3.30 TITANIUM DIOXIDE

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1 TITANIUM DIOXIDE Technology Prospects Addressable market size 5 Competitive landscape 3 IP landscape 4 Commercial prospects 4 Technology drawbacks 3 Total score (out of max. 25): Properties Nanoparticle titanium dioxide dates back to the late 1970 s when the first patent on its preparation was issued in Japan. In terms of production, it is in principle possible to obtain nanoparticle TiO2 by simple milling of the pigmentary TiO2 to a finer particle. However, the properties of the fine powders in terms of purity, particle size distribution and particle shape are unsatisfactory. Several wet chemical processes were developed during the 1980 s by TiO2 pigment manufacturers such as Ishihara, Tioxide and Kemira. The first part of the process, the production of the nanoparticles base material uses after-washes titanium hydroxylate as the raw material. After subsequent process steps involving the decomposition of the hydroxylate crystal structure and the reprecipitation of the TiO2, the product is calcined to obtain oval-shaped particles with a desired primary crystal size and narrow size distribution. The base crystals are coated in the aftertreatment unit according to the requirements of the end-use. One of the primary tasks of the after treatment is to ensure good dispersability of extremely fine particles in the final application. TiO2 nanoparticles are also routinely produced by the gas-toparticle conversion in flame reactors because this method provides good control of particle size, particle crystal structure and purity. Titanium Dioxide and Nano Titanium Dioxide are totally two different materials. Titanium Dioxide is mainly used as white pigment for paint and cosmetic industry and most in micron particle size. Nanoscale titanium dioxide (nano-tio2) has a much greater surface area of a given mass or volume of nanoparticles compared to an equivalent mass or volume of conventional TiO2 particles, affording greater potential for properties such as catalytic activity and UV absorption at certain wavelengths. 92 Bulk TiO2 primary size is best if greater than 250nm. It possesses excellent light scattering properties, is optimized to scatter visible light and absorbs UV light. Nano TiO2 primary particle

2 182 size is 100nm or less and is optimized to absorb UV light (sunscreens and protection) for its high surface area in catalysis and its selective wavelength scattering for color effects. Based on the light scattering property described earlier, nanoparticle titanium dioxide can be used to impart excellent UV protection. Compared to the available UV absorbers, ultrafine nano- TiO2 possesses effective UV filter properties over the entire ultraviolet spectrum (UVC + UVB + AVA). For example, it is gaining a wide acceptance for use in sun creams. Nanoparticle TiO2, apart from its effective attenuating characteristics is extremely inert and therefore, safe to use next to the skin. Nanoparticle TiO2 can also be used in clear plastic films to provide UV protection to foodstuffs. Table 127: Optical Behavior of Pigmentary and Nanoparticle TiO2 Under Visible and UV Light Particle Size Wavelength < 400 Wavelength >400 Pigmentary TiO2 Semiconductor absorption Scattering and reflection (Mie scattering) Nanoparticle TiO2 Semiconductor absorption Scattering and reflection (Rayleigh s theory) Transmission of light. Particle diameter <<wavelength These properties have led to the exploitation of nano-tio2 for a wide variety of applications, including self-cleaning surface coatings, UV-resistant coatings and paints, solar cells, disinfectant sprays, and water treatment agents and topical sunscreens. Commercially available brands of nano-tio2 vary in particle size, surface area, purity (e.g., due to doping, coating, or quality control), surface characteristics, crystalline form, chemical reactivity, and other properties. Nano- TiO2 is available in pure anatase, pure rutile, and mixtures of anatase and rutile. In general, anatase nano-tio2 is more photocatalytic than the rutile form, and nanoscale rutile is less photoreactive than either anatase and rutile mixtures or anatase alone. 93 However, a mixture of 79% anatase and 21% rutile nano- TiO2 (P25) was found to be more photocatalytic than 100% anatase nano-tio2 in some instances 94, but less effective in others. 95 Such contrasts point to the role of other factors in accounting for the behavior and effects of nano- TiO2. For example, surface treatment of nano-tio2 can change nano-tio2 activity, including photoreactivity. Aeroxide T805, which is nano-tio2 that has been treated with trialkoxygoctyl silane on the surface, has very low surface reactivity. Similarly, surface coatings of silicone and other compounds are used to decrease nano-tio2 photoreactivity so that nano-tio2 can be used to protect human skin, plastic, and other objects from UV radiation. 96

