Abstract: A flame-retardant soundproofing material for vehicles includes a polyurethane foam obtained by foam-molding a urethane resin composition. The urethane resin composition includes an isocyanate component (A), a polyol component (B), a flame-retardant plasticizer (C), and an antioxidant (D). The isocyanate component (A) includes a mixture of 2,4?-diphenylmethane diisocyanate and 4,4?-diphenylmethane diisocyanate, and one or more modified products selected from a carbodiimide-modified product and a uretonimine-modified product of at least one of 2,4?-diphenylmethane diisocyanate and 4,4?-diphenylmethane diisocyanate of the mixture.

Abstract: A flame-retardant soundproof material for vehicles includes a polyurethane foam obtained by foam-molding a urethane resin composition. The urethane resin composition contains an isocyanate component (A), a polyol component (B), and an expandable graphite (C). The isocyanate component (A) includes a mixture of 2,4?-MDI and 4,4?-MDI, and one or more modified forms selected from carbodiimide modified forms and uretonimine modified forms of at least one of 2,4?-MDI and 4,4?-MDI. The content of the one or more modified forms in the urethane resin composition is 5.0 mass % to 8.8 mass %. The polyol component (B) includes a polyether polyol as a main constituent. The expandable graphite (C) has an expansion initiation temperature of 170° C. to 200° C., an expansion ratio of 10 or more at 250° C., and a content of 8 mass % to 20 mass % in the urethane resin composition.