Mildew-proof antibacterial inorganic coating and preparation method thereof

Abstract

The invention belongs to the technical field of inorganic coatings, and particularly relates to a mildew-proof antibacterial inorganic coating and a preparation method thereof. The mildew-proof antibacterial inorganic coating is prepared from the following components in parts by weight: water, a thickening agent, a coalescing agent, a dispersing agent, a wetting agent, a defoaming agent, an antibacterial agent, KH-560 modified nano-silver, inorganic filler, styrene-acrylic emulsion, a stabilizer, silica sol and a KH-560 modified potassium silicate solution. Potassium silicate is used as a main inorganic film-forming substance to modify nano-silver and potassium silicate, the stability and water resistance of the coating are improved, the coating has long-term stable and efficient full-stage mildew-proof and antibacterial functions through the modified nano-silver and the antibacterial agent, and meanwhile the durability of concrete can be improved; by optimizing the stirring process and the feeding sequence, the storage stability and the film-forming property of the coating are further improved.

Description

Technical Field

[0001] The invention belongs to the technical field of inorganic coatings, and in particular relates to a mildew-proof and antibacterial inorganic coating and a preparation method thereof. Background Art

[0002] Water-based organic coatings are widely used in the field of architectural coatings. Although existing water-based organic coatings reduce VOC, organic coatings will inevitably breed mold after long-term service. This is because the organic matter contained in organic coatings is very easy to decompose in a humid environment. The carbon and nitrogen sources released in this process just constitute the basic nutrients required for mold growth, providing sufficient energy sources for mold and promoting the rapid reproduction of mold. With the development of science and technology and the improvement of living standards, people have new demands on architectural coatings. In addition to meeting the requirements of good durability and green environmental protection, they also need to beautify the image of the city and enhance the living experience.

[0003] At present, the anti-mildew and antibacterial inorganic coatings on the market mainly achieve the antibacterial effect by adding nano-oxides, but there are problems such as easy agglomeration of nanoparticles, slow antibacterial effect, and poor antibacterial effect. In view of this, there is a broad market demand for the development of an inorganic anti-mildew and antibacterial coating that can not only effectively have anti-mildew and antibacterial functions at all stages, but also has high durability and long-term stability.

[0004] Chinese patent CN109135366A discloses an inorganic coating with bactericidal and mildew-proof functions and its preparation method, which uses water, inorganic fillers, potassium silicate, emulsion, nanosilver, foam inhibitor, thickener, wetting agent, dispersant, chelating agent, defoamer, and stabilizer to prepare a bactericidal and mildew-proof inorganic coating. Although the coating has an antibacterial effect, it is not suitable for scenarios where antibacterial is required in the early stage because silver ions themselves have the problem of slow release.

[0005] Chinese patent CN118956186A discloses an anti-mildew and antibacterial inorganic coating and its preparation method, which includes: 17-26 parts of silica sol, 5-20 parts of resin, 10-13 parts of nano-modified material, 13-18 parts of filler, 15-41 parts of water, 4-25 parts of pigment, 0.5-4.5 parts of auxiliary agent, and 0.1-4 parts of diluent. The nano-modified materials used in the coating are nano zinc oxide, nano silver, and nano titanium dioxide, which are difficult to disperse and have lumps during preparation, and the film-forming effect is poor. Summary of the invention

[0006] In view of the defects existing in the prior art, the present invention provides an anti-mildew and antibacterial inorganic coating and a preparation method thereof. The coating has high bonding strength, excellent water resistance, good storage performance, and at the same time has high-efficiency full-stage anti-mildew and antibacterial functions, which can improve the durability of concrete.

[0007] In order to achieve the purpose of the present invention, the following technical solutions are specifically adopted:

[0008] A mildew and antibacterial inorganic coating, characterized in that it comprises the following components in parts by weight: 150-200 parts of water, 1-4 parts of thickener, 3-7 parts of film-forming aid, 7-12 parts of dispersant, 3-7 parts of wetting agent, 3-7 parts of defoamer, 0.5-2.5 parts of antibacterial agent, 10-50 parts of KH-560 modified nano silver, 350-500 parts of inorganic filler, 40-60 parts of styrene-acrylic emulsion, 4-8 parts of stabilizer, and 180-300 parts of silica sol and KH-560 modified potassium silicate solution.

[0009] In the present invention, the KH-560 refers to 3-glycidyloxypropyltrimethoxysilane. Studies have shown that if KH-560 in KH-560-modified nanosilver and silica sol and KH-560-modified potassium silicate solution is replaced with other silane coupling agents, the result is that the surface tension cannot be effectively reduced, the interfacial energy cannot be reduced, and the excellent stability is not achieved within the pH range.

