WO2024162343A1 - Single-layer phase difference material and phase difference film - Google Patents

Abstract

The present invention provides a single-layer phase difference material obtained from a polymer composition where a simple process enables the production of a single-layer phase difference material in which cracking does not occur during transfer, said composition containing: (A) a polymer having side chains that have photo-reactive sites, side chains having non-photo-reactive hydrogen-bonding functional groups, and side chains having self-cross-linking sites; and (B) an organic solvent.

Description

Single-layer retardation material and retardation film

The present invention relates to a single-layer retardation material obtained from a composition containing a polymer. More specifically, the present invention relates to a material having optical properties suitable for applications such as display devices and recording materials, in particular, a single-layer retardation material obtained from a composition containing a liquid crystal polymer that can be suitably used for optical compensation films such as polarizing plates and retardation plates for liquid crystal displays and organic EL (Electro Luminescence) display devices, and a retardation film made from the single-layer retardation material.

The demand for improved display quality and lighter weight for liquid crystal displays and organic EL displays has led to an increased 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 that utilize the optical anisotropy of polymerizable liquid crystal compounds are being developed. The polymerizable liquid crystal compounds used here are generally liquid crystal compounds that have a polymerizable group and a liquid crystal structural portion (a structural portion having a spacer portion and a mesogen portion), and acrylic groups are commonly used as the polymerizable group.

Such polymerizable liquid crystal compounds are generally made into polymers (films) by polymerizing them through exposure to 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 aligned supports, and this compound is irradiated with radiation while 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 to a composition in which this mixture is mixed with chiral liquid crystal, and then ultraviolet light is irradiated to obtain a polymer (Patent Document 2).

Also, 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 that contain photocrosslinking sites (Patent Documents 5 and 6).

On the other hand, since it may be more efficient to peel such single-layer coating films from the substrate and transfer them to an adhesive film or the like, there is a demand for films that can withstand transfer depending on the process, but it has become clear that cracks may occur during transfer.

Japanese Unexamined Patent Publication No. 62-70407 Japanese Patent Application Publication No. 9-208957 EP 1 090 325 A1 International Publication No. 2008/031243 JP 2008-164925 A Japanese Patent Application Publication No. 11-189665

The present invention has been made in consideration of the above problems, and aims to provide a single-layer retardation material and a retardation film obtained from a polymer composition that enables the production of a single-layer retardation material that does not cause cracks during transfer through a simpler process.

As a result of extensive research into solving the above problems, the inventors discovered that by using a composition containing a specific polymer, it is possible to obtain a single-layer retardation material and retardation film that do not crack during transfer, and thus completed the present invention.

（式（ａ１）～（ａ６）中、ｎ１及びｎ２は、それぞれ独立に、０、１、２又は３である。Ｌは、単結合又は炭素数１～１２のアルキレン基であり、該アルキレン基の水素原子の一部又は全部がハロゲン原子で置換されていてもよい。Ｔ¹は、単結合又は炭素数１～１２のアルキレン基であり、該アルキレン基の水素原子の一部又は全部がハロゲン原子で置換されていてもよい。Ａ¹、Ａ²及びＤ¹は、それぞれ独立に、単結合、－Ｏ－、－ＣＨ₂－、－Ｃ（＝Ｏ）－Ｏ－、－Ｏ－Ｃ（＝Ｏ）－、－Ｃ（＝Ｏ）－ＮＨ－又は－ＮＨ－Ｃ（＝Ｏ）－である。ただし、Ｔ¹が単結合のときは、Ａ²も単結合である。Ｙ¹及びＹ²は、フェニレン基又はナフチレン基であり、該フェニレン基及びナフチレン基の水素原子の一部又は全部が、シアノ基、ハロゲン原子、炭素数１～５のアルキル基、炭素数２～６のアルキルカルボニル基又は炭素数１～５のアルコキシ基で置換されていてもよい。Ｐ¹、Ｑ¹及びＱ²は、それぞれ独立に、単結合、フェニレン基又は炭素数５～８の２価の脂環式炭化水素基であり、該フェニレン基の水素原子の一部又は全部が、シアノ基、ハロゲン原子、炭素数１～５のアルキル基、炭素数２～６のアルキルカルボニル基又は炭素数１～５のアルコキシ基で置換されていてもよい。Ｑ¹の数が２のとき、各Ｑ¹は互いに同一でも異なっていてもよく、Ｑ²の数が２のとき、各Ｑ²は互いに同一でも異なっていてもよい。Ｒは、水素原子、シアノ基、ハロゲン原子、カルボキシ基、炭素数１～５のアルキル基、炭素数２～６のアルキルカルボニル基、炭素数３～７のシクロアルキル基又は炭素数１～５のアルコキシ基である。Ｘ¹及びＸ²は、それぞれ独立に、単結合、－Ｏ－、－Ｃ（＝Ｏ）－Ｏ－、－Ｏ－Ｃ（＝Ｏ）－、－Ｎ＝Ｎ－、－ＣＨ＝ＣＨ－、－Ｃ≡Ｃ－、－ＣＨ＝ＣＨ－Ｃ（＝Ｏ）－Ｏ－又は－Ｏ－Ｃ（＝Ｏ）－ＣＨ＝ＣＨ－である。Ｘ¹の数が２のとき、各Ｘ¹は互いに同一でも異なっていてもよく、Ｘ²の数が２のとき、各Ｘ²は互いに同一でも異なっていてもよい。Ｚ^1a及びＺ^2aは、それぞれ独立に、水素原子、ハロゲン原子、シアノ基又は炭素数１～３のアルキル基であり、このアルキル基の水素原子の一部または全部はフッ素原子により置換されていてもよい。Ｃｏｕは、クマリン－６－イル基又はクマリン－７－イル基であり、これらに結合する水素原子の一部が－ＮＯ₂、－ＣＮ、－ＣＨ＝Ｃ（ＣＮ）₂、－ＣＨ＝ＣＨ－ＣＮ、ハロゲン原子、炭素数１～５のアルキル基又は炭素数１～５のアルコキシ基で置換されてもよい。Ｅは、－Ｃ（＝Ｏ）－Ｏ－、－Ｏ－Ｃ（＝Ｏ）－、－Ｃ（＝Ｏ）－Ｓ－又は－Ｓ－Ｃ（＝Ｏ）－である。Ｇ¹及びＧ²は、それぞれ独立に、Ｎ又はＣＨである。破線は、結合手である。）
＜４＞　光反応性部位を有する側鎖が、下記式（ａ１－２）で表される上記＜１＞に記載の光反応性部位を有する側鎖を有する側鎖型重合体を含有する単層位相差材。

（式中、ｎ１は、０、１又は２である。Ｌは、単結合又は炭素数１～１２のアルキレン基であり、該アルキレン基の水素原子の一部又は全部がハロゲン原子で置換されていてもよい。Ｑ¹は単結合、フェニレン基又は炭素数５～８の２価の脂環式炭化水素基であり、該フェニレン基の水素原子の一部又は全部が、シアノ基、ハロゲン原子、炭素数１～５のアルキル基、炭素数２～６のアルキルカルボニル基又は炭素数１～５のアルコキシ基で置換されていてもよい。Ｑ¹の数が２のとき、各Ｑ¹は互いに同一でも異なっていてもよい。Ｘ¹は、単結合、－Ｏ－、－Ｃ（＝Ｏ）－Ｏ－、－Ｏ－Ｃ（＝Ｏ）－、－Ｎ＝Ｎ－、－ＣＨ＝ＣＨ－、－Ｃ≡Ｃ－、－ＣＨ＝ＣＨ－Ｃ（＝Ｏ）－Ｏ－又は－Ｏ－Ｃ（＝Ｏ）－ＣＨ＝ＣＨ－である。Ｘ¹の数が２のとき、各Ｘ¹は互いに同一でも異なっていてもよい。Ｙ¹は、フェニレン基又はナフチレン基である。Ｚ^1a及びＺ^2aは、それぞれ独立に、水素原子、ハロゲン原子、シアノ基又は炭素数１～３のアルキル基であり、このアルキル基の水素原子の一部または全部はフッ素原子により置換されていてもよい。Ｒは水素原子である。）
＜５＞　Ｙ¹が１，４－フェニレン基である＜４＞に記載の単層位相差材。
＜６＞　（Ａ）成分である重合体が、さらにヒドロキシアルキル基を有する側鎖を有する上記＜１＞に記載の単層位相差材。
＜７＞　（Ａ）成分である重合体が、下記式（ｂ）で表される部位を有する側鎖を有する上記＜１＞に記載の単層位相差材。

（式中、Ｒ¹は、炭素数１～３０のアルキレン基であり、該アルキレン基の１つ又は複数の水素原子が、フッ素原子又は有機基で置換されていてもよい。また、Ｒ¹中の－ＣＨ₂ＣＨ₂－が、－ＣＨ＝ＣＨ－で置換されていてもよく、Ｒ¹中の－ＣＨ₂－が、－Ｏ－、－ＮＨ－Ｃ（＝Ｏ）－、－Ｃ（＝Ｏ）－ＮＨ－、－Ｃ（＝Ｏ）－Ｏ－、－Ｏ－Ｃ（＝Ｏ）－、－ＮＨ－、－ＮＨ－Ｃ（＝Ｏ）－ＮＨ－及び－Ｃ（＝Ｏ）－からなる群から選ばれる基で置換されていてもよい。ただし、隣接する－ＣＨ₂－が同時にこれらの基で置換されることはない。
　Ｒ⁴は、芳香族基、多環芳香族基、脂環族基、フェニレンシクロへキシレン基、複素環式基又は縮合環式基である。
　Ｒ⁵は、－ＣＨ₂－、－Ｏ－、－ＮＨ－、－Ｃ（＝Ｏ）－、－Ｃ（＝Ｏ）－Ｏ－、－Ｏ－Ｃ（＝Ｏ）－、－ＣＨ＝ＣＨ－Ｃ（＝Ｏ）－Ｏ－、－Ｃ（＝Ｏ）－ＮＨ－、－ＮＨ－Ｃ（＝Ｏ）－又は－ＮＨ－Ｃ（＝Ｏ）－ＮＨ－である。
　Ｒ⁶は、炭素数１～１０のアルキレン基であり、該アルキレン基の１つ又は複数の水素原子が、フッ素原子又は有機基で置換されていてもよい。また、Ｒ⁶中の－ＣＨ₂－が、－Ｏ－、－ＮＨ－及び－Ｃ（＝Ｏ）－からなる群から選ばれる基で置換されていてもよい。隣接する－ＣＨ₂－が同時にこれらの基で置換されていてもよい。
　式（ｂ）中の環構造中の水素原子は、炭素数１～６のアルキル基、炭素数１～６のハロアルキル基、炭素数１～６のアルコキシ基、炭素数１～６のハロアルコキシ基、ハロゲン基、シアノ基及びニトロ基から選ばれる置換基で置換されていてもよい。
　ｄは、０、１又は２である。
　ｅは、０又は１である。
　ｆは、０又は１である。
　破線は、結合手である。）
＜８＞　上記式（ｂ）で表される側鎖中の環構造が３個以下である、＜７＞に記載の単層位相差材。
＜９＞　側鎖型重合体が、液晶性を発現する＜１＞に記載の単層位相差材。
＜１０＞　＜９＞に記載の単層位相差材から得られる位相差フィルム。 Accordingly, the present invention provides a single-layer retardation material obtained from the following polymer composition.
<1> A single-layer retardation material obtained from a polymer composition containing: (A) a polymer having a side chain having a photoreactive site, a side chain having a non-photoreactive hydrogen-bonding functional group, and a side chain having a self-crosslinking site; and (B) an organic solvent.
<2> The single-layer retardation material according to <1>, wherein the side chain having the photoreactive site is a side chain having a photoreactive site and a hydrogen-bonding functional group.
<3> The single-layer retardation material according to <1>, wherein the side chain having a photoreactive site is a side chain represented by any one of the following formulas (a1) to (a6):

