Preparation method of high-temperature-resistant bending-resistant insulating paint

Abstract

The invention relates to the technical field of insulating paint, and discloses a preparation method of high-temperature-resistant bending-resistant insulating paint, which comprises the following steps: step 1, preparation of high-temperature-resistant resin: taking 6.0-6.2 g of product C, adding 2.3-2.5 g of coupling agent modified zirconium oxide powder and 1.2-1.4 g of product B, and stirring at room temperature for 1.5-2 hours to obtain a uniform mixture, namely the high-temperature-resistant resin; step 2, carbon fiber modification; and step 3, preparing the high-temperature-resistant and bending-resistant insulating paint to obtain the high-temperature-resistant and bending-resistant insulating paint. The high-temperature-resistant resin prepared by the preparation method disclosed by the invention has relatively high thermal stability under extreme conditions; more importantly, even after long-time high-temperature treatment, a paint film formed by the resin can still keep excellent insulating property, strong adhesive force, good flexibility and extensibility (verified by cone bending test) and excellent impact resistance, so that the application range of the resin in a high-temperature environment is greatly widened.

Description

Technical Field

[0001] The invention relates to the technical field of insulating coatings, in particular to a method for preparing a high-temperature-resistant and bending-resistant insulating coating. Background Art

[0002] With the rapid development of industrial technology, the requirements for the stability of metal and non-metal materials in high temperature environments are becoming increasingly stringent, which has directly promoted the rapid expansion of the high temperature resistant insulation coating market. Its application scope has widely covered key industrial fields such as metallurgy, petrochemicals, natural gas extraction, aerospace, etc. However, the high temperature insulation coatings on the current market still face the following challenges and shortcomings:

[0003] 1. Bottleneck of high temperature resistance: Although most coatings are claimed to be resistant to high temperatures, they generally face the problem of a low upper limit of high temperature resistance in actual applications. They are unable to meet the needs of long-term stable operation in extremely high temperature environments, limiting their application potential under higher temperature conditions.

[0004] 2. Insufficient high-temperature performance stability: Some coatings are prone to performance degradation in high-temperature environments, which is manifested in significant decreases in adhesion and increased material embrittlement. This not only affects the protective effect of the coating, but may also damage the substrate, increasing maintenance costs and safety risks.

[0005] 3. It is difficult to take into account all the comprehensive performances: the high-temperature insulation coatings currently on the market often cannot meet the diversified performance requirements of insulation, high temperature resistance, excellent adhesion, good bending strength and corrosion resistance. This phenomenon of "taking care of one thing and losing the other" in performance forces users to make compromises when choosing, and it is difficult to meet the complex and changing needs of industrial applications. Summary of the invention

[0006] The object of the present invention is to provide a method for preparing a high-temperature-resistant and bend-resistant insulating coating to solve the problems raised in the above-mentioned background technology.

[0007] To achieve the above object, the present invention provides the following technical solution: a method for preparing a high-temperature-resistant and bending-resistant insulating coating, comprising the following steps:

[0008] Step 1, preparation of high temperature resistant resin: evacuate the Schlenk flask and fill it with nitrogen, then add 5.6-6.0g of carborane precursor and 500-700mL of solvent into the Schlenk flask to dissolve the carborane precursor in the solvent, then add 100-120mL of acetonitrile, heat and reflux for 4-5h, then add 6.2-6.4g of carbon source, heat and reflux for 16-20h to form an orange-red solution without bubbles, remove the solvent by distillation, and purify by crystallization to obtain product A;

[0009] Another Schlenk flask was evacuated and filled with nitrogen, and then 2.6-2.8 g of product A and 22-25 mL of solvent were added. The Schlenk flask was wrapped with aluminum foil and placed in an ice-water mixture for refrigeration. Then 7.4-7.6 g of carborane precursor was injected into the Schlenk flask, and the reaction was stirred for 24 hours and then poured into ice water. Product B was collected by suction filtration;

[0010] Weigh 3.3-3.5 g of product B and 4.4-4.6 g of 4-cyano-4-biphenylcarboxylic acid into a round-bottom flask, add sulfuric acid as a catalyst, stir until the catalyst is evenly dispersed, heat the mixture to reflux for 7 hours, and separate the organic matter to obtain product C;

[0011] Take 6.0-6.2g of product C, add 2.3-2.5g of coupling agent-modified zirconium oxide powder and 1.2-1.4g of product B, stir at room temperature for 1.5-2h to obtain a uniform mixture, which is a high temperature resistant resin;

[0012] Among them, in order to further improve the temperature resistance limit and stability of the high-temperature resistant resin, zirconium oxide is combined with a specific product C. This combination not only directly improves the high-temperature resistance of the resin, but also provides a key "bridge" for the subsequent construction of more complex and temperature-resistant organic-inorganic hybrid materials, and promotes the close connection and stability of the internal structure of the material, thereby forming a more solid and temperature-resistant composite system.

