Preparation method of flame-retardant magnetic wire rod and wire rod

Abstract

Rare earth iron nitrogen (R-Fe-N) magnetic powder is further compounded with ferrite magnetic powder, an elastic base material and a flame retardant are added to obtain a flame-retardant magnetic layer material, a wire core and the flame-retardant magnetic layer material are subjected to co-extrusion molding, and the wire is obtained through magnetization. And a wire preparation scheme with minimum addition of the flame retardant, highest magnetic attraction performance and optimal mechanical performance at present can be realized. The prepared wire rod has good flexibility and also has good tear resistance and tensile property, the excellent flame retardant property can still be kept under the condition that the adding amount of the flame retardant is reduced, and meanwhile the high magnetic attraction force of the wire rod is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of wires and their preparation, and in particular to a wire with a magnetic adsorption function and a flame retardant effect, which can be used in the fields of preparing data lines, power lines, signal lines, etc. Background Art

[0002] Wires including data cables, signal cables, power cables, etc. are widely used in the fields of home appliances and consumer electronics. For ease of use, wires used in the fields of consumer electronics and home appliances must have a certain length, usually more than 0.9m. How to store them conveniently is a common problem with traditional wires.

[0003] After the flexible bonded magnet is prepared by polymer compounds such as magnetic materials and elastomer materials, a magnetic field is generated in its orientation and / or magnetization direction, thereby generating a magnetic force of attraction between opposite poles. By utilizing the above characteristics of magnetic materials, the above flexible bonded magnet is added to the wire structure, which makes it possible to conveniently store the wire using suction. As countries have increasingly higher requirements for material safety and environmental protection, it has become a mandatory requirement for wires to achieve low-smoke flame retardancy, especially halogen-free low-smoke flame retardancy, especially in the field of home appliances and consumer electronics. Therefore, wires with magnetic adsorption function should also have flame retardant properties.

[0004] At present, the prior art discloses some technical solutions for magnetic wires. The invention patent with the authorization announcement number CN 113674921B - a method for preparing a magnetically attracted, automatically curled and freely stretched data cable discloses a magnetic wire, whose structure includes a flexible permanent magnetic coating layer in the middle, which is a flexible coating layer of a modified polymer composite material of permanent magnetic material samarium iron nitrogen magnetic powder, a binder and an additive. The median particle size D50 of the samarium iron nitrogen magnetic powder is 1 to 5 μm in the case of anisotropic samarium iron nitrogen magnetic powder, and 5 to 50 μm in the case of isotropic samarium iron nitrogen magnetic powder. The weight percentage of its permanent magnetic coating layer is: 85 to 93% of permanent magnetic material powder, 7 to 16% of binder, and 0 to 5% of processing aid. The permanent magnetic coating produced by this patent method does not have a flame retardant function, but proposes to add a flame retardant to the outer layer of the wire. According to the current flame retardant test standards, this is obviously difficult to achieve, or even impossible to achieve the flame retardant effect of the entire wire, and does not meet the safety standards of various countries. In addition, the D50 particle size of the anisotropic samarium iron nitrogen magnetic powder used in this patent is 1 to 5μm. However, when the D50 of the anisotropic samarium iron nitrogen magnetic powder is greater than 3μm, the magnetic properties of the anisotropic samarium iron nitrogen magnetic powder are low, the magnetic attraction of the wire is not high, and the mechanical properties are poor; and the magnetic attraction layer of this patent only uses samarium iron nitrogen magnetic powder, which is not conducive to achieving the optimal combination of flame retardant effect, magnetic attraction effect and mechanical properties. Furthermore, this patent does not achieve halogen-free, which does not meet the environmental protection requirements of some countries.

[0005] The utility model patent for data cable with the authorization announcement number CN 217036223 U discloses a data cable, in which the material of the sheath of the cable includes samarium iron nitrogen, and a heat-resistant shielding layer is set on the inner and outer sides of the middle sheath as a solution to the problem that samarium iron nitrogen is very easy to oxidize and burn, resulting in the overall flame retardancy of the cable being weak. It can be seen that the middle sheath of samarium iron nitrogen used in this patent has no flame retardant function and does not contain flame retardant materials. Furthermore, halogen-free is not mentioned.

[0006] It is a mandatory legal requirement for wires, especially data cables and charging cables, to be flame retardant. Magnetic powder materials, especially anisotropic samarium iron nitrogen magnetic powder, are submicron-sized magnetic powders. Based on its molecular formula (Sm2Fe 17 N3), the metal iron content is high and it is flammable. In order to ensure the magnetic effect and mechanical properties, too much flame retardant cannot be added. Therefore, achieving flame retardancy of magnetic wire is a difficult problem that must be solved. Summary of the invention

[0007] The object of the present invention is to provide a wire having magnetic adsorption and flame retardant functions and a preparation method thereof, so as to realize the convenient storage of wires such as data cables, signal cables, and power cables.

[0008] The first aspect of the present invention provides a method for preparing a flame-retardant magnetic wire, wherein the flame-retardant magnetic wire is provided with a wire core, a middle layer and an optional outer layer from the inside to the outside, wherein the middle layer is a flame-retardant magnetic layer, and the method for preparing the wire comprises:

[0009] (1) Extruding a wire core and a flame-retardant magnetic absorption layer material together to obtain a wire core coated with a flame-retardant magnetic absorption layer, wherein the flame-retardant magnetic absorption layer material comprises an elastic substrate, a magnetic material and a flame retardant; wherein the magnetic material comprises rare earth iron nitrogen magnetic powder, and further, the magnetic material comprises rare earth iron nitrogen magnetic powder and ferrite magnetic powder;

[0010] Optionally, an outer coating layer is prepared on the outer side of the obtained wire core coated with the flame-retardant magnetic absorption layer;

[0011] (2) shaping the wire obtained in step (1);

[0012] (3) magnetizing the wire obtained in step (2) to obtain the flame-retardant magnetic wire;

[0013] Furthermore, in the flame-retardant magnetic absorption layer material, the content of the elastic substrate is 15wt% to 25wt%, the content of the magnetic material is 55wt% to 75wt%, and the content of the flame retardant is 5wt% to 15wt%.

[0014] According to the method of the first aspect, the rare earth iron nitrogen magnetic powder is samarium iron nitrogen magnetic powder and / or neodymium iron nitrogen magnetic powder;

[0015] Further, the D50 of the samarium iron nitrogen magnetic powder is 1.9-3 μm, the D50 of the neodymium iron nitrogen magnetic powder is 1.5-1.9 μm, and the D50 of the ferrite magnetic powder is 1.5-1.8 μm; and / or

[0016] Further, the samarium iron nitrogen magnetic powder, the neodymium iron nitrogen magnetic powder and / or the ferrite magnetic powder are anisotropic;

[0017] Furthermore, in the magnetic material, the mass ratio of rare earth iron nitrogen magnetic powder to ferrite magnetic powder is (0.5-1):(0-0.5), and further, the mass ratio of rare earth iron nitrogen magnetic powder to ferrite magnetic powder is (0.5-0.9):(0.1-0.5).

[0018] According to the method of the first aspect, in step (1), during the extrusion molding, the extruder head adopts permanent magnetic orientation or electromagnetic orientation;

[0019] Furthermore, the orientation field of the permanent magnetic orientation is 8000 to 13000 Oe; or

[0020] Furthermore, the orientation field of the electromagnetic orientation is ≥13000Oe.

[0021] According to the method of the first aspect, the elastic substrate in the flame retardant magnetic absorption layer material is:

[0022] Polyvinyl chloride (PVC), further, the hardness of the polyvinyl chloride (PVC) is 40-100A;

[0023] Silicone rubber, further, the hardness of the silicone rubber is 40-70A; or

[0024] Thermoplastic elastomer, further, the melting point of the thermoplastic elastomer is 80-200°C, the thermoplastic elastomer, further, the thermoplastic elastomer is one or more of styrene-based thermoplastic elastomer, olefin-based thermoplastic elastomer, diene-based thermoplastic elastomer, vinyl chloride-based thermoplastic elastomer, urethane-based thermoplastic elastomer TPU, polyester-based thermoplastic elastomer TPEE, polyamide-based thermoplastic elastomer TPAE, thermoplastic elastomer thermoplastic resin EEA, thermoplastic vulcanized rubber TPV, and silicone-based thermoplastic elastomer, and further, the thermoplastic elastomer is one or more halogen-free materials among TPEE, TPU, TPV, and TPAE.

