Weather-proof flexible fireproof cable and preparation method thereof

Abstract

The invention discloses a weather-proof flexible fireproof cable and a preparation method thereof, and relates to the technical field of cables. The surface of the alumina fiber is firstly plated with titanium, the alumina fiber has excellent fireproof performance, titanium easily forms titanium oxide at high temperature, and the oxide has good stability and fire resistance, so that the fire resistance of the titanium-plated alumina fiber is further improved, the alumina fiber is prevented from being eroded, and the weather resistance of the titanium-plated alumina fiber is enhanced. The nickel silicate has a layered structure, and the layered structure can be used as a protective barrier in flame retardant application, so that the thermal decomposition process of the material is effectively delayed. As a high-temperature-resistant material, nickel has the capability of catalyzing char formation and has better fire resistance. The surface of the titanized alumina fiber is coated with nickel silicate, so that the fireproof performance of the titanized alumina fiber can be further improved.

Description

Technical Field

[0001] The invention relates to the technical field of cables, in particular to a weather-resistant flexible fireproof cable and a preparation method thereof. Background Art

[0002] With the increasing demand for infrastructure such as electricity and communications, various types of cables are increasingly being used. However, cables are subject to multiple challenges from the external environment during use, especially under harsh conditions such as high temperature, humidity, etc., which often seriously affect the performance and service life of cables. Traditional cables often have shortcomings such as poor fire resistance and insufficient weather resistance when facing extreme weather or fire. The structure of ordinary cables is unstable under high temperature or fire conditions, and they are prone to burning or melting. Electricity or communication signals cannot be effectively transmitted in crisis situations such as fire. These problems not only affect the normal use of cables, but may also cause power system failures in emergencies such as fires, and even bring serious safety hazards.

[0003] In order to solve the above problems and improve the weather resistance and fire resistance of the cable, the present invention provides a weather-resistant flexible fire-resistant cable and a preparation method thereof. Summary of the invention

[0004] The object of the present invention is to provide a weather-resistant flexible fire-resistant cable and a preparation method thereof, so as to solve the problems raised in the prior art.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A method for preparing a weather-resistant flexible fire-resistant cable comprises the following steps:

[0007] Step 1: Take the alumina fiber coated with nickel silicate, polypropylene grafted with maleic anhydride, and polypropylene, mix them evenly, melt extrude them, and injection mold them to form a fireproof layer;

[0008] Step 2: Take the alumina fiber coated with nickel silicate, the weather-resistant polyurethane modified acrylic emulsion, and the curing agent, stir them evenly to obtain a protective coating;

[0009] Step 3: Apply the protective coating on the surface of the fireproof layer, irradiate with an ultraviolet lamp with a main wavelength of 365nm, and solidify to obtain a protective layer cover;

[0010] Step 4: Wrap the outer surface of the wire core with an insulating layer, a metal layer, and an anti-puncture layer in sequence, and then cover it with a protective layer to obtain a weather-resistant flexible fire-proof cable;

[0011] The preparation method of the alumina fiber coated with nickel silicate is:

[0012] Take titanium-coated alumina fiber and n-butyl lithium, react at 85-90°C for 4-5h, cool to 25-30°C, filter, wash and dry to obtain compound A; take vinyltrimethoxysilane and ethanol, stir evenly to obtain vinyltrimethoxysilane solution; take nickel chloride hexahydrate and ethanol, stir evenly to obtain nickel chloride hexahydrate solution; take compound A and deionized water, ultrasonicate for 3-5h, add vinyltrimethoxysilane solution, stir for 4-5h, add nickel chloride hexahydrate solution, then add sodium hydroxide solution dropwise, stir for 30-40min, stand for aging, centrifuge, dry and grind to obtain alumina fiber coated with nickel silicate.

[0013] Preferably, the method for preparing the titanium-coated alumina fiber comprises the following steps:

[0014] Step 1: Take alumina fiber, soak it in acetone for 50-70 minutes, take it out, wash it, filter it, oxidize it in an air atmosphere at 400°C for 50-70 minutes, then react it in concentrated nitric acid for 1-2 hours, take it out, wash it, filter it, and dry it to obtain pretreated alumina fiber;

[0015] Step 2: Take acetone and hydrochloric acid, stir evenly to obtain a mixed solution; take alumina fiber and titanium powder, add ethanol, and wet grind to obtain mixture A; then add mixture A to the mixed solution, stir for 10-15 minutes, filter and dry to obtain mixture B, heat mixture B to 800-805°C under argon protection, keep warm for 30-40 minutes, then cool to 25-30°C, sieve to obtain titanium-coated alumina fiber.

[0016] More optimally, the preparation method of the weather-resistant polyurethane modified acrylic emulsion is: take hexamethylene diisocyanate, hydroxyethyl methacrylate, polycarbonate polyol, and xylene, mix them evenly, and react at 80-85°C for 4-5h to obtain a polyurethane prepolymer; take methyl methacrylate, butyl acrylate, glycidyl methacrylate, styrene, isobornyl methacrylate, and dodecyl mercaptan, mix them evenly to obtain a mixed solution; add the mixed solution to xylene at 100°C, add dibenzoyl peroxide, react for 5-6h, add polyurethane prepolymer and di-n-octyltin dithioglycolate, heat to 100°C and react for 1-2h, add dibenzoyl peroxide, react for 1-2h, and evacuate to obtain a weather-resistant polyurethane modified acrylic emulsion.

