Titanium dioxide is the most important white pigment, which has high refractive index, good chemical stability, weather resistance, whiteness, high achromatic power and hiding power, non-toxic and harmless, and has no irritating effect on human body. it is widely used in coatings, plastics, papermaking, ink, medicine, fiber, cosmetics and other fields.
Paint is the largest user of titanium dioxide. In general, the consumption of titanium dioxide in the coating field accounts for 60% of the consumption in the application field of titanium dioxide, and it is also one of the most used pigments in coatings (titanium dioxide accounts for 10% 35% of all kinds of coatings).
Latex paint: rutile titanium dioxide must be used for external coatings and anatase titanium dioxide for internal coatings.
Coil and printing iron coating: coil coating can be divided into inner coating and surface coating, the requirement of inner coating is low, domestic rutile titanium dioxide and epoxy resin can be used, and the requirement of surface coating is high. generally, imported rutile titanium dioxide and polyester resin are used.
Automotive paint: automotive paint mainly requires the weather resistance, gloss and hiding power of titanium dioxide. At present, there are few brands of titanium dioxide that can be used in car paint, all of which are special imported rutile titanium dioxide by chlorination process, such as R2310, R706 and so on. At present, domestic rutile titanium dioxide can only occupy the market of medium-and low-grade automotive paint.
Powder coatings: rutile titanium dioxide is mostly used in powder coatings.
The plastic industry is the second largest user of titanium dioxide, and usually the consumption of titanium dioxide in the plastic field accounts for 20% of the consumption in the application field of titanium dioxide. Among the more than 500 brands of titanium dioxide in the world, more than 50 are dedicated to plastics.
The application of titanium dioxide in plastic products, in addition to making use of its high hiding power, high achromatic power and other pigment properties, it can also improve the heat resistance, light resistance and weather resistance of plastic products and protect plastic products from ultraviolet light. improve the mechanical and electrical properties of plastic products. Titanium dioxide is used in almost all thermosets and thermoplastics, with a general dosage of 1% to 5%. It can be mixed with either dry resin powder or liquid containing plasticizers, and titanium dioxide is processed into a color masterbatch before use.
The particle size of titanium dioxide for most plastics is fine (0.15-0.3 μ m), which can obtain a blue background color, which can mask most yellowing resins or yellowing resins.
Titanium dioxide for plastics is generally treated by organic (polyol, silane or siloxane) surface treatment. the treated titanium dioxide can be well dispersed under appropriate mechanical shear force.
The quality requirements of titanium dioxide for plastic products are as follows:
Weather resistance: outdoor plastic products and plastic doors and windows must ensure the weather resistance of titanium dioxide;
Whiteness: determine the appearance of light-colored or white plastic products;
Dispersion: affect the production cost of plastic products, poor dispersion of titanium dioxide in plastic products will affect the smoothness and brightness of products;
Hiding power: titanium dioxide with good hiding power, the plastic products produced are lighter and thinner.
(3) Color masterbatch.
Plastic color masterbatch is a kind of color matching product with high concentration and high efficiency. according to incomplete statistics, the amount of titanium dioxide used in the production of color masterbatch in China is 20-30,000 tons per year.
The performance of color masterbatch is usually shown in subsequent product applications, such as film blowing or injection molding. therefore, the performance of titanium dioxide in color masterbatch is mainly reflected in the application process of color masterbatch:
Coloring power: determine the amount of titanium dioxide used in plastic products of the same color;
Whiteness and color difference: determine the appearance of light-colored (white) plastic products with the same content of titanium dioxide;
Dispersibility: affect the production cost of color masterbatch and the appearance and luster of plastic products;
Processability: affects the production cost of color masterbatch.
Papermaking is the third largest user of titanium dioxide. Titanium dioxide is generally used in decorative paper, biblical paper and banknotes, and the paper with titanium dioxide has good whiteness, high strength, glossy, thin and smooth, and does not penetrate when printing. under the same conditions, the opacity is 10 times higher than that of calcium carbonate and talcum powder, and the quality can be reduced by 15% and 30%.
Decorative paper, also known as titanium dioxide paper, is mainly used to make raw materials such as furniture, floor, wallpaper and so on. For paper with anti-aging requirements, rutile titanium dioxide must be used; more rutile titanium dioxide is used in high ash paper, because the hiding power of anatase titanium dioxide can not meet the requirements. Anatase titanium dioxide is used for low-ash paper, such as Bible paper and banknotes.
According to incomplete estimates, the amount of titanium dioxide used for decorative paper in China is more than 30,000 tons per year. The amount of titanium dioxide used in decorative paper is 20% Mel 40%, and the amount of titanium dioxide in other paper is 1% Mel 5%. The main reason for deciding what kind of titanium dioxide is chosen by the paper mill is the cost of papermaking, that is, the performance-to-price ratio of titanium dioxide. Can use anatase titanium dioxide never use rutile titanium dioxide.
The order of requirements for the quality of titanium dioxide in the paper industry is as follows: hiding power (opacity), whiteness, dispersibility, weather resistance, retention rate.