(In formulas (a1) to (a6), n1 and n2 are each independently 0, 1, 2, or 3. L is 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. T ¹ is 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. A ¹ , A ² , and D ¹ are each independently a single bond, -O-, -CH ₂ -, -C(═O)-O-, -O-C(═O)-, -C(═O)-NH-, or -NH-C(═O)-. However, when T ¹ is a single bond, A ² is also a single bond. Y ¹ and Y P 1 , Q 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. When the number of Q ^1s is ² , each Q ¹ may be the same or different from the others, and when the number of Q ^2s is 2, each Q ² may be the same or different from each other. 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. X ¹ and X ² are each independently a single bond, -O-, -C(=O)-O-, -O-C(=O)-, -N=N-, -CH=CH-, -C≡C-, -CH=CH-C(=O)-O-, or -O-C(=O)-CH=CH-. When the number of X ¹ is 2, each X ¹ may be the same or different from each other, and when the number of X ² is 2, each X ² may be the same or different from each other. Z ^1a and Z Each of ^2a is 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. 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 -NO ₂ , -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)-O-, -O-C(=O)-, -C(=O)-S-, or -S-C(=O)-. Each of G ¹ and G ² is independently N or CH. The dashed lines represent bonds.)
<4> A single-layer retardation material containing a side chain-type polymer having a side chain having a photoreactive site according to the above <1>, wherein the side chain having a photoreactive site is represented by the following formula (a1-2):

(In the formula, n1 is 0, 1 or 2. L is 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. Q ¹ is 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. When the number of Q ¹ is 2, each Q ¹ may be the same or different. X ¹ is a single bond, -O-, -C(=O)-O-, -O-C(=O)-, -N=N-, -CH=CH-, -C≡C-, -CH=CH-C(=O)-O-, or -O-C(=O)-CH=CH-. X When the number of ^{X 1} is 2, each X ¹ may be the same or different. Y ¹ is a phenylene group or a naphthylene group. Z ^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. R is a hydrogen atom.
<5> The single-layer retardation material according to <4>, wherein Y ¹ is a 1,4-phenylene group.
<6> The single-layer retardation material according to the above item <1>, wherein the polymer (A) further has a side chain having a hydroxyalkyl group.
<7> The single-layer retardation material according to the above <1>, wherein the polymer as the component (A) has a side chain having a moiety represented by the following formula (b):

(In the formula, R ¹ is 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 an organic group. Furthermore, -CH ₂ CH ₂ - in R ¹ may be substituted with -CH=CH-, and -CH ₂ - in R ¹ may be substituted with a group selected from the group consisting of -O-, -NH-C(=O)-, -C(=O)-NH-, -C(=O)-O-, -O-C(=O)-, -NH-, -NH-C(=O)-NH- and -C(=O)-. However, adjacent -CH ₂ -'s are not substituted with these groups at the same time.
^R4 is an aromatic group, a polycyclic aromatic group, an alicyclic group, a phenylenecyclohexylene group, a heterocyclic group, or a fused ring group.
^R5 is _-CH2- , -O-, -NH-, -C(=O)-, -C(=O)-O-, -O-C(=O)-, -CH=CH-C(=O)-O-, -C(=O)-NH-, -NH-C(=O)- or -NH-C(=O)-NH-.
R ⁶ 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. In addition, -CH ₂ - in R ⁶ may be substituted with a group selected from the group consisting of -O-, -NH-, and -C(═O)-. Adjacent -CH ₂ - may also be substituted with these groups at the same time.
A 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, 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 group, 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 lines represent bonds.)
<8> The single-layer retardation material according to <7>, wherein the number of ring structures in the side chain represented by the formula (b) is three or less.
<9> The single-layer retardation material according to <1>, wherein the side chain polymer exhibits liquid crystallinity.
<10> A retardation film obtained from the single-layer retardation material according to <9>.

The present invention makes it possible to provide a single-layer retardation material and retardation film that do not crack during transfer.

As a result of intensive research, the present inventors have obtained the following findings and have completed the present invention.
The polymer composition (composition for retardation film) used in the preparation of the single-layer retardation material of the present invention has a photosensitive side-chain polymer (hereinafter, also simply referred to as a side-chain polymer) capable of expressing liquid crystallinity, and the coating film obtained using the polymer composition is a film having a photosensitive side-chain polymer capable of expressing liquid crystallinity. This coating film is subjected to an orientation treatment by polarized light irradiation without rubbing treatment. Then, after the polarized light irradiation, the side-chain polymer film is heated to become a film (single-layer retardation material) to which optical anisotropy has been imparted. At this time, the slight anisotropy expressed by the polarized light irradiation becomes a driving force, and the liquid crystal side-chain polymer itself is efficiently reoriented by self-organization. As a result, a highly efficient orientation treatment is realized as a single-layer retardation material, and a single-layer retardation material to which high optical anisotropy has been imparted can be obtained.

In addition, in the polymer composition of the present invention, the side chain type polymer has a side chain with a self-crosslinking site, which causes a crosslinking reaction and increases the strength of the film. Note that these include the inventor's views on the mechanism of the present invention and do not restrict the present invention.

Hereinafter, embodiments of the present invention will be described in detail.
[Polymer composition]
The polymer composition used in the present invention contains (A) a polymer having a side chain having a photoreactive site, a side chain having a non-photoreactive hydrogen-bonding functional group, and a side chain having a self-crosslinking site (hereinafter also referred to as a side chain type polymer); and (B) an organic solvent. The coating film obtained from the above composition is oriented by polarized light irradiation without rubbing. After the polarized light irradiation, the side chain type polymer film is heated to form a film (single-layer retardation film) with optical anisotropy. At this time, the slight anisotropy developed by the polarized light irradiation becomes a driving force, and the side chain type polymer itself is efficiently reoriented by self-organization. As a result, a highly efficient orientation process is realized as a single-layer retardation film, and a single-layer retardation film with high optical anisotropy can be obtained.

In the present invention, photoreactivity refers to the property of causing either (A-1) a photocrosslinking (photodimerization) reaction, (A-2) a photoisomerization, or (A-3) a photo-Fries rearrangement reaction; or a combination of these reactions. The above side chain type polymer preferably has a side chain that causes (A-1) a photocrosslinking reaction or (A-2) a photoisomerization reaction.

The side chain polymer is (i) a polymer that exhibits liquid crystallinity in a specific temperature range and has a photoreactive side chain. The side chain polymer is (ii) preferably reacts to light in the wavelength range of 200 to 400 nm, preferably 240 to 400 nm, and exhibits liquid crystallinity in the temperature range of 50 to 300°C. The side chain polymer is (iii) preferably has a photoreactive side chain that reacts to light in the wavelength range of 200 to 400 nm, preferably 240 to 400 nm, particularly polarized ultraviolet light. The side chain polymer is (iv) preferably has a mesogen group to exhibit liquid crystallinity in the temperature range of 50 to 300°C.

The side chain polymer has a photoreactive side chain having photoreactivity as described above. The structure of the side chain is not particularly limited, but has a structure that causes the reactions shown in (A-1), (A-2) and/or (A-3) above, and in particular, it is preferable that the side chain has a structure that causes the (A-1) photocrosslinking reaction and/or the (A-2) photoisomerization reaction. The (A-1) structure that causes the photocrosslinking reaction is preferable in that the structure after the reaction can stably maintain the orientation of the side chain polymer for a long period of time even if it is exposed to external stress such as heat. The (A-2) structure that causes the photoisomerization reaction is preferable in that it allows orientation treatment with a lower exposure amount compared to photocrosslinking and photofleece transition, and can increase production efficiency when manufacturing retardation films.

The side chain structure of the side chain type polymer preferably has a rigid mesogen component, since this stabilizes the alignment of the liquid crystal. Examples of mesogen components include, but are not limited to, a biphenyl group, a terphenyl group, a phenylcyclohexyl group, a phenylbenzoate group, etc.