[0017] More optimally, the fireproof layer is composed of the following substances: 8-10 parts by mass of alumina fibers coated with nickel silicate, 1-3 parts of polypropylene grafted with maleic anhydride, and 60-70 parts of polypropylene.

[0018] More optimally, the protective coating is composed of the following substances: 2-3 parts of alumina fibers coated with nickel silicate, 20-25 parts of weather-resistant polyurethane-modified acrylic emulsion, and 2-4 parts of curing agent, in parts by mass.

[0019] Preferably, the insulating layer is made of any one of polypropylene and polyethylene.

[0020] More optimally, the anti-puncture layer is polyimide cloth.

[0021] More optimally, the particle size of the titanium-coated alumina fiber is 200-250 mesh.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. The present invention first coats titanium on the surface of alumina fiber. Alumina fiber has excellent fire resistance, and titanium easily forms titanium oxide at high temperature. This type of oxide has good stability and fire resistance, thereby further improving the fire resistance of titanium-coated alumina fiber, preventing the alumina fiber from being corroded, and thus enhancing its weather resistance.

[0024] 2. Nickel silicate has a layered structure, which can act as a protective barrier in flame retardant applications, thereby effectively delaying the thermal decomposition process of the material. Nickel, as a high-temperature resistant material, has the ability to catalyze carbonization and has good fire resistance. Coating nickel silicate on the surface of titanium-coated alumina fiber can further improve the fire resistance of titanium-coated alumina fiber.

[0025] 3. The present invention also prepares a weather-resistant polyurethane modified acrylic emulsion, which is used as a protective coating to improve the weather resistance of the cable. The present invention adds vinyl trimethoxy silane when preparing the nickel silicate-coated alumina fiber. Vinyl trimethoxy silane can react with the mercapto group in the weather-resistant polyurethane modified acrylic emulsion, thereby enhancing the crosslinking between the nickel silicate-coated alumina fiber and the weather-resistant polyurethane modified acrylic emulsion, thereby enhancing the weather resistance and flame retardancy of the cable. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The present invention is a structural schematic diagram of a weather-resistant flexible fire-resistant cable. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] There is no specific restriction on the sources and models of the substances involved in the present invention, and illustratively include: polypropylene 5E89: Dongguan Nabaichuan Plastic Chemical Co., Ltd.; polyimide cloth (400g / m2): Guangdong Jingao Special Rope Co., Ltd.; polypropylene grafted maleic anhydride: (grafting rate 1.2%) PO1015: ExxonMobil, USA; curing agent: amine curing agent P304226; polycarbonate polyol: model T5651, which can be purchased from Jining Fangyu Chemical Co., Ltd.; alumina fiber: 20μm.

[0029] Embodiment 1: A method for preparing a weather-resistant flexible fire-resistant cable, comprising the following steps:

[0030] Step 1: Preparation of titanium-coated alumina fibers:

[0031] Take the alumina fiber, soak it in acetone for 60 minutes, take it out, wash it, filter it, oxidize it in an air atmosphere at 400°C for 60 minutes, then react it in 97wt% concentrated nitric acid at 80°C for 1.5 hours, take it out, wash it, filter it, and dry it to obtain the pretreated alumina fiber;

[0032] Take 400 mL of acetone and 60 mL of hydrochloric acid, stir evenly to obtain a mixed solution; take 10 g of alumina fiber and 55 g of 400-mesh titanium powder, add 300 mL of ethanol, and wet grind to obtain a mixture A; then add the mixture A to the mixed solution, stir for 12 minutes, filter, and dry to obtain a mixture B, heat the mixture B to 802°C under argon protection, keep it warm for 35 minutes, then cool it to 28°C, pass it through a 200-mesh sieve, and obtain titanium-coated alumina fiber;

[0033] Step 2: Preparation of alumina fibers coated with nickel silicate:

[0034] Take 2g of titanium-coated alumina fiber and 70mL of 0.5M n-butyl lithium, react at 88°C for 4.5h, cool to 28°C, filter, wash, and dry to obtain compound A; take 0.55g of vinyltrimethoxysilane and 150mL of ethanol, stir evenly to obtain a vinyltrimethoxysilane solution; take 1.5g of nickel chloride hexahydrate and 100mL of ethanol, stir evenly to obtain a nickel chloride hexahydrate solution; take 0.3g of compound A and 500mL of deionized water, ultrasonicate for 4h, add vinyltrimethoxysilane solution, stir for 4.5h, add nickel chloride hexahydrate solution, then drop 35mL of 1M sodium hydroxide solution, stir for 35min, stand for aging, centrifuge, dry, and grind to obtain alumina fiber coated with nickel silicate;

