Novel fire-resistant wire cable and manufacturing method thereof

Abstract

The invention relates to the technical field of cables, and particularly discloses a novel fire-resistant wire cable and a manufacturing method thereof. The novel fire-resistant wire cable comprises a wire core, a wrapping layer and a protective layer which are sequentially arranged from inside to outside, and further comprises a filler which abuts against the wire core and is arranged in the wrapping layer together with the wire core, and the wire core comprises a conductor, a fire-resistant layer and an insulating layer which are sequentially arranged from inside to outside. The refractory layer is prepared from the following raw materials in parts by weight: 28-30 parts of a binder; 60-70 parts of an inorganic fireproof filler; 20 to 24 parts of a foaming material; 30 to 32 parts of an auxiliary agent; and 8-12 parts of a photoinitiator. The product provided by the invention can be used for an emergency system, and has the advantages of excellent fire resistance, good fire resistance stability and strong flame retardant ability; in addition, the preparation method has the advantage that the preparation time can be greatly shortened.

Description

Technical Field

[0001] The present application relates to the technical field of cables, and in particular to a novel fire-resistant wire and cable and a manufacturing method thereof. Background Art

[0002] Maintaining the integrity of the circuit and the normal operation of the electrical system in emergency situations such as fires is a necessary condition for ensuring the functional safety of key emergency systems. Fire-resistant cables have excellent fire resistance and can maintain safe operation for a certain period of time under flames, which is essential for the normal operation of fire emergency equipment. The main uses include emergency power supply to user fire equipment, fire alarm equipment, ventilation and smoke exhaust equipment, emergency power sockets, emergency elevators and other power supply circuits. These places have extremely high requirements for the reliability and safety of electrical systems. The application of fire-resistant cables can effectively ensure the normal operation of these key systems, which is of great significance to improving the overall safety level.

[0003] CN220367762U discloses a high-performance fireproof cable, the main structure of which is a conductor of multiple copper wires twisted together, a fluorphlogopite tape and an insulating layer are applied to the conductor, multiple wire cores are twisted into a cable and a wrapping layer is prepared, and a halogen-free outer sheath is applied to the cable core. The above structure is a traditional fire-resistant cable, which is wrapped with mica tape, but the mica layer is easily detached during the wrapping process, which damages the fire-resistant performance of the mica tape. The product performance can only be guaranteed by increasing the number of wrapping layers. Therefore, the product cannot take into account both the flexible small outer diameter and the excellent fire-resistant performance. Summary of the invention

[0004] In order to solve the above technical problems, the present application provides a new type of fire-resistant wire and cable and a method for manufacturing the same.

[0005] In the first aspect, the present application provides a new type of fire-resistant wire and cable, comprising a core, a sheath and a protective layer arranged in sequence from the inside to the outside, and also comprising a filler that is in contact with the core and jointly arranged inside the sheath, the core comprising a conductor, a fire-resistant layer and an insulating layer arranged in sequence from the inside to the outside, the raw materials used for the fire-resistant layer comprising the following components in parts by weight: 28-30 parts of a binder; 60-70 parts of an inorganic refractory filler; 20-24 parts of a foaming material; 30-32 parts of an auxiliary agent; 8-12 parts of a photoinitiator, the binder being polyvinyl formal or acrylic resin emulsion, the photoinitiator containing a double absorption peak, with an absorption peak 1 in the range of 270-290nm and an absorption peak 2 in the range of 360-380nm; the raw material used for the insulating layer being any one of polyvinyl chloride, cross-linked polyethylene or polyolefin; the raw material used for the protective layer being any one of polyethylene, flame-retardant polyethylene and low-smoke halogen-free flame-retardant polyolefin.

[0006] Preferably, the inorganic refractory filler includes mica and nano-magnesium oxide.

[0007] Preferably, the auxiliary agent includes antimony trioxide, magnesium hydroxide and nano-montmorillonite.

[0008] In the present application, the weight ratio of mica and nano-magnesium oxide is 3:1, the weight ratio of antimony trioxide, magnesium hydroxide and nano-montmorillonite is 20:70:5, the raw material used for the insulating layer is polyvinyl chloride, and the raw material used for the protective layer is low-smoke halogen-free flame-retardant polyolefin. However, the substances in this application are for illustration only. In actual use, technicians in this field can make adjustments according to actual conditions. Different material ratios and material selections are all included in the protection scope of this application.

[0009] By adopting the above technical scheme, the present application utilizes polyvinyl formal or acrylic resin emulsion, both of which have good bonding force, as the binder in the raw materials used for the refractory layer, and utilizes the characteristics of both of them being able to be UV-cured, assisted by the photoinitiator in the system, so that the refractory layer of the present application can be coated on the surface of the conductor in the form of photocuring, thereby avoiding the problem of damage to the refractory performance caused by the shedding of the mica tape; the present application also adds mica and nano-magnesium oxide as inorganic refractory fillers, which effectively improves the thermal stability, thermal insulation capacity and refractoriness of the refractory layer, and also improves the microstructure density in the refractory layer; the present application also adds a foaming material, which utilizes its porous structure to effectively prevent heat conduction and heat radiation, and can also absorb and buffer thermal stress, thereby improving the thermal stability of the refractory layer; finally, the present application adds a nano-montmorillonite compound of antimony trioxide and magnesium hydroxide as an auxiliary agent, which can play a good flame retardant, smoke suppression, performance enhancement and microstructure improvement effect when the refractory layer is heated and burned, and significantly improves the flame retardant performance, thermal stability and mechanical strength of the refractory layer.

