Polyethylene melt blends for high density polyethylene applications
OwnerMichael G. Harris, Joseph M. Staritainventors
Life of this patent
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Abstract
A polyethylene composition is provided that has a density of about 0.945 to about 0.960 g/cm3 and a melt flow index of about 0.1 to about 0.4. The composition is a melt blend of a linear low density polyethylene resin and/or a linear medium low density polyethylene resin, and a high density polyethylene resin. A feature of the composition is that the resins can independently be virgin, recycled, scrap and/or wide specification resins, and mixtures of these. Methods of producing the compositions and extruded, molded and formed plastic articles manufactured from the compositions are presented.
Claims46
A polyethylene composition comprising a melt blend of a high density polyethylene resin and at least one resin selected from the group consisting of linear low density polyethylene resins, linear medium density polyethylene resins, and mixtures thereof, said resins being present in the melt-blended polyethylene composition in amounts relative to one another such that the composition has a density of about 0.945 to about 0.960 g/cm3, a melt flow index of about 0.1 to about 0.4, and a stress crack resistance of at least 24 hours.
A polyethylene composition comprising a melt blend of
- (a) a high density polyethylene resin selected from the group consisting of a high molecular weight high density polyethylene resin having a density of about 0.941 to about 0.958 g/cm3 and a melt flow index of about 0.01 to about 0.2, a homopolymer high density polyethylene resin having a density of about 0.957 to about 0.970 g/cm3 and a melt flow index of about 0.1 to about 1.5, and mixtures thereof;
- and
- (b) at least one additional polyethylene resin having a melt flow index of about 0.1 to about 1.5 and a density of about 0.920 to about 0.940 g/cm3,
- said polyethylene resins being present in the melt-blended composition in amounts relative to one another such that the composition has a density of about 0.945 to about 0.960 g/cm3, a melt flow index of about 0.1 to about 0.4, and a stress crack resistance of at least 24 hours.
An extruded, molded or formed plastic article comprising a melt blended polyethylene composition that comprises a melt blend of a high density polyethylene resin and at least one resin selected from the group consisting of linear low density polyethylene resins, linear medium density polyethylene resins, and mixtures thereof, said resins being present in the melt-blended polyethylene composition in amounts relative to one another such that the composition has a density of about 0.945 to about 0.960 g/cm3, a melt flow index of about 0.1 to about 0.4, and a stress crack resistance of at least 24 hours.
An extruded, molded or formed plastic article comprising a melt blended polyethylene composition that comprises a high density polyethylene resin selected from the group consisting of a high molecular weight high density polyethylene resin having a density of about 0.941 to about 0.958 g/cm3 and a melt flow index of about 0.01 to about 0.2, a homopolymer high density polyethylene resin having a density of about 0.957 to about 0.970 g/cm3 and a melt flow index of about 0.1 to about 1.5, and mixtures thereof;
- and at least one additional polyethylene resin having a melt flow index of about 0.1 to about 1.5 and a density of about 0.920 to about 0.940 g/cm3, said polyethylene resins being present in the melt-blended composition in amounts relative to one another such that the composition has a density of about 0.945 to about 0.960 g/cm3, a melt flow index of about 0.1 to about 0.4, and a stress crack resistance of at least 24 hours.
An extruded, molded or formed pipe and/or pipe fitting comprising a melt blended polyethylene composition that comprises a melt blend of a high density polyethylene resin and at least one resin selected from the group consisting of linear low density polyethylene resins, linear medium density polyethylene resins, and mixtures thereof, said resins being present in the melt-blended polyethylene composition in amounts relative to one another such that the composition has a density of about 0.945 to about 0.960 g/cm3, a melt flow index of about 0.1 to about 0.4, and a stress crack resistance of at least 24 hours.
An extruded, molded or formed pipe and/or pipe fitting comprising a melt blended polyethylene composition that comprises a high density polyethylene resin selected from the group consisting of a high molecular weight high density polyethylene resin having a density of about 0.941 to about 0.958 g/cm3 and a melt flow index of about 0.01 to about 0.2, a homopolymer high density polyethylene resin having a density of about 0.957 to about 0.970 g/cm3 and a melt flow index of about 0.1 to about 1.5, and mixtures thereof;
- and at least one additional polyethylene resin having a melt flow index of about 0.1 to about 1.5 and a density of about 0.920 to about 0.940 g/cm3, said polyethylene resins being present in the melt-blended composition in amounts relative to one another such that the composition has a density of about 0.945 to about 0.960 g/cm3, a melt flow index of about 0.1 to about 0.4, and a stress crack resistance of at least 24 hours.
A method for producing a polyethylene composition, comprising melt blending together a sufficient amount of a high density polyethylene resin and a sufficient amount of at least one additional resin selected from the group consisting of linear low density polyethylene resins, linear medium density polyethylene resins, and mixtures thereof, to produce a melt-blended composition having a density of about 0.945 to about 0.960 g/cm3, a melt flow index of about 0.1 to about 0.4, and a stress crack resistance of at least 24 hours.
A method for producing a polyethylene composition, comprising melt blending together a sufficient amount of a high density polyethylene resin selected from the group consisting of a high molecular weight high density polyethylene resin having a density of about 0.941 to about 0.958 g/cm3 and a melt flow index of about 0.01 to about 0.2, a homopolymer high density polyethylene resin having a density of about 0.957 to about 0.970 g/cm3 and a melt flow index of about 0.1 to about 1.5, and mixtures thereof;
- and a sufficient amount of at least one additional polyethylene resin having a melt flow index of about 0.1 to about 1.5 and a density of about 0.920 to about 0.940 g/cm3, to produce a melt-blended composition having a density of about 0.945 to about 0.960 g/cm3, a melt flow index of about 0.1 to about 0.4, and a stress crack resistance of at least 24 hours.
Dependencies are inferred from the claim text.