Aramid fibrils
2Aramid 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 m/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 fi...
Gespeichert in:
Hauptverfasser: | , , , , |
---|---|
Format: | Patent |
Sprache: | eng |
Online-Zugang: | Volltext bestellen |
Tags: |
Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
|
Zusammenfassung: | 2Aramid 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 m/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. |
---|