Non-fibrous polymer solution of para-aramid with high relative viscosity
US7754797B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 4, 2004 |
| Grant date | Jul 13, 2010 |
| Priority date | — |
| Expiry date | Oct 2, 2025 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08J2377/10
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
The invention relates to a non-fibrous polymer solution essentially consisting of 1 to 8 wt. % para-aramid, at least 50 mole % of the aromatic moieties thereof being unsubstituted, in a mixture of a) a polar amide solvent selected from N-methyl-2-pyrrolidone, N,N′-dimethyl-formamide, N,N′-dimethylacetamide, tetramethylurea, and mixtures thereof; b) between 0.7 mole of an alkali or alkaline earth metal chloride per mole amide groups of the para-aramid and 7.5 wt. % of the alkali or alkaline earth metal chloride, and c) water; and wherein at least 50 wt. % of the formed hydrochloric acid has been neutralized to obtain a solution having a dynamic viscosity which is at least a factor three smaller than the dynamic viscosity of the polymer solution without neutralization. The invention further pertains to a process making the same and para-aramid pulp-like fiber, paper and film made from said polymer solution.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.