The invention discloses composite slowly-recoverable soft
polyurethane foam and a preparation method thereof. The composite slowly-recoverable soft
polyurethane foam is prepared from a component A and a component B;
isocyanate is adopted as the component A; the component B is prepared from 40%-70% of b1, 20%-40% of b2, 0-30% of b3, 0.1%-20% of b4, a
foaming agent accounting for 1%-5% of the total amount of a polyether component, a foam stabilizer accounting for 0.2%-3% of the total amount of the polyether component and a catalyst accounting for 0.2%-5% of the total amount of the polyether component, wherein the polyether component is prepared from b1, b2, b3 and b4, and b1+b2+b3+b4=100; PO-EO copolymerized polyether
polyol or
polypropylene oxide of which the
mass content of epoxypropane is more than 90% and the functionality degree is 3 when the amount is within 200-350 is adopted as b1; PO-EO copolymerized polyalcohol of which the
mass content of epoxypropane is more than 50% and the functionality degree is 3 when the amount is more than 1000 is adopted as b2; PO-EO copolymerized polyalcohol of which the
mass content of PO is more than 80%, the functionality degree is 3 and the primary hydroxyl content is more than 70% when the amount is more than 1000 is adopted as b3; PO-EO copolymerized monohydric
alcohol of which the
mass content of EO is more than 75% when the amount is more than 1000 is adopted as b4. The composite slowly-recoverable soft
polyurethane foam has the dual characteristics of structural-type slow
recovery and air bag-type slow
recovery, and the slow
recovery of the foam is little in dependence on an
isocyanate index and the usage amount of slowly-recoverable polyether.