A HDPE flame-retardant pipe for power communication and preparation method thereof

Abstract

The present invention relates to a HDPE flame retardant pipe for power communication and a preparation method thereof, belonging to the technical field of flame retardant pipes. A HDPE flame retardant pipe for power communication, characterized in that: the HDPE flame retardant pipe comprises a plurality of power communication cables, a shielding layer and an anti-oxidation layer, the shielding layer wraps the plurality of power communication cables, the anti-oxidation layer is attached to the outer surface of the shielding layer, and a wear-resistant flame retardant layer is provided on the outer surface of the anti-oxidation layer, and the wear-resistant flame retardant layer is made of high-density polyethylene, a compatibilizer and an organic / inorganic hybrid flame retardant as raw materials; the present invention can effectively protect the HDPE flame retardant pipe, and has anti-oxidation and corrosion resistance, and excellent mechanical strength; the organic / inorganic hybrid flame retardant enables the polyethylene composite material to form a stable carbon layer during the combustion process, blocking oxygen and heat, while absorbing a large amount of heat, reducing the surface temperature of the material, effectively preventing the spread of fire, and achieving a flame retardant effect.

Description

Technical Field

[0001] The invention belongs to the technical field of flame-retardant pipes and relates to a HDPE flame-retardant pipe for power communication and a preparation method thereof. Background Art

[0002] The outer layer material of existing flame retardant pipes is generally modified by composite modification of HDPE and polypropylene. The addition of polypropylene can improve the mechanical properties of the material, such as strength and toughness. This is very necessary for the outer layer material of flame retardant pipes because it needs to withstand certain mechanical stress. However, HDPE has a low oxygen index and is a flammable polymer material. It has great limitations in use and research, and is very easy to burn when exposed to heat and discharge. Flame retardant purposes are achieved by adding flame retardants. Flame retardants are roughly divided into halogen flame retardants and halogen-free flame retardants. The flame retardant effect of a single flame retardant is not ideal. Different flame retardant systems have their own advantages and disadvantages. The combination of flame retardants with different mechanisms can improve the flame retardant effect of the material.

[0003] Expandable graphite contains a large amount of carbon, which makes it extremely heat-resistant and corrosion-resistant. When HDPE material is directly mixed with expandable graphite, due to the difference in surface energy between the two, insufficient interfacial adhesion may occur, and the uneven distribution of expandable graphite in the HDPE material system will also affect its flame retardant effect. Summary of the invention

[0004] The purpose of the present invention is to provide a HDPE flame retardant pipe for power communication and a preparation method thereof. The present invention can effectively protect the HDPE flame retardant pipe, and has anti-oxidation and corrosion resistance as well as excellent mechanical strength; the organic / inorganic hybrid flame retardant enables the polyethylene composite material to form a stable carbon layer during the combustion process, blocking oxygen and heat, while absorbing a large amount of heat, reducing the surface temperature of the material, effectively preventing the spread of fire, and achieving a flame retardant effect.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A HDPE flame-retardant pipe for power communication comprises a plurality of power communication cables, a shielding layer and an anti-oxidation layer, wherein the shielding layer wraps the plurality of power communication cables, the anti-oxidation layer is adhered to the outer surface of the shielding layer, and a wear-resistant flame-retardant layer is provided on the outer surface of the anti-oxidation layer, wherein the wear-resistant flame-retardant layer is made of high-density polyethylene, a compatibilizer and an organic / inorganic hybrid flame retardant as raw materials.

[0007] As a preferred technical solution of the present invention, an elastic object is provided between the power communication cable and the shielding layer; the material of the elastic object is elastic resin.

[0008] As a preferred technical solution of the present invention, the shielding layer includes a stainless steel tube, an aramid fiber sheath and a metal woven mesh layer; the aramid fiber sheath covers the stainless steel tube; the metal woven mesh layer is arranged on the outer wall of the aramid fiber sheath, and the material of the metal woven mesh layer is one or more of copper alloy, aluminum alloy and magnesium alloy.

[0009] The invention discloses that the wear-resistant flame-retardant layer comprises the following components by weight: 80-90 parts of high-density polyethylene, 5-7 parts of a compatibilizer and 15-20 parts of an organic / inorganic hybrid flame retardant; the compatibilizer is a styrene-butadiene-glyceryl methacrylate copolymer.

