Fina Research, S.a.

Michel Gillard

Ludwig Karl Rijkse

Willem Sietses

Edwin Verwey

Pigmented powder coating products based on low melting point fluorine-based terpolymers, preferably on those made from a majority of vinylidene fluoride copolymerized with tetrafluoroethylene and hexafluoropropene, are capable of providing coatings with controllable gloss properties. The process for preparing coatings from the powders is essentially characterized by the selection of the temperature at which the desired gloss can be obtained, from low to high, without degradation of the mechanical properties.

Fluorinated powder coatings having improved gloss

Powder compositions comprising about 5-15 wt % of PVdF-compatible thermoplastic resin, about 50-90 wt % of a thermosetting binder system, about 0-35 wt % of pigments and about 0-3 wt % of leveling agent are disclosed which are particularly suitable for use as primers with a later application of a pigmented PVdF-based top coating. Preferred compositions are based on an epoxy system containing about 8 wt % of PVdF or acrylic thermoplastic resin, 5-25 wt % of pigments and 0.7-1 wt % of leveling agent.

Preparing powder primer of thermoset binder and PVdF-compatible

Powder primer of thermosetting binder and PVdF-compatible thermoplastic

Vinylidene fluoride copolymers having a melting temperature below about 160.degree. C. are used to prepare pigmented powder coatings for galvanized steel. The coatings are corrosion-resistant and generally show a high gloss.

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Corroy-le-Chateau, Belgium

Michel Gillard