Abstract: It is an object of the present invention to provide a modified propylene resin containing very small amounts of low-crystalline and low-molecular-weight components. The present invention relates to a modified propylene resin characterized by satisfying the following requirements (1) to (4). (1) The melting point (Tm) measured with a differential scanning calorimeter (DSC) is 140° C. or higher. (2) The amount of grafts of ethylenic unsaturated bond-containing monomer after hot xylene washing is 0.1 to 5 percent by weight. (3) The amount of components soluble in o-dichlorobenzene at 70° C. is 1.5 percent by weight or less. (4) The intrinsic viscosity [?] is 0.1 to 4 dl/g.

Abstract: It is an object of the present invention to provide a modified propylene resin containing very small amounts of low-crystalline and low-molecular-weight components. The present invention relates to a modified propylene resin characterized by satisfying the following requirements (1) to (4). (1) The melting point (Tm) measured with a differential scanning calorimeter (DSC) is 140° C. or higher. (2) The amount of grafts of ethylenic unsaturated bond-containing monomer after hot xylene washing is 0.1 to 5 percent by weight. (3) The amount of components soluble in o-dichlorobenzene at 70° C. is 1.5 percent by weight or less. (4) The intrinsic viscosity [?] is 0.1 to 4 dl/g.

Abstract: A method for producing a polyolefin is disclosed which comprises polymerizing an .alpha.-olefin in the presence of a catalyst composition comprising (A) a solid catalyst component prepared by contacting (a) a solid component comprising a magnesium alkoxide and/or a magnesium salt of a fatty acid supported on an inorganic oxide composed of at least one member selected from the group consisting of oxides of elements belonging to Groups II, III and IV of the periodic table and/or a composite inorganic oxide containing at least one member selected from the group consisting of oxides of elements belonging to Groups II, III and IV of the periodic table, the inorganic oxide or composite inorganic oxide having a surface hydroxide concentration of 3 .mu.mol/m.sup.2 or less, (b) an electron donating compound and (c) a titanium halide, (B) an organic metal compound, and (C) an electron donating compound.

Abstract: A method of producing a polyolefin. An olefin is polymerized in the presence of a catalyst containing (A) a catalyst component containing magnesium, titanium, halogen and an electron donor, (B) an organoaluminum compound and (C) an external electron donor which is an ether compound (C.sup.1) of the formula [1a]: ##STR1## or formula [1b]: ##STR2## wherein R.sup.1, R.sup.2, R.sup.4 and R.sup.7 are saturated or unsaturated aliphatic hydrocarbyl group having 1 to 7 carbon atoms; R.sup.3 and R.sup.6 are a hydrogen atom or a saturated or unsaturated aliphatic hydrocarbyl group having 1 to 7 carbons and R.sup.5 is a divalent aliphatic hydrocarbyl group having 1 to 7 carbon atoms. The catalyst used in the polymerization may also contain a carboxylate, organosilicon compound and/or an azo compound.