Geopolymer gel antique exterior wall plastering mortar and preparation method thereof

Abstract

The application discloses a geopolymer gel antique exterior wall plastering mortar and a preparation method thereof. The geopolymer gel antique exterior wall plastering mortar is composed of the following components in mass: 75-85 parts of metakaolin-based geopolymer gel; and 15-25 parts of a mixture of molybdenum sulfide salt / tungsten sulfide salt. The preparation method comprises the following steps: preparing the metakaolin-based geopolymer gel; preparing the flaky stacked mixture of molybdenum sulfide salt / tungsten sulfide salt; adding the mixture of molybdenum sulfide salt / tungsten sulfide salt into the metakaolin-based geopolymer gel; and high-speed dispersing to obtain the metakaolin-based geopolymer gel antique exterior wall plastering mortar containing molybdenum sulfide salt / tungsten sulfide salt. The mixture of molybdenum sulfide salt / tungsten sulfide salt is creatively added into the geopolymer gel, and the obtained metakaolin-based geopolymer gel antique exterior wall plastering mortar can effectively improve the mechanical properties and solve the problems of color difference and wear resistance.

Description

Technical Field

[0001] This invention relates to a building mortar, specifically a plastering mortar, and more particularly to an antique-style exterior wall plastering mortar containing metakaolin-based polymer gel and its preparation method. Background Technology

[0002] Plastering mortar is a type of mortar applied to the surface of buildings or building components, serving both to protect the base layer and to fulfill functional requirements. In particular, the plastering mortar used for antique-style exterior walls also functions as an antique-style finish.

[0003] Geopolymers are inorganic polymer cementitious materials with a three-dimensional network structure composed of AlO4 and SiO4 tetrahedral structural units. They possess excellent mechanical properties and resistance to acids, alkalis, fire, and high temperatures. However, geopolymers exhibit relatively low mechanical properties, limiting their use in mortars.

[0004] Geopolymer gel materials based on kaolin have the characteristics of being natural and environmentally friendly, but their disadvantages include low strength, poor water resistance and weather resistance. When used in plastering mortar to make antique-style finishes, they have disadvantages such as large color difference and poor washability.

[0005] Therefore, when using geopolymers to replace cement-based materials to develop antique-style exterior wall plastering mortar, it is necessary to consider both workability and mechanical properties, and solve the problems of color difference and wear resistance. Summary of the Invention

[0006] The objective of this invention is to provide a geopolymer gel-based antique-style exterior wall plastering mortar to improve its mechanical strength, thereby giving it wear resistance, water resistance, low segregation, and ultra-low color difference. Another objective of this invention is to provide a method for preparing this geopolymer gel-based antique-style exterior wall plastering mortar.

[0007] To achieve the above-mentioned objectives, the technical solution adopted by the present invention is: a polymer gel antique exterior wall plastering mortar, which is composed of the following components by mass: 75-85 parts of metakaolin-based polymer gel; 15-25 parts of thiomolybdate / thiotungstate mixture.

[0008] In the above technical solution, the thiomolybdate / thiotungstate mixture is obtained by dispersing and reacting the following raw materials in water. By mass, the reaction raw materials include 10-20 parts of silica sol; 2-5 parts of a mixture of MoS2 and WS2; and 5-10 parts of heptadecafluorodecyltrimethoxysilane.

[0009] The silica sol has a solid content of 28-32%, a pH value of 9-10, and an average particle size of 8-25 nm.

[0010] The MoS2 and WS2 mixture is a mixture of 50-80 nm MoS2 and WS2 in a mass ratio of 1:0.2-0.3, with a mass fraction greater than 99%.

[0011] The mass fraction of heptadecafluorodecyltrimethoxysilane is greater than 96%.

[0012] In the above technical solution, the metakaolin-based polymer gel is a mixture of four materials: metakaolin, slag, alkali activator, and polycarboxylate superplasticizer.

[0013] The weight ratio of metakaolin, slag, alkali activator lithium carbonate, and polycarboxylate superplasticizer in the metakaolin-based polymer gel is 2-4:2-5:0.5-3:3-8.