[0010] In general, the fire-resistant layer of the present application has the advantages of excellent fire resistance, good fire resistance stability and strong flame retardancy. The new type of fire-resistant wire and cable finally obtained also has very good fire resistance, flame retardancy and thermal stability. Experimental data show that the cable still maintains insulation without breakdown when applying 3.5kV AC voltage and continuous electric shock for 5 minutes, and still maintains insulation without breakdown when applying 2.4kV AC voltage and continuous electric shock for 4 hours. The maximum elongation under load is 70%, and the permanent elongation after cooling is 0%. After heat treatment at 130°C for 1h, the insulation shrinkage is 1%. In the combustion test, the distance between the lower edge of the upper bracket and the starting point of the carbonized part is 330mm, and the combustion extends downward to the lower edge of the upper bracket by 450mm. Under the conditions of flame temperature of 950-1000°C, fire supply time of 180min, and applied voltage of 1000V, the conductor did not fuse and the voltage remained normal.

[0011] Preferably, the foaming material comprises melamine, pentaerythritol, silane-coated ammonium polyphosphate and expanded graphite, wherein the weight ratio of silane-coated ammonium polyphosphate to expanded graphite is 1:(0.5-1.5).

[0012] Among them, the weight ratio of melamine, pentaerythritol and silane-coated ammonium polyphosphate in the present application is 3:1:1, but the material ratios in the present application are for illustration only. In actual use, those skilled in the art can adjust them according to actual conditions, and different material ratios are included in the protection scope of the present application.

[0013] By adopting the above technical scheme, the present application utilizes melamine and pentaerythritol as foaming materials to form a protective gas and a stable carbonized layer at high temperature to isolate oxygen, and at the same time can also improve the corrosion resistance and crack resistance of the inorganic refractory filler, making it more stable in high temperature and corrosive environment, and reducing the number of cracks formed in the combustion environment; at the same time, a compound of silane-coated ammonium polyphosphate and expanded graphite is utilized, which interact with each other at high temperature to form a dense expansion layer, and at the same time decompose to produce flame-retardant substances, thereby reducing the proportion of combustible substances. Multiple substances cooperate with each other to effectively improve the fire resistance and heat insulation capabilities of the foaming material, thereby optimizing the fire resistance and flame retardancy of the cable. In addition, the present application strictly controls the weight ratio of silane-coated ammonium polyphosphate and expanded graphite to ensure that the expanded graphite can provide an appropriate amount of carbon source during the combustion process, while also ensuring that the silane-coated ammonium polyphosphate can achieve the best effect of releasing flame-retardant substances. Experimental data show that when the weight ratio of silane-coated ammonium polyphosphate and expanded graphite is 1: (0.5-1.5), the fire resistance and flame retardancy of the cable are at a high level.

[0014] In a second aspect, the present application provides a method for manufacturing a novel fire-resistant wire and cable, comprising the following steps: S1. Conductor production: copper wire with a single wire diameter of 2.22-2.23 mm is twisted to form a conductor, and the twisted shape is round, wherein the elongation at break of the copper wire used is 30-35%, and the resistivity is ≤0.017241Ω·mm 2 / m, the final conductor nominal cross-sectional area is 4mm 2 , DC resistance at 20℃≤4.61Ω / km; S2, preparing a refractory layer outside the conductor obtained in the step S1, then carrying out serial production on the outside of the refractory layer, immediately extruding an insulating layer to obtain a wire core, wherein the refractory layer is formed by solidifying a refractory mixture, and the preparation method of the refractory mixture comprises the following steps: stirring a binder, an inorganic refractory filler and an auxiliary agent by weight at a rotation speed of 800-1000r / min for 5min, then adding a foaming material at a rotation speed of 600-800r / min at a feeding speed of 5kg / min, after the addition is completed, mixing the material at a rotation speed of 1200-1400r / min for 5min, then adding a photoinitiator at a rotation speed of 400-600r / min at a feeding speed of 5kg / min, stirring until there is no powder accumulation on the liquid surface, and finally mixing the material at a rotation speed of 1200-1400r / min for 25min to obtain a refractory mixture; S3. Spirally twist the multiple cores obtained in step S2, and set fillers in the gaps between the cores. Then, set a sheath between the fillers and the outside of the cores to ensure that the cores are circumferentially arranged along the inner wall of the sheath and tightly abut against the inner wall of the sheath. Then, set a protective layer on the outside of the sheath to finally obtain a new type of fire-resistant wire and cable.

[0015] By adopting the above technical scheme, the preparation method of the present application utilizes a series production method to prepare the refractory layer and the insulating layer. First, the refractory layer is sprayed and cured. After the refractory layer is coated, it directly enters the extruder for extrusion of the insulating layer, forming a series extrusion method, so that the refractory layer and the insulating layer are completed in the same process, so that the speed of spraying and curing fully reaches the production level of extruded insulation, greatly improving the production efficiency, which can be 5-8 times that of the existing technology. At the same time, the refractory layer is prepared by preheating and shaping the conductor and LED light curing, which maximizes the uniformity and completeness of the refractory layer and improves the stability of the fire resistance and flame retardant properties of the cable.

