Temperature-resistant insulating paper for automobile motor and preparation method thereof

Abstract

This invention provides a method for preparing insulating paper for automotive motors with a temperature resistance of 300℃ or higher, comprising: (1) premixing insulating material and thermally conductive material to obtain an insulating and thermally conductive mixture; the breakdown voltage of the insulating material at a thickness of 1 mm is greater than 100,000 volts; the thermal conductivity of the thermally conductive material is greater than 170 W / mK; (2) punching holes in aramid fiber paper to obtain perforated aramid fiber paper; (3) adding an adhesive to the obtained insulating and thermally conductive mixture and mixing to obtain a coating material; then applying the coating material to one surface of the obtained perforated aramid fiber paper, and then covering the surface of the coating material with another piece of the obtained perforated aramid fiber paper to obtain pre-made insulating paper; (4) hot rolling the obtained pre-made insulating paper to obtain insulating paper for automotive motors. The prepared insulating paper for automotive motors is also provided. This insulating paper for automotive motors has a temperature resistance of 300℃ or higher, a thermal conductivity of 23 W / mK or higher, and a high motor power density.

Description

Technical Field

[0001] This invention belongs to the technical field of insulating paper for automotive motors, specifically relating to insulating paper for automotive motors with a temperature resistance of over 300℃ and its preparation method. Background Technology

[0002] Currently, the highest temperature resistance rating for insulating paper used in domestic automotive motors is below 220℃. Insulating paper is divided into two categories: pure paper and composite paper. Pure paper is generally made of meta-aramid fiber, with foreign products such as DuPont Nomex T410 and Nomex T710, and domestic brands such as Minshida Y510. Composite insulating paper generally comes in brands such as NHN, NMN, and NSN. Based on experience in downgrading insulation materials, the actual maximum operating temperature for 220℃-resistant insulating materials does not exceed 200℃. To further increase the power density of motors, it is necessary to improve the temperature resistance rating and thermal conductivity of the insulating paper, thereby enhancing its heat dissipation capacity.

[0003] Currently, no technical solutions to the aforementioned technical problems have been reported. Summary of the Invention

[0004] The first objective of this invention is to provide a method for preparing insulating paper for automotive motors with a temperature resistance of over 300°C, thereby preparing an insulating paper for automotive motors with a high temperature resistance and thermal conductivity, and thus improving the power density of the motor.

[0005] The second objective of this invention is to provide an insulating paper for automotive motors prepared using the aforementioned method.

[0006] To achieve the first objective of this invention, the following technical solution is adopted:

[0007] A method for preparing insulating paper for automotive motors with a temperature resistance of 300℃ or higher, comprising: Step (1): Premix the insulating material and the thermally conductive material to obtain an insulating and thermally conductive mixture; wherein the breakdown voltage of the insulating material at a thickness of 1 mm is greater than 100,000 volts; and the thermal conductivity of the thermally conductive material is greater than 170 W / mK. Step (2): Punch holes in the aramid fiber paper to obtain perforated aramid fiber paper; Step (3): Add adhesive to the insulating and thermally conductive mixture obtained in step (1) and mix to obtain a coating material; then apply the obtained coating material to one surface of the perforated aramid fiber paper obtained in step (2), and then take another perforated aramid fiber paper obtained in step (2) and cover it on the surface of the coating material to obtain pre-made insulating paper. Step (4) involves rolling the pre-made insulating paper obtained in step (3) with a hot roller to obtain insulating paper for automotive motors.

[0008] The present invention provides a method for preparing insulating paper for automotive motors with a temperature resistance of 300°C or higher. Preferably, in step (1), the proportion of the insulating material in the insulating and thermally conductive mixture is 50-80 wt%.

[0009] The present invention provides a method for preparing insulating paper for automotive motors with a temperature resistance of 300℃ or higher. Preferably, in step (1), the insulating material is sintered mica powder.

[0010] The present invention discloses a method for preparing insulating paper for automotive motors with a temperature resistance of 300℃ or higher. Preferably, the sintered mica powder has the following properties: temperature resistance rating > 700℃, and / or breakdown field strength > 70 KV / mm, and / or thermal conductivity > 0.4 W / mK, and / or density of 2.7 g / cm³. 3 .

[0011] The present invention provides a method for preparing insulating paper for automotive motors with a temperature resistance of 300°C or higher. Preferably, in step (1), the thermally conductive material is aluminum nitride powder.

[0012] The present invention discloses a method for preparing insulating paper for automotive motors with a temperature resistance of 300°C or higher. Preferably, the aluminum nitride powder is a micron-sized powder, and more preferably, its particle size is 40-70 microns.

[0013] The present invention discloses a method for preparing insulating paper for automotive motors with a temperature resistance of 300℃ or higher. Preferably, the aluminum nitride powder has the following properties: temperature resistance rating > 2200℃, and / or breakdown field strength > 15 KV / mm, and / or thermal conductivity > 170 W / mK, and / or density of 3.26 g / cm³. 3 .

