| 摘要 |
PROBLEM TO BE SOLVED: To eliminate the generation of smoke substantially upon combustion since halogen based fire retardant is not added and provide fire retardancy as the interior material for a building by a method wherein a metallic thin sheet is laminated on both sides of a polypropylene sheet having a specified melt fluidity index as well as expansion ratio. SOLUTION: Metallic thin sheets are laminated on both sides of a polypropylene sheet, having melting and flowing index [MFR (230 deg.C; 2.16kg f] is 0.3g/10min or less and an expansion ratio of 1.5-5.0, to form a composite board. In this case, the polypropylene sheet is produced preferably from polypropylene having a heat distortion temperature of 90 deg.C or more while the thickness of the metallic sheet is preferably 100-500μm. The composite board, thus obtained, is useful for interior parts building materials and prominent in fire retardant property since black smoke and poisonous gas will not be generated substantially even when the composite board is brought into contact with flame or high temperature at the time of fire and the like. In this case, the actual examples of the metallic thin sheet are aluminum sheet, iron sheet, steel sheet and the like. |
