The polyethylene according to the present disclosure has a molecular structure having a narrow particle distribution and a low content of ultra-high molecular weight, so that a chlorinated polyethylene having excellent chlorination productivity and thermal stability may be prepared by reacting the polyethylene with chlorine. And, a PVC composition including the same with improved impact strength may also be prepared.

Disclosed herein are ethylene-based polymers generally characterized by a melt index of less than 1 g/10 min, a density from 0.93 to 0.965 g/cm.sup.3, a CY-a parameter at 190° C. of less than 0.2, an average number of short chain branches per 1000 total carbon atoms of the polymer in a molecular weight range of 400,000 to 600,000 g/mol that is greater than that in a molecular weight range of 40,000 to 60,000 g/mol, and an average number of long chain branches per 1000 total carbon atoms of the polymer in a molecular weight range of 400,000 to 600,000 g/mol that is greater than that in a molecular weight range of 4,000,000 to 6,000,000 g/mol. The ethylene polymers can be used to fabricate pipes, blown films, and blow molded products, and the ethylene polymers can be produced with a dual catalyst system containing a single atom bridged or two carbon atom bridged metallocene compound with two indenyl groups or an indenyl group and a cyclopentadienyl group, and a single atom bridged metallocene compound with a fluorenyl group and a cyclopentadienyl group with an alkenyl substituent.

Catalyst system, the catalyst system comprising (i) at least one metallocene complex of formula (I), (I) wherein Mt1 is Hf, X is a sigma-donor ligand, R.sup.1, R.sup.2, R.sup.3 are the same or different from each other and can be hydrogen or a saturated linear or branched C.sub.1-C.sub.10 alkyl, whereby the alkyl group can optionally contain up to 2 heteroatoms belonging to groups 14-16 of the periodic table, or R.sup.1 and R.sup.2 or R.sup.2 and R.sup.3 can form a ring having 4 to 6 C-atoms and 1 to 3 double bonds, R.sup.4 and R.sup.5 are the same or different from each other and can be saturated linear or branched C.sub.1-C.sub.10 alkyl, C.sub.5-C.sub.10 aryl, C.sub.6-C.sub.20 alkylaryl or C.sub.6-C.sub.20 arylalkyl groups, which can optionally contain up to 2 heteroatoms belonging to groups 14-16 of the periodic table, n can be 1 to 5, Ar is a C.sub.6-C.sub.20-aryl or -heteroarylgroup, which can be unsubstituted or substituted by 1 to 5 linear or branched C.sub.1-C.sub.10 alkyl group(s), and (ii) a boron containing cocatalyst.

##STR00001##

Disclosed herein are ethylene-based polymers generally characterized by a melt index of less than 1 g/10 min, a density from 0.93 to 0.965 g/cm.sup.3, a CY-a parameter at 190° C. of less than 0.2, an average number of short chain branches per 1000 total carbon atoms of the polymer in a molecular weight range of 400,000 to 600,000 g/mol that is greater than that in a molecular weight range of 40,000 to 60,000 g/mol, and an average number of long chain branches per 1000 total carbon atoms of the polymer in a molecular weight range of 400,000 to 600,000 g/mol that is greater than that in a molecular weight range of 4,000,000 to 6,000,000 g/mol. The ethylene polymers can be used to fabricate pipes, blown films, and blow molded products, and the ethylene polymers can be produced with a dual catalyst system containing a single atom bridged or two carbon atom bridged metallocene compound with two indenyl groups or an indenyl group and a cyclopentadienyl group, and a single atom bridged metallocene compound with a fluorenyl group and a cyclopentadienyl group with an alkenyl substituent.

Fibers can include a polypropylene composition, which can include a metallocene random copolymer of propylene and a comonomer that is an alpha-olefin different from propylene. The metallocene random copolymer can have a comonomer content of from 1.2 wt % to 1.8 wt %, a molecular weight distribution of at least 1.0 and of at most 4.0 obtained without thermal or chemical degradation, and a melting temperature T.sub.melt of at most 140 C. A nonwoven can include the fibers, and a laminate can include the nonwoven. The fibers can be produced by polymerizing the propylene and comonomer in presence of a metallocene-based polymerization catalyst to obtain the metallocene random copolymer. The polypropylene composition can be melt-extruded to obtain a molten polypropylene stream, which can be extruded from capillaries of a spinneret to obtain filaments. A diameter of the filaments can be rapidly reduced to obtain a final diameter.

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 conent 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.

Disclosed herein are ethylene-based polymers generally characterized by a melt index of less than 1 g/10 min, a density from 0.93 to 0.965 g/cm.sup.3, a CY-a parameter at 190 C. of less than 0.2, an average number of short chain branches per 1000 total carbon atoms of the polymer in a molecular weight range of 400,000 to 600,000 g/mol that is greater than that in a molecular weight range of 40,000 to 60,000 g/mol, and an average number of long chain branches per 1000 total carbon atoms of the polymer in a molecular weight range of 400,000 to 600,000 g/mol that is greater than that in a molecular weight range of 4,000,000 to 6,000,000 g/mol. The ethylene polymers can be used to fabricate pipes, blown films, and blow molded products, and the ethylene polymers can be produced with a dual catalyst system containing a single atom bridged or two carbon atom bridged metallocene compound with two indenyl groups or an indenyl group and a cyclopentadienyl group, and a single atom bridged metallocene compound with a fluorenyl group and a cyclopentadienyl group with an alkenyl substituent.

Fibers can include a polypropylene composition, which can include a metallocene random copolymer of propylene and a comonomer that is an alpha-olefin different from propylene. The metallocene random copolymer can have a comonomer content of from 1.2 wt % to 1.8 wt %, a molecular weight distribution of at least 1.0 and of at most 4.0 obtained without thermal or chemical degradation, and a melting temperature T.sub.melt of at most 140 C. A nonwoven can include the fibers, and a laminate can include the nonwoven. The fibers can be produced by polymerizing the propylene and comonomer in presence of a metallocene-based polymerization catalyst to obtain the metallocene random copolymer. The polypropylene composition can be melt-extruded to obtain a molten polypropylene stream, which can be extruded from capillaries of a spinneret to obtain filaments. A diameter of the filaments can be rapidly reduced to obtain a final diameter.

The present invention relates to a transition metal compound for an olefin polymerization catalyst, represented by chemical formula 1. The description of chemical formula 1 is as described in the specification.

An object of the invention is to provide a solid polyaluminoxane composition suitably used as a cocatalyst and a catalyst carrier in combination with an olefin oligomerization or polymerization catalyst, without the use of solid inorganic carriers such as silica. The solid polyaluminoxane composition of the invention includes a polyalkylaluminoxane and a trialkylaluminum, and has a solubility in n-hexane at 25 C. of less than 0.50 mol % as measured by a specific method (i), a solubility in toluene at 25 C. of less than 1.0 mol % as measured by a specific method (ii), and a 13 mol % or more molar fraction of alkyl groups derived from the trialkylaluminum moieties relative to the total number of moles of alkyl groups derived from the polyalkylaluminoxane moieties and the alkyl groups derived from the trialkylaluminum moieties as measured with respect to tetrahydrofuran-d.sub.8 soluble components by a specific method (iii).