[0014] The present invention provides a method for preparing insulating paper for automotive motors with a temperature resistance of 300℃ or higher. Preferably, in step (2), the aramid fiber paper has the following properties: a temperature resistance rating of 500℃ without decomposition, and / or a breakdown field strength > 15 KV / mm, and / or a thermal conductivity > 0.23 W / mK, and / or a density of 1.44 g / cm³. 3 And / or with a thickness of 0.03~0.12 mm.

[0015] The present invention provides a method for preparing insulating paper for automotive motors with a temperature resistance of 300℃ or higher. Preferably, in step (2), there are multiple holes distributed in the middle region of the aramid fiber paper. The distance between the edge of the middle region and the edge of the aramid fiber paper is 2-5 mm. The diameter of the holes is 0.8-1.5 mm. The center-to-center distance between two adjacent holes is 3-4 mm.

[0016] The present invention provides a method for preparing insulating paper for automotive motors with a temperature resistance of 300 ℃ or higher. Preferably, in step (3), the adhesive is epoxy resin. The preferred properties of the epoxy resin include: temperature resistance rating > 200 ℃, and / or breakdown field strength > 25 KV / mm, and / or thermal conductivity > 0.17 W / mK, and / or viscosity < 70 MPa.s.

[0017] The present invention provides a method for preparing insulating paper for automotive motors with a temperature resistance of 300 ℃ or higher. Preferably, in step (3), the amount of coating material applied to the perforated aramid fiber paper is 25~35 g / m², calculated based on the amount of insulating and thermally conductive mixture therein. 2 .

[0018] The present invention provides a method for preparing insulating paper for automotive motors with a temperature resistance of 300 ℃ or higher. Preferably, the hot rolling conditions include: a rolling temperature of 280~310 ℃, and / or a rolling pressure of 1.5~2.5 MPa, and / or a rolling thickness of 0.23~0.32 mm.

[0019] To achieve the second objective of this invention, an insulating paper for automotive motors prepared by the aforementioned method is also provided.

[0020] Preferably, the insulating paper for automotive motors comprises two layers of perforated aramid fiber paper and an insulating and thermally conductive composite layer formed between the two layers of perforated aramid fiber paper; preferably, the thickness of the insulating paper for automotive motors is 0.23~0.32 mm.

[0021] Preferably, the thickness of the insulating paper for the automotive motor is 0.25 mm.

[0022] Preferably, the thickness of the insulating paper for the automotive motor is 0.30 mm.

[0023] The beneficial effects of this invention are as follows: This invention discloses a method for preparing insulating paper for automotive motors with a temperature resistance of over 300°C. The method involves premixing an insulating material with a breakdown voltage greater than 100,000 volts at a thickness of 1 mm with a thermally conductive material with a thermal conductivity greater than 170 W / mK as an insulating and thermally conductive mixture for the intermediate layer, and then punching holes in aramid fiber paper as the surface layer. This process yields an insulating paper for automotive motors with high temperature resistance and thermal conductivity. While meeting voltage strength requirements, its thickness is sufficiently thin, controllable between 0.23 and 0.32 mm, making it suitable for automotive motors and increasing motor power density. Its temperature resistance can reach over 300°C, and its thermal conductivity can reach over 23 W / mK, resulting in high motor power density. Compared to the temperature resistance of ordinary insulating paper (220°C), the temperature resistance of the insulating paper for automotive motors obtained by this invention is significantly improved. Furthermore, compared to the thermal conductivity of ordinary insulating paper (0.17–0.23 W / mK), the thermal conductivity of the insulating paper for automotive motors obtained by this invention is more than 100 times higher. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the three-layer structure of the automotive motor insulating paper with a temperature resistance of over 300°C prepared according to the present invention in one embodiment. Figure 2 yes Figure 1 A schematic diagram of the surface structure of the perforated aramid fiber paper, the outer layer of the insulating paper for automotive motors, in one embodiment. Detailed Implementation

[0025] The technical solution and its effects of the present invention will be further described below with reference to specific embodiments / examples. The following embodiments / examples are only for illustrating the content of the present invention, and the invention is not limited to the following embodiments or examples. Simple modifications made to the present invention based on the concept of the present invention are all within the scope of protection claimed by the present invention.