[0013] Step 2, carbon fiber modification: take 20-25g of carbon fiber and add pure water, submerge the carbon fiber in water, ultrasonically clean for 10-15min, and dry at 110℃ to constant weight;

[0014] Place carbon fiber and 34-36g aluminum hydroxide in a beaker, measure 90-100g phosphoric acid solution, add it to the beaker, stir it with a glass rod to make it evenly paste-like, then add 30-35g water, heat it on an electric furnace until it boils and stir for 10-15min, then put it in an oven for heat treatment, then crush the product with a powder machine, pass it through a 200-mesh sieve, and obtain modified carbon fiber;

[0015] By phosphatizing the carbon fiber, COP bonds were successfully introduced on the surface of the carbon fiber. This step not only effectively blocked the active sites on the surface of the carbon fiber, but also reduced the oxidative catalytic effect of impurity elements on the carbon fiber, thereby significantly improving the antioxidant capacity of the carbon fiber. At the same time, the introduction of phosphate groups and surface grafting treatment also improved the interfacial compatibility between the carbon fiber and the resin, and enhanced the interfacial bonding between the two. This enhanced interfacial bonding is of great significance for improving the overall performance of the composite material, including strength, toughness and durability.

[0016] Step 3, preparation of high-temperature-resistant and anti-bending insulating coating: take 142.5-151.5g of high-temperature-resistant resin, 80-82g of modified carbon fiber and 300-350g of aluminum dihydrogen phosphate in a grinding jar, 1500r / min, ball mill for 1-1.5h to obtain high-temperature-resistant and anti-bending insulating coating.

[0017] As the main framework material, aluminum dihydrogen phosphate forms stable chemical bonds at high temperatures, which not only provides strong bonding force, but also promotes the interaction between fillers and resins through its unique chemical structure, enhancing the compactness and stability of the entire system. The organic resin penetrates into the gaps of the coating, tightly combining the inorganic fillers and inorganic adhesives, which not only improves the flexibility and adhesion of the paint film, but also enhances the anti-permeability and corrosion resistance of the paint film through its cross-linked network structure. In addition, to a certain extent, the organic resin also adjusts the viscosity of the system, making construction more convenient. As a skeleton support, the high-temperature resistant filler increases the hardness and thermal stability of the paint film, while balancing the difference in thermal expansion coefficients between organic and inorganic, making the paint film less likely to deform or crack at high temperatures.

[0018] Among them, in step 2, the specific method of placing in the oven for heat treatment is: first dry the moisture in an oven at 100-110°C, then keep warm at 200°C for 5 minutes, keep warm at 300°C for 10 minutes, and keep warm at 400°C for 10 minutes.

[0019] Wherein, in step 1, the carborane precursor is one or more of diborane, decaborane, borane-8 and boron tribromide.

[0020] Among them, carborane precursors are used as high-performance additives, and ortho-polyhedral cage carborane has been experimentally proven to effectively enhance the thermal properties of various resins. In the present invention, by ingeniously esterifying 4-cyano-4-biphenylcarboxylic acid with carborane, the two work synergistically, not only a new product with excellent thermal, thermomechanical and flame retardant properties is synthesized, but also during the coating curing process, due to the presence of carborane and cyano, a unique organic-inorganic hybrid network system is constructed, which greatly enhances the comprehensive performance of the resin material.

[0021] Wherein, in step 1, the carbon source is one or more of acetylene, 1,2-bis(tributylstannyl)acetylene, butyne, 1,2-bis(4-methoxyphenyl)acetylene and cyclopentenediyne.

[0022] Wherein, in step 1, the solvent is one or more of xylene, dimethyl sulfoxide, acetone, petroleum ether, hexane and dichloromethane.

[0023] Wherein, in step 1, the coupling agent is one or more of isopropyl dioleyl (dioctyl phosphate) titanate, silane coupling agent KH-550, silane coupling agent KH-560, isopropyl tri(dodecylbenzenesulfonic acid) titanate, silane coupling agent KH-792 and isopropyl triisostearate titanate.

