MATERIALS | HIGH TEMPERATURE PLASTICS
An automotive part, before and after burn-off of the polymer; the after photo shows the skeletal structure created by Very Long Fiber compounds, which provide excellent dimensional stability
Mocom says its new Alcom LB PC-HT 1000 WT1102-19 extends the Alcom LB product range of light-blocking materials to high heat polymers. Based on a high-temperature polycarbonate, it has a Vicat B50 of 182°C and an HDT/A (1.8 MPa) of 154°C – significantly higher than standard PC. Alcom LB PC-HT was developed for applications
such as reflectors and light wells of touch control displays of appliance applications with high heat requirements, but Mocom says it could also suit any other application where high reflection and very low light transmission in an environment exposed to high heat is required. “This material can effectively separate light
release, smoke release and toxicity properties in the aerospace industry. Eurotec says polyaryl sulfones can be preferable due to cost advantage compared to, say, PEEK. For example, Tecotek ES20 WH100 HR 0A (PESU), and Tecotek EP20 WH100 HR 0C (PPSU) meet OSU heat release requirements OSU 55/55 and OSU 65/65, respectively. “If a higher service temperature is required in aviation, PEEK is the right material to withstand up to 260°C,” says the company. Additionally, PEEK grades stand out for their usability in metal replacement due to a good combination of lightness, high thermal resistance and mechanical properties for metal replacement. Glass fibre reinforced Tecopeek has a wide range of uses in structural applications. In response to continuing interest in long fibre compounds based on high temperature polymers, RTP Company offers standard and custom engineered Very Long Fiber (VLF) Compounds that provide temperature performance and superior impact resistance compared to short fibre alternatives.
“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 Company. “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 PA compounds. In fact, says RTP, parts moulded with VLF Compounds hold their dimensional stability due to the length of the long fibres, which form an internal skeletal structure that helps prevent part shrinkage after moulding.
22 INJECTION WORLD | September 2021
sources in a confined space and improve the light output at the same time with its high reflectivity of 92.5% and a transmission of only 0.3% through a 0.5 mm wall,” says Mocom. It has a GWIT of 875°C at 1 mm, which meets the requirements for insulation materials for non-supervised appliances in contact with active parts (current over 0.2 A) according to DIN EN 60335-1. Its UL94 flammability rating is HB. The company also has new grades of Tedur PPS with high levels of filler to provide EMI shielding. One of these, Tedur L 9904-1 BK0002-00, is said to have good dimensional stability at high tempera- tures as well as good processability. It has a UL94 V-0 rating at 3mm, thanks to the inherent flame retardancy of PPS.
PPS polymer does have a low comparative
tracking index (CTI) though; normally it is around 100V. A high CTI decreases the minimum creepage distance of an insulator and so helps to reduce distance between electrical conducting parts in an apparatus. But Tedur HTR PPS 2465 IM 16049 BK0002-00 has a CTI of 600V, so it can be used in high voltage applications requiring high tempera- ture resistance. “The increased thermal conductivity of Tedur HTR of 1 W/m.K complements the profile,” says Joachim Bernhard, Director, Global Market- ing, Electrical & Electronics.
CLICK ON THE LINKS FOR MORE INFORMATION: �
www.basf.com �
www.kuraray.eu �
www.lati.com �
www.dupont.com �
www.dsm.com �
www.domochemicals.com �
www.solvay.com �
www.gharda.com �
www.eurotec-ep.com �
www.rtpcompany.com �
www.mocom.eu
www.injectionworld.com
IMAGE: RTP
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