A highly weather-resistant inorganic exterior wall coating, its preparation method and application

Abstract

The present invention belongs to the technical field of building materials, and discloses a highly weather-resistant inorganic exterior wall coating, its preparation method and application. The highly weather-resistant inorganic exterior wall coating provided by the present invention comprises the following raw materials in parts by mass: 0.5-1.0 part of cellulose, 32-38 parts of silica sol, 8-10 parts of high-modulus potassium silicate, 10-20 parts of filler, 1-2.5 parts of stabilizer, 0.3-1.0 part of phosphonate complexing agent, 0.5-1.0 part of dispersant, 20-30 parts of pigment and 1.5-3.5 parts of auxiliary agent; the filler comprises magnesia powder and barium sulfate added in a mass ratio of (4-9):(7-12); the stabilizer comprises a silicate-silane stabilizer and a quaternary ammonium salt cationic stabilizer added in a mass ratio of (1-2.5):1. The highly weather-resistant inorganic exterior wall coating has good stability, washability, acid and alkali resistance, water resistance, temperature change resistance and artificial weathering resistance, and has excellent storage performance and weather resistance, and can be well applied to scenarios with high weather resistance requirements such as road and bridge projects, chemical factory buildings and tunnels.

Description

Technical Field

[0001] The present invention belongs to the technical field of building materials, and in particular relates to a highly weather-resistant inorganic exterior wall coating and its preparation method and application. Background Art

[0002] Inorganic exterior wall coatings refer to exterior wall coatings mainly using inorganic materials such as silica sol and alkali metal silicates as main binders. They have advantages such as simple operation and no pollution to the environment, and have been widely promoted. Currently, in order to make inorganic exterior wall coatings have better storage stability performance, calcium carbonate (light calcium carbonate or heavy calcium carbonate) is selected as a filler, which makes the weather resistance of exterior wall inorganic coatings relatively poor, and problems such as shrinkage cracking, powdering, and peeling are likely to occur, and they cannot be well applied in some environments with high acid resistance requirements such as road and bridge projects, chemical factories, tunnels, etc., and have great limitations. Summary of the Invention

[0003] In order to improve the weather resistance of inorganic exterior wall coatings, the present invention provides a highly weather-resistant inorganic exterior wall coating and its preparation method and application.

[0004] In the first aspect, a highly weather-resistant inorganic exterior wall coating provided by the present invention adopts the following technical solutions:

[0005] A highly weather-resistant inorganic exterior wall coating, comprising the following raw materials in parts by mass:

[0006] 0.5 - 1.0 parts of cellulose, 32 - 38 parts of silica sol, 8 - 10 parts of high-modulus potassium silicate, 10 - 20 parts of filler, 1 - 2.5 parts of stabilizer, 0.3 - 1.0 part of phosphonate complexing agent, 0.5 - 1.0 part of dispersant, 20 - 30 parts of pigment, and 1.5 - 3.5 parts of auxiliary agent;

[0007] The filler includes magnesium strong powder and barium sulfate, and the added mass ratio of magnesium strong powder to barium sulfate is (4 - 9)∶(7 - 12); the stabilizer includes a silicate silane stabilizer and a quaternary ammonium salt cation stabilizer, and the added mass ratio of the silicate silane stabilizer to the quaternary ammonium salt cation stabilizer is (1 - 2.5)∶1.

[0008] In the second aspect, a preparation method of a highly weather-resistant inorganic exterior wall coating provided by the present invention adopts the following technical solutions:

[0009] The preparation method of the highly weather-resistant inorganic exterior wall coating is specifically as follows:

[0010] (1) Completely dissolve cellulose in water, add a dispersant, a filler, a pigment and a part of the auxiliaries and mix them evenly to obtain a slurry. Add a phosphonate complexing agent to the slurry and mix evenly to obtain a stabilized slurry; mix silica sol with a silicate silane stabilizer evenly to obtain a stabilized silica sol solution; mix high-modulus potassium silicate with a quaternary ammonium salt cation stabilizer evenly to obtain a stabilized potassium silicate solution.

[0011] (2) Mix the stabilized silica sol solution, the stabilized potassium silicate solution and the stabilized slurry evenly, add the other part of the auxiliaries, and mix evenly to obtain the high weather resistance inorganic exterior wall coating.

[0012] In a third aspect, the present invention also provides the application of the above high weather resistance inorganic exterior wall coating in an environment with high acid resistance requirements.

[0013] Beneficial effects:

[0014] In the present invention, magnesium strong powder and barium sulfate are compounded in a certain proportion as the main components of the filler, a silicate silane stabilizer and a quaternary ammonium salt cation stabilizer are compounded in a certain proportion as the stabilizer, high-modulus potassium silicate and silica sol are used together as the binder, and cellulose is used as the film-forming substance. A phosphonate complexing agent is creatively added and combined with the auxiliaries commonly used in inorganic exterior wall coatings. The prepared inorganic exterior wall coating has good stability, washability, acid and alkali resistance, water resistance, temperature change resistance and artificial weather aging resistance. The storage performance and weather resistance are very excellent, and it can be well applied to scenarios with high weather resistance requirements such as road and bridge projects, chemical factory buildings and tunnels.

