摘要 |
PURPOSE:To manufacture easily a high-magnification foam having a microscopic and uniform bubbles, by a method wherein extrusion foaming is performed by making use of a pellet obtained by kneading polyphenylene ether and polystyrene. CONSTITUTION:After kneading of a pellet obtained by kneading 40-90 pts.wt. polyphenylene ether and 60-110 pts.wt. polystyrene with an extruding machine and a foaming agent under a high temperature and high pressure, the same is extruded in a low-pressure zone. In this instance, when the polyphenylene either is less than 40 pts.wt., it is not only that heat resistance becomes insufficient but also that in the case where both are made into the pellets by kneading them, the pellets become cloudy due to insufficient melting of the polyphenylene ether and when extrusion foaming is performed by making use of the pellet, bubble irregularity is generated within a foam. On the one hand, when the polyphenylene either exceeds 90 pts.wt., gelation can not be performed by an ordinary extruding machine due to an insufficient temperature rise or overloading and pelleting becomes very hard. |