WO2024062850A1

WO2024062850A1 - Optical film, method for producing optical film, polarizing plate, and image display device

Info

Publication number: WO2024062850A1
Application number: PCT/JP2023/031117
Authority: WO
Inventors: 悠太福島; 智則三村; 慎平吉田; 勇太高橋
Original assignee: 富士フイルム株式会社
Priority date: 2022-09-22
Filing date: 2023-08-29
Publication date: 2024-03-28

Abstract

The present invention addresses the problem of providing: an optical film which has improved alignment of a liquid crystal compound in an optically anisotropic layer and which is prevented from the occurrence of bright spot defects; a method for producing an optical film; a polarizing plate; and an image display device. The optical film according to the present invention comprises a support and an optically anisotropic layer which are located adjacent to each other, in which the optically anisotropic layer is a layer formed using an optically anisotropic layer-forming composition containing a polymerizable liquid crystal compound, the support contains a surfactant having a hydrophilic group and a hydrophobic group, and the hydrophobic group is at least one group selected from the group consisting of an alkyl group having 5 to 29 carbon atoms, a silicon-containing group, and a fluorine-containing group.

Description

Optical film, optical film manufacturing method, polarizing plate, and image display device

The present invention relates to an optical film, a method for manufacturing an optical film, a polarizing plate, and an image display device.

Optical films such as optical compensatory sheets and retardation films are used in various image display devices to eliminate image coloration or expand viewing angles.
A stretched birefringent film has been used as an optical film, but in recent years, it has been proposed to use an optical film having an optically anisotropic layer made of a liquid crystal compound instead of the stretched birefringent film.

When forming such an optically anisotropic layer, an alignment film is usually used.
For example, Patent Document 1 describes an embodiment in which an optically anisotropic layer is formed on an alignment film formed using a coating liquid containing polyvinyl alcohol having a specific group ([Claim 1] [ Claim 2] [Example]).

Japanese Patent Application Publication No. 9-152509

In order to reduce the thickness and simplify the manufacturing process, the present inventors applied a rubbing treatment to the support (base material) and created an optical structure in which the support and the optically anisotropic layer were adjacent to each other without using an alignment film. When we investigated the production of the film, it was found that the orientation of the liquid crystal compound in the optically anisotropic layer was good, but debris from the support was scattered during the rubbing process, and the debris caused optical anisotropy. It was clarified that bright spot defects may occur in optical films having a transparent layer.

Therefore, an object of the present invention is to provide an optical film in which the orientation of a liquid crystal compound in an optically anisotropic layer is improved and the occurrence of bright spot defects is suppressed.
Another object of the present invention is to provide a method for manufacturing an optical film, a polarizing plate, and an image display device.

As a result of intensive studies to achieve the above object, the present inventors found that by using a support containing a surfactant having a hydrophilic group and a specific hydrophobic group, the liquid crystal compound in the optically anisotropic layer can be improved. The present inventors have discovered that the orientation of the optical film can be improved and the occurrence of bright spot defects in optical films can be suppressed, and the present invention has been completed.
That is, the present inventors have found that the above problem can be solved by the following configuration.

[1] An optical film having a support and an optically anisotropic layer adjacent to each other,
The optically anisotropic layer is a layer formed using an optically anisotropic layer forming composition containing a polymerizable liquid crystal compound,
the support contains a surfactant having a hydrophilic group and a hydrophobic group,
An optical film in which the hydrophobic group is at least one group selected from the group consisting of an alkyl group having 5 to 29 carbon atoms, a silicon-containing group, and a fluorine-containing group.
[2] The optically anisotropic layer is a layer in which the orientation state of the polymerizable liquid crystal compound is fixed,
The optical film according to [1], wherein the orientation state is homogeneous orientation or twisted orientation.
[3] The optical film according to [1] or [2], wherein the support is a cellulose acylate film.
[4] The optical film according to any one of [1] to [3], wherein the hydrophilic group possessed by the surfactant is an ionic hydrophilic group.
[5] The optical film according to any one of [1] to [4], wherein the hydrophilic group possessed by the surfactant is an anionic hydrophilic group.
[6] The optical film according to any one of [1] to [5], wherein the surfactant is a polymer compound.
[7] The optical film according to any one of [1] to [6], wherein the hydrophobic group of the surfactant is an alkyl group having 12 to 18 carbon atoms.
[8] A support production step of producing the support according to [1],
a rubbing process of applying a rubbing treatment to the support;
an optically anisotropic layer forming step of forming an optically anisotropic layer on a rubbed support using an optically anisotropic layer forming composition containing a polymerizable liquid crystal compound;
A method for producing an optical film, comprising:
[9] The method for producing an optical film according to [8], wherein the support preparation step includes a step of casting a dope containing the surfactant according to [1].
[10] The optical film according to [8] or [9], wherein the support preparation step includes a step of impregnating the surface of the polymer film with the composition containing the surfactant and solvent according to [1]. Production method.
[11] A polarizing plate comprising the optical film according to any one of [1] to [7] and a polarizer.
[12] An image display device comprising the optical film according to any one of [1] to [7].
[13] The image display device according to [12], which is a liquid crystal display device.
[14] The image display device according to [12], which is an organic electroluminescence display device.

According to the present invention, it is possible to provide an optical film in which the alignment of the liquid crystal compound in the optically anisotropic layer is excellent and the occurrence of bright spot defects is suppressed.
Furthermore, according to the present invention, it is possible to provide a method for producing an optical film, a polarizing plate, and an image display device.

The present invention will be described in detail below.
The following description of the components may be based on representative embodiments of the present invention, but the present invention is not limited to such embodiments.
In this specification, a numerical range expressed using "to" means a range that includes the numerical values before and after "to" as the lower and upper limits.
In the present specification, each component may be used alone or in combination of two or more substances corresponding to each component. When two or more substances are used in combination for each component, the content of the component refers to the total content of the substances used in combination, unless otherwise specified.
In addition, in this specification, "(meth)acrylate" is a notation representing "acrylate" or "methacrylate", "(meth)acrylic" is a notation representing "acrylic" or "methacrylic", and "(meth)acryloyl" is a notation representing "acryloyl" or "methacryloyl".

[Optical film]
The optical film of the present invention has a support and an optically anisotropic layer adjacent to each other.
Further, the optically anisotropic layer included in the optical film of the present invention is a layer formed using an optically anisotropic layer forming composition containing a polymerizable liquid crystal compound.
Further, the support of the optical film of the present invention contains a surfactant having a hydrophilic group and a hydrophobic group, and the hydrophobic group of the surfactant has 5 to 29 carbon atoms. It is at least one group selected from the group consisting of an alkyl group, a silicon-containing group, and a fluorine-containing group (hereinafter also abbreviated as "specific hydrophobic group"). In addition, in the following description, the surfactant having a hydrophilic group and a specific hydrophobic group is also abbreviated as "specific surfactant."

In the present invention, as described above, by using a support containing a specific surfactant, the orientation of the liquid crystal compound in the optically anisotropic layer is improved, and the occurrence of bright spot defects in the optical film is suppressed. can.
The reason why these effects occur is not clear in detail, but the present inventors speculate as follows.
In other words, by using a support containing a specific surfactant, the friction between the pile of the rubbing cloth used when rubbing the support and the support is reduced, and the amount of dust generated from the support is reduced. It is thought that the occurrence of bright spot defects could be suppressed because the bright spot defects could be reduced.
In addition, since the specific surfactant has a specific hydrophobic group, compatibility with the main component of the support is maintained, and while the specific surfactant is uniformly present on the support surface, Since the surface is not completely covered with the specific surfactant and can be left in a moderately exposed state, the orientation of the liquid crystal compound in the optically anisotropic layer formed on the support is improved. It is thought that
Hereinafter, the alignment film and the optically anisotropic layer included in the optical film of the present invention will be explained in detail.

[Support]
The support possessed by the optical film of the present invention is a support containing a specific surfactant.
Here, in the present invention, the support refers to a base material containing the components of the support, and for example, when forming the optically anisotropic layer described later, some of the components of the optically anisotropic layer are When the mixture penetrates into the support and forms a mixed layer of the components of the support and the components of the optically anisotropic layer, the mixed layer is a layer included in the support.

