UV激光刻蚀BOPP薄膜包装特性研究

Packaging Characteristics of UV Laser Pretreated BOPP Film

目的研究UV激光刻蚀双向拉伸聚丙烯(BOPP)薄膜后分子结构的变化,分析UV激光刻蚀对薄膜结构及透氧、透湿和力学性能等包装性能的影响,以便更好应用于食品包装领域。方法通过激光扫描显微镜分析、红外光谱分析和拉曼光谱分析,研究不同刻蚀深度薄膜表面形貌及内部分子结构变化。结果红外光谱无变化,说明无新的非极性键产生,拉曼光谱出现荧光,在1613 cm-1处的特征峰说明C=C双键出现;激光刻蚀处理可以提高薄膜透氧和透湿性能,且随刻蚀深度增加而增加,薄膜正向氧气透过性大于反向,反向水蒸气透过性大于正向;薄膜机械性能下降,刻蚀线方向与拉伸方向垂直时,其力学性能下降要大于刻蚀线方向与拉伸方向平行。结论在使用UV激光刻蚀薄膜进行包装设计时须考虑薄膜方向以及刻蚀线方向。

Objective To study the changes in the molecular structure of the biaxially oriented polypropylene（BOPP）films after UV laser etching, and to analyze the effects of laser etching on the film structure and packaging performance such as oxygen permeability, moisture and mechanical properties, targeted for better applications in food packaging. Methods The surface morphology of the film and the changes in the internal molecular structure at different etching depth were studied by laser scanning microscopy, infrared spectroscopy and Raman spectroscopy. Results The unchanged infrared spectra excluded the generation of a new non-polar bond, while appearance of the fluorescence characteristic peak at 1613cm-1in Raman spectroscopy indicated the occurrence of C=C double bond. Laser etching process could improve the oxygen permeability and water vapor permeability of the film, and the performance was improved with the increasing etching depth.The oxygen permeability of the film was greater in the forward direction than in the reverse direction, while it was the opposite for the water vapor permeability. The mechanical performance of the film was decreased, when the etching line direction was perpendicular to the stretching direction, the decrement was larger as compared to the value measured when the tensile direction was parallel to the etching line direction. Conclusion When UV laser pretreated films are used for packaging design, the direction of the film and the etching line should be considered.