A film forming method of a coating with waterproof and fireproof performance

Abstract

The present application relates to the field of coating chemical industry and special functional coating film forming process, specifically to a film forming method of coating with waterproof and fireproof performance; preparation of multifunctional reactive modifier, preparation of two-component coating composition and film forming and other steps; the method combines hydroxyl-containing water-based matrix resin and water-dispersed inorganic nanoparticles, the core is to form a silicon-oxygen-silicon crosslinking network through the dehydration condensation of silanol groups in the modifier and hydroxyl groups in the system, and promote the migration of fluorine-containing segments to the interface to form a gradient distribution; the present application solves the defects that the flame retardant is easy to aggregate and settle and easily damages the compactness of the coating film in the traditional physical blending method, uses in-situ reaction to anchor the waterproof and flame-retardant functional groups in the interpenetrating network coating film in the form of covalent bond, effectively blocks the penetration of water and limits the migration of flame-retardant components, and realizes the stable consideration of excellent fireproof performance and water erosion resistance of the coating.

Description

Technical Field

[0001] This invention relates to the field of coatings and chemicals and special functional coating film-forming processes, specifically a film-forming method for a coating that combines waterproof and fireproof properties. Background Technology

[0002] In the fields of modern architecture, new energy battery casings, and special equipment protection, coating materials often need to possess both excellent waterproof and fireproof properties. However, in traditional coating systems, these two properties are mutually restrictive: conventional intumescent fire-retardant coatings have high hydrophilicity, and under long-term high humidity or water erosion environments, the flame-retardant components are prone to dissolution and leaching, resulting in a significant decrease in fireproof performance; while conventional waterproof coatings, although having low surface energy and excellent water resistance, are inherently flammable or have extremely low flame-retardant efficiency.

[0003] Currently, physical blending is commonly used in industry, where flame-retardant powder is directly dispersed in a waterproof resin matrix. However, this method has technical drawbacks: when the amount of flame retardant added is large, it has poor compatibility with the matrix resin, easily leading to agglomeration and sedimentation; the introduction of powder can damage the density of the waterproof coating, increasing the penetration path of water molecules; physical encapsulation cannot restrict the molecular movement of the flame retardant, and the flame-retardant components will still migrate and be removed during long-term service. Therefore, there is a need in this field to provide a film-forming method for coatings that uses in-situ reactions to fix waterproof and fire-retardant functional groups in the form of covalent bonds in an interpenetrating network coating, thus resolving the contradiction between water resistance and fire resistance. Summary of the Invention

[0004] The purpose of this invention is to provide a film-forming method for a coating that combines waterproof and fireproof properties. This addresses the problems in existing technologies where physically blended flame retardants tend to agglomerate and settle, compromising the density of the coating film, and that flame-retardant components easily migrate and are removed under long-term service or water erosion, making it difficult to simultaneously achieve both waterproof and fireproof performance. Specifically, the technical solution of this invention is as follows:

[0005] A method for forming a film of a coating that combines waterproof and fireproof properties, characterized by comprising the following steps:

[0006] Step 1, Preparation of the multifunctional reactive modifier: Hexachlorocyclotriphosphazene, 10-(2,5-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, perfluorohexylethanol and 3-aminopropyltriethoxysilane are reacted to prepare the multifunctional reactive modifier.

[0007] Step 2, Preparation of the two-component coating composition: Hydroxyl-containing aqueous matrix resin and water-dispersible inorganic nanoparticles are mixed evenly to obtain component A; the multifunctional reactive modifier prepared in step 1 is used as component B; component A and component B are mixed and dispersed at an effective component mass ratio of 100:15 to 100:30 to obtain a coating dispersion; the mass of the effective component refers to the sum of the mass of the solid resin portion of the aqueous matrix resin and the solid particle portion of the water-dispersible inorganic nanoparticles in component A, and the pure substance mass of the multifunctional reactive modifier in component B.

[0008] Step 3, film formation: The coating dispersion is coated onto the surface of the substrate, dried to allow the moisture and solvent to evaporate, and then heated to cure, forming an interpenetrating network coating film on the surface of the substrate.