[0026] This invention provides a method for preparing insulating paper for automotive motors that can withstand temperatures above 300°C, comprising: Step (1): Premix the insulating material and the thermally conductive material to obtain an insulating and thermally conductive mixture; wherein the breakdown voltage of the insulating material at a thickness of 1 mm is greater than 100,000 volts; and the thermal conductivity of the thermally conductive material is greater than 170 W / mK. Step (2): Punch holes in the aramid fiber paper to obtain perforated aramid fiber paper; Step (3): Add adhesive to the insulating and thermally conductive mixture obtained in step (1) and mix to obtain a coating material; then apply the obtained coating material to one surface of the perforated aramid fiber paper obtained in step (2), and then take another perforated aramid fiber paper obtained in step (2) and cover it on the surface of the coating material to obtain pre-made insulating paper. Step (4) involves rolling the pre-made insulating paper obtained in step (3) with a hot roller to obtain insulating paper for automotive motors.

[0027] This invention discloses a method for preparing insulating paper for automotive motors with a temperature resistance of over 300°C. The method involves premixing an insulating material with a breakdown voltage greater than 100,000 volts at a thickness of 1 mm with a thermally conductive material with a thermal conductivity greater than 170 W / mK as an insulating and thermally conductive mixture for the intermediate layer, and then punching holes in aramid fiber paper as the surface layer. This process yields an insulating paper for automotive motors with high temperature resistance and thermal conductivity. While meeting voltage strength requirements, its thickness is sufficiently thin, controllable between 0.23 and 0.32 mm, making it suitable for automotive motors and increasing motor power density. Its temperature resistance can reach over 300°C, and its thermal conductivity can reach over 23 W / mK, resulting in high motor power density. Compared to the temperature resistance of ordinary insulating paper (220°C), the temperature resistance of the insulating paper for automotive motors obtained by this invention is significantly improved. Furthermore, compared to the thermal conductivity of ordinary insulating paper (0.17–0.23 W / mK), the thermal conductivity of the insulating paper for automotive motors obtained by this invention is more than 100 times higher.

[0028] In the automotive motor insulating paper obtained by this invention, the insulating material plays a major insulating role, and the thermally conductive material plays a thermally conductive role. The resulting insulating and thermally conductive mixture is used as the intermediate layer, which not only helps with insulation but also with heat conduction and dissipation, thereby improving the temperature resistance and thermal conductivity of the obtained automotive motor insulating paper. Under the premise of meeting the voltage strength requirements, the thickness is thin enough, which is conducive to its use in automotive motors and to improving the power density of the motor. Furthermore, punching holes in the aramid fiber paper and using it as the surface layer is beneficial for heat dissipation, thereby further improving the temperature resistance and thermal conductivity of the obtained automotive motor insulating paper.

[0029] Those skilled in the art will understand that the pre-made insulating paper obtained in step (3) is a three-layer stacked structure, including a lower layer of perforated aramid fiber paper, a middle layer of coating material, and an upper layer of perforated aramid fiber paper.

[0030] In some specific implementations, in step (1), the proportion of the insulating material in the insulating and thermally conductive mixture is 50~80 wt%, such as 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt%, 75 wt%, and 80 wt%, as well as any value and range within this range.

[0031] Through extensive research, the inventors of this application have discovered that when the proportion of the insulating material in the insulating and thermally conductive mixture is 50-80 wt%, it is beneficial to further improve the temperature resistance and thermal conductivity of the resulting automotive motor insulating paper.

[0032] In some specific implementations, in step (1), the insulating material is sintered mica powder.

[0033] In some specific embodiments, the properties of the sintered mica powder include: a breakdown voltage greater than 100,000 volts at a thickness of 1 mm; a temperature resistance rating > 700 ℃; and / or a breakdown field strength > 70 KV / mm; and / or a thermal conductivity > 0.4 W / mK; and / or a density of 2.7 g / cm³. 3 .

[0034] In some specific implementations, in step (1), the thermally conductive material is aluminum nitride powder.

[0035] In some specific embodiments, the aluminum nitride powder is a micron-sized powder, preferably with a particle size of 40 to 70 microns, such as 40 microns, 45 microns, 50 microns, 55 microns, 60 microns, 65 microns and 70 microns, as well as any value and range within this range.

[0036] In some specific embodiments, the properties of the aluminum nitride powder include: a temperature resistance rating > 2200℃, and / or a breakdown field strength > 15 KV / mm, and / or a thermal conductivity > 170 W / mK, and / or a density of 3.26 g / cm³. 3 .

[0037] In some specific embodiments, in step (2), the properties of the aramid fiber paper include: a temperature resistance rating of 500℃ without decomposition, and / or a breakdown field strength > 15 KV / mm, and / or a thermal conductivity > 0.23 W / mK, and / or a density of 1.44 g / cm³. 3 And / or with a thickness of 0.03~0.12 mm.

[0038] In some specific embodiments, in step (2), there are multiple holes distributed in the middle region of the aramid fiber paper. The distance between the edge of the middle region and the edge of the aramid fiber paper is 2 to 5 mm, such as 2 mm, 3 mm, 4 mm and 5 mm, and any value and range within this range. The diameter of the hole is 0.8 to 1.5 mm, such as 0.8 mm, 0.9 mm, 1.0 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm and 1.5 mm, and any value and range within this range. The center-to-center distance between two adjacent holes is 3 to 4 mm, such as 3 mm, 3.2 mm, 3.4 mm, 3.6 mm, 3.8 mm and 4 mm, and any value and range within this range.

