Phase difference film composition and single-layer phase difference material

Abstract

This phase difference film composition contains: (A) a polymer in which throughout the polymer, there is at least one combination that has two or more types of side chains (a) having a photoreactive site represented by formula (a) or that has one or more types of side chains (a) and one or more types of side chains (b) not having a photoreactive site represented by formula (b), the minimum numbers of atoms (ACmin) of the respective side chains being different from each other; and (B) a solvent. The phase difference film composition makes it possible to produce a single-layer phase difference material with little turbidity by a simpler process. (In the formulas, the definition of each substituent is as described in the description.)

Description

Composition for retardation film and single-layer retardation material

[0001] The present invention relates to a polymer-containing composition for retardation films and a single-layer retardation material. More specifically, the present invention relates to a material having optical properties suitable for applications such as display devices and recording materials, particularly to a composition containing a liquid crystal polymer suitable for optical compensation films such as polarizing plates and retardation plates for liquid crystal displays and organic EL (Electro Luminescence) display devices, and a single-layer retardation material obtained from the composition.

[0002] Due to demands for improved display quality and weight reduction of liquid crystal display devices, there is an increasing demand for polymer films with controlled internal molecular orientation structures as optical compensation films such as polarizing plates and retardation plates. To meet this demand, films utilizing the optical anisotropy of polymerizable liquid crystal compounds have been developed. The polymerizable liquid crystal compounds used here are generally liquid crystal compounds having a polymerizable group and a liquid crystal structural moiety (a structural moiety having a spacer portion and a mesogen portion), and an acrylic group is widely used as the polymerizable group.

[0003] Such polymerizable liquid crystal compounds are generally made into polymers (films) by a method of polymerizing them by irradiating them with radiation such as ultraviolet light. For example, a method is known in which a specific polymerizable liquid crystal compound having an acrylic group is supported between supports, and this compound is irradiated with radiation while being maintained in a liquid crystal state to obtain a polymer (Patent Document 1), and a method is known in which a photopolymerization initiator is added to a mixture of two types of polymerizable liquid crystal compounds having an acrylic group or a composition obtained by mixing this mixture with a chiral liquid crystal, and then irradiating the mixture with ultraviolet light to obtain a polymer (Patent Document 2).

[0004] In addition, various single-layer coating-type alignment films have been reported, such as alignment films using polymerizable liquid crystal compounds or polymers that do not require a liquid crystal alignment film (Patent Documents 3 and 4), and alignment films using polymers containing photocrosslinking moieties (Patent Documents 5 and 6). Polymers that exhibit high alignment tend to aggregate due to strong interactions, which causes the problem of haze (turbidity) when used as a retardation material. No material that solves this problem has been found to date.

[0005] JP-A-62-70407 JP-A-9-208957 EP-A-1090325 WO 2008 / 031243 JP-A-2008-164925 JP-A-11-189665

[0006] The present invention has been made in consideration of the above problems, and aims to provide a polymer composition that enables the production of a single-layer retardation material with less turbidity by a simpler process, and a single-layer retardation material obtained from the polymer composition.

[0007] As a result of extensive research to solve the above problems, the inventors discovered that by using a composition containing a specific polymer and a specific additive, it is possible to prepare a single-layer retardation material having low turbidity and anisotropy (Δn) without using a liquid crystal alignment film, and thus completed the present invention.

[0008] Therefore, the present invention provides the following retardation film composition and single-layer retardation material: [1] (A) A retardation film composition and a single-layer retardation material, each of which has two or more types of side chains (a) having a photoreactive moiety represented by the following formula (a), or which has one or more types of the side chains (a) and one or more types of side chains (b) having no photoreactive moiety represented by the following formula (b), and the shortest number of atoms between the side chains (AC min ) is present throughout the polymer; and (B) a solvent. (In formula (a), n1 is 0, 1, 2 or 3. L A is a single bond or a linear alkylene group having 1 to 30 carbon atoms, and one or more hydrogen atoms of the alkylene group may be substituted with a fluorine atom or a monovalent organic group. A In the formula, -CH2- is -O-, -NR L -, -C(=O)-, -C(=O)-O-, -O-C(=O)-, -C(=O)-NR L -, -NR L -C(=O)-, -NR L —C(═O)—NR L -, -CH=CH-, an alicyclic group, and an aromatic group (where R Leach independently represents a hydrogen atom or a monovalent organic group.) However, adjacent -CH2- groups cannot be substituted with these groups at the same time. Q 1 is an aromatic group, a polycyclic aromatic group, an alicyclic group, a phenylenecyclohexylene group, a heterocyclic group, or a fused ring group. 1 When the number of is 2 or more, each Q 1 may be the same or different. 1 represents a single bond, -CH2-, -O-, -C(=O)-, -N=N-, -CH=CH-, -C≡C-, -NR X -, -C(=O)-O-, -OC(=O)-, -CH=CH-C(=O)-O-, -OC(=O)-CH=CH-, -C(=O)-NR X -, -NR X —C(═O)— or —NR X —C(═O)—NR X - (However, R X Each of X independently represents a hydrogen atom or a monovalent organic group. 1 When the number of is 2 or more, each X 1 may be the same or different. Align is a group having a photoreactive site. A hydrogen atom in the ring structure in formula (a) may be substituted with a substituent selected from an alkyl group having 1 to 6 carbon atoms, an alkylcarbonyl group having 2 to 6 carbon atoms, a haloalkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a haloalkoxy group having 1 to 6 carbon atoms, a halogen atom, a cyano group, and a nitro group. The dashed line represents a bond to the polymerizable group. However, L A In this, Q 1 At the end of the side, -Q 1 -X 1 - * (* is Q 1 It does not have a structure represented by (In formula (b), L B is a single bond or a linear alkylene group having 1 to 30 carbon atoms, and one or more hydrogen atoms of the alkylene group may be substituted with a fluorine atom or a monovalent organic group. B In the formula, -CH2- is -O-, -NR L-, -C(=O)-, -C(=O)-O-, -O-C(=O)-, -C(=O)-NR L -, -NR L -C(=O)-, -NR L —C(═O)—NR L -, -CH=CH-, an alicyclic group, and an aromatic group (where R L each independently represents a hydrogen atom or a monovalent organic group. B is an aromatic group, a polycyclic aromatic group, an alicyclic group, a phenylenecyclohexylene group, a heterocyclic group, or a fused ring group. B When the number of is 2 or more, each Q B may be the same or different. B represents a single bond, —CH—, —O—, —C(═O)—, or —NR X -, -C(=O)-O-, -OC(=O)-, -C(=O)-NR X -, -NR X —C(═O)— or —NR X —C(═O)—NR X - (However, R X Each of X independently represents a hydrogen atom or a monovalent organic group. B When the number of is 2 or more, each X B may be the same or different. B is an alkylene group having 1 to 10 carbon atoms, and one or more hydrogen atoms of the alkylene group may be substituted with a fluorine atom or an organic group. B In the formula, -CH2- is -O-, -NR R - (However, R R represents a hydrogen atom or a monovalent organic group. ) and —C(═O)— may be substituted. Adjacent —CH2— may simultaneously be substituted with these groups. R Crepresents a hydrogen atom or a monovalent organic group. The hydrogen atom in the ring structure in formula (b) may be substituted with a substituent selected from an alkyl group having 1 to 6 carbon atoms, an alkylcarbonyl group having 2 to 6 carbon atoms, a haloalkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a haloalkoxy group having 1 to 6 carbon atoms, a halogen atom, a cyano group, and a nitro group. d is 0, 1, or 2. e is 0 or 1. f is 0 or 1. The dashed line represents a bond to the polymerizable group. However, L B In this, Q B At the end of the side, -Q B -X B - * (* is Q B [2] The composition for a retardation film according to [1], wherein the side chain having a photoreactive moiety is a side chain having a photoreactive moiety and a hydrogen-bonding functional group. [3] The composition for a retardation film according to [1], wherein the side chain having a photoreactive moiety is a side chain represented by any of the following formulas (a1) to (a6): In formulas (a1) to (a6), n1 and n2 each independently represent 0, 1, 2, or 3. L represents a single bond or an alkylene group having 1 to 30 carbon atoms, and one or more hydrogen atoms of the alkylene group may be substituted with a fluorine atom or a monovalent organic group. In addition, -CH2- in L may be -O-, -NR L -, -C(=O)-, -C(=O)-O-, -O-C(=O)-, -C(=O)-NR L -, -NR L -C(=O)-, -NR L —C(═O)—NR L -, -CH=CH-, an alicyclic group, and an aromatic group (where R L each independently represents a hydrogen atom or a monovalent organic group.) However, adjacent -CH2- groups cannot be substituted with these groups at the same time. Q 1 is an aromatic group, a polycyclic aromatic group, an alicyclic group, a phenylenecyclohexylene group, a heterocyclic group, or a fused ring group. 1 When the number of is 2 or more, each Q 1 may be the same or different. 1 and Q2 are each independently a single bond, a phenylene group, or a divalent alicyclic hydrocarbon group having 5 to 8 carbon atoms, and some or all of the hydrogen atoms of the phenylene group may be substituted with a cyano group, a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkylcarbonyl group having 2 to 6 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms. 1 When the number of is 2, each P 1 may be the same or different. 2 When the number of is 2, each Q 2 may be the same or different. 1 and X 2 each independently represents a single bond, —CH—, —O—, —C(═O)—, —N═N—, —CH═CH—, —C≡C—, or —NR X -, -C(=O)-O-, -OC(=O)-, -CH=CH-C(=O)-O-, -OC(=O)-CH=CH-, -C(=O)-NR X -, -NR X —C(═O)— or —NR X —C(═O)—NR X - (However, R X Each of X independently represents a hydrogen atom or an organic group. 1 When the number of is 2 or more, each X 1 may be the same or different, and X 2 When the number of is 2 or more, each X 2 may be the same or different. 1a and Z 2a are each independently a hydrogen atom, a halogen atom, a cyano group, or an alkyl group having 1 to 3 carbon atoms, and some or all of the hydrogen atoms of this alkyl group may be substituted with fluorine atoms. 1 represents a single bond or an alkylene group having 1 to 12 carbon atoms, and some or all of the hydrogen atoms of the alkylene group may be substituted with halogen atoms. 1 , A 2 and D 1 are each independently a single bond, —O—, —CH2—, —C(═O)—O—, —O—C(═O)—, —C(═O)—NH—, or —NH—C(═O)—. 1 When is a single bond, A2 is also a single bond. 1 and Y 2 is a phenylene group or a naphthylene group. R is a hydrogen atom, a cyano group, a halogen atom, a carboxy group, an alkyl group having 1 to 5 carbon atoms, an alkylcarbonyl group having 2 to 6 carbon atoms, a cycloalkyl group having 3 to 7 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms. Cou is a coumarin-6-yl group or a coumarin-7-yl group, and some of the hydrogen atoms bonded to these may be substituted with -NO2, -CN, -CH=C(CN)2, -CH=CH-CN, a halogen atom, an alkyl group having 1 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms. E is -C(=O)-S- or -S-C(=O)-. G 1 and G 2 are each independently N or CH. A hydrogen atom in the ring structure in formulas (a1) to (a6) may be substituted with a substituent selected from an alkyl group having 1 to 6 carbon atoms, an alkylcarbonyl group having 2 to 6 carbon atoms, a haloalkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a haloalkoxy group having 1 to 6 carbon atoms, a halogen atom, a cyano group, and a nitro group. The dashed line represents a bond to the polymerizable group.) [4] The composition for a retardation film according to [3], wherein the side chain having a photoreactive moiety is a side chain represented by the following formula (a1-2): (In formula (a1-2), L, Q 1 , X 1 , Y 1 , Z 1a , Z 2a , R, n1 and the dashed line are defined as in the formula (a1). 1is a 1,4-phenylene group. [6] The composition for a retardation film according to [1], wherein e in formula (b) is 0. [7] The composition for a retardation film according to [6], wherein the number of ring structures in the side chain represented by formula (b) is 3 or less. [8] The composition for a retardation film according to [1], wherein the side chain polymer exhibits liquid crystallinity. [9] A method for producing a single-layer retardation film, comprising the steps of: (I) applying a composition for a retardation film according to any one of [1] to [8] onto a substrate to form a coating film; (II) irradiating the coating film with polarized ultraviolet light; and (III) heating the coating film irradiated with ultraviolet light to obtain a retardation film.

