纤维及薄膜级PET色相b值的影响因素分析  

Analysis of influencial factors on hue b value of fiber-and film-grade PET

作　　者：李华[1] LI Hua(SINOPEC Shanghai Petrochemical Co.,Ltd.,Shanghai 200540)

机构地区：[1]中国石化上海石油化工股份有限公司,上海200540

出　　处：《合成纤维工业》2022年第1期85-89,共5页China Synthetic Fiber Industry

摘　　要：在1 kt/a、10 kt/a及150 kt/a的聚对苯二甲酸乙二醇酯(PET)国产化三釜工艺流程生产装置上,采用直接酯化法连续生产纤维及薄膜级PET切片,分析了原料质量、聚合反应温度、催化剂、调色剂等PET切片色相b值的影响。结果表明:为满足用户对PET切片色相b值达0±1的要求,生产中应控制原料精对苯二甲酸(PTA)中对羧基苯甲醛(4-CBA)含量不大于25 mg/kg,PTA平均粒径(155±15)μm,原料乙二醇(EG)中醛含量不大于8 mg/kg;在聚合反应中,可降低聚合反应温度,减少副产物乙醛的生成,从而降低PET色相b值;使用钛系催化剂生产的PET切片色相b值和L值都较高,可通过降低酯化温度来降低b值,达到使用锑系催化剂生产的切片b值水平;生产中加入调色剂可降低PET切片色相b值,但应按照食品安全国家标准的限制要求选择调色剂及其使用量。Fiber-and film-grade PET chips were continuously produced by direct esterification on 1 kt/a,10 kt/a and 150 kt/a China-made three-kettle polyethylene terephthalate(PET)process production units.The effects of raw material quality,polymerization temperature,catalyst and toner on the hue b value of PET chips were analyzed.The results showed the content of p-carboxybenzaldehyde(4-CBA)in purified terephthalic acid(PTA)should be controlled not higher than 25 mg/kg,the average particle size of PTA be(155±15)μm,and the aldehyde content in raw material ethylene glycol(EG)not higher than 8 mg/kg in order to meet the hue b value of PET chips up to 0±1 required by users;the polymerization temperature reduction can depress the formation of by-product acetaldehyde and thus decrease the hue b value of PET in the polymerization reaction;the b value and L value of PET chips were relatively high in presence of titanium catalyst,and the b value can be reduced to the level in presence of antimony catalyst by reducing the esterification temperature;and the addition of toners during the production can reduce the hue b value of PET chips,but the variety and amount of toners should be decided according to the restrictions of national food safety standards.

关 键 词：聚对苯二甲酸乙二醇酯 色相 b 值 钛系催化剂 调色剂 

分 类 号：TQ323.4[化学工程—合成树脂塑料工业]