Flame-retardant insulating composite material as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of new materials, and particularly relates to a flame-retardant insulating composite material which is prepared from the following raw materials: 5-25 parts of polyethylene, 60-80 parts of an ethylene-vinyl acetate copolymer, 3-15 parts of an ethylene-octylene copolymer, 1-5 parts of vinyl silane, 1-3 parts of dimethyl silicone oil, 10-40 parts of an in-situ composite flame retardant and 0.1-1 part of an antioxidant. The in-situ composite flame retardant has good flame retardance and insulativity and can be used for preparing soft plastic flame-retardant insulating products (such as insulating blankets, insulating gloves and insulating clothes), and the prepared soft plastic flame-retardant insulating products have comfortable softness, good use touch feeling and foldability and excellent flame retardance and insulativity.

Description

Technical Field

[0001] The present invention belongs to the technical field of new materials, and in particular relates to a flame retardant insulating composite material and a preparation method and application thereof. Background Art

[0002] Flame-retardant composite materials and insulating composite materials are very common in our daily life. Common flame-retardant materials include aluminum hydroxide, magnesium hydroxide, borates, phosphates, halides, molybdates, natural inorganic minerals, etc. There are even more common insulating materials. As we all know, except for metal materials and some semiconductor materials, most conventional glass, ceramics, cement, etc. are insulating, and a large part of organic polymers are also insulating, such as common polyethylene, polypropylene, polyvinyl chloride, nylon and a large part of polyester polyether and other polymers. For example, patent application number CN202310069836.6 discloses a cross-linked polyethylene flame-retardant insulating material composed primarily of the following raw materials in parts by weight: 100 parts low-density polyethylene resin, 40-50 parts allyl succinic anhydride-modified ethylene-vinyl acetate copolymer, 10-20 parts ethylene-acrylate-glycidyl methacrylate terpolymer, 4-6 parts peroxide crosslinker, 18-22 parts calcium sulfate whiskers, 18-22 parts ammonium polyphosphate, 9-11 parts aluminum hydroxide, 1-3 parts antioxidant, and 2-4 parts lubricant. Patent application number CN202210950583.9 discloses a flame-retardant insulating material composed of a phosphazene flame retardant, a phosphorus-containing silicon organic flame retardant, and modified mica in a mass ratio of 1-10:1-6:1-5. Patent application number CN202010273561.4 discloses an insulated flame-retardant polyvinyl chloride electrical conduit. The insulating flame-retardant material components of this conduit include, by weight, 40-60 parts polyvinyl chloride, 20-40 parts polyolefin, 5-15 parts wear-resistant carbon black, 8-20 parts zirconium tetrafluoride, 7-14 parts ferrite nanoparticles, 3-9 parts calcined clay, 10-20 parts nanosilica, 7-15 parts azobisisobutyronitrile, 6-10 parts active silicon powder, 2-4 parts reinforcing fiber, and 3-9 parts toughening modifier. As can be seen from the above patent documents, existing research on flame-retardant insulating composite materials has mostly focused on flame-retardant insulated cables and electrical insulating conduits. For new demands for applications in insulating blankets, insulating gloves, insulating clothing, etc., while meeting the insulation requirements, it is also necessary to meet the flame retardant properties and comfort of use. However, there is little research in the existing technology on soft plastic flame retardant insulating materials used in insulating blankets, insulating gloves, insulating clothing, etc.; therefore, there is an urgent need to study a new flame retardant insulating composite material that can be used to prepare soft plastic flame retardant insulating materials to expand the application in the field of flame retardant insulation. Summary of the Invention

[0003] In view of the problems and shortcomings in the prior art, the present invention aims to provide a flame retardant insulating composite material and a preparation method and application thereof.

[0004] To achieve the purpose of the invention, the technical solution adopted by the present invention is as follows:

[0005] A first aspect of the present invention provides a method for preparing a magnesium-aluminum composite, comprising the following steps:

[0006] (1) adding magnesium chloride to a polyethylene glycol solution, stirring and dissolving, to obtain a mixed solution; dropping a sodium borate solution into the mixed solution, stirring and reacting; then adding a sodium hydroxide solution to the reaction system, stirring and reacting;

[0007] (2) adding aluminum chloride solution dropwise to the reaction system obtained in step (1) and stirring for reaction; then adding sodium hydroxide solution to the reaction system and stirring for reaction;

[0008] (3) adding an aluminum chloride-magnesium chloride mixture dropwise to the reaction system obtained in step (2), stirring for reaction, allowing the mixture to stand after the reaction is completed, filtering to collect the precipitate, and washing and drying the precipitate to obtain a boron-magnesium-aluminum complex.

[0009] According to the above-mentioned method for preparing the boron-magnesium-aluminum composite, preferably, in step (1), the mass ratio of polyethylene glycol to magnesium chloride is 1:(1-2); by controlling the mass ratio of polyethylene glycol to magnesium chloride to be 1:(1-2), the reaction can be fully carried out without affecting the reaction process. If the mass ratio of polyethylene glycol to magnesium chloride is greater than 1:(1-2), there is too much polyethylene glycol in the reaction system, which not only causes waste but also affects the reaction process. If the mass ratio of polyethylene glycol to magnesium chloride is less than 1:(1-2), there is too little polyethylene glycol, and the dispersion effect on the reaction is insufficient. More preferably, the mass ratio of polyethylene glycol to magnesium chloride is 1:1.5.

[0010] According to the above-mentioned method for preparing the boron-magnesium-aluminum composite, preferably, in step (1), the mass ratio of the magnesium chloride to the sodium borate is 1:(2-3); more preferably, the mass ratio of the magnesium chloride to the sodium borate is 1:2.12.

[0011] According to the above-mentioned method for preparing the boron-magnesium-aluminum composite, preferably, in step (1), the mass ratio of sodium borate to sodium hydroxide is 1:(1.5-3); more preferably, the mass ratio of sodium borate to sodium hydroxide is 1:1.99.

[0012] According to the above-mentioned method for preparing the boron-magnesium-aluminum composite, preferably, in step (2), the mass ratio of the aluminum chloride to the sodium borate is (1-2):1; more preferably, the mass ratio of the aluminum chloride to the sodium borate is 1.42:1.

[0013] According to the above-mentioned method for preparing the boron-magnesium-aluminum composite, preferably, in step (2), the mass ratio of sodium hydroxide to sodium borate is (1-2):1; more preferably, the mass ratio of sodium hydroxide to sodium borate is 1.57:1.

[0014] According to the above-mentioned method for preparing the boron-magnesium-aluminum composite, preferably, in step (3), the mass ratio of the total mass of aluminum chloride and magnesium chloride in the aluminum chloride-magnesium chloride mixture to sodium borate is (1.2-2.5):1; more preferably, the mass ratio of the total mass of aluminum chloride and magnesium chloride in the aluminum chloride-magnesium chloride mixture to sodium borate is 1.81:1.

[0015] According to the above-mentioned method for preparing the boron-magnesium-aluminum composite, preferably, in step (3), the mass ratio of aluminum chloride to magnesium chloride in the aluminum chloride-magnesium chloride mixture is 1:(1-2); more preferably, the mass ratio of aluminum chloride to magnesium chloride in the aluminum chloride-magnesium chloride mixture is 1:1.32.

[0016] According to the above-mentioned method for preparing the boron-magnesium-aluminum composite, preferably, in step (1), the stirring reaction time is 5-45 minutes after the sodium borate solution is added dropwise, and the stirring reaction time is 5-45 minutes after sodium hydroxide is added to the reaction system, and the stirring speed is 200 rpm; more preferably, the stirring reaction time is 20 minutes after the sodium borate solution is added dropwise, and the stirring reaction time is 20 minutes after sodium hydroxide is added to the reaction system.

[0017] According to the above-mentioned method for preparing the boron-magnesium-aluminum composite, preferably, in step (2), the stirring reaction time after the aluminum chloride solution is added dropwise is 10-40 minutes, the stirring reaction time after sodium hydroxide is added to the reaction system is 10-40 minutes, and the stirring speed is 300 rpm; more preferably, the stirring reaction time after the aluminum chloride solution is added dropwise is 20 minutes, and the stirring reaction time after sodium hydroxide is added to the reaction system is 20 minutes.