[0014] In the above technical solution, the thiomolybdate / thiotungstate mixture utilizes the MoS2 / WS2 lubrication mechanism. MoS2 / WS2 has a two-dimensional structure similar to graphene, allowing it to disperse between kaolin particles, thereby improving the lubricity between clay particles and reducing viscosity and homogenizing the geopolymer. The combined use of the thiomolybdate / thiotungstate mixture and polycarboxylate superplasticizer effectively reduces the water consumption of the geopolymer, thus improving its mechanical strength, water resistance, and abrasion resistance. It also significantly improves the uniformity of the geopolymer, reducing delamination and color difference. Thiomolybdate / thiotungstate helps the superplasticizer quickly penetrate the kaolin surface and enter its interlayer structure, playing a positive role in maintaining the workability and flowability of the geopolymer. Thiomolybdate / thiotungstate is a very fine powder. If it is added directly to the geopolymer, it will form agglomerates and reduce the effectiveness of the product. This invention solves the above problem by first mixing and dispersing thiomolybdate / thiotungstate, silica sol and heptadecafluorodecyltrimethoxysilane at high speed to prepare a mixed solution, and then compounding it with polycarboxylate superplasticizer.

[0015] To achieve another objective of this invention, a method for preparing geopolymer gel-based antique-style exterior wall plastering mortar is provided, comprising the following steps:

[0016] Step 1: Preparation of metakaolin-based polymer gel

[0017] S1: Add metakaolin, slag, alkali activator, and polycarboxylate superplasticizer to the mixer in sequence and stir evenly to obtain metakaolin-based polymer powder;

[0018] S2: Add water to the metakaolin-based polymer powder, the mass ratio of metakaolin-based polymer powder to water is 1:0.3, then stir evenly at 80-90℃, and obtain metakaolin-based polymer gel after cooling.

[0019] Step 2: Preparation of sheet-like stacked thiomolybdate / thiotungstate mixtures

[0020] S3. Add the mixture of MoS2 and WS2 and water to a container and disperse until a uniform slurry is formed;

[0021] S4. The slurry obtained in S3 is refluxed and heated to the reaction temperature under stirring. Silica sol is added at a uniform rate. After the addition is complete, heptadecafluorodecyltrimethoxysilane is added, and the reaction is continued under reflux and heating under stirring.

[0022] S5. Stop heating the slurry obtained in S4 while stirring and refluxing, allow it to cool naturally to room temperature, and then stop stirring to obtain a thiomolybdate / thiotungstate mixed dispersion.

[0023] Step 3: Add the thiomolybdate / thiotungstate mixed dispersion to the metakaolin-based polymer gel and disperse at high speed to obtain a metakaolin-based polymer gel antique exterior wall plastering mortar containing thiomolybdate / thiotungstate.

[0024] In the above technical solution, the geopolymer gel must pass through a 325-mesh sieve with a residue of less than 3%. This meets the requirements for stirring and dispersion, allowing for precise control of the stirring time, and thus precise control of the color difference value of the antique exterior wall plastering mortar.

[0025] In the above technical solution, in step S3, the dispersion includes two steps: high-speed stirring and ultra-dispersion performed sequentially. During high-speed stirring, the rotation speed is 1200-1400 rpm and the dispersion time is 30-40 minutes. The ultrasonic dispersion time is also 30-40 minutes.

[0026] In S4, the reaction temperature is 45-50℃, the stirring speed is 400-600 rpm, the silica sol dropping time is controlled at 20-25 minutes, and after adding heptadecafluorodecyltrimethoxysilane, the reaction continues for 50-60 minutes.

[0027] In S5, the stirring speed is 300-400 rpm.

[0028] In step three, the high-speed dispersion time is 30 minutes, and the rotation speed is 800 rpm.

[0029] In the above technical solution, in step one, the weight ratio of metakaolin, slag, alkali activator lithium carbonate, and polycarboxylate superplasticizer is 2-4:2-5:0.5-3:3-8.

[0030] In step two, by mass, there are 2-5 parts of the mixture of MoS2 and WS2; 10-20 parts of silica sol; and 5-10 parts of heptadecafluorodecyltrimethoxysilane. The mixture of MoS2 and WS2 is a mixture of 50-80 nm MoS2 and WS2 in a mass ratio of 1:0.2-0.3.

