Preparation method of composite coated flame retardant and composite coated flame retardant

Abstract

The embodiment of the present disclosure provides a preparation method of a composite coated flame retardant and a composite coated flame retardant, which relates to the technical field of flame retardants and fire retardant coatings. The method includes: dissolving ammonium polyphosphate in an ethanol aqueous solution and stirring at a first temperature, and adding a hydroxymethyl melamine solution and continuing to stir to obtain a first solution; using a mixed aqueous solution of aluminum nitrate nonahydrate and cobalt nitrate hexahydrate to adjust the pH value of the first solution to a first value, heating to a second temperature and stirring to react, generating a melamine formaldehyde resin-coated ammonium polyphosphate AMF and a metal ion salt mixed solution; adding chloroformic acid emulsion VC to the mixed solution of AMF and metal ion salts to stir and react to generate a mixed solution, using a sodium carbonate solution to adjust the pH value of the mixed solution to a second value and continue to stir and react to obtain a second solution; filtering and drying the second solution to generate an AMF / VC / LDHs composite coated flame retardant. The present disclosure can improve preparation efficiency.

Description

Technical Field

[0001] The embodiments of the present disclosure relate to the technical field of flame retardants and fire retardant coatings, and in particular, to a preparation method of a composite coated flame retardant and the composite coated flame retardant. Background Art

[0002] In order to improve the safety performance of battery packs and energy storage systems, coating the external and internal components of the battery pack with intumescent fire retardant coatings has become an effective means.

[0003] Ammonium polyphosphate (APP) is a key component of intumescent fire retardant coatings. It produces acidic substances such as phosphoric acid and polyphosphoric acid at high temperatures, which can undergo esterification reaction with carbonizing agents to form a carbon layer. However, APP has poor water resistance and compatibility with the coating matrix.

[0004] In the related art, melamine formaldehyde resin can be used to coat ammonium polyphosphate to obtain AMF to solve the above technical problems. In the coating process, an additional acid source is usually required to promote the condensation of hydroxymethyl melamine to form a resin. The layered double hydroxide prepared with a mixed solution of metal ion salts as raw materials will decompose at high temperatures to form water and absorb a large amount of heat. Therefore, it is often used in combination with AMF to play a role in flame retardancy and smoke suppression.

[0005] In the above flame retardant system, the synthesis of AMF and the synthesis of layered double hydroxides (LDHs) are two independent processes, which increases the complexity of the fire retardant coating process and causes waste of raw materials. In addition, adding AMF and LDHs separately to the coating is prone to problems with dispersion uniformity, making it difficult for the two to achieve a synergistic flame retardant effect, affecting the expansion and thermal insulation properties of the coating. Summary of the invention

[0006] The purpose of the present disclosure is to provide a preparation method of a composite coated flame retardant and a composite coated flame retardant, thereby overcoming the problem of complex fire retardant coating process caused by the limitations and defects of related technologies at least to a certain extent.

[0007] According to one aspect of the present disclosure, a method for preparing a composite coated flame retardant is provided, comprising: dissolving ammonium polyphosphate in an ethanol aqueous solution and stirring at a first temperature, and adding a hydroxymethyl melamine solution and continuing to stir to obtain a first solution; adjusting the pH value of the first solution to a first value using a mixed aqueous solution of aluminum nitrate nonahydrate and cobalt nitrate hexahydrate, heating the solution to a second temperature and stirring the solution to generate a mixed solution of ammonium polyphosphate AMF coated with a melamine formaldehyde resin and a metal ion salt; adding chloroformic acid emulsion VC to the mixed solution of AMF and the metal ion salt and stirring the solution to generate a mixed solution, adjusting the pH value of the mixed solution to a second value using a sodium carbonate solution and continuing to stir the solution to obtain a second solution; filtering and drying the second solution to generate an AMF / VC / LDHs composite coated flame retardant.

[0008] In an exemplary embodiment of the present disclosure, the degree of polymerization of the ammonium polyphosphate is not less than 1000, and the weight ratio of the ammonium polyphosphate to the hydroxymethyl melamine solution is 1:1.6-1.8.

