An inorganic water-resistant flame retardant coating and its preparation method

Abstract

The present invention discloses an inorganic water-resistant flame retardant material and a preparation method thereof. The inorganic water-resistant flame retardant material mainly consists of water, phosphate, lithium silicate, hydrophobic flame retardant particles, jade powder, kaolin, heavy calcium, dispersant, thickener, and defoamer. By using the fact that a magnesium salt compound and a titanium-containing compound can form a layered compound, fixing the anions of the phosphate in the interlayer, and the titanium can be hydrophobically modified to prepare the hydrophobic flame retardant particles, a three-dimensional network structure is formed with the lithium silicate, thereby chemically bonding each raw material, enhancing its compatibility and the strength of the coating. It overcomes the problem of poor compatibility of the phosphate when added alone as a coating component, enabling the building wall or building material to have better high-temperature resistance, waterproof, fireproof and other properties after using the coating of the present application. Because the hydrophobicity and the compatibility of the components can reduce the coating damage and powdering caused by water wetting and scouring, the service life in a humid and rainy environment is greatly extended.

Description

Technical Field

[0001] The present invention belongs to the technical field of inorganic coatings, and relates to an inorganic water-resistant and flame-retardant coating and a preparation method thereof. Background Art

[0002] Inorganic coatings are mainly composed of inorganic substances, and have excellent environmental protection, antibacterial and mildew-proof, water-permeable and breathable, fire-resistant and heat-resistant properties, meeting the requirements of people for energy conservation and environmental protection of contemporary building materials. Therefore, as an environmentally friendly flame-retardant coating, it is favored by people.

[0003] However, inorganic coatings are prepared by mixing inorganic substances. The inorganic substances in the prepared inorganic coatings are often simple physical mixtures. After being used to form a film on the surface of the substrate, there is often a lack of sufficient adhesion between the inorganic components; especially in the humid climate in the south, after being soaked and washed by rainwater for a long time, the adhesiveness between the inorganic components further decreases, and the adhesiveness of the coating layer decreases, thus affecting the protection function of the coating layer. Especially for the coating layer with flame-retardant performance, due to the addition of flame-retardant components, the flame-retardant components are dispersed in the film-forming substances, which may reduce the adhesiveness between the coating components. After being soaked for a long time, the flame-retardant performance of the coating layer decreases, posing a safety hazard. Therefore, enhancing the compatibility between the inorganic components of the inorganic coating to improve the strength of the coating layer is a problem that the inorganic coating must overcome. Summary of the Invention

[0004] In order to overcome the deficiencies of the prior art, the first object of the present invention is to provide an inorganic water-resistant and flame-retardant coating, which reduces the influence of the addition of traditional flame retardants on the adhesiveness of the coating, and increases the hydrophobic property to further improve the water resistance to infiltration and erosion.

[0005] The second object of the present invention is to provide a preparation method of the above-mentioned inorganic water-resistant and flame-retardant coating.

[0006] The first object of the present invention can be achieved by adopting the following technical solutions:

[0007] An inorganic water-resistant and flame-retardant coating, in parts by weight, comprises the following components:

[0008] 25 - 40 parts of water, 5 - 35 parts of lithium silicate, 5 - 20 parts of hydrophobic flame-retardant particles, 5 - 15 parts of jade powder, 5 - 8 parts of kaolin, 5 - 10 parts of heavy calcium, 1 - 4 parts of dispersant, 2 - 4 parts of thickener, 1 - 4 parts of defoamer.

[0009] Further, in parts by weight, it comprises the following components: 25 - 35 parts of water, 10 - 30 parts of lithium silicate, 10 - 15 parts of hydrophobic flame-retardant particles, 8 - 12 parts of jade powder, 6 - 7 parts of kaolin, 6 - 8 parts of heavy calcium, 2 - 3 parts of dispersant, 3 - 4 parts of thickener, 2 - 3 parts of defoamer.

[0010] Furthermore, the preparation method of the hydrophobic flame retardant particles is as follows:

[0011] S31. Add triethoxyalkylsilane, titanate and hydrochloric acid into an ethanol solution to obtain a mixture;

[0012] S32. Add a magnesium salt and an aqueous phosphate solution to the mixed solution obtained in step S31, stir evenly, adjust the pH and stir for reaction. After the reaction ends, the hydrophobic flame retardant particles are obtained.

[0013] Furthermore, in step S31, the alkyl group in the triethoxyalkylsilane is a branched chain or branched alkane with C8-C18.

[0014] Furthermore, the titanate is tetrabutyl titanate, or tetraisopropyl titanate, or tetraethyl titanate.

[0015] Furthermore, the molar ratio of triethoxyalkylsilane, titanate and hydrochloric acid is (0.5-1):1:(0.01-0.1).

[0016] Furthermore, in step S32, the magnesium salt is magnesium chloride.

[0017] Furthermore, the phosphate is one or a combination of two or more of ammonium phosphate, sodium phosphate, and potassium phosphate.

