WO2019098215A1 - Long liquid crystal film, long polarizing film, image display device, and method for producing long liquid crystal film - Google Patents

Abstract

Provided is a liquid crystal film with minimal in-plane unevenness in front color when incorporated into a display device, and with minimal individual differences in front color. Also provided are a long polarizing film, an image display device, and a method for producing a long liquid crystal film. The long liquid crystal film comprises at least: a long substrate, and a long liquid crystal layer having an in-plane phase difference. The long substrate has, in the longitudinal direction thereof, a plurality of band-shaped thickness variation regions which extend in the width direction. The liquid crystal layer has, at a position in the thickness unevenness region in the planar direction, a band-shaped in-plane phase difference unevenness region which extends in the width direction of the long substrate, and the phase difference gradient of the in-plane phase difference unevenness region falls within the range of 0.002 to 0.018 (nm/mm).

Description

Long liquid crystal film, long polarizing plate, image display device, and method of manufacturing long liquid crystal film

The present invention relates to a liquid crystal film, a long polarizing plate, an image display device, and a method of manufacturing a long liquid crystal film.

Conventionally, a liquid crystal film having a liquid crystal layer formed using a polymerizable liquid crystal compound is used as a retardation film or a high function film. In such a liquid crystal film, for example, an alignment layer is provided on a support, and a composition containing a polymerizable liquid crystal compound is coated on the alignment layer, and the polymerizable liquid crystal compound aligned by the alignment control force of the alignment layer By polymerizing to fix the orientation state. At that time, by adjusting the alignment state of the polymerizable liquid crystal compound, it is possible to obtain a liquid crystal film having a liquid crystal layer having desired optical properties.
For example, Patent Document 1 describes that a layer in which a liquid crystal compound is given a predetermined orientation is formed to form an optically anisotropic layer.

In addition, in order to obtain a liquid crystal film with few defects, as described in Patent Document 2, using a photoalignment layer instead of the rubbing alignment layer conventionally used has been proposed. In the case of using a photoalignment layer, the process of applying an alignment regulating force to the alignment layer can be performed without contact. Therefore, it is possible to suppress unevenness and defects caused by foreign matter associated with rubbing.

By the way, as a display apparatus to which a liquid crystal film is applied, a liquid crystal display apparatus and an organic electroluminescent display apparatus are mentioned, for example. In these display devices, high definition and high dynamic range are continuously performed, pixel pitch is finer, white luminance is higher, and black display performance is continuously demanded.

Along with the enhancement of the performance of such display devices, the influence on the display quality of the display devices exerted by the phase difference unevenness caused by various factors in addition to the defects caused by the foreign matter in the liquid crystal film is becoming non-negligible. Therefore, various methods for suppressing the retardation unevenness of the liquid crystal film have been proposed.

For example, in Patent Document 3, in a heat treatment method of a coated film in which a coating film formed by applying a coating solution to a traveling long support is heat-treated, hot air is applied to the coating film surface of the traveling long support By blowing hot air on at least one side upstream or downstream of the same surface that has been blown, thereby generating an air flow along the running direction of the long support, and The heat treatment method of the coating film which makes the wind velocity of the width direction 1 m / s or less is described. It is described that the heat processing nonuniformity does not generate | occur | produce in the heat processing of a coating film by this, and the orientation-axis shift | offset | difference (dispersion | variation) of a liquid crystal layer can be prevented.

Further, Patent Document 4 includes a step of applying a coating solution containing a liquid crystalline compound on a transparent belt-shaped film on which an alignment film layer is formed, drying the applied layer, and curing the dried applied layer. In the method for producing an optical compensation film, the steps from drying to a solid content concentration in the coating layer of 80% or more to completion of curing of the coating layer are the steps of: The manufacturing method of the optical compensation film which makes the wind speed of the dry wind component of the width direction 0.7 m / s or less is described. It is described that by this, the disorder of the alignment state of the liquid crystal compound due to the drying wind is suppressed to reduce the deviation and the variation of the slow axis.

JP-A-8-94838 Japanese Patent Laid-Open No. 2000-86786 JP 2001-314799 A JP 2008-224968 A

By the way, according to the study of the present inventors, in particular, in the case of a small electronic device such as a smartphone, since the distance between the user and the display device becomes closer, in-plane unevenness of front color within the screen It turned out that there is a problem that it becomes easy to be recognized visually.
In addition, liquid crystal films are conventionally produced in large areas and cut out according to the size of individual display devices, but there are individual differences in frontal color even when cut out from the same liquid crystal film . In particular, in the case of a small electronic device such as a smartphone, there is a problem that individual differences are easily recognized.

The object of the present invention is to solve the above-mentioned problems of the prior art, to reduce the in-plane unevenness of the front color when incorporated in a display device, and to provide a long liquid crystal film with small individual differences in front color. It is providing a polarizing plate, an image display apparatus, and the manufacturing method of a long liquid crystal film.

As a result of addressing the above-mentioned problems, the inventors have found that the problems can be solved by the following configuration. That is, the present invention is as follows.

[1] A long liquid crystal film comprising at least a long base material and a long liquid crystal layer having in-plane retardation,
The long base material has a plurality of strip-like thickness unevenness regions extending in the width direction in the longitudinal direction,
The liquid crystal layer has a band-like in-plane retardation unevenness area extending in the width direction of the long base material at the position of the thickness unevenness area in the plane direction,
A long liquid crystal film characterized in that the retardation inclination ΔRe of the in-plane retardation unevenness region is in the range of 0.002 to 0.018 (nm / mm).
[2] The film thickness gradient ΔT of the elongated substrate is in the range of 0.005 to 0.025 (μm / mm) within the strip-shaped uneven thickness region extending in the width direction of the elongated substrate [ The long liquid crystal film as described in 1].
[3] The long liquid crystal film according to [1] or [2], which comprises a long light alignment layer between the long base material and the long liquid crystal layer.
[4] The long liquid crystal film according to [3], wherein the liquid crystal layer is provided so as to be peelable between the photoalignment layer and the liquid crystal layer, or between the long base and the photoalignment layer.
[5] The length according to any one of [1] to [4], wherein the liquid crystal layer is a λ / 4 wavelength plate, and the slow axis thereof forms 45 ° with the longitudinal direction of the long base material. Measure liquid crystal film.
[6] The long liquid crystal film according to any one of [1] to [5], wherein the liquid crystal layer satisfies the following formula.
Re (450) <Re (550) <Re (650)
0.03 <Δn (550) <0.20
[7] The long liquid crystal film according to any one of [1] to [6], wherein the in-plane retardation Re of the long base is 5 nm or less.
[8] The long liquid crystal film according to any one of [1] to [7],
A long polarizing plate having a long linear polarizer laminated on a long liquid crystal film.
[9] An image display device including the polarizing plate cut out from the long polarizing plate described in [8].
[10] A method for producing a long liquid crystal film, wherein a long liquid crystal layer is provided on a long base material,
Preparing a long base roll having a plurality of streaky uneven thickness regions extending in the width direction in the longitudinal direction;
While feeding the long base material from the long base material roll and conveying it in the longitudinal direction, sequentially
An orientation step of applying an orientation regulating force to a long substrate in a long shape,
A step of applying the polymerizable liquid crystal composition in the form of a long on the region of the long substrate to which the alignment control force is applied,
After a coating liquid layer formed by coating is subjected to alignment treatment, it is cured to fix the alignment state, and a liquid crystal layer forming step of forming a liquid crystal layer,
And winding the long liquid crystal film, in which the liquid crystal layer and the long base material are laminated, in a roll.
In the coating step, a means for adjusting the thickness of the coating liquid layer laminated on the long base material to a constant level is taken, and the variation of the thickness of the liquid crystal layer is made within ± 2% of the average thickness. A method of producing a long liquid crystal film characterized by the above.
[11] The method for producing a long liquid crystal film according to [10], wherein the in-plane retardation Re of the long base is 5 nm or less.

According to the present invention, a long liquid crystal film, a long polarizing plate, an image display device, and the like, with less in-plane unevenness of front color when incorporated into a display device and small individual differences in front color. It is possible to provide a method of manufacturing a liquid crystal film.

It is sectional drawing which shows the elongate liquid crystal film of this invention typically. It is a perspective view which shows the elongate liquid crystal film of this invention typically. It is a schematic diagram of an example of the manufacturing apparatus which enforces the manufacturing method of the elongate liquid crystal film of this invention. It is sectional drawing which shows typically the elongate polarizing plate which has a liquid crystal film of this invention. It is an example of the manufacturing apparatus which manufactures the elongate polarizing plate of this invention. It is sectional drawing which shows typically an example of the image display apparatus of this invention.

Hereinafter, embodiments of the present invention will be described in detail. In the present specification, a numerical range represented using “to” means a range including the numerical values described before and after it as the lower limit value and the upper limit value.
In addition, “orthogonal” and “parallel” in terms of angles shall mean the range of strict angles ± 10 °, and “identical” and “different” in angles may be whether the difference is less than 5 ° It can be judged on the basis of
Also, in the present specification, “visible light” refers to 380 to 780 nm. Moreover, in the present specification, the measurement wavelength is 550 nm unless otherwise specified.
Next, terms used in the present specification will be described.

<Late axis>
In the present specification, the “slow axis” means the direction in which the refractive index is maximum in the plane. In addition, when calling it the slow axis of retardation film, the slow axis of the whole retardation film is intended.

<Re (λ), Rth (λ)>
The values of in-plane retardation and retardation in the thickness direction refer to values measured using light of a measurement wavelength using AxoScan OPMF-1 (manufactured by Opt-Science Co., Ltd.).
Specifically, by inputting the average refractive index ((Nx + Ny + Nz) / 3) and the film thickness (d (μm)) with AxoScan OPMF-1
Slow axis direction (°)
Re (λ) = R0 (λ)
Rth (λ) = ((nx + ny) / 2-nz) × d
Is calculated.
Although R0 (λ) is displayed as a numerical value calculated by AxoScan OPMF-1, it means Re (λ).

[Long liquid crystal film]
The long liquid crystal film of the present invention is
A long liquid crystal film comprising at least a long base material and a long liquid crystal layer having in-plane retardation,
The long base material has a plurality of strip-like thickness unevenness regions extending in the width direction in the longitudinal direction,
The liquid crystal layer has a band-like in-plane retardation unevenness area extending in the width direction of the long base material at the position of the thickness unevenness area,
It is a long liquid crystal film in which the retardation slope ΔRe of the in-plane retardation unevenness region is in the range of 0.002 to 0.018 (nm / mm).
In the long liquid crystal film of the present invention, as a preferable configuration, the film thickness gradient ΔT of the long substrate in the band-like thickness unevenness area extending in the width direction of the long substrate is 0.005 to 0. It is in the range of 025 (μm / mm).
The long liquid crystal film of the present invention preferably includes a long light alignment layer between the long base material and the long liquid crystal layer.

The long liquid crystal film will be described in detail below. In addition, about physical-property values, such as retardation value and thickness which are mentioned later, shall be in the part (Typically, center area | region of the width direction with respect to the width direction) used for subsequent use.

