阅读说明：本技术 一种微电机用铝基磁线及其制备方法 (Aluminum-based magnetic wire for micromotor and preparation method thereof ) 是由 曾东文 左劲松 郑守国 陈光宝 于 2021-06-28 设计创作，主要内容包括：本发明公开了一种微电机用铝基磁线及其制备方法,通过将三羟甲基丙烷加入至醋酸丁酯中搅拌分散,之后加入二苯基甲烷二异氰酸酯和亚磷酸三甲苯酯,继续搅拌反应,反应完全后加入增强填料继续搅拌分散,得到绝缘漆,将铝芯导线涂上绝缘漆,之后进行漆膜固化处理,且处理后的铝芯导线冷却至室温后,收线后即得到该微电机用铝基磁线；通过提高聚氨酯线的绝缘厚度,提高单位截面积的绝缘厚度来提高绝缘电压,抵抗由于漆膜被拉伸导致的耐高压针孔的能力降低,同时通过添加增强填料与聚氨酯树脂固化反应过程中所产生的基团反应,两者之间通过长分子链相结合,使其网状结构更加复杂,进而提高其绝缘性能。(The invention discloses an aluminum-based magnetic wire for a micromotor and a preparation method thereof, trimethylolpropane is added into butyl acetate to be stirred and dispersed, then diphenylmethane diisocyanate and tricresyl phosphite are added to be continuously stirred and reacted, after the reaction is completed, a reinforcing filler is added to be continuously stirred and dispersed to obtain insulating paint, an aluminum core wire is coated with the insulating paint, then paint film solidification treatment is carried out, and after the treated aluminum core wire is cooled to room temperature, a wire is taken up to obtain the aluminum-based magnetic wire for the micromotor; the insulating voltage is improved by improving the insulating thickness of the polyurethane wire and the insulating thickness of the unit sectional area, the capability of resisting high-pressure pin holes caused by the fact that a paint film is stretched is reduced, meanwhile, the reinforcing filler is added to react with groups generated in the curing reaction process of the polyurethane resin, and the reinforcing filler and the polyurethane resin are combined through long molecular chains, so that the net structure of the polyurethane wire is more complex, and the insulating property of the polyurethane wire is improved.)

1. The aluminum-based magnetic wire for the micromotor is characterized by comprising an aluminum core wire and an insulating coating wrapping the aluminum core wire, wherein the insulating coating is formed by curing insulating paint;

the aluminum-based magnet wire for the micromotor is prepared by the following steps:

the method comprises the following steps: adding trimethylolpropane into butyl acetate, stirring and dispersing for 20-40min under the condition that the stirring speed is 1000-2000r/min, then adding diphenylmethane diisocyanate and tricresyl phosphite, continuously stirring and reacting for 2-4h, adding a reinforcing filler after the reaction is completed, and continuously stirring and dispersing for 30-60min to obtain insulating paint;

step two: coating insulating paint on the aluminum core wire, then carrying out paint film curing treatment at the curing temperature of 300-600 ℃, cooling the treated aluminum core wire to room temperature, and taking up wires to obtain the aluminum-based magnetic wire for the micromotor.

2. The aluminum-based magnet wire for micromotors as claimed in claim 1, characterized in that said insulating varnish comprises the following components in parts by weight: 160 parts of trimethylolpropane 140-.

3. An aluminum-based magnet wire for micro-machines according to claim 1, characterized in that said insulating varnish is a light yellow transparent liquid with a solid content of 44-46%.

4. An aluminum-based magnet wire for micromotors as claimed in claim 1, characterized in that said reinforcing filler is prepared by the following process:

a1: adding pyromellitic dianhydride, polyethylene glycol and N, N-dimethylformamide into a three-neck flask provided with a stirrer, a condenser tube and a thermometer, heating to 100 ℃ while stirring at the stirring speed of 300-500r/min, then reacting at constant temperature for 3-5h, cooling a reaction product to room temperature after the reaction is finished, distilling the reaction product under reduced pressure, precipitating and separating the distillation product by using distilled water at the temperature of 60-70 ℃, then placing the precipitate in a vacuum drying box, and drying at the temperature of 60-80 ℃ to constant weight to obtain an intermediate 1;

a2: adding the intermediate 1, pyromellitic dianhydride, N-dimethylformamide, xylene and p-toluenesulfonic acid into a three-neck flask provided with a magnetic stirrer, a condenser pipe, a water separator and a thermometer, stirring and heating to 145 ℃ under the condition of stirring rate of 300-500r/min, then reacting at constant temperature for 5-7h, cooling the reaction product to room temperature after the reaction is finished, then distilling the reaction product under reduced pressure, precipitating and separating the distillation product with methanol, then placing the precipitate in a vacuum drying box, and drying at the temperature of 60-80 ℃ to constant weight to obtain an intermediate 2;