The type of support is not particularly limited, and any known support can be used. In particular, a transparent support is preferred. Note that the transparent support is intended to be a support having a visible light transmittance of 60% or more, and the transmittance is preferably 80% or more, more preferably 90% or more.

A polymer film is preferred as the support.
Examples of polymer films include cellulose acylate films (e.g., cellulose triacetate films, cellulose diacetate films, cellulose acetate butyrate films, cellulose acetate propionate films), polyacrylic resin films such as polymethyl methacrylate, polyethylene, polypropylene, etc. Polyolefins, polyester resin films such as polyethylene terephthalate and polyethylene naphthalate, polyether sulfone films, polyurethane resin films, polyester films, polycarbonate films, polysulfone films, polyether films, polymethyl pentene films, polyether ketone films, ( Examples include meth) acrylonitrile film, polyolefin, polymers with alicyclic structure (norbornene resin (Arton: trade name, manufactured by JSR Corporation), amorphous polyolefin (Zeonex: trade name, manufactured by Nippon Zeon Corporation)), etc. It will be done.
Among these, cellulose acylate film is preferred as the support because it provides better orientation of the liquid crystal compound in the optically anisotropic layer.
Further, the support may be removable.

The thickness of the support is preferably 20 to 100 μm, more preferably 25 to 60 μm.

<Specific surfactant>
The specific surfactant contained in the support is a surfactant having a hydrophilic group and a specific hydrophobic group.

(Specific hydrophobic group)
As mentioned above, the specific hydrophobic group possessed by the specific surfactant is at least one group selected from the group consisting of an alkyl group having 5 to 29 carbon atoms, a silicon-containing group, and a fluorine-containing group.

Examples of the alkyl group include pentyl group, hexyl group, heptyl group, octyl group, 2-ethylhexyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, hexadecyl group (cetyl group), Examples include octadecyl group, icosyl group, docosyl group, tetracosyl group, hexacosyl group, nonacosyl group, and the like.
In addition, although the said alkyl group may be a linear alkyl group and a branched alkyl group may be sufficient as it, it is preferable that it is a linear alkyl group.

Examples of the silicon-containing group include a group represented by the following formula (S-1).
Formula (S-1) -Si(Ra)x(Rb)y
Here, Ra represents a hydroxyl group or a hydrolyzable group. Rb represents a non-hydrolyzable group. x represents an integer from 1 to 3, y represents an integer from 0 to 2, and the relationship x+y=3 is satisfied.
The hydrolyzable group represents a group that can generate a silanol group or a group that can form a siloxane condensate, and specifically includes a halogen group, an alkoxy group, an acyloxy group, an isocyanate group, etc. . Among these, an alkoxy group (preferably having 1 to 2 carbon atoms) is preferred.
Examples of the non-hydrolyzable group include a hydrogen atom, an aliphatic hydrocarbon group such as an alkyl group, an alkenyl group, and an alkynyl group, an aromatic hydrocarbon group such as an aryl group, or a combination thereof. .

The fluorine-containing group may, for example, be an alkyl group containing a fluorine atom, and specifically, a suitable example is a group represented by the following formula (F-1).
Formula (F-1) -La-Cf
Here, Cf represents a fluorine atom-containing alkyl group. The fluorine atom-containing alkyl group represents an alkyl group containing a fluorine atom, and is preferably a perfluoroalkyl group.
The number of carbon atoms in the fluorine atom-containing alkyl group is not particularly limited, and is preferably 1 to 30, more preferably 3 to 20, and even more preferably 5 to 10, for the reason that the alignment of the liquid crystal compound in the optically anisotropic layer is improved.
The number of fluorine atoms contained in the fluorine atom-containing alkyl group is not particularly limited, and is preferably 1 to 30, more preferably 5 to 25, and even more preferably 10 to 20, because this improves the alignment of the liquid crystal compound in the optically anisotropic layer.
Furthermore, La represents a single bond or a divalent linking group.
Examples of the divalent linking group represented by one embodiment of La include a divalent hydrocarbon group which may have a substituent, a divalent heterocyclic group which may have a substituent, -O-, -S-, -N(Q)-, -CO-, or a combination thereof. Q represents a hydrogen atom or a substituent.
Examples of the divalent hydrocarbon group include divalent aliphatic hydrocarbon groups such as alkylene groups having 1 to 10 carbon atoms, alkenylene groups having 1 to 10 carbon atoms, and alkynylene groups having 1 to 10 carbon atoms, and divalent aromatic hydrocarbon groups such as arylene groups.
Examples of the divalent heterocyclic group include a divalent aromatic heterocyclic group, and specific examples thereof include a pyridylene group (pyridine-diyl group), a pyridazine-diyl group, an imidazole-diyl group, a thienylene group (thiophene-diyl group), and a quinolylene group (quinoline-diyl group).
Examples of groups combining these include groups combining at least two or more selected from the group consisting of the above-mentioned divalent hydrocarbon groups, divalent heterocyclic groups, -O-, -S-, -N(Q)-, and -CO-. Examples include -O-divalent hydrocarbon group-, -divalent hydrocarbon group -O-, and -divalent hydrocarbon group -N(Q)-.
L ¹ is preferably a divalent linking group combining at least two or more groups selected from the group consisting of a linear alkylene group having 1 to 10 carbon atoms which may have a substituent, a branched alkylene group having 3 to 10 carbon atoms which may have a substituent, a cyclic alkylene group having 3 to 10 carbon atoms which may have a substituent, an arylene group having 6 to 12 carbon atoms which may have a substituent, -O-, and -N(Q)-, and more preferably a divalent linking group combining at least two or more groups selected from the group consisting of a linear alkylene group having 1 to 10 carbon atoms which may have a substituent, a cyclic alkylene group having 3 to 10 carbon atoms which may have a substituent, -O-, and -NH-.
In addition, examples of the substituent that the above-mentioned divalent hydrocarbon group (including an alkylene group) and divalent heterocyclic group may have, as well as the substituent represented by one embodiment of Q, include a halogen atom, an alkyl group, an alkoxy group, an aryl group, an aryloxy group, a cyano group, a carboxy group, an alkoxycarbonyl group, and a hydroxyl group.

In the present invention, the specific hydrophobic group is preferably an alkyl group having 5 to 29 carbon atoms, more preferably an alkyl group having 10 to 25 carbon atoms. For the reason that it is suppressed, an alkyl group having 12 to 18 carbon atoms is more preferable.

(hydrophilic group)
The hydrophilic group possessed by the specific surfactant is not particularly limited, and both ionic hydrophilic groups (anionic hydrophilic groups, cationic hydrophilic groups, amphoteric hydrophilic groups) and nonionic hydrophilic groups can be used.
Examples of the anionic hydrophilic group include a hydroxy group, a carboxy group, a carboxylate, a sulfonic acid group, a sulfonate, a sulfate, a phosphoric acid group, and a phosphoric acid ester salt.
Examples of the cationic hydrophilic group include an amino group and a quaternary ammonium salt.
The nonionic hydrophilic group may be any of an ester type, an ether type, an ester-ether type, and an alkanolamide type, and is preferably an ether type, and more preferably a polyoxyalkylene group (e.g., a polyoxyethylene group, a polyoxypropylene group, a polyoxyalkylene group in which an oxyethylene group and an oxypropylene group are blocked or randomly bonded, etc.).

Among these hydrophilic groups, the reason why the orientation of the liquid crystal compound in the optically anisotropic layer is better and the generation of bright spot defects in the optical film can be further suppressed (hereinafter referred to as "the effect of the present invention is better") (also abbreviated as "excellent reason"), an ionic hydrophilic group is preferable, and an anionic hydrophilic group is more preferable.

In the present invention, the specific surfactant may be a low molecular compound or a high molecular compound.
Here, the term "low molecular compound" refers to a specific surfactant having a molecular weight of 100 or more and less than 2,000.
Furthermore, the term "polymer compound" refers to a specific surfactant with a molecular weight of 2000 or more, and the weight average molecular weight (Mw) is preferably 5000 to 40000, more preferably 8000 to 39000. , more preferably from 10,000 to 35,000. When the weight average molecular weight is 10,000 or more, unevenness is suppressed during formation of the optically anisotropic layer, and when the weight average molecular weight is 40,000 or less, the orientation of the liquid crystal compound in the optically anisotropic layer becomes better.

