Process to produce enhanced melt strength ethylene/alpha-olefin copolymers and articles thereof

Patent metadata

Field	Value
Publication number	US-9908956-B2
Application number	US-201615216473-A
Country	US
Kind code	B2
Filing date	Jul 21, 2016
Priority date	Mar 28, 2011
Publication date	Mar 6, 2018
Grant date	Mar 6, 2018

Abstract

An ethylene/α-olefin copolymer comprising units derived from ethylene; and units derived from at least one α-olefin; wherein the ethylene/α-olefin copolymer has a density in the range of from 0.90 to 0.94 g/cc; a melt index (I 2 ) in the range of from 0.05 to 50 dg/min; an Mw/Mn of from 3 to 5; and from 300 to 500 vinyl unsaturations per 1,000,000 carbon atoms in the ethylene/α-olefin copolymer is provided. Also provided is a process for producing an ethylene/α-olefin copolymer comprising: (1) polymerizing ethylene and one or more α-olefins in a polymerization reactor; (2) thereby producing an enhanced melt strength ethylene/α-olefin copolymer having from 300 to 500 vinyl unsaturation units per 1,000,000 carbon atoms, a density in the range of from 0.90 to 0.94 g/cc; a melt index (I 2 ) in the range of from 0.05 to 50 dg/min; and a Mw/Mn of from 3 to 5.

First claim

We claim:

1. An ethylene/α-olefin copolymer comprising:
units derived from ethylene; and
units derived from at least one α-olefin;
wherein the ethylene/α-olefin copolymer has a density in the range of from 0.90 to 0.94 g/cc; a melt index (I 2 ) in the range of from 0.05 to 50 dg/min; a Mw/Mn of from 3 to 5; and from 300 to 350 vinyl unsaturations per 1,000,000 carbon atoms in the ethylene/α-olefin copolymer; and a melt strength of at least 3.0 cN measured via capillary rheometer at a standard test temperature of 190° C.

2. A process for producing an ethylene/α-olefin copolymer comprising the steps of:
(1) polymerizing ethylene and one or more α-olefins in a polymerization reactor wherein the ethylene/α-olefin copolymer is produced using a polymerization step occurring at a temperature of at least 205° C. in the presence of a multi-constituent catalyst system comprising a Ziegler-Natta catalyst composition including a magnesium and titanium containing precatalyst and a cocatalyst, wherein said precatalyst has a Ti:Mg ratio between 1.0:40 to 5.0:40 and in the presence of hydrogen from 0.01 to 0.04 mole percent;
(2) thereby producing an enhanced melt strength ethylene/α-olefin copolymer having from 300 to 350 vinyl unsaturation units per 1,000,000 carbon atoms, a density in the range of from 0.90 to 0.94 g/cc; a melt index (I 2 ) in the range of from 0.05 to 50 dg/min; and a Mw/Mn of from 3 to 5; and a melt strength of at least 3.0 cN measured via capillary rheometer at a standard test temperature of 190° C.

3. The process according to any one of claim 2 , wherein the polymerization step occurs in the presence of hydrogen from 0.015 to 0.03 mole percent.

4. The process according to claim 2 , wherein the polymerizing step occurs in a single stage solution reactor.

5. The process according to claim 2 , further comprising adding a primary antioxidant to a product stream produced in the polymerizing step postreactor.

Assignees

• Dow Global Technologies Llc

Inventors

• Effler Lawrence J
• Karjala Teresa P
• Demirors Mehmet
• Savargaonkar Nilesh R
• Bensason Selim
• Zhou Zhe

Classifications

• C08J3/201

  Pre-melted polymers · CPC title

• C08F210/16 Primary

  Copolymers of ethene with alpha-alkenes, e.g. EP rubbers · CPC title

• C08J5/18

  Manufacture of films or sheets · CPC title

• C08L23/0815

  with aliphatic 1-olefins containing one carbon-to-carbon double bond · CPC title

• C08J2323/06

  Polyethene · CPC title