Single-component self-permeable coating for foamed ceramic and preparation method of single-component self-permeable coating

Abstract

The invention belongs to the technical field of building materials, and particularly relates to a single-component self-permeable coating for foamed ceramics and a preparation method of the single-component self-permeable coating. The components of the coating are subjected to modification treatment, firstly, polyvinyl alcohol is subjected to grafting modification treatment and then mixed with sodium carboxymethyl cellulose to prepare the polyvinyl alcohol glue, and then the polyvinyl alcohol glue is matched with two different modified quartz sands to be used together, so that the compressive strength and the bonding strength of the coating are effectively improved, and meanwhile, the water absorption rate and the shrinkage rate are reduced.

Description

Technical Field

[0001] The present application belongs to the technical field of building materials, and specifically relates to a single-component self-penetrating coating for foamed ceramics and a preparation method thereof. Background Art

[0002] Foamed ceramics have the characteristics of dense pores, unconnected pores, and low absorption. With the extensive application of foamed ceramics, professional interface reinforcement materials are required to solve the following pain points during splicing, installation, and painting, so as to give full play to the huge advantages of foamed ceramics. Directly brushing or spraying paint, scraping putty and other materials on the porous surface of foamed ceramics cannot fill the holes, and a large number of bubbles will be generated, and multiple constructions are required to cover the closed pores; for exterior wall decoration, ordinary putty and paint are directly applied to the surface of foamed ceramics, and the weather resistance, water resistance, and freeze-thaw resistance are poor. The bonding strength is greatly reduced after the freeze-thaw cycle, and it is very easy to produce hollowing and falling risks; cement mortar or ordinary tile adhesive is used for foamed ceramic splicing seam treatment and wall installation, which cannot prevent rainwater from penetrating from the back of the joint from the inside to the outside, and cannot be firmly bonded for a long time, and it is easy to hollow and fall off.

[0003] A Chinese patent (publication number CN116426173B) discloses a self-leveling penetrating crystallization waterproof coating and its application. The waterproof coating can achieve full penetration of active crystalline substances by itself without maintenance process through self-locking water, which can not only improve the waterproof performance of the concrete base but also form its own waterproof layer, and can close the ventilation channel between the concrete and the outside to prevent the generation of bubbles in the construction of the next waterproof or decorative coating. It also has excellent self-leveling performance and can easily achieve the leveling function for the concrete foundation. For example, waterproof coiled materials can be directly laid on it without additional grinding and leveling operations. However, when the self-penetrating coating is applied to foamed ceramics in the prior art, there will be problems such as low compressive strength and bonding strength, high water absorption, and large shrinkage, which seriously affect its actual use.

[0004] Therefore, there is an urgent need for a single-component self-penetrating coating for foamed ceramics, which can effectively improve the compressive strength and bonding strength of the coating by modifying the coating components, while reducing water absorption and shrinkage. Summary of the invention

[0005] In view of the above problems, the purpose of the present invention is to provide a single-component self-penetrating coating for foamed ceramics and a preparation method thereof. By modifying the coating components, polyvinyl alcohol is first grafted and modified, and then mixed with sodium carboxymethyl cellulose to prepare polyvinyl alcohol glue, which is then used together with two different modified quartz sands to effectively improve the compressive strength and bonding strength of the coating, while reducing water absorption and shrinkage.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] The first aspect of the present application provides a one-component self-penetrating coating for foamed ceramics, which comprises the following components, in parts by weight: 3 to 5 parts of deionized water, 8 to 10 parts of polyvinyl alcohol glue, 16 to 20 parts of pure acrylic emulsion, 40 to 50 parts of quartz sand, 1 to 2 parts of water reducer, 1 to 2 parts of bactericide, 2 to 4 parts of dispersant, 3 to 5 parts of wetting agent and 1.2 to 1.8 parts of defoamer;