[0009] In an exemplary embodiment of the present disclosure, the concentration of the methylol melamine solution is 0.029-0.033 mol / L.

[0010] In an exemplary embodiment of the present disclosure, the volume ratio of ethanol to water in the ethanol aqueous solution is 1:1.

[0011] In an exemplary embodiment of the present disclosure, the molar ratio of the aluminum nitrate nonahydrate to the cobalt nitrate hexahydrate in the mixed aqueous solution is 1:2-4.

[0012] In an exemplary embodiment of the present disclosure, the solid content of the chloroemulsion VC is 46% to 50%, the pH value of the chloroemulsion VC is 5.5 to 6.5, and the addition amount of the chloroemulsion VC is 2 to 2.2 times the weight of the ammonium polyphosphate.

[0013] In an exemplary embodiment of the present disclosure, the concentration of the sodium carbonate solution is 0.3-0.4 mol / L.

[0014] In an exemplary embodiment of the present disclosure, the first value is smaller than the second value, the first value is 5-5.5, and the second value is 7-8.

[0015] In an exemplary embodiment of the present disclosure, the first temperature is 50°C to 60°C, and the second temperature is 70°C to 80°C.

[0016] According to one aspect of the present disclosure, a composite coated flame retardant is provided, wherein the composite coated flame retardant is prepared according to any one of the above-mentioned methods for preparing the composite coated flame retardant.

[0017] In the technical solution provided in the embodiments of the present disclosure, on the one hand, a mixed metal salt solution is used as an acid source for synthesizing AMF without introducing an additional acid source, and at the same time as a metal ion source for synthesizing layered double hydroxides LHDs, and a chlorine partial emulsion is selected as a bridging agent and by strictly controlling the synthesis conditions such as the pH value, an AMF / VC / LDHs composite coated flame retardant is directly prepared through a one-time process, without the need to independently synthesize AMF and layered double hydroxides through different processes, thereby simplifying the preparation process and reducing the process complexity. On the other hand, the waste of raw materials is avoided, and production time and cost are saved. On the other hand, before adding APP and LDHs to the coating, they are first coated and anchored with each other to form a composite coated flame retardant, which is more conducive to improving the dispersion stability of the two substances in the coating, so that the two can work together, thereby giving the coating a better expansion and heat insulation effect.

[0018] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings herein are incorporated into the specification and constitute a part of the specification, illustrate embodiments consistent with the present disclosure, and together with the specification are used to explain the principles of the present disclosure. Obviously, the accompanying drawings described below are only some embodiments of the present disclosure, and for ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without creative work.

[0020] Figure 1 The flowchart schematically shows a method for preparing a composite coated flame retardant in an embodiment of the present disclosure.

[0021] Figure 2 A schematic diagram of a fire retardant coating made from uncoated APP and LDHs is shown schematically.

[0022] Figure 3 A schematic diagram of a fire retardant coating made from uncoated APP is shown schematically.

[0023] Figure 4 A schematic diagram of a fire retardant coating made of the flame retardant prepared according to Example 1 is schematically shown.

[0024] Figure 5 A schematic diagram of a fire retardant coating made of the flame retardant prepared according to Example 2 is schematically shown.

[0025] Figure 6 A schematic diagram of a fire retardant coating made of the flame retardant prepared according to Example 3 is schematically shown.

[0026] Figure 7 A schematic diagram of a fire retardant coating made of the flame retardant prepared according to Example 4 is schematically shown.

[0027] Figure 8 A schematic diagram of a fire retardant coating made of the flame retardant prepared according to Example 5 is schematically shown. DETAILED DESCRIPTION

[0028] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as being limited to the examples set forth herein; on the contrary, these embodiments are provided so that the present disclosure will be more comprehensive and complete, and the concepts of the example embodiments are fully conveyed to those skilled in the art. The described features, structures, or characteristics may be combined in one or more embodiments in any suitable manner. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present disclosure. However, those skilled in the art will appreciate that the technical solutions of the present disclosure may be practiced while omitting one or more of the specific details, or other methods, components, devices, steps, etc. may be adopted. In other cases, known technical solutions are not shown or described in detail to avoid obscuring various aspects of the present disclosure.

