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. 06, 1979
Filed:
Apr. 10, 1978
Louis M Alberino, Cheshire, CT (US);
Curtis P Smith, Cheshire, CT (US);
The Upjohn Company, Kalamazoo, MI (US);
Abstract
A process is described for converting organic polyisocyanates to carbodiimide-containing polyisocyanates by heating said organic polyisocyanates in the presence of an organoarsine-substituted polystyrene carbodiimide-forming catalyst until a desired level of conversion is achieved, followed by separation of catalyst from product. It is thus possible to obtain a carbodiimide-containing polyisocyanate which is free from catalyst and hence free from the possibility that carbodiimide formation can continue on storage of the product. In a particular embodiment the process is employed to convert methylenebis(phenyl isocyanate), which is normally solid at ambient temperatures, to a storage stable liquid product. The polymeric catalysts employed in the process are characterized by a recurring unit of the formula: ##STR1## wherein R.sub.1 and R.sub.2 are hydrocarbyl, R.sub.3 is hydrogen, chloro or methyl, R.sub.4 is hydrogen or methyl and n is 0 or 1.