Provided is an olefin polymerization catalyst carrier with a general structure formula of Mg(OR.sup.I).sub.n(OR.sup.II).sub.2-n, wherein: 0≦n≦2, and R.sup.I and R.sup.II can be the same or different and are each independently selected from a C.sub.1-C.sub.20 hydrocarbon group. In the X-ray diffraction pattern of the catalyst carrier, there are a set of diffraction peaks in the range of a 2θ diffraction angle of 5°-15°, and the set of diffraction peaks contain 1-4 main diffraction peaks. Also disclosed is an olefin polymerization solid catalyst component which is prepared from the carrier Mg(OR.sup.I).sub.n(OR.sup.II).sub.2-n, a titanium compound, and at least one electron donor compound. In addition, also disclosed is an olefin polymerization catalyst containing the solid catalyst component, at least one organic aluminum compound, and optionally, an external electron donor compound.

A method of making an olefin polymerization catalyst carrier with a general structure formula of Mg(OR.sup.I).sub.n(OR.sup.II).sub.2-n, wherein: 0≤n≤2, and R.sup.I and R.sup.II can be the same or different and are each independently selected from a C.sub.1-C.sub.20 hydrocarbon group by reacting an alcohol with a metal magnesium powder under the protection of nitrogen in the presence of a halogen or a halogen-containing compound to obtain a first product, and subjecting the product to a treatment pressure of from 0.2 to 5.0 MPa at a treatment temperature of from 80 to 200° C. for a duration of between 2 minutes and 6 hours. Also provided is a method of making an olefin polymerization solid catalyst component which includes the catalyst carrier, a titanium compound, and at least one electron donor compound.

According to the present invention, there is provided a method for preparing low molecular weight amorphous polypropylene. In contrast to the prior art in which amorphous polypropylene is prepared by injecting an internal donor and an external donor upon preparing a primary catalyst, the present invention enables easier preparation of low molecular weight amorphous polypropylene and a copolymer thereof by simply mixing a primary catalyst with an alkylaluminum-based co-catalyst without injecting an internal donor, upon preparing a primary catalyst, and an external donor, upon polymerization. According to the present invention, the primary catalyst has superior reactivity with hydrogen, as chain transfer agent, allowing for preparation of low molecular weight amorphous polypropylene even under low hydrogen pressures and low-pressure driving conditions.

A method of making an olefin polymerization catalyst carrier with a general structure formula of Mg(OR.sup.I).sub.n(OR.sup.II).sub.2-n, wherein: 0n2, and R.sup.I and R.sup.II can be the same or different and are each independently selected from a C.sub.1-C.sub.20 hydrocarbon group by reacting an alcohol with a metal magnesium powder under the protection of nitrogen in the presence of a halogen or a halogen-containing compound to obtain a first product, and subjecting the product to a treatment pressure of from 0.2 to 5.0 MPa at a treatment temperature of from 80 to 200 C. for a duration of between 2 minutes and 6 hours. Also provided is a method of making an olefin polymerization solid catalyst component which includes the catalyst carrier, a titanium compound, and at least one electron donor compound.

According to the present invention, there is provided a method for preparing low molecular weight amorphous polypropylene. In contrast to the prior art in which amorphous polypropylene is prepared by injecting an internal donor and an external donor upon preparing a primary catalyst, the present invention enables easier preparation of low molecular weight amorphous polypropylene and a copolymer thereof by simply mixing a primary catalyst with an alkylaluminum-based co-catalyst without injecting an internal donor, upon preparing a primary catalyst, and an external donor, upon polymerization. According to the present invention, the primary catalyst has superior reactivity with hydrogen, as chain transfer agent, allowing for preparation of low molecular weight amorphous polypropylene even under low hydrogen pressures and low-pressure driving conditions.