CN111727392A

CN111727392A - Optical film, polarizing plate, and image display device

Info

Publication number: CN111727392A
Application number: CN201980013401.1A
Authority: CN
Inventors: 吉成伸一; 野尻真裕美; 野副宽; 饭泉隆史; 加藤考浩
Original assignee: Fujifilm Corp
Current assignee: Fujifilm Corp
Priority date: 2018-02-14
Filing date: 2019-02-13
Publication date: 2020-09-29
Anticipated expiration: 2039-02-13
Also published as: KR20200106068A; KR102413463B1; WO2019159960A1; CN111727392B; JP6916949B2; JPWO2019159960A1

Abstract

The invention provides an optical film comprising an optically anisotropic film which is excellent in reverse wavelength dispersibility and wet heat durability and in which alignment defects are suppressed. Another object of the present invention is to provide a polarizing plate using the optical film, and an image display device using the optical film or the polarizing plate. The optical film of the present invention comprises an optically anisotropic film, a photo-alignment film and a polymer support, which are formed from a polymerizable liquid crystal composition, in this order, wherein the polymerizable liquid crystal composition comprises a polymerizable liquid crystal compound having a predetermined structure, the load of the CLOGP value of each liquid crystal compound contained in the polymerizable liquid crystal composition is 10.0 to 20.0 on average, the photo-alignment film is formed from a composition for forming a thermally crosslinkable photo-alignment film, the composition for forming a photo-alignment film comprises a photo-alignment copolymer comprising a photo-alignment repeating unit having a predetermined structure and a thermally crosslinkable repeating unit having a predetermined structure, and the photo-alignment copolymer has a thermally crosslinkable group alignment equivalent of 340 to 500.

Description

Optical film, polarizing plate, and image display device

Technical Field

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

Background

Polymerizable compounds exhibiting reverse wavelength dispersibility have characteristics such as being capable of converting the wavelength of light accurately over a wide wavelength range and being capable of making a retardation film thin due to having a high refractive index, and therefore, studies have been actively made (for example, refer to patent documents 1 to 4).

In order to improve the productivity of the film and suppress foreign matter defects, a retardation film using a photo-alignment film is replaced with a retardation film using a conventional rubbing alignment film (see, for example, patent documents 5 to 7).

Prior art documents

Patent document

Patent document 1: japanese laid-open patent publication No. 2008-273925

Patent document 2: japanese patent laid-open No. 2010-031223

Patent document 3: international publication No. 2014/010325

Patent document 4: japanese patent laid-open publication No. 2016 081035

Patent document 5: japanese laid-open patent publication No. 8-015681

Patent document 6: japanese patent laid-open publication No. 2010-052273

Patent document 7: japanese laid-open patent publication No. 2010-096892

Disclosure of Invention

Technical problem to be solved by the invention

In recent years, as various display devices have been widely used in various applications, applications to use methods that have not been assumed in the past, such as use of a retardation film (optically anisotropic film) in a more severe moist heat environment or use of a foldable sheet-like ultra-thin display device, have been demanded.

The present inventors have studied the polymerizable liquid crystal compounds described in patent documents 1 to 3, which exhibit reverse wavelength dispersibility, and have found that the moisture-heat durability of the formed optically anisotropic film can be improved by selecting a polymerizable liquid crystal compound group (hereinafter, also referred to as "hydrophobic polymerizable liquid crystal compound") having a ClogP value as an index. However, it was found that: if the support is replaced with a polymer support in order to enable production by a roll-to-roll process, alignment defects of the optically anisotropic film increase compared to the case where the optically anisotropic film is tentatively provided on the photo-alignment film disposed on the glass plate as the support.

Accordingly, an object of the present invention is to provide an optical film including an optically anisotropic film which is excellent in reverse wavelength dispersibility and wet heat durability and in which alignment defects are suppressed.

Another object of the present invention is to provide a polarizing plate using the optical film, and an image display device using the optical film or the polarizing plate.

Means for solving the technical problem

As a result of intensive studies to solve the above problems, the present inventors have found that: even when an optically anisotropic film is formed on a polymer support using a polymerizable liquid crystal composition containing a hydrophobic polymerizable liquid crystal compound, the alignment of the optically anisotropic film can be uniformly and precisely controlled by using a specific photo-alignment copolymer in the composition for forming a photo-alignment film (an optically anisotropic film in which alignment defects are suppressed can be formed), and the present invention has been completed.

That is, the following configuration was found to solve the above problems.

[1]

An optical film comprising an optically anisotropic film formed from a polymerizable liquid crystal composition, a photo-alignment film and a polymer support in this order,

the polymerizable liquid crystal composition comprises a polymerizable liquid crystal compound represented by the following formula (1),

the load of the CLOGP value of each of the liquid crystal compounds contained in the polymerizable liquid crystal composition is 10.0 to 20.0 on average,

the photo-alignment film is formed from a thermally crosslinkable composition for forming a photo-alignment film,

the composition for forming a photo-alignment film comprises a photo-alignment copolymer containing a photo-alignment repeating unit represented by formula (A) described below and a thermal-crosslinkable repeating unit represented by formula (B) described below, and the photo-alignment copolymer has a thermal-crosslinkable group equivalent in the range of 340 to 500.

[2]

According to [1]The optical film, wherein m in the formula (1) is 1, A¹And G¹All of which are optionally substituted cyclohexylene, E¹Is a single bond, and,

n in the above formula (1) is 1, A²And G²All of which are optionally substituted cyclohexylene, E²Is a single bond.

[3]

According to [1]Or [ 2]]The optical film, wherein Ar in the above formula (1)¹Represents a group represented by the above formula (Ar-1) or (Ar-2).

[4]

The optical film according to any one of [1] to [3], wherein the thermally crosslinkable group contained in the photo-alignment copolymer is chain polymerizable,

the composition for forming a photo-alignment film includes the photo-alignment copolymer and a thermal polymerization initiator for initiating chain polymerization of the thermal crosslinkable group.

[5]

The optical film according to any one of [1] to [4], wherein the optically anisotropic film is provided on the photo-alignment film in a peelable manner, or the photo-alignment film is provided on the polymer support in a peelable manner.

[6]

A polarizing plate having the optical film of any one of [1] to [5] and a polarizer.

[7]

An image display device having the optical film of any one of [1] to [5] or the polarizing plate of [6 ].

Effects of the invention

According to the present invention, an optical film including an optically anisotropic film which is excellent in reverse wavelength dispersibility and wet heat durability and in which alignment defects are suppressed can be provided.

Further, the present invention can provide a polarizing plate using the optical film and an image display device using the optical film or the polarizing plate.

Drawings

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

Fig. 2 is a schematic cross-sectional view showing an example of a circularly polarizing plate including an optically anisotropic film transferred from the optical film of the present invention.

Fig. 3 is a schematic view showing an example of the process for producing the optical film of the present invention.

Detailed Description

The present invention will be described in detail below.

The following description of the constituent elements may be based on a representative embodiment of the present invention, but the present invention is not limited to such an embodiment.

In the present specification, the numerical range expressed by the term "to" refers to a range including numerical values before and after the term "to" as a lower limit value and an upper limit value.

In the present specification, the expression "(meth) acrylic acid" means "either or both of acrylic acid and methacrylic acid". The expression "(meth) acryloyl group" means "either or both of an acryloyl group and a methacryloyl group".

In the present specification, the bonding direction of the labeled 2-valent group (e.g., -CO-O-) is not particularly limited, and is, for example, D in the following formula (1)¹In the case of-CO-O-, if it is bonded to G¹The position of the side is set to 1, and the side is bonded to Ar¹The position of the side is set to 2, then D¹May be 1-CO-O-2 or 1-O-CO-2.

[ optical film ]

The optical film of the present invention comprises an optically anisotropic film formed from a polymerizable liquid crystal composition, a photo-alignment film, and a polymer support in this order.

Fig. 1 is a schematic cross-sectional view showing an example of the optical film of the present invention. Fig. 1 is a schematic view, and the relationship of the thicknesses, positional relationship, and the like of the respective layers do not necessarily coincide with the actual situation.

The optical film 10 shown in fig. 1 includes a polymer support 16, an alignment film 14, and an optically anisotropic film 12 in this order.

In the film that can be industrially used for the polymer support described later, various low-molecular functional additives may be contained in the film in order to control the physical properties of the film. In general, these additive components are hydrophobic in order to impart stable performance even under hot and humid conditions. Further, due to mixing in the production of raw materials or a processing environment in processing a thin film (for example, processing a polymer thin film, processing a surface modification layer, or the like), a polymer itself constituting the polymer support or a component constituting a surface modification layer (for example, an easy adhesion layer or the like) provided for modification of surface properties of the polymer support may contain a low molecular weight oligomer component and/or a hydrophobic low molecular weight impurity.

In the present specification, these low-molecular functional additives and the low-molecular weight oligomer component and the hydrophobic low-molecular weight impurity that are introduced into the polymer support due to mixing in during production of raw materials or a processing environment during processing of a thin film are collectively referred to as a hydrophobic low-molecular weight component derived from the polymer support.

Typically, the hydrophobic low-molecular component has a molecular weight of 3000 or less, preferably 300 to 3000, preferably 700 to 2000.

The inventors of the present invention have studied a glass plate and various polymer films as a support when forming an optically anisotropic film using a polymerizable liquid crystal composition containing the above polymerizable liquid crystal compound having reverse wavelength dispersibility and excellent wet heat durability, and as a result, have found that: although the polymerizable liquid crystal compound can achieve a good alignment state by a conventionally known photo-alignment film disposed on a glass plate, many alignment defects occur in various polymer films. The present inventors have found that, as a result of studying the cause of the alignment defect, a hydrophobic low-molecular-weight component derived from a polymer support is transferred to the optically anisotropic film to disturb the alignment of the polymerizable liquid crystal compound.

As a result of intensive studies by the inventors based on the above assumptions, they found that: when a specific photo-alignment film is used, an optical film including an optically anisotropic film exhibiting a good alignment state even in the case of using various polymer thin films can be obtained. That is, it was found that an optical film including an optically anisotropic film which is excellent in reverse wavelength dispersibility and wet heat durability and in which alignment defects are suppressed can be obtained.

Hereinafter, various members used in the optical film of the present invention will be described in detail.

[ optically anisotropic film ]

The optically anisotropic film constituting the present invention is an optically anisotropic film formed from a polymerizable liquid crystal composition described later. Examples of the method for forming the optically anisotropic film include a method in which a polymerizable liquid crystal composition described later is used to set a desired alignment state, and then the alignment state is fixed by polymerization.

The above optically anisotropic film shows reverse wavelength dispersibility.

The thickness of the optically anisotropic film is not particularly limited, but is preferably 0.1 to 10 μm, more preferably 0.5 to 5 μm, from the viewpoint that a thin film is desired when the film is mounted on a display device.

(polymerizable liquid Crystal composition)

The polymerizable liquid crystal composition used for forming the optically anisotropic film is a polymerizable liquid crystal composition containing a specific polymerizable liquid crystal compound described later, and the load of the ClogP value of each liquid crystal compound contained in the polymerizable liquid crystal composition is 10.0 to 20.0 on average. Here, the target liquid crystal compound is not limited to a specific polymerizable liquid crystal compound, and is all liquid crystal compounds contained in the polymerizable liquid crystal composition.

The ClogP value of a compound is a value obtained by calculating the common logarithm logP of the distribution coefficient P to 1-octanol and water. As the method and software for calculating the ClogP value, known methods and software can be used, but the ClogP program written in chembidraw Ultra 13.0 of Cambridge soft corporation is used in the present invention unless otherwise specified. In the present invention, the ClogP value is obtained by discarding 2 bits after the decimal point.

The load average is the sum of the products of the ClogP value of each compound and the proportion (mass proportion) of each compound in the total amount of solid components of the liquid crystal compound. In addition, when the number of the liquid crystal compounds is only 1, the ClogP value of the compound is treated as the load average value.

High ClogP means high affinity to a hydrophobic molecule (1-octanol as an index) compared to a water molecule. Therefore, although details are not clear, it is presumed that, by setting the load average of the ClogP value of the liquid crystal compound within the above range, the effect of water molecules and other polar components, which are factors of deterioration of the moist heat durability, on the liquid crystal molecular structure in the optically anisotropic film is suppressed, and as a result, the moist heat durability is improved.

Specific polymerizable liquid Crystal Compound

The polymerizable liquid crystal composition contains a polymerizable liquid crystal compound represented by the following formula (1) (hereinafter, also referred to as "specific polymerizable liquid crystal compound"). When a specific polymerizable liquid crystal compound is cured to form an optically anisotropic film, the optically anisotropic film exhibits reverse wavelength dispersibility.

Formula (1):

L¹-SP¹-(E³-A¹)_m-E¹-G¹-D¹-Ar¹-D²-G²-E²-(A²-E⁴)_n-SP²-L²

in the above formula (1), D¹、D²、E¹、E²、E³And E⁴Each independently represents a single bond, -CO-O-, -C (═ S) O-, -CR¹R²-、-CR¹R²-CR³R⁴-、-O-CR¹R²-、-CR¹R²-O-CR³R⁴-、-CO-O-CR¹R²-、-O-CO-CR¹R²-、-CR¹R²-O-CO-CR³R⁴-、-CR¹R²-CO-O-CR³R⁴-、-NR¹-CR²R³-or-CO-NR¹-。R¹、R²、R³And R⁴Each independently represents a hydrogen atom, a fluorine atom or an alkyl group having 1 to 4 carbon atoms.

