The Optically Variable Mica Pigment Preparation And Study With Rare Earth Doped

Mica pearlescent pigment industry starts late in china, so there are many problems in mica pearlescent pigment products. For example, the pearlescent luster is poor, the color is not pure, the tone is not colorful and the fixation capability is bad, which bring many adverse influences in the application and quality of the Mica pearlescent pigment.In order to improve the quality of mica pearlescent pigment and enhance its lightness and color degree of saturation, Fe₂O₃-coated technology with the rare earth-doped was studied in the thesis. The technical condition included reaction temperature, initial pH, reaction time, the dosage of rare earth and urea, the speed of reagent adding, calcination temperature, calcination time, heating rate and so on. Through the experiments, the optimal condition was determined, and the optically variable mica pearlescent pigment was characterized by means of tristimulus colorimeter, XRD, IR, SEM and TG-DTA.As was showed in the results, the saturation of products reached 15.04 and tone angle was 75.90°by using urea neutralization and coating metal oxide without rare earth-doped; the saturation of products reached 21.20 and tone angle reached 51.06°by coating metal oxide with Er doped, after doping into Er, the saturation of products increased by 40.95%, tone angle decreased by 24.84°; the saturation of products reached 22.46 and tone angle reached 36.26°by coating metal oxide with the combination of Er-Nd-doped, after doping into Er and Nd, the saturation of products increased by 49.34%, tone angle decreased by 39.64°; the color of mica pearlescent pigment varied from intense red, rosiness to golden yellow, then adversely from silvery white, rosiness to intense red. The color was silvery white when the line of sight was at the total reflection angle and the tone would become dark gradually when the visual angle inclined from the total reflection angle to two sides.In order to appraise the property of mica pearlescent pigment, the acidity-resistant, the alkali-resistance, heat-resistant, light-resistant, solvents-resistant, heat-resistant and oil-adsorption were measured on mica pearlescent pigment. The results showed that the capability of acidity-resistant, alkali-resistance, light-resistant, solvents-resistant and aging-resistant was better; especially, the capability of solvents-resistant was the best; the capability of oil-resistant and heat-resistant was common; the oil-adsorption was 900g/100g pigment.The research results showed the color of mica pigment was more pure and brighter by doping rare-earth element. Superposed several films, the color of mica pigment would vary with the different angles. Along with the difference of film order and film color, the color-changing ranges of the mica pigment were different. There are many types of rare-earth elements and many combination-doping ways with the metal ion, so we can prepare optically variable mica pearlescent pigment with this method, which has the extremely broad research and the application prospect.