Flame-retardant and high-temperature-resistant cable coating as well as preparation method and application thereof

Abstract

The invention discloses a flame-retardant and high-temperature-resistant cable coating as well as a preparation method and application thereof, and the cable coating is prepared from the following raw materials in parts by weight: 60-100 parts of epoxy resin, 10-20 parts of deionized water, 18-30 parts of a flame-retardant and high-temperature-resistant material, 5-10 parts of a synergist, 6-15 parts of a curing agent, 0.3-1 part of a flatting agent and 0.3-1 part of a defoaming agent. According to the cable coating provided by the invention, the epoxy resin is used as a main film-forming substance, is matched with the flame-retardant and high-temperature-resistant material and the synergist for use, and is supplemented with the functional film-forming substance, so that the prepared cable coating is good in flame retardance and high-temperature resistance and excellent in comprehensive performance, and is suitable for outdoor cables such as charging piles.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of coating preparation, and particularly relates to a flame-retardant and high-temperature-resistant cable coating as well as a preparation method and application thereof. BACKGROUND

[0002] Cables are widely used in production and life. In a broad sense, cables include electric wires and cables. Taking cables as an example, a conventional cable is composed of a cable core and a shell. The shell as the outermost layer of the cable needs to have excellent physical properties such as tensile strength and elongation at break, and also needs to have good flame-retardant properties. At present, for the fireproof and flame-retardant treatment of cables, the following two forms are usually adopted: (1) When preparing the cable, a flame retardant is added to the raw material, and then mixed, formed, and prepared into a cable containing the flame retardant. This treatment has a complex process, and after adding the flame retardant to the rubber material, the properties of the final cable are affected.

[0003] (2) When preparing the cable, the surface of the cable is brushed or coated with a flame retardant. This process is simple and does not affect the properties of the cable, but if the flame retardant has poor flame-retardant effect and poor adhesion, it will easily affect the final fireproof and flame-retardant effect.

[0004] For the second treatment method, there are many related coating research reports. For example, patent document CN109370333A provides a flame-retardant coating for cables, which includes the following components by weight: emulsion 5-25 parts, polyethylene imine-coated ammonium polyphosphate 30-45 parts, pentaerythritol 5-20 parts, foaming agent 10-15 parts, expandable graphite 15-25 parts, hydroxyethyl cellulose 0.01-0.1 parts, dispersant 1-3 parts, and plasticizer 1-3 parts. The above-mentioned flame-retardant coating expands when a fire occurs, forming an expanded carbon layer to prevent oxygen from entering and isolating the fire. At the same time, by adding a plasticizer and hydroxyethyl cellulose, the flame-retardant coating layer brushed on the surface of the cable has good mechanical properties and is tightly combined with the surface of the cable, and does not drip during combustion. In the above technical solution, the specific performance of the flame-retardant coating is not tested.

[0005] For example, patent document CN112159611A provides a water-based cable fireproof coating and a preparation method thereof, which is prepared from emulsion, a flame-retardant system, fillers, additives, and water. The flame-retardant system is selected from at least three of pentaerythritol, melamine polyphosphate, polyphosphoric acid ammonium, ammonium polyphosphate, and melamine. In the above technical solution, several flame retardants are directly used, and the flame-retardant performance needs to be further improved, and the rationalization of the flame-retardant system is not considered.

[0006] For example, patent document CN118652591A provides a water-based intumescent cable fireproof coating and a preparation method thereof. The composition includes the following components and their weight percentages: polyacrylic emulsion: 35%-45%, phosphorus-containing intumescent agent: 10%-15%, nanoscale silica gel tackifier: 2%-4%, polymeric interfacial surfactant: 1%-1.5%, phosphorus-nitrogen blended flame retardant: 5%-8%, and carbon nanotube: 0.5%-0.8%. The preferred carbon nanotube is used as a reinforcing agent to ensure a good balance between fireproof performance and coating performance, which can meet the needs of different cable specifications and use environments. By strictly controlling the quality of each raw material, the stability and consistency of the coating composition are ensured, and the reliability and service life of the product are improved. High-speed mixing is performed using a high-shear mixer to ensure that the components are thoroughly mixed and evenly distributed, thereby optimizing the performance and stability of the coating. Polyethylene glycol or its derivatives are used as viscosity modifiers to accurately adjust the viscosity of the coating to meet the coating needs of different cable sizes and shapes, ensuring the flowability and coating thickness control during the coating process. In the above technical solution, the carbon nanotube used has a relatively high cost and is not easy to scale up, and the specific flame retardant performance of the coating has not been tested.