[0018] Furthermore, the molar ratio of magnesium to titanate in the magnesium salt is (2.5-3.5):1, and the addition amount of the phosphate is (0.2-0.5) of the molar amount of the titanate.

[0019] Furthermore, in step S32, after adjusting the pH to 10-11, the reaction is carried out at 60-80°C for 3-10 h.

[0020] Furthermore, after the reaction in step S32 ends, the reactants are aged at 50-70°C for 5-24 h, the solid is collected by centrifugation, and after wet grinding, the hydrophobic flame retardant particles are obtained.

[0021] Furthermore, in the lithium silicate, the molar ratio of SiO 2 and Li 2 O is 4.5-10.

[0022] The second object of the present invention can be achieved by adopting the following technical solutions:

[0023] A preparation method of an inorganic water-resistant flame retardant coating, comprising the following steps:

[0024] S11. Pour lithium silicate, hydrophobic flame retardant particles and jade powder into a stirring device for mixing and stirring, and add water during stirring to obtain a mixed solution;

[0025] S12. Add an antifoaming agent, a thickening agent, and a dispersing agent to the mixed solution prepared in S11, and continue stirring to obtain a mixed coating.

[0026] S13. After there are no obvious bubbles in the mixed coating prepared in S12, add kaolin and heavy calcium, and continue stirring for 30 - 80 min to obtain the finished product of the inorganic water-resistant and flame-retardant coating.

[0027] Furthermore, the rotation speed of the stirring device is controlled at 200 - 400 r / min, and the stirring temperature is 20 - 30 °C.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] 1. The present invention provides an inorganic water-resistant and flame-retardant coating, in which the hydrophobic flame-retardant particles provide strong flame retardancy for the coating; and the hydrophobic flame-retardant particles can be incorporated into lithium silicate, with good compatibility, without weakening the overall mechanical properties of the coating, and also providing inorganic and organic hydrophobic effects; the lithium silicate has excellent water resistance, and after combining with the hydrophobic flame-retardant particles and coating on the surface of the wall or building material, the wall or building material has better properties such as high temperature resistance, waterproofing, and fire protection. In particular, its hydrophobicity can reduce the damage and powdering of the coating caused by water wetting and scouring, so the protection of the wall or building material is greatly enhanced in a humid and rainy environment.

[0030] 2. This kind of inorganic water-resistant and flame-retardant coating can quickly obtain an inorganic coating with excellent quality through a simple preparation method. After the coating is applied to the surface of the mineral matrix, it is resistant to water infiltration and scouring, avoiding the powdering of the coating. Description of the Drawings

[0031] Figure 1 It is the water contact angle diagram of Comparative Example 1;

[0032] Figure 2 It is the water contact angle diagram of Comparative Example 5;

[0033] Figure 3 It is the water contact angle diagram of Example 4. Specific Embodiments

[0034] Next, in combination with specific embodiments, the present invention will be further described:

[0035] In order to increase the flame retardancy and water resistance of inorganic coatings, some phosphate substances and water-resistant components are often added. These components are mixed with the basic component of inorganic coatings, silicate, and dispersed in the film-forming substance. The differences between different components may lead to a decrease in the adhesiveness between the formed coating components. In the humid environment in the south, after long-term immersion, especially under rain erosion, the protective performance of the coating decreases, making the coating easily damaged, and its flame retardancy also decreases, posing a safety hazard. Therefore, enhancing the compatibility between inorganic components of inorganic coatings to improve the strength of the coating is a problem that inorganic coatings must overcome. The present invention provides an inorganic water-resistant and flame-retardant coating to solve the problem of the compatibility between flame-retardant components and the coating, and make the coating have excellent strength and water resistance.

[0036] An inorganic water-resistant and flame-retardant coating, by weight, comprises the following components:

[0037] 25 - 40 parts of water, 5 - 35 parts of lithium silicate, 5 - 20 parts of hydrophobic flame-retardant particles, 5 - 15 parts of jade powder, 5 - 8 parts of kaolin, 5 - 10 parts of heavy calcium, 1 - 4 parts of dispersant, 2 - 4 parts of thickener, 1 - 4 parts of defoamer.

[0038] As a preferred embodiment, by weight, it comprises the following components: 25 - 35 parts of water, 10 - 30 parts of lithium silicate, 10 - 15 parts of hydrophobic flame-retardant particles, 8 - 12 parts of jade powder, 6 - 7 parts of kaolin, 6 - 8 parts of heavy calcium, 2 - 3 parts of dispersant, 3 - 4 parts of thickener, 2 - 3 parts of defoamer.

[0039] Silicate is the basic component of inorganic coatings, but its water resistance is poor and it is not suitable for use in humid and alkaline environments. The water glass of the present invention is lithium silicate-based, has self-drying property, and can form a water-insoluble dry film, with excellent resistance to dry-wet cycling, and is particularly suitable for humid environments and water-resistant coatings. However, the dry film formed by lithium silicate has poor continuity and adhesion; therefore, based on prior research, the present invention mixes lithium silicate-based water glass with hydrophobic flame-retardant particles, jade powder, kaolin, and heavy calcium to enhance its film-forming property, water resistance, and flame retardancy.