[0039] In this invention, the term "multiple holes" means that there are at least two holes.

[0040] In some specific embodiments, in step (3), the adhesive is epoxy resin; preferably, the properties of the epoxy resin include: temperature resistance rating > 200°C, and / or breakdown field strength > 25 KV / mm, and / or thermal conductivity > 0.17 W / mK, and / or viscosity < 70 MPa.s.

[0041] In some specific embodiments, in step (3), the amount of coating material applied to the perforated aramid fiber paper is 25~35 g / m², based on the amount of insulating and thermally conductive mixture therein. 2 For example, 25 g / m 2 26 g / m 2 27 g / m 2 28 g / m 2 29 g / m 2 30 g / m 2 31 g / m 2 32 g / m 2 33 g / m 2 34 g / m 2 and 35 g / m 2 And any value within that range and the range of values.

[0042] In some specific embodiments, in the automotive motor insulating paper obtained by the present invention, sintered mica powder plays the main insulating role, and aluminum nitride powder plays the thermal conductive role. The two are mixed and used as the intermediate layer, which not only helps with insulation but also helps with heat conduction and heat dissipation, thereby improving the temperature resistance and thermal conductivity of the obtained automotive motor insulating paper. Furthermore, punching holes in aramid fiber paper and using it as the surface layer is beneficial for heat dissipation, thereby further improving the temperature resistance and thermal conductivity of the obtained automotive motor insulating paper.

[0043] In some specific embodiments, the conditions for hot roll rolling include: a rolling temperature of 280~310 ℃, such as 280 ℃, 290 ℃, 300 ℃ and 310 ℃, and any value and range within this range; and / or a rolling pressure of 1.5~2.5 MPa, such as 1.5 MPa, 2 MPa and 2.5 MPa, and any value and range within this range; and / or a rolling thickness of 0.23~0.32 mm, such as 2.5 mm, 3 mm, and any value and range within this range.

[0044] In this invention, hot roll forming is a commonly used process in the field.

[0045] The present invention also provides an insulating paper for automotive motors prepared by the aforementioned method.

[0046] In some specific implementation methods, such as Figures 1-2 As shown, the insulating paper for automotive motors includes two layers of perforated aramid fiber paper 1 and an insulating and thermally conductive composite layer 2 formed between the two layers of perforated aramid fiber paper 1.

[0047] In some specific embodiments, the perforated aramid fiber paper 1 in the automotive motor insulating paper has multiple holes 3 distributed in its central region, and the distance between the edge of the hole and the edge of the central region is 2~5 mm, such as 2 mm, 3 mm, 4 mm and 5 mm, and any value and range within this range; the diameter of the hole 3 is 0.8~1.5 mm, such as 0.8 mm, 0.9 mm, 1.0 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm and 1.5 mm, and any value and range within this range; the center-to-center distance between two adjacent holes 3 is 3~4 mm, such as 3 mm, 3.2 mm, 3.4 mm, 3.6 mm, 3.8 mm and 4 mm, and any value and range within this range.

[0048] In some specific embodiments, the properties of the aramid fiber paper used to make the perforated aramid fiber paper 1 in the automotive motor insulating paper include: a temperature resistance rating of 500℃ without decomposition, and / or a breakdown field strength > 15 KV / mm, and / or a thermal conductivity > 0.23 W / mK, and / or a density of 1.44 g / cm³. 3 And / or with a thickness of 0.03~0.12 mm.

[0049] In this invention, "multiple holes" means that there are at least two holes.

[0050] In some specific embodiments, the insulating paper for automotive motors includes an insulating and thermally conductive mixture layer 2 comprising a mixture of an insulating and thermally conductive mixture and an adhesive; wherein the insulating and thermally conductive mixture comprises a premix of the insulating material and the thermally conductive material; the insulating material has a breakdown voltage greater than 100,000 volts at a thickness of 1 mm; and the thermal conductivity of the thermally conductive material is greater than 170 W / mK.

[0051] In some specific embodiments, the proportion of the insulating material in the insulating and thermally conductive mixture of the automotive motor insulating paper is 50~80 wt%, such as 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt%, 75 wt%, and 80 wt%, as well as any value and range within this range.

[0052] In some specific embodiments, the insulating material is sintered mica powder; preferably, the properties of the sintered mica powder include: temperature resistance rating > 700 ℃, and / or breakdown field strength > 70 KV / mm, and / or thermal conductivity > 0.4 W / mK, and / or density of 2.7 g / cm³. 3 .