（式（ａ１）～（ａ６）中、ｎ１及びｎ２は、それぞれ独立に、０、１、２又は３である。Ｌは、単結合又は炭素数１～１２のアルキレン基であり、該アルキレン基の水素原子の一部又は全部がハロゲン原子で置換されていてもよい。Ｔ¹は、単結合又は炭素数１～１２のアルキレン基であり、該アルキレン基の水素原子の一部又は全部がハロゲン原子で置換されていてもよい。Ａ¹、Ａ²及びＤ¹は、それぞれ独立に、単結合、－Ｏ－、－ＣＨ₂－、－Ｃ（＝Ｏ）－Ｏ－、－Ｏ－Ｃ（＝Ｏ）－、－Ｃ（＝Ｏ）－ＮＨ－又は－ＮＨ－Ｃ（＝Ｏ）－である。ただし、Ｔ¹が単結合のときは、Ａ²も単結合である。Ｙ¹及びＹ²は、フェニレン基又はナフチレン基であり、該フェニレン基及びナフチレン基の水素原子の一部又は全部が、シアノ基、ハロゲン原子、炭素数１～５のアルキル基、炭素数２～６のアルキルカルボニル基又は炭素数１～５のアルコキシ基で置換されていてもよい。Ｐ¹、Ｑ¹及びＱ²は、それぞれ独立に、単結合、フェニレン基又は炭素数５～８の２価の脂環式炭化水素基であり、該フェニレン基の水素原子の一部又は全部が、シアノ基、ハロゲン原子、炭素数１～５のアルキル基、炭素数２～６のアルキルカルボニル基又は炭素数１～５のアルコキシ基で置換されていてもよい。Ｑ¹の数が２のとき、各Ｑ¹は互いに同一でも異なっていてもよく、Ｑ²の数が２のとき、各Ｑ²は互いに同一でも異なっていてもよい。Ｒは、水素原子、シアノ基、ハロゲン原子、カルボキシ基、炭素数１～５のアルキル基、炭素数２～６のアルキルカルボニル基、炭素数３～７のシクロアルキル基又は炭素数１～５のアルコキシ基である。Ｘ¹及びＸ²は、それぞれ独立に、単結合、－Ｏ－、－Ｃ（＝Ｏ）－Ｏ－、－Ｏ－Ｃ（＝Ｏ）－、－Ｎ＝Ｎ－、－ＣＨ＝ＣＨ－、－Ｃ≡Ｃ－、－ＣＨ＝ＣＨ－Ｃ（＝Ｏ）－Ｏ－又は－Ｏ－Ｃ（＝Ｏ）－ＣＨ＝ＣＨ－である。Ｘ¹の数が２のとき、各Ｘ¹は互いに同一でも異なっていてもよく、Ｘ²の数が２のとき、各Ｘ²は互いに同一でも異なっていてもよい。Ｚ^1a及びＺ^2aは、それぞれ独立に、水素原子、ハロゲン原子、シアノ基又は炭素数１～３のアルキル基であり、このアルキル基の水素原子の一部または全部はフッ素原子により置換されていてもよい。Ｃｏｕは、クマリン－６－イル基又はクマリン－７－イル基であり、これらに結合する水素原子の一部が－ＮＯ₂、－ＣＮ、－ＣＨ＝Ｃ（ＣＮ）₂、－ＣＨ＝ＣＨ－ＣＮ、ハロゲン原子、炭素数１～５のアルキル基又は炭素数１～５のアルコキシ基で置換されてもよい。Ｅは、－Ｃ（＝Ｏ）－Ｏ－、－Ｏ－Ｃ（＝Ｏ）－、－Ｃ（＝Ｏ）－Ｓ－又は－Ｓ－Ｃ（＝Ｏ）－である。Ｇ¹及びＧ²は、それぞれ独立に、Ｎ又はＣＨである。破線は、結合手である。） The side chain having a photoreactive site that undergoes a photoreaction with ultraviolet light (hereinafter also referred to as side chain a) contained in the above polymer is preferably one represented by any of the following formulas (a1) to (a6): From the viewpoint of solubility in a solvent, the number of benzene rings in one side chain a is preferably 3 or less.

(In formulas (a1) to (a6), n1 and n2 are each independently 0, 1, 2, or 3. L is 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. T ¹ is 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. A ¹ , A ² , and D ¹ are each independently a single bond, -O-, -CH ₂ -, -C(═O)-O-, -O-C(═O)-, -C(═O)-NH-, or -NH-C(═O)-. However, when T ¹ is a single bond, A ² is also a single bond. Y ¹ and Y P 1 , Q 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. When the number of Q ^1s is ² , each Q ¹ may be the same or different from the others, and when the number of Q ^2s is 2, each Q ² may be the same or different from each other. 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. X ¹ and X ² are each independently a single bond, -O-, -C(=O)-O-, -O-C(=O)-, -N=N-, -CH=CH-, -C≡C-, -CH=CH-C(=O)-O-, or -O-C(=O)-CH=CH-. When the number of X ¹ is 2, each X ¹ may be the same or different from each other, and when the number of X ² is 2, each X ² may be the same or different from each other. Z ^1a and Z Each of ^2a is 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. 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 -NO ₂ , -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)-O-, -O-C(=O)-, -C(=O)-S-, or -S-C(=O)-. Each of G ¹ and G ² is independently N or CH. The dashed lines represent bonds.)

The alkylene group having 1 to 12 carbon atoms may be linear, branched, or cyclic, and specific examples include methylene, ethylene, propane-1,3-diyl, butane-1,4-diyl, pentane-1,5-diyl, hexane-1,6-diyl, heptane-1,7-diyl, octane-1,8-diyl, nonane-1,9-diyl, and decane-1,10-diyl.

The above halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, etc.

The alkyl group having 1 to 5 carbon atoms may be either linear or branched, and specific examples include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a tert-butyl group, and an n-pentyl group.

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, and an n-pentylcarbonyl group.

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.

The alkyl group having 1 to 3 carbon atoms may be either linear or branched, and specific examples include a methyl group, an ethyl group, an n-propyl group, and an isopropyl group.

（式中、Ｌ、Ａ¹、Ａ²、Ｙ¹、Ｙ²、Ｐ¹、Ｑ¹、Ｔ¹、Ｒ、Ｘ¹、Ｚ^1a、Ｚ^2a、Ｃｏｕ、Ｅ、Ｇ¹、Ｇ²、ｎ１及び破線は、上記と同じ。） 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).

(In the formula, L, ^A1 , ^A2 , ^Y1 , ^Y2 , ^P1 , ^Q1 , ^T1 , R, ^X1 , ^Z1a , ^Z2a , Cou, E, ^G1 , ^G2 , n1 and the dashed line are the same as above.)

（式中、ｎ１、Ｌ、Ｑ¹、Ｘ¹、Ｒ及び破線は、上記と同じ。） 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).

(In the formula, n1, L, Q ¹ , X ¹ , R and the dashed line are the same as above.)

（式中、Ｌ、Ａ²、Ｑ¹、Ｔ¹、Ｒ及び破線は、上記と同じ。） The side chain represented by formula (a2-1) is preferably a side chain represented by the following formula (a2-1-1).

(In the formula, L, ^A2 , ^Q1 , ^T1 , R and the dashed line are the same as above.)

（式中、Ｌ、Ｃｏｕ及び破線は、上記と同じ。） 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).

(In the formula, L, Cou and the dashed line are the same as above.)

（式中、Ｌ、Ｒ及び破線は、上記と同じ。） The side chain represented by formula (a4-1) is preferably a side chain represented by the following formula (a4-1-1), (a4-1-2), (a4-1-3) or (a4-1-4).

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

（式中、Ｌ、Ｒ及び破線は、上記と同じ。） 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.)

（式中、Ｌ、Ｒ及び破線は、上記と同じ。） 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).

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

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

(A) The side chain polymer preferably reacts to light in the wavelength range of 250 to 400 nm and exhibits liquid crystallinity in the temperature range of 100 to 300°C. (A) The side chain polymer preferably has a photosensitive side chain that reacts to light in the wavelength range of 250 to 400 nm.

(A) Side-chain polymers have photosensitive side chains bonded to their main chains, and can undergo crosslinking or isomerization reactions in response to light. The structure of the photosensitive side-chain polymer capable of expressing liquid crystallinity is not particularly limited as long as it satisfies such characteristics, but it is preferable for the side-chain structure to have a rigid mesogen component. When the above-mentioned side-chain polymer is used as a single-layer retardation material, stable optical anisotropy can be obtained.

A more specific example of a photosensitive side-chain polymer structure capable of exhibiting liquid crystallinity is preferably a structure having a main chain composed 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.

（式中、Ｒ¹は、炭素数１～３０のアルキレン基であり、該アルキレン基の１つ又は複数の水素原子が、フッ素原子又は有機基で置換されていてもよい。また、Ｒ¹中の－ＣＨ₂ＣＨ₂－が、－ＣＨ＝ＣＨ－で置換されていてもよく、Ｒ¹中の－ＣＨ₂－が、－Ｏ－、－ＮＨ－Ｃ（＝Ｏ）－、－Ｃ（＝Ｏ）－ＮＨ－、－Ｃ（＝Ｏ）－Ｏ－、－Ｏ－Ｃ（＝Ｏ）－、－ＮＨ－、－ＮＨ－Ｃ（＝Ｏ）－ＮＨ－及び－Ｃ（＝Ｏ）－からなる群から選ばれる基で置換されていてもよい。ただし、隣接する－ＣＨ₂－が同時にこれらの基で置換されることはない。
　Ｒ⁴は、芳香族基、多環芳香族基、脂環族基、フェニルシクロヘキシル基、複素環式基又は縮合環式基である。
　Ｒ⁵は、－ＣＨ₂－、－Ｏ－、－ＮＨ－、－Ｃ（＝Ｏ）－、－Ｃ（＝Ｏ）－Ｏ－、－Ｏ－Ｃ（＝Ｏ）－、－ＣＨ＝ＣＨ－Ｃ（＝Ｏ）－Ｏ－、－Ｃ（＝Ｏ）－ＮＨ－、－ＮＨ－Ｃ（＝Ｏ）－又は－ＮＨ－Ｃ（＝Ｏ）－ＮＨ－である。
　Ｒ⁶は、炭素数１～１０のアルキレン基であり、該アルキレン基の１つ又は複数の水素原子が、フッ素原子又は有機基で置換されていてもよい。また、Ｒ⁶中の－ＣＨ₂－が、－Ｏ－、－ＮＨ－及び－Ｃ（＝Ｏ）－からなる群から選ばれる基で置換されていてもよい。隣接する－ＣＨ₂－が同時にこれらの基で置換されていてもよい。
　式（ｂ）中の環構造中の水素原子は、炭素数１～６のアルキル基、炭素数１～６のハロアルキル基、炭素数１～６のアルコキシ基、炭素数１～６のハロアルコキシ基、ハロゲン基、シアノ基及びニトロ基から選ばれる置換基で置換されていてもよい。
　ｄは、０、１又は２である。
　ｅは、０又は１である。
　ｆは、０又は１である。
　破線は、結合手である。） The polymer (A) has a side chain having a non-photoreactive hydrogen-bonding functional group as well as a side chain having a photo-alignable moiety represented by the above formula (a). The side chain having a non-photoreactive hydrogen-bonding functional group preferably has a side chain b, which is a carboxylic acid side chain represented by the following formula (b).

