Process for the preparation of ethylene (co)polymers
AssigneeHoechst Aktiengesellschaft
InventorsAndreas Heinrich, Ludwig Bohm, Hans-Albrecht Scholz
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Abstract
For the homopolymerization of ethylene or for the copolymerization of ethylene with other 1-olefins, a catalyst is used which comprises a trialkylaluminum compound and the entire product from the reaction of a magnesium alkoxide which is dissolved, suspended or dispersed as a gel in an inert solvent, with a tetravalent transition-metal compound and an organoaluminum compound, washing with an inert solvent and reacting with a halogenated metal compound. A polymer having coarse particles and a high bulk density is obtained.
Claims9
A process for the preparation of an ethylene polymer having a uniform coarse particle shape and high bulk density by polymerizing ethylene or ethylene with up to 10% by weight, based on the total amount of the monomers, of a 1-olefin of the formula R.sup.6 --CH.dbd.CH.sub.2 in which R.sup.6 is a straight-chain or branched alkyl radical having 1 to 12 carbon atoms, in suspension, in solution or in the gas phase, at a temperature of from 20.degree. to 120.degree. C. and at a pressure of from 2 to 60 bar, which comprises carrying out the polymerization in the presence of a catalyst which comprises
- a) the entire product of the components consisting essentially of
- a1) a magnesium alkoxide of the formula I
- Mg(OR.sup.1)(OR.sup.2) (I)
- in which R.sup.1 and R.sup.2 are identical and are an unbranched or branched alkyl radical having 1 to 20 carbon atoms or a --(CH.sub.2).sub.n OR.sup.3 radical where R.sup.3 is an alkyl radical having 1 to 4 carbon atoms and n is an integer from 2 to 6,
- a2) a tetravalent transition-metal compound of the formula II
- M.sup.1 X.sub.m (OR.sup.4).sub.4-m (II)
- in which M.sup.1 is titanium, zirconium or hafnium, R.sup.4 is an alkyl radical having 1 to 9 carbon atoms, X is a halogen atom and m is an integer from zero to 4, and
- a3) an organoaluminum compound of the formula III
- AlR.sup.5.sub.p X.sub.3-p (III)
- in which R.sup.5 is an alkyl radical having 1 to 6 carbon atoms, X is a halogen atom and p is a number from zero to 3, or the reaction product of a trialkylaluminum compound or dialkylaluminum hydride with a diene, in the Mg:M.sup.1 :Al ratio of 1:0.05 to 10:0.01 to 4, and
- a4) a metal halide of the formula IV
- M.sup.2 Cl.sub.4 (IV)
- in which M.sup.2 is titanium, silicon or tin, or BCl.sub.3, in the M.sup.1 :M.sup.2 ratio of from 1:0.2 to 100, the intermediate product of essentially the components a1, a2, and a3 having been reacted with said component a4, and
- b) a trialkylaluminum compound having 1 to 6 carbon atoms in the alkyl radicals or the product of the reaction of a trialkylaluminum compound or dialkylaluminum hydride with a diene.
A method for polymerizing an olefin comprising ethylene, said method comprising the step of polymerizing the olefin in the presence of a catalyst system wherein said catalyst system comprises
- a) the entire product of the components consisting essentially of
- a1) a magnesium alkoxide of the formula I
- Mg(OR.sup.1) (OR.sup.2) (I)
- in which R.sup.1 and R.sup.2 are identical and are an unbranched or branched alkyl radical having 1 to 20 carbon atoms or a --(CH.sub.2).sub.n OR.sup.3 radical where R.sup.3 is an alkyl radical having 1 to 4 carbon atoms and n is an integer from 2 to 6,
- a2) a tetravalent transition-metal compound of the formula II
- M.sup.1 X.sub.m (OR.sup.4).sub.4-m (II)
- in which M.sup.1 is titanium, zirconium or hafnium, R.sup.4 is an alkyl radical having 1 to 9 carbon atoms, X is a halogen atom and m is an integer from zero to 4, and
- a3) an organoaluminum compound of the formula III
- AlR.sup.5.sub.p X.sub.3-p (III)
- in which R.sup.5 is an alkyl radical having 1 to 6 carbon atoms, X is a halogen atom and p is a number from zero to 3, or the reaction product of a trialkylaluminum compound or dialkylaluminum hydride with a diene, in the Mg:M.sup.1 :Al ratio of 1:0.05 to 10:0.01 to 4, and
- a4) a metal halide of the formula IV
- M.sup.2 Cl.sub.4 (IV)
- in which M.sup.2 is titanium, silicon or tin, or BCl.sub.3, in the M.sup.1 :M.sup.2 ratio of from 1:0.2 to 100, the intermediate product of essentially the components a1, a2, and a3 having been reacted with said component a4, and
- b) a trialkylaluminum compound having 1 to 6 carbon atoms in the alkyl radicals or the product of the reaction of a trialkylaluminum compound or dialkylaluminum hydride with a diene.
Dependencies are inferred from the claim text.