TREATED POLYMERIC NON-WOVEN FABRIC

摘要

A polymeric sheet, which is particularly suited for use as a separator in an electrochemical device, is formed by graft copolymerising acrylic acid, or another vinyl monomer capable of reacting with an acid or a base to form a salt directly or indirectly with fibres of a non-woven sheet, whose outer surface is provided by a polyolefin, especially polypropylene. The polyolefin is crosslinked as a result of the polymerisation reaction. The polymerisation reaction is preferably initiated by exposure of the sheet to ultraviolet radiation, after impregnation with an appropriate solution of the vinyl monomer.