Crimping of yarns based on thermoplastic polymers

Claim 1

PROCESS FOR THE PRODUCTION OF CRIMPED YARNS OF THERMOPLASTIC POLYMERS WHICH COMPRISES PASSING A FIRST YARN AND A SECOND YARN THROUGH A COMPRESSED FLUID FEED JET, THE SAID FIRST YARN BEING OF A THERMOPLASTIC POLYMER AND BEING FED AT A RATE GREATER THAN SAID SECOND YARN, THE SAID FIRST YARN AND SECOND YARN BEING SUBJECTED IN THE COMPRESSED FLUID FEED JET TO THE ACTIN OF A TURBULENT FLUID, THEREBY PRODUCING A COMPOSITE MOCK-BOUCLE YARN IN WHICH THE SAID FIRST YARN CONSTITUTES A PERIPHERAL YARN IN WHICH THE INDIVIDUAL FILAMENTS HAVE A RANDOM, NONPERIODIC CRIMP AND THE SAID SECOND YARN CONSTITUTES A CORE YARN; AND, AFTER SETTING THE CRIMP IN THE SAID PERIPHERAL YARN, REMOVING THE CORE YARN, LEAVING A CRIMPED SET YARN OF THE THERMOPLASTIC POLYMER.