The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 16, 1978
Filed:
Sep. 20, 1976
Karl W Rausch, Jr, Hamden, CT (US);
The Upjohn Company, Kalamazoo, MI (US);
Abstract
A process is described for the conversion of solid polymers to powders in which the particles are substantially spherical and uniform in size. The polymer is dissolved in an aprotic solvent which is at least partially miscible with water but immiscible with mineral oil, the resulting solution is emulsified in mineral oil, and a minor amount of water or a glycol is added with agitation. The powdered polymer separates and is isolated by filtration, centrifugation and the like. Alternatively, when the precipitant is a glycol having a boiling point higher than the aprotic solvent in which the polymer is initially dissolved, the powdered polymer is isolated by filtration, centrifugation and the like after first removing the aprotic solvent and glycol by distillation. The process is applicable to a wide variety of polymers (polyimide, polyamides, polyamideimides, polyurethanes) which are soluble in aprotic solvents.