| 摘要 |
PURPOSE:To improve softness, toughness, resistance to repeated compression, and interparticulate fusibility by infiltrating a volatile foaming agent into particles of a specific PE resin blend and foaming the particles by heating. CONSTITUTION:20-85 pts.wt. low-density PE having a density of 0.917-0.930g/cm<3>, an m.p. of 98-118 deg.C, and an M1 of 0.05-30g/10min is mixed with O-40 pts.wt. high-density PE having a density of 0.940g/cm<3> or higher, an m.p. of 80-130 deg.C, and an MI of 0.05-10g/10min and 0-45 pts.wt. linear low-density PE having a density of 0.915-0.940g/cm<3>, an m.p. of 120-130 deg.C, and an MI of 0.1-30g/10min to obtain particles of the noncrosslinked PE resin blend having a density of 0.92-0.94g/cm<3>. The water content of the particles is regulated to 100-1,000ppm by weight. The resulting particles are impregnated with a volatile foaming agent and then steam-heated at a temp. lower by at least 5 deg.C than the temp. at which the blend melts completely. Thus, the particles are foamed to obtain the objective particles having a degree of expansion of 3-60cm<3>/g, an average cell diameter of 0.07-1.0mm, and a closed cell content of 90% or higher. |
