Two-stage process for preparing aromatic polyamide film
US4971744A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 21, 1989 |
| Grant date | Nov 20, 1990 |
| Priority date | — |
| Expiry date | Aug 21, 2009 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08J2377/10
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
A process for preparing aromatic polyamide film wherein an aromatic diamine and an aromatic diacidchloride are dissolved in an amide polymerization solvent containing an inorganic salt, a partial polymerization is effected at a low temperature to form an optically anisotropic liquid crystalline prepolymer dope, continuously extruding through a film die under a draw ratio or subjecting to a shear and contacting the prepolymer with a second solvent which is a polymerization accelerating-precipitation solvent to obtain an aromatic polyamide film free of crystal defect layer perpendicular to the film axis and having high strength and a high degree of molecular orientation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.