A high-temperature and low-temperature resistant radiation-resistant high-voltage cable and its preparation method and application

Abstract

The invention discloses a high-temperature and low-temperature radiation-resistant high-voltage cable and a preparation method and application thereof, and relates to the field of cable technology. The high-voltage cable comprises a core wire assembly, and a rubber insulation layer, a shielding layer and a sheath layer are arranged outside the core wire assembly. The rubber insulation layer is composed of silicone rubber, and the silicone rubber comprises the following raw materials by mass: 80 to 100 parts of methylphenyl vinyl silicone rubber, 2 to 5 parts of silane coupling agent, 1 to 2 parts of hollow silica, 1 to 1.5 parts of fumed silica, 1.0 to 1.8 parts of double two five and 0.2 to 0.8 parts of nano calcium oxide, and the mass ratio of phenyl to silicon atom in the methylphenyl vinyl silicone rubber is 0.5 to 1:10. The high-voltage cable provided by the invention has the characteristics of high voltage resistance and a wide applicable temperature range.

Description

Technical Field

[0001] The invention belongs to the technical field of cables, and in particular is a high-temperature and radiation-resistant high-voltage cable and a preparation method and application thereof. Background Art

[0002] The operation of medical equipment has unique specifications and environmental conditions, which makes the performance of the cable assemblies connecting these devices also critical. Medical cables must achieve excellent operating performance under the huge pressure of hospitals, clinics and emergency care conditions, while adapting to various environmental changes. For example, in X-ray machines and CT machines, the high-voltage generator and the X-ray tube are connected together by two high-voltage wires. The use conditions of the wires are very harsh and need to be resistant to high voltage for a long time and stable. At the same time, in order to kill some specific bacteria or viruses, medical workers will use low-temperature or high-temperature sterilization methods to maintain some medical equipment, so the cables used in medical equipment need to have high and low temperature resistance and certain radiation resistance.

[0003] At present, the product structure of high-voltage cables on the market mainly includes bare copper conductor, insulation layer, silicone rubber insulation and sheath layer. Existing high-voltage cables mostly use polyolefin materials to cover the outside of the conductor layer to form an insulating sheath to insulate the high-voltage cables. However, most of them use voltages of DC 15kV and below, and operating temperatures of -20℃~150℃. High-voltage resistance, temperature resistance range and radiation resistance cannot be taken into account at the same time. Summary of the invention

[0004] The object of the present invention is to provide a high-temperature and radiation-resistant high-voltage cable to solve at least one aspect of the problems and defects raised in the above-mentioned background technology.

[0005] The present invention also provides a method for preparing the high-temperature and radiation-resistant high-voltage cable.

[0006] The present invention also provides application of the high-temperature-resistant and radiation-resistant high-voltage cable.

[0007] A first aspect of the present invention provides a high-temperature and low-temperature resistant and radiation-resistant high-voltage cable, comprising a core wire assembly, wherein the core wire assembly is provided with an insulating layer, a shielding layer and a sheath layer;

[0008] The insulating layer is made of insulating rubber;

[0009] The insulating rubber comprises the following raw materials in parts by weight:

[0010] 80 to 100 parts of methylphenyl vinyl silicone rubber, 2 to 5 parts of silane coupling agent, 1 to 2 parts of hollow silica, 1 to 1.5 parts of fumed silica, 1.0 to 1.8 parts of bis(25-pentane) and 0.2 to 0.8 parts of nano calcium oxide;

[0011] The mass ratio of phenyl to silicon atoms in the methylphenyl vinyl silicone rubber is 0.5 to 1:10.

[0012] According to one technical solution of the high-temperature and low-temperature resistant and radiation-resistant high-voltage cable technical solution of the present invention, there are at least the following beneficial effects:

[0013] The present invention isolates and protects the wire core through the insulating layer, shielding layer and sheath layer of the core wire assembly, achieving high and low temperature resistance while achieving high voltage resistance.