[0018] According to the above-mentioned method for preparing the boron-magnesium-aluminum composite, preferably, in step (3), the stirring reaction time after the aluminum chloride-magnesium chloride mixture is added dropwise is 20-60 minutes, the standing treatment time is 4-12 hours, and the stirring speed is 500 rpm; more preferably, the stirring reaction time after the aluminum chloride-magnesium chloride mixture is added dropwise is 30 minutes, and the standing treatment time is 6 hours.

[0019] According to the above-mentioned method for preparing the boron-magnesium-aluminum composite, preferably, in step (1), the polyethylene glycol is polyethylene glycol 2000; the mass fraction of the polyethylene glycol solution is 8%; the mass fraction of the sodium borate solution is 10%; and the mass fraction of the sodium hydroxide solution is 10%.

[0020] According to the above-mentioned method for preparing the boron-magnesium-aluminum composite, preferably, in step (2), the mass fraction of the aluminum chloride solution is 30%, and the mass fraction of the sodium hydroxide solution is 10%.

[0021] The second aspect of this patent provides a boron-magnesium-aluminum composite prepared using the boron-magnesium-aluminum composite preparation method described in the first aspect above.

[0022] The third aspect of this patent provides a method for preparing an in-situ composite flame retardant, which comprises the following steps:

[0023] S1, adding the boron magnesium aluminum complex and vinyl tris (2-methoxyethoxy) silane described in the second aspect to solvent A, mixing them evenly to obtain a prepolymer mixture;

[0024] S2. Add vinyl acetate to solvent B and stir to dissolve. Then add the prepolymer mixture prepared in step S1 and stir to mix. Then add tert-butyl peroxy 2-ethylhexanoate and stir to react at 40-55° C. for 15-60 min. Then stir to react at 60-65° C. for 4-8 h. After the reaction is completed, filter and collect the precipitate. Wash and dry the precipitate to obtain an in-situ composite flame retardant.

[0025] According to the above-mentioned method for preparing the in-situ composite flame retardant, preferably, in step S1, the mass ratio of the vinyl tris (2-methoxyethoxy) silane to the boron magnesium aluminum complex is 1: (0.2-1); more preferably, the mass ratio of the vinyl tris (2-methoxyethoxy) silane to the boron magnesium aluminum complex is 1: 1.

[0026] According to the above-mentioned method for preparing the in-situ composite flame retardant, preferably, in step S1, the mass ratio of the vinyltris(2-methoxyethoxy)silane to the solvent A is 1:(5-10); more preferably, the mass ratio of the vinyltris(2-methoxyethoxy)silane to the solvent A is 1:8.

[0027] According to the above-mentioned method for preparing the in-situ composite flame retardant, preferably, in step S2, the mass ratio of vinyl acetate to vinyltris(2-methoxyethoxy)silane is (0.5-2):1; more preferably, the mass ratio of vinyl acetate to vinyltris(2-methoxyethoxy)silane is 1:1.

[0028] According to the above-mentioned method for preparing the in-situ composite flame retardant, preferably, in step S2, the mass ratio of the solvent B to vinyl acetate is 1:(1-10); more preferably, the mass ratio of the solvent B to vinyl acetate is 1:5.

[0029] According to the above-mentioned preparation method of the in-situ composite flame retardant, preferably, in step S2, the mass ratio of the tert-butyl peroxide 2-ethylhexanoate to vinyl acetate is (0.001-0.01):1; more preferably, the mass ratio of the tert-butyl peroxide 2-ethylhexanoate to vinyl acetate is 0.003:1.

[0030] According to the above-mentioned preparation method of the in-situ composite flame retardant, preferably, the solvent A is at least one of anhydrous ethanol, methanol, isopropanol, dimethyl carbonate, and acetone; the solvent B is at least one of anhydrous ethanol, methanol, isopropanol, dimethyl carbonate, and acetone.

[0031] According to the above-mentioned preparation method of the in-situ composite flame retardant, preferably, in step S2, the stirring reaction process after adding tert-butyl peroxy 2-ethylhexanoate is: first stirring and reacting at 50°C for 30 minutes, then stirring and reacting at 65°C for 4 hours, and finally stirring and reacting at 60°C for 2 hours.

[0032] The fourth aspect of this patent provides an in-situ composite flame retardant prepared using the preparation method described in the third aspect above.

[0033] The fifth aspect of this patent provides the use of the boron magnesium aluminum composite described in the second aspect or the in-situ composite flame retardant described in the fourth aspect in flame retardants, flame retardant materials and / or flame retardant insulating materials.

[0034] The sixth aspect of this patent provides a flame-retardant insulating composite material, which contains the in-situ composite flame retardant described in the fourth aspect.

[0035] According to the above-mentioned flame retardant insulating composite material, preferably, the flame retardant insulating composite material is made of the following raw materials, by weight: 25 parts of polyethylene, 60-80 parts of ethylene-vinyl acetate copolymer (EVA), 3-15 parts of ethylene-octene copolymer (POE), 1-5 parts of vinyl silane, 1-3 parts of dimethyl silicone oil, 10-40 parts of in-situ composite flame retardant, and 0.1-1 part of antioxidant.

[0036] According to the above-mentioned flame-retardant insulating composite material, preferably, the content of vinyl acetate in the ethylene-vinyl acetate copolymer is 20%-35%; more preferably, the content of vinyl acetate in the ethylene-vinyl acetate copolymer is 28%; further preferably, the ethylene-vinyl acetate copolymer is Formosa Plastics-EVA-7350M and / or Yanshan Petrochemical-EVA-18J3.

[0037] According to the flame-retardant insulating composite material, preferably, the polyethylene is at least one of high-density polyethylene (HDPE), low-density polyethylene (LDPE) and linear low-density polyethylene (LLDPE).

[0038] Most preferably, according to the flame retardant insulation composite material, preferably, the ethylene-octene copolymer is POE8480 from Dow Chemical of the United States.

[0039] According to the flame-retardant insulating composite material, preferably, the vinyl silane is at least one of trivinylsilane and divinylsilane.

[0040] According to the above-mentioned flame-retardant insulating composite material, preferably, the antioxidant is at least one of antioxidant 1010, antioxidant 168, and antioxidant 1076; more preferably, the antioxidant is a mixture of antioxidant 1010 and antioxidant 168, and the mass ratio of antioxidant 1010 to antioxidant 168 in the antioxidant is 2:1.

[0041] The seventh aspect of this patent provides the application of the flame-retardant insulating composite material described in the sixth aspect in insulating products.

[0042] According to the above application, preferably, the insulating product is a soft plastic flame retardant insulating product; more preferably, the soft plastic flame retardant insulating product includes an insulating blanket, insulating gloves, and insulating clothing.

[0043] The eighth aspect of this patent provides a method for preparing the flame-retardant insulating composite material described in the sixth aspect above, and the preparation method of the flame-retardant insulating composite material comprises: mixing polyethylene, ethylene-vinyl acetate copolymer, and ethylene-octene copolymer evenly to obtain a mixture; adding vinyl silane and dimethyl silicone oil to the mixture, mixing evenly, and then adding an in-situ composite flame retardant and an antioxidant, mixing evenly, and then melt-blending, extruding, and granulating to obtain the insulating composite material.

[0044] In the method for preparing a flame-retardant insulating composite material, preferably, the melt blending temperature is 135-160°C. More preferably, the melt blending is performed in a twin-screw extruder, and the temperatures of the twin-screw extruder are set to: 135°C in zone 1, 150°C in zone 2, 160°C in zone 3, 160°C in zone 4, 154°C in zone 5, and 150°C in zone 6. The head temperature of the twin-screw extruder is 150°C, and the screw speed of the twin-screw extruder is 30 r / min.

[0045] The ninth aspect of this patent provides a flame-retardant insulating composite film, and the preparation method of the flame-retardant insulating composite film is: preparing the insulating composite material described in the sixth aspect into a film or a membrane, and then subjecting the film or the membrane to radiation cross-linking or thermal cross-linking treatment to obtain a flame-retardant insulating composite film.

[0046] According to the flame-retardant insulating composite film, preferably, the radiation crosslinking is performed using one or more of ultraviolet radiation, cobalt-60 radiation, X-ray radiation, and electron beam radiation. More preferably, the radiation crosslinking is performed using cobalt-60 radiation, with an irradiation dose of 0.5-10 kGy; more preferably, the irradiation dose is 3 kGy.