[0007] With the development of the new energy industry, the number of new energy vehicles is increasing, and the demand for charging is also increasing. Among them, a large number of cable materials are used in charging piles and energy storage boxes, and many of these cable materials are located outdoors and are subjected to harsh environments such as high temperatures. Therefore, it is very important to endow the cable material with excellent flame retardant and high-temperature resistant properties.

[0008] To achieve the above purpose, the present application is proposed. SUMMARY

[0009] In view of the deficiencies of the prior art, the present application aims to provide a flame-retardant and high-temperature-resistant cable coating, a preparation method and application thereof, which has good flame-retardant and high-temperature-resistant properties and excellent comprehensive performance.

[0010] To achieve the above purpose, the present application adopts the following technical solutions: In a first aspect, the present application provides a flame-retardant and high-temperature-resistant cable coating, which is prepared from the following raw materials in parts by weight: 60-100 parts of epoxy resin, 10-20 parts of deionized water, 18-30 parts of flame-retardant and high-temperature-resistant material, 5-10 parts of synergist, 6-15 parts of curing agent, 0.3-1 part of leveling agent, and 0.3-1 part of defoaming agent. The preparation of the flame-retardant and high-temperature-resistant material includes the following steps: S11, preparing a cyanamide aqueous solution for standby use; S12, the straw powder is mixed with the montmorillonite uniformly, and then is added into the cyanamine aqueous solution obtained in the step S11 to be treated by ultrasonic immersion; after the treatment is completed, the treatment by separation and drying is performed to obtain a composite material; S13, the composite material obtained in the step S12 is placed in an inert atmosphere to be calcined; after the calcination is completed, the composite material is cooled, ground and sieved to obtain a modified composite material; S14, the modified composite material obtained in the step S13 is added into an organic phosphorus-based flame retardant to be soaked; after the soaking is completed, the treatment by separation and drying is performed to obtain a high-temperature resistant flame-retardant material.

[0011] As a preferred technical scheme of the present application, in the step S11, the concentration of the cyanamine aqueous solution is 0.05-0.2 g / mL; In the step S12, the straw is one of wheat straw and peanut straw; the mass ratio of the straw to the montmorillonite is 1:0.8-1.2; the usage ratio of the straw to the cyanamine aqueous solution is 1 g:6-10 mL; the power of the ultrasonic immersion treatment is 50-150 W, and the treatment time is 0.5-4 h.

[0012] As a preferred technical scheme of the present application, in the step S13, the inert atmosphere is a helium atmosphere; the calcination temperature is 480-510℃, the calcination time is 0.5-4 h, and the mesh size of the grinding and sieving is 150-250 mesh; In the step S14, the organic phosphorus-based flame retardant is dimethyl methylphosphonate; the mass ratio of the modified composite material to the organic phosphorus-based flame retardant is 1:3-6; the soaking temperature is room temperature, and the soaking time is 8-16 h.

[0013] As a preferred technical scheme of the present application, the preparation of the synergist includes the following steps: S21, the fly ash is washed with water, dried, and then added into an ammonium dihydrogen phosphate solution to be treated by heating and stirring; then, the fly ash is filtered and calcined to obtain pretreated fly ash; S22, the pretreated fly ash obtained in the step S21 is added into a potassium permanganate solution to be treated by heating and stirring; then, the fly ash is filtered and calcined; after the treatment is completed, the treatment by washing and drying is performed to obtain modified fly ash; S23, the modified fly ash obtained in the step S22 is added into water to be stirred at 80-95℃ for 1-4 h to obtain a suspension; the stirring is continued while heating, then sodium hydroxide solution and magnesium chloride solution are simultaneously added dropwise into the suspension; after the dropwise addition is completed, the stirring is continued at 80-95℃ for 0.5-2 h; then, the treatment by filtration, washing and drying is performed to obtain a synergist.

[0014] As a preferred technical scheme of the present application, in step S21, the concentration of the ammonium dihydrogen phosphate solution is 0.4-0.8 g / L; the ratio of the use amount of fly ash to the use amount of the ammonium dihydrogen phosphate solution is 1 g:30-50 mL; the heating and stirring treatment temperature is 35-45℃, and the treatment time is 8-16 h; the calcination temperature is 750-800℃, and the calcination time is 0.5-2 h.

