NIR & IR Reflection

NIR & IR Reflective Pigments

Something probably everyone has heard once: dark colours absorb heat radiation (IR radiation) - they therefore absorb heat and they heat up more than light colours. Therefore, it tends to be cooler in a white car than in a dark car in summer.

Did you know, however, that there are optically comparable dark colors among them, with some remaining significantly cooler than the others? This property is due to the fact that one group in the non-visible NIR and IR range - i.e. in the near infrared and infrared range, reflect thermal radiation better than others, even if there is a comparable or identical color in the visible wavelength range.

The right pigment ensures the right temperature

It is this very effect that can be used in several ways. By selecting the right pigment in the formulation of dark colours, it can be ensured that the same final colour shade remains cooler. This has a major impact on the temperature behind modern facade looks in applications such as facade paints or finishing plasters. There are ETICS (external thermal insulation composite system) adhesives, for example, that are simply not resistant enough to high temperatures caused by summer sun and dark facade paints.

A smart solution for dark colours: Bayferrox® 303 T instead of carbon blacks in the formulation. Another solution approach: lighter colours adapted to increasingly challenging climatic conditions.

The reflection of this very special iron-manganese mixed oxide pigment BFX 303 T in the NIR range is also used in plastics recycling. NIR scanners are able to receive a sufficiently strong signal with this pigment, i.e. to detect that the plastic is black. However, if plastics without this indicator pigment are only equipped with carbon blacks/soot to color them black, all light emitted by the scanner is absorbed and the black plastic ends up in the unsorted waste.