A flame-retardant, high-temperature-resistant cable coating, and a preparation method and application thereof

Abstract

The application discloses a kind of flame-retardant, high-temperature-resistant cable coating and its preparation method and application, by weight parts, cable coating is prepared from the following raw materials: 60~100 parts epoxy resin, 10~20 parts deionized water, 18~30 parts flame-retardant high-temperature-resistant material, 5~10 parts synergist, 6~15 parts curing agent, 0.3~1 parts leveling agent, 0.3~1 parts defoaming agent.The cable coating provided by the application uses epoxy resin as the main film-forming material, uses flame-retardant high-temperature-resistant material and synergist, and is supplemented by functional film-forming material, so that the prepared cable coating is flame-retardant, high-temperature-resistant, has good comprehensive performance, and is suitable for outdoor cables such as charging piles.

Description

Technical Field

[0001] This invention belongs to the field of coating preparation technology, specifically relating to a flame-retardant, high-temperature resistant cable coating, its preparation method, and its application. Background Technology

[0002] Cables are widely used in production and daily life. Broadly speaking, cables include wires and cables. Taking cables as an example, a conventional cable consists of a core and an outer shell. The outer shell, as the outermost layer of the cable, not only needs to possess excellent physical properties, such as tensile strength and elongation at break, but also good flame-retardant properties. Currently, fire-retardant treatment of cables typically employs the following two methods:

[0003] (1) When preparing cables, flame retardants are added to the raw materials, then mixed and shaped to obtain cables containing flame retardants. This method is complex, and adding flame retardants to the rubber material will affect the properties of the final cable.

[0004] (2) Applying flame retardant to the cable surface during cable preparation. This method is simple and does not affect the properties of the cable. However, if the flame retardant has poor flame retardant effect and poor adhesion, it can easily affect the final fireproof and flame retardant effect.

[0005] Regarding the second treatment method, numerous related coating research reports have been published. For example, patent document CN109370333A provides a flame-retardant coating for cables, whose raw materials, by weight, include the following components: 5-25 parts emulsion, 30-45 parts polyethyleneimine-coated ammonium polyphosphate, 5-20 parts pentaerythritol, 10-15 parts foaming agent, 15-25 parts expandable graphite, 0.01-0.1 parts hydroxyethyl cellulose, 1-3 parts dispersant, and 1-3 parts plasticizer. This flame-retardant coating expands in the event of a fire, forming an expanded carbon layer that prevents oxygen from entering and thus isolates the fire. Simultaneously, by adding plasticizer and hydroxyethyl cellulose, the flame-retardant coating layer applied to the cable surface possesses good mechanical properties, bonds tightly to the cable surface, and does not drip during combustion. However, the specific performance of the flame-retardant coating was not tested in the above technical solution.

[0006] For example, patent document CN112159611A provides a water-based fire-retardant coating for cables and its preparation method, which is prepared from an emulsion, a flame-retardant system, fillers, additives, and water. The flame-retardant system is selected from at least three of pentaerythritol, melamine polyphosphate, ammonium polyphosphate, ammonium polyphosphate, and melamine. In the above technical solution, several flame retardants are directly used, and the flame-retardant performance needs further improvement. Furthermore, the rational formulation of the flame-retardant system is not considered.

[0007] For example, patent document CN118652591A provides a water-based intumescent cable fire-retardant coating and its preparation method. The composition includes the following components and their weight percentages: polyacrylic acid emulsion: 35%-45%, phosphorus-containing expanding agent: 10%-15%, nano-grade silicone tackifier: 2%-4%, polymer surfactant: 1%-1.5%, phosphorus-nitrogen blended flame retardant: 5%-8%, and carbon nanotubes: 0.5%-0.8%. The preferred carbon nanotubes are used as a reinforcing agent to ensure a good balance between fire-retardant and coating performance, meeting the needs of different cable specifications and operating environments. Strict quality control of each raw material ensures the stability and consistency of the coating components, improving product reliability and service life. A high-shear mixer is used for high-speed mixing to ensure thorough and uniform mixing of all components, thereby optimizing the coating's performance and stability. Polyethylene glycol or its derivatives are used as a viscosity modifier to precisely adjust the coating viscosity to adapt to the coating requirements of different cable sizes and shapes, ensuring fluidity and coating thickness control during the coating process. The carbon nanotubes used in the above technical solutions are relatively expensive and not easy to use on a large scale, and the specific flame retardant properties of the coatings have not been tested.

[0008] With the development of the new energy industry, the number of new energy vehicles is increasing, leading to a greater demand for charging. This involves the use of a large amount of cable materials in charging piles and energy storage boxes, many of which are located outdoors and exposed to harsh environments such as high temperatures. Therefore, it is crucial to equip these cables with excellent flame-retardant and high-temperature resistant properties.