[0016] Preferably, in the step S1, an antioxidant is also coated on the outside of the conductor, and the antioxidant comprises benzotriazole and 75 wt % ethanol in a weight ratio of (1-1.2):100.

[0017] Preferably, in step S2, the specific steps of preparing the refractory layer are as follows: Preheat the conductor to 87-93°C, heat the refractory mixture for 15-18s and then spray it. The spraying amount is 100-110g / m 2 , sprayed on the conductor The surface is initially shaped, and then the fire-resistant layer is obtained by light curing. The controlled energy of light curing is 800-1000MJ / cm in the UV band. 2 , the light curing line speed is 90-100m / min.

[0018] By adopting the above-mentioned technical scheme, the present application uses a high-pressure spray gun to evenly spray the refractory mixture on the surface of the conductor layer, and is designed with an induction heating method to increase the surface temperature of the conductor layer to shape the refractory mixture, and then uses an LED light curing machine to irradiate and cure to form a complete refractory layer, so that the final refractory layer is denser, and the fire resistance and flame retardant effects are better, and the light curing line speed of 90-100m / min can effectively shorten the processing time.

[0019] Preferably, in step S2, the average thickness of the insulating layer is 0.3-3.0 mm.

[0020] Preferably, in step S3, the average overlap rate of the wrapping layer is not less than 15%, and the minimum overlap rate is not less than 10%.

[0021] Preferably, in step S3, the average thickness of the protective layer is 1.4-5.0 mm.

[0022] By adopting the above technical solution, the present application obtains a finished cable with small size and high fire resistance by strictly controlling the thickness and overlap rate of each layer.

[0023] In summary, this application has the following beneficial technical effects: 1. The fire-resistant layer of the present application has the advantages of excellent fire resistance and good fire resistance stability. The new fire-resistant wire and cable finally obtained also has very good fire resistance, flame retardancy and thermal stability. According to experimental data, the cable still maintains insulation without breakdown when applying 3.5kV AC voltage and continuous electric shock for 5min, and still maintains insulation without breakdown when applying 2.4kV AC voltage and continuous electric shock for 4h. The maximum elongation under load is 70%, the permanent elongation after cooling is 0%, and the insulation shrinkage is 1% after heat treatment at 130℃ for 1h. In the combustion test, the distance between the lower edge of the upper bracket and the starting point of the carbonized part is 330mm, and the combustion extends downward to the lower edge of the upper bracket by 450mm. Under the conditions of flame temperature of 950-1000℃, fire supply time of 180min and applied voltage of 1000V, the conductor does not fuse and the voltage remains normal. 2. The preparation method of the present application utilizes a series production method to prepare the refractory layer and the insulating layer. First, the refractory layer is sprayed and cured. After the refractory layer is coated, it directly enters the extruder for extrusion of the insulating layer, forming a series extrusion method. The refractory layer and the insulating layer are completed in the same process, so that the spraying and curing speeds fully reach the production level of extruded insulation, greatly improving the production efficiency, which can be 5-8 times that of the existing technology. At the same time, the refractory layer is prepared by preheating and shaping the conductor and LED light curing, which maximizes the uniformity and completeness of the refractory layer and improves the stability of the fire resistance and flame retardant properties of the cable. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a cross-sectional view of the present application, and the figure numerals are as follows: 1. wire core; 11. conductor; 12. fire-resistant layer; 13. insulating layer; 2. wrapping layer; 3. protective layer; 4. filler. DETAILED DESCRIPTION

[0025] Material Source Unless otherwise specified, the raw materials used in this application are all commercially available products, specifically: Copper was purchased from Jiangsu Jiangrun Copper Industry, model TU1; Acrylic resin emulsion adhesive, viscosity (100-1000) mPa.s; Mica was purchased from Baofeng Mica, 150-200 mesh; Nano magnesium oxide was purchased from Liaoning Lihe Industrial Co., Ltd.; Magnesium hydroxide was purchased from Aitek Flame Retardant Materials Co., Ltd. Nano-montmorillonite was purchased from Fenghong New Materials Co., Ltd.; Photoinitiator, absorption peak 1 range is 270-290nm, absorption peak 2 range is 360-380nm; Polyvinyl chloride was purchased from Jiangsu Shangshang Cable Group New Materials Co., Ltd., model J-70; Cross-linked polyethylene was purchased from Jiangsu Shangshang Cable Group New Materials Co., Ltd., model YJG-3; Polyvinyl chloride was purchased from Jiangsu Shangshang Cable Group New Materials Co., Ltd., model H-90PVC; Low-smoke halogen-free flame-retardant polyolefin was purchased from Jiangsu Shangshang Cable Group New Materials Co., Ltd., model FU / WH-1 (WH-90 (P201H-FU (orange)); Silane-coated ammonium polyphosphate was purchased from Shifang Changfeng Chemical Co., Ltd., model CF-APP203; Expanded graphite was purchased from Qingdao Tianhe Graphite Co., Ltd., with an expansion coefficient of >220 at 1000°C.

[0026] The present application is further described in detail below in conjunction with embodiments and comparative examples.

