Method for preparing long chain branched polyethylene

A long-chain branched polyethylene technology, applied in the field of long-chain branched polyethylene preparation, can solve problems such as melt collapse, product performance decline, and radiation dose reduction, and achieve easy implementation and shear thinning properties. High, low cost effect

Inactive Publication Date: 2011-04-27
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] Commercial polyethylene resins have various excellent properties, but there are deficiencies in melt strength and processability. For example, even at temperatures above the melting point, linear polyethylene melts cannot produce strain hardening, so it is easy to appear during processing. melt collapse and fracture
The problems that this blended foaming material exists are: 1, need to adopt two kinds of polyethylene raw materials of different structures, have both increased the cost of material selection like this, also will carefully control the irradiation dose of linear polyethylene (10-40kGy) simultaneously , so as not to produce gel, which is not conducive to the blending process and product performance; 2. The blended material may also undergo phas

Method used

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  • Method for preparing long chain branched polyethylene
  • Method for preparing long chain branched polyethylene
  • Method for preparing long chain branched polyethylene

Examples

Experimental program
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Embodiment 1

[0029] Get linear low density polyethylene powder (Tianjin Petrochemical, DGH 1875, butene-1 copolymerization, density 0.918g / cm 3 , the melt index is 0.46g / 10min) to obtain pre-irradiated polyethylene after γ-ray irradiation treatment, the irradiation is carried out under air conditions, the absorbed dose is 15kGy, 100g pre-irradiated polyethylene and 900g linear low density polyethylene The powder is mechanically mixed and then melt blended and extruded. The melt blending extrusion is completed in a twin-screw extruder with a screw diameter of 30mm and an aspect ratio of 35.6. The temperature of the extruder from the feeding section to the die is set at 165°C, 180°C, and 190°C in sequence. , 200°C, 200°C, 200°C, 190°C, the rotation speed of the main machine is 300Hz, the feeding rate is 8Hz, and the product is cooled by a circulating water bath and pelletized to complete the preparation process.

[0030] The properties of the obtained long-chain branched polyethylene are sh...

Embodiment 2

[0037] Get the same linear low-density polyethylene powder 50g of Example 1, obtain pre-irradiated polyethylene after gamma ray irradiation treatment, and the irradiation is carried out under air conditions, and the absorbed dose is 15kGy, and the above-mentioned pre-irradiated polyethylene and 900g of linear low-density polyethylene powder is directly pre-mixed and then subjected to reactive extrusion. The reactive extrusion process is the same as in Example 1, and the product properties are shown in Table 1 and Table 2.

Embodiment 3

[0039] Get the same linear low density polyethylene powder 150g of embodiment 1, obtain pre-irradiated polyethylene after gamma ray irradiation treatment, irradiation is carried out under air condition, and absorbed dose is 15kGy, above-mentioned pre-irradiated polyethylene and 850g of linear low-density polyethylene powder is directly pre-mixed and then subjected to reactive extrusion. The reactive extrusion process is the same as in Example 1, and the product properties are shown in Table 1 and Table 2.

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Abstract

The invention provides a method for preparing long chain branched polyethylene. The method comprises the following steps of: (1) irradiating a substrate polyethylene with high-energy electron beams or gamma-rays to obtain pre-irradiated polyethylene, wherein the irradiation dose is 1 to 20OkGy; (2) blending the pre-irradiated polyethylene obtained in the step (1) and the substrate polyethylene and uniformly stirring to obtain a premixture, wherein in the premixture, the pre-irradiated polyethylene accounts for 1 to 99 weight percent and the substrate polyethylene accounts for 99 to 1 weight percent; and (3) performing reaction extrusion on the premixture obtained in the step (2) to prepare the long chain branched polyethylene. The method is simple, feasible and low in cost; and the obtained long chain branched polyethylene has more sensitive shear thinning property and higher melt strength, is applied to multiple kinds of processing technology, has high processability and particularly has good application prospect in the fields of thin films and foaming.

Description

technical field [0001] The invention relates to a method for preparing long-chain branched polyethylene, in particular to a method for preparing long-chain branched polyethylene including pre-irradiation technology. technical background [0002] Commercial polyethylene resins have various excellent properties, but there are deficiencies in melt strength and processability. For example, even at temperatures above the melting point, linear polyethylene melts cannot produce strain hardening, so it is easy to appear during processing. The melt collapses and fractures. Another example is that linear low density polyethylene still has a high viscosity at high shear rates during the film blowing process, which makes the torque, melt temperature and die pressure during processing very large, causing the melt to flow at the die. The obvious relaxation of the film is not conducive to the formation of stable film bubbles when blowing the film. In addition, there are some other defect...

Claims

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Application Information

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IPC IPC(8): C08J3/28C08L23/06
Inventor 蔡传伦乔金樑张晓红高建明赖金梅宋志海张红彬王亚黄源
Owner CHINA PETROLEUM & CHEM CORP
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