Steam drawing of polyester monofilament to improve loop strength and resistance to fibrillation

摘要

There is provided a method of improving the properties of polyester monofilaments in respect to loop strength and resistance to fibrillation. The process contemplates treating an undrawn substantially noncrystalline extensible spun linear polyethylene terephthalate monofilament with a vapor medium such as steam and, while the monofilament is exposed to such vapor, drawing the monofilament at a draw ratio of from 1.5:1 to 4:1 and further drawing the monofilament in a subsequent drawing operation to an aggregate draw ratio of from 4:1 to 10:1.PPThe process enables development of the maximum or a desired loop strength value for the particular monofilament being processed with optimization of specific drawing conditions such as the steam pressure within the indicated draw ratios. Thus, drawn monofilaments having loop strength values of at least 2.5 grams/denier are provided, and the drawn products are particularly useful as reinforcing elements in rubber bodies, e.g. tire cords.