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US 5,330,950 AGranted
Mixed Ziegler and chromium catalyst and process for preparing a broad molecular weight distribution HDPE
AssigneeMobil Oil Corporation
InventorJohn T. T. Hsieh
Life of this patent
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Abstract
Ethylene polymers or copolymers having very broad molecular weight distributions in a broad range of melt-indicies are produced by using mixtures of MgO-supported Ziegler catalyst and a chromium oxide catalyst in which the usual poisoning of the catalysts does not occur.
Claims15
A catalyst system for production of ethylene polymerization products, having a density of 0.94 to 0.97 and I.sub.21 /I.sub.2 ratio (MFR) ranging from about 140 to about 200 comprising two catalyst components
- wherein a first of said two catalyst components comprises an aluminum component and a titanium component on a magnesium oxide support;
- and wherein a second of said two catalyst components comprises a chromium compound on an inert support;
- wherein a weight ratio of said second of said two catalyst components to said first of said two catalyst components ranges from 3:1 to 15:1 and
- wherein the weight ratio provides said catalyst which gives a broader molecular weight distribution (MWD) than either of said two catalyst components alone.
1 more element
The catalyst of claim 5,
- wherein said first of said two catalyst components comprises an aluminum component, which is R.sub.3 Al wherein R is alkyl of 1 to 6 carbon atoms and a titanium component which is a tetravalent titanium compound on said magnesium oxide support;
- and
- wherein said second of said two catalyst components comprises a chromium compound and a titanium compound.
The catalyst of claim 7, wherein said organic acid is (lower alkoxy-substituted) benzoic acid.
Dependencies are inferred from the claim text.