[0015] Although the inorganic exterior wall coating provided by the present invention does not contain a high molecular polymer, it has weather resistance equivalent to or even better than that of the exterior wall coating added with a high molecular polymer. The specific reasons are as follows: First, by mixing high-modulus potassium silicate, silica sol, magnesium strong powder, and barium sulfate, the amorphous silica contained in the silica sol reacts with the magnesium (elemental, ionic) contained in the magnesium strong powder and the barium (elemental, ionic) contained in the barium sulfate to generate magnesium silicate hydrate and barium silicate hydrate, which can coat the surface of the magnesium strong powder particles and the surface of the barium sulfate; Second, the phosphonate complexing agent can complex with multiple magnesium ions and barium ions; Third, the added quaternary ammonium salt cation stabilizer and the phosphonate complexing agent cooperate synergistically to play a bridging role among the silica sol, high-modulus potassium silicate, magnesium strong powder, and barium sulfate. At the same time, the addition of the silicate stabilizer can prevent the coagulation caused by the reaction of the quaternary ammonium salt cation stabilizer and the phosphonate complexing agent with the silica sol, high-modulus potassium silicate, magnesium silicate hydrate, barium silicate hydrate, and other substances; Through the synergistic cooperation and common action of the above reagents, a stable and uniform colloidal system is obtained. The colloidal particles in the colloidal system are macromolecular network complexes containing multiple monomer structures. When the colloidal system is placed in the air, the water in the system evaporates, and part of the magnesium silicate hydrate and barium silicate hydrate are precipitated, and a spatial barium-magnesium-silicon-oxygen network structure with the macromolecular network complex containing multiple monomer structures as the main repeating unit and interspersed with cellulose is formed. The spatial barium-magnesium-silicon-oxygen network structure can still remain stable under water, alkaline reagents, acidic reagents, large temperature changes, and mechanical destructive forces, thereby endowing the inorganic exterior wall coating with good weather resistance and storage performance. Detailed implementation mode

[0016] The high weather-resistant inorganic exterior wall coating provided by the present invention comprises cellulose, silica sol, potassium silicate with high modulus, filler, stabilizer, phosphonate complexing agent, dispersant, pigment and auxiliary agent; the content of the cellulose is 0.5 to 1.0 part by mass, such as 0.5, 0.6, 0.7, 0.8, 0.9, 1.0 part by mass or any value between them; the content of the silica sol is 32 to 38 parts by mass, such as 32, 33, 34, 35, 36, 37, 38 parts by mass or any value between them; the content of the potassium silicate with high modulus is 8 to 10 parts by mass, such as 8, 8.5, 9, 9.5, 10 parts by mass or any value between them; the content of the filler is 10 to 20 parts by mass, such as 10, 12, 14, 15, 18, 20 parts by mass or any value between them; the content of the stabilizer is 1 to 2.5 parts by mass, such as 1, 1.3, 1.5, 2.0, 2.2, 2.5 parts by mass or any value between them; the content of the phosphonate complexing agent is 0.3 to 1.0 part by mass, such as 0.3, 0.5, 0.6, 0.8, 1.0 part by mass or any value between them; the content of the dispersant is 0.5 to 1.0 part by mass, such as 0.5, 0.6, 0.7, 0.8, 0.9, 1.0 part by mass or any value between them; the content of the pigment is 20 to 30 parts by mass, such as 20, 22, 24, 26, 27, 29, 30 parts by mass or any value between them; the content of the auxiliary agent is 1.5 to 3.5 parts by mass, such as 1.5, 1.8, 2.0, 2.3, 2.5, 3.0, 3.2, 3.5 parts by mass or any value between them.

[0017] In the present invention, the filler comprises magnesium strong powder and barium sulfate, and the added mass ratio of the magnesium strong powder to the barium sulfate is (4 to 9)∶(7 to 12), such as 4∶7, 4∶9, 4∶11, 1∶3, 5∶7, 5∶12, 9∶7, 9∶10, 9∶11, 3∶4 or any value between them.

[0018] In the present invention, the stabilizer comprises silicate silane stabilizer and quaternary ammonium salt cation stabilizer, and the added mass ratio of the silicate silane stabilizer to the quaternary ammonium salt cation stabilizer is (1 to 2.5):1, such as 1∶1, 1.2∶1, 1.5∶1, 2.0∶1, 2.5∶1 or any value between them.

[0019] In the present invention, the magnesium strong powder has good acid and alkali corrosion resistance performance, excellent hydrophobic performance and suspension performance, and cooperates with barium sulfate, stabilizer and phosphonate complexing agent to endow the high weather-resistant inorganic exterior wall coating with excellent weather resistance and storage stability at the same time.

[0020] In some specific embodiments, the particle size of the magnesium strong powder is preferably 1,500 - 2,000 mesh, such as 1,500 mesh, 1,800 mesh, 1,900 mesh, 2,000 mesh or any value therebetween.

[0021] In the present invention, the barium sulfate has good acid resistance, and can improve the film hardness of the high weather resistance inorganic exterior wall coating to improve the scrub resistance. Cooperating with the magnesium strong powder, the stabilizer and the phosphonate complexing agent, it endows the high weather resistance inorganic exterior wall coating with good film hardness and scrub resistance.