[0008] The preparation method of the polyvinyl alcohol glue comprises: mixing 80 to 100 parts of deionized water and 16 to 20 parts of acetone by weight, and then adding 3 to 5 parts of sodium carboxymethyl cellulose and stirring to dissolve to obtain a sodium carboxymethyl cellulose solution; adding 8 to 10 parts of commercially available polyvinyl alcohol to 90 to 100 parts of deionized water to fully dissolve, and then adding 2 to 6 parts of γ-glycidyloxypropyltrimethoxysilane for grafting modification treatment, and then adding 40 to 50 parts of the sodium carboxymethyl cellulose solution and stirring to obtain the polyvinyl alcohol glue.

[0009] In some embodiments of the present application, the conditions for the grafting modification treatment include: controlling the temperature to 50-60° C., adjusting the pH to 7.2-7.4, and stirring at a speed of 200-240 r / min for 100-120 min.

[0010] In some embodiments of the present application, the molecular weight of the commercially available polyvinyl alcohol is 5,000 to 10,000.

[0011] The siloxane groups introduced after the grafting modification of polyvinyl alcohol in polyvinyl alcohol glue can form covalent bonds with the surface of the substrate, thereby significantly enhancing the interfacial bonding force between the coating and the substrate and improving the bonding strength; at the same time, the silicon-oxygen bonds formed after the hydrolysis of the siloxane groups can establish chemical bridges between polyvinyl alcohol and sodium carboxymethyl cellulose, enhancing the density and rigidity of the material and improving the compressive strength.

[0012] In some embodiments of the present application, the 40 to 50 parts of quartz sand include 20 to 25 parts of quartz sand I and 20 to 25 parts of quartz sand II.

[0013] In some embodiments of the present application, the preparation method of the quartz sand I includes: mixing 90 to 100 parts of deionized water and 90 to 100 parts of anhydrous ethanol, by weight, and then adding 20 to 25 parts of 600 mesh quartz sand for ultrasonic dispersion, and then adding 3 to 5 parts of hexadecyltrimethylammonium bromide for hydrophobic modification to obtain quartz sand I.

[0014] In some embodiments of the present application, the conditions for the hydrophobic modification treatment include: controlling the temperature to 60-70° C., stirring at a speed of 80-100 r / min for 4-6 hours, and vacuum drying.

[0015] Quartz sand I is treated with hydrophobic modification to graft the hydrophobic groups of hexadecyltrimethylammonium bromide onto the surface of 600 mesh quartz sand. By introducing hydrophobic long chains, a hydrophobic film is formed on the surface of the quartz sand to prevent water penetration. At the same time, hexadecyltrimethylammonium bromide can fill the micropores on the surface of the quartz sand, reduce the porosity of the coating, reduce water adsorption, and the combined effect reduces the water absorption rate.

[0016] In some embodiments of the present application, the preparation method of quartz sand II includes: pre-treating 20 to 25 parts of 100 mesh quartz sand by weight, and then dispersing it in a mixture of 10 to 20 parts of deionized water and 180 to 190 parts of anhydrous ethanol, adding 6 to 10 parts of nano-silicon dioxide and stirring evenly, and then adding 6 to 12 parts of 3-aminopropyltriethoxysilane for surface functionalization treatment to obtain quartz sand II.

[0017] In some embodiments of the present application, the pretreatment conditions include: washing 20 to 25 parts of 100 mesh quartz sand with deionized water for 3 to 5 times, drying, and then adding it to 40 to 50 parts of a hydrochloric acid solution with a mass concentration of 26 to 30% and soaking it for 30 to 40 minutes, washing it with water until the pH is neutral, and drying it to obtain acid-treated quartz sand; adding 20 to 25 parts of the acid-treated quartz sand to a sodium hydroxide solution with a mass concentration of 8 to 10% and soaking it for 40 to 50 minutes, washing it with water until the pH is neutral, and drying it to obtain pretreated quartz sand.

