Risho has low modulus + high thermal conductive material which can prevent solder joint crack. With MCPCB, we may have a CTE mismatch between big components and aluminum plates which causes solder joint crack on the solder pad. This material can absorb the stress caused by this CTE mismatch and can prevent solder joint crack.
2W/mK with Ultra Low Modulus (0.08 GPa) Al-Base MCPCB and RCC
3W/mK with Low Modulus (2.4 GPa) Al-Base CCL, Bonding Sheet, RCC and CCL