FIG. 1 is a cross-sectional view schematically showing a long liquid crystal film of the present invention. FIG. 1 is a cross-sectional view in the direction perpendicular to the longitudinal direction of the long liquid crystal film. FIG. 2 is a perspective view schematically showing a long liquid crystal film of the present invention. The illustration of the alignment layer 2 is omitted in FIG.
The long liquid crystal film 10 shown in FIG. 1 has a long base 1 (a long base, hereinafter, also simply referred to as a base) 1, a long alignment layer 2, and a long liquid crystal layer 3 It has the structure laminated | stacked in this order.
In addition, in FIG. 1, although the elongate base material 1, the alignment layer 2, and the liquid crystal layer 3 are drawn in equal width, in the actual manufacture, the elongate base material 1 is wider than the alignment layer 2, The liquid crystal layer 3 is generally provided narrower than the alignment layer 2. However, if necessary, the liquid crystal layer 3 may be wider than the alignment layer 2 and may be narrower than the long base material 1.
In the following description, the direction in which the long liquid crystal film extends is taken as the longitudinal direction, and the direction orthogonal to the longitudinal direction is taken as the width direction.

Here, the elongated liquid crystal film of the present invention has a strip-shaped uneven thickness region 5 in which the elongated substrate 1 extends in the width direction, and the liquid crystal layer 3 extends in the width direction at the position of the uneven thickness region in the surface direction. There is a strip-shaped in-plane retardation unevenness region 6 extending, and the retardation inclination ΔRe of the in-plane retardation unevenness region is in the range of 0.002 to 0.018 (nm / mm).
The above-mentioned range of the phase difference inclination ΔRe means that the variation of the phase difference in the plane is gentle.

As described above, in the case of a small electronic device such as a smartphone, it is understood that the distance between the user and the display device is closer, so that there is a problem that the front color unevenness in the screen is easily visible. The
In addition, liquid crystal films are conventionally produced in large areas and cut out according to the size of individual display devices, but there are individual differences in frontal color even when cut out from the same liquid crystal film . In particular, in the case of a small electronic device such as a smartphone, there is a problem that individual differences are easily recognized.

According to the study of the present inventors, it was found that when viewed as a display device, the front color taste unevenness occurs in the screen because the liquid crystal film has a variation in retardation in the plane.
Generally, a liquid crystal film is produced by forming a liquid crystal layer on a long base material by roll-to-roll. According to the study of the present inventors, it was found that the thickness of the long base material fluctuates in the longitudinal direction due to its manufacturing process, and thickness unevenness is present. Therefore, the thickness of the liquid crystal layer formed on the elongated base also varies in the longitudinal direction due to the uneven thickness of the elongated base. As well known, the in-plane retardation of the liquid crystal layer is determined by the refractive index anisotropy Δn of the liquid crystal material and the orientation and the film thickness of the liquid crystal layer. Therefore, the in-plane retardation Re of the liquid crystal layer fluctuates due to the fluctuation of the thickness of the liquid crystal layer. As a result, in the display device having a liquid crystal film, front color unevenness occurs in the screen.

On the other hand, in the long liquid crystal film 10 of the present invention, the retardation inclination ΔRe of the in-plane retardation unevenness region 6 is in the range of 0.002 to 0.018 (nm / mm), that is, in the plane. It makes the fluctuation of the phase difference smooth. As a result, in the display device having the liquid crystal film cut out from the long liquid crystal film 10 of the present invention, it is possible to suppress the occurrence of color change due to front color unevenness in the screen.
Further, by making the fluctuation of the retardation in the plane smooth, it is possible to suppress the individual difference in the frontal color unevenness when a plurality of liquid crystal films are cut out from the long liquid crystal film.

Here, the in-plane retardation unevenness area 6 is defined as an area having a difference of 0.2 nm or more from the average value of the in-plane retardation (Re (550)) of the liquid crystal layer 3. The average value of the in-plane retardation is obtained by measuring the in-plane retardation of the liquid crystal film cut out by 1 m in the longitudinal direction of the long base material at 500 points every 2 mm and taking the average value.

The phase difference slope ΔRe is
ΔRe = (maximum value of in-plane retardation variation [nm]) ÷ (average of longitudinal length of in-plane retardation unevenness region [mm])
Determined by
Here, the maximum value of the in-plane retardation variation is the maximum retardation value in the linear region extending in the longitudinal direction of the long base material in the region where the average value of the in-plane retardation is measured, and the average It is the difference with the value.
Further, as the length in the longitudinal direction of the in-plane retardation unevenness region, a value obtained by averaging five points in the width direction with respect to one in-plane retardation unevenness region is used.

In the display device, the retardation slope ΔRe is preferably 0.002 to 0.015 (nm / mm) from the viewpoint of suppressing generation of in-plane front color unevenness and suppressing individual differences in front color. Preferably, 0.002 to 0.0010 (nm / mm) is more preferable.

The method of forming the liquid crystal layer having a small retardation inclination ΔRe as described above will be described in detail later.

Moreover, with the thickness nonuniformity area | region 5 of the elongate base material 1, the thickness defines it as an area | region which has an average thickness and a difference of 0.1 micrometer or more. In FIG. 2, the position of the average thickness is indicated by an alternate long and short dash line Lave. Moreover, the area | region which has a difference of 0.1 micrometer or more in thickness with respect to average thickness is shown by hatching. An area indicated by hatching is the uneven thickness area 5. As shown in FIG. 2, the elongated base material has a plurality of thickness unevenness regions in the longitudinal direction, and each thickness unevenness region extends in the width direction.
Average thickness measures the thickness of the elongate base material of the liquid-crystal film cut out by 1 m in the longitudinal direction of an elongate base material 500 points every 2 mm, and makes it the average value.

As described above, the in-plane retardation unevenness region 6 is generated due to the fluctuation of the thickness of the liquid crystal layer 3. Therefore, as shown in FIG. 2, in the plane direction, the position of the in-plane retardation unevenness region 6 and the position of the thickness unevenness region 5 substantially coincide with each other. The length in the longitudinal direction of the in-plane retardation unevenness area 6 and the length in the longitudinal direction of the thickness unevenness area 5 do not necessarily coincide with each other.

Here, the film thickness gradient ΔT of the elongated base material 1 in the band-like thickness unevenness region 5 extending in the width direction of the elongated base material 1 is in the range of 0.005 to 0.025 (μm / mm). And the range of 0.010 to 0.020 (μm / mm) is more preferable, and the range of 0.010 to 0.015 (μm / mm) is more preferable.

The film thickness slope ΔT is
ΔT = (average thickness and maximum value of substrate film thickness difference in area [μm]) / (average of longitudinal length of uneven thickness area [mm])
Determined by
The maximum value of the substrate film thickness difference as used herein means the maximum film thickness in the linear region extending in the longitudinal direction of the long substrate in the region where the average value of the thickness of the long substrate is measured, and the average value It is the difference with the film thickness.
Further, the length in the longitudinal direction of the uneven thickness region is a value obtained by averaging five points in the width direction with respect to one uneven thickness region.

By setting the film thickness gradient ΔT in the above range, that is, by making the variation of the thickness of the long base material smooth, the variation of the thickness of the liquid crystal layer 3 is suppressed and the variation of the in-plane retardation of the liquid crystal layer 3 is smooth. Can be That is, the phase difference slope ΔRe can be reduced.
Further, the lower limit value of the film thickness gradient ΔT is a range in which a long base material can be continuously manufactured with industrially appropriate manufacturing efficiency and cost. Therefore, by setting ΔT in the above range, a long base material is industrially easily available, and the in-plane retardation of the liquid crystal layer 3 is small, which is preferable.

The long liquid crystal film of the present invention can have an in-plane retardation of at least 10 nm or more of Re (550). Preferably, Re (550) is in the range of 100 nm to 250 nm, and in this range, it can be used as various optical compensation films or wave plates. More preferably, Re (550) is in the range of 120 nm to 160 nm, and in this range, it can be used as a λ / 4 wavelength plate.

In addition, regarding the in-plane retardation of the long liquid crystal film, it is preferable that the in-plane retardation at each wavelength satisfy the following relationship.

0.6 <Re (450) / Re (550) <1.0
1.0 <Re (650) / Re (550) <1.2

When this relationship is satisfied, uniform polarization conversion over a wide band is possible, and good performance with little tinting can be exhibited when used as various optical compensation films or wavelength plates.

<Long base material>
The long base 1 is a member to be a support of the liquid crystal layer 3 and is a long film-like member.
The long base material 1 is preferably transparent. Specifically, the linear light transmittance of the visible light region is preferably 80% or more.
Moreover, it is preferable that the elongate base material 1 is an optically isotropic transparent film material from the viewpoint of the optical design of the whole liquid crystal film, and the optical orientation suitability mentioned later.

From the above viewpoints, examples of the long base material 1 include a cellulose acylate film, an acrylic film, a polycarbonate film, a cycloolefin film, a polyethylene terephthalate film, and a transparent film material made of glass. From the viewpoint of combining strength and flexibility, the long base material 1 is preferably a resin film such as a cellulose acylate film, an acrylic film, a polycarbonate film, a cycloolefin film, or a polyethylene terephthalate film.

(Cellulose acylate film)
A cellulose acylate film can be used as a long base material used in the present invention. It is preferably used in that it has both transparency and strength, and can easily control adhesion or peelability with each layer. As the cellulose acylate film, a film containing a cellulose acylate resin and, if necessary, an additive may be used. The cellulose acylate film can be produced by solution film formation, and may be produced using melt film formation.

As the cellulose acylate resin, triacetyl cellulose, diacetyl cellulose, and cellulose in which a part of acetyl group is substituted by higher acyl group, aromatic acyl group, alkoxy group or substituted alkoxy group can be used. In the cellulose acylate, the degree of substitution of the cellulose to hydroxyl groups is not particularly limited, but in order to provide appropriate moisture permeability and hygroscopicity, the degree of acyl substitution of the cellulose to hydroxyl groups is 2.00 to 3.00 Is preferred. Furthermore, the degree of substitution is preferably 2.30 to 2.98, more preferably 2.70 to 2.96, and still more preferably 2.80 to 2.94.

As the additive, for example, JP-A-2005-154764, JP-A-2013-228720, JP-A-2014-81619, JP-A-2014-178519, JP-A-2015-227956, JP-A 2016- Various additives described in JP-A-6439, JP-A-2016-164668, and JP-A-2017-106975 can be used.

As a preferable example of an additive, the polyester additive which has a repeating unit represented by the following general formula is mentioned.

General formula (1)

(In the general formula (1), X and Y each represent a divalent linking group.)

