A polyvinyl chloride control cable

Abstract

This invention discloses a polyvinyl chloride (PVC) control cable, comprising, from the inside out, a composite cable core, a water-blocking wrapping tape layer, an insulating inner sheath, a flame-retardant wrapping tape layer, a flame-retardant inner sheath, a metal sheath layer, and an outer sheath. The flame-retardant wrapping tape layer is a ceramicized silicone rubber tape wrapped around the insulating inner sheath. The flame-retardant inner sheath is a flame-retardant silicone rubber material extruded and covered over the water-blocking wrapping tape layer. This product employs a combination of flame-retardant wrapping tape layer and flame-retardant inner sheath technology, with the flame-retardant inner sheath being a flame-retardant silicone rubber material extruded and covered over the water-blocking wrapping tape layer. This material is halogen-free, produces low smoke during combustion, and has excellent flame-retardant properties, providing dual flame-retardant protection. The ceramicized silicone rubber tape forms a hard, ceramic-like protective layer at high temperatures, and combined with the flame-retardant silicone rubber, it provides excellent flame-retardant and heat-insulating effects.

Description

Technical Field

[0001] This invention relates to the field of power cable technology, and more specifically to a polyvinyl chloride control cable. Background Technology

[0002] Control cables are PVC insulated and PVC sheathed control cables suitable for use in industrial and mining enterprises, energy and transportation sectors, and for control and protection circuits with AC rated voltages below 450 / 750 volts. Control cables are moisture-proof, corrosion-proof, and damage-resistant, and can be laid in tunnels or cable trenches. Power cables are used in the main lines of power systems to transmit and distribute high-power electrical energy, while control cables directly transmit electrical energy from the distribution points of the power system to the power connection lines of various electrical equipment and appliances. Power cables generally have a rated voltage of 0.6 / 1kV and above, while control cables are mainly 450 / 750V. During production, power cables have thicker insulation and sheaths than control cables of the same specifications.

[0003] Chinese invention patent CN214847867U discloses a polyvinyl chloride control cable, comprising a composite cable core, a wrapping tape layer, an inner sheath, a metal braided layer, and a wear-resistant outer layer arranged sequentially from the inside out; the wrapping tape layer is ceramicized silicone rubber wrapping tape wrapped around the composite cable core; the wear-resistant outer layer is nylon material extruded and covered on the metal braided layer.

[0004] However, the existing cables have only average flame-retardant properties, which are insufficient to meet the requirements for fire resistance and flame retardancy. To adapt to the rapidly developing market situation of subway construction and to provide safe and reliable fire-resistant cables for subway projects, there is an urgent need for in-depth research and innovative improvements to cable materials and structures. Summary of the Invention

[0005] To overcome the above-mentioned technical defects, the present invention provides a polyvinyl chloride control cable.

[0006] To solve the above problems, the present invention is implemented according to the following technical solution:

[0007] The polyvinyl chloride control cable of the present invention is characterized in that it comprises, from the inside out, a composite cable core, a water-blocking wrapping tape layer, an insulating inner sheath, a flame-retardant wrapping tape layer, a flame-retardant inner sheath, a metal sheath layer, and an outer sheath.

[0008] The flame-retardant wrapping tape layer is a ceramicized silicone rubber tape wrapped around the insulating inner sheath;

[0009] The flame-retardant inner sheath is made of flame-retardant silicone rubber material extruded and covered on a water-blocking wrapping tape layer.

[0010] Preferably, the flame-retardant silicone rubber material comprises the following components in parts by weight:

[0011] 90 parts of polymethylvinylsiloxane;

[0012] 56 parts of silicon dioxide;

[0013] 6 parts of hydroxysiloxane;

[0014] 10 parts calcium silicate;

[0015] 16 parts of composite flame retardant;

[0016] One part of hydrosiloxane;

[0017] One part of platinum vulcanizing agent.

[0018] Preferably, the composite flame retardant is a mixture of inorganic hydroxide, antimony trioxide, and magnesium aluminum carbonate hydrotalcite, wherein the mass ratio of the inorganic hydroxide, antimony trioxide, and magnesium aluminum carbonate hydrotalcite is 5:1:3.

[0019] Preferably, the insulating inner sheath is made of ceramicized silicone rubber material extruded and covered on a water-blocking wrapping tape layer.