[0035] Step 3: Preparation of weather-resistant polyurethane modified acrylic emulsion:

[0036] Take 85g of hexamethylene diisocyanate, 65g of hydroxyethyl methacrylate, 50g of polycarbonate polyol, and 300mL of xylene, mix them evenly, and react them at 82°C for 4.5h to obtain a polyurethane prepolymer;

[0037] Take 25g of methyl methacrylate, 15g of butyl acrylate, 23g of glycidyl methacrylate, 10g of styrene, 13g of isobornyl methacrylate, and 2g of dodecyl mercaptan, mix well to obtain a mixed solution; add the mixed solution to 300mL of xylene at 100°C, add 7.2g of dibenzoyl peroxide, react for 5.5h, add 54g of polyurethane prepolymer and 5g of di-n-octyltin dithioglycolate, heat to 100°C and react for 1.5h, add 0.7g of dibenzoyl peroxide, react for 1.5h, evacuate, and obtain a weather-resistant polyurethane modified acrylic emulsion;

[0038] Step 4: Preparation of weather-resistant flexible fire-resistant cable:

[0039] S1: Alumina fiber coated with nickel silicate, polypropylene grafted with maleic anhydride, and polypropylene are mixed evenly, melt-extruded, and injection-molded to form a fireproof layer;

[0040] S2: taking alumina fiber coated with nickel silicate, weather-resistant polyurethane-modified acrylic emulsion, and curing agent, and stirring them evenly to obtain a protective coating;

[0041] S3: applying the protective coating on the surface of the fireproof layer, irradiating with an ultraviolet lamp with a main wavelength of 365 nm, and curing to obtain a protective layer cover;

[0042] S4: wrapping the outer surface of the wire core with an insulating layer, a metal layer, and an anti-puncture layer in sequence, and then covering it with a protective layer sleeve to obtain a weather-resistant flexible fire-proof cable;

[0043] The wire core is a copper core; the insulation layer is a polypropylene layer; the metal layer is woven from 0.1 mm galvanized copper wire; the puncture-resistant layer is a polyimide cloth; the thickness of the insulation layer, the metal layer, and the fireproof layer is 3 mm, and the thickness of the coating formed by the protective coating is 200 μm;

[0044] The fireproof layer is composed of the following materials in terms of weight: 9 parts of alumina fiber coated with nickel silicate, 2 parts of polypropylene grafted with maleic anhydride, and 65 parts of polypropylene;

[0045] The protective coating is composed of the following substances in parts by mass: 2.5 parts of alumina fiber coated with nickel silicate, 22 parts of weather-resistant polyurethane modified acrylic emulsion, and 3 parts of curing agent.

[0046] Embodiment 2: A method for preparing a weather-resistant flexible fire-resistant cable, comprising the following steps:

[0047] Step 1: Preparation of titanium-coated alumina fibers:

[0048] Take the alumina fiber, soak it in acetone for 50 minutes, take it out, wash it, filter it, oxidize it in an air atmosphere at 400°C for 50 minutes, then react it in concentrated nitric acid with a concentration of 97wt% at 80°C for 1 hour, take it out, wash it, filter it, and dry it to obtain the pretreated alumina fiber;

[0049] Take 400 mL of acetone and 60 mL of hydrochloric acid, stir evenly to obtain a mixed solution; take 10 g of alumina fiber and 55 g of 400-mesh titanium powder, add 300 mL of ethanol, and wet grind to obtain a mixture A; then add the mixture A to the mixed solution, stir for 10 min, filter, and dry to obtain a mixture B, heat the mixture B to 800° C. under argon protection, keep warm for 30 min, then cool to 25° C., pass through a 200-mesh sieve to obtain titanium-coated alumina fiber;

[0050] Step 2: Preparation of alumina fibers coated with nickel silicate:

[0051] Take 2g of titanium-coated alumina fiber and 70mL of 0.5M n-butyl lithium, react at 85°C for 4h, cool to 25°C, filter, wash, and dry to obtain compound A; take 0.55g of vinyltrimethoxysilane and 150mL of ethanol, stir evenly to obtain a vinyltrimethoxysilane solution; take 1.5g of nickel chloride hexahydrate and 100mL of ethanol, stir evenly to obtain a nickel chloride hexahydrate solution; take 0.3g of compound A and 500mL of deionized water, ultrasonicate for 3h, add vinyltrimethoxysilane solution, stir for 4h, add nickel chloride hexahydrate solution, then add 35mL of 1M sodium hydroxide solution dropwise, stir for 30min, stand for aging, centrifuge, dry, and grind to obtain alumina fiber coated with nickel silicate;

[0052] Step 3: Preparation of weather-resistant polyurethane modified acrylic emulsion:

[0053] Take 85g of hexamethylene diisocyanate, 65g of hydroxyethyl methacrylate, 50g of polycarbonate polyol, and 300mL of xylene, mix them evenly, and react them at 80°C for 4h to obtain a polyurethane prepolymer;