3 183 Table 128: Nanoparticle TiO2 market applications Market Ceramics Cleaning and sanitary Applications Nanoparticle TiO2 is used in multilayer ceramic capacitors (MLCCs). Nanoparticle titanium oxide is used in the production of barium titanate (BaTiO3), which is then used as raw material for dielectric*, one of the basic components of MLCCs. Nano-TiO2 photocatalyst nanocoatings that destroy viruses, bacteria, odor 97 Clothing Anti-bacterial textiles 98 Construction & exterior protection Energy Environmental Personal care Paper Plastics Self-cleaning, air-cleaning and antibacterial effects construction materials (Paints and coatings on glass). 99 When exposed to solar radiation Nano-TiO2 acts as catalyst for photodecomposition of pollutant molecules adsorbed on its surface and transformation into non-toxic compounds. Lacquers and paints that resist UV degradation. In such applications, the high RI of nano-tio2 is needed but the photocatalytic activity of these nanoparticles is undesirable and must be suppressed. Photocatalytic concrete with de-polluting and de-soiling properties 100 Thin films of nanocrystalline titanium dioxide are used in solar cells Titanium dioxide as chemical catalysis applications such as e.g. the photocatalytic purification of water and air leading to a destruction of organic pollutants. Titanium dioxide nanoparticles are effective against water-borne microbes, including bacterial spores and chlorine resistant organisms. They are also effective at degrading organic pollutants (such as herbicides and pesticides). 101 Titanium dioxide nanoparticles have been doped with boron to harness visible light and therefore be effective remediators of indoor air Sunscreens: Titanium dioxide in its nano-form has improved UV attenuation properties, especially with regard to light scattering. The properties of nano-tio2 ensure that formulations are lighter and can be spread more evenly on the skin, which ensures better UV protection 102 Used in the pulp and/or the coating of high-quality papers and boards Anti-bacterial paper and tissue UV-resistant plastics additive Anti-bacterial and oxygen barrier food packaging films

4 Commercialization timeline Table 129: Commercialization timeline for titanium dioxide nanomaterials, Applications Photovoltaic thin films Printing inks Photocatalytic pigments and coatings UV resistant paints Heat stablizier for silicone Additive for toner Catalyst carrier UV filters in textiles Coatings and paints for sanitization and elimination of MRSA UV Protective Clear Plastic Films in food packaging Oxygen resistant food packaging Super hydrophobic paper Filtration membranes Anti-bacterial tissue products Anti-bacterial paper products Photocatalytic anti-bacterial nanocoatings Anti-bacterial wipes Multilayer ceramic capacitor additives Nanocomposite implants Self-cleaning clothing and textiles Self-cleaning surfaces for buildings and structures (Anti-soiling and anti-fungal growth and VOC/NOx reduction

5 185 (emissions) Photocatalytic cement additives Dye-sensitized solar cells Nano-TiO2- coated polymer electrolyte membranes for direct methanol fuel cell Self-cleaning solar cell coatings Wastewater and air pollutant cleanup Automotive paint additives High UV, transparent sunscreens UV resistant cosmetics UV filter in plastics Stage of commercialization (SoC) Key Basic research Applied research Prototype Commercialized Mass market

6 Demand by market Figure 55: Demand for titanium dioxide nanoparticles, by applications, percentage, 2012 Cosmetics 53% Food 9% Paints and coatings 22% Plastics 4% Academic/ research centres 2% Energy 6% Environment 4% Source: Future Markets, Inc Production volumes, tons Figure 56: Demand for titanium dioxide nanoparticles, , tons, conservative and optimistic estimates TONS/YEAR Conservative Optimistic