ADDITIVES | RECYCLING
Below: Struktol’s TR219 has been shown to be an effective compatibiliser for PET recyclates with other polymeric contaminants
products for these applications. “RP 23 is our newest viscosity modifier for PP and can be used at low loading levels to give significantly higher MFR,” Fulmer says. “The product is easy to handle and feed and provides very consistent viscosity modifi- cation. RP 53 is a key odour modification additive. It is a combination odour neutraliser and absorber and can remove odours caused by a variety of chemical species. Low loading levels of less than 1% can provide significant reductions of odour. TR 052 is an important homogenising additive and can be used in commodity and engineered polymer systems. This additive provides for improved melt mixing in any type of processing equipment often leading to higher physical proper- ties and improved processability.” Other Struktol additives include TR 229, which acts as a compatibiliser and lubricant for use in polycarbonate (PC) and PC/acrylonitrile-butadiene- styrene (ABS) blends as well as nylon 6 and 6,6 compounds. It can be used in virgin and recycled blends and is FDA-approved. Struktol also offers TR 219. Developed originally as a compatbiliser and lubricant for use in virgin and recycled nylon 6 and 6,6 compounds, it is has also been found to be effective in polyester (PET and PBT) compounds, especially in recycled or recyclate-containing applications or in cases where the polyester compound is contaminated with other plastics. RP 38 is designed to provide viscosity modifica- tion and lubrication in recycled PP compounds and resins that contain moderate to high levels of polyethylene contamination. It also incorporates some odour control performance. The company says that when used at loading levels as low as 0.2%, it results in increased melt flow and allows for significant improvement in mould filling and release. Processors using RP 38 are said to be able to develop compounds from regrind or recycled feed streams without sacrificing key properties or performance. The RP 38 products can also be tailored to individual compounder’s requirements.
Viscosity modification RP 38 employs vis-breaking technology. “RP 38 is a viscosity modification additive for PP that is de- signed to work in recycled PP streams that contain high levels of PE contamination,” Fulmer says. “This product reduces the molecular weight and viscosity of the PP portion of the recycled stream while at the same time protecting the PE portion from crosslink- ing, which is a typical occurrence when using other peroxide-based PP viscosity modifiers. A current customer kept having to add more and more of a competitive product trying to increase the MFR of the recycled PP stream but saw no change in the MFR due to the competing crosslinking of the PE portion of his base stream. Switching to RP 38 allowed the use of lower loading levels of viscosity modifier to achieve the target MFR.” Developed as a processing aid, TR 251 is a
combination product that includes surfactant and lubricant technology. Struktol says it has proven to be effective in improving mould flow of recycled compounds without significantly changing the melt flow rate, allowing processors to realise improved flow and filling in thin wall products along with enhanced release characteristics. It does this without vis-breaking, so compounds produced using it typically display more controlled physical properties. Fulmer says the company sees considerable
opportunity in the recycling sector. “Struktol will continue to focus on this growing market and provide additive solutions to processing problems based on feedback from the industry,” he says. “We will continue to develop new products providing bet- ter, more efficient viscosity modification as this is an important, growing need in the market. We are also working on products to improve specific physical properties in several recycled polymer applications.”
Sustainability drivers Lars Öhrn, Chief Marketing Officer of Nexam Chemical agrees that there is increasing demand and interest for recycled polymers throughout the value chain for many applications. “Performance from recycled polymers in terms of processability and in final applications is improving and the time when the driver to use recycled material was only cost is over,” he says. “Properties are now increas- ingly expected to be equivalent to virgin material. The driver is sustainability.” Öhrn highlights a number of current issues in
the recycled compound industry. These include process stability and increased melt strength, as well as the ability to run long process times without stopping for cleaning or failures. Performance of recycled plastics in different applications is also an
56 COMPOUNDING WORLD | September 2018
www.compoundingworld.com
PHOTO: STRUKTOL
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