Polyester fine filaments
AssigneeE. I. Du Pont de Nemours and Company
InventorsRobert J. Collins, Hans R. E. Frankfort, Stephen B. Johnson, Benjamin H. Knox, Elmer E. Most, Jr.
Life of this patent
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Abstract
Polyester fine filaments having excellent mechanical quality and uniformity, and preferably with a balance of good dyeability and shrinkage, are prepared by a simplified direct spin-orientation process by selection of polymer viscosity and spinning conditions.
Claims12
Yarns comprising fine polyester filaments of denier per filament (dpf) in the range 0.2 to 0.8, said polyester having a relative viscosity (LRV) in the range 13 to 23, a zero-shear polymer melting point (T.sub.M.sup.o) in the range 240.degree. C. to 265.degree. C., and a glass transition temperature (T.sub.g) in the range 40.degree. C. to 80.degree. C.;
- and said yarns having the following characteristics:
- (a) tenacity-at-7%-elongation (T.sub.7) in the range 0.5 to 1.75 gpd, such that the [(T.sub.B).sub.n /(T.sub.7)]-ratio is at least [5/(T.sub.7)], wherein (T.sub.B).sub.n is normalized tenacity-at-break;
- (b) elongation-at-break (E.sub.B) in the range 40% to 160%;
- (c) boil-off shrinkage (S) less than the maximum shrinkage potential (S.sub.m), wherein Sm=[(550-E.sub.B)/6.5]%;
- (d) maximum shrinkage tension (ST.sub.max) in the range 0.05 to 0.2 gpd, with a peak temperature T(ST.sub.max) in the range 5.degree. C. to 30.degree. C. above the glass-transition temperature (T.sub.g)
- (e) an average along-end filament denier spread (DS) of no more than 4%.
Yarns comprising fine polyester filaments of denier per filament (dpf) after boil-off shrinkage in the range 0.2 to 0.8 dpf, said polyester having a relative viscosity (LRV) in the range 13 to 23, a zero-shear polymer melting point (T.sub.M.sup.o) in the range 240.degree. C. to 265.degree. C., and a glass-transition temperature (T.sub.g) in the range 40.degree. C. to 80.degree. C.;
- and said yarns having the following characteristics:
- (i) boil-off shrinkage (S) and dry heat shrinkage (DHS) in the range of 2% to 12%;
- (ii) Tenacity-at-7%-elongation (T.sub.7) at least 1 gpd, such that the [(T.sub.B)n/(T.sub.7)]-ratio is at least [5/(T.sub.7)], wherein (T.sub.B)n is normalized tenacity-at-break, and elongation-at-break (E.sub.B) in the range 15% to 55%;
- (iii) post-yield modulus (M.sub.py) in the range 5 to 25 gpd;
- (iv) an average along-end filament denier spread (DS) no more than 4%.
Yarns comprising fine polyester filaments of denier per filament (dpf) in the range 0.2 to 0.8 dpf, after boil-off shrinkage, said polyester having a relative viscosity (LRV) in the range 13 to 23, a zero-shear polymer melting point (T.sub.M.sup.o) in the range 240.degree. C. to 265.degree. C., and a glass-transition temperature (T.sub.g) in the range 40.degree. C. to 80.degree. C.;
- said yarns being bulky and having the following characteristics:
- (i) boil-off shrinkage (S) and dry heat shrinkage (DHS) in the range of 2% to 12%;
- (ii) tenacity-at-7%-elongation (T.sub.7) greater than 1 gpd, E.sub.B in the range 15% to 55% and post-yield modulus (M.sub.py) in the range 5 to 25 gpd.
Dependencies are inferred from the claim text.