compound, and an oxime ester-based compound are preferable.

Specific examples of the photopolymerization initiator include the following photopolymerization initiators.

Benzoin-based compounds such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin isobutyl ether;

hydroxyacetophenone-based compounds such as oligomers of 2-hydroxy-2-methyl-1-phenyl-1-propanone, 1, 2-diphenyl-2, 2-dimethoxy-1-ethanone, 2-hydroxy-2-methyl-1- [4- (2-hydroxyethoxy) phenyl ] -1-propanone, 1-hydroxycyclohexyl phenyl ketone and 2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl ] -1-propanone;

α -aminoacetophenone-based compounds such as 2-methyl-2-morpholinophenyl-1- (4-methylthiophenyl) -1-propanone and 2-dimethylamino-2-benzyl-1- (4-morpholinophenyl) -1-butanone;

oxime ester compounds such as 1- [4- (phenylthio) ]1, 2-octanedione 2- (O-benzoyloxime) and 1- [ 9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl ] ethanone 1- (O-acetyloxime); acylphosphine oxide-based compounds such as 2, 4, 6-trimethylbenzoyldiphenylphosphine oxide and bis (2, 4, 6-trimethylbenzoyl) phenylphosphine oxide;

benzophenone compounds such as benzophenone, methyl benzoylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4 ' -methyldiphenyl sulfide, 3 ', 4, 4 ' -tetrakis (t-butylperoxycarbonyl) benzophenone, and 2, 4, 6-trimethylbenzophenone;

dialkoxyacetophenone-based compounds such as diethoxyacetophenone;

2, 4-bis (trichloromethyl) -6- (4-methoxyphenyl) -1, 3, 5-triazine, 2, 4-bis (trichloromethyl) -6- (4-methoxynaphthyl) -1, 3, 5-triazine, 2, 4-bis (trichloromethyl) -6- (4-methoxystyryl) -1, 3, 5-triazine, 2, 4-bis (trichloromethyl) -6- [ 2- (5-methylfuran-2-yl) vinyl ] -1, 3, 5-triazine, 2, 4-bis (trichloromethyl) -6- [ 2- (furan-2-yl) vinyl ] -1, 3, 5-triazine Triazine compounds such as (E) -2-methylphenyl) vinyl ] -1, 3, 5-triazine and (E) -2, 4-bis (trichloromethyl) -6- [ 2- (3, 4-dimethoxyphenyl) vinyl ] -1, 3, 5-triazine. The photopolymerization initiator may be appropriately selected from the above photopolymerization initiators in relation to the polymerizable liquid crystal compound contained in the polarizing film-forming composition, for example.

Further, a commercially available photopolymerization initiator may be used. Examples of commercially available polymerization initiators include Irgacure (registered trademark) 907, 184, 651, 819, 250, 369, 379, 127, 754, OXE01, OXE02, OXE03 (manufactured by BASF); omnirad BCIM, Escapure 1001M, Escapure KIP160 (manufactured by IDM Resins B.V.); seikuol (registered trademark) BZ, Z and BEE (manufactured by Seiko chemical Co., Ltd.); kayacure (registered trademark) BP100, and UVI-6992 (manufactured by Dow Chemical corporation); adeka Optomer SP-152, N-1717, N-1919, SP-170, Adeka Arkls NCI-831, Adeka Arkls NCI-930 (manufactured by ADEKA Co., Ltd.); TAZ-A and TAZ-PP (manufactured by Siber Hegner, Japan); and TAZ-104 (manufactured by Kabushiki Kaisha and Chemicals); and the like.

The content of the polymerization initiator in the composition for forming a polarizing film is preferably 1 to 10 parts by mass, more preferably 1 to 8 parts by mass, even more preferably 2 to 8 parts by mass, and particularly preferably 4 to 8 parts by mass, based on 100 parts by mass of the polymerizable liquid crystal compound. When the content of the polymerization initiator is within the above range, the polymerization reaction of the polymerizable liquid crystal compound can proceed without largely disturbing the orientation of the polymerizable liquid crystal compound.

The polymerization rate of the polymerizable liquid crystal compound in the present invention is preferably 60% or more, more preferably 65% or more, and even more preferably 70% or more, from the viewpoint of line contamination and disposal at the time of production.

The composition for forming a polarizing film may further contain a photosensitizer. By using the photosensitizer, the polymerization reaction of the polymerizable liquid crystal compound can be further promoted. Examples of the photosensitizer include xanthone compounds such as xanthone and thioxanthone (for example, 2, 4-diethylthioxanthone and 2-isopropylthioxanthone); anthracene compounds such as anthracene and alkoxy-containing anthracene (e.g., dibutoxyanthracene); phenothiazine, rubrene, and the like. The photosensitizers may be used singly or in combination of 2 or more.

When the composition for forming a polarizing film contains a photosensitizer, the content thereof may be determined appropriately according to the kind and amount of the polymerization initiator and the polymerizable liquid crystal compound, and is preferably 0.1 to 30 parts by mass, more preferably 0.5 to 10 parts by mass, and still more preferably 0.5 to 8 parts by mass, relative to 100 parts by mass of the polymerizable liquid crystal compound.

In addition, the polarizing film-forming composition may contain a leveling agent. The leveling agent has a function of adjusting the fluidity of the composition for forming a polarizing film and flattening a coating film obtained by applying the composition for forming a polarizing film, and specifically includes a surfactant. The leveling agent is preferably at least 1 selected from leveling agents containing a polyacrylate compound as a main component and leveling agents containing a fluorine atom-containing compound as a main component. The leveling agent may be used alone or in combination of 2 or more.

Examples of the leveling agent containing a polyacrylate compound as a main component include "BYK-350", "BYK-352", "BYK-353", "BYK-354", "BYK-355", "BYK-358N", "BYK-361N", "BYK-380", "BYK-381", and "BYK-392" (BYK Chemie).

Examples of the leveling agent containing a fluorine atom-containing compound as a main component include "Megafac (registered trademark) R-08", "Megafac R-30", "Megafac R-90", "Megafac F-410", "Megafac F-411", "Megafac F-443", "Megafac F-445", "Megafac F-470", "Megafac F-471", "Megafac F-477", "Megafac F-479", "Megafac F-482" and "Megafac F-483" (available from DIC corporation)); "Surflon (registered trademark) S-381", "Surflon S-382", "Surflon S-383", "Surflon S-393", "Surflon SC-101", "Surflon SC-105", "KH-40" and "SA-100" (AGC SEIMI CHEMICAL (strain)); "E1830", "E5844" (strain) DAIKIN FINE CHEMICAL institute); "Eftop EF 301", "Eftop EF 303", "Eftop EF 351" and "Eftop EF 352" (Mitsubishi Material electronics Kabushiki Kaisha).

When the composition for forming a polarizing film contains a leveling agent, the content thereof is preferably 0.05 to 5 parts by mass, and more preferably 0.05 to 3 parts by mass, based on 100 parts by mass of the polymerizable liquid crystal compound. When the content of the leveling agent is within the above range, the polymerizable liquid crystal compound is easily aligned, and unevenness is less likely to occur, and a smoother polarizing film tends to be obtained.

The composition for forming a polarizing film may contain other additives besides the photosensitizer and the leveling agent. Examples of the other additives include colorants such as antioxidants, mold release agents, stabilizers, and bluing agents, flame retardants, and lubricants. When the composition for forming a polarizing film contains other additives, the content of the other additives is preferably more than 0% and 20% by mass, more preferably more than 0% and 10% by mass, based on the solid content of the composition for forming a polarizing film.

The composition for forming a polarizing film can be produced by a conventionally known method for producing a composition for forming a polarizing film, and can be usually produced by mixing and stirring a polymerizable liquid crystal compound, a dichroic dye, a polymerization initiator used as needed, the above-mentioned additives, and the like. In addition, since the compound exhibiting smectic liquid crystallinity has a high viscosity, the viscosity can be adjusted by adding a solvent to the composition for forming a polarizing film, in order to improve the coatability of the composition for forming a polarizing film and facilitate the formation of the polarizing film.

The solvent used in the composition for forming a polarizing film may be appropriately selected depending on the solubility of the polymerizable liquid crystal compound and the dichroic dye used. Specifically, the same solvent as that used in the solution containing the silane compound as in the above-described examples can be used. The solvent may be used alone in 1 kind, or may be used in combination of 2 or more kinds. The content of the solvent is preferably 100 to 1900 parts by mass, more preferably 150 to 900 parts by mass, and still more preferably 180 to 600 parts by mass, per 100 parts by mass of the solid content of the composition for forming a polarizing film.

In the present invention, the polarizing film is preferably a polarizing plate having a high degree of orientation order. The polarizing plate having a high degree of orientation order can obtain a bragg peak derived from a high-order structure such as a hexagonal phase or a crystal phase in X-ray diffraction measurement. The bragg peak is a peak derived from a plane periodic structure of molecular orientation. Therefore, the polarizing film forming the optical laminate of the present invention preferably exhibits bragg peaks in X-ray diffraction measurement. That is, in the polarizing film forming the optical laminate of the present invention, it is preferable to orient the polymerizable liquid crystal compound or the polymer thereof so that the polarizing film exhibits a bragg peak in X-ray diffraction measurement, and it is more preferable to perform "horizontal orientation" in which the molecules of the polymerizable liquid crystal compound are oriented in the direction of absorbing light. In the present invention, a polarizing plate having a circumferential period interval of 3.0 to 6.0 apertures in molecular orientation is preferable. The high degree of alignment order of the bragg peak can be achieved by controlling the kind of the polymerizable liquid crystal compound used, the kind and amount of the dichroic dye, and the kind and amount of the polymerization initiator.