Furthermore, in the present invention, the specific surfactant is preferably a polymer compound because the effects of the present invention are more excellent.

Among the specific surfactants, specific examples of low molecular weight compounds include sodium dodecyl sulfate, polyoxyethylene (10) cetyl ether, polyoxyethylene (20) docosyl ether, tetrahexylammonium bromide, and tetra- Examples include n-octylammonium bromide, trimethylstearylammonium bromide, melisic acid, and the like.

Among the specific surfactants, examples of high molecular compounds include polymers having the above-mentioned specific hydrophobic group and hydrophilic group in the side chains of (meth)acrylic polymers.
Such polymers include a side chain having the above-mentioned specific hydrophobic group (hereinafter also abbreviated as "hydrophobic part") and a side chain having the above-mentioned hydrophilic group (hereinafter also abbreviated as "hydrophilic part"). ) in separate repeating units is preferred.
Here, the hydrophobic part is not particularly limited as long as it has the above-mentioned specific hydrophobic group, but it has a polyoxyalkylene group as a linking group on the main chain side and an alkyl group having 12 to 22 carbon atoms on the terminal side. Those having groups are preferred.
Further, the hydrophilic part is not particularly limited as long as it has the above-mentioned hydrophilic group, but it is preferably a side chain having a polyoxyalkylene group, more preferably a side chain having a polyoxyethylene group. preferable.

Examples of monomers that form such a hydrophobic part include those shown below. In addition, in the following formula, n represents an integer of 2 to 50.

Furthermore, examples of monomers that form such a hydrophilic part include those shown below. In addition, in the following formula, n represents an integer of 2 to 50.

In the present invention, the content of the specific surfactant contained in the support is preferably 0.1 to 20% by mass, and preferably 0.2 to 10% by mass based on the total mass of the support. is more preferable, and even more preferably 0.3 to 5% by mass.

Furthermore, in the present invention, at least a part of the specific surfactant contained in the support is contained in a region (hereinafter referred to as (abbreviated as "surface layer region") is preferable.
Here, the presence of the specific surfactant in the surface layer region of the support can be confirmed by, for example, time-of-flight secondary ion mass spectrometry (TOF-SIMS). As the TOF-SIMS method, the method described in "Surface Analysis Technology Selection - Secondary Ion Mass Spectrometry" edited by the Japan Surface Science Society, Maruzen Co., Ltd. (published in 1999) can be adopted.
Specifically, analysis is performed by repeating ion beam irradiation and TOF-SIMS measurement from the interface on the optically anisotropic layer side of the support. In addition, ion beam irradiation and TOF-SIMS measurements are performed after component analysis of a region from the surface to 1 to 2 nm in the thickness direction (hereinafter referred to as the "surface region"), and then 1 to several hundred nm in the thickness direction. Dig deeper and repeat the series of operations to analyze the composition of the next surface area.
Then, the distribution of the specific surfactant in the thickness direction of the support is analyzed by measuring the secondary ion strength derived from the hydrophilic group and the specific hydrophobic group.
Examples of the type of ion beam include an ion beam using an argon gas cluster ion gun (Ar-GCIB gun).

[Optical anisotropic layer]
The optically anisotropic layer of the optical film of the present invention is a layer provided adjacent to the above-mentioned support, and in the present invention, it is a layer formed by using an optically anisotropic layer-forming composition containing a polymerizable liquid crystal compound. More specifically, as described in detail in the optically anisotropic layer-forming step of the optically anisotropic layer-forming method of the present invention described later, it is preferable that the layer is formed by orienting the polymerizable liquid crystal compound in the coating film formed by applying the optically anisotropic layer-forming composition and fixing the state, and in this case, it is no longer necessary to show liquid crystallinity after becoming a layer.

<Polymerizable liquid crystal compound>
The polymerizable liquid crystal compound contained in the composition for forming an optically anisotropic layer is a liquid crystal compound having a polymerizable group.
Here, the polymerizable group is not particularly limited, but preferably a polymerizable group capable of radical polymerization or cationic polymerization.
As the radically polymerizable group, a known radically polymerizable group can be used, and preferred examples include an acryloyloxy group or a methacryloyloxy group. In this case, it is known that an acryloyloxy group generally has a high polymerization rate, and an acryloyloxy group is preferred from the viewpoint of improving productivity, but a methacryloyloxy group can also be used as a polymerizable group.
As the cationic polymerizable group, a known cationic polymerizable group can be used, and specifically, an alicyclic ether group, a cyclic acetal group, a cyclic lactone group, a cyclic thioether group, a spiro-orthoester group, and a vinyloxy Examples include groups. Among these, an alicyclic ether group or a vinyloxy group is preferred, and an epoxy group, an oxetanyl group, or a vinyloxy group is particularly preferred.
Particularly preferred examples of polymerizable groups include polymerizable groups represented by any of the following formulas (P-1) to (P-20).

The polymerizable liquid crystal compound is not particularly limited, and includes, for example, a compound capable of homeotropic alignment, homogeneous alignment, twisted alignment, hybrid alignment, and cholesteric alignment.
Generally, liquid crystal compounds can be classified into rod-like types and disc-like types based on their shapes. Furthermore, there are low-molecular and high-molecular types, respectively. Polymers generally refer to those with a degree of polymerization of 100 or more (Polymer Physics/Phase Transition Dynamics, Masao Doi, p. 2, Iwanami Shoten, 1992). In the present invention, any liquid crystal compound can be used, but a rod-like liquid crystal compound or a discotic liquid crystal compound (discotic liquid crystal compound) is preferable. Further, a monomer or a relatively low molecular weight liquid crystal compound having a degree of polymerization of less than 100 is preferable.

As the rod-shaped liquid crystal compound, for example, those described in claim 1 of Japanese Patent Publication No. 11-513019 or paragraphs [0026] to [0098] of JP-A-2005-289980 are preferable, and as the discotic liquid crystal compound, For example, those described in paragraphs [0020] to [0067] of JP-A-2007-108732 or paragraphs [0013] to [0108] of JP-A-2010-244038 are preferred.

As the polymerizable liquid crystal compound, a reverse wavelength dispersion liquid crystal compound can be used.
Here, in this specification, a liquid crystal compound with "reverse wavelength dispersion" refers to the in-plane retardation (Re) value measured at a specific wavelength (visible light range) of a retardation film produced using this compound. In other words, as the measurement wavelength becomes larger, the Re value becomes the same or becomes higher.

The reverse wavelength dispersion liquid crystal compound is not particularly limited as long as it can form a reverse wavelength dispersion film as described above. (especially the compounds described in paragraphs [0034] to [0039]), the compounds represented by the general formula (1) described in JP-A-2010-084032 (especially the compounds described in paragraphs [0067] to [0073]) ), and the compound represented by the general formula (1) described in JP-A-2016-081035 (particularly the compounds described in paragraphs [0043] to [0055]).
Furthermore, paragraphs [0027] to [0100] of JP2011-006360, paragraphs [0028] to [0125] of JP2011-006361, and paragraphs [0034] to [0034] of JP2012-207765. 0298], paragraphs [0016] to [0345] of JP2012-077055, paragraphs [0017] to [0072] of WO12/141245, paragraphs [0021] to [0088] of WO12/147904, Examples include compounds described in paragraphs [0028] to [0115] of WO14/147904.

<Polymerization initiator>
The composition for forming an optically anisotropic layer preferably contains a polymerization initiator.
Examples of the polymerization initiator include those explained in connection with the composition for forming an alignment film mentioned above.

<Solvent>
The composition for forming an optically anisotropic layer preferably contains a solvent from the viewpoint of workability when forming an optically anisotropic layer.
Examples of solvents include ketones (e.g., acetone, 2-butanone, methyl isobutyl ketone, cyclopentanone, and cyclohexanone), ethers (e.g., dioxane, and tetrahydrofuran), aliphatic hydrocarbons (e.g., hexane), cycloaliphatic hydrocarbons (e.g. cyclohexane), aromatic hydrocarbons (e.g. toluene, xylene, and trimethylbenzene), halogenated carbons (e.g. dichloromethane, dichloroethane, dichlorobenzene, and chloro toluene), esters (e.g. methyl acetate, ethyl acetate, and butyl acetate), water, alcohols (e.g. ethanol, isopropanol, butanol, and cyclohexanol), cellosolves (e.g. methyl cellosolve, and ethyl cellosolve), cellosolve acetates, sulfoxides (eg, dimethyl sulfoxide), amides (eg, dimethylformamide, and dimethylacetamide).

