KR102532379B1 - Manufacturing method of optically anisotropic layer - Google Patents

Abstract

The present invention provides a method for producing an optically anisotropic layer capable of producing an image display device having excellent durability and film contrast and excellent panel contrast. The method for producing an optically anisotropic layer of the present invention comprises: step A of forming an uncured layer containing a polymerizable liquid crystal compound; step B of forming a nematic phase by subjecting the uncured layer to heat treatment; Process C of forming a smectic phase by subjecting the uncured layer in which the tick-like phase is formed to a cooling process, and process D of forming a semi-cured layer by performing a first exposure process on the uncured layer in which the smectic phase is formed and Step E of subjecting the semi-cured layer to a second exposure process under a temperature condition higher than the temperature at the time of the first exposure process to form an optically anisotropic layer.

Description

Manufacturing method of optically anisotropic layer

The present invention relates to a method for producing an optically anisotropic layer.

Optical films such as an optical compensation sheet and a retardation film are used in various image display devices to eliminate image discoloration and/or to enlarge a viewing angle.

Conventionally, a stretched birefringent film has been used as an optical film, but recently, an optically anisotropic layer formed using a liquid crystal compound has been proposed instead of a stretched birefringent film.

For example, Patent Document 1 discloses a method for manufacturing an optically anisotropic layer in which an optically anisotropic layer fixed in a smectic phase is produced. In the manufacturing method of Patent Document 1, an optically anisotropic layer is produced through a heating step, a cooling/heating step, and a polymerization step for an uncured layer made of a polymerizable liquid crystal composition (Claim 1).

Japanese Unexamined Patent Publication No. 2017-068005

An optically anisotropic layer is introduced into and used in electronic devices in many cases. Therefore, the optically anisotropic layer is required to have durability capable of exhibiting stable performance for a long period of time even under harsh environments such as high temperatures.

In addition, from the viewpoint of thinning, when an optically anisotropic layer is formed directly on a polarizer or through another layer (for example, an alignment film), an excellent contrast (hereinafter abbreviated as "film contrast") is also required for the optically anisotropic layer. It is becoming.

Further, when an image display device using a polarizing plate including a polarizer and an optically anisotropic layer is manufactured, excellent contrast (hereinafter abbreviated as "panel contrast") is required for the image display device to be manufactured.

Then, this invention has excellent durability and film contrast, and makes it a subject to provide the manufacturing method of the optically anisotropic layer which can manufacture the image display apparatus of excellent panel contrast.

MEANS TO SOLVE THE PROBLEM As a result of earnestly examining to solve the said subject, the present inventors discovered that the said subject was solvable by the following structure.

〔One〕

Step A of forming an uncured layer containing a polymerizable liquid crystal compound;

Step B of subjecting the uncured layer to heat treatment to form a nematic phase;

Step C of forming a smectic phase by subjecting the uncured layer in which the nematic phase is formed to a cooling treatment;

Step D of forming a semi-cured layer by subjecting the uncured layer in which the smectic phase is formed to a first exposure process;

A method for producing an optically anisotropic layer having step E of subjecting the semi-cured layer to a second exposure treatment under a temperature condition higher than the temperature at the time of the first exposure treatment to form an optically anisotropic layer.

〔2〕

The manufacturing method of the optically anisotropic layer as described in [1], wherein the cooling rate of the uncured layer in the step C is 1 to 100°C/min.

[3]

The method for producing an optically anisotropic layer according to [1] or [2], wherein the cooling rate of the uncured layer in step C is 1 to 60°C/min.

〔4〕

The method for producing an optically anisotropic layer according to any one of [1] to [3], wherein the temperature of the uncured layer gradually decreases in the step C.

[5]

The method for producing an optically anisotropic layer according to any one of [1] to [4], wherein the light used for the first exposure treatment is an ultraviolet ray.

[6]

The method for producing an optically anisotropic layer according to any one of [1] to [5], wherein the exposure amount in the first exposure treatment is 1 to 60 mJ/cm ² .

[7]

The method for producing an optically anisotropic layer according to any one of [1] to [6], wherein the exposure amount in the first exposure treatment is 10 to 30 mJ/cm ² .

〔8〕

The method for producing an optically anisotropic layer according to any one of [1] to [7], wherein the temperature during the second exposure treatment is higher than the phase transition temperature between the smectic phase and the nematic phase of the polymerizable liquid crystal compound.

[9]

The method for producing an optically anisotropic layer according to any one of [1] to [8], wherein a difference between the temperature during the first exposure process and the temperature during the second exposure process is 20°C or higher.

[10]

The method for producing an optically anisotropic layer according to any one of [1] to [9], wherein a difference between the temperature during the first exposure process and the temperature during the second exposure process is 40°C or higher.

[11]

The method for producing an optically anisotropic layer according to any one of [1] to [10], wherein the uncured layer contains an oxime ester polymerization initiator.

ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the optically anisotropic layer which has excellent durability and film contrast, and can produce an image display device with excellent panel contrast can be provided.

Hereinafter, the present invention will be described in detail.

The description of the constitutional requirements described below may be made based on typical embodiments of the present invention, but the present invention is not limited to such embodiments.

In addition, in this specification, the numerical range expressed using "-" means the range which includes the numerical value described before and after "-" as a lower limit and an upper limit.

In this specification, when referring to the temperature of a layer (such as an uncured layer to be described later), it is intended that the temperature of the surface of the layer is measured with a radiation thermometer.

In this specification, the smectic phase refers to a state in which molecules aligned in one direction have a layered structure, and the nematic phase refers to a state in which the constituent molecules have orientation order but no three-dimensional positional order. say

In the present specification, the phase transition temperature is observed while heating or cooling the uncured layer formed on the alignment film using a central processor FP90 (Mettler TOLEDO) and an optical microscope, and the temperature at which the phase change occurs It was set as the phase transition temperature.

The uncured layer will be described later.

In the present invention, Re(λ) and Rth(λ) respectively represent in-plane retardation and thickness direction retardation at wavelength λ. For example, Re(450) represents in-plane retardation at a wavelength of 450 nm. When there is no description in particular, the wavelength λ is 550 nm.

In the present invention, Re(λ) and Rth(λ) are values measured at a wavelength λ in AxoScan OPMF-1 (manufactured by Opto Science). By entering the average refractive index ((nx + ny + nz) / 3) and film thickness (d (μm)) in AxoScan,

Slow axis direction (°)

Re(λ)=R0(λ)

Rth(λ)=((nx+ny)/2-nz)×d

is calculated

In addition, R0(λ) is expressed as a numerical value calculated by AxoScan OPMF-1 unless otherwise specified, but means Re(λ).

In this specification, the refractive indices nx, ny, and nz are measured using an Abbe refractive index (NAR-4T, manufactured by Atago Co., Ltd.) and using a sodium lamp (λ = 589 nm) as a light source. In the case of measuring the wavelength dependence, it can be measured with a multi-wavelength Abbe refractometer DR-M2 (manufactured by Atago Co., Ltd.) in combination with an interference filter.

In addition, values from the polymer handbook (JOHN WILEY & SONS, INC) and catalogs of various optical films can be used. The values of the average refractive index of the main optical films are exemplified below: cellulose acylate (1.48), cycloolefin polymer (1.52), polycarbonate (1.59), polymethylmethacrylate (1.49), and polystyrene (1.59).

In addition, in this specification, the bonding direction of the divalent group (for example, -CO-O-) shown is not specifically limited, For example, ^L1 in general formula (W) mentioned later is -CO-O In the case of -, if the position coupled to the P ¹ side is *1 and the position coupled to the Sp ¹ side is *2, L ¹ may be *1-CO-O-*2, or *1-O It may be -CO-*2.

[Method for producing optically anisotropic layer]

The manufacturing method of the optically anisotropic layer of this invention has the following steps A-E.

Step A: Step of forming an uncured layer containing a polymerizable liquid crystal compound (layer formation step).

Step B: Step B of forming a nematic phase by subjecting the uncured layer to heat treatment (nematic phase forming step).

Step C: A step of forming a smectic phase by subjecting the uncured layer in which the nematic phase is formed to a cooling treatment (cooling step).

Step D: A step of forming a semi-cured layer by subjecting the uncured layer in which the smectic phase is formed to a first exposure treatment (first polymerization step).

Step E: Under a temperature condition higher than the temperature at the time of the first exposure treatment, the semi-cured layer is subjected to a second exposure treatment to form an optically anisotropic layer (second polymerization step).

Although the reason why the subject of the present invention can be solved by taking such a structure is not necessarily clear, the present inventors think as follows.

First, in the present invention, by performing the first exposure treatment on an uncured layer in a smectic phase state after being cooled to a temperature below the phase transition temperature between the smectic phase and the nematic phase, excellent orientation of the smectic phase can be fixed, and finally obtained Packing of molecules in the optically anisotropic layer becomes good. Therefore, the optically anisotropic layer of the present invention is excellent in film contrast, and when introduced into an image display device and used, an image display device having excellent panel contrast is obtained.

In addition, after making the uncured layer into a semi-cured layer by the first exposure treatment, the temperature in the first exposure treatment is simply performed by performing the second exposure treatment on the semi-cured layer obtained at a higher temperature than the first exposure treatment. It is thought that an optically anisotropic layer having a higher polymerization rate and excellent durability was obtained than by continuing the exposure.

Hereinafter, each step of the manufacturing method of the optically anisotropic layer of the present invention will be described in detail.

[Manufacturing process of optically anisotropic layer]

<Process A (layer formation process)>

Step A (layer formation step) is a step of forming an uncured layer containing a polymerizable liquid crystal compound.

The uncured layer is a layer that contains a polymerizable liquid crystal compound and has not been subjected to curing treatment such as the first exposure treatment and the second exposure treatment described later. As will be described later, the uncured layer shows a nematic phase and a smectic phase in this order on the lower temperature side than the isotropic phase.

When forming the uncured layer, it is preferable to form the uncured layer using a polymerizable liquid crystal composition containing a polymerizable liquid crystal compound. More specifically, the uncured layer is preferably formed by applying a polymerizable liquid crystal composition on a substrate, for example. As a base material, a support body and a polarizer are mentioned. Moreover, an orientation film may be further arrange|positioned on the support body.

