Polyol recovery from elastomer polyurethane waste

Waste and scraps, from polyurethane elastomers, mainly from the shoe sole production, can be conveniently converted by a transesterification process into polyols which can be reused in the production of rigid foams, with both economical and ecological advantages. In the transesterification process, secondary reactions leading to amine formation, can be controlled by means of the reaction conditions. In the production of rigid foam the recovered products are mixed with fresh polyol; the recovered/fresh polyol ratio must be moderate in order to obtain materials with sufficiently high dimensional properties.