Reversible chain-transfer in polyolefin polymerization with pyridyldiamide catalysts

A process of producing ethylene α-olefin copolymers comprising:

• contacting ethylene and a C3 to C10 α-olefin with a transition metal pyridyldiamide catalyst component and an activator, as well as from 10 equivalents to 1000 equivalents relative to the catalyst component of chain transfer agent;
• isolating an ethylene-α-olefin copolymer having a Tm of less than 140° C., a Mw/Mn of less than 2.5, and a weight average molecular weight (Mw) within the range of from 5 kDa to 500 kDa, wherein the contacting first takes place in the absence of the chain transfer agent and ethylene-α-olefin copolymer is first isolated having a Mw/Mn within the range of from 1.5 to 2.5;
• followed by addition of the chain transfer agent and isolation of ethylene-α-olefin copolymer having a Mw/Mn of less than 2.0.

A process of producing ethylene α-olefin copolymers comprising:

• contacting ethylene and a C3 to C10 α-olefin with a transition metal pyridyldiamide catalyst component and an activator, as well as from 10 equivalents to 1000 equivalents relative to the catalyst component of chain transfer agent;
• wherein the contacting first takes place in the absence of the chain transfer agent and ethylene-α-olefin copolymer is first isolated having a weight average molecular weight (Mw) within the range of greater than 200 kDa;
• followed by addition of chain transfer agent and isolation of ethylene-α-olefin copolymer having a Mw of less than 400 kDa, or within a range of from 5 kDa to 200 kDa.

A process of producing ethylene α-olefin copolymers comprising:

• contacting ethylene and a C3 to C10 α-olefin with a transition metal pyridyldiamide catalyst component and an activator, as well as from 10 equivalents to 1000 equivalents relative to the catalyst component of chain transfer agent;
• wherein the contacting first takes place in the absence of chain transfer agent and ethylene-α-olefin copolymer is first isolated having a Mw/Mn within the range of from 1.5 to 2.5;
• followed by addition of the chain transfer agent and isolation of ethylene-α-olefin copolymer having a Mw/Mn of less than 2.0.

A process of producing ethylene α-olefin copolymers comprising:

• contacting ethylene and a C3 to C10 α-olefin with a transition metal pyridyldiamide catalyst component and an activator, as well as from 10 equivalents to 1000 equivalents relative to the catalyst component of diphenyl zinc chain transfer agent;
• isolating an ethylene-α-olefin copolymer having a Tm of less than 140° C., a Mw/Mn of less than 2.5, and a weight average molecular weight (Mw) within the range of from 5 kDa to 500 kDa, wherein the presence of the chain transfer agent increases the activity of the catalyst component by a factor of at least 2 relative to the activity under the same conditions when chain transfer agent is not present.