[0022] In some specific embodiments, the particle size of the barium sulfate is preferably 500 - 800 mesh, such as 500 mesh, 550 mesh, 600 mesh, 650 mesh, 700 mesh, 800 mesh or any value therebetween.

[0023] In some specific embodiments, the content of the magnesium strong powder in the filler is preferably 4 - 8.5 parts by mass, such as 4, 4.5, 5, 6, 7.5, 8, 8.5 parts by mass or any value therebetween; the content of the barium sulfate is preferably 7 - 11 parts by mass, such as 7, 7.5, 8, 9, 10, 11 parts by mass or any value therebetween. At this time, a more ideal spatial barium-magnesium-silicon oxygen network structure can be obtained, thereby endowing the high weather resistance inorganic exterior wall coating with better weather resistance.

[0024] In the present invention, the silicate silane stabilizer can form a stable compound with silica sol and high-modulus potassium silicate, and cooperate synergistically with the quaternary ammonium salt cation stabilizer and the phosphonate complexing agent to effectively prevent the inorganic exterior wall coating from coagulating and settling, so as to endow the inorganic exterior wall coating with better storage stability.

[0025] In the present invention, the quaternary ammonium salt cation stabilizer is a kind of substance with multiple cation functional groups that blocks the gelling reaction between potassium silicate and high-valent metal cations, and cooperates synergistically with the silicate silane stabilizer and the phosphonate complexing agent to ensure the stability of the high weather resistance inorganic exterior wall coating during the storage period.

[0026] In some specific embodiments, the content of the silicate silane stabilizer in the stabilizer is preferably 0.5 - 1.2 parts by mass, such as 0.5, 0.6, 0.7, 0.9, 1.0, 1.2 parts by mass or any value therebetween; the content of the quaternary ammonium salt cation stabilizer is preferably 0.5 - 1.2 parts by mass, such as 0.5, 0.6, 0.8, 0.9, 1.1, 1.2 parts by mass or any value therebetween. At this time, better stabilizing and bridging effects can be provided, thereby endowing the high weather resistance inorganic exterior wall coating with more excellent weather resistance and storage stability.

[0027] In the present invention, the phosphonate complexing agent dissociates into positive and negative ions after being dissolved in water, and can complex with multiple metal ions, cooperate synergistically with cellulose, silica sol, magnesium powder, and barium sulfate to form a good spatial barium-magnesium-silicon-oxygen network structure, thereby endowing the high weather-resistant inorganic exterior wall coating with good weather resistance, and cooperate synergistically with the stabilizer to effectively prevent the high-modulus potassium silicate from coagulating with other components, thereby endowing the high weather-resistant inorganic exterior wall coating with good storage stability.

[0028] In some specific embodiments, the phosphonate complexing agent may specifically be, but is not limited to, one or more of sodium ethylene diamine tetra(methylene phosphonate), diethylenetriamine penta(methylene phosphonate), and amine trimethylene phosphate.

[0029] In some specific embodiments, the cellulose is specifically unmodified natural cellulose and / or cellulose ether. Among them, cellulose ether is a class of compounds obtained by chemical modification of natural cellulose, and exemplary ones may be, but are not limited to, one or more of methyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose, and carboxymethyl cellulose.

[0030] In some specific embodiments, the silica sol is preferably an inorganic nano-silicon modified silica sol, which contains abundant charges and high spatial dimensional stability, can obtain a more ideal spatial barium-magnesium-silicon-oxygen network structure, thereby endowing the high weather-resistant inorganic exterior wall coating with better weather resistance.

[0031] In the present invention, the modulus refers to the molar ratio of SiO2 and K2O contained in potassium silicate, and high-modulus potassium silicate is defined as potassium silicate with a modulus greater than 3.5. In some specific embodiments, the modulus of the high-modulus potassium silicate is preferably 3.8 to 4.8, such as 3.8, 3.9, 4.2, 4.5, 4.8 or any value between them; at this time, it can endow the high weather-resistant inorganic exterior wall coating with higher bonding strength, water resistance, and washability.

[0032] In the present invention, the dispersant is preferably a hydrophobic modified acrylic copolymer potassium salt dispersant, which has a good dispersing effect on barium sulfate and magnesium powder, and can endow the high weather-resistant inorganic exterior wall coating with excellent hydrophobic properties.

[0033] In the present invention, the pigment can be selected according to the color of the high weather-resistant inorganic exterior wall coating to be obtained, and specifically may be, but is not limited to, one or more of titanium dioxide, calcined kaolin, iron oxide yellow, ultramarine, chromium oxide green, and iron oxide red.

[0034] In some specific embodiments, the pigments are preferably titanium dioxide and calcined kaolin. The titanium dioxide is rutile titanium dioxide. The calcined kaolin refers to a kind of substance obtained by taking soft kaolin as raw material and removing crystal water, carbonaceous matter and other volatile substances through calcination processing. At this time, using titanium dioxide and calcined kaolin as pigments can endow the high weather resistance inorganic exterior wall coating with good coloring effect, and can cooperate with substances such as magnesium strong powder and barium sulfate to endow the high weather resistance inorganic exterior wall coating with more excellent weather resistance performance.

