Heat bulkable polyester yarn and method of forming same

摘要

The present invention relates to a process and product for directly producing a latent heat-bulkable yarn from the same polymer composition in the same spinning process. The self-crimping yarn is produced from polyethylene terephthalate compositions which are melt spun at high speeds to form a plurality of spin oriented filaments. The filaments are divided in the spinning column into at least two groups and the two groups of filaments are subjected to different heat conditions, recombined, and taken up as a fully drawn yarn. The high spinning speed and differential heat treatment are selected to produce highly spin oriented yarn of relatively high spun birefringence with the conditions of spinning speed and heat treatment being controlled to produce a desired shrinkage differential between the two groups of filaments of up to 60 percent. The yarn is self-crimped by subsequent heat treatment to effect shrinkage, preferably after being formed into fabric, such as occurs in the hot dyeing and/or scouring of the fabric.