COMPOUNDS | THERMALLY CONDUCTIVE
“Heat removal in EV motors is an important
Above: Celanese says heat sinks in heads up displays are a target area for its thermally conductive CoolPoly TCP compounds
exit a vehicle by delaying the propagation of a fire beyond the battery pack for as long as possible. A key consideration is the proper selection and deployment of fire protection materials. Venkatakrishnan Umamaheswaran, SABIC’s
Global Automotive Marketing Director, said: “UL Verification for the thermal runaway protection of Stamax 30YH570 resin is a significant milestone in our development of polymer materials for today’s rapidly evolving EV battery systems. By providing cost-effective, lightweight plastic solutions, SABIC is helping to advance EV technology.”
New applications In August, SABIC joined forces with Lubrizol to develop compatible material solutions combining soft and rigid materials. The solutions feature SABIC’s LNP specialty compounds and copolymers, which function as rigid substrates, and Lubrizol’s soft Estane ECO TPU materials, which are two-shot injection moulded onto the substrates. The SABIC thermoplastics may enable thin-wall moulding to reduce raw material consumption, or deliver chemical resistance for durability, while Lubrizol’s Estane TPUs are formulated with bio-based content and are manufactured at certified ISCC+ facilities. Potential applications for these complementary materials include laptops, cell phone cases, and other electronics devices where durability, drop protection and a non-slip surface are required. “We recognised an industry need for soft and rigid thermoplastic combinations that provide high performance and good bonding strength,” said Jane Cai, Senior Business Director APAC, Lubrizol. “But finding the right pairing can be time- consuming for customers. Lubrizol and Sabic combined our strengths and sustainable material portfolios to deliver proven compatible solutions that can help customers reduce their development time and costs and bring new designs and concepts to the market.”
44 COMPOUNDING WORLD | September 2024
topic,” said Joachim Floeck, Automotive Marketing at Celanese. “EV motors tend to overheat if an EV is driven quickly for a long period. In most cases this will impact the driving performance of the vehicle so it is important to manage the temperature in these motors.” Thermal management is important in all types of e-motors but could be more challenging for radial motors (versus axial motors) due the design of the stator. Floeck said Celanese is working on multiple projects with manufacturers and automotive OEMs, with the company providing expertise on part design, plastics processing, and bespoke development of compounds. Bus bars, especially the ones in EV batteries that connect inverter to e-motors, also are emerging as an interesting opportunity to add value with thermally conductive compounds as they connect to points that generate heat. Floeck said Celanese is already working with manufacturers who want to equip the insulation of these busbars with heat-dissipating functions (see article on High Temperature Plastics for more on Celanese’s materials for busbar and EV battery applications). Another commercial automotive application cited by Floeck involves the replacement of aluminium with thermally conductive CoolPoly TCP compounds for heat sinks in heads up displays (HUD). Requirements for these parts include high heat dissipation, easy processability, and low warpage. In addition, the heat sink needed to be directly screwed to the printed circuit board. The CoolPoly TCP grade eventually chosen was based on PA 6. Improvements versus the aluminium part included 40% weight savings and a reduction in the junction temperature at the LED/heat sink interface of 5-10°C. The excellent flowability of the compound enabled the moulder to form very thin ribs in the heat sink, increasing heat transfer efficiency.
Charging cables Thermoplastics are commonly used for charging cables and power adapters. The latest USB-C connectors have more than double the output of older charging cables and adapters so require materials with a high comparative tracking index (CTI) and superior bonding strength, along with material properties that enable strong weld lines and thin walls to minimise the risk of arcing and fire. While insert moulding produces structurally stable parts, electrical breakdowns can occur when gaps form between moulded parts. To achieve tight tolerances and a proper fitting, a material that
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IMAGE: CELANESE/GETTY
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