| In 2020,the domestic polyolefin market will reach the second peak of capacity expansion in a decade,with an additional capacity of about 4.3 million tons of polypropylene per year.A large number of new plants will put into production,the excessive release of common material products will increase the low-price competition of products.But China's demand for special materials,especially for copolymerization which has a certain gap and a high growth rate.Ningmei Company has a capacity of 1 million tons per year of coal-to-propylene,with a by-product of about 40,000 tons of ethylene per year.The use of polypropylene plant to produce copolymer polypropylene can get higher additional value and better performance,optimize the product structure,expand the market share of high-end products,and improve the efficiency of enterprises.Therefore,this paper studies high melting flow rate and impact copolymer polypropylene production process,product quality,the molecular chain structure and amorphous,the ethylene-propylene rubber phase microstructure and application.Proposed a comprehensive solution through optimizing nuclear agent,adding quantity,production process control indicators,replacing the grain diameter and porosity greater catalyst and putted forward suggestions for follow-up production improvement,form a closed loop improvement.The conclusions are as follows:(1)Evaluate the development prospect,market trend of supply and demand for high melting flow rate and impact copolypropylene used for injection molding,and determine the feasibility of development and production.Investigate the quality requirements of 11 domestic downstream plants for the impact copolymer products.Combining with the national standard of the product,the enterprise standards for the performance indexes of the impact copolymer polypropylene products of Ningmei Company were determined.According to the influence of each reaction parameter on product quality,the control range of each parameter in the production process was determined.(2)Impact copolymer polypropylene was produced by polymerization of two series reactors in Ningmei Company.The ethylene-propylene rubber phase showed an obvious"sea-island structure"distribution,and the impact performance of the product was greatly improved.Under the condition of basically the same bending modulus,the melting flow rate of the produced is increased by 935%and the impact strength at normal temperature is increased by 165%compared with that of the homopolymer general product.However,in respect of the ash content,bending modulus and impact strength of polypropylene,there is still a gap between with the mainstream products in the market which needs to be further improved.(3)The nucleating agent was replaced with 3500 ppm imported organic nucleating agent by3800 ppm talcum powder,and the ash content of the product decreased from 842 mg/kg to 280mg/kg,with a decreasing of 66%.The bending modulus and the nosed impact strength at normal temperature were increased from 1083 MPa and 6.9 KJ/m~2 to about 1195 MPa and 7.7 KJ/m~2respectively,with an increase of 10%and 12%.(4)It was shown that the notch impact strength of the product increased with the increase of EPR phase content,and the increase was obvious when the EPR phase content was 16-17 wt%.The optimal balance between rigidity and toughness was found that the content of EPR phase content was 16?17 wt%.(5)With the replacement of new catalyst with larger particle diameter and porosity,the particle size distribution of the produced powder in the second reactor increased from 78.5%in the range of 0.18?0.425 mm to 91.3%in the range of 0.18?0.85 mm.The polypropylene powder produced has wider particle size distribution and more large diameter particles than the product produced under the original catalyst.On the basis of ensuring the reaction activity,it also solves the problem of excessive output of fine powder,blocking the feeding pipeline and cyclone separator.(6)The index value and measured value of the product in mechanical properties,thermal weight loss performance and other aspects reach the level of similar products.The product was used for the processing of downstream plants,finished product reprocessing,passed the test of freezing impact and other tests,and the actual use is good,can meet the processing requirements.While plastics improve people's lives,"white pollution"and other harmful effects on society and the environment are widely criticized.In this paper,the prospect of more"green"development of single polymer composites,Amorphous Poly-Alpha-Olefin which based on polypropylene substrate was suggested,finally.Comprehensively considering the market supply and demand,the Novolen gas pahase polymerization plant characteristics,Ningmei Company continues to optimize the product structure,in the future,building a solid foundation to steadily expand the market share of high-level products,increase the price of products and enhance the benefits of the enterprise. |
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