[0053] In some specific embodiments, the thermally conductive material is aluminum nitride powder; preferably, the aluminum nitride powder is a micron-sized powder, preferably with a particle size of 40 to 70 microns, such as 40 microns, 45 microns, 50 microns, 55 microns, 60 microns, 65 microns and 70 microns, and any value and range within this range.

[0054] In some specific embodiments, the properties of the aluminum nitride powder include: a temperature resistance rating > 2200℃, and / or a breakdown field strength > 15 KV / mm, and / or a thermal conductivity > 170 W / mK, and / or a density of 3.26 g / cm³. 3 .

[0055] In some specific embodiments, the adhesive in the insulating paper for automotive motors is epoxy resin; preferably, the properties of the epoxy resin include: temperature resistance rating > 200°C, and / or breakdown field strength > 25 KV / mm, and / or thermal conductivity > 0.17 W / mK, and / or viscosity < 70 MPa.s.

[0056] In some specific embodiments, in the insulating paper for automotive motors, the amount of insulating and thermally conductive mixture in the insulating and thermally conductive mixture layer 2 is 25~35 g / m². 2 For example, 25 g / m 2 26 g / m 2 27 g / m 2 28 g / m 2 29 g / m 2 30g / m 2 31 g / m 2 32 g / m 2 33 g / m 2 34 g / m 2 and 35 g / m 2 And any value within that range and the range of values.

[0057] In some specific embodiments, the thickness of the insulating paper for automotive motors is 0.23~0.32 mm, such as 0.25 mm, 0.30 mm, and any value and range within this range.

[0058] In some specific embodiments, the thickness of the insulating paper for the automotive motor is 0.25 mm, and it is used for 800V motors.

[0059] In some specific embodiments, the thickness of the insulating paper for automotive motors is 0.30 mm, and it is used for 1000~1100 V motors.

[0060] The automotive motor insulating paper obtained by the aforementioned preparation method of this invention has a sufficiently thin thickness, controllable between 0.23 and 0.32 mm, while meeting voltage strength requirements, thus enabling its use in automotive motors and improving motor power density. Its temperature resistance can reach over 300 ℃, and its thermal conductivity can reach over 23 W / mk, resulting in high motor power density. Compared to the temperature resistance of ordinary insulating paper (220 ℃), the temperature resistance of the automotive motor insulating paper obtained by this invention is significantly improved. Furthermore, compared to the thermal conductivity of ordinary insulating paper (0.17~0.23 W / mk), the thermal conductivity of the automotive motor insulating paper obtained by this invention is more than 100 times higher.

[0061] The present invention will be further illustrated by the following examples.

[0062] Example 1 The preparation method of the present invention is used to prepare an insulating paper A1 for automotive motors with a temperature resistance of over 300°C, comprising: Step (1) Premix sintered mica powder with aluminum nitride powder to obtain an insulating and thermally conductive mixture; wherein, the breakdown voltage of sintered mica powder at a thickness of 1 mm is greater than 100,000 volts. The sintered mica powder accounts for 70 wt% of the insulating and thermally conductive mixture; The properties of sintered mica powder also include: temperature resistance > 700 ℃, breakdown field strength > 70 KV / mm, thermal conductivity > 0.4 W / mK, and density of 2.7 g / cm³. 3 ; Aluminum nitride powder is a micron-sized powder with a particle size of 40-70 microns; The properties of aluminum nitride powder include: temperature resistance > 2200℃, breakdown field strength > 15 KV / mm, thermal conductivity > 170 W / mK, and density of 3.26 g / cm³. 3 ; Step (2): Perforated aramid fiber paper is obtained by punching holes in the aramid fiber paper; wherein, The properties of aramid fiber paper include: temperature resistance of 500℃ without decomposition, breakdown field strength > 15 KV / mm, thermal conductivity > 0.23 W / mK, and density of 1.44 g / cm³. 3 Thickness is 0.08 mm; There are multiple holes, which are distributed in the middle region of the aramid fiber paper. The distance between the edge of the middle region and the edge of the aramid fiber paper is 2 mm. The diameter of each hole is 1 mm. The center-to-center distance between two adjacent holes is 3 mm. Step (3): Add adhesive to the insulating and thermally conductive mixture obtained in step (1) and mix to obtain a coating material; then apply the obtained coating material to one surface of the perforated aramid fiber paper obtained in step (2), and then take another perforated aramid fiber paper obtained in step (2) and cover it on the surface of the coating material to obtain a three-layer prefabricated insulating paper; wherein, The adhesive is epoxy resin; preferably, the epoxy resin has the following properties: temperature resistance rating > 200℃, breakdown field strength > 25 KV / mm, thermal conductivity > 0.17 W / mK, and viscosity < 70 MPa.s; The amount of coating material applied to the perforated aramid fiber paper, based on the amount of insulating and thermally conductive mixture therein, is 30 g / m². 2 ; Step (4) involves rolling the pre-made insulating paper obtained in step (3) with a hot roller to obtain automotive motor insulating paper A1 with a thickness of 0.30 mm; wherein, The conditions for hot roll rolling include: rolling temperature of 300 ℃, rolling pressure of 2 MPa, and rolling thickness of 0.3 mm.

