Unsaturated polyester resins are a possibility. Particular attention must be paid to pretreatment. Because of the relatively susceptible surface, cleaning media must be very mild, eg. based on alcohol. The actual lacquering process is best carried out in a two step process even for mass produced goods.
A primer based on 2-pack epoxide or PU resin lacquers must be applied first and it is important to achieve good adhesion with this. 2-pack PU acrylic coating materials which cure at slightly raised temperatures (up to 80 °C) can be used for the finishing lacquer.
The required light and abrasion resistance of the transparent protective coating should thus be achieved.