Synthetic yarn and yarn-like structures and a method for their production

Abstract

Synthetic yarn and yarn-like structures are formed by the method of treating separate multifilament strands of thermoplastics material so that at least one has a shrinkage ratio higher than normal at an elevated temperature. The strands are intermingled in a gas stream with formation of loops on the strands after which they are subjected to a twisting force which imparts a random form of twist on the intermingled formation followed by a heating operation to cause them to shrink differentially while being held until shrinkage ceases so that interlocking bud-like projections form on the filaments. Apparatus for performing the method includes yarn drawing means, intermingling means comprising a jet device incorporating intersecting passages for the strands and for a gas under pressure, means arranged to apply a twisting force to the intermingled filaments, feeding means and heating and cooling means for the intermingled yarn incorporating twist downstream from the jet device, also means for holding the yarn to a predetermined length while it is being heated and cooled.