Curved temperature-rising fire-resistant power cable and preparation method thereof

Abstract

The present invention discloses a curve-rise temperature-resistant fire-resistant power cable and a preparation method thereof, and belongs to the technical field of cable preparation. The curve-rise temperature-resistant fire-resistant power cable comprises a conductive core, a filling layer, an armored multimode optical unit and a polyolefin sheath, a plurality of conductive cores are arranged in an annular array inside the polyolefin sheath, the armored multimode optical unit is arranged between the polyolefin sheath and the conductive core, the filling layer is filled between the polyolefin sheath and the conductive core, and the armored multimode optical unit, the conductive core is composed of a copper conductor, a mineral fire-resistant layer and an insulating layer from the inside to the outside, wherein the polyolefin sheath is prepared from a nano halogen-free flame retardant, polyethylene, a modified resin and a compatibilizer. The curve-rise temperature-resistant fire-resistant power cable prepared by the method has excellent flame retardancy, fire resistance and mechanical properties.

Description

Technical Field

[0001] The invention belongs to the technical field of cable preparation, and in particular relates to a curve temperature-rising fire-resistant power cable and a preparation method thereof. Background Art

[0002] As an important carrier of power transmission, the performance of power cables is directly related to the overall efficiency of the power system. When a fire occurs, traditional cables often fail quickly due to being unable to withstand high temperatures, resulting in power outages, which in turn affects the normal operation of key facilities such as fire alarm systems, emergency lighting, and smoke exhaust equipment, exacerbating the severity of the disaster. Therefore, the research and development of power cables with excellent fire resistance has become an important topic in the power industry and scientific research.

[0003] The research on curve heating fire-resistant power cables is based on this background. The design idea of ​​this type of cable is to evaluate and optimize the fire resistance of the cable by simulating the temperature change process in an actual fire, that is, using a curve heating model, so as to more realistically reflect the temperature change characteristics of the fire scene and provide a scientific basis for improving the fire resistance of the cable. Under the curve heating model, fire-resistant power cables not only need to have the ability to maintain normal operation for a long time under high temperature conditions, but also need to maintain the integrity of the line during the flame burning process to prevent the occurrence of short circuits, circuit breaks and other faults.

[0004] Patent CN 103928159 B discloses a fire-resistant power cable, comprising a plurality of conductors, the plurality of conductors are divided into five groups and each group is respectively coated with an insulating layer to form five insulating inner cores, the five insulating inner cores are coated with a ceramic silicone rubber fire-resistant layer, the ceramic silicone rubber fire-resistant layer is filled with alkali-free glass fiber cloth, and the ceramic silicone rubber fire-resistant layer is coated with a silicone rubber inner sheath layer and a steel belt armor layer outer sheath. The invention has a simple structure and has strong fire resistance, and does not affect the overall mechanical properties of the power cable, but the flame retardancy, fire resistance and mechanical properties of the power cable prepared by this method still have room for improvement. Summary of the invention

[0005] The object of the present invention is to provide a curve-heating fire-resistant power cable and a preparation method thereof, so as to solve the technical problem that the flame retardant performance, fire resistance performance and mechanical performance of the cable in the prior art are poor.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] The present invention provides a curved temperature-rising fire-resistant power cable, comprising a conductive core, a filling layer, an armored multimode optical unit and a polyolefin sheath, wherein a plurality of conductive cores are arranged in an annular array inside the polyolefin sheath, the armored multimode optical unit is arranged between the polyolefin sheath and the conductive core, the filling layer is filled between the polyolefin sheath and the conductive core and the armored multimode optical unit, the conductive core is composed of a copper conductor, a mineral fire-resistant layer and an insulating layer from the inside to the outside, the mineral fire-resistant layer is composed of a high-temperature resistant mica tape, the insulating layer is prepared from ceramic polyolefin or ceramic silicone rubber, the high-temperature resistant mica tape is tightly coated on the surface of the copper conductor by mechanical winding, and the ceramic polyolefin or ceramic silicone rubber insulating material is coated on the outside of the mica tape, wherein the polyolefin sheath is prepared from a nano halogen-free flame retardant, polyethylene, a modified resin and a compatibilizer.

[0008] The armored multi-mode optical unit is used as a carrier for temperature and distance measurement. The temperature measurement method is as follows: based on the principle of optical fiber Raman scattering and optical time domain reflectometry positioning, the temperature-sensitive optical cable is used as the front-end temperature sensor. The temperature of each position of the temperature-sensitive optical cable can be accurately measured and the temperature abnormality points can be located. The detection accuracy is high, the consistency and repeatability are good, and it is stable and efficient.

[0009] Preferably, the method for preparing the nano halogen-free flame retardant comprises the following steps:

[0010] Q1: Add aminoethylpiperazine to deionized water and stir until completely dissolved to obtain a piperazine solution. Then add N,N'-methylenebisacrylamide to the piperazine solution, heat to react, concentrate by rotary evaporation, precipitate to obtain a crude product, dissolve the crude product with deionized water, precipitate and purify, repeat the operation, and vacuum dry to obtain compound 1;

[0011] Q2: adding graphene oxide to deionized water, ultrasonically dispersing to obtain a graphene oxide solution, dissolving compound 1 in deionized water, stirring to obtain a compound 1 solution, then adding the graphene oxide solution dropwise to the compound 1 solution, stirring, centrifuging, and washing to obtain compound 2;

[0012] Q3: Compound 2 is added to deionized water, and ultrasonically dispersed to obtain a solution of Compound 2. The solution of Compound 2 is added dropwise to a phytic acid aqueous solution, and stirred, centrifuged, washed, and freeze-dried to obtain a nano halogen-free flame retardant.