[0040] The hydrophobic flame-retardant particles are lamellar inorganic lamellar structure particles formed by Mg and Ti. Mg in the inorganic lamellar structure particles can undergo a condensation reaction with lithium silicate, bind to the silicate-based water glass as a connection site or interpenetrate into the silicate to form a network structure. On the one hand, the inorganic lamellar structure particles are fixed in the coating, increasing the compatibility between components and improving the adhesion strength of the coating to the substrate, so that it is not easy to fall off; on the other hand, phosphate radicals with good flame-retardant properties are interspersed between the lamellae of the inorganic lamellar structure particles, and the flame-retardant properties of the inorganic lamellar structure itself and the flame-retardant properties of the phosphate radicals synergistically increase the flame-retardant properties of the coating. The lamellar structure of the inorganic lamellar structure particles themselves has certain hydrophobicity and flame retardancy, and the presence of Ti makes the coating film smooth after film formation, increasing the hydrophobicity; and the surface of Ti is modified with long-chain alkanes, providing organic hydrophobicity and further reducing the hydrophobicity of the coating.

[0041] As a preferred embodiment, the preparation method of the hydrophobic flame-retardant particles is as follows:

[0042] S31. Add triethoxyalkylsilane, titanate and hydrochloric acid into an ethanol solution to obtain a mixture;

[0043] S32. Add a magnesium salt and an aqueous phosphate solution to the mixed solution obtained in step S31, stir evenly, adjust the pH and stir for reaction. After the reaction is completed, the hydrophobic flame-retardant particles are obtained.

[0044] Triethoxyalkylsilane and titanate react in an ethanol solution of hydrochloric acid. The silicon in the silane is connected to titanium through an oxygen bond, and the alkyl group connected to the silane is modified onto titanium. Then, a magnesium salt and an aqueous phosphate solution are continuously added. The titanium-containing compound undergoes hydrolysis. By adjusting the pH, it reacts with the magnesium salt to form lamellar inorganic lamellar structure particles containing Mg and Ti through coprecipitation. Among them, the phosphate anions in the phosphate replace the anions in the inorganic lamellar structure and are interspersed between the lamellae of the inorganic lamellar structure particles to obtain hydrophobic flame-retardant particles.

[0045] Therefore, the formed hydrophobic flame-retardant particles are inorganic lamellar structure particles containing Mg and Ti prepared by co-precipitation method, which have a layered structure and interlayer ions. When the hydrophobic flame-retardant particles are heated, the hydroxyl groups on the lamellar and the phosphate groups between the layers will detach and release, reducing the high temperature generated during combustion; and they can also form a dense layer to prevent oxygen from entering the interior of the material for combustion. More importantly, the presence of Mg enables the hydrophobic flame-retardant particles to combine with silicate. The silicate component of the coating is connected to the hydrophobic flame-retardant particles through chemical bonds. On the one hand, the hydrophobic flame-retardant particles are compatibly fixed in the coating, avoiding the problem of insufficient film-forming adhesive strength of the coating caused by the compatibility problem between the addition of phosphate and each component. On the other hand, lithium silicate and the hydrophobic flame-retardant particles are combined to form a network structure, and the magnesium compound molecules are interspersed between Si-O to form a three-dimensional interpenetrating network structure, increasing the cross-linking degree of the silicate to form a network structure and improving the adhesion strength of the coating to the substrate, so that it is not easy to fall off. And the hydrophobic flame-retardant particles can also provide hydrophobic properties. The Ti contained therein, in addition to being modified by an alkyl group, enables the coating to have corresponding organic hydrophobic properties; and the presence of Ti can also make the surface of the coating film smoother and reduce the adhesion of water.

[0046] As a preferred embodiment, in the step S31, the alkyl group in the triethoxyalkylsilane is a branched or branched alkane with C8-C18. The use of long-chain alkanes can provide better hydrophobicity. If the alkyl chain is too short, the hydrophobic property is not sufficient; if the alkyl chain is too long, it is not easy to disperse when combined with Ti and added to the coating. Therefore, preferably, the alkyl group in the triethoxyalkylsilane is a branched or branched alkane with C10-C16.

[0047] As a preferred embodiment, the titanate is tetrabutyl titanate or tetraisopropyl titanate or tetraethyl titanate. Considering the accessibility and reactivity of the titanate, tetrabutyl titanate or tetraisopropyl titanate or tetraethyl titanate is selected as a better raw material.

[0048] As a preferred embodiment, the molar ratio of triethoxyalkylsilane, titanate and hydrochloric acid is (0.5-1):1:(0.01-0.1). If the amount of triethoxyalkylsilane used is too much, it may have an adverse effect on the subsequent hydrolysis co-precipitation of the titanate; if the amount used is too little, it is difficult to ensure the organic hydrophobicity of the hydrophobic flame-retardant particles.