[0025] According to the method of the first aspect, the flame retardant in the flame retardant magnetic absorption layer material is selected from organic flame retardants and / or inorganic flame retardants, preferably halogen-free flame retardants;

[0026] Furthermore, the flame retardant magnetic absorption layer material also includes a processing aid, and the processing aid includes one or more of a coupling agent, a plasticizer, a toughening agent, a lubricant, and an antioxidant.

[0027] According to the method of the first aspect, wherein, in step (1), the magnetic material is surface-modified by a coupling agent;

[0028] Furthermore, the coupling agent is a silane coupling agent or a titanate coupling agent;

[0029] Furthermore, the magnetic material is modified at 80-150° C. using a coupling agent accounting for 0.2-2 wt % of the total weight of the magnetic material.

[0030] According to the method of the first aspect, wherein, in step (1), the outer layer material is selected from one or more of woven material, TPU, TPEE, TPV, and silicone rubber;

[0031] Further, the braided material is a flame retardant braided material;

[0032] Furthermore, the braided material is one or more of flame-retardant nylon, flame-retardant nylon, and flame-retardant aramid.

[0033] According to the method of the first aspect, in step (1), extrusion molding is performed by a single-screw wire extruder and a permanent magnetic orientation extruder head;

[0034] Further, the extrusion speed is ≥30 m / s;

[0035] Furthermore, when the elastic substrate is silicone rubber, the extruder and the die head are at room temperature;

[0036] Furthermore, the elastic substrate is a thermoplastic elastomer, and the temperature of each section of the screw of the extruder is 100-200°C; and / or

[0037] Furthermore, when the elastic substrate is a thermoplastic elastomer, the extruder die temperature is 120-200°C.

[0038] According to the method of the first aspect, in step (2), when the elastic substrate is a thermoplastic elastomer, it is shaped by baking at 200 to 300°C;

[0039] In step (2), when the elastic substrate is silicone rubber, vulcanization and shaping is performed through a heating channel at a temperature of 200 to 400° C.; and / or

[0040] In step (3), the wire is magnetized in a curled state using a spiral coil magnetizing device with a magnetic field of more than 35000 kOe or in a flat state using a groove magnetizing device.

[0041] The second aspect of the present invention provides a flame-retardant magnetic wire, which is prepared by the method of the first aspect;

[0042] Furthermore, the Shore hardness of the wire is ≤90A;

[0043] Furthermore, the flame retardant grade of the wire meets VW-1;

[0044] Further, the wire is halogen-free; and / or

[0045] Furthermore, the surface magnetic field strength of the wire in the magnetization direction is above 500 Gs.

[0046] According to the flame-retardant magnetic wire material of the second aspect, the thickness of the inner layer of the wire material is 0.3 to 2 mm, preferably 0.3 to 1 mm, and / or the thickness of the outer layer of the wire material is ≤1 mm, preferably ≤0.3 mm;

[0047] Furthermore, the wire core of the wire material comprises a single or multiple wires individually coated with an insulating layer;

[0048] Furthermore, a fiber material is also arranged inside the core of the wire, and the fiber material is selected from one or more of glass fiber, basalt fiber and aramid fiber;

[0049] Furthermore, a shielding layer is provided between the wire core and the middle sheath layer of the wire, and the shielding layer wraps the conductive wire and the fiber material.

[0050] The method for preparing the flame-retardant magnetic wire of the present invention has but is not limited to the following beneficial effects:

[0051] The preparation method of the present invention uses anisotropic rare earth iron nitrogen magnetic powder, further compounding rare earth iron nitrogen magnetic powder with ferrite magnetic powder, and using a die head with a magnetic field orientation function to extrude wire, without setting a heat-resistant shielding layer, and can achieve the current wire preparation scheme with the least flame retardant addition, the highest magnetic attraction performance, and the best mechanical properties. The prepared wire has good flexibility, good tear resistance and tensile properties, can maintain excellent flame retardant properties while reducing the amount of flame retardant added, and achieves high magnetic properties of the wire. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 A cross-sectional schematic diagram of the flame-retardant magnetic wire (without shielding layer) of the present invention is shown.

[0053] Figure 2 A cross-sectional schematic diagram of the flame-retardant magnetic wire (with a shielding layer) of the present invention is shown.

[0054] Figure 3A schematic diagram of the magnetic field orientation device (permanent magnetic orientation) of the extrusion head of the extrusion mechanism of the present invention is shown.

[0055] Figure 4 A schematic cross-sectional view of the magnetic field orientation device (permanent magnetic orientation) of the extrusion head of the extrusion mechanism of the present invention is shown.

[0056] Figure 5 A schematic diagram of the extruder head magnetic field orientation device (electromagnetic orientation) of the present invention is shown.

[0057] Figure 6 A schematic diagram of a magnetization scheme for the flame-retardant magnetic wire of the present invention is shown.

[0058] Figure 7 A schematic diagram showing the flame-retardant magnetic wire storage effect of the present invention is shown.

[0059] Description of reference numerals:

[0060] 1. Wire core; 11. Conducting wire; 2. Middle sheath; 3. Outer sheath; 4. Shielding layer; 5. Magnetic field orientation device; 51. Magnetic conductor; 52. Permanent magnet; 53. Wire outlet port; 54. Extrusion channel; 55. Magnetic field core mold; 6. Electromagnet; 61. Magnetic pole head; 62. Soft iron pole; 63. Yoke iron; 64. Coil; 7. Solenoid cylinder; 8. Wire to be magnetized; 9. Magnetizer; 10. Clamp. DETAILED DESCRIPTION

[0061] The present application is further described in detail below through the accompanying drawings and embodiments. Through these descriptions, the characteristics and advantages of the present application will become clearer and more specific.

[0062] The word "exemplary" is used exclusively herein to mean "serving as an example, embodiment, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. Although various aspects of the embodiments are shown in the drawings, the drawings are not necessarily drawn to scale unless otherwise noted.

[0063] In addition, the technical features involved in different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0064] The present invention provides a method for preparing a flame-retardant magnetic wire, wherein the flame-retardant magnetic wire is provided with a wire core, a middle cladding layer and an optional outer cladding layer from the inside to the outside, wherein the middle cladding layer is a flame-retardant magnetic attraction layer, and the method for preparing the wire comprises:

[0065] (1) Extruding a wire core and a flame-retardant magnetic absorption layer material together to obtain a wire core coated with a flame-retardant magnetic absorption layer, wherein the flame-retardant magnetic absorption layer material comprises an elastic substrate, a magnetic material and a flame retardant; wherein the magnetic material comprises rare earth iron nitrogen magnetic powder, and further, the magnetic material comprises rare earth iron nitrogen magnetic powder and ferrite magnetic powder;

[0066] Optionally, an outer coating layer is prepared on the outer side of the obtained wire core coated with the flame-retardant magnetic absorption layer;

[0067] (2) shaping the wire obtained in step (1);

[0068] (3) magnetizing the wire obtained in step (2) to obtain the flame-retardant magnetic wire;

[0069] Furthermore, in the flame-retardant magnetic absorption layer material, the content of the elastic substrate is 15wt% to 25wt%, the content of the magnetic material is 55wt% to 75wt%, and the content of the flame retardant is 5wt% to 15wt%.

[0070] In a preferred embodiment, the content of the elastic substrate is 15wt% to 20wt%, the content of the magnetic material is 65wt% to 75wt%, and the content of the flame retardant is 5wt% to 10wt%.

