| 摘要 |
1,155,408. Coated metal surfaces. MINNESOTA MINING & MFG. CO. 8 Aug., 1966 [9 Aug., 1965], No. 35477/66. Heading B2K. [Also in Division C3] Metal surfaces, especially steel pipes, are coated with a particulate composition which is initially thermoplastic but rapidly thermosets when applied to a heated surface e.g. at 150‹C. The composition comprises: (A) an epoxy resin which is solid at room temperature; (B) an aromatic polyamine which is solid at room temperature and which contains at least two nucleus primary or secondary amine groups and a total of at least three active hydrogen atoms, e.g. 4, 4'-methylene dianiline or a phenylene diamine; and (C) as catalyst a mixture of (i) a Sn, Zn, Fe, Co, Mn or Pb salt of a carboxylic acid and (ii) a carboxylic acid or anhydride. The amine (B) is present in proportions so as to provide 0.85-1.5 active hydrogen equivalents per epoxide equivalent of (A) and the quantity of carboxylic acid present in (C) is not greater than 0.2 equivalents of acid per epoxide equivalent of (A). The metal salt in (C) may be present at between 0.2. and 5% by weight of the epoxy resin. A well bonded, flexible, tough, heat and chemical resistant coating is obtained by applying the composition to a surface at > 150‹C and maintaining the temperature at this level for a time sufficient to fuse, gel and cure the particles. |
