Dow breakthrough enables better paint with less TiO2
Evoque Pre-Composite Polymer Technology increases TiO2 efficiency, improves hiding efficiency, enables up to 20% less TiO2 and enhances barrier properties such as stain resistance and removal.
Published April 5, 2011
Dow Coating Materials (DCM), a global business unit of The Dow Chemical Company, has launched Evoque Pre-Composite Polymer Technology. The company says it is a revolutionary development for paints and coatings, hoping to change the way formulators think about hiding and the use of titanium dioxide (TiO2).
“Hiding is at the heart of every paint formulation and without TiO2, we would not have paint as we know it today,” said Joan Schuller, general manager, North America, Dow Coating Materials. “But TiO2 has been stretched to its limits, both in terms of hiding efficiency and supply.”
Evoque Pre-Composite Polymer Technology improves the particle distribution and light scattering efficiency of TiO2, facilitating improvements in hiding efficiency and allowing for up to 20 percent less TiO2 used in the formulation, the company said. Additional benefits include improved barrier properties such as stain and corrosion resistance.
“This is game-changing technology that will make paint formulators rethink hiding,” said Schuller.
Depending on their formulation goals, paint manufacturers can use Evoque Pre-Composite Polymer Technology to reduce TiO2 content or improve hiding while they improve paint performance. The technology may also help formulators reduce the carbon footprint of their end products by reducing the energy footprint that comes from mining, processing and transporting TiO2 to their formulation plants. DCM is conducting a life cycle analysis, which will be verified by a third party, to quantify the full spectrum of sustainability advantages that may result from using Evoque Pre-Composite Polymer Technology.
“Evoque Pre-Composite Polymer Technology gives formulators new options and more flexibility when tailoring paint performance to meet the demands of specific markets and applications,” said S. Ashok Kalyana, North America strategic marketing manager, Dow Coating Materials. “For example, formulators can use Evoque Pre-Composite Polymer Technology to increase the hiding performance and market value of premium paints. They can also use Evoque Pre-Composite Polymer Technology to maintain equal hiding and improve paint performance while reducing TiO2 content and raw material cost. It truly provides flexibility to the formulators in designing performance in their paint lines.”
Evoque Pre-Composite Polymer Technology is compatible with Ropaque Opaque Polymers, which were introduced by DCM 30 years ago. Evoque Pre-Composite Polymer Technology works in tandem with Ropaque Opaque Polymers to further increase hiding efficiency and reduce TiO2.
Titanium dioxide, or TiO2, is the world’s most widely used white pigment due to its brightness and high refractive index. In typical paint formulations, however, the efficiency of TiO2 is limited by uneven particle distribution, Dow said. This effect can be due to poor dispersion and crowding. Adding more TiO2 helps, but only up to a point before formulators reach a level of diminishing hiding returns.
“We decided to take a different approach,” said Dave Fasano, research scientist. “Instead of using more TiO2 to improve hiding, we looked at ways to make it more efficient.”
Evoque Pre-Composite Polymers surround and attach to the surface of TiO2 particles.
As the two materials come together, they form a composite that makes TiO2 better dispersed and more resistant to crowding.
“In effect, we’re making every particle of TiO2 work smarter,” said Fasano. “That opens up a whole new range of options that formulators do not have with TiO2 alone. Depending on the formulation, Evoque Pre-Composite Polymer Technology can also impart improved stain resistance and removal, as well as primer-like properties such as tannin, marker stain blocking or corrosion resistance.”
Evoque Pre-Composite Polymer Technology is acrylic based and early testing indicates excellent durability properties for this platform. These properties are further enhanced by removal of some of the TiO2, which participates in some of the photochemical processes that degrade films. Samples of paint formulated using Evoque Pre-Composite Polymer Technology are undergoing exterior exposure testing, and they are performing well, the company said. Dow anticipates offering Evoque Pre-Composite Polymer Technology for exterior waterborne paints by 2012.
Dow expects full commercialization of Evoque Pre-Composite Polymer Technology during the third quarter of 2011, with rapid expansion of the line in 2012.
Visit DCM on the web to learn more at www.dow.com/hiding.
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