[0010] Preferably, the preparation method of the KH-560 modified nanosilver comprises the following steps:

[0011] The nanosilver is mixed with KH-560, the pH is adjusted to 4-5, and then ultrasonic dispersion, mechanical stirring, and suction filtration are performed in sequence, and the solid is washed with toluene and then dried to obtain KH-560 modified nanosilver;

[0012] Wherein, based on the mass of nanosilver, the amount of KH-560 is 3-5%.

[0013] Further preferably, the temperature of the ultrasonic dispersion is 40-45°C and the time is 5-10 min;

[0014] The mechanical stirring time is 20 to 30 minutes.

[0015] Preferably, the method for preparing the silica sol and KH-560 modified potassium silicate solution comprises the following steps:

[0016] Add the potassium silicate solution into the reaction kettle, add silica sol dropwise while stirring, continue stirring until the solution is clear, then add KH-560 dropwise, continue stirring for a period of time to obtain silica sol and KH-560 modified potassium silicate solution;

[0017] Wherein, the modulus of the potassium silicate is 4 to 8, and the mass fraction of potassium silicate in the potassium silicate solution is 25 to 30%;

[0018] The solid content of the silica sol is 26-34wt%, and the amount of the silica sol is 15-25% based on the mass of the potassium silicate solution;

[0019] The amount of KH-560 used is 2-5% based on the total mass of the potassium silicate solution and the silica sol.

[0020] Further preferably, the method for preparing the silica sol and KH-560 modified potassium silicate solution comprises the following steps:

[0021] Add potassium silicate solution into the reaction kettle, add silica sol at a speed of 100-200 r / min, continue stirring at a speed of 300-500 r / min until the solution is clear, then add KH-560, continue stirring for 2-3 hours and cool to room temperature to obtain silica sol and KH-560 modified potassium silicate solution.

[0022] Preferably, the thickener comprises hydroxypropyl methylcellulose, xanthan gum and polyurethane thickener in a mass ratio of (1-2): (1-2): (6-10). Studies have found that the thickener using the above formula can significantly increase the viscosity and consistency of the liquid, improve rheology, help enhance stability, and maintain long-term use effects.

[0023] Preferably, the inorganic filler comprises rutile titanium dioxide, heavy calcium powder, talcum powder and silica powder in a mass ratio of (2-2.2): (1-1.2): (2-2.5): 2. Studies have found that the inorganic filler using the above formula can not only increase the hardness and strength of the coating, improve the wear resistance of the coating, but also improve the uniformity and stability of the coating, and can maintain good performance in extreme environments.

[0024] Preferably, the dispersant is at least one of a sodium polyacrylate dispersant and a sodium hexametaphosphate dispersant.

[0025] Preferably, the wetting agent is at least one of a nonionic surfactant or an anionic surfactant.

[0026] Preferably, the defoamer is at least one of a mineral oil defoamer or a silicone defoamer.

[0027] Preferably, the antibacterial agent is an isothiazolinone antibacterial agent.

[0028] Preferably, the film-forming aid is ester-12.

[0029] Preferably, the solid content of the styrene acrylic emulsion is 40-50wt%.

[0030] Preferably, the stabilizer is an organic-inorganic silicide.

[0031] The present invention also provides a method for preparing the above-mentioned mildew-proof and antibacterial inorganic coating, comprising the following steps:

[0032] (1) adding water and 40-50 wt% of a thickener into a reaction kettle, and stirring and dispersing at a speed of 300-400 r / min for 5-10 min;

[0033] (2) at a speed of 300 to 400 r / min, a dispersant, a wetting agent, an antibacterial agent, KH-560 modified nanosilver, and 30 to 40 wt % of a defoaming agent are added in sequence, and stirring and dispersing is continued for 10 to 15 minutes;

[0034] (3) At a speed of 300 to 400 r / min, add inorganic fillers in sequence, adjust the speed to 450 to 500 r / min, and stir and disperse for 30 to 40 minutes;

[0035] (4) At a speed of 450-500 r / min, add styrene-acrylic emulsion and stabilizer in sequence, and stir and disperse for 5-10 minutes;

[0036] (5) At a speed of 450 to 500 r / min, add silica sol and KH-560 modified potassium silicate solution, the remaining thickener, the remaining defoamer, and the film-forming aid in sequence, and stir and disperse for 5 to 10 minutes to obtain the product.