[0015] As a preferred technical scheme of the present application, in step S22, the concentration of the potassium permanganate solution is 5-10 wt%, the ratio of the use amount of the pretreated fly ash to the use amount of the potassium permanganate solution is 1 g:1.5-2.5 mL; the heating and stirring treatment temperature is 45-60℃, and the treatment time is 4-8 h; the calcination temperature is 450-520℃, and the calcination time is 2-6 h.

[0016] As a preferred technical scheme of the present application, in step S23, the mass ratio of the modified fly ash to water is 1:3-8; the concentration of the sodium hydroxide solution is 0.05-0.2 mol / L, and the concentration of the magnesium chloride solution is 0.1-0.35 mol / L; the dropping speed of the sodium hydroxide solution and the magnesium chloride solution is both 0.5-1.5 mL / min; and the coating amount of magnesium hydroxide on the surface of the modified fly ash is 0.8-1.5%.

[0017] As a preferred technical scheme of the present application, the curing agent is a polyamide curing agent; the leveling agent is BYK-349; and the defoaming agent is BYK-024.

[0018] In a second aspect, the present application provides a preparation method of the above-mentioned flame-retardant and high-temperature-resistant cable coating, which comprises the following steps: mixing an epoxy resin, a flame-retardant and high-temperature-resistant material, and a synergist, and then stirring; subsequently adding deionized water and a defoaming agent, and then stirring; and then adding a curing agent and a leveling agent, and then stirring again.

[0019] In a third aspect, the present application provides an application of the above-mentioned flame-retardant and high-temperature-resistant cable coating in a new energy automobile, a charging gun or a cable for an energy storage box.

[0020] Compared with the prior art, the present application has the following beneficial effects: (1) The flame-retardant and high-temperature-resistant cable coating provided by the present application uses an epoxy resin as a main film-forming material, and uses a flame-retardant and high-temperature-resistant material and a synergist in combination, and is supplemented by a functional film-forming material, so that the prepared cable coating has good flame-retardant and high-temperature-resistant properties, and has good comprehensive performance, and is suitable for use in outdoor cables such as charging piles.

[0021] (2) In the present application, the flame-retardant high-temperature-resistant material takes straw powder and montmorillonite as main raw materials, is loaded with cyanamine, and then is pyrolyzed; the straw is formed into biochar material after calcination, the biochar has a porous structure, the loaded cyanamine is decomposed by high-temperature calcination, nitrogen doping of the biochar can be realized, the flame-retardant performance of the biochar material is improved, and the adsorption capacity of subsequent dimethyl methylphosphonate is improved, and the flame-retardant performance is further improved; the montmorillonite is a very good flame-retardant and high-temperature-resistant material itself, but the dispersibility in resin is usually poor, so the montmorillonite is calcined together with the straw in the present application, and is modified by cyanamine, the adsorption of cyanamine between the montmorillonite before high-temperature decomposition is beneficial to the expansion of the interlayer spacing of the montmorillonite, and the decomposition of cyanamine after high-temperature calcination is beneficial to the further expansion of the interlayer spacing of the montmorillonite, the adsorption capacity and surface activity of the montmorillonite are improved, and the adsorption capacity of subsequent dimethyl methylphosphonate is also improved; Meanwhile, the composite use of the montmorillonite and the straw-based biochar can greatly improve the high-temperature resistance and the flame-retardant performance of the material compared with the use of the above-mentioned material alone.

[0022] (3) In the present application, a small amount of synergist is also used to improve the flame-retardant and high-temperature-resistant performance of the coating. The synergist takes fly ash as main raw material, the fly ash has good high-temperature resistance, but does not have flame-retardant performance, the fly ash is modified by ammonium dihydrogen phosphate in the present application, which is beneficial to the preliminary improvement of the flame-retardant performance of the fly ash and the increase of the specific surface area of the fly ash; then the fly ash is treated by potassium permanganate, which is beneficial to the further increase of the specific surface area of the fly ash and the increase of the acidic oxygen-containing functional groups on the surface of the fly ash. Obviously, through the modification of ammonium dihydrogen phosphate and potassium permanganate, the coating effect of magnesium on the surface of the fly ash is improved, and the flame-retardant and high-temperature-resistant performance of the synergist is improved; in addition, the introduction of magnesium hydroxide is beneficial to the improvement of the flame-retardant performance of the synergist in cooperation with the fly ash.

[0023] (4) In the present application, the flame-retardant high-temperature-resistant material and the synergist are used together, the loaded dimethyl methylphosphonate (organic phosphorus flame retardant) and magnesium hydroxide (inorganic flame retardant) are used in cooperation with the montmorillonite, the fly ash and the straw, and the flame-retardant and high-temperature-resistant performance of the epoxy resin is improved in multiple dimensions and synergistically.

