Swedish compounder Hexpol (Malmö; www.hexpol.com) has launched “Dryflex HiF”, a range of high melt-flow and scratch-resistant thermoplastic-elastomer compounds. The TPS-SEBS materials have a density of 0.9 g/cm³ and were developed for injection-moulded large parts, primarily surfaces in automotive interiors. Due to good abrasion behaviour and processability, the supplier sees this as an interesting alternative to polyurethane coatings, PVC slush moulding or TPO film processes commonly used to date. Dryflex HiF TPE is suitable for multi-component applications in direct, back injection moulding with polypropylene.

In a pilot test, 1.1 mm thin TPE skins were injected for the soft surface of a complete instrument panel and back-foamed with PU. Further tests had shown that the strict requirements for UV and heat resistance for instrument panels (120°C for 1,000 hours) were also met. A non-glossy, matt surface without visible weld lines can also be achieved, as is the detailed reproduction of various leather grains.

Injection moulding large components with TPE enables shorter cycle times than traditionally used for these applications. Product manager Thomas Köppl said, “The production of a surface in PVC slush moulding can take five to six minutes, whereas the production of an injection-moulded TPE cladding requires only about 80 seconds.”