Claims
- 1. A process for producing an acrylonitrile polymer fiber tow having a reversible crimp shrinkage of at least about 12% which comprises preparing separate concentrated aqueous thiocyanate salt solvent spinning solutions of two acrylonitrile polymers containing 1) at least about 85 weight percent acrylonitrile and 2) sulfonic acid groups, one of said polymers containing a sufficient number of sulfonic acid groups to be hydrophilic, the ratio of said sulfonic acid groups of one polymer to those of the other polymer being in the range of 2.1:1 to 9:1, layering the solutions by simultaneously charging them each through opposite sides of a mixing unit at a flow rate that provides a mixture of polymers in the resulting tow in a ratio of about 70:30 to 30:70 of the hydrophilic polymer to the other, said mixing unit being equipped with a number of of flow-reversing cutting elements, charging the resultant layered polymer solutions into a spinnerette having a rectangular or circular shape and a number of orifices such that I is between about 0.4 to about 2.8 as determined by the equation: ##EQU3## wherein the superscript n is the number of cutting elements and K is a constant equal to 1.0 for rectangular spinnerettes and 1.1 for circular spinnerettes to form fibers, charging said fibers into a diluted aqueous thiocyanate salt solution coagulation bath to provide wet-gel filaments, stretching the wet-gel filaments at a total stretch ratio of between about 6 and about 15, inclusive, washing and drying the resultant stretched fibers to provide a tow and treating the tow under heat and humidity conditions sufficient to provide an acrylic fiber bundle having a reversible crimp shrinkage therein of at least about 12%, said filaments comprising A) monocomponent filaments of said hydrophilic polymer, B) monocomponent filaments of said other polymer, C)bicomponent filaments of both of said polymers and D) bicomponent filaments of both of said filaments having an average of about 0.4 to about 2.8 interfaces between polymer components.
- 2. The process of claim 1 wherein the reversible crimp shrinkage is at least about 16%.
- 3. The process of claim 1 wherein the reversible crimp shrinkage is at least about 20%.
- 4. The process of claim 1 wherein the reversible crimp shrinkage is at least about 25%.
- 5. The process of claim 1 wherein the ratio of one polymer to the other is 50:50.
Parent Case Info
This is a divisional of co-pending application, Ser. No. 07/625,409, filed Dec. 11, 1990 now U.S. Pat. No. 5,130,195.
US Referenced Citations (2)
Number |
Name |
Date |
Kind |
3984515 |
Mommaerts et al. |
Oct 1976 |
|
4332762 |
Lynch |
Jun 1982 |
|
Foreign Referenced Citations (1)
Number |
Date |
Country |
330766 |
Sep 1989 |
EPX |
Divisions (1)
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Number |
Date |
Country |
Parent |
625409 |
Dec 1990 |
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