[0071] Rare earth iron nitrogen (R-Fe-N) material is a type of permanent magnetic material containing rare earth elements. a Fe b N c The chemical formula of wherein R is a rare earth element selected from one or more of samarium Sm, neodymium Nd, lanthanum La, cerium Ce, praseodymium Pr, promethium Pm, gadolinium Gd, terbium Tb, dysprosium Dy, europium Eu, holmium Ho, erbium Er, thulium Tm, ytterbium Yb, lutetium Lu, yttrium Y, and scandium Sc, and a, b, and c are non-zero natural numbers. The rare earth iron nitrogen magnetic powder of the present invention may be samarium iron nitrogen magnetic powder, neodymium iron nitrogen magnetic powder, and the like. Among them, samarium iron nitrogen may be one having Th2Zn 17 Sm2Fe 17 N x , NdFeN can be ThMn 12 NdFe 12 N x Compared with rare earth permanent magnet materials such as samarium cobalt and neodymium iron boron, rare earth iron nitrogen has better magnetic properties and good particle size characteristics, and has excellent anti-oxidation and anti-corrosion properties.

[0072] In order to achieve a good flame retardant effect, a common method in the prior art is to increase the use of flame retardants in composite materials. However, in the field of magnetic wires, excessive addition of flame retardants is not only not conducive to maintaining the flexibility and toughness of the material, but also greatly reduces the magnetic performance. In the technical solution of the present invention, by further adding ferrite magnetic powder, not only can the loss of magnetic properties be reduced, but also because of the characteristics of the oxide of the ferrite magnetic powder itself, it is beneficial to achieve flame retardant properties with less addition of flame retardants. In one embodiment, the rare earth iron nitrogen magnetic powder is samarium iron nitrogen magnetic powder and / or neodymium iron nitrogen magnetic powder;

[0073] Further, the D50 of the samarium iron nitrogen magnetic powder is 1.9-3 μm, the D50 of the neodymium iron nitrogen magnetic powder is 1.5-1.9 μm, and the D50 of the ferrite magnetic powder is 1.5-1.8 μm; and / or

[0074] Further, the samarium iron nitrogen magnetic powder, the neodymium iron nitrogen magnetic powder and / or the ferrite magnetic powder are anisotropic;

[0075] Furthermore, in the magnetic material, the mass ratio of rare earth iron nitrogen magnetic powder to ferrite magnetic powder is (0.5-1):(0-0.5), and further, the mass ratio of rare earth iron nitrogen magnetic powder to ferrite magnetic powder is (0.5-0.9):(0.1-0.5).

[0076] The magnetic material of the present invention can select isotropic or anisotropic magnetic powder. Further, the magnetic material powder is anisotropic samarium iron nitrogen powder with a D50 of 1.9 to 3 μm and / or anisotropic neodymium iron nitrogen powder with a D50 of 1.5 to 1.9 μm, and is further compounded with anisotropic ferrite magnetic powder to achieve flame retardant and magnetic performance improvement effects. Anisotropic rare earth iron nitrogen powder can achieve high magnetic properties that other magnetic powder materials on the market do not have under orientation conditions, and at the same time, based on the characteristics of nitrides, it has good corrosion resistance, rust resistance, aging resistance, and oxidation resistance. In addition, based on the particle size characteristics of samarium iron nitrogen magnetic powder D50 between 1.9 and 3 μm, neodymium iron nitrogen magnetic powder D50 between 1.5 and 1.9 μm, and ferrite magnetic powder D50 between 1.5-1.8 μm, it can be well combined with common elastomeric materials, so that the prepared wire has good flexibility while also having good tear resistance and tensile properties. When the D50 of the anisotropic rare earth iron nitrogen magnetic powder is too large (>3 μm), the magnetic properties of the anisotropic rare earth iron nitrogen magnetic powder are low, the magnetic attraction of the produced wire is not high, and the mechanical properties are poor.

[0077] In one embodiment, the mass ratio of rare earth iron nitrogen magnetic powder to ferrite magnetic powder in the magnetic material is (0.5-1): (0-0.5). By adjusting the appropriate ratio of magnetic powder to flame retardant in the flame-retardant magnetic absorption layer, the obtained wire has excellent magnetic absorption performance, flame retardant performance and mechanical properties. In a specific embodiment, the mass ratio of rare earth iron nitrogen to ferrite magnetic powder in the magnetic powder is (0.5-0.9): (0.1-0.5). When the content of ferrite magnetic powder is too much, the magnetic properties of the produced middle coating layer are too low to meet the requirements of the wire for magnetic attraction.

[0078] In one embodiment, in step (1), during the extrusion molding, the extruder head adopts permanent magnetic orientation or electromagnetic orientation;

[0079] Furthermore, the orientation field of the permanent magnetic orientation is 8000 to 13000 Oe; or

[0080] Furthermore, the orientation field of the electromagnetic orientation is ≥13000Oe.

[0081] In one embodiment, the elastic substrate in the flame retardant magnetic absorption layer material is:

[0082] Polyvinyl chloride (PVC), further, the hardness of the polyvinyl chloride (PVC) is 40-100A;

[0083] Silicone rubber, further, the hardness of the silicone rubber is 40-70A; or

[0084] Thermoplastic elastomer, further, the melting point of the thermoplastic elastomer is 80-200° C., the thermoplastic elastomer, further, the thermoplastic elastomer is one or more of styrene thermoplastic elastomer (SBS, SIS, SEBS, SEPS), olefin thermoplastic elastomer (TPO, TPV), diene thermoplastic elastomer (TPB, TPI), vinyl chloride thermoplastic elastomer (TPVC, TCPE), urethane thermoplastic elastomer (TPU), polyester thermoplastic elastomer (TPEE), polyamide thermoplastic elastomer (TPAE), thermoplastic elastomer thermoplastic resin (EEA, Ethylene Ethyl Acrylate ethylene-ethyl acrylate copolymer), thermoplastic vulcanizate (Thermoplastic Vulcanizate, TPV), silicone thermoplastic elastomer, and further, the thermoplastic elastomer is one or more halogen-free materials among TPEE, TPU, TPV, TPAE;

[0085] In one embodiment, the flame retardant in the flame retardant magnetic absorption layer material is selected from organic flame retardants and / or inorganic flame retardants, preferably halogen-free flame retardants;

[0086] Furthermore, the flame-retardant magnetic absorption layer material also includes a processing aid, and the processing aid includes one or more of a coupling agent, a plasticizer, a toughening agent, a lubricant, and an antioxidant.

[0087] The elastic substrate can be selected as one or more of PVC, silicone rubber, and thermoplastic elastomer, wherein the hardness of the PVC is 40-100A, for example, 40A, 50A, 60A, 70A, 80A, 90A, and 100A; the hardness of the silicone rubber is 40-70A, for example, 40A, 50A, 60A, and 70A; the thermoplastic elastomer is preferably a thermoplastic elastomer material with a melting point between 80 and 200 degrees Celsius, for example, the melting point can be 80°C, 100°C, 120°C, 150°C, 180°C, and 200°C. The use of these elastomers can achieve the following effects: the material has good flexibility and good molding fluidity, does not contain halogen, and meets safety and environmental protection standards. If the melting point of the selected thermoplastic elastomer is too low, the mechanical properties of the obtained wire are poor, and if the melting point of the selected thermoplastic elastomer is too high, the high temperature during the processing will lead to the loss of magnetic properties, and the obtained wire cannot achieve high magnetic properties.

[0088] The flame retardant of the present invention may be an organic flame retardant or an inorganic flame retardant. Organic flame retardants include, but are not limited to, flame retardants with bromine, chlorine, phosphorus-nitrogen, nitrogen, red phosphorus and compounds as main components, and inorganic flame retardants include, but are not limited to, flame retardants with antimony trioxide, magnesium hydroxide, aluminum hydroxide, etc. as main components. The flame retardant may contain halogen or not contain halogen, preferably a flame retardant without halogen.

[0089] The coupling agent, plasticizer, toughening agent and lubricant in the processing aids can be made of conventional materials and can be selected according to needs.

[0090] In one embodiment, in step (1), the magnetic material is surface-modified by a coupling agent;

[0091] Furthermore, the coupling agent is a silane coupling agent or a titanate coupling agent;

[0092] Furthermore, the magnetic material is modified at 80-150° C. using a coupling agent accounting for 0.2-2 wt % of the total weight of the magnetic material.

[0093] In a specific embodiment, the magnetic material is surface modified by using 0.5-2 wt % of a coupling agent, mixing and stirring at a temperature between 80° C. and 150° C., and drying.