[0020] Preferably, the ceramicized silicone rubber material comprises the following components in parts by weight:

[0021] 80 parts of α,ω-terminated hydroxyl polydimethylsiloxane;

[0022] 40 parts of fumed silica;

[0023] 20 parts of modified nano-ceramic clay;

[0024] 6 parts of 500 viscosity silicone oil;

[0025] 10 parts of composite flame retardant;

[0026] 20 parts of vitrifying powder;

[0027] 1 part of crosslinking aid;

[0028] One part of platinum vulcanizing agent.

[0029] Preferably, the modified nano-ceramic is prepared by the following method:

[0030] (1) Raw material mixing: Nano-clay is mixed with aminopropyltriethoxysilane to obtain a mixture; wherein, the amount of aminopropyltriethoxysilane is 3-5% of the mass of nano-clay;

[0031] (2) Heating and stirring: Heat the mixture to 50-60°C and stir continuously for 20-30 minutes;

[0032] (3) Add nano silica: Add 1.5% of the total mass of nano silica to the heated and stirred mixture;

[0033] (4) High-speed dispersion: The mixture with added nano-silica is subjected to high-speed dispersion treatment to obtain modified nano-ceramic.

[0034] Preferably, the metal sheath layer is a corrugated aluminum sheath.

[0035] Preferably, the composite cable core includes a plurality of insulated cores, each insulated core including a conductor and an insulating layer covering the outer surface of the conductor;

[0036] The insulating layer is a polyvinyl chloride sheath material extruded onto the conductor.

[0037] Preferably, the conductor is the first conductor structure or the second conductor structure in GB / T 3956.

[0038] Compared with the prior art, the beneficial effects of the present invention are:

[0039] This invention provides a polyvinyl chloride (PVC) control cable, comprising, from the inside out, a composite cable core, a water-blocking wrapping tape layer, an insulating inner sheath, a flame-retardant wrapping tape layer, a flame-retardant inner sheath, a metal sheath layer, and an outer sheath. The flame-retardant wrapping tape layer is a ceramicized silicone rubber tape wrapped around the insulating inner sheath. The flame-retardant inner sheath is a flame-retardant silicone rubber material extruded and covering the water-blocking wrapping tape layer.

[0040] 1. The cable of this product is equipped with a ceramicized silicone rubber wrapping layer, which has excellent flame retardant properties and low heat generation during combustion. The ceramicized material used forms a hard protective layer at high temperatures above 350℃, with honeycomb-like pores inside, which can play a good role in heat insulation. At the same time, the material has good shelling performance during heating, does not drip, and has good low smoke performance.

[0041] 2. This product employs a combination of flame-retardant wrapping tape and a flame-retardant inner sheath. The flame-retardant inner sheath consists of flame-retardant silicone rubber extruded over the water-blocking wrapping tape. This material is halogen-free, produces low smoke during combustion, and exhibits excellent flame-retardant properties, providing dual flame-retardant protection. The ceramicized silicone rubber tape forms a hard, ceramic-like protective layer at high temperatures, which, combined with the flame-retardant silicone rubber, provides excellent flame-retardant and heat-insulating performance. This combined structural design allows the cable to remain undamaged for a longer period in the event of a fire, delaying the spread of fire and protecting the internal structure of the cable. Attached Figure Description

[0042] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings, wherein:

[0043] Figure 1 This is a cross-sectional schematic diagram of a polyvinyl chloride control cable according to the present invention;

[0044] In the picture:

[0045] 10-Conductor;

[0046] 20 - Insulation layer;

[0047] 30 - Water-blocking wrapping tape layer;

[0048] 40 - Insulating inner sheath;

[0049] 50 - Flame-retardant wrapping tape layer;

[0050] 60-Flame-retardant inner sheath;

[0051] 70 - Metal sheath layer;

[0052] 80 - Outer sheath. Detailed Implementation

[0053] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0054] Existing cables have only average flame-retardant properties, which are insufficient to meet the requirements for fire resistance and flame retardancy. To adapt to the rapidly developing market situation of subway construction and to provide safe and reliable fire-resistant cables for subway projects, there is an urgent need for in-depth research and innovative improvements to cable materials and structures.