[0009] Preferably, the preparation of the multifunctional reactive modifier in step one specifically includes the following steps:

[0010] (1) Under inert gas protection, hexachlorocyclotriphosphazene was dissolved in anhydrous tetrahydrofuran, and triethylamine was added to obtain a first solution; 10-(2,5-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide was dissolved in anhydrous tetrahydrofuran to obtain a second solution; the second solution was added dropwise to the first solution for reflux reaction, cooled and filtered to obtain intermediate A solution;

[0011] (2) Add perfluorohexylethanol and anhydrous potassium carbonate to the intermediate A solution and react. After cooling, filter to obtain intermediate B solution.

[0012] (3) Cool the intermediate B solution to an ice-water bath, add triethylamine as an acid-binding agent, add 3-aminopropyltriethoxysilane dropwise, and after the addition is complete, restore the room temperature to carry out the reaction. After the reaction is completed, filter the solution and remove the solvent by rotary evaporation under reduced pressure to obtain the multifunctional reactive modifier.

[0013] Preferably, in the film-forming method of the waterproof and fireproof coating according to claim 1, in step one:

[0014] The molar ratio of the hexachlorocyclotriphosphazene to the 10-(2,5-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is 1:2.

[0015] The reflux reaction conditions described in step one (1) are to raise the temperature to 65°C and carry it out for 12 hours;

[0016] The reaction conditions described in step one (2) are to raise the temperature to 65°C and carry out the reaction for 10 hours;

[0017] The temperature of the ice-water bath described in step one (3) is 0°C to 5°C. After the addition is completed, the temperature is restored to 25°C and the reaction is carried out for 6 hours.

[0018] Preferably, in step two, the hydroxyl-containing aqueous matrix resin is an aqueous hydroxyl acrylic resin or an aqueous polyurethane dispersion.

[0019] Preferably, the water-dispersible inorganic nanoparticles are water-dispersible nano-silica.

[0020] Preferably, in step three, the coating dispersion is applied to the substrate surface by spraying or roller coating.

[0021] Preferably, in step three, the fluorine element in the interpenetrating network coating formed after curing decreases from the outer surface to the interior along the thickness direction of the interpenetrating network coating.

[0022] Preferably, in step two, the dispersion conditions are shear dispersion at 25°C and a rotation speed of 1500 rpm.

[0023] Preferably, in step three: the treatment to evaporate moisture and solvent specifically involves treating at 25°C to 40°C for 15 to 30 minutes to evaporate moisture and solvent; the curing specifically involves heating to 80°C to 120°C for curing for 30 to 60 minutes.

[0024] The beneficial effects of this invention are as follows:

[0025] This invention utilizes the silanol groups generated by the hydrolysis of triethoxysilyl groups in a multifunctional reactive modifier to undergo a dehydration condensation reaction with the side chain hydroxyl groups of a hydroxyl-containing aqueous matrix resin and the surface hydroxyl groups of water-dispersible inorganic nanoparticles, forming a siloxane crosslinked network during curing. This reaction mechanism combines waterproof and flame-retardant components in an interpenetrating network coating, effectively overcoming the problems of easy agglomeration and sedimentation of flame retardants in traditional physical blending methods, and limiting the migration and removal of flame-retardant components in long-term high humidity or water erosion environments.

[0026] During the moisture and solvent evaporation stage of the coating film, this invention promotes the spontaneous migration of fluorinated segments introduced by perfluorohexyl ethanol in the multifunctional reactive modifier to the interface between the coating and the air. This results in a decreasing distribution of fluorine elements in the cured interpenetrating network coating film from the outer surface to the interior along the thickness direction. This gradient distribution structure effectively blocks the penetration path of water molecules, improving waterproof performance while maintaining the compactness and long-term stability of the overall internal structure of the coating film.

[0027] This invention utilizes the reaction of hexachlorocyclotriphosphazene with 10-(2,5-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and combines it with water-dispersible inorganic nanoparticles. The interpenetrating network coating formed by high-temperature curing and cross-linking enhances the protective strength of the substrate surface, effectively solving the defect of conventional intumescent fire retardant coatings that easily dissolve and leach flame retardant components due to their strong hydrophilicity. This achieves a stable balance between excellent fire resistance and water erosion resistance of the coating. Detailed Implementation

[0028] The technical solutions in the embodiments of the present invention will be clearly and completely described below; the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0029] Example 1:

[0030] This embodiment provides a film-forming method for a coating that combines waterproof and fireproof properties, specifically including the following steps:

[0031] In S1, the preparation of the multifunctional reactive modifier is as follows: 34.77 g (0.10 mol) of hexachlorocyclotriphosphazene is added to a four-necked flask equipped with a mechanical stirrer, thermometer and reflux condenser. Nitrogen gas is introduced for protection. 200 mL of anhydrous tetrahydrofuran is added to dissolve it completely. Then, 22.30 g (0.22 mol) of triethylamine is added to obtain the first solution.

