METHOD FOR ANTICORROSIVE INSULATION OF WELDING JOINTS AND DAMAGED LOCATIONS OF PIPELINE Russian patent published in 2004 - IPC

FIELD: corrosion protection. SUBSTANCE: invention, in particular, relates to protecting underground pipelines against damages and soil and atmospheric corrosion. Method is accomplished by way of applying thermally shrinkable multilayer adhesive tape composed of (i) protective polyethylene tape layer electronically-and-chemically modified to absorb dose of 25-50 MRad and oriented in longitudinal direction by 25-75% and (ii) adhesive layer, which, before applying multilayer adhesive tape, is covered with epoxide composition and which adhesive layer is formulated with two ethylene/vinyl acetate copolymers differing from each other by 5-20% vinyl acetate group content and, additionally, a third ethylene/vinyl acetate copolymer with 27-30% vinyl acetate group content and showing melt flowability index 15-30 g/10 min, and further containing mineral filler and polyisocyanate as modifier. Adhesion of such coating to steel after exposure to salt water is increased by a factor of 1.7, while cathodic detachment is lowered by 2 times. EFFECT: enhanced anticorrosive protection and increased strength of adhesion to steel surfaces. 2 tbl