[0037] The beneficial effects of the present invention are at least:

[0038] 1) The mildew-proof and antibacterial inorganic coating provided by the present invention can improve the agglomeration phenomenon and dispersion stability of nanosilver by modifying the nanosilver with KH-560 solution, so that the nanosilver changes from hydrophilic to hydrophobic, and can improve the dispersion, stability and hydrophobicity of the nanosilver in the coating;

[0039] 2) The present invention provides an anti-mildew and antibacterial inorganic coating, which improves the film-forming property, storage stability and water resistance of the coating through the combined action of silica sol and potassium silicate; chemically modifies pure potassium silicate by KH-560 to form an organic-inorganic hybrid, thereby reducing the reactivity of potassium silicate and improving its stability; in addition, KH-560 can introduce a certain amount of alkyl substituents into the silicon atoms in the silica sol particles, replacing part of the K + , which can further improve the stability of the solution and the hardness and water resistance of the coating to a certain extent. The modified potassium silicate is more stable when mixed with fillers and is not easy to gel. It also has better compatibility when mixed with styrene acrylic emulsion and is not easy to produce flocculated particles;

[0040] 3) The mildew-proof and antibacterial inorganic coating provided by the present invention uses an antibacterial agent and KH-560 modified nano-silver to prevent mildew and inhibit bacteria in the entire process of storage, application and service of the coating;

[0041] 4) The present invention provides a method for preparing a mildew-proof and antibacterial inorganic coating, which further improves the storage stability and film-forming properties of the coating by optimizing the stirring process and the feeding sequence.

[0042] In summary, the mildew-proof and antibacterial inorganic coating provided by the present invention is coated on the surface of concrete. While ensuring aesthetics, it has high bonding strength, excellent water resistance, and good storage performance. At the same time, it has high-efficiency and full-stage mildew-proof and antibacterial functions, and has a certain improvement effect on the durability of concrete. It is easy for large-scale industrial production and simple to construct. It can be widely used in large-area exposed concrete projects such as roads, bridges, water conservancy projects, and ports. DETAILED DESCRIPTION

[0043] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with specific embodiments. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention. If no specific technology or conditions are specified in the examples, the technology or conditions described in the literature in this area or the product instructions are used.

[0044] In the following example:

[0045] The thickener is a mixture of hydroxypropyl methylcellulose, xanthan gum and polyurethane thickener, and the mass ratio of the three is 1:2:10; among them, hydroxypropyl methylcellulose comes from KS50000 hydroxypropyl methylcellulose of Shanghai Snow Chemical Technology Co., Ltd., polyurethane thickener comes from SN-7620 polyurethane thickener, and xanthan gum comes from HX xanthan gum of Hebei Haixi Chemical Co., Ltd.;

[0046] The film-forming aid was alcohol ester C12 from Wuxi Yijingfeng Technology Co., Ltd.;

[0047] The dispersant is HT-5020 sodium polyacrylate dispersant from Nantong Hantai Chemical Co., Ltd.

[0048] The wetting agent is an anionic surfactant from Zhejiang Fenghong New Materials Co., Ltd.;

[0049] The defoamer is a mineral oil defoamer from Shanghai Snow Chemical Technology Co., Ltd. SM-919;

[0050] The antibacterial agent is an isothiazolinone antibacterial agent, which is derived from the DF fungicide of Nantong Hantai Chemical Co., Ltd.

[0051] The solid content of the styrene acrylic emulsion is 49%, which is derived from BC-991 styrene acrylic emulsion of Huateng Jichun Technology Co., Ltd.

[0052] The stabilizer was derived from an organic-inorganic silicide stabilizer (S3) from Shanghai Aorun Co., Ltd.

[0053] Example 1

[0054] A mildew-proof and antibacterial inorganic coating comprises the following components by weight: 150 parts of water, 1 part of thickener, 7 parts of film-forming aid, 12 parts of dispersant, 7 parts of wetting agent, 3 parts of defoamer, 0.5 parts of antibacterial agent, 10 parts of modified nano silver, 350 parts of inorganic filler, 60 parts of styrene-acrylic emulsion, 4 parts of stabilizer and 180 parts of modified potassium silicate.

[0055] The modified nanosilver is prepared by the following method:

[0056] KH-560 silane coupling agent was mixed with nanosilver, the pH was adjusted to 4, ultrasonic dispersion was performed in a constant temperature water bath at 45°C for 5 minutes, mechanical stirring was performed for 20 minutes, suction filtration was performed, the mixture was washed with toluene, and vacuum drying was performed at 60°C for 24 hours to obtain modified nanosilver;

[0057] Wherein, based on the mass of nanosilver, the amount of KH-560 is 3%.