[0010] As a preferred technical solution of the present invention, the preparation method of the organic / inorganic hybrid flame retardant comprises the following steps:

[0011] Step S1: placing expandable graphite, anhydrous ethanol and 3,4-dihydroxyaniline in a reaction kettle for ultrasonic mixing, adding a mixed monomer, heating and stirring, centrifuging, washing, and drying in an oven to obtain a prefabricated flame retardant;

[0012] Step S2: placing the prefabricated flame retardant and anhydrous ethanol in a reaction kettle and stirring to mix, adding an initiator and stirring to preheat, adding DOPO and heating and stirring, centrifuging, washing, and drying in an oven to obtain an organic / inorganic hybrid flame retardant.

[0013] Furthermore, the gas phase flame retardant mechanism of the P element is mainly through the generation of volatile free radicals, capturing free radicals generated by combustion, delaying the combustion chain reaction, and generating flame-retardant gases through high-temperature decomposition, diluting the concentration of combustible gases, and delaying the spread of flames; at the same time, the compounds of the P element will also form a liquid phosphoric acid film during combustion to protect the polymer matrix, and further dehydrate to form metaphosphoric acid, which is further polymerized to form polymetaphosphoric acid. These compounds form a phosphorus-containing carbonized protective layer in the condensed phase, which can reduce oxygen diffusion and heat and mass transfer between the gas phase and the solid phase, inhibit the carbon oxidation process, and reduce the concentration of combustible substances and combustible gases.

[0014] As a preferred technical solution of the present invention, in step S1, the ultrasonic mixing is performed at a frequency of 200-230W for 12-15min; the heating stirring is performed at a heating rate of 5°C / min to a temperature of 60-70°C and stirring for 3-4h.

[0015] As a preferred technical solution of the present invention, in step S1, the washing is performed by washing with anhydrous ethanol for 3 times; and the drying in the oven is performed by drying at a temperature of 80° C. to a constant weight.

[0016] As a preferred technical solution of the present invention, in step S1, the mass ratio of the expandable graphite, anhydrous ethanol, 3,4-dihydroxyaniline and mixed monomer is 20-23:60-70:4.0-4.6:5-6.

[0017] As a preferred technical solution of the present invention, in step S1, the mixed monomers are vinyl salicylaldehyde and 3-(trifluoromethyl) salicylaldehyde in a mass ratio of 3:1.0-1.3.

[0018] As a preferred technical solution of the present invention, in step S2, the stirring and mixing is stirring at a rotation speed of 500-600 r / min for 45-60 min.

[0019] As a preferred technical solution of the present invention, in step S2, the preheating is to heat to 40-50°C; the heating and stirring is to stir at 68-75°C for 12-15h; the washing is to wash 3 times with anhydrous ethanol; and the drying in the oven is to dry at 80°C to constant weight.

[0020] As a preferred technical solution of the present invention, in step S2, the mass ratio of the prefabricated flame retardant, anhydrous ethanol, initiator and DOPO is 10-11:30-36:0.13-0.16:3.0-3.6.

[0021] As a preferred technical solution of the present invention, in step S2, the initiator is azobisisobutyronitrile; DOPO in the embodiments and comparative examples of the present invention is the flame retardant 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide.

[0022] The invention discloses a method for preparing the wear-resistant flame-retardant layer, comprising the following steps: weighing high-density polyethylene, a compatibilizer and an organic / inorganic hybrid flame retardant by weight, mixing them, kneading them at 160-170°C for 20-26 minutes, placing them in a twin-screw extruder, and melt-extruding them at 180-210°C to obtain the wear-resistant flame-retardant layer.

[0023] The invention discloses a method for preparing a HDPE flame-retardant pipe for power communication, the preparation method comprising the following steps:

[0024] S1. Surrounding the bundled multiple power communication cables to form a shielding layer, and filling an elastic elastic material between the shielding layer and the power communication cables;

[0025] S2, wrapping the melted anti-oxidation layer material on the outer wall of the shielding layer to form an anti-oxidation layer;

[0026] S3, wrapping the melted wear-resistant and flame-retardant layer material on the outer wall of the anti-oxidation layer to form a wear-resistant and flame-retardant layer.

