Photo-alignment copolymer, optical anistropic film and its preparation method

Patent metadata

Field	Value
Publication number	US-9720136-B2
Application number	US-201314419450-A
Country	US
Kind code	B2
Filing date	Aug 27, 2013
Priority date	Aug 27, 2012
Publication date	Aug 1, 2017
Grant date	Aug 1, 2017

Abstract

This invention relates to a photo-alignment copolymer which enables the formation of an optical anisotropic film that exhibits superior optical anisotropy, an optical anisotropic film using the photo-alignment copolymer and a method of manufacturing the optical anisotropic film. The photo-alignment copolymer includes both of a photo-alignment repeating unit having a photo-reactive functional group such as a cinnamate-based functional group, a chalcone-based functional group, an azo-based functional group or a coumarin-based functional group, and a repeating unit having a specific structure able to increase optical anisotropy.

First claim

What is claimed is:

1. A photo-alignment copolymer, comprising:
a photo-alignment repeating unit of Chemical Formula 1; and
a repeating unit of Chemical Formula 2 below:

wherein A is each independently hydrogen or C 1 -C 3 alkyl,
L′ is a spacer group having a combination of at least one bivalent connecting group selected from the group consisting of a single bond, carbonyl, —C(═O)O—, —OC(═O)—, —O—, —S—, substituted or unsubstituted C 1 -C 20 alkylene and substituted or unsubstituted C 6 -C 40 arylene, and
W is a photo-reactive functional group of Chemical Formula 1a,

wherein E is a single bond; —O—; substituted or unsubstituted C 1 -C 20 alkylene; or substituted or unsubstituted C 6 -C 40 aryleneoxide,
Y and Z are each independently hydrogen; or substituted or unsubstituted C 1 -C 20 alkyl,
R 10 , R 11 , R 12 and R 13 are identical to or different from each other and are each independently selected from the group consisting of hydrogen; halogen; substituted or unsubstituted C 1 -C 20 alkyl; substituted or unsubstituted C 4 -C 8 cycloalkyl; substituted or unsubstituted C 1 -C 20 alkoxy; substituted or unsubstituted C 6 -C 30 aryloxy; substituted or unsubstituted C 6 -C 40 aryl; C 6 -C 40 heteroaryl containing a hetero element of Group 14, 15 or 16; substituted or unsubstituted C 6 -C 40 alkoxyaryl; cyano; nitrile; nitro; and hydroxyl,
R 14 is halogen; unsubstituted C 1 -C 20 alkoxy; or cyano,

wherein A is each independently hydrogen or C 1 -C 3 alkyl,
B and B′ are each independently carbonyl, —C(═O)O—, —OC(═O)—, —O— or —S—,
L is a single bond, or substituted or unsubstituted C 1 -C 20 alkylene,
S 1 is —C(═O)O—, and
R 1 is a substituted or unsubstituted C 1 -C 20 alkyl.

2. The photo-alignment copolymer of claim 1 , wherein the spacer group of L′ has a structure in which a single bond or carbonyl, substituted or unsubstituted C 1 -C 20 alkylene, and substituted or unsubstituted C 6 -C 40 arylene are sequentially connected via —O—.

3. The photo-alignment copolymer of claim 1 , wherein in Chemical Formula 2, B is —C(═O)O—, L is substituted or unsubstituted C 1 -C 20 alkylene, and B′ is —O—.

4. The photo-alignment copolymer of claim 2 , wherein C 6 -C 40 arylene contained in the spacer group of L′ is substituted with at least one functional group selected from the group consisting of C 1 -C 6 alkyl, C 1 -C 6 halogenated alkyl, halogen, C 1 -C 6 alkoxy, C 1 -C 6 halogenated alkoxy, C 1 -C 6 alkylester, C 1 -C 6 halogenated alkylester, C 1 -C 6 alkylate and C 1 -C 6 halogenated alkylate.

5. The photo-alignment copolymer of claim 1 , wherein the photo-alignment repeating unit and the repeating unit of Chemical Formula 2 are contained at a molar ratio of the photo-alignment repeating unit:the repeating unit of Chemical Formula 2=10:90 to 99:1.

