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US 5,294,707 AGranted
Semi-continuous depolymerization of nylon 6 polymer
AssigneeBASF SE
InventorRichard Kotek
Life of this patent
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Abstract
Polyamide is semi-continuously depolymerized by: (a) charging the polyamide to a depolymerization reactor containing 5 to 50% by weight of an unpolymerized catalyst; (b) melting the polyamide and subjecting the resultant melt to a flow of superheated steam to obtain a steam distillate; (c) separating amide monomers in the distillate from other volatiles therein; (d) when conversion to amide monomers is 40 to 90% complete, recharging polyamide to the depolymerization reactor; and (e) repeating steps (a)-(d) until a desired amount of polyamide is depolymerized.
Claims8
A process for the semi-continuous depolymerization of nylon 6 comprising:
- (a) charging nylon 6 to a depolymerization reactor containing 5 to 50% by weight of unpolymerized catalyst;
- (b) melting the nylon 6 and subjecting the resultant melt to a flow of superheated steam to obtain a stream distillate;
- (c) separating caprolactam monomers in the distillate from other volatiles therein;
- (d) when conversion to caprolactam is 40 to 90% complete, recharging nylon 6 to the depolymerization reactor;
- and
- (e) repeating steps (a)-(d) until a desired amount of nylon 6 is converted to caprolactam.
3 more elements
Dependencies are inferred from the claim text.