A thickly-coated polymer cement waterproof coating and a preparation method thereof

Abstract

The application discloses a thick-coating type polymer cement waterproof coating and a preparation method thereof, and relates to the technical field of waterproof coatings. The thick-coating type polymer cement waterproof coating comprises a liquid component and a powder component. The liquid component comprises a styrene-acrylic emulsion, water, a defoaming agent, a thickening agent, a silane coupling agent, a wetting agent, a dispersing agent, a bactericide and a preservative. The powder component comprises Portland cement, fast-hardening cement, gypsum, sand, heavy calcium, a retarder and a water reducing agent. The application can solve the problem of coating corner cracking. By increasing the styrene-acrylic emulsion particles, the capillary pressure is reduced, so that the coating film will not crack. Meanwhile, the emulsion content is increased, and the fast-hardening cement and the thickening agent are increased, so that the problem of coating film corner cracking can be solved well. The fast-hardening cement is used in combination with the gypsum and the retarder. The drying speed is improved, the film formation will not crack, the waterproof effect of the film formation is stable, and the construction is extremely convenient.

Description

Technical Field

[0001] This invention relates to the field of waterproof coating technology, specifically to a thick-film polymer cement waterproof coating and its preparation method. Background Technology

[0002] Polymer cement waterproof coating, abbreviated as JS waterproof coating, where J stands for polymer and S stands for cement, is a two-component water-based building waterproof coating. It is made by combining organic liquids such as polyacrylate emulsion and ethylene-vinyl acetate copolymer emulsion with various additives, and inorganic powders composed of cement, sand, various additives, and inorganic fillers, through a reasonable ratio and compounding process.

[0003] Its waterproofing mechanism is to form a complete coating to block the penetration of water or the permeation of water molecules.

[0004] Polymer cementitious waterproof coatings have seen rapid development in recent years due to their simple application, high film strength, and excellent waterproofing effect, and are widely used in the building waterproofing industry. Among these, Type II products are the most widely used.

[0005] However, it has some defects in actual construction applications, such as cracking at internal corners, long drying time, easy sagging, and insufficient coating thickness on vertical surfaces. To solve the problem of cracking at internal corners, the most common solutions are to use a sealant to round the corners before construction, or to lay reinforcing materials between the layers to prevent cracking. Rounding the corners involves using sealant to round off right or acute angles. Laying reinforcing materials between the layers refers to adding reinforcing materials such as non-woven fabric or fiberglass mesh to the waterproof coating layer. This method is not only time-consuming and labor-intensive, but also requires a high level of skill from the operators, and the results are highly unpredictable. Laying reinforcing materials requires a high level of worker proficiency. Therefore, many waterproofing workers choose not to do any treatment and directly apply the waterproof coating. This construction will lead to material accumulation at internal corners and cracking of the coating, seriously affecting the waterproofing quality. Summary of the Invention

[0006] Purpose of the invention: The technical problem to be solved by the present invention is to provide a thick-film polymer cement waterproof coating and its preparation method, which solves the problem of easy cracking at the inside corners of existing coatings.

[0007] Technical solution

[0008] To solve the above problems, the technical solution provided by the present invention is as follows:

[0009] A thick-film polymer cement waterproof coating includes a liquid component and a powder component. The liquid component includes styrene-acrylic emulsion, water, defoamer, thickener, silane coupling agent, wetting agent, dispersant, bactericide, and preservative. The powder component includes ordinary Portland cement, rapid-hardening cement, gypsum, sand, heavy calcium carbonate, retarder, and water-reducing agent.

[0010] The core advantage of this thick-coat polymer cementitious waterproof coating lies in its solution to the critical technical challenge of cracking and leakage at internal corners. By endowing the coating with superior crack resistance, thick-coat adaptability, anti-sagging, and overall sealing properties at internal corners, it significantly improves the reliability and durability of waterproofing projects at complex joints, effectively eliminating the risk of leakage caused by these areas. It provides long-term, reliable waterproofing protection for buildings, while simplifying construction and reducing costs, demonstrating significant application value.

[0011] Furthermore, the mass ratio of the liquid component to the powder component is 1:1.8.

[0012] Furthermore, the average particle size of the styrene-acrylic emulsion is 350-370 nm.