[0024] (5) The cable coating provided by the present application is simple to prepare and can be obtained by simple stirring, and is easy to implement. DETAILED DESCRIPTION

[0025] The embodiments of the present application are described in detail below, all the embodiments are exemplary and are intended to explain the present application, and cannot be understood as a limitation of the present application.

[0026] In the present application, the epoxy resin is E51 epoxy resin, which is purchased from Shandong Chuangying Chemical Co., Ltd. The polyamide curing agent is 650, the amine value is about 200, and is purchased from Jinan Zhichengyuan Chemical Technology Co., Ltd.; Cyanamide, CAS No. 461-58-5; Montmorillonite is purchased from Shunze Mineral Product Processing Factory in Lingshou County; Methyl dimethyl phosphate, CAS No. 756-79-6; Fly ash is purchased from Shanghai Gelun Yana Nanometer Material Co., Ltd., and the main components are SiO2 and Al2O3, and the mass fractions are about 56% and 28% respectively.

[0027] It should be particularly pointed out that the weight parts or weights mentioned in the present application are examples, and those skilled in the art can scale up production according to the proportion.

[0028] Example 1 A flame-retardant and high-temperature-resistant cable coating is prepared from the following raw materials by weight: 90g of E51 epoxy resin, 10g of deionized water, 20g of flame-retardant and high-temperature-resistant material, 5g of synergist, 12g of 650 polyamide curing agent, 0.5g of BYK-349, and 0.5g of BYK-024.

[0029] Preparation of the flame-retardant and high-temperature-resistant material includes the following steps: S11, prepare a cyanamide aqueous solution with a concentration of 0.1g / mL for standby; S12, mix 2mm long wheat straw and montmorillonite uniformly at a mass ratio of 1:1, then add them into the cyanamide aqueous solution obtained in step S11, and perform ultrasonic immersion treatment (100W, 1h); after the treatment, separate and dry the treated material to obtain a composite material; wherein the usage ratio of wheat straw and cyanamide aqueous solution is 1g:8mL; S13, place the composite material obtained in step S12 in an argon inert atmosphere for calcination (495℃, 1h); after the calcination, cool and grind the treated material to pass a 200 mesh sieve to obtain a modified composite material; S14, according to a mass ratio of 1:4, add the modified composite material obtained in step S13 into methyl dimethyl phosphate for soaking (room temperature, 12h); after the soaking, separate and dry the treated material to obtain the flame-retardant and high-temperature-resistant material.

[0030] Preparation of the synergist includes the following steps: S21, wash the fly ash with water, dry, and then add it into a 0.55g / L ammonium dihydrogen phosphate solution, and perform heating and stirring treatment (40℃, 10h); then filter and calcine (780℃, 0.5h); after the calcination, obtain pretreated fly ash; the usage ratio of fly ash and ammonium dihydrogen phosphate solution is 1g:40mL; S22, according to the 1g:2mL of the use ratio, the pretreated fly ash obtained in step S21 is added to the 8wt% concentration of potassium permanganate solution, heated and stirred (50℃, 5h); then filtration, calcination treatment (495℃, 2.5h) is carried out; after the treatment is completed, washing, drying treatment is carried out, and the modified fly ash is obtained; S23, according to the mass ratio 1:5, the modified fly ash obtained in step S22 is added to water, and a suspension is obtained after stirring at 90℃ for 2h; keep heating and stirring, then 0.1mol / L sodium hydroxide solution and 0.2mol / L magnesium chloride solution are added to the obtained suspension at the same time, the dropping speed is 1mL / min, after the dropping is completed, continue to stir at 90℃ for 1h, then filtration, washing, drying treatment is carried out, and the synergist is obtained; wherein the coating mass of magnesium hydroxide on the surface of the modified fly ash is 1%.

[0031] In this embodiment, a preparation method of the above cable coating is also provided, which comprises the following steps: mixing E51 epoxy resin, flame-retardant high-temperature-resistant material and synergist, then stirring, then adding deionized water and BYK-024, and then stirring; then adding 650 polyamide curing agent and BYK-349, and stirring again.

[0032] Example 2 A flame-retardant and high-temperature-resistant cable coating is prepared from the following raw materials by weight: 90g of E51 epoxy resin, 11g of deionized water, 18g of flame-retardant high-temperature-resistant material, 5.5g of synergist, 12.5g of 650 polyamide curing agent, 0.45g of BYK-349, and 0.45g of BYK-024.