[0054] Take 25g of methyl methacrylate, 15g of butyl acrylate, 23g of glycidyl methacrylate, 10g of styrene, 13g of isobornyl methacrylate, and 2g of dodecyl mercaptan, mix well to obtain a mixed solution; add the mixed solution to 300mL of xylene at 100°C, add 7.2g of dibenzoyl peroxide, react for 5h, add 54g of polyurethane prepolymer and 5g of di-n-octyltin dithioglycolate, heat to 100°C and react for 1h, add 0.7g of dibenzoyl peroxide, react for 1h, and evacuate to obtain a weather-resistant polyurethane modified acrylic emulsion;

[0055] Step 4: Preparation of weather-resistant flexible fire-resistant cable:

[0056] S1: Alumina fiber coated with nickel silicate, polypropylene grafted with maleic anhydride, and polypropylene are mixed evenly, melt-extruded, and injection-molded to form a fireproof layer;

[0057] S2: taking alumina fiber coated with nickel silicate, weather-resistant polyurethane-modified acrylic emulsion, and curing agent, and stirring them evenly to obtain a protective coating;

[0058] S3: applying the protective coating on the surface of the fireproof layer, irradiating with an ultraviolet lamp with a main wavelength of 365 nm, and curing to obtain a protective layer cover;

[0059] S4: wrapping the outer surface of the wire core with an insulating layer, a metal layer, and an anti-puncture layer in sequence, and then covering it with a protective layer sleeve to obtain a weather-resistant flexible fire-proof cable;

[0060] The wire core is a copper core; the insulation layer is a polypropylene layer; the metal layer is woven from 0.1 mm galvanized copper wire; the puncture-resistant layer is a polyimide cloth; the thickness of the insulation layer, the metal layer, and the fireproof layer is 3 mm, and the thickness of the coating formed by the protective coating is 200 μm;

[0061] The fireproof layer is composed of the following materials in terms of weight: 8 parts of alumina fiber coated with nickel silicate, 1 part of polypropylene grafted with maleic anhydride, and 60 parts of polypropylene;

[0062] The protective coating is composed of the following substances in parts by mass: 2 parts of alumina fiber coated with nickel silicate, 20 parts of weather-resistant polyurethane modified acrylic emulsion, and 2 parts of curing agent.

[0063] Embodiment 3: A method for preparing a weather-resistant flexible fire-resistant cable, comprising the following steps:

[0064] Step 1: Preparation of titanium-coated alumina fibers:

[0065] Take the alumina fiber, soak it in acetone for 70 minutes, take it out, wash it, filter it, oxidize it in an air atmosphere at 400°C for 70 minutes, then react it in 97wt% concentrated nitric acid at 80°C for 2 hours, take it out, wash it, filter it, and dry it to obtain the pretreated alumina fiber;

[0066] Take 400 mL of acetone and 60 mL of hydrochloric acid, stir evenly to obtain a mixed solution; take 10 g of alumina fiber and 55 g of 400-mesh titanium powder, add 300 mL of ethanol, and wet grind to obtain a mixture A; then add the mixture A to the mixed solution, stir for 15 min, filter, and dry to obtain a mixture B, heat the mixture B to 805° C. under argon protection, keep warm for 40 min, then cool to 30° C., pass through a 200-mesh sieve to obtain titanium-coated alumina fiber;

[0067] Step 2: Preparation of alumina fibers coated with nickel silicate:

[0068] Take 2g of titanium-coated alumina fiber and 70mL of 0.5M n-butyl lithium, react at 90°C for 5h, cool to 30°C, filter, wash, and dry to obtain compound A; take 0.55g of vinyltrimethoxysilane and 150mL of ethanol, stir evenly to obtain a vinyltrimethoxysilane solution; take 1.5g of nickel chloride hexahydrate and 100mL of ethanol, stir evenly to obtain a nickel chloride hexahydrate solution; take 0.3g of compound A and 500mL of deionized water, ultrasonicate for 5h, add vinyltrimethoxysilane solution, stir for 5h, add nickel chloride hexahydrate solution, then drop 35mL of 1M sodium hydroxide solution, stir for 40min, stand for aging, centrifuge, dry, and grind to obtain alumina fiber coated with nickel silicate;

[0069] Step 3: Preparation of weather-resistant polyurethane modified acrylic emulsion:

[0070] Take 85g of hexamethylene diisocyanate, 65g of hydroxyethyl methacrylate, 50g of polycarbonate polyol, and 300mL of xylene, mix them evenly, and react them at 85°C for 5h to obtain a polyurethane prepolymer;

[0071] Take 25g of methyl methacrylate, 15g of butyl acrylate, 23g of glycidyl methacrylate, 10g of styrene, 13g of isobornyl methacrylate, and 2g of dodecyl mercaptan, mix well to obtain a mixed solution; add the mixed solution to 300mL of xylene at 100°C, add 7.2g of dibenzoyl peroxide, react for 6h, add 54g of polyurethane prepolymer and 5g of di-n-octyltin dithioacetate, heat to 100°C and react for 2h, add 0.7g of dibenzoyl peroxide, react for 2h, and evacuate to obtain a weather-resistant polyurethane modified acrylic emulsion;