[0009] In order to achieve the above objectives, this invention is proposed. Summary of the Invention

[0010] To address the shortcomings of existing technologies, the present invention aims to provide a flame-retardant and high-temperature resistant cable coating, its preparation method, and its application, which exhibits good flame-retardant and high-temperature resistant properties and excellent overall performance.

[0011] To achieve the above objectives, the present invention adopts the following technical solution:

[0012] In a first aspect, the present invention provides a flame-retardant and high-temperature resistant cable coating, which is prepared by weight from the following raw materials: 60-100 parts epoxy resin, 10-20 parts deionized water, 18-30 parts flame-retardant and high-temperature resistant material, 5-10 parts synergist, 6-15 parts curing agent, 0.3-1 part leveling agent, and 0.3-1 part defoamer;

[0013] The preparation of flame-retardant and high-temperature resistant materials includes the following steps:

[0014] S11. Prepare an aqueous solution of cyanoamine for later use;

[0015] S12. Mix straw powder and montmorillonite evenly, then add it to the cyanoamine aqueous solution obtained in step S11, and perform ultrasonic impregnation treatment; after treatment, separate and dry to obtain the composite material.

[0016] S13. The composite material obtained in step S12 is placed in an inert atmosphere for calcination; after calcination, it is cooled, ground and sieved to obtain the modified composite material.

[0017] S14. The modified composite material obtained in step S13 is added to an organophosphorus flame retardant for immersion. After immersion, it is separated and dried to obtain a flame-retardant and high-temperature resistant material.

[0018] As a preferred embodiment of the technical solution of the present invention, in step S11, the concentration of the cyanoamine aqueous solution is 0.05~0.2g / mL;

[0019] In step S12, the straw is either wheat straw or peanut straw; the mass ratio of straw to montmorillonite is 1:0.8~1.2; the volume ratio of straw to cyanoamine aqueous solution is 1g:6~10mL; the ultrasonic impregnation power is 50~150W, and the treatment time is 0.5~4h.

[0020] As a preferred embodiment of the technical solution of the present invention, in step S13, the inert atmosphere is helium; the calcination temperature is 480~510℃, the calcination time is 0.5~4h; and the grinding and sieving mesh size is 150~250 mesh.

[0021] In step S14, the organophosphorus flame retardant is dimethyl methyl phosphate; the mass ratio of the modified composite material to the organophosphorus flame retardant is 1:3~6; the immersion temperature is room temperature, and the immersion time is 8~16h.

[0022] As a preferred embodiment of the technical solution of the present invention, the preparation of the synergist includes the following steps:

[0023] S21. Wash the fly ash with water, dry it, add it to an ammonium dihydrogen phosphate solution, heat and stir, then filter and calcine; after calcine, pretreated fly ash is obtained.

[0024] S22. Add the pretreated fly ash obtained in step S21 to a potassium permanganate solution and heat and stir; then filter and calcine; after the treatment is completed, wash and dry to obtain modified fly ash.

[0025] S23. Add the modified fly ash obtained in step S22 to water and stir at 80~95℃ for 1~4h to obtain a suspension. Continue heating and stirring, and then add sodium hydroxide solution and magnesium chloride solution dropwise to the obtained suspension. After the addition is completed, continue stirring at 80~95℃ for 0.5~2h. Then filter, wash and dry to obtain the synergist.

[0026] As a preferred embodiment of the present invention, in step S21, the concentration of the ammonium dihydrogen phosphate solution is 0.4~0.8g / L; the ratio of fly ash to ammonium dihydrogen phosphate solution is 1g:30~50mL; the heating and stirring treatment temperature is 35~45℃, the treatment time is 8~16h; the calcination temperature is 750~800℃, and the calcination time is 0.5~2h.

[0027] As a preferred embodiment of the technical solution of the present invention, in step S22, the concentration of potassium permanganate solution is 5~10wt%, the ratio of pretreated fly ash to potassium permanganate solution is 1g:1.5~2.5mL; the heating and stirring treatment temperature is 45~60℃, the treatment time is 4~8h; the calcination temperature is 450~520℃, and the calcination time is 2~6h.

[0028] As a preferred embodiment of the technical solution of the present invention, in step S23, the mass ratio of modified fly ash to water is 1:3~8; the concentration of sodium hydroxide solution is 0.05~0.2mol / L, and the concentration of magnesium chloride solution is 0.1~0.35mol / L; the dropping rate of both sodium hydroxide solution and magnesium chloride solution is 0.5~1.5mL / min; and the coating amount of magnesium hydroxide on the surface of modified fly ash is 0.8~1.5%.

[0029] As a preferred embodiment of the present invention, the curing agent is a polyamide curing agent; the leveling agent is BYK-349; and the defoamer is BYK-024.

[0030] Secondly, the present invention provides a method for preparing the above-mentioned flame-retardant and high-temperature resistant cable coating, comprising the following steps: mixing epoxy resin, flame-retardant and high-temperature resistant material and synergist and stirring, then adding deionized water and defoamer, and stirring again; then adding curing agent and leveling agent, and stirring again, and the coating is ready.

