Electromagnetic shielded cable and method of manufacturing the same

Abstract

The application discloses an electromagnetic shielding cable and a preparation method thereof, and relates to the technical field of cables. The electromagnetic shielding cable comprises a composite shielding layer composed of a first film layer, a braided layer and a second film layer, wherein the braided layer is woven by conductive fibers, the first film layer and the second film layer are both coated by winding a composite magnetic conductive film, and the composite magnetic conductive film comprises a film base material and a magnetic conductive plating layer. The film base material is prepared by polyetherimide and ammoniated conductive filler, and the magnetic conductive plating layer is deposited on one side surface of the film base material by containing iron-cobalt alloy. The composite shielding layer formed by coating the specific composite magnetic conductive film on the inner and outer sides of the braided layer has excellent shielding performance and a wider shielding frequency spectrum, which is beneficial to shielding most of high-frequency and low-frequency electromagnetic interference.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of cables, in particular to an electromagnetic shielding cable and a preparation method thereof. BACKGROUND

[0002] Cables have many different structures, one of which is electromagnetic shielding cable. Electromagnetic shielding cable generally refers to signal transmission line that can still have high-quality transmission performance in a strong electromagnetic interference environment. Shielding cable not only shields electromagnetic radiation caused by signal current from the inside of the cable to prevent the loss of transmission information, but also shields high-frequency magnetic fields from the outside of the cable to reduce the impact on signal transmission, so shielding cable can play an important role in aerospace, communication industry, radar base station and other occasions.

[0003] At present, conventional electromagnetic shielding cables generally set a metal braid layer or a metal foil to achieve electromagnetic shielding. Since the metal braid layer and the metal foil have high conductivity, they can have strong reflection and attenuation effects on high-frequency electromagnetic radiation through effective grounding. However, in actual application, communication cables and power cables are usually configured in the same small space at the same time. During the start and stop of the equipment, the transient current change in the power cable will induce strong electromagnetic radiation. At the same time, since the frequency of such electromagnetic radiation is low, the shielding effect of the conventional metal shielding layer on such electromagnetic radiation is poor, so the signal transmission of the communication cable will be significantly affected. Therefore, by optimizing the shielding structure of the electromagnetic shielding cable, broadening the electromagnetic shielding spectrum of the cable, making it able to shield most of the high-frequency and low-frequency electromagnetic interference, and further making it lightweight and easy to bend, it has great value and significance for the development of the cable industry. SUMMARY

[0004] In order to further optimize the shielding structure of the electromagnetic shielding cable and improve the shielding effect of the electromagnetic shielding cable, the present application provides an electromagnetic shielding cable and a preparation method thereof.

[0005] In a first aspect, the electromagnetic shielding cable provided by the present application adopts the following technical scheme:

[0006] An electromagnetic shielding cable, comprising a bundled cable core, an inner insulating layer, a composite shielding layer and an outer insulating layer arranged in sequence from inside to outside, wherein the composite shielding layer comprises a first film layer, a braid layer and a second film layer arranged in sequence from inside to outside.

[0007] The braid layer is woven from conductive fibers.

[0008] The first film layer and the second film layer are both wrapped by a composite magnetic conductive film, the composite magnetic conductive film comprises a film substrate and a magnetic conductive plating layer arranged on one side of the film substrate, the film substrate of the composite magnetic conductive film is prepared by polyetherimide and ammoniated conductive filler, and the magnetic conductive plating layer is formed by depositing an iron-cobalt alloy on one side surface of the film substrate.

[0009] By adopting the above technical scheme, the composite magnetic conductive film with the magnetic conductive plating layer is arranged on the inner and outer sides of the braided layer, the formed composite shielding layer has more excellent shielding performance and a wider shielding spectrum, has excellent shielding efficiency not only for high-frequency electric field but also for low-frequency magnetic field and low-frequency electric field, and thus is beneficial to improving the comprehensive shielding effect of the electromagnetic shielding cable and making the electromagnetic shielding cable shield most of high-frequency and low-frequency electromagnetic interference.

[0010] Optionally, the film substrate of the composite magnetic conductive film comprises the following raw materials by weight:

[0011] Polyetherimide: 100 parts;

[0012] Ammoniated conductive filler: 1-2 parts;

[0013] Sodium dodecyl sulfonate: 8-12 parts;

[0014] The ammoniated conductive filler is prepared from amino silane modified nano conductive filler, and the nano conductive filler is a mixture of one of nano carbon powder or multi-walled carbon nanotube and nano metal powder.

[0015] By adopting the above technical scheme, the composite magnetic conductive film with the conductive performance and the mechanical performance can be prepared, and thus it is beneficial to improving the shielding performance of the composite shielding layer, and the composite shielding layer is not easy to be broken or disconnected under the conditions of cable bending, pressure and impact, which is beneficial to improving the durability of the composite shielding layer and prolonging the service life of the electromagnetic shielding cable.

[0016] Optionally, the preparation method of the ammoniated conductive filler comprises the following steps:

[0017] The nano conductive filler is added into anhydrous ethanol, and after being fully ultrasonically dispersed, polyvinylpyrrolidone and gamma-aminopropyl triethoxysilane are added, continuous stirring reaction is performed, filtration and multiple cleaning with anhydrous ethanol are performed, and after drying, the ammoniated conductive filler is obtained.