The polarizing film of the present invention can be obtained, for example, by a method comprising forming a coating film of the composition for forming a polarizing film on an alignment film described later; removing the solvent from the coating film; raising the temperature to a temperature not lower than the temperature at which the polymerizable liquid crystal compound changes into a liquid phase, and then lowering the temperature to change the polymerizable liquid crystal compound into a liquid crystal phase (smectic phase); and polymerizing the polymerizable liquid crystal compound while maintaining the liquid crystal phase.

The method of applying the composition for forming a polarizing film to an alignment film may be the same as the method of applying a solution containing a silane compound to a substrate.

Then, the solvent is removed by drying or the like under the condition that the polymerizable liquid crystal compound contained in the coating film obtained from the composition for forming a polarizing film is not polymerized, thereby forming a dried coating film. Examples of the drying method include natural drying, air drying, heat drying, and reduced-pressure drying.

In order to change the polymerizable liquid crystal compound phase to a liquid phase, the temperature is raised to a temperature equal to or higher than the temperature at which the polymerizable liquid crystal compound phase changes to a liquid phase, and then the temperature is lowered to change the polymerizable liquid crystal compound phase to a liquid crystal phase (smectic phase). The phase transition may be performed after the solvent in the coating film is removed, or may be performed simultaneously with the removal of the solvent.

The polymerizable liquid crystal compound is polymerized while maintaining the liquid crystal state of the polymerizable liquid crystal compound, whereby a polarizing film can be formed as a cured product of the polarizing film-forming composition. The polymerization method is preferably a photopolymerization method. In photopolymerization, the light to be irradiated to the dried coating film can be appropriately selected depending on the type of the polymerizable liquid crystal compound contained in the dried coating film (particularly, the type of the polymerizable group contained in the polymerizable liquid crystal compound), the type of the polymerization initiator, the amount of the polymerization initiator, and the like. Specific examples thereof, irradiation conditions, and the like include those similar to those exemplified in the formation of the hard coat layer. It is preferable to select the types of the polymerizable liquid crystal compound and the polymerization initiator contained in the composition for forming a polarizing film so as to be photopolymerizable by ultraviolet light. In addition, the polymerization temperature may be controlled by irradiating light while cooling the dried coating film by an appropriate cooling mechanism at the time of polymerization. The polarizing film subjected to the pattern treatment may also be obtained by performing masking, development, or the like at the time of photopolymerization.

By performing photopolymerization, the polymerizable liquid crystal compound is polymerized while maintaining a liquid crystal state of a liquid crystal phase, particularly a smectic phase, preferably a higher order smectic phase, to form a polarizing film. A polarizing film obtained by polymerizing a polymerizable liquid crystal compound while maintaining a liquid crystal state of a smectic phase is advantageous in that it has a higher polarizing performance than a conventional host-guest polarizing film, that is, a polarizing film formed in a liquid crystal state of a nematic phase, due to the action of the dichroic dye. Further, the polarizing film has an advantage of being excellent in strength as compared with a polarizing film coated with only a dichroic dye or a lyotropic liquid crystal.

The thickness of the polarizing film is suitably selected depending on the display device to be used, and is preferably 0.1 to 5 μm, more preferably 0.3 to 4 μm, and still more preferably 0.5 to 3 μm. When the film thickness of the polarizing film is equal to or more than the above-described lower limit, it is easy to prevent the failure to obtain necessary light absorption, and when the film thickness is equal to or less than the above-described upper limit, it is easy to suppress the occurrence of alignment defects due to a decrease in the alignment regulating force of the alignment film.

In the present invention, it is preferable that the polarizing film is laminated adjacent to the alignment film laminated on the 1 st substrate with or without the peeling force adjusting layer interposed therebetween. The alignment film has an alignment regulating force for aligning the liquid crystal of the polymerizable liquid crystal compound in a desired direction, and by applying the composition for forming a polarizing film to the alignment film, a polarizing film having an excellent alignment precision can be easily obtained. The alignment film is preferably one having solvent resistance that does not dissolve due to application of the composition for forming a polarizing film, and heat resistance for use in heat treatment for removing the solvent and aligning the polymerizable liquid crystal compound. In the present invention, the alignment film is preferably a photo-alignment film from the viewpoints of accuracy and quality of an alignment angle, and water resistance and bending resistance of an optical laminate including the alignment film. The photo alignment film can arbitrarily control the direction of the alignment regulating force by selecting the polarization direction of the irradiated polarized light, and is also advantageous from this point of view.

The photo alignment film can be generally obtained by applying a composition containing a polymer, oligomer, or monomer having a photoreactive group (hereinafter, also referred to as "polymer having a photoreactive group, or the like") and a solvent (hereinafter, also referred to as "composition for forming a photo alignment film") to a substrate and irradiating the substrate with polarized light (preferably polarized UV). In the optical layered body of the present invention, the composition for forming a photo-alignment film may be applied to the 1 st base material on which the peeling force adjusting layer is laminated as necessary, and when the peeling force adjusting layer is laminated on the 1 st base material, the composition for forming a photo-alignment film is applied to the peeling force adjusting layer. When the polymer or the like contained in the composition for forming a photo-alignment film has the same reactive group (for example, a (meth) acryloyl group) as the polymerizable group of the polymerizable liquid crystal compound forming the polarizing film and the functional group of the compound forming the peeling force adjusting layer, the adhesion between the peeling force adjusting layer and the photo-alignment film and the polarizing film tends to be improved, and the peeling force F1 effective for suppressing the generation of the zipper phenomenon and the generation of the lift-off at the peeling interface at the peeling of the 1 st substrate is easily adjusted.

The photoreactive group refers to a group that can develop liquid crystal alignment ability by light irradiation. Specifically, there may be mentioned groups which participate in photoreaction originating from liquid crystal aligning ability, such as orientation induction or isomerization reaction of molecules by light irradiation, dimerization reaction, photocrosslinking reaction, or photolysis reaction. Among them, a group participating in dimerization reaction or photocrosslinking reaction is preferable from the viewpoint of excellent orientation. As the photoreactive group, a group having an unsaturated bond, particularly a double bond is preferable, and a group having at least 1 kind selected from a carbon-carbon double bond (C ═ C bond), a carbon-nitrogen double bond (C ═ N bond), a nitrogen-nitrogen double bond (N ═ N bond), and a carbon-oxygen double bond (C ═ O bond) is particularly preferable.

Examples of the photoreactive group having a C ═ C bond include a vinyl group, a polyene group, a stilbene onium group, a chalcone group, and a cinnamoyl group. Examples of the photoreactive group having a C ═ N bond include groups having a structure such as an aromatic schiff base and an aromatic hydrazone. Examples of the photoreactive group having an N ═ N bond include an azophenyl group, an azonaphthyl group, an aromatic heterocyclic azo group, a bisazo group, a formazan group, and a group having an azoxybenzene structure. Examples of the photoreactive group having a C ═ O bond include a benzophenone group, a coumarin group, an anthraquinone group, and a maleimide group. These groups may have substituents such as alkyl groups, alkoxy groups, aryl groups, allyloxy groups, cyano groups, alkoxycarbonyl groups, hydroxyl groups, sulfonic acid groups, and halogenated alkyl groups.

Among them, a photoreactive group participating in a photodimerization reaction is preferable, and cinnamoyl group and chalcone group are preferable in terms of a relatively small amount of polarized light irradiation necessary for photo-alignment, easy obtainment of a photo-alignment film having excellent thermal stability and temporal stability. As the polymer having a photoreactive group, a polymer having a cinnamoyl group in which a terminal portion of a polymer side chain is a cinnamic acid structure is particularly preferable.

The photo-alignment layer can be formed by applying the composition for forming a photo-alignment film, for example, to a protective layer laminated on the first film. The solvent contained in the composition may be the same solvent as the solvent exemplified above as a solvent that can be used for forming a polarizing film, and may be appropriately selected depending on the solubility of the polymer having a photoreactive group or the like.

The content of the polymer having a photoreactive group or the like in the composition for forming a photoalignment film may be appropriately adjusted according to the kind of the polymer or the like and the thickness of the target photoalignment film, but is preferably at least 0.2 mass%, and more preferably in the range of 0.3 to 10 mass% with respect to the mass of the composition for forming a photoalignment film. The composition for forming a photo-alignment film may include a polymer material such as polyvinyl alcohol or polyimide, and a photosensitizer in a range that does not significantly impair the characteristics of the photo-alignment film.

Examples of the method of applying the composition for forming a photoalignment film to a substrate or a peeling force adjusting layer and the method of removing a solvent from the applied composition for forming a photoalignment film include the same methods as the method of applying a solution containing a silane compound to a substrate and the method of removing a solvent.

The irradiation with polarized light may be performed by directly irradiating the coating film of the photo alignment film-forming composition with polarized UV after removing the solvent therefrom, or may be performed by irradiating the coating film with polarized light from the substrate side and transmitting the polarized light therethrough. In addition, the polarized light is particularly preferably substantially parallel light. The wavelength of the irradiated polarized light may be a wavelength of a wavelength region in which the photoreactive group of the polymer having the photoreactive group or the like can absorb optical energy. Specifically, UV (ultraviolet) light having a wavelength of 250 to 400nm is particularly preferable. Examples of the light source used for the polarized light irradiation include a xenon lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a metal halide lamp, and an ultraviolet laser such as KrF and ArF, and more preferably a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, and a metal halide lamp. Among them, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, and a metal halide lamp are preferable because the emission intensity of ultraviolet rays having a wavelength of 313nm is large. Polarized UV can be irradiated by irradiating light from the light source after passing through an appropriate polarizing plate. As the polarizing plate, a polarizing prism such as a polarizing filter, a glan thomson prism, or a glan taylor prism, or a wire grid type polarizing plate can be used.

In the case of rubbing or polarized light irradiation, a plurality of regions (patterns) having different liquid crystal alignment directions may be formed by masking.