[0031] Thirdly, the present invention provides the application of the above-mentioned flame-retardant and high-temperature resistant cable coating in cables of new energy vehicles, charging guns or energy storage boxes.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] (1) The present invention provides a flame-retardant and high-temperature resistant cable coating, which uses epoxy resin as the main film-forming substance, combined with flame-retardant and high-temperature resistant materials and synergists, and supplemented with functional film-forming substances, so that the prepared cable coating has good flame-retardant and high-temperature resistant properties and excellent comprehensive performance, and is suitable for use in outdoor cables such as charging piles.

[0034] (2) In this invention, the flame-retardant and high-temperature resistant material uses straw powder and montmorillonite as the main raw materials. After loading cyanoamine, it is subjected to pyrolysis treatment. After calcination, the straw forms biochar material. Biochar has a porous structure. The loaded cyanoamine is decomposed by high-temperature calcination, which can achieve nitrogen doping of biochar. This improves the flame-retardant performance of biochar material and also helps to improve the adsorption capacity of dimethyl methyl phosphate, further improving the flame-retardant performance. Montmorillonite itself is a very good flame-retardant and high-temperature resistant material, but it usually has poor dispersibility in resin. Therefore, in this invention, it is calcined together with straw and modified with cyanoamine. Before high-temperature decomposition, the adsorption of cyanoamine between montmorillonite layers helps to expand the interlayer spacing of montmorillonite. After high-temperature calcination, the decomposition of cyanoamine helps to further expand the interlayer spacing of montmorillonite, improve the adsorption capacity and surface activity of montmorillonite, and also improve the adsorption capacity of dimethyl methyl phosphate.

[0035] Meanwhile, the combined use of montmorillonite and straw-based biochar can greatly improve the material's high-temperature resistance and flame retardancy compared to using the above materials alone.

[0036] (3) In this invention, a small amount of synergist is also used to improve the flame retardancy and high-temperature resistance of the coating. The synergist uses fly ash as the main raw material. Fly ash itself has good high-temperature resistance, but it does not have flame retardancy. In this invention, it is first modified with ammonium dihydrogen phosphate, which is beneficial to initially improve the flame retardancy of fly ash and increase the specific surface area of ​​fly ash. Then, the fly ash is treated with potassium permanganate, which is beneficial to further improve the specific surface area of ​​fly ash and also to increase the acidic oxygen-containing functional groups on the surface of fly ash. Obviously, the modification with ammonium dihydrogen phosphate and potassium permanganate mentioned above is beneficial to improve the coating effect of magnesium on the surface of fly ash, thereby improving the flame retardancy and high-temperature resistance of the synergist. In addition, the introduction of magnesium hydroxide is beneficial to synergistically improve the flame retardancy of the synergist with fly ash.

[0037] (4) In this invention, the combined use of flame-retardant and high-temperature resistant materials and synergists, through the loaded dimethyl methyl phosphate (organophosphorus flame retardant) and magnesium hydroxide (inorganic flame retardant), combined with the use of montmorillonite, fly ash and straw, promotes the improvement of the flame retardant and high-temperature resistant properties of epoxy resin in multiple dimensions and in a synergistic manner.

[0038] (5) The cable coating preparation process provided by the present invention is simple and can be obtained by simple stirring, which is easy to implement. Detailed Implementation

[0039] The embodiments of the present invention are described in detail below. All embodiments are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0040] In this invention, by way of example, the epoxy resin is E51 epoxy resin, which was purchased from Shandong Chuangying Chemical Co., Ltd.

[0041] The polyamide curing agent, grade 650, with an amine value of approximately 200, was purchased from Jinan Zhiheng Zhiyuan Chemical Technology Co., Ltd.

[0042] Cyanamide, CAS number 461-58-5;

[0043] Montmorillonite was purchased from Shunze Mineral Products Processing Plant in Lingshou County;

[0044] Dimethyl methyl phosphate, CAS number 756-79-6;

[0045] The fly ash was purchased from Shanghai Greenia Nanomaterials Co., Ltd., and its main components are SiO2 and Al2O3, with mass fractions of approximately 56% and 28%, respectively.

[0046] It should be noted that the weight parts or weights mentioned in this invention are examples, and those skilled in the art can scale up production according to the proportions.

[0047] Example 1

[0048] A flame-retardant and high-temperature resistant cable coating is prepared by weight from the following raw materials: 90g E51 epoxy resin, 10g deionized water, 20g flame-retardant and high-temperature resistant material, 5g synergist, 12g 650 polyamide curing agent, 0.5g BYK-349, and 0.5g BYK-024.