[0027] Beneficial effects of the present invention:

[0028] 1. The HDPE flame-retardant pipe of the present invention comprises a plurality of power communication cables, a shielding layer and an anti-oxidation layer, wherein the shielding layer wraps the plurality of power communication cables, the anti-oxidation layer is adhered to the outer surface of the shielding layer, and a wear-resistant flame-retardant layer is provided on the outer surface of the anti-oxidation layer. The wear-resistant flame-retardant layer is made of high-density polyethylene, a compatibilizer and an organic / inorganic hybrid flame retardant as raw materials, and can effectively protect the HDPE flame-retardant pipe, and has anti-oxidation and corrosion resistance as well as excellent mechanical strength.

[0029] 2. The present invention can significantly improve the flame retardant properties of the material while maintaining other physical properties of the material by introducing the combined effects of the different flame retardant mechanisms of fluorine, phosphorus, nitrogen-containing Schiff base structure and thermally stable expandable graphite. Specifically, the organic / inorganic hybrid flame retardant enables the polyethylene composite material to form a stable carbon layer during the combustion process, blocking oxygen and heat, while absorbing a large amount of heat and reducing the surface temperature of the material, thereby effectively preventing the spread of fire and achieving a flame retardant effect. DETAILED DESCRIPTION

[0030] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation methods, structures, features and effects of the present invention are described in detail below in combination with the embodiments.

[0031] A HDPE flame-retardant pipe for power communication comprises a plurality of power communication cables, a shielding layer and an anti-oxidation layer, wherein the shielding layer wraps the plurality of power communication cables, the anti-oxidation layer is adhered to the outer surface of the shielding layer, and a wear-resistant flame-retardant layer is provided on the outer surface of the anti-oxidation layer, wherein the wear-resistant flame-retardant layer is made of high-density polyethylene, a compatibilizer and an organic / inorganic hybrid flame retardant as raw materials.

[0032] Furthermore, an elastic object is provided between the power communication cable and the shielding layer; the material of the elastic object is elastic resin.

[0033] Furthermore, the shielding layer includes a stainless steel tube, an aramid fiber sheath and a metal woven mesh layer; the aramid fiber sheath covers the stainless steel tube; the metal woven mesh layer is arranged on the outer wall of the aramid fiber sheath, and the material of the metal woven mesh layer is one or more of copper alloy, aluminum alloy and magnesium alloy.

[0034] A method for preparing a HDPE flame-retardant pipe for power communication comprises the following steps:

[0035] S1. Surrounding the bundled multiple power communication cables to form a shielding layer, and filling an elastic elastic material between the shielding layer and the power communication cables;

[0036] S2, wrapping the melted anti-oxidation layer material on the outer wall of the shielding layer to form an anti-oxidation layer;

[0037] S3, wrapping the melted wear-resistant and flame-retardant layer material on the outer wall of the anti-oxidation layer to form a wear-resistant and flame-retardant layer.

[0038] Example 1

[0039] The wear-resistant flame-retardant layer comprises the following components by weight: 80 parts of high-density polyethylene, 5 parts of a compatibilizer and 15 parts of an organic / inorganic hybrid flame retardant; the compatibilizer is a styrene-butadiene-glyceryl methacrylate copolymer.

[0040] The preparation method of the organic / inorganic hybrid flame retardant comprises the following steps:

[0041] Step S1: placing expandable graphite, anhydrous ethanol and 3,4-dihydroxyaniline in a reaction kettle for ultrasonic mixing, adding a mixed monomer, heating and stirring, centrifuging, washing, and drying in an oven to obtain a prefabricated flame retardant; wherein the ultrasonic mixing is ultrasonic mixing at a frequency of 200W for 12 minutes; the heating and stirring is heating to 60°C at a heating rate of 5°C / min and stirring for 3 hours; the washing is washing with anhydrous ethanol for 3 times; the drying in the oven is drying at 80°C to constant weight; the mass ratio of the expandable graphite, anhydrous ethanol, 3,4-dihydroxyaniline and the mixed monomer is 20:60:4.0:5; the mixed monomer is vinyl salicylaldehyde and 3-(trifluoromethyl) salicylaldehyde in a mass ratio of 3:1.0;

[0042] Step S2: After the prefabricated flame retardant and anhydrous ethanol are placed in a reactor and stirred and mixed, an initiator is added and stirred and heated and preheated, DOPO is added and heated and stirred, centrifuged, washed, and placed in an oven for drying to obtain an organic / inorganic hybrid flame retardant; wherein the stirring and mixing is stirring at a speed of 500 r / min for 45 minutes; the heating and preheating is heating to 40°C; the heating and stirring is stirring at 68°C for 12 hours; the washing is washing with anhydrous ethanol for 3 times; the drying in the oven is drying at 80°C to constant weight; the mass ratio of the prefabricated flame retardant, anhydrous ethanol, initiator and DOPO is 10:30:0.13:3.0; and the initiator is azobisisobutyronitrile.

