车用耐光老化抗冲击聚丙烯树脂工业化开发

Industrialization of impact polypropylene for vehicles with light-aging-resistant

以工业化生产的聚丙烯(PP)粉料和自制的复配助剂包为原料,利用双螺杆挤出机制备了车用耐光老化高熔体流动速率PP树脂,研究了氙灯加速老化暴晒对PP树脂表面特性影响以及老化前后PP树脂残留挥发性有机物(VOC)的种类和含量。实验结果表明,常规抗冲击PP树脂耐光老化性能较差,加速老化暴晒5周期后,老化降解严重,颜色、外观、光泽度及色牢度等降低明显,残留VOC种类增多,且多为含氧基团类小分子化合物。改性后的PP树脂抗冲击性能和氧化诱导期(OIT)有一定提高,其他常规性能基本无变化,加速老化暴晒5周期后,树脂颜色仅略有变化,色牢度保持在4~5级,残留的VOC种类无明显增多,且无含氧基团类小分子化合物。氙灯加速老化暴晒后改性PP和常规PP中VOC种类和含量均不相同,大多数VOC有毒有害,但改性PP树脂中残留的烃类VOC多由聚合过程中低聚物以及加工过程中降解引起;常规PP的含氧基团类VOC主要由PP树脂在光照过程中氧化降解导致,是引起酸味等刺激性气味的主要原因。首次工业化生产的新牌号PPB-MW30-GH具有优异的耐光老化性能,符合汽车内饰件材料未来绿色环保发展的理念。

The commercialpoly propylene(PP)powder and the self-made composite additive package were used as raw materials to prepare the PP resin for vehicles with both the light-agingresistant and the high melt flow rate using the twin screw extruder.The effects of accelerated Xenon lamp aging exposure on surface characteristics of PP resin as well as the type and content of residual volatile organic compounds(VOC)of PP resin before and after aging were studied.The result shows that the conventional impact-resistant PP resin has bad light-aging resistance,after 5 cycles of the accelerated aging exposure,the PP was degraded seriously,leading to the obviously changed colour,appearance,gloss and colour fastness,as well as the increased amount of residual VOC and they are mostly small molecule compounds containing oxygen groups.After modification,the impact resistance and oxidation induction period(OIT)of PP resin have been improved to a certain extent,and other conventional properties have not changed.After 5 cycles of accelerated aging exposure,the colour of the modified PP resin changed only slightly,and the colour fastness was maintained at 4 to 5 levels.The types of VOCs remaining in PP did not increase significantly,and there are no small molecule compounds containing oxygen groups.The types and contents of VOCs in modified PP after accelerated aging exposure and conventional PP are different,and most VOCs are poisonous and harmful.The residual hydrocarbon VOCs in modified PP resins are mostly caused by oligomers during the polymerization process and degradation during processing;the VOCs in conventional PP containing oxygen groups are mainly caused by the oxidative degradation of PP resins in the light process,which is the main cause of pungent odors.The new grade PPB-MW30-GH produced for the first time in industrial production has excellent light-aging resistance,which is in line with the concept of the future green environmental protection development of automotive interior materials.