a3: adding deionized water and absolute ethyl alcohol into a three-neck flask provided with a magnetic stirrer, a constant-pressure dropping funnel and a thermometer, dropwise adding ammonia water while stirring at the stirring speed of 100-300r/min, controlling the dropwise adding speed to be 0.5-1mL/min, continuously stirring for 3-5min after the dropwise adding is finished, dropwise adding tetraethyl orthosilicate, controlling the dropwise adding speed to be 2-3 s/drop, continuously stirring for reacting for 4-5h after the dropwise adding is finished, washing a reaction product with deionized water after the reaction is finished, centrifuging to take a lower-layer white solution, placing the lower-layer white solution into a vacuum drying box, and drying at the temperature of 80-90 ℃ to constant weight to obtain nano silicon dioxide;

a4: placing nano silicon dioxide in a vacuum drying box at the temperature of 120-125 ℃ for drying for 10-15min, naturally cooling to room temperature, adding the nano silicon dioxide into a three-neck flask provided with a magnetic stirrer, a constant-pressure dropping funnel and a thermometer, then adding toluene a, carrying out ultrasonic dispersion for 40-60min under the condition that the ultrasonic frequency is 45-65kHz, then adding the intermediate 3 dropwise while stirring under the condition that the stirring speed is 100-300r/min, heating to 110-120 ℃ after dropwise addition, carrying out reflux reaction for 8-10h, cooling a reaction product to room temperature after the reaction is finished, carrying out ultrasonic washing for 2-3 times by using toluene b, centrifuging, placing a precipitate in the vacuum drying box, and drying to constant weight under the temperature of 80-90 ℃ to obtain an intermediate 4;

a5: adding the intermediate 4 and acetone into a three-neck flask provided with a mechanical stirrer and a thermometer, stirring and dispersing for 20-30min under the condition of stirring speed of 800-.

5. The aluminum-based magnetic wire for micromotors as claimed in claim 4, wherein the ratio of the pyromellitic dianhydride, the polyethylene glycol and the N, N-dimethylformamide in step A1 is 0.13 mol: 0.20 mol: 100 and 200 mL.

6. The aluminum-based magnetic wire for micromotors according to claim 4, characterized in that said intermediate 1, pyromellitic dianhydride, N-dimethylformamide, xylene and p-toluenesulfonic acid used in step A2 are used in a ratio of 0.20 mol: 0.12 mol: 100-150 mL: 50-100 mL: 1-10 g.

7. The aluminum-based magnetic wire for the micro-motor as claimed in claim 4, wherein the amount of the deionized water, the absolute ethyl alcohol, the ammonia water and the tetraethyl orthosilicate in the step A3 is 30 mL: 100mL of: 10mL of: 12mL, wherein the mass fraction of the ammonia water is 25-28%.

8. The aluminum-based magnet wire for micromotors as claimed in claim 4, wherein said intermediate body 3 in step A4 is a solution formed by dissolving KH-550 in deionized water, and the mass ratio of said nanosilicon dioxide to KH-550 is 25: 1, the dosage ratio of the nano silicon dioxide to the toluene a is 1 g: 10 mL.

9. An aluminum-based magnetic wire for micro-motors, according to claim 4, characterized in that said intermediate 4, acetone and p-toluenesulfonic acid in step A5 are used in a ratio of 1 g: 20mL of: 0.01-0.05g, the molar ratio of the intermediate 4 to the intermediate 2 is 1.0: 0.2-0.5.

10. The method for preparing an aluminum-based magnet wire for micromotors according to claim 1, characterized in that it comprises the following steps:

the method comprises the following steps: weighing 160 parts of trimethylolpropane 140-one, 900 parts of diphenylmethane diisocyanate 800-one, 1250 parts of butyl acetate 1100-one, 0.390-0.455 part of tricresyl phosphite and 50-100 parts of reinforcing filler for later use;

step two: adding trimethylolpropane into butyl acetate, stirring and dispersing for 20-40min under the condition that the stirring speed is 1000-2000r/min, then adding diphenylmethane diisocyanate and tricresyl phosphite, continuously stirring and reacting for 2-4h, adding a reinforcing filler after the reaction is completed, and continuously stirring and dispersing for 30-60min to obtain insulating paint;

step three: coating insulating paint on the aluminum core wire, then carrying out paint film curing treatment at the curing temperature of 300-600 ℃, cooling the treated aluminum core wire to room temperature, and taking up wires to obtain the aluminum-based magnetic wire for the micromotor.

Technical Field

The invention relates to the technical field of enameled wire manufacturing, in particular to an aluminum-based magnetic wire for a micro motor and a preparation method thereof.

Background

The micromotor is one of important precise electromechanical elements in information society, modern military equipment, process equipment and automatic control systems, and is also an indispensable transmission element in office automation equipment, various vehicles and household appliances; the micromotor industry has the characteristic of modern large-scale production at present, and a polyurethane paint bag is a product widely adopted in the field;

for example, in the research on polyurethane enameled wire lacquer, which is an article in 1993 2 nd 2, the tris- (hydroxyethyl) isocyanurate (SHEIC) is used for modifying the polyurethane enameled wire lacquer, and a heterocycle is introduced into a polyurethane lacquer film, so that an enameled wire has good insulating property and higher softening breakdown temperature, and the characteristic of good direct weldability of the polyurethane lacquer film is kept;

when the micromotor is developed to the present, the requirement on the insulating property of an enameled wire reaches more than 10000V, and the requirement that the high-voltage pin holes are less than or equal to 1/30 m is still kept under the condition that a paint film is stretched by 10% in the high-speed winding process, the breakdown voltage of the existing polyurethane wire in the market is basically below 10KV, and the number of the high-voltage pin holes stretched by 10% reaches more than 20/30 m, so that the requirement of a new technology can not be met;

therefore, a high insulation aluminum-based magnet wire is needed to solve the above problems.

