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Method for preparing ethylene polymer

An ethylene and polyethylene technology, applied in the field of ethylene polymer preparation, can solve problems such as inability to produce polyethylene, and achieve the effect of good mechanical properties

Active Publication Date: 2015-07-22
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, it is well known that current metallocenes cannot produce medium density polyethylene commercially, especially in slurry ethylene polymerization processes.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] Catalyst preparation

[0021] Add 300kg activated silica gel carrier under nitrogen atmosphere, then add the toluene solution of 1100kg10% MAO, then add 10kg of two (1-butyl-3-methylcyclopentadienyl) zirconium chloride 2LiCl THF The toluene solution was reacted for 1 hour, filtered, washed and dried to obtain a powder with good fluidity.

[0022] polymer preparation

[0023] Add ethylene, hexene, hydrogen, nitrogen and the catalyst prepared in Example 1 into a gas-phase fluidized bed reactor, and react at 88°C and 2.01MPa. The polymerization process parameters are shown in Table 1, and the properties of the obtained polymer are shown in Table 2.

Embodiment 2

[0025] Same as Example 1, the difference is that the test process conditions are different, see Table 1 for details. The polymer performance data are shown in Table 2.

[0026] Table 1

[0027]

Example 1

Example 2

Reactor total pressure (MPa)

2.01

2.01

[0028] Ethylene feeding amount (ton / hour)

9.0

8.4

Ethylene partial pressure (MPa)

1.4

1.6

Catalyst addition amount (kg / hour)

2.5

2.3

Hexene feeding amount (kg / hour)

350

300

Hexene / ethylene (molar ratio)

0.09

0.088

Hydrogen feeding amount (g / hour)

350

320

Hydrogen / ethylene (molar ratio)

0.000088

0.000090

Reaction temperature (°C)

88

86

Dwell time (hours)

3.3

3.4

[0029] Table 2 Polymer Data

[0030]

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PUM

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Abstract

The invention provides a method for preparing an ethylene polymer. The method comprises a step that ethylene and alpha-olefin polymerize in the presence of H2, an inert gas and a supported metallocene catalyst in a single reactor, wherein the polyethylene density is 0.925-0.950g / cm<3>, the polyethylene fusion index is 0.1-10g / 10min, the molecular weight distribution of polyethylene is 2-10, the molar ratio of alpha-olefin to ethylene is 0.05-0.2, the supported catalyst is composed of a metallocene compound supported on a porous supporter and a cocatalyst, the metallocene compound is a bridged or non-bridged organic metal compound and contains one or more eta-ligands, the metal is in Subgroup 4, 5 or 6 in Periodic Table of the Elements, the cocatalyst is methylaluminoxane or modified methylaluminoxane, and the supporter can be an inorganic oxide, an organic oxide, a polymer or a mixture. Medium-density polyethylene can be obtained through utilizing the method provided by the invention, and polyethylene has good mechanical performances, can be used for extrusion molding or injection molding, and can be especially used in the hot water tube field.

Description

technical field [0001] The invention relates to the field of preparation of ethylene polymers, in particular to a method for preparing medium-density ethylene polymers using a metallocene catalyst. Background technique [0002] Metallocene polyethylene resins prepared by metallocene catalysts generally have the characteristics of narrow molecular weight distribution and narrow branch chain distribution. These characteristics bring advantages such as good transparency, good puncture resistance and low heat sealing temperature to metallocene polyethylene resins. . Polyethylene can usually be divided into three types according to its density, low-density polyethylene (density less than 0.925g / cm 3 ), medium density polyethylene (density 0.925 ~ 0.950g / cm 3 ), high-density polyethylene (density greater than 0.950g / cm 3 ). [0003] Medium density polyethylene is obtained by copolymerizing α-olefin and ethylene to control the density during the synthesis process. Because its ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08F210/16C08F4/6592C08F2/34F16L9/12
Inventor 郑刚王伟王良师范国强王洪涛邓晓音王红英
Owner CHINA PETROLEUM & CHEM CORP