(1) Requirements of the coating on the performance of titanium dioxide

The coating industry is the largest user of titanium dioxide, especially rutile titanium dioxide, most of which is consumed by the coating industry. The global coating industry consumes 58% ~ 60% of the total consumption of titanium dioxide pigment, and the proportion of this consumption in China is higher, about 60% ~ 65%. Titanium dioxide is a pigment with the largest amount in the coating industry, accounting for half of the cost of pigment, 90% of the total pigment consumption in the coating industry, and 10%~25% of the raw material cost of the coating. White pigments are too numerous to enumerate, why paint over the years but only in favor of titanium? This is mainly because titanium dioxide is far superior to other white pigments in various main properties.

Titanium dioxide has the highest refraction coefficient, so it has the highest covering power (opacity) and achromatic power and other optical properties, bright whiteness, high gloss and good dispersion. Theoretically speaking, rutile titanium dioxide is 5.56 times that of ordinary Lithopone, anatase titanium dioxide is 4.43 times that of ordinary lithopone in terms of covering power. In the aspect of extinction power, rutile titanium dioxide is 6.25 times of Lithopone, anatase titanium dioxide is 5.56 times of lithopone. Therefore, from the use effect alone, 1 ton of titanium dioxide is equivalent to at least 4 tons of ordinary Lithopone; In terms of service life (mainly refers to the outdoor anti-powdery), the coating with titanium dioxide pigment is 3 times higher than that with ordinary Lithopone pigment, which is the reason why the paint has been chosen titanium dioxide for a long time.

Titanium dioxide is one of the indispensable components of the coating, its role is not only to cover and decorative, more important is to improve the physical and chemical properties of the coating, improve the mechanical strength, adhesion, corrosion resistance, light resistance and weather resistance. Therefore, the application of titanium dioxide in addition to from the base material, solvent, additives and other aspects of consideration, at the same time from the pigment characteristics, paint performance and other aspects to consider, a reasonable choice of suitable for the performance of the coating titanium dioxide varieties and specifications. Pigment grade titanium dioxide is usually used in the coating industry, and its quality requirements for titanium dioxide are: 1. whiteness should be enough; 2. good grinding wettability, easy to disperse; 3. Good weather resistance and durability; 4. Good chemical stability; 5. Small particle size, large covering power, high achromatic power, good opacity and glossiness.

(2) Comparison of application of titanium dioxide of two processes in coatings

Based on the use characteristics of different coatings, there are different requirements on the weatherability, covering power, aesthetics and dispersion of titanium dioxide.

According to the requirement of coating performance, it is very important to select the titanium dioxide that can meet the requirement of coating and film performance.

Rutile chloride production is the best product, is the best white pigment in the current market, its comprehensive performance is excellent, is the first choice of white pigment in the paint, is also the color of light paint. As a result of the different surface treatment technology, titanium dioxide has different models, can be prepared according to the characteristics of the paint, such as whether the requirements of high gloss, or high covering force, or high resistance to powdery, select the specific variety. Rutile type titanium dioxide produced by sulfuric acid production process, because the anatase to rutile type conversion rate is lower than the method of chloride, so the whiteness of the product and the stability of the light is slightly worse than the method of chloride, but the price is lower.

To be continued