High performance inorganic coating and method for making same

Abstract

This invention relates to a high-performance inorganic coating and its preparation method, comprising, by weight: 20-25 parts water, 15-25 parts modified potassium silicate, 10-20 parts organic-inorganic hybrid nano-silica sol, 0.5-1.5 parts thickener, 0.5-1 part dispersant, 0.1-0.5 parts wetting agent, 0.5-1 part defoamer, 10-20 parts titanium dioxide, 5-20 parts barium sulfate, 5-20 parts heavy calcium carbonate, 2-5 parts calcined kaolin, 3-5 parts mica powder, 5-10 parts emulsion, and 0.5-1 part film-forming aid. This invention ensures the coating possesses certain washability and stability by using modified potassium silicate and silica sol as the main inorganic film-forming substances; simultaneously, the introduction of emulsion as an auxiliary film-forming substance greatly improves the number of washes and washability stability.

Description

Technical Field

[0001] This invention relates to the field of inorganic coating technology, and in particular to a high-performance inorganic coating and its preparation method. Background Technology

[0002] With the improvement of living standards, people have increasingly higher requirements for their home environment. Most architectural coatings on the market use organic polymer emulsions as film-forming substances. However, these coatings generally suffer from poor weather resistance, susceptibility to mold and mildew, aging, and flammability, and may also negatively impact indoor air quality. In contrast to organic coatings, inorganic coatings are directly derived from abundant minerals found in nature. Their production and application processes fully comply with energy conservation and emission reduction requirements, and they possess technical indicators that most organic coatings at the same cost cannot achieve. In recent years, the mandatory national requirements for fire-retardant and non-combustible coatings for underground enclosed spaces have driven the rapid development of inorganic coatings in the domestic construction market, providing a rare development opportunity for inorganic silicate coatings in my country.

[0003] Currently, inorganic coatings mainly use silicate-based film-forming substances. Due to their poor water resistance after film formation, relatively slow performance growth, and long curing cycles, their washability is often unsatisfactory. Most commercially available inorganic coatings completely fail after a few hundred to three or four thousand washes. Furthermore, the washability of commercially available inorganic coatings is highly unstable; some inorganic products that claim to pass the highest grade standards may only pass 6,000 washes, which is highly unpredictable. Therefore, for locations with high washability requirements, such as schools and hospitals, the requirements for the coatings used often far exceed the standards of conventional high-grade products, and existing inorganic coatings still cannot adequately meet these needs.

[0004] Given the numerous advantages of inorganic coatings, such as non-flammability and weather resistance, there is an urgent need to develop a new type of inorganic coating that is environmentally friendly, has excellent washability, and can meet the usage requirements of different environments. Summary of the Invention

[0005] The technical problem to be solved by the present invention is: the present invention provides a high-performance inorganic coating and its preparation method, which effectively solves the problems of poor scrub resistance and unstable scrub resistance of current inorganic coatings by introducing synthetic resin emulsion into the inorganic base material.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0007] In a first aspect, the present invention provides a high-performance inorganic coating, comprising, by weight:

[0008] Water 20-25 parts, modified potassium silicate 15-25 parts, organic-inorganic hybrid nano silica sol 10-20 parts, thickener 0.5-1.5 parts, dispersant 0.5-1 part, wetting agent 0.1-0.5 parts, defoamer 0.5-1 part, titanium dioxide 10-20 parts, barium sulfate 5-20 parts, heavy calcium carbonate 5-20 parts, calcined kaolin 2-5 parts, mica powder 3-5 parts, emulsion 5-10 parts, film-forming aid 0.5-1 part.

