High-temperature-resistant insulating paint as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of wires and cables, and particularly relates to high-temperature-resistant insulating paint as well as a preparation method and application thereof. The high-temperature-resistant insulating paint comprises the following raw materials: a paint material and a curing material, the paint vehicle is prepared from the following components in parts by weight: 180 parts of organic silicon resin, 20 to 25 parts of hydrophobic fumed silica, 20 to 30 parts of modified aluminum oxide, 15 to 30 parts of modified zinc oxide and 0 to 5 parts of auxiliaries; the curing material comprises the following raw material components in parts by weight: 20-35 parts of an amide curing agent. According to the high-temperature-resistant insulating paint provided by the invention, under the synergistic effect of the organic silicon resin, the hydrophobic fumed silica, the modified aluminum oxide and the modified zinc oxide, the high-temperature-resistant insulating paint has very high wear resistance, high temperature resistance, insulativity and thermal conductivity.

Description

Technical Field

[0001] The present application belongs to the technical field of electric wires and cables, and specifically relates to a high temperature resistant insulating varnish and a preparation method and application thereof. Background Art

[0002] Thermocouples are commonly used temperature measuring elements in temperature measuring instruments. Their working principle is based on the thermoelectric effect, that is, when two different conductors or semiconductors A and B form a loop and are connected at both ends, as long as the temperatures at the two nodes are different, an electromotive force will be generated in the loop. By measuring the change in electromotive force, the corresponding measured temperature can be obtained. Thermocouple wires are an important component of thermocouples and are used to transmit signals.

[0003] In high temperature and interference environments, the insulating paint on the thermocouple wire is prone to brittleness and aging, resulting in open circuit or short circuit of the line, affecting the accuracy of the measurement results. To solve this problem, inorganic resin materials are widely used in components such as thermocouple wires. This material has excellent high temperature and chemical resistance as well as excellent electrical and insulation properties, which can cope with the challenges brought by high temperature and interference, and ensure accurate measurement of thermocouples.

[0004] However, existing inorganic resin materials cannot meet the use requirements of components such as thermocouples in high temperature environments. Their short service life affects the accuracy of thermocouple measurements and in severe cases may endanger life and property safety. Summary of the invention

[0005] In order to solve the above problems, the present application proposes a high temperature resistant insulating paint and a preparation method and application thereof, so as to solve at least one aspect of the problems and defects raised in the above background technology.

[0006] This application is implemented through the following technical solutions:

[0007] The first aspect of the present application provides a high temperature resistant insulating paint, wherein the raw materials of the high temperature resistant insulating paint include a paint and a curing material; the paint includes the following components in parts by weight:

[0008] 180 parts of organic silicone resin, 20 to 25 parts of hydrophobic fumed silica, 20 to 30 parts of modified aluminum oxide, 15 to 30 parts of modified zinc oxide and 0 to 5 parts of auxiliary agent;

[0009] The curing material comprises the following raw material components in parts by weight: 20 to 35 parts of amide curing agent.

[0010] The high temperature resistant insulating paint provided by the present application has an organic silicon resin as the main material in the paint; hydrophobic fumed silica improves the rheological properties of the high temperature resistant insulating paint, improves the wear resistance of the high temperature resistant insulating paint and enhances the strength of the high temperature resistant insulating paint; modified aluminum oxide and modified zinc oxide can be evenly dispersed in the organic silicon resin to improve the high temperature resistance and thermal conductivity of the high temperature resistant insulating paint. The high temperature resistant insulating paint provided by the present application has high wear resistance, high temperature resistance, insulation and thermal conductivity under the synergistic effect of organic silicon resin, hydrophobic fumed silica, modified aluminum oxide and modified zinc oxide.

[0011] In some possible implementations, the purity of the hydrophobic fumed silica is greater than 99.8%.

[0012] In some possible implementations, the specific surface area of ​​the hydrophobic fumed silica is 200 m 2 / g~300m 2 In this case, the hydrophobic fumed silica has good dispersibility and stability in the silicone resin, and is uniformly dispersed in the silicone resin to improve the rheological properties, wear resistance and strength of the high temperature resistant insulating varnish.

