Performance of Titanium Dioxide and Its Function and Application in Coatings

China Paint Online News Information
1. Classification and quality standards of pigment grade titanium dioxide
Titanium white powder pigments are divided into sharp titanium type and redstone type 2, according to international practice, respectively, called R-type and A-type. Untreated redstone and sharp titanium are called RI and AI, respectively. The post-treated redstone and sharp titanium types are called R2, R3 and A2, respectively. At present, the vast majority of the redstone titanium dioxide is R2 and R3, of which R2 sales accounted for more than 70%. R2 and R3 accounted for 77% and 22% of the redstone titanium dioxide used in coatings, respectively.models currently used in China are different from international practice. There are only 3 types of pigment titanium white powder, namely BA0101, BA0102 and BA0103. BA0101 and BA0102 are sharp titanium, BA0103 is redstone, BA0101 is untreated, BA0102 and BA0103 are post-treated. China's pigment titanium dioxide quality standards see GB / T1706-93.our standards and foreign standards are very different. In particular, there is only one model of redstone-type titanium dioxide, so that many newly developed, introduced and dedicated titanium dioxide varieties can not be used in contrast with the current standards in China. At the same time, China's production plants and users for a long time only in accordance with national standards to control and accept product quality, rather than according to user needs through the change process, to produce products to meet the different needs of customers. It is reported that China will soon introduce new standards.why do BA0102 sharp titanium and BA0103 redstone titanium dioxide have to be treated after coating? The reason is that after coating treatment, the water solution of titanium white powder is reduced, it is not easy to condense, the amount of oil absorption is reduced, and the whiteness, resistivity, antichromic force, covering force, pigment grinding dispersion, lacquer storage stability, paint film water resistance, light resistance, weather resistance and durability are improved, thereby improving the quality of titanium white powder.In our country, regardless of the use of sulfuric acid or chlorination method, the quality of prepared redstone-type titanium dioxide powder is worse than imported R1930 and R1902 and other gold-redstone-type titanium white powder, mainly manifested in low coloration, low cover, poor weather resistance, poor oil dispersion, high oil absorption. Therefore, the domestic gold-redstone type titanium dioxide powder still can not resist the competition of imported gold-redstone type titanium white powder, so that every year to import a large number of gold-redstone type titanium white powder.。 2. The performance and use of pigment grade titanium dioxide
Pigment grade titanium white powder has high refractive index, strong coloration, large cover, good dispersion, good whiteness, non-toxic, stable physical and chemical properties, and has excellent optical and electrical properties. Therefore, its use is very wide, coatings, plastics, paper, chemical fiber, ink, rubber, cosmetics, etc. should be used in pigment grade titanium dioxide. Among them, the largest amount of paint, about 57%. In particular, redstone-type titanium dioxide, most of the paint industry consumed. With the rapid rise of China's automotive industry, construction industry and water-based coatings, the coatings industry not only needs more titanium dioxide in quantity, but also requires higher quality and more varieties.refractive index of gold-redstone titanium dioxide was 2.76, and the refractive index of sharp titanium-type titanium dioxide was 2.55. The masking force is determined by the difference between the refractive index of the pigment and the refractive index of the medium, and their relative values can be calculated according to the formula. The reflectivity coefficient of goldstone-type titanium dioxide is 25% to 30% higher than that of sharp titanium-type titanium dioxide, which indicates that if the same cover is generated with sharp titanium-type titanium white powder, the amount of goldstone-type titanium dioxide can be reduced by 25% to 30%. In addition, the structure of gold-redstone-type titanium dioxide dense, relatively stable, small photochemical activity, can withstand ultraviolet light exposure, not easy to powder outside, weather resistance, gloss than sharp titanium-type titanium white powder. Therefore, widely used in a variety of high weather resistance of high-level ships, bridges, automobiles, buildings and other outdoor coatings, its use in the paint about 70%, and sharp titanium-type titanium dioxide easy to powder, easy to yellow, generally only used in indoor coatings or primers, its use only accounted for 30% of the paint used in titanium dioxide powder.。 3. The role of pigment grade titanium dioxide in coatings
coatings are thick suspensions consisting of substations, pigments, fillers, solvents and additives. It is coated on the surface of the object to form a tough coating film, the object plays a decorative and protective role.
paint in the coating has a certain cover force, it can not only cover the original color of the coating surface, but also to the film bright colors, to achieve beauty and decorative role. At the same time, pigments and fixants closely combined, integrated into one, can enhance the mechanical strength and adhesion of the coating film, prevent cracks, and can increase the thickness of the coating film, prevent ultraviolet and moisture penetration, improve the film aging resistance, extend the service life.Whether solvent-based or water-based paint, if the use of titanium dioxide, its role is not only to cover and decoration, the more important role is to improve the materialization of the coating performance, enhance chemical stability, to improve the cover, antichromic force, corrosion resistance, light resistance, weather resistance, enhance the mechanical strength and adhesion of the paint film, prevent cracks, prevent ultraviolet and moisture through, thereby delaying aging, extend the life of the paint film. At the same time, it can save materials and increase varieties.in pigments, white pigments are used most widely, white paints and light paints are used in it, so in the production of coatings, white pigments are much more used than other pigments. The white pigments commonly used in coatings are zinc white, zinc palladium white, titanium white and so on. Because some synthetic resin coating polymerization is large, if zinc white is added, it has a tendency to thicken due to the alkaline nature of zinc white, and the free fat anti-acid action in the coating; If zinc palladium is added, the weather resistance is poor. However, the use of titanium white can improve the above shortcomings. Because the titanium particles are small and uniform, the photochemical stability is high, in terms of cover force, the goldstone type of titanium white is 7 times the zinc white, is 5.56 times the zinc white, the sharp titanium type of titanium white is 5.57 times the zinc white, is 4.3 times the zinc white; In terms of antichroma, the redstone type of titanium white is 8.3 times that of zinc white, 6.25 times that of zinc white, and the sharp titanium type of titanium white is 6.4 times that of zinc white, and 4.8 times that of zinc white. In terms of use effect, 1t titanium white is equivalent to at least 4t zinc tantan; In terms of service life (refers to outdoor powder resistance), the coating of titanium white as pigment is 3 times higher than that of zinc tantan. Therefore, the use of titanium white can greatly reduce the amount of pigments in the entire coating, while the paint made of bright colors, not easy to yellow, light, heat, wear, weather, alkali, sulfur, thin acid. It is precisely because titanium white has superior performance than zinc white, zinc tanties, so that the paint production is essential to the best white pigments. Titanium white consumption accounted for more than 90% of the total amount of paint used in coatings, accounting for more than 95% of white pigments used in coatings. It accounts for 10% to 25% of the raw material cost of coatings.
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