Synthetic fibers having a natural crimp and method for preparing the same

Claim 1

A PROCESS FOR PREPARING HOLLOW FIBERS HAVING A NATURAL CRIMP FROM POLYMERIC MATERIALS COMPRISING AS SEQUENTIAL STEPS THE CONTINUOUS CONTACTING IN FIBER-FORMING RELATIONSHIP OF A LATEX CONTAINING AT LEAST 25 PERCENT BY WEIGHT OF POLYMERIC SOLIDS OF A NORMALLY CRYSTALLINE VINYLIDENE CHLORIDE POLYMER, WITH AN AQUEOUS COAGULANT SOLUTION COMPRISING COAGULATIVE AMOUNTS OF AN ELECTROLYTE COAGULANT FOR SAID LATEX AND FIBER-FORMING AMOUNTS OF A POLYMERIC MATERIAL DISSIMILAR IN ORIENTATION CHARACTERISTICS TO SAID POLYMER OF SAID LATEX TO FORM A COAXIAL FILAMENTARY COAGULUM HAVING ONE POLYMERIC MATERIAL AS A CORE AND THE OTHER AS A SHEATH, REMOVING SAID FILAMENTARY COAGULUM FROM THE POINT AT WHICH IT IS FORMED AT THE SAME RATE AT WHICH IT IS FORMED, WASHING SAID FILAMENTARY COAGULUM TO REMOVE SUBSTANTIALLY ALL OF SAID ELECTROLYTE COAGULANT. DRYING SAID FILAMENTARY COAGULUM AT A RATE AND UNDER CONDITIONS THAT ANY DISPERSANT FOR SAID CORE POLYMERIC IS CAUSED TO DIFFUSE THROUGH THE PLOYMER SHEATH TO DEPOSIT A CONTINUOUS COATING OF SAID CORE POLYMERIC MATERIAL ON THE INNER SURFACE OF SAID POLYMER SHEATH FUSING SAID FILAMENTARY COAGULUM TO FORM A CONTINUOUSM HOLLOW FIBER, SUPERCOOLING SAID FIBER, AND STRECHING SAID FIBER BEYOND THE ELASTIC LIMIT TO PRODUCED ORENTATION THEREIN.