In the above formula (1), G¹And G²Respectively independently represent a toolA substituted alicyclic hydrocarbon group having 2 valence of 5 to 8 carbon atoms, 1 or more-CH constituting the alicyclic hydrocarbon group₂-may be substituted by-O-, -S-or-NH-.

In the above formula (1), A¹And A²Each independently represents a 2-valent aromatic hydrocarbon group having 6 to 12 carbon atoms which may have a substituent or a 2-valent alicyclic hydrocarbon group having 5 to 8 carbon atoms which may have a substituent, and 1 or more-CH constituting the alicyclic hydrocarbon group₂-may be substituted by-O-, -S-or-NH-.

In the above formula (1), SP¹And SP²Each independently represents a single bond, a linear or branched alkylene group having 1 to 12 carbon atoms, or at least 1-CH constituting a linear or branched alkylene group having 1 to 12 carbon atoms₂A linking group having a valence of 2, which is substituted by-O-, -S-, -NH-, -N (Q) -or-CO-, wherein Q represents a substituent.

In the above formula (1), L¹And L²Each independently represents an organic group having a valence of 1, L¹And L²At least one of (a) and (b) represents a polymerizable group. Wherein, in Ar¹In the case of an aromatic ring represented by the following formula (Ar-3), L¹And L²And L in the following formula (Ar-3)³And L⁴At least one of (a) and (b) represents a polymerizable group.

In the formula (1), m represents an integer of 0 to 2, and when m is 2, a plurality of E³A may be the same or different, and a plurality of A¹May be the same or different.

In the formula (1), n represents an integer of 0 to 2, and when n is 2, a plurality of E⁴A may be the same or different, and a plurality of A²May be the same or different.

In the above formula (1), Ar¹Represents any aromatic ring selected from the group consisting of groups represented by the formulae (Ar-1) to (Ar-5) described later.

As the above-mentioned R¹、R²、R³And R⁴An alkyl group having 1 to 4 carbon atomsThe alkyl group may be linear, branched or cyclic, and specific examples thereof include methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl and tert-butyl.

In the above formula (1), as G¹And G²The alicyclic hydrocarbon group having a valence of 2 and having 5 to 8 carbon atoms is preferably a 5-or 6-membered ring. The alicyclic hydrocarbon group may be saturated or unsaturated, but is preferably saturated. As a group G¹And G²The alicyclic hydrocarbon group having a valence of 2 can be referred to, for example, in Japanese patent laid-open publication No. 2012-021068 [0078]]The paragraph is written in this specification.

Among them, cyclohexylene (a group having a valence of 2 derived from a cyclohexane ring) is preferable, 1, 4-cyclohexylene is more preferable, and trans-1, 4-cyclohexylene is further preferable.

In the above formula (1), G is¹And G²The substituent which the alicyclic hydrocarbon group having 2 valences and 5 to 8 carbon atoms may have is the same as Y in the formula (Ar-1) described later¹The aromatic hydrocarbon group having 6 to 12 carbon atoms and the aromatic heterocyclic group having 3 to 12 carbon atoms may have the same substituent.

In the above formula (1), A is¹And A²The C6-12 2-valent aromatic hydrocarbon group includes 1, 2-phenylene, 1, 3-phenylene, 1, 4-naphthylene, 1, 5-naphthylene and 2, 6-naphthylene, among which 1, 4-phenylene is preferred, trans-1, 4-phenylene is more preferred.

And as A¹And A²Examples of the alicyclic hydrocarbon group having 2 valences and 5 to 8 carbon atoms include G in the above formula (1)¹And G²The same groups as those described in (1) above are preferably cyclohexylene (a 2-valent group derived from a cyclohexane ring), more preferably 1, 4-cyclohexylene, and still more preferably trans-1, 4-cyclohexylene.

In the above formula (1), A is¹And A²The C6-12 aromatic hydrocarbon group with 2 valence and C5 ℃ &Examples of the substituent which may be contained in the 2-valent alicyclic hydrocarbon group of 8 include Y in the formula (Ar-1) described later¹The aromatic hydrocarbon group having 6 to 12 carbon atoms and the aromatic heterocyclic group having 3 to 12 carbon atoms may have the same substituent.

In the above formula (1), as SP¹And SP²Examples of the linear or branched alkylene group having 1 to 12 carbon atoms include a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, a methylhexenyl group, and a heptenyl group. In addition, as described above, SP¹And SP²May be at least 1-CH constituting a linear or branched alkylene group having 1 to 12 carbon atoms₂A linking group having a valence of 2 which is substituted by-O-, -S-, -NH-, -N (Q) -or-CO-, and the substituent represented by Q is the same as Y in the formula (Ar-1) described later¹The aromatic hydrocarbon group having 6 to 12 carbon atoms and the aromatic heterocyclic group having 3 to 12 carbon atoms may have the same substituent.

In the above formula (1), L represents¹And L²Examples of the 1-valent organic group include an alkyl group, an aryl group, a heteroaryl group, and a cyano group.

The alkyl group may be linear, branched or cyclic, but is preferably linear. The number of carbon atoms of the alkyl group is preferably 1 to 30, more preferably 1 to 20, and still more preferably 1 to 10.

Also, the aryl group may be monocyclic or polycyclic, but monocyclic is preferable. The number of carbon atoms of the aryl group is preferably 6 to 25, more preferably 6 to 10.

Also, the heteroaryl group may be monocyclic or polycyclic. The number of hetero atoms constituting the heteroaryl group is preferably 1 to 3. The hetero atom constituting the heteroaryl group is preferably a nitrogen atom, a sulfur atom or an oxygen atom. The number of carbon atoms of the heteroaryl group is preferably 6 to 18, more preferably 6 to 12. The alkyl group, the aryl group and the heteroaryl group may be unsubstituted or may have a substituent. Examples of the substituent include Y in the formula (Ar-1) described later¹The aromatic hydrocarbon group having 6 to 12 carbon atoms and the aromatic heterocyclic group having 3 to 12 carbon atoms may have the same substituent.

In the above formula (1), L¹And L²At least one polymerizable group represented by (a) is not particularly limited, but a polymerizable group capable of radical polymerization (radical polymerizable group) or a polymerizable group capable of cationic polymerization (cationic polymerizable group) is preferable.

As the radical polymerizable group, a known radical polymerizable group can be used, and an acryloyl group or a methacryloyl group is preferable. It is known that when comparing an acryloyl group and a methacryloyl group, the polymerization rate of the acryloyl group is generally high, and from the viewpoint of improving productivity, the acryloyl group is preferable, but the methacryloyl group can be similarly used as a polymerizable group.

As the cationically polymerizable group, a publicly known cationically polymerizable group can be used, and specific examples thereof include an alicyclic ether group, a cyclic acetal group, a cyclic lactone group, a cyclic thioether group, a spiroorthoester group, and an ethyleneoxy group. Among them, an alicyclic ether group or an ethyleneoxy group is preferable, and an epoxy group, an oxetanyl group or an ethyleneoxy group is more preferable.

Among the polymerizable groups, the following groups are preferable.

[ chemical formula 1]

In the formula (1), L in the formula (1) is L because the moist heat durability is further improved¹And L²All of them are preferably polymerizable groups, and more preferably acryloyl groups or methacryloyl groups.

On the other hand, in the above formula (1), Ar¹Represents any aromatic ring selected from the group consisting of groups represented by the following formulae (Ar-1) to (Ar-5). In the following formulae (Ar-1) to (Ar-5), D is the same as in the formula (I)¹Or D²The bonding position of (2).

The following describes formulae (Ar-1) to (Ar-5).

[ chemical formula 2]

In the above formula (Ar-1), Q¹Represents N or CH.

And, Q²represents-S-, -O-or-N (R)⁵)-，R⁵Represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

And, Y¹Represents an optionally substituted aromatic hydrocarbon group having 6 to 12 carbon atoms or an optionally substituted aromatic heterocyclic group having 3 to 12 carbon atoms.

Specific examples of the alkyl group having 1 to 6 carbon atoms represented by R5 include methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, and n-hexyl groups.

As Y¹The aromatic hydrocarbon group having 6 to 12 carbon atoms includes, for example, an aryl group such as a phenyl group, a 2, 6-diethylphenyl group, or a naphthyl group.

As Y¹Examples of the aromatic heterocyclic group having 3 to 12 carbon atoms include heteroaryl groups such as thienyl, thiazolyl, furyl and pyridyl.

And as Y¹The aromatic hydrocarbon group having 6 to 12 carbon atoms and the aromatic heterocyclic group having 3 to 12 carbon atoms may have a substituent, and examples thereof include an alkyl group, an alkoxy group, a halogen atom, and the like.

The alkyl group is preferably a linear, branched or cyclic alkyl group having 1 to 18 carbon atoms, more preferably an alkyl group having 1 to 8 carbon atoms (for example, methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, cyclohexyl, etc.), further preferably an alkyl group having 1 to 4 carbon atoms, and particularly preferably a methyl group or an ethyl group.

The alkoxy group is preferably an alkoxy group having 1 to 18 carbon atoms, more preferably an alkoxy group having 1 to 8 carbon atoms (e.g., methoxy group, ethoxy group, n-butoxy group, methoxyethoxy group, etc.), further preferably an alkoxy group having 1 to 4 carbon atoms, and particularly preferably a methoxy group or an ethoxy group.

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like, and among them, a fluorine atom or a chlorine atom is preferable.

And, in the above formulae (Ar-1) to (Ar-5), Z¹、Z²And Z³Independently represent a hydrogen atom, a 1-valent straight chain OR branched aliphatic hydrocarbon group having 1 to 20 carbon atoms, a 1-valent alicyclic hydrocarbon group having 3 to 20 carbon atoms, a 1-valent aromatic hydrocarbon group having 6 to 20 carbon atoms, a halogen atom, a cyano group, a nitro group, -OR⁶、-NR⁷R⁸、-SR⁹、-COOR^Xor-OCOR^Y，R⁶～R⁹、R^XAnd R^YEach independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, Z¹And Z²May be bonded to each other to form an aromatic ring.

The 1-valent linear or branched aliphatic hydrocarbon group having 1 to 20 carbon atoms is preferably an alkyl group having 1 to 15 carbon atoms, more preferably an alkyl group having 1 to 8 carbon atoms, and specifically more preferably a methyl group (Me), an ethyl group, an isopropyl group, a tert-amyl group (1, 1-dimethylpropyl group), a tert-butyl group (tBu), or a1, 1-dimethyl-3, 3-dimethyl-butyl group, and particularly preferably a methyl group, an ethyl group, or a tert-butyl group.

Examples of the 1-valent alicyclic hydrocarbon group having 3 to 20 carbon atoms include monocyclic saturated hydrocarbon groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclodecyl, methylcyclohexyl, and ethylcyclohexyl; monocyclic unsaturated hydrocarbon groups such as cyclobutenyl, cyclopentenyl, cyclohexenyl, cycloheptenyl, cyclooctenyl, cyclodecenyl, cyclopentadienyl, cyclohexadienyl, cyclooctadienyl and cyclodecadiene; bicyclo [2.2.1]Heptyl, bicyclo [2.2.2]Octyl, tricyclo [5.2.1.0^2，6]Decyl, tricyclo [3.3.1.1^3，7]Decyl, tetracyclic [6.2.1.1^3，6.0^2，7]And polycyclic saturated hydrocarbon groups such as dodecyl and adamantyl.

Specific examples of the 1-valent aromatic hydrocarbon group having 6 to 20 carbon atoms include a phenyl group, a 2, 6-diethylphenyl group, a naphthyl group, and a biphenyl group, with an aryl group having 6 to 12 carbon atoms (particularly, a phenyl group) being preferred.

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like, and among them, a fluorine atom, a chlorine atom or a bromine atom is preferable.

On the other hand, as R⁶～R⁹、R^XAnd R^YSpecific examples of the alkyl group having 1 to 6 carbon atoms include methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, and n-hexyl groups.

And in the above formula (Ar-2) and the above formula (Ar-3), A³And A⁴Each independently represents a group selected from the group consisting of-O-, -N (R)¹⁰) A radical of the group consisting of-S-and-CO-, R¹⁰Represents a hydrogen atom or a substituent. Examples of the substituent include Y in the above formula (Ar-1)¹The aromatic hydrocarbon group having 6 to 12 carbon atoms and the aromatic heterocyclic group having 3 to 12 carbon atoms may have the same substituent.

In the formula (Ar-2), X represents a hydrogen atom or a non-metal atom of groups 14 to 16 to which a substituent may be bonded.

Examples of the group 14 to 16 non-metal atom represented by X include an oxygen atom, a sulfur atom, a substituted nitrogen atom, and a substituted carbon atom, and specific examples of the substituent include an alkyl group, an alkoxy group, an alkyl-substituted alkoxy group, a cyclic alkyl group, an aryl group (e.g., phenyl group, naphthyl group, etc.), a cyano group, an amino group, a nitro group, an alkylcarbonyl group, a sulfo group, a hydroxyl group, and the like.

And, in the above formula (Ar-3), D³And D⁴Each independently represents a single bond, -CO-O-, -C (═ S) O-, -CR¹R²-、-CR¹R²-CR³R⁴-、-O-CR¹R²-、-CR¹R²-O-CR³R⁴-、-CO-O-CR¹R²-、-O-CO-CR¹R²-、-CR¹R²-O-CO-CR³R⁴-、-CR¹R²-CO-O-CR³R⁴-、-NR¹-CR²R³-or-CO-NR¹-。R¹、R²、R³And R⁴Each independently represents a hydrogen atom, a fluorine atom or an alkyl group having 1 to 4 carbon atoms.