(In the formula, R ¹ is 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 an organic group. Furthermore, -CH ₂ CH ₂ - in R ¹ may be substituted with -CH=CH-, and -CH ₂ - in R ¹ may be substituted with a group selected from the group consisting of -O-, -NH-C(=O)-, -C(=O)-NH-, -C(=O)-O-, -O-C(=O)-, -NH-, -NH-C(=O)-NH- and -C(=O)-. However, adjacent -CH ₂ -'s are not substituted with these groups at the same time.
^R4 is an aromatic group, a polycyclic aromatic group, an alicyclic group, a phenylcyclohexyl group, a heterocyclic group, or a fused ring group.
^R5 is _-CH2- , -O-, -NH-, -C(=O)-, -C(=O)-O-, -O-C(=O)-, -CH=CH-C(=O)-O-, -C(=O)-NH-, -NH-C(=O)- or -NH-C(=O)-NH-.
R ⁶ 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. In addition, -CH ₂ - in R ⁶ may be substituted with a group selected from the group consisting of -O-, -NH-, and -C(═O)-. Adjacent -CH ₂ - may also be substituted with these groups at the same time.
A 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, 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 group, 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 lines represent bonds.)

The number of ring structures in the side chain represented by the above formula (b) is preferably 3 or less. Here, the ring structure of a condensed ring is counted as one. That is, there is one ring structure in a phenylene group or naphthylene group, and there are two ring structures in a biphenylylene group or cyclohexanediyl group.

　式（ｂ１）中、Ｒ¹、Ｒ⁴～Ｒ⁶、ｄ及びｆは、上記と同じ。式（ｂ１）中の環構造は３個以下である。式（ｂ１）中のベンゼン環中の水素原子は、炭素数１～６のアルキル基、炭素数１～６のハロアルキル基、炭素数１～６のアルコキシ基、炭素数１～６のハロアルコキシ基、ハロゲン基、シアノ基及びニトロ基から選ばれる置換基で置換されていてもよい。破線は、結合手である。 The side chain b is preferably, for example, one represented by the following formula (b1).

In formula (b1), R ¹ , R ⁴ to R ⁶ , d and f are the same as above. The number of ring structures in formula (b1) is 3 or less. The 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, 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 group, a cyano group and a nitro group. The dashed lines represent bonds.

The (A) side chain type polymer exhibits liquid crystallinity in the temperature range of 100 to 300°C, and can further have a side chain that only exhibits 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 only exhibits liquid crystallinity during the process for producing the retardation material of the present invention (i.e., steps (I) to (III) described below).

（式（１）～（６）中、Ａ¹、Ａ²はそれぞれ独立に、単結合、－Ｏ－、－ＣＨ₂－、－Ｃ（＝Ｏ）－Ｏ－、－Ｏ－Ｃ（＝Ｏ）－、－Ｃ（＝Ｏ）－ＮＨ－又は－ＮＨ－Ｃ（＝Ｏ）－である。Ｒ¹¹は、－ＮＯ₂、－ＣＮ、ハロゲン原子、フェニル基、ナフチル基、ビフェニリル基、フラニル基、１価窒素含有複素環基、炭素数５～８の１価脂環式炭化水素基、炭素数１～１２のアルキル基又は炭素数１～１２のアルキルオキシ基である。Ｒ¹²は、フェニル基、ナフチル基、ビフェニリル基、フラニル基、１価窒素含有複素環基、炭素数５～８の１価脂環式炭化水素基、及びこれらを組み合わせて得られる基からなる群から選ばれる基であり、これらに結合する水素原子が、－ＮＯ₂、－ＣＮ、ハロゲン原子、炭素数１～５のアルキル基又は炭素数１～５のアルコキシ基で置換されてもよい。Ｒ¹³は、水素原子、－ＮＯ₂、－ＣＮ、ハロゲン原子、フェニル基、ナフチル基、ビフェニリル基、フラニル基、１価窒素含有複素環基、炭素数５～８の１価脂環式炭化水素基、炭素数１～１２のアルキル基又は炭素数１～１２のアルコキシ基である。Ｅ¹は、－Ｃ（＝Ｏ）－Ｏ－又は－Ｏ－Ｃ（＝Ｏ）－である。ｄは、１～１２の整数である。ｋ１～ｋ５は、それぞれ独立に、０～２の整数であるが、ｋ１～ｋ５の合計は２以上である。ｋ６及びｋ７は、それぞれ独立に、０～２の整数であるが、ｋ６及びｋ７の合計は１以上である。ｍ１、ｍ２は、それぞれ独立に、１～３の整数である。ｎは、０又は１である。Ｚ¹及びＺ²は、それぞれ独立に、単結合、－Ｃ（＝Ｏ）－、－ＣＨ₂Ｏ－又は－ＣＦ₂－である。破線は、結合手である。） The side chain c is preferably any one or two liquid crystalline side chains selected from the group consisting of the following formulae (1) to (6).

In formulae (1) to (6), A ¹ and A ² are each independently a single bond, -O-, -CH ₂ -, -C(═O)-O-, -O-C(═O)-, -C(═O)-NH-, or -NH-C(═O)-. R ¹¹ is -NO ₂ , -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. R 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 groups, and a hydrogen atom bonded to these is -NO ₂ , -CN, a halogen atom, an alkyl group having 1 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms. R ¹³ is a hydrogen atom, -NO ₂ , -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. E 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, but the sum of k1 to k5 is 2 or more. k6 and k7 are each independently an integer of 0 to 2, but 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 Each of ² is independently a single bond, -C(=O)-, _-CH2O- or _-CF2- . The dashed lines represent bonds.

The side chain type polymer (A) has a self-crosslinking moiety. Examples of the self-crosslinking moiety include trialkoxysilyl groups, blocked isocyanate groups, epoxy groups, oxetane groups, groups having an oxazoline ring, N-alkoxymethylamide groups, N-hydroxymethylamide groups, and vinyl groups. These side chains having self-crosslinking moieties (hereinafter also referred to as side chain d) react with each other or with the COOH groups and OH groups of the polymer, which is component (A), to form a crosslinked structure. As a result, the strength of the resulting retardation material can be increased.

Examples of the combination of the side chain having a photoreactive moiety (side chain a) and the side chain having a self-crosslinking moiety (side chain d) that the side chain type polymer (A) has are as follows:
a side chain having a photoreactive site and a hydrogen-bonding functional group, and a side chain having a trialkoxysilyl group; a side chain having a photoreactive site and a hydrogen-bonding functional group, and a side chain having a blocked isocyanate group; a side chain having a photoreactive site and a hydrogen-bonding functional group, and a side chain having an epoxy group; a side chain having a photoreactive site and a hydrogen-bonding functional group, and a side chain having an oxetane group; a side chain having a photoreactive site and a hydrogen-bonding functional group, and a side chain having an oxazoline ring; a side chain having a photoreactive site and a hydrogen-bonding functional group, and a side chain having an N-alkoxymethylamide group; a side chain having a photoreactive site and a hydrogen-bonding functional group, and a side chain having an N-hydroxymethylamide group; a side chain having a photoreactive site and a hydrogen-bonding functional group, and a side chain having a vinyl group;
a side chain having a photoreactive site, a non-hydrogen-bonding functional group at its terminal, and a side chain having a trialkoxysilyl group; a side chain having a photoreactive site, a non-hydrogen-bonding functional group at its terminal, and a blocked isocyanate group; a side chain having a photoreactive site, a non-hydrogen-bonding functional group at its terminal, and a side chain having an epoxy group; a side chain having a photoreactive site, a non-hydrogen-bonding functional group at its terminal, and a side chain having an oxetane group; a side chain having a photoreactive site, a non-hydrogen-bonding functional group at its terminal, and a side chain having an oxazoline ring; a side chain having a photoreactive site, a non-hydrogen-bonding functional group at its terminal, and a side chain having an N-alkoxymethylamide group; a side chain having a photoreactive site, a non-hydrogen-bonding functional group at its terminal, and a N-hydroxymethylamide group; a side chain having a photoreactive site, a non-hydrogen-bonding functional group at its terminal, and a side chain having a vinyl group.

(A) The side chain type polymer may have a side chain having a hydroxyalkyl group (hereinafter also referred to as side chain e). The side chain having a hydroxyalkyl group has an alcoholic hydroxy group, and thus can induce a crosslinking reaction with side chain d when the self-crosslinking site of side chain d is an N-alkoxymethylamide site or an N-hydroxymethylamide site.

The side chain polymer used in the present invention has a photosensitive side chain bonded to the main chain, and can undergo a crosslinking reaction, isomerization reaction, or Fries rearrangement in response to optimal light selected from a wavelength range of 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 such characteristics, but it is preferable for the side chain structure to have a rigid mesogen component. When the above side chain polymer is made into a single-layer retardation film, stable optical anisotropy can be obtained.

A more specific example of the structure of the photosensitive side chain type polymer is preferably a structure having a main chain composed 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.

The side chain 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, a monomer that provides side chain d, and, if necessary, a monomer that provides side chain c and a monomer that provides side chain e.

（式中、ＰＧは、重合性基であり、Ａ¹、Ａ²、Ｄ¹、Ｌ、Ｔ¹、Ｙ¹、Ｙ²、Ｐ¹、Ｑ¹、Ｑ²、Ｒ、Ｃｏｕ、Ｅ、Ｘ¹、Ｘ²、Ｚ^1a、Ｚ^2a、Ｇ¹、Ｇ²、ｎ１及びｎ２は、上記と同じ。） 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).

(In the formula, PG is a polymerizable group, and ^A1 , ^A2 , ^D1 , L, ^T1 , ^Y1 , ^Y2 , ^P1 , ^Q1 , ^Q2 , R, Cou, E, ^X1 , ^X2 , ^Z1a , ^Z2a , ^G1 , ^G2 , n1 and n2 are the same as above.)

