Composite enameled round copper wire and preparation method thereof

Abstract

The invention discloses a composite enameled round copper wire and a preparation method thereof, and belongs to the technical field of enameled wires. The composite enameled round copper wire comprises a steel core layer, a copper-clad layer, a main insulating layer and a surface layer, the steel core layer is uniformly covered with the copper-clad layer, the surface of the copper-clad layer is coated with the main insulating layer, and the main insulating layer is covered with the surface layer; the component of the steel core layer is steel, the component of the copper-clad layer is copper, and the component of the main insulating layer is a polyurethane paint surface layer prepared from basic components of modified polyester resin and blocked isocyanate resin and an organic solvent according to a preset proportion, namely, the surface layer is a polyamide resin paint surface layer. The invention further provides a process that steel is placed in a core part to serve as a base body, the surface of the steel is concentrically, evenly and continuously coated with a copper layer with a certain thickness, so that copper and steel are firmly combined together to form the copper-clad steel bimetal wire, and the copper-clad steel bimetal wire has the excellent electrical performance and corrosion resistance of copper and also has the high strength of steel. The technical problem of how to improve the product performance of the enameled round copper wire is solved.

Description

Technical Field

[0001] The invention relates to the technical field of enameled wires, and in particular to a composite enameled round copper wire and a preparation method thereof. Background Art

[0002] Enameled round copper wire is a special enameled wire, the conductor part of which is made of copper round wire. After annealing and softening, the wire is coated with one or more layers of insulating varnish on the surface, and then baked and cured to form an insulating layer. Therefore, the enameled round copper wire consists of two parts: the copper conductor and the insulating layer.

[0003] Enameled round copper wire has excellent electrical, thermal and mechanical properties and is suitable for winding various electromagnetic coils. Its self-adhesive characteristics make the manufacture of coils easier and more convenient. The coils can be bonded and formed by simply heating or solvent treating the wound coils. This forming method not only simplifies the coil manufacturing process and improves production efficiency, but also helps save energy and improve environmental pollution.

[0004] In addition, the enameled round copper wire also has excellent chemical corrosion resistance, wear resistance and high temperature resistance, which can meet the use requirements of electromagnetic coils in various complex environments.

[0005] Based on this, Chinese patent CN102820075A discloses a hollow conductor enameled copper round wire, which includes a copper round wire conductor and an insulating layer, wherein the insulating layer is evenly coated on the outer layer of the copper round wire conductor, and the copper round wire conductor is a hollow conductor. This hollow enameled copper round wire can reduce the temperature rise and loss during the energy conversion process of the motor or transformer winding, and obtain better efficiency and performance.

[0006] However, the enameled copper round wire disclosed above still has technical problems such as difficult manufacturing process and poor mechanical properties. Specifically, the enameled wire is the material for manufacturing motor windings. The motor converts electrical energy into mechanical energy through the enameled wire windings. The enameled wire consists of two parts: a conductor and an insulating layer. The conductor material is a highly conductive material such as copper and aluminum, and the insulating layer is generally an insulating varnish. When the motor is running, a large amount of heat will be generated when the enameled wire winding passes through the current. As the heat increases, the insulation layer will break down, the winding will short-circuit, and the motor will burn. The conductor will also generate current loss in a high temperature environment, affecting the conversion energy efficiency and motor performance. Based on this, the prior art proposes a hollow conductor enameled copper round wire, which intends to increase the surface area of ​​the conductor so that the skin effect occurs when the alternating current passes through the conductor, thereby reducing the temperature rise and loss during the energy conversion process of the motor winding, and obtaining better efficiency and performance. However, the commonly used wire diameters of enameled wires are 0.02, 0.08, 0.14, 0.20, 0.25, 0.31 and 0.38 mm respectively; processing copper round wires of these sizes into hollow conductors is difficult to achieve in the existing process; moreover, hollow conductors are easily broken during winding, affecting their mechanical properties; what's more, increasing the surface area of ​​the conductor will make it more likely that the insulation layer will be punctured. Summary of the invention

[0007] Based on this, it is necessary to provide a composite enameled round copper wire to address the technical problem of how to improve the product performance of the enameled round copper wire.

