| 摘要 |
PURPOSE:To perform treatment under pressure for giving an inner pressure necessary to mold polyolefin prefoamed particles by setting the boosting rate of pressurized gas pressure, the average diameter of prefoamed particles, the temperature of pressurized atmosphere to a specific range. CONSTITUTION:An inner pressure is given in a pressurized gas atmosphere before molding prefoamed particles of polyolefin resin. When the boosting rate of the pressurized gas pressure is given by P(kg/cm<2>/hr), the average diameter of prefoamed particles by R(cm), the temperature of the pressurized atmosphere by T(K), the treatment under pressure is executed by gradually increasing pressure under conditions that PR<=-2.2X10<-5>T<2>+1.3992X10<-2>T-2.189 in 278<T<=348 and P>=0.02. Since the prefoamed particles pressurized and treated in this manner are not shrunk remarkably, no damages, no creases, no flaws occur on the wall of the foamed particles, the prefoamed particles free from internal irregularity and of good quality can be easily obtained. |
