【摘要】 从聚丙烯挤出发泡的加工设备包括挤出机的类型、发泡机头的设计、发泡剂的注入和计量控制以及聚丙烯挤出发泡的成型工艺包括螺杆转速、压力降和压力降速率、成核剂的分散、发泡机头的温度等系统介绍了聚丙烯挤出发泡中的一些关键技术。目前的研究表明:采用双螺杆挤出机进行挤出发泡时需要考虑发泡剂逃逸和压力的升高与稳定;可以通过改变机头的形状和尺寸获得不同的压力降和压力降速率,从而控制挤出发泡的成核速率。提高螺杆转速、增加压力降和压力降速率有利于优质发泡材料的获得;优选适宜的发泡机头温度可以抑制气体逃逸,提高发泡倍率,获得更低密度的聚丙烯发泡材料。更多还原

【Abstract】 The key technologies used in the extrusion of polypropylene foam were introduced based on the equipments and foaming parameters, with focus on the extruder kinds, design of foaming die, injection and metering of blowing agent, screw rotating speed, pressure drop and pressure drop rate, nucleatant distribution and foaming die temperature. The research results showed that the blowing agent escaping, the pressure stabilization and increase should be done when the twin-screw extruder was used. The cell nucleating rate was controlled by the pressure drop and pressure drop rate by changing the geometry and size of the foaming die. PP foam with high quality was made with the higher screw speed, higher pressure drop and pressure drop rate. To improve the volume expansion rate, lower the density of PP foam, gas escaping should be avoided by selecting the appropriate die temperature.更多还原