[0018] In some embodiments of the present application, the conditions for the surface functionalization treatment include: adjusting the pH to 4.4-4.8, treating at 50-60° C. for 2-4 hours, and vacuum drying.

[0019] The 100-mesh quartz sand in quartz sand II is more rigid and can provide physical support to limit the volume shrinkage of the coating during the curing process. The introduced nano-silica can fill the micropores between the 100-mesh quartz sand and the coating matrix to reduce interface defects. At the same time, quartz sand II modified with 3-aminopropyltriethoxysilane limits the rearrangement of polymer chains in the coating through cross-linking and filling, thereby reducing the shrinkage rate of the material.

[0020] In some embodiments of the present application, the defoaming agent is polydimethylsiloxane and tributyl phosphate; the mass ratio of polydimethylsiloxane to tributyl phosphate in the defoaming agent is (1-2):1.

[0021] The second aspect of the present application provides a method for preparing the single-component self-penetrating coating for foamed ceramics as described in the first aspect.

[0022] The steps include:

[0023] In parts by weight, 3-5 parts of deionized water, 8-10 parts of polyvinyl alcohol glue and 16-20 parts of pure acrylic emulsion are mixed and stirred for 40-60 minutes, and then 40-50 parts of quartz sand, 1-2 parts of water reducer, 1-2 parts of fungicide, 2-4 parts of dispersant, 3-5 parts of wetting agent and 1.2-1.8 parts of defoamer are added and stirred to obtain a single-component self-penetrating coating for foamed ceramics.

[0024] Compared with the prior art, the present application at least achieves the following technical effects:

[0025] (1) The present invention first performs a grafting modification treatment on polyvinyl alcohol, and then mixes it with sodium carboxymethyl cellulose to prepare polyvinyl alcohol glue. The sodium carboxymethyl cellulose in the polyvinyl alcohol glue presents a negative charge, while the quaternary ammonium cation of hexadecyltrimethylammonium bromide in quartz sand I carries a positive charge. The two can form a first network structure through electrostatic attraction; at the same time, the amino group introduced into quartz sand II through the modification treatment will also combine with the unreacted silanol and epoxy groups in the polyvinyl alcohol glue to form a second network structure. The bonding strength is improved through the action of the siloxane group in the double network structure and the matrix. At the same time, the dense structure can also effectively improve the compressive strength of the coating. In addition, the high-density cross-linked network can effectively block moisture penetration and thus reduce water absorption. The silicon dioxide nanomaterial distributed in the network structure can reduce the shrinkage rate of the coating through high specific surface area and strong interface action.

[0026] (2) The siloxane groups introduced into the polyvinyl alcohol glue after the polyvinyl alcohol grafting modification treatment can form covalent bonds with the surface of the substrate, thereby significantly enhancing the interfacial bonding force between the coating and the substrate and improving the bonding strength; at the same time, the silicon-oxygen bonds formed after the hydrolysis of the siloxane groups can establish chemical bridges between the polyvinyl alcohol and sodium carboxymethyl cellulose, thereby enhancing the density and rigidity of the material and improving the compressive strength.

[0027] (3) The quartz sand I of the present invention is subjected to hydrophobic modification treatment to graft the hydrophobic groups of hexadecyltrimethylammonium bromide onto the surface of 600 mesh quartz sand. By introducing hydrophobic long chains, a hydrophobic film is formed on the surface of the quartz sand to prevent water penetration. At the same time, hexadecyltrimethylammonium bromide can fill the micropores on the surface of the quartz sand, reduce the porosity of the coating, and reduce water adsorption. The comprehensive effect reduces the water absorption rate.

[0028] The 100-mesh quartz sand in the quartz sand II of the present invention has strong rigidity, can provide physical support, and limit the volume shrinkage of the coating during the curing process, while the introduced nano-silicon dioxide can fill the micropores between the 100-mesh quartz sand and the coating matrix to reduce interface defects, and at the same time, the quartz sand II modified with 3-aminopropyltriethoxysilane limits the rearrangement of the polymer chain in the coating through cross-linking and filling, thereby reducing the shrinkage rate of the material. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the present invention more clear, the present invention is further described in detail below. However, it should be understood that the description herein is only used to explain the present invention and is not used to limit the scope of the present invention.