[0049] As a preferred embodiment, the magnesium salt in the step S32 is magnesium chloride. The chloride anions provided by magnesium chloride in the co-precipitation can be better replaced by phosphate ions, so that the phosphate ions are interspersed between the layered structures as interlayer anions.

[0050] As a preferred embodiment, the phosphate is one or a combination of two or more of ammonium phosphate, sodium phosphate, and potassium phosphate. Phosphate is an excellent common inorganic flame retardant. Therefore, using the above-mentioned phosphate will not cause a large change to the flame retardant components of the existing coatings, and thus will not deviate from the corresponding standards or specifications.

[0051] As a preferred embodiment, the molar ratio of magnesium to titanate in the magnesium salt is (2.5 - 3.5):1, and the addition amount of the phosphate is (0.2 - 0.5) times the molar amount of the titanate. Phosphate groups are intercalated between the layers. If the phosphate group content is low, it cannot achieve a sufficient flame retardant effect. Therefore, the molar amount of the phosphate group is limited to (0.2 - 0.5) times the molar amount of the titanate.

[0052] As a preferred embodiment, in step S32, after adjusting the pH to 10 - 11, the reaction is carried out at 60 - 80 °C for 3 - 10 h. The pH is related to the formation of hydrophobic flame retardant particles by coprecipitation. Therefore, between pH 10 - 11, Mg and Ti coprecipitate at a certain rate to form a double hydroxide layer, obtaining inorganic lamellar structure particles.

[0053] As a preferred embodiment, after the reaction in step S32 is completed, the reactants are aged at 50 - 70 °C for 5 - 24 h, the solid is collected by centrifugation, and after wet grinding, the hydrophobic flame retardant particles are obtained.

[0054] As a preferred embodiment, in the lithium silicate 2 and Li 2 The molar ratio of O is 4.5 - 10. Generally speaking, the larger the modulus of sodium silicate, the more difficult it is for solid sodium silicate to dissolve in water. However, for lithium silicate, with an SiO 2 to Li 2When used in a molar ratio of 0, when the modulus is small, the particle size of the micelle particles in lithium silicate is small and the dispersion is good. As the modulus increases, the particle size of the micelle particles becomes larger, and the micelle particles form a chain structure through the bonding of Si-O bases. As the modulus reaches above 4.5, the bonding degree between the Si-O bases of the micelle particles in the solution further increases and expands from one dimension to two dimensions to form a network structure. However, as the modulus increases, the dispersion degree is too low and not suitable for uniform film formation; therefore, in the prior art, lithium silicate is mixed with a flame retardant component, and the interaction between different components makes the dispersion worse, the film formation non-uniformity stronger, and the film performance deteriorates. In this application, the hydrophobic flame retardant particles can combine with lithium silicate, so the dispersion degree of lithium silicate is greatly increased, enabling lithium silicate with a modulus of up to 10 to form a film well, and the formed film has excellent performance; therefore, the modulus of the lithium silicate in this application is further broadened. On the one hand, lithium silicate with such a high molar ratio can dissolve in water and has excellent water resistance, which can help improve the water resistance and heat resistance of the coating film of the composition of the present invention; on the other hand, the selection range of raw materials is expanded, which is beneficial to reducing the raw material cost and improving the market acceptance of the inorganic water-resistant flame retardant coating.

[0055] As a preferred embodiment, the dispersant is a conventional dispersant, which can be one or a combination of two or more of BYK190, Dego740W, and 5040.

[0056] As a preferred embodiment, the thickener can be hydroxyethyl cellulose.

[0057] As a preferred embodiment, the defoamer is one or a combination of two or more of BYK024, TEGO810, and DC-65.

[0058] The present invention also provides a preparation method of an inorganic water-resistant flame retardant coating, comprising the following steps:

[0059] S11. Pour lithium silicate, hydrophobic flame retardant particles, and nephrite powder into a stirring device for mixing and stirring, and add water during stirring to obtain a mixed solution;

[0060] S12. Add a defoamer, a thickener, and a dispersant to the mixed solution prepared in S11, and continue stirring to obtain a mixed coating;

[0061] S13. After the mixed coating prepared in S12 has no obvious bubbles, add kaolin and heavy calcium, and continue stirring for 30 - 80 min to obtain the finished product of the inorganic water-resistant flame retardant coating.

[0062] Pour lithium silicate, hydrophobic flame-retardant particles and jade powder into a stirring device and stir first, then add water to make the mixture of various substances more uniform, so that the reaction is more uniform and thorough. Then add other raw materials to make each component evenly dispersed in the film-forming substance, making the coating more stable and the substances in the coating uniform after application.