[0014] The present invention selects methylphenyl vinyl silicone rubber as the main material of the insulating layer. The rubber has the characteristics of high and low temperature resistance. At the same time, the introduction of phenyl destroys the regularity of the dimethylsiloxane structure, greatly reduces the crystallization temperature of the polymer, and also reduces the dielectric constant of the rubber, improves the radiation resistance of the silicone rubber, and further improves the insulation performance and low temperature resistance.

[0015] The present invention achieves the performance of high pressure resistance, low temperature resistance and radiation resistance by controlling the mass ratio of phenyl atoms to silicon atoms. If the mass ratio is too low, the regularity of the dimethylsiloxane structure cannot be effectively destroyed, and the low temperature resistance cannot be further improved. Meanwhile, if the mass ratio is too low, the phenyl content is small, and the effect of increasing the free volume cannot be achieved, thereby failing to effectively reduce the dielectric constant of the rubber and further achieving the effect of high pressure resistance. If the mass ratio is too high, the rigid groups in the rubber increase, the processing performance decreases, and it is not conducive to the subsequent cross-linking of the rubber.

[0016] Hollow silica is added to the insulating rubber of the present invention. Since the dielectric constant of air is lower, the addition of hollow silica will introduce part of air, which can improve the insulation performance of the main insulating rubber, so that it has the characteristic of high-voltage resistance. The silane coupling agent can improve the compatibility of methylphenyl vinyl silicone rubber and inorganic filler in the rubber. One end of the silane coupling agent can be combined with the rubber, and the other end can be combined with the hollow silica, so that the hollow silica can be better fused, thereby improving the high-voltage resistance. The gas phase white carbon black has the function of reinforcing the rubber, the nano calcium oxide plays a drying role when the rubber is mixed, and the di-25 as a vulcanizing agent plays a role of rubber cross-linking.

[0017] The present invention can reasonably coordinate the performance of various raw materials by controlling the mass fraction of raw materials for preparing insulating rubber, and can be used for the insulating layer of the cable to achieve the characteristics of high voltage resistance and high and low temperature resistance.

[0018] In some specific embodiments of the present invention, the thickness of the insulating layer is 2 mm to 8 mm.

[0019] In some specific embodiments of the present invention, the thickness of the insulating layer is 4 mm to 7 mm.

[0020] In the present invention, the characteristic of high voltage resistance can be achieved by controlling the thickness of the insulation layer. If the thickness is too low, the insulation performance is poor and the high voltage resistance requirement cannot be met. If the thickness is too high, the heat is difficult to dissipate. After the cable is powered on for too long, more and more heat accumulates, which will affect the normal service life of the cable.

[0021] In some specific embodiments of the present invention, the shielding layer is composed of a semi-conductive rubber outer layer, a semi-conductive tape outer shielding layer and a metal wire braided shielding layer from inside to outside;

[0022] The thickness of the semi-conductive rubber outer layer is 0.5 mm to 1.2 mm.

[0023] The voltage in the high-voltage cable of the present invention is very high, and the generated electric field is very strong. The shielding layer can effectively prevent the high-voltage power cable from interfering with the outside world and improve the electric field distribution. The semi-conductive rubber outer layer can have good contact with the insulating layer internally and have the same potential as the semi-conductive tape outer shielding layer and the metal wire braided shielding layer externally, thereby avoiding the phenomenon of local discharge between the insulating layer and the metal wire braided shielding layer. The semi-conductive tape can make the semi-conductive rubber outer layer and the insulating layer fit more closely, and the metal wire braided shielding layer has the function of electromagnetic shielding.

[0024] In some specific embodiments of the present invention, the core wire assembly is composed of a main wire unit, a ground wire unit and a semi-conductive rubber inner layer;

[0025] The main line unit is provided with an F4 insulation layer outside;

[0026] A layer of semi-conductive tape is arranged outside the ground line unit.

[0027] The temperature resistance level of the F4 insulation layer in the present invention can reach -100°C to 260°C, which brings excellent high and low temperature resistance performance to the high voltage cable.

