Published 11/19/2024

Fine Powder Substitutes PTFE in Plastics, Rubbers, Paints and Coatings

Together with customers, Dreyplas and Mitsui Chemicals Europe are developing solutions to replace PTFE with UHMW-PE and to optimize 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 molding applications.

Powder Coating

Edited by: Lori Beckman

Executive Editor, Products Finishing

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. The limiting factor in the substitution of PTFE is the lower melting temperature of UHMW-PE, which is around 135°C. While Mipelon can generally be used at temperatures of up to 120°C, the specialty 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 even at higher temperatures and retains its shape and function. It is also characterized by improved dispersing behavior in plastic master batches.

In many cases, the same dosage results in a lower coefficient of sliding friction and improved abrasion resistance than with PTFE, which enables economical use. In addition, the density of 0.97 g/cm³, which is around half as high compared to PTFE, supports weight reduction. Mitsui Chemicals Europe sells Mipelon directly and via its distributor Dreyplas, which also supports customer-specific new and further developments.

Mipelon, whose molecular weight is around 2 million g/mol, is characterized by the small size of the special spherical particles. The average particle size (D50) for the PM-200 type is around 10 microns, which is currently the smallest size in the world for this product group. For the XM-220 type, the D50 value is around 30 microns and for XM-330 it is 65 microns. 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. Mitsui Chemicals in Japan is currently developing powder grades with a D50 value of less than 5 microns and around 6 microns. The latter is already available for sampling. Commercial availability is planned for the end of 2025.

In general, the spherical particles with their smooth surface and narrow particle size distribution support good dispersion. The particle size distribution of Mipelon is significantly narrower than that of PTFE, and it also has a lower proportion of coarse particles. In addition, 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. In addition, it absorbs virtually no water or moisture. Most types are suitable for food contact applications in accordance with EU and U.S. legislation.

Due to this spectrum of properties, typical 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.