A heat-resistant self-lubricating insulating coating for electromagnetic wire with high wear resistance, and a preparation method and application thereof

Abstract

The application discloses a heat-resistant self-lubricating electromagnetic wire insulating paint with high wear resistance and a preparation method and application thereof. The electromagnetic wire insulating paint is prepared from the following raw materials: N-methyl pyrrolidone, dimethylformamide, dimethylbenzene, polyamide-imide, ultra-high molecular weight polyethylene micro powder, graphene, oxidized polyethylene wax, silicone modified siloxane and hyperdispersant. The heat resistance of the prepared heat-resistant self-lubricating electromagnetic wire coating material reaches C level (220 DEG C), the wear resistance is obviously improved, the friction coefficient is lower, the paint film damage in the winding coil processing and shaping process is greatly reduced, the manufacturing quality of the coil winding is improved, the finished paint quality is stable, and the finished paint has good film forming performance. The prepared finished product and the finished electromagnetic wire produced by the finished product have good product performance.

Description

Technical Field

[0001] This invention belongs to the field of insulating coatings for electromagnetic wires, specifically relating to a heat-resistant, self-lubricating insulating coating for electromagnetic wires with high wear resistance, its preparation method, and its application. Background Technology

[0002] In addition to ideal electrical insulation properties, the coating of electromagnetic wire must also have good wear resistance and mechanical properties to meet the increasingly stringent requirements of coil processing (assessing the coating performance and friction coefficient of electromagnetic wire). Otherwise, it will lead to the damage of the coating film during the processing of electromagnetic wire coil, causing mechanical defects such as pinholes, cracks, and peeling, which will significantly reduce the electrical insulation performance and even cause the coil insulation to short-circuit and become unusable.

[0003] The good wear resistance of a coating film is mainly determined by its molecular structure, hardness, toughness, and surface friction coefficient. Among traditional electromagnetic wire insulation coatings, polyurethane and acetal coatings exhibit good wear resistance but poor heat resistance (<180℃). Polyamide-imide coatings, due to their larger molecular weight, do not have excellent wear resistance and are inferior to polyurethane and acetal coatings. Polyester series, polyesterimide, and polyimide coatings generally have only moderate wear resistance.

[0004] Therefore, it is of great practical significance to develop electromagnetic wire coating materials with high heat resistance (220℃), excellent wear resistance and self-lubricating properties, especially for winding manufacturing under harsh coil processing conditions, such as compact electrical windings such as drive motor coils, disc motor coils, and power tool coils. The wire surface coating material must have excellent wear resistance. Summary of the Invention

[0005] Purpose of the invention: To address the problems existing in the prior art, this invention provides a novel electromagnetic wire coating material with excellent wear resistance and high heat resistance (≥220℃) and self-lubricating properties, in order to meet the stringent technical requirements of increasingly high-speed and high-order-precision electrical winding processing. It effectively solves the problem of poor heat resistance in electromagnetic wire insulating coatings, while ensuring that the coil has high forming size requirements and sufficient mechanical properties during high-speed winding.

[0006] The present invention also provides a method for preparing and applying the heat-resistant self-lubricating insulating coating for electromagnetic wire with high wear resistance.

[0007] Technical solution: To achieve the above objectives, the present invention provides a heat-resistant, self-lubricating insulating coating for electromagnetic wires with high wear resistance, comprising the following raw materials in parts by weight:

[0008] 13–54 parts N-methylpyrrolidone, 27 parts dimethylformamide, 27–54 parts xylene, 797–897 parts polyamide-imide, 5.7–16 parts ultra-high molecular weight polyethylene micro powder, 10–15 parts graphene, 3.1–5.6 parts oxidized polyethylene wax, 1.57–4.2 parts organosilicon-modified siloxane, and 15.7–31 parts superdispersant.

[0009] The polyamide-imide resin has a solid content of 30-35%. Preferably, the polyamide-imide resin (PAI) is 1990ZGX35 (35% solid content) produced by Changzhou IVA Electrical Insulation Materials Co., Ltd.

