Polyurethane Microcellular Elastomers. 4. High Air Permeable Moulded Systems

The influence of an ester type macrodiol (PEBA) on the air permeability, on the foam formation kinetics as well as on the compression behaviour has been studied, in the case of RIM materials. Due to its antisurfactant effect, the presence of an ester type macrodiol in the ether type RIM materials leads to an open cell structure. PEBA has a reducing effect on the compression resistance, while it increases the hysteresis loss of the material. The increased quantity of water encourages the formation of a closed cell structure as well as improving the compression resistance. Both the water and PEBA have an improved effect on the foaming mass reactivity.