As the above-mentioned R¹、R²、R³And R⁴The alkyl group having 1 to 4 carbon atoms may be linear, branched or cyclic, and specific examples thereof include methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl and tert-butyl.

And, in the above formula (Ar-3), SP³And SP⁴Each independently represents a single bond, a linear or branched alkylene group having 1 to 12 carbon atoms, or at least 1-CH constituting a linear or branched alkylene group having 1 to 12 carbon atoms₂A linking group having a valence of 2, which is substituted by-O-, -S-, -NH-, -N (Q) -or-CO-, wherein Q represents a substituent.

As the above SP³And SP⁴Examples of the linear or branched alkylene group having 1 to 12 carbon atoms represented by the formula (1) include SP¹And SP²The same groups as those described in (1).

Examples of the substituent represented by Q include the same as Y in the above formula (Ar-1)¹The aromatic hydrocarbon group having 6 to 12 carbon atoms and the aromatic heterocyclic group having 3 to 12 carbon atoms may have the same substituent.

And, in the above formula (Ar-3), L³And L⁴Each independently represents an organic group having a valence of 1, L³And L⁴And L in the above formula (1)¹And L²At least one of (a) and (b) represents a polymerizable group.

As the above-mentioned L³And L⁴Examples of the 1-valent organic group represented by the formula (1) include¹And L²The same groups as those described in (1).

Further, examples of the polymerizable group include L in the above formula (1)¹And L²The same groups as those described in (1).

In the formulae (Ar-4) and (Ar-5), Ax represents an organic group having 2 to 30 carbon atoms having at least 1 aromatic ring selected from the group consisting of an aromatic hydrocarbon ring and an aromatic heterocyclic ring.

In the formulae (Ar-4) and (Ar-5), Ay represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms which may have a substituent, or an organic group having 2 to 30 carbon atoms of at least one aromatic ring selected from the group consisting of an aromatic hydrocarbon ring and an aromatic heterocyclic ring.

Here, the aromatic ring in Ax and Ay may have a substituent, or Ax and Ay may be bonded to each other to form a ring.

And in the above formula (Ar-4) and the above formula (Ar-5), Q³Represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms which may have a substituent.

Ax and Ay are groups described in paragraphs [0039] to [0095] of patent document 2 (International publication No. 2014/010325).

And as Q³Specific examples of the alkyl group having 1 to 6 carbon atoms include methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, and n-hexyl groups. And as Q³Examples of the substituent which may be contained in the C1-6 alkyl group include the same as Y in the formula (Ar-1)¹The aromatic hydrocarbon group having 6 to 12 carbon atoms and the aromatic heterocyclic group having 3 to 12 carbon atoms may have the same substituent.

As the specific polymerizable liquid crystal compound, the following compounds are preferable because the ClogP value is high and the moisture and heat durability of the formed optically anisotropic film is more excellent: in the above formula (1), m is 1, A¹And G¹All of which are optionally substituted cyclohexylene, E¹Is a single bond, n is 1, A²And G²All are optionally substituted cyclohexylene, and E²Is a single bond.

In the formula (1), Ar is Ar because of its high ClogP value and its better moisture/heat durability¹Preferably represented by the formula (Ar-1) or the formula (Ar-2)The groups shown.

Further, Ar in the above formula (1) is used for the reason that the light resistance is more excellent¹Derived from the structure of (HO-Ar)¹The pKa of the diphenol compound represented by-OH is preferably 11 or less.

Here, pKa is a value of an acid dissociation constant in a mixed solvent of Tetrahydrofuran (THF)/water in a volume ratio of 6/4 at 25 ℃.

As a method for measuring the acid dissociation constant in the present invention, an alkali titration method described in pages 215 to 217 of the second edition of the experimental chemistry lecture published by MARUZEN co.

As the specific polymerizable liquid crystal compound, for example, compounds represented by the following formulae (1-1) to (1-14) are preferable, and specifically, as K (side chain structure) in the following formulae (1-1) to (1-14), compounds having side chain structures shown in the following tables 1 and 2 can be cited, respectively.

In tables 1 and 2, each "+" indicated in the side chain structure of K indicates a bonding position to an aromatic ring.

In the side chain structures represented by 1-2 in table 1 and 2-2 in table 2, the groups adjacent to the acryloyloxy group and the methacryloyl group respectively represent propylene groups (groups obtained by substituting ethylene with methyl groups), and represent a mixture of positional isomers in which the methyl groups are different in position.

[ chemical formula 3]

[ Table 1]

[ Table 2]

Other polymerizable Compound

The polymerizable liquid crystal composition may contain another polymerizable compound having 1 or more polymerizable groups in addition to the specific polymerizable liquid crystal compound.

The polymerizable group of the other polymerizable compound is not particularly limited, and examples thereof include a (meth) acryloyl group, a vinyl group, a styryl group, and an allyl group. Among the polymerizable groups, (meth) acryloyl groups are preferable.

The other polymerizable compound is preferably another polymerizable compound having 1 to 4 polymerizable groups, and more preferably another polymerizable compound having 2 to 4 polymerizable groups, from the viewpoint of further improving the durability of the formed optically anisotropic film.

Examples of such other polymerizable compounds include compounds represented by the formulae (M1), (M2) and (M3) described in paragraphs [0030] to [0033] of Japanese patent laid-open No. 2014-077068, and more specifically, specific examples described in paragraphs [0046] to [0055] of Japanese patent laid-open No. 2014-077068.

In addition, a known polymerizable liquid crystal compound may be added to adjust the wavelength dispersion and the refractive index anisotropy and to adjust the liquid crystal phase transition temperature of the coating film. Examples of such polymerizable liquid crystal compounds include various polymerizable liquid crystal compounds described in "liquid crystal overview" (edited by the liquid crystal overview committee, MARUZEN co., Ltd.).

Polymerization initiator

The polymerizable liquid crystal composition preferably contains a polymerization initiator.

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

Examples of the photopolymerization initiator include an α -carbonyl compound (described in each specification of U.S. Pat. Nos. 2367661 and 2367670), an acyloin ether (described in each specification of U.S. Pat. No. 2448828), an α -hydrocarbon-substituted aromatic acyloin compound (described in each specification of U.S. Pat. No. 2722512), a polyquinone compound (described in each specification of U.S. Pat. Nos. 3046127 and 2951758), a combination of a triarylimidazole dimer and p-aminophenyl ketone (described in each specification of U.S. Pat. No. 3549367), an acridine and phenazine compound (described in each specification of Japanese patent publication No. 60-105667 and U.S. Pat. No. 4239850), an oxadiazole compound (described in each specification of U.S. Pat. No. 4212970), and an acylphosphine oxide compound (described in each of Japanese patent publication No. 63-040799, Japanese patent publication No. 5-029234, a-phosphine oxide compound (described in each specification of Japanese patent publication No, Japanese patent laid-open Nos. H10-095788 and H10-029997).

In the present invention, from the viewpoint of further improving the moist heat durability, the polymerization initiator is preferably an oxime type polymerization initiator, and more preferably a polymerization initiator represented by the following formula (I).

[ chemical formula 4]

In the above formula (I), X²Represents a hydrogen atom or a halogen atom.

And, in the above formula (I), Ar³Represents a 2-valent aromatic group, D⁵Represents a C1-12 organic group with a valence of 2.

And, in the above formula (I), R¹¹Represents an alkyl group having 1 to 12 carbon atoms, Y²Represents an organic group having a valence of 1.

In the above formula (I), as X²Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like, and among them, a chlorine atom is preferable.

In the above formula (I), Ar is a constituent³The aromatic ring having a 2-valent aromatic group represented by the formula (I) includes, for example, aromatic hydrocarbon rings such as benzene ring, naphthalene ring, anthracene ring and phenanthroline ring; and aromatic heterocycles such as furan ring, pyrrole ring, thiophene ring, pyridine ring, thiazole ring and benzothiazole ring.

In the above formula (I), D is⁵The C1-12 organic group having a valence of 2 includes, for example, C1-12 linear or branched organic groupsAlkylene groups, specifically, methylene, ethylene or propylene are preferable.

And, in the above formula (I), R is¹¹The alkyl group having 1 to 12 carbon atoms is preferably a methyl group, an ethyl group or a propyl group.

In the above formula (I), Y represents²Examples of the 1-valent organic group include those having a benzophenone skeleton ((C)₆H₅)₂CO) functional groups. Specifically, as in the groups represented by the following formula (Ia) and the following formula (Ib), a functional group containing a benzophenone skeleton in which a terminal benzene ring is unsubstituted or monosubstituted is preferable. In the following formulae (Ia) and (Ib), a bonding position, that is, a bonding position to a carbon atom of a carbonyl group in the formula (I) is represented.

[ chemical formula 5]

Examples of the oxime type polymerization initiator represented by the formula (I) include a compound represented by the following formula (S-1) and a compound represented by the following formula (S-2).

[ chemical formula 6]

The polymerization initiator may be used alone in 1 kind or in combination of 2 or more kinds.

The content of the polymerization initiator (the total content thereof when a plurality of types are included) in the polymerizable composition is not particularly limited, but is preferably 0.01 to 20% by mass, more preferably 0.5 to 5% by mass of the solid content of the polymerizable liquid crystal composition.

Solvents

From the viewpoint of workability in forming an optically anisotropic film, etc., it is preferable that the polymerizable liquid crystal composition contains a solvent.

As the solvent, specifically, examples thereof include ketones (e.g., acetone, 2-butanone, methyl isobutyl ketone, cyclohexanone, and cyclopentanone), ethers (e.g., dioxane, tetrahydrofuran, etc.), aliphatic hydrocarbons (e.g., hexane, etc.), alicyclic hydrocarbons (e.g., cyclohexane, etc.), aromatic hydrocarbons (e.g., toluene, xylene, trimethylbenzene, etc.), halogenated carbons (e.g., dichloromethane, dichloroethane, dichlorobenzene, and chlorotoluene, etc.), esters (e.g., methyl acetate, ethyl acetate, and butyl acetate, etc.), water, alcohols (e.g., ethanol, isopropanol, butanol, cyclohexanol, etc.), cellosolves (e.g., methyl cellosolve and ethyl cellosolve, etc.), cellosolve acetates, sulfoxides (e.g., dimethyl sulfoxide, etc.), and amides (e.g., dimethylformamide, dimethylacetamide, etc.).

The organic solvent may be used alone in 1 kind, or may be used in combination in 2 or more kinds.

Levelling agent

From the viewpoint of keeping the surface of the optically anisotropic film smooth and facilitating alignment control, it is preferable that the polymerizable liquid crystal composition contains a leveling agent.

As such a leveling agent, a fluorine-based leveling agent or a silicon-based leveling agent is preferable because the leveling effect is high with respect to the amount added, and a fluorine-based leveling agent is more preferable because bleeding (blooming, bleeding) is less likely to occur.

As the leveling agent, specifically, examples thereof include compounds described in paragraphs [0079] to [0102] of Japanese patent laid-open No. 2007-069471, compounds represented by the general formula (I) (particularly, compounds described in paragraphs [0020] to [0032 ]) described in Japanese patent laid-open No. 2013-047204, compounds represented by the general formula (I) (particularly, compounds described in paragraphs [0022] to [0029 ]) described in Japanese patent laid-open No. 2012-211306, liquid crystal alignment promoters described in general formula (I) (particularly, compounds described in paragraphs [0076] to [0078] and [0082] to [0084 ]) described in Japanese patent laid-open No. 2002-129162, and compounds represented by the general formulae (I), (II) and (III) (particularly, compounds described in paragraphs [0092] 0096 ]) described in Japanese patent laid-open No. 2005-099248. Further, the functional group may also function as an alignment control agent described later.

Orientation control agent

The polymerizable liquid crystal composition may further contain an alignment controlling agent, if necessary.

The orientation control agent can form various orientation states such as a tilt orientation, a hybrid orientation, and a cholesteric orientation in addition to a uniform orientation, and can control and realize a specific orientation state more uniformly and more precisely.

As the orientation control agent for promoting uniform orientation, for example, a low molecular orientation control agent and a high molecular orientation control agent can be used.

As the low-molecular orientation controlling agent, for example, the descriptions of paragraphs [0009] to [0083] of Japanese patent laid-open publication No. 2002-.

Further, as the orientation controlling agent for the polymer, for example, the paragraphs [0021] to [0057] of Japanese patent laid-open No. 2004-198511 and the paragraphs [0121] to [0167] of Japanese patent laid-open No. 2006-106662 are referred to and are incorporated herein by reference.

When the polymerizable liquid crystal composition contains an orientation control agent, the content of the orientation control agent (the total content thereof when a plurality of the orientation control agents are contained) is preferably 0.01 to 10% by mass, and more preferably 0.05 to 5% by mass, based on the total solid content in the polymerizable liquid crystal composition. When the content of the orientation controlling agent is within this range, an optically anisotropic film which realizes a desired orientation state, is free from precipitation, phase separation, orientation defects, and the like, and is uniform and has high transparency can be obtained.

These alignment control agents may further have a polymerizable functional group, particularly a polymerizable functional group capable of polymerizing with a specific polymerizable liquid crystal compound constituting the polymerizable liquid crystal composition used in the present invention.

Other ingredients

The polymerizable liquid crystal composition may contain other components in addition to the above components. Examples of the other components include liquid crystal compounds other than the polymerizable liquid crystal compounds, surfactants, tilt angle control agents, alignment aids, plasticizers, and crosslinking agents. As the orientation assistant, HYSORB MTEM (manufactured by Toho Chemical industry Co., Ltd.) and NK ester A-200 (manufactured by Shin-Nakamura Chemical Co., Ltd.) are preferable.

