Processo de sulfato vs. cloreto de dióxido de titânio: qual é melhor para revestimentos?
A indústria de revestimentos é a maior consumidora de dióxido de titânio (TiO₂), especialmente o dióxido de titânio do tipo rutilo, sendo a maior parte consumida pelo setor de tintas e revestimentos. Globalmente, o consumo de TiO₂ pela indústria de revestimentos representa cerca de 58%–60% do consumo total de pigmentos de dióxido de titânio. Na China, essa proporção é ainda maior, em torno de 60%–65%. O dióxido de titânio é o pigmento mais utilizado na indústria de revestimentos, respondendo por metade dos custos com pigmentos e aproximadamente 90% do consumo total de pigmentos na indústria. Ele também representa cerca de 10%–25% dos custos de matéria-prima em revestimentos.
Depending on the specific performance requirements of different types of coatings, properties such as weather resistance, hiding power, appearance, and dispersibility of titanium dioxide are critical. The performance of titanium dioxide produced by the two different processes—the sulphate process and the chloride process—can be compared as follows:
- In terms of usage, sulphate-process rutile titanium dioxide typically requires 5% to 15% more quantity compared to chloride-process rutile titanium dioxide.
- In terms of dispersibility, sulphate-process rutile titanium dioxide is approximately 10% inferior to chloride-process rutile titanium dioxide.
- In terms of hiding power, chloride-process rutile titanium dioxide has 10% to 15% higher hiding efficiency compared to sulphate-process rutile titanium dioxide.
- In surface properties, flowability, yellowing resistance, and color stability, chloride-process rutile titanium dioxide also outperforms sulphate-process products.
Therefore, it is very important for customers to select the titanium dioxide variety that meets the performance requirements of their coatings and finished films. From the comparison, it is clear that currently, the best titanium dioxide is the rutile type produced by the chloride process. It is the highest-quality white pigment available on the market, offering excellent overall performance, making it the first choice for coatings, and an essential pigment for light-colored paints.
Due to differences in surface treatment processes, there are various grades of titanium dioxide available. Specific grades can be selected according to the characteristics of the coating being formulated, such as whether high gloss, high hiding power, or high chalking resistance is required.
Titanium dioxide produced by the sulphate process has a lower anatase-to-rutile phase transformation rate compared to the chloride process, resulting in slightly lower whiteness and light stability. However, it comes at a lower price point.or expert advice.