[0008] A composite enameled copper round wire comprises: a steel core layer, a copper cladding layer, a main insulating layer and a surface layer; the copper cladding layer is evenly covered on the outside of the steel core layer, the surface of the copper cladding layer is coated with the main insulating layer, and the surface layer is covered on the outside of the main insulating layer; the steel core layer is composed of steel, the copper cladding layer is composed of copper, the main insulating layer is composed of a polyurethane paint surface layer prepared by using modified polyester resin and blocked isocyanate resin as basic components and then using an organic solvent in a preset proportion, and the surface layer is a polyamide resin paint surface layer.

[0009] Furthermore, the modified polyester resin in the main insulating layer includes: terephthalic acid, neopentyl glycol, p-toluenesulfonic acid, trishydroxyethyl isocyanurate, phthalic anhydride, adipic acid and glycerol.

[0010] Furthermore, the modified polyester resin in the main insulating layer includes: terephthalic acid, neopentyl glycol, sulfuric acid, trihydroxyethyl isocyanurate, phthalic anhydride, adipic acid and glycerol.

[0011] Furthermore, the components of the blocked isocyanate resin in the main insulating layer include: diisocyanate, phenol, ethylene glycol, cyclohexanone, glycerol, cresol and xylene.

[0012] Furthermore, the mixing solvent for mixing the modified polyester resin and the blocked isocyanate resin includes: m-p-cresol, xylene and cyclohexanone.

[0013] Furthermore, the components of the polyamide resin paint surface layer in the surface layer include: tricarboxylic acid anhydride, diphenylmethane diisocyanate, N-methyl-2-pyrrolidone and xylene.

[0014] Furthermore, in a method for preparing the composite enameled copper round wire as described above, the method of coating the copper coating layer on the steel core layer comprises the following steps: S11: Melting the oxygen-free copper rod under the action of the medium frequency induction heating furnace, raising the temperature to a preset temperature and then keeping it warm; S12: Pull the steel wire out from the pay-off drum, and use a stripping wheel to scrape off the oxide layer on the surface of the steel wire. Then, use a straightening machine to straighten the steel wire. S13: Acid and alkali milling is used to remove the oxide layer and oil stains on the surface of the steel wire, and then the surface of the steel wire is washed with water; S14: After washing with water, the surface of the steel wire is dried using a preheating device to remove moisture on the surface, and then nitrogen is introduced through a gas protection device to protect the steel wire; S15: Control the stopper rod in the medium frequency induction furnace to discharge the molten copper, start the traction machine while the stopper rod is raised, wait for the traction rod provided in the traction machine to start to move slowly, the molten copper solidifies after contacting the traction rod, and the copper-clad steel wire is pulled out under the action of the traction force, and then, the traction parameters are adjusted in real time so that the copper-clad steel wire is pulled out reasonably; S16: Wind the copper clad steel wire into a take-up reel.

[0015] In summary, the composite enameled copper round wire of the present invention comprises a steel core layer, a copper cladding layer, a main insulating layer and a surface layer; the copper cladding layer is evenly covered on the outside of the steel core layer, the main insulating layer is coated on the surface of the copper cladding layer, and the surface layer is covered on the outside of the main insulating layer; the steel core layer is composed of steel, the copper cladding layer is composed of copper, the main insulating layer is composed of a polyurethane paint surface layer prepared by using modified polyester resin and blocked isocyanate resin as basic components and then using organic solvents in a preset proportion, and the surface layer is a polyamide resin paint surface layer. The present invention proposes a method of placing steel in the core as a matrix, and concentrically, evenly and continuously coating a copper layer of a certain thickness on its surface, so that copper and steel are firmly combined together to form a matrix of a copper-clad steel bimetallic wire, which has both the excellent electrical properties and corrosion resistance of copper and the high strength of steel. In addition, two polymer insulating materials with different properties are sequentially coated on the surface of the round copper conductor, which can not only enhance the insulation effect of the wire, but also further enhance the corrosion resistance and fatigue strength of the wire; thereby, the various properties of the enameled round copper wire are fully improved. Therefore, the composite enameled round copper wire of the present invention solves the technical problem of how to improve the product performance of the enameled round copper wire. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 This is a schematic diagram of the cross-sectional structure of a composite enameled round copper wire of the present invention; Figure 2 The present invention is a schematic diagram of the equipment layout of a copper-clad steel process for composite enameled round copper wire. DETAILED DESCRIPTION

