The Research And Development On High-density Polyethylene Film Resin Product

The domestic demand for HDPE packing material is huge and the trend of marketing demand for film grade HDPE resin is escalating. Nevertheless, there is some gap between the domestic and developed countries in terms of product quality. Therefore, a series of measures should be taken to accelerate the course of research and development and production of film grade HDPE resin, increase the productivity and enhance the performance as well. Considering the fact that the film product is scant on market, this thesis aims at new HDPE film product referring to imported technology from one certain existing plant. The structure of first generation product was represented and demonstrated to be incompliance with the bimodality character. The second generation and final product was developed after modifying the process and compared with domestic and overseas product regarding its structure and performance, which provides evidence for the further optimization of plant process.By means of high temperature gel chromatography test, the molecular weight of the product is in bimodality distribution with wide range, but the difference of the molecular weight between two peaks is minor, the molecular weight is centrally distributed. The crystallinity was tested via DCS method and approved to be high with good mechanical properties, high strength, and a little baddish transparency. The processing rheological properties of the melting product is tested as well, the extrusion pressure of the new developed product is similar with that of other HDPE in the low shear rate area and the pressure goes up gradually when the shear rate ascends. The pressure will fluctuate apparently in the high shear rate area which manifests that the processing stability is not satisfied. The performance of the product was researched after it was produced into film by film tensile strength test, breaking elongation test and T-tensile test. The result indicates that the structure of the material may vary remarkably by virtue of diverse polymerizing process despite being same HDPE product, which will consequently impact the processing rheological behavior and mechanical properties of the product. In summary, each performance objective of the new developed product is compatible with requirement, however, there is still some disparity in terms of processing property in contrast with other company's product. Hence, the process parameter should be appropriately optimized and improved to better suffice the client's desire.