[0013] In some possible implementations, the preparation of the modified aluminum oxide includes the following steps: mixing aluminum oxide powder and aminosilane coupling agent and drying to obtain the modified aluminum oxide. In some possible implementations, the preparation of the modified zinc oxide includes the following steps: mixing zinc oxide powder and para-hydroxymethylbenzoic acid and drying to obtain the modified zinc oxide. In this case, the lipophilicity of aluminum oxide and zinc oxide is greatly improved after modification, and they can be evenly dispersed in the silicone resin without relying on additives and will not agglomerate; the amino group in the modified aluminum oxide is hydrogen-bonded with the carboxyl group in the modified zinc oxide, so that the modified aluminum oxide and the modified zinc oxide are cross-linked into a thermally conductive network structure, which greatly improves the thermal conductivity of the high temperature resistant insulating paint.

[0014] In some possible implementations, the aminosilane coupling agent includes at least one of KH-550 (γ-aminopropyltriethoxysilane), KH-540 (γ-aminopropyltrimethoxysilane), KH-792 (N-(2-aminoethyl)-3-aminopropyltrimethoxysilane), and A-1100 (3-aminopropyltriethoxysilane).

[0015] In some possible implementations, the mass ratio of the aluminum oxide powder to the aminosilane coupling agent is (2-5): 1. In this case, the aminosilane coupling agent fully modifies the aluminum oxide powder to obtain the modified aluminum oxide.

[0016] In some possible implementations, in the preparation of the modified alumina, the drying method includes spray drying or oven drying, and the drying temperature is 110° C. to 150° C. until the weight loss rate is less than 1%.

[0017] In some possible implementations, the mass ratio of the zinc oxide fine powder to the p-hydroxymethylbenzoic acid is (1-5): 1. In this case, the p-hydroxymethylbenzoic acid fully modifies the zinc oxide fine powder to obtain the modified zinc oxide.

[0018] In some possible implementations, in the preparation of the modified zinc oxide, the drying method includes spray drying or oven drying, and the drying temperature is 160° C. to 200° C. until the weight loss rate is less than 1%.

[0019] In some possible implementations, the average particle size of the modified aluminum oxide is 5 μm to 25 μm. In some possible implementations, the average particle size of the modified zinc oxide is 40 μm to 85 μm. In this case, the modified aluminum oxide is evenly dispersed and fills the gaps in the modified zinc oxide and cross-links with the modified zinc oxide to form a thermally conductive network structure, thereby improving the uniformity and high temperature resistance of the high temperature resistant insulating paint.

[0020] In some possible implementations, the auxiliary agent includes at least one of a dispersant and a leveling agent. In this case, the auxiliary agent can promote mixing between the inorganic phase (mainly fumed silica) and the organic phase, and improve the mixing uniformity of the paint.

[0021] In some possible implementations, the dispersant is Texaphor963.

[0022] In some possible implementations, the leveling agent is T-306.

[0023] In some possible implementations, the preparation step of the paint comprises: adding an auxiliary agent to the silicone resin under stirring, then adding hydrophobic fumed silica, and finally adding modified aluminum oxide and modified zinc oxide to obtain a paint. In this case, an auxiliary agent (if any) is first added to the silicone resin, and then hydrophobic fumed silica is added so that the hydrophobic fumed silica can be evenly dispersed in the silicone resin, and finally the modified aluminum oxide and the modified zinc oxide are added. This preparation step can make the components evenly mixed to form a uniform and difficult to settle paint.

[0024] Furthermore, in the preparation of the above-mentioned paint, the stirring method is mechanical stirring or magnetic stirring.

[0025] Furthermore, in the preparation of the above-mentioned paint, the stirring speed is 850r / min to 1000r / min. In this case, when the auxiliary agent and the hydrophobic fumed silica are added, the stirring speed is 900r / min to 1000r / min. A higher stirring speed can promote the mixing between the organic silicone resin of the organic phase and the hydrophobic fumed silica of the inorganic phase; when the modified aluminum oxide and the modified zinc oxide are added, the stirring speed is 850r / min to 900r / min. A lower stirring speed can promote the formation of a cross-linked network structure between the modified aluminum oxide and the modified zinc oxide.

