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Dow Targets High Pigment Prices With Resins

Today, a story I wrote on the on fortunes of the TiO2 market appears in the current edition of C&EN. TiO2 is the white pigment that gives paint its hiding power. If you ever labored applying coat after coat of white paint on a wall in vain trying to cover up a red finish that refuses to die with dignity, then the manufacturer of the paint you have chosen probably skimped on the TiO2. (It isn’t your fault. Actually, it is, you bought cheap paint.) I can’t think of a single commodity that is more important to the paint industry than TiO2.

And the paint industry has recently been paying dearly for TiO2. Since the 1990s, the TiO2 industry has been plagued by too much manufacturing capacity. That changed when the Great Recession forced the sector to shut down excess output. With the recovery, the TiO2 industry is now seeing the greatest profitability in about 20 years.

For the paint makers that consume the white pigment, runaway TiO2 prices have been painful. These companies are trying to mix in as little of it in their formulations as they can get away with. PPG has one of the more militant stances on this issue in the paint sector. The company wants to reduce TiO2 consumption by 10% by the end of next year. The company has gotten off to a good start, eliminating 2% by the end of the last quarter.

There is a potential market here for chemical companies that I couldn’t really get into in the article in print. Last year, Dow Chemical launched its Evoque pre-composite polymer, meant to address the problem of TiO2 crowding in latex paints. TiO2 crowding is what it sounds like it is, but there is even more to it than that.

David Fasano, a research scientist at Dow, explains that at very high loadings of TiO2 used in white and architectural latex paint—about 20%–TiO2 begins to interfere with its own ability to scatter light. This is because the TiO2 particle has a sphere of influence, called a scattering zone, that is twice the diameter of the TiO2 particle itself. As the particles come closer together, these zones overlap, diminishing the effectiveness of each other. (To understand this, I imagine an overhead projection of two dots on a screen. As the projector goes out of focus, halos form around the dots and expand until they overlap.)

Evoque, an acrylic latex film-forming resin, binds to the TiO2 particles and holds them apart so they don’t get close enough to interfere with each other. Evoque can reduce the paint loading in white and pastel architectural paints by as much as 20%.

Along with Evoque, Dow has been promoting another resin that has been in its stable for about 30 years: Ropaque. It isn’t meant to extend the use of TiO2, it is styrene-based resin that acts like a pigment itself. When Ropague forms a film, it captures little pockets of air that scatter light. This is the same effect that makes polystyrene foam, clouds, or bubble baths appear white.

Dow is quick to point out that it isn’t trying to exploit the high TiO2 prices. Evoque has been under development for a more than 5 years, before the TiO2 prices took off. However, Ashok Kalyana, architectural marketing director for Dow Coating Materials, admits that the product was launched at a fortuitous time. “This wasn’t invented just to take advantage of the situation,” he says. “But certainly the tightness in the TiO2 market has helped us accelerate our plans of introduction.”

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