The effect of titanium dioxide on coating cover is discussed.

to explore the effect of titanium dioxide on coating cover
Jane Yanhong1, Chen Yanyao 2, Chen Mingyi 1 (1. Guangdong Shunde San and Chemical Co., Ltd., Guangdong Foshan 528325; 2. Guangdong San and Chemical Technology Co., Ltd., Guangdong Zhongshan 528429) 0 Foreword
Among many white pigments, titanium dioxide powder is widely used in coatings, inks, rubber, papermaking, enamel and other industries, closely related to people's lives. In China, the application of titanium dioxide in the field of coatings occupies a considerable proportion, and in the coating titanium dioxide also has a certain impact on the various properties of coatings.
the coating is an important technical index of coatings, and titanium dioxide is one of the decisive factors of this index. Titanium dioxide is widely used in various fields because of its excellent optical properties, titanium dioxide is used in the coating industry, in order to make tiO2 optical properties play full, it is necessary to titanium dioxide surface treatment, particle size distribution, dispersion performance and other fine control. While using titanium dioxide efficiently, the researchers are also working to reduce the amount of titanium dioxide while maintaining cover. This paper focuses on the effects of coating coating treatment, particle size distribution and dispersion in water on coating cover.1 Titanium White Powder Production Overview
Currently, titanium dioxide production is mainly chlorinated and sulfuric acid. In 1918, the researchers used sulfuric acid to break down titanium iron ore or acid-soluble titanium slag into TiOSO4 solution, and then de-miscellaneous, separation, so that the method of producing titanium dioxide - sulphuric acid method, because of the earlier discovery time, the sulfuric acid process is relatively mature. Chlorination method through titanium-rich raw materials and chlorine gas reaction, the resulting titanium tetrachloride through refined gas phase oxidation to obtain coarse titanium dioxide, and then after treatment of titanium dioxide to obtain high-quality titanium dioxide white powder, chlorinated legal preparation titanium dioxide process is relatively short.2 Effect of surface treatment on cover force
The structure of TiO2, a titanium dioxide powder used in coatings, has a strong photo catalytic activity and is easily powdered after exposure to ultraviolet light, affecting its application in coatings. Therefore, titanium dioxide is usually used on its surface for one or more layers of porous silicon, aluminum oxide package, which not only solves the problem caused by the photo catalytic activity of titanium dioxide, but also makes the coating clearance rate increase, when the light shines on the coating, through the repeated refraction of the multi-porous coating interface, greatly increasing the coating cover. It can be seen that by coating the surface of titanium dioxide, the properties of the coating can be improved to a great extent.
now, titanium dioxide coating process in China has made great progress, but compared with foreign countries there is still a certain gap, such as high-end titanium dioxide market for most foreign products. At present, china should pay attention to the research on the theory of inorbic cladding of titanium dioxide, the enhancement of the adaptability of titanium dioxide products to the system and the development of new cladding agents, so as to promote the development of titanium dioxide in China into a new stage.3 Titanium white powder particle size
Titanium white powder particle shape and size of different, the degree of scattering of light is very different, is a key factor affecting the titanium white powder cover. The research shows that under the same conditions, when the particle size of titanium dioxide is 160 to 350nm, i.e. the particle size is about 0.4 to 0.5 times the wavelength of visible light, it has a strong scattering ability to light, which will directly affect the covering force of the coating in the application. In the coating system, if the film material is not enough to completely cover the titanium dioxide particles, it will make the titanium dioxide particles contact with each other, reunion, to some extent equivalent to the increase of titanium white powder particle size, and make the coating cover decreased.4 titanium powder dispersion
in the field of coatings, the degree of dispersion of powder particles to a large extent determines product performance. In the production of the coating, the dispersion of titanium dioxide to go through the wetting, sanding and dispersion process, people expect titanium dioxide can be in the paint in a stable suspended state, however, because titanium white powder has a certain activity, the use of the system environment for its dispersion will have a certain impact, thus showing such as flocculation, precipitation, suspension and other dispersed state. The following discusses the effect of dispersant dosage and sanding time on coating cover.
4.1 Dispersant Dosage
Titanium white powder in dispersion, because its particles are relatively small than fillers, tend to particle condensation, so the choice and dosage of dispersants will affect the dispersion of titanium dioxide, while affecting the covering force of the paint film. Experiments show that the dispersion degree of pigment increases with the increase of dispersant dosage, and the dispersion increase makes the distribution range of pigment particle size narrow and the particle size become smaller, so that the covering power of paint film is improved.
4.2 Dispersion Time
If titanium dioxide is to be dispersed by high quality in the coating system, high-speed dispersion or sanding is a necessary process, the aim is to reduce the particle size of titanium dioxide to increase the surface performance of the coating. The reduction of particle size helps to improve the coating cover, so the length of dispersion time determines the dispersion efficiency of titanium dioxide. According to the experiments of the researchers, different dispersant dosage, titanium dioxide status and dosage, PVC values are different, the dispersion sanding time of titanium white powder is not the same, in the production of coatings need to be based on the system of titanium white powder dispersion time to make corresponding adjustments to achieve the best dispersion effect.5 Titanium dioxide development
With the improvement of social awareness of environmental protection, user demand for product quality increased, titanium dioxide production methods are gradually based on chlorination, China's titanium dioxide industry in the production process has also made a major breakthrough, promoting the transformation of scientific and technological achievements to real productivity. However, the current lack of domestic titanium raw materials resources, titanium dioxide production depends on a large number of imported titanium raw materials, coupled with China's suitable for chlorination production of titanium raw materials reserves are very small, too slag production capacity is weak, such as a series of problems seriously hinder china's titanium dioxide production. At present, the demand for titanium dioxide in various industries is increasing day by day, research and development personnel are committed to the development of alternative products of titanium dioxide, such as inororable pigments and titanium dioxide combined into a composite pigment is being paid attention to, I believe that the titanium dioxide industry will eventually create more economic benefits..