[0026] In some possible implementations, the amide curing agent is polyamide 650.

[0027] A second aspect of the present application provides a method for preparing a high temperature resistant insulating varnish, comprising the following steps:

[0028] The paint and curing material are mixed and then cured to obtain the high temperature resistant insulating paint.

[0029] In some possible implementations, the step of mixing the paint and the curing material includes: mixing the paint and the curing material under stirring conditions.

[0030] In some possible implementations, the stirring method is mechanical stirring or magnetic stirring.

[0031] In some possible implementations, the stirring speed is 400 r / min to 580 r / min. In this case, stirring at a lower stirring speed can promote uniform mixing of the paint and the curing material without destroying the network structure already formed by the modified aluminum oxide and the modified zinc oxide.

[0032] In some possible implementations, the time for mixing the paint and the curing material is 0.8 hours to 1.2 hours. In this case, a longer mixing time can make the paint and the curing material fully mixed and uniform.

[0033] In some possible implementations, the paint and the curing material are mixed in a manner including: dripping the curing material into the paint at a temperature of 10° C. to 20° C. at a dripping rate of 60 d / min to 80 d / min. In this case, the paint and the curing material are mixed evenly and are not or rarely cured.

[0034] In some possible implementations, the curing temperature is 65°C to 85°C.

[0035] In some possible implementations, the curing time is 25 min to 50 min.

[0036] The third aspect of the present application provides an application of high temperature resistant insulating varnish in the field of wires and cables. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is described and illustrated below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application. Based on the embodiments provided in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present application.

[0038] Obviously, the following descriptions are only some examples or embodiments of the present application. For ordinary technicians in this field, the present application can also be applied to other similar scenarios without creative work. In addition, it can also be understood that although the efforts made in this development process may be complicated and lengthy, for ordinary technicians in the field related to the content disclosed in this application, some changes in design, manufacturing or production based on the technical content disclosed in this application are just conventional technical means, and should not be understood as insufficient content disclosed in this application.

[0039] However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repeated descriptions of substantially the same structures may be omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate understanding by those skilled in the art. In addition, the following description is provided for those skilled in the art to fully understand the present application and is not intended to limit the subject matter described in the claims.

[0040] If not otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution, and all technical features and optional technical features of the present application can be combined with each other to form a new technical solution.

[0041] Example 1

[0042] Embodiment 1 provides a high temperature resistant insulating paint, the raw materials of which are divided into paint and curing material; the paint is composed of the following components in parts by weight:

[0043] 180 parts of organic silicon resin, 20 parts of hydrophobic fumed silica, 25 parts of modified aluminum oxide and 20 parts of modified zinc oxide; wherein the specific surface area of ​​the hydrophobic fumed silica is 210 m 2 / g, the average particle size of modified aluminum oxide is 18 μm, and the average particle size of modified zinc oxide is 50 μm.

[0044] The curing material is polyamide 650, with a weight portion of 20 parts.

[0045] This embodiment also provides a method for preparing the high temperature resistant insulating paint provided in this embodiment, and the steps are as follows:

[0046] (1) Preparation of modified alumina: Alumina powder and KH-550 were mixed in a mass ratio of 3:1 and dried at 130° C. until the weight loss rate was less than 1%, thereby obtaining modified alumina.

[0047] (2) Preparation of modified zinc oxide: Zinc oxide powder and p-hydroxymethylbenzoic acid are mixed in a mass ratio of 2:1 and dried at 180° C. until the weight loss rate is less than 1%, thereby obtaining modified zinc oxide, wherein the relative molecular weight of p-hydroxymethylbenzoic acid is 2000.

[0048] (3) Preparing a paint: adding hydrophobic fumed silica to an organic silicone resin at a rotation speed of 980 r / min; then adding modified aluminum oxide and modified zinc oxide in sequence at a rotation speed of 850 r / min, stirring evenly, and obtaining a paint.

