EPOXY/POLYOLEFIN COATING PROCESS

摘要

A method of coating metallic pipe is disclosed. The method comprises heating the pipe to a temperature of at least 200 DEG 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 at least 300 microns. The modified polyolefin is a homopolymer of copolymer of hydrocarbon alpha-olefins having 2-10 carbon atoms that has been modified by grafting with ethylenically unsaturated organic carboxylic acid or anhydride. The resultant coating is resistant to impact damage and cathodic disbondment. The coated pipe may be used in buried pipelines in the petroleum industry.