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Dual-function catalyst system for preparing branched polyethylene through ethylene in-situ copolymerization and application of system

A technology of bifunctional catalyst and copolymerization catalyst, applied in physical/chemical process catalyst, organic compound/hydride/coordination complex catalyst, bulk chemical production, etc., can solve the problem of poor matching between oligomerization catalyst and copolymerization catalyst , poor catalyst matching, low catalyst activity, etc., to achieve the effects of high polymerization activity, simple preparation method and low catalyst cost

Inactive Publication Date: 2013-03-20
SOUTH CENTRAL UNIVERSITY FOR NATIONALITIES
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Unfortunately, not all bifunctional catalyst systems consisting of non-cene-type early-transition metal catalysts and oligomerization catalysts that can better catalyze the copolymerization of ethylene and α-olefins can successfully catalyze the in-situ copolymerization of ethylene to obtain branched polyethylene. It is necessary to consider whether there is synergy between the two complexes, whether they will interfere with each other, whether there is interference between the main catalyst and the co-catalyst, etc., that is, whether the oligomerization catalyst and the copolymerization catalyst in the bifunctional catalyst system are well matched. it is good
The inventor's laboratory has found through a large number of experiments that when many oligomerization catalysts and copolymerization catalysts form a bifunctional catalyst system, they either only generate oligomers, or only have ethylene homopolymers, or oligomers and homopolymers. Mixture, even the activities of the two catalysts are severely reduced, and there are almost no products, which is the performance of the poor matching of the two catalysts

Method used

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  • Dual-function catalyst system for preparing branched polyethylene through ethylene in-situ copolymerization and application of system
  • Dual-function catalyst system for preparing branched polyethylene through ethylene in-situ copolymerization and application of system
  • Dual-function catalyst system for preparing branched polyethylene through ethylene in-situ copolymerization and application of system

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040] The main catalyst (A1) of the oligomerization catalyst and the main catalyst (B1) of the copolymerization catalyst are as follows respectively, and the co-catalyst is MMAO (modified methyl aluminoxane).

[0041]

[0042] The 100ml polymerization bottle was pumped and baked for 3 times, replaced twice with high-purity nitrogen, and replaced with ethylene gas for the last time. Under 1 atm ethylene atmosphere, add 30ml of solvent toluene, control the reaction temperature at 25°C, add 10mmol of MMAO while stirring, continue After stirring for 10 minutes, add 4 μmol A1 and 1 μmol B1 to start the in-situ polymerization reaction. After 10 minutes of reaction, stop the reaction with 5% hydrochloric acid. The product was washed with hydrochloric acid aqueous solution, water and ethanol respectively, dried in vacuum, and weighed to calculate the activity; the properties and structure of the product were characterized by high-temperature GPC and high-temperature carbon spectrum...

Embodiment 2

[0044] The main catalyst of the oligomerization catalyst and the main catalyst of the copolymerization catalyst are A1 and B1 respectively, and the cocatalyst is MAO (methyl aluminoxane); the molar ratio of A1 and B1 is 2:1, and the polymerization reaction steps are as in Example 1, and other reactions Conditions, polymerization activity and product characterization results are shown in Table 1.

Embodiment 3

[0046] The main catalyst of the oligomerization catalyst and the main catalyst of the copolymerization catalyst are respectively A1 and B1, and the cocatalyst is] Ph3C]+[B(C6F5)4]-; the molar ratio of the sum of the cocatalyst and the main catalyst is 500:1, and the solvent It is hexane, the polymerization reaction steps are as in Example 1, other reaction conditions, polymerization activity and product characterization results are shown in Table 1.

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Abstract

The invention discloses a dual-function catalyst system for preparing branched polyethylene through ethylene in-situ copolymerization and application of the system. The dual-function catalyst system comprises an oligomerization catalyst and a copolymerization catalyst, wherein the oligomerization catalyst and the copolymerization catalyst both comprise main catalysts and cocatalysts; the main catalyst of the oligomerization catalyst is a pyridine bis-imines iron or cobalt complex; the main catalyst of the copolymerization catalyst is a non-cyclopentadienyl trident titanium complex; and the cocatalysts of the oligomerization catalyst and the copolymerization catalyst are the same and both lewis acid. The dual-function catalyst system disclosed by the invention simplifies the production process due to the fact that ethylene is used as an only raw material and high-price alpha-alkene is not needed to be added when the branched polyethylene is prepared, and the branched polyethylene with different structures and different properties can be obtained by regulating the proportion of the two catalysts, and especially, the branching degree is effectively regulated and controlled by changing the proportion and reaction conditions of the catalysts. The dual-function catalyst system has important significance.

Description

technical field [0001] The invention belongs to the technical field of polymer materials and metal organic chemistry, and specifically relates to a bifunctional catalyst system for preparing branched polyethylene by in-situ copolymerization of ethylene and its application. Background technique [0002] Polymer materials are one of the pillar industries of the national economy, among which polyolefin has always been the most important product. According to statistics, the global organic polymer synthetic materials have exceeded 150 million tons. As typical representatives of polyolefins, polyethylene, polypropylene, polystyrene and their corresponding copolymers account for about 75% of synthetic resins. Countries are competing to carry out research on olefin polymerization. [0003] Branched polyethylene has an extremely wide range of uses due to its adjustable structure and excellent performance, and its typical representative is linear low-density polyethylene (LLDPE). L...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08F210/16C08F4/642B01J31/22
CPCY02P20/52
Inventor 谢光勇张翔雷禄张爱清
Owner SOUTH CENTRAL UNIVERSITY FOR NATIONALITIES