Disclosure of Invention

In order to overcome the technical problems, the invention aims to provide an aluminum-based magnetic wire for a micromotor and a preparation method thereof, wherein the aluminum-based magnetic wire comprises the following steps: the aluminum-based magnetic wire for the micro-motor is obtained by adding trimethylolpropane into butyl acetate, stirring and dispersing, then adding diphenylmethane diisocyanate and tricresyl phosphite, continuing to stir for reaction, adding a reinforcing filler after the reaction is completed, continuing to stir and disperse to obtain an insulating paint, coating the insulating paint on an aluminum core wire, then carrying out paint film curing treatment, cooling the treated aluminum core wire to room temperature, and taking up wires, so that the problems that the breakdown voltage of the existing polyurethane wire is basically below 10KV, the number of high-voltage pin holes after 10% stretching reaches 20/30 m, and the requirements of new technologies can not be met far are solved.

The purpose of the invention can be realized by the following technical scheme:

an aluminum-based magnetic wire for a micromotor comprises an aluminum-core wire and an insulating coating wrapping the aluminum-core wire, wherein the insulating coating is formed by curing insulating paint;

the aluminum-based magnet wire for the micromotor is prepared by the following steps:

the method comprises the following steps: adding trimethylolpropane into butyl acetate, stirring and dispersing for 20-40min under the condition that the stirring speed is 1000-2000r/min, then adding diphenylmethane diisocyanate and tricresyl phosphite, continuously stirring and reacting for 2-4h, adding a reinforcing filler after the reaction is completed, and continuously stirring and dispersing for 30-60min to obtain insulating paint;

step two: coating insulating paint on the aluminum core wire, then carrying out paint film curing treatment at the curing temperature of 300-600 ℃, cooling the treated aluminum core wire to room temperature, and taking up wires to obtain the aluminum-based magnetic wire for the micromotor.

As a further scheme of the invention: the insulating paint comprises the following components in parts by weight: 160 parts of trimethylolpropane 140-.

As a further scheme of the invention: the insulating paint is light yellow transparent liquid, and the solid content is 44-46%.

As a further scheme of the invention: the preparation process of the reinforcing filler is as follows:

a1: adding pyromellitic dianhydride, polyethylene glycol and N, N-dimethylformamide into a three-neck flask provided with a stirrer, a condenser tube and a thermometer, heating to 100 ℃ while stirring at the stirring speed of 300-500r/min, then reacting at constant temperature for 3-5h, cooling the reaction product to room temperature after the reaction is finished, distilling the reaction product under reduced pressure to remove the solvent, precipitating and separating the distillation product by using distilled water at the temperature of 60-70 ℃, then placing the precipitate in a vacuum drying box, and drying at the temperature of 60-80 ℃ to constant weight to obtain an intermediate 1;

the reaction principle is as follows:

a2: adding the intermediate 1, pyromellitic dianhydride, N-dimethylformamide, xylene and p-toluenesulfonic acid into a three-neck flask provided with a magnetic stirrer, a condenser pipe, a water separator and a thermometer, stirring and heating to 145 ℃ under the condition of stirring rate of 300 plus one liter of 500r/min, then reacting at constant temperature for 5-7h, cooling the reaction product to room temperature after the reaction is finished, then distilling the reaction product under reduced pressure to remove the solvent, precipitating and separating the distillation product with methanol, then placing the precipitate in a vacuum drying box, and drying to constant weight under the condition of temperature of 60-80 ℃ to obtain an intermediate 2;

the reaction principle is as follows:

a3: adding deionized water and absolute ethyl alcohol into a three-neck flask provided with a magnetic stirrer, a constant-pressure dropping funnel and a thermometer, dropwise adding ammonia water while stirring at the stirring speed of 100-300r/min, controlling the dropwise adding speed to be 0.5-1mL/min, continuously stirring for 3-5min after the dropwise adding is finished, dropwise adding tetraethyl orthosilicate, controlling the dropwise adding speed to be 2-3 s/drop, continuously stirring for reacting for 4-5h after the dropwise adding is finished, washing a reaction product with deionized water after the reaction is finished, centrifuging to take a lower-layer white solution, placing the lower-layer white solution into a vacuum drying box, and drying at the temperature of 80-90 ℃ to constant weight to obtain nano silicon dioxide;