[0010] The ultra-high molecular weight polyethylene (UHMW-PE) micropowder has a molecular weight of linear polyethylene with an average molecular weight exceeding 1.5 million. Preferably, the UHMW-PE micropowder is the MIPELON (25-30 μm) product from Mitsui Chemicals, Japan. This invention uses UHMW-PE micropowder to improve and enhance the wear resistance of polyamide-imide paint.

[0011] The graphene is a graphene dispersion. Preferably, the graphene is a high-quality thin-layer graphene dispersion (model: GRF-FLGOD-01) from Suzhou Greifong Nanotechnology Co., Ltd.

[0012] The oxidized polyethylene wax is a nano-sized synthetic wax. Preferably, the oxidized polyethylene wax (OPE) is a nano-sized synthetic wax (average particle size 40-100nm), and the model is W-205 (Shanghai Tongshi Technology Co., Ltd.).

[0013] The organosilicon-modified siloxane is a polyester-modified organosilicon-modified siloxane. Preferably, the organosilicon-modified siloxane is polyester-modified, such as BYK-300 from BYK Corporation. This invention adds a certain proportion of synthetic waxes (OPE waxes) and organosilicon-modified siloxanes (BYK-300) to improve the surface quality of the coating film and further reduce the coefficient of friction.

[0014] The superdispersant is an oil-based superdispersant, including polyester, polyether, and polyacrylate types; preferably, it is Lubrizol (Germany) SOLSPERSE 24000SC superdispersant. The use of a superdispersant improves the dispersion of ultra-high molecular weight polyethylene powder in polyamide-imide paint and establishes good storage stability.

[0015] The method for preparing the heat-resistant, self-lubricating insulating coating for electromagnetic wires with high wear resistance according to the present invention includes the following steps:

[0016] (1) Take N-methylpyrrolidone, dimethylformamide and xylene by weight and stir them evenly at room temperature to prepare mixed solvent A;

[0017] (2) In mixed solvent A, ultra-high molecular weight polyethylene micro powder, graphene and super dispersant are added in sequence, stirred evenly, and then oxidized polyethylene wax is added and stirred evenly to obtain semi-finished product B.

[0018] (3) Grind the semi-finished product B until it becomes a uniform slurry C.

[0019] (4) Take polyamide imide and semi-finished product C by weight, then add organosilicon-modified siloxane, stir at high speed to disperse evenly, and obtain the finished liquid product;

[0020] (5) The finished liquid obtained above is filtered and packaged to obtain the finished product.

[0021] The high-speed stirring in step (4) is high-speed stirring at 1200-1500 rpm for 2-3 hours.

[0022] The present invention relates to the application of the heat-resistant, self-lubricating insulating coating for electromagnetic wire with high wear resistance in coil processing.

[0023] Currently, insulating coatings for electromagnetic wires largely employ the method of using wear-resistant enameled wire varnishes, primarily by adding tetrafluoroethylene (PTFE) or inorganic nanomaterials to improve the wear resistance of the enameled wire. This invention prepares a novel polyamide-imide varnish with excellent wear resistance, self-lubricating properties, and good heat resistance. The finished product is stable during storage, and its technical performance meets usage requirements. This invention first uses ultra-high molecular weight polyethylene (UHMW-PE) micropowder to improve the wear resistance of the PAI varnish film. UHMW-PE is a linear polymer material, referring to linear polyethylene with an average molecular weight exceeding 1.5 million. It combines the superior properties of most polymer materials, with high wear resistance being its main outstanding performance, even surpassing some alloy materials. It is 4 to 6 times that of steel and stainless steel, possesses a low coefficient of friction (0.07), excellent electrical properties (50 KV / mm), a low dielectric constant (2.3), and resistance to chemical corrosion. This technical solution significantly improves the wear resistance of the PAI varnish film by adding ultra-high molecular weight polyethylene.

[0024] Meanwhile, the present invention uses a super-dispersant to significantly improve the dispersion effect of ultra-high molecular weight polyethylene micro powder in PAI paint, ensuring the homogeneity and storage stability of the finished paint solution; and the use of high-quality polyester-based organosilicon-modified siloxane improves the smoothness and uniformity of the film and reduces electrical pinholes.