Each component included in the polymerizable liquid crystal composition will be described in detail in the latter part.

The method of applying the polymerizable liquid crystal composition is not particularly limited, and a known method can be employed. For example, a screen printing method, a dip coating method, a spray coating method, a spin coating method, an ink jet method, a gravure offset printing method, and a flexographic printing method are exemplified.

In addition, after application of the polymerizable liquid crystal composition, a drying treatment for removing the solvent may be performed if necessary.

The application amount of the polymerizable liquid crystal composition may be appropriately adjusted according to the desired thickness of the optically anisotropic layer. For example, the coating amount at which the thickness of the uncured layer in a state in which the solvent or the like is removed is preferably 0.1 to 10 μm, and more preferably 0.5 to 5 μm.

<Process B (nematic phase formation process)>

Step B (nematic phase forming step) is a step of forming a nematic phase by subjecting the uncured layer to heat treatment.

The procedure of the nematic phase forming step is not particularly limited as long as the temperature of the uncured layer can be heated to a temperature equal to or higher than the phase transition temperature between the smectic phase and the nematic phase to form the uncured layer into a nematic phase.

The temperature of the uncured layer (first heating temperature) adjusted by the heating is equal to or higher than the phase transition temperature between the smectic phase and the nematic phase. The first heating temperature is preferably 0 to 83°C higher, more preferably 2 to 53°C higher, and 2 to 37°C higher than the phase transition temperature between the smectic phase and the nematic phase during heating. is more preferable

In addition, it is preferable that the uncured layer is maintained for a certain period of time in a state in which a nematic phase is formed. Such holding time is preferably 1 second to 10 minutes, more preferably 5 seconds to 5 minutes or less, and still more preferably 5 to 30 seconds. During the holding time, the temperature of the uncured layer is preferably maintained within a range of ±5°C from the first heating temperature.

In addition, the means for adjusting the temperature of the uncured layer is not particularly limited, and for example, a hot plate may be used or an oven may be used. The same applies to the temperature operation of each layer described in the steps below.

<Process C (cooling process)>

Step C (cooling step) is a step of forming a smectic phase by performing a cooling treatment on the uncured layer in which the nematic phase has been formed in step B (nematic phase forming step).

The temperature (cooling temperature) of the uncured layer subjected to the cooling process in the cooling step is not particularly limited as long as the uncured layer can form a smectic phase, and is higher than the temperature at which crystals start to form in the uncured layer. Higher temperatures are preferred. The cooling temperature is preferably 0 to 60°C lower than the phase transition temperature between the smectic phase and the nematic phase during temperature decrease, more preferably 2 to 25°C lower, and more preferably 5 to 15°C lower. desirable.

From the viewpoint of obtaining an image display device with better film contrast and panel contrast of the optically anisotropic layer, the cooling rate (cooling rate) of the uncured layer during cooling in the cooling step is preferably 0.5 to 200 ° C./min, 1-100 degreeC/min is more preferable, 1-80 degreeC/min is still more preferable, and 1-60 degreeC/min is especially preferable.

In addition, the cooling rate can be obtained by dividing the temperature difference between the first heating temperature and the cooling temperature by the time taken from the start of the cooling process to reaching the cooling temperature.

Moreover, in the cooling process, it is preferable that the temperature of the uncured layer gradually decreases. In addition, "the temperature gradually decreases" means that the temperature of the uncured layer decreases as a whole in the cooling step. In other words, it is intended that no significant temperature rise occurs in the uncured layer from the start of the temperature decrease until the cooling temperature is reached.

The cooling treatment method is not particularly limited, as long as the uncured layer forming the nematic layer can be made into a smectic phase. For example, the uncured layer forming the nematic layer is placed on a hot plate set higher than the phase transition temperature between the crystalline phase and the smectic phase and lower than the phase transition temperature between the smectic phase and the nematic phase, and placed on the uncured layer. A method of forming a smectic phase is exemplified.

<Step D (first polymerization step)>

Step D (first polymerization step) is a step of forming a semi-cured layer by performing a first exposure treatment on the uncured layer in which the smectic phase was formed in step C.

It is preferable that a smectic phase is formed in the entire uncured layer at the time of performing the first exposure treatment.

The light used for the first exposure treatment is preferably an ultraviolet ray, and the ultraviolet ray is preferably an ultraviolet ray including light having a wavelength of 365 nm.

Examples of the exposure light source include metal halide lamps, mercury lamps (medium pressure mercury lamps, high pressure mercury vapor lamps, ultra-high pressure mercury lamps, etc.), xenon lamps, carbon arc lamps, fluorescent lamps (ultraviolet fluorescent lamps, etc.), LEDs (light emitting diodes, ultraviolet LEDs, etc.) ), and LD (LD: laser diode, ultraviolet LD, etc.).

With respect to the light obtained from the exposure light source, you may limit the wavelength range to irradiate using an interference filter or a color filter. Moreover, it is good also considering light from such an exposure light source as polarization using a polarization filter or a polarization prism.

The exposure amount in the first exposure treatment is not particularly limited, as long as the semi-cured layer can be formed by polymerizing some of the polymerizable groups contained in the polymerizable liquid crystal compound as will be described later. Among them, the durability of the optical anisotropic layer, the film contrast, and the panel contrast when the optically anisotropic layer is introduced into an image display device are well-balanced and the exposure amount in the first exposure process (preferably, the wavelength is 300 to 390 nm). The integrated exposure amount) is preferably 0.5 to 100 mJ/cm ² , more preferably 1 to 60 mJ/cm ² , and even more preferably 10 to 30 mJ/cm ² .

Moreover, it is preferable to perform a 1st exposure process in an inert gas atmosphere, such as nitrogen gas, from a viewpoint of advancing a uniform polymerization reaction.

A semi-cured layer is obtained by the first exposure treatment described above. The semi-cured layer is a layer obtained by polymerizing some of the polymerizable groups contained in the polymerizable liquid crystal compound, and the polymerizable group derived from the polymerizable liquid crystal compound remains in the semi-cured layer. Especially, the residual ratio of the polymerizable group derived from the polymerizable liquid crystal compound after the first exposure treatment is preferably 10% or more, and more preferably 20% or more. The upper limit is preferably 90% or less, and more preferably 80% or less, as for the residual ratio of the polymerizable group after the first exposure treatment, in order to improve the durability after the second exposure treatment.

The residual ratio is obtained by comparing the amount of the polymerizable liquid crystal compound-derived polymerizable group in the semi-cured layer after the first exposure treatment with the amount of the polymerizable liquid crystal compound-derived polymerizable group in the uncured layer before the first exposure treatment. is calculated Specifically, by an infrared spectrophotometer, the peak derived from the polymerizable group in the uncured layer and the peak derived from the structure (eg, carbonyl group) in the polymerizable liquid crystal compound whose intensity does not change before and after exposure Calculate the ratio X. Similarly, the ratio Y of the peak derived from the polymerizable group in the semi-cured layer and the peak derived from the structure (for example, carbonyl group) in the polymerizable liquid crystal compound whose intensity does not change before and after exposure is calculated. Next, the residual rate can be calculated by the formula: Ratio Y/Ratio X×100.

<Step E (second polymerization step)>

Step E (second polymerization step) is a step of forming an optically anisotropic layer by subjecting the semi-cured layer to a second exposure treatment under a temperature condition higher than the temperature at the time of the first exposure treatment.

The temperature condition higher than the temperature during the first exposure treatment is limited to an environment in which the temperature of the semi-cured layer when the second exposure treatment is performed is higher than the temperature of the uncured layer when the first exposure treatment is performed. there is no

Usually, in order to achieve the said temperature condition, in a 2nd polymerization process, heat processing (2nd heat processing) is given to the semi-cured layer obtained through the 1st polymerization process. The second exposure treatment may be started simultaneously with the second heat treatment, or may be performed after the semi-cured layer reaches a predetermined temperature by the second heat treatment.

The second exposure treatment may be performed while raising the temperature of the semi-cured layer, or may be performed while maintaining the temperature of the semi-cured layer constant.

The temperature of the semi-cured layer increased by the second heat treatment (the temperature difference between the semi-cured layer before and after the second heat treatment. In other words, the difference between the temperature during the first exposure treatment and the temperature during the second exposure treatment) is obtained From the viewpoint of more excellent durability of the optically anisotropic layer, the temperature is preferably 10°C or higher, more preferably 20°C or higher, and still more preferably 40°C or higher. As for an upper limit, 160 degreeC or less is preferable.

The temperature (second heating temperature) of the semi-cured layer during the second exposure treatment is higher than or equal to the phase transition temperature between the smectic phase and the nematic phase during the heating of the uncured layer, in view of the superior durability of the obtained optically anisotropic layer. desirable.

The heating rate (heating rate) when the semi-cured layer is heated by the second heat treatment is preferably 0.5 to 250°C/minute, more preferably 50 to 200°C/minute, and still more preferably 75 to 150°C/minute.

In addition, the temperature increase rate can be obtained by dividing the temperature difference between the semi-cured layer before and after the second heat treatment by the time required for the second heat treatment.

The light used in the second exposure treatment is preferably an ultraviolet ray, and the ultraviolet ray is preferably an ultraviolet ray including light having a wavelength of 365 nm.

As the exposure light source, the same exposure light source as mentioned in the description of the first exposure process is exemplified.

With respect to the light obtained from the exposure light source, you may limit the wavelength range to irradiate using an interference filter or a color filter. Moreover, it is good also considering the light from these exposure light sources as polarization using a polarization filter or a polarization prism.

The exposure amount in the second exposure treatment (preferably the cumulative exposure amount at a wavelength of 300 to 390 nm) is preferably 100 to 10000 mJ/cm ² , more preferably 200 to 5000 mJ/cm ² , and 400 to 1500 mJ/cm ² more preferable

Further, the second exposure treatment is preferably performed under an inert gas atmosphere such as nitrogen gas from the viewpoint of advancing a uniform polymerization reaction.