[0072] Step 4: Preparation of weather-resistant flexible fire-resistant cable:

[0073] S1: Alumina fiber coated with nickel silicate, polypropylene grafted with maleic anhydride, and polypropylene are mixed evenly, melt-extruded, and injection-molded to form a fireproof layer;

[0074] S2: taking alumina fiber coated with nickel silicate, weather-resistant polyurethane-modified acrylic emulsion, and curing agent, and stirring them evenly to obtain a protective coating;

[0075] S3: applying the protective coating on the surface of the fireproof layer, irradiating with an ultraviolet lamp with a main wavelength of 365 nm, and curing to obtain a protective layer cover;

[0076] S4: wrapping the outer surface of the wire core with an insulating layer, a metal layer, and an anti-puncture layer in sequence, and then covering it with a protective layer sleeve to obtain a weather-resistant flexible fire-proof cable;

[0077] The wire core is a copper core; the insulation layer is a polypropylene layer; the metal layer is woven from 0.1 mm galvanized copper wire; the puncture-resistant layer is a polyimide cloth; the thickness of the insulation layer, the metal layer and the fireproof layer is 3 mm, and the coating thickness formed by the protective coating is 200 μm.

[0078] The fireproof layer is composed of the following substances in terms of mass: 10 parts of alumina fibers coated with nickel silicate, 3 parts of polypropylene grafted with maleic anhydride, and 70 parts of polypropylene.

[0079] The protective coating is composed of the following substances in parts by mass: 3 parts of alumina fiber coated with nickel silicate, 25 parts of weather-resistant polyurethane modified acrylic emulsion, and 4 parts of curing agent.

[0080] Comparative Example 1: No titanium coating was performed on the surface of the alumina fiber, and the rest was the same as in Example 1:

[0081] Step 1: Preparation of alumina fibers coated with nickel silicate:

[0082] Take 2g of alumina fiber and 70mL of 0.5M n-butyl lithium, react at 88°C for 4.5h, cool to 28°C, filter, wash, and dry to obtain compound A; take 0.55g of vinyltrimethoxysilane and 150mL of ethanol, stir evenly to obtain a vinyltrimethoxysilane solution; take 1.5g of nickel chloride hexahydrate and 100mL of ethanol, stir evenly to obtain a nickel chloride hexahydrate solution; take 0.3g of compound A and 500mL of deionized water, ultrasonicate for 4h, add vinyltrimethoxysilane solution, stir for 4.5h, add nickel chloride hexahydrate solution, then drop 35mL of 1M sodium hydroxide solution, stir for 35min, stand for aging, centrifuge, dry, and grind to obtain alumina fiber coated with nickel silicate;

[0083] Step 2: Preparation of weather-resistant polyurethane modified acrylic emulsion:

[0084] Take 85g of hexamethylene diisocyanate, 65g of hydroxyethyl methacrylate, 50g of polycarbonate polyol, and 300mL of xylene, mix them evenly, and react them at 82°C for 4.5h to obtain a polyurethane prepolymer;

[0085] Take 25g of methyl methacrylate, 15g of butyl acrylate, 23g of glycidyl methacrylate, 10g of styrene, 13g of isobornyl methacrylate, and 2g of dodecyl mercaptan, mix well to obtain a mixed solution; add the mixed solution to 300mL of xylene at 100°C, add 7.2g of dibenzoyl peroxide, react for 5.5h, add 54g of polyurethane prepolymer and 5g of di-n-octyltin dithioglycolate, heat to 100°C and react for 1.5h, add 0.7g of dibenzoyl peroxide, react for 1.5h, evacuate, and obtain a weather-resistant polyurethane modified acrylic emulsion;

[0086] Step 3: Preparation of weather-resistant flexible fire-resistant cable:

[0087] S1: Alumina fiber coated with nickel silicate, polypropylene grafted with maleic anhydride, and polypropylene are mixed evenly, melt-extruded, and injection-molded to form a fireproof layer;

[0088] S2: taking alumina fiber coated with nickel silicate, weather-resistant polyurethane-modified acrylic emulsion, and curing agent, and stirring them evenly to obtain a protective coating;

[0089] S3: applying the protective coating on the surface of the fireproof layer, irradiating with an ultraviolet lamp with a main wavelength of 365 nm, and curing to obtain a protective layer cover;

[0090] S4: wrapping the outer surface of the wire core with an insulating layer, a metal layer, and an anti-puncture layer in sequence, and then covering it with a protective layer sleeve to obtain a weather-resistant flexible fire-proof cable;

[0091] The wire core is a copper core; the insulation layer is a polypropylene layer; the metal layer is woven from 0.1 mm galvanized copper wire; the puncture-resistant layer is a polyimide cloth; the thickness of the insulation layer, the metal layer, and the fireproof layer is 3 mm, and the thickness of the coating formed by the protective coating is 200 μm;

[0092] The fireproof layer is composed of the following materials in terms of weight: 9 parts of alumina fiber coated with nickel silicate, 2 parts of polypropylene grafted with maleic anhydride, and 65 parts of polypropylene;

[0093] The protective coating is composed of the following substances in parts by mass: 2.5 parts of alumina fiber coated with nickel silicate, 22 parts of weather-resistant polyurethane modified acrylic emulsion, and 3 parts of curing agent.