[0025] Furthermore, by using oxidized polyethylene wax with good solubility and compatibility with PAI, the coefficient of friction of the paint film is further reduced, giving it self-lubricating properties and improving the wear resistance of the paint film surface.

[0026] Furthermore, graphene, a two-dimensional crystal, possesses unique electrical, mechanical, thermal, and optical properties due to its unique structure. The addition of graphene provides self-healing properties: graphene nanoparticles can fill wear micropores and scratches, repairing the surfaces of friction pairs; simultaneously, it forms a lubricating protective film: graphene nanoparticles form "ball bearings" on the friction surface, exhibiting self-lubricating properties; graphene nanoparticles fill the uneven surfaces of the friction pairs, and the tribochemical reaction forms a stable third body between the friction pairs, increasing wear resistance; the excellent cleaning and dispersing properties of graphene nanoparticles allow the paint to rapidly diffuse and form a film.

[0027] This invention is the first to utilize ultra-high molecular weight polyethylene (UHMWPE) and graphene in combination to manufacture a wear-resistant PAI varnish. It employs UHMWPE, which exhibits excellent wear resistance, and graphene, which reduces the coefficient of friction, and through a unique processing technique, incorporates them into the PAI varnish to obtain a PAI varnish that possesses both good heat resistance and excellent wear resistance. This invention not only significantly reduces the surface friction coefficient of PAI-coated wires and improves wear resistance, but also uses a super-dispersant to disperse the above materials, resulting in a homogeneous and stable modified PAI varnish.

[0028] Beneficial effects: Compared with the prior art, the advantages of the present invention are as follows:

[0029] This invention prepares a wear-resistant, self-lubricating, heat-resistant electromagnetic wire coating material with heat resistance reaching Class C (220℃). Compared with traditional polyamide-imide varnishes, it exhibits significantly improved wear resistance and a lower coefficient of friction, greatly reducing varnish film damage during coil processing and shaping, improving the manufacturing quality of coil windings, and ensuring stable finished varnish quality with excellent film-forming properties. Both the finished product prepared by this invention and the finished electromagnetic wires produced using this method demonstrate excellent product performance. Detailed Implementation

[0030] The present invention will be further described below with reference to the scheme and embodiments.

[0031] All raw materials and reagents used in the examples are commercially available. Seed cells were obtained using existing conventional separation and purification methods or directly from commercially available sources.

[0032] The following raw materials were specifically used in the examples:

[0033] The polyamide-imide resin (PAI) used is 1990ZGX35 (35% solid content) produced by Changzhou IVA Electrical Insulation Materials Co., Ltd.

[0034] Ultra-high molecular weight polyethylene micro powder (UHMW-PE) is a product of MIPELON (25-30μm) from Mitsui Chemicals, Japan.

[0035] The graphene is a high-quality thin-layer graphene dispersion (model: GRF-FLGOD-01) from Suzhou Greifong Nanotechnology Co., Ltd.

[0036] Oxidized polyethylene wax (OPE) is a nano-sized (average particle size 40-100nm) synthetic wax, model W-205 (Shanghai Tongshi Technology Co., Ltd.).

[0037] The organosilicon-modified siloxane is BYK-300 from BYK Corporation.

[0038] The superdispersant is Lubrizol (Germany) SOLSPERSE 24000SC superdispersant.

[0039] Example 1

[0040] Calculate according to the weight parts of each substance in each step.

[0041] Step a: Take 13 parts of NMP (N-methylpyrrolidone), 27 parts of dimethylformamide, and 27 parts of xylene and add them to the reaction vessel. Stir and mix evenly at room temperature to obtain mixed solvent A.

[0042] Step b: In mixed solvent A, add 5.7 parts of ultra-high molecular weight polyethylene micro powder, 10 parts of graphene, and 15.7 parts of superdispersant in sequence, stir evenly, then add 3.1 parts of oxidized polyethylene wax (OPE wax), stir evenly to obtain semi-finished product B.

