| 摘要 |
A novel foam composed of closed cells having a specific tensile strength of 150 kg/cm2 or more, a compression recovery of 80% or more and a heat shrinkage of 50% or less, a variation in thickness of foam of less than 50%, a corrugation value of less than 100% and a surface smoothness of less than 2 mm, an average cell diameter of 0.05-3 mm, said foam having a foam density of 0.007-0.10 g/cm3, a variation in thickness of cell wall film of +/-30% or less and a variation factor of cell diameter of 70% or less, obtained by foaming a composition consisting essentially of 100 parts by weight of a substantially non-crosslinked polyethylene having a density of 0.935 g/cm3 or more and a melting point of 117 DEG C. or more, 0.05-10 parts by weight of a foaming decelerant having the capability of prolonging the foaming time by at least one second as compared with the absence of the foaming decelerant, as measured by a glass tube blowing test method, and 0.001-5 parts by weight of a nucleating agent. The resulting foam has excellent mechanical properties and heat-resistance and has a good appearance. |