[0063] As a preferred embodiment, the rotation speed of the stirring device is controlled at 200 - 400 r / min, and the stirring temperature is 20 - 30 °C. At this stirring speed, both the stirring and mixing effects can be achieved, and at the same time, the generation of excessive bubbles due to too high a rotation speed can be prevented; while at a relatively low temperature, the various reactions in the coating can be ensured to proceed, and the preparation of the coating has low limitations.

[0064] Example 1: Preparation of Hydrophobic Flame-Retardant Particles

[0065] Add 0.75 mol of dodecyltriethoxysilane, 1 mol of tetrabutyl titanate and 0.07 mol of hydrochloric acid to an ethanol solution, stir evenly, then add an aqueous solution of 3 mol of magnesium chloride and 0.35 mol of ammonium phosphate, stir evenly, adjust the pH to 11, stir and react at 70 °C for 7 h; age the reactant at 60 °C for 12 h, centrifuge to collect the solid, and after wet grinding, obtain the hydrophobic flame-retardant particles.

[0066] Example 2: Preparation of Hydrophobic Flame-Retardant Particles

[0067] Add 0.5 mol of octadecyltriethoxysilane, 1 mol of tetraisopropyl titanate and 0.01 mol of hydrochloric acid to an ethanol solution, stir evenly, then add an aqueous solution of 2.5 mol of magnesium chloride and 0.2 mol of sodium phosphate, stir evenly, adjust the pH to 10, stir and react at 60 °C for 10 h; age the reactant at 50 °C for 24 h, centrifuge to collect the solid, and after wet grinding, obtain the hydrophobic flame-retardant particles.

[0068] Example 3: Preparation of Hydrophobic Flame-Retardant Particles

[0069] Add 1 mol of octyltriethoxysilane, 1 mol of tetraethyl titanate and 0.1 mol of hydrochloric acid to an ethanol solution, stir evenly, then add an aqueous solution of 3.5 mol of magnesium chloride and 0.5 mol of potassium phosphate, stir evenly, adjust the pH to 11, stir and react at 80 °C for 3 h; age the reactant at 70 °C for 5 h, centrifuge to collect the solid, and after wet grinding, obtain the hydrophobic flame-retardant particles.

[0070] Example 4:

[0071] Pour 10 parts of lithium silicate with a modulus of 4.5, 10 parts of the hydrophobic flame-retardant particles prepared in Example 1, and 5 parts of jade powder into a stirring device for mixing and stirring. During stirring, add 33 parts of water to obtain a mixed solution; add 1 part of BYK024 defoamer, 2 parts of hydroxyethyl cellulose, and 1 part of BYK1901 dispersant to the above mixed solution, and continue stirring. After there are no obvious bubbles in the mixed coating, add 5 parts of kaolin and 5 parts of heavy calcium, and continue stirring for 30 min to obtain the finished inorganic coating product.

[0072] Example 5:

[0073] Pour 20 parts of lithium silicate with a modulus of 5.5, 5 parts of the hydrophobic flame-retardant particles prepared in Example 2, and 8 parts of jade powder into a stirring device for mixing and stirring. During stirring, add 36 parts of water to obtain a mixed solution; add 2 parts of TEGO810 defoamer, 3 parts of hydroxyethyl cellulose, and 2 parts of Dego740W dispersant to the above mixed solution, and continue stirring. After there are no obvious bubbles in the mixed coating, add 6 parts of kaolin and 6 parts of heavy calcium, and continue stirring for 40 min to obtain the finished inorganic coating product.

[0074] Example 6:

[0075] Pour 30 parts of lithium silicate with a modulus of 6, 15 parts of the hydrophobic flame-retardant particles prepared in Example 1, and 12 parts of jade powder into a stirring device for mixing and stirring. During stirring, add 41 parts of water to obtain a mixed solution; add 3 parts of DC-65 defoamer, 2 parts of hydroxyethyl cellulose, and 3 parts of 5040 dispersant to the above mixed solution, and continue stirring. After there are no obvious bubbles in the mixed coating, add 7 parts of kaolin and 8 parts of heavy calcium, and continue stirring for 50 min to obtain the finished inorganic coating product.

[0076] Example 7:

[0077] Pour 5 parts of lithium silicate with a modulus of 7.5, 20 parts of the hydrophobic flame-retardant particles prepared in Example 1, and 15 parts of jade powder into a stirring device for mixing and stirring. During stirring, add 45 parts of water to obtain a mixed solution; add 4 parts of BYK024 defoamer, 4 parts of hydroxyethyl cellulose, and 4 parts of BYK1901 dispersant to the above mixed solution, and continue stirring. After there are no obvious bubbles in the mixed coating, add 8 parts of kaolin and 10 parts of heavy calcium, and continue stirring for 60 min to obtain the finished inorganic coating product.

