| 摘要 |
<p>A method of coating metallic pipe is disclosed. The method comprises heating the pipe to a temperature of at least 200 °C and applying an epoxy resin composition having a thickness of at least 300 microns to the outer surface of the heated pipe. Before the epoxy resin composition has completely cured, but preferably after it has gelled, a coating of a modified polyolefin is applied in a thickness of up to 500 microns. The modified polyolefin is a homopolymer or copolymer of hydrocarbon alpha-olefins having 2-10 carbon atoms that has been modified by grafting with ethylenically unsaturated organic carboxylic acid or anhydride. An outer coating of a polyolefin is then applied in a thickness of at least 300 microns, the polyolefin being a homopolymer or copolymer of hydrocarbon alpha-olefins having 2-10 carbon atoms and preferably a homopolymer of ethylene or propylene, or a copolymer of ethylene and a C3-C10 hydrocarbon alpha-olefin. The resultant coating is resistant to impact damage and cathodic disbondment. The coated pipe may be used in buried pipelines in the petroleum industry.</p> |
