摘要:
Provided are catalyst systems, processes for polymerizing one or more olefins, polymers resulting therefrom, and articles prepared from such polymers. The processes comprise contacting under polymerization conditions one or more olefin monomers, preferably propylene, with a catalyst system comprising a transition metal compound and an activator of the formula (1) or (2) as described herein. The polymer compositions described herein exhibit advantageously narrow composition distributions and high melting points in comparison to conventional polymers having the same comonomer content. The polymers described herein exhibit improved properties, e.g., pellet stability, impact properties, heat seal properties, and structural integrity in film and fabricated parts applications.
摘要:
Provided are processes for making polymer compositions, especially those with reduced or no gel formation in lubricating oils as identified by rheological and visual gel tests and which are useful as viscosity modifiers. The processes described herein aim to achieve this objective by adjusting the concentrations of the hydrogen feed(s) in the first and/or second polymerization reaction zones, preferably such that (a) the hydrogen feed concentration in the first polymerization reaction zone is 0.0-1.0 wt %, based on total weight of feed(s) of hydrogen, ethylene monomer, α-olefin comonomer, and solvent into the first polymerization reaction zone, and/or (b) the hydrogen feed concentration in the second polymerization reaction zone is 0.0-0.5 wt %, based on total weight of feed(s) of hydrogen, ethylene monomer, α-olefin comonomer, and solvent into the second polymerization reaction zone.
摘要:
Provided are amorphous ethylene propylene copolymer, compositions thereof, and methods for making same, whereby the copolymer can include of from about 40 wt. % to about 60 wt. % ethylene derived units; and of from about 60 wt. % to about 40 wt. % propylene derived units. The copolymer can be characterized by having no discernable melting point as measured by DSC, an MFRR (MI (21.6 kg; 230° C.)/MI (2.16 kg; 230° C.)) (MI (2.16 kg; 230° C.)) of about 38 or more, a molecular weight distribution (MWD) of from about 1.5 to about 2.5, and a shear viscosity η* at 0.01 rad/sec measured at 70° C. that satisfies the relation |η*|(70° C.; 0.01 rad/sec)>1.2*106*|MFR|−0.77, wherein MFR is the melt flow rate.
摘要:
A polymerization catalyst system and polymerization processes using the catalyst systems are disclosed. The polymerization catalyst systems may include a) a first catalyst compound, and b) a second catalyst compound, wherein the first catalyst compound comprises a biphenyl phenol compound having essentially no hydrogen response.
摘要:
The invention generally provides for methods for controlling polymer properties. In particular, invention provides for methods for controlling the comonomer composition distribution of polyolefins such as ethylene alpha-olefin copolymers by altering at least one or more of the following parameters: the molar ratio of hydrogen to ethylene, the molar ratio of comonomer to ethylene, the partial pressure of ethylene, and the reactor temperature without substantially changing the density and/or the melt index of the copolymer.
摘要:
The present invention is directed to polymer blend compositions for use as viscosity modifiers comprising at least two ethylene-based copolymer components. The viscosity modifiers described herein comprise a first ethylene-based copolymer having an ethylene content of from about 44 to about 52 wt % and/or a heat of fusion of from about 0 to about 15 J/g and a second ethylene-based copolymer having an ethylene content of from about 68 to about 75 wt % and/or a heat of fusion of from about 40 to about 65 J/g. The invention is also directed to lubricant compositions comprising a lubricating basestock and a polymer blend of the invention.
摘要:
The present invention is directed to polymer blend compositions for use as viscosity modifiers comprising at least three ethylene-based copolymer components. The viscosity modifiers described herein comprise a first ethylene-based copolymer having an ethylene content of from about 35 to about 55 wt % and/or a heat of fusion of from about 0 to about 30 J/g, a second ethylene-based copolymer having an ethylene content of from about 55 to about 85 wt % and/or a heat of fusion of from about 30 to about 50 J/g, and a third ethylene-based copolymer having an ethylene content of from about 65 to about 85 wt % and/or a heat of fusion of from about 40 to about 70 J/g. The invention is also directed to lubricant compositions comprising a lubricating basestock and a polymer blend as described herein.
摘要:
A process for the production of an ethylene alpha-olefin copolymer is disclosed, the process including polymerizing ethylene and at least one alpha-olefin by contacting the ethylene and the at least one alpha-olefin with a metallocene catalyst in at least one gas phase reactor at a reactor pressure of from 0.7 to 70 bar and a reactor temperature of from 20° C. to 150° C. to form an ethylene alpha-olefin copolymer. The resulting ethylene alpha-olefin copolymer may have a density D of 0.927 g/cc or less, a melt index (I2) of from 0.1 to 100 dg/min, a MWD of from 1.5 to 5.0. The resulting ethylene alpha-olefin copolymer may also have a peak melting temperature Tmax second melt satisfying the following relation: Tmax second melt>D*398−245.
摘要:
Disclosed are rheology modifiers comprising compositionally disperse polymeric compositions and/or crystallinity disperse polymeric compositions that may be useful in modifying the rheological properties of lubrication fluids, and methods for making such compositions. The compositionally disperse polymeric composition are formed from at least two discrete compositions of ethylene copolymers. The crystallinity disperse polymeric composition are formed from ethylene copolymers having at least two discrete values of residual crystallinity.
摘要:
Provided are ethylene-based copolymers, methods of preparing the same, lubricating oil compositions including the same, methods for preparing such lubricating oil compositions, and end uses for such ethylene-based copolymers and lubricating oil compositions. The ethylene-based copolymers may include less than about 80 wt. % of units derived from ethylene and one or more alpha-olefin comonomers having 3 to 20 carbon atoms. The ethylene-based copolymers have a melting peak (Tm), as measured by DSC, of 80° C. or less, and a polydispersity index of about 2.8 or less. In some embodiments, the ethylene-based copolymers have an intramolecular composition distribution of about 50 wt. % or less and/or an intermolecular composition distribution of about 50 wt. % or less.