Stock material or miscellaneous articles – Pile or nap type surface or component – Composition of pile or adhesive
Reexamination Certificate
1998-09-01
2001-07-03
Morris, Terrel (Department: 1771)
Stock material or miscellaneous articles
Pile or nap type surface or component
Composition of pile or adhesive
C428S085000
Reexamination Certificate
active
06254961
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to the spinning of synthetic polymeric yarns. In a specific embodiment, the invention relates to spinning poly(trimethylene terephthalate) into yarn suitable for carpets.
Polyesters prepared by condensation polymerization of the reaction product of a diol with a dicarboxylic acid can be spun into yarn suitable for carpet fabric. U.S. Pat. No. 3,998,042 describes a process for preparing poly(ethylene terephthalate) yarn in which the extruded fiber is drawn at high temperature (160° C.) with a steam jet assist, or at a lower temperature (95° C.) with a hot water assist. Poly(ethylene terephthalate) can be spun into bulk continuous filament (BCF) yarn in a two-stage drawing process in which the first stage draw is at a significantly higher draw ratio than the second stage draw. U.S. Pat. No. 4,877,572 describes a process for preparing poly(butylene terephthalate) BCF yarn in which the extruded fiber is drawn in one stage, the feed roller being heated to a temperature 30° C. above or below the Tg of the polymer and the draw roller being at least 100° C. higher than the feed roll. The application of conventional polyester spinning processes to prepare poly(trimethylene terephthalate) BCF results in yarn which is of low quality and poor consistency. It would be desirable to have a process for preparing high-quality BCF carpet yarn from poly(trimethylene terephthalate).
It is therefore an object of the invention to provide a process for preparing high-quality bulk continuous filament yarn from poly(trimethylene terephthalate).
SUMMARY OF THE INVENTION
According to the invention, poly(trimethylene terephthalate) is formed into a bulk continuous filament yarn by a process comprising:
(a) melt-spinning poly(trimethylene terephthalate) at a temperature within the range of about 240° to about 280° C. to produce a plurality of spun filaments;
(b) cooling the spun filaments;
(c) converging the spun filaments into a yarn;
(d) drawing the yarn at a first draw ratio within the range of about 1.01 to about 2 in a first drawing stage defined by at least one feed roller and at least one first draw roller, each of said at least one feed roller operated at a temperature less than about 100° C. and each of said at least one draw roller heated to a temperature greater than the temperature of said at least one feed roller and within the range of about 50 to about 150° C.;
(e) subsequently drawing the yarn at a second draw ratio of at least about 2.2 times that of the first draw ratio in a second drawing stage defined by said at least one first draw roller and at least one second draw roller, each of said at least one second draw roller heated to a temperature greater than said at least one first draw roller and within the range of about 100 to about 200° C.; and
(f) winding the drawn yarn.
The process may optionally include texturing the drawn yarn prior to or after winding step (f).
The process of the invention permits the production of poly(trimethylene terephthalate) bulk continuous filament yarn suitable for high-quality carpet.
REFERENCES:
patent: 5645782 (1997-07-01), Howell et al.
patent: 5662980 (1997-09-01), Howell et al.
Morris Terrel
Pratt Christopher C.
Shell Oil Company
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