[0029] The terms "a", "an", "the" and "said" used in this specification are used to indicate the presence of one or more elements / components, etc.; the terms "including" and "having" are used to express an open-ended inclusion and mean that there may be additional elements / components, etc. in addition to the listed elements / components, etc.; the terms "first" and "second" etc. are used only as labels and are not intended to limit the quantity of their objects.

[0030] With the increasing popularity of new energy vehicles, people are paying more and more attention to the safety and fire resistance of vehicles. The power battery system of new energy vehicles, especially electric vehicles, may experience thermal runaway under high temperature or short circuit conditions, which may cause fire or explosion. In order to improve the safety performance of battery packs and energy storage systems, coating the external and internal components of battery packs with intumescent fire retardant coatings has become an effective means. When this coating encounters high temperatures, it will expand rapidly to form a heat-insulating protective layer that effectively blocks the transfer of heat, thereby significantly improving the fire resistance of the battery pack under high temperature and fire conditions and reducing the risk of fire.

[0031] Ammonium polyphosphate (APP) is a key component of intumescent fire retardant coatings. It produces acidic substances such as phosphoric acid and polyphosphoric acid at high temperatures, which can undergo esterification reaction with carbon forming agents to form a carbon layer. However, APP has poor water resistance and compatibility with coating matrix, which seriously restricts its widespread application in intumescent fire retardant coatings.

[0032] Using melamine formaldehyde resin to coat ammonium polyphosphate to obtain AMF is an important method to solve the above problems. However, the coating process usually requires the introduction of an additional acid source to promote the condensation of hydroxymethyl melamine to form a resin. Layered double hydroxides (LDHs) will decompose at high temperatures to form water and absorb a large amount of heat. Therefore, they are often used in combination with AMF in fire retardant coatings to play a role in flame retardancy and smoke suppression.

[0033] In the flame retardant system of the related technology, the synthesis of AMF and the synthesis of layered double hydroxide are two independent processes. LDHs does not have a coating effect on APP. The addition of both to the fire retardant coating is just a simple doping behavior, which not only increases the complexity of the fire retardant coating process, but also produces some unnecessary waste of raw materials.

[0034] In order to solve the above technical problems, the present disclosure provides a method for preparing a composite coated flame retardant for use in a battery pack and an energy storage system or other systems. Figure 1 As shown in, the preparation method of the composite coated flame retardant mainly includes the following steps:

[0035] In step S110, ammonium polyphosphate is dissolved in an ethanol aqueous solution and stirred at a first temperature, and a hydroxymethyl melamine solution is added and stirred continuously to obtain a first solution;

[0036] In step S120, the pH value of the first solution is adjusted to a first value using a mixed aqueous solution of aluminum nitrate nonahydrate and cobalt nitrate hexahydrate, the temperature is raised to a second temperature and stirred for reaction to generate a mixed solution of melamine formaldehyde resin-coated ammonium polyphosphate AMF and metal ion salt;

[0037] In step S130, chloroform emulsion VC is added to the mixed solution of AMF and metal ion salt to react with stirring to generate a mixed solution, and the pH value of the mixed solution is adjusted to a second value with sodium carbonate solution and the stirring reaction is continued to obtain a second solution;

[0038] In step S140, the second solution is filtered and dried to generate an AMF / VC / LDHs composite coated flame retardant.

[0039] Next, the preparation method of the composite coated flame retardant in the embodiment of the present disclosure is specifically described.

[0040] In step S110, ammonium polyphosphate is dissolved in an ethanol aqueous solution and stirred at a first temperature, and a hydroxymethyl melamine solution is added and stirred continuously to obtain a first solution.

[0041] In the disclosed embodiment, ammonium polyphosphate can be dissolved in an ethanol aqueous solution and stirred at a first temperature. Wherein, the degree of polymerization n of ammonium polyphosphate is not less than 1000, that is, the degree of polymerization n of ammonium polyphosphate is greater than or equal to 1000. The volume ratio of ethanol to water in the ethanol aqueous solution is 1:1. The first temperature can be 60°C, or 50°C or other temperatures, which is determined according to actual needs, as long as the ammonium polyphosphate can be fully dissolved. The stirring time at the first temperature can be 30 minutes, 40 minutes or any suitable time, which is not specifically limited here.