[0094] Comparative Example 2: Nickel silicate is not coated on the surface of titanium-coated alumina fiber, and the rest is the same as Example 1:

[0095] Step 1: Preparation of titanium-coated alumina fibers:

[0096] Take the alumina fiber, soak it in acetone for 60 minutes, take it out, wash it, filter it, oxidize it in an air atmosphere at 400°C for 60 minutes, then react it in 97wt% concentrated nitric acid at 80°C for 1.5 hours, take it out, wash it, filter it, and dry it to obtain the pretreated alumina fiber;

[0097] Take 400 mL of acetone and 60 mL of hydrochloric acid, stir evenly to obtain a mixed solution; take 10 g of alumina fiber and 55 g of 400-mesh titanium powder, add 300 mL of ethanol, and wet grind to obtain a mixture A; then add the mixture A to the mixed solution, stir for 12 minutes, filter, and dry to obtain a mixture B, heat the mixture B to 802°C under argon protection, keep it warm for 35 minutes, then cool it to 28°C, pass it through a 200-mesh sieve, and obtain titanium-coated alumina fiber;

[0098] Step 2: Preparation of weather-resistant polyurethane modified acrylic emulsion:

[0099] Take 85g of hexamethylene diisocyanate, 65g of hydroxyethyl methacrylate, 50g of polycarbonate polyol, and 300mL of xylene, mix them evenly, and react them at 82°C for 4.5h to obtain a polyurethane prepolymer;

[0100] Take 25g of methyl methacrylate, 15g of butyl acrylate, 23g of glycidyl methacrylate, 10g of styrene, 13g of isobornyl methacrylate, and 2g of dodecyl mercaptan, mix well to obtain a mixed solution; add the mixed solution to 300mL of xylene at 100°C, add 7.2g of dibenzoyl peroxide, react for 5.5h, add 54g of polyurethane prepolymer and 5g of di-n-octyltin dithioglycolate, heat to 100°C and react for 1.5h, add 0.7g of dibenzoyl peroxide, react for 1.5h, evacuate, and obtain a weather-resistant polyurethane modified acrylic emulsion;

[0101] Step 4: Preparation of weather-resistant flexible fire-resistant cable:

[0102] S1: titanium-coated alumina fiber, polypropylene grafted maleic anhydride, and polypropylene are mixed evenly, melt-extruded, and injection-molded to form a fireproof layer;

[0103] S2: Take titanium-coated alumina fiber, weather-resistant polyurethane-modified acrylic emulsion, and curing agent, stir evenly, and obtain a protective coating;

[0104] S3: applying the protective coating on the surface of the fireproof layer, irradiating with an ultraviolet lamp with a main wavelength of 365 nm, and curing to obtain a protective layer cover;

[0105] S4: wrapping the outer surface of the wire core with an insulating layer, a metal layer, and an anti-puncture layer in sequence, and then covering it with a protective layer sleeve to obtain a weather-resistant flexible fire-proof cable;

[0106] The wire core is a copper core; the insulation layer is a polypropylene layer; the metal layer is woven from 0.1 mm galvanized copper wire; the puncture-resistant layer is a polyimide cloth; the thickness of the insulation layer, the metal layer, and the fireproof layer is 3 mm, and the thickness of the coating formed by the protective coating is 200 μm;

[0107] The fireproof layer is composed of the following materials in terms of weight: 9 parts of titanium-coated alumina fiber, 2 parts of polypropylene grafted maleic anhydride, and 65 parts of polypropylene;

[0108] Calculated by weight, the protective coating consists of the following substances: 2.5 parts of titanium-coated alumina fiber, 22 parts of weather-resistant polyurethane-modified acrylic emulsion, and 3 parts of curing agent.

[0109] Comparative Example 3: No vinyltrimethoxysilane was added, and the rest was the same as Example 1:

[0110] Step 1: Preparation of titanium-coated alumina fibers:

[0111] Take the alumina fiber, soak it in acetone for 60 minutes, take it out, wash it, filter it, oxidize it in an air atmosphere at 400°C for 60 minutes, then react it in 97wt% concentrated nitric acid at 80°C for 1.5 hours, take it out, wash it, filter it, and dry it to obtain the pretreated alumina fiber;

[0112] Take 400 mL of acetone and 60 mL of hydrochloric acid, stir evenly to obtain a mixed solution; take 10 g of alumina fiber and 55 g of 400-mesh titanium powder, add 300 mL of ethanol, and wet grind to obtain a mixture A; then add the mixture A to the mixed solution, stir for 12 minutes, filter, and dry to obtain a mixture B, heat the mixture B to 802°C under argon protection, keep it warm for 35 minutes, then cool it to 28°C, pass it through a 200-mesh sieve, and obtain titanium-coated alumina fiber;