[0027] Example 1.1 A method for manufacturing a novel fire-resistant wire and cable comprises the following steps: S1. Conductor production: copper wire with a single wire diameter of 2.22-2.23 mm is twisted to form a conductor, and the twisted shape is round, wherein the elongation at break of the copper wire used is 30-35%, and the resistivity is ≤0.017241Ω·mm 2 / m, the final conductor nominal cross-sectional area is 4mm 2, DC resistance at 20℃≤4.61Ω / km; S21, preparation of refractory mixture: binder (polyvinyl formal), inorganic refractory filler (mica and nano magnesium oxide in a weight ratio of 3: 1) and auxiliary agent (antimony trioxide, magnesium hydroxide and nano montmorillonite in a weight ratio of 20:70:5) were stirred at a speed of 900r / min for 5min, then at a speed of 700r / min, a foaming material (melamine, pentaerythritol and silane-coated ammonium polyphosphate in a weight ratio of 3: 1: 1) was added at a feeding rate of 5kg / min, after the addition was completed, the mixture was homogenized at a speed of 1300r / min for 5min, then at a speed of 500r / min, a photoinitiator was added at a feeding rate of 5kg / min, and the mixture was stirred until there was no powder accumulation on the liquid surface, and finally the mixture was homogenized at a speed of 1300r / min for 25min to obtain a refractory mixture. The specific amounts are shown in Table 1; S22. Preheat the conductor to 90°C and spray the refractory mixture on the conductor surface through 3 sets of high-pressure spray guns. Use special equipment to heat for 16.5s and then spray. The 3 sets of spray guns are placed at 120° and the spraying amount is 105g / m 2 The refractory mixture is sprayed on the conductor surface preheated to 90°C by an induction heater for initial shaping. The light curing machine controls the energy in the UV band to 800-1000MJ / cm 2 range, the light curing line speed is 95m / min, and the fire-resistant layer with a thickness of 0.35mm is obtained; S23, then the tandem production is carried out on the outside of the fire-resistant layer. After the fire-resistant layer is prepared, the insulation layer is immediately extruded on the outside of the fire-resistant layer under the melting effect of the extruder. The insulation material in the injection molding machine is polyvinyl chloride, and a masterbatch is added with a weight ratio of 100:0.4 to polyvinyl chloride. After injection molding, a wire core with an insulation layer prepared is obtained, and the thickness of the insulation layer is 0.7 mm. The wire core is prepared in five different colors, which are achieved by adjusting the masterbatch to be brown, black, gray, blue, and yellow / green double colors; S3, the five wire cores of different colors obtained in step S2 are twisted into a cable in a right-hand back-twisting manner, with a twisted pitch ratio of 30 times, and the center of the cable core is filled with 4 2mm fire-resistant filling ropes and the side gaps are filled with 2 2mm fire-resistant filling ropes to ensure that the overall structure is round, and the wire cores are arranged circumferentially along the inner wall of the wrapping layer and are tightly abutted against the inner wall of the wrapping layer, and then the flame retardant tape is wrapped around the filler and the outer side of the wire core, with an average overlap rate of not less than 15% and a minimum overlap rate of not less than 10%, to obtain a wrapping thickness of The protective layer is then extruded on the outside of the wrapping layer to obtain a protective layer. The protective material in the injection molding machine is low-smoke halogen-free flame-retardant polyolefin. At this time, the temperatures of zones 1 to 8 of the extruder are 125°C, 140°C, 160°C, 160°C, 170°C, 170°C, 180°C and 180°C respectively, the extrusion current of the extruder is 130A, the screw speed of the extruder is not more than 30r / min, the production speed is 35m / min, and finally a new type of fire-resistant wire and cable with a protective layer prepared is obtained, and the thickness of the protective layer is 1.8mm.