[0035] In the present invention, the additives may include wetting agents, water repellents, defoamers, mildew and algae inhibitors, and leveling agents. Among them, the content of the wetting agent can be 0.2 - 0.4 parts by mass, such as 0.2, 0.25, 0.3, 0.4 parts by mass or any value between them; the content of the water repellent can be 0.7 - 0.9 parts by mass, such as 0.7, 0.8, 0.85, 0.9 parts by mass or any value between them; the content of the defoamer can be 0.2 - 0.6 parts by mass, such as 0.2, 0.3, 0.4, 0.5, 0.6 parts by mass or any value between them; the content of the mildew and algae inhibitor can be 0.6 - 0.9 parts by mass, such as 0.6, 0.65, 0.7, 0.8, 0.9 parts by mass or any value between them; the content of the leveling agent can be 0.2 - 0.5 parts by mass, such as 0.2, 0.3, 0.4, 0.5 parts by mass or any value between them.

[0036] In some specific embodiments, the wetting agent is preferably a polyether silicone wetting agent, which has excellent substrate wetting property, and can reduce the surface tension of the high weather resistance inorganic exterior wall coating after film formation and prevent shrinkage pores, endowing the high weather resistance inorganic exterior wall coating with good film formation performance and weather resistance performance.

[0037] In some specific embodiments, the water repellent is preferably a silane water repellent, which has good compatibility with film-forming substances, binders and other substances of the high weather resistance inorganic exterior wall coating, and can act synergistically to endow the high weather resistance inorganic exterior wall coating with better water repellent performance.

[0038] In some specific embodiments, the defoamer is preferably an organosilicon defoamer, which has good defoaming effect, reduces the bubbles formed in the product due to gas mixing during the production process, and endows the high weather resistance inorganic exterior wall coating with better quality.

[0039] In some specific embodiments, the mildew and algae inhibitor is preferably one or more of n-octyl isothiazolinone, imidazole derivatives and arylurea derivatives, endowing the high weather resistance inorganic exterior wall coating with mildew and algae resistance performance, so that it can be better applied to environments prone to mildew and algae growth.

[0040] In some specific embodiments, the leveling agent is preferably a polyether-modified silicone compound, which can promote the formation of a flat, smooth and uniform film during the drying and film-forming process of the high-weather-resistant inorganic exterior wall coating.

[0041] The preparation method of the high-weather-resistant inorganic exterior wall coating provided by the present invention is specifically as follows:

[0042] (1) Completely dissolve cellulose in water, add a dispersant, a filler, a pigment and a part of the additives and mix evenly to obtain a slurry. Add a phosphonate complexing agent to the slurry and mix evenly to obtain a stabilized slurry; Mix silica sol and a silicate-silane stabilizer evenly to obtain a stabilized silica sol solution; Mix high-modulus potassium silicate and a quaternary ammonium salt cation stabilizer evenly to obtain a stabilized potassium silicate solution.

[0043] (2) Mix the stabilized silica sol solution, the stabilized potassium silicate solution and the stabilized slurry evenly, add the other part of the additives, and mix evenly to obtain the high-weather-resistant inorganic exterior wall coating.

[0044] In the present invention, in step (1), there is no particular limitation on the preparation sequence of the stabilized slurry, the stabilized silica sol solution and the stabilized potassium silicate solution. It can be the sequence of preparation one after another or the sequence of simultaneous preparation.

[0045] The present invention also provides the application of the above high-weather-resistant inorganic exterior wall coating in an environment with high weather resistance requirements. In some specific embodiments, the environment with high weather resistance requirements can specifically be, but is not limited to, environments such as road and bridge projects, chemical factory buildings, tunnels, etc.

[0046] The embodiments of the present invention are described in detail below. The examples are intended to explain the present invention and should not be construed as a limitation of the present invention. For those without specific technical or conditions noted in the examples, the techniques or conditions described in the literature in the art are followed or the product specifications are followed. For the reagents or instruments without the manufacturer noted, they are all conventional products that can be obtained through commercial purchase.

[0047] The reagents and their sources used in the following examples are specifically as follows:

[0048] Hydroxyethyl cellulose (Ashland, grade 250HBR); Dispersant (Arkema, grade Coadis 123K); Wetting agent (BYK Chemie, grade BYK346); Organosilicon defoamer (Hengxin Chemical Industry, grade THIX-278); Titanium dioxide (Shandong Dawn Titanium Industry, grade R-2195); Calcined kaolin (Yangzhou Dilan Chemical Industry); Colloidal silica (Heye Chemical Industry, grade WJ-8801); Silicate silane stabilizer (Sida Chemical, grade STAR GW150); High modulus potassium silicate (Aohan Chemical Industry, grade AH-K72); Quaternary ammonium salt cationic stabilizer (Aohan Chemical Industry, grade ST); Hydrophobic agent (Aohan Chemical Industry, grade SC-010); Antimildew agent (Hoffmann Chemical, grade Defros M3); Leveling agent (Hairun Chemical Industry, grade TU2991); Commercially available alkali-resistant acrylic emulsion (manufacturer: Badfu, grade RS837A).