[0013] In the above process, aminoethylpiperazine and N,N'-methylenebisacrylamide are first used as raw materials to prepare compound 1 through Michael addition reaction, and then compound 1, phytic acid and graphene oxide are reacted through electrostatic self-assembly to prepare a nano halogen-free flame retardant, wherein the synthesis reaction formula of compound 1 is as follows:

[0014]

[0015] Preferably, in Q1, the molar ratio of aminoethylpiperazine to N,N'-methylenebisacrylamide is (5-10):(4-8), the stirring time until complete dissolution is 5-10 minutes, the heating reaction temperature is 60-70°C, the reaction time is 20-24 hours, the rotary evaporation concentration temperature is 60-65°C, precipitation is carried out in acetone, the operation is repeated 3-5 times, and the vacuum drying temperature is 60-80°C for 20-24 hours.

[0016] Preferably, in Q2, the mass ratio of graphene oxide to compound 1 is (0.3-0.6):(5-10), the ultrasonic dispersion time is 60-90 min, the stirring time is 20-24 h, and ethanol is used for washing.

[0017] Preferably, in Q3, the mass ratio of compound 2 to the phytic acid aqueous solution is (0.3-0.6):(10-20), the ultrasonic dispersion time is 45-60 min, the concentration of the phytic acid aqueous solution is 10 mg / mL, the stirring time is 20-24 h, ethanol is used for washing, and the freeze-drying time is 48-52 h.

[0018] Preferably, the method for preparing the modified resin comprises the following steps:

[0019] S1: adding magnesium chips, methyltriethoxysilane and anhydrous tetrahydrofuran into a container and mixing, then adding iodine, heating under a nitrogen atmosphere, adding 3-benzyloxybromobenzene into anhydrous tetrahydrofuran to obtain a bromobenzene solution, adding a 4% bromobenzene solution into a container, heating, and then dropping the remaining bromobenzene solution into the container, and after the dropping is completed, continuing to stir, distilling under normal pressure, and then adding n-hexane, stirring, standing, settling, collecting the supernatant, concentrating by rotary evaporation to obtain a crude product, and purifying by vacuum distillation to obtain an oily liquid;

[0020] S2: dissolving the oily liquid and methyltriethoxysilane in tetrahydrofuran, stirring, dropping a hydrochloric acid aqueous solution, heating, condensing and refluxing, and after the reflux, rotary evaporation, extraction, washing and drying to obtain a viscous resin;

[0021] S3: Add the viscous resin into a container containing anhydrous tetrahydrofuran, add palladium carbon powder, introduce hydrogen, heat and stir to react, filter and rotary evaporate after the reaction is completed to obtain a light yellow resin;

[0022] S4: Add light yellow resin, 3-nitrophthalonitrile and anhydrous potassium carbonate into a container filled with N,N-dimethylformamide, introduce nitrogen, heat and stir to react, and after the reaction is completed, extract, wash, dry, filter, and rotary evaporate to obtain a modified resin.

[0023] In the above process, 3-benzyloxybromobenzene is first used to protect the hydroxyl group, and then a viscous resin is synthesized by a Grignard reaction. Then, a light yellow resin is prepared by co-hydrolysis condensation and catalytic hydrogenation reduction reaction. Then, 3-nitrophthalonitrile is reacted with the light yellow resin to introduce a phthalonitrile group to obtain a modified resin. The synthetic reaction formula of the modified resin is as follows:

[0024]

[0025] Preferably, in S1, the molar ratio of magnesium chips, methyltriethoxysilane and 3-benzyloxybromobenzene is (1-1.3): (1-1.2): (0.83-1.08), the heating temperature under nitrogen atmosphere is 65-70°C, the heating temperature is 70-80°C, the dropping time is 2-3h, the continued stirring time is 20-24h, and the stirring time is 5-7min; in S2, the molar ratio of the oily liquid and methyltriethoxysilane is (1-2): (1.1-2.1), the concentration of the hydrochloric acid aqueous solution is 1mol / L, the dropping time is 2-4min, the heating condensation reflux temperature is 50-60°C, the reflux time is 20-24h, the extraction is carried out with ethyl acetate, the mixture is washed with distilled water 10-12 times, and the mixture is dried with anhydrous calcium chloride for 20-24h.

[0026] Preferably, in S3, the amount ratio of the viscous resin, anhydrous tetrahydrofuran and palladium carbon powder is (20-40) g: (700-1400) mL: (1.2-2.4) g, the heating and stirring temperature is 40-50°C, and the time is 70-74 h; in S4, the molar ratio of the light yellow resin, 3-nitrophthalonitrile and anhydrous potassium carbonate is (1-2): (1-2): (1.88-3.76), the heating and stirring temperature is 80-90°C, the reaction time is 1-2 h, washed with saturated sodium chloride until neutral, and dried with anhydrous sodium sulfate for 20-24 h.

