| 摘要 |
The present invention provides coating powders that enable excellent filiform corrosion resistance in clear or tinted clear coating comprising an epoxy functional acrylic copolymer component having a T g of from 40°C to 90°C and chosen from a copolymer or copolymer mixture that comprises, based on the total weight of copolymerized monomers in the epoxy functional acrylic copolymer component, i) from 10 to 40 wt.% of one or more epoxy functional unsaturated monomer, e.g. glycidyl (meth)acrylate; ii) from 2.0 wt.% to 13 wt.%, preferably 12 wt.% or less, or, more preferably, 6 wt.% or less, of one or more hydrophobic acrylic monomer that has a mass solubility in water of 3.5 g/L or less and which would itself form a homopolymer having a glass transition temperature (Tg) of 50°C to 175°C, e.g. a bicycloalkyl (meth)acrylate, and iii) the remainder of one or more nonionic comonomer that is not a hydrophobic acrylic monomer ii), e.g. methyl methacrylate; one or more crosslinker for the thermosetting acrylic copolymer; and, optionally, one or more adhesion promoter, e.g. epoxy resin, a light stabilizer, an ultraviolet (UV) absorber, and/or a hydrophobic submicron particle.
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