electrical & electronic | Thermal management
conductive compounds. One of its most recent applications is in large LED down-lights from market leader Osram which feature heat sinks made using its Stanyl TC ther- mally conductive polyamide 4,6. Chosen ahead of aluminium, Stanyl TC scores with its ability to be easily and quickly injection moulded into complicated geometries that effectively remove heat from around the LED light source, thus ensuring a long lifetime. The L and XL versions of Osram’s LedvanceCE series
Below: Osram is using a thermally conductive Stanyl PA4,6 from DSM in its Ledvance downlighter
are the first LED down-lights (lights that are built into the ceilings of shops, offices, and domestic accommo- dation) from the company with a heat sink in plastic rather than in aluminium. Stanyl TC has sufficient thermal conductivity (up to 14 W/mK) to successfully dissipate the heat generated by the LED; DSM says that the compound also has the excellent flow properties common to all polyamides that enable it to be moulded into complicated shapes with high surface-to-volume ratios to enhance heat dispersion. Osram was also able to reduce the weight of the housing by around 50% compared to aluminium. This simplifies installation of the luminaire and enables the use of spring fixations in the ceiling. The material complies with flammability requirements according to IEC and UL safety standards. As well as Stanyl TC thermally conductive polyamide 4,6, DSM offers TC grades of Arnite PET for automotive lighting applications, and it is now also introducing Akulon TC based on polyamide 6. This is aimed in particular at LED lighting producers looking to reduce their costs in what is becoming an increasingly competitive market. It has already been adopted by some companies in China. According to Wu Rui, application development and
technical service manager with DSM in China, Akulon TC’s conductivity, which is in the range of 1-2 W/mK, is sufficient for these applications, especially for hybrid designs that use over-moulded metal inserts. “For LED
Left: The Tivedo lamp by Luceplan uses a thermally
conductive PA6 from Lati for its stylish moulded heat sink
lighting customers, we need a balance between TC value, processability, mechanical properties, reliability and cost,” he says. In Italy, lighting manufacturer Luceplan is using a
thermally conductive PA6 compound from Lati to produce the heat sink on its new Tivedo desk lamp. Designed by UK-based Sebastian Bergne, the lamp uses the injection moulded heat sink as both a functional component and a styling feature – the cooling fins become a decorative element in the new design. The heat sink is moulded in Lati’s Laticonther 62GR/50 PA compound, which contains 50% by weight of graphite to provide a thermal conductivity value of more than 10 W/mK. The Laticonther grade is opti- mised for production of the thin wall sections required for natural convection heat sinks while its density, at around half that of aluminium, helps keep the weight of the swivelling lamp head to the minimum. Lati’s Laticonther thermally conductive compound is also being used by German company BVR Electronic in its latest Varioline LED lighting range for swimming pools. In this case the company has selected a PC com- pound – Laticonther 87/28GR/50 – which incorporates 50% graphite to ensure the LED temperature does not exceed 40˚C. Aside from good thermal conductivity and moulding performance, BVR also needed a polymer with good dimensional stability to ensure a watertight seal would be maintained between the heat dissipating backplate and transparent PC lens cover. Bayer MaterialScience (BMS) claims that its
thermally conductive Makrolon TC8030 PC resin provides a cost effective alternative to aluminium in the produc- tion of LED lighting components by allowing higher levels of functional integration to simplify assembly. Suitable for production of injection moulded heat sinks, the TC8030 grade offers thermal conductivity values of up to 22 W/mK (measured in accordance to ISO 22007-2) and is claimed to be low density and easy to process. With demand increasing for high temperature
resistant thermoplastics for applications such as luminare housings, BMS last year announced its decision to invest in additional capacity for the specialty bisphenols used in its Apec high performance PC. The
30 INJECTION WORLD | March 2015
www.injectionworld.com
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