New plain bearing material for food contact

Many designers face pressure when sourcing plain bearings for food processing machinery, as they must increasingly take regulatory requirements into account. While potential restrictions on PTFE are being discussed, new regulations are already tightening the requirements for food-contact materials containing bisphenol. To provide designers with long-term regulatory certainty, Igus is now launching the new iglidur A181PF plain bearing material, which does not contain these controversial chemicals.

Plain bearings are an indispensable component of food processing machinery. They are used in swivel arms, guides, flaps, and rollers. However, procurement is becoming increasingly complex for designers. This is because they must now consider more than just hygienic and functional aspects. Attention is also turning to controversial chemicals, the use of which may be subject to stricter regulations in the future. One example is polytetrafluoroethylene (PTFE), a chemical that belongs to the so-called PFAS group. Some PFAS are suspected of being harmful to humans and the environment. For this reason, the European Chemicals Agency (ECHA) is currently reviewing a restriction proposal submitted by several member states. EU Regulation 2024/3190, which will prohibit the use of bisphenols in food-contact materials in the future, is adding further pressure. “We have therefore developed the new A181PF plain bearing for food processing machinery, which does not contain PTFE or bisphenols,” says Dr. Magnus Orth, Head of the Igus Materials Center.

Igus Material Researchers Find an Alternative to PTFE

At Igus, PTFE has always played a key role in plain bearings when it comes to low friction coefficients and good dry-running properties. The search for an alternative was correspondingly complex. “Developing a plain bearing that does not use PTFE meant completely rethinking the tribological properties,” explains Dr. Magnus Orth. The task was also complicated because applications involving food contact impose additional requirements: for example, high resistance to cleaning and media, as well as stable mechanical properties. “We tested many material combinations until we found a solution. The new material is based on a combination of alternative solid lubricants and an optimized polymer matrix, which together result in a robust, food-grade overall profile.” The plain bearing is resistant to shocks, impacts, and edge pressures; it operates reliably at temperatures ranging from -50 °C to +90 °C; and, depending on the application parameters, achieves a service life comparable to—or even better than—that of the PTFE-containing standard material iglidur A181. In its in-house test laboratory, Igus rotated the PTFE-free bearing at 0.3 m/s and a load of 1 MPa on a steel shaft. Wear amounted to only 0.57 µm/km. This wear depth is not visible to the naked eye; it corresponds to less than one-hundredth the thickness of a human hair.

Hygienic dry operation and high resistance to cleaning agents

The alternative solid lubricants are finely dispersed within the high-performance plastic iglidur A181PF. They enable low-friction dry operation without external lubricants. As a result, plain bearings made from this new material are suitable for use in the hygiene-critical food industry, where lubricants pose a contamination risk. The bearings meet the requirements of EU Regulation 10/2011 and the FDA for food contact. Furthermore, the material is free of bisphenol A, bisphenol derivatives, and their salts, and thus also meets the requirements of EU Regulation 2024/3190 regarding BPA in food-contact materials. This makes the material particularly suitable for applications in which food may come into direct contact with machine components. It also exhibits very high resistance to cleaning chemicals and low moisture absorption, allowing it to be installed with minimal clearance. Dr. Magnus Orth: “Customers can be confident that the material meets the strict requirements of the food industry, thereby offering additional planning certainty in light of future regulatory developments.”