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. 09, 1984
Filed:
Aug. 13, 1981
Chemische Werke Huls AG, Marl, DE;
Abstract
A process for producing a substantially isocyanurate-free uretidione dimer of isophorone diisocyanate, which is more than 98% decomposable by heat to isophorone diisocyanate, which comprises dimerizing isophorone diisocyanate, optionally in an inert organic solvent, in the presence of a catalyst of the formula X.sub.m P(NR.sub.2).sub.3-m wherein m=0, 1, 2; X=Cl OR of R wherein R is selected from the group consisting of the same or different aklyl radical, aralkyl radical, cycloalkyl radical, substituted cycloalkyl radical and radicals wherein two or more of the aforementioned radicals form a hererocyclic ring together with the nitrogen atom; at temperatures of 0.degree.-80.degree. C., isolating the resulting 1,3-diazacyclobutane-2,4-dione, after 5-70% conversion, without previous inactivation of the catalyst, from the reaction mixture as the residue of a thin film distillation and isolating the catalyst and monomer as the distillate.