METHOD OF INSULATING PIPES Russian patent published in 2000 - IPC

FIELD: polymer coatings. SUBSTANCE: rotating pipe is coated by reaction mixture containing aromatic polyisocyanate; organic compound with molecular weight 92 to 1000 having on average at least three hydrogen atoms reactive to isocyanates; aliphatic, cycloaliphatic, or aromatic polyamine with molecular weight 32 to 1000 as cross-linking agent; and foaming agent, serving for making at least one insulation layer of rigid foam plastic followed by applying overlaying thermoplastic layer. According to invention, reaction mixture contains, as additional cross-linking agent, compound with general formula I or II: (I) (II) where n is integer from 2 to 9, preferably 2 or 3, R¹ is hydrogen, C₁-C₉-alkyl, or radical with general formula wherein R² is hydrogen and R³ and R⁴ are hydrogen or methyl. EFFECT: improved insulation quality. 2 cl, 2 tbl, 4 ex