Catalytic system for producing ultrahigh molecular weight polyethylene

Abstract

The invention provides a catalyst system used for preparing ultra-high molecular weight polyethylene. According to the invention, the catalyst system comprises active ingredients, outer electron donors and catalyst promoters; wherein, the total weight of active ingredients of the catalyst based on 100 parts by weight comprises 12.0 to 18.0 parts by weight of magnesium, 4.0 to 8.0 parts by weight of titanium, 1.1 to 11.0 parts by weight of alkoxy group and 55.0 to 75.0 parts by weight of halogens by weight. The method for preparing the active ingredients comprises the steps that: serous fluid of magnesium-alcohol complex is prepared, the serous fluid reacts with the electron donor of (R)nSi, pre-loading titanium reacts with loading titanium. The ultra-high molecular weight polyethylene is prepared by adopting the synergistic effect of the active ingredients, R <1> R <11> Si (OR <111>) <2> and the organoaluminium compound R 3-n ALX n of the invention. The catalyst system of the invention has the advantages of high bulk density, excellent dynamic stability, and the ultra-high molecular weight polyethylene prepared has the advantages of good product form, mean particle distribution and high bulk density; the molecular weight can be adjusted between 2 million and 7 million.

Description

technical field [0001] The invention relates to a catalytic system for the preparation of ultra-high molecular weight polyethylene (UHMWPE). Background technique [0002] Ultra-high molecular weight polyethylene (UHMWPE) is a polyethylene resin with a molecular weight of 1.5 million to 6 million. Because it has a larger molecular weight than ordinary polyethylene, UHMWPE has excellent properties such as impact resistance, wear resistance, self-lubrication, low temperature resistance, and chemical corrosion resistance, and is widely used in machinery, transportation, papermaking, mining, electric power , agriculture, chemical industry, and aviation and other fields. In addition, one of the most important application areas of UHMWPE is ultra-strong polyethylene fiber, which can be used for cables, fishing nets and bulletproof military equipment. To prepare ultra-strong polyethylene fibers, UHMWPE has special requirements. In addition to having a molecular weight higher than ...

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Problems solved by technology

[0004] CN1189486C provides a catalytic system for preparing UHMWPE with high bulk density and good particle shape. The catalyst prepares magnesium-aluminum solution in the presence of alcohol through magnesium halide and aluminum compound, and then adds titanium compound and silicon compound to prepare the catalyst, the preparation of this catalyst is also very cumbersome, and it takes two times of titanium loading to complete the preparation

[0005] CN1034509C provides a kind of preparation method of UHMWPE of high bulk density, and this catalyst is prepared catalyst by Ti (IV) compound is treated with alkylaluminum and reduces Ti, although can prepare the UHMWPE of high bulk density, but catalytic activity is very low, almost no practical value

[0006] CN1746197A provides a catalytic system for preparing UHMWPE with a high bulk density. This catalyst adopts the preparation of a carrier first and then carries titanium to form a catalyst. It can be seen that its catalyst preparation is relatively cumbersome

Although the prepared UHMWPE has a relatively high molecular weight, the average particle size of the polymer particles is not provided, and the catalytic activity is not very high. The catalytic activity is only about 30,000 times when the polymerization time is 4 hours.

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