6. The photo-alignment copolymer of claim 1 , which has a weight average molecular weight of 20,000 to 1,000,000.

7. A composition for forming an optical anisotropic film, comprising the photo-alignment copolymer of claim 1 .

8. The composition of claim 7 , further comprising a reactive mesogen.

9. The composition of claim 8 , wherein the reactive mesogen includes a compound of Chemical Formula 3 or 4 below:

in Chemical Formulas 3 and 4,
L 1 and L 2 are each independently selected from the group consisting of hydrogen, halogen, substituted or unsubstituted C 1 -C 20 alkyl, substituted or unsubstituted C 1 -C 3 alkyl ester, substituted or unsubstituted C 1 -C 8 alkyl ether, and substituted or unsubstituted C 1 -C 3 alkyl ketone,
B 1 and B 2 are each independently substituted or unsubstituted C 6 -C 20 arylene or substituted or unsubstituted C 4 -C 3 cycloalkylene,
R1 and R2 are each independently (meth)acryl or epoxy,
X 1 is selected from the group consisting of C 1 -C 7 alkyl unsubstituted or substituted with fluorine, C 1 -C 7 alkoxy unsubstituted or substituted with fluorine, C 2 -C 7 alkenyl unsubstituted or substituted with fluorine, C 2 -C 7 alkenyloxy unsubstituted or substituted with fluorine, and C 1 -C 7 alkoxyalkyl unsubstituted or substituted with fluorine, and
Z 1 , Z 2 , Z 3 and Z 4 are each independently a single bond, O—, —S—, —COO—, —OCO— or —OC(O)O—.

10. The composition of claim 7 , further comprising a photocurable binder.

11. The composition of claim 10 , wherein the photocurable binder includes at least one polyfunctional (meth)acrylate compound selected from the group consisting of pentaerythritol triacrylate, tris(2-acrylolyloxyethyl)isocynurate, trimethylolpropane triacrylate and dipentaerythritol hexaacrylate.

12. The composition of claim 7 , further comprising a photoinitiator for initiating UV curing.

13. The composition of claim 7 , comprising, based on a total weight of solids of the composition, 1 to 50 wt % of the photo-alignment copolymer, 10 to 90 wt % of a reactive mesogen, 1 to 50 wt % of a photocurable binder, and 0.1 to 5 wt % of a photoinitiator.

14. The composition of claim 7 , further comprising an organic solvent.

15. A method of manufacturing an optical anisotropic film, comprising:
irradiating the composition of claim 7 with polarized UV, thus optically aligning at least a portion of a photo-reactive functional group linked to a photo-alignment copolymer; and
thermally treating the composition in which at least a portion of the photo-reactive functional group is optically aligned, thus increasing optical anisotropy.

16. The method of claim 15 , further comprising photocuring a reactive mesogen or a photocurable binder contained in the composition having increased optical anisotropy, after thermally treating.

17. The method of claim 16 , wherein the reactive mesogen is subjected to liquid crystal alignment by the optically aligned photo-reactive functional group of the photo-alignment copolymer.

18. An optical anisotropic film, formed on a substrate and comprising a cured product of the composition of claim 7 .

19. The optical anisotropic film of claim 18 , which includes a single layer of the cured product.

20. The optical anisotropic film of claim 18 , wherein the cured product includes a photo-alignment copolymer in which at least a portion of a photo-reactive functional group is optically aligned, a cured product of a reactive mesogen subjected to liquid crystal alignment by the optically aligned photo-reactive functional group, and a binder resin including a (meth)acrylate-based crosslinked polymer.

21. The optical anisotropic film of claim 18 , which functions as a liquid crystal alignment film, an optical filter, a phase difference film, a polarizer or a polarized light emitter.

Assignees

• Lg Chemical Ltd

Inventors

• Choi Dai Seung
• Yoo Dong Woo
• Chun Sung-Ho
• Jang Hyeong Bin
• Hong Mi Ra

Classifications

• G02B1/04 Primary

  made of organic materials, e.g. plastics (G02B1/08 takes precedence) · CPC title

• C08L2666/70

  Organic dyes or pigments; Optical brightening agents · CPC title

• C08F220/30

  containing aromatic rings in the alcohol moiety · CPC title

• C08F222/20

  Esters containing oxygen in addition to the carboxy oxygen · CPC title

• C08F220/303

  and one or more carboxylic moieties in the chain · CPC title