Under weather: super durable TiO2 for plastic application

RD Titan Group Innovative TiO2 together with Artikol, Chemours, TiPMC Consulting, Venator, TDMA, FP-Pigments, Ineos, Tronox just published an article in the October 2019 edition of Compounding World magazine on the topic of the analysing the titanium dioxide market.

RD Titan Group Innovative TiO2 shares new development and claims to be tackling the challenge of weathering performance. According to Andriy Gonchar, Director at RD Titan Group Innovative TiO2, typically, TiO2 grades for plastics are characterised by high hydrophobicity, which ensures good mixing during compounding and easy distribution in the polymer matrix. However, not every grade of hydrophobic TiO2 is suitable for production of plastics that are exposed to external weather conditions (UV radiation, humidity).

TiO2 is a photocatalyst that absorbs UV radiation, he explains. When that UV absorption takes place in the presence of moisture a cycle of chemical reactions is initiated leading to the formation of extremely reactive free radicals. These can react with the molecules of the polymer matrix and cause its destruction. This process releases pigment particles enclosed in the polymer matrix, leading to chalking and loss of surface gloss.

To avoid – or to significantly slow – this phenomenon, TiO2 manufacturers have developed special grades with reduced TiO2 photocatalytic activity. Gonchar says this is typically achieved by introducing special dopants to decrease photocatalytic activity of the TiO2 lattice or by applying inorganic surface treatments such as silicon oxide or zirconium compounds. The former are intended to act as a barrier on the TiO2 surface while the latter capture the free radicals formed.

Gonchar says both TiO2 lattice doping and surface treatment involve complicated operations with a lot of critical nuances to be taken into account. Therefore, he advises that users take care to evaluate the quality of offered products by conducting their own weathering tests – either accelerated or in real outdoor conditions. RD Titan Group Innovative TiO2 has developed its own technology for production of super-durable TiO2. Its RP-72 grade production technology makes it possible to produce titanium dioxide with superior weather durability, according to Gonchar. It involves the combination of three technologies: TiO2 particles are encapsulated in a dense silicon oxide; the crystal lattice is doped using a specially developed technology to reduce photochemical activity; and a “free radical scavenger mechanism” is applied to neutralise any free radicals that can form.

More recently, RD Titan Group Innovative TiO2 has developed an even more durable grade. RP-8829 is said to be exhibit twice the durability of RP-72 (determined as 5% acid solubility for RP-8829 versus 10% for RP-72).

There is a full article Inside the TiO2 market:

The October 2019 edition of Compounding World is now available for viewing. Just click here to see the magazine in full,

completely free of charge.