One-Shot Semi-Rigid Foam System- Process and Properties

Abstract

The word "one-shot" in flexible urethane foam technology was the harbinger of lower cost products with reproducible properties. The development of L-520 organosilicone stabilizers along with tin catalysts made one- shot flexible foam a reality. The basic prin ciples learned in flexible foam have been ex tended to a one-shot semi-rigid foam system described in this article. In particular, a sys tem. to provide stabilization during the foam rise and cell opening at the end of the rise was required. To the usual benefits of a one- shot system we added versatility in formu lating. Foam properties are controlled by a proper choice of polyols, water and the tin and amine catalysts. This control and versa tility is necessary to meet the property de mands of free-blown and molded foam prod ucts. This new system was developed on the bench and proven on production machines.