| 摘要 |
<p>1496200 Coated substrates FORD MOTOR CO Ltd 30 Oct 1975 [20 Dec 1974] 44882/75 Heading B2E A substrate, e.g. steel treated by cleaning, phosphating and conventional primer is coated with a first coating of an aqueous dispersion comprising 6-60 parts particulate pigment, e.g. aluminium flake, carbon black or titanium dioxide and 40-90 parts thermosetting binder resin, at least partially curing the first coating, applying a second coating of a particulate film forming material and heating the substrate to convert the second coating to a continuous transparent coating. Partial curing may be by heating from 200-350‹F, more preferably 225-275‹F. The final heating may be from 300 to 350‹F or 325-350‹F for 15 to 30 minutes. The first coat may employ a mixture of a low molecular weight emulsion polymer and a low molecular weight solution polymer. The solution polymer may be a copolymer of acrylic or methacrylic acid. Suitable comonomers include styrene, alpha methyl styrene, t-butyl styrene, vinyl toluene, vinyl chloride, acrylonitrile, methacrylonitrile and vinyl acetate. Alkyl and hydroxyl alkyl acrylates and methacrylates may be included. The emulsion polymer is preferably a copolymer of acrylic or methacrylic acid. The polymers may include a cross linking agent, e.g. urea formaldehyde or melamine formaldehyde resin. The powder coating material may be a thermosetting or thermoplastic material. Suitable polymers include epoxy group containing polymers of acrylates and methacrylates. polyesters, polyepoxides, urethane modified poly, esters, polyepoxides and acrylics. Comonomers as described for the first coating may be employed. The coatings may be applied by spraying, preferably by electrostatic spraying. Two tone car bodies may be produced by this method.</p> |
