Aramid fibrils
US7629047B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 30, 2004 |
| Grant date | Dec 8, 2009 |
| Priority date | — |
| Expiry date | Dec 11, 2025 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/2969
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
Aramid fibrils having in the wet phase a Canadian Standard Freeness (CSF) value less than 100 ml, after drying a specific surface area (SSA) less than 7 m2/g, and a weight weighted length for particles having a length >250 μm (WL 0.25) less than 1.2 mm, are described. A method of preparing the fibrils includes the steps (a) polymerizing an aromatic diamine and an aromatic dicarboxylic acid halide to an aramid polymer, in a mixture of N-methylpyrrolidone or dimethylacetamide and calcium chloride or lithium chloride to obtain a dope wherein the polymer is dissolved in the mixture and the polymer concentration is 2 to 6 wt. %, (b) converting the dope to fibrils by using a jet spin nozzle under a gas stream, and (c) coagulating the fibrils using a coagulation jet.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.