[10] A single-layer retardation film obtained from the composition for a retardation film according to any one of [1] to [8].

[0009] According to the present invention, it is possible to provide a single-layer retardation material that exhibits retardation with little turbidity, and a composition for a retardation film that provides it.

[0010] As a result of intensive research, the inventors have obtained the following findings and have completed the present invention. The retardation film composition (hereinafter also referred to as a polymer composition) of the present invention contains a photosensitive side-chain polymer (hereinafter simply referred to as a side-chain polymer) capable of exhibiting liquid crystallinity. A coating film obtained using the polymer composition is a film containing a photosensitive side-chain polymer capable of exhibiting liquid crystallinity. This coating film is subjected to an alignment treatment by polarized light irradiation without a rubbing treatment. After polarized light irradiation, the side-chain polymer film is heated to form a film imparted with optical anisotropy (hereinafter also referred to as a single-layer retardation material). At this time, the slight anisotropy exhibited by polarized light irradiation serves as a driving force, and the liquid crystalline side-chain polymer itself is efficiently reoriented by self-organization. As a result, a highly efficient alignment treatment is achieved as a single-layer retardation material, and a single-layer retardation material imparted with high optical anisotropy can be obtained.

[0011] In addition, in the polymer composition of the present invention, the polymers of the component (A) are each bonded to one another in such a manner that the number of atoms is the shortest (AC minThe present invention is characterized in that the copolymer has side chains having different mesogenic moieties. As a result, the position of the mesogenic moieties in component (A) is shifted, which weakens the interaction between the mesogenic moieties and suppresses aggregation. Therefore, the retardation material obtained from the polymer composition of the present invention has suppressed molecular crystallinity in the film, thereby suppressing visible haze. Note that these include the inventor's views on the mechanism of the present invention and do not restrict the present invention.

[0012] [Polymer composition] The polymer composition of the present invention has two or more types of side chains (a) having a photoreactive moiety represented by the above formula (a), or has one or more types of the side chains (a) and one or more types of side chains (b) having no photoreactive moiety represented by the above formula (b), and the shortest number of atoms between the side chains (AC min ) are present throughout the entire polymer; and (B) a solvent. The coating film obtained from the composition of the present invention is subjected to an alignment treatment by polarized light irradiation without rubbing. After polarized light irradiation, the side-chain polymer film is heated to form a film (single-layer retardation film) imparted with optical anisotropy. At this time, the slight anisotropy developed by polarized light irradiation serves as a driving force, and the side-chain polymer itself is efficiently reoriented by self-organization. As a result, a highly efficient alignment treatment is achieved for the single-layer retardation film, and a single-layer retardation film imparted with high optical anisotropy can be obtained.

[0013] In addition, the shortest number of atoms (AC min ) is the number of atoms per side chain that is smaller than the number of atoms in the spacer L A or spacer L Band the number of atoms that constitute a part of the polymerizable group and that contribute to the shortest length from the main chain to the end point of the spacer. For example, the shortest number of atoms in *-CH2-* is 1, the shortest number of atoms in *-C(CH3)2-* is 1, the shortest number of atoms in *-(CH2)2-O-(CH2)2-* is 5, and the shortest number of atoms in *-C(=O)-O-* is 2 (* represents a bond). Furthermore, the shortest number of atoms in a 1,4-phenylene group is 4, the shortest number of atoms in a 1,3-phenylene group is 3, the shortest number of atoms in a 1,2-phenylene group is 2, and the shortest number of atoms in a single bond is 0. Furthermore, the main chain in the above definition refers to a polymer moiety, and is a moiety derived from a polymerizable C=C moiety or Si-O moiety of a polymerizable monomer.

[0014] In the present invention, photoreactivity refers to the property of causing one or more of the following reactions: (A-1) photocrosslinking (photodimerization), (A-2) photoisomerization, or (A-3) photo-Fries rearrangement. The side chain polymer preferably has a side chain that causes (A-1) photocrosslinking or (A-2) photoisomerization.

[0015] [(A) Side Chain Polymer] The side chain polymer has two or more types of side chains (a) having a photoreactive moiety represented by the formula (a) above, or has one or more types of side chains (a) and one or more types of side chains (b) having no photoreactive moiety represented by the formula (b), and the shortest number of atoms between the side chains (AC min) are present throughout the polymer. The side chain polymer is (i) a polymer that exhibits liquid crystallinity in a predetermined temperature range and has a photoreactive side chain. The side chain polymer (ii) preferably reacts to light in a wavelength range of 200 to 400 nm, preferably 240 to 400 nm, and exhibits liquid crystallinity in a temperature range of 80 to 300°C. When the substrate used is plastic, the side chain polymer (vi) preferably exhibits liquid crystallinity in a temperature range of 80 to 200°C, more preferably 80 to 150°C, from the viewpoint of the heat resistance of the substrate. The side chain polymer (iii) preferably has a photoreactive side chain that responds to light in a wavelength range of 200 to 400 nm, preferably 240 to 400 nm, particularly polarized ultraviolet light. The side chain polymer (iv) preferably has a mesogenic group to exhibit liquid crystallinity in a temperature range of 80 to 300°C.

[0016] As described above, the side chain polymer has a photoreactive side chain having photoreactivity. The structure of the side chain is not particularly limited, but preferably has a structure that causes the reactions shown in (A-1), (A-2), and / or (A-3) above, and in particular, has a structure that causes (A-1) a photocrosslinking reaction and / or (A-2) a photoisomerization reaction. The structure that causes (A-1) a photocrosslinking reaction is preferred because the structure after the reaction can stably maintain the orientation of the side chain polymer for a long period of time even when exposed to external stress such as heat. Furthermore, the structure that causes (A-2) a photoisomerization reaction is preferred because it enables alignment treatment with a lower exposure dose than photocrosslinking or photofleece transition, thereby improving production efficiency during retardation film production.

[0017] The side chain structure of the side chain polymer preferably has a rigid mesogen component, which stabilizes the alignment of the liquid crystal. Examples of the mesogen component include, but are not limited to, a biphenyl group, a terphenyl group, a phenylcyclohexyl group, and a phenylbenzoate group.

[0018] The side chain represented by formula (a) (hereinafter also referred to as side chain a) contained in the polymer and having a photoreactive moiety that undergoes a photoreaction with ultraviolet light is preferably one represented by any of the following formulae (a1) to (a6): From the viewpoint of solubility in a solvent, the number of benzene rings in one side chain a is preferably three or less.

[0019]

[0020] In formulas (a1) to (a6), n1 and n2 each independently represent 0, 1, 2, or 3. L represents a single bond or an alkylene group having 1 to 30 carbon atoms, and one or more hydrogen atoms of the alkylene group may be substituted with a fluorine atom or a monovalent organic group. In addition, -CHCH- in L may be substituted with -CH=CH-, and -CH- in L may be substituted with -O-, -NR L -, -C(=O)-, -C(=O)-O-, -O-C(=O)-, -C(=O)-NR L -, -NR L -C(=O)-, -NR L —C(═O)—NR L -, -CH=CH-, an alicyclic group, and an aromatic group (where R L each independently represents a hydrogen atom or a monovalent organic group.) However, adjacent -CH2- groups cannot be substituted with these groups at the same time. Q 1 is an aromatic group, a polycyclic aromatic group, an alicyclic group, a phenylenecyclohexylene group, a heterocyclic group, or a fused ring group. 1 When the number of is 2 or more, each Q 1 may be the same or different. 1 and Q 2 are each independently a single bond, a phenylene group, or a divalent alicyclic hydrocarbon group having 5 to 8 carbon atoms, and some or all of the hydrogen atoms of the phenylene group may be substituted with a cyano group, a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkylcarbonyl group having 2 to 6 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms. 1 When the number of is 2, each P 1 may be the same or different. 2 When the number of is 2, each Q 2may be the same or different. 1 and X 2 each independently represents a single bond, —CH—, —O—, —C(═O)—, —N═N—, —CH═CH—, —C≡C—, or —NR X -, -C(=O)-O-, -OC(=O)-, -CH=CH-C(=O)-O-, -OC(=O)-CH=CH-, -C(=O)-NR X -, -NR X —C(═O)— or —NR X —C(═O)—NR X - (However, R X Each of X independently represents a hydrogen atom or a monovalent organic group. 1 When the number of is 2 or more, each X 1 may be the same or different, and X 2 When the number of is 2 or more, each X 2 may be the same or different. 1a and Z 2a are each independently a hydrogen atom, a halogen atom, a cyano group, or an alkyl group having 1 to 3 carbon atoms, and some or all of the hydrogen atoms of this alkyl group may be substituted with fluorine atoms. 1 represents a single bond or an alkylene group having 1 to 12 carbon atoms, and some or all of the hydrogen atoms of the alkylene group may be substituted with halogen atoms. 1 , A 2 and D 1 are each independently a single bond, —O—, —CH2—, —C(═O)—O—, —O—C(═O)—, —C(═O)—NH—, or —NH—C(═O)—. 1 When is a single bond, A 2 is also a single bond. 1 and Y 2is a phenylene group or a naphthylene group. R is a hydrogen atom, a cyano group, a halogen atom, a carboxy group, an alkyl group having 1 to 5 carbon atoms, an alkylcarbonyl group having 2 to 6 carbon atoms, a cycloalkyl group having 3 to 7 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms. Cou is a coumarin-6-yl group or a coumarin-7-yl group, and some of the hydrogen atoms bonded to these may be substituted with -NO2, -CN, -CH=C(CN)2, -CH=CH-CN, a halogen atom, an alkyl group having 1 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms. E is -C(=O)-S- or -S-C(=O)-. G 1 and G 2 are each independently N or CH. A hydrogen atom in the ring structure in formulas (a1) to (a6) may be substituted with a substituent selected from an alkyl group having 1 to 6 carbon atoms, an alkylcarbonyl group having 2 to 6 carbon atoms, a haloalkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a haloalkoxy group having 1 to 6 carbon atoms, a halogen atom, a cyano group, and a nitro group. The dashed lines represent bonds to the polymerizable group.

[0021] The alkylene group having 1 to 30 carbon atoms may be linear, branched, or cyclic, and specific examples thereof include a methylene group, an ethylene group, a propane-1,3-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, a hexane-1,6-diyl group, a heptane-1,7-diyl group, an octane-1,8-diyl group, a nonane-1,9-diyl group, a decane-1,10-diyl group, etc. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0022] The alkyl group having 1 to 5 carbon atoms may be either linear or branched, and specific examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a tert-butyl group, an n-pentyl group, etc. Specific examples of the alkylcarbonyl group having 2 to 6 carbon atoms include a methylcarbonyl (acetyl) group, an ethylcarbonyl group, an n-propylcarbonyl group, an n-butylcarbonyl group, an n-pentylcarbonyl group, etc.

[0023] Specific examples of the alkoxy group having 1 to 5 carbon atoms include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, and an n-pentyloxy group. Specific examples of the divalent alicyclic hydrocarbon group having 5 to 8 carbon atoms include a cyclopentanediyl group, a cyclohexanediyl group, a cycloheptanediyl group, and a cyclooctanediyl group. Specific examples of the cycloalkyl group having 3 to 7 carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group.

[0024] The alkyl group having 1 to 3 carbon atoms may be either linear or branched, and specific examples thereof include a methyl group, an ethyl group, an n-propyl group, and an isopropyl group. The alkylene group having 1 to 12 carbon atoms may be either linear, branched, or cyclic, and specific examples thereof include a methylene group, an ethylene group, a propane-1,3-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, a hexane-1,6-diyl group, a heptane-1,7-diyl group, an octane-1,8-diyl group, a nonane-1,9-diyl group, and a decane-1,10-diyl group. Examples of the monovalent organic group include a methyl group, an ethyl group, and a tert-butoxycarbonyl group.