[0030] Unless otherwise defined, all technical terms and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present invention, and the terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The reagents and instruments used herein are all commercially available, and the characterization means involved can refer to the relevant descriptions in the prior art, which will not be repeated herein.

[0031] The sources of some components in the embodiments and comparative examples are as follows:

[0032] Polyvinyl alcohol I, product number P434372, molecular weight 9000-10000, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0033] Polyvinyl alcohol II, product number P434371, molecular weight 89000-98000, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0034] Pure acrylic emulsion, product number 2891, purchased from Wuhan Jiyesheng Chemical Co., Ltd.;

[0035] 600 mesh quartz sand, purchased from Guangdong Yuanlei Powder Co., Ltd.;

[0036] 100 mesh quartz sand, purchased from Chongqing Qianyi Building Materials Co., Ltd.;

[0037] Polycarboxylate water reducer, product number SP-409, purchased from Liaoning Kelong Fine Chemical Co., Ltd.;

[0038] Bactericide, isothiazolinone, CAS No. 55965-84-9, purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0039] Dispersant, item number 2410, purchased from Dongguan Yilian Chemical Technology Co., Ltd.

[0040] Wetting agent, model X-405, purchased from Dow Chemical;

[0041] Polydimethylsiloxane, CAS No. 9006-65-9, was purchased from Shanghai MacLean Biochemical Technology Co., Ltd.;

[0042] Tributyl phosphate, CAS No. 126-73-8, was purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0043] Sodium carboxymethyl cellulose, CAS No. 9004-32-4, was purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0044] γ-Glycidyloxypropyltrimethoxysilane, CAS No. 2530-83-8, purchased from Shanghai MacLean Biochemical Technology Co., Ltd.;

[0045] Hexadecyltrimethylammonium bromide, CAS No. 57-09-0, was purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0046] Nanosilica, product number S104596, particle size 30 nm, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0047] 3-Aminopropyltriethoxysilane, CAS No. 919-30-2, was purchased from Shanghai MacLean Biochemical Technology Co., Ltd.

[0048] Example 1

[0049] The present embodiment provides a one-component self-penetrating coating for foamed ceramics, which includes the following components, in parts by weight: 5 parts of deionized water, 10 parts of polyvinyl alcohol glue, 20 parts of pure acrylic emulsion, 25 parts of quartz sand I, 25 parts of quartz sand II, 2 parts of polycarboxylic acid water reducer, 2 parts of fungicide isothiazolinone, 4 parts of dispersant, 5 parts of wetting agent and 1.8 parts of defoaming agent (1.2 parts of polydimethylsiloxane and 0.6 parts of tributyl phosphate).

[0050] Preparation of the polyvinyl alcohol glue: in parts by weight, 100 parts of deionized water and 20 parts of acetone are mixed evenly, and then 5 parts of sodium carboxymethyl cellulose are added and stirred to dissolve to obtain a sodium carboxymethyl cellulose solution; 10 parts of polyvinyl alcohol I (article number P434372, molecular weight 9000-10000) are added to 100 parts of deionized water to fully dissolve, and then 6 parts of γ-glycidyloxypropyltrimethoxysilane are added for grafting modification treatment, the temperature is controlled to 60°C, the pH is adjusted to 7.4, and the mixture is stirred at a speed of 240r / min for 100min, and then 50 parts of the sodium carboxymethyl cellulose solution are added and stirred evenly to obtain the polyvinyl alcohol glue.