[0063] Example 2 The insulating paper A2 for automotive motors was prepared using the preparation method of Example 1, with the only difference from Example 1 being: In step (1), the sintered mica powder accounts for 50 wt% of the insulating and thermally conductive mixture; In step (2), the aramid fiber paper has multiple holes distributed in the middle area of ​​the aramid fiber paper. The distance between the edge of the middle area and the edge of the aramid fiber paper is 5 mm. The diameter of the hole is 1.5 mm. The center-to-center distance between two adjacent holes is 4 mm. In step (3), the amount of coating material applied to the perforated aramid fiber paper is 25 g / m², calculated based on the amount of insulating and thermally conductive mixture therein. 2 ; In step (4), the conditions for hot roll rolling include: rolling temperature of 280 ℃, rolling pressure of 1.5 MPa, and rolling thickness of 0.3 mm.

[0064] Example 3 The insulating paper A3 for automotive motors was prepared using the preparation method of Example 1, with the only difference from Example 1 being: In step (1), the sintered mica powder accounts for 50 wt% of the insulating and thermally conductive mixture; In step (2), the aramid fiber paper has multiple holes distributed in the middle area of ​​the aramid fiber paper. The distance between the edge of the middle area and the edge of the aramid fiber paper is 5 mm. The diameter of the hole is 1.5 mm. The center-to-center distance between two adjacent holes is 4 mm. In step (3), the amount of coating material applied to the perforated aramid fiber paper is 25 g / m², calculated based on the amount of insulating and thermally conductive mixture therein. 2 .

[0065] Example 4 The insulating paper A4 for automotive motors was prepared using the preparation method of Example 1, with the only difference from Example 1 being: In step (1), the proportion of sintered mica powder in the insulating and thermally conductive mixture is 50 wt%.

[0066] Example 5 The insulating paper A5 for automotive motors was prepared using the preparation method of Example 1, with the only difference from Example 1 being: In step (3), the amount of coating material applied to the perforated aramid fiber paper is 25 g / m², calculated based on the amount of insulating and thermally conductive mixture therein. 2 .

[0067] Example 6 The insulating paper A6 for automotive motors was prepared using the preparation method of Example 1, with the only difference from Example 1 being: In step (1), the sintered mica powder accounts for 80 wt% of the insulating and thermally conductive mixture; In step (2), the aramid fiber paper has multiple holes distributed in the middle region of the aramid fiber paper. The distance between the edge of the middle region and the edge of the aramid fiber paper is 4 mm. The diameter of the hole is 0.8 mm. The center-to-center distance between two adjacent holes is 3.5 mm. In step (3), the amount of coating material applied to the perforated aramid fiber paper is 35 g / m², calculated based on the amount of insulating and thermally conductive mixture therein. 2 ; In step (4), the conditions for hot roll rolling include: rolling temperature of 310 ℃, rolling pressure of 2.5 MPa, and rolling thickness of 0.3 mm.

[0068] Example 7 The insulating paper A7 for automotive motors was prepared using the preparation method of Example 1, with the only difference from Example 1 being: In step (1), the sintered mica powder accounts for 80 wt% of the insulating and thermally conductive mixture; In step (2), the aramid fiber paper has multiple holes distributed in the middle region of the aramid fiber paper. The distance between the edge of the middle region and the edge of the aramid fiber paper is 4 mm. The diameter of the hole is 0.8 mm. The center-to-center distance between two adjacent holes is 3.5 mm. In step (3), the amount of coating material applied to the perforated aramid fiber paper is 35 g / m², calculated based on the amount of insulating and thermally conductive mixture therein. 2 .

[0069] Example 8 The insulating paper A8 for automotive motors was prepared using the preparation method of Example 1, with the only difference from Example 1 being: In step (1), the proportion of sintered mica powder in the insulating and thermally conductive mixture is 80 wt%.

[0070] Example 9 The insulating paper A9 for automotive motors was prepared using the preparation method of Example 1, with the only difference from Example 1 being: In step (3), the amount of coating material applied to the perforated aramid fiber paper is 35 g / m², calculated based on the amount of insulating and thermally conductive mixture therein. 2 .

[0071] Example 10 Insulating paper A10 for automotive motors was prepared using the preparation method of Example 1, with the only difference from Example 1 being: In step (4), the rolling thickness is 0.25 mm.

[0072] Example 11 The insulating paper A11 for automotive motors was prepared using the preparation method of Example 1, and its only difference from that of Example 2 is: In step (4), the rolling thickness is 0.25 mm.

