| Mica titanium pearl pigment is one of the most representative in inorganic pearl pigments, which is the largest production and the most widely application of pearl pigments in the world. Because of its low manufacturing costs and well special metallic effect, are used extensively in the field of automotive and industrial coatings, plastics, rubber, ink, cosmetics and so on.In recent years, with people have been aware of the seriousness of environmental pollution and the environment protection law become more strict, environment protection has become an important global issue. The powder coating have the characteristics of high production efficiency, excellent film properties, eco-environmental protection and economy, which composed of 100% solid powder without solvent. Due to the variety of coating methods and convenient, powder coating has become one of the faster growing in the paint. At present, it has been mainly use in the automotive industry, electrical industry, and construction industry. But when the pearl pigment was used in powder coating to make the pearl powder coating, exist the phenomenon of low pearl pigment powder and separation serious after electrostatic spraying, make the bad effect of paint. Therefore, in order to make pearl pigment better applied to the powder coating, it is need to be surface modification.In this work, we adopted the traditional modified-wet process, using titanate coupling agent and surfacetant as modifier respectively, by comparing of the different modifiers and fertilizers, reaction temperature, reaction time, the dosage of modifier and electrostatic powder coating test experiment. In this paper, the two series of best formulation modification and process conditions were obtained:(1) the mica titanium pearl pigment were 5g, the dosage of isopropyl alchol 20mL, titanate coupling agent 4.0%, reaction temperature 60℃ and the time 1.5h, can obtain the best modification effect and the active index reached about 64%. (2) the mica titanium pearl pigment were 10g, the dosage of absolute ethyl alcohol 40mL, modifier stearic acid, optimal dosage 2.0%, clay slurry① additives, optimal dosage 4.0%, optimal reaction time 2h, optimal experimental temperature 70℃, and on this base, mica titanium pearl pigment with good dispersion and good the rate of powder properties were made. Compared with before and after modification, the treated samples with the better stability of the dispersion in organic solvent, mixing the treated pearl pigment and powder coating fully by dry-blending method or bonding process, then electrostatic spraying at 100KV,70KV and 40KV respectively, after comparing we can obtained conclusion:(1) The treated pearl pigment with higher powder rate at low voltage (40KV) spraying than at high voltage (70KV or 100KV) spraying; (2)the value of chromatism paint film were relative stability at the same voltage, when the pearl pigments were used in powder coating.By testing samples with FT-IR, SEM and XRD to analyze the titanate coupling agent and surfacetant modification mechanism, and the result shows that surface saturation exists during the modification process. Moreover, in order to verify the application of modified pearl pigment, put it into the powder coating mixed fully, than through electrostatic spraying and chromatic meter test, compared with the before and after modification effect.In conclusion, this work not only brings some useful information for the pearl pigments surface modification research, but also provide good references for the surface modification of pearl pigment powders in industry, and make the great significance of company’s production. |
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