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:
Dec. 09, 2014
Filed:
Aug. 28, 2009
Brigitta Otto, Milow, DE;
Rainer Linke, Butzbach/Bodenrod, DE;
Oliver Schmidt, Langenselbold, DE;
Lurgi Zimmer GmbH, Frankfurt am Main, DE;
Abstract
A method is disclosed for producing polymers with a neutral color tone, wherein a blue and red dye are added before entry into the last polyreaction stage, wherein adjustment of a neutral color tone of the polymer, using a total dye concentration in the polymer of no more than 3 ppm and a proportion of the blue dye in the resulting dye mixture of at least 50% by weight, occurs through independent adjustment of a and b color values in the Lab color space by determination of a and b color values of the polymer without addition of dyes, establishment of the total dye concentration depending on the b-value shift to be achieved, establishment of the required mixture ratio of the colors red and blue depending on the a-value shift to be achieved, and metering of the established content of dye mixture into the reaction mixture.