[0032] The first solution provides a homogeneous dissolution environment for the subsequent nucleophilic substitution reaction, and the triethylamine in the system acts as an acid-binding agent to absorb the hydrogen chloride produced in the reaction, promoting the forward reaction; separately, 64.85 g of 10-(2,5-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (0.20 mol) was added to 300 mL of anhydrous tetrahydrofuran and stirred to dissolve, thus obtaining the second solution;

[0033] The second solution fully dissolves the large volume of rigid reactants, facilitating precise control of local concentrations during the dropwise addition process and thus reducing side reactions. The second solution is added dropwise to the first solution over 1 hour, with the system temperature controlled at 25°C. After the dropwise addition is complete, the temperature is raised to 65°C and refluxed for 12 hours. After cooling to room temperature, triethylamine hydrochloride is removed by filtration, and the filtrate is intermediate A solution. Intermediate A solution achieves precise substitution of some chlorine atoms on the phosphazene ring, introducing a phosphorus-containing flame-retardant framework, while retaining necessary reaction sites for subsequent hydrophobic modification.

[0034] The purity of intermediate A was determined to be 95.6% and the yield was 88.5% by high performance liquid chromatography. 72.82 g (0.20 mol) of perfluorohexylethanol and 30.40 g (0.22 mol) of anhydrous potassium carbonate were added to the intermediate A solution, and the mixture was heated to 65 °C and reacted for 10 h. After the reaction, the mixture was cooled to room temperature, and the inorganic salts were removed by filtration to obtain intermediate B solution. Intermediate B solution successfully grafted fluorinated hydrophobic segments, giving the modifier significant low surface energy characteristics, while retaining the last two active chlorine atoms for subsequent silanization crosslinking modification. The intermediate B solution was cooled to 0-5 °C (specifically 3 °C in this example), and 22.30 g (0.22 mol) of triethylamine was added under ice-water bath conditions, followed by dropwise addition of 44.27 g (0.20 mol) of 3-aminopropyltriethoxysilane, with the addition time controlled at 40 min. After the addition was completed, the temperature was restored to 25 °C, and the reaction continued for 6 h.

[0035] After the reaction was completed, the mixture was filtered, the solvent was removed under reduced pressure, and the mixture was dried under vacuum at 45°C for 8 hours to obtain a light yellow viscous multifunctional reactive modifier with a total yield of 82.4% and a high performance liquid chromatography purity of 96.2%. Infrared spectroscopy was performed on the modifier, and characteristic absorption peaks of P=N, P=O, CF and Si-OC were visible. The characteristic peak of P-Cl disappeared, indicating that the target structure had been formed.

[0036] Furthermore, the specific degree of substitution and regioselectivity were confirmed by characterization using 1H and 1H NMR spectra. In the 1H NMR spectrum, the proton peak of the unreacted phenolic hydroxyl group in the 10-(2,5-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide structural unit appeared at approximately 9.5 ppm, and the integrated area was consistent with expectations, confirming that only one phenolic hydroxyl group in each 10-(2,5-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide molecule participated in the reaction.

[0037] In the NMR phosphorus spectrum, the chemical shift signal of the phosphorus atom on the phosphazene ring and the signal splitting of the phosphorus atom in the structure correspond perfectly with the target structure, confirming that the modifier with the above specific structure has been synthesized. That is, 0.20 mol of 10-(2,5-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide replaces one chlorine atom on each of two different phosphorus atoms on the hexachlorocyclotriphosphazene ring, and the two substituents are connected in trans configuration in the spatial structure.