In the optically anisotropic layer obtained by performing the second exposure treatment, substantially no polymerizable group derived from a polymerizable liquid crystal compound is contained. The above "substantially" means that the residual ratio of the polymerizable group derived from the polymerizable liquid crystal compound is 5% or less. The residual ratio is calculated by comparing the amount of polymerizable groups derived from the polymerizable liquid crystal compound in the optically anisotropic layer with the amount of polymerizable groups derived from the polymerizable liquid crystal compound in the uncured layer before the first exposure treatment. Specifically, the method using the infrared spectrophotometer mentioned above is mentioned.

[Polymerizable liquid crystal composition]

In the production method of the present invention, it is preferable to use a polymerizable liquid crystal composition.

Hereinafter, the polymerizable liquid crystal composition will be described.

<Polymerizable liquid crystal compound>

A polymerizable liquid crystal composition contains a polymerizable liquid crystal compound.

At least one type of the polymerizable liquid crystal compound used herein is preferably a polymerizable liquid crystal compound capable of expressing a nematic phase and a smectic phase.

The polymerizable liquid crystal composition may contain other polymerizable liquid crystal compounds other than the polymerizable liquid crystal compound capable of expressing a nematic phase and a smectic phase, but the polymerizable liquid crystal composition as a whole can express a nematic phase and a smectic phase. It is necessary to be able to form an uncured layer.

A polymerizable liquid crystal compound is a liquid crystal compound having at least one polymerizable group.

In general, liquid crystal compounds can be classified into a rod-shaped type and a disk-shaped type based on their shapes. Also, there are types of low molecular weight and high molecular weight, respectively. Polymers generally refer to compounds with a polymerization degree of 100 or higher (Polymer Physics/Phase Transition Dynamics, Doi Masaozer, page 2, Iwanami Shoten, 1992).

As long as the polymerizable liquid crystal compound has a polymerizable group and can form an uncured layer capable of expressing a smectic phase, any liquid crystal compound can be used. Among them, it is preferable to use a rod-shaped polymerizable liquid crystal compound.

The polymerizable liquid crystal compound preferably has two or more polymerizable groups in one molecule. Moreover, when using 2 or more types of polymeric liquid crystal compounds, it is preferable that at least 1 type of polymerizable liquid crystal compound has 2 or more polymeric groups in 1 molecule.

In addition, after the liquid crystal compound is fixed by polymerization, it is not necessary to already exhibit liquid crystallinity, but the layer formed in this way is sometimes referred to as a liquid crystal layer for convenience.

The kind of polymerizable group that the polymerizable liquid crystal compound has is not particularly limited, and a functional group capable of undergoing an addition polymerization reaction is preferable, and a polymerizable ethylenically unsaturated group or ring polymerizable group is more preferable. For example, a (meth)acryloyl group, a vinyl group, a styryl group, an allyl group, an epoxy group, or an oxetane group is preferable, and among them, a (meth)acryloyl group is more preferable because the polymerization reaction is fast.

(Polymerizable liquid crystal compound capable of expressing smectic phase)

As a polymeric liquid crystal compound capable of expressing a smectic phase, for example, Japanese Unexamined Patent Publication No. 2016-051178, Japanese Unexamined Patent Publication No. 2008-214269, Japanese Unexamined Patent Publication No. 2008-019240, and Japanese Unexamined Patent Publication 2006- and the compounds described in 276821.

Moreover, as a rod-shaped polymeric liquid crystal compound, the polymeric liquid crystal compound which has a maximum absorption wavelength in the wavelength range of 330-380 nm is preferable.

Moreover, the rod-shaped polymerizable liquid crystal compound is preferably a polymerizable liquid crystal compound having reverse wavelength dispersion.

Here, in the present specification, the polymerizable liquid crystal compound having reverse wavelength dispersion means that the surface in a specific wavelength (visible light range) of the retardation film (optically anisotropic layer, etc.) produced using such a polymerizable liquid crystal compound When the retardation (Re) value is measured within, it refers to the property that the Re value becomes equal or higher as the measurement wavelength increases.

For example, a polymerizable liquid crystal compound capable of forming an optically anisotropic layer satisfying the following formula is preferable.

Re(450)/Re(550)<1.00

Especially, as a polymeric liquid crystal compound, the compound represented by General formula (W) is preferable.

P ¹ -L ¹ -Sp ¹ -L ² -(-A ¹ -L ³ -) _m -MG-(-L ⁴ -A ² -) _n -L ⁵ -Sp ² -L ⁶ -P ² (W)

In general formula (W), m and n represent the integer of 1-3 each independently.

In General Formula (W), L ¹ , L ² , L ³ , L ⁴ , L ⁵ , and L ⁶ each independently represent a single bond or a divalent linking group.

As the divalent linking group, -CO-O-, -C(=S)O-, -CR ¹ R ² -, -CR ¹ R ² -CR ³ R ⁴ -, -O-CR ¹ R ² -, - CR ¹ R ² -O-CR ³ R ⁴ -, -CO-O-CR ¹ R ² -, -O-CO-CR ¹ R ² -, -CR ¹ R ² -O-CO-CR ³ R ⁴ - , -CR ¹ R ² -CO-O-CR ³ R ⁴ -, -NR ¹ -CR ² R ³ -, or -CO-NR ¹ - are preferred. R ¹ , R ² , R ³ and R ⁴ each independently represent a hydrogen atom, a fluorine atom, or an alkyl group having 1 to 4 carbon atoms.

When a plurality of L ^3s are present, the plurality of L ^3s may be the same or different. When a plurality of L ⁴ exist, the plurality of L ⁴ may be the same or different.

In the general formula (W), A ¹ and A ² each independently represent an aromatic ring group having 6 or more carbon atoms or an alicyclic hydrocarbon group having 5 or more carbon atoms (preferably 5 to 8 carbon atoms).

One or more of -CH ₂ - constituting the alicyclic hydrocarbon group may be substituted with -O-, -S- or -NH-.

When a plurality of A ¹ exists, the plurality of A ¹ 's may be the same or different. When a plurality of A ² exists, the plurality of A ^{2 '} s may be the same or different.

As the alicyclic hydrocarbon group having 5 or more carbon atoms represented by A ¹ and A ² , a 5- or 6-membered ring group is preferable. Moreover, although saturated or unsaturated may be sufficient as an alicyclic hydrocarbon group, a saturated alicyclic hydrocarbon group is preferable.

As an alicyclic hydrocarbon group, a cyclohexane ring group (such as a cyclohexane-1,4-diyl group) and a cyclohexene ring group are mentioned, for example.

In addition, as an alicyclic hydrocarbon group, description of Paragraph [0078] of Unexamined-Japanese-Patent No. 2012-021068 can be considered into consideration, and this content is integrated in this specification, for example.

Examples of aromatic rings having 6 or more carbon atoms represented by A ¹ and A ² include aromatic hydrocarbon rings such as benzene rings, naphthalene rings, anthracene rings, and phenanthroline rings; Aromatic heterocycles, such as a furan ring, a pyrrole ring, a thiophene ring, a pyridine ring, a thiazole ring, and a benzothiazole ring, are mentioned. Especially, a benzene ring (for example, 1, 4-phenylene group etc.) is preferable.

In the general formula (W), Sp ¹ and Sp ² each independently constitute a single bond, a linear or branched alkylene group having 1 to 12 carbon atoms, or a linear or branched alkylene group having 1 to 12 carbon atoms - One or more CH ₂ - represents a divalent linking group substituted for -O-, -S-, -NH-, -N(Q)-, or -CO-. Q represents a substituent (such as an alkyl group, an alkoxy group, or a halogen atom).

As a C1-C12 linear or branched alkylene group represented by said ^Sp1 and ^Sp2 , a methylene group, an ethylene group, a propylene group, or a butylene group etc. are preferable, for example.

In General Formula (W), P ¹ and P ² each independently represent a monovalent organic group, and at least one of P ¹ and P ² represents a polymerizable group. However, when MG is an aromatic ring represented by general formula (Ar-3) mentioned later, at least one of P ¹ and P ² and P ³ and P ⁴ in general formula (Ar-3) represents a polymerizable group.

The polymerizable group represented by P ¹ and P ² is not particularly limited, and a radical polymerizable group or a cationic polymerizable group is preferable.

As the radical polymerizable group, a generally known radical polymerizable group can be used. For example, an acryloyl group and a methacryloyl group are mentioned. In this case, the polymerization rate is generally high for the acryloyl group, and the acryloyl group is preferable from the viewpoint of productivity improvement. Moreover, a methacryloyl group can similarly be used as a polymeric group of a highly birefringent liquid crystal.

As the cationically polymerizable group, a generally known cationically polymerizable group can be used. Examples thereof include an alicyclic ether group, a cyclic acetal group, a cyclic lactone group, a cyclic thioether group, a spiro orthoester group, and a vinyloxy group. Especially, an alicyclic ether group or a vinyloxy group is preferable, and an epoxy group, an oxetanyl group, or a vinyloxy group is more preferable.

Examples of particularly preferred polymerizable groups include the following.

Among the following polymerizable groups, black circles indicate bonding positions.

[Formula 1]

In the general formula (W), MG represents any one of aromatic rings selected from the group consisting of groups represented by the following general formulas (Ar-1) to (Ar-5). In the following general formulas (Ar-1) to (Ar-5), *1 represents a bonding position with L ³ , and *2 represents a bonding position with L ⁴ .

[Formula 2]

Here, in the general formula (Ar-1), Q ¹ represents N or CH, Q ² represents -S-, -O-, or -N(R ⁵ )-, and R ⁵ represents, A hydrogen atom or an alkyl group of 1 to 6 carbon atoms is represented, and Y ¹ represents an aromatic hydrocarbon group of 6 to 12 carbon atoms or an aromatic heterocyclic group of 3 to 12 carbon atoms which may have a substituent.

Examples of the C1-C6 alkyl group represented by R ⁵ include methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, and an n-hexyl group.

As a C6-C12 aromatic hydrocarbon group represented by Y ^<1> , aryl groups, such as a phenyl group, a 2, 6- diethylphenyl group, and a naphthyl group, are mentioned, for example.

As a C3-C12 aromatic heterocyclic group represented by Y ^<1> , heteroaryl groups, such as a thienyl group, a thiazolyl group, a prill group, and a pyridyl group, are mentioned, for example.

