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US 6,472,484 B1Granted
Processes for producing polyolefin composition
AssigneeMitsui Chemicals, Inc.
InventorsShinji Abe, Tomohiro Arase, Satoru Ohtani, Shotaro Matsuda
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AssigneeMitsui Chemicals, Inc.
InventorsShinji Abe, Tomohiro Arase, Satoru Ohtani, Shotaro Matsuda
Estimating the term…
The present invention provides a method for producing a polyolefin composition having a narrow composition distribution and is characterized in that when at least two olefins are copolymerized in the presence of a transition metal compound catalyst using at least two gas phase fluidized bed reactors, a saturated aliphatic hydrocarbon is allowed to exist in each reactor in a concentration from 0.1 to 30 mol %, and the ratio of the concentration (C2) of a saturated aliphatic hydrocarbon in a reactor of a second stage to the concentration (C1) of a saturated aliphatic hydrocarbon in a reactor of a first stage (C2/C1) is 0.13 or more. Further, the present invention provides a method for producing a polyolefin composition by multi-stage polymerization, which can prevent sheeting in the reactor and can give a polyolefin composition stably with high productivity, and is characterized in that a saturated aliphatic hydrocarbon is allowed to exist in a transport line for transporting a polymer particle extracted from a fluidized bed reactor in the previous stage to a fluidized bed reactor in the subsequent stage at a concentration from 0.1 to 30 mol %.
A method of producing a polyolefin composition comprising copolymerizing at least two olefins selected from ethylene or α-olefins having 3 to 20 carbon atoms using at least two gas phase fluidized bed reactors in the presence of a transition metal compound catalyst, wherein copolymerization of the reactor in a second or later stage is conducted in the presence of a copolymer produced in the previous stages, and wherein a saturated aliphatic hydrocarbon exists in each reactor in a concentration from 0.1 to 30 mol %, and the ratio of the concentration (C2) of a saturated aliphatic hydrocarbon in a reactor of a second stage to the concentration (C1) of a saturated aliphatic hydrocarbon in a reactor of a first stage (C2/C1) is 0.13 or more.
A method of producing a polyolefin composition comprising polymerizing or copolymerizing at least one olefin selected from ethylene and α-olefins having 3 to 20 carbon atoms using at least two gas phase fluidized bed reactors, wherein a saturated aliphatic hydrocarbon is allowed to exist in a transport line for transporting a polymer particle extracted from a fluidized bed reactor in the previous stage to a fluidized bed reactor in the subsequent stage, and the concentration of a saturated aliphatic hydrocarbon in the corresponding transport line is in the range from 0.1 to 30 mol %.
Dependencies are inferred from the claim text.