A high density, high polydispersity polyethylene having improved properties, and a process of producing same.

A high density, high polydispersity polyethylene having improved properties, and a process of producing same.

Disclosed are metallocene compounds, catalyst compositions comprising at least one metallocene compound, processes for polymerizing olefins, methods for making catalyst compositions, olefin polymers and articles made from olefin polymers. In an aspect, a metallocene compound and catalyst composition are disclosed in which the metallocene contains at least one indenyl ligand, the indenyl ligand containing at least one halogenated substituent, such as a fluorinated substituent. These metallocene compounds and catalyst compositions can produce polyethylene having unexpectedly low levels of short chain branching.

Disclosed are metallocene compounds, catalyst compositions comprising at least one metallocene compound, processes for polymerizing olefins, methods for making catalyst compositions, olefin polymers and articles made from olefin polymers. In an aspect, a metallocene compound and catalyst composition are disclosed in which the metallocene contains at least one indenyl ligand, the indenyl ligand containing at least one halogenated substituent, such as a fluorinated substituent. These metallocene compounds and catalyst compositions can produce polyethylene having unexpectedly low levels of short chain branching.

The invention relates to a process for the preparation of a multimodal copolymer of ethylene and a comonomer which is 1-hexene and/or 1-butene in a series of polymerization reactors comprising at least a first polymerization reactor and a second polymerization reactor, the process comprising: a) feeding ethylene, hydrogen and catalyst components (1) and a first diluent (29) to the first polymerization reactor (A) to prepare a first suspension (3) of solid particles of a first ethylene polymer in a first suspension medium, wherein the first diluent (29) comprises branched heptane and is essentially free of the comonomer; b) feeding the first suspension (3) to a flash drum (E) for vaporizing a part of the first suspension medium to obtain a hydrogen-depleted suspension (4), c) feeding the hydrogen-depleted suspension (4), ethylene and comonomer (9) and a second diluent (24 & 34) to the second polymerization reactor (H) to prepare a second suspension (11) of solid particles of a second ethylene polymer in a second suspension medium, wherein the second diluent (24 & 34) comprises branched heptane and the comonomer dissolved in the second diluent, d) processing the second suspension (11) to obtain a dry effluent (15) of the solid particles of the second ethylene polymer and a liquid stream (23) comprising branched heptane, the comonomer, and low molecular weight hydrocarbon reaction products, e) feeding at least part (25) of the liquid stream (23) to an evaporation system (Q) for separating non-volatile, low-molecular-weight hydrocarbon reaction products and subsequently to a distillation column (R) for separating the comonomer from branched heptane to obtain 1) a branched heptane liquid stream (29) essentially free of the comonomer, 2) a vapor distillate (31) comprising the comonomer and branched heptane and 3) a liquid distillate (30) comprising branched heptane and the comonomer, f) feeding the liquid distillate stream (30) to the second polymerization reactor (B) to form at least part of the second diluent (34) and g) feeding the branched heptane liquid stream (29) to the first polymerization reactor as the first diluent.

Ethylene-based polymers are characterized by a melt index less than 1 g/10 min, a density from 0.94 to 0.965 g/cm.sup.3, a Mw from 100,000 to 250,000 g/mol, a relaxation time from 0.5 to 3 sec, and an average number of long chain branches (LCBs) per 1,000,000 total carbon atoms in a molecular weight range of 300,000 to 900,000 g/mol that is greater than that in a molecular weight range of 1,000,000 to 2,000,000 g/mol, or an average number of LCBs per 1,000,000 total carbon atoms in a molecular weight range of 1,000,000 to 2,000,000 g/mol of less than or equal to about 5 and a maximum ratio of η.sub.E/3η at an extensional rate of 0.1 sec.sup.−1 from 1.2 to 10. These polymers have substantially no long chain branching in the high molecular weight fraction of the polymer, but instead have significant long chain branching in a lower molecular weight fraction, such that polymer melt strength and parison stability are maintained for the fabrication of blow molded products and other articles of manufacture. These ethylene polymers can be produced using a dual catalyst system containing a single or two atom bridged metallocene compound with two indenyl groups, and a single atom bridged metallocene compound with a fluorenyl group and a cyclopentadienyl group.