[0033] Preparation of the flame-retardant high-temperature-resistant material comprises the following steps: S11, prepare a 0.11g / mL concentration of cyanamide aqueous solution for use; S12, mix 2mm long wheat straw and montmorillonite in a mass ratio of 1:0.9, then add to the cyanamide aqueous solution obtained in step S11, and ultrasonic immersion treatment (80W, 1.5h); after the treatment is completed, separate and dry to obtain a composite material; wherein the use ratio of wheat straw and cyanamide aqueous solution is 1g:9mL; S13, place the composite material obtained in step S12 in an argon inert atmosphere and calcine (500℃, 1h); after calcination is completed, cool, grind and sieve to 200 meshes to obtain a modified composite material; S14, according to the mass ratio 1:4, the modified composite material obtained in step S13 is soaked in methyl phosphonate dimethyl ester (room temperature, 11h), after soaking is completed, separate and dry to obtain the flame-retardant high-temperature-resistant material.

[0034] The preparation of the synergist includes the following steps: S21, washing the fly ash with water, drying, and then adding to 0.5 g / L of ammonium dihydrogen phosphate solution, heating and stirring treatment (40℃, 9h), followed by filtration and calcination (785℃, 0.5h); after calcination, the pretreated fly ash is obtained; the dosage ratio of fly ash and ammonium dihydrogen phosphate solution is 1g:40mL; S22, according to the dosage ratio of 1g:2mL, the pretreated fly ash obtained in step S21 is added to 8wt% concentration of potassium permanganate solution, heating and stirring treatment (50℃, 5h); then filtration and calcination treatment (495℃, 2.5h) are carried out; after treatment, washing and drying treatment are carried out, and the modified fly ash is obtained; S23, according to the mass ratio of 1:4, the modified fly ash obtained in step S22 is added to water, and a suspension is obtained after stirring at 90℃ for 2h; keeping heating and stirring, then 0.12mol / L sodium hydroxide solution and 0.22mol / L magnesium chloride solution are added to the obtained suspension at the same time, the dropping speed is 1mL / min, after the dropping is completed, continue to stir at 90℃ for 1h, then filtration, washing and drying treatment are carried out, and the synergist is obtained; wherein the coating mass of magnesium hydroxide on the surface of the modified fly ash is 1%.

[0035] In this embodiment, a preparation method of the above cable coating is also provided, which includes the following steps: mixing E51 epoxy resin, flame-retardant high-temperature-resistant material and synergist, then stirring, then adding deionized water and BYK-024, and then stirring; then adding 650 polyamide curing agent and BYK-349, and stirring again.

[0036] Example 3 A flame-retardant and high-temperature-resistant cable coating is prepared from the following raw materials by weight: 90g E51 epoxy resin, 11g deionized water, 22g flame-retardant high-temperature-resistant material, 4.5g synergist, 12g 650 polyamide curing agent, 0.55g BYK-349, and 0.45g BYK-024.

[0037] The preparation of the flame-retardant high-temperature-resistant material includes the following steps: S11, preparing 0.11g / mL concentration of cyanamide aqueous solution for standby; S12, mixing 2mm long wheat straw and montmorillonite according to the mass ratio of 1:1.1, then adding to the cyanamide aqueous solution obtained in step S11, and ultrasonic immersion treatment (90W, 1.5h); after treatment, separation and drying treatment are carried out, and the composite material is obtained; wherein the dosage ratio of wheat straw and cyanamide aqueous solution is 1g:9mL; S13, the composite material obtained in step S12 is placed in an argon inert atmosphere for calcination (500℃, 1h); after calcination, cooling, grinding and sieving 200 mesh treatment, a modified composite material is obtained; S14, the modified composite material obtained in step S13 is added to dimethyl methylphosphonate according to a mass ratio of 1:4 for soaking (room temperature, 10h); after soaking, separation and drying treatment, a flame-retardant high-temperature-resistant material is obtained.

