摘要
双向拉伸聚丙烯薄膜(BOPP)具有优异的光学以及力学性能,在包装领域具有重要的用途.然而,在温度较高的南方天气下,BOPP薄膜容易发生收缩,产生褶皱缺陷,严重的甚至导致产品变形.BOPP薄膜的后收缩严重影响了产品的气密性、美观度、成本以及销量.针对该现象,本文结合差示扫描量热仪、广角X射线衍射系统、光泽度仪、雾度仪、摩擦仪、万能拉伸试验机、热封仪、测厚仪等多种技术表征手段研究了BOPP薄膜在 40～80℃下退火过程中的结构与性能变化.研究结果表明,退火时间越长、退火温度越高,BOPP薄膜的收缩率越大,退火后的结晶度和晶体取向程度增加.BOPP薄膜的厚度、雾度、摩擦系数、光泽度、热封强度没有发生太大的变化,收缩率减小,拉伸强度变大.该研究为改善BOPP薄膜的后收缩提供了理论指导.
Abstract
Biaxially oriented polypropylene(BOPP)films with excellent optical and mechanical properties play an important role in the packaging field.However,in the southern weather with high temperature,BOPP films tend to shrink,resulting in fold defects and product deformations.The post-shrinkage of BOPP films strongly affects the gas emission,beauty,cost and the sales.The evolutions of structures and properties of BOPP films during the annealing at 40-80 ℃ were systematically investigated by differential scanning calorimetry,wide-angle X-ray diffraction,gloss meter,tribometer,haze meter,tensile testing machine,heat sealer,and thickness gauge.The results show that the longer the annealing time and the higher the annealing temperature,the larger the shrinkage rate of BOPP films,the higher the crystallinity and crystal orientation after annealing.Meanwhile,the thickness,haze,friction coefficient,gloss,and heat seal strength change little,while the shrinkage rate decreases and tensile strength increases.This study provides theoretical guidance for improving the post-shrinkage of BOPP films.
维普
万方数据