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US 8,501,892 B2Granted
Propylene ethylene polymers and production process
AssigneeExxonMobil Chemical Patents Inc.
InventorsSudhin Datta, Bruce A. Harrington, Weiguo Hu, Periagaram S. Ravishankar, George Rodriguez
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Abstract
Ethylene propylene copolymers, substantially free of diene, are described. The copolymers will have a uniform distribution of both tacticity and comonomer between copolymer chains. Further, the copolymers will exhibit a statistically insignificant intramolecular difference of tacticity. The copolymers are made in the presence of a metallocene catalyst.
Claims16
A copolymer prepared by a process comprising:
- a) polymerizing propylene and ethylene comonomers in a solution process at a reaction temperature at or above 60° C., with a polymerization catalyst complex comprising:
- i) an organometallic Group 4 transition metal compound;
- and
- ii) an activating cocatalyst, wherein said catalyst complex is capable of producing stereospecific polypropylene;
- and
- b) recovering the propylene copolymer,
- wherein the copolymer comprises units derived from propylene in an amount greater than or equal to 75 weight percent, and units derived from ethylene in an amount of from 5 to 25 weight percent, and
- wherein the copolymer has
- (i) a melting point of from greater than 35° C. to less than 110° C.,
- (ii) a weight average molecular weight of:
- Mw>6.10*P*e(3370/T)
- wherein:
- Mw=the weight average molecular weight
- T=the polymerization reaction temperature in degrees Kelvin
- P=the steady state propylene concentration in the polymerization reaction zone in moles per liter, and
- (iii) an elongation of greater than 1000%.
13 more elements
A copolymer prepared by a process comprising:
- a) polymerizing propylene and ethylene comonomers in a solution process at a reaction temperature at or above 60° C., with a polymerization catalyst complex comprising:
- i) an organometallic Group 4 transition metal compound;
- and
- ii) an activating cocatalyst, precursor ionic compound comprising a halogenated tetra-aryl-substituted Group 13 anion wherein each aryl substituent contains at least two cyclic aromatic rings,
- wherein said catalyst complex is capable of producing stereospecific polypropylene;
- and
- b) recovering the copolymer,
- wherein the copolymer comprises units derived from propylene in an amount greater than or equal to 75 weight percent, and units derived from ethylene in an amount of from 5 to 25 weight percent, and
- wherein the copolymer has
- (i) a melting point of from greater than 35° C. to less than 110° C.,
- (ii) a weight average molecular weight of:
- Mw>6.10*P*e(3370/T)
- wherein:
- Mw=the weight average molecular weight
- T=the polymerization reaction temperature in degrees Kelvin
- P=the steady state propylene concentration in the polymerization reaction zone in moles per liter, and
- (iii) a tensile strength greater than 300 psi.
14 more elements
Dependencies are inferred from the claim text.