[0049] Example 1

[0050] This example is used to illustrate the preparation of inorganic exterior wall coatings, which specifically includes the following steps:

[0051] (1) Preparation of stabilized slurry, stabilized colloidal silica solution and stabilized potassium silicate solution:

[0052] S1. Preparation of stabilized slurry: Add 11 parts of water to the pre-dispersion tank, and slowly add 0.5 part of hydroxyethyl cellulose while stirring at a speed of 800 r / min, and disperse for 10 min until completely dissolved without agglomerates; then sequentially add 0.8 part of dispersant, 0.4 part of wetting agent and 0.2 part of organosilicon defoamer, and continue stirring for 5 min; subsequently, sequentially add 15 parts of titanium dioxide, 8.5 parts of magnesium strong powder (particle size of 2000 mesh), 9 parts of calcined kaolin (particle size of 1250 - 3000 mesh) and 11 parts of barium sulfate (particle size of 800 mesh). After the feeding is completed, scrape the tank wall clean, and increase the stirring speed to 1500 r / min and disperse for 20 min to obtain a slurry with a fineness ≤ 60 μm; while stirring at a speed of 800 r / min, add 0.8 part of ethylenediaminetetra(methylene phosphonic acid) sodium to the slurry and disperse for 10 min to obtain a stabilized slurry.

[0053] S2. Preparation of stabilized colloidal silica solution: Add 32 parts of colloidal silica to the production tank, and add 0.5 part of silicate silane stabilizer while stirring at a speed of 800 r / min, and disperse for 10 min until in a homogeneous state to obtain a stabilized colloidal silica solution.

[0054] S3. Preparation of stabilized potassium silicate solution: Take 8 parts of high-modulus potassium silicate (modulus 4.2) and add it to the production tank. Under stirring at a speed of 800 r / min, add 0.5 part of quaternary ammonium salt cation stabilizer and disperse for 10 min until it reaches a homogeneous state, obtaining the stabilized potassium silicate solution.

[0055] (2) Preparation of inorganic exterior wall coating:

[0056] Under stirring at a speed of 800 r / min, add the stabilized silica gel solution to the stabilized slurry and disperse for 5 min until it reaches a homogeneous state. Then add the stabilized potassium silicate solution and disperse for 5 min until it reaches a homogeneous state. Subsequently, add 0.7 part of water repellent, 0.6 part of mildew preventive, and 0.5 part of leveling agent in sequence, and disperse for 10 min until it reaches a homogeneous state under a stirring speed of 600 r / min, obtaining the inorganic exterior wall coating.

[0057] Example 2

[0058] This example is used to illustrate the preparation of the inorganic exterior wall coating, which specifically includes the following steps:

[0059] (1) Preparation of stabilized slurry, stabilized silica sol solution, and stabilized potassium silicate solution:

[0060] S1. Preparation of stabilized slurry: Take 10 parts of water and add it to the pre-dispersion tank. Under stirring at a speed of 800 r / min, slowly add 0.6 part of hydroxyethyl cellulose and disperse for 15 min until it is completely dissolved without agglomerates. Then add 0.7 part of dispersant, 0.3 part of wetting agent, and 0.4 part of silicone defoamer in sequence and continue stirring for 5 min. Subsequently, add 18 parts of titanium dioxide, 5.6 parts of magnesium-strengthened powder, 8 parts of calcined kaolin (particle size 1250 - 3000 mesh), and 8 parts of barium sulfate (particle size 800 mesh). After feeding, scrape the tank wall clean and increase the stirring speed to 1500 r / min and disperse for 30 min to obtain a slurry with a fineness ≤ 60 μm. Under stirring at a speed of 800 r / min, add 0.5 part of ethylenediamine tetra(methylene phosphonic acid) sodium to the slurry and disperse for 15 min, obtaining the stabilized slurry.

[0061] S2. Preparation of stabilized silica sol solution: Take 34 parts of silica sol and add it to the production tank. Under stirring at a speed of 800 r / min, add 1 part of silicate silane stabilizer and disperse for 15 min until it reaches a homogeneous state, obtaining the stabilized silica sol solution.

[0062] S3. Preparation of stabilized potassium silicate solution: Take 10 parts of high-modulus potassium silicate (modulus 4.2) and add it to the production tank. Under stirring at a speed of 800 r / min, add 1 part of quaternary ammonium salt cation stabilizer and disperse for 15 min until it reaches a homogeneous state, obtaining the stabilized potassium silicate solution.

[0063] (2) Preparation of inorganic exterior wall coating: Under stirring at a speed of 800 r / min, add a stabilized silica sol solution to the stabilized slurry, disperse for 10 min until a uniform state is reached, and then add a stabilized potassium silicate solution, disperse for 10 min until a uniform state is reached; subsequently, add 0.8 parts of a water repellent, 0.8 parts of a mildew preventive, and 0.3 parts of a leveling agent in sequence, and disperse for 5 min until a uniform state is reached under a stirring speed of 600 r / min to obtain an inorganic exterior wall coating.

