A low-temperature porcelain-forming fireproof cable and its production process

Abstract

The present invention relates to the technical field of fireproof cables, and in particular to a low-temperature porcelain-forming fireproof cable and its production process, comprising a plurality of wire cores, the plurality of wire cores are evenly distributed, the plurality of wire cores are extruded with an oxygen-isolating layer outside, the oxygen-isolating layer and the wire core are filled with an expansion filler, the oxygen-isolating layer is wrapped with a flame-retardant tape outside, a sheath layer is arranged outside the flame-retardant tape, the wire core comprises a conductor, a fire-resistant layer and an insulating layer, the fire-resistant layer is wrapped outside the conductor, the insulating layer is extruded outside the fire-resistant layer, and the expansion filler is filled between the insulating layer and the oxygen-isolating layer. The purpose of the present invention is to solve the problems pointed out in the above-mentioned background technology, so that the fireproof cable can be porcelainized at a low temperature when encountering a fire, which is beneficial to the transmission of electricity, and after porcelainization, it will not be broken down due to the peeling of the insulating layer caused by the vibration and impact of disaster relief.

Description

Technical Field

[0001] The invention relates to the technical field of fireproof cables, and in particular to a low-temperature porcelain-forming fireproof cable and a production process thereof. Background Art

[0002] As society's requirements for security and system safety continue to increase, the consumer market has an increasingly strong demand for special cable products with high performance, high efficiency and safety. Mineral fireproof cables have been widely recognized by the market for their excellent fire retardant properties. Rigid mineral insulated cables (BTTZ cables) have superior fire resistance and do not burn or release gas under flame conditions, but it is difficult to produce multi-core cables and long cables with specifications of 50mm2 and above. Moreover, the hardness of rigid mineral insulated cables is higher than that of ordinary cables, and their weight is about twice that of ordinary cables. It is not easy to achieve a parallel and neat effect when laying, and it is difficult to find fault points when the lines are long and there are many joints. Therefore, the construction and maintenance of cables are more difficult. Flexible mineral insulated cables use the processing technology of conventional power cables, which can realize the production of multi-core and large-section cables, avoiding the installation and laying problems of rigid mineral insulated cables.

[0003] Existing flexible mineral insulated cables are generally composed of four parts: conductor, mineral insulation layer, oxygen barrier layer, and sheath. They have the following defects: 1. The gap between the mica tapes in the existing insulation materials is easy to crack when bent, which poses a serious safety hazard; magnesium oxide is very easy to react chemically with moisture in the air and absorbs moisture, which reduces the insulation performance; ceramic polyolefin / silicone rubber materials have high calorific value, poor light transmittance, and weak porcelain strength. 2. The oxygen barrier layer is generally composed of sodium silicate, aluminum hydroxide, and magnesium hydroxide in a certain proportion. It is easy to harden and has certain conductivity and hygroscopicity. During use, the oxygen barrier layer absorbs moisture, resulting in reduced insulation performance, which in turn causes line failures and the inability to transmit power normally. 3. It is difficult for fire resistance to pass the C, W, and Z technical requirements specified in the BS6387 standard. 4. Since the cable partially uses organic insulation and sheath, it cannot meet the B1 level requirements in terms of flame retardancy, smoke density, and heat release performance. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide a low-temperature porcelain-forming fireproof cable and its production process, which is used to solve the problems pointed out in the above background technology, so that the fireproof cable can be porcelain-formed at low temperature when encountering a fire, which is beneficial to the transmission of electricity, and after porcelain-forming, the insulation layer will not be peeled off and punctured due to disaster relief vibration and impact.

[0005] The present invention solves the above technical problems by the following technical means:

[0006] A low-temperature porcelain-forming fireproof cable comprises a plurality of wire cores, the plurality of wire cores are evenly distributed, the plurality of wire cores are extruded with oxygen-isolating layers on the outside, an expansion filler is filled between the oxygen-isolating layers and the wire cores, a flame-retardant tape is wrapped around the oxygen-isolating layers, a sheath layer is arranged outside the flame-retardant tape, the wire core comprises a conductor, a fire-resistant layer and an insulating layer, the fire-resistant layer is wrapped around the outside of the conductor, the insulating layer is extruded outside the fire-resistant layer, and the expansion filler is filled between the insulating layer and the oxygen-isolating layer.

