# US 5,705,279 A · Fibrillar copolyester having a large aspect ratio, production method for the same, and a resinous composite material containing the same as reinforcement > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,705,279 A - Document ID: US5705279A - Status: Granted - Kind: A - Application number: 08/591,729 - Filed: 1996-01-25 - Granted: 1998-01-06 - Earliest claimed: 1996-01-25 - Assignees: Polyplastics Co., Ltd. - Inventors: Ayako Migita; Kenji Hijikata - Web page: https://patentgrep.com/patent/US5705279A ## CPC - C08G 63/065: {the hydroxy and carboxylic ester groups being bound to aromatic rings} - C08L 67/02: Polyesters derived from dicarboxylic acids and dihydroxy compounds (C08L67/06 takes precedence) - Y10T 428/31786: Of polyester [e.g., alkyd, etc.] - C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS - C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06) - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract A fibrillar copolyester having excellent heat resistance, a reinforcing effect and a large aspect ratio is produced with high dimensional stability and efficiency. A specific fibrillar copolyester having an aspect ratio of at least 3.0 is produced by polymerizing with shearing specific hydroxy aromatic carboxylic acid monomers as starting materials in a nonpolar solvent having 10 or more carbon atoms. Such hydroxy aromatic carboxylic acid monomers preferably have acetylated hydroxyl groups when copolymerized. Additionally, substituents other than hydrogen atoms optionally may be present on the rings of the aromatic monomers when forming the fibrillar copolyester. ## Claims ### Claim 1 A process for producing a fibrillar copolyester having an aspect ratio of at least 3.0, comprising copolymerizing with shearing at least two different hydroxy aromatic carboxylic acid monomers selected from the group consisting of parahydroxybenzoic acid, 2-hydroxy-6-naphthoic acid, and 4'-hydroxy-4-biphenylcarboxylic acid wherein one or more of said monomers optionally possess hydroxyl groups that are acetylated while present in a nonpolar solvent having 10 or more carbon atoms. ### Claim 2 (depends on 1) The process as claimed in claim 1, in which the copolyester is composed of 85 to less than 100 mole percent of one of said monomers and more than 0 to 15 of another of said monomers. ### Claim 3 (depends on 1) The process as claimed in claim 1, in which the copolyester has the formula (1): ##STR3## wherein m and n are molar fractions of the recurring units of the polymer of the formula (1), provided that m is 85 or more and less than 100 and n is more than 0 and 15 or less, Ar.sub.1 is a group selected from 1,4-phenylene, 2,6-naphthyl and 4,4'-biphenyl, and Ar.sub.2 is at least one group selected from 1,4-phenylene, 2,6-naphthyl, and 4,4'-biphenyl, with the proviso that Ar.sub.1 and Ar.sub.2 are different. ### Claim 4 (depends on 1) The process as claimed in claim 1, in which a shearing zone is formed during the polymerization with a stirrer having a rotation speed of at least 80 rpm or more. ### Claim 5 (depends on 1) The process as claimed in claim 1, in which an acetoxy group is introduced into said hydroxy aromatic carboxylic acid monomers in a polymerization reactor and the resulting acetylated acid monomers are polymerized. ### Claim 6 (depends on 1) The process as claimed in claim 1, in which the polymerization is carried out under a reduced pressure. ### Claim 7 (depends on 1) A process as claimed in claim 1, wherein said nonpolar solvent is selected from the group consisting of liquid paraffin, and diphenyl ketone. ### Claim 8 (depends on 1) The fibrillar copolyester produced by the process as defined in claim 1. ### Claim 9 (depends on 8) A resin composite material containing the fibrillar copolyester as defined in claim 8 as reinforcement in an amount of at least 5% by weight and a second resinous material. ### Claim 10 (depends on 9) A resin composite material according to claim 9, wherein said second resinous material is polybutylene terephthalate. ### Claim 11 A process for producing a fibrillar copolyester having an aspect ratio of at least 3.0, comprising copolymerizing with shearing at a stirrer rotation speed of at least 80 rpm at least two different hydroxy aromatic carboxylic acid monomers selected from the group consisting of parahydroxybenzoic acid, 2-hydroxy-6-naphthoic acid, and 4'-hydroxy-4-biphenylcarboxylic acid, while present in a nonpolar solvent selected from the group consisting of liquid paraffin and diphenyl ketone. ### Claim 12 (depends on 11) A process as claimed in claim 11 wherein said monomers are parahydroxybenzoic acid and 2-hydroxy-6-naphthoic acid. ### Claim 13 (depends on 11) A process as claimed in claim 11 wherein said shearing is created by a stirrer rotation speed of 200 rpm. ### Claim 14 (depends on 11) A process as claimed in claim 11 wherein said nonpolar solvent is liquid paraffin. ### Claim 15 (depends on 11) A process as claimed in claim 11 wherein said nonpolar solvent is diphenyl ketone. ### Claim 16 (depends on 11) A fibrillar copolyester produced by the process as defined in claim 11. ### Claim 17 (depends on 16) A resin composite material containing the fibrillar copolymer as defined in claim 16 as reinforcement in an amount of at least 5% by weight and a second resinous material.