[0094] The present invention utilizes a coupling agent to perform surface modification on a magnetic material, thereby increasing the fluidity of magnetic material powder and improving the bonding effect between the magnetic material powder and an elastomer material, thereby ensuring the orientation effect of the magnetic material in a magnetic field and the flexibility of the material.

[0095] In a specific embodiment, the flame retardant magnetic layer material is prepared into granular material and then the intermediate coating layer is prepared.

[0096] In one embodiment, in step (1), the outer layer material is selected from one or more of woven material, TPU, TPEE, TPV, and silicone rubber. Further, the woven material is a flame retardant woven material. Furthermore, the woven material is one or more of flame retardant nylon, flame retardant nylon, and flame retardant aramid.

[0097] In one embodiment, in step (1), extrusion molding is performed by a single screw wire extruder and a permanent magnetic orientation extruder head;

[0098] Further, the extrusion speed is ≥30 m / s;

[0099] Furthermore, when the elastic substrate is silicone rubber, the extruder and the die head are at room temperature;

[0100] Furthermore, when the elastic substrate is a thermoplastic elastomer, the temperature of each section of the screw of the extruder is 100 to 200° C.; and / or

[0101] Furthermore, when the elastic substrate is a thermoplastic elastomer, the extruder die temperature is 120-200°C.

[0102] When the temperature of the extruder die head is too high, high temperature demagnetization may occur.

[0103] In one embodiment, in step (2), when the elastic substrate is a thermoplastic elastomer, it is shaped by baking at 200 to 300° C.;

[0104] In step (2), when the elastic substrate is silicone rubber, vulcanization and shaping is performed through a heating channel at a temperature of 200 to 400° C.; and / or

[0105] In step (3), the wire is magnetized in a curled state using a spiral coil magnetizing device with a magnetic field of more than 35000 kOe or in a flat state using a groove magnetizing device.

[0106] The present invention also provides a flame-retardant magnetic wire, which is prepared by the above method;

[0107] Furthermore, the Shore A hardness of the wire is ≤90A, that is, the Shore A hardness of the wire of the present invention does not exceed 90 degrees;

[0108] Furthermore, the flame retardant grade of the wire reaches VW-1;

[0109] Further, the wire is halogen-free; and / or

[0110] Furthermore, the surface magnetic field strength of the wire in the magnetization direction is above 500 Gs.

[0111] In one embodiment, the thickness of the inner layer of the wire is 0.3-1 mm, and / or the thickness of the outer layer of the wire is ≤0.3 mm;

[0112] Furthermore, the wire core of the wire material comprises a single or multiple wires individually coated with an insulating layer;

[0113] Furthermore, a fiber material is also arranged inside the core of the wire, and the fiber material is selected from one or more of glass fiber, basalt fiber and aramid fiber;

[0114] Furthermore, a shielding layer is provided between the wire core and the middle sheath layer of the wire, and the shielding layer wraps the conductive wire and the fiber material.

[0115] The flame-retardant magnetic wire prepared by the invention consists of a wire core, a middle sheath layer and an outer sheath layer from inside to outside.

[0116] The core is composed of a single or multiple conductors with separate insulation layers, which can be twisted or arranged in parallel. Fiber materials such as glass fiber, basalt fiber, and aramid can be added to the core to enhance the tensile and heat dissipation performance. The core and fiber can be wrapped with materials such as aluminum foil as a shielding layer.

[0117] The middle layer is a flame retardant magnetic absorption layer, which is made of elastic substrate, magnetic material powder, flame retardant, and at least one of coupling agent, plasticizer, toughening agent, lubricant, and antioxidant, preferably halogen-free material. The thickness of the middle layer is preferably 0.3-1 mm.

[0118] The outer layer can be wrapped with woven materials (preferably flame-retardant woven materials, including but not limited to flame-retardant nylon, flame-retardant nylon, flame-retardant aramid, etc.), TPU, TPEE, TPV, silicone rubber and other materials. If woven materials are selected, glue can also be directly applied on the weaving. The thickness of the outer layer is preferably not more than 0.3 mm, and the outer layer material is preferably halogen-free.

[0119] Figure 1 A cross-sectional schematic diagram of the wire of the present invention is shown, which includes a wire core 1, a middle sheath 2 and an outer sheath 3 from the inside to the outside. The wire core 1 contains a plurality of wires 11. The wire core may include fiber materials to improve the mechanical properties and heat dissipation performance of the wire. Figure 2 As shown, a shielding layer 4 may be wrapped around the outside of the wire core.

[0120] After preparation, the outer diameter of the wire is preferably not more than 5 mm in thickness / width / diameter, the Shore hardness is ≤90A, and the flame retardant grade of the wire reaches VW-1.

[0121] In a specific embodiment, the preparation method comprises:

[0122] Mix in the following proportions:

[0123] 55wt%-75wt% magnetic powder,

[0124] 15wt%-25wt% of elastomeric material,

[0125] 10wt%-30wt% of processing aids, including 5wt%-15wt% of flame retardants.

[0126] The magnetic particles are prepared by using a twin-screw extruder, and the temperature of each screw section is 100-200°C.

[0127] Use a single screw wire extruder and an extruder head with magnetic field orientation to extrude flame retardant magnetic wire. The wire cross-section is round, oblate or rectangular, and the extrusion speed is ≥30 m / s. The screw temperature of each section of the extruder is 100-200℃, and the die temperature is 120-200℃. The extruder head adopts permanent magnetic orientation or electromagnetic orientation. In the case of permanent magnetic orientation, the orientation field can reach 8000-13000Oe; in the case of electromagnetic orientation, the orientation field is ≥13000Oe.

[0128] Figure 3 A schematic diagram of the magnetic field orientation device (permanent magnetic orientation) of the extrusion head of the extrusion mechanism of the present invention is shown, Figure 4 The cross-sectional schematic diagram of the magnetic field orientation device (permanent magnet orientation) is shown. The magnetic field orientation device 5 is provided with two magnetic conductors 51 and two permanent magnets 52, the permanent magnet 52 is sandwiched between the two magnetic conductors 51, and the two permanent magnets 52 are respectively located on opposite sides of the extrusion channel 54, and the magnetic field lines generated between the two permanent magnets penetrate the extrusion channel 54 to perform magnetic field orientation on the molten flame-retardant magnetic attraction in the extrusion channel 54, and the magnetic field core mold 55 can guide the passage of the wire, so that the wire can pass more smoothly. Figure 5The schematic diagram of the extruder head magnetic field orientation device (electromagnetic orientation) of the present invention is shown, including an electromagnet 6 and a magnetic field core mold (not shown in the figure), the N pole and S pole of the electromagnet 6 are relatively arranged, and there is a gap between the N pole and S pole of the electromagnet 6. Specifically, the electromagnet 6 is in a ring shape with a gap, so that the N pole and S pole of the electromagnet 6 are relatively arranged. The N pole and S pole of the electromagnet 6 are respectively connected to the magnetic pole head 61, and the magnetic pole head 61 is trapezoidal to strengthen the magnetic concentration effect. The upper ends of the two magnetic pole heads 61 are soft iron poles 62 and magnetic conductive materials (i.e., yoke iron 63) in turn. The magnetic conductive materials are connected to form a magnetic field loop, and coils 64 are arranged on both sides of each magnetic pole, and the magnetic lines of force of the coils 64 on both sides of the same magnetic pole are in the same direction. In the case of externally wrapped materials such as TPU, TPEE, TPV, etc., after the aforementioned middle layer is extruded, the outer layer is extruded and wrapped by a double-layer extrusion device. In the case of externally wrapped braided materials, the braided layer outer quilt is prepared by a braiding device.

[0129] If necessary, the wire curling shape can be initially shaped by baking equipment.

[0130] When silicone gel or silicone rubber is used as the elastic substrate of the middle cladding layer, after the surface of the magnetic powder is modified, the magnetic powder, processing aid and flame retardant are mixed in the aforementioned proportions, and the vulcanizer is added according to the conventional process. The mixing is uniform, and the wire is directly extruded at room temperature using a single-screw extruder with a magnetic field orientation function, and vulcanized and shaped through a heating channel at a temperature of 200 to 400°C.

[0131] The wire is magnetized using a spiral coil magnetizing device with a magnetic field of more than 35000kOe in a curled state and a groove magnetizing device in a flat state. After preparation, the surface magnetic field strength of the wire in the magnetization direction is more than 500Gs.

