JP7687066B2 - Photoreactive group-containing polymer composition, optical thin film - Google Patents

Description

The present invention relates to a polymer composition containing a photoreactive group. More specifically, the present invention relates to a polymer composition containing a photoreactive group and a retardation film containing the composition.

Retardation films are used in various image display devices from the viewpoint of expanding the viewing angle. As an existing retardation film, it is produced using a polymerizable liquid crystal compound. At this time, in order to align the polymerizable liquid crystal compound, it is necessary to provide an alignment film on the support on which the optically anisotropic layer is formed, and an alignment film that has been subjected to rubbing treatment or photoalignment treatment is used (see, for example, Patent Documents 1 to 3). However, both require complex manufacturing equipment and processes, and there are problems with the product yield. In addition, it has been proposed to form an optical thin film and a retardation film that exhibit a retardation Re/thickness of 100 nm or more by irradiating polarized ultraviolet light and heating treatment using a side-chain liquid crystal acrylate resin containing a photoreactive group without requiring an alignment film (see, for example, Patent Documents 4 and 5). However, side-chain liquid crystal acrylate resin containing a photoreactive group has problems such as being expensive because it requires multiple steps to synthesize the monomer, and having a low heat resistance temperature. Linear liquid crystal polyester resins containing photoreactive groups do not require an alignment film, and can be used to form optical thin films and retardation films by irradiation with polarized ultraviolet light and heat treatment, and are expected to produce optical thin films and retardation films with excellent heat resistance from inexpensive monomers. However, while linear liquid crystal polyester resins have excellent heat resistance, they have the problem of requiring high processing temperatures of 200 degrees or more (for example, Patent Documents 6 to 8). Therefore, when linear liquid crystal polyester resins are used as optical thin films and retardation films, there is a problem that inexpensive general-purpose resin film support substrates such as polyethylene terephthalate (heat-resistant temperature of about 160°C), polyethylene terenaphthalate (heat-resistant temperature of about 200°C), and cycloolefin polymer (heat-resistant temperature of about 160°C) cannot be used.

JP 8-160430 A Special table 2003-505561 International Publication No. 2010-150748 JP2002-226858A International Publication No. 2014-017497 Patent Publication 2018-188529 Patent Publication No. 2021-028375 Patent Publication No. 2021-028384

The present invention has been made in consideration of the above problems, and its purpose is to provide a polymer composition that is oriented even at a low heating temperature of 200°C or less and exhibits a high retardation of 100 nm or more in retardation Re/thickness.

As a result of intensive research into solving the above problems, the inventors discovered that a composition containing a polymer having a specific photoreactive group and a specific additive solves the above problems, promotes the thermal reorientation of the polymer at a heat treatment temperature below the heat resistance temperature of a general-purpose resin film support substrate, and makes it possible to manufacture the film on a general-purpose resin film support substrate, thus completing the present invention.

That is, one aspect of the present invention relates to a resin composition containing 80 to 99.99% by weight of a polymer having a structural unit A represented by the following formula (1) and at least one of a structural unit B represented by the following formula (2) or a structural unit C represented by the following formula (3), and 0.01 to 20% by weight of a thermal reorientation promoter having a molecular weight of 200 to 10,000.

(In formula (1), X ₁ to X ₃ each independently represent an aromatic ring having 5 to 7 carbon atoms which may have a substituent, or an alicyclic hydrocarbon group having 5 to 7 carbon atoms which may have a substituent, and any carbon atom in the aromatic ring or the alicyclic hydrocarbon group may be substituted with a nitrogen atom, an oxygen atom or a sulfur atom. Here, the substituents in X ₁ to X ₃ each independently represent one type of the group consisting of a halogen atom, an alkyl group having 1 to 5 carbon atoms and an alkoxy group having 1 to 5 carbon atoms, and when X ₁ to X ₃ do not have a substituent, it is a hydrogen atom. Y ₁ and Y ₂ each independently represent one type of the group consisting of -O-, -CO- and -NR ₉ -. Here, R ₉ represents one type of the group consisting of a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. _{Ar 1} and Ar Each of Ar 1 and _{Ar 2} independently represents an aromatic ring having 5 to 7 carbon atoms which may have a substituent, and any carbon atom in the aromatic ring may be substituted with a nitrogen atom, an oxygen atom, or a sulfur atom. Here, the substituents in Ar ₁ and Ar ₂ independently represent one of the group consisting of a halogen atom, an alkyl group having 1 to 5 carbon atoms, and an alkoxy group having 1 to 5 carbon atoms, and when Ar ₁ and Ar ₂ do not have a substituent, they are hydrogen atoms. Each of _{R 1} to R ₄ independently represents one of the group consisting of a hydrogen atom, a halogen atom, a cyano group, a nitro group, an alkyl group having 1 to 5 carbon atoms, and an alkoxy group having 1 to 5 carbon atoms. _{L 1} and L ₄ each represent a single bond or one of the group consisting of -O-, -NR ₅ -. Here, R ₅ represents a hydrogen atom or one of the group consisting of an alkyl group having 1 to 5 carbon atoms. _{L 2} and L ₃ each represent a single bond or -O-, -CO-O-, -CO-NR ₆ -, -CO-, -CR ₇ R ₈ -. Here, R ₆ represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. R ₇ and R ₈ each independently represent a hydrogen atom, a halogen atom, or an alkyl group having 1 to 5 carbon atoms. a and b each independently represent 0 or 1.

(In formula (2), _Y3 and _Y4 each independently represent a member selected from the group consisting of -O-, -CO-, and _-NR10- . Here, _R10 represents a member selected from the group consisting of a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. _X4 to _X6 each independently represent an aromatic ring having 5 to 7 carbon atoms which may have a substituent, or an alicyclic hydrocarbon group having 5 to 7 carbon atoms which may have a substituent, and any carbon atom in the aromatic ring or the alicyclic hydrocarbon group may be substituted with a nitrogen atom, an oxygen atom, or a sulfur atom. _R11 and _R12 each independently represent a member selected from the group consisting of a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. c represents 0 or 1.)

(In formula (3), _Y5 and _Y6 each independently represent one of the group consisting of -O-, -CO-, and _-NR13- . Here, _R13 represents one of the group consisting of a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. Z represents one of the group consisting of an alicyclic hydrocarbon group having 5 to 7 carbon atoms, a linear alkylene group having 2 to 20 carbon atoms, and a branched alkylene group having 4 to 20 carbon atoms.)

Another aspect of the present invention relates to an optical thin film containing the composition.

Another aspect of the present invention relates to a retardation film having the above-mentioned thin film.

Furthermore, another aspect of the present invention relates to a liquid crystal alignment film having the above-mentioned thin film.

The present invention provides a composition that exhibits high retardation even at a heat treatment temperature of 200°C or less and is reactive to ultraviolet light, which can be formed into a film on a general-purpose resin substrate, an optical thin film, and a retardation film made of the composition.

The composition, which is one aspect of the present invention, is described in detail below.

One embodiment of the present invention is a composition (hereinafter referred to as the "composition of the present invention") that contains 80 to 99.99% by weight of a polymer having a structural unit A represented by the following formula (1) and at least one of a structural unit B represented by the following formula (2) or a structural unit C represented by the following formula (3), and 0.01 to 20% by weight of a thermal reorientation promoter having a molecular weight of 200 to 10,000.

(In formula (1), X ₁ to X ₃ each independently represent an aromatic ring having 5 to 7 carbon atoms which may have a substituent, or an alicyclic hydrocarbon group having 5 to 7 carbon atoms which may have a substituent, and any carbon atom in the aromatic ring or the alicyclic hydrocarbon group may be substituted with a nitrogen atom, an oxygen atom or a sulfur atom. Here, the substituents in X ₁ to X ₃ each independently represent one type of the group consisting of a halogen atom, an alkyl group having 1 to 5 carbon atoms and an alkoxy group having 1 to 5 carbon atoms, and when X ₁ to X ₃ do not have a substituent, it is a hydrogen atom. Y ₁ and Y ₂ each independently represent one type of the group consisting of -O-, -CO- and -NR ₉ -. Here, R ₉ represents one type of the group consisting of a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. _{Ar 1} and Ar Each of Ar 1 and _{Ar 2} independently represents an aromatic ring having 5 to 7 carbon atoms which may have a substituent, and any carbon atom in the aromatic ring may be substituted with a nitrogen atom, an oxygen atom, or a sulfur atom. Here, the substituents in Ar ₁ and Ar ₂ independently represent one of the group consisting of a halogen atom, an alkyl group having 1 to 5 carbon atoms, and an alkoxy group having 1 to 5 carbon atoms, and when Ar ₁ and Ar ₂ do not have a substituent, they are hydrogen atoms. Each of _{R 1} to R ₄ independently represents one of the group consisting of a hydrogen atom, a halogen atom, a cyano group, a nitro group, an alkyl group having 1 to 5 carbon atoms, and an alkoxy group having 1 to 5 carbon atoms. _{L 1} and L ₄ each represent a single bond or one of the group consisting of -O-, -NR ₅ -. Here, R ₅ represents a hydrogen atom or one of the group consisting of an alkyl group having 1 to 5 carbon atoms. _{L 2} and L ₃ each represent a single bond or -O-, -CO-O-, -CO-NR ₆ -, -CO-, -CR ₇ R ₈ -. Here, R ₆ represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. R ₇ and R ₈ each independently represent a hydrogen atom, a halogen atom, or an alkyl group having 1 to 5 carbon atoms. a and b each independently represent 0 or 1.