[0025] The side chain a is more preferably one represented by the following formula (a1-1), (a1-2), (a2-1), (a3-1), (a4-1), (a5-1) or (a6-1).

[0026] (In the formula, L, A 1 , A 2 , Y 1 , Y 2 , P 1 , Q 1 , T 1 , R, X 1 , Z 1a , Z 2a , Cou, E., G. 1 , G 2 , n1 and dashed lines are the same as above.)

[0027] The side chain represented by formula (a1-1) is preferably a side chain represented by the following formula (a1-1-1), and the side chain represented by formula (a1-2) is preferably a side chain represented by formula (a1-2-1).

[0028] (In the formula, n1, L, Q 1 , X 1 , R and dashed lines are the same as above.)

[0029] The side chain represented by formula (a2-1) is preferably a side chain represented by the following formula (a2-1-1).

[0030] (In the formula, L, A 2 , Q 1 , T 1 , R and dashed lines are the same as above.)

[0031] The side chain represented by formula (a3-1) is preferably a side chain represented by the following formula (a3-1-1), (a3-1-2) or (a3-1-3).

[0032] (In the formula, L, C, and the dashed line are the same as above.)

[0033] The side chain represented by formula (a4-1) is preferably a side chain represented by the following formulas (a4-1-1) and (a4-1-2).

[0034] (In the formula, L, R and the dashed line are the same as above.)

[0035] The side chain represented by formula (a5-1) is preferably a side chain represented by the following formula (a5-1-1) or (a5-1-2). (In the formula, L, R and the dashed line are the same as above.)

[0036] The side chain represented by formula (a6-1) is preferably a side chain represented by the following formula (a6-1-1), (a6-1-2) or (a6-1-3).

[0037] (In the formula, L, R and the dashed line are the same as above.)

[0038] As the side chain having a photoreactive site, a side chain of a terminal COOH in which R is H in the side chain represented by (a1-2) above is preferred, and among these, Y1 A side chain in which the group is a 1,4-phenylene group is more preferred.

[0039] The side chain polymer (A) has a photosensitive side chain bonded to its main chain, and can undergo a crosslinking reaction or an isomerization reaction in response to light. The structure of the photosensitive side chain polymer capable of exhibiting liquid crystallinity is not particularly limited as long as it satisfies these properties, but it is preferable that the side chain structure has a rigid mesogen component. When the side chain polymer is used as a single-layer retardation material, stable optical anisotropy can be obtained.

[0040] A more specific example of the structure of the photosensitive side chain type polymer capable of exhibiting liquid crystallinity is preferably a structure having a main chain constituted of at least one selected from the group consisting of radical polymerizable groups such as (meth)acrylate, itaconate, fumarate, maleate, α-methylene-γ-butyrolactone, styrene, vinyl, maleimide, norbornene, and siloxane, and a side chain a.

[0041] The polymer that is the component (A) has a side chain having a photo-alignable moiety represented by the above formula (a) as well as a side chain that does not contain a photo-alignable moiety represented by the following formula (b).

[0042]

[0043] In formula (b), L B is a single bond or a linear or branched alkylene group having 1 to 30 carbon atoms, and one or more hydrogen atoms of the alkylene group may be substituted with a fluorine atom or a monovalent organic group. B -CHCH- in L may be replaced by -CH=CH-, B In the formula, -CH2- is -O-, -NR L -, -C(=O)-, -C(=O)-O-, -O-C(=O)-, -C(=O)-NR L -, -NR L —C(═O)— and —NR L —C(═O)—NR L - (However, R Leach independently represents a hydrogen atom or a monovalent organic group.) However, adjacent -CH2- groups cannot be substituted with these groups at the same time. Q B is an aromatic group, a polycyclic aromatic group, an alicyclic group, a phenylenecyclohexylene group, a heterocyclic group, or a fused ring group. B When the number of is 2 or more, each Q B may be the same or different. B represents a single bond, —CH—, —O—, —C(═O)—, or —NR X -, -C(=O)-O-, -OC(=O)-, -C(=O)-NR X -, -NR X —C(═O)— or —NR X —C(═O)—NR X - (However, R X Each of X independently represents a hydrogen atom or a monovalent organic group. B When the number of is 2 or more, each X B may be the same or different. B is an alkylene group having 1 to 10 carbon atoms, and one or more hydrogen atoms of the alkylene group may be substituted with a fluorine atom or an organic group. B In the formula, -CH2- is -O-, -NR R - (However, R R represents a hydrogen atom or a monovalent organic group. ) and —C(═O)— may be substituted. Adjacent —CH2— may simultaneously be substituted with these groups. R C represents a hydrogen atom or a monovalent organic group. The hydrogen atom in the ring structure in formula (b) may be substituted with a substituent selected from an alkyl group having 1 to 6 carbon atoms, an alkylcarbonyl group having 2 to 6 carbon atoms, a haloalkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a haloalkoxy group having 1 to 6 carbon atoms, a halogen atom, a cyano group, and a nitro group. d is 0, 1, or 2, e is 0 or 1, is 0 or 1, and the dashed line represents a bond to the polymerizable group. However, L B In this, Q B At the end of the side, -Q B -XB - * (* is Q B It does not have a structure represented by the formula (1).

[0044] The number of ring structures in the side chain represented by formula (b) is preferably 3 or less. Here, a ring structure of a fused ring is counted as 1. That is, a phenylene group or a naphthylene group has 1 ring structure, and a biphenylylene group or a cyclohexanediyl group has 2 ring structures.

[0045] The side chain b is preferably, for example, one represented by the following formula (b1).

[0046] (In formula (b1), L B , Q B , X B , R B , R C , d, f and the dashed line are defined as in formula (b).

[0047] A hydrogen atom in the benzene ring in formula (b1) may be substituted with a substituent selected from an alkyl group having 1 to 6 carbon atoms, an alkylcarbonyl group having 2 to 6 carbon atoms, a haloalkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a haloalkoxy group having 1 to 6 carbon atoms, a halogen atom, a cyano group, and a nitro group.

[0048] The side chain polymer (A) exhibits liquid crystallinity in the temperature range of 80 to 300° C., and can further have a side chain that exhibits only liquid crystallinity (hereinafter also referred to as side chain c). Note that "exhibiting only liquid crystallinity" here means that a polymer having only side chain c does not exhibit photoalignment and exhibits only liquid crystallinity during the production process of the retardation material of the present invention (i.e., steps (I) to (III) described below).

[0049] The side chain c is preferably one or two liquid crystalline side chains selected from the group consisting of the following formulae (1) to (6).

[0050]

[0051] In formulas (1) to (6), A 1 , A 2are each independently a single bond, —O—, —CH—, —C(═O)—O—, —O—C(═O)—, —C(═O)—NH—, or —NH—C(═O)—. 11 is —NO2, —CN, a halogen atom, a phenyl group, a naphthyl group, a biphenylyl group, a furanyl group, a monovalent nitrogen-containing heterocyclic group, a monovalent alicyclic hydrocarbon group having 5 to 8 carbon atoms, an alkyl group having 1 to 12 carbon atoms, or an alkyloxy group having 1 to 12 carbon atoms. 12 is a group selected from the group consisting of a phenyl group, a naphthyl group, a biphenylyl group, a furanyl group, a monovalent nitrogen-containing heterocyclic group, a monovalent alicyclic hydrocarbon group having 5 to 8 carbon atoms, and groups obtained by combining these, and a hydrogen atom bonded to the group may be substituted with -NO2, -CN, a halogen atom, an alkyl group having 1 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms. 13 is a hydrogen atom, —NO, —CN, a halogen atom, a phenyl group, a naphthyl group, a biphenylyl group, a furanyl group, a monovalent nitrogen-containing heterocyclic group, a monovalent alicyclic hydrocarbon group having 5 to 8 carbon atoms, an alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. 1 is -C(=O)-O- or -O-C(=O)-. d is an integer of 1 to 12. k1 to k5 are each independently an integer of 0 to 2, provided that the sum of k1 to k5 is 2 or more. k6 and k7 are each independently an integer of 0 to 2, provided that the sum of k6 and k7 is 1 or more. m1 and m2 are each independently an integer of 1 to 3. n is 0 or 1. Z 1 and Z 2 are each independently a single bond, -C(=O)-, -CHO-, or -CF-. Dashed lines represent bonds. A hydrogen atom in the benzene ring in the above formulas (1) to (6) may be substituted with a substituent selected from an alkyl group having 1 to 6 carbon atoms, an alkylcarbonyl group having 2 to 6 carbon atoms, a haloalkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a haloalkoxy group having 1 to 6 carbon atoms, a halogen atom, a cyano group, and a nitro group.

[0052] The side-chain polymer used in the present invention has a photosensitive side chain bonded to its main chain, and is capable of undergoing a crosslinking reaction, an isomerization reaction, or a Fries rearrangement in response to an optimal light wavelength selected from 200 to 400 nm, particularly light with wavelengths of 254 nm, 313 nm, and 365 nm. The structure of the photosensitive side-chain polymer is not particularly limited as long as it satisfies these properties, but it is preferable that the side-chain structure contains a rigid mesogen component. When the side-chain polymer is formed into a single-layer retardation film, stable optical anisotropy can be obtained.

[0053] More specific examples of the structure of the photosensitive side chain type polymer are preferably structures having a main chain constituted of at least one selected from the group consisting of radical polymerizable groups such as (meth)acrylate, itaconate, fumarate, maleate, α-methylene-γ-butyrolactone, styrene, vinyl, maleimide, norbornene, and siloxane, and a side chain a.

[0054] The side chain type polymer used in the present invention can be obtained by polymerizing a monomer that provides side chain a, a monomer that provides side chain b as needed, and a monomer that provides side chain c as needed.

[0055] Examples of the monomer that provides the side chain a (hereinafter also referred to as the monomer MA) include compounds represented by the following formula (M1-1), (M1-2), (M2), (M3), (M4), (M5) or (M6).

[0056] (Wherein PG is a polymerizable group, A 1 , A 2 , D 1 , L, T 1 , Y 1 , Y 2 , P 1 , Q 1 , Q 2 ,R,Cou,E,X 1 , X 2 , Z 1a , Z 2a , G 1 , G 2 , n1 and n2 are the same as above.)

[0057] In formulae (M1-1), (M1-2), (M2), (M3), (M4), (M5), and (M6), PG represents a polymerizable group, and is preferably a group represented by any one of the following formulae (PG1) to (PG12). Of these, an acrylic or methacrylic group represented by formula (PG1) is preferred from the viewpoints of ease of control of the polymerization reaction and stability of the polymer.

[0058] (In the formula, R A is a hydrogen atom or a methyl group, and the dashed line is a bond.

[0059] Here, as described above, the shortest number of atoms (AC min ) is the number of atoms per side chain that is the spacer L A or spacer L B and the number of atoms that constitute part of the polymerizable group and that are related to the shortest length from the main chain to the end point of the spacer, of which the shortest number of atoms in the polymerizable group portion is 7 when the polymerizable group is PG7, 6 when it is PG3, 5 when it is PG4, 4 when it is PG8, 2 when it is PG1, PG2, PG5, PG6 or PG9, 1 when it is PG10, and 0 when it is PG11 or PG12.

[0060] The compound represented by formula (M1-1) is preferably one represented by the following formula (M1-1-1), and the compound represented by formula (M1-2) is preferably one represented by the following formula (M1-2-1).

[0061] (In the formula, PG, L, Q 1 , X 1 , Y 1 , Z 1a , Z 2a , P 1 and R are the same as above.)

[0062] The compound represented by formula (M2) is preferably a compound represented by the following formula (M2-1).

[0063] (Wherein, PG, A 2 , L, T 1 , Y 1 , Z 1a , Z 2a, P 1 , Q 1 and R are the same as above.)

