PP 7032KN美 孚--一种具有高结晶度、优异刚性以及高抗冲击性能的共聚物树脂，用于注塑成型、挤出成型和热成型场合
PP density is the smallest of all synthetic resins, only0.90-0.91g/cm3, which is about 60% of the density of PVC. Thismeans that more products of the same volume can be produced withthe same weight of raw materials. The tensile strength and rigidityof PP are good, but the impact strength is poor, especially at lowtemperature. In addition, if there is orientation or stress in theforming process, the impact strength will also be significantlyreduced. Although the impact strength is poor, its mechanicalproperties can compete with engineering plastics with higher costin many fields after modification such as filling or strengthening.The surface hardness of PP is lower than that of PE in five kindsof general plastics. When the crystallinity is high, the hardnessincreases correspondingly, but it is still lower than that of PVC,PS, ABS, etc. Among the five general plastics, PP has the best heatresistance. PP plastic products can work for a long time at 100 C,without external force, PP products will not deform when heated to150 C. After using nucleating agent to improve the crystallinestate of PP, its heat resistance can be further improved, and itcan even be used to make utensils for heating food in microwaveoven
未加稳定剂的PP 粉料在室内避光放置4个月也会严重降解，散发出明显的酸味。在PP粉料造粒之前加入0.2%以上的抗氧剂可以有效地防止PP在加工和使用过程中的降解老化。抗氧剂分为游离基链反应终止剂（也称主抗氧剂）和过氧化物分解剂（也称辅抗氧剂）两大类，主、辅两类抗氧剂的合理配合，将会发挥良好的协同效果。PP在离开口模后，如果是在空气中缓慢冷却，就会生成较大的晶粒，制品透明度低。果是在水中急冷（如下吹水冷法制薄膜），PP的分子运动被急速冷冻，不能生成晶体，此时的薄膜就是完全透明的。PP的成型收缩率是比较大的，达到2%以上，远远大于ABS塑料0.5%。