(In formula (2), _Y3 and _Y4 each independently represent a member selected from the group consisting of -O-, -CO-, and _-NR10- . Here, _R10 represents a member selected from the group consisting of a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. _X4 to _X6 each independently represent an aromatic ring having 5 to 7 carbon atoms which may have a substituent, or an alicyclic hydrocarbon group having 5 to 7 carbon atoms which may have a substituent, and any carbon atom in the aromatic ring or the alicyclic hydrocarbon group may be substituted with a nitrogen atom, an oxygen atom, or a sulfur atom. _R11 and _R12 each independently represent a member selected from the group consisting of a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. c represents 0 or 1.)

(In formula (3), _Y5 and _Y6 each independently represent one of the group consisting of -O-, -CO-, and _-NR13- . Here, _R13 represents one of the group consisting of a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. Z represents one of the group consisting of an alicyclic hydrocarbon group having 5 to 7 carbon atoms, a linear alkylene group having 2 to 20 carbon atoms, and a branched alkylene group having 4 to 20 carbon atoms.)

In formula (1), X ₁ to X ₃ each independently represent either an aromatic ring having 5 to 7 carbon atoms which may have a substituent or an alicyclic hydrocarbon group having 5 to 7 carbon atoms which may have a substituent, and any carbon atom in the aromatic ring or the alicyclic hydrocarbon group may be substituted with a nitrogen atom, an oxygen atom, or a sulfur atom. Here, examples of the substituent in X ₁ to X ₃ include a halogen atom, an alkyl group having 1 to 5 carbon atoms, and an alkoxy group having 1 to 5 carbon atoms, and when X ₁ to X ₃ do not have a substituent, they are hydrogen atoms. X ₁ to X ₃ are preferably one member of the group consisting of a benzene ring, a methylbenzene ring, a t-butylbenzene ring, a dimethylbenzene ring, a tetrafluorobenzene ring, or a cyclohexane ring, and more preferably a trans-cyclohexane ring.

_Y1 and _Y2 each independently represent one of the group consisting of -O-, -CO-, and _-NR9- , where _R9 represents one of the group consisting of a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. _Y1 and _Y2 are preferably -O-.

Ar ₁ and Ar ₂ each independently represent an aromatic ring having 5 to 7 carbon atoms which may have a substituent, and any carbon atom in the aromatic ring may be substituted with a nitrogen atom, an oxygen atom, or a sulfur atom. Here, examples of the substituent in Ar ₁ and Ar ₂ include a halogen atom, an alkyl group having 1 to 5 carbon atoms, and an alkoxy group having 1 to 5 carbon atoms, and when Ar ₁ and Ar ₂ do not have a substituent, they are hydrogen atoms. Ar ₁ and Ar ₂ are preferably benzene rings which may have a substituent, and more preferably benzene rings.

R ₁ to R ₄ each independently represent one of the group consisting of a hydrogen atom, a halogen atom, a cyano group, a nitro group, an alkyl group having 1 to 5 carbon atoms, and an alkoxy group having 1 to 5 carbon atoms. _{R 1} to R ₄ are preferably a hydrogen atom or a cyano group, and more preferably a hydrogen atom.

_L1 and _L4 each independently represent a single bond or one of the group consisting of -O- and _-NR5- . _L1 and _L4 are preferably -O- or _-NR5- . _R5 in _L1 and _L4 represents one of the group consisting of a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. Examples of the alkyl group having 1 to 5 carbon atoms in _R5 include a methyl group, an ethyl group, a propyl group, a butyl group, and a pentyl group.

L ₂ and L ₃ each independently represent a single bond or one of the group consisting of -O-, -CO-O-, -CO-NR ₆ -, -CO-, -CR ₇ R ₈ -. However, the left-right relationship of L ₂ and L ₃ may be reversed. L ₂ and L ₃ are preferably a single bond or -CO-NR ₆ -, more preferably a single bond. R ₆ in _{L 2} and L ₃ represents one of the group consisting of a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. Examples of the alkyl group having 1 to 5 carbon atoms in R ₆ include a methyl group, an ethyl group, a propyl group, a butyl group, and a pentyl group. R ₇ and R ₈ in L ₂ and L ₃ each independently represent a hydrogen atom, a halogen atom, or one of the group consisting of an alkyl group having 1 to 5 carbon atoms. Examples of the halogen atom in _{R 7} and R ₈ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Examples of the alkyl group having 1 to 5 carbon atoms for R ₇ and R ₈ include a methyl group, an ethyl group, a propyl group, a butyl group, and a pentyl group.

a and b each independently represent 0 or 1.

In formula (2), _Y3 and _Y4 each independently represent one of the group consisting of -O-, -CO-, and _-NR10- , where _R10 represents one of the group consisting of a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. _Y3 and _Y4 are preferably -O- or -CO-.

X ₄ to X ₆ each independently represent either an aromatic ring having 5 to 7 carbon atoms which may have a substituent or an alicyclic hydrocarbon group having 5 to 7 carbon atoms which may have a substituent, and any carbon atom in the aromatic ring or the alicyclic hydrocarbon group may be substituted with a nitrogen atom, an oxygen atom, or a sulfur atom. Here, examples of the substituent in X ₄ to X ₆ include a halogen atom, an alkyl group having 1 to 5 carbon atoms, and an alkoxy group having 1 to 5 carbon atoms, and when X ₄ to X ₆ do not have a substituent, they are hydrogen atoms. X ₄ to X ₆ are preferably one member of the group consisting of a benzene ring, a methylbenzene ring, a t-butylbenzene ring, a dimethylbenzene ring, a tetrafluorobenzene ring, or a cyclohexane ring, and more preferably a benzene ring or a trans-cyclohexane ring.

_R11 and _R12 each represent a hydrogen atom or a member selected from the group consisting of an alkyl group having 1 to 5 carbon atoms. Examples of the alkyl group having 1 to 5 carbon atoms for _R5 include a methyl group, an ethyl group, a propyl group, a butyl group, and a pentyl group.

c represents 0 or 1.

In formula (3), _Y5 and _Y6 each independently represent one of the group consisting of -O-, -CO-, and _-NR13- , where _R13 represents one of the group consisting of a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. _Y5 and _Y6 are preferably -CO-.

Z represents one member of the group consisting of an alicyclic hydrocarbon group having 5 to 7 carbon atoms, a linear alkylene group having 2 to 20 carbon atoms, and a branched alkylene group having 4 to 20 carbon atoms. Z is preferably an alicyclic hydrocarbon group having 5 to 7 carbon atoms, or a linear alkylene group having 2 to 20 carbon atoms, and more preferably an alicyclic hydrocarbon group having 5 to 7 carbon atoms, or a linear alkylene group having 2 to 10 carbon atoms.

The copolymer contained in the composition of the present invention is preferably a polymer having a structural unit _A1 containing a cinnamoyl group represented by the following formula (4) and a structural unit _C1 represented by the following formula (5).

(In formula (4), _X7 and _X8 each independently represent an aromatic ring having 5 to 7 carbon atoms which may have a substituent, or an alicyclic hydrocarbon group having 5 to 7 carbon atoms which may have a substituent. _L5 represents a single bond or one of the group consisting of -O-, -CO-O-, -CO- _NR16- , -CO-, _-CR17R18- . Here, _R16 represents a hydrogen atom or an alkyl group having 1 to ₅ carbon atoms. _R17 and _R18 each independently represent one of the group consisting of a hydrogen atom, a halogen atom, or an alkyl group having 1 to 5 carbon atoms. m and l each independently represent 0 or 1. _R14 and _R15 each independently represent one of the group consisting of a hydrogen atom, a hydroxy group, a halogen atom, an alkyl group having 1 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms. _n1 and _n2 each independently represent an integer of 0 to 4.)

(In formula (5), Z represents either a linear alkylene group having 2 to 20 carbon atoms or a branched alkylene group having 4 to 20 carbon atoms.)

In the copolymer contained in the composition of the present invention, the structural unit _A1 is preferably a structural unit _A2 represented by the following formula (6).

