Processes for making poly (trimethylene terephthalate) yarns
AssigneeE. I. Du Pont de Nemours and Company
InventorsJames M. Howell, Joe Forrest London, Jr., Michelle H. Watkins
Life of this patent
Estimating the term…
Abstract
Fine denier poly(trimethylene terephthalate) feed yarns and drawn yarns wherein the drawn yarns are characterized by a denier per filament less than 1.5 and are drawn such that the actual draw ratio is within 10 percent of the predicted draw ratio determined according to: [(elongation to break of the feed yarn)+115]/[(elongation to break of the drawn yarn)+115)].
Claims21
A process for making a drawn yarn from a partially oriented feed yarn, comprising the steps of:
- (1) providing a polyester polymer having an intrinsic viscosity of at least 0.80 dl/g comprising at least 85 mole % poly(trimethylene terephthalate) wherein at least 85 mole % of repeating units consist of trimethylene units
- (2) spinning the polyester polymer by melt-extruding the polyester polymer at a temperature between about 255° C. and 275° C. to form a partially oriented feed yarn;
- and
- (3) preparing a drawn yarn from the partially oriented feed yarn, wherein said drawn yarn has the following characteristics:
- (a) a denier per filament less than about 1.5;
- and
- (b) an actual draw ratio within 10 percent of a predicted draw ratio, wherein the predicted draw ratio is determined according to:
- [(elongation to break of the feed yarn)+115]/[(elongation to break of the drawn yarn)+115].
A process for making a drawn yarn comprising:
- (a) providing partially oriented feed yarn filaments prepared from a polyester polymer having an intrinsic viscosity of at least 0.80 dl/g comprising at least 85 mole % poly(trimethylene terephthalate) wherein at least 85 mole % of repeating units consist of trimethylene units;
- and
- (b) drawing the filaments between a set of feed rolls to produce a denier per filament less than about 1.5 and an actual draw ratio within 10 percent of a predicated draw ratio, wherein the predicted draw ratio is determined according to:
- [(elongation to break of the feed yarn)+115]/[(elongation to break of the drawn yarn)+115].
A process of preparing a fine denier partially oriented undrawn feed yarn made from a polyester polymer melt-extruded at a spinning temperature between about 255° C. and about 275° C., wherein said polymer comprises at least 85 mole % poly(trimethylene terephthalate) wherein at least 85 mole % of repeating units consist of trimethylene units, and wherein said polymer has an intrinsic viscosity of at least 0.80 dl/g, and wherein said partially oriented undrawn fine denier feed yarn has a denier per filament less than about 2.
Dependencies are inferred from the claim text.