Growth in Asia is slowing, moving into the lower single digits in some cases. In China's case economic growth of 7 percent is targeted, meaning sellers of plastic materials in the market either have to temper their expectations or turn to innovation in order to develop new applications with customers. Case-in-point: DuPont has developed an ionomer film technology based on its Surlyn polymer to protect fiber-reinforced plastic (FRP) pipes from chemical attack in reverse osmosis water treatment.
|Geomembranes (above) and water treatment pipe linings (below) are two applications where well-established DuPont products are getting new leases of life.|
"The ionomer film improves the productivity of water treatment by reducing the frequency of cleaning and replacing water treatment pipes," says Roger Kant, Marketing Director, DuPont Packaging & Industrial Polymers - Asia Pacific. "The technology was developed at our Shanghai R&D facility, who identified the opportunity," adds Kant. "It also widens the application area so that more seriously polluted liquids are treated."
In the pipe production process, a Surlyn film is first wrapped around the mandrel and epoxy resin-impregnated fiberglass is then wound on top of the film and cured.
Surlyn is also being used as a cap layer in wood plastic composites (WPCs) to protect them and deliver a more wood-like appearance, less fading over time, increased scratch and stain resistance, and reduced mold buildup. "It allows the processor to concentrate the additives and colorants in the outside layer of the wood composite," says Kant. "The technology has recently been adopted by an Asian processor following cases in North America."
Another new application where a DuPont product is finding application is geomembranes made in South Korea, where the company's Elvaloy polymeric plasticizer contributes to extended lifetime in the field. "Geomembranes with conventional plasticizers normally last one year, after which they are prone to failure due to plasticizer migration resulting in membrane brittleness," says H.S. Lee, Industrial Market Manager, DuPont Packaging & Industrial Polymers, Asia Pacific. "Adding a small amount of Elvaloy to the existing formulation, however, extends lifetime to 3-4 years. Adding even more can extend this further to 10 years."
Geomembranes requirements include resistance to long-term UV exposure, low temperature flexibility, resistance to contaminants such as oils and fats and chemicals, and heat weldability to ease assembly and installation. The non-migratory solid plasticizer reportedly helps meet these requirements.
In addition to its role as a plasticizer, Elvaloy also functions as a compatibilizer and coupler in a cable jacket application that delivers cold temperature flexibility retention and durability. "These properties are particularly important in applications such as elevator cables in countries with cold climates," says Lee. "The additive realizes low smoke generation and can accept high filler (flame retardant) loadings."
Another application of Elvaloy terpolymers is in impact modification for rigid PVC. "They as impact modifiers as well as improving production yield, i.e., functioning as a processing aid," says Kant. "We are looking at automotive interior applications which require low-temperature properties," he adds.
While Elvaloy is not a new technology, it is coming under renewed focus due to concerns regulatory concerns. "There is a new emphasis on solid plasticizers rather than liquid as the former are non-migratory," says Kant.