[0013] Further, by mass parts, the liquid component comprises the following components: 70-100 parts of styrene-acrylic emulsion, 0-15 parts of water, 0.3-0.6 parts of defoamer, 0.1-0.3 parts of thickener, 0.2-3 parts of silane coupling agent, 0.1-0.5 parts of wetting agent, 0.1-0.5 parts of dispersant, 0.1-0.2 parts of bactericide, and 0.1-0.2 parts of preservative.

[0014] Furthermore, by mass parts, the powder composition includes the following components: 15-60 parts of ordinary Portland cement, 2-15 parts of rapid-hardening cement, 1-5 parts of gypsum, 5-30 parts of sand, 20-50 parts of heavy calcium carbonate, 0.01-0.3 parts of retarder, and 0.05-0.4 parts of water-reducing agent.

[0015] Furthermore, the content of the wetting agent and the content of the silane coupling agent are negatively correlated with the content of the water.

[0016] Furthermore, the content of the gypsum and the content of the retarder are positively correlated with the content of the rapid-hardening cement.

[0017] Furthermore, the solid content of the styrene-acrylic emulsion is 55±1%;

[0018] The defoamer is a mineral oil type;

[0019] The thickener is an associative alkali-swellable thickener;

[0020] The silane coupling agent is any one of 3-chloropropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, and acetoxypropyltrimethoxysilane;

[0021] The wetting agent is nonionic;

[0022] The dispersant is sodium polyacrylate;

[0023] The fungicide is Kathon;

[0024] The preservative is Kathon;

[0025] Ordinary Portland cement is 425 grey cement;

[0026] Rapid-hardening cement is any one of aluminate cement, sulfoaluminate cement, ferroaluminate cement, and fluoroaluminate cement;

[0027] The gypsum can be any one of gypsum, hemihydrate gypsum, or anhydrite;

[0028] The sand can be any one of river sand, manufactured sand, or quartz sand;

[0029] The precipitated calcium carbonate is 200 mesh.

[0030] The retarder is any one of sodium gluconate, carboxymethyl chitosan, sucrose stearate, sodium citrate, and tartaric acid;

[0031] The water-reducing agent is a polycarboxylate water-reducing agent.

[0032] A method for preparing a thick-film polymer cement waterproof coating involves sequentially adding a certain amount of emulsion and water to a liquid mixing tank, installing a disperser propeller, starting the disperser, maintaining a speed of 400 r / min, then adding a defoamer, wetting agent, dispersant, and silane coupling agent, stirring for 10 min, adding a thickener dropwise, stirring at 700 r / min for 10 min, adding a bactericide and preservative, continuing to stir for 10 min, then reducing the speed to 300 r / min and stirring for 5 min for mechanical defoaming to obtain the liquid components of the coating.

[0033] Ordinary Portland cement, rapid-hardening cement, gypsum, sand, heavy calcium carbonate, retarder, and water-reducing agent are added to the powder mixer in sequence. The mixer is turned on and mixed for 15 minutes. The mixture is then sieved to obtain the powder components of the coating.

[0034] Furthermore, by mixing the prepared liquid component and powder component in a ratio of 1:1.8, a thick-film polymer cement waterproof coating can be obtained.

[0035] This technology fundamentally solves the problem of cracking at internal corners. Its high flexibility, moisture-curing properties, and adaptability to thick coatings result in a comprehensive improvement in crack resistance, waterproofing effect, and construction efficiency. Engineering practice and experimental data both demonstrate that this technology provides a reliable, efficient, and economical solution for building waterproofing, and has significant value for widespread application.

[0036] Beneficial effects

[0037] Compared with the prior art, the technical solution provided by this invention has the following advantages:

[0038] The technical solution provided by this invention can solve the problem of cracking at the inside corners of coatings. By increasing the amount of styrene-acrylic emulsion particles, the capillary pressure can be greatly reduced, making the capillary pressure much lower than the gelation stress, thereby preventing the coating from cracking. Furthermore, by adjusting the particle size of the styrene-acrylic emulsion to control the content of other components, the mechanical properties of the coating are prevented from declining, and the performance of the waterproof coating is brought back to balance, preventing the coating from deteriorating. At the same time, by increasing the emulsion content, as well as adding fast-setting cement and thickener, the problem of cracking at the inside corners of the coating can be effectively solved. Moreover, the fast-setting cement is suitable for use with gypsum and retarder, which can improve the drying speed while ensuring that the film does not crack, resulting in a stable waterproof effect and convenient construction. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the preparation method of the present invention. Detailed Implementation

[0040] To make the technical solution of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0041] Combined with appendix Figure 1 A thick-film polymer cement waterproof coating and its preparation method are disclosed, comprising two components: a liquid component and a powder component. The mass ratio of the liquid component to the powder component is 1:1.8.