a4: placing nano silicon dioxide in a vacuum drying box at the temperature of 120-125 ℃ for drying for 10-15min, naturally cooling to room temperature, adding the nano silicon dioxide into a three-neck flask provided with a magnetic stirrer, a constant-pressure dropping funnel and a thermometer, then adding toluene a, carrying out ultrasonic dispersion for 40-60min under the condition that the ultrasonic frequency is 45-65kHz, then adding the intermediate 3 dropwise while stirring under the condition that the stirring speed is 100-300r/min, heating to 110-120 ℃ after dropwise addition, carrying out reflux reaction for 8-10h, cooling a reaction product to room temperature after the reaction is finished, carrying out ultrasonic washing for 2-3 times by using toluene b, centrifuging, placing a precipitate in the vacuum drying box, and drying to constant weight under the temperature of 80-90 ℃ to obtain an intermediate 4;

the reaction principle is as follows:

a5: adding the intermediate 4 and acetone into a three-neck flask provided with a mechanical stirrer and a thermometer, stirring and dispersing for 20-30min under the condition of stirring speed of 800-.

The reaction principle is as follows:

as a further scheme of the invention: the using amount ratio of the pyromellitic dianhydride, the polyethylene glycol and the N, N-dimethylformamide in the step A1 is 0.13 mol: 0.20 mol: 100 and 200 mL.

As a further scheme of the invention: the dosage ratio of the intermediate 1, pyromellitic dianhydride, N-dimethylformamide, xylene and p-toluenesulfonic acid in the step A2 is 0.20 mol: 0.12 mol: 100-150 mL: 50-100 mL: 1-10 g.

As a further scheme of the invention: the dosage ratio of the deionized water, the absolute ethyl alcohol, the ammonia water and the tetraethyl orthosilicate in the step A3 is 30 mL: 100mL of: 10mL of: 12mL, wherein the mass fraction of the ammonia water is 25-28%.

As a further scheme of the invention: the intermediate 3 in the step A4 is a solution formed by dissolving KH-550 in deionized water, and the mass ratio of the nano silicon dioxide to the KH-550 is 25: 1, the dosage ratio of the nano silicon dioxide to the toluene a is 1 g: 10 mL.

As a further scheme of the invention: the amount ratio of the intermediate 4, acetone and p-toluenesulfonic acid in step a5 was 1 g: 20mL of: 0.01-0.05g, the molar ratio of the intermediate 4 to the intermediate 2 is 1.0: 0.2-0.5.

As a further scheme of the invention: a preparation method of an aluminum-based magnetic wire for a micromotor comprises the following steps:

the method comprises the following steps: weighing 160 parts of trimethylolpropane 140-one, 900 parts of diphenylmethane diisocyanate 800-one, 1250 parts of butyl acetate 1100-one, 0.390-0.455 part of tricresyl phosphite and 50-100 parts of reinforcing filler for later use;

step two: adding trimethylolpropane into butyl acetate, stirring and dispersing for 20-40min under the condition that the stirring speed is 1000-2000r/min, then adding diphenylmethane diisocyanate and tricresyl phosphite, continuously stirring and reacting for 2-4h, adding a reinforcing filler after the reaction is completed, and continuously stirring and dispersing for 30-60min to obtain insulating paint;

step three: coating insulating paint on the aluminum core wire, then carrying out paint film curing treatment at the curing temperature of 300-600 ℃, cooling the treated aluminum core wire to room temperature, and taking up wires to obtain the aluminum-based magnetic wire for the micromotor.

The invention has the beneficial effects that:

the invention relates to an aluminum-based magnetic wire for a micromotor and a preparation method thereof.A trimethylolpropane is added into butyl acetate to be stirred and dispersed, then diphenylmethane diisocyanate and tricresyl phosphite are added to be continuously stirred and reacted, a reinforcing filler is added to be continuously stirred and dispersed after the reaction is completed to obtain an insulating paint, an aluminum core wire is coated with the insulating paint, then a paint film is solidified, and the treated aluminum core wire is cooled to room temperature and taken up to obtain the aluminum-based magnetic wire for the micromotor;

the preparation method increases the insulating paint component to 34% -36%, thus the solid content is increased from 34% to 36%, the viscosity is only reduced from 700-800mpas to 500-600mpas, the method is suitable for coating thick paint film lines, the low molecular weight has the same or even more reactive sites by increasing the active site density (the content of effective active group-NCO) on the unit molecular chain of the polyurethane resin, thus the method can fully react with other components in the paint to crosslink (such as-OH) to generate amino bonds, because the viscosity of the paint and the molecular weight have direct correspondence, under the condition of the same solid content, the viscosity of the paint is smaller when the molecular weight is smaller, the paint liquid with low paint viscosity can be better leveled on a copper wire in the coating line process, and then the paint liquid is cured to form a film in a furnace chamber, the film can be better formed by faster leveling and curing, the air bubbles brought in during the painting process can disappear more quickly, the defects in the paint film are reduced, the pinhole performance of the paint film is improved, the insulation thickness of the polyurethane wire is improved, the insulation voltage is improved by improving the insulation thickness of the unit sectional area, and the capability of resisting high-pressure pinhole caused by the fact that the paint film is stretched is reduced;