[0028] Example 1.2 A method for manufacturing a novel fire-resistant wire and cable comprises the following steps: S1. Conductor production: copper wire with a single wire diameter of 2.22-2.23 mm is twisted to form a conductor, and the twisted shape is round, wherein the elongation at break of the copper wire used is 30-35%, and the resistivity is ≤0.017241Ω·mm 2 / m, the final conductor nominal cross-sectional area is 4mm 2 , DC resistance at 20℃≤4.61Ω / km; S21, preparation of refractory mixture: binder (acrylic resin emulsion), inorganic refractory filler (mica and nano magnesium oxide in a weight ratio of 3: 1) and auxiliary agent (antimony trioxide, magnesium hydroxide and nano montmorillonite in a weight ratio of 20:70:5) were stirred at a speed of 800r / min for 5min, then at a speed of 800r / min, a foaming material (melamine, pentaerythritol and silane-coated ammonium polyphosphate in a weight ratio of 3: 1: 1) was added at a feeding rate of 5kg / min, after the addition was completed, the mixture was homogenized at a speed of 1200r / min for 5min, then at a speed of 600r / min, a photoinitiator was added at a feeding rate of 5kg / min, and the mixture was stirred until there was no powder accumulation on the liquid surface, and finally the mixture was homogenized at a speed of 1400r / min for 25min to obtain a refractory mixture, and the specific amounts are shown in Table 1; S22. Preheat the conductor to 93°C and spray the refractory mixture on the conductor surface through 3 sets of high-pressure spray guns. Use special equipment to heat for 15 seconds and then spray. The 3 sets of spray guns are placed at 120° and the spraying amount is 110g / m 2The refractory mixture is sprayed on the conductor surface preheated to 93°C by the induction heater for initial shaping. The light curing machine controls the energy in the UV band to 800-1000MJ / cm 2 range, the light curing line speed is 100m / min, and the fire-resistant layer with a thickness of 0.3mm is obtained; S23, then the tandem production is carried out on the outside of the fire-resistant layer. After the fire-resistant layer is prepared, the insulation layer is immediately extruded on the outside of the fire-resistant layer under the melting effect of the extruder. The insulation material in the injection molding machine is polyvinyl chloride, and a masterbatch is added with a weight ratio of 100:0.4 to polyvinyl chloride. After injection molding, a wire core with an insulation layer prepared is obtained, and the thickness of the insulation layer is 0.3 mm. The wire core is prepared in five different colors, which are achieved by adjusting the masterbatch to be brown, black, gray, blue, and yellow / green double colors; S3, the five wire cores of different colors obtained in step S2 are twisted into a cable in a right-hand back-twisting manner, with a twisted pitch ratio of 30 times, and the center of the cable core is filled with 4 2mm fire-resistant filling ropes and the side gaps are filled with 2 2mm fire-resistant filling ropes to ensure that the overall structure is round, and the wire cores are arranged circumferentially along the inner wall of the wrapping layer and are tightly abutted against the inner wall of the wrapping layer, and then the flame retardant tape is wrapped around the filler and the outer side of the wire core, with an average overlap rate of not less than 15% and a minimum overlap rate of not less than 10%, to obtain a wrapping thickness of The protective layer is then extruded on the outside of the wrapping layer to obtain a protective layer. The protective material in the injection molding machine is low-smoke halogen-free flame-retardant polyolefin. At this time, the temperatures of zones 1 to 8 of the extruder are 125°C, 140°C, 160°C, 160°C, 170°C, 170°C, 180°C and 180°C respectively, the extrusion current of the extruder is 130A, the screw speed of the extruder is not more than 30r / min, the production speed is 35m / min, and finally a new type of fire-resistant wire and cable with a protective layer prepared is obtained, and the protective layer thickness is 5.0mm.

[0029] Example 1.3 A method for manufacturing a novel fire-resistant wire and cable comprises the following steps: S1. Conductor production: copper wire with a single wire diameter of 2.22-2.23 mm is twisted to form a conductor, and the twisted shape is round, wherein the elongation at break of the copper wire used is 30-35%, and the resistivity is ≤0.017241Ω·mm 2 / m, the final conductor nominal cross-sectional area is 4mm 2 , DC resistance at 20℃≤4.61Ω / km; S21, preparation of refractory mixture: binder (acrylic resin emulsion), inorganic refractory filler (mica and nano magnesium oxide in a weight ratio of 3: 1) and auxiliary agent (antimony trioxide, magnesium hydroxide and nano montmorillonite in a weight ratio of 20:70:5) were stirred at a speed of 1000r / min for 5min, then at a speed of 600r / min, a foaming material (melamine, pentaerythritol and silane-coated ammonium polyphosphate in a weight ratio of 3: 1: 1) was added at a feeding rate of 5kg / min, after the addition was completed, the mixture was homogenized at a speed of 1400r / min for 5min, then at a speed of 400r / min, a photoinitiator was added at a feeding rate of 5kg / min, and the mixture was stirred until there was no powder accumulation on the liquid surface, and finally the mixture was homogenized at a speed of 1200r / min for 25min to obtain a refractory mixture. The specific amounts are shown in Table 1; S22. Preheat the conductor to 87°C and spray the refractory mixture on the conductor surface through 3 sets of high-pressure spray guns. Use special equipment to heat for 18 seconds and then spray. The 3 sets of spray guns are placed at 120° and the spraying amount is 100g / m 2 The refractory mixture is sprayed on the conductor surface preheated to 87°C by the induction heater for initial shaping. The light curing machine controls the energy in the UV band to 800-1000MJ / cm 2 range, the light curing line speed is 90m / min, and the fire-resistant layer with a thickness of 0.4mm is obtained; S23, then the tandem production is carried out on the outside of the fire-resistant layer. After the fire-resistant layer is prepared, the insulation layer is immediately extruded on the outside of the fire-resistant layer under the melting effect of the extruder. The insulation material in the injection molding machine is polyvinyl chloride, and a masterbatch is added with a weight ratio of 100:0.4 to polyvinyl chloride. After injection molding, a wire core with an insulation layer prepared is obtained. The thickness of the insulation layer is 3mm, wherein the wire core is prepared in five different colors, which is achieved by adjusting the masterbatch to be brown, black, gray, blue, and yellow / green double colors; S3, the five wire cores of different colors obtained in step S2 are twisted into a cable in a right-hand back-twisting manner, with a twisted pitch ratio of 30 times, and the center of the cable core is filled with 4 2mm fire-resistant filling ropes and the side gaps are filled with 2 2mm fire-resistant filling ropes to ensure that the overall structure is round, and the wire cores are arranged circumferentially along the inner wall of the wrapping layer and are tightly abutted against the inner wall of the wrapping layer, and then the flame retardant tape is wrapped around the filler and the outer side of the wire core, with an average overlap rate of not less than 15% and a minimum overlap rate of not less than 10%, to obtain a wrapping thickness of The protective layer is then extruded on the outside of the wrapping layer to obtain a protective layer. The protective material in the injection molding machine is low-smoke halogen-free flame-retardant polyolefin. At this time, the temperatures of zones 1 to 8 of the extruder are 125°C, 140°C, 160°C, 160°C, 170°C, 170°C, 180°C and 180°C respectively, the extrusion current of the extruder is 130A, the screw speed of the extruder is not more than 30r / min, the production speed is 35m / min, and finally a new type of fire-resistant wire and cable with a protective layer prepared is obtained, and the thickness of the protective layer is 1.4mm.