[0064] Example 3

[0065] This example is used to illustrate the preparation of an inorganic exterior wall coating, which specifically includes the following steps:

[0066] (1) Preparation of stabilized slurry, stabilized silica sol solution, and stabilized potassium silicate solution:

[0067] S1. Preparation of stabilized slurry: Take 9 parts of water and add it to a pre-dispersion tank, and under stirring at a speed of 800 r / min, slowly add 0.7 parts of hydroxyethyl cellulose, disperse for 12 min until completely dissolved without agglomerates; then add 0.6 parts of a dispersant, 0.2 parts of a wetting agent, and 0.6 parts of an organosilicon defoamer in sequence, and continue stirring for 5 min; subsequently, add 20 parts of titanium dioxide, 4 parts of magnesium strong powder (particle size of 2000 mesh), 6.2 parts of calcined kaolin (particle size of 1250 - 3000 mesh), and 7 parts of barium sulfate (particle size of 800 mesh) in sequence. After the feeding is completed, scrape the tank wall clean, and increase the stirring speed to 1500 r / min, disperse for 25 min to obtain a slurry with a fineness ≤ 60 μm; under stirring at a speed of 800 r / min, add 0.3 parts of ethylenediaminetetra(methylene phosphonic acid) sodium to the slurry, disperse for 12 min to obtain a stabilized slurry.

[0068] S2. Preparation of stabilized silica sol solution: Take 36 parts of silica sol and add it to a production tank, and under stirring at a speed of 800 r / min, add 1.2 parts of a silicate silane stabilizer, disperse for 12 min until a uniform state is reached to obtain a stabilized silica sol solution.

[0069] S3. Preparation of stabilized potassium silicate solution: Take 11 parts of high-modulus potassium silicate (modulus of 4.2) and add it to a production tank, and under stirring at a speed of 800 r / min, add 1.2 parts of a quaternary ammonium salt cationic stabilizer, disperse for 12 min until a uniform state is reached to obtain a stabilized potassium silicate solution.

[0070] (2) Preparation of inorganic exterior wall coating: Under stirring at a speed of 800 r / min, add a stabilized silica gel solution to the stabilized slurry, disperse for 12 min until a uniform state is achieved, then add a stabilized potassium silicate solution and disperse for 12 min until a uniform state; subsequently, add 0.9 parts of a water repellent, 0.9 parts of a mildew preventive, and 0.2 parts of a leveling agent in sequence, and disperse for 8 min until a uniform state is achieved under a stirring speed of 600 r / min to obtain the inorganic exterior wall coating.

[0071] Comparative Example 1

[0072] The inorganic exterior wall coating was prepared according to the method provided in Example 1, except that in step S1, barium sulfate (particle size of 800 mesh) was replaced with magnesium strong powder (particle size of 2000 mesh) in equal mass parts, and other conditions were the same.

[0073] Comparative Example 2

[0074] The inorganic exterior wall coating was prepared according to the method provided in Example 1, except that in step S1, magnesium strong powder (particle size of 2000 mesh) was replaced with barium sulfate (particle size of 800 mesh) in equal mass parts, and other conditions were the same.

[0075] Comparative Example 3

[0076] The inorganic exterior wall coating was prepared according to the method provided in Example 1, except that in step S1, heavy calcium carbonate (1500 mesh) was used to replace magnesium strong powder (2000 mesh) in equal mass parts, and heavy calcium carbonate (800 mesh) was used to replace barium sulfate (800 mesh) in equal mass; in step S3, a commercially available alkali-resistant acrylic emulsion was used to replace high-modulus potassium silicate, and a commercially available alkali-resistant acrylic emulsion was used to replace the quaternary ammonium salt cation stabilizer in equal mass parts, and other conditions were the same.

[0077] Comparative Example 4

[0078] The inorganic exterior wall coating was prepared according to the method provided in Example 1, except that in step S3, low-modulus potassium silicate (modulus of 2.0) was used to replace high-modulus potassium silicate (modulus of 4.2) in equal mass, and other conditions were the same.

[0079] Comparative Example 5

[0080] The inorganic exterior wall coating was prepared according to the method provided in Example 2, except that in step S1, water was used to replace ethylenediaminetetra(methylene phosphonic acid) sodium in equal mass, and other conditions were the same.

[0081] Comparative Example 6

[0082] This comparative example is used to illustrate the preparation of the inorganic exterior wall coating, which specifically includes the following steps:

[0083] S1. Preparation of stabilized slurry: Add 9 parts of water into the pre-dispersion tank, and slowly add 0.7 part of hydroxyethyl cellulose while stirring at a speed of 800 r / min. Disperse for 12 min until completely dissolved without agglomerates. Then, sequentially add 0.6 part of dispersant, 0.2 part of wetting agent, and 0.6 part of silicone defoamer, and continue stirring for 5 min. Subsequently, sequentially add 20 parts of titanium dioxide, 4 parts of magnesium strong powder (2000 mesh), 6.2 parts of calcined kaolin (1250 - 3000 mesh), and 7 parts of barium sulfate (800 mesh). After the feeding is completed, scrape the tank wall clean, and increase the stirring speed to 1500 r / min. Disperse for 25 min to obtain a slurry with a fineness ≤ 60 μm. While stirring at a speed of 800 r / min, add 0.3 part of sodium ethylene diamine tetra (methylene phosphonate) to the slurry and disperse for 12 min to obtain the stabilized slurry.