[0055] Therefore, the present invention provides a polyvinyl chloride control cable for subway systems. For example... Figure 1 As shown, this invention discloses a preferred structure for a polyvinyl chloride control cable.

[0056] Example 1

[0057] like Figure 1 As shown, the polyvinyl chloride control cable of the present invention comprises, from the inside out, a composite cable core, a water-blocking wrapping tape layer, an insulating inner sheath, a flame-retardant wrapping tape layer, a flame-retardant inner sheath, a metal sheath layer, and an outer sheath. The flame-retardant wrapping tape layer is a ceramicized silicone rubber tape wrapped around the insulating inner sheath. The flame-retardant inner sheath is a flame-retardant silicone rubber material extruded and covering the water-blocking wrapping tape layer.

[0058] The main innovations of this invention are as follows:

[0059] 1. The cable of this product is equipped with a ceramicized silicone rubber wrapping layer, which has excellent flame retardant properties and low heat generation during combustion. The ceramicized material used forms a hard protective layer at high temperatures above 350℃, with honeycomb-like pores inside, which can play a good role in heat insulation. At the same time, the material has good shelling performance during heating, does not drip, and has good low smoke performance.

[0060] 2. This product employs a combination of flame-retardant wrapping tape and a flame-retardant inner sheath. The flame-retardant inner sheath consists of flame-retardant silicone rubber extruded over the water-blocking wrapping tape. This material is halogen-free, produces low smoke during combustion, and exhibits excellent flame-retardant properties, providing dual flame-retardant protection. The ceramicized silicone rubber tape forms a hard, ceramic-like protective layer at high temperatures, which, combined with the flame-retardant silicone rubber, provides excellent flame-retardant and heat-insulating performance. This combined structural design allows the cable to remain undamaged for a longer period in the event of a fire, delaying the spread of fire and protecting the internal structure of the cable.

[0061] In a preferred embodiment, the flame-retardant silicone rubber material comprises the following components in parts by weight:

[0062] 90 parts of polymethylvinylsiloxane;

[0063] 56 parts of silicon dioxide;

[0064] 6 parts of hydroxysiloxane;

[0065] 10 parts calcium silicate;

[0066] 16 parts of composite flame retardant;

[0067] One part of hydrosiloxane;

[0068] One part of platinum vulcanizing agent.

[0069] In one specific embodiment, the composite flame retardant is a mixture of inorganic hydroxide, antimony trioxide, and magnesium aluminum carbonate layered double hydroxide, wherein the mass ratio of the inorganic hydroxide, antimony trioxide, and magnesium aluminum carbonate layered double hydroxide is 5:1:3. Through the composite flame retardant, the oxygen index of the product's adhesive can reach above 36.

[0070] In the flame-retardant silicone rubber material of the present invention, polymethylvinylsiloxane is used as the base material and as the main strength component. Silica is used as a reinforcing material to improve the tensile and tear strength of the material. Hydroxysiloxane is used as an additive to increase the adhesion between the polymethylvinylsiloxane and silica components. Calcium silicate is added to prevent combustion crust formation and dripping.

[0071] The flame-retardant silicone rubber material of this invention meets the B1 flammability rating. The product performance test results are as follows:

[0072] (1) Vertical combustion: Tested according to GB / T10707-2008, the sample size is 130mm×13mm×3mm.

[0073] (2) Vitrification strength: Tested according to GB / T6569-2006, using a three-point bending fixture with a span of 40 mm and a beam moving speed of 0.5 mm / min. The bending strength of the test specimen is taken as its vitrification strength. The median value is taken after testing 5 specimens in parallel. The sample size is 70 mm × 6 mm × 4 mm. It is placed in a high-temperature box furnace, heated to the target temperature at 3 °C / min and kept at that temperature for a certain time before being naturally cooled to room temperature and taken out.

[0074] The product performance, after testing, is shown in Tables 1 and 2:

[0075] Table 1. Vertical combustion test results of flame-retardant silicone rubber materials

[0076]

[0077] Table 2 Performance test results of flame-retardant silicone rubber materials

[0078]

[0079] In a preferred embodiment, the insulating inner sheath is an extruded ceramicized silicone rubber material covering a water-blocking wrapping tape layer. Specifically, the ceramicized silicone rubber material comprises the following components in parts by weight:

[0080] 80 parts of α,ω-terminated hydroxyl polydimethylsiloxane;

[0081] 40 parts of fumed silica;

[0082] 20 parts of modified nano-ceramic clay;

[0083] 6 parts of 500 viscosity silicone oil;

[0084] 10 parts of composite flame retardant;

[0085] 20 parts of vitrifying powder;

[0086] 1 part of crosslinking aid;

[0087] One part of platinum vulcanizing agent.