Moreover, as a substituent which Y ¹ may have, an alkyl group, an alkoxy group, a halogen atom, etc. are mentioned, for example.

As the alkyl group, for example, a straight-chain, branched or cyclic alkyl group having 1 to 18 carbon atoms is preferable, and an alkyl group having 1 to 8 carbon atoms (eg, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group) , isobutyl group, sec-butyl group, t-butyl group, cyclohexyl group, etc.) are more preferable, an alkyl group having 1 to 4 carbon atoms is more preferable, and a methyl group or an ethyl group is particularly preferable.

As the alkoxy group, for example, an alkoxy group having 1 to 18 carbon atoms is preferable, and an alkoxy group having 1 to 8 carbon atoms (for example, a methoxy group, an ethoxy group, n-butoxy group, and a methoxyethoxy group) is more Preferably, an alkoxy group having 1 to 4 carbon atoms is more preferable, and a methoxy group or an ethoxy group is particularly preferable.

As a halogen atom, a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom etc. are mentioned, for example, A fluorine atom or a chlorine atom is especially preferable.

Further, in the general formulas (Ar-1) to (Ar-5), Z ¹ , Z ² and Z ³ are each independently a hydrogen atom, a monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms, and 3 to 20 carbon atoms. represents a monovalent alicyclic hydrocarbon group, a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms, a halogen atom, a cyano group, a nitro group, -NR ⁶ R ⁷ , or -SR ⁸ , and R ⁶ to R ⁸ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms each independently, and Z ¹ and Z ² may combine with each other to form an aromatic ring.

As the monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms, an alkyl group having 1 to 15 carbon atoms is preferable, and an alkyl group having 1 to 8 carbon atoms is more preferable. A methyl group, an ethyl group, an isopropyl group, a tert-pentyl group (1,1 -dimethylpropyl group), tert-butyl group, or 1,1-dimethyl-3,3-dimethyl-butyl group is more preferred, and methyl group, ethyl group, or tert-butyl group is particularly preferred.

Examples of the monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclodecyl group, a methylcyclohexyl group, and monocyclic saturated hydrocarbon groups such as an ethylcyclohexyl group; Cyclobutenyl group, cyclopentenyl group, cyclohexenyl group, cycloheptenyl group, cyclooctenyl group, cyclodecenyl group, cyclopentadienyl group, cyclohexadienyl group, cyclooctadienyl group, and cyclodecadienyl group. a cyclic unsaturated hydrocarbon group; Bicyclo[2.2.1]heptyl group, bicyclo[2.2.2]octyl group, tricyclo[5.2.1.0 ^2,6 ]decyl group, tricyclo[3.3.1.1 ^3,7 ]decyl group, tetracyclo[6.2 polycyclic saturated hydrocarbon groups such as .1.1 ^3,6 .0 ^2,7 ]dodecyl group and adamantyl group; and the like.

Examples of the monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms include a phenyl group, a 2,6-diethylphenyl group, a naphthyl group, and a biphenyl group, and an aryl group having 6 to 12 carbon atoms (especially a phenyl group) desirable.

As a halogen atom, a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom etc. are mentioned, for example, A fluorine atom, a chlorine atom, or a bromine atom is especially preferable.

On the other hand, examples of an alkyl group having 1 to 6 carbon atoms represented by R ⁶ to R ⁸ include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, An n-pentyl group, an n-hexyl group, etc. are mentioned.

In the general formulas (Ar-2) and (Ar-3), A ³ and A ⁴ each independently consist of -O-, -N(R ⁹ )-, -S-, and -CO-. represents a group selected from the group, and R ⁹ represents a hydrogen atom or a substituent.

Examples of the substituent represented by R ⁹ include the same groups as the substituents Y ¹ in the general formula (Ar-1) may have.

Further, in the general formula (Ar-2), X represents a hydrogen atom or a nonmetal atom of Groups 14 to 16 to which a substituent may be bonded.

Moreover, examples of the nonmetal atoms of Groups 14 to 16 represented by X include an oxygen atom, a sulfur atom, a nitrogen atom having a substituent, and a carbon atom having a substituent, and examples of the substituent include an alkyl group and an alkoxy group. group, an alkyl-substituted alkoxy group, a cyclic alkyl group, an aryl group (for example, a phenyl group, a naphthyl group, etc.), a cyano group, an amino group, a nitro group, an alkylcarbonyl group, a sulfo group, and a hydroxyl group.

In Formula (Ar-3), L ⁷ and L ⁸ are each independently a single bond, -CO-O-, -C(=S)O-, -CR ¹ R ² -, -CR ¹ R ² -CR ³ R ⁴ -, -O-CR ¹ R ² -, -CR ¹ R ² -O-CR ³ R ⁴ -, -CO-O-CR ¹ R ² -, -O-CO-CR ¹ R ² -, -CR ¹ R ² -O-CO-CR ³ R ⁴ -, -CR ¹ R ² -CO-O-CR ³ R ⁴ -, -NR ¹ -CR ² R ³ -, or -CO- NR ¹ -. R ¹ , R ² , R ³ and R ⁴ each independently represent a hydrogen atom, a fluorine atom, or an alkyl group having 1 to 4 carbon atoms.

Further, in the general formula (Ar-3), SP ³ and SP ⁴ independently represent a single bond, a linear or branched alkylene group having 1 to 12 carbon atoms, or a linear or branched alkylene group having 1 to 12 carbon atoms. One or more of -CH ₂ - constituting the rene group represents a divalent linking group substituted with -O-, -S-, -NH-, -N(Q)-, or -CO-, and Q represents a substituent. . As a substituent, the same group as the substituent which Y ¹ in the said general formula (Ar-1) may have is mentioned.

Moreover, in the said general formula (Ar-3), P ^<3> and P ^<4> represent a monovalent organic group each independently, and a polymeric group is preferable. Examples of the polymerizable group are as described in relation to P ¹ and P ² described above. However, as described above, when MG is an aromatic ring represented by general formula (Ar-3), at least one of P ¹ and P ² and P ³ and P ⁴ in general formula (Ar-3) represents a polymerizable group.

Further, in the general formulas (Ar-4) to (Ar-5), Ax is an organic group having 2 to 30 carbon atoms and having at least one aromatic ring selected from the group consisting of aromatic hydrocarbon rings and aromatic heterocycles. indicate

Further, in the general formulas (Ar-4) to (Ar-5), Ay is selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 6 carbon atoms which may have a substituent, an aromatic hydrocarbon ring, and an aromatic heterocyclic ring. represents an organic group having 2 to 30 carbon atoms and having at least one aromatic ring.

Here, the aromatic rings in Ax and Ay may have a substituent, and Ax and Ay may combine to form a ring.

Moreover, Q ³ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms which may have a substituent.

Examples of Ax and Ay include groups described in paragraphs [0039] to [0095] of Patent Document 3 (International Publication No. 2014/010325).

Moreover, as a C1-C6 alkyl group which Q ^<3> represents, for example, a methyl group, an ethyl group, a propyl group, an isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pen A ethyl group, an n-hexyl group, etc. are mentioned, As a substituent, the same group as the substituent which Y ^<1> in the said general formula (Ar-1) may have is mentioned.

Preferred examples of the liquid crystal compound represented by the general formula (W) are shown below, but are not limited to these liquid crystal compounds. In addition, all 1, 4-cyclohexylene groups in the following formula are trans-1, 4-cyclohexylene groups. Moreover, in the following formula, n represents an integer of 1 to 12.

[Formula 3]

[Formula 4]

[Formula 5]

In the above formula, "*" represents a bonding position.

[Formula 6]

In addition, the group adjacent to the acryloyloxy group in the above formulas II-2-8 and II-2-9 represents a propylene group (a group in which a methyl group is substituted with an ethylene group), and represents a mixture of positional isomers with different positions of the methyl group .

[Formula 7]

[Formula 8]

[Formula 9]

[Formula 10]

[Formula 11]

[Formula 12]

The content of the polymerizable liquid crystal compound in the polymerizable liquid crystal composition is preferably 50 to 100% by mass, more preferably 60 to 98% by mass, and 65 to 95% by mass with respect to the total mass of the liquid crystal compound in the polymerizable liquid crystal composition. % is more preferred.

In addition, when the polymeric liquid crystal composition also contains a non-polymerizable liquid crystal compound, the total mass of the said liquid crystal compound is the mass also calculated.

When using 2 or more types of polymerizable liquid crystal compounds, the total content is preferably within the above range.

The content of the polymerizable liquid crystal compound in the polymerizable liquid crystal composition is preferably 50 to 99.99% by mass, more preferably 65 to 99.9% by mass, and 80 to 99.5% by mass with respect to the total solid mass of the polymerizable liquid crystal composition. is more preferable

When using 2 or more types of polymerizable liquid crystal compounds, the total content is preferably within the above range.

In addition, a total solid content intends the component which forms an optically anisotropic layer, and a solvent is not contained. In addition, as long as it is a component that forms an optically anisotropic layer, even if the property is a liquid, it is regarded as a solid component.

<Photoinitiator>

The polymerizable liquid crystal composition preferably contains a photopolymerization initiator.

The polymerization initiator used is preferably a photopolymerization initiator capable of initiating a polymerization reaction by ultraviolet irradiation.

As the photopolymerization initiator, for example, an oxime ester polymerization initiator, an α-carbonyl polymerization initiator (for example, US Patent Publication Nos. 2367661 and 2367670), an acyloinether polymerization initiator (for example, U.S. Patent Publication No. 2448828), α-hydrocarbon substituted aromatic acyloin-based polymerization initiators (eg, described in U.S. Patent Publication No. 2722512), polynuclear quinone-based polymerization initiators (eg, U.S. Patent Publication No. 3046127) , each description of No. 2951758), a polymerization initiator in which a triarylimidazole dimer and p-aminophenyl ketone are combined (for example, described in US Patent Publication No. 3549367), an acridine and phenazine-based polymerization initiator (for example, For example, Japanese Unexamined Patent Publication No. 60-105667, US Patent Publication No. 4239850), oxadiazole-based polymerization initiators (for example, described in US Patent Publication No. 4212970), and acylphosphine oxide-based polymerization initiators (eg For example, Japanese Patent Publication No. 63-040799, Japanese Patent Publication No. 5-029234, Japanese Unexamined Patent Publication No. Hei 10-095788, Japanese Unexamined Patent Publication No. Hei 10-029997), etc. are mentioned.