[0018] Optionally, the mixing mass ratio of the nano conductive filler, the polyvinylpyrrolidone and the gamma-aminopropyl triethoxysilane is 10:(1-2):(2-3).

[0019] By adopting the technical scheme, the polyvinylpyrrolidone and the gamma-aminopropyl triethoxysilane are used to modify the surface of the nano-conductive filler, and the synergistic effect between the two is conducive to improving the dispersibility and stability of the nano-conductive filler in the polyetherimide solution, effectively preventing the nano-conductive filler from agglomerating, and making the nano-conductive filler form a more uniform and continuous conductive network and structure network in the composite magnetic thin film, which is conducive to improving the shielding effectiveness and mechanical properties of the composite magnetic thin film.

[0020] Optionally, the nano-conductive filler is a mixed powder of multi-walled carbon nanotubes, nano-copper powder and nano-nickel powder, and the mixed mass ratio of the multi-walled carbon nanotubes, the nano-copper powder and the nano-nickel powder is (2-3) : (6-7.5) : (0.5-2).

[0021] By adopting the technical scheme, the multi-walled carbon nanotubes can form a dense network on the surface of the polyetherimide thin film while being wound around a small amount of fiber surface, which is conducive to improving the electrical conductivity and mechanical properties of the composite magnetic thin film, and a small amount of nano-nickel powder can significantly reduce the magnetic resistance of the thin film substrate, enhance the low-frequency magnetic field shielding effectiveness of the composite magnetic thin film, and will not significantly reduce the electrical conductivity of the composite magnetic thin film, so that the composite magnetic thin film can exhibit high comprehensive electromagnetic shielding performance by adopting the nano-conductive filler.

[0022] Optionally, the preparation method of the composite magnetic thin film comprises the following steps:

[0023] A1, polyetherimide is dissolved in N-methylpyrrolidone at 10-20wt%, heated in water bath to 60-65℃ and continuously stirred for not less than 12h, so that it is fully dissolved and dispersed, sodium dodecyl sulfonate is added, the temperature is kept and continuously stirred until it is fully dissolved, ammonia-conductive filler is added, continuously stirred and dispersed, and then ultrasonic dispersion treatment is carried out for not less than 3 times, each time for 20-30min, to prepare a spinning solution, electrospinning is carried out, and after spinning is completed, low-temperature drying is carried out to obtain a thin film substrate;

[0024] A2, the thin film substrate prepared in S1 is sent into a vacuum magnetization sputtering coating system, iron-cobalt alloy is used as target material, the vacuum degree is kept less than 1.5×10 -3 Pa, heated to 180-230℃, argon is introduced, the sputtering power is set to 80-120W, and sputtering is carried out for 5-10min, so that the iron-cobalt alloy can be uniformly deposited on one side surface of the thin film substrate to form a magnetic plating layer, and a composite magnetic thin film is obtained.

[0025] Optionally, the thickness of the thin film substrate is 0.2-0.3mm, and the thickness of the magnetic plating layer is 100-150nm.

[0026] By adopting the technical scheme, the composite magnetic conductive film with good electric conductivity, magnetic conductivity and mechanical properties can be prepared, which is beneficial to improve the shielding performance of the composite magnetic conductive film, improve the durability of the composite magnetic conductive film, prolong the service life, and further improve the shielding effect and shielding aging of the electromagnetic shielding cable.

[0027] In a second aspect, the application provides a preparation method of an electromagnetic shielding cable, which adopts the following technical scheme:

[0028] A preparation method of an electromagnetic shielding cable, comprising the following steps:

[0029] S1, first prepare a bundled cable core and an inner insulation layer, and wrap and cover the composite magnetic conductive film on the outer circumferential side of the inner insulation layer to form a first film layer;

[0030] S2, weave the electrically conductive fiber on the outer circumferential side of the first film layer to form a woven layer;

[0031] S3, wrap and cover the composite magnetic conductive film on the outer circumferential side of the woven layer again to form a second film layer;

[0032] S4, prepare an outer insulation layer to cover the outer circumferential side of the second woven layer to obtain an electromagnetic shielding cable.

[0033] By adopting the technical scheme, a cable with excellent high and low frequency electromagnetic shielding performance can be prepared, which has excellent shielding effect not only for high frequency electric field, but also for low frequency magnetic field and low frequency electric field. In addition, the preparation method of the electromagnetic shielding cable is simple, and only traditional winding equipment and weaving equipment are needed to realize the preparation of the cable, which is beneficial to subsequent large-scale production and preparation in the factory, and does not need to invest too many resources in equipment improvement, thereby reducing the cost of technical improvement.

[0034] Optionally, the electrically conductive fiber is one of nickel-plated carbon fiber or silver-plated aramid fiber.

[0035] By adopting the technical scheme, the woven layer is woven by using metalized fiber with lower density, which not only has lower material cost, but also has lighter weight and is softer, so that the overall weight and axial rigidity of the electromagnetic shielding cable can be effectively reduced, and the electromagnetic shielding cable can be lightened and more easily bent.