[ optical alignment film ]

The photo-alignment film constituting the optical film of the present invention is a photo-alignment film formed using a thermally crosslinkable photo-alignment film-forming composition containing a photo-alignment copolymer described later.

The thickness of the photo-alignment layer is not particularly limited and may be appropriately selected according to the purpose, but is preferably 10 to 1000nm, and more preferably 10 to 700 nm. Within this range, it is possible to provide a sufficient alignment regulating force, and even if there are irregularities or other foreign matter on the surface of the polymer support, it is possible to flatten the surface of the alignment film, and to achieve uniform alignment of the liquid crystal compound constituting the optically anisotropic film.

(photo-alignment copolymer)

The photo-alignment copolymer contained in the photo-alignment film according to the present invention includes a photo-alignment repeating unit represented by formula (A) and a thermal crosslinkable repeating unit represented by formula (B), and has a thermal crosslinkable group equivalent of 340 to 500. The photo-alignment repeating unit represented by the following formula (a) is a repeating unit including a photo-alignment group, and the thermal-crosslinkable repeating unit represented by the following formula (B) is a repeating unit including a thermal-crosslinkable group.

Here, the equivalent weight of the thermally crosslinkable group means the mass of the solid content containing 1 mole of the thermally crosslinkable group described later. For example, when an epoxy group is used as the thermally crosslinkable group, the epoxy equivalent is equivalent to that described in JIS K7236. When a hydroxyl group and a free acid group are used as the thermally crosslinkable group, the hydroxyl group equivalent or the free acid equivalent (mol) per 1g of the solid content can be determined by using the titration method described in JIS K0700, and the thermally crosslinkable group equivalent can be determined by taking the reciprocal thereof. The polymer solid component is a component having a molecular weight of more than 3000 out of the total solid components contained in the composition for forming a photo-alignment film.

[ chemical formula 7]

In the formula (A) and the formula (B), B¹And B²Each independently represents-O-, -CO-O-, -O-CO-O-, or phenylene,

R¹and R²Each independently represents a hydrogen atom or a methyl group,

Sp¹and Sp²Each independently represents a single bond or a 2-valent linking group composed of 1 or more members selected from the group consisting of a linear or branched alkylene group which may have a substituent, an alicyclic alkylene group which may have a substituent, and an aromatic group which may have a substituent, and in the alkylene group which may have a substituent and the alicyclic alkylene group which may have a substituent, any carbon atom may be substituted with an ether bond, an ester bond, an amide bond, a urethane bond, and a carbonate bond, but the bond with B¹And B²The connecting part (C) does not form an-O-bond.

P²Represents a thermally crosslinkable group, and is characterized in that,

Cin¹represents a photo-alignment group represented by the following formula (3-1) or formula (3-2),

[ chemical formula 8]

In formula (3-1) or formula (3-2), represents a compound with Sp¹The bonding position of (a) to (b),

wherein, in Cin¹When the photo-alignment group represented by the formula (3-2) is represented, the formula (3-2) and Sp²The connecting portion of (A) does not become an-O-bond.

R³Represents a substituent.

In the formula (A), from Sp¹And Sp²Among the 2-valent linking groups represented, the number of carbon atoms in the linear or branched alkylene group is preferably 1 to 12, more preferably 1 to 12Preferably 1 to 8, and more preferably 1 to 6. The alicyclic alkylene group preferably has 1 to 12 carbon atoms. Examples of the aromatic ring constituting the aromatic group include aromatic hydrocarbon rings such as benzene ring, naphthalene ring, anthracene ring, and phenanthroline ring; and aromatic heterocycles such as furan ring, pyrrole ring, thiophene ring, pyridine ring, thiazole ring and benzothiazole ring.

Examples of the substituent which the linear or branched alkylene group, the alicyclic alkylene group and the aromatic group may have include the same as those mentioned for Y in the above formula (Ar-1)¹The aromatic hydrocarbon group having 6 to 12 carbon atoms and the aromatic heterocyclic group having 3 to 12 carbon atoms may have the same substituent.

As a result of Sp¹And Sp²Among the 2-valent linking groups, a linear or branched alkylene group is preferable.

In the formula (A), from P²The definition of the thermally crosslinkable group is as follows.

In the formula (3-1) or the formula (3-2), examples of the substituent represented by R3 include Y in the formula (Ar-1)¹The aromatic hydrocarbon group having 6 to 12 carbon atoms and the aromatic heterocyclic group having 3 to 12 carbon atoms may have the same substituent.

The photo-alignment film in the optical film of the present invention is formed from the photo-alignment film-forming composition containing the photo-alignment copolymer, and therefore, even when disposed on a polymer support in a thin film thickness, the photo-alignment film can sufficiently exert an alignment regulating force on a liquid crystal compound. The optically anisotropic film formed on the photo-alignment film using the polymerizable liquid crystal composition exhibits a uniform alignment state in which alignment disorder is suppressed. Although the details of the reason are not clear, the present inventors presume as follows.

In the production of the optical film of the present invention, after a photo-alignment film is provided on a polymer support, a polymerizable liquid crystal composition is further applied to the photo-alignment film. At this time, the solvent contained in the coating film of the polymerizable liquid crystal composition transmits through the photo-alignment film to extract a hydrophobic low-molecular-weight component derived from the polymer support to the coating film side. In particular, in the present invention, since the load of the CLogP value of the liquid crystal compound constituting the polymerizable liquid crystal composition is on average high and therefore the affinity to the hydrophobic component is high, a relatively large amount of hydrophobic low-molecular-weight component derived from the polymer support can be extracted into the coating film. Supposedly: when the hydrophobic low-molecular weight component derived from the polymer support is extracted into the coating film, the optical anisotropic film obtained by curing the coating film is affected by the occurrence of alignment defects that can be visually recognized due to the breakdown of the interaction between the liquid crystal molecules, the deterioration of the reverse wavelength dispersibility due to the partial randomization of the refractive index anisotropy of the liquid crystal molecules, and the like. In contrast, it can be presumed that: by preventing the extraction of a hydrophobic low-molecular-weight component derived from the polymer support into the coating film, a favorable alignment state can be obtained.

When the thermally crosslinkable group equivalent of the photo-alignment copolymer is 500 or less (that is, when the content of the thermally crosslinkable group contained in 1g of the composition is large), the content of the thermally crosslinkable group is sufficient and the above-described extraction inhibiting effect can be sufficiently exhibited. In addition, when the thermal crosslinkable group equivalent of the photo-alignment copolymer is 340 or more (that is, when the content of the thermal crosslinkable group contained in 1g of the composition is small), the area ratio of the photo-alignment groups occupied on the surface of the photo-alignment film is large, and the photo-alignment film can exhibit a high alignment restriction force by imparting an appropriate degree of mobility to the photo-alignment film. Further, it is presumed that: when the equivalent of the thermally crosslinkable group is in the range of 340 to 500, these 2 effects can be simultaneously achieved.

Further, although details are not clear, it is presumed that the structure of the photo-alignment copolymer also contributes to the extraction inhibiting effect.

In the present specification, the thermally crosslinkable group means, for example, an oxirane group, an oxetanyl group, a 3, 4-epoxycyclohexyl group, an amide group, an N-alkoxymethyl group, an N-hydroxymethyl group, a phenolic hydroxyl group, a carboxyl group and a hydroxyl group. Among them, an oxirane group, an oxetanyl group and a 3, 4-epoxycyclohexyl group are referred to as chain polymerizability in the present specification because they can be chain polymerized under cationic polymerization conditions.

The photo-alignment copolymer may contain other repeating units in addition to the repeating unit represented by the above formula (a) and the repeating unit represented by the above formula (B) as long as the effect of the present invention is not impaired.

Examples of the monomer forming such another repeating unit include radical polymerizable monomers. Examples of the radical polymerizable monomer include an acrylate compound, a methacrylate compound, a maleimide compound, an acrylamide compound, acrylonitrile, maleic anhydride, a styrene compound, and a vinyl compound.

In addition, when the photo-alignment copolymer contains a repeating unit other than the repeating unit represented by the above formula (a) and the repeating unit represented by the above formula (B), the total content of the repeating unit represented by the above formula (a) and the repeating unit represented by the above formula (B) is preferably 70 mol% or more, more preferably 80 mol% or more, further preferably 90 mol% or more, and particularly preferably 95 mol% or more, with respect to all the repeating units of the photo-alignment copolymer. The upper limit is not particularly limited, but may be less than 100 mol%.

The method for synthesizing the photo-alignment copolymer is not particularly limited, and for example, the photo-alignment copolymer can be synthesized by mixing a monomer forming the repeating unit represented by the above formula (a), a monomer forming the repeating unit represented by the above formula (B), and a monomer forming an arbitrary other repeating unit, and polymerizing the mixture in an organic solvent using a radical polymerization initiator.

The weight average molecular weight (Mw) of the photo-alignment copolymer is preferably 10,000 to 500,000, more preferably 25,000 to 200,000, and still more preferably 25,000 or more and less than 50,000, from the viewpoint of improving the alignment property.

Here, the weight average molecular weight and the number average molecular weight in the present invention are values measured by a Gel Permeation Chromatography (GPC) method under the conditions shown below.

Solvent (eluent): THF (tetrahydrofuran)

Device name: TOSOH HLC-8320GPC

Column: 3 TOSOH TSKgel Super HZM-H (4.6 mm. times.15 cm) were ligated and used

Column temperature: 40 deg.C

Sample concentration: 0.1% by mass

Flow rate: 1.0mL/min

Calibration curve: calibration curves obtained using 7 samples of TSK standard polystyrene manufactured by Tosoh Corporation, Mw 2800000-1050 (Mw/Mn 1.03-1.06)

The content of the photo-alignment copolymer in the composition for forming a photo-alignment film is not particularly limited, but when the composition for forming a photo-alignment film contains an organic solvent described later, the content is preferably 0.1 to 50 parts by mass, and more preferably 0.5 to 10 parts by mass, relative to 100 parts by mass of the organic solvent.

(solvent)

The composition for forming a photo-alignment film used in the present invention preferably contains an organic solvent from the viewpoint of workability in producing a photo-alignment film.

As the organic solvent, specifically, for example, examples thereof include ketones (e.g., methyl ethyl ketone, acetone, 2-butanone, methyl isobutyl ketone, cyclohexanone, cyclopentanone, etc.), ethers (e.g., dioxane, tetrahydrofuran, etc.), aliphatic hydrocarbons (e.g., hexane, etc.), alicyclic hydrocarbons (e.g., cyclohexane, etc.), aromatic hydrocarbons (e.g., toluene, xylene, trimethylbenzene, etc.), halogenated carbons (e.g., dichloromethane, dichloroethane, dichlorobenzene, chlorotoluene, etc.), esters (e.g., methyl acetate, ethyl acetate, butyl acetate, etc.), water, alcohols (e.g., ethanol, isopropanol, butanol, cyclohexanol, etc.), cellosolves (e.g., methyl cellosolve, ethyl cellosolve, etc.), cellosolve acetates, sulfoxides (e.g., dimethyl sulfoxide, etc.), and amides (e.g., dimethylformamide, dimethylacetamide, etc.).

As the organic solvent, 1 kind of them may be used alone, or 2 or more kinds may be used simultaneously.

(other Components)

The composition for forming a photo-alignment film may further contain other components than those described above, and examples thereof include a polymer compound, a crosslinking agent or a crosslinking reaction initiator, a polymer crosslinking catalyst, an adhesion improving agent, a leveling agent, and a sensitizer. These compounds may further have a functional group capable of reacting with the photo-alignment copolymer.

In the case of using a photo-alignment copolymer containing only a chain-polymerizable thermal-crosslinkable group selected from the group consisting of an ethylene oxide group, an oxetanyl group, and a 3, 4-epoxycyclohexyl group as a thermal-crosslinkable group, it is preferable that the composition for forming a photo-alignment film further contains a thermal polymerization initiator (preferably a thermal cationic polymerization initiator) as a thermal-crosslinking reaction initiator, from the viewpoint of achieving a sufficient crosslinking reaction in a short time by a roll-to-roll process. In the case of using a photo-alignment copolymer containing a group selected from the group consisting of an amide group, an N-alkoxymethyl group, an N-hydroxymethyl group, a phenolic hydroxyl group, a carboxyl group, and a hydroxyl group as a thermal crosslinkable group, it is preferable that the composition for forming a photo-alignment film further contains a crosslinking agent and a crosslinking catalyst.

[ Polymer support ]

The optical film of the present invention comprises a polymeric support. For application to a roll-to-roll process, the polymer support is preferably in the form of a strip. Such a support is preferably transparent, and specifically, the light transmittance is preferably 80% or more. The upper limit of the transmittance is, for example, 100% or less.

The structure of the polymer support is not particularly limited, but may be, for example, a structure including a single-layer polymer film, or a laminate including a polymer film and a surface modification layer (for example, an easy-adhesion layer) disposed on the polymer film.

Examples of the material of such a polymer film include cellulose-based polymers; acrylic polymers such as acrylic polymers having an acrylate polymer, such as polymethyl methacrylate and polymers containing a lactone ring; a thermoplastic norbornene-based polymer; a polycarbonate-series polymer; polyester polymers such as polyethylene terephthalate and polyethylene naphthalate; styrene polymers such AS polystyrene and acrylonitrile-styrene copolymer (AS resin); polyolefin polymers such as polyethylene, polypropylene and ethylene-propylene copolymers; a vinyl chloride polymer; amide polymers such as nylon and aromatic polyamide; an imide polymer; a sulfone-based polymer; a polyether sulfone-based polymer; a polyether ether ketone polymer; polyphenylene sulfide-based polymer; a vinylidene chloride polymer; a vinyl alcohol polymer; a vinyl butyral polymer; an aryl ester polymer; a polyoxymethylene polymer; an epoxy polymer; and polymers obtained by mixing these polymers.