[0031] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0032] 1. This invention creatively incorporates a thiomolybdate / thiotungstate mixture into the geopolymer gel, resulting in a metakaolin-based polymer gel antique-style exterior wall plastering mortar that effectively improves mechanical properties and solves problems of color difference and wear resistance.

[0033] 2. The sulfur-containing molybdate / thiotungstate-metakaolin-based polymer gel antique-style exterior wall plastering mortar prepared by this invention has a compressive strength ≥40MPa and a bond strength ≥2MPa, ensuring the product's strength and durability. The mortar segregation value is ≤1mm, far below the standard requirement of ≤30mm. This ensures the homogeneity of the mortar, resulting in excellent finishing and workability for the entire system.

[0034] 3. The sulfur-containing molybdate / thiotungstate-metakaolin-based polymer gel antique exterior wall plastering mortar prepared by this invention has a color difference value ΔE≤0.1, which is far lower than the requirement of color difference value ΔE≤0.8 for plain decorative surfaces, ensuring that the mortar has a uniform finish and small color difference after hardening.

[0035] 4. The sulfur-containing molybdate / thiotungstate-metakaolin-based polymer gel antique exterior wall plastering mortar prepared by this invention has a softening coefficient ≥0.8, ensuring that the mortar can meet the requirements of various construction parts and can be used for exterior walls, interior walls, bathrooms and balconies. Its water resistance meets the design requirements.

[0036] 5. The sulfur-containing molybdate / thiotungstate-metakaolin-based polymer gel antique exterior wall plastering mortar prepared by this invention shows no wear marks on the surface after 50,000 washes, ensuring that the mortar can adapt to the requirements of various construction parts and that its wear resistance meets the design requirements.

[0037] 6. The sulfur-containing molybdate / thiotungstate-metakaolin-based polymer gel antique exterior wall plastering mortar prepared by this invention can be used on the construction site without secondary mixing. It is simple and convenient to use and has stable quality. Detailed Implementation

[0038] The present invention will be further described below with reference to embodiments:

[0039] Example 1: An antique-style exterior wall plastering mortar, composed of the following components by weight: 80 parts of metakaolin-based polymer gel; 20 parts of a thiomolybdate / thiotungstate mixture. In the metakaolin-based polymer gel, the weight ratio of metakaolin, slag, alkali activator, and water-reducing agent is 3:3:2:4.

[0040] Preparation method:

[0041] Step 1: Preparation of metakaolin-based polymer gel

[0042] S1: Add metakaolin, slag, alkali activator, and Fock C1039 polycarboxylate superplasticizer (commercially available) to a mixer in the specified proportions and stir until homogeneous to obtain metakaolin-based polymer powder.

[0043] S2: Add water to the metakaolin-based polymer powder, with a mass ratio of metakaolin-based polymer powder to water of 1:0.32, and then stir evenly at 80-90℃. After cooling, a metakaolin-based polymer gel is obtained.

[0044] Step 2: Prepare a sheet-like stacked thiomolybdate / thiotungstate mixed dispersion, as follows:

[0045] S3. Add measured amounts of water and nano-sized MoS2 / WS2 to a container and disperse at high speed to form a uniform slurry; the stirring speed is 1200-1400 rpm, the dispersion time is 30-40 minutes, the mass ratio of molybdenum disulfide to tungsten disulfide is 1:0.2-0.3, and the fineness of the powder is 50-80 nm.

[0046] S4. Disperse the slurry obtained in S3 using ultrasound for 30-40 minutes;

[0047] S5. The slurry obtained in S4 is refluxed and heated to the reaction temperature (45-50℃) under stirring. The stirring speed is 400-600 rpm. Silica sol is added at a uniform rate, and the addition time is controlled at 20-25 minutes. After the addition is completed, heptadecafluorodecyltrimethoxysilane is added, and the reaction is continued under stirring under reflux for 50-60 minutes. The composition is as follows: 20 parts silica sol; 3 parts a mixture of MoS2 and WS2; and 5 parts heptadecafluorodecyltrimethoxysilane.