（式中、Ｒ^Aは、水素原子又はメチル基であり、破線は、Ｌとの結合手である。） In formulae (M1-1), (M1-2), (M2), (M3), (M4), (M5) and (M6), PG is a polymerizable group, and is preferably a group represented by any one of the following formulae (PG1) to (PG8). Of these, from the viewpoint of ease of control of the polymerization reaction and stability of the polymer, an acrylic or methacrylic group represented by formula (PG1) is preferred.

(In the formula, ^R is a hydrogen atom or a methyl group, and the dashed line is a bond to L.)

（式中、ＰＧ、Ｌ、Ｑ¹、Ｘ¹、Ｙ¹、Ｚ^1a、Ｚ^2a、Ｐ¹及びＲは、上記と同じ。） 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).

(In the formula, PG, L, ^Q1 , ^X1 , ^Y1 , ^Z1a , ^Z2a , ^P1 and R are the same as above.)

（式中、ＰＧ、Ａ²、Ｌ、Ｔ¹、Ｙ¹、Ｚ^1a、Ｚ^2a、Ｐ¹、Ｑ¹及びＲは、上記と同じ。） The compound represented by formula (M2) is preferably one represented by the following formula (M2-1).

(In the formula, PG, ^A2 , L, ^T1 , ^Y1 , ^Z1a , ^Z2a , ^P1 , ^Q1 and R are the same as above.)

（式中、ＰＧ、Ａ¹、Ｌ、Ｘ¹、Ｑ¹、Ｃｏｕ及びｎ１は、上記と同じ。） The compound represented by formula (M3) is preferably one represented by the following formula (M3-1).

(In the formula, PG, A ¹ , L, X ¹ , Q ¹ , Cou and n1 are the same as above.)

（式中、ＰＧ、Ａ¹、Ｌ、Ｘ¹、Ｙ¹、Ｙ²、Ｑ¹、Ｅ、Ｒ及びｎ１は、上記と同じ。） The compound represented by formula (M4) is preferably one represented by the following formula (M4-1).

(In the formula, PG, ^A1 , L, ^X1 , ^Y1 , ^Y2 , ^Q1 , E, R and n1 are the same as above.)

（式中、ＰＧ、Ａ¹、Ｌ、Ｘ¹、Ｙ¹、Ｙ²、Ｑ¹、Ｒ及びｎ１は、上記と同じ。） The compound represented by formula (M5) is preferably one represented by the following formula (M5-1).

(In the formula, PG, ^A1 , L, ^X1 , ^Y1 , ^Y2 , ^Q1 , R and n1 are the same as above.)

（式中、ＰＧ、Ａ¹、Ｌ、Ｘ¹、Ｙ¹、Ｙ²、Ｑ¹、Ｇ¹、Ｇ²、Ｒ及びｎ１は、上記と同じ。） The compound represented by formula (M6) is preferably one represented by the following formula (M6-1).

(In the formula, PG, ^A1 , L, ^X1 , ^Y1 , ^Y2 , ^Q1 , ^G1 , ^G2 , R and n1 are the same as above.)

（式中、ＰＧ、ｎ１、Ｌ、Ｑ¹、Ｘ¹及びＲは、上記と同じ。） 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).

(In the formula, PG, n1, L, ^Q1 , ^X1 and R are the same as above.)

（式中、ＰＧ、Ａ²、Ｌ、Ｔ¹、Ｑ¹及びＲは、上記と同じ。） The compound represented by formula (M2-1) is preferably one represented by the following formula (M2-2).

(In the formula, PG, ^A2 , L, ^T1 , ^Q1 and R are the same as above.)

（式中、ＰＧ、Ｌ及びＣｏｕは、上記と同じ。） The compound represented by formula (M3-1) is preferably one represented by the following formula (M3-2), (M3-3) or (M3-4).

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

（式中、ＰＧ、Ｌ及びＲは、上記と同じ。） The compound represented by formula (M4-1) is preferably one represented by the following formula (M4-2), (M4-3), (M4-4) or (M4-5).

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

（式中、ＰＧ、Ｌ及びＲは、上記と同じ。） The compound represented by formula (M5-1) is preferably one represented by the following formula (M5-2) or (M5-3).

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

（式中、ＰＧ、Ｌ及びＲは、上記と同じ。） The compound represented by formula (M6-1) is preferably one represented by the following formula (M6-2), (M6-3), or (M6-4).

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

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, s1 represents the number of methylene groups and is an integer of 2 to 9, R ¹¹ is -H, -CH ₃ , -OCH ₃ , -C(CH ₃ ) ₃ , -C(═O)-CH ₃ or -CN, and R ¹² is -H, -CH ₃ , -OCH ₃ , -CN or -F.

Examples of the compound represented by formula (M1-2) include those represented by any of the following formulae (A-1-2-1) to (A-1-2-4): In the following formulae, PG is a polymerizable group, and s1 is the same as above.

Specific examples of compounds 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.

Examples of compounds represented by formula (M2) include those represented by any of the following formulas (A-2-1) to (A-2-9). In the following formulas (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. R ²¹ is -CH ₃ , -OCH ₃ , -C(CH ₃ ) ₃ , -C(═O)-CH ₃ , -CN or -F.

Examples of the compound represented by formula (M3) include those represented by any of the following formulae (A-3-1) to (A-3-5): In the following formulae, PG is a polymerizable group, and s1 is the same as above.

Examples of the compound represented by formula (M4) include those represented by any of the following formulae (A-4-1) to (A-4-4): In the following formula, PG is a polymerizable group, and s1 is the same as above.

Examples of the compound represented by formula (M5) include those represented by any of the following formulae (A-5-1) to (A-5-3): In the following formula, PG is a polymerizable group, and s1 is the same as above.

Examples of the compound represented by formula (M6) include those represented by any of the following formulae (A-6-1) to (A-6-3): In the following formula, PG is a polymerizable group, and s1 is the same as above.

Some of the above monomers are commercially available, and others can be produced by methods described, for example, in WO 2015/002292.

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

（式中、ＰＧは、上記（ＰＧ１）～（ＰＧ５）のいずれかであり、ｐは、２～９の整数である。） Preferred examples of such monomers include those represented by the following formulas (M1-2-a1) to (M1-2-a6).

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

（式中、ＰＧは、上記（ＰＧ１）～（ＰＧ５）のいずれかであり、Ｒ¹、Ｒ⁴～Ｒ⁶、ｄ、ｅ及びｆは、上記と同じ。式中の環構造中の水素原子は、炭素数１～６のアルキル基、炭素数１～６のハロアルキル基、炭素数１～６のアルコキシ基、炭素数１～６のハロアルコキシ基、ハロゲン基、シアノ基及びニトロ基から選ばれる置換基で置換されていてもよい。） Examples of the monomer having the structure represented by formula (b) (hereinafter also referred to as monomer MB) include a compound represented by the following formula (MB1).

(In the formula, PG is any one of the above (PG1) to (PG5), and R ¹ , R ⁴ to R ⁶ , 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, 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 group, a cyano group and a nitro group.)

（式中、ＰＧ、Ｒ¹、Ｒ⁴～Ｒ⁶、ｄ及びｆは、上記と同じ。式中のベンゼン環中の水素原子は、炭素数１～６のアルキル基、炭素数１～６のハロアルキル基、炭素数１～６のアルコキシ基、炭素数１～６のハロアルコキシ基、ハロゲン基、シアノ基及びニトロ基から選ばれる置換基で置換されていてもよい。） The monomer MB is preferably one represented by the following formula (MB1A).

(In the formula, PG, R ¹ , R ⁴ to R ⁶ , d 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, 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 group, a cyano group and a nitro group.)

　（式中、ＰＧは、上記（ＰＧ１）～（ＰＧ５）のいずれかであり、ｐは、２～９の整数である。） As the monomer MB1A, the monomers represented by the following MB1A-1 to MB1A-8 are preferred.

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

Some of these monomers are commercially available, and others can be produced from known substances using known production methods.

In the above formulas (MB1A-1) to (MB1A-8), PG is preferably an acrylic or methacrylic group represented by formula (PG1) from the viewpoint of ease of control of the polymerization reaction and the stability of the polymer, and is more preferably an acrylic group from the viewpoint of crack resistance.

A monomer having a structure that only expresses liquid crystallinity in side chain c (hereinafter also referred to as monomer MC) is a monomer that allows a polymer derived from the monomer to express liquid crystallinity.

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

More specific examples of monomer MC include those having a polymerizable group derived from at least one selected from the group consisting of radical polymerizable groups such as hydrocarbons, (meth)acrylates, itaconates, fumarates, maleates, α-methylene-γ-butyrolactone, styrene, vinyl, maleimides, and norbornenes, and siloxanes, and a structure consisting of at least one of the above formulas (c1) to (c10). In particular, monomer MC is preferably one having (meth)acrylate as the polymerizable group.

　（式中、ＰＧは、上記（ＰＧ１）～（ＰＧ５）のいずれかであり、ｐは、２～９の整数である。） Preferred examples of the monomer MC include those represented by the following formulae (MC-1) to (MC-6).

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

Examples of monomers having a self-crosslinking site in the side chain d (hereinafter also referred to as monomer MD) include (meth)acrylamide compounds substituted with a hydroxymethyl group or an alkoxymethyl group, such as N-hydroxymethyl(meth)acrylamide, N-methoxymethyl(meth)acrylamide, N-ethoxymethyl(meth)acrylamide, and N-butoxymethyl(meth)acrylamide; monomers having a trialkoxysilyl group, such as 3-trimethoxysilylpropyl acrylate, 3-triethoxysilylpropyl acrylate, 3-trimethoxysilylpropyl methacrylate, and 3-triethoxysilylpropyl methacrylate; glycidyl acrylate, glycidyl monomers having a glycidyl group or an epoxycyclohexyl group, such as dimethyl methacrylate and 3,4-epoxycyclohexylmethyl methacrylate; monomers having a vinyl group, such as allyl acrylate and allyl methacrylate; monomers having a blocked isocyanate group, such as 2-(0-(1'-methylpropylideneamino)carboxyamino)ethyl methacrylate and 2-(3,5-dimethylpyrazolyl)carbonylamino)ethyl methacrylate; monomers containing an oxazoline ring, such as 2-vinyl-2-oxazoline and 2-isopropenyl-2-oxazoline; and monomers having an oxetane group, such as (3-ethyloxetan-3-yl)methyl methacrylate. Note that (meth)acrylamide means both acrylamide and methacrylamide.