a reinforcing filler is also prepared in the process of preparing the aluminum-based magnetic wire for the micromotor, an intermediate 1 is generated through esterification reaction of pyromellitic dianhydride and polyethylene glycol, then hydroxyl on the intermediate 1 continuously reacts with the pyromellitic dianhydride to generate an intermediate 2, a large amount of carboxyl is arranged on the intermediate 2, by taking tetraethoxysilane as a raw material, preparing nano silicon dioxide by a sol-gel method, hydrolyzing KH-550 to generate silanol, then performing condensation reaction with active hydroxyl on the surface of the nano silicon dioxide to eliminate partial active hydroxyl, reducing the hydrophilic and oleophobic properties of the nano silicon dioxide to generate an intermediate 4, then reacting the intermediate 4 with an intermediate 2, reacting carboxyl on the intermediate 2 with amino and active hydroxyl on the intermediate 4, thereby further reducing the hydrophilic and oleophobic properties of the filler, and simultaneously enabling the filler to carry active groups to obtain the reinforced filler;

the polyurethane resin cured product has high internal crosslinking density and poor toughness, when stress is locally concentrated, cracks can be generated, the defects of the cracks or air bubbles in materials can cause charge accumulation and partial discharge to form an electric branch channel, and particularly, breakdown can be finally generated after the electric branch is further developed under the action of a high electric field for a long time, so that the reliability of high-voltage electric equipment is greatly reduced. The partial discharge and the formation of electric branches caused by cracks are reduced, and further the mechanical and electrical insulation properties of the polyurethane resin are improved, however, the nano silicon dioxide particles are large in surface energy and easy to agglomerate, so that the binding capacity between the silicon dioxide particles and a resin matrix is weakened, and the interface compatibility is reduced, therefore, after the nano silicon dioxide particles are modified by using KH-550 and the intermediate 2, the hydrophilic and oleophobic properties of the nano silicon dioxide particles are reduced, the nano silicon dioxide particles are enhanced in dispersibility and simultaneously carry active groups, the active groups can react with groups generated in the curing reaction process of the polyurethane resin, the active groups and the groups are combined through long molecular chains, the net structure of the nano silicon dioxide particles is more complex, the interface compatibility of the polyurethane resin and the nano silicon dioxide particles is improved, and further the insulation property of the nano silicon dioxide particles is improved.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1:

this example is a reinforcing filler, which is prepared as follows:

a1: adding pyromellitic dianhydride, polyethylene glycol and N, N-dimethylformamide into a three-neck flask provided with a stirrer, a condenser tube and a thermometer, heating to 100 ℃ while stirring at the stirring speed of 300r/min, then carrying out constant-temperature reaction for 3h, cooling a reaction product to room temperature after the reaction is finished, then carrying out reduced-pressure distillation on the reaction product, carrying out precipitation separation on the distillation product by using distilled water at the temperature of 60 ℃, then placing the precipitate in a vacuum drying box, and drying to constant weight at the temperature of 60 ℃ to obtain an intermediate 1; controlling the dosage ratio of pyromellitic dianhydride to polyethylene glycol to N, N-dimethylformamide to be 0.13 mol: 0.20 mol: 100 mL;

a2: adding the intermediate 1, pyromellitic dianhydride, N-dimethylformamide, xylene and p-toluenesulfonic acid into a three-neck flask provided with a magnetic stirrer, a condenser pipe, a water separator and a thermometer, stirring and heating to 145 ℃ under the condition of a stirring speed of 300r/min, then reacting at a constant temperature for 5 hours, cooling a reaction product to room temperature after the reaction is finished, then distilling the reaction product under reduced pressure, precipitating and separating the distillation product with methanol, then placing the precipitate in a vacuum drying oven, and drying at the temperature of 60 ℃ to constant weight to obtain an intermediate 2; controlling the dosage ratio of the intermediate 1, pyromellitic dianhydride, N-dimethylformamide, xylene and p-toluenesulfonic acid to be 0.20 mol: 0.12 mol: 100mL of: 50mL of: 1g of a compound;

a3: adding deionized water and absolute ethyl alcohol into a three-neck flask provided with a magnetic stirrer, a constant-pressure dropping funnel and a thermometer, dropwise adding ammonia water while stirring at a stirring speed of 100r/min, controlling the dropwise adding speed to be 0.5mL/min, continuously stirring for 3min after dropwise adding is finished, dropwise adding tetraethyl orthosilicate, controlling the dropwise adding speed to be 2 s/drop, continuously stirring and reacting for 4h after dropwise adding is finished, washing a reaction product with deionized water after the reaction is finished, centrifuging to take a lower-layer white solution, placing the solution in a vacuum drying oven, and drying to constant weight at a temperature of 80 ℃ to obtain nano silicon dioxide; controlling the dosage ratio of deionized water, absolute ethyl alcohol, ammonia water and tetraethyl orthosilicate to be 30 mL: 100mL of: 10mL of: 12mL, wherein the mass fraction of ammonia water is 25%;