[0042] Further, a methylol melamine solution may be added and stirred continuously to obtain a first solution. The concentration of the methylol melamine solution is 0.029-0.033 mol / L. The weight ratio of ammonium polyphosphate to the methylol melamine solution is 1:1.6-1.8. The stirring time for adding the methylol melamine solution and stirring continuously may be 30 minutes, or other suitable time. Based on this, the first solution may be obtained by mixing ammonium polyphosphate, ethanol aqueous solution, and methylol melamine solution.

[0043] In step S120, the pH value of the first solution is adjusted to a first value using a mixed aqueous solution of aluminum nitrate nonahydrate and cobalt nitrate hexahydrate, and the temperature is raised to a second temperature and stirred for reaction to generate a mixed solution of melamine formaldehyde resin-coated ammonium polyphosphate AMF and metal ion salt.

[0044] In the embodiment of the present disclosure, the mixed aqueous solution of aluminum nitrate nonahydrate and cobalt nitrate hexahydrate can adjust the pH value of the first solution. The molar ratio of aluminum nitrate nonahydrate to cobalt nitrate hexahydrate is 1:2~4. The mixed aqueous solution of aluminum nitrate nonahydrate and cobalt nitrate hexahydrate can adjust the pH value of the first solution to a first value, and the first value can be 5~5.5.

[0045] After the pH value of the first solution is adjusted to the first value, the temperature can be raised to the second temperature, and the stirring reaction can be carried out at the second temperature. The second temperature can be higher than the first temperature, for example, the second temperature can be 80°C, or 70°C, as long as a mixed solution of melamine formaldehyde resin-coated ammonium polyphosphate AMF and metal ion salt can be obtained, which is determined according to actual needs. The time of stirring reaction at the second temperature can be greater than the stirring time at the first temperature, for example, the time of stirring reaction at the second temperature can be 2 to 2.5 hours. Among them, the mixed solution of melamine formaldehyde resin-coated ammonium polyphosphate AMF and metal ion salt refers to a mixed solution of AMF and metal ion salt. AMF refers to melamine formaldehyde resin-coated APP, which can be obtained by coating ammonium polyphosphate with melamine formaldehyde resin.

[0046] Next, in step S130, chloroform emulsion VC is added to the mixed solution of AMF and metal ion salt to react with stirring to generate a mixed solution, and the pH value of the mixed solution is adjusted to a second value with sodium carbonate solution and the stirring reaction is continued to obtain a second solution.

[0047] In the disclosed embodiment, chloroformic acid emulsion VC can be added to the mixed solution of melamine formaldehyde resin coated ammonium polyphosphate AMF and metal ion salt and stirred for reaction, and the stirring reaction time can be 1.5 to 2 hours. Further, after the reaction is completed, the pH value of the mixed solution can be adjusted to a second value using sodium carbonate solution and the stirring reaction can be continued. The second value can be greater than the first value, and the second value can be, for example, 7 to 8. After the pH value of the mixed solution is adjusted to the second value, the stirring reaction can also be continued at a second temperature to obtain a second solution, and the stirring reaction time can be 3 to 4 hours.

[0048] The solid content of the chloro-emulsion is 46% to 50%, the pH value of the chloro-emulsion is 5.5 to 6.5, and the amount of the chloro-emulsion added is 2 to 2.2 times the weight of the ammonium polyphosphate. The concentration of the sodium carbonate solution is 0.3 to 0.4 mol / L, and the sodium carbonate solution is used to adjust the pH value of the mixed solution to the second value.

[0049] Continue to refer Figure 1 As shown in , in step S140, the second solution is filtered and dried to generate an AMF / VC / LDHs composite coated flame retardant.

