A cooperation between German compounder and distributor Lehmann & Voss (LuV, Hamburg; www.lehvoss.de/eng) and surface coatings specialist Impreglon (Lüneburg / Germany; www.impreglon.de) has resulted in the development of a process that combines injection moulding and electrostatic powder coating to produce components in materials including PA 6 and PEEK and coating with them thermoplastic tribopolymers – materials that lubricate while reducing friction and wear – such as POM.

In standard carbon fibre-reinforced thermoplastics, if the wear resistance and coefficient of friction are not sufficient for the application, the materials are modified with lubricants, which reduces their strength. This led the two companies to develop the technology to reach a balance of tribological and mechanical properties in the materials.

In the process, the material of the injection moulded component is adapted and optimised for the coating system, which consists of a primer and a thermoplastic layer with a thickness of 100 micrometres (µm). The lubricant-modified surface of the coating exhibits a coefficient of friction (COF) of 0.06 against steel.

The companies said that, unlike injection moulded parts, the POM layer is not affected by a cold tool surface. Instead a highly crystalline morphology forms on the surface, ensuring high wear resistance and a matt surface. In tests, 27.3 cycles are required to abrade one µm.

Luvocom recently introduced its new "Luvocom SCF" range of carbon fibre-reinforced thermoplastic polymers. The family is reported to have particular viscosity in combination with high rigidity and stiffness, and can be processed on standard injection moulding machines.