| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a method for producing a polypropylene resin in-mold expansion molded product using a compressive filling method, in which no welding failure is found near a filling machine-installing region in a molding die. <P>SOLUTION: This method for producing the polypropylene resin in-mold expansion molded product using the compressive filling method is performed by employing polypropylene resin multi-stage expansion particles obtained via following steps. In a first step of manufacturing polypropylene resin expansion particles, the polypropylene resin particles, the base resin of which is the polypropylene resin having a ratio of weight-average molecular weight to number-average molecular weight of≥3.6, are dispersed into a dispersing medium in a pressure vessel, are heated to a temperature higher than the softening temperature of the polypropylene resin particles after addition of an expanding agent which contains carbon dioxide as the expanding agent to impregnate the expanding agent which contains the carbon dioxide into the polypropylene resin particles, and then are discharged from the pressure vessel into reduced ambient pressure by opening an end of the pressure vessel. In a second step of manufacturing the polypropylene resin multi-stage expansion particles, the obtained polypropylene resin expansion particles are moreover expanded. <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