[0078] Example 8:

[0079] Pour 35 parts of lithium silicate with a modulus of 8.5, 13 parts of the hydrophobic flame-retardant particles prepared in Example 2, and 10 parts of jade powder into a stirring device for mixing and stirring. During stirring, add 40 parts of water to obtain a mixed solution; add 2.5 parts of TEGO810 defoamer, 3 parts of hydroxyethyl cellulose, and 2.5 parts of BYK1901 dispersant to the above mixed solution, and continue stirring. After the mixed coating has no obvious bubbles, add 6 parts of sodium phosphate, 6.5 parts of kaolin, and 7.5 parts of heavy calcium, and continue stirring for 80 min to obtain the finished inorganic coating product.

[0080] Example 9:

[0081] Pour 15 parts of lithium silicate with a modulus of 10, 7 parts of the hydrophobic flame-retardant particles prepared in Example 3, and 10 parts of jade powder into a stirring device for mixing and stirring. During stirring, add 40 parts of water to obtain a mixed solution; add 2.5 parts of TEGO810 defoamer, 3 parts of hydroxyethyl cellulose, and 2.5 parts of BYK1901 dispersant to the above mixed solution, and continue stirring. After the mixed coating has no obvious bubbles, add 6.5 parts of kaolin and 7.5 parts of heavy calcium, and continue stirring for 80 min to obtain the finished inorganic coating product.

[0082] Comparative Example 1

[0083] Pour 10 parts of lithium silicate with a modulus of 4.5, 2.5 parts of modified silica, 1 part of magnesium oxide, and 5 parts of jade powder into a stirring device for mixing and stirring. During stirring, add 33 parts of water to obtain a mixed solution; add 1 part of BYK024 defoamer, 2 parts of hydroxyethyl cellulose, and 1 part of BYK1901 dispersant to the above mixed solution, and continue stirring. After the mixed coating has no obvious bubbles, add 5 parts of ammonium phosphate, 5 parts of kaolin, and 5 parts of heavy calcium, and continue stirring for 30 min to obtain the finished inorganic coating product;

[0084] The modified silica is prepared by the following method:

[0085] Add tetraethyl orthosilicate, (2,3-epoxypropoxy)propyltrimethoxysilane, and hydrochloric acid in a ratio of 1:0.10:0.01 to an anhydrous ethanol solution, stir evenly, add cetyltrimethoxysilane of 0.5% tetraethyl orthosilicate to the above mixed solution, stir at room temperature for 7 h, then add cetyltrimethoxysilane of 0.5% tetraethyl orthosilicate again and continue stirring at room temperature for 16 h. After the reaction, freeze-dry to remove the solvent to obtain the modified silica.

[0086] Comparative Example 2

[0087] Pour 10 parts of lithium silicate with a modulus of 4.5 and 5 parts of jade powder into a stirring device for mixing and stirring. During stirring, add 33 parts of water to obtain a mixed solution; add 1 part of BYK024 defoamer, 2 parts of hydroxyethyl cellulose, and 1 part of BYK1901 dispersant to the above mixed solution, and continue stirring. After the mixed coating has no obvious bubbles, add 5 parts of kaolin and 5 parts of heavy calcium, and continue stirring for 30 minutes to obtain the finished inorganic coating product.

[0088] Comparative Example 3

[0089] Pour 10 parts of lithium silicate with a modulus of 4.5, 2.5 parts of hydrophobic particles, and 5 parts of jade powder into a stirring device for mixing and stirring. During stirring, add 33 parts of water to obtain a mixed solution; add 1 part of BYK024 defoamer, 2 parts of hydroxyethyl cellulose, and 1 part of BYK1901 dispersant to the above mixed solution, and continue stirring. After the mixed coating has no obvious bubbles, add 5 parts of kaolin and 5 parts of heavy calcium, and continue stirring for 30 minutes to obtain the finished inorganic coating product;

[0090] The hydrophobic particles are prepared by the following method:

[0091] Add 0.75 mol of dodecyltriethoxysilane, 1 mol of tetrabutyl titanate, and 0.07 mol of hydrochloric acid to an ethanol solution, stir evenly, then add an aqueous solution of 3 mol of magnesium chloride, stir evenly, adjust the pH to 11, stir and react, and carry out the reaction at 70 °C for 7 h; age the reactants at 60 °C for 12 h, centrifuge to collect the solid, and after wet grinding, obtain the hydrophobic flame-retardant particles.

[0092] Comparative Example 4

[0093] Pour 10 parts of lithium silicate with a modulus of 4.5, 2.5 parts of hydrophobic particles, and 5 parts of jade powder into a stirring device for mixing and stirring. During stirring, add 33 parts of water to obtain a mixed solution; add 1 part of BYK024 defoamer, 2 parts of hydroxyethyl cellulose, and 1 part of BYK1901 dispersant to the above mixed solution, and continue stirring. After the mixed coating has no obvious bubbles, add 5 parts of ammonium phosphate; 5 parts of kaolin and 5 parts of heavy calcium, and continue stirring for 30 minutes to obtain the finished inorganic coating product;

[0094] The hydrophobic particles are prepared by the following method:

[0095] Add 0.75 mol of dodecyltriethoxysilane, 1 mol of tetrabutyl titanate, and 0.07 mol of hydrochloric acid to an ethanol solution, stir evenly, then add an aqueous solution of 3 mol of magnesium chloride, stir evenly, adjust the pH to 11, stir and react, and carry out the reaction at 70 °C for 7 h; age the reactants at 60 °C for 12 h, centrifuge to collect the solid, and after wet grinding, obtain the hydrophobic flame-retardant particles.

