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. 30, 1987
Filed:
Oct. 29, 1985
Hanns P Muller, Odenthal, DE;
Werner Clarenz, Bergisch Gladbach, DE;
Heinrich Grave, Bergisch Gladbach, DE;
Bayer Aktiengesellschaft, Leverkusen, DE;
Abstract
The present invention relates to a process for the production of aliphatic and/or cycloaliphatic diisocyanates which are color stable to heat, which is characterized in that a diisocyanate with aliphatically-and/or cycloaliphatically-bound isocyanate groups is heated in the presence of about 0.1 to 3% by weight, based on the diisocyanate, of at least one compound which is soluble in the diisocyanate and contains at least 3% by weight of structural units corresponding to the formula: ##STR1## for up to about 5 hours at a temperature of about 100.degree. to 220.degree. C. and the diisocyanate which has been treated in this way is subsequently purified by distillation. The present invention also relates to the use of the products of the present process for the production of modified polyisocyanates having improved coloration.