Process for the manufacture of polyethylene or polyethylene-vinyl acetate copolymer

A technology of vinyl acetate and its manufacturing method, which is applied in the field of manufacturing polyethylene or polyethylene-vinyl acetate copolymer, can solve the problems of yellowing of molded objects, reduction of organic peroxide concentration, reduction of polymerization productivity, etc., and achieve Improvement of processing productivity and effect of suppression of increase in fish eyes

Active Publication Date: 2020-01-07
HANWHA TOTAL ENERGIES PETROCHEMICAL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method has the following problems: Although it works temporarily to reduce the fish eyes, the fish eyes in the form of polymers filtered by the filter remain and continue to be heated to decompose and cross-link. After a certain period of time, the fish eyes increase again. The equipment must be stopped for periodic cleaning, and there is a disadvantage that productivity cannot be improved due to the increased extrusion load due to the filter
However, this method has the following problems: it directly reacts with the organic peroxide added as an initiator to produce a side effect of colored by-products, and during extrusion processing, especially during high-temperature processing, the molded product becomes yellow.
In addition, there is a problem that the concentration of the organic peroxide decreases sharply during the polymerization reaction, and the productivity of the polymerization decreases.

Method used

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  • Process for the manufacture of polyethylene or polyethylene-vinyl acetate copolymer
  • Process for the manufacture of polyethylene or polyethylene-vinyl acetate copolymer
  • Process for the manufacture of polyethylene or polyethylene-vinyl acetate copolymer

Examples

Experimental program
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Effect test

Embodiment 1

[0040] Such as figure 1 As shown, polyethylene resin was produced in a tubular reactor with 4 reactors.

[0041] The ethylene monomer and vinyl acetate monomer compressed by the compressor are preheated to the initial temperature of the reactor, and then injected into the tubular reactor containing 4 reaction zones.

[0042] The monomer is divided into the main airflow entering the first reactor and the auxiliary airflow directly entering the second reactor, and the input is at a ratio of 55:45. Use propionaldehyde or propylene as the molecular weight regulator, and inject the main airflow and auxiliary airflow at a ratio of 50:50. The injection amount of the molecular weight regulator is shown in Table 2. The type of organic peroxide used as a reaction initiator and the composition ratio of each component are shown in Table 1 below, and the polymerization conditions such as pressure, temperature, and input amount of a molecular weight modifier in each stage of the reaction ...

Embodiment 2

[0052] Production was carried out in the same manner as in Example 1 above, and ethylene and vinyl acetate monomers were mixed and charged in the ratio shown in Table 2 as monomers to produce an ethylene-vinyl acetate copolymer. In the first reactor and the second reactor where the reaction temperature is lower than 230°C, tert-amyl peroxide 2-ethylhexanoate with a half-life temperature of 1 second at 185°C is mixed with tert-butyl-based organic peroxide. The oxides were mixed together at the ratio shown in Table 1 and used. At the stage of granulating the product, SONGNOX-1076 (octadecyl 3-(3,5-di-tert-butyl-4-hydrophenyl) propionate) as an antioxidant was prepared by mixing 400 ppm.

Embodiment 3

[0054] Production was carried out in the same manner as in Example 1 above, and ethylene and vinyl acetate monomers were mixed and charged in the ratio shown in Table 2 as monomers to produce an ethylene-vinyl acetate copolymer. In the first reactor and the second reactor where the reaction temperature is lower than 230°C, tert-amyl peroxide 2-ethylhexanoate with a half-life temperature of 1 second at 185°C is mixed with tert-butyl-based organic peroxide. The oxides were mixed together at the ratio shown in Table 1 and used. At the stage of granulating the product, SONGNOX-1076 (octadecyl 3-(3,5-di-tert-butyl-4-hydrophenyl)propionate) as an antioxidant was prepared at 1200ppm.

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Abstract

The invention provides a method for manufacturing polyethylene or polyethylene vinylacetate copolymer through a high pressure free radical aggregation method. According to the invention, the free radical put into a reactor is limited. In this way, the generation of fisheyes is inhibited during the high temperature processing process of the manufacture polyethylene or polyethylene vinylacetate copolymer resin. The high level appearance quality can be maintained and the productbility can be improved.

Description

technical field [0001] The present invention relates to the manufacture method of polyethylene or polyethylene-vinyl acetate copolymer, relate in more detail to the manufacture of low-density polyethylene or polyethylene-vinyl acetate copolymer by high-pressure free radical polymerization in tubular reactor According to the method, when the polyethylene or polyethylene-vinyl acetate copolymer resin produced in this way is processed at high temperature, the occurrence of fish eyes is suppressed, the high-level appearance quality can be maintained, and the processing productivity can be improved. Background technique [0002] Polyethylene and polyethylene-vinyl acetate copolymer resins produced by high-pressure radical polymerization have excellent transparency and good processability, and are widely used as raw materials for films, sheets, wires, foamed products, injection molded products, etc. . The high-pressure radical polymerization method is roughly divided into two typ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08F110/02C08F210/02C08F218/08C08F2/01C08F4/34
CPCC08F110/02C08F210/02C08F218/08C08F2/01C08F4/34
Inventor 崔然范朴智溶金宰弘崔承必
Owner HANWHA TOTAL ENERGIES PETROCHEMICAL CO LTD
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