Among them, oxime ester-based polymerization initiators are preferable from the viewpoint that curing proceeds uniformly when exposed to light and an optically anisotropic layer more excellent in orientation is obtained.

The content of the photopolymerization initiator in the polymerizable liquid crystal composition is preferably 0.01 to 20% by mass, more preferably 0.1 to 8% by mass, based on the total mass of the polymerizable liquid crystal compound in the polymerizable liquid crystal composition.

A polymerization initiator may be used individually by 1 type, and may be used 2 or more types.

When using 2 or more types of polymerization initiators, the total content is preferably within the above range.

<Surfactant>

The polymerizable liquid crystal composition preferably contains a surfactant from the viewpoint of maintaining a smooth surface on the air interface side when an uncured layer is formed and obtaining an optically anisotropic layer with better orientation.

As such a surfactant, a fluorochemical surfactant or a silicon surfactant is preferable because of the high leveling effect with respect to the added amount, and a fluorochemical surfactant is more preferable from the viewpoint of less exudation (bloom, bleed).

Examples of surfactants include compounds described in paragraphs [0079] to [0102] of JP-A-2007-069471 and compounds represented by general formula (I) described in JP-A-2013-047204 (especially paragraph [0020]). ] to compounds described in [0032]), compounds represented by general formula (I) described in JP-A-2012-211306 (especially compounds described in paragraphs [0022] to [0029]), JP-A-2002-129162 A liquid crystal alignment accelerator represented by the general formula (I) described in No. (particularly, the compounds described in paragraphs [0076] to [0078] and paragraphs [0082] to [0084]), and the general formula described in Japanese Patent Laid-Open No. 2005-099248 Compounds represented by (I), (II) and (III) (especially the compounds described in paragraphs [0092] to [0096]) and the like.

<Solvent>

The polymerizable liquid crystal composition may contain a solvent in order to improve production aptitude such as lowering the viscosity at the time of formation of the uncured layer.

The solvent is not particularly limited, but is preferably selected from at least one of the group consisting of ketones (including cyclic ketones such as cyclopentanone), esters, ethers, alcohols, alkanes, toluene, chloroform, and methylene chloride and is more preferably selected from at least one member of the group consisting of ketones, esters, ethers, alcohols, and alkanes, and more preferably selected from at least one member of the group consisting of ketones, esters, ethers, and alcohols.

<Other ingredients>

The polymerizable liquid crystal compound may contain other components other than those described above.

As other components, a thermal polymerization initiator may be included, for example.

In addition, you may use a chiral agent etc. from the viewpoint of adjusting the orientation of an optically anisotropic layer, etc., for example.

In addition, from the viewpoint of adjusting the viscosity, phase transition temperature, and orientation uniformity of the polymerizable liquid crystal composition, film properties of the optically anisotropic layer, and adjusting optical properties, a non-polymerizable liquid crystal compound may be used. The non-polymerizable liquid crystal compound may be a low molecular liquid crystal compound. In addition, the non-polymerizable liquid crystal compound may be a main chain type liquid crystal polymer or a side chain type liquid crystal polymer.

You may use a polymerization inhibitor, an antioxidant, a ultraviolet absorber, etc. from a viewpoint of providing pot life of a polymeric liquid crystal composition, and improving durability of an optically anisotropic layer.

From the viewpoint of imparting additional functions, adjusting liquid properties, and adjusting film properties, etc., plasticizers, retardation regulators, dichroic dyes, fluorescent dyes, photochromic dyes, thermochromic dyes, photoisomerization materials, photodimerization materials , nanoparticles, and a thixotropic agent may be added.

The uncured layer formed using such a polymerizable liquid crystal composition preferably has a phase transition temperature of 80° C. or lower between the smectic phase and the nematic phase, for example, from the viewpoint of improving film contrast and panel contrast, 70° C. It is more preferable to be more than °C and less than 80 °C.

[Optical anisotropic layer]

Although the thickness of the optically anisotropic layer produced by the manufacturing method of this invention is not specifically limited, 0.1-10 micrometers are preferable, and 0.5-5 micrometers are more preferable.

The optically anisotropic layer produced by the production method of the present invention is preferably a layer in which a smectic phase is immobilized.

As a preferred embodiment of the optically anisotropic layer, a positive A plate can be cited. In order to obtain a positive A plate, there is a method of horizontally aligning a rod-shaped polymerizable liquid crystal compound. Further, when the in-plane retardation Re (550) is 100 to 160 nm (preferably 120 to 150 nm), it can be suitably used as a positive uniaxial λ/4 plate. In addition, Re (550) can be used as a positive uniaxial λ/2 plate in the range of 250 to 300 nm. Here, Re(550) represents the in-plane retardation of the optically anisotropic layer at a wavelength of 550 nm. The value of in-plane retardation can be measured using AxoScan OPMF-1 (manufactured by Opto Science Co., Ltd.).

As a suitable aspect other than the optically anisotropic layer, a positive C plate may be mentioned. In order to obtain a positive C plate, there is a method of vertically aligning rod-shaped polymerizable liquid crystal compounds. The thickness direction retardation Rth (550) is, for example, 20 to 200 nm, and is preferably 50 to 120 nm from the viewpoint of providing various optical compensation functions and/or viewing angle enhancement functions.

In addition, the optically anisotropic layer may be a negative A plate or a negative C plate.

In addition, in this specification, A plate is defined as follows.

There are two types of A plate, positive A plate (positive A plate) and negative A plate (negative A plate), and the refractive index in the slow axis direction within the film plane (the direction in which the refractive index within the plane becomes the maximum) is nx, When the refractive index in the direction perpendicular to the in-plane slow axis and the in-plane direction is ny and the refractive index in the thickness direction is nz, the positive A plate satisfies the relationship of equation (A1), and the negative A plate has the relationship of equation (A2) is to satisfy In addition, the positive A plate shows a positive Rth value, and the negative A plate shows a negative Rth value.

Equation (A1) nx>ny≒z

Equation (A2) ny<nx≒z

In addition, the said "≒" includes not only the case where both are completely the same, but also the case where both are substantially the same. "Substantially the same" means "ny≒nz" even when (ny-nz) x d (where d is the thickness of the film) is -10 to 10 nm, preferably -5 to 5 nm, for example. In addition, the case where (nx-nz) x d is -10 to 10 nm, preferably -5 to 5 nm is also included in "nx ≈ nz".

There are two types of C plate, a positive C plate (positive C plate) and a negative C plate (negative C plate). ) to satisfy the relationship. In addition, the positive C plate shows a negative Rth value, and the negative C plate shows a positive Rth value.

Equation (C1) nz>nx≒ny

Equation (C2) nz<nx≒ny

In addition, the said "≒" includes not only the case where both are completely the same, but also the case where both are substantially the same. “Substantially the same” also includes “nx≒ny” when (nx−ny)×d (where d is the thickness of the film) is 0 to 10 nm, preferably 0 to 5 nm, for example. .

In addition, the optical anisotropic wavelength dispersion can be appropriately adjusted by adjusting the type and usage amount of the polymerizable liquid crystal compound used in the polymerizable liquid crystal composition and other components.

Further, the optically anisotropic layer preferably exhibits reverse wavelength dispersion. For example, it is preferable that the optically anisotropic layer satisfy the relationship of the following formula (II).

Δn(450)/n(550)<1.00... (II)

Here, in Formula (II), Δn(450) represents the refractive index difference between the direction of the maximum refractive index in the optically anisotropic layer at a wavelength of 450 nm and the direction orthogonal thereto, and Δn(550) is the optically anisotropic layer at a wavelength of 550 nm Represents the difference in refractive index between the direction of maximum refractive index and the direction perpendicular thereto.

[Laminate]

As described above, the uncured layer may be disposed on a support or the like. That is, the optically anisotropic layer produced by the production method of the present invention may constitute a laminate together with layers other than the optically anisotropic layer.

<support>

There is no limitation in particular as a support body, Among them, a long polymer film is preferable from the point which enables continuous production.

Examples of the polymer film include polyolefin/cyclic olefin resins such as polypropylene and norbornene polymers; polyvinyl alcohol; polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polymethacrylic acid ester/polyacrylic acid ester such as polymethyl methacrylate; cellulose esters such as triacetyl cellulose, diacetyl cellulose, and cellulose acetate propionate; polyethylene naphthalate; Polycarbonate and a polymer film obtained by forming a film of these copolymers and the like are exemplified. These polymer films can be appropriately selected based on viewpoints such as tensile modulus, flexural modulus, parallel light transmittance, haze, optical anisotropy, optical isotropy, reverse peelability, and easy adhesiveness.

In the present invention, in order to obtain an optically anisotropic layer having a uniform orientation, in the case of forming an optically anisotropic layer by directly applying a polymerizable liquid crystal composition to a supporter, the surface of the supporter on the application side is preferably smooth, The surface roughness Ra is preferably 3 to 50 nm.

In addition, in using a long polymer film, in the state of a winding body in which the manufactured laminate is wound, from the point of preventing shape transfer and blocking phenomenon between the surfaces of the laminate, the polymerizable liquid crystal in the support An anti-blocking treatment or a mat treatment may be performed on the surface on the opposite side of the surface to which the composition is applied. Moreover, you may provide a knurling at the edge part of a laminated body.

Moreover, it is preferable that the support body can be peeled off. At this time, when the optically anisotropic layer is directly provided on the support, it is preferable that the support and the optically anisotropic layer can be separated from the interface. In addition, when an orientation layer and/or other layers (intermediate layers) described below are provided between the support and the optically anisotropic layer, it is preferable that the support and the optically anisotropic layer can be separated at any interface or within the layer. do.

<Alignment layer>

It is preferable to provide an orientation film on a support and further provide the above-mentioned optically anisotropic layer on the orientation film from the viewpoint of easiness to obtain an optically anisotropic layer having better orientation.