[0047] According to the above-mentioned flame-retardant insulating composite film, preferably, the thermal crosslinking is to heat-treat the film or diaphragm at 60-110°C for 1-4 hours; more preferably, in order to improve the effect of thermal crosslinking, when the insulating composite material is prepared into a film or diaphragm, a crosslinking agent (such as DCP, BPO, DTBP, DBHP and other crosslinking agents) can also be added to the raw materials in advance.

[0048] According to the flame-retardant insulating composite film described above, preferably, the insulating composite material is prepared into a film or a membrane by processes such as casting and blow molding.

[0049] Compared with the prior art, the present invention has the following positive and beneficial effects:

[0050] (1) The present invention uses a boron source, a magnesium source, and an aluminum source as raw materials, and adopts a precipitation and deposition method to prepare a boron-magnesium-aluminum ternary complex deposited layer by layer. The structural components of the boron-magnesium-aluminum ternary complex contain magnesium hydroxide, aluminum hydroxide, magnesium borate, aluminum borate, sodium borate, etc. When heated at a high temperature, aluminum hydroxide and magnesium hydroxide will first decompose, and absorb heat and take away heat during the decomposition process, making it more difficult to ignite. The decomposed water can suppress smoke and absorb harmful gases produced by combustion. When the combustion temperature reaches a higher temperature, the decomposed magnesium hydroxide and aluminum hydroxide will become magnesium oxide and aluminum oxide dispersed on the surface of the ignition or the critical surface of the ignition to form an oxide film to isolate oxygen and prevent the continuation of combustion. However, due to the high melting points of magnesium oxide and aluminum oxide, it is difficult to To form a denser molten film, borates such as magnesium borate, aluminum borate, and sodium borate decompose and melt during high-temperature processes to form an oxygen-isolating protective film. Furthermore, they can combine with magnesium oxide and aluminum oxide to form a denser, more heat-resistant or fire-resistant protective film. This is mainly because the relatively low melting point of borates can help flux magnesium oxide and aluminum oxide during melting, allowing them to melt and form films at lower temperatures. Furthermore, during the borate fluxing process, they can form a glass or ceramic body with magnesium oxide and aluminum oxide, creating a more fire-resistant structure. Furthermore, since magnesium oxide and aluminum oxide are themselves good refractory materials, the partial non-melting or combustion temperature that does not reach melting or fluxing can in turn improve the refractory structure and fire-resistant properties of the borate, thereby achieving better oxygen-isolating, fire-resistant, and flame-retardant effects. Furthermore, the synergistic combination of borates and aluminum oxide has the advantage of better obtaining combustion-assisting materials to promote the formation of a carbon film layer, weakening its heat and mass transfer effects, and also playing a flame-retardant role. Furthermore, it can also prevent or reduce molten droplets and reduce the possibility of secondary ignition.

[0051] (2) The present invention uses vinyl tris (2-methoxyethoxy) silane to modify the boron magnesium aluminum complex with a multi-deposition structure. Since the modification process of vinyl tris (2-methoxyethoxy) silane is relatively mild, it will not only not destroy the material and structural changes of the boron magnesium aluminum complex itself, but also better form Si-O bonds with the boron magnesium aluminum complex and firmly gather together to obtain active vinyl groups; using tert-butyl peroxide 2-ethylhexanoate as an initiator, the boron magnesium aluminum complex with vinyl groups is in situ polymerized with vinyl acetate to obtain an in situ composite flame retardant, which is conducive to its fusion processing with organic polymers and has better dispersibility and uniform flame retardant mechanism; using anhydrous ethanol as a solvent is conducive to its ester exchange with vinyl acetate under certain conditions, moderately controlling the progress of the reaction, and can act as a free radical chain transfer agent to transfer free radicals, so that the polymerization degree of vinyl acetate and vinyl boron magnesium aluminum complex can be controlled between appropriate polymerization degrees to obtain slightly lower molecular weight polymers or branched polymers, which is more conducive to the use of boron magnesium aluminum complex in the form of flame retardant masterbatch. In addition, using anhydrous ethanol as a solvent is more environmentally friendly than traditional solvents such as benzene, acetone, methanol, etc., and is relatively healthier for the human body during production and processing operations.

[0052] (3) The in-situ composite flame retardant prepared by the present invention has good compatibility with organic polymers, does not contain sulfur and phosphorus halides, and is environmentally friendly and efficient.

[0053] (4) The present invention uses polyethylene, polyethylene-vinyl acetate, and polyethylene-octene copolymer as the main materials of the matrix material, which have good soft plasticity, touch and comfort in use; and introduces vinyl silane therein, which can not only couple the original matrix material, but also provide better cross-linking groups for subsequent radiation cross-linking, and has a good promoting effect on subsequent material strengthening or cross-linking reaction.

[0054] (5) The flame-retardant insulating composite film of the present invention is prepared by first preparing the insulating composite material into a film or a membrane, and then subjecting the film or the membrane to radiation cross-linking or thermal cross-linking treatment. The material is cross-linked by radiation cross-linking (such as cobalt 60, etc.) or thermal cross-linking, which is green and environmentally friendly, produces almost no residue and toxic substances, and does not introduce irritating or toxic odors; moreover, the prepared composite film has good flame retardancy and insulation, and at the same time has comfortable softness, feel in use, and good foldability, and can be used to prepare soft plastic flame-retardant insulating material products, such as insulating blankets, insulating gloves and insulating clothing. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 The figure is a process flow chart of the method for preparing the flame-retardant insulating composite material of the present invention. DETAILED DESCRIPTION

[0056] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described in detail below.

[0057] Unless otherwise specified, the experimental methods in the following examples are conventional methods and were performed according to the techniques or conditions described in literature in the field or according to product specifications. The materials and reagents used in the following examples were all commercially available unless otherwise specified. The experiments in the following examples were performed in triplicate, and the results were averaged.

[0058] Example 1:

[0059] A boron-magnesium-aluminum composite, a preparation method of the boron-magnesium-aluminum composite (such as Figure 1 The specific steps are as follows:

[0060] (1) adding magnesium chloride to a polyethylene glycol solution, stirring and dissolving the mixture to obtain a mixed solution; dropping a sodium borate solution into the mixed solution, stirring while adding, and continuing to stir and react for 20 minutes after the addition is complete; then dropping a sodium hydroxide solution into the reaction system, stirring while adding, and continuing to stir and react for 20 minutes after the addition is complete; wherein the polyethylene glycol is polyethylene glycol 2000, the mass ratio of the polyethylene glycol to the magnesium chloride is 1:1.5, and the mass fraction of the polyethylene glycol solution is 8%; the mass ratio of the magnesium chloride to the sodium borate is 1:2.12, and the mass fraction of the sodium borate solution is 10%; the mass ratio of the sodium borate to the sodium hydroxide is 1:1.99; and the mass fraction of the sodium hydroxide solution is 10%.

[0061] (2) adding aluminum chloride solution dropwise to the reaction system obtained in step (1) while stirring, and continuing to stir and react for 20 minutes after the addition is completed; then adding sodium hydroxide solution dropwise to the reaction system and stirring and reacting; wherein the mass ratio of the aluminum chloride to the sodium borate is 1.42:1, and the mass fraction of the aluminum chloride solution is 30%; the mass ratio of the sodium hydroxide to the sodium borate is 1.57:1, and the mass fraction of the sodium hydroxide solution is 10%.

[0062] (3) adding an aluminum chloride-magnesium chloride mixture dropwise to the reaction system obtained in step (2) while stirring; continuing to stir the reaction for 30 minutes after the addition is complete; allowing the reaction to stand for 6 hours after the end of the standing; filtering and collecting the precipitate; washing and drying the precipitate to obtain a boron-magnesium-aluminum complex; wherein the mass ratio of the total mass of aluminum chloride and magnesium chloride in the aluminum chloride-magnesium chloride mixture to sodium borate is 1.81:1; and the mass ratio of aluminum chloride to magnesium chloride in the aluminum chloride-magnesium chloride mixture is 1:1.32.