[0030] Table 1 Amount of raw materials used for the refractory layer of Example 1 Group Binder Inorganic refractory filler Additives Foam material Photoinitiator Example 1.1 29 65 22 31 10 Example 1.2 28 70 20 32 8 Example 1.3 30 60 24 30 12 Example 2.1 A method for manufacturing a novel fire-resistant wire and cable, which differs from Example 1.1 in that: in step S2, the foaming material is melamine, pentaerythritol, silane-coated ammonium polyphosphate and expanded graphite in a weight ratio of 3:1:1:0.3, and the rest is the same as Example 1.1.

[0031] Example 2.2 A method for manufacturing a novel fire-resistant wire and cable, which differs from Example 1.1 in that: in step S2, the foaming material is melamine, pentaerythritol, silane-coated ammonium polyphosphate and expanded graphite in a weight ratio of 3:1:1:0.5, and the rest is the same as Example 1.1.

[0032] Example 2.3 A method for manufacturing a novel fire-resistant wire and cable, which differs from Example 1.1 in that: in step S2, the foaming material is melamine, pentaerythritol, silane-coated ammonium polyphosphate and expanded graphite in a weight ratio of 3:1:1:1.0, and the rest is the same as Example 1.1.

[0033] Example 2.4 A method for manufacturing a novel fire-resistant wire and cable, which differs from Example 1.1 in that: in step S2, the foaming material is melamine, pentaerythritol, silane-coated ammonium polyphosphate and expanded graphite in a weight ratio of 3:1:1:1.5, and the rest is the same as Example 1.1.

[0034] Example 2.5 A method for manufacturing a novel fire-resistant wire and cable, which differs from Example 1.1 in that: in step S2, the foaming material is melamine, pentaerythritol, silane-coated ammonium polyphosphate and expanded graphite in a weight ratio of 3:1:1:2, and the rest is the same as Example 1.1.

[0035] Example 2.6 A method for manufacturing a novel fire-resistant wire and cable, which differs from Example 1.1 in that: in step S2, the foaming material is melamine, pentaerythritol, ammonium polyphosphate and expanded graphite in a weight ratio of 3:1:1:1.0, and the rest is the same as Example 1.1.

[0036] Example 3.1 A method for manufacturing a novel fire-resistant wire and cable, which differs from Example 1.1 in that: in step S1, benzotriazole and 75wt% ethanol in a weight ratio of 1:100 are also coated on the outside of the conductor, and the coating amount is controlled at 35sccm. After coating, it is dried until there is no liquid on the surface, and the fire-resistant layer is continued to be prepared. The rest is the same as Example 1.1.

[0037] Example 3.2 A method for manufacturing a novel fire-resistant wire and cable, which differs from Example 1.1 in that: in step S1, benzotriazole and 75wt% ethanol in a weight ratio of 1.1:100 are also coated on the outside of the conductor, and the coating amount is controlled at 35sccm. After coating, it is dried until there is no liquid on the surface, and the fire-resistant layer is continued to be prepared. The rest is the same as Example 1.1.

[0038] Example 3.3 A method for manufacturing a novel fire-resistant wire and cable, which differs from Example 1.1 in that: in step S1, benzotriazole and 75wt% ethanol in a weight ratio of 1.2:100 are also coated on the outside of the conductor, and the coating amount is controlled at 35sccm. After coating, it is dried until there is no liquid on the surface, and the fire-resistant layer is continued to be prepared. The rest is the same as Example 1.1.

[0039] Comparative Example 1 The difference from Example 1.1 is that in step S2, the amount of raw materials used for the refractory layer is different, as shown in Table 2, and the rest is the same as Example 1.1.

[0040] Table 2 Amount of raw materials used for the refractory layer of comparative example 1 Group Binder Inorganic refractory filler Additives Foam material Photoinitiator Example 1.1 29 65 22 31 10 Comparative Example 1.1 25 75 15 35 5 Comparative Example 1.2 35 55 30 25 15 Comparative Example 2 The difference from Example 1.1 is that in step S23, no series production is carried out, and after the refractory layer is prepared, the insulating layer is extruded after an interval of 30 minutes, and the rest is the same as Example 1.1.