[0042] By weight, the liquid component comprises the following components: 70-100 parts styrene-acrylic emulsion, 0-15 parts water, 0.3-0.6 parts defoamer, 0.1-0.3 parts thickener, 0.2-3 parts silane coupling agent, 0.1-0.5 parts wetting agent, 0.1-0.5 parts dispersant, 0.1-0.2 parts bactericide, and 0.1-0.2 parts preservative. The average particle size of the styrene-acrylic emulsion is 350-370 nm.

[0043] By weight, the powder composition includes the following components: 15-60 parts of ordinary Portland cement, 2-15 parts of rapid-hardening cement, 1-5 parts of gypsum, 5-30 parts of sand, 20-50 parts of heavy calcium carbonate, 0.01-0.3 parts of retarder, and 0.05-0.4 parts of water-reducing agent.

[0044] The solid content of the styrene-acrylic emulsion is 55±1%, and the average particle size is 350-370mm. The preferred emulsion is YH89, which was jointly developed by Oriental Yuhong Building Materials Co., Ltd. and Shanghai Baolijia Chemical Co., Ltd.

[0045] The defoamer is a mineral oil type, preferably Dow Corning DC-65 defoamer from Guangzhou Dachuan Fine Chemical Co., Ltd.

[0046] The thickener is an associative alkali-swellable thickener, preferably Dow's TT935;

[0047] The silane coupling agent is any one of 3-chloropropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, and acetoxypropyltrimethoxysilane;

[0048] The wetting agent is nonionic, preferably CF-10 from Guangzhou Hengyu Chemical Co., Ltd.

[0049] The dispersant is sodium polyacrylate, preferably WA-8190 from Guangzhou Wanjun Chemical Technology Co., Ltd.

[0050] The fungicide is Kathon, preferably Sampo K15 fungicide;

[0051] The preservative is Kathon, preferably Sampo M30 preservative;

[0052] Ordinary Portland cement is 425 gray cement, preferably Conch Cement's 425 gray cement;

[0053] Rapid-hardening cement is any one of aluminate cement, sulfoaluminate cement, ferroaluminate cement, and fluoroaluminate cement;

[0054] The gypsum can be any one of gypsum, hemihydrate gypsum, or anhydrite;

[0055] The sand can be any one of river sand, manufactured sand, or quartz sand;

[0056] The precipitated calcium carbonate is 200 mesh, preferably 200 mesh precipitated calcium carbonate from Shijiazhuang Yitian Mineral Products Co., Ltd.;

[0057] The retarder is any one of sodium gluconate, carboxymethyl chitosan, sucrose stearate, sodium citrate, and tartaric acid;

[0058] The water-reducing agent is a polycarboxylate water-reducing agent, preferably FDN-C polycarboxylate water-reducing agent from Henan Tongxu Chemical Products Co., Ltd.

[0059] Solutions to coating cracking or cracking at the corners of the coating can be achieved by increasing the average particle size of the emulsion, increasing the elongation at break of the coating film, increasing the liquid-to-powder ratio, and accelerating the drying speed and preventing sagging.

[0060] The primary explanation for coating cracking is capillary theory, which states that during film formation, capillary pressure and gelation stress must reach a balance. If the capillary pressure exceeds the gelation stress, cracking occurs; conversely, the coating will not crack. Reducing capillary pressure can alleviate coating cracking. Capillary pressure is directly proportional to the specific surface area of ​​the emulsion particles and inversely proportional to the particle size. Increasing the average particle size of styrene-acrylic emulsions to 350-370 nm significantly reduces capillary pressure, making it much lower than the gelation stress, thus resolving coating cracking.