(In formula (6), _Y7 represents one member of the group consisting of a benzene ring, a biphenyl ring, a cyclohexane ring, and a bicyclohexane ring, each of which may have a substituent. _R14 and _R15 each independently represent a hydrogen atom, a hydroxyl group, a halogen atom, an alkyl group having 1 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms. _n1 and _n2 each independently represent an integer of 0 to 4.)

The method for synthesizing the copolymer contained in the composition of the present invention is not particularly limited, and it is synthesized by a polymerization method known in the art, for example, a melt polymerization method or a solution polymerization method using a corresponding dicarboxylic acid chloride. Among these, a solution polymerization method that allows polymerization under mild conditions is particularly preferred, and specifically, the compound of the present invention and at least one of a compound having structural unit B or a compound having structural unit C are subjected to interfacial polycondensation in a solvent.

Polymers that do not contain the structural unit A represented by formula (1) do not undergo photoreaction, and therefore thin films made of such polymers do not exhibit excellent liquid crystal alignment properties even when irradiated with polarized UV light or obliquely incident UV light and then subjected to heat treatment.

A polymer that does not contain the structural unit B represented by formula (2) and the structural unit C represented by formula (3) has low thermal alignment properties, and therefore a thin film made of the polymer does not exhibit excellent liquid crystal alignment properties even when irradiated with polarized UV light or oblique incidence UV light and subjected to heat treatment.

The composition of the present invention contains a thermal reorientation promoter. The molecular mobility of the optical thin film and retardation film obtained using the composition of the present invention is improved by the thermal reorientation promoter, making it possible to perform a thermal reorientation treatment of the polymer even on a general-purpose resin support substrate that has a low heat resistance temperature.

The thermal reorientation promoter contained in the composition of the present invention has a molecular weight of 200 or more and 10,000 or less. If the molecular weight is less than 200, problems occur such as precipitation and seepage of the additive in a high-temperature environment, or problems occur such as volatilization of the additive in a high-temperature environment, and the performance as an optical thin film cannot be maintained. If the molecular weight is more than 10,000, the efficiency of improving the molecular orientation of the polyester is poor. It is more preferable that the thermal reorientation promoter of the present invention has a molecular weight of 300 or more and 10,000 or less due to its low volatility during heat treatment.

The blend ratio of the polymer and the thermal reorientation promoter in the composition of the present invention is 80 to 99.99% by weight of the polymer and 0.01 to 20% by weight of the thermal reorientation promoter. In view of the problem of precipitation and exudation of the thermal reorientation promoter in a high-temperature environment, it is more preferable to use 85 to 99.9% by weight of the polymer and 0.1 to 15% by weight of the thermal reorientation promoter, and in terms of the efficiency of thermal reorientation promotion, it is particularly preferable to use 85 to 99.0% by weight of the polymer and 1.0 to 15% by weight of the thermal reorientation promoter. In the present invention, when the ratio of the thermal reorientation promoter is less than 0.01% by weight, it becomes difficult to promote thermal reorientation, and when it is more than 20% by weight, precipitation and exudation of the thermal reorientation promoter are likely to occur.

Examples of the thermal reorientation promoter of the present invention include plasticizers, antioxidants, and light stabilizers.

Plasticizers include carboxylate esters, phosphate esters, polymer plasticizers, etc.

Specific examples of carboxylate esters include phthalate esters, trimellitate esters, pyromellitate esters, citrate esters, oleate esters, ricinoleate esters, sebacate esters, stearates, adipates, and epoxy esters.

Specific examples of polymer-based plasticizers include polyester-based plasticizers and polyether-based plasticizers.

The thermal reorientation promoter of the present invention is preferably a plasticizer.

The phthalic acid esters that can be used as thermal reorientation promoters in the present invention refer to those having a molecular weight of 200 or more and 10,000 or less and containing the structure shown in the following formula (7).

(In formula (7), R ₁₉ and R ₂₀ each independently represent one selected from the group consisting of an alkyl group having 1 to 20 carbon atoms, an alicyclic hydrocarbon, an aromatic ring, a heterocycle, a polycyclic aromatic ring, or a condensed aromatic ring, which may have a substituent or an unsaturated bond. From the viewpoint of low volatility during heat treatment, it is preferable that R ₁₉ and R ₂₀ each independently have 2 or more carbon atoms.)

The trimellitic acid ester that can be used as a thermal reorientation promoter in the present invention refers to a compound having a molecular weight of 200 or more and 10,000 or less, which contains the structure shown in the following formula (8).

(In formula (8), R ₂₁ to R ₂₃ each independently represent one selected from the group consisting of an alkyl group having 1 to 20 carbon atoms, an alicyclic hydrocarbon, an aromatic ring, a heterocycle, a polycyclic aromatic ring, or a condensed aromatic ring, which may have a substituent or an unsaturated bond.)

The pyromellitic acid ester that can be used as a thermal reorientation promoter in the present invention refers to a compound having a molecular weight of 200 or more and 10,000 or less, which contains the structure shown in the following formula (9).

(In formula (9), R ₂₄ to R ₂₇ each independently represent one selected from the group consisting of an alkyl group having 1 to 20 carbon atoms, an alicyclic hydrocarbon, an aromatic ring, a heterocycle, a polycyclic aromatic ring, or a condensed aromatic ring, which may have a substituent or an unsaturated bond.)

The citrate esters that can be used as thermal reorientation promoters in the present invention refer to those having a molecular weight of 200 or more and 10,000 or less and containing the structure shown in the following formula (10).

(In formula (10), R ₂₈ to R ₃₀ each independently represent one selected from the group consisting of an alkyl group having 1 to 20 carbon atoms, an alicyclic hydrocarbon, an aromatic ring, a heterocycle, a polycyclic aromatic ring, or a fused aromatic ring, which may have either a substituent or an unsaturated bond. R ₃₁ represents one selected from the group consisting of a hydrogen atom, an acetyl group having 1 to 20 carbon atoms, an alkyl group having 1 to 20 carbon atoms, an alicyclic hydrocarbon, an aromatic ring, a heterocycle, a polycyclic aromatic ring, or a fused aromatic ring, which may have either a substituent or an unsaturated bond.)

The oleic acid esters that can be cited as thermal reorientation promoters in the present invention refer to those having a molecular weight of 200 or more and 10,000 or less, which contain the structure shown in the following formula (11).

(In formula (11), R ₃₂ represents one member selected from the group consisting of an alkyl group having 1 to 20 carbon atoms, an alicyclic hydrocarbon, an aromatic ring, a heterocycle, a polycyclic aromatic ring, or a condensed aromatic ring, which may have a substituent or an unsaturated bond.)

The ricinoleic acid esters that can be cited as thermal reorientation promoters in the present invention refer to those having a molecular weight of 200 or more and 10,000 or less, which contain the structure shown in the following formula (12).

(In formula (12), R ₃₃ represents one selected from the group consisting of an alkyl group having 1 to 20 carbon atoms, an alicyclic hydrocarbon, an aromatic ring, a heterocycle, a polycyclic aromatic ring, or a condensed aromatic ring, which may have either a substituent or an unsaturated bond. R ₃₄ represents one selected from the group consisting of a hydrogen atom, an acetyl group having 1 to 20 carbon atoms, an alkyl group having 1 to 20 carbon atoms, an alicyclic hydrocarbon, an aromatic ring, a heterocycle, a polycyclic aromatic ring, or a condensed aromatic ring, which may have either a substituent or an unsaturated bond.)

The sebacic acid esters that can be cited as thermal reorientation promoters in the present invention refer to those having a molecular weight of 200 or more and 10,000 or less and containing the structure shown in the following formula (13).

(In formula (13), R ₃₅ and R ₃₆ each independently represent one selected from the group consisting of an alkyl group having 1 to 20 carbon atoms, an alicyclic hydrocarbon, an aromatic ring, a heterocycle, a polycyclic aromatic ring, or a condensed aromatic ring, which may have a substituent or an unsaturated bond.)

The stearic acid esters that can be cited as thermal reorientation promoters in the present invention refer to those having a molecular weight of 200 or more and 10,000 or less, which contain the structure shown in the following formula (14).

(In formula (14), R ₃₇ represents one member selected from the group consisting of an alkyl group having 1 to 20 carbon atoms, an alicyclic hydrocarbon, an aromatic ring, a heterocycle, a polycyclic aromatic ring, or a condensed aromatic ring, which may have a substituent or an unsaturated bond.)

The adipic acid ester that can be cited as a thermal reorientation promoter of the present invention refers to an adipic acid ester having a molecular weight of 200 or more and 10,000 or less and containing the structure shown in the following formula (15).

(In formula (15), R ₃₈ and R ₃₉ each independently represent one selected from the group consisting of an alkyl group having 1 to 20 carbon atoms, an alicyclic hydrocarbon, an aromatic ring, a heterocycle, a polycyclic aromatic ring, or a condensed aromatic ring, which may have a substituent or an unsaturated bond. From the viewpoint of low volatility during heat treatment, it is preferable that R ₃₈ and R ₃₉ each independently represent a carbon number of 2 or more.)

