| 摘要 |
The present invention provides a coating for metallic pipes having improved corrosion and soil stress resistance, and adapted for both in-the-mill and over-the-ditch application to said pipes, which coating comprises:a first layer comprising a hot-melt rubberized adhesive applied to the outer surface of a pipe preheated to a temperature of 25.degree.-60.degree.C, said hot-melt rubberized adhesive comprising a physical blend or mixture of materials chosen from the group of asphaltenes, elastomers, rubbers, resins, polymers and copolymers, optionally including fillers, said hot-melt rubberized adhesive having the following physical properties: Ring and Ball softening temperature : 75.degree. 95.degree.C. Flow Properties, as defined by CSA Z 245.21 Spec: 112 mm. Viscosity at 175.degree.C : 10,000 - 100,000 cPs; and a second layer applied over the first layer, said second layer comprising a polyolefin material. Also described herein is a method for applying such coating to a metallic pipe surface. The pipe surface is first cleaned and the pipe is then preheated to a temperature of 25 - 60.degree.C; then hot-melt rubberized adhesive, heated to a temperature above its melting point, is applied to the preheated pipe as a first layer, and immediately thereafter a second layer comprising a polyolefin material, preferably in the form of a tape, is applied over the first layer. The pipeline coating of the present invention is especially suitable for pipeline rehabilitation.
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