[0096] Comparative Example 5

[0097] 10 parts of lithium water glass with a modulus of 4.5, 2.5 parts of flame retardant particles, and 5 parts of jade powder were poured into a stirring device for mixing and stirring. During stirring, 33 parts of water were added to obtain a mixed solution; 1 part of BYK024 defoamer, 2 parts of hydroxyethyl cellulose, and 1 part of BYK1901 dispersant were added to the above mixed solution. After continuous stirring until there were no obvious bubbles in the mixed coating, 5 parts of kaolin and 5 parts of heavy calcium were added, and stirring continued for 30 min to obtain the finished inorganic coating product.

[0098] The flame retardant particles were prepared by the following preparation method:

[0099] 1 mol of tetrabutyl titanate and 0.07 mol of hydrochloric acid were added to an ethanol solution, stirred evenly, then an aqueous solution of 3 mol of magnesium chloride and 0.35 mol of ammonium phosphate was added, stirred evenly, the pH was adjusted to 11, and stirring reaction was carried out at 70 °C for 7 h; the reactants were aged at 60 °C for 12 h, the solid was collected by centrifugation, and after wet grinding, the hydrophobic flame retardant particles were obtained.

[0100] Performance testing:

[0101] Material hydrophobicity test: The coatings of Comparative Example 1, Comparative Example 5, and Example 4 were applied on an asbestos-free fiber cement flat plate, and the contact angle of the water domain coating interface was measured with a PZ-200SD type hydrophobicity tester. The water contact angle of Comparative Example 1 was as Figure 1 shown, where the contact angle was about 138°, showing hydrophobicity; the water contact angle of Comparative Example 5 was as Figure 2 shown, where the contact angle was about 101°, showing hydrophobicity; the water contact angle of Example 4 was as Figure 3 shown, where the contact angle was about 135°, all showing hydrophobicity.

[0102] Flammability detection:

[0103] According to the national standard for classification of the burning performance of building materials and products GB8624-2012, the burning grades of the coatings of Example 4 and Comparative Examples 1-5 were all Class A. However, ammonium phosphate flame retardant was added in Example 4, Comparative Example 1, and Comparative Examples 4-5, and its flame retardant effect was better than that of Comparative Examples 2-3 without ammonium phosphate flame retardant.

[0104] Coating wash resistance test: The coatings of Examples 4-9 and Comparative Examples 1-5 were tested according to the regulations in GB / T 9266-2009 "Determination of scrub resistance of building paint coatings". The scrubbing medium was deionized water, and the results are shown in Table 1.

[0105] Table 1 Detection results of coating wash resistance.

[0106] Example 3 Example 4 Example 5 Example 6 Example 7 Scrub resistance / times 5312 5255 5408 5306 5324 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Scrub resistance / times 3879 2034 5287 4136 2867

[0107] As can be seen from Table 1, the coating of the present invention has excellent erosion resistance when deionized water is used as the washing medium. The coating will be damaged only after being washed more than 5,200 times according to GB / T 9266-2009. In Comparative Example 1, modified silica is used and ammonium phosphate flame retardant is added alone. The number of erosion resistance times is close to 3,900 times, indicating that the hydrophobicity of the hydrophobic groups in the modified silica can effectively avoid the wetting and erosion of the coating by water during the washing process and slow down the friction of washing. However, it is lower than more than 5,200 times of this application, which shows that the addition of phosphate has an impact on the erosion resistance performance; this can be seen more clearly from Comparative Example 3 and Comparative Example 4. In Comparative Example 3, ammonium phosphate is not added alone and the hydrophobic particles do not contain ammonium phosphate. Therefore, the number of erosion resistance times in Comparative Example 3 is similar to that in the Examples. However, after ammonium phosphate is added alone in Comparative Example 4, the number of erosion resistance times drops to about 4,100. This fully reflects that the addition of the flame retardant ammonium phosphate reduces the compatibility with other components and reduces the strength of the coating, which is reflected in the significant reduction of the number of erosion resistance times.

[0108] In Comparative Example 5, the flame retardant particles were not hydrophobically modified, and the number of erosion resistance times of the coating decreased significantly. This is because the hydrophobicity of the hydrophobic groups can effectively avoid the wetting and erosion of the coating by water during the washing process and slow down the friction of washing. The increase in the number of erosion resistance times compared to Comparative Example 2 is due to the inorganic lamellar structure containing Mg and Ti in the flame retardant particles, and the role of the three-dimensional network structure formed by Mg and lithium silicate in hydrophobicity and coating stability. In Comparative Example 2, no hydrophobic flame retardant particles are added, and the number of washable times decreases. This is because the coating composition does not form a three-dimensional network structure with lithium silicate and does not play a role in hydrophobicity and coating stability; and because there is no hydrophobic group modification, the water resistance of the coating is poor, and the erosion resistance further decreases significantly.