The epoxidized esters that can be used as the thermal reorientation promoter of the present invention are not particularly limited as long as they have a molecular weight of 200 or more and have one or more epoxy groups and ester bonds. Examples include 4,5-epoxycyclohexane-1,2-dicarboxylate di-2-ethylhexyl, 4,5-epoxycyclohexane-1,2-dicarboxylate di-(9,10-epoxystearyl), epoxidized soybean oil, epoxidized linseed oil, epoxidized fatty acid isobutyl, epoxidized fatty acid 2-ethylhexyl, etc.

An example of a phosphate ester is a compound represented by the following formula (16):

(In formula (16), R ₄₀ to R ₄₂ each independently represent one selected from the group consisting of an alkyl group having 1 to 20 carbon atoms, an alicyclic hydrocarbon, an aromatic ring, a heterocycle, a polycyclic aromatic ring, or a condensed aromatic ring, which may have a substituent or an unsaturated bond. From the viewpoint of low volatility during heat treatment, it is preferable that R ₄₀ to R ₄₂ each independently have 3 or more carbon atoms.)

The polyester plasticizer that can be used as a thermal reorientation promoter in the present invention is a polymer that contains a structural unit represented by the following formula (17) and has a molecular weight of 200 or more and 10,000 or less.

(In formula (17), R ₄₃ and R ₄₄ each independently represent one selected from the group consisting of an alkyl group having 1 to 20 carbon atoms, an alicyclic hydrocarbon, an aromatic ring, a heterocycle, a polycyclic aromatic ring, or a condensed aromatic ring, which may have a substituent or an unsaturated bond.)

The polyether plasticizers that can be used as thermal reorientation promoters in the present invention are polymers that contain a structural unit represented by the following formula (18) and have a molecular weight of 200 or more and 10,000 or less.

In formula (18), R ₄₅ represents one member selected from the group consisting of an alkyl group having 1 to 20 carbon atoms, an alicyclic hydrocarbon, an aromatic ring, a heterocycle, a polycyclic aromatic ring, or a condensed aromatic ring, which may have a substituent or an unsaturated bond.

Examples of antioxidants include phenol-based antioxidants, amine-based antioxidants, phosphorus-based antioxidants, sulfur-based antioxidants, lactone-based antioxidants, hydroxylamine-based antioxidants, vitamin E-based antioxidants, and other antioxidants.

The thermal reorientation promoter of the present invention is preferably an antioxidant.

The phenol-based antioxidant that can be cited as a thermal reorientation promoter in the present invention refers to one that contains the structure shown in the following formula (19) and has a molecular weight of 200 to 10,000.

(In formula (19), at least one of R ₅₀ and R ₅₁ represents one selected from the group consisting of a secondary alkyl group having 2 to 20 carbon atoms, a tertiary alkyl group having 2 to 20 carbon atoms, a thioether group having 6 to 20 carbon atoms, an alicyclic hydrocarbon, an aromatic ring, a polycyclic aromatic ring, or a fused aromatic ring, which may have either a substituent or an unsaturated bond, and the other represents one selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a thioether group having 1 to 20 carbon atoms, an alicyclic hydrocarbon, an aromatic ring, a polycyclic aromatic ring, or a fused aromatic ring, which may have either a substituent or an unsaturated bond. These structures are not particularly limited, but a tert-butyl group is particularly preferred from the viewpoint of availability. R ₄₈ to R ₅₀ each independently represents one member selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alicyclic hydrocarbon, an aromatic ring, a heterocycle, a polycyclic aromatic ring, or a condensed aromatic ring, which may have a substituent or an unsaturated bond.

The phenol-based antioxidants that can be used as the thermal reorientation promoter of the present invention are not limited to those represented by formula (19), and examples include galvinoxyl free radical, 3,3',5,5'-tetra-tert-butyl-4,4'-stilbenequinone, 4-(hexyloxy)-2,3,6-trimethylphenol, etc.

The amine-based antioxidant that can be cited as a thermal reorientation promoter in the present invention refers to an antioxidant having a molecular weight of 200 or more and 10,000 or less, which contains the structure shown in the following formula (20).

(In formula (20), Ar ₃ represents a ring selected from the group consisting of an aromatic ring, a polycyclic aromatic ring, or a condensed aromatic ring, the ring of which is constituted by an atom selected from the group consisting of a carbon atom, a nitrogen atom, an oxygen atom, and a sulfur atom, and these aromatic rings, polycyclic aromatic rings, and condensed aromatic rings may have a substituent. R ₅₁ represents one selected from the group consisting of an alkyl group having 1 to 20 carbon atoms, an alicyclic hydrocarbon, an aromatic ring, a heterocycle, a polycyclic aromatic ring, or a condensed aromatic ring, which may have a substituent or an unsaturated bond. From the viewpoint of low volatility during heat treatment, it is preferable that R ₅₁ has 9 or more carbon atoms.)

The amine-based antioxidants that can be used as the thermal reorientation promoter of the present invention are not limited to those represented by formula (20), and examples include 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline, poly(2,2,4-trimethyl-1,2-dihydroquinoline), etc.

The phosphorus-based antioxidant that can be cited as a thermal reorientation promoter in the present invention refers to an antioxidant that contains the structure shown in the following formula (21) and has a molecular weight of 200 to 10,000.

(In formula (21), R ₅₂ and R ₅₃ each independently represent one selected from the group consisting of an alkyl group having 1 to 20 carbon atoms, an alicyclic hydrocarbon, an aromatic ring, a heterocycle, a polycyclic aromatic ring, or a condensed aromatic ring, which may have either a substituent or an unsaturated bond. R ₅₄ represents one selected from the group consisting of an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alicyclic hydrocarbon, an aromatic ring, a heterocycle, a polycyclic aromatic ring, or a condensed aromatic ring, which may have either a substituent or an unsaturated bond. From the viewpoint of low volatility during heat treatment, it is preferable that R ₅₂ , R ₅₃ , and R ₅₄ each independently have 3 or more carbon atoms.)

The sulfur-based antioxidant that can be cited as a thermal reorientation promoter in the present invention refers to one that contains the structure shown in the following formula (22) and has a molecular weight of 200 to 10,000.

(In formula (22), R ₅₅ represents one selected from the group consisting of an alkyl group having 1 to 20 carbon atoms, an alicyclic hydrocarbon, a heterocycle, an aromatic ring, a polycyclic aromatic ring, or a condensed aromatic ring, which may have either a substituent or an unsaturated bond. R ₅₆ represents one selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an alicyclic hydrocarbon, an aromatic ring, a heterocycle, a polycyclic aromatic ring, or a condensed aromatic ring, which may have either a substituent or an unsaturated bond. From the viewpoint of low volatility during heat treatment, it is preferable that R ₅₅ and R ₅₆ each independently have 6 or more carbon atoms.)

Examples of light stabilizers include hindered amine light stabilizers.

The thermal reorientation promoter of the present invention is preferably a light stabilizer.

The hindered amine-based light stabilizer that can be used as a thermal reorientation promoter in the present invention refers to a compound having a molecular weight of 200 or more and 10,000 or less and having a structural unit represented by the following formula (23).

(In formula (23), Y ₈ represents one member selected from the group consisting of -O-, -CO-, and -NR ₅₇ -. Here, R ₅₇ represents one member selected from the group consisting of a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. R ₅₈ to R ₆₁ each independently represent one member selected from the group consisting of an alkyl group having 1 to 20 carbon atoms, an alicyclic hydrocarbon, a heterocycle, an aromatic ring, a polycyclic aromatic ring, or a condensed aromatic ring, which may have a substituent or an unsaturated bond. Of these, a methyl group is particularly preferred from the viewpoint of availability. R ₆₂ represents one member selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alicyclic hydrocarbon atom, an aromatic ring, a heterocycle, a polycyclic aromatic ring, or a condensed aromatic ring, which may have a substituent or an unsaturated bond.)

Among these various additives, plasticizers are preferred because they are easily available, have good compatibility with resins, and have particularly excellent thermal reorientation promoting properties even after being added to resins. These thermal reorientation promoting agents may be used alone or in combination of two or more.

The thermal reorientation promoter of the present invention may be added for the purpose of improving thermal reorientation, as well as for the purpose of improving mechanical properties, imparting flexibility, imparting water absorption resistance, reducing water vapor transmission rate, improving thermal stability, improving weather resistance, etc.

The resin composition of the present invention may contain other polymers, surfactants, polymer electrolytes, conductive complexes, pigments, dyes, antistatic agents, antiblocking agents, lubricants, etc., within the scope of the invention.

The resin composition of the present invention can be obtained by blending a polyester resin having a photoreactive group and a thermal reorientation promoter (hereinafter referred to as resin, etc.).