[0041] Performance Testing 1. Referring to the standard of GB / T 3956-2008, the conductor DC resistance of the cables obtained in the examples and comparative examples at 20°C was measured; 2. Referring to the standard of GB / T 12706.1-2020, the insulation of the cables was measured to be non-breakdown after a certain period of time at an AC voltage of 2.4 kV and 3.5 kV respectively; 3. According to GB / T 12706.1-2020, at a temperature of (200±3)℃ and a mechanical stress of 20N / mm 2 Determine the thermal elongation properties of insulation under a load of, and record the maximum elongation under load and the permanent elongation after cooling; 4. Refer to GB / T 12706.1-2020, perform heat treatment at 130°C for 1h, and record the insulation shrinkage rate; 5. Refer to GB / T 18380.12-2022, measure the vertical combustion performance of a single cable, and record the distance L1 between the lower edge of the upper bracket and the starting point of the carbonized part, and the distance L2 from the burning downward to the lower edge of the upper bracket; 6. According to the standard of GB / T 19216.21-2003, the fire supply temperature shall not be lower than 750℃, the applied voltage shall be 1000V, the fire supply time shall be 180min, and no short circuit (2A fuse shall not be blown) and no conductor shall be blown (indicator light shall not be extinguished) shall be maintained during the test; Table 3.1 Performance test table Group DC resistance Ω / km 2.4kV non-breakdown time / h 3.5kV non-breakdown time / min Example 1.1 4.51 4.0 5.0 Example 1.2 4.51 4.0 5.0 Example 1.3 4.52 4.0 5.0 Example 2.1 4.51 4.0 5.0 Example 2.2 4.52 4.0 5.0 Example 2.3 4.51 4.0 5.0 Example 2.4 4.51 4.0 5.0 Example 2.5 4.52 4.0 5.0 Example 2.6 4.51 4.0 5.0 Comparative Example 1.1 4.52 3.5 5.0 Comparative Example 1.2 4.52 4.0 4.5 Comparative Example 2 4.89 2.5 3.5 Table 3.2 Performance test table Table 3.3 Performance test table Group <![CDATA[L1 / mm]]> <![CDATA[L2 / mm]]> Flame temperature / ℃ Example 1.1 335 440 1000 Example 1.2 330 445 980 Example 1.3 330 450 950 Example 2.1 380 420 1020 Example 2.2 395 410 1040 Example 2.3 395 405 1040 Example 2.4 395 405 1050 Example 2.5 380 415 1010 Example 2.6 340 435 990 Comparative Example 1.1 310 485 850 Comparative Example 1.2 315 485 890 Comparative Example 2 255 520 760 Data Analysis: It can be seen from Table 3 that the conductor DC resistance of the cable obtained in Example 1 of the present application at 20°C is 4.51-4.52Ω / km, the insulation non-breakdown time under 2.4kV AC voltage is 4.0h, and the insulation non-breakdown time under 3.5kV AC voltage is 5.0min, which proves that the cable of the present application has good electrical insulation; at the same time, the cable obtained in Example 1 has good electrical insulation at a temperature of (200±3)°C and a mechanical stress of 20N / mm 2Under a load of , its maximum elongation is only 68-71%, the permanent elongation after cooling is 0%, and the insulation shrinkage after heat treatment at a temperature of 130°C for 1h is only 1%, which proves that the cable of the present application has good heat resistance and thermal stability; finally, in the combustion test of the cable obtained in Example 1, the distance between the lower edge of the upper bracket and the starting point of the carbonized part is 330-335mm, and the distance from the combustion to the lower edge of the upper bracket is 440-445mm. At the same time, under the conditions of a voltage of 1000V and a fire supply time of 180min, the voltage is maintained and the maximum flame temperature that the conductor can withstand without melting is as high as 950-1000°C, which proves that the cable of the present application has excellent fire resistance and flame retardancy.

[0042] In Example 2, the present application changes the components of the foaming material, wherein the various indicators of Examples 2.1-2.5 are better than those of Example 1.1, proving that the present application can form a protective gas and a stable structural layer at high temperature to isolate oxygen by using melamine and pentaerythritol as foaming materials, and can also improve the corrosion resistance and crack resistance of the inorganic refractory filler, making it more stable in high temperature and corrosive environments, and reducing the number of cracks formed in a combustion environment; at the same time, the silane-coated ammonium polyphosphate and expanded graphite are compounded to interact at high temperature to form a dense expansion layer, and decompose to produce flame-retardant substances, thereby reducing the proportion of combustible substances. The multiple substances cooperate with each other to effectively improve the fire resistance and heat insulation capabilities of the foaming material, thereby optimizing the fire resistance and flame retardancy of the cable; The various indicators of Examples 2.2-2.4 are better than those of Examples 2.1 and 2.5, which proves that the present application ensures that the expanded graphite can provide sufficient carbon source during the combustion process by strictly controlling the weight ratio of silane-coated ammonium polyphosphate and expanded graphite, and also ensures that the silane-coated ammonium polyphosphate can achieve the best effect of releasing flame-retardant substances. At this time, the fire resistance and flame retardancy of the cable are at a high level; Example 2.6 of the present application uses a compound of unmodified ammonium polyphosphate and expanded graphite. The various indicators of the obtained cable are not significantly different from those of Example 1.1, proving that the expanded graphite of the present application needs to be used together with silane-coated ammonium polyphosphate to exert a synergistic effect. Simply adding expanded graphite to the foaming material system of Example 1 cannot achieve an effective synergistic effect. The fire resistant and flame retardant indicators of comparative example 1 are significantly inferior to those of example 1.1, which proves that there is a good synergistic effect between the raw materials used for the fire resistant layer of the present application, and the weight ratio of each component controlled by the present application can further enhance the fire resistant and flame retardant effects of the cable; the various indicators of comparative example 2 are inferior to those of example 1.1, which proves that the preparation method of the present application prepares the fire resistant layer and the insulating layer by utilizing a series production method, which not only greatly improves the production efficiency, but also maximizes the uniformity and completeness of the fire resistant layer, thereby improving the stability of the fire resistant and flame retardant properties of the cable.

