E.i. Dupont De Nemours and Company

Stanley R Cochran

Hung H Yang

Oren Hardin Davis

Francis W Strahorn

Aromatic polyamide filaments of higher strength are obtained by drying air-gap spun filaments under tension while controlling the moisture content of the dried filaments.

Yarn drying process

Aromatic polyamide filaments are treated at high speed under tension by passage over an array of closely spaced, heated rolls at 175.degree.-300.degree. C., the filaments stretched 0-1.6% and passed over a second array of additional closely spaced, heated rolls at 175.degree.-300.degree. C., cooled and wound up.

Yarn heat treatment apparatus

A process and apparatus for producing thick and thin filaments wherein the deniers of the thick portions of the filaments are randomized by passing an undrawn nylon feed yarn from a supply package under tension through the nip in a feed/cott roll combination, the cott roll having at least one peripheral slot periodically opening the nip. The yarn is forwarded from this nip by a draw roll assembly operated at a peripheral velocity of 3-5X that of the feed roll to fully draw the drawn portions. A snubbing device is used upstream of the feed/cott roll assembly to provide a yarn tension immediately upstream of the nip.

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Midlothian, VA, United States of America

Stanley R Cochran