<Leveling agent>
The composition for forming an optically anisotropic layer preferably contains a leveling agent from the viewpoint of keeping the surface of the optically anisotropic layer smooth and facilitating orientation control.
As such a leveling agent, a fluorine-based leveling agent or a silicon-based leveling agent is preferable because it has a high leveling effect with respect to the amount added, and a fluorine-based leveling agent is more preferable because it is less likely to cause weeping (bloom, bleed). .
Examples of the leveling agent include compounds described in paragraphs [0079] to [0102] of JP-A No. 2007-069471, and compounds represented by the general formula (I) described in JP-A No. 2013-047204. (especially the compounds described in paragraphs [0020] to [0032]), compounds represented by the general formula (I) described in JP-A-2012-211306 (especially the compounds described in paragraphs [0022] to [0029]) (compounds described in JP-A No. 2002-129162), liquid crystal alignment promoters represented by general formula (I) described in JP-A No. 2002-129162 (particularly in paragraphs [0076] to [0078] and [0082] to [0084] compounds represented by general formulas (I), (II) and (III) described in JP-A No. 2005-099248 (particularly those described in paragraphs [0092] to [0096] compounds), etc. Note that the leveling agent may also have a function as an alignment control agent, which will be described later.

<Orientation control agent>
The composition for forming an optically anisotropic layer may contain an alignment control agent, if necessary.
By using an orientation control agent, various orientation states such as homogeneous orientation, homeotropic orientation, tilted orientation, twisted orientation, hybrid orientation, and cholesteric orientation can be formed, and specific orientation states can be controlled more uniformly and more precisely. It can be realized by

As the alignment control agent that promotes homogeneous alignment, for example, a low-molecular alignment control agent and a polymeric alignment control agent can be used.
Examples of low-molecular orientation control agents include paragraphs [0009] to [0083] of JP-A No. 2002-20363, paragraphs [0111] to [0120] of JP-A No. 2006-106662, and paragraphs [0111] to [0120] of JP-A No. 2006-106662, and JP-A No. 2012-2012. The descriptions in paragraphs [0021] to [0029] of Publication No.-211306 can be referred to, and the contents thereof are incorporated into the present specification.
For polymer alignment control agents, please refer to paragraphs [0021] to [0057] of JP-A No. 2004-198511 and paragraphs [0121] to [0167] of JP-A No. 2006-106662, for example. and the contents thereof are incorporated herein.

Furthermore, examples of the alignment control agent that forms or promotes homeotropic alignment include boronic acid compounds and onium salt compounds. Examples of this alignment control agent include paragraphs [0023] to [0032] of JP-A No. 2008-225281, paragraphs [0052]-[0058] of JP-A No. 2012-208397, and paragraphs [0052] to [0058] of JP-A No. 2008-026730. The compounds described in paragraphs [0024] to [0055] and paragraphs [0043] to [0055] of JP-A-2016-193869 can be referred to, and the contents thereof are incorporated into the present specification.

On the other hand, cholesteric alignment can be achieved by adding a chiral agent to the composition for forming an optically anisotropic layer, and the direction of rotation of the cholesteric alignment can be controlled depending on the direction of the chirality.
Note that the pitch of cholesteric alignment may be controlled depending on the alignment regulating force of the chiral agent.

When the composition for forming an optically anisotropic layer contains an alignment control agent, the content is preferably 0.01 to 10% by mass, and 0.05 to 5% by mass based on the total solid mass in the composition. More preferred. When the content is within this range, precipitation, phase separation, orientation defects, etc. can be suppressed while realizing a desired orientation state, and a uniform and highly transparent cured product can be obtained.

<Other ingredients>
The composition for forming an optically anisotropic layer may contain components other than those mentioned above. Other components include, for example, surfactants, tilt angle control agents, alignment aids, plasticizers, and crosslinking agents.

The optically anisotropic layer is a film formed using the composition for forming an optically anisotropic layer described above, and the manufacturing procedure thereof will be described later in the optically anisotropic layer of the method for manufacturing an optical film of the present invention. This will be explained in detail in the forming process.

The thickness of the optically anisotropic layer is not particularly limited, but from the viewpoint of making the device thinner, it is preferably 0.7 to 2.5 μm, more preferably 0.9 to 2.2 μm.

The alignment state of the polymerizable liquid crystal compound in the optically anisotropic layer may be any of homogeneous alignment (horizontal alignment), homeotropic alignment (vertical alignment), tilted alignment, and twisted alignment.
In particular, it is preferable that the optically anisotropic layer is a layer in which the homogeneous orientation or twisted orientation of the polymerizable liquid crystal compound is fixed because the orientation of the liquid crystal compound in the optically anisotropic layer is better. preferable.
Note that in this specification, "homogeneous alignment" means that the main surface of the optically anisotropic layer and the long axis direction of the polymerizable liquid crystal compound are parallel. Note that it is not required that they be strictly parallel, and in this specification, the orientation is such that the angle between the long axis direction of the polymerizable liquid crystal compound and the main surface of the optically anisotropic layer is less than 10°. shall mean.
In the optically anisotropic layer, the angle between the long axis direction of the polymerizable liquid crystal compound and the main surface of the optically anisotropic layer is preferably 0 to 5°, more preferably 0 to 3°, and preferably 0 to 2°. More preferred.

The optically anisotropic layer is more preferably a positive A plate or a positive C plate, and even more preferably a positive A plate.

Here, the positive A plate (positive A plate) and the positive C plate (positive C plate) are defined as follows.
The refractive index in the in-plane slow axis direction (direction where the in-plane refractive index is maximum) is nx, the refractive index in the direction orthogonal to the in-plane slow axis is ny, and the refraction in the thickness direction is When the ratio is nz, the positive A plate satisfies the relationship of formula (A1), and the positive C plate satisfies the relationship of formula (C1). Note that the positive A plate has a positive Rth value, and the positive C plate has a negative Rth value.
Formula (A1) nx>ny≒nz
Formula (C1) nz>nx≒ny
Note that the above "≒" includes not only the case where both are completely the same, but also the case where both are substantially the same.
Regarding this "substantially the same", for the positive A plate, for example, when (ny-nz) x d (where d is the thickness of the film) is -10 to 10 nm, preferably -5 to 5 nm. is also included in "ny≈nz", and a case where (nx-nz)×d is -10 to 10 nm, preferably -5 to 5 nm is also included in "nx≈nz". In addition, for positive C plates, for example, "nx≒ny" also includes cases where (nx - ny) x d (where d is the thickness of the film) is 0 to 10 nm, preferably 0 to 5 nm. .

When the optically anisotropic layer is a positive A plate, from the viewpoint of functioning as a λ/4 plate, Re(550) is preferably 100 to 180 nm, more preferably 120 to 160 nm, and 130 to 150 nm. More preferably, the wavelength is from 130 to 145 nm, particularly preferably from 130 to 145 nm.
Here, the "λ/4 plate" is a plate that has a λ/4 function, specifically, the function of converting linearly polarized light of a certain wavelength into circularly polarized light (or from circularly polarized light to linearly polarized light). It is a board with

[Method for manufacturing optical film]
The method for producing an optical film of the present invention includes a support production step of producing a support containing the above-mentioned specific surfactant, a rubbing step of subjecting the support to a rubbing treatment, and an optical film production method containing a polymerizable liquid crystal compound. This manufacturing method includes an optically anisotropic layer forming step of forming an optically anisotropic layer on a support that has been subjected to a rubbing treatment using a composition for forming an optically anisotropic layer.
Below, the procedure of each step will be explained in detail.

[Support production process]
The support preparation step is a step of preparing a support containing the above-mentioned specific surfactant.
Here, the support produced in this step is the one described as a support included in the optical film of the present invention.

The method for producing the support is not particularly limited, but includes, for example, a method including a step of casting a dope containing the above-mentioned specific surfactant.
In addition, as for the method of preparing and casting the dope, conventionally known methods can be suitably employed, except for incorporating the above-mentioned specific surfactant into the dope.