[0027] Preferably, the method for preparing the curve-heating fire-resistant power cable comprises the following steps:

[0028] Step (1): twisting the copper conductor into a strand, wrapping it with a mica tape, and then extruding and pressing it with a ceramic polyolefin or ceramic silicone rubber insulating material to obtain a conductive wire core;

[0029] Step (2): heating, mixing, stirring, and granulating the nano-halogen-free flame retardant, polyethylene, modified resin, and compatibilizer to obtain a polyolefin sheath material;

[0030] Step (3): twisting the conductive core, wrapping the outer side with a filling layer, burying the armored multi-mode optical unit in the filling layer, wrapping a layer of polyolefin sheath material on the outer side of the filling layer, and after tightly combining, a curve temperature rising fire-resistant power cable is obtained.

[0031] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0032] 1. The present invention first uses aminoethylpiperazine, N,N'-methylenebisacrylamide, graphene oxide and phytic acid as raw materials to prepare a nano halogen-free flame retardant, then uses methyltriethoxysilane, 3-benzyloxybromobenzene and 3-nitrophthalonitrile as raw materials to prepare a modified resin, and the nano halogen-free flame retardant and the modified resin are added to polyethylene at the same time, mixed and reacted to prepare a polyolefin sheath material, which is used in fire-resistant power cables to effectively improve the flame retardancy, fire resistance and mechanical properties of the cables; the mica tape, ceramic polyolefin and silicone rubber material used in the conductive core have excellent fire resistance and heat insulation, and using them as part of the conductive core can effectively improve the fire resistance of the cable; the armored multi-mode optical unit buried in the curve heating fire-resistant power cable can accurately measure the temperature of each position of the cable and locate the temperature abnormality point, so as to achieve the purpose of real-time and online temperature monitoring.

[0033] 2. The present invention uses aminoethylpiperazine, N,N'-methylenebisacrylamide, graphene oxide and phytic acid as raw materials to prepare a nano halogen-free flame retardant that can form a physical barrier in polyethylene, slow down the propagation speed of flame and heat, and delay the combustion process of the material. The N,N'-methylenebisacrylamide and phytic acid contained in the material can decompose under high temperature conditions to produce compounds containing nitrogen, phosphorus and other elements. These compounds can capture free radicals generated by combustion, interrupt the combustion chain reaction, and achieve a flame retardant effect. The nano halogen-free flame retardant is dispersed in polyethylene at nanometer scale, which can significantly improve the strength, toughness and wear resistance of the material. The interaction between the nanoparticles and the polyethylene molecular chains enhances the overall structure of the material.

[0034] 3. The present invention uses methyltriethoxysilane, 3-benzyloxybromobenzene and 3-nitrophthalonitrile as raw materials to prepare a modified resin. The nitrogen and silicon elements contained in the modified resin can form a protective layer or generate flame-retardant gas at high temperature, slow down the propagation speed of the flame, and improve the flame retardant property of polyethylene. The modified resin can undergo a cross-linking reaction with the polyethylene molecular chain to form a tighter network structure that is difficult to be destroyed by the flame, thereby improving the flame retardant and fire-resistant properties of the material. The silane bond contained in the modified resin is a high-bond energy chemical bond with excellent thermal stability and chemical stability. The presence of the silicon element can enable it to form a dense silicon dioxide protective layer at high temperature to prevent the further spread of the flame. The benzene ring contained in the modified resin, as a rigid structural unit, can increase the strength and hardness of the modified resin, and its conjugated effect can also improve the thermal stability of the material. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0036] Figure 1 It is a cross-sectional schematic diagram of the curved temperature-rising fire-resistant power cable prepared by the present invention.

[0037] Description of the drawings: 1-1. Copper conductor; 1-2. Mineral fire-resistant layer; 1-3. Insulation layer; 1. Conductive core; 2. Filling layer; 3. Armored multimode optical unit; 4. Polyolefin sheath. DETAILED DESCRIPTION

[0038] 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.

[0039] Example 1: See Figure 1 As shown, the curved temperature-rising fire-resistant power cable comprises a conductive core 1, a filling layer 2, an armored multimode optical unit 3 and a polyolefin sheath 4, a plurality of conductive cores are arranged in a circular array inside the polyolefin sheath, the armored multimode optical unit is arranged between the polyolefin sheath and the conductive core, the filling layer is filled between the polyolefin sheath and the conductive core and the armored multimode optical unit, and the conductive core is composed of a copper conductor 1-1, a mineral fire-resistant layer 1-2 and an insulating layer 1-3 from the inside to the outside.

[0040] Embodiment 2: This embodiment discloses a method for preparing a nano halogen-free flame retardant, comprising the following steps:

[0041] Q1: Add 29.33 g of aminoethylpiperazine to 300 mL of deionized water, stir for 5 min until completely dissolved to obtain a piperazine solution, then add 27.99 g of N,N'-methylenebisacrylamide to the piperazine solution, heat to 60°C for reaction for 24 h, concentrate by rotary evaporation at 60°C, precipitate in acetone to obtain a crude product, dissolve the crude product in deionized water, precipitate and purify, repeat the operation 5 times, and dry in vacuo at 80°C for 24 h to obtain compound 1;

[0042] Q2: 0.45 g of graphene oxide was added to 10 mL of deionized water, and ultrasonically dispersed for 60 min to obtain a graphene oxide solution. 7.5 g of compound 1 was dissolved in 10 mL of deionized water and stirred to obtain a compound 1 solution. The graphene oxide solution was then added dropwise to the compound 1 solution, stirred for 24 h, centrifuged, and washed with ethanol to obtain compound 2.