The thickness of the photo-alignment film is preferably 10 to 5000nm, more preferably 10 to 1000nm, and further preferably 30 to 300 nm. When the thickness of the photo-alignment film is within the above range, good adhesion can be exhibited at the interface with the polarizing film, and the orientation restriction force can be exerted, so that the polarizing film can be formed in high orientation order.

[ retardation film ]

The retardation film contained in the optical laminate of the present invention is a coating layer, and is preferably formed from a cured film of a polymerizable liquid crystal composition containing at least 1 polymerizable liquid crystal compound. In an optical laminate having a circularly polarizing function in which a polarizing film and a retardation film are each formed of a liquid crystal cured film, it has been clarified from studies by the present inventors that a liquid crystal layer structure of a polarizing film having excellent alignment order is destroyed by a zipper phenomenon or lift-off of a peeling interface due to transfer, and the circularly polarizing function of the laminate after transfer can be reduced. In the optical laminate of the present invention, when 2 outer layer surfaces appearing after peeling the 1 st base material and the 2 nd base material are transferred to each other and incorporated in a display device, the effects of suppressing the occurrence of a zipper phenomenon and lift-off at a peeling interface at that time are excellent, and therefore, even after incorporation in a display device or the like by double-sided transfer, a high circular polarization function can be expected. The number of the retardation films in the optical layered body of the present invention may be 1, or may include 2 or more.

The circularly polarizing film transfer sheet of the present invention preferably comprises a phase difference film satisfying formula (4)

120nm≤Re(550)≤170nm (4)

In the formula, Re (λ) represents an in-plane retardation value of the retardation film at a wavelength λ nm. Angle (c)

When the in-plane retardation Re (550) of the retardation film is within the range of formula (4), the retardation film functions as an 1/4 wavelength plate, and when an optical laminate (circularly polarizing plate) including the retardation film is applied to an organic EL display device or the like, the effect of improving the front reflection color tone (the effect of suppressing coloring) is easily improved. A more preferable range of the in-plane phase difference value is 130 nm. ltoreq. Re (550). ltoreq.150 nm.

The retardation film preferably satisfies the following formulae (5) and (6).

Re(450)/Re(550)≤1.00 (5)

1.00≤Re(650)/Re(550) (6)

When the retardation film satisfies the expressions (5) and (6), the retardation film exhibits so-called reverse wavelength dispersibility in which the in-plane retardation value at a short wavelength is smaller than the in-plane retardation value at a long wavelength. An optical laminate (circularly polarizing plate) having such a retardation film tends to have an excellent front color tone when incorporated in an organic EL display device or the like. From the viewpoint of enhancing the reverse wavelength dispersibility and further improving the effect of enhancing the reflection color tone in the front direction, Re (450)/Re (550) is preferably 0.70 or more, more preferably 0.78 or more, and further preferably 0.92 or less, more preferably 0.90 or less, further preferably 0.87 or less, particularly preferably 0.86 or less, and further particularly preferably 0.85 or less. Further, Re (650)/Re (550) is preferably 1.01 or more, more preferably 1.02 or more.

The in-plane retardation value can be adjusted by the film thickness dA of the retardation film. Since the in-plane retardation value is determined by the above formula ReA (λ) ═ nxA (λ) -nyA (λ)) × dA, the three-dimensional refractive index and the film thickness dA may be adjusted to obtain a desired in-plane retardation value (ReA (λ): the in-plane retardation value of the retardation film at the wavelength λ (nm)).

The optical laminate of the present invention preferably includes a retardation film formed of a "horizontally aligned liquid crystal cured film" obtained by curing a polymerizable liquid crystal compound in a state of being aligned in a horizontal direction with respect to the plane of the retardation film. When the optical laminate of the present invention includes 1 retardation film, the retardation film is usually a "horizontally aligned liquid crystal cured film".

The optical laminate of the present invention may further include a liquid crystal cured film (retardation film) as a positive C plate in addition to the retardation film having the function of the 1/4 wavelength plate. The liquid crystal cured film as the positive C plate is a "vertically aligned liquid crystal cured film" obtained by curing a polymerizable liquid crystal compound in a state of being aligned in the vertical direction with respect to the plane of the retardation film. When the optical laminate is applied to an organic EL display device or the like, improvement in the color tone of the front reflection and improvement in the color tone of the oblique reflection can be expected in addition to improvement in the color tone of the front reflection by combining the liquid crystal cured film including the retardation film having the function of the 1/4 wavelength plate and the positive C plate.

When the optical laminate of the present invention includes a liquid crystal cured film as the positive C plate, the liquid crystal cured film preferably satisfies formulas (7) to (9).

Rth(450)/Rth(550)≤1.00 (7)

1.00≤Rth(650)/Rth(550) (8)

-100nm≤Rth(550)≤-40nm (9)

In the formula, Rth (λ) represents a phase difference value in a thickness direction of the liquid crystal cured film at a wavelength λ nm, (((nx (λ) + ny (λ))/2-nz) × d (d represents a thickness of the liquid crystal cured film), nx represents a main refractive index at the wavelength λ nm in a direction parallel to a plane of the liquid crystal cured film in a refractive index ellipsoid formed by the liquid crystal cured film, ny represents a refractive index at the wavelength λ nm in a direction parallel to the plane of the liquid crystal cured film and orthogonal to the direction of nx in the refractive index ellipsoid formed by the liquid crystal cured film, and nz represents a refractive index at the wavelength λ nm in a direction perpendicular to the plane of the liquid crystal cured film in the refractive index ellipsoid formed by the liquid crystal cured film. Angle (c)

When the liquid crystal cured film satisfies the formulas (7) and (8), the reduction of the ellipticity can be suppressed on the short wavelength side in the circular polarizing film including the retardation film, and the oblique reflection color tone can be improved. The liquid crystal cured film preferably has a value of Rth (450)/Rth (550) of 0.70 or more, more preferably 0.78 or more, and further preferably 0.92 or less, more preferably 0.90 or less, further preferably 0.87 or less, particularly preferably 0.86 or less, and further particularly preferably 0.85 or less. Further, Rth (650)/Rth (550) is preferably 1.01 or more, more preferably 1.02 or more.

In addition, when the liquid crystal cured film satisfies formula (9), the color tone of the oblique reflection when an optical laminate (circularly polarizing plate) including the liquid crystal cured film is applied to an organic EL display device can be improved. The retardation value Rth (550) in the film thickness direction of the liquid crystal cured film is more preferably-90 nm or more, still more preferably-80 nm or more, and still more preferably-50 nm or less.

In the present invention, the retardation film is formed from a cured film of a polymerizable liquid crystal composition (hereinafter also referred to as "composition for forming a retardation film") containing at least 1 polymerizable liquid crystal compound. The polymerizable liquid crystal compound can be appropriately selected from conventionally known polymerizable liquid crystal compounds in the field of retardation films, depending on the desired optical properties.

The polymerizable liquid crystal compound is a liquid crystal compound having a polymerizable group. Examples of the polymerizable liquid crystal compound generally include a polymerizable liquid crystal compound exhibiting a positive wavelength dispersibility and a polymerizable liquid crystal compound exhibiting a reverse wavelength dispersibility, which are polymers (cured products) obtained by polymerizing the polymerizable liquid crystal compound alone in a state of being aligned in a specific direction. In the present invention, only one kind of polymerizable liquid crystal compound may be used, or two kinds of polymerizable liquid crystal compounds may be used in combination. In the case where the optical laminate includes a retardation film having the function of 1/4 wavelength plates and a retardation film formed of a liquid crystal cured film as a positive C plate, the polymerizable liquid crystal compounds forming these films may be the same as or different from each other. In the optical laminate of the present invention, the retardation film is preferably a cured film of a polymerizable liquid crystal composition containing a polymerizable liquid crystal compound, which exhibits so-called reverse wavelength dispersibility, from the viewpoint of facilitating improvement of optical characteristics as an optical laminate.

The polymerizable group of the polymerizable liquid crystal compound forming the retardation film in the present invention is preferably a photopolymerizable group. The photopolymerizable group is a group which is polymerizable and can participate in a polymerization reaction by a reactive species generated from a photopolymerization initiator, for example, an active radical, an acid, or the like. Examples of the photopolymerizable group include a vinyl group, a vinyloxy group, a 1-chloroethenyl group, an isopropenyl group, a 4-vinylphenyl group, a (meth) acryloyl group, an epoxyethyl group, and an oxetanyl group. Among them, (meth) acryloyl, vinyloxy, epoxyethyl and oxetanyl groups are preferable, and acryloyl is more preferable.

The liquid crystallinity exhibited by the polymerizable liquid crystal compound may be a thermotropic liquid crystal or a lyotropic liquid crystal, but a thermotropic liquid crystal is preferable because a dense film thickness can be controlled. The phase-ordered structure of the thermotropic liquid crystal may be a nematic liquid crystal, a smectic liquid crystal, or a discotic liquid crystal. The polymerizable liquid crystal compounds may be used alone or in combination of two or more.

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

The polymerizable liquid crystal compound exhibiting reverse wavelength dispersibility is preferably a compound having the following characteristics (a) to (D).

(A) Are compounds capable of forming a nematic or smectic phase.

(B) The polymerizable liquid crystal compound has pi electrons in the long axis direction (a).

(C) Has pi electrons in a direction [ crossing direction (b) ] crossing the longitudinal direction (a).