[0043] Step c: Put the semi-finished product B into a ball mill for grinding until the fineness is ≤6μm, until it becomes a uniform slurry C.

[0044] Step d: Take 897 parts of polyamide-imide (PAI) and put it into a high-speed disperser. At the same time, add the semi-finished product C obtained in step c, and then add 1.57 parts of organosilicon-modified siloxane. Stir at high speed at 1500 rpm for 2 hours to disperse evenly and obtain the finished liquid.

[0045] Step e: After filtering the above-obtained finished product through a 250-mesh filter, test its viscosity / solid content. If it meets the requirements, proceed with packaging the finished product.

[0046] Example 2

[0047] Calculate according to the weight parts of each substance in each step.

[0048] Step a: Take 27 parts of NMP (N-methylpyrrolidone), 27 parts of dimethylformamide, and 36 parts of xylene and add them to the reaction vessel. Stir and mix evenly at room temperature to obtain mixed solvent A.

[0049] Step b: In mixed solvent A, add 9 parts of ultra-high molecular weight polyethylene micro powder, 12 parts of graphene, and 21 parts of superdispersant in sequence, stir evenly, then add 4.5 parts of oxidized polyethylene wax (OPE wax), stir evenly to obtain semi-finished product B.

[0050] Step c: Put the semi-finished product B into a ball mill for grinding until the fineness is ≤6μm, until it becomes a uniform slurry C.

[0051] Step d: Take 860 parts of polyamide-imide (PAI) and put it into a high-speed disperser. At the same time, add the semi-finished product C obtained in step c, and then add 3.4 parts of organosilicon-modified siloxane. Stir at high speed at 1200 rpm for 3 hours to disperse evenly and obtain the finished liquid.

[0052] Step e: Test the viscosity / solid content of the finished product obtained above, and filter it through a 250-mesh filter before packaging to obtain the finished product.

[0053] Example 3

[0054] Calculate according to the weight parts of each substance in each step.

[0055] Step a: Take 54 parts by weight of NMP (N-methylpyrrolidone), 27 parts by weight of dimethylformamide, and 54 parts by weight of xylene and add them to the reaction vessel. Stir and mix evenly at room temperature to obtain mixed solvent A.

[0056] Step b: In mixed solvent A, add 16 parts of ultra-high molecular weight polyethylene micro powder, 15 parts of graphene, and 31 parts of superdispersant in sequence, stir evenly, then add 5.6 parts of oxidized polyethylene wax (OPE wax), stir evenly to obtain semi-finished product B.

[0057] Step c: Put the semi-finished product B into a ball mill for grinding until the fineness is ≤6μm, until it becomes a uniform slurry C.

[0058] Step d: Take 797 parts by weight of polyamide-imide (PAI) and put it into a high-speed disperser. At the same time, add the semi-finished product C obtained in step c, and then add 4.2 parts of organosilicon-modified siloxane. Stir at high speed at 1500 rpm for 2.5 h to disperse evenly and obtain the finished liquid product.

[0059] Step e: Test the viscosity / solid content of the finished product obtained above, and filter it through a 350-mesh filter before packaging to obtain the finished product.

[0060] Experimental Example 1

[0061] The high-wear-resistant, heat-resistant, self-lubricating electromagnetic wires prepared using the insulating coatings of Examples 1-3 of this invention were coated with enameled wires using enameling machines and tested. The results were compared with those of electromagnetic wires coated with pure polyamide-imide varnish (PAI varnish) under the same conditions (Comparative Examples 1-5). The performance data are shown in Tables 1 and 2 according to the standard GB / T4074 winding wire test method.

[0062] Comparative Example 1 used pure polyamide-imide varnish (PAI varnish).

[0063] Comparative Example 2 uses the same preparation method as Example 2, except that ultra-high molecular weight polyethylene micro powder is not added, and a coating is prepared accordingly.

[0064] Comparative Example 3 uses the preparation method of Example 2, except that no superdispersant is added, and a coating is prepared.