a4: placing nano silicon dioxide in a vacuum drying oven, drying for 10min at 120 ℃, naturally cooling to room temperature, adding the nano silicon dioxide into a three-neck flask provided with a magnetic stirrer, a constant-pressure dropping funnel and a thermometer, then adding toluene a, carrying out ultrasonic dispersion for 40min under the condition that the ultrasonic frequency is 45kHz, then adding an intermediate 3 dropwise while stirring under the condition that the stirring speed is 100r/min, heating to 110 ℃ after dropwise addition, carrying out reflux reaction for 8h, cooling a reaction product to room temperature after the reaction is finished, carrying out ultrasonic washing for 2 times by using toluene b, centrifuging, placing a precipitate in the vacuum drying oven, drying to constant weight under the condition that the temperature is 80 ℃, and obtaining an intermediate 4; controlling the intermediate 3 to be a solution formed by dissolving KH-550 in deionized water, wherein the mass ratio of nano silicon dioxide to KH-550 is 25: 1, the dosage ratio of the nano silicon dioxide to the toluene a is 1 g: 10 mL;

a5: adding the intermediate 4 and acetone into a three-neck flask provided with a mechanical stirrer and a thermometer, stirring and dispersing for 20min under the condition of a stirring speed of 500r/min, then adding the intermediate 2 and p-toluenesulfonic acid, stirring and reacting for 1h under the conditions of a temperature of 100 ℃ and a stirring speed of 1000r/min, placing a reaction product in a vacuum drying oven after the reaction is finished, and drying to constant weight under the condition of a temperature of 80 ℃ to obtain the reinforced filler; controlling the dosage ratio of the intermediate 4, the acetone and the p-toluenesulfonic acid to be 1 g: 20mL of: 0.01g, the molar ratio of the intermediate 4 to the intermediate 2 is 1.0: 0.2.

example 2:

this example is a reinforcing filler, which is prepared as follows:

a1: adding pyromellitic dianhydride, polyethylene glycol and N, N-dimethylformamide into a three-neck flask provided with a stirrer, a condenser tube and a thermometer, heating to 100 ℃ while stirring at a stirring speed of 400r/min, then reacting at a constant temperature for 4 hours, cooling a reaction product to room temperature after the reaction is finished, then distilling the reaction product under reduced pressure, precipitating and separating the distillation product by using distilled water at a temperature of 65 ℃, then placing the precipitate into a vacuum drying box, and drying at a temperature of 70 ℃ to constant weight to obtain an intermediate 1; controlling the dosage ratio of pyromellitic dianhydride to polyethylene glycol to N, N-dimethylformamide to be 0.13 mol: 0.20 mol: 150 mL;

a2: adding the intermediate 1, pyromellitic dianhydride, N-dimethylformamide, xylene and p-toluenesulfonic acid into a three-neck flask provided with a magnetic stirrer, a condenser pipe, a water separator and a thermometer, stirring and heating to 145 ℃ under the condition of a stirring speed of 400r/min, then reacting at a constant temperature for 6 hours, cooling a reaction product to room temperature after the reaction is finished, then distilling the reaction product under reduced pressure, precipitating and separating the distillation product with methanol, then placing the precipitate in a vacuum drying oven, and drying at the temperature of 70 ℃ to constant weight to obtain an intermediate 2; controlling the dosage ratio of the intermediate 1, pyromellitic dianhydride, N-dimethylformamide, xylene and p-toluenesulfonic acid to be 0.20 mol: 0.12 mol: 125 mL: 75mL of: 5g of the total weight of the mixture;

a3: adding deionized water and absolute ethyl alcohol into a three-neck flask provided with a magnetic stirrer, a constant-pressure dropping funnel and a thermometer, dropwise adding ammonia water while stirring at a stirring speed of 200r/min, controlling the dropwise adding speed to be 0.8mL/min, continuously stirring for 4min after dropwise adding is finished, dropwise adding tetraethyl orthosilicate, controlling the dropwise adding speed to be 3 s/drop, continuously stirring and reacting for 5h after dropwise adding is finished, washing a reaction product with deionized water after the reaction is finished, centrifuging to take a lower-layer white solution, placing the solution in a vacuum drying oven, and drying to constant weight at the temperature of 85 ℃ to obtain nano silicon dioxide; controlling the dosage ratio of deionized water, absolute ethyl alcohol, ammonia water and tetraethyl orthosilicate to be 30 mL: 100mL of: 10mL of: 12mL, and the mass fraction of ammonia water is 27%;

a4: placing nano silicon dioxide in a vacuum drying oven, drying for 13min under the condition of 123 ℃, naturally cooling to room temperature, adding the nano silicon dioxide into a three-neck flask provided with a magnetic stirrer, a constant-pressure dropping funnel and a thermometer, then adding toluene a, carrying out ultrasonic dispersion for 50min under the condition of 55kHz ultrasonic frequency, then adding an intermediate 3 dropwise while stirring under the condition of 200r/min stirring speed, heating to 115 ℃ after dropwise addition, carrying out reflux reaction for 9h, cooling a reaction product to room temperature after the reaction is finished, carrying out ultrasonic washing for 3 times by using toluene b, centrifuging, placing a precipitate in the vacuum drying oven, drying to constant weight under the condition of 85 ℃ to obtain an intermediate 4; controlling the intermediate 3 to be a solution formed by dissolving KH-550 in deionized water, wherein the mass ratio of nano silicon dioxide to KH-550 is 25: 1, the dosage ratio of the nano silicon dioxide to the toluene a is 1 g: 10 mL;