As the alignment film, various well-known alignment films can be used. For example, a rubbing film made of an organic compound such as a polymer (rubbing alignment film), an inorganic compound deposited in all directions, a film having microgrooves, and an organic compound (for example, ω - a film in which an LB film (Langmuir-Blodgett film) formed by the Langmuir-Blodgett method using trichosanoic acid, dioctadecylmethylammonium chloride, or methyl stearate, etc., is stacked; and the like.

A photo-alignment film is also preferable as the alignment film from the viewpoint of preventing alignment defects caused by foreign matter in advance.

As the rubbing alignment film, for example, polyimide, polyvinyl alcohol, a coating film such as a polymer having a polymerizable group described in JP-A-9-152509, JP-A-2005-097377, JP-A-2005- Orientation film of No. 099228, and Unexamined-Japanese-Patent No. 2005-128503, etc. are mentioned.

As a composition for forming a photo-alignment layer used in the photo-alignment layer that can be used in the present invention, there are descriptions in many literatures and the like. materials using an azo compound described in, for example, WO08/056597, Japanese Unexamined Patent Publication No. 2008-076839, and Japanese Unexamined Patent Publication No. 2009-109831; photo-alignment polyorganosiloxane composite materials described in Japanese Unexamined Patent Publication No. 2012-155308, Japanese Unexamined Patent Publication No. 2014-026261, Japanese Unexamined Patent Publication No. 2014-123091, and Japanese Unexamined Patent Publication No. 2015-026050; The cellulose ester material containing a cinnamic acid group of Unexamined-Japanese-Patent No. 2012-234146; Materials using the optical fleece dislocation reaction described in Unexamined-Japanese-Patent No. 2012-145660, and Unexamined-Japanese-Patent No. 2013-238717 or similar reactions thereof; Japanese Unexamined Patent Publication No. 2016-071286, Japanese Patent Publication No. 2013-518296, Japanese Patent Publication No. 2014-533376, Japanese Patent Publication No. 2016-535158, WO10/150748, WO11/126022, WO13/054784 , WO14/104320, and WO16/002722 for photodimerization-capable compounds (for example, cinnamate compounds, chalcone compounds, and/or coumarin compounds pendant materials in various polymers), etc., for forming photo-alignment films. can be used in the composition.

Among them, from the viewpoint of irradiation energy required for photo-alignment, orientation control force, etc., a photo-alignment film using a photoisomerization reaction of an azo group or a photo-alignment film using a photoreaction of a cinnamate compound is preferable.

The composition for forming an alignment film may contain a crosslinking agent, a binder, a plasticizer, a sensitizer, a crosslinking catalyst, an adhesion modifier, a leveling agent, and the like as needed.

The thickness of the alignment film is not particularly limited and can be appropriately selected according to the purpose, and is, for example, preferably 10 to 1000 nm, and more preferably 10 to 300 nm. The surface roughness of the alignment layer is as described above.

<Other floors (middle floors)>

The said layered product may further contain other layers as needed. For example, a smoothing layer, an easy adhesion layer, a reverse peeling layer, a light shielding layer, a coloring layer, a fluorescent layer, an oxygen barrier layer, and a water vapor barrier layer. A layer having one or more of the functions of such a layer is collectively referred to as an intermediate layer. The intermediate layer may be a layer having functions other than those described above.

An intermediate layer can be provided between the support and the optically anisotropic layer, and/or between the support and the above-mentioned alignment film, for example, to express various functions.

[Polarizer]

It is also preferable to use the optically anisotropic layer produced by the production method of the present invention by introducing it into a polarizing plate. In other words, it is also preferable that the laminate is a polarizing plate.

The said polarizing plate has at least the optically anisotropic layer manufactured by the manufacturing method of this invention, and a polarizer. The polarizing plate may be a circular polarizing plate.

<Polarizer>

The polarizer is not particularly limited as long as it is a member having a function of converting light into specific linearly polarized light, and conventionally known absorption-type polarizers and reflection-type polarizers can be used.

As the absorption type polarizer, an iodine-based polarizer, a dye-based polarizer using a dichroic dye, a polyene-based polarizer, and the like are used. An iodine-based polarizer and a dye-based polarizer include a coating type polarizer and a stretching type polarizer, and both can be applied, but a polarizer produced by adsorbing iodine or a dichroic dye to polyvinyl alcohol and stretching is preferable.

In addition, as a method of obtaining a polarizer by performing stretching and dyeing in the state of a laminated film in which a polyvinyl alcohol layer is formed on a substrate, Japanese Patent Publication No. 5048120, Japanese Patent Publication No. 5143918, Japanese Patent Publication No. 5048120, Japan Patent Publication No. 4691205, Japanese Patent Publication No. 4751481, Japanese Patent Publication No. 4751486, etc. are mentioned, and well-known techniques concerning these polarizers can also be used suitably.

As the reflective polarizer, a polarizer in which thin films having different birefringences are laminated, a wire-grid polarizer, a polarizer in which a cholesteric liquid crystal having a selective reflection region and a quarter-wave plate are combined, and the like are used.

Although the thickness of a polarizer is not specifically limited, 3-60 micrometers are preferable, 5-30 micrometers are more preferable, and 5-15 micrometers are more preferable.

<Optical anisotropic layer of polarizing plate>

It is preferable that the said polarizing plate has 2 or more types of optically anisotropic layers.

In this case, at least one of the two or more optically anisotropic layers of the polarizer may be an optically anisotropic layer produced by the production method of the present invention, and the other optically anisotropic layers are manufactured by a method other than the production method of the present invention. may be an optically anisotropic layer (also referred to as “other optically anisotropic layer”).

For example, it is preferable that the polarizing plate has a positive A plate and a positive C plate. In this case, the positive A plate is preferably an optically anisotropic layer manufactured by the manufacturing method of the present invention, and the positive C plate is preferably an optically anisotropic layer manufactured by the manufacturing method of the present invention or another optically anisotropic layer. .

Moreover, the polarizing plate which has the said positive A plate and positive C plate may further have another optically anisotropic layer.

In manufacturing a polarizing plate, you may arrange|position an optically anisotropic layer directly on a polarizer by apply|coating a polymeric liquid crystal composition on a polarizer, etc.

Moreover, for example, the polarizer and the optically anisotropic layer may be bonded through one or more other layers (adhesive layer or other optically anisotropic layer, etc.).

[Image display device]

The optically anisotropic layer produced by the manufacturing method of the present invention may be used for an image display device. The optically anisotropic layer may be used in the form introduced into the polarizing plate.

The display element used in the image display device is not particularly limited, and examples thereof include a liquid crystal cell, an organic electroluminescence (hereinafter abbreviated as "EL") panel, and a plasma display panel.

Among these, a liquid crystal cell or an organic EL display panel is preferable. That is, as the image display device, a liquid crystal display device using a liquid crystal cell as a display element or an organic EL display device using an organic EL panel as a display element is preferable.

<Liquid crystal display device>

The liquid crystal display device that is an example of the image display device is preferably a liquid crystal display device having, for example, the above-described polarizing plate and a liquid crystal cell.

As for a liquid crystal cell, VA (Virtical Alignment) mode, OCB (Optical Compensated Bend) mode, IPS (In-Place-Switching) mode, TN (Twisted Nematic), etc. are mentioned. Moreover, a method other than that may be sufficient. By combining an optical compensation structure and/or a luminance enhancement structure tailored to a liquid crystal cell by applying an optically anisotropic layer produced by the manufacturing method of the present invention, excellent wide viewing angle characteristics, light leakage prevention of black display, and high luminance display can be realized. can

In the image display device, among the polarizing plates provided on both sides of the liquid crystal cell, it is preferable to use the polarizing plate as the front-side polarizing plate, and more preferably to use the polarizing plate as the front-side and rear-side polarizing plates.

<Organic EL display device>

An organic EL display device, which is an example of an image display device, is preferably an organic EL display device including an organic EL display panel and a circularly polarizing plate disposed on the organic EL display panel. The circular polarizing plate used here is one type of the polarizing plate described above.

By having the circular polarizing plate, it is possible to suppress a phenomenon in which external light is reflected on the electrodes of the organic EL panel and thereby lower the display contrast, thereby enabling high-quality display.

A well-known structure can be used widely as an organic electroluminescent panel. Moreover, you may be provided with the touchscreen further.

Example

The present invention will be described in more detail below based on examples. The materials, usage amount, ratio, processing contents, processing procedures, etc. shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limitedly interpreted by the examples shown below.

[Example 1]

<Formation of photo-alignment layer>

(Production of Cellulose Acylate Film 1)

Production of core layer cellulose acylate dope

The following composition was put into a mixing tank, stirred, each component was dissolved, and a cellulose acetate solution used as a core layer cellulose acylate dope was prepared.

-------------------------------------------------- ---------------

Core layer cellulose acylate dope

-------------------------------------------------- ---------------

100 parts by mass of cellulose acetate having an acetyl substitution degree of 2.88

・In the embodiment of Japanese Unexamined Patent Publication No. 2015-227955

12 parts by mass of the described polyester compound B

2 parts by mass of the following compound G

・Methylene chloride (first solvent) 430 parts by mass

・Methanol (second solvent) 64 parts by mass

-------------------------------------------------- ---------------

compound G

[Formula 13]

･Production of outer layer cellulose acylate dope

10 parts by mass of the following mat agent solution was added to 90 parts by mass of the core layer cellulose acylate dope, and a cellulose acetate solution used as an outer layer cellulose acylate dope was prepared.

-------------------------------------------------- ---------------

mat solution

-------------------------------------------------- ---------------

Silica particles with an average particle size of 20 nm

(AEROSIL R972, Nippon Aerosil Co., Ltd.) 2 parts by mass

76 parts by mass of methylene chloride (first solvent)

11 parts by mass of methanol (second solvent)

1 part by mass of the above core layer cellulose acylate dope

-------------------------------------------------- ---------------

After filtering the core layer cellulose acylate dope and the outer layer cellulose acylate dope with a filter paper having an average pore size of 34 μm and a sintered metal filter having an average pore size of 10 μm, the core layer cellulose acylate dope and the outer layer cellulose acylates on both sides thereof Three layers of dope were simultaneously casted in a drum shape at 20°C from the casting process (band casting machine). It peeled off in the state of about 20 mass % of solvent content, fixed the both ends of the width direction of the film with tenter clips, and dried, extending|stretching at a draw ratio of 1.1 times in the transverse direction. Then, by conveying the obtained film between the rolls of a heat treatment apparatus, it further dried, produced the optical film of 40 micrometers in thickness, and made this the cellulose acylate film 1. The core layer of the cellulose acylate film 1 had a thickness of 36 µm, and the outer layers arranged on both sides of the core layer had a thickness of 2 µm, respectively. The in-plane retardation in the wavelength of 550 nm of the obtained cellulose acylate film 1 was 0 nm.