[0058] Modified potassium silicate is prepared by the following method:

[0059] At room temperature, a certain amount of potassium silicate solution was added to the reaction kettle, and a silica sol (solid content of silica sol is 30%, the same below) with a mass fraction of 15% of the potassium silicate solution was added dropwise at a speed of 100 r / min, and the mixture was stirred continuously at 500 r / min until the solution was clear, and 2% of the total mass of KH-560 was slowly added dropwise, and the mixture was stirred continuously for 2 hours and then cooled to room temperature to obtain modified potassium silicate;

[0060] The modulus of the potassium silicate is 6, and the mass fraction of potassium silicate in the potassium silicate solution is 28%.

[0061] The preparation method of the mildew-proof and antibacterial inorganic coating described in this embodiment comprises the following steps:

[0062] (1) First, water and 40% thickener were added into the reactor and stirred at a speed of 300 r / min for 5 min.

[0063] (2) Add dispersant, wetting agent, antibacterial agent, modified nano silver, and 30 wt% defoaming agent in sequence, and continue dispersing for 15 minutes.

[0064] (3) Then, titanium dioxide, heavy calcium powder, talcum powder, and silica powder are added in sequence at a speed of 400 r / min. The mass ratio of the four is 2:1:2:2. The speed is adjusted to 500 r / min and stirred for 40 minutes.

[0065] (4) At a speed of 500 r / min, add styrene acrylic emulsion and stabilizer in sequence and disperse for 5 minutes.

[0066] (5) Finally, add modified potassium silicate, remaining thickener, remaining defoamer, and film-forming aid in sequence and disperse for 5 minutes.

[0067] Example 2

[0068] A mildew-proof and antibacterial inorganic coating comprises the following components by weight: 200 parts of water, 4 parts of thickener, 3 parts of film-forming aid, 7 parts of dispersant, 3 parts of wetting agent, 7 parts of defoamer, 2.5 parts of antibacterial agent, 50 parts of modified nano silver, 500 parts of inorganic filler, 40 parts of styrene-acrylic emulsion, 8 parts of stabilizer and 300 parts of modified potassium silicate.

[0069] The modified nanosilver is prepared by the following method:

[0070] KH-560 silane coupling agent was mixed with nanosilver, the pH was adjusted to 5, ultrasonic dispersion was performed in a constant temperature water bath at 40°C for 5 minutes, mechanical stirring was performed for 30 minutes, suction filtration was performed, the mixture was washed with toluene, and vacuum drying was performed at 70°C for 24 hours to obtain modified nanosilver;

[0071] Wherein, based on the mass of nanosilver, the amount of KH-560 is 5%.

[0072] Modified potassium silicate is prepared by the following method:

[0073] At room temperature, a certain amount of potassium silicate solution was added to the reactor, and a silica sol with a mass fraction of 25% of the potassium silicate solution was added dropwise at a speed of 200 r / min, and the mixture was continuously stirred at 300 r / min until the solution was clear, and 5% of the total mass of KH-560 was slowly added dropwise, and the mixture was continuously stirred for 3 hours and then cooled to room temperature to obtain modified potassium silicate;

[0074] The modulus of the potassium silicate is 6, and the mass fraction of potassium silicate in the potassium silicate solution is 28%.

[0075] The preparation method of the mildew-proof and antibacterial inorganic coating described in this embodiment comprises the following steps:

[0076] (1) First, add water and 50% thickener into the reactor and stir at a speed of 400 r / min for 5 min.

[0077] (2) Add dispersant, wetting agent, antibacterial agent, modified nanosilver, and 40% defoaming agent in sequence and continue dispersing for 10 minutes.

[0078] (3) Then, titanium dioxide, heavy calcium powder, talcum powder, and silica powder are added in sequence at a speed of 300 r / min. The mass ratio of the four is 2.2:1.2:2.5:2. The speed is adjusted to 450 r / min and stirred for 30 min.

[0079] (4) At a speed of 450 r / min, add styrene acrylic emulsion and stabilizer in sequence and disperse for 5 minutes.

[0080] (5) Finally, add modified potassium silicate, remaining thickener, remaining defoamer, and film-forming aid in sequence and disperse for 5 minutes.

[0081] Example 3

[0082] A mildew-proof and antibacterial inorganic coating comprises the following components by weight: 180 parts of water, 2 parts of a thickener, 5 parts of a film-forming aid, 10 parts of a dispersant, 5 parts of a wetting agent, 5 parts of a defoaming agent, 1.5 parts of an antibacterial agent, 25 parts of modified nano silver, 450 parts of an inorganic filler, 50 parts of a styrene-acrylic emulsion, 4 parts of a stabilizer, and 250 parts of modified potassium silicate.

