# US 7,408,020 B2 · Composition for LC alignment film using diamine having dendron side chain

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- Number: US 7,408,020 B2
- Document ID: US7408020B2
- Status: Granted
- Kind: B2
- Application number: 11/219,046
- Filed: 2005-09-01
- Published: 2006-07-06
- Granted: 2008-08-05
- Earliest claimed: 2004-12-31
- Assignees: Cheil Industries Inc.
- Inventors: Jae Min Oh; O Bum Kwon; Won Seok Dong; Bum Jin Lee; Jong Seob Kim
- Web page: https://patentgrep.com/patent/US7408020B2

## CPC

- C08G 73/1085: {Polyimides with diamino moieties or tetracarboxylic segments containing heterocyclic moieties}
- C09K 2323/00: Functional layers of liquid crystal optical display excluding electroactive liquid crystal layer characterised by chemical composition
- C09K 2323/02: Alignment layer characterised by chemical composition
- C09K 2323/025: Polyamide
- G02F 1/133723: {Polyimide, polyamide-imide}
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS

## Abstract

Disclosed herein is an LC aligning agent using diamine having dendron side chains. In detail, the present invention relates to a composition for an LC alignment film which employs diamine having dendron side chains to produce polyamic acid, followed by imidization. When the LC alignment film is applied to a liquid crystal display device, high heat resistance, high penetration in a visible ray range, excellent alignment, and a high voltage holding ratio are assured. Even though it contains a small amount of functional diamine, a high pretilt angle can be assured. Thus, the pretilt angle is easily controlled and a vertical aligning force is improved.

## Claims

### Claim 1

A diamine compound having a dendron side chain, which is expressed by the following Formula 1
wherein, A and A′ are each a single bond, —CH2O—, OCH2—, —OCO—, or —NHCO—, B is —O— or a single bond, m is an integer from 1 to 3, n is an integer of 2 or 3, G is a single bond (when m is 1), a benzene ring having an equivalence of 3
when m is 2), or a benzene ring having an equivalence of 4
when m is 3), and R is each independently a linear, branched, or cyclic alkyl or fluoroalkyl group having from 1 to 30 carbons.

### Claim 2 (depends on 1)

A composition for a liquid crystal alignment film, comprising:
polyamic acid which is produced by copolymerizing the diamine compound according to claim 1, aliphatic cyclic acid dianhydride, aromatic cyclic acid dianhydride, and optionally an aromatic cyclic diamine compound.

### Claim 3 (depends on 2)

The composition as set forth in claim 2, wherein content of the polyamic acid is 1-40 wt % and content of a solvent is 60-99 wt %.

### Claim 4 (depends on 2)

The composition as set forth in claim 2, wherein the polyamic acid is expressed by the following Formula 4
wherein, X and Y are each independently acid dianhydride and one or more functional groups selected from functional groups expressed by the following Formula 5 or 6, Z includes one or more functional groups selected from functional groups expressed by the following Formula 7, Z′ includes one or more functional groups selected from functional groups expressed by the following Formulae 1a and 7, and at least one Z′ of polyamic acid monomer expressed by Formula 4 is selected from functional groups expressed by the following Formula 1a
wherein, A and A′ are each a single bond, —CH2O—, OCH2—, —OCO—, or —NHCO—, B is —O— or a single bond, m is an integer of 1 to 3, n is an integer of 2 or 3, G is a single bond (when m is 1), a benzene ring having an equivalence of 3
when m is 2), or a benzene ring having an equivalence of 4
when m is 3), and R is each independently a linear, branched, or cyclic alkyl or fluoroalkyl group having 1 to 30 carbons
wherein, X1, X2, X3, and X4 are each independently —H, —CH3, —F, —Br, —Cl, —CN, —OH, or —NO2.

### Claim 5 (depends on 2)

The composition as set forth in claim 2, wherein an average molecular weight of the polyamic acid is 5000-500,000 g/mol.

### Claim 6 (depends on 2)

The composition as set forth in claim 2, wherein the aromatic cyclic diamine includes one or more selected from a group consisting of p-phenylene diamine (p-PDA), 4,4-methylene dianiline (MDA), 4,4-oxydianiline (ODA), m-bis(aminophenoxy)diphenylsulfone (m-BAPS), p-bis(aminophenoxy)diphenylsulfone (p-BAPS), 2,2-bis(aminophenoxy)phenylpropane (BAPP), and 2,2-bis(aminophenoxy)phenylhexafluoropropane (HF-BAPP), the aromatic cyclic acid dianhydride includes one or more selected from a group consisting of pyromellitic dianhydride (PMDA), biphthalic dianhydride (BPDA), oxydiphthalic dianhydride (ODPA), benzophenonetetracarboxylic dianhydride (BTDA), and hexafluoroisopropylidene diphthalic dianhydride (6-FDA), and the aliphatic cyclic acid dianhydride includes one or more selected from a group consisting of 5-(2,5-dioxotetrahydrofuryl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride (DOCDA), bicycloocten-2,3,5,6-tetracarboxylic dianhydride (BODA), 1,2,3,4-cyclobutanetetracarboxylic dianhydride (CBDA), 1,2,3,4-cyclopentanetetracarboxylic dianhydride (CPDA), and 1,2,4,5-cyclohexanetetracarboxylic dianhydride (CHDA).

### Claim 7 (depends on 2)

The composition as set forth in claim 2, wherein the polyamic acid contains 0.1-100 mol % diamine expressed by Formula 1 and 0-99.9 mol % aromatic cyclic diamine based on total diamine, and 10-80 mol % aromatic cyclic acid dianhydride and 20-90 mol % aliphatic cyclic acid dianhydride based on total acid dianhydride components.

### Claim 8 (depends on 2)

The composition as set forth in claim 2, wherein a solvent includes one or more selected from a group consisting of N-methyl-2-pyrrolidone (NMP), gamma-butyrolactone (GBL), dimethylformamide (DMF), dimethylacetamide (DMAc), and tetrahydrofuran (THF).

### Claim 9 (depends on 2)

A liquid crystal alignment film for twisted nematic (TN) or vertical alignment (VA) application, which is produced by applying the composition for the liquid crystal alignment film according to claim 2 and totally or partially imidizing the applied composition.

### Claim 10 (depends on 9)

A liquid crystal display device comprising the liquid crystal alignment film according to claim 9.