[0036] Optionally, in steps S1 and S3, the magnetic conductive plating layer faces one side of the woven layer when the composite magnetic conductive film is wrapped and covered.

[0037] By adopting the technical scheme, the composite shielding layer forms a multi-layer shielding structure of electric-magnetic-electric-magnetic-electric, and a closed magnetic circuit is formed therein. The magnetic coupling effect between the oppositely arranged magnetic conductive plating layers can effectively enhance the absorption and dissipation capacity of the composite shielding layer to low-frequency magnetic field, thereby further improving the shielding effect of the electromagnetic shielding cable.

[0038] To sum up, the technical scheme of the present application has at least one of the following beneficial effects:

[0039] 1. By arranging the composite magnetic conductive film with the magnetic conductive plating layer on the inner and outer sides of the braided layer, the composite shielding layer formed has more excellent shielding performance and a wider shielding frequency spectrum, which is conducive to improving the comprehensive shielding effect of the electromagnetic shielding cable, so that the electromagnetic shielding cable can shield most of the high-frequency and low-frequency electromagnetic interference.

[0040] 2. By using polyetherimide to prepare the film substrate of the composite magnetic conductive film together with specific ammonia-conductive fillers, the composite magnetic conductive film has excellent electrical conductivity, which is conducive to improving the shielding performance of the composite shielding layer, and has good mechanical properties, which is conducive to improving the durability of the composite shielding layer, thereby prolonging the service life of the electromagnetic shielding cable.

[0041] 3. By adding multi-walled carbon nanotubes, nano-copper powder and nano-nickel powder as nano-conductive fillers into the composite magnetic conductive film according to a specific proportion, a composite magnetic conductive film with excellent comprehensive electromagnetic shielding performance can be prepared.

[0042] 4. By arranging the magnetic conductive plating layer on one side of the magnetic conductive film and oppositely arranging the magnetic conductive plating layers of the composite magnetic conductive film when winding and coating the first film layer and the second film layer, the electromagnetic shielding efficiency of the braided layer can be improved, and the absorption and dissipation capacity of the composite shielding layer to low-frequency magnetic field can be enhanced. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 is a transverse sectional view of a composite magnetic conductive film in Preparation Example 2-1 of the present application.

[0044] Figure 2 is a transverse sectional view of an electromagnetic shielding cable in Example 1 of the present application.

[0045] Figure 3 is Figure 2 is a partial enlarged view of a in

[0046] Figure 4 is a transverse sectional view of an electromagnetic shielding cable in Example 8 of the present application.

[0047] Figure 5is a lateral sectional partial enlarged view of a electromagnetic shielding cable diagram in embodiment 9 of the present application.

[0048] Explanation of reference numerals:

[0049] 1, composite magnetic conductive film; 11, film substrate; 12, magnetic conductive plating layer; 2, bundled cable core; 3, inner insulation layer; 4, composite shielding layer; 41, first film layer; 42, braided layer; 43, second film layer; 5, outer insulation layer. DETAILED DESCRIPTION

[0050] The present application is further described in detail below with reference to the accompanying drawings. Figures 1-5 , Preparation Examples, Examples, and Comparative Examples.

[0051] The nano-carbon powder, multi-walled carbon nanotubes, and nano-metal powder are all purchased from Beijing Dekedaojin Technology Co., Ltd. The average particle size of the purchased nano-carbon powder is 40 nm, the specific model of the multi-walled carbon nanotubes is CNT105, and the average particle size of the purchased nano-metal powder is 50 nm.

[0052] The polyetherimide is purchased from SABIC, and the specific model is ULTEM 1000.

[0053] The iron-cobalt-chromium-nickel-manganese alloy is specifically purchased from Zhongke Yannuo.

[0054] Preparation Example

[0055]

Preparation Example 1-1

[0056] An ammoniated conductive filler is prepared from an amino-silane modified nano-conductive filler. Specifically, the ammoniated conductive filler is prepared by the following preparation method: 1 kg of nano-conductive filler is added to anhydrous ethanol at 20 wt%, and after being fully ultrasonically dispersed for 10 min, 0.2 kg of polyvinylpyrrolidone and 0.2 kg of γ-aminopropyltriethoxysilane are added, and the stirring reaction is continued for 30 min. After filtration and multiple washing with anhydrous ethanol, the ammoniated conductive filler is obtained after drying.

[0057] In the present preparation example, the nano-conductive filler is a mixture of nano-carbon powder and nano-copper powder, wherein the mixing mass ratio of the nano-carbon powder to the nano-copper powder is 2:8, i.e., including 0.2 kg of nano-carbon powder and 0.8 kg of nano-copper powder.

[0058]

Preparation Example 1-2

[0059] An amino-conductive filler is prepared by modifying a nano-conductive filler with an amino-silane. Specifically, the amino-conductive filler is prepared by adding 1 kg of nano-conductive filler to anhydrous ethanol at 20 wt%, ultrasonically dispersing for 10 min, adding 0.1 kg of polyvinylpyrrolidone and 0.3 kg of γ-aminopropyl triethoxysilane, continuously stirring for 30 min, filtering, washing with anhydrous ethanol multiple times, and drying to obtain the amino-conductive filler.

