Understanding the Fundamentals of Forced Cooling in the Production of Blowing Agent Free Flexible Slabstock Polyurethane Foams

Abstract

A rapidly developing method for blowing agent elimination in the production of flexible slabstock polyurethane foam is the use of forced cooling. This process overcomes many of the common problems related to discoloration and physical property loss in traditional low density water blown foams. Additional benefits of forced cooling include uniformity of certain physical properties throughout the foam bun and the elimination of storage space for bun curing. Understanding the relationship between the development and potential degradation of physical properties versus time in the production of blowing agent free flexible polyurethane foam is critical to the foam producers' successful implementation of these novel technologies. The prospect of quickly cooling internal bun temperatures to quench the reaction and reduce the resulting exotherm can be influenced by several important parameters. These parameters consist of: (a)novel polyol and modifier compositions for improved foam physical properties,(b) a thorough understanding of amine and tin catalysis, with the possibility of utilizing novel amine and tin catalysts, (c) understanding the time versus temperature relationship, and how this information can be used to ones advantage, and (d) understanding the equipment and process specific conditions involved in the cooling process and deciding what final physical properties are feasible and acceptable. Experiments and data pertaining to these important parameters will be presented and discussed with respect to the current scenarios confronting today's flexible slabstock polyurethane foam manufacturers.