Methods for blending include melt blending and solution blending. The melt blending method is a method of manufacturing by melting and kneading resins by heating. The solution blending method is a method of dissolving resins in a solvent and blending them. Examples of solvents that can be used for solution blending include halogen-based solvents such as 1,1,1,3,3,3-hexafluoroisopropanol, methylene chloride, and chloroform; aromatic solvents such as toluene and xylene; ketone-based solvents such as cyclopentanone, acetone, methyl ethyl ketone, and methyl isobutyl ketone; alcohol solvents such as methanol, ethanol, and propanol; ether solvents such as dioxane and tetrahydrofuran; dimethylformamide, N-methylpyrrolidone, and the like. It is also possible to blend resins after dissolving them in a solvent, or to knead powders, pellets, and the like of each resin and then dissolve them in a solvent. The obtained blended resin solution can be poured into a poor solvent to precipitate a resin composition, or the blended resin solution can be used as it is for manufacturing an optical film.

The composition of the present invention may contain other polymers, crystal nucleating agents, surfactants, polymer electrolytes, conductive complexes, inorganic fillers, pigments, antistatic agents, antiblocking agents, lubricants, etc., within the scope of the gist of the invention.

The composition of the present invention can be used in the form of a thin film. This allows it to exhibit optical properties and can be used as an optical thin film (hereinafter referred to as the "thin film of the present invention"). There are no particular limitations on the method for producing the thin film, and examples of the method include a melt film-forming method and a solution casting method.

(Melt film forming method)
Specific examples of the melt film forming method include melt extrusion using a T-die, calendar molding, heat pressing, coextrusion, co-melting, multi-layer extrusion, and inflation molding, and are not particularly limited.

(Solution casting method)
The solution casting method is a method in which a solution in which a composition is dissolved in a solvent (hereinafter referred to as a "casting dope") is cast onto a support substrate, and the solvent is then removed by heating or the like to obtain a thin film. In this case, methods for casting the casting dope onto the support substrate include spin coating, T-die, doctor blade, bar coater, roll coater, and lip coater. In particular, the most common method for industrial use is to continuously extrude the casting dope from a die onto a belt-shaped or drum-shaped support substrate. Examples of the support substrate that can be used include glass substrates, metal substrates such as stainless steel and ferrotype, and films such as polyethylene terephthalate, polyethylene naphthalate, cycloolefin polymer, and polyimide.

The optical thin film using the thin film of the present invention preferably has a thickness of 0.01 to 20 μm from the viewpoint of suitability for thinning optical components, and more preferably has a thickness of 1 to 20 μm from the viewpoint of film thickness yield.

(Surfactant)
The thin film of the present invention may contain at least one surfactant in order to reduce unevenness in the film thickness. Examples of the surfactant that can be contained include alkyl carboxylates, alkyl phosphates, alkyl sulfonates, fluoroalkyl carboxylates, fluoroalkyl phosphates, fluoroalkyl sulfonates, polyoxyethylene derivatives, fluoroalkyl ethylene oxide derivatives, polyethylene glycol derivatives, alkyl ammonium salts, and fluoroalkyl ammonium salts, and fluorine-containing surfactants are particularly preferred.

As mentioned above, the thin film of the present invention can be suitably used as an optical thin film, and since it exhibits phase difference in particular, it can be suitably used as a phase difference film.

The thin film of the present invention exhibits phase difference by irradiating ultraviolet light. The ultraviolet light may be polarized ultraviolet light or obliquely incident ultraviolet light. In this case, the wavelength of the ultraviolet light is preferably 200 nm or more and 400 nm or less, and from the viewpoint of lamp handling, it is particularly preferable that it is 248 nm or more and 365 nm or less. The amount of irradiation energy is preferably 10 mJ/cm ² or more and 10,000 mJ/cm ² or less, and from the viewpoint of productivity, it is particularly preferable that it is 10 mJ/cm ² or more and 5,000 mJ/cm ² or less.

After the ultraviolet irradiation, the thin film of the present invention is further heat-treated. This causes phase difference to appear. From the viewpoint of the heat resistance of the resin film support substrate, the heat treatment temperature is preferably 50°C or more and 200°C or less.

The thin film of the present invention can be used as a retardation film by irradiating it with polarized ultraviolet light or oblique incidence ultraviolet light and then subjecting it to a heat treatment to develop three-dimensional refractive index anisotropy.

The retardation properties of the optical thin film using the thin film of the present invention vary depending on the intended retardation film, and examples thereof include those in which the in-plane retardation (Re) calculated in 10 μm as shown in the following formula (A) is preferably 80 nm or more, more preferably 100 to 10,000 nm, and particularly preferably 100 to 5,000 nm. The retardation properties in this case are measured using a sample tilt type automatic birefringence meter (manufactured by AXOMETRICS, product name: AxoScan) under the condition of a measurement wavelength of 589 nm.
Re=(ny-nx)×d (A)
(In the formula, nx represents the refractive index in the in-plane fast axis direction, ny represents the refractive index in the in-plane slow axis direction, and d represents the thickness.)

The thin film of the present invention exhibits phase difference, and can therefore be used as a phase difference film. When used as a phase difference film, it may be used as a single film, or may be used as a multi-layer film in which other films are laminated. The film laminated on the thin film of the present invention may be the thin film of the present invention, or may be a polymerizable liquid crystal film, a sputtered film, or a resin film such as polyethylene terephthalate, polyethylene naphthalate, cycloolefin polymer, or polyimide.

The thin film of the present invention can be used as a liquid crystal alignment film because it aligns the liquid crystal compounds on the film.

The present invention will be described in more detail below with reference to examples, but the present invention should not be construed as being limited to these.

<Measurement of Nuclear Magnetic Resonance Spectrum>
¹ H-NMR spectrum was measured using a nuclear magnetic resonance spectrometer (manufactured by JEOL Ltd., trade name: ECZ 400S).

<Polarized UV irradiation>
Ultraviolet light was irradiated using a mercury light source (manufactured by Asahi Spectroscopy, product name: REX-250) equipped with a bandpass filter (248 nm). When irradiating polarized ultraviolet light, only P-polarized light was irradiated using a polarizing beam splitter of the corresponding wavelength.

<Heat Treatment>
The heat treatment was carried out using either an inert oven (manufactured by ESPEC, product name: IPHH-202) or a non-oxidizing atmosphere incubator.

<Measurement of Phase Difference Characteristics>
The retardation properties of the retardation film were measured using a sample tilt type automatic birefringence meter (manufactured by AXOMETRICS, product name: AxoScan) with light having a wavelength of 589 nm.

<Thin film thickness measurement>
The thickness of the thin film was measured using a spectroscopic ellipsometer (product name: RC2-U, manufactured by JA Woollam Co.).

<Polarizing microscope observation>
The low molecular weight liquid crystal on the thin film was observed using a microscope (Olympus, product name: BX53), a polarizing condenser (Olympus, product name: U-POC-2), and an analyzer (Olympus, product name: U-AN360P-2), and the liquid crystal orientation was observed.

<Synthesis Example 1>
According to the method described in Chinese Journal of Chemistry, 23, 1523, 2005, tetrahydropyranyl-coumaric acid (10 g, 40.3 mmmol) with a protected phenol moiety, trans-cyclohexanediol (2.29 g, 19.7 mmol), and 4-dimethylaminopyridine (2.5 g) as a base catalyst were dissolved in dehydrated dichloromethane (100 ml) at 0°C under a nitrogen stream. 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (8.49 g, 44.3 mmmol) was added thereto, and the mixture was allowed to react overnight after being returned to room temperature. Water was added to stop the reaction, and the solvent was distilled off under reduced pressure.
The residue was redissolved in tetrahydrofuran (200 ml), 2N hydrogen chloride (40 ml) was added, and the mixture was stirred at room temperature for two hours. The precipitate was filtered to obtain 6.74 g of compound 1. The results of the ¹ H-NMR spectrum are shown below.
¹ H-NMR (400 MHz, (CD ₃ ) ₂ SO): δ7.53-7.49 (m, 6H), 6.76-6.73 (m, 4H), 6.38-6.31 (m, 2H), 4.79 (brs, 2H), 1.94 (brs, 4H), 1.54 (brs, 4H).
(Compound 1)