[0113] Step 2: Preparation of alumina fibers coated with nickel silicate:

[0114] Take 2g of titanium-coated alumina fiber and 70mL of 0.5M n-butyl lithium, react at 88°C for 4.5h, cool to 28°C, filter, wash, and dry to obtain compound A; take 1.5g of nickel chloride hexahydrate and 100mL of ethanol, stir evenly to obtain a nickel chloride hexahydrate solution; take 0.3g of compound A and 500mL of deionized water, ultrasonicate for 4h, add the nickel chloride hexahydrate solution, then drop 35mL of 1M sodium hydroxide solution, stir for 35min, stand for aging, centrifuge, dry, and grind to obtain alumina fiber coated with nickel silicate;

[0115] Step 3: Preparation of weather-resistant polyurethane modified acrylic emulsion:

[0116] Take 85g of hexamethylene diisocyanate, 65g of hydroxyethyl methacrylate, 50g of polycarbonate polyol, and 300mL of xylene, mix them evenly, and react them at 82°C for 4.5h to obtain a polyurethane prepolymer;

[0117] Take 25g of methyl methacrylate, 15g of butyl acrylate, 23g of glycidyl methacrylate, 10g of styrene, 13g of isobornyl methacrylate, and 2g of dodecyl mercaptan, mix well to obtain a mixed solution; add the mixed solution to 300mL of xylene at 100°C, add 7.2g of dibenzoyl peroxide, react for 5.5h, add 54g of polyurethane prepolymer and 5g of di-n-octyltin dithioglycolate, heat to 100°C and react for 1.5h, add 0.7g of dibenzoyl peroxide, react for 1.5h, evacuate, and obtain a weather-resistant polyurethane modified acrylic emulsion;

[0118] Step 4: Preparation of weather-resistant flexible fire-resistant cable:

[0119] S1: Alumina fiber coated with nickel silicate, polypropylene grafted with maleic anhydride, and polypropylene are mixed evenly, melt-extruded, and injection-molded to form a fireproof layer;

[0120] S2: taking alumina fiber coated with nickel silicate, weather-resistant polyurethane-modified acrylic emulsion, and curing agent, and stirring them evenly to obtain a protective coating;

[0121] S3: applying the protective coating on the surface of the fireproof layer, irradiating with an ultraviolet lamp with a main wavelength of 365 nm, and curing to obtain a protective layer cover;

[0122] S4: wrapping the outer surface of the wire core with an insulating layer, a metal layer, and an anti-puncture layer in sequence, and then covering it with a protective layer sleeve to obtain a weather-resistant flexible fire-proof cable;

[0123] The wire core is a copper core; the insulation layer is a polypropylene layer; the metal layer is woven from 0.1 mm galvanized copper wire; the puncture-resistant layer is a polyimide cloth; the thickness of the insulation layer, the metal layer, and the fireproof layer is 3 mm, and the thickness of the coating formed by the protective coating is 200 μm;

[0124] The fireproof layer is composed of the following materials in terms of weight: 9 parts of alumina fiber coated with nickel silicate, 2 parts of polypropylene grafted with maleic anhydride, and 65 parts of polypropylene;

[0125] The protective coating is composed of the following substances in parts by mass: 2.5 parts of alumina fiber coated with nickel silicate, 22 parts of weather-resistant polyurethane modified acrylic emulsion, and 3 parts of curing agent.

[0126] experiment:

[0127] The protective layer sleeves prepared in Examples 1 to 3 and Comparative Examples 1 to 3 were cut into samples of 5 cm×1 cm×0.5 cm, and then performance tests were performed; the flame retardant performance test was performed using the limiting oxygen index; the tensile strength of the samples was tested with reference to Part 11 of GB / T2951.11-2008; the samples were placed in an oven at 100° C. for 7 days, and the tensile strength retention rate of each sample after aging was calculated. The obtained data are shown in the following table:

[0128]

[0129] Conclusion: From the comparison of the data in the table, it can be seen that in Comparative Example 1, titanium is not plated on the surface of the alumina fiber, and the weather resistance and flame retardancy of the cable are reduced. In Comparative Example 2, nickel silicate is not coated on the surface of the titanium-plated alumina fiber, and the flame retardancy of the cable is reduced. In Comparative Example 3, vinyl trimethoxy silane is not added, and the weather resistance and flame retardancy of the cable are reduced. In Examples 1 to 3, titanium is plated on the surface of the alumina fiber. The alumina fiber has excellent fire resistance, and titanium easily forms titanium oxide at high temperatures. This type of oxide has good stability and fire resistance, thereby further improving the fire resistance of the titanium-plated alumina fiber, preventing the alumina fiber from being corroded, thereby enhancing its weather resistance. Coating nickel silicate on the surface of the titanium-plated alumina fiber can further improve the fire resistance of the titanium-plated alumina fiber. Vinyl trimethoxy silane can react with the thiol group in the weather-resistant polyurethane modified acrylic emulsion, thereby enhancing the cross-linking between the alumina fiber coated with nickel silicate and the weather-resistant polyurethane modified acrylic emulsion, thereby enhancing the weather resistance and flame retardancy of the cable.