[0083] The modified nanosilver is prepared by the following method:

[0084] KH-560 silane coupling agent was mixed with nanosilver, the pH was adjusted to 4, ultrasonic dispersion was performed in a constant temperature water bath at 40°C for 5 minutes, mechanical stirring was performed for 25 minutes, suction filtration was performed, the mixture was washed with toluene, and vacuum drying was performed at 65°C for 24 hours to obtain modified nanosilver;

[0085] Wherein, based on the mass of nanosilver, the amount of KH-560 is 4%.

[0086] Modified potassium silicate is prepared by the following method:

[0087] At room temperature, a certain amount of potassium silicate solution was added to the reactor, and a silica sol with a mass fraction of 20% of the potassium silicate solution was added dropwise at a speed of 150 r / min, and the mixture was continuously stirred at 400 r / min until the solution was clear, and 4% of the total mass of KH-560 was slowly added dropwise, and the mixture was continuously stirred for 2.5 h and then cooled to room temperature to obtain modified potassium silicate;

[0088] The modulus of the potassium silicate is 6, and the mass fraction of potassium silicate in the potassium silicate solution is 28%.

[0089] The preparation method of the mildew-proof and antibacterial inorganic coating described in this embodiment comprises the following steps:

[0090] (1) First, water and 45% thickener were added into the reactor and stirred at a speed of 350 r / min for 5 min.

[0091] (2) Add dispersant, wetting agent, antibacterial agent, modified nanosilver, and 35% defoaming agent in sequence and continue dispersing for 12 minutes.

[0092] (3) Then, titanium dioxide, heavy calcium powder, talcum powder, and silica powder are added in sequence at a speed of 350 r / min. The mass ratio of the four is 2.1:1.1:2.3:2. The speed is adjusted to 470 r / min and stirred for 35 min.

[0093] (4) At a speed of 470 r / min, add styrene acrylic emulsion and stabilizer in sequence and disperse for 5 minutes.

[0094] (5) Finally, add modified potassium silicate, remaining thickener, remaining defoamer, and film-forming aid in sequence and disperse for 5 minutes.

[0095] Comparative Example 1

[0096] A mildew-proof and antibacterial inorganic coating comprises the following components by weight: 150 parts of water, 1 part of thickener, 7 parts of film-forming aid, 12 parts of dispersant, 7 parts of wetting agent, 3 parts of defoamer, 0.5 parts of antibacterial agent, 10 parts of nano silver, 350 parts of inorganic filler, 60 parts of styrene-acrylic emulsion, 4 parts of stabilizer and 180 parts of modified potassium silicate.

[0097] Modified potassium silicate is prepared by the following method:

[0098] At room temperature, a certain amount of potassium silicate solution was added to the reactor, and a silica sol with a mass fraction of 15% of the potassium silicate solution was added dropwise at a speed of 100 r / min, and the mixture was continuously stirred at 500 r / min until the solution was clear, and 2% of the total mass of KH-560 was slowly added dropwise, and the mixture was continuously stirred for 2 hours and then cooled to room temperature to obtain modified potassium silicate;

[0099] The modulus of the potassium silicate is 6, and the mass fraction of potassium silicate in the potassium silicate solution is 28%.

[0100] The preparation method of the mildew-proof and antibacterial inorganic coating described in this comparative example comprises the following steps:

[0101] (1) First, water and 40% thickener were added into the reactor and stirred at a speed of 300 r / min for 5 min.

[0102] (2) Add dispersant, wetting agent, antibacterial agent, nanosilver, and 30% defoaming agent in sequence and continue dispersing for 15 minutes.

[0103] (3) Then, titanium dioxide, heavy calcium powder, talcum powder, and silica powder are added in sequence at a speed of 400 r / min. The mass ratio of the four is 2:1:2:2. The speed is adjusted to 500 r / min and stirred for 40 minutes.

[0104] (4) At a speed of 500 r / min, add styrene acrylic emulsion and stabilizer in sequence and disperse for 5 minutes.

[0105] (5) Finally, add modified potassium silicate, remaining thickener, remaining defoamer, and film-forming aid in sequence and disperse for 5 minutes.

