Thermotropic liquid crystal polyesters and a method for their production
US4892926A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 31, 1988 |
| Grant date | Jan 9, 1990 |
| Priority date | — |
| Expiry date | Mar 31, 2008 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08G63/60
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
A thermotropic liquid crystal polyester consisting essentially of ethylene glycol residue, terephthalic acid residue and parahydroxybenzoic acid residue wherein the mol ratio of ethylene glycol residue to terephthalic acid residue is substantially about 1:1 and the mol ratio of terephthalic acid residue to parahydroxybenzoic acid residue is in the range of about 5:95 to about 25:75, the polyester having an intrinsic viscosity of at least about 0.5 dl/g measured in a 50:50 by weight solvent mixture of phenol and 1,1,2,2-tetrachlorethane at 20.degree. C., and a transmittance of at least about 80% to 530 nm light at a light path length of 10 mm measured using a 0.4 wt. % solution of the polyester in said solvent mixture. A method for forming the thermotropic liquid crystal polyester is also disclosed. The liquid crystal polyester of the present invention is useful for injection molding applications and various extrusion molding purposes, such as the manufacture of films, sheets, fibers, pipes, etc.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.