[0063] Example 2:

[0064] An in-situ composite flame retardant, a preparation method of the in-situ composite flame retardant (such as Figure 1 The specific steps are as follows:

[0065] S1. Add the boron magnesium aluminum complex and vinyl tris (2-methoxyethoxy) silane prepared in Example 1 to solvent A, mix well, and obtain a prepolymer mixture; wherein the mass ratio of the vinyl tris (2-methoxyethoxy) silane, the boron magnesium aluminum complex, and the solvent A is 1:1:8; and the solvent A is anhydrous ethanol.

[0066] S2. Add vinyl acetate to solvent B, stir and dissolve at 50°C, then add the prepolymer mixture prepared in step S1, stir and mix, then add tert-butyl peroxide 2-ethylhexanoate, stir and react at 50°C for 30 minutes, then stir and react at 65°C for 4 hours, and then stir and react at 60°C for 2 hours. After the reaction is completed, filter and collect the precipitate, wash and dry the precipitate to obtain an in-situ composite flame retardant; wherein the mass ratio of the vinyl acetate to vinyltri(2-methoxyethoxy)silane is 1:1, the mass ratio of the solvent B to vinyl acetate is 1:5, and the mass ratio of the tert-butyl peroxide 2-ethylhexanoate to vinyl acetate is 0.003:1; and the solvent B is anhydrous ethanol.

[0067] Example 3:

[0068] A flame-retardant insulating composite material, comprising the following raw materials, measured in parts by weight: 14 parts polyethylene, 78 parts ethylene-vinyl acetate copolymer (EVA), 8 parts ethylene-octene copolymer (POE), 2 parts vinyl silane, 1 part dimethyl silicone oil, 10 parts flame retardant, and 0.3 parts antioxidant. The polyethylene is Guangzhou Petrochemical-LLDPE-DFDA7042, the ethylene-vinyl acetate copolymer is Formosa Plastics-EVA-7350M, the ethylene-octene copolymer is Dow's POE8480, the vinyl silane is trivinyl silane, the flame retardant is the in-situ composite flame retardant prepared in Example 2, and the antioxidant is a mixture of antioxidant 1010 and antioxidant 168, wherein the mass ratio of antioxidant 1010 to antioxidant 168 is 2:1.

[0069] The preparation method of the above-mentioned flame-retardant insulating composite material is as follows: polyethylene, ethylene-vinyl acetate copolymer, and ethylene-octene copolymer are mixed uniformly to obtain a mixture; vinyl silane and dimethyl silicone oil are added to the mixture, mixed uniformly, and then an in-situ composite flame retardant and an antioxidant are added. After mixing uniformly, the mixture is added to a twin-screw extruder, melt-blended, extruded, and granulated to obtain the insulating composite material; wherein the temperature of the twin-screw extruder is set to: 135°C in zone 1, 150°C in zone 2, 160°C in zone 3, 160°C in zone 4, 154°C in zone 5, and 150°C in zone 6; the head temperature of the twin-screw extruder is 150°C; and the screw speed of the twin-screw extruder is 30r / min.

[0070] Example 4:

[0071] The content of Example 4 is basically the same as that of Example 3, except that the amount of the in-situ composite flame retardant in the flame retardant insulating composite material is 20 parts.

[0072] Example 5:

[0073] The content of Example 5 is basically the same as that of Example 3, except that the amount of the in-situ composite flame retardant in the flame retardant insulating composite material is 30 parts.

[0074] Example 6:

[0075] The content of Example 6 is basically the same as that of Example 3, except that the amount of the in-situ composite flame retardant in the flame retardant insulating composite material is 40 parts.

[0076] Example 7:

[0077] The content of Example 7 is substantially the same as that of Example 3, except that the amount of the in-situ composite flame retardant in the flame retardant insulating composite material is 30 parts, and the amount of the vinyl silane is 4 parts.

[0078] Example 8:

[0079] The content of Example 8 is basically the same as that of Example 3, except that the amount of the in-situ composite flame retardant in the flame retardant insulating composite material is 30 parts, and the amount of the vinyl silane is 1 part.

[0080] Example 9:

[0081] A boron-magnesium-aluminum composite, wherein the specific steps of the preparation method of the boron-magnesium-aluminum composite are:

[0082] (1) adding magnesium chloride to a polyethylene glycol solution, stirring and dissolving the mixture to obtain a mixed solution; dropping a sodium borate solution into the mixed solution, stirring while adding, and continuing to stir and react for 5 minutes after the addition is complete; then dropping a sodium hydroxide solution into the reaction system, stirring while adding, and continuing to stir and react for 5 minutes after the addition is complete; wherein the polyethylene glycol is polyethylene glycol 2000, the mass ratio of the polyethylene glycol to the magnesium chloride is 1:1, and the mass fraction of the polyethylene glycol solution is 8%; the mass ratio of the magnesium chloride to the sodium borate is 1:2, and the mass fraction of the sodium borate solution is 10%; the mass ratio of the sodium borate to the sodium hydroxide is 1:1.5; and the mass fraction of the sodium hydroxide solution is 10%.

[0083] (2) adding aluminum chloride solution dropwise to the reaction system obtained in step (1) while stirring, and continuing to stir and react for 10 minutes after the addition is completed; then adding sodium hydroxide solution dropwise to the reaction system, stirring and reacting for 10 minutes; wherein the mass ratio of the aluminum chloride to the sodium borate is 1:1, and the mass fraction of the aluminum chloride solution is 30%; the mass ratio of the sodium hydroxide to the sodium borate is 1:1, and the mass fraction of the sodium hydroxide solution is 10%.

[0084] (3) adding an aluminum chloride-magnesium chloride mixture dropwise to the reaction system obtained in step (2) while stirring; continuing to stir the reaction for 20 minutes after the addition is complete; allowing the reaction to stand for 4 hours after the end of the standing; filtering and collecting the precipitate; washing and drying the precipitate to obtain a boron-magnesium-aluminum complex. The mass ratio of the total mass of aluminum chloride and magnesium chloride in the aluminum chloride-magnesium chloride mixture to sodium borate is 1.2:1; and the mass ratio of aluminum chloride to magnesium chloride in the aluminum chloride-magnesium chloride mixture is 1:1.

[0085] Example 10:

[0086] A boron-magnesium-aluminum composite, wherein the specific steps of the preparation method of the boron-magnesium-aluminum composite are:

[0087] (1) Magnesium chloride is added to a polyethylene glycol solution, stirred and dissolved to obtain a mixed solution; sodium borate solution is added dropwise to the mixed solution, stirred while adding dropwise, and the reaction is continued with stirring for 45 minutes after the addition is completed; sodium hydroxide solution is then added dropwise to the reaction system, stirred while adding dropwise, and the reaction is continued with stirring for 45 minutes after the addition is completed; wherein the polyethylene glycol is polyethylene glycol 2000, the mass ratio of the polyethylene glycol to magnesium chloride is 1:2, and the mass fraction of the polyethylene glycol solution is 8%; the mass ratio of the magnesium chloride to sodium borate is 1:3, and the mass fraction of the sodium borate solution is 10%; the mass ratio of the sodium borate to sodium hydroxide is 1:3; and the mass fraction of the sodium hydroxide solution is 10%.

[0088] (2) adding aluminum chloride solution dropwise to the reaction system obtained in step (1) while stirring, and continuing to stir and react for 40 minutes after the addition is completed; then adding sodium hydroxide solution dropwise to the reaction system, stirring and reacting for 40 minutes; wherein the mass ratio of the aluminum chloride to the sodium borate is 2:1, and the mass fraction of the aluminum chloride solution is 30%; the mass ratio of the sodium hydroxide to the sodium borate is 2:1, and the mass fraction of the sodium hydroxide solution is 10%.

[0089] (3) adding an aluminum chloride-magnesium chloride mixture dropwise to the reaction system obtained in step (2) while stirring; continuing to stir the reaction for 60 minutes after the addition is complete; allowing the reaction to stand for 12 hours after the end of the standing; filtering and collecting the precipitate; washing and drying the precipitate to obtain a boron-magnesium-aluminum complex; wherein the mass ratio of the total mass of aluminum chloride and magnesium chloride in the aluminum chloride-magnesium chloride mixture to sodium borate is 2.5:1; and the mass ratio of aluminum chloride to magnesium chloride in the aluminum chloride-magnesium chloride mixture is 1:2.

