Patent ID: 7152390

Claim:
A process for making a yarn having a spandex core covered tightly with a nylon fiber, comprising: i) providing a highly shrinkable nylon fiber having a shrinkage in boiling water at least 20%; ii) providing a spandex fiber having a thickness from 11 dtex to 400 dtex; iii) wrapping said spandex fiber with said nylon fiber using a standard covering method, thereby obtaining a composite yarn consisting of a spandex core with a high shrinkage wrapping; and iv) heat-treating said composite yarn, without stretching it, at a temperature from 85 to 105° C.; thereby obtaining a yarn consisting of a spandex fiber wrapped tightly with an initially highly shrinkable nylon fiber, wherein the heat-treating may be performed before or after said composite yarn is used in preparation of a fabric.