[0043] The preparation method of the wear-resistant flame-retardant layer comprises the following steps: weighing high-density polyethylene, a compatibilizer and an organic / inorganic hybrid flame retardant by weight, mixing them, kneading them at 160° C. for 20 minutes, placing them in a twin-screw extruder, and melt-extruding them at 180° C. to obtain a wear-resistant flame-retardant layer.

[0044] Example 2

[0045] The wear-resistant flame-retardant layer comprises the following components by weight: 83 parts of high-density polyethylene, 5.7 parts of a compatibilizer and 17 parts of an organic / inorganic hybrid flame retardant; the compatibilizer is a styrene-butadiene-glyceryl methacrylate copolymer.

[0046] The preparation method of the organic / inorganic hybrid flame retardant comprises the following steps:

[0047] Step S1: placing expandable graphite, anhydrous ethanol and 3,4-dihydroxyaniline in a reaction kettle for ultrasonic mixing, adding a mixed monomer, heating and stirring, centrifuging, washing, and drying in an oven to obtain a prefabricated flame retardant; wherein the ultrasonic mixing is ultrasonic mixing at a frequency of 210W for 13 minutes; the heating and stirring is heating to 63°C at a heating rate of 5°C / min and stirring for 3.3 hours; the washing is washing with anhydrous ethanol for 3 times; the drying in the oven is drying at 80°C to constant weight; the mass ratio of the expandable graphite, anhydrous ethanol, 3,4-dihydroxyaniline and the mixed monomer is 21:63:4.2:5.3; the mixed monomer is vinyl salicylaldehyde and 3-(trifluoromethyl) salicylaldehyde in a mass ratio of 3:1.1;

[0048] Step S2: After the prefabricated flame retardant and anhydrous ethanol are placed in a reactor and stirred and mixed, an initiator is added, stirred and heated for preheating, DOPO is added, heated and stirred, centrifuged, washed, and placed in an oven for drying to obtain an organic / inorganic hybrid flame retardant; wherein, the stirring and mixing is stirring at a speed of 530r / min for 50min; the heating and preheating is heating to 43°C; the heating and stirring is stirring at 70°C for 13h; the washing is washing with anhydrous ethanol for 3 times; the drying in the oven is drying at 80°C to constant weight; the mass ratio of the prefabricated flame retardant, anhydrous ethanol, initiator and DOPO is 10.3:32:0.14:3.2; and the initiator is azobisisobutyronitrile.

[0049] The preparation method of the wear-resistant flame-retardant layer comprises the following steps: weighing high-density polyethylene, a compatibilizer and an organic / inorganic hybrid flame retardant by weight, mixing them, kneading them at 165° C. for 22 minutes, placing them in a twin-screw extruder, and melt-extruding them at 190° C. to obtain a wear-resistant flame-retardant layer.

[0050] Example 3

[0051] The wear-resistant flame-retardant layer comprises the following components by weight: 87 parts of high-density polyethylene, 6.3 parts of a compatibilizer and 18 parts of an organic / inorganic hybrid flame retardant; the compatibilizer is a styrene-butadiene-glyceryl methacrylate copolymer.

