摘要 |
<p>The invention relates to synthetic yarn and yarn-like structures. …<??>Separate strands (1, 2, 3) of thermoplastic material are treated so that at least one (2, 3) has a shrinkage ratio higher than normal at an elevated temperature. The strands are intermingled in a gas stream with formation of loops (21) on the strands, then heated to cause them to shrink differentially while being held to a predetermined length, then cooled while being held until shrinkage ceases. Apparatus for performing the method includes yarn drawing means (7, 8, 9) intermingling means comprising a jet device (10) incorporating intersecting passages (11, 12) for the strands and for a gas under pressure, feeding means (4, 5, 6) and heating (16) and cooling (19) means for the intermingled yarn downstream from the jet device, also means (16, 17 and 17, 18) for holding the intermingled yarn to a predetermined length while it is being heated and cooled. …<??>The yarn produced is flexible, of uniform cross section and shows no tendency for the strands to separate.</p> |