Ethylene-based polymers having a density from 0.94 to 0.96 g/cm.sup.3, a Mn from 5,000 to 14,000 g/mol, a ratio of Mw/Mn from 18 to 40, and at least one of a PENT value at 2.4 MPa of at least 11,500 hr and/or a W90 from 7.5 to 15 wt. % are disclosed. Additional ethylene polymers can have the same density, Mn, and Mw/Mn values, as well as a relaxation time from 0.5 to 3.5 sec, a CY-a parameter from 0.48 to 0.68, a HLMI from 5 to 11 g/10 min, a viscosity at HLMI from 3,000 to 7,500 Pa-sec, and a higher molecular weight component (HMW) and a lower molecular weight (LMW) component, in which a ratio of the number of SCBs at Mp of the HMW component to the number of SCBs at Mp of the LMW component is from 3.5 to 8.

The present disclosure relates to a method for preparing a polyolefin using a supported hybrid metallocene catalyst. According to the present disclosure, a polyolefin having a narrow molecular weight distribution can be prepared very effectively by introducing a cocatalyst in an optimum content in the presence of a supported hybrid metallocene catalyst containing two or more metallocene compounds having a specific chemical structure. The polyolefin prepared according to the present disclosure exhibits excellent uniformity in chlorine distribution in polyolefin during chlorination, thereby significantly improving elongation of the chlorinated polyolefin, compatibility with PVC and impact reinforcing performance. Thus, it exhibits excellent chemical resistance, weather resistance, flame retardancy, processability and impact strength reinforcing effect, and can be suitably applied as an impact reinforcing agent for PVC pipes and window profiles.

The present disclosure relates to a method for preparing a polyolefin using a supported hybrid metallocene catalyst. According to the present disclosure, a polyolefin having a narrow molecular weight distribution can be prepared very effectively by introducing a cocatalyst in an optimum content in the presence of a supported hybrid metallocene catalyst containing two or more metallocene compounds having a specific chemical structure. The polyolefin prepared according to the present disclosure exhibits excellent uniformity in chlorine distribution in polyolefin during chlorination, thereby significantly improving elongation of the chlorinated polyolefin, compatibility with PVC and impact reinforcing performance. Thus, it exhibits excellent chemical resistance, weather resistance, flame retardancy, processability and impact strength reinforcing effect, and can be suitably applied as an impact reinforcing agent for PVC pipes and window profiles.

A bimodal polymer composition comprising a lower molecular weight homopolymer and a higher molecular weight copolymer wherein the bimodal polymer composition has a density of from about 0.930 gram per cubic centimeter (g/cc) to about 0.970 g/cc, a ratio of high load melt index:melt index of from about 10 to about 150 and an Environmental Stress Crack Resistance (ESCR) of from about 25 hours to about 300 hours when measured in accordance with ASTM D1693 or ASTM D2561. A chromium-catalyzed polymer composition comprising (i) a lower molecular weight homopolymer and (ii) a higher molecular weight copolymer, wherein the bimodal polymer composition has an Environmental Stress Crack Resistance (ESCR) of from about 25 hours to about 300 hours when measured in accordance with ASTM D1693 or ASTM D2561.

A bimodal polymer composition comprising a lower molecular weight homopolymer and a higher molecular weight copolymer wherein the bimodal polymer composition has a density of from about 0.930 gram per cubic centimeter (g/cc) to about 0.970 g/cc, a ratio of high load melt index:melt index of from about 10 to about 150 and an Environmental Stress Crack Resistance (ESCR) of from about 25 hours to about 300 hours when measured in accordance with ASTM D1693 or ASTM D2561. A chromium-catalyzed polymer composition comprising (i) a lower molecular weight homopolymer and (ii) a higher molecular weight copolymer, wherein the bimodal polymer composition has an Environmental Stress Crack Resistance (ESCR) of from about 25 hours to about 300 hours when measured in accordance with ASTM D1693 or ASTM D2561.

The present invention relates to a process for producing a propylene polymer, such as a propylene homopolymer, a propylene-ethylene random copolymer or a heterophasic propylene copolymer using a specific class of metallocene complexes in combination with a cocatalyst system comprising a boron containing cocatalyst and an aluminoxane cocatalyst, preferably in a multistage polymerization process including a gas phase polymerization step.

The present invention relates to a process for producing a propylene polymer, such as a propylene homopolymer, a propylene-ethylene random copolymer or a heterophasic propylene copolymer using a specific class of metallocene complexes in combination with a cocatalyst system comprising a boron containing cocatalyst and an aluminoxane cocatalyst, preferably in a multistage polymerization process including a gas phase polymerization step.

The polyethylene according to the present invention has narrow particle size distribution, and can minimize a change in the crystal structure, and thus, it can be reacted with chlorine to prepare chlorinated polyethylene having excellent chlorination productivity and thermal stability.

The polyethylene according to the present invention has narrow particle size distribution, and can minimize a change in the crystal structure, and thus, it can be reacted with chlorine to prepare chlorinated polyethylene having excellent chlorination productivity and thermal stability.

The present invention relates to a process for the preparation of a procatalyst suitable for preparing a catalyst composition for olefin polymerization, said process comprising the steps of: Step A) providing or preparing a Grignard compound; Step B) contacting the Grignard compound with a silane compound to give a solid support; Step C) activating said solid support, comprising two sub steps: Step C1) contacting the solid support obtained in step B) with at least one first activating compound and a second activating compound; and Step C2) a second activation step by contacting the partly activated solid support obtained in step C1) with an activating electron donor; to obtain an activated solid support; Step D) reacting the activated solid support obtained in step C) with a halogen-containing Ti compound, optionally an activator and at least one internal electron donor in several sub steps to obtain said procatalyst. The invention moreover relates to a procatalyst, a catalytic system comprising said procatalyst and to a process to prepare polyolefins using said catalyst system and the polyolefins obtained therewith.