X may be an alkylene group having 2 to 20 carbon atoms which may have a substituent, a polyoxyalkylene group, an alkenylene group, a phenylene group, a naphthylene group or a heterocyclic aromatic group. In addition, the alkylene group in the said alkylene group, an alkenylene group, and a polyoxyalkylene group may have alicyclic structure.
Y may be an alkylene group having 2 to 20 carbon atoms which may have a substituent, a polyoxyalkylene group, an alkenylene group, a phenylene group, a naphthylene group or a heterocyclic aromatic group. In addition, the alkylene group in the said alkylene group, an alkenylene group, and a polyoxyalkylene group may have alicyclic structure.
These divalent linking groups may contain molecules other than carbon such as oxygen atom and nitrogen atom. Examples of the substituent mentioned above include an alkyl group, an alkoxy group, a hydroxyl group, an alkoxy substituted alkyl group and a carboxyl group.

As a repeating unit represented by the above-mentioned general formula (1), X represents a non-cyclic divalent linking group having 2 to 10 carbon atoms, in that it is excellent in retardation properties and elastic modulus of the film, and Y is 3 It is preferable to represent a C3-C12 linking group containing an alicyclic structure of a 6-membered ring. The alicyclic structure is a 3- to 6-membered ring, preferably a 5- to 6-membered ring, and specifically, a cyclopropylene group, a 1,2-cyclobutylene group, a 1,3-cyclobutylene group, a 1,2- Examples thereof include a cyclopentylene group, a 1,3-cyclopentylene group, a 1,2-cyclohexylene group, a 1,3-cyclohexylene group, and a 1,4-cyclohexylene group.

The hydrogen atom at the hydroxyl end of the polyester additive having a repeating unit represented by the above general formula (1) is substituted with an acyl group derived from a monocarboxylic acid (hereinafter also referred to as a monocarboxylic acid residue) It is preferable (hereinafter, also referred to as a hydrogen atom at a hydroxyl end is sealed). At this time, both ends of the polyester are monocarboxylic acid residues. By protecting the end with a hydrophobic functional group, the cohesion of the additive is suppressed, the compatibility with the film and the handling of the compound become good, and the temperature and humidity stability and the polarizer durability of the polarizing plate are excellent. Film can be obtained.

Here, a residue is a partial structure of the said polyester, and represents the partial structure which has the characteristic of the monomer which has formed the said polyester. For example, the monocarboxylic acid residue formed from the monocarboxylic acid R-COOH is R-CO-. As R, an alkyl group having 1 to 10 carbon atoms which may have a substituent, an alicyclic alkyl group and an aromatic group can be mentioned. The aliphatic monocarboxylic acid residue is preferably an aliphatic monocarboxylic acid residue, more preferably an aliphatic monocarboxylic acid residue having 2 to 10 carbon atoms, and an aliphatic monocarboxylic acid residue having 2 to 3 carbon atoms It is more preferably a group, and particularly preferably an aliphatic monocarboxylic acid residue having 2 carbon atoms.

It is preferable that the hydroxyl value of the polyester is 10 mg KOH / g or less from the viewpoint of improving the polarizer durability, more preferably 5 mg KOH / g or less, and particularly preferably 0 mg KOH / g. In addition, the number average molecular weight (Mw) of the polyester may be 500 to 3,000, and more preferably 700 to 2,000. It is excellent in compatibility as it is this range, and a stable film with little volatilization of additives at the time of film production and use can be obtained.

In addition, as another preferable example of the additive, a compound (sugar ester) in which at least one substitutable group (for example, a hydroxyl group, a carboxyl group) in the sugar skeleton structure and at least one kind of substituent are esterified Compounds) can be used. More specifically, a hydroxyl group of a compound (M) having 1 to 12 of at least one pyranose structure or furanose structure, or a compound (D) in which at least one furanose structure or pyranose structure is bound A sugar ester compound obtained by alkylating all or part of OH groups simply or preferably is preferably used.

Examples of the compound (M) include glucose, galactose, mannose, fructose, xylose or arabinose, preferably glucose and fructose, more preferably glucose. Examples of the compound (D) include lactose, sucrose, nystose, 1F-fructosyl nistose, stachyose, maltitol, lactitol, lactulose, cellulose, cellulose, cellotriose, maltotriose, raffinose, and kestose. Other than these, genthiobiose, genthiotriose, genthiotetraose, xylotriose, galactosyl sucrose and the like can also be mentioned. Among them, glucose, sucrose and lactose are preferred.

It is preferable to use an aliphatic monocarboxylic acid, a monocarboxylic acid having an alicyclic structure, or an aromatic monocarboxylic acid for alkylating all or part of OH groups in the compound (M) and the compound (D) . Examples of such monocarboxylic acids include acetic acid, propionic acid, butyric acid, isobutyric acid, benzoic acid and cyclohexanecarboxylic acid. Two or more of these monocarboxylic acids may be used in combination.

As other additives, plasticizers, UV absorbers, crosslinking agents, matting agents (inorganic fine particles), antioxidants, radical scavengers and the like may be added. As described later, in the case of forming a polarizing plate by making the base material of the retardation film of the present invention also serve as a polarizing plate protective film, the following general formula is further provided from the viewpoint of imparting the effect of improving the durability of the polarizer. It is preferable to contain the compound represented by these.

General formula (2)

In the general formula (2), each of R ¹¹ , R ¹³ and R ¹⁵ independently represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, or 2 to 20 carbon atoms Represents an alkenyl group or an aromatic group having 6 to 20 carbon atoms.)
Such compounds can be used, for example, those described in International Publication WO 2014/112575.

The cellulose acylate film used in the present invention can be produced using the method described in Japan Institute of Invention and Innovation Technical Publication No. 2001-1745 (Invention Association).
These cellulose acylate films can be obtained by uniaxially or biaxially stretching as required, and preferably those stretched in the transverse direction can be used. Moreover, it can also be extended in an oblique direction. The draw ratio in one direction can be 1.02 to 1.50 times, preferably 1.05 times to 1.30 times.

In the cellulose acylate film, the glass transition temperature can be 140 to 200 ° C., more preferably 160 to 190 ° C., and particularly preferably 170 to 185 ° C. Within this range, the resistance to thermal deflection is more excellent, and physical property control by the stretching process is easy. The glass transition temperature can be determined as a peak value of tan δ by a dynamic viscoelasticity measuring apparatus.

The film-like long body used as the long base material 1 is normally manufactured continuously by melt film forming or solution film forming. Of course, it is desirable that the film thickness be uniform, but in practice various oscillation factors (machine vibration of the apparatus, mechanical vibration of the apparatus, etc. in each manufacturing process such as extrusion or casting, cooling, drying, blowing, conveying mechanism, rolling and stretching) Due to air pressure vibration, etc., film thickness unevenness more than a certain level is present.
Specifically, as described above, the elongated base material 1 has a plurality of uneven thickness regions 5 extending in the width direction in the longitudinal direction. Such a thickness unevenness region 5 is long due to fluctuation of the discharge amount of the resin melt or resin solution at the time of extrusion or casting, roundness of various transport rolls, misalignment of alignment, drying wind at the time of drying, etc. A plurality appears in the longitudinal direction of the substrate. Therefore, the conventional film has such unevenness in film thickness to some extent. Typically, the thickness varies in a wavelike manner.

In the present invention, preferably, the film thickness gradient ΔT in the thickness unevenness region 5 extending in the width direction of the elongated base material 1 satisfies 0.005 to 0.025 (μm / mm). The variation in thickness of the liquid crystal layer 3 formed on the long base material 1 can be suppressed to reduce the retardation inclination ΔRe of the liquid crystal layer 3.

In order to make the film thickness gradient ΔT in the above range, the viscosity of a resin melt or a resin solution (hereinafter collectively referred to as a resin solution) at the time of extrusion or casting is reduced when manufacturing the long base material 1 It is preferable to adjust the length of the bead until the cast (or extruded) resin solution reaches the support to promote leveling, and the strength of the bead against disturbance.

Specifically, when adjusting the bead length of the resin solution during casting (or extrusion) and the strength of the bead against disturbance, the bead portion until the cast resin solution reaches the support On the other hand, the bead can be made shorter by attracting it from the upstream side in the traveling direction of the support by the suction device, thereby making it possible to resist against disturbance.
The suction pressure to the bead is preferably −1000 Pa <the suction pressure to the bead <−200 Pa, more preferably −900 Pa <the suction pressure to the bead <−300 Pa, and −800 Pa <the suction pressure to the bead More preferably, it is <−350 Pa.

In addition, the bead can be made more resistant to disturbance also by the increase in dope viscosity. For example, it is achieved by use of a high viscosity solvent, dope temperature down, dope solid concentration up.
Assuming that the viscosity of the resin solution discharged from the discharge device is η, it is preferable to satisfy η> 25 Pa · s.
Here, η is the vibrational viscosity (unit: Pa · s) of the viscosity of the resin solution discharged from the discharge device measured at 25 ° C. and 1 Hz.
The viscosity of the resin solution discharged from the discharge device is more preferably 30 Pa · s <η <200 Pa · s, still more preferably 40 Pa · s <<< 200 Pa · s, and 40 Pa · s <η <100 Pa S is particularly preferred.

When the viscosity is lowered to promote leveling, it is preferable that the solid content concentration in the resin melt or resin solution during extrusion or casting be 25% or less, and the viscosity be 50 Pa · s or less.
The solid content concentration in the resin solution is more preferably 10% or more and 23% or less, and still more preferably 12% or more and 20% or less. The viscosity is more preferably 1 Pa · s or more and 40 Pa · s or less, and still more preferably 3 Pa · s or more and 20 Pa · s or less.

Here, since the method of strengthening the bead against disturbance and the method of promoting the leveling by lowering the viscosity are contradictory, it is preferable to promote the leveling by slow drying. For example, thickness nonuniformity can be reduced by airless drying or the like.

The long substrate 1 preferably has an in-plane retardation Re (550) of 10 nm or less, more preferably 5 nm or less, from the viewpoint of suppressing the influence of film thickness unevenness on the whole liquid crystal film. It is further preferred that
Further, from the viewpoint of suppressing the optical influence in the oblique direction, the thickness direction retardation Rth (550) of the elongated base material 1 is preferably in the range of -20 to 20 nm, and in the range of -10 to 10 nm Is more preferable, and the range of -5 to 5 nm is more preferable. Here, if Rth is in this range, it becomes difficult to optically detect the film thickness unevenness of the long base material immediately before the application of the coating liquid for forming the liquid crystal layer and to feed it back to the coating apparatus. Even if it is such an optically isotropic long base material, a long liquid crystal film with little unevenness can be obtained without any problem. The details will be described later.

The thickness of the elongated substrate 1 is not particularly limited, but is preferably 10 μm to 60 μm, more preferably 15 μm to 50 μm, and still more preferably 15 μm to 45 μm.
The length of the elongated base material 1 is preferably 100 m to 10000 m, more preferably 250 m to 7000 m, and still more preferably 1000 m to 6000 m. The width is preferably 400 to 3000 mm, more preferably 500 to 2500 mm, and still more preferably 600 to 1750 mm. Within this range, it is possible to improve the economy in the roll-to-roll process, and to manufacture a long liquid crystal film excellent in the uniformity in the longitudinal direction and the lateral direction.

