Among the weather-resistant powder coatings, polyurethane powder coatings are second only to polyester powder coatings in the world in terms of production. With many excellent properties, its coating film has high gloss, excellent decorative properties, strong wear resistance, good adhesion, and at the same time has good weather resistance, corrosion resistance, electrical properties and mechanical properties, it can be said that it takes into account the advantages of epoxy and acrylic powder coatings, and has the advantage of non-toxic than pure polyester powder coatings.
Schematic diagram of the effect of adhesion promoters on the surface of metal substrates or metal pigments.
Schematic diagram of the effect of adhesion promoters on the surface of metal substrates or metal pigments 1. Metal substrate adhesion promoters
When aluminum is exposed to the atmosphere, a thin layer of aluminum oxide is formed on the surface. This aluminum oxide layer has anti-corrosion properties, and because of its electrical insulation properties, it is usually difficult to adhere in solvent-based coating systems. Similar situations Including non-ferrous metal substrates, such as aluminum, aluminum alloy, zinc, stainless steel, electroplated surfaces, etc., usually polyester amino baking paint, acrylic amino baking paint or even special resin base materials must be used to obtain good adhesion. However, this will increase the cost. For this reason, we can use Ad-he rant ADP similar to Deqian Company, which is a high-molecular adhesion promoter. Adhesion of iron metal.
Adhesion promoters such as Adhe rant ADP are added to the baking paint. After coating, due to the adsorption of ionic potential, it can migrate quickly to the surface of the substrate and form a chemical bond with the metal substrate during high-temperature baking. At the same time, it also Cross-linking reaction with general amino baking paint system to achieve the effect of adhesion promotion. paraffin wax and ptfe Table 21-8 is the white alkyd amino baking paint formula; Table 21-9 is the white drunk amino baking paint performance test results after adding Ad he rant ADP, especially the adhesion promotion effect on aluminum is obvious.
Diluent: xylene/isobutanol=4/1 (mass ratio).
Adhesion test: Dilute with thinner to spray viscosity (No. 4 Ford Cup: 12s), spray on aluminum plate and bake and solidify, and perform performance test after cooling.
Tests have shown that this type of adhesion promoter can significantly improve the adhesion of general alkyd amino baking paints to aluminum and other non-ferrous metals. Because this type of adhesion promoter is a polymer compound, it can interact with various alkyd, acrylic or poly Ester resins and even amino resins may have problems with miscibility, so a miscibility test should be carried out before use.
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