基于聚乙烯吹塑桶变黄原因的分析研究

Analysis and Research on the Cause of Yellowing of Polyethylene Blow Molding Barrel

食品包装材料的质量安全已成为消费者关注的热点。采用傅里叶变换显微红外光谱仪、气相色谱质谱联用仪和电感耦合等离子体质谱仪分析研究聚乙烯吹塑桶变黄原因,对聚乙烯树脂、第一次成品桶和回用料成品桶进行物质快速筛查,三种样品表面无抗氧剂的析出;三种样品中6种目标重金属含量低,加工吹塑前后重金属含量变化不大;PE树脂中抗氧剂264含量最高,原生料成品桶中抗氧剂264含量减少10%左右,回用料成品桶中抗氧剂264含量减少50%左右,抗氧剂264含量明显减少,研究了抗氧剂264作用机理,认为加工次数和加工温度对样品中抗氧剂264含量减少影响很大,聚乙烯吹塑桶中抗氧剂264含量的减少会导致产品外观产生变黄现象,建议企业合理控制该抗氧剂的用量或更换更稳定的抗氧剂。

The quality and safety of food packaging materials had become the focus of consumers'attention.The yellowing causes of polyethylene(PE)blow moulded barrels were analyzed by Fourier transform micro infrared spectrometer,gas chromatography-mass spectrometry and inductively coupled plasma mass spectrometry.The PE resin,the first finished barrel and the finished barrel of recycled materials were rapid material screened.There is no precipitation of antioxidant on the surface of the three samples.The content of 6 kinds of target heavy metals in the three samples is low,and the content of heavy metals does not change much before and after blow molding.The content of antioxidant 264 in PE resin is the highest,the content of antioxidant 264 in raw material barrel is reduced by about 10%,the content of antioxidant 264 in recycled material barrel is reduced by about 50%,and the content of antioxidant 264 is obviously reduced.The mechanism of action of antioxidant 264 is studied.It is considered that the processing times and processing temperature have a great influence on the reduction of antioxidant 264 in the sample.The decrease in the content of antioxidant 264 in the polyethylene blow molding barrel will cause the appearance of the product to turn yellow.It is suggested that enterprises should control the dosage of the antioxidant reasonably or replace the more stable antioxidant.