Sharp rises in titanium dioxide prices and their impact on paint formulations were a major issue at the recent European Coatings Show (ECS) at Nuremberg, Germany, with materials suppliers presenting a range of options for helping coatings companies to cut the TiO2 content of their products.The big challenge facing paint producers is how to decrease TiO2 in their formulations without sacrificing quality.
However TiO2 prices have been going up so relentlessly and look likely to go up even higher that producers are having to consider trade-offs between cutting TiO2 quantities in formulations and marginal drops in opacity.
“The TiO2 shortages have reached ridiculous levels,” said one materials supplier at the ECS. “Paint producers are struggling to get supplies. They are putting as much as possible of what they can get into stocks because of uncertainties of availability of TiO2 later in the year.”
Europe, where annual TiO2 demand is approximately 1.5 million tons or about a third of the world’s total, is particularly vulnerable to a tight supply/demand balance of the pigment. This is partly due to plant closures in the region during the recession and a predominance of aged capacity, a high proportion of which uses the costly sulphate process. DuPont, whose extensive distribution network in Europe makes it one of the region’s leading suppliers, imports all of its TiO2 into the region, mainly from North America.
TiO2 prices have gone up by roughly 50 percent since early 2008 and by 25-30 percent since late 2009. The price per ton was predicted by analysts to exceed €3,000 ($4,200) per ton by the end of 2011 but this should now happen in the first half of the year.
During the second quarter TiO2 producers were pressing for 5-10 percent rises after pushing through similar increases earlier in the year.
There seems to be little hope of new capacity being built in Europe over the next few years. The leading producers with European plants—Huntsman Corp., Kronos and Cristal—have said they have no plans for major expansions. In fact Kronos, one of the region’s biggest producers with five plants, has insisted that TiO2 prices have not reached a level which would justify investment in new facilities.
DuPont has postponed the start-up date of a planned 200,000 ton-a-year unit in China costing $1 billion to 2015. After the project was announced in 2005 it was originally going to be opened in 2009.
Chinese producers are thought to have brought on stream in 2010 capacity close to 500,000 tons a year without which the pressure on supplies in the rest of the world would have been even worse.
In the last two years, however, total imports into China of TiO2 feedstocks—ilemnite, rutile and titanium—have at least doubled, which has contributed to the stress on supplies throughout the global supply chain for the pigment.
TiO2 producers at the ECS were claiming that uncertainties about the availability of feedstocks supplies were an obstacle to investment decisions in new capacity in Europe.
Short-term supply agreements and prices have now been extended to feedstocks as well as TiO2 itself. Feedstock producers will only commit to delivery deals covering 12 months rather than three to five years as was the custom previously, while agreements on prices cover only a few months.
The last new TiO2 plant to be built in either Europe or North America was around 20 years ago. It will probably be at least a minimum of four to five years before another one is constructed in either region. DuPont has said it is planning a brownfield expansion in the U.S. over the next few years while other capacity increases will have to come from debottlenecking
With the prospect of a lengthy period of high TiO2 prices, an incentive for coatings materials suppliers to offer ways of reducing the pigment’s content in formulations is that they will be applied permanently rather than temporarily.
“Once coatings manufacturers have worked out formulations with lower TiO2 contents they will stick with them,” said Frank Huskey, technical service manager at KaMin, a performance minerals producer in Macon, Georgia. “The rise in TiO2 prices and the knowledge that the increases will continue has made coatings companies look much more carefully at the efficiency of TiO2 in their formulations. Previously when TiO2 prices were at a lower level there was no motivation to do that.”
The main means of decreasing TiO2 content is the improvement of spacing and dispersion of the pigment’s particles so that they operate more effectively in the paint.
“On average only approximately 75 percent of TiO2 in a formulation is being used effectively,” said Martin Fisher, European specialty sales manager at the Finland-based engineered materials business of Huber Group of Germany. “The remaining 25 percent is wasted because the particles are too crowded and get in each other’s way. To get the best performance out of TiO2 particles they need to be spaced at the right distance from each other.”
Huber provides amorphous sodium aluminosilicate particles for matt coatings with a uniform size of around 0.3 microns to act as ‘spacers’ for the separation of TiO2 particles. They also have a light scattering effect to provide opacity.
KaMin supplies ultrafine clay particles of 0.2 microns in size as spacers to help the dispersion of TiO2 within gloss paints. The company says that with the aid of its micro particles the TiO2 content of formulations can be reduced by as much as 30 percent.
While mineral particles act independently of TiO2 particles to keep the two substances apart from each other, polymers have been developed to perform a similar function but by binding themselves to the titanium dioxide.
Dow Chemicals at the ECS launched a polymer, which attaches itself to TiO2 particles to form a composite. This improves the dispersion of TiO2 and helps prevent crowding so that it has greater light scattering efficiency. The company says it can reduce TiO2 in a formulation by up to 20 percent while retaining similar opacity or hiding levels.
“Instead of using more TiO2 to improve hiding, we looked at ways to make it more efficient,” said Dave Fasano, a Dow research scientist. “In effect we’re making every particle of TiO2 work smarter. That opens up a whole new range of options that formulators do not have with TiO2 alone.”
In fact highly priced TiO2 could bolster R&D in an area of research in not only the particle sizes of the pigments but also their shapes and surface textures and interaction with filler materials with the aim of using less of the chemical but with the same effect.