[0049] The preparation of flame-retardant and high-temperature resistant materials includes the following steps:

[0050] S11. Prepare a cyanoamine aqueous solution with a concentration of 0.1 g / mL for later use;

[0051] S12. Mix 2mm long wheat straw with montmorillonite at a mass ratio of 1:1, then add it to the cyanoamine aqueous solution obtained in step S11, and ultrasonically impregnate (100W, 1h); after treatment, separate and dry to obtain the composite material; wherein, the ratio of wheat straw to cyanoamine aqueous solution is 1g:8mL;

[0052] S13. The composite material obtained in step S12 is placed in an argon inert atmosphere for calcination (495℃, 1h); after calcination, it is cooled, ground and sieved through a 200-mesh sieve to obtain the modified composite material.

[0053] S14. The modified composite material obtained in step S13 is added to dimethyl methyl phosphate and soaked (at room temperature, for 12 hours) at a mass ratio of 1:4. After soaking, it is separated and dried to obtain the flame-retardant and high-temperature resistant material.

[0054] The preparation of the synergist includes the following steps:

[0055] S21. Wash the fly ash with water, dry it, and add it to a 0.55 g / L ammonium dihydrogen phosphate solution. Heat and stir the mixture (40 °C, 10 h), then filter and calcine (780 °C, 0.5 h). After calcination, pretreated fly ash is obtained. The ratio of fly ash to ammonium dihydrogen phosphate solution is 1 g: 40 mL.

[0056] S22. According to the dosage ratio of 1g:2mL, the pretreated fly ash obtained in step S21 is added to an 8wt% potassium permanganate solution and heated and stirred (50℃, 5h); then filtered and calcined (495℃, 2.5h); after the treatment is completed, it is washed and dried to obtain modified fly ash.

[0057] S23. The modified fly ash obtained in step S22 is added to water at a mass ratio of 1:5, and stirred at 90°C for 2 hours to obtain a suspension. While maintaining heating and stirring, 0.1 mol / L sodium hydroxide solution and 0.2 mol / L magnesium chloride solution are simultaneously added dropwise to the obtained suspension at a rate of 1 mL / min. After the addition is completed, the mixture is stirred at 90°C for 1 hour. Then, it is filtered, washed, and dried to obtain the synergist. The magnesium hydroxide coating mass on the surface of the modified fly ash is 1%.

[0058] In this embodiment, a method for preparing the above-mentioned cable coating is also provided, comprising the following steps: mixing E51 epoxy resin, flame-retardant and high-temperature resistant material, and synergist and stirring, then adding deionized water and BYK-024, and stirring again; then adding 650 polyamide curing agent and BYK-349, and stirring again, and the coating is ready.

[0059] Example 2

[0060] A flame-retardant and high-temperature resistant cable coating is prepared by weight from the following raw materials: 90g E51 epoxy resin, 11g deionized water, 18g flame-retardant and high-temperature resistant material, 5.5g synergist, 12.5g 650 polyamide curing agent, 0.45g BYK-349, and 0.45g BYK-024.

[0061] The preparation of flame-retardant and high-temperature resistant materials includes the following steps:

[0062] S11. Prepare a cyanoamine aqueous solution with a concentration of 0.11 g / mL for later use;

[0063] S12. Mix 2mm long wheat straw with montmorillonite at a mass ratio of 1:0.9, then add it to the cyanoamine aqueous solution obtained in step S11, and ultrasonically impregnate (80W, 1.5h); after treatment, separate and dry to obtain the composite material; wherein, the ratio of wheat straw to cyanoamine aqueous solution is 1g:9mL;

[0064] S13. The composite material obtained in step S12 is placed in an argon inert atmosphere for calcination (500℃, 1h); after calcination, it is cooled, ground and sieved through a 200-mesh sieve to obtain the modified composite material.

[0065] S14. The modified composite material obtained in step S13 is added to dimethyl methyl phosphate and soaked (at room temperature, 11h) at a mass ratio of 1:4. After soaking, it is separated and dried to obtain the flame-retardant and high-temperature resistant material.

[0066] The preparation of the synergist includes the following steps:

[0067] S21. Wash the fly ash with water, dry it, and add it to a 0.5 g / L ammonium dihydrogen phosphate solution. Heat and stir the mixture (40 °C, 9 h), then filter and calcine (785 °C, 0.5 h). After calcination, pretreated fly ash is obtained. The ratio of fly ash to ammonium dihydrogen phosphate solution is 1 g: 40 mL.

[0068] S22. According to the dosage ratio of 1g:2mL, the pretreated fly ash obtained in step S21 is added to an 8wt% potassium permanganate solution and heated and stirred (50℃, 5h); then filtered and calcined (495℃, 2.5h); after the treatment is completed, it is washed and dried to obtain modified fly ash.

[0069] S23. The modified fly ash obtained in step S22 is added to water at a mass ratio of 1:4, and stirred at 90°C for 2 hours to obtain a suspension. While maintaining heating and stirring, 0.12 mol / L sodium hydroxide solution and 0.22 mol / L magnesium chloride solution are simultaneously added dropwise to the obtained suspension at a rate of 1 mL / min. After the addition is completed, the mixture is stirred at 90°C for 1 hour. Then, it is filtered, washed, and dried to obtain the synergist. The magnesium hydroxide coating mass on the surface of the modified fly ash is 1%.