Further, a polarizer described later may also serve as the support.

In particular, in the embodiment in which the polymer support is used as a part of the optical film, the polymer constituting the polymer support is preferably a cellulose-based polymer, an acrylic-based polymer, or a thermoplastic norbornene-based polymer, from the viewpoint that transparency, adhesiveness to other members, and birefringence can be controlled from zero to any direction and size. That is, as the polymer support, a film containing a cellulose-based polymer, a film containing an acrylic-based polymer, or a film containing a thermoplastic norbornene-based polymer is preferable. Among them, cellulose acylate films are more preferable as the polymer support.

In addition, in the embodiment in which the polymer support is easily peelable and only the optically anisotropic film is transferred to a polarizing plate or an image display device and used, a film containing a cellulose-based polymer or a polyethylene terephthalate film is preferable from the viewpoint of excellent film strength and easy availability.

The thickness of the polymer support is not particularly limited, but is preferably 5 to 60 μm, and more preferably 5 to 30 μm.

(cellulose acylate film)

As a preferable embodiment of the polymer support, a cellulose acylate film can be used. The cellulose acylate is an acylate in which a hydroxyl group of cellulose is acylated, and any of an acetyl group having 2 carbon atoms to an acetyl group having 22 carbon atoms of an acyl group can be used as a substituent.

The acyl group having 2 to 22 carbon atoms, which is a substituent for the hydroxyl group of the cellulose, is not particularly limited, and may be an aliphatic group, an aromatic group, a single acyl group, or a mixture of 2 or more acyl groups. Examples of the cellulose acylate in which these groups are substituted include an alkylcarbonyl ester of cellulose, an alkenylcarbonyl ester of cellulose, an aromatic carbonyl ester of cellulose, and an aromatic alkylcarbonyl ester of cellulose, each of which may have a further substituted group.

Examples of the acyl group include an acetyl group, a propionyl group, a butyryl group, a benzoyl group, a naphthoyl group, and a cinnamoyl group. Among them, acetyl, propionyl, butyryl, benzoyl, naphthoyl, or cinnamoyl is preferable, and acetyl, propionyl, or butyryl is more preferable. In particular, from the viewpoints of ease of synthesis, cost, ease of controlling the distribution of substituents, and the like, acetyl or propionyl is more preferable, and acetyl is particularly preferable. When 2 or more kinds of acyl groups are substituted, a combination of an acetyl group and a propionyl group is preferable.

In the cellulose acylate, the degree of substitution with acyl groups for hydroxyl groups of cellulose is not particularly limited, but when the cellulose acylate is used for applications such as a polarizing plate protective film and an optical film, various additives are preferably compatible with each other under a condition of high degree of substitution with acyl groups. Therefore, the degree of substitution (total degree of substitution) of the hydroxyl group in the cellulose with an acyl group is preferably 2.50 to 3.00, more preferably 2.70 to 2.96, and still more preferably 2.80 to 2.95. When only acetyl groups are substituted in the cellulose acylate, the degree of substitution of the acetyl groups is preferably 2.70 to 2.96, more preferably 2.80 to 2.95. When only propionyl groups are substituted in the cellulose acylate, the substitution degree of the propionyl groups is preferably 0.20 to 2.60.

In the cellulose acylate, the degree of substitution (degree of substitution with acyl group) of acetic acid and/or a fatty acid having 3 to 22 carbon atoms which substitute for a hydroxyl group of cellulose is measured by a method according to ASTM D-817-91 and an NMR (nuclear magnetic resonance) method.

In the cellulose acylate film, as the cellulose acylate, a single cellulose acylate or a mixture of 2 or more different cellulose acylates can be used from the viewpoint of a substituent group, a substitution degree, a polymerization degree, a molecular weight distribution, and the like.

The cellulose acylate film may further contain an additive. Examples of the additives include plasticizers, hydrophobizing agents, ultraviolet absorbers, and retardation regulators. Specific examples of the additive include polyester oligomers, sugar ester compounds, and phosphate ester compounds. As described later, when the cellulose acylate film also functions as a polarizer protective film, a polyester oligomer or a sugar ester compound is preferable from the viewpoint of excellent moisture and heat resistance.

The polyester oligomer has a repeating unit comprising a dicarboxylic acid and a diol, and can be synthesized by a known method such as a dehydration condensation reaction of a dicarboxylic acid and a diol, or an addition and dehydration condensation reaction of a dicarboxylic anhydride to a diol.

As the dicarboxylic acid, an aliphatic dicarboxylic acid and an aromatic dicarboxylic acid can be used. Examples of the aliphatic dicarboxylic acid include oxalic acid, malonic acid, succinic acid, maleic acid, fumaric acid, glutaric acid, adipic acid, and 1, 4-cyclohexanedicarboxylic acid. Examples of the aromatic dicarboxylic acid include phthalic acid, isophthalic acid, terephthalic acid, and 1, 4-naphthalenedicarboxylic acid.

The diol (ethylene glycol) includes aliphatic or alicyclic diols having 2 to 12 carbon atoms, alkyl ether diols having 4 to 20 carbon atoms, and aromatic ring-containing diols having 6 to 20 carbon atoms, and 2 or more selected from these diols may be used together. The number of carbon atoms of the aromatic diol is preferably 6 to 12.

Both ends of the above polyester oligomer are preferably sealed at least one end. Among them, the terminal is preferably selected from the group consisting of carbon atom number 1 ~ 22 aliphatic group, carbon atom number 6 ~ 20 aromatic ring containing group, carbon atom number 1 ~ 22 aliphatic carbonyl and carbon atom number 6 ~ 20 aromatic carbonyl in at least 1.

When both ends are sealed, the polyester oligomer is hard to be in a solid state at room temperature, and the handling property is good. As a result, a polymer film having excellent humidity stability and polarizing plate durability can be obtained.

The content of the polyester oligomer as an additive (the total content thereof when a plurality of polyester oligomers are contained) in the cellulose acylate film is preferably 1 to 30% by mass, more preferably 5 to 20% by mass, and still more preferably 5 to 15% by mass, based on the cellulose acylate.

The sugar ester compound refers to a compound in which at least 1 of the groups (for example, hydroxyl group and carboxyl group) that can be substituted in the sugar skeleton structure constituting the compound is ester-bonded to at least 1 substituent. That is, the sugar ester compound as referred to herein also includes sugar derivatives in a broad sense, and for example, also includes a sugar residue such as gluconic acid as a structure. That is, the sugar ester compound further includes an ester of glucose and a carboxylic acid and an ester of gluconic acid and an alcohol.

The sugar ester compound is preferably a sugar ester compound obtained by alkyl-esterifying all or a part of OH groups of the compound (M) having 1 furanose structure or pyranose structure, or a sugar ester compound obtained by alkyl-esterifying all or a part of OH groups of the compound (D) having 2 furanose structures or pyranose structures bonded to at least 1. More preferably, the sugar ester compound is a monocyclic ring having a furanose structure or a pyranose structure, and is obtained by alkyl-esterifying all or a part of the hydroxyl groups of the structure, and still more preferably, the sugar ester compound is obtained by alkyl-esterifying all or a part of the hydroxyl groups of the glucose structure.

Examples of the compound (M) include glucose, galactose, mannose, fructose, xylose, and arabinose, with glucose or fructose being preferred, and glucose being more preferred.

Examples of the compound (D) include lactose, sucrose, nystose, 1F-nystose, stachyose, maltitol, lactitol, lactulose, cellobiose, maltose, cellotriose, maltotriose, raffinose and kestose. Further, gentiobiose, gentiotriose, gentiotetraose, xylotriose, galactosucrose, and the like can be given.

Among these compounds (D), a compound having both a furanose structure and a pyranose structure is particularly preferable, sucrose, kestose, nystose, 1F-kestose or stachyose is more preferable, and sucrose is further preferable.

In order to alkyl-esterify all or a part of the OH groups in the compound (M) and the compound (D), an aliphatic monocarboxylic acid is preferably used.

Examples of the aliphatic monocarboxylic acid include saturated fatty acids such as acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, caproic acid, heptanoic acid, caprylic acid, nonanoic acid, decanoic acid, 2-ethyl-hexane carboxylic acid, undecanoic acid, lauric acid, tridecanoic acid, myristic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, stearic acid, nonadecanoic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, heptacosanoic acid, fulvic acid, melissic acid, and lacca acid; and unsaturated fatty acids such as undecylenic acid, oleic acid, sorbic acid, linoleic acid, linolenic acid, arachidonic acid, and octenoic acid, and among them, acetic acid, propionic acid, and isobutyric acid are preferable. That is, the substituent in the sugar ester compound is preferably an acetyl group, a propionyl group, or an isobutyryl group.

The aliphatic monocarboxylic acid for alkyl-esterifying all or a part of the above OH groups may be 2 or more aliphatic monocarboxylic acids, and at least 1 of them is preferably a branched aliphatic monocarboxylic acid. Among these branched aliphatic monocarboxylic acids, isobutyric acid is more preferable.

More specifically, it is preferable to esterify all or a part of the OH groups with acetic acid and isobutyric acid. In other words, the substituent in the sugar ester compound is preferably an acetyl group or an isobutyryl group. When the substituent includes only an acetyl group and an isobutyryl group, the ratio thereof is preferably 1/7 to 4/4, more preferably 1/7 to 3/5, and still more preferably 2/6.

A process for producing an aliphatic sugar ester compound substituted with these aliphatic monocarboxylic acids is described in, for example, Japanese patent application laid-open No. 8-245678.

In the cellulose acylate film, the content of the above-mentioned additive (the total content thereof in the case where a plurality of additives are contained) is preferably 5 to 20% by mass relative to the cellulose acylate.

In the case where the optical film of the present invention is bonded to the polarizer and the polymer support, the compound represented by the following general formula (4) can be added to the cellulose acylate film to be used, from the viewpoint of suppressing the deterioration of the polarizer due to moist heat.

General formula (4)

[ chemical formula 9]

In the above general formula (4), R¹¹、R¹³And R¹⁵Each independently represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an aralkyl group having 1 to 20 carbon atoms or an aromatic group having 6 to 20 carbon atoms.

As to these compounds and the synthesis methods thereof, reference can be made to the contents of JP-A-2013-174861 (as the compounds, the compounds described in paragraphs 0090-0122 of JP-A-2013-174861).

When the cellulose acylate film contains the compound represented by the above general formula (4), the content of the compound represented by the above general formula (4) is preferably 1 to 20% by mass relative to the cellulose acylate polymer.

The cellulose acylate film preferably contains fine particles as a matting agent. As the fine particles, silica, titania, alumina, zirconia, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, magnesium silicate, calcium phosphate, and the like can be used.

The fine particles preferably have a1 st order average particle diameter of 20nm or less and an apparent specific gravity of 70 g/liter or more. These fine particles usually form 2-order particles having an average particle diameter of 0.1 to 3.0 μm, and form irregularities of 0.1 to 3.0 μm on the surface of the film. Thus, when the optical film of the present invention is formed into a long roll in a roll-to-roll process, it is possible to prevent quality deterioration due to friction between films and/or a phenomenon (also referred to as blocking) in which the films adhere to each other.

The fine particles may be added so as to provide unevenness on both surfaces of the cellulose acylate film, but depending on the need to flatten the surface of the photo-alignment film in order to control the orientation of the optically anisotropic film, it is preferable to add the fine particles so as to provide unevenness only on the surface of the cellulose acylate film opposite to the side on which the photo-alignment film is provided.

(polyethylene terephthalate film)

In the present specification, the polyethylene terephthalate film refers to a film containing polyethylene terephthalate as a main component. The polyethylene terephthalate is a polyester having a repeating unit derived from terephthalic acid as a dicarboxylic acid component and a repeating unit derived from ethylene glycol as a diol component, and 80 mol% or more of all the repeating units are repeating units derived from ethylene terephthalate, and may further contain a repeating unit derived from another copolymerizable component as necessary.

As a method for producing polyethylene terephthalate, in addition to a so-called direct polymerization method in which terephthalic acid, ethylene glycol, and if necessary, another dicarboxylic acid and/or another diol are directly reacted, any production method such as a so-called transesterification method in which a dimethyl ester of terephthalic acid, ethylene glycol, and if necessary, another dimethyl ester of a dicarboxylic acid and/or another diol are subjected to a transesterification reaction can be applied.

In order to be able to effectively form various functional layers, the polyethylene terephthalate film may have a surface modification layer on the surface thereof. As such a surface modification layer, a layer coated with various binder resins can be used. Examples of the binder resin include polyester resins, acrylic resins, polyurethane resins, polyalkylene glycols, polyalkylene imines, methyl cellulose, and carboxyl cellulose, and among them, polyester resins, acrylic resins, and polyurethane resins are preferable. If necessary, a crosslinking agent such as a melamine compound, an epoxy compound, an oxazoline compound, an isocyanate compound, or a carbodiimide compound can be used together.

The surface modification layer can be provided by various known methods. For example, in the case of on-line coating, a film provided with a surface-modified layer can be obtained by preparing the above-mentioned components such as the binder resin and the crosslinking agent into an aqueous solution or aqueous dispersion, and applying a coating liquid having a solid content concentration adjusted to about 0.1 to 50% by mass onto a polyethylene terephthalate film.

The surface-modified layer has a film thickness of usually 0.002 to 1.0. mu.m, preferably 0.03 to 0.5. mu.m, more preferably 0.04 to 0.2. mu.m. Within the above range, a sufficient surface modification function can be expressed, and the occurrence of blocking and the increase in haze can be suppressed.