[0084] S2. Preparation of silica sol slurry: Add 37.2 parts of silica sol to the stabilized slurry, and disperse for 12 min until homogeneous while stirring at a speed of 800 r / min to obtain the silica sol slurry.

[0085] S3. Preparation of potassium silicate slurry: Add 12.2 parts of high-modulus potassium silicate (modulus 4.2) to the silica sol slurry, and disperse for 12 min until homogeneous while stirring at a speed of 800 r / min to obtain the potassium silicate slurry.

[0086] S4. Preparation of inorganic exterior wall coating: Sequentially add 0.9 part of water repellent, 0.9 part of mildew preventive, and 0.2 part of leveling agent to the potassium silicate slurry, and disperse for 8 min until homogeneous while stirring at a speed of 600 r / min to obtain the inorganic exterior wall coating.

[0087] Test Example

[0088] The following method is used to conduct relevant performance tests on the inorganic exterior wall coatings provided in Examples 1 - 3 and Comparative Examples 1 - 6, specifically as follows:

[0089] 1. Evaluate the combustion performance classification of the inorganic exterior wall coating according to the regulations of Class A1 combustion performance of flat building materials and products in GB 8624 - 2012 Classification of the Burning Behavior of Building Materials and Products;

[0090] 2. Evaluate the VOC content of the inorganic exterior wall coating according to the regulations of exterior wall coatings in GB 18582 - 2020 Limits of Hazardous Substances in Interior and Exterior Wall Coatings for Building Use;

[0091] 3. Evaluate the content of high molecular organic matter in the inorganic exterior wall coating according to the regulations of TCSTM00632.3 - 2022 Technical Requirements for Coating Products for Building Painting Works - Part 3: Inorganic Building Coating System;

[0092] 4. Evaluate the technical indicators of inorganic exterior wall coatings, such as the state in the container, workability, film appearance, thermal storage stability (30 d), low-temperature storage stability (3 times), surface drying time, contrast ratio, washability, alkali resistance (168 h), water resistance, temperature resistance variation, stain resistance, and artificial aging resistance, etc., in accordance with the provisions of JG / T 26-2002 "Inorganic Building Coatings for Exterior Walls".

[0093] 5. Evaluate the acid resistance and adhesion of inorganic exterior wall coatings in accordance with the provisions of Type II in JG / T 446-2014 "Luminous Coatings for Building Use". The test results are shown in Table 1.

[0094] It can be seen from the test results in Table 1 that, compared with Comparative Example 1, in Example 1 of the present invention, when using a compound of magnesia powder and barium sulfate as fillers instead of only adding magnesia powder, the two cooperate with other components to improve the washability, artificial weathering resistance and acid resistance of the inorganic exterior wall coating.

[0095] Compared with Comparative Example 2, in Example 1 of the present invention, when using a compound of magnesia powder and barium sulfate as fillers instead of only adding barium sulfate, the two cooperate with other components to improve the state in the container, thermal storage stability (30 d) and low-temperature storage stability of the inorganic exterior wall coating.

[0096] Compared with Comparative Example 3, in Example 1 of the present invention, the content of high-molecular organic matter in the inorganic exterior wall coating is 0.6% - 0.8% and the VOC content is 0.6 - 0.8%, which is much lower than that in Comparative Example 3 and meets the requirements of relevant international and domestic standards. At the same time, compared with the heavy calcium filler commonly used in traditional inorganic exterior wall coatings used in Comparative Example 3, using barium sulfate and magnesia powder as fillers in the present invention, the inorganic exterior wall coating has better acid resistance, artificial weathering resistance, adhesion, washability and stain resistance.

[0097] Compared with Comparative Example 4, in Example 1 of the present invention, when using potassium silicate with a high modulus instead of potassium silicate with a low modulus (modulus of 2.0), it can cooperate better with magnesia powder, barium sulfate and other substances in the inorganic exterior wall coating, so as to obtain an inorganic exterior wall coating with excellent washability, alkali resistance, water resistance, artificial weathering resistance, acid resistance and adhesion.

[0098] Compared with Comparative Example 5, in Example 2 of the present invention, the dispersion stability, workability, film-forming performance, thermal storage stability and low-temperature storage stability of the inorganic exterior wall coating are significantly better than those in Comparative Example 5, indicating that the use of barium sulfate and magnesia powder as fillers must be combined with a phosphonate complexing agent, otherwise the prepared inorganic exterior wall coating will lose its basic workability.

[0099] Compared with Comparative Example 6, the thermal storage stability and low-temperature storage stability of the inorganic exterior wall coating in Example 3 of the present invention are significantly better than those of Comparative Example 6; it shows that the introduction of silicate silane stabilizer and quaternary ammonium salt cation stabilizer can effectively solve the adverse effects brought by the common use of potassium silicate and silica sol on the storage stability of the inorganic exterior wall coating, thereby endowing the inorganic exterior wall coating with good storage stability.

