Process for production of propylene copolymers
AssigneeBraskem America, Inc.
InventorsRuben Migone, Sehyun Kim
Life of this patent
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Abstract
The properties and the amounts of polymers produced in the second stage of a polymerization process in the presence of propylene and ethylene or other alpha olefin are controlled by the addition of an external electron donor to the second stage polymerization. The dosage of external donor to the second stage polymerization is based on a percentage of the dosage of external donor to a first stage polymerization of propylene in the process. The external donor added to the second stage is either the same as or different from the external donor added to the first stage.
Claims14
A process for producing a propylene copolymer, the process comprising:
- in a first stage comprising at least one polymerization reactor, polymerizing propylene in the presence of a Ziegler-Natta catalyst, wherein a first amount of an external donor is added to the first stage,
- passing a polymerization product from the first stage to a second stage comprising at least one polymerization reactor, and
- polymerizing propylene and ethylene or other alpha olefin, in the presence of the polymerization product, wherein a second amount of an external donor is added to the second stage.
A process for producing a propylene copolymer, the process comprising:
- in a first stage comprising at least one liquid phase reactor, polymerizing propylene in the presence of a Ziegler-Natta catalyst, wherein a first amount of an external donor is added to the first stage,
- passing a polymerization product from the first stage to a second stage comprising at least one gas phase reactor, and
- polymerizing propylene and ethylene or another alpha olefin, in the presence of the polymerization product, wherein a second amount of the external donor and an antistatic inhibitor are added to the second stage,
- the second amount of the external donor being from about 10 percent to about 200 percent of the first amount.
Dependencies are inferred from the claim text.