Bimodal high-density polyethylene polymer compositions with increased high melt strength and good processability. The compositions comprise a base resin having a density of about 945 kg/m.sup.3 to about 955 kg/m.sup.3, and an ethylene polymer (A) having a density of at least about 968 kg/m.sup.3, in an amount ranging from 45% to 55% by weight and an ethylene polymer (B) having a density lower than the density of polymer (A). The composition has a complex viscosity at a shear rate of 0.01 rad/s ranging from about 200 to 450 kPa.Math.s and a complex viscosity at a shear rate of 100 rad/s ranging from about 1900 to 2500 Pa.Math.s. Articles made from these compositions, such as pipes and fittings achieve long-term oxidative resistance and have a low wall thickness variability while maintaining high production output.

The present disclosure relates to compositions including copolymers, and methods for making compositions. In an embodiment, a composition includes the product of a copolymer comprising at least 50 mol % propylene and at least 1 wt % of at least one of ethylene or a C.sub.4 to C.sub.10 α-olefin, based on the total weight of the copolymer; and an organic peroxide. The copolymer has Mw.sub.MALLS/Mn.sub.MALLS of from 1 to 5. In an embodiment, a process to form a composition includes introducing a copolymer with an organic peroxide, the copolymer comprising at least 50 mol % propylene and at least 1 wt % of at least one of ethylene or a C.sub.4 to C.sub.10 α-olefin, based on the total weight of the copolymer; and obtaining a composition comprising a product of the copolymer and the organic peroxide. The copolymer has Mw.sub.MALLS/Mn.sub.MALLS of from 1 to 5.

A method for making a polymer composition comprises the steps of providing a heterophasic thermoplastic polymer composition, providing a compatibilizing agent, providing a peroxide compound, and mixing and melting the heterophasic thermoplastic polymer composition, compatibilizing agent, and peroxide compound. The compatibilizing agent comprises an ester compound formally derived from a polyol comprising three or more hydroxy groups and an aliphatic carboxylic acid comprising one or more carbon-carbon double bonds. A modified polymer composition comprises a heterophasic thermoplastic polymer composition and a compatibilizing agent. The modified polymer composition has an ethylene discontinuous phase present in the form of discrete particles in a propylene continuous phase. The discrete particles of the ethylene discontinuous phase are present in the modified polymer composition in a concentration of 2.1 or more particles per cubic micron.

The present disclosure provides a foamable composition containing (A) a high density polyethylene (HDPE); (B) a low density polyethylene (LDPE); (C) a peroxide-modified HDPE; and (D) a nucleator. The present disclosure also provides a process for making a foam composition. Additionally, the present disclosure provides a foam formed from a foamable composition, and a cable with an insulation layer containing the foam.

The present disclosure provides a foamable composition containing (A) a high density polyethylene (HDPE); (B) a low density polyethylene (LDPE); (C) a peroxide-modified HDPE; and (D) a nucleator. The present disclosure also provides a process for making a foam composition. Additionally, the present disclosure provides a foam formed from a foamable composition, and a cable with an insulation layer containing the foam.

A composition comprising a low density polyethylene (LDPE) and a peroxide-treated metallocene-catalyzed linear low density polyethylene (pmLLDPE), wherein the composition when extruded as a molten resin displays a neck-in value that is (i) decreased when compared to the neck-in value observed when using the LDPE alone, (ii) about equal to the neck-in value observed when using the LDPE alone, or (iii) increased by <10% of the neck-in value observed when using the LDPE alone. The composition when extruded as a molten resin displays a neck-in value that is decreased by ≥5% when compared with a neck-in value of an otherwise similar composition comprising the LDPE and a metallocene-catalyzed linear low density polyethylene (mLLDPE) that has not been peroxide-treated. The composition comprises 1-80 wt. % pmLLDPE. The pmLLDPE has a melt index of ≤0.9 g/10 min, when tested in accordance with ASTM D1238 under a force of 2.16 kg.

A composition comprising a low density polyethylene (LDPE) and a peroxide-treated metallocene-catalyzed linear low density polyethylene (pmLLDPE), wherein the composition when extruded as a molten resin displays a neck-in value that is (i) decreased when compared to the neck-in value observed when using the LDPE alone, (ii) about equal to the neck-in value observed when using the LDPE alone, or (iii) increased by <10% of the neck-in value observed when using the LDPE alone. The composition when extruded as a molten resin displays a neck-in value that is decreased by ≥5% when compared with a neck-in value of an otherwise similar composition comprising the LDPE and a metallocene-catalyzed linear low density polyethylene (mLLDPE) that has not been peroxide-treated. The composition comprises 1-80 wt. % pmLLDPE. The pmLLDPE has a melt index of ≤0.9 g/10 min, when tested in accordance with ASTM D1238 under a force of 2.16 kg.

Bimodal high-density polyethylene polymer compositions with increased high melt strength and good processability. The compositions comprise a base resin having a density of about 945 kg/m.sup.3 to about 955 kg/m.sup.3, and an ethylene polymer (A) having a density of at least about 968 kg/m.sup.3, in an amount ranging from 45% to 55% by weight and an ethylene polymer (B) having a density lower than the density of polymer (A). The composition has a complex viscosity at a shear rate of 0.01 rad/s ranging from about 200 to 450 kPa.Math.s and a complex viscosity at a shear rate of 100 rad/s ranging from about 1900 to 2500 Pa.Math.s. Articles made from these compositions, such as pipes and fittings achieve long-term oxidative resistance and have a low wall thickness variability while maintaining high production output.

The invention is related to a process for producing modified polyethylene having decreased melt flow rate (5 kg, 190 C.) (MFR). In particular, the present invention is directed to a process in a controlled manner for producing modified polyethylene recyclates having low MFR and low gel content directly by reactive extrusion processing.

A primer mixture intended for crosslinking polyethylene, including at least an initiator of free radicals chosen from organic peroxides, azo compounds or mixtures thereof, wherein the mixture has said free-radical initiator and at least one crosslinking promoter chosen from the cycloalkanes having 5 to 7 carbon atoms, substituted by 1 to 3 vinyl, allyl or isopropenyl groups, the aromatic compounds substituted by 1 to 3 vinyl, allyl or isopropenyl groups, the methacrylate, acrylate and maleimide monomers being multi-substituted, and in that the weight ratio of free-radical initiator to the crosslinking promoter is greater than or equal to 1, and preferably between 1.5 and 4. Also, a method and to a use related to this primer mixture.