[0106] Comparative Example 2

[0107] A mildew-proof and antibacterial inorganic coating, comprising the following components by weight: 200 parts of water, 4 parts of thickener, 3 parts of film-forming aid, 7 parts of dispersant, 3 parts of wetting agent, 7 parts of defoamer, 2.5 parts of antibacterial agent, 50 parts of modified nano silver, 500 parts of inorganic filler, 40 parts of styrene-acrylic emulsion, 8 parts of stabilizer, and 300 parts of potassium silicate solution;

[0108] The modulus of the potassium silicate is 6, and the mass fraction of potassium silicate in the potassium silicate solution is 28%.

[0109] The modified nanosilver is prepared by the following method:

[0110] KH-560 silane coupling agent was mixed with nanosilver, the pH was adjusted to 5, ultrasonic dispersion was performed in a constant temperature water bath at 40°C for 5 minutes, mechanical stirring was performed for 30 minutes, suction filtration was performed, the mixture was washed with toluene, and vacuum drying was performed at 70°C for 24 hours to obtain modified nanosilver;

[0111] Wherein, based on the mass of nanosilver, the amount of KH-560 is 5%.

[0112] The preparation method of the mildew-proof and antibacterial inorganic coating described in this comparative example comprises the following steps:

[0113] (1) First, add water and 50% thickener into the reactor and stir at a speed of 400 r / min for 5 minutes.

[0114] (2) Add dispersant, wetting agent, antibacterial agent, modified nanosilver, and 40% defoaming agent in sequence and continue dispersing for 10 minutes.

[0115] (3) Then, titanium dioxide, heavy calcium powder, talcum powder, and silica powder are added in sequence at a speed of 300 r / min. The mass ratio of the four is 2.2:1.2:2.5:2. The speed is adjusted to 450 r / min and stirred for 30 min.

[0116] (4) At a speed of 450 r / min, add styrene acrylic emulsion and stabilizer in sequence and disperse for 5 minutes.

[0117] (5) Finally, add potassium silicate solution, remaining thickener, remaining defoamer, and film-forming aid in sequence and disperse for 5 minutes.

[0118] Comparative Example 3

[0119] A mildew and antibacterial inorganic coating comprises the following components by weight: 180 parts of water, 2 parts of thickener, 5 parts of film-forming aid, 10 parts of dispersant, 5 parts of wetting agent, 5 parts of defoamer, 450 parts of inorganic filler, 50 parts of styrene acrylic emulsion, 4 parts of stabilizer and 250 parts of modified potassium silicate.

[0120] Modified potassium silicate is prepared by the following method:

[0121] At room temperature, a certain amount of potassium silicate solution was added to the reactor, and a silica sol with a mass fraction of 20% of the potassium silicate solution was added dropwise at a speed of 150 r / min, and the mixture was continuously stirred at 400 r / min until the solution was clear, and 4% of the total mass of KH-560 was slowly added dropwise, and the mixture was continuously stirred for 2.5 h and then cooled to room temperature to obtain modified potassium silicate;

[0122] The modulus of the potassium silicate is 6, and the mass fraction of potassium silicate in the potassium silicate solution is 28%.

[0123] The preparation method of the mildew-proof and antibacterial inorganic coating described in this comparative example comprises the following steps:

[0124] (1) First, water and 45% thickener were added into the reactor and stirred at a speed of 350 r / min for 5 min.

[0125] (2) Add dispersant, wetting agent and 35% defoaming agent in sequence and continue dispersing for 12 minutes.

[0126] (3) Then, titanium dioxide, heavy calcium powder, talcum powder, and silica powder are added in sequence at a speed of 350 r / min. The mass ratio of the four is 2.1:1.1:2.3:2. The speed is adjusted to 470 r / min and stirred for 35 min.

[0127] (4) At a speed of 470 r / min, add styrene acrylic emulsion and stabilizer in sequence and disperse for 5 minutes.

[0128] (5) Finally, add modified potassium silicate, remaining thickener, remaining defoamer, and film-forming aid in sequence and disperse for 5 minutes.

[0129] Comparative Example 4

[0130] A mildew-proof and antibacterial inorganic coating comprises the following components by weight: 150 parts of water, 1 part of thickener, 7 parts of film-forming aid, 12 parts of dispersant, 7 parts of wetting agent, 3 parts of defoamer, 0.5 parts of antibacterial agent, 10 parts of modified nano silver, 350 parts of inorganic filler, 60 parts of styrene-acrylic emulsion, 4 parts of stabilizer and 180 parts of modified potassium silicate.

[0131] The modified nanosilver is prepared by the following method:

[0132] KH-560 silane coupling agent was mixed with nanosilver, the pH was adjusted to 4, ultrasonic dispersion was performed in a constant temperature water bath at 45°C for 5 minutes, mechanical stirring was performed for 20 minutes, suction filtration was performed, the mixture was washed with toluene, and vacuum drying was performed at 60°C for 24 hours to obtain modified nanosilver;

[0133] Wherein, based on the mass of nanosilver, the amount of KH-560 is 3%.