[0061] Elongation at break refers to the maximum degree of deformation of the coating film. The greater deformability of the coating film can effectively relieve the internal stress generated during the drying and film formation process of the coating, providing space for stress release. Therefore, the greater the elongation at break of polymer cement waterproof coating, the stronger the stress resistance and the less the degree of cracking of the coating film. The elongation at break of the coating film can be increased by increasing the content of styrene-acrylic emulsion.

[0062] Increasing the proportion of powder in the liquid-powder mixture can reduce the moisture content of the coating and accelerate the drying speed. However, a higher proportion of powder results in poor compatibility between the emulsion and the powder, i.e., poor encapsulation, and a deterioration in the adhesion between the coating and the substrate. Therefore, wetting agents and silane coupling agents are added to improve tensile strength and adhesion strength. Thus, it is not possible to simply increase the powder content, but rather to increase the powder proportion while ensuring the coating performance by adding wetting agents and silane coupling agents. Therefore, the content of wetting agents and silane coupling agents is negatively correlated with the water content.

[0063] Introducing rapid-hardening cement into the formulation increases the cement hydration rate, shortens the coating drying time, and reduces the difference in drying time between the inside and outside, effectively improving the problem of cracking in the coating at internal corners. However, the addition of rapid-hardening cement results in a very short open time for the coating, poor powder dispersion, and a large number of particles, severely affecting the construction efficiency of the samples. Furthermore, the excessively rapid cement hydration rate leads to poor film formation, significantly impacting the toughness of the paint film. Therefore, rapid-hardening cement needs to be used in conjunction with gypsum and a retarder to ensure the waterproof performance of the coating. By screening and adding suitable gypsum and a retarder, and using a high-performance dispersant to improve the dispersion effect, the content of gypsum and the content of the retarder are positively correlated with the content of rapid-hardening cement.

[0064] After waterproof coating is applied to a facade, it tends to flow downwards under the combined influence of sunlight, temperature, wind speed, and gravity, easily causing sagging, resulting in insufficient thickness on the facade, severe accumulation of material in corners, and coating cracking. By selecting a high-performance thickener, the low-shear viscosity is increased while maintaining a relatively constant high-shear viscosity. This ensures smooth application while improving anti-sagging properties, increasing the thickness of the coating on the facade, and effectively reducing material accumulation in corners caused by sagging, thus alleviating coating cracking.

[0065] A method for preparing a thick-film polymer cementitious waterproof coating includes the following steps:

[0066] Add a certain proportion of styrene-acrylic emulsion and water to the liquid mixing tank in sequence. Install the disperser propeller, start the disperser, and maintain the speed at 350-450 r / min, preferably 400 r / min. Then add defoamer, wetting agent, dispersant, and silane coupling agent, and stir for 10 min. Add thickener dropwise, and stir at 650-750 r / min for 10 min. Then add bactericide and preservative, and continue stirring for 10 min, preferably 700 r / min. Then reduce the speed to 250-350 r / min and stir for 5 min for mechanical defoaming to obtain the liquid component of the coating, preferably 300 r / min.

[0067] Ordinary Portland cement, rapid-hardening cement, gypsum, sand, heavy calcium carbonate, retarder, and water-reducing agent are added to the powder mixer in sequence. The mixer is turned on and mixed for 15 minutes. The mixture is then sieved to obtain the powder components of the coating.

[0068] When using it, simply mix the liquid and powder according to the liquid-to-powder ratio to obtain a thick-coat polymer cement waterproof coating.

[0069] During construction, workers simply brush on the waterproof coating.

[0070] Comparative experiment:

[0071] The powder components are mixed in a certain proportion to obtain the powder, and the liquid components are mixed in a certain proportion to obtain the liquid. The liquid and powder are then mixed to form a 1.5 mm thick waterproof coating.

[0072] Experimental Example 1:

[0073] Liquid component: 80 parts of conventional styrene-acrylic emulsion with a particle size of 260-280nm, 19 parts of water, 0.6 parts of defoamer, 0.1 parts of bactericide, and 0.2 parts of preservative;

[0074] Powder: 50 parts ordinary Portland cement, 30 parts sand, 20 parts heavy calcium carbonate, 0.01 parts retarder, 0.2 parts water-reducing agent;

[0075] Liquid to powder ratio 1:1.5;

[0076] Add emulsion and water to the liquid mixing tank in sequence, install the disperser propeller, start the disperser and keep the speed at 400 r / min, then add defoamer, wetting agent, dispersant and silane coupling agent, stir for 10 min, add thickener dropwise, stir at 700 r / min for 10 min, then add bactericide and preservative, continue stirring for 10 min, then reduce the speed to 300 r / min and stir for 5 min to mechanically defoam and obtain the liquid.

