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    24.
    发明专利
    未知

    公开(公告)号：BR9500391A

    公开(公告)日：1996-06-18

    申请号：BR9500391

    申请日：1995-01-31

    Applicant: UNION CARBIDE CHEM PLASTIC

    Inventor： DANIELL PAUL THEODORE ,  TILSTON MICHAEL WILLIAM ,  SPRIGGS THOMAS EDWARD ,  WAGNER BURKHARD ERIC ,  RAMAMURTHY ARAKALGUD VENKATAPA

    IPC: C08J5/18 ,  C08F2/00 ,  C08F2/34 ,  C08F4/60 ,  C08F4/654 ,  C08F10/00 ,  C08F210/02 ,  C08F297/08 ,  C08L23/08 ,  C08L23/16 ,  C08F4/64

    Abstract: 1. A gas phase process for the production of a polyethylene blend comprising contacting ethylene and at least one alpha-olefin comonomer having 3 to 8 carbon atoms with a magnesium/titanium based catalyst system including an activator and a cocatalyst in each of two fluidized bed reactors connected in series, under polymerization conditions, with the provisos that:(a) the mixture of ethylene copolymer matrix and active catalyst formed in the first reactor in the series is transferred to the second reactor in the series;(b) other than the active catalyst referred to in proviso (a) and the cocatalyst referred to in proviso (e), no additional catalyst is introduced into the second reactor;(c) in the first reactor in which a low melt index copolymer is made:(1) the alpha-olefin is present in a ratio of from 0.01 to from 0.4 mole of alpha-olefin per mole of ethylene;(2) optionally, hydrogen is present in a ratio of from 0.001 to from 0.3 mole of hydrogen per mole of ethylene; and(3) the ethylene partial pressure is at least from 40 pounds per square inch; and(d) in the second reactor in which a high melt index copolymer is made:(1) the alpha-olefin is present in a ratio of from 0.005 to from 0.6 mole of alpha-olefin per mole of ethylene;(2) hydrogen is present in a ratio of from 1 to from 3 moles of hydrogen per mole of ethylene; and(3) diethyl zinc is added in an amount of from 2 to from 40 moles of diethyl zinc per mole of titanium; and(e) additional hydrocarbyl aluminum cocatalyst is introduced into the second reactor in an amount sufficient to restore the level of activity of the catalyst transferred from the first reactor to from the initial level of activity in the first reactor.

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