[0007] By wrapping multiple layers of fire-resistant layers around the conductor, the gap between the mica tape wrapping can be prevented from cracking easily when bent. By setting an insulating layer outside the fire-resistant layer, the insulating layer can be porcelainized at low temperature to avoid affecting the transmission of electricity in the event of a fire. By setting an oxygen-isolating layer outside multiple cores, the oxygen-isolating layer can be porcelainized at low temperature, further protecting the entire cable so that the entire cable will not be broken down due to the peeling of the insulation layer caused by disaster relief vibration and impact. By setting an expansion filler between the oxygen-isolating layer and the insulation layer, the expansion filler will expand when the temperature rises, fill the internal space of the cable, fix the position of the insulated core, and play a heat-insulating role at high temperatures, so that the structure of the insulated core is more stable under high temperature conditions, ensuring the reliable electrical performance of the cable.

[0008] Furthermore, the insulating layer and the oxygen-isolating layer are both low-temperature porcelain-forming fireproof materials.

[0009] By making the insulating layer and the oxygen barrier layer of the same material, on the one hand, processing costs are saved, and on the other hand, the cable can be porcelainized again when encountering high temperatures, further ensuring the reliable electrical performance of the cable.

[0010] Furthermore, the low-temperature porcelain-forming fireproof material comprises the following raw materials in parts by weight: 80-100 parts of silicone rubber, 3-5 parts of hydroxy silicone oil, 50-75 parts of inorganic filler, 0.1-1 part of coupling agent, and 1-2 parts of vulcanizing agent.

[0011] Further, the preparation of the low-temperature porcelain-forming fireproof material comprises the following steps:

[0012] S1 pretreatment: put the inorganic filler in a mixer, stir evenly, add the coupling agent, and continue stirring for 10-30 minutes to obtain the pretreated inorganic filler;

[0013] Preparation of S2 fireproof material: Place silicone rubber in a high-speed mixer and stir at 100-115°C for 10-20 minutes. After stirring, add the inorganic filler and hydroxy silicone oil pretreated in step S1, and continue stirring at 120-130°C for 8-15 minutes. After stirring, add the vulcanizer and continue stirring for 5-10 minutes. After stirring, transfer to the extruder and extrude to obtain a low-temperature porcelain fireproof material.

[0014] By using a coupling agent to first modify the surface of the inorganic filler, the inorganic filler and silicone rubber can be more fully cross-linked, avoiding gaps when the fire-proof material is porcelain-formed at low temperature; by adding hydroxy silicone oil to the silicone rubber, the structure between the inorganic filler and the silicone rubber is more reasonable, the processing performance of the silicone rubber is improved, and the storage time of the silicone rubber is extended, so that the low-temperature porcelain-formed fire-proof material can be stored for a longer time and will not harden or absorb moisture during storage.

[0015] Furthermore, the inorganic filler comprises the following raw materials in parts by weight: 10-30 parts of wollastonite powder, 10-20 parts of calcined clay, 5-10 parts of quartz powder, 1-5 parts of glass powder, 4-5 parts of magnesium borate whiskers, 5-10 parts of boron oxide, 15-20 parts of magnesium hydroxide, 1-5 parts of aluminum hydroxide, and 0.1-5 parts of zinc borate.

[0016] Furthermore, the specific steps for preparing the inorganic filler are as follows: calcined clay, wollastonite powder and quartz powder are added to a container according to a mass ratio, stirred evenly, and then a mixture of glass powder, boron oxide and magnesium borate whiskers is added. After stirring evenly, hydroxy silicone oil is added, stirred into a viscous state, transferred into a mold, prepared into granules, transferred into an oven, dried at 80-100° C., after drying, placed in a ball mill, ball milled, after ball milling, the powder is placed in an aluminate coupling agent solution, a mixture of zinc borate, magnesium hydroxide and aluminum hydroxide is added, and the mixture is reacted at 45-60° C. for 12-24 hours. After the reaction is completed, suction is filtered, and the solid is transferred into an oven and dried at 80-100° C. After drying, an inorganic filler is obtained.

[0017] By first mixing calcined clay, wollastonite powder and quartz powder uniformly, then adding boron oxide and magnesium borate whiskers as low-temperature ceramic agents and glass powder as a binder, the two can be quickly sintered into ceramics at 625°C after mixing, and the ceramics will not crack easily, and can effectively resist impact and vibration, thereby ensuring the electrical performance of the cable. Then, the mixed materials are prepared into granules, ground by ball milling, and the surface of the powder is modified by an aluminate coupling agent, and then zinc borate, magnesium hydroxide and aluminum hydroxide are cross-linked on the surface of the powder, so that zinc borate, magnesium hydroxide and aluminum hydroxide are cross-linked on the surface of the low-temperature ceramic as flame retardants, thereby enhancing the flame retardant performance, and at the same time, it will not affect the low-temperature ceramic performance.

[0018] Furthermore, the expansion filler is a high temperature resistant inorganic silicon expansion filler.

