MOLDED AND PLATE POLYURETHANE FOAM PREPARED FROM POLYOLES AND POLYOXIALKYLENE CATALYZED BY A COMPLEX OF DOUBLE METALLIC CYANURES AND POLYOLS APPROPRIATE FOR PREPARATION.

摘要

A DMC-catalyzed multiblock polyol comprising oxypropylene units, comprising: i) an internal block comprising oxypropylene units and comonomer units copolymerized therewith, said internal block being preparable by oxyalkylation of one or more initiators in the presence of a catalyst of DMC or a non-DMC catalyst, with a first oxyalkylation mixture comprising propylene oxide and as a stabilization modifying comonomer at least one comonomer selected from the group consisting of ethylene oxide, substituted or unsubstituted C4-C20 olefin oxides, oxetane , methyloxetane and caprolactone, and ii) at least one external block comprising oxypropylene units and comonomer units copolymerized therewith, said external block being prepared by oxyalkylation in the presence of a DMC catalyst i), with a second oxyalkylation mixture comprising propylene oxide and as a comonomer modifies For stabilization at least one comonomer selected from the group consisting of ethylene oxide, substituted or unsubstituted C4-C20 olefin oxides, oxetane, methyl oxethane and caprolactone such that: the concentration and / or nature of at least one comonomer in the second mixture differ from those of the first mixture; Are at least 95% by weight of the polymerized oxypropylene units randomly copolymerized in the comonomer units in the internal and external blocks; Is the content of copolymerized comonomer in the outer block less than in the inner block; and with the proviso that when only oxyethylene moieties are present as comonomers, they are present in an amount greater than about 1.5% by weight with respect to the total amount of ethylene oxide and propylene contained therein.