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Heat treatment of ziegler-Natta catalysts

A catalyst and compound technology, which is applied in the field of heat treatment of magnesium-containing Ziegler-Natta catalyst systems, can solve problems such as reducing the molecular weight of polymers

Inactive Publication Date: 2003-08-27
NOVA CHEM (INT) SA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0011] Generally, in a continuous solution polymerization process of ethylene, higher catalyst activity results in increased ethylene conversion and lower molecular weight (e.g. Mw) of the resulting polymer

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0052] The following examples were carried out in a small scale continuous polymerization plant. Homopolymers or copolymers can be prepared in various embodiments. The catalyst of the present invention was prepared by feeding two of the four components in a first continuous stirred tank reactor. The third and fourth ingredients were added to the outlet of the first reactor or directly into the second continuously stirred reactor. The individual monomers were fed continuously into the second continuous reactor. The operating temperature of the second continuous reactor was about 200°C in the experiments. The temperatures in the first continuous stirred reactor are shown in Table 1 below. In the experiments, the same conditions were used to prepare catalysts for copolymers and homopolymers. For convenience, the catalyst mixing temperatures used for homopolymers and copolymers are listed in the first column. The activity (Kp), density and molecular weight of each catalyst us...

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Abstract

The present invention provides a novel catalyst preparation method to substantially increase the polymer molecular weight in the high temperature solution process. The method utilizes mixing and heating a mixture of Aluminum alkyl / dialkyl Magnesium with a chlorinating compound, prior to reacting with Transition metal and a second Aluminum alkyl activator. This novel catalyst preparation method is designed to significantly increase the molecular weight in ethylene - alpha-olefin copolymerization by about 80% without any significant loss in activity.

Description

technical field [0001] The present invention relates to a method for thermally treating a Ziegler-Natta catalyst system containing magnesium. The catalyst system comprises (i) an alkylaluminum compound and a dialkylmagnesium compound; (ii) an alkyl halide; (iii) a transition metal halide; and (iv) a dioxane Dialkyl aluminum alkoxide mixture. The catalytic system is prepared by mixing the three above-mentioned components, and heat-treating the mixture at a temperature in the range of 30°C-100°C for 2-30 minutes. The resulting catalyst is particularly suitable as a catalyst system for the solution polymerization of olefins, and especially for the polymerization of ethylene copolymers and homopolymers. The catalyst is highly active on both ethylene copolymers and ethylene homopolymers and provides about an 80% gain in the weight average molecular weight of the ethylene copolymers. Background technique [0002] In U.S. Patent 5,589,555 (Zboril et al., issued December 31, 1996...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08F2/06C08F4/658C08F10/00
CPCC08F10/00C08F4/6543C08F4/642
Inventor I·贾比尔
Owner NOVA CHEM (INT) SA