Prepolymerization method of α-olefin

1. A method of prepolymerizing an α-olefin comprising:

contacting an α-olefin with a catalyst system, wherein the catalyst system comprises:

a magnesium supported solid complex titanium catalyst; and

an organometallic compound of metal of Group I or II of the Periodic Table,

wherein an inert solvent is used as a reaction medium, and wherein the inert solvent comprises mineral oil, and wherein the inert solvent has a molecular weight of 300 g/mole or more, and wherein the viscosity of the inert solvent is about 50 to about 100 centistokes at 40° C.

2. The method of claim 1 , wherein said organometallic compound is trialkylalunuinium.

3. The method of claim 1 , wherein the ratio of said solid complex titanium catalyst (a) to the inert solvent is 5 to 500 millimoles of titanium atoms per one liter of the inert solvent, and the ratio of organometals in the organometallic compound (b) component to the catalyst (a) is 0.1 to 100 moles per one mole of titanium atoms in the catalyst (a).

4. The method of claim 1 , wherein the magnesium supported solid complex titanium catalyst comprises a Zieglar-Natta catalyst.

5. The method of claim 1 , wherein the magnesium supported solid complex titanium catalyst is prepared by a method comprising:

preparing a solution containing magnesium by dissolving a magnesium compound and a Group IIIA compound of the Periodic Table in a solvent mixture of cyclic ether, one or more of alcohol, a phosphorus compound and organosilane;

precipitating solid particles by reacting the solution containing magnesium with a transition metal compound, a silicone compound, or a tin compound;

reacting said precipitated solid particles with a titanium compound and an electron donor; and

washing the reaction product with hydrocarbon solvents to obtain solid catalyst particles.

6. The method of claim 1 , wherein the catalyst system comprises particles with a diameter of 100 μm or more.