[0070] In this embodiment, a method for preparing the above-mentioned cable coating is also provided, comprising the following steps: mixing E51 epoxy resin, flame-retardant and high-temperature resistant material, and synergist and stirring, then adding deionized water and BYK-024, and stirring again; then adding 650 polyamide curing agent and BYK-349, and stirring again, and the coating is ready.

[0071] Example 3

[0072] A flame-retardant and high-temperature resistant cable coating is prepared by weight from the following raw materials: 90g E51 epoxy resin, 11g deionized water, 22g flame-retardant and high-temperature resistant material, 4.5g synergist, 12g 650 polyamide curing agent, 0.55g BYK-349, and 0.45g BYK-024.

[0073] The preparation of flame-retardant and high-temperature resistant materials includes the following steps:

[0074] S11. Prepare a cyanoamine aqueous solution with a concentration of 0.11 g / mL for later use;

[0075] S12. Mix 2mm long wheat straw with montmorillonite at a mass ratio of 1:1.1, then add it to the cyanoamine aqueous solution obtained in step S11, and ultrasonically impregnate (90W, 1.5h). After treatment, separate and dry to obtain the composite material. The ratio of wheat straw to cyanoamine aqueous solution is 1g:9mL.

[0076] S13. The composite material obtained in step S12 is placed in an argon inert atmosphere for calcination (500℃, 1h); after calcination, it is cooled, ground and sieved through a 200-mesh sieve to obtain the modified composite material.

[0077] S14. The modified composite material obtained in step S13 is added to dimethyl methyl phosphate and soaked (at room temperature, for 10 hours) at a mass ratio of 1:4. After soaking, it is separated and dried to obtain the flame-retardant and high-temperature resistant material.

[0078] The preparation of the synergist includes the following steps:

[0079] S21. Wash the fly ash with water, dry it, and add it to a 0.5 g / L ammonium dihydrogen phosphate solution. Heat and stir the mixture (40 °C, 9 h), then filter and calcine (790 °C, 0.5 h). After calcination, pretreated fly ash is obtained. The ratio of fly ash to ammonium dihydrogen phosphate solution is 1 g: 35 mL.

[0080] S22. According to the dosage ratio of 1g:2mL, the pretreated fly ash obtained in step S21 is added to an 8wt% potassium permanganate solution and heated and stirred (45℃, 5h); then filtered and calcined (495℃, 2.5h); after the treatment is completed, it is washed and dried to obtain modified fly ash.

[0081] S23. The modified fly ash obtained in step S22 is added to water at a mass ratio of 1:4, and stirred at 90°C for 2 hours to obtain a suspension. While maintaining heating and stirring, 0.11 mol / L sodium hydroxide solution and 0.22 mol / L magnesium chloride solution are simultaneously added dropwise to the obtained suspension at a rate of 1 mL / min. After the addition is completed, the mixture is stirred at 85°C for 1 hour. Then, it is filtered, washed, and dried to obtain the synergist. The magnesium hydroxide coating mass on the surface of the modified fly ash is 1%.

[0082] In this embodiment, a method for preparing the above-mentioned cable coating is also provided, comprising the following steps: mixing E51 epoxy resin, flame-retardant and high-temperature resistant material, and synergist and stirring, then adding deionized water and BYK-024, and stirring again; then adding 650 polyamide curing agent and BYK-349, and stirring again, and the coating is ready.

[0083] Comparative Example 1

[0084] Compared with Example 1, the use of synergist was omitted in Comparative Example 1, and all other aspects were the same. Specifically, this comparative example provides a flame-retardant and high-temperature resistant cable coating, which is prepared by weight from the following raw materials: 90g E51 epoxy resin, 10g deionized water, 20g flame-retardant and high-temperature resistant material, 12g 650 polyamide curing agent, 0.5g BYK-349, and 0.5g BYK-024.

[0085] The preparation of flame-retardant and high-temperature resistant materials includes the following steps:

[0086] S11. Prepare a cyanoamine aqueous solution with a concentration of 0.1 g / mL for later use;

[0087] S12. Mix 2mm long wheat straw with montmorillonite at a mass ratio of 1:1, then add it to the cyanoamine aqueous solution obtained in step S11, and ultrasonically impregnate (100W, 1h); after treatment, separate and dry to obtain the composite material; wherein, the ratio of wheat straw to cyanoamine aqueous solution is 1g:8mL;

[0088] S13. The composite material obtained in step S12 is placed in an argon inert atmosphere for calcination (495℃, 1h); after calcination, it is cooled, ground and sieved through a 200-mesh sieve to obtain the modified composite material.

[0089] S14. The modified composite material obtained in step S13 is added to dimethyl methyl phosphate and soaked (at room temperature, for 12 hours) at a mass ratio of 1:4. After soaking, it is separated and dried to obtain the flame-retardant and high-temperature resistant material.