[0048] S6. Stop heating the slurry obtained in S5 while stirring and refluxing. The stirring speed is 300-400 rpm. Allow it to cool naturally to room temperature and then stop stirring to obtain a thiomolybdate / thiotungstate mixed dispersion.

[0049] Step 3: Weigh the other components according to the mass ratio, add the weighed thiomolybdate / thiotungstate mixed dispersion to the geopolymer gel, and disperse again at high speed for 30 minutes at a speed of 800 rpm. This yields the desired thiomolybdate / thiotungstate-metakaolin-based polymer gel antique-style exterior wall plastering mortar.

[0050] Example 2: An antique-style exterior wall plastering mortar, composed of the following components by weight: 78 parts of metakaolin-based polymer gel; 22 parts of a thiomolybdate / thiotungstate mixture. The metakaolin-based polymer gel has a weight ratio of metakaolin, slag, alkali activator, and water-reducing agent of 2:2:2.5:3.5.

[0051] Preparation method:

[0052] Step 1: Preparation of metakaolin-based polymer gel

[0053] S1: Add metakaolin, slag, alkali activator, and Fock C1039 polycarboxylate superplasticizer (commercially available) to a mixer in the specified proportions and stir until homogeneous to obtain metakaolin-based polymer powder.

[0054] S2: Add the water to the metakaolin-based polymer powder, the mass ratio of metakaolin-based polymer powder to water is 1:0.31, and then stir evenly at 80-90℃. After cooling, a metakaolin-based polymer gel is obtained.

[0055] Step 2: Prepare a thiomolybdate / thiotungstate mixed dispersion according to the method in Example 1.

[0056] Step 3: Weigh the other components according to the mass ratio, add the weighed thiomolybdate / thiotungstate mixed dispersion to the geopolymer gel, and disperse again at high speed for 30 minutes at a speed of 800 rpm. This yields the desired thiomolybdate / thiotungstate-metakaolin-based polymer gel antique-style exterior wall plastering mortar.

[0057] Example 3: An antique-style exterior wall plastering mortar, composed of the following components by weight: 75 parts metakaolin-based polymer gel; 25 parts thiomolybdate / thiotungstate mixture. The metakaolin-based polymer gel is composed of metakaolin, slag, alkali activator, and water-reducing agent in a weight ratio of 4:5:2:5.

[0058] Preparation method:

[0059] Step 1: Preparation of metakaolin-based polymer gel

[0060] S1: Add metakaolin, slag, alkali activator, and Fock C1039 polycarboxylate superplasticizer (commercially available) to a mixer in the specified proportions and stir until homogeneous to obtain metakaolin-based polymer powder.

[0061] S2: Add the water to the metakaolin-based polymer powder, the mass ratio of metakaolin-based polymer powder to water is 1:0.28, and then stir evenly at 80-90℃. After cooling, a metakaolin-based polymer gel is obtained.

[0062] Step 2: Prepare a thiomolybdate / thiotungstate mixed dispersion according to the method in Example 1.

[0063] Step 3: Weigh the other components according to the mass ratio, add the weighed thiomolybdate / thiotungstate mixed dispersion to the geopolymer gel, and disperse again at high speed for 30 minutes at a speed of 800 rpm. This yields the desired thiomolybdate / thiotungstate-metakaolin-based polymer gel antique-style exterior wall plastering mortar.

[0064] Control group 1: Contains 10 parts of thiomolybdate / thiotungstate mixed dispersion

[0065] An antique-style exterior wall plastering mortar, by weight, consists of the following components: 90 parts metakaolin-based polymer gel; 10 parts thiomolybdate / thiotungstate mixture. To achieve the same flowability and workability, the mass ratio of metakaolin-based polymer powder to water is 1:0.4, and other preparation methods are the same as in Example 1.

[0066] Control group 2: Contains 5 parts of thiomolybdate / thiotungstate mixed dispersion

[0067] An antique-style exterior wall plastering mortar, by weight, consists of the following components: 95 parts metakaolin-based polymer gel; 5 parts thiomolybdate / thiotungstate mixture. To achieve the same flowability and workability, the mass ratio of metakaolin-based polymer powder to water is 1:0.45, and other preparation methods are the same as in Example 1.