[0064] The compound represented by formula (M3) is preferably a compound represented by the following formula (M3-1).

[0065] (Wherein, PG, A 1 , L, X 1 , Q 1 , Cou and n1 are the same as above.)

[0066] The compound represented by formula (M4) is preferably a compound represented by the following formula (M4-1).

[0067] (Wherein, PG, A 1 , L, X 1 , Y 1 , Y 2 , Q 1 , E, R and n1 are the same as above.)

[0068] The compound represented by formula (M5) is preferably a compound represented by the following formula (M5-1).

[0069] (Wherein, PG, A 1 , L, X 1 , Y 1 , Y 2 , Q 1 , R and n1 are the same as above.)

[0070] The compound represented by formula (M6) is preferably a compound represented by the following formula (M6-1).

[0071] (Wherein, PG, A 1 , L, X 1 , Y 1 , Y 2 , Q 1 , G 1 , G 2 , R and n1 are the same as above.)

[0072] The compound represented by formula (M1-1-1) is preferably one represented by the following formula (M1-1-2), and the compound represented by formula (M1-2-1) is preferably one represented by the following formula (M1-2-2).

[0073] (In the formula, PG, n1, L, Q 1 , X 1 and R are the same as above.)

[0074] The compound represented by formula (M2-1) is preferably a compound represented by the following formula (M2-2).

[0075] (Wherein, PG, A 2 , L, T 1 , Q 1 and R are the same as above.)

[0076] The compound represented by formula (M3-1) is preferably one represented by the following formula (M3-2), (M3-3) or (M3-4).

[0077] (In the formula, PG, L, and Cou are the same as above.)

[0078] The compound represented by formula (M4-1) is preferably one represented by the following formulas (M4-2) and (M4-3).

[0079] (In the formula, PG, L, and R are the same as above.)

[0080] The compound represented by formula (M5-1) is preferably one represented by the following formula (M5-2) or (M5-3).

[0081] (In the formula, PG, L, and R are the same as above.)

[0082] The compound represented by formula (M6-1) is preferably one represented by the following formula (M6-2), (M6-3), or (M6-4).

[0083] (In the formula, PG, L, and R are the same as above.)

[0084] Examples of the compound represented by formula (M1-1) include those represented by any of the following formulas (A-1-1-1) to (A-1-1-13). In the following formulas (A-1-1-1) to (A-1-1-13), PG is a polymerizable group, and s1 represents the number of methylene groups and is an integer of 2 to 9. 11is —H, —CH3, —OCH3, —C(CH3)3, —C(═O)—CH3, or —CN, and R 12 is —H, —CH 3 , —OCH 3 , —CN, or —F.

[0085]

[0086]

[0087]

[0088]

[0089] Examples of the compound represented by formula (M1-2) include those represented by any of the following formulas (A-1-2-1) to (A-1-2-4).

[0090] (In the formula, PG is a polymerizable group, and s1 is the same as above.)

[0091] Specific examples of the compound represented by formula (M1-2) include 4-(6-methacryloxyhexyl-1-oxy)cinnamic acid, 4-(6-acryloxyhexyl-1-oxy)cinnamic acid, 4-(3-methacryloxypropyl-1-oxy)cinnamic acid, and 4-[4-(6-methacryloxyhexyl-1-oxy)benzoyloxy]cinnamic acid.

[0092] Examples of compounds represented by formula (M2) include those represented by any of the following formulae (A-2-1) to (A-2-9). In the following formulae (A-2-1) to (A-2-9), PG is a polymerizable group, and s1 and s2 represent the number of methylene groups and are each independently an integer of 2 to 9. 21 is —CH3, —OCH3, —C(CH3)3, —C(═O)—CH3, —CN, or —F.

[0093]

[0094]

[0095]

[0096] Examples of the compound represented by formula (M3) include those represented by any of the following formulae (A-3-1) to (A-3-5).

[0097] (In the formula, PG is a polymerizable group, and s1 is the same as above.)

[0098] Examples of the compound represented by formula (M4) include those represented by any of the following formulae (A-4-1) and (A-4-2).

[0099] (In the formula, PG is a polymerizable group, and s1 is the same as above.)

[0100] Examples of the compound represented by formula (M5) include those represented by any of the following formulae (A-5-1) to (A-5-3).

[0101] (In the formula, PG is a polymerizable group, and s1 is the same as above.)

[0102] Examples of the compound represented by formula (M6) include those represented by any of the following formulae (A-6-1) to (A-6-3).

[0103] (In the formula, PG is a polymerizable group, and s1 is the same as above.)

[0104] Some of the above-mentioned monomers are commercially available, and others can be produced by the method described in, for example, WO 2014 / 074785.

[0105] As the monomer that gives the side chain a, a compound represented by the above (M1-2) in which R is H and the terminal COOH is preferred, and among them, Y 1 More preferred is a compound in which is a 1,4-phenylene group. PG is preferably any one of (PG1) to (PG5).

[0106] Preferred examples of such monomers include those represented by the following formulas (M1-2-1) to (M1-2-6).

[0107] (In the formula, PG is any one of (PG1) to (PG5) above, and p is an integer of 2 to 9.)

[0108] Examples of the monomer having the structure represented by formula (b) (hereinafter also referred to as monomer MB) include compounds represented by the following formula (MB1).

[0109] (Wherein, PG is any one of (PG1) to (PG5) above, and L B , Q B , X B , R B , R C , d, e, and f are the same as above. A hydrogen atom in the ring structure in the formula may be substituted with a substituent selected from an alkyl group having 1 to 6 carbon atoms, an alkylcarbonyl group having 2 to 6 carbon atoms, a haloalkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a haloalkoxy group having 1 to 6 carbon atoms, a halogen atom, a cyano group, and a nitro group.

[0110] The monomer MB is a compound represented by (MB1) above, C is preferably H, and is represented by the following formula (MB1A):

[0111] (In the formula, PG, L B , Q B , X B , R B , d, e, and f are the same as above. In the formula, a hydrogen atom in the benzene ring may be substituted with a substituent selected from an alkyl group having 1 to 6 carbon atoms, an alkylcarbonyl group having 2 to 6 carbon atoms, a haloalkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a haloalkoxy group having 1 to 6 carbon atoms, a halogen atom, a cyano group, and a nitro group.

[0112] As the monomer MB1A, monomers represented by the following formulae (MB1A-1) to (MB1A-18) are preferred.

[0113]

[0114] (In the formula, PG is any one of (PG1) to (PG5) above, and p is an integer of 2 to 9.)

[0115] Among these monomers, some are commercially available, and others can be produced from known materials by known production methods.

[0116] A monomer having a structure that only exhibits liquid crystallinity in the side chain c (hereinafter also referred to as a monomer LMC) is a monomer that allows a polymer derived from the monomer to exhibit liquid crystallinity.

[0117] The mesogenic group in the side chain c preferably has a structure represented by any one of the following formulae (c1) to (c10).

[0118]

[0119] More specific examples of the monomer LMC include a structure having a polymerizable group derived from at least one selected from the group consisting of radically polymerizable groups such as hydrocarbons, (meth)acrylates, itaconates, fumarates, maleates, α-methylene-γ-butyrolactone, styrenes, vinyls, maleimides, and norbornenes, and siloxanes, and at least one structure represented by the formulas (c1) to (c10). In particular, the monomer LMC is preferably one having a (meth)acrylate as the polymerizable group.

[0120] Preferred examples of the monomer LMC include those represented by the following formulae (LMC-1) to (LMC-6).

[0121] (In the formula, PG is any one of (PG1) to (PG5) above, and p is an integer of 2 to 9.)

[0122] Furthermore, a monomer MD can be copolymerized as a non-liquid crystal side chain d within a range that does not impair photoreactivity and / or liquid crystallinity. Examples of the monomer MD include industrially available radically polymerizable monomers. Specific examples include unsaturated carboxylic acids, acrylic acid ester compounds, methacrylic acid ester compounds, maleimide compounds, acrylonitrile, maleic anhydride, styrene compounds, vinyl compounds, acrylamide compounds, and methacrylamide compounds.

[0123] Specific examples of unsaturated carboxylic acids include acrylic acid, methacrylic acid, itaconic acid, maleic acid, and fumaric acid.

[0124] Examples of acrylic acid ester compounds include methyl acrylate, ethyl acrylate, isopropyl acrylate, benzyl acrylate, naphthyl acrylate, anthryl acrylate, anthrylmethyl acrylate, phenyl acrylate, 2,2,2-trifluoroethyl acrylate, tert-butyl acrylate, cyclohexyl acrylate, isobornyl acrylate, 2-methoxyethyl acrylate, methoxytriethylene glycol acrylate, 2-ethoxyethyl acrylate, tetrahydrofurfuryl acrylate, 3-methoxybutyl acrylate, 2-methyl-2-adamantyl acrylate, 2-propyl-2-adamantyl acrylate, 8-methyl-8-tricyclodecyl acrylate, 8-ethyl-8-tricyclodecyl acrylate, 2-hydroxyethyl acrylate, and 4-hydroxybutyl acrylate.

[0125] Examples of methacrylic acid ester compounds include methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, benzyl methacrylate, naphthyl methacrylate, anthryl methacrylate, anthrylmethyl methacrylate, phenyl methacrylate, 2,2,2-trifluoroethyl methacrylate, tert-butyl methacrylate, cyclohexyl methacrylate, isobornyl methacrylate, 2-methoxyethyl methacrylate, methoxytriethylene glycol methacrylate, 2-ethoxyethyl methacrylate, tetrahydrofurfuryl methacrylate, 3-methoxybutyl methacrylate, 2-methyl-2-adamantyl methacrylate, 2-propyl-2-adamantyl methacrylate, 8-methyl-8-tricyclodecyl methacrylate, 8-ethyl-8-tricyclodecyl methacrylate, 2-hydroxyethyl methacrylate, and glycidyl methacrylate.

[0126] Examples of the maleimide compound include maleimide, N-methylmaleimide, N-phenylmaleimide, N-benzylmaleimide, 4-maleimide butyric acid, N-methoxycarbonylmaleimide, and N-cyclohexylmaleimide.

[0127] Examples of the styrene compound include styrene, 4-methylstyrene, 4-chlorostyrene, 4-bromostyrene, 4-vinylphenylboronic acid, 4-vinylbenzoic acid, and trans-anethole.

[0128] Examples of the vinyl compound include vinyl ether, methyl vinyl ether, benzyl vinyl ether, 2-hydroxyethyl vinyl ether, phenyl vinyl ether, and propyl vinyl ether.

[0129] Examples of the acrylamide compound include acrylamide, N,N-dimethylacrylamide, N-(hydroxymethyl)acrylamide, N-isopropylacrylamide, N-propylacrylamide, N-tert-butylacrylamide, N-(methoxymethyl)acrylamide, and N-(butoxymethyl)acrylamide.

[0130] Examples of methacrylamide compounds include N-methylmethacrylamide, N,N-dimethylmethacrylamide, N-(hydroxymethyl)methacrylamide, N-(methoxymethyl)methacrylamide, N-(butoxymethyl)methacrylamide, and N-(4-hydroxyphenyl)methacrylamide.

[0131] The content of side chain a in the side chain polymer of the present invention is preferably 5 to 90 mol %, more preferably 5 to 80 mol %, and even more preferably 5 to 50 mol % from the viewpoint of photoreactivity. The content of side chain b in the side chain polymer of the present invention is preferably 10 to 95 mol % from the viewpoint of retardation value. When the total content of side chain a and side chain b is less than 100 mol %, the content of side chain c in the side chain polymer of the present invention is 0 to 100 mol % of the remaining portion.

[0132] As described above, the side chain polymer of the present invention may contain the side chain d of a non-liquid crystal component. When the total content of the side chains a to c is less than 100 mol %, the content of the side chain d is the remaining portion.

