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. 22, 2003
Filed:
Oct. 13, 2001
Renee Ellen Niziurski-Mann, Kingsport, TN (US);
Lucian Boldea, Jonesborough, TN (US);
Phillip Montgomery Hudnall, Kingsport, TN (US);
Michael Wayne Salyer, Kingsport, TN (US);
Eastman Chemical Company, Kingsport, TN (US);
Abstract
An improved method for making a p-phenylenediamine color developer concentrate in a free-base form wherein the sulfate or chloride salt of the color developer is contacted with an alkali metal hydroxide includes the steps of forming a liquid free-base layer and a water layer, separating the liquid free-base layer from the water layer; and mixing the liquid free-base with a water soluble hydroxy organic solvent, wherein the p-phenylenediamine color developer concentrate has at least 0.06 mol/l of a color developing agent in the free base form.