[0009] This invention proposes a high-performance inorganic coating that uses modified potassium silicate and silica sol as the main inorganic film-forming substances. Firstly, the modification treatment ensures the stability of the potassium silicate and silica sol themselves and the reaction system. Secondly, the combination of modified potassium silicate and organic-inorganic hybrid nano-silica sol can compensate for each other's shortcomings and form a Si-O-Si spatial network coating film, effectively improving the cracking phenomenon and poor early water resistance of the coating film, ensuring that the coating has certain wash resistance and stability. Simultaneously, an emulsion is introduced as an auxiliary film-forming substance, which can both fill the gaps in the Si-O-Si network structure and participate in the curing reaction together with the inorganic film-forming substances, thereby greatly improving the number of washes and the wash resistance stability.

[0010] Optionally, the modified potassium silicate is potassium silicate that has been chemically modified with quaternary ammonium salt and silane.

[0011] As described above, modifying potassium silicate with quaternary ammonium salts and silanes can inhibit the activity of potassium silicate, resulting in stabilized potassium silicate, thereby ensuring the stability of potassium silicate in the reaction system and preventing gel from coming out of the solution.

[0012] Optionally, the modulus of the modified potassium silicate is 2.8-5.0.

[0013] As described above, the modulus of the preferred modified potassium silicate solution ensures that the degree of polymerization, molecular weight, and viscosity of the silicate ions in the potassium silicate solution are moderate, which can reduce cracking and powdering while ensuring relatively improved water resistance of the coating film.

[0014] Optionally, the organic-inorganic hybrid nano-silica sol has a solid content of 28-32% and a pH of 9-11.

[0015] As described above, silica sol is a gel-like structure that is inherently unstable. However, this application uses organically modified silica sol, which can significantly improve its stability and thus enhance its film-forming properties.

[0016] Optionally, the emulsion is a mixture of styrene-acrylic emulsion and fluorocarbon emulsion.

[0017] As described above, the preferred combination of styrene-acrylic emulsion and fluorocarbon emulsion as an auxiliary film-forming substance exhibits good compatibility with modified potassium silicate and organic-inorganic hybrid nano-silica sol, significantly improving the film-forming properties, washability, and stability of the coating. In particular, the presence of the fluorocarbon emulsion further enhances the coating's water resistance, stain resistance, and washability, while also overcoming the poor storage stability problem inherent in conventional potassium silicate and styrene-acrylic emulsion blends.

[0018] Optionally, the fluorocarbon emulsion accounts for 5-30% of the total weight of the emulsion.

[0019] As can be seen from the above description, the optimal amount of fluorocarbon emulsion avoids the problem of easy cracking of the paint film when the content is too high and the problem of little benefit to the coating performance when the content is too low. The appropriate amount significantly improves the scrub resistance of the coating.

[0020] Optionally, the thickener is at least one selected from hydroxyethyl cellulose, attapulgite, polyurethane thickener, and alkali thickener;

[0021] The dispersant is at least one of sodium polycarboxylate dispersant and sodium polyacrylate dispersant;

[0022] The wetting agent is at least one of nonionic surfactant and anionic surfactant;

[0023] The defoamer is at least one of mineral oil defoamers and organosilicon defoamers;

[0024] The titanium dioxide is rutile titanium dioxide;

[0025] The barium sulfate is at least one of natural barium sulfate and precipitated barium sulfate.

[0026] Secondly, the present invention provides a method for preparing a high-performance inorganic coating, comprising the following steps:

[0027] S1. Add water to the dispersion tank and stir at the first stirring rate. Add some thickener and disperse for 5-10 minutes. Then add dispersant, wetting agent and defoamer and continue to disperse for 5 minutes.

[0028] S2. Adjust the speed to the second stirring rate, add titanium dioxide, barium sulfate, heavy calcium carbonate, calcined kaolin and mica powder, disperse for 15-20 minutes until the fineness is ≤50μm;

[0029] S3. Adjust the speed to the third stirring rate, add the emulsion, and stir for 5 minutes until the emulsion is evenly mixed;

[0030] S4. Finally, add the modified potassium silicate, organic-inorganic hybrid nano silica sol, film-forming aid and the remaining thickener in sequence, stir for 10-15 minutes until uniform, filter, and it is ready.