(D) A pi electron density in the major axis direction (a) of the polymerizable liquid crystal compound defined by the following formula (i) where N (pi a) represents the total of pi electrons present in the major axis direction (a), and N (aa) represents the total of molecular weights present in the major axis direction (a):

D(πa)＝N(πa)/N(Aa) (i)

and pi electron density in the crossing direction (b) of the polymerizable liquid crystal compound defined by the following formula (ii) in which N (pi b) represents the total of pi electrons present in the crossing direction (b), N (ab) represents the total of molecular weights present in the crossing direction (b), and N (ab) represents the total of molecular weights present in the crossing direction (b):

D(πb)＝N(πb)/N(Ab) (ii)

in the relationship of formula (iii):

0≤〔D(πa)/D(πb)〕＜1 (iii)

that is, the π electron density in the cross direction (b) is greater than that in the long axis direction (a). As described above, a polymerizable liquid crystal compound having pi electrons in the long axis and the direction intersecting the long axis is generally easy to form a T-shaped structure.

In the above features (a) to (D), the major axis direction (a) and the pi-electron number N are defined as follows.

■ for example, if the compound has a rod-like structure, the longitudinal direction (a) is the longitudinal direction of the rod.

■ the number of pi electrons N (pi a) existing in the major axis direction (a) does not include pi electrons lost by the polymerization reaction.

■ represents the total number of pi electrons and pi electrons conjugated to the pi electrons in the major axis direction (a) among the number of pi electrons N (pi a) present in the major axis direction (a), and includes, for example, the number of pi electrons present in a ring satisfying the Huckel rule present in the major axis direction (a).

■ the number of pi electrons N (pi b) existing in the crossing direction (b) does not include pi electrons lost by the polymerization reaction.

The polymerizable liquid crystal compound satisfying the above-mentioned contents has a mesogenic structure in the long axis direction. The mesomorphic structure represents a liquid crystal phase (nematic phase, smectic phase).

By heating the polymerizable liquid crystal compound satisfying the above (a) to (D) to a phase transition temperature or higher, a nematic phase and a smectic phase can be formed. In the nematic phase or smectic phase in which the polymerizable liquid crystal compound is aligned, the polymerizable liquid crystal compound is usually aligned so that the long axis directions thereof are parallel to each other, and the long axis direction is the alignment direction of the nematic phase or smectic phase. When such a polymerizable liquid crystal compound is formed into a film and polymerized in a nematic phase or smectic phase, a polymer film comprising a polymer polymerized in a state of being aligned in the long axis direction (a) can be formed. The polymer film absorbs ultraviolet rays by pi electrons in a major axis direction (a) and pi electrons in a cross direction (b). Here, the absorption maximum wavelength of ultraviolet light absorbed by pi electrons in the cross direction (b) is λ bmax. λ bmax is typically 300nm to 400 nm. Since the density of pi electrons satisfies the above formula (iii) and the pi electron density in the cross direction (b) is higher than the pi electron density in the long axis direction (a), the polymer film is formed such that the absorption of linearly polarized ultraviolet rays (wavelength λ bmax) having a vibration plane in the cross direction (b) is higher than the absorption of linearly polarized ultraviolet rays (wavelength λ bmax) having a vibration plane in the long axis direction (a). The ratio thereof (ratio of absorbance in the cross direction (b) of the linearly polarized ultraviolet rays to absorbance in the longitudinal direction (a)) is, for example, more than 1.0, preferably 1.2 or more, usually 30 or less, for example 10 or less.

In general, when a polymerizable liquid crystal compound having the above-described characteristics is polymerized in a state of being aligned in one direction, the birefringence of the polymer often exhibits reverse wavelength dispersibility. Specifically, for example, a compound represented by the following formula (X) (hereinafter also referred to as "polymerizable liquid crystal compound (X)") can be mentioned.

[ solution 13]

In the formula (X), Ar represents a divalent group having an aromatic group which may have a substituent. Examples of the aromatic group include those exemplified by (Ar-1) to (Ar-23) described later. In addition, Ar may have 2 or more aromatic groups. The aromatic group may contain at least 1or more of a nitrogen atom, an oxygen atom, and a sulfur atom. When the number of the aromatic groups contained in Ar is 2 or more, 2 or more of the aromatic groups may be bonded to each other with a divalent linking group such as a single bond, -CO-O-, -O-, or the like.

In the formula (X), G ¹ And G ² Each independently represents a divalent aromatic group or a divalent alicyclic hydrocarbon group. The hydrogen atom contained in the divalent aromatic group or divalent alicyclic hydrocarbon group may be a halogen atom, an alkyl group having 1 to 4 carbon atoms, a fluoroalkyl group having 1 to 4 carbon atoms, or a carbon atomThe alkoxy group, cyano group or nitro group having a sub-number of 1 to 4 is substituted, and the carbon atom forming the divalent aromatic group or divalent alicyclic hydrocarbon group may be replaced with an oxygen atom, a sulfur atom or a nitrogen atom.

In the formula (X), L ¹ 、L ² 、B ¹ And B ² Each independently is a single bond or a divalent linking group.

In the formula (X), k and l independently represent an integer of 0 to 3, and satisfy a relationship of 1. ltoreq. k + l. Here, in the case of 2. ltoreq. k + l, B ¹ And B ² 、G ¹ And G ² Each may be the same as or different from each other.

In the formula (X), E ¹ And E ² Each independently represents an alkanediyl group having 1 to 17 carbon atoms, more preferably an alkanediyl group having 4 to 12 carbon atoms. Further, a hydrogen atom contained in an alkanediyl group may be substituted with a halogen atom, and-CH contained in the alkanediyl group ₂ -may be substituted by-O-, -S-, -C (═ O) -.

In the formula (X), P ¹ And P ² Independently of each other, a polymerizable group or a hydrogen atom, and at least 1 is a polymerizable group.

G ¹ And G ² Each independently is preferably a1, 4-benzenediyl group which may be substituted with at least 1 substituent selected from a halogen atom and an alkyl group having 1 to 4 carbon atoms, or a1, 4-cyclohexanediyl group which may be substituted with at least 1 substituent selected from a halogen atom and an alkyl group having 1 to 4 carbon atoms, more preferably a1, 4-benzenediyl group which is substituted with a methyl group, an unsubstituted 1, 4-benzenediyl group, or an unsubstituted 1, 4-trans-cyclohexanediyl group, and particularly preferably an unsubstituted 1, 4-benzenediyl group or an unsubstituted 1, 4-trans-cyclohexanediyl group.

In addition, it is preferable that a plurality of G's are present ¹ And G ² At least 1 of them is a divalent alicyclic hydrocarbon group, and is more preferably bonded to L ¹ Or L ² Bonded G ¹ And G ² At least 1 of them is a divalent alicyclic hydrocarbon group.

L ¹ And L ² Independently preferably a single bond, an alkylene group having 1 to 4 carbon atoms, -O-, -S-, -Ra1ORa2-, -Ra3COORa4-, -Ra5OCORa6-, -Ra7OC ═ OORa8-, -N ═ N-, -CRc ═ CRd-, or-C ≡ C-. Ra1 to Ra8 each independently represents a single bond or an alkylene group having 1 to 4 carbon atoms, and Rc and Rd each represent an alkyl group having 1 to 4 carbon atoms or a hydrogen atom. L is ¹ And L ² Each independently more preferably a single bond, -ORa2-1-, -CH ₂ -、-CH ₂ CH ₂ -, -COORa4-1-, or-OCORa 6-1-. Here, Ra2-1, Ra4-1 and Ra6-1 each independently represent a single bond, -CH ₂ -、-CH ₂ CH ₂ Any of (1) to (d). L is ¹ And L ² Further preferably a single bond, -O-, -CH ₂ CH ₂ -、-COO-、-COOCH ₂ CH ₂ -, or-OCO-.

B ¹ And B ² Independently of each other, a single bond, an alkylene group having 1 to 4 carbon atoms, -O-, -S-, -Ra9ORa10-, -Ra11COORa12-, -Ra13OCORa14-, or-Ra 15 OC-OORa 16-is preferable. Ra9 to Ra16 each independently represents a single bond or an alkylene group having 1 to 4 carbon atoms. B is ¹ And B ² Each independently more preferably a single bond, -ORa10-1-, -CH ₂ -、-CH ₂ CH ₂ -, -COORa12-1-, or-OCORa 14-1-. Here, Ra10-1, Ra12-1 and Ra14-1 each independently represent a single bond, -CH ₂ -、-CH ₂ CH ₂ Any of (1) to (d). B is ¹ And B ² Further preferably a single bond, -O-, -CH ₂ CH ₂ -、-COO-、-COOCH ₂ CH ₂ -, -OCO-, or-OCOCH ₂ CH ₂ -。

From the viewpoint of exhibiting reverse wavelength dispersibility, k and l are preferably in the range of 2 ≦ k + l ≦ 6, preferably k + l ═ 4, more preferably k ═ 2 and l ═ 2. If k is 2 and l is 2, a symmetrical structure is formed, which is preferred.

As P ¹ Or P ² Examples of the polymerizable group include an epoxy group, a vinyl group, a vinyloxy group, a 1-chloroethenyl group, an isopropenyl group, a 4-vinylphenyl group, a (meth) acryloyl group, an epoxyethyl group, and an oxetanyl group. Among them, (meth) acryloyl, vinyl and vinyloxy are preferable, and (meth) acryloyl is more preferable.

Ar preferably has at least 1 selected from an aromatic hydrocarbon ring which may have a substituent, an aromatic heterocyclic ring which may have a substituent, and an electron-withdrawing group. Examples of the aromatic hydrocarbon ring include a benzene ring, a naphthalene ring, and an anthracene ring, and a benzene ring and a naphthalene ring are preferable. Examples of the aromatic heterocyclic ring include a furan ring, a benzofuran ring, a pyrrole ring, an indole ring, a thiophene ring, a benzothiophene ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a triazole ring, a triazine ring, a pyrroline ring, an imidazole ring, a pyrazole ring, a thiazole ring, a benzothiazole ring, a thienothiazole ring, an oxazole ring, a benzoxazole ring, and a phenanthroline ring. Among them, a thiazole ring, a benzothiazole ring, or a benzofuran ring is preferable, and a benzothiazole ring is more preferable. In addition, in the case where Ar contains a nitrogen atom, the nitrogen atom preferably has pi electrons.