[0043] Q3: Add 0.45 g of compound 2 to 10 mL of deionized water, ultrasonically disperse for 60 min to obtain a solution of compound 2, add the solution of compound 2 dropwise to 15 g of a 10 mg / mL phytic acid aqueous solution, stir for 24 h, centrifuge, wash with ethanol, and freeze-dry for 48 h to obtain a nano halogen-free flame retardant.

[0044] This embodiment discloses a method for preparing a modified resin, comprising the following steps:

[0045] S1: 5.10 g of magnesium chips, 35.77 g of methyltriethoxysilane and 80 mL of anhydrous tetrahydrofuran were added to a container and mixed, followed by adding 0.2 g of iodine, and heated to 70° C. under a nitrogen atmosphere. 46.03 g of 3-benzyloxybromobenzene was added to 120 mL of anhydrous tetrahydrofuran to obtain a bromobenzene solution. A 4% bromobenzene solution was added to a container, and after heating to 75° C., the remaining bromobenzene solution was added dropwise to the container for 2 h. After the addition was completed, stirring was continued for 24 h, and distillation was performed under normal pressure. Then, n-hexane was added, and stirring was performed for 7 min. The mixture was allowed to stand for sedimentation, and the supernatant was collected. The crude product was concentrated by rotary evaporation, and purified by vacuum distillation to obtain an oily liquid.

[0046] S2: Dissolve 9g of oily liquid and 5.07g of methyltriethoxysilane in 35mL of tetrahydrofuran, stir, add 8.5mL of 1mol / L hydrochloric acid solution dropwise for 4min, heat to 60℃, condense and reflux for 24h, after reflux, rotary evaporate, extract with ethyl acetate, wash with distilled water 12 times, dry with anhydrous calcium chloride for 24h to obtain a viscous resin;

[0047] S3: Add 30 g of the viscous resin into a container containing 1050 mL of anhydrous tetrahydrofuran, add 1.8 g of palladium carbon powder, introduce hydrogen, heat and stir at 50°C to react for 72 h. After the reaction is completed, filter and rotary evaporate to obtain a light yellow resin;

[0048] S4: Add 8.37 g of light yellow resin, 6.68 g of 3-nitrophthalonitrile and 9.99 g of anhydrous potassium carbonate into a container containing 50 mL of N,N-dimethylformamide, introduce nitrogen, heat and stir at 90°C to react for 2 h. After the reaction is completed, extract, wash with saturated sodium chloride until neutral, dry with anhydrous sodium sulfate for 24 h, filter, and rotary evaporate to obtain a modified resin.

[0049] This embodiment discloses a method for preparing a curve temperature rising fire-resistant power cable, comprising the following steps:

[0050] Step (1): twisting the copper conductor into a strand, wrapping it with a mica tape, and then extruding and pressing it with a ceramic silicone rubber insulation material to obtain a conductive wire core;

[0051] Step (2): heating, mixing, stirring, and granulating the nano-halogen-free flame retardant, polyethylene, modified resin, and compatibilizer to obtain a polyolefin sheath material;

[0052] Step (3): twisting the conductive core, wrapping the outer side with a filling layer, burying the armored multi-mode optical unit in the filling layer, wrapping a layer of polyolefin sheath material on the outer side of the filling layer, and after tightly combining, a curve temperature rising fire-resistant power cable is obtained.

[0053] Embodiment 3: This embodiment discloses a method for preparing a nano halogen-free flame retardant, comprising the following steps:

[0054] Q1: 19.55 g of aminoethylpiperazine was added to 300 mL of deionized water and stirred for 5 min until completely dissolved to obtain a piperazine solution. Subsequently, 18.67 g of N,N'-methylenebisacrylamide was added to the piperazine solution, heated at 60°C for reaction for 24 h, concentrated by rotary evaporation at 60°C, and precipitated in acetone to obtain a crude product. The crude product was dissolved in deionized water, purified by precipitation, and the operation was repeated 5 times. The product was dried under vacuum at 80°C for 24 h to obtain compound 1.

[0055] Q2: 0.3 g of graphene oxide was added to 10 mL of deionized water, and ultrasonically dispersed for 60 min to obtain a graphene oxide solution. 5 g of compound 1 was dissolved in 10 mL of deionized water and stirred to obtain a compound 1 solution. The graphene oxide solution was then added dropwise to the compound 1 solution, stirred for 24 h, centrifuged, and washed with ethanol to obtain compound 2;

[0056] Q3: Add 0.3 g of compound 2 to 10 mL of deionized water, ultrasonically disperse for 60 min to obtain a solution of compound 2, add the solution of compound 2 dropwise to 10 g of a 10 mg / mL phytic acid aqueous solution, stir for 24 h, centrifuge, wash with ethanol, and freeze-dry for 48 h to obtain a nano halogen-free flame retardant.

[0057] This embodiment discloses a method for preparing a modified resin, comprising the following steps:

[0058] S1: 4.43 g of magnesium chips, 32.52 g of methyltriethoxysilane and 80 mL of anhydrous tetrahydrofuran were added to a container and mixed, followed by adding 0.2 g of iodine, and heated to 70° C. under a nitrogen atmosphere. 40 g of 3-benzyloxybromobenzene was added to 120 mL of anhydrous tetrahydrofuran to obtain a bromobenzene solution. A 4% bromobenzene solution was added to a container, and after heating to 75° C., the remaining bromobenzene solution was added dropwise to the container for 2 h. After the addition was completed, stirring was continued for 24 h, and distillation was performed under normal pressure. Then, n-hexane was added, and stirring was performed for 7 min. The mixture was allowed to stand for sedimentation, and the supernatant was collected. The crude product was concentrated by rotary evaporation, and purified by vacuum distillation to obtain an oily liquid.