[0028] The core wire assembly of the present invention is formed by gluing the main wire unit and the ground wire unit, which easily causes gaps and makes the surface rough. The semi-conductive rubber inner layer coating can reduce the gaps and at the same time has good contact with the insulation layer.

[0029] In some specific embodiments of the present invention, the sheath layer is composed of methylphenylvinyl silicone rubber;

[0030] The thickness of the sheath layer is 1.8 mm to 2.5 mm.

[0031] The sheath layer in the present invention plays a role in protecting the cable from being scratched, and the methylphenyl vinyl silicone rubber is used as the sheath layer, which has high and low temperature resistance. If the thickness of the sheath layer is too low, the inner core wire assembly is easily scratched and fails to achieve the protective effect. If the thickness of the sheath layer is too high, the cable becomes thicker, the cost is too high, and the flexibility of the cable becomes poor.

[0032] In some specific embodiments of the present invention, the thickness of the inner layer of semi-conductive rubber is 0.8 mm to 1.2 mm.

[0033] A second aspect of the present invention provides a method for preparing a high-temperature and low-temperature resistant radiation-resistant high-voltage cable, comprising the following steps:

[0034] S1, mixing the methylphenyl vinyl silicone rubber, 2 to 5 parts of a silane coupling agent, hollow silica, fumed silica, bis(250)-bis(250) and nano-calcium oxide to obtain an insulating rubber;

[0035] S2, wrapping the main line unit with an F4 insulation layer and the ground line unit with a semi-conductive tape, and then gluing them together to obtain a cable core, and then extruding a semi-conductive rubber inner layer on the outer surface of the cable to obtain a core wire assembly;

[0036] S3, extruding the insulating rubber onto the outer surface of the core wire assembly to obtain an insulating rubber layer;

[0037] S4. Sequentially coat the shielding layer and the sheath layer to obtain a high-voltage cable.

[0038] According to one technical solution of the technical solution of the method for preparing the high-temperature and low-temperature resistant and radiation-resistant high-voltage cable of the present invention, there are at least the following beneficial effects:

[0039] The present invention mixes raw materials for preparing insulating rubber to obtain insulating rubber that is resistant to high voltage and high and low temperatures, and uses an inner layer of semi-conductive rubber to protect the cable core by extrusion to form a core wire assembly, and then extrude the insulating rubber onto the surface of the core wire assembly again by extrusion. This method can reduce gaps generated when the cable core is glued.

[0040] In some specific embodiments of the present invention, the mixing time is 1.5 h to 3 h.

[0041] In the present invention, if the mixing time is controlled to be too short, the hollow silica and the fumed silica are difficult to mix evenly, and if the mixing time is too long, the hollow silica is easily broken.

[0042] In some specific embodiments of the present invention, the mixing temperature is 90°C to 120°C.

[0043] If the mixing temperature is too low, the crosslinking degree will be too low and the high and low temperature resistance performance cannot be achieved. In addition, the methylphenyl vinyl silicone rubber has poor fluidity, and silica, fumed silica and nano calcium oxide are difficult to mix evenly. If the mixing temperature is too high, the mixing energy consumption will be high.

[0044] In some specific embodiments of the present invention, the gluing pitch multiple is 6 to 10 times.

[0045] A third aspect of the present invention provides an application of a high-temperature-resistant, radiation-resistant high-voltage cable in the preparation of a medical cable.

[0046] Compared with the prior art, the technical solution of the present invention has the following beneficial technical effects:

[0047] The present invention reduces the dielectric constant of the insulating layer by adding hollow silica to the insulating layer and controlling the mass ratio of phenyl to silicon atoms, so that the cable has the characteristic of high voltage resistance. At the same time, the silicon-oxygen bonds contained in the insulating layer material provide high and low temperature resistance. The insulating layer is coated on the outside of the core wire component by extrusion, and the prepared cable has the characteristics of high voltage resistance and high and low temperature resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to facilitate understanding by those skilled in the art, the present invention is further described below with reference to the accompanying drawings.

