Thermoplastic nonwoven using melt blown fibres

摘要

A continuous nonwoven of thermoplastic polymer filaments which can exist in crystalline and amorphous states is made by producing long filaments in a melt blowing head with a number of spinneret holes interacting with flat compressed air jets. The blowing conditions are selected to give filaments of less than 100 microns with less than 45% crystallinity. The filaments are deposited on a continuously moving sieve so that the filaments bond at their crossing points to produce an intermediate product. The intermediate product is heated to drawing temperature and drawn 100 - 400% longitudinally and transversely, i.e. biaxially. It is then heat set at a higher temperature. The drawing and setting conditions are arranged to give at least 50% crystallinity.