The obtained cellulose acylate film 1 was made into the temporary support body for formation.

(Manufacture of photo-alignment layer)

On the surface of cellulose acylate film 1, which is a temporary support for formation, the following coating liquid for forming an optical alignment film was applied with a #2 wire bar, and dried for 60 seconds with warm air at 60°C to prepare a coating film.

Using a 750 mW/cm ² ultra-high pressure mercury lamp (UL750, manufactured by HOYA CANDEO OPTRONICS Co., Ltd.), ultraviolet rays were vertically irradiated to the produced coating film in air. In addition, the illuminance of the ultraviolet rays was 5 mW/cm ² in the UV-A region (integration of wavelengths 320 to 380 nm), and the irradiation amount was 50 mJ/cm ² in the UV-A region.

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Coating solution for forming an optical alignment layer

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1 part by mass of the material for photo-alignment described below

16 parts by mass of water

42 parts by mass of butoxyethanol

42 parts by mass of propylene glycol monomethyl ether

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Materials for photo-alignment:

[Formula 14]

<Production of optically anisotropic layer A-1>

The following polymerizable liquid crystal composition A was applied to the surface of a slide glass, and the uncured layer formed from the polymerizable liquid crystal composition A was observed under a polarizing microscope while heating. As a result, the transition temperature of the isotropic (isotropic phase)-nematic phase (hereinafter also referred to as "TNI") at the time of temperature reduction of the uncured layer is 128 ° C., the phase transition temperature of the nematic phase-smectic phase (hereinafter referred to as "TNI"). TSmN") was 73°C. In addition, by maintaining the temperature at 50°C or lower, crystals were gradually generated. Moreover, TSmN at the time of temperature increase was 74 degreeC.

Further, from an X-ray diffraction (XRD) measurement, this smectic phase was a smectic A phase in which the layer structure and the liquid crystal compound were orthogonal and had no order in the layer.

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Polymeric liquid crystal composition A

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57.5 parts by mass of the following liquid crystal compound L-1

30 parts by mass of the following liquid crystal compound L-2

12.5 parts by mass of the following liquid crystal compound L-3

Photopolymerization initiator 1 (compound PI-1 below) 0.5 parts by mass

0.2 parts by mass of the following fluorine-containing compound F-1

Cyclopentanone 227.1 parts by mass

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[Formula 15]

Compound PI-1

[Formula 16]

The polymerizable liquid crystal composition A was applied on the photo-alignment layer using a spin coater to form an uncured layer (layer formation step). In addition, rotation speed was adjusted so that it might become desired thickness between 1000-5000 rpm.

Next, the uncured layer was heated to 80° C. (first heating temperature) using a hot plate to form a nematic phase, and maintained at that temperature for 10 seconds (first heating holding time) (nematic phase forming step).

Next, using a hot plate, the uncured layer was cooled from the first heating temperature to 65°C (cooling temperature) at a cooling rate of 40°C/min to form a smectic phase (cooling step).

Thereafter, the cooling holding time was set to 10 seconds and maintained at that temperature.

Next, the uncured layer at 65°C (cooling temperature) is irradiated with ultraviolet rays of 30 mJ/cm ² (integrated exposure amount with a wavelength of 300 to 390 nm) using an air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) in a nitrogen atmosphere. (1st exposure process), and it was set as the semi-hardened layer (1st polymerization process).

Subsequently, while maintaining in a nitrogen atmosphere, using a hot plate, the semi-cured layer was heated to 120 ° C. (second heating temperature) at an average heating rate of 100 ° C./min, and the air-cooled metal was heated while maintaining the second heating temperature. A halide lamp (manufactured by Eye Graphics Co., Ltd.) was further used, and ultraviolet rays of 500 mJ/cm ² (a cumulative dose of a wavelength of 300 to 390 nm) were irradiated (second exposure treatment) to fix the alignment state of the liquid crystal phase (second polymerization). process). Thus, a film A-1 (film 1) containing the temporary support for formation, the photo-alignment film, and the optically anisotropic layer A-1 was obtained.

The thickness of the formed optically anisotropic layer A-1 was 2.3 µm. In addition, the optical anisotropy of the formed optical anisotropic layer A-1 was measured using AxoScan OPMF-1 (manufactured by Opto Science), Re (550) was 144 nm, Rth (550) was 72 nm, Re (450) / Re ( 550) was 0.87.

[Examples 2 to 19, Comparative Examples 1 to 5 (production of optically anisotropic layers A-2 to A-24)]

Except for changing the conditions of each procedure as shown in Table 1 shown later, according to the production procedure of Film 1, films A-2 to A-24 (film 2) each containing optically anisotropic layers A-2 to A-24. ~24) was produced.

In Comparative Example 1, the first exposure treatment completed the preparation of the optically anisotropic layer.

In Comparative Example 2, exposure was performed immediately after the nematic phase formation step without passing through the cooling step, and preparation of the optically anisotropic layer was completed.

Table 1 shows the thickness, Re(550), Rth(550), and Re(450)/Re(550) of the obtained optically anisotropic layer.

[Comparative Example 6 (manufacture of optically anisotropic layer A-25)]

<Production of optically anisotropic layer>

The following polymerizable liquid crystal composition B was prepared. In addition, compound L-4 was synthesized according to the method of Unexamined-Japanese-Patent No. 2011-207765.

Next, the polymerizable liquid crystal composition B was applied to the surface of the slide glass, and the uncured layer formed from the polymerizable liquid crystal composition B was observed under a polarizing microscope while heating. As a result, when the temperature of the uncured layer was raised, a highly viscous intermediate phase was exhibited from 105°C to 137°C. Although it was difficult to determine the liquid crystal phase, a clear nematic liquid crystal phase was shown at 137°C or higher. The nematic liquid crystal phase existed up to 180°C or higher, and when the temperature fell, the nematic phase was exhibited and crystallized up to 61°C.

-------------------------------------------------- ---------------

Polymeric liquid crystal composition B

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29.1 parts by mass of the following liquid crystal compound L-4

Photopolymerization initiator 1 (Irgacure 819, manufactured by BASF) 0.87 parts by mass

0.02 parts by mass of the above fluorine-containing compound F-1

70 parts by mass of cyclopentanone

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(liquid crystal compound L-4)

[Formula 17]

The polymerizable liquid crystal composition B was applied on the photo-alignment layer using a spin coater to form an uncured layer (layer formation step).

Film A-25 (Film 25) containing the optically anisotropic layer A-25 according to the production procedure of Film 1, except that the conditions of each procedure were changed as shown in Table 1 shown later using the obtained uncured layer. has produced

Table 1 shows the thickness, Re(550), Rth(550), and Re(450)/Re(550) of the obtained optically anisotropic layer.

[Production of positive C plate]

In the same manner as the positive C plate described in paragraph [0124] of Japanese Laid-open Patent Publication No. 2015-200861, the transfer film C1 having the positive C plate C-1 provided on the temporary support for formation, and the positive C provided on the temporary support for formation. A transfer film C2 having plate C-2 was produced. The phase difference was measured using AxoScan OPMF-1 (manufactured by Opto Science). Positive C plate C-1 had Re (550) = 0 nm and Rth (550) = -112 nm, and positive C plate C-2 had Re (550 nm). ) = 0 nm, Rth (550) = -69 nm. The phase difference values of the positive C plate C-1 and the positive C plate C-2 were adjusted by adjusting the thickness.

[Production of polarizing plate]

The surface of TD80UL (manufactured by Fujifilm Corporation) as a support was subjected to alkali saponification treatment. Specifically, the support was immersed in a 1.5N sodium hydroxide aqueous solution at 55°C for 2 minutes, and the taken out support was washed in a room temperature water bath and neutralized at 30°C using 0.1N sulfuric acid. Thereafter, the obtained support was washed again in a water washing bath at room temperature, and further dried with warm air at 100°C.

Subsequently, the roll-shaped polyvinyl alcohol film with a thickness of 80 μm was continuously stretched 5 times in an iodine aqueous solution, and the film after stretching was dried to obtain a polarizer with a thickness of 20 μm.

The obtained polarizer and the alkali saponification treated support (TD80UL) were bonded together to obtain a polarizing plate 0 in which the polarizer was exposed on one side.

Next, polarizing plate 0 and film 1 were bonded together using an adhesive so that the polarizer of the polarizing plate 0 and the optically anisotropic layer A-1 faced each other. At this time, the absorption axis of the polarizer and the slow axis of the optically anisotropic layer A-1 were orthogonal.

Then, from the bonded film 1, the temporary support for formation and the photo-alignment film were peeled off, and only the optically anisotropic layer A-1 was transferred onto the polarizing plate.

Further, transfer film 1 was bonded on the optically anisotropic layer with an adhesive so that the optically anisotropic layer A-1 and the positive C plate C-1 faced each other. Then, the temporary support for formation was peeled off from the bonded transfer film 1, and the polarizing plate P-1 in which the support/polarizer/adhesive/optically anisotropic layer/adhesive/positive C plate C-1 was laminated in this order was obtained.

Instead of Film 1, using Films 2 to 25 each containing optically anisotropic layers A-2 to A-25, polarizers P-2 to P-25 were obtained according to the same procedure as above.

[Production of liquid crystal display device]

The polarizing plate on the viewing side was peeled off from the liquid crystal cell of iPad (registered trademark, manufactured by Apple Inc.), and used as a liquid crystal cell in IPS mode.

Instead of the peeled polarizing plate, the polarizing plates P-1 to P-25 produced above were bonded together to the liquid crystal cell to produce a liquid crystal display device.