[0038] The preparation of the synergist includes the following steps: S21, the fly ash is washed with water, dried and added to a 0.5g / L ammonium dihydrogen phosphate solution, heated and stirred (40℃, 9h), then filtered and calcined (790℃, 0.5h); after calcination, pretreated fly ash is obtained; the dosage ratio of fly ash to ammonium dihydrogen phosphate solution is 1g:35mL; S22, the pretreated fly ash obtained in step S21 is added to a 8wt% potassium permanganate solution according to a dosage ratio of 1g:2mL, heated and stirred (45℃, 5h); then filtered and calcined (495℃, 2.5h); after treatment, washed and dried, modified fly ash is obtained; S23, the modified fly ash obtained in step S22 is added to water according to a mass ratio of 1:4, a suspension is obtained after stirring at 90℃ for 2h; maintaining heating and stirring, then 0.11mol / L sodium hydroxide solution and 0.22mol / L magnesium chloride solution are simultaneously added dropwise to the obtained suspension at a dropwise speed of 1mL / min, after dropwise addition, continue stirring at 85℃ for 1h, then filtered, washed and dried to obtain a synergist; wherein the coating mass of magnesium hydroxide on the surface of the modified fly ash is 1%.

[0039] In this embodiment, a preparation method of the above-mentioned cable coating is also provided, which includes the following steps: mixing E51 epoxy resin, flame-retardant high-temperature-resistant material and synergist, then stirring, then adding deionized water and BYK-024, and then stirring; then adding 650 polyamide curing agent and BYK-349, and stirring again.

[0040] Comparative Example 1 Compared with Example 1, the use of synergist is omitted in Comparative Example 1, and the rest is the same. Specifically, in this comparative example, a flame-retardant and high-temperature-resistant cable coating is provided, which is prepared from the following raw materials by weight: 90g E51 epoxy resin, 10g deionized water, 20g flame-retardant high-temperature-resistant material, 12g 650 polyamide curing agent, 0.5g BYK-349, and 0.5g BYK-024.

[0041] The preparation of the flame-retardant high-temperature-resistant material includes the following steps: S11, prepare a cyanic acid aqueous solution with a concentration of 0.1 g / mL for standby; S12, mix 2 mm long wheat straw and montmorillonite uniformly according to a mass ratio of 1:1, and then add to the cyanic acid aqueous solution obtained in step S11 for ultrasonic immersion treatment (100 W, 1 h); after the treatment is completed, separate and dry to obtain a composite material; wherein the usage ratio of the wheat straw and the cyanic acid aqueous solution is 1 g:8 mL; S13, place the composite material obtained in step S12 in an argon inert atmosphere for calcination (495℃, 1 h); after the calcination is completed, cool, grind and sieve to 200 meshes to obtain a modified composite material; S14, according to a mass ratio of 1:4, add the modified composite material obtained in step S13 to dimethyl methylphosphonate for soaking (room temperature, 12 h); after the soaking is completed, separate and dry to obtain a flame-retardant high-temperature-resistant material.

[0042] In the present comparative example, a preparation method of the above-mentioned cable coating is also provided, which comprises the following steps: mix E51 epoxy resin and the flame-retardant high-temperature-resistant material, and then stir, and then add deionized water and BYK-024, and then stir; then add 650 polyamide curing agent and BYK-349, and then stir again.

[0043] Comparative Example 2 Compared with Example 1, the treatment of potassium permanganate is omitted in Comparative Example 2, and the rest is the same. Specifically, in the present comparative example, a flame-retardant and high-temperature-resistant cable coating is provided, which is prepared from the following raw materials by weight: 90 g of E51 epoxy resin, 10 g of deionized water, 20 g of flame-retardant high-temperature-resistant material, 5 g of synergist, 12 g of 650 polyamide curing agent, 0.5 g of BYK-349, and 0.5 g of BYK-024.

[0044] The preparation of the flame-retardant high-temperature-resistant material comprises the following steps: S11, prepare a cyanic acid aqueous solution with a concentration of 0.1 g / mL for standby; S12, mix 2 mm long wheat straw and montmorillonite uniformly according to a mass ratio of 1:1, and then add to the cyanic acid aqueous solution obtained in step S11 for ultrasonic immersion treatment (100 W, 1 h); after the treatment is completed, separate and dry to obtain a composite material; wherein the usage ratio of the wheat straw and the cyanic acid aqueous solution is 1 g:8 mL; S13, place the composite material obtained in step S12 in an argon inert atmosphere for calcination (495℃, 1 h); after the calcination is completed, cool, grind and sieve to 200 meshes to obtain a modified composite material; S14, the modified composite material obtained in step S13 is added into dimethyl methylphosphonate according to a mass ratio of 1:4 for soaking (room temperature, 12 h), and after the soaking is completed, the flame-retardant high-temperature-resistant material is obtained through separation and drying treatment.