<Alignment layer>
The alignment layer 2 is a layer which is formed on the long base material 1 and aligns the liquid crystal compound of the liquid crystal layer 3 formed on the alignment layer 2 by the alignment regulating force.
The alignment layer 2 can apply various configurations capable of aligning the liquid crystal compound to be the liquid crystal layer 3. For example, a rubbed film of a layer containing an organic compound such as a polymer or the like, an oblique deposition film of an inorganic compound, a film having a microgroove, or an organic compound such as ω-trichosanic acid, dioctadecyl methyl ammonium chloride or methyl stearylate The film etc. which accumulated LB (Langmuir-Blodgett) film | membrane by the Langmuir-Blodgett method etc. are mentioned. Furthermore, the alignment film etc. which an alignment function produces by irradiation of light are mentioned.

As the alignment layer, one formed by rubbing the surface of a layer (polymer layer) containing an organic compound such as a polymer can be preferably used. The rubbing treatment is carried out by rubbing the surface of the polymer layer with paper or cloth several times in a certain direction (preferably the longitudinal direction of the support). Examples of the polymer used to form the alignment layer include polyimide, polyvinyl alcohol, modified polyvinyl alcohol described in paragraph Nos. [0071] to [0095] of Japanese Patent No. 3907735, and polymerization described in JP-A-9-152509. It is preferable to use a polymer having a functional group.

In addition, it is also a preferable embodiment to use a so-called photo alignment layer (photo alignment film), which is an alignment layer, by irradiating a light alignment material with polarized light or non-polarized light as the alignment layer. It is preferable to apply an alignment regulating force to the photoalignment layer by the step of irradiating polarized light from the vertical direction or the oblique direction or the step of irradiating non-polarized light from the oblique direction. By using the photoalignment layer, it is possible to align the polymerizable liquid crystal compound described later with excellent symmetry.
From the viewpoint of suppressing foreign matter defects and obtaining a long liquid crystal film without unevenness, it is preferable to use a photoalignment film which can impart an alignment control force without contact.

The photoalignment layer may be formed by irradiating the ultraviolet light by the linearly polarized light after forming the material layer to be the photoalignment layer on the long base material 1 by coating and drying the coating liquid to be the photoalignment layer. it can. As the material to be the photoalignment layer, various materials to which a photoalignment method can be applied can be applied. As a preferred embodiment, for example, a photodimerization type material, particularly a compound containing a cinnamic acid derivative can be used. . Moreover, photoisomerization materials, such as an azo compound, can also be used suitably.

Examples of the photoalignment material used for the photoalignment layer include, for example, JP-A-2006-285197, JP-A-2007-76839, JP-A-2007-138138, JP-A-2007-94071, and JP-2007-. No. 121721, JP-A-2007-140465, JP-A-2007-156439, JP-A-2007-133184, JP-A-2009-109831, Patent Nos. 3883848, and No. 4151746 , An aromatic ester compound described in JP-A-2002-229039, a maleimide and / or alkenyl-substituted nadiimide compound having a photoalignable unit described in JP-A-2002-265541 and JP-A-2002-317013; No. 4,205,195, patent No. 420 Photocrosslinkable silane derivatives described in JP-A No. 198, Photo-crosslinkable polyimides, polyamides, or esters described in JP-A-2003-520878, JP-A-2004-529220, and JP-A-4162850, JP-A-9-118717 Patent Document 1: JP-A-10-506420, JP-A-2003-505561, WO 2010/150748, JP-A 2013-177561, JP-A 2014-12823, and compounds capable of photodimerization In particular, cinnamate compounds, chalcone compounds and coumarin compounds can be mentioned. Particularly preferred examples include azo compounds, photocrosslinkable polyimides, polyamides, esters, cinnamate compounds and chalcone compounds.

The thickness of the alignment layer is not particularly limited as long as the alignment function can be exhibited, but is preferably 0.01 to 5 μm, more preferably 0.05 to 2 μm, and further preferably 0.1 to 0.5 μm. It is further preferred that Within this range, an excellent alignment regulation force can be exhibited, and the effect of suppressing foreign matter defects is high.

The long base material 1 and the alignment layer 2 may be separately provided as layers performing the respective functions, or the long base material 1 doubles as the alignment layer 2, that is, the long base material surface controls the alignment. You may take a mode that has power. Moreover, when the long base material 1 and the alignment layer 2 are provided separately, the long base material 1 and the alignment layer 2 may be provided in contact with each other, or the long base material 1 and the alignment layer 2 may be provided. A functional layer may be interposed between the two. The long base material 1 is subjected to the above-described processing such as rubbing or polarized light irradiation on the surface of the long base material 1 as means for directly applying the alignment regulating force without providing the alignment layer 2 on the surface of the long base material 1. It is possible to adopt a method of orienting the polymer constituting the long base material 1 by stretching in a predetermined direction. Examples of the above-mentioned functional layer that can be interposed between the long base material 1 and the alignment layer 2 include a barrier layer, an impact relaxation layer, an easily peelable layer, and an easily adhesive layer.

<Liquid crystal layer>
The liquid crystal layer 3 is a long layer formed on the long base 1 (alignment layer 2) using a composition containing a liquid crystal compound.
The liquid crystal layer 3 is formed by curing in a state in which a liquid crystal compound to be the liquid crystal layer 3 is aligned by the alignment regulating force of the alignment layer 2. Therefore, the liquid crystal layer 3 has optical characteristics according to the alignment state of the liquid crystal compound.

The liquid crystal layer 3 can have an in-plane retardation of at least Re (550) of 10 nm or more. Preferably, Re (550) is in the range of 100 nm to 250 nm, and in this range, it can be used as various optical compensation films or wave plates. More preferably, Re (550) is in the range of 120 nm to 160 nm, and in this range, it can be used as a λ / 4 wavelength plate.
In the case where the liquid crystal layer 3 is a λ / 4 wavelength plate, it is preferable that the ground phase axis make 45 ° with the longitudinal direction of the long base material 1.

The refractive index anisotropy Δn of the liquid crystal layer 3 is preferably in the range of 0.03 to 0.20, and more preferably in the range of 0.05 to 0.15. Within this range, it is more difficult to visually recognize retardation unevenness, and it is possible to obtain a desired high retardation with a thin liquid crystal layer. The thickness of the liquid crystal layer 3 can be appropriately set according to the refractive index anisotropy and the target retardation value, but is typically in the range of 0.5 μm to 7 μm, and more preferably 0.7 to 5 μm, More preferably, it is in the range of 1.0 to 3.0 μm.

Regarding the in-plane retardation Re of the liquid crystal layer 3, it is preferable that the in-plane retardation at each wavelength satisfy the relationship of Re (450) <Re (550) <Re (650).
When this relationship is satisfied, uniform polarization conversion over a wide band is possible, and good performance with little tinting can be exhibited when used as various optical compensation films or wavelength plates.

Here, as described above, in the present invention, the liquid crystal layer 3 has a strip-like in-plane retardation unevenness region 6 extending in the width direction, and the retardation inclination ΔRe of the in-plane retardation unevenness region is 0 The range is from 002 to 0.018 (nm / mm).

The liquid crystal layer 3 is formed by applying a coating solution to be the liquid crystal layer 3 to the long base material 1 with a coating head such as a die, drying it, and then irradiating it with ultraviolet rays to cure it. At the time of coating, the amount of the coating liquid supplied from the coating device to the long base 1 fluctuates due to the uneven thickness region 5 extended in the width direction of the long base 1. Therefore, the thickness of the liquid crystal layer 3 also varies in the longitudinal direction. Since the in-plane retardation of the liquid crystal layer 3 correlates with the thickness of the liquid crystal layer 3, the in-plane retardation of the liquid crystal layer 3 is caused by the fluctuation of the thickness of the liquid crystal layer 3. Unevenness occurs. Specifically, the liquid crystal layer 3 has a plurality of streak-like in-plane retardation unevenness regions 6 extending in the width direction corresponding to the thickness unevenness regions 5 of the elongated base 1 in the longitudinal direction. .

Here, in the case of small local thickness unevenness of the base material that has been focused on in the past, the unevenness is eliminated to such an extent that the unevenness is not visible in the state of the liquid crystal film due to the leveling property of the coating liquid itself. However, such thickness unevenness extending in the width direction can not be resolved only by the leveling property of the liquid because it occurs simultaneously in the width direction at the time of long coating, and can be visually observed because it extends long in one direction. It is easy to remain in

On the other hand, in the present invention, cutting out the long liquid crystal film 10 by setting the retardation slope ΔRe of the in-plane retardation unevenness region of the liquid crystal layer to be in the range of 0.002 to 0.018 (nm / mm) In the display device having the liquid crystal film, it is possible to suppress the occurrence of front color unevenness in the screen. Moreover, individual differences in frontal color when cutting a plurality of liquid crystal films from a long liquid crystal film can be suppressed by smoothing variation in retardation in the plane.

In forming the liquid crystal layer 3 in order to set the retardation inclination ΔRe in the above range, various amounts of the amount of the coating liquid applied onto the long base material are stabilized regardless of the thickness unevenness of the long base material Take measures. The specific method will be described in detail later.

<< Polymerizable Liquid Crystal Composition >>
The liquid crystal layer 3 is formed of a polymerizable liquid crystal composition containing a polymerizable liquid crystal compound exhibiting optical anisotropy. The polymerizable liquid crystal composition exhibits liquid crystallinity and can contain, in addition to the polymerizable liquid crystal compound having a polymerizable functional group in the molecule, other polymerizable compounds, an alignment stabilizer, a polymerization initiator, a solvent and the like. .

(Polymerizable liquid crystal compound)
The polymerizable liquid crystal compound contained in the polymerizable liquid crystal composition has refractive index anisotropy, and has a function of imparting a desired retardation by arranging regularly by the alignment regulating force of the alignment layer 2 . Examples of the polymerizable liquid crystal compound include materials exhibiting a liquid crystal phase such as a nematic phase and a smectic phase. In addition, polymerizable liquid crystal molecules having various structures such as a rod-like liquid crystal compound and a discotic liquid crystal compound can be used.

As polymerizable liquid crystal compounds used in the present embodiment, JP-A-8-50206, JP-A2007-2220, JP-A-2010-244038, JP-A-2008-19240, and JP-A-2013-166879. JP 2014-78036 A, JP 2014-198813 A, JP 2011-6360 A, JP 2011-6361 A, JP 2011-207765 A, JP 2008-273925 A, The compounds described in JP-A-2015-200877 can be used. From the viewpoint of adjusting the phase transition temperature and suppressing the crystallization of the polymerizable liquid crystal compound to obtain a liquid crystal film having a more excellent surface shape, a plurality of different polymerizable liquid crystal compounds can be mixed and used.

(Other polymerizable compounds)
The polymerizable compound contained in the polymerizable liquid crystal composition can preferably have a non-liquid crystalline polyfunctional polymerizable compound. Examples of such non-liquid crystalline polyfunctional polymerizable compounds include ester compounds of known polyhydric alcohols and (meth) acrylic acid. The addition of these compounds increases the fluidity of the polymerizable liquid crystal composition to promote leveling, so that the liquid crystal layer 3 with less variation in retardation can be obtained. In addition, by adjusting the number of polymerizable functional groups, the wet heat durability of the liquid crystal layer 3 can be improved, and the scratch resistance and the film strength can be enhanced.