[0134] Modified potassium silicate is prepared by the following method:

[0135] At room temperature, a certain amount of potassium silicate solution was added to the reactor, and a silica sol with a mass fraction of 15% of the potassium silicate solution was added dropwise at a speed of 100 r / min, and the mixture was continuously stirred at 500 r / min until the solution was clear, and 2% of the total mass of KH-560 was slowly added dropwise, and the mixture was continuously stirred for 2 hours and then cooled to room temperature to obtain modified potassium silicate;

[0136] The modulus of the potassium silicate is 6, and the mass fraction of potassium silicate in the potassium silicate solution is 28%.

[0137] The preparation method of the mildew-proof and antibacterial inorganic coating described in this comparative example comprises the following steps:

[0138] (1) First, add water and thickener into the reactor and stir at a speed of 200 r / min for 5 min.

[0139] (2) Add dispersant, wetting agent, antibacterial agent, modified nanosilver, defoaming agent and film-forming aid in sequence and continue dispersing for 5 minutes.

[0140] (3) Then, titanium dioxide, heavy calcium powder, talcum powder, and silica powder are added in sequence at a speed of 200 r / min. The mass ratio of the four is 2:1:2:2. The speed is adjusted to 400 r / min and stirred for 20 min.

[0141] (4) At a speed of 500 r / min, add styrene acrylic emulsion and stabilizer in sequence and disperse for 5 minutes.

[0142] (5) Finally, add modified potassium silicate and disperse for 5 minutes.

[0143] Test example

[0144] According to the proportions in Table 1, the base concrete is formed, and the anti-mildew and antibacterial inorganic coating is applied on the surface. The specific steps are as follows:

[0145] (1) Carry out base treatment on the concrete surface: Grind the concrete surface to ensure that it is flat, dense and solid, and remove surface slurry, dust, oil, mold, etc.;

[0146] (2) Apply a layer of anti-mildew and antibacterial inorganic coating to the treated concrete surface, and then apply a second layer of anti-mildew and antibacterial inorganic coating after drying for 2 hours.

[0147] Table 1 Base concrete mix ratio

[0148]

[0149] The concrete water absorption ratio was tested with reference to JC474-2008 "Mortar Concrete Waterproofing Agent", the electric flux and anti-seepage pressure were tested according to GBT 50082-2009 "Standard for Test Methods for Long-term Performance and Durability of Ordinary Concrete", the bonding strength was tested according to JCT 864-2008 "Polymer Emulsion Building Waterproof Coating", and the water resistance, alkali resistance, washability, low-temperature storage and hot storage stability were tested according to JG / T 335-2011 "Exterior Wall Inorganic Building Coatings". A 15cm×15cm×15cm test block was placed outdoors for 180 days for long-term mildew performance observation. The results are shown in Table 2.

[0150] Table 2 Performance indexes of embodiments and comparative examples

[0151]

[0152]

[0153] It can be clearly seen from Table 2 that in Examples 1-3, due to the different addition amounts of KH-560 silane coupling agent in the modified nanosilver and KH-560 in the modified potassium silicate, the water absorption is different, and the addition amount of film-forming aid and styrene acrylic emulsion will affect the film-forming effect, which is manifested in different bonding strength, scrub resistance and anti-seepage pressure; Comparative Example 1 did not modify the nanosilver, which affected the dispersibility, stability, water resistance and late mildew resistance of the coating, which was manifested in the storage stability, long-term mildew resistance, bonding strength, anti-seepage pressure of Comparative Example 1. The pressure and washability are lower than those in the embodiment; the potassium silicate is not modified in the comparative example 2, which is manifested as the water resistance, washability, storage stability, bonding strength and anti-seepage pressure of the comparative example 2 are lower than those in the embodiment; the antibacterial agent and modified nano-silver are not added in the comparative example 3, which is manifested as the mildew of the early products of the comparative example 3, and the long-term mildew-proof effect is poor; since the stirring process and the feeding sequence of the comparative example 4 are not optimized, the comparative example 4 has the problem of storage stability, and the water resistance, bonding strength, anti-seepage pressure and washability are reduced.

