Inventors:
John W. McLaren - Waterford MI
Kenneth J. Rettmann - Novi MI
Assignee:
The Dow Chemical Company - Midland MI
International Classification:
C08J 328
US Classification:
522162, 522166, 522 83, 525403, 525452, 525453, 525458, 525528, 528 59, 528 61, 528 65, 528 68, 528481, 528503, 264478, 264492
Abstract:
A method of treating reaction injection molded polyurethane, polyurethane/urea and polyurea polymers comprising exposing a reaction injection molded polyurethane, polyurethane/urea or polyurea polymer to an amount of infrared energy sufficient to increase the temperature of the polymer to at least 175Â C. , and then maintaining the temperature of the polymer at or above that temperature, for a time sufficient to increase the Gardner impact property, as measured using ASTMD-3029, when compared to the same polymer which has been heated to the same temperature and maintained thereat for the same time in a convection oven. The invention produces marked improvements in impact, heat sag and heat distortion temperature properties, and thus is particularly suited to rapid preparation of parts using a mass production conveyor and is particularly well-suited to preparation of parts which are to be subjected to later high temperature processes, such as the âE-coatâ process.