[0133] The method for producing the side chain polymer of component (A) is not particularly limited, and a general-purpose method used industrially can be used. Specifically, the side chain polymer can be produced by radical polymerization, cationic polymerization, or anionic polymerization using the above-mentioned monomer MA, monomer MB, and optionally monomer LMC and optionally monomer MD. Among these, radical polymerization is particularly preferred from the viewpoint of ease of reaction control, etc.

[0134] As the polymerization initiator for radical polymerization, known compounds such as radical polymerization initiators (radical thermal polymerization initiators, radical photopolymerization initiators) and reversible addition-fragmentation chain transfer (RAFT) polymerization reagents can be used.

[0135] A radical thermal polymerization initiator is a compound that generates radicals when heated to a temperature equal to or higher than its decomposition temperature. Examples of such radical thermal polymerization initiators include ketone peroxides (methyl ethyl ketone peroxide, cyclohexanone peroxide, etc.), diacyl peroxides (acetyl peroxide, benzoyl peroxide, etc.), hydroperoxides (hydrogen peroxide, tert-butyl hydroperoxide, cumene hydroperoxide, etc.), dialkyl peroxides (di-tert-butyl peroxide, dicumyl peroxide, dilauroyl peroxide, etc.), peroxyketals ( dibutylperoxycyclohexane, etc.), alkyl peresters (peroxyneodecanoic acid-tert-butyl ester, peroxypivalic acid-tert-butyl ester, peroxy-2-ethylcyclohexanoic acid-tert-amyl ester, etc.), persulfates (potassium persulfate, sodium persulfate, ammonium persulfate, etc.), azo compounds (azobisisobutyronitrile, 2,2'-di(2-hydroxyethyl)azobisisobutyronitrile, 2,2'-azobis(2-methylpropionate)dimethyl, etc.). The radical thermal polymerization initiators may be used alone or in combination of two or more.

[0136] The radical photopolymerization initiator is not particularly limited as long as it is a compound that initiates radical polymerization by light irradiation. Examples of such radical photopolymerization initiators include benzophenone, Michler's ketone, 4,4'-bis(diethylamino)benzophenone, xanthone, thioxanthone, isopropylxanthone, 2,4-diethylthioxanthone, 2-ethylanthraquinone, acetophenone, 2-hydroxy-2-methylpropiophenone, 2-hydroxy-2-methyl-4'-isopropylpropiophenone, 1-hydroxycyclohexylphenyl ketone, isopropyl benzoin ether, isobutyl benzoin ether, 2-hydroxy-2-methyl-4'-isopropylpropiophenone, 1-hydroxycyclohexylphenyl ketone ... , 2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, camphorquinone, benzanthrone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, 4-dimethylaminobenzoic acid ethyl ester, 4-dimethylaminobenzoic acid isoamyl ester, 4,4'-di(tert-butylperoxycarbonyl)benzophenone, 3,4,4'-tri(tert-butylperoxy carbonyl)benzophenone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2-(4'-methoxystyryl)-4,6-bis(trichloromethyl)-s-triazine, 2-(3',4'-dimethoxystyryl)-4,6-bis(trichloromethyl)-s-triazine, 2-(2',4'-dimethoxystyryl)-4,6-bis(trichloromethyl)-s-triazine, 2-(2'-methoxystyryl)-4,6-bis(trichloromethyl)-s-triazine, 2-(4'-pentyloxy) styryl)-4,6-bis(trichloromethyl)-s-triazine, 4-[p-N,N-di(ethoxycarbonylmethyl)]-2,6-di(trichloromethyl)-s-triazine, 1,3-bis(trichloromethyl)-5-(2'-chlorophenyl)-s-triazine, 1,3-bis(trichloromethyl)-5-(4'-methoxyphenyl)-s-triazine, 2-(p-dimethylaminostyryl)benzoxazole, 2-(p-dimethylaminostyryl)benzthiazole, 2-mercaptobenzothiazole, 3,3'-carbonylbis(7-diethylaminocoumarin), 2-(o-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-biimidazole, 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetrakis(4-ethoxycarbonylphenyl)-1,2'-biimidazole, 2,2'-bis(2,4-dichlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-biimidazole, 2,2'-bis(2 ,4-dibromophenyl)-4,4',5,5'-tetraphenyl-1,2'-biimidazole, 2,2'-bis(2,4,6-trichlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-biimidazole, 3-(2-methyl-2-dimethylaminopropionyl)carbazole, 3,6-bis(2-methyl-2-morpholinopropionyl)-9-n-dodecylcarbazole, 1-hydroxycyclohexyl phenyl ketone, Bis(5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)-phenyl)titanium, 3,3',4,4'-tetra(t-butylperoxycarbonyl)benzophenone, 3,3',4,4'-tetra(t-hexylperoxycarbonyl)benzophenone, 3,3'-di(methoxycarbonyl)-4,4'-di(t-butylperoxycarbonyl)benzophenone, 3,4'- Examples of the radical photopolymerization initiator include di(methoxycarbonyl)-4,3'-di(t-butylperoxycarbonyl)benzophenone, 4,4'-di(methoxycarbonyl)-3,3'-di(t-butylperoxycarbonyl)benzophenone, 2-(3-methyl-3H-benzothiazol-2-ylidene)-1-naphthalen-2-yl-ethanone, and 2-(3-methyl-1,3-benzothiazol-2(3H)-ylidene)-1-(2-benzoyl)ethanone. One type of radical photopolymerization initiator may be used alone, or two or more types may be used in combination.

[0137] The radical polymerization method is not particularly limited, and may be an emulsion polymerization method, a suspension polymerization method, a dispersion polymerization method, a precipitation polymerization method, a bulk polymerization method, a solution polymerization method, or the like.

[0138] The organic solvent used in the polymerization reaction is not particularly limited as long as it dissolves the produced polymer. Specific examples thereof include tetrahydrofuran, cyclopentanone, cyclohexanone, N,N-dimethylformamide, N,N-dimethylacetamide, N,N-diethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-methyl-ε-caprolactam, dimethyl sulfoxide, tetramethylurea, dimethyl sulfone, hexamethyl sulfoxide, γ-butyrolactone, methoxymethylpentanol, dipentene, ethyl amyl ketone, methyl nonyl ketone, methyl ethyl ketone, methyl isoamyl ketone, methyl isopropyl ketone, methyl cellosolve, ethyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, butyl carbitol, ethyl carbitol, ethylene glycol, ethylene glycol monoacetate, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, propylene glycol, and propanediol. Pyrene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol tert-butyl ether, diethylene glycol, diethylene glycol monoacetate, diethylene glycol dimethyl ether, dipropylene glycol monoacetate monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monoacetate monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monoacetate monopropyl ether, 3-methyl-3-methoxybutyl acetate, tripropylene glycol methyl ether, 3-methyl-3-methoxybutanol, diisopropyl ether, ethyl isobutyl ether, diisobutylene, amyl acetate, butyl butyrate, butyl ether, diisobutyl ketone, methylcyclohexene, propyl ether, dihexyl ether, 1,Examples of the organic solvent include 4-dioxane, n-hexane, n-pentane, n-octane, diethyl ether, cyclohexanone, ethylene carbonate, propylene carbonate, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether acetate, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, diglyme, 4-hydroxy-4-methyl-2-pentanone, 3-methoxy-N,N-dimethylpropanamide, 3-ethoxy-N,N-dimethylpropanamide, and 3-butoxy-N,N-dimethylpropanamide. The organic solvents may be used alone or in combination of two or more.

[0139] Furthermore, even if the solvent does not dissolve the polymer to be produced, it may be mixed with the organic solvent described above to the extent that the polymer does not precipitate. In addition, since oxygen in the organic solvent inhibits the polymerization reaction in radical polymerization, it is preferable to use an organic solvent that has been degassed to the greatest extent possible.

[0140] The polymerization temperature during radical polymerization can be selected from any temperature between 30 and 150°C, but is preferably in the range of 50 to 100°C. The reaction can be carried out at any concentration, but if the concentration is too low, it becomes difficult to obtain a high-molecular-weight polymer, and if the concentration is too high, the viscosity of the reaction solution becomes too high, making uniform stirring difficult. Therefore, the monomer concentration is preferably 1 to 50% by mass, more preferably 5 to 30% by mass. The reaction can be carried out at a high concentration at the beginning, and then an organic solvent can be added.

[0141] In the above-mentioned radical polymerization reaction, if the ratio of the radical polymerization initiator to the monomer is high, the molecular weight of the obtained polymer will be small, and if it is low, the molecular weight of the obtained polymer will be large, so the ratio of the radical initiator to the monomer to be polymerized is preferably 0.1 to 15 mol %. Furthermore, various monomer components, solvents, initiators, etc. can also be added during polymerization.

[0142] To recover the polymer produced from the reaction solution obtained by the above reaction, the reaction solution may be poured into a poor solvent to precipitate the polymer. Examples of poor solvents used for precipitation include methanol, acetone, hexane, heptane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, benzene, diethyl ether, methyl ethyl ether, and water. The polymer precipitated by pouring into the poor solvent can be recovered by filtration and then dried at room temperature or by heating under atmospheric or reduced pressure. Furthermore, the recovered polymer can be redissolved in an organic solvent and reprecipitated and recovered 2 to 10 times to reduce the amount of impurities in the polymer. Examples of poor solvents include alcohols, ketones, and hydrocarbons. Using three or more poor solvents selected from these solvents is preferred because it further increases the efficiency of purification.

[0143] The weight average molecular weight of the side chain polymer (A) of the present invention, as measured by Gel Permeation Chromatography (GPC), is preferably from 2,000 to 2,000,000, more preferably from 2,000 to 1,000,000, and even more preferably from 5,000 to 200,000, in consideration of the strength of the resulting coating film, the workability during coating film formation, and the uniformity of the coating film.

[0144] [(B) Organic Solvent] The polymer composition of the present invention contains an organic solvent (good solvent). This organic solvent (good solvent) is not particularly limited as long as it is an organic solvent that dissolves the polymer component. Specific examples thereof include N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methyl-ε-caprolactam, 2-pyrrolidone, N-ethyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, dimethyl sulfoxide, tetramethylurea, pyridine, dimethyl sulfone, hexamethylphosphoramide, γ-butyrolactone, 3-methoxy-N,N-dimethylpropanamide, 3-ethoxy-N,N-dimethylpropanamide ...2-pyrrolidone, N-ethyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, 2-pyrrolidone, N-ethyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, 2-pyrrolidone, N-vinyl-2-pyrrolidone, 2-pyrrolidone, N-ethyl-2-pyrrolidone, 2-pyrrolidone, N-vinyl-2-pyrrolidone, 2-pyrrolidone, N-vinyl-2-pyrrolidone, 2-pyrrolidone, N-vinyl-2-pyrrolidone, 2-pyrrolidone amide, 3-butoxy-N,N-dimethylpropanamide, 1,3-dimethyl-2-imidazolidinone, ethyl amyl ketone, methyl nonyl ketone, methyl ethyl ketone, methyl isoamyl ketone, methyl isopropyl ketone, cyclohexanone, cyclopentanone, ethylene carbonate, propylene carbonate, diglyme, 4-hydroxy-4-methyl-2-pentanone, tetrahydrofuran, tetrahydrofurfuryl alcohol, etc. These may be used alone or in combination of two or more.

[0145] The polymer composition may contain components other than the side chain copolymer and the organic solvent (good solvent), examples of which include, but are not limited to, solvents (poor solvents) or compounds that improve the film thickness uniformity and surface smoothness when the polymer composition is applied, and compounds that improve the adhesion between the retardation film and the substrate.

