Flexible magnetic shielding fiber and preparation method thereof

Abstract

The invention belongs to the field of electromagnetic materials, and particularly relates to a flexible magnetic shielding fiber which comprises a core material and a metal wire spirally wound on the outer circumferential surface of the core material. The core material is a polymer fiber material; the metal wires are formed by chemically plating coatings on the surfaces of permalloy fibers; a plating solution for surface chemical plating comprises the following components: an iron-containing compound, a nickel-containing compound, a reducing agent, a complexing agent and a pH value regulator. The fabric prepared from the magnetic field shielding fiber has the advantage of flexibility and also has good low-frequency and magnetic field shielding performance. The invention also provides a preparation method of the flexible magnetic shielding fiber.

Description

Technical Field

[0001] The invention belongs to the field of electromagnetic materials, and in particular relates to a flexible magnetic shielding fiber and a preparation method thereof. Background Art

[0002] Magnetic shielding is a technology that limits magnetic fields to a specific area. It plays an important role in electronic equipment and communication systems. Permalloy, as a commonly used magnetic shielding material, has excellent magnetic shielding effects and is widely used in various fields.

[0003] Permalloy, also known as iron-nickel alloy, is an alloy with a nickel content between 35% and 90%, which has the characteristics of high conductivity and high magnetic permeability. This enables Permalloy to effectively absorb electromagnetic waves and shield external magnetic fields to avoid interference with the surrounding environment and equipment.

[0004] In addition, since Permalloy is a metal alloy material, it is conventionally made into metal sheets to prepare shielding bodies. However, due to the relatively poor plasticity and mechanical properties of metal sheets, large-sized and thin materials cannot be prepared, and the application requirements of some special occasions cannot be met.

[0005] In order to solve the problem of poor plasticity of metal materials and the preparation of large-sized and thin materials, the prior art makes Permalloy into fibers and further makes them into fabrics to achieve their flexibility. However, in the process of making Permalloy into fiber filaments, it is necessary to draw Permalloy in a copper tube and other operations. Although it will go through the copper removal process later, it is inevitable that a lot of copper will remain on the surface of the Permalloy fiber filaments, which will increase the conductivity of the prepared Permalloy fiber filaments and reduce the magnetic permeability, further reducing the magnetic field shielding performance of the prepared fabric.

[0006] Based on this, it is necessary to develop a flexible magnetic shielding fiber with excellent magnetic field shielding performance. Summary of the invention

[0007] The first purpose of the present invention is to provide a flexible magnetic shielding fiber, the fabric prepared by the flexible fiber has excellent low-frequency and magnetic field shielding performance while having the advantage of flexibility.

[0008] The second object of the present invention is to provide a method for preparing the above-mentioned flexible magnetic shielding fiber, which can simply and efficiently prepare the above-mentioned magnetic shielding fiber.

[0009] In order to achieve the above object, the present invention provides the following specific solutions:

[0010] A flexible magnetic shielding fiber comprises a core material and a metal wire spirally wound on the outer circumference of the core material; the core material is a polymer fiber material; the metal wire is formed by chemically plating a Permalloy fiber wire surface; the surface chemical plating solution comprises the following components: an iron-containing compound, a nickel-containing compound, a reducing agent, a complexing agent and a pH value regulator.

[0011] The present invention provides an effective coating layer on the surface of the Permalloy fiber wire by chemically plating an iron-nickel alloy liquid on the surface of the Permalloy fiber wire, so that the copper remaining in the Permalloy fiber wire during the preparation process is effectively coated by the coating layer, thereby avoiding the problem of enhanced conductivity and decreased magnetic conductivity caused by the presence of copper.

[0012] In addition, the present invention sets a polymer fiber material as a core material, and spirally winds a plated metal wire outside the core material. Through the use of the polymer core material, the strength and toughness of the obtained fiber are effectively improved, thereby improving its application stability.

[0013] Moreover, the fibers formed by spirally winding metal wires on the surface of the core material have a three-dimensional structure. After forming a fabric, the shielding performance of the shielding body can be enhanced through the anisotropic and multi-directional magnetic and electrical losses of the three-dimensional structure. At the same time, since the fabric is cross-woven with fiber filaments with a spiral winding structure, the entire fabric can be regarded as composed of countless spiral structures. For each spiral tube, it can be regarded as a micro-coil, and the influence of the external electromagnetic field can be regarded as two micro-bodies with induced currents and spiral tubes generating reverse magnetic fields. In this way, the magnetic field inside the spiral tube is zero, and a large-area fabric composed of countless such micro-bodies can achieve an excellent shielding effect.

[0014] Preferably, the core material is selected from aramid or polyester fibers.