<Synthesis Example 2>
Under a nitrogen stream, a mixture of 4-methoxy-N-methylaniline (3.00 g, 21.9 mmol), tetrahydrofuran (20 mL), and water (20 mL) was cooled on ice, and then sodium hydrogen carbonate (11 g) was added. While stirring the mixture, a solution of terephthalic acid chloride (2.17 g, 10.7 mmol) in tetrahydrofuran (20 mL) was slowly added, and the mixture was stirred for 3 hours under ice cooling. Water (500 mL) was added to the reaction mixture, and the resulting solid was collected by filtration and washed with 2N hydrochloric acid (200 mL) and methanol (300 mL) to obtain N,N'-bis(4-methoxyphenyl)-N,N'-dimethyl-1,4-benzenedicarboxamide (3.91 g, yield: 90%). The results of the ¹ H-NMR spectrum are shown below.
¹ H-NMR (400 MHz, (CD ₃ ) ₂ SO): δ7.07 (s, 4H), 6.83 (d, J=8.0 Hz, 4H), 6.67 (d, J=8.0 Hz, 4H), 3.73 (s, 6H), 3.38 (s, 6H).
The N,N'-bis(4-methoxyphenyl)-N,N'-dimethyl-1,4-benzenedicarboxamide (1.00 g, 2.47 mmol) obtained above was dissolved in dichloromethane (25 mL), and then 1 mol/L boron tribromide dichloromethane solution (7.4 mL) was added over 5 minutes under ice-cooling. The reaction system was warmed to room temperature, stirred for 15 hours, and the reaction mixture was added to ice-cooled water (300 mL). The solid generated in the system was filtered and washed with water (500 mL) to obtain a brown solid of compound 2 (776 mg, 83%). The results of the ¹ H-NMR spectrum are shown below.
¹ H-NMR (400 MHz, (CD ₃ ) ₂ SO): δ9.55-9.28 (br, 2H), 6.98 (s, 4H), 6.87-6.67 (m, 4H), 6.58-6.49 (m, 4H), 3.20 (s, 6H).
(Compound 2)

<Synthesis Example 3>
In a three-neck flask equipped with a dropping funnel, ion-exchanged water (18.5 mL) was taken, and compound 1 (0.160 g, 0.392 mmol), compound 2 (1.24 g, 3.29 mmol), and sodium hydroxide (0.300 g, 7.50 mmol) were dissolved and stirred. A 2.0 wt% aqueous solution (1.5 mL) of tetra-n-butylammonium bromide was added as a catalyst, and the inside of the apparatus was replaced with nitrogen. A solution of compound 3 (0.773 g, 3.70 mmol) dissolved in chloroform (18.5 mL) was taken in a dropping funnel, dropped, and then stirred at room temperature for three hours. The solution after the reaction was poured into methanol, and the precipitate was filtered off, and then vacuum dried to obtain polymer 1 (yield 88%).
(Compound 3)

[Example 1]
4.5% by weight of polymer 1 and 0.5% by weight of dibutyl phthalate (molecular weight: 278) as a thermal reorientation promoter were dissolved in 95% by weight of 1,1,1,3,3,3-hexafluoroisopropanol. This was cast onto a quartz glass substrate, spin-coated at 6000 rpm for 60 seconds, and dried in an oven at 60°C for 60 minutes to obtain a thin film (film thickness 0.847 μm). The obtained thin film was irradiated with 500 mJ/ ^cm2 of polarized ultraviolet light of 248 nm and then heated at 150°C, whereupon a high phase difference was exhibited. The phase difference amount converted to a film thickness of 10 μm is shown in Table 1.

[Example 2]
5.0% by weight of polymer 1 and 0.56% by weight of ditridecyl phthalate (molecular weight: 531) as a thermal reorientation promoter were dissolved in 94.44% by weight of 1,1,1,3,3,3-hexafluoroisopropanol. This was cast onto a quartz glass substrate, spin-coated at 6000 rpm for 60 seconds, and dried in an oven at 60°C for 60 minutes to obtain a thin film (film thickness 0.941 μm). The obtained thin film was irradiated with 500 mJ/ ^cm2 of polarized ultraviolet light of 248 nm and then heated at 140°C, whereupon a high phase difference was expressed. The phase difference amount converted to a film thickness of 10 μm is shown in Table 1.

[Example 3]
A thin film (film thickness 0.916 μm) was obtained in the same manner as in Example 2, except that bis(2-ethylhexyl) isophthalate (molecular weight: 391) was used as the thermal reorientation promoter. The obtained thin film was irradiated with 500 mJ/ ^cm2 of polarized ultraviolet light of 248 nm and then heated at 140° C., whereby a high retardation was exhibited. The retardation amount converted into a film thickness of 10 μm is shown in Table 1.

[Example 4]
A thin film (film thickness 0.714 μm) was obtained in the same manner as in Example 1, except that tributyl trimellitate (molecular weight: 378) was used as the thermal reorientation promoter. The obtained thin film was irradiated with 248 nm polarized ultraviolet light at 500 mJ/ ^cm2 and then heated at 150°C, whereupon a high retardation was exhibited. The retardation amount converted into a film thickness of 10 μm is shown in Table 1.

[Example 5]
A thin film (film thickness 0.955 μm) was obtained in the same manner as in Example 2, except that tris(2-ethylhexyl) trimellitate (molecular weight: 547) was used as the thermal reorientation promoter. The obtained thin film was irradiated with 500 mJ/ ^cm2 of polarized ultraviolet light of 248 nm and then heated at 140° C., whereby a high retardation was exhibited. The retardation amount converted into a film thickness of 10 μm is shown in Table 1.

[Example 6]
A thin film (film thickness 0.851 μm) was obtained in the same manner as in Example 1, except that triethyl citrate (molecular weight: 276) was used as a thermal reorientation promoter. The obtained thin film was irradiated with 248 nm polarized ultraviolet light at 500 mJ/ ^cm2 and then heated at 150° C., whereupon a high retardation was exhibited. The retardation amount converted into a film thickness of 10 μm is shown in Table 1.

[Example 7]
A thin film (film thickness 0.879 μm) was obtained in the same manner as in Example 2, except that trihexyl O-butyrylcitrate (molecular weight: 514) was used as the thermal reorientation promoter. The obtained thin film was irradiated with 500 mJ/ ^cm2 of polarized ultraviolet light of 248 nm and then heated at 140° C., whereby a high retardation was exhibited. The retardation amount converted into a film thickness of 10 μm is shown in Table 1.

[Example 8]
A thin film (film thickness 0.881 μm) was obtained in the same manner as in Example 1, except that tributyl phosphate (molecular weight: 266) was used as a thermal reorientation promoter and spin-coated at 4000 rpm. The obtained thin film was irradiated with 248 nm polarized ultraviolet light at 500 mJ/ ^cm2 and then heated at 140°C, whereupon a high phase difference was exhibited. The phase difference amount converted to a film thickness of 10 μm is shown in Table 1.

[Example 9]
A thin film (film thickness 0.867 μm) was obtained in the same manner as in Example 1, except that tris(2-chloroethyl)phosphate (molecular weight: 285) was used as a thermal reorientation promoter and spin-coated at 4000 rpm. When the obtained thin film was irradiated with 500 mJ/ ^cm2 of polarized ultraviolet light of 248 nm and then heated at 140°C, a high retardation was exhibited. The retardation amount converted into a film thickness of 10 μm is shown in Table 1.

[Example 10]
A thin film (film thickness 0.902 μm) was obtained in the same manner as in Example 1, except that triamyl phosphate (molecular weight: 308) was used as a thermal reorientation promoter and spin-coated at 4000 rpm. The obtained thin film was irradiated with 248 nm polarized ultraviolet light at 500 mJ/ ^cm2 and then heated at 140°C, whereupon a high phase difference was exhibited. The phase difference amount converted to a film thickness of 10 μm is shown in Table 1.

[Example 11]
A thin film (film thickness 0.899 μm) was obtained in the same manner as in Example 1, except that triphenyl phosphate (molecular weight: 326) was used as a thermal reorientation promoter and spin-coated at 4000 rpm. The obtained thin film was irradiated with 248 nm polarized ultraviolet light at 500 mJ/ ^cm2 and then heated at 140°C, whereupon a high phase difference was exhibited. The phase difference amount converted to a film thickness of 10 μm is shown in Table 1.

[Example 12]
A thin film (film thickness 0.945 μm) was obtained in the same manner as in Example 1, except that 2-ethylhexyl diphenyl phosphate (molecular weight: 362) was used as a thermal reorientation promoter and spin-coated at 4000 rpm. When the obtained thin film was irradiated with 500 mJ/ ^cm2 of polarized ultraviolet light of 248 nm and then heated at 140°C, a high retardation was exhibited. The retardation amount converted into a film thickness of 10 μm is shown in Table 1.

[Example 13]
A thin film (film thickness 0.879 μm) was obtained in the same manner as in Example 1, except that tri-o-cresyl phosphate (molecular weight: 368) was used as a thermal reorientation promoter and spin-coated at 4000 rpm. When the obtained thin film was irradiated with 500 mJ/ ^cm2 of 248 nm polarized ultraviolet light and then heated at 140°C, a high retardation was exhibited. The retardation amount converted into a film thickness of 10 μm is shown in Table 1.

