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:
Jan. 15, 1991
Filed:
Feb. 02, 1990
Horst Staendeke, Lohmar, DE;
Ursus Themmler, Erftstadt, DE;
Hoechst Aktiengesellschaft, Frankfurt am Main, DE;
Abstract
Phlegmatized, pulverulent red phosphorus with good free-flowing properties comprises 95 to 99.95% by weight of red phosphorus having a particle size of up to 2 mm, and 0.05 to 5% by weight of polyurethane as phlegmatization agent. This red phosphorus is prepared by introducing an aqueous polyurethane dispersion into an aqueous suspension of red phosphorus having a particle size of up to 2 mm, after a pH of from 5 to 9 has been set, in a manner such that 5 to 0.05 parts by weight of polyurethane are present per 95 to 99.95 parts by weight of red phosphorus, then stirring the mixture at a temperature of from 20 to 90.degree. C. for 0.5 to 3 hours, and finally drying the phlegmatized red phosphorus at elevated temperature after filtration.