[0132] Figure 6 A schematic diagram of a magnetization scheme for the flame-retardant magnetic wire of the present invention is shown. The wire 8 to be magnetized is coiled on the solenoid cylinder 7, fixed by a clamp 10 and magnetized by a magnetizer 9. The magnetic field strength on the surface of the magnetized wire in the magnetization direction is above 500Gs, so that it can be stored conveniently. Figure 7 A schematic diagram showing the flame-retardant magnetic wire storage effect of the present invention is shown.

[0133] The present invention has no special restrictions on the sources of all raw materials. Unless otherwise specified, they are all conventional products that can be obtained commercially.

[0134] SmFeN magnetic powder was purchased from Ningxia Junci New Material Technology Co., Ltd.

[0135] Ferrite powder was purchased from Zhejiang Dongci Toda Magnetics Co., Ltd.

[0136] TPV, model 1190A-S0204, was purchased from GLS, USA.

[0137] TPEE, model SHF 50A-3S1981, was purchased from GLS, USA.

[0138] TPU, model Elastollan SP1150A15P, was purchased from BASF.

[0139] Silicone rubber, model 107 room temperature vulcanized silicone rubber, was purchased from Jinan Yingyu Chemical Co., Ltd.

[0140] PVC, model S080 PR-640, was purchased from Ningbo Formosa Plastics.

[0141] The wire core in the following embodiments uses a halogen-free flame-retardant five-core wire core, which is covered with an insulation layer.

[0142] The ferrite powder used in the following examples is anisotropic.

[0143] Example 1

[0144] Anisotropic SmFeN magnetic powder (D50 is 2.05 μm) and ferrite magnetic powder (D50 is 1.64 μm) are modified respectively using KH550 silane coupling agent equivalent to 1.5 wt% of the magnetic powder weight, including: dissolving KH550 silane coupling agent in anhydrous ethanol (silane coupling agent concentration is 20 wt%), adding magnetic powder, mixing and stirring at 110° C. using a Hensel mixing dryer and drying to obtain modified anisotropic SmFeN magnetic powder and modified ferrite magnetic powder.

[0145] 45wt% of modified anisotropic samarium iron nitrogen magnetic powder, 20wt% of modified ferrite magnetic powder, 20wt% of TPV (melting point 170°C), 10wt% of phosphorus nitrogen halogen-free flame retardant KSW-03, and 5wt% of additives containing antioxidants and plasticizers (including 2wt% of antioxidant 1076 and 3wt% of plasticizer DEHP) are fully mixed, and magnetic particles are prepared using a twin-screw extruder, and the temperature of each screw section is 100-200°C.

[0146] A single screw wire extruder is used to extrude the halogen-free flame-retardant magnetic wire through a permanent magnetic orientation extruder head with an orientation field of 12000Oe. The wire diameter cross-section shape is oblate, and the extrusion speed is 30 m / s. The screw temperature of each section of the extruder is 100-200℃, and the die temperature is 150℃. The thickness of the middle layer is 0.6mm.

[0147] The flame retardant nylon woven outer sheath is prepared by using a weaving device, and the thickness of the outer sheath layer is 0.3 mm.

[0148] The wire coil shape is initially shaped by baking equipment at a baking temperature of 280°C.

[0149] The wire is magnetized in a coiled state using a spiral coil magnetizing device with a magnetic field of 35000 kOe.

[0150] The core diameter of the magnetic data cable is 2.8mm, the finished height of the wire section is 4.6mm, the width of the flat part is 0.5mm, the width of the wire section is 4.8mm, and the Shore hardness is 70A. After magnetization, the flat part measured magnetic field is 650Gs, and the finished wire is flame-retardant tested using cable flame-retardant testing equipment according to the UL1581 standard, and the flame-retardant grade is VW-1.

[0151] Example 2

[0152] Anisotropic SmFeN magnetic powder (D50 is 2.1 μm) and ferrite magnetic powder (D50 is 1.75 μm) are modified respectively using KH550 silane coupling agent equivalent to 2 wt% of the magnetic powder weight, including: dissolving KH550 silane coupling agent in anhydrous ethanol (silane coupling agent concentration is 20 wt%), adding magnetic powder, mixing and stirring at 130° C. using a Hensel mixing dryer and drying to obtain modified anisotropic SmFeN magnetic powder and modified ferrite magnetic powder.

[0153] 48wt% of modified anisotropic samarium iron nitrogen magnetic powder, 22wt% of modified ferrite magnetic powder, 20wt% of TPEE (melting point 150°C), 5wt% of aluminum hydroxide halogen-free flame retardant, and 5wt% of additives containing antioxidants and toughening agents (including 2wt% of antioxidant 1076 and 3wt% of toughening agent DEHP) are fully mixed, and magnetic particles are prepared using a twin-screw extruder, and the temperature of each screw section is 100-200°C.

[0154] A single screw wire extruder is used to extrude the halogen-free flame-retardant magnetic wire through an electromagnetic orientation extruder head with an orientation field of 14000Oe. The wire diameter cross-section shape is round and the extrusion speed is 30 m / s. The screw temperature of each section of the extruder is 100-200°C, and the die temperature is 180°C. The thickness of the middle layer is 0.5mm.

[0155] The outer layer is wrapped with halogen-free flame-retardant TPEE extruded through a double-layer extrusion device, and the thickness of the outer layer is 0.3mm.

[0156] The wire coil shape is initially shaped by baking equipment at a baking temperature of 280°C.

[0157] The wire is magnetized in a coiled state using a spiral coil magnetizing device with a magnetic field of 35000 kOe.

[0158] The core diameter of the magnetic data cable is 2.8mm, the cross-section diameter is 4.4mm, and the Shore hardness is 80A. After magnetization, the flat part is measured to have a surface magnetism of 750Gs. The cable flame retardant test equipment is used to conduct a flame retardant test on the completed cable according to the UL1581 standard, and the flame retardant grade is VW-1.

[0159] Example 3

[0160] Anisotropic SmFeN magnetic powder (D50 is 2.3 μm) and ferrite magnetic powder (D50 is 1.68 μm) are modified respectively using KH550 silane coupling agent equivalent to 0.5 wt% of the magnetic powder weight, including: dissolving KH550 silane coupling agent in anhydrous ethanol (silane coupling agent concentration is 20 wt%), adding magnetic powder, mixing and stirring at 80° C. and drying using a Hensel mixing dryer to obtain modified anisotropic SmFeN magnetic powder and modified ferrite magnetic powder.

[0161] 48wt% of modified anisotropic samarium iron nitrogen magnetic powder, 25wt% of modified ferrite magnetic powder, 15wt% of TPU (melting point 200°C), 7wt% of magnesium hydroxide halogen-free flame retardant, and 5wt% of additives containing antioxidants, toughening agents, and lubricants (including 2wt% of antioxidant 1076, 2wt% of toughening agent DEHP, and 1wt% of lubricant PMX-200) are fully mixed, and magnetic particles are prepared using a twin-screw extruder, and the temperature of each screw section is 100-200°C.

[0162] A single screw wire extruder is used to extrude the halogen-free flame-retardant magnetic wire through an electromagnetic orientation extruder head with an orientation field of 14000Oe. The wire diameter cross-section shape is square and the extrusion speed is 30 m / s. The screw temperature of each section of the extruder is 100-200°C, and the die temperature is 180°C. The thickness of the middle layer is 0.8mm.

[0163] The flame retardant aramid braided outer sheath is prepared by braiding equipment, and the thickness of the outer sheath layer is 0.3 mm.

[0164] The wire coil shape is initially shaped by baking equipment at a baking temperature of 280°C.

[0165] Using a groove magnetizing device with a magnetic field of 35000kOe and a pole width interval of 10mm, flat magnetization is performed along the height direction of the wire.

[0166] The core of the magnetic data cable is laid flat, with a width of 4mm and a height of 1.5mm. The finished width of the wire section is 5mm, the height is 3.7mm, and the Shore hardness is 90A. After magnetization, the height direction measured magnetic field is 850Gs. The finished wire is flame-retardant tested using cable flame-retardant testing equipment according to the UL1581 standard, and the flame-retardant grade is VW-1.

