Solar Loading

We are painting a carbon composite unit with a flat black carc paint #37038. This is the external cover for an optical sight. We are looking for a coating that will provide a dark non reflective color and still limit the solar loading that the unit would absorb.

This is not my working area but please humour me while I speculate. "BLACK" implicitly implies that it will absorb light across a fairly consistent range of the visible frequencies. Unfortunately this usually extends into the Infra-Red region (i.e., heat) which is what I am assuming you mean by the term "solar loading". Unless you can specify a paint that reflects efficiently in the Infra-Red region, I would recommend an undercoat with very low thermal conductivity. A formulation high in aluminium oxide content with a suitable binder would fit the bill. However I am not sure about the adhesion or impact characteristics. Failing all that, you should accept the fact of heating and request a suitable paint.