Polyurethane rubber for peroxide crosslinking for the manufacture of rubber goods with good tear and abrasion resistance and excellent resistance to swelling and ozone. Vulcanizates made from Urepan 641 G are characterized by excellent resistance to hydrolysis compared with other polyester rubbers. Polyaddition product made from diphenyl-methane diisocyanate and polyester; small quantities of a polymeric carbodiimide.