[0019] High temperature resistant inorganic silicon expansion material, on the one hand, fixes the position of the insulating core when expanding at high temperature, and on the other hand, can also play a heat insulation role at high temperature, so that the structure of the insulating core is more stable under high temperature conditions, ensuring the reliable electrical performance of the cable.

[0020] Furthermore, the fire-resistant layer is formed by wrapping mica tape, the number of wrapping layers is greater than three, and the thickness of the fire-resistant layer is greater than 0.4 mm.

[0021] Through multi-layer wrapping, the wrapping gap of a single-layer mica tape can be prevented from cracking easily when bent.

[0022] Furthermore, the silicone rubber is silicone rubber NE9240, the coupling agent is a silane coupling agent, and the vulcanizing agent is a dipentadienyl vulcanizing agent.

[0023] The present invention also discloses a production process of a low-temperature porcelain-formed fireproof cable, comprising the low-temperature porcelain-formed fireproof cable described in the above claims, and further comprising the following steps: conductor wire drawing, annealing, twisting, fire-resistant wrapping, insulation extrusion, wire core cabling, extruding oxygen insulation layer, wrapping flame-retardant tape, and extruding sheath.

[0024] Beneficial effects of the present invention:

[0025] 1. The insulation layer and oxygen barrier layer can be quickly formed into porcelain under high temperature or flame of about 625℃, and the porcelain forming time is ≤5 minutes, which effectively prevents the flame and temperature from further conducting inward, thereby ensuring the integrity of the line; and the cable has good fire resistance, fire isolation, water isolation and earthquake resistance. Under the flame of 950℃, the line can maintain stable operation for 180 minutes, and the power supply and information can still be transmitted normally;

[0026] 2. The hardening time of the insulation layer and oxygen barrier layer materials is ≥100 days, which is convenient for storage, transportation and installation;

[0027] 3. The cable insulation uses low-temperature fast-ceramic inorganic fireproof materials, which can withstand higher flame temperatures; high-temperature resistant inorganic silicon expansion fillers are used to fill the cable core gaps. The filling layer expands as the temperature rises after the cable burns, making the cable structure more stable after high-temperature combustion, and will not cause insulation peeling and breakdown due to disaster relief vibration and impact;

[0028] 4. Use low-smoke halogen-free flame-retardant sheath materials with excellent oxygen index, smoke density, crusting performance and other parameters. The combustion performance should meet the B1 performance requirements specified in the GB 31247-2014 "Classification of Combustion Performance of Cables and Optical Cables" standard. It can meet the use requirements of high-rise buildings, entertainment venues, hospitals, airports, shopping malls and many construction projects that require high quality and high safety in large cities, control lines of fire equipment in fire protection systems, and signal transmission lines of fire alarm systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a structural schematic diagram of a low-temperature porcelain-forming fireproof cable of the present invention;

[0030] Figure 2 This is a process flow chart of a low-temperature porcelain-forming fireproof cable of the present invention;

[0031] Among them, there are a conductor 1, a fire-resistant layer 11, an insulating layer 12, an expansion filler 2, an oxygen barrier layer 3, a flame-retardant tape 4, and a sheath layer 5. DETAILED DESCRIPTION

[0032] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments:

[0033] Example 1, Preparation of low temperature porcelain fireproof cable

[0034] Preparation of inorganic fillers:

[0035] 10 parts by mass of calcined clay, 10 parts by mass of 3000 mesh wollastonite powder and 5 parts by mass of quartz powder are added to a container, stirred evenly, and then 1 part by mass of 2000 mesh glass powder, 5 parts by mass of boron oxide and 4 parts by mass of magnesium borate whiskers are added, stirred evenly, 3.5 parts by mass of hydroxy silicone oil are added, stirred into a viscous state, transferred into a mold, prepared into granular form, transferred into an oven, dried at 100° C., after drying, placed in a ball mill, ball-milled into powder, after ball milling, the powder is placed in a sufficient amount of aluminate coupling agent solution, 0.1 parts by mass of zinc borate, 15 parts by mass of magnesium hydroxide and 1 part by mass of aluminum hydroxide are added, reacted at 45° C. for 24 hours, after the reaction is completed, filtered, the solid is transferred into an oven, dried at 100° C., and after drying, an inorganic filler is obtained;

[0036] Preparation of low temperature porcelain fireproof materials:

[0037] S1 pretreatment: 50 parts by weight of inorganic filler is placed in a mixer, stirred evenly, and then 0.1 parts by weight of silane coupling agent is added, and stirring is continued for 10 minutes to obtain a pretreated inorganic filler;

[0038] Preparation of S2 fireproof material: 80 parts by weight of silicone rubber NE9240 was placed in a high-speed mixer and stirred at 100°C for 10 minutes. After stirring, the inorganic filler pretreated in step S1 and 3 parts by weight of hydroxy silicone oil were added and stirred at 120°C for 8 minutes. After stirring, 1 part by weight of dipentadienyl vulcanizer was added and stirred for 5 minutes. After stirring, the mixture was transferred to an extruder and extruded to obtain a low-temperature porcelain fireproof material.