[0045] The preparation of the synergist includes the following steps: S21, the fly ash is washed with water, dried, and then added into a 0.55 g / L ammonium dihydrogen phosphate solution for heating and stirring treatment (40℃, 10 h), followed by filtration and calcination (780℃, 0.5 h); after the calcination is completed, the pretreated fly ash is obtained; the dosage ratio of the fly ash to the ammonium dihydrogen phosphate solution is 1 g:40 mL; S22, the pretreated fly ash obtained in step S21 is added into water according to a mass ratio of 1:5, and a suspension is obtained after stirring at 90℃ for 2 h; while maintaining the heating and stirring, 0.1 mol / L sodium hydroxide solution and 0.2 mol / L magnesium chloride solution are simultaneously added dropwise into the obtained suspension at a dropwise adding speed of 1 mL / min; after the dropwise adding is completed, the stirring treatment is continued at 90℃ for 1 h, and then the synergist is obtained through filtration, washing, and drying treatment; wherein, the coating mass of magnesium hydroxide on the surface of the pretreated fly ash is 1%.

[0046] In the present comparative example, a preparation method of the above-mentioned cable coating is also provided, which includes the following steps: the E51 epoxy resin, the flame-retardant high-temperature-resistant material, and the synergist are mixed and stirred, then deionized water and BYK-024 are added, and then stirring is carried out; then 650 polyamide curing agent and BYK-349 are added, and after stirring again, the preparation is completed.

[0047] Comparative Example 3 Compared with Example 1, the preparation of the flame-retardant high-temperature-resistant material in Comparative Example 3 omits the cyanamide treatment, and the rest is the same. Specifically, in the present comparative example, a flame-retardant high-temperature-resistant cable coating is provided, which is prepared from the following raw materials by weight: 90 g of E51 epoxy resin, 10 g of deionized water, 20 g of flame-retardant high-temperature-resistant material, 5 g of synergist, 12 g of 650 polyamide curing agent, 0.5 g of BYK-349, and 0.5 g of BYK-024.

[0048] The preparation of the flame-retardant high-temperature-resistant material includes the following steps: S11, wheat straw with a length of 2 mm is uniformly mixed with montmorillonite according to a mass ratio of 1:1 to obtain a composite material; S12, the composite material obtained in step S11 is calcined in an argon inert atmosphere (495℃, 1 h); after the calcination is completed, the modified composite material is obtained through cooling, grinding, and sieving to 200 mesh; S13, the modified composite material obtained in step S12 is added into dimethyl methylphosphonate according to a mass ratio of 1:4 for soaking (room temperature, 12 h), after the soaking is completed, the flame-retardant high-temperature-resistant material is obtained through separation and drying treatment.

[0049] The preparation of the synergist includes the following steps: S21, the fly ash is washed with water, dried and then added into a 0.55 g / L ammonium dihydrogen phosphate solution, heated and stirred (40℃, 10 h), then filtered and calcined (780℃, 0.5 h); after the calcination is completed, the pretreated fly ash is obtained; the dosage ratio of the fly ash and the ammonium dihydrogen phosphate solution is 1 g:40 mL; S22, the pretreated fly ash obtained in step S21 is added into a 8 wt% potassium permanganate solution according to a dosage ratio of 1 g:2 mL, heated and stirred (50℃, 5 h); then filtered and calcined (495℃, 2.5 h); after the treatment is completed, the modified fly ash is obtained through washing and drying treatment; S23, the modified fly ash obtained in step S22 is added into water according to a mass ratio of 1:5, a suspension is obtained after being stirred at 90℃ for 2 h; the heating and stirring are maintained, then 0.1 mol / L sodium hydroxide solution and 0.2 mol / L magnesium chloride solution are simultaneously added dropwise into the obtained suspension at a dropping speed of 1 mL / min, after the dropwise addition is completed, the stirring is continued at 90℃ for 1 h, then the synergist is obtained through filtration, washing and drying treatment; wherein, the coating mass of magnesium hydroxide on the surface of the modified fly ash is 1%.

[0050] In the present comparative example, a preparation method of the above-mentioned cable coating is also provided, which includes the following steps: the E51 epoxy resin, the flame-retardant high-temperature-resistant material and the synergist are mixed and stirred, then deionized water and BYK-024 are added and stirred; then 650 polyamide curing agent and BYK-349 are added and stirred again.

[0051] Comparative Example 4 In the present comparative example, the use of montmorillonite is omitted and the rest is the same. Specifically, in the present comparative example, a flame-retardant high-temperature-resistant cable coating is provided, which is prepared from the following raw materials by weight: 90 g of E51 epoxy resin, 10 g of deionized water, 20 g of flame-retardant high-temperature-resistant material, 5 g of synergist, 12 g of 650 polyamide curing agent, 0.5 g of BYK-349, and 0.5 g of BYK-024.