[0052] The preparation method of the organic / inorganic hybrid flame retardant comprises the following steps:

[0053] Step S1: placing expandable graphite, anhydrous ethanol and 3,4-dihydroxyaniline in a reaction kettle for ultrasonic mixing, adding a mixed monomer, heating and stirring, centrifuging, washing, and drying in an oven to obtain a prefabricated flame retardant; wherein the ultrasonic mixing is ultrasonic mixing at a frequency of 220W for 14 minutes; the heating and stirring is heating to 67°C at a heating rate of 5°C / min and stirring for 3.7 hours; the washing is washing with anhydrous ethanol for 3 times; the drying in the oven is drying at 80°C to constant weight; the mass ratio of the expandable graphite, anhydrous ethanol, 3,4-dihydroxyaniline and the mixed monomer is 22:67:4.4:5.7; the mixed monomer is vinyl salicylaldehyde and 3-(trifluoromethyl) salicylaldehyde in a mass ratio of 3:1.2;

[0054] Step S2: After the prefabricated flame retardant and anhydrous ethanol are placed in a reactor and stirred and mixed, an initiator is added and stirred and heated and preheated, DOPO is added and heated and stirred, centrifuged, washed, and placed in an oven for drying to obtain an organic / inorganic hybrid flame retardant; wherein, the stirring and mixing is stirring at a speed of 560r / min for 55min; the heating and preheating is heating to 46°C; the heating and stirring is stirring at 75°C for 14h; the washing is washing with anhydrous ethanol for 3 times; the drying in the oven is drying at 80°C to constant weight; the mass ratio of the prefabricated flame retardant, anhydrous ethanol, initiator and DOPO is 10.7:34:0.15:3.4; and the initiator is azobisisobutyronitrile.

[0055] The preparation method of the wear-resistant flame-retardant layer comprises the following steps: weighing high-density polyethylene, a compatibilizer and an organic / inorganic hybrid flame retardant by weight, mixing them, kneading them at 168° C. for 25 minutes, placing them in a twin-screw extruder, and melt-extruding them at 200° C. to obtain a wear-resistant flame-retardant layer.

[0056] Example 4

[0057] The wear-resistant flame-retardant layer comprises the following components by weight: 90 parts of high-density polyethylene, 7 parts of a compatibilizer and 20 parts of an organic / inorganic hybrid flame retardant; the compatibilizer is a styrene-butadiene-glyceryl methacrylate copolymer.

[0058] The preparation method of the organic / inorganic hybrid flame retardant comprises the following steps:

[0059] Step S1: placing expandable graphite, anhydrous ethanol and 3,4-dihydroxyaniline in a reaction kettle for ultrasonic mixing, adding a mixed monomer, heating and stirring, centrifuging, washing, and drying in an oven to obtain a prefabricated flame retardant; wherein the ultrasonic mixing is ultrasonic mixing at a frequency of 230W for 15 minutes; the heating and stirring is heating to 70°C at a heating rate of 5°C / min and stirring for 4 hours; the washing is washing with anhydrous ethanol for 3 times; the drying in the oven is drying at 80°C to constant weight; the mass ratio of the expandable graphite, anhydrous ethanol, 3,4-dihydroxyaniline and the mixed monomer is 23:70:4.6:6; the mixed monomer is vinyl salicylaldehyde and 3-(trifluoromethyl) salicylaldehyde in a mass ratio of 3:1.3;

[0060] Step S2: After the prefabricated flame retardant and anhydrous ethanol are placed in a reactor and stirred and mixed, an initiator is added and stirred and heated and preheated, DOPO is added and heated and stirred, centrifuged, washed, and placed in an oven for drying to obtain an organic / inorganic hybrid flame retardant; wherein the stirring and mixing is stirring at a speed of 600 r / min for 60 minutes; the heating and preheating is heating to 50°C; the heating and stirring is stirring at 75°C for 15 hours; the washing is washing with anhydrous ethanol for 3 times; the drying in the oven is drying at 80°C to constant weight; the mass ratio of the prefabricated flame retardant, anhydrous ethanol, initiator and DOPO is 11:36:0.16:3.6; and the initiator is azobisisobutyronitrile.

[0061] The preparation method of the wear-resistant flame-retardant layer comprises the following steps: weighing high-density polyethylene, a compatibilizer and an organic / inorganic hybrid flame retardant by weight, mixing them, kneading them at 170° C. for 26 minutes, placing them in a twin-screw extruder, and melt-extruded at 210° C. to obtain a wear-resistant flame-retardant layer.

[0062] Comparative Example 1

[0063] Compared with Example 3, the difference in Comparative Example 1 is that the mixed monomer in Comparative Example 1 is vinyl salicylaldehyde, and the other components, preparation steps and parameters are the same.

