# US 5,707,566 A · Process for preparing high performance polarizer films > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,707,566 A - Document ID: US5707566A - Status: Granted - Kind: A - Application number: 08/459,907 - Filed: 1995-06-02 - Granted: 1998-01-13 - Earliest claimed: 1995-06-02 - Assignees: Hoechst Celanese Corporation - Inventors: Sunny S. Shen; Tze-Pei Tien; Hyun Nam Yoon - Web page: https://patentgrep.com/patent/US5707566A ## CPC - C08J 5/18: Manufacture of films or sheets - C09K 19/60: Pleochroic dyes - G02B 5/3016: {involving passive liquid crystal elements (optical properties of liquid crystals G02F1/0063; polarising elements associated with active liquid crystal devices G02F1/133528)} - C08J 2367/04: Polyesters derived from hydroxy carboxylic acids, e.g. lactones (C08J2367/06 takes precedence) - C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29) - C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS ## Abstract This invention provides a novel process to prepare high performance polarizing film. In one embodiment, the process includes melt-blending a film-forming wholly aromatic thermotropic liquid crystalline polyester and a dichroic dye and then extruding the blend at a suitable temperature to yield polarizer films with superior polarizing efficiency and thermal and humidity stability. ## Claims ### Claim 1 A process to prepare a polarizing film, which film possesses a polarizing efficiency of at least 70%, said process comprising: (a) bringing together at least one film-forming, wholly aromatic thermotropic liquid crystalline polyester and one or more dichroic dye into a mix; (b) blending said mix at a temperature between 170.degree. C. and the melt temperature of said polymer to make an uniform blend; and (c) extruding said blend in a suitable extruder at a temperature between 170.degree. C. and the melt temperature of said polymer to yield the polarizing film, wherein said polyester comprises repeat units corresponding to the formula: --›P.sup.1 !.sub.m --›P.sup.2 !.sub.n --›P.sup.3 !.sub.q --›P.sup.4 !.sub.r --›P.sup.5 !.sub.s -- wherein P.sup.1, P.sup.2, P.sup.3, P.sup.4 and P.sup.5 represent monomeric moieties, with P.sup.1 being an aromatic hydroxy carboxylic acid, P.sup.2 being an aromatic dicarboxylic acid, P.sup.3 being a phenol, P.sup.4 being a second aromatic hydroxy carboxylic acid moiety different from P.sup.1, and P.sup.5 being a second phenolic moiety different from P.sup.3, and m, n, q, r and s represent mole percent of the respective monomers individually with P.sup.1 and P.sup.2 in the range 5-40 mole percent, P.sup.3 in the range 5-30 mole percent, and P.sup.4 and P.sup.5 in the range 5-20 mole percent. ### Claim 2 (depends on 1) The process of claim 1, wherein P.sup.1 is selected from the group consisting of 4-hydroxy benzoic acid, 2-hydroxy-6-naphthoic acid, and 4-carboxy-4'-hydroxy-1,1'-biphenyl. ### Claim 3 (depends on 1) The process of claim 1, wherein P.sup.2 is selected from the group consisting of terephthalic acid, isophthalic acid, phthalic acid, 2-phenylterephthalic acid, 1,2-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 2,6-naphthalene dicarboxylic acid and 4,4'-biphenyldicarboxylic acid. ### Claim 4 (depends on 1) The process of claim 1, wherein P.sup.3 is selected from the group consisting of resorcinol, hydroquinone, methyl hydroquinone, phenyl hydroquinone, catechol, 4,4'-dihydroxybiphenyl and acetaminophen. ### Claim 5 (depends on 1) The process of claim 1, wherein said P.sup.5 is a diphenol selected from resorcinol, hydroquinone, catechol, 4,4'-dihydroxybiphenyl, bisphenol-A and acetaminophen. ### Claim 6 (depends on 2) The process of claim 2, wherein P.sup.1 is 4-hydroxy benzoic acid. ### Claim 7 (depends on 2) The process of claim 2, wherein P.sup.1 is 2-hydroxy-6-naphthoic acid. ### Claim 8 (depends on 3) The process of claim 3, wherein P.sup.2 is terephthalic acid. ### Claim 9 (depends on 4) The process of claim 4, wherein P.sup.3 is resorcinol. ### Claim 10 (depends on 4) The process of claim 4, wherein P.sup.3 