[0060] In this preparation example, the nano-conductive filler is a mixture of nano-carbon powder and nano-copper powder, wherein the mixing mass ratio of the nano-carbon powder to the nano-copper powder is 3:7, i.e., including 0.3 kg of nano-carbon powder and 0.7 kg of nano-copper powder.

[0061]

Preparation Example 1-3

[0062] An amino-conductive filler, which is different from that of

Preparation Example 1-1

[0063] In this preparation example, the nano-conductive filler is a mixture of multi-walled carbon nanotubes and nano-copper powder, wherein the mixing mass ratio of the multi-walled carbon nanotubes to the nano-copper powder is 2:8, i.e., including 0.2 kg of multi-walled carbon nanotubes and 0.8 kg of nano-copper powder.

[0064]

Preparation Example 1-4

[0065] An amino-conductive filler, which is different from that of

Preparation Example 1-3

[0066] In this preparation example, the nano-conductive filler is a mixture of multi-walled carbon nanotubes, nano-copper powder, and nano-nickel powder, wherein the mixing mass ratio of the multi-walled carbon nanotubes, the nano-copper powder, and the nano-nickel powder is 2:6:2, i.e., including 0.2 kg of multi-walled carbon nanotubes, 0.6 kg of nano-copper powder, and 0.2 kg of nano-nickel powder.

[0067]

Preparation Example 1-5

[0068] An amino-conductive filler, which is different from that of

Preparation Example 1-3

[0069] In this preparation example, the nano-conductive filler is a mixture of multi-walled carbon nanotubes, nano-copper powder, and nano-nickel powder, wherein the mixing mass ratio of the multi-walled carbon nanotubes, the nano-copper powder, and the nano-nickel powder is 2:7.5:0.5, i.e., including 0.2 kg of multi-walled carbon nanotubes, 0.75 kg of nano-copper powder, and 0.05 kg of nano-nickel powder.

[0070]

Preparation Example 2-1

[0071] A composite magnetic-conductive film 1, with reference to Figure 1, including a thin film base material 11 and a magnetically conductive plating layer 12 arranged on one side of the thin film base material 11.

[0072] Specifically, the thin film base material 11 is made of the following raw materials:

[0073] 10 kg of polyetherimide, 0.2 kg of ammoniated conductive filler, and 1.2 kg of sodium dodecyl sulfonate.

[0074] In this preparation example, the ammoniated conductive filler is specifically selected from the ammoniated conductive filler prepared in

Preparation Example 1-1

[0075] A method for preparing a composite magnetically conductive film 1, comprising the following steps:

[0076] A1, dissolve 10wt% of polyetherimide in N-methylpyrrolidone, heat in water bath to 65℃ and continuously stir for 12h, so that it is fully dissolved and dispersed, add sodium dodecyl sulfonate, keep the temperature and continuously stir until fully dissolved, add ammoniated conductive filler, continuously stir and disperse, then perform ultrasonic dispersion treatment for not less than 3 times, each time for 20min, prepare a spinning solution, perform electrospinning, after spinning is completed, put into a 60℃ air oven for low temperature drying, get a thin film base material 11 with a thickness of 0.2mm;

[0077] A2, take the thin film base material 11 prepared in S1 into a vacuum magnetization sputtering coating system, use iron-cobalt-chromium-nickel-manganese alloy as target material, keep the vacuum degree less than 1.5×10 -3 Pa, heat to 230℃, pass in argon at a flow rate of 1000sccm, set the sputtering power to 80W, the target-substrate distance to 90mm, continuously sputter for 10min, after the iron-cobalt-chromium-nickel-manganese alloy is uniformly deposited on one side surface of the thin film base material 11, form a magnetically conductive plating layer 12 with a thickness of 150μm, get a composite magnetically conductive film 1.

[0078]

Preparation Example 2-2

[0079] A composite magnetically conductive film 1, which is different from

Preparation Example 1-1

[0080] Specifically, the thin film base material 11 is made of the following raw materials:

[0081] 10 kg of polyetherimide, 0.1 kg of ammoniated conductive filler, and 0.8 kg of sodium dodecyl sulfonate.

[0082] In this preparation example, the ammoniated conductive filler is specifically selected from the ammoniated conductive filler prepared in

Preparation Example 1-2

[0083] A method for preparing a composite magnetically conductive film 1, comprising the following steps:

[0084] A1, the polyetherimide is dissolved in N-methylpyrrolidone at 20wt%, heated in a water bath to 60℃ and continuously stirred for 12h to make it fully dissolved and dispersed, sodium dodecyl sulfonate is added, the temperature is maintained and continuously stirred until fully dissolved, ammonia-conductive filler is added, continuously stirred and dispersed, and then ultrasonic dispersion treatment is carried out for 3 times, each for 30min, to prepare a spinning solution, electrospinning is carried out, and after spinning is completed, it is placed in a 60℃ forced air oven for low-temperature drying to obtain a thin film substrate 11 with a thickness of 0.3mm;

[0085] A2, the thin film substrate 11 prepared in S1 is sent into a vacuum magnetized sputtering film coating system, iron-cobalt-chromium-nickel-manganese alloy is used as target material, the vacuum degree is maintained to be less than 1.5×10-3Pa, heated to 180℃, argon gas is introduced at a flow rate of 1000sccm, the sputtering power is set to 120W, the target-substrate distance is 90mm, and sputtering is continuously carried out for 5min, so that the iron-cobalt-chromium-nickel-manganese alloy is uniformly deposited on one side surface of the thin film substrate 11 to form a magnetically conductive plating layer 12 with a thickness of 100μm, and a composite magnetically conductive thin film 1 is obtained.