[0049] Figure 1 It is a schematic diagram of the cross-sectional structure of a high-temperature-resistant and radiation-resistant high-voltage cable in an embodiment of the present invention.

[0050] Reference numerals:

[0051] 100. Ground wire unit; 101. Semi-conductive tape; 102. Main line unit; 103. F4 insulation layer; 104. Semi-conductive rubber inner shielding layer; 105. Rubber insulation layer; 106. Semi-conductive tape outer shielding layer; 107. Metal wire braided shielding layer; 108. Sheath layer. DETAILED DESCRIPTION

[0052] The following will be combined with the embodiments to clearly and completely describe the concept of the present invention and the technical effects produced, so as to fully understand the purpose, characteristics and effects of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative work are all within the scope of protection of the present invention.

[0053] In the description of the present invention, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0054] If the specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or conditions recommended by the manufacturer. If the manufacturers of the reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0055] Specific embodiments of the present invention are described in detail below.

[0056] The silane coupling agent in the present invention is KH550.

[0057] The number average molecular weight of the methylphenylvinyl silicone rubber in the present invention is 500,000.

[0058] The average particle size of the nano calcium oxide in the present invention is 20 nm.

[0059] The hollow silica used in the present invention is graded as YM-SiO2-ZKW12.

[0060] The solid silicon dioxide used in the present invention is graded as YM-SiO2W12.

[0061] The grade of the methyl vinyl silicone rubber used in the present invention is DR-110-1.

[0062] The specific embodiments of the present invention are described in detail below.

[0063] Example 1

[0064] The present embodiment is a high-temperature and radiation-resistant high-voltage cable, comprising a core wire assembly, and a rubber insulation layer, a shielding layer and a sheath layer are arranged outside the core wire assembly.

[0065] The rubber insulating layer is composed of silicone rubber, which is composed of the following raw materials in parts by weight:

[0066] 100 parts of methylphenyl vinyl silicone rubber, 3 parts of silane coupling agent, 2 parts of hollow silica, 1 part of fumed silica, 1.5 parts of bis(250)-1,500 and 0.3 parts of nano calcium oxide;

[0067] The mass ratio of phenyl in methylphenyl vinyl silicone rubber to silicon atom in methylphenyl vinyl silicone rubber is 0.8:10.

[0068] Reference Figure 1As shown, the high-temperature and low-temperature radiation-resistant high-voltage cable includes a ground wire unit 100 and a main wire unit 102 from the inside to the outside. The ground wire unit is twisted with 42 / 0.15 tinned copper wires, and the main wire unit is twisted with 19 / 0.32 silver-plated copper conductors. A layer of semi-conductive tape 101 is wrapped around the outer surface of the ground wire unit to play a role of preliminary insulation and protection. A layer of F4 insulation layer 103 with a thickness of 0.4 mm is wrapped around the outer surface of the main wire unit. The F4 insulation layer has excellent temperature resistance. Multiple main wire units and ground wire units are twisted into a cable, and semi-conductive rubber is extruded on the outer surface of the cable. The rubber inner shielding layer 104 is insulated and shielded to effectively eliminate gaps generated during twisting. A rubber insulating layer 105 with a thickness of 5.0 mm is extruded on the outer surface of the semi-conductive rubber inner shielding layer to play a major role in insulation and heat insulation. A 0.6 mm semi-conductive rubber shielding outer layer is tightly extruded on the outer surface of the rubber insulating layer to avoid local discharge. A metal wire braided shield 107 is then wrapped around for electromagnetic shielding. Finally, a sheath layer 108 is put on the outermost layer. The sheath layer is made of high and low temperature resistant methylphenyl vinyl silicone rubber and has a thickness of 2.2 mm.