[0031] Optionally, the first stirring rate is 400-600 rpm; the second stirring rate is 1200-1500 rpm; and the third stirring rate is 700-1000 rpm.

[0032] This application employs a specific process sequence (adding the emulsion first, followed by the modified potassium silicate and the organic-inorganic hybrid nano-silica sol) to ensure that the emulsion is mixed uniformly and to minimize the impact on the subsequently added modified potassium silicate and organic-inorganic hybrid nano-silica sol, thereby further optimizing the scrub resistance of the coating. Furthermore, the preparation method provided in this application is simple to operate and facilitates industrial promotion and application. Detailed Implementation

[0033] To better understand the above technical solutions, exemplary embodiments of the present invention will be described in more detail below. While exemplary embodiments of the present invention are shown, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a clearer and more thorough understanding of the present invention and to fully convey the scope of the invention to those skilled in the art.

[0034] This embodiment provides a high-performance inorganic coating, comprising, by weight:

[0035] Water 20-25 parts, modified potassium silicate 15-25 parts, organic-inorganic hybrid nano silica sol 10-20 parts, thickener 0.5-1.5 parts, dispersant 0.5-1 part, wetting agent 0.1-0.5 parts, defoamer 0.5-1 part, titanium dioxide 10-20 parts, barium sulfate 5-20 parts, heavy calcium carbonate 5-20 parts, calcined kaolin 2-5 parts, mica powder 3-5 parts, emulsion 5-10 parts, film-forming aid 0.5-1 part.

[0036] The modified potassium silicate is potassium silicate that has been chemically modified with quaternary ammonium salt and silane.

[0037] A typical method for preparing modified potassium silicate includes the following steps: first, potassium silicate is modified with silane (the mass ratio of silane to potassium silicate is 0.005-0.015:1), and then the potassium silicate is further modified with quaternary ammonium salt (the mass ratio of quaternary ammonium salt to potassium silicate is 0.01-0.03:1) to obtain stabilized modified potassium silicate.

[0038] The modulus of the modified potassium silicate is 2.8-5.0.

[0039] The organic-inorganic hybrid nano-silica sol has a solid content of 28-32% and a pH of 9-11.

[0040] The emulsion is a mixture of styrene-acrylic emulsion and fluorocarbon emulsion.

[0041] The fluorocarbon emulsion accounts for 5-30% of the total weight of the emulsion.

[0042] The thickener is at least one of hydroxyethyl cellulose, attapulgite, polyurethane thickener and alkali thickener;

[0043] The dispersant is at least one of sodium polycarboxylate dispersant and sodium polyacrylate dispersant;

[0044] The wetting agent is at least one of nonionic surfactant and anionic surfactant;

[0045] The defoamer is at least one of mineral oil defoamers and organosilicon defoamers;

[0046] The titanium dioxide is rutile titanium dioxide;

[0047] The barium sulfate is at least one of natural barium sulfate and precipitated barium sulfate.

[0048] It is prepared by the following method, including the following steps:

[0049] S1. Add water to the dispersion tank and stir at 400-600 rpm. Add some thickener and disperse for 5-10 minutes. Then add dispersant, wetting agent and defoamer and continue to disperse for 5 minutes.

[0050] S2. Adjust the rotation speed to 1200-1500 rpm, add titanium dioxide, barium sulfate, heavy calcium carbonate, calcined kaolin and mica powder, disperse for 15-20 minutes until the fineness is ≤50μm;

[0051] S3. Adjust the speed to 700-1000 rpm, add the emulsion, and stir for 5 minutes until the emulsion is evenly mixed;

[0052] S4. Finally, add the modified potassium silicate, organic-inorganic hybrid nano silica sol, film-forming aid and the remaining thickener in sequence, stir for 10-15 minutes until uniform, filter, and it is ready.