[0086]

Preparation Example 2-3

[0087] A composite magnetically conductive thin film 1, which is different from

Preparation Example 1-1

[0088] In this preparation example, the ammonia-conductive filler in the thin film substrate 11 is specifically selected from an ammonia-conductive filler prepared in

Preparation Example 1-3

[0089]

Preparation Example 2-4

[0090] A composite magnetically conductive thin film 1, which is different from

Preparation Example 1-1

[0091] In this preparation example, the ammonia-conductive filler in the thin film substrate 11 is specifically selected from an ammonia-conductive filler prepared in

Preparation Example 1-4

[0092]

Preparation Example 2-5

[0093] A composite magnetically conductive thin film 1, which is different from

Preparation Example 1-1

[0094] In this preparation example, the ammonia-conductive filler in the thin film substrate 11 is specifically selected from an ammonia-conductive filler prepared in

Preparation Example 1-5

[0095]

Preparation Example 2-6

[0096] A composite thin film, which is different from

Preparation Example 1-1

[0097] Preparation Example 2-7

[0098] A composite film, which is different from the preparation example 1-1 in that the raw material of the film substrate 11 is different.

[0099] In this preparation example, the film substrate 11 is made of the following raw materials by weight: 10 kg of polyetherimide, 0.1 kg of nano-conductive filler without ammonia modification, and 0.8 kg of sodium dodecyl sulfonate.

[0100] Among them, the nano-conductive filler without ammonia modification includes 0.02 kg of nano-carbon powder and 0.08 kg of nano-copper powder.

[0101] Example

[0102] Example 1

[0103] An electromagnetic shielding cable, referring to Figure 2 and Figure 3 , comprising a bundled cable core 2, an inner insulating layer 3, a composite shielding layer 4 and an outer insulating layer 5 arranged in order from inside to outside, wherein the composite shielding layer 4 comprises a first film layer 41, a braided layer 42 and a second film layer 43 arranged in order from inside to outside.

[0104] In this example, the braided layer 42 is woven with tin-plated copper strips, and the first film layer 41 and the second film layer 43 are both wrapped and coated with a composite magnetic film 1 prepared by the preparation example 2-1.

[0105] A preparation method of an electromagnetic shielding cable, comprising the following steps:

[0106] S1, first prepare the bundled cable core 2 and the inner insulating layer 3, wrap and coat the composite magnetic film 1 on the outer peripheral side of the inner insulating layer 3 to form the first film layer 41; wherein the magnetic conductive plating layer 12 of the composite magnetic film 1 is located on the side away from the inner insulating tube, and the number of wrapping and coating layers is 3;

[0107] S2, using tin-plated copper strips to braid on the outer peripheral side of the first film layer 41 at a braiding angle of 30° to form the braided layer 42;

[0108] S3, wrap and coat the composite magnetic film 1 again on the outer peripheral side of the braided layer 42 to form the second film layer 43; wherein the magnetic conductive plating layer 12 of the composite magnetic film 1 is located on the side towards the braided layer 42, and the number of wrapping and coating layers is 3;

[0109] S4, prepare the outer insulating layer 5 to coat on the outer peripheral side of the second braided layer 42 to obtain an electromagnetic shielding cable.

[0110] Example 2

[0111] An electromagnetic shielded cable, which differs from

Embodiment 1

[0112] In this embodiment, the braided layer 42 is braided with nickel-plated carbon fibers, and the first film layer 41 and the second film layer 43 are each wrapped with a composite magnetic conductive film 1 prepared in

Preparation Example 2-2

[0113]

Embodiment 3

[0114] An electromagnetic shielded cable, which differs from

Embodiment 1

[0115] In this embodiment, the first film layer 41 and the second film layer 43 are each wrapped with a composite magnetic conductive film 1 prepared in

Preparation Example 2-3

[0116]

Embodiment 4

[0117] An electromagnetic shielded cable, which differs from

Embodiment 3

[0118] In this embodiment, the first film layer 41 and the second film layer 43 are each wrapped with a composite magnetic conductive film 1 prepared in

Preparation Example 2-4

[0119]

Embodiment 5

[0120] An electromagnetic shielded cable, which differs from

Embodiment 3

[0121] In this embodiment, the first film layer 41 and the second film layer 43 are each wrapped with a composite magnetic conductive film 1 prepared in

Preparation Example 2-5

[0122]

Embodiment 6

[0123] An electromagnetic shielded cable, which differs from

Embodiment 5

[0124] In this embodiment, the braided layer 42 is braided with nickel-plated carbon fibers.

