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Method for preparing low crystal point polyethylene by tubular method and low crystal point polyethylene

A technology of polyethylene and polyethylene particles, which is applied in the field of low-crystal point polyethylene and high-pressure preparation of low-crystal point polyethylene by tubular method, which can solve the problems of high waste rate of blown film, complicated solutions, high-end film material production, etc. Achieve the effects of improving printing quality, improving product quality image, and reducing film rupture rate

Active Publication Date: 2021-08-17
CHINA SHENHUA COAL TO LIQUID & CHEM CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] At present, the existing technology is to improve the polyolefin additive or catalyst configuration equipment, so as to produce polyethylene products with excellent performance, and mainly for linear polyethylene products, and through the reaction of high-pressure low-density polyethylene by tubular method, etc. There is no systematic report on the improvement of the operation method and thus the improvement of the crystallization point of the product
In addition, due to many reasons for the high crystal point of polyethylene products, difficult analysis, and complicated solutions, etc., the high crystal point of tubular high-pressure low-density polyethylene products has always been high, resulting in a high waste rate of blown film and cannot be used for high-end products. The problem of film material production has always existed

Method used

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  • Method for preparing low crystal point polyethylene by tubular method and low crystal point polyethylene

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Experimental program
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Effect test

Embodiment 1

[0054] This embodiment is to illustrate the low crystal point polyethylene prepared by the method of the present invention.

[0055] (1) The ethylene monomer is compressed through a compressor; wherein, the filtration accuracy of the pipeline for transporting the ethylene is 1 μm, the content of alkyne in the ethylene monomer is 5 ppm, and the single-cylinder lubricating oil injection amount of the compressor is 2.5 liters / day;

[0056] (2) In the presence of an initiator, the compressed ethylene monomer after step (1) is subjected to an addition polymerization reaction in a reactor; wherein, the initiator is a peroxide, and in the peroxide The content of tert-butyl hydroperoxide is 100ppm; the reaction temperature of the first reaction zone in the reactor is 302°C, and the reaction temperature of the fourth reaction zone is 295°C; the addition polymerization reaction is carried out in the tubular reactor To carry out, the discharge of the tubular reactor is controlled by a p...

Embodiment 2

[0061] This embodiment is to illustrate the low crystal point polyethylene prepared by the method of the present invention.

[0062] (1) Compress ethylene monomer through compressor; Wherein, the filtration precision of the pipeline that transports described ethylene is 1 μm, and the content of alkyne in described ethylene monomer is 5ppm; Compressor single cylinder lubricating oil injection rate is 3 L / day;

[0063] (2) In the presence of an initiator, the compressed ethylene monomer obtained in step (1) is subjected to an addition polymerization reaction in a reactor; wherein, the initiator is a peroxide, and in the peroxide The content of tert-butyl hydroperoxide is 100ppm; increase the reaction temperature of the first reaction zone, be controlled at 305°C, reduce the reaction temperature of the fourth reaction zone, be controlled at 290°C; the addition polymerization reaction is carried out in a tubular reactor The discharge of the tubular reactor is controlled by a puls...

Embodiment 3

[0068] This embodiment is to illustrate the low crystal point polyethylene prepared by the method of the present invention.

[0069] The polyethylene product was prepared in the same manner as in Example 2, except that the reaction pulse level was adjusted to 10, and the reaction pulse period was adjusted to 90 seconds.

[0070] The properties of the prepared polyethylene products are shown in Table 1.

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Abstract

The invention relates to the technical field of polyethylene preparation, and discloses a high-pressure tubular method for preparing low-crystal point polyethylene and the low-crystal point polyethylene. Wherein, the method includes: (1) compressing ethylene monomer through a compressor; wherein, the filtration accuracy of the pipeline filter through which the ethylene monomer flows is ≤1 μm; the content of alkyne in the ethylene monomer is ≤10ppm (2) Under the condition that the initiator exists, the compressed ethylene monomer obtained in step (1) is subjected to an addition polymerization reaction; wherein, the initiator is a peroxide, and the tert-butyl peroxide in the peroxide The content of hydrogen oxide is less than or equal to 200ppm; (3) separating the product obtained in step (2); (4) extruding and granulating the separated molten polyethylene to obtain polyethylene particles. The polyethylene prepared by the method of the invention can improve the mechanical properties of the polyethylene film by controlling the crystal point, increase the blown film forming rate, and reduce the film breaking rate.

Description

technical field [0001] The invention relates to the technical field of polyethylene preparation, in particular to a method for preparing low-crystal-point polyethylene by a tubular method under high pressure and low-crystal-point polyethylene. Background technique [0002] The production of high-pressure low-density polyethylene generally has two production processes: tubular method and kettle method. Among them, the tubular method has the characteristics of large processing capacity, low energy consumption, low equipment failure rate and long operation cycle. Commonly used by everyone. [0003] The tubular high-pressure low-density polyethylene device, because of its process characteristics, the products prepared are mainly used to produce film materials (greenhouse film, mulch film and shrink film, etc.), and the production of film materials is the most concerned and has the greatest impact on product quality It is the crystal point of the raw polyethylene, which affects ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08F110/02C08F2/00
CPCC08F110/02C08F2/00
Inventor 黄起中徐海波马雷孙爱光姜兴剑孙浩
Owner CHINA SHENHUA COAL TO LIQUID & CHEM CO LTD