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Two-step method for preparing peroxide crosslinked polyethylene pipe

A technology of cross-linked polyethylene and di-tert-butyl peroxide, which is applied in the field of plastic product manufacturing, can solve the problems of poor hygienic performance, difficult operation, fire disaster prevention, etc., and achieve the effect of low resistance

Inactive Publication Date: 2019-01-08
ZHEJIANG MENRED COMFORT SYST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the energy consumption is extremely high, and the pipe wall is affected by the fusion line. During the extrusion process, not only must the material be melted and plasticized well, but also the crosslinking agent must not be decomposed prematurely (scorch), and the operation is difficult. Great, the choice of cross-linking agent According to the book of cross-linking agents, DYBP (2,5, methyl, 2,5, [tert-butyl, peroxy], alkyne-3) is the only one, and its odor is serious , The hygienic performance is poor, the pipe is cross-linked in hot air, the surface thermal oxidation is obvious, and the fire is inevitable;
[0005] Microwave post-crosslinking method is extruded by screw extruder, which can be extruded at high speed, but DYBP must also be used as crosslinking agent, which has serious odor, poor hygienic performance, and the phenomenon of "scorch" cannot be avoided. More conductive materials need to be added, and the performance of the material will drop significantly

Method used

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  • Two-step method for preparing peroxide crosslinked polyethylene pipe
  • Two-step method for preparing peroxide crosslinked polyethylene pipe
  • Two-step method for preparing peroxide crosslinked polyethylene pipe

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] This embodiment example provides a kind of preparation method of peroxide crosslinked polyethylene pipe, such as figure 1 shown, including the following steps:

[0037] (1) Mix 100g of high-density polyethylene (HDPE), 0.40g of di-tert-butyl peroxide (DTBP), and 0.45g of antioxidant 1076 in a closed mixer at no more than 35°C at a stirring speed of 300rpm for 10min, to obtain a blend;

[0038] (2) Put the blend into the hopper of the extruder. In order to ensure that the crosslinking agent does not decompose prematurely and the HDPE does not melt, it is compressed and transported to the die (mold) at a temperature of 125 ° C. The temperature of the die is 230 ° C. , extruding, melting and plasticizing the blend and performing initial cross-linking, the cross-linking degree of the initial cross-linking is 20%;

[0039] (3) Put the blend after the primary crosslinking into a non-resistance, and the temperature is 250°C in a hot environment to complete the postcrosslinki...

Embodiment 2

[0042] The present embodiment provides a kind of preparation method of peroxide crosslinked polyethylene pipe, comprising the following steps:

[0043](1) Mix 100g of high-density polyethylene (HDPE), 0.37g of di-tert-butyl peroxide (DTBP), and 0.4g of antioxidant 1076 in a closed mixer at no more than 35°C at a stirring speed of 200rpm for 12min, to obtain a blend;

[0044] (2) Put the blend into the hopper of the extruder. In order to ensure that the crosslinking agent does not decompose prematurely and the HDPE does not melt, it is compressed and transported to the die (mold) at a temperature of 130°C. The temperature of the die is 220°C. Extrude, melt and plasticize the blend and carry out initial crosslinking, the degree of crosslinking of the initial crosslinking is 17%;

[0045] (3) The blend after the initial crosslinking is put into a non-resistance, and the temperature is 270 ° C in a hot environment to complete the postcrosslinking, and the crosslinking degree of t...

Embodiment 3

[0048] The present embodiment provides a kind of preparation method of peroxide crosslinked polyethylene pipe, comprising the following steps:

[0049] (1) Mix 100 g of high-density polyethylene (HDPE), 0.45 g of di-tert-butyl peroxide (DTBP), and 0.42 g of antioxidant 1076 in a closed mixer at no more than 35 ° C at a stirring speed of 250 rpm for 12 min, to obtain a blend;

[0050] (2) Put the blend into the hopper of the extruder. In order to ensure that the crosslinking agent does not decompose prematurely and the HDPE does not melt, it is compressed and transported to the die (mold) at a temperature of 128°C. The temperature of the die is 240°C. Extrude, melt and plasticize the blend and carry out initial crosslinking, the degree of crosslinking of the initial crosslinking is 23%;

[0051] (3) The blend after the initial crosslinking is put into a non-resistance, and the temperature is 250 ° C in a hot environment to complete the postcrosslinking, and the crosslinking de...

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Abstract

The invention provides a two-step method for preparing a peroxide crosslinked polyethylene pipe. The method adopts two steps of primary crosslinking and post crosslinking; during the process of primary crosslinking, polyethylene is melted, plasticized, molded and partially crosslinked; a machine head can be very short, so that the extrusion resistance is small; continuous extrusion can be carriedout by using a screw extruder; the bulk density of the pipe wall is uniform, so that the scorch phenomenon is avoided; an odorless peroxide crosslinking agent can be used, so that sanitary performanceof pipes is good; the time required by crosslinking is short and the extrusion speed is high; the primary crosslinking is matched with the post crosslinking to jointly construct a long cross-linked interval which enables the crosslinking to be more adequate.

Description

technical field [0001] The invention belongs to a method for manufacturing plastic products, in particular to a two-step method for manufacturing peroxide crosslinked polyethylene pipes. Background technique [0002] The creep resistance and heat resistance of cross-linked high-density polyethylene are significantly improved compared with uncross-linked high-density polyethylene. The pipes made of it are called cross-linked polyethylene (PEX) pipes and are widely used in In the hot and cold water system. There are three kinds of PEX pipes that have been commercialized, namely, PEXa pipe-peroxide cross-linked polyethylene pipe; PEXb pipe-silane cross-linked polyethylene pipe; PEXc pipe-irradiation cross-linked polyethylene pipe. [0003] The manufacture of synchronous cross-linked PEXa pipes is extruded by a plunger extruder. The cross-linking process is completed at the same time as the melting and plasticization of the material and the forming of the tube embryo, which can...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08L23/06C08K5/134C08J3/24
CPCC08J3/24C08J2323/06C08K5/1345
Inventor 于东明陈章成唐清洪程志胡明远徐俊正
Owner ZHEJIANG MENRED COMFORT SYST
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