[0125]

Embodiment 7

[0126] An electromagnetic shielded cable, which differs from

Embodiment 5

[0127] In this embodiment, the braided layer 42 is braided with silver-plated aramid fibers.

[0128]

Embodiment 8

[0129] An electromagnetic shielded cable, which differs from

Embodiment 5

[0130] In the present embodiment, referring to Figure 4 , the magnetically conductive plating layer 12 of the composite magnetically conductive film 1 of the first film layer 41 is located on the side facing away from the inner insulating tube; the magnetically conductive plating layer 12 of the composite magnetically conductive film 1 of the second film layer 43 is located on the side facing away from the braided layer 42, i.e. the same direction.

[0131]

Example 9

[0132] An electromagnetic shielding cable, which differs from

Example 5

[0133] In the present embodiment, referring to Figure 5 , the magnetically conductive plating layer 12 of the composite magnetically conductive film 1 of the first film layer 41 is located on the side facing away from the inner insulating tube; the magnetically conductive plating layer 12 of the composite magnetically conductive film 1 of the second film layer 43 is located on the side facing away from the braided layer 42, i.e. the same direction.

[0134] Comparative Example

[0135]

Comparative Example 1

[0136] A cable, which differs from

Example 1

[0137] In the present comparative example, the composite shielding layer 4 is only provided with a braided layer 42, specifically, the braided layer 42 is woven with a tin-plated copper strip.

[0138]

Comparative Example 2

[0139] A cable, which differs from

Example 1

[0140] In the present comparative example, the first film layer 41 and the second film layer 43 in the composite shielding layer 4 are both wound and coated with a composite film prepared in

Preparation Example 2-6

[0141]

Comparative Example 3

[0142] A cable, which differs from

Example 1

[0143] In the present comparative example, the first film layer 41 and the second film layer 43 in the composite shielding layer 4 are both wound and coated with a composite film prepared in

Preparation Example 2-7

[0144] Performance detection data

[0145] 1. High and low frequency electromagnetic shielding performance: first, according to the cable structure of each example and the comparative example, the first film layer, the braided layer and the second film layer are laid flat and formed into a flat plate structure to obtain a test plate, and then the high frequency and low frequency electromagnetic shielding performance is measured according to GB / T 30142-2013 "Method for measuring the shielding effectiveness of planar electromagnetic shielding materials", wherein the shielding chamber method is used for measurement, the magnetic field shielding and electric field shielding are measured in the frequency range of 10 kHz-30 MHz, the electric field shielding is measured in the frequency range of 30 MHz-1 GHz, and at least 10 frequency points are randomly selected in each range for testing. If the maximum difference of electromagnetic shielding effectiveness measured in 10 frequency points is ≤10 dB, the average value of electromagnetic shielding effectiveness (dB) in the range is calculated and recorded; if the maximum difference of electromagnetic shielding effectiveness measured in 10 frequency points is >10 dB, the maximum value and the minimum value are taken as the end points, and the electromagnetic shielding effectiveness range value (dB) in the frequency range is recorded.

[0146] 2. Tensile properties of composite magnetic conductive film: the composite magnetic conductive film is tested according to GB / T 1040.3-2006 "Determination of tensile properties of plastics-Part 3: test conditions for films and sheets", and the tensile strength (MPa) of the composite magnetic conductive film used in each example and the comparative example is recorded.

[0147] Table 1 High and low frequency electromagnetic shielding performance of cable

[0148]

[0149] According to the data in Example 1 and Comparative Examples 1-2 and Table 1, the composite shielding layer 4 formed by coating the composite magnetic conductive film 1 with a magnetic conductive plating layer 12 on the inner and outer sides of the braided layer 42 has more excellent shielding performance and a wider shielding spectrum than the traditional conductive braided layer 42, not only has high shielding effectiveness for high frequency electric field, but also has high shielding effectiveness for low frequency magnetic field and low frequency electric field, which is beneficial to improve the comprehensive shielding effect of the electromagnetic shielding cable, and most of the high frequency and low frequency electromagnetic interference can be shielded by the electromagnetic shielding cable.

[0150] The comparative example 1 and the comparative example 2 and the detection data thereof show that the thin film substrate 11 supported by the polyetherimide and the ammoniated conductive filler can effectively improve the shielding effectiveness of the composite shielding layer 4 to the high-frequency electric field and the low-frequency electric field, but the shielding effectiveness to the low-frequency magnetic field is not greatly improved. The comparative example 1 and the comparative example 2 and the detection data thereof show that the magnetic conductive plating layer 12 formed by the iron-cobalt alloy can effectively improve the low-frequency magnetic field shielding effectiveness of the composite shielding layer 4, and can also slightly improve the high-frequency electric field shielding effectiveness. This may be because the composite magnetic conductive film 1 coated on the inside and outside of the woven layer 42 can form a uniform and dense conductive network with the conductive woven layer 42, which can effectively reflect and absorb the high-frequency electric field in the high-frequency range, and reduce the penetration of the high-frequency electric wave. In the low-frequency range, the dense conductive network can guide and dissipate the low-frequency electric field well. At the same time, since the magnetic conductive plating layer 12 is deposited by the iron-cobalt alloy with high magnetic conductive efficiency, it can provide a low magnetic resistance path, thereby "attracting" the external low-frequency magnetic field into the film, reducing the penetration of the low-frequency magnetic field through the composite shielding layer 4, and improving the low-frequency magnetic field shielding effectiveness. In addition, the magnetic conductive plating layer 12 can also produce a multi-layer synergistic effect of enhancing the magnetic field gradient between the first film layer 41 and the second film layer 43, which can indirectly improve the eddy current effect of the conductive woven layer 42 in the alternating magnetic field, and further improve the electromagnetic shielding effectiveness of the woven layer 42.

