ADDITIVES | POLYAMIDES
Right: BYK- MAX CT 4260 FR allows HFFR flame perfor- mance to be met at reduced filler levels
reinforced with 50 wt% glass fibre was extended by 70% using a 1.5% addition of the flow enhancer, with a resulting improvement in the ability to flow in complex shapes. Brüggemann’s heat stabilisers include TP-H1805 for higher temperatures, such as found in turbo- charged engine applications, and TP-H1607 and TP-H1803 for longer mechanical performance retention times at different temperatures. Brug- golen TP-H1803 Phenolic Plus is a new heat stabiliser for polyamides designed for applications where the part is primarily exposed to tempera- tures below 150°C but that reaches short-time peak temperatures of up to 180°C, says Bergmann. Its ability to withstand these higher peak temperatures is an advantage over conventional stabiliser blends produced with hindered phenolic antioxidants and organic phosphites, he says. Phenolic Plus is supplied as easily dosed and dispersed, dust-free pellets. According to Brügge- mann, it can be used at lower dosages than conven- tional phenolic/phosphite blends to achieve the same level of effect. Applications with continuous exposure to temperatures above 150°C do call for the use of copper-based stabilisers, says Bergmann.
Below: The higher power handling of today’s USB-C connectors requires improved flame retardance
Burning issues Joerg Garlinsky, Head of Global Enduse Thermo- plastic Industrial Applications at BYK, says that the trend towards hybrid engine technology, which uses downsized combustion engines that result in higher heat generation, increases the need for performance additives in the engine compartment. He adds that in the long-term, if e-mobility be- comes established as expected, demand may shift to additives for battery housings, which also have high requirements for stability. Flame retardancy is already critical for many polyamide end-uses, including transportation and electrical and electronic (E&E) applications. New synergists aim to improve halogen-free formula-
tions. BYK’s flame-retardant synergist BYK-MAX CT 4260 FR is said to improve flame retardant proper- ties and allow reduced levels of aluminum or magnesium hydroxide fillers to be used in HFFR compounds. This reduced filler loading improves processing, physical properties, and weight. BYK says that in HFFR formulas, the synergist improves dropping behaviour and crust formation. The additive is an organoclay based on a montmorillonite mineral with an organic surface treatment. It is easily dispersed in polyamides with standard compounding equipment, according to Garlinsky. In addition to improving fire retardancy properties, it can also enhance barrier to oxygen, water vapour, and hydrocarbons, the company says. A mineral filler synergist for phosphorous-based
flame retardants in polyamides is also in develop- ment at HPF The Mineral Engineers, a division of Quartzwerke. Its kaolin and wollastonite combina- tion can save cost by reducing the amount of flame retardant required while improving some proper- ties, such as tensile elongation, modulus, and HDT.
Making connections Changes in the electrical and electronics market will also affect polyamide materials and additives, DSM’s Sadiki said in a presentation at AMI’s Performance Polyamides conference in the US last year. USB-C connectors, for example, handle more power than previous generations so high compara- tive tracking index (CTI) and V0 flame retardancy at narrow wall thickness is needed for product reliability (the higher CTI reduces the risk of connector failures due to arcing and short circuits). The challenge for a flame retardant compound in this application, says Sadiki, is to achieve a UL94-V0 formulation down to 0.18 mm wall thickness while still delivering a combination of high material flow, high mechanical strength, low warpage and high CTI (600V). He said DSM’s testing has shown that a PA46 compound with a
58 COMPOUNDING WORLD | February 2020
www.compoundingworld.com
IMAGE: SHUTTERSTOCK
IMAGE: BYK
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