[0109] In summary, for the inorganic water-resistant flame retardant material of the present invention, by using lithium silicate with a modulus of 4.5-10 as the main film-forming substance and combining the co-action of hydrophobic flame retardant particles and other raw materials, the water resistance and erosion resistance of the coating are effectively improved. Among them, it is possible to form a layered compound by using a magnesium salt compound and a titanium-containing compound, and fix the anions of phosphate in the interlayer. Moreover, titanium can be hydrophobically modified to prepare hydrophobic flame retardant particles, bind the phosphate anions to the layered structure of the hydrophobic flame retardant particles, and form a three-dimensional network structure with lithium silicate for the hydrophobic flame retardant particles, thereby chemically bonding each raw material, enhancing its compatibility and the strength of the coating. The problem of poor compatibility of the coating components when phosphate is added alone is overcome, enabling the building wall or building material to have better high-temperature resistance, waterproof, fireproof and other properties after using the coating of this application. Because the hydrophobicity and the compatibility of the components can reduce the coating damage and powdering caused by water wetting and erosion, the service life in a humid and rainy environment is greatly extended.

[0110] The above embodiments are only the preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention fall within the scope of protection required by the present invention.

Claims

1. An inorganic water-resistant flame-retardant coating, characterized in that: In parts by weight, it includes the following components: 25-40 parts of water, 5-35 parts of lithium water glass, 5-20 parts of hydrophobic flame retardant particles, 5-15 parts of jade powder, 5-8 parts of kaolin, 5-10 parts of heavy calcium, 1-4 parts of dispersant, 2-4 parts of thickener, 1-4 parts of defoamer; The preparation method of the hydrophobic flame retardant particles is: S31, adding triethoxyalkylsilane, titanate and hydrochloric acid to an ethanol solution to obtain a mixture; S32, adding magnesium salt and phosphate aqueous solution to the mixed solution obtained in step S31, stirring evenly, adjusting the pH and stirring the reaction, and completing the reaction to obtain the hydrophobic flame retardant particles; In the step S31, the alkyl group in the triethoxyalkylsilane is a C8-C18 branched chain or branched alkane; The molar ratio of triethoxyalkylsilane, titanate and hydrochloric acid is (0.5-1):1:(0.01-0.1); In step S32, the magnesium salt is magnesium chloride; the molar ratio of magnesium to titanate in the magnesium salt is (2.5-3.5):1; The phosphate is one or a combination of two or more of ammonium phosphate, sodium phosphate and potassium phosphate; the amount of the phosphate added is (0.2-0.5) of the molar amount of the titanate; In the step S32, after adjusting the pH to 10-11, the reaction is carried out at 60-80° C. for 3-10 hours; After the reaction in step S32 is completed, the reactants are aged at 50-70° C. for 5-24 hours, the solids are collected by centrifugation, and then wet-pulverized to obtain the hydrophobic flame-retardant particles.

2. The inorganic water-resistant flame-retardant coating according to claim 1, characterized in that: The invention comprises the following components in parts by weight: 25-35 parts of water, 10-30 parts of lithium water glass, 10-15 parts of hydrophobic flame retardant particles, 8-12 parts of jade powder, 6-7 parts of kaolin, 6-8 parts of heavy calcium, 2-3 parts of dispersant, 3-4 parts of thickener and 2-3 parts of defoaming agent.

3. An inorganic water-resistant flame-retardant coating according to claim 1 or 2, characterized in that: The titanate is tetrabutyl titanate, tetraisopropyl titanate or tetraethyl titanate.

4. The inorganic water-resistant flame-retardant coating according to claim 1, characterized in that: The molar ratio of SiO2 to Li2O in the lithium water glass is 4.5-10.

5. A method for preparing the inorganic water-resistant flame-retardant coating according to any one of claims 1 to 4, characterized in that: The following steps are involved: S11, pouring lithium water glass, hydrophobic flame retardant particles and jade powder into a stirring device for mixing and stirring, and adding water during stirring to obtain a mixed solution; S12, adding a defoamer, a thickener and a dispersant to the mixed solution prepared in S11, and continuing to stir to obtain a mixed coating; S13, after the mixed coating prepared in S12 has no obvious bubbles, add kaolin and heavy calcium, and continue stirring for 30-80 minutes to obtain the finished inorganic water-resistant flame retardant coating.

6. The method for preparing an inorganic water-resistant flame-retardant coating according to claim 5, characterized in that: The rotation speed of the stirring device is controlled at 200-400 r / min, and the stirring temperature is 20-30°C.

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