3M(TM) Scotch-Seal(TM) Polyurethane Sealant 540 Gray, 55 gal (50) Open Head Lined Drum, 1 per case 3M(TM) Scotch-Seal(TM) Polyurethane Sealants are one component, moisture curing products which form permanently elastic bonds. Bonds to a wide variety of materials including plastics, FRP, SMC, aluminum, steel, coated metal, and wood.