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:
Mar. 11, 1997
Filed:
Feb. 09, 1996
Bayer Aktiengesellschaft, Leverkusen, DE;
Abstract
The present invention relates to polyisocyanate mixtures which are reaction products of 4,4'-diphenylmethane diisocyanate as the isocyanate component, are liquid at greater than 5.degree. C. and have an NCO content of 14.5 to 24% by weight and an allophanate group content (calculated as C.sub.2 HN.sub.2 O.sub.3, molecular weight = 101) of 7.7 to 14.5% by weight; a process for the production of these polyisocyanate mixtures by reacting 4,4'-diphenylmethane diisocyanate as the exclusive isocyanate component with one or more monohydric alcohols having 4 to 16 carbon atoms at an NCO/OH equivalent ratio of 5:1 to 8.5:1 and at a temperature of up to 160.degree. C. to form urethane groups and during or subsequent to urethane formation, converting the urethane groups to allophanate groups in the presence of a catalyst which promotes allophanate formation; and the use of these polyisocyanate mixtures as the polyisocyanate component in two-component polyurethane coating compositions.