[0073] Example 12 The insulating paper A12 for automotive motors was prepared using the preparation method of Example 1, and its only difference from Example 3 is: In step (4), the rolling thickness is 0.25 mm.

[0074] Example 13 The insulating paper A13 for automotive motors was prepared using the preparation method of Example 1, and its only difference from Example 4 is: In step (4), the rolling thickness is 0.25 mm.

[0075] Example 14 The insulating paper A14 for automotive motors was prepared using the preparation method of Example 1, and its only difference from Example 5 is: In step (4), the rolling thickness is 0.25 mm.

[0076] Example 15 The insulating paper A15 for automotive motors was prepared using the preparation method of Example 1, and its only difference from Example 6 is: In step (4), the rolling thickness is 0.25 mm.

[0077] Example 16 The insulating paper A16 for automotive motors was prepared using the preparation method of Example 1, and its only difference from that of Example 7 is: In step (4), the rolling thickness is 0.25 mm.

[0078] Example 17 The insulating paper A17 for automotive motors was prepared using the preparation method of Example 1, and its only difference from Example 8 is: In step (4), the rolling thickness is 0.25 mm.

[0079] Example 18 The insulating paper A18 for automotive motors was prepared using the preparation method of Example 1, and its only difference from that of Example 9 is: In step (4), the rolling thickness is 0.25 mm.

[0080] The insulating paper A1-18 for automotive motors obtained in Examples 1-18 was subjected to relevant performance tests. The specific test items and test standards are as follows.

[0081] 1) Standard thickness, standard weight, transverse tensile strength, longitudinal tensile strength, transverse elongation at break, longitudinal elongation at break, hot bonding, and appearance: The aforementioned items of insulating paper for automotive motors are tested according to the test standard GB / T5591.2-2017.

[0082] 2) Breakdown voltage: According to the test standard GB / T1408.1-2011, the breakdown voltage of the insulating paper for automotive motors is tested, and the voltage rise rate is 1000 V / second.

[0083] 3) PDIV partial discharge initiation voltage: According to the test standard GB / T7354-2018, PDIV>1300 V, test the PDIV partial discharge initiation voltage of the insulating paper for automotive motors.

[0084] 4) Temperature resistance rating: The temperature resistance rating of insulating paper for automotive motors is evaluated according to the test standard GB / T11026-2018.

[0085] 5) Thermal conductivity of insulation layer: The thermal conductivity of insulating paper for automotive motors was tested according to the hot wire method in GB / T10297-2015.

[0086] Test results show that the automotive motor insulating paper A1-18 obtained in Examples 1-18 has a transverse tensile strength of 63-70 MPa, a longitudinal tensile strength of 78-85 MPa, a transverse elongation at break of 5.5%, a longitudinal elongation at break of 5.5%, and exhibits no bubbling or glue flow during hot bonding at 300℃ for 4 hours; its appearance is grayish-brown. The automotive motor insulating paper A1-9 obtained in Examples 1-9 (all with a thickness of 0.3 mm) has a breakdown voltage of 11300-11500 V, a DIV partial discharge initiation voltage of 1300-1400 V, a temperature rating of 310-320 ℃, and a thermal conductivity of 24-30 W / mK, making it suitable for use in 1000-1100 V motors. The automotive motor insulating paper A10-18 obtained in Examples 10-18 (all with a thickness of 0.25 mm) has a breakdown voltage of 8500-9000 V and a DIV partial discharge initiation voltage of 1100-1200 V. V, with a temperature rating of 310~320 ℃ and a thermal conductivity of 24~30 W / mk, it can be used in 800V motors.

[0087] The relevant test results of the automotive motor insulating paper A1 obtained in Example 1 are shown in Table 1.

[0088] Table 1. Performance test results of automotive motor insulating paper A1 obtained in Example 1

[0089] Application Example 1 The automotive motor insulating papers A1-9 (all with a thickness of 0.3 mm) obtained in Examples 1-9 were applied to 1000-1100 V motors. It was found that they could operate continuously and stably at 300°C; and compared with the application of ordinary insulating paper, the motor power density was increased by 44-50%.

[0090] Application Example 2 The automotive motor insulating paper A10-18 (all with a thickness of 0.25 mm) obtained in Examples 10-18 was applied to an 800V motor. It was found that it could operate continuously and stably at 300°C; and compared with the application of ordinary insulating paper, the motor power density was increased by 44-50%.

