Abstract: The present invention is a solid catalyst component for polymerization of olefins prepared by contacting a magnesium compound, a tetravalent halogen-containing titanium compound, a diester of an aromatic dicarboxylic acid, an aromatic hydrocarbon and an organic aluminum compound containing a hydroxyl group represented by the following general formula (R1CO2)mAl(OH)3-m or aluminum hydroxide. The catalyst for polymerization of olefins comprising said solid catalyst component, an organic aluminum compound represented by the general formula R2pAlQ3-p and an organic silicon compound represented by the general formula R3qSi(OR4)4-q can retard the rate of forming a polymer having a low molecular weight or a low stereoregular polymer which is soluble in a polymerization solvent in slurry polymerization and can obtain a high stereoregular polymer in a high yield, and also can obtain a copolymer having an excellent property in a high yield in the copolymerization of olefins.

Abstract: The objective of the present invention is to provide a solid catalyst component and a catalyst for polymerization of olefins, which shows a high activity, can lower the rate of forming a polymer having a low molecular weight or a low stereoregular polymer which is soluble in a polymerization solvent and can obtain a high stereoregular polymer in a high yield. The present invention is a solid catalyst component(A) for polymerization of olefins prepared by contacting (a) dialkoxymagnesium, (b) a titanium compound, (c) a diester of an aromatic dicarboxylic acid, (d) an aromatic hydrocarbon and (e) an organic silicon compound containing a hydroxyl group, and a catalyst for polymerization of olefins prepared from the solid catalyst component (A) , an organic aluminum compound (B) represented by the general formula R2pAlQ3-p and an organic silicon compound (C) represented by the general formula R3qSi(OR4)4-q.

Abstract: A propylene homopolymer having a high stereo-regularity and an excellent processability during sheet or film formation, characterized in that it exhibits a melt flow rate (MFR) of from 0.1 to 20 g/10 min., a xylene-soluble component content of not more than 6% by weight and an isoblock content [IB] of at least 3 mol % as determined by the following equation (1) from Pmmmr, Pmmrr and Pmrrm, which are absorption intensities attributed to isoblock chain in xylene-insoluble component by .sup.13 C-NMR spectrum:[IB]=[Pmmmr]+[Pmmrr]+[Pmrrm] (1)wherein [Pmmmr], [Pmmrr] and [Pmrrm] are the relative intensity ratio (mol %) of Pmmmr, Pmmrr and Pmrrm, respectively, which are absorption intensities attributed to isoblock chain.

Abstract: A solid catalyst component (A1) for polymerization of olefins prepared by contact with a solid component (d) obtained by allowing (1) a solid component (a) obtained by allowing (i) a dialkoxymagnesium or diaryloxymagnesium, (ii) a titanium compound and (iii) a diester of aromatic dicarboxylic acid to come in contact with one another and (2) a solid component (b) obtained by allowing (i) a dialkoxymagnesium or diaryloxymagnesium, (ii) a titanium compound, (iii) a diester of aromatic dicarboxylic acid and (iv) a polysiloxane to come in contact with one another, to come in contact with each other, or a solid catalyst component (A2) for polymerization of olefins prepared by allowing said solid component (a) and (3) a solid component (d) obtained by allowing (i) a dialkoxymagnesium or diaryloxymagnesium, (ii) a titanium compound, (iii) a diester of aromatic dicarboxylic acid, (iv) a polysiloxane and (v) an aluminum compound to come in contact with one another, to come in contact with each other.

Abstract: The present invention provides a solid catalyst component (A) obtained by allowing a dialkoxymagnesium or diaryloxymagnesium, a titanium compound, a diester of phthalic acid and a cyclic or chain polysiloxane to come in contact with one another.Further, the present invention provides a catalyst for polymerization of olefins prepared from the foregoing solid catalyst component (A), an organic aluminum compound and an organic silicon compound.

Abstract: A solid catalyst component for polymerizing olefins, which can provide a streoregular polymer having a low density of 0.900 to 0.906 g/ml at a high yield and a low RDS and which can prepare the polymer containing less fine powders. The solid catalyst component is prepared using substances (a) to (d) and optionally substance (e):(a) a dialkoxymagnesium represented by Mg(OR.sup.1).sub.2, wherein R represents a straight chain or branched chain alkyl group or an aryl group;(b) an aluminium compound represented by Al(OR.sup.2).sub.n X.sup.1.sub.3-n, wherein R.sup.2 represents a straight chain or branched chain alkyl group; X.sup.1 represents a halogen atom, and n is 0 or an integer of 1 to 3;(c) titanium tetrachloride;(d) a diester of dicarboxylic acid; and(e) a dimethyl polysiloxane.