In the formula (X), the total number N pi of pi electrons of the group represented by Ar is usually 6 or more, preferably 8 or more, more preferably 10 or more, further preferably 14 or more, and particularly preferably 16 or more. Further, it is preferably 36 or less, more preferably 32 or less, further preferably 26 or less, and particularly preferably 24 or less.

Examples of the aromatic group contained in Ar include the following groups.

[ solution 14]

In the formulae (Ar-1) to (Ar-23), the symbol denotes a linker, Z ⁰ 、Z ¹ And Z ² Each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cyano group, a nitro group, an alkylsulfinyl group having 1 to 12 carbon atoms, an alkylsulfonyl group having 1 to 12 carbon atoms, a carboxyl group, a fluoroalkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alkylthio group having 1 to 12 carbon atoms, an N-alkylamino group having 1 to 12 carbon atoms, an N, N-dialkylamino group having 2 to 12 carbon atoms, an N-alkylsulfamoyl group having 1 to 12 carbon atoms, or an N, N-dialkylsulfamoyl group having 2 to 12 carbon atoms. In addition, Z ⁰ 、Z ¹ And Z ² May contain a polymerizable group.

In the formulae (Ar-1) to (Ar-23), Q ¹ And Q ² Each independently represents-CR 2 ' R3 ' -, -S-, -NH-, -NR2 ' -, -CO-, or-O-, and R2 ' and R3 ' each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

In formulae (Ar-1) to (Ar-23), J ¹ And J ² Each independently represents a carbon atom or a nitrogen atom.

In the formulae (Ar-1) to (Ar-23), Y ¹ 、Y ² And Y ³ Each independently represents an aromatic hydrocarbon group or an aromatic heterocyclic group which may be substituted.

In the formulae (Ar-1) to (Ar-23), W ¹ And W ² Each independently represents a hydrogen atom, a cyano group, a methyl group or a halogen atom, and m represents an integer of 0 to 6.

As Y ¹ 、Y ² And Y ³ The aromatic hydrocarbon group in (3) includes aromatic hydrocarbon groups having 6 to 20 carbon atoms such as a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group, and a biphenyl group, preferably a phenyl group and a naphthyl group, and more preferably a phenyl group. Examples of the aromatic heterocyclic group include an aromatic heterocyclic group having 4 to 20 carbon atoms containing at least 1 hetero atom such as a nitrogen atom, an oxygen atom, a sulfur atom and the like, such as a furyl group, a pyrrolyl group, a thienyl group, a pyridyl group, a thiazolyl group, a benzothiazolyl group and the like, and preferably a furyl group, a thienyl group, a pyridyl group, a thiazolyl group and a benzothiazolyl group.

Y ¹ 、Y ² And Y ³ Each of which may be independently a polycyclic aromatic hydrocarbon group or a polycyclic aromatic heterocyclic group which may be substituted. The polycyclic aromatic hydrocarbon group means a fused polycyclic aromatic hydrocarbon group or a group derived from an aromatic ring assembly. The polycyclic aromatic heterocyclic group means a fused polycyclic aromatic heterocyclic group or a group derived from an aromatic ring assembly.

Z ⁰ 、Z ¹ And Z ² Each independently preferably represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cyano group, a nitro group, an alkoxy group having 1 to 12 carbon atoms, Z ⁰ More preferably a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or a cyano group，Z ¹ And Z ² More preferably a hydrogen atom, fluorine atom, chlorine atom, methyl group or cyano group. In addition, Z ⁰ 、Z ¹ And Z ² May contain a polymerizable group.

Q ¹ And Q ² preferably-NH-, -S-, -NR2 '-, -O-, and R2' is preferably a hydrogen atom. Among them, particularly preferred are-S-, -O-, -NH-.

Among the formulae (Ar-1) to (Ar-23), the formulae (Ar-6) and (Ar-7) are preferable from the viewpoint of molecular stability.

In formulae (Ar-16) to (Ar-23), Y ¹ Nitrogen atom and Z which may be bonded thereto ⁰ Together form an aromatic heterocyclic group. Examples of the aromatic heterocyclic group include the groups described above as the aromatic heterocyclic group that Ar may have, and examples thereof include a pyrrole ring, an imidazole ring, a pyrroline ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, an indole ring, a quinoline ring, an isoquinoline ring, a purine ring, and a pyrrolidine ring. The aromatic heterocyclic group may have a substituent. In addition, Y ¹ Nitrogen atom and Z which may be bonded thereto ⁰ Together with the above-mentioned optionally substituted polycyclic aromatic hydrocarbon group or polycyclic aromatic heterocyclic group. Examples thereof include a benzofuran ring, a benzothiazole ring, and a benzoxazole ring.

The compound represented by the formula (X) can be produced, for example, according to the method described in Japanese patent application laid-open No. 2010-31223.

In the present invention, as the polymerizable liquid crystal compound for forming the retardation film, in addition to or in addition to the compound represented by the formula (X), for example, polymerizable liquid crystal compounds as described in Japanese patent application laid-open Nos. 2010-31223, 2010-270108, 2011-6360 and 2011-207765, that is, so-called polymerizable liquid crystal compounds exhibiting positive wavelength dispersibility, and the like can be used. These polymerizable liquid crystal compounds may be used after horizontal alignment or after vertical alignment.

The content of the polymerizable liquid crystal compound in the composition for forming a retardation film is, for example, 70 to 99.5 parts by mass, preferably 80 to 99 parts by mass, more preferably 85 to 98 parts by mass, and still more preferably 90 to 95 parts by mass, per 100 parts by mass of the solid content of the composition for forming a retardation film. When the content of the polymerizable liquid crystal compound is within the above range, it is advantageous from the viewpoint of alignment properties of the obtained retardation film. When the composition for forming a retardation film contains 2 or more polymerizable liquid crystal compounds, the total amount of all the liquid crystal compounds contained in the composition for forming a retardation film is preferably within the above content range.

The composition for forming a retardation film may contain a polymerization initiator for initiating a polymerization reaction of the polymerizable liquid crystal compound. The polymerization initiator may be suitably selected from polymerization initiators conventionally used in this field, and may be a thermal polymerization initiator or a photopolymerization initiator, and is preferably a photopolymerization initiator in view of being able to initiate a polymerization reaction under a lower temperature condition. The same photopolymerization initiators as those exemplified above as photopolymerization initiators usable in the polarizing film-forming composition are suitable.

The composition for forming a retardation film is usually applied to a substrate film or the like in a state of being dissolved in a solvent, and therefore preferably contains a solvent. The solvent is preferably a solvent capable of dissolving the polymerizable liquid crystal compound, and is preferably a solvent inactive to the polymerization reaction of the polymerizable liquid crystal compound. The solvent may be the same as the solvent used in the polarizing film-forming composition exemplified above.

The composition for forming a retardation film may contain a photosensitizer, a leveling agent, an additive exemplified as an additive contained in the composition for forming a polarizing film, and the like as needed. Examples of the photosensitizer and the leveling agent include the same photosensitizers and leveling agents as those used in the polarizing film-forming composition as exemplified above.

The composition for forming a retardation film can be prepared, for example, by mixing and stirring a polymerizable liquid crystal compound and a polymerization initiator, a solvent, an additive, and the like which are used as necessary.

The retardation film can be obtained by, for example, applying the composition for forming a retardation film on the 2 nd substrate, the alignment film or the peeling force adjusting layer, drying the coating film, aligning the polymerizable liquid crystal compound in the composition for forming a retardation film, and then polymerizing the polymerizable liquid crystal compound by light irradiation or the like while maintaining the aligned state. The alignment film may be the same as the alignment film previously exemplified as the alignment film that can be used in the production of the polarizing film of the present invention, and may be appropriately selected depending on a desired alignment regulating force and the like. Examples of methods that can be used for applying the composition for forming a retardation film, curing the polymerizable liquid crystal compound by light irradiation, and the like include the same methods as those exemplified for the method for forming a polarizing film.

In the optical laminate of the present invention, the thickness of the retardation film may be appropriately selected depending on the display device to be used, but is preferably 0.1 to 10 μm, more preferably 0.5 to 5 μm, and still more preferably 1 to 3 μm from the viewpoint of the reduction in thickness and the bending resistance suitable for use as a material for a flexible display. When the optical laminate of the present invention includes a plurality of retardation films, the thicknesses of the retardation films may be the same or different from each other, and preferably each of the thicknesses is within the above range.

In the case where the optical laminate of the present invention includes a retardation film having a 1/4 wavelength plate function and a retardation film formed of a liquid crystal cured film as a positive C plate, these retardation films may be bonded via an adhesive layer, but from the viewpoint of thinning of the optical laminate and a bending resistance suitable for use as a flexible display material, it is preferable that the retardation film formed of the liquid crystal cured film as the positive C plate is laminated with or without an alignment film having a vertical alignment regulating force interposed therebetween on the retardation film having the 1/4 wavelength plate function, or the retardation film formed of the 1/4 wavelength plate is laminated with or without an alignment film having a horizontal alignment regulating force interposed therebetween on the retardation film formed of the liquid crystal cured film as the positive C plate.

[ adhesive bonding layer ]

The adhesive layer disposed between the polarizing film and the retardation film in the present invention is a layer formed of an adhesive agent. The adhesive layer may be formed of a known adhesive agent as long as it can function as a layer for bonding the polarizing film and the retardation film. In one embodiment of the present invention, the adhesive bonding layer is formed of an adhesive composition.

