LDPE/LLDPE/EVA复合膜的热封性能优化

Orthogonal Experimental Design Optimization of Heat-Sealing Performance of LDPE/LLDPE/EVA Composite Films

采用正交实验设计方法研究了低密度聚乙烯(LDPE)/线性低密度聚乙烯(LLDPE)/乙烯-醋酸乙烯共聚物(EVA)复合膜的热封性能,系统探讨了复合膜热封强度与热封温度、热封时间、热封压力和EVA添加量等工艺参数的依赖程度。结果表明,热封温度对LDPE/LLDPE/EVA复合膜热封强度的影响最大,其次为EVA含量,二者均显著高于其他2个因素的影响程度。薄膜热封强度随着EVA含量的增加出现先上升后减小的趋势,当EVA用量为5.0%时出现最大值。但热封时间和热封压力对复合膜热封强度的影响较小。经分析可知,最佳的薄膜热封条件是EVA含量为5.0%、热封时间为2.5 s、热封温度为110℃和热封压力为300 N,最优条件下的热封强度高达18.72 N/15mm。

An orthogonal experimental design method was used to study the heat sealing performance of low density polyethylene （LDPE）/linear low density polyethylene （LLDPE）/ethylene/vinyl acetate copolymer （EVA） composite films, and the dependences of the film heat-sealing strength on EVA content, heat-sealing temperature, time, and pressure were diseussed. Experimental results showed that the heat-sealing tmnperature had the greatest effect on the heat-sealing strength of LDPE/LLDPE/EVA composite films, followed by the EVA Content, both far higher than the other factors. The film heat- sealing strength was seen to increase at the start but then decrease as the EVA content increased and it reached the maximum when the EVA content was 5.0%. The heat-sealing time and pressure were both seen to not considerably influence the film heat-sealing strength. Analysis results released that the optimized conditions for the film heat sealing had been determined, when the EVA content was 5.0% , the heat sealing time was 2.5 s, heat sealing temperature was 110 ℃ and heat sealing pressure was 300 N. Under such optimal conditions, the heat sealing strength was as high as 18.72 N/15mm.