[0059] S2: Dissolve 6 g of oily liquid and 3.38 g of methyltriethoxysilane in 35 mL of tetrahydrofuran, stir, add 8.5 mL of 1 mol / L hydrochloric acid solution dropwise for 4 min, heat to 60 ° C, condense and reflux for 24 h, after reflux, rotary evaporate, extract with ethyl acetate, wash with distilled water 12 times, and dry with anhydrous calcium chloride for 24 h to obtain a viscous resin;

[0060] S3: Add 20 g of the viscous resin to a container containing 700 mL of anhydrous tetrahydrofuran, add 1.2 g of palladium carbon powder, introduce hydrogen, heat and stir at 50°C to react for 72 h. After the reaction is completed, filter and rotary evaporate to obtain a light yellow resin;

[0061] S4: Add 5.58 g of light yellow resin, 4.45 g of 3-nitrophthalonitrile and 6.66 g of anhydrous potassium carbonate into a container containing 50 mL of N,N-dimethylformamide, introduce nitrogen, heat and stir at 90°C for 2 h. After the reaction is completed, extract, wash with saturated sodium chloride until neutral, dry with anhydrous sodium sulfate for 24 h, filter, and rotary evaporate to obtain a modified resin.

[0062] This embodiment discloses a method for preparing a curve temperature rising fire-resistant power cable, comprising the following steps:

[0063] Step (1): twisting the copper conductor into a strand, wrapping it with a mica tape, and then extruding and pressing it with a ceramic silicone rubber insulation material to obtain a conductive wire core;

[0064] Step (2): heating, mixing, stirring, and granulating the nano-halogen-free flame retardant, polyethylene, modified resin, and compatibilizer to obtain a polyolefin sheath material;

[0065] Step (3): twisting the conductive core, wrapping the outer side with a filling layer, burying the armored multi-mode optical unit in the filling layer, wrapping a layer of polyolefin sheath material on the outer side of the filling layer, and after tightly combining, a curve temperature rising fire-resistant power cable is obtained.

[0066] Embodiment 4: This embodiment discloses a method for preparing a nano halogen-free flame retardant, comprising the following steps:

[0067] Q1: Add 39.1 g of aminoethylpiperazine to 300 mL of deionized water, stir for 5 min until completely dissolved to obtain a piperazine solution, then add 37.3 g of N,N'-methylenebisacrylamide to the piperazine solution, heat to 60°C for reaction for 24 h, concentrate by rotary evaporation at 60°C, precipitate in acetone to obtain a crude product, dissolve the crude product in deionized water, precipitate and purify, repeat the operation 5 times, and dry in vacuo at 80°C for 24 h to obtain compound 1;

[0068] Q2: 0.6 g of graphene oxide was added to 10 mL of deionized water, and ultrasonically dispersed for 60 min to obtain a graphene oxide solution. 10 g of compound 1 was dissolved in 10 mL of deionized water and stirred to obtain a compound 1 solution. The graphene oxide solution was then added dropwise to the compound 1 solution, stirred for 24 h, centrifuged, and washed with ethanol to obtain compound 2.

[0069] Q3: Add 0.6 g of compound 2 to 10 mL of deionized water, ultrasonically disperse for 60 min to obtain a solution of compound 2, add the solution of compound 2 dropwise to 20 g of a 10 mg / mL phytic acid aqueous solution, stir for 24 h, centrifuge, wash with ethanol, and freeze-dry for 48 h to obtain a nano halogen-free flame retardant.

[0070] This embodiment discloses a method for preparing a modified resin, comprising the following steps:

[0071] S1: 5.76 g of magnesium chips, 39.02 g of methyltriethoxysilane and 80 mL of anhydrous tetrahydrofuran were added to a container and mixed, followed by adding 0.2 g of iodine, and heated to 70° C. under a nitrogen atmosphere. 52.05 g of 3-benzyloxybromobenzene was added to 120 mL of anhydrous tetrahydrofuran to obtain a bromobenzene solution. A 4% bromobenzene solution was added to a container, and after heating to 75° C., the remaining bromobenzene solution was added dropwise to the container for 2 h. After the addition was completed, stirring was continued for 24 h, and normal pressure distillation was performed. Then, n-hexane was added, and stirring was performed for 7 min. The mixture was allowed to stand for sedimentation, and the supernatant was collected. The crude product was concentrated by rotary evaporation, and purified by vacuum distillation to obtain an oily liquid.