[0088] In one specific embodiment, the composite flame retardant is a mixture of inorganic hydroxide, antimony trioxide, and magnesium aluminum carbonate layered double hydroxide, wherein the mass ratio of the inorganic hydroxide, antimony trioxide, and magnesium aluminum carbonate layered double hydroxide is 5:1:3. Through the composite flame retardant, the oxygen index of the product's adhesive can reach above 36.

[0089] In one specific embodiment, the modified nano-ceramic is prepared by the following method:

[0090] (1) Raw material mixing: Nano-clay is mixed with aminopropyltriethoxysilane to obtain a mixture; wherein, the amount of aminopropyltriethoxysilane is 3-5% of the mass of nano-clay;

[0091] (2) Heating and stirring: Heat the mixture to 50-60°C and stir continuously for 20-30 minutes;

[0092] (3) Add nano silica: Add 1.5% of the total mass of nano silica to the heated and stirred mixture;

[0093] (4) High-speed dispersion: The mixture with added nano-silica is subjected to high-speed dispersion treatment to obtain modified nano-ceramic.

[0094] In this invention, modified nano-ceramic clay, due to its nanoscale dispersion and surface modification, can significantly improve the hardness, strength, and toughness of the material. The performance of the nano-ceramic composite material at high temperatures is improved, including increased hardness and strength. Pressure resistance and impact resistance: Modified nano-ceramic clay enhances the material's barrier and airtightness, exhibiting good pressure resistance and impact resistance. Heat sealing performance: It features high heat sealing strength and good heat sealing performance.

[0095] The ceramicized silicone rubber material of this invention meets the B1 flammability rating. The product performance test results are as follows:

[0096] (1) Vertical combustion: Tested according to GB / T10707-2008, the sample size is 130mm×13mm×3mm.

[0097] (2) Vitrification strength: Tested according to GB / T6569-2006, using a three-point bending fixture with a span of 40 mm and a beam moving speed of 0.5 mm / min. The bending strength of the test specimen is taken as its vitrification strength. The median value is taken after testing 5 specimens in parallel. The sample size is 70 mm × 6 mm × 4 mm. It is placed in a high-temperature box furnace, heated to the target temperature at 3 °C / min and kept at that temperature for a certain time before being naturally cooled to room temperature and taken out.

[0098] The product performance, after testing, is shown in Tables 3 and 4:

[0099] Table 3. Vertical combustion test results of ceramicized silicone rubber materials

[0100]

[0101] Table 4 Performance test results of ceramicized silicone rubber materials

[0102]

[0103] In one specific implementation, the metal sheath layer is a corrugated aluminum sleeve.

[0104] In one specific implementation, the composite cable core includes a plurality of insulated cores, each insulated core including a conductor and an insulating layer covering the outer surface of the conductor;

[0105] The insulating layer is a polyvinyl chloride sheath material extruded onto the conductor.

[0106] In one specific implementation, the water-blocking wrapping layer is formed by wrapping water-blocking tape. Water-blocking yarn is placed to fill the gaps in the composite cable core.

[0107] Specifically, the conductor is either the first conductor structure or the second conductor structure in GB / T 3956.

[0108] In a preferred embodiment, the outer sheath is made of ceramicized silicone rubber material.

[0109] This invention verifies the performance of polyvinyl chloride control circuit products, tests the insulation and sheath mechanical properties, insulation electrical properties, and performs short-circuit integrity tests on the insulated cores, fire resistance tests and combustion tests on the finished cables.

[0110] (1) The control cable was subjected to a 3000V×5min withstand voltage test, and the insulated core was subjected to a 2500V×5min immersion withstand voltage test and a 168h immersion insulation resistance retention test. Test data: Withstand voltage test: no breakdown. Immersion withstand voltage test: no breakdown. After immersion in water for 168h, the insulation resistance retained 90%, which is similar to that of cross-linked polyethylene material.