[0051] Preparation of the quartz sand I: In parts by weight, 100 parts of deionized water and 100 parts of anhydrous ethanol are mixed evenly, then 25 parts of 600-mesh quartz sand are added and ultrasonically dispersed evenly, and then 5 parts of hexadecyltrimethylammonium bromide are added for hydrophobic modification treatment, the temperature is controlled at 70°C, stirred at a speed of 100 r / min for 4 hours, and vacuum dried to obtain quartz sand I.

[0052] Preparation of the quartz sand II: by weight, 25 parts of 100 mesh quartz sand are washed with deionized water for 5 times, dried, then added to 50 parts of a hydrochloric acid solution with a mass concentration of 30% and soaked for 40 minutes, washed with water until the pH is neutral, and dried to obtain acid-treated quartz sand; 25 parts of the acid-treated quartz sand are added to a sodium hydroxide solution with a mass concentration of 10% and soaked for 50 minutes, washed with water until the pH is neutral, dried to obtain pretreated quartz sand, and then dispersed in a mixed solution of 20 parts of deionized water and 180 parts of anhydrous ethanol, 10 parts of nano-silicon dioxide are added and stirred evenly, and then 12 parts of 3-aminopropyltriethoxysilane are added for surface functionalization treatment, the pH is adjusted to 4.8, treated at 60°C for 2 hours, and vacuum dried to obtain quartz sand II.

[0053] Example 2

[0054] The present embodiment provides a one-component self-penetrating coating for foamed ceramics, which includes the following components, in parts by weight: 3 parts of deionized water, 8 parts of polyvinyl alcohol glue, 16 parts of pure acrylic emulsion, 20 parts of quartz sand I, 20 parts of quartz sand II, 1 part of polycarboxylic acid water reducer, 1 part of fungicide isothiazolinone, 2 parts of dispersant, 3 parts of wetting agent and 1.2 parts of defoaming agent (0.6 parts of polydimethylsiloxane and 0.6 parts of tributyl phosphate).

[0055] Preparation of the polyvinyl alcohol glue: in parts by weight, 80 parts of deionized water and 16 parts of acetone are mixed evenly, and then 3 parts of sodium carboxymethyl cellulose are added and stirred to dissolve to obtain a sodium carboxymethyl cellulose solution; 8 parts of polyvinyl alcohol I (article number P434372, molecular weight 9000-10000) are added to 90 parts of deionized water to fully dissolve, and then 2 parts of γ-glycidyloxypropyltrimethoxysilane are added for grafting modification treatment, the temperature is controlled to 50° C., the pH is adjusted to 7.2, and the mixture is stirred at a speed of 200 r / min for 120 minutes, and then 40 parts of the sodium carboxymethyl cellulose solution are added and stirred evenly to obtain the polyvinyl alcohol glue.

[0056] Preparation of the quartz sand I: In parts by weight, 90 parts of deionized water and 90 parts of anhydrous ethanol are mixed evenly, and then 20 parts of 600 mesh quartz sand are added and ultrasonically dispersed evenly, and then 3 parts of hexadecyltrimethylammonium bromide are added for hydrophobic modification treatment, the temperature is controlled at 60°C, stirred at a speed of 80r / min for 6h, and vacuum dried to obtain quartz sand I.

[0057] Preparation of the quartz sand II: by weight, 20 parts of 100 mesh quartz sand are washed 3 times with deionized water, dried, then added to 40 parts of hydrochloric acid solution with a mass concentration of 26% and soaked for 40 minutes, washed with water until the pH is neutral, and dried to obtain acid-treated quartz sand; 20 parts of the acid-treated quartz sand are added to a sodium hydroxide solution with a mass concentration of 8% and soaked for 50 minutes, washed with water until the pH is neutral, dried to obtain pretreated quartz sand, and then dispersed in a mixed solution of 10 parts of deionized water and 190 parts of anhydrous ethanol, 6 parts of nano-silicon dioxide are added and stirred evenly, and then 6 parts of 3-aminopropyltriethoxysilane are added for surface functionalization treatment, the pH is adjusted to 4.4, treated at 50°C for 4 hours, and vacuum dried to obtain quartz sand II.

