Hydrochlorofluorocarbon (HCFC) is an ozone-depleting substance that is subject to environmental regulations based onthe Montreal Protocol, and in Republic of Korea, which is regarded as a developing country, its use will be restricted inphase starting in 2013 until finally being prohibited in 2030. HCFC is regulated Based on the Tokyo Protocol, HCFC isa regulated construction material for carbon dioxide reduction with GWP of 1,700~2,400 times that of CO2, with a GWPof 1. Using the CO2 in the heat insulating material in the extrusion process conditions are the first extruder, the polystyreneresin (melting point) and the blowing agent (CO2:Ethanol:HCFC) as interval (Mixing zone) which is the combinedpressure 11.0MPa, temperature 200oC, second within the extruder discharge pressure 6.5 MPa, and determines that it isdesirable to set the temperature of 115oC, the blowing agent mixing ratio (CO2:Ethanol:HCFC), taking into account thestability of the thermal conductivity of 30:20:50%, 25:25:50% is expected to be utilized in the foaming agent.