[0090] Example 11:

[0091] A boron-magnesium-aluminum composite, wherein the specific steps of the preparation method of the boron-magnesium-aluminum composite are:

[0092] (1) adding magnesium chloride to a polyethylene glycol solution, stirring and dissolving the mixture to obtain a mixed solution; dropping a sodium borate solution into the mixed solution, stirring while adding, and continuing to stir and react for 30 minutes after the addition is complete; then dropping a sodium hydroxide solution into the reaction system, stirring while adding, and continuing to stir and react for 30 minutes after the addition is complete; wherein the polyethylene glycol is polyethylene glycol 2000, the mass ratio of the polyethylene glycol to the magnesium chloride is 1:1.5, and the mass fraction of the polyethylene glycol solution is 8%; the mass ratio of the magnesium chloride to the sodium borate is 1:2.5, and the mass fraction of the sodium borate solution is 10%; the mass ratio of the sodium borate to the sodium hydroxide is 1:2; and the mass fraction of the sodium hydroxide solution is 10%.

[0093] (2) adding aluminum chloride solution dropwise to the reaction system obtained in step (1) while stirring, and continuing to stir and react for 20 minutes after the addition is completed; then adding sodium hydroxide solution dropwise to the reaction system, stirring and reacting for 20 minutes; wherein the mass ratio of the aluminum chloride to the sodium borate is 1.5:1, and the molar fraction of the aluminum chloride solution is 30%; the mass ratio of the sodium hydroxide to the sodium borate is 1.5:1, and the mass fraction of the sodium hydroxide solution is 10%.

[0094] (3) adding an aluminum chloride-magnesium chloride mixture dropwise to the reaction system obtained in step (2) while stirring; continuing to stir the reaction for 40 minutes after the addition is complete; allowing the reaction to stand for 8 hours after the end of the standing; filtering and collecting the precipitate; washing and drying the precipitate to obtain a boron-magnesium-aluminum complex. The mass ratio of the total mass of aluminum chloride and magnesium chloride in the aluminum chloride-magnesium chloride mixture to sodium borate is 2:1; and the mass ratio of aluminum chloride to magnesium chloride in the aluminum chloride-magnesium chloride mixture is 1:1.5.

[0095] Example 12:

[0096] A boron-magnesium-aluminum composite, wherein the specific steps of the preparation method of the boron-magnesium-aluminum composite are:

[0097] (1) Magnesium chloride is added to a polyethylene glycol solution, stirred and dissolved to obtain a mixed solution; sodium borate solution is added dropwise to the mixed solution, stirred while adding dropwise, and the reaction is continued with stirring for 25 minutes after the addition is completed; sodium hydroxide solution is then added dropwise to the reaction system, stirred while adding dropwise, and the reaction is continued with stirring for 25 minutes after the addition is completed; wherein the polyethylene glycol is polyethylene glycol 2000, the mass ratio of the polyethylene glycol to magnesium chloride is 1:2, and the mass fraction of the polyethylene glycol solution is 8%; the mass ratio of the magnesium chloride to sodium borate is 1:2, and the mass fraction of the sodium borate solution is 10%; the mass ratio of the sodium borate to sodium hydroxide is 1:2.4; and the mass fraction of the sodium hydroxide solution is 10%.

[0098] (2) adding aluminum chloride solution dropwise to the reaction system obtained in step (1) while stirring, and continuing to stir and react for 40 minutes after the addition is completed; then adding sodium hydroxide solution dropwise to the reaction system, stirring and reacting for 30 minutes; wherein the mass ratio of the aluminum chloride to the sodium borate is 2:1, and the mass fraction of the aluminum chloride solution is 30%; the mass ratio of the sodium hydroxide to the sodium borate is 1.8:1, and the molar fraction of the sodium hydroxide solution is 10%.

[0099] (3) adding an aluminum chloride-magnesium chloride mixture dropwise to the reaction system obtained in step (2) while stirring; continuing to stir the reaction for 30 minutes after the addition is complete; allowing the reaction to stand for 6 hours after the end of the standing; filtering and collecting the precipitate; washing and drying the precipitate to obtain a boron-magnesium-aluminum complex. The mass ratio of the total mass of aluminum chloride and magnesium chloride in the aluminum chloride-magnesium chloride mixture to sodium borate is 1.8:1; and the mass ratio of aluminum chloride to magnesium chloride in the aluminum chloride-magnesium chloride mixture is 1:1.4.

[0100] Example 13:

[0101] A boron-magnesium-aluminum composite, wherein the specific steps of the preparation method of the boron-magnesium-aluminum composite are:

[0102] (1) Magnesium chloride is added to a polyethylene glycol solution, stirred and dissolved to obtain a mixed solution; sodium borate solution is added dropwise to the mixed solution, stirred while adding dropwise, and the reaction is continued with stirring for 35 minutes after the addition is completed; sodium hydroxide solution is then added dropwise to the reaction system, stirred while adding dropwise, and the reaction is continued with stirring for 35 minutes after the addition is completed; wherein the polyethylene glycol is polyethylene glycol 2000, the mass ratio of the polyethylene glycol to magnesium chloride is 1:1.5, and the mass fraction of the polyethylene glycol solution is 8%; the mass ratio of the magnesium chloride to sodium borate is 1:2.2, and the mass fraction of the sodium borate solution is 10%; the mass ratio of the sodium borate to sodium hydroxide is 1:2; and the mass fraction of the sodium hydroxide solution is 10%.

[0103] (2) adding aluminum chloride solution dropwise to the reaction system obtained in step (1) while stirring, and continuing to stir and react for 20 minutes after the addition is completed; then adding sodium hydroxide solution dropwise to the reaction system, stirring and reacting for 30 minutes; wherein the mass ratio of the aluminum chloride to the sodium borate is 1.4:1, and the molar fraction of the aluminum chloride solution is 30%; the mass ratio of the sodium hydroxide to the sodium borate is 1.6:1, and the mass fraction of the sodium hydroxide solution is 10%.

[0104] (3) adding an aluminum chloride-magnesium chloride mixture dropwise to the reaction system obtained in step (2) while stirring; continuing to stir the reaction for 30 minutes after the addition is complete; allowing the reaction to stand for 10 hours after the end of the standing; filtering and collecting the precipitate; washing and drying the precipitate to obtain a boron-magnesium-aluminum complex. The mass ratio of the total mass of aluminum chloride and magnesium chloride in the aluminum chloride-magnesium chloride mixture to sodium borate is 1.8:1; and the mass ratio of aluminum chloride to magnesium chloride in the aluminum chloride-magnesium chloride mixture is 1:1.2.

[0105] Example 14:

[0106] An in-situ composite flame retardant, the specific steps of the preparation method of the in-situ composite flame retardant are:

[0107] S1. Add the boron magnesium aluminum complex prepared in Example 9 and vinyl tris(2-methoxyethoxy)silane to solvent A, mix well, and obtain a prepolymer mixture; wherein the mass ratio of the vinyl tris(2-methoxyethoxy)silane, the boron magnesium aluminum complex, and solvent A is 1:0.2:5; and the solvent A is anhydrous ethanol.

[0108] S2. Add vinyl acetate to solvent B, stir and dissolve at 50°C, then add the prepolymer mixture prepared in step S1, stir and mix, then add tert-butyl peroxide 2-ethylhexanoate, stir and react at 40°C for 60 minutes, then stir and react at 65°C for 2 hours, and then stir and react at 60°C for 2 hours. After the reaction is completed, filter and collect the precipitate, wash and dry the precipitate to obtain an in-situ composite flame retardant; wherein the mass ratio of the vinyl acetate to vinyltris(2-methoxyethoxy)silane is 0.5:1, the mass ratio of the solvent B to vinyl acetate is 1:1, the mass ratio of the tert-butyl peroxide 2-ethylhexanoate to vinyl acetate is 0.001:1, and the solvent B is anhydrous ethanol.

[0109] Example 15:

[0110] An in-situ composite flame retardant, the specific steps of the preparation method of the in-situ composite flame retardant are:

[0111] S1. Add the boron magnesium aluminum complex prepared in Example 10 and vinyl tris(2-methoxyethoxy)silane to solvent A, mix well, and obtain a prepolymer mixture; wherein the mass ratio of the vinyl tris(2-methoxyethoxy)silane, the boron magnesium aluminum complex, and solvent A is 1:1:10; and the solvent A is anhydrous methanol.