[0090] This comparative example also provides a method for preparing the above-mentioned cable coating, comprising the following steps: mixing E51 epoxy resin and flame-retardant high-temperature resistant material and stirring, then adding deionized water and BYK-024, and stirring again; then adding 650 polyamide curing agent and BYK-349, and stirring again, and the coating is ready.

[0091] Comparative Example 2

[0092] Compared with Example 1, the potassium permanganate treatment was omitted in Comparative Example 2, and all other steps were the same. Specifically, this comparative example provides a flame-retardant and high-temperature resistant cable coating, which is prepared by weight from the following raw materials: 90g E51 epoxy resin, 10g deionized water, 20g flame-retardant and high-temperature resistant material, 5g synergist, 12g 650 polyamide curing agent, 0.5g BYK-349, and 0.5g BYK-024.

[0093] The preparation of flame-retardant and high-temperature resistant materials includes the following steps:

[0094] S11. Prepare a cyanoamine aqueous solution with a concentration of 0.1 g / mL for later use;

[0095] S12. Mix 2mm long wheat straw with montmorillonite at a mass ratio of 1:1, then add it to the cyanoamine aqueous solution obtained in step S11, and ultrasonically impregnate (100W, 1h); after treatment, separate and dry to obtain the composite material; wherein, the ratio of wheat straw to cyanoamine aqueous solution is 1g:8mL;

[0096] S13. The composite material obtained in step S12 is placed in an argon inert atmosphere for calcination (495℃, 1h); after calcination, it is cooled, ground and sieved through a 200-mesh sieve to obtain the modified composite material.

[0097] S14. The modified composite material obtained in step S13 is added to dimethyl methyl phosphate and soaked (at room temperature, for 12 hours) at a mass ratio of 1:4. After soaking, it is separated and dried to obtain the flame-retardant and high-temperature resistant material.

[0098] The preparation of the synergist includes the following steps:

[0099] S21. Wash the fly ash with water, dry it, and add it to a 0.55 g / L ammonium dihydrogen phosphate solution. Heat and stir the mixture (40 °C, 10 h), then filter and calcine (780 °C, 0.5 h). After calcination, pretreated fly ash is obtained. The ratio of fly ash to ammonium dihydrogen phosphate solution is 1 g: 40 mL.

[0100] S22. The pretreated fly ash obtained in step S21 is added to water at a mass ratio of 1:5 and stirred at 90°C for 2 hours to obtain a suspension. While maintaining heating and stirring, 0.1 mol / L sodium hydroxide solution and 0.2 mol / L magnesium chloride solution are added dropwise to the obtained suspension at a rate of 1 mL / min. After the addition is completed, the suspension is stirred at 90°C for 1 hour. Then, the suspension is filtered, washed, and dried to obtain the synergist. The magnesium hydroxide coating mass on the surface of the pretreated fly ash is 1%.

[0101] This comparative example also provides a method for preparing the above-mentioned cable coating, comprising the following steps: mixing E51 epoxy resin, flame-retardant and high-temperature resistant material, and synergist and stirring, then adding deionized water and BYK-024, and stirring again; then adding 650 polyamide curing agent and BYK-349, and stirring again, and the coating is ready.

[0102] Comparative Example 3

[0103] Compared to Example 1, the preparation of the flame-retardant and high-temperature resistant material in Comparative Example 3 omits the cyanoamine treatment, while all other steps remain the same. Specifically, this comparative example provides a flame-retardant and high-temperature resistant cable coating, prepared by weight from the following raw materials: 90g E51 epoxy resin, 10g deionized water, 20g flame-retardant and high-temperature resistant material, 5g synergist, 12g 650 polyamide curing agent, 0.5g BYK-349, and 0.5g BYK-024.

[0104] The preparation of flame-retardant and high-temperature resistant materials includes the following steps:

[0105] S11. Mix 2mm long wheat straw with montmorillonite at a mass ratio of 1:1 to obtain a composite material;

[0106] S12. The composite material obtained in step S11 is calcined in an argon inert atmosphere (495℃, 1h); after calcination, it is cooled, ground and sieved through a 200-mesh sieve to obtain the modified composite material.

[0107] S13. The modified composite material obtained in step S12 is added to dimethyl methyl phosphate and soaked (at room temperature, for 12 hours) at a mass ratio of 1:4. After soaking, the material is separated and dried to obtain the flame-retardant and high-temperature resistant material.

[0108] The preparation of the synergist includes the following steps:

[0109] S21. Wash the fly ash with water, dry it, and add it to a 0.55 g / L ammonium dihydrogen phosphate solution. Heat and stir the mixture (40 °C, 10 h), then filter and calcine (780 °C, 0.5 h). After calcination, pretreated fly ash is obtained. The ratio of fly ash to ammonium dihydrogen phosphate solution is 1 g: 40 mL.

[0110] S22. According to the dosage ratio of 1g:2mL, the pretreated fly ash obtained in step S21 is added to an 8wt% potassium permanganate solution and heated and stirred (50℃, 5h); then filtered and calcined (495℃, 2.5h); after the treatment is completed, it is washed and dried to obtain modified fly ash.

