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...

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Bibliographische Detailangaben
Hauptverfasser: Hendriks, Anton Johannes Josef, Tiecken, Jan Davis Cornelis, Grotendorst, Harrie, Journee, René, Oldenzeel, Mirjam Ellen
Format: Patent
Sprache:eng
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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.