[0058] Example 3

[0059] The present embodiment provides a one-component self-penetrating coating for foamed ceramics, which includes the following components, in parts by weight: 4 parts of deionized water, 9 parts of polyvinyl alcohol glue, 18 parts of pure acrylic emulsion, 22 parts of quartz sand I, 22 parts of quartz sand II, 1.5 parts of polycarboxylic acid water reducer, 1.5 parts of fungicide isothiazolinone, 3 parts of dispersant, 4 parts of wetting agent and 1.5 parts of defoaming agent (0.9 parts of polydimethylsiloxane and 0.6 parts of tributyl phosphate).

[0060] Preparation of the polyvinyl alcohol glue: in parts by weight, 90 parts of deionized water and 18 parts of acetone are mixed evenly, and then 4 parts of sodium carboxymethyl cellulose are added and stirred to dissolve to obtain a sodium carboxymethyl cellulose solution; 9 parts of polyvinyl alcohol I (article number P434372, molecular weight 9000-10000) are added to 95 parts of deionized water to fully dissolve, and then 4 parts of γ-glycidyloxypropyltrimethoxysilane are added for grafting modification treatment, the temperature is controlled to 55° C., the pH is adjusted to 7.3, and the mixture is stirred at a speed of 220 r / min for 110 minutes, and then 45 parts of the sodium carboxymethyl cellulose solution are added and stirred evenly to obtain the polyvinyl alcohol glue.

[0061] Preparation of the quartz sand I: In parts by weight, 95 parts of deionized water and 95 parts of anhydrous ethanol are mixed evenly, and then 22 parts of 600-mesh quartz sand are added and ultrasonically dispersed evenly, and then 4 parts of hexadecyltrimethylammonium bromide are added for hydrophobic modification treatment, the temperature is controlled at 65° C., stirred at a speed of 90 r / min for 5 hours, and vacuum dried to obtain quartz sand I.

[0062] Preparation of the quartz sand II: by weight, 22 parts of 100 mesh quartz sand are washed 4 times with deionized water, dried, then added to 45 parts of a hydrochloric acid solution with a mass concentration of 28% and soaked for 35 minutes, washed with water until the pH is neutral, and dried to obtain acid-treated quartz sand; 22 parts of the acid-treated quartz sand are added to a sodium hydroxide solution with a mass concentration of 9% and soaked for 45 minutes, washed with water until the pH is neutral, dried to obtain pretreated quartz sand, and then dispersed in a mixed solution of 15 parts of deionized water and 185 parts of anhydrous ethanol, 8 parts of nano-silicon dioxide are added and stirred evenly, and then 8 parts of 3-aminopropyltriethoxysilane are added for surface functionalization treatment, the pH is adjusted to 4.6, treated at 55°C for 3 hours, and vacuum dried to obtain quartz sand II.

[0063] Comparative Example 1

[0064] This comparative example provides a method for preparing a self-penetrating coating, which differs from Example 1 in that a polyvinyl alcohol I solution with a mass concentration of 10% is used instead of the polyvinyl alcohol glue.

[0065] Comparative Example 2

[0066] This comparative example provides a method for preparing a self-penetrating coating, which is different from Example 1 in that polyvinyl alcohol II is used instead of polyvinyl alcohol I to prepare polyvinyl alcohol glue.

[0067] Comparative Example 3

[0068] This comparative example provides a method for preparing a self-penetrating coating, which differs from Example 1 in that commercially available 600-mesh quartz sand (purchased from Guangdong Yuanlei) is used instead of quartz sand I.

[0069] Comparative Example 4

[0070] This comparative example provides a method for preparing a self-penetrating coating, which differs from Example 1 in that commercially available 100-mesh quartz sand (purchased from Chongqing Qianyi) is used instead of quartz sand II.

