NFC "Nano Functional Coating"

Innovative surface treatment on metal and plastics

The so-called "nanopaints" are usually liquid coating materials consisting in the liquid processing state of particles with a diameter of only a few nanometres. The particles are colloidally dissolved hydroly-sates and partial condensates, mainly of silicon alkoxides. When they cure they create inorganic-organic hybrid networks. Crystalline fillers can also be included that likewise have diameters of only a few nanometres. If these nanoparticles are sufficiently well dispersed the paint films will be very hard and transparent.

Because silane compounds are mainly used in them, nanopaints adhere very well to a range of differ-ent substrates and their mechanical hardness is usually higher than that of comparable convent-ional paint materials based on organic polymers. The thickness of the dry layer in the cured mater-ials is only a few micrometres, typically between 3 and 15 µm. Because of their very good three-dimensional interlacing the layers are very diffusion-proof and thus seal the coated surface perfectly. The layers are frequently hydrophobic and possess "easy to clean" properties. These paints are processed in the same way as conventional liquid paint materials with such pro-cesses as spraying, immersion, or roll-ing, etc. They cure thermally at temperatures between 100°C and 220°C, depending on the material being used, or under UV radiation.

The paints adhere well to practically all surfaces. The best results are achieved on light metals such as aluminium or magnesium, and also on stainless steel. Their properties on iron and steel are not fully comparable with the very good results achievable on light metals. Adherence is good on inorganic surfaces such as glass and ceramics but does require a carefully co-ordinated pre-treatment of the surface that is to be coated. There is not usually any adherence problem on most plastics but they need to be adjusted explicitly to each type of polymer.