I'm looking for data on the thermal conductivity of the solder mask, including is it the same for all the colours. The JLCPCB specification page lists the thickness as 10 to 15um, and the dielectric constant as 3.8, but doesn't give a thermal resistance (often given as °C/W/sq cm).
I have to dissipate several Watts through the backside of the PCB and would rather not have the copper exposed as it is at 48 volts so would be legal but best to be covered.