[0077] Add ordinary Portland cement, rapid-hardening cement, gypsum, sand, heavy calcium carbonate, retarder, and water-reducing agent to the powder mixer in sequence, turn on the mixer, mix for 15 minutes, and then sieve to obtain powder.

[0078] The obtained liquid and powder are mixed according to the liquid-to-powder ratio to obtain the coating.

[0079] Experimental Example 2:

[0080] Liquid component: 80 parts of YH89 styrene-acrylic emulsion with a particle size of 350-370nm, 19 parts of water, 0.6 parts of defoamer, 0.1 parts of bactericide, and 0.2 parts of preservative;

[0081] Powder: 50 parts ordinary Portland cement, 30 parts sand, 20 parts heavy calcium carbonate, 0.01 parts retarder, 0.2 parts water-reducing agent;

[0082] Liquid to powder ratio 1:1.5;

[0083] The manufacturing process is the same as in Experiment 1, and the final coating is obtained.

[0084] Experimental Example 3:

[0085] Liquid component: 92 parts YH89 styrene-acrylic emulsion, 7 parts water, 0.6 parts defoamer, 0.1 parts bactericide, and 0.2 parts preservative;

[0086] Powder: 50 parts ordinary Portland cement, 30 parts sand, 20 parts heavy calcium carbonate, 0.01 parts retarder, 0.2 parts water-reducing agent;

[0087] Liquid to powder ratio 1:1.5;

[0088] The manufacturing process is the same as in Experiment 1, and the final coating is obtained.

[0089] Experiment Example 4:

[0090] Liquid component: 92 parts YH89 styrene-acrylic emulsion, 7 parts water, 0.6 parts defoamer, 0.1 parts bactericide, and 0.2 parts preservative;

[0091] Powder: 50 parts ordinary Portland cement, 30 parts sand, 20 parts heavy calcium carbonate, 0.01 parts retarder, 0.2 parts water-reducing agent;

[0092] Liquid to powder ratio 1:1.8;

[0093] The manufacturing process is the same as in Experiment 1, and the final coating is obtained.

[0094] Experimental Example 5:

[0095] Liquid component: 92 parts YH89 styrene-acrylic emulsion, 7 parts water, 0.6 parts defoamer, 0.2 parts wetting agent, 0.6 parts coupling agent, 0.1 parts bactericide, and 0.2 parts preservative;

[0096] Powder: 50 parts ordinary Portland cement, 30 parts sand, 20 parts heavy calcium carbonate, 0.01 parts retarder, 0.2 parts water-reducing agent;

[0097] Liquid to powder ratio 1:1.8;

[0098] The manufacturing process is the same as in Experiment 1, and the final coating is obtained.

[0099] Experimental Example 6:

[0100] Liquid component: 92 parts YH89 styrene-acrylic emulsion, 7 parts water, 0.6 parts defoamer, 0.2 parts wetting agent, 0.6 parts coupling agent, 0.1 parts bactericide, and 0.2 parts preservative;

[0101] Powder: 40 parts ordinary Portland cement, 10 parts rapid-hardening cement, 30 parts sand, 20 parts heavy calcium carbonate, 0.01 parts retarder, 0.2 parts water-reducing agent;

[0102] Liquid to powder ratio 1:1.8;

[0103] The manufacturing process is the same as in Experiment 1, and the final coating is obtained.

[0104] Experiment Example 7:

[0105] Liquid component: 92 parts YH89 styrene-acrylic emulsion with a particle size of 7 parts water, 0.6 parts defoamer, 0.2 parts wetting agent, 0.6 parts coupling agent, 0.4 parts dispersant, 0.1 parts bactericide, and 0.2 parts preservative;

[0106] Powder: 40 parts ordinary Portland cement, 10 parts rapid-hardening cement, 30 parts sand, 17 parts heavy calcium carbonate, 3 parts gypsum, 0.1 parts retarder, 0.5 parts water-reducing agent;

[0107] Liquid to powder ratio 1:1.8;

[0108] The manufacturing process is the same as in Experiment 1, and the final coating is obtained.