[0091] This invention discloses a method for preparing insulating paper for automotive motors with a temperature resistance of over 300°C. The method involves premixing an insulating material with a breakdown voltage greater than 100,000 volts at a thickness of 1 mm with a thermally conductive material with a thermal conductivity greater than 170 W / mK as an insulating and thermally conductive mixture for the intermediate layer, and then punching holes in aramid fiber paper as the surface layer. This process yields an insulating paper for automotive motors with high temperature resistance and thermal conductivity. While meeting voltage strength requirements, its thickness is sufficiently thin, controllable between 0.23 and 0.32 mm, making it suitable for automotive motors and increasing motor power density. Its temperature resistance can reach over 300°C, and its thermal conductivity can reach over 23 W / mK, resulting in high motor power density. Compared to the temperature resistance of ordinary insulating paper (220°C), the temperature resistance of the insulating paper for automotive motors obtained by this invention is significantly improved. Furthermore, compared to the thermal conductivity of ordinary insulating paper (0.17–0.23 W / mK), the thermal conductivity of the insulating paper for automotive motors obtained by this invention is more than 100 times higher.

[0092] The above embodiments / examples are only used to illustrate the content of the present invention and are not limited thereto. Any simple changes made to the present invention based on the concept of the present invention are within the scope of protection claimed by the present invention.

Claims

1. A method for preparing insulating paper for automotive motors with a temperature resistance of 300℃ or higher, characterized in that, The preparation method includes: Step (1): Premix the insulating material and the thermally conductive material to obtain an insulating and thermally conductive mixture; wherein the breakdown voltage of the insulating material at a thickness of 1 mm is greater than 100,000 volts; and the thermal conductivity of the thermally conductive material is greater than 170 W / mK. Step (2): Punch holes in the aramid fiber paper to obtain perforated aramid fiber paper; Step (3): Add adhesive to the insulating and thermally conductive mixture obtained in step (1) and mix to obtain a coating material; then apply the obtained coating material to one surface of the perforated aramid fiber paper obtained in step (2), and then take another perforated aramid fiber paper obtained in step (2) and cover it on the surface of the coating material to obtain pre-made insulating paper. Step (4): The pre-made insulating paper obtained in step (3) is rolled by hot roller to obtain insulating paper for automotive motors.

2. The preparation method according to claim 1, characterized in that, In step (1), the insulating material accounts for 50-80 wt% of the insulating and thermally conductive mixture.

3. The preparation method according to claim 1 or 2, characterized in that, In step (1), the insulating material is sintered mica powder; Preferably, the sintered mica powder has the following properties: temperature resistance > 700 ℃, and / or breakdown field strength > 70 KV / mm, and / or thermal conductivity > 0.4 W / mK, and / or density of 2.7 g / cm³. 3 .

4. The preparation method according to any one of claims 1-3, characterized in that, In step (1), the thermally conductive material is aluminum nitride powder; Preferably, the aluminum nitride powder is a micron-sized powder, with a preferred particle size of 40-70 micrometers; and / or, The properties of the aluminum nitride powder include: temperature resistance rating > 2200℃, and / or breakdown field strength > 15 KV / mm, and / or thermal conductivity > 170 W / mK, and / or density of 3.26 g / cm³. 3 .

5. The preparation method according to any one of claims 1-4, characterized in that, In step (2), the properties of the aramid fiber paper include: a temperature resistance rating of 500℃ without decomposition, and / or a breakdown field strength > 15KV / mm, and / or a thermal conductivity > 0.23 W / mK, and / or a density of 1.44 g / cm³. 3 And / or with a thickness of 0.03~0.12mm; and / or, In step (2), there are multiple holes distributed in the middle area of ​​the aramid fiber paper. The distance between the edge of the middle area and the edge of the aramid fiber paper is 2-5 mm. The diameter of the hole is 0.8-1.5 mm. The center-to-center distance between two adjacent holes is 3-4 mm.

6. The preparation method according to any one of claims 1-5, characterized in that, In step (3), the adhesive is epoxy resin; preferably, the epoxy resin has the following properties: temperature resistance rating > 200℃, and / or breakdown field strength > 25 KV / mm, and / or thermal conductivity > 0.17 W / mK, and / or viscosity < 70 MPa.s; and / or, In step (3), the amount of coating material applied to the perforated aramid fiber paper is 25~35 g / m², based on the amount of insulating and thermally conductive mixture therein. 2 .

7. The preparation method according to any one of claims 1-6, characterized in that, In step (4), the conditions for hot roll rolling include: rolling temperature of 280~310 ℃, and / or rolling pressure of 1.5~2.5MPa, and / or rolling thickness of 0.23~0.32 mm.

8. An insulating paper for automotive motors prepared by the method according to any one of claims 1-7, characterized in that, The insulating paper for automotive motors comprises two layers of perforated aramid fiber paper (1) and an insulating and thermally conductive composite layer (2) formed between the two layers of perforated aramid fiber paper (1); preferably, the thickness of the insulating paper for automotive motors is 0.23~0.32 mm.

9. The insulating paper for automotive motors according to claim 8, characterized in that, The thickness of the insulating paper for the automotive motor is 0.25 mm.

10. The insulating paper for automotive motors according to claim 8, characterized in that, The thickness of the insulating paper for the automotive motor is 0.30 mm.

Images