[0049] (4) Preparation of insulating varnish: At a rotation speed of 500 r / min and a temperature of 10°C, polyamide 650 was dripped into the varnish at a dripping rate of 70 d / min. After the dripping was completed, it was cured at 70°C for 40 min to obtain a high temperature resistant insulating varnish.

[0050] Example 2

[0051] Example 2 proposes a high temperature resistant insulating paint, the raw material components of which are basically the same as those of Example 1, except that the paint component also contains 1 part by weight of Texaphor 963 (dispersant):

[0052] Example 2 also provides a method for preparing the high temperature resistant insulating paint provided in this example, and the steps are basically the same as those in Example 1, except that: in step (3), at a rotation speed of 980 r / min, Texaphor 963 is first added, and then the hydrophobic gas-phase silica is added to the silicone resin.

[0053] Example 3

[0054] Example 3 proposes a high temperature resistant insulating paint, the raw material components of which are basically the same as those of Example 1, except that the paint also contains 1 part by weight of Texaphor 963 (dispersant) and 1 part of T-306 (leveling agent):

[0055] Example 3 also provides a method for preparing the high temperature resistant insulating paint provided in this example. The steps are basically the same as those in Example 1, except that: in step (3), at a rotation speed of 980 r / min, Texaphor 963 and T-306 are first added, and then the hydrophobic gas-phase silica is added to the silicone resin.

[0056] Example 4

[0057] Embodiment 4 provides a high temperature resistant insulating paint, the raw materials of which are divided into paint and curing material; the paint is composed of the following components in parts by weight:

[0058] 180 parts of organic silicone resin, 25 parts of hydrophobic fumed silica, 20 parts of modified alumina, 30 parts of modified zinc oxide, 2 parts of Texaphor 963 (dispersant) and 1 part of T-306 (leveling agent); wherein the specific surface area of ​​the hydrophobic fumed silica is 210 m 2 / g, the average particle size of modified aluminum oxide is 18 μm, and the average particle size of modified zinc oxide is 50 μm.

[0059] The curing material is polyamide 650, with a weight portion of 20 parts.

[0060] Example 4 also provides a method for preparing the high temperature resistant insulating varnish provided in this example, and the steps are the same as those in Example 3.

[0061] Example 5

[0062] Embodiment 5 provides a high temperature resistant insulating paint, the raw materials of which are divided into paint and curing material; the paint is composed of the following components in parts by weight:

[0063] 180 parts of organic silicone resin, 25 parts of hydrophobic fumed silica, 30 parts of modified alumina, 15 parts of modified zinc oxide, 2 parts of Texaphor 963 (dispersant) and 2 parts of T-306 (leveling agent); wherein the specific surface area of ​​the hydrophobic fumed silica is 210 m 2 / g, the average particle size of modified aluminum oxide is 18 μm, and the average particle size of modified zinc oxide is 50 μm.

[0064] The curing material is polyamide 650, with a weight portion of 20 parts.

[0065] Example 5 also provides a method for preparing the high temperature resistant insulating paint provided in this example, and the steps are the same as those in Example 3.

[0066] Example 6

[0067] Embodiment 6 provides a high temperature resistant insulating paint, the raw materials of which are divided into paint and curing material; the paint is composed of the following components in parts by weight:

[0068] 180 parts of organic silicone resin, 20 parts of hydrophobic fumed silica, 20 parts of modified alumina, 15 parts of modified zinc oxide, 1 part of Texaphor 963 (dispersant) and 2 parts of T-306 (leveling agent); wherein the specific surface area of ​​the hydrophobic fumed silica is 210 m 2 / g, the average particle size of modified aluminum oxide is 18 μm, and the average particle size of modified zinc oxide is 50 μm.

[0069] The curing material is polyamide 650, with a weight portion of 20 parts.

[0070] Example 6 also provides a method for preparing the high temperature resistant insulating paint provided in this example, and the steps are the same as those in Example 3.