(Alignment stabilizer)
An alignment stabilizer can be added to the polymerizable liquid crystal composition. By the addition of the alignment stabilizer, various disturbance factors are suppressed, the alignment of the liquid crystal compound is stabilized, and it is possible to obtain the liquid crystal layer 3 with less phase difference unevenness. In addition, by appropriately selecting the structure of the alignment stabilizer, the alignment of the liquid crystal layer can be adjusted to any alignment such as horizontal alignment, vertical alignment, hybrid alignment, and cholesteric alignment. From the viewpoint of achieving both orientation stabilization and leveling, an acrylic polymer having a fluoroaliphatic side chain is particularly preferable (paragraphs 0022 to 0063 of JP-A-2008-257205, and paragraph 0017 of JP-A-2006-91732). Can be added).

(Polymerization initiator)
The polymerizable liquid crystal composition can contain a polymerization initiator. Various polymerization initiators can be selected according to the polymerizable group of the polymerizable liquid crystal compound. Preferably, the polymerizable liquid crystal compound is a (meth) acrylate compound, and the polymerization initiator is a radical polymerization initiator. As such polymerization initiators, various well-known polymerization initiators can be used. In order to achieve uniform orientation, it is preferable that the stability with time of the coating solution and the deep-part curability of the coating film be excellent, and from that viewpoint the oxime ester compound (US Pat. No. 4,255,513) And JP-A-2001-233842 and acyl phosphine oxide compounds (Japanese Patent Publication No. 5-29234, JP-A-10-95788, JP-A-10-29997, etc.) are preferably used.

(solvent)
Various known solvents can be used as the solvent. The solvent is preferably selected in consideration of the solubility of the polymerizable liquid crystal compound and the other components, the wettability to the long base of the coating solution, the surface tension, the viscosity, and the volatilization. By appropriately selecting the solvent, it is possible to form a coating film excellent in leveling property and uniform without unevenness, and it is possible to obtain the liquid crystal layer 3 in which the retardation unevenness is suppressed.

The amount of solvent in the polymerizable liquid crystalline composition is preferably between 50% by mass and 90% by mass, and more preferably in the range of 60 to 85% by mass, with respect to the total amount of the composition. When it is in this range, by exhibiting excellent leveling properties and having an appropriate viscosity, it becomes difficult to be disturbed by external factors, and it is possible to effectively suppress the film thickness fluctuation due to the film thickness unevenness of the long base material. .

In the long liquid crystal film shown in FIG. 1, the alignment layer 2 and the liquid crystal layer 3 are formed on the long base material 1, but the invention is not limited thereto.
The long substrate 1 may be a peelable support, and the liquid crystal layer 3 or a laminate of the alignment layer 2 and the liquid crystal layer 3 may be peelable from the long substrate 1. Alternatively, it may be configured to be peelable between the alignment layer 2 and the liquid crystal layer 3. The liquid crystal layer 3 or a laminate of the alignment layer 2 and the liquid crystal layer 3 can be peeled off from the long base 1 and transferred to another member for use.

In the case of such a configuration, since the long base material 1 is peeled off and removed, a film having an optical characteristic that is not appropriate when used as the long liquid crystal film 10 is also used as the long base material. Is possible. Specifically, it is possible to use a long body of a high retardation film having an in-plane retardation of 500 nm or more, a base material having high light scattering property, a base material having high light absorption property, or the like. It is often difficult to detect such film thickness variations before coating and feed them back to the coating apparatus optically (for example, in-plane retardation and transmittance etc.), although such films are also difficult according to the present invention. Even a film can be used without problems, and a high quality liquid crystal layer can be obtained.

Further, in order to form the liquid crystal layer 3 (and the alignment layer 2) in a peelable manner, a release layer may be provided on the surface of the long base material 1, and a release layer may be provided on the alignment layer 2.

The long liquid crystal layer thus obtained can be transferred to a linear polarizing plate or the like to be used as various optical components, particularly preferably a circularly polarizing plate.

[Method for producing long liquid crystal film]
The method for producing a long liquid crystal film of the present invention is
A method for producing a long liquid crystal film, wherein a long liquid crystal layer is provided on a long base material,
Preparing a long base roll having a plurality of streaky uneven thickness regions extending in the width direction in the longitudinal direction;
While feeding the long base material from the long base material roll and conveying it in the longitudinal direction, sequentially
An orientation step of applying an orientation regulating force to a long substrate in a long shape,
A step of applying the polymerizable liquid crystal composition in the form of a long on the region of the long substrate to which the alignment control force is applied,
After a coating liquid layer formed by coating is subjected to alignment treatment, it is cured to fix the alignment state, and a liquid crystal layer forming step of forming a liquid crystal layer,
Winding a long liquid crystal film in which a liquid crystal layer and a long base material are laminated in a roll shape;
In the coating step, a means for adjusting the thickness of the coating liquid layer laminated on the long base material is taken constant, and the variation of the thickness is within ± 2% of the average thickness. It is a manufacturing method.

FIG. 3: is the figure which represented typically the manufacturing apparatus which enforces the manufacturing method of the elongate liquid crystal film of this invention.
The manufacturing apparatus 30 illustrated in FIG. 3 includes a rotating shaft 60, an application unit 32, a heating unit 33, a light source 34, a backup roll 38, an application unit 35, a heating unit 36, a light source 37, and a winding shaft And 62.
The manufacturing apparatus 30 forms the photoalignment layer 2 and the liquid crystal layer in order while transporting the long base material 1 in the longitudinal direction along a predetermined transport path.

The rotating shaft 60 is for loading a base material roll 31 in which the long base material 1 is wound. In addition, the winding shaft 62 is a winding shaft of a known long object for winding the long base material 1 after the formation of the light alignment layer 2 and the liquid crystal layer 3. The backup roll 38 is a backup roll that supports the long base material 1 from the back side during the formation (light irradiation) of the light alignment layer 2.

The application part 32 is a site | part which coats the coating liquid used as the photo-alignment layer 2 on the elongate base material 1 (application | coating). In addition, the application portion 35 is a portion for applying a coating liquid to be the liquid crystal layer 3 on the photoalignment layer 2 formed on the long base material 1.
There is no limitation on the coating method in the coating unit 32 and the coating unit 35, and a coating method capable of coating the photoalignment layer 2 and the liquid crystal layer 3 to a desired thickness may be used, respectively. Therefore, all known coating methods such as die coating method, dip coating method, air knife coating method, curtain coating method, roller coating method, wire bar coating method, gravure coating method and slide coating method can be used.
Among other things, the coating solution can be applied without contact, so the surface of the long substrate 1 is not damaged, and the formation of the beads is excellent in embedding properties such as irregularities on the surface of the long substrate 1, etc. Is preferably used.

The heating portion 33 and the heating portion 36 are portions for heating and drying the coating liquid layer to be the photo alignment layer 2 applied on the long base 1 or the coating liquid layer to be the liquid crystal layer 3. .
The drying method by the heating unit 33 and the heating unit 36 is not limited, and the coating liquid layer or the coating liquid layer may be dried to remove the organic solvent or the like so that crosslinking can be performed, All known drying means are available. As an example, heat drying by a heater, heat drying by warm air, etc. are exemplified.

The light source 34 and the light source 37 respectively irradiate the ultraviolet rays or visible light to the coating liquid layer or the coating liquid layer after drying to crosslink organic compounds such as monomers contained in the coating liquid layer and the coating liquid layer. It is cured to form the photoalignment layer 2 or the liquid crystal layer 3.
The wavelength of the light emitted by the light source may be set according to the material contained in the coating liquid, the material contained in the coating liquid, and the like. The light source is not limited as long as it can emit light of the set wavelength, and a known light source used in a liquid crystal film manufacturing apparatus can be appropriately used.

In addition to the illustrated members, the manufacturing apparatus 30 transports a long substrate such as a transport roller, a guide member that regulates the position of the long substrate 1 in the width direction, various sensors, etc. May have various members provided in known devices for forming

Next, each process of the manufacturing method of the elongate liquid crystal film of this invention implemented with the manufacturing apparatus 30 shown in FIG. 3 is demonstrated.
First, as a preparation step, a base material roll 31 is formed by winding a long base material having a plurality of streaky uneven thickness regions extending in the width direction along the longitudinal direction and having an in-plane retardation Re of 5 nm or less. Prepare.
The base material roll 31 is set on the rotating shaft 60, and the long base material 1 is pulled out from the base material roll 31 and passed through a predetermined transport path from the rotating shaft 60 to the winding shaft 62.

Moreover, the coating liquid used as the photo-alignment layer 2 prepared beforehand is supplied to the application part 32. Similarly, the coating solution to be the liquid crystal layer 3 prepared in advance is supplied to the coating unit 35.

In the manufacturing apparatus 30, the feeding of the long base material 1 from the base material roll 31 and the winding of the long base material 1 on which the liquid crystal layer 3 is formed on the winding shaft 62 are performed in synchronization with each other. While conveying the material 1 in the longitudinal direction along a predetermined conveyance path, formation of the photoalignment layer 2 (alignment step) and formation of the liquid crystal layer 3 (coating step, liquid crystal layer formation step) are continuously performed.

In the manufacturing apparatus 30, the photo alignment layer 2 is formed as an alignment step.
Specifically, the coating unit 32 disposed in the middle of the transport route of the long base 1 coats the long base 1 with the coating liquid to be the photoalignment layer 2. Next, the heating unit 33 disposed on the downstream side of the application unit 32 heats and dries the coating liquid layer to be the coated light alignment layer 2. Next, the light source 34 disposed downstream of the heating unit 33 irradiates linearly polarized ultraviolet light to cure the coating liquid layer, thereby forming the photoalignment layer 2. At this time, the exposure from the light source 34 uses the backup roll 38 to prevent the web from vibrating.

Next, in the coating step, the coating unit 35 disposed on the downstream side of the light source 34 coats the coating liquid to be the liquid crystal layer 3 on the long base material 1 (photoalignment layer 2).
Next, in the liquid crystal layer forming step, the heating unit 36 disposed on the downstream side of the coating unit 35 heats and dries the coating liquid layer to be the coated liquid crystal layer 3. If necessary, heating or cooling may be further performed to promote the alignment of the liquid crystal compound contained in the polymerizable liquid crystal composition or to adjust the alignment state.

