Frequently asked questions

Whiteness

Definition:Whiteness reflects the light-reflecting capability of titanium dioxide and is one of the key indicators of its performance as a white pigment.
Key Factors Affecting Whiteness:

TiO₂ Purity: Higher TiO₂ content and lower impurity levels result in better whiteness.

Surface Treatment: Optimized inorganic and organic surface coatings help minimize stray light interference and enhance whiteness.

Crystal Structure: Rutile titanium dioxide generally exhibits higher whiteness than anatase titanium dioxide.

Hiding Power

Definition:Hiding power is the ability of a pigment to obscure the color of the underlying substrate. For titanium dioxide, it reflects its effectiveness in enhancing the opacity of a white coating film.
Key Factors Affecting Hiding Power:Particle size, particle structure, and dispersion quality all have a direct impact on hiding power. Titanium dioxide with an optimized particle size, smooth particle morphology, and excellent dispersibility provides superior hiding power.
Test Standard:GB/T 5211.17-1988 White Pigments—Comparison of Contrast Ratio (Hiding Power).

Weather Resistance

Definition:Weather resistance refers to the ability of titanium dioxide-containing organic materials, such as coatings and plastics, to resist yellowing, gloss loss, and chalking when exposed to sunlight and outdoor weathering. It includes color retention, gloss retention, and resistance to chalking, making it a critical property for exterior applications.

Advantage of Rutile Titanium Dioxide:Compared with anatase titanium dioxide, rutile titanium dioxide more effectively absorbs ultraviolet (UV) radiation and dissipates the absorbed energy as heat, thereby protecting the coating film from photodegradation and significantly improving outdoor durability.

Enhancement Measures:Advanced inorganic and organic surface treatment technologies can significantly improve the weather resistance of titanium dioxide by reducing photocatalytic activity, minimizing chalking, and maintaining the integrity of the coating film during long-term outdoor exposure.

Dispersibility

Definition:Dispersibility is the ability of titanium dioxide particles to be rapidly and uniformly dispersed in a given formulation, enabling the pigment to achieve its optimum particle size distribution and performance.

Key Factors Affecting Dispersibility:Titanium dioxide particles with a primary particle size below 0.5 μm tend to form secondary agglomerates due to strong interparticle forces. Poor dispersion can reduce hiding power, gloss, color development, and processing efficiency. Advanced inorganic and organic surface treatments help prevent agglomeration, improve wetting and dispersion, and ensure consistent performance in coatings, plastics, inks, and paper.

Test Standard:GB/T 21867.2-2008 Pigments and Extenders—Evaluation of Dispersibility—Part 2: Assessment from the Change in Fineness of Grind.

Tinting Strength

Definition:Tinting strength is a measure of the ability of titanium dioxide to influence the color of a pigmented system when mixed with colored pigments. It indicates the effectiveness of the pigment in producing the required degree of lightening or color modification.

Key Factors Affecting Tinting Strength:Tinting strength depends mainly on particle size, particle size distribution, refractive index, crystal structure, and dispersion quality. Titanium dioxide with an optimized particle size and narrow particle size distribution offers superior light scattering, resulting in higher tinting strength.

Application Significance:

Titanium dioxide with high tinting strength improves color development and consistency while reducing pigment consumption. It is particularly important for architectural coatings, industrial coatings, plastics, inks, and masterbatches where accurate color control and cost efficiency are required.

Photocatalytic Activity and Weathering Mechanism

Intrinsic Photocatalytic Activity:Titanium dioxide is a semiconductor material with inherent photocatalytic activity. It exhibits slight absorption in the short-wavelength region of the visible spectrum and the ultraviolet region. When exposed to UV light, titanium dioxide can act as a photocatalyst, generating reactive species that accelerate the degradation of organic binders in coatings and plastics. This effect mainly occurs under light with wavelengths below approximately 405 nm.

Solar Ultraviolet Radiation:Solar radiation reaching the Earth's surface contains only a portion of the ultraviolet spectrum. During transmission through the atmosphere, nearly all UV radiation with wavelengths below 300 nm is absorbed by the ozone layer and atmospheric gases. Therefore, the UV wavelengths primarily responsible for outdoor weathering are in the range of 300–400 nm.

Crystal Lattice Defects:Crystal lattice defects, such as Schottky defects (oxygen vacancies) and other structural imperfections, can increase the photocatalytic activity of titanium dioxide by acting as charge-trapping sites. These defects promote the formation of reactive oxygen species, thereby accelerating the degradation of surrounding organic materials.

Effect on Coatings：The photocatalytic activity of titanium dioxide may accelerate the degradation of the binder in coating systems, leading to:Accelerated weathering and aging,Reduced weather resistance,Loss of gloss,Color fading or yellowing,Surface chalking,Shortened service life of the coating.

Technical Note:Rutile titanium dioxide with optimized inorganic (Al₂O₃, SiO₂, ZrO₂) and organic surface treatments exhibits substantially lower photocatalytic activity than untreated or anatase titanium dioxide, providing superior weather resistance for high-performance exterior coatings, plastics, and other outdoor applications.

Gloss

Definition:Gloss is a measure of a coating surface's ability to reflect light in a specular direction. It is an important optical property that contributes to the visual appearance of coatings, plastics, and inks.

Key Factors Affecting Gloss:Gloss is primarily influenced by the dispersion quality of titanium dioxide, particle size distribution, and the smoothness of the cured coating film. Excellent pigment dispersion and optimized film formation promote a smooth surface, resulting in higher gloss and improved appearance.

Application Significance:Titanium dioxide with excellent dispersibility helps achieve uniform film formation, enhances gloss development, and provides a high-quality surface finish, particularly in high-gloss industrial and architectural coatings.

Gloss