The Role of Titanium Dioxide in Rubber Products

Titanium dioxide (commonly known as titanium white) is an important member of the inorganic filler family that combines functional and general properties. It is gradually shedding the traditional perception of being used "only for coloring" in the rubber industry. In the research and production process of rubber products, it has become a core element connecting product appearance with long-term performance, with its diverse value far exceeding that of a single-function additive. Compared to carbon black, which primarily serves a reinforcing role, and ordinary inorganic fillers, which focus on cost control, titanium white offers excellent whiteness and covering ability, providing irreplaceable appearance optimization solutions for light-colored and white rubber products such as medical gloves, tire sidewalls, and home appliance seals. The following article will comprehensively analyze the various core functional principles of titanium white in rubber formulation systems.

In terms of tinting capabilities, titanium dioxide has outstanding advantages. Firstly, it is recognized globally as a top-performing white pigment, possessing extremely high whiteness and gloss. In the production of products such as white rubber hoses and colored rubber shoe soles, titanium dioxide can make the products exhibit bright and pure colors, meeting the market's diverse demands for the appearance of rubber products. Secondly, it demonstrates excellent covering power, effectively masking the color of the raw rubber materials or impurities mixed during the production process, ensuring the final product has a uniform and consistent color. Among these, rutile titanium dioxide is particularly notable for its dense structure, strong stability, low optical activity, and good weather resistance. Not only does it offer higher covering and decolorizing power, but it also helps rubber products resist the effects of sunlight and atmospheric conditions, preventing issues such as discoloration, chalking, and loss of gloss. Therefore, it is widely used in rubber products with strict weather resistance requirements, such as automobile tires.

According to the Color Masterbatch Industry Network, titanium dioxide plays a crucial reinforcing role in rubber formulations. In terms of enhancing mechanical properties, the addition of titanium dioxide can significantly improve the mechanical indicators of rubber. For example, in polysulfide sealants, as the amount of titanium dioxide increases, both the hardness and tensile strength of the sealant increase simultaneously. In studies on room temperature vulcanized silicone rubber (RTV-SR) composites, it has been found that smaller particle sizes and larger specific surface areas of TiO₂ particles can further enhance the mechanical properties of the composite, such as compressive modulus and fracture strain. From the perspective of enhancing structural stability, titanium dioxide particles can be uniformly dispersed within the rubber matrix and interact with rubber molecules to form a network-like structure. This structure allows the rubber to more efficiently distribute stress when subjected to external forces, reducing the formation and propagation of internal defects and cracks, thereby improving the durability and reliability of rubber products.

The anti-aging effect is also an important value of titanium dioxide in the rubber industry. On one hand, rubber products exposed to sunlight for a long time suffer from ultraviolet (UV) radiation, which causes the rubber molecular chains to break and cross-link, leading to aging and performance degradation. Titanium dioxide can absorb and scatter ultraviolet rays, significantly reducing their damage to rubber molecules. For example, after adding surface-modified TiO₂ nanoparticles to silicone rubber, its stability against ultraviolet-C (UV-C) radiation is significantly enhanced, and the aging process is noticeably delayed. On the other hand, by inhibiting oxidation reactions initiated by ultraviolet rays, titanium dioxide can slow down the aging speed of rubber products, maintaining their physical and chemical properties and extending their service life. For products such as automobile tires and outdoor rubber seals that are exposed to harsh environments for extended periods, this function of titanium dioxide ensures their long-term stable operation.

As an inorganic filler, titanium dioxide also possesses filling functions. In terms of cost reduction, titanium dioxide is relatively affordable. When added appropriately to rubber formulations, it can reduce the amount of expensive rubber raw materials used, thereby lowering overall production costs and enhancing the product's market competitiveness. Additionally, it can adjust the density and hardness of the rubber according to requirements, making it suitable for different applications. In terms of improving processing performance, appropriate filling with titanium dioxide can optimize the processing characteristics of rubber, such as enhancing the flowability of the compound and reducing energy consumption during the mixing process. During the mixing stage, titanium dioxide is evenly dispersed in the rubber matrix, making the compound more uniform and stable, which creates favorable conditions for subsequent molding processes, thereby increasing production efficiency and product quality.

In addition, titanium dioxide (TiO₂) also has other special functions in rubber products. In terms of improving water resistance, for products such as rubber seals and rubber hoses that come into contact with water, the addition of titanium dioxide can enhance their water resistance. Relevant studies have shown that, in room-temperature vulcanized silicone rubber (RTV) treated with nitrogen dioxide aging, when the composite ratio of surface-functionalized titanium dioxide nanosheets (f-TNS) is 0.3 wt.%, the composite sample exhibits the lowest water permeability, the best resistance to nitrogen dioxide corrosion, increased impedance modulus, and reduced porosity, fully demonstrating the improvement in water resistance. In addition, by inhibiting UV-induced oxidation reactions, titanium dioxide can further delay the deterioration of rubber product performance. This effect complements its anti-aging function, jointly ensuring the long-term performance stability of rubber products, which is especially significant for rubber products used outdoors.