INSULATION COATING FOR PROTECTION PIPES AGAINST UNDERGROUND CORROSION Russian patent published in 1997 - IPC

FIELD: paint and varnish industry, particularly anticorrosion protection of pipelines. SUBSTANCE: insulation coating for protection pipes against corrosion is manufactured of three layers. The first one which represents priming layer is manufactured on the base of bitumen and rubber. The second intermediate layer is manufactured of composition which comprises, %: butadiene methyl styrene rubber, 10.0-20.0; 4,4′, 4″-triphenylmethane triisocyanate, 0.04-0.2; sulfur, 0.2-0.7; organic solvent, the balance. The third layer being protective one is manufactured of extruded polyethylene. Pipe is preliminary heated before priming layer is applied on it. EFFECT: improved protection against corrosion. 3 cl, 2 tbl