[0024] Wherein, in step 2, the fiber diameter of the carbon fiber is 7 μm, the tensile strength is 3450 MPa, and the tensile modulus is 228 GPa.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. The heat-resistant resin prepared by the present invention has a thermal weight loss rate of only 92.26% under extreme conditions (such as 800°C for 5 hours) (compared with conventional resin materials, this value indicates that it has higher thermal stability); more importantly, even after long-term high-temperature treatment, the paint film formed by the resin can still maintain excellent insulation performance, strong adhesion, good flexibility and elongation (verified by cone bending test) and excellent impact resistance, thereby greatly broadening its application range in high-temperature environments;

[0027] 2. This invention abandons the limitations of traditional hybridization methods. Through a carefully designed modification process of the key high-temperature resistant fillers, zirconium oxide and carbon fiber, during the modification process, the filler surface reacts with the hydroxyl (OH-) in the organic resin base material and the inorganic phosphate (such as PO4 3 -) to produce efficient chemical bonding, which not only strengthens the interfacial bonding between the filler and the resin matrix, significantly reduces the defects and gaps between the interfaces, but also promotes the dehydration condensation reaction of aluminum dihydrogen phosphate as an inorganic binder. This innovative strategy constructs a dense composite paint film with aluminum dihydrogen phosphate as the core skeleton, high-temperature fillers and organic film-forming substances tightly filled, which greatly improves the stability and durability of the overall structure;

[0028] 3. The insulating coating prepared by the present invention has achieved significant improvements in high temperature resistance, long-term stability, corrosion resistance, thermal shock tolerance, and bending strength while maintaining excellent insulating properties. These performance improvements make the insulating coating have a wider application prospect in extreme working conditions such as aerospace, automobile manufacturing, energy and electricity, and provide strong support for material upgrades and technological innovations in related industries. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0030] Embodiment 1

[0031] A method for preparing a high-temperature-resistant and bending-resistant insulating coating comprises the following steps:

[0032] Step 1, preparation of high temperature resistant resin: evacuate a 1000mL Schlenk flask and fill it with nitrogen, then add 5.6g of diborane and 500mL of dimethyl sulfoxide into the Schlenk flask to dissolve diborane in dimethyl sulfoxide, then add 120mL of acetonitrile, heat and reflux for 5h, then add 6.3g of acetylene as a carbon source, heat and reflux for 16h to form an orange-red solution without bubbles, remove the solvent by distillation, and purify by crystallization to obtain product A;

[0033] Another 1000 mL Schlenk flask was evacuated and filled with nitrogen, and then 2.7 g of product A and 24 mL of dimethyl sulfoxide were added. The Schlenk flask was wrapped with aluminum foil and placed in an ice-water mixture for refrigeration. Then 7.6 g of diborane was injected into the Schlenk flask. After stirring the reaction for 24 hours, the mixture was poured into ice water and collected by suction filtration to obtain product B.

[0034] 3.3 g of product B and 4.4 g of 4-cyano-4-biphenylcarboxylic acid were weighed and added into a round-bottom flask, sulfuric acid was added as a catalyst, and the mixture was stirred until the catalyst was evenly dispersed. The mixture was heated to reflux for 7 hours, and the organic matter was separated to obtain product C;

[0035] Take 6.0g of product C, add 2.3g of coupling agent-modified zirconium oxide powder and 1.2g of product B, stir at room temperature for 1.5h to obtain a uniform mixture, which is a high temperature resistant resin;

[0036] Step 2, carbon fiber modification: take 23g of carbon fiber and add pure water, submerge the carbon fiber in water, ultrasonically clean for 15min, and dry at 110℃ to constant weight;

[0037] Carbon fiber and 34g aluminum hydroxide are placed in a beaker, 90g of phosphoric acid solution is measured, added to the beaker, and stirred with a glass rod to form a paste, and then 35g of water is added, heated to boiling on an electric furnace and stirred for 15 minutes, and then placed in an oven for heat treatment. The specific method of heat treatment is: first dry the water in an oven at 100-110°C, and then keep warm at 200°C for 5 minutes, keep warm at 300°C for 10 minutes, and keep warm at 400°C for 10 minutes. During the heat treatment, the phosphate undergoes a phase transition to form a white hard shell antioxidant layer, and then the product is crushed with a powder machine and passed through a 200-mesh sieve to obtain a modified carbon fiber;

[0038] Step 3, preparation of high-temperature-resistant and anti-bending insulating coating: take 142.5g of high-temperature-resistant resin, 80g of modified carbon fiber and 300g of aluminum dihydrogen phosphate in a grinding jar, 1500r / min, ball mill for 1h to obtain high-temperature-resistant and anti-bending insulating coating.

