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US 5,665,854 AGranted
Low temperature nylon polymerization process
AssigneeE. I. Du Pont de Nemours and Company
InventorsLeonard Edward Raymond Kosinski, Richard Robert 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.
Claims19
A process for the preparation of polyamides which process comprises the steps of:
- a) polymerizing under conditions such that the reacting mass never completely liquefies, at reaction temperatures below the melting transition temperatures of the initial materials, the intermediate condensation products and the end products, an oxygen free aminocarboxylic acid,
- 1) in an oxygen-free environment,
- 2) at essentially atmospheric pressure,
- 3) while supplying amine, amines, diamines or carboxylic acid(s), in an amount sufficient to achieve the desired balance of acid and amine ends,
- 4) under an inert gas atmosphere, either purged or unpurged,
- 5) while providing a degree of agitation to maintain the necessary level of motion in the mass to produce a freely flowing product;
- 6) in the substantial absence of a solvent, suspending agent or diluent;
- and
- b) further polymerizing the prepolyamide product of step (a) in the solid phase to a polyamide of desired molecular weight and then cooling the product in an oxygen-free environment.
6 more elements
A process for the preparation of copolyamides which process comprises the steps of:
- a) polymerizing under conditions such that the reacting mass never completely liquefies, at reaction temperatures below the melting transition temperatures of the initial materials, the intermediate condensation products and the end products, wherein the starting materials are selected from (i) an oxygen free equimolar diammonium dicarboxylate salt composed of one or more diamines and one or more dicarboxylic acids, provided that the salt is composed of more than one of at least one of the diamine and the dicarboxylic acid, (ii) physical mixtures of one or more equimolar diammonium dicarboxylate salts (homopolymer or copolymer precursor salts) with one or more amino carboxylic acids;
- (iii) physical and or chemical mixtures of one or more than one amino carboxylic acid;
- and (iv) chemical salts comprising one or more equimolar diammonium dicarboxylate salts (homopolymer or copolymer precursor salts) and one or more amino carboxylic acids,
- 1) in an oxygen-free environment,
- 2) at essentially atmospheric pressure,
- 3) while supplying amine, amines, diamines or carboxylic acid(s), in an amount sufficient to achieve the desired balance of acid and amine ends,
- 4) under an inert gas atmosphere, either purged or unpurged,
- 5) while providing a degree of agitation to maintain the necessary level of motion in the mass to produce a freely flowing product;
- 6) in the substantial absence of a solvent, suspending agent or diluent;
- and
- b) further polymerizing the prepolyamide product of step (a) in the solid phase to a polyamide of desired molecular weight and then cooling the product in an oxygen-free environment.
8 more elements
Dependencies are inferred from the claim text.