[0050] In the disclosed embodiment, the second solution can be filtered, washed, and dried after washing. The drying temperature and drying time can be determined according to actual needs. For example, the drying temperature can be 60°C or other suitable temperatures, and the drying time can be 1 hour or other suitable times, which are not specifically limited here. After filtering and drying, an AMF / VC / LDHs composite coated flame retardant can be generated.

[0051] Next, the preparation method of the composite coated flame retardant provided by the present disclosure is described in detail with reference to the examples.

[0052] In some embodiments, a fire retardant coating made of uncoated APP and LDHs can be used. When the fire retardant coating is made of uncoated APP and LDHs, the mass ratio of APP to LDHs is 1:1. In other embodiments, the fire retardant coating can also be made of uncoated APP.

[0053] In the embodiment of the present disclosure, in the process of preparing the composite coated flame retardant, the weight and concentration of the hydroxymethyl melamine solution, the molar ratio of aluminum nitrate nonahydrate and cobalt nitrate hexahydrate, the time of stirring reaction at the second temperature, the weight of the chloroformic emulsion of the mixed solution of ammonium polyphosphate AMF coated with melamine formaldehyde resin and metal ion salt, the concentration of the sodium carbonate solution, and one or more of the second value can be adjusted.

[0054] Example 1

[0055] The preparation method of the composite coated flame retardant mainly includes the following steps:

[0056] Step 1: Dissolve 4 g of ammonium polyphosphate in 15 mL of ethanol aqueous solution, stir at a first temperature of 60°C for 30 min, then add 6.5 g of hydroxymethyl melamine solution, the concentration of which is 0.029 mol / L, continue stirring for 30 min, and the resulting mixed solution is marked as the first solution. The volume ratio of ethanol to water in the ethanol aqueous solution is 1:1.

[0057] Step 2: titrate the pH value of the first solution to a first value of 5-5.5 using a mixed aqueous solution of aluminum nitrate nonahydrate and cobalt nitrate hexahydrate in a molar ratio of 1:2, raise the temperature to a second temperature of 80° C., stir and react for 2.5 hours, and obtain a mixed solution of AMF and metal ion salt.

[0058] Step 3: Add 8g of chloroformic acid emulsion to the mixed solution of melamine formaldehyde resin coated ammonium polyphosphate AMF and metal ion salt, and continue stirring for 1.5 hours to generate a mixed solution. After the reaction is completed, use a sodium carbonate solution with a concentration of 0.4 mol / L to titrate the pH value of the mixed solution to 7.5-8, and continue stirring and reacting at a second temperature of 80°C for 3 hours to determine the second solution.

[0059] Step 4: Filter, wash and dry the obtained second solution to finally obtain the AMF / VC / LDHs composite coated flame retardant.

[0060] Example 2

[0061] Step 1: Dissolve 4 g of ammonium polyphosphate in 15 mL of ethanol aqueous solution, stir for 30 min at a first temperature of 60°C, then add 6.8 g of hydroxymethyl melamine solution, the concentration of which is 0.030 mol / L, continue stirring for 30 min, and the resulting mixed solution is marked as the first solution. The volume ratio of ethanol to water in the ethanol aqueous solution is 1:1.

[0062] Step 2: titrate the pH value of the first solution to a first value of 5-5.5 using a mixed aqueous solution of aluminum nitrate nonahydrate and cobalt nitrate hexahydrate in a molar ratio of 1:3, raise the temperature to a second temperature of 80° C., stir and react for 2 hours, and obtain a mixed solution of AMF and metal ion salt.

[0063] Step 3: Add 8.4 g of chloroformic acid emulsion to the mixed solution of melamine formaldehyde resin coated ammonium polyphosphate AMF and metal ion salt, and continue stirring for 2 hours to generate a mixed solution. After the reaction is completed, the pH value of the mixed solution is titrated to a second value of 7 to 7.5 using a sodium carbonate solution with a concentration of 0.3 mol / L, and the reaction is continued to stir at a second temperature of 80° C. for 3.5 hours to generate a second solution.

[0064] Step 4: Filter, wash and dry the obtained second solution to finally obtain the AMF / VC / LDHs composite coated flame retardant.

