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. 27, 1999
Filed:
Jan. 08, 1998
Elmar Wolf, Recklinghausen, DE;
Huels Aktiengesellschaft, Marl, DE;
Abstract
A process for the preparation of an isocyanurate-free uretdione of isophorphone diisocyanate, comprising dimerizing an isophorone diisocyanate of the general formula: ##STR1## in an inert organic solvent or in the absence of a solvent, with the aid of a catalysts, at a temperature of 0 to 80.degree. C.; isolating the uretdione formed from the reaction mixture after a conversion of 5-70%, without prior deactivation of the catalyst, by thin film distillation at 100-180.degree. C. under 0.01-0.5 mbar; wherein the isophorone diisocyanate has a purity of .gtoreq.99.9% by weight, and the concentration of the unknown first runnings component in a gas chromatogram of the isophorone diisocyanate employed for the dimerization is not greater than 0.05 area%; and wherein R.sup.1 and R.sup.2 are identical or different alkyl radicals having 1-8 C atoms, or with the N atom bonded to the ring, can form a common 5- or 6-membered ring which can contain a CH--CH.sub.3 group, an N--CH.sub.3 group or an O atom instead of a CH.sub.2 group.