ADDITIVES | PROCESS AIDS/LUBRICANTS
cal plastics and fibre filled compounds. For applications in polar plastics Euroceras offers PE/ MAA-copolymer waxes and synthetic polyester waxes, which it says have properties similar to those of montan waxes.
Pitched for PVC It is close to 10 years since the European PVC industry made a voluntary commitment to move towards more sustainable additive systems and to aim to switch to renewable sources. “In that respect, the European PVC industry is committed to use bio-based additives whenever they provide at least the same performance level as convention- al, fossil-based additives,” says speciality chemicals producer Emery Oleochemicals. Emery’s Green Polymer Additives (GPA) busi- ness unit develops high-performance polymer additives including a wide range of lubricants particularly suitable for PVC applications. Most of these additives, branded Loxiol, are produced from bio-based materials. The company says that external lubricants for
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Bruggolen TP-P180 has a substantial effect on flow in semi-aromatic polyamide
PVC help reduce mechanical impact and shear rate of extruder screws and calender rolls, leading to an extension of gelation time. Since external lubri- cants need to migrate to the surface of the PVC during processing, they need to be only minimally compatible with the PVC matrix. As PVC is a quite polar polymer, non-polar additives such as paraffin waxes and polyethylene waxes typically work well as external lubricants. But they are not the only options, says Dr Christian Müller, Global Technical Market Manager in Emery’s GPA BU. “It may be surprising to learn that ester waxes can
also be external PVC lubricants although they have polar ester functions, and potentially additional polar functions, in their molecule,” says Müller. He explains that in a recent belt extrusion study, external ester waxes showed very similar or the same performance characteristics as hydrocarbon waxes with regards to gelation and extrusion data as well as gloss
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and static thermal stability of the extruded belts. “External ester waxes also demonstrated benefits when it comes to the additive’s volatility. The lower the additive volatility, the lower the loss during processing to the degassing unit and the lower the risk some deposits will form due to condensation at the die or in the calibre,” he says. “Conventional hydrocarbon wax lubricants can be replaced by tailored ester lubricants with high bio-based content to provide effective external lubrication.”
PA flow enhancement Away from waxes, what is claimed to be the first flow enhancer for semi-aromatic polyamides was introduced by Brüggemann at last year’s K exhibition. This product joins Bruggolen TP-P1507, which is already widely used for aliphatic polyam- ides such as PA6, PA66 and PA12. The company says that both additives demonstrate very signifi- cant improvement in melt flow while retaining the mechanical properties of finished components. Supplied in pellet form, they are said to be easy to dose and disperse during direct injection moulding and compounding. Trials carried out with independent testing
laboratory RJG Technologies showed that Brug- golen TP-P1810 enabled an in excess of 20% cycle time reduction during moulding and, significantly, allowed filled compounds containing 50% and more of glass fibre to be injection moulded into intricate and complex shapes. For instance, during moulding tests, the flow spiral of a semi-aromatic polyamide reinforced with 50 wt% glass fibre was lengthened by 70% at a dosing rate of Bruggolen TP-P1810 of only 1.5%. “Much-improved colour and appearance of the
resultant moulded parts are a welcome result of the excellent processing enabled by Bruggolen TP-P1810,” says Dr Klaus Bergmann, Head of Polymer Additives at Brüggemann. “Alternatively, by allowing a 30°C reduction in melt temperature, the additives clear the way to gentler processing and reduced energy consumption.” Bergmann says the products are different from anything else on the market, both in terms of their chemistry and efficiency. “They are not just a mixture of different lubricants, as some others are. The product form is polymeric granules.”
CLICK ON THE LINKS FOR MORE INFORMATION: �
www.clariant.com �
www.voelpker.com �
www.euroceras.com �
www.emeryoleo.com �
www.brueggemann.com
48 COMPOUNDING WORLD | April 2020
www.compoundingworld.com
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