[0112] S2. Add vinyl acetate to solvent B, stir and dissolve at 50°C, then add the prepolymer mixture prepared in step S1, stir and mix, then add tert-butyl peroxide 2-ethylhexanoate, stir and react at 55°C for 15 minutes, then stir and react at 65°C for 4 hours, and then stir and react at 60°C for 4 hours. After the reaction is completed, filter and collect the precipitate, wash and dry the precipitate to obtain an in-situ composite flame retardant; wherein the mass ratio of the vinyl acetate to vinyltri(2-methoxyethoxy)silane is (0.5-2):1, the mass ratio of the solvent B to vinyl acetate is 1:10, the mass ratio of the tert-butyl peroxide 2-ethylhexanoate to vinyl acetate is 0.01:1, and the solvent B is methanol.

[0113] Example 16:

[0114] An in-situ composite flame retardant, the specific steps of the preparation method of the in-situ composite flame retardant are:

[0115] S1. Add the boron magnesium aluminum complex and vinyl tris (2-methoxyethoxy) silane prepared in Example 11 to solvent A, mix well, and obtain a prepolymer mixture; wherein the mass ratio of the vinyl tris (2-methoxyethoxy) silane, the boron magnesium aluminum complex, and the solvent A is 1:0.5:6; and the solvent A is dimethyl carbonate.

[0116] S2. Add vinyl acetate to solvent B, stir and dissolve at 50°C, then add the prepolymer mixture prepared in step S1, stir and mix, then add tert-butyl peroxide 2-ethylhexanoate, stir and react at 50°C for 40 minutes, then stir and react at 65°C for 5 hours, and then stir and react at 60°C for 3 hours. After the reaction is completed, filter and collect the precipitate, wash and dry the precipitate to obtain an in-situ composite flame retardant; wherein the mass ratio of the vinyl acetate to vinyltris(2-methoxyethoxy)silane is 1.5:1, the mass ratio of the solvent B to vinyl acetate is 1:8, the mass ratio of the tert-butyl peroxide 2-ethylhexanoate to vinyl acetate is 0.006:1, and the solvent B is dimethyl carbonate.

[0117] Example 17:

[0118] An in-situ composite flame retardant, the specific steps of the preparation method of the in-situ composite flame retardant are:

[0119] S1. Add the boron magnesium aluminum complex and vinyl tris (2-methoxyethoxy) silane prepared in Example 12 to solvent A, mix well, and obtain a prepolymer mixture; wherein the mass ratio of the vinyl tris (2-methoxyethoxy) silane, the boron magnesium aluminum complex, and the solvent A is 1:0.8:8; and the solvent A is acetone.

[0120] S2. Add vinyl acetate to solvent B, stir and dissolve at 50°C, then add the prepolymer mixture prepared in step S1, stir and mix, then add tert-butyl peroxide 2-ethylhexanoate, stir and react at 45°C for 30 minutes, then stir and react at 65°C for 4 hours, and then stir and react at 60°C for 2 hours. After the reaction is completed, filter and collect the precipitate, wash and dry the precipitate to obtain an in-situ composite flame retardant; wherein the mass ratio of the vinyl acetate to vinyltri(2-methoxyethoxy)silane is 1:1, the mass ratio of the solvent B to vinyl acetate is 1:5, the mass ratio of the tert-butyl peroxide 2-ethylhexanoate to vinyl acetate is 0.008:1, and the solvent B is acetone.

[0121] Example 18:

[0122] An in-situ composite flame retardant, the specific steps of the preparation method of the in-situ composite flame retardant are:

[0123] S1. Add the boron magnesium aluminum complex and vinyl tris (2-methoxyethoxy) silane prepared in Example 13 to solvent A, mix well, and obtain a prepolymer mixture; wherein the mass ratio of the vinyl tris (2-methoxyethoxy) silane, the boron magnesium aluminum complex, and the solvent A is 1:1:5; and the solvent A is isopropanol.

[0124] S2, vinyl acetate was added to solvent B, and the mixture was stirred and dissolved at 50°C, and the prepolymer mixture prepared in step S1 was added, and the mixture was stirred and mixed, and tert-butyl peroxide 2-ethylhexanoate was added, and the mixture was stirred and reacted at 40°C for 20 minutes, and then stirred and reacted at 65°C for 4 hours, and then stirred and reacted at 60°C for 2 hours. After the reaction was completed, the mixture was filtered and the precipitate was collected. The precipitate was washed and dried to obtain an in-situ composite flame retardant; wherein the mass ratio of the vinyl acetate to vinyl tris(2-methoxyethoxy) silane was 1.8:1, the mass ratio of the solvent B to vinyl acetate was 1:3, the mass ratio of the tert-butyl peroxide 2-ethylhexanoate to vinyl acetate was (.003:1, and the solvent B was isopropanol.

[0125] Example 19:

[0126] A flame-retardant insulating composite material, comprising the following raw materials, measured in parts by weight: 5 parts polyethylene, 60 parts ethylene-vinyl acetate copolymer, 3 parts ethylene-octene copolymer, 1 part vinyl silane, 1 part dimethyl silicone oil, 10 parts flame retardant, and 0.1 part antioxidant. The polyethylene is Guangzhou Petrochemical-LLDPE-DFDA7042, the ethylene-vinyl acetate copolymer is Formosa Plastics-EVA-7350M, the ethylene-octene copolymer is Dow's POE8480, the vinyl silane is divinyl silane, the flame retardant is the in-situ composite flame retardant prepared in Example 14, and the antioxidant is a mixture of antioxidant 1010 and antioxidant 168, wherein the mass ratio of antioxidant 1010 to antioxidant 168 is 2:1.

[0127] Example 20:

[0128] A flame-retardant insulating composite material, comprising, by weight, 25 parts of polyethylene, 80 parts of ethylene-vinyl acetate copolymer, 15 parts of ethylene-octene copolymer, 5 parts of vinyl silane, 3 parts of dimethyl silicone oil, 40 parts of a flame retardant, and 1 part of an antioxidant. The polyethylene is Guangzhou Petrochemical-LLDPE-DFDA7042, the ethylene-vinyl acetate copolymer is Formosa Plastics-EVA-7350M, the ethylene-octene copolymer is Dow's POE8480, the vinyl silane is trivinyl silane, the flame retardant is the in-situ composite flame retardant prepared in Example 15, and the antioxidant is a mixture of antioxidant 1010 and antioxidant 168, wherein the mass ratio of antioxidant 1010 to antioxidant 168 is 2:1.

[0129] Example 21:

[0130] A flame-retardant insulating composite material, comprising the following raw materials, measured in parts by weight: 20 parts polyethylene, 70 parts ethylene-vinyl acetate copolymer, 10 parts ethylene-octene copolymer, 3 parts vinyl silane, 2 parts dimethyl silicone oil, 20 parts flame retardant, and 0.5 parts antioxidant. The polyethylene is high-density polyethylene with a molecular weight of 200,000-600,000, the ethylene-vinyl acetate copolymer is Yanshan Petrochemical-EVA-18J3, the ethylene-octene copolymer is Dow's POE8480, the vinyl silane is divinyl silane, the flame retardant is the in-situ composite flame retardant prepared in Example 16, and the antioxidant is a mixture of antioxidant 1010 and antioxidant 168, wherein the mass ratio of antioxidant 1010 to antioxidant 168 is 2:1.

[0131] Example 22:

[0132] A flame-retardant insulating composite material, comprising the following raw materials, measured in parts by weight: 10 parts polyethylene, 65 parts ethylene-vinyl acetate copolymer, 12 parts ethylene-octene copolymer, 4 parts vinyl silane, 1 part dimethyl silicone oil, 30 parts flame retardant, and 1 part antioxidant. The polyethylene is Guangzhou Petrochemical-LLDPE-DFDA7042, the ethylene-vinyl acetate copolymer is Formosa Plastics-EVA-7350M, the ethylene-octene copolymer is Dow's POE8480, the vinyl silane is trivinyl silane, the flame retardant is the in-situ composite flame retardant prepared in Example 17, and the antioxidant is a mixture of antioxidant 1010 and antioxidant 168, wherein the mass ratio of antioxidant 1010 to antioxidant 168 is 2:1.