Other methods for producing the support include a method that includes a step of impregnating the surface of a polymer film with a composition containing the above-mentioned specific surfactant and solvent.
Here, examples of the solvent used together with the above-mentioned specific surfactant include the solvents described in the composition for forming an optically anisotropic layer. The solvent used can be appropriately selected depending on the properties of the base material used, such as the ease with which it penetrates.
Further, examples of the polymer film include those similar to those described in connection with the support included in the optical film of the present invention, and among them, it is preferable to use a cellulose acylate film.
Further, the method of impregnating the composition onto the polymer film is not particularly limited, and examples thereof include coating methods, and specifically, wire bar coating method, extrusion coating method, direct gravure coating method, reverse gravure coating method, and die coating method.

[Rubbing process]
The rubbing step is a step in which a support containing the above-mentioned specific surfactant is subjected to a rubbing treatment.
Here, for the rubbing treatment, a treatment method that is widely adopted as a liquid crystal alignment treatment process for liquid crystal display devices can be applied. That is, a method is used to obtain orientation by rubbing the surface of the orientation film in a certain direction using paper, gauze, felt, rubber, nylon, polyester fiber, or the like.

[Optically anisotropic layer formation process]
The optically anisotropic layer forming step is a step of forming an optically anisotropic layer on a rubbed support using an optically anisotropic layer forming composition.

One embodiment of the specific procedure for forming an optically anisotropic layer is to apply a composition for forming an optically anisotropic layer onto a support, form a coating film on the support, and apply the composition in the coating film. After aligning the polymerizable liquid crystal compound, the coating film may be subjected to a curing treatment to form an optically anisotropic layer.
Examples of methods for applying the composition for forming an optically anisotropic layer onto the support include wire bar coating method, extrusion coating method, direct gravure coating method, reverse gravure coating method, and die coating method. .
After applying the composition for forming an optically anisotropic layer onto the support, if necessary, the support coated with the composition for forming an optically anisotropic layer is subjected to a drying treatment to remove the solvent. May be implemented.

The method for orienting the polymerizable liquid crystal compound in the coating film (orientation treatment) is not particularly limited, and examples thereof include a method of heating the coating film and a method of drying the coating film at room temperature. In the case of a thermotropic liquid crystal compound, the liquid crystal phase formed by the alignment treatment can generally be transformed by a change in temperature. In the case of a lyotropic liquid crystal compound, the transition can also be caused by changing the composition ratio such as the amount of solvent.
Note that the conditions for heating the coating film are not particularly limited, but the heating temperature is preferably 50 to 150°C, and the heating time is preferably 10 seconds to 5 minutes.

Next, the coating film in which the polymerizable liquid crystal compound is oriented is subjected to a curing treatment to form an optically anisotropic layer.
The method of curing treatment is not particularly limited, and includes light irradiation treatment and heat treatment, with light irradiation being more preferred.
The type of light used during exposure is not particularly limited, but ultraviolet light is preferred.
The irradiation amount during exposure is not particularly limited, and is preferably 10 mJ/cm ² to 50 J/cm ² , more preferably 20 mJ/cm ² to 5 J/cm ² . Moreover, in order to promote the polymerization reaction, it may be carried out under heating conditions.

[Polarizer]
The polarizing plate of the present invention is a polarizing plate having the optical film of the present invention and a polarizer.

[Polarizer]
The polarizer included in the polarizing plate of the present invention is not particularly limited as long as it is a member that has the function of converting light into specific linearly polarized light, and conventionally known absorption type polarizers and reflection type polarizers can be used. .
As the absorption type polarizer, an iodine polarizer, a dye polarizer using a dichroic dye, a polyene polarizer, etc. are used. Iodine-based polarizers and dye-based polarizers include coating-type polarizers and stretched-type polarizers, and both can be applied, but polarized light produced by adsorbing iodine or dichroic dye to polyvinyl alcohol and stretching it Child is preferred.
In addition, as a method for obtaining a polarizer by stretching and dyeing a laminated film in which a polyvinyl alcohol layer is formed on a base material, Japanese Patent No. 5048120, Japanese Patent No. 5143918, Japanese Patent No. 4691205, Publication No. 4751481 and Japanese Patent No. 4751486 are mentioned, and known techniques regarding these polarizers can also be preferably used.
As a coating type polarizer, WO2018/124198, WO2018/186503, WO2019/132020, WO2019/132018, WO2019/189345, JP 2019-197168, JP 2019-194685, and JP 2019-139 No. 222 Publications are listed, and known techniques related to these polarizers can also be preferably used.
As the reflective polarizer, a polarizer in which thin films with different birefringences are laminated, a wire grid polarizer, a polarizer in which a cholesteric liquid crystal having a selective reflection region and a quarter-wave plate are combined, etc. are used.
Among these, polyvinyl alcohol-based resins (polymer containing -CH ₂ -CHOH- as a repeating unit; in particular, at least one selected from the group consisting of polyvinyl alcohol and ethylene-vinyl alcohol copolymer) have better adhesion. 1) is preferred.
Further, from the viewpoint of imparting crack resistance, the polarizer may have depolarization portions formed along opposing edges. Examples of the depolarization unit include Japanese Patent Application Laid-Open No. 2014-240970.
Further, the polarizer may have non-polarizing portions arranged at predetermined intervals in the longitudinal direction and/or the width direction. The non-polarized portion is a partially bleached portion. The arrangement pattern of the non-polarizing portions can be appropriately set depending on the purpose. For example, when the polarizer is cut to a predetermined size (cutting, punching, etc.) in order to attach it to an image display device of a predetermined size, the non-polarizing portion is placed at a position corresponding to the camera portion of the image display device. Examples of the arrangement pattern of the non-polarizing portion include Japanese Patent Application Laid-open No. 2016-27392.

The thickness of the polarizer is not particularly limited, but is preferably 3 to 60 μm, more preferably 3 to 30 μm, and even more preferably 3 to 10 μm.

In addition to the optical film and polarizer of the invention, the polarizing plate of the invention may have other optical films, a protective film described below, and other functional layers. The function of the functional layer is not particularly limited, and for example, it may be a layer having functions such as an adhesive layer, a stress relaxation layer, a flattening layer, an antireflection layer, a refractive index adjustment layer, and an ultraviolet absorption layer.
The protective film may be used on both sides of the polarizer, or may be used only on one side of the polarizer.
In addition, when the protective film is on the same side as the optical film of the present invention, it can be placed between the polarizer and the optical film, or on the opposite side of the optical film from the polarizer, via an adhesive or an adhesive. You may.
The polarizing plate can be used as a circularly polarizing plate when the optically anisotropic layer of the optical film of the invention described above or the optically anisotropic layer of the invention is a λ/4 plate (positive A plate).
When using the polarizing plate as a circularly polarizing plate, the optically anisotropic layer described above is a λ/4 plate (positive A plate), and the angle between the slow axis of the λ/4 plate and the absorption axis of the polarizer described later is is preferably 30 to 60°, more preferably 40 to 50°, even more preferably 42 to 48°, and particularly preferably 45°.
Here, the "slow axis" of the λ/4 plate means the direction in which the refractive index is maximum within the plane of the λ/4 plate, and the "absorption axis" of the polarizer means the direction in which the absorbance is highest. do.
Further, the polarizing plate can also be used as an optical compensation film of an IPS (In-Plane-Switching) type or FFS (Fringe-Field-Switching) type liquid crystal display device.
When the polarizing plate is used as an optical compensation film for an IPS mode or FFS mode liquid crystal display device, the above-mentioned optically anisotropic layer is used as at least one plate of a laminate of a positive A plate and a positive C plate. It is preferable that the angle between the slow axis of the plate layer and the absorption axis of the polarizer be perpendicular or parallel. Specifically, the angle between the slow axis of the positive A plate layer and the absorption axis of the polarizer is preferably More preferably, the angle is 0-5° or 85-95°.
In addition, when the above optical compensation film has a polarizer, a positive C plate, and a positive A plate laminated in this order, the angle between the slow axis of the positive A plate and the absorption axis of the polarizer is parallel to each other. It is more preferable that
Similarly, when the optical compensation film has a polarizer, a positive A plate, and a positive C plate laminated in this order, the angle between the slow axis of the positive A plate and the absorption axis of the polarizer is More preferably, they are orthogonal.
When the polarizing plate of the present invention is used in a liquid crystal display device to be described later, it is preferable that the angle between the slow axis of the optically anisotropic layer and the absorption axis of the polarizer be parallel or orthogonal.
In addition, in this specification, "parallel" does not require strictly parallel, but means that the angle formed by one side and the other side is less than 10 degrees. Further, in this specification, "orthogonal" does not necessarily require that they be strictly orthogonal, but means that the angle between one and the other is more than 80° and less than 100°.

