Ford eyeing low carbon-footprint glass spheres as replacement for talc

The carmaker plans to collaborate with RockTron to use that company's technology to recycle coal-fired power station waste into glass spheres that can be used to fill plastic compounds. The fillers have the potential to replace talc or established glass sphere fillers, and in the process lower a compound's density as well as improve its scratch resistance.

RockTron (Bristol, England) offers a technology that can be used to recycle the fly ash waste generated in coal-fired power stations, to functional fillers that can be used to substitute traditional fillers in plastics, and also in rubber, coatings, thermoset plastics and cement. The work with Ford Motor Company and plastics suppliers and compounders will focus on developing new compounds incorporating RockTron's recycled, functional fillers for interior, exterior and underhood applications—substituting, partially substituting, and combining RockTron's products with other fillers to produce a range of hybrid compounds. The spherical shape of RockTron's solid alumino-silicate glass MinTron solid alumino-silicate (glass) spheres are said by RockTron to offer advantages in dispersion compared with other irregular shaped fillers. In addition, the hardness of the glass spheres (5-6 on the Mohs scale) gives high scratch resistance. The company also offers hollow alumino-silicate spheres, marketed as CenTron. 

For example, on scratch test plaques where a PP co-polymer containing 15% talc was compared to an identical co-polymer with 15% MinTron replacing the talc, scratch resistance was higher and a 50% reduction in emissions (the "new car smell") was measured. MinTron's density of about 2.2 is 20% less dense than talc too.

In an interview during last autumn's K show in Germany, RockTron's director of advanced products, Godfrey Short, offered us details of his company's MinTron 7 eco-filler. MinTron 7 comprises solid alumino-silicate glass spheres derived from fly ash. The 7-µm particles are grey but Short noted that 80% of plastic automotive components are black, so the drab color need not be a hindrance.

"MinTron 7 does not compete with low-cost calcium carbonate filler," Short told Stephen Moore in the interview. "We aim to compete with synthetic glass spheres."  These manufactured glass spheres can cost up to $2000 per tonne but Short believes that cost-competitive MinTron 7 may expand utilization of glass spheres beyond niche applications. Major suppliers of glass spheres include 3M and Potters Industries.

Target auto applications for RockTron's products include nylon engine covers. Besides reinforcing, the glass spheres also prevent warping in thick sections and ensure controlled dimensions.

RockTron says its recyclined fillers also are beginning to tun heads in non-automotive applications, including in molded plastic roof tiles. Another potential application is wire and cable. Short says that the glass spheres form a non-hygroscopic char upon combustion and can assist with the flame retardation.

The company claims interest in its products and technology, which it licenses, is global, with the company opening RockTron Asia in October 2010 two years ahead of schedule. It also has developed a new partnership licensing business model, which allows RockTron and its partners to develop into multiple international markets simultaneously, without compromising existing agreements or future opportunities. The first industrial plant licensed to use RockTron's technology is at Fiddler's Ferry, Cheshire, England, which is in full operation and capable of recycling up to 800,000 tonnes of fly ash per annum. —PlasticsToday Staff