PURPOSE: To obtain a crosslinked synthetic resin foam having excellent resistance to heat and low-temperature impact and high-temperature processability and suitable for use as an automobile trim and a substrate for pressure-sensitive adhesive type, by crosslinking and expanding an expandable olefin resin compsn.
CONSTITUTION: A propylene/ethylene random block copolymer having an ethylene component content of 16W70wt% as resin component, a block coefficient (absorbance ratio of absorptions at 720cm -1 and 731cm -1 assignable to ethylene component in an infrared absorption spectrum) of 0.8 or above, a degree of isotacticity of 40% or above, a melt flow rate of 0.1W30 and a high-temperature side m.p. of 130W165°C is used (an appropriate amount of an olefin polymer such as low-density or high-density polyethylene may be used together). An expandable resin compsn. consisting of said copolymer, a blowing agent, a crosslinking agent and other additives are crosslinked and expanded by any of conventional methods to obtain the purpose crosslinked synthetic resin foam.