| 摘要 |
PURPOSE:To improve thermal insulation and cushioning properties by melting a thermoplastic resin compsn. contg. a specified amt. of a syndiotactic PP in an extruder, forcing a low-boiling substance into the melt, and extruding it into the air under cooling. CONSTITUTION:At least 50wt.% syndiotactic PP which has an intrinsic viscosity (135 deg.C, a tetralin soln.) of 0.1-10.0 and comprises a propylene homopolymer having a syndiotactic pentad fraction of at least 0.6 or a propylene-alpha-olefin copolymer having a peak intensity around 20.2ppm in 13C-NMR measured using a 1,2,4-trichlorobenzene soln. of at least 0.3 times the peak intensity assignable to all the methyl groups of propylene units is mixed with another thermoplastic resin, if necessary, giving a thermoplastic resin compsn. After the compsn. is melted in an extruder, a low-boiling substance as a blowing agent is forced into the melt, which is then extruded under cooling through a die at the end of the extruder into the air, thus giving the title sheet. |