Here, in the application step of applying the coating liquid to be the liquid crystal layer 3 to the long base material 1, means for adjusting the thickness of the coating liquid layer to a constant value is taken.
In addition to the thickness unevenness of the long base material, the thickness unevenness of the liquid crystal layer generated in the coating process is caused due to the mechanical vibration and the air pressure vibration of the coating device. Therefore, in addition to the thickness nonuniformity reduction of a support body, the thickness nonuniformity of a liquid crystal layer can be reduced by measures with respect to the cause derived from a coating process.
In the coating step, a means for adjusting the thickness of the coating liquid layer is taken constant, and the variation of the thickness of the liquid crystal layer is made within the range of ± 2% with respect to the average thickness. By this, it is possible to make the retardation slope ΔRe of the in-plane retardation unevenness region in the range of 0.002 to 0.018 (nm / mm).
The variation in thickness of the liquid crystal layer is preferably in the range of ± 1%, more preferably in the range of ± 0.5%, and still more preferably in the range of ± 0.3%.
The average thickness of the liquid crystal layer is obtained by measuring the thickness of the liquid crystal layer of the liquid crystal film cut out by 1 m in the longitudinal direction of the long base at 500 points every 2 mm and taking the average value. Further, the difference (ratio) between the thickness at each point and the average thickness is taken as the variation.

(Thickness of liquid crystal layer)
The thickness of the liquid crystal layer is measured at a lens magnification of 25 times using an interference film thickness measurement apparatus (FE3000 manufactured by Otsuka Electronics Co., Ltd.). The refractive index of each of the substrate, alignment film, and liquid crystal layer at 400 nm to 800 nm is calculated by the base analysis method, and fitting is performed at the wavelength of 400 nm to 800 nm by the optimization method using the calculated refractive index. calculate. The unit of film thickness is [nm].

For example, when the die coating method is used as the coating method performed by the coating unit 35, a minute clearance is provided between the die and the photo alignment layer so that the die does not contact the photo alignment layer. The portion of the coating solution (bead) until reaching the alignment layer is susceptible to vibration and the like. In addition, the bead is likely to be disturbed also when the stripe-like thickness unevenness region extended in the width direction of the elongated base material 1 passes the position of the die. Therefore, for example, the amount of clearance is adjusted to shorten the bead, the air pressure in the space before and after the flow of the coating liquid is adjusted in the clearance portion, that is, the air pressure is drawn to suck the bead from the upstream side in the transport direction. By taking measures such as adjusting and shortening the bead, it is possible to form a coating liquid layer having a uniform thickness and no unevenness regardless of the shape of the long base material 1.
It is also preferable to make the bead more resistant to disturbance by lowering the temperature of the coating chamber or adding a high viscosity solvent to the coating liquid to increase the viscosity of the coating liquid. For example, the viscosity of the coating solution can be increased by adding cyclopentanone as a high viscosity solvent.

In addition, in application | coating of the coating liquid used as a photo-alignment layer, and the coating liquid used as a liquid crystal layer as mentioned above, not only the coating by a die | dye but various methods are widely applicable. Therefore, it is possible to obtain the same effect by adjusting the amount of the coating liquid and the coating liquid applied to the long base material to be constant by taking appropriate measures according to the coating method. For example, in the case of using a bar coating method or a gravure coating method, it is possible to implement measures such as suppressing the fine vibration of the coater due to the streaked film thickness fluctuation of the long base material by a mechanism.

Further, the light source 37 disposed on the downstream side of the heating unit 36 irradiates ultraviolet light, and the liquid crystal compound is cured in a state of being aligned by the alignment regulating force of the photoalignment layer 2 to form the liquid crystal layer 3. Here, the irradiation of the ultraviolet light by the light source 37 is performed from the side of the coating liquid layer to be the liquid crystal layer 3, whereby the liquid crystal layer 3 can be formed by efficiently irradiating the ultraviolet light onto the coating liquid layer. At the time of irradiation with ultraviolet light, the atmosphere may be replaced with nitrogen.

Next, in the winding process, the long base 1 on which the light alignment layer 2 and the liquid crystal layer 3 are formed, that is, the long liquid crystal film 10 is wound around the winding shaft 62.
The wound liquid crystal film roll 39 is subjected to the next step as required.

In the example shown in FIG. 3, the photoalignment layer 2 and the liquid crystal layer 3 are continuously formed in one transport path, but the invention is not limited thereto. The photoalignment layer 2 and the liquid crystal layer It is good also as composition formed with a manufacturing device different from 3, respectively.

[Optical parts]
The long liquid crystal film of the present invention can be used as an optical component (for example, a polarizing plate) which can be used for various display devices by combining it with a linear polarizer. In combination, bonding can be performed using various adhesives. As such an adhesive agent, an ultraviolet curable resin, a thermosetting resin, a pressure sensitive adhesive agent etc. can be illustrated, for example.

<Long polarizing plate>
The long polarizing plate of the present invention includes the above-described long liquid crystal film and a long linear polarizer.
FIG. 4 is a schematic view showing an example of the long polarizing plate of the present invention.
The long polarizing plate 20 shown in FIG. 4 has a long liquid crystal film 10 and a linear polarizer 21 laminated on the long base 1 side of the long liquid crystal film 10.

Thus, the long polarizing plate 20 can be configured by laminating the long liquid crystal film of the present invention and the long linear polarizer. For example, when the long polarizing plate 20 is configured as a circularly polarizing plate, the in-plane retardation of the long liquid crystal film of the present invention is preferably in the range of 120 to 160 nm, and more preferably in the range of 130 to 150 nm. Further, the slow axis of the long liquid crystal film of the present invention is disposed at 45 ° to the transmission axis of the linear polarizing plate. A long linear polarizer 21 having a slow axis of the long liquid crystal film of the present invention at 45 ° to the transport direction and having a transmission axis in the width direction, or a long straight having the transmission axis in the transport direction By laminating with the polarizer 21, a long circularly polarizing plate can be configured.

(Linear polarizer)
The linear polarizer 21 is configured by sandwiching an optical functional layer having a function as a linear polarizer by a pair of base materials. Here, the substrate is a transparent film made of TAC (triacetyl cellulose), an acrylic resin such as methyl poly (meth) acrylate, a copolymer thereof, a crosslinked polymer resin such as an epoxy compound, a (meth) acrylate compound, cycloolefin Resin, resin such as polycarbonate resin, glass, etc. can be applied. The long base material of the long liquid crystal film of the present invention may be used as a base material, and the optical function layer, the long base material 1, the light alignment layer 2 and the liquid crystal layer 3 may be laminated in this order. The optical functional layer is typically produced by adsorbing and orienting iodine compound molecules to a film material of polyvinyl alcohol (PVA), but in addition, a film using an organic dichroic dye instead of the iodine compound molecules, organic A layer in which a dichroic dye is blended in a liquid crystal composition and oriented, a layer in which a liquid crystalline organic dichroic dye is oriented, or the like may be used. Various well-known adhesives mentioned above can be used as an adhesion layer (not shown) concerning lamination.

FIG. 5 shows a laminating apparatus for manufacturing the long polarizing plate 20 by laminating the long liquid crystal film 10 and the long linear polarizer 21.
The laminating apparatus 40 shown in FIG. 5 is a known laminating apparatus for laminating two long film-like materials.
The laminating apparatus 40 includes a rotating shaft 64 loaded with a liquid crystal film roll 39, a winding shaft 66 for winding the produced long polarizing plate 20, and a polarizer roll obtained by winding a long linear polarizer 21. 42, a take-up shaft 70 for winding the release film 41 removed from the linear polarizer 21, a release roll 43 for releasing the release film 41 from the linear polarizer 21, and a linear polarizer 21. And a pressure roll 45 for pressing the long liquid crystal film 10.

In the laminating apparatus 40, the long liquid crystal film 10 is pulled out from the liquid crystal film roll 39 loaded on the rotating shaft 64, and is passed through a transport path leading to the winding shaft 66. In addition, the polarizer roll 42 loaded on the rotating shaft 68 is formed by winding the long linear polarizer 21 in which the adhesive layer 22 and the peeling film 41 made of PET (polyethylene terephthalate) film are laminated in a roll shape. It is a thing. The laminate is pulled out of the polarizer roll 42, and the peeling film 41 is peeled off at the position of the peeling roll 43. The release film 41 is passed through the winding shaft 70. On the other hand, the laminate of the linear polarizer 21 and the adhesive layer 22 is laminated on the long liquid crystal film 10 at the position of the pressure roll 45 and is passed through a transport path leading to the winding shaft 66.
The laminating apparatus 40 synchronizes the rotating shaft 64, the winding shaft 66, the rotating shaft 68, the winding shaft 70, the peeling roller 43, and the pressure roller 45 with the transport of the linear polarizer 21 and the long liquid crystal film 10. And rotate. The laminating apparatus 40 peels off the peeling film 41 by the peeling roll 43 while pulling out the laminated body of the linear polarizer 21, the adhesive layer 22 and the peeling film 41 from the polarizer roll 42, and takes up the peeling film 41 peeled off. Roll into rolls. In addition, while the long liquid crystal film 10 is drawn out from the liquid crystal film roll 39, the release film 41 is laminated with the linear polarizer 21 and the adhesive layer 22 formed, and then pressure is applied by the pressure roll 45. A laminate of the film 10, the adhesive layer 22, and the linear polarizer 21 (that is, the long polarizing plate 20) is manufactured. The long polarizing plate 20 is wound in a roll shape on a winding shaft 66.

The long polarizing plate 20 is cut into a desired size to be a sheet-like polarizing plate, and is applied to an image display device or the like. Moreover, you may arrange | position an adhesive layer, a separator film, etc. suitably to the elongate polarizing plate 20, or the cut-out polarizing plate.

Moreover, although it was set as the structure which laminates a linear polarizer on the separately produced elongate liquid crystal film in the example shown in FIG. 5, limitation is not carried out to this, manufacture of an elongate liquid crystal film and lamination of a linear polarizer It is good also as a structure which performs continuously in the same conveyance path | route.

The long polarizing plate may further include a positive C plate having a thickness direction retardation (Rth (550)) at a wavelength of 550 nm of −150 to −50 nm. By including the positive C plate, the reflectance and the reflective color of the display can be further suppressed.
The retardation (Rth (550)) in the thickness direction at a wavelength of 550 nm of the positive C plate is -150 to -50 nm, preferably -130 to -70 nm, and more preferably -120 to -80 nm.

The thickness of the positive C plate is not particularly limited, but is preferably 0.5 to 10 μm and more preferably 0.5 to 5 μm from the viewpoint of thinning.
In addition, the said thickness intends average thickness, measures the thickness of arbitrary five points of positive C plate, and carries out the arithmetic mean of them.

The material constituting the positive C plate is not particularly limited, but preferably contains a liquid crystal compound. The definition of the liquid crystal compound is as described above. Among them, the positive C plate is preferably a layer formed by fixing a liquid crystal compound having a polymerizable group (a rod-like liquid crystal compound or a disc-like liquid crystal compound) by polymerization or the like. No longer needs to exhibit liquid crystallinity.

(Other optical parts)
The long liquid crystal film of the present invention is applicable not only to a circularly polarizing plate but also to various optical parts. For example, it is a polarizing plate with an optical compensation layer of a liquid crystal display device, a polarization sunglasses, a brightness enhancement plate, a decorative film, a viewing angle limiting film, a light control film, and the like. The optical characteristics and the average slow axis direction of the elongated liquid crystal film of the present invention can be variously changed according to the application without departing from the spirit of the present invention.

