US 5,330,951 AGranted

Catalyst composition for polymerizing alpha-olefin

AssigneeMobil Oil Corporation

InventorsRobert I. Mink, Thomas E. Nowlin

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Abstract

The catalyst of the invention is useful in preparing high density polymers of controlled molecular weight distribution. A supported alpha-olefin polymerization catalyst composition of this invention is prepared in a multi-step process. In the first step, a mixture of a solid, porous carrier having reactive --OH groups and a non-polar solvent is contacted with at least one organomagnesium compound of the formula R.sub.m Mg R'.sub.n (I) where R and R' are the same or different C.sub.4 -C.sub.12 alkyl groups, m and n are each 0, 1 or 2, providing that m+n equals the valence of Mg. Subsequently, the mixture of the first step is contacted with 1-butanol. The amount of 1-butanol controls the molecular weight distribution of the The mixture is then contacted with at least one transition metal compound soluble in the non-polar solvent to form a precursor which is activated with a cocatalyst selected from the group consisting of diisobutyl aluminum hydride or triethylaluminum (TEAL) (sometimes referred to as an activator, and the words activator and cocatalyst may be used interchangeably herein.)

Claims26

Dependent claims

A process for preparing a supported alpha-olefin polymerization catalyst composition which comprises the steps of:

i) providing a slurry of a solid, porous carrier having silanol groups and a non-polar solvent to form a slurry of step (i), wherein the non-polar solvent is one in which an organomagnesium compound is soluble,
ii) contacting the slurry of step (i) with at least one organomagnesium compound having the formula
R.sub.m Mg R'.sub.n (I)
where R and R' are the same or different C.sub.4 -C.sub.12 alkyl groups, m and n are each 0, 1 or 2, provided that m+n is equal to the valence of Mg and thereby producing at least one alkane selected from the group consisting of R.sub.m H and R.sub.n 'H, wherein R.sub.m and R.sub.n ' are as defined above;
where sufficient magnesium compound is used to react with the carrier hydroxyl groups (OH) at a Mg/OH ratio of 1.0,
iii) adding to the slurry of step (ii) an amount of 1-butanol, wherein the amount of 1-butanol provides a 1-butanol:Mg molar ratio of 0.1 to 0.40, to control flow ratio of polymerization product and to maintain flow ratio in a range of 20 to 17, and thereby forming a slurry of step (iii);
iv) contacting the slurry of step (iii) with at least one titanium metal compound soluble in the non-polar solvent to provide a Ti:Mg ratio of 0.5 to 2.0, and
v) combining the product of step (iv) with an activating amount of diisobutylaluminum hydride.

5 more elements

Dependencies are inferred from the claim text.