[0146] Specific examples of solvents (poor solvents) that improve the above-mentioned film thickness uniformity and surface smoothness include isopropyl alcohol, methoxymethyl pentanol, methyl cellosolve, ethyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, butyl carbitol, ethyl carbitol, ethyl carbitol acetate, ethylene glycol, ethylene glycol monoacetate, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether (butyl cellosolve), propylene glycol, propylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol-tert-butyl ether, dipropylene glycol monomethyl ether, diethylene glycol, diethylene glycol monoacetate, diethylene glycol dimethyl ether, dipropylene glycol monoacetate monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monoacetate monoethyl ether, dipropylene glycol monopropyl ether, and dipropylene glycol monoacetate. Monopropyl ether, 3-methyl-3-methoxybutyl acetate, tripropylene glycol methyl ether, 3-methyl-3-methoxybutanol, diisopropyl ether, ethyl isobutyl ether, diisobutylene, amyl acetate, butyl butyrate, butyl ether, diisobutyl ketone, methylcyclohexene, propyl ether, dihexyl ether, 1-hexanol, n-hexane, n-pentane, n-octane, diethyl ether, methyl lactate, ethyl lactate, n-propyl lactate, n-butyl lactate, isoamyl lactate, acetic acid methyl acetate, ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether acetate, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, 1-butoxy-2-propanol, 1-phenoxy-2-propanol, propylene glycol monoacetate,Examples of the poor solvent include solvents having low surface tension such as propylene glycol diacetate, propylene glycol-1-monomethyl ether-2-acetate, propylene glycol-1-monoethyl ether-2-acetate, dipropylene glycol, and 2-(2-ethoxypropoxy)propanol. The poor solvents may be used alone or in combination of two or more.

[0147] When a poor solvent is used, its content in the solvent is preferably 5 to 80% by mass, more preferably 10 to 60% by mass, so as not to significantly reduce the solubility of the polymer.

[0148] Compounds that improve the film thickness uniformity and surface smoothness include fluorine-based surfactants, silicone-based surfactants, and nonionic surfactants. Specific examples of these include F-TOP (registered trademark) 301, EF303, EF352 (manufactured by Tochem Products Co., Ltd.), Megafac (registered trademark) F171, F173, F560, F563, R-30, R-40, R-41 (manufactured by DIC Corporation), Fluorad FC430, FC431 (manufactured by 3M Limited), Asahiguard (registered trademark) AG710 (manufactured by AGC), Surflon (registered trademark) S-382, SC101, SC102, SC103, SC104, SC105, SC106 (manufactured by AGC Seimi Chemical Co., Ltd.), BYK-302, BYK-331, BYK-348, BYK-361N, BYK-381, BYK-3441 (manufactured by BYK Corporation), and the like. The content of these surfactants is preferably from 0.01 to 2 parts by mass, and more preferably from 0.01 to 1 part by mass, per 100 parts by mass of the component (A).

[0149] Specific examples of compounds that improve adhesion between the retardation material and the substrate include functional silane-containing compounds. When a compound that improves adhesion to the substrate is used, the content thereof is preferably 0.1 to 30 parts by mass, more preferably 1 to 20 parts by mass, per 100 parts by mass of the polymer component contained in the polymer composition. If the content is less than 0.1 part by mass, the effect of improving adhesion cannot be expected, and if it is more than 30 parts by mass, the alignment of the retardation material may be deteriorated.

[0150] Furthermore, in order to improve the adhesion between the substrate and the retardation material and to prevent deterioration of characteristics due to backlight when a polarizing plate is constructed, a phenoplast compound or an epoxy group-containing compound may be added to the polymer composition.

[0151] A photosensitizer can also be used as an additive, and as the photosensitizer, a colorless sensitizer and a triplet sensitizer are preferred.

[0152] In addition to the above, the polymer composition of the present invention may contain a dielectric or conductive substance for the purpose of changing the electrical properties such as the dielectric constant and conductivity of the retardation material, and further may contain a crosslinkable compound for the purpose of increasing the hardness and density of the film when made into a retardation material, as long as the effects of the present invention are not impaired.

[0153] [Preparation of polymer composition] The polymer composition of the present invention is preferably prepared as a coating liquid suitable for forming a single-layer retardation material. That is, the polymer composition used in the present invention is preferably prepared as a solution in which the component (A) and the solvent or compound that improves the film thickness uniformity and surface smoothness described above, and the compound that improves the adhesion between the single-layer retardation material and the substrate are dissolved in the organic solvent of the component (B). Here, the content of the component (A) in the composition of the present invention is preferably 1 to 30 mass%, more preferably 5 to 30 mass%.

[0154] The polymer composition of the present invention may contain other polymers in addition to the polymer of component (A) to the extent that the liquid crystallinity and photosensitivity are not impaired. In this case, the content of the other polymers in the polymer component is preferably 0.5 to 80 mass %, more preferably 1 to 50 mass %. Examples of the other polymers include polymers that are not photosensitive side-chain polymers capable of exhibiting liquid crystallinity, such as poly(meth)acrylate, polyamic acid, and polyimide.

[0155] [Single-Layer Retardation Material] The single-layer retardation material of the present invention can be produced by a method including the following steps (I) to (III): (I) a step of applying the composition of the present invention onto a substrate to form a coating film, (II) a step of irradiating the coating film with polarized ultraviolet light, and (III) a step of heating the coating film irradiated with ultraviolet light to obtain a retardation material.

[0156] [Step (I)] Step (I) is a step of applying the composition of the present invention to a substrate to form a coating film. More specifically, the composition of the present invention is applied to a substrate (e.g., a silicon / silicon dioxide-coated substrate, a silicon nitride substrate, a glass substrate coated with a metal (e.g., aluminum, molybdenum, chromium, etc.), a glass substrate, a quartz substrate, an ITO substrate, etc.) or a film (e.g., a resin film such as a triacetyl cellulose (TAC) film, a cycloolefin polymer film, a polyethylene terephthalate film, or an acrylic film) by a method such as bar coating, spin coating, flow coating, roll coating, slit coating, slit coating followed by spin coating, an inkjet method, or a printing method. After application, the solvent is evaporated at 50 to 200°C, preferably 50 to 150°C, using a heating means such as a hot plate, a hot air circulation oven, or an IR (infrared) oven, to obtain a coating film.

[0157] [Step (II)] In step (II), polarized ultraviolet light is irradiated onto the coating film obtained in step (I). When irradiating the surface of the coating film with polarized ultraviolet light, the polarized ultraviolet light is irradiated from a specific direction relative to the substrate via a polarizing plate. As the ultraviolet light, ultraviolet light having a wavelength in the range of 100 to 400 nm can be used. Preferably, an optimal wavelength is selected through a filter or the like depending on the type of coating film used. Then, for example, ultraviolet light having a wavelength in the range of 290 to 400 nm can be selected and used so as to selectively induce a photocrosslinking reaction. As the ultraviolet light, for example, light emitted from a high-pressure mercury lamp can be used.

[0158] The amount of polarized UV light to be irradiated depends on the coating film used. The amount of irradiation is preferably within a range of 1 to 70%, and more preferably within a range of 1 to 50%, of the amount of polarized UV light that achieves the maximum value of ΔA, which is the difference between the UV absorbance in the direction parallel to the polarization direction of the polarized UV light and the UV absorbance in the direction perpendicular to the polarization direction of the polarized UV light in the coating film.

[0159] [Step (III)] In step (III), the coating film irradiated with polarized ultraviolet light in step (II) is heated. By heating, it is possible to impart orientation control ability to the coating film.

[0160] Heating can be performed using a heating means such as a hot plate, a hot air circulation oven, an IR (infrared) oven, etc. The heating temperature can be determined taking into consideration the temperature at which the coating film to be used will exhibit liquid crystallinity.

[0161] The heating temperature is preferably within the temperature range at which the polymer of component (A) contained in the composition of the present invention exhibits liquid crystallinity (hereinafter referred to as the liquid crystal onset temperature). In the case of a thin film surface such as a coating film, the liquid crystal onset temperature at the coating film surface is expected to be lower than the liquid crystal onset temperature when the polymer of component (A) is observed in bulk. Therefore, the heating temperature is more preferably within the liquid crystal onset temperature range at the coating film surface. That is, the temperature range of the heating temperature after irradiation with polarized ultraviolet light is preferably a temperature range having a lower limit 10°C lower than the lower limit of the liquid crystal onset temperature range of the polymer of component (A) and an upper limit 10°C lower than the upper limit of the liquid crystal temperature range. If the heating temperature is lower than this temperature range, the effect of thermally amplifying the anisotropy in the coating film tends to be insufficient. If the heating temperature is too higher than this temperature range, the state of the coating film tends to approach an isotropic liquid state (isotropic phase), in which case it may be difficult to reorient in one direction by self-organization.

[0162] The liquid crystal development temperature refers to a temperature that is equal to or higher than the liquid crystal transition temperature at which a polymer or coating film surface undergoes a phase transition from a solid phase to a liquid crystal phase and equal to or lower than the isotropic phase transition temperature (Tiso) at which a phase transition from a liquid crystal phase to an isotropic phase occurs. For example, developing liquid crystallinity at 130°C or lower means that the liquid crystal transition temperature at which a phase transition from a solid phase to a liquid crystal phase occurs is 130°C or lower.

[0163] The thickness of the coating film formed after heating can be appropriately selected taking into consideration the level difference and optical properties of the substrate used, and is preferably, for example, 0.5 to 10 μm.

[0164] The single-layer retardation material of the present invention obtained in this manner is a material having optical properties suitable for applications such as display devices and recording materials, and is particularly suitable as an optical compensation film such as a polarizing plate and a retardation plate for liquid crystal displays and organic EL displays.

[0165] The present invention will be described in more detail below with reference to synthesis examples, preparation examples, working examples and comparative examples, but the present invention is not limited to the following examples.

[0166] The monomers used in the examples are shown below. The side chain derived from MA-1 is included in the range of side chain (a), and the side chains derived from MB-1 to MB-4 and MC-1 to MC-7 are included in the range of side chain (b). In addition, the shortest number of atoms (AC min ) are as follows: MA-1:9 MB-1:9 MB-2:9 MB-3:9 MB-4:9 MC-1:2 MC-2:5 MC-3:7 MC-4:5 MC-5:7 MC-6:5 MC-7:7

[0167]

[0168] The abbreviations of the other reagents used in this example are as follows: (Organic solvents) CPN: Cyclopentanone NMP: N-methyl-2-pyrrolidone BCS: Butyl cellosolve THF: Tetrahydrofuran MeCN: Acetonitrile (Polymerization initiators) V601: 2,2'-azobis(2-methylpropionate) dimethyl AIBN: 2,2'-azobisisobutyronitrile (Surfactants) F563: Megafac F-563 (manufactured by DIC Corporation) 361N: BYK-361N (manufactured by BYK Corporation) R40: Megafac R-40 (manufactured by DIC Corporation) (Additives) TPTP: Tri-p-tolylphosphine

[0169] [1] Synthesis of Monomers MC-6 and MC-7 are novel compounds not previously disclosed in literature, and their synthesis methods are described in detail below. The products described in Monomer Synthesis Examples 1 and 2 below are 1 Identification was performed by H-NMR analysis (analysis conditions are as follows): Apparatus: Fourier transform superconducting nuclear magnetic resonance spectrometer (FT-NMR) "AVANCE III" (manufactured by BRUKER) 500 MHz Solvent: deuterated dimethyl sulfoxide (DMSO-d6) Standard substance: tetramethylsilane (TMS)

[0170] <Monomer Synthesis Example 1: Synthesis of MC-6>

[0171] MC-4 (10.0 g, 42.3 mmol), one drop of DMF, and THF (30 g) were added to a 200 mL four-neck flask, and oxalyl chloride (5.91 g, 46.6 mmol) was added dropwise and stirred at room temperature (25 ° C). After completion of the reaction, the reaction solution was concentrated using a rotary evaporator to obtain a chlorinated product (light yellow liquid). To the resulting chlorinated product, THF (40 g) and methoxymethyl 3-(4-hydroxyphenyl)propionate (9.36 g, 44.5 mmol, synthesized based on the method described in JP 2016-128403 A) were added, and the mixture was cooled on ice under a nitrogen atmosphere. Triethylamine (EtN, 5.14 g, 50.8 mmol) was added dropwise and stirred at room temperature. After completion of the reaction, the reaction solution was filtered, and the solvent was removed using a rotary evaporator to obtain MC-6-1 (yellow liquid). MC-6-1, MeCN (150 g), and 1N hydrochloric acid (50 g) were added to a 500 mL one-neck flask and stirred at room temperature. After the reaction was completed, the reaction solution was poured into pure water (200 g) and the precipitate was filtered off. The obtained crude product was recrystallized from MeCN to obtain MC-6 (yield: 7.96 g, 20.7 mmol, yield: 48.8%, white solid). 1 The results of H-NMR are shown below, and it was confirmed that the obtained solid was the target MC-6. 1 H-NMR (500MHz, [D6]-DMSO): δ (ppm =) 12.2 (s, 1H), 8.05-8.09 (d, 2H), 7.28-7.32 (d, 2H), 7.13-7.18 (m, 4H), 6.33-6.39 (d , 1H), 6.20-6.26 (m, 1H), 5.96-5.99 (d, 1H), 4.47-4.50 (m, 2H), 4.35-4.39 (m, 2H), 2.82-2.88 (m, 2H), 2.54-2.59 (t, 2H).