Examples of the adhesive composition include those containing, as a main component, a resin such as a (meth) acrylic resin, a rubber resin, a urethane resin, an ester resin, a silicone resin, or a polyvinyl ether resin. Among them, a pressure-sensitive adhesive composition containing a (meth) acrylic resin as a base polymer, which is excellent in transparency, weather resistance, heat resistance, and the like, is preferable.

As the (meth) acrylic resin (base polymer) used in the adhesive composition, for example, a polymer or copolymer containing 1or 2 or more kinds of (meth) acrylic acid esters such as butyl (meth) acrylate, ethyl (meth) acrylate, isooctyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate as monomers can be suitably used. It is preferred to copolymerize the polar monomer with the base polymer. Examples of the polar monomer include monomers having a carboxyl group, a hydroxyl group, an amide group, an amino group, an epoxy group, and the like, such as (meth) acrylic acid, 2-hydroxypropyl (meth) acrylate, hydroxyethyl (meth) acrylate, (meth) acrylamide, N-dimethylaminoethyl (meth) acrylate, and glycidyl (meth) acrylate.

The adhesive composition may contain only the above-mentioned base polymer, or may contain a crosslinking agent. Examples of the crosslinking agent include a crosslinking agent which is a metal ion having a valence of 2 or more and forms a metal carboxylate salt with a carboxyl group; a crosslinking agent which is a polyamine compound and forms an amide bond with a carboxyl group; a crosslinking agent which is a polyepoxy compound, a polyol, and forms an ester bond between the polyepoxy compound and a carboxyl group; a crosslinking agent which is a polyisocyanate compound and forms an amide bond with a carboxyl group.

The pressure-sensitive adhesive composition may contain a solvent as needed, and examples of the solvent include solvents that can be used in a polarizing film-forming composition and the like.

The thickness of the adhesive layer is usually 1 to 40 μm, preferably 3 to 25 μm.

When the polarizing film and the phase difference film are laminated, the slow axis (optical axis) of the phase difference film and the absorption axis of the polarizing film are preferably laminated so as to be substantially 45 °. By laminating the retardation film such that the slow axis (optical axis) of the retardation film and the absorption axis of the polarizing film are substantially 45 °, a function as a circularly polarizing plate can be obtained. The angle is substantially 45 °, and is usually in the range of 45 ± 5 °.

[ optical laminate ]

The optical laminate of the present invention can be produced by forming and laminating the 1 st substrate, the alignment film, the polarizing film, the adhesive layer, the retardation film, and the 2 nd substrate, and the peeling force adjusting layer used as needed in an appropriate order in accordance with the production method described above for each layer, in order to form a desired configuration depending on the application or the like.

For example, a laminate is produced in which a peeling force adjusting layer is formed on the 1 st substrate, and a polarizing film is provided on the peeling force adjusting layer with an alignment film interposed therebetween. In addition, an optical laminate including the 1 st substrate, the peeling force adjusting layer, the alignment film, the polarizing film, the adhesive bonding layer, the phase difference film, the alignment film, the peeling force adjusting layer and the 2 nd substrate as shown in fig. 2 can be obtained by preparing a laminate in which the peeling force adjusting layer is formed on the 2 nd substrate, the phase difference film is provided on the peeling force adjusting layer with the alignment film interposed therebetween, and bonding the laminate having the polarizing film and the laminate having the phase difference film with an adhesive.

In the optical laminate of the present invention, the total film thickness of the polarizing film, the adhesive layer and the retardation film is preferably 20 μm or less, and more preferably 15 μm or less.

The optical laminate of the present invention may be in the form of a long film or a single sheet.

In the optical laminate of the present invention, both the peelable 1 st substrate and the peelable 2 nd substrate constituting the optical laminate are peeled off, and only the laminate structure having the circularly polarizing plate function is transferred to a transfer target and used. In the optical laminate of the present invention, the peeling forces F1 and F2 are controlled to be within predetermined ranges, and a difference of the predetermined ranges is provided between the 2 peeling forces, whereby the 1 st base material and the 2 nd base material can be easily peeled in a desired order while suppressing a zipper phenomenon and lifting of a peeling interface which are likely to occur at the time of transfer. In particular, even when the optical laminate is long, a desired peeling force can be easily maintained over the entire length thereof. Therefore, even when the 1 st base material and/or the 2 nd base material are continuously peeled off by the Roll to Roll method using an apparatus generally used in this field, the effect of suppressing the occurrence of the zipper phenomenon and the lift-off at the peeling interface at the peeling time is excellent without setting special conditions or the like.

The optical laminate of the present invention can be produced by using a general apparatus which has been widely used in the field for producing optical films, optical laminates, and the like, and can easily and continuously peel the 1 st base material or the 2 nd base material from the optical laminate in a desired order, and is less likely to cause a zipper phenomenon and lifting of a peel interface in the transferred laminate, and therefore, is suitable for producing a long optical film using a Roll to Roll system.

The present invention includes a method of manufacturing a long optical film, the method including:

a step of manufacturing a long optical laminate roll in which the optical laminate of the present invention is wound in a roll shape; and

The method of manufacturing a long optical laminate roll may further include:

Examples of the 3 rd substrate used in the above method include a resin film, a separator, a pellicle film, and the like which can be used as the 1 st substrate and/or the 2 nd substrate. The release film may be a film having an adhesive layer on the side opposite to the side adjacent to the substrate.

The optical laminate of the present invention is suitable as an elliptically polarizing plate because it is less likely to cause a zipper phenomenon due to the peeling of the 1 st substrate and the 2 nd substrate, or lifting of the peeling interface, and the optical performance of the laminate after transfer is excellent. Accordingly, the present invention is also directed to an elliptically polarizing plate comprising the optical laminate of the present invention. The elliptically polarizing plate of the present invention can be used in a variety of display devices.

The display device is a device having a display element, and includes a light-emitting element or a light-emitting device as a light-emitting source. Examples of the display device include a liquid crystal display device, an organic Electroluminescence (EL) display device, an inorganic Electroluminescence (EL) display device, a touch panel display device, an electron emission display device (e.g., an electric field emission display device (FED), a surface field emission display device (SED)), electronic paper (a display device using electronic ink, an electrophoretic element, a plasma display device, a projection display device (e.g., a Grating Light Valve (GLV) display device, a display device having a Digital Micromirror Device (DMD)), a piezoelectric ceramic display, and the like; the liquid crystal display device may include any display device such as a transmissive liquid crystal display device, a semi-transmissive liquid crystal display device, a reflective liquid crystal display device, a direct-viewing liquid crystal display device, and a projection liquid crystal display device; these display devices may be display devices that display two-dimensional images, a stereoscopic display device that displays a three-dimensional image may be used. In particular, the elliptically polarizing plate of the present invention can be suitably used for an organic Electroluminescence (EL) display device and an inorganic Electroluminescence (EL) display device, and can also be suitably used for a liquid crystal display device and a touch panel display device. These display devices can exhibit excellent image display characteristics because of the elliptically polarizing plate of the present invention, in which the zipper phenomenon and the lifting of the peeling interface are not easily generated.

The optical laminate of the present invention is also advantageous as an optical laminate for forming a flexible display material because it can transfer a thin optical laminate to another substrate while suppressing the occurrence of a zipper phenomenon and lift-off at a peeling interface even when the optical laminate is required to be thin and resistant to bending, and because a high circular polarization function and optical characteristics can be expected in the laminate after transfer. Accordingly, the present invention is also directed to a flexible display material comprising the optical laminate of the present invention. The flexible display material of the present invention can be suitably incorporated into a flexible image display device.

Examples

The present invention will be described in further detail below with reference to examples and comparative examples. In examples and comparative examples, "%" and "part(s)" are "% by mass" and "part(s) by mass" unless otherwise specified.

1. Production of laminate comprising polarizing film (polarizing film laminate)

(1) Production of laminate A1

(i) Preparation of resin composition (1) for Forming Release force adjusting layer

The following components were mixed and stirred at 50 ℃ for 4 hours to obtain a resin composition (1) for forming a peeling force adjusting layer.

■ A multifunctional acrylate compound of the following structure: 50 portions of

Dipentaerythritol hexaacrylate ("NK Ester a-DPH"), manufactured by shinkamura chemical corporation), the number of atoms connecting the branching point closest to the acryloyl group in the branched structure and the chain of the acryloyl group was 2.

[ solution 15]

Urethane acrylate polymer: 50 portions of

Urethane acrylate (manufactured by Daicel Ornex, "EBECRYL 4858"), functional group number 2, weight average molecular weight Mw 450, and functional group number per unit molecular weight 44.4X 10 ^-4 。

Radical polymerization initiator: 3 portions of

2- [4- (methylthio) benzoyl ] -2- (4-morpholinyl) propane (product of BASF, "Irgacure 907")

■ solvent: 10 portions of

Methyl ethyl ketone

(ii) Preparation of composition for forming photo-alignment film

The following components were mixed, and the resulting mixture was stirred at 80 ℃ for 1 hour to obtain a composition (1) for forming a photoalignment film.

-photo-alignment polymer: 2 portions of

[ solution 16]

(the polymer described in Japanese patent laid-open publication No. 2013-033249, number average molecular weight: about 28200, Mw/Mn: 1.82)

■ solvent: 98 portions of

Ortho-xylene

(iii) Preparation of composition (1) for Forming polarizing film

The following components were mixed and stirred at 80 ℃ for 1 hour to obtain a composition (1) for forming a polarizing film. As the dichroic dye, an azo dye described in examples of Japanese patent application laid-open No. 2013-101328 is used.

■ polymerizable liquid crystal compound: a190 parts

[ solution 17]

■ polymerizable liquid crystal compound: a210 parts

[ solution 18]

■ dichroic dye: 2.5 portions of azo pigment A

[ solution 19]

(dichroic dye A)2.5 parts

■ dichroic dye: 2.5 portions of azo pigment B

[ solution 20]

(dichroic dye B)2.5 parts

■ dichroic dye: 2.5 portions of azo pigment C

[ solution 21]

(dichroic dye C)2.5 parts

■ photopolymerization initiator: 6 portions of

2-dimethylamino-2-benzyl-1- (4-morpholinylphenyl) -1-butanone (Irgacure 369; manufactured by Ciba Specialty Chemicals, Inc.)