[0015] Preferably, the metal wire is wound in two layers on the outer circumference of the core material, and the winding directions of the two layers of metal wire are opposite.

[0016] Through the double-layer metal wire, the shielding sealing of the entire fiber wire can be further guaranteed.

[0017] Preferably, the pitch of the spiral winding of the metal wire on the outer circumference of the core material is the diameter of the metal wire.

[0018] During the wire winding process, the pitch of the spiral of the wire wound on the outer circumference of the core material is the diameter of the wire, that is, adjacent spiral tubes are tightly fitted, further ensuring the shielding sealing of the entire fiber filament.

[0019] Preferably, the plating solution also contains rare earth nanomaterials.

[0020] Further preferably, the rare earth nanomaterial is selected from one or more of nano-La2O3, nano-CeO2 or nano-Y2O3.

[0021] By introducing rare earth nanomaterials into the plating solution, they are co-precipitated with Ni and Fe on the surface of Permalloy fibers. The introduction of rare earth elements can enhance the magnetocrystalline anisotropy field of the crystal and greatly increase the resistance to domain wall displacement, which is beneficial to the improvement of the hysteresis loss of the material and greatly improves the magnetic permeability. At the same time, it can enhance the material's attenuation ability for electromagnetic waves, so that the material can achieve absorption as the main and reflection as the auxiliary for electromagnetic waves.

[0022] Preferably, the reducing agent is sodium borohydride, the complexing agent is potassium sodium tartrate, and the pH adjusting agent is ammonia water.

[0023] Further preferably, the plating solution for surface chemical plating includes the following components: 18-25 g / L ammonium ferrous sulfate hexahydrate, 25-50 g / L nickel sulfate heptahydrate, 3-6 g / L sodium borohydride, 60-90 g / L potassium sodium tartrate, 5-20 g / L ammonia water, and 2-10 g / L rare earth nanomaterials.

[0024] Further preferably, the ratio of iron to nickel in the surface chemical plating solution is the same as the ratio of iron to nickel in the Permalloy fiber filament.

[0025] The present invention also provides a method for preparing the above-mentioned flexible magnetic shielding fiber, which is characterized by comprising the following steps:

[0026] S1. Configuring a surface chemical plating solution: configuring a surface chemical plating solution according to the content ratio of each component;

[0027] S2. Preparation of metal wire: preparing metal wire by chemical plating on the surface of Permalloy fiber wire;

[0028] S3. Preparation of shielding fiber: The shielding fiber is prepared by spirally winding a metal wire on the surface of a core material.

[0029] Furthermore, in step S2, chemical plating on the surface of the Permalloy fiber is performed under ultrasonic vibration, the temperature of the chemical plating is 65-70° C., and the time is 20-30 min.

[0030] By controlling the temperature and time of chemical plating, the thickness of the surface chemical plating coating layer can be effectively controlled, so that materials can be saved as much as possible under the condition of effective coating.

[0031] The beneficial effects of the present invention are:

[0032] (1) The present invention solves the problem of low frequency and poor magnetic field shielding performance of Permalloy fiber wire caused by the introduction of copper by chemically plating iron-nickel alloy liquid on the surface of Permalloy fiber wire.

[0033] (2) The present invention improves the strength and toughness of the formed fibers by designing a method for introducing polymer fibers, thereby ensuring the strength and toughness of the fabric finally formed and improving the application adaptability and application stability of the fibers.

[0034] (3) The present invention further improves the low-frequency and magnetic field shielding performance of the fabric formed by the shielding fibers of the present invention by designing a three-dimensional structure formed by spirally winding a metal wire on the surface of a polymer fiber core material and a special micro-circle structure of the spiral tube.

[0035] (4) The present invention introduces rare earth nano-elements into the Permalloy fiber plating solution, thereby further improving the low-frequency and magnetic field shielding performance of the prepared shielding fiber. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a schematic diagram of the structure of the shielding fiber A prepared in Example 1;

[0037] Figure 2 This is a schematic diagram of the structure of the shielding fiber B prepared in Example 2;

[0038] Figure 3 This is the hysteresis loop diagram of the shielding fiber B prepared in Example 2;

[0039] Figure 4 This is the hysteresis loop diagram of Permalloy fiber E.

[0040] In the figure: 1-core material, 2-metal wire. DETAILED DESCRIPTION

[0041] To make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the present invention is further described below in conjunction with specific examples. In the embodiments, if the specific conditions are not indicated, the conditions are carried out according to normal conditions or manufacturer recommendations. The reagents used or the unindicated manufacturers are all conventional products that can be purchased commercially. All features disclosed in this specification, except mutually exclusive features and / or steps, can be combined in any way.

