Chemical recovery of polyurethane scrap - by reaction with amine(s) in presence of catalysts

摘要

In a process for recovering polyurethane scrap by chemical means, in which the scrap is reacted with a material capable of transamination reaction, the improvement comprises effecting the reaction at less than 130 deg.C (pref. less than 100 deg.C) by contacting the PU to be recovered with prim. and/or sec. amine(s) having not more than 12C in the chain, in basic medium and in presence of a catalyst comprising the following cpds. or their compatible mixts.:- (a) ZnCl2, SnCl2; (b) AlCl3, Zn(NO3)2, ZnBr2, AgNO3, (c) bisublimated iodine, ZnSO4, FeCl2, AlBr3, orthoboric acid, CaCl2, NaOAc, NaI, (d) N,N-dicyclohexyl- carbodiimide, Ag oxide, 2,4-dinitrophenyl hydrazine, KI, Na metabisulphite, MgSO4, Ca resinate, BaCl2, boric acid, ZnI2, La chloride and Rh chloride. Used for recovering PU scrap from PU foam production or mouldings. The process allows a saving in energy, being effected at moderate temps., and also direct prodn. of materials which can be used as raw materials for a fresh prodn. of PU.