[0133] Example 23:

[0134] A flame-retardant insulating composite material, comprising the following raw materials, measured in parts by weight: 18 parts polyethylene, 80 parts ethylene-vinyl acetate copolymer, 8 parts ethylene-octene copolymer, 4 parts vinyl silane, 2 parts dimethyl silicone oil, 22 parts flame retardant, and 0.4 parts antioxidant. The polyethylene is Guangzhou Petrochemical-LLDPE-DFDA7042, the ethylene-vinyl acetate copolymer is Formosa Plastics-EVA-7350M, the ethylene-octene copolymer is Dow's POE8480, the vinyl silane is trivinyl silane, the flame retardant is the in-situ composite flame retardant prepared in Example 18, and the antioxidant is a mixture of antioxidant 1010 and antioxidant 168, wherein the mass ratio of antioxidant 1010 to antioxidant 168 is 2:1.

[0135] Comparative Example 1:

[0136] The content of Comparative Example 1 is substantially the same as that of Example 3, except that the flame retardant insulating composite material does not contain any flame retardant (ie, the amount of the flame retardant is 0 parts).

[0137] Comparative Example 2:

[0138] The content of Comparative Example 2 is basically the same as Example 3, except that the amount of the in-situ composite flame retardant in the flame retardant insulating composite material formula is 30 parts, and the amount of the vinyl silane is 0 parts (i.e., the flame retardant insulating composite material formula does not contain vinyl silane).

[0139] Comparative Example 3:

[0140] The content of Comparative Example 3 is basically the same as that of Example 3, except that the flame retardant used in the formulation of the flame-retardant insulating composite material is a magnesium-aluminum flame retardant, and the amount of the magnesium-aluminum flame retardant is 30 parts.

[0141] The preparation method of the magnesium-aluminum flame retardant is as follows: adding magnesium chloride and aluminum chloride to a polyethylene glycol solution, stirring and dissolving, and obtaining a mixed solution; then dripping a sodium hydroxide solution into the mixed solution while stirring; continuing to stir and react for 30 minutes after the dripping is complete; standing for 6 hours after the reaction is complete; filtering and collecting the precipitate; washing and drying the precipitate to obtain the magnesium-aluminum flame retardant. The polyethylene glycol is polyethylene glycol 2000, the mass ratio of the polyethylene glycol to magnesium chloride is 1:1.5, and the mass fraction of the polyethylene glycol solution is 8%; the mass ratio of the magnesium chloride to sodium hydroxide is 1:2.4; the mass fraction of the sodium hydroxide solution is 10%; and the mass ratio of the aluminum chloride to magnesium chloride is 1:1.5.

[0142] Comparative Example 4:

[0143] The content of Comparative Example 4 is substantially the same as that of Example 3, except that the flame retardant used in the formulation of the flame-retardant insulating composite material is a magnesium-aluminum flame retardant, and the amount of the magnesium-boron flame retardant is 30 parts.

[0144] The preparation method of the magnesium boron flame retardant is as follows: adding magnesium chloride to a polyethylene glycol solution, stirring and dissolving to obtain a mixed solution; dropping a sodium borate solution into the mixed solution, stirring while adding, and continuing to stir and react for 20 minutes after the addition is complete; then dropping a sodium hydroxide solution into the reaction system, stirring while adding, and continuing to stir and react for 20 minutes after the addition is complete; continuing to stir and react for 30 minutes after the addition is complete, standing for 6 hours after the reaction is completed, filtering, collecting the precipitate, washing and drying the precipitate to obtain the magnesium boron flame retardant. The polyethylene glycol is polyethylene glycol 2000, the mass ratio of the polyethylene glycol to magnesium chloride is 1:1.5, and the mass fraction of the polyethylene glycol solution is 8%; the mass ratio of the magnesium chloride to sodium borate is 1:1.8, and the mass fraction of the sodium borate solution is 10%; the mass ratio of the sodium borate to sodium hydroxide is 1:2.5; and the mass fraction of the sodium hydroxide solution is 10%.

[0145] Comparative Example 5:

[0146] The content of Comparative Example 5 is substantially the same as that of Example 3, except that the flame retardant used in the formulation of the flame-retardant insulating composite material is a magnesium-aluminum flame retardant, and the amount of the magnesium-boron flame retardant is 30 parts.

[0147] Wherein, the preparation method of the boron aluminum flame retardant is:

[0148] (1) adding a sodium borate solution dropwise to a polyethylene glycol solution while stirring, and continuing to stir for 20 minutes after the addition is completed; then adding a sodium hydroxide solution dropwise to the reaction system while stirring, and continuing to stir for 20 minutes after the addition is completed; wherein the polyethylene glycol is polyethylene glycol 2000, and the mass fraction of the polyethylene glycol solution is 8%; the mass ratio of the polyethylene glycol to the sodium borate is 0.67:2.12, and the mass fraction of the sodium borate solution is 10%; the mass ratio of the sodium borate to the sodium hydroxide is 1:1.2; and the mass fraction of the sodium hydroxide solution is 10%.

[0149] (2) adding aluminum chloride solution dropwise to the reaction system obtained in step (1) while stirring; continuing to stir and react for 30 minutes after the addition is completed; standing for 6 hours after the reaction is completed; filtering and collecting the precipitate after standing; washing and drying the precipitate to obtain a boron aluminum flame retardant; wherein the mass ratio of aluminum chloride to sodium borate is 1.42:1, and the mass fraction of the aluminum chloride solution is 30%.

[0150] Comparative Example 6:

[0151] The content of Comparative Example 6 is basically the same as that of Example 3, except that: the amount of the in-situ composite flame retardant in the flame retardant insulating composite material formula is 30 parts, the amount of the ethylene-vinyl acetate copolymer is 100 parts, the amount of the polyethylene is 0 parts (i.e., the flame retardant insulating composite material formula does not contain polyethylene), and the amount of the ethylene-octene copolymer is 0 parts (i.e., the flame retardant insulating composite material formula does not contain ethylene-octene copolymer).

[0152] Comparative Example 7:

[0153] The content of Comparative Example 7 is basically the same as that of Example 3, except that: the amount of the in-situ composite flame retardant in the flame retardant insulating composite material formula is 30 parts, the amount of the polyethylene is 100 parts, the amount of the ethylene-vinyl acetate copolymer is 0 parts (that is, the flame retardant insulating composite material formula does not contain ethylene-vinyl acetate copolymer), and the amount of the ethylene-octene copolymer is 0 parts (that is, the flame retardant insulating composite material formula does not contain ethylene-octene copolymer).

[0154] Comparative Example 8:

[0155] The content of Comparative Example 8 is basically the same as that of Example 3, except that: the amount of the in-situ composite flame retardant in the flame retardant insulating composite material formula is 30 parts, the amount of the ethylene-octene copolymer is 100 parts, the amount of the polyethylene is 0 parts (i.e., the flame retardant insulating composite material formula does not contain polyethylene), and the amount of the ethylene-vinyl acetate copolymer is 0 parts (i.e., the flame retardant insulating composite material formula does not contain ethylene-vinyl acetate copolymer).

[0156] To test the performance of the flame-retardant insulating composite material prepared according to the present invention, the flame-retardant insulating composite materials prepared in Examples 3 to 8 and Comparative Examples 1 to 8 were fabricated into flame-retardant insulating composite films (i.e., insulating blankets). The performance was then compared with an existing high-voltage resin insulating blanket (YS, Japan, named YOTSUGI High-Voltage Resin Insulation Blanket, Model YS241-01-04). The comparison results are shown in Table 1. The flame-retardant insulating composite film was prepared by forming the insulating composite material into a film or diaphragm by a process such as casting or blow molding, and then irradiating and cross-linking the film or diaphragm with cobalt-60 radiation for 3 hours at an irradiation dose of 3 kGy to obtain the flame-retardant insulating composite film.

[0157] Among them, the comfort evaluation method is: based on objective contact or use, a comprehensive evaluation is made from aspects such as texture, touch, smell, roughness, etc., and the grades are divided into excellent, good, qualified, and poor. Poor is not suitable for use.