[0172] <Monomer Synthesis Example 1: Synthesis of MC-7>

[0173] To a 200 mL four-neck flask, MC-5 (10.0 g, 37.8 mmol), one drop of DMF, and THF (30 g) were added, and oxalyl chloride (5.28 g, 41.6 mmol) was added dropwise and stirred at room temperature. After completion of the reaction, the reaction solution was concentrated using a rotary evaporator to obtain a chlorinated product (light yellow liquid). To the obtained chlorinated product, THF (40 g) and methoxymethyl 3-(4-hydroxyphenyl)propionate (8.35 g, 39.7 mmol) were added, and the mixture was ice-cooled under a nitrogen atmosphere. Triethylamine (4.59 g, 45.4 mmol) was added dropwise and stirred at room temperature. After completion of the reaction, the reaction solution was filtered, and the solvent was distilled off using a rotary evaporator to obtain MC-7-1 (yellow liquid). To a 500 mL one-neck flask, MC-7-1, MeCN (150 g), and 1 N hydrochloric acid (50 g) were added and stirred at room temperature. After the reaction was completed, the reaction mixture was poured into pure water (200 g) and the precipitate was filtered off. The obtained crude product was recrystallized from MeCN to obtain MC-7 (yield: 4.84 g, 11.7 mmol, yield: 31.0%, white solid). 1 The results of H-NMR are shown below, and it was confirmed that the obtained solid was the target MC-7. 1 H-NMR (500MHz, [D6]-DMSO): δ (ppm) = 12.2 (s, 1H), 8.03-8.08 (d, 2H), 7.28-7.32 (d, 2H), 7.08-7.17 (m, 4H), 6.30-6.36 (d , 1H), 6.15-6.22 (m, 1H), 5.92-5.97 (d, 1H), 4.10-4.21 (m, 4H), 2.82-2.87 (m, 2H), 2.54-2.59 (t, 2H), 1.76-1.86 (m, 4H).

[0174] [2] Polymer Synthesis <Synthesis Example 1> MA-1 (2.49 g, 7.5 mmol), MB-1 (7.66 g, 25.0 mmol), MB-4 (3.30 g, 7.5 mmol), MC-1 (1.03 g, 5.0 mmol), MD-1 (0.71 g, 5.0 mmol), and V601 (0.35 g, 1.5 mmol) were dissolved in CPN (37.1 g) to prepare a monomer mixed solution. Under a nitrogen atmosphere, the monomer mixed solution was added dropwise over 1 hour to CPN (15.9 g) heated to 70°C. After completion of the dropwise addition, the mixture was allowed to react at 70°C for 12 hours. After completion of the reaction, the reaction solution was added to a mixed solution of methanol (200 g) and pure water (50 g), and the polymer was reprecipitated. Subsequently, the mixture was filtered, washed with methanol, and dried to obtain polymer powder P-1.

[0175] Comparative Synthesis Example 1 Polymer powder P-R1 was obtained by carrying out the same operations as in Synthesis Example 1, except that the types and amounts (g) of the monomers used were changed as shown in Table 1 below.

[0176] Synthesis Example 2 MA-1 (2.49 g, 7.5 mmol), MB-1 (6.89 g, 22.5 mmol), MB-4 (3.30 g, 7.5 mmol), MC-2 (2.36 g, 10.0 mmol), MD-1 (0.36 g, 2.5 mmol), and V601 (0.58 g, 2.5 mmol) were dissolved in CPN (31.1 g) to prepare a monomer mixed solution. Furthermore, V601 (0.58 g, 2.5 mmol) was dissolved in CPN (6.83 g) to prepare an additional addition solution. Under a nitrogen atmosphere, the monomer mixed solution was added dropwise over 1 hour to CPN (13.3 g) heated to 75°C. Three hours after the completion of the dropwise addition, the additional addition solution was added dropwise over 10 minutes to the above reaction solution at 75°C under a nitrogen atmosphere. After the completion of the dropwise addition, the reaction was allowed to proceed at 75°C for 4 hours. After the reaction was completed, the solution was returned to room temperature to obtain a polymer solution P-2.

[0177] Comparative Synthesis Example 2 Polymer solution P-R2 was obtained by carrying out the same operations as in Synthesis Example 2, except that the types and amounts (g) of the monomers used were changed as shown in Table 1 below.

[0178] Synthesis Example 3 MA-1 (2.49 g, 7.5 mmol), MB-1 (10.72 g, 35.0 mmol), MC-3 (2.09 g, 7.5 mmol), and AIBN (0.82 g, 5.0 mmol) were dissolved in NMP (22.6 g) to prepare a mixed monomer solution. Under a nitrogen atmosphere, the mixed monomer solution was added dropwise to NMP (15.0 g) heated to 60°C over a period of 2 hours. After completion of the addition, the mixture was allowed to react at 60°C for 12 hours. After completion of the reaction, the solution was returned to room temperature to obtain polymer solution P-3.

[0179] <Synthesis Examples 4 to 6, Comparative Synthesis Examples 3 and 4> Polymer solutions P-4 to P-6 and P-R3 to P-R4 were obtained by performing the same operation as in Synthesis Example 3, except that the types and amounts (g) of the monomers used were changed as shown in Table 1 below.

[0180] Synthesis Example 7 MA-1 (2.49 g, 7.5 mmol), MB-1 (6.89 g, 22.5 mmol), MB-4 (3.30 g, 7.5 mmol), MC-4 (1.77 g, 7.5 mmol), MD-1 (0.71 g, 5.0 mmol), and V601 (0.69 g, 3.0 mmol) were dissolved in CPN (38.6 g) to prepare a monomer mixed solution. Furthermore, V601 (0.46 g, 2.0 mmol) was dissolved in CPN (8.73 g) to prepare an additional addition solution. Under a nitrogen atmosphere, the monomer mixed solution was added dropwise over 1 hour to CPN (16.1 g) heated to 70°C. Three hours after the completion of the dropwise addition, the additional addition solution was added dropwise over 10 minutes to the above reaction solution at 70°C under a nitrogen atmosphere. After the completion of the dropwise addition, the reaction was allowed to proceed at 70°C for 6 hours. After the reaction was completed, the reaction mixture was added to a mixed solution of 200 g of methanol and 50 g of pure water to reprecipitate the polymer, which was then filtered, washed with methanol, and dried to obtain polymer powder P-7.

[0181] Synthesis Example 8, Comparative Synthesis Example 5 Polymer solutions P-11 and P-R5 were obtained by performing the same operations as in Synthesis Example 7, except that the types and amounts (g) of the monomers used were changed as shown in Table 1 below.

[0182] Synthesis Example 9 MA-1 (2.49 g, 7.5 mmol), MB-1 (9.96 g, 32.5 mmol), MC-6 (3.84 g, 10.0 mmol), and V601 (0.35 g, 1.5 mmol) were dissolved in CPN (36.9 g) to prepare a monomer mixed solution. Under a nitrogen atmosphere, the monomer mixed solution was added dropwise over 1 hour to CPN (15.8 g) heated to 70°C. After completion of the dropwise addition, the mixture was allowed to react at 70°C for 12 hours. After completion of the reaction, the reaction solution was added to a mixed solution of methanol (200 g) and pure water (50 g), and the polymer was reprecipitated. Subsequently, the mixture was filtered, washed with methanol, and dried to obtain polymer powder P-9.

[0183] Synthesis Example 10, Comparative Synthesis Example 6 Polymer solutions P-10 and P-R6 were obtained by performing the same operations as in Synthesis Example 9, except that the types and amounts (g) of the monomers used were changed as shown in Table 1 below.

[0184] (In Table 1, the numbers in parentheses for the monomer components represent the amount (parts by mole) of each monomer used relative to 100 parts by mole of the total amount of the monomer components used in each polymerization step.)

[0185] [3] Preparation of retardation film-forming material <Preparation Example 1> CPN (9.0 g) and F563 (5.0 mg) were added to the polymer powder P-1 (1.0 g) obtained in Synthesis Example 1 and stirred. This was filtered through a filter with a pore size of 5.0 μm to obtain polymer preparation solution T-1. This polymer preparation solution T-1 was used as it is as a material for forming a retardation film.

[0186] Preparation Example 2 CPN (5.83 g) and 361N (1.0 mg) were added to the polymer solution P-2 (4.17 g, 1.0 g as polymer solid content) obtained in Synthesis Example 2 and stirred. This was filtered through a filter with a pore size of 5.0 μm to obtain polymer preparation solution T-2. This polymer preparation solution T-2 was used as it is as a material for forming a retardation film.

[0187] Preparation Example 3 NMP (0.17 g), BCS (1.50 g), and R40 (1.25 mg) were added to the polymer solution P-3 (8.33 g, 2.5 g as polymer solids) obtained in Synthesis Example 3 and stirred. This was filtered through a filter with a pore size of 5.0 μm to obtain polymer preparation solution T-3. This polymer preparation solution T-3 was used as it is as a material for forming a retardation film.

[0188] <Preparation Examples 4 to 6, Comparative Preparation Examples 3 and 4> As shown in Table 2 below, polymer preparation solutions T-4 to T-6 and TR3 to TR4 were obtained by performing the same operation as in Preparation Example 3, except that the type of polymer solution was changed.

[0189] <Preparation Examples 7 to 10, Comparative Preparation Examples 1, 5 to 6> Polymer preparation solutions T-7 to T-10, T-R1, and T-R5 to T-R6 were obtained by performing the same operation as in Preparation Example 1, except that the type of polymer powder, the amount introduced, and the additives were changed as shown in Table 2 below.

[0190] Comparative Preparation Example 2 Polymer preparation solution T-R2 was obtained by carrying out the same operations as in Preparation Example 2, except that the type of polymer solution was changed as shown in Table 2 below.

[0191]

[0192] [4] Production of Single-Layer Retardation Film Example 1 Polymer Preparation Solution T-1 was applied to a COP film substrate using a bar coater to a film thickness of approximately 3.5 μm. This substrate was dried in a hot air circulating oven at 50° C. for 3 minutes (first drying), and then 100 mJ / cm of ultraviolet light with a wavelength of 365 nm was applied to this substrate from a high-pressure mercury lamp through a cut filter (325 nm low-cut filter) and a polarizer. 2 The film was heated in an IR oven at 115° C. for 10 minutes (second drying) to prepare a substrate S-1 with a retardation film.

[0193] Examples 2, 7 to 8, Comparative Examples 1 to 2, 5 As shown in Table 3 below, the same operations as in Example 1 were performed except that the type of polymer preparation solution, film thickness, baking conditions, and UV exposure dose were changed, thereby obtaining substrates S-2, S-7 to S-8, R-1 to R-2, and R-5 with retardation films.

[0194] Example 3 Polymer Preparation Solution T-3 was applied to a non-alkali glass substrate by spin coating to a film thickness of approximately 4.0 μm. The substrate was dried on a hot plate at 60° C. for 4 minutes, and then 400 mJ / cm of ultraviolet light with a wavelength of 365 nm was applied to the substrate from a high-pressure mercury lamp through a cut filter (365 nm bandpass filter) and a polarizer. 2 The film was heated in an IR oven at 150° C. for 20 minutes to prepare a substrate S-3 with a retardation film.

