| 摘要 |
PURPOSE:To efficiently produce a styrene based resin foamed body without causing problem of breakage of ozone layer by blending a styrene based resin with a foaming agent containing a specific fluorinated hydrocarbon under high temperature and high pressure and extruding the blend into low-pressure zone. CONSTITUTION:A styrene based resin is blended with one or more kind forming agents selected from fluorinated hydrocarbons expressed by formula I (a+b+c=3; x+y+z=3; a+x>=1) or formula II (a'+b'=3; m'+n'=2; x'+y'=3; b'+n'+y'>=1), e.g. 3,3-dichloro-1,1,2,2,-pentafluoropropane or 1,3-dichloro-1,1,2,2,3- pentafluoropropane, preferably at a ratio of forming agent of 0.1-50 pts.wt. based on 100 pts.wt. styrene based resin under high temperature and temperature pressure and as necessary other foaming agent (e.g. trichlorofluoromethane) and various kind of additives are added thereto and the blend is extruded into a low-pressure zone to produce the aimed foamed body. |