[0072] S2: Dissolve 12g of oily liquid and 6.76g of methyltriethoxysilane in 35mL of tetrahydrofuran, stir, add 8.5mL of 1mol / L hydrochloric acid solution dropwise for 4min, heat to 60℃, condense and reflux for 24h, after reflux, rotary evaporate, extract with ethyl acetate, wash with distilled water 12 times, dry with anhydrous calcium chloride for 24h to obtain a viscous resin;

[0073] S3: Add 40 g of the viscous resin into a container containing 1400 mL of anhydrous tetrahydrofuran, add 2.4 g of palladium carbon powder, introduce hydrogen, heat and stir at 50°C to react for 72 h. After the reaction is completed, filter and rotary evaporate to obtain a light yellow resin;

[0074] S4: Add 11.16 g of light yellow resin, 8.9 g of 3-nitrophthalonitrile and 13.32 g of anhydrous potassium carbonate into a container containing 50 mL of N,N-dimethylformamide, introduce nitrogen, heat and stir at 90°C for 2 h. After the reaction is completed, extract, wash with saturated sodium chloride until neutral, dry with anhydrous sodium sulfate for 24 h, filter, and rotary evaporate to obtain a modified resin.

[0075] This embodiment discloses a method for preparing a curve temperature rising fire-resistant power cable, comprising the following steps:

[0076] Step (1): twisting the copper conductor into a strand, wrapping it with a mica tape, and then extruding and pressing it with a ceramic silicone rubber insulation material to obtain a conductive wire core;

[0077] Step (2): heating, mixing, stirring, and granulating the nano-halogen-free flame retardant, polyethylene, modified resin, and compatibilizer to obtain a polyolefin sheath material;

[0078] Step (3): twisting the conductive core, wrapping the outer side with a filling layer, burying the armored multi-mode optical unit in the filling layer, wrapping a layer of polyolefin sheath material on the outer side of the filling layer, and after tightly combining, a curve temperature rising fire-resistant power cable is obtained.

[0079] Embodiment 5: This embodiment discloses a method for preparing a nano halogen-free flame retardant, comprising the following steps:

[0080] Q1: Add 24.44 g of aminoethylpiperazine to 300 mL of deionized water and stir for 5 min until completely dissolved to obtain a piperazine solution. Then add 23.33 g of N,N'-methylenebisacrylamide to the piperazine solution, heat to 60°C for reaction for 24 h, concentrate by rotary evaporation at 60°C, precipitate in acetone to obtain a crude product, dissolve the crude product in deionized water, precipitate and purify, repeat the operation 5 times, and dry in vacuo at 80°C for 24 h to obtain compound 1;

[0081] Q2: 0.4 g of graphene oxide was added to 10 mL of deionized water, and ultrasonically dispersed for 60 min to obtain a graphene oxide solution. 8 g of compound 1 was dissolved in 10 mL of deionized water and stirred to obtain a compound 1 solution. The graphene oxide solution was then added dropwise to the compound 1 solution, stirred for 24 h, centrifuged, and washed with ethanol to obtain compound 2;

[0082] Q3: Add 0.4 g of compound 2 to 10 mL of deionized water, ultrasonically disperse for 60 min to obtain a solution of compound 2, add the solution of compound 2 dropwise to 12 g of a 10 mg / mL phytic acid aqueous solution, stir for 24 h, centrifuge, wash with ethanol, and freeze-dry for 48 h to obtain a nano halogen-free flame retardant.

[0083] This embodiment discloses a method for preparing a modified resin, comprising the following steps:

[0084] S1: 4.77 g of magnesium chips, 34.15 g of methyltriethoxysilane and 80 mL of anhydrous tetrahydrofuran were added to a container and mixed, followed by adding 0.2 g of iodine, and heated to 70° C. under a nitrogen atmosphere. 43.02 g of 3-benzyloxybromobenzene was added to 120 mL of anhydrous tetrahydrofuran to obtain a bromobenzene solution. A 4% bromobenzene solution was added to a container, and after heating to 75° C., the remaining bromobenzene solution was added dropwise to the container for 2 h. After the addition was completed, stirring was continued for 24 h, and distillation was performed under normal pressure. Then, n-hexane was added, and stirring was performed for 7 min. The mixture was allowed to stand for sedimentation, and the supernatant was collected. The crude product was concentrated by rotary evaporation, and purified by vacuum distillation to obtain an oily liquid.

[0085] S2: 8 g of oily liquid and 4.23 g of methyltriethoxysilane were dissolved in 35 mL of tetrahydrofuran, stirred, and 8.5 mL of 1 mol / L hydrochloric acid aqueous solution was added dropwise for 4 min, heated to 60 ° C, condensed and refluxed for 24 h, and after reflux, rotary evaporated, extracted with ethyl acetate, washed with distilled water 12 times, and dried with anhydrous calcium chloride for 24 h to obtain a viscous resin;

[0086] S3: Add 25 g of the viscous resin into a container containing 800 mL of anhydrous tetrahydrofuran, add 1.6 g of palladium carbon powder, introduce hydrogen, heat and stir at 50°C to react for 72 h. After the reaction is completed, filter and rotary evaporate to obtain a light yellow resin;

[0087] S4: Add 6.98g of light yellow resin, 5.57g of 3-nitrophthalonitrile and 8.33g of anhydrous potassium carbonate into a container containing 50mL of N,N-dimethylformamide, introduce nitrogen, heat and stir at 90°C for 2h. After the reaction is completed, extract, wash with saturated sodium chloride until neutral, dry with anhydrous sodium sulfate for 24h, filter, and rotary evaporate to obtain a modified resin.

