Method for extracting granular polyamides and for preparing polyamide powders
AssigneeChemische Werke Huls Aktiengesellschaft
InventorsSrinivasan Sridhar, Horst Hedden
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Abstract
A method for extracting granular polyamides having at least 10 aliphatically bound carbon atoms per carbonamide group and a method for preparing polyamide powders from the extracted granular polyamides. The granular polyamides are extracted with dimethyl formamide at temperatures between about 70.degree. and 100.degree. C. The extracted granular polyamides are then dissolved in dimethyl formamide and the polyamide powders are formed by cooling the solution.
Claims7
A method for preparing powdered polycarbonamide having at least 10 aliphatically bound carbon atoms per carbonamide group or mixed polycarbonamide containing at least 70 percent by weight of said polycarbonamide as constituents consisting of essentially:
- a. extracting said polycarbonamide in granular form with dimethyl formamide at a temperature of about 70.degree. to 100.degree. C., to remove the monomerous and low molecular ingredients;
- b. separating the extracted polycarbonamide in granular form from the dimethyl formamide residue;
- c. dissolving the separated and extracted polycarbonamide in dimethyl formamide at a temperature between about 140.degree. and 150.degree. C. to form a solution;
- and
- d. precipitating said powdered polycarbonamide by cooling said solution.
Dependencies are inferred from the claim text.