[0071] Comparative Example 5

[0072] This comparative example provides a method for preparing a self-penetrating coating, which is different from Example 1 in that the amount of polydimethylsiloxane in the defoaming agent is changed to 1.6 parts, and the amount of tributyl phosphate is changed to 0.2 parts.

[0073] Comparative Example 6

[0074] This comparative example provides a method for preparing a self-penetrating coating, which is different from Example 1 in that the amount of polydimethylsiloxane in the defoaming agent is changed to 0.6 parts, and the amount of tributyl phosphate is changed to 1.2 parts.

[0075] The coatings prepared in the above examples and comparative examples were tested for performance with reference to "JC / T 984-2011 Polymer Cement Waterproof Mortar". The performance test results are shown in Table 1:

[0076] Table 1 Performance test results

[0077]

[0078] It can be seen from the above performance test results that Examples 1-3 have good effects, with a 28d compressive strength of 19.49-19.56 MPa, a 28d bonding strength of 1.33-1.36 MPa, a water absorption of 5.21-5.28%, and a shrinkage of 0.215-0.219%; this is because the present invention modifies the coating components, first grafting and modifying polyvinyl alcohol, then mixing it with sodium carboxymethyl cellulose to prepare polyvinyl alcohol glue, and then using it in combination with two different modified quartz sands, which effectively improves the compressive strength and bonding strength of the coating, while reducing the water absorption and shrinkage.

[0079] Compared with Example 1, Comparative Example 1 uses a 10% mass concentration of polyvinyl alcohol I solution to replace polyvinyl alcohol glue, and the compressive strength and bonding strength are reduced, the water absorption rate is increased, and the shrinkage rate is increased; Compared with Example 1, Comparative Example 2 uses polyvinyl alcohol II to replace polyvinyl alcohol I to prepare polyvinyl alcohol glue. Since the molecular weight of polyvinyl alcohol II is too large, the modification effect is not good, the compressive strength and bonding strength are reduced, the water absorption rate is increased, and the shrinkage rate is increased; Compared with Example 1, Comparative Example 3 uses commercially available 600 mesh quartz sand (purchased from Guangdong Yuanlei) to replace quartz sand I, and the compressive strength and bonding strength are reduced, the water absorption rate is increased, and the shrinkage rate is increased; Compared with Example 1, Comparative Example 4 uses commercially available 100 Mesh quartz sand (purchased from Chongqing Qianyi) replaces quartz sand II, the compressive strength and bonding strength decrease, the water absorption rate increases, and the shrinkage rate increases; compared with Example 1, the amount of polydimethylsiloxane in the defoamer of Comparative Example 5 is changed to 1.6 parts, and the amount of tributyl phosphate is changed to 0.2 parts, then the amount of polydimethylsiloxane is too much, and the compounding effect is not good, so the compressive strength and bonding strength decrease, the water absorption rate increases, and the shrinkage rate increases; compared with Example 1, the amount of polydimethylsiloxane in the defoamer of Comparative Example 6 is changed to 0.6 parts, and the amount of tributyl phosphate is changed to 1.2 parts, then the amount of polydimethylsiloxane is too little, and the compounding effect is not good, so the compressive strength and bonding strength decrease, the water absorption rate increases, and the shrinkage rate increases.

Claims

1. A one-component self-penetrating coating for foamed ceramics, characterized in that: The composition comprises the following components in parts by weight: 3 to 5 parts of deionized water, 8 to 10 parts of polyvinyl alcohol glue, 16 to 20 parts of pure acrylic emulsion, 40 to 50 parts of quartz sand, 1 to 2 parts of water reducing agent, 1 to 2 parts of bactericide, 2 to 4 parts of dispersant, 3 to 5 parts of wetting agent and 1.2 to 1.8 parts of defoaming agent; The preparation method of the polyvinyl alcohol glue comprises: mixing 80 to 100 parts of deionized water and 16 to 20 parts of acetone by weight, and then adding 3 to 5 parts of sodium carboxymethyl cellulose and stirring to dissolve to obtain a sodium carboxymethyl cellulose solution; adding 8 to 10 parts of commercially available polyvinyl alcohol to 90 to 100 parts of deionized water to fully dissolve, and then adding 2 to 6 parts of γ-glycidyloxypropyltrimethoxysilane for grafting modification treatment, and then adding 40 to 50 parts of the sodium carboxymethyl cellulose solution and stirring to obtain the polyvinyl alcohol glue.

