Lewatit® Ion Exchange Resins and Lewabrane® membrane elements for reverse osmosis in the automotive industry


There can hardly be any other branch of industry where the physical, chemical and esthetic demands on surface finishing are as high as in bodywork coating in automotive engineering. The coating has to be long-lasting, resistant to environmental influences and mechanical stress and still look perfect in order to convince the vehicle buyer.

When these kinds of multi-layer coatings are being manufactured,
cleaning steps are essential, and these use desalinated and softened water that must also be entirely free of organic suspended particles and microparticles. Ion exchange has a proven track record for producing this kind of water or treating it for re-use – where necessary combined with membrane processes such as reverse osmosis or ultrafiltration.

For example, demineralized water is required to clean the body framework after it has been pretreated with sandblasting and cathodic dip coating. This water must, above all, be free of silica and silicates, as they would have a detrimental effect on the outcome of the coating process. Precisely this removal of silica can be achieved very efficiently and reliably using special, extremely alkaline grades of Lewatit® from LANXESS. The level of organic impurity is also significantly reduced in this process. Silicate can also be removed from a reverse osmosis eluate in the same way.

This enables the best possible conditions to be created for achieving exceptional coating results with dual-component polyurethane-based basecoats and clearcoats. Many high-profile OEMs rely on Lewatit® in their coating lines.

High-profile coatings manufacturers also place very high demands on the water used in the water-based coatings favored today for reasons of environmental protection and emission control. Lewatit® ion exchange resins from LANXESS play a key role in these applications as well.