[0167] Example 4

[0168] Anisotropic SmFeN magnetic powder (D50 is 2.78 μm) and ferrite magnetic powder (D50 is 1.73 μm) are modified respectively using KH550 silane coupling agent equivalent to 1.3 wt% of the magnetic powder weight, including: dissolving KH550 silane coupling agent in anhydrous ethanol (silane coupling agent concentration is 20 wt%), adding magnetic powder, mixing and stirring at 110° C. and drying using a Hensel mixing dryer to obtain modified anisotropic SmFeN magnetic powder and modified ferrite magnetic powder.

[0169] 45wt% of modified anisotropic samarium iron nitrogen magnetic powder, 20% of modified ferrite magnetic powder, 20% of silicone rubber, 10% of phosphorus nitrogen flame retardant KSW-03, and additives containing antioxidants and plasticizers with a combined proportion of 4.5% (including 2wt% of antioxidant 1076 and 2.5wt% of plasticizer DEHP) are fully mixed, and 0.5wt% of vulcanizer TMTD is added, and mixed evenly at room temperature using an internal mixer, and a single-screw wire extruder is used to extrude the flame-retardant magnetic wire at room temperature through a permanent magnetic orientation extruder head with an orientation field of 12000Oe. The cross-sectional shape of the wire diameter is oblate, and the extrusion speed is 30 meters / second. The extruder screw and die head do not heat up. The thickness of the middle layer is 0.8mm. After the wire is extruded, it is vulcanized and shaped through a 300℃ heating channel.

[0170] The wire is magnetized in a coiled state using a spiral coil magnetizing device with a magnetic field of 35000 kOe.

[0171] The core diameter of the magnetic data cable is 2.8mm, the finished height of the wire section is 4.4mm, the width of the flat part is 0.5mm, the width of the wire section is 4.6mm, and the Shore hardness is 70A. After magnetization, the flat part measured magnetic field is 700Gs. The finished wire is flame-retardant tested using cable flame-retardant testing equipment in accordance with the UL1581 standard, and the flame-retardant grade is VW-1.

[0172] Example 5

[0173] Anisotropic SmFeN magnetic powder (D50 is 2.53 μm) and ferrite magnetic powder (D50 is 1.65 μm) are modified respectively using KH550 silane coupling agent equivalent to 1.5 wt% of the magnetic powder weight, including: dissolving KH550 silane coupling agent in anhydrous ethanol (silane coupling agent concentration is 20 wt%), adding magnetic powder, mixing and stirring at 130° C. using a Hensel mixing dryer and drying to obtain modified anisotropic SmFeN magnetic powder and modified ferrite magnetic powder.

[0174] 48wt% of modified anisotropic samarium iron nitrogen magnetic powder, 22wt% of modified ferrite magnetic powder, 15wt% of TPEE (melting point 150°C), 5wt% of PVC (melting point 200°C), 5wt% of aluminum hydroxide halogen-free flame retardant, and 5wt% of additives containing antioxidants and toughening agents (including 2wt% of antioxidant 1076 and 3wt% of toughening agent DEHP) are fully mixed, and magnetic particles are prepared using a twin-screw extruder, and the temperature of each screw section is 100-200°C.

[0175] A single screw wire extruder is used to extrude the halogen-free flame-retardant magnetic wire through an electromagnetic orientation extruder head with an orientation field of 14000Oe. The wire diameter cross-section shape is round and the extrusion speed is 30 m / s. The screw temperature of each section of the extruder is 100-200°C, and the die temperature is 180°C. The thickness of the middle layer is 0.6mm.

[0176] The outer layer is wrapped with halogen-free flame-retardant TPEE extruded through a double-layer extrusion device, and the thickness of the outer layer is 0.3mm.

[0177] The wire coil shape is initially shaped by baking equipment at a baking temperature of 280°C.

[0178] The wire is magnetized in a coiled state using a spiral coil magnetizing device with a magnetic field of 35000 kOe.

[0179] The core diameter of the magnetic data cable is 3.0mm, the finished diameter of the wire section is 4.6mm, and the Shore hardness is 90A. After magnetization, the flat part is measured to have a surface magnetism of 800Gs. The finished wire is tested for flame retardancy using cable flame retardant testing equipment in accordance with the UL1581 standard, and the flame retardancy grade is VW-1.

[0180] Example 6

[0181] Anisotropic SmFeN magnetic powder (D50 is 1.95 μm) is modified using a KH550 silane coupling agent equivalent to 2 wt% of the magnetic powder weight, comprising: dissolving the KH550 silane coupling agent in anhydrous ethanol (silane coupling agent concentration is 20 wt%), adding the magnetic powder, mixing and stirring at 110° C. using a Hensel mixing dryer and drying to obtain modified anisotropic SmFeN magnetic powder.

[0182] 55wt% of modified anisotropic samarium iron nitrogen magnetic powder, 20wt% of TPV (melting point 170°C), 20wt% of phosphorus nitrogen halogen-free flame retardant KSW-03, and 5wt% of additives containing antioxidants and plasticizers (including 2wt% of antioxidant 1076 and 3wt% of plasticizer DEHP) are fully mixed, and magnetic particles are prepared using a twin-screw extruder, and the temperature of each screw section is 100-200°C.

[0183] A single screw wire extruder is used to extrude the halogen-free flame-retardant magnetic wire through a permanent magnetic orientation extruder head with an orientation field of 12000Oe. The wire diameter cross-section shape is oblate, and the extrusion speed is 30 m / s. The screw temperature of each section of the extruder is 100-200℃, and the die temperature is 150℃. The thickness of the middle layer is 0.6mm.

[0184] The flame retardant nylon woven outer sheath is prepared by using a weaving device, and the thickness of the outer sheath layer is 0.3 mm.

[0185] The wire coil shape is initially shaped by baking equipment at a baking temperature of 280°C.

[0186] The wire is magnetized in a coiled state using a spiral coil magnetizing device with a magnetic field of 35000 kOe.

[0187] The core diameter of the magnetic data cable is 2.8mm, the finished height of the wire section is 4.6mm, the width of the flat part is 0.5mm, the width of the wire section is 4.8mm, and the Shore hardness is 65A. After magnetization, the flat part measured magnetic field is 700Gs, and the finished wire is flame-retardant tested using cable flame-retardant testing equipment according to the UL1581 standard, and the flame-retardant grade is VW-1.

[0188] Example 7

[0189] Anisotropic SmFeN magnetic powder (D50 is 2.15 μm) and ferrite magnetic powder (D50 is 1.70 μm) are modified respectively using KH550 silane coupling agent equivalent to 0.5 wt% of the magnetic powder weight, including: dissolving KH550 silane coupling agent in anhydrous ethanol (silane coupling agent concentration is 20 wt%), adding magnetic powder, mixing and stirring at 110° C. and drying using a Hensel mixing dryer to obtain modified anisotropic SmFeN magnetic powder and modified ferrite magnetic powder.

[0190] 35wt% of modified anisotropic samarium iron nitrogen magnetic powder, 35wt% of modified ferrite magnetic powder, 20wt% of TPV (melting point 170°C), 5wt% of phosphorus nitrogen halogen-free flame retardant KSW-03, and 5wt% of additives containing antioxidants and plasticizers (including 2wt% of antioxidant 1076 and 3wt% of plasticizer DEHP) are fully mixed, and magnetic particles are prepared using a twin-screw extruder, and the temperature of each screw section is 100-200°C.

[0191] A single screw wire extruder is used to extrude the halogen-free flame-retardant magnetic wire through a permanent magnetic orientation extruder head with an orientation field of 12000Oe. The wire diameter cross-section shape is oblate, and the extrusion speed is 30 m / s. The screw temperature of each section of the extruder is 100-200℃, and the die temperature is 150℃. The thickness of the middle layer is 0.6mm.

[0192] The flame retardant nylon woven outer sheath is prepared by using a weaving device, and the thickness of the outer sheath layer is 0.3 mm.

[0193] The wire coil shape is initially shaped by baking equipment at a baking temperature of 280°C.

[0194] The wire is magnetized in a coiled state using a spiral coil magnetizing device with a magnetic field of 35000 kOe.

