Peroxide crosslinking polyethylene tubes and machining method thereof

A technology of cross-linking polyethylene and peroxide, which is used in tubular articles, other household appliances, applications, etc., can solve the problems of low cross-linking degree and weak bending resistance of pipes, and achieve the effect of good swelling performance.

Active Publication Date: 2011-06-15
PETROCHINA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Extruded by a tube extruder and irradiated by electron rays, the degree of crosslinking is relatively low, and the degree of bending resistance of the tube is weak

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] Under the protection of nitrogen, 0.2L of triethylaluminum alkylaluminum was added to 1800L of hexane, and then 100g of Ziegler-Natta catalyst was added. The temperature of the polymerization kettle was raised to 50° C. and stirred for 20 minutes. Add 48 mol of hydrogen to the reaction system, and then feed the mixture of ethylene and propylene. The ethylene pressure is controlled at ≤0.9MPa, and the reaction temperature is controlled at 80°C. When the amount of ethylene added reaches 520Kg, the reaction is stopped. The reactant was filtered and dried to obtain 500Kg of polyethylene product. The average particle size of polyethylene powder is determined to be 220μm, and the bulk density is 0.38g / cm 3 .

[0021] Mix 80Kg of polyethylene powder with 480g of di-tert-butyl peroxide and 240g of antioxidant bisphenol phosphite in a high-speed mixer at room temperature for 10 minutes.

[0022] In the range of 120°C, the above-mentioned mixed material is extruded into a PEX-...

Embodiment 2

[0024] Under the protection of nitrogen, 0.2L triethylaluminum alkylaluminum was added to 1800L linear saturated alkane mixture, and then 120g Ziegler-Natta catalyst was added. The temperature of the polymerization kettle was raised to 50° C. and stirred for 20 minutes. Add 55 mol of hydrogen to the reaction system, and then feed the mixture of ethylene and propylene. The ethylene pressure is controlled at ≤0.9MPa, and the reaction temperature is controlled at 83°C. When the amount of ethylene added reaches 520Kg, the reaction is stopped. The reactant was filtered and dried to obtain 500Kg of polyethylene product. The average particle size of polyethylene powder is determined to be 300μm, and the bulk density is 0.40g / cm 3 .

[0025] Mix 80Kg polyethylene powder with 400g di-tert-butyl peroxide and 240g antioxidant bisphenol phosphite in a high-speed mixer at room temperature for 10 minutes.

[0026] In the range of 150°C, the above-mentioned mixture is extruded into a PEX-...

Embodiment 3

[0028] Under the protection of nitrogen, 0.2L triethylaluminum alkylaluminum was added to 1800L linear saturated alkane mixture, and then 120g Ziegler-Natta catalyst was added. The temperature of the polymerization kettle was raised to 50° C. and stirred for 20 minutes. Add 64 mol of hydrogen to the reaction system, and then feed the mixture of ethylene and propylene. The ethylene pressure is controlled at ≤0.9MPa, and the reaction temperature is controlled at 84°C. When the amount of ethylene added reaches 620Kg, the reaction is stopped. The reactant was filtered and dried to obtain 600Kg of polyethylene product. The average particle size of polyethylene powder was determined to be 260μm, and the bulk density was 0.38g / cm 3 .

[0029] 80Kg polyethylene powder was mixed with 450g di-tert-butyl peroxide and 240g antioxidant distearyl pentaerythritol diphosphite in a high-speed mixer at room temperature for 10 minutes.

[0030] In the range of 180°C, the above-mentioned mixtu...

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Abstract

The invention relates to peroxide crosslinking polyethylene tubes and a machining method thereof. The polyethylene tubes comprise the following components in percentage by mass: 0.5 to 0.6 percent of peroxide di-tert-butyl ether, 0.3 percent of antioxidant and the balance of polyethylene powder, wherein the average particle size distribution of the polyethylene powder is between 200 and 300 micrometers, the bulk density is between 0.35 and 0.40 g / cm<3>, the density is between 0.947 and 0.950 g / cm<3>, and the polyethylene powder has a uniform short-branched chain structure; the crosslinking degree of the peroxide crosslinking polyethylene tubes is more than or equal to 80 percent; and the particle size of the polyethylene powder for forming the tubes by crosslinking can be distributed relatively and reasonably without subsequent crushing, and the same and even higher crosslinking degree can be reached in the crosslinking process under the condition of less peroxides. The polyethylene tubes have high heat-resisting creep properties, high impact resistance, high swelling performance and the like.

Description

Technical field: [0001] The invention relates to a peroxide crosslinked polyethylene pipe material for extrusion molding and a processing method thereof. Background technique: [0002] When polyethylene is mixed with peroxide, in the molten state, the peroxide decomposes to generate free radicals, forming carbon-carbon bonds between polyethylene molecules, and a large number of carbon-carbon bonds between molecules make polyethylene a cross-linked structure. In order to form a three-dimensional network structure, polyethylene resin needs to be heated to produce cross-linking. The peroxide and antioxidant must be fully infiltrated before processing, and then the peroxide cross-linked polyethylene (PEX-a) powder is processed into pipes through a plunger extruder. Pipes processed from low-density polyethylene and linear low-density polyethylene compositions have many defects such as poor thermal creep resistance, poor impact resistance, and poor swelling performance. The cros...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08J3/24C08L23/16C08K5/14C08K5/526C08K5/524C08F210/16B29C47/00B29L23/00
Inventor 张利仁史君王健姜明才刘志军吕洁杨振国孙辉宇焦金华徐丽艳崔勇崔月
Owner PETROCHINA CO LTD
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