[0130] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A method for preparing a weather-resistant flexible fire-resistant cable, characterized in that: The following steps are involved: Step 1: Take the alumina fiber coated with nickel silicate, polypropylene grafted with maleic anhydride, and polypropylene, mix them evenly, melt extrude them, and injection mold them to form a fireproof layer; Step 2: Take the alumina fiber coated with nickel silicate, the weather-resistant polyurethane modified acrylic emulsion, and the curing agent, stir them evenly to obtain a protective coating; Step 3: Apply the protective coating on the surface of the fireproof layer, irradiate with an ultraviolet lamp with a main wavelength of 365nm, and solidify to obtain a protective layer cover; Step 4: Wrap the outer surface of the wire core with an insulating layer, a metal layer, and an anti-puncture layer in sequence, and then cover it with a protective layer to obtain a weather-resistant flexible fire-proof cable; The preparation method of the alumina fiber coated with nickel silicate is: Take titanium-coated alumina fiber and n-butyl lithium, react at 85-90°C for 4-5h, cool to 25-30°C, filter, wash and dry to obtain compound A; take vinyltrimethoxysilane and ethanol, stir evenly to obtain vinyltrimethoxysilane solution; take nickel chloride hexahydrate and ethanol, stir evenly to obtain nickel chloride hexahydrate solution; take compound A and deionized water, ultrasonicate for 3-5h, add vinyltrimethoxysilane solution, stir for 4-5h, add nickel chloride hexahydrate solution, then add sodium hydroxide solution dropwise, stir for 30-40min, stand for aging, centrifuge, dry and grind to obtain alumina fiber coated with nickel silicate.

2. The method for preparing a weather-resistant flexible fire-resistant cable according to claim 1, characterized in that: The preparation method of the titanium-coated alumina fiber comprises the following steps: Step 1: Take alumina fiber, soak it in acetone for 50-70 minutes, take it out, wash it, filter it, oxidize it in an air atmosphere at 400°C for 50-70 minutes, then react it in concentrated nitric acid for 1-2 hours, take it out, wash it, filter it, and dry it to obtain pretreated alumina fiber; Step 2: Take acetone and hydrochloric acid, stir evenly to obtain a mixed solution; take alumina fiber and titanium powder, add ethanol, and wet grind to obtain mixture A; then add mixture A to the mixed solution, stir for 10-15 minutes, filter and dry to obtain mixture B, heat mixture B to 800-805°C under argon protection, keep warm for 30-40 minutes, then cool to 25-30°C, sieve to obtain titanium-coated alumina fiber.

3. The method for preparing a weather-resistant flexible fire-resistant cable according to claim 1, characterized in that: The preparation method of the weather-resistant polyurethane modified acrylic emulsion comprises the following steps: taking hexamethylene diisocyanate, hydroxyethyl methacrylate, polycarbonate polyol and xylene, mixing them evenly, and reacting them at 80-85°C for 4-5h to obtain a polyurethane prepolymer; taking methyl methacrylate, butyl acrylate, glycidyl methacrylate, styrene, isobornyl methacrylate and dodecyl mercaptan, mixing them evenly to obtain a mixed solution; adding the mixed solution to xylene at 100°C, adding dibenzoyl peroxide, reacting for 5-6h, adding the polyurethane prepolymer and di-n-octyltin bis(thioglycolate), heating to 100°C for reaction for 1-2h, adding dibenzoyl peroxide, reacting for 1-2h, and evacuating to obtain the weather-resistant polyurethane modified acrylic emulsion.

4. The method for preparing a weather-resistant flexible fire-resistant cable according to claim 1, characterized in that: The fireproof layer is composed of the following substances: 8-10 parts of alumina fibers coated with nickel silicate, 1-3 parts of polypropylene grafted with maleic anhydride, and 60-70 parts of polypropylene, calculated by weight.

5. The method for preparing a weather-resistant flexible fire-resistant cable according to claim 1, characterized in that: The protective coating is composed of the following substances: 2-3 parts of alumina fibers coated with nickel silicate, 20-25 parts of weather-resistant polyurethane modified acrylic emulsion, and 2-4 parts of curing agent, calculated by weight.

6. The method for preparing a weather-resistant flexible fire-resistant cable according to claim 1, characterized in that: The insulating layer is any one of polypropylene and polyethylene.

7. The method for preparing a weather-resistant flexible fire-resistant cable according to claim 1, characterized in that: The anti-puncture layer is polyimide cloth.

8. The method for preparing a weather-resistant flexible fire-resistant cable according to claim 2, characterized in that: The particle size of the titanium-coated alumina fiber is 200-250 meshes.

9. A weather-resistant flexible fire-resistant cable prepared according to the method for preparing a weather-resistant flexible fire-resistant cable according to any one of claims 1 to 8.

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