[0151] The data in Table 1 show that the use of amino silane and polyvinylpyrrolidone to modify the surface of the nano conductive filler can improve the high and low frequency shielding effectiveness and mechanical properties of the composite magnetic conductive film 1. This may be because the surface of the selected nano filler is too high, which makes it difficult to disperse in the polyetherimide solution, and also easy to cause powder agglomeration, resulting in poor shielding performance and mechanical properties of the composite magnetic conductive film 1. However, after treatment, the amino silane improves the surface properties of the filler through chemical bonding, and the polyvinylpyrrolidone provides additional dispersion stability through physical adsorption, thereby forming a more uniform and continuous conductive network and structure network in the composite magnetic conductive film 1 through the synergistic effect of the two, and improving the shielding effectiveness and mechanical properties of the composite magnetic conductive film 1.

[0152] The data in Table 1 show that the use of multi-walled carbon nanotubes to replace an equal amount of nano carbon powder can further improve the high and low frequency electric field shielding effectiveness of the composite shielding layer 4, and further improve the mechanical strength of the composite magnetic conductive film 1. This may be because the multi-walled carbon nanotubes have a higher aspect ratio than the randomly dispersed nano carbon powder, which can form a dense network on the surface of the polyetherimide film and wrap around a small amount of fiber surface, thereby further improving the electrical conductivity and mechanical properties of the composite magnetic conductive film 1.

[0153] In addition, a small amount of nano-nickel powder is used to replace nano-copper powder, which can effectively improve the low-frequency magnetic field shielding performance of the composite magnetic conductive film 1, and has little effect on the shielding performance of high-frequency electric field and low-frequency electric field. However, as the content of nickel powder continues to increase, the low-frequency magnetic field shielding performance of the composite magnetic conductive film 1 is not greatly improved, and the shielding performance of high-frequency electric field and low-frequency electric field is greatly negatively affected. This may be because nano-nickel powder has high magnetic permeability, and a small amount of addition will not significantly reduce the electrical conductivity of the composite magnetic conductive film 1, but can significantly reduce the magnetic resistance of the film substrate 11, thereby enhancing the low-frequency magnetic field shielding performance of the composite magnetic conductive film 1. However, when the content of nickel powder exceeds a certain threshold, the magnetic permeability of the composite material tends to be saturated, and the electrical conductivity of the nano-nickel powder is poor, which can destroy the original conductive network, resulting in a decrease in the electrical conductivity of the composite magnetic conductive film 1, and thus the shielding performance of high-frequency electric field and low-frequency electric field is significantly reduced.

[0154] According to the data in Table 1 and in combination with Examples 5-7, when the braided layer 42 is braided with nickel-plated carbon fibers, compared with the conventional tin-plated copper tape, the low-frequency magnetic field shielding performance of the composite shielding layer 4 formed thereby is improved, and the high-frequency electric field shielding performance is reduced. This may be because the electrical conductivity of the nickel-plated carbon fiber is poorer than that of the tin-plated copper tape, and the magnetic conductivity is better, which is more suitable for low-frequency magnetic field shielding. When the braided layer 42 is braided with silver-plated aramid fiber, the composite shielding layer 4 formed thereby has higher high-frequency electric field shielding performance and lower low-frequency magnetic field shielding performance. This may be because the electrical conductivity of the silver-plated aramid fiber is better, and the magnetic conductivity is almost the same as that of the tin-plated copper tape, thereby showing better high-frequency electric field shielding performance. In addition, since the densities of the nickel-plated carbon fiber and the silver-plated aramid fiber are both lower than that of the tin-plated copper tape, when the nickel-plated carbon fiber and the silver-plated aramid fiber are used as the braided layer 42, the overall weight of the composite shielding layer 4 can be reduced, which is conducive to the lightweight of the electromagnetic shielding cable.

[0155] According to the data in Table 1 and in combination with Examples 5, 8-9, when the magnetic conductive plating layers 12 of the first film layer 41 and the second film layer 43 are arranged opposite to each other, the low-frequency magnetic field shielding performance of the composite shielding layer 4 is better than that when the magnetic conductive plating layers 12 are arranged in the same direction or opposite to each other. This may be because when the magnetic conductive plating layers 12 of the first film layer 41 and the second film layer 43 are arranged opposite to each other, the composite shielding layer 4 forms a multi-layer shielding structure of electric-magnetic-electric-magnetic-electric, and forms a closed magnetic circuit, which can produce a magnetic coupling effect, enhance the absorption and dissipation capacity of the composite shielding layer 4 to low-frequency magnetic field, and further improve the shielding performance.