[0053] Example 1

[0054] A high-performance inorganic coating, comprising, by weight:

[0055] 20.8 parts water, 20 parts modified potassium silicate, 10 parts organic-inorganic hybrid nano silica sol, 0.8 parts thickener (0.5 parts hydroxyethyl cellulose + 0.3 parts polyurethane thickener), 0.5 parts dispersant, 0.1 parts wetting agent, 0.8 parts defoamer, 14 parts titanium dioxide, 5 parts barium sulfate, 15 parts heavy calcium carbonate, 2 parts calcined kaolin, 5 parts mica powder, 5.5 parts emulsion (5 parts styrene-acrylic emulsion + 0.5 parts fluorocarbon emulsion), and 0.5 parts film-forming aid.

[0056] The modified potassium silicate is potassium silicate that has been chemically modified with quaternary ammonium salt and silane.

[0057] The method for preparing the modified potassium silicate includes the following steps: first, potassium silicate is modified with silane (the mass ratio of silane to potassium silicate is 0.005-0.015:1), and then the potassium silicate is further modified with quaternary ammonium salt (the mass ratio of quaternary ammonium salt to potassium silicate is 0.01-0.03:1) to obtain the stabilized modified potassium silicate.

[0058] The modulus of the modified potassium silicate is 2.8-5.0.

[0059] The organic-inorganic hybrid nano-silica sol has a solid content of 28-32% and a pH of 9-11.

[0060] The emulsion is a mixture of styrene-acrylic emulsion and fluorocarbon emulsion.

[0061] The fluorocarbon emulsion accounts for 9.1% of the total weight of the emulsion.

[0062] The thickener is a combination of hydroxyethyl cellulose and polyurethane thickener.

[0063] The dispersant is a sodium polycarboxylate dispersant;

[0064] The wetting agent is a nonionic surfactant;

[0065] The defoamer is a combination of mineral oil defoamer and organosilicon defoamer;

[0066] The titanium dioxide is rutile titanium dioxide;

[0067] The barium sulfate mentioned is precipitated barium sulfate.

[0068] It is prepared by the following method, including the following steps:

[0069] S1. Add water to the dispersion tank and stir at 400 rpm. Add some thickener (hydroxyethyl cellulose) and disperse for 5 minutes. Then add dispersant, wetting agent and defoamer and continue to disperse for 5 minutes.

[0070] S2. Adjust the rotation speed to 1300 rpm, add titanium dioxide, barium sulfate, heavy calcium carbonate, calcined kaolin and mica powder, disperse for 20 minutes until the fineness is ≤50μm;

[0071] S3. Adjust the speed to 800 rpm, add the emulsion, and stir for 5 minutes until the emulsion is evenly mixed;

[0072] S4. Finally, add the modified potassium silicate, organic-inorganic hybrid nano silica sol, film-forming aid and the remaining thickener (polyurethane thickener) in sequence, stir for 10 minutes until uniform, filter, and it is ready.

[0073] Example 2

[0074] The main difference between this embodiment and Embodiment 1 is that the amount of each component is different.

[0075] A high-performance inorganic coating, comprising, by weight:

[0076] 20.3 parts water, 20 parts modified potassium silicate, 10 parts organic-inorganic hybrid nano silica sol, 0.8 parts thickener (0.5 parts hydroxyethyl cellulose + 0.3 parts polyurethane thickener), 0.5 parts dispersant, 0.1 parts wetting agent, 0.8 parts defoamer, 14 parts titanium dioxide, 5 parts barium sulfate, 15 parts heavy calcium carbonate, 2 parts calcined kaolin, 5 parts mica powder, 6 parts emulsion (5 parts styrene-acrylic emulsion + 1 part fluorocarbon emulsion), and 0.5 parts film-forming aid.

[0077] Example 3

[0078] The main difference between this embodiment and Embodiment 1 is that the amount of each component is different.

