HIGH PERFORMANCE COMPOUNDS | MATERIALS
PPA grades reinforced with 20% carbon fibres
are about 20% lighter than PA6 or PA66 containing 50% glass fibres (both by weight). BASF says the tensile strength of a 20% carbon fibre reinforced Ultramid Advanced compound is either better or equivalent to a 50% glass fibre reinforced polyam- ide while showing better processability. Ultra- mid Advanced N3HC8, for example, displays very good stability after ageing at high temperatures: it retains nearly 100% of its tensile modulus after heat aging at 120°C for 5,000h or at 150°C for 3,000 hours.
Independent compounder Lati recently launched compounds based on PA9T under the Laramid T brand. It says it is pitching them at strategic industrial sectors, such as connectors and e-mobility, where resistance to high temperatures is required together with the ability to withstand prolonged stress and aggressive environments.
Critical threshold The compounds maintain good mechanical properties up to a continuous use temperature of 150°C, which Lati Group Technical Assistance and Marketing Director Luca Posca says is a critical threshold for many application sectors. “This feature allows PA9T to compete with other PPAs and PPS as well in automotive, appliance, energy management, electronic and electrical devices,” he says. “Laramid T is an already fully developed group
of materials, featuring glass and carbon fibre reinforced grades for structural applications, thermally and electrically conductive as well as self-lubricant compounds. Halogen and red phosphorous-free flame retardants are already available in both reinforced and unreinforced versions and UL approval is on its way,” he says.
Very long fibres In response to the growing interest in LFT com- pounds based on high temperature polymers, RTP Company can provide standard and custom
www.compoundingworld.com
RTP’s Very Long Fiber Compounds show improved impact resistance when compared to short fibre compounds based on the same polymer Source: RTP Company
November 2021 | COMPOUNDING WORLD 61
engineered Very Long Fiber (VLF) Compounds that provide improved temperature and impact resistance compared to short fibre alternatives. The company says the compounds also provide material advantages in a broad range of applica- tions — including medical equipment and energy applications as well as automotive — due to their lesser-known property attributes such as abrasion resistance and dimensional stability. “Because they have fewer fibre ends, long fibre compounds offer advantages in applications where abrasion to the mating surface is a concern,” says Brett Weishalla, Senior Product Development Engineer at RTP. “This can lead to significant improvement in the longevity of a plastic product and mating part.” When long fibres are incorporated, compounds based on PPS, PEEK, PPA and PEEK show all the same benefits as the more typical polyolefin and polyamide-based LFT compounds. Parts moulded with VLF Compounds hold their dimensional stability, says RTP, due to the length of the long fibre reinforcement, which forms an internal skeletal structure that helps prevent part shrinkage after moulding.
In addition to impact resistance, temperature
resistance, and lower abrasion, VLF Compounds based on high temperature polymers are frequent- ly selected for their outstanding chemical resist- ance. The same features of the polymer backbone that give the compounds their temperature resistance typically provide the ability to resist chemical attack, it says. “While it is always important to understand the
application and environment, it is especially critical when considering high temperature compounds because over-engineering can impact the price
Left: An
automotive part before and after burn-off of the polymer. The after photo shows the skeletal structure created in RTP’s Very Long Fiber compounds, which helps provide
dimensional stability
IMAGE: RTP COMPANY
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