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:
Extruded, copolymer pellet compositions and methods for making the same. A copolymer pellet composition can have an ethylene content of about 40 wt % to about 50 wt % and a propylene content of about 50 wt % to about 60 wt %, based on total weight of the copolymer, wherein the copolymer has a MFR (230° C./2.16 kg) of from about 3.0 g/10 min and about 25 g/10 min; a MWD (Mw/Mn) of about 2.3 or less; and no measurable melting peak, as measured by DSC.
摘要:
A method of polymerizing olefins comprising combining in one embodiment ethylene and optionally one or more α-olefins with a catalyst composition in a continuous polymerization reactor at a pressure of less than 10,000 kPa; wherein the catalyst composition comprises a hafnocene; and isolating a polyethylene having a density in the range of from 0.930 to 0.975 g/cm3. Also provided is a method of transitioning a continuous polymerization reactor from production of a low density polyethylene to a medium or high density polyethylene. Also provided is a medium to high density polyethylene suitable for injection or rotomolding applications. Also provided is a single catalyst composition suitable for such needs.
摘要:
A method of polymerizing olefins comprising combining in one embodiment ethylene and optionally one or more α-olefins with a catalyst composition in a continuous polymerization reactor at a pressure of less than 10,000 kPa; wherein the catalyst composition comprises a hafnocene; and isolating a polyethylene having a density in the range of from 0.930 to 0.975 g/cm3. Also provided is a method of transitioning a continuous polymerization reactor from production of a low density polyethylene to a medium or high density polyethylene. Also provided is a medium to high density polyethylene suitable for injection or rotomolding applications. Also provided is a single catalyst composition suitable for such needs.
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:
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:
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:
Polymerization catalyst systems including three or more catalyst compounds are provided. Methods for olefin polymerization including the aforementioned catalyst systems are also provided.