Examples of monomers that provide side chain e (hereinafter also referred to as monomer ME) include 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 3-hydroxypropyl acrylate, 3-hydroxypropyl methacrylate, 4-hydroxybutyl acrylate, 4-hydroxybutyl methacrylate, 6-hydroxyhexyl acrylate, 6-hydroxyhexyl methacrylate, 8-hydroxyoctyl acrylate, 8-hydroxyoctyl methacrylate, 12-hydroxydodecyl acrylate, 12-hydroxydodecyl methacrylate, 2,3-dihydroxypropyl ... Examples of the acryloyloxypropyl methacrylate include diethylene glycol monoacrylate, diethylene glycol monomethacrylate, caprolactone 2-(acryloyloxy)ethyl ester, caprolactone 2-(methacryloyloxy)ethyl ester, poly(ethylene glycol) ethyl ether acrylate, poly(ethylene glycol) ethyl ether methacrylate, 5-acryloyloxy-6-hydroxynorbornene-2-carboxylic-6-lactone, 5-methacryloyloxy-6-hydroxynorbornene-2-carboxylic-6-lactone(4-(hydroxymethyl)cyclohexyl)methyl acrylate, and compounds represented by the following formulae (ME-a1) to (ME-a3).

In addition, a monomer MF can be copolymerized as a non-liquid crystal side chain f to the extent that the photoreactivity and/or liquid crystallinity is not impaired. Examples of the monomer MF include industrially available monomers capable of radical polymerization reactions. 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.

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

Examples of acrylic acid ester compounds include methyl acrylate, ethyl acrylate, isopropyl acrylate, benzyl acrylate, naphthyl acrylate, anthryl acrylate, anthryl methyl 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-ethyl-2-adamantyl acrylate, and tetrahydrodicyclopentadienyl acrylate.

Examples of methacrylic acid ester compounds include methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, benzyl methacrylate, naphthyl methacrylate, anthryl methacrylate, anthryl methyl 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-ethyl-2-adamantyl methacrylate, tetrahydrodicyclopentadienyl methacrylate, and 2-(methacryloyloxy)ethyl isonicotinate.

Examples of maleimide compounds include N-benzylmaleimide, 4-maleimidobutyric acid, N-methoxycarbonylmaleimide, and N-cyclohexylmaleimide.

Examples of styrene compounds include styrene, 4-methylstyrene, 4-vinylphenylboronic acid, 4-vinylbenzoic acid, trans-anethole, and 4-vinylpyridine.

Examples of vinyl compounds include vinyl ether, methyl vinyl ether, benzyl vinyl ether, phenyl vinyl ether, and propyl vinyl ether.

Examples of acrylamide compounds include acrylamide, N,N-dimethylacrylamide, N-isopropylacrylamide, N-propylacrylamide, and N-tert-butylacrylamide.

Examples of methacrylamide compounds include N-methylmethacrylamide, N,N-dimethylmethacrylamide, and N-(4-hydroxyphenyl)methacrylamide.

The content of side chain a in the side chain type 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. From the viewpoint of light resistance, 5 to 30 mol % is preferable.

The content of side chain b in the side chain type polymer of the present invention is preferably 10 to 95 mol % from the viewpoint of retardation value.

The content of side chain d in the side chain type polymer of the present invention is preferably 1 to 30 mol %, more preferably 1 to 20 mol %, from the viewpoint of increasing the strength of the film while not impairing the liquid crystallinity of the polymer.

As described above, the side chain polymer of the present invention may contain side chain e. When the side chain polymer of the present invention contains side chain e, the content of side chain e is preferably 1 to 20 mol %, and more preferably 1 to 15 mol %, from the viewpoint of liquid crystallinity.

The content of side chain c in the side chain type polymer of the present invention is the remaining portion when the total content of side chain a, side chain b, side chain d, and side chain e is less than 100 mol %.

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

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, it can be produced by radical polymerization, cationic polymerization, or anionic polymerization using the above-mentioned monomer MA, monomer MB, and optionally monomer MC, monomer MD, and optionally monomer ME, and optionally monomer MF. Of these, radical polymerization is particularly preferred from the viewpoint of ease of reaction control, etc.

As a 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.

A radical thermal polymerization initiator is a compound that generates radicals when heated to a temperature above 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.), etc. Radical thermal polymerization initiators may be used alone or in combination of two or more.

The radical photopolymerization initiator is not particularly limited as long as it is a compound that initiates radical polymerization by irradiation with light. 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-hydroxycyclohexyl phenyl ketone, and isopropyl benzoin ether. , isobutyl benzoin ether, 2,2-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, 4-dimethylaminobenzoic acid isoamyl, 4,4'-di(tert-butylperoxycarbonyl) 1,4'-dimethoxystyryl)-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',4'-dimethoxystyryl)-4,6-bis(trichloromethyl)-s-triazine, 2-(2',4'-dimethoxystyryl)-4,6-bis(trichloromethyl)-s-triazine, 2-(2',4'-dimethoxystyryl)-4,6-bis(trichloromethyl)-s-triazine, -(2'-methoxystyryl)-4,6-bis(trichloromethyl)-s-triazine, 2-(4'-pentyloxystyryl)-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-cyclopentadiene-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, Examples of the radical photopolymerization initiator include 3,4'-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. The radical photopolymerization initiator may be used alone or in combination of two or more.

The radical polymerization method is not particularly limited, and emulsion polymerization, suspension polymerization, dispersion polymerization, precipitation polymerization, bulk polymerization, solution polymerization, etc. can be used.

The organic solvent used in the polymerization reaction is not particularly limited as long as it dissolves the produced polymer. Specific examples 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 a acetate, ethyl cellosolve acetate, butyl carbitol, ethyl carbitol, ethylene glycol, ethylene glycol monoacetate, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, propylene glycol, propylene 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, 1,4-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, 3-butoxy-N,N-dimethylpropanamide, etc.

The above organic solvents may be used alone or in combination of two or more. Furthermore, even if the solvent does not dissolve the polymer produced, it may be mixed with the above organic solvent to the extent that the polymer produced does not precipitate. In addition, since oxygen in the organic solvent in radical polymerization inhibits the polymerization reaction, it is preferable to use an organic solvent that has been degassed to the extent possible.

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 polymer with a high molecular weight, and if the concentration is too high the viscosity of the reaction liquid becomes too high, making uniform stirring difficult, so 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 in the early stages, and then an organic solvent can be added.

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

To recover the polymers produced from the reaction solution obtained by the above reaction, the reaction solution may be poured into a poor solvent to precipitate the polymers. 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 normal or reduced pressure. The recovered polymer can be redissolved in an organic solvent and the reprecipitation recovery operation repeated 2 to 10 times to reduce the amount of impurities in the polymer. Examples of poor solvents include alcohols, ketones, and hydrocarbons. It is preferable to use three or more poor solvents selected from these because this further increases the efficiency of purification.

In consideration of the strength of the resulting coating film, the workability during coating film formation, and the uniformity of the coating film, the side chain polymer (A) of the present invention preferably has a weight average molecular weight measured by GPC (Gel Permeation Chromatography) of 2,000 to 2,000,000, more preferably 2,000 to 1,000,000, and even more preferably 5,000 to 200,000.

[(B) Organic Solvent]
The polymer composition used in the present invention contains an organic solvent (good solvent). The 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, dimethylsulfoxide, tetramethylurea, pyridine, dimethylsulfone, hexamethylphosphoramide, γ-butyrolactone, 3-methoxy-N,N-dimethylpropanamide, 3-ethoxy-N,N-dimethylpropanamide, 3-butoxy-N, Examples of the amines include 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, 1-methoxy-2-propanol, and 1,3-dioxolane. These may be used alone or in combination of two or more.

The polymer composition used in the present invention may also contain a solvent (poor solvent) that improves the film thickness uniformity and surface smoothness when the polymer composition is applied.

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-tert-butyl ether, dipropylene glycol monomethyl ether, diethylene glycol, diethylene glycol monoacetate butyl ether, 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, di Hexyl ether, 1-hexanol, n-hexane, n-pentane, n-octane, diethyl ether, methyl lactate, ethyl lactate, n-propyl lactate, n-butyl lactate, isoamyl lactate, methyl acetate, ethyl acetate, propyl acetate, n-butyl acetate, amyl acetate, propylene glycol acetate monoethyl ether, 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-ethoxy-2-propanol, 1-butoxy-2-propanol, 1-phenoxy-2-propanol, propylene glycol Examples of solvents include ethanol, propylene glycol diacetate, propylene glycol-1-monomethyl ether-2-acetate, propylene glycol-1-monoethyl ether-2-acetate, dipropylene glycol, 2-(2-ethoxypropoxy)propanol, water, anisole, n-hexane, n-pentane, n-octane, cyclopentyl methyl ether, propyl ether, diisopropyl ether, ethyl isobutyl ether, butyl ether, diisobutyl ketone, methyl isobutyl ketone, 1,4-cineole, 1,8-cineole, tetrahydrofurfuryl propionate, 2,2-di(2-tetrahydrofuryl)propane, and 2,5-dimethoxytetrahydrofuran. Examples of solvents having low surface tension include ethanol, propylene glycol diacetate ...

The poor solvent may be used alone or in combination of two or more. 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.

[Other ingredients]
The polymer composition used in the present invention may contain components other than (A) and (B). Examples of the components include, but are not limited to, a compound that accelerates a crosslinking reaction, a compound that improves the film thickness uniformity and surface smoothness when the polymer composition is applied, and a compound that improves the adhesion between the retardation material and the substrate.

