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US 5,403,910 AGranted
Low temperature nylon polymerization process
AssigneeE. I. Du Pont de Nemours and Company
InventorsLeonard E. R. Kosinski, Richard R. Soelch
Life of this patent
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Abstract
A low temperature process for polymerizing nylon monomers to freely flowing polymers is disclosed. The polymerization process is carried out at lower than conventional polymerization temperatures and produces a freely flowing polymer without thermal degradation.
Claims10
A process for the preparation of free flowing polyamides which process comprises the steps of:
- a) polymerizing initial materials comprising an oxygen free equimolar salt of a dicarboxylic, acid and a diamine, under conditions such that the reacting materials never completely liquify, at reaction temperatures below the melting transition temperatures of the initial materials, any intermediate condensation products and any end products,
- 1) in an oxygen-free environment,
- 2) at essentially atmospheric pressure,
- 3) supplying amine, amines, or carboxylic acids, in an amount sufficient to balance acid and amine ends,
- 4) under an inert gas atmosphere,
- 5) while agitating, to produce a freely flowing solid prepolyamide;
- and
- b) further polymerizing the solid prepolyamide of step a) to a polyamide of desired molecular weight and then cooling the product in an oxygen-free environment.
5 more elements
A free flowing, polyamide product wherein Bishexamethylene triamine present in the product is less than 0.22 mg/g, produced by a process comprising the steps of:
- a) polymerizing initial materials comprising an oxygen free equimolar salt of a dicarboxylic acid and hexamethylene diamine, under conditions such that the reacting materials never completely liquify, at reaction temperatures below the melting transition temperatures of the initial materials, any intermediate condensation products and any end products,
- 1) in an oxygen-free environment,
- 2) at essentially atmospheric pressure,
- 3) supplying amine, amines, or carboxylic acids, in an amount sufficient to balance acid and amine ends,
- 4) under an inert gas atmosphere,
- 5) while agitating, to produce a freely flowing solid prepolyamide;
- and
- b) further polymerizing the solid prepolyamide of step a) to a polyamide of desired molecular weight and then cooling the product in an oxygen-free environment.
5 more elements
Dependencies are inferred from the claim text.