[0064] Comparative Example 2

[0065] Compared with Example 3, the difference of Comparative Example 2 is that the mixed monomer of Comparative Example 2 is 3-(trifluoromethyl) salicylaldehyde, and the other components, preparation steps and parameters are the same.

[0066] Comparative Example 3

[0067] Compared with Example 3, the difference of Comparative Example 3 is that Comparative Example 3 uses 3-fluorosalicylaldehyde instead of 3-(trifluoromethyl)salicylaldehyde, and the other components, preparation steps and parameters are the same.

[0068] Comparative Example 4

[0069] Compared with Example 3, Comparative Example 4 is different in that styrene is used in place of vinyl salicylaldehyde in Comparative Example 4, and the other components, preparation steps and parameters are the same.

[0070] Comparative Example 5

[0071] Compared with Example 3, Comparative Example 5 is different in that no mixed monomer is used in Comparative Example 5, and the other components, preparation steps and parameters are the same.

[0072] Comparative Example 6

[0073] Compared with Example 3, Comparative Example 6 is different in that no reactive monomer is used in Comparative Example 6, and the other components, preparation steps and parameters are the same.

[0074] Comparative Example 7

[0075] Compared with Example 3, the difference in Comparative Example 7 is that DOPO is not used in Comparative Example 7, and the other components, preparation steps and parameters are the same.

[0076] Comparative Example 8

[0077] Compared with Example 3, the difference in Comparative Example 8 is that Comparative Example 8 does not use 3,4-dihydroxyaniline, and the other components, preparation steps and parameters are the same.

[0078] Comparative Example 9

[0079] Compared with Example 3, the difference of Comparative Example 9 is that Comparative Example 9 does not use expandable graphite, and the other components, preparation steps and parameters are the same.

[0080] The HDPE flame retardant pipes prepared in Examples 1-4 were subjected to the following mechanical property tests, and the test results are shown in Table 1.

[0081] Mechanical properties test: According to GB / T 2951.11-2008.

[0082] Table 1

[0083]

[0084] It can be seen from the test results in Table 1 that the HDPE flame-retardant pipes prepared in Examples 1-4 of the present invention have good mechanical properties and are not easy to wear.

[0085] The HDPE flame retardant pipes prepared in Examples 1-4 and Comparative Examples 1-9 were subjected to the following limiting oxygen index test, and the test results are shown in Table 2.

[0086] Table 2

[0087] Limiting oxygen index (%) Example 1 31.5 Example 2 31.7 Example 3 32.1 Example 4 31.8 Comparative Example 1 24.5 Comparative Example 2 25.2 Comparative Example 3 27.7 Comparative Example 4 25.3 Comparative Example 5 28.1 Comparative Example 6 20.6 Comparative Example 7 26.3 Comparative Example 8 24.9 Comparative Example 9 24.4

[0088] Compared with comparative examples 1-9, the HDPE flame retardant pipe prepared in the present invention has thermal stability and a higher limiting oxygen index. Analysis and comparison show that the present invention introduces 3,4-dihydroxyaniline on expandable graphite, which can be loaded on expandable graphite through hydrogen bonding, and its amino group can form a Schiff base structure with the aldehyde group in the mixed monomer, introduces fluorine element and vinyl group, and then grafts DOPO through the vinyl group, introduces P element, so as to form an inorganic inside and organic outside package structure, which is used in the high-density polyethylene system. During the combustion process of the wear-resistant flame retardant layer material, the polyfluorine element in the organic / inorganic hybrid flame retardant burns to generate non-combustible gas to dilute the gas phase. The concentration of oxygen and combustible gas in the mixture, combined with the P element, can play a gas-phase flame retardant role. At the same time, expandable graphite has excellent thermal stability. It can quickly form a dense carbon layer during combustion. Combined with the Schiff base structure, it can cross-link with each other under high temperature conditions to form a polybenzoxazine with a stable structure. Combined with the migration of the P element to the surface, the three different carbonization mechanisms can better strengthen the carbon layer and form a dense carbon layer structure, thereby enhancing the barrier and protection of the residue and making it have higher flame retardant properties.