[0039] Processing technology of low temperature porcelain fireproof cable:

[0040] The copper rod conductor 1 is drawn by a wire drawing machine, and the conductor 1 after drawing is annealed by a quenching machine. After annealing, the multi-strand conductor 1 is twisted and compacted by a stranding machine, and then the stranded wire is wrapped with a fire-resistant layer 11 by a wrapping machine. In the wrapping process, mica tape is used for wrapping. When wrapping with mica tape, the number of wrapping layers is greater than 3 layers, and the wrapping thickness is greater than 0.4mm, so as to avoid the fire-resistant layer 11 from cracking when the cable is bent; the stranded wire wrapped with mica tape is passed through an extruder. In this process, the low-temperature porcelain fireproof material is transferred to the extruder during the preparation process instead of being transferred to the extruder. Through the operation of the extruder, the low-temperature porcelain fireproof material is extruded as an insulating layer 12 on the mica tape wrapping layer, and then cooled and formed. , and obtain a core; multiple strands of cores are formed into a cable, and the cable passes through an extruder. At this time, a low-temperature porcelain fireproof material is extruded on multiple cores as an oxygen barrier layer 3. After the extrusion is completed, the high-temperature resistant inorganic silicon expansion filler 2 is densely filled between the insulating layer 12 and the oxygen barrier layer 3, and then the flame retardant tape 4 is wrapped on the oxygen barrier layer 3 by a wrapping machine. The flame retardant tape 4 is a ceramic fiber cloth, and the wrapping overlap rate of the ceramic fiber cloth is greater than 93%. Then, the cable wrapped with the ceramic fiber cloth passes through an extruder, and the extruder extrudes a polyolefin low-smoke halogen-free flame-retardant plastic on the surface of the ceramic fiber cloth to form a sheath layer 5. Then, by printing on the sheath layer 5, a withstand voltage test, a finished product inspection and warehousing, a low-temperature porcelain fireproof cable is obtained.

[0041] Example 2, Preparation of Low-Temperature Porcelain Fireproof Cable

[0042] Preparation of inorganic fillers:

[0043] 15 parts by mass of calcined clay, 20 parts by mass of 3000 mesh wollastonite powder and 7.5 parts by mass of quartz powder are added to a container, stirred evenly, and then 2 parts by mass of 2000 mesh glass powder, 6 parts by mass of boron oxide and 4.5 parts by mass of magnesium borate whiskers are added, stirred evenly, 7.3 parts by mass of hydroxy silicone oil are added, stirred into a viscous state, transferred into a mold, prepared into granular form, transferred into an oven, dried at 90° C., after drying, placed in a ball mill, ball-milled into powder, after ball milling, the powder is placed in a sufficient amount of aluminate coupling agent solution, 0.5 parts by mass of zinc borate, 18 parts by mass of magnesium hydroxide and 2 parts by mass of aluminum hydroxide are added, reacted at 50° C. for 16 hours, after the reaction is completed, filtered, the solid is transferred into an oven, dried at 90° C., and after drying, an inorganic filler is obtained;

[0044] Preparation of low temperature porcelain fireproof materials:

[0045] S1 pretreatment: 60 parts by weight of inorganic filler are placed in a mixer, stirred evenly, and then 0.5 parts by weight of silane coupling agent is added, and stirring is continued for 20 minutes to obtain a pretreated inorganic filler;

[0046] Preparation of S2 fireproof material: 90 parts by weight of silicone rubber NE9240 was placed in a high-speed mixer and stirred at 110°C for 15 minutes. After stirring, the inorganic filler pretreated in step S1 and 3.8 parts by weight of hydroxy silicone oil were added and stirred at 125°C for 11 minutes. After stirring, 1.2 parts by weight of dipentadienyl vulcanizer was added and stirred for 7.5 minutes. After stirring, the mixture was transferred to an extruder and extruded to obtain a low-temperature porcelain fireproof material.