[Example 14]
4.95% by weight of polymer 1 and 0.05% by weight of tricresyl phosphate (molecular weight: 368) as a thermal reorientation promoting plasticizer were dissolved in 95% by weight of 1,1,1,3,3,3-hexafluoroisopropanol. This was cast onto a quartz glass substrate, spin-coated at 4000 rpm for 60 seconds, and dried in an oven at 60°C for 60 minutes to obtain a thin film (film thickness 1.022 μm). The obtained thin film was irradiated with 500 mJ/ ^cm2 of polarized ultraviolet light of 248 nm and then heated at 140°C, whereupon a high phase difference was exhibited. The phase difference amount converted to a film thickness of 10 μm is shown in Table 1.

[Example 15]
A thin film (film thickness 0.911 μm) was obtained in the same manner as in Example 2, except that tricresyl phosphate (molecular weight: 368) was used as a thermal reorientation promoting plasticizer and spin-coated at 6000 rpm. The obtained thin film was irradiated with 248 nm polarized ultraviolet light at 500 mJ/ ^cm2 and then heated at 140°C, whereupon a high retardation was exhibited. The retardation amount converted to a film thickness of 10 μm is shown in Table 1.

[Example 16]
4% by weight of polymer 1 and 1% by weight of tricresyl phosphate (molecular weight: 368) as a thermal reorientation promoting plasticizer were dissolved in 95% by weight of 1,1,1,3,3,3-hexafluoroisopropanol. This was cast onto a quartz glass substrate, spin-coated at 5000 rpm for 60 seconds, and dried in an oven at 60°C for 60 minutes to obtain a thin film (film thickness 0.752 μm). The obtained thin film was irradiated with 500 mJ/ ^cm2 of polarized ultraviolet light of 248 nm and then heated at 140°C, whereupon a high phase difference was exhibited. The phase difference amount converted to a film thickness of 10 μm is shown in Table 1.

[Example 17]
A thin film (film thickness 0.881 μm) was obtained in the same manner as in Example 1, except that tris(2-butoxyethyl)phosphate (molecular weight: 398) was used as a thermal reorientation promoting plasticizer and spin-coated at 4000 rpm. When the obtained thin film was irradiated with 248 nm polarized ultraviolet light at 500 mJ/ ^cm2 and then heated at 140°C, a high retardation was exhibited. The retardation amount converted into a film thickness of 10 μm is shown in Table 1.

[Example 18]
A thin film (film thickness 0.901 μm) was obtained in the same manner as in Example 1, except that tris(1,3-dichloro-2-propyl)phosphate (molecular weight: 431) was used as a thermal reorientation promoting plasticizer and spin-coated at 4000 rpm. When the obtained thin film was irradiated with 500 mJ/ ^cm2 of polarized ultraviolet light of 248 nm and then heated at 140°C, a high retardation was exhibited. The retardation amount converted into a film thickness of 10 μm is shown in Table 1.

[Example 19]
A thin film (film thickness 0.967 μm) was obtained in the same manner as in Example 1, except that tris(2-ethylhexyl) phosphate (molecular weight: 435) was used as a thermal reorientation promoting plasticizer and spin-coated at 4000 rpm. When the obtained thin film was irradiated with 500 mJ/ ^cm2 of polarized ultraviolet light of 248 nm and then heated at 140° C., a high retardation was exhibited. The retardation amount converted into a film thickness of 10 μm is shown in Table 1.

[Example 20]
A thin film (film thickness 0.945 μm) was obtained in the same manner as in Example 2, except that dioctyl 4-cyclohexene-1,2-dicarboxylate (molecular weight: 451) was used as the thermal reorientation promoting plasticizer. When the obtained thin film was irradiated with 500 mJ/ ^cm2 of polarized ultraviolet light of 248 nm and then heated at 140° C., a high retardation was exhibited. The retardation amount converted into a film thickness of 10 μm is shown in Table 1.

[Example 21]
A thin film (film thickness 1.113 μm) was obtained in the same manner as in Example 1, except that Adeka Cizer P-300 (molecular weight: 3000, adipic acid polyester) was used as a thermal reorientation promoting plasticizer and spin-coated at 2000 rpm. When the obtained thin film was irradiated with 248 nm polarized ultraviolet light at 500 mJ/ ^cm2 and then heated at 140°C, a high phase difference was exhibited. The phase difference amount converted into a film thickness of 10 μm is shown in Table 1.

[Example 22]
A thin film (film thickness 0.952 μm) was obtained in the same manner as in Example 14, except that Irganox (registered trademark) 245 (bis[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionic acid][ethylenebis(oxyethylene)]) (molecular weight: 587) was used as the thermal reorientation promoting plasticizer. The obtained thin film was irradiated with 248 nm polarized ultraviolet light at 500 mJ/ ^cm2 and then heated at 140°C, whereupon a high retardation was exhibited. The retardation amount converted into a film thickness of 10 μm is shown in Table 1.

[Example 23]
A thin film (film thickness 0.915 μm) was obtained in the same manner as in Example 1, except that Irganox (registered trademark) 245 (bis[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionic acid][ethylenebis(oxyethylene)]) (molecular weight: 587) was used as a thermal reorientation promoting plasticizer and spin-coated at 4000 rpm. The obtained thin film was irradiated with 248 nm polarized ultraviolet light at 500 mJ/ ^cm2 and then heated at 140°C, whereupon a high retardation was exhibited. The retardation amount converted into a film thickness of 10 μm is shown in Table 1.

[Example 24]
4.25% by weight of polymer 1 and 0.75% by weight of Irganox (registered trademark) 245 (bis [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionic acid] [ethylene bis (oxyethylene)]) (molecular weight: 587) as a thermal reorientation promoting plasticizer were dissolved in 95% by weight of 1,1,1,3,3,3-hexafluoroisopropanol. This was cast onto a quartz glass substrate, spin-coated at 4000 rpm for 60 seconds, and dried in an oven at 60 ° C. for 60 minutes to obtain a thin film (film thickness 0.936 μm). The obtained thin film was irradiated with 500 mJ / cm ² of polarized ultraviolet light of 248 nm and then heated at 140 ° C., whereupon a high phase difference was expressed. The phase difference amount converted to a film thickness of 10 μm is shown in Table 1.

[Example 25]
A thin film (film thickness 1.337 μm) was obtained in the same manner as in Example 1, except that 4.5% by weight of polymer 1 and 0.5% by weight of 4,4'-bis(α,α-dimethylbenzyl)diphenylamine (molecular weight: 406) as a thermal reorientation promoting plasticizer were dissolved in a 95% by weight solution of 1,1,1,3,3,3-hexafluoroisopropanol/chloroform = 4/1 (weight ratio) and spin-coated at 2000 rpm. When the obtained thin film was irradiated with 500 mJ/cm ² of polarized ultraviolet light of 248 nm and then heated at 140 ° C., a high retardation was exhibited. The retardation amount converted to a film thickness of 10 μm is shown in Table 1.

[Example 26]
A thin film (film thickness 1.127 μm) was obtained in the same manner as in Example 1, except that isodecyl phosphite (molecular weight: 503) was used as a thermal reorientation promoting plasticizer and spin-coated at 2000 rpm. The obtained thin film was irradiated with 248 nm polarized ultraviolet light at 500 mJ/ ^cm2 and then heated at 140°C, whereupon a high phase difference was exhibited. The phase difference amount converted to a film thickness of 10 μm is shown in Table 1.

[Example 27]
A thin film (film thickness 1.054 μm) was obtained in the same manner as in Example 1, except that 3,3'-thiodipropionate didodecyl (molecular weight: 515) was used as a thermal reorientation promoting plasticizer and spin-coated at 2000 rpm. When the obtained thin film was irradiated with 248 nm polarized ultraviolet light at 500 mJ/ ^cm2 and then heated at 140°C, a high retardation was exhibited. The retardation amount converted to a film thickness of 10 μm is shown in Table 1.

[Example 28]
A thin film (film thickness 0.963 μm) was obtained in the same manner as in Example 14, except that bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate (molecular weight: 509) was used as the thermal reorientation promoting plasticizer. When the obtained thin film was irradiated with 248 nm polarized ultraviolet light at 500 mJ/ ^cm2 and then heated at 140°C, a high retardation was exhibited. The retardation amount converted into a film thickness of 10 μm is shown in Table 1.

[Example 29]
A thin film (film thickness 0.937 μm) was obtained in the same manner as in Example 1, except that bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate (molecular weight: 509) was used as a thermal reorientation promoting plasticizer and spin-coated at 4000 rpm. When the obtained thin film was irradiated with 248 nm polarized ultraviolet light at 500 mJ/ ^cm2 and then heated at 140°C, a high retardation was exhibited. The retardation amount converted into a film thickness of 10 μm is shown in Table 1.

[Example 30]
A thin film (film thickness 1.009 μm) was obtained in the same manner as in Example 24, except that bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate (molecular weight: 509) was used as a thermal reorientation promoting plasticizer and spin-coated at 4000 rpm. When the obtained thin film was irradiated with 248 nm polarized ultraviolet light at 500 mJ/ ^cm2 and then heated at 140°C, a high retardation was exhibited. The retardation amount converted into a film thickness of 10 μm is shown in Table 1.