a5: adding the intermediate 4 and acetone into a three-neck flask provided with a mechanical stirrer and a thermometer, stirring and dispersing for 25min at a stirring speed of 650r/min, then adding the intermediate 2 and p-toluenesulfonic acid, stirring and reacting for 1.5h at a temperature of 102 ℃ and a stirring speed of 1100r/min, placing a reaction product in a vacuum drying oven after the reaction is finished, and drying to constant weight at a temperature of 85 ℃ to obtain the reinforced filler; controlling the dosage ratio of the intermediate 4, the acetone and the p-toluenesulfonic acid to be 1 g: 20mL of: 0.03g, the molar ratio of intermediate 4 to intermediate 2 is 1.0: 0.3.

example 3:

this example is a reinforcing filler, which is prepared as follows:

a1: adding pyromellitic dianhydride, polyethylene glycol and N, N-dimethylformamide into a three-neck flask provided with a stirrer, a condenser tube and a thermometer, heating to 100 ℃ while stirring at a stirring speed of 500r/min, then carrying out constant-temperature reaction for 5 hours, cooling a reaction product to room temperature after the reaction is finished, then carrying out reduced-pressure distillation on the reaction product, carrying out precipitation separation on the distillation product by using distilled water at a temperature of 70 ℃, then placing the precipitate in a vacuum drying box, and drying to constant weight at a temperature of 80 ℃ to obtain an intermediate 1; controlling the dosage ratio of pyromellitic dianhydride to polyethylene glycol to N, N-dimethylformamide to be 0.13 mol: 0.20 mol: 200 mL;

a2: adding the intermediate 1, pyromellitic dianhydride, N-dimethylformamide, xylene and p-toluenesulfonic acid into a three-neck flask provided with a magnetic stirrer, a condenser pipe, a water separator and a thermometer, stirring and heating to 145 ℃ under the condition of a stirring speed of 500r/min, then carrying out constant-temperature reaction for 7 hours, cooling a reaction product to room temperature after the reaction is finished, then carrying out reduced pressure distillation on the reaction product, carrying out precipitation separation on the distillation product by using methanol, then placing the precipitate in a vacuum drying oven, and drying to constant weight under the condition of a temperature of 80 ℃ to obtain an intermediate 2; controlling the dosage ratio of the intermediate 1, pyromellitic dianhydride, N-dimethylformamide, xylene and p-toluenesulfonic acid to be 0.20 mol: 0.12 mol: 150mL of: 100mL of: 10g of a mixture;

a3: adding deionized water and absolute ethyl alcohol into a three-neck flask provided with a magnetic stirrer, a constant-pressure dropping funnel and a thermometer, dropwise adding ammonia water while stirring at the stirring speed of 300r/min, controlling the dropwise adding speed to be 1mL/min, continuously stirring for 5min after the dropwise adding is finished, dropwise adding tetraethyl orthosilicate, controlling the dropwise adding speed to be 3 s/drop, continuously stirring and reacting for 5h after the dropwise adding is finished, washing a reaction product with deionized water after the reaction is finished, centrifuging to take a lower-layer white solution, placing the lower-layer white solution into a vacuum drying box, and drying to constant weight at the temperature of 90 ℃ to obtain nano silicon dioxide; controlling the dosage ratio of deionized water, absolute ethyl alcohol, ammonia water and tetraethyl orthosilicate to be 30 mL: 100mL of: 10mL of: 12mL, wherein the mass fraction of ammonia water is 28%;

a4: placing nano silicon dioxide in a vacuum drying oven, drying for 15min at 125 ℃, naturally cooling to room temperature, adding the nano silicon dioxide into a three-neck flask provided with a magnetic stirrer, a constant-pressure dropping funnel and a thermometer, then adding toluene a, ultrasonically dispersing for 60min under the condition that the ultrasonic frequency is 65kHz, then adding an intermediate 3 dropwise while stirring under the condition that the stirring speed is 300r/min, heating to 120 ℃ after dropwise adding, carrying out reflux reaction for 10h, cooling a reaction product to room temperature after the reaction is finished, ultrasonically washing the reaction product for 3 times by using toluene b, centrifuging, placing a precipitate in the vacuum drying oven, drying to constant weight under the condition that the temperature is 90 ℃, and obtaining an intermediate 4; controlling the intermediate 3 to be a solution formed by dissolving KH-550 in deionized water, wherein the mass ratio of nano silicon dioxide to KH-550 is 25: 1, the dosage ratio of the nano silicon dioxide to the toluene a is 1 g: 10 mL;

a5: adding the intermediate 4 and acetone into a three-neck flask provided with a mechanical stirrer and a thermometer, stirring and dispersing for 30min under the condition of a stirring speed of 800r/min, then adding the intermediate 2 and p-toluenesulfonic acid, stirring and reacting for 2h under the conditions of a temperature of 105 ℃ and a stirring speed of 1200r/min, placing a reaction product in a vacuum drying oven after the reaction is finished, and drying to constant weight under the condition of a temperature of 90 ℃ to obtain the reinforced filler; controlling the dosage ratio of the intermediate 4, the acetone and the p-toluenesulfonic acid to be 1 g: 20mL of: 0.05g, the molar ratio of intermediate 4 to intermediate 2 is 1.0: 0.5.

