What will be the substitute of titanium dioxide, as it's classified as a carcinogen by EU

In the constant controversy, EU had classified titanium dioxide as a category 2 carcinogen officially in 18^th Feb 2020, which came with massive impact to paint industry and TiO2 market.

Although there are different opinions on this regulation, many enterprises have to figure out solutions as this regulation becomes effective in September 2020. Titanium dioxide is considered as the best white pigment in the world, along with expensive cost. There are abundant substitute pigment or filler existing around such as barium sulfate, calcium carbonate, Mica powder and so on. But, here is another theory TiO2 is irreplaceable due to its unique performance. With the development of nonmetal ore powder technology, the study of titanium dioxide substitution will not remain in the experimental stage.

How do TiO2 performance in paint?

Well, titanium dioxide is known as the best pigment in the world, due to its excellent whiteness, coloring power, covering power, weather resistance, heat resistance, and chemical stability, especially no toxicity. However, it’s expensive as many companies want to reduce the consumption of titanium dioxide. For example, In 2015, Akzo Nobel used only 7% of titanium dioxide raw materials, while resin accounted for 24%, additives accounted for 15%, chemicals and intermediates accounted for 22%, and solvents accounted for 9%. It is reported that Akzo Nobel will also significantly reduce the proportion of titanium dioxide raw materials.

Why barium sulfate precipitated?

Barium sulfate is not a pigment, but a filler. Barium sulfate precipitated, the particle size distribution is narrow, and the average particle size (D50) is about 0.35-0.4μm. it has the best glossiness, excellent whiteness and weather resistance. Special organic surface treatment gives it excellent dispersion. As the filler of pigment, it can improve the dispersion performance of pigment and improve the use efficiency of pigment. When the titanium dioxide is added in high proportion, the covering power is basically unchanged, and the glossiness of the products can be greatly improved.

How is the performance of barium sulfate precipitated in paint?

The advantages of using precipitated barium sulfate are as follows:

1. The precipitated barium sulfate can make the pigment disperse more evenly and improve the color developing efficiency of the pigment.

2. The refractive index of precipitated barium sulfate is 1.64, which is very close to the refractive index of most paint films, so it is almost transparent in the paint film, without covering power, and will not affect the color and hue of the pigment.

3. Using precipitated barium sulfate instead of some pigments in a proper range will not affect the color concentration and covering power of pure color paste and paint.

4. Adding a certain amount of precipitated barium sulfate to the pigment can fully extend the pigment particle crystal, prevent the flocculation and agglomeration of pigment particles, and reduce the amount of pigment added.

5. After the use of precipitated barium sulfate, the film leveling is very good, there is no bubble in the middle, and the fluidity of the paint is improved to a certain extent.

6. The precipitated barium sulfate is easy to disperse, and the high-speed dispersion can be achieved by choosing the appropriate dispersant (preferably by sanding).

7. Compared with other inorganic pigments, precipitated barium sulfate will not cause precipitation and physical stratification of the final product.

8. Using precipitated barium sulfate can not only improve the thickness and glossiness of the film, but also increase the scratch resistance of the film surface.

9. The precipitated barium sulfate has a certain anti floating effect, but the effect is not obvious when the amount is small.