Modified polyester resin/organic peroxide systems for powder coatings which are applicable to temperature sensitive and metallic substrates

A modified polyester resin/organic peroxide system for powder coating which is applicable to temperature sensitive substrates and to metallic substrates comprising:

• a) a polyester resin which is a hydroxylated or carboxylataed polyester which possesses unsaturation in the chain and which originates from the reaction of polycarboxylic acid or anhydrides with polyhydroxylated alcohols, the unsaturation originating from olefinically unsaturated di- or polycarboxylic acids or anhydrides, acrylic or methacrylic acid and/or its esters, allyl compounds, or dicyclopentadiene, with molecular weights of between 2,000 and 15,000, the degree of branching being between 2 and 4,
• b) a curing agent consisting essentially of organic peroxide with a maximum curing temperature of between 140 and 190° C.;
• the relative proportions of resin and organic peroxides being 55-60% by weight of resin based on the final composition and 0.5-3.0% by weight of organic peroxide based on the final formulation.