is 4,4'-dihydroxybiphenyl. ### Claim 11 (depends on 1) The process of claim 1, wherein said P.sup.4 is 4-hydroxy benzoic acid. ### Claim 12 (depends on 5) The process of claim 5, wherein said P.sup.5 is resorcinol. ### Claim 13 (depends on 1) The process of claim 1, wherein said dye is selected from the group consisting of straight chain dye, branched dye, direct dye, disperse dye, solvent dye and acidic dye. ### Claim 14 (depends on 1) The process of claim 1, wherein said dye is selected from the group consisting of azo dyes, anthraquinone dyes, Disperse Red, Blue 214, Red 60, Yellow 56, Black 17, 19 and 154, Brown 44, 106, 195, 210, 242 and 247, Blue 1, 15, 22, 78, 90, 98, 151, 168, 202, 236, 249, and 270, Violet 9, 12, 51, and 98, Green 1 and 85, Yellow 8, 12, 44, 86, and 87, Orange 26, 39, 106 and 107, and Methylene violet Bernthsen. ### Claim 15 (depends on 14) The process of claim 14, wherein said dye is an anthraquinone dye. ### Claim 16 (depends on 1) The process of claim 1, wherein said blend is prepared at about the melt temperature of said polymer and said extrusion is performed at about the melt temperature of said polymer. ### Claim 17 A process to prepare a polarizing film, which film possesses a polarizing efficiency of at least 70%, said process comprising: (a) bringing together at least one film-forming, wholly aromatic thermotropic liquid crystalline polyesteramide and one or more dichroic dye into a mix; (b) blending said mix at a temperature between 170.degree. C. and the melt temperature of said polymer to make an uniform blend; and (c) extruding said blend in a suitable extruder at a temperature between 170.degree. C. and the melt temperature of said polymer to yield the polarizing film, wherein said polyesteramide comprises repeat units corresponding to the formula: --›P.sup.1 !.sub.m --›P.sup.2 !.sub.n --›P.sup.3 !.sub.q --›P.sup.4 !.sub.r --›P.sup.5 !.sub.s -- wherein P.sup.1, P.sup.2, P.sup.3, P.sup.4 and P.sup.5 represent monomeric moieties, with P.sup.1 being an aromatic amino carboxylic acid, P.sup.2 being an aromatic dicarboxylic acid, P.sup.3 being a phenol, P.sup.4 being an aromatic hydroxy carboxylic acid, and P.sup.5 being a second phenolic moiety different from P.sup.3, and m, n, q, r and s represent mole percent of the respective monomers individually with P.sup.1 and P.sup.2 in the range 5-40 mole percent, P.sup.3 in the range 5-30 mole percent, and P.sup.4 and P.sup.5 in the range 5-20 mole percent. ### Claim 18 (depends on 17) The process of claim 17, wherein P.sup.1 is 4-aminobenzoic acid. ### Claim 19 A process of preparing a polarizing film which film possesses a polarizing efficiency of at least 70%, said process comprising: (a) bringing together at least one film-forming, wholly aromatic thermotropic liquid crystalline polyester and one or more dichroic dye into a mix; (b) blending said mix at a temperature between 170.degree. C. and the melt temperature of said polymer to make an uniform blend; and (c) molding said blend in a suitable molder at temperatures between 170.degree. C. and the melt temperature of said polymer to yield the polarizing film, wherein said polyester comprises repeat units corresponding to the formula: --›P.sup.1 !.sub.m --›P.sup.2 !.sub.n --›P.sup.3 !.sub.q --›P.sup.4 !.sub.r --›P.sup.5 !.sub.s -- wherein P.sup.1, P.sup.2, P.sup.3, P.sup.4 and P.sup.5 represent monomeric moieties, with P.sup.1 being an aromatic hydroxy carboxylic acid, P.sup.2 being an aromatic dicarboxylic acid, P.sup.3 being a phenol, P.sup.4 being a second aromatic hydroxy carboxylic acid moiety different from P.sup.1, and P.sup.5 being a second phenolic moiety different from P.sup.3, and m, n, q, r and s represent mole percent of the respective monomers individually with P.sup.1 and P.sup.2 in the range 5-40 mole percent, P.sup.3 in the range 5-30 mole percent, and P.sup.4 and P.sup.5 in the range 5-20 mole percent. ### Claim 20 (depends on 19) The process of claim 19, wherein said blending and said molding are performed at the melt temperature of said polymer.