[0038] In S2, the two-component coating composition is prepared as follows: Component A is prepared according to the following ratio: 100 parts by weight of waterborne hydroxyl acrylic resin with a solid content of 45% and a hydroxyl value of 80 mg KOH / g, wherein the solid content and hydroxyl value are determined according to relevant national standards; 5 parts by weight of water-dispersible nano-silica with a solid content of 30% and an average particle size of 20 nm, wherein the average particle size is determined by dynamic light scattering method; 0.5 parts by weight of leveling agent; 0.3 parts by weight of defoamer; 0.5 parts by weight of wetting agent; stirred at room temperature for 30 min to obtain a uniformly dispersed component A; Component B is 20 parts by weight of the multifunctional reactive modifier prepared in S1; before use, component A and component B are mixed at an effective ingredient mass ratio of 100:20 and dispersed at high speed at 1500 rpm for 10 min to obtain a coating dispersion;

[0039] In S3, film formation: The obtained coating dispersion is applied to the surface of tinplate and wood substrate by spraying, and the wet film thickness is controlled to be 120μm; after coating, it is left to stand at 30℃ for 20min to allow the moisture to evaporate and promote the migration of fluorine-containing segments to the coating surface; then it is placed in an oven at 100℃ for 45min to cure, resulting in an interpenetrating network coating film with a dry film thickness of about 45μm.

[0040] Example 2:

[0041] The only difference between this embodiment and Embodiment 1 is that the process parameters and formula parameters are located near the lower limit of the protection range; the other operating steps are the same.

[0042] In S1, the molar ratio of hexachlorocyclotriphosphazene, 10-(2,5-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, perfluorohexylethanol and 3-aminopropyltriethoxysilane remains 1:2:2:2, thus preparing a multifunctional reactive modifier.

[0043] In S2, component A consists of 100 parts by weight of waterborne hydroxyl acrylic resin, 5 parts by weight of water-dispersible nano silica, and the same additive system as in Example 1; the amount of component B is adjusted to 15 parts by weight; component A and component B are mixed at an effective ingredient mass ratio of 100:15 and dispersed by high-speed shear for 10 minutes.

[0044] In S3, the coating is applied by roller coating, treated at 25°C for 15 minutes, and then cured at 80°C for 60 minutes to obtain an interpenetrating network coating film.

[0045] Example 3:

[0046] The difference between this embodiment and Embodiment 1 is that the amount of component B added and the curing conditions are at the high end of the protection range, while the other operation steps are the same;

[0047] In S1, the synthesis route and molar ratio of the multifunctional reactive modifier are the same as in Example 1;

[0048] In S2, component A consists of 100 parts by weight of waterborne hydroxyl acrylic resin, 5 parts by weight of water-dispersible nano-silica, and the same additive system as in Example 1; the amount of component B is adjusted to 25 parts by weight; component A and component B are mixed at an effective ingredient mass ratio of 100:25 and dispersed by high-speed shear for 10 minutes.

[0049] In S3, the coating is applied by spraying, treated at 35°C for 25 minutes, and then cured at 110°C for 40 minutes to obtain an interpenetrating network coating.

[0050] Example 4:

[0051] The difference between this embodiment and Embodiment 1 is that the type of matrix resin and some film-forming parameters have changed, while the other operation steps are the same.

[0052] In S1, the synthesis route and molar ratio of the multifunctional reactive modifier are the same as in Example 1;

[0053] In S2, component A consists of 100 parts by weight of an aqueous polyurethane dispersion with a solid content of 42% and a hydroxyl value of 72 mgKOH / g; 5 parts by weight of water-dispersible nano-silica; the amount of other additives is the same as in Example 1; the amount of component B is 30 parts by weight; component A and component B are mixed at an effective ingredient mass ratio of 100:30 and dispersed by high-speed shear for 12 min.

[0054] In S3, the coating is applied by spraying, treated at 40°C for 30 minutes, and then cured at 120°C for 30 minutes to obtain an interpenetrating network coating.

[0055] Comparative Example 1:

[0056] The difference between this comparative example and Example 1 is that the addition of perfluorohexyl ethanol is omitted in step S1, while the other operation steps and process parameters are exactly the same as in Example 1; that is, after intermediate A is formed, hydrophobic segment grafting is not performed, and 3-aminopropyltriethoxysilane is directly added dropwise at 0°C to 5°C to obtain a modifier without fluorinated segments, and coatings and films are prepared according to the method of Example 1.

[0057] Comparative Example 2:

[0058] The difference between this comparative example and Example 1 is that the addition of 3-aminopropyltriethoxysilane is omitted in step S1, while the other operation steps and process parameters are exactly the same as in Example 1; that is, the solvent is directly removed after intermediate B is formed to obtain a modifier without alkoxysilane crosslinking groups, and the coating and film are prepared according to the method of Example 1.