[0065] Example 3

[0066] Step 1: Dissolve 4 g of ammonium polyphosphate in 15 mL of ethanol aqueous solution, stir at a first temperature of 60°C for 30 min, then add 7.2 g of hydroxymethyl melamine solution, the concentration of which is 0.031 mol / L, continue stirring for 30 min, and the resulting mixed solution is marked as the first solution. The volume ratio of ethanol to water in the ethanol aqueous solution is 1:1.

[0067] Step 2: titrate the pH value of the first solution to 5-5.5 using a mixed aqueous solution of aluminum nitrate nonahydrate and cobalt nitrate hexahydrate in a molar ratio of 1:4, raise the temperature to a second temperature of 80° C., stir and react for 2.5 hours, and obtain a mixed solution of AMF and metal ion salt.

[0068] Step 3: Add 8.8g of chloroformic acid emulsion to the mixed solution of melamine formaldehyde resin coated ammonium polyphosphate AMF and metal ion salt, and continue stirring for 1.5 hours to generate a mixed solution. After the reaction is completed, use a 0.4 mol / L sodium carbonate solution to titrate the pH value of the mixed solution to 7.5-8, and continue stirring the reaction at a second temperature of 80°C for 4 hours to determine the second solution.

[0069] Step 4: Filter, wash and dry the obtained second solution to finally obtain the AMF / VC / LDHs composite coated flame retardant.

[0070] Example 4

[0071] Step 1: Dissolve 4 g of ammonium polyphosphate in 15 mL of ethanol aqueous solution, stir for 30 min at a first temperature of 60°C, then add 6.5 g of hydroxymethyl melamine solution, the concentration of which is 0.032 mol / L, continue stirring for 30 min, and the resulting mixed solution is marked as the first solution. The volume ratio of ethanol to water in the ethanol aqueous solution is 1:1.

[0072] Step 2: titrate the pH value of the first solution to 5-5.5 using a mixed aqueous solution of aluminum nitrate nonahydrate and cobalt nitrate hexahydrate in a molar ratio of 1:2, raise the temperature to a second temperature of 80° C., stir and react for 2 hours, and obtain a mixed solution of AMF and metal ion salt.

[0073] Step 3: Add 8 g of chloroformic acid emulsion to the mixed solution of melamine formaldehyde resin coated ammonium polyphosphate AMF and metal ion salt, and continue stirring for 2 hours to generate a mixed solution. After the reaction is completed, the pH value of the mixed solution is titrated to 7-7.5 using a sodium carbonate solution with a concentration of 0.3 mol / L, and the reaction is continued at a second temperature of 80°C for 3 hours to obtain a second solution.

[0074] Step 4: Filter, wash and dry the obtained second solution to finally obtain a composite coated flame retardant. The composite coated flame retardant may be an AMF / VC / LDHs composite coated flame retardant.

[0075] Example 5

[0076] Step 1, dissolve 4g of ammonium polyphosphate in 15mL of ethanol aqueous solution, stir for 30min at a first temperature of 60°C, then add 6.8g of hydroxymethyl melamine solution, the concentration of the hydroxymethyl melamine solution can be 0.033 mol / L, continue stirring for 30min, and the resulting mixed solution is marked as the first solution; wherein the volume ratio of ethanol to water in the ethanol aqueous solution is 1:1.

[0077] Step 2: titrate the pH value of the first solution to 5-5.5 using a mixed aqueous solution of aluminum nitrate nonahydrate and cobalt nitrate hexahydrate in a molar ratio of 1:3, raise the temperature to a second temperature of 80° C., stir and react for 2.5 hours, and obtain a mixed solution of AMF and metal ion salt.

[0078] Step 3: Add 8.4 g of chloroformic acid emulsion to the mixed solution of melamine formaldehyde resin coated ammonium polyphosphate AMF and metal ion salt, and continue stirring for 1.5 hours to generate a mixed solution. After the reaction is completed, the pH value of the mixed solution is titrated to 7.5-8 using a sodium carbonate solution with a concentration of 0.4 mol / L, and the reaction is continued at a second temperature of 80°C for 3.5 hours to obtain a second solution.