[0195] The core diameter of the magnetic data cable is 2.8mm, the finished height of the wire section is 4.6mm, the width of the flat part is 0.5mm, the width of the wire section is 4.8mm, and the Shore hardness is 70A. After magnetization, the flat part measured magnetic field is 550Gs. The finished wire is flame-retardant tested using cable flame-retardant testing equipment according to the UL1581 standard, and the flame-retardant grade is VW-1.

[0196] Example 8

[0197] Anisotropic NdFeN magnetic powder (D50 is 1.65 μm) and ferrite magnetic powder (D50 is 1.70 μm) are modified respectively using KH550 silane coupling agent equivalent to 1.5 wt% of the magnetic powder weight, including: dissolving KH550 silane coupling agent in anhydrous ethanol (silane coupling agent concentration is 20 wt%), adding magnetic powder, mixing and stirring at 120° C. using a Hensel mixing dryer and drying to obtain modified anisotropic NdFeN magnetic powder and modified ferrite magnetic powder.

[0198] 55wt% of modified anisotropic NdFeN magnetic powder, 15wt% of modified ferrite magnetic powder, 20wt% of TPV (melting point 170°C), 5wt% of phosphorus-nitrogen halogen-free flame retardant KSW-03, and 5wt% of additives containing antioxidants and plasticizers (including 2wt% of antioxidant 1076 and 3wt% of plasticizer DEHP) are fully mixed, and magnetic particles are prepared using a twin-screw extruder, and the temperature of each screw section is 100-200°C.

[0199] A single screw wire extruder is used to extrude the halogen-free flame-retardant magnetic wire through a permanent magnetic orientation extruder head with an orientation field of 12000Oe. The wire diameter cross-section shape is oblate, and the extrusion speed is 30 m / s. The screw temperature of each section of the extruder is 100-200℃, and the die temperature is 150℃. The thickness of the middle layer is 0.8mm.

[0200] The flame retardant nylon woven outer sheath is prepared by using a weaving device, and the thickness of the outer sheath layer is 0.3 mm.

[0201] The wire coil shape is initially shaped by baking equipment at a baking temperature of 280°C.

[0202] The wire is magnetized in a coiled state using a spiral coil magnetizing device with a magnetic field of 35000 kOe.

[0203] The core diameter of the magnetic data cable is 2.8mm, the finished height of the wire section is 5.0mm, the width of the flat part is 0.7mm, the width of the wire section is 5.2mm, and the Shore hardness is 65A. After magnetization, the flat part measured magnetic field is 550Gs. The finished wire is flame-retardant tested using cable flame-retardant testing equipment according to the UL1581 standard, and the flame-retardant grade is VW-1.

[0204] Comparative Example 1

[0205] The material in Example 1 was extruded through a die without a magnetic field orientation function. The other production processes were exactly the same. After the magnetization was completed, the flat part had a measured surface magnetism of 280Gs and a Shore hardness of 70A. The finished wire was flame retardant tested using a cable flame retardant testing device using the UL1581 standard, and the flame retardant grade was VW-1.

[0206] Comparative Example 2

[0207] The magnetic powders (anisotropic SmFeN magnetic powder and ferrite magnetic powder) in Example 1 were all replaced with isotropic NdFeB magnetic powder (D50 is 103 μm), and extruded through a die head without magnetic field orientation function. The other production processes were completely the same. After magnetization, the flat part measured surface magnetic field was 480Gs, the Shore hardness was 90A, and the finished wire was flame retardant tested using cable flame retardant testing equipment according to UL1581 standard, and failed.

[0208] Comparative Example 3

[0209] The mixture ratio in Example 1 was changed to 45wt% of modified isotropic samarium iron nitrogen magnetic powder, 15% of modified ferrite magnetic powder, 20% of TPV, 15% of phosphorus nitrogen halogen-free flame retardant, and 5% of additives containing antioxidants and plasticizers, and fully mixed, and extruded through a die head without magnetic field orientation function. The other production processes were exactly the same. After magnetization, the flat part measured surface magnetism of 450Gs, Shore hardness of 90A, and the completed wire was flame retardant tested using cable flame retardant test equipment using UL1581 standard, and failed.

[0210] Comparative Example 4

[0211] The flame retardant in the mixture components in Example 1 is replaced with anisotropic samarium iron nitrogen magnetic powder, that is, 55wt% of modified anisotropic samarium iron nitrogen magnetic powder, 20% of modified ferrite magnetic powder, 20% of TPV, and 5% of additives containing antioxidants and plasticizers are fully mixed, and the other production processes are completely the same.

[0212] After magnetization, the flat part measured surface magnetism was 700Gs, and the Shore hardness was 85A. The completed wire was flame-retardant tested using cable flame-retardant testing equipment according to the UL1581 standard, and failed.

[0213] Comparative Example 5

[0214] In Example 1, the anisotropic samarium iron nitrogen magnetic powder and ferrite magnetic powder are not modified by KH550 silane coupling agent, and the other production processes are completely the same. After the magnetization is completed, the flat part has a measured surface magnetism of 400Gs and a Shore hardness of 90A. The completed wire is flame retardantly tested using a cable flame retardant testing equipment according to the UL1581 standard, and the flame retardant grade is VW-1.

[0215] Comparative Example 6

[0216] 86.5wt% of anisotropic SmFeN magnetic powder, 11wt% of TPU, and 2.5wt% of antioxidant and lubricant were fully mixed, and a twin-screw extruder was used to prepare a middle layer granular material, wherein the D50 of the anisotropic SmFeN magnetic powder was 4μm.

[0217] The powders including fillers and pigments accounting for 86.5wt%, TPU 11wt%, phosphorus nitrogen flame retardant KSW-03, antioxidant 1076 and lubricant PMX-200 silicone oil accounting for a total of 2.5wt% (mass ratio 1:1:1) are fully mixed, and the outer layer granular material is prepared using a twin-screw extruder.

[0218] A single-screw wire extruder is used to extrude the middle layer granules, and a double-layer extrusion device is used to extrude the outer layer granules.

[0219] The wire core diameter is 2.8mm, the thickness of the middle sheath is 0.7mm, and the thickness of the outer sheath is 0.4mm. The wire is magnetized in a curled state using a spiral coil magnetizing device. After magnetization, the surface magnetism of the wire is 200Gs, and the Shore hardness is 95A. The flame retardant test of the completed wire is carried out using a cable flame retardant test device using the UL1581 standard, and it fails.

[0220] The wires in Examples 1-8 and Comparative Examples 1-6 were subjected to high temperature winding and cold bending experiments respectively.

[0221] High temperature winding test conditions: 100℃ / 1 hour, the diameter of the winding mandrel is twice the outer diameter of the wire, observe whether the wire has cracking defects, no cracking defects are qualified, and cracking defects are unqualified;

[0222] Cold bending test experimental conditions: -20℃ / 4 hours, the diameter of the winding mandrel is twice the outer diameter of the wire, observe whether the wire has cracking defects, no cracking defects are qualified, and cracking defects are unqualified.