[0158] Foldability evaluation: The foldability is evaluated based on the total scores of the three foldability indicators, namely, whether the flame retardant insulating composite film is foldable, whether there are creases after folding, and whether the shape can be restored after folding. The higher the total score, the better the foldability, and a total score of 7 or below is considered a failure. The scoring for foldability is as follows: 4 points for foldable, 2 points for only bendable, and 0 point for not foldable. The scoring for creases after folding is as follows: 4 points for no creases, 2 points for slight creases, 1 point for light creases, and 0 point for obvious creases. The scoring for shape restoration after folding is as follows: 4 points for quick shape restoration after folding, 3 points for gradual shape restoration after folding, 2 points for most of the shape restoration after folding, and 1 point for a small part of the shape restoration after folding.

[0159] Table 1 Performance test results of flame retardant insulating composite films prepared using flame retardant composite materials of Examples 3 to 8 and Comparative Examples 1 to 8

[0160]

[0161]

[0162] It can be seen from the performance test results of Examples 3 to 6 and Comparative Example 1 in Table 1 that no in-situ composite flame retardant was added in Comparative Example 1, and the flame retardant insulating composite film prepared therefrom basically had no flame retardancy or had no obvious flame retardancy after ignition; in Examples 3 to 6, with the increase in the amount of the in-situ composite flame retardant, the flammability of the flame retardant insulating composite film basically reached V0 level after the amount of the in-situ composite flame retardant reached 20 parts, and its mechanical properties and withstand voltage performance were relatively stable and did not change much.

[0163] It can be seen from the performance test results of the flame retardant insulating composite film prepared in Example 5 and Comparative Examples 3 to 5 that, under the condition of the same flame retardant dosage, the flame retardant performance of the flame retardant insulating composite film prepared using the in-situ composite flame retardant of the present invention is significantly higher than that of the magnesium-aluminum flame retardant, magnesium-boron flame retardant and boron-aluminum flame retardant, and the mechanical properties, withstand voltage performance and foldability are better.

[0164] From the performance test results of the flame-retardant insulating composite films prepared in Examples 5, 7, 8 and Comparative Example 2, it can be seen that with the increase in the amount of vinyl silane used, the tensile strength, tear force and withstand voltage performance of the prepared composite films are significantly improved, especially their withstand voltage performance. Compared with Comparative Example 2, the withstand voltage performance of Examples 5, 7, and 8 is almost twice or more than that of the sample in Comparative Example 2.

[0165] From the performance test results of the flame retardant insulating composite films prepared in Example 5 and Comparative Examples 6, 7 and 8, it can be seen that the composite films prepared by using ethylene-vinyl acetate copolymer, polyethylene or ethylene-octene copolymer as the main body of the matrix material all have defects; among them, when polyethylene is used alone as the main body of the matrix material, although the tensile strength of the composite film is relatively good, its comfort and foldability are significantly poor, and it is not suitable for preparing soft plastic flame retardant insulating composite materials such as insulating blankets, insulating gloves and insulating clothing; when ethylene-vinyl acetate copolymer or ethylene-octene copolymer is used alone as the main body of the matrix material, the composite film prepared is Although the foldability is good, its tensile strength is obviously poor, which also results in its comfort level barely reaching the qualified level but not reaching the good level. It is too soft and sticky, not only unsuitable for preparing soft plastic flame retardant insulating composite materials such as insulating blankets, insulating gloves, and insulating clothing, but also difficult to process. It is easy to stick to the roller during cast or blown film formation, difficult to cool and form, or the thickness distribution is not uniform. The present invention uses polyethylene, ethylene-vinyl acetate copolymer, and ethylene-octene copolymer in a certain amount of ratio as the main body of the matrix material, as shown in Example 5. The prepared flame retardant insulating composite film has great improvements in use and processing.

[0166] From the performance test results of the composite films prepared in Examples 3 to 8 and Comparative Example 9, it can be seen that the tensile strength, tearing force, and withstand voltage of the flame-retardant insulating composite film prepared using the flame-retardant insulating composite material of the present invention are not much different from those of the existing insulating blanket samples. The existing insulating blanket has a relatively high elongation at break, but it does not have flame retardancy. If a fire occurs, it is not conducive to protecting the environment or individuals.

[0167] The above embodiments are specific implementation methods of the present invention, but the implementation methods of the present invention are not limited to the above embodiments. Any other combination, change, modification, substitution, and simplification that does not exceed the design concept of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A method for preparing a boron-magnesium-aluminum composite, characterized in that: The following steps are involved: (1) adding magnesium chloride to a polyethylene glycol solution, stirring and dissolving the mixture to obtain a mixed solution; dropping a sodium borate solution into the mixed solution, stirring and reacting; then adding a sodium hydroxide solution to the reaction system, stirring and reacting; (2) adding aluminum chloride solution dropwise to the reaction system obtained in step (1) and stirring the reaction; then adding sodium hydroxide solution to the reaction system and stirring the reaction; (3) Adding the aluminum chloride-magnesium chloride mixture dropwise to the reaction system obtained in step (2), stirring for reaction, allowing the mixture to stand after the reaction is completed, filtering and collecting the precipitate, and washing and drying the precipitate to obtain a boron-magnesium-aluminum complex.

2. The preparation method according to claim 1, characterized in that In step (1), the mass ratio of polyethylene glycol to magnesium chloride is 1:(1-2), the mass ratio of magnesium chloride to sodium borate is 1:(2-3), and the mass ratio of sodium borate to sodium hydroxide is 1:(1.5-3); in step (2), the mass ratio of aluminum chloride to sodium borate is (1-2):1, and the mass ratio of sodium hydroxide to sodium borate is (1-2):1; in step (3), the mass ratio of the total mass of aluminum chloride and magnesium chloride in the aluminum chloride-magnesium chloride mixture to sodium borate is (1.2-2.5):1, and the mass ratio of aluminum chloride to magnesium chloride in the aluminum chloride-magnesium chloride mixture is 1:(1-2).

3. A boron-magnesium-aluminum composite prepared by the preparation method according to claim 1 or 2.

4. A method for preparing an in-situ composite flame retardant, characterized in that: The following steps are involved: S1. Add the boron magnesium aluminum complex according to claim 3 and vinyl tris(2-methoxyethoxy)silane to solvent A, mix well, and obtain a prepolymer mixture; S2. Add vinyl acetate to solvent B and stir to dissolve. Then add the prepolymer mixture prepared in step S1 and stir to mix. Then add tert-butyl peroxy 2-ethylhexanoate and stir to react at 40-55° C. for 15-60 min. Then stir to react at 60-65° C. for 4-8 h. After the reaction is completed, filter and collect the precipitate. Wash and dry the precipitate to obtain an in-situ composite flame retardant.

5. The preparation method according to claim 4, characterized in that In step S1, the mass ratio of the vinyl tris (2-methoxyethoxy) silane, the boron magnesium aluminum complex and the solvent A is 1: (0.2-1): (5-10); in step S2, the mass ratio of the vinyl acetate to the vinyl tris (2-methoxyethoxy) silane is (0.5-2): 1, the mass ratio of the solvent B to the vinyl acetate is 1: (1-10), and the mass ratio of the tert-butyl peroxy 2-ethylhexanoate to the vinyl acetate is (0.001-0.01):

1.

6. An in-situ composite flame retardant prepared by the preparation method according to claim 4 or 5.

7. A flame retardant insulating composite material, characterized in that: The flame-retardant insulating composite material contains the in-situ composite flame retardant according to claim 6.

8. The flame-retardant insulating composite material according to claim 7, characterized in that: The flame-retardant insulating composite material is made of the following raw materials by weight: 5-25 parts of polyethylene, 60-80 parts of ethylene-vinyl acetate copolymer, 3-15 parts of ethylene-octene copolymer, 1-5 parts of vinyl silane, 1-3 parts of dimethyl silicone oil, 10-40 parts of in-situ composite flame retardant, and 0.1-1 part of antioxidant.

9. Use of the boron-magnesium-aluminum composite according to claim 3, the in-situ composite flame retardant according to claim 6, or the flame-retardant insulating composite material according to claim 7 or 8 in flame retardants, flame retardant materials, flame retardant insulating materials, and / or insulating products.

10. A flame retardant insulating composite film, characterized in that: The method for preparing the flame-retardant insulating composite film comprises: preparing the insulating composite material according to any one of claims 7 to 8 into a film or a membrane, and then subjecting the film or the membrane to radiation cross-linking or thermal cross-linking treatment to obtain the flame-retardant insulating composite film.

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