[0047] Processing technology of low temperature porcelain fireproof cable:

[0048] The copper rod conductor 1 is drawn by a wire drawing machine, and the conductor 1 after drawing is annealed by a quenching machine. After annealing, the multi-strand conductor 1 is twisted and compacted by a stranding machine, and then the stranded wire is wrapped with a fire-resistant layer 11 by a wrapping machine. In the wrapping process, mica tape is used for wrapping. When wrapping with mica tape, the number of wrapping layers is greater than 3 layers, and the wrapping thickness is greater than 0.4mm, so as to avoid the fire-resistant layer 11 from cracking when the cable is bent; the stranded wire wrapped with mica tape is passed through an extruder. In this process, the low-temperature porcelain fireproof material is transferred to the extruder during the preparation process instead of being transferred to the extruder. Through the operation of the extruder, the low-temperature porcelain fireproof material is extruded as an insulating layer 12 on the mica tape wrapping layer, and then cooled and formed. , and obtain a core; multiple strands of cores are formed into a cable, and the cable passes through an extruder. At this time, a low-temperature porcelain fireproof material is extruded on multiple cores as an oxygen barrier layer 3. After the extrusion is completed, the high-temperature resistant inorganic silicon expansion filler 2 is densely filled between the insulating layer 12 and the oxygen barrier layer 3, and then the flame retardant tape 4 is wrapped on the oxygen barrier layer 3 by a wrapping machine. The flame retardant tape 4 is a ceramic fiber cloth, and the wrapping overlap rate of the ceramic fiber cloth is greater than 93%. Then, the cable wrapped with the ceramic fiber cloth passes through an extruder, and the extruder extrudes a polyolefin low-smoke halogen-free flame-retardant plastic on the surface of the ceramic fiber cloth to form a sheath layer 5. Then, by printing on the sheath layer 5, a withstand voltage test, a finished product inspection and warehousing, a low-temperature porcelain fireproof cable is obtained.

[0049] Example 3, Preparation of low temperature porcelain fireproof cable

[0050] Preparation of inorganic fillers:

[0051] 20 parts by mass of calcined clay, 30 parts by mass of 3000 mesh wollastonite powder and 10 parts by mass of quartz powder are added to a container, stirred evenly, and then 5 parts by mass of 2000 mesh glass powder, 10 parts by mass of boron oxide and 5 parts by mass of magnesium borate whiskers are added, stirred evenly, 10 parts by mass of hydroxy silicone oil are added, stirred into a viscous state, transferred into a mold, prepared into granular form, transferred into an oven, dried at 80° C., after drying, placed in a ball mill, ball-milled into powder, after ball milling, the powder is placed in a sufficient amount of aluminate coupling agent solution, 5 parts by mass of zinc borate, 20 parts by mass of magnesium hydroxide and 5 parts by mass of aluminum hydroxide are added, reacted at 60° C. for 12 hours, after the reaction is completed, filtered, the solid is transferred into an oven, dried at 80° C., and after drying, an inorganic filler is obtained;

[0052] Preparation of low temperature porcelain fireproof materials:

[0053] S1 pretreatment: 70 parts by weight of inorganic filler are placed in a mixer, stirred evenly, and then 1 part by weight of silane coupling agent is added, and stirring is continued for 30 minutes to obtain a pretreated inorganic filler;

[0054] Preparation of S2 fireproof material: 100 parts by weight of silicone rubber NE9240 was placed in a high-speed mixer and stirred at 115°C for 20 minutes. After stirring, the inorganic filler pretreated in step S1 and 5 parts by weight of hydroxy silicone oil were added and stirred at 130°C for 15 minutes. After stirring, 2 parts by weight of dipentadienyl vulcanizer were added and stirred for 10 minutes. After stirring, the mixture was transferred to an extruder and extruded to obtain a low-temperature porcelain fireproof material.

[0055] Processing technology of low temperature porcelain fireproof cable:

[0056] The copper rod conductor 1 is drawn by a wire drawing machine, and the conductor 1 after drawing is annealed by a quenching machine. After annealing, the multi-strand conductor 1 is twisted and compacted by a stranding machine, and then the stranded wire is wrapped with a fire-resistant layer 11 by a wrapping machine. In the wrapping process, mica tape is used for wrapping. When wrapping with mica tape, the number of wrapping layers is greater than 3 layers, and the wrapping thickness is greater than 0.4mm, so as to avoid the fire-resistant layer 11 from cracking when the cable is bent; the stranded wire wrapped with mica tape is passed through an extruder. In this process, the low-temperature porcelain fireproof material is transferred to the extruder during the preparation process instead of being transferred to the extruder. Through the operation of the extruder, the low-temperature porcelain fireproof material is extruded as an insulating layer 12 on the mica tape wrapping layer, and then cooled and formed. , and obtain a core; multiple strands of cores are formed into a cable, and the cable passes through an extruder. At this time, a low-temperature porcelain fireproof material is extruded on multiple cores as an oxygen barrier layer 3. After the extrusion is completed, the high-temperature resistant inorganic silicon expansion filler 2 is densely filled between the insulating layer 12 and the oxygen barrier layer 3, and then the flame retardant tape 4 is wrapped on the oxygen barrier layer 3 by a wrapping machine. The flame retardant tape 4 is a ceramic fiber cloth, and the wrapping overlap rate of the ceramic fiber cloth is greater than 93%. Then, the cable wrapped with the ceramic fiber cloth passes through an extruder, and the extruder extrudes a polyolefin low-smoke halogen-free flame-retardant plastic on the surface of the ceramic fiber cloth to form a sheath layer 5. Then, by printing on the sheath layer 5, a withstand voltage test, a finished product inspection and warehousing, a low-temperature porcelain fireproof cable is obtained.