[0079] A high-performance inorganic coating, comprising, by weight:

[0080] 19.3 parts water, 20 parts modified potassium silicate, 10 parts organic-inorganic hybrid nano silica sol, 0.8 parts thickener (0.5 parts hydroxyethyl cellulose + 0.3 parts polyurethane thickener), 0.5 parts dispersant, 0.1 parts wetting agent, 0.8 parts defoamer, 14 parts titanium dioxide, 5 parts barium sulfate, 15 parts heavy calcium carbonate, 2 parts calcined kaolin, 5 parts mica powder, 7 parts emulsion (5 parts styrene-acrylic emulsion + 2 parts fluorocarbon emulsion), and 0.5 parts film-forming aid.

[0081] Example 4

[0082] The main difference between this embodiment and Embodiment 3 is that the percentage of fluorocarbon emulsion in the total weight of the emulsion is different.

[0083] A high-performance inorganic coating, comprising, by weight:

[0084] 19.3 parts water, 20 parts modified potassium silicate, 10 parts organic-inorganic hybrid nano silica sol, 0.8 parts thickener (0.5 parts hydroxyethyl cellulose + 0.3 parts polyurethane thickener), 0.5 parts dispersant, 0.1 parts wetting agent, 0.8 parts defoamer, 14 parts titanium dioxide, 5 parts barium sulfate, 15 parts heavy calcium carbonate, 2 parts calcined kaolin, 5 parts mica powder, 7 parts emulsion (6.65 parts styrene-acrylic emulsion + 0.35 parts fluorocarbon emulsion), and 0.5 parts film-forming aid.

[0085] Comparative Example 1

[0086] The main difference between this comparative example and Example 3 is that an equal amount of modified potassium silicate is used to replace the organic-inorganic hybrid nano-silica sol, and an equal amount of styrene-acrylic emulsion is used to replace the fluorocarbon emulsion. That is, 30 parts of modified potassium silicate and 7 parts of styrene-acrylic emulsion are used as the film-forming system.

[0087] Comparative Example 2

[0088] The main difference between this comparative example and Example 3 is that an equal amount of organic-inorganic hybrid nano-silica sol is used to replace the modified potassium silicate, and an equal amount of styrene-acrylic emulsion is used to replace the fluorocarbon emulsion. That is, 30 parts of organic-inorganic hybrid nano-silica sol and 7 parts of styrene-acrylic emulsion are used as the film-forming system.

[0089] Comparative Example 3

[0090] The main difference between this comparative example and Example 3 is that an equal amount of styrene-acrylic emulsion is used instead of fluorocarbon emulsion. Specifically, 20 parts of modified potassium silicate, 10 parts of organic-inorganic hybrid nano-silica sol, and 7 parts of styrene-acrylic emulsion are used as the film-forming system.

[0091] Comparative Example 4

[0092] The main difference between this comparative example and Example 3 is that the percentage of fluorocarbon emulsion in the total weight of the emulsion is different (the percentage of fluorocarbon emulsion in the total weight of the emulsion is <5%), that is, 7 parts of emulsion are used (6.8 parts of styrene-acrylic emulsion + 0.2 parts of fluorocarbon emulsion).

[0093] Comparative Example 5

[0094] The main difference between this comparative example and Example 3 is that the percentage of fluorocarbon emulsion in the total weight of the emulsion is different (the percentage of fluorocarbon emulsion in the total weight of the emulsion is >30%), that is, 7 parts of emulsion are used (4 parts of styrene-acrylic emulsion + 3 parts of fluorocarbon emulsion).

[0095] Comparative Example 6

[0096] The main difference between this comparative example and Example 3 is the different process sequence. Specifically, the coating is prepared by first adding modified potassium silicate and organic-inorganic hybrid nano-silica sol, followed by adding emulsion.

[0097] The inorganic coatings prepared in Examples 1-4 and Comparative Examples 1-6 were subjected to performance tests, and the results are recorded in Table 1.