[0065] Comparative Example 4 uses the preparation method of Example 2, except that oxidized polyethylene wax is not added, and a coating is prepared accordingly.

[0066] Comparative Example 5 uses the preparation method of Example 2, except that graphene is not added, and a coating is prepared.

[0067] Table 1

[0068]

[0069]

[0070] *Electrode wire specifications: 220 grade polyamide-imide enameled round copper wire QXY-2 / 0.690mm.

[0071] Table 2

[0072]

[0073] *Electrode wire specifications: 220 grade polyamide-imide enameled round copper wire QXY-2 / 0.690mm.

[0074] As can be seen from the test results in Tables 1 and 2, the electromagnetic wire coated with the above embodiments of the present invention has a lower static friction coefficient and higher scratch-resistant coating (wear resistance) performance than conventional PAI paint, and other electrical properties are maintained well. At the same time, it can maintain high heat resistance (≥220℃). It is a new type of electromagnetic wire coating material with excellent wear resistance and self-lubricating properties.

Claims

1. An insulating coating for heat-resistant, self-lubricating electromagnetic wires with high wear resistance, characterized in that, Made from the following raw materials in parts by weight: 13-54 parts of N-methylpyrrolidone, 27 parts of dimethylformamide, 27-54 parts of xylene, 797-897 parts of polyamide-imide, 5.7-16 parts of ultra-high molecular weight polyethylene micro powder, 10-15 parts of graphene, 3.1-5.6 parts of oxidized polyethylene wax, 1.57-4.2 parts of organosilicon-modified siloxane, and 15.7-31 parts of superdispersant; The ultra-high molecular weight polyethylene micro powder has a molecular weight of linear polyethylene with an average molecular weight of over 1.5 million; the linear polyethylene is ultra-high molecular weight polyethylene, specifically MIPELON from Mitsui Chemicals, Japan, with a molecular weight of 25~30μm. The graphene is a graphene dispersion; the graphene dispersion is a high-quality thin-layer graphene dispersion from Suzhou Greenford Nanotechnology Co., Ltd., model GRF-FLGOD-01.

2. The insulating coating for heat-resistant, self-lubricating electromagnetic wire with high wear resistance according to claim 1, characterized in that, The solids content of the polyamide-imide resin is 30-35%.

3. The insulating coating for heat-resistant, self-lubricating electromagnetic wire with high wear resistance according to claim 1, characterized in that, The oxidized polyethylene wax is a nanoscale synthetic wax with an average particle size of 40~100nm.

4. The insulating coating for heat-resistant, self-lubricating electromagnetic wire with high wear resistance according to claim 1, characterized in that, The organosilicon-modified siloxane is a polyester-modified organosilicon-modified siloxane.

5. The insulating coating for heat-resistant, self-lubricating electromagnetic wire with high wear resistance according to claim 1, characterized in that, The superdispersant is a polyester-type oily superdispersant.

6. A method for preparing an insulating coating for heat-resistant, self-lubricating electromagnetic wire with high wear resistance as described in claim 1, characterized in that, Includes the following steps: (1) Take N-methylpyrrolidone, dimethylformamide and xylene by weight and stir and mix them evenly at room temperature to prepare mixed solvent A; (2) In mixed solvent A, ultra-high molecular weight polyethylene micro powder, graphene and super dispersant are added in sequence and stirred evenly. Then, oxidized polyethylene wax is added and stirred evenly to obtain semi-finished product B. (3) Grind the semi-finished product B until it becomes a uniform slurry C; (4) Take polyamide-imide and uniform slurry C by weight, then add organosilicon-modified siloxane, stir at high speed to disperse evenly, and obtain the finished liquid product; (5) The finished liquid obtained above is filtered and packaged to obtain the finished product.

7. The method for preparing the heat-resistant, self-lubricating insulating coating for electromagnetic wire with high wear resistance according to claim 6, characterized in that, The high-speed stirring in step (4) is high-speed stirring at 1200~1500 rpm for 2~3 hours.

8. The application of the heat-resistant self-lubricating electromagnetic wire insulating coating with high wear resistance as described in claim 1 in coil processing.

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