[Example 31]
1.8% by weight of polymer 1 and 0.2% by weight of tricresyl phosphate (molecular weight: 368) as a thermal realignment promoter were dissolved in 98% by weight of 1,1,1,3,3,3-hexafluoroisopropanol. This was cast onto a quartz glass substrate, spin-coated at 6000 rpm for 60 seconds, and dried in an oven at 60°C for 60 minutes to obtain a thin film (film thickness 0.2 μm). The obtained thin film was irradiated with 248 nm polarized ultraviolet light at 500 mJ/ ^cm2 , and then heated at 130°C to form a liquid crystal alignment film.
Using two 25 μm thick PET films (manufactured by Toray, product name: Lumirror (R) T60) cut to 1.5 mm x 20 mm as spacers, two quartz glass plates on which the liquid crystal alignment film was laminated were stacked so that the thin film was on the inside and the direction of irradiation with polarized ultraviolet light was parallel, and the periphery of the quartz glass plates, except for the part that would become the liquid crystal injection port area, was bonded with instant adhesive (manufactured by Toagosei, Aron Alpha 201) to form an empty liquid crystal cell. After bonding, 4-cyano-4'-pentylbiphenyl heated at 50°C was injected into the empty liquid crystal cell to form a liquid crystal cell. The obtained liquid crystal cell was observed using a polarizing microscope in three directions, with the polarizer angle at 0°, 45°, and 90° relative to the direction in which the thin film was irradiated with polarized ultraviolet light. The microscope image changed from dark to light to dark, and it was confirmed that the liquid crystal director was uniformly aligned and oriented. Table 2 shows whether or not a liquid crystal alignment film can be produced by heat treatment at 200°C or less.
[In this specification, the liquid crystal director refers to a vector in the direction in which the major axes of liquid crystal molecules are aligned (main alignment axis).]

[Comparative Example 1]
5% by weight of polymer 1 was dissolved in 95% by weight of 1,1,1,3,3,3-hexafluoroisopropanol. This was cast onto a quartz glass substrate, spin-coated at 6000 rpm for 60 seconds, and dried in an oven at 60°C for 60 minutes to obtain a thin film (film thickness 0.954 µm). The obtained thin film was irradiated with 500 mJ/ ^cm2 of polarized ultraviolet light of 248 nm and then heated at 140°C, but no high retardation was observed. The retardation amount converted into a film thickness of 10 µm is shown in Table 1.

[Comparative Example 2]
4.5% by weight of polymer 1 and 0.5% by weight of dimethyl phthalate (molecular weight: 194) were dissolved in 95% by weight of 1,1,1,3,3,3-hexafluoroisopropanol. This was cast onto a quartz glass substrate, spin-coated at 6000 rpm for 60 seconds, and dried in an oven at 60°C for 60 minutes to obtain a thin film (film thickness 0.856 μm). The obtained thin film was irradiated with 248 nm polarized ultraviolet light at 500 mJ/ ^cm2 and then heated at 150°C, but no high retardation was observed. The retardation amount converted to a film thickness of 10 μm is shown in Table 1.

[Comparative Example 3]
4.5% by weight of polymer 1 and 0.5% by weight of trimethyl phosphate (molecular weight: 140) were dissolved in 95% by weight of 1,1,1,3,3,3-hexafluoroisopropanol. This was cast onto a quartz glass substrate, spin-coated at 4000 rpm for 60 seconds, and dried in an oven at 60°C for 60 minutes to obtain a thin film (film thickness 0.867 μm). The obtained thin film was irradiated with 248 nm polarized ultraviolet light at 500 mJ/ ^cm2 and then heated at 150°C, but no high retardation was observed. The retardation amount converted to a film thickness of 10 μm is shown in Table 1.

[Comparative Example 4]
2% by weight of polymer 1 was dissolved in 98% by weight of 1,1,1,3,3,3-hexafluoroisopropanol. This was cast onto a quartz glass substrate, spin-coated at 7000 rpm for 60 seconds, and dried in an oven at 60°C for 60 minutes to obtain a thin film (film thickness 0.2 μm). The obtained thin film was irradiated with 248 nm polarized ultraviolet light at 500 mJ/ ^cm2 , and then heated at 130°C to obtain a thin film.
Using two 25 μm thick PET films (manufactured by Toray, product name: Lumirror (R) T60) cut to 1.5 mm x 20 mm as spacers, two quartz glass plates on which the thin film was laminated were stacked so that the thin film was on the inside and the direction of irradiation with polarized ultraviolet light was parallel, and the periphery of the quartz glass plates, except for the part that would become the liquid crystal injection port area, was bonded with instant adhesive (manufactured by Toagosei, Aron Alpha 201) to prepare an empty liquid crystal cell. After bonding, 4-cyano-4'-pentylbiphenyl heated at 50°C was injected into the empty liquid crystal cell to prepare a liquid crystal cell. The obtained liquid crystal cell was observed in three directions using a polarizing microscope, with the polarizer angle at 0°, 45°, and 90° relative to the direction in which the thin film was irradiated with polarized ultraviolet light. The microscope image was always bright, and it was confirmed that the liquid crystal director was not uniformly aligned and oriented. Table 2 shows whether or not a liquid crystal alignment film can be produced by heat treatment at 200°C or less.

The fact that the thin film of Example 31 can be used as a liquid crystal alignment film by irradiating it with polarized ultraviolet light and subjecting it to a heat treatment at 200°C or less becomes even more evident when compared with Comparative Example 4.

Claims (12)

A resin composition containing 80 to 99.99% by weight of a polymer having a structural unit A represented by the following formula (1), a structural unit B represented by the following formula (2) , and a structural unit C represented by the following formula (3), and 0.01 to 20% by weight of a thermal reorientation promoter having a molecular weight of 200 or more and 10,000 or less.
(In formula (1), X ₁ to X ₃ each independently represent an alicyclic hydrocarbon group having 5 to 7 carbon atoms which may have a substituent , and any carbon atom in the alicyclic hydrocarbon group may be substituted with a nitrogen atom, an oxygen atom or a sulfur atom. Here, the substituents in X ₁ to X ₃ each independently represent one type of the group consisting of a halogen atom, an alkyl group having 1 to 5 carbon atoms, and an alkoxy group having 1 to 5 carbon atoms, and when X ₁ to X ₃ do not have a substituent, it is a hydrogen atom. Y ₁ and Y ₂ represent -O- . _{Ar 1} and Ar ₂ each independently represent an aromatic ring having 5 to 7 carbon atoms which may have a substituent, and any carbon atom in the aromatic ring may be substituted with a nitrogen atom, an oxygen atom or a sulfur atom. Here, the substituents in Ar ₁ and Ar ₂ each independently represent one type of the group consisting of a halogen atom, an alkyl group having 1 to 5 carbon atoms, and an alkoxy group having 1 to 5 carbon atoms, and when Ar ₁ and Ar When ₂ has no substituent, it is a hydrogen atom.
R ₁ to R ₄ each represent a hydrogen atom . _{L 1} and L ₄ each represent --O-- . _{L 2} and L ₃ each represent a single bond .
a and b represent 0 .
(In formula (2), _Y3 and _Y4 represent -O- . _X4 to _X6 each independently represent an aromatic ring having 5 to 7 carbon atoms which may have a substituent , and any carbon atom in the aromatic ring may be substituted with a nitrogen atom, an oxygen atom or a sulfur atom. _R11 and _R12 represent an alkyl group having 1 to 5 carbon atoms . c represents 0 or 1.)
(In formula (3), _Y5 and _Y6 represent —CO— . Z represents an alicyclic hydrocarbon group having 5 to 7 carbon atoms .) The resin composition according to claim 1 , wherein Ar ₁ and Ar ₂ in formula (1) are benzene rings which may have a substituent. The resin composition according to any one of claims 1 to 2 , wherein the thermal reorientation promoter is a plasticizer. 3. The resin composition according to claim 1 , wherein the thermal reorientation promoter is an antioxidant. 3. The resin composition according to claim 1 , wherein the thermal reorientation promoter is a light stabilizer. An optical thin film comprising the resin composition according to any one of claims 1 to 5 . An optical thin film obtained by irradiating the optical thin film according to claim 6 with ultraviolet light. An optical thin film obtained by irradiating the optical thin film according to claim 7 with polarized ultraviolet light or obliquely incident ultraviolet light. 9. The optical thin film according to claim 7 , wherein the photoreaction rate of the photoreactive group is 50% or less. 10. An optical thin film, which is obtained by heating the optical thin film according to any one of claims 7 to 9 at a temperature within a range in which the resin composition exhibits liquid crystallinity. A retardation film comprising the thin film according to any one of claims 6 to 10 . A liquid crystal alignment film comprising the thin film according to any one of claims 6 to 10 .