聚丙烯薄壁注塑制品白色条带现象解析  

Analysis of White Stripe Phenomenon of Polypropylene Thin-walled Injection Molded Products

作　　者：杨廷杰 任冬雪 程敏 俞越 丛蓉娟 于佩潜 YANG Tingjie;REN Dongxue;CHENG Min;YU Yue;CONG Rongjuan;YU Peiqian(Guoneng Xinjiang Chemical Co.,Ltd.,Urumqi 831400,China;Beijing Institute of Low-carbon Clean Energy,Beijing 102209,China)

机构地区：[1]国能新疆化工有限公司,新疆乌鲁木齐831400 [2]北京低碳清洁能源研究院,北京102209

出　　处：《塑料工业》2024年第11期122-128,共7页China Plastics Industry

基　　金：中国神华煤制油化工有限公司科技创新项目(S930023084)。

摘　　要：为揭示聚丙烯(PP)薄壁注塑制品白色条带现象成因,本文通过分子量分布、化学组成分布、氧化诱导期、结晶行为等表征,对2种典型聚丙烯薄壁注塑料PP-A和PP-B制品进行深入对比分析,前者制品底部以注塑口为中心形成白色条带印记,外观颜色透明度不均匀。通过表征排除了分子链结构和耐热氧老化性能的影响。PP-A制品的白色条带印记在165℃等温处理5 min后逐渐消失,同时表征显示该区域结晶形态不均匀,呈现晶粒的条带状分布,晶粒尺寸较大,而PP-A透明区域和PP-B样片晶粒均匀堆砌无明显区域分布差异,晶粒尺寸较小,确定PP-A制品不同区域外观差异由结晶形态差异导致,推断成核剂分布不均匀是主要影响因素。本文对探究聚丙烯薄壁注塑制品白色条带现象的成因提供了系统的分析方案,为薄壁注塑料的应用和产品升级提供参考。In this paper,to reveal the causes of white strip phenomenon of polypropylene(PP)thin-walled injection molded products,homopolymer polypropylene(PP-A and PP-B)were analyzed in terms of molecular weight distribution,chemical composition distribution,oxidation induction time,and crystallization behaviors.During the thin-walled injection molding process,PP-A formed white strips marked at the bottom of the molded specimen.The white marks radiated from the center outwards,deteriorating the appearances of the products.The effects of molecular chain structures and thermal oxidation were excluded by characterizations.The white marks disappeared after an isothermal treatment process at 165℃for 5 min in an oven.Crystallization behaviors and crystal morphology characterizations show that,inside the area of the white marks of PP-A,the crystal morphology is not uniform,with a banded distribution of large crystal grains.In the transparent areas of PP-A and PP-B,the crystal grains are evenly distributed with small sizes.It is concluded that the differences in the appearances of different regions of PP-A products are caused by the differences in crystal morphologies,likely related to nucleation agents.This paper provides a systematic analysis scheme for exploring the causes of white stripes in polypropylene thin-walled injection molded products,and references for the applications and product upgrading of thin-walled injection plastics.

关 键 词：聚丙烯 薄壁注塑 外观 结晶 

分 类 号：TQ325.14[化学工程—合成树脂塑料工业]