[0100]

[0101] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention without departing from the principles and purposes of the present invention.

Claims

1. A highly weather-resistant inorganic exterior wall coating, characterized in that, It includes raw materials in the following parts by mass: 0.5 - 1.0 parts of cellulose, 32 - 38 parts of silica sol, 8 - 10 parts of high-modulus potassium silicate, 10 - 20 parts of filler, 1 - 2.5 parts of stabilizer, 0.3 - 1.0 part of phosphonate complexing agent, 0.5 - 1.0 part of dispersant, 20 - 30 parts of pigment, and 1.5 - 3.5 parts of auxiliary agent; The filler includes magnesium strong powder and barium sulfate, and the mass ratio of the added magnesium strong powder to barium sulfate is (4 - 9):(7 - 12); the stabilizer includes silicate silane stabilizer and quaternary ammonium salt cation stabilizer, and the mass ratio of the added silicate silane stabilizer to quaternary ammonium salt cation stabilizer is (1 - 2.5):1; The preparation of the high weather-resistant inorganic exterior wall coating includes: (1) Completely dissolve cellulose in water, add dispersant, filler, pigment, and a part of the auxiliary agent and mix evenly to obtain a slurry, add the phosphonate complexing agent to the slurry and mix evenly to obtain a stabilized slurry; Mix silica sol with silicate silane stabilizer evenly to obtain a stabilized silica sol solution; Mix high-modulus potassium silicate with quaternary ammonium salt cation stabilizer evenly to obtain a stabilized potassium silicate solution; (2) Mix the stabilized silica sol solution, the stabilized potassium silicate solution, and the stabilized slurry evenly, add the other part of the auxiliary agent, and mix evenly to obtain the high weather-resistant inorganic exterior wall coating.

2. The highly weather-resistant inorganic exterior wall coating according to claim 1, wherein The filler includes 4 - 8.5 parts of magnesium strong powder and 7 - 11 parts of barium sulfate.

3. The high weather resistance inorganic exterior wall coating according to claim 1, characterized in that, The particle size of the magnesium strong powder is 1500 - 2000 mesh; the particle size of the barium sulfate is 500 - 800 mesh.

4. The high weather resistance inorganic exterior wall coating according to claim 1, characterized in that, The stabilizer includes 0.5 - 1.2 parts of silicate silane stabilizer and 0.5 - 1.2 parts of quaternary ammonium salt cation stabilizer.

5. The highly weather-resistant inorganic exterior wall coating according to claim 1, characterized in that, The phosphonate complexing agent is selected from one or more of sodium ethylene diamine tetra(methylene phosphonate), diethylenetriamine penta(methylene phosphonate), and amine trimethylene phosphate.

6. The highly weather-resistant inorganic exterior wall coating according to claim 1, characterized in that, The dispersant is a potassium salt dispersant of a hydrophobic modified acrylic copolymer.

7. The high weather-resistant inorganic exterior wall coating according to claim 1, characterized in that, The pigment is selected from one or more of titanium dioxide, calcined kaolin, iron oxide yellow, ultramarine blue, chromium oxide green, and iron oxide red.

8. The high weather-resistant inorganic exterior wall coating according to claim 1, characterized in that, The auxiliary agent includes 0.2 - 0.4 part of wetting agent, 0.7 - 0.9 part of water repellent, 0.2 - 0.6 part of defoaming agent, 0.6 - 0.9 part of mildew and algae resistant agent, and 0.2 - 0.5 part of leveling agent.

9. The highly weather-resistant inorganic exterior wall coating according to claim 8, characterized in that, The wetting agent is a polyether siloxane wetting agent.

10. The highly weather-resistant inorganic exterior wall coating according to claim 8, characterized in that, The water repellent is a silane-based water repellent.

11. The highly weather-resistant inorganic exterior wall coating according to claim 8, wherein The defoaming agent is an organosilicon defoaming agent.

12. The highly weather-resistant inorganic exterior wall coating according to claim 8, wherein The mildew and algae resistant agent is selected from one or more of n-octyl isothiazolinone, imidazole derivatives, and aryl urea derivatives.

13. The high weather-resistant inorganic exterior wall coating according to claim 8, characterized in that, The leveling agent is a polyether-modified organosilicon compound.

14. The preparation method of the highly weather-resistant inorganic exterior wall coating according to any one of claims 1 to 13, characterized in that, The specific preparation method is as follows: (1) Completely dissolve cellulose in water, add dispersant, filler, pigment, and a part of the auxiliary agent and mix evenly to obtain a slurry, add the phosphonate complexing agent to the slurry and mix evenly to obtain a stabilized slurry; Mix silica sol with silicate silane stabilizer evenly to obtain a stabilized silica sol solution; Mix high-modulus potassium silicate with quaternary ammonium salt cation stabilizer evenly to obtain a stabilized potassium silicate solution; (2) Mix the stabilized silica sol solution, the stabilized potassium silicate solution and the stabilized slurry evenly, add another part of additives, and mix evenly to obtain the high weather-resistant inorganic exterior wall coating.

15. Application of the high weather-resistant inorganic exterior wall coating according to any one of claims 1 to 13 in an environment with high weather resistance requirements.

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