Additives: Novel Process Aid for rPET and PET Preforms
A newly patented, APR accredited liquid dispersion process aid for rPET producers and converters reportedly allows for greater recycled content in PET bottles to reduce carbon emissions and support sustainability by improving the thermal stability of PET throughout the recycling process. Developed by PolyOne Corp., Avon Lake, Ohio, ColorMatrix SmartHeat RHC Reheat additive SmartHeat RHC is said to boost the thermal stability of PET and helps to minimize yellowing, which can help reduce the amount of toner or color required in rPET and PET bottles.
According to the company, as the level of SmartHeat RHC in the recycle stream begins to rise over time, the overall quality of rPET is improved, contributing towards increased levels of rPET content in PET bottles by addressing the root cause, rather than masking the issue. This in contrast to a typical remedy of adding toners and colorants which can have a detrimental effect on the brightness of the final product. PET is known to commonly yellow during the recycle process due to the heat exposure and subsequent thermal degradation.
SmartHeat RHC has been shown to improve preform and bottle color, clarity, mechanical strength, and processability, reducing energy consumption during the blow molding process. The additive allows for optimization of polymer weight distribution within the PET bottle. This helps in both improving the strength and the quality of the bottle, allowing for further lightweighting and improved blowing performance.
For applications requiring color or toning, SmartHeat RHC is also available as a range of recycle-friendly tints or toners for both rPET producers and converters. It’s important to note that this product is compatible solely with transparent bottles produced in a two-stage injection stretch blow molding process. SmartHeat RHC products are supplied in ColorMatrix approved packaging and are active as supplied. They are metered into the PET stream just above the feed throat of the injection molding machine or extruder, using a PolyOne supplied ColorMatrix liquid metering system. Melt processing of SmartHeat RHC products is carried out at typical PET processing conditions at recommended dose rates, which range from 0.02% to 0.10%. Once incorporated into the preform, no further action is necessary. Care must be taken to optimize the bottle blowing process due to the increased heat-up rate of the preform, to take advantage of the many benefits offered by this product range.
Volatility in HDPE and PP recycle prices; relative stability for R-PET.
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