[0039] Embodiment 2

[0040] A method for preparing a high-temperature-resistant and bending-resistant insulating coating comprises the following steps:

[0041] Step 1, preparation of high temperature resistant resin: evacuate a 1000mL Schlenk flask and fill it with nitrogen, then add 6.0g of decaborane and 700mL of dimethyl sulfoxide into the Schlenk flask to dissolve the decaborane in dimethyl sulfoxide, then add 120mL of acetonitrile, heat and reflux for 5h, then add 6.4g of 1,2-bis(tributylstannyl)acetylene as a carbon source, heat and reflux for 16h to form an orange-red solution without bubbles, remove the solvent by distillation, and purify by crystallization to obtain product A;

[0042] Another 1000 mL Schlenk flask was evacuated and filled with nitrogen, and then 2.6 g of product A and 25 mL of dimethyl sulfoxide were added. The Schlenk flask was wrapped with aluminum foil and placed in an ice-water mixture for refrigeration. Then 7.6 g of borane-8 was injected into the Schlenk flask, and the reaction was stirred for 24 hours and then poured into ice water. Product B was collected by suction filtration;

[0043] 3.5 g of product B and 4.4 g of 4-cyano-4-biphenylcarboxylic acid were weighed and added into a round-bottom flask, sulfuric acid was added as a catalyst, and the mixture was stirred until the catalyst was evenly dispersed. The mixture was heated to reflux for 7 hours, and the organic matter was separated to obtain product C;

[0044] Take 6.2g of product C, add 2.5g of coupling agent-modified zirconium oxide powder and 1.2g of product B, stir at room temperature for 1.5h to obtain a uniform mixture, which is a high temperature resistant resin;

[0045] Step 2, carbon fiber modification: take 25g of carbon fiber and add pure water, submerge the carbon fiber in water, ultrasonically clean for 15min, and dry at 110℃ to constant weight;

[0046] Carbon fiber and 36g aluminum hydroxide are placed in a beaker, 100g of phosphoric acid solution is measured, added to the beaker, stirred with a glass rod to form a paste, and then 35g of water is added, heated to boiling on an electric furnace and stirred for 15min, and then placed in an oven for heat treatment. The specific method of heat treatment is: first dry the water in an oven at 100-110℃, and then keep warm at 200℃ for 5min, 300℃ for 10min, and 400℃ for 10min. During the heat treatment, the phosphate undergoes a phase transition to form a white hard shell antioxidant layer, and then the product is crushed with a powder machine and passed through a 200-mesh sieve to obtain a modified carbon fiber;

[0047] Step 3, preparation of high-temperature-resistant and flexural-resistant insulating coating: take 142.5g of high-temperature-resistant resin, 82g of modified carbon fiber and 300g of aluminum dihydrogen phosphate in a grinding jar, 1500r / min, ball mill for 1h to obtain high-temperature-resistant and flexural-resistant insulating coating.

[0048] Experimental Example 1: Temperature resistance test of high temperature resistant resin:

[0049] The high temperature resistant resin prepared in Example 1 was coated on the alumina ceramic sheet using a wire rod, first at 80° C. for 20 min and then at 300° C. for 30 min to form a coating, thereby obtaining an alumina ceramic sheet A2.

[0050] Heat resistance test: record the initial weight of a blank alumina ceramic sheet A1 and the initial weight of alumina ceramic sheet A2, keep them at 800℃ for 5h, cool them to room temperature, take them out, and record the weight after the test. The specific weights are as follows:

[0051] Initial weight / g Weight after test / g Change rate % A1 6.2275 6.1579 98.89 A2 6.4065 5.9110 92.26

[0052] It can be seen from the above table that the heat-resistant resin prepared by the present invention has a thermal weight loss rate of only 92.26% under extreme conditions (such as keeping warm at 800°C for 5 hours) (compared with conventional resin materials, this value indicates that it has higher thermal stability).

[0053] Experimental Example 2: Performance test of high temperature resistant and bending resistant insulating coating:

[0054] Preparation of coating: The high temperature resistant and bending resistant insulating coating prepared in Example 1 is coated on tinplate or alumina ceramic sheet with a wire rod, and the curing program is set to heat up to 80°C at 5°C / min and keep warm for 20min, heat up to 200°C at 5°C / min and keep warm for 30min, heat up to 300°C at 5°C / min and keep warm for 60min, and then heat up to 400°C at 5°C / min and keep warm for 30min to cure into coating A3; the performance of coating A3 is tested, and the specific test results are shown in the following table:

[0055]

[0056] It can be seen from the above table that the insulating coating prepared by the present invention has achieved significant improvements in high temperature resistance, long-term stability, corrosion resistance, thermal shock tolerance, and bending strength while maintaining excellent insulating properties. The improvement of these properties makes the insulating coating have a wider application prospect in extreme working conditions such as aerospace, automobile manufacturing, energy and electricity, and provides strong support for material upgrades and technological innovations in related industries.