[0016] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0017] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0018] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0019] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0020] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0021] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0022] For details, please refer to Figure 1The present invention discloses a composite enameled copper round wire, comprising: a steel core layer 101, a copper cladding layer 102, a main insulating layer 103 and a surface layer 104; the copper cladding layer 102 is evenly covered on the outside of the steel core layer 101, the main insulating layer 103 is coated on the surface of the copper cladding layer 102, and the surface layer 104 is covered on the outside of the main insulating layer 103; the steel core layer 101 is composed of steel, the copper cladding layer 102 is composed of copper, the main insulating layer 103 is composed of a polyurethane paint surface layer prepared by using modified polyester resin and blocked isocyanate resin as basic components and then using an organic solvent in a preset ratio, and the surface layer 104 is a polyamide resin paint surface layer.

[0023] Specifically, in a specific embodiment of a composite enameled copper round wire of the present invention, the material of the steel core layer 101 can be Q195 steel wire or similar copper material, and the copper cladding layer 102 can be T1 copper tube or similar copper material.

[0024] Furthermore, in the main insulating layer 103, the components of the modified polyester resin include, by mass, 1-1.5 parts of terephthalic acid, 3-5 parts of neopentyl glycol, 0.03-0.045 parts of p-toluenesulfonic acid, 3.5-5.5 parts of trihydroxyethyl isocyanurate, 1-2 parts of phthalic anhydride, 0.5-1 parts of adipic acid and 3-5 parts of glycerol.

[0025] Another embodiment of the components of the modified polyester resin is: 1-1.2 parts of terephthalic acid, 3-4.5 parts of neopentyl glycol, 0.03-0.04 parts of sulfuric acid, 3.3-5.2 parts of trihydroxyethyl isocyanurate, 0.8-1.5 parts of phthalic anhydride, 0.4-0.8 parts of adipic acid and 3.5-5.5 parts of glycerol.

[0026] Furthermore, in one embodiment, in the main insulating layer 103, the components of the blocked isocyanate resin include, by mass: 5-6 parts of diisocyanate, 1-1.2 parts of phenol, 0.5-0.75 parts of ethylene glycol, 2-3 parts of cyclohexanone, 1-1.5 parts of glycerol, 1-1.5 parts of cresol and 0.5-0.65 parts of xylene.

[0027] Furthermore, the mixing solvent when the modified polyester resin and the blocked isocyanate resin are mixed is a mixed solvent composed of m-cresol, xylene and cyclohexanone in a preset proportion. When the three are mixed, the system temperature is controlled between 70 and 80° C. for 3-5 hours.

[0028] Furthermore, in one embodiment, the components of the polyamide resin paint surface layer include, by weight: 1-2.5 parts of tricarboxylic acid anhydride, 5-9 parts of diphenylmethane diisocyanate, 10-12 parts of N-methyl-2-pyrrolidone, and 12-14 parts of xylene.

[0029] For details, please refer to Figure 2 As shown in 2, the parts arranged from left to right include: a pay-off drum 1, a steel wire 2, a peeling wheel 3, a straightener 4, an acid and alkali washing tank 5, a water washing tank 6, a preheating device 7, a gas protection device 8, a medium frequency induction furnace 9, a crystallizer 10, a traction machine 11, a copper-clad steel wire 12 and a take-up drum 13; Based on this, a process for combining a steel core layer 101 and a copper coating layer 102 in a composite enameled copper round wire of the present invention includes the following steps: S11: melting the oxygen-free copper rod under the action of the medium frequency induction heating furnace 9, raising the temperature to a preset temperature and then keeping it warm; S12: pulling the steel wire 2 out of the pay-off drum 1, and using the peeling wheel 3 to scrape off the oxide layer on the surface of the steel wire 2, and then using the straightening machine 4 to straighten the steel wire 2; S13: using acid and alkali milling groove 5 to remove the oxide layer and oil stains on the surface of the steel wire 2, and then washing the surface of the steel wire 2 with water; S14: After washing, the surface of the steel wire 2 is dried using the preheating device 7 to remove moisture from the surface, and then nitrogen is introduced through the gas protection device 8 to protect the steel wire 2; S15: Control the stopper rod in the medium frequency induction furnace 9 to discharge the molten copper, start the traction machine 11 while the stopper rod is raised, wait for the traction rod (not shown) provided in the traction machine 11 to start to move slowly, the molten copper solidifies after contacting the traction rod, and the copper clad steel wire 12 is pulled out under the action of the traction force, and then the traction parameters are adjusted in real time to be pulled out reasonably; S16: The copper clad steel wire 12 is rolled up in the take-up drum 13 so that the copper cladding layer 102 is covered and connected to the surface of the steel core layer 101 .