[0088] This embodiment discloses a method for preparing a curve temperature rising fire-resistant power cable, comprising the following steps:

[0089] Step (1): twisting the copper conductor into a strand, wrapping it with a mica tape, and then extruding and pressing it with a ceramic silicone rubber insulation material to obtain a conductive wire core;

[0090] Step (2): heating, mixing, stirring, and granulating the nano-halogen-free flame retardant, polyethylene, modified resin, and compatibilizer to obtain a polyolefin sheath material;

[0091] Step (3): twisting the conductive core, wrapping the outer side with a filling layer, burying the armored multi-mode optical unit in the filling layer, wrapping a layer of polyolefin sheath material on the outer side of the filling layer, and after tightly combining, a curve temperature rising fire-resistant power cable is obtained.

[0092] Comparative Example 1: Compared with Example 2, in the process of preparing the nano halogen-free flame retardant in Comparative Example 1, aminoethylpiperazine is not added, and other conditions remain unchanged.

[0093] Comparative Example 2: Compared with Example 2, in the process of preparing the modified resin in Comparative Example 2, no methyltriethoxysilane was added, and other conditions remained unchanged.

[0094] Comparative Example 3: Compared with Example 2, in the process of preparing the curve-rising temperature fire-resistant power cable in Comparative Example 3, no nano halogen-free flame retardant is added, and other conditions remain unchanged.

[0095] Comparative Example 4: Compared with Example 2, in the process of preparing the curve-rising temperature fire-resistant power cable in Comparative Example 4, no modified resin is added, and other conditions remain unchanged.

[0096] The performance of the curved temperature-rising fire-resistant power cables prepared in Examples 2-5 and Comparative Examples 1-4 was tested. The flame retardant properties of the samples were tested according to GB / T 10707-2008, wherein an oxygen index of less than 22% belongs to a flammable material, an oxygen index between 22% and 27% belongs to a combustible material, and an oxygen index of more than 27% belongs to a flame-retardant material; the thermal stability of the samples was tested according to GB / T 2951.32-2008, the mechanical properties of the samples were tested according to GB / T 2951.11-2008, and the fire resistance of the samples was tested according to Q / NFTC 001-2022 "Test Method for Fire Resistance of Cables under Heating Conditions of Building Fires", and the test results are shown in Table 1:

[0097] Table 1

[0098] project Limiting oxygen index / % Quality difference / mg Elongation at break / % Refractory time / min Example 2 41.3 1.43 486 180 Example 3 41.1 1.48 482 178 Example 4 41.0 1.49 483 177 Example 5 40.9 1.50 481 175 Comparative Example 1 35.5 1.51 467 172 Comparative Example 2 35.2 1.68 466 156 Comparative Example 3 34.0 1.53 452 170 Comparative Example 4 34.1 1.70 451 154

[0099] It can be seen from the test results in Table 1 that the curve-rising fire-resistant power cable prepared by Examples 2-5 of the present invention has excellent flame retardancy, heat resistance, fire resistance and mechanical properties. By comparing Comparative Example 1 with Examples 2-5, it can be seen that the addition of aminoethylpiperazine can effectively improve the flame retardancy and mechanical properties of the curve-rising fire-resistant power cable; by comparing Comparative Example 2 with Examples 2-5, it can be seen that the addition of methyltriethoxysilane can effectively improve the flame retardancy, heat resistance, fire resistance and mechanical properties of the curve-rising fire-resistant power cable; by comparing Comparative Example 3 with Examples 2-5, it can be seen that the addition of nano halogen-free flame retardant can effectively improve the flame retardancy and mechanical properties of the curve-rising fire-resistant power cable; by comparing Comparative Example 4 with Examples 2-5, it can be seen that the addition of modified resin can effectively improve the flame retardancy, heat resistance, fire resistance and mechanical properties of the curve-rising fire-resistant power cable.

