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:
Apr. 27, 1999
Filed:
Jan. 22, 1998
George M St George, Lake Jackson, TX (US);
Stephen B Willis, Lake Jackson, TX (US);
David A Wilson, Richwood, TX (US);
The Dow Chemical Company, Midland, MI (US);
Abstract
A process for preparing a ferric chelate of an aminopolycarboxylic acid wherein an iron-containing material is reacted with an aminopolycarboxylic acid chelant in the presence of a base, which comprises employing reactants such that the molar ratio of chelant to iron is from about 0.8 to about 0.99, is disclosed. In preferred embodiments the chelate is a ferric ammonium ethylenediaminetetraacetic acid chelate. The inventive chelates show a reduced tendency to form a dark precipitate upon standing. This process is particularly suitable for use in preparing chelates for use in applications such as photographic bleaching. The corresponding ferric chelate composition and products prepared by the described process are also disclosed.