[0057] Example 4 (Comparative Example 1), Preparation of Low-Temperature Porcelain Fireproof Cable

[0058] Preparation of low temperature porcelain fireproof materials:

[0059] S1 pretreatment: 20 parts by mass of calcined clay, 30 parts by mass of 3000 mesh wollastonite powder, 10 parts by mass of quartz powder, 5 parts by mass of 2000 mesh glass powder, 10 parts by mass of boron oxide, 5 parts by mass of magnesium borate whisker, 0.5 parts by mass of zinc borate, 18 parts by mass of magnesium hydroxide and 2 parts by mass of aluminum hydroxide are placed in a mixer, stirred evenly, then 0.5 parts by mass of silane coupling agent is added, and stirring is continued for 30 minutes to obtain a pretreated inorganic filler;

[0060] Preparation of S2 fireproof material: 90 parts by weight of silicone rubber NE9240 was placed in a high-speed mixer and stirred at 110°C for 20 minutes. After stirring, the inorganic filler pretreated in step S1 and 3.8 parts by weight of hydroxy silicone oil were added and stirred at 125°C for 15 minutes. After stirring, 1.2 parts by weight of dipentadienyl vulcanizer was added and stirred for 10 minutes. After stirring, the mixture was transferred to an extruder and extruded to obtain a low-temperature porcelain fireproof material.

[0061] Processing technology of low temperature porcelain fireproof cable:

[0062] The copper rod conductor 1 is drawn by a wire drawing machine, and the conductor 1 after drawing is annealed by a quenching machine. After annealing, the multi-strand conductor 1 is twisted and compacted by a stranding machine, and then the stranded wire is wrapped with a fire-resistant layer 11 by a wrapping machine. In the wrapping process, mica tape is used for wrapping. When wrapping with mica tape, the number of wrapping layers is greater than 3 layers, and the wrapping thickness is greater than 0.4mm, so as to avoid the fire-resistant layer 11 from cracking when the cable is bent; the stranded wire wrapped with mica tape is passed through an extruder. In this process, the low-temperature porcelain fireproof material is transferred to the extruder during the preparation process instead of being transferred to the extruder. Through the operation of the extruder, the low-temperature porcelain fireproof material is extruded as an insulating layer 12 on the mica tape wrapping layer, and then cooled and formed. , and obtain a core; multiple strands of cores are formed into a cable, and the cable passes through an extruder. At this time, a low-temperature porcelain fireproof material is extruded on multiple cores as an oxygen barrier layer 3. After the extrusion is completed, the high-temperature resistant inorganic silicon expansion filler 2 is densely filled between the insulating layer 12 and the oxygen barrier layer 3, and then the flame retardant tape 4 is wrapped on the oxygen barrier layer 3 by a wrapping machine. The flame retardant tape 4 is a ceramic fiber cloth, and the wrapping overlap rate of the ceramic fiber cloth is greater than 93%. Then, the cable wrapped with the ceramic fiber cloth passes through an extruder, and the extruder extrudes a polyolefin low-smoke halogen-free flame-retardant plastic on the surface of the ceramic fiber cloth to form a sheath layer 5. Then, by printing on the sheath layer 5, a withstand voltage test, a finished product inspection and warehousing, a low-temperature porcelain fireproof cable is obtained.

