Color can make or break commercial plastics. And commercial or extruded plastics in the wrong color will likely require a new manufacturing run to produce the correct product, increasing waste and energy consumption.
Extruded plastics - the kind used for objects with a specific shape, like shampoo bottles or car interiors - frequently have to be a specific color to be consistent across the same product or brand. However, extruded plastics are made at temperatures up to 752°F (400°C) and pressure up to 2,000 psi - conditions that would break conventional instruments for measuring the color.
As a result, manufacturers have to wait until the plastic is made to check the color. If it does not meet specifications, they must recycle it into a new batch of plastic, consuming extra energy and creating extra greenhouse gases.
Guided Wave Inc., Rancho Cordova, Calif., has developed a probe to withstand the heat and pressure of the extrusion process. The company won a $25,000 award in May from the U.S. Department of Energy’s Industrial Energy Efficiency Grand Challenge, which funds projects that reduce greenhouse gas emissions and energy use in American industry.
“This has been sitting in the background for awhile,” says Susan Foulk, Guided Wave’s vice president of operations. “It was just a perfect match, because we knew the energy savings from reducing the waste could be substantial.”
Guided Wave also is spending $75,000 more to make a spectrometer used in conjunction with the probe to analyze the colors the probe detects. Both items will be made at the company’s headquarters and should be on the market within two years. When the probe and spectrometer are finished, the company plans to partner with a plastics manufacturer to test the equipment under process conditions.
If successful, the equipment can be used throughout manufacturing, in any application where color is important and conditions are harsh. Potential applications include the manufacture of ink, detergents and other liquids as well as polymers, says Terry Todd, corporate fellow at Guided Wave.
Because of differences in energy use and waste, the manufacturer says it cannot predict actual energy and financial savings for any one customer, but the savings should be substantial enough to matter to those customers that manufacture plastics such as soft drink and shampoo bottles.
Wasting batches “probably doesn’t happen more than 10 percent of the time - because if it happened more, they’d go out of business,” Todd says. Yet “it’s expensive enough that it can pay for the instrumentation as long as the instrumentation doesn't cost a fortune.”
Those concerns about cost vs. benefit are one reason why the instrument is not already on the market, she says. Others include the engineering challenges created by the very high temperatures, high pressure and low light conditions.
Technology has only recently been able to address these issues in a cost-effective way, Todd says. “The DOE grant will help us bring down the development cost, which will help us bring down the selling price.”