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:
Jun. 28, 1983
Filed:
Jun. 30, 1981
Dietrich Lach, Friedelsheim, DE;
BASF Aktiengesellschaft, Ludwigshafen, DE;
Abstract
Mineral tanned leather is frequently retanned with synthetic tanning agents to improve the fullness and softness, but leather retanned by the prior art methods is difficult to dye in full shades with anionic dyes. According to the invention, condensation products of C.sub.1-4 aldehydes with certain aromatic sulfonic acids or carboxylic acids containing amino groups are employed for retanning, thereby improving the receptivity of the leather for anionic dyes. These acids have the general formula ##STR1## where X and X' are independently H, --CH.sub.2 --SO.sub.3 H or --CH.sub.2 --OH, A is a benzene radical, Y and Z are independently H, --SO.sub.3 H or --CO.sub.2 H, R is H or C.sub.1-4 -alkyl and n is from 0 to 10, with the proviso that at least one sulfonic acid or carboxyl group is present in the molecule.