〔Protective film〕
The material for the protective film is not particularly limited, and includes, for example, the same polymer films as described in the support of the optical film of the present invention, and among them, it is preferable to use cellulose acylate film.

The optical properties of the protective film are not particularly limited, but when the protective film is on the same side as the optical film of the present invention, it is preferable that the following formula is satisfied.
0nm≦Re(550)≦10nm
-40nm≦Rth(550)≦40nm

[Adhesive layer]
In the polarizing plate, an adhesive layer may be disposed between the optical film of the present invention and the polarizer.
As for the material forming the adhesive layer, for example, the ratio of storage elastic modulus G' to loss elastic modulus G'' (tan δ=G''/G') measured with a dynamic viscoelasticity measuring device is 0.001 to 1. .5, including so-called adhesives and substances that tend to creep. Examples of the adhesive include, but are not limited to, polyvinyl alcohol adhesives.

[Adhesive layer]
In the polarizing plate, an adhesive layer may be disposed between the optical film of the present invention and the polarizer.
As the adhesive layer, a curable adhesive composition that is cured by irradiation with active energy rays or heating is preferable.
Examples of the curable adhesive composition include a curable adhesive composition containing a cationically polymerizable compound and a curable adhesive composition containing a radically polymerizable compound.
The thickness of the adhesive layer is preferably 0.01 to 20 μm, more preferably 0.01 to 10 μm, and even more preferably 0.05 to 5 μm. If the thickness of the adhesive layer is within this range, no lifting or peeling will occur between the protective layer or optically anisotropic layer to be laminated and the polarizer, and adhesive strength without any practical problems can be obtained. Further, from the viewpoint of suppressing the generation of bubbles, the thickness of the adhesive layer is preferably 0.4 μm or more.
Further, from the viewpoint of durability, the bulk water absorption rate of the adhesive layer may be adjusted to 10% by mass or less, preferably 2% by mass or less. The bulk water absorption rate is measured according to the water absorption rate test method described in JIS K 7209.
As for the adhesive layer, for example, paragraphs [0062] to [0080] of JP-A-2016-35579 can be referred to, and the contents thereof are incorporated into the present specification.

[Easy adhesive layer]
In the polarizing plate, an easily adhesive layer may be disposed between the optical film of the present invention and the polarizer.
In order to have excellent adhesion between the optical film of the present invention and the polarizer, and to prevent cracks from forming in the polarizer, the storage modulus of the easy-adhesive layer at 85°C is 1.0×10 ⁶ Pa or more. It is preferable that it is 1.0×10 ⁷ Pa. Examples of constituent materials of the easily adhesive layer include polyolefin components and polyvinyl alcohol components. The thickness of the adhesive layer is preferably 500 nm to 1 μm.
As for the easy-adhesive layer, for example, paragraphs [0048] to [0053] of JP-A-2018-36345 can be referred to, and the contents thereof are incorporated into the present specification.

[Image display device]
The image display device of the present invention is an image display device having the optical film of the present invention or the optically anisotropic layer of the present invention.
The display element used in the image display device is not particularly limited, and includes, for example, a liquid crystal cell, an organic electroluminescence (hereinafter abbreviated as "EL (Electro Luminescence)") display panel, a plasma display panel, and the like. Among these, liquid crystal cells and organic EL display panels are preferred, and liquid crystal cells are more preferred.
That is, as the image display device, a liquid crystal display device using a liquid crystal cell as a display element or an organic EL display device using an organic EL display panel as a display element is preferable, and a liquid crystal display device is more preferable.

[Liquid crystal display device]
A liquid crystal display device, which is an example of an image display device, includes the above-mentioned polarizing plate and a liquid crystal cell.
Note that among the polarizing plates provided on both sides of the liquid crystal cell, it is preferable to use the above-described polarizing plate as the front-side polarizing plate, and it is more preferable to use the above-mentioned polarizing plates as the front-side and rear-side polarizing plates.
The liquid crystal cell constituting the liquid crystal display device will be described in detail below.

<Liquid crystal cell>
The liquid crystal cells used in liquid crystal display devices are in VA (Vertical Alignment) mode, OCB (Optically Compensated Bend) mode, IPS (In-Plane-Switching) mode, FFS (Fringe-Field-Switching) mode, or TN (Twisted) mode. Nematic) mode is preferable, but is not limited thereto.
In a TN mode liquid crystal cell, rod-like liquid crystal molecules are substantially horizontally aligned when no voltage is applied, and are further twisted at an angle of 60 to 120°. TN mode liquid crystal cells are most commonly used as color TFT liquid crystal display devices, and are described in numerous documents.
In a VA mode liquid crystal cell, rod-like liquid crystal molecules are aligned substantially vertically when no voltage is applied. VA mode liquid crystal cells include (1) narrowly defined VA mode liquid crystal cells in which rod-shaped liquid crystal molecules are aligned substantially vertically when no voltage is applied, and substantially horizontally when voltage is applied (Japanese Patent Application Laid-Open No. 2002-2002); In addition to (2) a multi-domain (MVA mode) liquid crystal cell (SID97, described in Digest of tech.Papers (Proceedings) 28 (1997) 845) in which VA mode is multi-domained to expand the viewing angle (described in Publication No. 176625) ), (3) Liquid crystal cell in a mode (n-ASM mode) in which rod-shaped liquid crystal molecules are aligned substantially vertically when no voltage is applied, and twisted and multi-domain aligned when a voltage is applied (Proceedings of the Japan Liquid Crystal Conference 58-59) (1998)), and (4) SURVIVAL mode liquid crystal cell (presented at LCD International 98). Further, the VA mode liquid crystal cell may be any of the PVA (Patterned Vertical Alignment) type, the optical alignment type (Optical Alignment), and the PSA (Polymer-Sustained Alignment) type. Details of these modes are described in Japanese Patent Application Laid-open No. 2006-215326 and Japanese Patent Application Publication No. 2008-538819.
In an IPS mode liquid crystal cell, rod-shaped liquid crystal molecules are aligned substantially parallel to the substrate, and when an electric field parallel to the substrate surface is applied, the liquid crystal molecules respond in a planar manner. In the IPS mode, a black display occurs when no electric field is applied, and the absorption axes of the pair of upper and lower polarizing plates are perpendicular to each other. A method of using an optical compensatory sheet to reduce leakage light during black display in an oblique direction and improve the viewing angle is disclosed in JP-A-10-54982, JP-A-11-202323, and JP-A-9-292522. JP-A-11-133408, JP-A-11-305217, and JP-A-10-307291.

[Organic EL display device]
An organic EL display device, which is an example of an image display device, includes, for example, a polarizer, a λ/4 plate (positive A plate) made of the above-mentioned optically anisotropic layer, and an organic EL display panel from the viewing side. Examples include embodiments in which the elements are arranged in this order.
Furthermore, an organic EL display panel is a display panel constructed using an organic EL element in which an organic light emitting layer (organic electroluminescence layer) is sandwiched between electrodes (between a cathode and an anode). The structure of the organic EL display panel is not particularly limited, and a known structure may be employed.

The present invention will be described in more detail below based on Examples. The materials, usage amounts, proportions, processing details, processing procedures, etc. shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the Examples shown below.

[Example 1]
[Preparation of cellulose acylate film (support)]
A cellulose acylate dope having the following composition was put into a mixing tank, stirred, and further heated at 90° C. for 10 minutes.
Thereafter, the resulting composition was filtered through a filter paper with an average pore size of 34 μm and a sintered metal filter with an average pore size of 10 μm to prepare a dope.
The solid content concentration of the dope is 23.5% by mass, the amount of plasticizer added is the ratio to cellulose acylate, and the solvent of the dope is methylene chloride/methanol/butanol = 81/18/1 (mass ratio). .

