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:
Aug. 04, 1992
Filed:
Feb. 19, 1991
Mo A Khuddus, Baton Rouge, LA (US);
David R Brackenridge, Baton Rouge, LA (US);
Ethyl Corporation, Richmond, VA (US);
Abstract
This invention relates to a process for preparing a white flame retardant product which principally contains a bisimide. The process comprises: providing an essentially water-free solution containing tetrabromophthalic anhydride and a solvent in a reaction vessel; forming a reaction mass by adding a diamine or a diamine salt to the solution at an addition rate such that, at the addition temperature, water formed during the addition is removed from the reaction mass substantially as it is formed; terminating the addition of the diamine when the molar ratio of the tetrabromophthalic anhydride initially present in the solution to the diamine or diamine salt added is at least about 2.00:1; maintaining the reaction mass at a temperature of at least 125.degree. C. for at least 0.5 hr after the addition; and recover from the reaction mass the flame retardant product.