■ leveling agent: 1.2 parts of

Polyacrylate Compound (BYK-361N; manufactured by BYK-Chemie Co., Ltd.)

■ solvent: 400 portions of

Ortho-xylene

(iv) Production of substrate with Release force adjusting layer (1)

The release-treated surface of the polyethylene terephthalate film (SP-PLR 382050 manufactured by LINTEC) subjected to release treatment was subjected to corona treatment using a substrate, and then the composition (1) for forming a release force adjusting layer was applied by a bar coating method (#230 mm/s). The obtained coating film of the composition (1) for forming a peeling force adjusting layer was irradiated with an exposure of 500mJ/cm using a UV irradiation apparatus (SPOT CURE SP-7; manufactured by USHIO MOTOR CO., Ltd.) ² Violet of (365nm reference)And (3) obtaining the base material with the peeling force adjusting layer (1). The thickness of the peeling force adjusting layer (1) measured by a laser microscope (OLS 3000, Olympas Co., Ltd.) was 1.5. mu.m.

(v) Production of polarizing film

Then, the surface of the peeling force adjusting layer (1) of the substrate with the peeling force adjusting layer (1) is subjected to corona treatment, and then the composition (1) for forming a photo-alignment film is applied and dried at 120 ℃ to obtain a dry coating film. The dried coating film was irradiated with polarized UV to form a photoalignment film, and a laminate having the 1 st base material/peeling force adjusting layer (1)/photoalignment film in this order was obtained. The polarized UV treatment was performed under the condition that the intensity measured at a wavelength of 365nm was 100mJ using a UV irradiation apparatus (SPOT CURE SP-7; manufactured by USHIO Motor Co., Ltd.). The thickness of the photo-alignment film measured by a laser microscope (OLS 3000, Olympas Co., Ltd.) was 100 nm.

The surface of the photo-alignment film of the laminate thus obtained was coated with the composition (1) for forming a polarizing film by a bar coating method, and the resulting laminate was dried by heating in a drying oven at 120 ℃ for 1 minute to change the polymerizable liquid crystal compound phase to a liquid phase, and then cooled to room temperature to change the polymerizable liquid crystal compound phase to a smectic liquid crystal state. Then, the coating film formed from the composition (1) for forming a polarizing film was irradiated with an exposure of 1000mJ/cm using a UV irradiation apparatus (SPOT CURE SP-7; manufactured by USHIO MOTOR CO., LTD.) ² And (365 nm) ultraviolet rays, thereby polymerizing the polymerizable liquid crystal compound contained in the dried coating film while maintaining the smectic liquid crystal state of the polymerizable liquid crystal compound, and forming a polarizing film (polarizing plate) from the dried coating film. The thickness of the polarizing film measured by a laser microscope (OLS 3000, Olympas Co., Ltd.) was 2.3. mu.m.

In this manner, a laminate a1 having the 1 st substrate/peeling force adjusting layer (1)/photo alignment film/polarizing film in this order was obtained.

(2) Laminate A2

(i) Preparation of composition (2) for Forming polarizing film

A polarizing film-forming composition (2) was obtained by the same procedure as in the preparation of the polarizing film-forming composition (1) except that the following solvents were used.

■ solvent: 250 portions of

Cyclopentanone

(ii) Preparation of composition for forming photo-alignment film

The following components were mixed, and the resulting mixture was stirred at 80 ℃ for 1 hour to obtain a composition (2) for forming a photoalignment film.

■ photo-alignment Polymer: 5 portions of

[ solution 22]

■ solvent: 95 parts of

Cyclopentanone

(iii) Production of photo-alignment film

As a substrate, a Zeonor (registered trademark) film (manufactured by ZEON corporation, japan) as a cycloolefin film was used. After this 1 st base material film was subjected to corona treatment, the composition (2) for forming a photo-alignment film was applied by a bar coating method and dried by heating in an oven at 60 ℃ for 1 minute. The obtained dry coating film was subjected to polarized UV irradiation treatment to form a photoalignment film on the 1 st substrate surface, and a laminate having the 1 st substrate/photoalignment film in this order was obtained. The polarized UV treatment was performed under the condition that the intensity measured at a wavelength of 365nm was 100mJ using a UV irradiation apparatus (SPOT CURE SP-7; manufactured by USHIO Motor Co., Ltd.). The film thickness of the photo-alignment film measured by a laser microscope (OLS 3000, Olympas Co., Ltd.) was 100 nm.

(iv) Production of polarizing film

The surface of the photo-alignment film of the laminate thus obtained was coated with the composition (2) for forming a polarizing film by a bar coating method (# 730 mm/s), and the resultant was dried by heating in an oven at 120 ℃ for 1 minute to change the polymerizable liquid crystal compound phase to a liquid phase, and then cooled to room temperature to change the polymerizable liquid crystal compound phase to a smectic phaseLiquid crystal state. Then, an exposure amount of 1200mJ/cm was measured by using a UV irradiation device (SPOT CURE SP-7; manufactured by USHIO MOTOR CO., Ltd.) ² Ultraviolet irradiation (365nm basis) is performed to polymerize the polymerizable liquid crystal compound contained in the dried coating film while maintaining the smectic liquid crystal state of the polymerizable liquid crystal compound, and a polarizing film (polarizing plate) is formed from the dried coating film. The thickness of the formed polarizing film was measured by a laser microscope (OLS 3000, Olympas Co., Ltd.) to obtain a thickness of 1.8. mu.m.

In this manner, a laminate a2 having the 1 st substrate, the optical alignment film, and the polarizing film in this order was obtained.

(3) Laminate A3

A laminate A3 having the 1 st substrate/peeling force adjusting layer (1)/photo-alignment film/polarizing film in this order was obtained in the same manner as the laminate a1, except that the peeling force adjusting layer (1) was laminated on the untreated surface side of the polyethylene terephthalate film (SP-PLR 382050 manufactured by LINTEC) whose one surface was subjected to release treatment as the substrate.

(4) Laminate A4

(i) Preparation of composition (2) for Forming Release force-adjusting layer

KBE-903 (manufactured by shin-Etsu Silicone) as a silane coupling agent was dissolved in an amount of 0.25 wt% based on o-xylene to prepare a composition (2) for forming a release force adjusting layer.

(ii) Production of polarizing film

The composition (2) for forming a peeling force adjusting layer was applied by a bar coating method to the surface of the untreated side of a polyethylene terephthalate film (SP-PLR 382050 manufactured by LINTEC) whose one surface was subjected to a mold release treatment, and dried in an oven at 120 ℃ for 1 minute to form a peeling force adjusting layer (2) (a layer containing a silane compound) having a thickness of 40 nm. Next, the composition (1) for forming a peeling force adjusting layer was applied by a bar coating method, and the coating film of the resin composition (1) for forming a peeling force adjusting layer was irradiated with an exposure amount of 500mJ/cm using a UV irradiation apparatus (SPOT CURE SP-7; manufactured by USHIO MOTOR K.K.) ² A (365 nm-based) ultraviolet ray to form a peeling force adjusting layer (1) and to obtain a layer (1) having a first substrate and a peeling force adjusting layer in this order (1:)2) A laminate of/the peeling force adjusting layer (1)/b. The thickness of the peeling force adjusting layer (1) measured by a laser microscope (OLS 3000, Olympas Co., Ltd.) was 1.5. mu.m.

Next, a laminate a4 including the 1 st substrate/peeling force adjusting layer (2)/peeling force adjusting layer (1)/photoalignment film/polarizing film in this order was obtained by the same procedure as the method for producing the photoalignment film and polarizing film in the laminate a 1.

(5) Laminate A5

(i) Preparation of composition (3) for Forming Release force-adjusting layer

KBM-5103 (made by shin-Etsu Silicone) as a silane coupling agent was dissolved in o-xylene to give a solution having a weight of 0.25 wt%, thereby preparing a composition (3) for forming a release force adjusting layer.

(ii) Production of polarizing film

A laminate a5 having the 1 st substrate/peeling force adjusting layer (3)/peeling force adjusting layer (1)/photo-alignment film/polarizing film in this order was obtained by the same procedure as the above-described method for producing the polarizing film laminate a4, except that the peeling force adjusting layer forming composition (3) was used instead of the peeling force adjusting layer forming composition (2). The thickness of the peeling force adjusting layer (3) was 40 nm.

(6) Laminate A6

A laminate a6 having the 1 st substrate/peeling force adjusting layer (2)/peeling force adjusting layer (1)/photo-alignment film/polarizing film in this order was obtained by the same procedure as the production method of the laminate a4, except that a polyethylene terephthalate film (manufactured by mitsubishi resin co., ltd., DIAFOIL) having a thickness of 100 μm was used as the 1 st substrate.

2. Production of a laminate comprising a retardation film (retardation film laminate)

(1) Production of laminate B1

(i) Preparation of composition (1) for Forming phase Difference film

The following components were mixed, and the resulting mixture was stirred at 80 ℃ for 1 hour to obtain a composition (1) for forming a retardation film.

The polymerizable liquid crystal compound X1 and the polymerizable liquid crystal compound X2 were synthesized by the method described in jp 2010-31223 a.

■ polymerizable liquid crystal compound: x180 parts

[ solution 23]

Polymerizable liquid crystal compound: x220 parts

[ solution 24]

■ polymerization initiator: 6 portions of

2-dimethylamino-2-benzyl-1- (4-morpholinylphenyl) -1-butanone (Irgacure (registered trademark) 369; manufactured by Ciba Specialty Chemicals Co., Ltd.)

