| 摘要 |
An article comprises a metal base, a bonding layer of maleic anhydride-modified polypropylene, and a top layer of a crystalline polyolefin. The base may be of aluminium, copper, steel, galvanized steel or tinplate, and may be a rigid sheet or a foil; it may be pre-treated by sand-blasting or phosphate or chromate treatment. Both plastics layers may be applied by coating processes such as airless spraying, flame spraying, electrostatic spraying or immersion in solutions or fluidized beds, followed by baking; alternatively, the top coat or both plastics coats may comprise pre-formed sheets which are laminated to the base by heat and pressure. The crystalline polyolefine may be polyethylene, polypropylene, a copolymer of ethylene and propylene, or a copolymer of either ethylene or propylene with another 1-olefine, such as 1-butene. The bonding layer may be the reaction product of maleic anhydride with polypropylene or a copolymer of propylene with ethylene or with ethylene plus other unsaturated hydrocarbons; in one example a maleic anhydride modified terpolymer of propylene, ethylene, and dicyclopentadiene is used.
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