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A Composite Catalyst for the Preparation of Broad/Bimodal Distribution High-Density Polyethylene

A high-density polyethylene and composite catalyst technology, which is applied in the production of bulk chemicals, etc., can solve the problems of poor processing performance, inability to achieve a balance between processing performance and strength, and low branching degree of high molecular weight parts.

Active Publication Date: 2018-02-09
ZIBO XINSU CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The melt blending method is to blend two resins with different molecular weights by melting. This method has the problems of poor uniformity and high operating costs; Two or more polymerization reactors with different concentrations of chain transfer agents are connected in series. In this polymerization process, the reactor with less hydrogen addition produces high molecular weight polymers, and the reactor with more hydrogen addition produces low molecular weight polymers. Polymers, resulting in broad / bi-distributed polymers
This method also has the problem of high operating costs, and the operation is more complicated; the single-reactor composite catalyst method uses two catalysts with different active centers to prepare ethylene polymers with a wider molecular weight distribution due to different chain termination speeds.
[0003] The molecular weight distribution of the polymer obtained by single-site catalyst (SSC) is narrow, the branch chain distribution is uniform, and the mechanical properties are good, but the processing performance is poor due to the narrow molecular weight distribution. By compounding with other catalysts, the single-site catalyst polymerization can be improved processing performance
[0004] There have been reports on the compound use of traditional Ziegler-Natta catalysts and single-site catalysts, such as WO99 / 03899 of Mobil Corporation. This type of catalyst has much better copolymerization performance than Ziegler-Natta catalysts due to metallocene catalysts, and Ziegler -The molecular weight of the polymer obtained by the Natta catalyst is relatively large, resulting in a very low degree of branching in the high molecular weight part of the obtained resin, or even no branching, while the low molecular part is highly branched. This material cannot achieve the processing performance and strength. Balanced, did not achieve the desired compounding effect

Method used

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  • A Composite Catalyst for the Preparation of Broad/Bimodal Distribution High-Density Polyethylene
  • A Composite Catalyst for the Preparation of Broad/Bimodal Distribution High-Density Polyethylene

Examples

Experimental program
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Effect test

Embodiment 1

[0059] Catalyst preparation

[0060] Under a nitrogen atmosphere, add 200ml of ethanol and 5.7g of magnesium ethoxide into a 500ml four-port glass reactor, start stirring, raise the temperature to 60°C, and feed CO into the magnesium ethoxide / ethanol suspension 2 Until the magnesium ethoxide solid is completely dissolved, a carbonated magnesium compound solution is obtained. The value of X is 2.0.

[0061] Add 35 g of dehydroxylated granular silica gel (Davison955) that has been calcined at 600° C. for 4 hours to the above-mentioned carbonated magnesium compound solution, stir and react at 60° C. for 1 hour, then evaporate ethanol under stirring at 85° C. until the obtained solid The particles are fully dry and can flow freely, and then the solid particles are washed 3 times with 100ml / time of hexane, then the temperature is raised to 95°C, and CO2 is removed at 95°C 2 1 hour, then ramp to 140°C over 1 hour, CO removal at 140°C 2 4 hours, CO 2 It is completely decomposed a...

Embodiment 2

[0067] Catalyst preparation

[0068] Except that the metallocene catalyst compound is (tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconium dichloride, others are as in Example 1.

[0069] Ethylene polymerization

[0070] Polymerization conditions are as in Example 1.

Embodiment 3

[0072] Catalyst preparation

[0073] The addition of metallocene catalyst compound (pentamethylcyclopentadienyl) (n-propyl cyclopentadienyl) zirconium dichloride solution is 15ml (1.0mol / l toluene solution), and the MAO solution addition is 37.5 Except ml, others are as embodiment 1.

[0074] Ethylene polymerization

[0075] Polymerization conditions are as in Example 1.

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Abstract

A kind of composite catalyst that the present invention is used to prepare wide / bimodal distribution high-density polyethylene refers to that a kind of Ziegler-Natta catalyst component and structural formula are that the metallocene catalyst compound of CpACpBMXn is supported on the inert support material, obtains Free-flowing catalyst particles. The Ziegler-Natta catalyst component is obtained by contacting a magnesium alkoxide compound with a structural formula of Mg(OR1)(OR2) as a catalyst magnesium source and a titanium compound with a structural formula of TiXm(OR3)4-m. The composite catalyst of the present invention has high catalytic activity and good polymerization kinetics, and the polymer obtained by polymerization has good mechanical properties and processability, the polymer powder is spherical, the fine powder content is very low, and the bulk density High, good fluidity, good device operation performance.

Description

technical field [0001] The invention relates to a composite catalyst for preparing wide / bimodal distribution high-density polyethylene and a preparation method thereof. Background technique [0002] Broad / bimodal molecular weight distribution polymers, especially polyethylene, can balance good mechanical properties and processing properties, and have been widely used in recent years. Methods for preparing polyethylene with molecular weight broad / bimodal molecular weight distribution include melt blending method, staged reaction method and reactor reaction method. The melt blending method is to blend two resins with different molecular weights by melting. This method has the problems of poor uniformity and high operating costs; Two or more polymerization reactors with different concentrations of chain transfer agents are connected in series. In this polymerization process, the reactor with less hydrogen addition produces high molecular weight polymers, and the reactor with m...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08F10/02C08F210/02C08F210/14C08F4/6592
CPCY02P20/52
Inventor 张志传苏光马丽军赵晓燕姜志强
Owner ZIBO XINSU CHEM