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. 12, 1977
Filed:
Nov. 21, 1975
Gregory A Campbell, Romeo, MI (US);
Howard W Cox, Birmingham, MI (US);
William C Meluch, Birmingham, MI (US);
General Motors Corporation, Detroit, MI (US);
Abstract
In accordance with a preferred embodiment of this invention, a controlled phase change is used to trigger an exothermic polymerization reaction in an injection molding process. The subject method comprises first, dispersing a crystalline urea reactant, 1,3-bis-(3-isocyanatotolyl) urea, in a liquid polyoxyalkylene polyol or mixtures thereof. Since the polyols do not dissolve the urea at room temperature, the dispersion is storage stable over an extended period of time. This is unexpected because the isocyanate and hydroxyl functionalities are normally quite reactive. In the barrel of the injection molding machine, the dispersion is heated to a temperature at which the polyol will begin to dissolve and thereby react with the crystalline urea to initiate a controllable polyurethane-forming reaction. At present, the specific urea disclosed above is preferred because of its ability to (1) form a storage stable dispersion, (2) dissolve in the polyol at a temperature below its decomposition temperature, and (3) react with the polyol at controllable rates once it has dissolved. All three properties are important to this invention and they enable the practitioner to use conventional injection molding equipment.