At the 2021 Petroleum deep Processing and Green Catalysis Technology webinar held recently, many experts and scholars said that the original innovation to achieve "innovative and unique", As well as the breakthrough of high-performance olefin polymerization catalyst and new polyolefin material technology, will become the only way for China's polyolefin industry to enter a new stage of development.

POE production technology is expected to break through

The "Industrial Structure Adjustment Guidance Catalog" issued by the National Development and Reform Commission in 2019 encourages the development of polyolefin elastomer (POE) and other materials. POE global annual consumption has been close to 1.2 million tons, China's annual market demand has more than 200,000 tons, is still increasing year by year at a growth rate of about 10%.

Tianjin University of Science and Technology Professor Jiang Tao team members introduced, POE synthesis technology mainly uses solution polymerization process, foreign catalysts, polymerization process field has a large number of patents, related core technology is not transferred to foreign countries. Chinese universities and research institutes have carried out relevant research on POE synthesis technology, and developed metallocene catalysts and non-organometalene catalysts with high copolymerization properties, but the last kilometer path to achieve engineering has not yet been opened.

POE key technical problem is efficient independent catalyst, Jiang Tao research group from the catalyst screening, ethylene / 1-octene copolymerization, ethylene /α -olefin copolymerization, POE continuous polymerization and other aspects of the key to simplify the traditional process route, reduce the plant investment and production costs, the prepared POE test sample has good toughness and elastic recovery performance, elongation at break up to 927%.

Professor Xu Sheng of East China University of Science and Technology believes that in POE catalysts, the structural innovation of CGC type catalysts is more difficult, but there is still room. Double center rigor Flexible amphigamous ligand structures may offer unexpected surprises. Xu's team found that they could replace metals with organic ligands. Halogen in halogen bond is an effective means to improve the insertion rate of octene. The non-cyclopentadiene structure catalyst has the characteristics of high temperature resistance and high octene insertion rate, and the industrialization prospect is broad.

COC/COP localization still needs time

Cyclic olefin copolymer (COC) and cyclic olefin polymer (COP) are a new type of high value-added thermoplastic engineering plastics. China is the world's largest COC/COP market, but the technology in this field is basically blank at present, and the COC/COP materials of high-end manufacturing industries such as mobile phones, display screens and optical devices are monopolized by foreign enterprises.

At present, there are two main processes for the production of COC and COP, namely, ring-opening shift polymerization process and metallocene catalytic addition polymerization process; The key technical problems include synthesis technology of cycloolefin monomer, high efficiency and high temperature resistance metallocene catalyst, deep purification technology of copolymerization products, localization of cocatalyst, chain structure and relative molecular mass control.

The metallocene catalyst designed and synthesized by Jiang Tao's team has good high temperature resistance. By constructing and optimizing the structure of metallocene catalyst, they reduce the preparation cost of metallocene catalyst and reduce the production cost of COC; To carry out the optimization of polymerization process conditions and the development of continuous polymerization process, batch preparation of COC copolymer processing application research.

Professor Li Xiaofang of Beijing Institute of Technology believes that the production process of COC is more complex, and the synthesis of cycloolefin monomer is difficult, and only a few enterprises in the world have the technology and production process to reach the level of large-scale mass production. Some enterprises and research institutions in China are still in the pilot stage, and the talent reserve and process technology still need to be improved in large-scale mass production. They have developed a series of rare earth catalysts to achieve polymerization/copolymerization of a variety of cycloolefin, and obtained COC materials with high activity, high cycloolefin insertion rate and high selectivity.

Metallocene polyolefin challenges remain

China's metallocene polyolefin industry started more than 20 years later than foreign countries, but the development rate in the past 10 years is encouraging. At present, a hundred-ton polyethylene metallocene catalyst unit has been put into production. Sinopec has independently developed metallocene polyethylene catalysts, and petrochina has independently developed metallocene polypropylene and metallocene rubber catalyst technologies. Daqing Petrochemical and other seven enterprises have achieved mass production of metallocene polyethylene, and Maoming Petrochemical, Yanshan Petrochemical and Lanzhou Petrochemical have respectively produced metallocene polypropylene products.

The rising space of China's metallocene polyolefin industry is very large, the market demand of high-end metallocene polyolefin products is very strong, and the technology accumulation and hardware and software conditions of petrochina, Sinopec and Yantai Wanhua in the industrialization of metallocene polyolefin have been basically mature. But also to the metallocene polyolefin industry original technology breakthrough to bring driving force.

However, there are still many challenges to achieve major original breakthroughs in polyolefin technology. Xin Shihuuan, distinguished professor of Northeast Petroleum University, said that on the one hand, the activator/cocatalyst of metallocene catalyst and the carrier of metallocene catalyst are currently dependent on imports, which can meet the raw material purification and impurity control indicators and rapid detection technology and implementation standards of metallocene catalyst polymerization technology are lacking; On the other hand, China's metallocene catalysts lack scientific problem-oriented, systematic theoretical system mining and research, catalyst structure design and catalytic polymerization theoretical calculation ability is seriously insufficient.

Therefore, he suggested the establishment of a special research fund for polyolefin catalysts with single active center at the national level to carry out long-term research on key equipment, computing capacity, digitalization and intelligence; To establish a polyolefin material innovation consortium to solve the problem of high-end polyolefin external dependence as soon as possible; Organize a team of interdisciplinary experts to conduct in-depth research on the whole industrial chain from the structural design of polyolefin catalysts with single active center to the recycling and utilization of waste polymers.