The spherical UHMW-PE fine powder Mipelon from Mitsui Chemicals Europe offers a high-performance alternative to PTFE in terms of sliding properties, abrasion resistance and chemical resistance in plastics, rubbers, paints and coatings.
Mitsui Chemicals Europe
The limiting factor substituting of PTFE is the lower melting temperature of UHMW-PE, which is around 135 °C. While Mipelon can generally be used at temperatures up to 120 °C, the speciality grade PM200C is suitable as an additive in hydrocarbon oil for temperatures of up to 200 °C. Unlike PE powder, it does not tend to swell at higher temperatures and retains its shape and function. It is also characterised by improved dispersing behaviour in plastic masterbatches.
In many cases, the same dosage results in a lower coefficient of sliding friction and improved abrasion resistance than with PTFE, enabling economical use. The density of 0.97 g/cm³, which is around half as high compared to PTFE, supports weight reduction.
Mipelon, whose molecular weight is around 2 million g/mol, is characterised by the small size of the special spherical particles. The average particle size (D50) for the PM-200 type is around 10 µm, which is currently the smallest size in the world for this product group. For the XM-220 type, the D50 value is around 30 µm and for XM-330 it is 65 µm. The coarse particle grades are used for the modification of rubbers and plastic compounds and as filters. In contrast, the finer powder grades are ideal for paints and coatings.
The spherical particles with their smooth surface and narrow particle size distribution support very good dispersion. The particle size distribution of Mipelon is significantly narrower than that of PTFE, and it also has a considerably lower proportion of coarse particles. The material exhibits lower coefficient of friction (COF) and abrasion values under long-term stress not only compared to PTFE but also compared to PA11 and PA12 as well as PE waxes.
Mipelon is also characterised by its high chemical resistance to acids, alkalis and organic chemicals. It absorbs virtually no water or moisture. Most types are suitable for food contact applications in accordance with EU and US legislation.
Due to this broad spectrum of properties, applications range from coatings, including electrostatic powder coatings, water- or solvent-based spray coatings and dip coatings, to the modification of rubber and thermoplastics. Examples of applications include rubber-coated rollers, coatings of rubber profiles for the automotive industry, polymer compounds, anti-blocking for films instead of zeolites and silicon, oils and greases with emergency lubrication.
Together with customers, Dreyplas and Mitsui Chemicals Europe are developing solutions to replace PTFE with UHMW-PE and to optimise tribological properties. This also includes the use of Lubmer UHMW-PE, which is available in granulate form and has been developed by Mitsui Chemicals for extrusion and injection moulding applications.