[0109] Example 1:

[0110] Liquid component: 92 parts YH89 styrene-acrylic emulsion, 7 parts water, 0.6 parts defoamer, 0.2 parts wetting agent, 0.6 parts coupling agent, 0.4 parts dispersant, 0.2 parts thickener, 0.1 parts bactericide, and 0.2 parts preservative;

[0111] Powder: 40 parts ordinary Portland cement, 10 parts rapid-hardening cement, 30 parts sand, 17 parts heavy calcium carbonate, 3 parts gypsum, 0.1 parts retarder, 0.5 parts water-reducing agent;

[0112] Liquid to powder ratio 1:1.8;

[0113] Add emulsion and water sequentially to the liquid mixing tank, install the disperser propeller, start the disperser, maintain the speed at 400 r / min, then add defoamer, wetting agent, dispersant, and silane coupling agent, stir for 10 min, add thickener dropwise, stir at 700 r / min for 10 min, then add bactericide and preservative, continue stirring for 10 min, then reduce the speed to 300 r / min and stir for 5 min for mechanical defoaming to obtain the liquid components.

[0114] Ordinary Portland cement, rapid-hardening cement, gypsum, sand, heavy calcium carbonate, retarder, and water-reducing agent are added to the powder mixer in sequence. The mixer is turned on and mixed for 15 minutes. The mixture is then sieved to obtain the powder components.

[0115] The liquid and powder are prepared according to the above-mentioned liquid and powder components, and then mixed to obtain the coating.

[0116] Comparative test of experimental examples:

[0117] The above experimental examples were tested for tensile strength, elongation at break, and bond strength according to the performance indicators specified in Type II of GB / T 23445-2009 "Polymer Cement Waterproof Coatings". Tests for surface drying time, complete drying time, workable time, and crack resistance at internal corners were conducted under standard test conditions (temperature 23±2℃, humidity 50±10%). The corresponding performance test results are as follows:

[0118] Testing items Experimental Example 1 Experimental Example 2 Experimental Example 3 Experiment Example 4 Experimental Example 5 Experimental Example 6 Experimental Example 7 Example 1 Elongation at break / % 83 90 148 105 127 106 115 113 Tensile strength / MPa 2.9 2.7 2.4 2.2 2.5 2.2 2.6 2.5 Bond strength 0.9 1 1.1 0.7 0.9 0.8 1.0 0.9 Surface drying time / h 3.5 3.6 3.4 3.1 3.2 2.6 3.2 3.1 Practical time / h 7.8 7.5 7.6 6.2 6.0 3.8 4.7 4.5 Construction time / min ≥180 ≥180 ≥180 ≥180 ≥180 ≤40min ≥90min ≥90min Minimum non-cracking film thickness (mm) 0.7 0.9 1 1.1 1.1 1.4 1.6 1.6 Flat coating appearance normal normal normal There are particles normal There are particles normal normal Cracks in the inner corner Severe cracking Severe cracking cracking cracking cracking Slight cracks Slight cracks No cracks Material stacking situation in the inside corner serious material stockpiling serious material stockpiling serious material stockpiling Material stacking Material stacking Material stacking Material stacking Unstocked

[0119] The comparison between Experiment 1 and 2 shows that increasing the particle size of the emulsion particles can increase the minimum non-cracking film thickness of the coating.

[0120] The comparison between Experiment 2 and 3 shows that increasing the amount of emulsion improves the elongation of the coating film and can reduce the degree of cracking at the inside corners.

[0121] The comparison of Experiments 3 and 4 shows that increasing the liquid-to-powder ratio can reduce the moisture in the coating and speed up the drying process. However, with a higher proportion of powder, the compatibility between the emulsion and the powder is poor, and the adhesion between the coating and the substrate is also poor.

[0122] The comparison of Experiments 4 and 5 shows that adding coupling agents and wetting agents to coatings can improve the compatibility of emulsions and powders, enhance the elongation properties of the coating film, and improve the adhesion between the coating and the substrate.