[0223] The test comparison is shown in Table 1 below:

[0224] Table 1

[0225] Serial number Surface magnetism Flame retardant test hardness High temperature winding Cold bending test Example 1 650Gs VW-1 70A qualified qualified Example 2 750Gs VW-1 80A qualified qualified Example 3 850Gs VW-1 90A qualified qualified Example 4 700Gs VW-1 70A qualified qualified Example 5 800Gs VW-1 90A qualified qualified Example 6 700Gs VW-1 65A qualified qualified Example 7 550Gs VW-1 70A qualified qualified Example 8 550Gs VW-1 65A qualified qualified Comparative Example 1 280Gs VW-1 70A qualified qualified Comparative Example 2 480Gs Failure 90A Failure Failure Comparative Example 3 450Gs Failure 90A Failure Failure Comparative Example 4 700Gs Failure 85A qualified qualified Comparative Example 5 400Gs VW-1 90A Failure Failure Comparative Example 6 200Gs Failure 95A Failure Failure

[0226] It can be seen from the above results that the wires prepared in Examples 1-8 of the present invention all have good flame retardant properties and high surface magnetism, and exhibit excellent mechanical properties in high temperature winding experiments and cold bending test experiments. The flame retardant magnetic absorption layer material of comparative example 1 is extruded through a die head without magnetic field orientation function, which results in low surface magnetism and cannot meet the magnetic adsorption requirements of the wire; comparative example 2 uses isotropic NdFeB magnetic powder as the magnetic material, and compared with the scheme of compounding anisotropic SmFeN magnetic powder and ferrite magnetic powder in embodiment 1, the flame retardant effect is poor and the mechanical properties are also poor; comparative example 3 uses isotropic SmFeN magnetic powder and increases the content of flame retardant. The surface magnetism of the prepared wire is low, and the flame retardant effect and mechanical properties cannot reach the level of the embodiment; comparative example 4 does not add flame retardant and fails the flame retardant test; the anisotropic SmFeN magnetic powder and ferrite magnetic powder of comparative example 5 are not modified by coupling agent, and the surface magnetism is only 400Gs. The magnetic properties fail to reach the level of the embodiment and the mechanical properties are unqualified; comparative example 6 adopts the prior art CN 113674921 B discloses a method, and uses samarium iron nitrogen magnetic powder with a D50 of 4 μm as the magnetic material, and only adds a flame retardant to the outer layer. Since the D50 of the anisotropic samarium iron nitrogen magnetic powder in comparative example 6 is too large, its magnetic properties are relatively low, the magnetic attraction of the wire is not high (surface magnetism 200 Gs), the bonding with the elastomer is also poor, and the hardness is too high (95A), resulting in the flame retardant properties and mechanical properties failing to reach the level of the embodiment.

[0227] The present application has been described above in conjunction with preferred embodiments, but these embodiments are only exemplary and serve only as an illustration. On this basis, various replacements and improvements may be made to the present application, all of which fall within the scope of protection of the present application.

Claims

1. A method for preparing a flame-retardant magnetic wire, characterized in that: The flame-retardant magnetic wire is provided with a wire core, a middle layer and an optional outer layer from the inside to the outside, wherein the middle layer is a flame-retardant magnetic layer, and the preparation method of the wire comprises: (1) Extruding a wire core and a flame-retardant magnetic absorption layer material together to obtain a wire core coated with a flame-retardant magnetic absorption layer, wherein the flame-retardant magnetic absorption layer material comprises an elastic substrate, a magnetic material and a flame retardant; wherein the magnetic material comprises rare earth iron nitrogen magnetic powder, preferably, the magnetic material comprises rare earth iron nitrogen magnetic powder and ferrite magnetic powder; Optionally, an outer coating layer is prepared on the outer side of the obtained wire core coated with the flame-retardant magnetic absorption layer; (2) shaping the wire obtained in step (1); (3) magnetizing the wire obtained in step (2) to obtain the flame-retardant magnetic wire; Preferably, in the flame-retardant magnetic absorption layer material, the content of the elastic substrate is 15wt% to 25wt%, the content of the magnetic material is 55wt% to 75wt%, and the content of the flame retardant is 5wt% to 15wt%.

2. The method according to claim 1, characterized in that The rare earth iron nitrogen magnetic powder is samarium iron nitrogen magnetic powder and / or neodymium iron nitrogen magnetic powder; Preferably, the D50 of the samarium iron nitrogen magnetic powder is 1.9-3 μm, the D50 of the neodymium iron nitrogen magnetic powder is 1.5-1.9 μm, and the D50 of the ferrite magnetic powder is 1.5-1.8 μm; and / or Preferably, the samarium iron nitrogen magnetic powder, the neodymium iron nitrogen magnetic powder and / or the ferrite magnetic powder are anisotropic; More preferably, in the magnetic material, the mass ratio of the rare earth iron nitrogen magnetic powder to the ferrite magnetic powder is (0.5-1):(0-0.5), and further preferably (0.5-0.9):(0.1-0.5).

3. The method according to claim 1 or 2, characterized in that: In step (1), during the extrusion molding, the extruder head adopts permanent magnetic orientation or electromagnetic orientation; Preferably, the orientation field of the permanent magnetic orientation is 8000 to 13000 Oe; or Preferably, the orientation field of the electromagnetic orientation is ≥13000 Oe.

4. The method according to any one of claims 1 to 3, characterized in that The elastic substrate in the flame retardant magnetic absorption layer material is: Polyvinyl chloride (PVC), preferably, the hardness of the polyvinyl chloride (PVC) is 40-100A; Silicone rubber, preferably, the hardness of the silicone rubber is 40-70A; and / or Thermoplastic elastomer, preferably, the melting point of the thermoplastic elastomer is 80-200°C, and the thermoplastic elastomer is more preferably one or more of styrene-based thermoplastic elastomer, olefin-based thermoplastic elastomer, diene-based thermoplastic elastomer, vinyl chloride-based thermoplastic elastomer, urethane-based thermoplastic elastomer TPU, polyester-based thermoplastic elastomer TPEE, polyamide thermoplastic elastomer TPAE, thermoplastic elastomer thermoplastic resin EEA, thermoplastic vulcanized rubber TPV, and silicone-based thermoplastic elastomer, and is further preferably one or more halogen-free materials among TPEE, TPU, TPV, and TPAE.

5. The method according to any one of claims 1 to 4, characterized in that The flame retardant in the flame retardant magnetic absorption layer material is selected from organic flame retardants and / or inorganic flame retardants, preferably halogen-free flame retardants; Preferably, the flame-retardant magnetic absorption layer material also includes a processing aid, and the processing aid includes one or more of a coupling agent, a plasticizer, a toughening agent, a lubricant, and an antioxidant.

6. The method according to any one of claims 1 to 5, characterized in that In step (1), the magnetic material is surface-modified by a coupling agent; Preferably, the coupling agent is a silane coupling agent or a titanate coupling agent; More preferably, the magnetic material is modified at 80-150° C. using a coupling agent in an amount of 0.2-2 wt % based on the total weight of the magnetic material.

7. The method according to any one of claims 1 to 6, characterized in that In step (1), the outer layer material is selected from one or more of woven material, TPU, TPEE, TPV, and silicone rubber. The woven material is preferably a flame retardant woven material, and more preferably one or more of flame retardant nylon, flame retardant nylon, and flame retardant aramid.

8. The method according to any one of claims 1 to 7, characterized in that In step (1), extrusion molding is performed by a single screw wire extruder and a permanent magnetic orientation extruder head; Preferably, the extrusion speed is ≥30 m / s; Preferably, when the elastic substrate is silicone rubber, the extruder and the die head are at room temperature; Preferably, the elastic substrate is a thermoplastic elastomer, and the screw temperature of each section of the extruder is 100-200°C; and / or Preferably, when the elastic substrate is a thermoplastic elastomer, the extruder die temperature is 120-200°C.

9. The method according to claims 1 to 8, characterized in that In step (2), when the elastic substrate is a thermoplastic elastomer, the elastic substrate is baked at 200 to 300° C. to set the elastic substrate; In step (2), when the elastic substrate is silicone rubber, vulcanization and shaping is performed through a heating channel at a temperature of 200 to 400° C.; and / or In step (3), the wire is magnetized in a curled state using a spiral coil magnetizing device with a magnetic field of more than 35000 kOe or in a flat state using a groove magnetizing device.

10. A flame-retardant magnetic wire, characterized in that: The wire is prepared by the method according to any one of claims 1 to 9; Preferably, the Shore hardness of the wire is ≤90A; Preferably, the flame retardant grade of the wire meets VW-1; Preferably, the wire is halogen-free; and / or Preferably, the surface magnetic field strength of the wire in the magnetization direction is above 500 Gs.

11. The flame-retardant magnetic wire according to claim 10, characterized in that: The thickness of the inner layer of the wire is 0.3 to 2 mm, preferably 0.3 to 1 mm, and / or the thickness of the outer layer of the wire is ≤ 1 mm, preferably ≤ 0.3 mm; Preferably, the wire core of the wire comprises a single or multiple wires individually coated with an insulation layer; More preferably, a fiber material is further provided inside the core of the wire, and the fiber material is selected from one or more of glass fiber, basalt fiber, and aramid; Further preferably, a shielding layer is provided between the wire core and the middle sheath layer of the wire, and the shielding layer wraps the conductive wire and the fiber material.

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