Process for the expeditious formation and structural modification of polyester fibers

An improved process for expeditiously forming and structurally modifying polyester filamentary material consisting essentially of:

• a. extruding a molten fiber-forming polyester capable of undergoing crystallization containing at least 85 mol percent of polyethylene terephthalate through a spinneret to form a molten filamentary material,
• b. passing the resulting molten polyester filamentary material in the direction of its length through a solidification zone provided with a gaseous atmosphere at a temperature below 80.degree.C. wherein said molten polyester filamentary material is uniformly quenched and is transformed to a solid filamentary material,
• c. passing said resulting filamentary material in the direction of its length through a conditioning zone provided with a gaseous atmosphere at a temperature of about 90.degree. to 180.degree.C. for a residence time of about 0.0016 to 0.6 second wherein substantial crystallization of said previously solidified filamentary material takes place, and
• withdrawing the resulting filamentary material from said conditioning zone at a rate of about 2500 to 6000 meters per minute while under a stress of about 0.1 to 1.0 gram per denier;
• said resulting filamentary material exhibiting no substantial tendency to undergo self-crimping upon the application of heat, exhibiting a mean tenacity of at least 3.75 grams per denier, a mean initial modulus of at least 75 grams per denier, and a mean elongation of 50 percent or less when present in a multifilament yarn at 25.degree.C., and exhibiting a mean longitudinal yarn shrinkage of less than 5 percent when present in a multifilament yarn at 100.degree.C.;
• with said processing of said filamentary material following said extrusion being conducted while exerting a constant tension thereon in the absence of stress isolation along the length of the same intermediate said spinneret and said point of withdrawal from said conditioning zone.

An improved process for expeditiously forming and structurally modifying polyethylene terephthalate filamentary material consisting essentially of:

• a. extruding molten fiber-forming polyethylene terephthalate at a temperature of about 270.degree. to 310.degree.C. through a spinneret,
• b. passing the resulting molten polyethylene terephthalate filamentary material in the direction of its length through a solidification zone provided with a gaseous atmosphere at a temperature below 80.degree.C. wherein said extruded polyethylene terephthalate filamentary material is uniformly quenched and is transformed to a solid filamentary material,
• c. passing the resulting filamentary material in the direction of its length through a conditioning zone provided with a gaseous atmosphere at a temperature of about 100.degree. to 140.degree.C. for a residence time of about 0.0016 to 0.6 second, and
• d. withdrawing the resulting filamentary material from said conditioning zone at a rate of about 2500 to 3500 meters per minute while under a stress of about 0.15 to 0.6 gram per denier;
• said resulting filamentary material exhibiting no substantial tendency to undergo self-crimping upon the application of heat, exhibiting a mean tenacity of at least 3.75 grams per denier, a mean initial modulus of at least 75 grams per denier, and a mean elongation of 50 percent or less when present in a multifilament yarn at 25.degree.C., and exhibiting a mean longitudinal yarn shrinkage of less than 5 percent when present in a multifilament yarn at 100.degree.C.;
• with said processing of said filmentary material following said extrusion being conducted while exerting a constant tension thereon in the absence of stress isolation along the length of the same intermediate said spinneret and said point of withdrawal from said conditioning zone.

An improved process for expeditiously forming and structurally modifying a flat polyethylene terephthalate yarn which exhibits no substantial tendency to undergo self-crimping upon the application of heat consisting essentially of:

• a. extruding molten fiber-forming polyethylene terephthalate at a temperature of about 300.degree.C. through a spinneret containing about 6 to 200 extrusion holes having a diameter of about 10 to 60 mils,
• b. passing the resulting molten polyethylene terephthalate material in the direction of its length through a solidification zone provided with an air atmosphere at about 10.degree. to 40.degree.C. wherein said extruded polyethylene terephthalate material is uniformly quenched and is transformed to a solid multifilament yarn,
• c. passing the resulting yarn in the direction of its length through a conditioning zone provided with a gaseous atmosphere at about 110.degree. to 120.degree.C. for a residence time of about 0.03 to 0.09 second, and
• d. withdrawing the resulting yarn having a denier per filament of about 1 to 10 from said conditioning zone at a rate of about 2500 to 3500 meters per minute while under a stress of about 0.2 to 0.4 gram per denier;
• said resulting filamentary material exhibiting a mean tenacity of at least 3.75 grams per denier, a mean initial modulus of at least 75 grams per denier, and a mean elongation of 50 percent or less when present in a multifilament yarn at 25.degree.C., and exhibiting a mean longitudinal yarn shrinkage of less than 5 percent when present in a multifilament yarn at 100.degree.C.;
• with said processing of said yarn following said extrusion being conducted while exerting a constant tension thereon in the absence of stress isolation along the length of the same intermediate said spinneret and said point of withdrawal from said conditioning zone.