[0059] Comparative Example 3:

[0060] The difference between this comparative example and Example 1 is that water-dispersible nano-silica is omitted in step S2, while other operating steps and process parameters are exactly the same as in Example 1; that is, component A only contains water-based hydroxyl acrylic resin and conventional additives, without the addition of inorganic nanoparticles.

[0061] Comparative Example 4:

[0062] The difference between this comparative example and Example 1 is that the pretreatment stage of 15-30 min at 25℃-40℃ is omitted in step S3, while the other operation steps and process parameters are exactly the same as in Example 1; that is, after the coating dispersion is applied, it is directly placed in a 100℃ oven for curing for 45 min.

[0063] Comparative Example 5:

[0064] The difference between this comparative example and Example 1 is that the mass ratio of the effective components of component A to component B in step S2 is changed from 100:20 to 100:10. Other operating steps and process parameters are exactly the same as in Example 1.

[0065] The basis and conditions for the above performance tests are as follows: water contact angle was measured at room temperature using a contact angle meter; 168h water absorption rate was tested according to GB / T1738 standard; UL-94 flammability rating was tested using a vertical burning test according to GB / T2408 standard; LOI was tested according to GB / T2406 standard; adhesion was tested using the cross-cut test according to GB / T9286 standard; pencil hardness was tested according to GB / T6739 standard. The precipitation of phosphorus in the immersion solution was quantitatively detected using inductively coupled plasma atomic emission spectrometry (ICP-AES) on the aqueous phase after 72 hours of immersion, and the surface phosphorus content was quantitatively determined using X-ray photoelectron spectroscopy (XPS).

[0066] Table 1 Performance Test and Data Table

[0067] Example 1 38.5 126 1.4 V-0 32.5 31.8 Not detected 5B 2H Example 2 31.2 119 2.3 V-0 30.8 29.9 Not detected 5B H Example 3 40.1 128 1.3 V-0 33.1 32.4 Not detected 5B 2H Example 4 41.3 124 1.6 V-0 32.8 32.0 Not detected 5B 2H Comparative Example 1 2.1 88 7.9 V-1 29.4 24.6 Trace detection 4B H Comparative Example 2 36.7 121 5.8 V-0 31.1 22.9 Clearly detected 2B B Comparative Example 3 34.8 116 3.9 V-1 29.8 27.6 Not detected 4B HB Comparative Example 4 14.5 101 4.6 V-1 30.2 28.5 Not detected 4B H Comparative Example 5 25.4 112 3.7 V-2 27.9 25.1 Trace detection 4B HB

[0068] As can be seen from the comparison of the test results of Example 1 and Comparative Example 1 in Table 1, after omitting the fluorinated segment introduced by perfluorohexylethanol, the water contact angle decreased from 126° to 88°, the water absorption rate increased from 1.4% to 7.9% after 168h, and the UL-94 rating decreased from V-0 to V-1.

[0069] The underlying mechanism is that fluorinated segments are the main source of low surface energy structures on the coating surface. Without this structure, it is difficult to form a fluorine-rich surface layer during the film-forming stage, the surface free energy increases, and moisture is more likely to wet and penetrate into the coating film. After moisture enters, it will accelerate the contact between the flame-retardant structure and the external medium, and the continuity of char layer formation will decrease. Therefore, both water resistance and combustion performance will decrease.

[0070] As can be seen from the comparison of the test results of Example 1 and Comparative Example 2 in Table 1, after omitting the alkoxysilane crosslinking group introduced by 3-aminopropyltriethoxysilane, the LOI decreased from 31.8% to 22.9% after 72h soaking, obvious P element appeared in the soaking solution, the adhesion decreased from 5B to 2B, and the hardness decreased from 2H to B.

[0071] The underlying mechanism is that the alkoxysilane group can be hydrolyzed to generate silanol during the curing stage, and further undergo condensation and co-condensation reactions to establish a Si-O-Si inorganic network. At the same time, it forms chemical bonds with the hydroxyl groups on the surface of the resin and nano silica. Without this cross-linking structure, the modifier exists only in the resin phase in a physically dispersed state. It is more likely to migrate and precipitate when immersed in water, resulting in the loss of flame retardant elements. The density of the coating and the interfacial bonding force decrease simultaneously. Therefore, the flame retardant performance, adhesion and hardness are significantly reduced after immersion.