[0089] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A HDPE flame retardant tube for power communication, characterized by: The HDPE flame retardant tube comprises a plurality of power communication cables, a shielding layer and an anti-oxidation layer, wherein the shielding layer wraps the plurality of power communication cables, the anti-oxidation layer is attached to the outer surface of the shielding layer, and a wear-resistant flame retardant layer is provided on the outer surface of the anti-oxidation layer, wherein the wear-resistant flame retardant layer is made of high-density polyethylene, a compatibilizer and an organic / inorganic hybrid flame retardant as raw materials; The preparation method of the organic / inorganic hybrid flame retardant comprises the following steps: Step S1: placing expandable graphite, anhydrous ethanol and 3,4-dihydroxyaniline in a reaction kettle for ultrasonic mixing, adding a mixed monomer, heating and stirring, centrifuging, washing, and placing in an oven for drying to obtain a prefabricated flame retardant; the mass ratio of the expandable graphite, anhydrous ethanol, 3,4-dihydroxyaniline and the mixed monomer is 20-23:60-70:4.0-4.6:5-6; the mixed monomer is vinyl salicylaldehyde and 3-(trifluoromethyl) salicylaldehyde in a mass ratio of 3:1.0-1.3; Step S2: placing the prefabricated flame retardant and anhydrous ethanol in a reaction kettle and stirring and mixing, adding an initiator and stirring and heating to preheat, adding DOPO and heating and stirring, centrifuging, washing, and placing in an oven to dry to obtain an organic / inorganic hybrid flame retardant; the mass ratio of the prefabricated flame retardant, anhydrous ethanol, initiator and DOPO is 10-11:30-36:0.13-0.16:3.0-3.6; the initiator is azobisisobutyronitrile; and the DOPO is 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide.

2. The HDPE flame-retardant tube for power communication according to claim 1, characterized in that: An elastic object is provided between the power communication cable and the shielding layer; the material of the elastic object is elastic resin.

3. The HDPE flame-retardant tube for power communication according to claim 1, characterized in that: The shielding layer includes a stainless steel tube, an aramid fiber sheath and a metal braided mesh layer; the aramid fiber sheath covers the stainless steel tube; the metal braided mesh layer is arranged on the outer wall of the aramid fiber sheath, and the material of the metal braided mesh layer is one or more of copper alloy, aluminum alloy and magnesium alloy.

4. The HDPE flame-retardant tube for power communication according to claim 1, characterized in that: The wear-resistant flame-retardant layer comprises the following components by weight: 80-90 parts of high-density polyethylene, 5-7 parts of a compatibilizer and 15-20 parts of an organic / inorganic hybrid flame retardant; the compatibilizer is a styrene-butadiene-glyceryl methacrylate copolymer.

5. The HDPE flame-retardant tube for power communication according to claim 1, characterized in that: In step S1, the ultrasonic mixing is performed at a frequency of 200-230 W for 12-15 min; the heating stirring is performed at a heating rate of 5°C / min to a temperature of 60-70°C and stirring for 3-4 h; the washing is performed 3 times with anhydrous ethanol; and the drying in the oven is performed at a temperature of 80°C to constant weight.

6. The HDPE flame-retardant tube for power communication according to claim 1, characterized in that: In step S2, the stirring and mixing is stirring at a speed of 500-600 r / min for 45-60 minutes; the preheating is heating to a temperature of 40-50°C; the heating and stirring is stirring at a temperature of 68-75°C for 12-15 hours; the washing is washing 3 times with anhydrous ethanol; and the drying in the oven is drying at a temperature of 80°C to constant weight.

7. The HDPE flame-retardant tube for power communication according to claim 1, characterized in that: The preparation method of the wear-resistant flame-retardant layer comprises the following steps: weighing high-density polyethylene, a compatibilizer and an organic / inorganic hybrid flame retardant by weight, mixing them, kneading them at 160-170° C. for 20-26 minutes, placing them in a twin-screw extruder, and melt-extruding them at 180-210° C. to obtain a wear-resistant flame-retardant layer.

8. A method for preparing a HDPE flame-retardant tube for power communication according to any one of claims 1 to 7, characterized in that: The preparation method comprises the following steps: S1. Surrounding the bundled multiple power communication cables to form a shielding layer, and filling an elastic elastic material between the shielding layer and the power communication cables; S2, wrapping the melted anti-oxidation layer material on the outer wall of the shielding layer to form an anti-oxidation layer; S3, wrapping the melted wear-resistant and flame-retardant layer material on the outer wall of the anti-oxidation layer to form a wear-resistant and flame-retardant layer.

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