Ultraviolet-curable coatings are now the finish of choice to reduce scratching of polycarbonate headlamp and taillight lenses. UV-curable hardcoat materials are typically applied to lenses by spray application or curtain coating. It is critical that these materials be applied at a uniform thickness and cured uniformly to prevent the coating from changing the optical properties of the lens.

UV materials are also applied to automotive reflector bodies to prime and level the plastic prior to the metallizing of the reflector. The UV-curable primer is applied with dip coating, spray or curtain coating. The coating may contain an organic solvent to reduce the viscosity and assist with flow-out.

Reflector Bodies

UV materials are applied to reflector bodies to prime and level the plastic prior to metallizing.

First, compressed air is used to remove particulate contaminants from the surface of the part. Components are then exposed to UV irradiation to increase surface energy and promote adhesion of the UV-curable primer.

Proper surface treatment requires several UV lamps operating at a set power level. Heat management must be carefully controlled, and infrared filtration may be needed depending on the specific type of plastic material. In some applications, a UV topcoat is applied after the part is metallized.