[0154] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A mildew-proof and antibacterial inorganic coating, characterized in that: The invention comprises the following components by weight: 150-200 parts of water, 1-4 parts of thickener, 3-7 parts of film-forming aid, 7-12 parts of dispersant, 3-7 parts of wetting agent, 3-7 parts of defoaming agent, 0.5-2.5 parts of antibacterial agent, 10-50 parts of KH-560 modified nano silver, 350-500 parts of inorganic filler, 40-60 parts of styrene-acrylic emulsion, 4-8 parts of stabilizer, and 180-300 parts of silica sol and KH-560 modified potassium silicate solution.

2. The mildew-proof and antibacterial inorganic coating according to claim 1, characterized in that: The preparation method of the KH-560 modified nanosilver comprises the following steps: The nanosilver is mixed with KH-560, the pH is adjusted to 4-5, and then ultrasonic dispersion, mechanical stirring, and suction filtration are performed in sequence, and the solid is washed with toluene and then dried to obtain KH-560 modified nanosilver; Wherein, based on the mass of nanosilver, the amount of KH-560 is 3-5%.

3. The mildew-proof and antibacterial inorganic coating according to claim 2, characterized in that: The ultrasonic dispersion temperature is 40-45°C and the time is 5-10 minutes; The mechanical stirring time is 20 to 30 minutes.

4. The mildew and antibacterial inorganic coating according to any one of claims 1 to 3, characterized in that: The preparation method of the silica sol and KH-560 modified potassium silicate solution comprises the following steps: Add the potassium silicate solution into the reaction kettle, add silica sol dropwise while stirring, continue stirring until the solution is clear, then add KH-560 dropwise, continue stirring for a period of time to obtain silica sol and KH-560 modified potassium silicate solution; Wherein, the modulus of the potassium silicate is 4 to 8, and the mass fraction of potassium silicate in the potassium silicate solution is 25 to 30%; The solid content of the silica sol is 26-34wt%, and the amount of the silica sol is 15-25% based on the mass of the potassium silicate solution; The amount of KH-560 used is 2-5% based on the total mass of the potassium silicate solution and the silica sol.

5. The mildew-proof and antibacterial inorganic coating according to claim 4, characterized in that: The preparation method of the silica sol and KH-560 modified potassium silicate solution comprises the following steps: Add potassium silicate solution into the reaction kettle, add silica sol at a speed of 100-200 r / min, continue stirring at a speed of 300-500 r / min until the solution is clear, then add KH-560, continue stirring for 2-3 hours and cool to room temperature to obtain silica sol and KH-560 modified potassium silicate solution.

6. The mildew and antibacterial inorganic coating according to any one of claims 1 to 3, characterized in that: The thickener comprises hydroxypropyl methylcellulose, xanthan gum and polyurethane thickener in a mass ratio of (1-2):(1-2):(6-10).

7. The mildew and antibacterial inorganic coating according to any one of claims 1 to 3, characterized in that: The inorganic filler comprises rutile titanium dioxide, heavy calcium powder, talcum powder and silica powder in a mass ratio of (2-2.2):(1-1.2):(2-2.5):

2.

8. The mildew and antibacterial inorganic coating according to any one of claims 1 to 3, characterized in that: The dispersant is at least one of a sodium polyacrylate dispersant and a sodium hexametaphosphate dispersant; and / or, the wetting agent is at least one of a nonionic surfactant or an anionic surfactant; and / or, the defoamer is at least one of a mineral oil defoamer or a silicone defoamer; and / or, the antibacterial agent is an isothiazolinone antibacterial agent; And / or, the film-forming aid is alcohol ester-12; And / or, the solid content of the styrene-acrylic emulsion is 40-50wt%; And / or, the stabilizer is an organic-inorganic silicide.

9. The method for preparing the mildew-proof and antibacterial inorganic coating according to any one of claims 1 to 8, characterized in that: The following steps are involved: (1) adding water and 40-50 wt% of a thickener into a reaction kettle, and stirring and dispersing at a speed of 300-400 r / min for 5-10 min; (2) at a speed of 300 to 400 r / min, a dispersant, a wetting agent, an antibacterial agent, KH-560 modified nanosilver, and 30 to 40 wt % of a defoaming agent are added in sequence, and stirring and dispersing is continued for 10 to 15 minutes; (3) At a speed of 300 to 400 r / min, add inorganic fillers in sequence, adjust the speed to 450 to 500 r / min, and stir and disperse for 30 to 40 minutes; (4) At a speed of 450-500 r / min, add styrene-acrylic emulsion and stabilizer in sequence, and stir and disperse for 5-10 minutes; (5) At a speed of 450 to 500 r / min, add silica sol and KH-560 modified potassium silicate solution, the remaining thickener, the remaining defoamer, and the film-forming aid in sequence, and stir and disperse for 5 to 10 minutes to obtain the product.

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