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Painting of exterior automotive parts, such as fenders, bumpers, tanks flaps, grilles, mirror housing, exterior trims, and rear quarter panels, is complicated by the necessity of separate operation lines for metallic and polymer components. The insulative nature of plastics is a challenge for in-line electrostatic spray painting. To overcome this, automotive part manufacturers often use temperature-stable thermoplastic grades and modify them with electrically conductive additives, such as carbon black. However, because of their high working dosage required, car end parts with additives present processing challenges and can yield decreased mechanical properties.
OCSiAl, the world’s largest manufacturer of graphene nanotubes, has launched the new TUBALL MATRIX 822 graphene nanotube concentrate specifically designed for PA, filled PPS, ABS, TPU, and PC compounds for injection molding. OCSiAl says the addition of the nanotubes creates a permanent and homogeneous electrical conductivity without “hot spots” in the range of 10^5–10^9 Ω·cm, while retaining the original key mechanical properties, such as durability and strength, and minimally impacting the host polymer matrix. Furthermore, a low working dosage of 0.1-0.3 wt.% of graphene nanotubes demonstrates only a limited effect on rheological properties and processability.
Graphene nanotube concentrate now enables in-line e-painting of plastic exterior parts together with metal components using electrophoresis, where previously, separate production lines were required. OCSiAl says benefits for manufacturers of polymer injection molded parts for automotive, industrial, construction, mining, and other applications include reduced production costs and reduction in the number of rejects without changing standard operating processes.
“The new product will also be valuable for improving automotive safety and tracking systems: graphene nanotubes allow makers to produce high-quality electrically conductive thermoplastic products without compromises in terms of overall product mechanical performance or durability,” said Vladimir Kravchenko, Development and Support Leader for Thermosets, OCSiAl Group. “We already see demand from manufacturers of fuel system parts including quick connectors, fuel pumps, valves, filter housings, EV-battery caps, and other car components.”