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:
Jul. 16, 1991
Filed:
Sep. 21, 1990
Beatrix Frauendorf, Leverkusen, DE;
Michael Kausch, Cologne, DE;
Rolf-Volker Meyer, Krefeld-Bockum, DE;
Bayer Aktiengesellschaft, Leverkusen-Bayerwerk, DE;
Abstract
The invention relates to a process for the production of highly concentrated and, surprisingly, viscosity-stable solutions of segmented polyurethane urea elastomers in highly polar solvents, such as dimethyl formamide and dimethyl acetamide, having little or no tendency to turn to paste, characterized by the use of certain primary and secondary cycloaliphatic monoamines or cycloaliphatic monisocyanates as chain-extending agents/blocking agents in the reaction of NCO prepolymers based on relatively high molecular weight dihydroxy compounds and (preferably aromatic) diisocyanates with aliphatic and and/or cycloaliphatic diamine chain-extending agents. The chain terminators according to the invention also show unexpected iprovements in the color of the elastomer solution and also in the stability of the end products, preferably filaments, to light and noxious gases. The invention also relates to elastomers of corresponding composition containing special terminators, preferably in the form of filaments, films or coatings showing improved stability to light and waste gases.