AUTOMOTIVE | UNDER THE HOOD
Above: Thermoplastic elastomer hybrids (TEH) from Kraiburg TPE have a number of applications, including under-the- hood
ed to high service temperatures, including front- end modules, front brackets and under-the-hood components. Hexpol TPE has developed materials for adhesion to polyketone substrates during multi- component injection moulding. The company says that the TPE compounds open new possibilities in application development and product design. “The new compounds are another example of the high-performing materials we’re delivering for the automotive industry,” says Thomas Köppl, Group Product Manager. “We’re giving our customers solutions to those hard to solve techni- cal challenges. Those include for example materials with adhesion to diverse engineering thermoplas- tics for complex part geometries.” Polyketones have an elevated melting point (220-255°C) and are often used for high- performance applications in the automotive industry and technical components in mechanical engineering. In addition to good resistance to chemicals and hydrolysis, polyketones are characterised by their high wear resistance. The special TPE compounds expand the group’s Dryflex 2K portfolio of adhesion grades. They do not require the use of a primer or adhesive to adhere to polyketone, which makes the production process more economical, faster and simpler. The Dryflex B177 compounds are available in various degrees of hardness in the range of 40-70 Shore A. They also offer adhesion to a range of engineering thermoplastics such as PA, ABS or PMMA, and their related blends. (See also TPEs feature, p41.) Kraiburg TPE has introduced a new technology
platform for thermoplastic elastomer hybrids (TEHs), to close the performance gap between thermoplastic elastomers and conventional
28 INJECTION WORLD | May 2020
elastomer compounds. The TEH compounds are tailor-made to fit customers’ specific applications. Combined with selected elastomers, the com- pounds provide the same features as elastomers while maintaining the workability of TPEs. The company adds that TPE manufacturers have been trying to find ways of providing the perfor- mance of classic elastomers in their products. Although there have been a few successes with thermoplastic copolyester elastomers (TPCs) and thermoplastic polyamide elastomers (TPAs), it has not previously been possible to find a “universal super-TPE” that could match the properties of elastomers or rubbers. “To close the performance gap between established TPEs and elastomers, particularly in relation to thermal resistance, we are therefore taking an approach that focuses rigorously on applications and customers,” says Dirk Butschkau, Head of Business Development EMEA. “For example, we select the proportions of elastomers and thermoplastics in each compound on the basis of their specific compatibility and suitability for the required application temperature, chemical resistance and mechanical performance.” The result is a custom-engineered TEH compound with a completely crosslinked elastomer component – which in contrast to conventional elastomer mixtures can be processed just as economically for injection moulders of technical thermoplastics. The finishing that is usually necessary with most elastomers is not necessary and even sophisticated two-component applications with PP, PBT or PA can be implemented without bonding agents. The new technology platform provides advanced TPE materials with a hardness range of 55-80 Shore A, with significantly improved perfor- mance based on different combinations of elasto- mers and thermoplastics. Along with good me- chanical properties, the materials provide continuous operating temperatures up to 150°C and chemical resistance to oils, greases, lubricants and fuels. In addition, they remain completely recyclable, as the material is not crosslinked during the production of mouldings from TEH. According to the company, the thermoplastic
workability of TEH compounds may reduce the cycle time at comparable wall thicknesses by up to 80% in comparison with elastomers. This means they provide not only an extremely cost-effective alternative but also a wide range of possible new applications. The processing and characteristics profile are aimed particularly at parts of engine covers, oil sumps, fuel filler caps and oil caps, as well as cooling and/or temperature control units.
www.injectionworld.com
IMAGE: KRAIBURG TPE
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