[0123] The comparison of Experiments 5 and 6 shows that by introducing fast-hardening cement into the formula, the cement hydration speed is increased, the coating drying time is shortened, the difference between the inner and outer drying times is reduced, the minimum non-cracking film thickness can be effectively increased, and the problem of cracking of the coating at the inside corner can be improved.

[0124] However, the addition of fast-hardening cement resulted in a very short open time for the coating, poor powder dispersion, and a large number of particles, which seriously affected the construction efficiency of the sample. Furthermore, the cement hydration rate was too fast, resulting in poor film-forming properties and severely affecting the toughness of the paint film.

[0125] The comparison of Experiments 6 and 7 shows that by adding gypsum, increasing the dosage of retarders and water-reducing agents, and using high-performance dispersants, the dispersion effect of the coating can be effectively improved, the application time can be extended, and the thick coating performance of the product can be enhanced.

[0126] The comparison of Experiments 7 and 8 shows that by adding a high-performance thickener, the low-shear viscosity can be increased while the high-shear viscosity remains basically unchanged. This ensures smooth application and improves anti-sagging properties, which can effectively reduce material accumulation in the corners caused by flow on the vertical surface, thereby alleviating coating cracking.

[0127] Example 2:

[0128] By mass, the liquid component comprises the following components: 70 parts styrene-acrylic emulsion, 1 part water, 0.3 parts defoamer, 0.1 parts thickener, 3 parts silane coupling agent, 0.5 parts wetting agent, 0.1 parts dispersant, 0.1 parts bactericide, and 0.1 parts preservative.

[0129] The average particle size of the styrene-acrylic emulsion is 350 nm.

[0130] By mass, the powder composition includes the following components: 15 parts ordinary Portland cement, 2 parts rapid-hardening cement, 1 part gypsum, 5 parts sand, 20 parts heavy calcium carbonate, 0.01 parts retarder, and 0.05 parts water-reducing agent.

[0131] Add emulsion and water sequentially to the liquid mixing tank, install the disperser propeller, start the disperser, maintain the speed at 400 r / min, then add defoamer, wetting agent, dispersant, and silane coupling agent, stir for 10 min, add thickener dropwise, stir at 700 r / min for 10 min, then add bactericide and preservative, continue stirring for 10 min, then reduce the speed to 300 r / min and stir for 5 min for mechanical defoaming to obtain the liquid components.

[0132] Ordinary Portland cement, rapid-hardening cement, gypsum, sand, heavy calcium carbonate, retarder, and water-reducing agent are added to the powder mixer in sequence. The mixer is turned on and mixed for 15 minutes. The mixture is then sieved to obtain the powder components.

[0133] The liquid and powder are prepared according to the above-mentioned liquid and powder components, and then mixed to obtain the coating.

[0134] Example 3:

[0135] By mass, the liquid component comprises the following components: 100 parts styrene-acrylic emulsion, 15 parts water, 0.6 parts defoamer, 0.3 parts thickener, 0.2 parts silane coupling agent, 0.1 parts wetting agent, 0.5 parts dispersant, 0.2 parts bactericide, and 0.2 parts preservative.

[0136] The average particle size of the styrene-acrylic emulsion is 370 nm.

[0137] By weight, the powder composition includes the following components: 60 parts ordinary Portland cement, 15 parts rapid-hardening cement, 5 parts gypsum, 30 parts sand, 50 parts heavy calcium carbonate, 0.3 parts retarder, and 0.4 parts water-reducing agent.

[0138] Add emulsion and water to the liquid mixing tank in sequence, install the disperser propeller, start the disperser and keep the speed at 400 r / min, then add defoamer, wetting agent, dispersant and silane coupling agent, stir for 10 min, add thickener dropwise, stir at 700 r / min for 10 min, then add bactericide and preservative, continue stirring for 10 min, then reduce the speed to 300 r / min and stir for 5 min to mechanically defoam and obtain the liquid.

[0139] Add ordinary Portland cement, rapid-hardening cement, gypsum, sand, heavy calcium carbonate, retarder, and water-reducing agent to the powder mixer in sequence, turn on the mixer, mix for 15 minutes, and then sieve to obtain powder.

[0140] The obtained liquid and powder materials are mixed to obtain the coating.

