Claims
- 1. In a process for producing endless, drawn, multiple filaments from filament-forming thermoplastic polymers embodying the steps of extruding a plastic, thermoplastic polymer composition in the form of a foil having a plurality of strand-forming longitudinal rib segments connected by thin, longitudinal necks or strips to form longitudinal, breaking lines or zones, drawing said foil upon or immediately after extrusion by conducting the extruded foil over rotating cylinders operating at speeds sufficient to stretch said extruded foil by at least several times its original length, and immediately cooling the drawn foil sufficiently to solidify said foil, the improvement comprising breaking said solidified foil into completely separated filaments along said breaking lines or zones by the steps consisting of stretching said solidified foil between two sets of rollers, each set having a plurality of rollers over which said foil is conducted in an undulating path on each respective set, and causing said solidified foil to split along said breaking lines or zones into completely separated filaments corresponding to said rib segments solely by the step of imparting a sufficient amount of longitudinal stretching to the solidified foil to separate completely said rib segments into filaments.
- 2. A process as claimed in claim 1 wherein the extruded foil has a width of less than 48 mm and a width to mean thickness ratio of at least 10:1.
- 3. A process as claimed in claim 1, and the further improvement wherein said stretching of the solidified foil is sufficient to cause molecular orientation of the polymer.
- 4. A process as claimed in claim 1, and the further improvement wherein said foil, immediately after extrusion thereof, is stretched longitudinally between 5 and 20 times its original length.
- 5. A process as claimed in claim 1, and the further improvement of heating said foil in the zone between said sets of rollers while stretching said foil at least twice its feed length.
- 6. A process as claimed in claim 1, and the further improvement wherein said cooling includes directing a stream of cooling air against said foil immediately after extrusion thereof.
- 7. A process as claimed in claim 1, and the further improvement wherein said longitudinal rib segments have a polygonal transverse cross section.
- 8. A process as claimed in claim 1, and the further improvement wherein said longitudinal rib segments have a triangular, rectangular, or trapezoidal transverse cross-section.
- 9. A process as claimed in claim 1, and the further improvement wherein said solidified foil is split along said breaking lines or zones into said completely separated filaments upon running of said foil over the second set of rollers.
- 10. In a process for producing endless, drawn, multiple filaments from filament-forming thermoplastic polymers embodying the steps of extruding a plastic, thermoplastic polymer composition in the form of a foil having a plurality of strand-forming longitudinal rib segments connected by thin, longitudinal necks or strips to form longitudinal, breaking lines or zones, drawing said foil upon or immediately after extrusion by conducting the extruded foil over rotating cylinders operating at speeds sufficient to stretch said extruded foil by at least several times its original length, and immediately cooling the drawn foil sufficiently to solidify said foil, the improvement comprising breaking said solidified foil into completely separated filaments along said breaking lines or zones by the steps consisting of stretching said solidified foil between two sets of rollers, each set having a plurality of rollers over which said foil is conducted in an undulating path on each respective set, and causing said solidified foil to split along said breaking lines or zones into completely separated filaments corresponding to said rib segments solely by the steps of imparting a sufficient amount of longitudinal stretching to the solidified foil and also deflecting the solidified foil laterally one or more times in its plane of travel during the longitudinal stretching thereof to separate completely said rib segments into filaments.
Priority Claims (2)
Number |
Date |
Country |
Kind |
B 91793 |
Apr 1967 |
DT |
|
B 92161 |
Apr 1967 |
DT |
|
RELATED APPLICATIONS
This application is a continuation of application Ser. No. 14,758, filed Feb. 25, 1970, now abandoned, which in turn is a continuation of application Ser. No. 665,443, filed Sept. 5, 1967, now abandoned.
US Referenced Citations (13)
Foreign Referenced Citations (4)
Number |
Date |
Country |
265,985 |
Nov 1963 |
AU |
726,766 |
Jun 1932 |
FR |
1,369,155 |
Dec 1964 |
FR |
38-12366 |
Jul 1963 |
JA |
Continuations (2)
|
Number |
Date |
Country |
Parent |
14758 |
Feb 1970 |
|
Parent |
665443 |
Sep 1967 |
|