[0071] Comparative Example 1

[0072] Comparative Example 1 proposes an insulating paint, the raw materials of which are divided into a paint and a curing material; the paint is composed of the following components in parts by weight:

[0073] 180 parts of organic silicon resin, 35 parts of modified aluminum oxide and 30 parts of modified zinc oxide; wherein the average particle size of the modified aluminum oxide is 18 μm, and the average particle size of the modified zinc oxide is 50 μm.

[0074] The curing material is polyamide 650, with a weight portion of 20 parts.

[0075] Comparative Example 2

[0076] Comparative Example 2 proposes an insulating paint, the raw materials of which are divided into a paint and a curing material; the paint is composed of the following components in parts by weight:

[0077] 180 parts of organic silicon resin, 35 parts of hydrophobic fumed silica and 30 parts of modified zinc oxide; wherein the specific surface area of ​​the hydrophobic fumed silica is 210 m 2 / g, and the average particle size of modified zinc oxide is 50μm.

[0078] The curing material is polyamide 650, with a weight portion of 20 parts.

[0079] Comparative Example 3

[0080] Comparative Example 3 proposes an insulating paint, the raw materials of which are divided into a paint and a curing material; the paint is composed of the following components in parts by weight:

[0081] 180 parts of organic silicon resin, 30 parts of hydrophobic fumed silica and 35 parts of modified alumina; wherein the specific surface area of ​​the hydrophobic fumed silica is 210 m 2 / g, and the average particle size of modified alumina is 18μm.

[0082] The curing material is polyamide 650, with a weight portion of 20 parts.

[0083] Comparative Example 4

[0084] Comparative Example 4 proposes an insulating paint, the raw materials of which are divided into a paint and a curing material; the paint is composed of the following components in parts by weight:

[0085] 180 parts of organic silicone resin, 30 parts of hydrophobic fumed silica, 25 parts of aluminum oxide powder, 20 parts of zinc oxide powder, 2 parts of Texaphor 963 (dispersant) and 1 part of T-306 (leveling agent); the specific surface area of ​​the hydrophobic fumed silica is 210 m 2 / g, the average particle size of aluminum oxide is 18 μm, and the average particle size of zinc oxide is 50 μm.

[0086] The curing material is polyamide 650, with a weight portion of 20 parts.

[0087] In order to verify the advancement of a high temperature resistant insulating varnish and a preparation method thereof provided in the embodiments of the present application, the high temperature resistant insulating varnish provided in Examples 1 to 6 and the insulating varnish provided in Comparative Examples 1 to 4 were prepared on the surface of the insulating core of the temperature measuring wire, and the performance of the obtained insulating varnish was tested. The test results are shown in Table 1 below.

[0088] The verification steps are as follows:

[0089] (1) Prepare insulating paint on the surface of the insulating wire core of the temperature measuring wire:

[0090] ① The selected temperature measuring wire: a layer of wave-proof sleeve, the wave-proof sleeve is woven with stainless steel wire, and the wave-proof sleeve includes two insulating cores and two filling ropes; the two insulating cores and the two filling ropes are twisted into a cable; the two insulating cores are quartz glass fiber yarn woven on the conductor alloy wire.

[0091] ② After mixing the paint and the curing material, apply them on the surface of the insulating core and then cure them; wherein the coating thickness is 25 μm, the curing temperature is 70° C., and the curing time is 40 minutes to obtain the insulating paint.

[0092] (2) According to GB / T 4989-2013, the resistivity of the insulating varnish shall be tested after it is placed in a room temperature environment of 25±1℃ for 10.8h.

[0093] (3) Heat resistance test: According to GB / T 4989-2013 standard, the insulating varnish is placed in a room temperature environment of 200±2℃ for 10.8h and then its resistivity is tested.