[0063] Example 5 (Comparative Example 2), Preparation of Low-Temperature Porcelain Fireproof Cable

[0064] Preparation of low temperature porcelain fireproof materials:

[0065] Preparation of fireproof material: 90 parts by weight of silicone rubber NE9240 is placed in a high-speed mixer, stirred at 100°C for 10 minutes, after stirring, 20 parts by weight of calcined clay, 30 parts by weight of 3000-mesh wollastonite powder, 10 parts by weight of quartz powder, 5 parts by weight of 2000-mesh glass powder, 10 parts by weight of boron oxide, 5 parts by weight of magnesium borate whisker, 0.5 parts by weight of zinc borate, 18 parts by weight of magnesium hydroxide, 2 parts by weight of aluminum hydroxide and 3.8 parts by weight of hydroxy silicone oil are added, and stirring is continued for 15 minutes at 125°C. After stirring, 1.2 parts by weight of dipentadienyl vulcanizer is added, and stirring is continued for 10 minutes. After stirring, the mixture is transferred to an extruder and extruded to obtain a low-temperature porcelain fireproof material;

[0066] Processing technology of low temperature porcelain fireproof cable:

[0067] The copper rod conductor 1 is drawn by a wire drawing machine, and the conductor 1 after drawing is annealed by a quenching machine. After annealing, the multi-strand conductor 1 is twisted and compacted by a stranding machine, and then the stranded wire is wrapped with a fire-resistant layer 11 by a wrapping machine. In the wrapping process, mica tape is used for wrapping. When wrapping with mica tape, the number of wrapping layers is greater than 3 layers, and the wrapping thickness is greater than 0.4mm, so as to avoid the fire-resistant layer 11 from cracking when the cable is bent; the stranded wire wrapped with mica tape is passed through an extruder. In this process, the low-temperature porcelain fireproof material is transferred to the extruder during the preparation process instead of being transferred to the extruder. Through the operation of the extruder, the low-temperature porcelain fireproof material is extruded as an insulating layer 12 on the mica tape wrapping layer, and then cooled and formed. , and obtain a core; multiple strands of cores are formed into a cable, and the cable passes through an extruder. At this time, a low-temperature porcelain fireproof material is extruded on multiple cores as an oxygen barrier layer 3. After the extrusion is completed, the high-temperature resistant inorganic silicon expansion filler 2 is densely filled between the insulating layer 12 and the oxygen barrier layer 3, and then the flame retardant tape 4 is wrapped on the oxygen barrier layer 3 by a wrapping machine. The flame retardant tape 4 is a ceramic fiber cloth, and the wrapping overlap rate of the ceramic fiber cloth is greater than 93%. Then, the cable wrapped with the ceramic fiber cloth passes through an extruder, and the extruder extrudes a polyolefin low-smoke halogen-free flame-retardant plastic on the surface of the ceramic fiber cloth to form a sheath layer 5. Then, by printing on the sheath layer 5, a withstand voltage test, a finished product inspection and warehousing, a low-temperature porcelain fireproof cable is obtained.

[0068] By extruding the low-temperature porcelain-forming materials in Examples 1-5 onto the conductor and conducting a spark test, the extruded thickness of the insulating layer was measured to be 2.8 mm, 2.8 mm, 2.8 mm, 2.8 mm, and 2.8 mm, respectively. The test was conducted in accordance with the national standard GB / T3048.9-2007. The test results are shown in Table 1:

[0069]

[0070] The fireproof cables prepared in Examples 1-5 were subjected to a withstand voltage test, and the test results are shown in Table 2 below:

[0071] Example 1 Example 2 Example 3 Example 4 Example 5 25kv Not penetrated Not penetrated Not penetrated Not penetrated Not penetrated 38kv Not penetrated Not penetrated Not penetrated Not penetrated 1 breakdown

[0072] It can be seen from the data in Table 1 and Table 2 that the fire-proof cables prepared in Examples 1-5 have good spark resistance and voltage resistance. In Example 5, there was a breakdown during the 38kv voltage resistance test, indicating that in this solution, the voltage resistance of the cable can be effectively enhanced by first treating the inorganic filler.

[0073] The fireproof cables prepared in Examples 1-5 were tested for porcelain-forming properties and post-sintering seismic properties. The test results are shown in Tables 3 and 4 below:

[0074]

[0075]

[0076] It can be seen from the test results in Table 3 and Table 4 that in this scheme, after the inorganic filler is treated, the oxygen barrier layer of the fire-proof cable can be completely ceramicized at about 625°C, which can effectively ensure the electrical reliability of the cable. At about 950°C, the oxygen barrier layer and the insulating layer are both ceramicized. At this time, the cable can run stably for 180 minutes, and the power supply and information can still be transmitted normally.