[0068] Comparative Group 3: Dispersions without thiomolybdate / thiotungstate mixtures

[0069] An antique-style exterior wall plastering mortar, by weight, consists of the following components: 100 parts of metakaolin-based polymer gel; free of thiomolybdate / thiotungstate dispersion. To achieve the same flowability and workability, the mass ratio of metakaolin-based polymer powder to water is 1:0.5, and other preparation methods are the same as in Example 1.

[0070] Comparative Group 4: Comparative experiment of Example 1 using 30nm MoS2 / WS2

[0071] An antique-style exterior wall plastering mortar, by weight, comprises the following components: 80 parts of metakaolin-based polymer gel; and 20 parts of a thiomolybdate / thiotungstate mixture. In the metakaolin-based polymer gel, the weight ratio of metakaolin, slag, alkali activator, and water-reducing agent is 3:3:2:4. The MoS2 / WS2 nanoparticles have a diameter of 30 nm. Other preparation methods are the same as in Example 1.

[0072] Comparative Group 5: Comparative experiment of Example 1 using 90nm MoS2 / WS2

[0073] An antique-style exterior wall plastering mortar, by weight, comprises the following components: 80 parts of metakaolin-based polymer gel; and 20 parts of a thiomolybdate / thiotungstate mixture. In the metakaolin-based polymer gel, the weight ratio of metakaolin, slag, alkali activator, and water-reducing agent is 3:3:2:4. The MoS2 / WS2 nanoparticles have a diameter of 90 nm. Other preparation methods are the same as in Example 1.

[0074] The performance tests of antique-style exterior wall plastering mortar mainly include compressive strength, flexural strength, bond strength, segregation, color difference, softening coefficient, etc., and the requirements comply with GB / T 25181-2019 "Premixed Mortar", GB / T 20473-2021 "Building Thermal Insulation Mortar", GB / T 6688-2008 "Determination of Relative Strength and Color Difference of Dyes", and GB / T 9266-2009 "Determination of Scrub Resistance of Building Coatings".

[0075] The test results are as follows:

[0076] Table 1:

[0077]

[0078] The above embodiments and their mechanical property test results show that the antique-style exterior wall plastering mortar and its preparation method of the present invention can meet the construction requirements, and all indicators are superior to the standards. The comparative experiments show that if the amount of thiomolybdate / thiotungstate mixed dispersion is less than that required by the present invention, the performance is significantly reduced and cannot meet the quality requirements; if thiomolybdate / thiotungstate mixed dispersions with other nanoparticle sizes are used, the performance also decreases significantly.

[0079] As can be seen from the above embodiments, the antique-style exterior wall plastering mortar prepared by this invention can be used on-site without secondary mixing, making it simple and convenient to use, and with stable quality. The compressive strength is ≥40MPa, and the bond strength is ≥2MPa, ensuring the product's strength and durability. The mortar segregation value is ≤1mm, far below the standard requirement of ≤30mm, ensuring the mortar's homogeneity and resulting in excellent finishing and construction performance. The color difference value ΔE ≤0.1 is far below the requirement of ΔE ≤0.8 for solid color decorative surfaces, ensuring a uniform finish and minimal color difference after hardening. The softening coefficient is ≥0.8, ensuring that the geopolymer mortar can adapt to the requirements of various construction areas, suitable for exterior walls, interior walls, bathrooms, and balconies, and its water resistance meets design requirements.

[0080] Tests show that the antique-style exterior wall plastering mortar prepared by this invention shows no wear marks on the surface after 50,000 washes, ensuring that the mortar can adapt to the requirements of various construction parts and that its wear resistance meets the design requirements.

Claims

1. A geopolymer gel-based antique-style exterior wall plastering mortar, characterized in that, By weight, it consists of the following components: 75-85 parts metakaolin-based polymer gel; 15-25 parts mixture; The metakaolin-based polymer gel contains a polycarboxylate superplasticizer. The reaction raw materials of the mixture, by mass, include 10-20 parts of silica sol; 2-5 parts of a mixture of MoS2 and WS2; and 5-10 parts of heptadecafluorodecyltrimethoxysilane. The MoS2 and WS2 mixture is a mixture of 50-80 nm MoS2 and WS2 in a mass ratio of 1:0.2-0.