Compounds that promote the crosslinking reaction include acid catalysts (acid, thermal acid generator, photoacid generator), base catalysts (base, thermal base generator, photobase generator), and radical initiators that are activated by heat or light. Examples of acid catalysts include sulfonic acids such as hydrochloric acid, methanesulfonic acid, ethanesulfonic acid, p-toluenesulfonic acid, camphorsulfonic acid, and ethanedisulfonic acid, as well as their hydrates and salts. Examples of base catalysts include bases such as pyridine, 4-dimethylaminopyridine, and imidazole, as well as their hydrates and salts. Examples of thermal radical initiators include peroxide compounds, persulfates, and azo compounds. There are no particular limitations on the radical photopolymerization initiator, so long as it is a compound that initiates radical polymerization by irradiation with light. Examples of such radical photopolymerization initiators include benzophenone, Michler's ketone, and 4,4'-bis(diethylamino)benzophenone.

The content of the compound that promotes the crosslinking reaction used in the present invention is preferably 0.01 to 10 parts by mass, more preferably 0.05 to 8 parts by mass, and even more preferably 0.1 to 6 parts by mass, per 100 parts by mass of the polymer (A), which is component (A).

Compounds that improve film thickness uniformity and surface smoothness include fluorine-based surfactants, silicone-based surfactants, nonionic surfactants, etc. Specific examples of these include EFTOP (registered trademark) 301, EF303, EF352 (manufactured by Tochem Products), MEGAFAC (registered trademark) F171, F173, F560, F563, R-30, R-40, R-41 (manufactured by DIC Corporation), Fluorad FC430, FC431 (manufactured by 3M), 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.), BYK302, BYK331, BYK348, BYK360N, BYK381, BYK3441, and the like. The content of these surfactants is preferably 0.01 to 5 parts by mass, more preferably 0.01 to 3 parts by mass, and even more preferably 0.01 to 1 part by mass, per 100 parts by mass of component (A).

Specific examples of compounds that improve adhesion between the retardation material and the substrate include functional silane-containing compounds.

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-based compound or an epoxy group-containing compound may be added to the polymer composition.

When a compound that improves adhesion to the substrate is used, the content is preferably 0.1 to 30 parts by mass, and 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 parts by mass, the effect of improving adhesion cannot be expected, and if it is more than 30 parts by mass, the alignment of the liquid crystal may deteriorate.

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

In addition to the above, the polymer composition used in the present invention may contain dielectric or conductive substances for the purpose of changing the electrical properties of the phase difference material, such as the dielectric constant or conductivity, and may also contain crosslinking compounds for the purpose of increasing the hardness and density of the film when made into a phase difference material, as long as the effects of the present invention are not impaired.

[Preparation of polymer composition]
The polymer composition used in the present invention is preferably prepared as a coating solution 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 compound that promotes the crosslinking reaction described above, the solvent or compound that improves the film thickness uniformity and surface smoothness, the compound that improves the adhesion between the liquid crystal alignment film and the substrate, etc. are dissolved in the organic solvent of the component (B). Here, the content of the component (A) is preferably 1 to 30% by mass in the composition of the present invention, more preferably 5 to 30% by mass.

The polymer composition used in the present invention may contain other polymers in addition to the polymer of component (A) to the extent that the liquid crystal expression ability and photosensitive performance 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 expressing liquid crystallinity, such as poly(meth)acrylate, polyamic acid, and polyimide.

[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) 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.

[Step (I)]
Step (I) is a step of applying the polymer composition used in the present invention onto a substrate to form a coating film. More specifically, the composition is applied onto a substrate (e.g., a silicon/silicon dioxide-coated substrate, a silicon nitride substrate, a 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 triacetyl cellulose (TAC) film, a cycloolefin polymer film, a polyethylene terephthalate film, an acrylic film, or other resin 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 30 to 200°C, preferably 40 to 150°C, by a heating means such as a hot plate, a heat circulation type oven, or an IR (infrared) type oven, to obtain a coating film.

[Step (II)]
In step (II), the coating film obtained in step (I) is irradiated with polarized ultraviolet light. When irradiating the film surface of the coating film with polarized ultraviolet light, the polarized ultraviolet light is irradiated from a certain direction relative to the substrate through 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.

The amount of polarized UV light to be irradiated depends on the coating film used. The amount of irradiation is preferably within the range of 1 to 70%, and more preferably within the 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.

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

The heating can be performed using a heating means such as a hot plate, a hot air circulation oven, or an IR (infrared) oven. The heating temperature can be determined taking into consideration the temperature at which the liquid crystallinity of the coating film to be used is expressed.

The heating temperature is preferably within the temperature range at which the polymer of component (A) contained in the composition used in the present invention exhibits liquid crystallinity (hereinafter referred to as the liquid crystal appearance temperature). In the case of a thin film surface such as a coating film, the liquid crystal appearance temperature of the coating film surface is expected to be lower than the liquid crystal appearance temperature when the polymer of component (A) is observed in bulk. For this reason, it is more preferable that the heating temperature is within the temperature range of the liquid crystal appearance temperature of the coating film surface. In other words, the temperature range of the heating temperature after irradiation with polarized ultraviolet light is preferably a temperature range with a lower limit of a temperature 10°C lower than the lower limit of the temperature range of the liquid crystal appearance temperature of the polymer of component (A) and an upper limit of a temperature 10°C lower than the upper limit of the liquid crystal temperature range. If the heating temperature is lower than the above temperature range, the effect of amplifying the anisotropy by heat in the coating film tends to be insufficient, and if the heating temperature is too high, the state of the coating film tends to become closer to an isotropic liquid state (isotropic phase), in which case it may be difficult to realign in one direction by self-organization.

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

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

The single-layer retardation material of the present invention obtained in this manner has 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 retardation plate for liquid crystal displays and organic electroluminescence (EL).

The present invention will be explained 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.

The monomers used in the examples are MA-1 to MA-3 having a photoreactive group, MB-1 to MB-2 having a non-photoreactive hydrogen-bonding functional group, MD-1 to MD-8 having a self-crosslinking site, ME-1 having a hydroxyalkyl group, and MF-1 as another component. The side chains derived from MA-1 to MA-3 correspond to side chain a, the side chains derived from MB-1 to MB-2 correspond to side chain b, the side chains derived from MD-1 to MD-8 correspond to side chain d, the side chains derived from ME-1 to ME-4 correspond to side chain e, and the side chain derived from MF-1 corresponds to side chain f.

The abbreviations of the reagents used in this example are as follows:
(Organic solvent)
CPN: Cyclopentanone cPenOH: Cyclopentanol (polymerization initiator)
V-601: 2,2'-azobis(2-methylpropionate)dimethyl (surfactant)
F563: Megafac F-563 (manufactured by DIC)
(Crosslinking catalyst)
CAT-1: 1,2-ethanedisulfonic acid dihydrate

(Polymer molecular weight measurement)
The conditions for measuring the molecular weight of the polymer are as follows.
Apparatus: Shimadzu Nexera GPC system (Shimadzu SCL-40)
Column: Shodex column (LF-804, KF-801)
Column temperature: 40°C
Eluent: Tetrahydrofuran (HPLC grade)
Flow rate: 1.0 ml/min. Standard sample for creating calibration curve: polystyrene (PStQuick E/PStQuick F) (manufactured by Tosoh Corporation)

[1] Synthesis of Monomers ME-2 to ME-4 are novel compounds, and their synthesis methods are shown below. The products described in the following Monomer Synthesis Examples were identified by ¹ H-NMR analysis (analysis conditions are as follows).

( ^1H -NMR Measurement)
Equipment: Fourier transform superconducting nuclear magnetic resonance (FT-NMR) "AVANCE III" (manufactured by BRUKER) 500MHz
Solvent: deuterated dimethylsulfoxide (DMSO-d ₆ ) or deuterated chloroform (CDCl ₃ )
Standard substance: tetramethylsilane (TMS)

<Monomer Synthesis Example 1: Synthesis of ME-2>

MB-1 (6.13 g, 20.0 mmol), tyrosol (2.77 g, 20.0 mmol), N,N-dimethyl-4-aminopyridine (DMAP, 0.2 g), and methylene chloride (30 mL) were stirred, and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC, 4.79 g, 25.0 mmol) was added at 5 ° C. (ice water bath), and the mixture was stirred at room temperature for 96 hours. Thereafter, methylene chloride was distilled off under reduced pressure, ethyl acetate was added, and the mixture was washed twice with 100 ml of pure water, dried over magnesium sulfate, and the solvent was distilled off under reduced pressure to obtain a yellow solid. This solid was purified by column chromatography (heptane / ethyl acetate, 2/1 ⇒ 1/1) and recrystallization (methanol / pure water, 2/1) to obtain the desired ME-2 (5.50 g, 12.9 mmol, yield: 64%).
¹ H-NMR (CDCl ₃ ): δ (ppm) = 1.48 (m, 4H), 1.65 (t, 1H), 1.73 (m, 2H), 1.83 (m, 2H), 1.95 (s, 3H), 2.88 (t, 2H), 3.86 (m, 2H), 4.05 (t, 2H), 4.17 (t, 2H) H), 5.55 (s, 1H), 6.10 (s, 1H), 6.95 (d, 2H), 7.13 (d, 2H), 7.27 (d, 2H), 8.12 (d, 2H).

<Monomer Synthesis Example 2: Synthesis of ME-3>

4-[[6-(acryloyloxy)hexyl]oxy]benzoic acid (14.6 g, 50.0 mmol), tyrosol (6.91 g, 50.0 mmol), N,N-dimethyl-4-aminopyridine (DMAP, 0.6 g), and methylene chloride (30 mL) were stirred, and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC, 10.5 g, 54.8 mmol) was added at 5°C (ice water bath), and the mixture was stirred for 72 hours. Thereafter, methylene chloride was distilled off under reduced pressure, ethyl acetate was added, and the mixture was washed twice with pure water (100 mL), dried over magnesium sulfate, and the solvent was distilled off under reduced pressure to obtain a yellow solid. This solid was purified by column chromatography (heptane/ethyl acetate, 2/1→1/1) and recrystallization (methanol/pure water, 2/1) to obtain the target ME-3 (10.2 g, 24.7 mmol, yield: 49%).
¹ H-NMR (DMSO-d ₆ ): δ (ppm) = 1.40 (m, 4H), 1.62 (m, 2H), 1.75 (m, 2H), 2.74 (t, 2H), 3.61 (m, 2H), 4.11 (m, 4H), 4.65 (t, 1H), 5.92 (d, 1H), 6.16 (m , 1H), 6.34 (d, 1H), 7.09 (d, 2H), 7.15 (d, 2H), 7.28 (d, 2H), 8.04 (d, 2H).

