To provide a rotational molding method of a hollow product of a polyurethane resin which has a uniform thickness and also a high dimensional accuracy and which is made free from a tear or the like on the occasion of releasing the product from a mold and has a high quality.
A compound solution is prepared by adding an amine catalyst facilitating polymerization and a metal catalyst or a temperature-sensing catalyst improving demoldability to a two-part reaction type polyurethane which consists of a polyol constituent and an isocyanate constituent and of which the viscosity is regulated to be 2,000 cps or below (25°C). Rotation is conducted before heating, with this solution charged in a mold before heating, and then rotational molding is conducted with a mold temperature raised to and kept at a temperature of 100°C or below .
SUZUKI TATSUYA
SAKAMOTO MEGUMI
BASF INOAC POLYURETHANES LTD
Akio Najima
Fumio Yamamoto