What is rutile titanium dioxide?
Titanium dioxide (TiO₂) occurs in two commercially relevant crystal forms: rutile and anatase. Rutile is the denser, more stable form, and it scatters light more efficiently and weathers far better than anatase. That is why virtually all pigment used in durable coatings and in plastics is rutile, while anatase is reserved for niche uses where its softer, more photoactive surface is acceptable.
Commercial rutile pigment is not bare TiO₂. Each grade carries an inorganic coating — typically alumina, often with zirconia — and an organic treatment. Those layers decide how durable the pigment is outdoors and how easily it disperses in your system, so two grades with identical TiO₂ purity can behave very differently on the line.
Why formulators use rutile TiO₂
High refractive index
Rutile is the densest, most thermodynamically stable crystal form of titanium dioxide. Its high refractive index scatters visible light very efficiently, which is what delivers opacity and hiding power at low loadings.
Whiteness and bluish undertone
Controlled particle size and distribution give high lightness with a bluish undertone, the tone most paint and plastics formulators specify for clean, bright whites and accurate tinting.
UV durability
Inorganic coatings of alumina and zirconia reduce the photocatalytic activity of the pigment surface, protecting the binder or polymer from chalking and yellowing in exterior exposure.
Dispersibility
Organic surface treatment lets the pigment wet out and deagglomerate quickly, shortening grind times in coatings and improving filter pressure value and throughput in masterbatch.
Heat stability
Plastics grades are built to resist yellowing at processing temperatures, with grades in this range specified for use up to 300 °C.
Chemical inertness
TiO₂ is insoluble, non-reactive with common binders and polymers, and stable across the pH range encountered in waterborne and solventborne systems.
Sulfate process vs chloride process
Rutile pigment is manufactured by one of two routes. The sulfate process digests ilmenite concentrate in sulfuric acid; the chloride process converts a higher-grade titanium feedstock through titanium tetrachloride. Both produce rutile pigment, but they land in different places commercially.
| Sulfate process | Chloride process | |
|---|---|---|
| Feedstock | Ilmenite concentrate | Higher-grade titanium feedstock |
| Typical undertone | Bright white, bluish undertone | Bright white, bluish undertone |
| Particle-size control | Good — suits general-purpose coatings, inks and paper | Tighter — suits high-gloss, high-durability and masterbatch work |
| Common positioning | Cost-efficient general-purpose and decorative systems | Premium durability, gloss and tinting strength |
In practice the process is a starting filter, not a verdict. Compare the published specifications and the surface treatment before you decide.
How to read a rutile TiO₂ specification
- TiO₂ content
- The pigment fraction of the powder, typically ≥ 90–93 %. Higher content means more of what you pay for is active pigment.
- Rutile content
- The share of the TiO₂ present in rutile crystal form, typically ≥ 97 %. Anything below that dilutes durability and opacity.
- Particle size
- Around 0.2–0.4 µm. Light scattering peaks in this window, so particle size drives both opacity and undertone.
- Oil absorption
- How much binder the pigment demands (g/100 g). Lower values allow higher pigment loading without pushing up viscosity.
- pH value
- Usually 6.5–8.5. It affects stability in waterborne formulations and compatibility with other additives.
- Density
- Around 4.0–4.3 g/cm³, used for volume-solids and cost-per-litre calculations.
- CBU (colour black undertone)
- A tinting-strength measure used for plastics grades — a higher figure means more colouring power per kilo.
- Surface treatment
- Inorganic coatings (alumina, zirconia) for durability, plus an organic treatment for dispersion. This is often the real difference between two grades of similar purity.
Every OxiWhite Global grade publishes these figures on its own page, with the full manufacturer datasheet available to download as a PDF.
Rutile TiO₂ in paints and coatings
In coatings, rutile TiO₂ provides hiding power, whiteness, gloss and exterior durability across interior and exterior architectural paint, emulsion paint, powder and coil coatings, automotive OEM and refinish, printing inks and paper. Grades aimed at this sector prioritise gloss development, scattering power and resistance to chalking.
- R-5566 — sulfate process
- R-244 — sulfate process
- R-298 — sulfate process
- CR-350 — chloride process
- TYR-588 — chloride process
Rutile TiO₂ in plastics and masterbatch
In polymers the priorities shift. High-concentration masterbatch, film blowing, fibre and spinning and engineering plastics such as PVC, PE, PP and ABS demand tight particle-size control, resistance to yellowing at processing temperature, a good filter pressure value and high tinting strength, so that the pigment runs cleanly through screens and dies without slowing the line.
Choosing the right grade
Start from your application and process, then narrow by specification: opacity and gloss for coatings, dispersibility and heat stability for plastics. Storage matters too — rutile pigment should be kept away from direct contact with moisture, and is normally supplied in 25 kg paper bags or 500–1000 kg jumbo bags.