COMPOUNDS | THERMALLY CONDUCTIVE


Engineer at Celanese. Another metal transition project for a manufac-


Above: CoolPoly compounds from Celanese have been used in automotive headlamp heat sinks, replacing aluminium


back to the 2014 purchase by Celanese of substan- tially all the assets of US-based conductive polymer compounder Cool Polymers. That saw Cool Polymers’ formulation, prototyping, moulding and testing capabilities combined with Celanese’s polymer chemistry, compounding operations and part design. Today, Celanese manufactures two classes of thermally conductive plastics. The CoolPoly TCP E series use carbon additives to impart thermal conductivity. ESD and EMI shielding grades are available, with commercial grades offering thermal conductivity as high as 35 W/m·K. These grades are also electrically conductive (when carbon additives are used) and are available based on matrix materials including PA6, LCP or PPS. The Cool Poly TCP D series are electrically insulating, using ceramic additives to provide thermal conductivity. Commercial grades deliver up to 10 W/m·K.


Right: Lati and Protool Plastics used their thermal


analysis service in development of the PA6 heat sink for Whitcroft Lighting’s Mirage 3 LED luminaires


Sensing success The company says it recently helped an automotive parts manufacturer transition from a non-conductive thermoplastic to a thermally conductive material, based on Celanese’s Vectra LCP brand, for produc- tion of EV battery temperature sensors. The CoolPoly solution delivered improved mould filling, enabling the part size to be reduced. The com- pound also provided UL94 V-0 flame retardance at 1mm wall thickness. “Critical to the function of the part,


the transition to the thermally conductive material reduced the reaction time of the temperature sensor from 30 seconds to just 14 seconds,” says Dr Prabuddha Bansal, Principal Research


22 COMPOUNDING WORLD | September 2023


turer of electronic housing units (ECUs) involved the use of a CoolPoly PA6-based grade of conduc- tive material. The material change resulted in a 45% weight saving (from 185g to 100g) with a comparable reduction in total part costs. Accord- ing to Celanese, the thermoplastic part met all mechanical and heat dissipation requirements and provided EMI shielding up to 50 dB. Bansal says that CoolPoly materials have also been used in heat sinks as a replacement for aluminum in automotive headlights. He also says multiple CoolPoly grades are in use along with non-conductive Celanese materials in EV charg- ing stations. However, he emphasises the impor- tance of early and close involvement with the customer. “Materials suppliers always prefer to be involved in a project at an early stage, but with thermally conductive materials, this early-stage collaboration is even more important as these highly filled materials can require a soft touch when processing,” he says.


Expert analysis A further example of a collaborative approach to thermally conductive projects can be seen in the partnership between Italian compounder Lati and UK-based injection moulder The Protool Plastics Group. The former has combined its expertise in thermally conductive formulations with the latter’s knowhow in production and tooling for polymer heat sink products to jointly launch a thermal analysis service for heat sink development. The two companies offer a complete project development service within the UK market, which includes provi- sion of thermal analysis to optimise heat sink design and ensure effective material selection. Simulation of thermal performance of the plastic heat sink is performed based on the customer’s


boundary conditions, such as the working


temperature of the device and the


IMAGE: THE PROTOOL


PLASTICS GROUP www.compoundingworld.com


expected environmental temperature. The simulation uses CAD files developed for mould tool design and allows for improvements in the design geometry of the part and tool. It includes flow simulation with Autodesk Moldflow and thermal simulation using Ansys, with material characterisation


IMAGE: SHUTTERSTOCK


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