초록

Robust round homofilament fibers are meltspun from a spinneret having two conjoined capillaries of different length to diameter ratio to induce differential shear to produce fiber crimping. Crimping may further be aided by quenching of the fibers.

대표청구항 ▼

1. A spinneret design for producing a crimped homofilament fiber comprising: a) an extruder for forcing a liquid polymer through spinneret capillaries; b) a fiber forming portion consisting of: i) a counterbore connected to a polymer supply channel, the counterbore longitudinal axis defining

1. A spinneret design for producing a crimped homofilament fiber comprising: a) an extruder for forcing a liquid polymer through spinneret capillaries; b) a fiber forming portion consisting of: i) a counterbore connected to a polymer supply channel, the counterbore longitudinal axis defining a polymer flow axis, the counterbore having a first channel connected to a polymer supply channel and a second channel narrower than the first channel, the second channel connected to the first channel by a first conical feed chamber, the second channel ending in a second conical feed chamber; ii) a first capillary connected to the first conical feed chamber and having an exit hole out of the die head, the first capillary having a length to diameter ratio of between about 6:1 to about 10:1, the first capillary longitudinal axis being parallel to the flow axis; (iii) a second capillary connected between the first capillary at a point prior to the exit hole and the second feed chamber, the second capillary having a length to diameter ratio of about 1.5:1 to achieve a desired crystallinity percentage within the fiber; and whereby liquid polymer extrusions from the first capillary and the second capillary commingle to form a single filament having sections of different induced shear thereby causing the filament to crimp. 2. The spinneret design for producing a crimped homofilament fiber according to claim 1 wherein: the second capillary diameter is only about 1/3 of the first capillary diameter. 3. The spinneret design for producing a crimped homofilament fiber according to claim 1 wherein: the second capillary joins the first capillary at an angle of about 45 degrees to the flow axis. 4. The spinneret design for producing a crimped homofilament fiber according to claim 1 wherein the exit hole is round. 5. The spinneret design for producing a crimped homofilament fiber according to claim 1 wherein: the capillaries are round in a cross section perpendicular to a direction of flow of the capillaries. 6. The spinneret design for producing a crimped homofilament fiber according to claim 1 wherein: the conical feed chambers have walls angled to each other at 60 degrees.