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:
Oct. 22, 1996
Filed:
Feb. 21, 1995
Wolfgang Br auer, Leverkusen, DE;
Friedemann M uller, Neuss, DE;
Herbert Heidingsfeld, Frechen, DE;
Bernhard Schulte, Krefeld, DE;
J urgen Winkler, Langenfeld, DE;
Bayer Aktiengesellschaft, Leverkusen, DE;
Abstract
A method whereby the properties, particularly the recrystallisation temperature, of thermoplastic polyurethane elastomers, particularly those suitable for processing by extrusion, are kept constant during continuous manufacture in screw-type extruding machines by continuously adding substantially straight-chain hydroxyl-terminated polyols having a molecular weight of 500 to 5000, organic diisoicyanates and diol and optionally triol chain-lengthening agents having a molecular weight of 62 to 500, the molar ratio of polyols to chain-lengthening agents being 1:1 to 1:5, and by continuous addition of a catalyst, wherein the recrystallisation temperature is set at a value at least 2.degree. C. below the value for the corresponding TPU manufactured without a catalyst, and when the set recrystallisation temperature is exceeded, the amount of continuously supplied catalyst is increased, whereas when the value falls below, the amount is decreased so as to maintain the set value, the resulting elastomers and use thereof for extrusion.