[0094] Table 1

[0095] -- <![CDATA[Resistivity at room temperature (×10 15 Ω·cm)]]> <![CDATA[Resistivity at high temperature (×10 13 Ω·cm)]]> Example 1 2.85 1.96 Example 2 2.87 1.97 Example 3 3.01 2.03 Example 4 3.15 2.10 Example 5 3.12 2.05 Example 6 2.98 2.01 Comparative Example 1 2.38 1.29 Comparative Example 2 2.29 1.03 Comparative Example 3 2.33 1.08 Comparative Example 4 2.15 0.96

[0096] From the test results in Table 1 above, at least the following conclusions can be drawn:

[0097] (1) It can be seen from Examples 1 to 6 and Comparative Example 1 that hydrophobic fumed silica can significantly improve the high temperature resistance of insulating varnish. In addition, hydrophobic fumed silica can also improve the wear resistance of insulating varnish, thereby increasing its service life.

[0098] (2) It can be seen from Examples 1 to 6 and Comparative Examples 2 and 3 that modified alumina and modified zinc oxide have a synergistic effect: the amino groups in the modified alumina are hydrogen-bonded with the hydroxyl groups in the modified zinc oxide, so that the modified alumina and modified zinc oxide are cross-linked into a thermally conductive network structure, thereby synergistically improving the high temperature resistance, insulation and thermal conductivity of the high temperature resistant insulating paint.

[0099] (3) It can be seen from Examples 1 to 6 and Comparative Example 4 that the insulating varnish containing modified aluminum oxide and modified zinc oxide has a better thermal conductivity than the insulating varnish directly using aluminum oxide and zinc oxide due to the cross-linked thermal conductive network structure of the modified aluminum oxide and modified zinc oxide and their uniform mixing with the silicone resin without agglomeration.

[0100] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and the embodiments having the same structure as the technical idea and exerting the same effect within the scope of the technical solution of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the main purpose of the present application, various modifications that can be thought of by those skilled in the art to the embodiments and other methods of combining some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A high temperature resistant insulating varnish, characterized in that: The raw materials of the high temperature resistant insulating paint include paint and curing material; the paint includes the following components in parts by weight: 180 parts of organic silicone resin, 20 to 25 parts of hydrophobic fumed silica, 20 to 30 parts of modified aluminum oxide, 15 to 30 parts of modified zinc oxide and 0 to 5 parts of auxiliary agent; The curing material comprises the following raw material components in parts by weight: 20 to 35 parts of amide curing agent.

2. The high temperature resistant insulating varnish according to claim 1, characterized in that: The specific surface area of ​​the hydrophobic fumed silica is 200 m 2 / g~300m 2 / g.

3. The high temperature resistant insulating varnish according to claim 1, characterized in that: The preparation of the modified alumina comprises the following steps: mixing alumina powder and an aminosilane coupling agent and then drying to obtain the modified alumina.

4. The high temperature resistant insulating varnish according to claim 3, characterized in that: The aminosilane coupling agent includes at least one of KH-550, KH-540, KH-792, and A-1100; And / or, the mass ratio of the alumina powder to the aminosilane coupling agent is 2 to 5:

1.

5. The high temperature resistant insulating varnish according to any one of claims 1 to 4, characterized in that: The preparation of the modified zinc oxide comprises the following steps: mixing zinc oxide powder and p-hydroxymethylbenzoic acid and then drying to obtain the modified zinc oxide.

6. The high temperature resistant insulating varnish according to claim 5, characterized in that: The mass ratio of the zinc oxide fine powder to the p-hydroxymethylbenzoic acid is 1 to 5:

1.

7. The high temperature resistant insulating varnish according to claim 6, characterized in that: The average particle size of the modified alumina is 5 μm to 25 μm; And / or, the average particle size of the modified zinc oxide is 40 μm to 85 μm; And / or, the auxiliary agent includes at least one of a dispersant and a leveling agent; And / or, the amide curing agent is polyamide 650.

8. The high temperature resistant insulating varnish according to claim 7, characterized in that: The dispersant is Texaphor963; And / or, the leveling agent is T-306.

9. A method for preparing a high temperature resistant insulating varnish according to any one of claims 1 to 8, characterized in that: The steps include: The paint and curing material are mixed and then cured to obtain the high temperature resistant insulating paint.

10. Use of the high temperature resistant insulating varnish according to any one of claims 1 to 8 in the field of wires and cables.