[0111] S23. The modified fly ash obtained in step S22 is added to water at a mass ratio of 1:5, and stirred at 90°C for 2 hours to obtain a suspension. While maintaining heating and stirring, 0.1 mol / L sodium hydroxide solution and 0.2 mol / L magnesium chloride solution are simultaneously added dropwise to the obtained suspension at a rate of 1 mL / min. After the addition is completed, the mixture is stirred at 90°C for 1 hour. Then, it is filtered, washed, and dried to obtain the synergist. The magnesium hydroxide coating mass on the surface of the modified fly ash is 1%.

[0112] This comparative example also provides a method for preparing the above-mentioned cable coating, comprising the following steps: mixing E51 epoxy resin, flame-retardant and high-temperature resistant material, and synergist and stirring, then adding deionized water and BYK-024, and stirring again; then adding 650 polyamide curing agent and BYK-349, and stirring again, and the coating is ready.

[0113] Comparative Example 4

[0114] In this comparative example, the use of montmorillonite is omitted, and all other aspects are the same. Specifically, this comparative example provides a flame-retardant and high-temperature resistant cable coating, which is prepared by weight from the following raw materials: 90g E51 epoxy resin, 10g deionized water, 20g flame-retardant and high-temperature resistant material, 5g synergist, 12g 650 polyamide curing agent, 0.5g BYK-349, and 0.5g BYK-024.

[0115] The preparation of flame-retardant and high-temperature resistant materials includes the following steps:

[0116] S11. Prepare a cyanoamine aqueous solution with a concentration of 0.1 g / mL for later use;

[0117] S12. Add 2mm long wheat straw to the cyanoamine aqueous solution obtained in step S11 and ultrasonically impregnate it (100W, 1h). After treatment, separate and dry to obtain the composite material. The ratio of wheat straw to cyanoamine aqueous solution is 1g:8mL.

[0118] S13. The composite material obtained in step S12 is placed in an argon inert atmosphere for calcination (495℃, 1h); after calcination, it is cooled, ground and sieved through a 200-mesh sieve to obtain the modified composite material.

[0119] S14. The modified composite material obtained in step S13 is added to dimethyl methyl phosphate and soaked (at room temperature, for 12 hours) at a mass ratio of 1:4. After soaking, it is separated and dried to obtain the flame-retardant and high-temperature resistant material.

[0120] The preparation of the synergist includes the following steps:

[0121] S21. Wash the fly ash with water, dry it, and add it to a 0.55 g / L ammonium dihydrogen phosphate solution. Heat and stir the mixture (40 °C, 10 h), then filter and calcine (780 °C, 0.5 h). After calcination, pretreated fly ash is obtained. The ratio of fly ash to ammonium dihydrogen phosphate solution is 1 g: 40 mL.

[0122] S22. According to the dosage ratio of 1g:2mL, the pretreated fly ash obtained in step S21 is added to an 8wt% potassium permanganate solution and heated and stirred (50℃, 5h); then filtered and calcined (495℃, 2.5h); after the treatment is completed, it is washed and dried to obtain modified fly ash.

[0123] S23. The modified fly ash obtained in step S22 is added to water at a mass ratio of 1:5, and stirred at 90°C for 2 hours to obtain a suspension. While maintaining heating and stirring, 0.1 mol / L sodium hydroxide solution and 0.2 mol / L magnesium chloride solution are simultaneously added dropwise to the obtained suspension at a rate of 1 mL / min. After the addition is completed, the mixture is stirred at 90°C for 1 hour. Then, it is filtered, washed, and dried to obtain the synergist. The magnesium hydroxide coating mass on the surface of the modified fly ash is 1%.

[0124] This comparative example also provides a method for preparing the above-mentioned cable coating, comprising the following steps: mixing E51 epoxy resin, flame-retardant and high-temperature resistant material, and synergist and stirring, then adding deionized water and BYK-024, and stirring again; then adding 650 polyamide curing agent and BYK-349, and stirring again, and the coating is ready.

[0125] The cable coatings prepared in Example 1 and Comparative Examples 1-4 were subjected to performance testing, and the specific methods are as follows:

[0126] The cable coatings prepared in Examples 1 and Comparative Examples 1-4 were applied to the surface of commercially available cables (cleaned and dry) until the coating thickness reached approximately 1 mm (coatings can be applied in multiple coats, allowing each coat to dry completely before proceeding). The coatings were then allowed to dry completely. The limiting oxygen index was tested according to ASTM D2863-10; the vertical burning performance was tested according to ASTM D3801-10; and the coating adhesion was tested according to ASTM D 3359-09.

[0127] The heat resistance of cable coatings shall be determined in accordance with GB / T 1735-2009.

[0128] The test results are shown in Table 1.