3. The mixture was prepared using the following method: S3. Add the mixture of MoS2 and WS2 and water to a container and disperse until a uniform slurry is formed; S4. The slurry obtained in S3 is refluxed and heated to the reaction temperature under stirring. Silica sol is added at a uniform rate. After the addition is complete, heptadecafluorodecyltrimethoxysilane is added, and the reaction is continued under reflux and heating under stirring. S5. Stop heating the slurry obtained in S4 while stirring and refluxing, allow it to cool naturally to room temperature, stop stirring, and obtain a mixture.

2. The geopolymer gel antique exterior wall plastering mortar according to claim 1, characterized in that: The silica sol has a solid content of 28-32%, a pH value of 9-10, and an average particle size of 8-25 nm.

3. The geopolymer gel antique exterior wall plastering mortar according to claim 1, characterized in that: The metakaolin-based polymer gel is a mixture of four materials: metakaolin, slag, alkali activator, and polycarboxylate superplasticizer.

4. The geopolymer gel antique exterior wall plastering mortar according to claim 3, characterized in that: The weight ratio of metakaolin, slag, alkali activator lithium carbonate, and polycarboxylate superplasticizer in the metakaolin-based polymer gel is 2-4:2-5:0.5-3:3-8.

5. The method for preparing the geopolymer gel antique exterior wall plastering mortar according to claim 1, characterized in that, Includes the following steps: Step 1: Preparation of metakaolin-based polymer gel S1: Add metakaolin, slag, alkali activator, and polycarboxylate superplasticizer to the mixer in sequence and stir evenly to obtain metakaolin-based polymer powder; S2: Add water to the metakaolin-based polymer powder, the mass ratio of metakaolin-based polymer powder to water is 1:0.3, then stir evenly at 80-90℃, and obtain metakaolin-based polymer gel after cooling. Step 2: Prepare a mixture of stacked sheets S3. Add the mixture of MoS2 and WS2 and water to a container and disperse until a uniform slurry is formed; S4. The slurry obtained in S3 is refluxed and heated to the reaction temperature under stirring. Silica sol is added at a uniform rate. After the addition is complete, heptadecafluorodecyltrimethoxysilane is added, and the reaction is continued under reflux and heating under stirring. S5. Stop heating the slurry obtained in S4 while stirring and refluxing, allow it to cool naturally to room temperature, stop stirring, and obtain a mixture; Step 3: Add the mixture to the metakaolin base polymer gel and disperse at high speed to obtain the geopolymer gel antique exterior wall plastering mortar.

6. The method for preparing geopolymer gel antique-style exterior wall plastering mortar according to claim 5, characterized in that: In S3, the dispersion includes two steps: high-speed stirring and ultrasonic dispersion performed sequentially. During high-speed stirring, the rotation speed is 1200-1400 rpm and the dispersion time is 30-40 minutes. The ultrasonic dispersion time is also 30-40 minutes. In S4, the reaction temperature is 45-50℃, the stirring speed is 400-600 rpm, the silica sol dropping time is controlled at 20-25 minutes, and after adding heptadecafluorodecyltrimethoxysilane, the reaction continues for 50-60 minutes. In S5, the stirring speed is 300-400 rpm.

7. The method for preparing geopolymer gel antique-style exterior wall plastering mortar according to claim 6, characterized in that: In step three, the high-speed dispersion time is 30 minutes, and the rotation speed is 800 rpm.

8. The method for preparing geopolymer gel antique exterior wall plastering mortar according to claim 6, characterized in that: In step one, the weight ratio of metakaolin, slag, alkali activator lithium carbonate, and polycarboxylate superplasticizer is 2-4:2-5:0.5-3:3-8; In step two, by mass, there are 2-5 parts of the mixture of MoS2 and WS2; 10-20 parts of silica sol; and 5-10 parts of heptadecafluorodecyltrimethoxysilane. The mixture of MoS2 and WS2 is a mixture of 50-80 nm MoS2 and WS2 in a mass ratio of 1:0.2-0.3.

Images