――――――――――――――――――――――――――――――――
Cellulose acylate dope――――――――――――――――――――――――――――――――
Cellulose acylate (degree of acetyl substitution 2.86, viscosity average degree of polymerization 310)
100 parts by weight Sugar ester compound 1 (shown in chemical formula (S4)) 6.0 parts by weight Sugar ester compound 2 (shown in chemical formula (S5)) 2.0 parts by weight Silica particle dispersion (AEROSIL R972, Nippon Aerosil Co., Ltd.) made)
0.1 parts by mass Sodium dodecyl sulfate 0.75 parts by mass Solvent (methylene chloride/methanol/butanol)
――――――――――――――――――――――――――――――――

The dope prepared above was cast using a drum film forming machine.
Specifically, the dope was cast from a die so as to be in contact with a metal support cooled to 0° C., and then the obtained web (film) was peeled off. Note that the drum was made of SUS (Stainless Used Steel).
Next, the web (film) obtained by casting is peeled from the drum, and then heated at 30 to 40°C during film transport in a tenter equipment that clips both ends of the web with clips and transports it. Dry for a minute. Subsequently, the web was post-dried by zone heating while being rolled.
Next, the obtained web was subjected to knurling, and then a winding support S-1 was produced.

[Formation of optically anisotropic layer]
The wound support S-1 produced above was continuously subjected to a rubbing treatment. At this time, the longitudinal direction of the long film was parallel to the transport direction, and the angle between the film longitudinal direction (transport direction) and the rotation axis of the rubbing roller was 80°. If the longitudinal direction of the film (conveyance direction) is 90°, and the clockwise direction is expressed as a positive value with the film width direction as the reference (0°) when observed from the film side, the rotation axis of the rubbing roller is at 10°. . In other words, the position of the rotation axis of the rubbing roller is a position rotated 80 degrees counterclockwise with respect to the longitudinal direction of the film.

Using the rubbed cellulose acylate film as a support, a composition for forming an optically anisotropic layer (1) containing a rod-like liquid crystal compound having the following composition was applied using a Giesser coating machine to form a composition layer. Formed.
Next, the obtained composition layer was heated at 80° C. for 60 seconds. By this heating, the rod-like liquid crystal compound of the composition layer was oriented in a predetermined direction.
Thereafter, the composition layer was irradiated with ultraviolet rays (irradiation amount: 35 mJ/ ^cm2 ).
Subsequently, the obtained composition layer was heated at 80° C. for 10 seconds.
Thereafter, a nitrogen purge was performed, and the composition layer was irradiated with ultraviolet rays at 80°C with an oxygen concentration of 100 volume ppm using a metal halide lamp (manufactured by Eye Graphics Co., Ltd.) (irradiation amount: 500 mJ/cm). ² ) An optically anisotropic layer in which the alignment state of the liquid crystal compound was fixed was formed. In this way, an optical film (F-1) was produced.

――――――――――――――――――――――――――――――――
Composition for forming optically anisotropic layer (1)
――――――――――――――――――――――――――――――――
- 80 parts by mass of the following rod-like liquid crystal compound (A) - 17 parts by mass of the following rod-like liquid crystal compound (B) - 3 parts by mass of the following polymerizable compound (C) - Ethylene oxide-modified trimethylolpropane triacrylate (V#360, Osaka Organic Chemical) Co., Ltd.) 4 parts by mass Photopolymerization initiator (Irgacure 819, manufactured by BASF) 3 parts by mass 0.46 parts by mass of the following left-handed chiral agent (L2) 0.41 parts by mass of the following right-handed chiral agent (R2) 0.08 parts by mass of the following polymer (A) 0.38 parts by mass of the following polymer (B) 117 parts by mass of methyl isobutyl ketone 23 parts by mass of ethyl propionate 16 parts by mass of cyclohexane ――――――――――――――――――――――――

Rod-like liquid crystal compound (A) [a mixture of the following liquid crystal compounds (RA), (RB), and (RC) in a mass ratio of 84:14:2]

Rod-shaped liquid crystal compound (B)

Polymerizable compound (C)

Left-handed chiral agent (L2)

Right-handed chiral agent (R2)

Polymer (A) [Fluorine part: 39% by mass, Mesogen part: 61% by mass]

Polymer (B) [In the formula, the numerical value described in each repeating unit represents the content (mass%) of each repeating unit with respect to all repeating units. ]

The optical film (F-1) prepared above was cut parallel to the rubbing direction, and the optically anisotropic layer was observed from the cross-sectional direction with a polarizing microscope. The thickness of the optically anisotropic layer was 2.7 μm, and the region (second region) of the optically anisotropic layer with a thickness (d2) of 1.3 μm on the substrate side was homogeneous alignment without twist angle, and the region (first region) of the optically anisotropic layer with a thickness (d1) of 1.4 μm on the air side (opposite to the substrate) was twist alignment of the liquid crystal compound.
The optical properties of the optical film (F-1) were determined using Axoscan from Axometrics and its analysis software (Multi-Layer Analysis). The product (Δn2d2) of Δn2 and thickness d2 at a wavelength of 550 nm in the second region was 173 nm, the twist angle of the liquid crystal compound was 0°, and the alignment axis angle of the liquid crystal compound relative to the long length direction was −10° on the side in contact with the substrate and −10° on the side in contact with the first region.
In addition, the product (Δn1d1) of Δn1 and thickness d1 at a wavelength of 550 nm in the first region was 184 nm, the twist angle of the liquid crystal compound was 75°, and the alignment axis angle of the liquid crystal compound relative to the longitudinal direction was -10° on the side in contact with the second region and -85° on the air side.

[Examples 2 to 13 and Comparative Examples 1 to 3]
An optical film was produced in the same manner as in Example 1, except that the type and amount of the surfactant were changed as shown in Table 1 below. Note that Comparative Example 1 is an example in which no surfactant was blended, and is indicated as "-" in Table 1 below.
Furthermore, the structures of copolymer A, copolymer B, and copolymer C used as surfactants in Examples 11 to 13 are as follows.

Copolymer A

Copolymer B

Copolymer C

[Example 14]
Example 2 except that the composition for forming an optically anisotropic layer (1) was changed to the composition for forming an optically anisotropic layer (2) shown below, and the optically anisotropic layer was formed under the following conditions. An optical film was prepared in the same manner as above.

――――――――――――――――――――――――――――――――
Composition for forming optically anisotropic layer (2)
――――――――――――――――――――――――――――――――
- 80 parts by mass of the rod-like liquid crystal compound (A) - 17 parts by mass of the rod-like liquid crystal compound (B) - 3 parts by mass of the polymerizable compound (C) - Ethylene oxide-modified trimethylolpropane triacrylate (V#360, Osaka Organic Chemical) Co., Ltd.) 4 parts by mass Photopolymerization initiator (Irgacure 819, manufactured by BASF) 3 parts by mass - The above left-handed chiral agent (L2) 0.46 parts by mass - The above right-handed chiral agent (R2) 0.41 parts by mass parts・0.08 parts by mass of the above polymer (A)・156 parts by mass of o-xylene―――――――――――――――――――――――――――― ---

[Example 15]
No surfactant (sodium dodecyl sulfate) was added to the cellulose acylate dope, and before rubbing, the following surfactant-containing composition was applied with a #8 bar and then dried at 80°C for 1 minute. An optical film was produced in the same manner as in Example 1, except for the following steps.
――――――――――――――――――――――――――――――――
Surfactant-containing composition――――――――――――――――――――――――――――――
・Sodium dodecyl sulfate 0.5 parts by mass ・Isopropyl alcohol 90.0 parts by mass ・Water 10.0 parts by mass―――――――――――――――――――――――― ――――――――

[Example 16]
The composition for forming an optically anisotropic layer (1) was changed to the composition for forming an optically anisotropic layer (3) shown below, and the position of the rotation axis of the rubbing roller was changed from -10° to +12.5°. An optical film was produced in the same manner as in Example 2 except for the following.
The thickness of the optically anisotropic layer obtained was 1.0 μm. The average inclination angle of the long axis of the rod-like liquid crystal compound with respect to the film plane was 0°, and it was confirmed that the liquid crystal compound was oriented horizontally with respect to the film plane. In addition, the angle of the slow axis is perpendicular to the rotation axis of the rubbing roller, and the film width direction is 0° (film longitudinal direction is 90°, clockwise with respect to the film width direction when observed from the optically anisotropic layer C side). (The direction is expressed as a positive value.), it was -77.5°. The in-plane retardation of the optically anisotropic layer at a wavelength of 550 nm is 116 nm, and the optically anisotropic layer exhibits normal wavelength dispersion.

