METHOD OF APPLYING COATING TO PROTECT AND RENDER ANTICORROSION PROPERTIES TO IRON OBJECTS AND STEEL PIPES, AND METHOD OF MANUFACTURING A COATED STEEL PIPE Russian patent published in 1997 - IPC

FIELD: protective coatings. SUBSTANCE: surface of steel pipe is covered with epoxycyanate primer composition wherein polyisocyanate and epoxypolyol amounts are such that NCO/OH ratio is 0.6-0.9. Then a polyurethane composition is sprayed by the aid of a sputter gun, said composition containing polyurethane prepolymer and a component with active hydrogen atom including a compound with active hydrogen atom and aromatic polyamine (chain extension) with equivalent ratio NH₂/OH ranged from 60/40 to 100/0. Composition for outer coating is continuously sprayed onto primer layer while the pipe is axially rotated and displaced either itself or sputting gun is displaced. EFFECT: improved procedure. 2 cl, 20 tbl