- Carolina IAQ
The utilization of post-consumer recycled material poses challenges for high-quality extruded and blow molded materials. Post-consumer recycled feedstock can contain various contaminants and unpredictable molecular weight distributions which can result in increases in black specks and gels in high quality film and blow molded products.
Polymer lines equipped with melt filtration can reduce and eliminate many of these defects, however on-line filter life can become problematic as the media will begin to plug at a faster rate. Cleaning melt filtration systems poses challenges due to the ever-changing additives and contaminants found in the post-consumer recycled material stream.
Carolina Filters services a range of polymer manufacturers and converters including producers and processers of polyester (PET), polypropylene (PP), Polyethylene (PE), and Polyamides (PA). When processing post-consumer recycled materials, advanced filtration is necessary at various stages in the production process. The processing of raw post-consumer recycled materials will often be filtered with recycling systems produced by manufacturers such as Maag Ettlinger Screen systems, Erema hot melt laser disc filters, and Femic punched and laser screens. For finer filtration during conversion to the finished product, candle filtration systems are often utilized. Manufacturers of these candle filtration elements include, but are not limited to: Pall, Maag, John Crane, Purolator, Bekaert, PTI, DWT, US Filters, and Porvair.
As we transition to a circular economy, the efficiency of processing post-consumer recycled material in high quality polymer applications is essential. Filtration is critical in the processing of post-consumer recycled materials by enhancing the quality and usability of recycled materials. To deliver the benefits of filtration, it is necessary to understand how fouled filters can be recovered for reuse. The diversity of contamination streams and contaminant loading in post-consumer recycled streams can pose a challenge for filtration systems. If these elements are not appropriately cleaned, they can result in premature clogging, high pressures upon installation, reduced efficiency of the filter and contaminant bypass into the melt stream. Carolina Filters carefully designs a custom cleaning profile for each customer to include specialized cleaning methods and technologies that target a wide variety of organic and inorganic contaminants found in the PCR stream.
Carolina Filters has successfully assisted many customers with PCR related filtration issues. We were contacted by a manufacturer of a laser melt filters who had a customer seeing decreased on-stream life with their filters. The customer processed parts through high-temperature cleaning cycles without success and were considering filter replacement. Carolina Filters worked with the customer to identify the source of their contamination and utilized targeted chemistries to fully remove the contamination from the fine screens. The screens were able to be returned to the customer’s process and performed like new.
On a separate occasion, a long-time customer of Carolina Filters began to introduce PCR into their melt stream during the manufacture of PET blow molded products. The introduction of the PCR resulted in failing of post-cleaning cleanliness tests at Carolina Filters after multiple processing through traditional cleaning methods. Carolina Filters worked to qualify a new cleaning technology for these filters to increase the efficiency of the cleaning protocol and reduce turnaround and costs associated with additional cleanings. A trial was designed using DEECOM® technology, and the combination of superheated steam and pressure swing cycles resulted in efficient removal of polymer and residual additives and contaminants from the PCR streams that traditional cleaning methods were leaving behind.
Validation of integrity and cleanliness is equal in importance to the actual cleaning process. Carolina Filters offers numerous testing methods to ensure the integrity and cleanliness of filters and parts following the cleaning process.