2. A one-component self-penetrating coating for foamed ceramics according to claim 1, characterized in that: The graft modification treatment conditions include: controlling the temperature to 50-60° C., adjusting the pH to 7.2-7.4, and stirring at a speed of 200-240 r / min for 100-120 min.

3. The one-component self-penetrating coating for foamed ceramics according to claim 1, characterized in that: The molecular weight of the commercially available polyvinyl alcohol is 5,000 to 10,000.

4. The one-component self-penetrating coating for foamed ceramics according to claim 1, characterized in that: The 40 to 50 parts of quartz sand include 20 to 25 parts of quartz sand I and 20 to 25 parts of quartz sand II.

5. The one-component self-penetrating coating for foamed ceramics according to claim 4, characterized in that: The preparation method of the quartz sand I comprises: mixing 90 to 100 parts of deionized water and 90 to 100 parts of anhydrous ethanol by weight, then adding 20 to 25 parts of 600-mesh quartz sand for ultrasonic dispersion, and then adding 3 to 5 parts of hexadecyltrimethylammonium bromide for hydrophobic modification to obtain quartz sand I.

6. The one-component self-penetrating coating for foamed ceramics according to claim 5, characterized in that: The conditions of the hydrophobic modification treatment include: controlling the temperature to 60-70° C., stirring at a speed of 80-100 r / min for 4-6 hours, and vacuum drying.

7. The one-component self-penetrating coating for foamed ceramics according to claim 4, characterized in that: The preparation method of the quartz sand II comprises: pre-treating 20 to 25 parts of 100-mesh quartz sand by weight, dispersing the pre-treating mixture in a mixture of 10 to 20 parts of deionized water and 180 to 190 parts of anhydrous ethanol, adding 6 to 10 parts of nano silicon dioxide and stirring the mixture evenly, and then adding 6 to 12 parts of 3-aminopropyltriethoxysilane for surface functionalization treatment to obtain quartz sand II.

8. The one-component self-penetrating coating for foamed ceramics according to claim 7, characterized in that: The pretreatment conditions include: washing 20 to 25 parts of 100-mesh quartz sand with deionized water for 3 to 5 times, drying, then adding to 40 to 50 parts of a hydrochloric acid solution with a mass concentration of 26 to 30% and soaking for 30 to 40 minutes, washing with water until the pH value is neutral, and drying to obtain acid-treated quartz sand; adding 20 to 25 parts of the acid-treated quartz sand to a sodium hydroxide solution with a mass concentration of 8 to 10% and soaking for 40 to 50 minutes, washing with water until the pH value is neutral, and drying to obtain pretreated quartz sand.

9. The one-component self-penetrating coating for foamed ceramics according to claim 1, characterized in that: The defoaming agent is polydimethylsiloxane and tributyl phosphate; the mass ratio of polydimethylsiloxane to tributyl phosphate in the defoaming agent is (1-2):

1.

10. A method for preparing a single-component self-penetrating coating for foamed ceramics according to any one of claims 1 to 9, characterized in that: The steps include: In parts by weight, 3-5 parts of deionized water, 8-10 parts of polyvinyl alcohol glue and 16-20 parts of pure acrylic emulsion are mixed and stirred for 40-60 minutes, and then 40-50 parts of quartz sand, 1-2 parts of water reducer, 1-2 parts of fungicide, 2-4 parts of dispersant, 3-5 parts of wetting agent and 1.2-1.8 parts of defoamer are added and stirred to obtain a single-component self-penetrating coating for foamed ceramics.

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