Paint coatings continued methods

Unlike coatings made from thermoplastic powders which require only a visual inspection to see whether the coating is satisfactory, thermosetting powder coatings require additional examination to determine whether the coating has achieved its full physical properties. Simple mechanical tests may be used, as is the practice with conventional paint finishes, but, particularly for epoxy powder coatings, it is normal to use chemical resistance as a criterion for suitability. A common method is to swab the coating continuously for 30 seconds with a cotton wool pad soaked in methyl isobutyl ketone. Any deterioration of... 

Curtain coating With this process, paint falls in a continuous curtain from a closely machined gap in a header tank on to the flat article passing below on a horizontal conveyor the excess paint is collected in the main tank and then passed up to the header tank. It is an ideal method of applying thicker coatings (60/im and above) to sheet metalwork. 

Specification for electroplated coatings of 65/35 tin/nickel alloy Method for the evaluation of results of accelerated corrosion tests on metallic coatings Methods of test for paints Cross-cut test Pull-off test for adhesion Resistance to artificial weathering (enclosed carbon arc) and Addendum No. 1 Resistance to continuous salt spray Notes for guidance on the conduct of natural weathering test... 

Infrared. Batch or continuous operation. Electric heating or gas-fired Only for thin films. Can be used in combination with other dryers such as drum. See comments under Liquids. See comments under Liquids (only for thin layers). Only for thin layers Primarily suited to drying surface moisture. Not suited for thick layers Specially suited for drying and baking paint and enamels Useful when space is limited. Usually used in conjunction with other methods, e.g., in drying paper coatings Useful for laboratory work or in conjunction with other methods... 

Electrodeposition (1882) vt. Method of paint application in which an article to be coated which is an electrical conductor is made one of the electrodes in a tank of water-thinned paint. The other electrode is generally a metal such as copper. The two electrodes are connected to a source of electric power, the polarity of the article to be coated being of the opposite sign to that on the particles in the liquid paint in the tank. The charged particles move towards the articles under the influence of the electric field, and when they give up their charge at the electrode (article) they are deposited and ultimately form a continuous film of paint. Weismantal GF (1981) Paint handbook. McGraw-Hill Corporation Inc., New York. 

Vinyl resins - In the coatings industry, vinyl resins usually refer to either poly(vinyl chloride) (PVC) or poly(vinyl acetate) (PVAc) which is widely used in interior and exterior latex paints. Produced usually by emulsion polymerization, a PVAc homopolymer is too hard to allow its colloidal latex particles to coalesce well into a continuous film at ambient temperatures. Most PVAc emulsions used in the paint industry are copolymers with a plasticizing monomer such as dibutyl maleate, 2-ethyhexyl acrylate, n-butyl acrylate, dibutyl fumarate, isodecyl acrylate, or ethyl acrylate. By polymerizing under pressure, copolymers of vinyl acetate and ethylene are also produced for latex paints. External plasticizers such as dibutyl phthalate are used as well. All these methods not only soften the polymer to allow the latex particles to coalesce into a continuous film, but also impart the film flexiblity needed in exterior house paints. 

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