The invention provides a process for the preparation of a multimodal high density polyethylene (HDPE) having a melt flow rate (MFR.sub.2) of 0.1 to 4.0 g/10 min, said process comprising: (i) polymerising ethylene in a first polymerisation stage in the presence of a Ziegler-Natta catalyst to prepare a first ethylene homopolymer having a MFR.sub.2 from 10 to 500 g/10 min; (ii) polymerising ethylene in a second polymerisation stage in the presence of said catalyst and said first ethylene homopolymer to prepare an ethylene homopolymer mixture comprising said first ethylene homopolymer and a second ethylene homopolymer, said mixture having a MFR.sub.2 from 50 to 1000 g/10 min; and (iii) polymerising ethylene and at least one alpha-olefin comonomer in a third polymerisation stage in the presence of said catalyst and said ethylene homopolymer mixture to prepare said multimodal HDPE.

The invention provides a process for the preparation of a multimodal high density polyethylene (HDPE) having a melt flow rate (MFR.sub.2) of 0.1 to 4.0 g/10 min, said process comprising: (i) polymerising ethylene in a first polymerisation stage in the presence of a Ziegler-Natta catalyst to prepare a first ethylene homopolymer having a MFR.sub.2 from 10 to 500 g/10 min; (ii) polymerising ethylene in a second polymerisation stage in the presence of said catalyst and said first ethylene homopolymer to prepare an ethylene homopolymer mixture comprising said first ethylene homopolymer and a second ethylene homopolymer, said mixture having a MFR.sub.2 from 50 to 1000 g/10 min; and (iii) polymerising ethylene and at least one alpha-olefin comonomer in a third polymerisation stage in the presence of said catalyst and said ethylene homopolymer mixture to prepare said multimodal HDPE.

The present invention relates to a cable jacket composition comprising a multimodal olefin copolymer, said copolymer having density of 0.935-0.960 g/cm.sup.3 and MFR.sub.2 of 2.2-10.0 g/10 min and said composition having ESCR of at least 2000 hours and a cable shrinkage of 0.70% or lower. The invention further relates to the process for preparing said composition and its use as outer jacket layer for a cable, preferably a communication cable, most preferably a fiber optic cable.

The present invention relates to a cable jacket composition comprising a multimodal olefin copolymer, said copolymer having density of 0.935-0.960 g/cm.sup.3 and MFR.sub.2 of 2.2-10.0 g/10 min and said composition having ESCR of at least 2000 hours and a cable shrinkage of 0.70% or lower. The invention further relates to the process for preparing said composition and its use as outer jacket layer for a cable, preferably a communication cable, most preferably a fiber optic cable.

The present invention relates to a high-density ethylene-based polymer and a pipe using the same, the high-density ethylene-based polymer including: an ethylene homopolymer; or a copolymer of ethylene and at least one comonomer selected from the group consisting of an α-olefin, a cyclic olefin and linear, branched and cyclic dienes. The pipe using the high-density ethylene-based polymer of the present invention has more superior strain hardening than a conventional polyethylene resin pipe, and thus has excellent long-term pressure resistance characteristics and processability.

The present invention relates to a high-density ethylene-based polymer and a pipe using the same, the high-density ethylene-based polymer including: an ethylene homopolymer; or a copolymer of ethylene and at least one comonomer selected from the group consisting of an α-olefin, a cyclic olefin and linear, branched and cyclic dienes. The pipe using the high-density ethylene-based polymer of the present invention has more superior strain hardening than a conventional polyethylene resin pipe, and thus has excellent long-term pressure resistance characteristics and processability.

This disclosure relates to ethylene interpolymer compositions. Specifically, ethylene interpolymer products having: a Dilution Index (Y.sub.d) greater than 0; total catalytic metal 3.0 ppm; 0.03 terminal vinyl unsaturations per 100 carbon atoms, and; optionally a Dimensionless Modulus (X.sub.d) greater than 0. The disclosed ethylene interpolymer products have a melt index from about 0.3 to about 500 dg/minute, a density from about 0.869 to about 0.975 g/cm.sup.3, a polydispersity (M.sub.w/M.sub.n) from about 2 to about 25 and a CDBI.sub.50 from about 20% to about 97%. Further, the ethylene interpolymer products are a blend of at least two ethylene interpolymers; where one ethylene interpolymer is produced with a single-site catalyst formulation and at least one ethylene interpolymer is produced with a heterogeneous catalyst formulation.

This disclosure relates to ethylene interpolymer compositions. Specifically, ethylene interpolymer products having: a Dilution Index (Y.sub.d) greater than 0; total catalytic metal 3.0 ppm; 0.03 terminal vinyl unsaturations per 100 carbon atoms, and; optionally a Dimensionless Modulus (X.sub.d) greater than 0. The disclosed ethylene interpolymer products have a melt index from about 0.3 to about 500 dg/minute, a density from about 0.869 to about 0.975 g/cm.sup.3, a polydispersity (M.sub.w/M.sub.n) from about 2 to about 25 and a CDBI.sub.50 from about 20% to about 97%. Further, the ethylene interpolymer products are a blend of at least two ethylene interpolymers; where one ethylene interpolymer is produced with a single-site catalyst formulation and at least one ethylene interpolymer is produced with a heterogeneous catalyst formulation.

The present invention relates to a high-density ethylene-based polymer comprising: an ethylene homopolymer; or a copolymer of ethylene and at least one comonomer selected from the group consisting of -olefins, cyclic olefins and linear, branched and cyclic dienes. According to the present invention, the high-density ethylene-based polymer has a wide molecular weight distribution and excellent comonomer distribution characteristics, has excellent melt flowability due to a long chain branched structure, and has excellent mechanical characteristics since the comonomer distribution is concentrated in a high-molecular-weight body. The high-density ethylene polymer of the present invention has excellent molding processability during processing such as extrusion, compression, injection and rotational molding by having excellent mechanical characteristics and melt flowability.

The present invention relates to a high-density ethylene-based polymer comprising: an ethylene homopolymer; or a copolymer of ethylene and at least one comonomer selected from the group consisting of -olefins, cyclic olefins and linear, branched and cyclic dienes. According to the present invention, the high-density ethylene-based polymer has a wide molecular weight distribution and excellent comonomer distribution characteristics, has excellent melt flowability due to a long chain branched structure, and has excellent mechanical characteristics since the comonomer distribution is concentrated in a high-molecular-weight body. The high-density ethylene polymer of the present invention has excellent molding processability during processing such as extrusion, compression, injection and rotational molding by having excellent mechanical characteristics and melt flowability.