Ethylene-based polymers are characterized by a melt index less than 1 g/10 min, a density from 0.94 to 0.965 g/cm.sup.3, a Mw from 100,000 to 250,000 g/mol, a relaxation time from 0.5 to 3 sec, and an average number of long chain branches (LCBs) per 1,000,000 total carbon atoms in a molecular weight range of 300,000 to 900,000 g/mol that is greater than that in a molecular weight range of 1,000,000 to 2,000,000 g/mol, or an average number of LCBs per 1,000,000 total carbon atoms in a molecular weight range of 1,000,000 to 2,000,000 g/mol of less than or equal to about 5 and a maximum ratio of η.sub.E/3η at an extensional rate of 0.1 sec.sup.−1 from 1.2 to 10. These polymers have substantially no long chain branching in the high molecular weight fraction of the polymer, but instead have significant long chain branching in a lower molecular weight fraction, such that polymer melt strength and parison stability are maintained for the fabrication of blow molded products and other articles of manufacture. These ethylene polymers can be produced using a dual catalyst system containing a single or two atom bridged metallocene compound with two indenyl groups, and a single atom bridged metallocene compound with a fluorenyl group and a cyclopentadienyl group.

A bimodal ethylene-co-1-hexene copolymer composition consisting of a higher molecular weight component and a lower molecular weight component and, when in melted form at 190 degrees Celsius, is characterized by a melt property performance defined by a combination of melt index (5 kg), melt strength, and, optionally, shear thinning properties, and, when in solid form, is characterized by a slow crack growth property performance defined by a combination of strain hardening modulus and accelerated full-notch creep test performance. A pipe consisting of the bimodal ethylene-co-1-hexene copolymer composition. A method of synthesizing the bimodal ethylene-co-1-hexene copolymer composition. A method of making the pipe. A manufactured article, which is not a pipe, comprising the bimodal ethylene-co-1-hexene copolymer composition.

A bimodal ethylene-co-1-hexene copolymer composition consisting of a higher molecular weight component and a lower molecular weight component and, when in melted form at 190 degrees Celsius, is characterized by a melt property performance defined by a combination of melt index (5 kg), melt strength, and, optionally, shear thinning properties, and, when in solid form, is characterized by a slow crack growth property performance defined by a combination of strain hardening modulus and accelerated full-notch creep test performance. A pipe consisting of the bimodal ethylene-co-1-hexene copolymer composition. A method of synthesizing the bimodal ethylene-co-1-hexene copolymer composition. A method of making the pipe. A manufactured article, which is not a pipe, comprising the bimodal ethylene-co-1-hexene copolymer composition.

The present invention is directed to a polyolefin composition comprising a blend of a heterophasic polypropylene composition and 5.0 to 30.0 wt % of an ethylene homo- or copolymer, the ethylene homo- or copolymer having a density of at least 941 kg/m.sup.3 and a melt flow rate MFR.sub.21 of 1 to 10 g/10 min. The heterophasic polypropylene composition comprises a propylene homopolymer or a propylene ethylene random copolymer and an elastomeric ethylene propylene rubber, and is characterized by 75.0 to 95.0 wt % of a crystalline fraction having an ethylene content of up to 4.0 wt % and an MFR.sub.2 of 0.1 to 100 g/10 min, and 5.0 to 25.0 wt % of a soluble fraction having an ethylene content of 10.0 to 70.0 wt % and an intrinsic viscosity of 1.0 to 4.0 dl/kg, wherein the crystalline fraction and the soluble fraction are determined in 1,2,4-trichlorobenzene at 40° C.