[0156] The specific embodiment is only an explanation of the present application, which is not a limitation of the present application. Those skilled in the art can make modifications to the specific embodiment without creative contribution after reading the present specification, but as long as the modifications are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. An electromagnetic shielded cable, characterized by: The cable includes a bundle cable core (2), an inner insulation layer (3), a composite shielding layer (4) and an outer insulation layer (5) arranged in sequence from inside to outside, and the composite shielding layer (4) includes a first film layer (41), a braided layer (42) and a second film layer (43) arranged in sequence from inside to outside. The braided layer (42) is made of conductive fibers. The first film layer (41) and the second film layer (43) are both made of a composite magnetic film (1) which is wound and coated, and the composite magnetic film (1) includes a film base material (11) and a magnetic plating layer (12), wherein the film base material (11) of the composite magnetic film (1) is prepared from polyetherimide and ammoniated conductive filler, and the magnetic plating layer (12) is deposited on one side surface of the film base material (11) from an iron-cobalt alloy. The film base material (11) of the composite magnetic film (1) includes the following raw materials by weight: Polyetherimide: 100 parts; Ammoniated conductive filler: 1-2 parts; Sodium dodecyl sulfonate: 8-12 parts; The ammoniated conductive filler is prepared from amino silane modified nano conductive filler, and the nano conductive filler is a mixture of one of nano carbon powder or multi-walled carbon nanotubes and nano metal powder. The preparation method of the ammoniated conductive filler includes the following steps: The nano conductive filler is added to anhydrous ethanol, ultrasonically dispersed, then polyvinylpyrrolidone and gamma-aminopropyl triethoxysilane are added, continuous stirring reaction is performed, filtration and multiple cleaning with anhydrous ethanol are performed, and drying is performed to obtain the ammoniated conductive filler.

2. The electromagnetic shielding cable of claim 1, wherein: The mixing mass ratio of the nano conductive filler, the polyvinylpyrrolidone and the gamma-aminopropyl triethoxysilane is 10:(1-2):(2-3).

3. The electromagnetic shielding cable of claim 1, wherein: The nano conductive filler is a mixed powder of multi-walled carbon nanotubes, nano copper powder and nano nickel powder, and the mixing mass ratio of the multi-walled carbon nanotubes, the nano copper powder and the nano nickel powder is (2-3):(6-7.5):(0.5-2).

4. The electromagnetic shielding cable of claim 1, wherein: The preparation method of the composite magnetic film (1) includes the following steps: A1, polyetherimide is dissolved in N-methylpyrrolidone at 10-20wt%, heated to 60-65℃ in water bath and continuously stirred for not less than 12h, so as to be fully dissolved and dispersed, sodium dodecyl sulfonate is added, the temperature is kept and continuously stirred until fully dissolved, ammoniated conductive filler is added, continuously stirred and dispersed, then ultrasonic dispersion treatment is performed for not less than 3 times, each time for 20-30min, a spinning solution is prepared, electrospinning is performed, low-temperature drying is performed after spinning is completed, and the film base material (11) is obtained; A2, the film base material (11) prepared in S1 is sent into a vacuum magnetization sputtering coating system, an iron-cobalt alloy is used as target material, the vacuum degree is kept less than 1.5×10-3Pa, heated to 180-230℃, argon is introduced, the sputtering power is set to 80-120W, and sputtering is continuously performed for 5-10min, until the iron-cobalt alloy is uniformly deposited on one side surface of the film base material (11) to form a magnetic plating layer (12), and a composite magnetic film (1) is obtained.

5. An electromagnetic shielded cable according to claim 4, characterized in that: The thickness of the film base material (11) is 0.2-0.3mm, and the thickness of the magnetically conductive plating layer (12) is 100-150nm.

6. A method for the production of an electromagnetic shielded cable for the production of an electromagnetic shielded cable according to any one of claims 1 to 5, characterized in that The method comprises the following steps: S1, a bundle cable core (2) and an inner insulation layer (3) are prepared in sequence, the composite magnetically conductive film (1) is wound and coated on the outer circumferential side of the inner insulation layer (3) to form a first film layer (41); S2, a conductive fiber is used to weave on the outer circumferential side of the first film layer (41) to form a woven layer (42); S3, the composite magnetically conductive film (1) is wound and coated again on the outer circumferential side of the woven layer (42) to form a second film layer (43); S4, an outer insulation layer (5) is prepared to coat on the outer circumferential side of the second woven layer (42) to obtain an electromagnetic shielding cable.

7. A method of manufacturing an electromagnetic shielding cable according to claim 6, characterized in that: The conductive fiber is one of a nickel-plated carbon fiber or a silver-plated aramid fiber.

8. A method of making an electromagnetic shielding cable according to claim 6, characterized in that: In steps S1 and S3, when the composite magnetically conductive film (1) is wound and coated, the magnetically conductive plating layer (12) is always directed to one side of the woven layer (42).

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