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US 4,379,773 AGranted
Process for wet spinning nylon 4
AssigneeChevron Research Company
InventorsMitchell Danzik, J. Ronald Carpenter
Life of this patent
Estimating the term…
Abstract
Processes for wet spinning nylon 4 filaments. The processes are characterized by the use of a formic acid spinning dope and an acidic aqueous alkali metal formate coagulation bath maintained at elevated temperatures.
Claims18
A wet spinning process, for wet spinning nylon 4 filaments, which comprises the steps of:
- (a) extrusion wet spinning a spinnable solution of nylon 4 dissolved in a solvent containing about from 60 to 100 wt % formic acid and about from 40 to 0 wt % water into an acidic aqueous coagulation bath containing a nylon 4 coagulation effective amount of alkali metal formate selected from the group consisting of sodium formate, potassium formate, lithium formate and mixtures thereof, and about from 6 to 30 wt %, formic acid, for a sufficient time to coagulate said spun nylon 4 solution into filaments and wherein said coagulation bath is maintained at temperatures in the range of about from 35.degree. C. up to the boiling point of said coagulation bath;
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- (b) collecting said filaments.
A wet spinning process comprising the steps of:
- (a) spinning a spinning dope, consisting essentially of a 60 to 85 weight percent aqueous formic acid solution of a fiber forming nylon 4 polymer, into a 40 to 70 weight percent aqueous alkali metal formate coagulation bath having a formic acid concentration in the range of about from 6 to 30 weight percent and maintained at about from 35.degree. C. up to the boiling point of said coagulation bath, whereby filaments of said nylon 4 coagulate and formic acid diffuses into said bath from the spun dope;
- (b) removing at least a portion of said bath when its formic acid concentration is in the range of about from 20 to 30 wt %;
- (c) regenerating the removed portion of said bath by removing the major portion of said formic acid therefrom and recycling the regenerated bath back to said coagulation bath.
Dependencies are inferred from the claim text.