[ other layers ]

The optical film of the present invention may further include other functional layers in addition to the above-described optically anisotropic film, photo-alignment film and polymer support. Examples of the functional layer include an adhesive layer, a hard coat layer, an optically anisotropic film other than those described above, and a colored layer. Examples of the method of providing the functional layer include a method of separately producing the functional layer and then transferring the functional layer via an adhesive layer, and a method of separately providing the functional layer on a support and bonding the functional layer to the support. Another method for providing the functional layer includes a method in which a coating liquid for forming the functional layer is directly applied to a surface of an optically anisotropic film constituting the optical film of the present invention opposite to the photo-alignment film or a surface of a polymer support constituting the optical film of the present invention opposite to the photo-alignment film.

In the optical film of the present invention, the optically anisotropic film may be provided so as to be peelable. In the case where the optical anisotropic film is provided so as to be peelable, the optical anisotropic film may be peeled off at the interface between the photo alignment film and the optical anisotropic film (in other words, the optical anisotropic film may be provided so as to be peelable on the photo alignment film), and the optical anisotropic film may be peeled off at the interface between the photo alignment film and the polymer support (in other words, the photo alignment film may be provided so as to be peelable on the polymer support). Among them, peeling at the interface between the photo alignment film and the optically anisotropic film is preferable.

[ Process for producing optical film ]

The optical film of the present invention is formed by providing a photo-alignment film on a polymer support, applying a polymerizable liquid crystal composition to the photo-alignment film, applying an alignment treatment, and fixing the alignment state by a polymerization reaction. A schematic diagram of these processes is shown in fig. 3. From the viewpoint of productivity, it is preferable to use a roll-to-roll process as shown in fig. 3.

(formation of photo-alignment film)

The photo-alignment film can be produced by a conventionally known production method, in addition to using the above-described composition for forming a photo-alignment film.

As an example of the method for producing the photo-alignment film, there is a method for producing the photo-alignment film, including: a coating step of coating the photo-alignment film-forming composition on a surface of a polymer support to form a coating film; a heating step of thermally crosslinking the coating film by heating; and a light irradiation step of irradiating the heated coating film with polarized light or irradiating the surface of the heated coating film with unpolarized light from an oblique direction. The above-described production method may further include a heating step after the light irradiation step, as necessary.

The following describes the above-described manufacturing method with reference to fig. 3.

Coating Process

The coating method in the coating step is not particularly limited and may be appropriately selected according to the purpose, and examples thereof include spin coating, die coating, gravure coating, flexographic printing, inkjet printing, and the like.

In fig. 3, the polymer support 1 unwound from the roll of the polymer support was coated with a die 32.

Heating Process

The heating method in the heating step is not particularly limited, and the polymer support with a coating film obtained through the coating step may be heated by a known method.

Examples of the heating method include: a method of heating the coated polymer support by exposure to a heating environment; a method of heating a polymer support with a coating film by contacting with a conveying roller or the like through which a heat-supplying medium flows; and a method of heating the polymer support with the coating film by irradiating a heat ray. The heating temperature is preferably 30 to 200 ℃.

By appropriately controlling the removal of the solvent in the coating film and the thermal crosslinking reaction of the photo-alignment film during the heating process, the adhesion of the polymer support to the photo-alignment film is enhanced, and the orientation control of the optical anisotropic film can be improved by controlling the extraction of a hydrophobic low molecular weight component derived from the polymer support.

In fig. 3, the polymer support with the coating film is heated by the heating device 33.

Procedure for light irradiation

In the light irradiation step, the polarized light to be irradiated to the coating film after the heating is not particularly limited, and examples thereof include linearly polarized light, circularly polarized light, elliptically polarized light, and the like, and among them, linearly polarized light is preferable.

The "inclination direction" to which unpolarized light is irradiated is not particularly limited as long as it is a direction inclined by a polar angle θ (0 < θ < 90 °) with respect to the normal direction of the surface of the coating film, and may be appropriately selected according to the purpose, but θ is preferably 20 to 80 °.

The wavelength of the polarized light or the unpolarized light is not particularly limited as long as it is a wavelength capable of controlling the alignment of the liquid crystalline molecules contained in the coating film after the heating, but examples thereof include ultraviolet rays, near ultraviolet rays, and visible rays. Among them, near ultraviolet rays of 250nm to 450nm are preferable.

Examples of the light source for irradiating polarized light or unpolarized light include xenon lamps, high-pressure mercury lamps, ultrahigh-pressure mercury lamps, and metal halide lamps. By applying an interference filter, a color filter, or the like to the ultraviolet rays and the visible rays from such a light source, the wavelength range to be irradiated can be appropriately adjusted. By applying a polarizing filter and a polarizing prism to the light from these light sources, linearly polarized light can be obtained.

The cumulative amount of polarized or unpolarized light is not particularly limited as long as it is a wavelength at which the alignment of the liquid crystal molecules contained in the coating film after heating can be controlled, but is preferably 1 to 300mJ/cm²More preferably 5 to 100mJ/cm²。

The illuminance of polarized light or unpolarized light is not particularly limited as long as it is a wavelength at which the alignment of liquid crystal molecules contained in the coating film after heating can be controlled, but is preferably 0.1 to 300mW/cm²More preferably 1 to 100mW/cm²。

As shown in fig. 3, when the coating film after the heating is irradiated with light, it is preferable to provide a support roller 38 for preventing the polymer support 1 from wobbling with respect to the light source, from the viewpoint of preventing unevenness or variation in the alignment of the liquid crystal molecules contained in the coating film.

(formation of optically Anisotropic film)

Examples of the method for forming the optically anisotropic film include a method in which the polymerizable liquid crystal composition is used to set a desired alignment state, and then the composition is fixed by polymerization. Typically, a coating step of coating a polymerizable liquid crystal composition on a photo-alignment film to form a coating film, an alignment-curing step of bringing liquid crystal molecules such as a specific polymerizable liquid crystal compound contained in the coating film into a desired alignment state, and an alignment-fixing step of fixing the alignment state by polymerization are sequentially performed, and various known methods can be applied to the coating method and the alignment-curing method.

In the orientation fixing step, the polymerization conditions are not particularly limited, but in the polymerization by light irradiation, ultraviolet rays are preferably used. The irradiation dose is preferably 10mJ/cm²～50J/cm²More preferably 20mJ/cm²～5J/cm²More preferably 30mJ/cm²～3J/cm²Particularly preferably 50 to 1000mJ/cm². And areFurther, the polymerization reaction may be carried out under heating to accelerate the polymerization reaction. The exposure method can use various known methods.

As shown in fig. 3, the step of forming the optically anisotropic film is preferably performed continuously with the step of forming the photo-alignment film. In fig. 3, the step of applying the polymerizable liquid crystal composition is performed by a die 35, the step of curing the alignment is performed by a heating device 36, and the step of fixing the alignment is performed by exposure treatment using a light source 37. In the roll-to-roll process, the manufactured optical film can be rolled up into a roll (roll) 39.

[ optical characteristics of optical film ]

The optical film of the present invention can impart various optical characteristics depending on the purpose thereof.

As a preferable mode, the optically anisotropic film can be a positive a plate. Here, the a plate is defined in the following manner.

When the refractive index in the slow axis direction (direction in which the in-plane refractive index is largest) in the optically anisotropic film is nx, the refractive index in the direction orthogonal to the slow axis in the plane is ny, and the refractive index in the thickness direction is nz, the positive a plate satisfies the relationship of formula (a 1).

Formula (A1) nx > ny ≈ nz

The term "substantially" as used herein includes not only the case where both are completely identical but also the case where both are substantially identical. The term "substantially the same" is included in "ny ≈ nz" even when (ny-nz). times.d (where d is the thickness of the thin film) is-10 to 10nm, preferably-5 to 5nm, and is included in "nx ≈ nz" even when (nx-nz). times.d is-10 to 10nm, preferably-5 to 5 nm.

Typically, the positive a plate can be obtained by horizontal alignment (uniform alignment) of a rod-like liquid crystal compound. In the present invention, the specific polymerizable liquid crystal compound is a rod-like liquid crystal compound, and horizontal alignment is performed on the photo-alignment film, whereby the positive a plate can be obtained.

The optically anisotropic film constituting the optical film of the present invention can satisfy the following formula (3) or formula (4) by using the above-mentioned specific polymerizable liquid crystal compound. Further, it preferably satisfies the following formula (5).

Re(450)/Re(550)＜1......(3)

Rth(450)/Rth(550)＜1......(4)

0.50＜Re(450)/Re(550)＜1.00......(5)

In the above formulas (3) and (5), Re (450) represents the in-plane retardation of the optically anisotropic film at a wavelength of 450nm, and Re (550) represents the in-plane retardation of the optically anisotropic film at a wavelength of 550 nm. In the present specification, when the measurement wavelength of retardation is not specified, the measurement wavelength is 550 nm.

In the above formula (4), Rth (450) represents the retardation in the thickness direction of the optically anisotropic film at a wavelength of 450nm, and Rth (550) represents the retardation in the thickness direction of the optically anisotropic film at a wavelength of 550 nm.

In the present invention, the values of the in-plane retardation and the retardation in the thickness direction are values measured using light of a measurement wavelength using AxoScan OPMF-1 (manufactured by OptoScience, inc.).

Specifically, the average refractive index ((Nx + Ny + Nz)/3) and the film thickness (d (μm)) were input by using the AxoScan OPMF-1 to calculate as follows:

slow axis direction (°)

Re(λ)＝R0(λ)

Rth(λ)＝((nx+ny)/2-nz)×d。

R0 (. lamda.) is a numerical value calculated by Axoscan OPMF-1, but refers to Re (. lamda.).

When the optically anisotropic film is a positive A plate, Re (550) is preferably 100 to 180nm, more preferably 120 to 160nm, further preferably 130 to 150nm, and particularly preferably 130 to 140nm, from the viewpoint of functioning as an 1/4 wavelength plate. Within this range, an optically anisotropic film that can convert polarized light of 1/4 wavelengths in a wide frequency band in the visible light region can be obtained by satisfying the above formula (3) or formula (5).

The polymeric support may be of any optical character.

For example, it may be that nx ≈ ny ≈ nz as a preferable mode. As for nx, ny and nz mentioned herein, the definition of the optical anisotropy is replaced with that of the polymer support. That is, Re (550) may be-10 to 10nm, preferably-5 to 5nm, and Rth (550) may be-10 to 10nm, preferably-5 to 5 nm. In the case where polarized light is incident from the side of the optically anisotropic film, the polarization state of light emitted from the optically anisotropic film through the polymer support may be changed by considering only polarization conversion by the optically anisotropic film, which is advantageous in that optical design is easy.

Alternatively, the polymeric support may be a positive a plate, a negative biaxial plate, a positive C plate, or a negative C plate. And, it is possible to express an optical anisotropy of nx > nz > ny.

In this case, the amount of the solvent to be used,

a positive A plate: nx is greater than ny and is approximately equal to nz

Negative A plate: nz ≈ nx > ny

Negative biaxial plate: nx > ny > nz

Positive biaxial plate: nz > nx > ny

And C, positive plate: nx ≈ ny < nz

And (3) negative C plate: nx ≈ ny > nz

The optical anisotropy of the optically anisotropic film and the polymer support can be appropriately designed according to the use of the optical film of the present invention as described later.

[ polarizing plate ]

The polarizing plate can be formed by bonding the optical film of the present invention and a polarizer.

In the case where the optically anisotropic film of the optical film of the present invention can be peeled from the photo-alignment film, the polarizing plate can be formed even by bonding the optically anisotropic film transferred from the optical film to a polarizer. As an example of using such a polarizing plate, a circular polarizing plate with a positive C plate 18 schematically shown in fig. 2 (in fig. 2, the adhesive layer is not shown).

[ polarizer ]

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

As the absorption polarizer, an iodine-based polarizer, a dye-based polarizer using a dichroic dye, a polyene-based polarizer, and the like can be used. The iodine-based polarizer and the dye-based polarizer can be used as both a coated polarizer and a stretched polarizer, but a polarizer produced by adsorbing iodine or a dichroic dye onto polyvinyl alcohol and stretching the adsorbed iodine or dichroic dye is preferable.

Further, as a method for obtaining a polarizer by stretching and dyeing a laminated film in which a polyvinyl alcohol layer is formed on a substrate, there can be mentioned japanese patent No. 5048120, japanese patent No. 5143918, japanese patent No. 4691205, japanese patent No. 4751481, and japanese patent No. 4751486, and the like, and known techniques related to these polarizers can be preferably used.

As the reflective polarizer, a polarizer obtained by laminating thin films having different birefringence, a wire grid polarizer, a polarizer obtained by combining a cholesteric liquid crystal having a selective reflection region and an 1/4 wavelength plate, and the like can be used.

Among them, from the viewpoint of more excellent adhesion, the polarizer preferably contains a polyvinyl alcohol resin (containing-CH as a repeating unit)₂-CHOH-polymer, in particular at least 1 selected from the group comprising polyvinyl alcohol and ethylene-vinyl alcohol copolymer. ) The polarizer of (4).

The thickness of the polarizer is not particularly limited, but is preferably 3 μm to 60 μm, more preferably 5 μm to 30 μm, and still more preferably 5 μm to 15 μm.

[ adhesive layer ]

These polarizing plates may have an adhesive layer disposed between the optically anisotropic film transferred from the optical film of the present invention and the polarizer.

