Needled felts for filters of bilaminar polypropylene fibres - are heat treated to inter-hook previously crimped filaments

摘要

Bilamellate fibres are mixed mechanically and laid on the surface of a carrier and the fibres are the subjected to a thermal treatment so that the pretreated fibres, on account of their crimp, which was produced by heating, hook into each other, forming a felt, which is used as a filter element. Used to produce a dense felt without it being necessary to effect a mechanical entanglement of the fibres so that the filter element has a high degree of tenacity. The fibres used are rectilinear, rectangular, bilamellate fibres produced in FR 75 11489 of 10.4.75.