| 摘要 |
Metal articles, in particular metal pipes, metal containers and large metal parts, preferably large pipes, are coated with cured epoxy resin compositions, the coating comprising a cured coating containing A) a solid epoxy resin based on 4,4'-diphenylolpropane and/or 4,4'-diphenylolmethane and epichlorohydrin, B) a curing catalyst and C) thixotropic agents, where the curing catalyst B) contains at least one compound B1) of the formula (I) or (II) <IMAGE> in which R is hydrogen, or B2) an adduct of the compounds B1) or substituted compounds of these formulae in which R is as defined in Claim 1 with low-molecular-weight epoxy resins having an epoxide equivalent weight of from 50 to 2000, or B3) a mixture of component B1) or B2) with the abovementioned substituted compounds of the formulae (I) and (II). The metal articles are coated with a pulverulent paint based on highly reactive curable epoxy resins which gives, in particular, toxicologically acceptable, heat- and chemicals-resistant, electroinsulating coatings. During this operation, the articles are heated to a temperature above the melting point of the resins, but sufficient for curing the epoxy resins, the resins are applied to the hot surface, which has already been cleaned before the heating, in the form of pulverulent paints by the electrostatic spray process or the whirl sintering (fluidised-bed sintering) process, melted to form a uniform film and cured directly without a further operation. During the application and curing process of the film, cracking phenomena of the organic components of the paint are not observed, in spite of the high temperature of the substrate, so that neither discolouration of the coating nor impairment of the properties occurs. The coatings are distinguished by the absence of pores and the high impact strength and by resistance to water and aggressive liquids. |