[0043] The embodiments of this specific implementation method are all preferred embodiments of the present application, and are not intended to limit the protection scope of the present application. Therefore, all equivalent changes made based on the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A new type of fire-resistant wire and cable, characterized in that: The invention comprises a wire core (1), a wrapping layer (2) and a protective layer (3) which are arranged in sequence from the inside to the outside, and also comprises a filler (4) which abuts against the wire core (1) and is arranged inside the wrapping layer (2). The wire core (1) comprises a conductor (11), a fire-resistant layer (12) and an insulating layer (13) which are arranged in sequence from the inside to the outside. The raw materials used for the fire-resistant layer (12) include the following components in parts by weight: 28-30 parts of a binder; 60-70 parts of an inorganic fire-resistant filler; and 20-24 parts of a foaming material. ; 30-32 parts of auxiliary agent; 8-12 parts of photoinitiator, the binder is polyvinyl formal or acrylic resin emulsion, the photoinitiator contains double absorption peaks, the absorption peak 1 ranges from 270-290nm, and the absorption peak 2 ranges from 360-380nm; the raw material used for the insulating layer (13) is any one of polyvinyl chloride, cross-linked polyethylene or polyolefin; the raw material used for the protective layer (3) is any one of polyethylene, flame retardant polyethylene and low-smoke halogen-free flame retardant polyolefin.

2. A new type of fire-resistant wire and cable according to claim 1, characterized in that: The inorganic refractory filler includes mica and nano magnesium oxide.

3. The method for manufacturing a novel fire-resistant wire and cable according to claim 1, characterized in that: The auxiliary agent comprises antimony trioxide, magnesium hydroxide and nano-montmorillonite.

4. A new type of fire-resistant wire and cable according to claim 1, characterized in that: The foaming material comprises melamine, pentaerythritol, silane-coated ammonium polyphosphate and expanded graphite, wherein the weight ratio of the silane-coated ammonium polyphosphate to the expanded graphite is 1:(0.5-1.5).

5. A method for manufacturing the novel fire-resistant wire and cable according to claims 1-4, characterized in that: The following steps are involved: S1, making a conductor (11); S2, preparing a refractory layer (12) outside the conductor (11) obtained in the step S1, then carrying out serial production on the outside of the refractory layer (12), immediately extruding an insulating layer (13) to obtain a wire core (1), wherein the refractory layer (12) is formed by solidifying a refractory mixture, and the preparation method of the refractory mixture comprises the following steps: stirring a binder, an inorganic refractory filler and an auxiliary agent according to weight at a rotation speed of 800-1000 r / min for 5 minutes, then adding a foaming material at a rotation speed of 600-800 r / min at a feeding speed of 5 kg / min, after the addition is completed, mixing the material at a rotation speed of 1200-1400 r / min for 5 minutes, then adding a photoinitiator at a rotation speed of 400-600 r / min at a feeding speed of 5 kg / min, stirring until there is no powder accumulation on the liquid surface, and finally mixing the material at a rotation speed of 1200-1400 r / min for 25 minutes to obtain a refractory mixture; S3, spirally twisting the multiple cores (1) obtained in step S2, and setting a filler (4) in the gap between each core (1), and then setting a sheath (2) between the filler (4) and the outer side of the core (1), ensuring that the cores (1) are circumferentially arranged along the inner wall of the sheath (2) and are in close contact with the inner wall of the sheath (2), and then setting a protective layer (3) on the outer side of the sheath (2), and finally obtaining a new type of fire-resistant wire and cable.

6. The method for manufacturing a novel fire-resistant wire and cable according to claim 5, characterized in that: In the step S1, an antioxidant is also coated on the outside of the conductor (11), wherein the antioxidant comprises benzotriazole and 75 wt% ethanol in a weight ratio of (1-1.2):

100.

7. The method for manufacturing a novel fire-resistant wire and cable according to claim 4, characterized in that: In step S2, the specific steps of preparing the refractory layer (12) are as follows: Preheat the conductor (11) to 87-93°C, heat the refractory mixture for 15-18 seconds and then spray it, with a spraying amount of 100-110 g / m 2 , sprayed on the surface of the conductor (11) for initial shaping, and then photocured to obtain a fire-resistant layer (12), the controlled energy of the photocuring being 800-1000 MJ / cm in the UV band 2 , the light curing line speed is 90-100m / min.

8. The method for manufacturing a novel fire-resistant wire and cable according to claim 4, characterized in that: In step S2, the average thickness of the insulating layer (13) is 0.3-3.0 mm.

9. The method for manufacturing a novel fire-resistant wire and cable according to claim 4, characterized in that: In step S3, the average overlap rate of the wrapping layer (2) is not less than 15%, and the minimum overlap rate is not less than 10%.

10. The method for manufacturing a novel fire-resistant wire and cable according to claim 4, characterized in that: In step S3, the average thickness of the protective layer (3) is 1.4-5.0 mm.

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