BHL催化剂在MarTECH™ ADL工艺装置上制备单峰聚乙烯树脂OA

Unimodal polyethylene resins are widely used in injection-molding,fiber,and other specialty applications because of their concentrated molecular weight distribution,high structural uniformity,and stable processing and mechanical properties.The MarTECH™ advanced dual-loop(ADL)slurry process is widely used for industrial high-density polyethylene production because of its high production efficiency,flexible grade switching capability,and suitability for continuous large-scale operation.However,the production of unimodal polyethylene grades in this process has long relied on imported catalysts,and further improvement is still required in resin quality and comprehensive product performance.To promote the localization and upgrading of catalysts for the ADL process,the BHL catalyst developed by Sinopec(Beijing)Research Institute of Chemical Industry Co.,Ltd.was applied in an industrial MarTECH™ ADL process unit to produce two unimodal polyethylene grades,including injection-molding grade HMN6080 and fiber grade HMN55180.The performance of the BHL catalyst was systematically compared with that of a reference catalyst under corresponding industrial production conditions.The relationships among catalyst characteristics,process parameter control,resin molecular structure,and final product properties were investigated by SEM,GPC,DSC,rheological measurements,and mechanical property tests.The results show that the BHL catalyst exhibits regular particle morphology,high catalytic activity,and good copolymerization capability.The BHL catalyst can be well matched with the dual-loop slurry polymerization process and enables the stable production of unimodal polyethylene resins with different melt flow rates and densities.Compared with the reference catalyst,the BHL catalyst endows the resins with a narrower molecular weight distribution and better unimodal characteristics,which indicates improved control of polymer chain growth under ADL process conditions.The DSC results show that the BHL resins have higher crystallinity and melting enthalpy,suggesting better chain regularity and more favorable crystallization behavior.In addition,for HMN6080 and HMN55180,the wax content of the BHL resins is reduced by 3.9%and 15.5%,which indicates a decrease in low-molecular-weight fractions and contributes to improved processing stability.Rheological analysis further confirms that the resins produced wtih BHL catalyst exhibit more stable melt behavior,and mechanical testing shows that the impact properties of HMN6080 and HMN55180 are improved by 10.5%and 6.7%,respectively.These results demonstrate that the BHL catalyst has good adaptability and comprehensive performance advantages in the MarTECH™ ADL process.This work provides technical support for the industrial production of high-performance unimodal polyethylene resins and offers a practical route for the substitution and upgrading of imported catalysts in large-scale polyethylene production.