# US 6,720,040 B2 · Material for liquid-crystal alignment film, liquid-crystal display element, process for its production and liquid-crystal display unit > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 6,720,040 B2 - Document ID: US6720040B2 - Status: Granted - Kind: B2 - Application number: 09/949,639 - Filed: 2001-09-12 - Published: 2003-01-30 - Granted: 2004-04-13 - Earliest claimed: 2001-07-13 - Assignees: Hitachi, Ltd. - Inventors: Nobuhito Katsumura; Haruhiko Kikawa; Takashi Inoue; Masahiro Yamada; Yasuo Koike; Nobuhiko Fukuoka; Hiromu Terao - Web page: https://patentgrep.com/patent/US6720040B2 ## CPC - G02F 1/133723: {Polyimide, polyamide-imide} - C09K 2323/00: Functional layers of liquid crystal optical display excluding electroactive liquid crystal layer characterised by chemical composition - C09K 2323/025: Polyamide - C09K 2323/027: Polyimide - 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 - C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE ## Abstract A material for a liquid-crystal alignment film which comprises as a first polyamide a C3 to C10 alkyl ester of a polyamic acid whose acid anhydride residual group is any of: and as a second polyamide a C3 to C10 alkyl ester of a polyamic acid whose acid anhydride residual group is: is provided. The use of this material materializes a liquid-crystal alignment film having a high pre-tilt angle of molecules to the substrate, and having superiority in respect of electrical properties such as voltage holding ratio and residual DC voltage, adherence to substrates, printability, and step-covering properties. ## Claims ### Claim 1 A material for a liquid-crystal alignment film which comprises: (i) a first polyamide having a first repeating unit represented by the following Formula (1) and having a weight-average molecular weight of from 5,000 to 200,000; wherein R1 is a tetravalent organic group represented by any of the following structural formulas (2), R2 is a divalent organic group, and R3 is an alkyl group having 3 to 10 carbon atoms or a fluoroalkyl group having 3 to 10 carbon atoms; and (ii) a second polyamide having a second repeating unit represented by the following Formula (3) and a third repeating unit represented by the following Formula (5), and having a weight-average molecular weight of from 5,000 to 200,000; wherein R4 is represented by any of the following structural formula (11), R5 is a divalent organic group, and R6 is an alkyl group having 3 to 10 carbon atoms or a fluoroalkyl group having 3 to 10 carbon atoms, wherein Z1 to Z8 are each any of a hydrogen atom, an alkyl group having 1 to 8 carbon atoms and an aryl group having 6 to 18 carbon atoms; and n is an integer of 1 to 8, m is an integer of 1 to 4, p is an integer of 1 to 8, q is an integer of 1 to 4, r is an integer of 1 or 2, s is an integer of 1 to 4, t is an integer of 1 or 2, u is an integer of 1 to 4, v is an integer of 1 or 2, and w is an integer of 1 to 4, wherein R7 is a straight-chain alkyl group having 6 to 20 carbon atoms or a straight-chain fluoroalkyl group having 6 to 20 carbon atoms. ### Claim 2 (depends on 1) The material for a liquid-crystal alignment film according to claim 1, wherein; said first polyamide and said second polyamide are in a weight ratio of from 99:1 to 5:95; and the number of the third repeating unit with respect to the number of total repeating units in one molecule of said second polyamide is in a proportion of from 1 mole % to 50 mole %. ### Claim 3 (depends on 1) The material for a liquid-crystal alignment film according to claim 1, wherein said first polyamide further has a fourth repeating unit represented by the following Formula (6): wherein R8 is a tetravalent organic group represented by any of the following structural formulas (7): and the number of the first repeating unit with respect to the number of total repeating units in one molecule of said first polyamide is in a proportion of at least 30 mole % in terms of material ratio of acid anhydrides. ### Claim 4 (depends on 1) The material for a liquid-crystal alignment film according to claim 1, wherein at least part of a plurality of R2s contained in one molecule of said first polyamide has at least one of a carboxyl group and a hydroxyl group as a substituent. ### Claim 5 (depends on 1) The material for a liquid-crystal alignment film according to claim 1, wherein at least part of a plurality of R2s contained in one molecule of said first polyamide is an organic group represented by the following Formula (8): wherein Y1 to Y4 are each a hydrogen atom, a hydroxyl group, a carboxyl group having 1 to 8 carbon atoms, an aldehyde group having 1 to 8 carbon atoms, an alkyl group having 1 to 8 carbon atoms or an aryl group having 6 to 18 carbon atoms; and R9 is a divalent organic group or an oxygen atom. ### Claim 6 (depends on 4) The material for a liquid-crystal alignment film according to claim 4, wherein at least part of a plurality of R2s contained in one molecule of said first polyamide is an organic group represented by the following Formula (8): wherein Y1 to Y4 are each a hydrogen atom, a hydroxyl group, a carboxyl group having 1 to 8 carbon atoms, an aldehyde group having 1 to 8 carbon atoms, an alkyl group having 1 to 8 carbon atoms or an aryl group having 6 to 18 carbon atoms; and R9 is a divalent organic group or an oxygen atom. ### Claim 7 (depends on 5) The material for a liquid-crystal alignment film according to claim 5, wherein said R2 is an organic group represented by the following Formula (9): ### Claim 8 (depends on 6) The material for a liquid-crystal alignment film according to claim 6, wherein said R2 is an organic group represented by the following Formula (9): ### Claim 9 (depends on 1) The material for a liquid-crystal alignment film according to claim 1, wherein 80 mole % or less of a plurality of R2s contained in one molecule of said first polyamide is a silicon-containing organic group. ### Claim 10 (depends on 1) The material for a liquid-crystal alignment film according to claim 1, wherein 80 mole % or less of a plurality of R5s contained in one molecule of said second polyamide is a silicon-containing organic group. ### Claim 11 (depends on 9) The material for a liquid-crystal alignment film according to claim 9, wherein said silicon-containing organic group is at least one of organic groups represented by any of the following structural formulas (10): ### Claim 12 (depends on 10) The material for a liquid-crystal alignment film according to claim 10, wherein said silicon-containing organic group is at least one of organic groups represented by any of the following structural formulas (10): ### Claim 13 (depends on 1) The material for a liquid-crystal alignment film according to claim 1, which further comprises a solvent, and has a solid-matter concentration of from 1% by weight to 70% by weight. ### Claim 14 (depends on 1) A liquid-crystal display element comprising: two substrates each having an electrode, wherein said electrode of one substrate and said electrode of another substrate are disposed opposingly to each other; a liquid crystal held between the substrates; and a liquid-crystal alignment film disposed between the liquid crystal and the electrode; wherein said liquid-crystal alignment film each comprising a cured product of the material for a liquid-crystal alignment film according to claim 1. ### Claim 15 (depends on 14) A liquid-crystal display unit comprising the liquid-crystal display element according to claim 14.