[0100] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

[0101] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to only specific implementation methods. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. Curved temperature rising fire-resistant power cable, characterized in that: It comprises a conductive core, a filling layer, an armored multimode optical unit and a polyolefin sheath, wherein a plurality of conductive core annular arrays are arranged inside the polyolefin sheath, the armored multimode optical unit is arranged between the polyolefin sheath and the conductive core, the filling layer is filled between the polyolefin sheath and the conductive core and the armored multimode optical unit, the conductive core is composed of a copper conductor, a mineral fire-resistant layer and an insulating layer from the inside to the outside, the mineral fire-resistant layer is composed of a high-temperature resistant mica tape, the insulating layer is prepared from ceramic polyolefin or ceramic silicone rubber, the high-temperature resistant mica tape is tightly coated on the surface of the copper conductor by mechanical wrapping, and ceramic polyolefin or ceramic silicone rubber insulating material is coated on the outside of the mica tape, wherein the polyolefin sheath is prepared from a nano halogen-free flame retardant, polyethylene, a modified resin and a compatibilizer; The preparation method of the nano halogen-free flame retardant comprises the following steps: Q1: Add aminoethylpiperazine to deionized water and stir until completely dissolved to obtain a piperazine solution. Then add N,N'-methylenebisacrylamide to the piperazine solution, heat to react, concentrate by rotary evaporation, precipitate to obtain a crude product, dissolve the crude product with deionized water, precipitate and purify, repeat the operation, and vacuum dry to obtain compound 1; Q2: adding graphene oxide to deionized water, ultrasonically dispersing to obtain a graphene oxide solution, dissolving compound 1 in deionized water, stirring to obtain a compound 1 solution, then adding the graphene oxide solution dropwise to the compound 1 solution, stirring, centrifuging, and washing to obtain compound 2; Q3: Compound 2 is added to deionized water, ultrasonically dispersed to obtain a solution of Compound 2, and the solution of Compound 2 is added dropwise to a phytic acid aqueous solution, stirred, centrifuged, washed, and freeze-dried to obtain a nano halogen-free flame retardant; The preparation method of the modified resin comprises the following steps: S1: adding magnesium chips, methyltriethoxysilane and anhydrous tetrahydrofuran into a container and mixing, then adding iodine, heating under a nitrogen atmosphere, adding 3-benzyloxybromobenzene into anhydrous tetrahydrofuran to obtain a bromobenzene solution, adding a 4% bromobenzene solution into a container, heating, and then dropping the remaining bromobenzene solution into the container, and after the dropping is completed, continuing to stir, distilling under normal pressure, and then adding n-hexane, stirring, standing, settling, collecting the supernatant, concentrating by rotary evaporation to obtain a crude product, and purifying by vacuum distillation to obtain an oily liquid; S2: dissolving the oily liquid and methyltriethoxysilane in tetrahydrofuran, stirring, dropping a hydrochloric acid aqueous solution, heating, condensing and refluxing, and after the reflux, rotary evaporation, extraction, washing and drying to obtain a viscous resin; S3: Add the viscous resin into a container containing anhydrous tetrahydrofuran, add palladium carbon powder, introduce hydrogen, heat and stir to react, filter and rotary evaporate after the reaction is completed to obtain a light yellow resin; S4: Add light yellow resin, 3-nitrophthalonitrile and anhydrous potassium carbonate into a container filled with N,N-dimethylformamide, introduce nitrogen, heat and stir to react, and after the reaction is completed, extract, wash, dry, filter, and rotary evaporate to obtain a modified resin.

2. The curve temperature rising fire-resistant power cable according to claim 1, characterized in that: In the Q1, the molar ratio of aminoethylpiperazine to N,N'-methylenebisacrylamide is (5-10): (4-8), the stirring time until complete dissolution is 5-10 minutes, the heating reaction temperature is 60-70°C, the reaction time is 20-24 hours, the rotary evaporation concentration temperature is 60-65°C, precipitation is carried out in acetone, the operation is repeated 3-5 times, and the vacuum drying temperature is 60-80°C for 20-24 hours.

3. The curve temperature rising fire-resistant power cable according to claim 1, characterized in that: In Q2, the mass ratio of graphene oxide to compound 1 is (0.3-0.6): (5-10), the ultrasonic dispersion time is 60-90 min, the stirring time after adding the graphene oxide solution dropwise to the compound 1 solution is 20-24 h, and ethanol is used for washing.

4. The curve temperature rising fire-resistant power cable according to claim 1, characterized in that: In Q3, the mass ratio of compound 2 to the phytic acid aqueous solution is (0.3-0.6): (10-20), the ultrasonic dispersion time is 45-60 min, the concentration of the phytic acid aqueous solution is 10 mg / mL, the stirring time is 20-24 h, ethanol is used for washing, and the freeze-drying time is 48-52 h.

5. The curve temperature rising fire-resistant power cable according to claim 1, characterized in that: In the S1, the molar ratio of magnesium chips, methyltriethoxysilane and 3-benzyloxybromobenzene is (1-1.3): (1-1.2): (0.83-1.08), the heating temperature under nitrogen atmosphere is 65-70°C, the heating temperature is 70-80°C, the dropping time is 2-3h, the continuous stirring time is 20-24h, and the stirring time is 5-7min; in the S2, the molar ratio of the oily liquid and methyltriethoxysilane is (1-2): (1.1-2.1), the concentration of the hydrochloric acid aqueous solution is 1mol / L, the dropping time is 2-4min, the heating condensation reflux temperature is 50-60°C, the reflux time is 20-24h, the extraction is carried out with ethyl acetate, the mixture is washed with distilled water 10-12 times, and the mixture is dried with anhydrous calcium chloride for 20-24h.

6. The curve temperature rising fire-resistant power cable according to claim 1, characterized in that: In the S3, the amount ratio of the viscous resin, anhydrous tetrahydrofuran and palladium carbon powder is (20-40) g: (700-1400) mL: (1.2-2.4) g, the heating and stirring temperature is 40-50°C, and the time is 70-74 h; in the S4, the molar ratio of the light yellow resin, 3-nitrophthalonitrile and anhydrous potassium carbonate is (1-2): (1-2): (1.88-3.76), the heating and stirring temperature is 80-90°C, the reaction time is 1-2 h, washed with saturated sodium chloride until neutral, and dried with anhydrous sodium sulfate for 20-24 h.

7. The method for preparing a curve-heating fire-resistant power cable according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step (1): twisting the copper conductor into a strand, wrapping it with a mica tape, and then extruding and pressing it with a ceramic polyolefin or ceramic silicone rubber insulating material to obtain a conductive wire core; Step (2): heating, mixing, stirring, and granulating the nano-halogen-free flame retardant, polyethylene, modified resin, and compatibilizer to obtain a polyolefin sheath material; Step (3): twisting the conductive core, wrapping the outer side with a filling layer, burying the armored multi-mode optical unit in the filling layer, wrapping a layer of polyolefin sheath material on the outer side of the filling layer, and after tightly combining, a curve temperature rising fire-resistant power cable is obtained.

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