[0195] Examples 4 to 6, Comparative Examples 3 to 4 As shown in Table 3 below, the same operations as in Example 3 were performed except that the type of polymer preparation solution, film thickness, baking conditions, and UV exposure dose were changed, thereby obtaining substrates S-4 to S-6 and R-3 to R-4 with retardation films.

[0196] Example 9 Polymer Preparation Solution T-9 was applied to a COP film substrate using a bar coater to a film thickness of approximately 4.1 μm. The substrate was dried in a hot air circulating oven at 50° C. for 3 minutes, and then 300 mJ / cm of ultraviolet light with a wavelength of 365 nm was applied to the substrate from a high-pressure mercury lamp through a cut filter (365 nm bandpass filter) and a polarizer. 2 The film was heated in an IR oven at 130° C. for 5 minutes to prepare a substrate S-9 with a retardation film.

[0197] Example 10, Comparative Example 6 Substrates S-10 and R-6 with retardation films were obtained by performing the same operations as in Example 9, except that the type of polymer preparation solution and the film thickness were changed as shown in Table 3 below.

[0198]

[0199] The retardation and haze of each of the retardation film substrates S-1 to S-10 and R-1 to R-6 were evaluated by the following methods.

[0200] [Retardation Evaluation] The linear retardation at a wavelength of 550 nm was measured using AxoScan manufactured by Axometrics, and the results are summarized in Table 4.

[0201] [Haze Evaluation] Using a HAZE METER HZ-V3 manufactured by Suga Test Instruments, the substrate was placed so that the light source light was perpendicular to the substrate, and the haze was measured at room temperature. The results are summarized in Table 4.

[0202]

[0203] From the results of Example 1 and Comparative Example 1, Example 2 and Comparative Example 2, Examples 3 to 5 and Comparative Example 3, Example 6 and Comparative Example 4, Examples 7 to 8 and Comparative Example 5, and Examples 9 to 10 and Comparative Example 6 in Table 4, AC min The single-layer retardation material obtained from the retardation film-forming material having side chains different from AC min The haze value was reduced compared to a single-layer retardation material obtained from a retardation film-forming material that did not have side chains with different lengths. This material exhibits retardation due to the alignment of the liquid crystal side chains, but it is believed that the mesogenic moieties of this liquid crystal component aggregate to form polydomains, causing the haze to worsen. In this invention, by introducing monomers with different spacer lengths, the position of the mesogenic moieties was shifted from their surroundings. This is thought to have suppressed the formation of polydomains, reduced the scattering of light transmitted through the film, and reduced the haze.

Claims

1. (A) Having two or more types of side chains (a) having a photoreactive site represented by the following formula (a), or having one or more types of the side chain (a) and one or more types of side chains (b) having no photoreactive site represented by the following formula (b), and the shortest number of atoms between the side chains (AC min ) is different from each other throughout the polymer, at least one combination of which exists; and (B) a solvent. (In formula (a), n1 is 0, 1, 2 or 3. L A is a single bond or a linear alkylene group having 1 to 30 carbon atoms, and one or more hydrogen atoms of the alkylene group may be substituted with a fluorine atom or a monovalent organic group. A In the formula, -CH2- is -O-, -NR L -, -C(=O)-, -C(=O)-O-, -O-C(=O)-, -C(=O)-NR L --, --NR L -C(=O)-, -NR L -C(=O)-NR L -, -CH=CH-, an alicyclic group, and an aromatic group (wherein R L each independently represents a hydrogen atom or a monovalent organic group. 1 is an aromatic group, a polycyclic aromatic group, an alicyclic group, a phenylenecyclohexylene group, a heterocyclic group, or a fused ring group. 1 When the number of is 2 or more, each Q 1 may be the same or different. 1 represents a single bond, -CH2-, -O-, -C(=O)-, -N=N-, -CH=CH-, -C≡C-, -NR X -, -C(=O)-O-, -OC(=O)-, -CH=CH-C(=O)-O-, -OC(=O)-CH=CH-, -C(=O)-NR X --, --NR X -C(=O)- or -NR X -C(=O)-NR X - (However, R X Each of X independently represents a hydrogen atom or a monovalent organic group. 1 When the number of is 2 or more, each X 1 may be the same or different. Align is a group having a photoreactive site. A hydrogen atom in the ring structure in formula (a) may be substituted with a substituent selected from an alkyl group having 1 to 6 carbon atoms, an alkylcarbonyl group having 2 to 6 carbon atoms, a haloalkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a haloalkoxy group having 1 to 6 carbon atoms, a halogen atom, a cyano group, and a nitro group. The dashed lines represent bonds to the polymerizable group. However, L A In this case, Q 1 At the end of the side, -Q 1 -X 1 -* (* is Q 1 It does not have a structure represented by the following formula: (In formula (b), L B is a single bond or a linear alkylene group having 1 to 30 carbon atoms, and one or more hydrogen atoms of the alkylene group may be substituted with a fluorine atom or a monovalent organic group. B In the formula, -CH2- is -O-, -NR L -, -C(=O)-, -C(=O)-O-, -O-C(=O)-, -C(=O)-NR L --, --NR L -C(=O)-, -NR L -C(=O)-NR L -, -CH=CH-, an alicyclic group, and an aromatic group (wherein R L Each of Q independently represents a hydrogen atom or a monovalent organic group. However, adjacent -CH2- are not simultaneously substituted with these groups. B is an aromatic group, a polycyclic aromatic group, an alicyclic group, a phenylenecyclohexylene group, a heterocyclic group, or a fused ring group. B When the number of is 2 or more, each Q B may be the same or different. B is a single bond, -CH2-, -O-, -C(=O)-, -NR X -, -C(=O)-O-, -OC(=O)-, -C(=O)-NR X --, --NR X -C(=O)- or -NR X -C(=O)-NR X - (However, R X Each of X independently represents a hydrogen atom or a monovalent organic group. B When the number of is 2 or more, each X B may be the same or different. B is an alkylene group having 1 to 10 carbon atoms, and one or more hydrogen atoms of the alkylene group may be substituted with a fluorine atom or an organic group. B In the formula, -CH2- is -O-, -NR R - (However, R R represents a hydrogen atom or a monovalent organic group. ) and -C(=O)- may be substituted. Adjacent -CH2- may be simultaneously substituted with these groups. R C represents a hydrogen atom or a monovalent organic group. The hydrogen atom in the ring structure in formula (b) may be substituted with a substituent selected from an alkyl group having 1 to 6 carbon atoms, an alkylcarbonyl group having 2 to 6 carbon atoms, a haloalkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a haloalkoxy group having 1 to 6 carbon atoms, a halogen atom, a cyano group, and a nitro group. d is 0, 1, or 2. e is 0 or 1. f is 0 or 1. The dashed line represents a bond to a polymerizable group. However, L B In this case, Q B At the end of the side, -Q B -X B -* (* is Q B It does not have a structure represented by the following formula:

2. The composition for a retardation film according to claim 1, wherein the side chain having a photoreactive site is a side chain having a photoreactive site and a functional group capable of bonding with hydrogen.

3. The composition for a retardation film according to claim 1, wherein the side chain having the photoreactive site is a side chain represented by any one of the following formulas (a1) to (a6). In formulae (a1) to (a6), n1 and n2 each independently represent 0, 1, 2, or 3. L represents a single bond or an alkylene group having 1 to 30 carbon atoms, and one or more hydrogen atoms of the alkylene group may be substituted with a fluorine atom or a monovalent organic group. In addition, -CH2- in L represents -O-, -NR L -, -C(=O)-, -C(=O)-O-, -O-C(=O)-, -C(=O)-NR L --, --NR L -C(=O)-, -NR L -C(=O)-NR L -, -CH=CH-, an alicyclic group, and an aromatic group (wherein R L Each of Q independently represents a hydrogen atom or a monovalent organic group. However, adjacent -CH2- are not simultaneously substituted with these groups. 1 is an aromatic group, a polycyclic aromatic group, an alicyclic group, a phenylenecyclohexylene group, a heterocyclic group, or a fused ring group. 1 When the number of is 2 or more, each Q 1 may be the same or different. 1 and Q. 2 are each independently a single bond, a phenylene group, or a divalent alicyclic hydrocarbon group having 5 to 8 carbon atoms, and some or all of the hydrogen atoms of the phenylene group may be substituted with a cyano group, a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkylcarbonyl group having 2 to 6 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms. 1 When the number of is 2, each P 1 may be the same or different. Q 2 When the number of is 2, each Q 2 may be the same or different. X 1 and X 2 each independently represents a single bond, -CH2-, -O-, -C(=O)-, -N=N-, -CH=CH-, -C≡C-, or -NR X -, -C(=O)-O-, -OC(=O)-, -CH=CH-C(=O)-O-, -OC(=O)-CH=CH-, -C(=O)-NR X --, --NR X -C(=O)- or -NR X -C(=O)-NR X - (However, R X Each of X independently represents a hydrogen atom or an organic group. 1 When the number of is 2 or more, each X 1 may be the same or different, X 2 When the number of is 2 or more, each X 2 may be the same or different. 1a and Z 2a are each independently a hydrogen atom, a halogen atom, a cyano group, or an alkyl group having 1 to 3 carbon atoms, and some or all of the hydrogen atoms of this alkyl group may be substituted with fluorine atoms. 1 represents a single bond or an alkylene group having 1 to 12 carbon atoms, and some or all of the hydrogen atoms of the alkylene group may be substituted with halogen atoms. 1 , A 2 and D. 1 are each independently a single bond, -O-, -CH2-, -C(=O)-O-, -O-C(=O)-, -C(=O)-NH-, or -NH-C(=O)-. 1 When is a single bond, A 2 is also a single bond. 1 and Y 2 is a phenylene group or a naphthylene group. R is a hydrogen atom, a cyano group, a halogen atom, a carboxy group, an alkyl group having 1 to 5 carbon atoms, an alkylcarbonyl group having 2 to 6 carbon atoms, a cycloalkyl group having 3 to 7 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms. Cou is a coumarin-6-yl group or a coumarin-7-yl group, and some of the hydrogen atoms bonded to these may be substituted with -NO2, -CN, -CH=C(CN)2, -CH=CH-CN, a halogen atom, an alkyl group having 1 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms. E is -C(=O)-S- or -S-C(=O)-. G 1 and G 2 are each independently N or CH. A hydrogen atom in the ring structure in formulae (a1) to (a6) may be substituted with a substituent selected from an alkyl group having 1 to 6 carbon atoms, an alkylcarbonyl group having 2 to 6 carbon atoms, a haloalkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a haloalkoxy group having 1 to 6 carbon atoms, a halogen atom, a cyano group, and a nitro group. The dashed lines represent bonds to the polymerizable group.) 4. The composition for a retardation film according to claim 3, wherein the side chain having the photoreactive site is a side chain represented by the following formula (a1-2): (In formula (a1-2), L, Q 1 , X 1 , Y 1 , Z 1a , Z 2a , R, n1 and the dashed line are defined as in formula (a1).

5. The above Y 1 The composition for a retardation film according to claim 4, wherein is a 1,4-phenylene group.

6. The composition for a retardation film according to claim 1, wherein e in the formula (b) is 0.

7. The composition for a retardation film according to claim 6, wherein the number of ring structures in the side chain represented by the formula (b) is three or less.

8. The composition for a retardation film according to claim 1, wherein the side chain type polymer exhibits liquid crystallinity.

9. A method for producing a single-layer retardation material, comprising: (I) applying a retardation film composition according to any one of claims 1 to 8 onto a substrate to form a coating film; (II) irradiating the coating film with polarized ultraviolet light; and (III) heating the coating film irradiated with ultraviolet light to obtain a retardation material.

10. A single-layer retardation material obtained from the retardation film composition according to any one of claims 1 to 8.

Images