[Image display device]
The image display apparatus of the present invention is an image display apparatus including a polarizing plate cut out from the long polarizing plate. By appropriately cutting the long polarizing plate and mounting it on the display device, an image display device excellent in display quality can be configured.
FIG. 6 is a cross-sectional view schematically showing an example of the image display device of the present invention. In the image display device 50 shown in FIG. 6, the anti-reflection film 52 cut out from the long polarizing plate 20 is disposed on the panel surface (viewer side surface) of the image display panel 51. The anti-reflection film 52 prevents internally reflected light as a circularly polarizing plate.
Here, the image display panel 51 is, for example, an organic EL panel, and displays a desired color image. The image display panel 51 is not limited to the organic EL panel, and various image display panels such as a liquid crystal display panel can be widely applied.

The antireflective film 52 is typically attached to the panel surface of the image display panel 51 by the adhesive layer 53 and held. The antireflection film 52 is configured by integrally laminating a linear polarizing plate 21 and a long liquid crystal film 10 having the characteristics of a λ / 4 wavelength plate by an adhesive layer 22. As the adhesive layer 53, a known adhesive can be used similarly to the adhesive layer 22.

As mentioned above, although the manufacturing method of the long liquid crystal film of this invention, a long polarizing plate, an image display apparatus, and a long liquid crystal film was demonstrated in detail, this invention is not limited to the said embodiment. Various improvements and modifications may be made without departing from the scope of the invention.
For example, the same concept can be applied as a method of suppressing retardation unevenness in a liquid crystal film having retardation in the thickness direction and polarization degree unevenness of a polarizer using orientation of dichroic compound molecules. That is, the in-plane retardation unevenness in the present invention can be appropriately read as thickness direction retardation unevenness or polarization degree unevenness. It will be appreciated by those skilled in the art if the intention of the present specification is understood as to how to design and achieve the various means described in the present invention with respect to the limit of practically allowable unevenness. It is possible.

The invention will now be described in detail by way of examples.

[Preparation of Cellulose Acylate Film 1]
(Preparation of core layer cellulose acylate dope)
The following composition was charged into a mixing tank and stirred to dissolve each component to prepare a cellulose acetate solution to be used as core layer cellulose acylate dope.
── ─ ──
Core Layer Cellulose Acylate Dope ── コ ア ── ──
-Cellulose acetate having an acetyl substitution degree of 2.88 100 parts by mass-Polyester compound B described in the example of JP-A-2015-227955 12 parts by mass-Compound F below 2 parts by mass-Methylene chloride (first solvent) 500 parts by mass · Methanol (second solvent) 75 parts by mass ── ── ──

(Preparation of outer layer cellulose acylate dope)
10 parts by mass of the following matting agent solution was added to 90 parts by mass of the above-mentioned core layer cellulose acylate dope to prepare a cellulose acetate solution to be used as outer layer cellulose acylate dope.
── ─ ──
Matting agent solution ── ── ──
Silica particles having an average particle size of 20 nm (AEROSIL R972, manufactured by Nippon Aerosil Co., Ltd.) 2 parts by mass Methylene chloride (first solvent) 76 parts by mass Methanol (second solvent) 11 parts by mass Core layer cellulose acylate Rate dope 1 mass part ── ── ── ── ──

(Film formation of cellulose acylate film 1)
The core layer cellulose acylate dope and the outer layer cellulose acylate dope are filtered with a filter paper having an average pore diameter of 34 μm and a sintered metal filter having an average pore diameter of 10 μm, and then the core layer cellulose acylate dope and outer layer cellulose acylate dope on both sides thereof And 3 layers were cast simultaneously from a casting port on a 20 ° C. metal band (band casting machine).
Here, at the time of casting, the bead portion was sucked from the upstream side at a suction pressure of -600 Pa.
In addition, the solid content concentration of the core layer cellulose acylate dope at the time of casting is 17.3%.

After casting, the formed film (film) is peeled off from the metal band at a solvent content of about 20% by mass, and both ends in the width direction of the film are fixed with a tenter clip, and the draw ratio in the lateral direction is 1.1 times And dried while stretching. Thereafter, it was further dried by conveying between the rolls of the heat treatment apparatus, and was wound up to prepare a long cellulose acylate film 1 having a thickness of 40 μm. The core layer of the film had a thickness of 36 μm, and the outer layers disposed on both sides of the core layer had a thickness of 2 μm. The in-plane retardation of the obtained cellulose acylate film 1 was 0 nm.
The variation in thickness was measured by sampling at arbitrary five places of 1 m length in the longitudinal direction of the cellulose acylate film. The thickness was measured using an electric micrometer K402B / KG3001A manufactured by Anritsu. As a result, six uneven thickness regions were observed in 1 m length on average. The average value of the maximum film thickness fluctuation (the average thickness and the maximum value of the substrate film thickness difference in the region) in the uneven thickness region was 0.7 μm, and the average length of the uneven thickness region was 60 mm. Therefore, the film thickness slope ΔT was 0.012.

(Film formation of cellulose acylate films 2 to 4)
Long film-like cellulose acylate films 2 to 4 were produced in the same manner as the cellulose acylate film 1 except that the casting conditions were adjusted as shown in Table 1 in the film formation of the cellulose acylate film 1. The in-plane retardation of the obtained cellulose acylate film was all 0 nm.
The cellulose acylate film was pulled out from the roll and sampled at five places of 1 m length in the longitudinal direction at arbitrary intervals to measure the thickness variation in the lateral direction. As a result, from 5 locations, 7 to 7 thickness non-uniform | heterogenous regions were seen in 1 m length on average. The average value of the maximum film thickness fluctuation (the average thickness and the maximum value of the substrate film thickness difference in the region) and the average value of the length of the uneven thickness region were as shown in Table 1.

Example 1
[Production of long liquid crystal film]
Using a production apparatus as shown in FIG. 3, the following composition 1 for photoalignment film was continuously applied by a bar coater on the surface on one side of the produced cellulose acylate film 1. After application, the solvent was removed by drying for 1 minute in a heating zone at 120 ° C. to form a 0.3 μm thick photoisomerization composition layer. Subsequently, while being wound on the mirror-treated back-up roll, a photo alignment film is formed by irradiating polarized ultraviolet light (10 mJ / cm ² , using a super high pressure mercury lamp) so that the polarization axis forms an angle of 45 ° in the longitudinal direction. did.

── ─ ──
Composition for Optical Alignment Film 1
── ─ ──
・ The following polymer Ap3 10 parts by mass ・ The following Nom coat TAB (made by Nisshin Oillio Co., Ltd.) 1.52 parts by mass ・ Multifunctional epoxy compound (Epolide GT401, manufactured by Daicel Corporation)
12.2 parts by mass of thermal acid generator (San Aid SI-60, manufactured by Sanshin Chemical Industry Co., Ltd.)
0.55 parts by mass, butyl acetate 300 parts by mass-------------------------

<Synthesis of Polymer Ap3>
According to the method described in Langmuir, 32 (36), 9245-9253 (2016), using 2-hydroxyethyl methacrylate (HEMA) (Tokyo Kasei's reagent) and the following cinnamic acid chloride derivative, the following monomers m I synthesized -1.

Cinnamic acid chloride derivative

Monomer m-1

In a flask equipped with a condenser, a thermometer and a stirrer, 5 parts by mass of 2-butanone as a solvent was charged, and the flask was heated to reflux with a nitrogen bath flowing at 5 mL / min. Here, 5 parts by mass of monomer m-1, 5 parts by mass of 3,4-epoxycyclohexylmethyl methacrylate (Cyclomer M100, manufactured by Daicel), 2,2'-azobis (isobutyronitrile) as a polymerization initiator A solution prepared by mixing 1 part by mass and 5 parts by mass of 2-butanone as a solvent was added dropwise over 3 hours, and the mixture was further stirred for 3 hours while maintaining the reflux state. After completion of the reaction, the reaction solution was allowed to cool to room temperature, and 30 parts by mass of 2-butanone was added and diluted to obtain a polymer solution of about 20% by mass. The resulting polymer solution is poured into a large excess of methanol to precipitate the polymer, and the collected precipitate is separated by filtration, washed with a large amount of methanol and then air-dried at 50 ° C. for 12 hours, A polymer Ap3 having a photoalignable group was obtained.

Polymer Ap3

ノムコートＴＡＢ

Nom Coat TAB

Subsequently, the following composition 1 for forming an optically anisotropic layer prepared in advance was coated by a die coater on the photoalignment film formed in a long shape, to form a liquid crystal layer (uncured). At this time, the air flow around the die was adjusted to stabilize the coating bead.
The temperature of the coating chamber was 23 ° C. The proportion of cyclopentanone in the coating solution was 28%.

――――――――――――――――――――――――――――――――――――
Coating solution for optically anisotropic layer (Liquid crystal 1)
――――――――――――――――――――――――――――――――――――
Liquid crystal compound L-3 42.00 parts by mass Liquid crystal compound L-4 42.00 parts by mass Polymerizable compound A-1 16.00 parts by mass Polymerization initiator S-1 (oxime type) 0.50 parts by mass, leveling agent (the following compound G-1) 0.20 parts by mass, Hysorb MTEM (manufactured by Toho Chemical Industry Co., Ltd.) 2.00 parts by mass, NK ester A-200 (manufactured by Shin-Nakamura Chemical Co., Ltd.) 1.00 parts by mass · methyl ethyl ketone 305.9 parts by mass · cyclopentanone 118.9 parts by mass------------------------ ―――――
The group adjacent to the acryloyloxy group of the following liquid crystal compounds L-3 and L-4 represents a propylene group (a group in which a methyl group is substituted with an ethylene group), and the following liquid crystal compounds L-3 and L-4 Represents a mixture of regioisomers different in the position of the methyl group.

Liquid crystal compound L-3

Liquid crystal compound L-4

Polymerizable compound A-1

Polymerization initiator S-1

Compound G-1

The formed liquid crystal layer (uncured) was once heated to 110 ° C. in a heating zone, and then cooled to 75 ° C. to stabilize the alignment.
Thereafter, the temperature is maintained at 75 ° C., and the alignment is fixed by ultraviolet irradiation (500 mJ / cm ² , using an ultra-high pressure mercury lamp) in a nitrogen atmosphere (oxygen concentration 100 ppm) to obtain a liquid crystal layer (optical anisotropic layer 2.3 μm thick) ) Was wound on a winding shaft to produce a long liquid crystal film.
The average in-plane retardation Re (550) of the obtained long liquid crystal film satisfies Re (450) / Re (550) <1.0 and 1.0 <Re (650) / Re (550) at 140 nm. The average slow axis was 45 ° to the longitudinal direction.

The film thickness non-uniform area is detected by measuring the film thickness of a portion of the obtained long liquid crystal film where the liquid crystal layer is not coated by using a laser displacement meter and marked, and the phase difference change around the marked area is The in-plane retardation unevenness area was detected by continuously measuring in the transport direction. In addition, when the maximum value of the phase difference fluctuation in the phase difference unevenness area and the length of the in-plane phase difference unevenness area are quantified, the maximum value of the phase difference fluctuation is 0.6 nm, and the length of the in-plane phase difference unevenness area The length was 70 mm. Therefore, the retardation slope ΔRe was 0.009.