[0077] The fireproof cables prepared in Examples 1-5 were tested for storage time under dry conditions at room temperature, and the hardening of the insulating layer and the oxygen barrier layer was tested by changing the depth of the insertion of the pin. The test results are shown in Table 6 below:

[0078] 7d 30d 60d 100d 120d Example 1 2.5cm 2.45cm 2.40cm 2.30cm 1.8cm Example 2 2.5cm 2.40cm 2.40cm 2.35cm 1.95cm Example 3 2.5cm 2.45cm 2.40cm 2.30cm 1.8m Example 4 2.5cm 2.20cm 2.05cm 1.85cm 1.45cm Example 5 2.5cm 2.10cm 1.85cm 1.40cm 1.10cm

[0079] It can be seen from the data in Table 6 that after 100 days of storage, the insertion depth of Examples 1-3 can still reach 2.3 cm or more, indicating that the pin can be inserted into the insulating layer. This further shows that in this solution, the storage time of the cable can be extended by treating the inorganic filler, making the cable easier to store, transport and install.

[0080] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions of the present invention, which should be included in the scope of the claims of the present invention. The techniques, shapes, and structural parts not described in detail in the present invention are all known technologies.

Claims

1. A low-temperature porcelain-forming fireproof cable, characterized in that: The invention comprises a plurality of wire cores, wherein the plurality of wire cores are evenly distributed, an oxygen-isolating layer is extruded outside the plurality of wire cores, an expansion filler is filled between the oxygen-isolating layer and the wire core, the expansion filler is a high-temperature resistant inorganic silicon expansion filler, a flame-retardant tape is wrapped outside the oxygen-isolating layer, a sheath layer is arranged outside the flame-retardant tape, the wire core comprises a conductor, a fire-resistant layer and an insulating layer, the fire-resistant layer is wrapped outside the conductor, the number of the wrapping layers is greater than three, the insulating layer is extruded outside the fire-resistant layer, and the expansion filler is filled between the insulating layer and the oxygen-isolating layer; The insulating layer and the oxygen-isolating layer are both low-temperature porcelain-forming fireproof materials; The oxygen-isolating layer can be completely formed into porcelain at a high temperature of 625°C or under flame; The low-temperature porcelain-forming fireproof material comprises the following raw materials in parts by weight: 80-100 parts of silicone rubber, 3-5 parts of hydroxy silicone oil, 50-75 parts of inorganic filler, 0.1-1 parts of coupling agent, and 1-2 parts of vulcanizing agent; The preparation of the low-temperature porcelain-forming fireproof material comprises the following steps: S1 pretreatment: put the inorganic filler in a mixer, stir evenly, add the coupling agent, and continue stirring for 10-30 minutes to obtain the pretreated inorganic filler; Preparation of S2 fireproof material: Place silicone rubber in a high-speed mixer, stir at 100-115°C for 10-20 minutes, add inorganic filler and hydroxy silicone oil pretreated in step S1, continue stirring at 120-130°C for 8-15 minutes, add vulcanizing agent, continue stirring for 5-10 minutes, transfer to an extruder, extrude, and obtain a low-temperature porcelain fireproof material; The specific steps of preparing the inorganic filler are as follows: 10-20 parts of calcined clay, 10-30 parts of wollastonite powder and 5-10 parts of quartz powder are added to a container according to mass parts, stirred evenly, and then 1-5 parts of a mixture of glass powder, 5-10 parts of boron oxide and 4-5 parts of magnesium borate whiskers are added, stirred evenly, and then hydroxy silicone oil is added, stirred into a viscous state, transferred into a mold, prepared into granules, transferred into an oven, dried at 80-100° C., after drying, placed in a ball mill, ball milled, after ball milling, the powder is placed in a sufficient amount of aluminate coupling agent solution, 0.1-5 parts of zinc borate, 15-20 parts of magnesium hydroxide and 1-5 parts of aluminum hydroxide are added, reacted at 45-60° C. for 12-24 hours, after the reaction is completed, filtered, the solid is transferred into an oven, dried at 80-100° C., and the inorganic filler is obtained after drying.

2. A low-temperature porcelain-forming fireproof cable according to claim 1, characterized in that: The sheath layer is a low-smoke, halogen-free, flame-retardant sheath.

3. A low temperature porcelain fireproof cable according to claim 1, characterized in that: The fire-resistant layer is formed by wrapping a mica tape, and the thickness of the fire-resistant layer is greater than 0.4 mm.

4. A low temperature porcelain fireproof cable according to claim 1, characterized in that: The silicone rubber is silicone rubber NE9240, the coupling agent in the S1 pretreatment step is a silane coupling agent, and the vulcanizing agent is a dipentadienyl vulcanizing agent.

5. A production process for low-temperature porcelain-forming fireproof cables, characterized in that: The preparation of the low-temperature porcelain-forming fireproof cable according to any one of claims 1 to 4 comprises the following steps: conductor drawing, annealing, twisting, fire-resistant wrapping, insulation extrusion, core cabling, extruding oxygen insulation layer, wrapping flame-retardant tape, and extruding sheath.

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