Verfahren zur Herstellung haftfester und heißwasserbeständiger Polyolefin-Überzüge auf metallischen Gegenständen

1,219,398. Polyolefin coatings . on metals. METALLGESELLSCHAFT A.G. 24 Oct., 1969 [8 Feb., 1969], No. 52317/69. Heading B2E. Adherent, hot water resistant olefin polymer or copolymer coatings are provided on metal objects by applying a mixture of a plasticised phenolic resin and colloidal silicic acid as a first coating, applying a. powder of an olefin polymer or copolymer over said first coating and fusing the powder. Resol type resins based on phenol or cresol, particularly wherein the methylol groups have been etherified with primary alcohols (e.g. butanol), are suitable and these may be plasticised with soft resins, fatty oils and/or alkyd resins and dissolved in organic solvents. Colloidal silicic acid of SiO 2 content greater than 90% and particle size 5-50Á may be added to provide a resin: coloid ratio of 2:1-6:1. The mixture may be applied by dipping or spraying; The object may be heated to 200-450‹C after the first coating has dried and the powdered polyolefin (e.g. polyethylene, polypropylene, ethylene/vinyl acetate copolymer) may then be applied by dipping in a fluidised bed, rolling in a stationary powder bath, spraying, pouring or by electrostatic methods. Specified substrates are steel tubes and sheets of steel, aluminium and brass.