■ leveling agent: 0.1 part

Polyacrylate Compound (BYK-361N; manufactured by BYK-Chemie Co., Ltd.)

■ solvent: 400 portions of

Cyclopentanone

(ii) Production of retardation film

A laminate having the 2 nd substrate/peeling force adjusting layer (1)/photoalignment film was obtained by the same procedure as the method for producing the laminate having the 1 st substrate/peeling force adjusting layer (1)/photoalignment film in this order of the polarizing film laminate a1, except that the photoalignment film-forming composition (2) was used instead of the photoalignment film-forming composition (1).

The surface of the photo-alignment film of the laminate thus obtained was coated with the phase difference film-forming composition (1) by a bar coating method, heated and dried in an oven at 120 ℃ for 1 minute, and then cooled to room temperature to obtain a dried coating film. The obtained dried coating film was irradiated with an exposure of 1000mJ/cm using a UV irradiation apparatus (SPOT CURE SP-7; manufactured by USHIO MOTOR Co., Ltd.) ² Ultraviolet rays (365nm basis) form a retardation film obtained by curing a polymerizable liquid crystal compound in a state of being aligned in a horizontal direction in a substrate plane. Using a laser microscope (Olympas strain)OLS3000, manufactured by CO.) was measured, and the thickness of the formed retardation film was 2.0. mu.m.

In this manner, a laminate B1 having the 2 nd substrate/peeling force adjusting layer (1)/photo alignment film/retardation film in this order was obtained.

(2) Production of laminate B2

The surface of the photo-alignment film of the laminate obtained by the same procedure as the method for producing the laminate having the 1 st base material/photo-alignment film in this order of the laminate a2 was coated with the phase difference film-forming composition (1) by a bar coating method, heated and dried in an oven at 120 ℃ for 1 minute, and then cooled to room temperature to obtain a dried coating film. The obtained dried coating film was irradiated with an exposure of 1000mJ/cm using a UV irradiation apparatus (SPOT CURE SP-7; manufactured by USHIO MOTOR Co., Ltd.) ² Ultraviolet rays (365nm basis) form a retardation film obtained by curing a polymerizable liquid crystal compound in a state of being aligned in a horizontal direction in a substrate plane. The thickness of the retardation film thus formed was measured by a laser microscope (OLS 3000, Olympas Co., Ltd.) to be 2.0. mu.m.

In this manner, a laminate B2 having the 2 nd substrate, the photo-alignment film, and the retardation film in this order was obtained.

(3) Production of laminate B3

A laminate B3 having the 2 nd substrate/peeling force adjusting layer (1)/photo alignment film/retardation film in this order was obtained in the same manner as the laminate B1, except that the peeling force adjusting layer (1) was laminated on the untreated surface side of the polyethylene terephthalate film, one surface of which was subjected to the release treatment.

(4) Production of laminate B4

On the surface of the peeling force adjusting layer (1) of the laminate obtained in the same manner as the method for producing the laminate having the 1 st base material/peeling force adjusting layer (2)/peeling force adjusting layer (1) in this order of the laminate a4, a photo-alignment film and a retardation film were produced by the same procedure as the method for producing the photo-alignment film and the retardation film of the laminate B1.

In this manner, a laminate B4 having the 2 nd substrate/peeling force adjusting layer (2)/peeling force adjusting layer (1)/photo-alignment film/retardation film in this order was obtained.

(5) Production of laminate B5

A laminate B5 having the 2 nd substrate/peeling force adjusting layer (3)/peeling force adjusting layer (1)/photo alignment film/retardation film in this order was obtained in the same manner as the production method of the laminate B4, except that the peeling force adjusting layer forming composition (3) was used instead of the peeling force adjusting layer forming composition (2).

(6) Laminate B6

A laminate B6 having the 2 nd substrate/peeling force adjusting layer (2)/peeling force adjusting layer (1)/photo-alignment film/retardation film in this order was obtained in the same manner as in the production method of the laminate B4, except that a polyethylene terephthalate film (manufactured by mitsubishi resin co., ltd., DIAFOIL) having a thickness of 100 μm was used as the 2 nd substrate.

3. Production of optical laminate

Optical laminates of examples 1 to 8 and comparative examples 1 to 5 were produced by laminating laminates a1 to a6 as polarizing film laminates and laminates B1 to B6 as phase difference film laminates in the combinations described in table 1. For the lamination of the polarizing film laminate and the phase difference film laminate, the polarizing film side of the polarizing film laminate and the phase difference film side of the phase difference film laminate are laminated with an adhesive.

As the adhesive for bonding the polarizing film laminate and the phase difference film laminate, a sheet-like adhesive (NCF # L2, manufactured by linetec corporation) was used. The thickness of the adhesive layer was 5 μm.

4. Method for measuring peeling force

The peeling force F1 when the 1 st base material was peeled from the optical laminate and the peeling force F2 when the 2 nd base material was peeled from the optical laminate were measured by the following methods. The results are shown in table 1.

One end of a test piece (width 25 mm. times. length about 150mm) in the longitudinal direction was clamped by a tensile tester, and the test piece was subjected to a tensile test at a crosshead speed (jig moving speed) of 200 mm/min in an atmosphere of 23 ℃ and 60% relative humidity in accordance with JIS K6854-1: 1999 adhesive-peel adhesion Strength test method-part 1: 90 degree peel test of 90 degree peel.

5. Evaluation of peelability

Test pieces having a width of about 50mm × a length of about 200mm were cut from each of the optical laminates produced in examples and comparative examples. The substrate was peeled off at a jig moving speed of 5 m/min in an atmosphere of 23 ℃ and 60% relative humidity by holding the edge of the substrate to be peeled off with a tensile tester (TJ-95, manufactured by Tayoda, Ltd.). The peelability was evaluated by the following criteria.

< criterion for evaluation of Release Property >

A: the generation rate of the lifting and zipper phenomena of the stripping interface is less than 5% of the test length.

B: the phenomena of lifting and zipper at the stripping interface are generated. The yield was 5% or more and less than 50% of the test length.

C; the phenomena of lifting and zipper at the stripping interface are generated. The productivity was 50% or more of the test length.

6. Visual inspection

In the optical laminate obtained in examples and comparative examples, the 1 st substrate and the 2 nd substrate were peeled off, and an aluminum plate was bonded to the surface from which the 2 nd substrate was peeled off via a pressure-sensitive adhesive. The optical laminate to be bonded was observed for the presence or absence of unevenness from the front-surface vertical direction and the position at an angle of elevation of 50 ° with respect to the front-surface vertical direction.

< evaluation criteria of appearance >

A: no inhomogeneities were observed.

B: the unevenness was observed at an elevation angle of 50 ° with respect to the front vertical direction.

C; the unevenness was observed in the front vertical direction and at a position at an elevation angle of 50 ° with respect to the front vertical direction.

[ Table 1]

Claims

1. An optical laminate comprising a1 st substrate, an alignment film, a polarizing film, an adhesive layer, a retardation film and a2 nd substrate in this order,

a peeling force F1 when the 1 st base material is peeled from the optical laminate and a peeling force F2 when the 2 nd base material is peeled from the optical laminate satisfy formulae (1), (2), and (3):

0.02N/25mm≤F1≤0.30N/25mm (1)

0.02N/25mm≤F2≤0.30N/25mm (2)

0.02N/25mm≤|F1-F2| (3)。

2. the optical stack of claim 1,

a peeling force adjusting layer is provided on at least one of the surface of the No. 1 substrate on the polarizing film side and the surface of the No. 2 substrate on the phase difference film side.

3. The optical stack of claim 2,

the peeling force adjusting layer is a layer containing a silane compound or a hard coat layer.

4. The optical stack according to any one of claims 1 to 3,

the thickness of the No. 1 substrate is 20 μm or more and 100 μm or less.

5. The optical stack according to any one of claims 1 to 4,

the thickness of the No. 2 substrate is 20 μm to 100 μm.

6. The optical stack according to any one of claims 1 to 5,

the 1 st substrate is a resin film formed of at least 1 kind selected from a cellulose-based resin, a cycloolefin-based resin, and a polyethylene terephthalate resin.

7. The optical stack according to any one of claims 1 to 6,

the 2 nd substrate is a resin film formed of at least 1 kind selected from a cellulose-based resin, a cycloolefin-based resin, and a polyethylene terephthalate resin.

8. The optical stack according to any one of claims 1 to 7,

the polarizing film is a cured film of a polymerizable liquid crystal composition containing a polymerizable liquid crystal compound and a dichroic dye.

9. The optical stack according to any one of claims 1 to 8,

the retardation film satisfies formula (4):

120nm≤Re(550)≤170nm (4)

in the formula, Re (λ) represents an in-plane retardation value of the retardation film at a wavelength λ nm.

10. The optical stack of claim 9 further comprising a liquid crystal cured film as a positive C-plate.

11. The optical stack according to any one of claims 1 to 10,

the total film thickness of the polarizing film, the adhesive layer and the retardation film is 20 μm or less.

12. A method of manufacturing a long-sized optical film, comprising:

a step of manufacturing a long optical laminate roll in which the optical laminate according to any one of claims 1 to 11 is wound in a roll shape; and

and a1 st peeling step of continuously peeling, from the long optical laminate roll, one of a1 st base material and a2 nd base material constituting the optical laminate, which has a smaller peeling force when peeled from the optical laminate.

13. The method of manufacturing an elongated optical film according to claim 12, further comprising:

and a2 nd peeling step of peeling off the 1 st substrate or the 2 nd substrate which is not peeled off in the 1 st peeling step.

14. An elliptically polarizing plate comprising the optical stack of any of claims 1 to 11.

15. A flexible display material comprising the optical stack of any one of claims 1-11.