Application Of Environmental Friendly Inorganic Pigment Cobalt Blue In Plastic And Color Masterbatch

Environmental friendly inorganic pigment is an emerging class ofinorganic pigments which can meet the needs of human about environmentand health. The characteristics of these pigments are that the composition doesnot contain elements and chemicals which are harmful to human andenvironment, and those pigments can be used to color the plastics which areclosely contacted with human. The most important environmental friendlyinorganic pigments is environment-friendly color miscible inorganic pigmentswhich include cobalt blue spinel, cobalt green spinel, titanium nickel yellowrutil, titanium chrome brown rutil, copper chromite black spinel, iron zincchromite brown spinel and etc. At present, the research about application ofenvironmental friendly inorganic pigment in plastic and color masterbatch hasbeen rarely reported.In the paper, a lot of work has been done about cobalt blue which is oneof environmental friendly inorganic pigments, and found that the differencesbetween domestic and foreign cobalt blue pigments in plastic and colormasterbatch.The performances of domestic and foreign cobalt blue pigments were tested by scanning electron microscopy, the Zeta particle size analyzer,X-ray diffraction, X-ray spectrometer, integrating sphere color measurementinstrument and etc. The results were that domestic cobalt blue pigment’stinting strength and color saturation were lower than foreign products, and thecontent of cobalt element in the surface of the pigment was also lower, whilethe integrity crystal grain of the pigment was not as good as foreign pigment,and at the same time the distribution uniformity of pigment particles was notas good as foreign pigment.Cobalt blue pigment was applied to plastics and color masterbatch whichwere tested by integrating sphere color measurement instrument, opticalmicroscope and the melt index meter. The results were that the tinting strengthand color saturation of domestic cobalt blue was worse than foreign cobaltblue at low concentrations, but when the content of pigment reached1.2%, thedomestic cobalt blue pigment’tinting strength and color saturation can beachieved much better than the same concentration of foreign cobalt bluepigment. When the dispersant was5%in the preparation of cobalt bluemasterbatch, the covering and dispersion of coloring film was the best, but theforeign cobalt blue coloring film was better than the domestic one. Comparedto the masterbatch processing flow properties, the melt index of the foreignpigment masterbatch was higher than the domestic pigment masterbatch, sothe foreign pigment masterbatch got better performance of processing flow. Comparisons of several of fillers were applied in cobalt blue color masterbatch, and the coloring performance was studied on different types ofinorganic fillers in color masterbatch. For the selection of attapulgite,nano-calcium carbonate, nano-barium sulfate and titanium dioxide, the resultsshowed that only by adding titanium dioxide could improve the coloringperformance of cobalt blue masterbatch. And when added1%titanium dioxidein cobalt blue masterbatch could improve the tinting strength and colorsaturation, while overdose the effects would been declined.