[0098] Table 1 Performance test results of inorganic coatings

[0099]

[0100]

[0101] As shown in Table 1, the high-performance inorganic coatings prepared in Examples 1-4 of this invention exhibit excellent storage stability, environmental friendliness, workability, scrub resistance, and scrub repeatability, making them widely applicable in various locations such as schools and hospitals. Comparative Example 1 uses only modified potassium silicate and styrene-acrylic emulsion as the film-forming system. Due to the large amount of modified potassium silicate added, the storage stability and scrub resistance of the coating are significantly reduced. Comparative Example 2 uses only organic-inorganic hybrid nano-silica sol and styrene-acrylic emulsion as the film-forming system. Due to the poor film-forming properties of silica sol, the scrub resistance of the coating is poor. Comparative Example 3 uses modified potassium silicate, organic-inorganic hybrid nano-silica sol, and styrene-acrylic emulsion as the film-forming system. Although its scrub resistance is improved compared to Comparative Examples 1 and 2, the lack of fluorocarbon emulsion still results in a certain degree of decrease in scrub resistance compared to Example 3. Comparative Example 4, due to its low proportion of fluorocarbon emulsion, had limited effect on improving the scrub resistance of the coating; while Comparative Example 5, due to its high proportion of fluorocarbon emulsion, although exhibiting good scrub resistance, was prone to cracking. Comparative Example 6, by using a sequence of adding modified potassium silicate and organic-inorganic hybrid nano-silica sol first, followed by the emulsion, also showed inferior scrub resistance compared to Example 3. This is attributed to the fact that continuously adding the emulsion under a highly alkaline environment easily leads to its degradation.

[0102] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-performance inorganic coating, comprising, by weight: Water 20-25 parts, modified potassium silicate 15-25 parts, organic-inorganic hybrid nano silica sol 10-20 parts, thickener 0.5-1.5 parts, dispersant 0.5-1 part, wetting agent 0.1-0.5 parts, defoamer 0.5-1 part, titanium dioxide 10-20 parts, barium sulfate 5-20 parts, heavy calcium carbonate 5-20 parts, calcined kaolin 2-5 parts, mica powder 3-5 parts, emulsion 5-10 parts, film-forming aid 0.5-1 part; The modified potassium silicate is potassium silicate that has been chemically modified with quaternary ammonium salt and silane; The emulsion is a mixture of styrene-acrylic emulsion and fluorocarbon emulsion; The fluorocarbon emulsion accounts for 9.1-30% of the total weight of the emulsion; The preparation method of the high-performance inorganic coating includes the following steps: S1. Add water to the dispersion tank and stir at the first stirring rate. Add some thickener and disperse for 5-10 minutes. Then add dispersant, wetting agent and defoamer and continue to disperse for 5 minutes. S2. Adjust the speed to the second stirring rate, add titanium dioxide, barium sulfate, heavy calcium carbonate, calcined kaolin and mica powder, disperse for 15-20 minutes until the fineness is ≤50μm; S3. Adjust the speed to the third stirring rate, add the emulsion, and stir for 5 minutes until the emulsion is evenly mixed; S4. Finally, add the modified potassium silicate, organic-inorganic hybrid nano silica sol, film-forming aid and the remaining thickener in sequence, stir for 10-15 minutes until uniform, filter, and it is ready.

2. The high performance inorganic coating of claim 1, wherein, The modulus of the modified potassium silicate is 2.8-5.

0.

3. The high-performance inorganic coating as described in claim 1, characterized in that, The organic-inorganic hybrid nano-silica sol has a solid content of 28-32% and a pH of 9-11.

4. The high-performance inorganic coating as described in claim 1, characterized in that, The thickener is at least one of hydroxyethyl cellulose, attapulgite, polyurethane thickener and alkali thickener; The dispersant is a sodium polycarboxylate dispersant; The wetting agent is at least one of nonionic surfactant and anionic surfactant; The defoamer is at least one of mineral oil defoamers and organosilicon defoamers; The titanium dioxide is rutile titanium dioxide; The barium sulfate is at least one of natural barium sulfate and precipitated barium sulfate.

5. The high-performance inorganic coating as described in claim 1, characterized in that, The first stirring rate is 400-600 rpm; the second stirring rate is 1200-1500 rpm; and the third stirring rate is 700-1000 rpm.

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