[0042] Example 1

[0043] This embodiment provides a method for preparing a flexible magnetic shielding fiber, which is characterized by comprising the following steps:

[0044] S1. Prepare a plating solution for surface chemical plating: prepare a plating solution for surface chemical plating according to the following content ratio of each component: 19.6 g / L ammonium ferrous sulfate hexahydrate, 30 g / L nickel sulfate heptahydrate, 4 g / L sodium borohydride, 75 g / L potassium sodium tartrate, 4 g / L rare earth nanomaterial, and add 10-12 g / L ammonia water to adjust the pH value to 9.0.

[0045] S2. Preparation of metal wire: The metal wire is prepared by chemical plating on the surface of the Permalloy fiber wire. A Permalloy fiber wire with a nickel content of 71% and a diameter of 0.012 mm is selected, and the plating solution of step S1 is used to chemically plate the surface thereof. The chemical plating is carried out under ultrasonic vibration at a temperature of 65° C. and a plating time of 30 min.

[0046] S3. Prepare shielding fiber: spirally wind the metal wire formed after plating in step S2 on the surface of 200D aramid fiber. In this embodiment, the metal wire is wound on the surface of the aramid fiber for one layer, and the shielding fiber formed is denoted as A, and its structure is as shown in the attached figure. Figure 1 As shown, a layer of metal wire 2 is spirally wound on the surface of the core material 1.

[0047] Example 2

[0048] This embodiment provides a method for preparing a flexible magnetic shielding fiber, which is characterized by comprising the following steps:

[0049] S1. Prepare a plating solution for surface chemical plating: prepare a plating solution for surface chemical plating according to the following content ratio of each component: 19.6 g / L ammonium ferrous sulfate hexahydrate, 30 g / L nickel sulfate heptahydrate, 4 g / L sodium borohydride, 75 g / L potassium sodium tartrate, 4 g / L rare earth nanomaterial, and add 10-12 g / L ammonia water to adjust the pH value to 9.0.

[0050] S2. Preparation of metal wire: The metal wire is prepared by chemical plating on the surface of the Permalloy fiber wire. A Permalloy fiber wire with a nickel content of 71% and a diameter of 0.012 mm is selected, and the plating solution of step S1 is used to chemically plate the surface thereof. The chemical plating is carried out under ultrasonic vibration at a temperature of 65° C. and a plating time of 30 min.

[0051] S3. Prepare shielding fiber: spirally wind the metal wire formed after plating in step S2 on the surface of aramid fiber with a diameter of 200D. In the embodiment, the metal wire is wound on the surface of aramid fiber in two layers, and the winding directions of the two layers of metal wire are opposite. The shielding fiber formed is denoted as B, and its structure is as shown in the attached figure. Figure 2 As shown, two layers of metal wire 2 are spirally wound on the surface of the core material 1.

[0052] Comparative Example 1

[0053] This comparative example provides a method for preparing a flexible magnetic shielding fiber, which is characterized by comprising the following steps:

[0054] A Permalloy fiber with a nickel content of 71% and a diameter of 0.012 mm is spirally wound on the surface of an aramid fiber with a diameter of 200D. The Permalloy fiber is wound on the surface of the aramid fiber in two layers, and the winding directions of the two layers of metal wire are opposite. The formed shielding fiber is recorded as C.

[0055] Comparative Example 2

[0056] This comparative example provides a method for preparing a flexible magnetic shielding fiber, which is characterized by comprising the following steps:

[0057] S1. Prepare a plating solution for surface chemical plating: prepare a plating solution for surface chemical plating according to the following content ratio of each component: 19.6 g / L ammonium ferrous sulfate hexahydrate, 30 g / L nickel sulfate heptahydrate, 4 g / L sodium borohydride, 75 g / L potassium sodium tartrate, 4 g / L rare earth nanomaterial, and add 10-12 g / L ammonia water to adjust the pH value to 9.0.

[0058] S2. Preparation of shielding fiber: A metal wire is prepared by chemical plating on the surface of a Permalloy fiber. A Permalloy fiber with a nickel content of 71% and a diameter of 0.012 mm is selected, and the plating solution of step S1 is used to perform chemical plating on the surface. The chemical plating is performed under ultrasonic vibration at a temperature of 65° C. and a plating time of 30 min. The prepared shielding fiber is denoted as D.