[0072] As can be seen from the comparison of the test results of Example 1 and Comparative Example 3 in Table 1, after omitting the water-dispersible nano silica, the adhesion decreased from 5B to 4B, the hardness decreased from 2H to HB, the UL-94 rating decreased from V-0 to V-1, and the LOI decreased from 32.5% to 29.8%.

[0073] The underlying mechanism is that the hydroxyl groups on the surface of nano-silica can condense with silanols after silane hydrolysis, increasing the crosslinking density of the coating and participating in the formation of silicon-containing inorganic protective phases during combustion. Without nano-silica, the number of inorganic nodes in the interpenetrating network decreases, and the rigidity of the coating and the interfacial anchoring ability decrease. During combustion, the density of the char layer decreases, and the heat insulation and oxygen barrier effects are weakened, so both mechanical properties and fire resistance decrease.

[0074] As can be seen from the comparison of the test results of Example 1 and Comparative Example 4 in Table 1, after omitting the 25℃-40℃ pretreatment stage, the surface F content decreased from 38.5 at.% to 14.5 at.%, the water contact angle decreased from 126° to 101°, the water absorption rate increased to 4.6%, and the UL-94 rating decreased to V-1.

[0075] The underlying mechanism is that the pretreatment stage provides the necessary time for moisture evaporation and interfacial migration of fluorinated segments. If the coating is directly cured at high temperature, the viscosity of the system will increase rapidly and cross-link prematurely, which will restrict the migration and orientation of fluorinated segments and make it difficult to form a significant surface fluorine-rich gradient. When the surface hydrophobic layer is insufficient, the moisture barrier ability will decrease, and the internal structure of the coating will be unevenly distributed, which will also affect the integrity of the protective layer during combustion.

[0076] As can be seen from the comparison of the test results of Example 1 and Comparative Example 5 in Table 1, after the effective component mass ratio of component A to component B was reduced from 100:20 to 100:10, the surface F content, water contact angle, LOI and LOI after immersion all decreased, and the UL-94 rating was reduced from V-0 to V-2.

[0077] The underlying mechanism is that component B has three functions: fluorine-containing segments, phosphorus and nitrogen flame retardant centers, and silane crosslinking end groups. When the amount added is insufficient, the number of low surface energy segments that can migrate on the surface is less, resulting in insufficient hydrophobic layer construction. At the same time, the phosphorus and nitrogen flame retardant elements and polycondensable silane sites in the coating per unit volume are reduced, which causes the carbon layer formation efficiency, crosslinking density, and immersion stability to decrease simultaneously. Therefore, the waterproof, fireproof, and mechanical properties are all lower than those in Example 1.

[0078] Based on the data from Examples 1 to 4, it can be seen that within the scope of this invention, as the amount of component B added, the pretreatment temperature and time, and the curing conditions are adjusted, the resulting coating film can maintain high hydrophobicity and good flame retardancy, indicating that the film-forming method has stable process adaptability.

[0079] The performance of Examples 1, 3, and 4 is quite similar, indicating that within the range of 100:20 to 100:30 for the addition of component B, and with curing conditions of 80℃-120℃, a coating structure with both a hydrophobic surface layer and an internal flame-retardant crosslinked network can be formed. Further comparison of the test results of Examples 2 and 3 shows that Example 2, using a lower pretreatment temperature, a shorter pretreatment time, and a lower amount of component B, has a surface F content of 31.2 at.% and a water contact angle of 119°. In contrast, Example 3, using a pretreatment at 35℃ for 25 minutes and an addition of 25 parts by weight of component B, increases the surface F content to 40.1 at.% and achieves a water contact angle of 128°.

[0080] The underlying mechanism is that higher pretreatment temperature and longer treatment time can more effectively reduce the viscosity of the system, provide the kinetic conditions and time required for the migration of fluorinated segments to the interface between the coating and air, thereby constructing a denser, low surface energy fluorine-rich layer.

[0081] Meanwhile, the curing conditions of 110℃ / 40min in Example 3, compared to the curing conditions of 80℃ / 60min in Example 2, can promote the more complete hydrolysis and polycondensation reaction of the triethoxysilane group introduced by 3-aminopropyltriethoxysilane in the multifunctional reactive modifier, forming a Si-O-Si network with a higher crosslinking density. This further fixes the fluorinated segments that migrate to the surface and prevents them from rearranging during curing or testing. Therefore, it exhibits a better overall effect in terms of surface hydrophobicity, water absorption resistance, and flame retardant properties.

