Catalysts Of Ethoxymagnesium Supported Zieglger-natta And Preliminary Study Of Ethyhene Prepolymerization

This study is aimed at promoting the development of domestic ethoxymagnesiμm type polyethylene catalyst,With ethoxymagnesiμm support and catalyst preparation technology as a breakthrough. In the case of ethoxymagnesiμm carriers, it has been disclosed that large particles of ethoxymagnesiμm can be prepared by the combination of dioxysil and decane, While a small amount of silica and decane can improve the overall performance of small particle size ethoxymagnesiμm particles,Pentaerythritol can effectively improve the bulk density and flow properties of small particle size ethoxymagnesiμm particles; In the catalyst preparation technology, it has been disclosed that the ethoxymagnesium-supported polyethylene catalyst catalyzes the polymerization of ethylene under.the condition of industrial small test,which is substantially non-active, but after the prepolymerization of the ethylene, at 28/45 (hydrogen pressure: (g PE/g Cat)times, the catalytic efficiency of the catalyst can be increased to 17,000(g PE/g Cat) by adding the multi-element silane-based electron donor under the condition of hydrogen pressure of 0.28 MPa and ethylene pressure of 0.45 MPa.The best preparation conditions:Large particles of ethoxymagnesiμm Preparation: m(Mg): V(CH3CH2OH): m (silica):V(decane) = 1g: 30 mL: 0.2g: 10 mL, Bulk density of ethoxymagnesiμm, The flow inclination value tanθ, particle size d(50)and particle size distribution index were 3.42 g·cm-3, 0.719,158.9 μm, 1.96, The ethoxymagnesiμm particles d(0.5) can be prepared up to 240μm after mechanical stirring.Small particle size ethoxymagnesiμm Preparation: m(Mg): V(CH3CH2OH): m (silica), V(decane) = 1 g: 20 mL: 0.05 g: 2.5 mL,Under magnetic stirring rate 1000r / min, three feeding conditions, It can obtain ethoxymagnesiμm particles having a bulk density of 0.469 g-cm-3,a flow inclination tanθ of 0.615 and a particle diameter d (0.5) = 26.9 μm.Catalyst preparation: When m(Small particle size ethoxy magnesiμm): V (TiCl4) = 1g: 10mL, We can abtain spherical catalyst with the d (0.5)=26.1, dropping titaniμm rate of 0.5 mL·(support(g)·h)-1,After prepolymerization multiples of 0.2 times (g PE/g Cat), at 28/45, the catalytic efficiency may be increased from 1,250 times to 17,185 times,The polymer had a melt index (5 kg) of 11.7 g·(10 min)-1, The point of polymer melting is 133.75 ℃, crystallinity is 77.8%, a number average molecular weight is 49000, a recombination molecular weight is 2.83×105 and molecular weight distribution is 6.9.This paper provides the basis for the preparation technology of catalyst and catalyst preparation for ethoxymagnesium type catalyst, and is prepared for the localization of ethoxymagnesium supported Ziegler-Natta catalyst.