[0111] It can be seen that the water immersion insulation resistance retention rates of the silicone rubber material of the present invention and cross-linked polyethylene are very close, indicating that silicone rubber has a strong resistance to moisture.

[0112] (2) Simulate the stable high current required for a short circuit in the test cable using the test equipment, causing the conductor to melt within 3 seconds after energization. The test is conducted at (25±5)℃. The sample is placed in the test environment for at least 24 hours. Cut an insulated core with a length of (200±5)mm, and strip 30-35mm of insulation from both ends. Fix both ends to the current terminals of the test equipment. Turn on the power switch of the test equipment and observe whether the tested insulated core conductor melts or the insulation catches fire at high temperature. If any of the above occurs, the power switch should be turned off immediately to ensure the safety of the test equipment.

[0113] The test results show that when the insulated core sample of this work is short-circuited and melted, the insulation layer remains intact and undamaged, without cracking or ignition.

[0114] (3) B1 flame retardant characteristics requirements: A comprehensive combustion performance test was conducted on the two materials and the cable products made from these materials. The test results are shown in Table 5.

[0115] Table 5. Test results of the combustion performance of finished cables

[0116] As shown in Table 5, the performance of the control cable meets the requirements of GB 51298—2018 "Fire Protection Design Standard for Metro" for power control circuits in fire-resistant applications.

[0117]

[0118] Other structures of the polyvinyl chloride control cable described in this embodiment are available in the prior art.

[0119] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Therefore, any modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A polyvinyl chloride control cable, characterized in that, It includes, from the inside out, a composite cable core, a water-blocking wrapping tape layer, an insulating inner sheath, a flame-retardant wrapping tape layer, a flame-retardant inner sheath, a metal sheath layer, and an outer sheath; The flame-retardant wrapping tape layer is a ceramicized silicone rubber tape wrapped around the insulating inner sheath; The flame-retardant inner sheath is made of flame-retardant silicone rubber material extruded and covered on a water-blocking wrapping tape layer. The insulating inner sheath is made of ceramicized silicone rubber material extruded and covered on a water-blocking wrapping tape layer. The ceramicized silicone rubber material comprises the following components in parts by weight: 80 parts of α,ω-terminated hydroxyl polydimethylsiloxane; 40 parts of fumed silica; 20 parts of modified nano-ceramic clay; 6 parts of 500 viscosity silicone oil; 10 parts of composite flame retardant; 20 parts of vitrifying powder; 1 part of crosslinking aid; 1 part platinum vulcanizing agent; The modified nano-ceramic is prepared by the following method: (1) Raw material mixing: Nano-ceramic clay is mixed with aminopropyltriethoxysilane to obtain a mixture; wherein, the amount of aminopropyltriethoxysilane is 3-5% of the mass of nano-ceramic clay; (2) Heating and stirring: Heat the mixture to 50-60°C and stir continuously for 20-30 minutes; (3) Add nano silica: Add 1.5% of the total mass of nano silica to the heated and stirred mixture; (4) High-speed dispersion: The mixture with added nano-silica is subjected to high-speed dispersion treatment to obtain modified nano-ceramic.

2. The polyvinyl chloride control cable according to claim 1, characterized in that, The flame-retardant silicone rubber material comprises the following components in parts by weight: 90 parts of polymethylvinylsiloxane; 56 parts of silicon dioxide; 6 parts of hydroxysiloxane; 10 parts calcium silicate; 16 parts of composite flame retardant; One part of hydrosiloxane; One part of platinum vulcanizing agent.

3. The polyvinyl chloride control cable according to claim 2, characterized in that: The composite flame retardant is a mixture of inorganic hydroxide, antimony trioxide, and magnesium aluminum carbonate hydrotalcite, with a mass ratio of 5:1:

3.

4. The polyvinyl chloride control cable according to claim 1, characterized in that: The metal sheath layer is a corrugated aluminum sheath.

5. The polyvinyl chloride control cable according to claim 1, characterized in that: The composite cable core includes a plurality of insulated cores, each insulated core including a conductor and an insulating layer covering the outer surface of the conductor; The insulating layer is a polyvinyl chloride sheath material extruded onto the conductor.

6. The polyvinyl chloride control cable according to claim 5, characterized in that: The conductor is either the first conductor structure or the second conductor structure in GB / T 3956.

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