[0057] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without making any creative work shall fall within the scope of protection of the present invention.

Claims

1. A method for preparing a high-temperature-resistant and bending-resistant insulating coating, characterized in that: The following steps are involved: Step 1, preparation of high temperature resistant resin: evacuate the Schlenk flask and fill it with nitrogen, then add 5.6-6.0g of carborane precursor and 500-700mL of solvent into the Schlenk flask to dissolve the carborane precursor in the solvent, then add 100-120mL of acetonitrile, heat and reflux for 4-5h, then add 6.2-6.4g of carbon source, heat and reflux for 16-20h to form an orange-red solution without bubbles, remove the solvent by distillation, and purify by crystallization to obtain product A; Another Schlenk flask was evacuated and filled with nitrogen, and then 2.6-2.8 g of product A and 22-25 mL of solvent were added. The Schlenk flask was wrapped with aluminum foil and placed in an ice-water mixture for refrigeration. Then 7.4-7.6 g of carborane precursor was injected into the Schlenk flask, and the reaction was stirred for 24 hours and then poured into ice water. Product B was collected by suction filtration; Weigh 3.3-3.5 g of product B and 4.4-4.6 g of 4-cyano-4-biphenylcarboxylic acid into a round-bottom flask, add sulfuric acid as a catalyst, stir until the catalyst is evenly dispersed, heat the mixture to reflux for 7 hours, and separate the organic matter to obtain product C; Take 6.0-6.2g of product C, add 2.3-2.5g of coupling agent-modified zirconium oxide powder and 1.2-1.4g of product B, stir at room temperature for 1.5-2h to obtain a uniform mixture, which is a high temperature resistant resin; Step 2, carbon fiber modification: take 20-25g of carbon fiber and add pure water, submerge the carbon fiber in water, ultrasonically clean for 10-15min, and dry at 110℃ to constant weight; Place carbon fiber and 34-36g aluminum hydroxide in a beaker, measure 90-100g phosphoric acid solution, add it to the beaker, stir it with a glass rod to make it evenly paste-like, then add 30-35g water, heat it on an electric furnace until it boils and stir for 10-15min, then put it in an oven for heat treatment, then crush the product with a powder machine, pass it through a 200-mesh sieve, and obtain modified carbon fiber; Step 3, preparation of high-temperature-resistant and anti-bending insulating coating: take 142.5-151.5g of high-temperature-resistant resin, 80-82g of modified carbon fiber and 300-350g of aluminum dihydrogen phosphate in a grinding jar, 1500r / min, ball mill for 1-1.5h to obtain high-temperature-resistant and anti-bending insulating coating.

2. The method for preparing a high temperature-resistant and bending-resistant insulating coating according to claim 1, characterized in that: In step 2, the specific method of placing in the oven for heat treatment is: first dry the moisture in an oven at 100-110°C, then keep warm at 200°C for 5 minutes, keep warm at 300°C for 10 minutes, and keep warm at 400°C for 10 minutes.

3. The method for preparing a high temperature-resistant and bending-resistant insulating coating according to claim 1, characterized in that: In step 1, the carborane precursor is one or more of diborane, decaborane, borane-8 and boron tribromide.

4. The method for preparing a high temperature-resistant and bending-resistant insulating coating according to claim 1, characterized in that: In step 1, the carbon source is one or more of acetylene, 1,2-bis(tributylstannyl)acetylene, butyne, 1,2-bis(4-methoxyphenyl)acetylene and cyclopentenediyne.

5. The method for preparing a high temperature-resistant and bending-resistant insulating coating according to claim 1, characterized in that: In step 1, the solvent is one or more of xylene, dimethyl sulfoxide, acetone, petroleum ether, hexane and dichloromethane.

6. The method for preparing a high temperature-resistant and bending-resistant insulating coating according to claim 1, characterized in that: In step 1, the coupling agent is one or more of isopropyl dioleyl (dioctyl phosphate) titanate, silane coupling agent KH-550, silane coupling agent KH-560, isopropyl tri(dodecylbenzenesulfonic acid) titanate, silane coupling agent KH-792 and isopropyl triisostearate titanate.

7. The method for preparing a high temperature-resistant and bending-resistant insulating coating according to claim 1, characterized in that: In step 2, the fiber diameter of the carbon fiber is 7 μm, the tensile strength is 3450 MPa, and the tensile modulus is 228 GPa.

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