[0030] Furthermore, the synthesis method of the modified polyester resin comprises the following steps: S21: adding terephthalic acid, neopentyl glycol and a catalyst of p-toluenesulfonic acid or sulfuric acid in a preset ratio into a reaction kettle, and continuing the reaction at a temperature of 180° C. to 190° C. for 3 to 4 hours. When the system becomes clear and transparent, cooling to room temperature is performed to obtain a mixed diol; S22: Add a preset ratio of mixed diols, trihydroxyethyl isocyanurate, phthalic anhydride, adipic acid, glycerol, xylene and a catalyst of p-toluenesulfonic acid or sulfuric acid into another reaction kettle, and maintain the temperature at 160°C to 180°C for 5-6 hours; then, raise the system temperature to 180°C to 195°C and react for 3 hours, remove the water-carrying agent xylene in the system under vacuum, add a preset amount of m-cresol and cyclohexanone, and stir for 30 minutes to obtain a modified polyester resin liquid.

[0031] Furthermore, the synthesis method of the blocked isocyanate resin comprises the following steps: S31: putting all the pre-prepared diisocyanate and phenol into a reaction kettle, heating and raising the temperature, and controlling the temperature not to exceed 100° C.; S32: After the phenol is completely dissolved, stirring is started in the reactor, and the temperature is continued to rise to 130±3°C, and the temperature is maintained for 4 hours; S33: cooling the temperature in the reactor to less than 100° C., then adding a quarter of the pre-prepared cyclohexanone into the reactor; at the same time, mixing the pre-prepared glycerin, ethylene glycol and a quarter of the pre-prepared cyclohexanone to form a mixed solution; and adding the mixed solution into the reactor, controlling the reaction temperature not to exceed 110° C., and continuing for 30 minutes; S34: flush the header tank with one quarter of the cyclohexanone prepared in advance and put it into the reactor; S35: stopping heating the reactor, and sequentially adding m-p-cresol, xylene, and the remaining one-quarter of the pre-prepared cyclohexanone; starting stirring in the reactor, and controlling the stirring time to be no less than 30 minutes; S36: After the temperature of the reaction kettle is lower than 60° C., the material is discharged and filtered to obtain a blocked isocyanate resin liquid.

[0032] Next, after preparing a mixed solvent with para-cresol, xylene and cyclohexanone according to a preset ratio, the modified polyester resin liquid, the blocked isocyanate resin liquid and the mixed solvent are mixed; the reaction temperature is controlled to be 70 to 80°C, and the reaction is continued for 3-5 hours to obtain the finished lacquer liquid of the main insulating layer 103; then, the copper-clad steel wire 12 is coated with the finished lacquer liquid on the surface of the copper-clad layer 102 according to the felt method using an enamelling machine; thereby, the main insulating layer 102 is coated and connected to the surface of the copper-clad layer 102.

[0033] Furthermore, the synthesis method of the surface layer 104, i.e. the polyamide resin paint surface layer, comprises the following steps: S41: according to a preset ratio, N-methyl-2-pyrrolidone and xylene are added into a reaction kettle, mixed and heated; S42: When the temperature in the reaction kettle reaches 80° C., add tricarboxylic acid anhydride and diphenylmethane diisocyanate accounting for half of the total amount, heat the materials in the kettle to 90° C., and allow to react for 2 hours; S43: After adding the remaining half of diphenylmethane diisocyanate, the temperature of the materials in the reactor is raised to 120°C. When the viscosity of the polycondensate in the reactor reaches 10000mPa·s and 30°C, the heating is stopped and dimethylacetamide is added as a solvent to obtain a polyamide resin paint.

[0034] Next, the polyamide resin varnish is coated on the outside of the main insulating layer 102 using an enamelling machine, thereby obtaining the composite enameled round copper wire of the present invention.