[0129] Table 1 Test Results

[0130]

[0131] As can be seen from Table 1, the cable coating provided by the present invention has good flame retardancy, high temperature resistance, strong adhesion, and excellent overall performance.

[0132] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A flame-retardant, high-temperature resistant cable coating, characterized in that, It is prepared by weight from the following raw materials: 60-100 parts epoxy resin, 10-20 parts deionized water, 18-30 parts flame retardant and high temperature resistant material, 5-10 parts synergist, 6-15 parts curing agent, 0.3-1 part leveling agent, and 0.3-1 part defoamer. The preparation of flame-retardant and high-temperature resistant materials includes the following steps: S11. Prepare an aqueous solution of cyanoamine for later use; S12. Mix straw and montmorillonite evenly, then add it to the cyanoamine aqueous solution obtained in step S11, and perform ultrasonic impregnation treatment; after treatment, separate and dry to obtain the composite material. S13. The composite material obtained in step S12 is placed in an inert atmosphere for calcination; after calcination, it is cooled, ground and sieved to obtain the modified composite material. S14. The modified composite material obtained in step S13 is added to an organophosphorus flame retardant for immersion. After immersion, it is separated and dried to obtain a flame-retardant and high-temperature resistant material. The preparation of the synergist includes the following steps: S21. Wash the fly ash with water, dry it, add it to an ammonium dihydrogen phosphate solution, heat and stir, then filter and calcine; after calcine, pretreated fly ash is obtained. S22. Add the pretreated fly ash obtained in step S21 to a potassium permanganate solution and heat and stir; then filter and calcine; after the treatment is completed, wash and dry to obtain modified fly ash. S23. Add the modified fly ash obtained in step S22 to water and stir at 80~95℃ for 1~4h to obtain a suspension. Continue heating and stirring, and then add sodium hydroxide solution and magnesium chloride solution dropwise to the obtained suspension. After the addition is completed, continue stirring at 80~95℃ for 0.5~2h. Then filter, wash and dry to obtain the synergist.

2. The flame-retardant and high-temperature resistant cable coating according to claim 1, characterized in that, In step S11, the concentration of the cyanoamine aqueous solution is 0.05~0.2 g / mL; In step S12, the straw is either wheat straw or peanut straw; the mass ratio of straw to montmorillonite is 1:0.8~1.2; the volume ratio of straw to cyanoamine aqueous solution is 1g:6~10mL; the ultrasonic impregnation power is 50~150W, and the treatment time is 0.5~4h.

3. The flame-retardant and high-temperature resistant cable coating according to claim 1, characterized in that, In step S13, the inert atmosphere is helium; the calcination temperature is 480~510℃, the calcination time is 0.5~4h; and the grinding and sieving mesh size is 150~250 mesh. In step S14, the organophosphorus flame retardant is dimethyl methyl phosphate; the mass ratio of the modified composite material to the organophosphorus flame retardant is 1:3~6; the immersion temperature is room temperature, and the immersion time is 8~16h.

4. The flame-retardant and high-temperature resistant cable coating according to claim 1, characterized in that, In step S21, the concentration of the ammonium dihydrogen phosphate solution is 0.4~0.8 g / L; the ratio of fly ash to ammonium dihydrogen phosphate solution is 1 g: 30~50 mL; the heating and stirring treatment temperature is 35~45℃, the treatment time is 8~16 h; the calcination temperature is 750~800℃, and the calcination time is 0.5~2 h.

5. The flame-retardant and high-temperature resistant cable coating according to claim 1, characterized in that, In step S22, the concentration of potassium permanganate solution is 5~10wt%, the ratio of pretreated fly ash to potassium permanganate solution is 1g:1.5~2.5mL; the heating and stirring treatment temperature is 45~60℃, the treatment time is 4~8h; the calcination temperature is 450~520℃, and the calcination time is 2~6h.

6. The flame-retardant and high-temperature resistant cable coating according to claim 1, characterized in that, In step S23, the mass ratio of modified fly ash to water is 1:3~8; the concentration of sodium hydroxide solution is 0.05~0.2mol / L, and the concentration of magnesium chloride solution is 0.1~0.35mol / L; the dropping rate of both sodium hydroxide solution and magnesium chloride solution is 0.5~1.5mL / min; and the coating amount on the surface of modified fly ash is 0.8~1.5%.

7. The flame-retardant and high-temperature resistant cable coating according to claim 1, characterized in that, The curing agent is a polyamide curing agent; The leveling agent is BYK-349; The defoamer is BYK-024.

8. A method for preparing a flame-retardant, high-temperature resistant cable coating according to any one of claims 1 to 7, characterized in that, The process includes the following steps: mixing epoxy resin, flame-retardant and high-temperature resistant material, and synergist, then adding deionized water and defoamer, and stirring again; then adding curing agent and leveling agent, and stirring again.

9. The application of the flame-retardant and high-temperature resistant cable coating according to any one of claims 1 to 7 in the cables of new energy vehicles, charging guns or energy storage boxes.

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