The present disclosure relates to a Ziegler-Natta catalyst system with self-extinguishing properties suitable for olefin polymerization. The catalyst system of the present disclosure comprises a pro-catalyst, a co-catalyst, and an external donor having a mixture of a selectivity control agent and an activity control agent. The catalyst system of the present disclosure is adapted to prevent the temperature of the polymerization reaction to go beyond the softening temperature of the polymer, thereby exhibiting the self-extinguishing properties.

A polyethylene composition for producing blow-molded hollow articles, having the following features: 1) density from 0.940 to 0.955 g/cm.sup.3, determined according to ISO 1183 at 23° C.; 2) ratio MIF/MIP from 12 to 40; 3) Mz from 500,000 to 3,500,000 g/mol; 4) η.sub.0.02 from 80,000 to 300,000 Pa.Math.s; 5) HMWcopo index from 1 to 15; and 6) Mz/Mw*LCBI lower than 6.4.

A polyethylene composition for producing blow-molded hollow articles, having the following features: 1) density from 0.940 to 0.955 g/cm.sup.3, determined according to ISO 1183 at 23° C.; 2) ratio MIF/MIP from 12 to 40; 3) Mz from 500,000 to 3,500,000 g/mol; 4) η.sub.0.02 from 80,000 to 300,000 Pa.Math.s; 5) HMWcopo index from 1 to 15; and 6) Mz/Mw*LCBI lower than 6.4.

The present invention relates to Ziegler-Natta catalyst components for olefin polymerization employing specific carbonate compounds as an element of solid catalyst composition in conjunction with at least one or more internal donor compounds, for producing polyolefins, particularly polypropylene and ethylene-propylene block co-polymer, which exhibits substantially high rubber content with higher stereo-regularity and hydrogen response.

The present invention relates to Ziegler-Natta catalyst components for olefin polymerization employing specific carbonate compounds as an element of solid catalyst composition in conjunction with at least one or more internal donor compounds, for producing polyolefins, particularly polypropylene and ethylene-propylene block co-polymer, which exhibits substantially high rubber content with higher stereo-regularity and hydrogen response.

An object of the present invention is to provide a film for a capacitor such that the film excels in high-temperature dielectric breakdown voltage (high-temperature BDV) and has blocking resistance, and bleeding-out of, for instance, a nucleating agent is suppressed even after long-term storage. The present invention pertains to a multilayer polypropylene film for a capacitor, the film including a base layer composed of a propylene polymer composition containing a propylene homopolymer (X) and 0.0001 to 0.05 mass % of a polymer-based α-crystal nucleating agent (C), and a front layer or a back layer composed of a propylene-based polymer (Y) on at least one surface of the base layer, wherein the base layer and the front layer or back layer are stretched.

An object of the present invention is to provide a film for a capacitor such that the film excels in high-temperature dielectric breakdown voltage (high-temperature BDV) and has blocking resistance, and bleeding-out of, for instance, a nucleating agent is suppressed even after long-term storage. The present invention pertains to a multilayer polypropylene film for a capacitor, the film including a base layer composed of a propylene polymer composition containing a propylene homopolymer (X) and 0.0001 to 0.05 mass % of a polymer-based α-crystal nucleating agent (C), and a front layer or a back layer composed of a propylene-based polymer (Y) on at least one surface of the base layer, wherein the base layer and the front layer or back layer are stretched.

Disclosed herein is a method for producing a solid catalyst component for olefin polymerization that is capable of reducing the amount of fine powder contained in the solid catalyst component for olefin polymerization. The method includes the step of reacting a magnesium compound and a titanium halide compound with each other so that a maximum heat release rate per mole of the magnesium compound is 18 W or less. Also disclosed herein is a method for producing a solid catalyst component for olefin polymerization that is capable of preventing a reduction in polymerization activity caused by application of heat to the solid catalyst component for olefin polymerization. The method includes the step of reacting a magnesium compound and a titanium halide compound with each other so that a total heat release value per mole of the titanium compound is 6 kJ to 90 kJ.

Disclosed herein is a method for producing a solid catalyst component for olefin polymerization that is capable of reducing the amount of fine powder contained in the solid catalyst component for olefin polymerization. The method includes the step of reacting a magnesium compound and a titanium halide compound with each other so that a maximum heat release rate per mole of the magnesium compound is 18 W or less. Also disclosed herein is a method for producing a solid catalyst component for olefin polymerization that is capable of preventing a reduction in polymerization activity caused by application of heat to the solid catalyst component for olefin polymerization. The method includes the step of reacting a magnesium compound and a titanium halide compound with each other so that a total heat release value per mole of the titanium compound is 6 kJ to 90 kJ.

Processes for forming a polypropylene composition are provided herein comprising the steps of making a first propylene-based copolymer having a molecular weight distribution between 3 to 8.5, and making a second propylene-based polymer in the presence of the first propylene-based polymer to produce the polypropylene composition having a high molecular weight tail in the amount of between 1.0 wt. % and 10.0 wt. %. The polypropylene compositions produced have a broad molecular weight distribution and high molecular weight tail to provide improved stiffness while retaining toughness.