<Monomer Synthesis Example 3: Synthesis of ME-4>

<Synthesis of ME-4-1>
ME-4-1 was synthesized with reference to JP-A-2005-162688.

<Synthesis of ME-4>
MB-1 (6.13 g, 20.0 mmol), ME-4-1 (4.89 g, 20.0 mmol), N,N-dimethyl-4-aminopyridine (DMAP, 0.2 g), and methylene chloride (30 mL) were stirred, and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC, 4.79 g, 25.0 mmol) was added at 5° C. (ice water bath) and stirred for 48 hours. Thereafter, methylene chloride was distilled off under reduced pressure, ethyl acetate was added, and the mixture was washed twice with pure water (100 mL), dried over magnesium sulfate, and then the solvent was distilled off under reduced pressure to obtain a yellow solid. This solid was purified by recrystallization (ethanol) to obtain the target ME-4 (5.0 g, 9.39 mmol, yield: 47%).
¹ H-NMR (DMSO-d ₆ ): δ (ppm) = 1.41 (m, 4H), 1.44 (m, 2H), 1.64 (m, 2H), 1.88 (m, 5H), 3.58 (m, 2H), 4.09 (m, 6H), 4.57 (t, 1H), 5.66 (s, 1H), 6.02 (s , 1H), 7.02 (d, 2H), 7.10 (d, 2H), 7.30 (d, 2H), 7.61 (d, 2H), 7.69 (d, 2H), 8.08 (d, 2H).

[2] Polymer synthesis <Synthesis Example 1>
MA-1 (1.50 g, 4.50 mmol), MB-1 (5.51 g, 18.0 mmol), MB-2 (1.98 g, 4.50 mmol), MD-1 (0.600 g, 3.00 mmol) and V-601 (0.207 g, 0.90 mmol) were dissolved in CPN (24.3 g) to prepare a monomer mixed solution. Under a nitrogen atmosphere, the monomer mixed solution was dropped into CPN (10.4 g) over 2 hours at 70 ° C. After the dropwise addition was completed, the reaction was allowed to proceed at 70 ° C. for 12 hours. After the reaction was completed, the reaction solution was poured into a methanol / pure water mixed solvent, and the precipitated polymer was filtered and washed with methanol to obtain polymer powder P-1 (8.33 g). The number average molecular weight of P-1 was 39,000 and the weight average molecular weight was 143,000.

<Synthesis Examples 2 to 13>
As shown in Table 1, polymer powders P-2 to P-16 were obtained in the same manner as in Synthesis Example 1, except that the types and amounts of the monomers used were changed.

The compositions of the polymers obtained in Synthesis Examples 1 to 16 are shown in Table 1.

[3] Preparation of retardation film composition <Preparation Example 1>
CPN (8.19 g) and F563 (9.0 mg) were added to the polymer powder P-1 (1.80 g) obtained in Synthesis Example 1, and the mixture was stirred at 23° C. After dissolving the polymer, the mixture was filtered through a filter with a pore size of 5.0 μm to obtain a polymer solution T-1 (polymer concentration: 18% by mass). This polymer solution T-1 was used as it is as a material for forming a retardation film.

<Preparation Examples 2 to 16>
As shown in Table 2, polymer solutions T-2 to T-16 (polymer concentration: 18% by mass) were obtained by carrying out the same procedure as in Preparation Example 1, except that the type of polymer powder used, the amount of F563, and the presence or absence of addition of a crosslinking catalyst were changed. These polymer solutions T-2 to T-16 were used as materials for forming retardation films as they were.

In Table 2, the numbers in parentheses for the solvents indicate the ratio (mass %) of the solvent to the polymer solution.

[4] Production of single-layer retardation film <Example 1>
The polymer solution T-1 was applied onto a COP film (Zeon Corporation, ZF16-100) using a bar coater. The applied film was dried in a hot air circulating oven at 50°C for 3 minutes, and then the substrate was irradiated with 600 mJ/ ^cm2 polarized ultraviolet light having a wavelength of 365 nm from a high-pressure mercury lamp through a 300 nm long wave length pass filter and a polarizing plate. After that, it was heated for 5 minutes in an IR oven at 120°C to prepare a COP film S-1 with a retardation film. The retardation layer thickness of S-1 was measured using an F20 film thickness measurement system (Filmetrics Inc.) and found to be 3.5 μm.

<Examples 2 to 15>
COP films S-2 to S-15 with retardation films were produced in the same manner as in Example 1, except that the type of polymer solution, film thickness, exposure conditions (type of cut filter, exposure amount), and main baking conditions were changed as shown in Table 3. In Table 3, 365BPF represents a 365 nm bandpass filter, and 300LWPF represents a 300 nm long wave length pass filter.

<Comparative Example 1>
As shown in Table 3, the same procedure as in Example 1 was carried out except that the type of polymer solution, the film thickness, and the exposure conditions were changed, to produce a COP film R-1 with a retardation film.

The retardation values and crack resistance of the retardation-coated COP films S-1 to S-15 and R-1 obtained in Examples 1 to 15 and Comparative Example 1 above were evaluated using the following method.

[Evaluation of Phase Difference Value]
The linear phase difference at a wavelength of 550 nm was evaluated using an AxoScan manufactured by Axometrics, and the results are summarized in Table 3.

[Crack resistance]
The retardation film of the retardation film-attached COP film (4 x 4 cm) was attached to a glass substrate (3.5 x 3.5 cm) with an adhesive layer using a roller. The adhesive layer was an optical double-sided adhesive sheet M3D49 manufactured by Mitate Imaging Co., Ltd. Next, the excess retardation film-attached COP film was cut using a cutter, and the COP film was peeled off to obtain a glass substrate with a retardation film. The obtained glass substrate with a retardation film was visually observed to evaluate the presence or absence of cracks. When cracks were observed, it was evaluated as "x", and when no cracks were observed, it was evaluated as "○".

Comparative Example 1, which does not contain side chain d, caused cracks during transfer. On the other hand, Examples 1 to 15 contained side chain d, which is a self-crosslinking group, so cracks during transfer were suppressed and good phase difference values were shown.

Claims (10)

A single-layer retardation material obtained from a polymer composition containing: (A) a polymer having a side chain having a photoreactive site, a side chain having a non-photoreactive hydrogen-bonding functional group, and a side chain having a self-crosslinking site; and (B) an organic solvent. The single-layer retardation material according to claim 1, wherein the side chain having a photoreactive site is a side chain having a photoreactive site and a hydrogen-bonding functional group. 2. The single-layer retardation material 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 formulas (a1) to (a6), n1 and n2 are each independently 0, 1, 2, or 3. L is 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. T ¹ is 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. A ¹ , A ² , and D ¹ are each independently a single bond, -O-, -CH ₂ -, -C(═O)-O-, -O-C(═O)-, -C(═O)-NH-, or -NH-C(═O)-. However, when T ¹ is a single bond, A ² is also a single bond. Y ¹ and Y P 1 , Q 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. When the number of Q ^1s is ² , each Q ¹ may be the same or different from the others, and when the number of Q ^2s is 2, each Q ² may be the same or different from each other. 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. X ¹ and X ² are each independently a single bond, -O-, -C(=O)-O-, -O-C(=O)-, -N=N-, -CH=CH-, -C≡C-, -CH=CH-C(=O)-O-, or -O-C(=O)-CH=CH-. When the number of X ¹ is 2, each X ¹ may be the same or different from each other, and when the number of X ² is 2, each X ² may be the same or different from each other. Z ^1a and Z Each of ^2a is 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. 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 -NO ₂ , -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)-O-, -O-C(=O)-, -C(=O)-S-, or -S-C(=O)-. Each of G ¹ and G ² is independently N or CH. The dashed lines represent bonds.) 2. A single-layer retardation material comprising the side chain type polymer having a side chain having a photoreactive site according to claim 1, wherein the side chain having a photoreactive site is represented by the following formula (a1-2):

(In the formula, n1 is 0, 1 or 2. L is 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. Q ¹ is 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. When the number of Q ¹ is 2, each Q ¹ may be the same or different. X ¹ is a single bond, -O-, -C(=O)-O-, -O-C(=O)-, -N=N-, -CH=CH-, -C≡C-, -CH=CH-C(=O)-O-, or -O-C(=O)-CH=CH-. X When the number of ^{X 1} is 2, each X ¹ may be the same or different. Y ¹ is a phenylene group or a naphthylene group. Z ^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. R is a hydrogen atom. 5. The single-layer retardation material according to claim 4, wherein Y ¹ is a 1,4-phenylene group. The single-layer retardation material according to claim 1, wherein the polymer component (A) further has a side chain having a hydroxyalkyl group. 2. The single-layer retardation material according to claim 1, wherein the polymer (A) has a side chain having a moiety represented by the following formula (b):

(In the formula, R ¹ is 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 an organic group. Furthermore, -CH ₂ CH ₂ - in R ¹ may be substituted with -CH=CH-, and -CH ₂ - in R ¹ may be substituted with a group selected from the group consisting of -O-, -NH-C(=O)-, -C(=O)-NH-, -C(=O)-O-, -O-C(=O)-, -NH-, -NH-C(=O)-NH- and -C(=O)-. However, adjacent -CH ₂ -'s are not substituted with these groups at the same time.
^R4 is an aromatic group, a polycyclic aromatic group, an alicyclic group, a phenylenecyclohexylene group, a heterocyclic group, or a fused ring group.
^R5 is _-CH2- , -O-, -NH-, -C(=O)-, -C(=O)-O-, -O-C(=O)-, -CH=CH-C(=O)-O-, -C(=O)-NH-, -NH-C(=O)- or -NH-C(=O)-NH-.
R ⁶ 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. In addition, -CH ₂ - in R ⁶ may be substituted with a group selected from the group consisting of -O-, -NH-, and -C(═O)-. Adjacent -CH ₂ - may also be substituted with these groups at the same time.
A 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, 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 group, 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 lines represent bonds.) The single-layer retardation material according to claim 7, wherein the number of ring structures in the side chain represented by the above formula (b) is three or less. The single-layer retardation material according to claim 1, in which the side-chain polymer exhibits liquid crystallinity. A retardation film obtained from the single-layer retardation material according to claim 1, in which the side-chain polymer exhibits liquid crystallinity.