example 4:

the embodiment is a preparation method of an aluminum-based magnetic wire for a micromotor, which comprises the following steps:

the method comprises the following steps: weighing 140 parts of trimethylolpropane, 800 parts of diphenylmethane diisocyanate, 1100 parts of butyl acetate, 0.390 part of tricresyl phosphite and 50 parts of reinforcing filler from example 1 according to parts by weight for later use;

step two: adding trimethylolpropane into butyl acetate, stirring and dispersing for 20min under the condition that the stirring speed is 1000r/min, then adding diphenylmethane diisocyanate and tricresyl phosphite, continuously stirring and reacting for 2h, adding a reinforcing filler after the reaction is completed, and continuously stirring and dispersing for 30min to obtain insulating paint;

step three: and coating insulating paint on the aluminum core wire, then carrying out paint film curing treatment at the curing temperature of 300 ℃, cooling the treated aluminum core wire to room temperature, and taking up wires to obtain the aluminum-based magnetic wire for the micromotor.

Example 5:

the embodiment is a preparation method of an aluminum-based magnetic wire for a micromotor, which comprises the following steps:

the method comprises the following steps: weighing 150 parts of trimethylolpropane, 850 parts of diphenylmethane diisocyanate, 1175 parts of butyl acetate, 0.423 part of tricresyl phosphite and 75 parts of reinforcing filler from example 2 according to parts by weight for later use;

step two: adding trimethylolpropane into butyl acetate, stirring and dispersing for 30min under the condition that the stirring speed is 1500r/min, then adding diphenylmethane diisocyanate and tricresyl phosphite, continuously stirring and reacting for 3h, adding a reinforcing filler after the reaction is completed, and continuously stirring and dispersing for 45min to obtain insulating paint;

step three: and coating insulating paint on the aluminum core wire, then carrying out paint film curing treatment at the curing temperature of 450 ℃, cooling the treated aluminum core wire to room temperature, and taking up the wire to obtain the aluminum-based magnetic wire for the micromotor.

Example 6:

the embodiment is a preparation method of an aluminum-based magnetic wire for a micromotor, which comprises the following steps:

the method comprises the following steps: weighing 160 parts of trimethylolpropane, 900 parts of diphenylmethane diisocyanate, 1250 parts of butyl acetate, 0.455 part of tricresyl phosphite and 100 parts of reinforcing filler from example 3 according to the parts by weight for later use;

step two: adding trimethylolpropane into butyl acetate, stirring and dispersing for 40min under the condition that the stirring speed is 2000r/min, then adding diphenylmethane diisocyanate and tricresyl phosphite, continuously stirring and reacting for 4h, adding a reinforcing filler after the reaction is completed, and continuously stirring and dispersing for 60min to obtain insulating paint;

step three: and coating insulating paint on the aluminum core wire, then carrying out paint film curing treatment at the curing temperature of 600 ℃, cooling the treated aluminum core wire to room temperature, and taking up wires to obtain the aluminum-based magnetic wire for the micromotor.

Comparative example 1:

comparative example 1 differs from example 6 in that a polyurethane wire enamel prepared by the method in the paper "research on polyurethane wire enamel paint" of 1993 2 nd proceedings was used instead of the insulating paint.

Comparative example 2:

comparative example 2 differs from example 6 in that no reinforcing filler is added.

Observing the partial discharge initial voltage of the wire enamel in the examples 4-6 and the comparative examples 1-2 by adopting an YDQ15KVA/150KV partial discharge tester, wherein the sample is a sample piece with the thickness of 1mm and the radius of 1.5mm, and a steel round ball with the radius of 1cm is selected as a test electrode; during testing, a sample is clamped between two spherical electrodes and is integrally placed in insulating oil, the surface of the sample is kept clean, the boosting rate is 2kV/s, and the breakdown voltage of the sample is obtained.

Referring to the data, it can be seen that the wire enamel of the present invention has a significantly better insulation effect than the prior art by comparing the examples with the comparative example 1, that the insulation performance can be improved by increasing the solid content of the wire enamel by comparing the comparative example 1 with the comparative example 2, and that the insulation performance can be significantly improved by adding the reinforcing filler to the wire enamel by comparing the examples with the comparative example 2.

In the description herein, references to the description of "one embodiment," "an example," "a specific example" or the like are intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The foregoing is illustrative and explanatory only and is not intended to be exhaustive or to limit the invention to the precise embodiments described, and various modifications, additions, and substitutions may be made by those skilled in the art without departing from the scope of the invention or exceeding the scope of the claims.