The pressure-sensitive adhesive layer used for laminating an optically anisotropic film and a polarizer includes, for example, a material having a ratio (tan ═ G "/G ') of storage modulus G' to loss elastic modulus G ″ measured by a dynamic viscoelasticity measuring apparatus of 0.001 to 1.5, and includes a so-called pressure-sensitive adhesive, a material that is easily subject to creep, and the like. Examples of the binder that can be used in the present invention include, but are not limited to, a polyvinyl alcohol-based binder.

[ image display apparatus ]

The optical film of the present invention can be incorporated into an image display device by directly incorporating the optical film or by incorporating the optical film by peeling the optically anisotropic film.

The display element used in these image display devices is not particularly limited, and examples thereof include a liquid crystal cell, an organic electroluminescence (hereinafter, abbreviated as "EL") display panel, a plasma display panel, and a micro LED (light emitting diode) display panel.

For example, when applied to a liquid crystal cell, the film can be used as an optical compensation film or a viewing angle compensation film. When applied to a self-light emitting display device such as an EL display panel, a plasma display panel, or a micro LED display panel, the retardation of the optical anisotropic film is set to λ/4 wavelength, the slow axis thereof is combined with the absorption axis of the linear polarizer at 45 ° to form a circularly polarizing plate, and the polarizer/(polymer support/photo alignment film)/optical anisotropic film/display device are arranged in this order (the description of the adhesive layer and the like is omitted), whereby the function of preventing light reflected by external light inside the panel from reaching the observer can be provided.

Examples

The present invention will be described in further detail below based on examples. The materials, amounts, ratios, processing contents, processing procedures and the like shown in the following examples can be appropriately changed without departing from the gist of the present invention. Therefore, the scope of the present invention should not be construed restrictively by the examples shown below.

Hereinafter, SK-2057 (manufactured by Soken Chemical & Engineering Co., Ltd.) was used as an adhesive unless otherwise specified.

EXAMPLE 1

(Synthesis of Polymer PA-1 having a thermally crosslinkable group and a photo-alignable group)

The monomer m-1 shown below was synthesized according to the method described in Langmuir, 32(36), 9245-9253 (2016), using 2-hydroxyethyl methacrylate (HEMA) (a reagent manufactured by Tokyo Chemical Industry Co., Ltd.) and the following cinnamoyl chloride derivative.

Cinnamoyl chloride derivatives

[ chemical formula 10]

Monomer m-1

[ chemical formula 11]

5 parts by mass of 2-butanone as a solvent was charged into a flask equipped with a cooling tube, a thermometer, and a stirrer, and the mixture was refluxed by heating in a water bath while flowing nitrogen gas into the flask at 5 mL/min. Here, a solution obtained by mixing 5 parts by mass of monomer M-1, 5 parts by mass of CYCLOMER M100(3, 4-epoxycyclohexylmethyl methacrylate, manufactured by Daicel corporation), 1 part by mass of 2, 2' -azobis (isobutyronitrile) as a polymerization initiator, and 5 parts by mass of 2-butanone as a solvent was added dropwise over 3 hours, and further stirred while maintaining a reflux state for 3 hours. After the reaction, the reaction mixture was naturally cooled to room temperature, and 30 parts by mass of 2-butanone was added and diluted, thereby obtaining a polymer solution of about 20 mass%. The obtained polymer solution was put into a large excess of methanol to precipitate a polymer, and the recovered precipitate was filtered off and washed with a large amount of methanol, followed by air-drying at 50 ℃ for 12 hours, thereby obtaining a polymer PA-1 having a thermal crosslinkable group and a photo-alignment group. The obtained polymer PA-1 had an epoxy equivalent of 396 and a weight average molecular weight of 28,000.

[ chemical formula 12]

(preparation of photo-alignment film P-1)

The following composition PC-1 for forming a photo-alignment film was continuously applied to [0120] passing Japanese unexamined patent publication No. 2018-124528 using a wire bar of #2.4]～[0122]The additive-containing polymer support (specifically, an additive-containing cellulose acylate film) produced by the method described in the paragraph. Then, the support having the coating film formed thereon was dried with warm air at 140 ℃ for 120 seconds, and then irradiated with polarized ultraviolet light (10 mJ/cm)²An ultra-high pressure mercury lamp is used), thereby forming the photo-alignment film P-1.

The polymer support contains, as additives, a polyester compound B described in examples of jp 2015-227955 a (specifically, a polyester oligomer (number average molecular weight: 850) having repeating units (molar ratios of 50 mol% each) containing 1, 2-cyclohexanedicarboxylic acid and ethylene glycol, and having a structure in which both ends thereof are sealed with cyclohexanoyl groups), and the following compound F.

The content of the polyester compound B was 12% by mass with respect to the cellulose acylate polymer, and the content of the compound F was 2% by mass with respect to the cellulose acylate polymer.

Compound F

[ chemical formula 13]

(formation of optical film 1)

The following polymerizable liquid crystal composition A-1 was applied to the photo-alignment film P-1 using a bar coater. The coating film formed on the photo-alignment film P-1 was heated to 180 ℃ with warm air, then cooled to 120 ℃ and irradiated at a wavelength of 365nm to 100mJ/cm using a high-pressure mercury lamp under a nitrogen atmosphere²Thereby fixing the orientation of the liquid crystal compound, and a polymer laminated in this order was preparedAn optical film 1 comprising a support, a photo-alignment film P-1 and an optically anisotropic film A-1. Re (550) of the optically anisotropic film A-1 was 144nm, which is a positive A plate showing optical anisotropy of nx > ny ≈ nz.

The load average of the CLogP value of each of the liquid crystal compounds contained in the polymerizable liquid crystal composition a-1 is shown in table 3.

In the polymerizable liquid crystal composition A-1, the polymerizable liquid crystal compound L-2 and the mesogenic compound A-1 correspond to liquid crystal compounds.

[ chemical formula 14]

(formation of Positive C plate C-1)

A film C1 was produced, which was formed on a dummy support for formation, on a positive C plate C-1 (wherein the thickness of the positive C plate was controlled so that Rth (550) became-69 nm) produced by the same method as the positive C plate described in paragraph [0124] of Japanese patent laid-open No. 2015-200861).

(formation of circular polarizing plate 1)

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

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

The obtained polarizer was bonded to a support (TD80UL) subjected to alkali saponification treatment, and a polarizing plate with the polarizer exposed on one side was obtained.

Next, the surface of the polarizer exposed to the polarizer and the surface of the optically anisotropic film a-1 were bonded to each other with an adhesive so that the absorption axis of the polarizer and the slow axis of the optically anisotropic film a-1 became 45 °, and only the positive a plate a-1 was transferred to the polarizer by peeling the photo-alignment film and the polymer support of the optical film 1 from the polarizer. Then, the surface of the positive C plate C-1 in the film C-1 was bonded to the surface of the transferred positive a plate a-1 using an adhesive, and the dummy support for forming the film C1 was peeled off, whereby only the positive C plate C-1 was transferred to the optically anisotropic film a-1, and the circularly polarizing plate 1 was produced.

EXAMPLE 2

An optical film 2 was produced and then a circularly polarizing plate 2 was produced in the same manner as in example 1 except that the polymerizable liquid crystal composition a-1 was changed to the following polymerizable liquid crystal composition a-2 and the thickness was adjusted so that Re (550) became 144nm to form an optically anisotropic film a-2. It is a positive A plate in which the refractive index anisotropy of the optically anisotropic film A-2 is nx > ny ≈ nz.

The load average of the CLogP value of each of the liquid crystal compounds contained in the polymerizable liquid crystal composition a-2 is shown in table 3.

In the polymerizable liquid crystal composition A-2, the polymerizable liquid crystal compound L-1, the polymerizable liquid crystal compound L-2 and the mesogenic compound A-1 correspond to liquid crystal compounds.

EXAMPLE 3

An optical film 3 was produced and then a circularly polarizing plate 3 was produced in the same manner as in example 1 except that the polymerizable liquid crystal composition a-1 was changed to the following polymerizable liquid crystal composition a-3 and the thickness was adjusted so that Re (550) became 144nm to form an optically anisotropic film a-3. It is a positive A plate in which the refractive index anisotropy of the optically anisotropic film A-3 is nx > ny ≈ nz.

The load average of the CLogP value of each of the liquid crystal compounds contained in the polymerizable liquid crystal composition a-3 is shown in table 3.

In the polymerizable liquid crystal composition A-3, the polymerizable liquid crystal compound L-1 and the mesogenic compound A-1 correspond to liquid crystal compounds.

EXAMPLE 4

An optical film 4 was produced and then a circularly polarizing plate 4 was produced in the same manner as in example 1 except that the polymerizable liquid crystal composition a-1 was changed to the following polymerizable liquid crystal composition a-4 and the thickness was adjusted so that Re (550) became 144nm to form an optically anisotropic film a-4. It is a positive A plate in which the refractive index anisotropy of the optically anisotropic film A-4 is nx > ny ≈ nz.

The load average of the CLogP value of each of the liquid crystal compounds contained in the polymerizable liquid crystal composition a-4 described below is shown in table 3.

In the polymerizable liquid crystal composition A-4, the polymerizable liquid crystal compound L-2 and the mesogenic compound A-1 correspond to liquid crystal compounds.

EXAMPLE 5

A positive a plate a-5 was produced and a circularly polarizing plate 5 was produced in the same manner as in example 1, except that the polymerizable liquid crystal composition a-1 was changed to the following polymerizable composition a-5 and the thickness was adjusted.

The load average of the CLogP value of each of the liquid crystal compounds contained in the polymerizable liquid crystal composition a-5 is shown in table 3.

In the polymerizable liquid crystal composition A-5, the polymerizable liquid crystal compound L-3 corresponds to a liquid crystal compound.

[ chemical formula 15]

Comparative example 1

A positive a plate a-11 was produced and a circularly polarizing plate 11 was produced in the same manner as in example 1, except that the polymerizable liquid crystal composition a-1 was changed to the following polymerizable liquid crystal composition a-11 and the thickness was adjusted.

The load average of the CLogP value of each of the liquid crystal compounds contained in the polymerizable liquid crystal compositions a to 11 described below is shown in table 3.

In the polymerizable liquid crystal composition A-11, the polymerizable liquid crystal compound L-4, the polymerizable liquid crystal compound L-5 and the mesogenic compound A-2 correspond to liquid crystal compounds.

[ chemical formula 16]

Comparative example 2

An optical film 12 and a circularly polarizing plate 12 were produced in the same manner as in example 1, except that the composition PC-2 for forming a photoalignment film, which used the polymer PA-2 synthesized by the following method in place of the polymer PA-1 having the thermal crosslinkable group and the photoalignment group of example 1, was used.

(Synthesis of Polymer PA-2 having a thermally crosslinkable group and a photo-alignable group)

5 parts by mass of 2-butanone as a solvent was charged into a flask equipped with a cooling tube, a thermometer, and a stirrer, and the mixture was refluxed by heating in a water bath while flowing nitrogen gas into the flask at 5 mL/min. Here, a solution obtained by mixing 6.5 parts by mass of monomer M-1, 3.5 parts by mass of CYCLOMER M100 (manufactured by Daicel Co corporation), 1 part by mass of 2, 2' -azobis (isobutyronitrile) as a polymerization initiator, and 5 parts by mass of 2-butanone as a solvent was added dropwise over 3 hours, and further stirred while maintaining a reflux state for 3 hours. After the reaction, the reaction mixture was naturally cooled to room temperature, and 30 parts by mass of 2-butanone was added and diluted, thereby obtaining a polymer solution of about 20 mass%. The obtained polymer solution was put into a large excess of methanol to precipitate a polymer, and the recovered precipitate was filtered off and washed with a large amount of methanol, followed by air-drying at 50 ℃ for 12 hours, thereby obtaining a polymer PA-2 having a thermal-crosslinkable group and a photo-alignment group. The obtained polymer PA-2 had an epoxy equivalent of 566 and a weight average molecular weight of 28,000.

[ chemical formula 17]

Comparative example 3

An optical film 13 and a circularly polarizing plate 13 were produced in the same manner as in example 1, except that the composition PC-3 for forming a photoalignment film, which used the polymer PA-3 synthesized by the following method in place of the polymer PA-1 having the thermal crosslinkable group and the photoalignment group of example 1, was used.

(Synthesis of Polymer PA-3 having a thermally crosslinkable group and a photo-alignable group)

5 parts by mass of 2-butanone as a solvent was charged into a flask equipped with a cooling tube, a thermometer, and a stirrer, and the mixture was refluxed by heating in a water bath while flowing nitrogen gas into the flask at 5 mL/min. Here, a solution obtained by mixing 4 parts by mass of monomer M-1, 6 parts by mass of CYCLOMER M100 (manufactured by Daicel corporation), 1 part by mass of 2, 2' -azobis (isobutyronitrile) as a polymerization initiator, and 5 parts by mass of 2-butanone as a solvent was added dropwise over 3 hours, and further stirred while maintaining a reflux state for 3 hours. After the reaction, the reaction mixture was naturally cooled to room temperature, and 30 parts by mass of 2-butanone was added and diluted, thereby obtaining a polymer solution of about 20 mass%. The obtained polymer solution was put into a large excess of methanol to precipitate a polymer, and the recovered precipitate was filtered off and washed with a large amount of methanol, followed by air-drying at 50 ℃ for 12 hours, thereby obtaining a polymer PA-3 having a thermal crosslinkable group and a photo-alignment group. The obtained polymer PA-3 had an epoxy equivalent of 330 and a weight average molecular weight of 28,000.

