Method of producing polyvinyl chloride fibers having improved thermal properties

Claim 1

A METHOD OF PRODUCING POLYVINYL CHLORIDE FIBERS, WHEREIN THERE IS EMPLOYED AS A STARTING MATERIAL A POLYVINYL CHLORIDE POLYMER CONTAINING AT LEAST 90 MOL PERCENT OF VINYL CHLORIDE, SAID POLYVINYL CHLORIDE POLYMER HAVING A D1426/D1434 VALUE OF INFRARED ABSORPTION, AS DEFINED, OF 1.08 TO 1.27, A POLYMERIZATION DEGREE OF BETWEEN 500 AND 2500, AND AN APPARENT SPECIFIC GRAVITY OF LESS THAN 0.2G./CM.3, SAID POLYVINYL CHLORIDE BEING OBTAINED BY POLYMERIZING VINYL CHORIDE AT A LOW TEMERATURE RANGING FROM 20*C. TO -50*C., WHICH METHOD COMPRISES HEATING SAID POLYVINYL CHLORIDE AT A TEMPERTURE ABOVE THE SOFTENING TEMPERATURE AT WHICH THE THERMAL MOTION OF THE MOLECULES BECOME ACTIVE WHEREBY STABILIZATION OF THE FINE STRUCTURE OCCURS, BUT BELOW THE DECOMPOSITION TEMPERATURE OF SAID POLYMER, THEREBY INCREASING THE APPARENT SPECIFIC GRAVITY OF THE POLYVINYL CHLORIDE TO 0.3G./CM.3 TO 0.6G./CM.3, MIXING PARTICLES OF SAID HEATTREATED POLYVINYL CHLORIDE POLYMER WITH A SOLVENT THEREFOR, THEREBY SWELLING THE PARTICLES AND FORMING A FLUID, STABLE, SWOLLEN MIXTURE WITH SMALL CHANGE IN THE VISCOSITY THEREOF, HEATING THE SWOLLEN MIXTURE THEREBY PROVIDING A UNIFORM SOLUTION OF SAID SWOLLEN MIXTURE, AND FINALLY EXTRUDING THE SOLUTION.

Claim 2

A METHOD OF PRODUCING POLYVINYL CHLORIDE FIBERS, WHEREIN THERE IS EMPLOYED AS A STARTING MATERIAL A POLYVINYL CHLORIDE POLYMER CONTAINING AT LEAST 90 MOL PERCENT OF VINYL CHLORIDE, SAID POLYVINYL CHLORIDE POLYMER HAVING A D1426/D1434 VALUE OF INFRARED ABSORPTION, AS DEFINED, OF 1.08 TO 1.27, A POLYMERIZATION DEGREE OF BETWEEN 500 AND 2500, AND AN APPARENT SPECIFIC GRAVITY OF LESS THAN 0.2G./CM.3, SAID POLYVINYL CHLORIDE BEING OBTAINED BY POLYMERIZING VINYL CHORIDE AT A LOW TEMERATURE RANGING FROM 20*C. TO -50*C., WHICH METHOD COMPRISES HEATING SAID POLYVINYL CHLORIDE AT A TEMPERTURE ABOVE THE SOFTENING TEMPERATURE AT WHICH THE THERMAL MOTION OF THE MOLECULES BECOME ACTIVE WHEREBY STABILIZATION OF THE FINE STRUCTURE OCCURS, BUT BELOW THE DECOMPOSITION TEMPERATURE OF SAID POLYMER, THEREBY INCREASING THE APPARENT SPECIFIC GRAVITY OF THE POLYVINYL CHLORIDE TO 0.3G./CM.3 TO 0.6G./CM.3, MIXING PARTICLES OF SAID HEATTREATED POLYVINYL CHLORIDE POLYMER WITH A SOLVENT THEREFOR, THEREBY SWELLING THE PARTICLES AND FORMING A FLUID, STABLE, SWOLLEN MIXTURE WITH SMALL CHANGE IN THE VISCOSITY THEREOF, HEATING THE SWOLLEN MIXTURE THEREBY PROVIDING A UNIFORM SOLUTION OF SAID SWOLLEN MIXTURE, AND FINALLY EXTRUDING THE SOLUTION.