[0035] In summary, the composite enameled copper round wire of the present invention comprises a steel core layer 101, a copper cladding layer 102, a main insulating layer 103 and a surface layer 104; the copper cladding layer 102 is evenly covered on the outside of the steel core layer 101, the main insulating layer 103 is coated on the surface of the copper cladding layer 102, and the surface layer 104 is covered on the outside of the main insulating layer 103; the steel core layer 101 is composed of steel, the copper cladding layer 102 is composed of copper, the main insulating layer 103 is composed of a polyurethane paint surface layer prepared by using modified polyester resin and blocked isocyanate resin as basic components and then using organic solvent in a preset proportion, and the surface layer 104 is a polyamide resin paint surface layer. The present invention proposes a method of placing steel in the core as a matrix, and concentrically, evenly and continuously coating a copper layer of a certain thickness on its surface, so that copper and steel are firmly combined to form a matrix of a copper-clad steel bimetallic wire, which has both the excellent electrical properties and corrosion resistance of copper and the high strength of steel. In addition, two polymer insulating materials with different properties are sequentially coated on the surface of the round copper conductor, which can not only enhance the insulation effect of the wire, but also further enhance the corrosion resistance and fatigue strength of the wire; thereby, the various properties of the enameled round copper wire are fully improved. Therefore, the composite enameled round copper wire of the present invention solves the technical problem of how to improve the product performance of the enameled round copper wire.

[0036] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0037] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A composite enameled round copper wire, characterized in that: It includes: Steel Core layer, copper cladding layer, main insulation layer and surface layer; A copper cladding layer is uniformly arranged outside the steel core layer, a main insulating layer is coated on the surface of the copper cladding layer, and a surface layer is arranged outside the main insulating layer; the steel core layer is composed of steel, the copper cladding layer is composed of copper, the main insulating layer is composed of a polyurethane paint surface layer prepared by using modified polyester resin and blocked isocyanate resin as basic components and then using organic solvents in a preset proportion, that is, the surface layer is a polyamide resin paint surface layer.

2. The composite enameled round copper wire according to claim 1, characterized in that: The modified polyester resin in the main insulating layer comprises terephthalic acid, neopentyl glycol, p-toluenesulfonic acid, trishydroxyethyl isocyanurate, phthalic anhydride, adipic acid and glycerol.

3. The composite enameled round copper wire according to claim 1, characterized in that: The modified polyester resin in the main insulating layer comprises terephthalic acid, neopentyl glycol, sulfuric acid, trihydroxyethyl isocyanurate, phthalic anhydride, adipic acid and glycerol.

4. The composite enameled round copper wire according to claim 1, characterized in that: The components of the blocked isocyanate resin in the main insulating layer include: diisocyanate, phenol, ethylene glycol, cyclohexanone, glycerol, cresol and xylene.

5. The composite enameled round copper wire according to claim 1, characterized in that: The mixing solvents for mixing the modified polyester resin and the blocked isocyanate resin include: m-p-cresol, xylene and cyclohexanone.

6. The composite enameled round copper wire according to claim 1, characterized in that: That is, the components of the polyamide resin paint surface layer in the surface layer include: tricarboxylic acid anhydride, diphenylmethane diisocyanate, N-methyl-2-pyrrolidone and xylene.

7. A method for preparing a composite enameled round copper wire as claimed in any one of claims 1 to 6, characterized in that: The method of coating the copper cladding layer on the steel core layer comprises the following steps: S11: Melting the oxygen-free copper rod under the action of the medium frequency induction heating furnace, raising the temperature to a preset temperature and then keeping it warm; S12: Pull the steel wire out from the pay-off drum, and use a stripping wheel to scrape off the oxide layer on the surface of the steel wire. Then, use a straightening machine to straighten the steel wire. S13: Acid and alkali milling is used to remove the oxide layer and oil stains on the surface of the steel wire, and then the surface of the steel wire is washed with water; S14: After washing with water, the surface of the steel wire is dried using a preheating device to remove moisture on the surface, and then nitrogen is introduced through a gas protection device to protect the steel wire; S15: Control the stopper rod in the medium frequency induction furnace to discharge the molten copper, start the traction machine while the stopper rod is raised, wait for the traction rod provided in the traction machine to start to move slowly, the molten copper solidifies after contacting the traction rod, and the copper-clad steel wire is pulled out under the action of the traction force, and then, the traction parameters are adjusted in real time so that the copper-clad steel wire is pulled out reasonably; S16: Wind the copper clad steel wire into a take-up reel.

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