[0079] Step 4: Filter, wash and dry the obtained second solution to finally obtain the AMF / VC / LDHs composite coated flame retardant.

[0080] After preparing the AMF / VC / LDHs composite coated flame retardant, a fire retardant coating can be made according to the prepared AMF / VC / LDHs composite coated flame retardant. Exemplarily, in the process of making a fire retardant coating according to the prepared AMF / VC / LDHs composite coated flame retardant, acrylic emulsion, AMF / VC / LDHs composite coated flame retardant, melamine, pentaerythritol, titanium dioxide, water and additives can be included. In some embodiments, 5 parts of water are added to 25 parts of acrylic emulsion and stirred at a speed of 1000r / min for 10 minutes. The speed is increased to 1500r / min, and 22 parts of the composite coated flame retardant prepared according to Examples 1 to 5, 12 parts of melamine, 12 parts of pentaerythritol and 4 parts of titanium dioxide are added in sequence, and stirred for 30 minutes. Then 0.4 parts of defoamer BYK022 are added, and stirring is continued for 10 minutes to obtain a fire retardant coating.

[0081] Furthermore, the prepared fire retardant coating can be tested for expansion performance. For example, the prepared fire retardant coating is applied to a carbon steel surface and cured at room temperature for 24 hours, and the dry film thickness is 1.7±0.2 mm. The fire retardant coating is continuously heated for 4 minutes using a flame gun with a flame temperature of about 1300°C to observe the expansion effect.

[0082] In addition, fire retardant coatings can also be prepared based on flame retardants made from uncoated APP and LDHs. For example, 5 parts of water are added to 25 parts of acrylic emulsion and stirred at a speed of 1000r / min for 10 minutes. The speed is increased to 1500r / min, and 22 parts of flame retardant, 12 parts of melamine, 12 parts of pentaerythritol and 4 parts of titanium dioxide are added in sequence and stirred for 30 minutes. Then 0.4 parts of defoamer BYK022 are added and stirred for 10 minutes to obtain a fire retardant coating.

[0083] Figure 2 The fire retardant coating made of the flame retardant prepared from the uncoated APP and LDHs is shown in FIG. Figure 3 The fire retardant coating made of the flame retardant prepared according to APP is shown in FIG.

[0084] Figures 4 to 8 The fire retardant coatings are made of composite coated flame retardants prepared according to Examples 1 to 5. Figures 4 to 8 The fire retardant coating prepared according to Example 1 to Example 5 and Figure 2 , Figure 3 By comparing with the fire-retardant coating in the examples, it can be seen that the fire-retardant coating made of the composite coated flame retardant prepared according to Examples 1 to 5 forms a higher and denser expanded carbon layer when exposed to fire, and the AMF / VC / LDHs composite coated flame retardant prepared according to the preparation method in the embodiments of the present invention has a good expansion and heat insulation effect.

[0085] In summary, in the embodiments of the present disclosure, a mixed metal salt solution is used as an acid source for synthesizing AMF without introducing an additional acid source, and at the same time as a metal ion source for synthesizing LDHs. Chlorine partial emulsion is selected as a bridging agent and by strictly controlling the synthesis conditions, an AMF / VC / LDHs composite coated flame retardant is directly prepared through a one-time process, which simplifies the preparation process, reduces complexity, and improves preparation efficiency. The waste of raw materials is avoided, and production time and cost are saved. Before adding APP and LDHs to the coating, they are first coated and anchored with each other to prepare a composite coated flame retardant, which is more conducive to improving the dispersion stability of the two substances in the coating, so that the two can work together, thereby giving the coating a better expansion and heat insulation effect.

[0086] In the embodiment of the present disclosure, a composite coated flame retardant is also provided. The composite coated flame retardant is an AMF / VC / LDHs composite coated flame retardant, which can be prepared according to the method of step S110 to step S140.

