PURGING COMPOUNDS | MAINTENANCE


reducing downtime and scrap costs. The resulting cleaning extrudate can be granulated and reused, especially in cases of low contamination. It is also recommended for cleaning extruders during extended shutdowns, where it can help prevent contamination or deposit formation. According to the company, the J-1819 purging


material uses a combined chemical and physical mode of action that can clean both the surface and the inner layers of the equipment. Cevo-clean J-1819 has can be used up to 360°C (depending on the carrier polymer used) and will clean extrusion screws and barrel as well as die heads and adapters. Matthies offers some specific practical tips to compounders for effective and efficient purging and cleaning of extruders with Cevo-clean J-1819. These include preparing a dryblend mixture of Cevo-clean J-1819 with the unfilled polymer type that is to be used in production, or that which forms the basis of the new compound to be processed. The recommended mixing ratio is 20-25 parts Cevo-clean J-1819 to 75-80 parts polymer. The mixture should be processed on the extruder using the normal processing parameters of the polymer and an amount sufficient to fill the entire extruder and die head should be used.


Efficiency savings US purging compound producer Dyna Purge sees industry concerns over the impacts of labour shortages, the drive for manufacturing efficiencies, offsets to volatile resin prices and increasing interest rates encouraging use of CPCs. “Growth opportuni- ties in the market are associated with those not using CPCs. These companies need to understand the savings and efficiencies associated with CPCs compared with ‘in-house’ remedies,” says Bob Grzegorek, Technical Product Manager at the firm. “Other current market influences include that many companies prefer to use one universal purge with all types of resins. This makes it easier on the associates who perform the purging. Having to use multiple types creates opportunities for mistakes. Recyclability is becoming more important as well, with the ability required to grind and reuse clean purges,” he says. Grzegorek says ease of ‘post-purging’ is


particularly important. “Compounders need assurance that a CPC is completely removed from the system before starting the next production run. Ease-of-use with defined procedures is also required. A CPC provider that offers training and optimisation of the purge process is highly valued.” Dyna-Purge says its focus is on mechanical purges with wide heat ranges, providing ease-of-


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Left: Asaclean purging compound being peeled away from the screws


use across multiple processes and resin types. The company provides a non-abrasive scrub utilising a ‘scrubbing polymer’ for this purpose, with its latest development being Dyna-Purge L, a CPC that is said to use an easier flow carrier matrix that works well in both single- and twin-screw applications. Grzegorek’s practical tip for compounders for


effective and efficient purging and cleaning of extruders is to fill the flights completely without overfilling for twin-screw applications. “Utilising a ‘disco purge’ procedure while maintaining full flights is best practice,” he says. “Increasing die and adaptor heats, if applicable, will also help release stubborn pigments and dyes at 10˚C (50˚F) mini- mum or hotter, without exceeding recommended temperatures for your equipment or resin system.” The challenges posed by new resins, com- pounds and alloys in plastics compounding for effective and efficient cleaning of extrusion machines are highlighted by Asaclean. “To meet the needs of sustainable and competitive busi- nesses, purging compounds have been developed to offer solutions such as concentrates and specific purges for different processing needs including broader temperature ranges, as well as providing compatibility with various production mixes or base resins,” says Hector Sanchez, National Sales Manager. “The current market for purging compounds is


growing and competitive, as plastic processors are increasingly aware of the benefits of using a commercial purging compound for waste reduction and process efficiency. Any machine with a screw


December 2023 | COMPOUNDING WORLD 51


IMAGE: ASACLEAN


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