In-reactor polymer blends
AssigneeExxonMobil Chemical Patents Inc.
InventorsKevin R. Squire, Charles J. Ruff, Cesar A. Garcia-Franco, Peijun Jiang
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Abstract
This invention relates to in-reactor polymer blends comprising at least 60 mole % of propylene and from 0.01 to 10 mole % of at least one diene selected from the group of C6 to C12 α,ω-diene, norbornadiene, vinyl norbornene and mixtures thereof with the balance being ethylene. The blend comprises first and second polymers having different crystallinities and or different Tg's.
Claims14
An in-reactor polymer blend comprising at least 80 mole % of ethylene and from 0.01 to 10 mole % of at least one diene selected from the group consisting of norbornadiene, vinyl norbornene, C6 to C12 α,ω-dienes, and mixtures thereof with the balance being an alpha-olefin selected from the group consisting of propylene, butene, pentene, hexene, and mixtures thereof wherein the blend comprises first and second polymers having different crystallinities in which at least the second polymer comprises at least one branch of the first polymer having 8 or more carbon atoms per 10,000 carbon atoms of the in-reactor blend as observed by 13C NMR, wherein the blend has the following properties:
- (a) a first melting temperature of 70° C. or more and a first Tg of 20° C. or less as determined by Differential Scanning Calorimetry;
- (b) a second melting temperature at least 20° C. different than the first melting temperature as determined by Differential Scanning Calorimetry or a second Tg at least 20° C. different than the first Tg as determined by Differential Scanning Calorimetry;
- (c) at least one branch point per 10,000 carbon atoms, as determined by Carbon 13 NMR;
- and
- (d) a critical relaxation exponent, n, of greater than 0 and less or equal to 0.8.
A process for producing an in-reactor polymer blend, the process comprising:
- (i) contacting a first monomer composition comprising propylene, from 0.01 to 10 mole % of one or more dienes selected from the group consisting of C6 to C12 α,ω-dienes, norbornadiene, vinylnorbornene, and mixtures thereof and optionally ethylene in a first polymerization stage with a metallocene first catalyst which is capable of polymerizing said first monomer composition to produce a first polymer and which is also capable of incorporating said diene into the first polymer such that the product of the first polymerization stage is a propylene-containing first polymer comprising more than one olefinic unsaturation per chain and from 0.1 to 10 mole % diene;
- and
- (ii) contacting at least part of the product of the first polymerization stage with a second monomer composition comprising propylene and optionally ethylene in a second polymerization stage with a second catalyst which is capable of polymerizing said second monomer composition to produce a second polymer and which is also capable of incorporating branches of said first polymer onto said second polymer at said olefinic unsaturation, wherein said second monomer composition has different ethylene concentration than the first monomer composition and wherein the partial pressure of said second monomer composition is kept below 1000 kPa during said second polymerization stage.
A process for producing an in-reactor polymer blend, the process comprising:
- (i) contacting a first monomer composition comprising ethylene, from 0.01 to 10 mole % of one or more dienes selected from the group consisting of C6 to C12 α,ω-dienes, norbornadiene, vinylnorbornene, and mixtures thereof and optionally propylene, butene, pentene hexene or mixtures thereof in a first polymerization stage with a metallocene first catalyst which is capable of polymerizing said first monomer composition to produce a first polymer and which is also capable of incorporating said diene into the first polymer such that the product of the first polymerization stage is an ethylene-containing first polymer comprising more than one olefinic unsaturation per chain and from 0.1 to 10 mole % diene;
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- (ii) contacting at least part of the product of the first polymerization stage with a second monomer composition comprising propylene and optionally ethylene in a second polymerization stage with a second catalyst which is capable of polymerizing said second monomer composition to produce a second polymer and which is also capable of incorporating branches of said first polymer onto said second polymer at said olefinic unsaturation, wherein said second monomer composition has different ethylene concentration than the first monomer composition.
Dependencies are inferred from the claim text.