Lin-Fa Lee

US Patent:

40599493, Nov 29, 1977

Filed:

Sep 2, 1976

Appl. No.:

5/719954

Inventors:

Lin-Fa Lee - Chattanooga TN

Assignee:

E. I. Du Pont de Nemours and Company - Wilmington DE

International Classification:

D02G 304

US Classification:

57140BY

Abstract:

A composite yarn exhibiting heather dyeing capability is comprised of two groups of filaments composed of two differently dyeable polymers wherein filaments of one group are homofilaments of one polymer and filaments of the other group are of a substantially concentric sheath core structure with the sheath being of the other polymer and the core being of the same polymer as the homofilaments. The yarn dyes to give a heather appearance which is different from the appearance expected based on the polymer composition of the yarn.

US Patent:

52846121, Feb 8, 1994

Filed:

Nov 23, 1992

Appl. No.:

7/977687

Inventors:

Lin-Fa Lee - Chattanooga TN

Assignee:

E. I. Du Pont de Nemours and Company - Wilmington DE

International Classification:

B29C 4788
D01D 512
D01D 1002
D02J 122

US Classification:

2642108

Abstract:

A coupled process for making partially-oriented polyamide yarn. Polyamide polymer is melt-spun at a withdrawal speed sufficient to produce a spun yarn having an elongation less than 175%. The spun yarn is subsequently subjected to a coupled drawing step in a draw zone to reduce the elongation to the range of 50 to 100%. In the draw zone, the yarn passes through an enclosure with a gaseous fluid jet having a temperature of at least about 190. degree. C. which impinges on the yarn in an intersecting relationship to the path of yarn travel.

US Patent:

39924998, Nov 16, 1976

Filed:

Feb 15, 1974

Appl. No.:

5/442905

Inventors:

Lin-Fa Lee - Chattanooga TN

Assignee:

E. I. Du Pont de Nemours and Company - Wilmington DE

International Classification:

D01F 104
B29F 310

US Classification:

264 78

Abstract:

In cospinning two fiber-forming polymers to produce a composite heather yarn from filaments of different dyeability, the apparent weight ratio of one polymer in the yarn can be varied by spinning only a portion of that polymer as a monocomponent filament and hiding the remainder as the core of a sheath-core filament having the other polymer as its sheath. Thus, a wide range of apparent weight ratios of the two polymers in the cospun yarn is provided, without changing the flow rate of the two polymer solutions fed to the spinneret.