Innovene工艺丙烯-乙烯无规共聚物块料结构表征与结块原因剖析

Structural characterization and cause analysis of propylene-ethylene random copolymer block in Innovene process

利用GPC、升温淋洗组分分析、DSC、ICP-AES等方法对Innovene工艺装置生产的丙烯-乙烯无规共聚物块料及粉料进行了测试与表征。实验结果表明,与粉料相比,块料中丙烯组分含量高,而乙烯组分含量低;块料的分子量分布比粉料的宽,熔点总体上高于粉料,催化剂残留量低于粉料。块料内部的乙烯组分含量低于块料表面,熔点和结晶温度均比块料表面高,催化剂残留量比块料表面更低。实际生产工况中,块料主要产生在第Ⅱ反应器一区和二区搅拌桨叶周围。应尽可能减小第Ⅰ反应器出料树脂颗粒与第Ⅱ反应器一区丙烯/乙烯混合气之间的温差;或尽可能降低第Ⅱ反应器一区温度,使其接近第Ⅰ反应器出料树脂颗粒温度,从而缓解或防止结块。

The block of propylene-ethylene random copolymers formed in Innovene process device and its corresponding granular powder were tested and characterized by GPC,temperature rising elution fractionation analysis,DSC and ICP-AES.The experimental results show that compared to granular powders,the block samples possess a higher content of propylene component,a wider molecular weight distribution,and a higher melting point(Tm),however a lower content of ethylene component,and a lower residual amount of catalyst.The content of ethylene component and residual amount of catalyst inside the block are lower than those on the surface of the block,while the Tm and crystallization temperature of the interior sample are higher than that in the surface one.In actual operation conditions,the blocks are often generated around the stirring paddles in the 1st zone and the 2nd zone of the reactorⅡ.Therefore,the differential temperature between the resin particles discharged from the reactorⅠand the propylene/ethylene mixture in the 1st zone of the reactorⅡshould be decreased as much as possible.Alternatively,the temperature of the 1st zone of the reactorⅡshould be reduced as much as possible to close to the temperature of the resin particles discharged from the reactorⅠ,in order to alleviate or prevent blocking.