CFC-Free Polyether Polyurethane Systems for Footwear Applications

The removal of CFCs from polyurethane systems for footwear applications is an environmental necessity. However this has proven technically difficult for polyether based systems. Although polyether systems have a much superior hydrolytic stability than polyesters, the physical properties are inherently lower. In the past this problem was resolved by using CDCs as blowing agents. Such materials blow very efficiently in the interior of the mould material but much less efficiently in the regions adjacent to the cool mould wall. Hence, high density boundaries-or integral skins- are thus formed