At this time, when observed in a direction perpendicular to the liquid crystal cell substrate surface, the absorption axis of the polarizer in each of the polarizing plates P-1 to P-25 and the optical axis of the liquid crystal layer in the liquid crystal cell were bonded in a direction perpendicular to the direction.

〔evaluation〕

For the measurement of display performance, a commercially available liquid crystal viewing angle and chromaticity characteristic measuring apparatus Ezcontrast (manufactured by ELDIM) was used, and the liquid crystal display device produced above was used. Moreover, in the produced liquid crystal display device, the liquid crystal cell to which the polarizing plate produced above was bonded was installed and measured so that an optically anisotropic layer might become the side opposite to the backlight side. The results are shown in Table 1 below.

<Panel Contrast>

The average value (luminance max) of the maximum values of each black luminance (Cd/m ² ) in the upward direction (azimuth angle 0 to 175°, 5° increments) and downward direction (azimuth angle 180 to 355°, 5° increments) was obtained. . The smaller the value of the luminance max, the smaller the light leakage of the black display and the better the panel contrast, and evaluated in two stages of A and B below.

A: 0.70 or less

B: greater than 0.70

<Film Contrast>

On the table, in order from the bottom, a direct fluorescent tube backlight source, an upper polarizer, a sample (any one of the films A-1 to A-25 prepared above), and a lower polarizer were placed so that each surface was level. At this time, the sample and the upper polarizing plate were rotatable. The luminance of the light emitted from the light source and sequentially passed through the upper polarizer, the sample, and the lower polarizer was measured in the vertical direction using a luminance meter (eg BM-5A (manufactured by TOPCON)). In addition, the polarization degree of 99.995% or more was used for the upper polarizing plate and the lower polarizing plate, respectively.

In the measurement, first, the upper polarizer was rotated in the absence of the sample to adjust the position to the darkest luminance (cross Nicols state).

After inserting the sample, the sample was rotated under crossed Nicols to measure the minimum luminance. Next, the two polarizing plates, the upper polarizing plate and the lower polarizing plate, were set in a parallel Nicol arrangement, and the sample was rotated to measure the maximum luminance.

In order to eliminate the contribution of the luminance leakage due to the upper polarizer and the lower polarizer, a value obtained by the following formula is defined as the contrast of the film. The results are shown in Table 1 below.

Contrast = 1/[{(minimum luminance under crossed nicols when the sample is placed)/(maximum luminance under parallel nicols when the sample is placed)}-{(minimum luminance under crossed nicols when no sample is present) )/(Maximum luminance under parallel Nicols in the absence of sample)}]

Based on the value of the calculated contrast, the film contrast was evaluated in light of the following criteria. In addition, the higher the value of the contrast, the better the film contrast.

A: Contrast is over 100,000

B: Contrast is 70,000 or more and less than 100,000

C: Contrast between 40,000 and 70,000

D: Contrast less than 40,000

<Durability of optically anisotropic layer>

Film 1 was bonded together on the glass plate using the adhesive. Then, the temporary support for formation and the photo-orientation film were peeled off from the bonded film 1, and a laminate was obtained in the order of glass plate/adhesive/optically anisotropic layer. The optical anisotropy of this laminate was quantified using AxoScan OPMF-1 (manufactured by Opto Science) (Re(550)a). Further, after passing the same layered product under 80°C drying conditions for 500 hours, the optical anisotropy was quantified in the same manner as before the passage (Re(550)b). The phase difference change rate calculated from the following formula was evaluated according to the following evaluation criteria A to C. The results are shown in Table 1.

(rate of phase difference change) =|Re(550)a-Re(550)b|÷Re(550)a

A: phase difference change rate is 0.02 or less

B: phase difference change rate is larger than 0.02 and smaller than 0.04

C: phase difference change rate is 0.04 or more

The results are shown in Table 1.

In Table 1, the column of "rising temperature range" shows the difference in temperature of the semi-cured layer before and after the second heat treatment.

The column "Temperature difference between TSmN during temperature rise" shows the temperature difference between the first heating temperature and TSmN during temperature rise of the uncured layer.

The column "Temperature difference of TSmN during temperature decrease" shows the temperature difference between the cooling temperature and TSmN during temperature decrease of the uncured layer.

[Table 1]

From the results shown in Table 1, it was confirmed that according to the manufacturing method of the present invention, an optically anisotropic layer having excellent durability and film contrast, and capable of producing an image display device with excellent panel contrast was obtained.

Among them, when the exposure amount in the first exposure treatment was 10 mJ/cm ² or more, it was confirmed that the film contrast of the optically anisotropic layer was more excellent (comparison between Examples 9 and 10).

When the exposure amount in the first exposure treatment was 30 mJ/cm ² or less, it was confirmed that the durability of the optically anisotropic layer was more excellent (comparison of Examples 1, 11, and 12).

When the cooling rate in the cooling step was 80°C/min or less (more preferably 60°C/min or less), it was confirmed that the optically anisotropic layer had better film contrast (comparison of Examples 17 to 19).

When the difference between the temperature of the uncured layer during the first exposure treatment and the temperature of the semi-cured layer during the second exposure treatment was 40 ° C. or more, it was confirmed that the durability of the optically anisotropic layer was more excellent (comparison between Examples 1 and 3). ).

When the exposure amount in the second exposure treatment was 200 mJ/cm ² or more, it was confirmed that the durability of the optically anisotropic layer was more excellent (comparison between Examples 6 and 7).

[Examples 101 and 102]

[Production of circular polarizing plate with positive C plate]

The surface of the polarizer of the polarizer 0 and the optically anisotropic layer of the film 1 prepared above is coated with an adhesive so that the absorption axis of the polarizer of the prepared polarizer 0 and the slow axis of the optically anisotropic layer intersect at 45°. so it was conjoined. Subsequently, the temporary support for formation and the photo-alignment film were peeled from the bonded film 1, and only the optically anisotropic layer was transferred onto the polarizing plate 0.

Further, the surface of the positive C plate C-2 is bonded onto the surface of the above-described optically anisotropic layer using an adhesive, and then the temporary support for formation is peeled off from the polarizing plate, and the support/polarizer/adhesive/optically anisotropic layer/ A circularly polarizing plate CP-1 was obtained in which the pressure-sensitive adhesive/positive C plate C-2 was laminated in this order.

[Production of organic EL display device]

SAMSUNG GALAXY S IV (organic EL display device) equipped with an organic EL display panel was disassembled, the circular polarizing plate was peeled off, and the circular polarizing plate CP-1 was bonded onto the organic EL display panel, respectively, to prepare an organic EL display device. .

〔evaluation〕

<Reflection Color>

Using the organic EL display device before disassembly and the organic EL display device changed to each circular polarizing plate, the reflection color tone of the panel during black display under natural light was observed by viewing from the front and the polar angle direction of 45°, and evaluated based on the following criteria. did.

A: Compared to the organic EL panel before decomposition, the reflective color tone is equal to or close to neutral black.

B: Compared to the organic EL panel before disassembly, inclusion of color is seen

The results are shown in Table 2.

The column of "frontal reflection" in the table shows the evaluation result of the reflection color tone when observed by visual recognition from the front.

The column "45° reflection" shows the evaluation result of reflection color tone when observed by a viewer in the direction of the polar angle 45°.

[Table 2]

From the results shown in Table 2, it was confirmed that the optically anisotropic layer obtained by the production method of the present invention can be suitably used also in an organic EL display device.

Claims (12)

Step A of forming an optical alignment film on a support and forming an uncured layer containing a polymerizable liquid crystal compound having reverse wavelength dispersion on the optical alignment film;
Step B of subjecting the uncured layer to heat treatment to form a nematic phase;
Step C of forming a smectic phase by subjecting the uncured layer in which the nematic phase is formed to a cooling treatment;
Step D of forming a semi-cured layer by subjecting the uncured layer in which the smectic phase is formed to a first exposure process;
Heat treatment is performed so as to be a temperature condition higher than the temperature during the first exposure treatment, and after the heat treatment, a second exposure treatment is performed on the semi-cured layer under a temperature condition higher than the temperature during the first exposure treatment, , A method for producing an optically anisotropic layer having a step E of forming the optically anisotropic layer. The method of claim 1,
In the step E, without performing exposure treatment, heat treatment is performed so as to be a temperature condition higher than the temperature at the time of the first exposure treatment, and after the heat treatment, under a temperature condition higher than the temperature at the time of the first exposure treatment A method for producing an optically anisotropic layer, which is a step of forming an optically anisotropic layer by subjecting the semi-cured layer to a second exposure process. The method of claim 1,
The manufacturing method of the optically anisotropic layer, wherein the cooling rate of the uncured layer in the step C is 1 to 100°C/min. The method according to any one of claims 1 to 3,
The manufacturing method of the optically anisotropic layer, wherein the cooling rate of the uncured layer in the step C is 1 to 60°C/min. The method according to any one of claims 1 to 3,
The method for producing an optically anisotropic layer in which the temperature of the uncured layer gradually decreases in the step C. The method according to any one of claims 1 to 3,
The method for producing an optically anisotropic layer, wherein the light used in the first exposure treatment is an ultraviolet ray. The method according to any one of claims 1 to 3,
The method for producing an optically anisotropic layer, wherein the exposure amount in the first exposure treatment is 1 to 60 mJ/cm ² . The method according to any one of claims 1 to 3,
The method for producing an optically anisotropic layer, wherein the exposure amount in the first exposure treatment is 10 to 30 mJ/cm ² . The method according to any one of claims 1 to 3,
A method for producing an optically anisotropic layer wherein a temperature during the second exposure treatment is higher than a phase transition temperature between a smectic phase and a nematic phase of the polymerizable liquid crystal compound. The method according to any one of claims 1 to 3,
The manufacturing method of the optically anisotropic layer, wherein the difference between the temperature during the first exposure process and the temperature during the second exposure process is 20°C or higher. The method according to any one of claims 1 to 3,
The method for producing an optically anisotropic layer, wherein a difference between a temperature during the first exposure process and a temperature during the second exposure process is 40°C or higher. The method according to any one of claims 1 to 3,
The manufacturing method of the optically anisotropic layer in which the said uncured layer contains an oxime ester type polymerization initiator.