[ chemical formula 18]

Reference example 1

A laminate G1 in which the photo-alignment film GP-1 and the optically anisotropic film GA-1 were formed in this order on a glass substrate was produced in the same manner as in example 1, except that a glass substrate was used instead of the polymer support, and the thickness of the optically anisotropic film was adjusted so that Re (550) became 144 nm. Next, a circularly polarizing plate was produced in the same manner as in example 1. It is a positive A plate in which the refractive index anisotropy of the optically anisotropic film GA-1 is nx > ny ≈ nz.

Reference example 2

A laminate G2 in which the photo-alignment film GP-2 and the optically anisotropic film GA-2 were formed in this order on a glass substrate was produced in the same manner as in reference example 1, except that the photo-alignment film-forming composition PC-2 was used instead of the photo-alignment film-forming composition PC-1. Next, a circularly polarizing plate was produced in the same manner as in example 1. It is a positive A plate in which the refractive index anisotropy of the optically anisotropic film GA-2 is nx > ny ≈ nz.

EXAMPLE 6

(Synthesis of Polymer PA-4 having a thermally crosslinkable group and a photo-alignable group)

In the synthesis of the polymer PA-1 of example 1, 6 parts by mass of the monomer M-1 and 4 parts by mass of OXE-10 (methyl 3-ethyloxetan-3-yl) acrylate, manufactured by Osaka Organic Chemical Industry Co., Ltd., were used instead of 5 parts by mass of the monomer M-1 and 5 parts by mass of CYCLOMER M100, and a polymer PA-4 was obtained.

(preparation of composition PC-4 for Forming photo-alignment film)

A photo alignment film forming composition PC-4 was prepared in the same manner as in example 1, except that the polymer PA-4 was used instead of the polymer PA-1 in the preparation of the photo alignment film forming composition PC-1.

[ production of optical film ]

An optical film 6 was produced in the same manner as in example 1 except that the composition PC-4 for forming a photo-alignment film was used instead of the composition PC-1 for forming a photo-alignment film, and then a circularly polarizing plate 6 was produced.

EXAMPLE 7

(Synthesis of Polymer PA-5 having a thermally crosslinkable group and a photo-alignable group)

In the synthesis of the polymer PA-1 of example 1, 6 parts by mass of the monomer M-1 and 4 parts by mass of glycidyl methacrylate (manufactured by Tokyo Chemical Industry Co., Ltd.) were used instead of 5 parts by mass of the monomer M-1 and 5 parts by mass of the CYCLOMER M100, to obtain a polymer PA-5.

(preparation of composition PC-5 for Forming photo-alignment film)

A photo alignment film forming composition PC-5 was prepared in the same manner as in example 1, except that the polymer PA-5 was used instead of the polymer PA-1 in the preparation of the photo alignment film forming composition PC-1.

(production of optical film 7)

An optical film 7 was produced in the same manner as in example 1 except that the composition PC-5 for forming a photo-alignment film was used instead of the composition PC-1 for forming a photo-alignment film, and then a circularly polarizing plate 7 was produced.

< evaluation of liquid Crystal alignment >

The optical film thus produced was placed on a polarizing microscope, and after the polarizing plate was crossed nicols, the angle of the optical film was adjusted and the film was set at the extinction position. Microscopic observation was performed in this state, 10 fields of view were observed while changing the position of the 500 μm × 500 μm region, and the average value of the number of bright spots observed therein was evaluated as an index of liquid crystal alignment. The evaluation criteria are as follows.

A: the number of bright spots observed in the 500. mu. m.times.500. mu.m area is less than 3 on average

D: the number of bright spots observed in a 500. mu. m.times.500. mu.m area is 3 or more on average

Evaluation of durability

An adhesive was applied to the prepared front a plate to prepare an adhesive-attached front a plate, and the ReA (550) after holding the plate at 85 ℃ for 500 hours in an 85% atmosphere was evaluated according to the following criteria.

A: the proportion of the ReA (550) after the retention at 85 ℃ and 85% to the ReA (550) before the retention is 98% or more

B: the proportion of the ReA (550) after retention at 85 ℃ and 85% to the ReA (550) before retention is 95% or more and less than 98%

C: the proportion of ReA (550) after 85 ℃ and 85% holding to ReA (550) before holding is 90% or more and less than 95%

D: the proportion of ReA (550) after retention at 85 ℃ and 85% relative to ReA (550) before retention is less than 90%

(mounting on organic EL display device)

GALAXY S IV manufactured by SAMSUNG company, which mounted an organic EL display panel, was disassembled, the circular polarizing plates were peeled off, and the circular polarizing plates manufactured in examples, comparative examples, and reference examples were respectively bonded to the organic EL display panel, thereby manufacturing an organic EL display device. The circularly polarizing plates 1 to 7, G1 and G2 produced in examples and reference examples and the circularly polarizing plate 11 produced in comparative example 1 exhibited a front reflection color tone of nearly neutral black and a transmission reflection color tone in the 45 ° direction at the time of black display, but the polarizing plates 12 and 13 produced in comparative examples 2 and 3 also exhibited bright spots at the time of black display and were perceived to be colored in front reflection and transmission reflection in the 45 ° direction as compared with neutral black.

The optically anisotropic films among the optical films of examples showed reverse wavelength dispersibility, and showed excellent wet heat durability. The optically anisotropic film exhibits orientation properties equivalent to those of reference example 1 (corresponding to an example using a glass support) in which extraction of a hydrophobic low-molecular-weight component does not occur even when the film is placed on a polymer support containing a hydrophobic low-molecular-weight component. That is, the optical film of the present invention is suitable for a roll-to-roll process, and it is apparent that the optically anisotropic film exhibits excellent optical characteristics and moisture-heat durability.

Description of the symbols

10-optical film, 3, 12-optically anisotropic film, 2, 14-photo-alignment film, 1, 16-polymer support, 18-positive C plate, 20-polarizer, 22-circular polarizer, 30-optical film manufacturing process, 31, 39-roll, 32, 35-mold, 33, 36-heating device, 34, 37-light source, 38-support roll.

Claims

1. An optical film comprising an optically anisotropic film formed from a polymerizable liquid crystal composition, a photo-alignment film and a polymer support in this order,

the load of the CLOGP value of each liquid crystal compound contained in the polymerizable liquid crystal composition is 10.0 to 20.0 on average,

the composition for forming a photo-alignment film comprises a photo-alignment copolymer containing a photo-alignment repeating unit represented by the following formula (A) and a thermal-crosslinkable repeating unit represented by the following formula (B), wherein the thermal-crosslinkable group equivalent of the photo-alignment copolymer is 340 to 500,

formula (1):

L¹-SP¹-(E³-A¹)_m-E¹-G¹-D¹-Ar¹-D²-G²-E²-(A²-E⁴)_n-SP²-L²

in the formula (1), D¹、D²、E¹、E²、E³And E⁴Each independently represents a single bond, -CO-O-, -C (═ S) O-, -CR¹R²-、-CR¹R²-CR³R⁴-、-O-CR¹R²-、-CR¹R²-O-CR³R⁴-、-CO-O-CR¹R²-、-O-CO-CR¹R²-、-CR¹R²-O-CO-CR³R⁴-、-CR¹R²-CO-O-CR³R⁴-、-NR¹-CR²R³-or-CO-NR¹-，R¹、R²、R³And R⁴Each independently represents a hydrogen atom, a fluorine atom or an alkyl group having 1 to 4 carbon atoms,

G¹and G²Each independently represents an optionally substituted alicyclic hydrocarbon group having a valence of 2 and having 5 to 8 carbon atoms, and 1 or more-CH constituting the alicyclic hydrocarbon group₂May be substituted by-O-, -S-or-NH-,

A¹and A²Each independently represents a 2-valent aromatic hydrocarbon group having 6 to 12 carbon atoms which may have a substituent or a 2-valent alicyclic hydrocarbon group having 5 to 8 carbon atoms which may have a substituent, and 1 or more-CH constituting the alicyclic hydrocarbon group₂May be substituted by-O-, -S-or-NH-,

SP¹and SP²Each independently represents a single bond, a linear or branched alkylene group having 1 to 12 carbon atoms, or at least 1-CH constituting a linear or branched alkylene group having 1 to 12 carbon atoms₂A linking group having a valence of 2, substituted by-O-, -S-, -NH-, -N (Q) -or-CO-, Q represents a substituent,

L¹and L²Each independently represents an organic group having a valence of 1, L¹And L²At least one of (A) and (B) represents a polymerizable group, wherein, in Ar¹In the case of an aromatic ring represented by the following formula (Ar-3), L¹And L²And L in the following formula (Ar-3)³And L⁴At least one of (a) represents a polymerizable group,

m represents an integer of 0 to 2, and when m is 2, a plurality of E³A may be the same or different, respectively¹May be the same or different from each other,

n represents an integer of 0 to 2, and when n is 2, a plurality of E⁴A may be the same or different, respectively²May be the same or different from each other,

Ar¹represents any one aromatic ring selected from the group consisting of groups represented by the following formulas (Ar-1) to (Ar-5),

in the formulae (Ar-1) to (Ar-5), each represents the same as D¹Or D²The bonding position of (a) to (b),

Q¹represents a group of N or CH,

Q²represents-S-, -O-or-N (R)⁵)-，R⁵Represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms,

Y¹represents an optionally substituted aromatic hydrocarbon group having 6 to 12 carbon atoms or an optionally substituted aromatic heterocyclic group having 3 to 12 carbon atoms,

Z¹、Z²and Z³Independently represent a hydrogen atom, a 1-valent straight chain having 1 to 20 carbon atoms orA branched aliphatic hydrocarbon group, a 1-valent alicyclic hydrocarbon group having 3 to 20 carbon atoms, a 1-valent aromatic hydrocarbon group having 6 to 20 carbon atoms, a halogen atom, a cyano group, a nitro group, -OR⁶、-NR⁷R⁸、-SR⁹、-COOR^Xor-OCOR^Y，R⁶～R⁹、R^XAnd R^YEach independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, Z¹And Z²May be bonded to each other to form an aromatic ring,

A³and A⁴Each independently represents a group selected from-O-, -N (R)¹⁰) A radical of the group consisting of-S-and-CO-, R¹⁰Represents a hydrogen atom or a substituent group,

x represents a hydrogen atom or a non-metal atom of group 14 to 16 to which a substituent may be bonded,

D³and D⁴Each independently represents a single bond, -CO-O-, -C (═ S) O-, -CR¹R²-、-CR¹R²-CR³R⁴-、-O-CR¹R²-、-CR¹R²-O-CR³R⁴-、-CO-O-CR¹R²-、-O-CO-CR¹R²-、-CR¹R²-O-CO-CR³R⁴-、-CR¹R²-CO-O-CR³R⁴-、-NR¹-CR²R³-or-CO-NR¹-，R¹、R²、R³And R⁴Each independently represents a hydrogen atom, a fluorine atom or an alkyl group having 1 to 4 carbon atoms,

SP³and SP⁴Each independently represents a single bond, a linear or branched alkylene group having 1 to 12 carbon atoms, or at least 1-CH constituting a linear or branched alkylene group having 1 to 12 carbon atoms₂A linking group having a valence of 2, substituted by-O-, -S-, -NH-, -N (Q) -or-CO-, Q represents a substituent,

L³and L⁴Each independently represents an organic group having a valence of 1, L³And L⁴And L in the formula (1)¹And L²At least 1 of (a) represents a polymerizable group,

ax represents an organic group having 2 to 30 carbon atoms having at least 1 aromatic ring selected from the group consisting of an aromatic hydrocarbon ring and an aromatic heterocyclic ring,

ay represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms which may have a substituent, or an organic group having 2 to 30 carbon atoms having at least one aromatic ring selected from the group consisting of an aromatic hydrocarbon ring and an aromatic heterocyclic ring,

the aromatic ring of Ax and Ay may have a substituent, Ax and Ay may be bonded to each other to form a ring,

Q³represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms which may have a substituent,

R¹and R²Each independently represents a hydrogen atom or a methyl group,

Sp¹and Sp²Each independently represents a single bond or a 2-valent linking group composed of 1 or more members selected from the group consisting of a linear or branched alkylene group which may have a substituent, an alicyclic alkylene group which may have a substituent, and an aromatic group which may have a substituent, and in the alkylene group which may have a substituent and the alicyclic alkylene group which may have a substituent, any carbon atom may be substituted with an ether bond, an ester bond, an amide bond, a urethane bond, and a carbonate bond, but the bond with B¹And B²The bonding portion of (A) does not form an-O-bond,

P²represents a thermally crosslinkable group, and is characterized in that,

wherein, in Cin¹When the photo-alignment group represented by the formula (3-2) is represented, the photo-alignment group represented by the formula (3-2) is bonded to Sp¹The bonding portion of (A) does not become an-O-bond,

R³represents a substituent.

2. The optical film according to claim 1,

m in the formula (1) is 1, A¹And G¹All of which are optionally substituted cyclohexylene, E¹Is a single bond, and,

n in the formula (1) is 1, A²And G²All of which are optionally substituted cyclohexylene, E²Is a single bond.

3. The optical film according to claim 1 or 2,

ar in the formula (1)¹Represents a group represented by the formula (Ar-1) or (Ar-2).

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

the thermally crosslinkable group contained in the photo-alignment copolymer is chain-polymerizable,

the composition for forming a photo-alignment film includes the photo-alignment copolymer and a thermal polymerization initiator that initiates chain polymerization of the thermal crosslinkable group.

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

the optical anisotropic film is provided so as to be peelable from the photo alignment film, or the photo alignment film is provided so as to be peelable from the polymer support.

6. A polarizing plate having the optical film of any one of claims 1 to 5 and a polarizer.

7. An image display device having the optical film of any one of claims 1 to 5 or the polarizing plate of claim 6.