Lupraphen 8101 Difunctional, aliphatic, polyester polyol. BASF-Elastogran Polyurethane (PU) - Polyols >> Polyester Lupraphen 8101 is a difunctional, aliphatic, polyester polyol. Lupraphen 8101 is used to improve the fire retardancy of rigid foams, especially of PIR formulations. Difunctional, aliphatic, polyester polyol. Contains BHT. Improves fire retardancy.