[0087] In the embodiments of the present disclosure, a mixed metal salt solution is used as an acid source for synthesizing AMF without introducing an additional acid source, and at the same time as a metal ion source for synthesizing LDHs. A chloro-eluting emulsion is selected as a bridging agent and the pH value of the mixed solution is adjusted to strictly control the synthesis conditions. The AMF / VC / LDHs composite coated flame retardant is directly prepared in one go through a "one-pot" process, which simplifies the preparation process of the flame retardant, reduces the process complexity, and improves the preparation efficiency. Before adding APP and LDHs to the coating, they are first coated and anchored with each other to prepare a composite coated flame retardant, which is more conducive to improving the dispersion stability of the two substances in the coating, so that the two can work synergistically, thereby giving the coating a better expansion and heat insulation effect. The composite coated flame retardant prepared in the embodiments of the present disclosure is used to give the fire retardant coating excellent flame retardant and heat insulation properties.

[0088] In addition, the above-mentioned figures are only schematic illustrations of the processes included in the method according to the exemplary embodiments of the present disclosure, and are not intended to be limiting. It is easy to understand that the processes shown in the above-mentioned figures do not indicate or limit the time sequence of these processes. In addition, it is also easy to understand that these processes can be performed synchronously or asynchronously, for example, in multiple modules.

[0089] Those skilled in the art will readily appreciate other embodiments of the present disclosure after considering the specification and practicing the invention disclosed herein. This application is intended to cover any modification, use or adaptation of the present disclosure, which follows the general principles of the present disclosure and includes common knowledge or customary techniques in the art that are not disclosed in the present disclosure. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present disclosure are indicated by the appended claims.

[0090] It should be understood that the present disclosure is not limited to the exact structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims.

Claims

1. A method for preparing a composite coated flame retardant, characterized in that: include: Dissolving ammonium polyphosphate in an ethanol aqueous solution and stirring at a first temperature, and adding a hydroxymethyl melamine solution and continuing to stir to obtain a first solution; The pH value of the first solution is adjusted to a first value using a mixed aqueous solution of aluminum nitrate nonahydrate and cobalt nitrate hexahydrate, and the temperature is raised to a second temperature and stirred for reaction to generate a mixed solution of melamine formaldehyde resin-coated ammonium polyphosphate AMF and a metal ion salt; Adding chloro-emulsion VC to a mixed solution of AMF and metal ion salt to react with stirring to generate a mixed solution, adjusting the pH value of the mixed solution to a second value using a sodium carbonate solution and continuing the stirring reaction to obtain a second solution; the solid content of the chloro-emulsion VC is 46% to 50%, the pH value of the chloro-emulsion VC is 5.5 to 6.5, and the amount of the chloro-emulsion VC added is 2 to 2.2 times the weight of the ammonium polyphosphate; the first value is less than the second value, the first value is 5 to 5.5, and the second value is 7 to 8; The second solution is filtered and dried to generate an AMF / VC / LDHs composite coated flame retardant.

2. The method for preparing the composite coated flame retardant according to claim 1, characterized in that: The degree of polymerization of the ammonium polyphosphate is not less than 1000, and the weight ratio of the ammonium polyphosphate to the hydroxymethyl melamine solution is 1:1.6-1.

8.

3. The method for preparing the composite coated flame retardant according to claim 1, characterized in that: The concentration of the hydroxymethyl melamine solution is 0.029-0.033 mol / L.

4. The method for preparing the composite coated flame retardant according to claim 1, characterized in that: The volume ratio of ethanol to water in the ethanol aqueous solution is 1:

1.

5. The method for preparing the composite coated flame retardant according to claim 1, characterized in that: The molar ratio of the aluminum nitrate nonahydrate to the cobalt nitrate hexahydrate in the mixed aqueous solution is 1:2-4.

6. The method for preparing the composite coated flame retardant according to claim 1, characterized in that: The concentration of the sodium carbonate solution is 0.3-0.4 mol / L.

7. The method for preparing the composite coated flame retardant according to claim 1, characterized in that: The first temperature is 50°C to 60°C, and the second temperature is 70°C to 80°C.

8. A composite coated flame retardant, characterized in that: The composite coated flame retardant is prepared according to the preparation method of the composite coated flame retardant according to any one of claims 1 to 7.

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