二醋酸纤维素塑料生产中挥发分的脱除与利用

Removal and Utilization of Volatiles in Production of Cellulose Diacetate Plastics

分别研究了二醋酸纤维素塑料水分、增塑剂吸收量及生产过程中螺杆转速、喂料量、螺杆组合对脱挥效率的影响。结果表明,水分作为助脱挥剂,有利于脱挥;增塑剂吸收量高,不利于脱挥;高螺杆转速、低喂料量、排气口前高屏障型螺纹元件均有利于脱挥;挥发分的有效脱除可改善产品通透度和热稳定性;挥发分中60%以上为邻苯二甲酸二乙酯(DEP)成分;通过设计冷凝系统,实现了挥发分中增塑剂的分离,从而实现了DEP的回收利用。

The effects of the moisture content and the plasticizer absorption rate on the devolatilization efficiency of cellulose diacetate were investigated,and the influences from the screw speed,feeding amount and screw configuration were also analyzed.The results indicated that water as a devolatilization promoter facilitated devolatilization.High plasticizer absorption was disadvantage for devolatilization.However,high screw speed,low feed rate and the use of high-barrier threaded element in front of the exhaust port were advantageous for devolatilization.The devolatilization can improve the transparency and heat stability of the products of cellulose diacetate.The composition analysis indicated that more than 60%of volatiles were diethyl phthalate.The condensation system was designed to perform the separation of plasticizer from volatiles,realizing the recovery and utilization of diethyl phthalate.