[0069] The preparation method of the high-temperature and low-temperature resistant and radiation-resistant high-voltage cable of this embodiment comprises the following steps:

[0070] S1. Weigh 100 parts of methylphenyl vinyl silicone rubber, 3 parts of silane coupling agent, 2 parts of hollow silica, 1 part of fumed silica, 1.2 parts of bis(250)-pentane and 0.5 parts of nano calcium oxide, mix for 2 hours at a temperature of 100° C. to obtain insulating rubber;

[0071] S2, twist 42 / 0.15 tinned copper wire into a ground wire unit and wrap it with a semi-conductive tape, then twist 19 / 0.32 silver-plated copper conductor into a main wire unit and wrap it with an F4 insulation layer;

[0072] S3, twisting two ground wire units and two main wire units into a cable, controlling the pitch multiple to 8 times during twisting, to obtain a cable core, and extruding and coating a layer of semi-conductive rubber inner layer on the outer surface of the cable core to obtain a core wire assembly;

[0073] S4, extruding a semi-conductive rubber onto the outer surface of the core wire assembly to form a semi-conductive rubber inner shielding layer, and then extruding the insulating rubber obtained in S1 onto the semi-conductive rubber inner shielding layer to obtain a rubber insulating layer;

[0074] S5. Then extrude the semi-conductive rubber onto the outer surface of the rubber insulation layer to form a semi-conductive rubber shielding outer layer, then wrap it with a metal wire braided shield, and finally perform sheath protection to obtain a high-temperature and radiation-resistant high-voltage cable.

[0075] Example 2

[0076] This embodiment is a high-voltage cable that is resistant to high and low temperatures and radiation, and the difference from Embodiment 1 is that the thickness of the rubber insulation layer is 3 mm.

[0077] Example 3

[0078] This embodiment is a high-voltage cable that is resistant to high and low temperatures and radiation. The difference from Embodiment 1 is that the cable contains 90 parts of methylphenylvinyl silicone rubber.

[0079] Comparative Example 1

[0080] This comparative example is a high-temperature and radiation-resistant high-voltage cable, which differs from Example 1 in that the hollow silica is replaced by solid silica.

[0081] Comparative Example 2

[0082] This comparative example is a high-temperature and radiation-resistant high-voltage cable, which is different from Example 1 in that the methyl phenyl vinyl silicone rubber is replaced by methyl vinyl silicone rubber that does not contain phenyl.

[0083] The high-temperature-resistant and radiation-resistant high-voltage cables obtained in Examples 1 to 3 and Comparative Examples 1 to 2 were tested for withstand voltage performance at 25° C. The results are shown in Table 1.

[0084] Withstand voltage test: Refer to GB / T3048-2007 Electrical performance test method for wires and cables, Part 8 AC voltage test.

[0085] The high-temperature-resistant and radiation-resistant high-voltage cables obtained in Examples 1 to 3 and Comparative Examples 1 to 2 were subjected to heat shock resistance tests and impact embrittlement tests. The results are shown in Table 1.

[0086] Thermal shock resistance test and impact embrittlement test: refer to GB / T32129-2015 halogen-free low-smoke flame-retardant cable materials for wires and cables.

[0087] High temperature resistance refers to the maximum temperature at which the cable does not crack after a 1-hour heat shock test.

[0088] The low temperature resistance performance refers to the temperature corresponding to when the number of cable failures is less than 15 during the impact embrittlement test by lowering the test temperature and conducting multiple tests.

[0089] Table 1 Performance test of high-temperature and low-temperature resistant and radiation-resistant high-voltage cables obtained in Examples 1 to 3 and Comparative Examples 1 to 2

[0090] - Maximum withstand voltage / kV Maximum temperature resistance / ℃ Minimum temperature resistance / ℃ Example 1 75 200 -100 Example 2 73 180 -95 Example 3 74 195 -90 Comparative Example 1 51 175 -80 Comparative Example 2 67 160 -50

[0091] It can be seen from Table 1 that after adding a certain amount of hollow silica, the maximum high voltage resistance value is significantly improved and the insulation performance is improved, mainly because the dielectric constant of the cable rubber insulation layer is reduced after the addition of hollow silica; it can also be seen from Table 1 that the use of phenyl-modified methyl vinyl silicone rubber as rubber insulation and sheath layer can improve the heat resistance and low temperature resistance of the cable, mainly because phenyl changes the regularity of methyl vinyl silicone rubber and reduces the crystallization temperature of the polymer, thereby improving the heat resistance and low temperature resistance of the cable.