[0052] The preparation of the flame-retardant high-temperature-resistant material includes the following steps: S11, a 0.1 g / mL concentration of cyanamide aqueous solution is prepared and reserved; S12, 2mm long wheat straw is added to the cyanic acid amine aqueous solution obtained in step S11, and ultrasonic immersion treatment is performed (100W, 1h); after the treatment is completed, the composite material is obtained through separation and drying treatment; wherein the dosage ratio of the wheat straw and the cyanic acid amine aqueous solution is 1g:8mL; S13, the composite material obtained in step S12 is placed in an argon inert atmosphere for calcination (495℃, 1h); after the calcination is completed, the modified composite material is obtained through cooling, grinding and sieving to 200 meshes; S14, the modified composite material obtained in step S13 is added to dimethyl methylphosphonate in a mass ratio of 1:4 for soaking (room temperature, 12h); after the soaking is completed, the flame-retardant high-temperature-resistant material is obtained through separation and drying treatment.

[0053] The preparation of the synergist includes the following steps: S21, the fly ash is washed with water, dried and then added to a 0.55g / L ammonium dihydrogen phosphate solution, and heated and stirred (40℃, 10h); then filtered and calcined (780℃, 0.5h); after the calcination is completed, the pretreated fly ash is obtained; the dosage ratio of the fly ash and the ammonium dihydrogen phosphate solution is 1g:40mL; S22, the pretreated fly ash obtained in step S21 is added to a 8wt% potassium permanganate solution in a dosage ratio of 1g:2mL, and heated and stirred (50℃, 5h); then filtered and calcined (495℃, 2.5h); after the treatment is completed, the modified fly ash is obtained through washing and drying treatment; S23, the modified fly ash obtained in step S22 is added to water in a mass ratio of 1:5, and a suspension is obtained after stirring at 90℃ for 2h; the heating and stirring are maintained, and then 0.1mol / L sodium hydroxide solution and 0.2mol / L magnesium chloride solution are simultaneously added dropwise to the obtained suspension at a dropwise speed of 1mL / min; after the dropwise addition is completed, the stirring is continued at 90℃ for 1h; then the synergist is obtained through filtration, washing and drying treatment; wherein the coating mass of magnesium hydroxide on the surface of the modified fly ash is 1%.

[0054] In the present comparative example, a preparation method of the above-mentioned cable coating is also provided, which includes the following steps: E51 epoxy resin, flame-retardant high-temperature-resistant material and synergist are mixed and stirred, then deionized water and BYK-024 are added and stirred; then 650 polyamide curing agent and BYK-349 are added and stirred again.

[0055] The cable coatings prepared in Example 1 and Comparative Examples 1-4 are subjected to performance tests, and the specific method is as follows: The cable coating prepared in Example 1 and Comparative Examples 1-4 was brushed on the surface of commercially available cable (cleaned and kept dry) until the coating thickness was about 1 mm (the coating can be applied in several times, and the coating should be dried before the next coating), and then dried. The limiting oxygen index was tested according to ASTM D2863-10; the UL-94 vertical burning performance was tested according to ASTM D3801-10; and the coating adhesion was tested according to ASTM D 3359-09.

[0056] The heat resistance of the cable coating was tested according to GB / T 1735-2009.

[0057] The test results are shown in Table 1.

[0058] Table 1 Test results

[0059] As can be seen from Table 1, the cable coating provided by the present application has good flame retardant and high temperature resistant properties, strong adhesion, and good comprehensive performance.

[0060] Although the embodiments of the present application have been shown and described, it is to be understood that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present application, and the scope of the present application 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.

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, The preparation of synergists 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 the potassium permanganate solution and heat and stir. Then it undergoes filtration and calcination. After processing, modified fly ash is obtained through washing and drying. 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.

5. The flame-retardant and high-temperature resistant cable coating according to claim 4, characterized in that, In step S21, the concentration of 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.

6. The flame-retardant and high-temperature resistant cable coating according to claim 4, 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.

7. 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%.

8. 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.

9. A method for preparing a flame-retardant, high-temperature resistant cable coating according to any one of claims 1 to 8, 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.

10. The application of the flame-retardant and high-temperature resistant cable coating according to any one of claims 1 to 8 in the cables of new energy vehicles, charging guns or energy storage boxes.

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