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. 18, 1992
Filed:
Jul. 17, 1991
Thomas Staffel, Hurth, DE;
Renate Adrian, Hurth, DE;
Hoechst Aktiengesellschaft, Frankfurt am Main, DE;
Abstract
To prepare essentially water-insoluble, chain-form ammonium polyphosphate from equimolar amounts of di- ammonium phosphate and phosphorus pentoxide in the presence of ammonia at temperatures of from 170.degree. to 350.degree. C. with constant mixing, kneading and comminution, at least some of the diammonium phosphate and phosphorus pentoxide is replaced by partially ammoniated polyphosphoric acid. A plant for carrying out this process can comprise a sealed reactor (1) which is provided with metering devices (2, 3) and feed tubes (4, 5) for phosphorus pentoxide and diammonium orthophosphate, an ammonia feed tube (8), an ammonium polyphosphate discharge tube (9) and a line for offgas. Rotatable mixing, kneading and comminution elements are provided inside the reactor (1). Furthermore, a heatable stirred tank (11) which can be charged with polyphosphoric acid via a feed line (13) is provided and can be used to remore water vapor and ammonia from the offgas flowing from the reactor (1) via the line (20) and from which partially ammoniated polyphosphoric acid can be introduced into the reactor (1) via an outlet line (17).