Methods of Minimising Density Gradients in Rigid Polyurethane Foams

This paper discusses methods to minimise density gradients in moulded rigid polyurethane foams of densities 0.35 g/cc and 0.80 g/cc. Methods examined were changing the nature and concentration of the amine catalyst, the use of high functionality isocyanates and varying the mould temperature. All methods can reduce the density gradient in moulded foam compared to a control formulation.