| 摘要 |
PURPOSE:To obtain perfoamed particles having various cell diameters, by releasing polymer particles and a dispersion medium while keeping the pressure in the container equal to or above the vapor pressure of a volatile foaming agent and then keeping the pressure in the container lower than the vapor pressure of the volatile foaming agent. CONSTITUTION:10-40pts.wt. volatile foaming agent are incorporated into 100pts.wt. copolymer particles, and the mixture is dispersed into a dispersion medium such as water, ethylene glycol, etc. After the dispersion is heated to 90-170 deg.C, by opening one end of the container the polymer particles and the dispersion medium are simultaneously released while keeping the pressure in the container equal to or above the varpor pressure of a volatile foaming agent. Then further the polymer particles and the dispersion medium are released while keeping the pressure in the container lower than the vapor pressure of the volatile foaming agent. Therefore prefoamed particles having various cell diameters can be obtained. As the polymer particles, can be used particles of olefinic polymers, vinyl chloride polymer, etc. |
