METHOD FOR ANTICORROSIVE INSULATION OF WELDING JOINTS AND DAMAGED LOCATIONS OF PIPELINE

• Main Authors: DEBERDEEV R.JA, STOJANOV O.V, MUKHAMEDZJANOVA EH.R, KHUZAKHANOV R.M, NIKITINA N.N, ZAIKIN A.E, KAPITSKAJA JA.V
• Format: Patent
• Language: English; Russian
• Published: 20.05.2004
• Edition: 7
• Subjects: ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; ADHESIVES; BLASTING; CHEMICAL PAINT OR INK REMOVERS; CHEMISTRY; COATING COMPOSITIONS, e.g. PAINTS, VARNISHES ORLACQUERS; CORRECTING FLUIDS; DYES; ENGINEERING ELEMENTS AND UNITS; FILLING PASTES; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVEFUNCTIONING OF MACHINES OR INSTALLATIONS; HEATING; INKS; JOINTS OR FITTINGS FOR PIPES; LIGHTING; MEANS FOR THERMAL INSULATION IN GENERAL; MECHANICAL ENGINEERING; METALLURGY; MISCELLANEOUS APPLICATIONS OF MATERIALS; MISCELLANEOUS COMPOSITIONS; NATURAL RESINS; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; PAINTS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; PIPES; POLISHES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; THERMAL INSULATION IN GENERAL; USE OF MATERIALS AS ADHESIVES; USE OF MATERIALS THEREFOR; WEAPONS; WOODSTAINS

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