[0082] The above are merely specific embodiments of the present invention and are not intended to limit the present invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments for application in other fields. However, any conventional modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the technical solution of the present invention shall still fall within the protection scope of the technical solution of the present invention.

Claims

1. A method for forming a film of a coating that combines waterproof and fireproof properties, characterized in that, Includes the following steps: Step 1, Preparation of the multifunctional reactive modifier: Hexachlorocyclotriphosphazene, 10-(2,5-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, perfluorohexylethanol and 3-aminopropyltriethoxysilane are reacted to prepare the multifunctional reactive modifier. Step 2, Preparation of the two-component coating composition: Hydroxyl-containing aqueous matrix resin and water-dispersible inorganic nanoparticles are mixed evenly to obtain component A; the multifunctional reactive modifier prepared in step 1 is used as component B; component A and component B are mixed and dispersed at an effective component mass ratio of 100:15 to 100:30 to obtain a coating dispersion; the mass of the effective component refers to the sum of the mass of the solid resin portion of the aqueous matrix resin and the solid particle portion of the water-dispersible inorganic nanoparticles in component A, and the pure substance mass of the multifunctional reactive modifier in component B. Step 3, film formation: The coating dispersion is coated onto the surface of the substrate, dried to allow the moisture and solvent to evaporate, and then heated to cure, forming an interpenetrating network coating film on the surface of the substrate.

2. The film-forming method for the waterproof and fireproof coating according to claim 1, characterized in that, The preparation of the multifunctional reactive modifier described in step one specifically includes the following steps: (1) Under inert gas protection, hexachlorocyclotriphosphazene was dissolved in anhydrous tetrahydrofuran, and triethylamine was added to obtain a first solution; 10-(2,5-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide was dissolved in anhydrous tetrahydrofuran to obtain a second solution; the second solution was added dropwise to the first solution for reflux reaction, cooled and filtered to obtain intermediate A solution; (2) Add perfluorohexylethanol and anhydrous potassium carbonate to the intermediate A solution and react. After cooling, filter to obtain intermediate B solution. (3) Cool the intermediate B solution to an ice-water bath, add triethylamine as an acid-binding agent, add 3-aminopropyltriethoxysilane dropwise, and after the addition is complete, restore the room temperature to carry out the reaction. After the reaction is completed, filter the solution and remove the solvent by rotary evaporation under reduced pressure to obtain the multifunctional reactive modifier.

3. The film-forming method for the waterproof and fireproof coating according to claim 2, characterized in that, In step one: The molar ratio of the hexachlorocyclotriphosphazene to the 10-(2,5-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is 1:

2. The reflux reaction conditions described in step one (1) are to raise the temperature to 65°C and carry it out for 12 hours; The reaction conditions described in step one (2) are to raise the temperature to 65°C and carry out the reaction for 10 hours; The temperature of the ice-water bath described in step one (3) is 0°C to 5°C. After the addition is completed, the temperature is restored to 25°C and the reaction is carried out for 6 hours.

4. The film-forming method for the waterproof and fireproof coating according to claim 1, characterized in that, In step two, the hydroxyl-containing aqueous matrix resin is an aqueous hydroxyl acrylic resin or an aqueous polyurethane dispersion.

5. The film-forming method for the waterproof and fireproof coating according to claim 1, characterized in that, In step two, the water-dispersible inorganic nanoparticles are water-dispersible nano-silica.

6. The film-forming method for the waterproof and fireproof coating according to claim 1, characterized in that, In step three, the coating dispersion is applied to the substrate surface by spraying or roller coating.

7. The film-forming method for the waterproof and fireproof coating according to claim 5, characterized in that, In step three, the fluorine element in the interpenetrating network coating formed after curing decreases from the outer surface to the interior along the thickness direction of the interpenetrating network coating.

8. The film-forming method for the waterproof and fireproof coating according to claim 6, characterized in that, In step two: the dispersion conditions are shear dispersion at 25°C and a rotation speed of 1500 rpm.

9. The film-forming method for the waterproof and fireproof coating according to claim 7, characterized in that, In step three: the treatment to evaporate moisture and solvent specifically involves treating at 25°C to 40°C for 15 to 30 minutes to evaporate moisture and solvent; the curing specifically involves heating to 80°C to 120°C for 30 to 60 minutes to cure.