[0092] In summary, the present invention reduces the dielectric constant of the insulating layer by adding hollow silica to the insulating layer and controlling the mass ratio of phenyl to silicon atoms, so that the cable has the characteristic of high voltage resistance. At the same time, the silicon-oxygen bonds contained in the insulating layer material provide high and low temperature resistance. The insulating layer is coated on the outside of the core wire component by extrusion. The prepared high-temperature and radiation-resistant high-voltage cable can be used in medical equipment, can withstand 75kV high voltage, and can withstand low temperatures of -100°C and high temperatures of 200°C, and can withstand radiation rays.

[0093] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A high-temperature and radiation-resistant high-voltage cable, characterized in that: It comprises a core wire assembly, and the core wire assembly is provided with a rubber insulation layer, a shielding layer and a sheath layer; The rubber insulation layer is made of silicone rubber; The silicone rubber is composed of the following raw materials in parts by weight: 80 to 100 parts of methylphenyl vinyl silicone rubber, 2 to 5 parts of silane coupling agent, 1 to 2 parts of hollow silica, 1 to 1.5 parts of fumed silica, 1.0 to 1.8 parts of bis(25-pentylene)diol and 0.2 to 0.8 parts of nano calcium oxide; The mass ratio of phenyl to silicon atoms in the methylphenyl vinyl silicone rubber is 0.5 to 1:10; The number average molecular weight of the methylphenyl vinyl silicone rubber is 500,000; The thickness of the rubber insulation layer is 2 mm to 8 mm; The core wire assembly is composed of a main wire unit, a ground wire unit and a semi-conductive rubber inner shielding layer; The main line unit is provided with an F4 insulation layer outside; A layer of semi-conductive tape is arranged outside the ground line unit.

2. The high-temperature and radiation-resistant high-voltage cable according to claim 1, characterized in that: The shielding layer is composed of a semi-conductive tape outer shielding layer and a metal wire braided shielding layer; The thickness of the outer shielding layer of the semi-conductive tape is 0.5 mm to 1.2 mm.

3. The high-temperature and radiation-resistant high-voltage cable according to claim 1, characterized in that: The sheath layer is made of methylphenyl vinyl silicone rubber; The thickness of the sheath layer is 1.8 mm to 2.5 mm.

4. The high-temperature and radiation-resistant high-voltage cable according to claim 3, characterized in that: The thickness of the semi-conductive rubber inner shielding layer is 0.8 mm to 1.2 mm.

5. A method for preparing a high-temperature and low-temperature resistant and radiation-resistant high-voltage cable as claimed in any one of claims 1 to 4, characterized in that: The following steps are involved: S1, mixing the methylphenyl vinyl silicone rubber, silane coupling agent, hollow silica, fumed silica, bis(250)-pentanediol and nano calcium oxide to obtain insulating rubber; S2, wrapping the main line unit with an F4 insulation layer and the ground line unit with a semi-conductive tape, and then twisting them to obtain a cable core, and then extruding a semi-conductive rubber inner shielding layer on the outer surface of the cable core to obtain a core wire assembly; S3, extruding the insulating rubber onto the outer surface of the core wire assembly to obtain an insulating rubber layer; S4, sequentially coating the shielding layer and the sheath layer to obtain a high-temperature and radiation-resistant high-voltage cable.

6. The method according to claim 5, characterized in that The mixing time is 1.5h~3h; The mixing temperature is 90°C to 120°C.

7. The method according to claim 6, characterized in that The twisting pitch multiple is 6 to 10 times.

8. Use of the high-temperature-resistant and radiation-resistant high-voltage cable according to any one of claims 1 to 4 in the preparation of medical cables.

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