[Examples 2 to 6, Comparative Examples 1 to 3]
A long liquid crystal film was produced in the same manner as in Example 1 except that the type of the long base, the temperature of the coating chamber, and the ratio of cyclopentanone in the coating liquid were changed as shown in Table 2.
When the maximum value of the retardation variation of the obtained long liquid crystal film and the length of the in-plane retardation variation region are quantified, the maximum value of the retardation variation, the length of the in-plane retardation variation region, the retardation inclination ΔRe Is as shown in Table 2.

[Evaluation]
In order to evaluate the variation (individual difference) of the liquid crystal film cut out from the produced long liquid crystal film, the cut out liquid crystal film was incorporated in a display device, and the dispersion of the displayed image was observed.

[Production of Display Device]
<Formation of Positive C Plate>
A positive C plate was formed on the produced long liquid crystal film.

(Formation of alignment film)
The surface of the long liquid crystal film on the liquid crystal layer side was subjected to corona treatment, and an alignment film coating solution (B) having the following composition was continuously applied using a # 14 wire bar. Thereafter, the long liquid crystal film coated with the alignment film coating solution (B) was dried with warm air at 60 ° C. for 60 seconds and further with warm air at 100 ° C. for 120 seconds to form an alignment film.

Composition of Alignment Film Coating Solution (B)----------------------
The following modified polyvinyl alcohol-2 10 parts by weight water 371 parts by weight methanol 119 parts by weight glutaraldehyde (crosslinking agent) 0.5 parts by weight citric acid ester (manufactured by Sankyo Chemical Co., Ltd. AS3) 0.175 parts by weight photopolymerization initiator (IRGACURE 2959, manufactured by Ciba Japan) 2.0 parts by mass -------------------------------------

Modified polyvinyl alcohol-2

An optically anisotropic layer coating solution (C) containing a rod-like liquid crystal compound having the following composition was continuously coated on the produced alignment film with a # 5.0 wire bar. The film transport speed (V) was 26 m / min. For drying of the solvent of the coating solution and orientation ripening of the rod-like liquid crystal compound, the film coated with the optically anisotropic layer coating solution (C) was heated with a hot air of 60 ° C. for 60 seconds. Thereafter, the obtained film was subjected to UV (ultraviolet light) irradiation at 60 ° C. to fix the alignment of the rod-like liquid crystal compound, thereby producing a positive C plate.
The thickness of the positive C plate was 0.7 μm, and Rth (550) was -70 nm.

Composition of Optically Anisotropic Layer Coating Liquid (C)-----------------------
-Rod-like liquid crystal compound-80 parts by mass-Rod-like liquid crystal compound-20 parts by mass-Photopolymerization initiator (IRGACURE 907, manufactured by Ciba Japan) 3 parts by mass-Sensitizer (Kayacure DETX, Nippon Kayaku (stock Made of 1) mass part-Fluorinated compound (FP-2) 0.3 mass part-Alignment film interface alignment agent-0.55 mass part-methyl ethyl ketone 193 mass part----------- ―――――――――――――――――――――――――

Rod-like liquid crystal compound-1

Rod-like liquid crystal compound-2

Fluorine-containing compound (FP-2)

<Production of a long polarizing plate>
(Preparation of linear polarizer and polarizer protective film)
An 80 μm thick polyvinyl alcohol (PVA) film was dyed by being immersed in an aqueous iodine solution having an iodine concentration of 0.05% by mass at 30 ° C. for 60 seconds. Then, after the dyed PVA film is longitudinally stretched to 5 times the original length while immersed in a boric acid aqueous solution having a boric acid concentration of 4% by mass for 60 seconds, the obtained film is subjected to 4 at 50 ° C. After drying for a minute, a 20 μm thick polarizer was obtained.
A commercially available cellulose acylate film "TD 40 UC" (manufactured by Fujifilm Corporation) is prepared, and the cellulose acylate film is immersed in an aqueous solution of sodium hydroxide at 55 ° C. at 1.5 mol / liter, and then cellulose acylate is produced. The sodium hydroxide on the system film was thoroughly washed away with water. Thereafter, the obtained cellulose acylate film was immersed in a dilute sulfuric acid aqueous solution at 35 ° C. for 1 minute at 0.005 mol / liter, and then immersed in water to wash away the dilute sulfuric acid aqueous solution sufficiently. Thereafter, the obtained cellulose acylate film was sufficiently dried at 120 ° C. to prepare a polarizer protective film.

(Lamination of linear polarizer and long liquid crystal film)
The long liquid crystal film having the positive C plate was saponified.
The polarizer protective film prepared above is bonded to one side of the linear polarizer prepared above, and the other side is saponified with the long liquid crystal film so that the long substrate side is in contact with the linear polarizer. It stuck together with a system adhesive. Thus, a long polarizing plate having a linear polarizer, a long liquid crystal film, and a positive C plate was produced. This long polarizing plate is a circularly polarizing plate.

<Production of Display Device>
From the produced long polarizing plate, 10 circular polarizing plates of 6 inch size were cut out so that positions do not overlap in the longitudinal direction and the width direction.
Each of the cut out circular polarizers is disassembled into GALAXY SII manufactured by SAMSUNG equipped with organic EL panel, peeled off the circular polarizer, and pasted through SK2057 (made by Soken Chemical Co., Ltd.) so that the positive C plate side becomes the panel side. Then, corresponding display devices were manufactured.

<Evaluation of individual differences>
The display device produced ten each for each Example and comparative example was observed under a fluorescent lamp, and the individual difference of the front color tone of the display within the same Example and comparative example was evaluated by the following criteria.
A: Individual differences can not be recognized.
B: Although slight individual differences can be confirmed, there is no problem in practical use.
C: Individual differences can be recognized, causing problems in practical use.
D: Individual differences can be clearly confirmed.

<Evaluation of in-plane unevenness>
The display device was observed under a fluorescent lamp for each example and comparative example to evaluate whether or not front color unevenness was recognized in the plane, and the result was judged as follows.
A: In-plane unevenness can not be recognized.
B: Although slight in-plane unevenness can be confirmed, there is no problem in practical use.
C: In-plane unevenness can be recognized, causing a problem in practical use.
D: In-plane unevenness can be clearly confirmed.
The results are shown in Table 2.

From the results of Table 2, the in-plane unevenness of the cut out liquid crystal film and the long liquid crystal film of the present invention having a retardation inclination ΔRe in the range of 0.002 to 0.018 (nm / mm) are compared with the comparative example. It turns out that individual differences are small.
Further, it is understood from the comparison of Examples 1 to 6 that the retardation slope ΔRe is more preferably 0.015 (nm / mm) or less.
Further, from Table 1 and Table 2, it is preferable that the film thickness gradient ΔT of the long base material is 0.025 (μm / mm) or less, and more preferably 0.020 (μm / mm) or less I understand.
Moreover, it is understood from Table 2 that the maximum value of the retardation variation is preferably 1.2 nm or less, and more preferably 0.9 nm or less.
In addition, for a long liquid crystal film having a small retardation inclination ΔRe, using a long base having a small film thickness inclination ΔT (0.005 to 0.025 (μm / mm)), and a coating liquid to be a liquid crystal layer It can be seen that when applying a solution, it can be produced by suppressing the variation in the thickness of the coating solution layer by various methods.

DESCRIPTION OF SYMBOLS 1 long base material 2 orientation layer 3 liquid crystal layer 10 long liquid crystal film 20 polarizing plate 21 linear polarizer 22 adhesion layer 30 manufacturing apparatus of long liquid crystal film 31 base material roll 32, 35 application part 33, 36 heating part 34, 37 light source 38 backup roll 39 liquid crystal film roll 40 laminating apparatus 41 peel film 42 polarizer roll 43 peel roll 44 peel film roll 45 pressure roll 46 polarizing plate roll 50 image display device 51 image display panel 52 antireflection film 53 adhesive layer 60 , 64, 68 rotating shaft 62, 66, 70 winding shaft

Claims (11)

A long liquid crystal film comprising at least a long base material and a long liquid crystal layer having in-plane retardation,
The long base has a plurality of strip-like thickness unevenness areas extending in the width direction, in the longitudinal direction,
The liquid crystal layer has a band-like in-plane retardation unevenness area extending in the width direction of the long base material at the position of the thickness unevenness area in the plane direction,
The long liquid crystal film, wherein the retardation slope ΔRe of the in-plane retardation unevenness region is in the range of 0.002 to 0.018 (nm / mm). The film thickness gradient ΔT of the elongated substrate is in the range of 0.005 to 0.025 (μm / mm) within a strip-shaped uneven thickness region extending in the width direction of the elongated substrate. The long liquid crystal film described in 1. The long liquid crystal film according to claim 1, comprising a long light alignment layer between the long base and the long liquid crystal layer. The long liquid crystal film according to claim 3, wherein the liquid crystal layer is provided so as to be peelable between the light alignment layer and the liquid crystal layer, or between the long base and the light alignment layer. . The long liquid crystal layer according to any one of claims 1 to 4, wherein the liquid crystal layer is a λ / 4 wavelength plate, and the slow axis thereof forms 45 ° with the longitudinal direction of the long base material. Liquid crystal film. The long liquid crystal film according to any one of claims 1 to 5, wherein the liquid crystal layer satisfies the following formula.
Re (450) <Re (550) <Re (650)
0.03 <Δn (550) <0.20 The long liquid crystal film according to any one of claims 1 to 6, wherein an in-plane retardation Re of the long base is 5 nm or less. A long liquid crystal film according to any one of claims 1 to 7;
A long polarizing plate having a long linear polarizer laminated on the long liquid crystal film. The image display apparatus containing the polarizing plate cut out from the elongate polarizing plate of Claim 8. A method for producing a long liquid crystal film, wherein a long liquid crystal layer is provided on a long base material,
Preparing a long base roll having a plurality of streaky uneven thickness regions extending in the width direction in the longitudinal direction;
While sequentially feeding the long base material from the long base material roll in the longitudinal direction,
An orientation step of applying an orientation regulating force to the elongated base in an elongated manner;
An applying step of applying the polymerizable liquid crystal composition in an elongated form to the region of the elongated base material to which the alignment control force is applied;
After a coating liquid layer formed by coating is subjected to an alignment treatment, it is cured to fix the alignment state, and a liquid crystal layer forming step of forming the liquid crystal layer, and
And winding the long liquid crystal film in which the liquid crystal layer and the long base material are laminated in a roll shape,
In the application step, a means for adjusting the thickness of the coating liquid layer laminated on the long base material to a constant level is provided, and the variation of the thickness of the liquid crystal layer is within ± 2% of the average thickness. A method of producing a long liquid crystal film characterized in that The method for producing a long liquid crystal film according to claim 10, wherein an in-plane retardation Re of the long base is 5 nm or less.

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