electrical & electronic | Thermal management
Right: PolyOne sees strong
potential for its Therma-Tech conductive
compounds in LED lighting
acquisitions. Last October, for example, Celanese acquired the assets of Cool Polymers, which as the name suggests was a compounder focusing strongly on such materials. Celanese said at the time that Cool Polymers’ technical capabilities in the LED market “will allow for immediate customer growth while continuing to advance Celanese’s engineered materials business across thermal management and electrical conductivity polymer applications.” Cool Polymers’ portfolio includes thermally conductive thermoplastics and elastomers with and without electrical conductivity. Lanxess added Durethan TC thermally conductive
fi llers with conductivities as high as 35 W/mK. Non- conductive compounds containing mineral fi llers provide conductivities up to around 12 W/mK. Hardwick says RTP has been pushing thermally conductive compounds for around two years, but it is only now that signifi cant commercialisation of fi nished products is occurring. “Downstream understanding of how to use these compounds has come a long way in that time,” he says. “People are now coming to us with designs that are much more appropriate for thermo- plastics, they understand that they can’t use them as drop-in replacements for metals.”
RTP is also doing increasing business in replace- ment not of metals, but of non-conducting thermoplas- tics where just a moderate level of thermal conductivity is very useful for thermal dissipation. Without going into specifi cs, he says motor housings are a potential market for this type of materials replacement.
Right: RTP is making
compounds
offering both thermal
conductivity and EMI shielding
performance
Numerous other independent compounders are also emphasising thermally conductive compounds. Ensinger, for example, offers compounds based on a wide range of polymers and with different additives depending on the level of conductivity required, the processability, and price, and also the level of electrical conductivity required. It says components made of its Tecacomp TC provide thermal conductivity of between 1 and 25 W/mK.
Lehmann & Voss is another active
supplier, with its Luvocom range. It cites applications ranging from heat exchang- er plates in a polypropylene compound through to heat sinks for hospital operating theatre lights in a compound based on polyetherimide.
Other major polymer
suppliers are also making moves in conductive com-
pounds, either through internal development or through
28 INJECTION WORLD | March 2015
polyamides to its range last year. Its fi rst two grades are easy-fl ow polyamide 6 variations, Durethan BTC65 H3.0 EF and BTC75 H3.0 EF. Their high thermal conductivity is based on reinforcement with 65% and 75% of an undisclosed mineral component. “Both materials display a very good balance between high thermal conductivity, outstanding mechanical properties and good processing behaviour,” says Detlev Joachimi, head of Durethan product development at the company. “They have been approved by two international automotive suppliers”.
Conductive polyamides
The thermal conductivity (determined by the Nanofl ash test method) of the polyamide with 65% mineral reinforcement is 1.0 W/mK. The material with a 75% mineral content tested at 1.5 W/mK. Lanxess claims the two materials conduct heat as effi ciently as polyamides containing boron nitride or aluminium oxide. “However, aluminium oxide systems have the disadvantage of being very abrasive, which quickly causes damage to the injection mould. Compared to boron nitride systems, our materials are signifi cantly less expensive and have better mechanical properties. Furthermore, their thermal conductivity is virtually the same in all directions,” Joachimi says.
The products also have good mechanical
properties – on par in some cases with those of Durethan BKV 30 H2.0 – despite a high fi ller content. For example, Durethan BTC65 H3.0 EF is equally stiff and displays a similar elongation at break of 3%. Izod impact strength of 35 kJ/ m2 is more than twice as high as in comparable polyamide compounds with aluminium oxide fi ller, according to
Joachimi. DSM Engineering Plastics is another
engineering plastics producer that has been actively developing and marketing thermally
www.injectionworld.com
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