――――――――――――――――――――――――――――――――
Composition for forming optically anisotropic layer (3)
――――――――――――――――――――――――――――――――
- 100 parts by mass of the above rod-shaped liquid crystal compound (A) - 6 parts by mass of photopolymerization initiator (Irgacure 907, manufactured by BASF) - 0.25 parts by mass of the following fluorine-containing compound (F-1) - 0.25 parts by mass of the following fluorine-containing compound (F-1) 2) 0.1 parts by mass 4 parts by mass of ethylene oxide-modified trimethylol propane triacrylate 337 parts by mass of methyl isobutyl ketone―――――――――――――――――――――― ――――――――――

Fluorine-containing compound (F-1)

Fluorine-containing compound (F-2)

[Comparative example 4]
An optical film was produced in the same manner as in Example 1, except that instead of the winding support S-1, A4160 (one-sided easily adhesive type, thickness 50 μm), a support manufactured by Toyobo Co., Ltd., was used. did.

[Comparative example 5]
A (meth)acrylic resin film having a lactone ring structure and having an easily adhesive layer on one side and having a thickness of 58 μm was prepared in the same manner as in Example 4 of JP-A-2012-93703.
An optical film was produced in the same manner as in Example 1, except that the (meth)acrylic resin film produced above was used in place of the winding support S-1.

[evaluation]
The produced optical film was evaluated as follows. The results are shown in Table 1 below.
In addition, when the produced optical film was analyzed for components in the depth direction using a time-of-flight secondary ion mass spectrometer (TOF-SIMS) (“SIMS5” manufactured by IONTOF), Examples 1 to 16, Regarding the optical films prepared in Comparative Examples 2, 3, and 5, it was confirmed that the surfactant was present in the region from the optically anisotropic layer side surface of the support to 10% of the thickness of the support, and Comparative Example 1 Regarding the optical films prepared in 4 and 4, it was confirmed that the support did not contain a surfactant.
Furthermore, from the above component analysis, it was confirmed that the optical anisotropic layer and the support were adjacent to each other in the optical films produced in Examples 1 to 16 and Comparative Examples 1 to 3, and It was confirmed that the optical film produced in the above had an easily adhesive layer between the optically anisotropic layer and the support.

[Dynamic friction coefficient]
The load applied when the SUS ball was rolled while applying a 100 g load to the surface of the support was measured, and the coefficient of dynamic friction was measured.

[Orientation]
The optically anisotropic layer in the obtained optical film was randomly observed under a polarizing microscope in a crossed nicol state at a magnification of 50 times (field size: 1715 x 1280 μm), and each field was classified into the following three categories.
I: No optical defects observed.
II: Slight optical defects are observed, but at a level that causes no practical problems.
III: Many optical defects were observed, which was at a level that would pose a practical problem.
The 10 visual fields were evaluated in the following five stages.
A: All 10 fields are I or II, and the number of II fields is 0 to 2 fields.
B: All 10 fields are I or II, and the number of II fields is 3 to 5.
C: All 10 visual fields are I or II, and the number of II visual fields is 6 to 10.
D: 10 visual fields include III, and the number of III visual fields is 1 to 5.
E: 10 visual fields include III, and the number of III visual fields is 6 to 10.

[Bright spot defect]
Two polarizing plates were placed on top of the Scherkasten in a crossed nicol state, and the obtained optical film (observation area: 1×1 m) was sandwiched between the two polarizing plates to allow light to pass through the Scherkasten. The optical film was observed from above the polarizing plate using a magnifying glass, and defects with a diameter of 100 μm or more were marked. A cross-section was cut using a microtome so as to pass through the center of the marked defect, and optical microscopic observation was performed from the cross-sectional direction. Defects in which foreign matter was observed in the optically anisotropic layer were counted and evaluated according to the following criteria. The optical films produced in Comparative Examples 4 and 5 had poor orientation and bright spot defects could not be evaluated accurately, so they were not evaluated and were indicated as "-" in Table 1 below.
A: 2 or less defects B: 3 to 4 defects C: 5 to 8 defects D: 8 to 20 defects E: 21 or more defects

From the results shown in Table 1, the orientation of the liquid crystal compound in the optically anisotropic layer is good when no specific surfactant is blended into the support or when a surfactant that does not fall under the specific surfactant is blended. However, it was found that the occurrence of bright spot defects could not be suppressed (Comparative Examples 1 to 3).
Furthermore, it was found that in embodiments where the support and the optically anisotropic layer were not adjacent to each other, the orientation of the liquid crystal compound in the optically anisotropic layer was poor (Comparative Examples 4 and 5).
On the other hand, if the support adjacent to the optically anisotropic layer contains a specific surfactant, the orientation of the liquid crystal compound in the optically anisotropic layer will be good, and bright spot defects will occur. It was also found that this can be suppressed (Examples 1 to 16).
In particular, from the comparison between Examples 1 to 4 and 7 and Examples 5 to 6, when the specific surfactant has an ionic hydrophilic group (Examples 1 to 4 and 7), optical It was found that the orientation of the liquid crystal compound in the anisotropic layer was improved, and the occurrence of bright spot defects in the optical film could be further suppressed.
In addition, from the comparison between Example 1 and Example 10 and the comparison between Example 2 and Example 7, it was found that when the specific surfactant has an anionic hydrophilic group, the optically anisotropic layer It was found that the alignment of the liquid crystal compound was further improved, and the occurrence of bright spot defects in the optical film could be further suppressed.
Furthermore, from a comparison between Examples 1 to 3 and Example 11, when the specific surfactant is a polymer compound, the orientation of the liquid crystal compound in the optically anisotropic layer is better, and the brightness in the optical film is improved. It was found that the occurrence of point defects could be further suppressed.
Further, from comparison with Examples 1 to 7, it was found that when the hydrophobic group of the specific surfactant is an alkyl group having 12 to 18 carbon atoms, the occurrence of bright spot defects in the optical film can be further suppressed.

Claims

An optical film having a support and an optically anisotropic layer adjacent to each other,
The optically anisotropic layer is a layer formed using an optically anisotropic layer forming composition containing a polymerizable liquid crystal compound,
The support contains a surfactant having a hydrophilic group and a hydrophobic group,
The optical film, wherein the hydrophobic group is at least one group selected from the group consisting of an alkyl group having 5 to 29 carbon atoms, a silicon-containing group, and a fluorine-containing group.
The optically anisotropic layer is a layer in which the alignment state of the polymerizable liquid crystal compound is fixed,
The optical film according to claim 1, wherein the orientation state is a homogeneous orientation or a twisted orientation.
The optical film according to claim 1, wherein the support is a cellulose acylate film.
The optical film according to claim 1, wherein the hydrophilic group of the surfactant is an ionic hydrophilic group.
The optical film according to claim 1, wherein the hydrophilic group of the surfactant is an anionic hydrophilic group.
The optical film according to claim 1, wherein the surfactant is a polymer compound.
The optical film according to claim 1, wherein the hydrophobic group of the surfactant is an alkyl group having 12 to 18 carbon atoms.
A support production step of producing the support according to claim 1;
a rubbing step of applying a rubbing treatment to the support;
an optically anisotropic layer forming step of forming an optically anisotropic layer on the rubbed support using an optically anisotropic layer forming composition containing a polymerizable liquid crystal compound;
A method for producing an optical film, comprising:
The method for producing an optical film according to claim 8, wherein the support production step includes a step of casting a dope containing the surfactant according to claim 1.
The method for producing an optical film according to claim 8, wherein the support preparation step includes a step of impregnating the surface of the polymer film with a composition containing the surfactant and solvent according to claim 1.
A polarizing plate comprising the optical film according to any one of claims 1 to 7 and a polarizer.
An image display device comprising the optical film according to any one of claims 1 to 7.
The image display device according to claim 12, which is a liquid crystal display device.
The image display device according to claim 12, which is an organic electroluminescence display device.