Provided is a solid catalyst component for olefin polymerization comprising an electron-donating compound other than a phthalate, the solid catalyst component being equal in the olefin-polymerizing activity and in the primary physical properties of the resulting polymer such as stereoregularity and molecular weight distribution to those with use of a phthalate as an electron-donating compound. A solid catalyst component for olefin polymerization comprises a magnesium atom, a titanium atom, a halogen atom, an ester compound (A) represented by a general formula (1) and a diester compound (B) represented by a general formula (2), wherein

a ratio represented by the following expression:

(content (mass %) of ester compound (A)/content (mass %) of diester compound (B))

is 0.05 to 50.

Provided is a novel olefin polymer which is excellent in lightness and moldability, has high rigidity and yields molded products excellent in flexural elasticity. The olefin polymer includes a propylene initial polymerization product formed in the presence of an olefin polymerization catalyst which is a contact reaction product of an olefin polymerization solid catalyst component containing a titanium atom, a magnesium atom, a halogen atom and an internal electron donating compound, at least one organoaluminum compound selected from the compounds of the general formula (I), and a first external electron donating compound; and a polypropylene part formed of a propylene polymerization product formed in the presence of the olefin polymerization catalyst and a second external electron donating compound higher in adsorption to the surface of the olefin polymerization solid catalyst component than the first external electron donating compound.

Provided is a novel olefin polymer which is excellent in lightness and moldability, has high rigidity and yields molded products excellent in flexural elasticity. The olefin polymer includes a propylene initial polymerization product formed in the presence of an olefin polymerization catalyst which is a contact reaction product of an olefin polymerization solid catalyst component containing a titanium atom, a magnesium atom, a halogen atom and an internal electron donating compound, at least one organoaluminum compound selected from the compounds of the general formula (I), and a first external electron donating compound; and a polypropylene part formed of a propylene polymerization product formed in the presence of the olefin polymerization catalyst and a second external electron donating compound higher in adsorption to the surface of the olefin polymerization solid catalyst component than the first external electron donating compound.

A colloidal suspension includes an organic phase and a complex of Formula I as precursor for Ziegler-Natta catalyst synthesis:

XTiCl.sub.p(OR.sup.1).sub.4p.Math.YMg(OR.sup.2).sub.q(OR.sup.3).sub.t(I).

In Formula I, a molar ratio of X to Y (X/Y) is from 0.2 to 5.0, p is 0 or 1, 0<q<2, 0<t<2, the sum of q and t is 2, R.sup.1, R.sup.2, and R.sup.3 are each independently a linear or branched alkyl, a linear or branched heteroalkyl, a cycloalkyl, a substituted cycloalkyl, a substituted heterocycloalkyl, a substituted aryl, or a (heteroaryl)alkyl; and R.sup.2 is not the same as R.sup.3.

A colloidal suspension includes an organic phase and a complex of Formula I as precursor for Ziegler-Natta catalyst synthesis:

XTiCl.sub.p(OR.sup.1).sub.4p.Math.YMg(OR.sup.2).sub.q(OR.sup.3).sub.t(I).

In Formula I, a molar ratio of X to Y (X/Y) is from 0.2 to 5.0, p is 0 or 1, 0<q<2, 0<t<2, the sum of q and t is 2, R.sup.1, R.sup.2, and R.sup.3 are each independently a linear or branched alkyl, a linear or branched heteroalkyl, a cycloalkyl, a substituted cycloalkyl, a substituted heterocycloalkyl, a substituted aryl, or a (heteroaryl)alkyl; and R.sup.2 is not the same as R.sup.3.

A colloidal suspension includes an organic phase and a complex of Formula I as precursor for Ziegler-Natta catalyst synthesis:

XTiCl.sub.p(OR.sup.1).sub.4-p.YMg(OR.sup.2).sub.q(OR.sup.3).sub.t (I).

In Formula I, a molar ratio of X to Y (X/Y) is from 0.2 to 5.0, p is 0 or 1, 0<q<2, 0<t<2, the sum of q and t is 2, R.sup.1, R.sup.2, and R.sup.3 are each independently a linear or branched alkyl, a linear or branched heteroalkyl, a cycloalkyl, a substituted cycloalkyl, a substituted heterocycloalkyl, a substituted aryl, or a (heteroaryl)alkyl; and R.sup.2 is not the same as R.sup.3.

A colloidal suspension includes an organic phase and a complex of Formula I as precursor for Ziegler-Natta catalyst synthesis:

XTiCl.sub.p(OR.sup.1).sub.4-p.YMg(OR.sup.2).sub.q(OR.sup.3).sub.t (I).

In Formula I, a molar ratio of X to Y (X/Y) is from 0.2 to 5.0, p is 0 or 1, 0<q<2, 0<t<2, the sum of q and t is 2, R.sup.1, R.sup.2, and R.sup.3 are each independently a linear or branched alkyl, a linear or branched heteroalkyl, a cycloalkyl, a substituted cycloalkyl, a substituted heterocycloalkyl, a substituted aryl, or a (heteroaryl)alkyl; and R.sup.2 is not the same as R.sup.3.

A catalyst component for olefin polymerization includes magnesium, titanium, a halogen, an internal electron donor compound, and a precipitation aid. The precipitation aid includes a precipitation aid represented by general formula (I). The precipitation aid represented by general formula (I) includes isomers represented by general formula (I-a) and/or (I-b).

##STR00001##

A catalyst component for olefin polymerization includes magnesium, titanium, a halogen, an internal electron donor compound, and a precipitation aid. The precipitation aid includes a precipitation aid represented by general formula (I). The precipitation aid represented by general formula (I) includes isomers represented by general formula (I-a) and/or (I-b).

##STR00001##

The present invention relates to a method of producing a magnesium compound represented by the following formula: Mg(OR.sup.1).sub.2-n(Modifier).sub.n wherein R.sup.1 is C.sub.mH.sub.2m+1, where in m is an integer from 2 to 10, and n is 0-2 wherein the method comprises the steps a) providing a mixture comprising magnesium, an initiator and a first alcohol wherein the molar ratio of initiator to magnesium is from 0.0001 to 1; and b) adding a modifier to the mixture obtained in step a) wherein the modifier is selected from the group consisting of alkoxy alcohol, carboxylic acid ester, aliphatic hydrocarbon, aromatic hydrocarbon, ketone, a second alcohol or a mixture thereof, wherein the second alcohol is different from the first alcohol, respective magnesium compound and the use thereof.