[0141] The coatings obtained in Examples 1-3 meet the performance standards specified in Type II of GB / T 23445-2009 "Polymer Cement Waterproof Coatings", and the coatings prepared do not have the problem of cracking at the inside corners after construction.

[0142] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A thickly applied polymer-modified cementitious waterproofing coating, characterized in that, The liquid material component includes a styrene-acrylic emulsion, water, a defoaming agent, a thickening agent, a silane coupling agent, a wetting agent, a dispersing agent, a bactericide and a preservative, and the powder component includes Portland cement, fast hardening cement, gypsum, sand, heavy calcium, a retarder and a water reducing agent; The mass ratio of the liquid material component to the powder component is 1:1.8; The average particle size of the styrene-acrylic emulsion is 350-370 nm.

2. The thickly-coated polymer cement waterproofing coating according to claim 1, characterized in that, The liquid material component contains the following components in parts by mass: 70-100 parts of the styrene-acrylic emulsion, 0-15 parts of water, 0.3-0.6 parts of the defoaming agent, 0.1-0.3 parts of the thickening agent, 0.2-3 parts of the silane coupling agent, 0.1-0.5 parts of the wetting agent, 0.1-0.5 parts of the dispersing agent, 0.1-0.2 parts of the bactericide and 0.1-0.2 parts of the preservative.

3. The thickly-coated polymer cement waterproofing coating according to claim 1, characterized in that, The powder component contains the following components in parts by mass: 15-60 parts of the Portland cement, 2-15 parts of the fast hardening cement, 1-5 parts of the gypsum, 5-30 parts of the sand, 20-50 parts of the heavy calcium, 0.01-0.3 parts of the retarder and 0.05-0.4 parts of the water reducing agent.

4. The thickly applied polymer cement waterproof coating according to claim 2, characterized in that, The content of the wetting agent and the content of the silane coupling agent are negatively correlated with the content of the water.

5. The thickly applied polymer cement waterproof coating according to claim 3, characterized in that, The content of the gypsum and the content of the retarder are positively correlated with the content of the fast hardening cement.

6. The thick-coat type polymer cement waterproof coating according to claim 1, characterized in that, The solid content of the styrene-acrylic emulsion is 55±1%; The defoaming agent is of the mineral oil type; The thickening agent is an associated alkali-swellable thickening agent; The silane coupling agent is any one of 3-chloropropyltrimethoxysilane, γ-aminopropyltrimethoxysilane or acetoxypropyltrimethoxysilane; The wetting agent is non-ionic; The dispersing agent is a sodium salt of polyacrylic acid; The bactericide is Karsoon; The preservative is Karsoon; The Portland cement is 425 cement; The fast hardening cement is any one of aluminate cement, sulphoaluminate cement, ferroaluminate cement or fluoroaluminate cement; The gypsum is any one of raw gypsum, hemihydrate gypsum or anhydrite; The sand is any one of river sand, machine-made sand or quartz sand; The heavy calcium is 200-mesh heavy calcium; The retarder is any one of sodium gluconate, carboxymethyl chitosan, sucrose stearate, sodium citrate or tartaric acid; The water reducing agent is a polycarboxylic acid water reducing agent.

7. A method for preparing the thickly-applied polymer cement waterproof coating according to any one of claims 1 to 6, characterized by, The liquid material component of the coating is obtained by sequentially adding a certain number of components of the styrene-acrylic emulsion and water into a liquid material stirring cylinder, installing a disperser propeller, starting the disperser, keeping the rotating speed at 350-450 r / min, then adding the defoaming agent, the wetting agent, the dispersing agent and the silane coupling agent, stirring for 10 min, adding the thickening agent dropwise, stirring at 650-750 r / min for 10 min, then adding the bactericide and the preservative, continuing to stir for 10 min, and then reducing the rotating speed to 250-350 r / min, stirring for 5 min to mechanically defoam; The powder component of the coating is obtained by sequentially adding the Portland cement, the fast hardening cement, the gypsum, the sand, the heavy calcium, the retarder and the water reducing agent into a powder mixer, starting the mixer, mixing for 15 min, and then sieving.

8. A method of preparing a thickly applied polymer-modified cementitious waterproofing coating as claimed in claim 7, characterised in that, The prepared liquid component and powder component are mixed in a ratio of 1:1.8 to obtain a thick coating type polymer cement waterproof coating.

Images