[0059] Experimental Example 1

[0060] The shielding fibers prepared in the above-mentioned Examples 1-2 and Comparative Examples 1-2 and the untreated Permalloy fiber yarn (referred to as Sample E) were respectively made into fabrics using a weaving machine. Specifically, a quiver loom was used to weave plain fabrics according to a warp density of 205 and a weft density of 205. The electromagnetic shielding effectiveness SE of the fabrics at different electromagnetic wave frequencies was tested. The results are as follows:

[0061] Table 1 Electromagnetic shielding effectiveness (dB) of fabrics prepared from various electromagnetic shielding fibers

[0062]

[0063] It can be seen from Table 1 that, compared with the Permalloy fiber filaments without any treatment, the Comparative Example 2 performs chemical plating on the surface of the Permalloy fiber filament, and the plating layer with the same composition as the Permalloy fiber can effectively improve the magnetic field shielding performance of the prepared shielding fiber at low frequency; it can be seen that the presence of the plating layer improves the problem of poor low-frequency and magnetic field shielding performance caused by the enhanced conductivity and reduced magnetic permeability caused by the residual copper in the Permalloy fiber processing process.

[0064] By comparing the electromagnetic shielding effectiveness of Example 1 and Example 2 with the Permalloy fiber, it can be seen that the shielding fiber formed by winding the plated metal wire around the surface of the aramid fiber has better shielding performance at low frequencies, and at the same time, the shielding performance at high frequencies can also be improved to a certain extent.

[0065] Experimental Example 2

[0066] The hysteresis loops of the shielded fiber B and the Permalloy fiber E prepared in Example 2 were tested using a JDAW-2000C&D vibrating sample magnetometer. The results are shown in the attached figure. Figure 3 and attached Figure 4 As shown, from Figure 3 and Figure 4 It can be seen from the comparison that the shielding fiber prepared in the present application has greatly improved the soft magnetic properties and has good magnetic permeability and large saturation magnetization intensity.

[0067] In summary, it can be seen that the shielding fiber prepared by the present invention achieves better low-frequency and magnetic field shielding performance.

[0068] The present invention is not limited to the above-mentioned embodiments, and anyone should be aware that any structural changes made under the enlightenment of the present invention, and any technical solutions that are the same or similar to the present invention, fall within the protection scope of the present invention.

Claims

1. A flexible magnetic shielding fiber, characterized in that: It comprises a core material and a metal wire spirally wound on the outer circumference of the core material; the core material is a polymer fiber material; the metal wire is formed by chemically plating a surface of a Permalloy fiber wire; The plating solution for surface chemical plating comprises the following components: an iron-containing compound, a nickel-containing compound, a reducing agent, a complexing agent and a pH value regulator.

2. The flexible magnetic shielding fiber according to claim 1, characterized in that: The core material is selected from aramid or polyester fibers.

3. The flexible magnetic shielding fiber according to claim 1, characterized in that: The metal wire is wound in two layers on the outer circumferential surface of the core material, and the winding directions of the two layers of the metal wire are opposite.

4. The flexible magnetic shielding fiber according to claim 3, characterized in that: The pitch of the spiral winding of the metal wire on the outer circumferential surface of the core material is the diameter of the metal wire.

5. The flexible magnetic shielding fiber according to claim 1, characterized in that: The plating solution also contains rare earth nanomaterials.

6. The flexible magnetic shielding fiber according to claim 5, characterized in that: The rare earth nanomaterial is selected from one or more of nano La2O3, nano CeO2 or nano Y2O3.

7. The flexible magnetic shielding fiber according to any one of claims 1 to 6, characterized in that: The reducing agent is sodium borohydride, the complexing agent is potassium sodium tartrate, and the pH value adjusting agent is ammonia water.

8. The flexible magnetic shielding fiber according to claim 7, characterized in that: The surface chemical plating solution comprises the following components: 18-25 g / L of ammonium ferrous sulfate hexahydrate, 25-50 g / L of nickel sulfate heptahydrate, 3-6 g / L of sodium borohydride, 60-90 g / L of potassium sodium tartrate, 5-20 g / L of ammonia water, and 2-10 g / L of rare earth nanomaterials.

9. The method for preparing the flexible magnetic shielding fiber according to any one of claims 1 to 8, characterized in that: The steps include: S1. Preparation of a surface chemical plating solution: a surface chemical plating solution is configured according to the content ratio of each component; S2. Preparation of metal wire: preparing metal wire by chemical plating on the surface of Permalloy fiber wire; S3. Preparing shielding fiber: The shielding fiber is prepared by spirally winding the metal wire on the surface of the core material.

10. The method for preparing the flexible magnetic shielding fiber according to claim 9, characterized in that: In step S2, chemical plating is performed on the surface of the Permalloy fiber under ultrasonic vibration, the temperature of the chemical plating is 65-70° C., and the time is 20-30 minutes.

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